Polypropylene copolymer

The present invention relates to a new class of propylene copolymers and their manufacture.

Well-known propylene copolymers of commerce are characterized by improved impact strength and lower brittlencss compared to the propylene homopolymer counterparts. Thus propylene copolymers, in particular with the α-olcfm comonomer being ethylene, have found widespread applications for example in the production of polymer films, of articles produced by blow moulding or injection moulding, of fibers and of pipes. Among these applications, the most important is the use for the production of films. Such films may be used for packaging such as food packaging. In general, for the production of propylene copolymers propylene is copolymeriscd with an α-olefin in a slurry or gas phase polymerisation reaction in the presence of a suitable catalyst. The amount of comonomer, i.e. α-olefin, normally does not exceed 30 mol% of the total polymer.

Commercial propylene copolymers usually have a predetermined comonomer distribution which can be slightly tuned to a limited extent by varying the temperature of the process.

In such propylene copolymers the α-olefin is randomly distributed, i.e. the α-olcfin units do not form blocks comprising only such comonomer units but instead arc evenly distributed as single units within the polypropylene blocks which essentially make up the polymer chains. Moreover in such propylene copolymers the α-olefin comonomcrs concentrate in short polymer chains.

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It is known that important properties such as the transparency and the toughness, i.e. the impact strength, for instance of a film comprising said propylene copolymers are influenced by the co monomer distribution. It is also known, that the impact strength can be increased with increasing the amount of the comonomer content, However such an improvement in impact strength is paid with a deterioration of the processing properties as the stickiness of material is highly increased leading to reactor fouling. Moreover also the transparency suffers from rather high amounts of comonomers, like ethylene. It also must considered that the melting point of known propylene copolymers are vciy sensitive to the increase of comonomer content, i.e. high levels of comonomer lowers the melting point and/or the crystallization point undesirably.

Thus up to now it was impossible to provide propylene copolymers with improved balance between mechanical properties, thermal properties and processing properties. It was in particular not possible to enhance the impact strength of propylene copolymers by keeping constant the melting properties of said propylene copolymers, the transparency of films based on said propylene copolymers and the processing properties of said propylene copolymer films simultaneously.

Therefore the object of the present invention is to provide a propylene copolymer having an improved balance between mechanical properties, thermal properties and processing properties. It is in particular an object of the invention to improve the toughness of materials based on said propylene copolymer by keeping the transparency at high level More particularly it is sought for a propylene copolymer with improved toughness having excellent process properties, i.e. the copolymer is less sticky compared to the propylene copolymers being state of the art and causes no reactor fouling. Moreover the melting properties of the propylene copolymer shall be preferably only little influenced by the comonomer content.

The finding of the present invention is that the xylene soluble fraction of the propylene copolymer must have rather high intrinsic viscosity. Another finding of

thc present invention is that the distribution curve of the average isotactic chain length of the propylene copolymer shows at least two distinct maxima, i.e. the comonomcr units are not equally distributed among the individual chains of the propylene copolymer.

In a first embodiment of the present invention a propylene copolymer is provided comprising monomer units of propylene and at least one other α-olcfm as a comonomer, wherein

(a) the weight ratio of the comonomcr to the sum of monomers present in said polypropylene copolymer (comonomer /(comonomcr + propylene)) is at least 2.0 wl.-%,

(b) said propylene copolymer comprises a fraction having a lamella thickness of more than 9,0 nm,

(c) said fraction with a lamella thickness of more than 9.0 nm has a higher melt enthalpy [J/g] as each fraction with a lamella thickness below

9.0 nm, and

(d) said fractions arc determined by stepwise isothermal segregation technique (SlST).

Accordingly the propylene copolymer according to the first embodiment can be also defined by a propylene copolymer comprising monomer units of propylene and at least one other α-olefin as a comonomcr, wherein

(a) the weight ratio of the comonomer to the sum of monomers present in said polypropylene copolymer (comonomer /(comonomer + propylene)) is at least 2.0 wt.-%,

(b) said propylene copolymer comprises a fraction having a lamella thickness of more than 9.0 nm,

(c) said fraction with a lamella thickness of more than 9.0 nm has a higher melt enthalpy [J/g] as each fraction with a lamella thickness below 9.0 nm,

(d) said fractions arc determined by stepwise isothermal segregation technique (SIST), wherein the propylene copolymer

(i) is melted at 225 ⁰ C for 5 min.,

(ii) then cooled with 80 °C/min to 145 ⁰ C (iii) held for 2 hours at 145 ⁰ C,

(iv) then cooled with 80 °C/min to 135 ⁰ C

(v) held for 2 hours at 135 ⁰ C,

(vi) then cooled with 80 °C/min to 125 ⁰ C

(vii) held for 2 hours at 125 ⁰ C, (viii) then cooled with 80 °C/min to 1 15 ⁰ C

(ix) held for 2 hours at 1 15 ⁰ C,

(x) then cooled with 80 °C/min to 105 ⁰ C

(xi) held for 2 hours at 105 ⁰ C,

(xii) then cooled down to -10 ⁰ C, i.e. cooled down to -10 ⁰ C with maxima] cooling rate by a compression-cooling unit

(xiii) then heated at a heating rate of 10 °C/min up to 200 ⁰ C obtaining a melting curve of said cooled propylene copolymer (c) the absolute minimum and the relative minima of said melting curve arc converted in the lamella thickness according to the Thomson-Gibbs equation (Eq 1.)

wherein T ₀ = 457 K ₁ δH ₀ = 184 x 10 ⁶ J/m ³ , σ - 0.0496 J/m ² ,

T _m is the measured temperature (K) and L is the lamella thickness (nm), and wherein

(i) lhc absolute minimum indicates the lamella thickness of the fraction having a lamella thickness of more than 9,0 nm and (ii) the relative minima indicate the lamella thickness of the fractions having a lamella thickness of below 9.0 nm, and (1) the melt enthalpy [J/g] of each fraction is defined by the area above each minimum of the melting curve.

The exact measuring method of the stepwise isothermal segregation technique (SIST), in particular the determination of the melt enthalpy [J/g], is given in the example section.

Surprisingly, it has been found that propylene copolymers with such characteristics have superior properties compared to the propylene copolymers known in the art. Especially the propylene copolymers of the instant invention have superior impact resistance and brittle behavior compared to commercially available propylene copolymers (see Figures 17 and 18) Moreover the propylene copolymers keep over a broad range of comonomer content at a high level their transparency in terms of haze (Figure 20). Also the melting and crystallization temperature of the inventive propylene copolymers are less influenced by the comonomer content and kept at high level (sec Figures 1 1 to 14). Thus the propylene copolymer combines the benefit of reduced stickiness, i.e. better proccssability, and enhanced mechanical properties for instance in terms of improved impact resistance.

The first requirement according to the first embodiment of the present invention is that the propylene copolymer comprises beside propylene a certain amount of comonomer being an α-olefm. Preferred α-olefins are selected from the group consisting of ethylene, C ₄ α-olefm, C ₅ α-olefin, Ce α-olefm to Cs α-olefin, more preferably selected from the group consisting of ethylene, 1-bulenc, 1-hepten, 1- hcxenc and 1-octcnc, still more preferably selected from the group consisting of ethylene and Q α-olefin, yet more preferably selected from the group consisting of

cthyicnc and 1-butenc, and most preferably ethylene. The propylene copolymer may comprise mixtures of the above mentioned comonomers, however it is preferred that the propylene copolymer comprises only one species of α-olcfm as a comonomcr. In the most preferred embodiment the propylene copolymer comprises only propylene and ethylene.

The amount of comonomer present in the propylene copolymer must be at least 2.0 wt, -% to obtain the desired properties in particular with regard to the mechanical properties, like superior impact resistance. More precisely the weight ratio of the comonomer (being a α-olcfin as defined above) to the sum of monomers present in said polypropylene copolymer (comonomer / (comonomer + propylene)) is at least 2. 0 wt.-%, more preferably is at least 3.0 wt.-% and still more preferably is at least 5.0 wl.-%. On the other hand the comonomcr should be preferably not to high otherwise the polymer might loose its rigidity. Accordingly the weight ratio of the comonomer to the sum of monomers present in said polypropylene copolymer (comonomcr / (comonomer + propylene)) shall preferably not exceed 30.0 wt.-%, more preferably not exceed 15.0 wt.-%, still more preferably not exceed 10.0 wt.-% and yet more preferably shall not exceed 8.0 wl.-%. Preferred ranges are 2.0 to 20.0 wt.-%, more preferred 2.0 to 12.0 wt.-%, yet more preferred 2.0 to 10.0 wt.-%, still more preferred 3.00 to 10.0 wt.-%, still yet more preferred 3.0 to 8.0 wt.-%, and most preferred 5.0 to 7.0 wl.-%. Accordingly it is preferred that the propylene copolymer according to this invention is a random propylene copolymer. The comonomer content can be determined with FT infrared spectroscopy, as described below in the example section.

Furthermore the propylene copolymer according to this invention is further specified by its lamellar thickness distribution. The stepwise isothermal segregation technique (SIST) provides a possibility to determine the lamellar thickness distribution. The precise measuring method is specified in the example section (in particular the definition of the lamella thickness of each fraction and its melt enthalpy). Thereby

rather high amounts (rather high melt enthalpy [J/g]) of polymer fractions crystallizing at high temperatures indicate a rather high amount of thick lamellae.

It has been recognized that the improved balance between the mechanical and process properties can be only achieved with a new class of propylene copolymer having a specific lamellar thickness distribution, i.e. a propylene copolymer comprising a fraction with a lamella thickness of more than 9.0 nm. More preferably the propylene copolymer comprises a fraction with a lamella thickness of more than 9.2 nm, still more preferably of more than 9.5 nm. Preferred ranges for said fraction are from 9.0 to 12.0 nm, more preferred from 9.2 to 1 1.0 nm.

A further requirement of the above defined fraction is that it represents the largest fraction of all fractions, in particular compared to the fractions with a lamella thickness below 9.0 nm, of the propylene copolymer. Accordingly the propylene copolymer comprises a fraction with a lamella thickness of more than 9.0 nm (the other preferred values for the lamella thickness arc given above) having a higher melt enthalpy [J/g] as each lamella fraction with a lamella thickness below 9.0 nm. More preferably the fraction with a lamella thickness of more than 9. 0 nm has melt enthalpy of more than 20.0 J/g, still more preferably of more than 21.0 J/g. Concerning the fractions below 9.0 nm it is preferred that the they have a melt enthalpy of not more than 30.0 J/g. It is in particular preferred that the fractions with a lamella thickness in the range of 6.5 to 9.0 nm have a melt enthalpy in the range of 15.0 to 30.0 J/g.

The propylene copolymer according to this invention is further preferably defined by its isotactic sequence length distribution.

The measurement of isotactic sequence length distribution is performed in the instant invention by using the temperature rising elution fraction (TREF) technique (the exact description is given in the experimental part), which fractionates propylene

copolymcrs according to the solubility differences. Il has been clearly demonstrated for propylene polymers that the temperature rising elution fraction (TREF) technique fractionates the propylene polymer according to the longest crystallisable sequences in the chain, which increases almost linearly with the elution temperature (P. ViUc et al, Polymer 42 (2001) 1953-1967). Hence the higher the maximum temperature the longer are the isotactic sequences. The results further showed that the temperature rising elution fraction (TREF) technique does not strictly fractionate polypropylene according to tacticity but according to the longest crystallisablc sequences in the chain, The solubility of a polypropylene polymer chain hence is influenced only by the concentration and distribution of stcrical defects. Insofar the temperature rising elution fraction (TREF) technique is an appropriate method to characterize the inventive propylene copolymer further,

Thus it is preferred that the propylene copolymer posses a distribution curve of the average isotactic chain length featured by at least two distinct maxima, i.e. the comonomcr units arc not equally distributed among the individual chains of the propylene copolymer. Accordingly it is preferred that the temperature rising elution fractionation (TREF) curve of the inventive propylene copolymer comprises at least two local maxima (a) one absolute maximum over 100 ⁰ C, more preferably between 100 to 1 10 ⁰ C, and,

(b) one relative maximum between 50 and 85 ⁰ C, more preferably between 55 to 80 ⁰ C, and yet more preferably between 60 and 80 ⁰ C,

More preferably the area below the absolute maximum of that the temperature rising elution fractionation (TREF) function is in the range of 50 to 85 wt-%, more preferably in the range of 50 to 80 wt.-% and yet more preferably in the range of 55 to 80 wt.-%. With regard to the area below the relative maximum of the temperature rising elution fractionation (TREF) function as defined above it is preferred that it is in the range of 10 to 30 wl.-%, more preferably in the range of 10 to 25 wt.-%.

Moreover it is preferred thai the propylene copolymer has xylene solubles of some extent, i.e. of al least 2.0 wt.-%. Xylene solubles are the part of the polymer soluble in cold xylene determined by dissolution in boiling xylene and letting the insoluble part crystallize from the cooling solution (for the method see below in the experimental part). The xylene solubles fraction contains polymer chains of low stereo-regularity and is an indication for the amount of non-crystalline areas.

Preferably, the propylene copolymer has xylene solubles of more than 3.0 wl.-%, more preferably of more than 4.0 wt.-% and yet more preferably of more than

6.0 wt.-%. On the other hand, the amount of xylene solubles should not be too high since they represent a potential contamination risk. Accordingly it is preferred that the xylene solubles are not more than 40.0 wt.~%, still more preferably not more than 35.0 wt.-% and yet more preferably not more than 20.0 wt.-%, In preferred embodiments the xylene solubles are in the range of 5,0 to 40.0 wt.-%, more preferably in the range of 6.0 to 30.0 wt.-% and still more preferably in the range of 6.0 to 20.0 wt.-% like 6.5 to 10 wt.-%.

Additionally it is appreciated that the xylene soluble fraction of the inventive propylene copolymer is characterized by a rather high intrinsic viscosity. Common propylene copolymer have normally xylene soluble fractions with a rather low intrinsic viscosity, which is reflected in increased stickiness leading to reactor fouling.

The intrinsic viscosity is a measure of the capability of a polymer in solution to enhance the viscosity of said solution. The viscosity behavior of macro molecular substances in solution is one of the most frequently used approaches for characterization. The intrinsic viscosity number is defined as the limiting value of the specific viscosity/concentration ratio at zero concentration. It thus becomes necessary to find the viscosity at different concentrations and then extrapolate to zero

concentration. The variation of the viscosity number with concentration depends on the type of molecule as well as the solvent, ϊn general, the intrinsic viscosity of linear macromolccular substances is related to the molecular weight or degree of polymerization. With macromolecules, viscosity number measurements provide a method for the rapid determination of molecular weight when the relationship between viscosity and molecular weight has been established. The intrinsic viscosity in the instant invention is measured according to DlN ISO 1628/1 , October 1999 (in Decalin at l 35 ⁰ C).

Accordingly the propylene copolymer according to this invention preferably fulfils the equation (2), more preferably the equation (2a), yet more preferably the equation (2b), still more preferably the equation (2c), still yet more preferably the equation (2d), like the equation (2e)

IV (XS) [dl/g] - 0.3085 ^■ IV [dl/g] > -0.1 343 (2) IV (XS) [dl/g] - 0.3085 ^• IV [dl/g] > -0.1101 (2a)

IV (XS) [dl/g] - 0,3085 ^■ IV [dl/g] > -0.0501 (2b)

IV (XS) [dl/g] - 0.33 ^■ IV [dl/g] > -0,05 (2c)

IV (XS) [dl/g] - 0.3 ^• IV [dl/g] > -0.2 (2d)

IV (XS) [dl/g] - 0.3 ^• IV [dl/g] > -0.1 (2c) wherein

IV (XS) is the intrinsic viscosity of the xylene soluble fraction of the polypropylene copolymer measured according DIN ISO 1628/1 and

IV is the intrinsic viscosity of the total polypropylene copolymer measured according DIN lSO 1628/1.

As can be seen from figure 7 the equations (2), (2a), (2b), (2c), (2d) and (2c), respectively define in a simple manner the benefit of the invention, The inventive propylene copolymers have a xylene soluble fraction with a significant higher intrinsic viscosity compared to the known propylene copolymers being stale of the

art. This positive property is reached independently from the comonomer content present in the propylene copolymer of the instant invention.

Moreover the high intrinsic viscosity values of the xylene soluble fraction of the inventive propylene copolymers are also reached in broad range of melt flow rate. This can be easily learned from figure 8. Thus it is preferred that the propylene copolymer of the instant invention fulfils the equation (3), more preferably the equation (3a), yet more preferably the equation (3b), still more preferably (3c),

IV (XS) [dl/g] + 0.0083 MFR [g/10min] > 0.601 (3) IV (XS) [dl/g] + 0.0083 MFR [g/10min] > 0.621 (3a)

IV (XS) [dl/g] + 0.0083 MFR [g/IOmin] > 0.641 (3b)

IV (XS) [dl/g] + 0.01 MFR [g/IOmin] > 0.64 (3c) wherein

IV (XS) is the intrinsic viscosity of the xylene soluble fraction of said polypropylene copolymer measured according DlN ISO 1628/1 , and

MFR is the melt flow rate measured according to ISO 1 133 at 230 ⁰ C and 2.16 kg load.

Additionally it is preferred that the xylene soluble fraction of the inventive propylene copolymer as defined herein has a intrinsic viscosity of at least 0.4 dl/g, more preferably of at least 0.5 dl/g. Moreover it is appreciated that the intrinsic viscosity of the total propylene copolymer reaches a certain value. Thus it is preferred that the intrinsic viscosity of the total propylene copolymer is at least 1.0 dl/g, more preferably at least 1.2 dl/g.

In a second embodiment of the present invention a propylene copolymer is provided comprising monomer units of propylene and at least one other α-olcfm as a comonomer, wherein

(a) lhc weight ratio of the comonomer Io the sum of monomers present in said polypropylene copolymer (comonomer/(comonomer + propylene)) is at least 2.0 wt.-%, and

(a) the temperature rising elution fractionation (TREF) curve of said propylene copolymer comprises at least two local maxima

(i) one absolute maximum over 100 ⁰ C, and (ii) one relative maximum between 50 and 80 ⁰ C.

Surprisingly, it has been found that that propylene copolymers with such characteristics have superior properties compared to the propylene copolymers known in the art. Especially the propylene copolymers of the instant invention have superior impact resistance and brittle behaviour compared to commercially available propylene copolymers (see Figures 17, 18) Moreover the propylene copolymers keep over a broad range of comonomer content at a high level their transparency in terms of haze (Figure 20). Also the melting and crystallization temperature of the inventive propylene copolymers are less influenced by the comonomer content and kept at high level (see Figures 1 1 to 14). Thus the propylene copolymer combines the benefit of reduced stickiness, i.e. better processability, and enhanced mechanical properties for instance in terms of improved impact resistance.

The first requirement according to the second embodiment of the present invention is that the propylene copolymer comprises beside propylene a certain amount of comonomer being an α-olcfin. Preferred α-olefins arc selected from the group consisting of ethylene, Ci α-olefin, Cs α-olcfin and C^ α-olefin to Cs α-olefin, more preferably selected from the group consisting of ethylene, 1-butene, 1 -hcptene, 1- hcxene and 1 -octene, still more preferably selected from the group consisting of ethylene and C ₄ α-olcfin, yet more preferably selected from the group consisting of ethylene and 1-butene, and most preferably ethylene. The propylene copolymer may comprise mixtures of the above mentioned comonomcrs, however it is preferred that the propylene copolymer comprises only one species of α-olcfin as a comonomer. In

the most preferred embodiment the propylene copolymer comprises only propylene and ethylene.

The amount of comonomcr present in the propylene copolymer must be at least 2.0 wt.-% to obtain the desired properties in particular with regard to the mechanical properties, like superior impact resistance. More precisely the weight ratio of the comonomcr (being a α-olefin as defined above) to the sum of monomers present in said polypropylene copolymer (comonomcr / (comonomcr + propylene)) is at least 2,0 wt.-%, more preferably is at least 3.0 wt.-% and still more preferably is at least 5.0 wt.-%. On the other hand the comonomer should be preferably not to high otherwise the polymer might loose its rigidity. Accordingly the weight ratio of the comonomcr to the sum of monomers present in said polypropylene copolymer (comonomcr / (comonomcr H- propylene)) shall preferably not exceed 30.0 wt.~%, more preferably not exceed 15.0 wt.-%, still more preferably not exceed 10.0 wl.-% and yet more preferably shall not exceed 8.0 wt.-%. Preferred ranges are 2.0 to

20.0 wt.-%, more preferred 2.0 to 12.0 wl.-%, yet more preferred 2.0 to 10.0 wt.-%, still more preferred 3.0to 10.0 wt.~%, still yet more preferred 3.0 to 8.0 wt.-%, and most preferred 5.0 to 7.0 wt.-%. Accordingly it is preferred that the propylene copolymer according to this invention is a random propylene copolymer. The comonomer content can be determined with FT infrared spectroscopy, as described below in the example section.

The propylene copolymer according to this invention is further defined by its isotactic sequence length distribution.

The measurement of isotactic sequence length distribution is performed in the instant invention by using the temperature rising elution fraction (TREF) technique (the exact description is given in the experimental part), which fractionates propylene copolymers according to the solubility differences. It has been clearly demonstrated for propylene polymers that the temperature rising elution fraction (TREF) technique

fractionates the propylene polymer according to the longest crystallisable sequences in the chain, which increases almost linearly with the clution temperature (P. Villc ct al., Polymer 42 (2001) 1953-1967). Hence the higher the maximum temperature the longer are the isotactic sequences. The results further showed that the temperature rising elution fraction (TREF) technique docs not strictly fractionate polypropylene according to lacticity but according to the longest crystallisablc sequences in the chain. The solubility of a polypropylene polymer chain hence is influenced only by the concentration and distribution of stcrical defects. Insofar the temperature rising elution fraction (TREF) technique is an appropriate method to characterize the inventive propylene copolymer further.

The propylene copolymer according to the instant invention differs from known propylene copolymers in its temperature rising clution fractionation (TREF) function (sec Figures 4 and 5). The inventive propylene copolymer posses a distribution curve of the average isolactic chain length featured by at least two distinct maxima, i.e. the comonomer units arc not equally distributed among the individual chains of the propylene copolymer. Accordingly it is preferred that the temperature rising elution fractionation (TREF) curve of the inventive propylene copolymer comprises at least two local maxima (i) one absolute maximum over 100 ⁰ C, more preferably between 100 to

1 10 ⁰ C, and, (ii) one relative maximum between 50 and 85 °C _: more preferably between 55 to 80 ⁰ C, and yet more preferably between 60 and 80 ⁰ C.

More preferably the area below the absolute maximum of that the temperature rising clution fractionation (TREF) function is in the range of 50 to 85 wt,-%, more preferably in the range of 50 to 80 wt,-% and yet more preferably in the range of 55 to 80 wl.-%. With regard to the area below the relative maximum of the temperature rising clution fractionation (TREF) function as defined above it is preferred that it is in the range of 10 to 30 wt.-%, more preferably in the range of 10 to 25 wt.-%.

Furthermore the propylene copolymer according to this invention is preferably further specified by its lamellar thickness distribution. The stepwise isothermal segregation technique (SIST) provides a possibility to determine the lamellar thickness distribution. The precise measuring method is specified in the example section (in particular the definition of the lamella thickness of each fraction and its melt enthalpy). Thereby rather high amounts (rather high melt enthalpy [J/g]) of polymer fractions crystallizing at high temperatures indicate a rather high amount of thick lamellae.

It has been recognized that the improved balance between the mechanical and process properties can be achieved with a propylene copolymer having a specific lamellar thickness distribution, i.e. a propylene copolymer comprising a fraction with a lamella thickness of more than 9.0 nm. More preferably the propylene copolymer comprises a fraction with a lamella thickness of more than 9.2 nm, still more preferably of more than 9.5 nm. Preferred ranges for said fraction are from 9.0 to 12.0 nm, more preferred from 9.2 to 1 1.0 nm,

A further requirement of the above defined fraction is that it represents the largest fraction of all fractions, in particular compared to the fractions with a lamella thickness below 9.0 nm, of the propylene copolymer. Accordingly the propylene copolymer comprises a fraction with a lamella thickness of more than 9.0 nm (the other preferred values for the lamella thickness arc given above) having a higher melt enthalpy [J/g] as each lamella fraction with a lamella thickness below 9.0 nm. More preferably the fraction with a lamella thickness of more than 9.0 nm has melt enthalpy of more than 20.0 J/g, still more preferably of more than 21.0 J/g. Concerning the fractions below 9.0 nm it is preferred that the they have a melt enthalpy of not more than 30.0 J/g. It is in particular preferred that the fractions with a lamella thickness in the range of 6.5 to 9.0 nm have a melt enthalpy in the range of 15.0 to 30.0 J/g

Moreover it is preferred that the propylene copolymer has xylene solubles of some extent, i.e. of at least 2.0 wt.-%. Xylene solubles arc the part of the polymer soluble in cold xylene determined by dissolution in boiling xylene and letting the insoluble part crystallize from the cooling solution (for the method see below in the experimental part). The xylene solubles fraction contains polymer chains of low stereo-regularity and is an indication for the amount of non-crystalline areas.

Preferably, the propylene copolymer has xylene solubles of more than 6.0 wt-%, On the other hand, the amount of xylene solubles should not be too high since they represent a potential contamination risk. Accordingly it is preferred that the xylene solubles arc not more than 40.0 wt.-%, still more preferably not more than 35.0 wt.- % and yet more preferably not more than 20.0 wt.-%. In preferred embodiments the xylene solubles are in the range of 5.0 to 40,0 wt.-%, more preferably in the range of 6.0 to 30.0 wt.-% and still more preferably in the range of 6.0 to 20.0 wt,-%.

Additionally it is appreciated that the xylene soluble fraction of the inventive propylene copolymer is characterized by a rather high intrinsic viscosity. Common propylene copolymer have normally xylene soluble fractions with a rather low intrinsic viscosity, which is reflected in increased stickiness leading to reactor fouling.

The intrinsic viscosity is a measure of the capability of a polymer in solution to enhance the viscosity of said solution. The viscosity behavior of macromolccular substances in solution is one of the most frequently used approaches for characterization. The intrinsic viscosity number is defined as the limiting value of the specific viscosity/concentration ratio at zero concentration. It thus becomes necessary to find the viscosity at different concentrations and then extrapolate to zero concentration. The variation of the viscosity number with concentration depends on the type of molecule as well as the solvent. In general, the intrinsic viscosity of linear

macromolecular substances is related to the molecular weight or degree of polymerization. With macromoleculcs, viscosity number measurements provide a method for the rapid determination of molecular weight when the relationship between viscosity and molecular weight has been established. The intrinsic viscosity in the instant invention is measured according to DlN ISO 1628/1 , October 1999 (in Dccalin al 135 ⁰ C).

Accordingly the propylene copolymer according to this invention preferably fulfils the equation (2), more preferably the equation (2a), yet more preferably the equation (2b), still more preferably the equation (2c), still yet more preferably the equation

(2d), like the equation (2e)

IV (XS) [dl/g] - 0.3085 ^■ IV [dl/g] > -0.1 143 (2)

IV (XS) [dl/g] - 0.3085 ^■ IV [dl/g] > -0.1 101 (2a)

IV (XS) [dl/g] - 0.3085 ^■ IV [dl/g] > -0.0501 (2b) IV (XS) [dl/g] - 0.31 ^■ IV [dl/g] > -0.05 (2c)

IV (XS) [dl/g] - 0.3 ^■ IV [dl/g] > -0.2 (2d)

IV (XS) [dl/g] - 0.3 ^■ IV [dl/g] > -0.1 (2c) wherein

IV (XS) is the intrinsic viscosity of the xylene soluble fraction of the polypropylene copolymer measured according DIN ISO 1628/1 and

IV is the intrinsic viscosity of the total polypropylene copolymer measured according

DIN ISO 1628/1.

As can be seen from figure 7 the equations (2), (2a), (2b), (2c), (2d) and (2c), respectively define in a simple manner the benefit of the invention. The inventive propylene copolymers have a xylene soluble fraction with a significant higher intrinsic viscosity compared to the known propylene copolymers being state of the art. This positive property is reached independently from the comonomcr content present in the propylene copolymer of the instant invention.

- 1 !

Moreover the high intrinsic viscosity values of the xylene soluble fraction of the inventive propylene copolymers arc also reached in broad range of melt flow rate. This can be easily learned from figure 8. Thus it is preferred that the propylene copolymer of the instant invention fulfils the equation (3), more preferably the equation (3a), still more preferably the equation (3b), yet more preferably the equation (3 c)

IV (XS) [dl/g] + 0.0083 MFR [g/10min] > 0,601 (3)

IV (XS) [dl/g] + 0.0083 MFR [g/10min] > 0.621 (3a)

IV (XS) [dl/g] + 0.0083 MFR [g/10min] > 0.641 (3b) IV (XS) [dl/g] + 0.01 MFR [g/lOminj > 0.64 (3c) wherein

IV (XS) is the intrinsic viscosity of the xylene soluble fraction of said polypropylene copolymer measured according DIN ISO 1628/1, and

MFR is the melt flow rate measured according to ISO 1 133 at 230 ⁰ C and 2.16 kg load.

Additionally it is preferred that the xylene soluble fraction of the inventive propylene copolymer as defined herein has a intrinsic viscosity of at least 0.4 dl/g, more preferably of at least 0.5 dl/g. Moreover it is appreciated that the intrinsic viscosity of the total propylene copolymer reaches a certain value. Thus it is preferred that the intrinsic viscosity of the total propylene copolymer is at least 1.0 dl/g, more preferably at least 1.2 dl/g.

In a third embodiment of the present invention a propylene copolymer is provided comprising monomer units of propylene and at least one other α-oicfin as a comonomer, wherein

(a) the weight ratio of the α-olcfm to the sum of monomers present in said polypropylene copolymer (comonomer / (comonomer + propylene)) is at least 2.0 wt.-%,

(b) said propylene copolymer comprises a xylene soluble fraction (XS) of at least 2.0 wt.-%, and

(c) said polypropylene copolymer fulfils the equation 2

IV (XS) [dl/g] - 0.3085 ^■ IV [dl/g] > -0.1 143 (2) wherein

IV (XS) is the intrinsic viscosity of the xylene soluble fraction of said polypropylene copolymer measured according DIN ISO 1628/1 and IV is the intrinsic viscosity of the total polypropylene copolymer measured according DIN ISO 1628/1.

Surprisingly, it has been found that propylene copolymers with such characteristics have superior properties compared to the propylene copolymers known in the art. Especially the propylene copolymers of the instant invention have superior impact resistance and brittle behaviour compared to commercially available propylene copolymers (sec Figures 17, 18) Moreover the propylene copolymers keep over a broad range of comonomcr content at a high level their transparency in terms of haze (Figure 20). Also the melting and crystallization temperature of the inventive propylene copolymers are less influenced by the comonomcr content and kept at high level (see Figures 1 1 to 14). Thus the propylene copolymer combines the benefit of reduced stickiness, i.e. better proccssability, and enhanced mechanical properties for instance in terms of improved impact resistance.

The first requirement according to the third embodiment of the present invention is that the propylene copolymer comprises beside propylene a certain amount of comonomcr being an α-olefin. Preferred α-olefms are selected from the group consisting of ethylene, C^ α-olefin, C ₅ α-olcfin and Ce α-olefin to Cs α-olefin, more preferably selected from the group consisting of ethylene, 1-bulene, 1 -heptcne, 1- hcxcnc and 1-oclene, still more preferably selected from the group consisting of ethylene and C ₄ α-olcfin, yet more preferably selected from the group consisting of ethylene and 1 -butene, and most preferably ethylene. The propylene copolymer may

comprise mixtures of the above mentioned comonomcrs, however it is preferred that the propylene copolymer comprises only one species of α-olefin as a comonomer, In the most preferred embodiment the propylene copolymer comprises only propylene and ethylene.

The amount of comonomer present in the propylene copolymer must be at least 2.0 wt.-% to obtain the desired properties in particular with regard to the mechanical properties, like superior impact resistance. More precisely the weight ratio of the comonomer (being a α-olefin as defined above) to the sum of monomers present in said polypropylene copolymer (comonomer / (comonomer + propylene)) is at least 2.0 wt.-%, more preferably is at least 3,0 wl.-% and still more preferably is at least 5.0 wt. ~%. On the other hand the comonomer should be preferably not to high otherwise the polymer might loose its rigidity. Accordingly the weight ratio of the comonomer to the sum of monomers present in said polypropylene copolymer (comonomer / (comonomer + propylene)) shall preferably not exceed 30.0 wt.-%, more preferably not exceed 15.0 wt.-%, still more preferably not exceed 10,0 wt.-% and yet more preferably shall not exceed 8,0 wt.-%. Preferred ranges are 2.0 to 20.0 wt.-%, more preferred 2.0 to 12.0 wt.-%, yet more preferred 2.0 to 10.0 wl.-%, still more preferred 3.0 to 10,0 wt.-%, still yet more preferred 3.0 to 8,0 wt.-%, and most preferred 5.0 to 7.0 wt.-%. Accordingly it is preferred that the propylene copolymer according to this invention is a random propylene copolymer. The comonomer content can be determined with FT infrared spectroscopy, as described below in the example section.

Moreover it is required that the propylene copolymer has xylene solubles of some extent, i.e. of at least 2.0 wt.-%. Xylene solubles arc the part of the polymer soluble in cold xylene determined by dissolution in boiling xylene and letting the insoluble part crystallize from the cooling solution (for the method sec below in the experimental part). The xylene solubles fraction contains polymer chains of low stereo-regularity and is an indication for the amount of non-crystalline areas.

Preferably, the propylene copolymer has xylene solubles of more than 6.0 wl.-%. On the other hand, the amount of xylene solubles should not be too high since they represent a potential contamination risk. Accordingly it is preferred that the xylene solubles are not more than 40.0 wt.-%, still more preferably not more than 35.0 wt.~ % and yet more preferably not more than 20.0 wt.-%. In preferred embodiments the xylene solubles arc in the range of 5.0 to 40.0 wt.-%, more preferably in the range of 6.0 to 30.0 wt. -% and still more preferably in the range of 6.0 to 20.0 wt.-%.

As stated above it is required that the xylene soluble fraction of the inventive propylene copolymer is characterized by a rather high intrinsic viscosity. Common propylene copolymer have normally xylene soluble fractions with a rather low intrinsic viscosity, which is reflected in increased stickiness leading to reactor fouling.

The intrinsic viscosity is a measure of the capability of a polymer in solution to enhance the viscosity of said solution. The viscosity behavior of macromolecular substances in solution is one of the most frequently used approaches for characterization. The intrinsic viscosity number is defined as the limiting value of the specific viscosity/concentration ratio at zero concentration. It thus becomes necessary to find the viscosity at different concentrations and then extrapolate to zero concentration. The variation of the viscosity number with concentration depends on the type of molecule as well as the solvent. In general, the intrinsic viscosity of linear macromolecular substances is related to the molecular weight or degree of polymerization. With macromoleculcs, viscosity number measurements provide a method for the rapid determination of molecular weight when the relationship between viscosity and molecular weight has been established. The intrinsic viscosity in the instant invention is measured according to DIN ISO 1628/1 , October 1999 (in Dccalin at 135 ⁰ C).

Accordingly the propylene copolymer according to this invention fulfils the equation

(2), preferably the equation (2a), yet more preferably the equation (2b), still more preferably the equation (2c), still yet more preferably the equation (2d), like the equation (2e) IV (XS) [dl/g] - 0.3085 ^• IV [dl/g] > -0.1 143 (2)

IV (XS) [dl/g] - 0.3085 ^• IV [dl/g] > -0.1 101 (2a)

IV (XS) [dl/g] - 0.3085 ^■ IV [dl/g] > -0.0501 (2b)

IV (XS) [dl/g] - 0.31 ^• IV [dl/g] > -0.05 (2c)

IV (XS) [dl/g] - 0.3 ^■ IV [dl/g] > -0.2 (2d) IV (XS) [dl/g] - 0.3 ^■ IV [dl/g] > -0.1 (2c) wherein

IV (XS) is the intrinsic viscosity of the xylene soluble fraction of the polypropylene copolymer measured according DIN ISO 1628/1 and

IV is the intrinsic viscosity of the total polypropylene copolymer measured according DIN ISO 1628/1.

As can be seen from figure 7 the equations (2), (2a), (2b), (2c), (2d) and (2e), respectively define in a simple manner the benefit of the invention. The inventive propylene copolymers have a xylene soluble fraction with a significant higher intrinsic viscosity compared to the known propylene copolymers being state of the art. This positive property is reached independently from the comonomer content present in the propylene copolymer of the instant invention.

Moreover the high intrinsic viscosity values of the xylene soluble fraction of the inventive propylene copolymers arc also reached in broad range of melt flow rate. This can be easily learned from figure 8. Thus it is preferred that the propylene copolymer of the instant invention fulfils the equation (3), more preferably the equation (3a), still more preferably the equation (3b), yet more preferably the equation (3c) IV (XS) [dl/g] + 0.0083 MFR [g/I0min] > 0.601 (3)

IV (XS) [dl/g] H- 0.0083 MFR [g/10min] > 0.621 (3a) IV (XS) [dl/g] + 0.0083 MFR [g/10min] > 0.641 (3b) IV (XS) [dl/g] + 0.01 MFR [g/10min] > 0,64 (3c) wherein IV (XS) is the intrinsic viscosity of the xylene soluble fraction of said polypropylene copolymer measured according DlN ISO 1628/1, and

MFR is the melt flow rate measured according to ISO 1 133 at 230 ⁰ C and 2.16 kg load.

Additionally it is preferred that the xylene soluble fraction of the inventive propylene copolymer as defined herein has a intrinsic viscosity of at least 0.4 di/g, more preferably of at least 0.5 dl/g. Moreover it is appreciated that the intrinsic viscosity of the total propylene copolymer reaches a certain value. Thus it is preferred that the intrinsic viscosity of the total propylene copolymer is at least 1.0 dl/g, more preferably at least 1.2 dl/g.

Furthermore the propylene copolymer according to this invention is preferably further specified by its lamellar thickness distribution. The stepwise isothermal segregation technique (SIST) provides a possibility to determine the lamellar thickness distribution. The precise measuring method is specified in the example section (in particular the definition of the lamella thickness of each fraction and its melt enthalpy). Thereby rather high amounts (rather high melt enthalpy [J/g]) of polymer fractions crystallizing at high temperatures indicate a rather high amount of thick lamellae.

It has been recognized that the improved balance between the mechanical and process properties can be achieved with a propylene copolymer having a specific lamellar thickness distribution, i.e. a propylene copolymer comprising a fraction with a lamella thickness of more than 9,0 nm. More preferably the propylene copolymer comprises a fraction with a lamella thickness of more than 9.2 nm, still more

prefcrably of more than 9,5 nm. Preferred ranges for said fraction are from 9.0 to 12,0 nm, more preferred from 9,2 to 1 1.0 nm.

A further requirement of the above defined fraction is that it represents the largest fraction of all fractions, in particular compared to the fractions with a lamella thickness below 9.0 nm, of the propylene copolymer. Accordingly the propylene copolymer comprises a fraction with a lamella thickness of more than 9.0 nm (the other preferred values for the lamella thickness arc given above) having a higher melt enthalpy [J/g] as each lamella fraction with a lamella thickness below 9.0 nm. More preferably the fraction with a lamella thickness of more than 9.0 nm has melt enthalpy of more than 20.0 J/g, still more preferably of more than 21 .0 J/g. Concerning the fractions below 9,0 nm it is preferred that the they have a melt enthalpy of not more than 30.0 J/g. It is in particular preferred that the fractions with a lamella thickness in the range of 6.5 to 9.0 nm have a melt enthalpy in the range of 15.0 to 30.0 J/g.

The propylene copolymer according to this invention is further preferably defined by its isotactic sequence length distribution.

The measurement of isotactic sequence length distribution is performed in the instant invention by using the temperature rising elution fraction (TREF) technique (the exact description is given in the experimental part), which fractionates propylene copolymers according to the solubility differences, It has been clearly demonstrated for propylene polymers that the temperature rising elution fraction (TREF) technique fractionates the propylene polymer according to the longest crystallisablc sequences in the chain, which increases almost linearly with the elution temperature (P. Villc ct al., Polymer 42 (2001) 1953-1967). Hence the higher the maximum temperature the longer are the isotactic sequences. The results further showed that the temperature rising elution fraction (TREF) technique does not strictly fractionate polypropylene according to tacticity but according to the longest crystallisablc sequences in the

chain. The solubility of a polypropylene polymer chain hence is influenced only by the concentration and distribution of sterical defects. Insofar the temperature rising elution fraction (TREF) technique is an appropriate method to characterize the inventive propylene copolymer further.

Thus it is preferred that the propylene copolymer posses a distribution curve of the average isotactic chain length featured by at least two distinct maxima, i.e. the comonomer units are not equally distributed among the individual chains of the propylene copolymer. Accordingly it is preferred that the temperature rising elution fractionation (TREF) curve of the inventive propylene copolymer comprises at least two local maxima

(i) one absolute maximum over 100 ⁰ C, more preferably between 100 to

1 10 ⁰ C, and,

(U) one relative maximum between 50 and 85 ⁰ C, more preferably between 55 to 80 ⁰ C, and yet more preferably between 60 and 80 ⁰ C.

More preferably the area below the absolute maximum of that the temperature rising elution fractionation (TREF) function is in the range of 50 to 85 wt.-%, more preferably in the range of 50 to 80 wt.-% and yet more preferably in the range of 55 to 80 wt. ~%. With regard to the area below the relative maximum of the temperature rising elution fractionation (TREF) function as defined above it is preferred that it is in the range of 30 to 30 wt-%, more preferably in the range of 10 to 25 wt.-%.

In a fourth embodiment of the present invention a propylene copolymer is provided comprising monomer units of propylene and at least one other α-olefin as a comonomer, wherein

(a) the weight ratio of the α-olefin to the sum of monomers present in said polypropylene copolymer (comonomer / (comonomer + propylene)) is at least 2.0 wl.-%,

(b) said propylene copolymer comprises a xylene soluble fraction (XS) of at least 2,0 wt,-%, and

(c) said polypropylene copolymer fulfils the equation 3

IV (XS) [dl/g] + 0.0083 MFR [g/10min] > 0.601 (3) wherein

IV (XS) is the intrinsic viscosity of the xylene soluble fraction of said polypropylene copolymer measured according DlN ISO 1628/1 and MFR is the melt flow rate measured according to ISO 1 133 at 230 ⁰ C and 2.16 kg load.

Surprisingly, it has been found that propylene copolymers with such characteristics have superior properties compared to the propylene copolymers known in the art. Especially the propylene copolymers of the instant invention have superior impact resistance and brittle behaviour compared to commercially available propylene copolymers (see Figures 17, 18) Moreover the propylene copolymers keep over a broad range of comonomer content at a high level their transparency in terms of haze (Figure 20). Also the melting and crystallization temperature of the inventive propylene copolymers are less influenced by the comonomer content and kept at high level (sec Figures 1 1 to 14). Thus the propylene copolymer combines the benefit of reduced stickiness, i.e. better proccssability, and enhanced mechanical properties for instance in terms of improved impact resistance.

The first requirement according to the fourth embodiment of the present invention is that the propylene copolymer comprises beside propylene a certain amount of comonomer being an α-olefin. Preferred α-olefins are selected from the group consisting of ethylene, Q α-olcfm, Cs α-olcfin and C _f1 α~olcfin to Cs α-olefin, more preferably selected from the group consisting of ethylene, 1-butcne, 1-heptene, 1- hexene and 1-octcnc, still more preferably selected from the group consisting of ethylene and C ₄ α-olefin, yet more preferably selected from the group consisting of ethylene and 1-butcne, and most preferably ethylene. The propylene copolymer may

comprise mixtures of the above mentioned comonomers, however it is preferred that the propylene copolymer comprises only one species of α-olefin as a comonomcr. In the most preferred embodiment the propylene copolymer comprises only propylene and ethylene.

The amount of comonomcr present in the propylene copolymer must be at least 2.0 wt. -% to obtain the desired properties in particular with regard to the mechanical properties, like superior impact resistance. More precisely the weight ratio of the comonomer (being a α-olcfin as defined above) to the sum of monomers present in said polypropylene copolymer (comonomcr / (comonomer + propylene)) is at least 2,0 wt.-%, more preferably is at least 3.0 wt.-% and still more preferably is at least 5.0 wt.-%. On the other hand the comonomcr should be preferably not to high otherwise the polymer might loose its rigidity. Accordingly the weight ratio of the comonomer to the sum of monomers present in said polypropylene copolymer (comonomer / (comonomer + propylene)) shall preferably not exceed 30.0 wt.-%, more preferably not exceed 15.0 wt.-%, still more preferably not exceed 30.0 wt.-% and yet more preferably shall not exceed 8.0 wt-%. Preferred ranges arc 2.0 to 20.0 wt.-%, more preferred 2.0 to 12.0 wt.-%, yet more preferred 2.0 to 10.0 wt.-%, still more preferred 3.0 to 10.0 wt.-%, still yet more preferred 3.0 to 8.0 wt.-%, and most preferred 5.0 to 7.0 wt.-%. Accordingly it is preferred that the propylene copolymer according to this invention is a random propylene copolymer. The comonomer content can be determined with FT infrared spectroscopy, as described below in the example section.

Moreover it is required that the propylene copolymer has xylene solubles of some extent, i.e. of at least 2.0 wt.-%. Xylene solubles are the part of the polymer soluble in cold xylene determined by dissolution in boiling xylene and letting the insoluble part crystallize from the cooling solution (for the method sec below in the experimental part). The xylene solubles fraction contains polymer chains of low stereo-regularity and is an indication for the amount of non-crystalline areas.

Preferably, the propylene copolymer has xylene solubles of more than 6.0 wt.-%. On the other hand, the amount of xylene solubles should not be too high since they represent a potential contamination risk. Accordingly it is preferred that the xylene solubles are not more than 40.0 wt-%, still more preferably not more than 35.0 wt,- % and yet more preferably not more than 20.0 wt.~%. In preferred embodiments the xylene solubles are in the range of 5.0 to 40.0 wl.-%, more preferably in the range of 6.0 to 30.0 wt.-% and still more preferably in the range of 6.0 to 20.0 wt.-%.

As slated above it is required that the xylene soluble fraction of the inventive propylene copolymer is characterized by a rather high intrinsic viscosity. Common propylene copolymer have normally xylene soluble fractions with a rather low intrinsic viscosity, which is reflected in increased stickiness leading to reactor fouling.

The intrinsic viscosity is a measure of the capability of a polymer in solution to enhance the viscosity of said solution. The viscosity behavior of macromolccular substances in solution is one of the most frequently used approaches for characterization. The intrinsic viscosity number is defined as the limiting value of the specific viscosity/concentration ratio at zero concentration. It thus becomes necessary to find the viscosity at different concentrations and then extrapolate to zero concentration. The variation of the viscosity number with concentration depends on the type of molecule as well as the solvent. In general, the intrinsic viscosity of linear macromolecular substances is related to the molecular weight or degree of polymerization. With macromolecules, viscosity number measurements provide a method for the rapid determination of molecular weight when the relationship between viscosity and molecular weight has been established. The intrinsic viscosity in the instant invention is measured according to DIN ISO 1628/1 , October 1999 (in Decalin at 135 ⁰ C).

Morcover the inventive propylene copolymers shall not only have a xylene soluble fraction with rather high intrinsic viscosity values but said inventive propylene copolymers shall also obtainable in broad range of melt flow rate. Thus as stated above the propylene copolymer of the instant invention fulfils the equation (3), more preferably the equation (3a) still more preferably the equation (3b), yet more preferably the equation (3c)

IV (XS) [dl/g] + 0.0083 MFR [g/1 Omin] > 0.601 (3)

IV (XS) [dl/g] + 0.0083 MFR [g/1 Omin] > 0.621 (3a)

IV (XS) [dl/g] + 0.0083 MFR [g/10min] > 0.641 (3b) IV (XS) [dl/g] + 0.01 MFR [g/1 Omin] > 0.64 (3c) wherein

IV (XS) is the intrinsic viscosity of the xylene soluble fraction of said polypropylene copolymer measured according DIN ISO 1628/1 , and

MFR is the melt flow rate measured according to ISO 1 133 at 230 ⁰ C and 2.16 kg load.

Additionally it is appreciated that the propylene copolymer according to this invention preferably fulfils the equation (2), more preferably the equation (2a), yet more preferably the equation (2b), still more preferably the equation (2c), still yet more preferably the equation (2d), like the equation (2c)

IV (XS) [dl/g] - 0.3085 ^■ I V [dl/g] > -0.1 143 (2)

IV (XS) [dl/g] - 0.3085 ^■ IV [dl/g] > -0.1 101 (2a)

IV (XS) [dl/g] - 0.3085 ^■ IV [dl/g] > -0.0501 (2b)

IV (XS) [dl/g] - 0.31 ' IV [dl/g] > -0.05 (2c) IV (XS) [dl/g] - 0.3 ^■ IV [dl/g] > -0.2 (2d)

IV (XS) [dl/g] - 0.3 ^■ IV [dl/g] > -0.1 (2c) wherein

IV (XS) is the intrinsic viscosity of the xylene soluble fraction of the polypropylene copolymer measured according DlN ISO 1628/1 and

IV is the intrinsic viscosity of the total polypropylene copolymer measured according DlN lSO 1628/1.

As can be seen from figure 7 the equations (2), (2a), (2b), (2c), (2d) and (2c), respectively define in a simple manner the benefit of the invention. The inventive propylene copolymers have a xylene soluble fraction with a significant higher intrinsic viscosity compared to the known propylene copolymers being state of the art. This positive property is reached independently from the comonomcr content present in the propylene copolymer of the instant invention.

Additionally it is preferred that the xylene soluble fraction of the inventive propylene copolymer as defined herein has a intrinsic viscosity of at least 0.4 dl/g, more preferably of at least 0.5 dl/g. Moreover it is appreciated that the intrinsic viscosity of the total propylene copolymer reaches a certain value. Thus it is preferred that the intrinsic viscosity of the total propylene copolymer is at least 1.0 dl/g, more preferably at least 1.2 dl/g.

Furthermore the propylene copolymer according to this invention is preferably further specified by its lamellar thickness distribution, The stepwise isothermal segregation technique (SIST) provides a possibility to determine the lamellar thickness distribution. The precise measuring method is specified in the example section (in particular the definition of the lamella thickness of each fraction and its melt enthalpy). Thereby rather high amounts (rather high melt enthalpy [J/g]) of polymer fractions crystallizing at high temperatures indicate a rather high amount of thick lamellae.

Jt has been recognized that the improved balance between the mechanical and process properties can be achieved with a propylene copolymer having a specific lamellar thickness distribution, i.e. a propylene copolymer comprising a fraction with a lamella thickness of more than 9.0 nm. More preferably the propylene copolymer

compriscs a fraction with a lamella thickness of more than 9.2 ran, still more preferably of more than 9.5 nm. Preferred ranges for said fraction are from 9.0 to 12,0 nm, more preferred from 9.2 to 1 1.0 nm.

A further requirement of the above defined fraction is that it represents the largest fraction of all fractions, in particular compared to the fractions with a lamella thickness below 9,0 nm, of the propylene copolymer, Accordingly the propylene copolymer comprises a fraction with a lamella thickness of more than 9,0 nm (the other preferred values for the lamella thickness are given above) having a higher melt enthalpy [J/g] as each lamella fraction with a lamella thickness below 9,0 nm. More preferably the fraction with a lamella thickness of more than 9,0 nm has melt enthalpy of more than 20,0 J/g, still more preferably of more than 21 ,0 J/g. Concerning the fractions below 9.0 nm it is preferred that the they have a melt enthalpy of not more than 30.0 J/g. It is in particular preferred that the fractions with a lamella thickness in the range of 6.5 to 9.0 nm have a melt enthalpy in the range of 15.0 to 30.0 J/g.

The propylene copolymer according to this invention is further preferably defined by its isotactic sequence length distribution.

The measurement of isotactic sequence length distribution is performed in the instant invention by using the temperature rising clυtion fraction (TREF) technique (the exact description is given in the experimental part), which fractionates propylene copolymers according to the solubility differences. It has been clearly demonstrated for propylene polymers that the temperature rising clυtion fraction (TREF) technique fractionates the propylene polymer according to the longest crystallisablc sequences in the chain, which increases almost linearly with the elution temperature (P. Ville et al., Polymer 42 (2001) 1953-1967). Hence the higher the maximum temperature the longer are the isotactic sequences. The results further showed that the temperature rising elution fraction (TREF) technique does not strictly fractionate polypropylene

according to tacticity but according to the longest crystallisablc sequences in the chain. The solubility of a polypropylene polymer chain hence is influenced only by the concentration and distribution of stcrical defects. Insofar the temperature rising clution fraction (TREF) technique is an appropriate method to characterize the inventive propylene copolymer further.

Thus it is preferred that the propylene copolymer posses a distribution curve of the average isotactic chain length featured by at least two distinct maxima, i.e. the comonomer units arc not equally distributed among the individual chains of the propylene copolymer. Accordingly it is preferred that the temperature rising clution fractionation (TREF) curve of the inventive propylene copolymer comprises at least two local maxima

(i) one absolute maximum over 100 ⁰ C, more preferably between 100 to

1 10 ⁰ C, and, (ii) one relative maximum between 50 and 85 ⁰ C, more preferably between

55 to 80 ⁰ C, and yet more preferably between 60 and 80 ⁰ C.

More preferably the area below the absolute maximum of that the temperature rising elution fractionation (TREF) function is in the range of 50 to 85 wt.-%, more preferably in the range of 50 to 80 and yet more preferably in the range of 55 to 80 wt.-%. With regard to the area below the relative maximum of the temperature rising elution fractionation (TREF) function as defined above it is preferred that it is in the range of 10 to 30 wt.-%, more preferably in the range of 10 to 25 wt,-%.

The further features mentioned below apply to all embodiments described above, i.e. the first, second, third and the forth embodiment as defined above.

Preferably the propylene copolymer is not a wax. Accordingly, the propylene copolymer is not degraded, for instance by heating the polymer above 300 ⁰ C.

As stated above, the benefit of the present invention can be reached over a broad range of the molecular weight. Accordingly the melt flow rate (MFR) of propylene copolymer can vary over a broad spectrum. The melt flow rate (MFR) mainly depends on the average molecular weight. This is due to the fact that long molecules render the material a lower flow tendency than short molecules. An increase in molecular weight means a decrease in the MFR-value. The melt flow rate (MFR) is measured in g/10 min of the polymer discharged through a defined dye under specified temperature and pressure conditions and the measure of viscosity of the polymer which, in turn, for each type of polymer is mainly influenced by its molecular weight but also by its degree of branching. The melt flow rate measured under a load of 2.16 kg at 230 ⁰ C (ISO 1 133) is denoted as MFR ₂ . Accordingly, it is preferred that in the present invention the tcrpolymcr has an MFR ₂ in a range of 0.1 to 500.0 g/10 min, more preferably of 0.5 to 100.0 g/10 min, still more preferred of 1.0 to 80.0 g/10 min.

The molecular weight distribution (MWD) is expressed as the ratio of weight average molecular weight (M _w ) and number average molecular weight (M _n ). The number average molecular weight (M _n ) is an average molecular weight of a polymer expressed as the first moment of a plot of the number of molecules in each molecular weight range against the molecular weight. In effect, this is the total molecular weight of all molecules divided by the number of molecules. In turn, the weight average molecular weight (M _w ) is the first moment of a plot of the weight of polymer in each molecular weight range against molecular weight.

The number average molecular weight (M _n ) and the weight average molecular weight (Mw) as well as the molecular weight distribution (MWD) are determined by size exclusion chromatography (SEC) using Waters Alliance GPCV 2000 instrument with online viscometer. The oven temperature is 140 ⁰ C. Trichlorobcnzenc is used as a solvent (ISO 16014).

It is preferred that the propylene copolymer of the present invention has a weight average molecular weight (M _w ) from 10,000 to 2,000,000 g/mol, more preferably from 20,000 to 1 ,500,000 g/mol. It is especially preferred that propylene copolymer according to this invention has a weight average molecular weight (M _w ) of more than 50,000 g/mol like 60,000 g/mol. Accordingly, it is appreciated that the propylene copolymer according to this invention has an M _w of 55,000 to 2,000,000 g/mol, more preferably of 60,000 to 1 ,500,000 g/mol.

The number average molecular weight (M _n ) of the propylene copolymer is preferably in the range of 5,000 to 750,000 g/mo I, more preferably from 10,000 to 750,000 g/mol.

As a broad molecular weight distribution (MWD) improves the processability of the polypropylene the molecular weight distribution (MWD) is preferably up to 20.0, more preferably up to 10.0, still more preferably up to 8.0.

Moreover it is preferably desired that the propylene copolymer has a rather high melting point (T ₁₁₁ ) and crystallization temperature (Tαysi).

Thus the propylene copolymer preferably fulfils the equation (4), more preferably the equation (4a), still more preferably the equation (4b), yet more preferably the equation (4c)

T ₁₁₁ [ ⁰ C] + 5.29 ^■ comonomer [wt-%] < 178.5 (4)

T ₁₁₁ [ ⁰ C] + 5.00 ^■ comonomer [wt.-%] < 178.5 (4a) T ₁₁₁ [ ⁰ C] + 4.50 ^• comonomer [wt-%] < 178.5 (4b)

T ₁₁₁ [ ⁰ C] + 4.5 ^■ comonomer [wt-%] < 178.5 (4c) in case the comonomer content is equal or below 5.09 wt-% (5.1 wt-% for equation (4c)), or

thc propylene copolymer preferably fulfils the equation (5), more preferably the equation (5a), stil! more preferably the equation (5b), yet more preferably the equation (5c)

T ₁₁₁ [ ⁰ C] + 5.29 ^• comonomer [wt.-%] > 178.5 (5) T ₁₁₁ [ ⁰ C] + 5.00 ^• comonomer [wt.-%] > 178.5 (5a)

T ₁₁₁ [ ⁰ C] H- 4.50 ^■ comonomer [wt.-%] > 178.5 (5b)

T ₁₁₁ [ ⁰ C] + 4.5 ^■ comonomer [wt.-%] > 178.5 (5c) in case the comonomer content is more than 5.09 wt.-% (5.1 wt,-% for equation

(5c)), wherein

T ₁₁₁ is the melting temperature and comonomer is the weight ratio of the comonomer to the sum of monomers present in said polypropylene copolymer (comonomer / (comonomer + propylene)).

It is in particular preferred, that the melting point of the propylene copolymer is at least 147 ⁰ C (T ₁₁₁ ), more preferably at least 155°C.

Alternatively or additionally it is preferred that the propylene copolymer preferably fulfils the equation (6), more preferably the equation (6a), still more preferably the equation (6b), yet more preferably the equation (6c)

T _cys i [ ⁰ C] + 7.29 ^■ comonomer [wl.-%] < 139.5 (6)

T _c ysi [ ⁰ C] + 7.00 ^• comonomer [wt.-%] < 139.5 (6a)

T _cy si [ ⁰ C] + 6.50 ^■ comonomer [wl.-%] < 139.5 (6b)

Tc ₀ T _M [ ⁰ C] + 6.5 ^• comonomer [wt.-%] < 139.5 (6c) in case the comonomer content is equal or below 5.03 wt.-% (5.0 wt.-% for equation (6c)), or the propylene copolymer preferably fulfils the equation 7, more preferably the equation (7a), still more preferably the equation (7b), yet more preferably the equation (7c) T _ciysl [ ⁰ C] + 7.2857 - comonomer [wt.-%] > 139.5 (7)

T _CI ysi [°C] + 7.00 ^• comonomcr [wt.-%] > 139,5 (7a)

T _ciysl [ ⁰ C] + 6.50 ^■ comonomer [wl.-%] > 139.5 (7b)

Tc _ry si [ ⁰ C] + 6.5 ^■ comonomcr [wt-%] > 139.5 (7c) in case the comonomer content is more than 5.03 wt.-% (5.0 wt.-% for equation (7c)), wherein

T _cr y _s i is the crystallization temperature and comonomer is the weight ratio of the comonomer to the sum of monomers present in said polypropylene copolymer (comonomcr / (comonomcr + propylene)),

It is in particular preferred, that the crystallization temperature (T _cryat ) is at least

95 ⁰ C.

In addition it is appreciated that the inventive propylene copolymer has good optical properties. Thus it is preferred that propylene copolymer has a haze of not more than 40, still more preferred not more than 35 measured according to λSTM D 1003-92.

Preferably the above defined propylene copolymer is obtained in the presence of a specific external donor. It has been recognized that the improved propylene copolymer properties of the present invention can be in particular reached in case the propylene copolymer is produced in the presence of an ethoxy-substituted silane as external donor.

Preferably the external donor has the formula III RWmSi(OCH ₂ CH ₃ )Z (III) wherein

R' and R" are identical or different hydrocarbon residues, z is 2 or 3, preferably 2 m is 0 or 1 n is 0 or 1

with the proviso that n + m +z = 4.

Preferably R' and R" arc independently selected from the group consisting of linear aliphatic hydrocarbon group, branched aliphatic hydrocarbon group, cyclic aliphatic hydrocarbon group and aromatic group. It is in particular preferred that R' and R" are independently selected from the group consisting of methyl, ethyl, propyl, butyl, octyl, decanyl, i so -propyl, iso-butyl, iso-pentyl, tert, -butyl, tert.-amyl, ncopenlyl, cyciopentyl, cyclohcxyl, mcthylcyclopcnlyl and cycloheptyl. In a preferred embodiment the external donor has the formula IV wherein

R' and R" arc identical or different hydrocarbon residues, with the proviso that

(a) R ^! is a branched aliphatic hydrocarbon group or cyclic aliphatic hydrocarbon group, preferably selected from the group consisting of iso-propyl, iso-pentyl, tcrl.-butyl, tert.-amyl, neopentyl, cyciopentyl, cyclohcxyl, mcthylcyclopcntyl and cycloheptyl, and

(b) R" is selected from the group consisting of linear aliphatic hydrocarbon group, branched aliphatic hydrocarbon group and cyclic aliphatic hydrocarbon group, preferably selected from the group consisting of methyl, ethyl, propyl, butyl, octyl, decanyl, iso-propyl, iso-butyl, iso-pentyl, terl-butyl, tcrl.-amyl, neopentyl, cyciopentyl, cyclohexyl, methylcyclopcntyl and cycloheptyl.

Accordingly it is preferred that the external donor is selected from the group consisting of diisopropyldiethoxysilanc (DIPDES), cyclohexylmcthyldicthoxysilane (CHMDES) and dicyclopentadicnyldicthoxysilanc (DCPDES). The most preferred external donor is diisopropyldiethoxysilanc (DIPDES).

Even more preferred the inventive propylene copolymer has be produced in the presence of a specific catalyst system based on Ziegler-Natta. Thus the new propylene copolymer of the instant invention is in particular obtained by the following catalyst system and process as defined below, As the selection of the catalyst system may play a decisive role when tailoring propylene copolymers, in particular when producing those copolymers as stated above the present invention is also directed to the following catalyst system.

Accordingly the present invention provides a catalyst system comprising (a) a procatalyst composition comprising

(i) a transition metal compound of Group 4 to 6 of the Periodic table (IUPAC, Nomenclature of Inorganic Chemistry, 1989), (ii) MgCl ₂ and (iii) an internal donor, wherein (iv) said internal donor comprises a diaikylphthalate of formula

(H)

wherein R| and R ₂ are independently a C] to C ₄ alkyl like C| or C ₂ alkyl, i.e. methyl or ethyl, preferably R] and R ₂ are the same Ci to C ₄ aikyl residues like C] or C ₂ alky! residues, i.e. methyl or ethyl, and (b) an external donor being an ethoxy-substituted silane, preferably the external donor has the formula IV R'R"Si(OCH ₂ CH ₃ )2 (IV)

whercin

R' and R" arc identical or different hydrocarbon residues.

Preferably the inventive catalyst system as defined in the previous paragraph docs not comprise

(a) external donors having the formula (V)

R'R"Si(OCH ₃ ) ₂ (V) wherein

R' and R" arc identical or different hydrocarbon residues and/or

(b) external donors having the formula (VI) wherein

R'" is a hydrocarbon residue.

Accordingly in a preferred embodiment the catalyst system of the instant invention does not comprise propyllricthoxysilanc, vinyltriethoxysilanc and bcta- phenylmethyidicthoxysilane.

Il is in particular appreciated that the inventive catalyst system as defined in the instant invention comprises as an external donor only the external donor having the formula (IV) as defined above and in more detail beiow. Accordingly it is preferred that the catalyst system according to this invention is free of any further external donors and contains only an alkyl-diclhoxysilane derivative, in particular the alkyl- diethoxysilanc derivative of formula (IV) as defined in the instant invention.

Surprisingly it has been found that with the new catalyst system having the above defined properties propylene copolymers can be produced having superior impact resistance and brittle behaviour compared to commercially available propylene copolymers (sec Figures 17 and 18). Moreover the propylene copolymers produced

with the new catalyst system keep over a broad range of comonomcr content at a high level their transparency in terms of haze (Figure 20). Also the melting and crystallization temperature of the propylene copolymers obtained by the new catalyst system are less influenced by the comonomcr content and kept at high level (see Figures 1 1 to 14). Thus the new catalyst system enables to produce propylene copolymers that combine the benefit of reduced stickiness, i.e. better processabilily, and enhanced mechanical properties for instance in terms of improved impact resistance. Such propylene copolymers have been up to now not producible with catalyst systems known in the art (see also Figures 21 to 25). What can be in particular observed is that with the new catalyst system the incorporation of the comonomcr, in particular of ethylene, leads not to a significant reduction of the melting point whereas by the use of conventional catalyst systems the melting point decreases with the inserted amount of ethylene (from 152 ⁰ C at 5 wt.-% C2 to 144 ⁰ C at 6.5 wt.-% C2). Moreover it is additionally recognized that with the new catalyst system the intrinsic viscosity of the xylene soluble fraction of the propylene copolymers is on a very low level, not exceeding 0.6 dl/min up to 6 wt,-% C2.

As a first requirement the catalyst system must comprise a procatalyst composition comprising a transition metal compound of Group 4 to 6 of the Periodic table (IUPAC, Nomenclature of Inorganic Chemistry, 1989), magnesium chloride (MgCl ₂ ) and an internal donor.

The transition metal compound is preferably selected from the group consisting of titanium compound having an oxidation degree of 3 or 4, vanadium compound, chromium compound, zirconium compound, hafnium compound and rare earth metal compounds, more preferably selected from the group consisting of titanium compound, zirconium compound and hafnium compound, and most preferably the transition metal is titanium compound. Moreover the transition metal compounds arc in particular transition metal halides, such as transition metal chlorides. The titanium trichloride and titanium tetrachloride are particularly preferred.

Moreover as stated above the procalalyst composition must comprise an internal donor, which is chemically different to the external donor of the catalytic system, i.e. the internal donor must comprise a dialkylphthalatc of formula (II), wherein R| and R ₂ can be independently selected from a Cj to C ₄ alky], preferably R, and R ₂ arc the same, i.e. define the same Ci to C ₄ alkyl residue. The internal donor is defined by the fact that it is included in the mixture of the transition metal compound of Group 4 to 6 of the Periodic table (IUPAC, Nomenclature of Inorganic Chemistry, 1989) and MgCk (preferably in the presence of an alcohol) thereby reacting to the procataiysl composition, whereas the external donor is added (optionally together with the cocatalyst) to the mixture of the monomers and the procatalysl composition in the polymerisation process. Preferably the internal donor comprises a n-dialkylphthalatc of formula (II), wherein Ri and R ₂ can be independently selected from a Ci to C4 alkyl, preferably Ri and R ₂ arc the same, i.e. define the same Ci to C ₄ alkyl residue. Still more preferably the internal donor comprises n-dialkylphthalale of formula (II), wherein R| and R ₂ can be independently selected from a Ci and C ₂ alkyl, preferably R ₁ and R ₂ arc the same, i.e. define the same Ci or C ₂ alkyl residue. Still more preferably the internal donor comprises diethylphthalalc.

Of course the above defined and further below defined procalalysl composition is a solid, supported procalalyst composition.

Moreover it is preferred that the procalalyst composition contains not more than 2.5 wt. -% of the transition metal, preferably titanium. Still more preferably the procalalysl composition contains 1.7 to 2.5 wt.-% of the transition metal, preferably titanium. Additionally it is appreciated that the molar ratio internal donor/Mg of the procatalyst composition is between 0.03 and 0.08, still more preferably between 0.04 and 0.06, and/or its donor content is between 4 and 15 wt.-%, still more preferably between 6 and 12 wt.-% and yet more preferably between 6 to 10 wt.-%,

Furthcrmorc it is preferred that the internal donor is the result of a transcsterification of a dialkylphthalate of formula (I) with an alcohol. It is in particular preferred that the procatalyst composition is a procalalyst composition as produced in the patent applications WO 92/196351 (FI 88047), WO 92/19658 (FI 88048) and EP O 491 566 A2 (FI 86886), The content of these documents is herein included by reference.

Accordingly it is preferred that the procatalyst composition is prepared by bringing together (a) a transition metal compound of Group 4 to 6 of the Periodic table

(IUPAC, Nomenclature of Inorganic Chemistry, 1989), in particular a transition metal compound as defined above, preferably a titanium compound, more preferably titanium halidc like TiCU, (b) MgCI ₂ , (c) a C] to Ci alcohol, preferably a Ci to C2 alcohol, like methanol or cthanol, most preferably cthanol and (d) a dialkylphthalate of formula (1),

wherein Ri and R ₂ have more carbon atoms as said alcohol, preferably are independently at least a C5 alkyl, like at least a Cg alkyl, more preferably Ri and R ₂ arc the same and are at least a Cs alkyl, like at least a Cg alkyl, or preferably a n-dialkylphthalate of formula (I) wherein R] and R ₂ have more carbon atoms as said alcohol, preferably are independently at least a

C _$ n-alkyl, like at least a Cs n-alkyl, more preferably Rj and R ₂ are the same and are at least a C ₅ n-aikyi, like at least a Cg n-alkyl or more preferably dioctylphlhalale, like di-iso-octylphlhalatc or diethylhcxylphlhalale, yet more preferably dicthylhcxylphthalalc, wherein a transeterification between said alcohol and said dialkylphthalate of formula (I) has been carried out under suitable transestcrification conditions, i.e. at a temperature between 130 to 150 ⁰ C.

Among others the preferred dia Iky lphlha late of formula (1) for the above and further down described process for the manufacture of the procatalyst composition is selected from the group consisting of propyϊhcxyphthalate (PrHP), dioctylphlhalale (DOP), di-iso-decylphthalatc (DIDP), diundecylphthalale, dicthylhcxylphlhalatc and dilridccylphthalalc (DTDP). The most preferred dialkylphthalate is dioctyiphthalalc (DOP), like di-iso-octylphthalate or dJethylhexylphlhalalc, in particular dielhylhexylphthalatc.

Preferably at least 80 wt.-%, more preferably at least 90 wt-%, of the dialkylphthalate of formula (I) is transcsterified to the dialkylphthalate of formula (II) as defined above.

It is particular preferred that the procatalyst composition is prepared by

(a) contacting a spray crystallised or solidified adduct of the formula MgCl ₂ *nElOH, wherein n is 1 to 6, with TiCL _f to form a titanised carrier,

(b) adding to said lilaniscd carrier a. a dialkylphthalate of formula (I) with Ri and R ₂ being independently at least a C5 alkyl, like at least a Cg alkyl, or preferably

b. a dialkylphthalate of formula (I) with Ri and R2 being the same and being at least a C ₅ alkyl, like at least a Cg alkyl or more preferably c. a dialkylphthalate of formula (I) selected from the group consisting of 5 propylhexylphthalatc (PrHP), dioctylphthalate (DOP), di-iso- dccylphthalatc (DIDP), and ditridecylphthalate (DTDP), yet more preferably the dialkylphthalate of formula (I) is dioclylphthalatc (DOP), like di-iso-octylphthalate or diethylhexylphthalatc, in particular diethylhexylphthalatc, I O to form a first product

(c) subjecting said first product to suitable transcsterification conditions, i.e. at a temperature between 130 to 150 ⁰ C such that said cthanol is transcsterified with said ester groups of said dialkylphthalate of formula (ϊ) to form preferably at least 80 mol-%, more preferably 90 mol-%, most

15 preferably 95 mol.-%, of a dialkylphthalate of formula (II) with R| and R ₂ being -CH ₂ CH ₃₅ and

(d) recovering said transesterification product as the procatalyst composition.

λs a further requirement the external donor must be carefully selected. It has been 0 recognized that the improved propylene copolymer properties of the present invention can be only reached in case the procatalyst composition as defined above is treated with an ethoxy-substituted silane as external donor. Preferably the external donor has the formula III

R'nR"mSi(OCH ₂ CH ₃ )z (III) 5 wherein

R' and R" are identical or different hydrocarbon residues, z is 2 or 3, preferably 2 m is 0 or 1 n is 0 or 1 0 with the proviso that n + m +z = 4.

Preferably R' and R" are independently selected from the group consisting of linear aliphatic hydrocarbon group, branched aliphatic hydrocarbon group, cyclic aliphatic hydrocarbon group and aromatic group. It is in particular preferred that R' and R" are independently selected from the group consisting of methyl, ethyl, propyl, butyl, octyl, decanyl, iso-propyl, iso-butyl, iso-penlyl, tcrt. -butyl, tcrt.-amyl, neopcntyl, cyclopentyl, cyclohcxyl, methylcyclopcntyl and cycloheptyl. In a preferred embodiment the external donor has the formula IV

R'R"Si(OCH ₂ CH ₃ ) ₂ (IV) wherein

R' and R" arc identical or different hydrocarbon residues, with the proviso that

(a) R' is a branched aliphatic hydrocarbon group or cyclic aliphatic hydrocarbon group, preferably selected from the group consisting of iso-propyl, iso-pcntyl, tcrt. -butyl, tert.-amyl, ncopcntyl, cyclopentyl, cyclohcxyl, mcthylcyclopenlyl and cycloheptyl, and

(b) R" is selected from the group consisting of linear aliphatic hydrocarbon group, branched aliphatic hydrocarbon group and cyclic aliphatic hydrocarbon group, preferably selected from the group consisting of methyl, ethyl, propyl, butyl, octyl, decanyl, iso-propyl, iso-butyl, iso-pcntyl, tert. -butyl, tert.-amyl, ncopentyl, cyclopentyl, cyclohcxyl, mcthylcyclopentyl and cycloheptyl.

Accordingly it is preferred that the external donor is selected from the group consisting of di-iso-propyldiethoxysilane (DIPDES), cyclohexylmcthyldiethoxysilanc (CFIMDES) and dicyclopcntadicnyldiethoxysilane (DCPDES). The most preferred external donor is di-iso-propyldicthoxysilanc (DIPDES)

Morcovcr the catalyst system may comprise a cocatalyst. Preferred cocatalysts arc organoaluminum compounds. Accordingly it is preferred to selected the cocatalyst from the group consisting of trialkylaluminium, like tricthylalυminium (TEA), dialkyl aluminium chloride and alkyl aluminium sesquichloride.

Especially good results are achieved with a catalyst system comprising

(a) a procatalyst composition being produced as defined in the patent applications WO 92/196351 (FI 88047), WO 92/19658 (FI 88048) and EP 0 491 566 A2 (FI 86886) (b) an external donor being an cthoxy- substituted silanc and

(c) optionally a cocatalyst.

Thus it is preferred that the catalyst system comprises

(a) a procatalyst composition comprising titanium, magnesium, chlorine and internal donor, wherein said internal donor comprises

(i) a dialkylphthalatc of formula (II),

wherein Ri and R2 are independently selected from a Ci to C4 alkyl, preferably Rj and R ₂ arc the same, i.e. define the same Ci to Ci alkyl residue, or preferably (ii) a n-dialkylphthalate of formula (II), wherein Ri and R ₂ can be independently selected from a C _\ to C ₄ n-alkyl, preferably Ri and R ₂ arc the same, i.e. define the same Ci to Q n-alkyl residue or more preferably

(iii) a n-dialkylphthalate of formula (II), wherein Ri and R ₂ can be independently selected from a Cj and C ₂ alkyl, preferably Ri and R ₂ arc the same, i.e. have the same Ci or C ₂ alky! residue, or still more preferably (iv) dicthylphthalate

(b) an external donor

(i) as defined by formula Hl, wherein R' and R" are preferably independently selected from the group consisting of linear aliphatic hydrocarbon group, branched aliphatic hydrocarbon group, cyclic aliphatic hydrocarbon group and aromatic group, more preferably independently selected from the group consisting of methyl, ethyl, propyl, butyl, octyl, decanyl, iso- propyl, iso-butyl, iso-pcntyl, tert. -butyl, tcrl.-amyl, neopentyl, cyclopentyl, cyclohcxyl, mcthylcyclopcntyl and cycloheptyl, or more preferably

(ii) as defined by formula IV (and the definition of R' and R" thereto) or still more preferably

(iii) being selected from the group consisting of di-iso- propyldiethoxysilanc (DIPDES), cyclohexylmethyldiethoxysilane (CHMDES) and dicyclopentadicnyldicthoxysilane (DCPDES) or yet more preferably

(iv) being di-iso-propyldiethoxysilanc (DIPDES), and

(c) optionally a cocatalyst selected from the group consisting of trialkylaluminium, like lricthylaluminium (TEA), dialkyl aluminium chloride and alkyl aluminium scsquichloride.

The catalyst system as defined in the previous paragraph comprises in particular as an external donor only the external donor as defined under item (b). Accordingly it is preferred that the catalyst system according to this invention is free of any further

external donors and contains only an alkyl-dicthoxysilane derivative, in particular the alkyl-dicthoxysilane derivative as defined in item (b) of the previous paragraph.

Moreover the present invention is directed to the manufacture of the catalyst system wherein in first step the procatalyst composition is produced and subsequently in a second step the external donor and optionally the cocalalyst is added. The procatalysl composition is preferably produced as defined in the in the patent applications WO 92/196351 (Fl 88047), WO 92/19658 (Fl 88048) and EP O 491 566 A2 (FI 86886). The content of these documents is herein included by reference. Accordingly it is in particular preferred that the procatalyst compostion is produced as defined above.

The propylene copolymer as defined in the instant invention above is preferably produced in the presence of a catalyst system as defined above. Thereby the polymerization may a single- or multistage process polymerization of propylene and comonomer such as bulk polymerization, gas phase polymerization, slurry polymerization, solution polymerization or combinations thereof using the above defined catalyst system. Preferably the process comprises also a prcpolymcrization with a catalyst system of the instant invention. Preferably the propylene copolymer is produced in loop reactors or in a combination of loop and gas phase reactor. Those processes arc well known to one skilled in the art.

A slurry reactor designates any reactor, such as a continuous or simple batch stirred tank reactor or loop reactor, operating in bulk or slurry and in which the polymer forms in particulate form. "Bulk" means a polymerization in reaction medium that comprises at least 60 wt-% monomer. According to a preferred embodiment the slurry reactor comprises a bulk loop reactor. This alternative is particularly suitable for producing bimodal propylene copolymer. By carrying out the polymerization in the different polymerization reactors in the presence of different amounts of hydrogen, the MWD of the product can be broadened and its mechanical properties

and processability improved. It is also possible to use several reactors of each type, e.g. one loop reactor and two or three gas phase reactors or two loops and one gas phase reactor, in series.

"Gas phase reactor" means any mechanically mixed or fluid bed reactor. Preferably the gas phase reactor comprises a mechanically agitated fluid bed reactor with gas velocities of at least 0.2 m/scc.

The particularly preferred embodiment of the invention comprises carrying out the polymerization in a process comprising loop and gas phase reactors in a cascade where the loop reactor operates in liquid propylene and at high polymerization temperatures. The second polymerization step is made in gas phase rcactor(s) in order to broaden the molar mass distribution of the propylene copolymer.

Considering the detailed information in this description, the following embodiments arc especially preferred:

10001] Propylene copolymer comprising monomer units of propylene and at least one other α-olefin as a co monomer, wherein (a) the weight ratio of the comonomer to the sum of monomers present in said polypropylene copolymer

(comonomcr/(comonomer + propylene)) is at least 2.0 wt.-%, (b) said propylene copolymer comprises a fraction having a lamella thickness of more than 9.0 ran, (c) said fraction with a lamella thickness of more than 9.0 nm has a higher melt enthalpy [J/g] as each fraction with a lamella thickness below 9.0 nm, and

(d) said fractions arc determined by stepwise isothermal segregation technique (SIST).

[0002] A polypropylene copolymer comprising monomer units of propylene and at least one other α-oleiϊn as a comonomcr, wherein

(a) the weight ratio of the comonomer to the sum of monomers present in said polypropylene copolymer (comonomcr/tcomonomer + propylene)) is at least 2.0 wt.-%, and

(b) the temperature rising elυtion fractionation (TREF) curve of said propylene copolymer comprises at least two local maxima

(v) one absolute maximum over 100 ⁰ C, and (vi) one relative maximum between 50 and 80 ⁰ C. [0003] A polypropylene copolymer comprising monomer units of propylene and at least one other α-olefin as a comonomer, wherein (a) the weight ratio of the comonomcr to the sum of monomers present in said polypropylene copolymer

(comonomcr/(comonomcr + propylene)) is at least 2.0 wl.-%, (b) said propylene copolymer comprises a xylene soluble fraction (XS) of at least 2.0 wt.-%, and

(c) said polypropylene copolymer fulfils the equation 2

IV (XS) [dl/g] - 0.3085 ^■ I V [dl/g] > -0.1 343 (2) wherein IV (XS) is the intrinsic viscosity of the xylene soluble fraction of said polypropylene copolymer measured according DIN ISO 1628/1 and

IV is the intrinsic viscosity of the total polypropylene copolymer measured according DIN ISO 1628/1. [0004] A polypropylene copolymer comprising monomer units of propylene and at least one other α-olcfin as a comonomcr, wherein (a) the weight ratio of the comonomer to the sum of monomers present in said polypropylene copolymer (comonomcr/(cornonomcr + propylene)) is at least 2.0 wt.-%,

(b) said propylene copolymer comprises a xylene soluble fraction (XS) of at least 2.0 wt.-%, and

(c) said polypropylene copolymer fulfils the equation 3

IV (XS) [dl/g] + 0.0083 MFR [g/10min] > 0.601 (3) wherein

IV (XS) is the intrinsic viscosity of the xylene soluble fraction of said polypropylene copolymer measured according DIN ISO 1628/1. and

MFR is the melt flow rate measured according to ISO 1 133 at 230 ⁰ C and 2.16 kg load.

[0005] A polypropylene copolymer according to [0001], wherein

(a) the temperature rising elution fractionation (TREF) function of said propylene copolymer comprises at least two local maxima

(v) one absolute maximum over 100 ⁰ C, and (vi) one relative maximum between 50 and 80 ⁰ C, and/or

(b) said propylene copolymer

(i) comprises a xylene soluble fraction (XS) of at least 2.0 wt.-%, and (ii) said propylene copolymer fulfils additionally the equation 2 and/or 3.

[0006] A polypropylene copolymer according to [θ002], wherein (a) said propylene copolymer comprises

(i) a fraction having a lamella thickness of more than 9.0 nm, (ii) said fraction has a higher melt enthalpy [J/g] as each fraction with a lamella thickness below 9.0 nm, (vii) said fractions are determined by stepwise isothermal segregation technique (SIST), and and/or (b) said propylene copolymer

(i) comprises a xylene soluble fraction (XS) of at least 2.0 wt.-%, and (U) said propylene copolymer fulfils additionally the equation 2 and/or 3. [0007] A polypropylene copolymer according to [0003], wherein

(a) said propylene copolymer comprises

(i) a fraction having a lamella thickness of more than 9.0 nm, (ii) said fraction has a higher melt enthalpy [J/g] as each fraction with a lamella thickness below 9.0 nm, (vii) said fractions arc determined by stepwise isothermal segregation technique (SlST), and and/or

(b) the temperature rising elution fractionation (TREF) function of said propylene copolymer comprises at least two local maxima (i) one absolute maximum over 100 ⁰ C, and

(ii) one relative maximum between 50 and 80 ⁰ C, and/or

(c) said propylene copolymer fulfils additionally the equation 3. [0008} A polypropylene copolymer according to [0004], wherein (a) said propylene copolymer comprises

(i) a fraction having a lamella thickness of more than 9,0 nm, (ii) said fraction has a higher melt enthalpy [J/g] as each fraction with a lamella thickness below 9.0 nm, (iii) said fractions arc determined by stepwise isothermal segregation technique (SlST), and and/or

(b) the temperature rising elution fractionation (TREF) function of said propylene copolymer comprises at least two local maxima (ii) one absolute maximum over 100 ⁰ C, and (ii) one relative maximum between 50 and 80 ⁰ C,

and/or

(c) said propylene copolymer fulfils additionally the equation 2.

[0009] A polypropylene copolymer according to any one of the preceding paragraphs JOOOl] to [0008], wherein the α-olcfin is ethylene. [0010] A polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0009], wherein the weight ratio of the α-olcfin to the sum of monomers present in said polypropylene copolymer (α- olcfin/(α~olefm + propylene)) is in the range of 2.0 to 10.0 wt-%.

[0011] A polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0010], wherein the xylene soluble fraction (XS) is in the range of 2.0 to 20.0 wt-%.

[0012] A polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0011], wherein the fraction having a lamella thickness of more than 9.0 nm has a melt enthalpy of more than 20 J/g. [0013] A polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0012], wherein each fraction having a lamella thickness below 9.0 nm has a melt enthalpy of not more than 30 J/g.

[0θϊ4] A polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0013], wherein each fraction having a lamella thickness in the range of 6.5 to 9.0 nm has a melt enthalpy in the range of

15 to 30 J/g.

[0015] A polypropylene copolymer according to any one of the preceding paragraphs [0001 ] to [0014], wherein the area below the absolute maximum of the temperature rising elution fractionation (TREF) function is in the range 50 to 85 wl.-%.

[0016] A polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0015], wherein the area below the relative maximum between 50 and 80 ⁰ C of the temperature rising elution fractionation (TREF) curve is in the range 10 to 30 wt.-%.

[0017] A polypropylene copolymer according to any one of the preceding paragraphs [00θ1] to [0θ16], wherein the absolute maximum of the temperature rising elυtion fractionation (TREF) curve is in the range of over 100 to 1 10 ⁰ C. [0018] A polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0017], wherein said polypropylene copolymer fulfils the equation 2a

IV (XS) [dl/g] - 0.3085 ^• IV [dl/g] > -0.1 101 (2a).

[0019] A polypropylene copolymer according Io any one of the preceding paragraphs [0001] to [0018], wherein said polypropylene copolymer fulfils the equation 3a

IV (XS) [dl/g] + 0.0083 MFR > 0.601 (3a). |0020] A polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0019], wherein the total polypropylene copolymer has intrinsic viscosity measured according DIN ISO 1628/1 of at least

1.1 dl/g. [0021 ] A polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0020], wherein the intrinsic viscosity of the xylene soluble fraction of said polypropylene copolymer has intrinsic viscosity measured according DIN ISO 1628/1 of at least 0.4 dl/g.

[0022] A polypropylene copolymer according to any one of the preceding paragraphs [0001 J to [0021 ], wherein said polypropylene copolymer has a melt flow rale (MFR) measured according to ISO 1 133 at 230 ⁰ C and 2,16 kg load in the range of 0.1 Io 500 g/10min. [0023] A polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0022], wherein (i) said polypropylene copolymer fulfils the equation 4

T _1n [ ⁰ C] + 5.29 ^■ comonomcr [wt.-%] < 178.5 (4) in case the comonomer content is equal or below 5.09 wt.-%, or (ii) said polypropylene copolymer fulfils the equation 5

T ₁₁₁ [ ⁰ C] + 5.29 ^• comonomer [wl.-%] > 178.5 (5) in case the comonomer content is more than 5.09 wt,-%, wherein

T _n , is the melting temperature and "comonomer" is the weight ratio of the comonomer to the sum of monomers present in said polypropylene copolymer (comonomer / (comonomer + propylene)). [0024] A polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0023], wherein (i) said polypropylene copolymer fulfils the equation 6

Toys [ ⁰ C] + 7.29 ^• comonomer [wl.-%] < 139.5 (6) in case the comonomer content is equal or below 5.03 wt.-%, or (ii) said polypropylene copolymer fulfils the equation 7

T _C!ysl [ ⁰ C] H- 7.2857 ^• comonomer [wt.-%] > 139.5 (7) in case the comonomer content is more than 5.03 wt.-%, wherein

Tci-yst is the crystallization temperature and "comonomer" is the weight ratio of the comonomer to the sum of monomers present in said polypropylene copolymer (comonomer / (comonomer + propylene)).

[0025] A polypropylene copolymer according to any one of the preceding paragraphs [000ϊ ] to [0024], wherein said polypropylene copolymer has a haze below 35 % measured according to ASTM D 1003-92. [0026] A polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0025], wherein said polypropylene copolymer has been produced in the presence of an cthoxy-substiluted silane as external donor, preferably in the presence of an external donor selected from the group consisting of diisopropyldiethoxysilanc (DIPDES), cyclohexylmethyldicthoxysilane (CHMDES) and dicyclopentadienyldiethoxysilane (DCPDES).

[0027] A polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0026], wherein said polypropylene copolymer has been produced in the presence of a catalyst system according to any one of the claims 28 lo 30. [0028] Catalyst system comprising

(a) a procatalyst composition comprising

(i) a transition metal compound of Group 4 to 6 of the Periodic table (IUPAC, Nomenclature of Inorganic Chemistry, 1989), (ii) MgCl ₂ and (iii) an internal donor, wherein

(iv) said internal donor comprises an dialkylphthalatc of formula

(H)

wherein Ri and R. ₂ arc independently a Ci to C^ alkyl and

(b) an external donor having the formula IV

R'R"Si(OCII ₂ CII ₃ )2 (IV) wherein

R' and R" arc identical or different hydrocarbon residues. [0029] Catalyst system according to paragraph [0028], wherein the external donor is selected from the group consisting of diisopropyldiethoxysilanc (DIPDES) ₅ cyclohcxylmcthyldiethoxysilanc (CHMDES) and dicyclopentadicnyldicthoxysilane (DCPDES).

[θθ30] Catalyst system according to paragraph [0028] or [0029], wherein the dialkylphthalate of formula (II) is a n-dialkylphthalate of formula (II).

[0031 J Use of the donor elhoxy-subslitutcd silanc for the manufacture of a polypropylene copolymer, [0032] Use according to paragraph [0031], wherein the donor is selected from the group consisting of diisopropyldiethoxysilanc (DIPDES), cyclohcxylmcthyldiclhoxysilanc (CHMDES) and dicyclopcnladicnyldiethoxysilanc (DCPDES). [0033] Use according to paragraph [0031] or [0032], wherein the polypropylene copolymer is a copolymer according to any one of the preceding paragraphs [0001] to [0027]. [0034] Process of the polypropylene copolymer according to any one of the preceding paragraphs [0001] to [0027], wherein said polypropylene copolymer has been produced in the presence of a donor as defined in the paragraph [0031 ] or paragraph [0032],

The present invention will now be described in further detail by the examples provided below.

EXAMPLES

1. Definitions/Measuring Methods The following definitions of terms and determination methods apply for the above general description of the invention as well as to the below examples unless otherwise defined.

Number average molecular weight (M _n ), weight average molecular weight (M _w ) and molecular weight distribution (MWD) are determined by size exclusion chromatography (SEC) using Waters Alliance GPCV 2000 instrument with online viscometer. The oven temperature is 140 ⁰ C. Trichlorobenzene is used as a solvent (ISO 16014).

MFR ₂ is measured according io ISO 1 133 (230 ⁰ C ₅ 2.16 kg load).

Comonomer content is measured with Fourier transform infrared spectroscopy (FTlR) calibrated with ' ³ C-NMR. When measuring the ethylene content in polypropylene, a thin film of the sample (thickness about 250 mm) was prepared by hot-pressing. The area of-CHb- absorption peak (800-650 cm ^"1 ) was measured with Perkin Elmer FTIR 1600 spectrometer. The method was calibrated by ethylene content data measured by ¹³ C-NMR.

Melting temperature Tm, crystallization temperature Tc, and the degree of crystallinity is measured with Mettler TA820 differential scanning calorimctry (DSC) on 5-10 mg samples. Both crystallization and melting curves were obtained during 10 °C/min cooling and heating scans between 30 ⁰ C and 225 ⁰ C. Melting and crystallization temperatures were taken as the peaks of cndotherms and exolhcrms. Also the melt- and crystallization enthalpy (Hm and Hc) were measured by the DSC method according to ISO 1 1357-3.

Haze is determined by ASTM Dl 003-92.

Intrinsic viscosity is measured according to DlN ISO 1628/1 , October 1999 (in Decalin at 135 ⁰ C).

The xylene solubles (XS, wt.-%): Analysis according to the known method: 2.0 g of polymer is dissolved in 250 ml p-xylcne at 135°C under agitation. After 30±2 minutes the solution is allowed to cool for 35 minutes at ambient temperature (21 ⁰ C) and then allowed to settle for 30 minutes at 25±0.5°C. The solution is filtered and evaporated in nitrogen flow and the residue dried under vacuum at 90 ⁰ C until constant weight is reached,

XS% = (100 x mi x Vo) / (m ₀ x vι), wherein mo = initial polymer amount (g) m i = weight of residue (g)

V ₀ = initial volume (ml)

Vi = volume of analyzed sample (ml)

Stepwise Isothermal Segregation Technique (SIST): The isothermal crystallisation for SIST analysis was performed in a Mettler TA820 DSC on 3+0.5 mg samples at decreasing temperatures between 200 ⁰ C and 105 ⁰ C. The samples were melted at 225 ⁰ C for 5 min, then cooled with 80 °C/min to 345 ⁰ C held for 2 hours at 145 ⁰ C, then cooled with 80 °C/min to 135 ⁰ C held for 2 hours at 135 ⁰ C, then cooled with 80 °C/min to 125 ⁰ C held for 2 hours at 125 ⁰ C, then cooled with 80 °C/min to 1 15 ⁰ C held for 2 hours at 1 15 ⁰ C,

then cooled with 80 °C/min to 105 ⁰ C held for 2 hours at 105 ⁰ C. then cooled down to - 10 ⁰ C with maximal cooling rate by a compression- cooling unit.

The melting curve is obtained by heating the cooled sample at a heating rate of 10°C/min up to 200 ⁰ C. All measurements were performed in a nitrogen atmosphere.

The minima of the melting curve (heat flow (cndo) downwards as a function of temperature; sec figures 3 and 4), i.e, the absolute minimum and the other relative minima (includes also shoulders), arc converted in the respective lamella thickness according to Thomson-Gibbs equation (Eq 1.)

wherein j/m ² , L is the lamella thickness and T _n , is the measured temperature (K). Such obtained lamella thicknesses define the fractions of each polymer sample (compare table 4).

The melt enthalpy [J/g] of each fraction of the polymer sample as defined above is obtained as follows: In general the melt enthalpy is calculated from the quotient of the heat flow volume and initial weight of the sample. The heat flow volume is recorded as function of temperature, i.e. the melting curve (see figures 3 and 4). The area above each minimum (includes also shoulders) of the melting curve represents its melt enthalpy. The integration limits for each area to be calculated are defined by relative maxima (includes also shoulders) and by the intersection points of the base line with the melting curve, in the direct neighborhood of each minimum of the melting curve.

The maxima, minima, shoulders of the melting curve as well as the areas are determined as known from DSC-cυrves.

Accordingly the relative maxima may be mathematically understood, i.e. a point x is a relative maximum of a function/ if there exists some ι: > 0 such that/fx y >f(x) for all λ' with \x-x ^* \ < ε. Furthermore, in case of shoulders, the first derivative of the function (the measured melting curve) must lead to a relative maximum at the relative maximum of said function. Excluded arc those inflection points that are located between two relative extrema.

Flexural moduϊus is measured according to ISO 178

Charpy impact strength is measured according ISO 179 at 23 °C and ISO 179-2 in the temperature range of 0 - 20 ⁰ C.

Temperature Rising Elution Fractionation (TREF):

The chemical composition distribution was determined by analytical Temperature Rising Elution Fractionation (a-TREF) as described in J.B.P. Soares, A.E. Hamiclcc; Temperature rising elution fractionation of linear polyolefins; Polymer 1995, 36 (8), 1639- 1654 and Soares, J. B. P., Fractionation, In: Encyclopedia Of Polymer Science and Technology, John Wiley & Sons, New York, pp. 75-131 , Vol. 10, 2001. The separation of the polymer in a-TREF is according to crystallinity. The TREF profiles were generated using a CRYSTAF-TREF 200+ instrument manufactured by PolymerChar S. A. (Valencia, Spain). The experimental procedure, as described in N. Aust, M. Gahleitner, K. Rcichelt, B. Raninger; Optimization of run parameters of temperature-rising elision fractionation with the aid of a factorial design experiment; Polymer Testing 2006, 25 (7), 896-903 was as follows: In the dissolution step, the polymer sample was dissolved in 1,2,4-trichlorobenzene (TCB ₅ 2 to 4 mg/mL, stabilized with 300 mg/L 2,6-Di tcrt butyl-4-methyl-phenol) in one of the vessels at a concentration of 4 mg/mL at 160 ⁰ C for 90 min. The sample

was then loaded into the TREF column (7.8 ram inner diameter, 15 cm length, packed with stainless steal shots as inert support), and held at 1 10 ⁰ C for 30 min for stabilization. The polymer sample was crystallized and precipitated onto the support inside the TREF column by a slow reduction of the temperature to 30 ⁰ C under a constant cooling rate (0.1 °C/min). The column temperature was kept at 30 ⁰ C for 25 min for stabilization before the elution step started. In the clution step, a solvent (TCB) flowed through the column at a constant flow rate of 0.5 mL/min while the temperature in the column was first held for 10 min at 30 °C to measure the remaining soluble fraction followed by slowly increasing the temperature to 130 ⁰ C at a constant heating rate (0.5 °C/min). The concentration of the polymer being elutcd was measured during the whole elution step with an infrared detector (measuring the C-H absorption at 3.5 microns wavelength) and recorded together with the temperature in the column oven as a function of lime.

The concentration signal was plotted as a function of the elution temperature (TREF profile). For convenience the under isothermal conditions (30 ⁰ C, 10 min) measured soluble fraction was added Io this plot by converting the time into temperature using the constant heating rate of 0.5 °C/min. In the TREF calculation software (by Polymer Char, version 07a) the concentration plot (TREF profile) was normalized including the soluble fraction.

EXAMPLES

Example 1: DϊPDES; MFR IO g/10 min ; C2 content 6.5 wt-% (Inventive) The propylene polymers used for the present invention were prepared according to the following procedure: Raw Materials:

Hexane dried over molecular sieve (3/ 10A) TEAL: 93 % from Sigma-Aldrich

Donor: Diisopropyidiethoxisilane ex Wackcr Chcmic (Manufacture of the donor is described in DE 38 21 483 Al)

N ₂ : supplier AGA, quality 5.0; purification with catalyst BASF R031 3 , catalyst G 132 (CuO/ZNO/C), molecular sieves (3/10A) and P ₂ O ₅ . Hydrogen: supplier AGA ₁ quality 6.0 Propylene: supplier Borcalis - Ethylene: supplier Air Liquide 3.5

The catalyst Polylrack 8502 is commercially available from Grace. Sandostab P-EPQ is an antioxidant and commercially available from Clariant Millad 3988 is a nucleating agent and commercially available from Milliken Irganox B215 is a blend of antioxidants, commercially available from Ciba - Calziumstearat S is an acid scavenger and commercially available from Faci.

Ionol CP is an antioxidant and commercially available from Dcgussa. The monomers used were additionally purified via BASF catalyst R3-1 1 (Cu), GIRDLER catalyst (CuO/ZnO) and molecular sieves 4 and 10 A. Preparation: A 20 1 autoclave reactor has been purified by mechanical cleaning, washing with hexane and heating under vacuum/N ₂ cycles at 160 ⁰ C. After testing for leaks with 30 bar N ₂ over night the reactor has been vacuumed and filled with 5350 g propylene by weighing and 18 nl H ₂ by pressure monitoring from a 50 1 steel cylinder. 35 mg of Polytrack 8502-catalyst are activated for 10 minutes with a mixture of Triclhylalυminium (TEAl; solution in hexane 1 mol/1) and Di-iso-

propyldiethoxysilanc as donor (0.3 mo 1/1 in hcxanc) - in a molar ratio of 10 after a contact time of 5 min - and 10 ml hexane in a catalyst feeder. The molar ratio of TEAl and Ti of catalyst is 250. After activation the catalyst is spilled with 250 g propylene into the stirred reactor with a temperature of 23 ⁰ C, Stirring speed is hold at 250 rpm. After 6 min prepolymcrisation at 23 ⁰ C temperature is increased to 70 ⁰ C in about 16 min. After holding that temperature for 1 hour and feeding constantly 1968mln/min ethylene into the reactor polymerisation is stopped by flashing propylene and cooling to room temperature. The amount of polymer powder was 1654 g and the MFR (230 ⁰ C, 2.16 kg) of the powder was 10 g/10 min, C2 content was 6.5 wt.-%.

After spilling the reactor with N ₂ the polymer powder is transferred to a steel container. lOOg powder, used for characterization, was stabilized with 0.1 wt.-% of Sandostab

P-EPQ and 0.2 wt.-% of Ionol CP in acetone and dried over night in a hood and additionally for 2 hours at 50 ⁰ C under vacuum.

For mechanical testing reactor product was pcllctised via TSE 16 extruder (PRISM) and additivalcd with 0.15 wt.-% Irganox B225 and 0.05 wt.-% Ca-stearatc. All samples have been nucleated with 0.2% l ,3:2,4-bis(3,4- dimcιhylbcnzylidcnc)sorbitol.

Example 2: DCPDMS; MFR 9 g/10 min ; C2 content 6.5 wl.-% (Inventive) The propylene polymers used for the present invention were prepared according to the following procedure: Raw Materials: - Hexane dried over molecular sieve (3/1 OA)

TEAL: 93 % from Sigma-Aldrich

Donor: Di-iso-propyldiethoxisilane ex Wacker Chemic (Manufacture of the donor is described in DE 38 21 483 Al) N ₂ : supplier AGA, quality 5.0; purification with catalyst BASF R031 1, catalyst Gl 32 (CuO/ZNO/C), molecular sieves (3/10A) and P ₂ O ₅ .

Hydrogen: supplier AGA, quality 6.0

Propylene: supplier Borealis

Ethylene: supplier Air Liquidc 3.5

The catalyst Poly track 8502 is commercially available from Grace. - Sandoslab P-EPQ is an antioxidant and commercially available from Clariant

Millad 3988 is a nucleating agent and commercially available from Millikcn ϊrganox B215 is a blend of antioxidants, commercially available from Ciba

Calziumstcarat S is an acid scavenger and commercially available from Faci.

Ionol CP is an antioxidant and commercially available from Dcgussa. The monomers used were additionally purified via BASF catalyst R3-1 1 (Cu), GlRDLER catalyst (CuO/ZnO) and molecular sieves 4 and 10 A. Preparation:

A 20 1 autoclave reactor has been purified by mechanical cleaning, washing with hcxanc and heating under vacuum/Nϊ cycles at 160 ⁰ C. After testing for leaks with 30 bar N ₂ over night the reactor has been vacuumed and filled with 5350 g propylene by weighing and 88 nl H ₂ by pressure monitoring from a 50 1 steel cylinder. 35 mg of Polylrack 8502-catalyst are activated for 10 minutes with a mixture of Tricthylaluminium (TEAl; solution in hexane 1 mo 1/1) and

Dicyclopcntyldimethoxysilane as donor (0.3 mo 1/1 in hexane) - in a molar ratio of 10 after a contact time of 5 min - and 10 ml hexane in a catalyst feeder. The molar ratio of TEA! and Ti of catalyst is 250. After activation the catalyst is spilled with 250 g propylene into the stirred reactor with a temperature of 23 ⁰ C. Stirring speed is hold at 250 rpm. After 6 min prcpolymcrisation at 23 ⁰ C temperature is increased to 70 ⁰ C in about 16 min. After holding that temperature for 1 hour and feeding constantly 3668mln/min ethylene into the reactor polymerisation is stopped by flashing propylene and cooling to room temperature.

The amount of polymer powder was 2884 g and the MFR (230 ⁰ C, 2.16 kg) of the powder was 9 g/10 min, C2 content was 6.5 wt.-%.

After spilling the reactor with N ₂ the polymer powder is transferred to a steel container.

10Og powder, used for characterization, was stabilized with 0.1 wt.-% of Sandoslab P-EPQ and 0.2 wt.-% of lonol CP in acetone and dried over night in a hood and additionally for 2 hours at 50 ⁰ C under vacuum.

For mechanical testing reactor product was pelϊetised via TSEl 6 extruder (PRISM) and addiiivated with 0.15 wl.-% ϊrganox B225 and 0.05 wt.-% Ca-stearatc. All samples have been nucleated with 0.2% I ,3:2,4-bis(3,4- dirnethylbcnzylidene)sorbitol.

Example 3: DlPDES; MFR 1 1 g/10 min ; C2 content 4.5 wt.-% (Inventive) The propylene polymers used for the present invention were prepared according to the following procedure: Raw Materials:

Hcxanc dried over molecular sieve (3/3 OA) TEAL: 93 % from Sigma-Aldrich » Donor: Di-iso-propyldiclhoxisilanc ex Wackcr Chcmic (Manufacture of the donor is described in DE 38 21 483 Al)

N ₂ : supplier AGA, quality 5.0; purification with catalyst BASF R031 1 , catalyst G 132 (CuO/ZNO/C), molecular sieves (3/1 OA) and P ₂ O ₅ . Hydrogen: supplier AGA, quality 6.0 - Propylene: supplier Borcalis

Ethylene: supplier Air Liquide 3.5

The catalyst Po Iy track 8502 is commercially available from Grace, Sandostab P-EPQ is an antioxidant and commercially available from Clariant Millad 3988 is a nucleating agent and commercially available from Milliken - Irganox B215 is a blend of antioxidants, commercially available from Ciba

Calziumstearat S is an acid scavenger and commercially available from Faci. lonol CP is an antioxidant and commercially available from Degussa. The monomers used were additionally purified via BASF catalyst R3-11 (Cu), GIRDLER catalyst (CuO/ZnO) and molecular sieves 4 and 10 A. Preparation:

A 20 1 autoclave reactor has been purified by mechanical cleaning, washing with hcxane and heating under vacuum/N ₂ cycles at 160 ⁰ C. After testing for leaks with 30 bar N ₂ over night the reactor has been vacuumed and filled with 5350 g propylene by weighing and 16 nl H ₂ by pressure monitoring from a 50 1 steel cylinder. 35 mg of Polytrack 8502-catalyst are activated for 10 minutes with a mixture of Tricthylaiuminium (TEAl; solution in hcxane I mol/l) and Di-iso- propyldiethoxysilane as donor (0.3 mol/l in hexanc) - in a molar ratio of 10 after a contact time of 5 min - and 10 ml hcxane in a catalyst feeder, The molar ratio of TEAl and Ti of catalyst is 250. After activation the catalyst is spilled with 250 g propylene into the stirred reactor with a temperature of 23 ⁰ C, Stirring speed is hold at 250 rpm. After 6 min prcpolymerisation at 23 ⁰ C temperature is increased to 70 ⁰ C in about 16 min. After holding that temperature for 1 hour and feeding constantly 880mln/min ethylene into the reactor polymerisation is stopped by Hashing propylene and cooling to room temperature. The amount of polymer powder was 1474 g and the MFR (230 ⁰ C, 2.16 kg) of the powder was 1 1 g/I0 min, C2 content was 4.5 wt.-%.

After spilling the reactor with N ₂ the polymer powder is transferred to a steel container. lOOg powder, used for characterization, was stabilized with 0.1 wt.-% of Sandostab P-EPQ and 0.2 wt.-% of lonol CP in acetone and dried over night in a hood and additionally for 2 hours at 50 ⁰ C under vacuum.

For mechanical testing reactor product was pcllctiscd via TSE 16 extruder (PRISM) and additivated with 0.15 wt.-% Irganox B225 and 0.05 wl.-% Ca-stcaratc. All samples have been nucleated with 0.2% l ,3:2,4-bis(3,4~ dimcthylbcnzylidene)sorbitol.

Example 4: DCPDMS; MFR 1 1 g/10 min ; C2 content 4,5 wt,-% (Comparison) The propylene polymers used for the present invention were prepared according to the following procedure; Raw Materials:

Hcxane dried over molecular sieve (3/1 OA)

TEAL: 93 % from Sigma-Aldrich

Donor: Dicyclopeniyldimcthoxysilane DCPDMS ex Wackcr Chcmic

(commercially available) - N ₂ : supplier AGA, quality 5.0; purification with catalyst BASF R031 1, catalyst G 132 (CuO/ZNO/C), molecular sieves (3/1 OA) and P ₂ O ₅ .

Hydrogen: supplier AGA, quality 6.0

Propylene: supplier Borcalis

Ethylene: supplier Air Liquide 3.5 - The catalyst Poly track 8502 is commercially available from Grace.

Sandostab P-EPQ is an antioxidant and commercially available from Clariant

Millad 3988 is a nucleating agent and commercially available from Millikcn

Irganox B215 is a blend of antioxidants, commercially available from Ciba

Calziumstcarat S is an acid scavenger and commercially available from Faci. - lonol CP is an antioxidant and commercially available from Degussa.

The monomers used were additionally purified via BASF catalyst R3-1 1 (Cu), GIRDLER catalyst (CuO/ZnO) and molecular sieves 4 and 10 A. Preparation:

A 20 1 autoclave reactor has been purified by mechanical cleaning, washing with hexane and heating under vacuum/N ₂ cycles at 160 ⁰ C. After testing for leaks with 30 bar N ₂ over night the reactor has been vacuumed and filled with 5350 g propylene by weighing and 80 nl H ₂ by pressure monitoring from a 50 1 steel cylinder. 35 mg of Poiylrack 8502-catalyst are activated for 10 minutes with a mixture of Trietbylaluminiurn (TEAl; solution in hexane 1 mol/1) and Dicyclopentyldimcthoxysilane as donor (0.3 mol/1 in hexane) - in a molar ratio of 10 after a contact time of 5 min - and 10 ml hexane in a catalyst feeder. The molar ratio of TEAl and Ti of catalyst is 250. After activation the catalyst is spilled with 250 g propylene into the stirred reactor with a temperature of 23 ⁰ C. Stirring speed is hold at 250 rpm. After 6 min prcpolymerisation at 23 ⁰ C temperature is increased to 70 ⁰ C in about 16 min. After holding that temperature for 1 hour and feeding constantly

1612mln/min ethylene into the reactor polymerisation is stopped by flashing propylene and cooling to room temperature.

The amount of polymer powder was 2313 g and the MFR (230 °C, 2.16 kg) of the powder was 1 1 g/10 min, C2 content was 4.5 wt.-%. After spilling the reactor with N ₂ the polymer powder is transferred to a steel container. lOOg powder, used for characterization, was stabilized with 0.1 wt.-% of Sandostab P-EPQ and 0.2 wt.-% of Ionol CP in acetone and dried over night in a hood and additionally for 2 hours at 50 ⁰ C under vacuum. For mechanical testing reactor product was pellctised via TSE 16 extruder (PRISM) and additivatcd with 0.15 wt.-% Irganox B225 and 0,05 wl.-% Ca-stearatc. All samples have been nucleated with 0,2% l,3:2,4-bis(3,4- dimcthylbcnzylidcne)sorbitol. All other examples given in the tables (inventive and comparison examples) can be analogous obtained by changing the hydrogen content and the ethylene feed as well as the external donor in known manner. The donors used have the following abrcvations: DlPDES Di-iso-proρydielboxysilane

DIPDMS Di-isopropydimcthoxysilane

DCPDES Dicyclopcntyldictboxysilanc

DCPDMS Dicyclopcnlyldimethoxysilanc

ClIMDES Cyclohexyldiethoxysilanc

ClIMDMS Cyclohexyldimelhoxysilanc

IPTES Iso-piOpyhriethoxysilane

Table 1: Inlπnsic viscosity

IV MFR IV (XS) dl/g g/10min dl/g

DCPDMS 26 18 06

22 49 05

19 79 04

18 95 04

18 107 043

18 126 03

17 135 04

17 135 03

I 8 138 04

17 159 03

16 204 03

I 4 343 02

I 4 381 02

DIPDbS 43 02 27

23 33 I 4

21 49 I 0

19 108 12

I 8 124 1 1

18 126 07

18 138 08

16 161 10

17 169 07

16 174 09

16 185 06

16 195 08

16 236 06

13 410 06

I 3 542 04

Table 2: Values ' with regard to the Figures 3 1 Io 1 ; '. 19 anc 1 20

C2 Flex Impact

Donor XS total Tm Tc IV (XS) Haze content modulus at 23°C

[wt.-%] |wt,-%] [ ⁰ C] I ⁰ C] [cll/g] [%] [Mpaj [kJ/m ² ]

DCPDMS 5.5 3.5 0.3 26.7 1143 5.6

DCPDMS 6.3 4.5 0.4 24.3 1022.7 5.8

DCPDMS 7.1 5 152 103 0.4 23.7 952.5 6.3

DCPDMS 8.6 6 S47 96 0.6 21.9 748.5 8.5

DCPDMS 15.0 6.5 144 92 1 .1 21.8 520.4 19.7

DIPDES 9.6 3.5 0.7 31.2 935, 1 7.7

DIPDES 12.3 4.5 08 26.1 817 8.6

DIPDES 12.4 5 152 103 0.7 23.5 775.5 8.2

DIPDES 15.7 6 149 100 1.1 27.4 573.8 25.4

DIPDES 20. 6.5 149 99 1.2 28 515 30.8

Table 3: Values with regard to Figure 18

Charpy Impact Strength [kJ/m ³ ] Charpy Impact Strength [kj/m ²

Temperature [ ⁰ C] DCPDMS DIPDES

0 8.9 9.9

2 9.7 10.6

4 9,4 1 1.8

6 9,0 15.5

8 10.7 24.4

10 1 1 ,7 24.7

12 13.6 26.6

14 16.3 27.6

16 17.0 27,3

18 17.2 27.8

20 17.6 27.4

Table 4: SIST values

C2

Doπoi lnil δHM1 LcI Tm2 δHM2 Lc2 TM3 AIIM3 Lc3 content

|wt%] [ ⁰ C] [J/g] [ran] [ ⁰ CI fJ/g] Inm) I ⁰ C] [J/g] [nm|

35 DCPDMS 1535 315 U l 141 S 451 79 1270 80 59

5 DCPDMS 1520 290 106 1390 380 75 1260 92 58

6 DCPDMS 1456 167 88 1377 223 73 1280 180 60 65 DCPDMS 1424 127 81 1285 261 61 1150 83 49 35 DIPDFS 1547 372 115 1473 160 92 1399 163 77

5 DlPDhS 1500 320 99 1390 290 75 1240 91 56

6 DIPDhS 1498 233 99 1381 213 74 1248 85 57 65 DIPDFS 1493 219 97 1372 198 72 1246 97 57

C2

Donor Tm4 λHM4 Lc4 FmS λHM5 Lc5 content

|wt%] [ ⁰ C] [J/g] jnm] [ ⁰ Cj |J/g] |nm]

35 DCPDMS 1180 51 51 966 99 39

5 DCPDMS 1150 49 49 1010 63 41

6 DCPDMS 1157 65 50 993 106 40 65 DCPDMS 975 196 39 35 DlPDFS 1150 32 49 911 43 36

5 DIPDES 1ϊ40 53 48 996 109 40

6 DIPDES 1142 48 48 978 84 39 65 DIPDES 1141 65 48 960 152 38

Table 5: Values for figure 21

Donoi XS total IK C2 tot MlR lw(%] !mol%] Ig/JOmπi 2.1kg]

( HMDPS 173 79 24

CHMDbS 207 84 293

IPTbS 105 61 07

IPTbS 203 85 876

DCPDbS 260 104 02

DCPDbS 84 4 74

DlPDbS 134 64 07

DIPDbS 270 96 915

CHMDbS 104 49 391

CHMDbS 373 161 10

IS ³ TbS 89 51 129

11' IbS 363 146 03

DCPDbS 156 9 45

DCPDbS 125 65 07

DlPDL S IO S 40 137

DIPDhS 334 136 03

CHMDMS 121 108 02

CHMDMS 48 3ή 417

DCPDMS 100 78 0 ϊ

DCPDMS 35 32 16

DlPDMS 63 46 02

DIPDMS 91 73 31

DIPDMS 63 55 8

CHMDMS m 82 27

CHMDMS 65 48 04

DCPDMS 90 82 9

DCPDMS 52 44 01

DIPDMS 57 43 41

DIPDMS 130 98 01

CI IMDMS 84 64 12

Table 6: Values for figures 22 and 23

MFR

Donor IV xs C2 content

[g/10min 2,1kg] fml/gl [mol%]

CHMDES 2935 598 84

IPTES 08 2359 61

IPTES 876 81 I 85

DCPDPS 02 3676 104

DCPDbS 740 400 40

DIPDES 07 2402 64

DIPDES 915 892 96

CIIMDFS 3908 577 49

CIIMDES 10 3109 161

IPTFS 1290 448 51

ϊPThS 03 3115 146

DCPDES 451 744 90

DCPDLS 07 2321 65

DIPDES 1368 468 46

DIPDES 03 3623 136

CIIMDMS 02 3493 108

ClIMDMS 418 342 36

DCPDMS 0 i 3558 78

DCPDMS 160 337 32

DIPDMS 02 2160 46

DϊPDMS 309 774 73

DIPDMS 79 588 55

CHMDMS 266 1446 82

COMDMS 04 2087 48

DCPDMS 96 723 82

DCPDMS 01 2191 44

DIPDMS A\ 2 355 43

DIPDMS 01 3894 98

CIIMDMS 113 674 66

Table 7: Values for figure 24

Donor IV IV (XS) MFR C2 content

|ml/g| Iml/g] [g/lOinui 2.1kg] [mol%]

CiIMDLS 2756 2200 24 79

CHMDLS 883 598 293 84

IPTbS 3594 2359 075 61

11* IbS 1142 81 I 876 85

DCPDI-S 4309 3676 023 104

DCPDbS 1212 400 74 4

D)PDbS 3663 2402 069 64

DlPDbS 1195 892 915 96

CHMDbS 839 S77 391 49

CHMDLS 3080 3109 097 161

IPIbS 1071 448 129 51

IPHS 4401 3115 027 146

DCPDhS 1306 744 45 9

DCPDbS 3557 232 I 068 65

DIPDγS 1054 468 137 46

DIPDI S 4115 3623 03 136

CHMDMS 4227 3493 024 108

CHMDMS 1376 342 417 36

DCPDMS 5685 3558 008 78

DCPDMS 1713 337 16 32

DIPDMS 4831 2160 017 46

DIPDMS 1451 774 31 73

DIPDMS 1936 588 8 55

CHMDMS 1550 1446 27 82

CHMDMS 3900 2087 04 48

DCPDMS 1910 723 9 82

DCPDMS 4882 2191 014 44

DiPDMS 1396 355 41 43

DiPDMS 5377 3894 01 98

CIIMDMS 1805 724 12 64

Table 8: Values for figuic 25

C2tot C2 random C2 block MFR

[mol%] [mol%] [moϊ%] [g/10min 2.1kg]

171 79 92 097

121 64 57 293

134 64 7 023

104 55 49 451

152 76 76 03

128 68 6 915

162 81 81 03

109 61 48 876

106 51 55 024

94 49 45 266

106 51 55 008

89 47 42 95

117 57 6 01

9 46 44 31

Table 9: Values for figures 5 and 6

Donor MIR C2 peak! aceal peλk2 arca2 pcak3 aιea3 jg/lOmin 2.1kg] |wt%] I ⁰ C] |wl%] ( ⁰ C] !«t%i J ⁰ C] [vK%.

DCPDMS 10 5 1042 937 00 00 00 00

DCPDMS 10 6 992 933 00 00 00 00

DCPDMS 10 65 960 868 00 00 00 00

DiPDbS 10 5 1041 782 723 24 675 95

DlPDbS 10 6 1030 675 755 164 00 00

D)PDLS 10 65 1008 560 799 06 789 223