GARAGNANI ENEA (IT)
PELLEGATTI GIAMPAOLO (IT)
ANGELINI ANTONELLA (IT)
PELLICONI ANTEO (IT)
GARAGNANI ENEA (IT)
PELLEGATTI GIAMPAOLO (IT)
ANGELINI ANTONELLA (IT)
WO2000026295A1 | 2000-05-11 | |||
WO2002028958A2 | 2002-04-11 | |||
WO2003076508A1 | 2003-09-18 |
R11 ^ CH2ORIV wherein R1 and Rπ are the same or different and are C1-C18 alkyl, C3-C18 cycloalkyl or C7- C18 aryl radicals; R111 and RIV are the same or different and are C1-C4 alkyl radicals; or are the 1,3-diethers in which the carbon atom in position 2 belongs to a cyclic or polycyclic structure made up of 5, 6 or 7 carbon atoms and containing two or three unsaturations. Ethers of this type are described in published European patent applications 361493 and 728769. Representative examples of said dieters are 2-methyl-2-isopropyl-l,3-dimethoxypropane, 2,2-diisobutyl- 1 ,3 -dimethoxypropane, 2-isopropyl-2-cyclopentyl- 1 ,3 -dimethoxypropane, 2- isopropyl-2-isoamyl-l,3-dimethoxypropane, 9,9-bis (methoxymethyl) fluorene. The preparation of the above mentioned catalyst components is carried out according to various methods. For example, a MgCl2 -nROH adduct (in particular in the form of spheroidal particles) wherein n is generally from 1 to 3 and ROH is ethanol, butanol or isobutanol, is reacted with an excess of TiCl4 containing the electron-donor compound. The reaction temperature is generally from 80 to 120° C. The solid is then isolated and reacted once more with TiCl4, in the presence or absence of the electron-donor compound, after which it is separated and washed with aliquots of a hydrocarbon until all chlorine ions have disappeared. In the solid catalyst component the titanium compound, expressed as Ti, is generally present in an amount from 0.5 to 10% by weight. The quantity of electron-donor compound which remains fixed on the solid catalyst component generally is 5 to 20% by moles with respect to the magnesium dihalide. The titanium compounds which can be used for the preparation of the solid catalyst component are the halides and the halogen alcoholates of titanium. Titanium tetrachloride is the preferred compound. The reactions described above result in the formation of a magnesium halide in active form. Other reactions are known in the literature, which cause the formation of magnesium halide in active form starting from magnesium compounds other than halides, such as magnesium carboxylates. The Al-alkyl compounds used as co-catalysts comprise the Al-trialkyls, such as Al- triethyl, Al-triisobutyl, Al-tri-n-butyl, and linear or cyclic Al-alkyl compounds containing two or more Al atoms bonded to each other by way of O or N atoms, or SO4 or SO3 groups. The Al-alkyl compound is generally used in such a quantity that the Al/Ti ratio be from 1 to 1000. The electron-donor compounds that can be used as external donors include aromatic acid esters such as alkyl benzoates, and in particular silicon compounds containing at least one Si-OR bond, where R is a hydrocarbon radical. Examples of silicon compounds are (tert-butyl)2Si(OCH3)2, (cyclohexyl)(methyl)Si (OCH3)2, (phenyl)2Si(OCH3)2 and (cyclopentyl)2Si(OCH3)2. 1,3-diethers having the formulae described above can also be used advantageously. If the internal donor is one of these dieters, the external donors can be omitted. Other catalysts that may be used in the process according to the present invention are metallocene-type catalysts, as described in USP 5,324,800 and EP-A-O 129 368; particularly advantageous are bridged bis-indenyl metallocenes, for instance as described in USP 5,145,819 and EP-A-O 485 823. Another class of suitable catalysts are the so-called constrained geometry catalysts, as described in EP-A-O 416 815 (Dow), EP-A-O 420 436 (Exxon), EP-A-O 671 404, EP-A-O 643 066 and WO 91/04257. These metallocene compounds may be used in particular to produce the component (B). The catalysts can be pre-contacted with small amounts of olefins (prepolymerization). The masterbatch composition of the present invention can also contain additives commonly employed in the art, such as antioxidants, light stabilizers, heat stabilizers, colorants and fillers. As previously said, the masterbatch composition of the present invention can be advantageously compounded with additional polyolefms, in particular propylene polymers such as propylene homopolymers, random copolymers, and thermoplastic elastomeric polyolefin compositions. Accordingly, a second embodiment of the invention relates to a thermoplastic polyolefin composition suitable for injection molding, containing the above- defined masterbatch compositions. Preferably, the said thermoplastic polyolefin composition comprises up to 60% by weight, typically from 20% to 60% by weight, more preferably from 25% to 55% by weight of the masterbatch composition according to the present invention. Practical examples of the polyolefins to which the masterbatch is added (i.e. the polyolefms other than those present in the masterbatch) are the following polymers: 1) crystalline propylene homopolymers, in particular isotactic or mainly isotactic homopolymers; 2) crystalline propylene copolymers with ethylene and/or a C4-CiO α-olefin, wherein the total comonomer content ranges from 0.05 to 20% by weight with respect to the weight of the copolymer, and wherein preferred α-olefins are 1-butene; 1-hexene; 4-methyl-l- pentene and 1 -octene; 3) crystalline ethylene homopolymers and copolymers with propylene and/or a C4-CiO α- olefin, such as HDPE; 4) elastomeric copolymers of ethylene with propylene and/or a C4-CiO α-olefins, optionally containing minor quantities of a diene, such as butadiene, 1 ,4-hexadiene, 1,5-hexadiene and ethylidene-1-norbornene, wherein the diene content is typically from 1 to 10% by weight; 5) a thermoplastic elastomeric composition comprising one or more of propylene homopolymers and/or the copolymers of item 2) and an elastomeric moiety comprising one or more of the copolymers of item 4), typically prepared according to known methods by mixing the components in the molten state or by sequential polymerization, and generally containing the said elastomeric moiety in quantities from 5 to 80% by weight. The polyolefin composition may be manufactured by mixing the masterbatch composition and the additional polyolefin(s) together, extruding the mixture, and pelletizing the resulting composition using known techniques and apparatus. The polyolefin composition may also contain conventional additives such as mineral fillers, colorants and stabilizers. Mineral fillers that can be included in the composition include talc, CaCO3, silica, such as wollastonite (CaSiO3), clays, diatomaceaous earth, titanium oxide and zeolites. Typically the mineral filler is in particle form having an average diameter ranging form 0.1 to 5 micrometers. The present invention also provides final articles, such as bumpers and fascia, made of the said polyolefin composition. The practice and advantages of the present invention are disclosed below in the following examples. These Examples are illustrative only, and are not intended to limit the scope of the invention in any manner whatsoever. The following analytical methods are used to characterize the polymer compositions. Melt Flow Rate: ASTM-D 1238, condition L. pηl intrinsic viscosity: determined in tetrahydronaphtalene at 135°C. Ethylene content: LR. Spectroscopy. Flexural Modulus: ISO 178, measured 24 hours after moulding. Tensile strength at yield: ISO 527, measured 24 hours after moulding. Tensile strength at break: ISO 527, measured 24 hours after moulding. Elongation at break and at yield: ISO 527, measured 24 hours after moulding. Notched IZOD impact test: ISO 180/1 A The IZOD values are measured at 23 °C and -30 °C, 3 hours and 24 hours after moulding, and at -50 °C, 24 hours after moulding. Xylene soluble and isoluble fractions 2.5 g of polymer and 250 cm3 of xylene are introduced in a glass flask equipped with a refrigerator and a magnetical stirrer. The temperature is raised in 30 minutes up to the boiling point of the solvent. The so obtained clear solution is then kept under reflux and stirring for further 30 minutes. The closed flask is then kept for 30 minutes in a bath of ice and water and in thermostatic water bath at 25 °C for 30 minutes as well. The so formed solid is filtered on quick filtering paper. 100 cm of the filtered liquid is poured in a previously weighed aluminum container which is heated on a heating plate under nitrogen flow, to remove the solvent by evaporation. The container is then kept in an oven at 80 0C under vacuum until constant weight is obtained. The weight percentage of polymer soluble in xylene at room temperature is then calculated. The percent by weight of polymer insoluble in xylene at room temperature is considered the isotacticity index of the polymer. This value corresponds substantially to the isotacticity index determined by extraction with boiling n-heptane, which by definition constitutes the isotacticity index of polypropylene. Longitudinal and transversal thermal shrinkage A plaque of 100 x 200 x 2.5 mm is moulded in an injection moulding machine "SANDRETTO serie 7 190" (where 190 stands for 190 tons of clamping force). The injection conditions are: melt temperature = 250°C; mould temperature = 400C; injection time = 8 seconds; holding time = 22 seconds; screw diameter = 55 mm. The plaque is measured 3 hours and 24 hours after moulding, through callipers, and the shrinkage is given by: τ ., ,. . , . . 200 - read value 1 ΛA Longitudmal shrinkage = = x 100 200 „ i i_ • i 100 - read value 1 n _ Transversal shrinkage = = x 100 IOO wherein 200 is the length (in mm) of the plaque along the flow direction, measured immediately after moulding; IOO is the length (in mm) of the plaque crosswise the flow direction, measured immediately after moulding; the readjyalue is the plaque length in the relevant direction. Examples 1-7 Preparation of the masterbatch composition The solid catalyst component used in polymerization is a highly stereospecific Ziegler- Natta catalyst component supported on magnesium chloride, containing about 2.5% by weight of titanium and diisobutylphthalate as internal donor, prepared by analogy with the method described in the examples of European published patent application 674991. CATALYST SYSTEM AND PREPOLYMERIZATION TREATMENT Before introducing it into the polymerization reactors, the solid catalyst component described above is contacted at -5 °C for 5 minutes with aluminum triethyl (TEAL) and dicyclopentyldimethoxysilane (DCPMS), in a TEAL/DCPMS weight ratio equal to about 15 and in such quantity that the TEAL/Ti molar ratio be equal to 65. The catalyst system is then subjected to prepolymerization by maintaining it in suspension in liquid propylene at 20 0C for about 20 minutes before introducing it into the first polymerization reactor. POLYMERIZATION Into a first gas phase polymerization reactor a polypropylene homopolymer (component (A)) is produced by feeding in a continuous and constant flow the prepolymerized catalyst system, hydrogen (used as molecular weight regulator) and propylene in the gas state. Polymerization conditions are shown in Table I. The polypropylene homopolymer coming from the first reactor is discharged in a continuous flow and, after having been purged of unreacted monomers, is introduced, in a continuous flow, into a second gas phase reactor, together with quantitatively constant flows of hydrogen and ethylene in the gas state. In the second reactor a propylene/ethylene copolymer (component (B)) is produced. Polymerization conditions, molar ratio of the reactants and composition of the copolymers obtained are shown in Table I. The polymer particles exiting the second reactor, which constitute the not stabilized masterbatch according to the present invention, are subjected to a steam treatment to remove the reactive monomers and volatile substances, and then dried. Then the polymer particles are introduced in a rotating drum, where they are mixed with 0.05% by weight of paraffin oil ROL/OB 30 (having a density of 0.842 kg/1 at 20 °C according to ASTM D 1298 and flowing point of -10 0C according to ASTM D 97), 0.15% by weight of Irganox® B 215 (made of about 34% Irganox® 1010 and 66% Irgafos® 168) and 0.04% by weight of DHT-4A (hydrotalcite). The said Irganox 1010 is 2,2-bis[3-[,5-bis(l,l-dimethylethyl)-4-hydroxyphenyl)-l- oxopropoxy]methyl] - 1 ,3 -propanediyl-3 ,5-bis( 1 , 1 -dimethylethyl)-4-hydroxybenzene- propanoate, while Irgafos 168 is tris(2,4-di-tert.-butylphenyl)phosphite. Then, the polymer particles are extruded under nitrogen in a screw extruder with a melt temperature of 200-250 °C. The characteristics relating to this polymer composition, reported in Table II, are obtained from measurements carried out on the so extruded polymer, which constitute the stabilized masterbatch composition according to the present invention. Table I
EXAMPLE 1 2 3 4 5 6 7 1° REACTOR (component (A)) Temperature (° C) 75 75 75 75 75 75 75 Amount produced (wt%) 31 31 33 30 30 30 25 MFRA (g/10 min.) 146 86 87 78 107 81 19.8 Xylene soluble (wt%) 3.6 3.6 3.5 3.5 3.5 3.5 3.3 2° REACTOR (component (B)) Temperature (° C) 65 65 65 65 65 65 65 Amount produced (wt%) 69 69 67 70 70 70 75 C2/(C2+C3) mol 0.58 0.58 0.58 0.645 0.635 0.63 0.6 C2 in (B) (wt%) 69.5 67 69 75.5 73.5 72 66.5 Xylene soluble in (B) (wt%) 65.5 68 66 57 59 61.5 69.5 Notes: C2 = ethylene; C3 = propylene Table II
EXAMPLE 1 2 3 4 5 6 7 MFR (g/10 min) 4.2 4.2 4.9 4.2 5.2 5.6 2 Xylene soluble (wt%) 46.4 48.2 45.6 41.1 42.5 44 53.1 Ethylene content (wt%) 48 46.2 46.3 52.9 51.4 50.3 50 [η]∞i (dl/g) 1.93 1.85 1.79 1.8 1.72 1.58 1.95 Flexural modulus (MPa) 340 338 309 400 350 370 255 Tensile strength at yield (MPa) 8 8.3 8.2 9.4 8.7 8.7 7.1 Elongation at yield (%a) 31.3 31.8 10.9 32.3 27.8 28.7 46 Tensile strength at break (MPa) >12 13 >10 > 14.9 > 13.7 13.2 >13 Elongation at break (%) >597 597 >640 >595 >600 570 >600 IZOD Impact Str. at -50° C (KJ/m2) 86.9 41.5 88.9 25.9 23.1 46.1 N.B. MFR / [η]soI 2.2 2.3 2.7 2.3 3 3.5 1 Note: N.B. = No Break Preparation of blends of the stabilized masterbatch composition with propylene polymers The stabilized masterbatch compositions prepared as described above (hereinafter called SMC) are blended by extrusion under the previously described conditions with a heterophasic polypropylene composition (hereinafter called HPP) and the other additives hereinafter described, in the proportions reported below and in Table III.. The properties of the so obtained final compositions are reported in Table III. Added components 1 HPP: heterophasic polypropylene composition having MFR of 60 g/10 min., made of 80% by weight of propylene homopolymer with isotactic index of 98%, and 20% by weight of an ethylene/propylene copolymer containing 60% by weight of ethylene; 2 CB: carbon black masterbatch having MFR of about 40 g/10 min., made of 40% by weight of carbon black and 20% of a copolymer of propylene with 7% by weight of ethylene; 3 ROL/OB 30: see above; 4 Irganox® B 225: made of about 50% Irganox® 1010 and 50% Irgafos® 168; 5 HM05 talc: fine talc powder with average particle size of about 2 μm. In all the examples, the added amounts of components 2 to 5 are the following (percent by weight): Component Amount 2 1.76% 3 0.05% 4 0.2% 5 20% Table III
SMC of EXAMPLE 1 2 3 4 5 6 7 SMC amount (wt%) 43 43 45 43 43 43 33 HPP amount (wt%) 34.99 34.99 32.99 34.99 34.99 34.99 44.99 Flexural modulus (MPa) 1217 1214 1203 1250 1216 1226 1490 Tensile strength at yield (MPa) - - - - - - 16.8 Elongation at yield (%a) - - - - - - 5.9 Tensile strength at break (MPa) - - - - - - 13 Elongation at break (%) - - - - - - 60 IZOD Impact Str. at -30° C (KJ/m2) 5.7 4.7 4.8 3.9 4.1 3.9 4.2 Longitudinal shrinkage (%) 0.33 0.34 0.34 0.37 0.36 0.35 0.45 Transversal shrinkage (%) 0.48 0.49 0.49 0.53 0.51 0.49 0.63 MFR (g/10 min) 18 17.8 18.3 20.7 21.7 17.9