For the purpose of this patent, polyketones are defined as linear polymers having an alternating structure of (a) units derived from carbon monoxide and (b) units derived from one or more olefinically unsaturated compounds. Such polyketones have the formula: where the R', R2, R3 and R4 groups are independently hydrogen or hydrocarbyl groups, and m is a large integer; they are disclosed in several patents e. g. US 3694412.

Processes for preparing the polyketones are disclosed in US 3694412 and also in EP 181014 and EP 121965. Although for the purposes of this patent polyketones correspond to this idealised structure, it is envisaged that materials corresponding to this structure in the main but containing small regimes (i. e. up to 10wt%) of the corresponding homopolymer or copolymer derived from the olefinically unsaturated compound, also fall within the definition.

US 4,816,514 relates to blends of linear alternating polyketones with a polyolefin. Preferred polyolefins include polyethylene, polypropylene, poly (1-butene) and poly (4-methyl-1-pentene). The blends of US 4,816,514 comprise a major proportion of the polyketone polymer and a minor proportion of the polyolefin polymer (up to about 35 % by weight). It is stated that the polyketone/polyolefin polymer blend is a non-miscible blend with the polyolefin polymer existing as a discrete phase in the

polyketone matrix and having a phase size of from about 5 microns to about 15 microns.

The blends are not homogeneous but satisfactory blends are said to be obtained when the distribution of the polyolefin phase throughout the polyketone polymer is substantially uniform. The compatibility of polyketone/polypropylene blends containing higher amounts of polypropylene would be expected to be poor.

H917 relates to blend of a linear alternating polyketone polymer with a maleated polyolefin polymer. The minor component of the blend is the maleated polyolefin polymer (a polymeric adduct of a polyolefin polymer and a maleic acid compound).

Preferred polyolefin precursors of the maleated polyolefin polymer include polypropylene, polybutylene or copolymers of propylene or butylene with up to about 12 % mol of ethylene. It is said that quantities of maleated polyolefin in the blend of from about 0.5 to about 40 wt %, based on the total blend are satisfactory. Again, it is important that a relatively uniform mixture of the maleated polyolefin throughout the polyketone polymer is obtained.

US 5,369,170 relates to aminated polyolefins which are capable of grafting to polyketone polymers, for example, during a blending process. The formation of primary amine functionalised polyolefins is achieved by the melt reaction of an amine with a maleated polyolefin. A particularly preferred maleated polyolefin is maleic anhydride modified polypropylene. Example 2 of US 5,369,170 demonstrates diluting an amine modified polypropylene in blends of polypropylene homopolymer. However, a blend of an aminated polyolefin, polypropylene and a polyketone is not exemplified.

Polypropylene is currently used in a wide variety of engineering type applications, for example, in the automobile and household appliance industries. Thus, (a) automobile parts and (b) fascias, panels, doors, and interiors of household appliances, such as refrigerators, freezers and vacuum cleaners, may be formed from polypropylene. Garden furniture and toys are also often formed from polypropylene while polypropylene may also be extruded into pipes and tubes. However, polypropylene is susceptible to abrasion during use (i. e. scratches readily) which detracts from the appearance of the product. It has now been found that by blending a minor proportion of a polyketone with a major proportion of a polypropylene in the presence of an amine-functionalised polyolefin or an amide-functionalised polyolefin that the scratch resistance of the polypropylene is markedly improved. It has also been found that the thermal properties, barrier properties

and mechanical performance (e. g. impact strength) of polypropylene/polyketone blends can be significantly improved by blending polyketone with polypropylene in the presence of an amine-functionalised polyolefin or an amide-functionalised polyolefin.

Thus according to the present invention there is provided a polymer blend comprising: (A) a linear polyketone having an alternating structure of (a) units derived from carbon monoxide and (b) units derived from one or more olefinically unsaturated compounds; (B) polypropylene; and (C) an amine-functionalised polyolefin or an amide-functionalised polyolefin, wherein the polypropylene is present in the polymer blend in an amount of above 40 wt %.

Without wishing to be bound by any theory it is believed that the amine- functionalised polyolefin or the amide-functionalised polyolefin acts as a compatibiliser allowing improved mixing and interfacial adhesion of the polyketone and polypropylene components of the polymer blend. Compatabilisation of the blend also allows a higher proportion of polypropylene to be incorporated into the polymer blend than in the absence of a compatibiliser.

Preferably, polypropylene is present in the blend of the present invention in an amount of at least 50 wt%, more preferably at least 60 wt %, most preferably at least 75 wt %, for example 85 wt %. Preferably the polypropylene is present in the blend in an amount in the range 50 to 90 wt %, more preferably 60 to 90 wt %, most preferably 70 to 90 wt %.

Polypropylene is a term well known in the art. Polypropylene polymers are normally solid, high molecular weight, highly crystalline, homopolymers of propylene or a copolymer of propylene with a small amount e. g. 0.1 to 5 weight% of an alpha-olefin comonomer (e. g. ethylene or a C4-Cg alpha olefin) for property modification. The density of polypropylene is typically in the range 0.900 to 0.905 g/cm3, for example, about 905g/cm3. The melt index (2.16kg load at 230°C, using a 2.095 mm diameter die) of the polypropylene is suitably in the range 0.1 to 50, preferably 1 to 20 for example, 3 g/10 minutes.

The polymer blend may comprise more than one polypropylene.

The term polypropylene, as used herein, includes polymers having a polypropylene backbone grafted with 0.001 to 30% by weight of at least one polymerisable ethylenically unsaturated carboxylic acid or derivative thereof. Blends of two or more polypropylenes can be used in the grafting process.

Polymerisable ethylenically unsaturated carboxylic acids and derivatives thereof include, for example, acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, maleic anhydride, 4-methyl cyclohex-4-ene-1,2-dicarboxylic acid anhydride, bicyclo (2.2.2) oct-5-ene-2,3-dicarboxylic acid anhydride, 1,2,3,4,5,8,9,10- octahydronaphthalene-2,3 dicarboxylic acid anhydride, 2-oxa-1,3-diketospiro (4.4) non- 7-ene, bicyclo (2.2.1) hept-5-ene-2,3-dicarboxylic acid anhydride, maleopimaric acid, tetrahydrophthalic anhydride, x-methyl-bicyclo (2.2.1) hept-5-ene-2,3-dicarboxylic acid anhydride, x-methyl-norborn-5-ene-2, dicarboxylic acid anhydride, norborn-5-ene-2,3- dicarboxylic acid anhydride. Preferably, maleic anhydride is used. When maleic anhydride is used as the polymerisable ethylenically unsaturated carboxylic acid anhydride, the amount which is graft copolymerised with the polypropylene backbone is typically from 0.001 to 30%, preferably from 0.1 to 10% more preferably from 0.15 to 5 % by weight of the grafted copolymer.

Co-grafting monomers such as, for example, those described in US Patent 3882194 may also be used for preparing the graft copolymers of the polypropylene and polymerisable ethylenically unsaturated carboxylic acid or derivative thereof.

Methods for preparing graft copolymers are well known and any suitable method can be used to prepare the graft copolymer of the polypropylene and polymerisable ethylenically unsaturated carboxylic acid or derivative thereof. One such suitable method comprises blending together the polypropylene and the polymerisable ethylenically unsaturated carboxylic acid or derivative thereof in the presence of a free radical initiator, such as an organic peroxide or hydroperoxide, at a temperature which is above the melting point of the polyolefin and which provides a suitable half-life of the free radical initiator. Suitable free radical initiators are well known. This grafting process can be carried out using known mixing equipment such as, for example, a Brabender mixer, a Banbury mixer or a roll mill. Preferably, the grafting process is carried out in a closed vessel. A convenient method of preparing the graft copolymer is therefore to extrude the polypropylene which forms the polymer backbone, the

polymerisable ethylenically unsaturated carboxylic acid or derivative thereof and an organic peroxide or hydroperoxide through a single or multiple screw extruder.

Alternatively, the polypropylene may be dissolved or suspended in a solvent and the resulting solution or suspension is mixed with the polymerisable ethylenically unsaturated carboxylic acid or derivative thereof and the free radical initiator.

The amine-functionalised polyolefin may be selected from the group consisting of : (i) a copolymer comprising units derived from (a) a nitrogen-containing olefinic monomer and (b) an olefinic monomer selected from the group consisting of ethylene, an alpha-olefin and a non-conjugated diene; and (ii) a graft copolymer having a polyolefin backbone grafted with 0.001 to 30% by weight of at least one polymerisable ethylenically unsaturated carboxylic acid or derivative thereof and which has been reacted with a compound (D) which has at least two amino groups selected from primary or secondary amino groups with the proviso that at least one of the amino groups is a primary amino group.

Amine-functionalised polyolefins of type (i) are obtainable by: (A) copolymerising (a) a masked nitrogen-containing olefinic monomer and (b) an olefinic monomer selected from the group consisting of ethylene, an alpha-olefin and a non-conjugated diene; and (B) demasking the resulting copolymer to form the amine-functionalised copolymer.

The preparation of amine-functionalised polyolefins of type (i) is described in US 5,030,370 which is herein incorporated by reference.

Suitably, the alpha olefins are C3 to C25 alpha-olefins. The alpha-olefins may be branched or straight chained, cyclic, aromatic substituted or unsubstituted, and are preferably C3 to C16 alpha-olefins. Mixed alpha olefins can be used (e. g. mixed butenes).

The alpha-olefins, when substituted, should not be aromatic substituted on the 2- position (e. g. moieties such as CH2=CH--should not be employed) since such an aromatic group interferes with the subsequent desired polymerisation reaction.

Examples of suitable substituted alpha-olefins are disclosed in US 5,030,370 which is herein incorporated by reference. Illustrative examples of preferred alpha-olefins are propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 1-dodecene, most preferably,

propylene.

Where an alpha olefin is incorporated in the amine-functionalised polyolefin (i), the alpha olefin is generally incorporated in an amount of between 10 and 90 wt%, more preferably 20 to 70 wt% based on the total weight of the amine-functionalised polyolefin (i).

Suitable non-conjugated dienes include straight chain hydrocarbon di-olefins or cycloalkenyl-substituted alkenes, having from 6 to 15 carbon atoms, for example: A. straight chain acyclic dienes, B. branched chain acyclic dienes, C. single ring alicyclic dienes, and D. multi-ring alicyclic fused and ridged ring dienes.

Examples of such dienes are given in US 5,030,370.

Of the non-conjugated dienes typically used, the preferred dienes are dicyclopentadiene, 1,4-hexadiene, 5-methyl-2-norbornene, and 5-ethylidene-2- norbornene.

Where a non-conjugated diene is incorporated into the amine-functionalised polyolefin (i), the non-conjugated diene is generally incorporated in an amount of from 0.5 to 15 wt%, preferably from 1 to 10 wt%, for example, 5 wt% based on the total weight of the amine-functionalised polyolefin (i).

The nitrogen-containing olefinic monomer (NCM), which is masked prior to the polymerisation, is suitably an unsaturated, nitrogen-containing olefinic monomer having the general formula: R' (X) n wherein R'is selected from ethylenically unsaturated hydrocarbyl radicals, and X is selected from the group consisting of amino (-N (H) R') groups, imino groups (-CH=N- R'), and cyano (-C=N) moieties, and wherein n is an integer of at least 1, preferably 1-4, and more preferably 1-2. R'in the above groups may comprise H or a hydrocarbyl (preferably H or saturated hydrocarbyl), for example, a saturated hydrocarbyl having 1 to 15 carbon atoms, and preferably an alkyl having 1 to 5 carbon atoms or a cycloalkyl having from 3 to 7 carbon atoms. Exemplary amino groups include-NH2 and alkyl amino groups, for example,-NHCH3, NHC2H5,-NHC3H7 and-NHC4Hg.

The unsaturation in R'is such that it is easily polymerised, for example, using a

Ziegler catalyst. R'preferably contains from 2 to 25 carbon atoms, and preferably from 2 to 16 carbon atoms. In particular, Rl is selected from the group consisting of radicals derived from ethylene, alpha-olefins, and norbornenes, or from the group consisting of vinyl and allyl radicals. Representative examples of such unsaturation are provided in US 5,030,370.

The NCM is preferably soluble in the liquid hydrocarbon solvent or diluent selected for use in the subsequent polymerisation reaction (e. g. saturated hydrocarbon solvents, such as hexene).

Suitable nitrogen-containing olefinic monomers include norbornenyl-methyl amines and imines (such as 5-norbornene-2-methylamine, 5-norbornene-2,3- dimethylamine, 5-norbornene-2-ethylamine, and 5-norbornene-2- (4'-butenyl) imine) and norbornenyl-nitriles (such as 5-norbornene-2-nitrile, and 5-norbornene-2,3-dinitrile).

The NCM may also include multiple functionality, that is the R'moiety may be substituted by more than one"X"group, in which case the functional groups"X"may be the same or different.

The nitrogen-containing monomers may be prepared by conventional methods.

Agents which are effective in masking the nitrogen-containing olefinic monomers include metal alkyls and metal alkyl hydrides and are described in detail in US 5,030,370.

The term masked, nitrogen-containing olefinic monomer (MNCM) is intended to refer to the reaction products formed by the reaction of the nitrogen-containing olefinic monomer and a masking agent comprising at least one metallic organic compound. The MNCM so formed is used as the actual comonomer in the polymerisation process. Preferred masked nitrogen-containing olefinic monomers useful for the preparation of the amine-functionalised polyolefin (i) are disclosed in US 5,030,370.

The masking reaction provides a chemical deactivation of the reactivity of the nitrogen-containing olefinic monomer otherwise the unmasked nitrogen-containing functionality would tend to react almost immediately with the catalyst under the polymerisation conditions thereby leading to a loss of activity.

The masking reaction, which can be performed in a batchwise, continuous or semi-continuous manner, is preferably carried out by adding the NCM to the selected

metal alkyl masking agent, preferably in the presence of an inert solvent or diluent.

Suitable reaction conditions for the masking reaction are disclosed in US 5,030,370.

The copolymerisation of (a) the MNCM and (b) the olefinic monomer (s) may be performed in an otherwise conventional manner using suitable methods, including batchwise, semi-batch or continuous operations in the presence of catalysts known to be effective for conventional polymerisation of olefinic monomers. Suitable catalysts and polymerisation reaction conditions are described in US 5,030,370.

After polymerisation, the polymerisation is quenched in a conventional manner (see US 5,030,370).

The desired amino functional group, i. e., X, incorporated into the amine- functionalised polyolefin (i) as the masked functional group, can be regenerated by removal of the masking metal, M, through the use of conventional demasking techniques, wherein the quenched polymerisation product, containing masked-functionalised polyolefin, the polymerisation catalyst, and unreacted monomers, is contacted with an aqueous liquid, e. g. water, aqueous solutions containing mineral acids, aqueous solutions containing mineral bases or mixtures thereof. The resulting hydrolysis reactions liberate the metal masking agent and generate the amine-functionalised polyolefin (i). Details of the hydrolysis reactions and methods of recovering other amine-functionalised polyolefin are given in US 5,030,370.

Examples of amine-functionalised polyolefins (i) for use as compatabilisers in the blends of the present invention include functionalised polypropylenes (propylene homopolymers, propylene-ethylene copolymers containing less than 10 wt % ethylene, propylene-higher olefin copolymers containing up to 10 wt% of higher alpha-olefins such as hexene-1, pentene-1, and octene-1), functionalised polyethylenes (ethylene homopolymers and ethylene-propylene copolymers containing greater than 90wt% ethylene) ethylene-propylene copolymers (e. g. elastomeric EPM), ethylene-propylene- diene terpolymers (e. g. elastomeric EPDM). Preferably, the compatibiliser is an amine- functionalised polypropylene, an amine-functionalised EPM or an amine-functionalised EPDM, most preferably an amine-functionalised polypropylene.

The NCM may be present in the amine-functionalised polyolefin (i) in an amount of from 0.01 to 40 wt%, based on the total weight of the amine-functionalised polyolefin, preferably 0.1 to 20 wt%, more preferably 0.75 to 10 wt%, and most

preferably 1 to 7 wt %.

The amine-functionalised polyolefins (i) employed in this invention have a number average molecular weight in the range 10,000 to 500,000, preferably 10,000 to 200,000, more preferably 20,000 to 150,000.

Preferably, the amine-functionalised polyolefin (i) will have within its structure, on average, at least 0.5 (e. g. from 0.5 to 20), and preferably at least 1 pendent reactive amine group (i. e. primary and/or secondary amine groups) per polymer molecule.

Preferably, the amine-functionalised polyolefins (i) have a substantially homogeneous distribution of amine functionality between the polymer chains. The distribution of the amine groups is discussed in detail in US 5,030,370.

The polyolefin which is used as the backbone of the graft copolymers (ii) can be a homopolymer of an olefin e. g. ethylene or propylene, in particular, polypropylene, high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE) or very low density polyethylene (VLDPE), preferably LLDPE or polypropylene; or a copolymer of an olefin e. g. propylene with ethylene, butene or other unsaturated aliphatic hydrocarbons or a terpolymer of an olefin e. g. ethylene with propylene and a diene. Such homopolymers, copolymers and terpolymers are known and any such polymer can be used. Blends of two or more polyolefins can be used. It is preferred that the polyolefin backbone of the graft copolymer (ii) is polypropylene, polyethylene, an ethylene-propylene rubber or an ethylene/propylene/diene polymer (EPDM), most preferably, polypropylene. Where the polyolefin backbone is a copolymer or a terpolymer it is preferred that it comprises at least 80% of polymerised ethylene or at least 80% of polymerised propylene units. It is preferred that the polyolefin used in the backbone of the graft copolymer (ii) is the same as the polypropylene component (B) of the blend.

The polyolefin backbone of graft copolymer (ii) may be grafted with the polymerisable ethylenically unsaturated carboxylic acids and derivatives thereof which are listed above.

Suitable methods for preparing the graft copolymers (ii) are those described above for preparing graft copolymers of a polypropylene and a polymerisable ethylenically unsaturated carboxylic acid or derivative thereof.

The graft copolymer (ii) is reacted with a compound (D) which has at least two

amino groups selected from primary or secondary amino groups with the proviso that at least one of the amino groups is a primary amino group. It is preferred that compound (D) is a diamine having two primary amino groups and up to 16 carbon atoms inclusive and at least two carbon atoms between the primary amino groups. The diamines suitably contain aromatic moieties linking the amino groups as illustrated by phenylenediamine, 4,4'-diaminobiphenyl and di (4-aminophenyl) ether, or the diamines contain cycloaliphatic linking moieties such as in the case of di (4-aminocyclohexyl) methane or 1,4- diaminocyclooctane. The preferred diamines, however, are acyclic terminal primary diamines of the formula: H2N (CH2) nNH2 (II) wherein n is an integer from 2 to 16 inclusive. Such polymethylenediamines include trimethylenediamine, tetramethylenediamine, hexamethylenediamine, decamethylenediamine, dodecamethylenediamine and hexadecamethylenediamine. Of these diamines dodecamethylenediamine is preferred.

Compound (D) can also suitably be a polyalkylene polyamine, or a mixture thereof, having the formula:- H2N (R-NH) nH (III) wherein R is a divalent aliphatic hydrocarbon group having 2 to 4 carbon atoms and n is an integer in the range 1 to 10. More preferably the amine is a polyalkylene polyamine of the formula (III) wherein R is the group-CH2CH2-and n has a value of 2 to 6, i. e. a polyethylene polyamine. Examples of suitable polyethylene polyamines include triethylene tetramine and tetraethylene pentamine. Hydroxyalkyl amines, for example ethanolamine, diethanolamine, 2-hydroxypropylamine and N-hydroxy-ethyl ethylenediamines, and the like may also be used as compound (D).

Furthermore, compound (D) can be a compound of formula (IV), H2N (CHR'CHR2O) nCHR3CHR4NH2 (IV) wherein one of R'and R2 is hydrogen and the other is hydrogen or lower alkyl, preferably C2 to C6 alkyl, more preferably methyl, and n is an integer from 1 to 40, preferably from 1 to 10, more preferably 1 to 7, for example 2 to 7, one of R3 and R4 is hydrogen and the other is hydrogen or lower alkyl, preferably C2 to C6 alkyl, more preferably methyl.

In particular where compound (D) is of formula (IV) it is preferred to use

compounds of formula, NH2CH (CH3) CH2 OCH2CH (CH3) NH2 where x is in the range 1 to 40, for example 33.1., 5,6 and 2.6. These compounds are commercially available and are marketed under the trade names Jeffamine D2000, D400 and D230 respectively.

Compound (D) can be reacted with the graft copolymer in several ways; a preferred method however is to react them in a melt by melt mixing them in known mixing equipment e. g. a Brabender mixer, a Banbury mixer or a roll mill or twin screw extruder. It is possible to melt mix the diamine with the graft copolymer in the grafting process itself, preferably in 2 steps. The reaction of compound (D) with the graft copolymer can be carried out either before or at the same time as mixing with the polypropylene (B). However, it is preferred that the graft copolymer is first reacted with compound (D) and then mixed with (B).

The amide-functionalised polyolefin may be a graft copolymer having a polyolefin backbone grafted with a polyamide (hereinafter termed polyamide graft copolymer). Suitable polyolefins which may be used as the backbone of the polyamide graft copolymer include those listed above as being suitable for use as the backbone of the graft copolymer (ii).

The polyolefin used as the backbone of the polyamide graft copolymer may itself be a graft copolymer in which case the polyolefin is a graft copolymer having a polyolefin backbone grafted with at least one polymerisable ethylenically unsaturated carboxylic acid or derivative thereof. Alternatively, the polyolefin used as the backbone of the polyamide graft copolymer may be grafted with a mixture of a polyamide and at least one polymerisable ethylenically unsaturated carboxylic acid or derivative thereof.

Suitable polymerisable ethylenically unsaturated carboxylic acids and derivatives thereof include those listed above.

The"polyamide"which is graft copolymerised with the polyolefin backbone may be a condensation product which contains recurring amide groups as integral parts of a polymeric chain. These polyamides are well known in the art and are often referred to as Nylons.

The polyamide may be a homopolymer of an aminomonocarboxylic acid, typically having up to 16 carbon atoms inclusive, for example, Nylon 12 or Nylon 6.

Alternatively, the polyamide may be a copolymer of a primary diamine and a dicarboxylic acid and/or derivative thereof (for example, a dicarboxylic acid chloride). The primary diamine is preferably a terminal primary diamine having up to 16 carbon atoms inclusive and at least two carbon atoms between the primary amino groups which are located on terminal carbon atoms of the diamine structure. The diamines suitably contain aromatic moieties linking the amino groups as illustrated by phenylenediamine, 4,4'- diaminobiphenyl and di (4-aminophenyl) ether, or the linking group is cycloaliphatic as in the case of di (4-aminocyclohexyl) methane or 1,4-diaminocyclooctane. The preferred diamines, however, are acyclic terminal primary diamines of the formula, H2N (CH2) nNH2 wherein n is an integer from 2 to 16 inclusive. Such polymethylenediamines include trimethylenediamine, tetramethylenediamine, hexamethylenediamine, decamethylenediamine, dodecamethylenediamine and hexadecamethylenediamine.

The dicarboxylic acid suitably has up to 16 carbon atoms inclusive as illustrated by aromatic dicarboxylic acids such as isophthalic acid, terephthalic acid and 2,6- naphthalenedicarboxylic acid. The preferred dicarboxylic acids, however, are aliphatic dicarboxylic acids, particularly those of the formula, H02C (CH2) mCO2H wherein m is an integer from 0 to 14 inclusive. Illustrative of such dicarboxylic acids are oxalic acid, pimelic acid, sebacic acid, suberic acid, azelaic acid, undecanedioic acid, and adipic acid.

The molecular weight of the polyamide is preferably at least 5,000, most preferably in the range 5,000 to 25,000.

The amount of polyamide which is graft copolymerised with the polyolefin backbone may typically be from 5 to 95%, preferably from 10 to 90%, more preferably from 25 to 80% by weight of the graft copolymer.

Suitable methods for preparing the polyamide graft copolymers are those described above for preparing graft copolymers of a polypropylene and a polymerisable ethylenically unsaturated carboxylic acid or derivative thereof except that it is a polyolefin and a polyamide which are blended or mixed in the presence of a free radical initiator.

The polymer blends of the present invention may comprise more than one

amine-functionalised polyolefin, more than one amide-functionalised polyolefin or a- mixture of one or more amine-functionalised polyolefins and one or more amide- functionalised polyolefins.

Suitably, the amine-functionalised polyolefin or the amide-functionalised polyolefin comprises 1 to 25, preferably 1 to 15, more preferably 2 to 10 %, most preferably 3 to 7, for example, 5 % by weight of the polymer blend.

As noted above, for the purposes of this patent, polyketones are defined as linear polymers having an alternating structure of (a) units derived from carbon monoxide and (b) units derived from one or more olefinically unsaturated compounds. Suitable olefinic units are those derived from C2 to C12 alpha-olefins or substituted derivatives thereof or styrene or alkyl substituted derivatives of styrene. It is preferred that such olefin or olefins are selected from C2 to C6 normal alpha-olefins (straight chain alpha-olefins) and it is particularly preferred that the olefin units are either derived from ethylene or most preferred of all from a mixture of ethylene and one or more C3 to C6 normal alpha- olefin (s) especially propylene or butylene. In these most preferable materials it is further preferred that the molar ratio of ethylene units to C3 to C6 normal alpha-olefin units is greater than or equal to 1 most preferably between 2 and 30. Typically, the polyketone will be a copolymer of ethylene/propylene/CO or ethylene/butylene/CO where the units derived from propylene or butylene are in the range 0.5-10, preferably 5-8% e. g. 6% by weight of the polymer. Blends of two or more polyketones may be used.

The Melt Flow Rate (5kg load at 240°C, 2.095 mm diameter die) is typically in the range 5-200 preferably 10-150, more preferably 20-100, for example 40-80g/lOmins.

The polyketone may suitably have a number average molecular weight of between 10,000 to 1,000,000 preferably between 15,000 and 500,000, more preferably 20,000 and 300,000, most preferably 30,000 and 250,000 A preferred polyketone is an ethylene/propylene/CO terpolymer or an ethylene/butylene/CO terpolymer having a number average molecular weight in the range 60,000 to 150,000.

The blend of the present invention may contain other polymers (for example polyethylene, PVC, polystyrene, polyesters and polyamides; the nature and amount of such a polymer will depend upon what modifications of the polymer properties are required.

As an alternative to using an amine-functionalised polyolefin or an amide-

functionalised polyolefin as a component of the blends of the present invention, it is- envisaged that the polymer blend may comprise: (A) a linear polyketone having an alternating structure of (a) units derived from carbon monoxide and (b) units derived from one or more olefinically unsaturated compounds; (B) polypropylene; (C) a graft copolymer having a polyolefin backbone grafted with 0.001 to 30% by weight of at least one polymerisable ethylenically unsaturated carboxylic acid or derivative thereof ; and (D) a polyamide, wherein component (B) is present in the polymer blend in an amount of above 40% by weight, with the proviso that component (B) is optional when the polyolefin backbone of component (C) is a polypropylene and component (C) is present in the polymer blend in an amount of above 40% by weight.

The term polypropylene, as used for these alternative blends, means an ungrafted polypropylene of the type described above.

Preferably, the alternative blend of the present invention comprises a major proportion of polypropylene (B) and a minor proportion of polyketone (A). Typically, the polypropylene (B) is present in the alternative blend in an amount of at least 50 wt%, more preferably at least 60 wt %, most preferably at least 75 wt %, for example 85 wt %. Preferably the polypropylene is present in the alternative blend in an amount in the range 50 to 90 wt %, more preferably 60 to 90 wt %, most preferably 70 to 90 wt %.

Suitable graft copolymers (C) include those described above which are reacted with compound (D). For avoidance of doubt, the graft copolymers (C) are not reacted with compound (D).

Where the alternative blend of the present invention includes component (B), the graft copolymer (C) may be present in amounts of from 1 to 25 % by weight, preferably 1 to 15 % by weight, based on the total amount of the blend. Where the polyolefin backbone of component (C) is a polypropylene and component (B) is omitted, the polypropylene graft copolymer may be present in an amount of at least 50 wt%, more preferably at least 60 wt %, most preferably at least 75 wt %, for example 85 wt %.

Preferably, the polypropylene graft copolymer is present in the alternative blend in an amount in the range 50 to 90 wt %, more preferably 60 to 90 wt %, most preferably 70

to 90 wt %.

Suitable polyamides (D) include those described above which are graft copolymerised with the polyolefin backbone of graft copolymer (iii). For avoidance of doubt the polyamide is not graft copolymerised with either components (B) or (C) but is blended with components (A), (B) and (C) in the absence of a free radical initiator.

Preferably, components (C) and (D) are blended together prior to blending with components (A) and (B).

The polyamide may be present in the polymer blend in amounts of from 1 to 25% by weight, preferably 2 to 20% by weight based on the total amount of the blend.

The blends of the present invention may contain conventional polymer additives such as, for example, anti-oxidants, stabilisers, impact modifiers, filles, mould release agents, colorants, fire resistant materials and internal or external lubricants.

The polymer blends of the present invention can be prepared using conventional techniques and equipment for batch or continuous blending such as a two-roll mill, a Banbury mixer, or a single/twin screw compounding extruder.

It is to be understood that when in the specification and claims herein, the amounts of the individual components of the polymer blend are expressed in terms of percent by weight, it is meant, unless otherwise indicated, percent by weight based on the total weight of the polymer blend, excluding further components (i. e. further polymers or conventional polymer additives).

The scope of the present invention extends to shaped polymer-based articles (for example, mouldings, pipes, tubes and receptacles such as containers, cups, bowls and trays), and to polymer-based films, sheets, coatings, and liners, wherein the polymer comprises a polymer blend as defined hereinbefore.

Methods of fabricating the blends into articles, films or other applications are standard in the art, for example extrusion, coextrusion, injection moulding, blow- moulding and thermoforming. Preferred methods of fabricating the blends are those where orientation of the polymer is likely e. g. extrusion (film extrusion), blow-moulding and thermoforming.

The shaped polymer-based articles may be made at least in part from a monolayer of the blends of the present invention. Alternatively the articles may be of a multi-layer construction at least one layer of which is a blend according to the present invention.

Where the article is of multi-layer construction, it is preferred that the polyketone/polypropylene blend of the present invention forms an outer-layer of the multi-layer construction, particularly when the outer surface is subjected to abrasion or wear.

According to yet a further aspect of the present invention there is provided a method of improving the scratch resistance of polypropylene which comprises blending a minor proportion of a polyketone with a major proportion of a polypropylene in the presence of an amine-functionalised polyolefin or an amide-functionalised polyolefin wherein the polypropylene is present in the resulting polymer blend in an amount of above 40% by weight.

The invention will now be illustrated by the following Examples.

Materials The materials in the blending experiments were : Polypropylene (PP): Acctuf 3234X supplied by Amoco Chemicals having a melting point (Tm) of 167°C and a melt flow rate (MFR) of 10 g/10 minutes (at 250°C, 2.16 kg load).

Polyketone (PK): an ethylene/propylene/CO terpolymer having a melting point (Tm) of 211°C and a melt flow rate (MFR) of 99 g/10 minutes (at 250°C, 1.2 kg load) compounded with 0.1 % w/w of Irganox 1010 and 1 % w/w of pseudoboehmite.

Amine-functionalised polyolefin (Amine-PO): Paratone 8950 supplied by Exxon Chemical.

The polypropylene (PP), amine-functionalised polyolefin (amine-PO) and polyketone (PK) were dry tumble mixed together in appropriate amounts.

Melt Flow Rate The melt flow rate of the polypropylene and polyketone were determined using a Davenport Melt Indexer fitted with a 2.095 mm diameter die. The test temperature was 250°C and loads of 2.16 kg and 1.2 kg were used respectively.

Blend Preparation Polypropylene/polyketone/amine-functionalised polyolefin blends containing 85% w/w polypropylene, 10% w/w polyketone and 5% w/w amine-functionalised polyolefin were melt processed using a Prism 16mm co-rotating twin screw extruder.

The feed, barrel and die sections of the extruder were set to the following temperatures:

195,210, and 225°C respectively. A screw speed of 200 rpm and a torque of 45% were used throughout production runs.

In addition, a sample of the polypropylene and a polypropylene/polyketone blend (90% w/w polypropylene, 10% w/w polyketone) were also processed under the above conditions.

Blend Characterisation Scanning electron microscopy (SEM) was used to examine the phase structure of the blends and hence the degree of compatibilisation. Samples were prepared by cryo polishing a surface on a pellet of material.

The observations are contained in Table 1.

SEM showed that incorporation of an amine-functionalised polyolefin markedly improves the compatibility of the polyketone and polypropylene components of the blend as evidenced by the greatly reduced, uniform phase sizes. The polyketone was found to be distributed in a polypropylene matrix.

Tensile Properties Tensile properties were measured in accordance with ISO 527-1966 (ASTM D 638M- 93) using compression moulded sheets The test conditions were as follows: 23°C 50% RH (relative humidity); and 50 mm/min (cross head speed).

Measurements were carried out using an Instron Series IX Automated Materials testing system 1.16 machine.

The results of the tensile tests are given in Table 1. The polymer blends according to the present invention had a high tensile elongation to break, a further property associated with good compatibility.

TABLE 1-ENSILE TESTS Experiment Material Composition (wt%) Elongation at break (%) Polyketone Phase Structure (SEM) PK PP Amine-PO Comparative Ex A-100-624 not applicable Comparative Ex B 10 90-135 Irregular, varied phases (0.5-10u. m poiyketone Particles with some up to 105 Rm) Example 1 10 85 5 542 Regular, spherical polyketone phase (approximately 0.5 p. m)