CZ20003076A3 - Compositions of polyolefin-grafted and polyamide grafted copolymers and articles thereof - Google Patents

Abstract

The polymer composition comprises by weight 1) 1% to 98% of a graft copolymer, composed of a propylene polymer forming a backbone to which are grafted monomers selected from a) at least one vinyl aromatic compound and an unsaturated carboxylic acid and b) at least one vinyl aromatic compound and an unsaturated acid anhydride or acid form thereof, wherein the content of polymerized monomers is about 10 to 95 parts per 100 parts of propylene polymer, and 2) 2% to 99% of at least one polyamide resin, the composition also optionally comprising 2% to 30% of at least one rubber component, 5% to 90% of a propylene polymer material with a broad molecular weight distribution, or both.

Description

Compositions of grafted polyolefin copolymers and polyamides, and articles made therefrom

Technical area

This invention relates to compositions consisting of a polyamide resin and a grafted polypropylene copolymer.

State of the art

Compositions of two or more polymers are often prepared in an attempt to combine the desired properties of the individual polymers, to seek unique properties, or to produce a less expensive polymer product by blending cheaper polymer components. Many attempts have been made to blend polyamide resins such as nylon-6 and nylon-6,6 with polyolefin materials. Polyamide resins have excellent chemical and abrasion resistance, good electrical properties, and higher mechanical strength, and are characterized by a good oxygen barrier. However, they are sensitive to moisture and are very difficult to process due to their high melting point. Polypropylene is a low-cost, low-density, semi-crystalline polymer with excellent moisture resistance, recycling, and processability.

However, it is difficult to achieve good dispersion of polar polyamide resin and non-polar polyolefin resin. It is known that by adding a graft or block copolymer of similar chemical structure as the components of the composition, the dispersion quality can be improved. These copolymer additives, generally called compatibilizers, are often added to the compositions as a third component.

Maleic anhydride grafted polypropylene is used as a compatibilizer for polypropylene-nylon compositions. For example, a graft copolymer, which is the reaction product of a styrene/maleic anhydride copolymer and a thermoplastic polymer with functional groups, such as polypropylene, grafted with monomers with carboxyl groups, is added to the polyamide and optionally, to the polypropylene. It is disclosed in U.S. Patent 5,244,971. The styrene copolymer may be composed of styrene and/or alpha-methylstyrene and • · ·

• · « · maleic anhydride and optionally acrylate or methacrylate and/or acrylonitrile. U.S. Patent 5,317,059 discloses polymer compositions comprising 1) at least one olefin polymer, 2) at least one polyamide, 3) a compatibilizer which is at least one terpolymer of an alpha-olefin, an acrylic acid ester and an unsaturated dicarboxylic acid or glycidyl acrylate, and optionally 4) an auxiliary compatibilizer. U.S. Patent 5,665,820 discloses the use of elastomeric polypropylene modified with an unsaturated grafting monomer and/or a composition thereof with isotactic polypropylene modified with an unsaturated grafting monomer as a compatibilizer for polyamide and polyolefin compositions. The grafting monomers used include unsaturated mono- or dicarboxylic acids, or anhydrides or esters thereof, vinyl alcohol esters, vinyl aromatic compounds and compositions thereof. U.S. Patent 5,234,993 discloses compositions of at least one polyamide and a crystalline polyolefin, comprising a compatibilizing rubber polymer, such as ethylene/propylene/diene rubber, grafted with at least one maleic anhydride or glycidyl methacrylate.

However, there is still a need for a material that would provide homogeneous polyamide-polyolefin compositions with improved impact resistance and a better balance between strength and stiffness.

The essence of the invention

The composition according to the present invention consists by weight of:

1) about 1% to 98% of a graft copolymer comprising a polypropylene backbone grafted with monomers selected from the group consisting of a) at least one vinyl aromatic compound and an unsaturated carboxylic acid, and

b) at least one aromatic vinyl compound and an unsaturated carboxylic acid or its anhydride, the polymerized monomers being present in an amount of about 10 to 95 parts per hundred parts of polypropylene, and

2) about 99% to 2% of at least one polyamide resin.

The graft copolymer and polyamide compositions are compatible, easy to process and have good moisture barrier. Articles made from these compositions have good impact resistance and their strength and stiffness are well balanced.

Detailed description of the invention.

The amount of graft copolymer in the composition according to the present invention is about 1% to 98%, preferably about 50% to 90%, based on the total weight of the composition.

The polypropylene material used as the main chain (backbone) of the graft copolymer can be:

1) a homopolymer of propylene, with an isotacticity index greater than 80, preferably around 85 to

99;

2) a copolymer of propylene and an olefin selected from the group consisting of ethylene and an alpha-olefin of 4 to 10 C. Provided that the oleum is ethylene, then the maximum polymerized ethylene content is about 20% by weight, preferably about 16%, the copolymer having an isotacticity index greater than 85;

3) a terpolymer of propylene and two olefins selected from the group consisting of ethylene and an alpha-olefin by 4 to 8 C. Provided that the maximum alpha-olefin content is 20 wt.%, preferably around 16%, and if ethylene is one of the olefins, then the maximum ethylene content is 5 wt.%, preferably around 4%, the terpolymer has an isotacticity index greater than 85;

4) an olefin polymer composition comprising:

a) about 10% to 60% by weight, preferably about 15% to 55%, of a propylene homopolymer, with an isotactic index greater than 80, preferably about 85 to 98, or a copolymer of monomers selected from the group consisting of i) propylene and ethylene, ii) propylene, ethylene and an alpha-olefin of 4 to 8 C, and iii) propylene and an alpha-olefin of 4 to 8 C, the copolymer having a polymerized propylene content greater than 85% by weight, preferably about 90% to 99%, and an isotactic index greater than 85.

b) about 5% to 25% by weight, preferably about 5% to 20%, of an ethylene-propylene copolymer or an alpha-olefin of 4 to 8°C, insoluble in xylene at ambient temperature; and

c) about 30% to 70% by weight, preferably about 40% to 65% by weight of an elastomeric copolymer formed by copolymerizing monomers selected from the group consisting of i) ethylene and propylene, ii) ethylene, propylene and an alpha-olefin of 4 to 8 C, and iii) ethylene and an alpha-olefin of 4 to 8 C. This copolymer optionally contains about 0.5% to 10% by weight of polymerized diene and contains less than 70% by weight, preferably about 10% to 60%, most preferably about 12% to 55% polymerized ethylene. It is soluble in xylene at ambient temperature and has an intrinsic viscosity, measured in tetrahydronaphthalene at 135 °C, of about 1.5 to 4.0 dl/g, φ · · · r • · · * · ♦ · · • » 9 * · · · · · · ♦ · * • ·

5) thermoplastic olefin, containing:

a) about 10% to 60%, preferably about 20% to 50%, of propylene homopolymers, with an isotactic index greater than 80, or a copolymer of monomers selected from the group consisting of i) propylene and ethylene, ii) propylene, ethylene and an alpha-olefin of 4 to 8 C, and iii) propylene and an alpha-olefin of 4 to 8 C. The copolymer has a polymerized propylene content of greater than 85 wt.%, and its isotactic index is greater than 85;

b) about 20% to 60%, preferably about 30% to 50%, of an amorphous copolymer of monomers selected from the group consisting of i) ethylene and propylene, ii) ethylene and propylene and an alpha-olefin of 4 to 8 C, and iii) ethylene and an alpha-olefin of 4 to 8 C, the copolymer optionally containing about 0.5% to 10% polymerized diene, and containing less than 70% polymerized ethylene, being soluble in xylene at ambient temperature; and

c) about 3% to 40%, preferably about 10% to 20% of a copolymer of ethylene and propylene or an alpha-olefin of 4 to 8 C, is insoluble in xylene at ambient temperature, the thermoplastic olefin having a flexural modulus of greater than 150 but less than 1200 MPa, preferably about 200 to 1100 MPa, and most preferably about 200 to 1000 MPa.

Room or ambient temperature is ~25°C.

The 4 to 8 C alpha-olefin useful in the preparation of 4) and 5) includes, for example, butene-1, pentene-1, hexene-1, 4-methyl-1-pentene and octene-1.

If a diene is included in the composition, it is typically butadiene, 1,4-hexadiene, 1,5-hexadiene, or ethylidene norbornene.

Materials based on the propylene polymer 4) and 5) can be prepared by polymerization in at least two stages, where in the first stage propylene and ethylene, propylene and alpha-olefin, or propylene, ethylene and alpha-olefin are polymerized to form component a) of points 4) or 5) and in the following stages mixtures of ethylene and propylene, ethylene and alpha-olefin or ethylene, propylene and alpha-olefin and optionally diene are polymerized to form components b) and c) of points 4) or 5).

«9 9 9 » 9

The polymerization can be carried out in the liquid phase, the gas phase, or the liquid-gas phase, using separate reactors, either batchwise or continuously. For example, it is possible to carry out the polymerization of component a) using liquid propylene as a diluent, and the polymerization of components b) and c) without intermediate steps, except for partial degassing of the propylene. All polymerizations in the gas phase are preferred.

The preparation of the polymer propylene material 4) is described in more detail in U.S. Patents 5,212,246 and 5,409,992, which are incorporated herein by reference. The preparation of the polymer propylene material 5) is described in more detail in U.S. Patents 5,302,454 and 5,409,992, which are also incorporated herein by reference.

Propylene homopolymer is the preferred polymeric propylene material forming the backbone of the copolymers.

Monomers that can be grafted onto the polypropylene backbone are either i) at least one vinyl aromatic compound and an unsaturated carboxylic acid or ii) at least one vinyl aromatic compound and an anhydride of an unsaturated carboxylic acid or an acid form thereof. During graft polymerization, the monomers also copolymerize, forming some amount of free or ungrafted copolymer or terpolymer. The polymerized monomers contain about 10 to 95 parts per hundred parts polypropylene, preferably about 30 to 95 pph. The morphology of the graft copolymer is such that the polypropylene is the continuous or matrix phase, and the polymerized monomers, grafted or ungrafted, are the dispersed phase.

Vinyl aromatic compounds may be substituted or unsubstituted and include, for example, styrene, α-methylstyrene, 4-butylstyrene, 4-tert-butylstyrene, 2-ethylstyrene,

2-methoxystyrene, 4-methoxystyrene, vinylnaphthalene, or any halogenated styrene, such as 2-chlorostyrene and 4-chlorostyrene. Suitable unsaturated carboxylic acids include, for example, acrylic acid, methacrylic acid and maleic acid. Suitable unsaturated carboxylic acid anhydrides include, for example, maleic anhydride, acrylic anhydride, citraconic anhydride and itaconic anhydride.

Preferred monomers include i) styrene and methacrylic acid (S/MAA), ii) styrene and maleic anhydride (S/MA), and iii) styrene, α-methylstyrene and maleic anhydride (S/MS/MA). In the case of S/MAA, the methacrylic acid content is about 10% to 90%, preferably about 10% to 50%, based on the total weight of the monomers. In the case of S/MS/MA, the styrene content is about 5% to 20%, α-methylstyrene is about 5% to 45%, based on the total weight of the monomers. In the case of S/MA, the maleic anhydride content is about 35% to 45%, preferably about 37% to 43%, based on the total weight of the monomers.

« · 9,399

The graft copolymer chain acts as a compatibilizer for the polypropylene and polyamide phases.

Graft copolymers can be prepared in various ways. One of them is the creation of an active grafting site on the polypropylene chain with peroxide or other chemical compounds that are initiators of radical polymerization, or by irradiation with high-energy ionizing radiation. Free radicals formed on the polymer as a result of chemical or radiation treatment create active grafting sites on the polymer and initiate polymerization of monomers at these sites. Graft copolymers prepared by peroxide-initiated grafting processes are more advantageous.

The preparation of graft copolymers of polypropylene and at least one vinyl monomer, carried out by the action of radical polymerization initiators, such as an organic peroxide, is described in more detail in U.S. 5,140,074, which is incorporated herein by reference. The preparation of graft copolymers by irradiation of an olefin polymer and subsequent treatment with at least one vinyl monomer is described in more detail in U.S. 5,411,994, which is also incorporated herein by reference.

Component 2) of the composition according to the invention is at least one polyamide. Suitable polyamides are well known and widely available. In principle, they can be obtained by polymerizing a monoaminomonocarboxylic acid or its lactam, this acid having at least two carbon atoms between the amino group and the carboxyl group. They can also be obtained by polymerizing a substantially equimolecular amount of a diamine containing at least two carbon atoms between the amino groups and a dicarboxylic acid, or by polymerizing a monoaminocarboxylic acid or its lactam as defined above, as well as by polymerizing a substantially equimolecular amount of a diamine and a dicarboxylic acid. The dicarboxylic acids can be used in the form of their functional derivatives, e.g. esters or chlorides.

The term substantially equimolecular portions (diamine and dicarboxylic acid) is used to express precisely equimolecular portions and the slight deviations therefrom that occur in conventional techniques to ensure viscosity stabilization of the resulting polyamides.

Examples of monoamino-monocarboxylic acids or their lactams which are useful for the preparation of polyamides include compounds containing from 2 to 16 carbon atoms between the amino group and the carboxyl group, in the case of lactams the carbon atoms form a ring with the CO-NH- group. Specific examples of aminocarboxylic acids and lactams include, for example, 6-aminocaproic acid, butyrolactam, pivalolactam, caprolactam, capyllactam, enantholactam, undecanolactam. dodecanolactam and 3- and 4-aminobenzoic acids.

Diamines suitable for the preparation of polyamides include alkyl, aryl and alkyl-aryl diamines. Such diamines are, for example, compounds of the general formula:

H ₂ N(CH ₂ ) _n NH ₂ where n is an integer from 2 to 16, such as trimethylenediamine, tetramethylenediamine, pentamethylenediamine, octamethylenediamine and especially hexamethylenediamine, but also trimethylhexamethylenediamine, m-phenylenediamine and m-xylylenediamine.

Dicarboxylic acids can be aromatic, e.g. isophthalic and terephthalic acids, or aliphatic, with aliphatic dicarboxylic acids having the formula:

HOOC-Y-COOH where Y represents a bivalent aliphatic group containing at least 2 carbon atoms. Examples of such acids are sebacic, octadecanedioic, suberic, glutaric, pimelic and adipic acids. Typical examples of polyamides, nylons as they are often called, are, for example:

-polypropylene (nylon 4)

-polycaprolactam (nylon 6)

-polycapryllactam (nylon 8)

-polyhexamethylene adipamide (nylon 6, 6)

-polyundecanolactam (nylon 11)

-polydodecanolactam (nylon 12)

-polyhexamethyleneazelainamide (nylon 6, 9)

-polyhexamethylenesebacamide (nylon 6, 10)

-polyhexamethyleneisophthalamide (nylon 6, 1)

-polyhexamethyleneterephthalamide (nylon 6, T)

-polyamide of hexamethylenediamine and n-dodecanedioic acid (nylon 6,12) and also polyamides derived from terephthalic acid and/or isophthalic acid and trimethylhexamethylenediamine, polyamides derived from adipic acid and m-xylenediamines, polyamides derived from adipic acid, azelaic acid and 2,2-bis(p-aminocyclohexyl)propane and polyamides derived from terephthalic acid and 4,4'-diaminocyclohexylmethane.

Copolymers of the following polyamides or their prepolymers are also suitable for use in the practice of this invention.

Such copolyamides include the following copolymers:

-hexamethylene adipamide/caprolactam (nylon 6, 6/6)

-hexamethylene adipamide/hexamethvlenisophthalamide (nylon 6, 6/6,1)

-hexamethylene adipamide/hexamethylene terephthalamide (nylon 6, 6/6, T)

- hexamethylene adipamide/hexamethylene azelainamide (nylon 6, 6/6, 9)

- hexamethylene adipamide/hexamethylene azelainamide/caprolactam (nylon 6, 6/6,9/6) Compositions and/or copolymers of two or more of the following polyamides or their prepolymers are also of interest in the present invention. Particularly preferred polyamides are polyamides 6; 6,6; 11; 12 and compositions of at least one crystalline polyamide, i.e. 6; 6,6; and at least one amorphous polyamide, i.e. 6, I; 6, I, T; and most preferably polyamide 6, polyamide 11, or polyamide 12.

It is also understood that the term polyamides, as used herein and in the appended claims, also includes toughened and supertough polyamides. Supertough polyamides, or supertough nylons as they are more commonly known, are commercially available, i.e., from E.I. du Pont de Nemours and Company (Zytel ST resins), Wilson Fiberfille (NY resins), Badische Aniline and Sodafabrik (Ultramid resins), among others, or can be prepared according to U.S. patents, including, but not limited to, U.S. patents 4,174,358; 4,474,927; 4,346,194 and 4,251,644, which are incorporated herein by reference. These supertough nylons are prepared by blending one or more polyamides with one or more polymeric or copolymeric elastomeric reinforcing additives. Suitable reinforcing additives are disclosed in the U.S. patents mentioned above, as well as in U.S. patents 3,884,882 and 4,147,740 and in Galucci et.al., Preparation and Reactions Epoxy-Modified Polyethylene, J.Appl.Poly.Sci., 27, 425-437 (1982), which are incorporated herein by reference.

These elastomeric additives can typically be straight-chain or branched polymers and copolymers, but also grafted polymers and copolymers, including core-shell grafted copolymers. They are characterized by having incorporated into the pre-prepared polymer, by copolymerization or grafting, a monomer with functional and/or active or highly polar groups that are capable of interacting with or attaching to the polyamide matrix, thereby increasing the toughness of the polyamide.

The polyamide content in the composition is about 99% to 2%, preferably about 50% to 10%, based on the total weight of the composition.

The compositions may also optionally comprise about 2% to 40%, preferably about 5% to 30%, based on the total weight of the composition, of one or more rubber components and/or about 5% to 90%, preferably about 10% to 70%, based on the total weight of the composition, of a polypropylene material, with a broad molecular weight distribution. The rubber component is selected from one or more of the groups consisting of i) an olefin copolymer rubber, ii) a block copolymer based on a monoalkenyl aromatic hydrocarbon and a conjugated diene, and iii) an encapsulated rubber. Any of these rubber components may have an acid or anhydride functionality, or may be without them. Preferred rubber components are ad i) or ad ii), either alone or in combination.

Suitable olefin copolymer rubbers include, for example, saturated olefin copolymer rubbers such as ethylene/propylene monomer rubbers (EPM), ethylene/octene-1 and ethylene/butene-1 rubbers and unsaturated olefin copolymer rubbers such as ethylene/propylene/diene monomer rubbers (EPDM). Preferred olefin copolymer rubbers are ethylene/propylene, ethylene/butene-1 and ethylene/octene-1 copolymers.

The monoalkenyl aromatic hydrocarbon - conjugated diene block copolymer may be a thermoplastic elastomer of the AB (or diblock) structure, the linear ABA (or triblock) structure, the radial (AB) _n type, where n = 3 to 20%, or a combination of these structural types, each A block being a monoalkenyl aromatic hydrocarbon polymer block, each B block being an unsaturated rubber block. Various types of copolymers of this type are commercially available. The individual types differ in structure, molecular weight of the middle and end blocks, and in the ratio of monoalkenyl aromatic hydrocarbon to rubber. The block copolymer may also be hydrogenated. Typical monomers based on monoalkenyl aromatic hydrocarbons are: styrene, ring-substituted 1 to 4 C linear or branched alkylstyrenes, and vinyltoluene. Styrene is preferred. Suitable conjugated dienes include, for example, butadiene and isoprene. Preferred block copolymers are triblock copolymers: hydrogenated styrene/ethylene - butene-1/styrene.

The weight average molecular weights (M _w ) of the block copolymers are generally in the range of about 45,000 to 260,000 g/mol, with average molecular weights in the range of about 50,000 to 125,000 g/mol being preferred because they provide compositions with the best balance between toughness and stiffness. Although block copolymers with both unsaturated and saturated rubber blocks can be used, copolymers with saturated rubber blocks are preferred, also because of the better balance between toughness and stiffness of such compositions. The weight ratio of monoalkenyl aromatic hydrocarbon to conjugated diene rubber in the block copolymer is in the range of about 5/95 to 50/50, preferably about 10/90 to 40/60.

Encapsulated rubber components comprise small particles of a crosslinked rubber phase surrounded by a compatibilizing shell, usually of a glassy polymer or copolymer. The core is typically a diene rubber, such as butadiene or isoprene, or a polyacrylate. The shell is typically a polymer of two or more monomers, such as styrene, methyl methacrylate, and acrylonitrile. Particularly preferred encapsulated rubbers have a polyacrylate core.

Suitable rubbers useful as toughness modifiers include, for example, Engage 8150 ethylene/octene-1 copolymer, commercially available from DuPont-Dow Elastomers; EPM 306P ethylene/propylene copolymer, commercially available from Polysar Rubber Division of Miles, Incorporated; and Kraton RP 6912, a styrene/ethylene propylene/styrene triblock copolymer rubber, and Kraton FG 1901X, a styrene/ethylene butene-1/styrene triblock copolymer rubber, modified with maleic anhydride, commercially available from Shell Chemical Company.

Preferred rubbers are 1) maleic anhydride-modified monoalkenyl aromatic hydrocarbon-conjugated diene block copolymers, 2) a combination of a maleic anhydride-modified monoalkenyl aromatic hydrocarbon-conjugated diene block copolymer and an unmodified monoalkenyl aromatic hydrocarbon-conjugated diene block copolymer, 3) a combination of a maleic anhydride-modified monoalkenyl aromatic hydrocarbon-conjugated diene block copolymer and an olefin copolymer-based rubber, or 4) a combination of a maleic anhydride-modified monoalkenyl aromatic hydrocarbon-conjugated diene block copolymer and an unmodified monoalkenyl aromatic hydrocarbon-conjugated diene block copolymer and an olefin copolymer-based rubber.

Another optional additive is a broad molecular weight distribution polypropylene material (BMWD PP) with a ratio of M,M of about 5 to 60, preferably about 5 to 40; a melt flow index of about 0.5 to 50, preferably about 1 to 30 g/10 min, a xylene insolubility at 25°C of greater than or equal to 94%, preferably greater than or equal to 96%, and most preferably greater than or equal to 98%. The broad molecular weight distribution polypropylene material may be a propylene homopolymer or an ethylene/propylene rubber, a toughness modified propylene homopolymer, wherein the propylene homopolymer has a broad molecular weight distribution.

BMWD PP is prepared by sequential polymerization in two stages, in the presence of a Ziegler-Natta catalyst, supported by magnesium halide in active form. The polymerization takes place separately and sequentially, and in each stage in the presence of the polymer and catalyst from the previous stage.

The polymerization can be carried out batchwise or continuously by known techniques, in the liquid phase, in the presence or absence of an inert solvent, or in the gas phase, or in the liquid-gas phase, preferably in the gas phase. The preparation of BMWD PP is described in more detail in U.S. Patent 5,286,791, which is incorporated herein by reference.

The composition according to the invention may also comprise a) an inorganic filler, such as CaCO ₃ , talc or silicate, b) reinforcing glass fibres, or c) a composition of a) and b). If these fillers are present in the composition, the amount of a) and/or b) is about 5% to 50%, preferably about 10% to 30%, based on the total weight of the composition.

A binder is generally used with glass fibers. The binder may be, for example, polypropylene modified with an α, β-unsaturated carboxylic acid or an alicyclic carboxylic acid and their derivatives, such as acrylic, methacrylic, maleic, fumaric, itaconic, endocyclo (2,2,1)-5-heptene-2,3-carboxylic acid and cis-4-cyclohexene-1,2-carboxylic acid and their anhydrides, esters, amides and imides.

Polypropylenes modified with varying amounts of maleic anhydride or maleic acid are preferred and are commercially available, e.g., from Eastman Chemical Company and Aristech Chemicals. Modified polypropylenes generally contain about 0.5% to 10% maleic acid or maleic anhydride, based on the total weight of the modified polymer. The binder is used in an amount of about 0.5% to 7%, preferably about 1% to 5%, based on the total weight of the composition.

The composition may also optionally contain about 1% to 10%, preferably about 2% to 5%, based on the total weight of the composition, of an auxiliary compatibilizing agent when glass fibers are not present in the mixture. Suitable auxiliary compatibilizing agents include modified polypropylenes, as described above in the binders section.

Optionally, the composition may also contain additives to improve abrasion and wear resistance. These additives may be a) at least one low molecular weight polyethylene or a functionalized derivative thereof, and b) a combination of at least one of the low molecular weight polyethylenes in a) and inorganic microspheres.

Low molecular weight polyethylene has a number average molecular weight (M n ) of about 300 to 5000. Functionalized derivatives of these polyethylenes, such as hydroxylated or ethoxylated derivatives, or their phosphate esters, or derivatives of primary carboxylic acids, or linear polyethylenes grafted with maleic acid, can also be used. The content of polyethylenes in the composition is about 0.5% to 10%, preferably about 2% to 5%, based on the total weight of the composition.

The additive may also be a combination of about 0.5% to 10% of the low molecular weight polyethylene described above and about 0.5% to 10%, preferably about 1% to 5%, based on the total weight of the composition, of inorganic microspheres. The inorganic microspheres may be, for example, a ceramic alloy of silica and alumina, an alkali aluminosilicate ceramic or glass, and may be coated with a sizing agent such as an aminosilane. Modified polypropylene, as described in the article on binders, may also be used in conjunction with the inorganic microspheres, and then act as a binder and co-compatibilizer.

Other additives, such as pigments, lubricants, waxes, oils, anti-blocking agents, antioxidants, and polysiloxanes such as poly(dimethylsiloxane), may also be part of the composition.

The compositions of the present invention can be made into articles by methods known in the art, such as, for example, injection molding, molding, extrusion of profiles, extrusion of films, and blow molding.

The test methods used to evaluate the manufactured samples were as follows:

- Izod notched impact strength ASTM-D-256 (0.907 kg hammer)

- tensile strength at yield point ASTM-D-638-89 (shear rate @ 5.08 cm/min) flexural strength at yield point E-modulus in flexure (1% secant) elongation at break elongation at yield point Shore D hardness hot dimensional stability HDT E-modulus in tension

ASTM-D-790 @0.127 cm/min. ASTM-D-790 @ 0.127 cm/min. ASTM-D-638-89

ASTM-D-638-89

ASTM-D-2240

ASTM-D-648

5.08 cm/min.

ASTM-D-638-89,

The isotacticity index is defined as the % solubility in xylene. The weight percent solubility of an olefin polymer in xylene at room temperature is determined by dissolving

2.5 g of polymer in 250 ml of xylene at room temperature, in a vessel equipped with a stirrer, by heating it to 135 °C with stirring for 20 minutes. The solution is cooled to 25 °C with constant stirring, then left without stirring for 30 minutes to allow the solid particles to settle. The precipitate is filtered off with filter paper, the remaining solution is evaporated in a stream of nitrogen and the solid is dried under vacuum at 80 °C until constant weight. The weight percentage, • · · · · · · · · · · insoluble in xylene at room temperature, is the isotactic index of the polymer. The value obtained in this way essentially corresponds to the isotactic index determined by extraction in boiling n-heptane, which by definition determines the isotactic index of the polymer.

Intrinsic viscosity is measured in tetrahydronaphthalene at 135 °C.

The porosity of propylene homopolymers, used as the backbone polymer in the preparation of graft copolymers in the examples, is described in the articles by Winslow, N.M. and Shapiro, J.J., An Instrument for the Measurement of Pore-Size Distribution by Mercury Penetration, ASTM Bull.jTP 49, 39-44 (Feb.1959), and Rootare, H.M,Eds., Advances Experimental Techniques in Powder Metallurgy, Plenum Press, New York, 1970.

Abrasion and wear resistance were measured using Ford Laboratories test method BN 108-13 (Abrasion Resistance). The apparatus consists of a number of weighted tips that contact the test specimens. The tips used for the abrasion test were tipped with highly polished steel balls with a diameter of 1.0 mm and the diameter of the tip balls for the wear test was 7.0 mm. The tips were loaded with different weights, exerting the following standard forces on the surface of the test material: 2.0 newtons (N); 3.0 N; 4.5 N; 6.0 N; 7.0 N. The tips were then dragged across the test plate. All scratches were examined and rated on a scale of 1 to 5, with 1 = no scratch at all and 5 = severe scratch. Better values achieved, compared to the comparison experiment, were the criterion for an acceptable test result. A black pigmented test specimen was used because experience has shown that a black surface is easier to observe with the naked eye than surfaces of other colors.

All surface gloss readings were taken on a 20 degree gloss meter on a smooth (unscratched) sample.

The Chrysler crocking gloss test was conducted according to Chrysler Laboratory Procedure LP-463PB-54-01, using an Atlas AATCC Mar Tester, Model CM-5. Bon-Ami dry cleaner was applied to one half of a 4" x 6" molded test plate. The cylindrical acrylic finger of the Mar Tester was covered with 2" x 2" green felt 14-9956-000, commercially available from Atlas Electric Devices Co. The cleaner-covered plate was smoothed with a wool felt ten times (ten double strokes). The 20° gloss was measured at several locations on the worn and unworn surfaces of the plate. The maximum gloss value on the unworn surface was designated as the original gloss. The minimum gloss on the worn • · · · » . · · · · · ’ • · · · · · .......

»** . · · · · · «··· ·· ..... ·· the surface was designated as the gloss after wear. The gloss retention in %, i.e. the % wear resistance, was calculated from the gloss value after wear divided by the original gloss value x 100.

The Ford crocking gloss test was conducted in accordance with Ford Laboratory Procedure Bl 161-01, Determination of Abrasion Resistance of Automotive Paints, using an Atlas A ATCC Mar Tester, Model CM-5. A square of 281Q Wetordry Production Polishing Paper, 50 mm x 50 mm, commercially available from Minnesota Mining and Manufacturing Company (the standard grade 3 pm is better than the 2 pm grade), was placed on a similar sized green felt 14-9956-000, commercially available from Atlas Electric Devices Co., with the abrasive side of the polishing paper facing out. The two squares were wrapped around and secured around the finger of the instrument so that the felt was between the finger and the polishing paper. The instrument had a cylindrical acrylic, brass or wooden finger with a diameter of 16 mm and exerted a force of 9 N on the test surface and the stroke was approximately 100 mm long. After measuring the 20° gloss of the test surface, 10 double strokes were made on the surface in the wear test. The 20 ^° gloss of the abraded surface was measured in a direction parallel to the abrading strokes of the Mar tester and the lowest reading was recorded. The gloss retention in %, i.e. the wear resistance, is the 20° gloss of the abraded surface divided by the original 20° gloss x 100.

In this specification, all quantities are given in parts by weight or percentages unless otherwise stated.

Examples of embodiments of the invention

Example 1

This example describes the effect of nylon-6 and a toughness modifier on the properties of a graft copolymer comprising a propylene homopolymer backbone grafted with a styrene-methacrylic acid copolymer (PP-g-(S/MAA)). A comparison was also made with a compatibilizer composition based on polypropylene grafted with maleic anhydride but without the grafted PP-g(S/MAA) copolymer.

In this and the following examples, the propylene homopolymer used as the backbone polymer had the following properties: spherical shape, melt flow index (MFR) of 10 dgmin at 230°C and 2160 g, porosity of 0.44 cc/g, xylene insolubility of 96.5% at room temperature, and Mw/Mn =5.

Monomers (60/40 styrene/methacrylic acid) were grafted onto polypropylene at 100 °C using the previously described graft polymerization procedure initiated by peroxides. 95 parts by weight of monomers were added to 100 parts of polypropylene. Tert-butyl peroxy-2-ethylhexanoate (2.1 parts of active peroxide per 100 parts of polypropylene, 50% solution in light gasoline) was used as the peroxidic initiator. Styrene and methacrylic acid were premixed and dosed at a rate of 1.0 pph/min for 95 minutes. The initiator was added in a ratio to monomer (M/I) of 100/1. After the addition of the monomers was complete, the temperature was maintained at 100 °C for another 30 minutes and then increased to 140 °C for 90 minutes in a pure nitrogen atmosphere.

The graft copolymer was then blended with the materials listed in Table 1. All polymers were used without drying, except for the polyamide, which was oven-dried with a desiccant at 80°C overnight or at least 3 hours before blending. All materials were dry-blended and bag-mixed with 0.2% by weight of the antioxidant Irganox B225 and 0.1% by weight of calcium stearate prior to extrusion. The amounts of each material are given in Table 1.

Broad molecular weight distribution polypropylene (BMWD PP) had a melt flow index of 1.1 dg/min, 97.8% xylene insolubility, and Mw/Mi > 6 and is commercially available from Montell USA Inc. Sufficient BMWD PP was added to each sample to provide an effective level of polymerized monomer, 30 parts per 100 parts polypropylene.

The polyamide was polycaprolactam Capron 8202 NL, commercially available from Allied Signal, Inc. The polyamide had a melt index of 34.2 (3.8 kg, 230°C).

The propylene homopolymer in Comparative Example 3 was the same as the polymer used as the backbone polymer for the graft copolymer.

The toughness modifier of S-EB-S-g-MA was Kraton FG1901X, a styrene/ethylenebutylene/styrene maleic anhydride-grafted triblock copolymer containing ~2 wt% maleic anhydride and commercially available from Shell Chemical Company. The compatibilizer was maleated polypropylene (PP) Unité MP 1000 polypropylene, commercially available from Aristech Chemical Corporation.

Irganox B225 antioxidant is a mixture of 1 part of the stabilizer Irganox 1010 - tetrakis[methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate)] methane and 1 part of the stabilizer Irgafos 168 tri-(2,4-di-t-butylphenyl)phosphite, and is commercially available from Ciba Specialty Chemicals Corporation.

The sample material was prepared by mixing on a 34 mm Leistritz twin-screw extruder at a temperature of 245 °C, a screw speed of 300 rpm and an output of 11.325 kg/h. After extrusion, the granules were dried in a desiccator at 80 °C for at least 2 to 4 hours before further processing.

The test specimens were injected on a 142 g Battenfeld injection molding machine. The mechanical properties were measured after conditioning for 48 hours at 50% relative humidity and 23 °C. The results are shown in Table 1.

Table 1 Sample 1 2 3 Cf.l Cf.2 Cf.3 PP-g-(S/MAA) (wt%) 38 33 31 48 43 - BMWD PP (wt%) 42 37 34 52 47 34 Propylene homopolymer (wt%) - - - - - 31 S-EB-S-g-MA (wt%) - 10 10 - 10 10 Polyamide (wt%) 20 20 25 - - 20 Antioxidant (wt%) 0.2 0.2 0.2 0.2 0.2 0.2 Calcium stearate (pph) 0.1 0.1 0.1 0.1 0.1 0.1 Maleated PP (wt%) - - - - - 5 Izod Notch Strength (J/cm) 0.4 1.2 1.0 0.27 0.48 2.0 Tensile yield strength (MPa) 54.2 42.7 46.3 39.4 35.4 32.5 Bending yield strength (MPa) 76.8 61 64.8 61.5 49.3 35.8 Flexural modulus, 1% secant (MPa) 2277 1808 1884 2153 1677 1159 Elongation at break (%) 4 29 24 6.5 42.5 85 Elongation at yield point (%) 4 5 4.4 4.6 7 9.6

The data show an increase in tensile strength and a good balance of impact strength and stiffness for samples containing the grafted polyamide-polypropylene copolymer -S/MAA. The compatibility of the composition is indicated by its stable morphology, high gloss and good surface appearance.

• · · ·

Example 2

This example describes the effect of nylon-6 and toughness modifiers on the properties of a graft copolymer consisting of a propylene homopolymer backbone grafted with a styrene/alpha-methylstyrene/maleic anhydride (S/MS/MA) copolymer. A comparison was also made with a composition containing a compatibilizer, maleic anhydride grafted polypropylene, but no grafted PP-g-(S/MS/MA) copolymer.

Monomers (19.4% styrene, 44% alpha-methylstyrene, 36.5% maleic anhydride) were grafted onto polypropylene at 90°C using the previously described peroxide-initiated graft polymerization procedure. 95 parts by weight of monomers were added per 100 parts of polypropylene. Tert-butyl peroxypivalate (1.5 pph of active peroxide, 75% in light gasoline) was used as the peroxide. The monomers were fed at a rate of 1 pph/min for 95 minutes. Maleic anhydride was melted and fed at a rate of 1 pph/min for 95 minutes. The monomer to initiator ratio (M/I) was 100:1. After the addition of the monomers was complete, the temperature was maintained at 90 °C for 30 minutes, then it was increased to 140 °C and maintained for another 30 minutes without the presence of nitrogen. Finally, the polymer was dried for 180 minutes at 140 °C under pure nitrogen.

The graft copolymer was mixed with the materials listed in Table 2 using the procedure described in Example 1.

BMWD PP, propylene homopolymer, polyamide, toughness modifier, maleated polypropylene and antioxidant were the same as in Example 1.

The samples were prepared by mixing on an extruder, after extrusion the granulate was dried and the test specimens were extruded in the manner described in Example 1. The results of the mechanical properties measurements are summarized in Table 2.

Table 2 Sample 1 2 3 Cf.l Cf.2 Cf.3 PP-g-(S/MAA) (wt%) 38 34 27 49 44 - BMWD PP (wt%) 42 36 28 51 46 34 Propylene homopolymer (wt%) - - - - - 31 S-EB-S-g-MA (wt%) - 10 15 - 10 10 Polyamide (wt%) 20 20 30 - - 20 Antioxidant (wt%) 0.2 0.2 0.2 0.2 0.2 0.2 Calcium stearate (pph) 0.1 0.1 0.1 0.1 0.1 0.1 Maleated PP (wt%) - - - - 5 Izod Notch Strength (J/cm) 0.17 0.91 1.0 0.24 0.8 2.0 Tensile yield strength (MPa) 40.6 34.4 35.4 37.6 31.3 32.5 Bending yield strength (MPa) 63.3 48.7 48.6 54.2 43.9 35.8 Flexural modulus, 1% secant (MPa) 2132 1504 1401 1863 1553 1159 Elongation at break (%) 4.3 33 28 10 26 85 Elongation at yield point (%) 3.9 6.14 5.2 5.3 5.6 9.6

The data show an increase in tensile strength and a good balance between impact strength and stiffness for samples containing polyamide and polypropylene S/MS/MA graft copolymer.

Example 3

This example describes the effect of the molar ratio of styrene/methacrylic acid (S/MAA) in the graft copolymer on the properties of a graft copolymer composition with polyamide, BMWD PP and rubber.

The graft copolymers were prepared as in Example 1. They were mixed with the materials listed in Table 3, according to the procedure described in Example 1.

BMWD PP, polyamide, toughness modifier and antioxidant were identical to Example 1.

• · • · • ·

The samples were prepared by mixing on an extruder, after extrusion the granulate was dried, the injection molding of the test specimens was carried out as described in Example 1. The results of the measurement of mechanical properties are summarized in Table 3. The abbreviation used is N.Y. = no yield.

Table 3 Sample 1 2 3 4 5 6 Molar ratio of monomers (S/MAA) 80/20 70/30 60/40 50/50 40/60 20/80 PP-g-(S/MAA) (wt%) 34 34 34 34 34 34 BMWD PP (wt%) 36 36 36 36 36 36 S-EB-S-g-MA (wt%) 10 10 10 10 10 10 Polyamide (wt%) 20 20 20 20 20 20 Antioxidant (wt%) 0.2 0.2 0.2 0.2 0.2 0.2 Calcium stearate (pph) 0.1 0.1 0.1 0.1 0.1 0.1 Izod Notch Strength (J/cm) 1.1 0.91 1.2 0.48 0.21 0.21 Tensile yield strength (MPa) 29 36 42.7 46.9 41.7 38.5 Bending yield strength (MPa) 42 49.3 61 63 64.2 56.5 Flexural modulus, 1% secant (MPa) 1415 1518 1808 1808 1842 1732 Elongation at break (%) 80 61 29 11.4 3.1 3.4 Elongation at yield point (%) 15 8.7 5 4.4 N.Y N.Y.

The data show that a molar ratio of 60/40 S/MAA provides the best balance of properties. Increasing the MAA content above 50 mol% results in a brittle graft copolymer-polyamide composition.

Example 4

This example describes the effect of using different polyamides on the mechanical properties of a grafted copolymer composition of PP-g-(S/MAA), BMWD PP and rubber.

The graft copolymer was prepared as in Example 1. BMWD PP, rubber and antioxidant were described in Example 1.

Nylon-12 was Grilamide L25W40NZ844 polyamide, commercially available from EMS-American Grilon lne. Nylon-11 was Grilamide L25W40X polyamide, commercially available from EMSAmerican Grilon lne. Nylon-6,6 was Zytel 101 polyamide, commercially available from E.I.du • ·

Pont de Nemours & Co. Nylon 6/6,6 copolymer was polyamide Xtraform 1539F, commercially available from AlliedSignal, Inc. The toughness modified nylon-6 was polyamide Capron 8351, commercially available from AlliedSignal, Inc.

The samples were compounded, after extrusion the granules were dried and the injection molding of the test specimens was carried out as described in Example 1. The results of the measurement of mechanical properties are given in Table 4. All compositions excel in good compatibility and processability.

Table 4 Sample 1 2 3 4 5 PP-g-(SZMAA) (wt%) 31 31 31 31 31 BMWD PP (wt%) 34 34 34 34 34 S-EB-S-g-MA (2% MA) (wt%) 10 10 10 10 10 Nylon-12 (wt%) 25 - - - - Nylon-11 (wt%) - 25 - - - Nylon-6.6 (wt%) - 25 - - Nylon-6/6.6 Copolymer (wt%) - - - 25 - Nylon-6 with modified hardness (wt%) - - - - 25 Antioxidant (wt%) 0.2 0.2 0.2 0.2 0.2 Calcium stearate (pph) 0.1 0.1 0.1 0.1 0.1 Izod Notch Strength (J/cm) 2.3 1.1 0.96 1.1 1.0 Tensile yield strength (MPa) 36.7 41 24.9 25.6 34.2 Bending yield strength (MPa) 47.3 51.8 39.8 25.6 34.2 Flexural modulus, 1% secant (MPa) 1408 1594 1221 1118 1346 Elongation at break (%) 100 45 50 79 52 Elongation at yield point (%) 5.6 6 3.4 4 9

In all cases, the compositions excelled with a good balance of properties and good processability.

Example 5

This example describes the effect of changing the amount of toughness modifiers on the mechanical properties of a grafted copolymer composition of PP-g-(S/MAA) and polyamide.

• · ·*·· · · · · · · · · *

The graft copolymer was prepared as described in Example 1.

BMWD PP, polyamide, toughness modifier and antioxidant were the same as in Example 1.

The samples were prepared by mixing on an extruder, after extrusion the granulate was dried and the injection moldings of the test specimens were prepared as described in Example 1. The results of the mechanical properties measurements are given in Table 5.

Table 5 Sample 1 2 3 4 PP-g-(S/MAA) (wt%) 32.5 31 30.5 29 BMWD PP (wt%) 35 34 32 31 S-EB-S-g-MA (wt%) 2.5 5 7.5 10 Polyamide (wt%) 30 30 30 30 Antioxidant (wt%) 0.2 0.2 0.2 0.2 Calcium stearate (pph) 0.1 0.1 0.1 0.1 Izod Notch Strength (J/cm) 0.48 0.53 0.53 0.8 Tensile yield strength (MPa) 52.6 48.3 46.5 43.2 Bending yield strength (MPa) 71.7 64.2 62.4 55.5 Flexural modulus, 1% secant (MPa) 2070 1898 1808 1594 Elongation at break (%) 15 14 24 30 Elongation at yield point (%) 4.6 4.3 4.7 5.4

The data shows that impact strength improves with the addition of toughness modifier, but tensile strength and modulus decrease.

Example 6

This example describes the effect of using different combinations of maleate and non-maleate rubber on the mechanical properties of a grafted copolymer PP-g-(S/MAA) and polyamide composition.

The graft copolymer was prepared according to Example 1. The graft copolymer was then blended with the materials listed in Table 6 as described in Example 1.

BMWD PP, polyamide and antioxidant were the same as in Example 1.

• · • · · · · · • · · · · · « * · · · · • · · · · ·

The S-EB-S-g-MA rubber was the same as in Example 1. The SEBS rubber was Kraton G1652, a styrene/ethylene/butylene-styrene triblock copolymer, having a styrene/rubber ratio of 29/71 and commercially available from Shell Chemical Company. The ethylene-octene rubber was Engage 8100, an ethylene-octene metallocene rubber, commercially available from DuPont Dow Elastomers.

The samples were prepared by mixing on an extruder, after extrusion the granulate was dried and the test specimens were prepared as described in Example 1. The results of the mechanical properties measurements are given in Table 6.

Table 6 Sample 1 2 3 4 PP-g-(SZMAA) (wt. %) 29 29 26 26 BMWD PP (wt%) 31 31 29 29 S-EB-S-g-MA (wt%) 20 15 20 15 SEBS (wt%) - - - 5 Ethylene-octene rubber (wt%) - 5 - - Polyamide (wt%) 20 20 25 25 Antioxidant (wt%) 0.2 0.2 0.2 0.2 Calcium stearate (pph) 0.1 0.1 0.1 0.1 Izod Notch Strength (J/cm) 6.9 6.4 5.4 8.5 Tensile yield strength (MPa) 31.1 29.8 32.2 32.1 Bending yield strength (MPa) 38 37 39.3 38.7 Flexural modulus, 1% secant (MPa) 1180 1208 1173 1180 Elongation at break (%) 97 141 190 115 Elongation at yield point (%) 12.5 12.6 11.2 12.2

The data show that both maleate and non-maleate toughness modifiers improve the impact strength of PP-g-(S/MAA)/polyamide composites. The strength increases with increasing polyamide content.

• ♦

Example 7

This example describes the effect of water absorption on the tensile strength and modulus of a composite of grafted PP-g-(S/MAA) copolymers, BMWD PP, rubber and polyamide, compared to polyamide alone.

The graft copolymer was prepared according to Example 1. The graft copolymer was then blended with the materials listed in Table 7 as described in Example 1.

The BNWD PP, polyamide, toughness modifier and antioxidant were the same as in Example 1.

The samples were prepared by mixing on an extruder, after extrusion the granulate was dried and the test specimens were extruded as described in Example 1. The results of the mechanical properties measurements are given in Table 7. In Table 7, the abbreviations mean: DAM = drying of test specimens, and Condic. - conditioning with water, i.e. the tests were performed only after 7 days of storage in water at 23 °C.

Table 7 Sample 1 2 3 4 5 6 DAM Water DAM Water DAM Water Condition. Condition. Condition. PP-g-(SZMAA) (wt%) 32.5 32.5 34 34 - - BMWD PP (wt%) 35 35 36 36 - - S-EB-S-g-MA (hxnotn.%) 2.5 2.5 10 10 - - Polyamide (wt%) 30 30 20 20 100 100 Antioxidant (wt%) 0.2 0.2 0.2 0.2 - - Calcium stearate (pph) 0.1 0.1 0.1 0.1 - - Izod Notch Strength (J/cm) 0.48 - 0.91 - 0.75 - Tensile yield strength (MPa) 53.4 49 40.6 37.7 78.4 40.6 Tensile modulus of elasticity (MPa) 2346 2277 1932 1863 2946 1497 Flexural modulus, 1% secant (MPa) 2180 - 1829 - 2760 - Elongation at break (%) 7.5 9.0 70 55 88 283 Elongation at yield point (%) 4.3 4.1 6.1 6.6 4.2 22 Shore D hardness 65 - 60 - 72 - HDT test body 3 mm, 1820 kPa (°C) 58 - 56 - 56 - Water absorption, 7 days, 23 °C (wt%) - 0.41 - 0.32 4.1

The data show that PP-g-(S/MAA)/polyamide compositions absorb very little moisture, the mechanical properties do not deteriorate in the presence of moisture, and the flexural modulus is better than that of water-conditioned polyamide.

Example 8

This example describes the effect of using various additives on improving the abrasion and wear resistance of a grafted copolymer PP-g-(SZMAA) and polyamide composition containing BMWD PP and rubber with and without maleated polypropylene as a compatibilizer or binder.

The graft copolymer was prepared according to Example 1. It was blended with the materials listed in Table 8 as described in Example 1.

BMWD PP, rubber, antioxidant, maleated polypropylene and polyamide were described in Example 1.

The polyethylene wax was Polywax 3000 polyethylene, a fully saturated homopolymer, with a melting point of 129°C and a number average molecular weight (M _n ) of 3000, commercially available from Baker Petrolite, Polymers Division. The polysiloxane was polydimethylsiloxane MB50-001, commercially available from Dow Corning.

The ceramic microspheres were X-292 Zeeospheres, a ceramic alloy of silica and alumina in which 90% by volume of the sample had a particle size of <5.0 to 6.2 µm, treated with Union Carbide A 1100 sizing agent.

The samples were prepared by mixing on an extruder, after extrusion the granulate was dried and the test specimens were extruded as described in Example 1. The results of the measurements of mechanical properties and abrasion and wear tests are given in Table 8.

Table 8 Sample 1 2 3 4 5 6 PP-g-(SZMAA) (wt%) 26 24 24 20.7 21 20 BMWD PP (wt%) 27 26 26 22.3 23 22 S-EB-S-g-MA (wt%) 22 22 22 22 22 22 Polyamide (wt%) 25 25 25 25 25 25 Maleated PP (wt%) - - - 5 5 5 Polyethylene wax (wt%) - - 3 3 3 3 Polysiloxane (wt%) - 3 - - 1 1 Ceramic microspheres (wt%) - - - 2 - 2 Antioxidant (wt%) 0.2 0.2 0.2 0.2 0.2 0.2 Calcium stearate (pph) 0.1 0.1 0.1 0.1 0.1 0.1 Izod Notch Strength (J/cm) 3.2 1.6 5.3 3.7 8.5 3.2 Tensile yield strength (MPa) 34 32.2 30.3 27.8 26.6 26.5 Bending yield strength (MPa) 41.2 32.2 34.7 31.9 30.7 30.5 Flexural modulus, 1% secant (MPa) 1035 1159 1042 959 925 932 Elongation at break (%) 150 81 342 112 135 125 Elongation at yield point (%) 12 7.4 13 17 25 28 Ford 5 fingers- abrasion (2,3,4,5,6,7 N) 34555 13345 23345 23455 23444 23345 Ford 5 fingers - wear (2,3,4,5,6,7 N) 34555 11111 11222 11111 11111 11111 Ford crocking (initial shine) 80 84 85 79 86 70 Chrysler crocking (initial shine) 80 84 85 78 84 71

All compositions containing polyethylene wax, polysiloxane, a combination of polyethylene wax and ceramic microspheres, or a combination of polyethylene wax, polysiloxane and ceramic microspheres were characterized by significantly greater resistance to abrasion and wear and overall better mechanical properties than compositions without additives preventing abrasion and wear.

• ·· ·

Example 9

This example describes the effect of using various additives to improve the abrasion and wear resistance of a PP-g-(S/MAA) graft copolymer and polyamide composition containing BMWD PP, one or two rubber components and maleated polypropylene as an auxiliary compatibilizer or as a binder.

The graft copolymer was prepared according to Example 1. It was blended with the materials listed in Table 9 as described in Example 1.

BMWD PP, S-EB-S-g-MA rubber, maleated polypropylene antioxidant and polyamide were described in Example 1. The ethylene-octene rubber was Engage 8150 polyolefin elastomer, containing 25% octene, commercially available from DuPont-Dow Elastomer. The polyethylene wax, polysiloxane and ceramic microspheres were described in Example 8.

The samples were prepared by mixing on an extruder, after extrusion the granulate was dried and the test specimens were extruded as described in Example 1. The results of the measurements of mechanical properties and abrasion and wear tests are given in Table 9.

• · ···« * · · • · • * • · · • * « · 9·

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•· «··· • · · • · • 4 o • · * • * -> 4 44

Example 10

This example describes the effect of using various compatibilizers based on maleated polypropylene and in different amounts, on the mechanical properties of a graft copolymer composition of PP-g-(SZMAA), BMWD PP, rubber and polyamide.

The graft copolymer was prepared as described in Example 1. It was blended with the materials listed in Table 10 as described in Example 1.

BMWD PP, polyamide, rubber and antioxidant were the same as in Example 1. Maleated PP 1 was Polypropylene Unité MP 1000 and was described in Example 1. Maleated PP 2 was Polybond 3200 polypropylene, commercially available from Uniroyal Chemicals. Maleated PP 3 was Epolene E-43 polypropylene, commercially available from Eastman Chemical Company. Maleated polypropylene 4 was Exxelor P01015 polypropylene, commercially available from Exxon Chemical Company.

The samples were prepared by mixing on an extruder, after extrusion the granulate was dried and the test specimens were extruded as described in Example 1. The results of the mechanical properties measurements are given in Table 10.

• · • ·

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• · · ·

The addition of maleated polypropylene to the composition of graft copolymer PP-g(S/MAA), BMWD PP, rubber and polyamide, provided the desired balance of mechanical properties and surface properties.

Example 11

This example describes the effect of using different amounts of glass fibers on the mechanical properties of a composition of grafted copolymer PP-g-(SZMAA) or PP-g-(S/MS/MA), BMWD PP, rubber, maleated polypropylene and polyamide.

Graft copolymer PP-g-(SZMAA) was prepared as described in Example 1. Graft copolymer PP-g-(S/MS/MA) was prepared as described in Example 2. It was mixed with the materials listed in Table 11 as described in Example 1, except for the glass fibers, which were added via a hopper.

BMWD PP, polyamide, rubber and antioxidant were the same as in Example 1. The glass fibers were type PPG-3793, coated with an aminosilane binder, commercially available from PPG Industries. The maleated polypropylene in samples 1 to 5 was Unite MP1000, commercially available from Aristech Chemical Corporation. The maleated copolymer used in sample 6 was Hercoprime HG201 polypropylene, commercially available from Montell USA Inc.

The samples were prepared by mixing on an extruder, after extrusion the granulate was dried and the test specimens were prepared as described in Example 1.

The compositions were extruded on a 40 mm Wemer-Pfleider twin-screw extruder, with interlocking, co-rotating screws, at a temperature of 250 °C, with an output of 81.45 kg/h and a screw speed of 450 rpm. Suction was used to remove by-products such as water and residual monomer. The results of the mechanical property measurements are given in Table 11.

• ·

Table 11 Sample 1 2 3 4 5 6 PP-g-(SZMAA) (wt%) 21.5 16.8 12 9.5 16.8 - PP-g-(S/MS/MA) (wt%) - - - - - 14 BMWD PP (wt%) 23.5 18.2 13 10.5 18.2 14.6 S-EB-S-g-MA (wt%) 15 15 15 20 5 15 Polyamide (wt%) 25 25 25 25 25 25 Glass fibers (wt%) 10 20 30 30 30 30 Maleated PP (wt%) 5 5 5 5 5 1.4 Antioxidant (pph) 0.2 0.2 0.2 0.2 0.2 0.2 Calcium stearate (pph) 0.1 0.1 0.1 0.1 0.1 o,i Izod Notch Strength (J/cm) 0.82 1.1 1.4 2.2 0.59 1.2 Tensile yield strength (MPa) 49.5 63.6 73.3 60.4 80.2 86.3 Bending yield strength (MPa) 62.1 74.5 84.9 68.5 89.8 108.2 Flexural modulus, (MPa) 2132 3209 4195 3202 5906 4409 Elongation at break (%) 4.1 3.6 3.4 4.5 2 4.6 Elongation at yield point (%) 4 3.5 3.4 4.2 2 4.6 HDT 455 kPa (°C) 129 138 141 123 157 150

The data show that the addition of glass fibers to graft copolymer compositions provides excellent strength, stiffness, and HDT, but also reduces the elongation at break.

Example 12

This example shows the effect of using different fillers on the mechanical properties of a grafted copolymer composition of PP-g-(S/MAA), BMWD PP, rubber and polyamide.

The graft copolymer was prepared as described in Example 1. The graft copolymer was then blended with various materials listed in Table 12 as described in Example 1.

BMWD PP, polyamide and rubber were the same as in Example 1.

The samples were prepared on a 34 mm Leistritz twin-screw extruder, with interlocking, co-rotating screws, at a temperature of 245 °C, a screw speed of 300 • · · · rpm and an output of 11.325 kgh. The injection-molded test specimens were prepared as described in Example 1. The results of the mechanical property measurements are given in Table 12.

Table 12 Sample 1 2 3 PP-g-(SZMAA) (wt%) 17 17 17 BMWD PP (wt%) 18 18 18 S-EB-S-g-MA (wt%) 15 15 15 Polyamide (wt%) 20 20 20 Wollastonite (wt%) 30 - - Talc (wt%) - 30 - Calcium Carbonate (wt%) - - 30 Izod Notch Strength (J/cm) 0.59 0.91 1.1 Tensile yield strength (MPa) 43.8 40.2 35.3 Bending yield strength (MPa) 59.4 54.2 45.2 Flexural modulus, (MPa) 2108 1980 1332 Elongation at break (%) 28 41 69 Elongation at yield point (%) 15 18 20

The data show that the addition of filler improves the strength and stiffness of the compositions.

Other features, advantages and embodiments of the invention disclosed herein will be apparent to those skilled in the art upon reading the foregoing disclosure. In this regard, specific aspects of the invention have been described in considerable detail, but variations and modifications of these embodiments may be made without departing from the spirit and scope of the invention as described and claimed.

Claims (10)

(1) A composition having a weight composition of: (a) about 1% to 98% of a graft copolymer comprising a polypropylene backbone grafted with monomers selected from the group consisting of (i) at least one vinyl aromatic compound and an unsaturated carboxylic acid; and (ii) at least one aromatic vinyl compound and an unsaturated carboxylic acid; anhydrides thereof, wherein the polymerized monomers are present in an amount of about 10 to 95 parts per 100 parts of polypropylene, and b) about 2% to 99% of at least one polyamide resin. A composition according to claim 1, wherein the polypropylene material is selected from the group consisting of: (a) from a propylene homopolymer with an isotacticity index greater than 80; b) from a copolymer of propylene and olefins selected from the group consisting of ethylene and 4 to 10 C alpha-olefin, provided that the olefin is ethylene, the maximum polymerized ethylene content is about 20% by weight, the copolymer having an isotacticity index greater than 85, (c) a terpolymer of propylene and two olefins selected from the group consisting of ethylene and an alpha-olefin of 4 to 8 C, provided that the maximum alpha-olefin content is 20% by weight, and if the ethylene is one of the olefins, then the maximum content of polymerized ethylene is 5% by weight, the terpolymer has an isotacticity index greater than 85, (d) an olefin polymer composition comprising: i) about 10 to 60 wt. a propylene homopolymer having an isotacticity index greater than 80, or a copolymer of monomers selected from the group consisting of 1) propylene and ethylene, 2) propylene, ethylene and an alpha-olefin of 4 to 8 C, and 3) propylene and an alpha-olefin of 4 to 8 C, the copolymer having a polymerized propylene content greater than 85% by weight, and an isotacticity index greater than 85; ii) about 5% to 25% by weight, ethylene-propylene copolymer or alphaolefin iii to about 30% to 70% by weight of elastomeric copolymers of monomers selected from the group consisting of 1) ethylene and propylene, 2) ethylene, and 3) ethylene and an alpha-olefin of 4 to 8 C, a copolymer optionally containing about 0.5% to 10% by weight of propylene; % of polymerized diene and containing less than 70% by weight of polymerized ethylene soluble in xylene at ambient temperature, with an intrinsic viscosity, measured in tetrahydronaphthalene at 135 ° C, of about 1.5 to 4.0 dl / g, wherein the total amount of ii) and iii), based on the total olefin polymer composition, is about 50% to 90%, the weight ratio ii) / iii is less than 0.4, and the composition prepared by polymerisation, at least two steps, and having an E-modulus in bending less than 150 MPa; and (e) a thermoplastic olefin containing: (i) about 10% to 60% of propylene homopolymers having an isotacticity index of more than 80, or a copolymer of monomers selected from the group consisting of 1) ethylene and propylene, 2) ethylene, propylene, and an alpha-olefin of 4 to 8 C; and 3) from 4 to 8 C ethylene and alpha-olefin, the copolymer having a polymerized propylene content greater than 85% by weight, and an isotactic index greater than 85, ii) about 20% to 60% amorphous copolymers of monomers selected from the group consisting of 1) from ethylene and propylene 2) from ethylene, propylene and alpha-olefin of 4 to 8 C, and 3) from ethylene and alpha-olefin of 4 to 8 C, a copolymer optionally containing about 0.5% to 10% polymerized diene, and containing less than 70% polymerized ethylene soluble in xylene at room temperature, and iii) about 3% to 40% ethylene-propylene copolymers or 4-8C alpha olefin soluble in xylene at ambient temperature, the composition having E- bending modulus greater than 150 but less than 1 200 MPa. The composition of claim 2, wherein the propylene polymer material is a propylene homopolymer. The composition of claims 1 to 3, wherein the amount of graft copolymer is about 50% to 90%. Composition according to claims 1 to 4, characterized in that the polymerized monomers are styrene and methacrylic acid and the molar ratio of styrene to methacrylic acid is 60/40. The composition of claims 1 to 5, wherein the polyamide is polycaprolactam. Composition according to claims 1 to 6, characterized in that it additionally comprises a wheel 2% to 30%, based on the total weight of the composition, of at least one rubber component selected from the group consisting of: a) an olefin copolymer rubber, b) an aromatic monoalkenyl hydrocarbon-conjugated diene block copolymer, and c) of encapsulated rubber. Composition according to claims 1 to 7, characterized in that it additionally contains about 5% to 90%, based on the total weight of the composition, of a propylene polymer material with a broad molecular weight distribution. Composition according to claims 1 to 8, characterized in that it additionally contains additives for improving the abrasion and wear resistance of a composition selected from the group comprising a) about 0.5% to 10% of at least one low molecular weight polymer of ethylene or derivatives thereof having functional groups having a number average molecular weight of about 300 to 5000; and b) a combination of about 0.5% to 10% of at least one of the low molecular weight ethylene polymers in a) and about 0.5% to 10% of inorganic microspheres based on total weight; optionally polysiloxane. Products made of the compositions of claims 1 to 9.