Title of Invention	"MOULDING COMPOSITIONS"
Abstract	Moulding compositions comprising A) from 99 to 10 parts by weight of at least one semicrystalline thermoplastic polyamide and B) from 1 to 20 parts by weight of at least one copolymer composed of at least one olefin with at least one methacrylic ester or acrylic ester of an aliphatic alcohol having from 1 to 4 carbon atoms, the MFI of the copolymer B) is from 80 to 900 g/min, characterized in that the MFI has always been measured or determined at 190°C and with a test load of 2.16 kg, the polyamide has been prepared by polycondensation or hydrolytic polymerization and the alkyl group of the methacrylic ester or acrylic ester is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, iso-butyl, tert-butyl.

Title of Invention

"MOULDING COMPOSITIONS"

Abstract

Moulding compositions comprising A) from 99 to 10 parts by weight of at least one semicrystalline thermoplastic polyamide and B) from 1 to 20 parts by weight of at least one copolymer composed of at least one olefin with at least one methacrylic ester or acrylic ester of an aliphatic alcohol having from 1 to 4 carbon atoms, the MFI of the copolymer B) is from 80 to 900 g/min, characterized in that the MFI has always been measured or determined at 190°C and with a test load of 2.16 kg, the polyamide has been prepared by polycondensation or hydrolytic polymerization and the alkyl group of the methacrylic ester or acrylic ester is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, iso-butyl, tert-butyl.

Full Text	Polvamide moulding compositions with improved flowabilitv This invention relates to moulding compositions based on at least one semicrystalline thermoplastic polyamide and on at least one copolymer composed of at least one olefin, preferably of one a-olefin, with at least one methacrylic ester or acrylic ester of an aliphatic alcohol having from 1 to 4 carbon atoms, the MFI (melt flow index) of the copolymer being not less than 50 g/10 min, and to a process for preparation of these moulding compositions, and also to the use of these moulding compositions for production of mouldings or of semifinished products via injection moulding or extrusion. Highly flowable thermoplastic compositions are of interest for a wide variety of injection moulding applications. By way of example, thin-walled components in the electrical, electronics and motor vehicle industry require low viscosities from the thermoplastics composition in order to permit material to be charged to the mould with minimum injection pressures and, respectively, clamping forces in the appropriate injection moulding machines. This also applies to simultaneous charging of material to two or more injection moulding components by way of a shared runner system in what are known as multicavity tooling systems. Shorter cycle times can moreover often be achieved using low-viscosity thermoplastic compositions. Good flowabilities are also specifically very important for highly filled thermoplastic compositions, e.g. with glass fibre and/or mineral contents above 40% by weight. However, although the thermoplastic compositions have high flowability, the actual components produced therefrom are subjected to stringent mechanical requirements, and the lowering of viscosity cannot therefore be permitted to cause significant impairment of mechanical properties. There are a number of ways of obtaining highly flowable, low-viscosity thermoplastic moulding compositions. One way uses low-viscosity polymer resins with very low molecular weight as base polymers for the thermoplastic moulding compositions. However, the use of low-molecular-weight polymer resins is often associated with sacrifices in mechanical properties, in particular toughness. Preparation of a low-viscosity polymer resin in an existing polymerization plant moreover often requires complicated intervention attended by capital expenditure. Another way uses what are known as flow aids, also termed flow agents or flow assistants or internal lubricants, which can be added as an additive to the polymer resin. These flow aids are known from the literature, e.g. in Kunststoffe 2000, 9, p. 116-118, and by way of example can be fatty acid esters of polyols, or amides derived from fatty acids and from amines. However, these fatty acid esters, such as pentaerythritol tetrastearate or ethylene glycol dimontanoate, have only limited miscibility with polar thermoplastics, such as polyamides, polyalkylene terephthalates or polycarbonates. Their concentration increases at the surface of the moulding and they are therefore also used as mould-release aids. However, on heat-ageing or else, in the case of polyamides, on absorption of moisture, particularly if concentrations are relatively high, the flow aids can migrate out of these mouldings to the surface and become concentrated there. By way of example, in coated mouldings this can lead to problems with regard to adhesion to paint or to metal. As an alternative to the surface-active flow aids, it is possible to use internal flow aids which are compatible with the polymer resins. Examples of those suitable for this purpose are low-molecularweight compounds or branched, highly branched or dendritic polymers whose polarity is similar to that of the polymer resin. These highly branched or dendritic systems are known from the literature and their basis can by way of example be branched polyesters, polyamides, polyesteramides, polyethers or polyamines, as described in Kunststoffe 2001, 91, pp. 179-190, or in Advances in Polymer Science 1999, 143 (Branched Polymers II), pp. 1-34. EP-A 0 682 057 describes the use of the nitrogen-containing first-generation 4-cascade dendrimer: l,4-diaminobutane[4]propylamine (N,N'-tetrabis(3-aminopropyl)-l,4-butanediamine) DAB(PA)4 to lower viscosity in nylon-6, nylon-6,6 and polybutylene terephthalate (PBT). While use of DAB(PA)4 to lower viscosity in polyamides has practically no effect on the impact resistance of the resultant moulding compositions (difference PBT. WO-A 95/06081 (= US 5 493 000) describes the use of three-dimensional branched polymers having rigid aromatic units in blends with polyamide in order to increase the stiffness of the material and the ultimate tensile strength, with simultaneous reduction in viscosity and in the tensile strain at break of the blends. EP-A 0 994 157 (= AU 6 233 499 A) describes the use of highly branched polymers which are based on aromatics and which are added during caprolactam polycondensation and are therefore copolymerized. Compositions composed of polyamides in which highly branched polymers have been copolymerized exhibit better mechanical properties and better flowabilities here than comparative compositions without the highly branched components. Addition of the highly branched polymers during the polymerization reaction is described, but no addition to a polymer melt is described. In principle, improvements in the flowability of polyamides can also be achieved via addition of phenols, of bisphenols, and of similar low-molecular-weight additives. EP-A 0 240 887 (= US 5 212 224) describes moulding compositions composed of polyamide, of a rubber and of a bisphenol, these exhibiting improved flowability brought about via the additive. DE-A 32 48 329 (= US 4 628 069) describes addition of phenolic compounds to polyamide in order to reduce water absorption. Alongside improvement in flowability, it is often desirable to improve the toughness of the materials. For this, other copolymers which are based on ethene and on acrylic or methacrylic esters and which bring about an improvement in toughness can also be added to the thermoplastics used. DE-A 2 758 568 (= US 4 362 846) and DE-A 2 801 585 (= US 4 362 846) describe modification of the toughness of polyamides with acrylate-grafted polyolefins. It is emphasized that the use of the acrylate-modified polyolefins leads to an increase in melt viscosity. EP-A 1 191 067 (= US 6 759 480) describes modification of the toughness of thermoplastics, inter alia of polyamide and polybutylene terephthalate, via a mixture composed of a copolymer composed of ethene with an unreactive alkyl acrylate, and also of a copolymer composed of ethene with an acrylate having an additional reactive group. There is no discussion of the flowability of the moulding compositions. The object of the present invention then consisted in lowering the viscosity of polyamide polycondensate compositions by treating the polymer melt with additives, without any resultant need to accept the losses that occur when using low-viscosity linear polymer resins or when using additives disclosed in the literature in properties such as impact resistance and hydrolysis resistance. In terms of stiffness and ultimate tensile strength, the polyamide compositions should if at all possible not differ significantly from the polyamide polycondensate compositions not treated with additives, in order to permit problem-free replacement of the materials for plastic structures based on polyamide. Achievement of the object and thus the subject matter of the invention is provided by polyamide moulding compositions comprising A) from 99 to 10 parts by weight, preferably from 98 to 30 parts by weight, particularly preferably from 97 to 60 parts by weight, of at least one semicrystalline thermoplastic polyamide and B) from 1 to 20 parts by weight, preferably from 2 to 15 parts by weight, particularly preferably from 3 to 9 parts by weight, of at least one copolymer composed of at least one olefin, preferably of one a-olefin, with at least one methacrylic ester or acrylic ester of an aliphatic alcohol having from 1 to 4 carbon atoms, the MFI of the copolymer B) being not less than 50 g/10 min, and preferably being from 80 to 900 g/10 min. For the purposes of the present invention, MFI (melt flow index) has always been measured or determined at 190°C and with a test load of 2.16 kg. Surprisingly, it has been found that mixtures composed of at least one semicrystalline thermoplastic polyamide with copolymers of olefins with methacrylic esters or with acrylic esters of aliphatic alcohols having from 1 to 4 carbon atoms, their MFI being not less than 50 g/10 min, lead to the desired lowering of the melt viscosity of the inventive moulding compositions prepared therefrom. In comparison with moulding compositions without copolymer B), the inventive moulding compositions exhibit no significant losses, and indeed instead in some cases improvements, in properties such as low-temperature impact resistance, hydrolysis resistance, density, surface quality. The moulding compositions have excellent suitability for use in thin-wall technology. According to the invention, the compositions comprise, as component A), at least one semicrystalline thermoplastic polyamide. The polyamides to be used according to the invention can be prepared by various processes and can be synthesized from very different units, and, in each specific application, can be used alone or can be treated with processing aids, with stabilizers, with polymeric alloy partners (e.g. elastomers) or else with reinforcing materials (e.g. mineral fillers or glass fibres) to give materials with specifically adjusted combinations of properties. Blends with contents of other polymers, e.g. of polyethylene, polypropylene, ABS (acrylonitrile-butadiene-styrene copolymer) are also suitable, and, if appropriate, one or more compatibilizers can be used. The properties of the polyamides can be improved via addition of elastomers, e.g. with regard to the impact resistance of, for example, reinforced polyamides. The wide variety of possible combinations gives access to a very large number of products with very different properties. A wide variety of procedures has been disclosed for preparation of polyamides using, as a function of the desired final product, different monomer units, a variety of chain regulators in order to set the desired molecular weight, or else monomers having reactive groups for intended subsequent posttreatments. The industrially relevant processes for preparation of polyamides mostly proceed by way of polycondensation in the melt. Hydrolytic polymerization of lactams is also polycondensation for this purpose. According to the invention, polyamides preferably to be used as component A) are semicrystalline polyamides which can be prepared starting from diamines and from dicarboxylic acids and/or from lactams having fewer than 5 ring members or from corresponding amino acids. Starting materials which can be used are aliphatic and/or aromatic dicarboxylic acids such as adipic acid, 2,2,4- and 2,4,4-trimethyladipic acid, azelaic acid, sebacic acid, isophthalic acid, terephthalic acid, aliphatic and/or aromatic diamines, e.g. tetramethylenediamine, hexamethylenediamine, 1,9- nonanediamine, 2,2,4- and 2,4,4-trimethylhexamethylenediamine, the isomeric diaminodicyclohexylmethanes, diaminodicyclohexylpropanes, bisaminomethylcyclohexane, phenylenediamines, xylylenediamines, aminocarboxylic acids, e.g. aminocaproic acid, and, respectively the corresponding lactams. Copolyamides composed of two or more of the monomers mentioned are included. According to the invention, it is particularly preferable to use caprolactams, and very particularly preferable to use s-caprolactam, or else most of the compounded materials based on PA6, on PA66 and on other aliphatic and/or aromatic polyamides and, respectively, copolyamides, where there are from 3 to 11 methylene groups in these materials for each polyamide group in the polymer chain. The semicrystalline polyamides to be used according to the invention as component A) can also be used in a mixture with other polyamides and/or with other polymers. Conventional additives, e.g. mould-release agents, stabilizers and/or flow aids can be admixed with the polyamides in the melt or can be applied to their surface. The inventive compositions comprise, as component B), copolymers, preferably random copolymers, composed of at least one olefin, preferably an a-olefin, and of at least one methacrylic ester or acrylic ester of an aliphatic alcohol having from 1 to 4 carbon atoms, the MFI of the copolymer B) being not less than 50 g/10 min, and preferably being from 80 to 900 g/10 min. In one preferred embodiment, less than 4% by weight, particularly preferably less than 1.5% by weight and very particularly preferably 0% by weight of the copolymer B) is composed of monomer units which contain further reactive functional groups (selected from the group consisting of epoxides, oxetanes, anhydrides, imides, aziridines, furans, acids, amines, oxazolines). Suitable olefins, preferably a-olefins as constituent of the copolymers B) preferably have from 2 to 10 carbon atoms and can be unsubstituted or have substitution by one or more aliphatic, cycloaliphatic or aromatic groups. Preferred olefins have been selected from the group consisting of ethene, propene, 1-butene, 1-pentene, 1-hexene, 1-octene. 3-methyl-l-pentene. Particularly preferred olefins are ethene and propene, and ethene is very particularly preferred. Mixtures of the olefins described are also suitable. In another preferred embodiment, the further reactive functional groups (selected from the group consisting of epoxides, oxetanes, anhydrides, imides, aziridines, furans, acids, amines, oxazolines) of the copolymer B) are introduced exclusively by way of the olefins into the copolymer B). The content of the olefin in the copolymer B) is from 50 to 95% by weight, preferably from 61 to 93% by weight. The copolymer B) is further defined via the second constituent alongside the olefin. A suitable second constituent is alkyl esters of acrylic acid or methacrylic acid whose alkyl group is formed by from 1 to 4 carbon atoms. By way of example, the alkyl group of the methacrylic or acrylic ester can have been selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl. The alkyl group of the methacrylic or acrylic ester is preferably selected from the group consisting of ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl. Very particularly preferably, the alkyl group of the methacrylic or acrylic ester has 4 carbon atoms and comprises the n-butyl, secbutyl, isobutyl or tert-butyl group. Particular preference is given to n-butyl acrylate. According to the invention, particular preference is given to copolymers B) in which the olefin is copolymerized with butyl acrylate, in particular n-butyl acrylate. Mixtures of the acrylic or methacrylic esters described are also suitable. It is preferable here to use more than 50% by weight, particularly preferably more than 90% by weight and very particularly preferably 100% by weight, of butyl acrylate, based on the total amount of acrylic and methacrylic ester in copolymer B). In another preferred embodiment, the further reactive functional groups (selected from the group consisting of epoxides, oxetanes, anhydrides, imides, aziridines, furans, acids, amines, oxazolines) of the copolymer B) are introduced exclusively by way of acrylic or methacrylic esters into the copolymer B). The content of the acrylic or methacrylic esters in the copolymer B) is preferably from 5 to 50% by weight, particularly preferably from 7 to 39% by weight. A feature of suitable copolymers B) is not only their constitution but also their low molecular weight. Accordingly, copolymers B) suitable for the inventive moulding compositions are only those whose MFI value, measured at 190°C and with a load of 2.16 kg, is at least 50 g/10 min, preferably from 80to900g/10min. Examples of suitable copolymers as component B) can have been selected from the group of the materials supplied by Arkema (formerly Atofina) with the trade mark Lotryl®, which are usually used as hot-melt adhesive. In one preferred embodiment, the inventive polyamide moulding compositions can comprise, in addition to components A) and B), one or more of the components of the series C), D), E), F) and G). In one preferred embodiment of this type, the thermoplastic polyamide moulding compositions can therefore also, if appropriate, comprise, in addition to components A) and B), C) from 0.001 to 70 parts by weight, preferably from 5 to 50 parts by weight, particularly preferably from 9 to 47 parts by weight, of at least one filler or reinforcing material. However, the filler or reinforcing material used can also comprise mixtures composed of two or more different fillers and/or reinforcing materials, for example based on talc, mica, silicate, quartz, titanium dioxide, wollastonite, kaolin, amorphous silicas, magnesium carbonate, chalk, feldspar, barium sulfate, glass beads and/or fibrous fillers and/or reinforcing materials based on carbon fibres and/or glass fibres. It is preferable to use mineral particulate fillers based on talc, mica, silicate, quartz, titanium dioxide, wollastonite, kaolin, amorphous silicas, magnesium carbonate, chalk, feldspar, barium sulfate and/or glass fibres. It is particularly preferable to use mineral particulate fillers based on talc, wollastonite, kaolin and/or glass fibres. Particularly for applications which demand isotropy in dimensional stability and demand high thermal dimensional stability, for example in motor vehicle applications for exterior bodywork parts, it is preferable to use mineral fillers, in particular talc, wollastonite or kaolin. A further particular preference is also the use of acicular mineral fillers, according to the invention, acicular mineral fillers are a mineral filler with highly pronounced acicular character. An example which may be mentioned is acicular wollastonites. The lengtkdiameter ratio of the material is preferably from 2:1 to 35:1, particularly preferably from 3:1 to 19:1, most preferably from 4:1 to 12:1. The average particle size of the inventive acicular minerals is preferably smaller than 20 urn, particularly preferably smaller than 15 (im, with particular preference smaller than 10 um, determined using a CILAS GRANULOMETER. As previously described above, the filler and/or reinforcing material may, if appropriate, have been surface-modified, for example using a coupling agent or coupling agent system, e.g. based on silane. However, the pretreatment is not absolutely essential. In particular when glass fibres are used, polymer dispersions, film-formers, branching agents and/or glass fibre processing aids can also be used in addition to silanes. The glass fibres to be used with particular preference according to the invention whose fibre diameter is generally from 7 to 18 um, preferably from 9 to 15 um, are added in the form of continuous-filament fibres or in the form of chopped or ground glass fibres. The fibres can have been equipped with a suitable size system and with a coupling agent or coupling agent system, e.g. based on silane. Familiar coupling agents based on silane for pretreatment are silane compounds having by way of example the general formula (I) (I) (X-(CH2)q)k-Si-(0-CrH2r+1)4.k where the substituents are as follows: X: NH2-,HO-or H2c^-^c—, H q: a whole number from 2 to 10, preferably from 3 to 4, r: a whole number from 1 to 5, preferably from 1 to 2, and k: a whole number from 1 to 3, preferably 1. Preferred coupling agents are silane compounds from the group of aminopropyltrimethoxysilane, aminobutyltrimethoxysilane, aminopropyltriethoxysilane, aminobutyltriethoxysilane, and also the corresponding silanes which contain a glycidyl group as substituent X. The amounts generally used of the silane compounds for equipping the fillers are from 0.05 to 2% by weight, preferably from 0.25 to 1.5% by weight and in particular from 0.5 to 1% by weight, based on the mineral filler used for surface coating. The consequence of processing to give the moulding composition or moulding is that the d97 or d50 value of the particulate fillers in the moulding composition or in the moulding can be smaller than that of the fillers initially used. A consequence of the processing to give the moulding composition or moulding is that the length distributions of the glass fibres in the moulding composition or in the moulding can be shorter than those of the material initially used. In one alternative preferred embodiment, the polyamide moulding compositions can also, if appropriate, comprise, in addition to components A) and B), and/or C), D) from 0.001 to 65 parts by weight of at least one flame retardant additive. Flame retardants that can be used in component D) are commercially available organic halogen compounds with synergists or are commercially available organic nitrogen compounds or are organic/inorganic phosphorus compounds individually or in a mixture. It is also possible to use mineral flame retardant additives such as magnesium hydroxide or Ca Mg carbonate hydrates (e.g. DE-A 4 236 122 (= CA 210 9024 Al)). It is also possible to use salts of aliphatic or of aromatic sulphonic acids. Examples which may be mentioned of halogen-containing, in particular brominated and chlorinated compounds are: ethylene-l,2-bistetrabromophthalimide, epoxidized tetrabromobisphenol A resin, tetrabromobisphenol A oligocarbonate, tetrachlorobisphenol A oligocarbonate, pentabromopolyacrylate, brominated polystyrene and decabromodiphenyl ether. Examples of suitable organophosphorus compounds are the phosphorus compounds according to WO-A 98/17720 (= US 6 538 024), e.g. triphenyl phosphate (TPP), resorcinol bis(diphenyl phosphate) (RDP) and the oligomers derived therefrom, and also bisphenol A bis(diphenyl phosphate) (BDP) and the oligomers derived therefrom, and organic and inorganic phosphonic acid derivatives and salts thereof, organic and inorganic phosphinic acid derivatives and salts thereof, in particular metal dialkylphosphinates, e.g. aluminium tris[dialkylphosphinates] or zinc bisfdialkylphosphinates] and moreover red phosphorus, phosphites, hypophosphites, phospine oxides, phosphazenes, melamine pyrophosphate and mixtures of these. Nitrogen compounds which can be used are those from the group of the allantoin derivatives, cyanuric acid derivatives, dicyandiamide derivatives, glycoluril derivatives, guanidine derivatives, ammonium derivatives and melamine derivatives, preferably allantoin, benzoguanamine, glycoluril, melamine, condensates of melamine, e.g. melem, melam or melom and, respectively, higher-condensation-level compounds of this type and adducts of melamine with acids, e.g. with cyanuric acid (melamine cyanurate), phosphoric acid (melamine phosphate) or with condensed phosphoric acids (e.g. melamine polyphosphate). Examples of suitable synergists are antimony compounds, in particular antimony trioxide, sodium antimonate and antimony pentoxide, zinc compounds, e.g. zinc borate, zinc oxide, zinc phosphate and zinc sulphide, tin compounds, e.g. tin stannate and tin borate, and also magnesium compounds, e.g. magnesium oxide, magnesium carbonate and magnesium borate. The materials known as carbonizers can also be added to the flame retardant, examples being phenolformaldehyde resins, polycarbonates, polyphenyl ethers, polyimides, polysulphones, polyether sulphones, polyphenylene sulphides and polyether ketones, and also antidrip agents, such as tetrafluoroethylene polymers. In a further alternative preferred embodiment, the polyamide moulding compositions can also, if appropriate, comprise, in addition to components A) and B), and/or C) and/or D), E) from 0.001 to 80 parts by weight, particularly preferably from 2 to 25 parts by weight, of at least one elastomer modifier. The elastomer modifiers to be used as component E) encompass one or more graft polymers of E.I from 5 to 95% by weight, preferably from 30 to 90% by weight, of at least one vinyl monomer, E.2 from 95 to 5% by weight, preferably from 70 to 10% by weight, of one or more graft bases with glass transition temperatures The median particle size (dso value) of the graft base E.2 is generally from 0.05 to 10 jam, preferably from 0.1 to 5 um, particularly preferably from 0.2 to 1 um. Monomers E. 1 are preferably mixtures composed of E. 1.1 from 50 to 99% by weight of vinylaromatics and/or ring-substituted vinylaromatics (such as styrene, a-methyl styrene, p-methyl styrene, p-chlorostyrene) and/or (Ci-Cs)-alkyl methacrylates (e.g. methyl methacrylate, ethyl methacrylate) and E.I.2 from 1 to 50% by weight of vinyl cyanides (unsaturated nitriles, such as acrylonitrile and methacrylonitrile) and/or (d-C8)-alkyl (meth)acrylates (e.g. methyl methacrylate, n-butyl acrylate, tert-butyl acrylate) and/or derivatives (such as anhydrides and imides) of unsaturated carboxylic acids (e.g. maleic anhydride and N-phenylmaleimide). Preferred monomers E.I.I have been selected from at least one of the monomers styrene, ot-methylstyrene and methyl methacrylate, and preferred monomers E.I.2 have been selected from at least one of the monomers acrylonitrile, maleic anhydride and methyl methacrylate. Particularly preferred monomers are E. 1.1 styrene and E. 1.2 acrylonitrile. Examples of suitable graft bases E.2 for the graft polymers to be used in the elastomer modifiers E) are diene rubbers, EP(D)M rubbers, i.e. rubbers based on ethylene/propylene and, if appropriate, diene, acrylate rubbers, polyurethane rubbers, silicone rubbers, chloroprene rubbers and ethylenevinyl acetate rubbers. Preferred graft bases E.2 are diene rubbers (e.g. based on butadiene, isoprene, etc.) or mixtures of diene rubbers, or are copolymers of diene rubbers or of their mixtures with further copolymerizable monomers (e.g. according to E. 1.1 and E. 1.2), with the proviso that the glass transition temperature of component E.2 is Examples of particularly preferred graft bases E.2 are ABS polymers (emulsion, bulk and suspension ABS), as described by way of example in DE-A 2 035 390 (= US-A 3 644 574) or in DE-A 2 248 242 (= GB-A 1 409 275) or in Ullmann, Enzyklopadie der Technischen Chemie [Encyclopaedia of Industrial Chemistry], Vol. 19 (1980), pp. 280 et seq. The gel content of the graft base E.2 is preferably at least 30% by weight, particularly preferably at least 40% by weight (measured in toluene). The elastomer modifiers or graft polymers E) are prepared via free-radical polymerization, e.g. via emulsion, suspension, solution or bulk polymerization, preferably via emulsion or bulk polymerization. Other particularly suitable graft rubbers are ABS polymers which are prepared via redox initiation using an initiator system composed of organic hydroperoxide and ascorbic acid according to US-A 4937285. Because it is known that the graft monomers are not necessarily entirely grafted onto the graft base during the grafting reaction, products which are obtained via (co)polymerization of the graft monomers in the presence of the graft base and are produced concomitantly during the work-up are also graft polymers B according to the invention. Suitable acrylate rubbers are based on graft bases E.2 which are preferably polymers composed of alkyl acrylates, if appropriate with up to 40% by weight, based on E.2, of other polymerizable, ethylenically unsaturated monomers. Among the preferred polymerizable acrylic esters are Ci-C8- alkyl esters, such as methyl, ethyl, butyl, n-octyl and 2-ethylhexyl esters; haloalkyl esters, preferably halo-Ci-Cg-alkyl esters, such as chloroethyl acrylate, and also mixtures of these monomers. For crosslinking, monomers having more than one polymerizable double bond can be copolymerized. Preferred examples of crosslinking monomers are esters of unsaturated monocarboxylic acids having from 3 to 8 carbon atoms and of unsaturated monohydric alcohols having from 3 to 12 carbon atoms, or of saturated polyols having from 2 to 4 OH groups and from 2 to 20 carbon atoms, e.g. ethylene glycol dimethacrylate, allyl methacrylate; polyunsaturated heterocyclic compounds, e.g. trivinyl and triallyl cyanurate; polyfunctional vinyl compounds, such as di- and trivinylbenzenes; and also triallyl phosphate and diallyl phthalate. Preferred crosslinking monomers are allyl methacrylate, ethylene glycol dimethacrylate, diallyl phthalate and heterocyclic compounds which have at least 3 ethylenically unsaturated groups. Particularly preferred crosslinking monomers are the cyclic monomers triallyl cyanurate, triallyl isocyanurate, triacryloylhexahydro-s-triazine, triallylbenzenes. The amount of the crosslinking monomers is preferably from 0.02 to 5% by weight, in particular from 0.05 to 2% by weight, based on the graft base E.2. In the case of cyclic crosslinking monomers having at least 3 ethylenically unsaturated groups, it is advantageous to restrict the amount to below 1% by weight of the graft base E.2. Examples of preferred "other" polymerizable, ethylenically unsaturated monomers which can serve alongside the acrylic esters, if appropriate, for preparation of the graft base E.2 are acrylonitrile, styrene, a-methylstyrene, acrylamides, vinyl d-C6-alkyl ethers, methyl methacrylate, butadiene. Acrylate rubbers preferred as graft base E.2 are emulsion polymers whose gel content is at least 60% by weight. Further suitable graft bases according to E.2 are silicone rubbers having sites active for grafting purposes, as described in DE-A 3 704 657 (= US 4 859 740), DE-A 3 704 655 (= US 4 861 831), DE-A 3 631 540 (= US 4 806 593) and DE-A 3 631 539 (= US 4 812 515). Alongside elastomer modifiers based on graft polymers, it is also possible to use, as component E), elastomer modifiers not based on graft polymers but having glass transition temperatures preferably lastomers with block copolymer structure. Among these can also be, by way of example, elastomers which can undergo thermoplastic melting. Preferred materials mentioned here by way of example are EPM rubbers, EPDM rubbers and/or SEES rubbers. In a further alternative preferred embodiment, the polyamide moulding compositions can also, if appropriate, comprise, in addition to components A) and B), and/or C) and/or D) and/or E), F) from 0.001 to 10 parts by weight, preferably from 0.05 to 3 parts by weight, of other conventional additives. For the purposes of the present invention, examples of conventional additives are stabilizers (e.g. UV stabilizers, heat stabilizers, gamma-ray stabilizers), antistatic agents, flow aids, mould-release agents, further fire-protection additives, emulsifiers, nucleating agents, plasticizers, lubricants, dyes, pigments and additives for increasing electrical conductivity. The additives mentioned and further suitable additives are described by way of example in Gachter, Miiller, Kunststoff-Additive [Plastics Additives], 3rd Edition, Hanser-Verlag, Munich, Vienna, 1989 and in Plastics Additives Handbook, 5th Edition, Hanser-Verlag, Munich, 2001. The additives may be used alone or in a mixture, or in the form of masterbatches. Examples of stabilizers which can be used are sterically hindered phenols, hydroquinones, aromatic secondary amines, e.g. diphenylamines, substituted resorcinols, salicylates, benzotriazoles and benzophenones, and also various substituted representatives of these groups and mixtures thereof. Examples of pigments and dyes which can be used are titanium dioxide, zinc sulphide, ultramarine blue, iron oxide, carbon black, phthalocyanines, quinacridones, perylenes, nigrosin and anthraquinones. Examples of nucleating agents which can be used are sodium phenylphosphinate or calcium phenylphosphinate, aluminium oxide, silicon dioxide, and also preferably talc. Examples of lubricants and mould-release agents which can be used are ester waxes, pentaerythritol tetrastearate (PETS), long-chain fatty acids (e.g. stearic acid or behenic acid) and esters, salts thereof (e.g. Ca stearate or Zn stearate), and also amide derivatives (e.g. ethylenebisstearylamide) or montan waxes (mixtures composed of straight-chain, saturated carboxylic acids having chain lengths of from 28 to 32 carbon atoms), and also low-molecular-weight polyethylene waxes and polypropylene waxes. Examples of plasticizers which can be used are dioctyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, hydrocarbon oils, N-(n-butyl)benzenesulphonamide. Additives which can be added to increase electrical conductivity are carbon blacks, conductivity blacks, carbon fibrils, nanoscale graphite fibres and nanoscale carbon fibres, graphite, conductive polymers, metal fibres, and also other conventional additives for increasing electrical conductivity. Nanoscale fibres which can preferably be used are those known as "single-wall carbon nanorubes" or "multiwall carbon nanotubes" (e.g. from Hyperion Catalysis). In a further alternative preferred embodiment, the polyamide moulding compositions can also, if appropriate, comprise, in addition to components A) and B), and/or C), and/or D), and/or E), and/or F), G) from 0.5 to 30 parts by weight, preferably from 1 to 20 parts by weight, particularly preferably from 2 to 10 parts by weight, and most preferably from 3 to 7 parts by weight, of compatibilizer. Compatibilizers used preferably comprise thermoplastic polymers having polar groups. According to the invention, polymers used are therefore those which contain G. 1 a vinylaromatic monomer, G.2 at least one monomer selected from the group of C2-Ci2-alkyl methacrylates, C2-Ci2- alkyl acrylates, methacrylonitriles and acrylonitriles and G.3 dicarboxylic anhydrides containing a,p-unsaturated components. The component G used preferably comprises terpolymers of the monomers mentioned. Accordingly, it is preferable to use terpolymers of styrene, acrylonitrile and maleic anhydride. In particular, these terpolymers contribute to improvement in mechanical properties, such as tensile strength and tensile strain at break. The amount of maleic anhydride in the terpolymer can vary widely. The amount is preferably from 0.2 to 5 mol%. Amounts of from 0.5 to 1.5 mol% are particularly preferred. In this range, particularly good mechanical properties are achieved in relation to tensile strength and tensile strain at break. The terpolymer can be prepared in a known manner. One suitable method is to dissolve monomer components of the terpolymer, e.g. styrene, maleic anhydride or acrylonitrile, in a suitable solvent, e.g. methyl ethyl ketone (MEK). One or, if appropriate, more chemical initiators are added to this solution. Examples of suitable initiators are peroxides. The mixture is then polymerized at elevated temperatures for a number of hours. The solvent and the unreacted monomers are then removed in a manner known per se. The ratio of component G.I (vinylaromatic monomer) to component G.2, e.g. the acrylonitrile monomer in the terpolymer is preferably from 80:20 to 50:50. Styrene is particularly preferred as vinylaromatic monomer G. 1. Acrylonitrile is particularly preferably suitable for component G.2. Maleic anhydride is particularly preferably suitable as component G.3. EP-A 0 785 234 (= US 5 756 576) and EP-A 0 202 214 (= US 4 713 415) describe examples of compatibilizers G) which can be used according to the invention. According to the invention, particular preference is given to the polymers mentioned in EP-A 0 785 234. The compatibilizers can be present in component G) alone or in any desired mixture with one another. Another substance particularly preferred as compatibilizer is a terpolymer of styrene and acyrlonitrile in a ratio of 2.1:1 by weight containing 1 mol% of maleic anhydride. Component G) is used particularly when the moulding composition comprises graft polymers, as described under E). According to the invention, the following combinations of the components are preferred: A,B;A,B,C; A,B,D; A,B,E; A,B,F; A,B,G; A,B,C,D; A,B,C,E; A,B,C,F; A,B,C,G; A,B,D,E; A,B,D,F; A,B,D,G; A,B,E,F; A,B,E,G; A,B,F,G; A,B,C,D,E; A,B,C,D,F; A,B,C,D,G; A,B,C,E,F; A,B,C,E,G; A,B,C,F,G; A,B,E,F,G; A,B,D,E,F; A,B,D,E,G; A,B,D,F,G; A,B,C,D,E,F; A,B,C,D,E,G; A,B,C,D,F,G; A,B,D,E,F,G; A,B,C,E,F,G; A,B,C,D,E,F,G. The present invention further provides the preparation of the inventive polyamide moulding compositions. This takes place by known processes via mixing of the components in the appropriate proportions by weight. The mixing of the components preferably takes place at temperatures of from 220 to 330°C by combining, mixing, kneading, extruding or rolling the components together. It can be advantageous to premix individual components. It can moreover be advantageous to produce mouldings or semifinished products directly from a physical mixture (dry blend) which has been prepared at room temperature (preferably from 0 to 40°C) and which is composed of premixed and/or individual components. The invention further provides the mouldings or semifinished products to be produced from the inventive polyamide moulding compositions comprising A) from 99 to 10 parts by weight, preferably from 98 to 30 parts by weight, particularly preferably from 97 to 60 parts by weight, of at least one semicrystalline thermoplastic polyamide and B) from 1 to 20 parts by weight, preferably from 2 to 15 parts by weight, particularly preferably from 3 to 9 parts by weight, of at least one copolymer composed of at least one olefin, preferably of one a-olefin, with at least one methacrylic ester or acrylic ester of an aliphatic alcohol having from 1 to 4 carbon atoms, the MFI being not less than 50 g/10 min and preferably being from 80 to 900 g/10 min. Further advantages surprisingly exhibited by the inventive moulding compositions in comparison with the prior art are the following: markedly improved flowability, in particular at shear rates relevant for thermoplastics processing; markedly reduced injection pressure in processing via injection moulding; improved low temperature impact resistance; lower density; improved hydrolysis resistance; improved surface quality of the mouldings. The inventive polyamide moulding compositions can be processed by conventional processes, for example via injection moulding or extrusion, to give mouldings or semifinished products. Examples of semifinished products are foils and sheets. Particular preference is given to processing via injection moulding. The mouldings or semifinished products to be produced according to the invention from the polyamide moulding compositions can be small or large parts and, by way of example, can be used in the motor vehicle, electrical, electronics, telecommunications, information technology, or computer industry, in the household, in sports, in medicine or in the entertainment industry. In particular, the inventive polyamide moulding compositions can be used for applications which require high melt flowability. An example of these applications is what is known as thin-wall technology, in which the wall thicknesses of mouldings to be produced from the moulding compositions are less than 2.5 mm, preferably less than 2.0 mm, particularly preferably less than 1.5 mm and most preferably less than 1.0mm. Another example of these applications is cycle time reduction, e.g. via reduction of processing temperature. Another application example is the processing of the moulding compositions by way of what are known as multitooling systems, in which material is charged by way of a runner system to at least 4 moulds, preferably at least 8 moulds, particularly preferably at least 12 moulds, most preferably at least 16 moulds, in an injection moulding procedure. Mouldings composed of the inventive moulding compositions can also be used for parts of the cooling circulation system and/or of the oil circulation system of motor vehicles. Examples: The following were used: Nylon-6: Durethan® B29, commercially available product from Lanxess Deutschland GmbH, Leverkusen, Germany, with relative solution viscosity 2.9 (measured in m-cresol at 25°C) Glassfibre: Glassfibre sized with silane-containing compounds and with diameter 11 um (CS 7928, commercially available product from Lanxess N.V., Antwerp, Belgium) Lotryl® 28 BA 175: Copolymer composed of ethene and n-butyl acrylate with ethene content of 70- 74% by weight and MFI of 175 (commercially available product from Atofina Deutschland, Dusseldorf; since October 2004 Arkema GmbH, Dusseldorf) The compositions based on PA6 were compounded in a ZSK32 (Werner and Pfleiderer) twin-screw extruder at melt temperatures of from 270 to 285°C to give moulding compositions, and the melt was discharged into a water bath and then pelletized. The test specimens for the tests listed in the table were injection-moulded in an Arburg 320-210-500 injection-moulding machine at a melt temperature of 280°C and at a mould temperature of 80°C: dumbbell specimens (thickness 3 mm to ISO 527) - 80 x 10 x 4 mm3 test specimens (to ISO 178) 60 x 60 x 2 mm3 plaques The injection pressure is a processing parameter which was determined during injection moulding of dumbbell specimens. The injection pressure is the internal mould pressure applied close to the gate in order to fill the mould cavity. It is a characteristic inflection point in the curve of pressure as a function of time, between the mould-filling phase and compaction phase, and can be determined by way of process data capture. Except for the melt viscosity measurements and the determination of flow spiral length, the tests listed in the table were carried out on the abovementioned test specimens: Tensile test to determine tensile modulus and tensile stress at break to DIN EN ISO 527-2/1A. Tensile strain at break: extensibility determined to DIN EN ISO 527-2/1A. Flexural test to determine flexural modulus, flexural strength, outer fibre strain, and flexural stress to DIN EN ISO 178. Impact resistance: IZOD method to ISO 180/1U at room temperature and at -30°C. Shrinkage: to determine shrinkage properties, standardized plaques of dimensions 60 mm x 60 mm x 2 mm (ISO 294-4) were injection-moulded. The test then determines longitudinal and transverse shrinkage, both for moulding shrinkage and for after-shrinkage. Total shrinkage is obtained by adding the moulding shrinkage to the after-shrinkage. Flow spiral length: flowability in a flow spiral (thickness 3 mm) was tested on the compounded materials from inventive example and comparative example at a melt temperature of 280°C and at a mould temperature of 80°C. The flow path in cm was measured (flow spiral length). Melt viscosity was determined to DIN 5481 I/ISO 11443 at the stated shear rate and temperature with Viscorobo 94.00 equipment from Gottfert after the pellets had been dried for 48 hours at 80°C in a vacuum dryer. Density was determined by the flotation method on test specimens to DIN EN ISO 1183-1. Surface: The quality of the surface was assessed and estimated visually on test specimens of dimensions 60 mm x 60 mm x 2 mm. The decisive criteria for assessment were gloss, smoothness, colour, and uniform surface structure. WE CLAIM: 1. Moulding compositions comprising A) from 99 to 10 parts by weight of at least one semicrystalline thermoplastic polyamide and B) from 1 to 20 parts by weight of at least one copolymer composed of at least one olefin with at least one methacrylic ester or acrylic ester of an aliphatic alcohol having from 1 to 4 carbon atoms, the MFI of the copolymer B) is from 80 to 900 g/min, characterized in that the MFI has always been measured or determined at 190°C and with a test load of 2.16 kg, the polyamide has been prepared by polycondensation or hydrolytic polymerization and the alkyl group of the methacrylic ester or acrylic ester is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, iso-butyl, tert-butyl. 2. Moulding compositions as claimed in claim 1, wherein less than 4% by weight of the copolymer B) is composed of monomer units which contain further reactive functional groups selected from the group consisting of epoxides, oxetanes, anhydrides, imides, aziridines, furans, acids, amines, oxazolines. 3. Moulding compositions as claimed in claim 1, wherein the olefin is an a- olifin. 4. Moulding compositions as claimed in claim 2, wherein the a- olifin is ethane. 5. Moulding compositions as claimed in claim 1 to 4, wherein if appropriate, also comprise, in addition to A) and B), one or more components of the following series: C) from 0.001 to 70 parts by weight of one filler or reinforcing material, D)) from 0.001 to 65 parts by weight of one flame retardant additive, E) from 0.001 to 80 parts by weight of one elastomer modifier, F) from 0.001 to 10 parts by weight of other conventional additives, G) from 0.5 to 30 parts by weight of compatibilizer. 6. Process for preparation of the polyamide moulding compositions as claimed in claims 1 to 5, wherein the appropriate proportions by weight of the components are mixed. 7. The moulding composition as claimed in any of the preceding claims as and when used for the preparation of mouldings or semifinished products or multitooling systems, for use in the electrical, electronics, telecommunications, motor vehicle, or computer industry, in sports, in medicine, in the household or in the entertainment industry.

Full Text

Polvamide moulding compositions with improved flowabilitv
This invention relates to moulding compositions based on at least one semicrystalline thermoplastic
polyamide and on at least one copolymer composed of at least one olefin, preferably of one a-olefin,
with at least one methacrylic ester or acrylic ester of an aliphatic alcohol having from 1 to 4 carbon
atoms, the MFI (melt flow index) of the copolymer being not less than 50 g/10 min, and to a process
for preparation of these moulding compositions, and also to the use of these moulding compositions
for production of mouldings or of semifinished products via injection moulding or extrusion.
Highly flowable thermoplastic compositions are of interest for a wide variety of injection moulding
applications. By way of example, thin-walled components in the electrical, electronics and motor
vehicle industry require low viscosities from the thermoplastics composition in order to permit
material to be charged to the mould with minimum injection pressures and, respectively, clamping
forces in the appropriate injection moulding machines. This also applies to simultaneous charging of
material to two or more injection moulding components by way of a shared runner system in what
are known as multicavity tooling systems. Shorter cycle times can moreover often be achieved using
low-viscosity thermoplastic compositions. Good flowabilities are also specifically very important for
highly filled thermoplastic compositions, e.g. with glass fibre and/or mineral contents above 40% by
weight.
However, although the thermoplastic compositions have high flowability, the actual components
produced therefrom are subjected to stringent mechanical requirements, and the lowering of viscosity
cannot therefore be permitted to cause significant impairment of mechanical properties.
There are a number of ways of obtaining highly flowable, low-viscosity thermoplastic moulding
compositions.
One way uses low-viscosity polymer resins with very low molecular weight as base polymers for the
thermoplastic moulding compositions. However, the use of low-molecular-weight polymer resins is
often associated with sacrifices in mechanical properties, in particular toughness. Preparation of a
low-viscosity polymer resin in an existing polymerization plant moreover often requires complicated
intervention attended by capital expenditure.
Another way uses what are known as flow aids, also termed flow agents or flow assistants or
internal lubricants, which can be added as an additive to the polymer resin.
These flow aids are known from the literature, e.g. in Kunststoffe 2000, 9, p. 116-118, and by way
of example can be fatty acid esters of polyols, or amides derived from fatty acids and from amines.
However, these fatty acid esters, such as pentaerythritol tetrastearate or ethylene glycol
dimontanoate, have only limited miscibility with polar thermoplastics, such as polyamides,
polyalkylene terephthalates or polycarbonates. Their concentration increases at the surface of the
moulding and they are therefore also used as mould-release aids. However, on heat-ageing or else, in
the case of polyamides, on absorption of moisture, particularly if concentrations are relatively high,
the flow aids can migrate out of these mouldings to the surface and become concentrated there. By
way of example, in coated mouldings this can lead to problems with regard to adhesion to paint or to
metal.
As an alternative to the surface-active flow aids, it is possible to use internal flow aids which are
compatible with the polymer resins. Examples of those suitable for this purpose are low-molecularweight
compounds or branched, highly branched or dendritic polymers whose polarity is similar to
that of the polymer resin. These highly branched or dendritic systems are known from the literature
and their basis can by way of example be branched polyesters, polyamides, polyesteramides,
polyethers or polyamines, as described in Kunststoffe 2001, 91, pp. 179-190, or in Advances in
Polymer Science 1999, 143 (Branched Polymers II), pp. 1-34.
EP-A 0 682 057 describes the use of the nitrogen-containing first-generation 4-cascade dendrimer:
l,4-diaminobutane[4]propylamine (N,N'-tetrabis(3-aminopropyl)-l,4-butanediamine) DAB(PA)4 to
lower viscosity in nylon-6, nylon-6,6 and polybutylene terephthalate (PBT). While use of DAB(PA)4
to lower viscosity in polyamides has practically no effect on the impact resistance of the resultant
moulding compositions (difference PBT.
WO-A 95/06081 (= US 5 493 000) describes the use of three-dimensional branched polymers having
rigid aromatic units in blends with polyamide in order to increase the stiffness of the material and the
ultimate tensile strength, with simultaneous reduction in viscosity and in the tensile strain at break of
the blends.
EP-A 0 994 157 (= AU 6 233 499 A) describes the use of highly branched polymers which are based
on aromatics and which are added during caprolactam polycondensation and are therefore
copolymerized. Compositions composed of polyamides in which highly branched polymers have been
copolymerized exhibit better mechanical properties and better flowabilities here than comparative
compositions without the highly branched components. Addition of the highly branched polymers
during the polymerization reaction is described, but no addition to a polymer melt is described.
In principle, improvements in the flowability of polyamides can also be achieved via addition of
phenols, of bisphenols, and of similar low-molecular-weight additives. EP-A 0 240 887 (= US 5
212 224) describes moulding compositions composed of polyamide, of a rubber and of a bisphenol,
these exhibiting improved flowability brought about via the additive.
DE-A 32 48 329 (= US 4 628 069) describes addition of phenolic compounds to polyamide in order
to reduce water absorption.
Alongside improvement in flowability, it is often desirable to improve the toughness of the materials.
For this, other copolymers which are based on ethene and on acrylic or methacrylic esters and which
bring about an improvement in toughness can also be added to the thermoplastics used.
DE-A 2 758 568 (= US 4 362 846) and DE-A 2 801 585 (= US 4 362 846) describe modification of
the toughness of polyamides with acrylate-grafted polyolefins. It is emphasized that the use of the
acrylate-modified polyolefins leads to an increase in melt viscosity.
EP-A 1 191 067 (= US 6 759 480) describes modification of the toughness of thermoplastics, inter
alia of polyamide and polybutylene terephthalate, via a mixture composed of a copolymer composed
of ethene with an unreactive alkyl acrylate, and also of a copolymer composed of ethene with an
acrylate having an additional reactive group. There is no discussion of the flowability of the
moulding compositions.
The object of the present invention then consisted in lowering the viscosity of polyamide
polycondensate compositions by treating the polymer melt with additives, without any resultant need
to accept the losses that occur when using low-viscosity linear polymer resins or when using
additives disclosed in the literature in properties such as impact resistance and hydrolysis resistance.
In terms of stiffness and ultimate tensile strength, the polyamide compositions should if at all
possible not differ significantly from the polyamide polycondensate compositions not treated with
additives, in order to permit problem-free replacement of the materials for plastic structures based on
polyamide.
Achievement of the object and thus the subject matter of the invention is provided by polyamide
moulding compositions comprising
A) from 99 to 10 parts by weight, preferably from 98 to 30 parts by weight, particularly
preferably from 97 to 60 parts by weight, of at least one semicrystalline thermoplastic
polyamide and
B) from 1 to 20 parts by weight, preferably from 2 to 15 parts by weight, particularly
preferably from 3 to 9 parts by weight, of at least one copolymer composed of at least one
olefin, preferably of one a-olefin, with at least one methacrylic ester or acrylic ester of an
aliphatic alcohol having from 1 to 4 carbon atoms, the MFI of the copolymer B) being not
less than 50 g/10 min, and preferably being from 80 to 900 g/10 min.
For the purposes of the present invention, MFI (melt flow index) has always been measured or
determined at 190°C and with a test load of 2.16 kg.
Surprisingly, it has been found that mixtures composed of at least one semicrystalline thermoplastic
polyamide with copolymers of olefins with methacrylic esters or with acrylic esters of aliphatic
alcohols having from 1 to 4 carbon atoms, their MFI being not less than 50 g/10 min, lead to the
desired lowering of the melt viscosity of the inventive moulding compositions prepared therefrom. In
comparison with moulding compositions without copolymer B), the inventive moulding compositions
exhibit no significant losses, and indeed instead in some cases improvements, in properties such as
low-temperature impact resistance, hydrolysis resistance, density, surface quality. The moulding
compositions have excellent suitability for use in thin-wall technology.
According to the invention, the compositions comprise, as component A), at least one semicrystalline
thermoplastic polyamide.
The polyamides to be used according to the invention can be prepared by various processes and can
be synthesized from very different units, and, in each specific application, can be used alone or can
be treated with processing aids, with stabilizers, with polymeric alloy partners (e.g. elastomers) or
else with reinforcing materials (e.g. mineral fillers or glass fibres) to give materials with specifically
adjusted combinations of properties. Blends with contents of other polymers, e.g. of polyethylene,
polypropylene, ABS (acrylonitrile-butadiene-styrene copolymer) are also suitable, and, if
appropriate, one or more compatibilizers can be used. The properties of the polyamides can be
improved via addition of elastomers, e.g. with regard to the impact resistance of, for example,
reinforced polyamides. The wide variety of possible combinations gives access to a very large
number of products with very different properties.
A wide variety of procedures has been disclosed for preparation of polyamides using, as a function
of the desired final product, different monomer units, a variety of chain regulators in order to set the
desired molecular weight, or else monomers having reactive groups for intended subsequent posttreatments.
The industrially relevant processes for preparation of polyamides mostly proceed by way of
polycondensation in the melt. Hydrolytic polymerization of lactams is also polycondensation for this
purpose.
According to the invention, polyamides preferably to be used as component A) are semicrystalline
polyamides which can be prepared starting from diamines and from dicarboxylic acids and/or from
lactams having fewer than 5 ring members or from corresponding amino acids.
Starting materials which can be used are aliphatic and/or aromatic dicarboxylic acids such as adipic
acid, 2,2,4- and 2,4,4-trimethyladipic acid, azelaic acid, sebacic acid, isophthalic acid, terephthalic
acid, aliphatic and/or aromatic diamines, e.g. tetramethylenediamine, hexamethylenediamine, 1,9-
nonanediamine, 2,2,4- and 2,4,4-trimethylhexamethylenediamine, the isomeric diaminodicyclohexylmethanes,
diaminodicyclohexylpropanes, bisaminomethylcyclohexane, phenylenediamines,
xylylenediamines, aminocarboxylic acids, e.g. aminocaproic acid, and, respectively the
corresponding lactams. Copolyamides composed of two or more of the monomers mentioned are
included.
According to the invention, it is particularly preferable to use caprolactams, and very particularly
preferable to use s-caprolactam, or else most of the compounded materials based on PA6, on PA66 and
on other aliphatic and/or aromatic polyamides and, respectively, copolyamides, where there are from
3 to 11 methylene groups in these materials for each polyamide group in the polymer chain.
The semicrystalline polyamides to be used according to the invention as component A) can also be
used in a mixture with other polyamides and/or with other polymers.
Conventional additives, e.g. mould-release agents, stabilizers and/or flow aids can be admixed with
the polyamides in the melt or can be applied to their surface.
The inventive compositions comprise, as component B), copolymers, preferably random copolymers,
composed of at least one olefin, preferably an a-olefin, and of at least one methacrylic ester or
acrylic ester of an aliphatic alcohol having from 1 to 4 carbon atoms, the MFI of the copolymer B)
being not less than 50 g/10 min, and preferably being from 80 to 900 g/10 min. In one preferred
embodiment, less than 4% by weight, particularly preferably less than 1.5% by weight and very
particularly preferably 0% by weight of the copolymer B) is composed of monomer units which
contain further reactive functional groups (selected from the group consisting of epoxides, oxetanes,
anhydrides, imides, aziridines, furans, acids, amines, oxazolines).
Suitable olefins, preferably a-olefins as constituent of the copolymers B) preferably have from 2 to
10 carbon atoms and can be unsubstituted or have substitution by one or more aliphatic,
cycloaliphatic or aromatic groups.
Preferred olefins have been selected from the group consisting of ethene, propene, 1-butene,
1-pentene, 1-hexene, 1-octene. 3-methyl-l-pentene. Particularly preferred olefins are ethene and
propene, and ethene is very particularly preferred.
Mixtures of the olefins described are also suitable.
In another preferred embodiment, the further reactive functional groups (selected from the group
consisting of epoxides, oxetanes, anhydrides, imides, aziridines, furans, acids, amines, oxazolines) of
the copolymer B) are introduced exclusively by way of the olefins into the copolymer B).
The content of the olefin in the copolymer B) is from 50 to 95% by weight, preferably from 61 to
93% by weight.
The copolymer B) is further defined via the second constituent alongside the olefin. A suitable
second constituent is alkyl esters of acrylic acid or methacrylic acid whose alkyl group is formed by
from 1 to 4 carbon atoms.
By way of example, the alkyl group of the methacrylic or acrylic ester can have been selected from
the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl.
The alkyl group of the methacrylic or acrylic ester is preferably selected from the group consisting of
ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl. Very particularly preferably, the
alkyl group of the methacrylic or acrylic ester has 4 carbon atoms and comprises the n-butyl, secbutyl,
isobutyl or tert-butyl group. Particular preference is given to n-butyl acrylate.
According to the invention, particular preference is given to copolymers B) in which the olefin is
copolymerized with butyl acrylate, in particular n-butyl acrylate.
Mixtures of the acrylic or methacrylic esters described are also suitable. It is preferable here to use
more than 50% by weight, particularly preferably more than 90% by weight and very particularly
preferably 100% by weight, of butyl acrylate, based on the total amount of acrylic and methacrylic
ester in copolymer B).
In another preferred embodiment, the further reactive functional groups (selected from the group
consisting of epoxides, oxetanes, anhydrides, imides, aziridines, furans, acids, amines, oxazolines) of
the copolymer B) are introduced exclusively by way of acrylic or methacrylic esters into the
copolymer B).
The content of the acrylic or methacrylic esters in the copolymer B) is preferably from 5 to 50% by
weight, particularly preferably from 7 to 39% by weight.
A feature of suitable copolymers B) is not only their constitution but also their low molecular weight.
Accordingly, copolymers B) suitable for the inventive moulding compositions are only those whose
MFI value, measured at 190°C and with a load of 2.16 kg, is at least 50 g/10 min, preferably from
80to900g/10min.
Examples of suitable copolymers as component B) can have been selected from the group of the
materials supplied by Arkema (formerly Atofina) with the trade mark Lotryl®, which are usually
used as hot-melt adhesive.
In one preferred embodiment, the inventive polyamide moulding compositions can comprise, in
addition to components A) and B), one or more of the components of the series C), D), E), F) and
G).
In one preferred embodiment of this type, the thermoplastic polyamide moulding compositions can
therefore also, if appropriate, comprise, in addition to components A) and B),
C) from 0.001 to 70 parts by weight, preferably from 5 to 50 parts by weight, particularly
preferably from 9 to 47 parts by weight, of at least one filler or reinforcing material.
However, the filler or reinforcing material used can also comprise mixtures composed of two or
more different fillers and/or reinforcing materials, for example based on talc, mica, silicate, quartz,
titanium dioxide, wollastonite, kaolin, amorphous silicas, magnesium carbonate, chalk, feldspar,
barium sulfate, glass beads and/or fibrous fillers and/or reinforcing materials based on carbon fibres
and/or glass fibres. It is preferable to use mineral particulate fillers based on talc, mica, silicate,
quartz, titanium dioxide, wollastonite, kaolin, amorphous silicas, magnesium carbonate, chalk,
feldspar, barium sulfate and/or glass fibres. It is particularly preferable to use mineral particulate
fillers based on talc, wollastonite, kaolin and/or glass fibres.
Particularly for applications which demand isotropy in dimensional stability and demand high
thermal dimensional stability, for example in motor vehicle applications for exterior bodywork parts,
it is preferable to use mineral fillers, in particular talc, wollastonite or kaolin.
A further particular preference is also the use of acicular mineral fillers, according to the invention,
acicular mineral fillers are a mineral filler with highly pronounced acicular character. An example
which may be mentioned is acicular wollastonites. The lengtkdiameter ratio of the material is
preferably from 2:1 to 35:1, particularly preferably from 3:1 to 19:1, most preferably from 4:1 to
12:1. The average particle size of the inventive acicular minerals is preferably smaller than 20 urn,
particularly preferably smaller than 15 (im, with particular preference smaller than 10 um,
determined using a CILAS GRANULOMETER.
As previously described above, the filler and/or reinforcing material may, if appropriate, have been
surface-modified, for example using a coupling agent or coupling agent system, e.g. based on silane.
However, the pretreatment is not absolutely essential. In particular when glass fibres are used,
polymer dispersions, film-formers, branching agents and/or glass fibre processing aids can also be
used in addition to silanes.
The glass fibres to be used with particular preference according to the invention whose fibre
diameter is generally from 7 to 18 um, preferably from 9 to 15 um, are added in the form of
continuous-filament fibres or in the form of chopped or ground glass fibres. The fibres can have been
equipped with a suitable size system and with a coupling agent or coupling agent system, e.g. based
on silane.
Familiar coupling agents based on silane for pretreatment are silane compounds having by way of
example the general formula (I)
(I) (X-(CH2)q)k-Si-(0-CrH2r+1)4.k
where the substituents are as follows:
X: NH2-,HO-or H2c^-^c—,
H
q: a whole number from 2 to 10, preferably from 3 to 4,
r: a whole number from 1 to 5, preferably from 1 to 2, and
k: a whole number from 1 to 3, preferably 1.
Preferred coupling agents are silane compounds from the group of aminopropyltrimethoxysilane,
aminobutyltrimethoxysilane, aminopropyltriethoxysilane, aminobutyltriethoxysilane, and also the
corresponding silanes which contain a glycidyl group as substituent X.
The amounts generally used of the silane compounds for equipping the fillers are from 0.05 to 2% by
weight, preferably from 0.25 to 1.5% by weight and in particular from 0.5 to 1% by weight, based
on the mineral filler used for surface coating.
The consequence of processing to give the moulding composition or moulding is that the d97 or d50
value of the particulate fillers in the moulding composition or in the moulding can be smaller than
that of the fillers initially used. A consequence of the processing to give the moulding composition or
moulding is that the length distributions of the glass fibres in the moulding composition or in the
moulding can be shorter than those of the material initially used.
In one alternative preferred embodiment, the polyamide moulding compositions can also, if
appropriate, comprise, in addition to components A) and B), and/or C),
D) from 0.001 to 65 parts by weight of at least one flame retardant additive.
Flame retardants that can be used in component D) are commercially available organic halogen
compounds with synergists or are commercially available organic nitrogen compounds or are
organic/inorganic phosphorus compounds individually or in a mixture. It is also possible to use
mineral flame retardant additives such as magnesium hydroxide or Ca Mg carbonate hydrates (e.g.
DE-A 4 236 122 (= CA 210 9024 Al)). It is also possible to use salts of aliphatic or of aromatic
sulphonic acids. Examples which may be mentioned of halogen-containing, in particular brominated
and chlorinated compounds are: ethylene-l,2-bistetrabromophthalimide, epoxidized
tetrabromobisphenol A resin, tetrabromobisphenol A oligocarbonate, tetrachlorobisphenol A
oligocarbonate, pentabromopolyacrylate, brominated polystyrene and decabromodiphenyl ether.
Examples of suitable organophosphorus compounds are the phosphorus compounds according to
WO-A 98/17720 (= US 6 538 024), e.g. triphenyl phosphate (TPP), resorcinol bis(diphenyl
phosphate) (RDP) and the oligomers derived therefrom, and also bisphenol A bis(diphenyl
phosphate) (BDP) and the oligomers derived therefrom, and organic and inorganic phosphonic acid
derivatives and salts thereof, organic and inorganic phosphinic acid derivatives and salts thereof, in
particular metal dialkylphosphinates, e.g. aluminium tris[dialkylphosphinates] or zinc
bisfdialkylphosphinates] and moreover red phosphorus, phosphites, hypophosphites, phospine
oxides, phosphazenes, melamine pyrophosphate and mixtures of these. Nitrogen compounds which
can be used are those from the group of the allantoin derivatives, cyanuric acid derivatives,
dicyandiamide derivatives, glycoluril derivatives, guanidine derivatives, ammonium derivatives and
melamine derivatives, preferably allantoin, benzoguanamine, glycoluril, melamine, condensates of
melamine, e.g. melem, melam or melom and, respectively, higher-condensation-level compounds of
this type and adducts of melamine with acids, e.g. with cyanuric acid (melamine cyanurate),
phosphoric acid (melamine phosphate) or with condensed phosphoric acids (e.g. melamine
polyphosphate). Examples of suitable synergists are antimony compounds, in particular antimony
trioxide, sodium antimonate and antimony pentoxide, zinc compounds, e.g. zinc borate, zinc oxide,
zinc phosphate and zinc sulphide, tin compounds, e.g. tin stannate and tin borate, and also
magnesium compounds, e.g. magnesium oxide, magnesium carbonate and magnesium borate. The
materials known as carbonizers can also be added to the flame retardant, examples being phenolformaldehyde
resins, polycarbonates, polyphenyl ethers, polyimides, polysulphones, polyether
sulphones, polyphenylene sulphides and polyether ketones, and also antidrip agents, such as
tetrafluoroethylene polymers.
In a further alternative preferred embodiment, the polyamide moulding compositions can also, if
appropriate, comprise, in addition to components A) and B), and/or C) and/or D),
E) from 0.001 to 80 parts by weight, particularly preferably from 2 to 25 parts by weight, of at
least one elastomer modifier.
The elastomer modifiers to be used as component E) encompass one or more graft polymers of
E.I from 5 to 95% by weight, preferably from 30 to 90% by weight, of at least one vinyl
monomer,
E.2 from 95 to 5% by weight, preferably from 70 to 10% by weight, of one or more graft bases
with glass transition temperatures The median particle size (dso value) of the graft base E.2 is generally from 0.05 to 10 jam, preferably
from 0.1 to 5 um, particularly preferably from 0.2 to 1 um.
Monomers E. 1 are preferably mixtures composed of
E. 1.1 from 50 to 99% by weight of vinylaromatics and/or ring-substituted vinylaromatics (such as
styrene, a-methyl styrene, p-methyl styrene, p-chlorostyrene) and/or (Ci-Cs)-alkyl
methacrylates (e.g. methyl methacrylate, ethyl methacrylate) and
E.I.2 from 1 to 50% by weight of vinyl cyanides (unsaturated nitriles, such as acrylonitrile and
methacrylonitrile) and/or (d-C8)-alkyl (meth)acrylates (e.g. methyl methacrylate, n-butyl
acrylate, tert-butyl acrylate) and/or derivatives (such as anhydrides and imides) of
unsaturated carboxylic acids (e.g. maleic anhydride and N-phenylmaleimide).
Preferred monomers E.I.I have been selected from at least one of the monomers styrene,
ot-methylstyrene and methyl methacrylate, and preferred monomers E.I.2 have been selected from at
least one of the monomers acrylonitrile, maleic anhydride and methyl methacrylate.
Particularly preferred monomers are E. 1.1 styrene and E. 1.2 acrylonitrile.
Examples of suitable graft bases E.2 for the graft polymers to be used in the elastomer modifiers E)
are diene rubbers, EP(D)M rubbers, i.e. rubbers based on ethylene/propylene and, if appropriate,
diene, acrylate rubbers, polyurethane rubbers, silicone rubbers, chloroprene rubbers and ethylenevinyl
acetate rubbers.
Preferred graft bases E.2 are diene rubbers (e.g. based on butadiene, isoprene, etc.) or mixtures of
diene rubbers, or are copolymers of diene rubbers or of their mixtures with further copolymerizable
monomers (e.g. according to E. 1.1 and E. 1.2), with the proviso that the glass transition temperature
of component E.2 is Examples of particularly preferred graft bases E.2 are ABS polymers (emulsion, bulk and
suspension ABS), as described by way of example in DE-A 2 035 390 (= US-A 3 644 574) or in
DE-A 2 248 242 (= GB-A 1 409 275) or in Ullmann, Enzyklopadie der Technischen Chemie
[Encyclopaedia of Industrial Chemistry], Vol. 19 (1980), pp. 280 et seq. The gel content of the graft
base E.2 is preferably at least 30% by weight, particularly preferably at least 40% by weight
(measured in toluene).
The elastomer modifiers or graft polymers E) are prepared via free-radical polymerization, e.g. via
emulsion, suspension, solution or bulk polymerization, preferably via emulsion or bulk
polymerization.
Other particularly suitable graft rubbers are ABS polymers which are prepared via redox initiation
using an initiator system composed of organic hydroperoxide and ascorbic acid according to US-A
4937285.
Because it is known that the graft monomers are not necessarily entirely grafted onto the graft base
during the grafting reaction, products which are obtained via (co)polymerization of the graft
monomers in the presence of the graft base and are produced concomitantly during the work-up are
also graft polymers B according to the invention.
Suitable acrylate rubbers are based on graft bases E.2 which are preferably polymers composed of
alkyl acrylates, if appropriate with up to 40% by weight, based on E.2, of other polymerizable,
ethylenically unsaturated monomers. Among the preferred polymerizable acrylic esters are Ci-C8-
alkyl esters, such as methyl, ethyl, butyl, n-octyl and 2-ethylhexyl esters; haloalkyl esters, preferably
halo-Ci-Cg-alkyl esters, such as chloroethyl acrylate, and also mixtures of these monomers.
For crosslinking, monomers having more than one polymerizable double bond can be copolymerized.
Preferred examples of crosslinking monomers are esters of unsaturated monocarboxylic acids having
from 3 to 8 carbon atoms and of unsaturated monohydric alcohols having from 3 to 12 carbon
atoms, or of saturated polyols having from 2 to 4 OH groups and from 2 to 20 carbon atoms, e.g.
ethylene glycol dimethacrylate, allyl methacrylate; polyunsaturated heterocyclic compounds, e.g.
trivinyl and triallyl cyanurate; polyfunctional vinyl compounds, such as di- and trivinylbenzenes; and
also triallyl phosphate and diallyl phthalate.
Preferred crosslinking monomers are allyl methacrylate, ethylene glycol dimethacrylate, diallyl
phthalate and heterocyclic compounds which have at least 3 ethylenically unsaturated groups.
Particularly preferred crosslinking monomers are the cyclic monomers triallyl cyanurate, triallyl
isocyanurate, triacryloylhexahydro-s-triazine, triallylbenzenes. The amount of the crosslinking
monomers is preferably from 0.02 to 5% by weight, in particular from 0.05 to 2% by weight, based
on the graft base E.2.
In the case of cyclic crosslinking monomers having at least 3 ethylenically unsaturated groups, it is
advantageous to restrict the amount to below 1% by weight of the graft base E.2.
Examples of preferred "other" polymerizable, ethylenically unsaturated monomers which can serve
alongside the acrylic esters, if appropriate, for preparation of the graft base E.2 are acrylonitrile,
styrene, a-methylstyrene, acrylamides, vinyl d-C6-alkyl ethers, methyl methacrylate, butadiene.
Acrylate rubbers preferred as graft base E.2 are emulsion polymers whose gel content is at least
60% by weight.
Further suitable graft bases according to E.2 are silicone rubbers having sites active for grafting
purposes, as described in DE-A 3 704 657 (= US 4 859 740), DE-A 3 704 655 (= US 4 861 831),
DE-A 3 631 540 (= US 4 806 593) and DE-A 3 631 539 (= US 4 812 515).
Alongside elastomer modifiers based on graft polymers, it is also possible to use, as component E),
elastomer modifiers not based on graft polymers but having glass transition temperatures preferably lastomers with block copolymer structure. Among these can also be, by way of example, elastomers
which can undergo thermoplastic melting. Preferred materials mentioned here by way of example are
EPM rubbers, EPDM rubbers and/or SEES rubbers.
In a further alternative preferred embodiment, the polyamide moulding compositions can also, if
appropriate, comprise, in addition to components A) and B), and/or C) and/or D) and/or E),
F) from 0.001 to 10 parts by weight, preferably from 0.05 to 3 parts by weight, of other
conventional additives.
For the purposes of the present invention, examples of conventional additives are stabilizers (e.g. UV
stabilizers, heat stabilizers, gamma-ray stabilizers), antistatic agents, flow aids, mould-release
agents, further fire-protection additives, emulsifiers, nucleating agents, plasticizers, lubricants, dyes,
pigments and additives for increasing electrical conductivity. The additives mentioned and further
suitable additives are described by way of example in Gachter, Miiller, Kunststoff-Additive [Plastics
Additives], 3rd Edition, Hanser-Verlag, Munich, Vienna, 1989 and in Plastics Additives Handbook,
5th Edition, Hanser-Verlag, Munich, 2001. The additives may be used alone or in a mixture, or in
the form of masterbatches.
Examples of stabilizers which can be used are sterically hindered phenols, hydroquinones, aromatic
secondary amines, e.g. diphenylamines, substituted resorcinols, salicylates, benzotriazoles and
benzophenones, and also various substituted representatives of these groups and mixtures thereof.
Examples of pigments and dyes which can be used are titanium dioxide, zinc sulphide, ultramarine
blue, iron oxide, carbon black, phthalocyanines, quinacridones, perylenes, nigrosin and
anthraquinones.
Examples of nucleating agents which can be used are sodium phenylphosphinate or calcium
phenylphosphinate, aluminium oxide, silicon dioxide, and also preferably talc.
Examples of lubricants and mould-release agents which can be used are ester waxes, pentaerythritol
tetrastearate (PETS), long-chain fatty acids (e.g. stearic acid or behenic acid) and esters, salts
thereof (e.g. Ca stearate or Zn stearate), and also amide derivatives (e.g. ethylenebisstearylamide) or
montan waxes (mixtures composed of straight-chain, saturated carboxylic acids having chain lengths
of from 28 to 32 carbon atoms), and also low-molecular-weight polyethylene waxes and
polypropylene waxes.
Examples of plasticizers which can be used are dioctyl phthalate, dibenzyl phthalate, butyl benzyl
phthalate, hydrocarbon oils, N-(n-butyl)benzenesulphonamide.
Additives which can be added to increase electrical conductivity are carbon blacks, conductivity
blacks, carbon fibrils, nanoscale graphite fibres and nanoscale carbon fibres, graphite, conductive
polymers, metal fibres, and also other conventional additives for increasing electrical conductivity.
Nanoscale fibres which can preferably be used are those known as "single-wall carbon nanorubes"
or "multiwall carbon nanotubes" (e.g. from Hyperion Catalysis).
In a further alternative preferred embodiment, the polyamide moulding compositions can also, if
appropriate, comprise, in addition to components A) and B), and/or C), and/or D), and/or E), and/or
F),
G) from 0.5 to 30 parts by weight, preferably from 1 to 20 parts by weight, particularly
preferably from 2 to 10 parts by weight, and most preferably from 3 to 7 parts by weight, of
compatibilizer.
Compatibilizers used preferably comprise thermoplastic polymers having polar groups.
According to the invention, polymers used are therefore those which contain
G. 1 a vinylaromatic monomer,
G.2 at least one monomer selected from the group of C2-Ci2-alkyl methacrylates, C2-Ci2-
alkyl acrylates, methacrylonitriles and acrylonitriles and
G.3 dicarboxylic anhydrides containing a,p-unsaturated components.
The component G used preferably comprises terpolymers of the monomers mentioned. Accordingly,
it is preferable to use terpolymers of styrene, acrylonitrile and maleic anhydride. In particular, these
terpolymers contribute to improvement in mechanical properties, such as tensile strength and tensile
strain at break. The amount of maleic anhydride in the terpolymer can vary widely. The amount is
preferably from 0.2 to 5 mol%. Amounts of from 0.5 to 1.5 mol% are particularly preferred. In this
range, particularly good mechanical properties are achieved in relation to tensile strength and tensile
strain at break.
The terpolymer can be prepared in a known manner. One suitable method is to dissolve monomer
components of the terpolymer, e.g. styrene, maleic anhydride or acrylonitrile, in a suitable solvent,
e.g. methyl ethyl ketone (MEK). One or, if appropriate, more chemical initiators are added to this
solution. Examples of suitable initiators are peroxides. The mixture is then polymerized at elevated
temperatures for a number of hours. The solvent and the unreacted monomers are then removed in a
manner known per se.
The ratio of component G.I (vinylaromatic monomer) to component G.2, e.g. the acrylonitrile
monomer in the terpolymer is preferably from 80:20 to 50:50.
Styrene is particularly preferred as vinylaromatic monomer G. 1.
Acrylonitrile is particularly preferably suitable for component G.2.
Maleic anhydride is particularly preferably suitable as component G.3.
EP-A 0 785 234 (= US 5 756 576) and EP-A 0 202 214 (= US 4 713 415) describe examples of
compatibilizers G) which can be used according to the invention. According to the invention,
particular preference is given to the polymers mentioned in EP-A 0 785 234.
The compatibilizers can be present in component G) alone or in any desired mixture with one
another.
Another substance particularly preferred as compatibilizer is a terpolymer of styrene and
acyrlonitrile in a ratio of 2.1:1 by weight containing 1 mol% of maleic anhydride. Component G) is
used particularly when the moulding composition comprises graft polymers, as described under E).
According to the invention, the following combinations of the components are preferred:
A,B;A,B,C; A,B,D; A,B,E; A,B,F; A,B,G; A,B,C,D; A,B,C,E; A,B,C,F; A,B,C,G;
A,B,D,E; A,B,D,F; A,B,D,G; A,B,E,F; A,B,E,G; A,B,F,G; A,B,C,D,E; A,B,C,D,F;
A,B,C,D,G; A,B,C,E,F; A,B,C,E,G; A,B,C,F,G; A,B,E,F,G; A,B,D,E,F; A,B,D,E,G;
A,B,D,F,G; A,B,C,D,E,F; A,B,C,D,E,G; A,B,C,D,F,G; A,B,D,E,F,G; A,B,C,E,F,G;
A,B,C,D,E,F,G.
The present invention further provides the preparation of the inventive polyamide moulding
compositions. This takes place by known processes via mixing of the components in the appropriate
proportions by weight. The mixing of the components preferably takes place at temperatures of from
220 to 330°C by combining, mixing, kneading, extruding or rolling the components together. It can
be advantageous to premix individual components. It can moreover be advantageous to produce
mouldings or semifinished products directly from a physical mixture (dry blend) which has been
prepared at room temperature (preferably from 0 to 40°C) and which is composed of premixed
and/or individual components.
The invention further provides the mouldings or semifinished products to be produced from the
inventive polyamide moulding compositions comprising
A) from 99 to 10 parts by weight, preferably from 98 to 30 parts by weight, particularly
preferably from 97 to 60 parts by weight, of at least one semicrystalline thermoplastic
polyamide and
B) from 1 to 20 parts by weight, preferably from 2 to 15 parts by weight, particularly
preferably from 3 to 9 parts by weight, of at least one copolymer composed of at least one
olefin, preferably of one a-olefin, with at least one methacrylic ester or acrylic ester of an
aliphatic alcohol having from 1 to 4 carbon atoms, the MFI being not less than 50 g/10 min
and preferably being from 80 to 900 g/10 min.
Further advantages surprisingly exhibited by the inventive moulding compositions in comparison
with the prior art are the following:
markedly improved flowability, in particular at shear rates relevant for thermoplastics
processing;
markedly reduced injection pressure in processing via injection moulding;
improved low temperature impact resistance;
lower density;
improved hydrolysis resistance;
improved surface quality of the mouldings.
The inventive polyamide moulding compositions can be processed by conventional processes, for
example via injection moulding or extrusion, to give mouldings or semifinished products. Examples
of semifinished products are foils and sheets. Particular preference is given to processing via
injection moulding.
The mouldings or semifinished products to be produced according to the invention from the
polyamide moulding compositions can be small or large parts and, by way of example, can be used
in the motor vehicle, electrical, electronics, telecommunications, information technology, or computer
industry, in the household, in sports, in medicine or in the entertainment industry. In particular, the
inventive polyamide moulding compositions can be used for applications which require high melt
flowability. An example of these applications is what is known as thin-wall technology, in which the
wall thicknesses of mouldings to be produced from the moulding compositions are less than 2.5 mm,
preferably less than 2.0 mm, particularly preferably less than 1.5 mm and most preferably less than
1.0mm. Another example of these applications is cycle time reduction, e.g. via reduction of
processing temperature. Another application example is the processing of the moulding compositions
by way of what are known as multitooling systems, in which material is charged by way of a runner
system to at least 4 moulds, preferably at least 8 moulds, particularly preferably at least 12 moulds,
most preferably at least 16 moulds, in an injection moulding procedure.
Mouldings composed of the inventive moulding compositions can also be used for parts of the
cooling circulation system and/or of the oil circulation system of motor vehicles.
Examples:
The following were used:
Nylon-6: Durethan® B29, commercially available product from Lanxess Deutschland GmbH,
Leverkusen, Germany, with relative solution viscosity 2.9 (measured in m-cresol at 25°C)
Glassfibre: Glassfibre sized with silane-containing compounds and with diameter 11 um (CS 7928,
commercially available product from Lanxess N.V., Antwerp, Belgium)
Lotryl® 28 BA 175: Copolymer composed of ethene and n-butyl acrylate with ethene content of 70-
74% by weight and MFI of 175 (commercially available product from Atofina Deutschland,
Dusseldorf; since October 2004 Arkema GmbH, Dusseldorf)
The compositions based on PA6 were compounded in a ZSK32 (Werner and Pfleiderer) twin-screw
extruder at melt temperatures of from 270 to 285°C to give moulding compositions, and the melt
was discharged into a water bath and then pelletized.
The test specimens for the tests listed in the table were injection-moulded in an Arburg 320-210-500
injection-moulding machine at a melt temperature of 280°C and at a mould temperature of 80°C:
dumbbell specimens (thickness 3 mm to ISO 527)
- 80 x 10 x 4 mm3 test specimens (to ISO 178)
60 x 60 x 2 mm3 plaques
The injection pressure is a processing parameter which was determined during injection moulding of
dumbbell specimens. The injection pressure is the internal mould pressure applied close to the gate in
order to fill the mould cavity. It is a characteristic inflection point in the curve of pressure as a
function of time, between the mould-filling phase and compaction phase, and can be determined by
way of process data capture.
Except for the melt viscosity measurements and the determination of flow spiral length, the tests
listed in the table were carried out on the abovementioned test specimens:
Tensile test to determine tensile modulus and tensile stress at break to DIN EN ISO 527-2/1A.
Tensile strain at break: extensibility determined to DIN EN ISO 527-2/1A.
Flexural test to determine flexural modulus, flexural strength, outer fibre strain, and flexural stress
to DIN EN ISO 178.
Impact resistance: IZOD method to ISO 180/1U at room temperature and at -30°C.
Shrinkage: to determine shrinkage properties, standardized plaques of dimensions
60 mm x 60 mm x 2 mm (ISO 294-4) were injection-moulded. The test then determines longitudinal
and transverse shrinkage, both for moulding shrinkage and for after-shrinkage. Total shrinkage is
obtained by adding the moulding shrinkage to the after-shrinkage.
Flow spiral length: flowability in a flow spiral (thickness 3 mm) was tested on the compounded
materials from inventive example and comparative example at a melt temperature of 280°C and at a
mould temperature of 80°C. The flow path in cm was measured (flow spiral length).
Melt viscosity was determined to DIN 5481 I/ISO 11443 at the stated shear rate and temperature
with Viscorobo 94.00 equipment from Gottfert after the pellets had been dried for 48 hours at 80°C
in a vacuum dryer.
Density was determined by the flotation method on test specimens to DIN EN ISO 1183-1.
Surface: The quality of the surface was assessed and estimated visually on test specimens of
dimensions 60 mm x 60 mm x 2 mm. The decisive criteria for assessment were gloss, smoothness,
colour, and uniform surface structure.

WE CLAIM:
1. Moulding compositions comprising
A) from 99 to 10 parts by weight of at least one semicrystalline thermoplastic polyamide and
B) from 1 to 20 parts by weight of at least one copolymer composed of at least one olefin with at least one methacrylic ester or acrylic ester of an aliphatic alcohol having from 1 to 4 carbon atoms, the MFI of the copolymer B) is from 80 to 900 g/min, characterized in that the MFI has always been measured or determined at 190°C and with a test load of 2.16 kg, the polyamide has been prepared by polycondensation or hydrolytic polymerization and the alkyl group of the methacrylic ester or acrylic ester is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, iso-butyl, tert-butyl.
2. Moulding compositions as claimed in claim 1, wherein less than 4% by weight of the
copolymer B) is composed of monomer units which contain further reactive functional groups
selected from the group consisting of epoxides, oxetanes, anhydrides, imides, aziridines, furans,
acids, amines, oxazolines.
3. Moulding compositions as claimed in claim 1, wherein the olefin is an a- olifin.
4. Moulding compositions as claimed in claim 2, wherein the a- olifin is ethane.
5. Moulding compositions as claimed in claim 1 to 4, wherein if appropriate, also comprise, in addition to A) and B), one or more components of the following series:
C) from 0.001 to 70 parts by weight of one filler or reinforcing material, D)) from 0.001 to 65 parts by weight of one flame retardant additive,
E) from 0.001 to 80 parts by weight of one elastomer modifier,
F) from 0.001 to 10 parts by weight of other conventional additives,
G) from 0.5 to 30 parts by weight of compatibilizer.

6. Process for preparation of the polyamide moulding compositions as claimed in claims 1 to 5,
wherein the appropriate proportions by weight of the components are mixed.
7. The moulding composition as claimed in any of the preceding claims as and when used for the preparation of mouldings or semifinished products or multitooling systems, for use in the electrical, electronics, telecommunications, motor vehicle, or computer industry, in sports, in medicine, in the household or in the entertainment industry.

Documents:

2223-DEL-2006-Abstract-(30-07-2010).pdf

2223-del-2006-abstract.pdf

2223-del-2006-Claims (24-11-2011).pdf

2223-DEL-2006-Claims-(30-07-2010).pdf

2223-del-2006-claims.pdf

2223-DEL-2006-Correspondence-Others-(30-07-2010).pdf

2223-del-2006-correspondence-others.pdf

2223-del-2006-description (complete).pdf

2223-DEL-2006-Form-1-(30-07-2010).pdf

2223-del-2006-form-1.pdf

2223-DEL-2006-Form-2-(30-07-2010).pdf

2223-del-2006-form-2.pdf

2223-del-2006-form-3.pdf

2223-del-2006-form-5.pdf

2223-DEL-2006-GPA-(30-07-2010).pdf

2223-del-2006-gpa.pdf

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Patent Number

250023

Indian Patent Application Number

2223/DEL/2006

PG Journal Number

48/2011

Publication Date

02-Dec-2011

Grant Date

29-Nov-2011

Date of Filing

09-Oct-2006

Name of Patentee

LANXESS DEUTSCHLAND GMBH

Applicant Address

D-51369 LEVERKUSEN,GERMANY

Inventors:

#	Inventor's Name	Inventor's Address
1	DETLEV JOACHIMI	SCHEIBLERSTR.103,D-47800 KREFELD,GERMANY
2	MATTHIAS BIENMULLER	JOSEF-LENDERS-DYK 15 D-47803 KREFELD,GERMANY
3	JOCHEN ENDTNER	SUEVENSTR.6,D-50679 KOLN,GERMANY
4	RALPH ULRICH	GUSTAV-LINDEN-STR 35,D-40878 RATINGEN,GERMANY
5	PETER PERSIGEHL	VENICE AREA 42,WUXI TAIHU VENICE GARDEN WUXI JIANGSU 214121,CHINA,
6	STEFANIE KLINGENHOFER	WALTER-FLEX-STR.37, D-47809 KREFELD,GERMANY

PCT International Classification Number

C08L79/02; C08L33/08; C08L79/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10 2005 050 958.4	2005-10-25	Germany