DE9205402U1 - Impact-resistant thermoplastic molding compounds - Google Patents

Description

BASF Aktiengesellschaft 910830 °· ^&Zgr; · 0050/« 160

Impact-resistant thermoplastic molding compounds

Description 5 The invention relates to impact-resistant thermoplastic molding compositions, containing

A) 10 to 75 wt.% of a thermoplastic polyamide 10

B) 20 to 85% by weight of a modified polyphenylene ether, which may be replaced by up to 40% by weight, based on B), by a vinyl aromatic polymer,

15 C) 0.2 to 2.8 wt.% of a copolymer composed of

80 to 99.5 wt.% styrene and/or substituted styrenes of the general formula I

RC= _CH2

where R and R ¹ represent identical or different alkyl groups having 1 to 8 C atoms and/or halogen atoms and η is 0, 1, 2 or 3.

C2) 0.5 to 10 wt.% of an α,ß-unsaturated dicarbonyl compound

C3) 0 to 19.5 wt.% of other comonomers 35

D) 0 to 20 wt.% of an impact modifier rubber

E) 0 to 60% by weight of other additives in effective amounts,

where the weight percentages A) to E) add up to 100%.

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Furthermore, the invention relates to the use of such molding compositions for producing moldings and to moldings obtainable from the molding compositions according to the invention as essential components.
5

EP-A 46 040 and EP-A 281 916 disclose molding compositions based on polyphenylene ethers and polyamides which contain a copolymer which has units of vinylaromatic monomers and α,β-unsaturated dicarboxylic acid anhydrides or imides.

According to the examples, copolymers are used whose content of dicarboxylic anhydride or diimide is generally more than 8, in particular at least 10 mol%. 15

These molding compounds show unsatisfactory toughness for applications, particularly for automotive exterior parts.

EP-A 147 87 4 describes thermoplastic molding compositions made from 20 polyphenylene ethers and polyamides, which contain a copolymer of vinyl aromatic monomers and α,β-unsaturated dicarboxylic acids, the dicarboxylic acid content in the monomer mixture being 41 to 50 mol%. The copolymer is added in an amount of 0.1 to 1.9% by weight to the compositions made from 25 polyamides and polyphenylene ethers.

These known masses have the disadvantage that they have only a low flowability, which has a disruptive effect on injection molding.

WO 87/0540 discloses a process for producing PPE/PA blends, whereby the polyphenylene ether is pre-modified with α,β-unsaturated dicarbonyl compounds and then mixed with polyamide, thereby producing a

to achieve better compatibility between both polymers.

Impact modifiers for blends of modified PPE/PPA are known from EP-A 234 063, 234 593 and 236 596.

The toughness of these molding compounds needs improvement for some applications.

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The present invention was therefore based on the object of providing impact-resistant thermoplastic PPE/PPA molding compounds which have good toughness properties, in particular good multiaxial impact strength. 5

According to the invention, this object is achieved by the thermoplastic molding compounds defined at the outset.

Preferred masses of this type are set out in subclaim 10.

As component A), the molding compositions according to the invention contain 10 to 75, preferably 25 to 60 and in particular 30 to 50 % by weight of a thermoplastic polyamide.

The polyamides used as component A) are known per se and include the semi-crystalline and amorphous resins with molecular weights (weight average) of at least 5000, which are usually referred to as nylon. Such polyamides

20 Lyamides are described, for example, in the American patents 2 071 250, 2 071 251, 2 130 523, 2 130 948, 2 241 322, 2 312 966, 2 512 606 and 3 393 210.

The polyamides can be produced, for example, by condensing equimolar amounts of a saturated or aromatic dicarboxylic acid with 4 to 12 carbon atoms, with a saturated or aromatic diamine which has up to 14 carbon atoms or by condensing μ)-aminocarboxylic acids or polymerizing lactams. 30

Examples of polyamides are polyhexamethylene adipamide (nylon 66), polyhexamethylene azelaamide (nylon 69), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecanedioamide (nylon 612), the polyamides obtained by ring opening of lactams such as polycaprolactam (nylon 6), polylauric acid lactam, also poly-11-aminoundecanoic acid and a polyamide of di(p-aminocyclohexyl)methane and dodecanedioic acid.

It is also possible to use polyamides according to the invention which have been prepared by copolycondensation of two or more of the above-mentioned monomers or their components, e.g. copolymers of adipic acid, isophthalic acid

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or terephthalic acid and hexamethylenediamine (polyamide 66/6T) or copolymers of caprolactam, terephthalic acid and hexamethylenediamine (polyamide 6/6T). Such partially aromatic copolyamides contain 40 to 90% by weight of units derived from terephthalic acid and hexamethylenediamine. A small proportion of the terephthalic acid, preferably not more than 20% by weight of the total aromatic dicarboxylic acids used, can be replaced by isophthalic acid or other aromatic dicarboxylic acids, preferably those in which the carboxyl groups are in the para position.

In addition to the units derived from terephthalic acid and hexamethylenediamine, the partially aromatic copolyamides contain units derived from ε-caprolactam and/or units derived from adipic acid and hexamethylenediamine.

The proportion of units derived from ε-caprolactam is up to 50% by weight, preferably 20 to 50% by weight, in particular 25 to 40% by weight, while the proportion of units derived from adipic acid and hexamethylenediamine is up to 60% by weight, preferably 30 to 60% by weight and in particular 35 to 55% by weight.

The copolyamides can also contain units of ε-caprolactam as well as units of adipic acid and hexamethylenediamine; in this case, care must be taken to ensure that the proportion of units that are free of aromatic groups is at least 10% by weight, preferably at least

30 20 wt.%. The ratio of units differing from

ε-caprolactam and from adipic acid and hexamethylenediamine, is not subject to any particular restriction.

Polyamides with 50 to 80, in particular 60 to 75 wt.% units derived from terephthalic acid and hexamethylenediamine and 20 to 50, preferably 25 to 40 wt.% units derived from ε-caprolactam have proven to be particularly advantageous for many applications.

Compositions of 50 to 70 wt.% units derived from terephthalic acid and hexamethylenediamine and 10 to 20 wt.% units derived from adipic acid and hexamethylenediamine have proven to be particularly advantageous for ternary copolyamides.

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diamine and 20 to 30 wt.% units derived from isophthalic acid and hexamethylenediamine.

5 The partially aromatic copolyamides can be prepared, for example, by the process described in EP-A-129 195 and EP 129 196.

Linear polyamides with a melting point 10 above 200 ^° C are preferred.

Preferred polyamides are polyhexamethylene adipamide, polyhexamethylene sebacamide and polycaprolactam as well as polyamide 6/6T and polyamide 66/6T. The polyamides have

generally have a relative viscosity of 2.0 to 5, determined on a 0.5 wt.% solution in 96% sulfuric acid at 2 5°C, which corresponds to a molecular weight of about 15,000 to 45,000. Polyamides with a relative viscosity of 2.4 to 3.5, in particular 2.5 to 3.4 are

20 is preferred.

Polyamides should also be mentioned which are obtainable, for example, by condensation of 1,4-diaminobutane with adipic acid at elevated temperatures (polyamide-4,6). Production processes for polyamides of this structure are described, for example, in EP-A 38 094, EP-A 38 582 and EP-A 39 524.

Mixtures of the above-mentioned polyamides can also be used.
30

As component B), the molding compositions according to the invention contain 20 to 85, preferably 30 to 70, in particular 35 to 60 wt.% of a modified polyphenylene ether.

The polyphenylene ethers generally have a molecular weight (weight average) in the range from 10,000 to 80,000, preferably from 20,000 to 60,000.

This corresponds to a reduced specific viscosity Tlred ^of 0/2 to 0.9 dl/g, preferably 0.35 to 0.8 and in particular 0.45 to 0.6, measured in a 1 wt.% solution in chloroform at 25°C according to DIN 53 72 6.

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The unmodified polyphenylene ethers fc>i) are known per se and are preferably prepared by oxidative coupling of phenols disubstituted in the o-position.

Examples of substituents are halogen atoms such as chlorine or bromine and alkyl radicals with 1 to 4 carbon atoms, which preferably do not have a tertiary hydrogen atom in the α position, e.g. methyl, ethyl, propyl or butyl radicals. The alkyl radicals can in turn be substituted by halogen atoms such as chlorine or bromine or by a hydroxyl group. Other examples of possible substituents are alkoxy radicals, preferably with up to 4 carbon atoms or phenyl radicals optionally substituted by halogen atoms and/or alkyl groups. Copolymers of various phenols such as copolymers of 2,6-dimethylphenol and 2,3,6-trimethylphenol are also suitable. Of course, mixtures of various polyphenylene ethers can also be used.

Preferably, polyphenylene ethers are used which are compatible with vinylaromatic polymers, i.e. are completely or largely soluble in these polymers (cf. A. Noshay, Block Copolymers, pp. 8 to 10, Academic Press, 1977 and 0. Olabisi, Polymer-Polymer Miscibility, 1979, p. 117

25 to 189).

Examples of polyphenylene ethers are poly(2,6-dilauryl-1,4-phenylene ether), poly(2,6-diphenyl-1,4-phenylene ether), poly(2,6-dimethoxy-1,4-phenylene ether), poly(2,6-di-

30 ethoxy-1,4-polyphenylene ether), poly(2-methoxy-6-ethoxy-1,4-phenylene ether), poly(2-ethyl-6-stearyloxy-1,4-phenylene ether), poly-(2,6-dichloro-1,4-phenylene ether) , poly(2-methyl-6-phenyl-1,4-phenylene ether, poly(2,6-dibenzyl-1,4-phenylene) ether,

Poly(2-ethoxy-l,4-phenylene ether), poly(2-chloro-l,4-phenylene ether) , poly(2,5-dibromo-l,4-phenylene ether). Polyphenylene ethers are preferably used in which the substituents are alkyl radicals with 1 to 4 carbon atoms, such as poly(2,6-dimethyl-l,4-phenylene ether), poly(2,6-di-

40 ethyl-1,4-phenylene ether), poly(2-methyl-6-ethyl-l,4-phenylene ether) , poly(2-methyl-6-propyl-l,4-phenylene ether),

BASF Aktiengesellschaft 910830 OZ 0050/43160

Poly(2,6-dipropyl-1,4-phenylene ether) and poly(2-ethyl-6-propyl-1,4-phenylene ether).

Graft copolymers made from polyphenylene ether and 5 vinylaromatic monomers such as styrene, ct-methylstyrene, vinyltoluene and chlorostyrene are also suitable.

Functionalized or modified polyphenylene ethers B) are known per se, e.g. from WO-A 86/02086, WO-A 87/00540, EP-A-222 246, EP-A-223 116 and EP-A-254 048.

Usually, the polyphenylene ether bi) is modified by incorporating at least one carbonyl, carboxylic acid, acid anhydride, acid amide, acid imide, carboxylic acid ester, carboxylate, amino, hydroxyl, epoxy, oxazoline, urethane, urea, lactam or halobenzyl group, so that sufficient compatibility with the second polymer of the mixture, the polyamide, is ensured.

The modification is generally carried out by reacting a polyphenylene ether bi) with a modifier which contains at least one of the above-mentioned groups, in solution (WO-A 86/2086), in aqueous dispersion, in a gas phase process (EP-A-25 200) or in the melt, optionally in the presence of suitable vinyl aromatic polymers or impact modifiers, where optionally radical initiators can be present.

Suitable modifiers (b ₃ ) are, for example, maleic acid, methylmaleic acid, itaconic acid, tetrahydrophthalic acid, their anhydrides and imides, fumaric acid, the mono- and diesters of these acids, e.g. of Ω- and C2-Cs-alkanols (monomers b3i), the mono- or diamides of these acids such as N-phenylmaleimide (monomers b ₃ 2), maleic hydrazide. Other modifiers are the acid chloride of trimelitic anhydride, benzene-1,2-dicarboxylic anhydride-4-carboxylic acid-acetic anhydride, chloroethanoylsuccinaldehyde, chloroformylsuccinaldehyde, citric acid and hydroxysuccinic acid. Examples of monomers b ₃₃ ) are N-vinylpyrrolidone and (meth)acryloylcaprolactam.

BASF Aktiengesellschaft 910830

O.Z. 0050/43160

Preferably, in the molding compositions according to the invention, as component B) a modified polyphenylene ether is used which is obtained by reacting

bi) 59.95 to 99.95 wt.% of an unmodified polyphenylene ether,

b2) 0 to 40 wt.% of a vinyl aromatic polymer,

b3> 0.05 to 5 wt.% of at least one compound from the group consisting of

b3i) an α,ß-unsaturated dicarbonyl compound,

b32> of an amide group-containing monomer with a polymerizable double bond and

a lactam group-containing monomer with a polymerizable double bond, 20

0 to 5 wt.% of a radical initiator

where the percentages by weight refer to the sum of bi) to b,j), is obtainable in the course of 0.5 to 15 minutes at 240 to 375°C in suitable mixing and kneading units such as twin-screw extruders.

The vinyl aromatic polymer (b2> should preferably be compatible with the polyphenylene ether used.

The molecular weight of these polymers, which are known per se, is generally in the range from 1500 to 2 000 000, preferably in the range from 70 000 to 1 000 000, particularly preferably in the range from 75 000 to 200 000.

Examples of preferred vinylaromatic polymers compatible with polyphenylene ethers can be found in the already mentioned monograph by Olabisi, pp. 224 to 230 and 245. Vinylaromatic polymers made from styrene, chlorostyrene, a-methylstyrene and p-methylstyrene are mentioned here only as examples; in minor proportions (preferably not more than 20, in particular not more than 8% by weight), comonomers such as (meth)acrylonitrile or

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(Meth)acrylic acid esters may be involved in the structure. Particularly preferred vinyl aromatic polymers are polystyrene and impact-modified polystyrene. It goes without saying that mixtures of these polymers can also be used. 5 The preparation is preferably carried out according to the process described in EP-A-302 485.

Radical initiators (b ₄ ) include:

10 Di-(2,4-dichlorobenzoyl)peroxide, tert-butylperoxide,

Di-(3,5,5-trimethylhexanol)peroxide, dilauroyl peroxide, didecanoyl peroxide, dipropionyl peroxide, dibenzoyl peroxide,
tert-butyl peroxy-2-ethylhexoate, tert-butyl peroxydiethyl acetate, tert-butyl peroxyisobutyrate, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy-3,3,5-trimethylhexoate, tert-butyl peracetate, tert-butyl perbenzoate, 4,4-di-tert-butylperoxyvaleric acid butyl ester, 2,2-ditert-butylperoxybutane, dicumyl peroxide, tert-butylcumyl peroxide, 1,3-di(tert-butylperoxyisopropyl)benzene and di-tert-butyl peroxide. Also mentioned are organic hydroperoxides such as di-isopropylbenzene monohydroperoxide, cumene hydroperoxide, tert-butyl hydroperoxide, p-menthyl hydroperoxide and pinane hydroperoxide as well as highly branched alkanes of the general structure

R4 Rl
R ⁵ CCR ²

30 ^{R6 R3}

where R ¹ to R ⁶ are alkyl groups with 1-8 C atoms, alkoxy groups with 1-8 C atoms, aryl groups such as phenyl, naphthyl or 5- or 6-membered heterocycles with a

p-electron system and nitrogen, oxygen or sulfur as heteroatoms. The substituents R ¹ to R ⁶
can in turn contain functional groups as substituents
such as carboxyl, carboxyl derivative, hydroxyl,
Amino, thiol or epoxide groups. Examples are 2,3-di-

methyl-2,3-diphenylbutane, 3,4-dimethyl-3,4-diphenylhexane and 2,2,3,3-tetraphenylbutane.

BASF Aktiengesellschaft 910830 OZ 0050/43160

10

As essential component C), the molding compositions according to the invention contain in amounts of 0.2 to 2.8, preferably 0.5 to 2.5 and in particular 1 to 2.5 wt.% of a copolymer of
5

80 to 99.5 wt.% styrene and/or substituted styrene

len of the general formula I

RC= _CH2 10

(I]

15 where R and R ¹ are the same or different alkyl

groups with 1 to 8 C atoms, hydrogen and/or halogen atoms and

η is 0, 1, 2 or 3,

C ₂ ) 0.5 - 10 wt.% of an α,ß-unsaturated dicarbonyl compound

and 25 C3) 0 to 19.5 wt.% of other comonomers.

Among the substituted styrenes of the general formula I, a-methylstyrene and &rgr;-methylstyrene are particularly preferred, but the various ethylstyrenes and chlorostyrenes (m-, o-, p-) are also suitable, to name just a few. The proportion of component Ci is 80 to 99.5, preferably 90 to 99% by weight, based on C).

In principle, all α,β-unsaturated dicarbonyl compounds, in particular α,β-unsaturated dicarboxylic acids or their anhydrides, half esters, esters, amides or imides or mixtures thereof, are suitable as component C ₂ ).

Examples include maleic acid, maleic anhydride, half esters of maleic acid with alcohols with 1-8 C atoms, especially with 1-4 C atoms, and the corresponding fully esterified maleic acid derivatives. Preferred

BASF Aktiengesellschaft 910830 0· ^&zgr; · 0050/43160

Examples of the last two groups are maleic acid monomethyl ester and maleic acid dimethyl ester, of which the former is particularly preferred.

Other dicarboxylic acids that can be used as such or in the form of their corresponding derivatives are fumaric acid, chloromaleic acid, dichloromaleic acid, methylmaleic acid, butenylsuccinic acid and tetrahydrophthalic acid.
10

Examples of imides are maleimide or N-phenylmaleimide.

The proportion of monomer C2) is 0.5 - 10, preferably 1 to 9 wt.%, based on the total weight of components Ci + C2) and optionally C3).

As component C3), up to 19.5% by weight, preferably up to 5% by weight, of other comonomers can be used. Products that do not interfere with the adjustment of the particle morphology are particularly preferred. Examples of these are methyl acrylate, acrylonitrile and methacrylonitrile. In general, it has proven advantageous to omit component C3).

The molecular weight (weight average) of the copolymers C) is generally in the range from 10,000 to 2,000,000, preferably from 40,000 to 300,000.

The copolymers C) used according to the invention can be prepared in a manner known per se by bulk, solution, emulsion or suspension polymerization, either continuously or batchwise. The monomers are preferably polymerized in a suitable solvent, such as ethylbenzene. In a particularly preferred embodiment, the monomers, eg styrene and maleic anhydride, are polymerized at 120 to 150 ^° C with a radical initiator or, in particular, thermally, ie without a radical initiator, continuously at elevated pressure. In

40 In a very preferred embodiment, Ci) and C2) are continuously reacted thermally at about 140 ^° C, about 10 bar pressure and about 6 h residence time.

BASF Aktiengesellschaft 910830 OZ 0050/43160

In addition to the essential components A) to C), the molding compositions according to the invention can contain 0 - 20, preferably 4-15% by weight, and in particular 6 to 12% by weight of an impact-modifying rubber. Conventional impact modifiers D) can be used which are suitable for polyamides (component A) and rubbers D) which usually impact-modify polyphenylene ethers B).

Component D) consists of the usual impact-modifying polymers (also called impact modifiers, elastomers or rubbers) used to improve the toughness of polyamides or polyphenylene ethers.

Examples of rubbers that increase the toughness of polyphenylene ethers include the following:

Polyoctenylenes, graft rubbers with a cross-linked, elastomeric core, which is derived from butadiene, isoprene or alkyl acrylates, for example, and a graft shell made of polystyrene, as well as copolymers of ethylene and acrylates or methacrylates, as well as the so-called ethylene-propylene (EP) and ethylene-propylene-diene (EPDM) rubbers, and also the EP or EPDM rubbers grafted with styrene.

25 Block copolymers with up to six, preferably with up to

four identical or different blocks, which can be connected either linearly or in a star shape (so-called radial block copolymers), have proven to be particularly suitable.

Preference is given to block rubbers in which at least one block, preferably an end block, is made up of vinylaromatic monomers such as styrene, Ct-methylstyrene, vinyltoluene, vinyl or isopropenylnaphthalene. Polystyrene as vinylaromatic

35 romantic block is especially preferred.

Usually, these preferred block copolymers also contain an elastomeric block which is characterized by a glass transition temperature of less than 0 ⁰ C, preferably less than -30 ⁰ C. This block is derived, for example, from conjugated dienes such as butadiene, isoprene, 1,3-pentadiene or 2,3-dimethylbutadiene. In order to obtain products with good long-term heat resistance, it has proven particularly useful to

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particularly suitable if at least 50%, preferably at least 80% and in particular at least 90% of the double bonds are hydrogenated.

The transitions between the individual blocks can be both sharp and blurred.

Preferably, the rubbers that increase the toughness of polyphenylene ethers are linear block

10 copolymers of the general structure A-B, A-B-A' or

A-B-A'-B', where A and A' represent the vinylaromatic block, preferably polystyrene, and B and B' represent the elastomeric block, which preferably consists of butadiene and/or isoprene - where both butadiene and isoprene can be hydrogenated

15 can - is built up.

Mixtures of block copolymers of different structures, e.g. mixtures of two- and three-block copolymers or of hydrogenated and unhydrogenated block copolymers, can also be used.

Such impact-modifying polymers are known per se and described in the literature. For example, reference is made here to US-A 4 085 163, US-A 4 041 103, US-A 3 149 182, US-A 3 231 635 and US-A 3 462 162.

Corresponding products are also commercially available, e.g. a polyoctylene called Vestenamer® (Hüls AG), as well as a large number of suitable block copolymers with at least one vinyl aromatic and one elastomeric block. Examples include the Cariflex®-TR types (Shell), the Kraton®-G types (Shell), the Finaprene® types (Fina) and the Europrene®-SOL-TR types (Enichem).

Rubbers that increase the toughness of polyamides generally have two essential features: they contain an elastomeric portion that has a glass transition temperature of less than -10 ⁰ C, preferably less than -30 ⁰ C, and they contain at least one functional group that can react with the polyamide. Suitable functional groups are, for example, carboxylic acid, carboxylic acid anhydride, carbon

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acid ester, carboxylic acid amide, carboxylic acid imide, amino, hydroxyl, epoxy, urethane and oxazoline groups.

Examples of rubbers that increase the toughness of polyamides include:

EP or EPDM rubbers that have been grafted with the functional groups mentioned above. Suitable grafting reagents include maleic anhydride, itaconic acid, acrylic acid, glycidyl acrylate and glycidyl methacrylate. These monomers can be grafted onto the polymer in the melt or in solution, optionally in the presence of a radical initiator such as cumene hydroperoxide.

Copolymers of a-olefins should also be mentioned. The Ct-olefins are usually monomers with 2 to 8 C atoms, preferably ethylene and propylene. Alkyl acrylates or alkyl methacrylates, which are derived from alcohols with 1 to 8 C atoms, preferably

20 of ethanol, butanol or ethylhexanol, and

reactive comonomers such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride or glycidyl (meth)acrylate and also vinyl esters, especially vinyl acetate, have proven to be suitable. Mixtures of different comonomers can also be used. Copolymers of ethylene with ethyl or butyl acrylate and acrylic acid and/or maleic anhydride have proven to be particularly suitable.

The copolymers can be produced in a high-pressure process at a pressure of 400 to 4500 bar or by grafting the comonomers onto the poly-α-olefin. The proportion of α-olefin in the copolymer is generally in the range of 99.95 to 55% by weight.

Another group of suitable elastomers is core-shell graft rubbers. These are graft rubbers produced in emulsion and consisting of at least one hard and one soft component. A hard component is usually understood to mean

40 a polymer with a glass transition temperature of at least 25°C, a soft component a polymer with a glass transition temperature of at most 0 ⁰ C. These products have a structure consisting of a core and at least one

BASF Aktiengesellschaft 910830 &ogr;.&Zgr;. 0050/43160

Shell, whereby the structure is usually determined by the order in which the monomers are added. The soft components are generally derived from butadiene, isoprene, alkyl acrylates or alkyl methacrylates and optionally other comonomers. Suitable comonomers here include styrene, acrylonitrile and crosslinking or grafting monomers with more than one polymerizable double bond such as diallyl phthalate, divinylbenzene, butanediol diacrylate or triallyl (iso)cyanurate. The hard components are generally derived from styrene, α-methylstyrene and their copolymers, whereby the preferred comonomers here are acrylonitrile, methacrylonitrile and methyl methacrylate.

Preferred core-shell graft rubbers contain a

soft core and a hard shell or a hard core, a first soft shell and at least one further hard shell. The incorporation of functional groups such as carbonyl, carboxylic acid, acid anhydride, acid amide, acid imide, carboxylic acid ester, amino, hydroxyl, epoxy, oxazoline, urethane, urea, lactam or halobenzyl groups is preferably carried out by adding suitable functionalized monomers during the polymerization of the last shell. Suitable functionalized monomers are, for example, maleic acid, maleic anhydride, mono- or diesters of maleic acid, tertiary butyl (meth)acrylate, acrylic acid, glycidyl (meth)acrylate and vinyloxazoline. The proportion of monomers with functional groups is generally 0.1 to 25% by weight, preferably 0.25 to 15% by weight, based on the total weight of the core-shell graft rubber. The weight ratio of soft to hard components is generally 1:9 to 9:1, preferably 3:7 to 8:2.

Such rubbers, which increase the toughness of polyamides, are known per se and are described, for example, in EP-A 208 187.

Another group of suitable impact modifiers are thermoplastic polyester elastomers. Polyester elastomers are understood to be segmented copolyether esters, which contain long-chain segments, which are usually derived from poly(alkylene) ether glycols, and short-chain segments, which are derived from low-molecular diols and dicarboxylic acids. Such products are known per se

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and described in the literature, e.g. in US-A 3 651 014. Corresponding products are also available commercially under the names Hytrel® (Du Pont), Arnitel® (Akzo) and Pelprene® (Toyobo Co. Ltd.). 5

Of course, mixtures of different rubbers can also be used.

In addition to the essential components A) to C) and optionally D), the molding compositions according to the invention can contain 0 to 60, preferably up to 35 wt.% of other additives E) in effective amounts.

As component E), the molding compositions according to the invention can contain 0 to 45, preferably 10 to 40% by weight of fibrous or particulate fillers or mixtures thereof. Examples of fillers include carbon or glass fibers in the form of glass fabrics, glass mats or glass silk rovings, glass beads and wollastonite.

Preferred fibrous reinforcing materials (component E) are carbon fibers, potassium titanate whiskers, aramid fibers and particularly preferably glass fibers. When glass fibers are used, they can be treated with a size and an adhesion promoter to improve compatibility with the thermoplastic polyamide (A) or the modified polyphenylene ether (B). In general, the carbon and glass fibers used have a diameter in the range of 6 to 20 (µm).

These glass fibers can be incorporated in the form of short glass fibers or in the form of continuous strands (rovings). In the finished injection molded part, the average length of the glass fibers is preferably in the range of 0.08 to 0.5 mm.

Suitable particulate fillers (component E) are amorphous silica, asbestos, magnesium carbonate (chalk), powdered quartz, mica, talc, feldspar and in particular calcium silicates such as wollastonite and kaolin (in particular

40 calcined kaolin).

BASF Aktiengesellschaft 910830 OZ 0050/43160

Preferred combinations of fillers are, for example, 20 wt.% glass fibers with 15 wt.% wollastonite and 15 wt.% glass fibers with 15 wt.% wollastonite.

The molding compositions according to the invention can further contain flame retardants E) in amounts of 0 to 20% by weight, preferably up to 12% by weight, based on the total weight of the molding compositions.

All known flame retardants can be used, such as polyhalodiphenyl, polyhalodiphenyl ether, polyhalophthalic acid and their derivatives, polyhalooligo- and polycarbonates, with the corresponding bromine compounds being particularly effective.

Particularly preferred is 1,2,3,4,7,8,9,10,13,13,14,14-dodecachloro-1,4,4a,5,6,6a,7,10,10a,11,12,12a-dodecahydro-1,4:7,10-dimethanodibenzo(a,e)-cyclooctane (Dechlorane®Plus, Occidental Chemical Corp.) and optionally

20 if a synergist, e.g. antimony trioxide.

Other phosphorus compounds are red phosphorus or organophosphorus compounds such as phosphonates, phosphinates, phosphinites, phosphine oxides, phosphines, phosphites or 25 phosphates are also preferred. Triphenylphosphine oxide is an example.

Typical preferred phosphorus compounds are those of the following general formula 30 0

QO P OQ

OQ

where Q represents hydrogen or identical or different hydrocarbon radicals or halogenated hydrocarbon radicals, such as alkyl, cycloalkyl, aryl, alkyl-substituted aryl and aryl-substituted alkyl, provided that at least one of the radicals representing Q is an aryl radical. Examples of such suitable phosphates are, for example, the following: phenylbisdodecyl phosphate, phenylbisneopentyl phosphate, phenylethylene hydrogen phosphate, phenyl-bis-(3-5,5'-trimethyl-

BASF Aktiengesellschaft 910830 OZ 0050/43160

hexyl phosphate), ethyl diphenyl phosphate, 2-ethylhexyl di(p-toluyl) phosphate, diphenyl hydrogen phosphate, bis-(2-ethylhexyl)phenyl phosphate, tri(nonylphenyl) phosphate, phenylmethyl hydrogen phosphate, di(dodecyl)-p-tolyl phosphate, tri-5 cresyl phosphate, triphenyl phosphate, dibutylphenyl phosphate and diphenyl hydrogen phosphate. The preferred phosphates are those where each Q is aryl. The most preferred phosphate is triphenyl phosphate.

Compounds that contain phosphorus-nitrogen bonds are also suitable as flame retardants, such as phosphonitrile chloride, phosphoric acid ester amides, phosphoric acid ester amines, phosphoric acid amides, phosphonic acid amides, phosphinic acid amides, tris(aziridinyl)phosphine oxide or

Tetrakis(hydroxymethyl)phosphonium chloride. This contains

Most flame retardant additives are commercially available.

Other halogen-containing flame retardants are tetrabromobenzene, hexachlorobenzene and hexabromobenzene as well as halogenated polystyrenes and polyphenylene ethers.

The halogenated phthalimides described in DE-A-19 4 6 92 4 can also be used. Of these, N,N'-ethylenebistetrabromophthalimide has gained particular importance.

Other common additives E) are, for example, stabilizers and oxidation inhibitors, agents against heat decomposition

Settlement and decomposition by ultraviolet light, sliding

and mold release agents, dyes, pigments and plasticizers. Their proportion is generally up to 20, preferably up to 10% by weight, based on the total weight of the components A) to E).

Oxidation retarders and heat stabilizers that can be added to the thermoplastic masses according to the invention are, for example, halides of metals from group I of the periodic table, e.g. sodium, potassium, lithium halides,

possibly in combination with copper(I) halides, e.g.

Chlorides, bromides or iodides. Zinc fluoride and zinc chloride can also be used.
sterically hindered phenols, hydroquinones, substituted

BASF Aktiengesellschaft 910830 O ₁ Z. 0050/43160

Representatives of this group and mixtures of these compounds can be used, preferably in concentrations of up to 1% by weight, based on the weight of the mixture.

Examples of UV stabilizers are various substituted resorcinols, salicylates, benzotriazoles and benzophenones, which are generally used in amounts of up to 2 wt.%.

Materials to increase the shielding against electromagnetic waves, such as metal flakes, powders, fibers, metal-coated fillers and conductive polymers can be used.

Lubricants and mold release agents, which are usually added in amounts of up to 1% by weight of the thermoplastic mass, are stearic acid, stearyl alcohol, stearic acid alkyl esters and amides, and esters of pentaerythritol with long-chain fatty acids.

The thermoplastic molding compositions according to the invention are advantageously obtained by mixing the individual components at temperatures of 270 to 350 ^° C in conventional mixing devices such as kneaders, Banbury mixers and single-screw extruders, but preferably with a twin-screw extruder. In order to obtain a molding composition that is as homogeneous as possible, intensive mixing is necessary. The mixing sequence of the components can be varied; two or, if appropriate, three components can be premixed, but all components can also be mixed together.

The reinforcing agents are usually not dosed into the feed, but preferably in another zone of the extruder.

The molding compounds according to the invention are characterized by their balanced properties, in particular by their good impact strength and puncture resistance. 40

They are particularly suitable for the production of molded articles by injection molding or extrusion as well as blow molding, especially for thermally stressed parts in the automotive industry.

BASF Aktiengesellschaft 910830 °· ^&Zgr; · 0050/43 160

area. In the latter area of application, it is particularly advantageous that the parts produced from the molding compositions according to the invention exhibit a ductile fracture pattern due to their toughness.
5

Examples

The following components were used:

10 Component Al Poly-S-caprolactam (PA6) with a viscosity number of 190 ml/g.

Component A2

Polyhexamethylene adipamide (PA66) with a viscosity number of 140 ml/g (determined according to DIN 53727 as a 1 wt.% solution in 96 wt.% sulfuric acid at 25°C).

Component B

A modified polyphenylene ether was prepared at 300 ⁰ C in a twin-screw extruder by reacting

99 wt.% poly(2,6-dimethyl-1,4-phenylene ether) with !!red ⁼ 0.48 dl/g (determined as 1 wt.% solution in 25 chloroform at 25°C) and b3i) 1 wt.% fumaric acid.

The melt was degassed, extruded, passed through a water bath and granulated.
30

Component B'

An unmodified poly(2,6-dimethyl-l,4-phenylene ether) with

an r\ _red = 0.58 dl/g.

35 Component C

The copolymers have the composition given in Table 1 as well as the melt volume index (MVI) at 200°C/5 kg load according to DIN 53735:

BASF Aktiengesellschaft

910830

O.Z. 0050/43160

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Table 1

Styrene Ci) Maleic anhydride C2) MVI (200°C/5kg) C/l 94 6 4 C/2 92 8th 10 C/3 97.5 2.5 25 C/4*) 87 13 17

for comparison

Component D)

A styrene-butadiene-styrene three-block polymer containing 30% by weight polystyrene (Cariflex® TRIlOl, from Shell AG).

Production of the moulding compounds

Components A) to D) were mixed on a twin-screw extruder at a cylinder temperature of 290 ⁰ C and processed to a homogeneous melt. The polymer melt was degassed, extruded, passed through a water bath, granulated and dried.

The dried granules were then injection molded into standard test specimens at 280 ^° C.

The notched impact strength a& was measured according to DIN 53453, the Izod impact strength according to ISO 180 A and the puncture energy (Ws) according to DIN 53443.

The composition of the molding compounds and their properties can be found in Table 2.

BASF Aktiengesellschaft

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Table 2: Examples 1-4 and comparative examples (V-I - V-V)

Components V-I V-II ¹ ) V-III ² ) V-IV ¹ ) 1 - 2 3 4 V-V 5 Al (PA 6) - - - - 47 47 47 40 47 47 A2 (PA66) 47 47 47 47 - - - - - - B' (unmodified polyethylene ether) 42 38 - - 40 - - - - - B (in|imodified polyethylene ether) - - 42 38 11 40.5 40.5 47 40.5 40 D Rubber 11 11 11 11 - 10 10 11 10 11 C 1 (S/MSA 94/6) - - - - - 2.5 - - - - C 2 (S/MSA 92/8) - - - - 2 - 2.5 - - - C 3 (S/MSA 97.5/2.5) - 4 - 4 - - - 2 - 2 C 4 (V) (S/MSA 87/13) - - - - 35 - - - 2.5 - a _K RT kJ/m ² 1.2 6.6 26 28 11 75 70 61 - 74 _aK -30°C kJ/m ² 0.3 1.9 8th 7 55 - - - - - IZOD RT kJ/m ² 2.4 5.3 37 32 62 79 64 52 - 70 Wg Nm 0.7 1.5 43 44 55 59 53 22 51

= EP 281 916 = WO 87/540

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Claims (1)

BASF Aktiengesellschaft 910830 ^{0<Z< 005} ° ^/431dO Protection claims 1. Impact-modified thermoplastic molding compositions containing 5 A) 10 to 75 wt.% of a thermoplastic polyamide B) 20 to 85% by weight of a modified polyphenylene ether which may contain up to 40% by weight, based on B), 10 may be replaced by a vinyl aromatic polymer, C) 0.2 to 2.8 wt.% of a copolymer composed of 15 Ci) 80 to 99.5 wt.% styrene and/or sub substituted styrenes of the general formula I RC= _CH2 ²⁰ '- (D, where R and R ¹ are identical or different alkyl groups having 1 to 8 C atoms and/or halogen atoms and η is 0, 1, 2 or 3. C2) 0.5 to 10 wt.% of an α,ß-unsaturated dicarbonyl compound C3) 0 to 19.5 wt.% of other comonomers 35 D) 0 to 20 wt.% of an impact modifier rubber 40 830/91 Sch/mb 16.04.1992 BASF Aktiengesellschaft 910830 OZ 0050/43160 E) 0 to 60% by weight of other additives in effective amounts, where the weight percentages A) to E) add up to 100%. 2. Impact-resistant thermoplastic molding compositions according to claim 1, corresponding A) 10 - 75 wt.% B) 20 - 85 wt.% C) 0.2-2.8 wt.% D) 4 - 15 wt.% 15 3. Impact-resistant thermoplastic molding compositions according to claims 1 or 2, characterized in that the polyphenylene ether B) is obtainable by reacting bi) 59.95 - 99.95 wt.% of a polyphenylene ether, 20 0-40 wt.% of a vinyl aromatic polymer, 0.05 to 5 wt.% of at least one compound from the group consisting of 25 an α,ß-unsaturated dicarbonyl compound, of a monomer containing amide groups with a polymerizable double bond and 30 a lactam group-containing monomer with a polymerizable double bond, 4 0 to 5 wt.% of a radical initiator 35 where the weight percentages refer to the sum of to b^) over a period of 0.5 to 15 minutes at 240 to 375°C. 40 4. Impact-resistant molding compositions according to claim 3, characterized in that component b3> is maleic acid, maleic anhydride or fumaric acid. BASF Aktiengesellschaft 910830 &ogr;.&Zgr;. 0050/43160 5. Impact-resistant thermoplastic molding compositions according to claims 1 to 4, in which component C) is a copolymer composed of 5 Ci) 90 - 99.5 wt.% styrene and C2) 0.5 - 10 wt.% of an α,β-unsaturated dicarboxylic acid or its anhydrides. 10 6. Impact-resistant thermoplastic molding compositions according to claims 5, characterized in that component C2) is maleic acid, maleic anhydride, fumaric acid, itaconic acid or mixtures thereof.