CA2066106A1

CA2066106A1 - Stabilized thermoplastic partly aromatic polyamide molding compositions

Info

Publication number: CA2066106A1
Application number: CA002066106A
Authority: CA
Inventors: Walter Goetz; Michael Kopietz; Gerd Blinne
Original assignee: Individual
Current assignee: BASF SE
Priority date: 1991-04-16
Filing date: 1992-04-15
Publication date: 1992-10-17
Also published as: EP0509282A3; DE4112324A1; ATE140712T1; DE59206799D1; EP0509282A2; ES2090392T3; JPH05171037A; EP0509282B1

Abstract

O.Z. 0050/42361 Abstract of the Disclosure: Thermoplastic molding com-positions contain A) 40-99.9 % by weight of a partly aromatic and partly crystalline copolyamide having a triamine content of less than 0.5 % by weight composed of (A1) 20-90 % by weight of units derived from tereph-thalic acid and hexamethylenediamine, (A2) 0-50 % by weight of units derived from ?-caprolactam, (A3) 0-80 % by weight of units derived from adipic acid and hexamethylenediamine, (A4) 0-40 % by weight of further polyamide-forming monomers, the proportion of component (A2) or (A3) or (A4) or a mixture thereof being not less than 10 % by weight, B) 0.1-2 % by weight of at least one aromatic secondary amine, and C) 100-2000 ppm of at least one phosphorus-containing inorganic acid or a derivative thereof, the proportion of component C) being based on the total amount of components A) and B), and also D) 0-59.9 % by weight of a fibrous or particulate filler or a mixture thereof, E) 0-30 % by weight of an elastomeric polymer.

Description

O.Z. 0050/42361 Stabilized thermoplastic partlv aromatic PolYamide moldinq comeositions The pre~ent invention relates to thermoplastic molding compositions containing A) 40-99.9 % by weight of a partly aromatic and partly crystalline copolyamide having a triamine content of le~s than 0.5 % by weight composed of (Al) 20-90 ~ by weight of units derived from tereph-thalic acid and hexamethylenediamine, (A2) 0-50 % by weight of units derived from 6-caprolactam, (A3) 0-80 % by weight of units deri~ed from adipic acid and hexamethylenediamine, (A4) 0-40 % by weight of further polyamide-forming monomers, the proportion of component (A2) or (A3) or (A4) or a mixture thereof being not less than 10 % by weight, B) 0.1-2 % by weight of at least one aromatic secondary amine, and C) 100-2000 ppm of at least one phosphorus-containing inorganic acid or a derivative thereof, the proportion of component C) being based on the total amount of components A) and B), and also D) 0-59.9 % by weight of a fibrous or particulate filler or a mixture thereof, E) 0-30 ~ by weight of an elastomeric polymer.
The present invention also relates to the use of such partly aromatic copolyamides for producing fibers, films, sheets and molding3 and to the shaped articles obtainable from these partly aromatic copolyamides.
The stabilization of polyamide~ to oxidative and thermal degradation largely determines the possible uses of the3e polymers. Usually these stabilization systems also confer adequate protection against light.
EP-A-281 691, JP-A-63/142059, DE-A-2 643 204 and DE-A-2 516 565 disclose stabilizers based on copper iodide and potassium iodide for partly crystalline . ~

2~6610~
- 2 - O.Z. 0050/42361 aliphatic polyamides.
The further possibility of stabilizing these partly crystalline aliphatic polyamides with 2terically hindered phenols i9 known from DE-A-2 522 833. The combination of these phenols with other compounds is known from the following publications: DE-A-2 158 014 (phosphorus-containing compounds~ and NL-A-8 602 807 (aromatic amine compounds).
GB-A-1 030 363 discloses nitrogen compounds combined with tran~ition metal amine complexes as stabil-izing system for partly crystalline aliphatic polyamide~.
Additionally, JP-A-63/105 057 discloses a stabil-izing system for partly aromatic but amorphous polyamides comprising a copper compound and phenolic or phosphorus-containing compounds with or without thioethers and aminecompound~.
Furthermore, CA-A-963 594 discloses a ~tabilizer combination of an aromatic amine and a phosphorus-containing compound for partly crystalline aliphatic polyamides.
Copolyamides which are partly aromatic and partly crystalline have the advantage of possessing a higher heat deflection temperature (and hence require higher processing temperatures). Consequently, these polyamides are used wherever a high sustained-use temperature in air is required (eg. electricals).
However, the prior art stabilizers are not usable for these polyamides, since for example copper compounds catalyze the degradation of polyamides in the course of processing. Phenolic antioxidants are likewise not suitable, since these compounds decompose when processed in an extruder at high temperatures.
Moreover, only a small proportion of the starting amount remains behind in the molding composition itself, since these compounds are too volatile at the processing temperatures customary for partly aromatic copolyamides.
Aromatic amine compounds generally have the ` 20~6106 - 3 - O.Z. 0050/42361 di~advantage that effective ~tabilization requires relatively large quantities, ~o that their u~e i~ not economical. Moreover, they have an adverse effect on the mechanical properties of the polyamide articles.
In addition, the problem with partly aromatic and partly cryqtalline copolyamide~ i8 that adequate oxida-tive and thermal stabilization do not guarantee effective light stabilization, since the aromatic moietie~ have a severe impairing effect on the light stability.
It iR an object of the present invention to provide a stabilizing ~y~tem for partly aromatic and partly crystalline copolyamides which ensures good thermal and oxidative stabilization at high proces ing temperature~.
We have found that this object i9 achieved by the molding compositions defined at the beginning. Preferred molding compo~ition~ of thi4 kind are revealed in the subclaims.
AR component A) the thermopla~tic molding compo-sitions of the pre~ent invention contain from 40 to 99.9, preferably from 50 to 99.5, in particular from 70 to 99.7, % by weight of a partly aromatic and partly cry~talline copolyamide having a triamine content of below 0.5 % by weight, preferably below 0.3 % by weight, composed of:
A~) 20 - 90 % by weight of unit~ derived from tereph-thalic acid and hexamethylenediamine, A2) 0 - 50 % by weight of unit~ derived from e-caprO-lactam, and A3) 0 - 80 ~ by weight of unit~ derived from adipic acid and hexamethylenediamine, A4) 0 - 40 % by weight of further poly d de-forming monomer~, the proportion of component (A2) or (A3) or (A4~ or mixture~ thereof being at least 10 % by weight.
Component ~l) contain~ 20 - 90 % by weight of unitq derived from terephthalic acid and hexamethylene-2066~0~

- 4 - O.Z. 0050/42361 dlamine .
In addition to units derived from terephthalic acid and hexamethylenediamine, the copolyamides contain units derived from ~-caprolactam and/or units derived from adipic acid and hexamethylenediamine and/or units derived from further polyamide-forming monomer~.
The proportion of unit~ derived from -caprolac-tam i~ not more than 50 ~ by weight, preferably from 20 to 50 % by weiyht, in particular from 25 to 40 % by weight, while the proportion of units derived from adipic acid and hexamethylenediamine is up to 80 % by weight, preferably from 30 to 75 ~ by weight, in particular from 35 to 60 % by weight.
The copolyamides may contain not only units of e-caprolactam but also units of adipic acid and hexamethyl-enediamine; in this ca~e it i~ of advantage for the proportion of units which are free of aromatic groups to be not less than 10 % by weight, preferably not les~ than 20 % by weight. The ratio of units derived from 6 -capro-lactam and from adipic acid and hexamethylenediamine istherefore not subject to any special restriction.
Preference is given to copolyamides whose compo-sition in the ternary diagram lies within the pentangle defined by the corner points X~ to X5, where the points X
to X5 are defined as follows:

X1 40 % by weight of units Al) 60 % by weight of units A3) X2 60 ~ by weight of units A1) 40 % by weight of units A3) ~3 80 % by weight of units A1) 5 % by weight of unit~ A2) 15 % by weight of units A3) X4 80 % by weight of units A1) 20~6106 - 5 - O.Z. 0050/42361 20 ~ by weight of units A2) X5 50 % by weight of units A1) 50 % by weight of units A2) In the drawing, the pentangle defined by these points i~
shown in a ternary diagram.
Of particular advantage for many applications are polyamides containing from 50 to 80, in particular from 60 to 75, % by weiqht of units derived from terephthalic acid and hexamethylenediamine (units A1) and from 20 to 50, preferably from 25 to 40, % by weight of unit~
derived fro~ e-caprolactam (units A2).
In addition to the above-described units A1) to A3), the partly aromatic copolyamides may contain further poly d de-forming monomer~ A4) of the type known from other polyamides in amounts of up to 40, preferably 10 - 30, in particular 20 - 30, % by weight.
Aromatic dicarboxylic acids A4) preferably have from 8 to 16 carbon atoms. Suitable aromatic dicarboxylic acids are ~or example isophthalic acid, substituted terephthalic and isophthalic acids such as 3-t-butylisophthalic acid, polycyclic dicarboxylic acids, eg.
4,4'- and 3,3'-biphenyldicarboxylic acid, 4,4'- and 3,3'-diphenylmethanedicarboxylic acid, 4,4'- and 3,3'-~ulfodiphenyldicarboxylic acid, 1,4- or 2,6-naphthalenedicarboxylic acid and phenoxyterephthalicacid, of which isophthalic acid i8 particularly preferred.
Further polyamide-forming monomer3 A4) can be derived from dicarboxylic acid~ of from 4 to 16 carbon atoms and aliphatic or cycloaliphatic diamines of from 4 to 16 carbon atom~ and also from aminocarboxylic acids or corresponding lactams of from 7 to 12 carbon atoms. As suitable monomer~ of these types there may be mentioned here suberic acid, azelaic acid and sebacic acid a~
repre~entatives of aliphatic dicarboxylic acids, 2~6~06 . - 6 - O.Z. 0050/42361 1,4-butanediamine, 1,5-pentanediamine, piperazine, 4,4'-diaminodicyclohexylmethane, 2,2-(4,4'-diaminodicyclo-hexyl)propaneand3,3'-dimethyl-4,4'-diaminodicyclohexyl-methane as representatives of diamine~, and capryl-lactam, enantholactam, ~-aminoundecanoic acid and lauro-lactam aR representatives of lactam~ or amino-carboxylic acids.
The following compo~itions of component (A) are particularly preferred:
A~) from 65 to 85 % by weight of units derived from terephthalic acid and hexamethylenediamine, and A4) from 15 to 35 % by weight of unit~ derived from isophthalic acid and hexamethylenediamine, or A1) from 50 to 70 % by weight of units derived from terephthalic acid and hexamethylenediamine, A3) from 10 to 20 % by weight of units derived from adipic acid and hexamethylenediamine, and A4) from 20 to 30 % by weight of units derived from i~ophthalic acid and hexamethylenediamine.
If component (A4) contains symmetrical 4,4'-3ub~tituted dicarboxylic acids (para position of the carboxyl groups), it is advisable to combine them with (A1) and (A2) or (Al) and (A3) to form ternary copolyamidesr since othexwise the copolyamide will have an exce~sively high melting point and will melt only with decompo~ition, which is not desirable.
Furthermore, tho~e partly aromatic copolyamides have proved particularly advantageous whose triamine content is less than 0.5, preferably less than 0.3, % by weight.
Partly aromatic copolyamides prepared by most existing pxocesses (cf. US-A 4 603 166) have triamine contents above 0.5 % by weight,-which leads to deteriora-tion in product quality and to problems with continuou~
production. A triamine which i8 in particular responsible for these problems is dihexamethylenetriamine, which is 2066~06 - 7 - O.Z. 0050/42361 formed from the hexamethylenediamine u~ed in the preparation.
Copolyamides having a low triamine content have lower melt viscosities than similarly composed products which have a higher triamine content, while the solution VigCoBity i8 the same. This improves not only the proces-sing properties but also the product propertie~
appreciably.
The melting points of the partly aromatic copoly-10amides lie within the range from 270C to 325C, prefer-ably from 280 to 310C, which high melting points are also associated with a high glasls transition temperature of in general more than 75C, in particular more than 85C (in the dry state).
15Binary copolyamides based on terephthalic acid, hexamethylenediamine and ~-caprolactam which contain about 70 % by weight of units derived from terephthalic acid and hexamethylenediamine have melting point~ in the 300C range and (in the dry state) a glass transition temperature of more than 110C.
Binary copolyamide~ based on terephthalic acid, adipic acid and hexamethylenediamine attain melting points of 300C or more at lower levels, about 55 % by weight, of units derived from terephthalic acid and hexamethylenediamine (HMD), although the glass transition temperature is not quite as high as with ~inary copoly-amide~ which in place of adipic acid or adipic acid/HMD
contain 6-caprolactam.
Partly aromatic copolyamides for the purposes of the present invention are those which have a degree of crystallinity > 10 %, preferably > 15 ~, and in par-ticular > 20 %.
The degree of crystallinity is a measure of the proportion of crystalline fragments in the copolyamide, and is determined by X-ray diffraction.
The preferred partly aromatic copolyamides of low triamine content can be prepared by the processes 2~66106 - 8 - O.Z. 0050/42361 described in EP-A-129 195 and EP-A-129 196.
In these processes, an aqueous solution of the monomers, ie. here the monomers which form the units A1) to A4), is heated under superatmospheric pressure to 250-300C with simultaneous evaporation of the water andformation of a prepolymer, then prepolymer and steam are continuously separated, the steam is rectified, and the entrained diamines are recycled. Finally, the prepolymer is passed into a polycondensation zone and polycondensed at 250 - 300C under a superatmospheric pressure of from 1 to 10 bar. The essential feature of the process is that the aqueou~ salt solution is heated under a superatmos-pheric pressure of from 1 to 10 bar in the course of a re~idence time of le~s than 60 seconds, and on exit from the vaporizer zone the degree of conversion is advantage-ously at least 93 % and the water content of the prepoly-mer is not more than 7 % by weight.
These short residence times substantially prevent the formation of triamines.
The aqueous solutions used generally have a monomer content of from 30 to 70 % by weight, in p~r-ticular from 40 to 65 % by weight.
The aqueous salt solution is advantageously pas~ed continuously at from 50 to 100C into a vaporizer zone, where the aqueou~ salt solution i~ heated to 250 -330C under a superatmospheric pressure of from 1 to 10, preferably from 2 to 6, bar. It will be readily under-stood that the temperature employed is above the melting point of the particular polyamide to be prepared.
As mentioned earlier, it is essential that the residence time in the vaporizer zone i9 not more than 60 seconds, preferably from 10 to 55 seconds, in par-ticular from 10 to 40 seconds.
The conversion on exit from the vaporizer zone is not less than 93 %, preferably from 95 to 98 %, and the water content i preferably within the range from 2 to 5, in particular from 1 to 3, % by weight.

206~6 - 9 - O.Z. 0050/42361 It is also advantageous to pas~ the mixture of prepolymer and steam immediately downstream of the vaporiæer zone, before the phases are separated, through a tubular mass transfer zone equipped with internal fitments. This is done under the temperature and pressure conditions employed in the vaporizer zone. The internal fitments, eg. packing such as Raschig rings, metal rings or in particular wire netting, ensure a large surface area. This ensures intimate contact between the phases, ie. prepolymer and steam, and ensures that the amount of diamine freed with steam is appreciably reduced. In general, the mass transfer zone is operated with a residence time of from 1 to 15 minutes. The mass transfer zone is advantageou~ly constructed as a tube bundle.
The two-phase mixture of steam and prepolymer emerging from the vaporizer or mas~ transfer zone is separated. Separation gen~rally takes place automatical-ly, owing to the physical differences, in a vessel the bottom part of which i9 advantageously con~tructed as a polymerisation zone. The freed vapors consist essentially of steam and diamines freed on evaporation of the water.
These vapors are passed into a column and rectified.
Suitable columns are for example packed columns, bell tray columns or qieve plate columns of from 5 to 15 theo-retical pl~tes. The column is advantageously operatedunder the same pressure conditions as the vaporizer zone.
The diamines contained in the vapor-q are separated off and returned into the vaporizer zone. It is also po~sible to pass the diamines into the downstream polymerization zone. The rectified steam obtained is withdrawn at the top of the column.
The prepolymer obtained, which accordin~ to its degree of conversion consists essentially of low molecular weight polyamide with or without residual amounts of unconverted ~alts and in general has a rela-tive viscosity of from 1.2 to 1.7, is passed into a polymerization zone. In the polymerization zone, the melt ~066~0~
- 10 - O.Z. 0050/42361 obtained is polycondensed at 250 - 330C, in particular 270 - 310C, under a ~uperatmospheric pressure of from 1 to 10 bar, in particular from 2 to 6 bar. Advantageously, the vapor3 freed here are rectified in the column to-gether with the abovementioned vapors, and preferably the polycondenaation zone is operated with a residence time of from 5 to 30 minutea. The polyamide thus obtained, which in general ha~ a relative viscosity of from 1.2 to 2.3, i8 continuou~ly removed from the conden~ation zone.
In a preferred proce~3, the polyamide thu3 obtained is passed as a liquid melt through a discharge zone with simultaneous removal of the residual water present in the melt. Suitable discharge zones are for example devolatilization extruders. The melt thus freed of water i9 then strand extruded and granulated. The granule3 obtained are advantageously condensed in solid phase by mean~ of superheated steam at a temperature below the melting point, eg. at from 170 to 240C, until the desired vigC08ity i3 obtained. Advantageously, this i8 done using the steam obtained at the top of tha column.
Following the solid pha~e postconden~ation the relative vi~cosity, measured in a 1 % by weight aolution in 96 % by weight H2SO4 at 23C, is in general within the range from 2.2 to 5.0, preferably from 2.3 to 4.5.
In a further preferred process, the polyamide melt discharged from the polycondensation zone i9 passed into a further polycondensation zone and condensed therein with continuou~ formation of new surfaces at from 285 to 310C, advantageou~ly under reduced pressure, for example at from 1 to 500 mbar, until the de~ired visco-~ity is obtained. Suitable vessels are known as finisher3.
A further proce~s, which is similar to that described above, iq deacribed in EP-A~129 196, incor-porated herein by reference.

2~661~6 ~ O.Z. OOS0/42361 As component A) it is also possible to use mixtures of different copolyamides, for which the mixing ratio is freely choosable.
As component B) the molding compositions of the present invention contain at lea~t one aroma~ic secondary amine in an amount of from 0.1 to 2, preferably from 0.5 to 1.5, in particular from 0.7 to 1, % by weight, accord-ing to the general formula I:

~ (A)m-NH-(B)~ ~ I

where m and n are each 0 or 1, A and B are each a C1-C4-alkyl- or phenyl-sub~tituted tertiary carbon atom, R1 and R2 are each hydrogen or ortho- or para-disposed Cl-C6-alkyl which may be monosubstituted, disubstituted or trisubstituted by phenyl, halogen, carboxyl or a transition metal salt of carboxyl, and R3 and R4 are each hydrogen or ortho- or para-di~po~ed methyl when m plus n is 1 or ortho- or para-disposed tertiary C3-Cg-alkyl which may be monosubstituted, disubstituted or trisubsti-tuted by phenyl when m plus n is 0 or 1.
Preferred radicals A and B are each symmetrically ~ubstituted tertiary carbon atoms, and dimethyl-substi-tuted tertiary carbon is particularly preferred. Prefer-ence i~ also given to tertiary carbons which have from 1 to 3 phenyl groups as substituents~
Preferred radical~ R1 and R2 are each para-t-butyl or tetramethyl-substituted n-butyl, although the methyl groups may preferably be replaced by from 1 to 3 phenyl groups. Preferred halogen~ are chlorine and bromine.

2~6~106 . - 12 - O.Z. 0050/42361 Preferred radicals R3 and R4 are each hydrogen in the case of m plus n = 2 or ortho- or para-dispo~ed t-butyl, which may be sub~tituted in particular by from 1 to 3 phenyl radicals, in the case of m plus n = 0 or 1.
Examples of secondary aromatic amines B) are 4,4'-bis(~,~'-tert-octyl)diphenylamine, 4,4'-bist~,~-dimethylbenzyl)diphenylamine, 4,4'-bis(~-methylbenzhydryl)diphenylamine, 4-(1,1,3,3-tetramethylbutyl)-4'-triphenylmethyldiphenyl-amine 4,4'-bis(~,~-p-trimethylbenzyl)diphenylamine 2,4,4'-tris(~,~-dimethylbenzyl)diphenylamine 2,2'-dibromo-4,4~-bis(~,~-dimethylbenzyl)diphenylamine 4,4'-bis(~,~-dimethylbenzyl)-2-carboxydiphenylamine-nickel-4,4'-bis(~,~-dimethylbenzyl)diphenylamine 2-sec-butyl-4,4'-biY(~,~-dimethylbenzyl)diphenylamine 4,4'-bis(~,~-dimethylbenzyl)-2-(~-methylheptyl)diphenyl-amlne 2-(~-methylpentyl)-4,4'-ditrityldiphenylamine 4-~,~-dimethylbenzyl-4~-isopropoxydiphenylamine 2-(~-methylheptyl)-4~ -dimethylbenzyl)diphenylamine 2-(~-methylpentyl)-4'-trityldiphenylamine 4,4'-bis(tert-butyl)diphenylamine and also:

~3~-0-NH~

~;C~ CH
>-I-NH~

2~6106 - 13 - O.z. 0050/42361 C~3 C ~ N ~ CH3 ~ Cl Cl ~

CH3 1 ~ N

/ ~ IH
CH3 ~

NH

CH3 ~

CH3-C ~ N ~ C-CH3 CH3-C-CH2-1 ~ NH ~ O_CH2_C_CH3 - 14 - O.Z. 0050/42361 CH3--C~ NH~ --0--CH3 -¢-NH~

CH3~1--NH--I~CH3 CH3--¢--1~>---NH----~

~3--l--~--NH--~> ~ 4 ~3 ~

~--NH--I~

They are prepared as described in 8E-A-67/0500120 and CA-A-963594.
Preferred secondary aromatic amine~ are diphenyl-amine and derivatives thereof, which are commerciallyavailable as Naugard (from Uniroyal).
As component C) tho molding compositions of the present invention contain from 100 to 2000, preferably 2~66~ 0~

- - 15 - O.Z. 0050/42361 200-500, in particular 200-400, ppm of at least one phosphorus-containing inorganic acid or a derivative thereof, ba~ed on the total amount of components A) and B) in the molding compositions.
Preferred acids are hypophosphorous acid, phos-phorous acid and phosphoric acid and also salts thereof with alkali metals, of which sodium and potassium are particularly preferred. Preferred mixtures are in parti-cular hypophosphorous and phosphorous acid or their alkali metal salts in a ratio of from 3 : 1 to 1 : 3.
Organic derivative~ of these acids are preferably to be understood as meaning ester derivatives of the above-mentioned acids.
As component D) the molding compositions of the present invention may contain from 0 to 59.9, in particular from 5 to 50, particularly preferably from 10 to 35, % by weight of a fibrous or particulate filler or of a mixture of such fillers.
Examples of fibrous fillers are glass fibers, carbon fibers, aramid fibers, potassium titanate fibers and fibrous silicates such as wollastonite.
If glass fiber~ and fillers based on silicate are used, they may have been dressed with a size and a coupling agent for better compatibility with the poly-amide.
In general, the glass fibers used have a diameterwithin the range from 6 to 20 ~m. They can be incor-porated not only in the form of short fibers but al o in the form of continuou~ strands or rovings. In the finished injection molding, the average length of the glass fibers is preferably within the range from 0.08 to 5 mm.
Suitable particulate fillers are for example glas~ balls, particulate wollastonite, quartz powder, boron nitride, kaolin, calcium carbonate, magne3ium carbonate (chalk) and titanium dioxide, of which wollas-tonite, titanium dioxide and kaolin are in general . - 16 - O.Z. 0050/42361 preferred.
As component E) the thermoplastic molding compo-sition~ according to the present invention contain from 0 to 30, preferably from 5 to 20, % by weight, based on the sum total of component~ A) to E), of an ela~tomeric polymer.
In general, thi~ will be a copolymer which i~
preferably compo~ed of at least two of the following monomers as main components: ethylene, propylene, isobu-tene, isoprene, chloroprene, vinyl acetate, styrene,acrylonitrile and acrylic and methacrylic ester~ having from 1 to 18 carbon atom~ in the alcohol component.
Rubbers of this kind are de~cribed for example in Houben-Weyl, Methoden der organischen Chemie, vol. 14/1 (Thieme-Verlag, Stuttgart, 1961), pages 392-406, and in the monograph by C.B. Bucknall, Toughened Pla3tics (Applied Science Publishers, London, 1977).
Preferred types of these elastomers are the ethylene-propylene monomer (EPM) and ethylene-propylene-diene monomer (EPDM) rubber~, which preferably have an ethylene unit to propylene unit ratio within the range from 40:60 to 90:10.
The Mooney viscosities (MLI+4/100C) of such uncro~linked EPM or EPDM rubbers (gel contents in general below 1 % by weight) are preferably within the range from 25 to 100, in particular from 35 to 90 (meas-ured with the large rotor after 4 minutes at 100C in accordance with German Standard Specification DIN 53 523).
EPM rubbers in general have virtually no double bonds left, while EPDM rubber~ can have from 1 to 20 double bonds/100 carbon atoms.
. As diene monomers for EPDM rubbers there may be mentioned for example conjugated dienes such as isoprene, nonconjugated dienes of from 5 to 25 carbon atom~ such as 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 2,5-dimethyl-1,5-hexadiene and 1,4-octadiene, cyclic dienes 2~6~106 - 17 - O. Z . 005~/42361 such as cyclopentadiene, cyclohexadienes, cyclooctadienes and dicyclopentadiene and also alkenylnorbornenes such as 5-ethylidene-2-norbornene, 5-butylidene-2-norbornene, 2-methallyl-5-norbornene, 2-isopropenyl-5-norbornene and tricyclodiene such as 3-methyltricyclo [ 5 . 2 . 1. 0 . 2 . 6 ] -3, 8-decadiene or mixtures thereof . Pref erence is given to 1, 5-hexadiene, 5-ethylidenenorbornene and dicyclopentadiene. The diene content of the EPDM rubbers i9 preferably from 0.5 to 50, in particular from 1 to 8, % by weight, based on the total weight of the rubber.
EPM and EPDM rubbers can preferably also be grafted with reactive carboxylic acids or derivatives thereof. These include for example acrylic acid, meth-acrylic acid and derivatives thereof and also maleic anhydride.
A further group of preferred rubbers are copoly-mers of ethylene with acrylic acid and/or methacrylic acid and/or the esters of these acids. In addition, the rubbers may contain dicarboxylic acids such as maleic acid and fumaric acid or derivatives thereof, such as esters and anhydrides, and/or epoxy-containing monomers.
These dicarboxylic acid derivatives and epoxy-containing monomerc are pref erably incorporated in the rubber by adding dicarboxylic acid- or epoxy-containing monomers of the general formula II or III or IV or V to the monomer mixture 2~6~1~6 - 18 - O.Z. 0050/4236 R~C(COOR2~=C(COOR3)R4 Il \C C~
I I I
CO CO
`O' CHR7=CH--(CH2) ~(CHR6) --CH--CHR5 IV
m n CH2=CR9--COO--(--CH2)--CH--CHR8 V
n \o/

where Rl to R9 are each hydrogen or alkyl of from 1 to 6 carbon atoms, m is an integer from 0 to 20, n is an integer from 0 to 10 and p is an integer from 0 to 5.
Preferably, each of Rl-R7 is hydrogen, m is 0 or 1, and n is 1. The corresponding compounds are maleic acid, fumaric acid, maleic anhydride, allyl glycidyl ether and vinyl glycidyl ether.
Preferred compounds of the formulae II, III and V
are maleic acid, maleic anhydride and epoxy-containing esters of acrylic acid and/or methacrylic acid, of which glycidyl acrylate, glycidyl methacrylate and the esters with tertiary alcohols, such as t-butyl acrylate, are particularly preferred. It i3 true that the latter have no free carboxyl groups, but their behavior is similar to that of the free acids and therefore they are referred to as monomers having latent carboxyl groups.
The ethylene content of the copolymers i3 in general-within the range from 50 to 98 % by weight, and the proportion of methacrylic esters is within the range from 2 to 50 % by weight. Advantageously, the copoly~ers consist of from 50 to 98 ~ by weight of ethylene, from 0.1 to 20 ~ by weight of epoxy-containing monomers and/or methacrylic acid and/or acid anhydride group-containing monomers and also methacrylic ester~ as remainder.

2~6~06 - 19 - O.Z. 0050/42361 Particular preference is given to copolymers of from 50 to 98.9, in particular from 60 to 95, % by weight of ethylene, from 0.1 to 40, in particular from 0.3 to 20, % by weight of glycidyl acrylate and/or glycidyl methacrylate, acrylic acid and/or maleic anhydride, and from 1 to 45, in particular from 10 to 35, % by weight of n-butyl acrylate and/or 2-ethylhexyl acrylate.
Further preferred esters of acrylic and/or methacrylic acid are the me~hyl, ethyl, propyl and i- or t-butyl esters.
In addition it is also pos~ible to use vinyl esters and vinyl ether~ as comonomer~.
The above-described ethylene copolymer~ can be prepared in a conventional manner, preferably by random copolymerization under high pressure at elevated temperature. Appropriate methods are common knowledge.
The melt index of the ethylene copolymers is in general within the range from 1 to 80 g/10 min (measured at 190C under a load of 2.16 kg).
Preferred elastomers E) are emulsion polymers whose preparation i8 described for example in Houben-Weyl, Methoden der organischen Chemie, volume XII. I
(1961), and also in Blackley~s monograph, Emulsion Polymerization. The emulsifiers and catalysts used are known per se.
In principle, it is possible to use elastomers which have a homogeneous structure or else elastomer~
which have a shell ~tructure. The shell-like ~tructure is determined by the order of addition of the individual monomers; the order of addition also has a bearing on the morphology of the polymers.
Merely representative examples of monomers for preparing the rubber part of the elastomer~ are acryl-ates, eg. n-butyl acrylate or 2-ethylhexyl acrylate, the 2~66~06 - 20 - O.Z. 0050/42361 corresponding methacrylates and isoprene and also mix-tures thereof. These monomers can be copolymerized with further monomer~ such as Ytyrene, acrylonitrile, vinyl ethers and further acrylates or methacrylates such as methyl methacrylate, methyl acrylate, ethyl acrylate and propyl acrylate.
The soft or rubber phase (having a glass transi-tion temperature of below 0C) of the elastomers can represent the core, the outer sheath or an interm~diate shell (in the case of elastomers having more than two shells); in the case of multishell elastomer it is also possible for more than one shell to be made of a rubber phase.
If ln addition to the rubber phase one or more hard component~ (having glass transition temperatures of more than 20C) are involved in the formation of the elastomer, they are in general prepared by polymerization of styrene, acrylonitrile, methacrylo-nitrile, ~-methylstyrene, p-methylstyrene, acrylic esters and methacrylic ester~ such as methyl acrylate, ethyl acrylate and methyl methacrylate as principal monomers.
Again, here too, minor amounts of further comonomers can be used.
In some cases it will be advantageous to use emulsion polymers which have reactive groups at the surface. Such groups are for example epoxy, carboxyl, latent carboxyl, amino or amide groups and also func-tional groups which can be introduced by using monomers of the general formula 7, l2 CH2=C--X--N--I_R3 where the substituents can have the following meanings:
Rl is hydrogen or C1-C4-alkyl, R2 is hydrogen, Cl-Cg-alkyl or aryl, in particular 2~6~1~6 - 21 - O.Z. 0050/42361 phenyl, R3 is hydrogen, C1-C10-alkyl, C6-C12-aryl or -oR4, R4 is C1-C8-alkyl or C5-C12-aryl, which may each be sub~tituted by O- or N-containing groups, X is a chemical bond, Cl-C~0-alkylene, C6-C12-arylene or --c--Y

Y is O-Z- or NH-Z and Z i~ C1-C10-alkylene or C8-C12-arylene.
It is also po~sible to use the graft monomers described in EP-A-208 187 for introducing reactive groups at the surface.
Further examples are acrylamide, methacrylamide and subatituted ester~ of acrylic acid or methacrylic acid such as (N-t-butylamino)ethyl methacrylate, (N,N-dimethylamino)ethyl acrylate, (N,N-dLmethylamlno)methyl acrylate and (N,N-diethylamino)ethyl acrylate.
-Furthermore, the particles of the rubber phase may also be crosslinked. Crosslinking monomers are for example divinylbenzene, diallyl phthalate and dihydrodi-cyclopentadienyl acrylate and also the compounds de-scribed in EP-A 50 265.
Furthermore, it is also possible to use graft-linking monomers, ie. monomers having two or more poly-merizable double bonds which react at different rates during the polymerization. Preference is given to tho~e compounds in which at least one reactive group polymer-izes at substantially the same rate aa the other mono-mers, while the other reactive group or groups polymer-izes or polymeriæe for example at a distinctly slower rate. The different polymerization rates introduce a certain proportion of unsaturated double bonds into the rubber. If such a rubber is subsequently grafted with a further phase, the double bonds present in the rubber react at leaRt partly with the graft monomers to form 2~6106 . - 22 - O.Z. 0050/42361 chemical bonds, so that the grafted-on phase ends up being linked at least to some extent to the grafting base via chemical bonds.
Examples of such graft-linking monomers are allyl-containing monomers, in particular allyl esters of ethylenically unsaturated carboxylic acids such as allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, diallyl itaconate or the corresponding mono-allyl compounds of these dicarboxylic acids. There are many other suitable graft-linking monomers; for details reference should be made for example to US-A 4 148 846.
In general, the proportion of these crosslinking monomers in component E) i~ up to 5 ~ by weight, prefer-ably not more than 3 % by weight, based on E).
In what follows, some preferred emulsion polymers are listed. The firQt group to be mentioned here are graft polymers having a core and at least one outer shell which have the following structure:

2066~06 - 23 - O.Z. 0050/42361 Type Monomers for the core Monomers for the ~heath -A n-butyl acrylate, styrene,acrylonitrile, ethylhexyl acrylate methyl methacrylate or mixture~ thereof B as for A but with the a~ for A
use of crosslinkers C a~ for A or B n-butyl acrylate, ethyl acrylate, methyl acrylate, isoprene, ethylhexyl acrylate D as for A or B as for A or C but with the u8e of monomers having reactive groups a~ described herein E styrene, acrylo- first ~heath made of nitrile, methyl monomers as described methacrylate or under A and B for the mixtures thereof core second sheath as de~cribed under A or C
for the sheath In~tead of graft polymers having a multishell structure it is also possible to u3e homogeneous, ie.
single-shell, elastomers formet of isoprene and n-butyl acrylate or copolymer~ thereof. These product too can be prepared using crosslinking monomers or monomers having reactive groups.
Examples of preferred emul~ion polymers are n-butyl acrylate/(meth)acrylic acid copolymer , n-butyl acrylate/glycidyl acrylate or n-butyl acrylate/glycidyl methacrylate copolymers, graft polymers having an inner 206610~
- 24 - O.Z. 0050/42361 core of n-butyl acrylate and an outer sheath of the aforementioned copolymers and copolymers of ethylene with comonomers which provide reactive groups.
The above-described elastomers E) can also be prepared by other customary methods, for example by su~pension polymerization.
It is of course also possible to use mixtures of the aforementioned types of rubber.
Preference is given to using rubbers which contain no butadiene.
In addition to the essential components A) to C) and the optional components D) and E), the molding compositions of the present invention may contain custo-mary additives and processing aids. The proportion thereof i8 in general up to 20, preferably up to 10, 96 by weight, ba~ed on the total weight of components A) to E).
Customary additives are for example W stabil-izers, lubricants, demolding agents, colorants, dyes and pigments and plasticizers and also flame retardants.
Examples of W ~tabilizers are various substi-tuted resorcinols" salicylates, benzotriazoles and benzophenones, which in general are used in amounts of up to 2.0 % by weight.
Lubricants and demolding agents, which in general are added to the thermoplastic composition in amounts of up to 1 % by weight, are stearic acids, stearyl alcohol, alkyl stearates, N-alkylstearamides and also esters of pentaerythritol with long-chain fatty acids.
Flame xetardants can in general be present in the molding composition in amounts of up to 20 % by weight.
It is possible to use here any known flameproofing additives for polyamide, but preference is given to elemental red or black phosphorus.
The molding composition~ of the present invention can be prepared in a conventional manner by mixing the starting components in customary mixing apparatuse ~uch as screw extruders, Brabender mills or Banbury mills and - 25 - O.Z. 0050/42361 then extruding the mixture. After extrusion, the extru-date i8 cooled and comminuted. The mixing temperatures are in general within the range from 260 to 350C, preferably from 280 to 340C.
The thermoplastic molding compositions of the present invention score over thermoplastic molding compo~itions based on aliphatic or amorphous polyamides in particular on account of high and prolonged stability at elevated application and processing temperatures. In particular the impact toughness and light natural color of these stabilized copolyamides remain stable at high temperatures over prolonged periodsO Compared with stabilized articles shaped from aliphatic polyamides, the shaped articles formed from the molding composition~ of the present invention are notable for the significantly improved long-term effectiveness of the stabilizing effect.
Owing to this property spectrum, the molding compo~itions of the present invention are suitable in particular for manufacturing article~ which are to be subjected to high sustained-use temperatures. This ic true in particular of applications in the automotive vehicle sector, since engine compartments, built com-pactly and with increased soundproofing insulation, require higher use temperatures of the polyamide~ used therein.
EXANPLES
Component A/l A partly aromatic copolyamide composed of Al) 70 % by weight of units derived from terephthalic acid and hexamethylenediamine, and A2) 30 % by weight of unit~ derived from 6-caprolactam.
The viscosity number as defined in ISO 307 was 141 ml/g (measured in a 0.5 % strength by weight solution in 96 % strength sulfuric acid at 25C).
Melting point: 298C
Glass tran~ition temperature: 113C

2 ~ 6 ~
- - 26 - O.Z. 0050/42361 Crystallinity: 26 %
Component A/2 A partly aromatic copolyamide composed of:
A1) 60 % by weight of unit~ derived from terephthalic S acid and hexamethylenediamine, and A2) 40 % by weight of units derived from ~-caprolactam.
Viscosity number as defined in ISO 307 : 137 ml/g Melting point : 281C
Gla~s tran~ition temperature : 100C
Crystallinity : 13 %
Component A/3 A partly aromatic copolyamide compo-~ed of A1) 50 % by weight of units derived from terephthalic acid and hexamethylenediamine, and A3) 50 % by weight of units derived from adipic acid and hexamethylenediamine.
Visco~ity number as defined in ISO 307 : 142 ml/g Melting point : 292C
Glas~ tranqition temperature : 91C
Crystallinity : 28 %
Component A/Comparison 1 Polyhexamethyleneadipamide Vi~cosity number a~ defined in ISO 307 : 145 ml/g Melting point : 2629C
25 Glass transition temperature : 55C
Crystallinity : 43 %
Component B/l 4,4'-Bi~ dimethylbenzyl)diphenylamine (Naugard 445, from Uniroyal) Component B/2 Reaction product of diphenylamine and acetone (Naugard A, from Uniroyal) 20661~6 - 27 - O.Z. 0~50/42361 Component B/Comparison 1 A stabilizer based on sterically hindered phenols (Irganox~ 1098, from Ciba-Geigy) H~CH 2--CH ~--C--N--( CH 2 ) 6 - N - c - cH 2--CH 2~0H

Component C/l Na~2PO2 x 5 ~2O (commercial product from E. Merck) Component C/2 NaH2PO3 x 12 H2O (commercial product from E. Merck) Component C~3 NaH2PO4 x 1 H2O (commercial product from E. Merck) Component C/Comparison 1 A mixture of copper iodide and potas~ium iodide in a mixing ratio of 1 : 10.
Component D
Glas~ fiber~ in the form of chopped fibers having an average diameter of 10 ~m and a length of 4.5 mm (Gevetex~ P 537 from Vetrotex) Preparation of molding compositions Components A) to C) and, if used, D) were com-pounded on a twin-screw extruder (ZS~ 30, Werner &
Pfleiderer) at 320C with 250 rpm and a throughput of 20 kg/h, extruded in ~trand form, cooled down in a waterbath and granulated. The granules were dried and injection molded into test specimens at 320C.
The stability wa~ determined by storing the test specimens in air at 140 or 160C and subsequently deter-mining the notched impact strength a~l as defined in DIN 53 753 (at 23C, dry) as a function of the length of storage. The~e curve~ were used to determine the number of days (of storage) after which the notched impact strength drops to below 20 kJ/m2 (residual toughness), as a measure of the effectiveness of the stabilizer system.
In the case of the glas~ fiber reinforced molding compo-sitions, the impact toughness was measured by the method 2066~6 . - 28 - O.Z. 0050/42361 of Charpy ~DIN 53 453) as a function of the storage period until the limit of 20 kJ/m2 was reached.
The compositions of the molding material~ and the resultQ of the measurements are discernible from the tables.

2a~o~
- 29 - O.Z. 0050/42361 U U
o. P.
oo Ln U~
+ +
U ~ ~ C

~U~U~
o ~ UUU
N ~ Ei Ei ,C D~
.,1 ~ ~ ~ooo uuuu~uuuu e~uu uooo 3 Ei Ei E3 ii E3 5 E3 Ei Ei Ei E3 Ei .a ~P.O.~P.P. Q.~ P.+ + +
dP OOOOOOOOO OOO OOOO
U~ In U7 0 0 U~ In I O O O I In u~

.
.~.

~; c mmmmmmmmmm m _, .......... .
o oOoooooo~ O
o o ~q ~ C
~ c ~ ~
o o u~ ~

8 8 ~
U U ~ ~ ~ ~ ~ ~ ~
.
o ~ o o o c~ a~ o o o n o o o o a~ o o o ,, l . ...

, " C ~ ~ ~, C

2~661~6 - 30 - O.Z. 0050/4236 o S
.,1 d~
o U U U U U U

oP , o o o o o o -.
.,~ h " ~ uuumm~m ", ~ mmmr~mr~
1 0 0 _1 0 E~ W
o e O oq .,1 ~ ~n ~ C
.,., ~ a.
o o U
o~ o~
U U

C
h ~

X a~ O _I N t~l ~ Lr) O
h U
o a~
W
__ ~ .a - 31 - .Z. 0o5o/42326o 6 6~ 0 Result~ of measurements Example Days (T = 140C) Days (T - 160C) Residual akl = 20 kJ/m2akl = 20 kJ/m2 loa, 8 3 11~ 4 12a) 4 13~) 3 14~ 2 ~1 15a) 35 9 16~ 37 10 17A) 38 9 18~) 40 8 19~) 3 20~) 4 21~ 3 a) for comparison b) decomposition :~
.

2 0 ~
. - 32 - O.Z. 0050/42361 The re~ults of the measurements show that, compared with other polyamides, a significantly better long-term tability at elevated temperatures is achieved for the same amount of stabilizer. The measurements also show that comparative stabilizers which are highly suitable for aliphatic polyamides do not provide effec-tive stabilization for partly aromatic copolyamides.

Claims

1. A thermoplastic molding composition containing A) 40-99.9 % by weight of a partly aromatic and partly crystalline copolyamide having a triamine content of less than 0.5 % by weight composed of (A1) 20-90 % by weight of units derived from tereph-thalic acid and hexamethylenediamine, (A2) 0-50 % by weight of units derived from ?-caprolactam, (A3) 0-80 % by weight of units derived from adipic acid and hexamethylenediamine, (A4) 0-40 % by weight of further polyamide-forming monomers, the proportion of component (A2) or (A3) or (A4) or a mixture thereof being not less than 10 % by weight, B) 0.1-2 % by weight of at least one aromatic secondary amine, and C) 100-2000 ppm of at lea t one phosphorus-containing inorganic acid or a derivative thereof, the proportion of component C) being based on the total amount of components A) and B), and also D) 0-59.9 % by weight of a fibrous or particulate filler or a mixture thereof, E) 0-30 % by weight of an elastomeric polymer.

2. A thermoplastic molding composition as claimed in claim 1, containing as component B) an aromatic secondary amine of the general formula I
I

where m and n are each 0 or 1, A and B are each a C1-C4-alkyl- or phenyl-substituted tertiary carbon atom, -34- O.Z. 0050/42361 R1 and R2 are each hydrogen or ortho- or para-disposed C1-C6-alkyl which may be monosubstituted, disubstituted or trisubstituted by phenyl, halogen, carboxyl or a transition metal salt of carboxyl, and R3 and R4 are each hydrogen or ortho- or para-disposed methyl when m plu8 n is 1 or ortho- or para-disposed tertiary C3-C9-alkyl which may be monosubstituted, disubstituted or trisubsti-tuted by phenyl when m plus n is 0 or 1.

3. A thermoplastic molding composition as claimed in claim 1, wherein component C) comprises hypophosphorous acid, phosphorous acid, phosphoric acid, an alkali metal salt thereof or a mixture thereof.

4. A thermoplastic molding composition as claimed in claim 1, wherein the partly aromatic copolyamide A) contains A1) 50-80 % by weight of units derived from terephthalic acid and hexamethylenediamine, and A2) 20-50 % by weight of units derived from ?-capro-lactam.

5. A thermoplastic molding composition as claimed in claim 1, wherein the partly aromatic copolyamide A) contains A1) 25-70 % by weight of units derived from terephthalic acid and hexamethylenediamine, and A3) 30-75 % by weight of units derived from adipic acid and hexamethylenediamine.

6. A thermoplastic molding composition as claimed in claim 1, wherein the partly aromatic copolyzmide A) contains A1) 65-85 % by weight of units derived from terephthalic acid and hexamethylenediamine, and A4) 15-35 % by weight of units derived from isophthalic acid and hexamethylenediamine.

7. A thermoplastic molding composition as claimed in claim 1, wherein the partly aromatic copolyamide A) - 35 - O.Z. 0050/42361 contains A1) 50-70 % by weight of units derived from terephthalic acid and hexamethylenediamine, A3) 10-20 % by weight of units derived from adipic acid and hexamethylenediamine, and A4) 20-30 % by weight of units derived from isophthalic acid and hexamethylenediamine.

8. A thermoplastic molding composition as claimed in claim 1, wherein component A) has a melting point of from 270°C to 325°C.

9. A shaped article obtainable from a partly aromatic copolyamide as set forth in claim 1.