GB2197332A - Transparent copolyamides and their use for light guide claddings and moulded bodies - Google Patents

Description

1 GB2197332A 1

SPECIFICATION

Transparent copolyamides and their use for light guide claddings and moulded bodies The invention relates to new transparent copolyamides based on alkyl derivatives of bis(4- 5 aminocyclohexyl) methane alone or in admixture with other diamines.

Polyamides and copolyamides prepared by the use of 3-aminometyl-3,5,5'trimethylcyclohexy- lamine (isophorone diamine, IPD), 4,4-diaminodicylcohexyl or of diamines of the bis(4-aminocyclo hexyl)alkane-type, which can be substituted by methyl groups on the cyclohexyl substiluents, are known.

The polyamides described in GB-A-0619707 and in US-A-2494563, derived from 4,4'-diami nodicyclohexyl or from diamines of the bis(4-aminocyclohexyl)methane-type and dicarboxylic acids such as adipic acid or sebacic acid are transparent if, in their preparation, the diamines are introduced as liquid isomeric mixtures at 25'C. The workability and certain properties such as the transparence stability and the hydrolysis-resistance with respect to boiling water, the tear 15 resistance in organic solvents of these transparent polyamides, however, leave something to be desired.

The transparent polyamide described in US-A-2696482, derived from isomeric mixtures of 4,4-diaminodicylohexylmethane which are liquid at 25C and from isophthalic acid has good resistance to hot water. However, in order to conduct the polycondensation satisfactorily, the 20 diphenyl ester of isophthalic acid must be used as a starting material or phenol must be added to the polycondensation mixture as solvent or plasticiser. On account of the high softening temperature and the high melt viscosity of these transparent polyamides, which have a maximum water uptake of 7.75%, working temperatures of about 330'C are necessary.

The transparent polyamide described in US-A-2516585, derived from bis(4amino-3-methylcy- 25 cl ohexyl) methane and terephthalic acid has similar disadvantages.

The transparent copolyamides described in US-A-3847877, derived from 4,4'diaminodicylo hexylmethane, terephthalic acid and/or isophthalic acid, and caprolactam, have a comparably high capacity for water absorption, and tend to cloudiness after treatment for a few days with boiling water. Further, they contain a proportion of unreacted monomeric caprolactarn which reduces or 30 prevents their use in several areas.

This last feature applies also to the copolyamides described in DE-A1595354, derived from 2,2-bis(4-aminocyclohexyl)propane, dicarboxylic acids with more than 20% w/w caprolactarn and/or a further conventional polyamide-forming components, e.g. hexamethylenediarpmonium adipate, which are soluble in methanol.

In so far as the transparent polyamides described in DE-A-1595354 are prepared from 2,2 bis(4-aminocyclohexyl) propane and a dicarboxylic acid such as adipic acid alone, they have better solvent resistance, but have poor workability on account of their high softening point. It is not possible to prepare from them injection mouldings free from strain.

The transparent copolpmides described in US-A-3597400, derived from 4,4'diaminodicylo- 40 hexylmethane, hexamethylenediamine, terephthalic acid and isophthalic acid, have a high water absorption capacity. As a result, on storing these transparent copolyamides in water, their softening points are reduced to 50-60'C.

The transparent copolyamides described in US-A-3842045 which are polycondensation pro ducts of 4,4'-diaminodicyclohexylmethane which is only 40-54% in the trans-trans configuration, 45 and a mixture of 50-70 mol% 1,10-decanedicarboxylic acid and 30-50 mol % suberic acid or azelaic acid, contain neither aromatic dicarboxylic acid nor an additional polyamide-forming com ponent. This is also the case for the transparent copolyamides derived from 2-2-bis(4-aminocy clohexyl) propane and/or its methyl derivatives and from dicarboxylic acid mixtures which com prise 20-65 mol % adipic acid and 35-80 mol % suberic acid, azelaic acid, sebacic acid and/or 50 1,10-decanedicarboxylic acid, according to the teaching of US-A-3840501.

CH-A-0449257 also relates to transparent polyamides derived from 1,10decanedicarboxylic acid and diamines of the dicycane type, including bis(4-amino-3- methylcyclohexyl) methane or 2,2 bis(4-aminocyclohexyl)propane with similar structure.

DE-A-2405985 discloses f la me-repel lent, thermoplastic moulding materials containing red phos- 55 phorus and also a transparent polyamide or mixtures of two or more transparent polyamides.

Among the transparent polyamides, those which are named include those derived from 35 mol - % 4,4'-diaminodicyclohexylmethane or 2,2-bis(4-aminocyclohexyl) propane, 35 mol % isophthalic acid and 30 mol % co-aminolauric acid (or its corresponding lactam) or a stoichiometric mixture of dodecamethylenediamine and 1,10-decanedicarboxylic acid. The monomer mixtures used for 60 the preparation of these polyamides comprise 33 or 31.5% w/w (0- aminolauric acid or the stoichiometric mixture of dodecamethylenediamine and 1,10-decane- dicarboxylic acid, respec tively.

DE-A-2936759 describes transparent copolyamides having a high glass transition point, into which at least 30% w/w of a (o-aminocarboxylic acid having at least 11 C atoms are introduced 65 2 GB2197332A 2 in order to reduce the high processing viscosity, and which contains a considerable amount of isophoronediamine in addition to a diamine of the dicycane type. However, this leads to brittleness and discolouration of the copolyamides.

EP-A-0012931 describes transparent copolyamides which are derived from, inter alia, adipic acid, hexamethylenediamine and, as further diamine component, a mixture of bis(4-aminocyclohexyi)methane. In consequence, the hot water resistance is insufficient.

DE-A-2642244 describes transparent copolyamides derived from waminocarboxylic acid, isophthalic acid and a methyl derivative of bis(4aminocyclohexyi) methane, which exhibit unsatisfactory heat moulding resistance, strain crack corrosion, toughness, transparence stability and hydrolysis-resistance in boiling water, and have the disadvantage of a relatively high working viscosity.

US-A-4293687 describes the general class of bis(4-aminocyclohexyi)methanetype diamines, and their preparation. The disclosure of this patent specification is directed towards certain crystalline linear polyamides and not to amorphous copolyamides.

The preparation of the 3,5-diethyl homologue of bis(4-a m inocyclohexyl) methane, described in 15 GB-A-21 70209, is relatively expensive. Owing to the low reactivity of these diamine components, high temperatures and long reaction times are necessary for the preparation of the copolyamides described therein, in order to obtain satisfactory viscosity.

The invention has the object of producing easily processable copolyamides having high tran- sparency and very good properties in use, in particular for use as a lightwave conductor cladding 20 and for injection moulding to moulded bodies, which no longer have the disadvantages, de scribed above, of the known copolyamides. Surprisingly, it has been found that an asymmetri cally-substituted bis(4-aminocyclohexyl) methane is of especial value, and which has reactivity dependent on its isomeric form.

According to the invention, new transparent copolyamides are obtainable by polycondensation 25 of alkyl derivatives of bis(4-aminocyclohexyi)methane and, optionally, further diamines, with iso phthalic acid and, optionally, terephthalic acid or aliphatic dicarboxylic acids and further polyam ide-forming components having 6 or more carbon atoms, characterised in that a selected mixture of isomers of bis(4-amino-3-methyi-5-ethylcyclohexyl)methane, which preferably contains tran- s/trans and/or cis/trans isomers, is used as the alkyl derivative of bis(4-aminocyclohexyl)meth ane.

According to a specific embodiment, the transparent copolyamides according to the invention are prepared by polyconclensation of a) bi s (4-a min o-3-methy]-5-ethyleyclohexyi) methane as a selected mixture of isomers, which preferably contains trans/trans and/or cis/trans isomers, alone or in admixture with other diam- 35 ines, with b) the approximately stoichiometric amount, with respect to components a), of isophthalic acid, of which 0-50% (mol or by weight) can be replaced by terephthalic acid or its homologues or 5 to 98% w/w by further aliphatic dicarboxylic acids, and c) 20 to 60% by weight of the sum of a), b) and c), of one or more polyamide-forming components such as Cl) a (i)-aminocarboxylic acid or its lactam having more than 8 C atoms and/or C2, a salt or 1: 1 stoichiometric mixture of a dicarboxylic acid, in particular a a,o) polymethylenedicarboxylic acid and an aliphatic diamine, in particular a a,o)-polymethylenediamine, wherein the condition applies that there is an average number of at least 7 methylene groups in c) per amide group or per pair of amide-forming groups, and the mininum number of methylene 45 groups between the amide-forming groups is 6, and wherein, further, when part of the iso phthalic acid is replaced by an aliphatic dicarboxylic acid, the sum of the weights of the aliphatic dicarboxylic acids, and the additive c) must lie in the range of 20-60% by weight of the sum of a), b) a n d c).

Highly transparent copolyamides are thus obtained on the addition of the polyamide-forming 50 components according to c), and which have good processability, very good mechanical proper ties and excellent transparence stability and hydrolysis-resistance in boiling water, as well as a good tensile strength with respect to organic solvents, and remain transparent even in blends with other polyamides, especially with nylon 11 and 12.

Nowhere in the available state of the art is there any indication of the use of the steric 55 influences on the reactivity of the amino groups of the bis (4- aminocyclohexyl) methane derivative which is introduced, not only in terms of the nature and position of the alkyl substituents, but also in connection with the isometry of the cyclohexyls. The selected isomeric mixture of the bis(4-amino-3-methyl-5-ethylcyclohexyl)methane according to a) therefore means a selected reac- tive mixture which contains only low amounts, preferably below 20%, and most especially less 60 than 10% w/w, of cis/cis isomers. The proportion of the trans/trans and cis/trans isomers is then at least 80%, but preferably more than 90% w/w. It is apparently important that the 3 methyl and 5-ethyl groups are each in the immediate vicinity of the amino group.

The further diamine components which, if desired, are used in addition to the alkyl derivative of bis(4-aminocyclohexyl)methane according to the invention, preferably comprise bis(4-amino-3- 65 3 GB2197332A methylcyclohexyl) methane, bis(4-amino-3,5-diethylcylohexyi) methane, bis(4-amino-3-methyl-5-isopropylcyclohexyi)methane, bis(4-a minocyclohexyl) methane, 2,2-bis(4-aminocyclohexyi)propane or further substituted diamines of the bicyclohexylalkane-type, 1,3bis(aminomethyi)cyclohexane, 3aminomethyi-3,5,5-trimethylcyclohexylamine, 2,4,4-(2,2,4)-trimethyihexamethylenediamine, hexam- ethylenediamine, methyl pentamethylenediamine, 3(4),8(9)bisaminomethyitricylo[5,2,1,011,6]decane or 2,6-bis(aminometyi) norbornane-m-xylylenedia mine.

The bis(4-amino-3-methyi-5-ethylcyclohexyi)methane can be mixed with such diamines in the mol ratio 0.9:0A to 0.1:0.9. However, for such additional diamines, it is not necessary to make any restrictions with respect to the existing isomers.

For use as the acid components according to b), isophthalic acid alone or mixtures of isophthalic acid and terephthalic acid which contain up to 50% (mol or weight) terephthalicacid and/ substituted isophthalic acids are suitable. 5 to 98% of the isophthalic acid can be replaced by aliphatic dicarboxylic acids. Such dicarboxylic acids are advantageously those having more than 6 C atoms, especially suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, undecanedicarboxylic, dodecanecarboxylic acid, tridecanedicarboxylic acid, and their side chain- 15 substituted homologues.

Polyamide-forming components according to Cl include laurolactarn or o)aminolauric acid and (o-aminoundecanoic acid or a mixture thereof. Those according to C2 include salts of a,co diaminoalkanes such as 1,6-diaminohexane, 1,8-diamnooctane, 1,9- diaminononane, 1,10-diamino decane, 1,12-diaminododecane, 1,13-diaminotridecane or 2,2-4- or 2,4,4trimethyihexam ethylene- 20 diamine, and a,co-dicarboxylic acids such as azelaic acid, sebacic acid, decanedicarboxylic acid or dodecanedicarboxylic acid, and substituted homologues thereof.

If several compounds or salt pairs are used according to Cl and C2, the condition applies that the average number of the methylene groups in c) per amide group is at least 7. -NH, and -COOH are to be understood as amide-forming groups.

The equivalent weight is the same as the molecular weight for compounds of the type Cl. For salts or stoichiometric mixtures of diamine and dicarboxylic acids of the type C2, it is half the sum of the weight of the dicarboxylic acid and the diamine.

The starting materials for the copolyamides according to the invention are especially suitable for polycondensation in the melt. They are temperature-stable and are not very likely to dicolour 30 during polycondensation, even if temperatures up to 33WC are used and longer reaction times than usual are appropriate.

The copolyamides prepared according to the invention have glass transition temperatures of about 110 to about 19WC and high heat moulding resistance, and exhibit outstanding tough ness, transparence and resistance in boiling water against chemicals and very favourable pro cessing viscosities.

It is particularly advantageous to use an amount of c) so that the glass transition temperature is in the range of 130-180'C. By reduction of the added amount the glass transition tempera ture rises, and vice versa.

By comparison with the transparent copolyamides disclosed in US-A-3842045, US-A-3840501 40 and DE-A-2405985, the copolyamides prepared according to the invention have a higher tran sparence stability in boiling water.

By comparison with the copolyamides described in DE-A-2642244, the polyamides of the invention have higher heat moulding stability, lower strain tear corrosion in alcoholic solvents, greater troughness, lower working viscosity and, further, better transparence and resistance in 45 boiling water or, as the case may be, organic solvents. By comparison with the polyamides described in GB-A-2170209, the products according to the invention can be prepared in shorter reaction times at lower temperatures, and exhibit higher heat moulding stability, higher impact resistance and transparency and improved flow properties, e.g. in the form of a tool.

By the addition of the starting materials according to the invention, it is possible to reach a 50 melt viscosity of less than 2000 Pa.s at 27WC and a load of 122.6 N, which allows problem free processability in the preparation of moulded bodies and on the extrusion of very small dimensional parts.

In general, known methods of polycondensation are used in the preparation of copolyamides according to the invention. The diamines and the dicarboxylic acids must be used in equivalent amounts, in order that copoiyamides with the desired molecular weights are obtained.

Using controlled addition of excesses, usually of diamine but also of dicarboxylic acid, the chain length of the copolyamides can be regulated without the introduction of monoamines or monocarboxylic acids. The components according to a) and b) can be added as such or also as salts.

o)-aminoundecanoic acids can be added directly to the reaction mixture as component Cl). In a preferred embodiment, however, instead of coaminolauric acid, its lactam, laurolactam, is used. This requires that a pressure reaction phase in the presence split the lactarn ring before the desired polyconclensation. ' of water is conducted into order to If, according to C2), a dicarboxylic acid and a diamine are used, they can be added alone or in 65 4 GB2197332A 4 the form of their salts. Salts of straight-chain, a,co-dicarboxylic acids and a,co-diamines can be produced relatively easily. Their use involves no problems of stoichiometry.

In the condensation of the diamines according to a) with isophthalic acid, with a mixture of isophthalic acid and terephthalic acid or a substituted isophthalic acid or an aliphatic dicarboxylic acid and with laurolactam, the mixture of the starting materials (which still contains water) is first subjected to pressure at elevated temperature. Following pressure release, the water is removed during polycondensation under an inert gas (usually nitrogen) or vacuum.

If diamines and dicarboxylic acids alone are used, the neutralisation reaction proceeds, with the addition of some water, at temperatures at which a stirrable mixture or a melt exists, and the temperature is raised gradually. In order that there is no loss of amine, pre-condensation can be 10 conducted in closed systems under pressure; after release of pressure, further polycondensation can be conducted without pressure or under vacuum.

Conventional additives in the preparation of polyamides can be added to the polycondensation mixture before, during or towards the end of the polycondensation; these additives should advantageously be soluble in the copolyamide, for the purposes of transparency. These additives 15 are, for example, antioxidants, flame-retardants, light stabilisers, platicisers, mould separation agents, optical brighteners and pigments. Such additives can be mixed with the copolyamide or worked in by re-melting in suitable apparatus, e.g. in an extruder.

The copolyamides according to the invention are very suitable for processing in so-called injection moulding or extrusion processes, e.g. for the preparation or cladding of optical guides 20 and also for the most various moulded bodies.

A further advantage of the copolyamides according to the invention is that, depending on the melt viscosity of the relevant granulate, they can be used without danger of discoloration at injection temperatures up to 31WC and higher. The material exhibits good flow and deformation properties. In order to improve the mould filling, the tools are tempered, so that the deformabil ity and also the transparency can be influenced positively. A further advantage is that conven tional pulverisation of the granulate with certain slip agents, before further processing, is very economical.

The copolyamides according to the invention can also be alloyed or mixed with other homo-or copolyamides or mixtures thereof or with other plastics materials. For example, this can be 30 achieved by mixing and extruding the granulate or plastics components.

Examples of additional homopolyamides are nylon 12, nylon 11, nylon 6.6, nylon 6.9, nylon 6.10; examples of copolyamides are those which contain the monomers which give the specified homopolyamides, or other copolyamides; examples of other polymers are those which are at least partially compatible with the copolyamides according to the invention.

These co-components are advantageously added in an amount of 0-50% with respect to the resulting alloy. The alloying of a further component with copolyamides prepared according to the invention can change the mechanical properties; for example, the impact strength and notch toughness are generally improved, or the stiffness reduced, thereby.

A further advantage of the copolyamides of the invention is that, if further additives according 40 to c), for example monomers of nylon 12, are used, the transparence stability in boilding water is substantially unaffected.

The following Examples 1 to 11 and 14 to 17 illustrate the invention. Examples 12 and 13 are comparative. In all the Examples (except 5), the diamine bis(4-amino- 3-methyl-5-ethylcyclo- hexyl)methane was used in the form of a selected liquid isomeric mixture (85% trans/trans and 45 cis/trans proportion) as component a).

Example 1 to 11 and Comparative Example 12 and 13 The following Table 1 sets out the conditions used in the various polycondensation tests, in which only one diamine component was used as component a). indicates that a change from 50 the general procedure was made (see below).

Column 2 gives the nature of component c), and column 3 the proportion (% w/w) of component c) based on the total weight of all components a), b) and c). Column 4 gives the equivalent (mol) ratio of the components a), b) and c). Column 5 gives the period and column 6 the maximum reaction temperature.

Results are given in Table Ill: The viscosity nrel was measured as a 0.5% w/w solution in m cresol at 2WC. A DSC 990 apparatus from DuPont (R=5/E, S=200C/min) was used for the T, measurement. The melt viscosity (1 melt) was measured (in Pa.s) with a melt index testing apparatus Goettfert M/21.6 (nozzle length 8 mm, diameter 2.1 mm) at 27WC and a load of 122.6 N. For the measurement of the transparence stability in boiling water, the copolyamide 60 was prepared as platelents and tested in boiling water; Very good =transparence stability of several weeks/good =transparence stability of about 3 days/average =transparence stability of about 1 day/bad =transparence stability of only a few hours.

The bending E modulus was measured for small bodies according to DIN 53, 452 which have been prepared on a laboratory injection moulding machine. Stress crack stability was measured 65 GB2197332A 5 for test bodies (127 x 12.7 x 3.2 mm) in 100% ethanol: the value gives the peripheral fibre stress in N/MM2 after 90 seconds working-in of the ethanol for a test body maintained under a mechanical load.

In Example 5, a bis(4-amino-3-methyi-5-ethylcyclohexyi)methane having a high content (40%) 5 of cis/cis isomers, is used.

In Example 9, component b), otherwise isophthalic acid, was replaced by tert-butylisophthalic acid. In Example 10, 25% of the isophthalic acid were replaced by terephthalic acid. In Example 11, 1, 1 0decanedicarboxylic acid was introduced instead of isophathalic acid.

The components were weighed into a 4 litre condensation apparatus made of steel, which was carefully flushed with nitrogen before and after the introduction. The apparatus was heated 10 carefully to 20WC under nitrogen, with good stirring of the mixture of starting materials. Precondensation is thus induced, and the predominant proportion of the water of reaction distilled into a receiver.

The melt thus became increasingly viscous. The temperature was then gradually increased, and reached 280-300'C after a further hour. After a total condensation period of 4-8 hours, pressure was released and the melt was finely passed into a cold water bath through a bottom valve: the solidified strands were pulverised, using a comminutor, to a granulate which was then dried under vacuum.

Examples 12 and 13 were conducted in accordance with the disclosure of DEA-2642444.

Both copolyamides thus prepared have higher melt visosities, lower bending E moduli and lower 20 stress crack stability than tests of Examples with copolyamides according to the invention.

P Examples 14 to 16 Table 11 sets out tests in which a second diamine is used in addition to bis(4-amino-3-methyi 5-ethylcyclohexyl) methane as component a). Isophthalic acid was always used as component b) 25 and co-aminolauric acid as component c). The results are given in Table Ill.

1 6 GB2197332A 6 E>. a: 7-- 1 e S c c -'ej-jc,-- ratio (h) rea-,t.

Elqu-i ter-,-,--rature a) b) c) PC) t,-Arr-,nc- 32.6 1.06, 1 1.01) 4.0 280 lauric ac-d 2 k-7,inG.'aiiric: 32. 6 1. 06 1 1.03 3.0 280 ac-id 3 L-Ami-now-dec-.19.3 i C.9 1.0 4.5 280 ano-lc acid 4 9, 12-Se-l t 47 1 O.K 1.0 6 28C, 3C i: C. 92: i G 5.5 2K ai=-c acid 6 32 1: 1 c 280 lawic acid 7 --Arr-i-no- 33 i: 0.9E 1.1 6.5 280 la,=.c acid 8 --AirLnc- 3C.5 1: 0.95 1.0 6 2 8 lauric acJ,,.

9 30.7.. OG: 1 1.04 7 280 lauric aci---' lc 30.7 1 C.9 1 7 275 acid i 1.14: l.:.5 2 8C lauric ac-d 12 36.5 1: 1 1 5.5 285 lauric acid 13 L 33.8 1: 0.99 1.05 4.5 285 la,,iri2 acid 1 1 --el secon' YA!e'- 1-a+L-JC Cf a) h) c) di arr i n e t h, c t,, c (equ i d.,ar -nes 14 B -s 4 -a:- ino- SC,: se 1.16: 1 C c y oh e -, v rr.. e t e H c x ar,. e t h,,- '. en E- - -4 1 C 9 0 8E.:

d -ai- i ne 16 B-s (4-ai-,ir.o- 5,C: 5 C 1: 0.98: C. 9 c 3-ineth-,---c,,c'Lo h e >:,,,) rr, e -- h a:-, e 7 GB2197332A 7 TABIE III Example 17

This Example is intended to demonstrate the ability to prepare copolyamides according to the invention in a semi-technical procedure.

16.7 kg of the liquid isomeric mixture of bis(4-amino-3-methyi-5ethylcyclohexyl)methane con taining 85% w/w trans/trans and cis/trans isomers, 11.5 kg laurolactam, 1. 0 g silicone-based anti-foaming agent, 10 kg water and finally 9.4 kg isophthalic acid were introduced into a 150 1 V45A polycondensation autoclave. The autoclave was flushed several times with nitrogen and, after closing, gradually heated to 180'C until a clear melt was obtained. Stirring ensued, at about 45 rpm, and the temperature was raised to 29WC. There was thus a pressure in the autoclave of about 18 bar, which was maintained for 2 hours. Condensation under N2 for 2.5 hours at 28WC followed. Finally, the melt was removed from the autoclave as a cord and comminuted to granulate. After drying, 42 11 equivalent/g carboxyl groups and 18 p equivalent/g amino groups, a nrel of 1.52, q melt of 1260 Pa.s (270'C/122.6 N) and a T, of 163'C were measured. 50 Small DIN beams and DIN tensile rods were obtained from an injection moulding machine at a bulk temperature of 29WC, and on which various mechanical properties were measured.

In an impact resistance test according to DIN 53453, the test bodies did not break, the limiting bending tension according to PIN 53452 was 125 N/MM2, the bending E modulus 2322 N/M2.

The rods exhibited very good hydrolysis and transparence properties in boilding water, and a tension-corrosion-tear resistance of more than 15 N /MM2 after immersion in 100% ethanol for seconds.

The equivalent weight water uptake at 23'C (50% atmospheric pressure was only 1.2%. The dimensional stability of sprayed moulded bodies of the copolyamide according to the invention 60 was excellent.

Sample granulate of this preparation was co-extruded with 25 and 30% w/w polyamide 12 chips. The extrudate thus-obtained was fully transparent and had T, values of 102'C to 90'C.

Exarrple ri re 1 T G r. m'Lt Transparency Be-nd-ing E Crack 5 (OC) (Pa. s) in boiling. Modu lus f or riati a., water W/r=2 1 1.56 162 2024 very good 10 2 1.58E 1E3 2084 very good - - 3 150 880 good 2100 > 12 4 1.56 122 1080 very good 2-120 > 12 15 1.31 130 497 bad 1890 > 9 6 1.515 1146 2089 ve-r-) gocxj 2129 > is -7 1.524 1941 good, 2060 > 13 20 1 16 8 1.39 16 1640 ve-v Good 2100 > 12 9 1. 3 77 1 '12 4 7 6 good 2520 > 11 1.46 150 960 good 2380 > 25 11 1.51 146.5 1220 good 1944 1.68 156 2146 good 1632 > 2.5 13 2 154 1900 good 1816 > 4 1.5 30 14 1.56 148 1260 ve-r-v good - 1.47 138 2 good 3K 16 1,541 156 1982 ver,, good 35

Claims (13)

1. 8 GB2197332A 8 1. A transparent copolyamide obtainable by polycondensation of a diamine component com prising bis(4-amino-3-ethyl-5-methlcyclohexyl)methane with isophthalic acid and, optionally, tere phthalic acid or aliphatic dicarboxylic acids, and further polyamide- forming components having 6 or more C atoms.
2. 2. A copolyamide according to claim 1, wherein the bis(4-amino-3-methyl-5ethy[cyclohexyl)- 5 methane is predominantly in trans/trans and/or cis/trans form.
3. 3. A transparent copolyamide according to claim 1 or claim 2, wherein the diamine compo nent comprises a further diamine, and the molar ratio of the two dimaines is 0.9:0.1 to 0.1:0.9.
4. 4. A copolyamide according to claim 3, wherein the further diamine is selected from bis(4- 10 amino-3-methylcyclohexyl) methane, bis(4-amino-3,5-d iethylcyclohexyl) methane, bis(4-amino-3-me thyl-5-isop ropylcyclohexyl) methane, bis(4-aminocyclohexyl) methane, 2,2bis(4-aminocyclohexyl) propane, 1,3-bis(aminomethyl)cyclohexane, 3-aminomethyl-3,5,5- trimethylcylohexylamine, 2,4,4 (2,2,4)-trimethylhexamethylenediamine, 3(4),8(9)bis(aminomethyl)tricyclo[5.2.1.02,6]decane, 2,6-bis(aminomethyl)norbornane and m-xylenediamine.
5. 5. A copolyamide according to any preceding claim, wherein the acid component comprises isophthalic acid alone, a mixture of isophthalic and terephthalic acids containing up to 50% (mol or by weight) terephthalic acid, or a mixture of 2-95% w/w isophthalic acid and 98-2% w/w aliphatic dicarboxylic acid.
6. 6. A copolyamide according to any preceding claim, wherein the further polyamide-forming components having 6 or more C atoms form 20 to 60% wt. of the total amount of the transparent copolyamide and comprise o)aminocarboxylic acids or their lactams having more than 8 C atoms and/or a salt or a stoichiometric 1:

   1 mixture of an aliphatic dicarboxylic acid and an aliphatic diamine, wherein the condition applies that there is an average number of at least 7 methylene groups per amide group or per pair of amide-forming groups, and the minimum number of methylene groups between the amide-forming groups is 6, and wherein, further, when part of the isophthalic acid is replaced by an aliphatic dicarboxylic acid, the sum of the weights of these aliphatic dicarboxylic acids and the said polamide-forming components must lie in the range of 20-60% by weight, based on the total amount of the transparent copolyam- ide.
7. 7. A polyamide according to claim 6, wherein the aliphatic dicarboxylic acid is an a,(0 poly methyl e ne-d ica rboxylic acid and the aliphatic diamine is an a,(O- polymethylenediamine.
8. 8. A copolyamide according to any preceding claim, wherein the bis(4amino-3-methyl-5 ehtylcycl ohexyl) methane consists of at least 80% trans/trans and/or cis/trans isomers.
9. 9. A copolyamide substantially as described in any of Examples 1 to 11 and 14 to 17.
10. 10. A mixture of a copolyamide according to any preceding claim with another polyamide.
11. 11. A mixture according to claim 10, wherein the other polyamide is polyamide 11 or 12 or a copolyamide thereof.
12. 12. A cladding material, for opto-electronic conducting systems, which comprises a product according to any preceding claim.
13. 13. A moulded body prepared from a product according to any of claims I to 11.

    Pubi is hed 1988 at The Patent Office, State House, 66/71 High Holborn, London WC1R 4TP Further copies maybe obtained from The Patent Office Sales Branch, St Mary Cray, Orpington Kent BR5 3RD Printed by Burgess & Son (Abingdon) Ltd Con 1/87 1