DE2642244C2 - Process for the production of crystal clear, transparent copolyamides and their use for the production of moldings - Google Patents

Description

a) Bis- {4-arieo> -3-methylcyclohexyl) -raethane
or mixtures thereof with 4,4'-diaminodicyclohexylmethane or with 2,2-bis- (4-aminocyclohexyl) propane in a molar ratio of 1: 1

b) the approximately stoichiometric amount, based on component (s) a), of isophthalic acid, which can be replaced by 0 to 50% (mol or weight) terephthalic acid, and where up to IS mol%, based on the total amount of acid or said mixture of acids, may be replaced by other polyamide-forming walls dicarboxylic acids,> _

, and with

c) 30 to 40 Gäw .-% of the sum of a), b) and c) a further polyamide-forming component, which el) an ω-aminocarboxylic acid or its lactam with more than 9 carbon atoms or c 2) a salt or a represents a stoichiometric l: l mixture of an aliphatic dicarboxylic acid, in particular an a, ω-polymethylene dicarboxylic acid, and an aliphatic diamine, in particular an α, ω-polymethylene diamine,

polycondensed, with the condition that the average number of methylene groups in c), based on one amide group or one pair of the amide-forming groups, is at least 9 and the minimum number of methylene groups between the amide-forming groups is at least 6, and furthermore in the case of replacement of one Part of the isophthalic acid by an aliphatic dicarboxylic acid is the sum of the parts by weight of these aliphatic dicarboxylic acid and the additive c) in the range from 30 to 40 wt .-%, based on the Sum of a), b) and c) must be.

2. Use of the copolyamides produced according to claim 1 for the production of moldings.

Using 4,4'-diaminodicyclohexyl or diamines of the dicycan type [bis- (4-aminocyclohexyD-alkane, those in the cyclohexyl radicals can be substituted by methyl groups] Polyamides and copolyamides have been known for a long time.

In GB-PS 6 19 707 and in US-PS 24 94 563 described polyamides from 4,4'-diaminodicyclohexyl or from diamines of the dicycan type and from Dicarboxylic acids, such as adipic acid or sebacic acid, are transparent if they are used in their production 25 ° C liquid isomer mixtures of these diamines are used. The processability and more Properties such as transparency resistance to boiling water, resistance to organic Solvents and hydrolysis resistance, these transparent polyamides leave something to be desired left over.

The transparent polyamide described in US Pat. No. 2,696,482 from the isomer mixtures which are liquid at 25.degree of 4,4'-diaminodicyclohexylmethane and of isophthalic acid has good resistance to hot water »For an advantageous course of the polycondensation one has to use the diphenyl ester run out of isophthalic acid or the polycondensation mixture Add phenol as a solvent or plasticizer. Because of the high softening temperature and the high melt viscosity of this transparent polyamide, its maximum water absorption 7.75% are processing temperatures

ίο around 330 ° C required. It also has similar disadvantages the transparent polyamide of bis (4-amino-3-methylcyclohexyl) methane described in US Pat. No. 2,516,585 and from terephthalic acid.

In US-PS 38 47 877 described transparent

is copolyamides from 4,4'-diaminodicyclohexylmethane, from terephthalic acid and / or isophthalic acid and from e-caprolactam show a similarly high water absorption capacity and tend to become cloudy after a few days when treated with boiling water.

They also contain proportions of unreacted, monomeric e-caprolactam, which makes them useful restricts or makes impossible in many areas. The latter also applies to those in the DE-OS 15 95 354 et al. described transparent copolyamides from 2,2-bis- (4-aminocyclohexyl) -propane, Dicarboxylic acids and c-caprolactam, which are soluble in methanol if they are more than 20% by weight ε-caprolactam and / or another conventional polyamide former, e.g. B. hexamethylenediamonium adipate, included condensed. As far as the transparent polyamides described in DE-OS 15 95 354 only from 2,2-bis (4-aminocyclohexyl) propane and a dicarboxylic acid, such as adipic acid, have Although they have better solvent resistance, they are hardly due to their very high softening points processable because it is hardly possible to manufacture stress-free molded parts from them.

The transparent copolyamides of 4,4'-diaminodicyclohexylmethane described in US-PS 35 97 400, Hexamethylenediamine, terephthalic acid and isophthalic acid have a much too high water absorption capacity on. Thus, when these transparent copolyamides are stored in water, their softening points become lowered to 50 to 60 ° C.

The transparent described in US-PS 38 42 045 Copolyamides are polycondensation products of 4,4'-diaminodicyclohexyl methane, which leads to 40 up to 54% is in the trans-trans configuration, with a mixture of 50 to 70 mole% decanedicarboxylic acid-1,10 and 30 to 50 mole percent suberic acid or azelaic acid.

Transparent copolyamides made from 2,2-bis (4-aminocyclohexyl) propane and / or its methyl derivatives and from dicarboxylic acid mixtures, 20 to 65 mol% of which are from adipic acid and 35 to 80 mol% Suberic acid, azelaic acid, sebacic acid and / or decanedicarboxylic acid-1.10 are in the US-PS 38 40 501 described.

CH-PS 4 49 257 relates to transparent polyamides made from decanedicarboxylic acid-1.10 and from diamines Dicycan types, inter alia. Bis (4-amino-3-methylcyclohexyl) methane or 2,2-bis (4-aminocyclohexyl) propane.

The flame-retardant thermoplastic molding compositions described in DE-OS 24 05 985 contain in addition to red phosphorus, a transparent polyamide or mixtures of two or more transparent polyamides. Transparent polyamides include: also called those composed of 35 mol% 4,4'-diaminodicy-

lohexylmetban u - "er 2,2-bis (4-aminocyglobexyl) propane, 35 MoJ% isophthalic acid and 30 mol% ω-aminoundecanoic acid, ω-aminolauric acid (or its Lactams) or a stoichiometric mixture of dodecamethylenediamine and decanedicarboxylic acid-1.10 derive. The monomer mixtures to be used for the production of these polyamides consist of 33 or 31.5% by weight of ω-aminolauric acid or the stiometric mixture of dodecamethylenediamine and decanedicarboxylic acid-1.10.

Surprisingly, it has now been found that when using a certain diamine of the dicycan type as well as other certain polyamide-forming components that are crystal-clear in certain proportions (Transparent) copolyamides are obtained which have good mechanical properties with good processability as well as having excellent transparency resistance in boiling water and beyond with other polyanpids, e.g. B. Nylon 12, real plastic alloys with full preservation of transparency.

The process according to the invention for producing crystal-clear, transparent copolyamides using of diamines of the dicycan type and other polyamide-forming components is characterized by that he

a) Bis- (4-amino-3-methylcyclohexyI) methane or its Mixtures with 4,4 ° -diaminodicyclohexylmethane or with 2,2-bis- (4-aminocyclohexyl) -propane in a ratio of 1: 1 with

b) the approximately stoichiometric amount, based on component (s) a), of isophthalic acid, which can be replaced by 0 to 50% (MoS oderüewicbtJ terephthalic acid, and where 15 mol%, based on the total amount of the acid mentioned or the acid mixture, by further polyamide-forming Dicarboxylic acids can be replaced, and with

c) 30 to 40% by weight of the sum of a), b) and c) of a further polyamide-forming component, which c 1) an ω-aminocarboxylic acid or its lactam with more than 9 carbon atoms or c 2) a salt or a stoichiometric 1: 1 mixture of an aliphatic dicarboxylic acid, in particular an α, ω-polymethylene dicarboxylic acid, and an aliphatic diamine, in particular an α, ω-polymethylene diamine, represents

polycondensed, with the condition that the average number of methylene groups in c), based on each amide group or on each pair of the amide-forming groups, is at least 9 and the The minimum number of methylene groups between the amide-forming groups is at least 6, and further, in the case of replacing part of the isophthalic acid with an aliphatic dicarboxylic acid Sum of the proportions by weight of this aliphatic dicarboxylic acid and the additive c) in the range from 30 to 40 % By weight, based on the sum of a), b) and c)

If several compounds or salt pairs are used according to el) and c2), the condition that applies the average number of methylene groups in c), based on one amide group or one pair of each amide-forming groups, at least 9, for the sum of all additives used. Among amide-forming Groups mean the pairs -NHi and -COOH.

The bis (4-amino-3-methylcyclohexyl) -metban, the 2,2-bis (4-aminocyclQhexyl) propane and 4,4'-diaminodicyclohexyl methane are in the form of the usual, e.g. B, isomer mixtures that are liquid at 25 ° C are used

The acid component according to b) is preferably isophthalic acid alone or commercially available Mixtures of isophthalic acid and terephthalic acid containing up to 50% (mole or weight) terephthalic acid th, in question.

If up to 15 mol% of the isophthalic acid or of the isophthalic acid-terephthalic acid mixture by further polyamide-forming dicarboxylic acids are replaced, dicarboxylic acids are more advantageous as such Acids containing more than 6 carbon atoms are possible, in particular suberic acid, azelaic acid, sebacic acid, 1.10 decanedicarboxylic acid and its homologues substituted in the side chain. Preferably no other polyamide-forming dicarboxylic acids are used.

The following are particularly suitable as third polyamide-forming components according to c):

for el): ω-aminolauric acid or preferably its Lactam or ω-aminoundecanoic acid,

for c2): salts of the following diamines and dicarboxylic acids, namely α, ω-diaminoalkanes and β, ω-alkanedicarboxylic acids and their homologues substituted in the side chain. Diamines: 1,6-diaminohexane, 1,8-diamino-

^JI> octane, 1,9-diaminononane, 1,10-diaminode

can, 1,12-diaminododecane, trimethylhexamethylenediamine.

Dicarboxylic acids: azelaic acid, sebacic acid or decanedicarboxylic acid-IO.

For compounds of type el) the equivalent weight is identical to the molecular weight. For salts or stoichiometric mixtures _r ^ us diamine and dicarboxylic acid of type c2), it is half the sum of the weight of the dicarboxylic acid and the diamine.

The starting materials used in the process according to the invention are well suited for the polycondensation in the melt. They are temperature-resistant and tend, for example in contrast to the hexamethylenediamine adipic acid salt (which is excluded by the above condition) hardly to be discolored during the polycondensation, even when temperatures of 280 to 320 ° C are used.

The copolyamides according to the invention have glass transition temperatures of about 140 to 170 ⁰ C and exhibit resistance to transparency in boiling water, among others several weeks. Especially advantageous is the addition amount c) adjust so in genannen a range that the glass transition temperature in the temperature range of 150 to 170 ⁰ C, with increases by reducing the addition amount of the glass transition temperature and by increasing the Zusatzmuige

bo drops.

Compared to the transparent copolyamides according to the teachings of US-PS 38 42 045, US-PS 38 40 501 and DE-OS 24 05 985, the copolyamides prepared according to the invention are characterized by a higher Persistence of transparency in boiling water.

The melt viscosity of the copolyamides produced according to the invention at 300 ° C. is medium

Degrees of polymerisation of the polymer from 80 to 200, where each building block is viewed as a chain link, about 2,000 to 15,000 poise, especially about 4,000 up to 10,000 poise, this guarantees perfect processability on injection molding machines.

In the method according to the invention, in general known polycondensation methods are used. There must be diamine and dicarboxylic acid are present in equivalent amounts so that one can Copolyamides with the required molecular weights arrive with carefully used excesses The chain length of the copolyamides can be regulated in diamine or dicarboxylic acid. The chain length can also be done by adding a calculated amount of monoamine or monocarboxylic acid to the reaction vessel can be limited. The components according to a) and b) can be used individually or in the form of their salts.

ω-Ainoundecanoic acid as component el) is directly added to the reaction mixture, while instead of the ω-aminolauric acid preferably its lactam, the laurolactam, is added to the reaction mixture. However, this requires the implementation of a printing phase before the actual polycondensation, so that the laurolactam ring is broken down.

If a dicarboxylic acid-diamine pair is used according to c2), so acid and amine can be added individually or added in the form of their salt. Salts out straight chain α, ω-dicarboxylic acids and α, α'-diamines can be represented relatively easily. When using pure salts, there are no stoichiometric problems on.

In the condensation of the diamines according to a) with isophthalic acid or with an isophthalic acid-terephthalic acid mixture and with laurolactam as component el) the mixture of starting materials, which is still contains some water, first pressurized to open the lactam ring. Afterward the pressure is released and the water is drawn off under inert gas or vacuum during polycondensation.

If diamines and dicarboxylic acids are added individually, the neutralization reaction takes place with the addition of some water at temperatures at which a stirrable suspension or melt is already present, whereupon the temperature is gradually increased. Pre-condensation can be used to prevent amine losses take place in a closed system under pressure. Then it is relaxed, after which you still have to can pass a vacuum stage, e.g. B. gradually increasing the reaction temperature.

The polycondensation mixture can before, during or towards the end of the polycondensation at the Production of polyamides customary additives, which are advantageous because of the influence on transparency should be soluble in polyamide, are added. These are, for example, light and heat stabilizers, z. B. aromatic amines such as diphenylamine, phosphorus compounds such as phosphorous acid, and soluble Metal complexes, e.g. B. of copper or manganese, dyes, optical brighteners, plasticizers, mold release agents, Flame retardants and, in the event that the transparency of the polyamides plays a less important role plays as their mechanical properties, also reinforcement materials such as glass fibers or asbestos fibers, Glass beads or mineral fillers. Many of these additives can of course also be rolled up and in the copolyamide materials are extruded in.

The copolyamides prepared according to the invention are well suited for the preparation of the most diverse Molded parts in the so-called injection molding process. Depending on the melt viscosity of the granules used, Injection temperatures of 270 to 310 ° C or, if necessary, higher temperatures can be used, with the risk of discoloration is low. The materi & i shows good flow and mold release properties. To get a better shape filling, the tools can be tempered without affecting the demoldability. Generally one is not necessary Powder the granules with lubricants such as calcium or magnestum stearate.

Copolyamides produced according to the invention can also be mixed or alloyed with other homopolyamides or copolyamides or mixtures thereof, which z. B. can be done by mixing the granules of the polyamides and then performing a coextrusion. As additional homopolyamides, for example, N ' ^J .on 12. Nylon 6 or nylon 66 come into consideration, as copolyamides, for example, those which contain the monomers which lead to the homopolyamides mentioned. These co-component (s) are preferably added in an amount of 0 to 50% by weight, based on the resulting alloy. By adding a further component to the copolyamide produced according to the invention, its mechanical properties can be changed; for example, the impact strength or notched impact strength is generally improved as a result. If a polyamide from the monomers mentioned under c) is used as an additional component, for example nylon 12, the resistance to transparency of the alloy in boiling water is only slightly affected.

Examples 1 to 7

In these examples, bis (4-amino-3-methylcyclohexyl) methane was always used as component a) in the form A commercially available liquid mixture of isomers is used.

In Examples 1 to 6, isophthalic acid, which contained 5 mol% terephthalic acid, was used as component b) used. In example 7, al3 component b) Isophthalic acid, which contained 15 mol% terephthalic acid, was used.

The type and weight proportions of the components c) used, based on the sum of all used Components a), b) and c) are listed in Table I.

The components were placed in a condensate apparatus weighed out of glass and completely replaced the air with nitrogen. The apparatus was turned into a Immersed molten salt and the temperature while stirring the mixture of starting materials to about 230 ° C raised. The precondensation started. Most of the water of reaction distilled off. the The melt became increasingly viscous. Therefore, the temperature has now been increased successively, a value of 280 to 300 ° C. was reached after about 1 hour. After a total condensation time from 3.5 to 6 hours the stirrer was removed from the melt and this was switched off after solidification knocked out the glass tube. On the completely transparent copolyamides were those in the following Table 1 specified property values determined.

7th I. Component c)
Art Wt% 26 42 Aq
ver
Koi
a) jivile
faucet
Tipon
b) nz-
s the
ducks
c) 244 280 Own
^ rel. 8th 2,700 transparency
resistance
in boiling
water Tabel ω-aminolauric acid 36.5 1 1 1.1 280 1.46 4,400 very good example ω-aminoundecanoic acid 37 1 1 1.2 Condensation
conditions
Time temp,
tot. (h) max. ( ⁰ C) 280 1.46 property values
TG enamel
( ⁰ C) viscosity
(Poise) 6,000 Well I. 12.12 salt 36.5 1 1 1.1 3.8 280 1.53 156 12,000 Well 2 12.10 salt 37 1 1 1.2 3.5 300 1.59 157 60,000 Well 8.10 salt 38.2 1 1 1.47 4.0 280 1.78 153 3,000 Well 4th ω-aminolauric acid 32.0 1 1 0.89 5.5 280 1.459 170 17,000 Well 5 ω-aminolauric acid 36.5 1 1 1.1 6.0 1.626 161 very good 6th 6.0 175 7th 6.0 160

Tg ( ⁰ C):

The ones used in I ami and in other i ami Terms are defined as follows:

Equivalence ratio: Here, for the purpose of a direct comparison option for component c), where partly ω-aminocarboxylic acids and partly salts were used, the formula unit per pair related amide-forming groups.

Time dead. (H): Total condensation time in hours

the.

Temp. Max. ( ⁰ C): Maximum condensation temperature in the end phase of the polycondensation.

μΓβΙ .: Relative solution viscosity, gemes

sen on a 0.5% solution of the copolyamide in m-cresol.
Glass transition temperature, measured on a dried sample of the copolyamide with a differential calorimeter, type IB, from Perkin-Elmer at a heating rate of

32 ° C / min and a sensitivity according to R 16.

This is a measure of the flow behavior of the copolyamide melt and was measured at a melting temperature of 290 ° C and a load of 12.5 kp with a melt index device from the company Goettfert type MFI 21.6 using a nozzle 8 mm long and 2.1 mm in diameter certainly.

Transparency resistance in boiling water:

very good: a tile shows a trans

parence resistance in boiling water for several weeks. A plate has a transparency resistance in boiling water of approx. 3 days.
A plate has a transparency resistance in boiling water of approx. 1 day.

Melt viscosity
(Poise):

middle:

medium: tin mttcnen has an Iranian

parence resistance in boiling water for about 1 day.

bad: a platelet is in boiling

Water cloudy within a few hours.

Examples 8 and 9
as well as comparative experiments 1 to 4

A 1: 1 was used as component a) in example ο Mixture (Moiteile) of bis (amino-3-methylcyclohexyl) methane and 4,4'-diaminodicyclohexyl methane and in Example 9 a 1: 1 mixture (molar parts) of bis (4-amino-3-methylcyclohexy!) methane and 2,2-bis (4-aminocyclohexyl) propane used. In Examples 8 and 9, component b) was isophthalic acid, which contained 5 mol% terephthalic acid. The component c) was ω-aminolauric acid in both examples. The molar ratio (= equivalence ratio) of the components a: b: c in Examples 8 and 9 was always 1: 1: 1.1.

In comparative experiment 1 - according to the teaching of DE-OS 24 05 985 - 4,4'-diaminodicyclohexylmethane, Isophthalic acid with a content of 5 mol% terephthalic acid and ω-aminolauric acid in a molar ratio (= Equivalence ratio) of 1: 1: 1.1 are used.

In comparative experiment 2 - according to the teaching of DE-OS 15 95 354 - 2,2-bis (4-aminocyclohexyl) propane, an equimolar amount of isophthalic acid, which contained 5 mol% terephthalic acid, and 24.8

thus% by weight of caprolactam, based on the sum of all components, is used

In comparative experiment 3 - also in accordance with the teaching of DE-OS 15 95 354 - the same results Components used, but here the amount of caprolactam, based on the sum of all components, was 34 wt%.

In comparative experiment 4 - according to the teaching of US-PS 38 47 877 - one went from 4,4'-diaminodicyclohexylmethane, an equimolar amount of isophthalic acid containing 5 mol% terephthalic acid, and, based on the sum of all components, 32.4% by weight of caprolactam.

The following table Π gives the condensation conditions and the property values obtained.

Table II

Condensation conditions time temp,

tot. (h) max. ( ⁰ C)

Property values

f7rel. TO melt transparency (° () viscosity resistance
(Poise) in boiling
water

Example 8 1 3.5 280 Example 9 2 5.0 300 Comparative experiment 3 6.3 280 Comparative experiment 4th 5.0 280 Comparative experiment i s 5.5 280 Comparative experiment 5.5 280 Be game 10

In a polycondensation autoclave, 11.50 kg of the liquid isomer mixture of bis (4-amino-3-methylcyclohexyl) methane and 10.50 kg of laurolactam were stirred with 3 kg of water while slowly heating to 180.degree. Then sprinkled with stirring over ¹ A hour 8.0 kg isophthalic acid, 5 mole% terephthalic acid contained in the melt so that a homogenous suspension was created, which was still 29 g benzoic acid and 3 g of antifoaming agent Silicon-based zusetzte. The autoclave was now sealed gas-tight, with the melt being under a cushion of steam. The melt was heated to 280 ° C. with continued stirring. A pressure of 20 atmospheric pressure built up during this process, which was maintained for 1 hour. The pressure was then slowly reduced to atmospheric pressure and the melt was then condensed ^{under a stream of nitrogen at 280 ° C. for 2 hours.} Finally, the melting temperature was increased to approx. 300 ° C. and the mixture was stirred for a further 4 hours until no increase in viscosity could be found in the melt.

The copolyamide was discharged from the autoclave and granulated. Its relative solution viscosity was 1.512 and the melt viscosity at 280 ^° C. was 10,500 poise, measured under a load of 12.5 kg. Its glass transition point was 151 ° C.

ASTM tensile bars and small din bars were placed on an injection molding machine at a cylinder temperature of 280 ° C injected and tested for the mechanical properties.

The flow strength and the breaking strength, depending on DIN 53 455, were 950 and 650 kp / cm ² . The limit bending stress according to DIN 53 452 was determined to be 1200 kp / cm ² . When the impact strength was determined in accordance with DIN 53 453, no breakage of the material occurred. The notched impact strength of the material according to DIN 53 453 was 2 cm kp / cm ² . The material had a spherical

1.622 147 10,000 Well 1.677 151 24,000 Well 1.633 143 7,000 middle 1.526 189 30,000 Well 1.505 150 11,000 bad 1,507 147 17,000 bad

pressure hardness according to VUK 03Ö2 after όϋ seconds of 1100 kg / cm ² .

As a result of the very low moisture absorption, the mechanical properties of the changed Material in water only a little. The dimensional stability of injection-molded molded bodies from the inventive copolyamide produced was very good.

Examples 11 and 12
as well as comparative tests 5 to 10

In Example 11, 1.03 mol were as component a) Bis- (4-amino-3-methylcyclohexyl) methane, as component b) 1 mole of isophthalic acid and as component c) 1.1 mol of 12-aminododecanoic acid used. The weight fraction of the 12-aminododecanoic acid, based based on the sum of all components, was 36.5% by weight. In Example 12, 1.01 mol of bis (4-amino-3-methylcyclohexyl) methane were used as component a) b) 1 mol of isophthalic acid and 1.07 mol of laurolactam as component c). The weight percentage of the laurolactam, based on the sum of all components, was 34.0% by weight. The polycondensation took place as described in Example 10.

In comparative experiments 5, 6 and 7, the examples were 1, 2 and 3 of DE-OS 24 05 985, but without the addition of red phosphorus, reworked exactly.

In comparative experiments 8, 9 and 10, according to the teaching of DE-OS 24 05 985, 1.03 mol 1,3-bis (aminomethyl) cyclohexane and 1 mole of isophthalic acid with 0.5 mole, 0.4 mole or 0.35 mole 12-

Aminododecanoic acid polycondensed. The weight The proportion of 12-aminododecanoic acid, based on the sum of all components, was 25.6 % By weight, 21.6% by weight or 19.4% by weight,

The following Table III shows the superior performance of the copolyamides prepared according to the invention in boiling water.

Table III

^ rel. Melt viscosity Tg

at 270 ⁰ C and a ( ⁰ C) load of 12.5 kp behavior in boiling water
Shape retention of the

persistence transparency

Example 11 1.46 10,000 154 dimensionally stable remains Example 12 1.53 25,000 154 dimensionally stable remains Comparison trial 5 1.56 50,000 142 glued no Comparative experiment 6 1.43 34,000 142 glued no Comparative experiment 7 146 glued no Comparative experiment 8 1.66 147 soft no Comparative experiment 9 1.82 154 soft no Comparative experiment 10 1.96 158 soft no

Further comparative tests
There were made

a) a copolyamide according to the application made from Bie- (4-amino-3-methylcyclohexyl) methane, Isophthalic acid and ω-aminolauric acid in a molar ratio 1: 1: 1.1,

b) a copolyamide according to the teaching of DE-OS 24 05 985 from 2,2-bis (4-aminocyclohexyl) propane. Isophthalic acid and ω-aminolauric acid im Molar ratio 1: 1: 1.1,

c) a polyamide according to the teaching of CH-PS 4,49,257 from bis (4-amino-3-methylcyclohexyl) methane and decanedicarboxylic acid-1.10 in a molar ratio of 1: 1,

d) a polyamide according to the teaching of CH-PS 4 49 257 from 2,2-bis- (4-aminocyclohexyl) -propane and Decanedicarboxylic acid-1.10 in a molar ratio of 1: 1.

In order to achieve products with the best possible uniformity of the chain length, all experiments 0.5 mol% of the salt of cyclohexylamine and benzoic acid was added as a chain regulator, and it was in each case worked with an excess of 1 mol% of the diamine.

The polycondensation takes place in a glass apparatus in the form of a glass tube melted shut at the bottom Openings in the upper part for the passage of nitrogen and for the introduction of a metal stirrer. The starting materials (30 g batches) were weighed in and, after the air had been displaced by nitrogen, the polycondensation was carried out started by slow heating. The melts were stirred as soon as possible. To the To avoid amine losses, the melts were initially left at 220 ° C. for one hour and then heated then to 280 ° C. and kept the melts at this temperature for 5 hours with stirring. It then became the The stirrer was removed, the mixture was cooled under nitrogen and the resulting polymer was then removed and crushed.

The alloy tests of the copolyamides or polyamides a), b), c) and d) with nylon 12 were carried out as follows:

800 mg of the respective copolyamide or polyamide and 200 mg nylon 12 were dissolved together in 100 μl formic acid at 60.degree. The solutions were slowly precipitated in 1.5 liters of water with stirring. After standing overnight, the mixture was decanted, suction filtered, washed neutral and dried in vacuo at 80.degree.
For an exact comparison of the alloy behavior, the powder mixtures were melted and cooled, and the melting and solidification behavior was investigated by DSC (Differential Scanning Calorimeter). For this purpose, 10 mg of the respective powder mixture were heated on the thermal system 990, DuPont, with the setting R = 5 at a heating rate of 20 ° C / min to 280 ° C, left there for 180 seconds and then the resulting melt with a cooling rate of 10 ° C / min cooled to a final temperature of 50 ° C. Then the solidified sample was melted again under the same conditions.

On remelting, only a glass transition point was found in the case of the mixture of the copolyamide a) and nylon 12 according to the application at 111 ° C., while in the case of the mixtures of nylon 12 and the copolyamide b), d ^j m polyamide c) and the Polyamide d) in each case the melt band of the nylon 12 was still clearly visible at 175 ° C. With the mixture of nylon 12 and the polyamide

c) there was also a second melting band at 228 ° C., which was also the case when melting again remained.

Surprisingly, this shows that only genuine plastic alloys from the copolyamide a) according to the application result with nylon 12, whereby the glass transition point is after due to the alloyability Desired can be set in a targeted manner in a wide range. In this area also remains due of the formation of real alloys, the transparency is fully preserved.

The real alloyability of the copolyamide according to the application a) with nylon 12, which makes it possible adapt the softening temperature of this copolyamide to the respective requirements in a simple manner, without having to accept any loss of transparency, was also carried out on a large scale confirmed. When mixing a granulate made from 80% by weight of one produced in an autoclave on a 1000 kg scale Copolyamides a) and of 20% by weight nylon 12 (medium-viscosity injection molding type) on a laboratory twin-screw kneader at a melting temperature of 270 ° C., a transparent strand with a glass transition point resulted of 112 ° C, from which the injection molding

drive absolutely transparent injection molded parts, such as small DIN bars, were made. The glass transition point was 125 ° C if only 15% by weight nylon 12 were added and the same procedure was followed.

Table IV below gives the data for the copolyamides or polyamides a), b), c) and d), the resistance of other transparency in boiling water and regain alloyability with nylon 12.

Table IV

Copolyamide rel. TG Σ of the end groups Mol. Wt. Persistence of Alloyability with or polyamide ( ⁰ C) -COOH + -NH ₂ + from end Transparency in Nylon 12 under from the controller groups boiling water Keeping the Trial time: 1 month transparency

a) 1.52 154 184.5 10 800 given given b) 1.55 155 179.9 11 100 given not given c) 1.58 147 163.2 12 250 given not given d) 1.58 152 157.7 12 700 given not given

Claims (1)

Patent claims: 1. Process for the production of crystal clear see-through Copolyamides using diamines of the dicycan type and other polyamide-forming Components, characterized in that one