GB1590529A

GB1590529A - Polyamides

Info

Publication number: GB1590529A
Application number: GB1753479A
Authority: GB
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1976-08-04
Filing date: 1977-07-27
Publication date: 1981-06-03
Also published as: JPS5318697A; GB1590528A; FR2360621A1; FR2360621B1; NL7708388A; GB1590530A; IT1079370B; CH631727A5; DE2635085A1

Description

PATENT SPECIFICATION ( 11) 1590 529

X ( 21) Application No 17534/79 ( 22) Filed 27 July 1977 ( 62) Divided out of No1 590 528 ( 19 ( 31) Convention Application No 2 635 085 X ( 32) Filed 4 Aug 1976 in U: ( 33) FedRep of Germany (DE) l _ ( 44) Complete Specification published 3 June 1981 ( 51) INT CL 3 C 08 G 69/26 ( 52) Index at acceptance C 3 R 22 C 22 D 1 AX 22 D 1 B 2 22 D 2 A 2 22 D 2 B 3 22 D 2 BX 22 M 7 22 N 1 B C 14 B C 22 C 23 C 24 C 33 B C 5 B 1 C 6 X SP C 3 Y B 262 B 263 B 270 B 284 B 285 G 220 G 310 G 315 G 330 H 600 ( 72) Inventors WERNER NIELINGER, BERT BRASSAT, HUGO VERNALEKEN and LUDWIG BOTTENBRUCH ( 54) POLYAMIDES ( 71) We, BAYER AKTIENGESELLSCHAFT, a body corporate organised under the laws of the Federal Republic of Germany, of 509 Lever-kusen, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: 5

This invention relates to copolyamides of isophthalic acid, hexamethylene diamine and certain cyclic aliphatic diamines.

Polyamides of isophthalic acid and hexamethylene diamine are known (U S.

Patent Nos 2,715,620 and 2,742,496) but because of their insufficient dimensional stability at elevated temperatures and their insufficient glass transition temperature 10 they cannot be used for numerous applications It has therefore been proposed to solve this problem by preparing copolyamides with terephthalic acid.

Although the melting point of the products is thus raised, their glass transition temperature is not raised The glass transition temperature is the essential property determining the extent to which amorphous polymers can withstand, thermal 15 stresses.

It has now surprisingly been found that the glass transition temperature of polyamides obtained from isophthalic acid and hexamethylene diamine can be raised by partially replacing the hexamethylene diamine with certain cyclic aliphatic diamines 20 The present invention therefore relates to copolyamides consisting essentially of from 50 to 99 9 mol %, preferably 60 to 90 mol %, of units (A) having the structure:

0 -c :-C ELC-N_(CH 2) 625and 25 and 25 and from 50 to 0 1 mol %, preferably 40 to 10 mol %, of units (B) having the structure:

1.590529 2 wherein R denotes ( 1) a bis-(aminocyclohexyl)-alkane group of the formula:

H (R')2 H 5 -N c 1 Nwherein one R' group denotes methyl and the other R' group denotes hydrogen or methyl, and optionally ( 2) a heterocyclic amine group of the formula:

%(R")_z wherein R" denotes methyl or ethyl, 10 the R" radical being the same or different, and z represents 0, 1 or 2, the sum of A and B being 100 mol %.

The present application and our copending Application No 79 17535 (Serial No 1590530) are both divided from Application No 31543/77 (Serial No 1590528) 15 which describes and claims similar copolyamides in which R represent a cycloaliphatic diamine group of defined formula.

The copolyamides are generally prepared by heating the mixture of isophthalic acid, hexa-methylene diamine and at least one of the above mentioned diamines first to temperatures of between 190 C and 230 C After this pre 20 condensation, poly-condensation is completed at temperatures of between 240 C and 300 C.

Precondensation may be carried out with or without the addition of water and it may be carried out at atmospheric pressure or under the vapour pressure of water in sealed autoclaves 25 The polycondensation is advantageously carried out using salts of the monomers.

The amine mixture is composed of 50 to 99 9 mol %, preferably 60 to 90 mol % of hexa-methylene diamine and 50 to 0 1 mol %, preferably 40 to 10 mol %, of the other diamines 30 The optimum proportion of hexamethylene diamine to cyclic aliphatic diamines depends to some extent on the additional diamines used.

Any loss in diamine occurring during poly-condensation is compensated by using an appropriate excess of hexa-methylene diamine.

The cyclic aliphatic diamines used can be selected from e g bis 35 (aminocyclohexyl)-alkanes having from 13 to 15 C-atoms, e g bis-( 4-aminocyclohexyl)-propane, and optionally heterocyclic diamines having from 4 to 8 Catoms, e.g piperazine.

Up to 10 mol-%, preferably up to 5 mol-%, of the isophthalic acid can be substituted by terephthalic acid without changing the properties of the 40 copolyamide substantially.

1,590,529 The molecular weight of the polyamides can be controlled by means of carboxylic acids or amines, preferably benzoic acid or sebacic acid.

The relative solution viscosity of the copolyamides according to the invention, determined on a 1 % by weight solution of the polyamide in m-cresol at 25 C in an Ubbelohde-Viskosimeter, is > 2 The copolyamides are transparent and can easily 5 be processed thermo-plastically They may contain auxiliary agents and additives, for example lubricants, mould release agents, dyes, glass fibres, fillers or flameretarding agents The copolyamides may be used for the manufacture of shaped products with improved dimensional stability at elevated temperatures and improved glass transition temperatures such as fibres, sheets, plates or injection 10 moulded articles.

Example 1 (Reference Example, according to Parent Application).

101 6 g ( 0 36 mol) of a salt of hexa-methylene diamine and isophthalic acid and 11.21 g ( 0 04 mol) of a salt of 1,4-di-amino-cyclo-hexane and isophthalic acid are heated under the addition of 0 84 g ( 2 % by weight, based on the proportion of hexa 15 methylene diamine originally put into the process) of hexa-methylene diamine under an atmosphere of nitrogen with stirring, first to 220 C for two hours and then to 270 C for three hours A transparent copolyamide is obtained It has a relative solution viscosity of 3 1, determined on a 1 % by weight solution of the polyamide in m-cresol at 25 C in an Ubbelohde-Viskosimeter 20 The glass transition temperature of this copolyamide as well as that of several other transparent copolyamides which were prepared in a similar manner but with a different molar ratio of hexa-methylene diamine to 1,4-di-amino-cyclohexane were determined by differential thermo-analysis The results are summarised in the Table below 25 Molar ratio of hexamethylene diamine:

1,4-diaminocyclohexane Glass transition temperature ( C) 100: 0 130 99: 1 132 95: 5 135 90: 10 143 85: 15 148 80:20 149 Example 2.

Comparison Example.

A mixture of the salt of isophthalic acid and hexa-methylene diamine and of the salt of terephthalic acid and hexa-methylene diamine are polycondensed as described in Example 1 The loss of diamine is compensated by the addition of 2 % by weight of hexa-methylene diamine (based on the quantity of hexamethylene diamine originally put into the process) The molecular weight is controlled by the addition of 0 5 mol of benzoic acid (based on 100 mol of salt) The following Table shows the dependence of the glass transition temperature on the ratio of isophthalic acid to terephthalic acid in the mixture.

3 1,590,529 1,590,529 Molar ratio of isophthalic acid:

terephthalic acid Glass transition temperature ( C) 60:40 133 70:30 132 75:25 132 85: 15 132 95: 5 132 Example 3 (Comparison) Transparent copolyamides of isophthalic acid, hexa-methylene diamine and bis-( 4-amino-cyclo-hexyl)-methane were prepared in a manner as described in Example 1 The molar ratio of the diamine components were varied as shown in the following Table and the corresponding glass transition temperature was determined by differential thermo-analysis.

Molar ratio of hexamethylene diamine:

bis-( 4-aminocyclohexyl)methane Glass transition temperature ( C) 95: 5 136 90:10 139 80: 20 152 70: 30 165 60: 40 176

Claims

WHAT WE CLAIM IS:-

1 Transparent copolyamides consisting essentially of from 50 to 99 9 mol % of units (A) having the structure:

It t -hn ( 50) h vngtheu 6-e and from 50 to 0 1 mol % of units (B) having the structure:

wherein R denotes (I) a bis-(aminocyclohexyl)-alkane group of the formula:

1,590,529 5 H (RI)2 H 1 NQ 9 C Nwherein one R' group denotes methyl and the other R' group denotes hydrogen or methyl, and optionally ( 2) a heterocyclic amine group of the formula:

(R 1)z 5 wherein R" denotes methyl or ethyl, the radicals R" being the same or different, and z represents 0, 1 or 2, the sum of (A) and (B) being 100 %.

2 Copolyamides as claimed in Claim 1, consisting essentially of from 60 to 90 10 mol % of units having the structure (A) and from 40 to 10 mol % of units having the structure (B).

3 Copolyamides as claimed in Claim 1, wherein R is derived from bis-( 4amino-cyclo-hexyl)-propane, and optionally piperazine.

4 A copolyamide according to claim 1, substantially as herein described 15 A process for preparing a copolyamide according to claim 1, which comiprises condensing, in the required proportions, isophthalic acid, hexamethylene diamine and a diamine corresponding to the group R, optionally in the form of their salts.

6 A process according to claim 5, wherein pre-condensation is carried out at a 20 temperature of from 190 to 230 C, and poly-condensation is completed at a temperature of from 240 to 300 C.

7 A process according to claim 5, substantially as herein described.

8 A copolyamide when prepared by a process according to any one of claims 5 to 7 25 9 Shaped articles comprising a copolyamide according to any one of claims 1 to 4 and 8.

ELKINGTON & FIFE, Chartered Patent Agents, High Holborn House, 52/54 High Holborn, London WC 1 V 65 H.

Agents for the Applicants.

Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1981.

Published by the Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.