GB1250877A - - Google Patents

Abstract

1,250,877. Copolyamides. B.P. CHEMICALS (UK) Ltd. 15 Nov., 1968 [9 Dec., 1907], No. 56095/67. Heading C3R. At least 80 mol. per cent of the units of a copolyamide are derivable from (a) 6-aminohexanoic acid (b) m- or m/p-xylylene diamine containing not more than 30% p-isomer and (c) an aromatic or araliphatic dicarboxylic acid. The selection of the particular combination of (a), (b) and (c) is stated to give transparent amorphous polyamides of advantageous tensile strength. (c) may be one or more of iso- and tere-phthalic acids and phenylene diacetic acid. Optional comonomers mentioned are laurolactam or 12-aminododecanoic acid; adipic, azelaic, sebacic or dodecanedioic acid; and 2,2,4- or 2,4,4-trimethyl hexamethylene diamine or 3-aminomethyl-3,5,5-trimethyl cyclohexylamine. The components may be meltcondensed directly or with a precondensation step in the presence of 20 to 150 wt. of water under reflux conditions; alternatively an intermediate amide may be prepared by (b) or (c) with (a) at 200‹ to 250‹ C. in the presence of a catalyst before reaction with the remaining component(s). The process may be continuous. Monobasic acids or monoamines may be used as viscosity stabilizers with precautions to avoid discolouration. A colour stabilizer such as an inorganic, e.g. NH 4 , hypophosphite or a trihydrocarbyl phosphite may be added as may heat, oxidation and U.V. stabilizers. The polymers may have an inherent viscosity (0.15% solution in H 2 SO 4 at 25‹ C.) above 0.7. In examples the physical properties of copolymers of the invention wherein (c) is iso- and/or terephthalated acid are compared with those of nylons 6, 12 and 66. In some examples, the polymer is insoluble in H 2 SO 4 . The copolymer is stated to be suitable for various moulding techniques; coating, especially on metals, being applied as a powder with subsequent heating to form a coherent film; rigid foams; and fibres. Reference is made to Specifications 1,250,878 and 1,049,987.