Copolyamides and polyamide compositions, process of manufacture and applications

Abstract

Colpolyamides resulting from the polycondensation of a mixture of (a) dodecanelactam (L12) or of 12-aminododecanoic acid (A12) and of (b) 11-aminoundecanoic acid (A11) are characterized in that the monomer L12 or A12 represents 1 to 15% or 85 to 99% by weight of the mixture, and the copolyamides have melting points (mp) as a function of the composition, the units originating from the monomer A12 and L12 being in a majority or minority respectively: (1) A12 or L12 is a majority: mp (.degree. C.).gtoreq.176-0.567.times.(% A11) (2) A12 or L12 is a majority: mp (.degree.).gtoreq.187-0.5.times.(% A12 or L12), the melting points being determined by taking the peaks of the exotherm signals obtained in differential thermal analysis with a rate of heating of 10.degree. C./minute for the second heating run. Such copolyamides have a property of resilience at low temperature and a property of improved suppleness, especially when plasticizer is added to them. Their ductile/brittle transition temperature is shifted towards a lower temperature.

Dependencies are inferred from the claim text.