Thermoplastic thermoformable composites

摘要

Dimensionally-stable, low-shrinkage, thermoplastically-formable fibre-reinforced composites with a polyamide-12 matrix are claimed, the matrix consisting of anionically-polymerised laurolactam contg. up to 15 wt.% 4-9C lactam comonomer and opt. also contg. conventional additives. Claimed prodn. is by: (i) soaking or impregnating the fibre reinforcement with an activated, anionic lactam-12 melt and commencing polymerisation at such a temp. that the lactam melt converts directly to polymer melt; (ii) completing polymerisation opt. under pressure; and opt. also (iii) post-forming the prod. under pressure and temp. In step (i) a solid fine powder of lactam-12, activator and catalyst can be melted on the fibre reinforcement. Pref. the fibres are endless and form 25-60 (esp. 45-55) vol.% of the composite. The temp. during contact of the melt with the reinforcement is kept below 300 degrees C and a protective gas (esp. dry N2) is present.