Multilayer board with honeycomb core and thermoset adhesive layers - has outer layers of partly crystalline thermoplastic activated by corona treatment or application of amorphous thermoplastic

摘要

A process for the prodn. of multilayer boards (I) involves pressing together (A) a core layer, (B) outer layer(s) of partly crystalline, opt. reinforced thermoplastic and (C) layer(s) or thermosetting adhesive; the novelty is that layers (B) are pre-activated on the side facing (C) by (a) corona treatment of (b) applying a layer of amorphous thermoplastic. (A) consists of plastic-coated paper with a honeycomb structure, (B) is fibre- reinforced polyether-ketone (PEK) or polyether-sulphone (PES) and (C) is epoxy resin; (B) is activated by irradiation with electrons at 10-50 kV or by co-consolidation with PES film. Pref., (A) is a honeycomb core 3-100 mm thick, made of Nomex paper (RTM: plastic coated paper); (B) is 0.1-10 mm thick, reinforced with 40-70 vol.% glass, carbon or aramid fibre, and is activated by irradiation for 0.1-10 secs. with electrons at 20-30 kV or by hot-pressing at 5-25 bar with PES film etc.; layers are laminated for 20-1000 mins. in a press at 100-250 deg.C and up to 10 bar. USE/ADVANTAGE - (I) are useful for the prodn. of aircraft parts, railway coach walls and sports equipment, e.g. surf boards. Activation of partly crystalline thermoplastic (B) enables good bonding with honeycomb core (A) by means of thermosetting adhesive (