Epoxy resin mixts. with improved rheological properties - contain polyfunctional epoxide(s), nitrogen-contg. hardener, resin-soluble thermoplastic or rubber, and microfine silica

摘要

Resin mixts. (I) contain (A) 100 pts.wt. polyfunctional epoxy cpd(s)., (B) 2-206 pts.wt. N-contg. hardener, (C) 3-30 pts.wt. thermoplastic or rubber which is soluble in (A), and (D) 0.3-10 pts.wt. finely divided silica. Pref., (B) is an aromatic diamine or dicyandiamide and thermoplastic (C) is a polyether-sulphone; (D) has specific surface (BET) 50-500 m2/g and particle size 5-50 nm, and is pref. hydrophilic silica. Pref., (A) are diglycidyl ethers of Bisphenol A, Bisphenol F or dicyclopentadienylphenol (e.g., DER 332, Epikote 828, Araldite PY 306, Tactix 556, etc. (RTM)), Araldite MY 721 (RTM: tetraglycidyldiaminodiphenylmethane), triglycidyl-p-amino-phenol or triglycidyltriphenylmethane). (B) is, e.g., 4,4'-diamino-diphenylsulphone (DDS) or dicyandiamide, (C) is polyether-sulphone, (D) is Cab-O-Sil M5 or Aerosil 200 (RTM). USE/ADVANTAGE - Epoxy resin mixts. are used for the prodn. of prepregs for fibre-reinforced composites. Mixts. have improved rheological properties, i.e., relatively constant high viscosity under curing conditions (so that the resin does not run out) combined with a sufficiently low viscosity for the impregnation stage.