| 摘要 |
<p>This composite material comprises an epoxy resin, cured with dicyandiamide and/or a urea deriv. and reinforcing fibres. Finely dispersed in the epoxy resin are polyvinyl formal particles having an ave. size of not more than 5 microns. The reinforcing fibres are e.g. carbon fibres, aromatic gp. polyamide fibres, glass fibres etc. The prepreg is produced by blending a specified resin composite with reinforcing fibres using hot rolling etc. An example of a specified resin composite is one obtd. by melt mixing an epoxy resin composite (1) (100 pts. by wt.), polyvinyl formal resin (2) (1-30 pts. by wt.), and the curing agent dicyandiamide and/or urea derivs. The epoxy resin composite (1) comprises a bisphenol type epoxy resin having a mean mol. number of 400 or more (10-40 pts. by wt.), and a phenolnoborac (or its deriv.) epoxy resin (20-45 pts. by wt.). The polyvinylformal resin contains 60% or more vinyl formal, vinyl acetate and vinyl alcohol. Its mean deg. of polymerisation must be 100 or less.</p> |
