Curable compositions based on epoxy resins

Abstract

A solvent-free curable composition has a long shelf life and consists of A 100 parts by weight of an epoxy resin and B from 10 to 100 parts by weight of .[.,.]. .Iadd.4,4-bis-(para-aminobenzoyl)-piperazine .Iaddend.as a curing agent for the epoxy resin, .[.an aromatic diamine containing ##STR1## groups,.]. with or without C from 0.01 to 5 parts by weight of an accelerator, the curing agent for the epoxy resin being finely dispersed in the latter and preferably having a particle size of less than 10 μm. .[.The preferred epoxy resin curing agent is 4,4'-diaminodiphenyl ketone..]. The curable composition is used in particular for the preparation of fiber-reinforced materials.

We claim: 
     
       1. An essentially solvent-free curable composition which has a long shelf life and consists of A 100 parts by weight of an epoxy resin and   B from 10 to 100 parts by weight of, .Iadd.N,N'-bis-(para-aminobenzoyl)-piperazine .Iaddend.as a curing agent for the epoxy resin, .[.an aromatic diamine containing ##STR6## groups,.]. with or without C from 0.01 to 5 parts by weight of an accelerator, wherein the curing agent for the epoxy resin is finely dispersed in the latter.   
     
     
       2. A curable composition as claimed in claim 1, wherein not less than 90% by volume of the particles of the curing agent for the epoxy resin have a particle size of less than 10 um. .[.3. A curable composition as claimed in claim 1, wherein the epoxy resin curing agent used is a diamine of the formula ##STR7## 
     
     
         .[.4.  A curable composition as claimed in claim 1, wherein the epoxy 
     
     
        resin curing agent used is 4,4'-diaminodiphenyl ketone..]. 5. A process for the preparation of a fiber-reinforced material by impregnation of from 70 to 30% by volume of reinforcing fibers with from 30 to 70% by volume of a curable composition as claimed in claim 1.