Hot-curing epoxy resin compositions that can be used as bodyshell adhesive or structural foam

Abstract

A hot-curing epoxy resin composition including: at least one liquid epoxy resin having an average of more than one epoxy group per molecule; at least one solid epoxy resin having an average of more than one epoxy group per molecule; at least one polymeric impact modifier comprising a functionalized, epoxy-terminated, acrylonitrile/butadiene copolymer; at least one homopolymer, solid at room temperature, of an olefinically unsaturated monomer; and at least one epoxy-resin hardener which is activated via an elevated temperature, with a proportion by weight of the polymeric impact modifier, based on the epoxy resin composition, being smaller than 20% by weight, and an amount by weight of the homopolymer, solid at room temperature, being greater than the amount by weight of the polymeric impact modifier.

1 . A hot-curing epoxy resin composition comprising:
 at least one liquid epoxy resin having an average of more than one epoxy group per molecule;   at least one solid epoxy resin having an average of more than one epoxy group per molecule;   at least one polymeric impact modifier comprising a functionalized, epoxy-terminated, acrylonitrile/butadiene copolymer;   at least one homopolymer, solid at room temperature, of an olefinically unsaturated monomer; and   at least one epoxy-resin hardener which is activated via an elevated temperature,   with a proportion by weight of the polymeric impact modifier, based on the epoxy resin composition, being smaller than 20% by weight, and an amount by weight of the homopolymer, solid at room temperature, being greater than the amount by weight of the polymeric impact modifier.   
     
     
         2 . The hot-curing epoxy resin composition according to  claim 1 , comprising:
 at least one physical or chemical blowing agent, in an amount from 0.1 to 3% by weight of the composition.   
     
     
         3 . The hot-curing epoxy resin composition according to  claim 1 , wherein the homopolymer is a homopolymer of a monomer selected from the group consisting of acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, and styrene. 
     
     
         4 . The hot-curing epoxy resin composition according to  claim 1 , wherein the hardener is a hardener selected from the group consisting of dicyandiamide, guanamines, guanidines, aminoguanidines and their derivatives, substituted ureas, phenyldimethylureas, imidazoles, imidazole salts, imidazolines and amine complexes. 
     
     
         5 . The hot-curing epoxy resin composition according to  claim 1 , wherein a value of a ratio by weight of liquid epoxy resin to solid epoxy resin is from 0.2 to 5. 
     
     
         6 . The hot-curing epoxy resin composition according to  claim 1 , wherein a glass transition temperature of the at least one homopolymer, solid at room temperature, is above 100° C. 
     
     
         7 . The hot-curing epoxy resin composition according to  claim 1 , in combination with a reinforcement element for reinforcement of metallic structures having a support. 
     
     
         8 . The hot-curing epoxy resin composition according to  claim 1 , wherein a value of a ratio by weight of the liquid epoxy resin to the solid epoxy resin is from 1 to 1.5. 
     
     
         9 . The hot-curing epoxy resin composition according to  claim 1 , wherein the homopolymer is a homopolymer of a monomer selected from the group consisting of methyl(meth)acrylate and styrene. 
     
     
         10 . The hot-curing epoxy resin composition according to  claim 1 , wherein the hardener is a hardener selected from the group consisting of 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, p-chlorophenyl-N,N-dimethylurea, 3-phenyl-1,1-dimethylurea, 3,4-dichlorophenyl-N,N-dimethylurea, N,N-dimethylurea, N-isobutyl-N′,N′-dimethylurea, and 1,1′-(hexane-1,6-diyl)bis(3,3′-dimethylurea). 
     
     
         11 . A structural foam obtained by a process comprising heating the hot-curing epoxy resin composition according to  claim 1 . 
     
     
         12 . A hardened epoxy resin composition obtained by a process comprising heating the hot-curing epoxy resin composition according to  claim 1  to a temperature of from 100 to 220° C. 
     
     
         13 . A process for the adhesive bonding of heat-resistant carriers, comprising:
 i) applying the hot-curing epoxy resin composition according to  claim 1  to a surface of a heat-resistant carrier metal;   ii) contacting the applied hot-curing epoxy resin composition with the surface of a further heat-resistant carrier formed of metal; and   iii) heating of the hot-curing epoxy resin composition to a temperature of from 100 to 220° C.   
     
     
         14 . The process according to  claim 13 , wherein the applying includes applying the epoxy resin composition for bonding or reinforcement of metal structures, or reinforcing filling of cavities in vehicle construction or sandwich-panel construction. 
     
     
         15 . The process according to  claim 13 , wherein the heating is to a temperature of from 120 to 200° C. 
     
     
         16 . The process according to  claim 13 , wherein the heating is to a temperature of from 160 to 190° C.