Epoxy two-part formulations
The invention relates to resin compositions for epoxy adhesives, comprising a di-functional aromatic epoxy compound. The resin compositions and/or uncured adhesive compositions having low viscosity at low temperatures. Adhesives made therefrom have good strength and bulk properties. The invention includes methods of making and using the compositions, as well as adhesives made from the compositions.
1. A resin composition for a two-part adhesive comprising
a) an epoxy compound having the formula
wherein each R′ is independently hydrogen, methyl, ethyl, n-propyl or isopropyl;
b) a polyurethane comprising an elastomeric portion including one or more soft segments selected from a polyether, a polybutadiene or polyester soft segment, the soft segment or segments each having a molecular weight of 1000 to 10,000 daltons, the polyurethane having an average of 2 to 4 isocyanate groups capped with a polyphenol;
c) a core shell rubber epoxy dispersion comprising core shell rubber particles having a rubbery core with a T g of less than −25° C. and a shell polymer polymerized from at least one lower alkyl methacrylate provided that up to 40% of the weight of the shell polymer can be formed from styrene, vinyl acetate, vinyl chloride, methyl acrylate, ethyl acrylate and butyl acrylate; wherein the core shell rubber particles are dispersed in an epoxy resin and
d) an alkyl diglycidyl ether comprising a linear C 3-10 linear alkyl group that is glycidyl terminated.
2. The resin composition of claim 1 , wherein the alkyl diglycidyl ether comprises 1,6-hexanediol diglycidyl ether.