GB787022A - Improvements in or relating to self-hardening, liquid resinous compositions and articles having the resinous composition bonded thereto - Google Patents

Abstract

A self-hardening liquid composition contains a liquid to semi-solid epoxide resin and a liquid aliphatic polythiopolymercaptan, the mixture containing sufficient epoxide resin to yield a self-hardening composition and, in any case, not less than 0.5 epoxy groups per thiol group. It is useful for forming tough rubbery coatings, e.g. on aluminium or paper. Suitable polythiopolymercaptans are "Thiokol" (Registered Trade Mark) LP2, 3, 8 or 32 polymers which may be made by condensation of dichloroethyl formal containing a small proportion of trichloropropane with sodium polysulphide followed by reductive cleavage of disulphide groups to yield free -SH groups. Dichlorodiethyl ether or ethylene dichloride may be used instead of the dichloroethyl formal. The preferred epoxy resin is "Epon" (Registered Trade Mark) 562 prepared from glycerol and epichlorhydrin, followed by treatment to eliminate HCl. Metal oxide curing agents, e.g. oxides of lead or zinc, fillers, e.g. carbon black, ZnS, BaSO4, CaCO3, TiO2, micalith, asbestos, and other synthetic resins may be incorporated. Volatile liquid diluents to produce solutions or dispersions may also be used. In the examples: (1) "Epon" 562 and "Thiokol" LP2 are mixed and various proportions poured on to aluminium panels and allowed to set for 16-24 hours at 70-80 DEG F. In Example (2) carbon black pigment, lead peroxide curing agent, and stearic acid to lengthen the pot life were included. In Example (3) carbon black, liquid phenol-aldehyde resin and red lead were added to the main ingredients of the mixture. Example (4) uses a semi-solid epoxy resin from epichlorhydrin and 2,2-bis-(4-hydroxyphenyl) propane together with "Epon" 562 and "Thiokol" LP2 and Example (5) uses a mixture of "Epon" 562 and "Thiokol" LP8. Reference has been directed by the Comptroller to Specifications 730,670 and 755,944.