GB584857A - Improvements in bonding surfaces - Google Patents

Abstract

A liquid, dough or jelly-like composition for bonding two surfaces together consists of a mixture containing from 1 to 30 per cent by weight of monomeric acrylic and/or methacrylic acid and/or the anhydride or anhydrides thereof, the other constituent(s) being one or more butyl methacrylates and, if desired, up to 25 per cent by weight of the composition of any other unsaturated organic compound(s) which contain the group CH2=C< and are dissolved in the other monomeric constituents, and/or one or more polymers or interpolymers of the butyl methacrylates, said interpolymers containing, if desired, up to 25 per cent of their weight of molecular units derived from one or more unsaturated organic compounds containing the group >C=C< other than a butyl methacrylate and said interpolymers being soluble in said monomeric constituents. The bonding is effected by applying the composition to one or both surfaces, then either assembling the surfaces together and subjecting the composition to polymerizing conditions until it is converted to a solid at room temperature, or polymerizing the composition until it is solid at room temperature and assembling the surfaces together when at least one of the said films or layers is heated, or softened by a liquid to a sticky condition. The preferred average molecular weight of the polymer or interpolymer is between 20,000 and 40,000 and the preferred composition contains from 40 to 50 per cent by weight of polymer or interpolymer. The composition should preferably have as acid constituent between 8 to 12 per cent by weight methacrylic acid. The composition may consist essentially of n-butyl methacrylate or sec-butyl methacrylate and acrylic and/or methacrylic acid, and may contain a polymerization catalyst such as benzoyl peroxide, benzoin and uranyl acetate or nitrate and a polymerization inhibitor such as hydroquinone. The polymerization may take place at atmospheric or slightly elevated pressure and at a temperature not greater than 120 DEG C. The compositions may contain a minor proportion of an unsaturated organic compound containing more than one CH2=C< group, e.g. allyl methacrylate and diallyl fumarate. The compositions may be used to bond surfaces such as mild steel, aluminium alloys, brass, phenol formaldehyde resin compositions, glass, polymethylmethacrylate and wood. Specifications 371,396, 426,265, [Group V], 427,494, 475,570, 478,323, 517,123, 569,684, 570,837 and 582,559 are referred to.