GB785032A - Self-hardening surface coating compositions - Google Patents

Abstract

A self-hardening surface coating composition for copper, zinc or their alloys comprises a mixture of at least one monomeric polymerizable compound having at least one carbon-to-carbon double bond, e.g. styrene and methyl methacrylate, a polymerization catalyst and a small amount of hydroxyquinoline or an enolisable acetone derivative, for example acetyl or benzoyl acetone. The composition may also include at least one wholly or partially polymerized compound, e.g. polystyrene; one or more a ,b -unsaturated polyester resins, e.g. maleic acid-glycol and/or maleic anhydride; small amounts of acrylic and methacrylic acids or amides or their polymers; plasticizing compounds such as decalol vinyl ether and higher esters of acrylic and methacrylic acids, e.g. acrylic acid butyl ester and polyvinyl methyl and ethyl ethers; cross-linking agents such as divinyl benzene and hardening monomers, e.g. methyl methacrylate and p-dichlorostyrene. The catalyst may be a t-amine, e.g. di-ethanol-p-toluidine, a -amino- and a -hydroxy-sulphones and/or benzoyl peroxide, and small quantities of accelerators such as labile halogen-containing compounds, mono- and di-hydric alcohols, and heavy metal salts may be present. Pigments, fillers, e.g. pyrogenically prepared silicon dioxide, resins, cellulose compounds, plasticisers and/or oils may also be present. The reacting substances, such as the polymerization components and the catalyst, are preferably combined at, or shortly before application, e.g. from separate containers in a spray gun or from separate tubes; and the catalyst may be in solution or a suspension which may be thickened for example with pyrogenically prepared silicon dioxide. In examples, brass surfaces are bonded (1) with the component systems (a) mono- and polystyrene, maleic acid-glycol polyester, acrylic acid, diethanol-p-toluidine, acetyl acetone and a hydroquinone stabilizer and (b) as (a) but with benzoyl peroxide replacing the acrylic acid, which are applied to the separate surfaces which are then brought into contact; (2) (a) as above but without acetyl acetone and (b) polystyrene beads, quartz powder, hydroxy-quinoline and benzoyl peroxide; and (3) (a) as in (1) and (b) dioctyl phthalate, benzoyl peroxide and pyrogenically prepared silicon dioxide. The compositions in (2) and (3) are mixed just before use and applied to one of the surfaces to be adhered.