| 摘要 |
Self-curing compositions for coating or sealing a substrate comprise together with a polymerization catalyst a monomeric mixture of (a) methyl methacrylate and optionally, at least one methacrylate ester of a C2- 4 alcohol, and (b) at least one acrylate or methacrylate ester of an alcohol having more than 4, preferably 6-10, carbon atoms, and at least one copolymer of vinyl chloride and vinyl acetate, optionally with one or more other copolymerizable monomers. The latter optional components of the copolymer include maleic acid or anhydride and esters thereof. Optional components of monomer (a) include esters of ethylene glycol, glycerine and n-butanol; suitable monomers (b) include esters of triethylene glycol, dipropylene glycol, sorbitol, and hexyl, octyl, 2-ethylhexyl, decyl and lauryl alcohols. Polymers of these monomers may also be included in the composition. In addition to the specified copolymer, polyvinyl acetate or a copolymer of vinyl chloride and a maleic ester may also be included in the composition. The catalyst preferably comprises a tertiary amine, e.g. dimethyl-p-toluidine, and a peroxide, e.g. benzoyl peroxide or p-chlorobenzoyl peroxide. It may also include a mercaptan, a -hydroxy sulphone or a heavy metal compound. Other optional components may include, e.g. stabilizers for the vinyl chloride copolymer such as fatty acid salts of Ca, Ba, Cd or Zn, and organotin compounds, U.V. stabilizers such as benzophenone or benzotriazole, fillers such as sand, crushed rock, ground asbestos, corundum, plaster of Paris, chalk, zinc white, sawdust, BaSO4, polymer powders and silicic acid, plasticizers and wax. The compositions are applied in syrupy form, the consistency of which may be adjusted by adding small quantities of solvents. |
