GB963575A - A method of producing single or multilayer bodies of fibrous material containing synthetic resins - Google Patents

Abstract

Curable prepolymers are prepared from dialkyl phthalate and other vinyl monomers. For Example 1, dibenzoyl peroxide paste is dissolved in a mixture of dialkyl phthalate, carbon tetrachloride and methyl methacrylate. This mixture is then run into a solution of polyvinyl alcohol, a copolymer of maleic anhydride and vinyl methyl ether and potassium stearate in water, while stirring. The emulsion is heated in a nitrogen atmosphere for 1/2 hour, tert-butyl perbenzoate added and polymerization continued until it is sufficiently advanced, as indicated by the refractive index of the product, when the reaction is stopped by cooling. In Example 2, dibenzoyl peroxide paste is dissolved in a mixture of dialkyl phthalate and methyl methacrylate. This solution is then run into an aqueous solution of polyacrylic acid and polyvinyl alcohol, while stirring. A solution of stearic acid in hexanone is added. This emulsion is then polymerized as in Example 1.ALSO:Paper containing a synthetic resin is made by adding an aqueous preparation of a curable prepolymer of diallyl phthalate to a pulp of the fibrous material, and then forming the pulp, e.g. on a paper-making machine, to form a body containing 20 to 70% by weight of resin. The prepolymer may be a copolymer with, e.g., esters of acrylic acid of their derivatives. It may be in the form of a suspension or emulsion, which may be stablized by surface-active substances or protective colloids, e.g. alkylaryl sulphonates, alkyl sulphates, copolymers of maleic anhydride with other vinyl compounds such as vinyl methyl ether, polymers of methacrylic acid and its copolymers with acrylamide. Thickeners, e.g. methyl-cullulose or polyvinyl alcohol may also be used. Precipitants such as aluminium formate or sulphate or quaternary nitrogen compounds produced from dicyandiamide may be added to the pulp after the prepolymer. A filler of large surface area, e.g. fumed silica or a silicate, may also be added. Fillers used in the examples are: (1) TiO2 and calcium-aluminium silicate; and (2) chromium oxide and aluminium silicate. The paper may be compounded during production by the duplex or multiplex process, the web in the middle may then have a higher resin content than the webs on the outside.