Improvements in or relating to the production of filaments, films and the like from vinyl resins

Abstract

Abstract Filaments, films, and the like are produced by subjecting a shaped stream of a vinyl resin solution to partial precipitation in a liquid which is a non-solvent for the vinyl resin and is at least partially miscible with the solvent in said solution, and thereafter subjecting the shaped stream to heat to remove remaining solvent and non-solvent. The precipitating bath which preferably contains at least about 25 per cent of water may be employed at a temperature between 25 and 35 DEG C. During the drying of the filaments, films, or the like, they are preferably supported on surfaces lubricated with an alcohol or alcoholic composition, e.g., at least one alcohol consisting of ethylene glycol, polyethylene glycols, propylene glycol, polypropylene glycols, or glycerine, together with a monohydric alcohol such as butyl, amyl, hexyl, or octyl alcohol. Suitable vinyl resins are vinyl chloride, acetate, or propionate, or styrene, but preferably there are used resins made by conjointly polymerizing two or more vinyl derivatives, e.g., vinyl chloride and vinyl acetate in the proportions of about 70-93 of the chloride to 30-7 of the acetate. In an example, a resin obtained by polymerizing a mixture of vinyl chloride and vinyl acetate in the presence of benzoyl acetyl peroxide, is dissolved in acetone and extruded by pneumatic pressure through a slit into water at 35 DEG C. As soon as the film is coherent and strong enough for handling, it is dried at a temperature of 50--60 DEG C. Other solvents specified are methyl ethyl ketone, dipropyl ketone, cyclohexanone, methyl butyl ketone, 1, 4-dioxane, dimethyl dioxane, ethyl acetate, butyl acetate, chlorbenzene, ethylene and propylene di-chlorides or di-bromides, acetylene tetrachloride, toluene, and xylene. Suitable non-solvents for precipitating are water, pentane, hexane, heptane, methanol, ethanol, isopropanol, ethylene glycol, and diethyl, di-isopropyl and dibutyl ethers. The vinyl resin solution may contain plasticizers such as di(ethylene glycol monobutyl ether) phthalate, di(b -butoxy ethyl) phthalate, tricresyl phosphate, chlorinated naphthalenes, and diphenyl derivatives, and also a wax, such as paraffin wax, a dye, pigment, or the like.

Inventors

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