GB581620A - Manufacture of shaped structures from oriented halogen-containing polymers of vinyl and vinylidene compounds - Google Patents

Abstract

The heat shrinkage of a shaped object of an oriented halogen-containing vinyl or vinylidene polymer is reduced by heating the shaped object, such as a fibre, film, foil, tape or tube, in contact with a curing (insolubilizing) agent and under tension at a temperature of 135-150 DEG C. until the polymer is insoluble in solvents for the untreated polymer. Where the softening point of the shaped object before treatment is below 135 DEG C., the fibre or other shaped object is heated under tension at a temperature close to, but below, the softening point of the polymer, and the temperature is raised, but always below the then softening point of the polymer, to 135-150 DEG C. and maintained until the polymer is insoluble in solvents for the untreated polymer. The curing agent may be added to the solution of the polymer intended for wet or dry spinning, and the spun filaments are wound on a bobbin so that they cannot retract, and then heat treated. The heat treatment is preferably performed in a high boiling liquid which has no solvent or swelling action on the filaments, e.g., kerosene, mineral oil, or glycerol. Alternatively, the curing agent may be added to the high boiling liquid. The following halogen-containing vinyl or vinylidene polymers are mentioned as examples; polyvinyl chloride; polyvinyl bromide; polyvinyl fluoride prepared by polymerizing vinyl fluoride in the presence of an organic peroxy compound; poly-1 : 1-fluorobromoethylene; chlorinated polyethylene; after-chlorinated polyvinyl chloride; vinyl chloride/diethyl fumarate polymers; vinyl chloride/vinyl ester polymers; vinyl fluoride/olefinic hydrocarbon polymers; vinyl chloride/ethylene polymers; polyvinylidene chloride; polyvinylidene bromide; polyvinylidene fluoride; interpolymers of vinylidene fluoride with ethylene and halogenated ethylenes; vinylidene chloride/vinyl chloride copolymers; vinylidene chloride/acrylonitrile; and copolymers of vinylidene chloride with unsaturated polymerizable ketones. The polymer may contain stabilizers such as phenyl glycide ether and stearylamine, plasticizers, delustrants, fillers and the like. The following curing agents are specified; butyraldehydeaniline condensation product; di-cyclo-pentamethylenethiuram tetrasulphide; aliphatic aldehyde-aromatic amine products; sodium sulphide or potassium sulphide; urea and N-alkylureas; thioureas, e.g., di-o-tolylthiourea; dithiocarbamic acids, e.g., pentamethylene dithiocarbamic acid; thiuram sulphides, e.g., didimethylthiuram monosulphide and diethylthiuram disulphide; mercaptothiazoles, e.g., mercaptobenzothiazoles and zinc mercaptothiazole; xanthates, e.g., zinc butyl xanthate; guanidines, e.g., diphenylguanidine, the guanidine salt of dimethylamino dimethyldithiocarbamic acid, and guanidine hydrochloride; inorganic materials such as zinc oxide, magnesia, zinc dust, sulphuric acid and sulphur. The following examples are given. (1) A solution of a copolymer of vinyl chloride and diethyl fumarate containing magnesium oxide and a condensation product of butyraldehyde and aniline (Accelerator 808) is wet spun and the filaments after soaking in water are stretched in boiling water. The oriented filaments are then heated at constant length for 3 hours at 100 DEG C., 1.5 hours at 125 DEG C. and 0.8 hour at 150 DEG C. (2) A solution of a similar copolymer containing phenyl glycide ether stabilizer, magnesium oxide and Accelerator 808 is wet spun and the filaments stretched in boiling water. They are then heated at constant length in stages rising to 145 DEG C. (3) Oriented fibres obtained by wet spinning a solution of polyvinylidene fluoride and stretching, are heated at constant length at 150 DEG C. for 0.5 hour in a solution of Accelerator 808 in mineral oil. (4) Oriented fibres of chlorinated polyvinyl chloride are held at constant length in a solution of Accelerator 808 in kerosene, and heated slowly to 145-150 DEG C. (5) Oriented fibres of a copolymer of vinylidene chloride and vinyl chloride are treated as in Example (4). (5) The untreated fibres of Example (4) are held at constant length in a solution of dicyclopentamethylenethiuram tetrasulphide in kerosene and heated to 135 DEG C.