| 摘要 |
Ethylene/vinyl chloride copolymers are crosslinked by subjecting to a curing treatment in the presence of sulphur as curing agent and as stabilizer a polyol, phenol, bisphenol, urea, thiourea, dimethylol urea or epoxy compound. The copolymers may contain up to 15 weight per cent of other monomers. The curing agent may be provided by elementary sulphur or a sulphur liberating compound such as bis(dimethylthiocarbamoyl) disulphide and tetrasulphide and homologues thereof, dipentamethylene tetrasulphide, 4,41-dithiodimorpholine, alkyl phenol sulphides, sulphur chloride, hydrogen sulphide and sulphur thiocyanate. Accelerators, e.g. 2-mercaptobenzothiazole, 2,21-dithiobenzothiazole, N - cyclohexyl - 2 - benzothiazolesulphenamide, zinc dimethyl dithiocarbamate, zinc diethyl dithiocarbamate, tetramethylthiuram disulphide, 1,3-diphenyl guanidine, butyraldehyde-aniline condensates, tellurium diethyl dithiocarbamate and selenium diethyl dithiocarbamate; and activators, e.g. stearic acid, antimony sulphide, caprylic acid, coconut fatty acids, diethanolamine, hydroxystearic acid basic lead carbonate, lead salicylate, oleic acid, p-quinone dioxime, ricinoleic acid, tetrachlorobenzoquinone, zinc palmitate, zinc stearate, lead carbonate, lead oxide or magnesium oxide may be present. The polymers may be in the form of compositions with plasticizers, e.g. esters of phthalic, adipic, azelaic, oleic, fumaric and phosphoric acids; palm, rape, olive, linseed, castor, soya bean and tung oils; mineral rubbers; petroleum residues; asphalts; pine tar; paraffin wax; mineral and coal tar oils; naphthalenes; rosin; wool grease; carnauba and ceresin waxes; glycerol esters; coumarone, styrene and phenol/ formaldehyde resins; polyphenyls and chlorinated plyphenyls; chlorinated polyethylene and butyl rubber; and fillers, e.g. carbon black, wood flour, shell flour, cotton flock, sisal, chopped paper, macerated fabrics, synthetic fibres, keratin, lignin, soya bean meal, asbestos, mica, quartz, limestone, silica, clays, diatomaceous earth, fibrous glass, carborundum calcium carbonate, calcium silicate, alumina, zinc oxide, barium sulphate, titanium dioxide, talc, cork, iron oxide and zinc sulphide. The crosslinked polymers may be used for moulding and in coatings and adhesives. |
