GB886897A - Dynamic curing techniques - Google Patents

Abstract

A process for curing polyethylene comprises blending polyethylene with a peroxide curing agent and heating the blend to curing temperature under conditions of continuous mixing until curing is effected. The polyethylene may be a linear high density polyethylene. Specified peroxides are dicumyl peroxide, peracetic acid, acetyl benzoyl peroxide, hydroxyheptyl peroxide, isopropyl percarbonate, methyl ethyl ketone peroxide, cyclohexanone peroxide, cyclohexyl hydroperoxide, 2,4-dichlorobenzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, methyl amyl ketone peroxide, acetyl peroxide, lauroyl peroxide, benzoyl peroxide, methylcyclo hydroperoxide, t-butyl permaleic acid, t-butyl perbenzoate, di-t-butyl diperphthalate, t-butyl perphthalic acid, p-chlorobenzoyl peroxide, t-butyl peracetate, di-t-butyl peroxide, dibenzoyl diperoxide, lead peroxide and potassium persulphate. The blends may also contain fillers, e.g. carbon blacks, silica and mica; rubber accelerators, e.g. tetramethyl thiuram disulphide, benzothiazyl disulphide, 2-mercaptobenzothiazole, N-cyclohexylbenzothiazole-2-sulphenamide, selenium diethyl dithiocarbamate disulphide and zinc butylxanthate; antioxidants, e.g. phenyl-b -naphthylamine, N,N1-di-b -naphthyl-p-phenylene diamines, aldol-a -naphthylamine, 2, 2, 4-trimethyl-1, 2-dihydroquinoline, hydroquinone monobenzyl ether and 2, 21-methylene-bis(4-methyl-6-tert. butyl phenol); and oils, e.g. derived from coal tar, pine tar or petroleum. The products may be extruded or moulded, e.g. in the manufacture of pipes, wire coatings and plastic bottles.