| 摘要 |
Polymers of at least 75 weight per cent of vinyl chloride are halogenated by reacting a macrogranular vinyl chloride polymer having a specific viscosity of at least 0.40 suspended in an aqueous liquid in the presence of a chlorohydrocarbon swelling agent, illumination and a a catalytic amount of a reducing agent selected from alkali metal sulphites, metabisulphites, bisulphites and hydrosulphites, metal sulphoxylates of C1- 8 aldehydes, C1- 10 aldehydes or dialdehydes, and reducing sugars, at a temperature no greater than 65 DEG C. Specified resins are polyvinyl chloride and copolymers of vinyl chloride with vinylidene chloride, vinyl acetate, isopropenyl acetate, methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, styrene, a methyl styrene, ethylene, propylene, methyl methacrylate, ethyl methacrylate, acrylonitrile, maleic esters and fumaric esters. The resins are preferably porous with a pore space of 5 to 50% by volume. Specified swelling agents are mono-, di- and trichloromethane. Many suitable reducing agents are listed. Examples describe the chlorination of polyvinyl chloride in aqueous suspension in the presence of chloroform and (1) sodium formaldehyde sulphoxylate; (2) sodium sulphite, sodium metabisulphite, sodium bisulphite, sodium hydrosulphite, sodium thiosulphate, sodium formaldehyde sulphoxylate and ammonium sulphite; and (3) acetaldehyde, benzaldehyde, formaldehyde trimer, maltose and dextrose. Specifications 548,486 and 949,895 are referred to.
|
