Abstract:
Process for the polymerization of vinyl chloride in the absence of solvents or dispersing agents in two stages. In the first stage the liquid monomers are polymerized to a conversion of from 1 to 15 percent; in the second stage polymerization is continued in the powder phase in the absence of liquid vinyl chloride. The process may be carried out continuously and gives very pure polymers which may be used for all purposes for which polyvinyl chloride is usually employed.
Abstract:
Continuous production of styrene polymers which contain an expanding agent and which are in the form of granules by extrusion of a mixture of a melt of the polymer with the expanding agent and rapid cooling of the extruded mixture, wherein excess expanding agent is first mixed with the melt and then the excess of expanding agent is evaporated. In this way both the production of a homogeneous mixture and the cooling of the mixture prior to extrusion to temperatures just above the softening point of the mixture are facilitated.
Abstract:
Molding material comprising (a) a specially selected bitumen left as a residue in the distillation of petroleum which has been deacidified with calcium hydroxide and (b) an olefin polymer. The molding material may be pigment-colored and is used in the form of sheeting for insulation in construction.
Abstract:
A process for the chlorination of vinyl chloride polymers in which a powdered vinyl chloride polymer is treated in a first stage with gaseous chlorine at below the softening point and under the action of light followed by a second stage in which it is treated at above the softening point while excluding light. The products are homogeneously chlorinated and have a high thermostability; they may be used as special glasses and for hot water pipes.