Patent GB-923458-A (GB)
Title: Expanded materials based on vinyl chloride polymers and copolymers
IPC: C08J9/06
Filed: 1961-05-19
Abstract: Cellular moulded elements are prepared by processing vinyl chloride plastigels-containing a chemically decomposable blowing agent-without decomposition of the blowing agent to form rough shaped elements which are introduced into pressure containers larger than the dimensions of the elements and independent of the shape of the moulded elements to be produced; filling the pressure containers with gas under pressure; heating the containers to gelatinizing temperature whereby the blowing agent decomposes and the gases formed are dissolved in the composition of the rough shaped elements without causing expansion; cooling, while maintaining the gas pressure, to the plastic condition below the gelatinizing temperature; lowering the gas pressure to atmospheric pressure at which the rough-shaped elements expand while substantially maintaining their dimensional proportions without filling the pressure mould; and removing the warm moulded elements thus obtained from the pressure containers. Specified are polymers polyvinyl chloride and copolymers of vinyl chloride with vinyl acetate or vinylidene chloride stiffening gelatinizing elements aluminium laurate, aluminium stearate, magnesium stearate, calcium carbonate, calcium silicate, colloidal silica, copper phthalocyanine, lead carbonate, organic Montmorillonite derivatives and chemically pure silicic acid in submicroscopically fine division plasticizers dioctyl phthalate, tricresyl phosphate, alkali sebacate, butyl sebacate and esters of polyhydric alcohols and blowing agents azodiisobutyric acid dinitrile, benzene sulphohydrazide and diazoaminobenzene.ALSO:Cellular moulded elements are prepared by processing vinyl chloride plastigels-containing a chemically decomposable blowing agent-without decomposition of the blowing agent to form rough shaped elements which are introduced into pressure containers larger than the dimensions of the elements and independent of the shape of the moulded elements to be produced; filling the pressure containers with gas under pressure; heating the containers to gelatinising temperature whereby the blowing agent decomposes and the gases formed are dissolved in the composition of the rough shaped elements without causing expansion; cooling, while maintaining the gas pressure, to the plastic condition below the gelatinising temperature; lowering the gas pressure to atmospheric pressure at which the rough-shaped elements expand while substantially maintaining their dimensional proportions without filling the pressure mould; and removing the warm moulded elements thus obtained from the pressure containers.  Specified are polymers polyvinyl chloride and copolymers of vinyl chloride with vinyl acetate or vinylidene chloride stiffening gelatinising elements aluminium laurate, aluminium stearate, magnesium stearate, calcium carbonate, calcium silicate, colloidal silica, copper phthalocyanine, lead carbonate, organic Mont morillonite derivatives and chemically pure silicic acid in submicroscopically fine division plasticizers dioctyl phthalate, tricresyl phosphate, alkali sebacate, butyl sebacate and esters of polyhydric alcohols and blowing agents azodiisobulyric acid dinitrile, benzene sulphohydrazide and diazoaminobenzene.