Patent GB-1012274-A (GB)
Title: Improvements in or relating to polyvinyl resins
IPC: C08J3/22
Filed: 1963-03-14
Abstract: Dry, free-flowing, fast-fusing vinyl chloride polymer powder compositions for application in fluidizable resin coating processes, are prepared by thoroughly premixing all of the ingredients, at least one of which is liquid, other than the resin components to form a homogeneous mixture, introducing a major proportion of an absorptive-type vinyl chloride polymer resin having a uniform particle size of 30 to 200 microns and an accelerated rate of fusion when subjected to temperatures above its softening point compared with its rate of fusion below its softening point into a blade-type mixing apparatus having a shearing speed within the range of 60 to 2000 r.p.m., starting the mixing apparatus and then adding the mixture of non-resinous ingredients to the resin, continuing the mixing process while the temperature of the blend is gradually raised to a temperature below the softening temperature of the composition and all of the liquid ingredients therein are absorbed by the resin, cooling the composition with mixing to a temperature substantially lower than the blending temperature, adding a minor proportion of a vinyl chloride polymer resin having a particle size not exceeding 3 microns to the cooled composition and continuing the mixing operation until the added resin has been thoroughly dispersed, and finally discharging and recovering the dry, free-flowing vinyl chloride polymer resin powder composition from the mixing apparatus.  The resin may be polyvinyl chloride, or a copolymer of vinyl chloride with up to 15% by weight of vinylidene chloride, vinyl esters or alkyl acrylates.  The absorptive-type resin may be prepared by suspension polymerization and the resin of particle size below 3 microns by emulsion polymerization.  The non-resin ingredients may be plasticizers, stabilizers, fillers and pigments, many of which are specified.  The compositions may be used for coating substrates, e.g. metal articles, by dipping the heated articles in fluidized beds of the compositions.  Examples describe the preparation of free-flowing compositions comprising suspension and emulsion polyvinyl chlorides, epoxidized soya bean oil and tin mercaptide, together with (1) dioctyl phthalate and titanium dioxide, (2) dioctyl adipate and titanium dioxide, (3) dioctyl adipate, (4) dioctyl phthalate and calcium carbonate, and (5) tricresyl phosphate.ALSO:Substrates may be coated by immersing the heated substrates in fluidized dry, free-flowing, fast-fusing vinyl chloride polymer resin powder compositions prepared by thoroughly premixing all of the ingredients, at least one of which is liquid, other than the resin components to form a homogeneous mixture, introducing a major proportion of an absorptive-type vinyl chloride polymer resin having a uniform particle size of 30-200 microns and an accelerated rate of fusion when subjected to temperatures above its softening point compared with its rate of fusion below its softening point into a blade type mixer having a shearing speed within the range 60-2000 r.p.m., starting the mixer and then adding the mixture of non-resinous ingredients to the resin, continuing the mixing process while the temperature of the blend is gradually raised to a temperature below the softening point of the composition and all of the liquid ingredients therein are absorbed by the resin, cooling the composition with mixing to a temperature substantially below the blending temperature, adding a minor proportion of a vinyl chloride polymer resin having a particle size not exceeding 3 microns to the cooled composition and continuing the mixing operation until the added resin has been thoroughly dispersed, and discharging and recovering the dry, free-flowing composition from the mixer. Preferred substrates are metals.  Preferred resins are suspension and emulsion polyvinyl chlorides.  The non-resinous ingredients may be plasticizers, stabilizers, fillers and pigments.  Examples describe the coating of steel plates with compositions comprising suspension and emulsion polyvinyl chlorides, epoxidized soya bean oil, tin mercaptide and (1) dioctyl phthalate and titanium dioxide, (2) dioctyl adipate and titanium dioxide, (3) dioctyl adipate, (4) dioctyl phthalate and calcium carbonate, and (5) tricresyl phosphate.