Abstract:
Compositions for lining closures in glass or metal containers comprise a resin, a plasticizer in which the resin is soluble only at elevated temperatures and a filler in such proportion that the composition will withstand a force of 3G at room temperature without flow. Specified resins are polyvinyl chloride and vinyl chloride-vinyl acetate copolymer and specified plasticizers are dioctyl phthalate alone or containing zinc resinate, tricresyl and tributyl phosphates. Suitable fillers are metallic oxides, talc, magnesium and calcium silicates, calcium carbonate, slate flour, cotton floc, wood flour, lignin, ground cork, hard rubber dust and ground thermosetting plastic waste. The compositions may also contain heat stabilizers, e.g. that known under the name "Stabelan." In the process, the ingredients are ground and after application the compositions are heated to flux and then cooled.ALSO:Closures for glass or metal containers are lined by extruding through an orifice into a rotating cap a plastic composition comprising a resin, a plasticizer in which the resin is soluble only at elevated temperatures and a filler in such proportion that the composition will withstand a force of 3 G. at room temperature without flow, rotating the cap at a speed to produce a thrust greater than 3 G. to smooth out inequalities in the plastic lining, heating to flux the composition and allowing the cap to cool. Specified resins are polyvinyl chloride and a copolymer of vinyl chloride and vinyl acetate and specified plasticizers are dioctyl phthalate, tricresyl and tributyl phosphates. Suitable fillers are metallic oxides, talc, calcium carbonate, magnesium and calcium silicates, slate flour, cotton floc, wood flour, lignin, ground cork, hard rubber dust and ground thermosetting plastic waste. The lining machines should have high pressure delivery and the caps may be rotated at 400-500 r.p.m.