Patent GB-660361-A (GB)
Title: Container sealing compositions
IPC: C09K3/10
Filed: 1948-06-24
Abstract: A container sealing composition comprises a congealed mass of plasticizer and a congelation agent having uniformly distributed therein discreet particles of filler and of a resin which is paste-forming with the plasticizer, the resin being substantially insoluble in the plasticizer at room temperature but soluble above 150 DEG  F., and the congelation agent constituting from 2 to 25 per cent by weight of the composition, the composition being a stiff pasty gel at room temperature but becoming liquid at 90 DEG  to 150 DEG  F. and being convertible into a permanent rubbery mass by heating to above 150 DEG  F. when the resin solvates in the plasticizer and then cooling to room temperature.  Specified resins are polyvinyl chloride, vinyl chloride-acetate copolymers and vinylidene chloride-acrylonitrile copolymer.  The congelation agent is such that the composition having congealed at room temperature exhibits no flow for at least one half-minute when subjected to a force of 1 G. at a temperature of 90 DEG  to 150 DEG  F.  Suitable compounds are paraffin wax, polyamide wax, japan wax, amorphous petroleum wax, candelilla wax, beeswax, stearyl alcohol, cetyl alcohol, diglycol stearate, myristic acid, polyethylene glycol, mixed long-chain amides and octadecenyl amine.  The filler is used in sufficient proportions to prevent flow of the composition under its own weight when molten.  Specified fillers are barytes, fibrous magnesium silicate, talc, kaolin, lignin, ground calcium carbonate, aluminium oxide, slate dust, alphacellulose floc, graphite, mica, ground cork, lithopone, diatomaceous earth, calcium silicate, clay and titanium oxide.  Examples of plasticizers are dioctyl phthalate, dioctyl sebacate, tricresyl phosphate, dicapryl phthalate, petroleum fractions high in aromatic and naphthenic hydrocarbons, methyl acetyl ricinoleate and the composition known under the name "Flexol N8."  In use, the composition is heated to a liquid, but unfluxed, state and discharged under pressure through a heated nozzle on to a metal closure where it suddenly congeals on contact with the cooler surface and is not displaced by jolting.  The closures are then passed into an oven where the paste is fluxed and on cooling permanent rubbery gaskets are obtained.  Wetting agents, e.g. zinc resinate, tributyl phthalate, magnesium resinate, sorbide dioleate, gum rosin, oil-free lecithin and sodium petroleum sulphonate, are preferably incorporated in the compositions and other ingredients mentioned are carbon black and titanium dioxide pigments and phosphoric, maleic or benzoic acid for plasticity adjustment of kaolin.  Specifications 398,091, 548,220, 573,840 and 575,393 are referred to.ALSO:Container closures are lined on high speed rotating machinery by placing the closure on the chuck, lining it with a resin-plasticizer composition heated to a fluid state, continuing the rotation until the composition congeals by losing heat to the closure, transferring the lined closure to an oven where it is heated to above 150 DEG F. until the resin fluxes in the plasticizer and forms a permanent rubbery gel on cooling.  The composition comprising a congealed mass of plasticizer and congelation agent having uniformly distributed therein discrete particles of filler and of a resin which is paste-forming with the plasticizer, the resin being substantially insoluble in the plasticizer below 150 DEG F., and the congelation agent constituting from 2 to 25 per cent by weight of the composition, the composition being a stiff pasty gel at room temperature but becoming liquid at 90 DEG  to 150 DEG  F.  Specified resins are polyvinyl chloride, vinyl chloride-acetate copolymers and vinylidene chloride-acrylonitrile copolymer.  The congelation agent is such that the composition having congealed at room temperature exhibits no flow for at least half a minute when subjected to a force of 1G at a temperature of 90 DEG  to 150 DEG F., at which temperature it is applied to the closure. Suitable compounds are paraffin wax, polyamide wax, japan wax, amorphous petroleum wax, candelilla wax, beeswax, stearyl and cetyl alcohols, diglycol stearate, myristic acid, polyethylene glycol, mixed long chain amides and octadecenyl amine.  A small drop in temperature at the fluid state obtained by contacting the closure causes a sudden congealing of the composition and spattering and throwing are prevented.  The filler is used in sufficient proportions to prevent flow of the composition under its own weight when molten. Specified fillers are barytes, fibrous magnesium silicate, talc, kaolin, lignin, ground calcium carbonate, aluminium oxide, slate dust, alpha-cellulose floc, graphite mica, ground cork, lithopone, diatomaceous earth, calcium silicate, clay and titanium oxide. Examples of plasticizers are dioctyl phthalate, dioctyl sebacate, tricresyl phosphate, dicapryl phthalate, petroleum fractions high in aromatic and naphthenic hydrocarbons, methyl acetyl ricinoleate and the composition known under the name "Flexol N8."  Wetting agents and pigments are also included in the compositions.  Flat top and side seal closures may be produced and chuck speeds of 356 to 700 r.p.m. are possible.  The compositions are particularly useful for glass closures but may be used for metal, paper or plastic containers. Specifications 398,091, 548,220, 573,840 and 575,393, [all in Group IV], are referred to.