Container closure gasket made from a novel plastisol composition

Claim 2

a plasticizer for said resin component b. contacting said composition for about 2 to 5 seconds with a die heated to a temperature which is at least sufficient to gell said plastisol composition, and c. heating the gelled plastisol composition to advance the plastisol to a fluxed state.

Claim 3

The closure of claim 1 wherein said composition additionally contains about 0.15 to 3 weight percent, based on the total weight of said resin component and said plasticizer, of a siliceous material.

Claim 4

The closure of claim 1 wherein said mass-polymerized vinyl chloride polymer has a particle structure consisting of aggregates of interpenetrating spheres, said spheres having a diameter of less than 1,000 angstroms.

Claim 5

The closure of claim 4 wherein said polymer is a homopolymer of vinyl chloride.

Claim 6

The closure of claim 1 wherein said mass-polymerized vinyl chloride polymer has a specific viscosity at 30*C. (0.4 g/100 ml in nitrobenzene) of at least 0.30.

Claim 7

A container closure comprising a cap having deposited therein a resinous mass which functions as a gasket to seal the container when the closure is in sealing relationship with the container, said resinous mass comprising a fluxed plastisol of a composition containing (a) 100 parts by weight of a vinyl chloride resin component containing 10 to 50 parts by weight of emulsion-polymerized vinyl chloride homopolymer or copolymer thereof containing up to about 20 weight percent of ethylenically unsaturated comonomer copolymerizable therewith and 50 to 90 parts by weight of mass-polymerized vinyl chloride homopolymer or copolymer thereof containing up to about 20 weight percent of ethylenically unsaturated comonomer copolymerizable therewith; (b) about 50 to 110 parts by weight per hundred parts of said resin component of a plasticizer; and (c) about 0.15 to 3 weight percent, based on the total weight of said resin component and plasticizer, of a siliceous thickening agent.

Claim 8

The closure of claim 7 wherein said mass-polymerized vinyl chloride polymer has a particle structure consisting of aggregates of interpenetrating spheres, said spheres having a diameter of less than 1,000 angstroms.

Claim 9

The closure of claim 8 wherein said spheres have a diameter in the range of about 75 to 200 angstroms.

Claim 10

The closure of claim 7 wherein said plasticizer is di-2-ethylhexyl phthalate.

Claim 11

The closure of claim 7 wherein said plasticizer is di-isodecyl phthalate.

Claim 12

The closure of claim 7 wherein said siliceous material is colloidal silica.

Claim 13

The closure of claim 7 wherein said mass-polymerized vinyl chloride polymer has a specific viscosity at 30*C. (0.4 g/100 ml in nitrobenzene) of at least 0.30.

Claim 14

A container closure comprising a cap having deposited therein a resinous mass which functions as a gasket to seal the container when the closure is in sealing relationship with the container, said resinous mass comprising a fluxed plastisol of a composition containing (a) 100 parts of a vinyl chloride resin component containing 15 to 25 parts by weight of dispersion grade vinyl chloride homopolymer or copolymer thereof containing up to about 20 weight percent of ethylenically unsaturated comonomer copolymerizable therewith and 75 to 85 parts by weight of mass-polymerized vinyl chloride homopolymer or copolymer thereof containing up to about 20 weight percent of ethyoenically unsaturated comonomer copolymerizable therewith having a particle structure consisting of interpenetrating spheres having a diameter of less than 1,000 angstroms and a specific viscosity at 30*C. (0.4 g/100 ml in nitrobenzene) of at least 0.30, (b) about 75 to 85 parts by weight of a plasticizer per hundred parts by weight of said resin component and (c) about 0.5 to 1 weight percent, based on the total weight of said resin component and plasticizer, of a siliCeous material.