Silicone release composition
AssigneeP. H. Glatfelter Company
InventorW. Michael Reed
Life of this patent
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Abstract
A silicone release coating emulsion includes a reactive crosslinkable silicone, a catalyst and a high molecular weight, water soluble or water dispersible polymeric thickening agent such as polyethylene oxide. The polymeric thickening agent has a molecular weight greater than about 100,000 g/mole Mw. The silicone release emulsion is applied as a coating to a substrate, and particularly paper, and cured to form a release coating for pressure sensitive adhesives. The silicone emulsion exhibits improved holdout of the silicone from the substrate.
Claims22
A process of forming a silicone release coating and increasing silicone holdout on a substrate, comprising
- a) applying a coating of a release composition of an aqueous emulsion to a substrate, wherein the aqueous emulsion contains from about 10% to 98% of at least one curable silicone for forming a release coating, an effective amount of a silicone crosslinking catalyst and about 0.01% to about 30% of at least one polymeric thickening agent capable of promoting silicone holdout on a substrate, wherein said thickening agent is soluble or partially soluble in water at room temperature and is a substantially linear aliphatic polymer having a weight average molecular weight of at least about 100,000 g/mole wherein said percentages are by weight actives based on the total weight of the actives in the emulsion, and wherein said linear aliphatic polymer is selected from the group consisting of polyacrylamides, polypropylene oxide, polyethylene oxides, and polyethylene oxide-polypropylene oxide copolymers;
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- b) drying and curing the coating.
A process of promoting silicone holdout in a silicone release coating on a substrate, comprising
- a) applying a coating of a silicone release composition on a substrate, wherein said silicone release composition is an aqueous emulsion comprising from about 10% to 98% of at least one curable silicone capable of forming a silicone release coating, an effective amount of a silicone crosslinking catalyst to crosslink said silicone, and about 0.01% to about 30% of a silicone holdout promoting linear aliphatic polymer which is water soluble or partially soluble in water at room temperature and has a weight average molecular weight of at least 100,000 g/mole, wherein said percentages are by weight actives based on the total weight of the actives in the emulsion, and wherein said linear aliphatic polymer is selected from the group consisting of polyacrylamides, polypropylene oxide, polyethylene oxide, and polyethylene oxide-polypropylene oxide copolymers.
A process of forming a silicone release coating and increasing silicone holdout on a substrate, comprising:
- a) applying a coating of a release composition of an aqueous emulsion to a substrate, wherein the aqueous emulsion contains from about 10% to 98% of at least one curable silicone for forming a release coating, an effective amount of a silicone crosslinking catalyst and about 0.01% to about 30% of at least one polymeric thickening agent capable of promoting silicone holdout on a substrate, wherein said thickening agent is soluble or partially soluble in water at room temperature and is a substantially linear aliphatic polymer having a weight average molecular weight of at least about 500,000 g/mole, wherein said percentages are by weight actives based on the total weight of the actives in the emulsion;
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- b) drying and curing the coating.
Dependencies are inferred from the claim text.