Sheet material having composite fluorochemical-silicone release coatings
AssigneeMinnesota Mining and Manufacturing Company
InventorCharles M. Morrow
Life of this patent
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Abstract
Sheet materials, such as pressure-sensitive tapes or release liners, are provided with a spectrum of composite coatings having desired release values. The release surfaces, which present both fluorochemical polymer and cured silicone polymer areas, are formed by first applying specific types of fluorochemical polymer and then overcoating with silicone-forming reactants.
Claims13
Sheet material provided with a composite release surface comprising first and second coatings on at least one side, normally tacky and pressure-sensitive adhesive adhering less strongly to the coatings than to the same sheet material in the absence of the coatings, the exposed release surface consisting essentially of areas of said first coating and other areas of said second coating
- said first coating consisting essentially of a solid fluorochemical polymer having surface energy characteristics such that a drop of 100% ethanol forms a contact angle of at least 30.degree. when placed on the surface of a smooth dry film of said fluorochemical polymer, and
- said second coating consisting essentially of a cured silicone polymer consisting essentially of polydimethylsiloxane gum, crosslinked with polymethylhydrogensiloxane, whereby pressure-sensitive adhesive exhibits an average adhesion to the composite release surface in the range of 8-350 g/cm width, less than to said first coating alone and greater than to said second coating alone.
Dependencies are inferred from the claim text.