Hot-tackifying adhesive tape
AssigneeMinnesota Mining and Manufacturing Company
InventorRobert H. Stow
Life of this patent
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Abstract
Hot-tackifying adhesive tape, the adhesive layer of which is an acrylic polymer which is nontacky or poorly tacky at ordinary room temperature, but at any temperature over a wide range of elevated temperatures, it becomes tacky and adheres upon contact to clean substrates without the application of significant pressure. Good bonds are immediately formed at a tackifying temperature without the necessity of crosslinking or other chemical reactions.
Claims21
Heat-activatable substantially non-thermosettable, substantially non-crosslinkable adhesive tape that can be wound upon itself in roll form for convenience in storage and use and comprises a heat-resistant flexible backing and an adhesive layer which is nontacky or poorly tacky at 20.degree. C., said adhesive layer comprises an acrylic polymer of acrylic ester monomer and is free of a reactive hot-melt resin, wherein the improvement comprises:
- (1) said acrylic ester monomer provides at least 50 mol percent of the acrylic polymer of said adhesive layer,
- (2) said acrylic polymer has a Tg or a weightaveraged Tg of from -10.degree. C. to 80.degree. C., and
- (3) said adhesive layer has a Shear value of at least 25 minutes at 65.degree. C., said adhesive layer adheres well to a clean substrate upon contact when heated to a temperature about 50.degree. C. above the Tg or weight-averaged Tg of said acrylic polymer.
Dependencies are inferred from the claim text.