Radiation curable hot melt pressure sensitive adhesives
AssigneeNational Starch and Chemical Investment Holding Corporation
InventorsRama Chandran, Roopram Ramharack, Irwin J. Davis, John C. Leighton
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Abstract
This invention is a hot melt pressure sensitive adhesive formed by copolymerizing acrylic, or a combination of acrylic and vinyl, monomers with the functional monomer, 1-(1-isocyanato-1-methyl ethyl)-3-(1-methyl ethenyl)benzene m-TMI, to give a saturated polymer with pendant vinyl groups that are crosslinked by UV or EB radiation.
Claims7
A hot melt, pressure sensitive adhesive polymer, characterized as initially having pendant vinyl groups that are thermally stable to 180.degree. C. and that subsequently are crosslinked on exposure to Electron Beam or Ultra Violet radiation, wherein
- (a) the polymer is prepared by copolymerizing acrylic, or a combination of acrylic and vinyl, monomers, at least one of which also contains a functional group selected from the group consisting of hydroxyl, amine, carboxyl and amide, the monomers chosen to result in a copolymer that is a viscoelastic solid at ambient temperature, has a glass transition temperature (Tg) in the range of -60.degree. C. to +5.degree. C., and has a Brookfield viscosity in the range of 500,000 to 1,000 mPa.s at temperatures in the range of 80.degree. C. to 180.degree. C.;
- (b) the pendant vinyl groups are introduced to the polymer by reacting the functional group on the copolymer with 1-(1-isocyanato-1-methyl ethyl)-3-(1-methyl ethenyl)benzene (m-TMI) in a condensation reaction;
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- (c) the polymer is exposed to electron beam or ultraviolet radiation sufficient to crosslink the pendant vinyl groups to impart pressure sensitivity.
Dependencies are inferred from the claim text.