Abstract Pressure-sensitive polyurethane adhesives having the combined properties of high peel adhesion, quick stick, shear strength, and resistance to hydrocarbon solvents comprise the crosslinked polyurethane reaction product of the in situ reaction of polyhydroxyl terminated polyethers and polyethers with polyisocyanates to provide a product having a molecular weight between crosslinks of about 6,000 to about 40,000 and a urethane group concentration of about 0.7 to 1.3 per 1,000 gms of polymer, and trackifier comprising the reaction product of cyclic terpene alcohols and aromatic isocyanates. The adhesive is coated as a layer on a backing of paper or polymeric film and wound in a roll. A silicone treated release liner may be adhered to the adhesive layer. The adhesive may also be coated as a transfer film on a release liner.
Tape of claim 1 wherein said backing is biaxially oriented polyethylene terephthalate film.
Claim 2
Dependent Claim
11 words
Tape of claim 1 wherein said backing is polyvinyl chloride film.
Claim 3
Dependent Claim
159 words
An adhesive tape comprising a thin, flexible sheet of paper having adhered to one major surface thereof a pressure-sensitive polyurethane adhesive and having a thin, flexible, silicone treated release liner adhered to said adhesive, said adhesive comprising a crosslinked polyurethane and a tackifier for said crosslinked polyurethane, said crosslinked polyurethane being a cured reaction product of components comprising a polyol and a polyisocyanate, said crosslinked polyurethane having a molecular weight between crosslinks of 6,000 to 40,000 and a urethane group concentration of 0.7 to 1.3 urethane groups per 1,000 grams of said crosslinked polyurethane, said tackifier comprising a resin which is the reaction product of the components comprising a cyclic terpene alcohol and an aromatic polyisocyanate, said resin having been combined with said crosslinked polyurethane prior to the completion of the curing of said crosslinked polyurethane, said tape being wound directly upon itself in overlapping convolutions in roll form and capable of being unwound therefrom without delaminating or offsetting.