Pressure-sensitive adhesive crosslinked by copolymerizable aromatic ketone monomers

A method of preparing an article comprising a support member having a surface, at least a portion of which surface is coated with a pressure-sensitive skin adhesive composition, said method comprising the steps of:

• (a) preparing a precursor of said pressure-sensitive skin adhesive composition by copolymerizing A monomers and PX monomers wherein:
• A is a monomeric acrylate or methacrylate ester of a non-tertiary alcohol or a mixture of non-tertiary alcohols, said alcohols having from 1 to 14 carbon atoms with the average number of carbon atoms being about 4-12;
• and
• PX is a copolymerizable mono-ethylenically unsaturated aromatic ketone monomer free of ortho-aromatic hydroxyl groups and has the formula:
• ##STR3## wherein R is lower alkyl or phenyl, provided that R may be optionally substituted with one or more halogen atoms, alkoxy groups or hydroxyl groups, further provided that when R is phenyl substituted with one or more hydroxyl groups, any such hydroxyl groups must be meta or para to the aromatic carbonyl, X is halogen, alkoxy or hydroxyl, provided that when X is a hydroxyl group, that X must be meta or para to the aromatic carbonyl, n is an integer from 0 to 4, Y is a divalent linking group, and X is an alkenyl group or an ethylenically unsaturated acyl group;
• said PX monomer comprising from about 0.025% to about 0.5% by weight of the resultant copolymer and the degree of polymerization of said copolymer being such that said copolymer has an inherent viscosity of from about 0.5 dl/g to about 1.4 dl/g;
• (b) coating at least a portion of the surface of said support member with said pressure-sensitive skin adhesive precursor;
• and
• (c) exposing said pressure-sensitive skin adhesive precursor to sufficient ultraviolet radiation to crosslink said precursor such that the resultant pressure-sensitive skin adhesive composition has a creep compliance of from about 1.2.times.10.sup.-5 cm.sup.2 /dyne to about 2.3.times.10.sup.-5 cm.sup.2 /dyne when measured after about 3 minutes of subjection to stress.

A method of adhering an adherend to a substrate comprising interposing between said adherend and said substrate an effective amount of an adhesive composition comprising a crosslinked copolymer comprised of A monomers and PX monomers, wherein:

• A is a monomeric acrylate or methacrylate ester of a non-tertiary alcohol or a mixture of non-tertiary alcohols, said alcohols having from 1 to 14 carbon atoms with the average number of carbon atoms being about 4-12;
• and
• PX is a copolymerizable mono-ethylenically unsaturated aromatic ketone monomer free of ortho-aromatic hydroxyl groups and has the formula:
• ##STR4## wherein R is lower alkyl or phenyl, provided that R may be optionally substituted with one or more halogen atoms, alkoxy groups or hydroxyl groups, further provided that when R is phenyl substituted with one or more hydroxyl groups, any such hydroxyl groups must be meta or para to the aromatic carbonyl, X is halogen, alkoxy or hydroxyl, provided that when X is a hydroxyl group, that X must be meta or para to the aromatic carbonyl, n is an integer from 0 to 4, Y is a divalent linking group, and Z is an alkenyl group or an ethylenically unsaturated acyl group;
• said PX monomer comprising from about 0.025% to about 0.5% by weight of said copolymer and the degree of polymerization of said copolymer being such that said copolymer has an inherent viscosity of from about 0.5 dl/g to about 1.4 dl/g before crosslinking, whereby upon crosslinking said copolymer by ultraviolet irradiation of said PX containing copolymer the adhesive composition has a creep compliance of from about 1.2.times.10.sup.-5 cm.sup.2 /dyne to about 2.3.times.10.sup.-5 cm.sup.2 /dyne when measured after about 3 minutes of subjection to stress.