Cationic UV-crosslinkable acrylic polymers for pressure sensitive adhesives
AssigneeHenkel US IP LLC
InventorsYuxia Liu, Peter Palasz, Charles W. Paul, Paul B. Foreman
Life of this patent
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Abstract
An ultraviolet (UV) crosslinkable acrylic pressure sensitive adhesive comprises an acrylic copolymer and a cationic photoinitiator. The acrylic copolymer comprises pendant reactive functional groups. The pressure sensitive adhesive formed from the acrylic copolymer with the pendant reactive functional groups result in high green strength and/or high temperature holding strength of the adhesive.
Claims23
An ultra-violet curable pressure sensitive adhesive comprising an acrylic polymer and a cationic photoinitiator, wherein said acrylic polymer is prepared from the group consisting of:
- (i) an acrylic monomer consisting of an acrylic or methacrylic acid derivative of the formula CH2═CH(R1)(COOR2), wherein R1 is H or CH3 and R2 is C1-20 alkyl chain;
- (ii) a monomer,
- wherein said monomer comprises a pendant reactive functional group selected from cycloaliphatic epoxide, oxetane or mixtures thereof, and contains from about 0.001 to about 0.015 equivalent per 100 g of said acrylic polymer;
- wherein the acrylic polymer (a) is essentially free of multi-(meth)acrylate, (b) has a Tg value less than 0° C., and (c) has a weight average molecular weight from about 50,000 to about 1,000,000 g/mol;
- and
- wherein the ultra-violet curable pressure sensitive adhesive has a viscosity range of 1,000-500,000 mPa·s at 80-180° C.
An ultra-violet curable pressure sensitive adhesive comprising an acrylic polymer and a cationic photoinitiator, wherein said acrylic polymer is prepared from:
- (i) an acrylic monomer consisting of an acrylic or methacrylic acid derivative of the formula CH2═CH(R1)(COOR2), wherein R1 is H or CH3 and R2 is C1-20 alkyl chain;
- (ii) a monomer,
- wherein said monomer comprises a pendant reactive functional group that is present from about 0.001 to about 0.015 equivalent per 100 g of said acrylic polymer;
- wherein the acrylic polymer (a) is essentially free of multi-(meth)acrylate, (b) has a Tg value less than 0° C., and (c) has a weight average molecular weight from about 50,000 to about 1,000,000 g/mol;
- and
- wherein the pendant reactive functional group is a benzophenone having the formula:
- where
- Z is S, O, CH2, or NH,
- R1-8 are independently H, Cl, Br, I, F, C1-24 alkoxy, C1-24 alkyl, or aryl;
- and wherein at least one of R1-8 must comprise a —W—X—Y group, where
- W is a C1-12 alkylene or C1-12 oxyalkylene,
- X is carbonate, urethane, urea, tetramethyldisiloxane or a combination thereof, and
- Y is —R9—C(R10)═CH2, where R9 is a linear or branched C2-10 alkylene or C2-10oxyalkylene, or arylene or derivative thereof, and R10 is H or CH3.
An ultra-violet curable pressure sensitive adhesive comprising an acrylic polymer and a cationic photoinitiator, wherein said acrylic polymer comprises:
- (i) an acrylic monomer consisting of an acrylic or methacrylic acid derivative of the formula CH2═CH(R1)(COOR2), wherein R1 is H or CH3 and R2 is C1-20 alkyl chain;
- (ii) a monomer, wherein the monomer comprises a plurality of pendant reactive functional groups selected from
- (1) mono-substituted oxirane, and
- (2) cycloaliphatic epoxide, oxetane, benzophenone or mixtures thereof, and
- wherein said monomer contains from about 0.001 to about 0.015 equivalent per 100 g of said acrylic polymer;
- wherein said acrylic polymer (a) is essentially free of multi-(meth)acrylate (b) has a Tg value less than 0° C., and (c) has a weight average molecular weight from about 50,000 to about 1,000,000 g/mol;
- and
- wherein the pendant reactive functional group comprises a benzophenone having the formula:
- where
- Z is S, O, CH2, or NH,
- R1-8 are independently H, Cl, Br, I, F, C1-24 alkoxy, C1-24 alkyl, or aryl;
- and wherein at least one of R1-8 must comprise a —W—X—Y group, where
- W is a C1-12 alkylene or C1-12 oxyalkylene,
- X is carbonate, urethane, urea, tetramethyldisiloxane or a combination thereof, and
- Y is —R9—C(R10)═CH2, where R9 is a linear or branched C2-10 alkylene or C2-10oxyalkylene, or arylene or derivative thereof, and R10 is H or CH3.
Dependencies are inferred from the claim text.