Photoinitiators and UV-crosslinkable acrylic polymers for pressure sensitive adhesives
AssigneeNational Starch and Chemical Investment Holding Corporation
InventorsYuxia Liu, Darwin Bull
Life of this patent
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Abstract
UV-crosslinkable acrylic hotmelt pressure sensitive adhesives comprising acrylic and vinyl monomers, and a polymerizable UV photoinitiator. The photoinitiator comprises a spacer comprising both ethylene oxide and urethane, or urea, carbonate, or siloxane functional groups. The ethylene oxide is directly bonded to the chromophore (e.g., benzophenone) moiety, while the urethane (or urea, carbonate, siloxane) is closely linked to the polymerizable moiety (e.g., styrenic C═C double bond).
Claims20
A photoinitiator having the structural 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.
A UV curable acrylic polymer comprising the following monomer components:
- (a) from about 70 to about 95 parts by weight of acrylic or methacrylic acid derivative of the formula CH2═CH(R1)(COOR2), where R1 is H or CH3 and R2 is a C1-20 alkyl chain,
- (b) 0 to about 30 parts by weight of an acrylic or methacrylic acid derivative of the formula CH2═CH(R1)(COOR2), where R1 is H or CH3 and R2 is an hydroxyl-functional C1-20 alkyl chain,
- (c) 0 to about 20 parts by weight of an acrylic or vinyl compound containing a carboxy or anhydride functional group,
- (d) 0 to about 30 parts by weight of acrylic or vinyl compounds containing an amine, amide, urethane, epoxide or isocyanate functional group and
- (e) from about 0.01 to about 15 parts by weight of a photoinitiator having the structural 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.