JP2009275231A5 - - Google Patents

Claims (9)

A re-peeling pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on at least one surface of a substrate,
The pressure-sensitive adhesive layer comprises an acrylic emulsion-type pressure-sensitive adhesive containing an acrylic copolymer and a crosslinking agent,
The acrylic copolymer uses n-butyl acrylate and 2-ethylhexyl acrylate as monomers, and further uses at least one of acrylic acid or methacrylic acid, and an azo initiator as a polymerization initiator. Coalesced,
The crosslinking agent is an oxazoline-based crosslinking agent;
The loss tangent of the dynamic viscoelastic spectrum at a frequency of 1 Hz and −50 ° C. to 150 ° C. of the pressure-sensitive adhesive layer is
(A) has a convex peak upward in a low temperature range of −20 ° C. or lower,
(B) having a convex peak in the middle temperature range of 10 to 40 ° C.,
(C) Loss tangent at 70 ° C. is 0.38 to 0.57
A pressure-sensitive adhesive sheet for re-peeling, characterized in that Loss tangent in a high temperature range of 50 to 120 ° C. is 0.38 to 0.53 at 50 ° C., 0.40 to 0.65 at 100 ° C., and 0.40 to 0.00 at 120 ° C. 66. The pressure-sensitive adhesive sheet for re-peeling according to claim 2, wherein the pressure-sensitive adhesive sheet is 66. The pressure-sensitive adhesive sheet for re-peeling according to claim 1 or 2, wherein the pressure-sensitive adhesive layer has a storage elastic modulus at a frequency of 1 Hz and 70 ° C of 6.0 x 10 ^{4 to} 2.1 x 10 ⁵ Pa. The pressure-sensitive adhesive sheet for re-peeling according to any one of claims 1 to 3, wherein the content of n-butyl acrylate and 2-ethylhexyl acrylate in the acrylic copolymer is 50 to 99 mass%. The pressure-sensitive adhesive sheet for re-peeling according to any one of claims 1 to 4, wherein a content of acrylic acid and methacrylic acid in the acrylic copolymer is 0.5 to 4.0 mass%. The said acrylic copolymer contains acrylic acid and methacrylic acid, The ratio of methacrylic acid with respect to acrylic acid is 0.5-2.0 by mass ratio, The adhesive for re-peeling in any one of Claims 1-5 Sheet. The pressure-sensitive adhesive sheet for re-peeling according to any one of claims 1 to 6, wherein the functional group number ratio of the oxazoline group of the oxazoline-based crosslinking agent to the carboxyl group in the acrylic copolymer is 0.03 to 0.25. A recycling label using the pressure-sensitive adhesive sheet for re-peeling according to claim 1. The recycling material according to claim 8, wherein a base material sheet mainly composed of polyethylene, polypropylene, polyethylene terephthalate, polystyrene, polyphenylene ether, ABS, polycarbonate, or a composite material thereof is used as the base material of the re-peeling pressure-sensitive adhesive sheet. label.