Repeelable adhesive including photocurable adhesive and heat foaming agent and repeelable adhesive tape including the same

A repeelable adhesive comprising:

• a photocurable adhesive prepared by polymerizing a photocurable adhesive composition comprising an acrylic copolymer, a photocurable acrylate-based monomer, a photocurable urethane acrylate-based oligomer, and a crosslinking agent, in the presence of a photoinitiator;
• and
• a heat foaming agent,
• wherein the acrylic copolymer consists of a polymerized monomer selected from the group consisting of 2-ethylhexyl acrylate (2-EHA), vinyl acetate (VA), methyl methacrylate (MMA), acrylic acid (AA), and combinations thereof,
• the photocurable acrylate-based monomer includes a monomer selected from the group consisting of 1,4-hexanediol diacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol pentaacrylate, tris(2-hydroxyalkyl) isocyanurate triepoxide, triallylisocyanurate, tris(2-hydroxyalkyl) isocyanurate triacrylate, isophorone diisocyanurate, alkyldiisocyanurate, alicyclic diisocyanurate compound, alkyl diisocyanurate trimer, decyl acrylate, lauryl acrylate, stearyl acrylate, tetrahydrofurfuryl acrylate, cyclic trimethylolformal acrylate, phenoxypolyethylene glycol acrylate, benzyl acrylate, epoxy ethyl acrylate, phenoxyethylacrylate, tripropylene glycol diacrylate, and combinations thereof,
• the crosslinking agent includes a crosslinking agent selected from the group consisting of 2,4-toluene diisocyanate, 2.6-toluene diisocyanate, 1.5-naphthalene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, P-xylylenediisocyanate, M-xylylenediisocyanate, dicyclohexylmethane diisocyanate, and combinations thereof, and,
• wherein, based on 100 parts by weight of the acrylic copolymer,
• an amount of the photocurable acrylate-based monomer is 1 part by weight to 50 parts by weight,
• an amount of the photocurable urethane acrylate-based oligomer is 5 parts by weight to 100 parts by weight,
• an amount of the crosslinking agent is 0.1 parts by weight to 10 parts by weight, and
• an amount of the photoinitiator is 0.1 parts by weight to 10 parts by weight,
• wherein the repeelable adhesive after curing by irradiation has a gel fraction of 80% to 86.5% calculated using Equation 2 based on ASTM D2765,
• Gel fraction (%)=(W3−W1)/(W2−W1)×100 Equation 2
• wherein W1 represents the weight of a bag, W2 represents the weight of the bag containing a specimen before extraction, and W3 represents the weight of the bag after extraction.