Adhesive tape

A pressure-sensitive adhesive tape, comprising a base material and a pressure-sensitive adhesive layer including thermally expandable microspheres and an acrylic pressure-sensitive adhesive,

• wherein the base material is a resin sheet consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyethylene (PE), polypropylene (PP), an ethylene-propylene copolymer, an ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), wholly aromatic polyamide (aramid), polyimide (PI), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), a fluorine-based resin, or polyether ether ketone (PEEK),
• wherein the thermally expandable microspheres are each formed of a shell and a volatile substance contained in the shell,
• wherein the volatile substance includes at least one of isopentane or isooctane,
• wherein the shell is formed of a resin having a glass transition temperature (Tg) of 120° C. or more,
• wherein the resin for forming the shell contains a constituent unit having a carboxyl group,
• wherein a difference (Tg−bp) between a boiling point (bp) of the volatile substance and the glass transition temperature (Tg) of the resin for forming the shell is 50° C. to 150° C., and
• wherein a pressure-sensitive adhesive strength “c” of the pressure-sensitive adhesive tape, when a pressure-sensitive adhesive surface of the pressure-sensitive adhesive tape is bonded to a polyethylene terephthalate film after a cycle involving heating to 140° C. and then cooling to 25° C. is performed twice, is 50% or more with respect to an initial pressure-sensitive adhesive strength “a” of the pressure-sensitive adhesive tape, when the pressure-sensitive adhesive surface of the pressure-sensitive adhesive tape is bonded to the polyethylene terephthalate film under an ambient temperature of 25° C.