A patch according to an embodiment of the present invention includes a support and a pressure-sensitive adhesive layer provided on at least one surface of the support. The pressure-sensitive adhesive layer contains an acrylic copolymer obtained by copolymerizing a monomer mixture containing (a) a (meth)acrylic acid alkyl ester, (b) a hydroxyl group-containing monomer, and (c) a diketone group-containing monomer.
