An apparatus includes a buttress body, an adhesive material, and a containment sheet. The buttress body is sized to fit on an anvil or a staple cartridge deck of a surgical stapler. The adhesive material is disposed on the buttress body. The adhesive material is configured to flow across the buttress body in response to a temperature exceeding a melting temperature. The containment sheet is disposed on the adhesive material. The containment sheet is secured relative to the buttress body such that the containment sheet is configured to contain the adhesive material on the buttress body.