Laminate and packaging bag

A laminate comprising a first base material layer, a second base material layer, and a sealant layer in this order,

• wherein the first base material layer, the second base material layer, and the sealant layer all include a polyolefin film;
• the sealant layer consists of a polyolefin and optionally, at least one of an antioxidant and a light stabilizer;
• wherein
• the laminate further comprises (a) an adhesive layer in directed contact with a surface of the polyolefin film of one of the first base material layer and the second base material layer;
• (b) an inorganic oxide layer in direct contact with the adhesive layer;
• and (c) a gas barrier coating layer in direct contact with each of the inorganic oxide layer and a surface of the polyolefin film of the other of the first base material layer and the second base material layer;
• the gas barrier coating layer is formed from a composition containing at least one selected from the group consisting of a hydroxyl group-containing polymer compound, a metal alkoxide, a silane coupling agent, and hydrolyzates thereof;
• each of the first base material layer, the second base material layer, and the sealant layer has a heat shrinkage rate, in a travel direction (MD direction) after heating at 120° C. for 15 minutes, which satisfies the following inequalities:
• Heat shrinkage rate of the second base material layer≤5% (Inequality 1)
• Heat shrinkage rate of the second base material layer≥Heat shrinkage rate of the first base material layer (Inequality 2)
• Heat shrinkage rate of the second base material layer≥Heat shrinkage rate of the sealant layer (Inequality 3),
• wherein
• Heat shrinkage rate (%)=(Travel-direction length before heating−Travel-direction length after heating)/Travel-direction length before heating×100, wherein the sealant layer consists of the polyolefin and the antioxidant;
• the sealant layer consists of the polyolefin and the light stabilizer;
• or the sealant layer consists of the polyolefin, the antioxidant and the light stabilizer.