Polyurethane composite adhesive for aluminum plastic film and preparation method of polyurethane composite adhesive

The invention relates to the technical field of adhesives, in particular to a polyurethane composite adhesive for an aluminum-plastic film and a preparation method of the polyurethane composite adhesive, the polyurethane composite adhesive is bi-component polyurethane glue containing a main agent and a curing agent, the main agent is prepared by compounding branched-chain phthalic anhydride polyester polyol and crystalline polyester polyol, and the curing agent is prepared by compounding branched-chain phthalic anhydride polyester polyol and crystalline polyester polyol. The water resistance of the composite adhesive can be improved on the basis of ensuring high temperature resistance and bonding performance, the initial viscosity of the composite adhesive is improved, the adhesive force of the adhesive to a base material is increased, epoxy resin is selected as an auxiliary agent, an IPN network form is formed during curing, the heat and humidity resistance of the composite adhesive is further improved, and