▎ 摘　　要

NOVELTY - A reinforcing masterbatch comprises phase solvent containing 80-90 %mass polypropylene (PP) graft copolymer and 10-20 %mass graphene PP composite, where the ratio of graphene and PP in graphene-PP composite is 1:9, and the reinforcing masterbatch is graphene-PP-polyethylene terephthalate composite system. USE - Reinforcing masterbatch for BOPP film (claimed). ADVANTAGE - Since PP, PET and graphene are chemically bonded to form molten blend, enhanced reinforcing effect is achieved, and the BOPP film produced by using the reinforcing masterbatch has higher rigidity and ensures increased processing speed. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) preparation method of BOPP film reinforcing masterbatch, which involves (1) surface-modifying graphene by surfactant, drying modified graphene to form stable dispersed modified graphene powder, and blending the modified graphene powder using PP high-speed mixer to obtain uniformly mixed graphene-PP composite material, (2) adding PP graft copolymer to graphene-PP composite, and mechanically blending to form phase solvent blend, (3) uniformly mixing phase solvent blend, homo polypropylene and polyethylene terephthalate (PET), and adding to two-stage extruder connected in series, heating and melting to form melt, and dispersing PET in graphene-PP for forming graphene-PP-PET composite system, injecting supercritical carbon dioxide into front section of second-stage extruder and mixing with melt uniformly, and extruding the foaming and reinforcing masterbatch through die, where the injection volume of supercritical carbon dioxide is 10-50 g/minute, and injection pressure is 15-25 MPa; and (2) a BOPP film, which comprises 10-30 %mass reinforcing masterbatch for BOPP film.