Abstract: The present invention provides a method of producing a polyethylene terephthalate graft copolymerized resin, comprising subjecting the following mixture to a homogeneous reaction at a temperature of 250° C. or higher to impart a high melt viscosity to the mixture, the mixture containing (A) 100 parts by weight of a polyethylene terephthalate polyester as a main material, (B) 0.01 to 2 parts by weight of a polymeric polyfunctional epoxy compound containing 7 to 100 epoxy groups in a molecule and having a molecular weight of 1,000 to 300,000 as a coupling agent, (C) 0.01 to 1 part by weight of a metal salt of an organic acid as a coupling reaction catalyst, and (D) 0 to 100 parts by weight of an aromatic alicyclic polyester and/or an aromatic aliphatic polyester each having a carboxyl group in an aromatic nucleus as an auxiliary material.

Abstract: The present invention provides a method of manufacturing high-melting-tension heat-resistant transparent or opaque sheets, boards, and molds from polyethylene terephthalate (PET). The method is characterized in that a mixture of: (1) PET polyester whose melt flow rate (MFR) is 45-130 g/10 minutes (a); (2) coupling agent master batch (f) comprising coupling agent (d) and substrate (e), wherein coupling agent (d) is a mixture of compounds containing 2 epoxy groups (b) and compounds containing 3 or more epoxy groups (c); and (3) catalyst master batch (i) comprising coupling reaction catalyst (g) and substrate (h); is melted in a reaction-extruder to give PET polyester whose MFR is 40 g/10 minutes or less.

Abstract: The present invention provides a masterbatch method for producing a polyester resin and articles thereof; comprising reacting following materials uniformly at a temperature equal to or greater than the melting point of a polyester, the materials comprising: (1) 100 parts by weight of saturated straight-chain polyester A; (2) 1 to 10 parts by weight of binder masterbatch D comprising: a mixture containing a compound having two epoxy groups and a compound having an average number of epoxy groups of 2.1 or more; (3) 0.25 to 10 parts by weight of catalyst masterbatch G comprising: a metal carboxylate, whereby the melt viscosity of the polyester increases so that the melt flow rate (MFR) becomes 50 g/10 min or less, and the degree of swelling of the polyester increases to between 5% and 200%, thus resulting in a high-quality resin having excellent mechanical properties. The resin can be advantageously used for films, sheets, foamed materials, pipes, cushioning, heat insulators, packing materials, and so forth.