Production process of recycling plastics chemically degrading the recycling plastics and adding several diacids for an esterification reaction

This invention relates to a production process of recycling polyester plastics and a re-manufactured product. Waste PET bottles or waste yarns and the like are chemically degraded and then polymerized, and can be recycled in low cost to be used as a resin raw material or white material. After the recycling plastics (PET) are degraded to a certain extent, several diacids are added for an esterification reaction until the reaction reaches a specific molecular weight of 1000-3000. They can be further used for solvent-based PU and water-based PUD polymerization or used as other polyesters or polyether polyols in foam formulations. According to this invention, the waste PET bottles or waste yarns and the like after recycling can be used as raw materials and reprocessed for industrial application, which not only has high recovery rate and low cost but also has an industrial application value. It is actually a novel technology for environmental protection and recycling of plastics.