The invention relates to a process of preparing a glycolide product from methyl polyglycolate or its product. The process comprises depolymerizing the methyl polyglycolate or its product in the presence of a depolymerization agent to make a depolymerized product; repolymerizing the depolymerized product to make a glycolic acid oligomer; and pyrolyzing the repolymerized mixture to make a glycolide product. A rare earth metal catalyst may be used facilitate the depolymerization reaction. The glycolide pyrolysis conversion rate may be greater than 90%. Also provided are related glycolide product and the glycolic acid oligomer. The glycolic acid oligomer may have a weight average molecular weight of 4,000-80,000.

A method for producing a bisphenol or the like by using a chemical recycling method that is moderate, has a small environmental load, and can efficiently degrade a polycarbonate resin is provided. In addition, a method for producing a recycled polycarbonate resin or the like by using a useful substance such as the bisphenol or the like is provided. A method for producing a bisphenol, including degrading a polycarbonate resin in the presence of an aromatic monoalcohol, water, and a catalyst. A method for producing carbon dioxide, including recovering carbon dioxide generated by the method for producing a bisphenol. A method for producing a carbonic acid diester by using the carbon dioxide. A method for producing a recycled polycarbonate resin by using the bisphenol and/or the carbonic acid diester. A method for producing an epoxy resin and a method for producing an epoxy resin cured product, by using the bisphenol

A method for producing a bisphenol or the like by using a chemical recycling method that is moderate, has a small environmental load, and can efficiently degrade a polycarbonate resin is provided. In addition, a method for producing a recycled polycarbonate resin or the like by using a useful substance such as the bisphenol or the like is provided. A method for producing a bisphenol, including degrading a polycarbonate resin in the presence of an aromatic monoalcohol, water, and a catalyst. A method for producing carbon dioxide, including recovering carbon dioxide generated by the method for producing a bisphenol. A method for producing a carbonic acid diester by using the carbon dioxide. A method for producing a recycled polycarbonate resin by using the bisphenol and/or the carbonic acid diester. A method for producing an epoxy resin and a method for producing an epoxy resin cured product, by using the bisphenol

A method for rotary die cutting. The method may include providing, to an accumulator, an input comprising a melt. The method may include processing, by the accumulator utilizing a set of rolls, the melt to form a sheet of material. The method may include providing, from the accumulator, the sheet of material to a dandy roll. The method may include providing, from the dandy roll, the sheet of material to a rotary die. The method may include cutting, by the rotary die, a product from the sheet of material. The method may include providing, from the rotary die, the product to a stacker.

A method for rotary die cutting. The method may include providing, to an accumulator, an input comprising a melt. The method may include processing, by the accumulator utilizing a set of rolls, the melt to form a sheet of material. The method may include providing, from the accumulator, the sheet of material to a dandy roll. The method may include providing, from the dandy roll, the sheet of material to a rotary die. The method may include cutting, by the rotary die, a product from the sheet of material. The method may include providing, from the rotary die, the product to a stacker.

The present disclosure relates to a depolymerization method of a polymer comprising an ester functional group with or without pigments or dyes, a composition for the depolymerization, and a purification method for selectively separating foreign substances from a monomer of the polymer, and is characterized in that a compound represented by formula 1 is added as an additive. The depolymerization method according to the present disclosure enables depolymerization at low temperatures and may increase the yield of a target product. In addition, the purification method according to the present disclosure may remove foreign substances including pigments or dyes from a monomer of the polymer to prepare high-purity monomers.

A process for depolymerizing a polyethylene terephthalate (PET) by glycolysis with ethylene glycol (EG) is described. Also described is a plant for carrying out the process. The PET is first mixed in the solid state with EG at a temperature of 60-120° C. to form a heterogeneous mixture with an EG:PET weight ratio of 0.1-3.0, and is then pressed to squeeze out an aliquot of EG. The compressed mixture is fed to a reactor, where the mixture is heated and kept under mixing at a temperature of 170-270° C., with an EG:PET weight ratio of 0.1-4.0, to glycolize the PET and obtain a glycolyzed product containing bis(2-hydroxyethyl) terephthalate and/or oligomers thereof. The process is advantageous in treating waste PET as such and reducing the EG to PET ratio necessary for glycolysis that allows the reaction to be carried out at relatively high temperatures of 230° C. and above to expedite the process.

A process for depolymerizing a polyethylene terephthalate (PET) by glycolysis with ethylene glycol (EG) is described. Also described is a plant for carrying out the process. The PET is first mixed in the solid state with EG at a temperature of 60-120° C. to form a heterogeneous mixture with an EG:PET weight ratio of 0.1-3.0, and is then pressed to squeeze out an aliquot of EG. The compressed mixture is fed to a reactor, where the mixture is heated and kept under mixing at a temperature of 170-270° C., with an EG:PET weight ratio of 0.1-4.0, to glycolize the PET and obtain a glycolyzed product containing bis(2-hydroxyethyl) terephthalate and/or oligomers thereof. The process is advantageous in treating waste PET as such and reducing the EG to PET ratio necessary for glycolysis that allows the reaction to be carried out at relatively high temperatures of 230° C. and above to expedite the process.

The invention present invention belongs to waste polyester recycling technology field and relates to a method and a device for recycling waste polyester, in particular to a method and a device for recycling waste polyester by modified chemical method to recover waste polyester to prepare dimethyl terephthalate (DMT). The recycling method of the present invention uses a process of continuous feeding, continuous alcoholysis and continuous transesterification. It can make the material undergo homogeneous alcoholysis in the melted state, and the required alcoholysis time is short. Because more than two alcoholysis tanks are used in series for continuous alcoholysis, the product quality of alcoholysis product is stable. When the alcoholysis product is continuously transesterified, it avoids the occurrence of side reactions and the unstable quality of the transesterified product, and the purity and yield of recycling product of waste polyester are greatly improved.

Various methods of reshaping and recycling thermoset polymers and composites containing thermoset polymers are provided. The methods involve the bond exchange reaction of exchangeable covalent bonds in the polymer matrix with a suitable small molecule solvent in the presence of a catalyst. In some aspects, the methods are applied to a carbon fiber reinforced polymer or a thermoset polymer where the thermoset polymer matrix includes a plurality of ester bonds. Using a small molecule alcohol, the methods provide for recycling one or both of the carbon fiber and the polymer, for welding two surfaces, or for repairing a damaged surface in the materials.