POLYESTER FILM AND METHOD FOR REPRODUCING POLYESTER CONTAINER USING SAME Russian patent published in 2023 - IPC C08J5/18 C08L67/02 C08J11/04 B29B17/04 B29B9/12 B29C48/08 

FIELD: polymers.

SUBSTANCE: group of inventions relates to a polyester film, to a method for its production and to a method for regenerating a polyethylene terephthalate (PET) container in which it is used. A polyester film is used as a heat shrink label for a polyethylene terephthalate (PET) container, wherein the polyester film includes a copolymerized polyester resin in which a diol and a dicarboxylic acid are copolymerized, the diol contains ethylene glycol, neopentyl glycol and diethylene glycol, and the dicarboxylic acid contains terephthalic acid. The polyester film also contains a homopolyethylene terephthalate (HOMO-PET) resin in an amount of 0.5 to 37% by mass based on the total weight of the copolymerized polyester resin and the homopolyethylene terephthalate resin, with the enthalpy of melting (ΔHm) of the polyester film measured by differential scanning calorimetry is greater than or equal to 9 J/g, and the clumping degree of the polyester film is 10% or less. Meanwhile, the polyester film has a peel strength of 150 gf/3cm or more, modified by a measurement method in which two sheets of resin film, namely a first polyester film and a second polyester film, are applied to one side of the first polyester film 1.3-dioxolane in the form of a strip 2 mm wide and 30 mm long to form an adhesive area, the second polyester film is laminated with the first polyester film on which the adhesive area was formed, a pressure of 160 Pa is applied to the adhesive area for 1 hour for aging, and the maximum strength as peel strength is measured when the first and second polyester films are delaminated at a speed of 300 mm/min at an angle of 180°.

EFFECT: providing a polyester film characterized by improved thermal and chemical characteristics, namely, an excellent degree of shrinkage depending on temperature and adhesive strength, including when exposed to a solvent, even when used for gravure printing, UV-curable printing and variable-size offset printing (VSOP), which makes it suitable for the shrink process and sealing process, while the film is suitable for reuse due to controlled crystallinity, inhomogeneous clumping rarely occurs, even with long heat treatment in the regeneration process.

7 cl, 5 dwg, 5 tbl, 36 ex