POLYESTER FILM, HEAT-SHRINKABLE LABEL AND PACKAGING CONTAINING IT Russian patent published in 2024 - IPC C08J5/18 C08J7/04 B31D1/02 C08L67/02 

FIELD: packaging.

SUBSTANCE: invention relates to a polyester film used in the field of heat-shrinkable packaging materials. A polyester film is described that contains a polyester resin in which a diol, including ethylene glycol and diethylene glycol, and a dicarboxylic acid are copolymerized, wherein the diol further includes neopentyl glycol, the diethylene glycol content in the diol is from 5 mol.% to 10 mol.%, and the neopentyl glycol content in the diol is 20 mol.% or more, while for a polyester film the difference between the crystallization temperature (T_c) and the melting temperature (T_m) when measured by a differential scanning calorimeter (DSC) is 100°C or less, and the polyester film exhibits an endothermic peak in the range from 100° to 150°C when measured with a differential scanning calorimeter (DSC) after treatment with a 1% aqueous solution of NaOH at 85°C for 15 minutes, and the polyester film is characterized by the difference in reversible heat capacities (ΔC⁰_p), amounting to 0.25 J/g⋅K and more, before and after the glass transition temperature (Tg), measured during the first scan using a differential scanning calorimeter (DSC), from room temperature to 300°C at a temperature increase rate of 3°C/minute, with further cooling, and during the second scanning under the same conditions. A heat-shrinkable label and heat-shrinkable packaging material including polyester film are also described.

EFFECT: providing a film characterized not only by excellent shrinkage with respect to temperature, but also by excellent solvent adhesive strength even when used for gravure printing, UV printing and VSOP printing, making it suitable for use in the process heat shrinkage and seam joining method. In addition, the polyester film can be used in a recycling process due to its ability to demonstrate proper crystal change during NaOH aqueous washing and suppress the occurrence of fusion even after prolonged high-temperature drying.

9 cl, 8 dwg, 3 tbl, 9 ex