A shrink film comprising a core layer comprising a glycol modified polyester, the core having an upper and lower surface; an upper skin layer disposed on the upper surface of the core layer and a lower skin layer disposed on the lower surface of the core layer, the skin layers each individually comprising (a) a resin material; and (b) an antiblocking agent.

An object is to provide a laminate having excellent lamination strength that includes a polyester film having a furandicarboxylate unit and a heat-sealable resin layer, and to provide a packaging bag including the same. A laminate including a polyester film and a heat-sealable resin layer, wherein the polyester film is a biaxially oriented polyester film containing a polyethylene furandicarboxylate resin composed of a furandicarboxylic acid and ethylene glycol, a plane orientation coefficient P of the film is 0.005 or more and 0.200 or less, a thickness of the film is 1 m or more and 300 m or less, a heat shrinkage rate of the film is 10% or less when heated at 150 C. for 30 minutes, and lamination strength of the laminate is 2.0 N/15 mm or more.

The present invention relates to an alkyd resin comprising the condensation product of at least the following components (A) a polybasic acid, (B) a polyhydric alcohol, and (C) a linear C.sub.12-C.sub.60 hydrocarbo monocarboxylic acid, and optionally (D) at least one component other than any of components A to C characterized in that at least a part of the polybasic acid (A) is a (optionally hydrogenated) Diels Alder adduct of citraconic acid with C.sub.4-C.sub.14 conjugated diene, a (optionally hydrogenated) Diels Alder adduct of citraconic anhydride with C.sub.4-C.sub.14 conjugated diene, a half ester of such a Diels Alder adduct and/or a diester of such a Diels Alder adduct.

The present invention relates to an alkyd resin comprising the condensation product of at least the following components (A) a polybasic acid, (B) a polyhydric alcohol, and (C) a linear C.sub.12-C.sub.60 hydrocarbo monocarboxylic acid, and optionally (D) at least one component other than any of components A to C characterized in that at least a part of the polybasic acid (A) is a (optionally hydrogenated) Diels Alder adduct of citraconic acid with C.sub.4-C.sub.14 conjugated diene, a (optionally hydrogenated) Diels Alder adduct of citraconic anhydride with C.sub.4-C.sub.14 conjugated diene, a half ester of such a Diels Alder adduct and/or a diester of such a Diels Alder adduct.

The polyester sheet in accordance with an aspect of the present invention contains crystals of polyester which is a polycondensate of polyvalent carboxylic acid and polyalcohol. The polyester sheet contains nano-oriented crystals which contain crystals of polyester in each of which a polymer chain is highly oriented and each of which has a crystal size of 50 nm or less. A heatproof temperature of the polyester sheet is higher than a temperature that is lower than an equilibrium melting point of the polyester by 80 C., and a melting point of the polyester sheet is higher than a temperature that is lower than the equilibrium melting point of the polyester by 40 C.

The polyester sheet in accordance with an aspect of the present invention contains crystals of polyester which is a polycondensate of polyvalent carboxylic acid and polyalcohol. The polyester sheet contains nano-oriented crystals which contain crystals of polyester in each of which a polymer chain is highly oriented and each of which has a crystal size of 50 nm or less. A heatproof temperature of the polyester sheet is higher than a temperature that is lower than an equilibrium melting point of the polyester by 80 C., and a melting point of the polyester sheet is higher than a temperature that is lower than the equilibrium melting point of the polyester by 40 C.

The present invention relates to amorphous polyesters on the basis of betulin, a method for producing them and their use.

A heat-shrinkable polyester-based film is provided, which is heat-shrinkable in the longitudinal direction and which is freed from various problems, particularly curling-up or peeling in a bonded area. The heat-shrinkable polyester-based film is characterized by an A1/A2 (absorbance) ratio in the longitudinal direction, which is the main shrinking direction of the film, of 0.55 to 1, with an A1/A2 ratio in the width direction perpendicular to the main shrinking direction of 0.5 to 0.9, wherein A1 is the absorbance of the film at 1340 cm.sup.1 and A2 is the absorbance of the film at 1410 cm.sup.1 as determined by polarized ATR-FTIR spectroscopy, and a hot-water shrinkage of 35 to 60% in the longitudinal direction of the film and 3 to 12% in the width direction of the film, wherein the hot-water shrinkage is determined by dipping the film in hot water at 90 C. for 10 seconds.

A heat-shrinkable polyester-based film is provided, which is heat-shrinkable in the longitudinal direction and which is freed from various problems, particularly curling-up or peeling in a bonded area. The heat-shrinkable polyester-based film is characterized by an A1/A2 (absorbance) ratio in the longitudinal direction, which is the main shrinking direction of the film, of 0.55 to 1, with an A1/A2 ratio in the width direction perpendicular to the main shrinking direction of 0.5 to 0.9, wherein A1 is the absorbance of the film at 1340 cm.sup.1 and A2 is the absorbance of the film at 1410 cm.sup.1 as determined by polarized ATR-FTIR spectroscopy, and a hot-water shrinkage of 35 to 60% in the longitudinal direction of the film and 3 to 12% in the width direction of the film, wherein the hot-water shrinkage is determined by dipping the film in hot water at 90 C. for 10 seconds.

A polyester resin composition containing: a polyester resin containing a unit (A) represented by the following general formula (1); and an antioxidant: ##STR00001##
wherein R.sub.1 is a hydrogen atom, CH.sub.3 or C.sub.2H.sub.5, R.sub.2 and R.sub.3 are each independently a hydrogen atom or CH.sub.3, and n is 0 or 1.