A thermosetting composition having: I) an unsaturated curable polyester comprising the residues of an ,-unsaturated polycarboxylic acid compound, said ,-unsaturated polycarboxylic acid compound having at least two carboxylic acid groups or at least one anhydride group, and having at least one unsaturation in a position that is , relative to a carbonyl group and not located on an aromatic ring; and II) a phenolic resin having at least one methylol group. The unsaturated curable polyester resin can be dispersed in water or dissolved in a solvent and is suitable for waterborne or solventborne coating compositions. Phenolic based crosslinking coating compositions that contain these unsaturated curable polyester resins are curable at elevated temperatures.

Described are shape memory polymers and methods of making shape memory polymers and actuators from the shape memory polymers.

A composition with improved adhesive and sealant properties comprises a) a pre-polymer comprising a polymeric unit of the general formula (-A-B-).sub.n, wherein A represents a substituted or un-substituted ester, B represents a substituted or un-substituted acid ester comprising at least two acid ester functionalities, and n represents an integer greater than 1; wherein the content of grafted anhydride in the composition is less than 0.05 mol/mol of polyacid.

A heat-shrinkable polyester film comprising an ethylene terephthalate unit as a main component, wherein the film satisfies the following requirements (1) to (4): (1) a loop stiffness in a width direction of the film is 6 mN/25 mm or more and 200 mN/25 mm or less; (2) a heat shrinkage ratio in the width direction of the film by immersion in hot water at 80 C. for 10 seconds is 20% or more and 70% or less; (3) when one surface and the other surface of the film is heat sealed at a temperature of 140 C., at a pressure of 0.1 MPa for 1 second, a strength by shear lap peeling test in the width direction of the film is 20 N/15 mm or more and 80 N/15 mm or less; and, (4) at least one topmost surface layer has a wetting tension of 40 mN/m or more and 55 mN/m or less.

The present invention relates to a process for depolymerising polyethylene terephthalate (PET), in which method PET is reacted with sodium glycolate or potassium glycolate, which has been obtained by reactive distillation, to form a mixture M.sub.1 including Bis(2-hydroxyethyl) terephthalate (BHET). The process according to the invention is distinguished by the fact that BHET makes up a particularly high proportion of the decomposition products in the mixture M.sub.1. The process according to the invention thus provides a high yield of BHET that can be used directly for producing PET again. The present invention thus also relates to a process for recycling PET, in which the BHET obtained in the process for depolymerising PET is polymerised again to form PET, optionally after being further purified from M.sub.1.

Provided is a copolymer having polyester and polyether structures and exhibiting high level of degradability by external stimuli such as light, preferably a polyester-polyether copolymer having at least two radical polymerizable unsaturated groups per molecule; an elastomer spherical particle composed of the copolymers as structural units, and methods of producing these. Also provided are a copolymer having a polyester structure and a polyether structure; and an elastomer spherical particle composed of a polymer containing structural units originated from the copolymer having a polyester structure and a polyether structure, wherein the spherical particle has a volume-average particle diameter of 0.5 to 200 m.