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.

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.

Aspects of the present invention concern the ring-opening copolymerization (ROCOP) of aromatic anhydrides and epoxides, such as terpene oxides, using sustainable starting materials, as well as the resulting polyester products having an unusually high glass transition temperature and low dispersity.

A polyarylate resin includes repeating units represented by formulas (1), (2), (3), and (4). A percentage of the number of repeats of the repeating unit represented by formula (3) relative to the total number of repeats of the respective repeating units represented by formulas (1) and (3) is greater than 0% and less than 20%. In formula (1), R.sup.1 and R.sup.2 each represent, independently of one another, a hydrogen atom or a methyl group and X represents a divalent group represented by formula (X1) or (X2). In formula (2), W represents, a divalent group represented by formula (W1) or (W2).

##STR00001##

A polyarylate resin includes repeating units represented by formulas (1), (2), (3), and (4). A percentage of the number of repeats of the repeating unit represented by formula (3) relative to the total number of repeats of the respective repeating units represented by formulas (1) and (3) is greater than 0% and less than 20%. In formula (1), R.sup.1 and R.sup.2 each represent, independently of one another, a hydrogen atom or a methyl group and X represents a divalent group represented by formula (X1) or (X2). In formula (2), W represents, a divalent group represented by formula (W1) or (W2).

##STR00001##

An electrophotographic photosensitive member (1) includes a conductive substrate (2) and a photosensitive layer (3). The photosensitive layer (3) is a single-layer photosensitive layer (3c) and contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The binder resin includes a polyarylate resin represented by general formula (1).

##STR00001##

In general formula (1), Q.sup.1, Q.sup.2, Q.sup.3, and Q.sup.4 each represent a methyl group or a hydrogen atom. r, s, t, and u each represent a number greater than or equal to 15 and less than or equal to 35. X and Y each represent a divalent group represented by chemical formula (2A), chemical formula (2B), chemical formula (2C), or chemical formula (2D), and X and Y are different from each other

##STR00002##

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.

A resin composed of a particular polymer, the particular polymer including a repeating unit containing a structure derived from a dehydroabietic acid, a specific structural unit, and a specific aromatic ring-containing structural unit in the main chain.

A resin composed of a particular polymer, the particular polymer including a repeating unit containing a structure derived from a dehydroabietic acid, a specific structural unit, and a specific aromatic ring-containing structural unit in the main chain.