The present invention provides a polycarbonate copolymer having low specific gravity and high surface hardness. The polycarbonate copolymer of the present invention contains a unit (A) represented by the following formula (1-1) or (1-2) and a unit (B) represented by the following formula (3); wherein in formula (1-1), R.sub.1 and R.sub.2 respectively and independently represent a hydrogen atom, hydrocarbon group having 1 to 10 carbon atoms that may contain an aromatic group, or halogen atom, and Y represents a divalent organic residue comprised of the following formula (2); in formula (2), C.sub.m represents a cycloalkylene group, m represents an integer of 3 to 20, R.sub.3 represents a hydrogen atom, halogen atom, alkyl group having 1 to 20 carbon atoms or cycloalkyl group having 3 to 20 carbon atoms, and n represents an integer of 1 to 10; in formula (1-2), R.sub.1 and R.sub.2 respectively and independently represent a hydrogen atom, hydrocarbon group having 1 to 10 carbon atoms that may contain an aromatic group or a halogen atom, and W represents a single bond, carbon atom, oxygen atom or sulfur atom; and in formula (3), R.sub.4, R.sub.5, R.sub.6 and R.sub.7 respectively and independently represent a hydrogen atom, halogen atom, alkyl group having 1 to 20 carbon atoms or cycloalkyl group having 3 to 20 carbon atoms:

##STR00001##

An interfacial process for preparing a poly(aliphatic ester-carbonate) includes providing an initial polymerization reaction mixture comprising an aliphatic C6-20 dicarboxylic acid, a bisphenol, an alkali hydroxide, and optionally a catalyst in a solvent system comprising water and an immiscible organic solvent, adding an initial portion of a carbonyl dihalide over a first time period while maintaining the reaction at a first pH from 7 to 8; and adding a second portion of the carbonyl dihalide over a second, subsequent time period while maintaining the reaction pH at a second pH from 9 to 12, to provide a product polymerization mixture, wherein the amount of alkali hydroxide in the initial polymerization reaction mixture is effective to increase the fraction of the first time period at a measured pH of 7 to 8 compared to the same reaction mixture with a higher amount of alkali hydroxide in the initial polymerization mixture.

The present invention provides new classes of phenolic compounds derived from hydroxyacids and tyrosol or tyrosol analogues, useful as monomers for preparation of biocompatible polymers, and the biocompatible polymers prepared from these monomeric hydroxyacid-phenolic compounds, including novel biodegradable and/or bioresorbable polymers. These biocompatible polymers or polymer compositions with enhanced bioresorbabilty and processability are useful in a variety of medical applications, such as in medical devices and controlled-release therapeutic formulations. The invention also provides methods for preparing these monomeric hydroxyacid-phenolic compounds and biocompatible polymers.

According to one embodiment, a polyester resin is provided, which includes a structural unit derived from a compound represented by general formula (1), a structural unit derived from a compound represented by general formula (2), and a structural unit derived from a dicarboxylic acid or a derivative thereof. ##STR00001##

The present invention makes it possible to provide a polycarbonate copolymer including structural units represented by general formula (K) and structural units represented by general formula (1). ##STR00001##
(In general formula (K), R represents H, CH.sub.3 or CH.sub.2CH.sub.3.) ##STR00002##
(In general formula (1), Q represents a C5 or higher aliphatic hydrocarbon group optionally including a hetero atom.).

According to one embodiment, a polyester resin is provided, which includes a structural unit derived from a compound represented by general formula (1), a structural unit derived from a compound represented by general formula (2), and a structural unit derived from a dicarboxylic acid or a derivative thereof.

##STR00001##

A filament for use in forming a support structure in fused filament fabrication, the filament comprising an amorphous, thermoplastic resin further comprising Bisphenol Isophorone carbonate units and Bisphenol A carbonate units, wherein the Bisphenol Isophorone carbonate units are 30 to 50 mole percent of the total of Bisphenol A carbonate units and Bisphenol Isophorone carbonate units in the resin, and wherein the resin has a glass transition temperature from 165 C. to 200 C. The composition used to form the support filament exhibits a desirable combination of filament formability, printability, lack of significant oozing from the printer nozzle, and good ease of mechanical separation from the build material at room temperature after printing.

An object of the present invention is to provide a phase difference film that can exhibit sufficient reciprocal wavelength dispersibility. The present invention includes a copolymer containing at least one selected from a unit represented by Formula (1) and a unit represented by Formula (2), and a unit represented by Formula (3), in which 20 nm<Re (548)<300 nm, 0.5<Re (446)/Re (548)<1.0, and 1.0<Re (629)/Re (548)<2.0. Here, Re (446), Re (548), and Re (629) represent in-plane retardations at wavelengths of 446 nm, 548 nm, and 629 nm, respectively.

A phase difference film and a circularly polarizing film each achieve suppressed coloration when viewed from the front direction, a smaller difference in tint between views from the front direction and the oblique direction, and suppressed image unevenness, where the film is applied to an image display panel, in particular, an organic EL panel; as well as an image display device including the circularly polarizing film. The phase difference film includes optically anisotropic layers A and B, in which a retardation RthA of layer A in the thickness direction at a wavelength of 550 nm is larger than 0, layer A exhibits predetermined optical properties, a retardation RthB of layer B in the thickness direction at a wavelength of 550 nm is smaller than 0, layer B satisfies predetermined optical properties, and the angle formed between a slow axis of the optically anisotropic layers A and B is 9010.

A foamable poly carbonate composition comprising 5 to 95 wt % of a poly(siloxane) block copolymer comprising a poly(carbonate-siloxane) comprising 50 to 99 wt % of bisphenol A carbonate units and 1 to 50 wt % of dimethylsiloxane units, each based on the weight of the poly(carbonate-siloxane), a poly(ester-carbonate-siloxane) comprising bisphenol A carbonate units, isophthalate-terephthalate-bisphenol A ester units, and 5 to 200 dimethyl siloxane units, or a combination thereof; 5 to 95 wt % of an auxiliary component comprising a poly(alkylene ester), a poly(ester-carbonate), or a combination thereof, and optionally, a homopolycarbonate; optionally, up to 10 wt % of an additive composition, wherein the composition has a glass transition temperature of 140 C. and below measured using differential scanning calorimetry, and wherein a foamed sample of the composition has an average cell size of 10 nanometers to 20 micrometers.