Provided is a method for producing an oligocarbonate polyol devoid of aromatic groups and phenolic functions, comprising a step of polycondensation by transesterification of monomers (A1) and/or dimers (A2) and of diol monomers (B1) and/or of triol monomers (B2), in a particular molar ratio, in order to obtain an oligocarbonate polyol having a molar mass of less than 5000 g/mol and at least two hydroxyl-type chain ends, the monomer (A1) corresponding to the following formula: (A1) and the dimer (A2) corresponding to the following formula: (A2) as well as the oligocarbonate polyol that can be obtained by this method and the polycarbonate that can be obtained by reacting this oligocarbonate with a polyisocyanate. ##STR00001##

Ways of preparing a partially crystalline polycarbonate powder are provided that include dissolving an amorphous polycarbonate in a polar aprotic solvent to form a first solution of solubilized polycarbonate at a first temperature. The first solution is then cooled to a second temperature, the second temperature being lower than the first temperature, where a portion of the solubilized polycarbonate precipitates from the first solution to form a second solution including the partially crystalline polycarbonate powder. Certain partially crystalline polycarbonate powders resulting from such methods are particularly useful in additive manufacturing processes, including powder bed fusion processes.

The present invention relates to a method for selectively separating propylene carbonate by adding water to reaction products comprising a polyether carbonate polyol and propylene carbonate, which are generated from a polymerization reaction of propylene oxide and carbon dioxide under a double metal cyanide (DMC) catalyst, wherein an economical and effective separation of propylene carbonate can be achieved.

The invention relates to a method for producing an oligocarbonate polyol devoid of aromatic groups and phenolic functions, comprising a step of polycondensation by transesterification of monomers (A1) and/or dimers (A2) and of diol monomers (B1) and/or of triol monomers (B2), in a particular molar ratio, in order to obtain an oligocarbonate polyol having a molar mass of less than 5000 g/mol and at least two hydroxyl-type chain ends, the monomer (A1) corresponding to the following formula: (A1) and the dimer (A2) corresponding to the following formula: (A2) as well as the oligocarbonate polyol that can be obtained by this method and the polycarbonate that can be obtained by reacting this oligocarbonate with a polyisocyanate.

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The purpose of the present invention is to provide an aromatic polycarbonate oligomer solid which has a markedly reduced amount of a low molecular weight component, has no or a markedly reduced amount of chlorine-containing compounds, has a high loose bulk density and is easy to handle. The purpose is met by an aromatic polycarbonate oligomer solid which includes a repeating unit represented by general formula (1), has a weight average molecular weight of 500 to 10000, has a low molecular weight component of less than or equal to 5.0 area % as measured by high performance liquid chromatography, and has a loose bulk density of greater than or equal to 0.20 g/cm.sup.3. ##STR00001##

The present invention relates to a production method of polyalkylene carbonate particles capable of precipitating and separating resin particles from a polyalkylene carbonate suspension obtained through polymerization of an epoxide and carbon dioxide. According to the present invention, the production method is capable of obtaining a polyalkylene carbonate resin having excellent workability with a high yield and a low energy cost while reducing a scale of a facility, a processing time, and a wastewater amount, as compared to conventional methods such as a flash separation method.

The present invention relates to a method for selectively separating propylene carbonate by adding water to reaction products comprising a polyether carbonate polyol and propylene carbonate, which are generated from a polymerization reaction of propylene oxide and carbon dioxide under a double metal cyanide (DMC) catalyst, wherein an economical and effective separation of propylene carbonate can be achieved.

The purpose of the present invention is to provide an aromatic polycarbonate oligomer solid which has a markedly reduced amount of a low molecular weight component, has no or a markedly reduced amount of chlorine-containing compounds, has a high loose bulk density and is easy to handle. The purpose is met by an aromatic polycarbonate oligomer solid which includes a repeating unit represented by general formula (1), has a weight average molecular weight of 500 to 10000, has a low molecular weight component of less than or equal to 5.0 area % as measured by high performance liquid chromatography, and has a loose bulk density of greater than or equal to 0.20 g/cm.sup.3.

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The present invention relates to polyester polyols made from aromatic polyacid sources such as thermoplastic polyesters. The polyols can be made by heating a thermoplastic polyester such as virgin polyethylene terephthalate, recycled polyethylene terephthalate, or mixtures thereof, with a glycol to give a digested intermediate which is then reacted with a digestible polymer, which can be obtained from various recycle waste streams. The polyester polyols comprise a glycol-digested polyacid source and a further digestible polymer. The polyester polyols provide a sustainable alternative to petrochemical or biochemical based polyester polyols.

Ways of preparing a partially crystalline polycarbonate powder are provided that include dissolving an amorphous polycarbonate in a polar aprotic solvent to form a first solution of solubilized polycarbonate at a first temperature. The first solution is then cooled to a second temperature, the second temperature being lower than the first temperature, where a portion of the solubilized polycarbonate precipitates from the first solution to form a second solution including the partially crystalline polycarbonate powder. Certain partially crystalline polycarbonate powders resulting from such methods are particularly useful in additive manufacturing processes, including powder bed fusion processes.