The present invention relates to a polyester resin. The polyester resin contains a particular content of diol moieties, derived from isosorbide and diethylene glycol, and thus can provide a resin molded product exhibiting high transparency in spite of a large wall thickness thereof.

The present invention relates to a liquid crystal polyester resin molded article containing a thermoplastic resin comprising a liquid crystal polyester and a fibrous filler, in which the liquid crystal polyester resin molded article contain the fibrous filler in an amount of equal to or greater than 1 part by mass and equal to or smaller than 120 parts by mass with respect to 100 parts by mass of the thermoplastic resin, the proportion of the liquid crystal polyester with respect to 100 mass % of the thermoplastic resin is equal to or greater than 75 mass % and equal to or smaller than 100 mass %, and a length-weighted average fiber length of the fibrous filler is equal to or greater than 0.7 mm.

The present invention relates to a biodegradable resin composition having improved mechanical properties, formability and weatherproof, and a method for manufacturing the biodegradable resin composition. More specifically, the biodegradable resin composition according to the present invention is obtained by mixing an aliphatic dicarboxylic acid or an acid component comprising a mixture of an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid, and aliphatic diol, and subjecting the mixture sequentially to esterification, transesterification, polycondensation, chain extension and solid-state polymerization reactions in the presence of a polyfunctional compound, and may have improved productivity and economic efficiency due to improved reaction rate, excellent tensile strength, elongation rate and processability. In addition, the biodegradable resin composition according to the present invention is environmentally friendly as it is biodegradable in a natural state when buried.

The present invention relates to a biodegradable resin composition having improved mechanical properties, formability and weatherproof, and a method for manufacturing the biodegradable resin composition. More specifically, the biodegradable resin composition according to the present invention is obtained by mixing an aliphatic dicarboxylic acid or an acid component comprising a mixture of an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid, and aliphatic diol, and subjecting the mixture sequentially to esterification, transesterification, polycondensation, chain extension and solid-state polymerization reactions in the presence of a polyfunctional compound, and may have improved productivity and economic efficiency due to improved reaction rate, excellent tensile strength, elongation rate and processability. In addition, the biodegradable resin composition according to the present invention is environmentally friendly as it is biodegradable in a natural state when buried.

The present disclosure provides a copolyester including a dicarboxylic acid component A comprising a terephthalic acid residue or ester-forming derivative thereof, or a mixture thereof, and a 2,4-furandicarboxylic acid residue or ester-forming derivative thereof, or a mixture thereof, and a diol component B comprising an alkanediol residue having from 2 to 22 carbon atoms, wherein the dicarboxylic acid component A has a total molar content, and wherein the 2,4-furandicarboxylic acid residue or ester-forming derivative thereof, is present in an amount of from 0.1 to 10 mol %, with respect to the total molar content of the dicarboxylic acid component A. Inventive copolyesters have a slower crystallization rate, a higher gas barrier to CO.sub.2 and O.sub.2 and a higher ratio of .sup.14C to .sup.12C as measured by ASTM D6866 when compared to a comparable copolyester comprising isophthalic acid instead of 2,4-furandicarboxylic acid.

A method to prepare a polylactic acid-based polymer; the method comprises: —a mixing step, during which lactide monomers, at least one polymerization catalyst and natural origin reactants are mixed together; —a polymerization step, during which the mixture obtained from the previous mixing step is heated at a temperature ranging from 120 to 220° C. in inert atmosphere; and —a cooling step, during which a polymer mass obtained from said polymerization step is cooled down. The natural origin reactants are: (i) a first compound with general formula (I) wherein n ranges from 1 to 20 (ii) a second compound chosen among citric acid, malic acid and derivatives thereof with the carboxylic groups partially or completely in the form of ester or anhydride and with the hydroxyl groups partially or completely in the form of ester.

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A method to prepare a polylactic acid-based polymer; the method comprises: —a mixing step, during which lactide monomers, at least one polymerization catalyst and natural origin reactants are mixed together; —a polymerization step, during which the mixture obtained from the previous mixing step is heated at a temperature ranging from 120 to 220° C. in inert atmosphere; and —a cooling step, during which a polymer mass obtained from said polymerization step is cooled down. The natural origin reactants are: (i) a first compound with general formula (I) wherein n ranges from 1 to 20 (ii) a second compound chosen among citric acid, malic acid and derivatives thereof with the carboxylic groups partially or completely in the form of ester or anhydride and with the hydroxyl groups partially or completely in the form of ester.

##STR00001##

Provided are a polyester resin having high heat resistance and degree of crystallinity, a preparation method thereof, and a resin molded article formed therefrom, the resin molded article having superior heat resistance and mechanical strength and maintaining high transparency.

A process for making a high molecular weight poly(hydroxy acid) polymer having good thermal stability and a weight average molecular weight of >100,000 by GPC. The process includes mixing glycolic acid and/or lactic acid, and a diol or di-acid initiator, and at least one multifunctional initiator to form a liquid monomer mixture in an agitated polycondensation reactor. Polycondensing to form a liquid reaction mixture comprising a pre-polymer having a weight average molecular weight of >10,000 by GPC, and greater than 80% by mole hydroxyl or carboxyl end-group termination, then crystallizing to form a first solid reaction mixture. Then solid state polycondensing the solid reaction mixture to form a solid reaction mixture having a moisture level less than 50 ppm by weight. Then mixing the solid reaction mixture with an appropriate reactive coupling agent in a melting and mixing extruder to couple and form the reaction mixture and form the poly(hydroxy acid) polymer.

A process for making a high molecular weight poly(hydroxy acid) polymer having good thermal stability and a weight average molecular weight of >100,000 by GPC. The process includes mixing glycolic acid and/or lactic acid, and a diol or di-acid initiator, and at least one multifunctional initiator to form a liquid monomer mixture in an agitated polycondensation reactor. Polycondensing to form a liquid reaction mixture comprising a pre-polymer having a weight average molecular weight of >10,000 by GPC, and greater than 80% by mole hydroxyl or carboxyl end-group termination, then crystallizing to form a first solid reaction mixture. Then solid state polycondensing the solid reaction mixture to form a solid reaction mixture having a moisture level less than 50 ppm by weight. Then mixing the solid reaction mixture with an appropriate reactive coupling agent in a melting and mixing extruder to couple and form the reaction mixture and form the poly(hydroxy acid) polymer.