Provided is an aqueous coating composition which has excellent storage stability and whereby high coating film performance in terms of hardness, water resistance, etc., can be exhibited even when the aqueous coating composition is cured at a relatively low temperature. Disclosed is an aqueous coating composition which contains (A) a resin containing hydroxyl groups and carboxyl groups, (B) a blocked polyisocyanate compound, (C) a phosphate-group-containing compound, and (D) a basic compound, and which has a pH in the range of 7.0-8.2, wherein the basic compound (D) contains a specific quantity of (D1) a basic compound which has an acid dissociation constant (PKa) in the range of 7.0-8.5 and a boiling point in the range of 100-200° C.

Provided is an aqueous coating composition which has excellent storage stability and whereby high coating film performance in terms of hardness, water resistance, etc., can be exhibited even when the aqueous coating composition is cured at a relatively low temperature. Disclosed is an aqueous coating composition which contains (A) a resin containing hydroxyl groups and carboxyl groups, (B) a blocked polyisocyanate compound, (C) a phosphate-group-containing compound, and (D) a basic compound, and which has a pH in the range of 7.0-8.2, wherein the basic compound (D) contains a specific quantity of (D1) a basic compound which has an acid dissociation constant (PKa) in the range of 7.0-8.5 and a boiling point in the range of 100-200° C.

A method for improving L* color of polyethylene terephthalate polymer, the method including bis-hydroxylethyl-eneterephthalate being polycondensed to produce said polyethylene terephthalate polymer in a polyethylene terephthalate manufacturing process, and wherein said process requires an antimony-containing catalyst, the method comprising the steps of: i) adding said antimony-containing catalyst at a temperature in a range of a melting point of said BHET to an upper temperature of 220° C.; and ii) exposing said BHET in a molten state to glycol removal before addition of said antimony-containing catalyst.

A method for improving L* color of polyethylene terephthalate polymer, the method including bis-hydroxylethyl-eneterephthalate being polycondensed to produce said polyethylene terephthalate polymer in a polyethylene terephthalate manufacturing process, and wherein said process requires an antimony-containing catalyst, the method comprising the steps of: i) adding said antimony-containing catalyst at a temperature in a range of a melting point of said BHET to an upper temperature of 220° C.; and ii) exposing said BHET in a molten state to glycol removal before addition of said antimony-containing catalyst.

The polyester copolymer according to the present disclosure is excellent in processability, particularly in shear thinning characteristics, and thus can be applied to the production of various transparent containers by an EBM process.

The polyester copolymer according to the present disclosure is excellent in processability, particularly in shear thinning characteristics, and thus can be applied to the production of various transparent containers by an EBM process.

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.

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.

[Problem] The present invention aims to provide a high-molecular-weight modified copolymerized polyester resin that has a reactive functional group at a site other than the terminals of the molecular chain thereof, has an excellent reactivity with a curing agent (such as an epoxy resin or an isocyanate compound), and can be used to form an organic-solvent-and-emulsifier-free water dispersion having excellent storage stability.

[Solution] A modified copolymerized polyester resin (B) having a structure in which a copolymerized polyester resin (A) has an unsaturated polyvalent carboxylic acid added to a side chain thereof, and the copolymerized polyester resin (A) contains, as copolymerization components, at least one member selected from the group consisting of: a copolymerization component having an alicyclic structure (component x); a copolymerization component having six or more continuous methylene groups (component y); and an acyclic aliphatic copolymerization component having a tertiary carbon atom and a molecular weight of more than 100 (component z).

[Problem] The present invention aims to provide a high-molecular-weight modified copolymerized polyester resin that has a reactive functional group at a site other than the terminals of the molecular chain thereof, has an excellent reactivity with a curing agent (such as an epoxy resin or an isocyanate compound), and can be used to form an organic-solvent-and-emulsifier-free water dispersion having excellent storage stability.

[Solution] A modified copolymerized polyester resin (B) having a structure in which a copolymerized polyester resin (A) has an unsaturated polyvalent carboxylic acid added to a side chain thereof, and the copolymerized polyester resin (A) contains, as copolymerization components, at least one member selected from the group consisting of: a copolymerization component having an alicyclic structure (component x); a copolymerization component having six or more continuous methylene groups (component y); and an acyclic aliphatic copolymerization component having a tertiary carbon atom and a molecular weight of more than 100 (component z).