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 invention pertains generally to paints containing a binder curable by an autoxidation mechanism and at least one drier comprising a sulfonate compound of vanadium of formula (VII)

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where R.sup.1 and R.sup.2 are independently selected from a group involving hydrogen, C.sub.1-C.sub.12 alkyl, C.sub.1-C.sub.12 halogenated alkyl, C.sub.6-C.sub.10 aryl, benzyl; and whereas aryl and benzyl can be optionally substituted by up to three substituents independently selected from a group involving C.sub.1-C.sub.20 alkyl, and hydroxy(C.sub.1-C.sub.2)alkyl.

The invention pertains generally to paints containing a binder curable by an autoxidation mechanism and at least one drier comprising a sulfonate compound of vanadium of formula (VII)

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where R.sup.1 and R.sup.2 are independently selected from a group involving hydrogen, C.sub.1-C.sub.12 alkyl, C.sub.1-C.sub.12 halogenated alkyl, C.sub.6-C.sub.10 aryl, benzyl; and whereas aryl and benzyl can be optionally substituted by up to three substituents independently selected from a group involving C.sub.1-C.sub.20 alkyl, and hydroxy(C.sub.1-C.sub.2)alkyl.

Provided are a tricyclodecane dimethanol composition which may be usefully applied to the preparation of a high heat resistant polyester by reducing the content of impurities, and a preparation method thereof.

Provided are a tricyclodecane dimethanol composition which may be usefully applied to the preparation of a high heat resistant polyester by reducing the content of impurities, and a preparation method thereof.

Provided are a tricyclodecane dimethanol composition which may be suitably used in preparing a polyester resin exhibiting excellent solvent resistance and chemical resistance when forming a coating film and having excellent solubility in organic solvents or water, and a preparation method thereof.

A titanium catalyst and a synthesizing method of polyester resins are provided in the present disclosure. The titanium catalyst has a chemical structure represented by Formula (I), Formula (II) or Formula (III).

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The symbols shown in the Formula (I), the Formula (II) or the Formula (III) are defined in the description. The synthesizing method of polyester resins includes providing the titanium catalyst, performing a feeding step, performing a heating and pressurizing step and performing a heating and vacuuming step. The titanium catalyst and a heat stabilizer are added into an autoclave before the feeding step or before the heating and vacuuming step.

Provided is an aliphatic polyester composition. The aliphatic polyester composition comprises a polybutylene succinate, wherein the proton nuclear magnetic resonance of the aliphatic polyester composition has a first characteristic peak and a second characteristic peak. The first characteristic peak is located between 3.84 ppm and 4.32 ppm, and the second characteristic peak is located between 5.65 ppm and 5.85 ppm. The integral value of the first characteristic peak is set to be 100 and the integral value of the second characteristic peak is less than 0.10. By controlling the integral value of the second characteristic peak in H.sup.1-NMR of the aliphatic polyester composition, the aliphatic polyester composition has good appearance and low concentration of carboxylic acid end group and thereby the product value thereof is increased.

The present invention relates to a method for preparing a stereoblock polylactide, comprising: a step of obtaining a first reaction mixture with a monomer conversion rate of 80 to 95% by adding a catalyst to a D-lactide and growing a PDLA chain; a step of obtaining a second reaction mixture with a monomer conversion rate of 80 to 95% by adding an L-lactide to the first reaction mixture and growing a racemic PDLLA chain at the end of the PDLA chain; and a step of further adding an L-lactide to the second reaction mixture and growing a PLLA chain at the end of the PDLLA chain through a polymerization reaction. The preparation method is capable of providing a more convenient synthesis by skipping a process of removing residual monomers in the middle of the reaction, and also of preventing multi-blocking and oligomerization of polymer chains due to a mixture of chains by gradually adding polymerizable monomers while controlling the monomer conversion rate in a one-port synthesis, thereby reducing chain transfer during the polymerization.

The present invention relates to a method for preparing a stereoblock polylactide, comprising: a step of obtaining a first reaction mixture with a monomer conversion rate of 80 to 95% by adding a catalyst to a D-lactide and growing a PDLA chain; a step of obtaining a second reaction mixture with a monomer conversion rate of 80 to 95% by adding an L-lactide to the first reaction mixture and growing a racemic PDLLA chain at the end of the PDLA chain; and a step of further adding an L-lactide to the second reaction mixture and growing a PLLA chain at the end of the PDLLA chain through a polymerization reaction. The preparation method is capable of providing a more convenient synthesis by skipping a process of removing residual monomers in the middle of the reaction, and also of preventing multi-blocking and oligomerization of polymer chains due to a mixture of chains by gradually adding polymerizable monomers while controlling the monomer conversion rate in a one-port synthesis, thereby reducing chain transfer during the polymerization.