A terminal modified polybutylene terephthalate resin has a weight average molecular weight Mw of 10,000 to 100,000, a melting point of 210 C. to 235 C., and a melt viscosity at 250 C. of not more than 10 Pa.Math.s, and includes 90 to 300 mol/ton of a compound having a (poly)oxyalkylene structure, the compound being terminally bound in the resin, wherein the weight average molecular weight Mw represents a relative weight average molecular weight with respect to the molecular weight of a standard poly(methyl methacrylate) as determined by gel permeation chromatography using hexafluoroisopropanol (supplemented with 0.005 N sodium trifluoroacetate) as a mobile phase.

Disclosed is a modified endcapped polyalkylene terephthalate such as modified endcapped polybutylene terephthalate, as well as processes for making the modified endcapped polybutylene terephthalate and compositions and articles derived therefrom.

Disclosed is a modified endcapped polyalkylene terephthalate such as modified endcapped polybutylene terephthalate, as well as processes for making the modified endcapped polybutylene terephthalate and compositions and articles derived therefrom.

A thermoplastic polyester resin includes a residue of an aromatic dicarboxylic acid or an ester-forming derivative thereof and a residue of a diol or an ester-forming derivative thereof, as main structural units, wherein the thermoplastic polyester resin has a hydroxy group concentration of 0.050 mmol/g or less. The use of such a thermoplastic polyester resin enables production of a molded article having excellent mechanical properties and heat resistance, and a reduced dielectric loss tangent at a high frequency of 1 GHz or more.

A thermoplastic polyester resin includes a residue of an aromatic dicarboxylic acid or an ester-forming derivative thereof and a residue of a diol or an ester-forming derivative thereof, as main structural units, wherein the thermoplastic polyester resin has a hydroxy group concentration of 0.050 mmol/g or less. The use of such a thermoplastic polyester resin enables production of a molded article having excellent mechanical properties and heat resistance, and a reduced dielectric loss tangent at a high frequency of 1 GHz or more.

The present invention relates to an epoxy resin curing agent having a structure of Formula I and preparation methods and uses thereof. The present invention makes a resin composition formed by the epoxy resin curing agent have good low dielectric properties by using an epoxy resin curing agent having a specific structure, and the cured products of the epoxy resin composition have low dielectric constant and dielectric loss and good heat resistance and are low dielectric materials having great economic properties and being environmental friendly.

A composition with improved adhesive and sealant properties comprises a) a pre-polymer comprising a polymeric unit of the general formula (-A-B-).sub.n, wherein A represents a substituted or un-substituted ester, B represents a substituted or un-substituted acid ester comprising at least two acid ester functionalities, and n represents an integer greater than 1; wherein the content of grafted anhydride in the composition is less than 0.05 mol/mol of polyacid.

A composition with improved adhesive and sealant properties comprises a) a pre-polymer comprising a polymeric unit of the general formula (-A-B-).sub.n, wherein A represents a substituted or un-substituted ester, B represents a substituted or un-substituted acid ester comprising at least two acid ester functionalities, and n represents an integer greater than 1; wherein the content of grafted anhydride in the composition is less than 0.05 mol/mol of polyacid.

The invention relates to a process for the chemical production of a polyester (co)polymer starting from monomers and/or oligomers, comprising reacting a mixture of at least (a) one or more diol monomers, and (b) one or more dicarboxylic acid monomers and/or esters thereof, and/or one or more oligomers comprising monomer units of (a) and (b); wherein at least one diol monomer (a) is a secondary diol monomer; and wherein in the process also is added (c) a monohydric alcohol with a boiling point at ambient pressure of equal to or higher than 175 C. and an acid dissociation constant determined at 25 C. in water of equal to or less than 12.0 and equal to or more than 7.0, in an amount of 2.5-100 weight % with regard to the total weight of monomers and/or oligomers.

The invention relates to a process for the chemical production of a polyester (co)polymer starting from monomers and/or oligomers, comprising reacting a mixture of at least (a) one or more diol monomers, and (b) one or more dicarboxylic acid monomers and/or esters thereof, and/or one or more oligomers comprising monomer units of (a) and (b); wherein at least one diol monomer (a) is a secondary diol monomer; and wherein in the process also is added (c) a monohydric alcohol with a boiling point at ambient pressure of equal to or higher than 175 C. and an acid dissociation constant determined at 25 C. in water of equal to or less than 12.0 and equal to or more than 7.0, in an amount of 2.5-100 weight % with regard to the total weight of monomers and/or oligomers.