Abstract: A biaxially oriented laminated polyester film which has excellent dimensional stability to environmental changes such as temperature and humidity variations and excellent flatness and windability. A biaxially oriented laminated polyester film comprising a film layer B on one side of a film layer A and having a surface roughness (RaB) on the film layer B side which is 1.0 nm or more larger than the surface roughness (RaA) on the film layer A side, wherein at least one of the film layers comprises an aromatic polyester (I) composed of a glycol component and a dicarboxylic acid component containing 5 mol % or more and less than 80 mol % of a recurring unit represented by the following formula (A): wherein RA is an alkylene group having 1 to 10 carbon atoms.

Abstract: An object of the present invention is to provide a polyester film having excellent dimensional stability to temperature and humidity. The present invention is a polyester containing a dicarboxylic acid component and a diol component, wherein (i) the dicarboxylic acid component contains not less than 5 mol % and less than 50 mol % of a recurring unit represented by the following formula (A) and more than 50 mol % and not more than 95 mol % of a recurring unit represented by the following formula (B): wherein RA is an alkylene group having 2 to 10 carbon atoms, wherein RB is a phenylene group or naphthalenediyl group; and (ii) the diol component contains 90 to 100 mol % of a recurring unit represented by the following formula (C): —O—RC—O—??(C) wherein RC is an alkylene group having 2 to 10 carbon atoms, and a film comprising the same.

Abstract: To provide an aromatic polyester which is formed into a film having excellent heat resistance, color, mechanical properties, dimensional stability and gas barrier properties and a manufacturing process thereof; the aromatic polyester comprises a dicabroxylic acid component and a diol component, wherein (i) the dicarboxylic acid component contains 50 to 100 mol % of a recurring unit represented by the following formula (A): ?wherein R is an alkylene group having 2 to 10 carbon atoms, (ii) the aromatic polyester has an intrinsic viscosity measured at 35° C. by using a mixed solvent of P-chlorophenol and 1,1,2,2-tetrachloroethane (weight ratio of 40/60) of 0.4 to 3.0; (iii) the aromatic polyester has a content of a recurring unit represented by the following formula (D) of less than 10 mol %: —O—CH2CH2—O—CH2CH2—O—??(D) (iv) the aromatic polyester has a terminal carboxyl group concentration of 200 eq/ton or less; and (v) the aromatic polyester has an alkali metal content of 300 ppm or less.

Abstract: It is an object of the present invention to provide a biaxially oriented laminated polyester film which has excellent dimensional stability to environmental changes such as temperature and humidity variations and excellent flatness and windability. The present invention is a biaxially oriented laminated polyester film comprising a film layer B on one side of a film layer A and having a surface roughness (RaB) on the film layer B side which is 1.0 nm or more larger than the surface roughness (RaA) on the film layer A side, wherein at least one of the film layers comprises an aromatic polyester (I) composed of a glycol component and a dicarboxylic acid component containing 5 mol % or more and less than 80 mol % of a recurring unit represented by the following formula (A): wherein RA is an alkylene group having 1 to 10 carbon atoms.

Abstract: An object of the present invention is to provide a polyester film having excellent dimensional stability to temperature and humidity. The present invention is a polyester containing a dicarboxylic acid component and a diol component, wherein (i) the dicarboxylic acid component contains not less than 5 mol % and less than 50 mol % of a recurring unit represented by the following formula (A) and more than 50 mol % and not more than 95 mol of a recurring unit represented by the following formula (B): wherein RA is an alkylene group having 2 to 10 carbon atoms, wherein RB is a phenylene group or naphthalenediyl group; and (ii) the diol component contains 90 to 100 mol % of a recurring unit represented by the following formula (C): —O—RC—O—??(C) wherein RC is an alkylene group having 2 to 10 carbon atoms, and a film comprising the same.

Abstract: To provide an aromatic polyester which is formed into a film having excellent heat resistance, color, mechanical properties, dimensional stability and gas barrier properties and a manufacturing process thereof; the aromatic polyester comprises a dicarboxylic acid component and a diol component, wherein (i) the dicarboxylic acid component contains 50 to 100 mol % of a recurring unit represented by the following formula (A): wherein R is an alkylene group having 2 to 10 carbon atoms, (ii) the aromatic polyester has an intrinsic viscosity measured at 35° C. by using a mixed solvent of P-chlorophenol and 1,1,2,2-tetrachloroethane (weight ratio of 40/60) of 0.4 to 3.0; (iii) the aromatic polyester has a content of a recurring unit represented by the following formula (D) of less than 10 mol %: —O—CH2CH2—O—CH2CH2—O—??(D) (iv) the aromatic polyester has a terminal carboxyl group concentration of 200 eq/ton or less; and (v) the aromatic polyester has an alkali metal content of 300 ppm or less.

Abstract: A polyester having a good color tone (a high L value and a low b value) and a low acetaldehyde content is obtained by using a catalyst containing a reaction product of (A) a titanium compound (1) represented by the general formula (I) and/or a titanium compound (2) obtained by reacting the titanium compound (1) of the general formula (I) with an aromatic polyhydric carboxylic acid represented by the general formula (II) or an anhydride thereof, with (B) a phosphorus compound (3) represented by the general formula (III). [wherein R1, R2, R3, R4 and R5=a C2-C10 alkyl group, k=1 to 3, m=2 to 4, and R6=a substituted or non-substituted C6-C20 aryl group or a C6-C20 alkyl group].

Abstract: A poly(ethylene aromatic dicarboxylate ester) resin usable for the production of fibers, films and bottle-formed articles, is produced by polycondensing a diester of an aromatic dicarboxylic acid with ethylene glycol by using a catalyst including a non-reacted mixture or reaction product of a titanium compound component including at least one member selected from titanium alkoxides and reaction products of the titanium alkoxides with aromatic polyvalent carboxylic acids or anhydrides thereof, with a specific phosphorus compound, in which catalyst the contents of titanium and phosphorus elements are controlled.

Abstract: A poly(ethylene aromatic dicarboxylate ester) resin usable for the production of fibers, films and bottle-formed articles, is produced by polycondensing a diester of an aromatic dicarboxylic acid with ethylene glycol by using a catalyst including a non-reacted mixture or reaction product of a titanium compound component including at least one member selected from titanium alkoxides and reaction products of the titanium alkoxides with aromatic polyvalent carboxylic acids or anhydrides thereof, with a specific phosphorus compound, in which catalyst the contents of titanium and phosphorus elements are controlled.

Abstract: A polyester having a good color tone (a high L value and a low b value) and a low acetaldehyde content is obtained by using a catalyst containing a reaction product of (A) a titanium compound (1) represented by the general formula (I) and/or a titanium compound (2) obtained by reacting the titanium compound (1) of the general formula (I) with an aromatic polyhydric carboxylic acid represented by the general formula (II) or an anhydride thereof, with (B) a phosphorus compound (3) represented by the general formula (III).

Abstract: The present invention provides a biaxially oriented polyester film made of a polyester containing 0.01 to 5% by weight of crosslinked polymer particles characterized by:(1) having a particle size distribution ratio (.gamma.) of 1.3 to 3.5,(2) having an average particle diameter of 0.1 to 2 .mu.m,(3) having a non-circularity of 3.4 or more, and(4) having a standard deviation of noncircularity, of at least 0.16.The polyester film of the present invention has a flat surface having a small number of large protuberances, excellent running property and excellent winding property, and can be produced economically. The film has excellent properties for use as a base for various magnetic recording media.