Abstract: An aromatic polyamide film for a high-density magnetic recording medium which has excellent electromagnetic conversion characteristics and few drop outs even when it is used as a base film for a deposited metal thin film magnetic recording medium and enables the production of a large-capacity magnetic recording medium. An aromatic polyamide film for a high-density magnetic recording medium which has surface flatness and excellent transferability, is thereby useful as a base film especially for a high-density magnetic recording medium and can satisfy contradictory requirements, that is, the prevention of a trouble such as projection of protrusions in a calendering step and winding easiness at the same time.

Abstract: A biaxially oriented film made from a wholly aromatic polyamide produced by an acid chloride process, which contains at least one member of inorganic particles having an average particle diameter of 5 to 2,000 nm and selected from the group consisting of hydroxides, carbonates and bicarbonates of metals of groups Ia and IIa of the periodic table. The inorganic particles is derived from inorganic particles which are added as a neutralizing agent to a reaction system to neutralize hydrogen chloride by-produced by the acid chloride reaction and its content corresponds to an excess portion added to the reaction system over the amount required for neutralizing the hydrogen chloride stoichiometrically. The film is useful as a base film for a magnetic recording medium, such as a coated, a multi-layer coated, or a thin metal film high-density magnetic recording medium.

Abstract: A laminated polyester film for use as a film to be laminated on a metal plate, which comprises (A) a first layer formed of (a1) a first aromatic copolyester prepared in the presence of a germanium compound as a polymerization catalyst, which contains terephthalic acid as the main dicarboxylic acid component and ethylene glycol as the main glycol component and which has a melting point in the range of from 210.degree. to 245.degree. C. and a glass transition temperature of at least 60.degree. C., the first layer having (a2) a surface roughness (Ra) in the range of from 2 to 13 nm, and (B) a second layer formed of (b1) a polyester composition obtained by melt-mixing 90 to 45% by weight of a second aromatic copolyester which is composed, as a main recurring unit, of ethylene terephthalate, is produced in the presence of a germanium compound as a polymerization catalyst and has a melting point in the range of from 210.degree. to 252.degree. C.

Abstract: A laminated polyester film comprising an aromatic copolyester layer having a surface roughness of 2 to 13 nm and a polyester layer having a surface roughness (Ra) of at least 15 nm. This laminated polyester film has improved impact resistance particularly at low temperatures and improved taste-retaining property while retaining the excellent moldability, heat resistance, retort sterilization resistance and flavor-retaining property possessed by copolyester films.

Abstract: A biaxially oriented film to be laminated on a metal, which is a laminate film comprising (A) a first layer of a polyester comprising ethylene terephthalate as a main recurring unit; and (B) a second layer formed from a composition of a polycarbonate and polyesters, the polycarbonate and the polyesters being each contained in amounts of 20 to 50% by weight and 50 to 80% by weight based on the total thereof; the polyesters consisting essentially of a first polyester comprising ethylene terephthalate as a main recurring unit and having a terminal carboxyl group concentration of more than 5 eq./10.sup.6 g and a second polyester comprising butylene terephthalate as a main recurring unit and having a terminal carboxyl group concentration of less than 20 eq./10.sup.6 g; and the first and second polyesters being each contained in an amount of 10 to 90% by weight based on the total thereof; and in which (C) the plane orientation coefficients of the first layer and second layer are both in the range of 0.05 to 0.10.

Abstract: A biaxially oriented polyester film made of a polyester composition,(A) which polyester composition comprises (a) an aromatic copolyester having a melting point of 210-245.degree. C., (b) first inert fine solid particles having an average particle diameter of 0.05 to 0.6 .mu.m, and (c) second inert fine solid particles having an average particle diameter of 0.3 to 2.5 .mu.m, the ratio of the average particle diameter of the second inert fine solid particles to the average particle diameter of the first inert fine solid particles being at least 2.5, and the amounts of the components (b) and (c) being 0.01 to 3% by weight and 0.001 to 0.2% by weight, respectively, based on the total weight of the components (a), (b) and (c);(B) which polyester film has a plane orientation coefficient of 0.08 to 0.16; and,(C) which polyester film shows excellent moldability when laminated onto a metal sheet and subjected to deep drawing.A can for drinks, foods, etc.

Abstract: A biaxially oriented laminated polyester film comprising (A) a first layer formed from a first copolyester which is composed of ethylene terephthalate unit as a main recurring unit, and (B) a second layer formed from a polyester composition containing (B1) a second copolyester which is composed of ethylene terephthalate unit as a main recurring unit and (B2) a third (co)polyester which is composed of butylene terephthalate unit as a main recurring unit and is contained in an amount of 1 to 40% by weight or (B3) a filler having an average particle diameter of 2.5 .mu.m or less and is contained in an amount of 5 to 80% by weight in place of the third (co)polyester (B3), the second layer being to constitute a surface to be bonded onto a metal surface when the laminated film is laminated on the metal sheet. This composition can give metal cans, e.g.

Abstract: A biaxially oriented polyester film comprising a copolyester which contains a lubricant having an average particle diameter of no greater than 2.5 .mu.m and has a melting point of from 210.degree. to 245.degree. C., the film having a plane orientation coefficient of from 0.10 to 0.16, a thermal shrinkage at 150.degree. C. of no higher than 10%, and a density of lower than 1.385 g/cm.sup.3, and optionally a refractive index in a direction of thickness of from 1.495 to 1.530 as well as a film plane refractive index of from 1.61 to 1.66 in all directions.

Abstract: The present invention provides a polyester film for processing of a metal sheet, which shows excellent molding-processability when it is laminated onto a metal sheet and the laminated metal sheet is made into a can by deep drawing or the like and which is suitable and useful for production of a metal can having excellent heat resistance, impact resistance and flavor-retaining property.A polyester film used for lamination onto a metal sheet for processing of said metal sheet, characterized in that the film is formed from 99 to 60% by weight of a copolyester, as the component A, having an ethylene terephthalate unit as the main recurring unit and having a melting point of 210 to 245.degree. C. and 1 to 40% by weight of a polybutylene terephthalate or a copolyester, as the component B, having a butylene terephthalate unit as the main recurring unit and having a melting point of 180 to 223.degree. C., and further comprising a lubricant having an average particle diameter of 2.5 .mu.

Abstract: A polyester film for metal sheet lamination processing which comprises a co-polyester containing a lubricant having an average particle diameter of 2.5 .mu.m or less and the co-polyester having a melting point of 210.degree. to 245.degree. C.; and wherein the refractive index in the direction of film thickness is 1.505 to 1.550, the refractive index in the direction of the film plane is 1.61 to 1.66 about all directions, subpeak by DSC is 150.degree. to 205.degree. C., and optionally, protrusions on the film surface satisfy the formula0.1.ltoreq.Nd/N.ltoreq.0.5wherein N is the number of all the protrusions on the film surface and Nd is the number of the protrusions each containing the lubricant as its nucleus and having a sunk hollow around it.

Abstract: A biaxially oriented polyester film comprising a copolyester which contains a lubricant having an average particle diameter of no greater than 2.5 .mu.m and has a melting point of from 210.degree. to 245.degree. C., the film having a plane orientation coefficient of from 0.10 to 0.16, a thermal shrinkage at 150.degree. C. of no higher than 10%, and a density of lower than 1.385 g/cm.sup.3, and optionally a refractive index in a direction of thickness of from 1.495 to 1.530 as well as a film plane refractive index of from 1.61 to 1.66 in all directions.

Abstract: A biaxially oriented polyester film composed of an intimate mixture of an aromatic polyester, barium sulfate particles having an average particle diameter of 0.1 to 10 micrometers, and an alkali metal or alkaline earth metal salt of a higher fatty acid having 8 to 34 carbon atoms. The fatty acid metal salt has a melting point in the range of 120.degree. to 320.degree. C. The biaxially oriented polyester film has substantially no difference in surface properties such as roughness and the degree of gloss between its surface and back, and can be produced industrially advantageously with high producibility and excellent operability.

Abstract: A process for thermoremanent duplication of a magnetic recording tape, which comprises recording magnetic signals by thermoremanent duplication on a slave tape consisting of a polyester film base and a layer of a ferromagnetic material coated thereon, and then heat-treating said magnetic recording slave tape without stretch at a temperature of at least 40.degree.C. but less than the Curie point of said ferromagnetic material. Dimensional changes of the slave tape after thermal duplication are thereby reduced.

Abstract: A biaxially oriented polyethylene-2,6-naphthalate film, which comprises a blended mixture of1. a polyethylene-2,6-naphthalate resin which may contain a unit derived from not more than 10mol% of a polyester-forming component other than a polyethylene-2,6-naphthalate-forming component, and2. 0.5 to 10% by weight, based on the polyethylene-2,6-naphthalate resin (1), of a polyester resin other than the polyethylene-2,6-naphthalate resin (1) in which the amount of the homopolyester unit is at least 90 mol%,Said film having a softing point at least 1.degree.C. higher than the its equilibrium softening point, and a process for its production.