Diafoil Company, Ltd.

Diafoil Hoechst Company, Limited

Mitsubishi Chemical Industries Limited

Seiji Sakamoto

Chikakazu Kawaguchi

Yoshio Meguro

Masamichi Watanabe

Takashi Harada

Kazuo Endo

Toshifumi Takisawa

Yoshinori Sato

Kunio Bizen

Takuo Nakahara

Akikazu Yano

Yuzo Otani

Jun Takahashi

Narihiro Masuda

Tomoyuki Kotani

Masashi Inagaki

Kenji Kato

Nobuyasu Shudo

Kiyoshi Yasumura

Toshifumi Watanabe

Takahashi Harada

A biaxially orientated polyester film for sublimitation type thermal transfer printing having a coating layer and a sublimation type ink layer formed on the coating layer. The coating layer comprises an aqueous acrylic resin (A), an aqueous polyester (B) and an aqueous epoxy compound (C), weights of which satisfy the relationships: (1) 0.30.ltoreq.W.sub.A .ltoreq.0.90, (2) 0.10.ltoreq.W.sub.B .ltoreq.0.50, (3) 0.05.ltoreq.W.sub.C .ltoreq.0.30, and (4) 0.25.ltoreq.W.sub.C /W.sub.B .ltoreq.2 in which W.sub.A, W.sub.B and W.sub.C are weight ratios of the aqueous acrylic resin (A), the aqueous polyester (B), and the aqueous epoxy compound (C), respectively based the whole weight of the coating layer.

Polyester film for sublimation type thermal transfer printing

A biaxially oriented polyester film for a magnetic recording medium contains: 1) at least two different sizes of synthetic calcium carbonate particles; and 2) aluminum oxide particles to produce a film with excellent surface uniformity, running properties, and slittability wherein the film generates few scratches and low amounts of abrasion dust. The synthetic calcium carbonate particles are surface treated with a polycarboxylic acid, followed by treatment with a phosphorus compound. The biaxially oriented polyester film can comprise a layer in a multilayer film.

Biaxially oriented polyester film for magnetic recording medium

A biaxially oriented polyethylene-2,6-naphthalate (PEN) film for capacitor dielectric which contains the specific monodisperse cross-linked polymer particles is described. The capacitors using the PEN film have excellent handling qualities and workability as well as excellent electrical properties.

Biaxially oriented polyester film for capacitor dielectric

Disclosed herein is a magnetic recording medium comprising: a stretched polyethylene-2,6-naphthalate multilayered film having a high-roughness surface and a low-roughness surface; a coating layer (A) having specific surface properties and being formed on the high-roughness surface of said multilayered film; a coating layer (B) having a specific surface property and being formed on the low-roughness surface of said multilayered film; and a thin ferromagnetic metal film formed on said coating layer (B).

Magnetic recording medium comprising a polyethylene-2,6-naphthalate

A novel biaxially stretched polyester film having excellent transparency and slipperiness is disclosed. The biaxially stretched polyester comprises a polyester composition which exhibits a film haze of not more than 1% after it is made into a film having a thickness of 100 .mu.m and 50-500 ppm on the basis of the weight of monodispersed cross-linked high polymer particles having an average particle diameter of 0.8-1.4 .mu.m and exhibits a deformability of 1.2-5.0 in a biaxially stretched polyester film.

Biaxially stretched polyester film

A biaxially oriented polyester film containing a specific calcium carbonate is described. The calcium carbonate contained in the film is specified by its vaterite form, its average particles size of 0.07 to 1.5 .mu.m, and its particle size distribution ratio of not more than 2.00. The biaxially oriented polyester film containing such specific calcium carbonate is excellent in both the running property and wear resistance, and suitable for the use as a base of magnetic recording media.

Polyester film for magnetic recording media

A biaxially oriented polyester film containing 0.05 to 3 wt % of agglomerates of primary particles of aluminum oxide having an average particle size of 5 to 40 nm, the agglomerates having an average particle size of 50 to 400 nm. The film of the present invention is excellent in the wear resistance against various members such as a metal pin, and suitable for various industrial purposes including a base film of a magnetic recording medium.

Biaxially oriented polyester film

A biaxially oriented polyester film containing 0.01 to 4 wt %, based on the polyester film, of inorganic particles, the volumetric shape parameter being 0.02 to 0.2, the weight-average particle size being 0.05 to 3 .mu.m, and the ratio (Dw/Dn) of the weight-average particle size (Dw) and the number-average particle size (Dn) being not more than 1.1 is disclosed. The film of the present invention has a uniform surface and shows excellent running property and wear resistance so that it is useful as a base film for a magnetic tape, for example. Thus, the film of the present invention has a high industrial value.

Disclosed herein is a polyester composition which comprises a polyester with a terminal carboxyl group content of 40 to 80 equivalents/10.sup.6 and 0.0 to 5 wt %, based on the total amount of the polyester composition, aluminum oxide particles of 0.005 to 5 .mu.m in average particle diameter and which has a melt resistivity of 6 x 10.sup.6 to 5 x 10.sup.8 .OMEGA..cm. By using the polyester composition, it is possible to successively produce a film having excellent wear resistance and flatness over a long production run.

Polyester composition

Disclosed in this invention is a polyester film for magnetic recording media, containing 0.05 to 5% by weight of inactive inorganic particles (A) having a Mohs hardness of 6 or above and an average particle size of 0.005 to 1.0 .mu.m and 0.01 to 2.0% by weight of inactive particles (B) having an average particle size which is greater than that of the particles (A) and in the range of 0.1 to 3.0 .mu.m, the polyester film having an intrinsic viscosity in the range of 0.52 to 0.65. The polyester film of this invention is excellent in abrasion resistance, scuff resistance and slitting qualities and useful as a base film for magnetic recording media.

Disclosed herein is a uniaxially or biaxially oriented polyphenylene sulfide film wherein the number of n-order of interference fringes Hn (per mm.sup.2) as measured by a multiple interference method satisfies the following relations (1) and (2) at the same time:

Polyphenylene sulfide film

A polyester film suitable for use as the magnetic tape base for video recording, capable of high density recording and having stable slidability or running characteristics. The polyester film is made of a polyester which contains 0.05-1 wt % particles containing calcium and phosphorus and of which the number n of the second interference fringes (number/mm.sup.2) and the average centerline roughness (.mu.m) satisfy the following relationships:

Polyester film for magnetic recording tape

There is disclosed a polyester film suitable for use in magnetic tapes having the characteristics represented by the following equations: ##EQU1## wherein N.sub.1 is the number of peaks of surface projections per millimeter;

Polyester films suitable for use in magnetic tapes

Disclosed herein is a biaxially oriented polyethylene naphthalate film having a center line average roughness [Ra(.mu.m)] and a film thickness [T(.mu.m)] which satisfy the following formula: ##EQU1## produced by the electrostatic cooling method from polymethylene naphthalate having a resistivity of 1.times.10.sup.7 to 5.times.10.sup.8 .OMEGA..cm as measured in the molten state.

Polyethylene naphthalate film

Disclosed herein is an electrical insulating material which comprises biaxially oriented polyethylene naphthalate film having a center line average roughness of 0.008 to 0.08 .mu.m as measured on the surface thereof and a resistivity of 5.times.10.sup.7 to 5.times.10.sup.10 .OMEGA..multidot.cm as measured in the molten state.

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Machida, Japan

Seiji Sakamoto