Toyobo Co., Ltd.

Asahi Kasei Kabushiki Kaisha

Amane Hirose

Mitsuo Tojo

Makoto Handa

Tatsuya Ogawa

Hiroyuki Honma

Shigeyuki Watanabe

Nobuyuki Nakanishi

Dai Nakagawa

Junichi Togasaki

Provided is a glass fabric formed by weaving warp and weft glass yarns comprising a plurality of glass filaments, wherein the surface of the glass fabric is subjected to surface treatment with a surface treatment agent, and the difference between the dielectric loss tangent and the bulk dielectric loss tangent of the glass fabric as measured by using a split cylinder resonator is greater than 0 and not more than 1.0×10at 10 GHz.

Glass fabric, prepreg, and printed circuit board

Provided is a glass cloth obtained by weaving a glass thread, which is made from a plurality of glass filaments, as a warp and weft. The average filament diameter of the glass filaments is 3.0-4.5 μm. The respective weaving densities of the warp and the weft constituting the glass cloth are, independently, 70-130 threads/25 mm. The standard deviation of weft width of the glass cloth is not more than 30 μm. The weft covering ratio R, which is represented by the expression R=Y/(25400/D) (where R is the weft covering ratio, Y is the average weft width, and D is the weft weaving density) satisfies the relational expression 0.50≤R≤0.83.

Glass cloth, prepreg, and printed wiring board

An object of the present invention is to more conveniently provide a copolyester for a polyester film which exhibits excellent dimensional stability and in particular excellent dimensional stability against environmental changes in, for example, temperature and humidity, and has a small film elongation percentage at 110&#xb0; C. A copolyester of the present invention comprises: (A) an aromatic dicarboxylic acid component; (B) an alkylene glycol component; and (C1) a dimer acid component and/or (C2) a dimer diol component, wherein the copolyester contains, with reference to a molar number of a total dicarboxylic acid component, 0.5 to 3.5 mol % of the dimer acid component (C1) and/or 0.3 to 5.0 mol % of the dimer diol component (C2).

Polyester composition, polyester film, and magnetic recording medium

The invention provides a polyester composition in which the primary repeating units contain an aromatic dicarboxylic acid component (Component A) and an ethylene glycol component (Component C) and a long-chain alkyl dicarboxylic acid component having not less than 6 carbons (Component B) or a long-chain alkyl diol component having not less than 6 carbons (Component D), wherein a sum (WB+WD) of a relative amount (WB) of Component B as calculated based on a total number of moles of Component A and Component B plus a relative amount (WD) of Component D as calculated based on a total number of moles of Component C and Component D are within a range of 2-13 mol %. The invention also provides a polyester film prepared from the polyester composition and having excellent dimensional stability, as well as a magnetic recording medium utilizing the polyester film.

A multi-layer, layered film includes a multi-layer, alternately layered body containing birefringent first layers including a first resin and isotropic second layers including a second resin, in which the multi-layer, layered film has a layer thickness profile with which light at a wavelength of from 380 to 780 nm can be reflected due to optical interference between each of the first layers and each of the second layers, in which a layer thickness profile for an optical thickness of the first layers has a first monotonically increasing region which meets specific requirements, and in which a layer thickness profile for an optical thickness of the second layers has a second monotonically increasing region which meets specific requirements.

Multi-layer layered film

The invention provides a multilayer laminated film containing a multilayer laminated structure of alternately laminated first and second layers, and a thick film layer in contact therewith. The multilayer laminated structure has a layer thickness profile in terms of the physical thickness of repeating first and second layers. The layer thickness profile has a monotonously increasing thickness region and a thin layer region, which has at least three repeating units, a L2/L1 ratio of 0.85 or less, and a A2/L1 ratio of 0.70 or less, where L1 is the maximum repeating unit thickness in the monotonously increasing thickness region, L2 is the maximum repeating unit thickness in the thin layer region, and A2 is the average repeating unit thickness in the thin layer region. The thin layer region is on the thicker side of the monotonously increasing thickness region and in contact with the thick film layer.

Multilayer film stack

To provide a resin film, of which dimensional stability required of an ultra-high density recording medium can be controlled easily by drive tension, and which has processability at high temperature in a processing step of the resin film into a magnetic recording medium. A resin film having a Young's modulus in the film longitudinal direction of 1 GPa or more and a film thickness of 1 &#x3bc;m or more, wherein the product of the Young's modulus in the longitudinal direction and the thickness is 5 GPa&#xb7;&#x3bc;m or more and 20 GPa&#xb7;&#x3bc;m or less and wherein a dimensional change in the film longitudinal direction is &#x2212;2% or more and +2% or less when the film is heated at a rate of 5&#xb0; C./min under a load of 2 kg/mmapplied in the longitudinal direction and the temperature has reached 110&#xb0; C., the resin film satisfying at least either of the following (1) or (2): (1) the Young's modulus in the film longitudinal direction is 6 GPa or less and the film thickness is 4.5 &#x3bc;m or less; and (2) the Young's modulus in the film longitudinal direction is 4 GPa or less and the film thickness is 6 &#x3bc;m or less.

Growing community of inventors

Tokyo, Japan

Amane Hirose