Toyo Kohan Co., Ltd.

Toshiyuki Ueda

Shinichi Aoki

Taizo Sato

Naomi Yabuta

Norimasa Maida

Yoshimi Itoh

Masahiro Fukumoto

Jun Agari

A method of producing a stretched film comprising melt-coextruding a thermoplastic resin A and a thermoplastic resin B to produce a composite filmhaving both-end filmsof the thermoplastic resin B arranged in parallel at both end portions of the main filmof the thermoplastic resin A in the direction of width thereof, stretching the composite film, and cutting and removing both end portions of the stretched film in the direction of width, wherein a film stretch stress value of the both-end filmsis larger than a film stretch stress value of the main filmat the same stretching ratio. This minimizes an increase in the thickness at both end portions of the film in stretching the film and decreases the widths by which both end portions of the expensive resin film are to be cut and removed for producing a film.

Method of producing stretched film and stretched film

A material for a shadow mask, characterized in that it has a chemical composition: C=0.0030 wt %, Si=0.03 wt %, Mn: 0.1 to 0.5 wt %, P=0.02 wt %, S=0.02 wt %, Al: 0.01 to 0.07 wt %, N=0.0030 wt %, B: an amount satisfying 0.5&#x2266;B/N&#x2266;2, and balance: Fe and inevitable impurities, and can form a shadow mask having a coercive force Hc of 90 A/m or less; and a method for producing the material, characterized in that use is made of a raw material having the above chemical composition, the finishing temperature in hot rolling is lower than Ar3 point by O to 30&#xb0; C., the coiling temperature is 650 to 700&#xb0; C., and the rolling reduction percentage in the final rolling (secondary cold rolling) is 30 to 45%. The material produced by the method exhibits magnetic characteristics being uniform in a coil and excellent as described above.

Material for shadow mask, method for production thereof, shadow mask comprising the material and picture tube using the shadow mask

A material for shadow mask having the following composition of components: C&#x2266;0.0008 wt %, Si&#x2266;0.03 wt %, Mn:0.1 to 0.5 wt %, P&#x2266;0.02 wt %, S&#x2266;0.02 wt %, Al:0.01 to 0.07 wt %, N&#x2266;0.0030 wt %, B: an amount satisfying the formula: 5 ppm&#x2266;B&#x2212;11/14&#xd7;N&#x2266;30 ppm, balance: Fe and inevitable impurities; a method for producing the material; a shadow mask using the material (cold rolled steel sheet); and an image receiving tube equipped with the shadow mask. The material has excellent etching characteristics, which are uniform within the same coil, and excellent press formability.

Material for shadow mask, method for production thereof, shadow mask and image receiving tube

A subject of the present invention is to provide for a shadow mask material for a color picture tube with excellent tensile strength and excellent high temperature creep strength, a shadow mask made of the shadow mask material and a color picture tube with the shadow mask. Material for a shadow mask is made from low carbon steel containing manganese of equal or more than 0.60 wt % and aluminum of 0.002 to 0.12 wt %. A shadow mask is made of the material and the shadow mask is installed in a picture image tube.

Raw material for shadow mask for color image receiving tube

A material for shadow mask having the following composition of components: C&lE;0.0008 wt %, Si&lE;0.03 wt %, Mn:0.1 to 0.5 wt %, P&lE;0.02 wt %, S&lE;0.02 wt %, Al:0.01 to 0.07 wt %, N&lE;0.0030 wt %, B: an amount satisfying the formula: 5 ppm&lE;B-11/14&times;N&lE;30 ppm, balance: Fe and inevitable impurities; a method for producing the material; a shadow mask using the material (cold rolled steel sheet); and an image receiving tube equipped with the shadow mask. The material has excellent etching characteristics, which are uniform within the same coil, and excellent press formability.

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Yamaguchi-ken, Japan

Toshiyuki Ueda