Teijin Limited

Victor Company of Japan, Limited

Tetsuya Hasegawa

Koji Kubo

Tetsuo Yoshida

Hirofumi Murooka

Hiroshi Nakajima

Masahiko Kosuge

Manabu Kimura

Takafumi Niwa

The invented film comprises a layer A composed of a copolyester A, a layer B composed of a copolyester B, and a layer C composed of copolyester C. Layer A is laminated to one side of the layer B. Layer C is laminated to the other side of Layer B. Copolyester A contains 0-15 wt % of rutile titanium oxide (average particle diameter 0.1-0.5 &mgr;m). Copolyester B contains 10-50 wt % of the rutile titanium oxide. Copolyester C contains 0-15 wt % of the rutile titanium oxide. Each of Copolyester A, B, and C has a melting point of 210-245&deg; C. The intrinsic viscosity (&eegr; ) of the polymer part of copolyester A, the intrinsic viscosity (&eegr; ) of the polymer part of copolyester B, and the intrinsic viscosity (&eegr; ) of the polymer part of copolyester C satisfy the following relationship. 0.46&lE;&eegr; &lE;0.66, &verbar;&eegr; -&eegr; &verbar;<0.15, &verbar;&eegr; -&eegr; &verbar;<0.15, and &verbar;&eegr; -&eegr; &verbar;<0.15. The ratio of the apparent density (&rgr;) to the calculated density (&rgr; ) of the entire laminated film satisfies the following formula, 0.75&lE;&rgr;/&rgr; &lE;1.00. The calculated density (&rgr; ) is calculated with density of the polymer part of each copolyester, density of rutile titanium oxide, thickness of each layer, concentration of rutile titanium oxide in each copolyester, and number of copolyester layers.

White laminated polyester film for metallic plate lamination work

Polyester film for metal lamination and the use thereof

Improved disc metal mold provides an improved disc without a ring groove thereon. The improved disc metal mold has a fixed metal mold section and a movable metal mold section for forming a cavity therebetween. One of the fixed and movable metal molds has a stamper having an information signal surface on which an information signal is formed in a form of pits, wherein a fused resin is injected into the cavity to form a disc substrate having a center through hole at the center thereof. The disc metal mold includes the stamper having an center hole at a center thereof for retaining the stamper itself and a retainer for retaining the stamper to engage with the center hole of the stamper. The retainer has a slightly larger diameter at a top surface thereof than a diameter of the center hole of the stamper so that the top surface of the retainer is approximately flush with the information signal surface of the stamper by causing the top end thereof to engage with the center hole of the stamper. Thus, it is possible to provide a recorded disc having a seamless flush information surface without ring groove.

Disc metal mold and recorded disc

Growing community of inventors

Sagamihara, Japan

Tetsuya Hasegawa