Mitsubishi Chemical Corporation

Mitsubishi Chemical Industries Limited

Isamu Fukushima

Masayuki Otake

Makoto Arimura

Hiroshi Masuda

A disc cartridge for a disc-shaped recording medium includes a cartridge body having an opening portion for exposing a portion of a surface of the disc-shaped recording medium contained therein and a shutter for covering and uncovering the opening portion. A slider provided for supporting the shutter, is disposed on the cartridge body and is capable of sliding and is resiliently restored by a spring. The slider is engaged slidably with a groove or protrusion formed along a slide of the cartridge body by way of an engagement part. A portion of an engaging structure between the engagement part of the slider and the cartridge body makes a line contact between a protrusion or protrusion of the engagement part of the slider and the groove or protrusion of the cartridge body.

Disc cartridge with wedge-shaped inclined shutter slider engaging

A method for producing a lactam having the formula: ##STR1## wherein R.sup.1 is a hydrogen atom, or a straight chain or branched chain alkyl group having from 1 to 5 carbon atoms, and R.sup.2 is an organic group having at least 2 carbon atoms, and connected at both ends to the cyclic acid imide group, which comprises reducing a cyclic acid imide having the formula: ##STR2## wherein R.sup.1 and R.sup.2 are as defined above, or its precursor, with hydrogen by means of a cobalt-based catalyst comprising (a) cobalt and (b) at least one modifier component selected from the group consisting of molybdenum, tungsten and rhenium.

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Kurashiki, Japan

Isamu Fukushima