Mitsui Toatsu Chemicals, Incorporated

Hiroshi Aiga

Keisuke Takuma

Kimitoshi Kato

Tsutomu Nishizawa

Yasuyuki Yamada

Tsukasa Ohyama

Tamio Mikoda

Ken Mukai

Shizuo Kuroda

Fumio Fujii

Tetsuo Watanabe

Tunehiro Sakai

Tsukasa Oyama

Sizuo Kuroda

High-purity 1,4,5,8-tetraanilidoanthraquinones which are substituted at the p-position of at least one of four anilido benzene rings by a halogen atom are good near infrared rays absorbing filters and at prepared from high purity 1,4,5,8-tetrachloroanthraquinone by reaction with a correspondingly substituted aniline or mixture of anilines in the presence of a salt of an aliphatic carboxylic acid,. a benzyl alcohol derivative and copper ions as reaction catalyst.

Halogenated anthraquinone and their use as near infrared rays absorbing

Dichroic coloring agents which have a blue to blue-violet hue and have not been used to date for liquid crystal displays are disclosed. These coloring agents are represented by the following formula: ##STR1## wherein X is S or NH; R.sub.1 is a hydrogen atom, halogen atom, alkyl group or alkoxy group; and R.sub.2 is a hydrogen atom, alkyl group, aryl group or aralkyl group.

Dichroic coloring agents for liquid crystal displays

Dichroic azo dyestuffs and liquid crystal composition containing said

A process for producing dianthraquinone-N,N'-dihydrazine or its chlorination product, which comprises condensing 1-aminoanthraquinone at an elevated temperature in the presence of 1,3-dimethyl-2-imidazolidinone using an oxidizing agent and an alkaline condensing agent, and subjecting the resulting condensation product to a treatment known per se.

Process for producing dianthraquinone-N,N'-dihydrazine and its

Mixtures of water-insoluble monoazo dyestuffs are disclosed together with the dyeing, padding or printing of polyester material therewith. The water-insoluble monoazo dyestuffs of the following general formula (A) ##SPC1## in which Y represents hydrogen, chlorine, bromine, methyl, ethyl, methoxy, ethoxy or cyano; R.sub.1 represents methoxy, ethoxy or phenoxy; R.sub.2 represents methyl or ethyl; R.sub.3 represents hydrogen, methyl, ethyl, cyanoethyl or allyl; and R.sub.4 represents methyl, ethyl, propyl, butyl, allyl or phenyl, are suitable for the production of inexpensive navy shades of good fastness to light, washing, perspiration, sublimation and heat setting; however, difficulties sometimes arise in the case of these dyestuffs. The improvement disclosed comprises overcoming said difficulties and providing new navy shades by using a mixture of at least two dyestuffs, in one of which the Y constituent above is hydrogen and in the other of which the Y constituent is replaced by constituent X which represents chlorine, bromine, methyl, ethyl, methoxy, ethoxy or cyano.

Dyestuff mixtures and process for dyeing polyester fiber therewith

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Ohmuta, Japan

Hiroshi Aiga