Sanko Kaihatsu Kagaku Kenkyusho

Kanzaki Paper Manufacturing Co., Ltd.

Sanko Co., Ltd.

Sanko Haihatsu Kagaku Kenkyusho

Eiji Kawabata

Shigeru Oda

Toranosuke Saito

Tomoharu Shiozaki

Takashi Ishibashi

Tetsuo Shiraishi

Masato Tanaka

Yoshito Nakagawa

Toshio Kimura

Hiroshi Sumitomo

Takaaki Mori

Shouichi Murata

Tjang Kie Tan

The invention provides a heat-sensitive recording material, which is highly sensitive, is almost free of staining on the background, and gives a recorded image excellent in stability during storage, by using a finely divided sensitizer dispersion excellent in shelf stability produced in a short time with high volumetric efficiency. The invention relates to a method of producing a sensitizer dispersion, which comprises emulsifying and finely dividing a heat-sensitive recording sensitizer by melting under heating in an aqueous emulsifying dispersant, and then crystallizing the finely divided emulsified dispersion under rapid cooling, wherein the sensitizer is at least one member selected from the group consisting of 1,2-bis(phenoxy)ethane, 1,2-bis(3-methylphenoxy)ethane, 1,2-bis(4-methylphenoxy)ethane, p-benzylbiphenyl, di-p-methylbenzyl oxalate, and &#x3b2;-naphthyl benzyl ether.

Method for producing material containing sensitizer dispersed therein for thermal recording article and a thermal recording article

There is provided a developer composition including at least one of sulfonyl compounds represented by formula (1) and at least one of sulfonyl compounds represented by formula 2: ##STR1## wherein X is H or lower alkyl, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 which may be the same or different, present H, halogen or lower alkyl and Y represents alkyl, benzenesulfonyl, benzoyl et al, A thermalsensitive recording medium having the above developer is of high sensitivity, less surface-blushing with lapse of time and is excellent in storage stability of a recorded image, particularly in heat resistance, humidity resistance and anti-plasticizer.

Sulfonyl compound and thermalsensitive recording medium using the same

A thermal recording medium comprising a as a developer a sulfonyl compound represented by general formula (1) or a polyvalent metal salt thereof. ##STR1## where X represents H or a lower alkyl group, R.sub.1, R.sub.2 and R.sub.3 represent H, halogen atom, a hydroxyl group, a lower alkyl group or a cycloalkyl group, R.sub.4, R.sub.5 and R.sub.6 represent H, halogen atom, a lower alkyl group or a cycloalkyl group, and R.sub.7 represents H or ##STR2## where R.sub.4, R.sub.5 and R.sub.6 are as defined above. The thermal recording medium has a high sensitivity and a lower background blush during storage, and also has excellent stability against heating, moisture and plasticizer.

Sulfonyl compound and thermal-sensitive recording medium using the same

Herein disclosed is a method for preparing a nuclear-substituted salicylic acid or a metal salt thereof represented by the following general formula (1): ##STR1## [wherein R.sub.1 and R.sub.2 each represents a t-butyl group, a t-amyl group, a t-octyl group, an isononyl group or an isododecyl group, provided that at least one of R.sub.1 and R.sub.2 represents an isononyl group or an isododecyl group; M represents a hydrogen atom or a metal atom; and n is the atomic valency of the metal atom M] which comprises the step of subjecting, to a Kolbe-Schmitt reaction, an alkali metal salt of a nuclear-substituted phenol represented by the following general formula (2): ##STR2## [wherein R.sub.1 and R.sub.2 are the same as those defined above] in which 100 to 50% of the alkali metal salt is potassium salt and 0 to 50% thereof is sodium salt, in a substantially water-insoluble solvent as a reaction medium. The method makes it possible to improve the yield of the specific nuclear-substituted salicylic acid and metal salts thereof and to provide such products having high purity without any post-treatment. The compounds can be used in color developers for pressure-sensitive recording sheets without any additional purification treatment.

Color developer for pressure-sensitive recording sheets

An aqueous dispersion of a developer for pressure-sensitive recording sheet, having superior handling performance and storage stability in a high concentration and a process for producing the dispersion are provided, which developer is expressed by the formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 may be the same or different and represent H, halogen, alkyl of 1 to 9 carbon atoms, alkylene, cycloalkyl, cycloalkylene, phenyl, nucleus-substituted phenyl, aralkyl or nucleus-aralkyl; adjacent two of R.sub.1 to R.sub.4 may form a ring; n is an integer of one or more; and M is Mg, Ca, Zn, Al, Fe, Co, Ni or a basic ion of the foregoing, and which developer has a softening point of 30.degree. C. or higher and is dispersed in water, containing a dispersing agent, the size of particles of the developer being 0.3 to 5.mu. in terms of average particle diameter, and the proportion of right spherical particles in the total particles being 50% or more; and which process comprises emulsifying-dispersing the developer in water containing a dispersing agent at a temperature higher by at least 30.degree. C. than the softening point of the developer, follower by cooling, or dissolving the developer in an organic solvent, emulsifying-dispersing the solution in water containing a dispersing agent and distilling off the solvent from the dispersion on heating, or using a polyvinyl alcohol having a polymerization degree of 500 or more and a saponification degree of 70% or more.

Aqueous dispersion of a developer for pressure-sensitive recording sheet

Growing community of inventors

Osaka, Japan

Eiji Kawabata