Abstract: The present invention provides a heat sensitive recording material comprising a recording layer formed on a substrate and containing a colorless or light-colored basic dye and a color acceptor, the material being characterized in that the basic dye is 3-(N-ethyl-N-p-tolyl)amino-6-methyl-7-p-toluidinofluoran, the color acceptor is bis(3-allyl-4-hydroxyphenyl)sulfone and/or 4-hydroxy-4'-isopropoxydiphenylsulfone.

Abstract: The present invention provides a heat sensitive recording material comprising a recording layer formed on a substrate and containing a colorless or light-colored basic dye and a color acceptor, the material being characterized in that the basic dye is 3-diethylamino-7-[m-(trifluoromethyl)phenylamino]fluoran and/or 3-di-n-pentylamino-6-methyl-7-phenylaminofluoran, the color acceptor being 4,4'-dihydroxydiphenylsulfone.

Abstract: The present invention provides a heat sensitive recording material, including a substrate and a heat sensitive recording layer thereon incorporating a colorless or light-colored basic dye and a color acceptor reactive with the dye to form a color when contacted therewith, the recording material also including 1-(4-methoxyphenoxy)-2-(2-methylphenoxy)ethane in the heat sensitive recording layer.

Abstract: In a multi-color heat sensitive recording material comprising a substrate and two or more heat sensitive color-forming layers thereon capable of forming different colors from each other, at least one of the heat sensitive color-forming layers containing a leuco dye and an acidic substance, the recording material characterized in that at least one piperidine derivative represented by the formula [I] ##STR1## wherein R.sub.1 is C.sub.1.about.30 aliphatic group residue which may have C.sub.2.about.20 alkoxycarbonyl group, or C.sub.1.about.30 aliphatic group residue which has ether linkage and oxycarbonyl group; R.sub.2, R.sub.3, R.sub.4, R.sub.5 and X are each methyl group or hydrogen atom; and l is an integer of 1 to 6, is incorporated at the position where a decolorizing function can be effected against the color-forming system comprising a leuco dye and an acidic substance.

Abstract: A new phthalide derivative useful as a colorless chromogenic material has the general formula: ##STR1## wherein R.sub.1 to R.sub.10, X.sub.1, X.sub.2, Y.sub.1, Y.sub.2, Z, a and b have the same meaning as defined hereinbefore.

Abstract: A new phthalide derivative useful as a colorless chromogenic material has the general formula: ##STR1## wherein R.sub.1 to R.sub.10, X.sub.1, X.sub.2, Y.sub.1, Y.sub.2, Z, a and b have the same meaning as defined hereinbefore.

Abstract: This invention provides a multicolor record material comprising a plurality of color forming systems each containing a color forming material and a color developing material and adapted to produce different colors individually, the multicolor record material being characterized in that each of the systems contains a substance which absorbs an infrared beam of specified wavelength for causing the system to produce its color but which substantially does not absorb an infrared beam of different wavelength for causing another system to produce the color thereof.

Abstract: A heat-sensitive record material for use with an infrared laser containing(a) a color forming material,(b) a color developing material, and(c) a light absorbing material selected from the group consisting of (1) natural or synthetic silicate compounds, and (2) baked products obtained by baking a zinc compound and a clay mineral at a temperature of at least 500.degree. C.

Abstract: This invention concerns with an improved microcapsule dispersion prepared by adding the following components to a known microcapsule dispersion containing PVA; a pulp having a specific weighted average fiber length, another type of pulp, carboxymethyl cellulose and/or a specified periodic acid type compound, and is characterized by overcoming the drawbacks of known microcapsule dispersions attended by use of PVA.

Abstract: The residual formaldehyde existing in the aqueous dispersion of microcapsules each having a capsule wall of an aldehyde polycondensation resin formed by polycondensation of formaldehyde with an amine in the presence of an acid catalyst is removed by adjusting the aqueous dispersion to an alkaline state, adding to the aqueous dispersion at least one reaction catalyst which is a member selected from the group consisting of metal hydroxides, phosphates, calcium salts and magnesium salts, and then heating and agitating the aqueous dispersion to cause a reaction to remove residual formaldehyde therefrom.

Abstract: The method of making oil-containing microcapsules comprises the step of (1) preparing an aqueous system comprising an aqueous solution of gelatin and at least one anionic colloid material and oil droplets dispersed in said solution (2) causing coacervation in said aqueous system at a temperature above the gelation point of said gelatin to form a coacervate suspension in which each of said oil droplets is surrounded by a coacervate and (3) cooling said coacervate suspension to a temperature below the gelation points of said gelatin to form multi-nucleus capsules. During the step of cooling the coacervate suspension, aggregation of particles of oil droplets each having a coacervate therearound is controlled by an agitation flow so as to allow formation of multi-nucleus microcapsules having an average diameter within the range of 3 to 20 microns. The gelatin has an average viscosity not larger than 35 millipoise in terms of the value measured by the bloom type pipette method at 40.degree..+-.0.5.degree. C.