Abstract: A thermosensitive recording material comprising a leuco dye, a color developer and a water-soluble lubricant such as an alkylphosphate compound having formula (I) or (II): ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 each independently are an alkyl group, an alkynyl group or a monovalent metallic element, but they cannot be the metallic element at the same time; or ##STR2## wherein R.sub.4 is an alkyl group or an alkynyl group, and R.sub.5 is a monovalent metallic element.

Abstract: A heat-sensitive recording material having a superior resistance against water, plasticizers, and oily substances, is provided with a heat-sensitive color-forming layer formed on a surface of a substrate sheet and comprising a dye precursor, a color-developing agent, and a binder; and a protecting layer formed on the heat-sensitive color-forming layer and comprising (A) a polyvinylalcohol resin, (B) a water-soluble cross-linking agent, (C) at least one organic boron-containing polymer of the formula (I): ##STR1## and optionally (D) an acetoacetylated polyvinylalcohol resin.

Abstract: This invention relates to a thermosensitive recording material containing at least one of durene derivative represented by the formula (I): ##STR1## wherein Z represents CH.sub.2 OX or H, X represents an alkyl group, a cycloalkyl group, a substituted or unsubstituted aralkyl group or aryl group, or --COR group where R represents an alkyl group or a substituted or unsubstituted aryl group,in a recording layer which contains a leuco dye and a color-developing agent which reacts with said dye so as to form a color by heating, and the thermosensitive recording material having high color sensitivity can be obtained.

Abstract: The present invention relates to a color forming solution including the benzoin derivatives as a sensitizer.

Abstract: Disclosed is a heat-sensitive recording material comprising a support and a heat-sensitive recording layer provided on the support, the heat-sensitive recording layer comprises a dye precursor, a developer, a binder and an aromatic compound represented by the following structural formula: ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 are independently hydrogen atoms or lower alkyl groups; R.sup.4, R.sup.5 and R.sup.6 are independently hydrogen atoms, alkyl groups, cycloalkyl groups, alkoxy groups, halogen atoms, aralkyl groups, aryl groups, acyl groups, formyl groups, nitro groups or cyano groups; and X.sup.1 and X.sup.2 are oxygen atoms or sulfur atoms. This heat-sensitive recording material is excellent in heat responsiveness and sensitivity, and cause little thermal head stain.

Abstract: An extracted and isolated soy protein polymer is used for prevention of premature coloration in CFB pressure-sensitive copying paper which is neutral- or alkaline-sized with an alkyl ketene dimer and which utilizes an acid clay color developer composition. The soy protein polymer may be carried by the base paper, e.g. as a result of size press or size bath application, or may be present in the microcapsule coating.

Abstract: A heat-sensitive recording material which comprises a color-forming layer containing a coupling substance which is usually colorless or light-colored and a developer which gives rise to color in the coupling substance upon heating, wherein the color-forming layer contains an organic phosphate, its metal salt or its basic salt of the following general formula (I): ##STR1## wherein R.sub.1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R.sub.2 and R.sub.3 each represent a hydrogen atom or an alkyl group having 1 to 9 carbon atoms, M represents a hydrogen atom or a metal atom having a valence of 1 to 4, L represents 0 or 1, m, represents a number of 0 to 1, n represents 1 or 2, and m+n represents the valence of the metal M.

Abstract: Novel heat-sensitive recording media include a support substrate, e.g., paper or a synthetic polymer film, having a thermosensitive recording layer deposited thereon, such thermosensitive recording layer comprising a colorant precursor, a heat-sensitive developer therefor and at least one polyphenylmethane of the formula (A1): ##STR1## in which R.sub.1 and R.sub.2, which may be identical or different, are each a halogen atom, NO.sub.2, CN, OCH.sub.3, H or an alkyl radical having up to 5 carbon atoms; n is 3, 4 or 5; p is 1, 2 or 3; g is 0 or 1 and the maximum value of p+g is 2; and the melting point of which polyphenylmethane being at least 50.degree. C.

Abstract: Thermally-responsive record materials are described containing a "complex" material formed from interactions at high pH between zinc stearate and ammonia and/or zinc stearate, ammonia and zinc oxide. The use of these materials in thermally-responsive sheets improves thermal image response and/or improves resistance to thermal image decline upon exposure to elevated temperature.

Abstract: An improved heat-sensitive recording material is disclosed comprising a substrate, a binder, a chromogenic material, an electron-accepting color developer which reacts with said chromogenic material to form a color, and a color-stabilizing resin. The color stabilizing resin comprises an addition product of a diolefinic alkylated or alkenylated cyclic hydrocarbon or, an addition product of a phenol and a diolefinic alkylated or alkenylated cyclic hydrocarbon. The color-stabilizing resin, dye, and developer, have a weight percent resin phenolic group of about 5 or less. The heat-sensitive recording material has a fade index greater than 45. Imaged recording materials according to the invention resist fading when exposed to temperatures of 60.degree. C. for prolonged periods such as twenty-four hour oven tests.

Abstract: A reversible thermosensitive recording material is composed of a support and a reversible thermosensitive recording layer formed on the support. The reversible thermosensitive recording layer includes a matrix resin and an organic low-molecular-weight material dispersed in the matrix resin, and has a temperature-dependent transparency. The matrix resin includes a resin component having a glass transition temperature of 90.degree. C. or more.

Abstract: A thermosensitive recording material comprising a substrate and a thermosensitive coloring layer, formed thereon, which comprises a leuco dye; at least one color developer selected from the group consisting of 1,5-bis(4-hydroxyphenylthio)-3-oxapentane and 1,7-bis(4-hydroxyphenylthio)-3,5-dioxapentane; and an isocyanuric acid derivative of the formula (I): ##STR1## wherein R.sup.1, R.sup.3, R.sup.4 and R.sup.5 independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, provided that at least either R.sup.1 or R.sup.3 represents an alkyl group having 1 to 4 carbon atoms; and R.sup.2 represents --C.sub.n H.sub.2n OH in which n is an integer of 0 to 4.

Abstract: A reversible thermosensitive recording material is composed of a support and a reversible thermosensitive recording layer formed thereon, which is capable of recording and erasing images repeatedly by utilizing its property that the transparency can be changed reversibly from a transparent state to an opaque state, and vice versa, depending upon the temperature thereof. The reversible thermosensitive recording layer is composed of a reversible thermosensitive layer and a protective layer formed thereon and has a scratching intensity of 10 g or more and a coefficient of friction of 0.10 or less. Images are reversibly formed and erased on this reversible thermosensitive recording material.

Abstract: Pressure-sensitive and heat-sensitive record materials are described comprising a substrate, an acidic developer and chromogenic di-[bis-(indolyl) ethylenyl]tetrahalophthalides of the formula ##STR1## wherein each X.sup.1, S.sup.2, X.sup.3, and X.sup.4 is independently selected from chlorine or bromine;wherein each of R.sup.1 and R.sup.7 is independently selected from cycloalkyl, aralkyl, alkoxyalkyl, or aroxyalkyl;wherein each of R.sup.2 and R.sup.8 is independently selected from alkyl (C.sub.1 -C.sub.8) or aryl (substituted or unsubstituted);wherein each of R.sup.3, R.sup.4, R.sup.5, R.sup.6,R.sup.9, R.sup.10, R.sup.11, and R.sup.12 is independently selected from hydrogen alkyl (C.sub.1 -C.sub.8), cycloalkyl, aryl (substituted or unsubstituted), halogen, alkoxy (C.sub.1 -C.sub.8), aroxy, cycloalkoxy, dialkylamino including symmetrical and unsymmetrical alkyl (C.sub.1 -C.sub.

Abstract: An imaging medium has at least one color-forming layer comprising a thermal color-forming composition adapted to undergo a change of color upon increase in the temperature of the color-forming layer above a color-forming temperature for a color-forming time, the color-forming layer further comprising a color stabilizer which is a hindered amine light stabilizer or a nitrones. The color stabilizer prevents development of color in the medium during storage before or after imaging, thereby reducing the minimum optical density of the imaged medium and/or color distortion in the image.

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: A heat-sensitive recording material is obtained by coating an aqueous dispersion which is prepared by mixing an aqueous dispersion of an electron donating colorless dye with an aqueous dispersion of an electron accepting compound on a base sheet. The aqueous dispersion of an electron donating dye is prepared by a method which comprises the steps of uniformly dispersing at least one electron donating colorless dye and at least one heat-fusible substance selected from the group consisting of 2-benzyloxynaphthalene, parabenzyl biphenyl, 1,4-bis(2-vinyloxyethoxy)benzene, bis [2-(4-methoxyphenoxy)ethyl] ether, 1,2-bis (3-methylphenoxy)ethane, 1,2-diphenoxyethane, benzyl 4-methylthiophenyl ether, 1-(2-methylphenoxy)-2-(4-methoxyphenoxy)ethane and oxalic acid dibenzyl ester with a dispersing binder and/or a surface active agent in water; and pulverizing thus obtained dispersion with use of a horizontal sand mill.

Abstract: A recording material containing an electron donating colorless dye capable of undergoing a coloration reaction, wherein a metal salt of a salicylic acid derivative represented by the following formula (I) and a fatty acid derivative having a benzotriazole group as a substituent group or an alcohol derivative having a benzotriazole group as a substituent group are provided on a same support: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 represent each hydrogen atom, an alkyl group or an aryl group.

Abstract: A novel thermally-responsive record material is disclosed comprising a support having provided thereon in substantially contiguous relationship an electron donating dye precursor and a fluorene bisphenol of the formula ##STR1## wherein each R is independently selected from hydrogen and C.sub.1 to C.sub.8 alkyl,and a suitable binder therefor.The record material according to the invention when imaged resists fade when contacted with certain environmental challenges including oils, solvents, and elevated temperatures, all of which can be encountered in the environments of use of these record materials.

Abstract: A heat-sensitive recording material has a support and a color-developing layer which comprises as an organic color-developing agent 4-hydroxy-4'-n-propoxydiphenylsulfone and as a stabilizer a particular stabilizer.This heat-sensitive recording material is suitable for a high density-and speed-recording and is superior in the thermal preservability.

Abstract: A heat-sensitive recording sheet has on a support a color-developing layer which comprises a colorless or pale colored basic chromogenic dye and an organic color-developing agent, wherein the organic color-developing agent comprises both 4-hydroxy-4'-n-propoxydiphenylsulfone and a particular phenolic substance. The sheet of this invention provides excellent writing quality and superior thermal responsibility.

Abstract: The invention provides a heat-sensitive recording material comprising (a) a base sheet and (b) a heat-sensitive recording layer formed on the base sheet and comprising a colorless or pale-colored basic dye, a color developing material which develops a color on contact with the dye, and a heat-fusible material, the recording material being characterized in that the basic dye comprises 3-di(n-butyl)amino-6-methyl-7-phenylaminofluoran, and that the heat-fusible material comprises di(p-methylbenzyl) oxalate.

Abstract: A thermosensitive recording material with a highly improved dynamic coloring sensitivity, comprising a support, and a coloring layer formed thereon, which comprises (a) a leuco dye, (b) at least one of 1,7-bis(4-hydroxphenylthio)-3,5-dioxahepetane and 1,5-bis(4-hydroxyphenylthio)-3-oxapentane as a color developer, and (c) a dibenzyl oxalate derivative having formula (I) as a sensitizer: ##STR1## wherein R.sup.1 and R.sup.2 each independently represent hydrogen, an alkyl group having 1 to 4 carbon atoms, a halogen or a hydroxyl group.

Abstract: The present invention provides the following 3 types of reversible thermosensitive recording materials:1. A reversible thermosensitive recording material having a thermosensitive layer whose transparency reversibly changes depending on its temperature, said layer comprising a resin matrix and an organic low molecular substance dispersed in said resin matrix;2. A reversible thermosensitive recording material having a thermosensitive layer that is consisted essentially of a resin matrix and an organic low molecular substance dispersed in this resin matrix and is arranged to change its transparency reversibly depending upon temperatures, wherein said thermosensitive layer further contains at least one additive; and3.

Abstract: A novel thermally-responsive record material is disclosed comprising a support having provided thereon in substantially contiguous relationship an electron donating dye precursor and a succinimide of the formula ##STR1## wherein n is an integer from 1 to 3 wherein each R is independently selected from hydrogen and C.sub.1 to C.sub.8 alkyl,and a suitable binder therefor.The record material according to the invention when imaged resists fade when contacted with certain environmental challenges including oils, solvents, and elevated temperatures, all of which can be encountered in the environments of use of these record materials.

Abstract: The present invention relates to a heat-sensitive recording sheet which comprises a support, an undercoat layer provided on said support and a heat-sensitive color forming layer provided on said undercoat layer, said heat-sensitive color fomring layer containing a colorless or palely colored dye precursor, a developer which reacts with said dye precursor upon application of heat to cause said dye precursor to form color, N-methylolbehenic acid amide, and at least one sensitivity enhancing agent. This heat-sensitive recording sheet is excellent in heat responsiveness, high in sensitivity and superior in mechanical matching properties.

Abstract: A heat-sensitive recording material comprises a recording layer formed on a base sheet where the recording layer comprises a colorless or pale colored basic chromogenic material, a color developing material which develops a color by contacting with said chromogenic material, and a stabilizer.

Abstract: A process for dispersing particles of an organic commpound in water is disclosed, which comprises dispersing the organic compound in water using (1) a water-soluble high molecular weight compound having a molecular weight of at least 10,000 and (2) a copolymer formed from a monomer represented by the following formula (I) and a monomer represented by the following formula (II), said copolymer having a molecular weight of not more than 10,000: ##STR1## wherein M.sub.1 and M.sub.2 each represents an alkali metal atom or an ammonium group; R.sub.1 represents a hydrogen atom, a methyl group, or an ethyl group; and R.sub.2 represents an alkyl group having from 2 to 18 carbon atoms.

Abstract: The present invention provides a heat-sensitive recording material excellent in image stability and heat-responsiveness which contains an aromatic isocyanate compound, an imino compound and at least one compound represented by the following formula (I): ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each represents an alkyl group.

Abstract: A high solids contents, aqueous-based, self-contained printing ink is provided including, a non-volatile diluent, an acidic color developer, a binder, and a water soluble surfactant which is compatible with the binder in the ink, but which is incompatible with the binder when the ink has dried. The high solids, self-contained printing ink further includes microcapsules containing a dyestuff precursor that is capable of reacting with the acidic color developer to form a color. The ink may be used to prepare self-contained carbonless copy sheets.

Abstract: A heat-sensitive recording material which comprises a support and a heat-sensitive recording layer provided on the support, the heat-sensitive recording layer comprising a colorless or pale-colored dye precursor, a developer which reacts with the dye precursor to form color upon heating, and two compounds represented by the following formulas (I) and (II): ##STR1## The heat-sensitive recording material causes little fogging and generates little thermal head scum while having almost the same sensitivity and image stability as conventional heat-sensitive recording materials.

Abstract: The present invention provides a heat sensitive recording material which comprises an aromatic isocyanate compound, an imino compound which reacts with said aromatic isocyanate compound upon application of heat to form a color and a metallic soap which is pulverized together with said imino compound. Preferably the metallic soap has an average particle diameter of 0.5-2.0 .mu.m. This heat sensitive material is excellent in sensitivity and can form an image or excellent stability.

Abstract: A heat-sensitive recording medium comprising, on a support, a heat-sensitive color-developing layer containing a colorless or light-colored leuco dye (or an electron-donating dye precursor) and a color-developing agent (or an electron-accepting substance) reacting with the leuco dye to develop color as main constituents, said leuco dye being a compound represented by the formula (I): ##STR1## wherein X represents CH.sub.3 --(CH.sub.2).sub.3 --CH.sub.2 or CH.sub.3 --CH.sub.2 --CH.sub.2 and Y represents CH.sub.3 --(CH.sub.2).sub.3 --Ch.sub.2 or CH.sub.3, and said heat-sensitive color-developing layer containing at least one of the compounds represented by the general formula (II) and (III): ##STR2## where R.sub.1, R.sub.1 ' are respectively any one of H, Cl, and CH.sub.3, and may be the same with or different from each other: ##STR3## where R.sub.2, R.sub.2 ' are respectively any one of H and CH.sub.3, and may be the same with or different from each other.

Abstract: Compounds of the formula IU--SOL).sub.n ' (I)in which n' is a number from 1 to 4, U is a radical of a UV absorber of the hydroxyphenylbenzotriazole, hydroxybenzophenone, cinnamic acid or triazine type and SOL is a group of the formula Ia ##STR1## The symbols in the formula Ia are as defined in claim 1. The compounds, which are in part novel, are suitable for use as light stabilizers, particularly for recording materials and inks for ink jet printing.

Abstract: There is disclosed a heat sensitive recording material comprising a color-forming agent consisting of an aromatic isocyanate compound and an imino compound, and a phenol compound; said recoridng material being excellent in storability of image and storability of non-image area as well.

Abstract: The heat-sensitive record material, in which color images are produced by a color-forming reaction between a colorless or pale colored basic chromogenic material and a color developer, comprises a novolac-type epoxy resin or a diphenyl sulfone derivative represented by the formula (III) in the color forming reaction system.In the former case, it is preferable to use a novolac-type epoxy resin represented by the formula (I) together witha a compound represented by the formula (II) and, in the latter case, the desired effects can be obtained by using 3-dibutylamino-6-methyl-7-phenylaminofluoran as the basic chromogenic material. ##STR1## wherein X is halogen or alkyl having C.sub.1 to C.sub.5, and a is an integer of 0 to 4; and n is an integer of 0 to 20, each of R.sub.1 .about.R.sub.6 is hydrogen, halogen, C.sub.1-5 alkyl or C.sub.1-5 alkoxyl, R.sub.7 is ##STR2## R.sub.10 is hydrogen or alkyl; each of p and q is 0 or an integer of 1 to 5; each of r and s is an integer of 1 to 5; each R.sub.8 and R.sub.

Abstract: A heat-sensitive recording material that utilizes the color forming reaction between at least one basic dye and a developer that is capable of forming a color upon contact with said basic dye is characterized in that the heat-sensitive recording layer of said material contains both dihydroxydiphenyl ether represented by the formula (I): ##STR1## and a compound represented by the general formula (II): ##STR2## (where R is H or C.sub.n H.sub.2n+1, with n being an integer of 1-5). This heat-sensitive recording material has a sufficiently high sensitivity for color formation to kake it suitable for use in a broad range of practical applications and it also exhibits enhanced keeping quality and whiteness.

Abstract: A heat-sensitive recording material wherein a color-forming layer comprising a coupling substance which is usually colorless or light-colored and a developer which gives rise to color in the coupling substance upon heating further contains, as a sensitizer, a tetrahydronaphthalene compound of the following general formula (I): ##STR1## wherein X represents an alkylene group, --O--CO--O--, --O--CO-- or --O--R'.sub.n Y--, n represents 1 or 2, Y represents --O-- or --S--, R' represents an alkylene group, and R represents a phenyl, alkylphenyl or tetrahydronaphthyl group.

Abstract: Thermally sensitive record material (thermal paper) using 2,2-bis(4-hydroxyphenyl)-4-methylpentane as co-reactant with conventional electron donating chromogenic compounds and a combination of a long chain fatty acid amide was melting between 80.degree. and 140.degree. C. and a sensitizer melting between 60.degree. and 120.degree. C. and selected from diaryl ethers, acetoacetic anilides, phenyl hydroxynaphthoates, aryl or aralkyl substituted biphenyls and diaryl carbonates have high thermal sensitivity and good background whiteness.

Abstract: The object of the present invention is to provide a pressure sensitive reproducing material which allows reproduced letters or patterns to fade away automatically with the passage of time.The present invention accomplished the object by a pressure sensitive reproducing material composed of a colored material supported on a substrate, in which the colored material comprises a phthalein group indicator which is color-developed by an inorganic weakly basic substance jointly used with an organic amine and contains hygroscopic material or drying inhibitor.

Abstract: A heat-sensitive recording sheet of this invention comprises in a heat-sensitive color-developing layer both 4-hydroxy-4'-n-propoxydiphenylsulfone as an organic color-developing agent and a particular fluorane-leuco dye. This sheet provides an intense, clear image, less discoloration, and stable brightness.

Abstract: A heat sensitive coating has a colorless or light colored leuco dye precursor, preferably having a five-membered spirol lactone ring at one end of the molecule, and a tertiary amino group at another end of the molecule, and a developer. Sensitizers which increase the heat sensitivity of these dye precursors, and compositions of sensitized dye/developer systems are disclosed. The sensitizers are .gamma.-substituted lactones, 3-naphthylmethylidenephthalide, and derivatives of benzalphthalide.

Abstract: A heat-sensitive recording material comprising a support and a heat-sensitive recording layer provided on the support, said heat-sensitive recording layer comprising an electron-donating, colorless or pale-colored dye precursor, an electron-accepting developer which reacts with the dye precursor to form images upon heating, a binder, and a specific aromatic compound. The heat-sensitive recording material has an excellent heat responsiveness, and hence recorded images having a sufficient optical density can be printed even with low energy.

Abstract: A heat-sensitive recording material comprising a support and a heat-sensitive recording layer provided on the support, said heat-sensitive recording layer comprising an aromatic or heterocyclic isocyanate compound, an imino compound, a binder, a specific alcoholic compound, and preferably, a specific biphenyl derivative. The heat-sensitive recording material have an excellent image preservability and heat responsiveness.

Abstract: Disclosed is an acceptor coated sheet for pressure-sensitive copying system comprising a base sheet and an acceptor layer disposed thereon, said acceptor layer being formed from an acceptor coating composition comprising(a) at least one immobilizing agent selected from the group consisting of the sulfates, nitrates, acetates and formates of zinc, aluminum and magnesium,(b) a latex of copolymer containing an unsaturated carboxylic acid as a monomer component and, if necessary, a water-soluble binder,(c) an organic acceptor, and(d) at least one pigment selected from the group consisting of zinc oxide, magnesium oxide, titanium oxide, aluminum hydroxide, calcium carbonate, calcium sulfate and kaolin.

Abstract: Disclosed is a heat-sensitive recording material comprising an aromatic isocyanate compound, an imino compound which reacts with said aromatic isocyanate compound upon application of heat to form color, and a support, wherein a coating color comprising a dispersion obtained by pulverizing a mixture of said aromatic isocyanate compound and an alcoholic compound has been coated on the support. This heat-sensitive recording material is excellent in image stability and sensitivity.

Abstract: A hydantoin compound of the formula: ##STR1## (wherein R stands for an alkyl group of 8 to 20 carbon atoms) increases the sensitivity of a color developing reaction of a heat-sensitive recording material and enhances the high-speed recording property of the recording material without sacrifice of the whiteness thereof. The heat-sensitive recording material containing the hydantoin compound is novel to the art.

Abstract: A heat sensitive recording material comprising a substrate and a 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 being characterized in that, as the color acceptor is used at least one compound selected from the group consisting of 4-hydroxy-4'-isopropyloxydiphenylsulfone, 4,4'-(1,3-dimethylbutylidene) bisphenol, 4,4'-(1-phenylethylidene)bisphenol, 4,4'-(p-phenylenediisopropylidene)bisphenol and 4,4'-(m-phenylenediisopropylidene) bisphenol, and to the recording layer is added at least one of a heat-fusible substance represented by the formula [I] ##STR1## wherein X is hydrogen atom, halogen atom, C.sub.1.about.4 alkyl or C.sub.1.about.4 alkoxy.

Abstract: A heat sensitive recording material comprising 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 being characterized in that the material has a heat sensitive recording layer having incorporated therein (1) a heat-fusible substance exhibiting a weight reduction of at least 5% at 200.degree. C. based on the weight at 25.degree. C. under the condition of 20.degree. C./min in the rate of rise of temperature, (2) a wax, (3) a lubricant, and (4) an oil-absorbing pigment at least 85 ml/100 g in oil absorption.

Abstract: A heat-sensitive recording material with an excellent recording sensitivity and capable of recording thereon high quality images at a high recording speed, comprising a heat-sensitive color-forming layer formed on a substrate sheet and comprising a colorless dye precursor, a color-developing agent, a binder and a sensitizing agent consisting essentially of 1,2-diphenoxybenzene.