JP2019048411A - Heat-sensitive recording material using diphenylmethane derivative - Google Patents

Abstract

To provide a heat-sensitive recording material using a diphenylmethane derivative satisfying all required performances as a heat-sensitive recording material such as color optical density, whiteness, and maintainability of a printed part, and containing no phenol compound which has concerns on environmental hygiene.SOLUTION: In a heat-sensitive recording material in which a heat-sensitive recording layer containing a leuco dye and a developer is arranged on a supporter, a diphenylmethane derivative represented by the general formula (1), where R represents one of toluenesulfonyl, benzenesulfonyl, 1-naphthylsulfonyl, 2-naphthylsulfonyl, benzylsulfonyl, and ethylsulfonyl, is used as the developer.SELECTED DRAWING: None

Description

  The present invention relates to a thermosensitive recording material using a diphenylmethane derivative as a developer.

  Generally, in a heat-sensitive recording material, two kinds of dispersions in which a basic dye (leuco dye) colorless to pale and an organic developer are pulverized into fine particles and dispersed in an aqueous solution at normal temperature are mixed, The heat-sensitive recording paint obtained by adding a sensitizer, a binder, a lubricant, other various additives and the like to the obtained mixture dispersion is coated on a support such as paper, plastic film, processed paper, etc. and dried. To form a thermosensitive recording layer. Color recording (printing, etc.) can be performed by applying thermal energy (Joule heat) to the formed thermal recording layer using a thermal head, a heating pen, or the like. Such thermosensitive recording materials are already widely used.

  In the heat-sensitive recording layer, the leuco dye and the organic developer are dispersed in the solid state. In this state, the two do not react, but when heat energy is applied from the outside, the two melt and contact each other, causing a reaction. This reaction causes the leuco dye to develop color.

  Many developers have been proposed as developers for heat-sensitive recording materials. For example, 4,4'-isopropylidenediphenol, 4,4'-dihydroxydiphenyl sulfone, 4-allyloxy-4'-hydroxydiphenyl sulfone, 4-hydroxy-4'-isopropyloxydiphenyl sulfone [Patent Document 1], etc. Phenolic developer; N-3-[(p-toluenesulfonyl) oxy] phenyl-N '-(p-toluenesulfonyl) urea [Patent Document 2], N- [2- (3-phenylureido) phenyl] Non-phenolic developers such as benzene sulfonamide [Patent Document 3] have been proposed.

JP 2002-052842 Japanese Patent Application Publication No. 2002-532441 WO 2014/0806615

  Performances required for the heat-sensitive recording material include the whiteness of the unprinted area, the stability of the whiteness of the unprinted area under various environmental conditions, the color density of the printed area, and the storage stability of the printed area. In particular, it is required that the storability of the printing unit be high. Examples of the storage stability of the printed portion include heat resistance, moist heat resistance, light resistance, oil resistance, water resistance and plasticizer resistance.

  However, phenolic color developers do not have sufficient storage stability for printed and non-printed parts, and more recently, 4,4'-isopropylidenediphenol and 4,4'-bisphenol sulfone have As environmental health problems such as mutagenicity have been pointed out, non-phenolic developers free from these problems are required.

  Although non-phenolic color developer N-3-[(p-toluenesulfonyl) oxy] phenyl-N '-(p-toluenesulfonyl) urea (Patent Document 2) has improved color sensitivity and storage stability Not enough, there is a need for further improvement. Furthermore, N-3-[(p-toluenesulfonyl) oxy] phenyl-N '-(p-toluenesulfonyl) urea is derived from toluenesulfonylurea group derived from toluenesulfonyl isocyanate and toluenesulfonyl chloride Although it has two functional groups of an aromatic sulfonic acid aryl ester group and the aromatic sulfonic acid aryl ester group is stable to water, one toluenesulfonylurea group is originally as a protective group such as an amino group Although it has been used, it has the disadvantage of being easily hydrolyzed by water.

  On the other hand, N- [2- (3-phenylureido) phenyl] benzenesulfonamide (Patent Document 3) is not sufficiently satisfactory in terms of the required performance as a heat-sensitive recording material, and in particular, it is further enhanced in the storability of the printed part. Improvement is required.

  The present invention has been made in view of the above circumstances and is a phenolic compound which satisfies the required performance as a thermosensitive recording material such as color density, whiteness and storability of printed area, and which causes environmental health concerns The present invention relates to a heat-sensitive recording material using a diphenylmethane derivative free of In particular, the storability (heat resistance, moisture heat resistance, light resistance, oil resistance and water resistance) of the printed portion is enhanced.

  The inventors of the present invention, as a result of intensive studies, use a diphenylmethane derivative having a specific structure as a developer of a heat-sensitive recording material to exhibit high storability of printed portions while maintaining high color density and whiteness. The present invention has been completed.

  That is, the present invention is a heat-sensitive recording material in which a heat-sensitive recording layer containing a basic dye which is colorless to pale at normal temperature and a developer is provided on a support, wherein the developer is represented by the general formula (1):

（式中、Rはトルエンスルホニル、ベンゼンスルホニル、1-ナフチルスルホニル、2-ナフチルスルホニル、ベンジルスルホニルおよびエチルスルホニルのいずれかを表す。）で表される新規なジフェニルメタン誘導体であることを特徴とする。

Wherein R represents a novel diphenylmethane derivative represented by toluenesulfonyl, benzenesulfonyl, 1-naphthylsulfonyl, 2-naphthylsulfonyl, benzylsulfonyl and ethylsulfonyl.

  The present invention uses a diphenylmethane derivative represented by the general formula (1) as a color developer, does not contain a phenolic compound which has environmental health concerns, and prints while maintaining high color density and whiteness. It is possible to provide a thermosensitive recording material in which the storability of the part is enhanced.

FIG. 1 shows an IR chart of the compound obtained in Example 1.

  The heat-sensitive recording layer of the heat-sensitive recording material of the present invention is at least two kinds in which a colorless or pale basic dye (leuco dye) and an organic color developer are pulverized into fine particles and dispersed in an aqueous solution at room temperature. The resulting mixture dispersion is mixed with a binder, a sensitizer, a filler, a lubricant, various other additives and the like to the obtained mixture dispersion to prepare a coating for thermal recording, which is then used as a paper, plastic, or the like. It is coated on a support such as a film or processed paper and dried. For example, a binder may be added to the aqueous solution, and a sensitizer may also be mixed as a dispersion with the leuco dye dispersion and the developer dispersion.

  In the heat-sensitive recording layer of the heat-sensitive recording material of the present invention, although the leuco dye and the developer are present in independent solid states, heat is applied to the heat-sensitive recording layer using a heat-sensitive head, a heat pen or the like. By applying energy (Joule heat), the leuco dye and the developer melt and come into contact with each other. By contact between the two, the colorless or pale leuco dye causes a color reaction, and color recording (such as printing) can be performed in the area to which thermal energy is applied.

  In the heat-sensitive recording material of the present invention, the developer is a novel diphenylmethane derivative represented by the general formula (1).

  In particular, the compounds represented by the general formulas (2) and (3) are preferable because they are excellent in oil resistance.

  In the heat-sensitive recording material of the present invention, triphenylmethane dyes, fluorane dyes, diphenylmethane dyes, spiro dyes, fluorene dyes and thiazine dyes may be mentioned as colorless or light-colored basic dyes (leuco dyes) at room temperature. You can choose from dyes.

  Examples of leuco dyes that can be used in the present invention include, but are not limited to, for example, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) phthalide , 3- (4-Diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3,3-bis (p-methylaminophenyl) -6 -Dimethylaminophthalide, 3-diethylamino-7-dibenzylaminobenzo [α] fluoran, 3- (1-ethyl-2-methylindol-3-yl) -3- (4-diethylamino-2-n-) Hexyloxyphenyl-4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (4-diethylamino) -2-methylphenyl-4-azaphthalide, 3- (4-diethylaminophenyl) ) -3- (1-Ethyl-2-methylindol-3-yl) phthalide, 3- (2-methyl-1-n-octylindol-3-yl) -3- (4-diethylamino-2-) Ethoxy Phenyl) -4-azaphthalide, 3- (N-ethyl-N-isopentylamino) -6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-diethylamino -6-Methyl-7- (o, p-dimethylanilino) fluoran, 3- (N-ethyl-Np-toluidino) -6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7 -Anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluorane, 3-diethylamino- 7- (o-Chloroanilino) fluoran, 3-diethylamino-7- (m-trifluoromethylanilino) fluoran, 3-di (n-pentyl) amino-6-methyl-7-anilinofluoran, 3- [ N- (3-Ethoxypropyl) -N-ethylamino] -6-methyl-7-anilinofluorane, 3- (Nn-hexyl-N-ethylamino) -7- (o-chloroanilino) fluorane, 3 -(N-ethyl-N-2-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane, 2,2-bis {4- [6 '-(N-cyclohexyl-N-methylamino)- 3'-Methylspiro [phthalide-3,9'-xanthene] -2'-ylamino] phenyl} propane, 3-dibutylamino-7- (o-chloroanilino) fluoran, 3,6-dimethoxyfluoran, 3-pyrrolidino- 6-chlorofluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-7,8-dibenzofluoran, 3-diethylamino-6,7- Dimethylfluoran, 3- (N-methyl-p-toluidino) -7-methylfluoran, 3- (N-methyl-N-isoamylamino) -7,8-benzofluoran, 3,3'-bis ( 1-n-amyl-2-methylindol-3-yl) phthalide, 3- (N-methyl-N-isoamylamino) -7-phenoxyfluoran, 3,3′-bis (1-n-butyl- 2-methyl Ndol-3-yl) phthalide, 3,3′-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3′-bis (p-dimethylaminophenyl) phthalide, 3- (N -Ethyl-Np-tolylamino) -7- (N-phenyl-N-methylamino) fluoran, 3-diethylamino-7-anilinofluoran, 3-diethylamino-7-benzylaminofluoran, 3-pyrrolidino-7- Dibenzylaminofluoran etc. are mentioned. These leuco dyes may be used alone or in combination of two or more.

  In the present invention, conventionally known sensitizers can be used in combination. As a sensitizer which can be used in the present invention, for example, fatty acid amides such as stearic acid amide, bisstearic acid amide and palmitic acid amide; p-toluenesulfonamide, calcium such as stearic acid, behenic acid and palmitic acid, zinc Or fatty acid metal salts such as aluminum; p-benzylbiphenyl, diphenylsulfone, benzyl benyloxybenzoate, 2-benzyloxynaphthalene, 1,2-bis (p-tolyloxy) ethane, 1,2-bis (phenoxy) ethane, Fragrances such as 1,2-bis (3-methylphenoxy) ethane, 1,3-bis (phenoxy) propane, dibenzyl oxalate, p-methylbenzyl oxalate, m-terphenyl, 1-hydroxy-2-naphthoic acid Group compounds and the like.

  Furthermore, in the present invention, conventionally known storage stabilizers can be used in combination. Examples of storage stabilizers that can be used in the present invention include, but are not limited to, for example, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert) -Butylphenol), 2,2'-Ethylidenebis (4,6-di-tert-butylphenol), 4,4'-thiobis (2-methyl-6-tert-butylphenol), 4,4'-butylidenebis (6- tert-Butyl m-cresol), tris (2,6-dimethyl-4-tert-butyl-3-hydroxybenzyl) isocyanurate, 4,4'-thiobis (3-methylphenol), 4,4'-dihydroxy- 3,3 ', 5,5'-tetrabromodiphenyl sulfone, 4,4'-dihydroxy 3,3', 5,5'-tetramethyldiphenyl sulfone, 2,2-bis (4-hydroxy-3,5-) Dibromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propa Hindered phenol compounds such as: 1,4-diglycidyl oxybenzene, 4,4′-diglycidyl oxydiphenyl sulfone, 4-benzyloxy-4 ′-(2-methylglycyloxy) diphenyl sulfone, glycidyl terephthalate Epoxy compounds such as bisphenol A type epoxy resin type, cresol novolac type epoxy resin, phenol novolac type epoxy resin; N, N'-di-2-naphthyl-p-phenylenediamine, 2,2'-methylene bis (4,6 Sodium salt or polyvalent metal salt of di-tert-butylphenyl) phosphate; bis (4-ethyleneimine carbonylaminophenyl) methane; and further, general formula (4):

（式中、ｎは、１〜７の整数である。）で表されるジフェニルスルホン架橋型化合物等が挙げられる。

(In the formula, n is an integer of 1 to 7). Examples thereof include diphenylsulfone crosslinkable compounds and the like.

  Moreover, as the auxiliary agent, for example, dispersants such as, but not limited to, sodium dioxothiolsuccinic acid, sodium dodecylbenzene sulfonate, sodium lauryl alcohol sulfate, fatty acid metal salt, etc .; zinc stearate, calcium stearate, polyethylene wax, Waxes such as carnauba wax, paraffin wax, ester wax; Hydrazide compounds such as adipic acid dihydrazide; Water resistant agents such as glyoxal, boric acid, dialdehyde starch, methylol urea, glyoxylate, epoxy compounds, etc. Antifoaming agent Dyes; fluorescent dyes; and pigments.

  As the binder used in the heat-sensitive recording layer in the present invention, the degree of polymerization of completely saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, carboxy modified polyvinyl alcohol, amide modified polyvinyl alcohol, sulfonic acid modified polyvinyl alcohol, butyral modified polyvinyl alcohol, etc. Polyvinyl alcohols of 200 to 1900; hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer and cellulose derivatives such as ethyl cellulose and acetyl cellulose; polyvinyl acetate, polyacrylamide, polyacryl Acid ester, polyvinyl butyral polystyrol and their copolymers; polyamide resin; silicone resin; petroleum resin Terpene resins; ketone resins; and chroman resins. These binders may be used alone or in combination of two or more, and may be used by being dissolved in a solvent, or in a state of being dispersed in water or other medium in the form of emulsion or paste.

  The pigment to be blended in the heat sensitive recording layer is silica, calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, talc, titanium oxide, zinc oxide, aluminum hydroxide, polystyrene resin, urea-formalin resin, styrene-methacrylic acid copolymer And inorganic or organic pigments such as styrene-butadiene copolymer and hollow plastic pigment.

  The types and amounts of basic dyes, developers, sensitizers, binders, pigments and other additives used in the heat-sensitive recording layer in the present invention are appropriately determined according to the quality performance required of the heat-sensitive recording layer. It is determined.

  In the heat-sensitive recording layer according to the present invention, the content of the diphenylmethane derivative represented by the above general formula (1) as a developer is 0 based on 1 part by mass of the basic dye of the heat-sensitive recording layer from the viewpoint of coloring density. The amount is preferably 3 to 5 parts by mass, and more preferably 0.4 to 3 parts by mass.

  Furthermore, the sensitizer is suitably 0.2 to 4 parts by mass with respect to 1 part by mass of the leuco dye, and the binder is suitably 5 to 50% by mass in the total solid content. As the support, paper, recycled paper, synthetic paper, plastic film, non-woven fabric, metal foil and the like can be used. Also, a composite sheet combining these may be used.

  Moreover, you may provide the overcoat layer which consists of a polymeric substance containing an organic pigment in order to improve shelf life. Furthermore, an undercoat layer containing an organic pigment, an inorganic pigment, hollow fine particles, foam particles and the like may be provided for the purpose of preventing adhesion of wrinkles to the thermal head, improving printing image quality, and improving sensitivity.

  The leuco dye, the developer, the sensitizer and, if necessary, the storage stabilizer used in the thermosensitive recording layer in the present invention may be prepared, for example, by using water as a dispersion medium and stirring particles such as a ball mill, attritor and sand mill. It is finely dispersed and used so that the diameter is 2 μm or less.

  If necessary, the pigment, binder, auxiliary agent, etc. are mixed and stirred in the dispersion containing the mixture of the finely dispersed leuco dye, the developer, the sensitizer and, if necessary, the storage stabilizer, for thermal recording. Prepare the paint.

The coating for thermal recording prepared in this manner is coated on a support so that the coating amount after drying is about 1.5 to 12 g / m ² , more preferably about 3 to 7 g / m ^2. By drying, a thermosensitive recording layer is formed.

  Hereinafter, the present invention will be specifically described by way of Examples and Comparative Examples, but the present invention is not limited thereto. In the examples, "parts" and "%" represent "parts by mass" and "% by mass".

Example 1
[Creating paint for undercoat]
100 parts of plastic hollow particles (trade name: low-peak SN-1055: hollow ratio: 26.5% solid content) 100 parts of a 50% dispersion of calcined kaolin, styrene-butadiene latex (trade name: L-1571 solid) 25 parts of water, 50 parts of a 10% aqueous solution of oxidized starch and 20 parts of water were mixed to prepare an undercoat paint.

[Synthesis of developer]
In a 300-ml three-necked flask, 10.3 g of 3- (p-toluenesulfonyloxy) aniline and 150 g of THF were charged, and the internal temperature was adjusted to 60.degree. 4.35 g of methylene diphenyl diisocyanate dissolved in THF was added dropwise and reacted with stirring for 5 hours. After completion of the reaction, the reaction product was cooled and the precipitated crystals were separated by filtration to obtain a compound. The compound was confirmed by IR to be di-{[3- (p-toluenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane represented by the general formula (2) (IR chart in FIG. 1 reference).

[Preparation of paint for thermal recording]
First, leuco dye 3- (N, N-dibutylamino) -6-methyl-7-anilinofluorane, a compound shown in Table 1, the developer di-{[3- (p-) obtained above Toluenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane and sensitizer 1,2-bis (m-tolyloxy) ethane are mixed with a 10% polyvinyl alcohol aqueous solution as a dispersion binder to prepare solution A (leuco dye dispersion A solution, B liquid (color developer dispersion) and C liquid (sensitizer dispersion) were prepared.

  Each of the dispersions of solution A, solution B and solution C was ground with a sand grinder to an average particle size of 1 μm or less, and the obtained dispersions were mixed in the proportions shown in Table 2 to obtain a mixture dispersion. .

  27 parts of aluminum hydroxide (trade name: HYGILITE H-42), 10 parts of amorphous silica (trade name: Mizukasil P-527), and 100 parts of a 10% solution of starch oxide in 165 parts of the obtained mixture dispersion A composition for thermal recording was prepared by mixing a composition comprising 19.4 parts of zinc stearate dispersion: (trade name: Hydrin Z-8-36) and 50 parts of water.

[Preparation of thermosensitive recording material]
An undercoat paint is coated and dried on a high quality paper (acidic paper) having a basis weight of 53 g as a support so that the mass per area after drying is 6 g / m ² to form an undercoat layer, and A heat-sensitive recording material was applied to the undercoat layer so as to have a weight per area after drying of 3.8 g / m ² and dried to form a heat-sensitive recording layer. The obtained sheet was treated with a super calender so that the smoothness (JISP 8155: 2010) became 900 to 1200 s to prepare a thermosensitive recording material, and various tests were conducted.

[Various tests]
1. Hydrolyzability (water stability test)
The developer of the present invention is dissolved in a mixed solution of acetonitrile and water (acetonitrile / water = 80/20 volume ratio) in an amount of 0.5% by weight, and stirred for 5 hours at 50 ° C. Manufactured by high performance liquid chromatography (detection wavelength: 205 nm).
If the decomposition amount is 1% or more, the stability is bad (x), and if it is 1% or less, the stability is judged to be good (o).

2. Thermal Recording Property Test A thermal recording material prepared using the developer of the present invention was printed using a thermal recording paper printing tester (TH-PMD manufactured by Okura Electric Co., Ltd.) with an applied energy of 0.38 mJ / dot. The image density of the printed portion and the density of the unprinted portion of the test piece were measured with a Macbeth reflection densitometer RD-914.

3. Heat resistance test In a thermosensitive recording test, a thermosensitive recording material printed with an applied energy of 0.38 mJ / dot is left in a constant temperature environment of a test temperature of 60 ° C. for 24 hours, and then the image density of the printed portion of the test piece and the density of the unprinted portion Was measured with a Macbeth reflection densitometer.

4. Heat-and-moisture resistance test In a thermosensitive recording test, a thermosensitive recording material printed with an applied energy of 0.38 mJ / dot is left for 24 hours under the environment of a test temperature of 40 ° C. and 90% RH, and then the image density and unprinted area of the printed portion of the test piece The density of the part was measured with a Macbeth reflection densitometer.

5. Light resistance test A thermal recording material printed with an applied energy of 0.38 mJ / dot in a thermal recording test is exposed to 5000 Lux for 100 hours, and then the image density of the printed area of the test piece and the density of the unprinted area are measured with a Macbeth reflection densitometer did.

6. Oil resistance test Immersed in salad oil for 10 minutes in a thermosensitive recording material printed at an applied energy of 0.38 mJ / dot in a thermosensitive recording test, wiped off the oil of the test piece, and then printed the image density and unprinted portion of the test piece The density of the part was measured with a Macbeth reflection densitometer.

7. Water resistance test A thermal recording material printed with an applied energy of 0.38 mJ / dot in a thermal recording test is immersed in water for 15 hours and the test piece is air dried, and then the image density of the printed portion and the density of the unprinted portion of the test piece Was measured with a Macbeth reflection densitometer.

8. Plasticizer resistance test A thermal recording material in which a wrap film (trade name: Hi-rap KMA made by Mitsui Chemicals) is triple wound on a polycarbonate pipe (diameter 48 mm) and printed with an applied energy of 0.38 mJ / dot in the thermal recording test. After placing the film on it and wrapping it in triple wrap of a wrap film and leaving it for 24 hours under an environment of 20 ° C./65% RH, the image density of the printed part of the test piece and the density of the unprinted part were measured by Macbeth reflection densitometer .

(Example 2)
The same procedure as in Example 1 is carried out except that 10.3 g of 3- (p-toluenesulfonyloxy) aniline is replaced with 9.70 g of 3- (phenylsulfonyloxy) aniline in the synthesis of the developer of Example 1. The compound di-{[3- (benzenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane represented by the general formula (3) was synthesized.
Di-{[3- (p-toluenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane used in solution B of Example 1 di-{[3- (benzenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane The same operation as in Example 1 was carried out except that (the compound represented by the general formula (3)) was used to prepare a thermosensitive recording material, and various tests were conducted.

(Example 3)
The same procedure as in Example 1 was repeated except that 10.3 g of 3- (p-toluenesulfonyloxy) aniline was replaced with 11.65 g of 3- (1-naphthalenesulfonyloxy) aniline in the synthesis of the developer of Example 1. Conducted to synthesize di-{[3- (1-naphthalenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane.
Di-{[3- (p-toluenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane in solution B of Example 1 di-{[3- (1-naphthalenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane The same operation as in Example 1 was carried out except that the heat-sensitive recording material was prepared, and various tests were conducted.

(Comparative example 1)
Example 1 and Example 1 with the exception that di-{[3- (p-toluenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane in solution B is replaced with 4,4'-isopropylidenediphenol (bisphenol A). The same operation was performed to prepare a thermosensitive recording material, and various tests were conducted.

(Comparative example 2)
Example 1 is the same as Example 1 except that di-{[3- (p-toluenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane in solution B is replaced with 4,4'-dihydroxydiphenyl sulfone (bisphenol S). The heat-sensitive recording material was prepared and subjected to various tests.

(Comparative example 3)
The same procedure as in Example 1 except that di-{[3- (p-toluenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane in solution B of Example 1 is replaced with 4-allyloxy-4'-hydroxydiphenyl sulfone The heat-sensitive recording material was prepared, and various tests were conducted.

(Comparative example 4)
Example 6 is the same as Example 1 except that di-{[3- (p-toluenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane in solution B of Example 1 is replaced with 4-hydroxy-4'-isopropyloxy-diphenyl sulfone. The heat-sensitive recording material was prepared and subjected to various tests.

(Comparative example 5)
Di-{[3- (p-toluenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane of solution B of Example 1 was converted to N-3-[(p-toluenesulfonyl) oxy] phenyl-N '-(p- The same operation as in Example 1 was performed except that toluenesulfonyl) urea was used to prepare a heat-sensitive recording material, and various tests were conducted.

(Comparative example 6)
Operation except that di-{[3- (p-toluenesulfonyloxy) phenyl] aminocarbonylamino} phenylmethane in solution B of Example 1 is replaced with N- [2- (3-phenylureido) phenyl] benzenesulfonamide The same procedure as in Example 1 was followed to prepare a heat-sensitive recording material, and various tests were conducted.

  The results of various tests of the hydrolyzability of the developer and the heat sensitive recording material in Examples 1 to 3 and Comparative Examples 1 to 6 are as described in Table 4.

  As apparent from the results in Table 4, the diphenylmethane derivative according to the present invention is not decomposed by water, and the heat-sensitive recording material prepared using the diphenylmethane derivative according to the present invention has a good whiteness and high color development. It showed the concentration, and was excellent also in all the storage stability tests of heat resistance, moist heat resistance, light resistance, oil resistance, water resistance and plasticizer resistance of the printed part.

  Since the heat-sensitive recording material of the present invention is a diphenylmethane derivative represented by the general formula (1), there is no concern about endocrine disruption, no degradability, and the color density of the printed portion is high. Because of the good whiteness of the non-printed part and the excellent shelf life obtained in all the shelf life tests, the industrial applicability as a substitute for conventional thermosensitive recording materials is very promising.

Claims (2)

A heat-sensitive recording material comprising a support and a heat-sensitive recording layer containing a colorless or pale basic dye and a color developing agent at room temperature, wherein the color developing agent has a general formula (1):

A heat-sensitive recording material which is a diphenylmethane derivative represented by (wherein R represents any of toluenesulfonyl, benzenesulfonyl, 1-naphthylsulfonyl, 2-naphthylsulfonyl, benzylsulfonyl and ethylsulfonyl). The developer is represented by the general formula (2):

Or general formula (3):

The heat-sensitive recording material according to claim 1, which is a diphenylmethane derivative represented by

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