JPS62242582A - Thermal recording material - Google Patents

Abstract

PURPOSE:To contrive the enhancement of preservation stability and recording sensitivity of a recording material before printing or fixation, by incorporating a sulfonamide compound having a specified melting point into a recording layer. CONSTITUTION:A sulfonamide compound of formula [I] having a melting point of 70-180 deg.C is additionally incorporated in a recording layer, in a photo-fixable type thermal recording material having the recording layer which comprises microcapsules containing a diazonium compound therein, a coupler compound and a compound giving a basic atmosphere when being melted by heating. The compound of formula [I] has an excellent effect on enhancing preservation stability, particularly, recording sensitivity, of the recording material before fixation. In the formula, each of R1 and R2 is a lower alkyl, cycloalkyl, aryl, aralkyl or heterocyclic ring residue, and R3 is hydrogen or a lower alkyl. The alkyls in the formula may be substd. by a halogen, and aromatic rings in the formula may be substd. by a halogen, lower alkyl, lower alkoxyl, acylamino or alkylamino.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a photo-fixable heat-sensitive recording medium, and particularly to a photo-fixable heat-sensitive recording medium that has excellent recording storage stability before recording and also has good recording sensitivity. It is related to.

``Prior Art'' Conventionally, heat-sensitive technology utilizes the coloring reaction of a basic colorless dye and a coloring agent that can change color when it comes into contact with the dye, and brings a recoloring substance into contact with the dye to obtain a recorded image. Records are well known.

Since such a thermal recording medium has a structure in which a recorded image is obtained by heat, there is a defect that if the heat source is mistakenly brought close even after applying heat and recording, the entire heat source will develop color, making the necessary record unreadable. have. Therefore, it has been difficult to apply it to important records that require preservation.

Therefore, as a fixable heat-sensitive recording material, a diazo-based heat-sensitive recording material that utilizes a color-forming reaction between a diazonium compound and a coupler is being developed.

Generally, in a diazo thermosensitive recording material, a diazonium compound and a coupler are dispersed in the recording layer in the form of discontinuous particles, and a coloring aid that generates alkali upon heating is used in combination to form a recorded image. The structure is such that unreacted diazonium compounds are then decomposed by light irradiation to stop color development.

However, such recording media have a strong tendency to cause background fogging (unnecessary coloring phenomenon) due to pre-coupling before printing and fixing, so improvements are desired, and various improvement methods have been proposed. A method using a highly hydrophobic guanidine derivative as a basic compound (Japanese Patent Application Laid-open No. 1983-1999)
-45094, JP-A-57-125091), a method using a water-insoluble diazonium compound (JP-A-58
55290), and a method of microencapsulating one or both of diazonium compounds, couplers, and basic compounds (Japanese Patent Application Laid-Open No. 190886/1986).

However, the thermal recording materials obtained by these improved methods have lower recording sensitivity due to improved pre-coupling before printing and fixing, making it difficult to apply them to high-speed recording devices. At present, a photofixable thermosensitive recording material that satisfies both storage stability and recording sensitivity has not yet been obtained.

``Problems to be Solved by the Invention'' The purpose of the present invention is to overcome the above-mentioned difficulties in photofixing type thermal recording materials, to provide excellent storage stability of the recording material before printing and fixing, and to improve recording sensitivity. The objective is to provide a good recording medium.

"Means for Solving the Problems" The present invention provides a photofixable thermosensitive recording material having a recording layer containing a microcapsule containing a diazonium compound, a coupler compound, and a compound that exhibits a basic atmosphere when melted by heat. In the recording layer, a melting point of 70 to 180 is further added.
This is a heat-sensitive recording material characterized by containing a sulfonamidated metal material having a temperature of .degree.

"Function" The sulfonamide compound used in the present invention is a compound having a specific melting point of 70 to 180°C as described above, but in particular, the compound represented by the following general formula [I]
It is preferably used because it has excellent storage stability of the recording medium before fixing, and particularly exhibits an excellent effect on improving recording sensitivity.

RI-S Oz -N -Rz (1) R [wherein R, and R each represent a lower alkyl group; a cyclic alkyl group; an aryl group; an aralkyl group or a heterocyclic residue, and R1 is a hydrogen atom or a lower alkyl group, in which the alkyl group contained in the formula may be substituted with a halogen atom, and the aromatic ring is substituted with a halogen atom, a lower alkyl group, a lower alkoxyl group, an acylamino group, or an alkylamino group. may have been done. ]The above general formula [I
] As a specific example of the sulfonamide compound shown,
For example, methanesulfonanilide (w+, p, 102℃
], 1-chloro-N-(1-naphthyl)-methanesulfonamide (m, p, 128°C), l-chloro-N-(
2-Naphthyl)-ethanesulfonamide (+++, p,
115°C), N-(β-iodophenethyl)-p-
Toluenesulfonamide (m, p, 137°C], N-
Cyclohexylbenzenesulfonamide [Claim, p. 91]
'e), N, N-diisobutyl-p-1 luenesulfonamide (+*, p.

110°C), N-o-)lylbenzenesulfonamide (
m, p, 108°C], N-benzyl-p-tonoleninsulfonamide (m, p, 117°C), naphthalene-
2-sulfono-2',5'-xylidide (+s, p.

118℃], N-methyl-p-)luenesulfone-〇-
Anisidide [Akebono, p, l OQ℃], methanesulfono-p-7enethidide (w+, p, 127℃), 4'-
(dimethylamino)-p-)luenesulfonani')
F (m, p, 131° C.), 6-penzenesulfonylamino-2-chloro-benzothiazole C+++, p.

176°C), N-(4-methyl-thiazol-2-yl)-p-)luenesulfonamide (m, p, 174
°C], N-morpholinomethyl-p-toluenesulfonamide (n+, p, 110 °C), but are not limited thereto.

As mentioned above, the sulfonamide compound used in the present invention is selectively used as a compound having a specific melting point of 70 to 180°C, and a compound having a melting point outside of this range may not achieve the desired effect of the present invention. It is not possible to obtain.

The amount of these compounds used is diazonium compound 1
It is desirable to adjust the amount in a range of 0.5 to 15 parts by weight, more preferably 1.0 to IO parts by weight.

The microcapsules encapsulating the diazonium compound used in the present invention can be prepared by various known methods. is prepared by forming a polymer film around oil droplets.

Specific examples of polymeric substances include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene/methacrylate copolymer, styrene/acrylate copolymer, gelatin, polyvinyl alcohol, etc. However, polyurethane and polyurea films are particularly preferably used.

For example, microcapsules whose walls are made of polyurethane,
A polyvalent isocyanate and a polyol etc. that react with it to form a wall film are mixed into the core material to be encapsulated, emulsified and dispersed in an aqueous medium in which a retentive colloid material such as polyvinyl alcohol is dissolved, and the liquid temperature is raised. It is produced by causing a polymer formation reaction at the oil droplet interface. Note that the particle diameter of the microcapsules is desirably adjusted within a range of about 0.1 to 10 μm in consideration of the recording sensitivity and the quality of the recorded image obtained.

Specific examples of core substances include phosphate esters such as tricresyl phosphate and octyl diphenyl phosphate, phthalate esters such as dibutyl phthalate and dioctyl phthalate, carboxylic acid esters such as butyl oleate, various fatty acid amides, and diethylene glycol diphthalate. Examples include benzoate, alkylated biphenyls such as isopropylbiphenyl, and chlorinated paraffins, but are not limited to these.

Various materials are known for diazonium compounds to be encapsulated in microcapsules, such as p-N,
N-dimethylaminobenzenediazonium, 4-morpholino-2,5-dibutoxybenzenediazonium, 4-
Morpholino-2,5-diisopropoxybenzenediazonium, 4-(4'-methoxybenzoylamino")-
2,5-Jethoxybenzenediazonium, 4-morpholinobenzenediazonium, 4-pyrrolidino-3-methylbenzenediazonium, p-N-ethyl-N-hydroxyethylanilinediazonium, 4-benzamide-
2,5-jethoxybenzenediazonium, 2-N,N
-Diethyl-m-toluidine diazonium, 6-morpholino-m-)luidine diazonium, etc., such as tetraphenyl boron salts, tetrafluoroboron salts, phosphorus hexafluoride salts, etc., among which phosphorus hexafluoride salts are particularly preferred. used.

These diazonium compounds are used by being dissolved or mixed with -a in an organic solvent which is a core substance at a concentration of 1 to 50% by weight.

The coupler compound used in combination with the thus prepared microcapsules containing a diazonium compound is a material that forms a dye through a coupling reaction with the diazonium compound in a basic atmosphere, and specific examples include resorcinol, catechol, and phloroglucin. , α-naphthol,
1. 5-Shihi l'loxinaphthalene, 2.5-dimethyl-4-morpholinomethylphenol, sodium l-hydroxynaphthalene-4-sulfonate, N-(3-morpholinopropyl)-3-hydroxy-2-naphthamide, 2- Hydroxy-3-(β-hydroxyethylamide carbonyl)naphthalene, 2-hydroxynaphthalene-3-carbonyldiethanolamine, sodium 2-hydroxynaphthalene-3,6-disulfonate, acetoacetanilide, 3-methyl-5-pyrazolone, 1- Phenyl-3-methyl-5-pyrazolone, 2-hydroxy-3-naphthoic acid hydroxyethylamide, 2-hydroxy-3-naphthoic acid anilide, 2-hydroxy-3-naphthoic acid-α-naphthalide, 2-hydroxy-3-naphthoic acid- β-naphthalide, 2-hydroxy-3-naphthoic acid-4
'-Chloroanilide, 2-hydroxy-3-naphthoic acid-
4'-fluoroanilide, 2-hydroxy-3 naphthoic acid-2', 6'-dichloroanilide, 2-hydroxy-3
Naphthoic acid-2',6'-dichloroanilide, 4.4'
-di-0-acetoacetotoluide, benzoylacetanilide, etc., but are not limited to these, of course, and two or more types can also be used in combination.

The amount of the coupler compound to be incorporated into the recording layer varies depending on the type of compound used, so it cannot be determined unconditionally, but it is from 0.1 to 1 part by weight of the diazonium compound in
It is blended in an amount of about 10 parts by weight, more preferably about 0.3 to 5 parts by weight.

The compound used in the present invention, which exhibits a basic atmosphere during heat melting, is not particularly limited as long as it generates alkali when heated, and various heat-melting basic compounds are preferably used. For example, organic ammoniums, organic amines, ureas, isoureas,
Examples include nitrogen-containing compounds such as pyridines, piperazines, guanidines, imidazoles, imidacillines, triazoles, morpholines, piperidines, amidines, and pyridines.

Among these, guanidines and amidines are particularly preferred, and specifically, for example, 1,3-diphenylguanidine,
1.3-di0-)ylguanidine, 1.2.3-triphenylguanidine, 1゜3-dicyclohexyl-2-
Phenylguanidine, 1.2.3-)dichlorohexylguanidine, N.

N'-diphenylacetamidine, N,N'-bis(p
-tolyl)acetamidine, N,N'-diphenylpropionamidine, N,N'-diphenylcaprylamidine, N,N'-diphenyl-2-naphthyl (1)acetamidine, 3. N,N'-triphenylbropionamidine, N,N'-diphenylbenzamidine, N,N'
-diphenyl-p-anisamidine, N,N'-bis(
p-chlorophenyl)benzamidine N, N #
, N/#.

N-tetraphenylhexanecyamidine, N,N'N"
, N-tetrakis(p-chlorophenyl)octanecyamidine, etc., but of course the present invention is not limited to these. Moreover, two or more types of these compounds can also be used in combination.

The blending ratio of the heat-melting basic compound cannot be unconditionally determined as it varies depending on the type of compound used, but it is generally 1 to 3 parts by weight per 1 part by weight of the diazonium compound.
0 parts by weight, more preferably 5 to 15 parts by weight.

The coupler compound, the compound exhibiting a basic atmosphere when melted by heat, and the above-mentioned specific sulfonamide compound used in the present invention can be encapsulated and used in the same way as the diazonium compound, but when not encapsulated, It is preferable to use a suitable agitating and pulverizing device such as a ball mill, sand grinder, attritor, etc. so that the particle size becomes 10 μm or less.

Thus, in the present invention, a heat-sensitive recording layer containing at least one of each of microcapsules containing a diazonium compound, a coupler compound, a compound exhibiting a basic atmosphere when melted by heat, and the above-mentioned specific sulfonamide compound is formed on a support. However, such a heat-sensitive recording layer is generally formed by preparing a coating solution containing the above-mentioned substances and coating it on a support.

The coating liquid contains sodium naphthalene sulfonate, sodium naphthalene disulfonate, sulfosalicylic acid,
Preservation improvers such as magnesium sulfate and zinc chloride, antioxidants such as thiourea, diphenylthiourea, and urea, acid stabilizers such as citric acid, malic acid, tartaric acid, phosphoric acid, and saponin, starch, casein, and gum arabic. , various water-soluble or water-dispersible adhesives such as polyvinyl alcohol, polyvinyl acetate emulsion, styrene-butadiene copolymer latex, silica, clay, barium sulfate, titanium oxide,
Pigments such as calcium carbonate, as well as animal and vegetable waxes, petroleum waxes, polyhydric alcohol esters of higher fatty acids, higher fatty acid amides, condensates of higher fatty acids and amines, synthetic paraffins, chlorinated paraffins, and naphthoic acids. Various auxiliary agents such as melting point depressants such as alkyl or aryl esters are added in a vortex chamber.

The coating solution prepared in this way is coated on a suitable support such as paper, plastic film, synthetic paper, metal film, etc., but the coating method is not particularly limited and can be applied using a conventional method. For example, by using a suitable coating device such as an air knife coater, roll coater, blade coater, etc., the dry weight is about 3 to 20 g/n (at least the coating amount of the diazonium compound is 0.05 to 2.0 g).
/rd) is coated and dried.

In addition, in the recording medium of the present invention, a recorded image is formed using a thermal pen, a thermal head, etc. in the same way as a normal thermal recording medium, and then the entire surface is irradiated with ultraviolet light using a fluorescent lamp, a mercury lamp, etc., and the non-recorded portions are exposed. By decomposing unreacted diazonium compounds,
It is capable of fixing recorded images.

"Example" The present invention will be described in more detail with reference to Examples below, but it is of course not limited to these.

Further, unless otherwise specified, parts and % in the examples do not indicate parts by weight and % by weight, respectively.

Example I Preparation of Solution A Trimethylolpropane adduct of 2 parts of 4-morpholino-2,5-dibutoxybenzenediazonium phosphorus hexafluoride salt and xylylene diisocyanate (trade name Takene) D
IION (manufactured by Takeda Pharmaceutical) was dissolved in a mixed solvent of 10 parts of tricresyl phosphate and 10 parts of dibutyl phthalate, and the resulting solution was emulsified and dispersed in 70 parts of a 6% aqueous solution of polyvinyl alcohol to obtain an average particle size. An emulsion with a diameter of 8 μm was obtained.

70 parts of water was added to the obtained emulsion and reacted at 60° C. for 3 hours to prepare a microcapsule dispersion containing a diazonium compound as Liquid A.

Preparation of Solution B 2-Hydroxy-3-naphthoethyl-o-)luidide 5 parts N,N'-diphenylbenzamidine 10 parts Methanesulfono-p-phenetidide 10 parts Calcium carbonate
10% aqueous solution IQO of 20 parts polyvinyl alcohol
The above composition was dispersed in a ball mill for 48 hours to prepare Solution B.

The coating solution obtained by mixing 50 parts of the above dispersion A and 100 parts of the dispersion B was coated on a 49 g/rd high-quality paper using a wire bar so that the dry weight was 8 g/n (dry weight). A thermosensitive recording medium was obtained.

Example 2 In the preparation of Solution B of Example 1, N,N',N" instead of N,N'-diphenylbenzamidine.

A thermosensitive recording material was obtained in the same manner as in Example 1 except that N'''-tetraphenylhexanecyamidine was used.

Example 3 B of Example 1: 1.2. in place of N,N'-diphenylbenzamidine in av74. A thermosensitive recording material was obtained in the same manner as in Example 1 except that a-nitriphenylguanidine was used and N-benzyl-p-)luenesulfonamide was used instead of methanesulfono-p-phenetidide.

Example 4 In the preparation of solution A of Example 1, 4-morpholino-2,5
A thermosensitive recording material was obtained in the same manner as in Example 1 except that p-N,N-dipropylaminobenzenediazonium phosphorus hexafluoride salt was used instead of dibutoxybenzenediazonium phosphorus hexafluoride salt.

Examples 5 to 6 In the preparation of Solution B of Example 1, N,N-diisobutyl-
p-Toluenesulfonamide, 1-chloro-N-(2-
A thermosensitive recording material was obtained in the same manner as in Example 1 except that (naphthyl)-ethanesulfonamide was used.

Comparative Example 1 A thermosensitive recording material was obtained in the same manner as in Example 1 except that methanesulfono-p-phenetidide was not blended in the preparation of liquid B in Example 1.

Comparative Examples 2 to 3 In the BfitJl product of Example 1, methanesulfono-
A thermosensitive recording material was obtained in the same manner as in Example 1 except that stearamide and di-4-methylphenyl carbonate were used in place of p-phenetidide.

Comparative tests were conducted on the recording sensitivity and storage stability of the nine types of heat-sensitive recording bodies thus obtained. In other words, regarding the recording sensitivity, thermal recording is performed using a Gull type practical facsimile (UF-2, manufactured by Hirodendensen), the image is fixed by exposure to ultraviolet light, and then the color density is measured using a Macbeth densitometer (yellow filter). It was measured with In addition, regarding the storage stability of the recording material, the thermal recording material immediately after coating and the
The capri densities of the recording layers of the thermosensitive recording bodies after being left for 24 hours under conditions of 0° C. and 90% RH were measured using a Macbeth densitometer (yellow filter) and compared.

The test results obtained are shown in Table 1.

Table 1 "Effects" As is clear from the results in Table 1, the heat-sensitive recording bodies obtained in each example of the present invention all have excellent recording sensitivity, and the storage of the recording bodies It had excellent stability.

Although the reason why such excellent effects are obtained is not necessarily clear, the present inventors estimate that the microcapsules containing the diazonium compound and the specific sulfonamide compound exhibit an excellent synergistic effect. ,
As a result, it is presumed that the storage stability and recording sensitivity of the recording medium can be significantly improved. That is, the above-mentioned specific sulfonamide compound not only lowers the melting point of coupler compounds and compounds that exhibit a basic atmosphere when heated (but also significantly improves the coupler compound permeability of the capsule wall membrane when heated, resulting in It is thought that this promotes the coupling reaction in the capsule and contributes to the improvement of recording sensitivity.

Claims (2)

[Claims] (1) In a photofixable thermosensitive recording material provided with a recording layer containing a microcapsule containing a diazonium compound, a coupler compound, and a compound that exhibits a basic atmosphere when melted, the recording layer further includes a melting point of 70 to 70. A heat-sensitive recording material containing a sulfonamide compound having a temperature of 180°C. (2) The heat-sensitive recording material according to claim (1), wherein the sulfonamide compound is a compound represented by the following general formula [I]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] [In the formula, R_1 and R_2 each represent a lower alkyl group; a cyclic alkyl group; an aryl group; an aralkyl group or a heterocyclic residue, and R_3 is a hydrogen atom or a lower Indicates an alkyl group. Note that the alkyl group contained in the formula may be substituted with a halogen atom, and the aromatic ring is a halogen atom, a lower alkyl group,
It may be substituted with a lower alkoxyl group, an acylamino group or an alkylamino group. ]