JPS6079994A - Thermal recording paper - Google Patents

Abstract

PURPOSE:To provide a thermal recording paper such that developed color images and ground color are resistant to hair treatment toiletries, oils and fats, wherein a specified metallic salt derivative of 2-subst. benzoic acid is incorporated in a color forming layer comprising a basic colorless dye and an organic developer. CONSTITUTION:In a thermal recording paper comprising a color forming layer comprising a basic colorless dye, e.g., 3-diethylamino-6-methyl-(p-chloroamino) fluoran, and an organic color developer, the color forming layer further comprises a metallic salt derivative of 2-subst. benzoic acid of the formula, wherein X is carbonyl, methylene, an ester group or -O-, each of R1-R5 is H, alkyl, alkoxy, nitro or halogen, and n is 2 or 3, preferably, a Zn, Ca or Mg salt of 2-(4- methylbenzoyl)benzoic acid, preferably in an amount of 1-8 parts per 1 part of the dye. The effect of the addition of the metallic salt derivative is particularly conspicuous when the color developer is a monophenolic 4-hydroxyphenyl compound or a phthalic acid monoester.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal recording paper whose colored image and ground color are stable against hair styling agents and oils and fats.

Thermal recording paper that utilizes a heat-based color-forming reaction between a so-called basic colorless dye, which is normally colorless or light-colored, and an organic color developer such as 7 enols or an organic acid is disclosed in Japanese Patent Publication No. 43-4160 and Japanese Patent Publication No. 45
-14039, JP-A No. 48-27736, etc. have been published and have been widely put into practical use. In general, thermal recording paper is produced by separately grinding and dispersing a basic colorless dye and an organic color developer into fine particles, and then mixing them together with binders, fillers, sensitivity enhancers, lubricants, and other auxiliaries. A coating liquid obtained by adding a dye is applied to a support such as paper or film, and a color record is obtained by an instantaneous chemical reaction caused by heating.In this case, a colorless dye type is selected. These thermal recording papers can be used in measurement recorders in the medical or industrial fields, computers and information communication terminals, facsimile machines, printers for electronic desk calculators, and automatic ticket vending machines. Applications are progressing in a wide range of fields, including machines.

By the way, thermal recording paper cannot avoid being touched by human hands due to its function as information recording paper, but the hands and fingers of the person handling it may be exposed to hair products used on a daily basis or oils and fats contained in the sweat of the skin. Since thermal recording paper is often contaminated with oily substances such as However, in general, thermal recording paper is not sufficiently stable against these oily substances, and the density of the colored image in the contaminated area may decrease or disappear, and the phenomenon of discoloration when the white background area becomes contaminated has also been observed. It will be done. The causes of these problems are not fully understood, but oily substances may partially dissolve the color-forming layer formed by fine particles of basic colorless dye and organic color developer or their color-forming reactants, or may cause unstable It is considered to be a condition.

The present invention provides a heat-sensitive recording paper that is stable against contamination by oily substances such as those described above. It is characterized by containing a 2-substituted benzoic acid metal salt derivative.

The general formula H represents an alkyl group, an alkyl group, an alkyl group, or a halogen group, M represents a polyvalent metal, and n represents an integer of 2 to 3. ) The present invention will be explained in detail below.

The organic color developer used in the present invention is not particularly limited, and any type of coloring agent may be used, but it does not meet the basic quality requirements of thermal recording paper, that is, high-density and clear recording. Mono, phenolic 4-hydroxyphenyl compounds, and heptalic acid have the advantage of being free from problems such as adhesion of lees and sticking to the saber head, excellent recording suitability, and little background color development over time. The effect of the present invention is most pronounced when a monoester is used as a color developer. Examples of monophenolic 4-hydroxyphenyl compounds include ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, and 4-hydroxybenzoate. Isoglobil hydroxybenzoate, butyl 4-hydroxybenzoate, inbutyl 4-hydroxybenzoate, benzyl 4-hydroxybenzoate, 4-reL, methylbenzyl 4-hydroxybenzoate, 4-hydroxybenzoate acid 4'-1
- 4-hydroxybenzoic acid esters such as butylbenzyl, 4-hydroxy7notal such as dimethyl 4-hydroxyphthalate, diisoglobil 4-hydroxy7talate, dibenzyl 4-hydroxy7talate, dihexyl 4-hydroxy7talate, etc. Acid diester, 4-hydroxyacetophenone, P-phenylphenol, benzyl-4-hydroxyfuuni/1fufucetate, P-
Pe/zylphenol, di-4-hydroxyphenyl-
4'-〇-Buteroxyphenylsulfone, 4-hydroxyphenyl-4/, -hexyloxyphenylsulfone, 4-hydroxyphenyl-4'-n-octyloxyphenylsulfone, 4-hydroxyphenyl-4'
-゛-Tesyloxyphenylsulfo, F, 4-hydroxyphenyl-4'-n-dodenyloxyquenylsulfone, 4'-hydroxyphenyl-4'-benzyloxyphenylsulfone, 4-hydroxyphenyl-4'- p
-'Isopropylbenzyloxyphenylsulfone, 4
-Hydroxyphenyl-4-β-phenethyloxyphenylsulfone, 4-hydroxyphenyl-41-β-ethoxyethyloxy7alesulfone, 4-hydroxy 7, Uniru-4'-β-butoxyethyloxyphenylsulfone, 4-hydroxy Phenyl-4'-β-7enoquine ethyloxyphenyl sulfone, 4-hydroxyphenyl-4'-0-chlorobenzoyloxyphenyl sulfone, 4-hydroxyphenyl-4'-β-1-￥f
Rubenzoyloxyphenylnulpho/, 4-hydroxyphenyl-4-β-electro-octerbe/zoyloxyphenylsulfone, 4-hydroxyphenyl-47-lauriloyloxyphenylsulfone, 4-hydroxyphenyl-4'-decanoyloxy sinoenylsulfo/, 4-
Hydroxyphenyl-4'-myristoyloxyphenylsulfone, 4-hydroxyphenyl-4'-stearyloxyphenylsulfone, 4-hydroxyphenyl-
4'-β-phenoxypropionyloxyphenylsulfone, 4-hydroxyphenyl-4'-hexadecylsulfonyloxophenylsulfone, 4-hydroxyphenyl-4'-7'silsulfonyloxyphenylsulfone, 4-hydroxyphenyl-4 '-p-)luenesulfonyloxyphenylsulfone, 4-hydroxyphenyl-4'-p-inglobilbenzenesulfonyloxyphenylsulfone, 4-human[1xyphenyl-4'
-'(4-p-+-butylphenoxyphthyloxy)phenylsulfone, 4-hydroxyphenyl-4'
-(4-p-+-amylphenoxybutyloxy)phenylsulfone, 4-hydroxyphenyl-4'-(5
-, p-electrobutylphenoxyamyloxy) phenylsulfone, 4-hydroxyphenyl-4'-(6-p-
Examples include 1-butylphenoxyhexyloxy) phenylsulfone.

On the other hand, mononisdel phthalates include mononoenyl phthalate, monobenzyl heptathalate, monocyclohexyl heptathalate, monomethylphenyl phthalate, monoethylphenyl hepthalate, monoalkylbenzyl heptalate ester. , heptatalic acid monohalogen benzyl ester, phthalic acid monoalkoxybenzyl ester, and the like.

Although these color developers are excellent in basic required quality, they have a drawback in that they are slightly less stable against oily substances than bisphenol compounds, which are generally used in conventional amounts.

In addition, as bisphenol compounds, 4.4'-ingropylidenediphenol (bisphenol), 4.4
'(1-methyl-n-hexylidene)dinenol, 4.4'-cyclohexylidene diphenol, 4.4
'-Thiobis (4-tert-butyl-3-methylphenol) can be exemplified, but these color developers also have low color-forming properties when combined with colorless dyes. υInsufficient stability against oily substances.

Regarding stability against oily substances, various dyes are commonly known as basic colorless dyes that are usually colorless or light in color and are used in the invention in combination with the 2-substituted benzoic acid metal salt derivative as a stabilizer according to the present invention. ,lr! It is not limited to f. For example, examples of fluoran-based colorless dyes include the following. 3-diethylamino-6-methyl-7-
Anilinofluoro/(black), 3-(N-ether-P-
toluidino)-6-methyl-7-anilinofluorane (black), 3-diethylamino-6-methyl-7-(ortho, para-dimethylanilino)fluoran (black),
3-pyrrolidino-6-methyl-7-anilinofluorane (black), 3-piveridino-6-methyl-7-anilinofluorane (black), 1-(N-cyclohexyl-
N-, )' thylamino)-6-methyl-7-anilithufluoro/(black), 3-diethylamino-7-(meta-trifluoromethylanilino)fluoro/(7, “
＾color), 3-diptylamino-7-(ortho-chloroanilino)fluoran (black), 3-diethylamino-6
-Methyl-chlorofluorane (“IF color”):”
l -3-cyclohexylamino-6-chlorofur 2nd
(orange).

In addition, among the fluoran-based black coloring dyes, 3-diethylamino-6-methyl-(bala-chloroanilino)fluora/, 3-diethylamino-7-(ortho-chloroanilino)fluoran%, 3-(N-ethyl-P-toluibino) )-6-Methyl-7-anilitufluora/,3-dibutylamino-6-methyl-(ortho-chloroanilino)
Fluoran, 3-(N-ethyl-isoamyl)amino-
6-Methyl-tuanilinofluorane and the like are considered to be dyes with rather low coloring properties, and the density of the colored image is slightly insufficient, but 2-@benzoin specified in the present invention during coloring 1- By adding the acid metal salt rust conductor tm, it is possible to not only improve the stability against oily substances but also improve the image quality.

Furthermore, regarding basic colorless dyes other than fluoran-based dyes,
It can be used in the present invention. That is, crystal
Violet lacto/, methyl violet lactone, 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindole-3-
yl) 4-aza7thalide, 3-(4-diethylamine-
2-Ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-7-aza 7-talide, etc. is a color developer for monophenolic 4-hydroxyphenyl compounds and 7-talic acid monoester. When used in combination with thermochromic paper, a thermochromic phenomenon in which the colored image disappears immediately after printing or gradually disappears, making it impossible to use it as thermal recording paper. By using the 2-substituted benzoic acid metal salt derivative as a stabilizer, the thermochromic phenomenon did not occur.

In the present invention, the 2-substituted benzoic acid metal salt derivative used as a stabilizer is represented by the general formula described above, and specific examples thereof include 2-(4-methylbenzoyl)benzoic acid, 2- (4-chlorobenzoyl)benzoic acid, 2-(3-
Chloro-4-methylbenzoyl)benzoic acid, 2-(4-
Chloro-3-nitrohensoyl)an, lika JL 2-
(4-Nitrobenzoyl)benzoic acid, 2-benzylbenzoic acid, 2-(4-methylbenzyl)benzoic acid, 2-(4
-chlorobenzyl)benzoic acid, 2-(3-chloro-4-
methylbenzyl)benzoic acid, 2-(4-chloro-3-nitrobenzyl)benzoic acid, phthalic acid mono/4-methulfenyl ester, phthalic acid mono-4-chlorophenyl ester 2-benzyloxybenzoic acid 111.2-( 4-nitrobenzyloxy)benzoic acid, 2-(4-methylphenoxy)benzoic acid 2-phenoxybenzoic acid, 2-(4--4
0 phenoxy)benzoic acid, etc. are shown,
Particularly suitable are metal salt derivatives of 2-(4-methylbenzoyl)benzoic acid. Further, as the metal, any polyvalent metal such as zinc, calcium, magnesium, barium, or lead may be used, but zinc, calcium, and magnesium are excellent. Two or more of these stabilizers can be used in combination, if necessary.

The aforementioned organic color developer and basic colorless dye and 2-11
The converted benzoic acid metal salt derivative is atomized to a particle size of several microns or less using a ball mill or a suitable emulsifying device, and various additive materials are added depending on the purpose to prepare a cram school liquid. This coating liquid contains polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, Tengun, styrene-maleic anhydride copolymer, vinyl acetate maleic anhydride copolymer, styrene-butadiene copolymer. Binding agents such as coalescing) 11
．． .

kaolin, calcined kaolin, diatomite, talc, e
Inorganic or organic fillers such as carbonate, calcium carbonate, magnesium carbonate, and aluminum hydroxide are added, but in addition, mold release agents such as fatty acid metal salts, lubricants such as waxes, and benzophenone and triazole-based fillers are added. Ultraviolet absorbers, water-resistant agents such as glyoxal, dispersants, antifoaming agents, etc. can be used. By applying this coating liquid to paper and various films, the desired heat-sensitive recording paper can be obtained.

The amount of 2-substituted benzoic acid metal salt derivative used in the present invention,
It is determined according to each ff + sweep of the 41 h, rc length 1 + fj, renal performance and recording suitability, and is usually determined according to the performance and recording suitability of the 41h. 3 to 10 parts of the agent, 1 to 8 parts of the 2-substituted benzoic acid metal salt derivative, and 1 to 20 parts of the filler, and the binder was 10 to 25 parts in the total solid content [Example 1] Solution A (dye dispersion) ) Solution B (yJR colorant dispersion) Solution C (stabilizer dispersion) Six solutions of the above compositions were ground to a particle size of 3 microns using a ball mill. Next, the dispersion liquid was mixed in the proportions shown in Table 1 to form a coating liquid. Coating liquid formulation of Example 1 Each of the above coating liquids was mixed at 509/n? Coating amount 6,0 on one side of the base paper
t/rr? The sheet was coated and dried to give a smoothness of 200 to 300 seconds using a supercalender. Shigeru 2 shows the results of a quality performance test performed on the obtained black-colored thermal recording paper.

Note (1) Color density 2 Tokyo Shibaura Electric thermal facsimile C
Using P6000, the solid black printed area was measured using a Macbeth densitometer (RD 104, using an amber filter. The same applies below) under Gll mode.

Note (2) Color density after oil treatment: After spreading a droplet of castor oil (0.8 mg) dropped onto a glass plate with a syringe to a size of 200 mm, use a 15 + x 1.5 m rubber stamp to apply the above ( 1) Transferred to the printed surface. After leaving for 7 days, the color density of the metastatic area was measured using a Maches densitometer.

Note (3) Remaining rate of color density: Calculated using the following formula.

Note (4) Measure the uncolored part of the ground color using a Macbeth densitometer.

Note (5) Ground color after oil treatment: Castor oil was transferred to the uncolored area in the same manner as in (2) above. After leaving for 3 days, the concentration of the metastatic area was measured using a Macbeth densitometer.

Note (6) Ground color after treatment at 60°C and 45% RH: Temperature 60
After being left for 24 hours under harsh conditions of ℃ and humidity 45SR),
Measure the uncolored area with a Macbeth densitometer.

As is clear from Table 2, the color images of the examples of the present invention using 2-substituted benzoic acid metal salts as stabilizers are stable even when contaminated with castor oil, and even after 7 days have passed since the contamination. 7
It has a color density residual rate of 0 or more. In addition, the stability of the ground color is good, and there is little deterioration in the ground color even with oil contamination or severe storage. In particular, among the stabilizers used in the present invention, those containing zinc as a metal salt have a high residual color density even when contaminated with oil.

[Example 2] In Solution B (developer dispersion) of Example 1, benzyl 4-hydroxybenzoate was replaced with the same weight part of monobenzyl phthalate, and Solutions A and C were prepared in the proportions shown in Table 3. and a calcium carbonate dispersion.

Table 3. Coating liquid formulation of Example 2 Table 4 shows the quality performance test results for a black-colored thermal recording paper obtained in the same manner as in Example 1 using the above-mentioned can liquid.

In Table 4, the effect of the stabilizer according to the example of the present invention is remarkable even when the color developer is monobenzyl 7-talate ester.

[Example 3] Solution A (dye dispersion) Solution B (developer dispersion) Solution C (stabilizer dispersion) The canned liquid of the above composition was ground with an attritor to a particle size of 3 microns. . Next, the dispersion liquid was mixed at the following ratio a to prepare a coating liquid.

Examples of the present invention Comparative examples (13 to 16') (27 to 30) Human fluid (dye dispersion) 6.8 parts 6.8 parts B solution (developer dispersion 0 525 parts 525 parts C solution (stabilizer dispersion) Liquid → 6
．． 0 parts - Calcum carbonate 50% dispersion' 20.0 parts 200 parts Table 5 shows the quality performance test results for black-colored thermal recording paper obtained in the same manner as in Example 1 using each of the above liquids. .

As is clear from Table 5, zinc 2-(4-methylbenzoyl)benzoate has an excellent effect on stabilizing colored images; When used as a coloring agent, its stabilizing effect is extremely remarkable.

Claims (4)

[Claims] (1) In a thermosensitive recording paper provided with a coloring layer containing a basic colorless dye and an organic color developer, the coloring layer may contain a 2-substituted benzoic acid metal salt derivative represented by the general formula below. Features thermal recording paper. 〇- or -〇-, R+-, R1, Rs, Ra and R. are H, an alkyl group, an alkoxy group, a nitro group. or represents a halogen group, M is a polyvalent metal, and n is 2 to 3
indicates an integer. ) (2) The above 2-substituted benzoic acid metal salt derivative is 2-(4-
The heat-sensitive recording paper according to claim 1, characterized in that it is a metal salt of methylbenzoylbenzoic acid. (3) Claim 1, characterized in that M in the above general formula is zinc, calcium or magnesium.
The thermal recording paper according to item 1 or 2. (4) The thermal recording paper according to claim 1.2 or 3, wherein the organic color developer is a monophenolic 4-hydroxyphenyl compound or a phthalic acid monoester.