JPH0624137A - Thermal recording material - Google Patents

Abstract

PURPOSE:To maintain color-developing sensitivity, and to improve oil resistance, plasticizer resistance and heat resistance by adding bis (benzoic acid ester) sulfone shown in specified general formula to the material of a recording layer composed of electron-donating colorless dyes, an acidic substance for rendering the dyes thermosensitive, and a binding agent. CONSTITUTION:Bis (benzoic acid ester) sulfone shown in formula is contained in a recording layer. Where R in formula represents 1-18C alkyl group or alkoxy group, an aralkyl group, which may have a substituent group, or a phenyl group, which may have the substituent group, and R1 and R2 may be the same or differ, and represent a hydrogen atom, 1-5C alkyl group or alkoxy group, a nitro group, a cyano group or a halogen atom. A bis (benzoic acid ester) sulfone compound may be compounded 0.5-10 times and a binding agent 0.3-3 times in total amount with a triallyl methane group compound (electron-donating colorless dyes) and a phenolic compound (an electron-accepting compound).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material having high sensitivity and improved light resistance, moisture resistance, particularly plasticizer resistance, oil resistance and heat resistance. It's about paper.

[0002]

2. Description of the Related Art The performance required for a recording layer of a thermosensitive recording paper is excellent in thermosensitive properties such as self-coloring resistance, pressure coloration resistance, light resistance, moisture erasing resistance, plasticizer resistance and water resistance. However, there is currently no product that completely satisfies them. On the other hand, speeding up recording due to social demand,
With the improvement of image storability, it is needless to say that not only the recording apparatus itself has been speeded up, but also the recording material is required to correspond to the speedup and have a stable image with less background fog.

Conventionally, in order to improve the color developing sensitivity, JP-A-59-30557, JP-A-60-82382, and JP-A-6-68382.
There are proposals to add a low melting point compound to the heat-sensitive recording layer, such as JP-A-3-126784 and JP-A-64-40373. On the other hand, in order to improve the image storability, JP-A-60- 79996, JP-A-61-26373.
92, JP-A-62-266292, JP-A-63-128.
978, JP-A-63-209885 and JP-A-2-1.
There is a description of adding compounds such as JP-A No. 365.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present inventors have used a known electron-donating colorless dye as a color-developing agent according to a conventionally known method and the method described in each of the above-mentioned patent publications to obtain a heat-sensitive recording. When paper was manufactured and tested for performance to be provided as a thermal recording paper, the color development was excellent, and the compound having excellent image stability had large background fog and background fog after the image storability test. The compound of which the heat-sensitive recording material had high sensitivity and had good background fog had insufficient image storability.

The present invention provides a heat-sensitive recording paper which retains color development sensitivity without soiling the background after the image storability test and improves image stability, particularly oil resistance, plasticizer resistance and heat resistance. It is a thing.

[0006]

The inventors of the present invention have completed the present invention as a result of earnest studies to improve the above-mentioned drawbacks with respect to a heat-sensitive recording material using a known electron-donating colorless dye. is there.

That is, in the present invention, a recording layer basically having a colorless or slightly light-colored electron-donating colorless dye, an acidic substance for coloring the electron-donating colorless dye under heat, and a binder is provided on a support. In the heat-sensitive recording paper provided in, the following general formula (1) in the recording layer,

[0008]

[Chemical 2]

(Wherein R is an alkyl group having 1 to 18 carbon atoms,
It represents an alkoxyalkyl group having 1 to 18 carbon atoms, an aralkyl group which may have a substituent and a phenyl group which may have a substituent. R ₁ and R ₂ may be the same or different, and are a hydrogen atom, an alkyl group having 1 to 5 carbon atoms,
As a substituent having an alkoxy group having 1 to 5 carbon atoms, a nitro group, a cyano group, or a halogen atom and having an aralkyl group and a phenyl group, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and a substituent having 1 to 5 carbon atoms Alkoxy group, nitro group,
It is a cyano group or a halogen atom. The present invention relates to a heat-sensitive recording material containing a bis (benzoic acid ester) sulfone represented by

Next, specific examples of the compound used in the present invention are shown in (Table 1) and (Table 2) below, but the present invention is not limited thereto.

[0011]

[Table 1]

[0012]

[Table 2]

As the electron-donating colorless dye used in the present invention, triallylmethane compounds, diphenylmethane compounds, xanthene compounds, thiazine compounds, oxazine compounds, spiropyran compounds, fluorene compounds, etc. are known. There is.

To give an example of some of these, as a triallylmethane compound, 3,3-bis (P-dimethylaminophenyl) -6-dimethylaminophthalide {CV
L}, 3,3-bis (P-dimethylaminophthalide),
3- (P-dimethylaminophenyl) -3- (1,3-
Dimethylindol-3-yl) phthalide, 3- (P-
Dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide and the like.

As the xanthene compound, rhodamine B
-Anilinolactam, rhodamine B (P-nitroanilino) lactam, rhodamine B (P-chloroanilino) lactam, 2-dibenzylamino-6-diethylaminofluorane, 2-anilino-6-diethylaminofluorane, 2-anilino-3 -Methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6- (N-cyclohexyl-N-methyl) aminofluorane, 2-o-
Chloroanilino-6-diethylaminofluorane, 2-
o-chloroanilino-6-dibutylaminofluorane,
2-p-chloroanilino-6-diethylaminofluorane, 2-octylamino-6-diethylaminofluorane, 2-p-acetylanilino-6-diethylaminofluorane, 2-ethoxyethylamino-3-chloro-6
-Diethylaminofluorane, 2-anilino-3-chloro-6-diethylaminofluorane, 2-diphenylamino-6-diethylaminofluorane, 2-anilino-
6- (N-ethyl-N-tolyl) aminofluorane, 2
-Anilino-3-methyl-6- (N-ethyl-N-tolyl) aminofluorane, 2-anilino-3-methyl-6
-(N-methyl-N-n-propyl) aminofluorane, 2-anilino-3-methoxy-6-dibutylaminofluorane, 2-anilino-3-methyl-6-n, ndibutylaminofluorane, 2 -Anilino-3-methyl-
6- (N-ethyl-N-tetrahydrofurfuryl) aminofluorane, 2-anilino-3-methyl-6- (N-
n-Butyl-N-tetrahydrofurfuryl) aminofluorane, 2-anilino-3-methyl-6- (N-ethyl-
N-i-amyl) aminofluorane, 2-anilino-3
-Methyl-6- (N-ethyl-N-sec.butyl) aminofluorane, 2-chloro-3-methyl-6-p (p
-Phenylaminophenyl) aminoanilinofluorane, 2-p-phenylureidoanilino-6-N-cyclohexyl-N-methylaminofluorane and the like.

As the fluorene compound, 3 ', 6'
Bisdiethylamino-5-diethylaminospiro (isobenzofuran-1,9-fluorene) -3'-one,
3 ', 6' Bisdiethylamino-5-dibutylaminospiro (isobenzofuran-1,9-fluorene) -3 '
-There is an on.

As the pentadiene compound, 1- (α
-Methoxy (4-N, N-dimethylamino) benzyl)
-3- (4-N, N-dimethylaminobenzylidene)-
5-methyl-cyclohexene and the like.

Examples of thiazine compounds include benzoylleuco methylene blue and p-nitrobenzoylleucomethylene blue.

Examples of oxazine compounds include 3,7-bis (diethylamino) -10-benzoyl-phenoxazine and 3,7-bis (diethylamino) -10-acetylphenoxazine.

Examples of spiro compounds include 3-methylspirodinaphthopyran, 3-benzylspiro-dinaphthopyran, 3-propylspiro-dibenzopyran and the like. These are used alone or as a mixture, but the present invention is
It is not limited to these electron-donating colorless dyes.

The electron-accepting compound (developing agent) used in the present invention is preferably a phenolic compound, an organic acid or a metal salt thereof, hydroxybenzoic acid ester and the like, and specific examples include the following. To be

Salicylic acid, 3-isopropylsalicylic acid, 3,5-di-tert. -Butylsalicylic acid, 3,
5-di-α-methylbenzyl salicylic acid, 4,4′-isopropylidene diphenol, 4,4′-isopropylidene bis (2-chlorophenol), 4,4′-isopropylidene bis (2,6-dichlorophenol) ), 4,
4'-isopropylidene bis (2,6-dimethylphenol), 4,4'-isopropylidene bis (2-ter)
t. -Butylphenol), 4,4'-cyclohexylidenebisphenol, 4,4'-cyclohexylidenebis (2-methylphenol), 4-tert. -Butylphenol, 4-phenylphenol, 4-hydroxydiphenoxide, α-naphthol, β-naphthol,
3,5-xylenol, thymol, methyl-bis (4-
Hydroxyphenyl) acetate, n-butyl-bis (4-hydroxyphenyl) acetate, 4,4'-thiodiphenol, bis (4-hydroxy-3-methylphenyl) sulfide, 4,4'-diphenolsulfone, 4 -Isopropoxy-4'-hydroxydiphenyl sulfone, 1,7-di (4-hydroxyphenylthio)
-3,5-dioxaheptane, phloroglysin carboxylic acid, 4-tert. -Octylcatechol, 2,2'-
Methylenebis (4-chlorophenol), 2,2'-methylenebis (4-methyl-6-tert.-butylphenol), 2,2'-dihydroxydiphenyl, ethyl p-hydroxybenzoate, propyl p-hydroxybenzoate, p -Butyl hydroxybenzoate, benzyl p-hydroxybenzoate, p-chlorobenzyl p-hydroxybenzoate, o-chlorobenzyl p-hydroxybenzoate, p-methylbenzyl p-hydroxybenzoate,
p-Hydroxybenzoic acid-n-octyl, benzoic acid, zinc salicylate, 1-hydroxy-2-naphthoic acid, 2-
Hydroxy-6-naphthoic acid, zinc 2-hydroxy-6-naphthoate, 4-hydroxydiphenyl sulfone, 4
-Hydroxy-4'-chlorodiphenyl sulfone, 2-
Hydroxy-p-toluic acid, 3,5-tert. -Zinc butylsalicylate, 3,5-tert. -Tin butylsalicylate, tartaric acid, oxalic acid, maleic acid, citric acid,
Examples include succinic acid, stearic acid, 4-hydroxyphthalic acid, boric acid, thiourea derivatives and 4-hydroxythiophenol derivatives.

A water-soluble or water-insoluble binder is used as the binder for binding the mixture of the color former and the developer onto the support sheet. Typical examples are polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, gum arabic, starch, gelatin, casein, polyvinylpyrrolidone, styrene-maleic anhydride copolymer, polyacrylic acid amide, and polyacrylic acid salt. , And terpene resin and petroleum resin, the binder which can be particularly preferably used in the present invention is a water-soluble binder, and a typical one thereof is polyvinyl alcohol.

The weight ratio of each of the above-mentioned components and the binder in the recording layer when the thermal recording paper is manufactured is
The total amount of the bis (benzoic acid ester) sulfone compound represented by the general formula (1) is 0.5 to 10 times that of the color former.
It is preferably 2 to 4 times, and the binder is 0.3 to 3 times, preferably 0.5 to 2 times.

The color-developing agent and the color-developing agent are separately dispersed by using a dispersing machine such as a ball mill, a dyno mill, a sand mill or a paint conditioner, and the bis (benzoic acid ester) sulfone represented by the general formula (1) is dispersed. The compound having may be dispersed alone or with a color former or with a developer, and is dispersed in water containing a binder or in an organic medium, preferably water in which the binder is dissolved. And pulverize to form a suspension having a particle size of 0.5 to 6 μ, preferably 0.5 to 2 μ. If necessary, an antifoaming agent, a dispersant, a whitening agent, or the like may be added to disperse and be pulverized.

Next, a coating material for forming a thermosensitive recording layer by separately dispersing each of the above-mentioned components and mixing the pulverized suspensions of the components as described above in the weight ratio of each component in the recording layer. And Apply this paint to the surface of the paper with a wire bar No. 6-No. 20 is applied so that the weight of the solid matter after drying is 3 to 10 g / m ² , and dried in a blow dryer at room temperature to 70 ° C. to produce a thermal recording paper. If necessary, an inorganic or organic filler may be added to the coating material in order to improve the fusion resistance of the thermal head, the writability and the like.

[0027]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 Liquid A (Dye Dispersion Liquid) 2-anilino-3-methyl-6-dibutylaminofluorane 8 parts Amide stearate 4 10% Polyvinyl alcohol 40 Water 28 Liquid B (developer dispersion liquid) 4 , 4 isopropylidene diphenol (abbreviated as BPA) 4 parts Zinc stearate 3 compound No. 1 4 10% Polyvinyl alcohol 10 Water 59 C liquid (filler dispersion liquid) 30% Calcium carbonate D liquid (binder liquid) 10% Polyvinyl alcohol

A and B in each liquid of the above composition are pulverized with a Dyno-Mill KDL disperser to a particle size of 0.5 to 2 μm. Next, the respective liquids are mixed in the following proportions to prepare a coating material for thermal recording paper. Liquid A 4 parts B 16 C 10 D 4 This mixed paint was applied to the surface of fine paper No. Using a wire bar of 18, the solid content after drying was applied so as to be 7 g / m ^2, and the solid content was put into a blower drier and dried to obtain a thermosensitive recording paper.

Example 2 Compound No. 1 according to the present invention in solution B. 1 to compound No. Two
A liquid E dispersion liquid was obtained in the same manner as the liquid B preparation except that

Next, the respective liquids are mixed in the following proportions to prepare a coating material for thermal recording paper. Liquid A 4 parts E 16 C 10 D 4 The following coating materials were used in the same manner as in Example 1 to obtain a thermosensitive recording paper.

Example 3 Compound No. 1 to compound No. A liquid F dispersion was obtained in the same manner as the liquid B preparation except that the liquid B was changed to 3.

Next, the liquids are mixed in the following proportions to prepare a coating material for thermal recording paper. Liquid A 4 parts F 16 C 10 D 4 The following coating materials were used in the same manner as in Example 1 to obtain a thermosensitive recording paper.

Example 4 Compound No. 1 to compound No. Except for changing to 4, liquid G liquid dispersion was obtained in the same manner as liquid B preparation. Next, the respective liquids are mixed in the following proportions to prepare a coating material for thermal recording paper. Liquid A 4 parts G 16 C 10 D 4 The following coating materials were used in the same manner as in Example 1 to obtain a thermosensitive recording paper.

Example 5 Compound No. 1 to compound No. Except for changing to 5, liquid H liquid dispersion was obtained in the same manner as liquid B preparation. Next, the respective liquids are mixed in the following proportions to prepare a coating material for thermal recording paper. Liquid A 4 parts H 16 C 10 D 4 The following coating materials were used, and the same procedure as in Example 1 was carried out to obtain a thermosensitive recording paper.

Example 6 Compound No. 1 to compound No. A liquid H liquid dispersion was obtained in exactly the same manner as the liquid B preparation, except that the solution 6 was used. Next, the respective liquids are mixed in the following proportions to prepare a coating material for thermal recording paper. Liquid A 4 parts H 16 C 10 D 4 The following coating materials were used, and the same procedure as in Example 1 was carried out to obtain a thermosensitive recording paper.

Example 7 A liquid P liquid dispersion was obtained in exactly the same manner as the liquid B of the first embodiment except that the composition was changed to the following. Liquid P (developer dispersion liquid) Methyl-bis (4-hydroxyphenyl) acetate 4 parts (abbreviated as MBA) Zinc stearate 3 Compound No. 1 4 10% Polyvinyl alcohol 10 Water 59 Next, the respective liquids are mixed in the following proportions to prepare a coating material for thermal recording paper. Liquid A 4 parts P 16 C 10 D 4 The following coating materials were used in the same manner as in Example 1 to obtain a thermosensitive recording paper.

Example 8 Compound No. 1 to compound No. A liquid Q liquid dispersion was obtained in the same manner as the liquid P preparation except that the solution 2 was used. Next, the respective liquids are mixed in the following proportions to prepare a coating material for thermal recording paper. Liquid A 4 parts Q 16 C 10 D 4 The following coating materials were used in the same manner as in Example 1 to obtain a thermosensitive recording paper.

Example 9 Compound No. 1 to compound No. Except for changing to 3, liquid R dispersion liquid was obtained in the same manner as liquid P preparation. Next, the respective liquids are mixed in the following proportions to prepare a coating material for thermal recording paper. Liquid A 4 parts R 16 C 10 D 4 The following coating materials were used in the same manner as in Example 1 to obtain a thermosensitive recording paper.

Control Example 1 Compound No. Except that 1 was changed to water, the same procedure as in the preparation of solution B was carried out to obtain a dispersion of solution S. Next, the respective liquids are mixed in the following proportions to prepare a coating material for thermal recording paper. Liquid A 4 parts S 16 C 10 D 4 The following coating materials were used in the same manner as in Example 1 to obtain a thermosensitive recording paper.

Control Example 2 Compound No. A T liquid dispersion was obtained in exactly the same manner as the B liquid preparation except that 1 was changed to parabenzyl biphenyl. Next, the respective liquids are mixed in the following proportions to prepare a coating material for thermal recording paper. Liquid A 4 parts T 16 C 10 D 4 The following coating materials were used in the same manner as in Example 1 to obtain a thermosensitive recording paper.

Control Example 3 Compound No. Except for changing 1 to benzyloxynaphthalene, the same procedure as for preparation of solution B was carried out to obtain a solution U. Next, the respective liquids are mixed in the following proportions to prepare a coating material for thermal recording paper. Liquid A 4 parts U 16 C 10 D 4 The following coating materials were used in the same manner as in Example 1 to obtain a thermosensitive recording paper.

Control Example 4 Compound No. 1 was changed to 1,1,3 tris (2-methyl-4-hydroxy-5-tert.-butylphenyl) butane, and the procedure was the same as for preparation of solution B.
A liquid dispersion was obtained. Next, the respective liquids are mixed in the following proportions to prepare a coating material for thermal recording paper. Liquid A 4 parts W 16 C 10 D 4 The following coating materials were used in the same manner as in Example 1 to obtain a thermosensitive recording paper.

Examples 1 to 9, Control Examples 1 to 4
Each of the thermal recording papers obtained in step 1 was cut into a predetermined paper having a width of 20 cm and calendered with a lily roll mini calender so that the smoothness was 300 seconds.
A performance test was conducted.

The results are shown in the columns of Examples and Controls in (Table 3).

[0046]

[Table 3]

Note 1: Color development density-color development energy curve in which the color development density is plotted on the vertical axis and the color development energy is plotted on the horizontal axis, using a dynamic color tester manufactured by Matsushita Electronic Parts Co., Ltd., 10 to 75 mm. The thermosensitive recording paper was colored under the coloring conditions of Joule and load of 1.5 kg / cm ² . The color-developed portion was measured with a Macbeth reflection densitometer RD-918, the color-developing energy showing a reflection density of 1.0 was defined as J1.0, and the energy (mj) at this time was designated as the color-developing sensitivity.

Note-2: The uncolored portion under the conditions of Note-1 above was designated as the background D ₀ .

Note-3: A 5% castor oil-chloroform solution was applied onto polyester using a film applicator, air-dried, and then castor oil on the film was 1.5 cm × 1.
cm is stamped on the part of J1.0 which is colored under the condition of Note 1 above, the color density D ₁ after treatment at 60 ° C. and relative humidity 90% for 3 hours is measured, and the color development residual rate = (D ₁ /1.0)*100 was obtained and this was taken as the oil resistance. The uncolored portion under the above conditions was designated as background D ₂ .

Note-4: Uniformly cover the J1.0 portion developed with Saran Wrap (manufactured by Asahi Kasei) under the conditions of Note-1 above 5
A load of 0 g / cm ² was applied at 0 ° C., and the color density D ₃ after the treatment for 24 hours was measured to obtain a color development residual rate = (D ₃ /1.0)*100, which was taken as the plasticizer resistance. . The uncolored portion under the above conditions was designated as background D ₄ .

[0051]

As is apparent from (Table 3), the heat-sensitive recording material of the present invention has a conventionally known sensitizer or preservative improving agent such as parabenzyl biphenyl, benzyloxynaphthalene and 1,1,3 tris (2). -Methyl-4-hydroxy-5-tert.-butylphenyl) butane has better background fog and color development sensitivity than thermal recording papers, especially oil resistance, plasticizer resistance and heat resistance during storage. The property was remarkably improved.

Claims (1)

[Claims] 1. A recording layer, which basically comprises a colorless or slightly light-colored electron-donating colorless dye, an acidic substance that develops the color of the electron-donating colorless dye when heated, and a binder, is provided on a support. In the thermosensitive recording paper, the following formula (1), (In the formula, R is an alkyl group having 1 to 18 carbon atoms, and 1 to 1 carbon atoms
8 represents an alkoxyalkyl group of 8, an aralkyl group which may have a substituent and a phenyl group which may have a substituent. R ₁ and R ₂ may be the same or different and each is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or 1 to 5 carbon atoms.
5 represents an alkoxy group, a nitro group, a cyano group or a halogen atom. And a bis (benzoic acid ester) sulfone represented by the formula (1).