JPH04267188A - Development sheet for pressure sensitive recording - Google Patents

Abstract

PURPOSE:To improve color development properties such as developed color density and development rate in color development for pressure sensitive record ing by adding the metal salt of salicylate derivative expressed by a specific chemical formula and the multivalent metal salt complex of thiocyanic acid to a single layer. CONSTITUTION:The metal salt of salicylate derivative expressed by a specific chemical formula and the multivalent metal salt complex of thiocyanic acid is added to a single layer of a pressure sensitive recording material. In the formula, a group expressed by R1 to R4 is hydrogen atom, an alkyl group or an aryl group. The recommended salicylate derivative is 3,5-bisaralkylsalicylio acid, 3-aralkylsalicylic acid, 3-alkyl-5-aralkysalicylic acid or 3-alkyl-5-alkylsalicylic acid. In addition, the preferably recommended salicylate derivative should have a total carbon number of 17 or higher. Further, the recommended metal salt of salicylate derivative is zinc salt and the recommended multivalent metal salt complex of thiocyanic acid is a zinc complex of thiocyanic acid.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to pressure-sensitive recording materials, and more particularly to color-developing sheets for pressure-sensitive recording that have improved durability over time.

0002

2. Description of the Related Art Recording materials using electron-donating colorless dyes and electron-accepting compounds are already well known. For example, UK patent 2140449, US patent 4480052,
4436920, JP-A-62-144,989, etc. for details. As a pressure-sensitive recording material, research has been conducted in recent years to improve properties such as (1) color density and color development speed, (2) fastness of the color body, and (3) improved durability under various usage conditions. The present inventors have investigated the oil solubility, water solubility, partition coefficient, pKa, polarity of the substituent, position of the substituent, and compatibility with each of the electron-donating colorless dye, electron-accepting compound, and additive. We have pursued the development of good materials for recording materials and recording materials, focusing on characteristics such as changes in crystallinity and solubility.

0003

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a color developing sheet for pressure-sensitive recording which has good color development density and color development speed and satisfies other requirements.

0004

[Means for Solving the Problems] An object of the present invention is to prepare a complex of an electron-donating colorless dye, a metal salt of a salicylic acid derivative represented by the following general formula (I), and a polyvalent metal salt of thiocyanate. This problem was solved by a color developing sheet for pressure-sensitive recording, which is characterized by containing salt in the same layer. General formula (I)

[0005]

[Case 2]

In the formula, R1, R2, R3 and R4
The group represented by represents a hydrogen atom, an alkyl group or an aryl group.

In the above general formula (I), R1, R2, R3
The groups represented by You can leave it there. These substituents may further have a substituent. R1
, R2, R3 and R4 include a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and a carbon atom atom. An alkoxy group having 1 to 20 carbon atoms is preferred, and R1 and R3 are particularly preferably a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms.

Among the salicylic acid derivatives represented by the above general formula (I), 3,5-bisaralkylsalicylic acid derivatives, 3-alkylsalicylic acid, 3-alkyl-5-aralkylsalicylic acid, or 3-alkyl-5-alkylsalicylic acid is preferable, and those having a total carbon number of 17 or more are preferable.

Preferred metal salts of salicylic acid derivatives according to the present invention include zinc salts, aluminum salts, magnesium salts, calcium salts, sodium salts, and nickel salts, with zinc salts being particularly preferred.

The present invention is not limited to these specific examples of salicylic acid derivatives according to the present invention. 3,
5-bis(-α-methylbenzyl)salicylic acid, 3-α
-Benzylated phenylethylsalicylic acid, 3-α-methyl-α-ethylpentyl-5-α,α-dimethylbenzylsalicylic acid, 3-cumyl-5-t-octylsalicylic acid, 3-cumyl-5-t-butylsalicylic acid , 3-t-
Butyl-5-cumylsalicylic acid, 3,5-di-t-butylsalicylic acid, 3,5-di-t-octylsalicylic acid,
3,5-di-t-nonylsalicylic acid, 3,5-bis(methylcumyl)salicylic acid, 3,5-biscumylsalicylic acid, 3-α-methylbenzyl-6-methylsalicylic acid, 3-α-benzylated phenylethyl-6 -Methylsalicylic acid, 3-α-methyl-α-ethylpentyl-6-
Methyl salicylic acid, 3,5-bis(-α-benzylated phenylethyl) salicylic acid, 3,5-bis(benzylated benzyl) salicylic acid, 3,5-bis(α-methylbenzyl)-6-methylsalicylic acid, 3-α -Tolylethyl-6-methylsalicylic acid, 3,5-bis(α,α-dimethylbenzyl)-6-methylsalicylic acid, 3,5-di-
t-Octyl-6-methylsalicylic acid, 3-α-dimethylphenylethyl-6-methylsalicylic acid, 3-α-ethylphenylethyl-6-methylsalicylic acid, 3-α-
isopropylphenylethyl-6-methylsalicylic acid,
3-α-benzylated benzylphenylethyl-6-methylsalicylic acid, 3-α-methyl-α-ethylpentyl-
Examples include 6-ethylsalicylic acid.

Among the complexes of polyvalent metal thiocyanate according to the present invention, those represented by the following general formula (II) are preferred. General formula (II) (L)m Me(SCN)n In the above general formula (II), L is M via a hetero atom.
A monodentate or polydentate organic ligand that combines with e to form a complex, Me is an n-valent metal atom, n is 2 or 3, m
represents a number from 1 to 3.

Among the metal atoms represented by Me in the above general formula (II), aluminum, barium, calcium,
Magnesium or zinc is preferred, and zinc is particularly preferred. Among the organic ligands represented by L in the above general formula (II), antipyrine, pyridine, imidazole, imidazoline, 3-pyrazolone, 5-pyrazolone, benzothiazole, quinoline, guanidine, etc. are preferable, and these ligands are It may further have a substituent.

The polyvalent metal thiocyanate complex according to the present invention is preferably liquid at room temperature or has a melting point of 200°C or less.

Next, typical examples of the complex of polyvalent metal thiocyanate according to the present invention will be shown. Zinc thiocyanate imidazole complex, zinc thiocyanate 2-methylimidazole complex, zinc thiocyanate 2-dodecylimidazole complex, zinc thiocyanate 3-decylimidazole complex,
Zinc thiocyanate 3-octadecyl imidazole complex,
Examples include, but are not limited to, zinc thiocyanate antipyrine complex, zinc thiocyanate 3-benzylimidazole complex, zinc thiocyanate triphenylguanidine complex, and the like.

The color developing sheet for pressure-sensitive recording according to the present invention further uses well-known compounds other than the present invention, such as phenol derivatives, salicylic acid derivatives, metal salts of aromatic carboxylic acids, acid clay, bentonite, and novolak. Resins, metal-treated novolak resins, metal complexes, etc. may be used in combination. Examples of these are Special Publication No. 9309 of 1972 and Special Publication No. of 1973.
-14039, JP 52-140483, JP 48-51510, JP 57-210886, JP 58-87089, JP 59-11286,
JP 60-176795, JP 61-95988
It is stated in the number etc.

Pressure-sensitive recording materials using the color developing sheet according to the present invention are disclosed in US Pat. No. 2,505,470, US Pat.
No. 505,471, No. 2,505,489, No. 2,5
No. 48,366, No. 2,712,507, No. 2,73
No. 0,456, No. 2,730,457, No. 3,103
, No. 404, No. 3,418,250, No. 4,010,
It can take a variety of forms as described in prior patents such as No. 038. Most commonly it consists of at least one pair of sheets containing separately an electron-donating colorless dye and an electron-accepting compound.

Electron-donating colorless dyes include triphenylmethane phthalide compounds, fluoran compounds, phenothiazine compounds, indolylphthalide compounds, leukoolamine compounds, rhodamine lactam compounds, and triphenylmethane compounds. , triazene compounds, spiropyran compounds, and fluorene compounds. Specific examples of phthalides are U.S. Reissue Patent Specification No. 23,024 and U.S. Patent Specification No. 3,491,111.
No. 3,491,112, No. 3,491,11
6 and US Pat. No. 3,509,174, and specific examples of fluorans are US Pat. No. 3,462,828, No. 3,681,390,
No. 3,920,510, No. 3,959,571, and specific examples of spirodipyrans are given in U.S. Patent Specification No. 3,9.
No. 71,808; pyridine and pyrazine compounds are described in U.S. Patent No. 3,775,424;
Specific examples of fluorene compounds are described in Japanese Patent Application No. 53,869, No. 4,246,318, and Japanese Patent Application No. 61-240989.

In the color developing sheet for pressure-sensitive recording according to the present invention, the electron-accepting compound is an electron-donating colorless dye of 50 to 5
000% by weight, more preferably 100 to 2000% by weight.

[0019] Methods for producing capsules include a method using coacervation of a hydrophilic colloid sol described in US Pat. No. 2,800,457 and US Pat. 950,44
No. 3, No. 989,264, No. 1,091,076, etc., or the interfacial polymerization method described in US Pat. No. 3,103.
, No. 404, etc. Generally, electron-donating colorless dyes are used alone or in combination, and a solvent (synthetic oil such as alkylated naphthalene, alkylated diphenyl, alkylated diphenylmethane, alkylated terphenyl, chlorinated paraffin, etc.), cotton oil, castor oil, etc. A coloring agent sheet can be created by dissolving it in vegetable oil, animal oil, mineral oil, or a mixture thereof, incorporating it into microcapsules, and applying it to paper, high-quality paper, plastic sheet, resin-coated paper, etc. get the money.

On the other hand, the electron-accepting compound is prepared by mixing the polyvalent metal salt thiocyanate complex according to the present invention with additives as required, and placing it in a binder such as styrene-butadiene latex or polyvinyl alcohol. A developer sheet is formed by dispersing it and applying it together with a pigment to a support such as paper, plastic sheet, resin-coated paper, or the like. The amount of the polyvalent metal thiocyanate complex used in the present invention is 5 to 200% by weight, particularly 10 to 15% by weight of the salicylic acid derivative represented by the general formula (I) of the present invention.
0% by weight is used.

[0021] A method for mixing a general electron-accepting compound and a complex of a polyvalent metal thiocyanate according to the present invention is to dissolve the two using an organic solvent and then mix them, or to emulsify or solidly disperse the two separately. It may be mixed afterwards. This is emulsified with a water-soluble polymer such as polyvinyl alcohol, and the organic solvent used here is preferably removed under normal pressure or reduced pressure after emulsification. The organic solvent used is preferably a halogenated hydrocarbon, aromatic hydrocarbon, ester, ketone, ether, amide, or nitrile having a boiling point of 200 degrees or less. Among these, those having a solubility in water at room temperature of 5 or less are preferred. Specific examples of organic solvents include chloroform, methylchloroform, benzene, toluene, xylene, chlorobenzene, ethyl acetate, butyl acetate, isopropyl acetate, methyl ethyl ketone, methyl isobutyl ketone, dimethylacetamide, and the like.

Examples of water-soluble polymers include polyvinyl alcohol, maleic anhydride-isobutylene copolymer, carboxymethyl cellulose, hydroxyethyl cellulose, polyacrylamide, polyacrylic acid, acrylamide-alkyl acrylate copolymer, ether-modified polyvinyl alcohol, and cyanoethyl. Synthetic or natural polymers such as modified polyvinyl alcohol, polyvinylpyrrolidone, starch, casein, gum arabic, and gelatin can be used. Examples of pigments include zinc oxide, aluminum hydroxide, calcium carbonate, titanium oxide, magnesium carbonate, magnesium oxide, barium sulfate, kaolin, activated clay, and talc. Of these, the average particle size is 5.
Calcium carbonate of 0 μ or less, 60% by weight of the total pigment
It is particularly preferable to use the above. If the amount of calcium carbonate used is less than 60% by weight, sufficient performance in terms of light resistance of the color former and yellowing of the color developing surface due to light cannot be obtained. Further, unless calcium carbonate with an average particle size of 5.0 μm or less is used, sufficient color developing ability cannot be obtained. Average particle size5.
Calcium carbonate with a particle size of 0 μ or less is commercially available, such as Shiroishi Kogyo's Brilliant-15 and Brilli.
ant-S15, Brilliant-30, PC, P
Examples include CX and Unibur-70. The electron-accepting compound and the pigment are preferably used in a weight ratio of 1:5 to 1:15. If the ratio of pigment used is higher or lower than this, sufficient color developing ability cannot be obtained. Further, a part of the electron-accepting compound may be used in a dispersion liquid that is mechanically dispersed in an aqueous system using a ball mill, an attritor, a sand mill, etc., together with a dispersant, a water-soluble polymer, and other additives. Examples of additives that may be added to the electron-accepting compound as needed include antioxidants, radiation absorbers, and the like.

The amount of the electron-accepting compound applied to the support is suitably 0.1 g/m2 to 2.0 g/m2, preferably 0.2 g/m2 to 1.0 g/m2. The amount of the electron-donating colorless dye to be used depends on the desired coating thickness, the form of the pressure-sensitive recording paper, the capsule manufacturing method, and other conditions, and may be appropriately selected depending on the conditions. It is easy for one skilled in the art to determine this amount to use.

[0024]

[Examples] Examples are shown below, but the present invention is not limited thereto. Unless otherwise specified in the examples, weight % is expressed.

Example-1 1) Preparation of capsule sheet containing electron-donating colorless dye 5 parts of a partial sodium salt of polyvinylbenzenesulfonic acid (manufactured by National Starch Co., Ltd., VERSA, TL500) was dissolved in 95 parts of hot water. Cool afterwards. A sodium hydroxide aqueous solution was added to this to adjust the pH to 4.0. On the other hand, the electron-donating colorless dye 3-(2-ethoxy-4-diethylaminophenyl)-3-(1-octyl-2-methylindole-
100 parts of diisopropylnaphthalene in which 4.5% of 3-yl)phthalide was dissolved was emulsified and dispersed in 100 parts of a 5% aqueous solution of a partial sodium salt of the polyvinylbenzenesulfonic acid to obtain an emulsion having a particle size of 4.0 μm in diameter. Obtained. Separately 6 parts of melamine. 37% by weight formaldehyde aqueous solution 1
Part 1. 30 parts of water was heated and stirred at 60°C, and after 30 minutes, a transparent aqueous solution of melamine formaldehyde prepolymer was obtained. This aqueous solution was mixed with the above emulsion. Adjust the pH to 6.0 with 2M phosphoric acid solution while stirring, and bring the temperature to 65°.
The temperature was raised to C and stirring was continued for 6 hours. This capsule liquid was cooled to room temperature and adjusted to pH 9.0 with an aqueous sodium hydroxide solution. 10% by weight of polyvinyl alcohol based on this dispersion.
200 parts of starch particles and 50 parts of starch particles were added;
Water was added to prepare a solution of microcapsule dispersion with a solid content concentration of 20%. Apply 5g of this coating liquid to 50g/m2 base paper.
The mixture was coated using an air knife coater so that a solid content of /m2 was coated, and dried to obtain a capsule sheet containing an electron-donating colorless dye.

2) Preparation of electron-accepting compound sheet [Preparation of pigment dispersion] Calcium carbonate (Shiraishi Kogyo Brilli)
Using 120 parts of ant-15 (average particle size: 0.5μ), 10 parts of activated clay, 20 parts of zinc oxide, 1 part of sodium hexametaphosphate, and 200 parts of water, use a sand grinder to uniformly grind the particles to an average particle size of 3μ. Disperse to form a pigment dispersion liquid (A
) was obtained. [Preparation of electron-accepting compound emulsion] 3,5-bis(-α
-20 parts of zinc (methylbenzyl) salicylate and 5 parts of the complex of polyvalent metal thiocyanate according to the present invention shown in Table 1 were mixed with 18 parts of toluene, and 100 parts of a 10% PVA-117 (manufactured by Kuraray) aqueous solution was added. Emulsify for 5 minutes using a homogenizer (Nippon Seiki, Au-7 type) to reduce the average particle size to 1.
．． An emulsion (B) of an electron-accepting compound having a particle size of 0 μ was obtained. 300 parts of pigment dispersion (A) and 1 part of electron-accepting compound emulsion (B)
To 05 parts, 85 parts of a 10% PVA-117 aqueous solution was added, and further water was added so that the solid content concentration was 20% to obtain a coating liquid. Apply this coating liquid to 50g/m2 of base paper at a rate of 5.1
Bar coating was applied so that a solid content of g/m2 was applied and dried to obtain an electron-accepting compound sheet.

[0027] The electron-donating colorless dye-containing microcapsule sheet surface was stacked on the electron-accepting compound sheet and 300 kg
Color was developed at room temperature (25°C) under a load of /cm2. The color density after 15 seconds was measured using a densitometer (Macbeth RD-514 model). The results are shown in Table 2.

Comparative Example An electron-accepting compound sheet was obtained in the same manner as in the example except that the compounds other than the present invention shown in Table 1 were used in place of the polyvalent metal thiocyanate complex according to the present invention. Color was developed in the same manner as in Example 1, and the color density was measured after 15 seconds. The results are shown in Table 2. [Aging resistance test] The surface of the electron-donating colorless dye-containing microcapsule sheet was superimposed on the electron-accepting compound sheet, and N was printed using a typewriter. A soft polyvinyl chloride sheet (0.5 mm thick, containing 15% by weight of dibutyl phthalate and 7% by weight of dioctyl phthalate as plasticizers) was placed on top of the obtained image, and 100g of it was placed in an atmosphere at 50°C and 20% humidity. /cm2 and left for 30 days. After 30 days, the images were visually observed for blurring and fading. The results are shown in Table 2.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Effects of the Invention] As shown in Table 2, it can be seen that the pressure-sensitive recording material using the color developing sheet according to the present invention has excellent color density and also has excellent durability over time.

Claims

[Claims] 1. A color developing sheet for pressure-sensitive recording, comprising a metal salt of a salicylic acid derivative represented by the following general formula (I) and a complex of a polyvalent metal salt of thiocyanate in the same layer. General formula (I) embedded image In the formula, the groups represented by R1, R2, R3 and R4 represent a hydrogen atom, an alkyl group or an aryl group.
2. The salicylic acid derivative according to claim 1, wherein the salicylic acid derivative is 3,5-bisaralkylsalicylic acid, 3-alkylsalicylic acid, 3-alkyl-5-aralkylsalicylic acid, or 3-alkyl-5-alkylsalicylic acid. Color developer sheet for pressure-sensitive recording. 3. The color developing sheet for pressure-sensitive recording according to claim 1, wherein the complex of polyvalent metal thiocyanate is a zinc thiocyanate complex.