JPH06104786B2 - Developer, its dispersion and developer sheet - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a color developer, a dispersion thereof and a color developing sheet. More specifically, the present invention relates to a color developing agent comprising a polyvalent metal salt of a salicylic acid derivative, which is suitable as a color developing agent for pressure-sensitive recording paper, a dispersion thereof and a color developing sheet using the same.

[0002]

2. Description of the Related Art Conventionally, a nucleus-substituted salicylic acid polyvalent metal salt, particularly a zinc salt thereof, has been known as an organic developer for pressure-sensitive recording paper. For example, a polyvalent metal salt of a salicylic acid derivative disubstituted with α-methylbenzyl group, α, α-dimethylbenzyl group, cyclohexyl group and the like at the 3- and 5-positions of salicylic acid (Japanese Patent Publication No. 51-25174) is known. Has been. JP 62
JP-A-84045 discloses a mixture of [(α-methylbenzyl) -α'-methylbenzyl] salicylic acid polyvalent metal salt and 3,5-di (α-methylbenzyl) salicylic acid polyvalent metal salt. Also has two styrene units, and the mixing ratio thereof is 50:50 (weight ratio). Further, JP-A-2-91043 discloses that a salicylic acid derivative having two styrene units and a salicylic acid derivative having three styrene units are mixed at a mixing ratio of 72:28 or 85: 1.
A mixture containing 5 parts is disclosed.

[0003]

However, the color developer comprising such a salicylic acid derivative polyvalent metal salt has a drawback of yellowing due to nitrogen oxide gas. Further, it is also insufficient in terms of color development speed and saturated color development density.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies as a solution to the above-mentioned problems, and as a result, a color developing agent which has less yellowing due to nitrogen oxide gas and has improved coloring speed and saturated coloring density. The inventors have found the dispersion and the color developing sheet, and arrived at the present invention.

That is, the present invention comprises a polyvalent metal salt of a salicylic acid derivative, wherein the salicylic acid derivative is (a) 5-60 with respect to the total of (a), (b) and (c) below.
%, (B) 15 to 70% by weight, (c) 10 to 40% by weight; a developer obtained by dispersing the above developer in water in the presence of a dispersant; and the above developer. A color-developing sheet in which a layer containing a colorant is formed on the sheet. (A) 1 mol of salicylic acid is reacted with 1 mol of salicylic acid derivative (b) 1 mol of salicylic acid is reacted with styrene, 2 mol of salicylic acid derivative is reacted (c) 1 mol of salicylic acid is reacted with 3 mol of styrene Reacted salicylic acid derivative

The present invention will be described in more detail. Examples of the salicylic acid derivative (a) in the present invention include 3- (α
-Methylbenzyl) salicylic acid, 5- (α-methylbenzyl) salicylic acid, 3- (α, α-dimethylbenzyl) salicylic acid, 5- (α, α-dimethylbenzyl) salicylic acid, 3
-(4'-Methyl-α-methylbenzyl) salicylic acid, 5- (4'-methyl-α-methylbenzyl) salicylic acid, 3- (3'-methyl-α
-Methylbenzyl) salicylic acid, 5- (3'-methyl-α-methylbenzyl) salicylic acid, 3- (4'-hydroxy-α-methylbenzyl) salicylic acid, 5- (4'-hydroxy-α-methylbenzyl) salicylic acid , 3- (4'-chloro-α-methylbenzyl) salicylic acid, 5- (4'-bromo-α-methylbenzyl)
Such as salicylic acid.

The salicylic acid derivative (b) is, for example,
3,5-di (α-methylbenzyl) salicylic acid, 3,5-di (α, α-dimethylbenzyl) salicylic acid, 3,5-di (4'-
Methyl-α-methylbenzyl) salicylic acid, 3,5-di (3'-
Methyl-α-methylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5- (α, α-dimethylbenzyl) salicylic acid, 5- [4 '-(α'-methylbenzyl) -α-methylbenzyl] salicylic acid , 3- [4 '-(α'-methylbenzyl) -α
-Methylbenzyl] salicylic acid, 3- (1 ', 3'-diphenylbutyl) salicylic acid, 5- (1', 3'-diphenylbutyl) salicylic acid and the like.

The salicylic acid derivative (c) is, for example,
3- (α-methylbenzyl) -5- [4 '-(α'-methylbenzyl) -α-methylbenzyl] salicylic acid, 3- [4'-(α'-
Methylbenzyl) -α-methylbenzyl] -5- (α-methylbenzyl) salicylic acid, 3- (4'-methyl-α-methylbenzyl) -5- [4 '-(α'-methylbenzyl) -α- Methylbenzyl] salicylic acid, 3- (α, α-dimethylbenzyl) -5-
[4 '-(α'-Methylbenzyl) -α-methylbenzyl] salicylic acid, 3- [4'-(α'-methylbenzyl) -α-methylbenzyl] -5- (α-methylbenzyl) salicylic acid, 3 -
(Α-Methylbenzyl) -5- (1 ', 3'-diphenylbutyl) salicylic acid, 3- (1', 3'-diphenylbutyl) -5-
(Α-methylbenzyl) salicylic acid and the like.

The salicylic acid derivative in the present invention is
(A) 5 to 60 for the total of (a), (b), and (c)
% By weight, preferably 10-45% by weight (b) 15-70% by weight,
It preferably comprises 30 to 60% by weight, (c) 10 to 40% by weight, preferably 12 to 30% by weight. When (a) is less than 5% by weight, yellowing due to nitrogen oxide gas is large or the saturated color density is low. If it exceeds 60% by weight, the color development speed is lowered and the saturated color density is also lowered. (B) is 15
If it is less than 10% by weight, depending on the ratio of (a) and (c), the coloring speed is low, or the saturated coloring density is low,
Or, yellowing due to nitric oxide gas becomes large, and either one is unsatisfactory. If it exceeds 70% by weight, yellowing due to nitric oxide gas is large. When (c) is less than 10% by weight,
Yellowing due to nitric oxide gas is large, or color development speed is low. If it exceeds 40% by weight, the saturated color density will be low.

The metal constituting the polyvalent metal salt of the salicylic acid derivative in the present invention is a divalent, trivalent or tetravalent metal such as zinc, calcium, magnesium, barium, lead, aluminum, zirconium, vanadium and tin. Can be given. Preferred of these is zinc,
High color density.

Salicylic acids in the present invention include salicylic acid, 3-ethylsalicylic acid, 5-ethylsalicylic acid,
Alkyl-substituted salicylic acids such as 3-tert-butylsalicylic acid; alicyclic group-containing salicylic acids such as 5-cyclohexylsalicylic acid; halogen-containing salicylic acids such as 5-chlorosalicylic acid; and mixtures thereof. Of these, preferred is salicylic acid, which has high color development speed and color density.

Examples of styrenes include styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, p-chlorostyrene, 2,4-dimethylstyrene, p-vinylphenol and vinylnaphthalene. Can be given. You may use 2 or more types together. Of these, preferred is styrene, which reacts with salicylic acid at low temperatures and is low in impurities.

The color developer of the present invention is usually prepared by mixing the salicylic acid derivatives (a), (b) and (c) alone in a desired ratio, or by mixing salicylic acid and styrene. It can be obtained by reacting in a desired ratio in the presence of a specific catalyst. Preferred is a method with less manufacturing complexity.

In the method (1), the salicylic acid derivatives (a), (b) and (c) are individually prepared by reacting phenols and styrenes by a known method, and after fractionating each precursor by distillation under reduced pressure. It can be obtained by the method described in JP-B-51-21174, in which CO2 is reacted under pressure. Also, a salicylic acid derivative alone can be obtained by reacting salicylic acid and styrene in the presence of an acidic catalyst and separating the reaction product by preparative column chromatography.

In the method (1), a polyvalent metal salt of an organic carboxylic acid is preferable as a catalyst for reacting salicylic acids with styrenes. The salicylic acid derivative (a), (b) of the present invention, which is not colored even when a SUS reaction tank is used,
The mixture of (c) can be produced, and the complexity of having to decolorize by filtration or chemical methods can be eliminated. Examples of the organic carboxylic acid include aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, palmitic acid, stearic acid, and oxalic acid; benzoic acid, salicylic acid, 3-benzylsalicylic acid, 5-benzylsalicylic acid, 3- (α-methylbenzyl). ) Salicylic acid, 5- (α-methylbenzyl) salicylic acid, 3- (α, α-dimethylbenzyl) salicylic acid, 5-
(Α, α-Dimethylbenzyl) salicylic acid, 3- (4'-hydroxy-α-methylbenzyl) salicylic acid, 5- (4'-hydroxy-α-methylbenzyl) salicylic acid, 3- (4'-chloro-α- Methylbenzyl) salicylic acid, 5- (4'-bromo-α
-Methylbenzyl) salicylic acid, 3,5-di (α-methylbenzyl) salicylic acid, 3,5-di (α, α-dimethylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5- (α, α
-Dimethylbenzyl) salicylic acid, 3,5-dibenzylsalicylic acid, 3-benzyl-5- (α, α-dimethylbenzyl) salicylic acid, 3-benzyl-5- (α-methylbenzyl) salicylic acid, 5- [4'- (Α'-Methylbenzyl) -α-methylbenzyl] salicylic acid, 3- [4 '-(α'-methylbenzyl) -α
-Methylbenzyl] salicylic acid, 3- (α-methylbenzyl) -5- [4 '-(α'-methylbenzyl) -α-methylbenzyl] salicylic acid, 3- [4'-(α'-methylbenzyl)- α
-Methylbenzyl] -5- (α-methylbenzyl) salicylic acid, 3- (α, α-dimethylbenzyl) -5-[-4 '-(α'-
Methylbenzyl) -α-methylbenzyl] salicylic acid, 3-
[4 '-(α'-Methylbenzyl) -α-methylbenzyl] -5-
(Α-methylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5- (1 ′, 3′-diphenylbutyl) salicylic acid,
Aromatic carboxylic acids such as 3- (1 ', 3'-diphenylbutyl) -5- (α-methylbenzyl) salicylic acid, 3,5-di (tert-butyl) salicylic acid and 3,5-dicyclohexylsalicylic acid . The latter aromatic carboxylic acid also includes a salicylic acid derivative obtained by the production method of the present invention. Of these, preferred are aromatic carboxylic acids.

The metal constituting the polyvalent metal salt of an organic carboxylic acid may be the same as the metal constituting the salicylic acid polyvalent metal salt, and zinc is preferable. The polyvalent metal salt of an organic carboxylic acid is added in an amount of 1 to 100 parts by weight, preferably 5 to 60 parts by weight, based on 100 parts by weight of salicylic acids.
When a polyvalent metal salt of an aromatic carboxylic acid is used, it can remain in the reaction product and contribute as a developer component.

As the catalyst, in addition to the polyvalent metal salt of organic carboxylic acid, a conventionally known acidic catalyst may be used in combination, if necessary. For example, alkyl sulfonic acids such as methyl sulfonic acid, ethyl sulfonic acid, propyl sulfonic acid; acrylamido-2-methylpropane sulfonic acid, vinyl sulfonic acid.
Vinyl (alkenyl) sulfonic acids such as nyl sulfonic acid; aromatic sulfonic acids such as p-toluene sulfonic acid, benzene sulfonic acid, xylene sulfonic acid; mineral acids such as hydrochloric acid, sulfuric acid, phosphoric acid; zinc carbonate, zinc chloride, aluminum chloride , Boron trifluoride, Friedel-Crafts catalyst such as activated clay. The amount of this acidic catalyst used is usually 10% by weight based on the polyvalent metal salt of organic carboxylic acid.
It is the following.

The reaction between salicylic acid and styrene is carried out at 80 to 180 ° C., preferably 100 to 150 ° C., by mixing both in the presence of the polyvalent metal salt of the organic carboxylic acid. The amount of styrene used is usually at least 1.0 mol or more, preferably 1.5 to 3.0, with respect to 1 mol of salicylic acid.
It is a mole. When used as a developer at least or at least, the color density is lowered. The reaction time varies depending on the reaction temperature, but is usually 30 minutes to 10 hours, preferably 1 to 5 hours.

The reaction between salicylic acid and styrene is carried out by mixing salicylic acid and a polyvalent metal salt of an organic carboxylic acid and heating and melting them, and then adding styrene, or a part of styrene, and salicylic acid and organic compound. After mixing the polyvalent metal salt of carvone, heating and melting, the method of adding styrenes, salicylic acids, styrenes once mixed,
There is a method of heating in the presence of a polyvalent metal salt of organic carvone while adding the mixture to a reaction tank. Preferred is
, Is the method.

If necessary, a suitable organic solvent can be used in the above reaction. Examples of the organic solvent include aliphatic hydrocarbon solvents such as pentane, hexane and cyclohexane; aromatic hydrocarbon solvents such as toluene, benzene and xylene; chlorinated hydrocarbon solvents such as ethylene dichloride, tetrachloroethylene and methylene chloride; acetone and methyl ethyl ketone. Ketones; esters such as acetic acid ester and propionic acid ester. The amount of the organic solvent added is usually 50% by weight or less based on the salicylic acid.

Regarding the method for producing the salicylic acid derivative,
A specific example will be described below. A mixture of salicylic acid and a polyvalent metal salt of an organic carboxylic acid is heated to 100 to 150 ° C. under stirring to form a fluid liquid. If necessary, part of styrene and / or the above organic solvent is added.
Furthermore, styrenes are added little by little over 30 minutes to 5 hours. After the addition, the salicylic acid derivative is obtained by further maintaining the temperature at 120 to 150 ° C. until the styrenes are exhausted to complete the reaction. It usually takes 0.5 to 2 hours.

The polyvalent metal salt of the salicylic acid derivative of the present invention is obtained by treating the salicylic acid derivative with the polyvalent metal compound (A) in the presence of an organic solvent or water, if necessary, at a temperature of usually 50 to 180 ° C. It is obtained by mixing and reacting. The polyvalent metal salt of the salicylic acid derivative is obtained by obtaining an alkali metal salt (sodium salt, potassium salt, etc.) or ammonium salt of the salicylic acid derivative, and then adding an inorganic acid polyvalent metal salt such as water or methanol or ethanol. It can also be produced by reacting in an aqueous solvent.

Examples of the polyvalent metal compound (A) include oxides, carbonates and hydroxides of the above-mentioned polyvalent metals, specifically, zinc oxide, zinc chloride, zinc sulfate, zinc carbonate, Zinc hydroxide, aluminum sulfate, nickel sulfate, tin chloride and zirconium oxychloride. For the purpose of promoting the reaction between the salicylic acid derivative and the polyvalent metal compound (A), ammonium carbonate, ammonium bicarbonate,
Ammonium salts such as ammonium acetate, ammonium formate, ammonium benzoate and ammonia may be added.

The organic solvent used as necessary includes aliphatic hydrocarbon solvents such as pentane, hexane and cyclohexane, aromatic hydrocarbon solvents such as toluene, benzene and xylene, chlorinated hydrocarbons such as ethylene dichloride, tetrachloroethylene and methylene chloride. Examples thereof include solvents, ketones such as methyl ethyl ketone and acetone, esters such as acetic acid ester and propionic acid ester, and alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol. One or more of these can be used. Preferred are toluene, methyl ethyl ketone, acetone, ethyl acetate, methyl alcohol and ethyl alcohol. The addition amount is usually 60% by weight or less based on the salicylic acid derivative.

The amount of the polyvalent metal compound (A) used is usually 0.5 to 2 equivalents, preferably 0.8 to 1 equivalent, per equivalent of salicylic acid.
1.2 equivalents. The reaction time depends on the melting temperature, the type of polyvalent metal compound (A), the amount used, the presence or absence of an organic solvent, and the type, but it is usually 1 to 5 hours.

The color developer of the present invention comprises a polyalkylene glycol-based (polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetramethylene glycol) block copolymer containing two or more of these in a molecular skeleton as a sensitizer. Or a random copolymer), and an ester system (a compound in which one end or both ends of the above polyalkylene glycol is blocked with an alkyl group having 1 to 6 carbon atoms or an acyl group having 6 to 23 carbon atoms). You can Among these, preferred are block or random copolymers containing polytetramethylene glycol and polytetramethylene ether skeleton, and acyl group-capped polyoxyalkylene. Particularly preferred are lauric acid diesters and oleic acid diesters of polytetramethylene glycol and polyethylene glycol, which significantly improve the coloring speed and the saturated coloring density.

The number average molecular weight of the above polyalkylene glycol sensitizer is 500 to 30,000, preferably 600 to 4000. When the number average molecular weight is less than 500, the color developing rate of the color developer decreases, and when it exceeds 30,000, the compatibility with the polyvalent metal salt deteriorates. The number average molecular weight of the above ester sensitizer is usually 100 to 10,000, preferably 150 to 4,000. If the number average molecular weight is less than 100, the color developing speed of the color developer decreases,
If it exceeds 000, the compatibility with the polyvalent metal salt is deteriorated.

The amount of the sensitizer contained in the developer of the present invention is usually 1 based on the weight of the polyvalent metal salt of salicylic acid derivative.
-30% by weight, preferably 2-20% by weight. If the sensitizer is less than 1% by weight, the effect of increasing the color development rate is poor, and if it exceeds 30% by weight, the color density is reduced.

The color developer of the present invention may contain, if necessary, auxiliary agents such as known color developers, binders, pigments, defoaming agents and thickeners. The concentration of the salicylic acid derivative polyvalent metal salt in the coating layer on the color developing sheet is usually 3 to 30% by weight.
Is.

Known developers include, for example, activated clay,
Inorganic solid acid such as bentonite; Phenolic condensate such as substituted phenol-formaldehyde resin and bisphenol A-formaldehyde resin and aliphatic such as zinc 3,5-di-t-butylsalicylate and zinc 3,5-di-cyclohexylsalicylate Group-substituted zinc salicylate and the like.

As the binder, starch and its derivatives, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose,
Cellulose derivatives such as ethyl cellulose; carboxyl group-containing (co) polymers such as sodium polyacrylate, saponified styrene / maleic anhydride copolymer, saponified isobutylene / maleic anhydride copolymer; acrylic acid amide / acrylic Acid ester copolymer, acrylic acid amide / acrylic acid ester / methacrylic acid terpolymer, acrylic acid amide such as polyacrylamide (co)
Polymers; Other water-soluble polymers such as polyvinyl alcohol, polyvinylpyrrolidone, sodium alginate, gelatin and casein, and styrene (co) polymers such as styrene / butadiene copolymers and styrene / butadiene / acrylic copolymers; polyacetic acid Vinyl, vinyl chloride (co) polymers such as vinyl chloride / vinyl acetate copolymer and ethylene / vinyl acetate copolymer; and latexes such as polyurethane, polyacrylic acid ester and polybutyl methacrylate. The amount of the binder used is usually 5 to 40% by weight, preferably 10 to 30% by weight, based on the total solid content of the developer coating solution.

As the pigment, kaolin, clay, talc, calcium carbonate, titanium oxide, silica, zinc oxide,
Examples thereof include inorganic pigments such as aluminum hydroxide and barium sulfate, and organic fine powders such as urea-formalin resin and polystyrene. The amount of the pigment used is usually 40 to 95% by weight based on the total solid content of the coating liquid.

The developer of the present invention may be used by dissolving it in an organic solvent such as toluene, methyl ethyl ketone and ethyl acetate, but it is usually used by dispersing it in water.

The aqueous dispersion of the color developer is usually 2 μm or less, preferably 1.5 μm or less, in the presence of the dispersant, the polyvalent metal salt of the salicylic acid derivative in water by a pulverizer such as a ball mill, an attritor or a sand grinder. It can be obtained by pulverizing and dispersing into particles of μ or less.

Further, the salicylic acid derivative is once made into an aqueous solution of an alkali metal salt or an ammonium salt, a dispersant is added to this, and an aqueous solution containing a polyvalent metal salt of an inorganic acid such as zinc sulfate and zinc chloride is further added. A color developer dispersed in water can also be obtained by adding an aqueous solution of the salicylic acid derivative salt containing the water-soluble polymer and the surfactant to the above under forced stirring with a homomixer or the like.

Further, the polyvalent metal salt of the salicylic acid derivative is dissolved in an organic solvent such as toluene, methyl ethyl ketone, ethyl acetate or ethylene dichloride, and if necessary, methyl alcohol, ethyl alcohol, acetone,
A water-soluble solvent such as dioxane is added to the above solution, and in the presence of a dispersant, a homomixer, a high pressure homogenizer, and the like are forcibly stirred, and after being atomized to about 0.2 to 2 μm, the organic solvent is distilled off. The developer of the present invention dispersed in desired water can be obtained.

Examples of such dispersants include alkali metal salts of sulfonated polystyrenes, styrene sulfonate (co) polymers, polyvinyl alcohol, naphthalene sulfonate / formalin condensate, and styrene-maleic anhydride copolymer. Saponified polymer, polyacrylic acid salt, acrylamide copolymer, hydroxyalkyl (meth) acrylic acid ester copolymer, hydroxyethyl (meth)
Polymeric dispersants such as acrylate (co) polymer, hydroxymethyl cellulose, hydroxypyropyr cellulose, oxidized starch, sodium alginate, etc., and dodecylbenzene sulfonate, dioctyl sulfosuccinate, sulfate ester of nonylphenol ethylene oxide adduct, etc. And nonionic surfactants such as nonylphenol, octylphenol, higher alcohols and ethylene oxide adducts of fatty acids. Considering the fact that there are few bubbles during dispersion and it is possible to easily make fine particles, polystyrene, styrene-maleic anhydride copolymer, styrene-acrylic acid copolymer, styrene- (meth) acrylic acid ester copolymer are preferable. It is a salt of a sulfonated polymer selected from coalescing. Particularly preferred is an alkali metal salt, alkaline earth metal salt, or ammonium salt of sulfonated polystyrene having a degree of sulfonation of 40 to 70 mol%. The amount of the dispersant used is usually 0.05 to 15% by weight, preferably 0.5 to 10% by weight, based on the polyvalent metal salt of the salicylic acid derivative.

The color developing sheet of the present invention comprises the color developing agent of the present invention,
It can be obtained by applying a dispersion or an organic solvent solution containing the above additives, if necessary, on a sheet-shaped support and drying. The method for forming the coating layer on the sheet of the developer coating solution is not particularly limited, and a conventionally known technique can be used. For example, by an air knife coater, a blade coater, a roll coater or the like, the above coating liquid is applied to the support, and usually 20 to
A coating layer is formed by drying at 120 ° C. The coating amount on the support is not particularly limited, but is usually 0.5 to 20 g / m ² as dry solid content, preferably
It is ² to 10 g / m ² . Examples of the support include paper, synthetic paper, synthetic resin film and the like, and particularly preferred is paper.

[0039]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto. Parts and% in the examples are by weight. The test methods used in the examples are shown below.

(Test Method) (1) Coloring of Polyvalent Metal Salt of Salicylic Acid Derivative The degree of coloring of the product was determined by the Gardner value in a 65% toluene solution. The larger the value, the larger the coloring.

(2) Composition of Salicylic Acid Derivative The weight ratio of the composition of the salicylic acid derivative in the present invention is the high performance liquid chromatography (column: Shim-
pack PREP-ODS (H) KIT). Detection condition UV: 240
nm

(3) Average Particle Diameter of Dispersant Containing Developer: The average particle diameter of the dispersion of the polyvalent metal salt of salicylic acid derivative is LA-700, a laser diffraction / scattering particle size distribution analyzer (manufactured by Horiba Ltd.). It was measured at. Usually, the smaller the particle size,
When used as pressure-sensitive paper, it shows good color density.

(4) NOx yellowing A developer sheet coated with a coating solution containing a developer was used as JI
According to S L0855, exposure to nitric oxide gas was performed, and the degree of yellowing of the coated surface was indicated by Hunter whiteness. The larger the value, the less the yellowing of the surface.

(5) Color development speed and saturated color density It was measured in a constant temperature and constant humidity of 20 ° C. and 65% RH. A commercially available blue-colored top paper having crystal violet lactone as a color-forming dye is used, and the coated surface and the color-developing sheet (bottom leaf paper) coated with the coating liquid containing the color-developing agent are opposed to each other.
After passing through the roll calender, the color densities after 15 seconds, 60 seconds and 1 hour were measured with a Macbeth densitometer. 1
The color density after the lapse of time hardly changed even after 24 hours, so the saturated color density was used. The higher the value, the higher the color density.

(6) Whiteness of developer sheet The Hunter whiteness of the sheet surface coated with the coating solution containing the developer is measured with a multi-source spectrophotometer (model MSC-2) manufactured by Suga Test Instruments Co., Ltd. did. The larger the number, the whiter the surface.

Example 1 In a 1 L container made of SUS equipped with a stirrer, 138 salicylic acid was added.
Parts, 5.5 parts of zinc acetate and 52 parts of styrene were added and heated to 155 ° C. with stirring and mixing. The mixture exotherms and melts. Next, 156 parts of styrene was added dropwise at a temperature of 145 ° C. over 2 hours. A light yellowish brown, transparent liquid substance was obtained. further,
Maintained at 145 ° C for 1 hour. The residual styrene in the reaction product is
It was 0.1% or less. By analyzing the components contained in the liquid material by liquid chromatography, 5- (α-methylbenzyl) salicylic acid, 3- (α) corresponding to the component (a) in the present invention is analyzed.
-Methylbenzyl) salicylic acid; 3,5-di (α-methylbenzyl) salicylic acid corresponding to the component (b) in the present invention; 3- (α corresponding to the component (c) in the present invention
-Methylbenzyl) -5- (1 ', 3'-diphenylbutyl)
Salicylic acid, 3- (1 ', 3'-diphenylbutyl) -5- (α
-Methylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5- [4 '-(α'-methylbenzyl) -α-methyl-benzyl] salicylic acid, 3- [4'-(α-methylbenzyl)- α-
It was a salicylic acid derivative mixture containing methylbenzyl] -5-α-methylbenzylsalicylic acid. (A),
The weight ratio of (b) and (c) was 38:40:22. Next, 205 parts of toluene and 48 parts of basic zinc carbonate (zinc content 58%) were added to the liquid material, and the mixture was stirred under reflux for 2 hours to give a toluene solution of a zinc salt of a salicylic acid derivative of the present invention having a solid content of 65%. Got

Example 2 In a 1 L container made of SUS equipped with a stirrer, 138 salicylic acid was added.
Parts, 50 parts of a toluene solution of the zinc salt of the salicylic acid derivative of the present invention prepared in Example 1, and 52 parts of styrene,
Heat to 145 ° C with stirring and mixing to melt. Next, 156 parts of styrene was added dropwise at a temperature of 145 ° C. over 2 hours.
A light yellowish brown, transparent liquid substance was obtained. Furthermore, at 145 ° C, 1
Maintained for hours. The residual styrene content in the reaction product was 0.1% or less. When measured by liquid chromatography, 5- (α-methylbenzyl) salicylic acid, 3- (α-methylbenzyl) salicylic acid corresponding to the component (a) in the present invention; 3,5 corresponding to the component (b) in the present invention -Ji (α-
Methylbenzyl) salicylic acid; 3- (α-methylbenzyl) -5- (1 ′, 3′-, which corresponds to the component (c) in the present invention.
Diphenylbutyl) salicylic acid, 3- (1 ', 3'-diphenylbutyl) -5- (α-methylbenzyl) salicylic acid, 3-
(Α-Methylbenzyl) -5- [4 '-(α'-methylbenzyl) -α-methylbenzyl] salicylic acid, 3- [4'-(α'-
It was a salicylic acid derivative mixture containing (methylbenzyl) -α-methylbenzyl] -5- (α-methylbenzyl) salicylic acid. The weight ratio of (a), (b), and (c) was 27:46:27. Next, 205 parts of toluene and 53 parts of basic zinc carbonate (zinc content 58%) are added, and the mixture is stirred under reflux for 2 hours so as to be uniform, and a toluene solution of a zinc salt of the salicylic acid derivative of the present invention having a solid content of 65%. Got

Example 3 In a 1 L container made of SUS equipped with a stirrer, salicylic acid 138 was added.
Part, 3,5-di (α-methylbenzyl) salicylic acid zinc salt 30
Parts and 52 parts of styrene were added and heated to 145 ° C. with stirring and mixing. The mixture exotherms and melts. Then styrene
208 parts was added dropwise at a temperature of 145 ° C. over 2 hours. A light yellowish brown, transparent liquid substance was obtained. Further, it was maintained at 145 ° C. for 1 hour. The residual styrene content in the reaction product was 0.1% or less. When measured by liquid chromatography, 5- (α-methylbenzyl) salicylic acid, 3- (α-methylbenzyl) salicylic acid corresponding to the component (a) in the present invention; 3,5 corresponding to the component (b) in the present invention -Di (α-methylbenzyl) salicylic acid; 3- (α-methylbenzyl) -5- (1 ′, 3′-diphenylbutyl) salicylic acid, 3- (1 ′, 3) corresponding to the component (c) in the present invention '-Diphenylbutyl) -5- (α-methylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5- [4'-(α'-methylbenzyl) -α-
It was a mixture of salicylic acid derivatives containing methylbenzyl] salicylic acid and 3- [4 ′-(α′-methylbenzyl) -α-methylbenzyl] -5- (α-methylbenzyl) salicylic acid as main components. The weight ratio of (a), (b), and (c) is
It was 11:58:31. Next, 53 parts of toluene and basic zinc carbonate (zinc content 58%) are added, and the mixture is stirred under reflux for 2 hours so as to be uniform, to give a toluene solution of the zinc salt composition of salicylic acid derivative of the present invention having a solid content of 65%. Obtained.

Example 4 138 salicylic acid was placed in a 1 L container made of SUS equipped with a stirrer.
Parts, a toluene solution of the zinc salt of the salicylic acid derivative of the present invention prepared in Example 1, 50 parts, methylsulfonic acid 0.5
Parts and 52 parts of styrene are added and heated to 145 ° C while stirring and mixing to melt. Next, 156 parts of styrene, temperature 145 ℃
Then, it was added dropwise over 1 hour. A light yellowish brown transparent liquid material was obtained. Further, it was maintained at 145 ° C. for 1 hour. The residual styrene content in the reaction product was 0.1% or less. When measured by liquid chromatography, 5- (α-methylbenzyl) salicylic acid, 3- (α-methylbenzyl) salicylic acid corresponding to the component (a) in the present invention; 3,5 corresponding to the component (b) in the present invention -Di (α-methylbenzyl) salicylic acid;
3- (α-methylbenzyl) -5- (1 ′, 3′-diphenylbutyl) salicylic acid, 3- (1 ′, 3′-diphenylbutyl) -5- (α corresponding to the component (c) in the present invention -Methylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5-
Contains [4 '-(α'-methylbenzyl) -α-methylbenzyl] salicylic acid, 3- [4'-(α'-methylbenzyl) -α-methylbenzyl] -5- (α-methylbenzyl) salicylic acid It was a salicylic acid derivative mixture. (A),
The weight ratio of (b) and (c) was 27:42:31. Then, 205 parts of toluene and 53 parts of basic zinc carbonate (zinc content 58%) are added, and the mixture is stirred under reflux for 2 hours so as to be uniform, and a toluene solution of a zinc salt of the salicylic acid derivative of the present invention having a solid content of 65%. Got

Comparative Examples 1 and 2 The procedure of Example 1 was repeated except that sulfuric acid (Comparative Example 1) or p-toluenesulfonic acid (Comparative Example 2) was used in place of the zinc acetate of Example 1. , A salicylic acid derivative was prepared. This salicylic acid derivative was treated in the same manner as in Example 1 to obtain a toluene solution of its zinc salt. There was a gray-black precipitate in the solution.

The Gardner values of the toluene solutions of the zinc salts of salicylic acid derivatives of Examples 1 to 4 and Comparative Examples 1 and 2 are shown in Table 1 below.

[0052]

[Table 1]

Examples 5 to 8 and Comparative Examples 3 to 4 Using the toluene solution of the zinc salt of salicylic acid derivative prepared in Examples 1 to 4 and Comparative Examples 1 and 2, the following method was used.
An aqueous dispersion of each salicylic acid derivative zinc salt was prepared.
To 100 parts of water, polyvinyl alcohol (Kuraray Poval P
VA205) 3.3 parts was dissolved. Rotate this aqueous solution at 1 rpm
100 parts of each of the toluene solutions of Examples 1 to 4 and Comparative Examples 1 and 2 were added while stirring with a homomixer (made by Tokushu Kiki) of 0000 rpm to obtain a toluene solution dispersion having an average particle diameter of 0.5 μm. . Toluene was distilled off while heating the aqueous dispersion to obtain an aqueous dispersion having a solid content of about 50%. Example 1
The aqueous dispersions using the zinc salt of the salicylic acid derivative of Examples 4 to 4 (Examples 5 to 8) were milky white, but the aqueous dispersions using the zinc salt of the salicylic acid derivative of Comparative Examples 1 and 2 (Comparative Example 3 ~
4) was brownish white.

Examples 9 to 12, Comparative Examples 5 to 6 Aqueous dispersions of salicylic acid derivative zinc produced in Examples 5 to 8 and Comparative Examples 3 to 4 were mixed with various auxiliaries in the following composition and coated. A liquid was obtained. Next, apply the coating liquid to an absolute dry weight of 50 g /
a fine paper of m ^2, was coated with a coating rod to a dry solid content 5 g / m ^2, to prepare a dry developer sheet 60 ° C.. The whiteness of the coated surface of the color developing sheets (Examples 9 to 12) prepared using the dispersions of Examples 5 to 8 is shown in Table 2 below. The whiteness of the surface of the color developing sheets (Comparative Examples 5 to 6) using the dispersions of Comparative Examples 3 to 4 was lower than that of the color developing sheets using the dispersions of Examples 5 to 8.

[Composition of coating liquid] Aqueous dispersion of zinc salt of salicylic acid derivative 4 parts Calcium carbonate 20 parts Sodium hexametaphosphate 0.1 part Kuraray PVA 117 (10% aqueous solution) 20 parts Water 55.9 parts

[0056]

[Table 2]

Regarding the color developing sheets of Examples 9 to 12,
Further, the coated surface was subjected to a NOx yellowing test and a color development test.
The results are shown in Table 3 below.

Example 13 Zinc 3- (α-methylbenzyl) salicylate, Zinc 5- (α-methylbenzyl) salicylate, Zinc 3,5-di (α-methylbenzyl) salicylate, 3-((α-methylbenzyl) )-Five-
Zinc (1 ', 3'-diphenylbutyl) salicylate and 3-
(1 ', 3'-diphenylbutyl) -5- (α-methylbenzyl) salicylate zinc, weight ratio 12: 12: 5
Using a toluene solution consisting of a mixture of 0:13:13, a milky white dispersion was obtained in the same manner as in Examples 5 to 8, and a coating liquid was prepared in the same manner as in Examples 9 to 12. A color development sheet was prepared using the coating solution. Coating surface NO
x Yellowing test and color development test were conducted. The results are shown in Table 3 below.

Comparative Examples 7 to 10 (Comparative Example 7); Zinc 3,5-di (α-methylbenzyl) salicylate, (Comparative Example 8); Zinc 3- (α-methylbenzyl) salicylate, 5- (α -Methylbenzyl) zinc salicylate in a weight ratio of 50:50, (Comparative Example 9); 3,5-di (α-methylbenzyl) zinc salicylate,
From zinc 3-((α-methylbenzyl) -5- (1 ', 3'-diphenylbutyl) salicylate and zinc 3- (1', 3'-diphenylbutyl) -5- (α-methylbenzyl) salicylate A mixture having a weight ratio of 80:10:10, (Comparative Example 1
0); 3- (α-methylbenzyl) zinc salicylate, 5-
Zinc (α-methylbenzyl) salicylate, Zinc 3,5-di (α-methylbenzyl) salicylate, Zinc 3-((α-methylbenzyl) -5- (1 ′, 3′-diphenylbutyl) salicylate and 3- (1 ′, 3′-diphenylbutyl) -5- (α-methylbenzyl) salicylate zinc, weight ratio 1: 1:
A color developing sheet was prepared in the same manner as in Example 13 using the mixture of 10:44:44. A NOx yellowing test and a color development test of the coated surface were performed. The results are shown in Table 3 below.

[0060]

[Table 3]

[0061]

When the developer of the present invention is used as a developer sheet for pressure-sensitive paper, it shows less yellowing due to nitrogen-oxidizing gas than conventional developers and is excellent in coloring speed and saturated coloring density. ing. Further, the developer of the present invention obtained by reacting salicylic acids with styrene in the presence of a polyvalent metal salt of an organic carboxylic acid is less colored. Therefore, the whiteness of the coated surface of the sheet coated with the developer of the present invention is high without any special treatment. Further, when used as a color developing aid for thermal paper, light resistance is improved.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location C07C 65/105 8930-4H C09K 9/02 Z 7188-4H

Claims (14)

[Claims] 1. A polyvalent metal salt of a salicylic acid derivative,
The salicylic acid derivative is (a) 5 to 60% by weight, (b) 15 to 70% by weight, based on the total of the following (a), (b) and (c):
And (c) a color developer comprising 10 to 40% by weight. (A) 1 mol of salicylic acid is reacted with 1 mol of salicylic acid derivative (b) 1 mol of salicylic acid is reacted with styrene, 2 mol of salicylic acid derivative is reacted (c) 1 mol of salicylic acid is reacted with 3 mol of styrene Reacted salicylic acid derivative 2. The developer according to claim 1, wherein the salicylic acid derivative is obtained by reacting salicylic acid and styrene in the presence of a polyvalent metal salt of an organic carboxylic acid. 3. The color developer according to claim 1, wherein the polyvalent metal salt of claim 1 is the same as the polyvalent metal salt of the organic carboxylic acid of claim 2. 4. The developer according to claim 1, wherein the metal in the polyvalent metal salt of the salicylic acid derivative is selected from zinc, calcium, barium, lead, aluminum, zirconium, vanadium and tin. 5. The color developer according to claim 1, wherein the metal in the polyvalent metal salt of the salicylic acid derivative is zinc. 6. The molar ratio of salicylic acid and styrene is
The color developing agent according to claim 2, which is 1: 1.5 to 3.0. 7. The developer according to claim 2, wherein the organic carboxylic acid is salicylic acid or a nucleus-substituted salicylic acid. 8. The color developer according to claim 2, wherein the amount of the polyvalent metal salt of an organic carboxylic acid is 1 to 100 parts by weight per 100 parts by weight of salicylic acid. 9. The developer according to claim 1, in the presence of a dispersant,
A dispersion that is dispersed in water. 10. The developer according to claim 9, wherein the dispersant is a salt of sulfonated polystyrene having a sulfonation degree of 40 to 70 mol%. 11. The method according to claim 9, comprising fine particles of 2 microns or less.
Dispersion as described. 12. The dispersion according to claim 9, which further contains an inorganic pigment or polymer fine powder and a binder. 13. A color-developing sheet having a layer containing a polyvalent metal salt of a salicylic acid derivative according to claim 1. 14. The color developing sheet according to claim 13, wherein the layer is formed of the dispersion according to claim 9.