JPH083107A - Polyvalent metal salt of salicylic acid derivative and its production - Google Patents

Abstract

PURPOSE:To obtain the subject aralkyl-substituted compound useful as a developer for pressure-sensitive recording sheets excellent in stability to both light and NOx. CONSTITUTION:This compound is obtained by making a polyvalent metal compound act on an aralkyl-substituted salicylic acid derivative prepared by making salicylic acid act on a styrene derivative [e.g. a compound of the formula (R1-R3 are each H or an alkyl ; X1 and X2 are each H, an alkyl, alkoxyl, aralkyl, aryl or halogen)] in the presence of an acid. In this case, the styrene derivative to be used is <=100ppm (esp. <=20ppm) in the content of a catechol derivative (esp. 4-t-butylcatechol). The polyvalent metal is e.g. Mg, Zn, Ni, Al, Ca (esp. Zn). In this reaction, use of the salicylic acid <=5000ppm (esp. 5500ppm) in phenol, content can further enhance the effectiveness of the present invention.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a polyvalent metal salt of an aralkyl-substituted salicylic acid derivative, and a pressure-sensitive recording sheet using the polyvalent metal salt.

[0002]

2. Description of the Related Art Conventionally, polyvalent metal salts of 3,5-disubstituted salicylic acid derivatives have been known to be useful as a color developer for pressure-sensitive recording sheets (for example, Japanese Patent Publication No. 51-.
No. 25174). Furthermore, various aralkyl-substituted polyvalent metal salts of salicylic acid derivatives have been proposed as developers for pressure-sensitive recording sheets. For example, a polyvalent metal salt of an aralkyl-substituted salicylic acid derivative produced by allowing a polyvalent metal compound to act on an aralkyl-substituted salicylic acid derivative obtained by reacting salicylic acid and a styrene derivative (see, for example, JP-A-62-62). -84045, JP-A-63-112537, JP-A-2-91
043, JP-A-3-222793, and JP-A-4-129789) are known.

Since the styrene derivative used in these production methods is relatively unstable to light, oxygen, etc., the styrene derivative is generally mixed with a catechol derivative as a stabilizer. However, the amount of catechol derivative mixed varies depending on the lot of styrene derivative obtained, and a large amount (5
A catechol derivative (of about 00 ppm) is often mixed. A styrene derivative having a high content of such a catechol derivative is added to an aralkyl-substituted salicylic acid derivative obtained by acting on salicylic acid, and a polyvalent metal compound of the aralkyl-substituted salicylic acid derivative produced by further acting a polyvalent metal compound. It has been found that when a metal salt is used as a developer for a pressure-sensitive recording sheet, its storage stability (for example, light resistance and NOx resistance) is poor and the pressure-sensitive recording sheet tends to yellow.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a polyvalent metal salt of an aralkyl-substituted salicylic acid derivative, which is useful as a developer for a pressure-sensitive recording sheet.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention have arrived at the present invention as a result of extensive studies on a method for producing a polyvalent metal salt of an aralkyl-substituted salicylic acid derivative. That is, the present invention, when the aralkyl-substituted salicylic acid derivative obtained by reacting salicylic acid and a styrene derivative in the presence of an acid, a polyvalent metal compound, to produce a polyvalent metal salt of the salicylic acid derivative. The present invention relates to a method for producing a polyvalent metal salt of an aralkyl-substituted salicylic acid derivative using a styrene derivative having a catechol derivative content of 100 ppm or less. Furthermore, the present invention relates to a polyvalent metal salt of an aralkyl-substituted salicylic acid derivative obtained by this method, and a pressure-sensitive recording sheet using the same.

The styrene derivative used in the production method of the present invention is a styrene derivative having a catechol derivative content of 100 ppm or less, preferably a catechol derivative content of 70 ppm or less, more preferably 50 pp.
m or less, more preferably 30 ppm or less, and particularly preferably 20 ppm or less. A styrene derivative having a catechol derivative content of 100 ppm or less is, for example, a method of distilling and purifying an industrially available styrene derivative, a base (for example, sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, potassium hydrogen carbonate). , Sodium hydride), or a method of distilling and purifying after treatment with a base. The amount of the catechol derivative can be determined by an analytical means such as high performance liquid chromatography.

Content of catechol derivative is 100 ppm
When a styrene derivative exceeding the above is used, the storage stability (for example, light resistance and NOx resistance) of the pressure-sensitive recording sheet using the resulting polyvalent metal salt of the aralkyl-substituted salicylic acid derivative as a developer is poor. Examples of the styrene derivative used in the present invention include a styrene derivative represented by the general formula (1) (formula 1). These styrene derivatives may be used alone or in combination.

[0008]

Embedded image (In the formula, R ₁ , R ₂ and R ₃ represent a hydrogen atom or an alkyl group, X ₁ and X ₂ represent a hydrogen atom, an alkyl group,
Represents an alkoxy group, aralkyl group, aryl group or halogen atom)

In the general formula (1), R ₁ , R ₂ and R ₃ represent a hydrogen atom or an alkyl group, preferably
A hydrogen atom or an alkyl group having 1 to 4 carbon atoms, particularly preferably a hydrogen atom. X ₁ and X ₂ represent a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group or a halogen atom, preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, Aralkyl group having 7 to 10 carbon atoms, 6 carbon atoms
It is an aryl group of 10 to, a fluorine atom, a chlorine atom, and a bromine atom, and a hydrogen atom is particularly preferable.

Examples of the styrene derivative include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 4-ethylstyrene, 3-isopropylstyrene, 4-isopropylstyrene and 4-n. -Butylstyrene, 4-tert-butylstyrene, 4-cyclohexylstyrene, 4-n-octylstyrene, 4-n-decylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3-methoxystyrene, 4 -Methoxystyrene, 4-ethoxystyrene, α-methylstyrene, α-ethylstyrene, α-n
-Butylstyrene, α-isobutylstyrene, α, β-
Dimethylstyrene, α, β-diethylstyrene, α-methyl-β-isopropylstyrene, α-n-propyl-
β-methylstyrene, 4- (α-methylbenzyl) styrene, 4- (α, α-dimethylbenzyl) styrene, 4
-Phenyl styrene, 4-fluoro styrene, 2-chloro styrene, 3-chloro styrene, 4-chloro styrene, 4-bromo styrene etc. can be mentioned, but it is not limited to these. These styrene derivatives may be used alone or in combination. Particularly preferred is styrene.

Examples of the catechol derivative which is a problem in the present invention include catechol, 3-methylcatechol, 4-methylcatechol, 4-ethylcatechol and 3
It is -tert-butylcatechol, 4-tert-butylcatechol, 4-tert-amylcatechol, 4-cyclohexylcatechol, 4-tert-octylcatechol, 4-nonylcatechol, 3,5-dimethylcatechol and the like. Above all, the content of 4-tert-butylcatechol is 100
Preference is given to using ppm of styrene derivatives or less.

Further, salicylic acid is generally produced by reacting phenol with carbon dioxide in the presence of a base, and a large amount of unreacted phenol may often remain in salicylic acid. In the present invention,
It is preferable to use salicylic acid having a low phenol content because the effect of the present invention can be further enhanced. The salicylic acid used in the present invention preferably has a phenol content of 5000 ppm or less, and more preferably 400 ppm.
The salicylic acid content is 0 ppm or less, more preferably 2000 ppm or less, and particularly preferably 500 ppm or less. The amount of phenol can be determined by analytical means such as high performance liquid chromatography.

In the production method of the present invention, the amount of the styrene derivative used is not particularly limited, but it is preferably about 1 to 10 times by mole, more preferably 1.5 to 8 times by mole with respect to salicylic acid. Mol, particularly preferably,
It is 2 to 6 times the molar amount. The reaction of salicylic acid with the styrene derivative is carried out in the presence of acid. As the acid, for example,
Hydrochloric acid, sulfuric acid, hydrogen bromide, hydrogen chloride, hydrogen fluoride, phosphoric acid, polyphosphoric acid, acetic acid, propionic acid, chloroacetic acid, trichloroacetic acid, trifluoroacetic acid, methanesulfonic acid,
Trifluoromethanesulfonic acid, ethanesulfonic acid, butanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, p-chlorobenzenesulfonic acid, β-naphthalenesulfonic acid, stannic chloride, ferric chloride, chlorinated Zinc, aluminum chloride, boron trifluoride, titanium tetrachloride, Nafion-H (trade name, Dupont
(Manufactured by the company) and the like, but the invention is not limited thereto. These acids can be used alone,
Alternatively, a plurality of them can be used in combination.

The reaction between salicylic acid and the styrene derivative can be carried out in the absence of an organic solvent, but it can also be carried out in the presence of an organic solvent. Examples of the organic solvent include hydrocarbon solvents such as hexane, octane, decane, cyclohexane, benzene, toluene and xylene, ester solvents such as ethyl acetate, butyl acetate and amyl acetate, carboxylic acid solvents such as acetic acid and propionic acid. Solvents, ether solvents such as tetrahydrofuran and dioxane, dichloromethane, 1,2-dichloroethane, tetrachloromethane,
1,1-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1,2,2-
Halogenated hydrocarbon system such as tetrachloroethane, chlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, 1,2,4-trichlorobenzene, o-chlorotoluene, m-chlorotoluene, p-chlorotoluene Examples of the solvent include methanol, ethanol, isopropanol, methyl cellosolve, and alcohol solvents such as ethylene glycol.
It is not limited to these. These organic solvents may be used alone or in combination. The capacity of the organic solvent used is not particularly limited, but use of a large amount itself only lowers the working efficiency, the production efficiency and the like. Usually, the used volume of the organic solvent is 100% with respect to the weight of salicylic acid.
(Volume / weight) times or less is preferable.

In the reaction of salicylic acid and styrene derivative, the reaction temperature is about -20 to 150 ° C, more preferably 0 to 120 ° C. The reaction can be carried out under atmospheric pressure, but can also be carried out under reduced pressure or under increased pressure. The aralkyl-substituted salicylic acid derivative produced by reacting salicylic acid with a styrene derivative is a styrene derivative, and / or a reactive styrene oligomer derived from the styrene derivative in the presence of an acid, can be widely converted into salicylic acid. It is a salicylic acid derivative in which the salicylic acid skeleton has been substituted with at least one aralkyl group.

Examples of the aralkyl-substituted salicylic acid derivative include 3- (α-methylbenzyl) salicylic acid, 5- (α-methylbenzyl) salicylic acid, and 3- (α-methylbenzyl) salicylic acid.
(Α, α-Dimethylbenzyl) salicylic acid, 5- (α,
α-dimethylbenzyl) 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-di [1- (4'-methylphenyl) ethyl] salicylic acid, 3- (1 ', 3'-diphenylbutyl) salicylic acid, 5- (1', 3'-diphenylbutyl) salicylic acid, 3
-[Α-Methyl-4 '-(α'-methylbenzyl) benzyl] salicylic acid, 5- [α-methyl-4'-(α'-methylbenzyl) benzyl] salicylic acid, 3- (α-methylbenzyl)- 5- (1 ', 3'-diphenylbutyl) salicylic acid, 3- (1', 3'-diphenylbutyl) -5- (α-
Methylbenzyl) salicylic acid, 3- (α, α-dimethylbenzyl) -5- (1 ′, 3′-dimethyl-1 ′, 3′-diphenylbutyl) salicylic acid, 3- (1 ′, 3′-dimethyl-
1 ', 3'-diphenylbutyl) -5- (α, α-dimethylbenzyl) salicylic acid, 3- [1- (4'-methylphenyl) ethyl] -5- [1', 3'-bis (4- Methylphenyl) butyl] salicylic acid, 3- [1 ', 3'-bis (4-methylphenyl) butyl] -5- [1- (4'-methylphenyl) ethyl] salicylic acid, and further a monomer unit of a styrene derivative Examples thereof include, but are not limited to, polyaralkylated salicylic acid in which 4 or more are substituted.

The aralkyl-substituted salicylic acid derivative produced by reacting salicylic acid and a styrene derivative is
It can be taken out from the reaction system by a known method, or can be used for the subsequent reaction with the polyvalent metal compound without being taken out from the reaction system. When these aralkyl-substituted salicylic acid derivatives are allowed to act on the polyvalent metal compound, the aralkyl-substituted salicylic acid derivatives may be used alone or in combination.

The polyvalent metal salt of the aralkyl-substituted salicylic acid derivative is the above-mentioned polyvalent metal salt of the aralkyl-substituted salicylic acid derivative. Specific examples of the polyvalent metal include magnesium, zinc, nickel, aluminum, and calcium s4, and zinc is particularly preferable. These polyvalent metal salts of salicylic acid derivatives may be polyvalent metal salts of mixed salicylic acid derivatives obtained by polyvalent metal salification using a plurality of aralkyl-substituted salicylic acid derivatives.

The method for producing the polyvalent metal salt of the aralkyl-substituted salicylic acid derivative is not particularly limited, and a known method can be applied. For example, it is produced by melting one or more aralkyl-substituted salicylic acid derivative and a polyvalent metal compound (eg, polyvalent metal oxide, hydroxide, carbonate, silicate, organic carboxylate). Method (melting method) or water-soluble salts such as alkali metal salts, amine salts or ammonium salts of one or more aralkyl-substituted salicylic acid derivatives, and water-soluble polyvalent metal compounds (eg, zinc sulfate, sulfuric acid) And magnesium sulfate, calcium sulfate, aluminum sulfate and other sulfates, zinc chloride, magnesium chloride, calcium chloride, nickel chloride, aluminum chloride and other chlorides, zinc acetate and other acetates, etc.) in the presence of water The method (double decomposition method) can be applied.

When a polyvalent metal salt of an aralkyl-substituted salicylic acid derivative is produced by the metathesis method, a general method is as follows:
An equivalent amount of an alkali metal compound (eg, lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate), or an amine compound (eg, methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, Triethylamine, ethanolamine, isopropanolamine, triethanolamine, 2-dimethylaminoethanol, morpholine, ammonia) in an aqueous solution to prepare an alkali metal salt, amine salt or ammonium salt of an aralkyl-substituted salicylic acid derivative. It is produced as a polyvalent metal salt of a sparingly water-soluble or water-insoluble aralkyl-substituted salicylic acid derivative by allowing a water-soluble polyvalent metal compound to act.

The water-soluble polyvalent metal compound is 2
Monovalent, trivalent or tetravalent metal compounds are preferred. As the polyvalent metal compound, for example, sulfate such as zinc sulfate, magnesium sulfate, calcium sulfate, aluminum sulfate, zinc chloride, magnesium chloride, calcium chloride, barium chloride, nickel chloride, cobalt chloride, chloride such as aluminum chloride, Examples thereof include acetate salts such as zinc acetate and manganese acetate. These polyvalent metal compounds may be used alone or in combination. The amount of the polyvalent metal compound used is, for example, 0.8 to 1.5 equivalents, preferably 1.0 to 1.2 equivalents, relative to 1 equivalent of the alkali metal salt of the aralkyl-substituted salicylic acid derivative. In this case, the equivalent amount means that the polyvalent metal compound is based on 1 mol of the alkali metal salt of the aralkyl-substituted salicylic acid derivative.
For example, in the case of a divalent metal compound (for example, zinc sulfate), 0.5 mol of the divalent metal compound is 1 equivalent.

A pressure-sensitive recording sheet using a polyvalent metal salt of an aralkyl-substituted salicylic acid derivative obtained by the production method of the present invention as a developer will be described below. When a polyvalent metal salt of an aralkyl-substituted salicylic acid derivative is produced by a metathesis method, the polyvalent metal salt generally precipitates in an aqueous medium within a short time. The polyvalent metal salt can be easily filtered and isolated from the reaction system by a usual method without using a special device. After the filtration, the dispersion liquid of the color developer for the pressure sensitive recording sheet is prepared by drying and performing the dispersion treatment by a known means or method, or by performing the dispersion treatment directly after the filtration without a drying step. be able to.

In preparing the dispersion liquid of the color developer, the dispersion treatment of the polyvalent metal salt of the aralkyl-substituted salicylic acid derivative is usually performed in an aqueous medium to obtain an aqueous dispersion liquid of the color developer. . Usually, the color developer has an average particle size of 3 μm.
Hereinafter, the particles are pulverized and dispersed, preferably to a particle size of 2 μm or less. As a method for obtaining an aqueous dispersion, for example, a polyvalent metal salt of an aralkyl-substituted salicylic acid derivative, in an aqueous medium, as a disperser, for example, ball mill, attritor, sand grinder, pebble mill, covol mill,
Using a dyno mill, high speed impeller disperser, high speed stone mill, etc., a method of pulverizing and dispersing to obtain an aqueous dispersion,
After dissolving the aralkyl-substituted polyvalent metal salt of salicylic acid derivative in an organic solvent, in an aqueous medium, for example, using an ultrasonic disperser, a homogenizer, a homomixer, an emulsification dispersion treatment, to remove the organic solvent , A method of obtaining an aqueous dispersion, and the like.

In the above method, the organic solvent used is preferably one having a low solubility in water, a high solubility of the color developer and a relatively low boiling point. Examples of the organic solvent include hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and 1-methylnaphthalene, dichloromethane, chloroform, tetrachloroethylene, 1,2-dichloroethane, 1,1,
1-trichloroethane, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, chlorobenzene, o-dichlorobenzene, m-dichlorobenzene,
Halogenated hydrocarbon solvents such as p-dichlorobenzene, o-chlorotoluene, m-chlorotoluene and p-chlorotoluene, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ethyl acetate, butyl acetate, amyl acetate, etc. Examples thereof include ester solvents, alcohol solvents such as butanol, pentanol, hexanol, and cyclohexanol. These organic solvents may be used alone or in combination of two or more.

The amount of the organic solvent used is not particularly limited, but is usually about 5 to 500 parts by weight, more preferably 20 parts by weight, relative to 100 parts by weight of the aralkyl-substituted polyvalent metal salt of the salicylic acid derivative. It is about 300 parts by weight. In this case, the emulsification dispersion treatment is carried out at a temperature equal to or lower than the boiling point of the organic solvent, and is carried out under atmospheric pressure or under pressure. After the dispersion treatment, the organic solvent is distilled off to obtain an aqueous dispersion of the color developer. As a method of distilling off the organic solvent, under atmospheric pressure or under reduced pressure, heating above the boiling point of the organic solvent,
The organic solvent can be distilled off. The aqueous dispersion of the developer thus obtained can be further subjected to a dispersion treatment, if desired, using the above-mentioned disperser (for example, a sand grinder).

An ionic or nonionic surfactant is preferable as the dispersant used for dispersion in an aqueous medium. Examples of the dispersant include polyvinyl alcohol, alkyl-modified polyvinyl alcohol, cyanoethyl-modified polyvinyl alcohol, ether-modified polyvinyl alcohol, polyacrylamide, polyacrylic acid, acrylamide / alkyl acrylate copolymer, alkali metal salt of polystyrene sulfonic acid, and maleic anhydride. Synthetic or natural polymer compounds such as acid / isobutylene copolymer, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinylpyrrolidone, starch and its derivatives, casein, gum arabic, agar, gelatin, alkali metal salts of alkylbenzenesulfonic acid, alkylnaphthalenesulfonic acid Alkali metal salts, dialkyl sulfosuccinic acid alkali metal salts, alkyl sulfonic acid alkali metal salts, polyoxy Chi alkylether,
Examples thereof include polyoxyethylene alkyl phenyl ether and polyhydric alcohol fatty acid ester. These dispersants may be used alone or in combination.

The amount of the dispersant used is not particularly limited, but is usually about 1 to 30 parts by weight with respect to 100 parts by weight of the aralkyl-substituted polyvalent metal salt of the salicylic acid derivative. The amount of water used when preparing the aqueous dispersion is not particularly limited, in consideration of handling, etc., generally, the concentration of the developer in the aqueous dispersion,
3 to 50% by weight, more preferably 5 to 40% by weight
It is preferred to use an amount that is moderate.

In the coating liquid for forming the developer layer, the aqueous dispersion of the developer obtained as described above is usually further mixed with a binder, a pigment and the like. The binder is not particularly limited, for example, polyvinyl alcohol, casein, starch and its derivatives,
Examples thereof include synthetic or natural polymer compounds such as gum arabic, methyl cellulose, carboxymethyl cellulose, polyacrylic acid, styrene / butadiene copolymer latex, and latexes such as acrylic acid ester latex. Examples of the pigment include zinc oxide, zinc carbonate,
Calcium carbonate, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, titanium oxide, talc,
Examples thereof include kaolin, activated clay, diatomaceous earth, aluminum hydroxide, magnesium hydroxide, alumina and silica. Further, if desired, various additives (for example, an ultraviolet absorber, a defoaming agent,
pH adjusting agent, viscosity adjusting agent, plasticizer, organic polymer compound, etc.) may be added.

The coating liquid thus prepared for preparing the pressure-sensitive recording sheet is, for example, an air knife coater,
A coating device such as a blade coater, roll coater, size press coater, curtain coater, etc. is used to form a color developer layer by coating on a support (for example, paper, plastic sheet, synthetic paper, or a composite sheet combining these). Then, a pressure-sensitive recording sheet can be produced.
The weight (that is, the coating amount) of the developer layer on the support is not particularly limited, but is usually 0.5 g / dry weight.
m ² or more, preferably 0.5 to 10 g / m ² .
Further, in the developer layer, the ratio of the polyvalent metal salt of the aralkyl-substituted salicylic acid derivative produced by the method of the present invention is
Usually, it is 5% by weight or more, preferably 5 to 70% by weight.

The form of the pressure-sensitive recording sheet of the present invention is as follows.
Although not particularly limited, for example, a lower sheet used in combination with an upper sheet in which microcapsules containing an electron-donating color forming compound and a capsule oil are applied to the back surface of the sheet, multiple sheets are copied. For the purpose of inserting the intermediate sheet between the upper sheet and the lower sheet, the developer sheet is provided on the front surface of the sheet and the microcapsule layer is provided on the back surface of the sheet, and further, the microsheet is formed on the same surface of the sheet. There is a single copy sheet coated with both the capsule and the color developer. The above-mentioned microcapsules are prepared by dissolving an electron-donating color-forming compound in capsule oil, and subjecting the solution to known methods such as coacervation method, interfacial polymerization method, internal polymerization method, phase separation method, and external polymerization method. It can be manufactured by various microencapsulation methods.

Examples of the electron-donating color-forming compound include triarylmethane compounds, diarylmethane compounds, rhodamine-lactam compounds, fluorane compounds, indolylphthalide compounds, pyridine compounds, spiro compounds, Various known compounds such as fluorene compounds and phenothiazine compounds can be mentioned.

As the capsule oil, for example, cottonseed oil, castor oil, kerosene, paraffin, chlorinated paraffin,
Naphthene oil, alkylated biphenyl, alkylated terphenyl, alkylated naphthalene, diarylalkane,
Examples include various oils such as hydrogenated terphenyl and dialkyl phthalate. These capsule oils may be used alone or in combination.

[0033]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
In addition,% represents weight%. Example 1 Salicylic acid 20.7 containing 300 ppm of phenol
g (0.15 mol), 10 ml of acetic acid and 5 g of methanesulfonic acid were placed in a glass reaction vessel and heated to 110 ° C.
While stirring, 62.4 g (0.6 mol) of styrene containing 100 ppm of 4-tert-butylcatechol was added dropwise to the solution. After the addition was completed, the reaction was continued for another 1 hour, then cooled, 100 ml of heptane was added to the reaction solution, and water was added thereto.
The organic layer was washed several times with 0 ml. After washing with water, 200 ml of 2N aqueous sodium hydroxide solution was added, and the organic layer was separated and removed. After adding 100 ml of heptane to the aqueous layer and acidifying the aqueous layer with hydrochloric acid, the organic layer was separated and heptane was removed.
A mixture of g aralkyl-substituted salicylic acid derivative was obtained. When the residual reaction mixture was analyzed by HPLC (high performance liquid chromatography), 3,5-di (α-
Methylbenzyl) salicylic acid 59% by weight, 3-α-methylbenzyl-5- (1 ′, 3′-diphenylbutyl) salicylic acid 10% by weight, 3- (1 ′, 3′-diphenylbutyl)-
It was 19% by weight of 5- (α-methylbenzyl) salicylic acid and 12% by weight of a salicylic acid component in which 4 or more other styrenes were substituted. This mixture was added with sodium hydroxide (6
g) was dissolved in an aqueous solution (500 ml), and while stirring the solution, zinc sulfate heptahydrate (21.5 g) was added at 25 ° C. Furthermore, after stirring at 25 ° C. for 1 hour, the precipitated zinc salt of the aralkyl-substituted salicylic acid derivative was filtered and dried to obtain 85 g of zinc salt. A mixture of 25 g of the salicylic acid derivative zinc salt, 120 g of calcium carbonate and 200 g of water was subjected to atomization dispersion treatment with a sand grinder so that the average particle size of the developer dispersion particles was 1.5 μm to obtain a dispersion liquid of the developer. It was To this dispersion, 100 g of a 10% polyvinyl alcohol (PVA-117, manufactured by Kuraray) aqueous solution and 10 g of 50% carboxy-modified SBR latex (SN-307, manufactured by Sumitomo Nogatak) were added to give a solid content concentration of 20%. Water was added so as to obtain an aqueous dispersion coating liquid of a color developer. The aqueous dispersion coating liquid of the color developer was applied to high-quality paper (50 g / m ² ) so that the coating amount (weight of the color developer layer) at the time of drying was 5.0 g / m ^2, and dried. A pressure-sensitive recording sheet (lower sheet) was produced.

Examples 2 to 6 In Example 1, 4-tert-butylcatechol was added to 10
Instead of using 62.4 g of styrene containing 0 ppm, the content of each styrene is 70 ppm (Example 2), 50 ppm (Example 3), 30 ppm (Example 4), 20 ppm (Example 5), and Except for using 62.4 g of styrene not contained (Example 6),
By the method described in Example 1, a zinc salt of an aralkyl-substituted salicylic acid derivative was obtained. Furthermore, a pressure-sensitive recording sheet was prepared by using the zinc salt by the method described in Example 1.

Comparative Examples 1 to 3 In Example 1, 4-tert-butylcatechol was added to 10
Instead of using 62.4 g of styrene containing 0 ppm, the content is 150 ppm (Comparative Example 1), 200 ppm
Comparative Example 2 A zinc salt of an aralkyl-substituted salicylic acid derivative was obtained by the method described in Example 1 except that 62.4 g of each styrene of 400 ppm (Comparative Example 3) was used. Furthermore, a pressure-sensitive recording sheet was prepared by using the zinc salt by the method described in Example 1.

Each pressure-sensitive recording sheet (lower sheet) obtained in Examples and Comparative Examples was evaluated by the following method. The results are shown in Table 1 (Table 1). Evaluation of Pressure Sensitive Recording Sheet (Whiteness of Untreated Pressure Sensitive Recording Sheet) The whiteness of each pressure sensitive recording sheet was measured using a Σ-80 color difference meter. The whiteness is represented by a WB value. The larger the value, the better the whiteness. (Light resistance test) Each pressure-sensitive recording sheet was heated at 40 ° C. using a carbon arc fade meter (manufactured by Suga Test Instruments Co., Ltd.)
Illuminated for hours. After the test, the whiteness was measured using a Σ-80 color difference meter. The change (WB value) from the value of the pressure-sensitive recording sheet before the light resistance test is shown. The smaller the difference in this change, the smaller the yellowing and the better the light resistance. (NOx resistance test) Based on JIS-L-1055 (testing method for fastness of nitric oxide gas of dyed materials and dyes), each pressure-sensitive recording sheet is subjected to NOx gas generated by reaction of NaNO ₂ and H ₃ PO _4. It was stored in an airtight closed container for 2 hours. After the test, the whiteness was measured using a Σ-80 color difference meter. The change (WB value) from the value of the pressure-sensitive recording sheet before the NOx resistance test was shown. The smaller the difference in this change, the smaller the yellowing and the better the NOx resistance.

[0037]

[Table 1] From the results of Table 1, the pressure-sensitive recording sheet using the zinc salt of the aralkyl-substituted salicylic acid derivative produced by the method of the present invention is excellent in light stability and NOx stability,
It became clear that there was little yellowing.

[0038]

According to the present invention, there is provided a method for producing a polyvalent metal salt of an aralkyl-substituted salicylic acid derivative, which is useful as a color developer for a pressure-sensitive recording sheet having excellent light stability and NOx stability. Became possible.

Front page continuation (72) Inventor Kiyoharu Hasegawa 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd.

Claims (5)

[Claims] 1. A polyvalent metal compound is allowed to act on an aralkyl-substituted salicylic acid derivative obtained by reacting salicylic acid and a styrene derivative in the presence of an acid, to produce a polyvalent metal salt of the salicylic acid derivative, A method for producing a polyvalent metal salt of an aralkyl-substituted salicylic acid derivative, which comprises using a styrene derivative having a catechol derivative content of 100 ppm or less. 2. The production method according to claim 1, wherein the catechol derivative is 4-tert-butylcatechol. 3. Salicylic acid has a phenol content of 5
The salicylic acid content is 000 ppm or less.
The manufacturing method described. 4. A polyvalent metal salt of an aralkyl-substituted salicylic acid derivative produced by the production method according to claim 1. 5. A pressure-sensitive recording sheet comprising a support and a polyvalent metal salt of an aralkyl-substituted salicylic acid derivative produced by the method according to claim 1, 2 or 3.