JPH0780352B2 - Dispersant for color developer for pressure sensitive paper - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dispersant for an aromatic carboxylic acid type developer for pressure-sensitive paper.

[Prior Art] As a dispersant for a conventional aromatic carboxylic acid type color developer, polystyrene sulfonic acid sodium salt is known (for example, JP-A-51-44010).

[Problems to be Solved by the Invention] However, in this product, the stability and color development of the dispersion were not sufficient.

[Means for Solving the Problems] The present inventors have arrived at the present invention as a result of studying a dispersant for an aromatic carboxylic acid-based developer for pressure-sensitive paper, which has sufficient stability and color development of the dispersion. .

That is, the present invention is a sulfonic acid (salt) group-containing monomer (A),
Aromatic carboxylic acid for pressure-sensitive paper comprising a water-soluble or water-dispersible polymer having a carboxylic acid (salt) group-containing monomer (B) and optionally a hydrophilic nonionic vinyl monomer (C) as a constituent unit. It is a dispersant for a color developer.

As the water-soluble or water-dispersible polymer in the present invention, (I) styrene and (B) and optionally (C) a sulfonated product of a copolymer and / or a salt thereof, (II) sulfonic acid Examples of the copolymer include a (salt) group-containing monomer, (B) and optionally (C) as a constituent unit, and (I) is preferable.

(I) Sulfonated copolymer and / or salt thereof of styrenes and (B) and optionally (C) as a constituent unit: Examples of styrenes include styrene, α-methylstyrene and α.
-Examples include ethylstyrene.

Examples of (B) include unsaturated carboxylic acids or anhydrides thereof ((meth) acrylic acid, fumaric acid, (anhydrous) maleic acid, (anhydrous) itaconic acid, etc.) and the like, and salts thereof. Of these, preferred are maleic anhydride and (meth) acrylic acid.

Examples of (C) include amide group-containing vinyl monomers [(meth) acrylamide, N-methyl (meth) acrylamide, N
-Methylol (meth) acrylamide, N, N, -dimethylacrylamide, etc.], hydroxyl group-containing vinyl monomer [hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, triethylene glycol (meth) acrylate, (meth) Allyl alcohol, etc.] and the like. Among these, preferred is a hydroxyl group-containing vinyl monomer.

The content of styrene in the copolymer containing styrene and (B) and optionally (C) as a constituent unit (hereinafter abbreviated as polymer 1) is usually 10 to 90 mol%, preferably 30 to 90 mol. %, The content of (B) is usually 1 to 90 mol%, preferably 5 to
The content of 70 mol%, (C) is usually 0 to 80 mol%, preferably 0 to 60 mol%.

The molecular weight of the polymer 1 is usually 500 to 1,000,000, preferably
It is 2,000 to 500,000, and more preferably 3,000 to 100,000.

The sulfonated product of Polymer 1 can be produced by a known method in a solvent using an ordinary sulfonating agent.

As the solvent, those which are inert to sulfonating agents such as aliphatic halogenated hydrocarbons having 1 to 2 carbon atoms and nitrated aliphatic hydrocarbons having 1 to 3 carbon atoms are usually used.

Specific examples of the aliphatic halogenated hydrocarbon include 1,2-dichloroethane, methylene dichloride, ethyl chloride, carbon tetrachloride, 1,1-dichloroethane, 1,1,2,2-tetrachloroethane, chloroform and ethylene dichloride. Examples include bromide. Examples of the nitrated aliphatic hydrocarbon include nitromethane, nitroethane, 1-nitropropane, 2-nitropropane and the like. Preferably, it is an aliphatic halogenated hydrocarbon.

The dissolution of the polymer 1 depends on the molecular weight of the polymer 1, but the solvent
The polymer 1 is usually dissolved in an amount of 1 to 100 parts by weight, preferably 5 to 50 parts by weight, per 100 parts by weight.

As the sulfonating agent, anhydrous sulfuric acid, chlorosulfuric acid or the like is used. Sulfuric acid anhydride is preferred. Liquid sulfuric acid, liquid sulfuric acid are mixed with nitrogen, dry air, and other inert gases and 1,2
-Sulfuric anhydride diluted with a solvent inert to a sulfonating agent such as an aliphatic halogenated hydrocarbon having 1 to 2 carbon atoms such as dichloroethane or ethyl chloride can also be used. The concentration of anhydrous sulfuric acid diluted with an inert gas is usually 1 to 15% by volume, preferably 3
~ 5% by volume. The sulfuric anhydride concentration diluted with an inert solvent is usually 1 to 50% by weight, preferably 5 to 20% by weight.

It is also possible to use a complex of anhydrous sulfuric acid and a Lewis base. Examples of the Lewis base include trialkyl phosphates such as triethyl phosphate and trimethyl phosphate, fatty acid alkyl esters such as ethyl acetate and ethyl palmitate, ethers or thioethers such as dioxane, thioxane and diethyl ether. Preferred Lewis bases are trialkyl phosphates and aliphatic alkyl esters.

The amount of the sulfonating agent used is the styrene unit 1 of the polymer 1.
The amount is usually 0.4 to 2 mol per mol.

The sulfonation reaction is usually 0 to 80 ° C, preferably 10 to
Performed at 50 ° C. and anhydrous conditions.

Sulfonates are usually alkali metals such as sodium and potassium, hydroxides and carbonates such as alkaline earth metals such as calcium and magnesium, or ammonia,
Amines are neutralized with a neutralizing agent such as an alkylamine such as triethylamine, dimethylamine, laurylamine and stearylamine, an alkanolamine such as monoethanolamine and diethanolamine to form a salt.

Preferred are sodium salt, potassium salt, and ammonium salt.

The solvent is removed by a usual method such as liquid separation, filtration and distillation to obtain a water-dispersible or water-soluble aqueous liquid or powdery sulfonic acid (salt) group-containing polymer.

In addition to the above method, Japanese Patent Application 1-
The sulfonation can also be carried out by the methods described in the specifications of 81169, Japanese Patent Application No. 1-114593 and Japanese Patent Application No. 1-117832.

(II) Copolymer containing sulfonic acid (salt) group-containing monomer and (B) and optionally (C) as a constitutional unit: Aromatic hydrocarbon vinyl sulfone as the sulfonic acid (salt) group-containing monomer Examples thereof include acids, sulfonic acid group-containing (meth) acrylamides, sulfonic acid group-containing (meth) acrylates, aliphatic hydrocarbon vinyl sulfonic acids and salts thereof.

Specifically, the following monomers are included.

(A-1) Aromatic hydrocarbon vinyl sulfonic acid p- and o-styrene sulfonic acid, styrene disulfonic acid, α-methyl styrene sulfonic acid, vinylphenyl methane sulfonic acid, etc. and salts thereof (A-2) sulfonic acid group Containing (meth) acrylamide 2- (meth) acrylamide-2-methylpropanesulfonic acid, 3- (meth) acrylamidepropane-1-sulfonic acid, 2- (meth) acrylamidoethyl-1-sulfonic acid, 3- (meth) Acrylamide-2-hydroxypropanesulfonic acid, p- (meth) acrylamidomethylbenzenesulfonic acid, and salts thereof (A-3) Sulfonic acid group-containing (meth) acrylate 3- (meth) acryloyloxypropane-1-sulfone Acid, 4- (meth) acryloyloxybutane-1-sulfone Acid, 4- (meth) acryloyloxybutane-2-sulfonic acid, 2- (meth) acryloyloxyethyl-1-sulfonic acid, 3- (meth) acryloyloxy-2-hydroxypropanesulfonic acid, and salts thereof. (A-4) Aliphatic Hydrocarbon Vinyl Sulfonic Acid Vinyl Sulfonic Acid, (Meth) allyl Sulfonic Acid, etc. These Salts The salts of the sulfonic acid group-containing monomer include alkali metal salts such as sodium, potassium and lithium, and calcium. ,
Examples thereof include alkaline earth metal salts such as magnesium, ammonium salts, amine salts such as ethanolamine, diethanolamine, monomethylamine, trimethylamine and trimethylamine, and sodium salts, potassium salts and ammonium salts are preferable.

Examples of the monomers (B) and (C) that are copolymerized with the sulfonic acid (salt) group-containing monomer include the same ones as described above.

Examples of the salt of the carboxylic acid group-containing monomer include the same salts as those of the sulfonic acid group-containing monomer.

The content of the sulfonic acid (salt) group-containing monomer in the polymer (II) is usually 10 to 90 mol%, preferably 30 to 90 mol%,
The content of (B) is usually 1 to 90 mol%, preferably 5 to 70 mol%, and the content of (C) is usually 0 to 80 mol%, preferably 0.
~ 60 mol%.

The production of the polymer (II) is not particularly limited,
It can be produced by a usual solution polymerization method. For example, sulfonic acid (salt) group-containing monomer and (B) and optionally (C) are added to water; methyl alcohol, ethyl alcohol,
50% in a lower alkyl alcohol such as isopropyl alcohol; a solvent such as cellosolves such as methyl cellosolve and ethyl cellosolve, or a mixed solvent of two or more thereof.
Polymerize at ~ 150%. As the radical polymerization initiator, persulfate, azobisisobutyronitrile, benzoyl peroxide, dicumyl peroxide, etc. are used in an amount of 0.1 to 15% by weight based on the monomers. If necessary, a chain transfer agent such as lauryl mercaptan, thioglycolic acid or mercaptoethanol is used.

The molecular weight of the water-soluble or water-dispersible polymer in the present invention is usually 1,000 to 2,000,000, preferably 2,000 to 1,000,0.
00, more preferably 3,000 to 200,000. The molecular weight is
If it is less than 1,000, sufficient dispersibility cannot be obtained, and 2,000
When it exceeds 0,000, the water-soluble viscosity of the polymer increases,
Workability is reduced. When indicated by the viscosity of a 30% by weight aqueous solution,
Usually about 10-100,000 cps, preferably about 20-50,000
cps.

The content of the sulfonic acid group in the aqueous solution or the water-dispersible polymer is usually 10% by weight or more, preferably 20% by weight in the polymer, when it is represented by% by weight based on the polymer excluding the salt component. If it is less than 10% by weight, sufficient dispersibility cannot be obtained.

The aqueous solution or water-dispersible polymer according to the present invention is used as a dispersant when an aromatic carboxylic acid type developer is dispersed in water to obtain a color developer aqueous dispersion.

3-phenyl-5-as an aromatic carboxylic acid type developer
tert-Butylsalicylic acid, 2-chloro-3-phenyl-
5-Isopropylbenzoic acid, 3-benzyl-5-phenyl-salicylic acid, 3,5-diphenylsalicylic acid, 2-nitro-3- (2'-nitro-3-carboxyphenyl)
-5-phenylbenzoic acid, 3,3'-dimethyl-5,5'-methylenedisalicylic acid, 2-nitro-3- (3'-carboxybenzyl) -5-methylbenzoic acid, 3-methyl-5
-Phenylsalicylic acid, 3,5-di (4'-aminophenyl) -2-aminobenzoic acid, 3-methyl-5-benzylsalicylic acid, 2-nitro-3-methyl-5- (4'-methylbenzoyl) benzoic acid Acid, 3-methyl-5- {β-
(4'-Methoxyphenyl) vinyl} salicylic acid, 3,5
-Di- (β-phenethyl) salicylic acid, 3- (4'-chlorobenzyl) -5-tert-butylsalicylic acid, 3-te
rt-Butyl-5- (p-tert-butylbenzyl) salicylic acid, 3-cyclohexyl-5- (α, α-dimethylbenzyl) salicylic acid, 4-phenyl-5-benzoylsalicylic acid, 3,5-di (α, α) -Dimethylbenzyl) salicylic acid, 3- {4 '-(α, α-dimethylbenzyl) phenyl} -5- (α, α-dimethylbenzyl) salicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl)
Salicylic acid, 3-methyl-5-{(4'-ethoxycarbonyl) phenyl} salicylic acid, 4- (3'-carboxy-4'-hydroxy-5'-benzylphenyl) benzenesulfonic acid, 3-methyl-5- ( 5'-methylnaphthyl) salicylic acid, 3- (2'-hydroxy-1-naphthylmethyl) -5-phenylsalicylic acid, 2-hydroxy-1-benzyl-3-naphthoic acid, 3,3'-dicarboxy-2, 2'-dihydroxy-1,1'-dinaphthylmethane, 1-benzoyl-2-hydroxy-3-naphthoic acid, 1-chloro-4'-hydroxy-dinaphthylketone-3'-carboxylic acid, 1,4- Di (dimethylamino) -3
-Phenyl-2-naphthoic acid, 2-hydroxy-5-
(4'-tert-butylphenyl) -1-naphthoic acid, 3
-Hydroxy-5-cyclohexyl-2-naphthoic acid and 3-hydroxy-4- (2'-hydroxy-3'-
Carboxyphenyl) -2-naphthoic acid and the like.

Of these, preferred is 3-cyclohexyl-5-
(Α, α-Dimethylbenzene) salicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl) salicylic acid, 3
-{4 '-(α', α'-dimethylbenzyl) phenyl} -5- (α, α-dimethylbenzyl) salicylic acid,
3,5-di (α-methylbenzyl) salicylic acid, 3- (α
-Methylbenzyl) -5- (α, α-dimethylbenzyl) salicylic acid and 3,5-di (α, α-dimethylbenzyl) salicylic acid.

The particle size of the aromatic carboxylic acid type developer is usually 10 microns or less, preferably 1 to 5 microns. If there are many particles of more than 10 microns, the amount of sediment of the aqueous dispersion of the aromatic carboxylic acid type developer (hereinafter, abbreviated as an aqueous dispersion) during stationary storage increases, and the coloring performance of the pressure sensitive paper, especially immediately after coloring. Concentration decreases. On the other hand, if it is less than 1 micron, the aqueous dispersion exhibits a thickening behavior, and it becomes difficult to handle the high concentration and the aqueous dispersion.

Aromatic carboxylic acid type developer The amount of the aromatic carboxylic acid type developer in the water dispersion is usually 10 to 60%, preferably 20 to 60% based on the weight of the aromatic carboxylic acid type developer moisture. , The amount of dispersant is usually based on the weight of the aromatic carboxylic acid type developer.
It is 0.1% or more, preferably 0.5 to 20%.

When preparing pressure sensitive paper using an aqueous dispersion, inorganic pigments [kaolin, bentonite, talc, potassium carbonate, barium sulfate, aluminum oxide (alumina), silicon oxide (silica) are used to adjust the paper surface characteristics of the pressure sensitive paper. , Satin white, titanium oxide, etc.]; Pigment dispersants (phosphates such as sodium metaphosphate, sodium hexametaphosphate, sodium tripolyphosphate and polycarboxylic acids such as polyacrylic acid soda); coating binders [oxidized starch, enzymatic Modified starches such as starch, urea phosphate starch, and alkylated starch, water-soluble proteins such as casein and gelatin, styrene-butadiene latex (SBR), methyl methacrylate-butadiene latex (MBR), vinyl acetate polymer emulsion, vinyl acetate Copolymer emulsion, synthesis of polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, etc., semi-synthetic binder, etc.]; Other additives (optical brightening agent, defoaming agent, viscosity modifier, dusting inhibitor, slime control agent) , Lubricants, waterproofing agents, etc.) can be used.

If necessary, the aqueous dispersion is mixed and dispersed with the above-mentioned various components to form a color developer coating, which is then coated with an air coater, a blade coater, a brush coater, a roll coater, a bar coater, paper, synthetic paper, or a synthetic resin film. Is coated on the support of 1 above and dried to obtain a pressure-sensitive color developing sheet.

The coating amount of the coating is generally 0.5 g / m ² or more in dry weight, preferably 1 to 10 g / m ^2.

[Examples] Hereinafter, the present invention will be further described with reference to Examples, but the present invention is not limited thereto. Parts and% in the examples are by weight.

Example 1 As a sulfonation reactor, 1040 g of 1,2-dichloroethane and 9.1 g (0.05 mol) of triethyl phosphate were added to a 3 L four-necked flask equipped with a stirrer and a thermometer. Further, in advance, a copolymer of styrene and maleic anhydride (polymer A
A solution A was obtained by dissolving 101 g (0.5 mol as a styrene unit constituting the copolymer) having a molar ratio of 50/50 and a molecular weight of 10,000 in 909 g of 1,2-dichloroethane.

Keep the temperature in the reactor at 15 to 20 ℃, and add 4g of liquid anhydrous sulfuric acid.
(0.05 mol) was gradually added dropwise. Then, 10 g of solution A and 40 g of liquid anhydrous sulfuric acid (0.5 mol) were simultaneously added dropwise. The dropping rate was adjusted so that the solution A had a rate of 340 g / hour and the sulfuric anhydride had a rate of 13 g / hour. During the dropping, the temperature was kept at 18 to 22 ° C by cooling.

The sulfonated polymer A precipitated as it formed. After the completion of the sulfonation, the dispersion rally of the sulfonated polymer was gradually added to 500 g of an aqueous solution containing 22 g of sodium hydroxide at a temperature of 30 ° C. with stirring. Further, 1,2-dichloroethane was distilled off until the odor of 1,2-dichloroethane in the aqueous liquid of the sulfonate was eliminated. After adjusting the pH to 8.0 with an aqueous sodium hydroxide solution, add water and add 3
A 0% strength sodium salt of sulfonated polymer A was obtained.
The sulfonic acid content of the polymer is 28% by weight, and the viscosity of the aqueous solution is
It was 70 cps. This is the dispersant of the present invention.

Examples 2 to 4 Various polymers were reacted in the same manner as in Example 1 to obtain sulfonated sodium salts of various polymers. These are the dispersants of the present invention. The results are shown in Table-1.

Example 5 120 g of water and 180 g of isopropyl alcohol were charged into a 1,000 cc Kolben equipped with a stirring blade, a cooling tube, a dropping funnel, a nitrogen blowing tube and a thermometer, and the temperature was raised to the reflux temperature under a nitrogen stream. 100 g of water, 60 g of sodium styrenesulfonate and 40 g of methacrylic acid were charged into the dropping funnel, and 1 g of sodium persulfate and 10 g of water were charged into another dropping funnel, and each of them was simultaneously dropped into Kolben for about 2 hours. After the dropping, aging was carried out at a reflux temperature for about 2 hours.

After aging, remove isopropyl alcohol and add water.
A 30% concentration water-soluble polymer (viscosity 200 cps) was obtained. This is the dispersant of the present invention.

Examples 6 to 85 Various vinyl monomers were polymerized in the same manner as in Synthesis Example 5 to obtain various sulfonic acid (salt) group-containing polymers. These are the dispersants of the present invention.

The results are shown in Table-2.

However, the content in () indicates the sulfonic acid group content (% by weight) in the polymer.

Use Examples 1 to 8 and Comparative Use Examples 1 to 2 As a comparison with the dispersant of Examples 1 to 8, polystyrene sulfonic acid sodium salt (molecular weight: about 7,000, degree of sulfonation)
About 70%) and polystyrene sulfonic acid ammonium salt (molecular weight about 5,000, sulfonation degree about 70%) each 1 part (dry weight conversion) is dissolved in 200 parts of water, the average particle size of 1μ
Disperse 20 parts of 3,5-di (α-methylbenzyl) salicylic acid, 70 parts of aluminum hydroxide having an average particle size of 2μ, and 10 parts of zinc oxide, and add a styrene-butadiene copolymer latex (50% concentration 40 parts was added to obtain a color developer paint.
Thus the coating obtained to obtain a color-developing sheet was coated with a blade coater so as to be 5 g / m ² by dry weight to paper 40 g / m ^2. These are referred to as Use Examples 1 to 8 and Comparative Use Examples 1 and 2, respectively.

Test Example 1 Table 3 shows the test results of the performance of the above-mentioned paint and color developing sheet.
Shown in. Details of the items in the table are as follows.

1) Mechanical stability of paint 300g of paint with a solid concentration of 30% is put in a container with a diameter of 10 cm and stirred for 60 minutes at 3000 rpm using a propeller mixer, and then the viscosity is measured. At the same time, the presence or absence of agglomerate particles of the paint Was visually determined. In both cases, the measurement was performed at 20 ° C. The viscosity was measured at 60 rpm using a B type viscometer (manufactured by Tokyo Keiki Co., Ltd.).

2) Ripe stability of paint 300g of paint with a solid concentration of 30% was placed in a 500ml beaker, and the beaker was left in a water bath at 60 ° C for 60 minutes, then the temperature of the paint was cooled to 20 ° C and the viscosity was measured. At the same time, the presence or absence of agglomerated particles (spots) in the coating material was visually determined at the same time.

3) Coloring property of color developing sheet The coated paper of the commercially available pressure sensitive paper and the coating surface of the color developing sheet are made to face each other, and the quality paper is put on the top and bottom to make the color develop with an electric typewriter, and the color developability is visually judged (○ : Good, Δ: Practical level but insufficient).

[Advantages of the Invention] Since the color developer dispersion using the acid separating agent of the present invention has good stability and color developability, it is preferably used as a acid separating agent of a color developing agent for pressure-sensitive paper.

Claims (1)

[Claims] 1. A constitutional unit comprising a sulfonic acid (salt) group-containing monomer (A), a carboxylic acid (salt) group-containing monomer (B) and optionally a hydrophilic nonionic vinyl monomer (C). A dispersant for an aromatic carboxylic acid developer for pressure-sensitive paper, which comprises a water-soluble or water-dispersible polymer.