JPH0365380A - Dispersant for developer for pressure sensitive paper - Google Patents

Abstract

PURPOSE:To improve the stability and color developing property of dispersant solution by a method wherein dispersant for aromatic carboxylic acid developer for a pressure sensitive paper is prepared by water-soluble or water-dispersive polymer having the constituting units of sulfonic acid (salt) group-containing monomer, carboxylic acid (salt) group-containing monomer and hydrophilic non-ionic vinyl monomer if necessary. CONSTITUTION:Dispersant is constituted of water-soluble or water-dispersive polymer having the constituting units of sulfonic acid (salt) group-containing monomer (A), carboxylic acid (salt) group-containing monomer (B) and hydrophilic non-ionic vinyl monomer (C) if necessary. The water soluble or water-dispersive polymer may be (I); the sulfonated substance and/or the salt of the same of a copolymer having the constituting units of styrene group, (B) and (C) if necessary, (II); a copolymer having the constituting units of sulfonic acid (salt) group-containing monomer, (B) and (C) if necessary, however, (I) is preferable. The dispersing solution of developer, which employs such a dispersant, is excellent in stability and color developing property and, therefore, is employed preferably for the dispersant of the developer for a pressure sensitive paper.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a dispersant for an aromatic carboxylic acid color developer for pressure-sensitive paper.

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

[Problems to be Solved by the Invention] However, this product did not have sufficient stability or color development of the dispersion.

[Means for Solving the Problems] The present inventors have arrived at the present invention as a result of studying dispersants for aromatic carboxylic acid color developers for pressure-sensitive paper that have sufficient dispersion stability and color development. .

That is, the present invention provides a sulfonic acid (salt) group-containing monomer (A),
Aromatic carboxylic acid for pressure-sensitive paper consisting of 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 constitutional units It is a dispersant for color developers.

The water-soluble or water-dispersible polymer in the present invention is C
I) A sulfonated product of a copolymer containing styrenes, (B) and optionally (C) as a constituent unit, and/or a salt thereof, (■) a sulfonic acid (salt) group-containing monomer, (B) and necessary Examples include copolymers having (C) as a constituent unit, with (■) being preferred.

(I) A sulfonated product of a copolymer containing styrenes and (B) and, if necessary, (C) as constituent units: Styrenes include styrene, α-methylstyrene, α
- Examples include ethylstyrene.

(B) is an unsaturated carboxylic acid or its anhydride [
(meth)acrylic acid, fumaric acid, (anhydrous)maleic acid,
Examples include (anhydrous) itaconic acid, etc., and their salts. Among these, maleic anhydride and (meth)acrylic acid are preferred.

(C) is an amide group-containing vinyl monomer [(meth)acrylamide, N-methyl(meth)acrylamide, N
-Methylol (meth)acrylamide, N, N, -
Hydroxyl group-containing vinyl monomers such as dimethylacrylamide [hydroxyethyl (meth)acrylate,
Hydroxypropyl (meth)acrylate, triethylene glycol (meth)acrylate, (meth)allyl alcohol, etc.]. Among these, preferred are hydroxyl group-containing vinyl monomers.

The content of styrene in the copolymer (hereinafter abbreviated as polymer 1) containing styrene and (B) and optionally (C) as constitutional units is usually 10 to 90 mol%, preferably 30 to 90% by mole.
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 to 60 mol%.

The molecular weight of the polymer 1 is usually 500 to 11. ooo, oo
o, preferably 2,000 to 500.0001, more preferably 3. DOO~100,000.

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

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

Specific examples of aliphatic halogenated hydrocarbons include 1.2-
Dichloroethane, methylene dichloride, ethyl chloride, carbon tetrachloride, 1,1-dichloroethane,! , 1.2,2-
Examples include tetrachloroethane, chloroform, and ethylene dipromide. As nitrated aliphatic hydrocarbons,
Nitromethane, nitroethane, l-nitropropane, 2
-Nitropropane, etc. Preferred are aliphatic halogenated hydrocarbons.

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

As the sulfonating agent, sulfuric anhydride, chlorosulfuric acid, etc. are used. Preferred is sulfuric anhydride.

Liquid sulfuric anhydride, liquid sulfuric anhydride mixed with nitrogen, an inert gas such as dry air, and a solvent inert to the sulfonating agent such as an aliphatic halogenated hydrocarbon having 1 to 2 carbon atoms such as 1,2-dichloroethane or ethyl chloride. Anhydrous sulfuric acid diluted with The concentration of sulfuric anhydride diluted with inert gas is usually 1-15
% by volume, preferably 3-5% by volume. The concentration of sulfuric anhydride diluted with an inert solvent is usually 1 to 50% by weight, preferably 5 to 20% by weight.

Moreover, a complex of sulfuric anhydride and Lewis base can also be used. Examples of Lewis bases include trialkyl phosphates such as triethyl phosphate and trimethyl phosphate;
Examples include fatty acid alkyl esters such as ethyl acetate and ethyl valmitate, dioxane, thioxane, diethyl ether, and thioether. Preferred Lewis bases are trialkyl phosphates and fatty acid alkyl esters.

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

The sulfonation reaction is usually carried out at 0 to 80°C, preferably at 1
It is carried out at 0-50°C and in anhydrous conditions.

Sulfonates are typically hydroxides, carbonates, or ammonia, such as alkali metals such as sodium and potassium, alkaline earth metals such as calcium and magnesium,
It is neutralized with a neutralizing agent such as amines, such as alkylamines such as triethylamine, dimethylamine, laurylamine, and stearylamine, and alkanolamines such as monoethanolamine and jetanolamine.

Preferably sodium, potassium, and ammonium salts.

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

Patent application No. 1-1 for which the present applicant has applied for a patent for a method other than the above-mentioned method.
Sulfonation can also be carried out by the methods described in Japanese Patent Application No. 81169, Japanese Patent Application No. 1-114593, and Japanese Patent Application No. 1-117832.

(n) Copolymer containing a sulfonic acid (salt) group-containing monomer and (B) and, if necessary, (C) as constituent units: As the sulfonic acid (salt) group-containing monomer, aromatic hydrocarbon vinyl Sulfonic acid, (meth)acrylamide containing sulfonic acid group,
Examples include sulfonic acid group-containing (meth)acrylates, aliphatic hydrocarbon vinyl sulfonic acids, and salts thereof.

Specifically, the following monomers may be mentioned.

(A-1) Aromatic hydrocarbon vinyl sulfonic acid p- and 0-styrene sulfonic acid, styrene disulfonic acid, α-
Methylstyrenesulfonic acid, vinylphenylmethanesulfonic 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)acrylamido-2-hydroxypropanesulfonic acid, p-
(Meth)acrylamide methylbenzenesulfone salt (A-3) Sulfonic acid group-containing (meth)acrylate 3-
(meth)acryloyloxypropane-l-sulfonic acid,
4-(meth)acryloyloxybutane-1-sulfonic acid, 4-(meth)acryloyloxybutane-2-sulfonic acid, 2-(meth)acryloyloxyethyl-1-sulfonic acid, 3-(meth) Acryloyloxy-2-hydroxypropanesulfonic acid, etc. and their salts (A-4) Aliphatic hydrocarbon vinylsulfonic acid Vinylsulfonic acid, (meth)allylsulfonic acid, etc. and their salts As salts of sulfonic acid group-containing monomers are alkali metal salts such as sodium, potassium, and lithium, calcium,
Examples include alkaline earth metal salts such as magnesium, ammonium salts, amine salts such as ethanolamine, jetanolamine, monomethylamine, trimethylamine, and triethylamine, and preferred are sodium salts, potassium salts, and ammonium salts.

A monomer (B) that copolymerizes with a sulfonic acid (salt) group-containing monomer
) and (C) include those similar to those mentioned above.

Examples of the salt of the carboxylic acid group-containing monomer include those similar to the salts of the sulfonic acid group-containing monomer.

The content of the sulfonic acid (salt) group-containing monomer in the polymer (II) is usually 10-90 mol%, preferably 30-90 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 to BO mol%.

There are no particular restrictions on the production of the polymer (n), but
It can be produced by a normal solution polymerization method. For example, a sulfonic acid (salt) group-containing monomer and (B) and optionally (C
), water; lower alkyl alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol;
50 in a solvent such as cellosolves such as methyl cellosolve and ethyl cellosolve, or a mixed solvent of two or more of these.
Polymerize at ~150°C.

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 monomer. If necessary, a chain transfer agent such as lauryl mercaptan ethanol 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 1,000,000, more preferably 3,0
00 to 200,000. Molecular weight is N 1,00
If it is less than 0, sufficient dispersibility cannot be obtained;
If it exceeds 0.00, 000, the viscosity of the aqueous polymer liquid increases and workability decreases.

When expressed as a 30% by weight aqueous liquid viscosity, it is usually about 10 to 1
00,000 cps, preferably about 20-5G,
000cps.

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

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

As an aromatic carboxylic acid color developer, 3-phenyl-5-
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-5-7didilsalicylic acid, 3,5-di(4'
-aminophenyl)-2-aminobenzoic acid, 3-methyl-5-benzylsalicylic acid, 2-nitro-3-me, thiru-5-(4'-methylbenzoyl)benzoic 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-tert-butyl-5-(p -te
rt-butylbenzyl)salicylic acid, 3-cyclohexyl-5-(α,α-dimethylbenzyl)salicylic acid, 4
-phenyl-5-benzoylsalicylic acid, 3. s-shi (
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)benzenesulfone acid, 3-
Methyl-5-(S'-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, l-benzoyl-2-hydroxy-3-naphthoic acid, l-chloro-
4'-Hydroxy-dinaphthylketone-3'-carboxylic acid, l,4-di(dimethylamino)-3-phenyl-2
-naphthoic acid, 2-hydroxy-5-(4'-ter
t-butylph, Znyl)-1-naphthoic acid, 3-hydroxy-5-cyclohexyl-2-naphthoic acid and 3
-hydroxy-4-(2'-hydroxy-3'-carboxyphenyl)-2-naphthoic acid and the like.

Among these, preferred is 3-cyclohexyl-5-
(α, α-dimethylbenzene) salicylic acid, 3-phenyl-5-(α, α-dimethylbenzyl) salicylic acid, 3
- (4'-(α',α'-dimethylbenzylenyl)-5-(α,α-dimethylbenzyl)salicylic acid, 3
．． 5-di(α-methylbenzyl)salicylic acid, 3-(α
-methylbenzylzyl)salicylic acid and 3,5-di(α,α-dimethylbenzyl)salicylic acid.

The particle size of the aromatic carboxylic acid color developer is usually 10 microns or less, preferably in the range of 1 to 5 microns. If there are many particles exceeding 10 microns, there will be a lot of sediment when the aromatic carboxylic acid color developer aqueous dispersion (hereinafter abbreviated as aqueous dispersion) is stored stationary, and the coloring performance of the pressure-sensitive paper, especially immediately after coloring, will increase. concentration decreases. On the other hand, if it is less than i micron, the aqueous dispersion exhibits thickening behavior, making it difficult to increase the concentration and handle the aqueous dispersion.

The amount of the aromatic carboxylic acid developer in the aromatic carboxylic acid developer aqueous dispersion is usually 10 to BO%, preferably 20 to BO%, based on the weight of the aromatic carboxylic acid developer aqueous dispersion. 6
0%, the amount of dispersant is usually 0.1% or more, preferably 0.5 to 20% based on the weight of the aromatic carboxylic acid color developer.
It is.

When making pressure-sensitive paper using an aqueous dispersion, inorganic pigments such as kaolin, bentonite, talc, calcium carbonate, barium sulfate, aluminum oxide (alumina), and silicon oxide (silica) are used to adjust the paper properties of the pressure-sensitive paper. ,
Satin white, titanium oxide, etc.; Pigment dispersants (phosphates such as sodium metaphosphate, sodium hexametaphosphate, and sodium tripolyphosphate, and polycarboxylic acids such as sodium polyacrylate); Coating binders [oxidized starch, enzymatic starch , modified starches such as urea phosphate starch and alkylated starch, water-soluble proteins such as casein and gelatin, styrene-butadiene latex (SDR), methyl methacrylate-butadiene latex (MBR), vinyl acetate polymer emulsion, acetic acid Synthetic and semi-synthetic binders such as vinyl ethylene copolymer emulsilone, polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, and methyl cellulose; Other additives (
Optical brighteners, antifoaming agents, viscosity modifiers, anti-dusting agents, slime control agents, lubricants, waterproofing agents, etc.) can be used.

If necessary, the aqueous dispersion is mixed and dispersed with the above-mentioned various components to make a color developer paint, and this is coated on a support such as paper, synthetic paper, or synthetic resin film using an air knife coater, blade coater, brush coater, roll coater, or bar coater. It is applied and dried to make a color developing sheet for pressure-sensitive paper.

The amount of paint to be applied is usually 0.5 g/- or more, preferably 1-10 g/dry weight.

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

Example 1 As a sulfonation reactor, 1,2-dichloroethane 1 was placed in a 3 L four-necked flask equipped with a stirrer and a thermometer.
040 g and triethyl phosphate 9.1 g (0,05
mol) was added. In addition, in advance, 101 g of a copolymer of styrene and maleic anhydride (referred to as polymer A; molar ratio 50,150, molecular weight 10,000) (0.5 mol as styrene units constituting the copolymer) was mixed with 1.2-dichloroethane. Solution A was obtained by dissolving in 909 g.

The temperature in the reactor was maintained at 15-20°C, and 4 g (0.05 mol) of liquid sulfuric anhydride was gradually added dropwise. Next, 010 g of solution Al and 40 g (0.5 mol) of liquid sulfuric anhydride were simultaneously added dropwise. The dropping rate was 340g of solution A.
/hour, and sulfuric anhydride was adjusted to a rate of 13g/hour. During the dropping, the temperature was maintained at 18-22°C by cooling.

Sulfonated Polymer A precipitated as it formed. After the sulfonation was completed, the dispersion slurry 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. while stirring.

Furthermore, until the odor of 1,2-dichloroethane in the aqueous solution of the sulfonate disappears! , 2-dichloroethane was removed by distillation. After adjusting pna, o with an aqueous sodium hydroxide solution, water was added to obtain a sodium salt of sulfone specific polymer A with a concentration of 30%.

The sulfonic acid content of the polymer was 28% by weight, and the viscosity of the aqueous solution was 70 cps. This is used as the dispersant of the present invention.

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

Table 1 Example 5 Water was added to a 1,000cc Kolben equipped with a stirring blade, a cooling pipe, a dropping funnel, a nitrogen blowing pipe, and a thermometer.
0 g and 180 g of isopropyl alcohol were charged, and the temperature was raised to reflux temperature under a nitrogen stream. A dropping funnel was charged with 100 g of water, 60 g of sodium styrene sulfonate, and 40 g of methacrylic acid, and a separate dropping funnel was charged with 1 g of sodium persulfate and log water, and each was simultaneously dropped into the Kolben over about 2 hours.

Aging was carried out at reflux temperature for about 2 hours.

After aging, the isopropyl alcohol was distilled off and water was added to obtain a water-soluble polymer with a concentration of 30% (viscosity 200 cps). This is used as the dispersant of the present invention.

Examples 6 to 8 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 used as the dispersants of the present invention.

The results are shown in Table-2.

Table 2 The values in parentheses () indicate the content of sulfonic acid groups (% by weight) in the polymer.

Use Examples 1 to 8, Comparative Use Examples 1 to 2 The dispersants of Examples 1 to 8 and, for comparison, polystyrene sulfonate sodium salt (molecular weight approximately 7000, degree of sulfonation approximately 70%), polystyrene sulfonate ammonium salt (molecular weight approximately 70%) 5000. Degree of sulfonation approximately 70
%) in 200 parts of water, 20 parts of 3.5-di(α-methylbenzyl)salicylic acid with an average particle size of lμ, and 70 parts of aluminum hydroxide with an average particle size of 2μ. , 10 parts of zinc oxide was dispersed, and styrene-butadiene copolymer latex (50% concentration) was added to the dispersion.
A developer paint was obtained by adding 40 parts of .

The paint thus obtained was applied to a 40 g/m'' paper with a blade coater to give a dry weight of 5 g/a'' to obtain a color developing sheet. Use each of these in example 1~
8. Comparative usage examples 1 and 2.

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

l) Mechanical stability of paint 300 g of paint with a solid concentration of 30% is placed in a container with a diameter of 10 cm, and after stirring at 30 GO rpm for 80 minutes using a propeller mixer, the viscosity is measured, and at the same time, the presence or absence of agglomerated particles of the paint is determined. was determined visually. Both measurements are 20°
I went with C. The viscosity was measured using a B-type viscometer (manufactured by Tokyo Keiki Co., Ltd.) using a BOrl 11.

2) Thermal stability of paint 300 g of paint with a solid concentration of 30% was placed in a 50 hl beaker, and the beaker was placed in a water bath at 60°C for 60 ml.
After standing for a minute, the temperature of the paint was cooled to 20° C. and the viscosity was measured, and at the same time, the presence or absence of agglomerated particles (bubbles) in the paint was visually determined.

3) Color development property of the color developer sheet The top sheet of commercially available pressure-sensitive paper and the coated side of the color developer sheet were placed opposite each other, and high-quality paper was placed above and below, and color was developed using an electric typewriter, and the color development property was visually judged ( o: Good, Δ: Practical level but insufficient).

Table-3 Test results [Effects of invention

Claims (1)

[Claims] 1. A water-soluble product whose constituent units are 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 color developer for pressure-sensitive paper made of a water-dispersible polymer.