JPH01111438A - Aqueous suspension - Google Patents

Abstract

PURPOSE:To enhance stability in long-term storage by dispersing in water a compound of a specific salicylic acid resin with a polyvalent metal in the presence of, for example, a polyvinyl alcohol derivative having a sulfonic group in the molecule. CONSTITUTION:A salicylic acid derivative is provided which consists of 5-40mol.% structural units represented by formula I (wherein R1 and R2 represent H or a methyl group, and R3 represents H or a 1-4C alkyl group), and 60-95mol.% structural units represented by formula II (wherein R1, R2 and R3 are as defined above), and which has a weight-average mol. wt. of from 500-10,000. Subsequently, this salicylic acid derivative is dispersed in water together with an anionic water-soluble polymer which is a polyvinyl alcohol derivative having a sulfonic group in the molecule or a salt thereof, or together with a similar compound, thereby preparing an aqueous suspension of a compound of a salicylic acid resin with a polyvalent metal. This aqueous suspension does not suffer from sedimentation or flocculation even if it is stored for a prolong period of time, and further it shows improved long-term stability especially at high temperatures.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides an aqueous suspension of a polyvalent metal compound of a salicylic acid resin having a novel composition, particularly a novel oil-soluble salicylic acid suspension used as a material for pressure-sensitive copying paper. The present invention relates to an aqueous suspension of a resin polyvalent metal compound.

More specifically, the present invention relates to an aqueous suspension of a polyvalent metal compound of a salicylic acid resin for pressure-sensitive copying paper, which has significantly improved hue, storage stability of the dispersion, and dispersion stability of a paint for coating base paper.

(Prior Art) Generally, pressure-sensitive copying paper consists of a sheet (CB paper) coated with microcapsules of a non-volatile organic solvent containing an electron-donating organic compound (so-called pressure-sensitive dye), and an electron-accepting color developer. A water-based paint composition containing an agent) (
CF paper), with each coated side facing the other, and the microcapsules are destroyed by the printing pressure of a ballpoint pen, typewriter, etc., and the pressure-sensitive dye solution that flows out is brought into contact with a color developer and colored. This is what I did. Therefore, by changing the combination of the microcapsule layer containing the pressure-sensitive dye and the color developer layer, it is possible to make multiple copies, and it is also possible to produce pressure-sensitive copying paper (SC paper) that develops color with a single sheet. It is possible.

Colorless or monochromatic dye precursors used in such pressure-sensitive copying papers include (1) triarylmethane phthalide compounds such as crystal violet lactone, (2) 3-dibutylamino-6-methyl-7- One or more selected from fluoran compounds such as anilinofluorane (3) pyridyl phthalide compounds (4) fetchazi compounds (5) leucoauramine compounds, etc. are dissolved in a hydrophobic high-boiling solvent. and microencapsulated.

used.

On the other hand, electron-accepting color developers have conventionally been used as (1) inorganic solid acids such as acid clay and activated clay, (2) oil-soluble phenol/formaldehyde condensates and their polyvalent metal modified products, or (3) substituted salicylic acids. polyvalent metal salts are used. However, these color developers lack image stability, resulting in colored images changing and fading during storage, and insufficient water resistance stability or solvent resistance stability.

The present inventors discovered a new polyvalent metal compound of salicylic acid resin as a color developer that solved these problems, and filed a patent application for the same (Japanese Patent Application No. 201831/1983).

Generally, in order to produce pressure-sensitive copying paper using a color developer, the developer is wet coarsely pulverized in the presence of a surfactant, and the particle size is 1.
A dispersing agent is used to form an aqueous suspension into fine particles of ~10 scales.

[Problem that the invention seeks to solve]

However, the selection of a combination of particles to be dispersed and a dispersant to obtain a good dispersion system is mostly based on experience, and there is no law of crotch. Furthermore, when selecting a dispersant, it is necessary to consider not only the dispersibility but also the influence it has on the action of the particles to be dispersed.

Therefore, it is not easy to combine the polyvalent metallized salicylic acid resin and a dispersant compatible with it to create an aqueous suspension that has good performance in various aspects such as dispersibility, stability, and color development. do not have. That is, P-phenylphenol formaldehyde polymers and P-octylphenol formaldehyde polymers currently used as color developers for pressure-sensitive copying paper usually contain polycarboxylic acid type anionic polymeric surfactants, specifically, The sodium salt of diisobutylene maleic anhydride copolymer is used as a dispersant, but when these are used as a dispersant to form an aqueous suspension of the polyvalent metal compound of the salicylic acid resin, polyvalent metals and carboxyl Unfavorable complex formations occur with acid salts. As a result, dispersion performance and dispersion stability are significantly reduced, foams that are difficult to defoam are formed, and the physical properties of the color developer are changed due to deterioration of the polyvalent metal compound of the salicylic acid resin, which is the substance to be dispersed, so that it cannot be put to practical use. It is not possible to obtain an aqueous suspension.

In addition, some salts of formaldehyde condensates of naphthalene sulfonic acid and salts of lignin sulfonic acid, which were once used in phenol formaldehyde condensate color developers, have dispersibility for the polyvalent metal compound of the salicylic acid resin. When used in pressure-sensitive copying paper, it is extremely impractical due to the dispersant itself causing discoloration of the paper surface or photoyellowing.

The present invention has been made to solve the above problems, and its first main purpose is to provide excellent dispersibility, stability, etc., which is extremely convenient when manufacturing pressure-sensitive copying paper. The objective is to provide an aqueous suspension that can be used for The second
is an aqueous suspension that enables the production of high-quality pressure-sensitive copying paper that has high image stability, water resistance stability, and solvent resistance stability, and that does not cause discoloration or yellowing of the paper surface or discoloration of the colored image during storage. The objective is to provide a cloudy liquid.

[Means for solving problems]

The above objects can be achieved by the present invention as described below. That is, the present invention provides the following: (wherein R,, R2 represents a hydrogen atom or a methyl group, and R
1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ), the structural unit (I) is 5 to
40 mol%, the structural unit (II) is 60 to 95 mol%, the structural unit (I) is bonded to the structural unit (■-), and the weight average molecular weight is 500 to 10,000. (A) an anionic water-soluble polymer consisting of a polyvinyl alcohol derivative or a salt thereof having a sulfonic acid group in the molecule and/or (
[1] A homopolymer or copolymer containing as an essential component a compound represented by the general formula (m) (wherein R is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and M is an alkali metal or ammonium ion) This is an aqueous suspension of a polyvalent metal compound of salicylic acid resin dispersed in the presence of an anionic water-soluble polymer consisting of:

The aqueous suspension of the present invention is made by aqueous suspension of a polyvalent metallized salicylic acid resin having good color development performance using a dispersant that is particularly compatible with the metallized product and has excellent properties. It can be suitably used in the production of pressure-sensitive copying paper,
Moreover, the pressure-sensitive copying paper produced thereby also exhibits improved coloring performance and other properties.

The present invention will be explained in more detail below.

First, in the present invention, (A), (
It) refers to the anionic water-soluble polymer.

The anionic water-soluble polymer (A) is an anionic water-soluble polymer made of a polyvinyl alcohol derivative or a salt thereof having a sulfonic acid group in the molecule, and its degree of polymerization is 200 to 5000, preferably 300. ~2000
It is.

In addition, in group (A) polymers, the sulfonic acid group is generally an alkali metal (Na", K", Li", Cs",
Rh”.

Fr”) or NH,” salt.

The method for producing the anionic water-soluble polymer (A) is as follows: (1) Vinyl acetate and α containing a sulfonic acid group in the molecule.
- Method of obtaining by copolymerization with β-unsaturated monomer and saponification (2) Method of reacting polyvinyl alcohol with concentrated sulfuric acid (3) Method of oxidizing polyvinyl alcohol with bromine, iodine, etc. and then reacting with acidic sodium sulfite (4) Examples include a method in which an aldehyde compound having a sulfone group is reacted with polyvinyl alcohol in the presence of an acid catalyst to form a sulfoacetal.

Among these, method (1) is preferred.

Specific examples of α,β-unsaturated monomers having sulfonic acid groups include (1) sulfoalkyl acrylates, such as sulfoethyl acrylate, sulfoethyl methacrylate (2) vinylsulfonic acid, styrenesulfonic acid, allylsulfonic acid (3) ) maleimido-N-alkanesulfonic acid, (4
) 2-acrylamido-2-methylpropanesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, etc. are exemplified, and generally 0.0.
After copolymerizing at a ratio of 5 to 20 moles, preferably 1 to 10 moles, the vinyl acetate group can be obtained by saponification (50 to 100!K) under alkaline conditions by a conventional method.

The anionic water-soluble polymer (A) can be obtained by sulfonating vinyl acetate and an aromatic α,β-unsaturated polymer such as styrene, followed by saponification. Vinyl and α, β containing sulfonic acid groups in the molecule
Other than -unsaturated unsaturated polymers, α,β-unsaturated unsaturated metal polymers can also be obtained by combining them, and these are also included as the anionic water-soluble polymer of (A).

A typical example of the anionic water-soluble polymer (B) represented by the above formula is a polymer having styrene sulfonic acid or a derivative unit thereof in the molecule.

Among these, preferred examples include polystyrene sulfonate and polyα-methylstyrene sulfonate having an average degree of polymerization of 5 to 10,000.

Such a homopolymer may be synthesized in any way. That is, a salt of a polystyrene sulfonic acid derivative may be synthesized by sulfonating polystyrene, or may be synthesized by polymerizing styrene sulfonic acid (or a salt thereof).

Polymerization may be carried out by known methods. For example, radical polymerization and ionic polymerization at 0 to 150°C.

Specific examples of the anionic water-soluble polymer (B) being a copolymer include a salt of a copolymer of styrene sulfonic acid and maleic anhydride, a sulfonated salt of a styrene maleic acid copolymer, and a salt of a sulfonated product of styrene sulfonic acid and other copolymers. Examples include salts of copolymers of vinylic compounds, and salts of sulfonated copolymers of styrene and other vinyl finishing materials.

Although these may be synthesized in any manner, they can be synthesized by conventional methods such as ionic polymerization and radical polymerization.

The properties of the polymers (A) and (B) used as dispersants in the present invention are as follows.

The anionic water-soluble polymer (A) having a sulfonic acid group has a high solubility in water, is easily soluble, and has a wide range of The viscosity changes little over the pl+ range and is virtually colorless or very light colored. Therefore, it does not color the aqueous suspension of polyvalent metallized salicylic acid resin obtained using it, and therefore does not color the pressure-sensitive copying paper (CF paper) produced using the aqueous suspension. Polyvinyl alcohol derivatives with sulfonic acid groups in their molecules have the property of not deteriorating or discoloring themselves under harsh environmental conditions, but also have excellent dispersion performance for polyvalent metallized salicylic acid resins. The present invention provides a thermally, mechanically, and chemically stable aqueous suspension of a salicylic acid resin polyvalent metal compound.

Furthermore, the anionic water-soluble polymer (A) used as a dispersant in the present invention is a commonly used fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, or polyvinyl alcohol modified with carboxyl groups, etc. Unlike other products, it has low foaming properties and excellent self-defoaming properties, so it can eliminate problems caused by foam during dispersion work.

Further, the anionic water-soluble polymer (B) used in the present invention also provides a stable aqueous solution over a wide pH range and is extremely light in color.

In this way, in the present invention,
The water-soluble anionic polymers (A) and (B) each have extremely excellent dispersion ability for polyvalent metallized salicylic acid resins, and the aqueous suspension of the present invention has a high concentration, low viscosity, and stability. Become something. Furthermore, problems such as significant foaming or difficulty in defoaming, which occur when ordinary polyvinyl alcohol is used, do not occur.

In addition, the anionic water-soluble polymer (A) used in the present invention is not only anionic but also nonionic, and has excellent dispersion performance as well as excellent protective colloid ability. It has significantly better mechanical and thermal stability than aqueous suspensions using other dispersants.

The salicylic acid resin polyvalent metal compound used in the present invention will be explained next.

The polyvalent metallized salicylic acid resin used in the present invention has the structure described above, and the metals include metals other than alkali metals such as lithium, sodium, and potassium. Preferred polyvalent metals include calcium,
Examples include magnesium, aluminum, copper, zinc, tin, barium, cobalt and nickel. Among these, zinc is particularly effective.

The polyvalent metallized salicylic acid resin used in the present invention can be produced, for example, as follows.

That is, first, salicylic acid esters represented by the general formula (rV) (wherein R4 represents an alkyl group, an aralkyl group, an aryl group, or a cycloalkyl group having 1 to 12 carbon atoms) are converted into salicylic acid esters represented by the general formula (rV) (in the formula,
The styrene derivative represented by R1,1 (2 and R3 are already mentioned) is reacted with a free sol fluorine in the presence of a strong acid catalyst (hereinafter referred to as the first reaction), and then the obtained resin composition is hydrated. Decomposition 1 (hereinafter referred to as second-stage reaction), and the resin composition after hydrolysis is further reacted with a polyvalent metal salt (hereinafter referred to as third-stage reaction) to produce.

The salicylic acid resin produced in the first and second stage reactions is
This resin is not a known resin, but one newly discovered by the present inventors. In other words, polyvalent metallized salicylic acid resins are obtained by a method different from conventional methods. When salicylic acid esters are sequentially reacted with styrene derivatives in the presence of a strong acid catalyst, the α-position of the styrene derivative becomes a hydroxyl group of the salicylic acid skeleton. On the other hand, it was found that the excess styrene reacted to the ortho and/or para positions, and furthermore, the excess styrene reacted to the benzene ring of the styrene derivative bonded to the salicylic acid skeleton, resulting in an increase in molecular weight. This results in a useful and novel co-condensation resin.

The salicylic acid esters used in this first stage reaction include methyl salicylate, ethyl salicylate, n-propyl salicylate, isopropyl salicylate, n-butyl salicylate, isbutyl salicylate, tert-butyl salicylate, isoamyl salicylate, and salicylic acid. Examples include, but are not limited to, -tert-octyl, nonyl salicylate, dodecyl salicylate, cyclohexyl salicylate, phenyl salicylate, benzyl salicylate, and -α-methylbenzyl salicylate. Industrially preferred is methyl salicylate, which is inexpensive.

Next, the styrene derivatives defined by the general formula (V) used in this reaction include styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, 0-methylstyrene,
-ethylstyrene, p-ethylstyrene, O-isopro and Rustyrene, m-isopro and Rustyrene, p-isopropylstyrene, p-tert-butylstyrene, α-methylstyrene, β-methylstyrene, etc.
It is not limited to these. Industrially preferred is styrene, which is inexpensive.

The amount of the styrene derivative used is 1 to 20 molar ratio, preferably 2 to 10 molar ratio to the salicylic acid ester, and the average molecular weight of the resin is in the range of 500 to 10,000.

A strong acid catalyst is used in this first stage reaction.

For example, mineral acids such as hydrochloric acid, sulfuric acid, phosphoric acid, ferric chloride,
Free sol fluorocarbon catalysts such as zinc chloride, aluminum chloride, stannic chloride, titanium tetrachloride, boron trifluoride, or strong acid catalysts such as methanesulfonic acid and trifluoromethanesulfonic acid can be used. Among these, particularly preferred is sulfuric acid, which is inexpensive. The amount of the catalyst to be used is in the range of 0.05 to 200% by weight, preferably 1 to ioo% by weight based on the total weight of the salicylic acid ester and the styrene derivative.

Further, a solvent may be used in this first stage reaction. This solvent may be inert to the reaction, such as Gf, n-
Aliphatic hydrocarbons such as hexane, n-hebutane, n-pentane, and cyclohexane, ethers such as ethyl ether and ethylene glycol dimethyl ether, esters such as ethyl acetate and butyl acetate, methylene chloride, 1.2-
Halogenated hydrocarbon solvents such as dichloroethane, 1,1,2-trichloroethane, carbon tetrachloride, chloroform, and monochlorobenzene; organic acids such as acetic acid and propionic acid;
Examples include ketones such as acetone and methyl ethyl ketone, benzene carbon disulfide, nitromethane, acetonitrile, and tetrahydrofuran.

The amount of these solvents to be used is desirably 30 times the total weight of the raw materials in consideration of economy.

The reaction temperature when carrying out the first stage method is -20 °C to 1
The temperature is 80°C, preferably in the range of 0 to 120°C. Reaction time is 1 to 30 hours.

A common method for conducting the first stage reaction is to charge a catalyst into a salicylic acid ester and its organic solvent solution, and to react at a predetermined temperature while dropping the other raw material, a styrene derivative.

At this time, the dropping time is preferably 50% or more of the total reaction time, and is usually 1 to 20 hours. After the reaction, if the solvent used is insoluble in water, water may be added, washed and separated in two layers, and then the solvent may be distilled off to obtain the resin. If the solvent is soluble in water, the resin may be obtained. A precipitated resin can be obtained by charging the resin.

The salicylic acid ester strong polymer resin obtained in the first stage reaction is hydrolyzed in the second stage reaction, which may be carried out using an acid or alkaline aqueous solution.

Hydrolysis methods using acids include mineral acids such as hydrochloric acid and sulfuric acid, a combination of mineral acids and organic acids such as sulfuric acid and acetic acid, and organic acids such as benzenesulfonic acid, p-toluenesulfonic acid, chlorobenzenesulfonic acid, and methanesulfonic acid. Sulfonic acids, Lewis acids such as aluminum chloride, zinc chloride, tin chloride, as well as trifluoromethanesulfonic acid, Nafio
This is carried out using a super strong acid such as nH (DuPont Co., trade name) and water. As a hydrolysis method using an alkali, a method using caustic soda, caustic potassium and water is generally used.

When carrying out the hydrolysis reaction using these acids or alkalis, the ratio of acid or alkali to water can be selected as desired, but is usually 1:100 to 99:l, preferably 5:95.
-95:5 (weight ratio).

In addition, the amount of acid or alkali to be used with respect to the salicylic acid ester cocondensation resin obtained in the first stage reaction may be any ratio in the case of acid, but usually the amount is 0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000050055 2.3500 10.055, we5.000,000.000.0001
It is carried out in a range of 0.5 to 30 times the molar amount. In the case of alkaline,
The amount ranges from an equivalent to 30 times the molar amount relative to the raw material salicylic acid ester.

The reaction temperature is in the range of 50 to 200°C, preferably 80 to 1
It is in the range of 60°C. When conducting at high temperatures, it is carried out under naturally occurring pressure in an autoclave, but the pressure range is O~
It is 30 atm. Reaction times range from 1 to 50 hours. Quaternary ammonium salts, quaternary phosphonium salts, crown ethers, cryptates,
A phase transfer catalyst such as polyethylene glycols may be added as a reaction promoter.

Further, the second stage reaction is usually carried out without a solvent, but a solvent may be used. Examples of this solvent include N-methylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, sulfolane, 1
．． Aprotic polar solvents such as 3-dimethyl-2-imidazolidinone, N-methylpyrrolidone, hexamethylphosphotriamide, ethylene glycol, polyethylene glycol dialkyl ether, 2-methoxyethanol,
Glycols such as 2-ethoxyethal can be used, and in addition, toluene, xylene, monochlorobenzene, l, 2-
Water-immiscible solvents such as dichloroethane and 1,1,2-trichloroethane can also be used. The amount of this solvent used is
0.5 to IO volume/weight times the raw material is sufficient.

After the reaction is completed, the desired product can be obtained from the reaction solution by a general method, that is, by liquid separation, dilution, concentration, etc., to obtain the hydrolyzed resin.

As described above, several known methods, such as methods (1) to (3), can be used for the third stage reaction to obtain a salicylic acid resin polyvalent metal compound from the salicylic acid resin composition obtained by hydrolysis. can.

(1) By reacting an alkali metal hydroxide, carbonate, alkoxide, etc. with a resin, alkali metal salts of the resin or their aqueous alcohol solutions, or water-
After obtaining the alcohol mixed solution, add 0 of the water-soluble polyvalent metal salt.
A method of producing by reacting at ~100°C. In this case, it is desirable to react about 0.5 to 1 gram equivalent of water-soluble polyvalent metal salt to 1 mole of salicylic acid in the resin at 0 to 100°C.

(2) A method of mixing a resin and a polyvalent metal salt of an organic carboxylic acid such as formic acid, acetic acid, propionic acid, valeric acid, caproic acid, stearic acid or benzoic acid, and heating and melting the mixture. Optionally, further basic substances, such as ammonium carbonate,
Ammonium bicarbonate, ammonium acetate, and ammonium benzoate may be added and heated to cause a melting reaction.

(3) Basic substances such as ammonium formate, ammonium acetate, ammonium caproate, ammonium stearate, ammonium benzoate, and other organic carboxylates using resin and polyvalent metal carbonates, oxides, and hydroxides. and heating, melting, and cooling methods. The melting temperature is usually 1
The reaction time is about 1 to several hours. In addition, the polyvalent metal salt contains 1 metal to the total weight of the resin.
Preferably, it is present in an amount of 20% to 20% by weight.

The polyvalent metallized salicylic acid resin used in the present invention, which can be produced as described above, has the following disadvantages as a color developer of conventionally known aromatic carboxylic acid metal salts: (a) Colorless color development. It is possible to improve the problems such as (b) the lack of compatibility with the nonvolatile oil in which the dye is dissolved, (c) the dissolution in water, (c) the disappearance of the colored image by light, and (ii) the high cost. That is, when the polyvalent metallized salicylic acid functions as a color developer, it has excellent compatibility with the oil in the microcapsules of the upper paper, and the rate of color development at low temperatures is significantly improved compared to conventional products. , there is no solubility in water. Therefore, the color development property at low temperatures, the stability of the color image against light and water, the durability, etc. are improved, and it is an inexpensive and useful color developer.

Next, a method for preparing the aqueous suspension of the present invention from the anionic water-soluble polymers (A) and (Il) above and the polyvalent metallized salicylic acid resin will be described.

Both of the anionic water-soluble polymers (A) and (B) are generally obtained as a white powder that is easily soluble in water or as an aqueous solution, so if necessary, they are dissolved in water in advance. Then, the pH is adjusted to a range of 4 to 10, preferably 6 to 9.

Powder of salicylic acid resin polyvalent metal compound was charged into the polymer aqueous solution prepared in this way, and after stirring to form a slurry,
The average particle size is 1 to 20 JJ using a wet pulverization device, such as a ball mill, an attritor, a sand grinder, etc., which performs wet pulverization using a spherical pulverization measure.
Wet milling in J to obtain an aqueous suspension. Such wet pulverization can be performed in either a batch method or a continuous processing method, and the work is completed after pulverization to the desired particle size.

If the polyvalent metal compound of salicylic acid resin has a low softening point and easily liquefies below the boiling point of water, emulsify the polyvalent metal compound of salicylic acid resin in water by stirring at high speed in warm to hot water. It can be cooled to obtain an aqueous suspension.

In the aqueous suspension of the present invention, (A) and/or (
The amount of the anionic water-soluble polymer used in B) varies depending on the substance to be dispersed (salicylic acid resin polyvalent metal compound) and the physical properties of the intended aqueous suspension (concentration, particle size of the substance to be dispersed, etc.) and is not particularly limited. However, in order to obtain a practical aqueous suspension (average particle size of 1 to 10 units), at least 0.5 parts by weight, preferably 2 to 20 parts by weight, per 100 parts by weight of the salicylic acid resin polyvalent metal compound. Department. Note that the content of the salicylic acid resin polyvalent metal salt/aqueous suspension is preferably 30 to 60% by weight.

As the dispersant used in the present invention, either polymer (A) or (B) may be used, but it is preferable to use them in combination. By using both together, it is possible to reduce the amount of dispersant required when creating an aqueous suspension.
A more stable aqueous suspension of the salicylic acid resin polyvalent metal salt can be obtained than when used alone.

When the anionic water-soluble polymers (A) and (B) are used together, an extremely stable aqueous suspension can be obtained with 10 parts by weight or less. Additionally, other anionic and/or nonionic surfactants or water-soluble polymers may be used in combination to adjust the viscosity-rheological properties of the aqueous suspension.

The average particle size of the polyvalent metallized salicylic acid resin in the aqueous suspension is 10 microns or less, preferably in the range of 0.5 to 5 microns. If there are many particles larger than 10 microns, there will be a lot of sediment when the aqueous suspension is stored stationary, and the coloring performance of the pressure-sensitive copying paper, especially the density immediately after coloring, will be reduced.

On the other hand, below 1 micron, the aqueous suspension exhibits thickening behavior, making it difficult to increase the concentration and handle the aqueous suspension.

When producing pressure-sensitive copying paper using the aqueous suspension of the present invention prepared as described above, first, in order to adjust the paper surface characteristics of the pressure-sensitive copying paper, (1) inorganic or organic pigments, (2) pigment dispersant, (3) coating binder,
(4) Mix other various additives to prepare a water-based paint according to the coating method. This water-based paint is then applied to base paper and dried to produce pressure-sensitive copying paper.

(1) Inorganic or organic pigments used here include kaolin, calcined kaolin, bentonite, talc, calcium carbonate, barium sulfate, aluminum oxide (alumina), silicon oxide (silica), satin white, titanium oxide, polystyrene emulsion, etc. However, (2) as a pigment dispersant, phosphates such as sodium metaphosphate, sodium hexametaphosphate, and sodium tripolyphosphate, and polycarboxylate salts such as sodium polyacrylate are used (3).
) Coating binders include modified starches such as oxidized starch, enzymatic starch, urea phosphate starch, and alkylated starch, water-soluble proteins such as casein and gelatin, styrene-butadiene latex (SBR), and methyl methacrylate. Butadiene latex (MBR)
(4) Various other additives include fluorescent brighteners, antifoaming agents, Viscosity modifiers, anti-dusting agents, lubricants, waterproofing agents, etc. are used.

The water-based paint prepared by mixing and dispersing the water-soluble suspension of the polyvalent metal compound of the salicylic acid resin of the present invention and the various components described above can be used with an air knife coater, a blade coater, a brush coater, a roll coater, a bar coater, a gravure coater, etc. It is coated onto base paper and dried to form a pressure-sensitive copying paper developing sheet.

Generally, the coating amount of water-based paint is 0.5 g/rn or more on dry weight, preferably 1 to 10 g/rn''.The coloring performance of the sheet coated with water-based paint mainly depends on the salicylic acid resin polyvalent metal 10g/
A coating amount of m'' or more is not effective in improving coloring performance and is also economically disadvantageous.

The suitability of the aqueous suspension of the present invention for the production of pressure-sensitive copying paper is specifically recognized in the following points. For example, since the aqueous suspension of the present invention has little tendency to increase in viscosity, it significantly improves workability when applying aqueous paints containing it as a main component. Furthermore, if an air knife coating method using a low-viscosity coating liquid is used for coating the water-based paint, foaming during circulation of the water-based paint can be significantly suppressed, which is advantageous.

The aqueous suspension of the present invention may also be used in preparing the aqueous coating for use in pressure-sensitive copying paper.
For example, there is no tendency for thickening (shock) when mixed with white inorganic pigments such as kaolin clay and aluminum carbonate. Furthermore, the water-based suspension liquid has a high solid content and excellent thermal stability, and the water-based paints using it have excellent thermal and mechanical stability. It can be suitably applied to a coating machine that uses a water-repellent paint.

Furthermore, the novel color developer sheet for pressure-sensitive copying paper produced using the aqueous suspension of the present invention has a lower color developer sheet than a color developer sheet using an inorganic solid acid or p-phenylphenol novolak resin. It has the same or better color development properties, has significantly improved yellowing resistance due to sunlight exposure, and has advantages such as being extremely convenient for handling and storage.

[Effects of the Invention] As explained in detail above, the aqueous suspension of the present invention: - does not cause sedimentation or aggregation even when stored for a long period of time, and is stable even when stored for a long period of time, especially at high temperatures; , and has a high solids content, and when mixed with other ingredients to obtain an aqueous coating liquid, the aqueous coating liquid has excellent coating suitability (rheological properties), heat resistance, and mechanical stability, and can be easily applied.・High whiteness (less coloring) and therefore highly white, and comparable to pressure-sensitive copying paper using p-phenylphenol novolak resin, for example. It enables the production of pressure-sensitive copying paper with excellent commercial value, such as having a color development property of 1.5 or more, and ・The paper does not change its color upon exposure to light or during storage, and has significantly reduced yellowing resistance. This makes it possible to produce pressure-sensitive copying paper that is extremely convenient for handling and storage.
Work is carried out in a wide pH range, and foaming occurs during atomization.
Thickening does not reduce workability.

〔Example〕

Hereinafter, the present invention will be specifically described in detail with reference to Examples and Comparative Examples.

The performances of the aqueous suspensions, water-based paints, and pressure-sensitive copying papers obtained in Examples and Comparative Examples are summarized in Table 1.

Various performance test methods are shown below.

A) Performance of Aqueous Suspensions (I) Hue The aqueous suspension was coated on a Mayer bar with a dry weight of 5
g/rn'' (aqueous suspension coated sheets), and measure the reflectance using a blue filter using a TSS type Hunter colorimeter (manufactured by Toyo Seiki).Aqueous suspension The whiteness (whiteness) of the liquid-coated sheet is expressed as reflectance (A).

The higher the reflectance (A), the whiter the aqueous suspension;
If the difference is about 1 point (%), it is possible to discern the superiority or inferiority of f with the naked eye.

(II) Viscosity The aqueous suspension obtained by atomization was measured at 25°C using a B-type viscometer, N
The viscosity is measured under the conditions of o10-tar and 60 rpm (unit: cp).

(III) 2 kg of high temperature storage stable aqueous suspension was charged into a stainless steel beaker with an internal volume of 2 ft, and a glass stirring blade (Ikari type, diameter 100 mm) was charged.
) The sample was stored at 40° C. for one week while stirring at 1100 rpm, and the filterability before and after storage was compared in terms of filtration time (sec) through a 200-mesh sieve with a diameter of 7.5 cm. In a dispersion liquid with poor high-temperature storage stability, salicylic acid resin polyvalent metal compound particles condense and fuse in the aqueous suspension, and the sieve filtration performance decreases as the particle size grows.

B) Performance of aqueous coating liquid Using the aqueous suspensions of Examples and Comparative Examples, an aqueous coating liquid for pressure-sensitive copying paper blade coating (50% solids) having the following composition was prepared and its performance was evaluated. was measured.

Composition Solid weight parts (a) Aqueous suspension (as polyvalent metallized salicylic acid resin in liquid) 18 (b) Light calcium carbonate 100 (C) Styrene butadiene latex 6 (d) Oxidized starch
6 (e) Sodium polyacrylate (pigment dispersant) 0.5 (I) Viscosity Check for thickening using a B-type accuracy system (No. 30-ter, 60 rpm). Preferred viscosity is 300-1000 cps
It is.゛(rl) Mechanical stability -639 according to JIS using the above 50% solids water-based coating liquid
2 (Test method for NBR synthetic latex), the amount of aggregates produced was measured using a Maron mechanical stability tester,
Used as a measure of mechanical stability of water-based paints.

Measurement conditions: sample 100g, test condition 11000r
p, 10 m1n, load 20, g0 test, filter through a 200 mesh sieve, and weigh the amount of aggregates (after bone drying).

The display is expressed in terms of aggregate production rate (%).

Aqueous coating liquids that show a large aggregate production rate according to this test method may cause coating troubles due to dispersion, failure, and aggregation of the aqueous coating liquid during high-speed coating where strong shearing force is applied during coating such as blade coating or gate roll coating. It's easy to do.

C) Performance as pressure-sensitive copying paper Water-based paint that has undergone the mechanical and thermal stability tests using the homomixer described in the previous section is applied to high-quality paper in a dry coating amount of 6 g.
/d by coating with a Mayer bar and drying to obtain a biplane type pressure-sensitive copying paper developer sheet.

(I) Color development density and speed In the bileaf type pressure-sensitive copying paper color developer sheet, a commercially available top paper (NW-40T manufactured by Jujo Paper Co., Ltd.) containing crystal violet lactone (CVL) as the main pressure-sensitive dye and a color developer sheet were used. With the inner coated surfaces facing each other, place high-quality paper on the top and bottom, and use high-quality paper on the top and bottom of the single-leaf type pressure-sensitive copying paper developer sheet, and develop a cobalt blue color using an electric typewriter.
Determine the reflectance using an SS type Hunter colorimeter using an amber filter. The color density was measured 1 minute after the striking pressure was generated and 20 hours after color development, and the reflectance was 1. , I, , I2 is used. It is preferable that the difference between the initial color development rate and the final color development rate is small and the final color development rate is high, both in terms of color development rate and density.

(n) Whiteness of color developer sheet Four color developer sheets coated and dried using the method described above are stacked one on top of the other, and the reflectance is determined using a Hunter colorimeter with a blue filter. The whiteness (whiteness) of the color developer sheet is expressed as reflectance (F), and the larger (F) is, the whiter the color developer sheet is, and the difference can be determined with the naked eye at about 0.5 points. .

(m) A color developing sheet that has not undergone light yellowing is irradiated with sunlight for 10 hours, and the reflectance before and after irradiation is 1. 2 (using Hunter colorimeter, blue filter). The difference between 1 and 2 indicates the degree of yellowing of the color developer sheet due to photooxidation yellowing of the polyvalent metal compound of the salicylic acid resin and photoyellowing of the dispersant.

The degree of photoyellowing is expressed as Δ=K, -K2, and the smaller ΔK is, the less the photoyellowing of the color developer sheet is.

(It/) Yellowing due to NOx Based on JIS L-1055 [Test method for nitrogen oxide gas fastness of dyed products and dyes], the color developer sheet was
The sample was stored for 1 hour in a closed container in an atmosphere of NOx gas generated by the reaction between (sodium nitrite) and 83PO4 (phosphoric acid), and the degree of yellowing was examined.

The reflectance is measured using a Hunter colorimeter (using a blue filter) before and 1 hour after the NOx gas treatment.

Difference ΔL between reflectance L1 before treatment and reflectance L2 after treatment =
The smaller L and -L2, the less NOx yellowing of the color developer sheet.

Next, a synthesis example of the salicylic acid resin metal compound used in Examples and Comparative Examples will be shown.

Synthesis Example 1 Methyl salicylate 15.2g (0.1 mol), 1.
2-dichloroethane 50I 11.96% concentrated sulfuric acid 3.75
g was placed in a glass reactor, and 52 g (0.5 mol) of styrene was added dropwise thereto over 6 hours at 0 to 2° C. while stirring vigorously.

Thereafter, the reaction was completed by aging at the same temperature for 3 hours. Next, 50 g of an 85% aqueous sulfuric acid solution was added to the reaction solution and heated to distill off 1,2-dichloroethane. To this was added 1 layer of acetic acid 50, and a hydrolysis reaction was carried out under reflux for 18 hours. After the reaction was completed, the reaction solution was poured into water at 300 mA, and when left standing, a brown resin precipitated. This was tilted to discard the upper layer of water, and was further washed twice with 300 ml of warm water.

The weight average molecular weight of the obtained salicylic acid cocondensation resin was 96.
It was 0. This resin was placed in another reactor and the temperature was 150.
A premix of 16.3 g of zinc benzoate and 10 g of ammonium bicarbonate at ~160° C. was gradually added over 30 minutes. After the addition, stirring was continued at the same temperature for 1 hour, the mixture was discharged, cooled, and pulverized to obtain 79.5 g of zinc benzoate modified salicylic acid resin.

The softening point of this product was measured using a ring and ball softening point measuring device according to JIS-To 2548 and found to be 82°C. This is referred to as salicylic acid resin polyvalent metal compound [A].

Synthesis Example 2 22.8 g (0.1 mol) of benzyl salicylate, 75 ml of methylene chloride, and 15.9 g of 1.96% concentrated sulfuric acid were charged into a glass reactor, and 83.2 g (0.8 mol) of styrene was added at a temperature of 5 to 12°C. The mixture was added dropwise over 8.5 hours to react.

After aging at the same temperature for 3 hours, the mixture was neutralized with diluted ammonia water and separated to obtain a methylene chloride solution of the co-condensed resin. The weight average molecular weight of this co-condensed resin was 1,380. Next, the solvent is distilled off while heating the solution, and 120
Do not raise the temperature to ℃. 35 g (0.05 mol) of a 20% aqueous zinc chloride solution was added dropwise to the slightly viscous cocondensation resin, and the mixture was stirred under reflux for 12 hours. After that, the temperature was increased to 140℃.
After stirring for 2 hours, 250m of toluene was added.

Next, keep the temperature at 70-80℃.

7.3 g (0.12 mol) of 28% aqueous ammonia was added dropwise to the mixture and stirred for 1 hour. Next, the mixture was allowed to stand still and the lower aqueous layer was separated and removed, and then the temperature was raised to distill off toluene. The reddish-brown resin liquid was discharged, cooled, and then pulverized to obtain 93.5 g of a zinc-modified salicylic acid cocondensation resin. The softening point of this material was 76°C. This is referred to as salicylic acid resin polyvalent metal compound [B].

Synthesis Example 3 In the first stage reaction of Synthesis Example 1, 38.4 g (0.3 mol) of p-methylstyrene was used instead of styrene, and a similar reaction was carried out. Next, 80 g (0.2 mol) of a 10% caustic soda aqueous solution was added to this reaction solution, and the temperature was increased to distill off the solvent. Then, a hydrolysis reaction was carried out at a temperature of 100 to 102°C for 12 hours. The reaction solution was a slightly cloudy solution, and after diluting it with 850 ml of water, 400 g (0.07 mol) of a 5% aqueous zinc sulfate solution was added dropwise at a temperature of 20 to 25° C. over 3 hours. The precipitate was filtered, washed with water, and dried under vacuum to obtain 52 g of white salicylic acid resin zinc salt. The softening point was 1112°C. This is referred to as salicylic acid resin polyvalent metal compound [C].

Synthesis Example 4 A salicylic acid cocondensation resin having a weight average molecular weight of 720 was obtained in the same manner as in Example 1 except that α-methylstyrene was used instead of styrene in the reaction of Synthesis Example 1. Add 4.1 g (0.05 mol) of zinc oxide to this resin and
When the reaction was carried out at a temperature of 0° C. for 2 hours, 76 g of a zinc-modified salicylic acid cocondensation resin was obtained which was transparent and reddish brown. The softening point was 71°C. This is converted into salicylic acid resin polyvalent metal compound [
0].

Example-1 2-acrylamido-2-methylpropanesulfonic acid N
25 g of a 20% aqueous solution of polyvinyl alcohol (average degree of polymerization 300, degree of saponification 90%) containing 5 mol% a unit and 1 mol% of water.
100 g of the fine powder of the salicylic acid resin polyvalent metal compound (A) obtained in Synthesis Example 1 was charged into an aqueous solution in which 35.7 g of the polyvalent metal compound (A) was mixed in advance and the pH was adjusted to 8.0. A white aqueous suspension (solid content: 40% by weight) having an average particle size of 2.5 μm was obtained by processing for 3 hours with a sand glider using 1 mm glass beads as a measure.

Example 2 An ethylene sulfonic acid-vinyl acetate copolymer containing 313 mol% of ethylene sulfonic acid was saponified with caustic soda to produce polyvinyl alcohol (containing 3 mol% of sulfonic acid groups and 1 mol% of acetyl groups). Average degree of polymerization 3
00) was obtained.

20% of the polyvinyl alcohol having sulfonic acid groups
In a pre-mixed aqueous solution of 50 g of aqueous solution and 90 g of water (
After charging 100 g of the polyvalent metallized salicylic acid resin (B) obtained in Synthesis Example 2 to a solution (pH 8.4) and stirring to form a slurry, an attritor (manufactured by Mitsui Miike Seisakusho, diameter 5III m) was prepared.
A white aqueous suspension (solid content: 45!1I%, average particle size: 2.4 μm) was obtained by dispersion treatment for 5 hours using a zirconium measure (using a zirconium measure) under water cooling.

Example-3 Sulfonated polyvinyl alcohol obtained by adding polyvinyl alcohol to 80% sulfuric acid (kept at 0°C) and reacting it, then neutralizing and purifying it (5 mol% of Kaneko Zimmer unit) An aqueous solution prepared by preliminarily mixing 25 g of a 20% aqueous solution of the corresponding sulfone group and 10 mol% acetyl group and 85 g of water was heated to 90°C, and the salicylic acid resin polyvalent metallized product obtained in Synthesis Example 3 (C ) Add 100g,
After high-speed emulsification and dispersion using a homomixer (manufactured by Tokushu Kikako), the mixture was cooled to room temperature to obtain a white aqueous suspension (average particle size: 2.1 μm) with a solid content of 50% by weight.

Example 4 15 g of a 20% aqueous solution of polyvinyl alcohol (average degree of polymerization 250, degree of saponification 88%) containing 5 mol% ethylene sulfonic acid, 6.7 g of a 30% aqueous solution of sodium salt of polystyrene sulfonic acid, and 140.8 g of water. Too much fine powder of the polyvalent metal compound (D) of the salicylic acid condensation resin obtained in Synthesis Example 4 was charged into the aqueous solution mixed with the above, and after stirring to form a slurry, it was heated in a sand mill using glass beads of diameter 1aII11 for 2 hours. The treatment yields a white aqueous suspension (solids content 4
0%, average particle size 2.3 μm).

Example-S Polystyrene sulfonic acid sodium salt (molecular weight 1000
0, degree of sulfonation 70%) and 135.7 g of water were mixed in advance and the p)l was adjusted to 8.0. Charge 100 g of fine powder of A) and prepare a white aqueous suspension (solid content 40 μm) in the same manner as in Example.
wt%, average particle diameter 2.0 μm).

Example 6 In a mixture of 30 g of a 30% aqueous solution of ammonium polystyrene sulfonate (Sanyo Kasei Chemistat 6500) and 88 g of water (adjusted to pH 8.5 with dilute ammonia water, the polyvalent metallized salicylic acid resin obtained in Synthesis Example 2 was added. Example-2 After charging 100 g of fine powder of (B) and stirring to form a slurry
A white aqueous suspension (solid content 45% by weight, average particle size 1.9 μm) was obtained by dispersion treatment in the same manner as above.

Example-7 10 g of a 20% aqueous solution of polyvinyl alcohol containing 5 mol% of ethylene sulfonic acid (average degree of polymerization 250, degree of saponification 88%), 30% aqueous solution of polystyrene sulfonic acid sodium salt (Nippon Gosei 0KS-3376) 100 g of fine powder of the salicylic acid resin polyvalent metal compound (C) obtained in Synthesis Example 3 was charged into an aqueous solution of 5 g mixed with 112.1 g of water, and a closed sand grinder using glass beads with a diameter of 0.8 mm as a measure. (lynomill) for 1.5 hours to obtain a white aqueous suspension (
Solid content: 48%) was obtained.

Example-8 The salicylic acid resin obtained in Synthesis Example-4 was placed in an aqueous solution containing 13.3 g of a 30% aqueous solution of sulfonated styrene-maleic acid copolymer sodium salt (Arco S-5MA-1000) and 117.8 g of water. Polyvalent metal compound CD) 100
After processing for 2 hours in a horizontal sand mill using glass beads with a diameter of 1.0 mm, the average particle size was 2.3μ.
A white aqueous suspension (45% solids) was obtained.

Comparative Example-1 A brown color with an average particle size of 2.8 μm was produced in the same manner as in Example-1 except that the same amount of Na salt of formaldehyde condensation product of naphthalene sulfonic acid was used in place of polyvinyl alcohol having a sulfonic acid group. An aqueous suspension was obtained.

Comparative Example-2 Partially saponified polyvinyl alcohol (Kuraray, Poval 1) was used instead of polyvinyl alcohol having sulfonic acid groups.
An aqueous suspension was prepared in the same manner as in Example-1 except that the same amount of 17) was used. Significant foaming occurred during the stirring slurry process before the sand grinder treatment and during the sand grinder treatment, and even after the treatment, it took a whole day and night for the foam to disappear, resulting in a significantly poor working efficiency. The resulting aqueous suspension was a thick white aqueous suspension with an average particle size of 2.6 μm.

Comparative Example-3 100 g of fine powder of the salicylic acid resin polyvalent metal compound (B) obtained in Synthesis Example-2 was mixed with sodium ligninsulfonate (ITT
Leonia Co., Ozan CD) Log dissolved water 12
0 g, and treated with a sand grinder in the same manner as in Example 1 to obtain a brown aqueous suspension (solid content: 47
．． 8%, average particle size 2.5 μm).

Comparative Example-4 Polycarboxylic acid Na salt (Na salt of copolymer of CS fraction and maleic anhydride...Nippon Zeon Quinflow 54) instead of polyvinyl alcohol having sulfonic acid
When treated with the same amount of 0), the dispersion state was poor and the whole became a hard paste, and could not be taken out as an aqueous suspension.

Comparative Example-5 170 g of p-phenylphenol, 22.5 g of 80% paraformaldehyde, 2.0 g of p-toluenesulfonic acid
g and 200 g of benzene were placed in a glass reactor, heated while stirring, and reacted at 70 to 80° C. for 2 hours while water produced by the reaction was distilled out of the system azeotropically with benzene. After reaction 10% sodium hydroxide aqueous solution 32
0 g was added, and benzene was distilled off by steam distillation. Next, after cooling, dilute sulfuric acid was added dropwise, and the precipitated p-phenylphenol formaldehyde polymer was collected by filtration, washed with water, and dried to obtain 176 g of white powder.

100 g of this p-phenylphenol formaldehyde polymer powder was dissolved in 12 g of a 25% aqueous solution of polycarboxylic acid Na salt (NOF Polystar OM) in 160 g of water.
g, and treated with a sand grinder in the same manner as in Example 1 to obtain a white aqueous suspension (solid content: 39
．． 6%, average particle size 25μ).

Claims (1)

[Claims] (1) Formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (In the formula, R_1 and R_2 represent a hydrogen atom or a methyl group, and R_1 is a hydrogen atom or the number of carbon atoms. represents an alkyl group of 1 to 4), and the structural unit (I) is 5
-40 mol%, structural unit (II) is 60-95 mol%, structural unit (I) is bonded to structural unit (II), and the weight average molecular weight is 500-10,000. (A) an anionic water-soluble polymer consisting of a polyvinyl alcohol derivative or its salt having a sulfonic acid group in the molecule and/or (B) general formula (III) ▲ mathematical formula, chemical formula, table, etc. ▼ (III) (In the formula, R is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and M is an alkali metal or ammonium ion.) An aqueous suspension of a salicylic acid dendritic polyvalent metal compound dispersed in the presence of an anionic water-soluble polymer.