JPS62284780A - Color developer composition for pressure-sensitive recording paper - Google Patents

Abstract

PURPOSE:To obtain a color developer composition for a pressure-sensitive recording paper having excellent color developing property and surface strength, by using a polymer emulsion in which a multivalent metal salt of an aromatic carboxylic acid is incorporated in the disperse phase particles. CONSTITUTION:A multivalent metal salt of an aromatic carboxylic acid to be used is a salt of an aromatic carboxylic acid with a metal such as copper, lead and magnesium. The aromatic carboxylic acid may be benzoic acid, chlorobenzoic acid (o-, m- or p-), nitrobenzoic acid (o-, m- or p-) or the like. The amount of the salt incorporated into the disperse phase articles of an aqueous emulsion of a polymer is not particularly limited, but is preferably 2-100pts.wt. per 100pts.wt. of the polymer in the emulsion. When applying the emulsion to a color developer sheet, it can be applied in the form of a color developer composition prepared by mixing it with an inorganic pigment and, if required, a known color developer. The emulsion is preferably used in an amount of 5-40pts.wt. per 100pts.wt. of the color developer composition.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a color developer composition for pressure-sensitive recording paper, and more specifically, it relates to a color developer composition for pressure-sensitive recording paper. The present invention provides a color developer composition for pressure-sensitive recording paper that uses an aqueous polymer emulsion contained in emulsion particles and has excellent color development and surface strength.

[Conventional technology]

Pressure-sensitive recording paper usually consists of an upper paper coated with microcapsules containing an electron-donating colorless leuco dye and an organic solvent on the back side, and a lower paper coated with an electron-accepting color developer on the surface that reacts with the colorless leuco dye to develop color. The microcapsules are destroyed by placing the coated surfaces of each sheet facing each other and printing under pressure with a Gehrben or typewriter, etc., and the colorless leuco dye in the microcapsules is released together with the organic solvent. It moves to the paper and reacts with the color developer to form a colored recorded image on the coated side of the lower paper. Also, there is a developer seat on the surface, $
In order to create a layer of microcapsules on the same side of the sheet, it is possible to make multiple copies by inserting a sheet of paper between the upper and lower sheets.Another method is to insert the microcapsule layer on the same side of the sheet and the developing color. There is something called a single recording sheet coated with a color developer or a single color-developing paper.The color developer sheet referred to in the present invention refers to any sheet-like material containing a color developer, regardless of its form, as pressure-sensitive copying paper. It is included as a color developing sheet.

Pressure-sensitive recording paper has shown remarkable growth in demand in recent years, and demands for its quality have also become more sophisticated. In particular, the color developing sheet, which serves as the coloring surface, is required not only to provide clear records but also to have improved surface strength that can withstand high-speed printing.

Electron-accepting color developers used in m-color sheets include acid clay minerals such as acid clay, activated clay, attapulgide, and bentonite, acidic polymers such as p-phenylphenol resin, and aromatics such as salicylic acid derivatives. These color developers include metal salts such as zinc salts of group carboxylic acids and aromatic cardanic acids, and these color developers are usually used alone or in combination. The color developer sheet is made by adding inorganic pigments such as kaolin, calcium carbonate, talc, etc. to a coating solution containing the color developer described above, and then adding a binder to adhesively fix these color developers and pigments to the base sheet. Water-soluble polymers such as starch, dextrin, casein, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, polyacrylamide, styrene-butadiene copolymer, methyl methacrylate Butadiene copolymer, acrylonitrile-
Butadiene copolymer.

There are polymer latexes such as vinyl acetate copolymers, acrylic ester copolymers, and carboxy-modified copolymers of these copolymers, and one or more selected from these are added, and It is obtained by blending a dispersant, a pH adjuster, etc. as necessary to form a color developer paint, applying this color developer paint to a base sheet, and drying it.

Naturally, the color development properties of the color developer sheet depend on the color development properties of the color developer, and various new color developers have been proposed, but from the viewpoints of color development, color development stability, paint formulation stability, etc. Recently, phenol resins and zinc salts of salicylic acid derivatives have been particularly frequently used.Commonly used color developers are solid at room temperature, and these color developers are also used in the form of a dispersion in water.

The color development properties of the color developer sheet are better as the amount of developer in the developer coating composition increases, but increasing the amount of developer not only becomes disadvantageous in terms of cost, but also reduces the surface strength of the coated surface. However, problems such as piling are likely to occur during high-speed printing. In addition, by reducing the particle size of the surface coloring agent dispersion, the number of color developer particles is increased, the surface area of the color developer is increased, and the color development property of the color developer sheet is improved by increasing the surface area of the color developer and making it easier to contact with the leuco dye. can be increased. However, it is difficult to obtain a color developer dispersion with a small particle size, and there is also the problem that the obtained small particle size developer easily coalesces. Furthermore, by reducing the particle size of the color developer, the amount of binder required increases, and with the same binder, there is also the problem that the surface strength of the coated surface decreases.

Japanese Patent Publication No. 57-20156 proposes to improve the color development by incorporating phenols into the aqueous emulnot particles and adding a polyvalent metal complex, but the present inventors According to et. It was found that the stability of aqueous emulsions was significantly impaired.

Furthermore, Japanese Patent Application Laid-Open No. 57-152996 discloses a method of incorporating a color developer into microcapsules.
No. 322 and Japanese Unexamined Patent Publication No. 59-155092 propose a method in which a color developer is dissolved in an organic solvent. Although these methods improve color development, they significantly reduce printing durability, and some of the organic solvent evaporates during the coating and drying process, resulting in a safety problem.

On the other hand, attempts have been made to improve color development and surface strength by improving binder latex. Publication No. 57-133093 proposes using a copolymer with an average particle size of 0.08μ or less, but none of these methods can completely satisfy the requirements for color development and surface strength. , further improvement is desired.

[Problem that the invention seeks to solve]

Therefore, an object of the present invention is to provide a color developer composition for pressure-sensitive recording paper having excellent color development and surface strength.

[Means for solving problems]

Thus, according to the present invention, there is provided a color developer composition for pressure-sensitive recording paper, which uses a polymer emulsion in which emulsion particles contain a polyvalent metal salt of aromatic cargenic acid.

The aqueous polymer emulsion used in the present invention contains a polyvalent metal salt of aromatic cargenic acid in polymer emulsolan particles.

Methods for incorporating the polyvalent metal salt into the polymer emulsion particles include adding the polyvalent metal salt to the polymerization system during production of the polymer aqueous emulsion, and adding the polyvalent metal salt into the polymer aqueous emulsion particles after polymerization. In the present invention, any method can be used as long as the polyvalent metal salt is substantially contained in the particles of the aqueous polymer emulsion.

Methods for incorporating the polyvalent metal salt into the particles during polymerization include dissolving the polyvalent metal salt in monomers constituting the polymer, and dissolving the polyvalent metal salt in advance in a non-polymerizable organic solvent. and a method of mixing this solution with monomers,
There is a method in which a solution of the polyvalent metal salt is added to a monomer emulsion. Further, when the polyvalent metal salt has radical polymerizability, the polyvalent metal salt can be bonded to the polymer in the emulsion particles by copolymerizing with another monomer. When the polyvalent metal salt is used after being dissolved in a non-polymerizable organic solvent, it is preferable to distill off and recover the non-polymerizable organic solvent by vacuum distillation or the like after the completion of polymerization.

As a method for incorporating the polyvalent metal salt into the aqueous polymer emulsion particles after completion of polymerization, an organic solvent capable of swelling the polymer in the aqueous polymer emulsolan particles is used, and the polyvalent metal salt is added to the organic solvent in advance. The metal salt is dissolved in a bath, this solution is added to the aqueous polymer emulsion, stirred, and the solution is absorbed by the polymer in the aqueous polymer emulsolan particles, and then the organic solvent is distilled off and recovered by vacuum distillation or the like. , a method in which the polyvalent metal salt remains in the Emulsoyo 7 particles, and the like.

The polyvalent metal salts of aromatic carboxylic acids used in the present invention are metal salts of aromatic carboxylic acids such as copper, lead, magnesium, calcium, zinc, aluminum, tin, and nickel.

Specific examples of aromatic carboxylic acids include benzoic acid, chlorobenzoic acid (Oem #P), and nitrobenzoic acid (
0+ In v p ), toluic acid (0+ m e
p), 4-methyl-3-nitrobenzoic acid, fragrant acid, 2-chloro-4-nitrobenzoic acid, 2,3-dichlorobenzoic acid, 2,4-dichlorobenzoic acid, p-inglobil benzoic acid , 2,5-dinitrobenzoic acid, p-tart-butylbenzoic acid, N-2 enyl anthranilic acid, 4-methyl-3-nitrobenzoic acid, salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 3 .5-dinitrosalicylic acid, 5-tart-butylsalicylic acid, 3-phenylsalicylic acid, 3-methyl-5-t@rt-butylsalicylic acid, 3,5-di-tart-butylsalicylic acid, 3,5-nort-amyl Salicylic acid, 3-cyclohexylsalicylic acid, 5-cyclohexylsalicylic acid, 3-methyl-5-yamylsalicylic acid, 5-yamylsalicylic acid, 3,5-no-5ec-butylsalicylic acid, 5-nonylsalicylic acid, 2-hydroxy-3 -Methylbenzoic acid, 2-hydroxy-5-tert-butylbenzoic acid, 2,4-cresotic acid, 5.5-methylenethusalicylic acid, acetaminobenzoic acid (o@m*p), 2
．． 4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, anacardic acid, l-naphthoic acid, 3.5-no α, α-tumethylbennorsalicylic acid, 3.5-no α
-Methylbenzylsalicylic acid, 2-naphthoic acid, l-hydroxy-2-naphthoic acid, 2-hydroxy-3-naphthoic acid, 2-hydroxy-1-naphthoic acid, thiosalicylic acid, 2-cartoxybenzaldehyde, etc. Can be done.

In the present invention, it is essential to use polyvalent metal salts of these aromatic carboxylic acids, and zinc salts are particularly preferred. When an aromatic carboxylic acid is used, the effect of improving color development is inferior to that of the present invention, and cannot be said to be sufficient. In addition, an aqueous polymer emulsion obtained by incorporating an aromatic carboxylic acid into an emulsion polymerization system, a metal oxide such as zinc oxide, a metal salt such as zinc chloride, or a metal complex compound such as a zinc complex compound of glycine can be used. If the color developer is present in the composition, the color development performance will be insufficient, and the stability of the coating composition will be significantly impaired, resulting in the generation of coagulum and an increase in the viscosity of the composition. This is not desirable because it reduces aptitude.

The amount of the polyvalent metal salt of aromatic cargenic acid added to the aqueous polymer emulsion particles is not particularly limited, but is 2 to 1 part by weight per 100 parts by weight of the polymer in the aqueous polymer emulsion.
A range of 00 heavy-duty areas is preferable. If it is less than 2 parts by weight, the intended effect of improving color development will be small, and if it exceeds 100 parts by weight, the ability of the polymer aqueous emulfuran as a binder will decrease, which is not preferable. Preferably it is in the range of 5 to 50 parts by weight.

The monomer composition constituting the aqueous emulso-4/polymer used in the present invention is not particularly limited as long as it has adhesive strength.

Examples of monomers constituting the polymer include the following.

Aliphatic conjugated diolefins such as 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-methyl-1,3-butanoene, halodane-substituted butanoene; styrene, α-methylstyrene, monochlorostyrene, vinyl Aromatic vinyl compounds such as toluene; methyl acrylate,
Methyl methacrylate.

Ethyl acrylate, butyl acrylate, acrylic acid-2
Examples include alkyl esters of acrylic acid and methacrylic acid such as -ethyl-hexyl; and ethylenically unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile. More acrylic! 2. methacrylic acid,
A carboxylated carboxylic acid can also be obtained by using a non-anastogenic calgenic acid such as itaconic acid or maleic acid as a copolymerization monomer. Furthermore, acrylic acid-β-hydroxyethyl, acrylamide, methacrylamide, N-methylolacrylamide, glycidyl methacrylate, divinylbenzene, etc. 't A'? ! It can also be used as a coalescing monomer.

Examples of copolymerization of a monomer composition having adhesive strength by combining these monomers include SR latex, MB latex, NB latex, acrylic ester latex, and their carboxymolar ratio modification. Examples include latex.

In the present invention, it is necessary to contain the polyvalent metal salt of aromatic cargenic acid in the aqueous polymer emulsion particles, and the polymerization method itself of the aqueous polymer emulsion particles is not particularly limited, such as batch emulsion. Known emulsion polymerization methods such as polymerization, continuous emulsion polymerization, etc. can be employed, and various known emulsifiers may be used.

Various additives used in general emulsion polymerization, such as polymerization initiators, chelating agents, and electrolytes, can be used, and the polymerization temperature can be selected from either high or low temperatures. Further, a known pH adjuster, dispersant, preservative, etc. may be added to the aqueous polymer emulsion after completion of polymerization.

A method for incorporating the polyvalent metal salt during polymerization includes dissolving it in monomers.

Ahe value) The compound is converted into a quinomer phase, which is then emulsified and sent to a polymerization system. At this time, it is possible to refine the mixture of each monomer of the copolymer composition, but it is also possible to dissolve it in a specific monomer. Depending on the FJm of the monomer, the solubility of the polyvalent metal salt may not reach the desired addition 1. In this case, the polyvalent metal salt may be dissolved in a non-polymerizable solvent in advance and then added to the total polymerization system. In this case, it is necessary to recover the solvent by distillation under reduced pressure after the emulsion polymerization is completed. The solvent used must have a high solubility of the cough polyvalent metal salt, a low boiling point, and be easy to recover. Examples of solvents used are ethyl acetate, methyl ethyl ketone, and tetrahydrofuran.

Examples include.

Nuclear polymetal salts can also be included after polymerization of the aqueous polymer emulsion. The polyvalent salt is dissolved in an organic solvent, and the solvent is added to the aqueous emulfuran containing the entire polymer and stirred. The solvent containing the polyvalent metal salt swells the polymer particles of the aqueous polymer emulsion, so that the particles contain the organic solvent and the polyvalent metal salt. Then, by vacuum distillation etc.
Only the organic solvent is distilled off and recovered to obtain an aqueous polymer emulsion containing the polyvalent metal salt in its particles. The solvent used must have a high solubility of the polyvalent metal salt, a high degree of swelling in the aqueous polymer emulsion, and a low boiling point so that it can be easily recovered, but there are no particular restrictions on the type. Examples of solvents used include esters such as ethyl acetate, ketones such as methyl ethyl ketone, furan derivatives such as tetrahydrofuran, and halogenated hydrocarbons such as carbon tetrachloride and vinyl chloride.

When applying the polymer aqueous emulsion 17't-color developer sheet of the present invention, it may be mixed with an inorganic pigment and, if necessary, a known color developer, and applied as a color developer composition. In this case, it is desirable that the aqueous polymer emulsion of the present invention be added in an amount of 5 to 40 parts by weight (solid content) per 100 parts by weight (solid content) of the primary colorant composition.

Furthermore, the water-soluble polymer binder mentioned above can be added to the color developer composition, and known polymer latexes may also be used in combination as binders as long as they do not impede the effects of the present invention.

In applying the color developer composition thus obtained onto the base paper, known methods can be applied, such as an air knife coater, a roll coater, a grade coater, etc. The coloring agent composition can be set to have a coating concentration and coating viscosity suitable for the coating equipment to which it is applied. Furthermore, known dispersants, antifoaming agents, surfactants, and viscosity modifiers are used to improve the coating suitability of paints.

It is also possible to add preservatives etc.

〔Effect of the invention〕

Thus, according to the present invention, aromatic cargenic acid polyvalent metal salt can be emulsified! By using an aqueous polymer emulsion contained in the particles, fc has excellent color development and surface strength.
A fastener composition for g-pressure recording paper is provided.

The present invention will be described in more detail below with reference to Examples. Note that parts and percentages in Examples and Comparative Examples are based on heavy electrical equipment unless otherwise specified.

Example 1 Water and emulsifier in a pressure-resistant glass gedol with an internal volume of about 11.

Together with an inorganic salt, a chelating agent, and a polymerization initiator, a monomer 2 molecule i regulator shown in Table WJ1, an aromatic carboxylic acid polyvalent gold beak salt, and a non-polymerizable organic solvent were added, and the mixture was heated at 60°C for 15 hours with rotational mixing. The reaction was carried out. The conversion rate is 9 in both cases.
Reached over 9 inches. The obtained polymer latex was cooled with water, unreacted ridges and solvent were removed, and then the − of the latex was adjusted to 7 with NaOH.

The paint was adjusted using the formulation shown in Table 2 so that the paint solids concentration was 25%. 40 gr/m'' or base paper was coated with the paint to a coating amount of 4 to 5 gr/m'' (solid content), and then dried to obtain an enveloping sheet.

The performance of the obtained color developing sheet was evaluated by the following method.

■ Color development level Commercially available paper coated with microcapsules containing colorless leuco dye is layered on a color development sheet, and then printed using an electric typewriter.
was used to print, the reflectance was measured after 1 hour, and the degree of color development (Q) was determined using the following formula.

■ Using a surface strength RI printing aptitude tester (Mei Seisakusho), printing was performed four times on the coated surface of the ink t-developing sheet for picking test of Tacpal J$-12, and the state of powder falling off was sensory evaluated. . Evaluation was made on a 5-point scale based on the following criteria.

Evaluation Points Standards 5 No powder falling off 4. There is a slight amount of powder falling off. 3 There is a drop of '8 in some parts. 2. There is discoloration on the entire surface. 1. There is significant powder falling on the entire surface. Table 2 The above results are shown in Table 5.

Comparative Example 1 A copolymer latex was obtained in the same manner as in Example except that a regulator was used for two monomer molecules shown in Table 3.

In (V) to (■) in Table 3, emulsion copolymerization was carried out by adding phenols to the polymerization system. In the system (V) in which salicylic acid was added, stability during polymerization was poor and an aqueous emulsion could not be obtained.

Using the obtained latex, paints were prepared according to the formulations shown in Table 4.

In the formulations (8) and (9) of Table 4, a zinc complex compound of dalicin was added, but caution was required when adding it because if it was added directly to the aqueous emulsion well, coagulite would form.

A color developing sheet was prepared in the same manner as in Example 1, and the color developing sheet was evaluated.

The results are shown in Table 5.

Example 2 4 parts of zinc 3,5-t-butylsalicylate are dissolved in 10 parts of tetrahydrofuran. Comparative Example 1
It is added to 20 parts (solid content) of the latex (1) obtained in step 1, and stirred for 3 hours using a stirrer.

Tetrahydrofuran was distilled off under reduced pressure to obtain latex V). Create a paint according to the formulation (h) in Table 2,
A color developing sheet was prepared in the same manner as in Example 1 and evaluated. The results are shown in Table 5.

Comparative Example 2 4 parts of zinc 3.5-butylsalicylate to 1
The mixture was added to 10 parts of -isopropylphenyl-2-phenylethane and dissolved by heating. This was added to 20 parts of a 1% aqueous solution of sodium alkylbenzenesulfonate (1X) with stirring, and further emulsified using homonaive to obtain an organic developer-containing organic solvent emulsion (a).

A paint was prepared according to the formulation α→ shown in Table 4, and a color developer 7-t was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 5.

Table 5

Claims (1)

[Claims] A color developer composition for pressure-sensitive recording paper, characterized in that it uses an aqueous polymer emulsion containing a polyvalent metal salt of an aromatic carboxylic acid in emulsion particles.