JPH04118281A - Single layer type color self-forming pressure-sensitive recording sheet - Google Patents

Abstract

PURPOSE:To enhance sensitized ink permeability by adding a specific org. compound to a coating layer. CONSTITUTION:A compound represented by formula I (wherein R1 and R2 are a 4-12C alkyl group) is added to a color forming layer based on a microcapsule including a color former dissolved in a high b.p. solvent and an org. developer. As this compound, sodium dibutyl succinate is concretely used but, pref., there are sodium diheptyl succinate, sodium dioctyl succinate and sodium dinonyl succinate. The addition amount of the compound represented by the formula I is 0.05-3 pts.wt., pref., 0.1-1 pts.wt. per 100 pts.wt. of the org. developer. In the case of below 0.05 pts.wt., permeability enhancing effect is low and, in the case of above 3 pts.wt., developed color density is lowered. As the org. developer, there are a novolac type phenol resin, a polyvalent metal salt of aromatic carboxylic acid and a polyvalent metal salt of a salicylic acid resin.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a single-layer type self-coloring pressure-sensitive recording sheet, and more particularly to improving the permeability during printing with desensitized ink.

[Conventional technology]

Self-coloring pressure-sensitive recording sheets are developed from so-called carbonless pressure-sensitive recording sheets and are also called self-contained papers. A method in which a layer coated with microcapsules (hereinafter referred to as a color developer) dissolved in a high-boiling solvent and an electron-accepting acidic substance (hereinafter referred to as a color developer) is coated and laminated; There is a method of applying a single layer. Self-coloring pressure-sensitive recording sheets can produce pressure-sensitive coloring images even with a single sheet of paper, and have unique features such as being able to print directly without using a type ribbon, and by placing high-quality paper on top and writing with a ballpoint pen, a copy record can be obtained. Due to its effectiveness, the demand for it has continued to increase in recent years. As a coloring agent, crystal violet lactone, 3
-3-bis(P-dimethylaminophenyl)natutalide, 3-(P-dimethylaminophenyl')-3-(2
-methylindol-3-yl) 6-dimethylaminophthalide and other acyl derivatives of benzoyl, anizoyl, and pivaloyl of methylene blue: 3-diethylamino-6-methyl-7-
Chlorofluorane, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-6methyl-7-anilinofluorane, 3-methylcyclohexylamino-6-methyl-7-anilinofluorane, 3-ethyl- Examples include xanthine phthalides such as P-tolylamino 6-methyl-7-anilinofluorane. These color formers are high boiling point solvents such as alkylnaphthalenes typified by diisopropylnaphthalene, diallylakanes typified by 1-phenyl-1-xylylethane, alkylbiphenyls typified by isopropylbiphenyl, and other triallyldimethanes. Aromatic hydrocarbons such as alkylbenzenes, benzylnaphthalenes, diallylalkylenes, and allylindanes; Carboxylic acid ester compounds represented by dibutyl phthalate, dioctyl maleate, diethyl azelaate, etc.; tricresyl phosphate Phosphate ester compounds represented by; used dissolved in vegetable oils such as castor oil, soybean oil, cottonseed oil, or their modified oils, natural high-boiling fractions (consisting of aliphatic hydrocarbons) such as mineral oils, etc. . Conventional microencapsulation methods include coacervation methods, in-situ polymerization methods, and interfacial polymerization methods. As a color developer, an inorganic color developer such as acid clay, natural clay minerals such as attapulgide, activated clay obtained by lightly or moderately treating acid clay, which is a montmorillonite clay mineral, with a mineral acid, and JP-A-5'7 - There are semi-synthetic solid acids described in Publication No. 15996, and organic color developers such as various phenolic compounds, novolak type phenolic resins, polyvalent metal salts of aromatic carboxylic acids, and recently proposed polyvalent metal compounds of salicylic acid resins. There is. As a method for producing a self-coloring pressure-sensitive recording sheet, first, as described above, a coloring agent is dissolved in a high-boiling point solvent, microencapsulated, and coated with a binder on a support such as paper using an air knife coater or the like, usually in a range of 3 to Log. /rrf (dry weight solids content) and then coated and dried, and then on top of that, finely ground organic color developer is added together with a binder using an air knife coater etc. A self-coloring pressure-sensitive recording sheet is produced by laminated coating and drying to give a so-called laminated type coloring layer (laminated self-coloring pressure-sensitive recording sheet). be able to. Furthermore, microcapsules containing a coloring agent as described above and an organic coloring agent crushed into fine particles are mixed with a binder, and the result is usually 4 to 15 g/rrf (dry weight solid content) using a single air knife coater. There is a method of forming a self-coloring pressure-sensitive recording sheet (single-layer type self-coloring pressure-sensitive recording sheet) having a single-layer type coloring layer by coating and drying.

[Problem to be solved by the invention]

These self-coloring pressure-sensitive recording sheets are used by writing or pressure-printing with a dot printer as a superimposed document with a high-quality paper-self-coloring pressure-sensitive recording sheet. When used as a form by overlapping with high-quality paper, desensitizing ink is applied to areas where coloring is unnecessary to prevent coloring (hereinafter, the degree to which coloring can be prevented is referred to as desensitizing effect). The main component of desensitizing ink is a desensitizer compound, most of which are almost liquid organic compounds with a molecular weight of several hundred or more and having a polyether chain in the molecule, such as polyethylene oxide or polypropylene oxide. It is blended with vehicles, binders, pigments, etc. Normally, desensitized ink printing is done using flexo, gravure, offset, or letterpress methods, and ink drying is achieved by penetrating the printing surface or paper, but the ink penetration is not instantaneous after printing, but occurs several times. A time of 10 minutes or more is required. However, printing operators can determine the amount of ink applied (amount of ink deposited per unit area, g/rrr) that will produce a desensitizing effect by writing it down with a ballpoint pen or the like immediately after printing, or by developing the color using a solvent called a desensitizing checker. The agent is dissolved and sprayed from a built-in cylinder. However, in self-coloring pressure-sensitive recording sheets, the color forming agent and color developer form a laminated or single layer to form the color forming layer, so if the ink does not penetrate into the entire layer, a desensitizing effect can be obtained. It is difficult to judge that the amount of ink is so-called appropriate. This means that if you use an organic developer that has a smaller specific surface area than an inorganic developer and fewer voids, the penetration of ink will be even slower, allowing the ink to penetrate into the entire coloring layer and achieve a desensitizing effect. It takes several hours to determine the amount. Therefore, a countermeasure is to use an excessive amount of ink, but if the amount of ink is increased, the desensitized ink may transfer from the paper roll of the printing machine to the self-coloring pressure-sensitive recording sheet, or the printed self-coloring pressure-sensitive recording sheet may be damaged. There is a problem in which the desensitized ink gradually migrates while being stacked or rolled up and stored, making it impossible to develop color in areas where color development is required. However, organic color developers have excellent properties such as liquid fluidity, color density, and image light fastness, and while they have high commercial value and are attractive from the manufacturing side, they have poor permeability and reduce the work efficiency of printing operators. Considering this, it can be said that it lacks practicality. By the way, as mentioned above, the laminated type needs to be coated twice, which requires a large amount of heat energy and electricity, and in terms of quality, it is difficult to develop color because it has two layers of microcapsules containing a color former and a color developer. The speed is slow and the concentration is low. On the other hand, the single-layer type has the great advantage of improving operability because it only needs to be coated once, and in terms of quality, the microcapsules and color developer are close to each other and coexist, so excellent color development speed and density can be achieved with low pressure. can get. Therefore, an object of the present invention is to provide a single-layer type self-coloring pressure-sensitive recording sheet that uses an organic color developer and has excellent desensitizing ink penetration.

[Means to solve the problem]

As a result of extensive experiments and research, the inventors of the present invention have developed a single-layer type ink that allows desensitizing ink to penetrate quickly even when organic color developers are used, and maintains excellent characteristics such as color development speed and density. A self-coloring pressure-sensitive recording sheet was developed. That is, the present inventors achieved the above object by including a compound represented by the following general formula (I) in a microcapsule containing a color former dissolved in a high boiling point solvent and a color forming layer mainly composed of an organic color developer. The present invention was achieved based on the knowledge that CH2-C0OR+ (I) Nap35-CH-COOR2 (In the formula, R7 and R2 represent integers having 4 to 12 carbon atoms.) The compound (I) formula of the present invention is, for example, specifically sodium dibutylsulfosuccinate, sia One member selected from sodium myrsulfosuccinate, sodium dihexylsulfosuccinate, sodium diheptylsulfosuccinate, sodium dioctylsulfosuccinate, sodium dinolylsulfosuccinate, sodium didecylsulfosuccinate, sodium diundecylsulfosuccinate, sodium dilaurylsulfosuccinate, and/or Although two types are used, particularly preferred are sodium diheptylsulfosuccinate, sodium dioctylsulfosuccinate, and sodium dinonylsulfosuccinate. The amount of compound (I) used in the present invention is 0.05 to 3 parts by weight, particularly preferably 0.1 to 1 part by weight, per 100 parts by weight of the organic color developer. If it is less than 0.05 parts by weight, the effect of improving permeability will be small, and if it exceeds 3 parts by weight, the color density will decrease. The organic color developer used in the present invention is a novolak type phenol resin, a polyvalent metal salt of an aromatic carboxylic acid, or a polyvalent metal compound of a salicylic acid resin. The basic patent for the novolac type phenol resin, which is a polycondensation of a phenol derivative and a lower aldehyde represented by formaldehyde, is Japanese Patent Publication No. 42-20144.
For example, specifically P-octylphenol resin, P-benzylphenol resin, P-cumylphenol resin, P-
-tert-butylphenol resin and P-phenylphenol resin. Polyvalent metal salts of aromatic carboxylic acids are disclosed in Japanese Patent Publication No. 49-10856.
No. 51-25174, No. 52-1327, No. 5
2-7372, etc., but specifically, for example, 4-hydroxybenzoic acid α-phenylbenzyl ester, 4-hydroxybenzoic acid phenethyl, 4-hydroxybenzoic acid-cinnamyl ester, 4-hydroxybenzoic acid Acid-m-fluorobenzyl ester, 4,4'-hydroxy-2,2'-dibutylphenyl sulfone, cinnamyl orcelinate, 5,5-monethylenebis-2,
4-dihydroxybenzylic acid benzyl ester, m-phenylphenoxyethyl orselinate, bisphenol A bisP-hydroxybenzoic acid ester, 2.4-
dihydroxybenzoic acid-P-methylbenzyl ether,
2.4-dihydroxy6-methylbenzoic acid-0-methylbenzyl ester, 4.4-diacetyldiphenylurea, 5-P-α-methylbenzyl-α-methylbenzylsalicylic acid, 5-P-benzyl-α-methylbenzyl Salicylic acid, 3-xylyl-5(α,α-dimethylbenzyl)salicylic acid, 3-5-di(α-methylbenzyl)salicylic acid, 2-hydroxy-1-α-ethylbenzyl-
Examples include 3-naphthoic acid. Calcium, magnesium, copper, zinc, tin, barium, cobalt, etc. are used as polyvalent metal salts, and zinc is particularly effective. Polyvalent metallization of salicylic acid resin is disclosed in JP-A-63-186.
No. 729 and No. 63-254124 in detail, for example, zinc salt of 3-5-di(4-methylbenzyl)salicylic acid resin produced by reacting styrene, 0-methyl Zinc salt of 5-(4-methylbenzyl)salicylic acid resin produced by reacting styrene,
Zinc salt of 3-phenylsalicylic acid resin produced by reacting with styrene; Zinc salt of 3-5-di(4-methylbenzyl)salicylic acid resin produced by reacting with benzyl chloride, P-methylbenzyl chloride. Examples include a zinc salt of the produced 5-(α,α-dimethylbenzyl)salicylic acid resin and a zinc salt of 3-tert-butyl-5-phenylsalicylic acid resin produced by reacting 2-4-dimethylbenzyl chloride. Examples of the pigments used in the present invention include inorganic pigments such as kaolin, calcined kaolin, natural silica, titanium oxide, and calcium carbonate; synthetic silica, styrene-methacrylic acid copolymer, urea-formaldehyde condensate, polystyrene resin, etc. One and/or two types are selected from these organic pigments, and a urea-formaldehyde condensate is particularly preferred. The binders such as microcapsules containing a color forming agent, color developer, and pigments used in the present invention include, for example, starch, phosphoric acid ester starch, casein, polyethylene oxide, polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, etc. Water-soluble polymers include latex emulsions that are styrene-butadiene-based, acrylic-based, and vinyl acetate-based hydrophobic polymers. The present invention may optionally include a dispersant, a capsule protectant, an antifoaming agent,
It is made into a single-layer self-coloring pressure-sensitive recording sheet coating liquid together with a preservative, and coated on a support such as paper with an air knife coater of 4 to 15 g/rr. (dry weight solid content) and dry. Particularly preferred coating amount is 5 to 10 g/rT
? It is.

【Example】

Hereinafter, preferred embodiments and excellent effects of the present invention will be specifically explained using the most typical examples. Note that all parts below are by weight, and all % represents weight %. Example 1 [Method for creating microcapsules containing 40% color former] Crystal violet lactone (CVL) 5 as a color former
After heating and dissolving 95 parts of phenyl xylylethane (boiling point 296°C), which is a high boiling point hydrocarbon oil, 120 parts of a 5% aqueous solution of styrene maleic anhydride copolymer (pH 4,8) was added.
and emulsified at a liquid temperature of 60° C. to an average particle size of 4.5 μm. Add 12.5 parts of melamine and 16.1 parts of a 37% formaldehyde aqueous solution to 60 parts of water, dissolve by heating at pH 9.5 to obtain a melamine-formaldehyde initial condensate, and add to the above emulsion at 75°C with stirring. After reacting for 2 hours, the pH of the solution was adjusted to 8.5 at a temperature of 40° C. or below, and 4096 color former-containing microcapsules were prepared. [25 parts Method for preparing a color developer dispersion (A)] P-phenylphenol resin 100 parts 10% sodium polyacrylate aqueous solution 30 parts Water 270
The above mixture was ground in a ball mill so that the average particle size was 3 μm to prepare a 25-part color developer dispersion (A). [Method for preparing 10% urea-formaldehyde condensate dispersion] Urea-formaldehyde condensate 100 parts 10% sodium polyacrylate aqueous solution 50 parts Water 850 parts The above mixture was ground with a ball mill so that the average particle size was 4 μm, A 10% urea-formaldehyde condensate dispersion was prepared. Add 80 parts of wheat starch to 342 parts of water, disperse and mix,
The above 10% urea-formaldehyde condensate dispersion 200
50 parts, 40% color former-containing microcapsules, 25 parts Color developer dispersion (A) 40 parts, 1% aqueous sodium dioctyl sulfosuccinate aqueous solution 05 parts, 10% polyvinyl alcohol aqueous solution 100 parts, 5096 parts carboxy-modified styrene butadiene 20 parts of latex were sequentially dispersed and mixed to prepare a coating solution. This coating liquid was applied to a high-quality paper with a basis weight of 40 g/rrl using an air knife coater in a coating amount of 6 g/rrf (dry weight solid content) to prepare a single-layer self-coloring pressure-sensitive recording sheet. Example 2 A single-layer self-coloring pressure-sensitive product was prepared in the same manner as in Example 1, except that 342 parts of water in Example 1 was reduced to 327 parts, and 65 parts of 1% dioctyl sodium sulfosuccinate aqueous solution O was increased to 15 parts to prepare a coating solution. A record sheet was created. Example 3 A single-layer self-coloring texture was prepared in the same manner as in Example 1, except that the amount of water in Example 1 was reduced from 342 parts to 312 parts, and the 1% aqueous solution of sodium dioctyl sodium sulfosuccinate was increased to 30 parts to prepare a coating solution. A pressure recording sheet was created. Example 4 [Method for preparing a 25-part color developer dispersion (B)] 3-5-di(
α-Methylbenzyl)zinc salicylate
100 parts 10% aqueous sodium polyacrylate solution 30 parts Water 270 parts The above mixture was ground in a ball mill to an average particle size of 3 μm to prepare a 25-part developer dispersion (B). Add 80 parts of wheat starch to 327 parts of water, and after dispersing and mixing,
200 parts of 10% urea-formaldehyde condensate dispersion,
50 parts of microcapsules containing 40% color former, 25 parts Color developer dispersion (B) 40 parts, 1% aqueous solution of sodium dioctyl sulfosuccinate 15.100 parts of 10% aqueous polyvinyl alcohol solution, 50% carboxy-modified styrene butadiene latex 20 These parts were sequentially dispersed and mixed to form a coating solution. Apply this coating liquid to high-quality paper with a basis weight of 40 g/rri in an amount of 6
g/rr? (dry weight solid content) using an air knife coater to prepare a single-layer self-coloring pressure-sensitive recording sheet. Example 5 [Method for preparing a 25-part color developer dispersion (C)] Zinc 3-tert-butyl-5-phenylsalicylate
100 parts 10% aqueous sodium polyacrylate solution 30 parts Water 270 parts The above mixture was ground in a ball mill to an average particle size of 3 μm to prepare a 25-part developer dispersion (C). A single-layer self-coloring pressure-sensitive recording sheet was prepared in the same manner as in Example 4, except that the same amount of the 25 parts developer dispersion (B) in Example 4 was replaced with the 25 parts developer dispersion (C) to prepare a coating solution. Created. Example 6 A single-layer self-coloring pressure-sensitive recording sheet was prepared in the same manner except that 0.5 parts of the 1% dioctyl sodium sodium sulfosuccinate aqueous solution in Example 1 was replaced with the same amount of the 1% dibutyl sodium sodium sulfosuccinate aqueous solution as the coating solution. Created. Example 7 A single-layer self-coloring pressure-sensitive recording sheet was produced in the same manner except that the 1% aqueous solution of sodium dioctyl sulfosuccinate (05%) in Example 1 was replaced with the same amount of an aqueous solution of 196 dilauryl sodium sulfosuccinate to prepare a coating solution. Created. Comparative Example 1 50 parts of activated clay was added to 255 parts of water in which 0.5 parts of sodium pyrophosphate, a dispersant, was dissolved, and after complete dispersion and mixing, 80 parts of wheat starch, 200 parts of a 10% urea-formaldehyde condensate, 50 microcapsules with built-in 40% coloring agent
parts, 100 parts of 10% polyvinyl alcohol aqueous solution, 50 parts
% carboxy-modified styrene-butadiene latex were sequentially dispersed and mixed to prepare a coating solution. Apply this coating liquid with a basis weight of 4
Is the coating amount 10g/'rT on high-quality paper of 0g/rrr? (dry weight solid content) using an air knife coater to prepare a single-layer self-coloring pressure-sensitive recording sheet. Comparative Example 2 A single-layer self-coloring pressure-sensitive recording sheet was prepared in the same manner as in Example 1 except that 05 parts of 1% sodium dioctyl sulfosuccinate was used as the coating solution. Comparative Example 3 A single-layer color-forming pressure-sensitive recording sheet was prepared in the same manner as in Example 4, except that the amount of water in Example 4 was increased from 327 parts to 342 parts, and 1% sodium dioctyl sulfosuccinate (15) was removed from the coating solution. Comparative Example 4 A single-layer color-forming pressure-sensitive recording sheet was prepared in the same manner as in Example 5, except that the amount of water in Example 5 was increased from 327 parts to 342 parts, and 1% sodium dioctyl sulfosuccinate (15) was removed from the coating solution. Comparative Example 5 A single-layer self-coloring pressure-sensitive recording sheet was prepared in the same manner except that 0.5 parts of the 1% sodium dioctylsulfosuccinate aqueous solution in Example 1 was replaced with the same amount of the 1% sodium dipropylsulfosuccinate aqueous solution to prepare a coating solution. It was created. Comparative Example 6 A single-layer pressure-sensitive recording sheet was prepared in the same manner except that 0.5 parts of the 1% sodium dioctyl sulfosuccinate aqueous solution in Example 1 was replaced with the same amount of the 1% sodium ditridecyl sulfosuccinate aqueous solution to prepare the coating liquid. did. (Test method) ◎Evaluation of color development speed and density The prepared single-layer self-coloring pressure-sensitive recording sheet was passed through a super calendar to develop color, and the color density after 1 minute and 1 hour was measured using a color difference meter.The following values were obtained. I asked for it. The time after 1 minute was taken as the color development rate, and the time after 1 hour was taken as the color development density. A small value indicates a high developed color density. Reflectance color density (%) of coloring part = xio. Reflectance of white background ◎ Penetration of desensitizing ink (Evaluate the penetrating property from the desensitizing effect immediately after printing) For Mitsubishi Toppan (
TT-1) Use desensitizing ink “Myaster 18” manufactured by Miyakoshi Seisakusho.
Immediately after printing on a single-layer type self-coloring pressure-sensitive recording sheet with an ink amount of 1.2 g/rrf using a printing machine, it was printed on high-quality paper (
Pressure printing was performed using a dot printer with a basis weight of 50 g/rrf), and the desensitizing effect of the printed portion immediately after printing and further 2 hours after printing was evaluated by visual observation. Tables 11, 2, and 3 show the results of ink permeability evaluated from color development speed, color density, and desensitization effect for Examples 1 to 5 and Comparative Examples 1 to 4. Table 1 (Test results) Table 2 (Evaluation) Table 3 (Evaluation) ○Good to slightly inferior × Bad

【Effect of the invention】

As is clear from the present invention, by including the compound represented by the following general formula (I) in the color forming layer containing the color forming agent-containing microcapsules and organic color developer as main components of the present invention, the permeability of the desensitizing ink is improved. A single-layer self-coloring pressure-sensitive recording sheet was obtained which was fast, had an excellent desensitizing effect immediately after printing, and maintained excellent properties such as coloring speed and coloring density. CH2-C0OR. NaO3S CHC00R2 (In the formula, R1 and R2 represent integers having 4 to 12 carbon atoms.)

Claims (1)

[Scope of Claims] 1. A single-layer self-coloring pressure-sensitive recording sheet comprising a coating layer containing microcapsules containing an electron-donating dye and an electron-accepting acidic substance as a main component, and coated with a desensitizing ink; A single-layer self-coloring pressure-sensitive recording sheet, characterized in that the layer contains a compound represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R_1 and R_2 represent integers having 4 to 12 carbon atoms.) 2. Claim 1, wherein the electron-accepting acidic substance is an organic acidic substance. Single-layer self-coloring pressure-sensitive recording sheet.