JPH115363A - Developing color ink, method for producing the same, and carbonless pressure-sensitive copying paper using the same - Google Patents

Abstract

(57) [Problem] To provide a color-developed ink having excellent color developability and good printability, a method for producing the same, and a carbonless pressure-sensitive copying paper printed with the color developable ink having good color developability. SOLUTION: When the content of the organic developer is 70% by weight, 40%.
The viscosity at 10 ° C. is 10 to 1000 poise, preferably 2
A color-developing ink characterized in that the color is 0 to 100 poise.
As the organic solvent for dissolving the organic developer, the carbon number is 1 to 1.
A fatty acid ester composed of a lower alcohol of 4 and a fatty acid having 12 to 16 carbon atoms and a fatty acid ester composed of a polyhydric alcohol having 2 to 6 carbon atoms and a fatty acid having 6 to 12 carbon atoms are preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color developing ink, a method for producing the same, and a carbonless pressure-sensitive copying paper using the same. More specifically, the present invention relates to a color developing ink suitable for letterpress or offset printing and having good color-forming ability, a method for producing the same, and a carbonless pressure-sensitive copying paper using the same.

[0002]

2. Description of the Related Art In general, carbonless pressure-sensitive copying paper is formed by coating microcapsules containing an oil in which a substantially colorless electron-donating color former (hereinafter referred to as a color former) is dissolved on the back surface of a support. It consists of an upper paper and a lower paper in which an electron-accepting solid acid (hereinafter referred to as a color developer) is applied on the surface of a support, and these two kinds of coating layers are overlapped so as to face each other and a ball-point pen or The microcapsules in the pressurized area are broken by the mechanical pressure of a typewriter, etc., and the oil in which the color former has been dissolved is transferred to the color developer layer, and the color developer reacts with the color developer to cause a color reaction. In this case, it is possible to obtain a record of simultaneous copying, and use a medium sheet having a function as an upper sheet and a lower sheet by providing a developer layer and a color former layer on the front and back surfaces of the support, respectively. It is possible to increase the number of copies . These carbonless pressure-sensitive copy papers are mainly used as copy office paper, slips, and forms.

[0003] Generally, the lower sheet and the middle sheet are coated with a color developer layer on the entire surface of the support, and in portions where copying color development is not desired, the color development reaction between the color developer and the color developer is prevented or reduced. It is necessary to print a desensitizing ink using a desensitizing agent having an effect of causing the printing and printing, and the cost and raw materials of two steps of coating and printing are required, which is very uneconomical. For this reason, it has been conventionally practiced to partially print the developed color ink only on the surface of the upper paper or on the plain paper only at the portion where copying and coloring is required to substitute for the middle paper or the lower paper.

[0004] Most of the developing color inks for practical use are those for a flexographic printing system using a low-boiling organic solvent, but have problems in safety or hygiene such as flammability, explosiveness and poisoning. Had. In contrast, JP-A-51-68307, JP-A-51-80410, and JP-A-51-80410
-94308, 54-89816, 54-94
No. 910, No. 54-148606, No. 55-3882
Nos. 6, 55-38826, 59-33369, and the like disclose a relief ink for offset printing or offset printing.

[0005] Of these printing methods, the one most commonly used in the printing industry at present is offset printing.
It is desirable that the printing of the developed ink can be performed by this method.
The present inventors have disclosed in Japanese Patent Application Laid-Open No. Hei 7-26184, an electron accepting organic color developer (hereinafter, referred to as an organic color developer) in a low-boiling-point solvent with respect to this method for producing a color developing ink for offset printing. An organic solvent for dissolving a developer is added thereto, mixed, and then the low-boiling solvent is distilled off to obtain an organic developer solution. A method of mixing or compatibilizing the components, kneading and forming an ink was disclosed.

However, when the developed ink obtained by this method is printed and used as a carbonless pressure-sensitive copying paper, the printability by the offset method is insufficient or a sufficient color density cannot be obtained. In some cases, further improvement has been required for these.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a color-developing ink having good color developability as a carbonless pressure-sensitive copying paper and good printability as a color-developing ink, and a process for producing the same.
Further, it is an object of the present invention to provide a carbonless pressure-sensitive copying paper excellent in color developing property obtained by printing the developed ink.

[0008]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve these problems, and as a result, have developed an organic developer, an organic solvent for dissolving the developer and a pigment containing a pigment as a main component. The viscosity of the organic developer solution dissolved in the organic solvent for dissolving the developer such that the ratio of the organic developer is 70% by weight is 10 to 1000 poise at 40 ° C., preferably 20 to 100 poise. As a result, the above problem could be solved.

By using a fatty acid ester composed of a lower alcohol having 1 to 4 carbon atoms and a fatty acid having 12 to 16 carbon atoms as the organic solvent for dissolving the developer, it is possible to obtain a desired developing ink. did it.

[0010] Further, by using a fatty acid ester comprising a polyhydric alcohol having 2 to 6 carbon atoms and a fatty acid having 6 to 12 carbon atoms as an organic solvent for dissolving the color developer, a desired color developing ink is obtained. I was able to.

By using a polyvalent metal salt of a salicylic acid derivative as the organic color developer, it was possible to obtain a color developing ink having particularly excellent color-developing properties.

An organic developer is synthesized in a low boiling solvent, an organic solvent for dissolving the developer is added thereto, mixed, and then the organic developer containing the organic developer obtained by distilling off the low boiling solvent is obtained. The viscosity at 40 ° C. when the rate is 70% by weight is 10 to 1000
Pois, preferably 20 to 100 poise, in an organic developer solution, an ink component other than the organic developer solution is mixed or compatible with each other, and kneaded to form an ink. Could be manufactured.

The resulting color ink is printed on the support surface (the surface not coated with the color-encapsulating microcapsules) of the carbon-free pressure-sensitive copying paper or high-quality paper by printing. A carbonless pressure-sensitive copying paper having excellent coloring properties was obtained.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The developer ink of the present invention, a method for producing the same, and a carbonless pressure-sensitive copying paper using the same will be described in detail below.

The organic developer solution used in the present invention has a viscosity of 40%.
The viscosity at ° C. is 10 to 1000 poise, preferably 20 to 100 poise when the organic developer content is 70% by weight. The organic developer content of the organic developer solution used in the production of the developer ink does not need to be 70% by weight, but an organic developer in which the organic developer can be dissolved at a concentration of 70% by weight or more. It is necessary to use an organic developer solution using a coloring agent and an organic solvent for dissolving the developer.

What is most necessary to enhance the color developing ability of the color developing ink is to increase the content of the organic color developing agent in the ink as much as possible. It is necessary to use an organic developer solution having suitable fluidity.

When the organic developer content is 70% by weight and at 40 ° C.
When an organic developer solution having a viscosity of more than 1000 poise is used, it is not possible to mix an organic developer having sufficient color developing properties into the ink. Therefore,
Only a color-developing ink having a low coloring ability can be obtained.

Further, when the organic developer content is 70% by weight,
The viscosity of less than 10 poise at 40 ° C. is often caused by using a low molecular weight organic solvent or a highly polar organic solvent. In such a case, the organic solvent has high volatility at room temperature, Microcapsules used for carbon pressure-sensitive copying paper can be broken, capsule oil contained can be easily extracted, solvent components can easily ooze out of the printed part, and stains other than the printed part may occur. A problem such as dropout is likely to occur, and it is not possible to obtain a preferable color developing ink.

As the organic solvent for dissolving a color developer used in the present invention, a non-volatile organic solvent capable of dissolving an organic color developer at a concentration of 70% by weight or more and obtaining a stable organic color developer solution at room temperature. Can be used, for example, can be appropriately selected from fatty acid esters, aliphatic ethers, higher alcohols, halogenated hydrocarbons, aromatic hydrocarbons, and the like. Examples of the solvent include the following solvents.

The fatty acid ester used in the present invention comprising a lower alcohol having 1 to 4 carbon atoms and a fatty acid having 12 to 16 carbon atoms includes isopropyl laurate, butyl laurate, methyl myristate, ethyl myristate. , Isopropyl myristate, butyl myristate,
Examples thereof include methyl palmitate, ethyl palmitate, isopropyl palmitate, butyl palmitate and the like.

Other fatty acid esters having a total carbon number of 12 or less have high hydrophilicity and are not suitable for offset printing. When the total number of carbon atoms exceeds 20, the viscosity of the fatty acid ester increases, and the viscosity of the organic developer solution increases due to the decrease in the dissolving power. Can not be enhanced.

The polyhydric alcohol of a fatty acid ester comprising a polyhydric alcohol having 2 to 6 carbon atoms and a fatty acid having 6 to 12 carbon atoms used in the present invention includes ethylene glycol, propylene glycol, butylene glycol and the like. Glycols, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, etc.
Examples of the fatty acid having 12 or less carbon atoms include caproic acid, caprylic acid, 2-ethylhexanoic acid, capric acid, and lauric acid. Representative compounds include propylene glycol monocaprylate and propylene glycol dicaprylate. , Propylene glycol didecanoate, glyceryl tri-2-ethylhexanoate, tri (capryl,
Glyceryl (capric acid), trimethylolpropane tri-2-ethylhexanoate and the like can be used.

When a fatty acid having 5 or less carbon atoms is used, the hydrophilicity is so high that it is not suitable for offset printing. The viscosity of the solution increases,
The content of the organic developer in the developer ink cannot be increased. In addition, when a polyhydric alcohol having 7 or more carbon atoms is used, the viscosity of the organic solvent for dissolving the developer itself increases, and the ability to dissolve the organic developer tends to decrease.
Polyhydric alcohols having 2 to 6 carbon atoms are preferred.

If necessary, two or more of these organic solvents for dissolving the developer may be used in combination to adjust the viscosity. Also, neopentyl glycol diacrylate,
Used in combination with monomers such as pentaerythritol triacrylate and trimethylolpropane triacrylate,
It can be a UV-curable developing ink.

The color-developing ink of the present invention contains an organic color developer, an organic solvent for dissolving the color developer and a pigment as main components, and other components such as resins used in general printing inks. , An ink solvent, an antioxidant, an ultraviolet absorber, a wax, a fluorescent dye, a show-through preventing agent, a drying accelerator, and the like can be appropriately used.

As an organic developer, a phenol resin, a salicylic acid derivative or a polyvalent metal salt thereof, and the like are conventionally known. Examples of the phenol resin include a p-phenylphenol formaldehyde resin and a p-cumylphenol formaldehyde resin. , P-butylphenol formaldehyde resin, p-octylphenol formaldehyde resin and the like and polyvalent metal salts thereof.

As salicylic acid derivatives, 3,5-di-
tert-butylsalicylic acid, 3,5-di- (α-methylbenzyl) salicylic acid, 3-cyclohexyl-5
(Α, α-dimethylbenzyl) salicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl) salicylic acid, JP-A-63-186729 and JP-A-63-254124;
No. 63-289017, No. 64-56724, No. 6
4-77575, JP-A-1-133780, 1-
Nos. 182317, 2-160815 and 4-892
The salicylic acid resin disclosed in each of the publications such as No. 74 can be used. From the viewpoint of color development, a salicylic acid derivative is preferably used, and particularly preferably a polyvalent metal salt.

Examples of polyvalent metals include calcium, magnesium, aluminum, nickel, copper, zinc, tin,
There are barium and the like, and among these, it is most preferable to use it as a zinc salt.

These organic color developing agents are solid when used alone. Conventionally, when forming a color developing ink, a powdered organic color developing agent was dissolved in an organic solvent. Is difficult to dissolve at a high concentration, and in particular, since an organic developer of a salicylic acid derivative is hardly dissolved in an organic solvent, it has been difficult to obtain a high-concentration organic developer solution.

However, by using a method of synthesizing an organic developer in a low-boiling solvent and distilling and replacing the low-boiling solvent with the organic developer for dissolving the developer used in the present invention, a high-concentration solvent can be easily obtained. Was obtained, and a developing ink having an increased organic developer content was obtained.

The content of the organic color developer in the color development ink is required to be 30% by weight or more from the viewpoint of color development, and preferably 4% by weight.
0% by weight or more.

Examples of the low boiling solvent used in the polymerization of the organic developer include n-hexane, n-heptane,
aliphatic hydrocarbons such as 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-dichloroethane;
Halogenated hydrocarbons such as 2-trichloroethane, carbon tetrachloride, chloroform and monochlorobenzene, organic acids such as acetic acid and propionic acid, ketones such as acetone and methyl ethyl ketone, other benzene, toluene, xylene, carbon disulfide, nitromethane, Acetonitrile, tetrahydrofuran and the like can be mentioned, and a solvent inert to the reaction is selected and used.

As a method for polymerizing an organic color developer, a conventional method can be applied.
Nos. 37713 and 64-56724, JP-A-1-13
Nos. 3,780, 2-653, 4-129789, and the like. By applying these methods, an organic developer in which an organic developer is dissolved in a low-boiling solvent is used. A colorant solution can be obtained. The concentration of the solid content of the organic developer during the polymerization reaction is not particularly limited, but the synthesis reaction is usually performed at a concentration of about 30 to 70% by weight.

In the present invention, the organic developer content of the organic developer solution after replacement with the organic solvent for dissolving the developer is not particularly limited, but the organic developer solution after replacement is not limited. May be determined based on the ease of handling and the relationship of the ink composition with other ink components. Usually, the concentration is preferably about 60 to 80% by weight.

Examples of the pigment used in the present invention include titanium oxide, calcium carbonate, aluminum hydroxide, alumina white, barium sulfate, zinc oxide, kaolin, activated clay, and the like. , Preferably 5 to 30% by weight.

Examples of resins as other components include rosin-modified phenolic resin, rosin-modified maleic resin, petroleum resin, hydrogenated petroleum resin, polyamide resin, and butanol-modified amino resin.

In the case of a photo-curable color developing ink, a polyhydric alcohol (meth) acrylate, epoxy (meth) acrylate, rosin-modified epoxy (meth) acrylate, polyester (meth) acrylate, polyurethane (meth) ) Acrylate, polyether (meth)
(Meth) acrylate-based prepolymers such as acrylate and alkyd (meth) acrylate.

The color developing ink of the present invention is prepared by mixing or compatibilizing a pigment and, if necessary, a resin and an additive component with the organic color developer solution, and using a required three-roll mill or the like to prepare the meat. Can be manufactured.

The color developing ink of the present invention is printed on a support by various offset type or letterpress type printing machines. The amount of the developed ink is 0.5 to 5 g as ink.
/ m ² is preferred.

The carbon-free pressure-sensitive copying paper obtained by printing on the surface of the support using the color developing ink of the present invention has excellent color-forming ability and little discoloration of the color image with time. In addition, there is no phenomenon that the color image comes off to the back surface of the support, and it can be used as an excellent carbonless pressure-sensitive copying paper for partial color development.

[0041]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.
In the examples, “parts” means “parts by weight”.

[Preparation of salicylic acid-based developer solution] 138 parts of salicylic acid was added to 346 parts of toluene, heated to 100 ° C, and 9.5 parts of methanesulfonic acid was added with stirring. Further, 208 parts of styrene was gradually added, and the reaction was continued until the residual styrene became 0.05% or less. Next, 63 parts of basic zinc carbonate was added little by little, and the mixture was stirred so as to be uniform to obtain a toluene solution of a zinc salt of a salicylic acid-styrene reactant. An organic solvent for dissolving the color developer is added to the toluene solution of the zinc salt of the salicylic acid-styrene reactant obtained, and the mixture is heated under reduced pressure to distill and remove the toluene. The salicylic acid having an organic color developer content of 70% by weight is obtained. A solution of the styrene reactant zinc salt was obtained. The salicylic acid-styrene reactant zinc salt had a main component as a result of measurement by NMR,
It was confirmed to be zinc 3,5-di- (α-methylbenzyl) salicylate (hereinafter, this developer is referred to as a salicylic acid-based developer).

[Preparation of phenol-based developer solution] 850 parts of p-phenylphenol, 112 parts of paraformaldehyde having a purity of 80%, 8.5 parts of p-toluenesulfonic acid,
800 parts of benzene are placed in a glass flask and heated with stirring. The distilling benzene and water azeotrope are cooled and condensed and separated. The aqueous layer is separated and benzene is refluxed in the flask. When the distillation of water stops, the reaction is stopped, an organic solvent for dissolving the color developer is added, and the mixture is heated under reduced pressure to remove benzene by distillation. The content of the organic color developer is 70% by weight of p-phenylphenol formaldehyde. A resin solution was obtained (hereinafter, this developer is referred to as a phenol-based developer).

[Preparation of Developing Ink] Using a salicylic acid-based and phenol-based organic developer solution, the developing ink was prepared by kneading with a three-roll mill according to the following basic recipe. Organic developer solution 70 parts Rosin-modified phenolic resin 10 parts Titanium oxide (trade name: Taihae CR93, manufactured by Ishihara Sangyo Co., Ltd.) 20 parts If the viscosity of the developer is too high in the above formulation, the organic developer The fluidity of the ink was adjusted by adding an appropriate amount of an organic solvent for dissolving the developer used for dissolution.

[Evaluation Test Method for Developed Ink] The obtained developed ink was evaluated by the following method. 1) Ink fluidity The ink fluidity when kneaded with the above basic formula was determined.
Those that do not require the addition of an organic solvent for dissolving the developer
な る indicates that the fluidity is improved by adding a small amount, △ indicates that a relatively large amount of addition is required, and x indicates that a considerably large amount of addition is required. 2) Color development The color development of carbon-free pressure-sensitive copy paper was evaluated using an RI tester (Meiji Seisakusho) on a high quality paper (basis weight 40 g / m ² ) with approximately 1.2 g / m ² of developed ink. And NCR paper (manufactured by Mitsubishi Paper) was superimposed on the obtained carbonless pressure-sensitive copying paper, and the color density after printing with a typewriter was evaluated as follows: ○: good, Δ: slightly good, ×: Judged as defective. 3) Color-developing stain The color-developing stain of the carbonless pressure-sensitive copying paper obtained in 2) is caused by bleeding of the color-developed ink component on the back surface of the coloring section one day after printing on the typewriter of the carbonless pressure-sensitive copying paper obtained in 2). The extent of was examined. Colored stains were given when no coloring was found on the back surface, Δ was given when the stain was slightly stained but did not hinder practical use, and X was given when the stain was severe. 4) Offset Printing Suitability The obtained developer ink was subjected to offset printing printing using a form printing machine (offset form rotary press MVF, manufactured by Miyakoshi Co., Ltd.) to evaluate the offset printing suitability.
も の indicates that the offset plate surface was less likely to be stained, Δ indicates that the stain was slightly generated, but did not hinder practical use, and X indicates that the stain was severely generated.

Examples 1 to 8 and Comparative Examples 1 to 3 Salicylic acid-based developer solutions were prepared using the organic solvents for dissolving the developers shown in Table 1. The viscosity of the obtained organic developer solution at 40 ° C. was measured and is shown in Table 1. In Comparative Example 3 using No. 5 solvent (manufactured by Nippon Oil Co., Ltd.) generally used for printing inks, the organic developer was solidified, and an organic developer solution could not be obtained.

[0047]

[Table 1]

Using the salicylic acid-based developer solutions obtained in Examples 1 to 8 and Comparative Examples 1 and 2, a color developing ink was prepared.
An evaluation test was performed by the above method. The results are shown in Table 2.

[0049]

[Table 2]

When the viscosity of the organic developer solution is 2 at 40 ° C.
The ink fluidity and color development of Examples 3, 4, and 5 having 0 to 100 poise were good. The viscosity of the organic developer solution is 1
In Examples 1, 2, 7, and 8 in which the value was more than 00 poise and 1,000 poise or less, there was no problem in practical use, but the results were slightly inferior in terms of ink fluidity or coloring. In Comparative Example 1 in which the viscosity of the organic developer solution exceeded 1000 poise, both the ink fluidity and the color developing properties were insufficient. In Example 6 in which the viscosity of the organic developer solution was low, the back surface of the coloring portion was slightly stained, and in Comparative Example 2 in which the viscosity of the organic developer solution was less than 10 poise, the back surface of the coloring portion was considerably poor.

The developed inks obtained in Examples 1 to 8 and Comparative Examples 1 and 2 were evaluated for offset printing suitability. As a result, the developed inks of Examples 2 to 5, 8 and Comparative Example 1 were good. Examples 1, 6 and 7 showed slightly good print suitability, but the color developing ink of Comparative Example 2 had severe stains on the offset plate surface and was insufficient in print suitability.

Example 9 A phenol-based developer solution was prepared using the organic solvent for dissolving the developer shown in Table 3. The viscosity at 40 ° C. of the obtained organic developer solution was measured, and the results are shown in Table 3. Using the obtained phenol-based developer solution to produce a developer ink,
An evaluation test was performed. The results are shown in Table 4.

[0053]

[Table 3]

[0054]

[Table 4]

Comparing Example 4 with Example 9, the use of a salicylic acid-based developer as an organic color developer has better ink fluidity and color development than the case of using a phenol-based developer. Met.

[0056]

As described above, according to the present invention, an organic developer having a viscosity at 40 ° C. of 10 to 1000 poise, preferably 20 to 100 poise when the content of the organic developer is 70% by weight. By using the colorant solution, it is possible to obtain a color developing ink having good ink fluidity and excellent color developability and printability. As an organic solvent for dissolving an organic developer, a lower alcohol having 1 to 4 carbon atoms and 12 to 12 carbon atoms are used.
Fatty acid ester consisting of 16 fatty acids, having 2 to 2 carbon atoms
By using a fatty acid ester comprising a polyhydric alcohol of 6 and a fatty acid having 6 to 12 carbon atoms, it is possible to obtain a developed ink having good ink fluidity, excellent color developability, and excellent printability. Further, by printing using these developed inks, it was possible to obtain a carbonless pressure-sensitive copying paper having excellent coloring properties and less coloring stains.

Claims (9)

[Claims] 1. An electron-accepting organic color developer which is colored by reacting with an almost colorless electron-donating color former, an organic solvent for dissolving the organic color developer, and a color development comprising a pigment as a main component. In the ink, when the organic developer is dissolved in the organic solvent for dissolving the developer so that the content of the organic developer is 70% by weight, the viscosity is 10 to 100 at 40 ° C.
A color developing ink characterized by having 0 poise. 2. The viscosity of an organic developer dissolved in an organic solvent for dissolving a developer so that the content of the organic developer is 70% by weight is 20 to 100 poise at 40 ° C. 2. The color-developed ink according to 1. 3. An organic solvent for dissolving a developer, wherein the organic solvent has a carbon number of 1 to 3.
The color developing ink according to claim 1, which is a fatty acid ester comprising a lower alcohol of No. 4 and a fatty acid having 12 to 16 carbon atoms. 4. An organic solvent for dissolving a color developer having a carbon number of 2 to 2.
The color developing ink according to claim 1, which is a fatty acid ester comprising a polyhydric alcohol of 6 and a fatty acid having 6 to 12 carbon atoms. 5. The color developing ink according to claim 1, wherein the electron accepting organic color developing agent is a polyvalent metal salt of a salicylic acid derivative. 6. An electron-accepting organic color developer is synthesized in a low-boiling solvent, an organic solvent for dissolving the color developer is added thereto, and mixed.
Thereafter, the viscosity at 40 ° C. when the developer content is 70% by weight obtained by distilling off the low boiling point solvent is 10 to 10.
A method for producing a color developing ink, comprising mixing or compatibilizing ink components other than the organic color developing solution with an organic color developing solution having a poise of 1000 poise, and kneading to form an ink. 7. 40 ° C. when the developer content is 70% by weight
7. The method for producing a color developing ink according to claim 6, wherein an organic color developer solution having a viscosity of 20 to 100 poise is used. 8. The method of claim 6, wherein the organic solvent for dissolving a developer is the organic solvent for dissolving a developer according to claim 3 or 4. 9. A carbonless pressure-sensitive copying paper obtained by printing the color developing ink according to claim 1 on the surface of a support.