JPH02261869A - Color development retarder in correcting ink for thermosensible paper - Google Patents

Abstract

PURPOSE:To prepare a color development retarder giving a correcting ink which is excellent in the aging stability, fast drying properties, and correcting capability and useful for thermosensible paper by compounding a modified acrylic resin obtd. by the copolymn. of two specific acrylate monomers. CONSTITUTION:An acrylate monomer of formula I (wherein R1 is H or methyl; and R2 is a 2C or higher hydrocarbon group optionally substd. by a hydroxyl group) (e.g. 2-hydroxyethyl methacrylate) and an amino acrylate monomer of formula II (wherein R3 is H or methyl; and R4 is alkyl) (e.g. monoethylaminoethyl methacrylate) are copolymerized to give a modified acrylic resin, which is mixed, as a color development retarder, with an org. solvent (e.g. cyclohexane), a white pigment (e.g. titanium oxide), etc., to give a suitable correcting ink for thermosensible paper.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel color development inhibitor for thermal paper correction inks. More specifically, when the present invention is used as a compounding component of a correction ink composition, particularly a thermal paper correction ink composition, the composition has good stability over time and prevents pigment sedimentation and thickening over a long period of time. The present invention relates to a color development inhibitor for thermal paper correction ink that does not cause floating, has quick drying properties, and has excellent correction ability for thermal paper.

Conventional technology Conventionally, as ink for correcting typographical errors made with ballpoint pens, felt-tip pens, dry copying (electrostatic copying, PPC), typewriters, etc., oil-based inks for correcting typographical errors using water-based inks have been used.
A water-based type for correcting typographical errors using oil-based ink and a dual-use type that can correct typographical errors with any type of ink are known.

Among these correction inks, dual-use correction inks are particularly advantageous because they can correct any type of ink, regardless of the nature of the ink to be erased.

This dual-use correction ink usually has an organic solvent with a relatively low boiling point, a white pigment such as titanium dioxide, and an organic solvent-soluble binder resin as its main components, and if necessary, various additives such as wetting and dispersing agents, sedimentation prevention agents, etc. It is prepared by blending agents, coating film modifiers, coloring pigments, etc. Such dual-use correction inks have so far been used, for example, correction inks made of organic solvents, white pigments, and polyvinyl alkyl ether (Japanese Patent Publication No. 42952/1983), white pigments, paraffinic solvents, and naphthenic solvents. , and a correction fluid containing a binder soluble in the solvent, a nonionic surfactant, a cationic quaternary ammonium salt, etc.
42075) and the like have been proposed.

By the way, the main properties required of correction ink include, for example, excellent stability over time, such as resistance to pigment settling and thickening phenomena, and quick drying properties.
One example of this is that the formed coating film has an excellent correction function.

However, it cannot be said that the dual-use correction inks described above can necessarily satisfy all of the main properties required of these correction inks, and are still insufficient, especially for thermal paper. The current situation is that it cannot be said that it has the ability to make corrections.

In addition, the acrylic resin used in general room-temperature-drying paints is normally one that is soluble in toluene, xylene, butylene acetate, ethyl acetate, etc., and typical polymers such as methyl methacrylate-butyl acrylate are used. It will be done. In addition, acrylic ester resins and methacrylic ester resins that dissolve in low polarity solvents such as cycloparaffinic solvents and paraffinic solvents can also be used as binder resins.

However, although these copolymers and ordinary (meth)acrylic acid ester resins used as binder resins can be expected to produce a certain degree of dry film when used as a correction liquid component, they lack the correction function for thermal paper, and It is inevitable that it will react with the dye inside and become colored. The cause of this coloring is the coloring reaction accompanying the ring opening of the lactone ring of the leuco dye, which is the coloring agent in the thermal paper, especially when the acrylic ester resin has a carboxylic acid functional group. This is thought to be because this acts as a color developer, making color development more likely.

Therefore, in order to prevent such coloring, a method has been proposed in which amines, polyethers, etc. are added to the correction fluid as coloring inhibitors (Japanese Patent Laid-Open No. 63-142075, Japanese Patent Laid-Open No. 63-142077). Publication No.).

However, many of these color development inhibitors act as cationic surfactants or nonionic surfactants, and depending on the amount added, many of them act as flocculants for pigments, and they also act as non-volatile substances. Therefore, if the amount added is large, the functionality of the coating film will deteriorate, and there will be disadvantages such as a tendency to stick or yellowing when rewriting or reprinting after correction.

Problems to be Solved by the Invention The present invention overcomes the drawbacks of such conventional color development inhibitors for correction inks, and when used as a compounding component of correction ink compositions, particularly thermal paper correction ink compositions, The composition has excellent stability over time and quick-drying properties, and has the ability to correct lines drawn by various writing instruments and dry copies, as well as satisfactory correction ability especially for thermal paper. This was made for the purpose of providing a color development inhibitor.

Means for Solving the Problems The present inventor has conducted various research to develop a color development inhibitor for thermal paper correction ink that has these desirable properties. It was discovered that a resin is suitable for the purpose, and the present invention was completed based on this knowledge.

That is, the present invention provides copolymerized modified acrylic acid CH,
-C-C0OR,...(1) (R8 in the formula is a hydrogen atom or a methyl group, R2 has 2 carbon atoms
Indicates a hydrocarbon group that may be substituted with the above hydroxyl group) and an acrylic ester monomer represented by -large amount% formula%) (in the formula, R8 is a hydrogen atom or a methyl group% R4 is an alkyl group) The present invention provides a color development inhibitor for thermal paper correction ink comprising a modified acrylic resin copolymerized with an amino group-containing acrylic monomer represented by the following formula.

The present invention will be explained in detail below.

The color development inhibitor of the present invention comprises the above-mentioned large amount (I) of the acrylic ester monomer and the above-mentioned large amount (Ii) of the amylyl resin.

This modified acrylic resin has a large amount of % formula % (RI in the formula is a hydrogen atom or a methyl group, R2 is a carbon number of 2
Indicates a hydrocarbon group which may be substituted with the above hydroxyl group). It is produced by copolymerizing with an amino group-containing acrylic monomer represented by

Examples of the acrylic ester monomer include ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, butyl acrylate, butyl methacrylate, inbutyl acrylate, inbutyl methacrylate, pentyl methacrylate, hexyl acrylate, heptyl methacrylate,
Examples include octyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, and 2,3-dihydroxypropyl methacrylate.

In addition, the amino group-containing acrylic monomer is usually used in an amount of 5 to 25% by weight based on the total amount of monomers, and examples of the monomer include monoethylaminoethyl methacrylate, monomethylaminoethyl methacrylate, monoethylaminoethyl acrylate, and monomethylaminoethyl acrylate. Examples include acrylate.

The color development inhibitor of the present invention can be used to form a correction ink composition, particularly a thermal paper correction ink composition, by blending an organic solvent with a white pigment such as titanium oxide.

Examples of this organic solvent include cyclohexane, methyl Preferred are cycloparaffinic solvents such as cyclohexane, ethylcyclohexane, and dimethylcyclohexane, and paraffinic solvents such as n-hexane, n-heptane, isoheptane, n-octane, and isooctane. Each of these solvents may be used alone or in combination of two or more, and other solvents such as benzene may be added to these solvents to the extent that the above-mentioned properties as a solvent are not impaired. , aromatic hydrocarbon solvents such as toluene, xylene, and ethylbenzene, ether solvents such as 1,4-dioxane and n-butyl ether hydro7rane, and ketones such as methyl ethyl ketone, methyl-〇-propyl ketone, methyl isobutyl ketone, and cyclohexanone. System solvent, 1.1.
It is also possible to add chlorinated hydrocarbon solvents such as 1-trichloroethane.

In addition, as a titanium oxide white pigment, high solids (
Heavy-coat type titanium dioxide, which can exhibit high opacity in high-concentration) systems, is preferred, and rutile type IV titanium dioxide, which uses a large amount of oxides such as aluminum and silicon as the main treatment agent, is particularly suitable, but general-purpose titanium dioxide is preferred. Type: Rutile type L
There is no problem in using titanium dioxide of type 2.3 or anatase type titanium dioxide. Such titanium oxide can be easily obtained as a commercial product, such as JR-800, JR-801, JR-
600, JR-701 (manufactured by Teikoku Kako Co., Ltd., product name), R-
7801R-780-2, R-830, R-930, R
-550 (manufactured by Gosoku Sangyo Co., Ltd., product name), R-900, R-
933 (manufactured by DuPont, trade name) and the like. Furthermore, other pigments such as fine silica powder, calcium carbonate, white carbon, talc, clay, plastic pigment (hollow resin), etc. can be used in combination with the titanium oxide-based white pigment as desired. In this case, the other pigments are preferably used in an amount of 30% by weight or less based on the total amount with the titanium oxide white pigment.

Regarding the content ratio of each component in the correction ink composition, the organic solvent is 30 to 60% by weight, the titanium oxide white pigment is 25 to 60% by weight, and the modified acrylic resin is 3 to 60% by weight.
The composition preferably contains various additives commonly used in dual-use correction inks, such as dispersants, anti-settling agents, and film-modifying agents, if desired. Resins (for example, natural resins, aliphatic petroleum resins, aromatic petroleum resins), etc. can be added within a range that does not impair the purpose of the present invention.

The correction ink composition uses an organic solvent, a titanium oxide white pigment, a modified acrylic resin, and various additives added as desired in a predetermined ratio, and mixes and disperses them using a mixing and dispersing machine, such as a ball mill, or a colloid. mill, attritor,
It is prepared by uniformly mixing and dispersing using a sand mill, bead mill, etc.

Effects of the Invention When the color development inhibitor for correction ink of the present invention is used as a compounding component of an ink composition for thermal paper correction, the coloring component does not settle, thicken, or float over a long period of time, etc.
It has excellent stability over time, has quick drying properties, maintains a binder effect, and exhibits the remarkable effect of having excellent correcting ability without causing discoloration or bleeding when correcting thermal paper.

Example Next, the present invention will be explained in more detail with reference to Examples.

Each formulation example is a correction ink composition containing a color development inhibitor for correction ink made of an acrylic resin composed of each of the seven mer units shown in Table 1, showing the composition components and their weight proportions. It is.

Further, the characteristics of the correction ink compositions in Examples were tested as follows.

The correction ink composition of each example was applied with a brush to thermal recording paper from each manufacturer printed using a personal word processor.

Bleeding phenomenon (embossed characters) in the printed and non-printed areas (white background) of each dry-formed correction ink composition coating film
And discoloration was visually observed and evaluated.

Evaluation method: Good: The printed area is completely hidden, and no bleeding phenomenon or discoloration is observed. Poor: The printed area stands out on the surface of the repaired coating, and reddish-black discoloration is observed over the entire coating, including the non-printed area. Example 1 Table Composition Composition R-933 (manufactured by DuPont, methylcyclohexane ethylcyclohexane modified acrylic resin A content weight % titanium dioxide) 40.00 30.00 21.00 8.00 Prelife A-208F (Daiichi) Manufactured by Kogyo Seiyaku Co., Ltd., Formulation Example 2 Dispersant) 1.00 Composition JR-801 (manufactured by Teikoku Kako Co., Ltd., Methylcyclohexane Ethylcyclohexane Modified Acrylic Resin B Lactimon (manufactured by BYK, Formulation Example 3) Weight % Titanium dioxide) 42.00 30.00 19.50 8.00 Wetting and dispersing agent) 0.50 Composition Component Weight% R-7
80 (manufactured by Gosoku Sangyo Co., Ltd., titanium dioxide) 45.00 Methylcyclohexane 44.50 Modified acrylic resin c a, o.

Fine silica powder 1.00 First formulation example 4 Composition Ingredients Weight% JR-
600 (manufactured by Teikoku Kako Co., Ltd., titanium dioxide) 45.00
Methylcyclohexane 46.20 Acrylic resin D 8.00 Titacoat 5152 (manufactured by Nippon Soda Co., Ltd., titanate coupling agent) O, SO Examples 1 to 3, comparative examples Compositions according to each of the above formulation examples were ball milled. So 4
A correction ink composition was obtained by mixing and dispersing for 0 hours.

The composition thus obtained was applied to the printed surface of thermal paper of each manufacturer shown in Table 2, and its characteristics were tested.

The results are shown in Table 2.

From this Table 2, it can be seen that the comparative example using an acrylic resin having an acrylic acid monomer unit caused a reddish-black discoloration;
In contrast, when using a modified acrylic resin containing a large amount (II) of amino group-containing acrylic acid monomer units, the printed surface is hidden in white, causing discoloration and bleeding. It turns out that the phenomenon is not observed.

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. There are acrylic ester monomers represented by the general formula ▲ (mathematical formula, chemical formula, table, etc.) (in the formula, R_3 is a hydrogen atom or a methyl group, and R_4 is an alkyl group). A color development inhibitor for thermal paper correction ink consisting of a modified acrylic resin copolymerized with a monomer.