JPS62243667A - Pigment ink composition for ball-point pen - Google Patents

Abstract

PURPOSE:The titled composition, obtained by further containing an unsaturated fatty acid salt in an ink composition consisting of a pigment, dispersing agent and aqueous medium, having smooth feeding of ink in starting to write and capable of smooth writing without skipping of describing lines even in continuous writing. CONSTITUTION:A composition obtained by further containing a salt, preferably water-soluble salt of an unsaturated fatty acid, preferably 9-39C, particularly oleic acid, linoleic acid, linolenic acid or ricinoleic acid in an ink composition consisting of a pigment, preferably carbon black, a dispersing agent, preferably polymer dispersing agent and an aqueous medium.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to ink for ballpoint pens, and more specifically, the present invention relates to an ink for ballpoint pens, and more specifically, a water-based ink consisting of a pigment 1 dispersant and an aqueous medium containing an unsaturated fatty acid salt. This allows the ink to flow smoothly at the beginning of writing, and there are no skipped lines even when writing continuously.

This invention relates to a water-based pigment ink composition for ballpoint pens that allows smooth writing.

(Prior art) Ballpoint pens have been very widely used as a type of writing instrument, and high-viscosity oil-based inks have been used for these ballpoint pens, but in recent years, inks with drying properties have been used. Superior water-based inks became widely used.

The coloring materials used in water-based inks are broadly classified into water-soluble dyes and pigments.Dye does not cause problems such as clogging at the pen tip, but it does not affect the light fastness of recorded materials. Many problems arise in sexuality. On the other hand, in the case of pigments,
Pigment inks have become widely used in recent years because they provide recorded matter with excellent light resistance and water resistance.

(Problem to be solved by the invention) Regarding water-based ballpoint pen inks, various additives have been developed and put into practical use for dye type inks, but for pigment type inks, the pigment itself, which is the coloring material, exists in the form of fine particles. ,
The surface activity is also large and shows a sharp contrast with dyes, and since the pigment is in the form of particles, it significantly accelerates the wear of the pole of a ballpoint pen, and also causes a lack of fluidity of the ink due to particle agglomeration.

Conventionally, ink for water-based ballpoint pens that use pigments, the ink itself lacks lubricity, so the pole does not rotate smoothly, and the ink ejected at the beginning of writing is insufficient. Lines may skip when writing, the writing may not feel smooth, or the ink discharge may be extremely reduced.Also, after long-term use, the pole seat may become worn out and the pole may become missing, causing the ink to deteriorate. It had the disadvantage that it became impossible to write on before it was consumed.

Therefore, although they have the water resistance and light resistance that are the characteristics of pigment inks, they are currently inferior in terms of practicality compared to dye inks.

As a result of intensive research, the present inventors aimed to improve such drawbacks and complete a water-based pigment ink composition for ballpoint pens that has excellent writing properties while fully retaining the characteristics of the pigment. In an aqueous pigment ink composition consisting of an aqueous medium,
The present invention was completed based on the finding that an aqueous pigment ink composition for ballpoint pens with sufficiently improved writability can be obtained by adding a salt of an unsaturated fatty acid.

(Means for Solving the Problems) That is, the present invention provides an aqueous pigment ink composition for a ballpoint pen, which further contains a salt of an unsaturated fatty acid in an ink for a ballpoint pen consisting of a pigment, a dispersant, and an aqueous medium. It is a thing.

To explain the present invention in detail, the pigment used in the present invention is
All conventionally known organic and inorganic pigments can be used, such as azo, phthalocyanine, quinacridone, anthraquinone, dioxazine, indigo/thioindigo, perinone/perylene, isoindorenone, azo-methineazo, etc. organic pigments, and inorganic pigments such as titanium oxide, iron oxide, and carbon black.

These pigments can be used either in powder form or in the form of an aqueous paste such as a filter cake, but it is preferable to use an aqueous paste from the viewpoint of ease of dispersion.

The content of the pigment in the pigment ink composition for ballpoint pens must be at a density sufficient to allow recorded matter to be identified, such as when it is used as an ink to read or recognize written or recorded information. Although necessary and not particularly specified, the amount preferably accounts for 3 to 30% by weight of the total composition.

In particular, carbon black pigment is the pigment used in black ink, which is the most commonly used writing and recording ink, but this pigment is usually difficult to disperse because of its strong polarity and extremely fine particles. However, it was considered to be a less stable pigment.

By using the additive according to the present invention, the dispersion stability in the ink was significantly improved, and it was possible to provide excellent writability, and it was possible to obtain a pigment ink composition for a ballpoint pen with excellent black color.

As the dispersant used in the present invention, any conventionally known pigment dispersant can be used, but particularly preferred are polymer dispersants. Polymer dispersants consisting of an oily moiety are particularly suitable.Such polymer dispersants can be roughly divided into condensation polymers and addition polymers, and any existing ones can be used. As for the preferable condensed type, for example, JP-A-60
There is a polyester-based dispersant described in Japanese Patent No. 26070, and addition polymer-based dispersants include addition polymers of monomers having α,β-ethylenically unsaturated groups. Particularly preferred are addition polymer-based dispersants, which are obtained from monomers forming lipophilic portions and monomers forming lignophilic portions.

The monomer forming the lipophilic portion of the dispersant is a conventionally known hydrophobic polymer that provides a lipophilic portion to a portion of the polymer dispersant, such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, etc. Alkyl esters of unsaturated carboxylic acids, cycloalkyl esters, arylalkyl (arylalk71) x stel, aryl (6y
yl) esters and aromatic vinyl compounds. More specifically, examples include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, etc. having 1 to 1 carbon atoms.
20 alkyl esters, cyclohexyl esters, benzyl esters, phenyl esters, etc., styrene, α-
These include methylstyrene and vinyltoluene.

Among the above, preferred are those having an alkyl group, a cycloalkyl group, an arylalkyl group, or an aryl group having 4 to 16 carbon atoms. The lipophilic portion of such monomers is about 10-93% by weight, preferably 30-90% by weight in the dispersant.

Also, what is the wood-loving part in the dispersant?

Contains any one of (a) an anionic lignophilic group and its aqueous medium-soluble salt, (b) a cationic lignophilic group and its aqueous medium-soluble salt, (c) a nonionic lignophilic group, or a mixture thereof. It is a polymer part.

Examples of anionic wood-philic groups include carboxyl groups, sulfonic acid groups, sulfuric ester groups, phosphoric ester groups, etc., or their alkali metal salts, such as sodium salts, potassium salts, ammonium salts, and lower amines. Salts, e.g. mono-, di- or tri-carbon number 1-3
salts of alkylamines, alkanolamines, alkylalkanolamines, morpholines, alkylmorpholines, etc., and calcium salts of sulfonates.

Cationic wood-philic groups include primary, secondary, tertiary amino groups, quaternary ammonium groups, and pyridinium groups, including 7 primary amino groups and substituents having 1 to 4 carbon atoms. Secondary and tertiary amine groups, quaternary ammonium groups and their salts of lower fatty acids.

For example, salts of formic acid, acetic acid, propionic acid and salts of inorganic acids such as hydrochloride, bromate, sulfonate, sulfuric acid alkyl ester salt, phosphate, etc.

Examples of nonionic wood-philic groups include hydroxyl groups, carboxamide groups, ether groups, etc., or those having these groups, such as hydroxyethyl groups, glyceryl groups, polyether glycol groups, and carboxylic acid amide groups.

Furthermore, examples of the seven polymers forming the above-mentioned wood-loving part include: (a) Anionic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid; dibasic acids such as the above-mentioned itaconic acid; monoamide monocarboxylic acids;
Hydroxyethyl esters and phosphoric acid esters of the above-mentioned unsaturated carboxylic acids, hydroxypropyl esters; Sulfoethyl esters and sulfoethylamides of the above-mentioned unsaturated carboxylic acids: Styrene sulfonic acid and the above-mentioned aqueous medium-soluble salts thereof. .

Also, heptamers having a group that can be converted into the above-mentioned anionic group after polymer formation, for example, heptamers having a group such as an acid anhydride or a lower alkyl ester, are also used.

(b) Aminoalkanol esters and N-alkylaminoalkanol esters of the unsaturated carboxylic acids mentioned in (a) as cationic ones.

N,N-dialkylaminoalkanol ester, N,
N,N-trialkylammonium alkanol ester, γ-amino-β-hydroxy-n-propyl ester, γ-(N-fulkylamino)-β-hydroxy-n
-propyl ester, γ-(N,N-dialkylamino)-β-hydroxy-n-7'pyl ester, N,N
- dialkylaminoalkylamides, etc., and the above-mentioned aqueous medium-soluble salts thereof.

In the above, the alkyl group is preferably a lower alkyl group having 1 to 4 carbon atoms, and the alkanol is preferably a lower alkanol having 2 to 4 carbon atoms.

Also, ff! A heptamer having a group that can be introduced with a cationic group or converted into a cationic group after forming a combination can also be used.

(C)/Nionic ones include hydroxyethyl ester, hydroxypropyl ester, polyethylene glycol nistyl of the unsaturated carboxylic acids mentioned in (a),
These include alkoxypolyethylene oxide ester, glyceryl ester, and carboxamide.

These hydrophilic polymers are used in an amount necessary to substantially dissolve or ultrafinely disperse the polyboe dispersant formed in the aqueous medium, and the lipophilic moieties in the polymer dispersant Although it varies depending on the type and ratio of the woody part, Shichitsumar, which provides an ionic wood-loving group, has a large wood-loving property, so it can be used in a relatively small amount. Since the monomer that provides a nonionic wood-philic group has relatively low wood-philicity, it is desirable to use it in a relatively large amount.

The preferred specific content of the woodphilic moiety in the dispersant is (a) about 5 to 40% by weight in the case of an anionic woodphilic moiety, (b) about 5 to 40% by weight in the case of a cationic hydrophilic moiety. is about 10 to 50
% by weight, (c) approximately 20 to 60 in the case of nonionic woody parts.
% by weight is preferred.

Incidentally, it is preferable to include an unnecessarily large amount of wood-philic moieties in the dispersant, as this will reduce the water resistance of writing or recording using the pigment ink composition for ballpoint pens of the present invention. isn't it.

In addition, some pigments such as carbon black have a negative charge in an aqueous medium, and in addition to adsorption of the pigment by the lipophilic part of the dispersant, the dispersant is also absorbed by the electrical attraction force of the cationic part. For the purpose of firmly adhering to the pigment surface, it is preferable to use the cationic finishing agent (b) in addition to the wood-philic portion to form a polymer dispersant.

The polymer dispersant as described above used in the present invention is
It can be obtained by appropriately mixing the above monomers and using any conventionally known mixed polymerization method, such as solution polymerization, suspension polymerization, or emulsion polymerization. Known additives such as polymerization regulators may also be used if necessary. As long as the medium used at this time is wood or a wood-based solvent that can be used as an aqueous medium for ink, the obtained polymerization liquid can be used as it is as an ink medium,
Alternatively, the polymer can be used after being separated from the solution and then dissolved again.

The polymer dispersant obtained by polymerization in this way is not particularly defined by its molecular weight, but it has a molecular weight of 1,000
Those having a molecular weight in the range of 0 to 100,000 are important for properties such as the polymer content in the solution, the viscosity of the solution, and the viscosity of the pigment ink composition for ballpoint pens using the same, and the quality such as the fastness of recorded materials. It is preferable because

The amount of the dispersant used in the pigment ink composition for ballpoint pens of the present invention cannot be generally specified, since the properties of the pigment differ depending on the type of pigment and each brand. Approximately 3 parts by weight
300 parts by weight, preferably about 5 to 100 parts by weight. Inorganic pigments have a high density and each particle is relatively large, so the surface area is relatively small, so a relatively small amount of dispersant is required. Organic pigments have a relatively low density and fine particles are used. are used relatively often.

In particular, carbon black pigment has particularly fine particles, so it is particularly preferable to use it in a relatively large amount.

The unsaturated fatty acid salt added to the pigment ink composition for ballpoint pens of the present invention improves the writing feel, maintains a certain amount of ink discharge during continuous writing, and prevents wear of the pole seat. However, it is blended in order to provide stable writing properties over a long period of time.

Such unsaturated fatty acids preferably have 9 to 39 carbon atoms, and particularly preferred examples include salts of oleic acid, linoleic acid, linolenic acid, ricinoleic acid, or mixtures thereof.

In addition, the type of base that forms the salt may be wood-philic to the extent that the salt formed can be sufficiently miscible in the aqueous medium of the ink, and preferable examples include sodium, potassium, ammonium, mono-, di- or trialkanolamines, N-furkylalkanolamines,
These are water-soluble salts such as morpholine and N-ethylene glycol morpholine.

It is preferable to use the unsaturated fatty acid salt in an amount of about 0.01 to 5.0% by weight in the total amount of the pigment ink composition for ballpoint pens. The effect of the invention is poor, and the amount used exceeding the above range is not preferable because the effect of the invention does not improve in accordance with the amount used.

The aqueous medium constituting the pigment ink composition for ballpoint pens of the present invention may be an aqueous solution of a low-volatile or non-volatile wood-philic organic solvent, such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol. , dipropylene glycol, glycerin, diglycerin, methylcarpitol, ethylcarpitol, butylcarpitol, etc. are mixed and dissolved in a ratio of 5 to 200 parts per 100 parts of water.

Furthermore, conventionally known additives, humectants, rust preventives, preservatives, dispersants, lubricants, etc. may be added as necessary.

The pigment ink composition for ballpoint pens of the present invention consists of the above-mentioned components and formulations, and various methods can be used for its production. A typical method is mixing and grinding using a conventionally known dispersing machine such as a speed line mill or a roll mill.

In the above production method, the method for adding the unsaturated fatty acid salt is as follows:
Although it is possible to add it at the time of dispersing the application material, it is usually added after dispersion treatment and the addition of a non-volatile wood-loving organic solvent.
It is desirable to add it after diluting it with a non-volatile wood-philic organic solvent or a mixture thereof.

(Function/Effect) A ballpoint pen using the pigment ink composition for a ballpoint pen of the present invention has a specific additive added to the ink, and as a result, the ink ejects smoothly at the beginning of writing, and the drawn line does not fly during writing. Also, even in continuous writing, no phenomena such as fading or thinning of drawn lines due to a decrease in the amount of ink discharged were observed, and the stability over time is good. Therefore, various drawbacks of conventional pigment inks have been solved, and the pigment ink of the present invention has achieved recording with excellent writing properties and excellent light fastness, water resistance, etc.

Next, the present invention will be specifically explained with reference to reference examples and examples. In addition, parts and % in the text represent weight.

Reference Example 1 40% solution of water-soluble polymer dispersant (30 parts of methyl methacrylate, 20 parts of hydroxyethyl methacrylate,
20 parts of butyl acrylate, N.

A solution of a copolymer of 15 parts of N-dimethylaminoethyl methacrylate and 15 parts of methacrylic acid in 50 parts of isopropyl alcohol and 50 parts of butylcarpitol), 10 parts of carbon black pigment, and 25 parts of water.
0 parts and 2.0 parts of jetanolamine were added, dispersed in a ball mill for about 20 hours, and 27 parts of ethylene glycol and 22.9 parts of water were added so that the pigment concentration was 10%.
The mixture was further dispersed for 30 minutes to obtain a black pigment dispersion.

Next, this pigment dispersion was subjected to an ultracentrifuge to remove poorly dispersed coarse particles, and 1.0 part of a 10% ethylene glycol solution of benzotriazole was added as a rust preventive agent to create a black water-based ink with uniform particle size. A composition was obtained.

Reference Example 2 50% solution of water-soluble polymer dispersant (12.5 parts of ethyl acrylate, 15 parts of butyl methacrylate, 1 part of styrene)
35 parts of a copolymer of butyl cellosolve and 15 parts of methylcarpitol, consisting of 5 parts and 7.5 parts of methacrylic acid.
5 parts of solution), 10 parts of phthalocyanine pigment, 2 parts of water
Add 5.0 parts of potassium hydroxide and 0.3 parts of potassium hydroxide, disperse with a paint shaker for 20 hours, and add 2 parts of ethylene glycol.
81 and 23 parts of water were added, and the mixture was further dispersed for 30 hours.Then, the same procedure as in Reference Example 1 was carried out to obtain a blue water-based ink composition with uniform particle size.

Reference Example 3 Highly maleated portion of dehydrated castor oil fatty acid (manufactured by Ito Y Oil,
Hymalein 0F-20) and a condensation ester of bisphenol A with a propylene oxide adduct (see JP-A-60-26070) (6 parts of jetanolamine aqueous solution with a solid content of 50%) were added with jetanolamine 3
．． Add 3 parts of ethylene glycol, 2.0 parts of ethylene glycol, 3.0 parts of ethylenediaminetetraacetic acid disodium salt, 20.0 parts of water, and 1000 parts of carbon black pigment, and disperse in a ball mill for about 20 hours to reach a pigment concentration of 10%. 28.5 parts of ethylene glycol and 27.2 parts of water were added to the mixture, followed by further dispersion for 30 minutes, followed by the same treatment as in Reference Example 1 to obtain a black water-based ink composition with uniform particle size.

Reference Example 4 6 parts of methoxypolyethylene glycol adduct of styrene maleic anhydride copolymer (aqueous sodium hydroxide solution with solid content of 40%) and 36 parts of insoluble azo pigment paste (
9.0 parts of pigment) was dispersed in a ball mill for 6 hours, and further added with 10.2 parts of ethylene glycol, 6.3 parts of diethylene glycol, 28.0 parts of water, and 0.0 parts of benzotriazole.
5 parts were added, mixed and dispersed for an additional 15 minutes, and passed through a cartridge filter to remove coarse particles to obtain a red aqueous ink composition.

Example 1 3 parts of a 10% aqueous solution of triethanolamine oleate was added to 100 parts of the aqueous ink composition obtained in Reference Example 1 with stirring to prepare a pigment ink composition for a ballpoint pen of the present invention. Furthermore, this ink was filled into an internal ballpoint pen and the writing properties were tested. The results are shown in Table 1.

Example 2 A pigment ink composition for a ballpoint pen of the present invention was prepared in the same manner as in Example 1 by adding 2 parts of a lO% aqueous solution of linoleic acid jetanolamine salt to 100 parts of the aqueous ink composition obtained in Reference Example 1 with stirring. death.

A ballpoint pen test was conducted and the results are shown in Table 1.

Example 3 5 parts of a lO% aqueous solution of linolenic acid monoethanolamine salt was added to 100 parts of the aqueous ink composition obtained in Reference Example 1 to prepare a pigment ink composition for a ballpoint pen of the present invention similar to that in Example 1, and a ballpoint pen was prepared. The first test was carried out and the results were
Shown in the table.

Example 4 5 parts of a 10% aqueous solution of sodium lysylsinate was added to 100 parts of the aqueous ink composition obtained in Reference Example 2, and the following Example 1 was prepared.
A pigment ink composition for a ballpoint pen of the present invention was prepared in the same manner as above, and a test was conducted using a ballpoint pen. The results are shown in Table 1.

Example 5 5 parts of a 10% aqueous solution of ammonium salt of oleic acid was added to the aqueous ink composition obtained in Reference Example 3, and the results are shown in Table 1 in the same manner.

Example 6 6 parts of a 10% aqueous solution of morpholine salt of oleic acid was added to the aqueous ink composition obtained in Reference Example 4, and the results are shown in Table 1 in the same manner.

(Margin below) = 1 − rrr m rvv Reference example 1 Δ × @ @ @2
Δ X Q @ @3
XX Q @ ■4
Δ Δ 0 0 0 Example 1
@O@ @@ 2 @O@) @@ 3 o O@ @@4 @
0 @ @ @ 5 @ 00- @ @ @ 6 ■ OO- @ @ @ Tech... Initial calligraphy Write and check with your hand.

■! ...The writing quality after writing for 500m After writing with a 500m drawing tester, check by hand.

■・・・Storage stability After storage at 50°C for 3 months, take out and examine the writing quality.

■...Examine the degree of fading of the image using a light resistance fade meter for 200 hours.

■・・・Water resistance Immediately after writing, wet it with water and check for smudges. investigate.

Evaluation: O: Excellent O: Good Δ: Fair ×: Not good or better From the results in Table 1, the water-based pigment ink compositions for ballpoint pens of the present invention obtained in Examples 1 to 6 have good water resistance and light resistance, which are the characteristics of pigments. It was an extremely excellent pigment ink composition for ballpoint pens, as it satisfactorily satisfied the properties and provided writing taste and storage stability equivalent to those of conventional dye-type ink compositions.

Procedural amendment (own ship) May 30, 1986

Claims (6)

[Claims] (1) An aqueous pigment ink composition for a ballpoint pen, characterized in that the aqueous ink composition comprises a pigment, a dispersant, and an aqueous medium, and further contains a salt of an unsaturated fatty acid. (2) The aqueous pigment ink composition for a ballpoint pen according to claim (1), wherein the unsaturated fatty acid has a carbon number in the range of 9 to 39. (3) The aqueous pigment ink composition for a ballpoint pen according to claim (1), wherein the unsaturated fatty acid is oleic acid, linoleic acid, linolenic acid, ricinoleic acid, or a mixture thereof. (4) The aqueous pigment ink composition for a ballpoint pen according to claim (1), wherein the salt of unsaturated fatty acid is a water-soluble salt. (5) The aqueous pigment ink composition for a ballpoint pen according to claim (1), wherein the pigment is carbon black. (6) The aqueous pigment ink composition for a ballpoint pen according to claim (1), wherein the dispersant is a polymer dispersant.