JP3298803B2 - Aqueous pigment dispersion for writing or recording - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aqueous pigment dispersion,
In particular, aqueous pigments used for printing, recording, drawing, stamping or displaying characters, figures or images on paper, film or sheet using a writing instrument, a recording device, etc. utilizing capillary and / or capillary action The present invention relates to a dispersion, a water-soluble resin used for preparing the aqueous pigment dispersion, a method for producing the same, and an apparatus using the aqueous pigment dispersion.

[0002]

2. Description of the Related Art Conventionally, an aqueous pigment dispersion using an acrylic resin having a carboxyl group as a solubilizing group as a resin for dispersing a pigment has been known to provide stability of the dispersion and water resistance and durability of an image after writing or recording. It has been used as an aqueous pigment ink for plastic fiber pens, felt pens, ink jet printers, etc. because of its excellent properties.

[0003] An image formed by the above-mentioned water-based pigment ink is superior to an image formed by the dye ink in terms of water fastness and light fastness, but it is difficult to write or record on an image with a clear color or density or a non-absorbing surface. Is less inferior to the dye ink image. This is because a writing instrument or a recording device using an aqueous pigment ink utilizes a capillary or capillary phenomenon, and therefore it is necessary that the viscosity of the ink is low. This is because the ink is prepared with a reduced amount of the dispersing resin.

A water-based pigment ink desirable for the above uses has a high concentration and a low viscosity, and has a high surface tension when a writing or recording object is a liquid absorbing surface. This is an ink which is stable in that the pigment dispersion in the aqueous pigment ink does not change over time, has a clear writing or recorded matter, and provides images excellent in water resistance, light resistance and other durability.

[0005] In order to make the color of an image clearer and the sedimentation stability of the pigment of the aqueous pigment ink (that the pigment does not sediment during storage), it is desirable that the pigment is fine particles. In order to disperse the pigment, it is necessary to use a pigment dispersing resin. The ratio of the pigment dispersing resin and the pigment used has an optimum value in terms of the dispersibility of the pigment, the dispersion stability, and the coloring property of the pigment, and this optimum value varies depending on the type of the pigment, but the particle size is small. The more the pigment is used, the larger the amount of the pigment dispersing resin used relative to the pigment.

[0006] Therefore, high concentration using fine pigment,
In order to obtain a low-viscosity aqueous pigment ink, the molecular weight of the pigment dispersing resin must be reduced. However, from the viewpoint of the stability over time of the dispersion of the pigment, it is desirable that the molecular weight of the pigment dispersing resin is high to some extent.

[0007] Carbon black has been conventionally used as a black pigment and has the advantage of being excellent in concentration and durability. However, since its particle size is extremely small, it is difficult to completely disperse the pigment in an aqueous medium. The molecular weight of the dispersing resin must also be low. However, conventionally known pigment dispersing resins have a problem that when the molecular weight is reduced, the dispersion stability of the pigment is reduced.

A condensate of sodium naphthalenesulfonate and formalin, which has been conventionally used as a pigment dispersant, has excellent pigment dispersibility and dispersion stability of a pigment dispersion, and has a high concentration of aqueous pigment dispersion. Although the production of the liquid is possible, there is a problem that the water resistance of the written or recorded image is poor, and the writing feel is poor because the feel of the dispersion is too hard. Writing implements are not merely a matter of writing, but it is important that they can be written with a writing feel that meets the mind of the writer, and writing taste is an important property for writing implements.

[0009]

SUMMARY OF THE INVENTION In recent years, with the advance of ink-jet printing and jet printing and on-demand printing, development of a high-pigment-concentration and low-viscosity water-based pigment ink which has solved the above-mentioned problems of the prior art. Is required. Accordingly, an object of the present invention is to provide an aqueous pigment dispersion having excellent quality, especially a high pigment concentration and low viscosity, excellent writing quality, clear color, and durability such as water resistance of written or recorded matter. It is an object of the present invention to provide an aqueous pigment dispersion for writing or recording excellent in stability over time of pigment dispersion, and a water-soluble resin useful for preparing the dispersion.

[0010]

The above object is achieved by the present invention described below. That is, the present invention provides an aqueous pigment dispersion comprising a pigment, an aqueous medium, and a dispersing resin, wherein the dispersing resin is an unsaturated polyester resin and an acidic sulfuric acid.
Or a salt thereof, or a resin having a hydroxyl group.
To maleic acid, then acid sulfite or its salt
Is obtained by adding a polyester bond chain having an ester bond as a main bond as a lipophilic portion in a molecule or a side chain.
Writing or recording for aqueous pigment dispersion characterized in that it is a water-soluble resin having the following general formula (I) or (II) represented by water-solubilizing group as a parent <br/> aqueous portion . (However, M ¹ in the formula is a hydrogen atom, an alkali metal,
Or a lower aliphatic quaternary ammonium group,
M ² is hydrogen atom, alkali metal, ammonium group, lower
An aliphatic quaternary ammonium group or a lower alkyl group;
You. The present inventors have conducted intensive studies to solve the above-mentioned problems of the conventional water-based pigment ink. As a result, by using a specific pigment dispersing resin having a sulfone group or a salt thereof as a solubilizing group, The inventors have found that the above objects can be achieved, and have reached the present invention.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in more detail with reference to preferred embodiments. The aqueous pigment dispersion of the present invention comprises a pigment, an aqueous medium, and a dispersing resin, and the dispersing resin used herein has a lipophilic portion and a hydrophilic portion in the molecule, and the lipophilic portion contains an ester. A polyester bonding chain to be a main bond, a hydrophilic portion is a water-soluble resin having a sulfone group or a salt group thereof, the resin is, for example,
As an example, it is obtained by reacting a diol with a polycarboxylic acid having at least one sulfone group or a salt thereof and 2 to 4 carboxyl groups in one molecule. At this time, the degree of water solubility of the obtained resin can be adjusted by copolymerizing a polycarboxylic acid having no sulfone group or salt group. When a polycarboxylic acid having no sulfone group or its salt group is used as all the polycarboxylic acids, the sulfone group or its salt group may be introduced into the polyester resin after the production of the polyester resin. it can. These resins are composed of a lipophilic portion and a hydrophilic portion, wherein the lipophilic portion is a polyester bond chain mainly composed of an ester bond, and the hydrophilic portion is a sulfone group or a sulfone group and a carboxyl group or a salt group thereof. Having. Hereinafter, each raw material component of the polyester resin is specifically shown.

Examples of the diol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol,
Tripropylene glycol, 1,4-butanediol,
Aliphatic diols such as 1,6-hexanediol and neopentyl glycol; aromatic diols such as dihydroxymethylbenzene; alicyclic diols such as cyclohexanedimethanol; bisphenol-dihydroxyethyl ether; bisphenol-dihydroxypropyl ether; And alkylene oxide adducts of bisphenols such as ethylene oxide and propylene oxide. Examples of bisphenols include bisphenol A, bisphenol F, bisphenol A
F, bisphenol S and the like. These diols are used alone or in combination of two or more.

Examples of the dicarboxylic acid having a sulfone group or a salt thereof include sulfoaromatic dicarboxylic acids such as 5-sodium sulfoisophthalic acid, 2-sodium sulfoterephthalic acid and 2-potassium sulfoterephthalic acid. . These are also used in one or more types.

Examples of the polycarboxylic acid having no sulfone group or a salt thereof include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, and sebacic acid, adipic acid, maleic acid and fumaric acid. Saturated and unsaturated aliphatic dicarboxylic acids, trimellitic acid, aromatic tricarboxylic acids such as Diels Alder adduct of abietic acid and maleic anhydride, pyromellitic acid, naphthalenetetracarboxylic acid, biphenyltetracarboxylic acid, benzophenonetetracarboxylic acid, etc. Aromatic tetracarboxylic acids and the like. These polycarboxylic acids are used alone or in combination of two or more.

The water-soluble resin used in the present invention comprises the above-mentioned diol and a polycarboxylic acid having at least one sulfone group or its salt group and 2 to 4 carboxyl groups in one molecule. Is obtained by the reaction of
The above diol, for example, maleic acid, maleic anhydride, unsaturated polycarboxylic acids such as fumaric acid, or lower alkyl esters thereof, the condensation of derivatives such as acid halides to synthesize an unsaturated polyester resin, It can also be produced by adding an acidic sodium sulfite or the like thereto and introducing a sulfosuccinate group (group represented by the following formula (I)) into the resin. In this case, another polycarboxylic acid or a polycarboxylic acid having a sulfone group or a salt thereof can be used together with the unsaturated polycarboxylic acid. (Where M ¹ is a hydrogen atom, an alkali metal such as lithium, sodium or potassium, an ammonium group or mono-trimethylamine, mono-triethylamine, mono-tripropylamine, mono-tributyltylamine,
It is a lower aliphatic quaternary ammonium group which is a quaternized compound such as mono-triethanolamine and mono-tripropanolamine. )

Furthermore, a water-soluble resin having a group represented by the following formula (II) is produced by reacting maleic anhydride with a resin having a hydroxyl group and then adding sodium acid sulfite to the resin having a hydroxyl group. You can also. (Where M ¹ in the formula is the same hydrogen atom, alkali metal, ammonium group or lower aliphatic quaternary ammonium group as described above, and M ² is the same hydrogen atom, alkali metal, ammonium group as described above, It is a lower aliphatic quaternary ammonium group or a lower alkyl group having 1 to 4 carbon atoms.) In this case, the resin having a hydroxyl group is not limited to the polyester resin described above. A) Acrylic resin copolymerized with acrylate or acetophenone-formalin resin can be used. In this way, a water-soluble resin having a sulfosuccinate group or a salt thereof as a water-solubilizing group in the main chain or side chain can be obtained. The water-soluble resin used in the present invention may contain a carboxyl group or a hydroxyl group as a hydrophilic portion in addition to a sulfone group or a salt thereof.

In synthesizing the water-soluble resin used in the present invention, a solvent can be used if necessary.
As the solvent, a water-soluble solvent, particularly a solvent which does not lower the surface tension of the obtained aqueous pigment dispersion when the aqueous pigment dispersion is prepared from the resin of the present invention, is preferred. For example,
Examples thereof include diethylene glycol monomethyl ether and diethylene glycol monoethyl ether. Although a water-insoluble solvent can be used, in this case, it is desirable to remove the water-insoluble solvent after synthesizing the resin.

The water-soluble resin used in the present invention obtained as described above has a sulfone group or a salt thereof, and the content of the sulfone group or the salt thereof is determined by writing or recording the resin. When used as a pigment dispersant for
There is no particular limitation as long as it can function as a dispersant for the pigment, but the preferred content of sulfone groups or salt groups thereof is in the range of 3 to 30% by weight of the resin. When the content of the sulfone group or the salt group is less than the above range, the dispersion stability of the pigment in the aqueous pigment dispersion is insufficient, and the writing taste is satisfactory when the dispersion is used for writing. Not preferred because it is not at the level. On the other hand, if it exceeds the above range, it is not preferable because the water resistance of an image written or recorded using the aqueous pigment dispersion is insufficient.

When the water-soluble resin used in the present invention is used as a pigment dispersing resin, the preferred molecular weight is 60.
It is in the range of 0 to 10,000. If it is less than 600, the dispersion stability of the pigment and the rub fastness of the written image are not sufficient, and
If it exceeds 000, it becomes difficult to increase the pigment concentration in the aqueous pigment dispersion, and in ink-jet printing and jet printing, the ink liquid is liable to be spun due to the high molecular weight of the pigment dispersion resin. It is not preferable because the flight of the droplet becomes unstable. A more preferred molecular weight is in the range of 1,000 to 6,000. The water-soluble resin used in the present invention is used after being neutralized with a neutralizing agent, if necessary. Examples of the neutralizing agent that can be used include alkali metal compounds such as sodium, potassium, and lithium, ammonia, and amines.

The aqueous pigment dispersion for writing or recording of the present invention is obtained by mixing the above-mentioned water-soluble resin for pigment dispersion, a pigment, water and, if necessary, a water-soluble organic solvent, and dispersing the pigment. It is preferable that the obtained aqueous pigment dispersion is further subjected to centrifugal separation or the like to remove coarse particles that may be present in the dispersion, if necessary.

As the pigment used in the present invention, all conventionally known pigments can be used. For example, as organic pigments, phthalocyanine-based, azo-based, condensed azo-based, anthraquinone-based, perinone-perylene-based, indigo-thioindigo-based, isoindolinone-based, quinophthalone-based, azomethine-based, azomethineazo-based, dioxazine-based, quinacridone-based And aniline black and triphenylmethane pigments. Examples of the inorganic pigment include pigments such as carbon black, titanium oxide, iron oxide, iron hydroxide, spinel fired pigment, and metal powder.

In the present invention, it is desirable to appropriately select and use the type of pigment, the particle diameter and the type of pigment treatment depending on the purpose of use of the aqueous pigment dispersion for writing or recording of the present invention. Except when the formed image requires hiding power, it is usually preferable to use an organic fine particle pigment. In particular, when transparency is desired for the image, an organic pigment having a particle diameter of 0.5 μm or less is used. It is desirable.

The aqueous pigment dispersion for writing or recording of the present invention may contain, together with the above components, an ionic or nonionic pigment dispersing resin other than the pigment dispersing resin used in the present invention, a dispersant, and a thickener. Additives such as an antioxidant, a drying inhibitor such as urea, a rust inhibitor such as benzotriazole, a lubricant, an ultraviolet absorber, a water-soluble solvent, a surfactant, an anti-settling agent, and a fungicide can be appropriately added.

When an additive such as a drying inhibitor is dissolved in a water-soluble organic solvent and used, it is desirable to use an organic solvent having a large surface tension. For example, ethylene glycol, diethylene glycol, triethylene glycol, Glycerin is a preferred solvent.

The water used in the present invention is preferably deionized water, but tap water can be used if the hardness is sufficiently low. When using underground water or industrial water, it is desirable to pay close attention to metal ions and to use an ion sequestering agent in some cases. The content of the pigment and the pigment dispersing resin in the aqueous pigment dispersion of the present invention varies depending on the purpose of use of the dispersion, but usually the pigment concentration is 0.5 to 50% by weight, Concentrations range from 1 to 25% by weight.

In producing the aqueous pigment dispersion of the present invention, all dispersers conventionally used for producing aqueous dispersions can be used. In particular, a ball mill is a preferable dispersing machine of a closed type, and it is desirable to use a ceramic ball mill with a rubber lining applied to the main body, but a stainless steel ball mill can also be used with sufficient care.
In addition, the continuous disperser using the media is a semi-closed type, and the use of glass beads can prevent rust and metal fragments from being mixed into the obtained pigment dispersion.
This disperser is also a disperser suitable for the present invention.

The aqueous pigment dispersion of the present invention is usually prepared as an aqueous dispersion having a viscosity of about 30 to 3,000 cps containing a pigment and a pigment dispersing resin as main components using the above dispersing machine. Or for use in a recording device, it is diluted to a desired viscosity suitable for each application of 10 cps or less. Additives are usually added at the time of dilution. Furthermore,
If necessary, coarse particles and the like can be classified and removed by a centrifugal separator or the like after dilution.

The aqueous pigment dispersion of the present invention as described above can be used for writing information on ballpoint pens, plastic fiber pens, felt pens, fountain pens, brush pens, stamps, ink, paints, etc., ink jet printers, copiers, facsimile machines, etc. It is useful as a coloring agent used in equipment and the like. The aqueous pigment dispersion of the present invention is also useful as a coloring agent for aqueous flexographic inks, aqueous gravure inks, aqueous paints, and the like. Further, the water-soluble resin used in the present invention is useful not only as a resin for dispersing the pigment but also as an aqueous coating agent, an aqueous adhesive and the like.

[0029]

Next, the present invention will be described more specifically with reference to Examples, Comparative Examples and Reference Examples. The parts and percentages in the text are based on weight. Reference Example 1 127 parts of 5-sodium sulfoisophthalic acid and 190 parts of bisphenol A-dihydroxypropyl ether were placed in a reaction vessel, and 150
The mixture was condensed under stirring at ~ 250 ° C for 6 hours. Next, 100 parts of diethylene glycol monoethyl ether was added to the reaction solution, cooled to 90 ° C., and then 600 parts of water was added. The mixture was cooled with stirring to obtain a resin solution of the present invention. The solid content of this solution was 30%, and the acid value due to the residual carboxyl group was 3.68, which was the number average molecular weight of 3,040.
Is equivalent to The amount of sulfone groups in this resin is 1
2.6%.

130 parts of the above resin solution, 260 parts of water and 130 parts of carbon black were charged into a mixing vessel and stirred and mixed. After sufficiently dispersing the pigment in this mixed liquid using a horizontal media disperser, 280 parts of water was added and the mixture was sufficiently stirred, and coarse particles were removed by an ultracentrifuge to have a viscosity of 3.8.
A cps aqueous pigment dispersion (aqueous pigment ink) was obtained. When this water-based pigment ink was packed in a water-based plastic fiber pen and written on a high-quality paper, the handwriting was good, clear handwriting without bleeding was obtained, and the density was sufficient. Put a plastic fiber pen filled with water-based pigment ink with the writing part
After leaving it for months, there was no difference in the density of the handwriting between the beginning and end of writing.

Reference Example 2 65.1 parts of 5-sodium sulfoisophthalic acid and bisphenol A-dihydroxyethyl ether 196.2
Part of the reaction vessel, while reducing the pressure to 50 mmHg.
The mixture was condensed under stirring at 50 to 250 ° C for 6 hours. Then
The reaction solution was cooled to 80 ° C., and methyl ethyl ketone (ME
K) Add 200 parts and 39.7 parts of pyromellitic anhydride,
The mixture was reacted under stirring at 90 ° C. for 6 hours (the acid value of the resulting resin was 72.85, which corresponds to a number average molecular weight of 4,750). The obtained reaction solution was cooled to 80 ° C.
After 3.7 parts and 14.6 parts of caustic soda were added and sufficiently stirred to neutralize, the temperature was raised to 90 ° C. to remove most of the MEK, and further azeotroped with water under reduced pressure to remove the MEK. Removed well. Water was added to the obtained resin solution to adjust the solid content to 30%. The amount of sulfone groups in this resin is 6.
5%.

120 parts of the above resin solution, 255 parts of water, 120 parts of carbon black, 5 parts of benzotriazole and 200 parts of ethylene glycol were placed in a mixing vessel and mixed with stirring. After sufficiently dispersing the pigment in the obtained mixture using a horizontal media dispersing machine, 300 parts of water was added and sufficiently stirred, and coarse particles were removed by an ultracentrifuge to obtain an aqueous pigment ink. Was. This water-based pigment ink was filled into a water-based ballpoint pen and written on high-quality paper.
The handwriting density was sufficient, and the handwriting was not oozed immediately after writing. Therefore, this water-based pigment ink can be said to be a water-based pigment ink suitable for storage recording. The aqueous pigment ink was stored at 50 ° C. for one month, but no change was observed.

Example 1 Acetophenone-formalin resin (Hilac 110
H, manufactured by Hitachi Chemical Co., Ltd.) 141.5 parts and maleic anhydride 7
6 parts were dissolved in 220 parts of MEK and heated to 80 ° C. To this solution, 79 parts of triethylamine was added dropwise over 2 hours, and the mixture was further stirred at 80 ° C. for 5 hours. An additional 500 parts of water was added and most of the MEK was removed by heating and azeotropic distillation. To this solution was added 82.5 parts of sodium acid sulfite at 80 ° C, and the mixture was reacted at 95 to 97 ° C with stirring for 6 hours. The solid content was adjusted to 30% by adding water to the reaction solution, and the viscosity was 2,2.
A resin solution of 50 cps was obtained. The amount of sulfone groups in this resin was 21.2% of the resin.

[0034] 180 parts of the above resin solution, 300 parts of water and 180 parts of cyanine blue were placed in a mixing vessel and mixed with stirring. After sufficiently dispersing the pigment in the obtained liquid mixture using a horizontal media disperser, 340 parts of water was added and the mixture was sufficiently stirred, and coarse particles were removed by an ultracentrifuge to obtain an aqueous pigment ink. Was. When writing was performed on high quality paper with a marking pen filled with the aqueous pigment ink, the density of the handwriting was sufficient, and the handwriting did not strike through. Also, the marking pen was capped and left for one month with the writing portion facing upward, and then used, but writing could be performed without any problem.

Example 2 169.6 parts of hydrogenated bisphenol A and 47 parts of maleic anhydride were placed in a reaction vessel and reacted at 120 ° C. for 4 hours with stirring.
The mixture was dehydrated and condensed at 140 ° C. for 8 hours under reduced pressure of 0 mmHg. Next, 92.1 parts of trimellitic anhydride was added and reacted at 120 ° C. under normal pressure for 6 hours with stirring. The acid value of the produced resin was 182.5. The reaction solution was cooled to 90 ° C., and a mixed solution of 592.4 parts of water and 57.6 parts of 28% aqueous ammonia was added.
A neutralization reaction was performed for 0 minutes. Then, sodium acid sulfite 4
9.9 parts were added, and the mixture was heated to 95 to 97 ° C and reacted for 8 hours with stirring. The solid content of the obtained resin solution was 35%, the viscosity was 13,800, and the number average molecular weight was 1,327. The amount of sulfone groups in this resin was 11.7% of the resin
Met.

After sufficiently dispersing 100 parts of the above resin solution, 250 parts of water and 100 parts of carbon black using a horizontal media disperser, 200 parts of glycerin and 35 parts of water
0 parts were added and sufficiently stirred, and coarse particles were removed with an ultracentrifuge to obtain an aqueous pigment ink. When this aqueous pigment ink was used to print on high quality paper under the control of a personal computer with a jet printer, a clear image without bleeding was obtained. No dirt around the image was observed. Further, the aqueous pigment ink was stored at 50 ° C. for one month, but no change was observed.

Example 3 197.8 of a condensate of 1 mol of sebacic acid and 2 mol of cyclohexanedimethanol, 57.5 parts of fumaric acid and 1.2 parts of paratoluenesulfonic acid were placed in a reaction vessel.
The mixture was dehydrated and condensed with stirring at 160 ° C. for 6 hours. The resulting resin had an acid value of 71.3. Cool the reaction to 90 ° C.
A mixed solution of 682.6 parts of water and 17.4 parts of 28% aqueous ammonia was added, and a neutralization reaction was performed at 60 ° C. with stirring for 30 minutes. Acidic sodium sulfite 6 was added to the resulting translucent resin solution.
0.4 parts was added, and the mixture was heated to 95 to 97 ° C and reacted for 8 hours with stirring. The solid content of the obtained resin solution was 30%, the viscosity was 1,620, and the number average molecular weight was 1,878.
The amount of sulfone groups in this resin was 15.5% of the resin.

After 150 parts of the above resin solution, 225 parts of water, 100 parts of diethylene glycol, 5 parts of benzotriazole and 180 parts of insoluble azo pigment were mixed, the pigment was sufficiently dispersed using a horizontal media disperser. To the obtained dispersion, 240 parts of water and 100 parts of ethylene glycol were added, and the mixture was sufficiently stirred, and coarse particles in the dispersion were removed with an ultracentrifuge to obtain an aqueous pigment ink. When writing on high quality paper using a ballpoint pen filled with this aqueous pigment ink,
The writing quality was good, the density was sufficient, and handwriting without bleeding was obtained. The obtained image was immersed in water immediately after writing, but no elution of the pigment was observed. Also, the aqueous pigment ink was heated at 50 ° C.
For one month, but no change was observed.

Example 4 630 parts of fumaric acid, 1470 parts of bisphenol A-dihydroxyethyl and 10.5 parts of p-toluenesulfonic acid were placed in a reaction vessel, and heated to 130 ° C. in a nitrogen stream, followed by 180 hours over 5 hours. Temperature, and stirred at 180 ° C. for 90 minutes to cause a condensation reaction to synthesize a polyester resin.
The synthesized resin is taken out of the reaction vessel. The resin 209
Parts, 620 parts of water and 20 parts of 28% ammonia water were placed in a reaction vessel and stirred at 65 ° C. for 90 minutes to obtain a translucent resin dispersion. To this resin dispersion, 62 parts of sodium acid sulfite is added, and the mixture is stirred at 95 ° C. for 6 hours to sulfonate the resin. When 4 parts of water and 1 part of aqueous ammonia were added to the reaction mixture, a transparent resin solution was obtained. The resin content of this resin solution is 30%, and the viscosity of the resin solution is 25 ° C.
Was 530 millipascal second (mPa · s).

Next, 150 parts of the above resin solution, 36 parts of ethylene glycol, 6 parts of tetramethylene sulfone, 1 part of pure water
58 parts and 0.2 parts of sodium hydroxide are mixed well, and black pigment (Colour Black S-170, manufactured by Degussa) 1
50 parts are mixed with stirring to prepare a mill base.
Next, the pigment is dispersed in the mill base for 2 hours using a 250 ml mini motor mill (EIGER ENGINEERING LTD) under the conditions of a glass bead diameter of 0.5 mm and a rotation speed of 3000 rpm. Further, 250 parts of pure water was added to the above mill base to obtain an aqueous pigment dispersion having a pigment content of 20%.

With respect to 100 parts of the aqueous pigment dispersion, 34.5 parts of ethylene glycol, 16.0 parts of glycerin,
The mixture was diluted with a mixture of 4.5 parts of tetramethylene sulfone and 111.5 parts of pure water. The resulting diluent was 8000
Centrifugation was performed under the conditions of rpm and 20 minutes to remove coarse particles mixed in the diluent. Thereafter, the diluent was filtered through a 5 μm membrane filter to give a viscosity of 3.14.
mPa · s, surface tension 44.9 mN / m, pH 6.6
8. An aqueous pigment ink having a pigment average particle diameter of 113 nm was obtained.

The aqueous pigment ink was mounted on an ink jet printer (trade name: IO-735X, manufactured by Sharp), and printing was performed on Xerox 4024 paper and Canon PB paper. Measure the density of printed matter with a Macbeth densitometer (TR
918), the value was 1.28 for Xerox 4024 paper, and 1.28 for PB paper.
35. In addition, this printed matter was visually observed to be uneven in print density,
When the sharpness of the edge of the printed image was evaluated, the uniformity of the density of the solid printed portion was high, and the edge was sharp without whiskers or bleeding.

Example 5 464 parts of fumaric acid, 1580 parts of bisphenol A-dihydroxyethyl, 296 parts of phthalic anhydride and 6.6 parts of paratoluenesulfonic acid were placed in a reaction vessel and condensed at 150 ° C. for 90 minutes in a nitrogen stream. After the reaction, a polyester resin is synthesized by a condensation reaction at 175 ° C. for 3 hours, and the synthesized resin is taken out of the reaction vessel. 220 parts of the resin, 59 water
Take 5 parts and 20 parts of 28% ammonia water in a reaction vessel,
Stir at 65 ° C. for 90 minutes. As a result, a viscous milky white resin dispersion was obtained. To this resin dispersion, 41.6 parts of sodium acid sulfite was added, and the mixture was stirred at 95 ° C. for 6 hours to sulfonate the resin, whereby a transparent resin solution was obtained. The resin content of this resin solution was 30%, and the viscosity was 5300 mPa · s at 25 ° C.

Next, 150 parts of the above resin solution, 40 parts of ethylene glycol, 160 parts of pure water and 1.
Mix well 5 parts and add black pigment (Raven 2500 Powde
r (U), Columbian Carbon Japan Ltd.) 150 parts were mixed with stirring to prepare a mill base. Next, the mill base is dispersed in the same manner as in Example 1. 250 parts of pure water was added to the mill base to obtain an aqueous pigment dispersion having a pigment content of 20%.

For 100 parts of this pigment dispersion, 51.0 parts of ethylene glycol, 33.0 parts of glycerin, 1.0 part of polyoxyethylene oleate, a surfactant (trade name: Surfynol 82, manufactured by Air Products) Made)
A mixture of 0.8 parts and 212.0 parts of pure water is added and diluted. The obtained diluent is centrifuged (8000 rpm,
After 20 minutes), the remaining coarse particles in the dispersion were removed, followed by filtration with a 5 μm membrane filter to obtain a black ink. The results of various physical property tests of the ink were all good as shown in Table 1 below.

Example 6 300 parts of the resin solution synthesized in Example 7, 105 parts of ethylene glycol, 30 parts of tetramethylene sulfone, 6 parts of pure water
Mix well 15 parts and 0.6 parts of sodium hydroxide.
350 parts of this mixed liquid and pigment 150 described in Table 1 below
Mix the parts with stirring to prepare the millbase. Next, each mill base is dispersed in the same manner as in Example 1. 250 parts of pure water was added to this mill base to obtain a pigment content of 2 parts.
A 0% pigment dispersion was obtained.

Next, 52.0 parts of ethylene glycol and glycerin 3 were added to 100 parts of each pigment dispersion.
A mixture of 3.0 parts, 11.0 parts of sulfolane, 4.0 parts of polyoxyethylene alkyl ether sulfate, 0.8 parts of a surfactant (Surfinol 82) and 200.0 parts of pure water is added for dilution. . The obtained diluted solution was subjected to a centrifugal separation treatment (8000 rpm, 20 minutes) to remove coarse particles in the diluted solution, followed by filtration with a 5 μm membrane filter to obtain yellow, cyan and magenta inks, respectively. The results of various physical property tests of each ink were good as shown in Table 1 below.

[0048]

[Table 1]

A: Black pigment: Raven 2500 Powder
er (U) B: yellow pigment: trade name Seika Fast Yellow A3 C: blue pigment: trade name cyanine blue KBM D: red pigment: trade name Chromofine Magenta 6887 The above ink was ink jet printer (trade name BJ-
410J, manufactured by Canon Inc.), and printing was performed on synthetic paper for inkjet (Nasca Check Paper, manufactured by Sakurai Co., Ltd.). The density of the obtained printed matter was measured with a Macbeth densitometer (TR918), and the suitability for printing was evaluated to see whether the printed matter had whiskers or bleeding.

Example 7 100 parts of the resin solution (resin content 30%) obtained in Example 6, 500 parts of water and copper phthalocyanine blue (trade name: ZCA9)
01, Dainichi Seika Kogyo Co., Ltd.) 400 parts with a ceramic ball mill
Dispersion treatment was performed for 0 hour to obtain a blue aqueous pigment dispersion.
In addition, 240 parts of the resin solution obtained in Example 6, 12 parts of hydroxyethylcellulose, 448 parts of water and 1300 parts of rutile titanium white were subjected to a dispersion treatment in a ceramic ball mill for 10 hours to obtain a white aqueous pigment dispersion. 250 parts of a water-dispersible alkyd resin (RESYDROLVWA5477, resin content 40%, Hoechst Industries Co., Ltd.), 150 parts of a white aqueous pigment dispersion, 12.5 parts of a blue aqueous pigment dispersion, and a melamine-based crosslinking agent (trade name Cymel 370) , Solids 88
%, Manufactured by Mitsui Cytec Co., Ltd.) and mixed and stirred to obtain an aqueous paint. 100 parts of the paint was diluted with 20 parts of water, applied to a tin plate by spraying, air-dried, and baked at 140 ° C. for 30 minutes. The resulting coated plate was shiny and clear blue and was immersed in boiling water for 30 minutes, but the coating film did not change.

Example 8 The resin solution (resin content 30%) obtained in Example 6 was applied
It was applied to a thickness of 0 μm. A plain weave fabric of polyester fibers was stuck on top of this. The resin solution did not penetrate into the top of the cloth. On this, process printing by screen printing was performed using a color paste for pigment printing by a known method. After printing, the film was dried, heated at 150 ° C. for 10 minutes, and easily peeled when water was applied. In the obtained printed matter, the edges of the printed portion were sharp.

Comparative Example 1 Bisphenol A-dihydroxyethyl ether 21
3.6 parts, 86.4 parts of pyromellitic anhydride and 150 parts of diethylene glycol dimethyl ether are placed in a reaction vessel and reacted at 150 ° C. for 6 hours with stirring.
After cooling to 0 ° C., a mixed solution of 502 parts of water and 28% aqueous ammonia was added, and a neutralization reaction was performed for 10 minutes with stirring. The solid content of the obtained resin solution was 30%, the viscosity was 2,400, the acid value of the resin before neutralization was 148, and the number average molecular weight was 2,270.

120 parts of the above resin solution, 300 parts of water, 120 parts of carbon black and diethylene glycol 20
After the pigment was sufficiently dispersed using a horizontal media disperser, 260 parts of water was added and the mixture was sufficiently stirred, and coarse particles in the dispersion were removed with an ultracentrifuge to obtain an aqueous pigment ink. Obtained. When this aqueous pigment ink was stored at 50 ° C.,
It thickened in two weeks and lost fluidity.

Reference Example 3 200 parts of styrene, 300 parts of ethyl methacrylate, 2
-150 parts of ethylhexyl methacrylate, 100 parts of diacetone acrylamide and 250 parts of methacrylic acid were polymerized at 130 ° C using 30 parts of azobisisobutyronitrile as a polymerization initiator and 700 parts of propylene glycol monoethyl ether as a polymerization solvent. After completion of the polymerization, the polymer solution is cooled to 80 ° C., a mixed solution of 180 parts of 25% aqueous ammonia and 300 parts of water is added, and a sufficient neutralization reaction is performed with stirring. A resin solution having a 40% viscosity of 3,600 cps was obtained.

70 parts of the above resin solution, 280 parts of water, 200 parts of diethylene glycol, 5 parts of benzotriazole,
After mixing 5 parts of diethanolamine and 100 parts of carbon black, the pigment is sufficiently dispersed using a horizontal media disperser, and 340 parts of water and 10 parts of diethylene glycol are mixed.
0 parts were added and the mixture was sufficiently stirred, and coarse particles in the dispersion were removed with an ultracentrifuge to obtain an aqueous pigment ink. The viscosity is 4.
It was 1 cps. When writing was performed on high quality paper using a ballpoint pen filled with the aqueous pigment ink, the density of the handwriting was insufficient and bleeding was observed.

Reference Example 4 36 parts of a condensate of sodium naphthalenesulfonate and formaldehyde, 329 parts of water, 200 parts of diethylene glycol
Parts, benzotriazole 5 parts and carbon black 12
After mixing with 0 parts, the pigment was sufficiently dispersed using a horizontal media disperser, and 310 parts of water was added and stirred sufficiently,
Coarse particles in the pigment dispersion were removed with an ultracentrifuge to obtain an aqueous pigment ink. When writing was performed on fine paper using a ballpoint pen filled with the aqueous pigment ink, the writing quality was somewhat poor, and elution of carbon black was observed when immersed in water immediately after writing.

[0057]

According to the present invention described above, an aqueous pigment dispersion of excellent quality, especially when it is filled into a writing implement with a high concentration and a high surface tension and used for writing or printing with an ink jet printer, etc. The present invention provides an aqueous pigment dispersion capable of clear writing or recording with no stain on the periphery of a handwriting or the like. The aqueous pigment dispersion of the present invention provides a handwriting or recorded image having excellent water resistance and durability, and even when writing by a writing instrument filled with the dispersion or recording by a recording device such as a printing machine is interrupted, It has excellent ink suitability that does not cause clogging at the tip of a writing instrument and a recording device. The water-soluble resin used in the present invention is useful not only as a resin for dispersing the above-mentioned pigment, but also as a material for an aqueous coating material or an aqueous adhesive.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-271600 (JP, A) JP-A-2-235972 (JP, A) JP-A-59-206470 (JP, A) JP-A-61- 83267 (JP, A) JP-A-8-283645 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 11/00-11/20

Claims (7)

(57) [Claims] 1. An aqueous pigment dispersion comprising a pigment, an aqueous medium and a dispersing resin, wherein the dispersing resin comprises an unsaturated resin.
Add acidic sulfurous acid or its salt to the ester resin
Alternatively, maleic acid is added to a resin having a hydroxyl group.
And then adding acidic sulfurous acid or a salt thereof.
A polyester bond chain having an ester bond as the main bond.
As a lipophilic moiety, the following general formula (I)
Or a water- soluble pigment dispersion for writing or recording, which is a water-soluble resin having a water-solubilizing group represented by (II) as a hydrophilic portion. (However, M ¹ in the formula is a hydrogen atom, an alkali metal,
Or a lower aliphatic quaternary ammonium group,
M ² is hydrogen atom, alkali metal, ammonium group, lower
An aliphatic quaternary ammonium group or a lower alkyl group;
You. ) 2. The dispersing resin having a molecular weight of 600 to 10,000.
00 a writing or recording aqueous pigment dispersion according to claim 1, 3. A pigment concentration of 0.5 to 50% by weight,
The aqueous pigment dispersion for writing or recording according to claim 1, wherein the concentration of the dispersing resin is 1 to 25% by weight. 4. The brush according to claim 1, wherein the content of the sulfone group or its salt group in the resin for dispersion is 3 to 30% by weight.
Serial or recording aqueous pigment dispersion. 5. A sulfone group, an alkali metal compound, writing or recording aqueous pigment dispersion according to claim 1 which is salt formation with ammonia or an amine. 6. The writing instrument according to claim 1, which is for a writing instrument.
Or an aqueous pigment dispersion for recording. 7. A printer, copier, facsimile or
The aqueous face for writing or recording according to claim 1 , which is for a printing press.
Dispersion.