JPS60173063A - Water-based pigment composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which has dull tint and excellent hiding powder, storage stability and resistance to light, water and chemicals, by coating a specified pigment powder mixture with a carboxyl group-contg. copolymer and dispersing it in an aq. alkaline soln. CONSTITUTION:A pigment powder mixture (A) having a particle size of 10mu or below, composed of 100pts.wt. titanium oxide pigment, 5-100pts.wt. aluminum silicate pigment and optionally not more than 100pts.wt. org. pigment such as azo lake is mixed with an aq. alkaline soln. (B) contg. a carboxyl group-contg. copolymer having an acid value of 30-500 [e.g. a methyl (meth)acrylate/maleic anhydride copolymer] in a quantity of 1/20 to double by weight that of component A. The resulting pigment dispersion is diluted with water and neutralized with an acid to precipitate a copolymer-coated composite pigment compsn. The compsn. is recovered by filtration, washed with water and pressed. The resulting press cake is dispersed in an aq. alkaline soln. to obtain the titled compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an aqueous pigment composition suitable for aqueous inks for writing instruments, poster colors, watercolor paints, aqueous printing inks, etc.
More specifically, it relates to an aqueous pigment composition that has good hiding power and good storage stability when used, has a matte color after use, and has excellent light fastness, water resistance, and chemical resistance. It is something.

In general, ink for writing instruments requires properties such as flowing smoothly from the writing instrument core material, not clogging, not easily drying in the core material, and not solidifying within the writing instrument due to changes over time. In addition, it must be harmless to humans, non-flammable, and have little odor.
Desirable properties include that characters formed by handwriting are light-resistant, water-resistant, chemical-resistant, and clear, can be coated over and over, and do not penetrate too much into the base material and do not set off. It is mentioned as.

However, the commonly used oil-based ink for writing instruments contains a flammable vehicle that is harmful to the human body and has a strong odor, and the characters formed by writing lack clarity and cannot be overpainted. There are other difficulties. On the other hand, although water-based inks for writing instruments solve the problems of oil-based inks mentioned above, they sometimes make characters formed by writing unclear, lack light fastness, water resistance, and chemical resistance. Alternatively, there is a problem that it becomes difficult to apply multiple coats. These problems can be solved to some extent by using pigments instead of dyes as coloring agents, but water-based inks containing pigments tend to aggregate when stored for long periods of time. Problems arise, such as clogging of the writing instrument core and sedimentation of the pigment in the container, making it impossible to obtain a predetermined color tone and sharpness of the written image.

Therefore, in order to solve such problems in water-based inks using pigments as colorants, various methods have been used, such as adding alkyl esters of acrylic acid or methacrylic acid to an aqueous medium containing a hydrophilic organic solvent. A method of dispersing pigments using a polymer whose main unit is
-35434), a method of adding short asbestos fibers to water-based ink (Japanese Patent Publication No. 52-40256)
, a method of centrifuging water-based ink to remove coarse particles that tend to settle (Japanese Unexamined Patent Publication No. 56-61466) has been proposed.

However, these methods do not necessarily fully satisfy each of the properties required of the above-mentioned writing instrument ink.

The present inventors have previously proposed an easily dispersible solid pigment composition that can be easily and homogeneously dispersed in an alkaline aqueous solution, alcohol, or an alkaline aqueous solution-alcohol mixture (
Furthermore, focusing on the extremely excellent storage stability of this pigment composition in an alkaline aqueous solution, they conducted extensive research in order to provide an aqueous pigment composition with a higher degree of dispersion stability. As a result of layering, a mixed pigment powder consisting of a titanium oxide pigment and an aluminum silicate pigment, and a mixed pigment powder consisting of an organic pigment further added thereto in some cases, was coated with a specific resin at a constant ratio of fluoride. Later, it was discovered that an aqueous pigment composition prepared by dispersing this pigment in an alkaline aqueous solution or an alkaline aqueous solution-alcohol mixture satisfies each of the properties required for the above-mentioned writing instrument ink, and based on this knowledge, the present invention was developed. I arrived at the eggplant.

That is, the present invention provides a mixed pigment powder of 00 parts by weight of a titanium oxide pigment and 5 to 100 parts by weight of an aluminum silicate pigment, or a mixed pigment powder to which an organic pigment in an amount of JooM+a' parts or less is added. 1/2 based on weight
The present invention provides an aqueous pigment composition which is coated with a carboxyl group-containing copolymer having an acid value of 30 to 500 in an amount of 0 to 2 times the total amount and dispersed in an alkaline aqueous solution.

The titanium oxide pigment used in the composition of the present invention is a typical white pigment, and has high hiding power, can be used in combination with an organic pigment to obtain a neutral color, and is chemically stable and non-toxic. On the other hand, aluminum silicate pigments exhibit protective colloid-like functions even at low viscosity in aqueous systems, and their viscosity changes little over time, giving them a matte finish. In addition, since these pigments are +-1 inorganic pigments, they are hydrophilic, easily wetted by water, and easily dispersed.

The aqueous pigment composition of the present invention is a mixed pigment consisting of titanium oxide and an aluminum silicate pigment having the above-mentioned properties, and in some cases, a mixed pigment further containing an organic pigment, which is mixed with a specific resin. After coating, this product is dispersed in an alkaline aqueous solution, and when used as an ink for writing instruments, it has good long-term storage stability at low viscosity, has a large hiding power for written images, and has a matte finish. Yes, and has excellent light resistance, water resistance, and chemical resistance.

It has characteristics such as:

The titanium oxide pigment used in the composition of the present invention may be either rutile type or anatase type, but rutile type is preferable from the viewpoint of high hiding power. -Also, aluminum silicate pigment is a mixture whose main components are silicon dioxide and aluminum oxide, and although the effects of the present invention can be expected to some extent even with silicon dioxide alone, the effect of the present invention is better when using a mixture of silicon dioxide and aluminum oxide. The invention has a great effect. The mixing ratio of these two components is appropriately selected depending on the purpose of use.

In addition, examples of organic pigments that may be used in combination with these include azo lakes, insoluble azo pigments, condensed azo pigments,
Azo pigments such as chelate azo pigments, phthalonanine pigments, perylene and perinone pigments, anthraquinone pigments,
Polycyclic pigments such as quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments, dye lakes such as basic dye lakes and acid dye lakes, nitro pigments, nitroso pigments, aniline black, and daylight pigments. Examples include photofluorescent pigments.

Preferred among these are azo pigments, polycyclic pigments, dye lakes, and daylight fluorescent pigments, and among the azo pigments are insoluble azo pigments and hyazo lakes, and among the polycyclic pigments are phthalocyanine pigments and quinacridones. Particular preference is given to pigments, dioxazine pigments and anthraquinone pigments. These pigments may be used alone or in combination of two or more.

Specific examples of these pigments are shown in the table below, but the pigments that can be used in the present invention are not limited to these examples.

/ /''/' The mixing ratio of each pigment in the mixed pigment used in the composition of the present invention is 9 per 100 parts by weight of the titanium oxide normal phase, 5 to 100 parts by weight of the aluminum silicate face, preferably 0 to 5.
0 parts by weight, if an organic pigment is used, its amount (・go 100 parts by weight)
Each is selected within a range of not more than 60 parts by weight, preferably not more than 60 parts by weight. If the amount of the aluminum silicate pigment is less than this, the storage stability will be lowered and a matte tone will not be obtained, and if it is more than this, the viscosity of the aqueous pigment composition will increase and its suitability will decrease. On the other hand, even if the amount of organic pigment is greater than the above, the color density does not change and the ink properties tend to be impaired. Further, in the case of a mixed pigment containing an organic pigment, in order to improve the stability after dispersion, it is preferable to add titanium oxide and aluminum silicate pigments during production of the organic pigment and co-precipitate to obtain a mixed pigment powder. The particle size of these pigment powders is preferably 10 μm or less.

The carboxyl group-containing copolymer used in the composition of the present invention has both the function of dispersing the mixed pigment and the function of fully adhering the pigment, and has a carbon-carbon double bond. It is obtained by copolymerization of an unsaturated compound monomer and an unsaturated carboxylic acid monomer. Examples of the unsaturated compound monomer having a carbon-carbon double bond include methyl acrylate, ethyl acrylate,
Unsaturated carboxylic acid esters such as butyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate, aromatic vinyl compounds such as styrene and vinyltoluene, chlorinated vinyl compounds such as vinyl chloride and vinylidene chloride, and nitriles such as acrylonitrile. Examples include vinyl compounds, organic acids such as vinyl acetate and vinyl propionate, and natural organic compounds such as rosin. Among these, acrylic esters, methacrylic esters, styrene and rosin are preferably used.

On the other hand, examples of unsaturated carboxylic acid monomers include monobasic lower unsaturated carboxylic acids such as acrylic acid and methacrylic acid, dibasic unsaturated carboxylic acids such as maleic acid, maleic anhydride, itaconic acid, and fumaric acid, and maleic acid. Examples include dibasic unsaturated carboxylic acid monoesters such as acid monoalkyl esters and fumaric acid monoalkyl esters. Particularly preferred among these are maleic anhydride and itaconic acid.

This copolymer of an unsaturated compound monomer and an unsaturated carboxylic acid monomer can be produced, for example, by mixing the above-mentioned monomer components in a predetermined ratio, and mixing the mixture in a conventional manner using a peroxide catalyst or an azo compound catalyst. It can be produced by copolymerization.

This copolymer may be either a random copolymer or a block copolymer, or may be a polymer or copolymer of an unsaturated compound monomer having a carbon-carbon double bond and an unsaturated carboxylic acid graft polymerized thereto. It can be anything.

Although the ratio of each monomer component in this carboxyl group-containing copolymer can be arbitrarily selected, it is necessary that the acid value of the produced copolymer be in the range of 30 to 500.

If this acid value is less than 30, the solubility of the copolymer in an aqueous solution is poor, while if it exceeds 500, it will have an adverse effect on the physical properties of the coating film such as water resistance, so the preferred acid value is 5.
It ranges from 0 to 200. Moreover, this copolymer may be used alone or in combination of two or more types.

The ratio of the mixed pigment powder to the carboxyl group-containing copolymer in the composition of the present invention is in the range of 20:1 to 1:2, preferably 101 to 1, on a weight basis, that is, the weight of the latter is 1/1 of the weight of the former. It is in the range of 2o to 2 times.

If the amount of the copolymer used is less than 1 to 0 times the amount of the mixed pigment powder, the function of dispersing the mixed pigment powder and the function of adhering the pigment to the base material when made into an ink will be poor; If it exceeds this amount, the function of adhering the pigment to the base material will not improve, and it will not become matte, which is impractical.

In order to coat the mixed pigment powder with the copolymer in the composition of the present invention, the copolymer is first dissolved in a totally alkaline aqueous solution. This alkaline aqueous solution may be an inorganic alkaline substance such as sodium hydroxide, potassium hydroxide, ammonia, or monoethanolamine, jetanolamine,
It is preferable to dissolve an organic alkaline substance such as an organic amine such as monoinoglobilamine or morpholine in water and adjust the pH to 8 to 10.

Next, the mixed pigment powder is added to the alkaline aqueous solution in which the copolymer is dissolved and mixed, and then kneaded and ground using a dispersion machine such as a sand mill, attritor, ball mill, three-roll mill, or colloid mill to disperse the pigment. Prepare the liquid. Next, this pigment dispersion is diluted with water and then neutralized by gradually adding an organic acid such as oxalic acid or acetic acid, or an inorganic acid such as hydrochloric acid or sulfuric acid while stirring, to form a composite pigment coated with the copolymer. Precipitate the composition. Next, this composite pigment composition is filtered, washed with water, and compressed to form a press cake. The press cake of the composite pigment composition thus obtained may be used as it is when dispersed in an alkaline aqueous solution, or it may be further dried and then pulverized with a pulverizer such as an atomizer. However, from the viewpoint of dispersibility, it is preferable to use the whole press cake as it is.

To prepare the aqueous pigment composition of the present invention, for example, the presscake or powder of the composite pigment composition described above is added to water, and then an inorganic alkaline substance or an organic alkali IJ fi substance as described above or the like is added to the water. Both are added and dispersed using a mixer or dispersion machine such as a dissilver, homomixer, or propeller stirrer, and the pH of the dispersion is adjusted.
Adjust so that it is between 7 and 10.

Further, in the preparation of the aqueous pigment composition, a surfactant may be used in combination, if necessary, in order to promote the stability of the composition. As this surfactant, an anionic surfactant, a nonionic surfactant, or both can be used. Further, in order to adjust the drying rate of the composition, it is preferable to use an alcohol. These alcohols include those that perform a quick-drying function and those that perform a slow-drying function. Examples of alcohols that perform a quick-drying function include methyl alcohol, ethyl alcohol, inflovir alcohol, and methyl alcohol. Examples include monohydric alcohols. On the other hand, polyhydric alcohols such as ethylene glycol, furopylene gelicol, diethylene glycol nat, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, etc. have a slow-drying function. Examples include alkyl ethers. These alcohols may be used alone or in combination of two or more.

The aqueous pigment composition of the present invention has a high hiding power and a matte appearance when used, has good long-term dispersion stability during storage, and has good physical properties such as light resistance, water resistance, and chemical resistance. In addition, it has characteristics such as less odor than oil-based products, and less penetration into the base material.
For example, it can be used as it is or as a semi-finished product in water-based inks for writing instruments, Bosk colors, water-based inks for water paints, etc.

Next, the present invention will be explained in more detail with reference to Examples. In addition, all parts and units in the examples are parts by weight and weight %.
Fully displayed.

Each characteristic was evaluated as follows.

(1) Concealability Evaluated in comparison with Mitsubishi felt-tip pen water-based W-500120 Lotus.

(2) Glossiness Measured using a crossmeter (1 to 100%, 6o0 specular glossmeter, ① Toyo Seiki Separation) [7].

(3) Storage stability The viscosity after being left in a constant temperature bath at 50° C. for 12 months was measured and evaluated using a B-type viscometer (■ manufactured by Tokyo Keiki).

(4) After actually writing on water-resistant imitation paper and leaving it for 2 minutes, it was immersed in water for 5 seconds and the bleeding of the drawn lines was examined.

(5) Light resistance Discoloration and fading was examined using a Ford O-meter for 100 hours.

Example 1 Titanium JR-803 (rutile type titanium oxide, Teikoku Kako ■
1) Loo part and Optiwhite P (s1o25], 0
~52.4%, At20542.1~44.3%, manufactured by Varghese), X-220 (water-soluble styrene)
Acrylic copolymer resin, acid value 175, manufactured by Seiko Kagaku Kogyo ■)
A copolymer resin solution prepared by dissolving 20 parts of 20 parts of 25% ammonia water, 4.7 parts of 25% ammonia water, 3.0 parts of isopropyl alcohol, and 62.3 parts of water was added, and after mixing, the mixture was kneaded with a sand mill.
A pigment dispersion was obtained by combining and grinding.

100 parts of this carotid dispersion (solid content 65 parts) was added to 900 parts of water, the temperature was raised to 90°C while stirring, and 3.5 parts of acetic acid was added to 900 parts of water.
1.5 parts were gradually added to precipitate the composite pigment composition. This composition was filtered, washed with water, and compressed to obtain 105 parts of press cake.

To 100 parts of the press cake (solid content: 61 parts) thus obtained, 2.8 parts of 25% ammonia water and 115 parts of ethyl alcohol were added so that the total amount was 175 parts. When water was added and dispersed with a sand mill, the pH was 9.2 and the viscosity was 21 cp.
A white aqueous pigment composition with a pigment content of 34.9% was obtained. The storage stability of this composition at low viscosity was investigated, and the composition was filled into an aqueous sign pen with a felt trap nib, and the opacity, gloss, water resistance, and light resistance were investigated by actual writing.

As a result, the storage stability, water resistance, and light resistance were all good, the hiding power was sufficient, and the color was matte with a gloss level of 2%.

Example 2 13.5 parts of acetate anilide was dissolved in an aqueous alkaline solution consisting of 2.9 parts of hydrogen hydroxide and 350 parts of water. (IVM) loo part, Oguchi White P15
part and 6.8 parts of sodium acetate, then 5 parts of acetic acid
, 2 parts were added gradually. 9.5% of 3,3'-dichlorobenzidine was added to the camping component thus prepared.
A solution obtained by tetrazotizing a portion of the solution by a known method was added over 120 minutes with stirring. After the coupling, 3
After stirring for 0 minutes, it was filtered and washed with water to obtain 288 parts of press cake containing C, I Pigment Yellow 12, titanium oxide, and aluminum silicate pigments (pigment content: 138.5 parts).
I got it.

To 250 parts of this press cake (120 parts of pigment),
85 parts of 350/H-482 (water-soluble acrylic copolymer resin, acid value 158.9, manufactured by Seiko Kagaku Kogyo ■) were mixed with 20 parts of 25% ammonia water, 20 parts of isopropyl alcohol, and 8 parts of water.
A copolymer resin solution dissolved in a solution consisting of 0 parts was added, mixed, and then kneaded and ground using a sand mill to obtain a pigment dispersion. This pigment dispersion was acidified, filtered, washed with water, and compressed in the same manner as in Example 1 to obtain 106 parts of press cake.

To 100 parts of the press cake thus obtained (solid content: 60.5 parts), 7.5 parts of 25% ammonia water, 15 parts of diethylene glycol, and Neugen FA-130T (nonionic surfactant, manufactured by Daiichi Kogyo ■) When 2 parts were added, water was further added to make a total of 177 parts, and the mixture was dispersed using a colloid mill, the pH was 9.5 and the viscosity was 21 cps.
A violet aqueous pigment composition having a pigment content of 20% was obtained. The properties of this composition were investigated in the same manner as in Example 1. As a result, the storage stability, water resistance, and light resistance were good, the hiding power was sufficient, and the composition had a matte tone with a gloss level of 4.
He was in charge.

Example 3 Titanium JR-500 (rutile type titanium oxide, Teikoku Kako ■
) 100 parts aluminum silicate #30 (5i0
25] -0 to 52.4%, Az2o342.1 to 44.
30 parts of X-209-8 (styrene-maleic acid copolymer resin, acid value 183) to 25 parts of Brilliant Scarlet FBT (C, I Pigment Red 22, manufactured by Mikuni Shiki ■) and X-22
A copolymer resin solution prepared by dissolving 055 parts of 25% ammonia water, 5 parts of inpropyl alcohol, and 70 parts of water was added, and after mixing, the mixture was kneaded and ground in a sand mill for 9 times to obtain a pigment dispersion. .

100 parts of this pigment dispersion (solid content 70.6 parts) was acidified, filtered, washed with water, and compressed in the same manner as in Example 1 to form a press cake.
Obtained 09 copies.

To 100 parts of the press cake (solid content: 65 parts) thus obtained, 6.5 parts of 25% ammonia water, 10 parts of n-propyl alcohol, 10 parts of ethylene glycol, and Emulgen A-90 (nonionic surfactant). , Kao Soap■
When I added 3 parts of (manufactured by) and added water to make a total of 210 parts and dispersed it with a sand mill, the pH was 9.1.
A red aqueous pigment composition with a viscosity of 26 cps and a pigment content of 20.0% was obtained.

The properties of this composition were examined in the same manner as in Example 1. As a result, the storage stability, water resistance, and light resistance were good, the hiding power was sufficient, and the composition had a matte finish with a gloss level of 3.
%Met.

Example 4 Titanium JR-401 (rutile type titanium oxide, Teikoku Kaji [
) 100 parts, OptiWhy) P2O part and Cyanine Blue 1MS Paste (C, I Pigment Blue 15
, manufactured by Mikuni Shiki ■) (2.5 parts of pigment), X-2
10-H-450 (water-soluble acrylic copolymer resin, acid value 1
80. (Manufactured by Seiko Kagaku Kogyo ■) 30 parts total 25% ammonia water 7.0 parts Improvil alcohol 2. F part and water 75
．． Copolymer resin solution whole eggs dissolved in a solution consisting of 3 parts,
After mixing, the mixture was mixed and ground using a sand mill to obtain a pigment dispersion.

100 parts of this pigment dispersion (solid content 62.2 parts) was acidified, filtered, washed with water, and compressed in the same manner as in Example 1 to form a press cake.
I got 07 copies.

00 parts of the press cake thus obtained (solid content 58.1 parts), 3.5 parts of 25% ammonia water, 20 parts of inpropyl alcohol, 5 parts of ethylene glycol, Nonipol 140 (nonionic surfactant, Manufactured by Sanyo Chemical Co., Ltd.)
2 parts and 1 part of Gear Ribbon L-400 (anionic surfactant, manufactured by Sanyo Kasei ■) were added, and then all the water was added so that the total amount was 155 parts, and the mixture was dispersed with a sand mill.
A light blue aqueous pigment composition with a pH of 9.1, a viscosity of 25 cps, and a pigment content of 30.1% was obtained. Regarding this composition,
As a result of examining each property in the same manner as in Example 1, it was found that the storage stability, water resistance, and light resistance were good, the hiding power was sufficient, and the film had a matte finish with a gloss level of 2%.

Example 5 Titanium JR-402 (rutile type titanium, manufactured by Teikoku Kako ■)
100 parts, 15 parts of Optiwhite P and 5 parts of First Violet RL (C Pigment Violet 23, manufactured by Sumitomo Chemical ■), 810 parts of X-209-810 and X-22.
035 parts total 25% ammonia water 13.5 parts and water 715 parts
After mixing, the copolymer resin bath C dissolved in the solution consisting of 50% was added, and after mixing, the mixture was ground in a sand mill to obtain a pigment dispersion. 100 parts of this pigment dispersion (solid content: 66 parts) was acidified, filtered, washed with water, and compressed in the same manner as in Example 1 to obtain 110 parts of a press cake.

5 parts of monoethanolamine, 20 parts of inpropyl alcohol, 5 parts of ethylene glycol, and 2 parts of Neugen EA-130T were added to 100 parts of the press cake (solid content: 60 parts) thus obtained, and the total amount was further increased to 200 parts. When water was added thereto and dispersed with Xanodomil, a purple aqueous pigment composition having a pH of 9.6, a viscosity of 27 CI)s, and a pigment content of 21.8% was obtained. The properties of this composition were examined in the same manner as in Example 1, and the results showed that it had good storage stability, water distribution, and light resistance, sufficient shell and ductility, and a matte finish with a gloss level of 3%. Met.

Claims (1)

[Scope of Claims] 1 A mixed pigment powder of ioo parts by weight of a titanium oxide pigment and 5 to 100 parts by weight of an aluminum silicate pigment is mixed with an acid value of 3° to 500 in an amount of 1/2 to 2 times the weight thereof. An aqueous pigment composition comprising a carboxyl group-containing copolymer coated with a carboxyl group-containing copolymer and dispersed in an alkaline aqueous solution. 2 Mixed pigment powder of 100 parts by weight of titanium oxide pigment, 5 to 100 parts by weight of aluminum silicate pigment, and 100 parts by weight or less of organic pigment is mixed with an acid value of 30 to 500 based on the weight of //20 to 2 times the amount. An aqueous pigment composition coated with a carboxyl group-containing copolymer and dispersed in an alkaline aqueous solution.