JPS5812911B2 - Suikeikakouganryyounoseizohouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing granular water-based processed pigments for use in water-based paints, paper coatings, textile dyeing, and the like.

Conventionally, as water-based processed pigments, paste-like aqueous dispersions in which pigments are dispersed in water using surfactants, water-soluble resins, etc. have been used.

However, this aqueous dispersion has a drawback in that it has poor storage stability and is prone to pigment precipitation and aggregation.

For this reason, redispersibility is poor and, for example, when used in the production of water-based paints, the dispersion time for paint preparation is long and it is difficult to disperse to a sufficient degree, resulting in lack of gloss and color separation in the paint film. It was done.

Therefore, it is necessary to thoroughly stir the aqueous pigment dispersion to make it homogeneous before adding it, and there are also disadvantages in handling it, such as it takes time to weigh it because it is in a paste form, and there is a lot of loss because it sticks to the container. Ta.

The present invention relates to a method for producing a granular water-based processed pigment that solves these problems.

That is, the present invention involves kneading a mixture consisting of 5 to 70% by weight of a nonionic water-soluble polymer compound with a softening point of 40° C. or higher, 30 to 95% by weight of a pigment, and an appropriate amount of water to form a uniform pigment dispersion, This pigment dispersion is mixed in the form of fine droplets in a solvent that is compatible with water but does not dissolve the polymer compound, and the water is rapidly transferred into the solvent to form a porous polymer compound-coated pigment. The present invention relates to a method for producing a granular water-based processed pigment, which is characterized by forming particles and separating and drying the particles.

Since the processed pigment obtained by the method of the present invention is granular, there is no problem in storage stability and it is easy to handle.

Furthermore, since the pigment is coated with a nonionic water-soluble polymer compound and is porous, it has the advantage of being easily redispersed simply by adding water.

This greatly facilitates the production of water-based paints, for example.

The nonionic water-soluble polymer compound used in the present invention has a softening point of 40°C or higher, preferably 70°C or higher.

This is because in order to stably store the resulting granular processed pigment, a softening point of 40°C or higher is required, and if the softening point is lower than this, the processed pigment particles made of the coating of the polymer compound will stick together. This is because stable particles cannot be obtained.

Examples of the nonionic water-soluble polymer compounds used in the present invention include hydroxyalkylcelluloses such as hydroxyethylcellulose, hydroxypropylcellulose, and hydroxymethylcellulose, methylcellulose, polyethylene oxide, polyvinyl alcohol, starch, dextrin, casein, gelatin, and glue. Can be mentioned.

In addition, when the processed pigment of the present invention is used for applications that do not require water resistance such as paper coating, the polymer compound may be one commonly used as a nonionic surfactant, such as a higher alcohol ethylene oxide addition. ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher alkylamines, ethylene oxide adducts, fatty acid amide ethylene oxide adducts, ethylene oxide adducts of fats and oils, polyglobin Polyethylene glycol type nonionic surfactants such as birene glycol ethylene oxide adducts, fatty acid esters of glycerol, fatty acid esters of pentaerythritol, fatty acid esters of sorbitol and sorbitan, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, alkanolamines Among J, those having a softening point of 40° C. or higher can be used, such as polyhydric alcohol type nonionic surfactants such as fatty acid amides.

Further, as the pigments used in the present invention, organic and inorganic coloring pigments commonly used in paints can be used.

For example, Hansa Yellow, Permanent Yellow HR,
Organic pigments such as Toluidine Red, Lake Red C1 Quinacridone Red, Woneting Gret, Copper Phthalocyanine Boule, Copper Phthalocyanine Clean, Green Gold, and Dioxateine Violet, as well as titanium oxide, zinc sulfide, lead white, lithopone, and zinc white. , carpon rack, graphite, iron black, red iron, red lead, vermilion, molybdenum red, galvanized copper, antimony red, ferrocyan copper, amber, iron oxide powder, sienna, yellow lead, zinc chromate, synthetic orca, titanium yellow, Ann, timmon yellow, barium yellow, strontium yellow, chromium green, chromium oxide green, pyriazine, zinc green, cobalt green, emerald green, myganese green, dark blue, ultramarine blue, cobalt blue, cerulean blue, manganese blue, manganese purple, etc. Inorganic pigments and extender pigments such as barite, precipitated barium sulfate, chalk, precipitated calcium carbonate, chalk, clay, abrasive powder, talc, diatomaceous earth, silica white, alumina white, gypsum, cross white, bentonite, calcium silicate, etc. can be given.

Also, metal powder pigments such as zinc powder, aluminum powder, lead powder, stainless steel powder, copper or copper alloy powder, chromate-based pigments such as strontium chromate, barium chromate, calcium chromate, barium potassium chromate, and basic lead chromate. Lead-based rust preventive pigments such as basic lead silichromate, red lead, calcium leadate, lead zinc oxide powder, lead cyanamide, and basic lead sulfate can also be used.

The mixing ratio of the pigment and the nonionic water-soluble polymer compound is 30 to 95% in terms of pigment weight concentration (PWC, that is, the weight ratio of the pigment to the sum of the solid content of the polymer compound and the pigment).

That is, if the proportion of the pigment exceeds 95% PWC, it becomes difficult to knead and disperse the pigment in the polymer compound, and if the proportion of pigment is less than 30% PWC, it lacks practical value as a processed pigment.

The solvent used in the present invention is an organic solvent that is compatible with water but does not dissolve the polymer compound, such as methanol, ethanol, n-propanol, impropanol, n-butanol, isobutanol, Alcohols such as butanol, tert-butanol, n-amyl alcohol, tetrahydrofurfuryl alcohol, norifuryl alcohol, cyclohexanol, n-hexanol, acetone, methylacetone, methyl ethyl ketone,
Ketones such as acetonylacetone, diacetone alcohol, isophorone, cyclohexanone, methyl formate, glycol carbonate, propyl formate, n-butyl formate, isobutyl formate, methyl acetate, methoxybutyl acetate,
Ethyl propionate, methyl lactate, ethyl lactate, lactic acid (
n- or iso)butyl, esters such as ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol There are polyhydric alcohols such as monoethyl ether and their derivatives, acetonitrile, formamide, dimethylformamide, etc., and these are selected and used as appropriate non-solvents depending on the nonionic water-soluble polymer compound used. do.

The solvent preferably dissolves 10 parts by weight or more, especially 20 parts by weight or more of water per 100 parts by weight of the solvent at 20°C.

Those with low water solubility in the solvent are not preferred in practice because they require a large amount of solvent in carrying out the present invention.

In the present invention, the method for uniformly kneading and dispersing the pigment in the aqueous solution of the polymer compound is carried out using a known dispersing machine that is normally used for manufacturing lacquers.

For example, a three-roll mill, a steel mill, a ball mill, a sand mill, an attriter mill, a Sassmeyer mill, etc. can be used.

A surfactant can be added to the aqueous solution as necessary to improve the dispersibility of the pigment, but when the processed pigment obtained is used in the production of paint, the amount added must be adjusted so as not to reduce the properties of the paint film. It is desirable to do so.

In the present invention, the following method may be used to mix the pigment dispersion in the form of fine droplets into a solvent.

(1) A method of dropping the pigment dispersion while stirring a large amount of solvent at high speed, or pressurizing the pigment dispersion into the solvent near the stirrer, (2) Continuously adding the pigment dispersion and the solvent respectively. (3) After spraying the pigment dispersion into the air and atomizing it,
A method is used in which the solvent is allowed to fall into a stationary solvent, or it is caught and mixed into a solvent that flows down like a shower or a curtain.

Note that the above-mentioned line mixer generally refers to a process in which a dispersed phase liquid and a dispersion medium liquid are continuously introduced into the mixer at the same time, and the two are instantaneously mixed to suspend the dispersed phase liquid in the dispersion medium liquid and prepare the mixture. The suspension is drawn out continuously, and the suspension process can be carried out in a sealed container that is shielded from the outside air.

Conventionally known line mixers that can be used as such a line mixer include, for example, Chemical Engineer.
's Handbook (Fourth Editi)
on/byJohn. H. Perry: McGRAW-
There are jet mixers, injector mixers, orifice mixers, nozzle mixers, centrifugal pump mixers, agitated line mixers, and double mixing bezels, which are described on pages 21-12 to 21-13 of HiLL BOOK COMPANY).

In addition, as a commercially available product, for example, S
-1 mixer and Onlator B unit (Sakura Seisakusho Co., Ltd.), pipeline homo mixer (Tokushu Machine Industry ■)
, the line agitator (Shimazaki Seisakusho), which has a stirring part that vibrates at high speed, and the shot mixer (Shimazaki Seisakusho), which is a static mixer without a rotating part.

When the pigment dispersion is mixed into a solvent in the form of fine droplets by the method described above, the water in the droplets immediately migrates into the solvent, thus forming porous resin-coated pigment particles. .

In the present invention, the formed polymer compound-coated pigment particles are then separated from the solvent by conventional filtration or a centrifugal separator.

Examples of filters that can be used include cake filters, pressure filters, vacuum filters, and centrifugal filters.

Next, the separated polymer-coated pigment particles are appropriately dried at room temperature or by heating to obtain granular water-based processed face particles.

As explained above, the processed pigment thus obtained is porous, so it has excellent solubility in the solvent of the coating resin, and therefore has the characteristic that the pigment can be uniformly redispersed into fine particles in a short period of time. It is.

The degree of porosity (porosity) of the obtained processed facial pores depends on the degree of compatibility between water and the solvent, and the selection of mixing conditions when the pigment dispersion is mixed into the solvent in the form of fine droplets. It can be changed in various ways.

The porosity can be measured using a mercury intrusion porosimeter.

From the viewpoint of redispersibility of the processed pigment, the porosity is determined by the volume of pores with a diameter of 2μ or less being 0. It is preferable that it is 2 CC/gr or more.

Further, the particle size of the processed pigment is preferably 10 μm or more from the viewpoint of dust generation and fluidity.

The present invention will be explained below with reference to Examples.

In the examples, all parts and percentages are expressed by weight.

Further, the pore volume is the volume of pores with a diameter of 2 μ or less measured using a mercury intrusion porosimeter, and is expressed in cc/gr.

Example 1 1600 parts of a 5% aqueous solution of hydroxyethyl cellulose (softening point 140-150°C) and 40 parts of carbon black were kneaded in a side grinder to obtain a pigment dispersion with a particle size of 10 μm or less using a grind gauge.

0.400 parts of this dispersion. The injection nozzle with a diameter of 5 mm was introduced into 4000 parts of isopropanol at a pressure of 50 kg/cm2, and the mixture was immediately heated to a rotation speed of 25 with a high-speed mixer.
00R. P. The mixture was stirred with M to prepare porous polymer compound-coated pigment particles.

This was filtered and dried to have an average particle size of 50μ and a pore volume of 0.
A black processed pigment of 6 cc/gr was obtained.

The processed pigment did not change in quality during storage and was easily redispersed by simply adding water and stirring.

Example 2 Hydroxymethyl cellulose (softening point 100°C or higher) 5
% aqueous solution 400 parts, phthalocyanine blue 30 parts and nonionic surfactant [Product name Demol P Kao Atlas ■
A mixture consisting of 1 part of [Made in Japan] was kneaded and dispersed with an attritor,
A pigment dispersion with a particle size of 5 μm or less was obtained using a grind gauge.

300 parts of this dispersion was added to 5000 parts of ethylene glycol monoethyl ether at a rotational speed of 5000 R. P. M was added dropwise under high speed stirring to prepare pigment particles coated with a polymer compound.

This was filtered and dried to give an average particle size of 60μ and a pore volume of 0.
A powdered blue processed pigment of 34 cc/gr was obtained.

The processed pigment did not change in quality during storage, and was easily redispersed by adding water and stirring.

Example 3 Polyethylene oxide (softening point 70-75°C: 7%
A mixture of 400 parts of the aqueous solution and 160 parts of Bengara was kneaded in a pebble mill to obtain a pigment dispersion with a particle size of 15 μm or less using a grind gauge.

4000 parts of acetone was circulated in a curtain shape.1
150 parts of the dispersion was sprayed from a distance of 1.5 mm at an air pressure of 4 kg/cm 2 using an air spray gun with a diameter of 1.5 mm, and was trapped in acetone droplets.

The formed polymer compound-coated pigment particles are filtered and dried,
A rust-red spherical processed pigment with an average particle diameter of 60 μm and a pore volume of 0.8 cc/gr was obtained.

The processed pigment does not deteriorate during storage and is easily redispersed by simply adding water and stirring.

Example 4 A mixture consisting of 500 parts of a 3% aqueous solution of polyvinyl alcohol (softening point 100°C or higher), 30 parts of Hansa Yellow, and 20 parts of talc was kneaded using a side grinder, and a pigment dispersion with a particle size of 10 μm or less was obtained using a grind gauge. Ta.

400 parts of the dispersion was passed through a spray nozzle with a diameter of 0.5 to 50 parts.
It was injected into 5000 parts of n-butanol at a pressure of kg/cnt, and immediately heated at a rotational speed of 2500 R. in a high-speed mixer. P.
The mixture was stirred with M to prepare porous polymer compound-coated pigment particles.

This was filtered and dried to have an average particle size of 50μ and a pore volume of 0.
5cc/gr of yellow processed pigment was obtained.

The processed pigment does not change in quality during storage and is easily redispersed by simply adding water and stirring.

Example 5 3% methyl cellulose (softening point 150°C or higher) aqueous solution 4
A mixture of 0.00 parts and 60 parts of titanium white was kneaded using a side grinder to obtain a pigment dispersion having a particle size of 15 μm or less using a grind gauge.

300 parts of this dispersion was added to 5000 parts of isobutanol at a rotational speed of 5000 R. P. M was added dropwise under high speed stirring to prepare pigment particles coated with a polymer compound.

This was filtered and dried to give an average particle size of 60μ and a pore volume of 0.
A powdery white processed pigment of 8 CC/gr was obtained.

The processed pigment did not deteriorate during storage and was easily redispersed by simply adding water.

Example 6 2% hydroxypropylcellulose (softening point 150-1
500 parts of aqueous solution (70°C), Phthalocyanine Blue 10
The mixture consisting of 50% was kneaded using an attritor, and a pigment dispersion having a particle size of 15 μm or less was obtained using a grind gauge.

400 parts of this dispersion was added to 16,000 parts of ethylene glycol monoethyl ether at a rotational speed of 5,000 R. P. M
was added dropwise under high-speed stirring to prepare pigment particles coated with a polymer compound.

This was filtered and dried to have an average particle size of 50μ and a pore volume of 0.
A powdered blue processed pigment of 34 cc/gr was obtained.

The processed pigment did not deteriorate during storage and was easily redispersed by simply adding water.

Example 7 40 parts of quinacridone red and polyethylene glycol fatty acid ester type nonionic surfactant (trade name: Meiko Manol 3299, manufactured by Kao Atlas ■, softening point 55-58°C)
1,600 parts of a 5% aqueous solution was kneaded with a sand grinder to obtain a pigment dispersion with a particle size of 10 μm or less using a grind gauge.

300 parts of this dispersion was added to 0. The mixture was introduced into 4000 parts of methyl ethyl ketone through a 5 mm diameter injection nozzle at a pressure of 50 kg/cm2, and immediately heated to a high speed mixer at a rotational speed of 2.
500R. P. The mixture was stirred with M to prepare porous resin-coated pigment particles.

This was filtered and dried to have an average particle size of 50μ and a pore volume of 0.
A blue pigment of 6 cc/gr was obtained.

When 30 parts of the processed pigment was added to 70 parts of water and stirred with a stirrer, it was redispersed to a particle size of 10 μm or less within 10 minutes, and when this was coated on paper, a colored paper with hiding power was obtained.

Comparative Example 1 Carbon black 20 parts Nonionic surfactant (trade name DE 10 parts Mole P, manufactured by Kao Atlas ■) Ethylene glycol 10 parts Water
A mixture consisting of 60 parts was kneaded using a sand grinder to obtain an aqueous pigment dispersion having a particle size of 10 μm or less using a grind gauge.

Comparative Example 2 The pigment dispersion of Example 1 was heat-desolvated to a solid state, and this was ground in a hammer mill to obtain a processed pigment with an average particle diameter of 50 μm and a pore volume of 0.05 cc/gr.

Comparative Experiment 1 The processed pigments obtained in Examples 1 to 6 and Comparative Examples 1 and 2 were kept in a sealed container and the condition after storage at room temperature for 6 months was investigated. No alterations such as powder aggregation were observed in the prepared powdery processed pigment.

On the other hand, in the aqueous pigment dispersion prepared by the method of Comparative Example 1, the pigment was precipitated and separated.

This precipitated aqueous pigment dispersion and 20 parts of each powdered processed pigment after storage were added to 80 parts of water, which was continuously stirred with a stirrer and the change in particle size was measured with a grind gauge.

The results are shown in Table-1. As is clear from Table 1, redispersion of the pigment in the processed pigment of the present invention is completed within 10 minutes of stirring, whereas the precipitation of the aqueous pigment dispersion of Comparative Example 1 remains at the particle size at the time of preparation even after stirring for 100 minutes. Moreover, the processed pigment with few pores of Comparative Example 2 could not be completely redispersed even after stirring for 100 minutes.

Comparative Experiment 2 Each processed pigment after storage in Comparative Experiment 1 was added to a water-soluble alkyd resin white paint (trade name: Delicon W White, Dainippon Toyo Co., Ltd.) in the formulation shown in Table 2, and mixed using only a stirrer. Dispersion mixing was performed for 10 minutes to obtain coating composition i-viii.

Coating the above coating compositions i to iii on an acid-treated mild steel plate,
Film thickness 30-35 formed by baking and drying at 50℃ for 20 minutes
Characteristic tests were conducted using μ coated test plates.

The results are shown in Table-3.

As described above, the processed pigments obtained according to the examples of the present invention and the comparative examples show a remarkable difference in terms of storage stability and redispersibility, and the pigments obtained by the method of the present invention are superior in all respects. Moreover, the paint using the processed pigment obtained by the method of the present invention was also very excellent in its coating performance.

Claims (1)

[Claims] 1 Nonionic water-soluble polymer compound with a softening point of 40°C or higher 5
A mixture consisting of ~70% by weight, 30-95% by weight of pigment, and an appropriate amount of water is kneaded to form a uniform pigment dispersion, and the pigment dispersion is mixed with water but dissolves the polymer compound. A granular aqueous system characterized by forming porous polymer compound-coated pigment particles by mixing fine droplets in a non-containing solvent and allowing water to rapidly migrate into the solvent, which are then separated and dried. Processed pigment manufacturing method.