JP2001011342A - Modified silica-coated pigment, its production and composition containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a modified silica-coated pigment which has improved characteristics, especially improved flowability, improved touch, improved use touch and the like, and is useful for cosmetics, coatings, by coating an organic pigment or an inorganic pigment except zinc oxide and so on with silica-based substances. SOLUTION: This modified silica-coated pigment is obtained by coating the surfaces of (A) the particles of a pigment selected from organic pigments and inorganic pigments except zinc oxide, titanium dioxide, cerium trioxide and zirconium dioxide with (B) silica-based substances in an amount of 5 to 100 wt.% based on the component A. The inner layer of the coating layer of the coating pigment comprises silica, and the outer layer is an alkyl-modified silica. The pigment particles are preferably obtained by dispersing the component A in an organic dispersing medium with a dispersing agent, subjecting a tetraalkoxysilane to a sol-gel reaction in the dispersion system, and further subjecting an alkylalkoxysilane to a sol-gel reaction in the dispersion system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of modification of pigment particles by surface coating and its application.

[0002]

2. Description of the Related Art Modification of pigment particles or the like by surface coating has been proposed in many cases, and the dispersion stability, optical characteristics, chemical characteristics, flow characteristics, etc. of the particles can be improved by various coating methods. For example, in order to prevent sedimentation or aggregation of the inorganic pigment in the enamel, a low-molecular substance containing a fluoroalkyl group is previously added to the inorganic pigment (JP-A-4-20821).
It has been proposed to cover the surface with 3) or polyethylene oxide (JP-A-5-132413). However, it is well known that stable dispersion is difficult because inorganic and organic pigments have a large specific gravity, and it is well known that stable dispersion of pigments is achieved by giving up pigments in inks and using dye dyeings of polymer microspheres as colorants. There is even a proposal to secure it (Japanese Patent Publication 6-13657). In cosmetics, in order to prevent the compounded fine ultraviolet absorber from aggregating and deteriorating the ultraviolet absorption and visible light transmittance, the fine ultraviolet absorber is preliminarily wrapped in resin as spherical resin powder. In addition, by doing so, it is possible to prevent skin irritation due to the ultraviolet absorber and chemical deterioration of other coexisting components, and to eliminate the rough feel of the ultraviolet absorber during makeup and to improve the feeling of use (Japanese Patent Laid-Open No. 8-53568). Are also shown. Despite the vast number of proposals for the use of pigments and surface treatment methods, including the above examples, there are no thorough improvement measures yet, such as dispersion stability of pigments, flowability, etc. There is a strong demand for improvement in the feeling of use, such as the tactile sensation during makeup.

[0003]

An object of the present invention is to improve the characteristics of pigment particles, especially the feeling of use, such as fluidity and feel.

[0004]

It is an object of the present invention to improve the properties of pigment particles by devising a surface coating. In particular, the present inventors have found that, by coating zinc oxide fine particles with silica, it is possible to prevent the medium from being denatured by the photocatalytic action of zinc oxide while maintaining the ultraviolet absorbing ability of zinc oxide. No. 9-370480. Further, by making the outermost layer of the silica coating an alkyl-modified silica, in addition to the above-described effects, it is found that the fluidity and the feel of the composition containing the pigment are improved.
No. 468. This kind of improvement method has already been proposed in the aforementioned application, except when targeting zinc oxide, titanium oxide, cerium oxide, and zirconium oxide,
We decided to try other inorganic and organic pigments. Hereinafter, the present invention will be described in detail.

The pigments of interest in the present invention are inorganic and organic pigments except zinc oxide, titanium oxide, cerium oxide and zirconium oxide. The pigment is usually a powder containing fine primary particles or secondary particles which are aggregates thereof, or coarse particles obtained by further aggregating them, and is insoluble and non-reactive in a liquid medium in contact with the pigment at the time of use. The pigment in the present invention is intended for a pigment having a particle size usually used as a colorant, regardless of the powder composition, and the color tone is not limited.

The pigments which can be used in the present invention are various iron oxides such as red iron oxide, rare earth oxides as fluorescent substances, metal oxides exemplified by graphite, alumina and the like, and zinc oxide, titanium oxide and cerium oxide. , And metal oxide pigments other than zirconium oxide, titanium black, titanium yellow, ultramarine, metal compound pigments exemplified by cobalt blue, etc., carbon black, also phthalocyanine, sulene,
Azo, quinacridone, dioxazine, anthraquinone, indigo, thioindigo, azomethine,
Organic pigments such as perylene-based, perinone-based, and isoindolinone-based pigments and laked dyes, and inorganic and organic flaky pearl pigments. More specifically, it is a compound described in a handbook of the technical field such as a pigment handbook or a cosmetics / pharmaceutical raw material handbook.

[0007] Problems encountered when using pigments include the uniform dispersion of the pigment and the stability of the dispersion without sedimentation or aggregation for a long period of time. A large amount of mechanical energy is required for milling and kneading the pigment for uniform dispersion, and a dispersant must be used in combination for uniform and stable dispersion. There is a problem that it becomes necessary. Pigments that have been previously surface-coated with silica make it easy to disperse uniformly and stably, and solve the problem of skin irritation and color transfer due to direct contact of the pigment, but they are hydrophilic in lipophilic media and lipophilic media. In a medium in which a hydrophilic medium coexists, a decrease in fluidity and a rough touch are remarkable unlike in a hydrophilic medium, which is not satisfactory. It is unsatisfactory because it has a rough touch and spreads poorly when blended into a solid foundation for cosmetics. As a result of studying to solve these problems, the present inventors have found that the problems can be solved by further coating the pigment surface-coated with silica with alkyl-modified silica, and arrived at the present invention.

[0008] From the above, one of the features of the present invention is:
The pigment particles are surface-coated with two layers, the inner layer being coated with silica and the outer layer being coated with alkyl-modified silica. Such a coating is formed, for example, by performing a sol-gel reaction of tetraalkoxysilane in a liquid medium in which pigment particles are dispersed to form a silica layer, and then performing a sol-gel reaction of an alkyl-modified alkoxysilane. This can be realized by forming an alkyl-modified silica layer. The coating amount is 20 parts by weight of the silica layer and the alkyl-modified silica layer.
The object of the present invention can be achieved when the ratio is from 80 to 20: 5 to 100% by weight of the original pigment particles. If the coating amount is small, the effect is less, and if the coating amount is too large, the effect is saturated and is meaningless. In order to surely achieve the object of the present invention in various uses, the coating amount is preferably in the range of 20% by weight to 60% by weight.
Since the silica layer and the alkyl-modified silica layer have different portions in their effects, the ratio may be selected within the above range according to the application. In the same manner, when the coating of the inner and outer layers is the reverse of the above, that is, the inner layer is an alkyl-modified silica coating,
A pigment whose outer layer is surface-coated with two layers of silica is also feasible, but this reverse-coated pigment is not preferred because of its poor fluidity and feel.

As one of the methods for producing the coated particles of the present invention, a sol-gel reaction can be applied. The sol-gel reaction can produce various products by devising the type of starting materials and the reaction method. The basic principles and application examples are described in "Sol-Gel Science" by Saio Sakuhana (198).
Published on July 5, 2008, published by Agne Shofusha). Solk of alkoxysilane applied in the present invention
In the gel reaction, in a liquid medium in which water is present, alkoxysilane is hydrolyzed to generate Si-OH groups, which are condensed to form Si-O-Si groups.
In the formation of the inner layer coating of the present invention, tetraalkoxysilane is used as a starting material, so that the reactant becomes a sol at an intermediate stage of the condensation reaction.
The fraction of Si groups increases to a solid gel or silica.
In the sol state, if powder particles coexist in the system, the surface properties and the progress rate of the sol-gel reaction are appropriate,
The sol is adsorbed on the surface of the powder particles, where gelation proceeds. If the sol does not adhere to the surface of the powder particles, the surface of the particles cannot be coated, and the surface coating is substantially impossible even if the gelation reaction is too fast to realize the process of adsorbing the gel. Fortunately, the surface of the pigment particles in the present invention is fortunately suitable for adsorbing sols and depositing gels. Therefore, if the dispersion state of the pigment particles and the speed of the sol-gel reaction can be appropriately selected, the object of the present invention can be achieved. When the number x of the alkyl group R 'is less than 2, the alkyl-modified alkoxysilane represented by the formula (1) follows the same process as described above to form an alkyl-modified silica.

The alkyl-modified alkoxysilane used as a starting material for coating the outer layer in the production method of the present invention is a compound represented by the following general formula.

[0011]

R ' _X Si (OR) _4-X : wherein R and R' are the same or different and are C1-3 alkyl.

In the compound of the above formula, x is 1,
This includes the case where compounds in which x is 2 are mixed and the average value of the whole is less than 2. It also includes the case where some or all of these are low polymers. When R or R 'is higher alkyl, it is unsuitable for the same reason as in the preceding paragraph. It should be noted that, although it is possible to implement the case where R ′ is any of various perfluoro groups, it is disadvantageous for economy and corresponds to excessive quality for the purpose of the present invention.

The tetraalkoxysilane used as a starting material for coating the inner layer in the production method of the present invention is a compound represented by the following general formula.

[0014]

Embedded image Si (OR) _{4 wherein} R is C 1-3 alkyl.

R in the above formula is methyl, ethyl, propyl or isopropyl. This can be carried out even when it is a higher alkyl, but is unsuitable due to low reactivity. The tetraalkoxysilane defined by the above formula may contain a low polymer, or all may be a low polymer. R may be any of C1 to C3 alkyl, but if it is strong, ethyl is preferred because it has a moderate reaction rate and is easy to control so that coating can be performed more uniformly, that is, tetraethoxysilane. However, there is no significant difference in C1-3 alkyl.

In the present invention, a sol-gel reaction is applied as a method for coating pigment particles, but a reaction medium is used as a reaction medium so that a tetraalkoxysilane or an alkyl-modified alkoxysilane as a starting material can be dissolved to form a uniform coating. Use a mixture of water and a water-soluble organic solvent. On the other hand, since the pigment particles are insoluble, they cannot be uniformly coated unless they are kept in a well-dispersed state, and even if they cover coarse particles in which a large number of pigment particles are agglomerated, they lack suitability as a powder. Before use, the pigment particles contain many agglomerated coarse particles. Therefore, it is necessary to grind and disperse the particles in a medium usable as a sol-gel reaction medium in the presence of a dispersant. As the pigment particles are coated and unavoidable binding by the sol-gel reaction occurs with the progress of the sol-gel reaction, the particles used for the reaction must be dispersed with a smaller particle size than when used as a colorant. Is preferred. The dispersing agent must have a dispersing ability that does not cause aggregation or sedimentation of the pigment particles themselves other than the inevitable bonding, at least until the end of the sol-gel reaction. In addition, the material must not excessively accelerate or suppress the sol-gel reaction. When the dispersant satisfies such performance, the coated particles can be the desired surface-coated pigment particles.

From the above viewpoints, a search was made for a dispersant effective for the present invention. As a result, an alkanolamine salt of an acrylic polymer obtained by copolymerizing acrylic acid and / or methacrylic acid, N-vinylpyrrolidone-N, N-dialkyl Aminoalkyl acrylate copolymer, N-vinylpyrrolidone-N, N-dialkylaminoalkyl acrylate copolymer dialkyl sulfate, N-vinylpyrrolidone vinyl acetate copolymer, polyvinyl butyral, methyl vinyl ether-dialkyl maleate copolymer It has been found that one or more polymer dispersants selected from the group consisting of are effective. Substances having strong acidity or alkalinity are not suitable because the sol-gel reaction is not excessively accelerated or completed, and polyvinyl alcohol or ethylcellulose cannot exert a dispersing power in the system of the present invention even at neutrality. No effective substance was found for compounds known as surfactants and likely to have dispersing power, for example, various derivatives of polyoxyethylene. The dispersant varies depending on the type of the pigment to be coated and the composition of the coating reaction medium which is the dispersion medium. Can be achieved. For inorganic pigments, the range is preferably 2.0% by weight or more and 20% by weight or less, and for organic pigments, the range is preferably 0.1% by weight or more and 100% by weight or less. In dispersing the pigment powder to be subjected to the coating reaction, a wet dispersion method known in the art can be applied.

As has been found in the course of the search for the dispersant described in the preceding paragraph, in the method of the present invention, a mixture of water and a water-soluble organic solvent is used as a reaction medium. The lower aliphatic monohydric alcohols are preferred solvents because they sufficiently exhibit the dispersing ability of the dispersant, and the coating particles have good particle size and tactile sensation. Although a water-soluble organic solvent such as tetrahydrofuran or an aliphatic ketone can be used, the dispersing power is weak and the properties of the coated particles are inferior to those of the alcohol. Thus, a feature of the method of the present invention is the combination of the use of a specific dispersant and a water-soluble organic solvent. The amount of water used is
The amount required to hydrolyze all the alkoxy groups of the alkoxysilanes used for the coating reaction is essential, and the appropriate dispersion state of the pigment particles is secured in combination with the water-soluble organic solvent in the presence of the dispersant, Use an amount such that a smooth reaction proceeds. Generally speaking, 1.5 times the theoretical amount required for hydrolysis
A range of double to 15 times weight is appropriate. The amount of the water-soluble organic solvent used is an amount that ensures an appropriate dispersion state of the pigment particles in combination with water in the presence of the dispersant, and allows a smooth reaction to proceed. Use in the range of 1.0 to 15 times the weight. However, the total amount of water and water-soluble organic solvent used is preferably in the range of 3 to 20 times the weight of the pigment powder. It is possible to select the water or a part of the water-soluble organic solvent to be used as the dispersion medium.

In the sol-gel reaction in the method of the present invention, a catalyst is used. Various acids and bases are known as reaction catalysts. However, with an acid catalyst such as hydrochloric acid or acetic acid, it is possible to coat the surface of the powder particles, but it is not suitable because a dense and uniform coating cannot be made, and the reaction rate of the raw material alkoxysilane is insufficient. In addition, in the sol-gel reaction of the alkyl-modified alkoxysilane of the outer layer coating, the effect of promoting the reaction is low, and there is a problem in the economics of the coating treatment. Even with basic catalysts, bases such as potassium hydroxide and ammonia have too high a catalytic activity, and many sols, which are intermediates of the sol-gel reaction, gel themselves before coating the pigment particles, resulting in formation. The product is unsuitable because it is a mixture of a coated powder having a smaller coating amount than expected and a gel of silica or modified silica. Aliphatic amines are not as pronounced as ammonia, but the sol itself gels and the conversion of the starting alkoxysilane to the surface coating is poor. Although an attempt was made to improve the conversion by lowering the concentration of these basic catalysts, a satisfactory improvement could not be achieved, and only a marked decrease in the reaction rate was observed. As a result of searching for a catalyst that can avoid such difficulties, it has been found that in the surface coating method of the present invention, alkanolamines represented by the following general formula are effective and appropriate catalysts.

[0020]

R _3-X N (R′OH) _X : wherein R is hydrogen or alkyl, R ′ is alkylene, and x is 1, 2, or 3.

In the method of the present invention, a mixed solution of water and a water-soluble organic solvent, particularly a lower aliphatic alcohol, is used as a reaction medium. Therefore, alkanolamine is dissolved uniformly in the reaction medium and has a moderate catalytic activity. Select and use. Mixing ratio of water and water-soluble organic solvent in the reaction medium and x in the above formula
However, when the alkyl or alkylene in the above formula has 4 or more carbon atoms, the solubility and the catalytic activity are lowered, which is not suitable. Therefore, R is preferably selected from hydrogen or alkyl having 1 to 3 carbons, and R 'is preferably selected from alkylenes having 1 to 3 carbons. The present invention can be carried out in the case where the value of x is 1, 2, 3, i.e., any of mono-, di-, and trialkanolamines. Can be formed. That is, the sol-gel reaction can be controlled and moderately promptly advanced, and the entire amount of the sol can be formed into a coating gel on the surface of the pigment particles. Further, these catalysts are effective for both inner layer coating and outer layer coating, and can be used commonly for both processes. These points were a great difference from the above-mentioned bases such as potassium hydroxide, ammonia or aliphatic amines.

As the alkanolamine which can be suitably used as a catalyst for the sol-gel reaction in the method of the present invention,
Monoethanolamine, diethanolamine, triethanolamine, dimethylmonoethanolamine, monomethyldiethanolamine, diethylmonoethanolamine, monoethyldiethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, dimethylmonopropanolamine, monoethyldipropanolamine, etc. Examples thereof include diethanolamine, monomethyldiethanolamine,
Monoethyldiethanolamine and the like are preferable because a coated powder having an excellent tactile sensation can be obtained. The amount of the catalyst to be used is in the range of 5% by weight or more and 30% by weight or less based on the total weight of the alkoxysilanes used from the viewpoints of easy control of the coating reaction, touch feeling of the formed coated powder and the like. Preferably, the range of 10% by weight or more and 25% by weight or less is particularly suitable.

In coating the inner layer of the pigment particles in the present invention, first, the pigment particles and a dispersant are added to a part of a mixture of water and a water-soluble organic solvent, and the pigment particles are adjusted to a suitable particle size by a known method. To prepare a dispersion of pigment particles. It is convenient that the liquid of the dispersion medium has the same composition ratio as the medium of the sol-gel reaction, but this is not always necessary and a composition ratio suitable for dispersion may be used. A dispersion of tetraalkoxysilane and pigment particles is added to a mixed solution of water and a water-soluble organic solvent in a reaction vessel with stirring, and mixed.
When the catalyst is added and stirring is continued, hydrolysis and condensation of the tetraalkoxysilane proceed, and the viscosity of the system increases with the formation of the sol. In the steps leading up to this, the reaction temperature is set to 10
It is preferable to set the room temperature to 30 ° C. This is to avoid the formation of a gel not involved in the coating. The dispersion of pigment particles may be added at the stage of sol formation, not at the beginning. Subsequently, when the temperature is raised to accelerate the gelation reaction and the reflux heating at 60 to 90 ° C. is continued, the gelation reaction proceeds while the reaction intermediate is deposited on the surface of the pigment particles, and the viscosity of the system decreases. Thus, when the alkyl-modified alkoxysilane is added to the reaction system in which the inner layer coating has been completed, hydrolysis and condensation of the alkyl-modified alkoxysilane occur, and a gelation reaction is caused while depositing on the surface of the coating inner layer of the pigment particles through gel formation. The process proceeds to complete the outer layer coating reaction. In the first half of the outer layer coating reaction, unlike the first half of the inner layer coating performed at room temperature, a temperature higher than room temperature is possible. The reaction product was separated by filtration, and the remaining catalyst and dispersant were washed with a mixed solution of water and a water-soluble organic solvent or a single substance thereof to obtain a solution.
Heat drying at about 160 ° C. is performed and then lightly pulverized using a device such as a pin mill or an atomizer to obtain a coated powder intended for the present invention. The reaction yield of the alkoxysilanes on the coated powder is almost consistent with the calculated value that they were converted to silica or modified silica. Probably due to the presence of unreacted ends -OH or -OR groups and traces of residual dispersant, in most cases the yield is 0-4% of the calculated value.
Excess amount. It is conceivable that these are reduced by firing at a high temperature, but at such a temperature, deterioration of the modified silica in the outer layer is inevitable, so firing is not necessary.

The characteristics of the coated particles of the present invention are that when the two-layer coated pigment particles of the present invention are dispersed in a medium, uniform dispersion can be achieved more easily than in the case of simple single-layer coating. When the medium is in a liquid state and is in a liquid state even after dispersion, uniform dispersion is stably maintained for a longer period of time, excellent in fluidity, and cosmetics spread well in liquid or powdery cosmetics, rough by coated particles. Good touch feeling and feeling of use such as no feeling are obtained, pigment concentration in cosmetics can be increased, pigments on clothes and skin can be easily removed, etc. .

The coated pigment powder of the present invention is easily dispersed in a fluid medium, and has excellent fluidity when the composition is in a liquid state. In addition to the application of various types of resin molded products exemplified by polyethylene resin, polypropylene resin, polystyrene resin, acrylic resin, polycarbonate resin, urethane resin, alkyd resin, epoxy resin, melamine resin and their copolymer resins It can be applied to paints and adhesives that use these resins or low-polymerized products, and is also applicable when they contain additives such as dyes, pigments other than the present invention, ultraviolet absorbers, and plasticizers. It is possible.

Hereinafter, the present invention will be described in more detail with reference to examples. All parts in Examples and Comparative Examples are parts by weight. The particle size of the coated powder was measured with a laser diffraction particle size distribution analyzer after dispersing the powder in liquid paraffin. Evaluation of dispersion stability is performed by dispersing the powder in a hydrophobic liquid, sealing the container in a transparent container, standing at room temperature, and visually determining whether sedimentation of the powder occurs with time. After standing for 1 day in a 50 ° C constant temperature oven,
An accelerated dispersion stability test was conducted to visually determine the presence or absence of sedimentation by continuing the repetitive cycle of standing still.

[0027]

Example 1 Agglomerated powder of ferrous oxide (Bengara) 24
0.0 part was 40 parts of isopropanolamine salt of acrylic acid-modified acrylic resin (75% neutralization degree) as a dispersant.
It was charged into a bead mill together with 96.0 parts of a 0% ethanol solution and 464.0 parts of an equal weight mixture of isopropanol and water as a medium, and dispersed while pulverizing. In a reactor having a liquid dropping device, a reflux condenser, a stirrer, and an external heating device, 177 parts of tetraethoxysilane and 140 parts of isopropanol were charged, and 400 parts of the dispersion of Bengala was stirred at room temperature for 10 minutes. The mixture was dropped and stirred for a while to obtain a uniform dispersion. Then, a catalyst solution consisting of 36 parts of diethanolamine and 200 parts of water was added dropwise over 30 minutes while stirring at room temperature, and while stirring was continued for 40 minutes, the viscosity of the system increased and sol formation of silane proceeded. The reaction temperature was increased and maintained at 80 ° C. by external heating. During 30 minutes, the sol was gelled while adsorbing on the red iron oxide particles, and the viscosity of the system decreased. A reaction reagent consisting of 33.0 parts of monomethyltrimethoxysilane and 20 parts of isopropanol was added,
When stirring was continued at 80 ° C. for 60 minutes, the reaction was terminated because the viscosity of the system increased halfway and then decreased again. After cooling, the reaction product was filtered and washed with water to remove the solvent, dispersant and catalyst. After drying at 120 ° C., the yield of the coated powder was 188.0.
Department. This is substantially equivalent to a weight of 186.3 parts assuming that the total amount of silanes has been converted to silica and methyl-modified silica to coat the redwood. Therefore, the composition of the coating powder is calculated to be 64.5% by weight of red iron oxide, 27.0% by weight of silica, 8.5% by weight of methyl-modified silica, and the ratio of the coating layer is 35.5% by weight. The obtained coated powder was pulverized for 20 seconds using an impact pulverizer. The particle size of the coated powder after pulverization was distributed between 0.05 and 3 μm, and the average particle size was 0.5 μm.

[0028]

Comparative Example 1 A sol-gel reaction was carried out in the same manner as in Example 1, except that the outer layer was not coated with monomethyltrimethoxysilane, but tetraethoxysilane was increased only in the inner layer coating reaction. The coating is quantitative, 65.0% by weight of Bengala,
Silica-coated red iron oxide of 35.0% by weight was obtained. The particle size and particle size distribution after pulverization were the same as in Example 1.

[0029]

Comparative Example 2 A sol-gel reaction was carried out in the same manner as in Example 1, except that the inner layer was not coated with tetraethoxysilane, but monomethyltrimethoxysilane was increased under the reaction conditions for the inner layer. The coating was quantitative, giving a methyl-modified silica-coated veneer of 66.0% by weight of bengara and 34.0% by weight of methyl-modified silica. The particle size and particle size distribution after pulverization were the same as in Example 1.

[0030]

Example 2 When the crushed coated red bengal powder obtained in Example 1 was sprayed on a water surface, the powder was floated without settling. One week later, it remained floating.

[0031]

Comparative Example 3 For comparison with Example 2, the same experiment as in Example 2 was performed on the ground silica-only coated red iron oxide powder obtained in Comparative Example 1, and the powder sedimented.
The pulverized methylated silica-modified single bengal powder obtained in Comparative Example 2 floated without settling. The original uncoated bengal powder settled out.

[0032]

Example 3 Three parts of the pulverized coated red bengal powder obtained in Example 1 was kneaded with 10 parts each of castor oil, liquid paraffin, and squalane to form a paste. All the pastes were excellent in fluidity, and when the stick immersed in the paste was picked up on the paste, the paste flowed down naturally like a continuous string. The powder was found to be familiar with these hydrophobic substances.

[0033]

Comparative Example 4 For comparison with Example 3, the same experiment as in Example 3 was carried out using the ground bengal powder alone coated with the crushed methyl-modified silica obtained in Comparative Example 2, which was equivalent to Example 3. However, in the case of the crushed coated Bengala powder obtained in Comparative Example 1 and the uncoated original Bengala powder, the continuous thread was not drawn in any case.
It ruptured in a lump and fell with a feeling of dents and did not have fluidity.

[0034]

Example 4 Three parts of the ground coated bengara powder obtained in Example 1 were mixed with 100 parts each of castor oil and liquid paraffin.
Each part was separately dispersed using a homomixer, and both were subjected to a three-month normal temperature dispersion stability test and an eight-cycle accelerated dispersion stability test. In each case, a good dispersion state was maintained, and no sedimentation or aggregation of the powder was observed.

[0035]

Comparative Example 5 For the purpose of comparison with Example 4, the same experiment as in Example 4 was carried out using the ground pulverized methylated silica powder obtained in Comparative Example 2 alone. 4 showed the same behavior as that of Comparative Example 1, but in the case of the pulverized coated red bengal powder obtained in Comparative Example 1, it took about one month in the room temperature dispersion stability test and at the end of 4 cycles in the accelerated dispersion stability test. A portion settled out and a thin layer of transparent supernatant was observed. In each case, the uncoated original red iron oxide powder ensured coagulation and sedimentation of the powder on the second day in the room temperature dispersion stability test and at the end of one cycle in the accelerated dispersion stability test, and further worsened thereafter.

[0036]

Example 5 Using the coated powder of the present invention, an O / W emulsion type foundation was prepared with the following composition. That is, the composition was as follows: 0.7 parts of the crushed coated Bengala powder obtained in Example 1 and 3.0 parts of talc, 0.5 part of bentonite as an aqueous phase, and 0.1 part of polyoxyethylene sorbitan monostearate in Example 1. 7 parts, triethanolamine 1.0
Parts, propylene glycol 10.0 parts, purified water 56.4
3.0 parts of stearic acid as an oil phase, 7.0 parts of isohexadecyl alcohol, 2.0 parts of glycerin monostearate, 2.0 parts of liquid lanolin, and 8 parts of liquid paraffin.
0 parts, 0.05 parts of preservative and 0.05 parts of fragrance were used. The preparation procedure was as follows: first, bentonite was dispersed in propylene glycol, and the purified water and then the remaining aqueous components were sequentially added, and the aqueous phase was uniformly mixed with a homomixer at 70 ° C., and the powder components previously mixed were stirred. It was added and dispersed below. At this time, the coated red iron powder was easily and quickly dispersed. Further, the oil phase was added while hot and emulsified and dispersed. After cooling, a fragrance was added. The obtained foundation had good lubricity and tactile sensation during makeup, and showed a good finish with transparency. When subjected to an accelerated dispersion stability test, no phase separation or sedimentation or aggregation of the coated Bengala powder was observed after 45 cycles.

[0037]

Comparative Example 6 For comparison with Example 5, the same experiment as in Example 5 was performed using the ground silica-only coated red iron oxide powder obtained in Comparative Example 1. Compared to the case of Example 5, when the powder component was added and dispersed, the stirring time in the homomixer to reach the uniform dispersion required an extra 60%, and the obtained cosmetic felt rough in the makeup. However, it was unsatisfactory in terms of growth, requiring further improvement. In the accelerated dispersion stability test, no sedimentation or aggregation of the coated oxide was found after 45 cycles.

[0038]

Example 6 45.0 parts of crushed coated bengala powder obtained in Example 1, 44.9 parts of talc, starch 2.0
Parts, 3.0 parts of magnesium stearate, 3.0 parts of liquid paraffin, 2.0 parts of isopropyl myristate, 0.05 parts of preservative, and 0.05 parts of fragrance are uniformly mixed, and after pulverization, coarse particles are removed by a sieve. Then, it was compression molded on a middle plate. The obtained powder foundation had good lubricity and tactile sensation during makeup, and showed a good finish with transparency.

[0039]

Comparative Example 7 For comparison with Example 6, the same experiment as in Example 6 was conducted using the ground silica single-coated powder obtained in Comparative Example 1. The obtained cosmetic has a rough feel during makeup and has a spreadability in Example 6.
Was inferior to the case.

[0040]

Example 7 100 parts of polystyrene resin pellets and 2 parts of the pulverized coated bengala powder obtained in Example 1 were mixed and extruded into a strand by a melt extruder. When the strand was cut into thin pieces and observed, the powder was uniformly dispersed in the strand.

[0041]

Comparative Example 8 For the purpose of comparison with Example 7, the same experiment as in Example 7 was performed using the ground silica-only coated red iron oxide powder obtained in Comparative Example 1, and the powder was placed in the strand. Although dispersed almost uniformly, pigment powder particles exceeding 10 μm were observed in some places. Also,
When the original non-coated Bengala was used, 1
There were many pigment powder particles exceeding 0 μm, and the strand had a varying degree of coloring in the extrusion direction.

[0042]

Example 8 240.0 parts of agglomerated powder of ferrous hydroxide (yellow iron oxide) was mixed with 35.35 g of a copolymer of N-vinylpyrrolidone and N, N-dialkylaminoalkyl acrylate as a dispersant. 96.0 parts of a 0% ethanol solution and an equal weight mixture 46 of isopropanol and water as a medium.
It was charged into a bead mill together with 4.0 parts and dispersed while pulverized. 177 parts of tetraethoxysilane and 140 parts of isopropanol were charged into a reactor, and 400 parts of the yellow iron oxide dispersion was added dropwise over 10 minutes while stirring at room temperature, and stirring was continued for a while to obtain a uniform dispersion. Then, a catalyst solution comprising 36 parts of monoethanolamine and 200 parts of water was added dropwise over 30 minutes while stirring at room temperature, and stirring was further continued for 40 minutes to advance sol formation. The reaction temperature was raised to 80 ° C. by external heating to gel the sol for 30 minutes. A reaction reagent consisting of 33.0 parts of monomethyltrimethoxysilane and 20 parts of isopropanol was added, and stirring was continued at 80 ° C. for 60 minutes to perform a sol-gel reaction. After cooling, the reaction product was filtered and washed with water to remove the solvent, dispersant and catalyst. After drying at 120 ° C., the yield of the coated powder was 189.5 parts. This is substantially equivalent to a weight of 186.3 parts assuming that all of the silanes have been converted to silica and methyl-modified silica and coated with yellow iron oxide. Therefore, the composition of the coating powder is calculated to be carbon black 64.
5% by weight, 27.0% by weight of silica, 8.5% by weight of methyl-modified silica, and the proportion of the coating layer was 35.5% by weight. The obtained coated powder was pulverized with an impact pulverizer for 20 seconds. The particle size of the coated powder after pulverization was distributed between 0.1 and 10 μm, and the average particle size was 2.5 μm. Using the obtained crushed coated carbon black powder, a water surface floating test of Example 2, a paste fluidity test of Example 3, a dispersion stability test in oil of Example 4, and an emulsified foundation of Example 5 When a test equivalent to each test of the trial production test, the powder foundation trial production test of Example 6, and the resin melt-kneading extrusion test of Example 7 was performed, the same test was performed as in the case of the ground coated bengara powder obtained in Example 1. The performance was improved as compared with the comparative product, and satisfactory satisfactory results were obtained.

[0043]

Example 9 Carbon black (furnace black) was mixed with 240.0 parts of a dispersant polyvinyl butyral 1
A bead mill was charged with 400.0 parts of a 5.0% ethanol solution and 560.0 parts of ethanol as a medium, and carbon black was dispersed while being pulverized. In a reactor, 169.5 parts of tetraethoxysilane and 100.0 parts of isopropanol were charged, and 600.0 parts of the above carbon black dispersion was added dropwise over 10 minutes while stirring at room temperature. A dispersion was obtained. Then
A solution consisting of 36.0 parts of diethanolamine and 200 parts of water was added dropwise over 30 minutes while stirring at room temperature, and stirring was further continued for 40 minutes to advance sol formation.
And the sol was allowed to gel for 30 minutes. 140 parts of water
After dropwise addition over 5 minutes, a reaction reagent composed of 33.0 parts of monomethyltrimethoxysilane and 20 parts of isopropanol was added, and stirring was continued at 80 ° C. for 60 minutes to perform a sol-gel reaction. After cooling, the reaction product was filtered and washed with water to remove the solvent, dispersant and catalyst. After drying at 120 ° C., the yield of the coated powder was quantitative, corresponding to the conversion of the total amount of silanes to silica and methyl-modified silica to coat the carbon black. The composition of the coating powder was 64.5% by weight of carbon black, 27.0% by weight of silica, 8.5% by weight of methyl-modified silica, and the ratio of the coating layer was 35.0%.
5% by weight. The obtained coated powder was pulverized with an impact pulverizer for 20 seconds. The particle size of the coated powder after pulverization was distributed between 0.5 and 8 μm, and the average particle size was 2.5 μm.
Using the obtained crushed coated carbon black powder,
A test equivalent to each test of the water surface spray test of Example 2, the paste fluidity test of Example 3, the dispersion stability test in oil of Example 4, and the resin melt kneading extrusion test of Example 7 was performed. As in the case of the pulverized coated red bengal powder obtained in Example 1, the performance was improved as compared with the comparative product, and satisfactory satisfactory results were obtained.

[0044]

Example 10 A bead mill was charged with 12.0 parts of Herringdon Pink CN (CI Butt Red 1) together with 22.8 parts of a 15.0% ethanol solution of polyvinyl butyral as a dispersant and 65.2 parts of ethanol as a medium. ,
The pigment powder was dispersed while being ground. The reactor was charged with 56.0 parts of tetraethoxysilane and 360.0 parts of isopropanol.
And 135.0 parts of mica, 56.0 parts of the above red pigment dispersion was added dropwise over 10 minutes while stirring at room temperature, and stirring was continued for a while to obtain a uniform dispersion. Subsequently, a catalyst solution comprising 16.8 parts of diethanolamine and 22.5 parts of water was added dropwise over 30 minutes while stirring at room temperature, and stirring was further continued for 40 minutes to advance sol formation. The reaction temperature was raised by external heating to gel the sol for 30 minutes. Then, 270 parts of water was added dropwise over 15 minutes, then a reaction reagent consisting of 45.0 parts of monomethyltrimethoxysilane and 25 parts of ethanol was added, and stirring was further continued for 60 minutes to carry out a sol-gel reaction. The reaction product is filtered off after cooling,
The solvent, dispersant and catalyst were removed by washing with ethanol and water. After drying at 120 ° C., the yield of the coated powder was quantitative, corresponding to the conversion of all of the silanes to silica and methyl-modified silica. The obtained coated powder was pulverized with an impact pulverizer for 10 seconds. The average particle size of the coated powder after pulverization was 10.5 μm. This powder was found to have a structure in which a composite of a pigment and mica was coated with silica. Using the pulverized powder, a water surface spray test of Example 2, a paste fluidity test of Example 3, a dispersion stability test in oil of Example 4, an emulsification type foundation trial test of Example 5, and a When a test equivalent to each test of the powder foundation trial production test was performed, similar to the case of the ground coated bengal powder obtained in Example 1, the performance was improved and the satisfactory result was more satisfactory than the comparative product. I got it.

[0045]

Example 11 240.0 parts of phthalocyanine blue (CI Pigment Blue 15) powder was mixed with 400.0 parts of a 15.0% ethanol solution of a dispersant polyvinyl butyral,
And 560.0 parts of ethanol were charged into a bead mill, and the phthalocyanine blue powder was dispersed while being ground. A reactor was charged with 169.5 parts of tetraethoxysilane and 100 parts of isopropanol, and 600.0 parts of the phthalocyanine blue dispersion was added dropwise over 10 minutes while stirring at room temperature, and stirring was continued for a while to obtain a uniform dispersion. And Then, a liquid consisting of 36 parts of diethanolamine and 200 parts of water was added dropwise over 30 minutes while stirring at room temperature, and stirring was further continued for 40 minutes to advance sol formation. The reaction temperature was raised by external heating to gel the sol for 30 minutes. Water 1
After dropping 40 parts over 10 minutes, a reaction reagent consisting of 33.0 parts of monomethyltrimethoxysilane and 20 parts of isopropanol was added, and stirring was further continued for 60 minutes to carry out a sol-gel reaction. After cooling, the reaction product was separated by filtration and washed with ethanol or water to remove the solvent, dispersant and catalyst. The yield of coated powder after drying at 120 ° C. was quantitative, corresponding to the conversion of the total amount of silanes to silica and methyl-modified silica to coat phthalocyanine blue. The obtained coated powder was pulverized with an impact pulverizer for 20 seconds. The particle size of the coated powder after pulverization was distributed between 0.5 and 8 μm, and the average particle size was 2.6 μm. With the obtained ground coated phthalocyanine blue powder, a water surface spray test of Example 2, a paste fluidity test of Example 3, a dispersion stability test in oil of Example 4, and a trial production test of an emulsion type foundation of Example 5 When a test equivalent to the powder foundation trial production test of Example 6 was performed, the performance was improved and more satisfactory than the comparative product, as in the case of the ground coated bengal powder obtained in Example 1. I got the result.

[0046]

Example 12 Instead of the phthalocyanine blue powder in Example 11, one of the following pigments or laked dyes was used.
Using the seeds, the method of Example 11 was repeated for each. Brilliant Fast Scarlet (CI Pigment Red 24) Benzidine Yellow G (CI Pigment Yellow 14) Phthalocyanine Green (CI Pigment Green 7) Lisor Rubin BCA (CI Pigment Red 57-
1) In each case, quantitative two-layer coating was performed, and in the performance test of the coated powder, as in the case of Example 11, the performance was improved as compared with the comparative product, and satisfactory satisfactory results were obtained.

[0047]

Comparative Example 9 The method of Example 1 was repeated, except that the type of dispersant was changed to the Na salt of acrylic acid copolymerized acrylic resin. During the sol-gel reaction, agglomeration of Bengala particles progressed, and silica gel not partly involved in coating was formed. It is a powder having a rough feel due to coarse particles even after pulverization. The powder after removing the coarse particles is a paste fluidity test of Example 3, a dispersion stability test in oil of Example 4, and an oil dispersion test of Example 5. The emulsification type foundation trial test and the powder foundation trial test of Example 6 were conducted, but the improvement in paste fluidity and dispersion stability in oil due to coating was small, and the roughness and spread as cosmetics were improved. I was not able to admit.

[0048]

Comparative Example 10 The catalyst was changed from diethanolamine to ammonia, and 10.4 parts of 28% aqueous ammonia was replaced with 2 parts of ammonia.
The method of Example 11 was repeated using diluted with 00 parts of water. After the reaction, the filter paper was clogged, and the reaction product could not be separated by filtration. Observation of the solid content obtained by evaporation to dryness revealed that phthalocyanine blue particles with incomplete coating and silica gel particles were mixed. In a performance test, no improvement was observed in the paste fluidity and dispersion stability in oil of the powder, and the roughness and spreadability as cosmetics were not recognized.

[0049]

Comparative Example 11 The method of Example 10 was repeated, except that the type of the catalyst was changed to triethylamine. Observation of the obtained powder showed that silica gel particles were mixed. In a performance test, substantially no improvement in paste fluidity or dispersion stability in oil of the powder, and roughness or spread as a cosmetic was not recognized.

[0050]

The coated pigment powder of the present invention can be easily dispersed in a fluid medium, and the dispersed liquid has excellent fluidity and long-term dispersion stability. It is useful when applied to adhesives, resin molded products and the like. It is particularly suitable as a colorant in cosmetics because of its usefulness in use, such as no roughness and good stretch. Further, according to the method of the present invention, a useful coated pigment powder satisfying the above-mentioned properties at the same time can be produced.

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[Procedure amendment]

[Submission date] November 19, 1999 (1999.11.
19)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

Patent application title: Modified silica-coated pigment, process for producing the same and composition containing the same

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 3

[Correction method] Change

[Correction contents]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 7/12 C09D 7/12 Z C09J 201/00 C09J 201/00 F-term (Reference) 4C083 AB171 AB232 AC911 AC932 BB25 CC01 EE05 FF01 4J002 BB03X BB12X BC03X BE04W BE06W BF02W BG01W BG04X BG05X BG06X BG07W BH02W BJ00W CC18X CD00X CF00X CG00X CK02X DE036 DE096 DE116 DE136 DE146 EE056 EQ016 EU026 EX037 FA016 FB076 FB096 GB00 GH01 GJ01 4J037 AA02 AA08 AA15 AA17 AA21 AA25 AA30 CA23 CA24 CB16 CB23 CB26 CC15 CC16 CC17 CC30 DD23 DD24 EE03 EE28 EE43 FF15 FF30 4J038 EA011 KA08 KA15 4J040 DA021 DA101 DB031 DF041 EB131 EC001 ED091 EF001 EL021 HA136 HA306 HD30 KA07 KA35

Claims (5)

[Claims] 1. Zinc oxide, titanium oxide, cerium oxide,
And the surface of pigment particles selected from the group consisting of inorganic pigments and organic pigments excluding zirconium oxide is coated with a silica-based substance in an amount of 5% by weight or more and 100% by weight or less, and the inner layer of the coating layer is silica, Modified silica-coated pigment particles, wherein the outer layer is an alkyl-modified silica. 2. A composition comprising the modified silica-coated pigment particles of claim 1 blended in any one of a cosmetic, a paint, an adhesive, and a resin molded product. 3. Zinc oxide, titanium oxide, cerium oxide,
Pigment particles selected from the group consisting of inorganic pigments and organic pigments excluding zirconium oxide and an organic pigment are dispersed in an organic dispersion medium using a dispersant, and a tetraalkoxysilane is subjected to a sol-gel reaction in this dispersion system. A method for producing modified silica-coated pigment particles, comprising subjecting an alkylalkoxysilane to a sol-gel reaction in the dispersion. 4. The method according to claim 3, wherein the dispersant is an alkanolamine salt of an acrylic acid and / or methacrylic acid copolymer, an N-vinylpyrrolidone-N, N-dialkylaminoalkyl acrylate copolymer, A polymer selected from the group consisting of dialkyl sulfates of vinylpyrrolidone-N, N-dialkylaminoalkylacrylate copolymer, N-vinylpyrrolidone vinyl acetate copolymer, polyvinyl butyral, and methyl vinyl ether-dialkyl maleate copolymer 4. The method according to claim 3, wherein the dispersant is one or more kinds. 5. The method according to claim 3, wherein an alkanolamine is used as a reaction catalyst.