JP5528777B2 - Water-dispersible pigment and its aqueous pigment dispersion - Google Patents

Description

  The present invention relates to water dispersibility used in water-dispersible pigment powder products such as water-based or emulsion-based cosmetics such as makeup cosmetics and sunscreen cosmetics, turbid bathing agents, water-based inks, and water-based paints. The present invention relates to an aqueous pigment dispersion containing a pigment and its water-dispersible pigment.

  In general, an inorganic pigment such as a metal oxide has a high affinity with water, although it depends on the surface potential. However, the pigment particles aggregate in the water due to surface activity and immediately settle. In order to further increase the affinity with water, it is also known that the pigment particle surface is treated with alumina or silica, but such treatment cannot suppress aggregation and sedimentation. In addition, some organic pigments and carbon are highly hydrophobic and are not easily dispersed in water, so it is extremely difficult to prepare an aqueous dispersion. In order to increase the hydrophilicity of carbon, an attempt is made to introduce a hydroxyl group or a carboxyl group on the surface by a graft reaction, or an attempt to introduce a hydrophilic functional group such as a hydroxyl group by plasma irradiation. Yes.

  On the other hand, in the titanium oxide used for the cloudy bathing agent, for example, as shown in Patent Document 1, it is coated with an acylated amino acid surfactant, and as shown in Patent Document 2, polyethylene is used. A coating with a dispersible nonionic surfactant such as glycol and fatty acid soap has been proposed. However, dispersibility is good where the bathing agent is used for a short time, but long-term dispersion stability cannot be obtained, or there is no chemical bond between the coating agent and the pigment to be coated. There is a problem that the coating stability is not excellent.

（式中、ｎとｋは１以上の整数、ｍは１〜３の整数であり、ｘとｙはそれぞれ１〜３の整数であり、ｘ＋ｙ＝４である。また、Ｒ_１，Ｒ_２は炭素数が１〜１０の炭化水素基である。） Further, Patent Document 3 proposes a pigment surface-treated with an alkoxysilane alone represented by the following general formula (1), but the pigment surface-treated with this alkoxysilane alone has an initial dispersion in water. However, there is a problem that long-term dispersion stability cannot be obtained.

(In the formula, n and k are integers of 1 or more, m is an integer of 1 to 3, x and y are each an integer of 1 to 3, and x + y = 4, and R ₁ and R ₂ are (It is a hydrocarbon group having 1 to 10 carbon atoms.)

  As described above, in the case of dispersing a pigment in water, in the case of a metal oxide, it is generally hydrophilic, but generally depends on its surface potential, but is generally neutral. Aggregation is easy because there is an isoelectric point in the region. For this reason, a technique for increasing the water dispersibility by coating with silica or alumina having an isoelectric point on the acidic side is common, but the water dispersibility is not sufficient due to its surface activity. In the case of carbon, it is possible to introduce a hydroxyl group or a carboxyl group by graft reaction or plasma irradiation to improve water dispersibility, but these methods are difficult to scale up industrially and are expensive. There is a problem of becoming. On the other hand, a method of coating titanium oxide with an acylated amino acid surfactant as used in a cloudy bathing agent, or coating with a water-dispersible nonionic surfactant such as polyethylene glycol and fatty acid soap, The method of surface treatment with an alkoxysilane simple substance as in formula (1) is not suitable for aqueous cosmetics, inks and paints because of poor water dispersion stability for a long time and poor coating stability. There is a point.

Japanese Patent Publication No. 7-17494 JP-A-3-294220 JP 2003-26958 A

  The present invention has been made to solve such problems, and is easily dispersed in water and an ionic aqueous solution, has excellent long-term water dispersion stability, and is surface-coated by a compound bond with a pigment. Accordingly, an object of the present invention is to provide a water-dispersible pigment having excellent coating stability and to provide a pigment aqueous dispersion containing the water-dispersible pigment.

（式中、ｎとｋは１以上の整数、ｍは１〜３の整数であり、ｘとｙはそれぞれ１〜３の整数であり、ｘ＋ｙ＝４である。また、Ｒ_１，Ｒ_２は炭素数が１〜１０の炭化水素基である。）
Ｓｉ（ＯＲ_３）_４ ・・・（２）
（Ｒ_３は炭素数が１以上の飽和炭化水素基を示す。） In order to achieve the above object, the water-dispersible pigment according to the first invention is:
Mixing the alkoxysilane compound represented by the alkoxysilane compound represented by the following following general formula (1) and the following general formula (2) in advance, each by mixing the mixture obtained and the pigment powder alkoxysilane compound Ri Na surface treated with the pigment powder to the general formula (1) and general formula (2), wherein the surface treatment amount der Rukoto than 50 wt% of the pigment powder of the alkoxysilane compound represented by It is what.

(In the formula, n and k are integers of 1 or more, m is an integer of 1 to 3, x and y are each an integer of 1 to 3, and x + y = 4, and R ₁ and R ₂ are (It is a hydrocarbon group having 1 to 10 carbon atoms.)
Si (OR ₃ ) ₄ (2)
(R ₃ represents a saturated hydrocarbon group having 1 or more carbon atoms.)

  The aqueous dispersion according to the second invention contains the water-dispersible pigment according to the first invention.

In the first invention, the surface treatment of the pigment powder of the general formula (1) (2) to the alkoxysilane compound represented, depending on the particle size of the pigment powder to be surface treatment, yo Ri Preferably, it is 0.5-50 mass%. When the amount is less than 0.5% by mass, sufficient water dispersibility may not be obtained depending on the pigment powder. When the amount exceeds 50% by mass, a by-product is likely to be generated due to a reaction between alkoxysilane compounds. Therefore, it is not preferable. In the second invention, the concentration of the pigment powder surface-treated with the alkoxysilane compound of the first invention in the aqueous dispersion is preferably 80% by mass or less. If it exceeds 80% by mass, the viscosity of the dispersion will increase remarkably, making handling difficult. On the other hand, the lower limit of the concentration should be set according to the application and is not particularly limited.

  According to the water-dispersible pigment according to the first invention, the alkoxysilane group part reacts with the pigment powder, and the polyethylene glycol group represented by the general formula (1) is introduced on the pigment powder surface. In addition, when this surface-treated pigment powder is used as an aqueous dispersion, the aqueous dispersion becomes a stable dispersion that hardly causes aggregation and sedimentation. In the surface treatment according to the present invention, the alkoxysilane compounds represented by the general formulas (1) and (2) react with and adhere to the pigment powder surface, so that the coating stability is very good.

  On the other hand, according to the aqueous dispersion according to the second invention, when preparing this aqueous dispersion, various dispersers can be used, and a dispersion having excellent dispersion stability can be obtained.

  Next, specific embodiments of the water-dispersible pigment and the pigment aqueous dispersion according to the present invention will be described.

In the water dispersible pigment according to the present invention, the alkoxysilane compound represented by the general formula (1) includes methoxy PEG-10 propyltrimethoxysilane.
Examples of the alkoxysilane compound represented by the general formula (2) include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, and tetraisobutoxysilane.

As a method of coating the surface of the pigment with these alkoxysilane compounds, there are the following methods.
First, a predetermined amount of an alkoxysilane compound to be coated on the pigment powder surface is dissolved in a suitable solvent so that the concentration is about 1 to 20% by mass. After adding 10% by mass or more of an alkaline aqueous solution to the solvent in this treating agent solution and stirring, this is put into a general mixer (for example, a Henschel mixer or a stirring reactor), and then the pigment powder to be coated. And stir for 1 hour or more. Thereafter, while stirring, the mixer is heated and decompressed as necessary to remove the solvent, and in some cases, the solvent is removed by filtration, followed by heat treatment and pulverization to obtain the desired water-dispersible pigment. The solvent used here is preferably a polar organic solvent capable of dissolving alkoxysilane such as water, isopropyl alcohol, acetone, methylene chloride. Further, as the alkali, alkalis used in the production of cosmetics such as ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate and the like can be used.
Thus, the surface of the water dispersible pigment powder is coated with the alkoxysilane represented by the general formulas (1) and (2).

  Here, the surface treatment amount of the alkoxysilane compound represented by the general formulas (1) and (2) to the pigment powder is 50% by mass or less, although it depends on the particle diameter of the pigment powder to be surface-treated. Preferably, it is 0.5 to 50% by mass. When the amount is less than 0.5% by mass, sufficient water dispersibility may not be obtained depending on the pigment powder. When the amount exceeds 50% by mass, a by-product is likely to be generated due to a reaction between alkoxysilane compounds. Therefore, it is not preferable.

As the pigment powder to be surface-coated according to the present invention, conventionally known pigment powders can be used, and their shapes (spherical, rod-like, needle-like, plate-like, indeterminate shape, scale-like, spindle-like, etc.) , Fine particles, pigment grades, etc.) and particle structures (porous, nonporous, etc.) can be used, such as inorganic powders, organic powders, surfactant metal salt powders, Colored pigments, pearl pigments, metal powder pigments and the like can be mentioned.
Specifically, as the inorganic powder, titanium oxide, zirconium oxide, zinc oxide, cerium oxide, magnesium oxide, barium sulfate, calcium sulfate, magnesium sulfate, calcium carbonate, magnesium carbonate, talc, mica, kaolin, sericite, Muscovite, synthetic mica, phlogopite, saucite, biotite, lithia mica, silicic acid, anhydrous silicic acid, aluminum silicate, magnesium silicate, magnesium aluminum silicate, calcium silicate, barium silicate, strontium silicate, Metal tungstate, hydroxyapatite, vermiculite, hydrite, bentonite, montmorillonite, hectorite, zeolite, ceramic powder, dicalcium phosphate, alumina, aluminum hydroxide, boron nitride, boron nitride, silica, etc. It is below.
Organic powders include polyamide powder, polyester powder, polyethylene powder, polypropylene powder, silicone resin powder, silicone elastomer powder, polystyrene powder, polyurethane powder, benzoguanamine powder, polymethylbenzoguanamine powder, polytetrafluoroethylene powder, poly Methyl methacrylate powder, cellulose, silk powder, nylon powder, 12 nylon, 6 nylon, acrylic powder, acrylic elastomer, styrene / acrylic acid copolymer, divinylbenzene / styrene copolymer, vinyl resin, urea resin, phenol resin, fluorine Resin, silicon resin, acrylic resin, melamine resin, epoxy resin, polycarbonate resin, microcrystalline fiber powder, den Down powder, and lauroyl lysine.
Surfactant metal salt powder (metal soap) includes zinc stearate, aluminum stearate, calcium stearate, magnesium stearate, zinc myristate, magnesium myristate, zinc cetyl phosphate, calcium cetyl phosphate, zinc sodium cetyl phosphate, etc. Can be mentioned.
In addition, as colored pigments, inorganic red pigments such as iron oxide, iron hydroxide and iron titanate, inorganic brown pigments such as γ-iron oxide, inorganic yellow pigments such as yellow iron oxide and ocher, black iron oxide, carbon Inorganic black pigments such as black, inorganic purple pigments such as manganese violet and cobalt violet, inorganic green pigments such as chromium hydroxide, chromium oxide, cobalt oxide and cobalt titanate, inorganic blue pigments such as bitumen and ultramarine blue, fine particle titanium oxide , Fine particle powders such as fine particle cerium oxide and fine particle zinc oxide, those obtained by lacquering tar dyes, those obtained by lacquering natural dyes, and synthetic resin powders obtained by combining these powders.
Examples of the pearl pigment include titanium oxide-coated mica, titanium oxide-coated mica, bismuth oxychloride, titanium oxide-coated bismuth oxychloride, titanium oxide-coated talc, fish scale foil, and titanium oxide-coated colored mica.
Examples of the metal powder pigment include powders selected from aluminum powder, copper powder, stainless steel powder, and the like.
Further, as tar pigments, Red No. 3, Red No. 104, Red No. 106, Red No. 201, Red No. 202, Red No. 204, Red No. 205, Red No. 220, Red No. 226, Red No. 227, Red No. 228 , Red 230, red 401, red 505, yellow 4, yellow 5, yellow 202, yellow 203, yellow 204, yellow 401, blue 1, blue 2, blue 201, blue No. 404, Green No. 3, Green No. 201, Green No. 204, Green No. 205, Orange No. 201, Orange No. 203, Orange No. 204, Orange No. 206, Orange No. 207 and the like.
Examples of natural pigments include pigments selected from carminic acid, laccaic acid, calsamine, bradylin, crocin and the like.

  The aqueous dispersion of the present invention can be prepared using a general disperser such as a disper or a homogenizer or a disperser such as a bead mill. More preferably, in preparing the dispersion, a suitable dispersant, for example, a nonionic surfactant polyoxyethylene lauryl ether (hereinafter referred to as POE (8) lauryl ether), POE (20) cetyl. Ether, POE (6) stearyl ether, POE (30) oleyl ether, POE (20) sorbitan monolaurate, POE (20) sorbitan monopalmitate, POE (20) sorbitan tristearate, POE (20) sorbitan monoole Ate, POE (20) sorbitan monostearate, decaglyceryl monolaurate, POE (40) hydrogenated castor oil, POE (10) octylphenol ether, POE (35) nonylphenol ether, polyethylene glycol, oxyethyleneoxypropiate If down the block polymer (60% average molecular weight ～5,400 ethylene oxide) or the like is blended 0.1-30 wt%, it is possible to obtain a more stable dispersion.

  In addition, as a compounding quantity of the said water dispersible pigment mix | blended with cosmetics, 0.1-100 mass% is preferable with respect to the total amount of cosmetics, More preferably, it is 1-60 mass%. Moreover, as a dosage form of cosmetics, conventionally well-known dosage forms, such as a two-layered form, a water-in-oil emulsion, an oil-in-water emulsion, a gel form, a spray, and a mousse form, can be used. In particular, bilayer, water-in-oil emulsions and gels are preferred for sunscreen applications, and for foundations, solid emulsions, gels, water-in-oil emulsions, oil-in-water emulsions, A mousse or the like is preferred.

  Next, specific examples of the water-dispersible pigment and the pigment aqueous dispersion according to the present invention will be described. In addition, this invention is not limited to the Example described below.

(Production Example 1)
2 kg by mass of methoxy PEG-10 propyltrimethoxysilane as an alkoxysilane of the above general formula (1) and tetraethoxysilane as an alkoxysilane of the above general formula (2) with respect to 1 kg of titanium oxide in a stirring reactor equipped with a blade 7% by mass and 28% ammonia water by 15% by mass were added to 1 kg of isopropyl alcohol to prepare a mixed solution. Next, this mixed solution was put into a stirring device in which 1 kg of titanium oxide was stirred, and stirred for 4 hours. Thereafter, the slurry was filtered to remove the solvent, and the remaining pigment cake was heat-treated at 80 ° C. to completely remove the solvent, and then pulverized with an atomizer to obtain a pigment surface-treated with the silane compound. Further, in the same manner as titanium oxide, surface-treated fine particle titanium oxide, fine particle zinc oxide, yellow iron oxide, and bengara were obtained.

(Production Example 2)
2 kg by mass of methoxy PEG-10 propyltrimethoxysilane as an alkoxysilane of the above general formula (1) and tetraethoxysilane as an alkoxysilane of the above general formula (2) with respect to 1 kg of titanium oxide in a stirring reactor equipped with a blade 18% by mass, 28% ammonia water 15% by mass was added to 1 kg of isopropyl alcohol to prepare a mixed solution. Next, this mixed solution was put into a stirring device in which 1 kg of titanium oxide was stirred, and stirred for 4 hours. Thereafter, the slurry was filtered to remove the solvent, and the remaining pigment cake was heat-treated at 80 ° C. to completely remove the solvent, and then pulverized with an atomizer to obtain a pigment surface-treated with the silane compound. Further, in the same manner as titanium oxide, surface-treated fine particle titanium oxide, fine particle zinc oxide, yellow iron oxide, and bengara were obtained.

(Production Comparative Example 1)
To 1 kg of titanium oxide in a stirring reactor equipped with a blade, 2% by mass of methoxy PEG-10 propyltrimethoxysilane as an alkoxysilane of the above general formula (1) was added to 1 kg of isopropyl alcohol to prepare a mixed solution. Next, this mixed solution was put into a stirring device in which 1 kg of titanium oxide was stirred, and stirred for 4 hours. Thereafter, the slurry was filtered to remove the solvent, and the remaining pigment cake was heat-treated at 80 ° C. to completely remove the solvent, and then pulverized with an atomizer to obtain a pigment surface-treated with the silane compound. Further, in the same manner as titanium oxide, surface-treated fine particle titanium oxide, fine particle zinc oxide, yellow iron oxide, and bengara were obtained.

(Production Comparative Example 2)
To 1 kg of titanium oxide in a stirring reactor equipped with a blade, 7% by mass of tetraethoxysilane as an alkoxysilane of the above general formula (2) and 15% by mass of 28% ammonia water are added to 1 kg of isopropyl alcohol, and the mixed solution is added. Produced. Next, this mixed solution was put into a stirring device in which 1 kg of titanium oxide was stirred, and stirred for 4 hours. Thereafter, the slurry was filtered to remove the solvent, and the remaining pigment cake was heat-treated at 80 ° C. to completely remove the solvent, and then pulverized with an atomizer to obtain a pigment surface-treated with the silane compound. Further, in the same manner as titanium oxide, surface-treated fine particle titanium oxide, fine particle zinc oxide, yellow iron oxide, and bengara were obtained.

(Production Comparative Example 3)
To 1 kg of titanium oxide in a stirring reactor equipped with a blade, 18% by mass of tetraethoxysilane as an alkoxysilane of the above general formula (2) and 15% by mass of 28% ammonia water are added to 1 kg of isopropyl alcohol, and the mixed solution is added. Produced. Next, this mixed solution was put into a stirring device in which 1 kg of titanium oxide was stirred, and stirred for 4 hours. Thereafter, the slurry was filtered to remove the solvent, and the remaining pigment cake was heat-treated at 80 ° C. to completely remove the solvent, and then pulverized with an atomizer to obtain a pigment surface-treated with the silane compound. Further, in the same manner as titanium oxide, surface-treated fine particle titanium oxide, fine particle zinc oxide, yellow iron oxide, and bengara were obtained.

Example 1
2 parts by mass of each silane compound surface-treated pigment prepared in Production Example 1 was put into 98 parts by mass of purified water and mixed and stirred with a homomixer to obtain a pigment aqueous dispersion. Thereafter, the pigment aqueous dispersion was transferred to a test tube and allowed to stand, and the dispersion behavior over time was visually evaluated.

(Example 2)
2 parts by mass of each silane compound surface-treated pigment prepared in Production Example 2 was put into 98 parts by mass of purified water, and mixed and stirred with a homomixer to obtain an aqueous pigment dispersion. Thereafter, the pigment aqueous dispersion was transferred to a test tube and allowed to stand, and the dispersion behavior over time was visually evaluated.

(Comparative Example 1)
2 parts by mass of each silane compound surface-treated pigment prepared in Production Comparative Example 1 was put into 98 parts by mass of purified water, and mixed and stirred with a homomixer to obtain an aqueous pigment dispersion. Thereafter, the pigment aqueous dispersion was transferred to a test tube and allowed to stand, and the dispersion behavior over time was visually evaluated.

(Comparative Example 2)
2 parts by mass of each silane compound surface-treated pigment prepared in Production Comparative Example 2 was put into 98 parts by mass of purified water, and mixed and stirred with a homomixer to obtain an aqueous pigment dispersion. Thereafter, the pigment aqueous dispersion was transferred to a test tube and allowed to stand, and the dispersion behavior over time was visually evaluated.

(Comparative Example 3)
2 parts by mass of each silane compound surface-treated pigment prepared in Production Comparative Example 3 was put into 98 parts by mass of purified water, and mixed and stirred with a homomixer to obtain an aqueous pigment dispersion. Thereafter, the pigment aqueous dispersion was transferred to a test tube and allowed to stand, and the dispersion behavior over time was visually evaluated.

(Comparative Example 4)
2 parts by mass of the untreated pigment used in Production Examples 1-2 and Production Comparative Examples 1-3 were charged into 98 parts by mass of purified water, and mixed and stirred with a homomixer to obtain a pigment aqueous dispersion. Thereafter, the pigment aqueous dispersion was transferred to a test tube and allowed to stand, and the dispersion behavior over time was visually evaluated.

Table 1 shows the observation results of the dispersion behavior of Examples 1 and 2 and Comparative Examples 1 to 4 after 24 hours from the mixing and stirring by the homomixer.

  As is clear from the results shown in Table 1, regarding the pigments obtained by coating the alkoxysilanes of the general formulas (1) and (2) at the same time, it can be seen that all the pigments have good water dispersibility ( See Examples 1 and 2.) On the other hand, regarding the pigment coated only with the alkoxysilane of the general formula (1), both a pigment exhibiting good water dispersibility and a pigment that settles within 1 hour after dispersion were confirmed (see Comparative Example 1). . Further, regarding the pigment coated with only the alkoxysilane of the general formula (2) and the uncoated treated pigment, all the pigments settled within 1 hour after dispersion (see Comparative Examples 2 to 4).

  A water-dispersible pigment and a water-dispersed pigment containing the water-dispersible pigment according to the present invention are highly dispersible makeup cosmetics such as makeup cosmetics, sunscreen cosmetics, and turbidity. It is suitable for application to water-dispersible pigment powder products such as bathing agents, water-based inks and water-based paints.

Claims (2)

Mixing the alkoxysilane compound represented by the alkoxysilane compound represented by the following following general formula (1) and the following general formula (2) in advance, each by mixing the mixture obtained and the pigment powder alkoxysilane compound Ri Na surface treated with the pigment powder to the general formula (1) and general formula (2), wherein the surface treatment amount der Rukoto than 50 wt% of the pigment powder of the alkoxysilane compound represented by Water dispersible pigment.

(In the formula, n and k are integers of 1 or more, m is an integer of 1 to 3, x and y are each an integer of 1 to 3, and x + y = 4, and R ₁ and R ₂ are (It is a hydrocarbon group having 1 to 10 carbon atoms.)
Si (OR ₃ ) ₄ (2)
(R ₃ represents a saturated hydrocarbon group having 1 or more carbon atoms.)   An aqueous dispersion containing the water-dispersible pigment according to claim 1.