JP2008080226A - Emulsion or suspension making method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an emulsion or suspension making method capable of making an emulsion or suspension of a uniform particle size. <P>SOLUTION: The method of making an emulsion or suspension having a controlled particle size includes steps of: causing water-insoluble inorganic fine particles having a mean particle size of 5-30 nm to adsorb a saturated adsorption amount of 80-100 mass% of water-soluble hydroxyalkyl alkyl cellulose and/or water-soluble alkyl cellulose in water; mixing it with a water-insoluble liquid; and stirring it by a stirring device. The emulsion or suspension having the uniform particle size in the narrow range of 1-10 μm, which is difficult to be controlled in the prior arts, can be obtained, and can be utilized in emulsification, suspension polymerization or the like for making an emulsion composition and a polymer compound in fields such as food and cosmetics. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is used in the manufacture of emulsified foods such as mayonnaise and salad dressing, emulsified cosmetics such as emulsions, and emulsified detergents such as shampoos and rinses, or monomers such as vinyl chloride, styrene, acrylic acid and acrylate esters in water. The present invention relates to a method for preparing an emulsion or suspension capable of obtaining an emulsion or suspension having a desired particle diameter in advance during suspension or emulsion polymerization.

  In general, as a method of dispersing oil or polymerizable monomer in water, the oil or monomer solution is mixed in an aqueous solution containing a low molecular surfactant and stirred, and the oil or monomer is dispersed by the emulsifying dispersion force of the surfactant. It is carried out by stabilizing the dispersion in water to a state called emulsification (emulsion).

  However, according to this method, the particle size of oil or monomer dispersed in water is dispersed as fine particles having a diameter of 1 μm or less due to the emulsifying action of a low molecular surfactant called micelle formation. In the application of the prepared emulsion, when the emulsified particles may be fine particles or when the size of the particle size does not matter, the preparation of the emulsion with the low molecular surfactant is performed without any problem.

  However, for example, by controlling the oil droplet size of the emulsified particles, such as dressing oil and edible cream, it is possible to prepare emulsions for foods with different throatiness and texture, or like polymerized toners. In addition, in order to obtain particles with good fluidity having a particle size on the order of 10 to several tens of μm, it is necessary to adjust the particle size of oil or monomer droplets in the prepared emulsion or suspension. Comes out.

  Conventionally, when adjusting the particle size of the droplets, the amount of the water-soluble polymer stabilizer added during the preparation of the emulsion is changed, the size of the mixing stirring blade, the stirring speed, and the stirring time are controlled. It was common. The size of the particles obtained by these methods has a distribution, and it has been difficult to obtain particles having a desired uniform particle size.

  On the other hand, a water-insoluble liquid is mixed in an aqueous solution containing a water-soluble hydroxyalkylalkylcellulose and / or alkylcellulose having a specific molecular weight, and the mixture is stirred for a certain period of time with a stirrer at a certain rotational speed to give an emulsion or suspension. JP-A-10-218901 (Patent Document 1) discloses a method for adjusting the particle diameter of a product to 10 to several tens of μm.

  However, the particle size of these emulsions is in the middle of a particle size range that can be easily formed with a low molecular weight surfactant of less than 1 μm and a range of 10 to several tens μm diameter that can be formed with a water-soluble polymer stabilizer. It was extremely difficult to stably obtain an emulsion having a particle size of 10 μm. In particular, when it is difficult to control the size and stirring speed of the mixing device, or when it is difficult to change these due to productivity, the particle size of the emulsion or suspension is in a narrow range of 1 to 10 μm. It was cumbersome and difficult to adjust.

JP-A-10-218901

  This invention is made | formed in view of the said situation, and it aims at providing the preparation method of the emulsion or suspension which can prepare the emulsion or suspension of the uniform particle size with uniform particle size. .

  As a result of intensive studies to achieve the above object, the present inventor has found that water-soluble hydroxyalkylalkylcellulose and / or alkylcellulose is saturated with water-insoluble inorganic fine particles having an average particle diameter of 5 to 30 nm in water. After adsorbing 80 to 100% by mass, a water-insoluble liquid is mixed and stirred with a stirrer to stabilize an emulsion or suspension having a uniform particle size in a narrow range of 1 to 10 μm in average particle size The present invention has been found and the present invention has been completed.

  The saturated adsorption amount is determined by dispersing water-insoluble inorganic fine particles in the water-soluble hydroxyalkylalkyl cellulose and / or water-soluble alkyl cellulose aqueous solution and stirring at room temperature (25 ° C.) to dissolve the water-insoluble inorganic fine particles in the water-insoluble inorganic fine particles. The saturated adsorption amount of the water-soluble hydroxyalkylalkyl cellulose and / or water-soluble alkyl cellulose with respect to the water-insoluble inorganic fine particles when the treatment of adsorbing the alkyl alkyl cellulose and / or the water-soluble alkyl cellulose is performed.

Accordingly, the present invention provides the following method for preparing an emulsion or suspension.
(1) Water-insoluble inorganic fine particles having an average particle diameter of 5 to 30 nm are adsorbed with water-soluble hydroxyalkylalkylcellulose and / or water-soluble alkylcellulose in water at 80 to 100% by mass of the saturated adsorption amount, and then water is added thereto. A method for preparing an emulsion or suspension having a controlled particle size, which comprises mixing an insoluble liquid and stirring with an agitator.
(2) The method for preparing an emulsion or suspension according to (1), wherein the water-insoluble inorganic fine particles are silica particles.
(3) The method for preparing an emulsion or suspension according to (1) or (2), wherein the water-insoluble liquid is an oil or a water-insoluble monomer.

  According to the present invention, it is possible to stably obtain an emulsion or suspension having a uniform particle size in a narrow range of an average particle size of 1 to 10 μm, which has conventionally been difficult to control. It can be used for emulsion or suspension polymerization when producing products and polymer compounds.

Hereinafter, the present invention will be described in detail.
In the present invention, water-insoluble inorganic fine particles having an average particle size of 5 to 30 nm are dispersed in an aqueous solution of water-soluble hydroxyalkylalkylcellulose and / or water-soluble alkylcellulose to thereby remove hydroxyalkylalkylcellulose and / or water-soluble alkylcellulose. A water-insoluble liquid as an inner phase, particularly an oil or water-insoluble monomer liquid, is emulsified or suspended in an aqueous phase as an outer phase adsorbed on insoluble inorganic fine particles, and an average of 70% by mass or more of the emulsion or suspension. The particle size can be stably controlled to 1 to 10 μm.

  Examples of the water-insoluble inorganic fine particles of the present invention include silica, alumina, silicon nitride, silicon carbide, lithium silicate, magnesium oxide, titanium oxide, and other oxides, nitrides, ceramics, and platinum, gold, silver, etc., which are less ionic. Any inorganic particles that are not soluble in metal or water can be used. The average particle diameter of the water-insoluble inorganic fine particles is 5 to 30 nm, and if it is outside this range, an emulsion or suspension having a particle diameter of 1 to 10 μm cannot be obtained. This is considered to be because when the water-insoluble inorganic fine particles coat a water-insoluble liquid like a protective phase, the particle size is too large or too small to provide a sufficient coated protective film.

  The average particle size of the water-insoluble inorganic fine particles can be measured in a state where the particles are dispersed in water by a dynamic light scattering particle size distribution measuring apparatus using laser light manufactured by Horiba, Ltd. or Hitachi, Ltd. . The method for producing these inorganic fine particles is not particularly limited. For example, in the case of silica particles, silicon tetrachloride is vapor-phase oxidized at 1,000 ° C. or higher in the presence of hydrogen and oxygen, and then by-product hydrochloric acid is removed. It can also be obtained by a wet method obtained by reacting sulfuric acid with sodium silicate called water glass and collecting precipitated silica particles. In any case, necessary pulverization and classification can be performed to adjust to the required average particle size.

  The addition amount of the water-insoluble inorganic fine particles of the present invention is preferably 1 to 2 parts by mass, particularly 1.1 to 1.5 parts by mass with respect to 100 parts by mass of the aqueous phase to be emulsified or suspended. Outside this range, it may be difficult to obtain an emulsion or suspension having an average particle diameter of 1 to 10 μm.

  Examples of the water-soluble hydroxyalkylalkylcellulose of the present invention include hydroxypropylmethylcellulose, hydroxyethylethylcellulose, hydroxyethylmethylcellulose, and the like, and examples of the water-soluble alkylcellulose include methylcellulose. These may be used alone or in combination of two or more.

  In addition, from the viewpoint that the water-soluble hydroxyalkylalkylcellulose or the water-soluble alkylcellulose has a water-soluble substitution ratio, for example, in the case of water-soluble hydroxyalkylalkylcellulose, the alkyl group is 20 to 31% by mass, particularly 22 to 30% by mass. %, The hydroxyalkyl group is preferably 4 to 30% by mass, particularly preferably 5 to 10% by mass. In the case of water-soluble alkyl cellulose, the alkyl group is preferably 24 to 31% by mass, particularly preferably 25 to 31% by mass.

  Furthermore, the molecular weight of the water-soluble hydroxyalkyl alkyl cellulose or the water-soluble alkyl cellulose is preferably 10,000 to 1,000,000, particularly preferably 50,000 to 700,000, and the viscosity of a 2% by weight aqueous solution at 20 ° C. is preferably 3 to 1,000,000 mPa · s. 15 to 8,000 mPa · s is preferable.

  Water-soluble hydroxyalkyl alkyl cellulose and water-soluble alkyl cellulose have a hydrophilic hydroxyalkyl group or a hydroxyl group and a hydrophobic alkyl group in the molecule, and have a surface activity. Is not as good as low molecular weight surfactants. When these water-soluble hydroxyalkyl alkyl celluloses and water-soluble alkyl celluloses are used, when the water-insoluble liquid, which is an oil component or a water-insoluble monomer, is emulsified or suspended, the emulsion or suspension is easily particles having a size of 10 μm or less. Although it does not have a diameter, the water-insoluble inorganic fine particles surround the water-insoluble liquid in a state of being strongly adsorbed by the surface active force to form an emulsion or suspension. One is unlikely to occur, and a stable state can be maintained.

  On the other hand, cellulose having a large number of hydrophilic groups such as hydroxyethyl cellulose has insufficient surface activity and does not form stable water-insoluble inorganic fine particles because it does not strongly adsorb oil and water-insoluble monomers to the surface. Not suitable for obtaining turbidity.

The amount of water-soluble hydroxyalkylalkylcellulose and water-soluble alkylcellulose adsorbed on water-insoluble inorganic fine particles differs from the concentration of water-soluble hydroxyalkylalkylcellulose or water-soluble alkylcellulose aqueous solution before and after dispersing water-insoluble inorganic fine particles (dCg / g), the mass of the water-soluble hydroxyalkylalkylcellulose or water-soluble alkylcellulose aqueous solution (Cg), and the mass of the dispersed water-insoluble inorganic fine particles (Mg); Can do.
(C x dC) / M (g / g)

Here, the difference between the concentration of the water-soluble hydroxyalkylalkyl cellulose or the water-soluble alkylcellulose aqueous solution before and after dispersing the water-insoluble inorganic fine particles can be determined by the following two methods.
First, 5 to 20% by mass of water-insoluble inorganic fine particles of water-soluble hydroxyalkylalkylcellulose or water-soluble alkylcellulose aqueous solution having a known concentration is stirred for 15 hours or more at room temperature of 25 ° C. and then dispersed. In this method, the liquid is centrifuged at 5,000 rpm or more, 20 parts by mass of the supernatant solution is taken, dried at 105 ° C. for 4 hours, and the mass of the dried product is measured.
Second, the refractive index of the supernatant solution after centrifugation is measured from the refractive index measured in advance with a refractometer or the like that is required to change the refractive index of the solution according to the concentration of the solution. This is a method for measuring the concentration of a water-soluble hydroxyalkylalkylcellulose or an aqueous solution of a water-soluble alkylcellulose.

  Then, the amount of adsorption is determined by changing the concentration of the aqueous solution of water-soluble hydroxyalkylalkylcellulose or water-soluble alkylcellulose before dispersing the water-insoluble inorganic fine particles. The concentration before dispersing the water-insoluble inorganic fine particles is determined so that the adsorbed amount is 80 to 100% by mass of the saturated adsorption amount that has not changed, and the water-soluble hydroxyalkylalkyl cellulose or water-soluble added to the water-insoluble inorganic fine particles is determined. The concentration of the aqueous solution of the functional alkylcellulose is determined. If this concentration is too thin and less than 80% by mass of the saturated adsorption amount, the average particle size of the emulsion or suspension does not become 1 to 10 μm, and the average particle size becomes large.

  The concentration when the water-soluble hydroxyalkylalkylcellulose and water-soluble alkylcellulose of the present invention are added to the aqueous aqueous solution is determined by the amount adsorbed on the water-insoluble inorganic fine particles as described above. Adjust as an aqueous solution that exists in a liquid to be mixed at a ratio of 0.08 to 0.20 g, particularly 0.10 to 0.13 g with respect to 1 g of water-insoluble inorganic fine particles to be adjusted, or as a solution concentration higher than this amount After mixing with water-insoluble inorganic fine particles to obtain a saturated adsorption amount, centrifugation may be performed to remove the supernatant solution, and after washing with water, the water-insoluble liquid may be mixed and emulsified or suspended.

  As the water-insoluble liquid of the present invention, any water-insoluble liquid can be used as long as it does not dissolve in water.For example, oils such as saturated or unsaturated fatty acids such as silicone oil and salad oil, aliphatic hydrocarbons such as hexane and butane, Examples thereof include water-insoluble monomers such as aromatic hydrocarbons such as benzene and toluene. In addition, it is preferable that it is a liquid which has a viscosity of several hundred mPa * s or less as a viscosity which is disperse | distributed when mixing and stirring in water of a water-insoluble liquid.

  The water-insoluble liquid of the present invention is 74% by volume or less, preferably 50% by volume or less, based on an aqueous solution of an aqueous phase in which water-soluble hydroxyalkylalkylcellulose and / or water-insoluble inorganic fine particles adsorbed with alkylcellulose are dispersed. Preferably, they are mixed and emulsified or suspended so as to be 30% by volume or less. If this ratio is large, the water-insoluble liquid after emulsifying or suspending becomes difficult to close-pack, and the water-insoluble liquid may be united and easily separated. The lower limit is preferably 10% by volume or more, particularly preferably 20% by volume or more.

  The diameter and shape of the stirring blade in the stirring device used for emulsification or suspension of the present invention, the stirring speed and time are not particularly limited as long as the effects of the present invention are not impaired, but about several hundred to 10,000 rpm. It is preferable that the set stirring speed is maintained at a high speed and the water-insoluble liquid is formed into droplets by stirring to be dispersed in the aqueous phase to be emulsified or suspended.

  In the emulsification or suspension method, an emulsion or suspension is usually prepared by stirring with a high-speed stirring device at a fixed rotation speed for a fixed time.

  The average particle size of the emulsion or suspension in the present invention means the droplet diameter of water-insoluble liquid droplets dispersed in an emulsified or suspended state in the aqueous phase. The water-soluble hydroxyalkylalkylcellulose and / or water-insoluble inorganic fine particles adsorbed by the water-soluble alkylcellulose added to the aqueous phase provide the effect that the desired emulsified or suspended particle size can be stably obtained for a long time. The The average particle diameter of the emulsion or suspension can be measured with an optical microscope, a flow type particle image analyzer manufactured by Simex or a Coulter counter manufactured by Peckman Coulter, Inc.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited to these Examples.

[Examples 1 to 5, Comparative Examples 1 to 4]
100 parts by mass of water is added to 0.5 parts by mass of various water-soluble hydroxyalkylalkylcelluloses and water-soluble alkylcelluloses shown in Table 1, and 1.0 part by mass of various water-insoluble inorganic fine particles shown in Table 1 is added. The mixture was added in a 200 ml beaker and stirred for 15 hours at 500 rpm with a chemical stirrer chip having a length of about 2 cm and a width of about 0.5 cm. Thereafter, the dispersion was centrifuged at 10,000 rpm, 20 parts by mass of the supernatant solution was taken and dried at 105 ° C. for 4 hours, and the part by mass (S) of the dried product was measured. Thereafter, the amount of each water-soluble hydroxyalkylalkylcellulose and water-soluble alkylcellulose adsorbed on various water-insoluble inorganic fine particles was determined according to the following formula.
{(0.5 × 100) − (20 × S × 5)} / 1.0

  Similarly, with respect to a solution prepared by adding 0.3 to 0.8 parts by mass of various water-soluble hydroxyalkylalkylcelluloses and water-soluble alkylcelluloses with respect to 100 parts by mass of water, When the adsorption amounts of hydroxyalkyl alkyl cellulose and water-soluble alkyl cellulose were determined, the adsorption amount (saturated adsorption amount) that hardly changes even when the concentration of the aqueous solution was increased in any case was 0.1 to 0.13 g / It was found to be 1 g of silica, ie 0.15 to 0.20 g / 1.5 g of silica.

  Next, the amounts shown in Table 1 were added to various water-soluble hydroxyalkylalkylcelluloses and water-soluble alkylcelluloses calculated in consideration of the saturated adsorption amount with respect to 100 parts by mass of water to prepare an aqueous solution. To the prepared aqueous solution, the amount of water-insoluble inorganic fine particles shown in Table 1 is added, and stirred at 500 rpm for 15 hours in a chemical stirrer chip having a length of about 2 cm and a width of about 0.5 cm in a 300 ml beaker at room temperature of 25 ° C. did. Thereafter, the amount of water-insoluble liquid shown in Table 1 was added, and the emulsion was mixed with S-25-N-25F type as a stirring blade with an ultra disperser stirring device manufactured by Granular Yamato Kagaku Co., Ltd. for 30 minutes. The average particle size of the suspension was measured with a 500 × microscope. Table 1 shows the observation results regarding whether or not the number of particles having an average particle diameter of 1 to 10 μm when measuring about 100 particle diameters is 70% or more and the observed average particle diameter.

  Table 1 also shows the measurement results obtained by allowing the prepared emulsion or suspension to stand for one month and observing the average particle size of the emulsion or suspension again with a microscope.

  From Table 1, water-insoluble inorganic fine particles are dispersed and adsorbed in an aqueous solution containing various water-soluble hydroxyalkylalkylcelluloses and water-soluble alkylcelluloses in an amount corresponding to 80% by mass or more of the saturated adsorption amount. The average particle size of the emulsion or suspension obtained by adding and stirring was 70% by mass or more and was 1 to 10 μm, and was stable even after 1 month.

  On the other hand, when various water-soluble hydroxyalkyl alkyl celluloses are not added (Comparative Examples 1 and 4), when water-insoluble inorganic fine particles are not added (Comparative Example 2), or when water-soluble hydroxyalkyl cellulose is added (Comparative Example 3). No emulsion or suspension having an average particle diameter of 1 to 10 μm was observed, or the proportion thereof was 60% by mass or less.

エアロジルシリカ１３０（デグッサ社製、ＡＥＲＯＳＩＬ シリカ １３０、平均粒径約１６ｎｍ）
エアロジルシリカ３８０（デグッサ社製、ＡＥＲＯＳＩＬ シリカ ３８０、平均粒径約７ｎｍ）
エアロジルシリカ５０（デグッサ社製、ＡＥＲＯＳＩＬ シリカ ５０、平均粒径約３０ｎｍ）
メチルセルロース（信越化学工業（株）製、ＳＭ−１００：２０℃，２質量％水溶液粘度 １００ｍＰａ・ｓ）
ヒドロキシプロピルメチルセルロース（信越化学工業（株）製、６０ＳＨ−４００：２０℃，２質量％水溶液粘度 ４００ｍＰａ・ｓ）
ヒドロキシエチルメチルセルロース（信越化学工業（株）製、ＳＥＷ−６０Ｔ：２０℃，２質量％水溶液粘度 ６５，０００ｍＰａ・ｓ）
ヒドロキシエチルセルロース ＳＥ−ＴＹＬＯＳＥ社製（Ｈ２００ＹＧ４：２０℃，２質量％水溶液粘度 ４００ｍＰａ・ｓ）
シリコーンオイル（信越化学工業（株）製、ジメチルシリコーンオイル ＫＦ９６，粘度 １ｍＰａ・ｓ）
綿実油（日清製油（株）製、綿実油）
＊×５００倍光学顕微鏡による視野内の粒子１００個中、平均粒径１〜１０μｍのものをカウントした。

Aerosil silica 130 (Degussa, AEROSIL silica 130, average particle size of about 16 nm)
Aerosil silica 380 (Degussa, AEROSIL silica 380, average particle size of about 7 nm)
Aerosil silica 50 (Degussa, AEROSIL silica 50, average particle size of about 30 nm)
Methylcellulose (manufactured by Shin-Etsu Chemical Co., Ltd., SM-100: 20 ° C., 2% by weight aqueous solution viscosity 100 mPa · s)
Hydroxypropyl methylcellulose (manufactured by Shin-Etsu Chemical Co., Ltd., 60SH-400: 20 ° C., 2% by weight aqueous solution viscosity 400 mPa · s)
Hydroxyethyl methylcellulose (manufactured by Shin-Etsu Chemical Co., Ltd., SEW-60T: 20 ° C., 2 mass% aqueous solution viscosity 65,000 mPa · s)
Hydroxyethyl cellulose manufactured by SE-TYLOSE (H200YG4: 20 ° C., 2% by weight aqueous solution viscosity 400 mPa · s)
Silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., dimethyl silicone oil KF96, viscosity 1 mPa · s)
Cottonseed oil (manufactured by Nisshin Oil Co., Ltd., cottonseed oil)
* Of the 100 particles in the field of view by a 500 × optical microscope, those having an average particle diameter of 1 to 10 μm were counted.

[Example 6]
As water-insoluble inorganic fine particles, 7.5 parts by mass of alumina sol 520 (solid content: 20% by mass) manufactured by Nissan Chemical Industries, Ltd. having an average particle diameter of about 20 nm, 100 parts by mass of water, and water-soluble hydroxyalkylalkylcellulose are listed in Table 1. Add 92.5 parts by mass of a solution obtained by dissolving 0.25 parts by mass of hydroxypropylmethylcellulose, add the silicone oil described in Table 1 as water-insoluble inorganic fine particles, and stir to determine the average particle size of the emulsion or suspension. It was measured. 70% by mass or more had an average particle size of 1 to 10 μm and was stable even after one month.

[Comparative Examples 5 and 6]
The average particle size of the emulsion or suspension was measured in the same manner as in Example 6 except that the water-insoluble inorganic fine particles having an average particle size of 1 nm and 100 nm were used as the water-insoluble inorganic fine particles.

Claims (3)

  Water-insoluble inorganic fine particles having an average particle size of 5 to 30 nm are adsorbed with water-soluble hydroxyalkylalkylcellulose and / or water-soluble alkylcellulose in water at 80 to 100% by mass of the saturated adsorption amount, and then water-insoluble liquid is added thereto. A method for preparing an emulsion or suspension having a controlled particle size, which is mixed and stirred by a stirring device.   The method for preparing an emulsion or suspension according to claim 1, wherein the water-insoluble inorganic fine particles are silica particles.   The method for preparing an emulsion or suspension according to claim 1 or 2, wherein the water-insoluble liquid is an oil or a water-insoluble monomer.