JP2010142725A - Method for producing oil droplet dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an oil droplet dispersion having an oil droplet volume average particle size of 100-1,000 μm in high productivity by a stable operation. <P>SOLUTION: The method for producing the oil droplet dispersion includes a step in which a liquid oily component is combined with a flowing aqueous component made of a polymer aqueous solution with a viscosity of 10-200 mPa s to make the surroundings be covered with the aqueous component, and a step of obtaining the oil droplet dispersion having an oil droplet volume average particle size of 100-1,000 μm by circulating the combined aqueous and oily components through a microchannel 22. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing an oil droplet dispersion.

  When an oil droplet dispersion having a volume average particle size of oil droplets of 100 μm or more is used in cosmetics or the like, it is required that the oil droplet diameter distribution has a high monodispersity in order to visually recognize the oil droplets. As a method for producing an oil droplet dispersion satisfying this requirement, a method using a microchannel has been proposed.

  Patent Documents 1 and 2 disclose oil droplets in which an aqueous component and an oily component are circulated in one of a pair of microchannels provided so as to cross each other and the oily component is dispersed in the aqueous component at the intersection. A method for producing a dispersion is disclosed.

Non-Patent Document 1 discloses that a PDMS (polyester) produced by a special method is prepared by circulating an oil component and an aqueous component in the former of an outer tube and an inner tube provided concentrically, respectively, and merging them together. A method for producing a water droplet dispersion to be circulated through a microchannel (orifice) of an apparatus made of (dimethylsiloxane) is disclosed.
International Publication 2002/068104 Pamphlet JP 2004-122107 A Shoji Takeuchi et al., Advanced Materials 2005, 17, No. 8, 1067-1072

  However, in the methods disclosed in Patent Documents 1 and 2, oil droplets are generated in a state where the oil component is in contact with the wall surface of the microchannel, so that the wall surface is likely to get wet with the oil component if performed continuously for a long time, As a result, it may be difficult to control the oil droplet diameter.

  In addition, the method disclosed in Non-Patent Document 1 is a method in which aqueous components are merged so that the periphery is covered with an oil component composed of hexadecane, and since the viscosity of the oil component is low, from the viewpoint of stable operation. It is necessary to operate with a small flow rate, and high productivity cannot be obtained.

  Therefore, in order to achieve both stable operation and high productivity, a large number of microchannels must be provided side by side. In this case, there are concerns about problems such as high apparatus costs and complicated maintenance.

  An object of the present invention is to provide a method capable of producing an oil droplet dispersion having a volume average particle diameter of oil droplets of 100 to 1000 μm with stable operation and high productivity.

The method for producing the oil droplet dispersion of the present invention comprises:
A step of merging a liquid oily component with a flowing aqueous component comprising a polymer aqueous solution having a viscosity of 10 to 200 mPa · s so that the periphery is covered with the aqueous component;
Obtaining an oil droplet dispersion in which the volume average particle diameter of the oil droplets is 100 to 1000 μm by circulating a combined fluid of the aqueous component and the oil component in the microchannel;
Is provided.

  According to the present invention, since the viscosity of the aqueous component is 10 to 200 mPa · s, it is possible to spontaneously generate oil droplets based on the interfacial tension, and the coalescence and convection of oil droplets due to collisions between oil droplets and the like. Oil droplets are prevented from being refined due to the action of high shearing force due to the generation of vortices, and the oily component is circulated through the microfluidic channel through a combined fluid in which the periphery of the oily component is covered with an aqueous component. Since it does not contact the wall surface of the microchannel, stable oil droplets can be generated even if the flow rate is large. That is, an oil droplet dispersion having a volume average particle diameter of oil droplets of 100 to 1000 μm can be produced with stable operation and high productivity.

  Hereinafter, embodiments will be described.

(Production system A for oil droplet dispersion)
FIG. 1 shows a manufacturing system A for an oil droplet dispersion.

  This oil droplet dispersion manufacturing system A is composed of a micromixer 100 and an accompanying part such as a liquid supply system.

  The micromixer 100 includes a pair of liquid inflow portions 101 and a single liquid outflow portion 102.

  One of the pair of liquid inflow portions 101 is connected to a first supply pipe 32a extending from the first storage tank 31a for storing an aqueous component. The first supply pipe 32a includes a first pump 33a for circulating the aqueous component, a first flow meter 34a for detecting the flow rate of the aqueous component, and a first filter 35a for removing contaminants of the aqueous component. A first pressure gauge 36a for detecting the pressure of the aqueous component is attached to a portion between the first flow meter 34a and the first filter 35a in order from the upstream side. Each of the first pump 33a, the first flow meter 34a, and the first pressure gauge 36a is electrically connected to the flow controller 37.

  A second supply pipe 32b extending from the second storage tank 31b for storing the oil component is connected to the other of the pair of liquid inflow portions 101. The second supply pipe 32b has a second pump 33b for circulating the oil component, a second flow meter 34b for detecting the flow rate of the oil component, and a second filter 35b for removing contaminants of the oil component. A second pressure gauge 36b for detecting the pressure of the oil component is attached to a portion between the second flow meter 34b and the second filter 35b. Each of the second pump 33b, the second flow meter 34b, and the second pressure gauge 36b is electrically connected to the flow controller 37.

  The flow rate controller 37 is configured to be capable of inputting the set flow rate and set pressure of the aqueous component and incorporates an arithmetic element, and includes the set flow rate information of the aqueous component, the flow rate information detected by the first flow meter 34a, and The first pump 33a is configured to control the operation based on pressure information detected by the first pressure gauge 36a. Similarly, the flow controller 37 is configured to be able to input a set flow rate and a set pressure of the oil component, and the set flow information of the oil component, the flow information detected by the second flow meter 34b, and the second pressure meter 36b. The second pump 33b is configured to control the operation based on the pressure information detected in step (b).

  The liquid outflow portion 102 of the micromixer 100 is connected to the product reservoir 38. The product reservoir 38 may be provided with cooling means such as a heat exchanger and a temperature control jacket.

  2A to 2C show an example of a specific configuration of the micromixer 100. FIG.

  The micromixer 100 includes a liquid circulation pipe 10 provided so as to constitute a part of a pipe and a liquid merging / dispersing portion 20 provided continuously on the liquid outflow side.

  The liquid flow pipe 10 is configured in a double pipe structure of a large diameter pipe 12 and a single small diameter pipe 13 that is introduced and inserted concentrically therewith. In this liquid circulation pipe 10, there are two liquid flow paths, an aqueous component flow path 11 a inside the large diameter pipe 12 and outside the small diameter pipe 13, and an oil component flow path 11 b inside the small diameter pipe 13. It is comprised so that it may extend in parallel mutually inside a pipe | tube and it follows a length direction. The inflow portion of the large diameter pipe 12 is configured as one liquid inflow portion 101, and the inflow portion of the small diameter tube 13 exposed to the outside of the liquid circulation tube 10 is configured as the other liquid inflow portion 101. Such a micromixer 100 having the liquid flow pipe 10 having a double-pipe structure has a simple apparatus configuration and is easy to maintain by disassembly and cleaning.

  Each of the large-diameter pipe 12 and the small-diameter pipe 13 has a circular channel cross-sectional shape. However, it is not particularly limited to this, and may be, for example, a semicircular shape, an elliptical shape, a semielliptical shape, a square shape, a rectangular shape, a trapezoidal shape, a parallelogram shape, a star shape, an indefinite shape, or the like. The large diameter tube 12 has an inner diameter D1 of, for example, 3 to 12 mm, and the small diameter tube 13 has an inner diameter D2 of, for example, 1 to 5 mm.

  The liquid merging / dispersing part 20 forms an internal region continuous with the liquid outflow end of the liquid circulation pipe 10, and this internal region constitutes the liquid merging part 21. The liquid junction 21 has a length L1 in the liquid flow direction of, for example, 0.5 to 5 mm, and a capacity of, for example, 0.001 to 4 mL.

  In the liquid merging / dispersing part 20, a micro flow path 22 provided continuously to the liquid merging part 21 is perforated, and a flow path expanding part 23 is provided continuously to the micro flow path 22. The flow passage expanding portion 23 is configured in the liquid outflow portion 102. Here, in the present application, the “micro channel” refers to a channel whose minimum value of the hydraulic equivalent diameter d at each location of the channel is 0.05 mm or more and 1 mm or less.

  The portion continuing to the micro flow path 22 in the liquid confluence portion 21 may have a configuration in which the flow path diameter is discontinuously reduced as shown in FIG. 3A, and as shown in FIG. 3B. The flow path diameter may be continuously reduced to a Venturi tube. In the latter case, the length L2 of the portion is, for example, 1 to 30 mm.

  The microchannel 22 has a circular channel cross-sectional shape. However, it is not particularly limited to this, and may be, for example, a semicircular shape, an elliptical shape, a semielliptical shape, a square shape, a rectangular shape, a trapezoidal shape, a parallelogram shape, a star shape, an indefinite shape, or the like.

The micro channel 22 preferably has a hydraulic equivalent diameter d of 0.3 to 1.0 mm, or a channel area s of 0.05 to 1.0 mm ² , and the channel area s of 0.05 to 0. More preferably, it is 6 mm ² . The microchannel 22 preferably has a channel length l of 0.6 to 150 mm. Further, in the microchannel 22, from the viewpoint that a stable laminar flow can be obtained in the channel, the channel length / hydraulic equivalent diameter (l / d) is preferably 3 to 500, and preferably 30 to 300. More preferably.

  As for the material of the micro flow path 22, those having physical properties that are difficult to wet with oil components are preferable from the viewpoint of generating stable oil droplets. Specifically, materials with a contact angle of 90 ° or less with fluorine resin such as PTFE (polytetrafluoroethylene) and PFA (copolymer of tetrafluoroethylene and perfluoroalkoxyethylene), and water such as stainless steel and glass. Is mentioned. Among these, it is more preferable to use glass from the viewpoint of monodispersity of the particle diameter of the obtained droplet.

  The micro channel 22 is formed to extend in the same direction as the direction in which the aqueous component channel 11a and the oil component channel 11b extend. However, it is not particularly limited to this, and it may be formed to extend in a direction different from the extending direction thereof. The microchannel 22 may be formed so as to extend in the lateral direction, may be formed so as to extend in the vertical direction, and may be formed so as to extend in an oblique direction. Note that the microchannel 22 formed so as to extend in the up-down direction or the oblique direction may have a liquid flow direction from top to bottom, or from bottom to top.

  The channel expanding portion 23 has a circular channel cross-sectional shape. However, it is not particularly limited to this, and may be, for example, a semicircular shape, an elliptical shape, a semielliptical shape, a square shape, a rectangular shape, a trapezoidal shape, a parallelogram shape, a star shape, an indefinite shape, or the like. The flow path expanding portion 23 has an inner diameter D3 of, for example, 1.5 to 12 mm, or is an open system.

  The portion extending from the micro flow path 22 in the flow path expanding section 23 may have a configuration in which the flow path diameter is discontinuously expanded as shown in FIG. 4A, and as shown in FIG. 4B. The channel diameter may be continuously expanded into a venturi shape, and further, as shown in FIG. 4 (c), the microchannel 22 extending vertically downward is continuous with the channel expanding section 23 opened. It may be a configuration. In the case of the configuration shown in FIG. 4B, the length L3 of the portion is, for example, 20 mm or less.

  A recovery pipe extending toward the product reservoir 38 may be connected to the flow path expanding portion 23, and an alkali addition means may be provided in the recovery pipe.

  In addition, in this example, it was set as the structure with one small diameter pipe | tube 13, However, As shown to Fig.5 (a) and (b), the structure with a plurality of small diameter pipes 13 may be sufficient.

(Method for producing oil droplet dispersion)
Next, an oil droplet dispersion manufacturing method using the oil droplet dispersion manufacturing system A will be described.

  This method for producing an oil droplet dispersion is such that a liquid oily component is joined to a flowing aqueous component composed of a polymer aqueous solution having a viscosity of 10 to 200 mPa · s so that the periphery is covered with the aqueous component. Is circulated through the microchannel 22 to obtain an oil droplet dispersion having a volume average particle diameter of oil droplets of 100 to 1000 μm.

<Aqueous component and oil component>
The aqueous component is a polymer aqueous solution having a viscosity of 10 to 200 mPa · s, preferably 20 to 100 mPa · s. The viscosity is measured using a B-type viscometer under the condition of a rotational speed of 60 r / m (see JIS Z8803, K7117-1, etc.). When the aqueous component is in such a viscosity range, spontaneous oil droplet generation based on interfacial tension is possible, and high oil concentration due to oil droplet coalescence and convection vortex generation due to collision between oil droplets or the like is possible. The refinement of oil droplets due to the action of shearing force is suppressed, and stable oil droplets can be generated.

  Here, the water-soluble polymer contained in the aqueous component may be a synthetic polymer or a natural polymer. As such a water-soluble polymer, those having a carboxyl group are preferable from the viewpoint of ease of dissolution in water, ease of viscosity adjustment, and ease of treatment to increase the viscosity of the product as necessary. Examples thereof include acrylic polymers having a group, polysaccharides such as sodium alginate and carboxymethyl cellulose. Examples of the acrylic polymer include (acrylic acid / alkyl acrylate (C10-30)) copolymer (for example, trade name: CARBOPOL manufactured by Nikko Chemicals), acrylic acid / alkyl methacrylate copolymer (for example, A product name: PEMULEN manufactured by Nikko Chemicals Co., Ltd., an acrylic acid copolymer (for example, product name: ACULYN manufactured by Rohm & Haas), and the like. Among these, an acrylic polymer having a carboxyl group is preferable from the viewpoint that thickening and stabilization can be easily achieved by adjusting the pH of the obtained oil droplet dispersion, and acrylic acid / alkyl methacrylate copolymer is preferable. The combination (for example, trade name: PEMULEN manufactured by Nikko Chemicals) is most preferable. The water-soluble polymer may be composed of a single species or a plurality of species.

  Although the density | concentration of water-soluble polymer will not be specifically limited if the viscosity of said aqueous component is implement | achieved, For example, it is 0.02-5 mass%.

  The water is, for example, ion exchange water, distilled water or the like.

  The aqueous component may contain an organic solvent miscible with water, preservatives, salts, surfactants, and other active ingredients as long as the viscosity and interfacial tension are not adversely affected.

  The oily component is a liquid that does not mix with water. The oily component may be a solid at room temperature, and in that case, the oily component is handled as a liquid by setting the temperature to the melting point or higher during operation.

  The oil component preferably has physical properties such that the interfacial tension with water is 10 mN / m or more and the viscosity is 40 mPa · s or less. Specific examples of such an oil component include dimethicone, cyclic silicone, squalane, vegetable oil, ester oil and the like for liquids at room temperature, and palm oil, beef tallow and carbon numbers of 14 to 22 for solids at room temperature. Examples include mineral oils such as higher alcohols and ceresin. The oil component may be composed of a single species or a mixture of a plurality of species.

  In addition, the oil component may contain a lipophilic surfactant or an organic solvent.

<Manufacture of oil droplet dispersion>
When the manufacturing system A for the oil droplet dispersion is operated, the first pump 33a moves the first flow meter 34a and the first filter 35a in order from the first storage tank 31a through the first supply pipe 32a. Then, the liquid is continuously supplied to one liquid inflow portion 101 of the micromixer 100. The first flow meter 34 a sends the detected flow rate information of the aqueous component to the flow rate controller 37. Further, the first pressure gauge 36 a sends the detected pressure information of the first pressure gauge 36 a to the flow rate controller 37.

  The second pump 33b continues the oil component from the second storage tank 31b through the second supply pipe 32b to the one liquid inflow portion 101 of the micromixer 100 through the second flow meter 34b and the second filter 35b in order. To supply. The second flow meter 34 b sends the detected flow rate information of the oil component to the flow controller 37. Further, the second pressure gauge 36 b sends the detected pressure information of the second pressure gauge 36 b to the flow rate controller 37.

  Subsequently, the flow rate controller 37 sets the aqueous component based on the set flow rate information and the set pressure information of the aqueous component, the flow rate information detected by the first flow meter 34a, and the pressure information detected by the first pressure meter 36a. The first pump 33a is operated and controlled such that the set flow rate and the set pressure are maintained. At the same time, the flow controller 37 sets the oil component based on the set flow information and set pressure information of the oil component, and the flow information detected by the second flow meter 34b and the pressure information detected by the second pressure meter 36b. The second pump 33b is operated and controlled so that the set flow rate and the set pressure are maintained.

  In the micromixer 100, after the aqueous component that has flowed through the aqueous component flow channel 11a and the oily component that has flowed through the oily component flow channel 11b have joined the oily component so that the periphery is covered with the aqueous component in the liquid merging portion 21. These combined fluids flow into the microchannel 22, and in the microchannel 22, the combined fluid flows in a laminar flow state and flows out to the channel expanding portion 23.

  Here, about the temperature of an aqueous component, it is preferable to set it as 5-95 degreeC, for example. The temperature of the oil component is a temperature at which the oil component is in a liquid state, and is preferably set to, for example, 5 to 95 ° C. At this time, the entire oil droplet dispersion production system A may be heated as necessary.

  About each pressure setting of an aqueous component and an oil-based component, it is preferable to make it the pressure of liquid feeding become 0.005-0.5 Mpa, for example.

  Regarding the respective flow rate settings of the aqueous component and the oil component, the total flow rate of the aqueous component and the oil component flowing through the micro flow path 22 is set to 0.2 to 20 L / h from the viewpoint of productivity and flow stability. Preferably, it is more preferable to set it as 0.3-8 L / h. In addition, the volume ratio of the oil component to the aqueous component is preferably set to oil component / aqueous component = 1/99 to 40/60 from the viewpoint of obtaining a preferable volume average particle size and particle size distribution of the oil droplets. Is preferable, and 3/97 to 20/80 is more preferable.

  An oil droplet dispersion liquid having a volume average particle diameter of oil droplets of 100 to 1000 μm (preferably 100 to 600 μm) flows out from the flow path expanding portion 23 which is the liquid outflow portion 102 of the micromixer 100, which is the product. It is collected in the reservoir 38.

  At this time, the oil droplet dispersion liquid flowing out from the liquid outflow portion 102 may be cooled as necessary. Further, the oil droplet dispersion may be thickened in order to improve the dispersion stability of the obtained oil droplet dispersion. Such viscosity adjusting operation is performed, for example, by using an acrylic polymer having a carboxyl group as a water-soluble polymer contained in the aqueous component in a recovery tube or product reservoir 38 extending from the flow path expanding portion 23 toward the product reservoir 38. When used, adjust the pH by adding an aqueous sodium hydroxide solution, or add a polyvalent metal salt such as an aqueous zinc carbonate solution when sodium alginate is used as the water-soluble polymer. Can be done.

  Below, the test evaluation which manufactured and manufactured the oil-drop dispersion liquid of various structures is demonstrated. The outline is also shown in Table 1.

(Manufacture of oil droplet dispersion)
<Example 1>
An oil droplet dispersion manufacturing system A having the same configuration as that shown in FIG. 1 equipped with a micromixer 100 made of SUS316 having a double tube structure as shown in FIG. 6A was used. Note that gear pumps (manufactured by Zenith) were used as the first and second pumps 33a and 33b.

In the liquid mixer 10, the micromixer 100 has an inner diameter D1 of the large diameter pipe 12 of 4.4 mm, an outer diameter of the small diameter pipe 13 of 3.2 mm, and an inner diameter D2 of 1.6 mm. The micromixer 100 has a configuration in which the portion of the liquid merging / dispersing part 20 that is continuous with the micro flow path 22 in the liquid merging part 21 has a structure in which the diameter of the flow path is discontinuously reduced. The portion continuing from the path 22 also has a configuration in which the flow path diameter is discontinuously enlarged. The microchannel 22 has a circular channel cross-sectional shape, an inner diameter d of 0.5 mm (a channel area s of 0.20 mm ² ), a channel length l of 30 mm, and a channel length / inner diameter. (L / d) is 60. Moreover, the flow path expansion part 23 is formed in a circular cross section of the flow path, and the inner diameter D3 is 4.4 mm.

  A 0.11 mass% aqueous polymer solution of acrylic acid / alkyl methacrylate copolymer (trade name: PEMULEN TR-2 manufactured by Nikko Chemicals Co., Ltd.) was prepared and prepared as an aqueous component in the first storage tank 31a. This aqueous polymer solution had a viscosity of 40 mPa · s measured using a B-type viscometer under the condition of a rotational speed of 60 r / m. In addition, squalane was prepared as an oil component in the second storage tank 31b. At this time, the temperature of each of the aqueous component and the oily component was adjusted to 20 ° C.

  And with respect to the micromixer 100 temperature-controlled at 20 degreeC, the said aqueous component and oil-based component are the sum of the volume ratio (oil-based component / aqueous component) = 12/88 and the water-based component and oil-based component which distribute | circulate the microchannel It supplied so that a flow volume might be 2.0 L / h.

  After collecting the oil droplet dispersion recovered from the micromixer 100 in a sample bottle, 0.5M potassium hydroxide was added dropwise thereto to adjust the pH to 7.0, thereby increasing the viscosity of the oil droplet dispersion. Example 1 was adopted.

<Example 2>
Oil droplet dispersion obtained in the same manner as in Example 1 except that the channel length l of the microchannel 22 of the micromixer 100 is 100 mm and the channel length / inner diameter (l / d) is 200. The liquid was designated as Example 2.

<Example 3>
The microchannel 22 of the micromixer 100 has a circular channel cross-sectional shape, an inner diameter d of 0.5 mm (a channel area s of 0.20 mm ² ), a channel length l of 2 mm, and a flow The point formed in the shape of an orifice as shown in FIG. 6B where the path length / inner diameter (l / d) is 4, and the micro-flux 100 are mixed with the aqueous component and the oil component. The oil droplet dispersion liquid obtained in the same manner as in Example 1 except that the total flow rate of the aqueous component and the oily component flowing through No. 22 was supplied to 3.0 L / h was defined as Example 3.

<Example 4>
The same as Example 3 except that the aqueous component and the oily component were supplied to the micromixer 100 so that the total flow rate of the aqueous component and the oily component flowing through the microchannel 22 was 6.0 L / h. The oil droplet dispersion obtained in this manner was designated as Example 4.

<Example 5>
The oil droplet dispersion obtained in the same manner as in Example 1 was carried out except that the microchannel 22 of the micromixer 100 was made of glass and the inner diameter D3 of the channel enlarged portion 23 was 6.0 mm. Example 5 was adopted. In addition, the flow path expansion part 23 was comprised with the transparent vinyl hose connected following the micro flow path 22. FIG.

<Example 6>
Oil droplet dispersion obtained in the same manner as in Example 5 except that the channel length l of the microchannel 22 of the micromixer 100 is 100 mm and the channel length / inner diameter (l / d) is 200. The liquid was designated as Example 6.

<Example 7>
The same as Example 6 except that the aqueous component and the oil component were supplied to the micromixer 100 so that the total flow rate of the aqueous component and the oil component flowing through the micro flow path 22 was 3.0 L / h. The oil droplet dispersion obtained in this manner was used as Example 7.

<Example 8>
The microchannel 22 of the micromixer 100 is obtained in the same manner as in Example 7 except that the microchannel 22 has a configuration that is continuous with the channel expanding portion 23 that extends vertically downward and is released as shown in FIG. The oil droplet dispersion was designated as Example 8.

<Example 9>
The microflow channel 22 of the micromixer 100 is formed in a venturi tube shape as shown in FIG. 6D in which the innermost diameter of the microflow channel 22 is 0.34 mm (a continuous flow channel is formed in the micro flow channel 22 in the liquid junction 21. The length L2 of the portion to be reduced is 24 mm, the length of the microchannel 22 is 40 mm, and the length L3 of the portion where the channel continuously expands from the microchannel 22 in the channel expanding portion 23 is 16 mm), and An oil droplet dispersion liquid obtained in the same manner as in Example 7 except that the inner diameter D3 of the flow path expanding portion 23 is 4.0 mm was defined as Example 9.

<Example 10>
An oil droplet dispersion liquid obtained in the same manner as in Example 2 except that the microchannel 22 of the micromixer 100 is made of polytetrafluoroethylene (PTFE) was used as Example 10.

<Example 11>
The inner diameter d of the microchannel 22 of the micromixer 100 is 0.8 mm (the channel area s is 0.50 mm ² ), the channel length l is 50 mm, and the channel length / inner diameter (l / d) is 62. As an aqueous component, 0.5M potassium hydroxide was added dropwise to a 0.6% by mass polymer aqueous solution of an acrylic acid copolymer (trade name: ACULYN 22 manufactured by Rohm & Haas Co., Ltd.) as an aqueous component, and the pH 6.4 The above-mentioned aqueous component and oily component were added to the micromixer 100 in terms of the volume ratio (oil component / aqueous component) = 6/94 and micro. An oil droplet dispersion obtained in the same manner as in Example 1 except that the total flow rate of the aqueous component and the oily component flowing through the flow path 22 was 0.5 L / h was used as Example 11. .

<Example 12>
As an aqueous component, a 0.15% by mass aqueous polymer solution of acrylic acid / alkyl methacrylate copolymer (trade name: PEMULEN TR-2 manufactured by Nikko Chemicals Co., Ltd.) having a viscosity of 92 mPa · s was used. Example 11 except that the aqueous component and the oily component were supplied to the micromixer 100 so that the total flow rate of the aqueous component and the oily component flowing through the microchannel 22 was 2.0 L / h. An oil droplet dispersion obtained in the same manner as in Example 12 was designated as Example 12.

<Example 13>
The microchannel 22 of the micromixer 100 has a circular channel cross-sectional shape, an inner diameter d of 0.3 mm (a channel area s is 0.07 mm ² ), a channel length l of 1 mm, and a flow The path length / inner diameter (l / d) is formed in an orifice shape as shown in FIG. 6B with 3.3, and the inner diameter D3 of the flow path expanding portion 23 is 1.6 mm. In addition, Example 12 except that the aqueous component and the oil component were supplied to the micromixer 100 so that the total flow rate of the aqueous component and the oil component flowing through the microchannel 22 was 0.5 L / h. An oil droplet dispersion liquid obtained in the same manner was designated as Example 13.

<Comparative Example 1>
When water having a viscosity of 1 mPa · s was used as an aqueous component and the pH was not adjusted after collection into a sample bottle, the same operation as in Example 6 was performed. Almost all of the oil droplets were already united, and oil and water were separated after collection into the sample bottle.

<Comparative example 2>
As an aqueous component, 0.5M potassium hydroxide was added dropwise to a 0.11% by mass polymer aqueous solution of an acrylic acid / alkyl methacrylate copolymer (trade name: PEMULEN TR-2, manufactured by Nikko Chemicals), and the viscosity was 300 mPa · When the same operation as in Comparative Example 1 was carried out except that a material adjusted so as to be s was used, most of the oily components were not separated into droplets but were separated from oil and water.

(Test evaluation method)
<Volume average particle size of oil droplets>
About each of Examples 1-13, the volume average particle diameter and area average particle diameter of the oil droplet were calculated | required using the laser diffraction / scattering type particle size distribution measuring apparatus (LA-910 by Horiba Ltd.).

<Dispersity>
For each of Examples 1 to 13, the degree of dispersion was determined by calculating the ratio of the volume average particle diameter to the area average particle diameter (volume average particle diameter ÷ area average particle diameter).

(Test evaluation results)
Table 1 shows the test results.

  The volume average particle size of the oil droplets is 387 μm in Example 1, 368 μm in Example 2, 313 μm in Example 3, 131 μm in Example 4, 433 μm in Example 5, 405 μm in Example 6, 405 μm in Example 7, and 349 μm in Example 7. Example 8 was 390 μm, Example 9 was 169 μm, Example 10 was 399 μm, Example 11 was 162 μm, Example 12 was 252 μm, and Example 13 was 282 μm.

  The dispersity is 1.59 in Example 1, 1.58 in Example 2, 1.66 in Example 3, 2.12 in Example 4, 1.33 in Example 5, 1. 21, Example 7 is 1.32, Example 8 is 1.17, Example 9 is 1.61, Example 10 is 1.46, Example 11 is 1.33, Example 12 is 1.37, Example 13 was 1.42.

  The present invention is useful for a method for producing an oil droplet dispersion used in cosmetics and the like.

It is a figure which shows the structure of the manufacturing system of an oil droplet dispersion liquid. It is (a) longitudinal cross-sectional view which shows a micromixer, (b) IIB-IIB cross-sectional view in Fig.2 (a), (c) IIC-IIC cross-sectional view in Fig.2 (a). (A) And (b) is a longitudinal cross-sectional view of the upstream part of a liquid confluence | merging part. (A)-(c) is a longitudinal cross-sectional view of the downstream part of a liquid confluence | merging part. It is the (A) longitudinal cross-sectional view which shows the modification of a micromixer, and (b) VB-VB cross-sectional view in Fig.5 (a). (A)-(d) is a figure which shows the structure of the micromixer used in the Example.

Explanation of symbols

22 Microchannel

Claims (3)

A step of merging a liquid oily component with a flowing aqueous component comprising a polymer aqueous solution having a viscosity of 10 to 200 mPa · s so that the periphery is covered with the aqueous component;
Obtaining an oil droplet dispersion in which the volume average particle diameter of the oil droplets is 100 to 1000 μm by circulating a combined fluid of the aqueous component and the oil component in the microchannel;
A method for producing an oil droplet dispersion comprising: The flow path area of the microchannel is 0.05 to ¹ mm ² , and the total flow rate of the aqueous component and the oil component flowing through the microchannel is 0.2 to 20 L / h. A method for producing the described oil droplet dispersion.   The method for producing an oil droplet dispersion according to claim 1, wherein the polymer contained in the aqueous polymer solution has a carboxyl group.

Images