JP2008168175A - Method and device for manufacturing shelled micro-bubble - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for manufacturing shelled micro-bubbles (capsule of micro-bubble) stably for a long period of time. <P>SOLUTION: A gas phase is a dispersion phase and an oil phase is a continuous phase at the jointing point of a gas flow passage 35 and an oil phase flow passage 36, oil shells are formed outside the dispersion phase and become an aspherical particles extending in a string shape because of a high speed, the aspherical particles extending in a string shape are divided into small sizes by receiving shearing force by the flow of a water phase at a jointing point with a water phase flow passage 37 so that G/O/W emulsion is formed in which a gas phase with its outer periphery covered with the oil shells is a dispersion phase, and the water phase is a continuous phase. Then, the aspherical particles flowing through the water phase flow passage 37 reach a pool 38 and since the speed is quickly decreased they become spherical particles so that the shelled micro-bubbles (capsule of micro-bubble) are obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and apparatus for producing shelled microbubbles in which a fine gas phase is dispersed in an aqueous phase.

  Non-Patent Document 1 and Patent Document 1 propose a method (apparatus) for producing an emulsion in which the particle size of dispersed phase particles is constant.

  Non-Patent Document 1 discloses contents relating to generation of two-color polymer fine particles using a microchannel. In this prior art, a flow path for flowing a colored monomer (dispersed phase) to a glass substrate and a flow path for flowing a polyvinyl alcohol aqueous solution (continuous phase) that merges from both sides to the flow path are formed, and a merge portion that forms a Y shape The colored monomer is made into fine droplets by the shearing force of the polyvinyl alcohol aqueous solution.

  Patent Document 1 is a technique proposed by the present inventors, in which a microchannel that merges with each other is formed on one side of a substrate, a continuous phase is passed through one microchannel, and a dispersed phase is passed through the other microchannel. Immediately after the phase and the dispersed phase join together in a laminar flow state, the flow velocity of the continuous phase and the dispersed phase is sharply reduced to make the dispersed phase particles appear in the continuous phase.

Japanese Patent No. 3777427 Polymer preprints Japan Vol, 52, No, 5 (2003)

  When trying to manufacture microbubbles in which a fine gas phase is dispersed in an aqueous phase with the technique disclosed in Patent Document 1, the gas phase is suddenly dispersed in the aqueous phase, and the gas phases are combined in a short time. However, a stable microbubble state cannot be maintained for a long time.

  Specifically, in the case of a contrast agent, stable and monodispersed microbubbles are required, but a method and apparatus that can satisfy this has not been proposed, including Non-Patent Document 1.

In order to solve the above problems, a method for producing a shelled microbubble according to the present invention includes a non-spherical microbubble in which an oil shell is formed outside by joining a microchannel through which an oil phase flows into a microchannel through which a gas phase flows. After that, the microchannel is joined to the microchannel through which the water phase flows downstream from the joining point, and the non-spherical microbubbles in which the oil shell is formed are dispersed in the water phase. Then, the flow rate of the aqueous phase was rapidly decreased to form spherical microbubbles with an oil shell formed outside in the aqueous phase.
A preferable range of the flow ratio of the gas phase, the oil phase, and the water phase is 1: 0.05 to 0.5: 2 to 20.

  The microbubble manufacturing apparatus according to the present invention includes a substrate, on which a gas phase supply port, an oil phase supply port, an aqueous phase supply port, and a multiphase microbubble outlet are formed. A gas phase flow path having one end connected to the gas phase supply port, an oil phase flow path having one end connected to the oil phase supply port, and a water phase flow path having one end connected to the water phase supply port are formed on one side. The gas phase flow path and the oil phase flow path are merged, and the gas phase flow path and the water phase flow path are merged on the downstream side of the merging point. In the water phase flow path downstream of the junction with the phase flow path, an enlarged flow path that rapidly reduces the flow velocity of the water phase is formed.

  As a specific configuration, the merged flow channel and the water phase flow channel of the gas phase flow channel and the oil phase flow channel are orthogonally merged, and the oil phase is added to the gas phase flow channel upstream of the merge point. A configuration in which the flow paths merge is conceivable, and each merge point may be close or separated.

  According to the method for producing an emulsion according to the present invention, the gas phase can be stably maintained for a long time in the aqueous phase as fine microbubbles. Therefore, it can be effectively used as a contrast agent, a functional component, a drug, a gene delivery system, and the like.

  Further, according to the present invention, precise and flexible structure control of the core and shell, for example, the volume of the core (gas phase) and the thickness of the shell (oil layer or polymer film) can be freely changed by changing the supply flow rate ratio of each phase. Therefore, it is extremely effective for delivery systems such as drugs and genes.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of an apparatus used for producing a shelled microbubble according to the present invention, FIG. 2 is a view showing a surface of a substrate incorporated in the apparatus, and FIG. It is a figure explaining the process.

  The microbubble manufacturing apparatus stacks a transparent plate 2, a substrate 3, an O-ring 4 and a joint plate 5 in order from the bottom in the case 1, and a CCD for observing the generation state of shelled microbubbles below the transparent plate 2. A camera 6 is arranged.

  The joint plate 5 is formed with a gas phase supply hole 7, an oil phase supply hole 8, a water phase supply hole 9, and a shelled microbubble extraction hole 10. A gas phase supply source 11 is formed in the gas phase supply hole 7, An oil phase supply source 12 is connected to the oil phase supply hole 8, a water phase source 13 is connected to the water phase supply hole 9, and a recovery container 14 is connected to the microbubble extraction hole 10 formed into a shell.

The substrate 3 is made of, for example, a silicon substrate, and a flow path is formed on the silicon substrate by applying an integrated circuit forming technique (such as etching). Specifically, a gas phase supply port 31 formed at a position overlapping with the gas phase supply hole 7, an oil phase supply port 32 formed at a position overlapping with the oil phase supply hole 8, and the water phase supply hole 9 A water phase supply port 33 formed at an overlapping position and a shelled microbubble extraction port 34 formed at a position overlapping with the shelled microbubble extraction hole 10 are provided. A gas phase channel 35 having a thickness of about 100 μm and a depth of about 5 μm is formed toward the downstream side, and an oil phase channel 36 having a width of about 100 μm and a depth of about 5 μm is also downstream from the oil phase supply port 32. It is formed toward the side.

      The oil phase flow path 36 is provided on both sides of the gas phase flow path 35, and obliquely merges with the gas phase flow path 35 at an angle of 90 ° or less. The gas phase flow path where the oil phase merges further extends and merges with the water phase flow path 37. One end of the water phase flow path 37 is connected to the water phase supply port 33, and the other end is connected to the shelled microbubble outlet 34. The water phase channel 37 has a width of about 100 μm and a depth of about 5 μm, as described above.

      The upstream portions 35a and 36a from the confluence of the gas phase flow path 35 and the oil phase flow path 36 are increased in flow rate by narrowing the flow path width to about 50 μm and upstream of the confluence of the water phase flow path 37. The flow rate of the portion 37a is also increased by narrowing the channel width to about 50 μm.

      In addition, a pool 38 that reduces the flow velocity is formed in the downstream portion of the water phase flow path 37. In the illustrated example, the width of the pool 38 is the same as that of the upstream portion of the aqueous phase flow path 37, but the flow velocity may be drastically decreased by further increasing the width of the pool 38.

      As described above, the G / O emulsion in which the gas phase is the dispersed phase and the oil phase is the continuous phase is formed at the junction of the gas phase channel 35 and the oil phase channel 36. In the dispersed phase, an oil shell is formed on the outer side, but since the flow rate is high, non-spherical particles extending in a filament shape are formed.

      The gas phase extending in the form of a thread is divided into small portions by a shearing force due to the flow of the water phase at the junction with the water phase flow path 37, and the gas phase whose outer periphery is covered with an oil shell is the dispersed phase and the water phase. A G / O / W emulsion having a continuous phase is formed. Even in this case, the gas phase whose outer periphery is coated with an oil shell is non-spherical particles because the flow of the aqueous phase is fast.

      Thereafter, the non-spherical particles (dispersed phase) flowing through the water phase flow path 37 reach the pool 38, where the speed is rapidly reduced, so that the particles become spherical particles, and the desired shelled microbubbles are obtained.

(Example)
Using the shelled microbubble production system with the configuration shown in FIGS. 1 to 3, the water phase is different concentrations of SDS, such as air or nitrogen gas in the gas phase, soybean oil or tetradecane containing the surfactant in the oil phase. Preparation of microbubbles was attempted under the condition that the aqueous solution was used and the flow ratio of the gas phase, the oil phase, and the water phase was 1: 0.05 to 0.5: 2 to 20.

      FIG. 4 is a photograph showing how shelled microbubbles are produced in the above example, and it is observed that very uniform monodisperse shelled microbubbles are obtained.

      FIG. 5 is a photograph showing how a microbubble formed into a shell is produced in another example. In this embodiment, water is placed immediately downstream of the confluence of the gas phase channel 35 and the oil phase channel 36. A junction point with the phase flow path 37 is provided. It is observed that even in this other example, microbubbles formed into a very uniform monodisperse shell are obtained.

  The method and apparatus for producing shelled microbubbles according to the present invention are not only used in the food industry, medicine or cosmetics production, but also chromatographic carrier, polymerized toner, pigment, conductive spacer, metallic paint, environment Biodegradable microcapsules filled with fine particles for purification, flame retardants, catalysts, heat storage agents, antibacterial agents, pheromones, edible oils, bioactive substances, enzymes, aluminum flakes, mica, fertilizers, etc. Application to electrophoretic displays is conceivable.

Sectional view of an apparatus used for producing microbubbles according to the present invention The figure which shows the surface of the substrate which is built into the same Diagram explaining the process from gas phase to shelled microbubbles Photograph showing specific example of substrate Photograph showing another example of substrate

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Case, 2 ... Transparent board, 3 ... Board | substrate, 4 ... O-ring, 5 ... Joint plate, 6 ... CCD, 7 ... Gas-phase supply hole, 8 ... Oil-phase supply hole, 9 ... Water-phase supply hole, 10 DESCRIPTION OF SYMBOLS ... Multiphase micro bubble extraction hole, 11 ... Gas phase supply source, 12 ... Oil phase supply source, 13 ... Water phase source, 14 ... Recovery container, 31 ... Gas phase supply port, 32 ... Oil phase supply port, 33 ... Water Phase supply port, 34... Micro bubble outlet, 35... Gas phase channel, 36. Oil phase channel, 37. Water phase channel, 35 a, 36 a, 37 a.

Claims (4)

The microchannel through which the oil phase flows is joined to the microchannel through which the gas phase flows to form a non-spherical microbubble having an oil shell formed on the outside, and then the microchannel is placed in the water phase downstream from the junction. The non-spherical microbubbles in which the oil shell is formed are dispersed in the water phase, and then the flow rate of the water phase is drastically reduced by the enlarged flow path. A method for producing shelled microbubbles, characterized in that spherical microbubbles having an oil shell formed outside are formed. 2. The shelled microbubble according to claim 1, wherein a flow ratio of the gas phase, the oil phase, and the water phase is 1: 0.05 to 0.5: 2 to 20. Manufacturing method. An apparatus for producing a microbubble formed into a shell in which a gas phase covered with an oil shell is dispersed in an aqueous phase, the production apparatus comprising a substrate, the substrate comprising a gas phase supply port, an oil phase supply port, A water phase supply port and a microbubble take-out port are formed, and on one side of the substrate, a gas phase flow path connected to one end of the gas phase supply port, and an oil phase flow path connected to the oil phase supply port The water phase flow path is connected to one end of the water phase supply port, and the gas phase flow path and the oil phase flow path are merged, and the water phase flow path is merged downstream of the merge point. In addition, the water phase flow path downstream of the confluence of the gas phase flow path and the water phase flow path is formed with an enlarged flow path that rapidly reduces the flow rate of the water phase. Manufacturing equipment for shelled microbubbles. 4. The manufacturing apparatus for shelled microbubbles according to claim 3, wherein the gas phase flow path and the water phase flow path are orthogonal to each other.

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