WO2022186014A1

WO2022186014A1 - Ultrafine bubble liquid generation method and ultrafine bubble liquid generation device

Info

Publication number: WO2022186014A1
Application number: PCT/JP2022/007365
Authority: WO
Inventors: 秀彰小林
Original assignee: Idec株式会社
Priority date: 2021-03-04
Filing date: 2022-02-22
Publication date: 2022-09-09
Also published as: JP2022134808A

Abstract

This ultrafine bubble (UFB) liquid generation method comprises: a step (step S11) for dispersing, in water, an additive that is a hydrophilic food additive to generate a subject liquid; and a step (steps S12 to S14) for mixing air with the pressurized subject liquid to generate UFBs of the air within the subject liquid, thereby generating a UFB liquid that contains UFBs. The additive is a polyglycerin fatty acid ester or a sucrose fatty acid ester. This makes it possible to generate a UFB liquid that is safe for humans, that contains UFBs in a high concentration, and that has high long-term stability of UFBs.

Description

ULTRAFINE BUBBLE LIQUID GENERATION METHOD AND ULTRAFINE BUBBLE LIQUID GENERATOR

TECHNICAL FIELD The present invention relates to a technology for generating ultrafine bubble liquid.
[Reference to related application]
This application claims the benefit of priority from Japanese Patent Application JP2021-034222 filed on March 4, 2021, the entire disclosure of which is incorporated herein.

In recent years, liquids containing bubbles with a diameter of 1 mm (millimeter) or less have been used in various fields. Recently, liquids containing bubbles (ultra-fine bubbles) with a diameter of less than 1 μm (micrometers) have attracted attention in various fields. Ultra-fine bubbles (hereinafter also referred to as “UFB”) are different from millibubbles, which are bubbles with a diameter of 1 mm or more, and microbubbles, which are bubbles with a diameter of 1 μm to 1 mm, and float and disappear due to buoyancy. can exist for long periods of time in liquids.

Recent research has found that depending on the type of liquid in which UFB is generated, it may be difficult to generate UFB at a high concentration. The inventors of the present application have found that UFB is relatively difficult to generate in liquids with high electrical conductivity, such as grinding liquids used for grinding, and added a small amount of surfactant to the liquid. proposed a technique for suitably generating UFB (Japanese Patent Application Laid-Open No. 2020-99862 (Document 1)). In addition, International Publication No. 2018/097019 (Document 2) proposes a technique of adding fatty acids or fatty vitamins and hydrocarbons to water as production accelerators in order to promote the production of UFB. .

By the way, in recent years, liquids containing UFB (hereinafter also referred to as "UFB liquids") have also been used for applications such as showers and beauty treatments that come in contact with the human skin or enter the mouth. When the UFB liquid is used for the human body or the like in this way, substances such as the above-mentioned hydrocarbons, which may be harmful to the human body when taken orally, should be used as additives for promoting the generation of UFB. can't. Further, when the liquid for generating the UFB liquid is water or the like, it is not easy to evenly dissolve or disperse the hydrophobic additive in the liquid.

On the other hand, it is known to add orally ingestible hydrophilic food additives for the purpose of improving the foaminess of carbonated beverages. Therefore, it is not envisaged to use this technology for the purpose of producing UFB in high concentration and allowing it to exist in liquids for a long period of time.

The present invention is directed to a method for producing an ultra-fine bubble liquid, and aims to produce a UFB liquid that is safe for the human body, contains a high concentration of UFB, and has high long-term stability of UFB. .

A method for producing an ultra-fine bubble liquid according to a preferred embodiment of the present invention comprises: a) a step of dispersing an additive, which is a hydrophilic food additive, in water to produce a target liquid; and mixing with the target liquid to generate ultra-fine bubbles of the gas in the target liquid to generate an ultra-fine bubble liquid containing the ultra-fine bubbles. Said additive is polyglycerol fatty acid ester or sucrose fatty acid ester.

According to the present invention, it is possible to produce a UFB liquid that is safe for the human body, contains a high concentration of UFB, and has high long-term stability of UFB.

Preferably, the concentration of the ultra-fine bubbles in the ultra-fine bubble liquid measured immediately after generation is 100 million/mL or more. Preferably, the concentration of the ultra-fine bubbles in the ultra-fine bubble liquid 5 days after the measurement immediately after the generation is 50% or more of the concentration of the ultra-fine bubbles in the ultra-fine bubble liquid measured immediately after the generation. be.

Preferably, the HLB value of the additive is 9.0 or higher.

Preferably, the concentration of the additive in the target liquid is 10 mg/L or less.

A method for producing an ultra-fine bubble liquid according to another preferred embodiment of the present invention includes the steps of: a) dispersing an additive, which is a hydrophilic food additive, in water to produce a target liquid; and mixing with the target liquid to generate ultra-fine bubbles of the gas in the target liquid to generate an ultra-fine bubble liquid containing the ultra-fine bubbles. The concentration of the ultra-fine bubbles in the ultra-fine bubble liquid measured immediately after generation is 100 million/mL or more. The concentration of the ultra-fine bubbles in the ultra-fine bubble liquid 5 days after the measurement immediately after the generation is 50% or more of the concentration of the ultra-fine bubbles in the ultra-fine bubble liquid measured immediately after the generation.

Preferably, in the step b), the gas is pressurized and dissolved in the target liquid to generate a pressurized liquid, and the ultrafine bubbles are precipitated from the pressurized liquid to generate the ultrafine bubble liquid.

Preferably, the ultra-fine bubble liquid is supplied into the oral cavity during tooth whitening.

The present invention is also directed to an ultra-fine bubble liquid generator. An ultra-fine bubble liquid generating apparatus according to a preferred embodiment of the present invention includes a mixing unit that mixes a gas and a pressurized target liquid to generate a mixed fluid, and in the mixed fluid, the target liquid contains the gas and a generation unit that generates an ultra-fine bubble liquid containing the ultra-fine bubbles by generating the ultra-fine bubbles. The target liquid is a liquid in which an additive, which is a hydrophilic food additive, is dispersed in water. Said additive is polyglycerol fatty acid ester or sucrose fatty acid ester.

An ultra-fine bubble liquid generating device according to another preferred embodiment of the present invention includes a mixing unit that mixes a gas and a pressurized target liquid to generate a mixed fluid, and in the mixed fluid, the gas in the target liquid and a generation unit that generates an ultra-fine bubble liquid containing the ultra-fine bubbles by generating the ultra-fine bubbles. The target liquid is a liquid in which an additive, which is a hydrophilic food additive, is dispersed in water. The concentration of the ultra-fine bubbles in the ultra-fine bubble liquid measured immediately after generation is 100 million/mL or more. The concentration of the ultra-fine bubbles in the ultra-fine bubble liquid 5 days after the measurement immediately after the generation is 50% or more of the concentration of the ultra-fine bubbles in the ultra-fine bubble liquid measured immediately after the generation.

The above-mentioned and other objects, features, aspects and advantages will become apparent from the detailed description of the present invention given below with reference to the accompanying drawings.

1 is a cross-sectional view of an ultra-fine bubble liquid generator according to one embodiment; FIG. FIG. 4 is a diagram showing the flow of generation of ultra-fine bubble liquid. FIG. 4 is an enlarged cross-sectional view of the mixing nozzle; FIG. 4 is an enlarged cross-sectional view of an ultra-fine bubble generating nozzle;

FIG. 1 is a diagram showing the configuration of an ultra-fine bubble liquid generator 1 according to one embodiment of the present invention. In FIG. 1, the configuration of a part of the ultra-fine bubble liquid generating device 1 is drawn in cross section. "Ultra-fine bubbles" are bubbles with a diameter of less than 1 µm (micrometers), and are also called nanobubbles. In the following description, ultra-fine bubbles are also referred to as "UFB". Further, the ultra-fine bubble liquid, which is a liquid containing UFB, is also called "UFB liquid", and the ultra-fine bubble liquid generator is also called "UFB liquid generator".

The UFB liquid generation device 1 is a device that mixes liquid and gas to generate UFB liquid, which is a liquid containing UFB of the gas. The UFB liquid generated by the UFB liquid generation device 1 is supplied, for example, into the human oral cavity and used for tooth whitening. In tooth whitening, generally, the higher the concentration of UFB in the UFB solution, the better the whitening effect. The UFB liquid may be supplied to humans for purposes other than tooth whitening, and may be supplied to non-human objects (for example, food).

The UFB liquid generation device 1 includes a mixing section 31, a pressurized liquid generation container 32, a liquid delivery section 2, a storage section 5, a pump 33, a circulation section 6, and a gas supply section 34.

The mixing section 31 is connected to the upper portion of the pressurized liquid generation container 32 . A gas supply unit 34 is connected to the mixing unit 31 . The liquid delivery section 2 is connected to the lower portion of the pressurized liquid generation container 32 . Also, the liquid delivery unit 2 is connected to the storage tank 51 of the storage unit 5 via the first pipe 52 . A pump 33 is attached to the reservoir 51 . The pump 33 is connected to the mixing section 31 via the second pipe 61 of the circulation section 6 . A reservoir 51 of the reservoir 5 stores a liquid for which UFB is to be generated (hereinafter referred to as "target liquid").

The target liquid is a liquid in which additives, which are hydrophilic food additives, are dispersed in water. As the water, for example, tap water, pure water, deionized water (DIW), or the like can be used. Hydrophilic food additives are those that are approved for use as food additives safe for the human body by the Ministry of Health, Labor and Welfare and have hydrophilic properties. A hydrophilic food additive, for example, has a hydrophilic group and can be dispersed in water at room temperature or in a state heated above room temperature. The state in which the hydrophilic food additive is dispersed in water also includes the state in which the hydrophilic food additive is dissolved in water. Commercially available hydrophilic food additives are usually marketed with a statement that they are hydrophilic. Hydrophobic food additives are generally difficult to disperse even in water that is heated above room temperature.

The HLB (Hydrophilic-Lipophilic Balance) value of the additive is preferably 9.0 or higher. The HLB value is a value that indicates the degree of affinity for water and oil, and the higher the HLB value, the higher the affinity for water. In the case of food additives, if the HLB value is 9.0 or more, it can be generally said to be a hydrophilic food additive. Also, the HLB value of the additive is preferably 14.0 or less, more preferably 12.0 or less.

For example, polyglycerin fatty acid ester or sucrose fatty acid ester can be used as the additive. A polyglycerin fatty acid ester comprises a hydrophilic group, polyglycerin, and a hydrophobic group, a fatty acid. A sucrose fatty acid ester comprises sucrose, which is a hydrophilic group, and fatty acid, which is a hydrophobic group. Examples of polyglycerin fatty acid esters that can be used include hexaglycerin monostearate, hexaglycerin monomyristate, decaglycerin monostearate, decaglycerin monomyristate, and the like.

The concentration of the additive in the target liquid (that is, the amount of additive per unit volume of the target liquid) is, for example, 0.1 mg/L (milligram/liter) or more and 10 mg/L or less. Preferably, the concentration of the additive in the target liquid is 1 mg/L or more and 10 mg/L or less.

Next, the flow of UFB liquid generation by the UFB liquid generation device 1 will be described with reference to FIG. Details of each configuration of the UFB liquid generation device 1 will be described later. First, by adding the above additive to water and dispersing it, a target liquid in which UFB is to be generated is generated (step S11). The target liquid is stored in the storage tank 51 of the UFB liquid generator 1 . The target liquid may be generated outside the storage tank 51 and supplied to the storage tank 51 , and by adding an additive to water previously stored in the storage tank 51 , may be generated.

Subsequently, the target liquid stored in the storage tank 51 is pressure-fed to the mixing section 31 via the second pipe 61 by the pump 33 . Further, gas (for example, air) is supplied to the mixing unit 31 by the gas supply unit 34 . The gas supply unit 34 is, for example, a compressor that pressure-feeds air pressurized to a pressure higher than the atmospheric pressure to the mixing unit 31 . In the mixing unit 31, the target liquid supplied under pressure from the pump 33 and the gas supplied under pressure from the gas supply unit 34 are mixed to generate a mixed fluid (step S12). ).

The mixed fluid generated by the mixing section 31 is ejected (that is, supplied) into the pressurized liquid generation container 32 . The inside of the pressurized liquid generation container 32 is a pressurized environment having a pressure higher than the atmospheric pressure. In the pressurized liquid generation container 32, the gas in the mixed fluid is pressurized and dissolved in the target liquid to generate a pressurized liquid (step S13).

The pressurized liquid generated in the pressurized liquid generation container 32 (that is, the mixed fluid obtained by pressurizing and dissolving the gas in the target liquid) is supplied to the liquid delivery section 2 . In the liquid delivery unit 2, the gaseous UFB is generated in the pressurized liquid supplied from the pressurized liquid generation container 32, and the UFB liquid containing the UFB is generated (step S14). The UFB liquid is delivered from the liquid delivery section 2 to the storage tank 51 of the storage section 5 via the first pipe 52 and is temporarily stored in the storage tank 51 . The liquid delivery unit 2 is a generation unit that generates UFB liquid by generating UFB in the target liquid. It should be noted that the generating unit may be construed as including the pressurized liquid generating container 32 as well.

In the UFB liquid generation device 1, the target liquid stored in the storage tank 51 is continuously supplied to the mixing section 31 via the circulation section 6 by the pump 33, and the pressurized liquid generation container 32 and the liquid delivery section are supplied. 2 back into the reservoir 51 . That is, the UFB liquid delivered from the liquid delivery section 2 in step S14 is returned (that is, circulated) to the mixing section 31 by the circulation section 6, and steps S12 to S14 are performed again (steps S15 and S16). In the UFB liquid generator 1, steps S12 to S16 are repeated to increase the concentration of UFB in the UFB liquid and to generate a UFB liquid containing a predetermined concentration of UFB (step S15). Then, the pump 33 is stopped, and the liquid circulation in the UFB liquid generator 1 is stopped. Since UFB can exist in the liquid for a long period of time, it continues to exist in the UFB liquid in the storage tank 51 for a long period of time even after stopping the circulation (that is, after stopping the generation of UFB).

The "concentration" of UFB in the UFB liquid refers to the number of UFB contained per unit volume of the UFB liquid (that is, number concentration). The concentration of UFB in the UFB liquid can be measured, for example, by nanoparticle tracking analysis. In this embodiment, Nanosite "NS500" manufactured by Malvern Panalytical is used as a measuring device to measure the concentration of UFB in the UFB liquid.

The concentration of UFB in the UFB liquid generated by the UFB liquid generator 1 is, for example, 100 million/mL (milliliter) or more when measured immediately after the generation of the UFB liquid. The measurement immediately after the generation of the UFB liquid means measurement at a predetermined timing within 36 hours from when the UFB liquid generation operation is stopped (that is, when the UFB liquid generation device 1 finishes generating the UFB liquid). . The same applies to the following description. The diameter of UFBs contained in the UFB liquid is mainly 200 nm (nanometers) or less. Focusing on the number of UFBs contained in the UFB liquid per unit volume, the number of UFBs with a diameter of 50 nm or more and 200 nm or less is, for example, 80% or more and 100% or less of the total number of UFBs.

The UFB in the UFB liquid remains at a relatively high concentration even after several days have passed since the UFB liquid was produced. For example, the concentration of UFB in the UFB solution 5 days after the above-described measurement immediately after production (that is, on the 6th day when the production end point is defined as day 1) is the concentration of UFB in the UFB solution measured immediately after production. 50% or more of It should be noted that the "concentration of UFB in the UFB liquid 5 days after the measurement immediately after generation" means the measurement of the concentration of UFB immediately after the above generation (i.e., at a predetermined point within 36 hours after the UFB liquid generation operation was stopped). , means the concentration of UFB measured after 5 days (ie 120 hours). During the 5 days, the UFB liquid is stored in a sealed container at room temperature.

In step S15 described above, for example, the relationship between the number of circulations of the UFB liquid in the UFB liquid generator 1 and the concentration of UFB in the UFB liquid is obtained in advance, and the number of circulations reaches a predetermined number (for example, 10 times). When it reaches, it is determined that the concentration of UFB has reached the predetermined concentration. Specifically, for example, the total amount of liquid delivered from the pump 33 obtained based on the flow rate and operating time of the pump 33 is the above-mentioned predetermined number times (for example, 10 times) the total amount of liquid in the UFB liquid generator 1 times), it is determined that the number of circulations has reached a predetermined number, and that the concentration of UFB has reached a predetermined concentration. The total amount of liquid in the UFB liquid generator 1 is the volume of the liquid in the storage tank 51 and the liquid circulating outside the storage tank 51 (that is, the second pipe 61, the mixing section 31, the pressure It is the sum of the volumes of the liquid generation container 32, the liquid delivery section 2, and the liquid in the first pipe 52). In step S15, part of the liquid in the storage tank 51 may be taken out as a sample, and the concentration of UFB in the sample may be measured by the above-described measuring device or the like.

Next, the configuration of the UFB liquid generation device 1 will be described in detail. FIG. 3 is a cross-sectional view showing the mixing section 31 in an enlarged manner. The mixing unit 31 is a mixing nozzle that mixes liquid and gas to generate a mixed fluid, as described above. The mixing section 31 includes a liquid inlet 311 , a gas inlet 319 and a mixed fluid jet 312 . The liquid inlet 311 is connected to the pump 33 via the second pipe 61 (see FIG. 1). The gas inlet 319 is connected to the gas supply section 34 . The mixed fluid jet 312 is connected to the upper end of the pressurized liquid generation container 32 .

The pressurized liquid supplied by the pump 33 (that is, the target liquid) flows from the liquid inlet 311 . A pressurized gas supplied from the gas supply unit 34 flows in from the gas inlet 319 . Mixed fluid 72 (see FIG. 1) in which the liquid flowing in from liquid inlet 311 and the gas flowing in from gas inlet 319 are mixed is ejected from mixed fluid ejection port 312 . Liquid inlet 311, gas inlet 319 and mixed fluid outlet 312 are each substantially circular.

In the mixing section 31, the channel cross section of the nozzle channel 310 from the liquid inlet 311 to the mixed fluid jet 312 and the channel cross section of the gas channel 3191 from the gas inlet 319 to the nozzle channel 310 are also substantially circular. is. A channel cross section means a cross section perpendicular to the central axis of the channel such as the nozzle channel 310 or the gas channel 3191, that is, a cross section perpendicular to the flow of the fluid flowing through the channel. In addition, in the following description, the area of the channel cross section is referred to as "channel area". The nozzle channel 310 has a venturi tubular shape with a smaller channel area in the middle of the channel.

The mixing section 31 includes an introduction section 313, a first taper section 314, a throat section 315, a gas mixing section 316, a second A tapered portion 317 and a lead-out portion 318 are provided. The mixing section 31 also includes a gas inlet section 3192 in which a gas flow path 3191 is provided.

In the introduction part 313, the channel area is substantially constant at each position of the nozzle channel 310 in the central axis J1 direction. In the first tapered portion 314, the flow passage area gradually decreases in the direction in which the liquid flows (that is, toward the downstream). In the throat 315, the flow area is substantially constant. The flow area of the throat 315 is the smallest in the nozzle flow channel 310 . In the nozzle channel 310 , even if the channel area of the throat portion 315 changes slightly, the entire portion having the smallest channel area can be regarded as the throat portion 315 . The gas mixing portion 316 has a substantially constant flow area, which is slightly larger than the flow area of the throat portion 315 . In the second tapered portion 317, the flow passage area gradually increases toward the downstream side. In the lead-out portion 318, the channel area is substantially constant. The flow channel area of the gas flow channel 3191 is also substantially constant, and the gas flow channel 3191 is connected to the gas mixing section 316 of the nozzle flow channel 310 .

In the mixing section 31 , the liquid that has flowed into the nozzle channel 310 from the liquid inlet 311 is accelerated in the throat section 315 to reduce the static pressure. is lower than the pressure in gas inlet 319 . Also, the gas that has flowed into the gas flow path 3191 from the gas inlet 319 is accelerated by the pressure drop and flows into the gas mixing section 316, where it is mixed with the liquid to generate a mixed fluid. The mixed fluid is decelerated at the second taper portion 317 and the lead-out portion 318 to increase the static pressure, and is ejected into the pressurized liquid generation container 32 shown in FIG. be.

In the UFB liquid generation device 1 , the pressurized liquid and gas are ejected from the mixing section 31 into the pressurized liquid generation container 32 . Further, the outlet of the pressurized liquid generation container 32 is throttled by the liquid delivery section 2 . For this reason, the inside of the pressurized liquid generation container 32 is pressurized and is in a state where the pressure is higher than the atmospheric pressure (hereinafter referred to as "pressurized environment"). In other words, the liquid delivery section 2 has a function of making the inside of the pressurized liquid generation container 32 a pressurized environment. In the pressurized liquid generation container 32, as described above, while the mixed fluid 72 ejected from the mixing section 31 flows under the pressurized environment, the gas is pressurized and dissolved in the liquid to generate the pressurized liquid. .

In the example shown in FIG. 1, the pressurized liquid generating container 32 includes a first channel 321, a second channel 322, a third channel 323, a fourth channel 324, and a 5 channel 325 . In the following description, the first flow path 321, the second flow path 322, the third flow path 323, the fourth flow path 324 and the fifth flow path 325 are collectively referred to as "flow paths 321 to 325". The channels 321 to 325 are pipelines extending in the horizontal direction, and cross sections perpendicular to the longitudinal direction of the channels 321 to 325 are substantially rectangular.

The mixing section 31 described above is attached to the upstream end of the first flow path 321 (that is, the left end in FIG. 1), and the mixed fluid 72 ejected from the mixing section 31 is , in a pressurized environment towards the right in FIG. In the example shown in FIG. 1 , the mixed fluid 72 is ejected from the mixing section 31 above the liquid surface of the mixed fluid 72 in the first channel 321 . The mixed fluid 72 immediately after ejected from the mixing section 31 collides directly with the liquid surface before colliding with the wall surface on the downstream side of the first flow path 321 (that is, the wall surface on the right side in FIG. 1).

In the pressurized liquid generation container 32, part or the whole of the mixed fluid ejection port 312 (see FIG. 3) of the mixing section 31 is positioned below the liquid level of the mixed fluid 72 in the first flow path 321. good too. As a result, in the first channel 321 , the mixed fluid 72 immediately after being ejected from the mixing section 31 directly collides with the mixed fluid 72 flowing in the first channel 321 , as described above.

A substantially circular opening 321 a is provided on the lower surface of the downstream end of the first flow path 321 , and the mixed fluid 72 flowing through the first flow path 321 flows through the first flow path 321 located below the first flow path 321 . It drops into the second channel 322 through the opening 321a. In the second channel 322, the mixed fluid 72 dropped from the first channel 321 flows from the right side to the left side in FIG. Through the provided substantially circular opening 322a, the liquid drops into the third flow path 323 positioned below the second flow path 322 . In the third channel 323, the mixed fluid 72 dropped from the second channel 322 flows from the left side to the right side in FIG. Through the provided substantially circular opening 323 a , the liquid drops into the fourth channel 324 positioned below the third channel 323 . As shown in FIG. 1, in the first flow path 321 to the fourth flow path 324, the mixed fluid 72 is divided into a liquid layer containing air bubbles and a gas layer positioned above the liquid layer.

In the fourth flow path 324, the mixed fluid 72 dropped from the third flow path 323 flows from the right side to the left side in FIG. It flows into (that is, falls into) the fifth channel 325 positioned below the fourth channel 324 through the provided substantially circular opening 324a. In the fifth flow path 325, unlike the first flow path 321 to the fourth flow path 324, there is no gas layer. A few bubbles are present in the vicinity of the upper surface of the . In the fifth flow path 325, the mixed fluid 72 flowing from the fourth flow path 324 flows from the left side to the right side in FIG. 1 under a pressurized environment.

In the pressurized liquid generation container 32, the flow paths 321 to 325 flow down from top to bottom while repeating slowness and speed in stages (that is, the mixture flows while alternating between the horizontal flow and the downward flow). In the fluid 72, the gas is gradually pressurized and dissolved in the liquid. In the fifth channel 325, the concentration of dissolved gas in the liquid is approximately equal to 60% to 90% of the (saturated) solubility of the gas under pressure. Excess gas that is not dissolved in the liquid exists as bubbles of a visible size inside the fifth channel 325 . Since the direction of flow of the mixed fluid 72 in the vertically adjacent channels 321 to 325 is opposite, the size of the pressurized liquid generating container 32 can be reduced. In addition, in the pressurized liquid generation container 32, the number of vertically stacked flow paths may be changed as appropriate.

The pressurized liquid generation container 32 further includes a surplus gas separation section 326 extending upward from the upper surface of the fifth flow path 325 on the downstream side. The excess gas separation section 326 is filled with the mixed fluid 72 . The cross section perpendicular to the vertical direction of the surplus gas separation section 326 is substantially rectangular, and the upper end of the surplus gas separation section 326 is open to the atmosphere via a throttle section 327 for pressure adjustment. Bubbles of the mixed fluid 72 flowing through the fifth channel 325 rise inside the surplus gas separation section 326 and are released into the atmosphere.

In this manner, the excess gas of the mixed fluid 72 is separated along with a portion of the mixed fluid 72 to produce a pressurized liquid substantially free of bubbles of at least readily visible size and a fifth The liquid is supplied to the liquid delivery section 2 directly connected to the downstream end of the channel 325 . In the present embodiment, the pressurized liquid contains approximately twice or more the (saturated) solubility of gas dissolved in the pressurized liquid. The liquid of the mixed fluid 72 flowing through the channels 321 to 325 in the pressurized liquid generation container 32 can also be regarded as the pressurized liquid in the process of being generated.

FIG. 4 is a cross-sectional view showing the liquid delivery part 2 in an enlarged manner. The liquid delivery unit 2 is a UFB generation nozzle that generates UFB in the liquid (that is, the pressurized liquid) flowing through the internal nozzle channel 20 . In the example shown in FIG. 4, the liquid delivery section 2 is a multistage nozzle in which three nozzles 28 are connected in series. The number of stages of the nozzles 28 of the liquid delivery section 2 may be one or plural. The liquid delivery section 2 includes a liquid inlet 21 and a liquid delivery port 22 . Pressurized liquid flows from the fifth channel 325 (see FIG. 1) of the pressurized liquid generation container 32 through the liquid inlet 21 . The liquid delivery port 22 is connected through a first pipe 52 to the reservoir 51 (see FIG. 1) of the reservoir 5 . The liquid inlet 21 and the liquid delivery port 22 are each substantially circular, and the channel cross-section of the nozzle channel 20 from the liquid inlet 21 to the liquid delivery port 22 is also approximately circular.

The liquid delivery portion 2 includes three sets of tapered portions 24 and a throat portion 25 that are successively arranged in order from the liquid inlet 21 toward the liquid delivery port 22 (that is, from upstream to downstream of the nozzle channel 20). and an enlarged portion 26 . In the tapered portion 24, the channel area gradually decreases in the direction in which the pressurized liquid flows (that is, from upstream to downstream of the nozzle channel 20). The inner surface of the tapered portion 24 is part of a substantially conical surface centered on the central axis J2 of the nozzle flow path 20 . In a cross section including the central axis J2, the angle formed by the inner surface of the tapered portion 24 is preferably 10° or more and 90° or less.

The throat portion 25 connects to the downstream end of the tapered portion 24 and connects the tapered portion 24 and the enlarged portion 26 . The inner surface of the throat portion 25 is a substantially cylindrical surface, and the flow passage area of the throat portion 25 is substantially constant. The diameter of the channel cross section in the throat portion 25 is the smallest in the nozzle channel 20 , and the channel area of the throat portion 25 is the smallest in the nozzle channel 20 . The length of the throat portion 25 is preferably 1.1 to 10 times the diameter of the throat portion 25, more preferably 1.5 to 2 times. In the nozzle channel 20 , even if the channel area of the throat portion 25 changes slightly, the entire portion with the smallest channel area can be regarded as the throat portion 25 .

The enlarged portion 26 is connected to a spout 29 that is the downstream end of the throat portion 25 . The enlarged portion 26 connects the throat portion 25 on the upstream side and the tapered portion 24 on the downstream side. The inner surface of the enlarged portion 26 is a substantially cylindrical surface, and the flow area of the enlarged portion 26 is substantially constant. The diameter of enlarged portion 26 is greater than the diameter of throat portion 25 . At the enlarged portion 26, the flow passage area is rapidly enlarged as compared with the throat portion 25. As shown in FIG. In a cross section including the central axis J2, the angle between the substantially annular surface 27 between the downstream end of the throat portion 25 and the upstream end of the enlarged portion 26 and the central axis J2 is about 90°. In other words, the surface 27 is substantially perpendicular to the central axis J2. The angle is, for example, 45° or more and 90° or less.

In the liquid delivery portion 2, the pressurized liquid that has flowed into the nozzle flow path 20 from the liquid inlet 21 is gradually accelerated in the tapered portion 24 and flows to the throat portion 25, whereupon it flows into the throat portion 25, and the jet port 29, which is the downstream end of the throat portion 25, flows. , to the enlarged portion 26 as a jet. The flow velocity of the pressurized liquid in the throat 25 is preferably 10 m to 30 m/s. In the throat portion 25, the static pressure of the pressurized liquid decreases, so the gas in the pressurized liquid becomes supersaturated and precipitates in the liquid as UFB. Precipitation of UFB also occurs while the pressurized liquid passes through the enlarged portion 26 . In the liquid delivery part 2, the pressurized liquid sequentially passes through the three sets of taper part 24, throat part 25 and enlarged part 26, thereby generating a UFB liquid containing high-concentration UFB, which is supplied to the first pipe shown in FIG. 52 to reservoir 51 .

Next, with reference to Table 1, the relationship between the type of additive used to generate the target liquid and the concentration of UFB in the UFB liquid generated by the UFB liquid generator 1 will be described. In Examples 1 to 4, the type of additive added to water during the generation of the subject liquid was changed. In Comparative Example 1, UFB was generated from water in the UFB liquid generator 1 without using an additive.

In Example 1, tap water was used as water, and hexaglycerin monostearate was used as an additive to generate the target liquid. The concentration of the additive in the subject liquid is 1 mg/L. The HLB value of the additive is 9.0. The number of carbon atoms (ie the number of C atoms) in the hydrophilic group of the additive is 18 and the number of carbon atoms in the hydrophobic group of the additive is 18. In the UFB liquid generator 1, the UFB liquid was generated with the number of times of circulation set to 10 times.

The concentration of UFB in the UFB liquid was determined using the above-mentioned measuring device. Specifically, first, a predetermined amount of UFB liquid was taken out from the storage tank 51, and the concentration of nanoparticles (that is, fine particles having a particle size of less than 1 μm) in the UFB liquid was measured by the measuring device. Since the measurement results may contain minute foreign substances other than UFB, after forcibly erasing UFB by irradiating the UFB liquid with ultrasonic waves, ultrasonic defoaming is performed by the measuring device. The concentration of nanoparticles in the UFB liquid after being soaked was measured. Then, by subtracting the measurement result after ultrasonic defoaming from the measurement result before ultrasonic defoaming, the concentration of UFB present in the UFB liquid (that is, ultrasonically defoamed) was obtained.

In Example 1, the concentration of UFB in the UFB liquid measured immediately after generation (that is, within 36 hours after the end of generation of the UFB liquid) (hereinafter also referred to as “UFB concentration immediately after generation”) was 1.3 billion/mL. A UFB liquid containing a high concentration of UFB was produced. In addition, the concentration of UFB in the UFB liquid 5 days after the measurement immediately after the production (hereinafter also referred to as "UFB concentration after 5 days") was 1.2 billion/mL. The value obtained by dividing the UFB concentration after 5 days by the UFB concentration immediately after production (hereinafter also referred to as "UFB residual rate") was as high as about 90%, and a UFB liquid with high long-term UFB stability was obtained.

Example 2 is the same as Example 1, except that hexaglycerin monomyristate was used as an additive. The HLB value of the additive is 11.0. The number of carbon atoms in the hydrophilic group of the additive is 18, and the number of carbon atoms in the hydrophobic group of the additive is 14. The UFB concentration immediately after production was 500 million/mL, and a UFB liquid containing a high concentration of UFB was produced. Moreover, the UFB concentration after 5 days was 400 million cells/mL. The UFB residual rate was as high as about 80%, and a UFB liquid with high long-term UFB stability was obtained.

Example 3 is the same as Example 1, except that decaglycerin monostearate was used as an additive. The HLB value of the additive is 12.0. The number of carbon atoms in the hydrophilic group of the additive is 30, and the number of carbon atoms in the hydrophobic group of the additive is 18. The UFB concentration immediately after production was 900 million/mL, and a UFB liquid containing a high concentration of UFB was produced. Moreover, the UFB concentration after 5 days was 900 million cells/mL. The UFB residual rate was as high as about 100%, and a UFB liquid with high long-term UFB stability was obtained.

Example 4 is the same as Example 1, except that decaglycerin monomyristate was used as an additive. The HLB value of the additive is 14.0. The number of carbon atoms in the hydrophilic group of the additive is 30, and the number of carbon atoms in the hydrophobic group of the additive is 14. The UFB concentration immediately after production was 200 million/mL, and a UFB liquid containing a high concentration of UFB was produced. Moreover, the UFB concentration after 5 days was 100 million cells/mL. The UFB residual rate was as high as about 50%, and a UFB liquid with high long-term UFB stability was obtained.

Comparative Example 1 is the same as Example 1, except that the UFB liquid was produced only from water without using additives as described above. The UFB concentration immediately after production was 100 million/mL, and a UFB liquid containing a relatively high concentration of UFB was produced. On the other hand, the UFB concentration after 5 days was about 30 million/mL. The UFB residual rate was as low as about 30%, and the long-term stability of UFB was low.

In Table 1, Example 4 in which the HLB value of the additive is 14.0, and Examples 1 to 3 in which the HLB value of the additive is 12.0 or less (HLB value = 9.0 to 12.0) , the UFB residual rate is about 50% in Example 4, while the UFB residual rate is 80% to 100% in Examples 1 to 3, which is higher than that in Example 4. From this, it can be said that the HLB value of the additive is more preferably smaller than 14.0, and more preferably 12.0 or less.

In Table 1, when comparing Example 1 and Example 2 in which the number of carbon atoms in the hydrophilic group of the additive is the same, Example 1 in which the number of carbon atoms in the hydrophobic group of the additive is 18 has 14 carbon atoms in the hydrophobic group. The UFB concentration immediately after production and the UFB residual rate were higher than in Example 2. In addition, when comparing Example 3 and Example 4 in which the number of carbon atoms in the hydrophilic group of the additive is the same, Example 3 in which the number of carbon atoms in the hydrophobic group of the additive is 18 has 14 carbon atoms in the hydrophobic group. Compared to Example 4, the UFB concentration immediately after production and the UFB residual rate were higher. From this, it can be said that the number of carbon atoms in the hydrophobic group of the additive is more preferably greater than 14, and more preferably 18 or more.

Next, with reference to Table 2, the relationship between the additive concentration in the target liquid and the UFB concentration in the UFB liquid generated by the UFB liquid generation device 1 will be described. Example 1 is as described above, and in Examples 5 and 6, the amount of additive added to water when the target liquid is generated (ie, the concentration of the additive in the target liquid) was changed.

Example 5 is the same as Example 1, except that the concentration of the additive (hexaglycerol monostearate) in the subject liquid was 0.1 mg/L. In Example 5, the UFB concentration immediately after production was 100 million/mL, and a UFB liquid containing a relatively high concentration of UFB was produced.

Example 6 is the same as Example 1, except that the concentration of the additive (hexaglycerol monostearate) in the subject liquid was 10 mg/L. In Example 6, the UFB concentration immediately after production was 1.4 billion/mL, and a UFB liquid containing a high concentration of UFB was produced.

In Example 6, a phenomenon was observed in which the target liquid foamed during the generation of UFB. From the viewpoint of suppressing the foaming, the concentration of the additive in the target liquid is preferably 10 mg/L or less. Moreover, from the viewpoint of achieving a UFB concentration of 100 million/mL or more immediately after production, the concentration of the additive in the subject liquid is preferably 0.1 mg/L or more. Furthermore, from the viewpoint of increasing the UFB concentration immediately after production, the concentration of the additive in the subject liquid is more preferably 1 mg/L or more.

In Examples 1 to 6 described above, polyglycerin fatty acid ester was used as an additive, but when sucrose fatty acid ester was used as an additive, it contained a high concentration of UFB in substantially the same manner, and the long-term stability of UFB A UFB liquid with high resistance was obtained.

As described above, the UFB liquid generation method includes a step of dispersing an additive, which is a hydrophilic food additive, in water to generate a target liquid (step S11); and generating a UFB liquid containing UFB by mixing and generating the gaseous UFB in the target liquid (steps S12 to S14). The additive is polyglycerin fatty acid ester or sucrose fatty acid ester. This makes it possible to produce a UFB liquid that is safe to the human body, contains a high concentration of UFB, and has high long-term stability of UFB.

As described above, the concentration of UFB in the UFB liquid measured immediately after generation is 100 million/mL or more, and the concentration of UFB in the UFB liquid 5 days after the measurement immediately after generation is the UFB measured immediately after generation. It is preferably 50% or more of the concentration of UFB in the liquid. This makes it possible to provide a UFB liquid with higher long-term UFB stability.

As described above, the HLB value of the additive is preferably 9.0 or higher. This makes it easier to disperse the additive in water. As a result, the UFB liquid described above can be easily produced.

As described above, the additive concentration in the target liquid is preferably 10 mg/L or less. As a result, a UFB liquid containing a high concentration of UFB and having high long-term stability of UFB can be produced while reducing the amount of additive used.

In the UFB liquid generation method, preferably, in steps S12 to S14, the gas is pressurized and dissolved in the target liquid to generate a pressurized liquid, and the UFB is precipitated from the pressurized liquid to generate the UFB liquid. This makes it possible to suitably produce a UFB liquid containing UFB at a high concentration. More preferably, steps S12 to S14 are performed again for the UFB liquid generated in steps S12 to S14. This can increase the concentration of UFB in the UFB liquid.

As described above, the UFB liquid is preferably supplied into the oral cavity during tooth whitening. Since the UFB liquid is safe for the human body, it can be used for tooth whitening. In addition, since the UFB liquid contains UFB at a high concentration, it is possible to improve the teeth whitening effect. Furthermore, since the UFB liquid has high long-term stability, it is possible to generate and store in advance the amount of UFB liquid necessary for whitening a plurality of subjects. Therefore, whitening can be performed more efficiently than in the case where the long-term stability of UFB is low and UFB liquid needs to be generated every time one subject is whitened.

The UFB liquid generation device 1 described above includes a mixing section 31 and a generation section (that is, the liquid delivery section 2). The mixing unit 31 mixes the gas and the pressurized target liquid to generate a mixed fluid. The generation unit generates a UFB liquid containing UFB by generating gaseous UFB in the target liquid in the mixed fluid. The target liquid is a liquid in which an additive, which is a hydrophilic food additive, is dispersed in water. The additive is polyglycerin fatty acid ester or sucrose fatty acid ester. Thereby, as described above, it is possible to produce a UFB liquid that is safe to the human body, contains a high concentration of UFB, and has high long-term stability of UFB.

In addition, the UFB liquid generation method includes a step of dispersing an additive, which is a hydrophilic food additive, in water to generate a target liquid (step S11), mixing the gas and the pressurized target liquid, and and generating a UFB liquid containing UFB by generating the gaseous UFB in the liquid (steps S12 to S14). The concentration of UFB in the UFB liquid measured immediately after generation is 100 million/mL or more, and the concentration of UFB in the UFB liquid 5 days after the measurement immediately after generation is equal to the concentration of UFB in the UFB liquid measured immediately after generation 50% or more of This makes it possible to provide a UFB liquid that is safe to the human body, contains a high concentration of UFB, and has high long-term stability of UFB.

In addition, the UFB liquid generation device 1 described above includes a mixing section 31 and a generation section (that is, the liquid delivery section 2). The mixing unit 31 mixes the gas and the pressurized target liquid to generate a mixed fluid. The generation unit generates a UFB liquid containing UFB by generating gaseous UFB in the target liquid in the mixed fluid. The target liquid is a liquid in which an additive, which is a hydrophilic food additive, is dispersed in water. The concentration of UFB in the UFB liquid measured immediately after generation is 100 million/mL or more, and the concentration of UFB in the UFB liquid 5 days after the measurement immediately after generation is equal to the concentration of UFB in the UFB liquid measured immediately after generation 50% or more of As a result, it is possible to provide a UFB liquid that is safe to the human body, contains a high concentration of UFB, and has high long-term UFB stability.

Various modifications are possible in the UFB liquid generation method and the UFB liquid generation device 1 described above.

For example, in the UFB liquid generation device 1, the gas supplied to the mixing section 31 by the gas supply section 34 may be various gases other than air (for example, nitrogen gas). Gas supply 34 is not limited to a compressor and may be modified in various ways. For example, the gas supply unit 34 may be a gas cylinder filled with nitrogen gas or the like having a pressure higher than atmospheric pressure.

In the UFB liquid generation device 1, when the required amount of gas such as air is sucked from the gas inlet 319 by the negative pressure generated by the liquid flowing through the nozzle channel 310 of the mixing section 31, the gas supply section 34 may be omitted. good. In this case, the gas mixed with the pressurized target liquid in the mixing section 31 has substantially the same pressure as the atmospheric pressure, instead of being in a pressurized state.

In the UFB liquid generation device 1, for example, water and additives may be supplied to the mixing section 31 or the pressurized liquid generation container 32 through separate paths and mixed. Further, the structure and shape of the pressurized liquid generation container 32 may be changed variously.

The structure of the liquid delivery unit 2 is not limited to the one described above, and may be modified in various ways. For example, the UFB generation nozzle of the liquid delivery part 2 may be provided with two sets, or four or more sets of the taper part 24, the throat part 25 and the enlarged part 26 that are continuous from upstream to downstream. Alternatively, the UFB generation nozzle may have only one set of tapered portion 24, throat portion 25 and enlarged portion 26 that are continuous from upstream to downstream. The liquid delivery part 2 does not necessarily have the taper part 24, the throat part 25 and the enlarged part 26, and may be a UFB generation nozzle with other structure.

The liquid delivery unit 2 does not necessarily have to be a UFB generation nozzle that generates UFB in the pressurized liquid by ejecting the pressurized liquid, and may generate UFB by various known generation methods. For example, the UFB may be generated by applying ultrasonic waves in the liquid delivery unit 2 to the mixed fluid generated by the mixing unit 31, or by applying shear force by the internal structure of the liquid delivery unit 2. . In this case, the pressurized liquid generation container 32 may be omitted from the UFB liquid generation device 1 .

In the UFB liquid generator 1, for example, the circulation of the UFB liquid via the circulation unit 6 may not be performed. In this case, the circulation unit 6 may be omitted from the UFB liquid generator 1 .

The additive used to generate the target liquid may be a hydrophilic food additive other than polyglycerin fatty acid ester and sucrose fatty acid ester. Also, the HLB value of the additive may be less than 9.0. The concentration of the additive in the subject liquid may be higher than 10 mg/L.

The concentration of UFBs in the UFB liquid immediately after production may be less than 100 million/mL. Also, the UFB survival rate described above may be less than 50%.

The configurations in the above embodiment and each modification may be combined as appropriate as long as they do not contradict each other.

Although the invention has been described in detail, the above description is illustrative and not limiting. Accordingly, many modifications and variations are possible without departing from the scope of the present invention.

1 UFB liquid generation device 2 liquid delivery unit 31 mixing unit 32 pressurized liquid generation container S11 to S16 steps

Claims

A method for generating an ultra-fine bubble liquid,
a) dispersing an additive, which is a hydrophilic food additive, in water to generate a target liquid;
b) mixing a gas with the pressurized target liquid to generate ultra-fine bubbles of the gas in the target liquid to generate an ultra-fine bubble liquid containing the ultra-fine bubbles;
with
Said additive is polyglycerol fatty acid ester or sucrose fatty acid ester.
The ultra-fine bubble liquid generation method according to claim 1,
The concentration of the ultra-fine bubbles in the ultra-fine bubble liquid measured immediately after generation is 100 million/mL or more,
The concentration of the ultra-fine bubbles in the ultra-fine bubble liquid 5 days after the measurement immediately after the generation is 50% or more of the concentration of the ultra-fine bubbles in the ultra-fine bubble liquid measured immediately after the generation.
The method for generating an ultrafine bubble liquid according to claim 1 or 2,
The HLB value of the additive is 9.0 or more.
The method for generating an ultra-fine bubble liquid according to any one of claims 1 to 3,
The concentration of the additive in the target liquid is 10 mg/L or less.
A method for generating an ultra-fine bubble liquid,
a) dispersing an additive, which is a hydrophilic food additive, in water to generate a target liquid;
b) mixing a gas with the pressurized target liquid to generate ultra-fine bubbles of the gas in the target liquid to generate an ultra-fine bubble liquid containing the ultra-fine bubbles;
with
The concentration of the ultra-fine bubbles in the ultra-fine bubble liquid measured immediately after generation is 100 million/mL or more,
The concentration of the ultra-fine bubbles in the ultra-fine bubble liquid 5 days after the measurement immediately after the generation is 50% or more of the concentration of the ultra-fine bubbles in the ultra-fine bubble liquid measured immediately after the generation.
The method for generating an ultra-fine bubble liquid according to any one of claims 1 to 5,
In the step b), the gas is pressurized and dissolved in the target liquid to generate a pressurized liquid, and the ultrafine bubbles are precipitated from the pressurized liquid to generate the ultrafine bubble liquid.
The ultra-fine bubble liquid generation method according to any one of claims 1 to 6,
The ultra-fine bubble liquid is supplied into the oral cavity during tooth whitening.
An ultra-fine bubble liquid generator,
a mixing unit that mixes the gas and the pressurized target liquid to generate a mixed fluid;
a generation unit that generates an ultra-fine bubble liquid containing the ultra-fine bubbles by generating ultra-fine bubbles of the gas in the target liquid in the mixed fluid;
with
The target liquid is a liquid in which an additive, which is a hydrophilic food additive, is dispersed in water,
Said additive is polyglycerol fatty acid ester or sucrose fatty acid ester.
An ultra-fine bubble liquid generator,
a mixing unit that mixes the gas and the pressurized target liquid to generate a mixed fluid;
a generation unit that generates an ultra-fine bubble liquid containing the ultra-fine bubbles by generating ultra-fine bubbles of the gas in the target liquid in the mixed fluid;
with
The target liquid is a liquid in which an additive, which is a hydrophilic food additive, is dispersed in water,
The concentration of the ultra-fine bubbles in the ultra-fine bubble liquid measured immediately after generation is 100 million/mL or more,
The concentration of the ultra-fine bubbles in the ultra-fine bubble liquid 5 days after the measurement immediately after the generation is 50% or more of the concentration of the ultra-fine bubbles in the ultra-fine bubble liquid measured immediately after the generation.