Method and device for preparing pure emulsion

Abstract

The invention provides a method for preparing pure emulsion, which comprises the following steps of: adding water with the depth of more than 4mm into a container, paving a layer of oil with the thickness of not more than 1mm on the water surface, vertically placing an ultrasonic probe with the diameter of 5-100mm above the liquid level of an oil layer without contacting with the liquid level of the oil layer, setting the ultrasonic frequency to be 20kHz-200kHz, and controlling the ultrasonic frequency to be 20kHz-200kHz; the power of the ultrasonic transducer is adjusted to be 10-2000 W, the distance between the ultrasonic probe and the liquid level is adjusted to be n lambda / 2 + / -0.1 mm, n is a positive integer, lambda is the wavelength of sound waves, after ultrasonic starting, emulsification is started, and emulsion is obtained 10-60 s later. The invention further discloses a device for preparing the pure emulsion. The non-contact ultrasonic emulsification technology is adopted, the long-life emulsion can be obtained under the condition that no surfactant is used, the purity of the emulsion is further improved, and the emulsion only containing the needed dispersion phase and continuous phase can be obtained when the device is used in an ultra-clean room.

Description

Technical Field

[0001] The invention belongs to the technical field of ultrasonic emulsification, and in particular relates to a method and a device for preparing pure emulsion. Background Art

[0002] Currently, the common methods for preparing emulsions are mechanical shearing and ultrasonic cavitation. However, both methods require the addition of emulsifiers (e.g., surfactants, etc.) to the emulsion during the preparation process, which greatly affects the purity of the emulsion. In particular, when preparing an emulsion containing only a single solute (dispersed phase), the purity of the emulsion is poor.

[0003] At the same time, the devices used in the current common emulsion preparation process require that the stirring parts come into contact with the emulsion during mechanical stirring, or that the ultrasonic probe comes into contact with the emulsion to varying degrees during ultrasonic cavitation. The contact device will not only cause the emulsion to be impure, but also have varying degrees of impact on the preparation device itself when preparing corrosive emulsions, causing corrosion and aging of the preparation device. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method and device for preparing a pure emulsion in view of the deficiencies of the above-mentioned prior art. The method provides a non-contact technology for preparing the emulsion, forming a surface electric field between dispersed phase droplets. The dispersed phase droplets repel each other through the surface electric field to avoid merging. Without adding an emulsifier, the pure emulsion prepared by the present invention can exist for an extremely long time, and the emulsion life is more than four weeks.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a pure emulsion, which method comprises: adding water with a depth greater than 4 mm into a container, and spreading a layer of oil with a thickness not exceeding 1 mm on the water surface, and then vertically placing an ultrasonic probe with a diameter of 5-100 mm above the liquid surface of the oil layer without contacting the liquid surface of the oil layer, setting the frequency of ultrasound to 20kHz-200kHz, adjusting the power of the ultrasonic transducer to 10-2000W, adjusting the distance between the ultrasonic probe and the liquid surface to nλ / 2±0.1 mm, wherein n is a positive integer, λ is the wavelength of the sound wave, and after ultrasound is started, emulsification begins, and an emulsion is obtained after 10-60s; the density of the oil is less than that of water, and the viscosity is 3-200mpa·s.

[0006] Preferably, the maximum distance between the ultrasonic probe and the liquid surface does not exceed 50.1 mm.

[0007] Preferably, the oil is one or more of silicone oil, coconut oil, soybean oil, rapeseed oil, castor oil and olive oil.

[0008] Preferably, the frequency of ultrasound is set to 20kHz-40kHz, and the power of the ultrasonic transducer is adjusted to 100-500W.

[0009] The inventor also discloses a device for preparing pure emulsion, comprising a box body and an ultrasonic regulating device installed in the box body, a container for containing water and oil is arranged below the ultrasonic regulating device, the box body is composed of an upper box body and a lower box body, an ultrasonic generating device is installed in the ultrasonic regulating device, and the ultrasonic generating device includes an ultrasonic transducer and an ultrasonic probe.

[0010] Preferably, the ultrasonic adjustment device includes a middle partition and a support plate, the middle partition is fixed between the upper box body and the lower box body, an ultrasonic generating device is clamped and fixed on the support plate, the support plate is fixed above the middle partition by a support plate fixing device, and two screws are also passed between the middle partition and the support plate, both screws are driven by a motor, the screws are threadedly matched with the support plate, and the motor controls the rotation of the screw, thereby controlling the support plate to move up and down along the screw.

[0011] Preferably, the support plate fixing device includes four support rods installed between the middle partition and the support plate, the bottom ends of the support rods are fixedly connected to the middle partition via a fixing block, the fixing block is fixed to the middle partition via a screw, the top ends of the support rods are slidably connected to the support plate via a sliding block, the sliding block is slidably arranged on one side of the top end of the support rod, and the sliding block is fixed to the support plate via a screw.

[0012] Preferably, the upper box body includes an upper box body shell, in which a power supply box, a signal generating box, a temperature control system and a motor power supply box are installed. The power supply box is connected to an ultrasonic power supply that provides variable voltage for the ultrasonic generating device. The signal generating box is installed with a control circuit board for controlling the ultrasonic frequency. The temperature control system includes a cooling fan, a fan controller, and a temperature sensor. The temperature sensor is used to detect the temperature in the box body and then transmit it to the fan controller. Once it is detected that the temperature exceeds the threshold, the fan controller controls the cooling fan to start, increase the flow of air in the box body, and cool it down. A motor power supply is installed in the motor power supply box, and the motor power supply powers the motor. A motor controller for controlling the motor is installed at the bottom of the middle partition, and the controller is electrically connected to the motor power supply and the motor.

[0013] Preferably, a display control panel is also installed on the upper box body, and the display control panel is electrically connected to the ultrasonic generating device, the ultrasonic power supply, the control circuit board, the motor power supply, the motor controller, and the fan controller.

[0014] Preferably, the lower box body includes a lower box body shell and a box door installed on the lower box body shell, a coarse adjustment base is installed on the inner bottom surface of the lower box body, a clamp is installed on the coarse adjustment base, the clamp is used to clamp and fix a container for containing water and oil, and a dynamic light scattering instrument is also installed on the inner wall of the lower box body shell.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] 1. Compared with the emulsion prepared by the conventional ultrasonic cavitation and mechanical shearing technology, the ultrasonic probe used in the process of preparing the emulsion of the present invention does not directly contact the emulsion and will not pollute the emulsion. In addition, the present invention provides an ultrasonic emulsion preparation technology, which can obtain a long-life emulsion without using a surfactant, further improving the purity of the emulsion. By using the device of the present invention in a clean room, an emulsion containing only the desired dispersed phase and continuous phase can be obtained, which greatly improves the purity of the emulsion.

[0017] 2. The present invention specifically uses silicone oil, coconut oil, soybean oil and other oils with a viscosity coefficient of less than 100 mm 2 / s oil, with water as the emulsion base, it was found that when the emulsion was prepared using the method of the present invention, the diameter of the dispersed phase droplets ranged from 10-100 mm. Under the condition of adjusting the ultrasonic power, a uniform dispersed phase diameter in the range of 10 nanometers could be obtained. The dispersed phase diameter of the finished emulsion had a narrow dispersion range, which further promoted the stability of the pure emulsion.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 These are pictures of the Rayleigh-Taylor instability process. (a) is a picture of the sound-induced Rayleigh-Taylor instability phenomenon; (b) is a picture of a droplet escaping from the oil phase and entering the water phase.

[0020] Figure 2 Microscopic image of the emulsion prepared in Example 1 of the present invention.

[0021] Figure 3 Microscopic image of the emulsion prepared in Example 1 of the present invention.

[0022] Figure 4 Microscopic images of emulsions disclosed in the prior art.

[0023] Figure 5 It is a schematic diagram of the structure of the device for preparing pure emulsion of the present invention.

[0024] Figure 6 yes Figure 5 AA cross-section diagram.

[0025] Figure 7 The ultrasonic regulating device of the present invention.

[0026] Figure 8 yes Figure 7 AA section view of the .

[0027] Fig. 9 It is a schematic diagram of the outer structure of the upper box body of the present invention.

[0028] Fig.10 It is a schematic diagram of the inner structure of the upper box body of the present invention.

[0029] Description of reference numerals:

[0030] 1—upper box; 1.1—upper box shell; 1.2—display control panel; 1.3—power box; 1.4—signal generating box; 1.5—temperature control system; 1.6—motor power box; 2—ultrasonic adjustment device; 2.1—ultrasonic generating device; 2.2—support plate; 2.3—middle partition; 2.4—support plate fixing device; 2.5—screw; 2.6—motor; 3—lower box; 3.1—clamp; 3.2—dynamic light scattering instrument; 3.3—coarse adjustment base; 3.4—box door; 3.5—lower box shell. DETAILED DESCRIPTION

[0031] Example 1

[0032] This embodiment discloses a method for preparing a pure emulsion, the method comprising:

[0033] Add water with a depth greater than 4 mm into the container, and spread a layer of oil with a thickness not exceeding 1 mm on the water surface, then place an ultrasonic probe with a diameter of 5-100 mm vertically above the oil layer surface without touching the oil layer surface, set the ultrasonic frequency to 20kHz-200kHz, adjust the power of the ultrasonic transducer to 10-2000W, and adjust the distance between the ultrasonic probe and the liquid surface to nλ / 2±0.1 mm, where n is a positive integer, n=2, and λ is the wavelength of the sound wave. After the ultrasound is started, emulsification begins, and an emulsion is obtained after 10-60s.

[0034] The density of the oil is less than that of water, and the viscosity is 3-200 mPa·s. The oil can be one or more of silicone oil, coconut oil, soybean oil, rapeseed oil, castor oil and olive oil, etc. In the specific implementation, dimethyl silicone oil is used, and the viscosity is 100 mPa·s.

[0035] In the present invention, after the ultrasound is activated, the liquid surface will be disturbed due to the effect of the acoustic radiation force. A It can be calculated according to King's theory:

[0036]

[0037] where ρ 0 is the air density, c is the speed of sound, p is the sound pressure, and v is the vibration speed of the medium particles.

[0038] In this process, when the amplitude of the disturbance of the liquid surface due to acoustic radiation is comparable to the wavelength of the capillary wave on the liquid surface, a nonlinear effect occurs, characterized by the formation of rising and falling plumes. These plumes separate from the original area of ​​the fluid and enter the opposite area, thereby enhancing the transmission between the two layers of liquid, that is, Rayleigh-Taylor instability occurs between the oil layer and the water. The energy required for this process can be derived from the following equation:

[0039]

[0040] Where β is the expansion coefficient, g is the gravity constant, T is the temperature, and ε v is the viscous dissipation rate of the liquid.

[0041] The acoustic radiation force acts as gravity in this process, inducing the Rayleigh-Taylor instability phenomenon, such as Figure 1 (a). Subsequently, the oil droplets formed by this process escape from the oil layer into the water phase, e.g. Figure 1 (b), the size of the produced oil droplets is 0.7 μm-8 μm.

[0042] In the prior art, an ultrasonic probe (ultrasonic probe with a smaller end face) is placed in a vial containing a surfactant, dimethyl silicone oil and water for ultrasonic cavitation to prepare an emulsion, such as Figure 4 As shown in the figure, the size of the emulsion droplets ranges from a dozen microns to more than a hundred microns, the size is uneven, the phase difference is relatively large, and the roundness is not high.

[0043] In this embodiment, when the frequency of ultrasound is set to 20.5kHz and the power of the ultrasonic transducer is set to 100W, the following Figure 2 The microscopic image of the emulsion shown in FIG. 1 is between 10 and 20 μm in size. The frequency of ultrasound was set to 40 kHz and the power of the ultrasonic transducer was set to 100 W to obtain the following Figure 4 Microscopic images of the emulsions shown, with sizes between 0.1-1 μm. Figure 2 and Figure 3 The size of the emulsion droplets is more uniform and has a high roundness, and is basically a standard sphere. Moreover, the emulsion prepared by the present invention can be stable for more than 10 days without adding any stabilizer, while the traditional method can only be stable for a few hours without adding a stabilizer.

[0044] In the emulsion prepared in this embodiment, the ultrasonic probe does not contact the liquid surface, and the obtained emulsion has a higher purity.

[0045] In this embodiment, the frequency of ultrasound can also be set to 20kHz, 30kHz, 40kHz, 100kHz, 150kHz, 200kHz, etc., and the power of the ultrasonic transducer can also be adjusted to 10W, 200W, 500W, 1000W, 2000W, etc., which can be selected according to actual needs. The power of ultrasound is related to the yield of emulsion droplets of the emulsion. The larger the frequency of ultrasound, the smaller the size.

[0046] Example 2

[0047] like Figure 5-9 As shown, this embodiment discloses a device for preparing a pure emulsion, including a box body and an ultrasonic regulating device 2 installed in the box body, a container for holding water with a depth greater than 4 mm and oil with a thickness of no more than 1 mm on the water surface is arranged below the ultrasonic regulating device 2, and the box body is composed of an upper box body 1 and a lower box body 3.

[0048] The ultrasonic adjustment device 2 includes a middle partition 2.3 and a support plate 2.2. The middle partition 2.3 is fixed between the upper box body 1 and the lower box body 3. An ultrasonic generating device 2.1 is clamped and fixed on the support plate 2.2. The support plate 2.2 is fixed above the middle partition 2.3 by a support plate fixing device 2.4. Two screws 2.5 are also passed between the middle partition 2.3 and the support plate 2.2. The screws 2.5 are driven by a motor 2.6. The motor 2.6 is fixed at the bottom of the middle partition 2.3. The screws 2.5 are threadedly matched with the support plate 2.2. After the motor 2.6 is started, the support plate 2.2 is prompted to move up and down along the screws 2.5.

[0049] In this embodiment, the support plate fixing device 2.4 includes four support rods installed between the middle partition 2.3 and the support plate 2.2, the bottom ends of the support rods are fixedly connected to the middle partition 2.3 through fixed blocks, the fixed blocks are fixed to the middle partition 2.3 through screws, the top ends of the support rods are slidably connected to the support plate 2.2 through sliding blocks, the sliding blocks are slidably arranged on one side of the top end of the support rods, and the sliding blocks are fixed to the support plate 2.2 through screws.

[0050] In this embodiment, the ultrasonic generating device 2.1 includes an ultrasonic transducer and an ultrasonic probe.

[0051] In this embodiment, the upper box 1 includes an upper box shell 1.1, and a power box 1.3, a signal generating box 1.4, a temperature control system 1.5 and a motor power box 1.6 are installed in the upper box shell 1.1. The power box 1.3 is connected with an ultrasonic power supply that provides a variable voltage for the ultrasonic generating device 2.1, and the purpose of controlling the ultrasonic power is achieved through different voltages. A control circuit board for controlling the ultrasonic frequency is installed in the signal generating box 1.4. The temperature control system 1.5 includes a cooling fan, a fan controller, and a temperature sensor. The temperature sensor is used to detect the temperature in the box and then transmit it to the fan controller. Once the temperature is detected to exceed the threshold, the fan controller controls the cooling fan to start, increase the flow of air in the box, and cool down. A motor power supply is installed in the motor power box 1.6, and the motor power supply supplies power to the motor 2.6. A motor controller for controlling the motor 2.6 is installed at the bottom of the middle partition 2.3, and the controller is electrically connected to the motor power supply and the motor 2.6.

[0052] In this embodiment, a display control panel 1.2 is also installed on the upper box body, and the display control panel 12 is electrically connected to the ultrasonic generating device 2.1, the ultrasonic power supply, the control circuit board, the motor power supply, the motor controller, and the fan controller.

[0053] In this embodiment, the display control panel 1.2 may specifically be a touch screen control panel.

[0054] In this embodiment, the lower box body 3 includes a lower box body shell 3.5 and a box door 3.4 installed on the lower box body shell 3.5. A coarse adjustment base 3.3 is installed on the inner bottom surface of the lower box body 3. A clamp 3.1 is installed on the coarse adjustment base 3.3. The clamp 3.1 is used to clamp and fix a container for containing water and oil. A dynamic light scattering instrument 3.2 is also installed on the inner wall of the lower box body shell 3.5 for observing the emulsion formation process, especially the size of the emulsion droplets, so as to better control the quality of the emulsion formation.

[0055] The working process of preparing the emulsion using the device in Example 2 is as follows: first place the container on the fixture 3.1, and then place the ultrasonic generating device 2.1 on the support plate 2.2. The ultrasonic probe of the ultrasonic generating device does not contact the liquid surface of the oil layer. The height of the container is adjusted by the coarse adjustment base 3.3, and then the motor controls the rotation of the lead screw 2.5 to adjust the up and down movement of the support plate 2.2, so that the distance between the ultrasonic probe and the liquid surface is adjusted to nλ / 2±0.1 mm, the power of the ultrasonic transducer is set, the ultrasound is started, and emulsification begins. The emulsion is obtained within 1 minute.

[0056] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a pure emulsion, characterized in that: The method comprises the following steps: adding water with a depth greater than 4 mm into a container, and spreading a layer of oil with a thickness not exceeding 1 mm on the water surface; then vertically placing an ultrasonic probe with a diameter of 5-100 mm above the surface of the oil layer without contacting the surface of the oil layer; setting the frequency of the ultrasound to 20 kHz-200 kHz, adjusting the power of the ultrasonic transducer to 10-2000 W, adjusting the distance between the ultrasonic probe and the liquid surface to nλ / 2±0.1 mm, wherein n is a positive integer, and λ is the wavelength of the sound wave; after the ultrasound is started, emulsification begins, and an emulsion is obtained after 10-60 seconds; the density of the oil is less than that of water, and the viscosity is 3-200 mpa·s.

2. The method according to claim 1, characterized in that The maximum distance between the ultrasonic probe and the liquid surface is no more than 50.1 mm.

3. The method according to claim 1, characterized in that The oil is one or more of silicone oil, coconut oil, soybean oil, rapeseed oil, castor oil and olive oil.

4. The method according to claim 1, characterized in that The frequency of ultrasound was set to 20kHz-40kHz, and the power of the ultrasonic transducer was adjusted to 100-500W.

5. A device for preparing a pure emulsion as claimed in any one of claims 1 to 4, characterized in that: It comprises a box body and an ultrasonic regulating device installed in the box body, a container for containing water and oil is arranged below the ultrasonic regulating device, the box body is composed of an upper box body and a lower box body, an ultrasonic generating device is installed in the ultrasonic regulating device, and the ultrasonic generating device comprises an ultrasonic transducer and an ultrasonic probe.

6. The device according to claim 5, characterized in that The ultrasonic adjustment device includes a middle partition and a support plate. The middle partition is fixed between the upper box body and the lower box body. An ultrasonic generating device is clamped and fixed on the support plate. The support plate is fixed above the middle partition by a support plate fixing device. Two screws are also passed between the middle partition and the support plate. The two screws are driven by a motor. The screws are threaded with the support plate. The motor controls the rotation of the screw, thereby controlling the support plate to move up and down along the screw.

7. The device according to claim 6, characterized in that The support plate fixing device includes four support rods installed between the middle partition and the support plate, the bottom ends of the support rods are fixedly connected to the middle partition via a fixing block, the fixing block is fixed to the middle partition via a screw, the top ends of the support rods are slidably connected to the support plate via a sliding block, the sliding block is slidably arranged on one side of the top end of the support rod, and the sliding block is fixed to the support plate via a screw.

8. The device according to claim 5, characterized in that The upper box body includes an upper box body shell, in which a power supply box, a signal generating box, a temperature control system and a motor power supply box are installed. The power supply box is connected to an ultrasonic power supply for providing a variable voltage to an ultrasonic generating device. A control circuit board for controlling the ultrasonic frequency is installed in the signal generating box. The temperature control system includes a cooling fan, a fan controller and a temperature sensor. The temperature sensor is used to detect the temperature in the box body and then transmit it to the fan controller. Once it is detected that the temperature exceeds a threshold, the fan controller controls the cooling fan to start, increases the flow of air in the box body, and cools it down. A motor power supply is installed in the motor power supply box, and the motor power supply supplies power to the motor. A motor controller for controlling the motor is installed at the bottom of the middle partition, and the controller is electrically connected to the motor power supply and the motor.

9. The device according to claim 8, characterized in that A display control panel is also installed on the upper box body, and the display control panel is electrically connected to the ultrasonic generating device, the ultrasonic power supply, the control circuit board, the motor power supply, the motor controller, and the fan controller.

10. The device according to claim 5, characterized in that The lower box body includes a lower box body shell and a box door installed on the lower box body shell. A coarse adjustment base is installed on the inner bottom surface of the lower box body. A clamp is installed on the coarse adjustment base. The clamp is used to clamp and fix a container for accommodating water and oil. A dynamic light scattering instrument is also installed on the inner wall of the lower box body shell.

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