A foaming device, a foaming method and a foaming pressure measurement method

Abstract

The present invention belongs to the technical field of thermally expandable microsphere foaming equipment, and particularly relates to a foaming device, a foaming method and a foaming pressure measurement method. The foaming device includes a hot bath device, a heating chamber, a pressure measurement device and a sealing body. A strip-shaped foaming cavity is formed on the heating device, which can make the expandable microspheres and their derivatives uniformly heated at each part and have the same heating time during the foaming process. Therefore, the foaming particles in the foaming result are uniformly and completely distributed. A method of instant foaming is proposed in the foaming method, which improves the foaming efficiency and further makes the foaming particles in the foaming result uniformly and completely distributed. The pressure measurement method is proposed in combination with the foaming device, which can improve the efficiency of pressure measurement during the foaming process and reduce the cost of the foaming device.

Description

Technical Field

[0001] The invention belongs to the technical field of heat expandable microsphere foaming equipment, and in particular relates to a foaming device, a foaming method and a foaming pressure measuring method. Background Art

[0002] Heat expandable microspheres are known in the prior art and are described in detail in patents US3615972, EP486080, EP566367, EP1067151, ZL201210241564.5, 201210109302.3 and 201280073857.5. Heat expandable microspheres are in the form of dry powder, wet slurry and mixed with other substances. The foaming agent of the heat expandable microspheres is encapsulated in a thermoplastic shell. When the temperature rises, due to the low boiling point of the foaming agent, the foaming agent gasifies, the internal pressure increases, and at the same time, the temperature rises, the shell softens, and under the action of the internal pressure, the microspheres foam, and usually their diameter can increase by 2 to 5 times.

[0003] During the heating and foaming process of the microspheres, as the foaming agent gradually vaporizes, the gas also leaks when the microspheres reach their maximum volume. When the gas leaks too much and the internal pressure generated by the foaming agent is insufficient to support the structure, the microspheres will shrink. In ordinary foaming test tubes, due to uneven heating in various parts of the test tube, more heat is received near the tube wall, while less heat is received in the center, which will cause the parts near the tube wall to foam faster and even reach the shrinkage stage, while the center is heated more slowly and the microspheres have not yet foamed to their maximum volume. This will eventually cause the outer layer to foam faster and the inner layer to foam slower, resulting in uneven foaming. At the same foaming position, the foaming speed and shrinkage time of microspheres of different particle sizes are also inconsistent, which will also lead to uneven foaming. Summary of the invention

[0004] In order to solve the technical problem of uneven foaming of expandable microspheres and their derivatives in the prior art, a foaming device, a foaming method and a foaming pressure measurement method are proposed, which adopt a unique heating and foaming method to avoid the problems of uneven foaming and microsphere adhesion.

[0005] In order to achieve the above technical effects, the specific technical solution adopted by the present invention is:

[0006] A foaming device, used for hot bath foaming of expandable microspheres and derivatives thereof, comprising a hot bath device, a heating chamber, a pressure measuring device and a sealing body;

[0007] The heating chamber comprises an inner wall, a bottom wall and an outer wall connected in sequence; the thickness of the inner wall is uniform at all locations, and the thickness of the outer wall is uniform at all locations; a foaming cavity is formed between the inner wall, the bottom wall and the outer wall, and the foaming cavity is open at one end away from the bottom wall; the foaming cavity is strip-shaped;

[0008] The sealing body is used to form a sealed space for at least a part of the foaming cavity; the sealed space is used to place the expandable microspheres and their derivatives;

[0009] The heat bath device is used to heat the sealed space through the inner wall and the outer wall by heat bath;

[0010] The pressure measuring device is used to measure the pressure of the sealed space through the sealing body.

[0011] Furthermore, the sealing body includes a sealing sheet and a force transmission rod;

[0012] The force transmission rod is a rigid rod, one end of which is fixedly arranged with the sealing sheet, and the other end is connected to the pressure measuring device, and is used to conduct the pressure of the sealed space to the pressure measuring device.

[0013] Furthermore, after the sealed space is formed, in the space, in the projection of the foaming device from the opening of the cavity to the bottom wall direction, the projection of the sealing sheet coincides with the projection of the bottom wall.

[0014] Furthermore, the inner wall, the outer wall and the foaming cavity are all annular.

[0015] Furthermore, the inner diameter of the inner wall is 30 - 100 mm, and the thickness is 1 - 3 mm; the inner diameter of the outer wall is 40 - 120 mm, and the thickness is 1 - 3 mm.

[0016] Furthermore, the pressure measuring device is a pressure sensor.

[0017] Furthermore, the heat bath device is an oil bath heater.

[0018] The present invention also proposes a foaming method based on the foaming device, including the following steps:

[0019] S101: Seal the expandable microspheres and their derivatives into the strip-shaped sealed space by using the sealing body;

[0020] S102: Heat the two outer walls of the strip-shaped sealed space by constant temperature heat bath until the pressure in the sealed space no longer rises;

[0021] S103: Quickly remove the sealing body to enable the expandable microspheres and their derivatives in the sealed space to obtain a foaming space;

[0022] Wherein: the pressure in the sealed space is measured through the force conduction of the sealing body.

[0023] The present invention also proposes a foaming pressure measuring method based on the foaming device, characterized in that the pressure measuring method is:

[0024] A sealing sheet is provided which is the same as the projection plane of the strip-shaped foaming cavity from the opening of the foaming cavity to the bottom of the foaming cavity. A sealed space for the expandable microspheres and their derivatives to be heated is formed in the foaming cavity through the sealing sheet. A rigid force transmission rod is fixedly arranged on the sealing sheet, and the pressure in the sealed space is calculated by measuring the expansion force of the force transmission rod away from the foaming cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is a structural diagram of the foaming device in the embodiment of the present invention;

[0027] Figure 2 It is a structural diagram of the heating chamber in the embodiment of the present invention;

[0028] Figure 3 It is an electron microscope observation diagram of the foaming result of a comparative example of the present invention;

[0029] Figure 4 It is an electron microscope observation diagram of the foaming result of a comparative example of the present invention;

[0030] Figure 5 It is an electron microscope observation diagram of the foaming result during the implementation process of the present invention;

[0031] Figure 6 It is an electron microscope observation diagram of the foaming result during the implementation process of the present invention;

[0032] Figure 7 It is an electron microscope observation diagram of the foaming result during the implementation process of the present invention;

[0033] Figure 8 It is an electron microscope observation diagram of the foaming result during the implementation process of the present invention;

[0034] Figure 9 It is a graph of the foaming time and foaming pressure changes during the foaming process of an implementation process of the present invention;

[0035] Figure 10 It is a graph of the foaming time and foaming pressure changes during the foaming process of an implementation process of the present invention;

[0036] Figure 11 It is a graph of the foaming time and foaming pressure changes during the foaming process of an implementation process of the present invention;

[0037] Figure 12It is a graph showing the changes in foaming time and foaming pressure during the foaming process of an embodiment of the present invention;

[0038] Wherein: 1. Heat bath device; 2. Sealed space; 3. Heating chamber; 4. Sealing piece; 5. Force transmission rod; 6. Pressure measuring device. Specific embodiments

[0039] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0040] The following illustrates the embodiments of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of them. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0041] It should be noted that the following describes various aspects of the embodiments within the scope of the appended claims. It should be obvious that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on the present invention, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, this device can be implemented and this method can be practiced using other structures and / or functions in addition to one or more of the aspects described herein.

[0042] It also needs to be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. The diagrams only show the components related to the present invention, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in its actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0043] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0044] In a specific embodiment of the present invention, a foaming device is proposed for the thermal bath foaming of expandable microspheres and their derivatives, such as Figure 1 shown, which includes a thermal bath device 1, a heating chamber 3, a pressure measuring device 6, and a sealing body;

[0045] The heating chamber 3 includes an inner wall, a bottom wall, and an outer wall connected in sequence; the thickness of the inner wall is uniform everywhere, and the thickness of the outer wall is uniform everywhere; a foaming cavity is formed between the inner wall, the bottom wall, and the outer wall, and one end of the foaming cavity away from the bottom wall is open; the foaming cavity is strip-shaped;

[0046] The sealing body is used to form a sealed space 2 for at least a part of the foaming cavity; the sealed space 2 is used to place expandable microspheres and their derivatives;

[0047] The thermal bath device 1 is used to heat the sealed space 2 through the inner wall and the outer wall by thermal bath;

[0048] The pressure measuring device 6 is used to measure the pressure of the sealed space 2 through the sealing body.

[0049] In this embodiment, a new structure of the heating chamber 3 is proposed. Compared with the existing tubular heating chamber 3, the difference is that a strip-shaped heating chamber 3 is adopted, which can make the expandable microspheres and their derivatives be heated evenly everywhere and have the same heating time during the foaming process. Therefore, it avoids the problems existing in the foaming process through the traditional tubular heating chamber 3: due to the uneven heating of each part of the test tube, the part close to the tube wall is heated more, while the center part is heated less, which will cause the foaming near the tube wall to be faster, even reaching the shrinkage stage, while the center part is heated slower, and the microspheres have not foamed to the maximum volume. Eventually, it will lead to fast foaming on the outer layer and slow foaming inside, resulting in uneven foaming.

[0050] As Figure 2 shown, the specific material used for the heating chamber 3 of the present invention is glass, forming a strip-shaped foaming cavity. The specific structure of the foaming cavity can be circular ring-shaped, arc strip-shaped, rounded rectangle-shaped, etc. in cross-section, all of which are foaming cavities with uniform thickness, so as to ensure uniform heating everywhere. In this embodiment, in order to save processing costs, two foaming tubes with different diameters are sleeved on a bottom wall, that is, the inner wall, the outer wall, and the foaming cavity are all ring-shaped. In order to ensure the sealing of the bottom wall, a high molecular soft material is used, or a glass material integrally formed with the inner wall and the outer wall is used.

[0051] In one embodiment, as Figure 1 shown, the sealing body includes a sealing sheet 4 and a force transmission rod 5;

[0052] The force transmission rod 5 is a rigid rod, one end of which is fixedly arranged with the sealing sheet 4, and the other end is connected to the pressure measuring device 6, and is used to transmit the pressure of the sealed space 2 to the pressure measuring device 6.

[0053] In this embodiment, the pressure measurement device 6 employs a pressure sensor.

[0054] In one embodiment, as Figure 2 shown, after the sealed space 2 is formed, in the space, in the projection of the foaming device from the opening to the bottom wall of the cavity, the projection of the sealing sheet 4 coincides with the projection of the bottom wall. In this embodiment, the sealing sheet 4 is in the shape of a circular ring and can fit the circular ring-shaped foaming cavity to seal the sealed space 2, so that the foaming raw material in the sealed space 2 continuously rises in pressure to the ideal foaming temperature after passing through the bath heat.

[0055] In one embodiment, a structural size of the heating chamber 3 with high efficiency and easy processing is proposed. The inner diameter of the inner wall is 30 - 100 mm, and the thickness is 1 - 3 mm; the inner diameter of the outer wall is 30 - 120 mm, and the thickness is 1 - 3 mm.

[0056] In one embodiment, the pressure measurement device 6 is a pressure sensor.

[0057] In one embodiment, as Figure 1 shown, the heat bath device 1 is an oil bath heater. During the foaming process, the lower end of the heating chamber 3 is immersed in the hot oil of the oil bath heater.

[0058] In one embodiment, a foaming method based on the above-mentioned foaming device is proposed, including the following steps:

[0059] S101: Seal the expandable microspheres and their derivatives into the strip-shaped sealed space 2 using a sealing body;

[0060] S102: Constantly heat the two outer walls of the strip-shaped sealed space 2 in a heat bath until the pressure in the sealed space 2 no longer rises;

[0061] S103: Quickly remove the sealing body to enable the expandable microspheres and their derivatives in the sealed space 2 to obtain a foaming space;

[0062] Wherein: The pressure in the sealed space 2 is measured through the force conduction of the sealing body.

[0063] In one embodiment, the pressure measurement method is:

[0064] Set a sealing sheet 4 that is the same as the projection plane of the strip-shaped foaming cavity from the opening of the foaming cavity to the bottom of the foaming cavity. Form a sealed space 2 for the expandable microspheres and their derivatives to be heated through the sealing sheet 4 in the foaming cavity. Fix a rigid force transmission rod 5 on the sealing sheet 4, and calculate the pressure in the sealed space 2 by measuring the expansion force of the force transmission rod 5 away from the foaming cavity. The pressure measurement method of this embodiment is proposed in combination with the foaming device, which can improve the efficiency of pressure measurement during the foaming process and reduce the cost of the foaming device.

[0065] The following further illustrates the comparison of the foaming processes of the above two microspheres in a traditional foaming device and the foaming device and method proposed in the present invention:

[0066] The initial foaming temperature of microsphere A is 100 °C, and the maximum temperature at which the microsphere expands is 150 °C. The initial foaming temperature of microsphere B is 90 °C, and the maximum temperature at which the microsphere expands is 140 °C.

[0067] Process 1:

[0068] 2 g of microsphere A and 0.5 g of silicone oil were stirred evenly and placed in a circular foaming tube with an inner diameter of 40 mm and an outer diameter of 50 mm. It was sealed with a sealing cover with a pressure rod connected to a pressure recorder and placed in an oil bath at 130 °C. When the pressure no longer changed, the pressure was removed to allow the microspheres to foam. The foaming time and the change diagram of the foaming pressure are as shown in Figure 9 shown, and the electron microscope observation diagram of the foaming result is as shown in Figure 5 shown.

[0069] Process 2:

[0070] It was basically the same as Process 1, except that the oil bath temperature was changed to 140 °C. The foaming time and the change diagram of the foaming pressure are as shown in Figure 10 shown, and the electron microscope observation diagram of the foaming result is as shown in Figure 6 shown.

[0071] Process 3:

[0072] It was basically the same as Process 1, except that the oil bath temperature was changed to 150 °C. The foaming time and the change diagram of the foaming pressure are as shown in Figure 11 shown, and the electron microscope observation diagram of the foaming result is as shown in Figure 7 shown.

[0073] Process 4:

[0074] It was basically the same as Process 1, except that the microspheres were replaced with microsphere B. The foaming time and the change diagram of the foaming pressure are as shown in Figure 12 shown, and the electron microscope observation diagram of the foaming result is as shown in Figure 8 shown.

[0075] Comparative Example 1 using a traditional foaming device:

[0076] 2 g of microsphere A and 0.5 g of silicone oil were stirred evenly and placed in a circular foaming tube with an inner diameter of 40 mm, an outer diameter of 50 mm, and a thickness of 2 mm. After maintaining the same foaming time as in Process 1, the heat source was removed. The electron microscope observation diagram of the foaming result is as shown in Figure 3 shown.

[0077] Comparative Example 2 using a traditional foaming device:

[0078] Basically the same as Comparative Example 1, except that the foaming tube is replaced with a cylindrical foaming tube with a diameter of 30 mm and a thickness of 2 mm. The electron microscope observation diagram of the foaming result is as Figure 4 shown.

[0079] It can be seen from the figure that: the particle sizes of the foamed microspheres A obtained at different temperatures in processes 1-3 are relatively uniform and well-dispersed. At the same time, as the heating temperature approaches the maximum foaming temperature, the particle sizes of the microspheres also increase. For the microspheres B in process 4, the dispersibility and the uniformity of the particle sizes are also relatively good. In Comparative Example 1, without applying pressure, some microspheres have reached the shrinkage stage, while some microspheres have not yet foamed. In Comparative Example 2, with a cylindrical foaming tube, the heating is uneven. It can be seen that a large number of microspheres have entered the shrinkage stage, and the microspheres are bonded together with very poor dispersibility. Both Comparative Example 1 and Comparative Example 2 are caused by uneven heating during the foaming of the microspheres. By comparison, it can be known that the foaming device and the foaming method of the present invention can effectively improve the problems of uneven heating and asynchronous foaming of the microspheres.

[0080] As mentioned above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A foaming device for the thermal bath foaming of expandable microspheres and their derivatives, characterized in that: it includes a thermal bath device, a heating chamber, a pressure measuring device and a sealing body; the heating chamber includes an inner wall, a bottom wall and an outer wall connected in sequence; the thickness of the inner wall is uniform everywhere, and the thickness of the outer wall is uniform everywhere; a foaming cavity is formed between the inner wall, the bottom wall and the outer wall, and one end of the foaming cavity away from the bottom wall is open; the foaming cavity is strip-shaped; the sealing body is used to form a sealed space for at least a part of the foaming cavity; the sealed space is used to place the expandable microspheres and their derivatives; the thermal bath device is used to thermally bath and heat the sealed space through the inner wall and the outer wall; the pressure measuring device is used to measure the pressure of the sealed space through the sealing body.

2. The foaming device according to claim 1, characterized in that: the sealing body includes a sealing sheet and a force transmission rod; the force transmission rod is a rigid rod, one end is fixedly arranged with the sealing sheet, and the other end is connected to the pressure measuring device, and is used to conduct the pressure of the sealed space to the pressure measuring device.

3. The foaming device according to claim 2, characterized in that: after the sealed space is formed, in the sealed space, in the projection of the foaming device from the opening of the foaming cavity to the bottom wall direction, the projection of the sealing sheet coincides with the projection of the bottom wall.

4. The foaming device according to claim 1, characterized in that: the inner wall, the outer wall and the foaming cavity are all annular strips.

5. The foaming device according to claim 1, characterized in that: the inner diameter of the inner wall is 30 - 100 mm, and the thickness is 1 - 3 mm; the inner diameter of the outer wall is 40 - 120 mm, and the thickness is 1 - 3 mm.

6. The foaming device according to claim 1, characterized in that: the pressure measuring device is a pressure sensor.

7. The foaming device according to claim 1, characterized in that: the thermal bath device is an oil bath heater.

8. A foaming method based on the foaming device according to any one of claims 1 to 7, characterized in that, it includes the following steps: S101: Seal the expandable microspheres and their derivatives into the strip-shaped sealed space by using the sealing body; S102: Thermally bath and heat the two outer walls of the strip-shaped sealed space at a constant temperature until the pressure in the sealed space no longer rises; S103: Quickly remove the sealing body to enable the expandable microspheres and their derivatives in the sealed space to obtain a foaming space; wherein: the pressure in the sealed space is measured through the force conduction of the sealing body.

9. A foaming pressure measuring method based on the foaming device according to any one of claims 1 to 7, characterized in that, the pressure measuring method is: Set a sealing sheet that is the same as the projection plane of the strip-shaped foaming cavity from the opening of the foaming cavity to the bottom of the foaming cavity. Form a sealed space for the expandable microspheres and their derivatives to be heated through the sealing sheet in the foaming cavity. Fix a rigid force transmission rod on the sealing sheet, and calculate the pressure in the sealed space by measuring the expansion force of the force transmission rod away from the foaming cavity.

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