Inflatable continuous foaming device and foaming method thereof
By adopting an inflatable continuous foaming device in physical foaming technology, the push space between the thread of the screw and the barrel is increased, providing expansion deformation space for the foaming material, and solving the uneven foaming in the prior art The problem of poor continuity between the equipment has achieved efficient and stable foaming process and low energy consumption production.
Patent Information
- Application Number
- CN202411809067.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-10
- Publication Date
- 2025-02-14
AI Technical Summary
The existing physical foaming technology requires complex mechanical devices during the processing process, which consumes a lot of resources, is uneven foaming, poor product density, poor continuity between equipment, affecting production efficiency and product quality.
The inflatable continuous foaming device is adopted, including a barrel, a screw, a foam box, an air injection mechanism and a heating mechanism. The material pushing space between the thread of the screw and the barrel is gradually increased, providing expansion and deformation space for the foaming material. , ensure uniformity of bubble distribution and continuity of foam structure.
The continuity of the foaming process is achieved, the conversion demand between equipment is reduced, the production efficiency is improved, the utilization rate of raw materials is stabilized, and energy consumption and production costs are reduced.
Smart Images
Figure CN119427631A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of foaming, in particular to an inflatable continuous foaming device and a foaming method thereof. Background Art
[0002] At present, with the diversification and customization of plastic products, materials such as EVA, TPU, PE, PP, PS, PVC, POE, EPDM, EAA, EMB, EMA, EPOPE, PA, PA12 elastomer, POM, POK, PEEK, etc. have been widely used in the manufacturing fields of various plastic products and thermoplastic products, such as: shoemaking, blow molding, automotive industry, electrical appliances and other products.
[0003] There are two main methods to make products lightweight: physical foaming and chemical foaming. Compared with chemical foaming agents, physical foaming agents can achieve greater foaming effects, but the processing requirements are higher and require more complex mechanical equipment technology. The established process involves a wide range of processes, which requires more resources for product processing. First, the raw materials and auxiliary materials such as vulcanizers, plasticizers, and cross-linking agents need to be mixed and foamed. The traditional foaming method uses chemical foaming and adds other substances inside the particles as foaming agents. However, harmful gases are usually produced during the foaming process, which is not conducive to environmental protection. The use of physical foaming to perform microporous foaming on the foaming raw materials is a new process. Compared with traditional chemical foaming, it does not contain other added materials and does not pollute the environment. How to control the microporous foaming inside the foaming material is a key technical problem that needs to be solved urgently.
[0004] The existing method adopts the method of melting and mixing the foaming raw materials through an extruder lamp and then putting them into a reactor, and filling the reactor with high-pressure carbon dioxide or nitrogen or a mixed gas, gradually increasing the pressure and temperature in the reactor, so that the high-pressure gas is filled into the foaming material, maintaining the pressure and penetrating for a period of time, and then quickly releasing the pressure. The foaming material coming out of the reactor is then placed in an oven or other processing unit for heating and pressurizing molding. The reactor is a special equipment with a high production cost, which is not conducive to large-scale production. In addition, the foaming process is not continuous between multiple equipments. During the transfer process, the foaming material will foam unevenly due to changes in temperature and pressure, and there will be differences in local foam density. The small bubbles formed by the gas during the foaming process may burst due to mechanical vibration or pressure changes, resulting in increased density or uneven structure of the final product. The switching between equipment causes the foaming material to be contaminated, such as the invasion of dust, impurities or other chemicals, which affects the foaming effect and product quality. The poor continuity between equipment may lead to low production efficiency and difficulty in ensuring product quality consistency. Therefore, it is necessary to find a new solution based on the existing physical foaming so that the method of physical foaming to make the product lightweight can meet the needs of modern production. Summary of the invention
[0005] The object of the present invention is to provide an inflatable continuous foaming device to solve the problems raised in the above background technology.
[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an inflatable continuous foaming device, comprising a barrel, a screw screwed into the barrel, a foaming box connected to the barrel, an air injection mechanism and a heating mechanism, wherein the screw comprises a rod body and threads arranged in a spiral shape on the rod body, a feed port is provided at one end of the barrel, and a foaming outlet is provided at the other end, and the barrel is divided into a softening section, a melting and mixing section, a foaming section and a foaming section from the feed port to the foaming outlet, and a pushing space formed between the threads of the screw and the barrel is divided into a plurality of sections according to the sections. It gradually increases from the feed inlet to the foaming outlet, and the barrel is provided with injection ports corresponding to the melting and mixing section, the first foaming section and the second foaming section. The injection ports are connected to the gas injection mechanism, and the high-pressure gas penetrates into the interior of the foaming material and diffuses to the foaming box. The foaming box is divided into a pressure release expansion section and a molding section. The inlet of the pressure release expansion section is connected to the foaming outlet, the diameter of the pressure release expansion section is larger than the diameter of the foaming outlet, and the diameter of the molding section is larger than the diameter of the pressure release expansion section. The injection ports are set at multiple points and are evenly distributed on the barrel.
[0007] Furthermore, the screw is a single-screw structure, the diameter of the rod body gradually decreases from the feed inlet to the foaming outlet, the top diameter of the thread remains unchanged, and the pitch of the thread gradually widens from the feed inlet to the foaming outlet according to the segmentation, and the depth of the thread gradually deepens from the feed inlet to the foaming outlet.
[0008] Furthermore, an air channel is provided in the rod body, one end of the air channel is an air blowing port, air outlet holes are evenly opened on the surface of the rod body, and the air blowing port is connected to the air injection mechanism.
[0009] Furthermore, the air passages include three, which respectively correspond to the lengths of the melting and mixing section, the first foaming section, and the second foaming section.
[0010] Furthermore, each air channel has an air hole in its corresponding melting and mixing section, foaming section one or foaming section two.
[0011] Furthermore, a conveying component for driving the foaming material is arranged in the foaming box.
[0012] An inflation type continuous foaming method, the method comprising:
[0013] The foaming raw material is fed from the feed port, and the heating mechanism heats the barrel. The foaming raw material moves forward as the screw rotates, softens in the softening section to form a foaming melt, and high-pressure gas is injected through the injection port. In the molten mixing section, the high-pressure gas penetrates into the inside of the foaming melt to form bubble nuclei. In the first and second foaming sections, the bubble nuclei inside the melt gradually expand and grow to form a pre-foamed body. The pushing space formed between the screw thread and the barrel gradually increases from the feed port to the foaming outlet according to the segmentation, providing deformation space for expansion for foaming;
[0014] The heating mechanism heats the foaming box, and as the gas gradually diffuses into the foaming box, the pre-foamed body releases pressure and expands in the pressure release and expansion section, and is foamed and formed in the forming section.
[0015] Furthermore, before injecting the high-pressure gas through the injection port, the high-pressure gas is injected into the blowing port, and the high-pressure gas injected from the blowing port fills the entire screw through the gas outlet.
[0016] Furthermore, when high-pressure gas is injected from the injection port, a pressure gradient is formed in the barrel.
[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention adopts a screw for mixing and foaming, and the screw pushes the foaming raw materials forward when rotating, forming a strong shear force and mixing effect, effectively mixing the raw materials evenly, thereby improving the foaming effect, and injecting high-pressure gas through the injection port, and the high-pressure gas penetrates into the interior of the foaming material to foam, thereby ensuring the uniformity of bubble distribution and the continuity of the foam structure. At the same time, the pushing space formed between the screw thread and the barrel gradually increases from the feed port to the foaming outlet according to the segmentation, providing the foaming material with an expansion deformation space during the foaming process, connecting the barrel and the foaming box, and the pre-foamed body conveyed from the screw directly enters the foaming box for foaming, thereby forming a continuous foaming process from raw materials to finished products, reducing the conversion requirements between equipment, improving the continuity of the system, improving production efficiency, making the production process of the foaming material more stable, and the utilization rate of raw materials higher, and the gas in the barrel will diffuse to the foaming box, and there is no need to additionally pressurize the foaming box, so the energy consumption is lower and the production cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic structural diagram of the inflatable continuous foaming device of the present invention;
[0019] Figure 2 It is a schematic diagram of the screw structure in the inflatable continuous foaming device of the present invention;
[0020] Figure 3 It is a schematic diagram of the airway structure in the inflatable continuous foaming device of the present invention;
[0021] In the figure, 1-barrel, 11-feed port, 12-foaming outlet, 13-injection port, A-softening section, B-melt mixing section, C-foaming section one, D-foaming section two, 2-screw, 21-rod body, 211-air channel, 212-blowing port, 213-air outlet, 22-thread, 3-foaming box, E-pressure release expansion section, F-molding section. DETAILED DESCRIPTION
[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0023] like Figure 1 to Figure 3 As shown, this embodiment provides an inflatable continuous foaming device, including a barrel 1, a screw 2 screwed into the barrel 1 and driven by a driving mechanism, a foaming box 3 connected to the barrel 1, an injection mechanism and a heating mechanism; the driving mechanism includes a motor 41, a reduction box 42 and a coupling 43, the motor 41 is connected to the input shaft of the reduction box 42, and the output shaft of the reduction box 42 is connected to the screw 2 through the coupling 43; the injection mechanism includes an air storage tank and a high-pressure pump, and a valve is provided on the air storage tank; the heating mechanism heats the barrel 1 and the foaming box 3 to heat the foaming material. The heating mechanism is a prior art and can be heated by a heating plate, a heating block, etc., which will not be described in detail here.
[0024] One end of the barrel 1 is provided with a feed port 11, and the other end is a foaming outlet 12. For example, a hopper can be arranged on the barrel 1, and the hopper is connected to the feed port 11, and the foaming raw material is fed through the hopper. The barrel 1 is divided into a softening section A, a melting and mixing section B, a foaming section C and a foaming section D from the feed port 11 to the foaming outlet 12. The barrel 1 is provided with injection ports 13 corresponding to the melting and mixing section B, the foaming section C and the foaming section D. The injection ports are arranged at multiple points and are evenly distributed on the barrel 1, and are connected to the gas injection mechanism. The high-pressure gas penetrates into the interior of the foaming material and diffuses to the foaming box 2.
[0025] The screw 2 is a single screw structure, including a rod body 21 and a thread 22 arranged in a spiral shape on the rod body 21. The diameter of the rod body 21 gradually decreases from the feed port 11 to the foaming outlet 12, and is in a cone shape. The rear end of the rod body 21 corresponding to the second foaming section D is not provided with a thread. An air channel 211 is provided in the rod body 21, and one end of the air channel 211 is a blowing port 212. The air channel 211 includes 3 air channels, which are respectively set to the lengths of the melting and mixing section B, the first foaming section C and the second foaming section D. Each air channel 211 has an air hole in its corresponding melting and mixing section B, the first foaming section C or the second foaming section D. The surface of the rod body 21 is evenly provided with air outlet holes 213. The high-pressure pump is connected to a rotary joint through a pipeline, and a gas output channel is provided in the rotary joint. The rotary joint is connected to the output shaft of the reduction box 32 through a pipeline. A connecting channel connecting the gas output channel and the airway 211 is provided in the output shaft of the reduction box 32. The high-pressure gas can also be injected into the barrel 1 through the blowing port 212. The top diameter of the thread 22 remains unchanged and always maintains a certain distance from the barrel 1. The pitch of the thread 22 gradually widens from the feed port 11 to the foaming outlet 12 according to the segmentation, and the depth of the thread 22 gradually deepens from the feed port 11 to the foaming outlet 12, which adapts to the gradually increasing volume of the foaming material during the foaming process and provides a deformation space for expansion of the foaming material.
[0026] The foaming box 3 is divided into a pressure release expansion section E and a forming section F. The inlet of the pressure release expansion section E is connected to the foaming outlet 12. The inlet of the pressure release expansion section E is trumpet-shaped, which is convenient for the foaming material to enter the pressure release expansion section from the foaming outlet 12. The diameter of the pressure release expansion section E is larger than the diameter of the foaming outlet 12, which is 2 to 4 times the diameter of the foaming outlet 12. The diameter of the forming section F is larger than the diameter of the pressure release expansion section E, which is 1.5 to 2 times the diameter of the pressure release expansion section E. A conveying component for driving the foaming material is provided in the foaming box 3, and the conveying component can be conveyed by a mesh belt.
[0027] This embodiment also provides an inflation-type continuous foaming method, the method comprising:
[0028] The foaming raw material is fed from the feed port, and the heating mechanism heats the barrel. The foaming raw material moves forward as the screw rotates, softens in the softening section to form a foaming melt, and high-pressure gas is injected through the injection port. In the molten mixing section, the high-pressure gas penetrates into the inside of the foaming melt to form bubble nuclei. In the first and second foaming sections, the bubble nuclei inside the melt gradually expand and grow to form a pre-foamed body. The pushing space formed between the screw thread and the barrel gradually increases from the feed port to the foaming outlet according to the segmentation, providing deformation space for expansion for foaming;
[0029] The heating mechanism heats the foaming box, and as the gas gradually diffuses into the foaming box, the pre-foamed body releases pressure and expands in the pressure release and expansion section, and is foamed and formed in the forming section.
[0030] Specifically, the foaming raw material, which may be a mixture of one or more of EVA, TPR, TPU, PE, PP, PET, PTG, and PPS, or a mixture of one or more of EVA, TPR, TPU, PE, PP, PET, PTG, and PPS and auxiliary materials such as vulcanizers, plasticizers, and cross-linking agents, is fed from a hopper through a feed port 11 into a barrel 1, and a heating mechanism heats the barrel 1. The temperature of the softening section is 150 to 180° C., the temperature of the melt mixing section is 250 to 280° C., and the temperatures of the foaming section and the foaming section are both 150 to 250° C. As the screw 2 rotates forward, the foaming raw material softens in the softening section A to form a foaming melt, and the foaming The raw material gradually expands due to the heat. Since the pushing space formed between the screw thread and the barrel gradually widens, it can adapt to the expanded foaming material and squeeze the foaming material forward. The valve is opened, and the gas in the gas storage tank enters the high-pressure pump. The gas pressure of the high-pressure pump is set. The pressure of the injected gas is controlled by the high-pressure pump to obtain high-pressure gas, which includes any one of nitrogen, carbon dioxide, methane, ethane, propane, butane, and inert gas. The high-pressure gas is injected into the blowing port 212 through the gas storage tank and enters the melting and mixing section B, the foaming section C, and the foaming section D of the barrel 1 through the high-pressure gas injection port 13. Among them, the pressure of the softening section A is 1-5Pa, the pressure of the melting and mixing section B is 5-40Pa, and the pressure of the foaming section C is 5-60Pa. The pressure of the second foaming stage D is 5-100Pa. The high-pressure gas injected from the blowing port 212 fills the entire screw 2 through the outlet hole 213. The high-pressure gas injected from the injection port 13 penetrates into the interior of the foaming material in the melt mixing section B to form bubble nuclei. Since the high-pressure gas injected from the blowing port 212 fills the entire screw 2 through the outlet hole 213, when the high-pressure gas is injected from the injection port 13, a pressure gradient is formed in the barrel 1, which promotes the high-pressure gas to better penetrate into the interior of the foaming material, improves the penetration efficiency, improves the distribution of the airflow, avoids the uneven flow caused by the accumulation of high-pressure gas in the middle section, enables the high-pressure gas to penetrate more evenly, improves the uniformity of foaming, enhances the foaming effect, and the foaming material foams and expands. The pushing space formed between the screw thread and the barrel gradually increases, which can adapt to the expanding foaming material and squeeze the foaming material forward. In the first and second foaming stages, the bubble nuclei inside the melt gradually expand and grow to form a pre-foamed body. The heating mechanism heats the foaming box 3, the temperature of the pressure release expansion section E is 50-150°C, and the temperature of the molding section F is 20-150°C. As the gas gradually diffuses to the foaming box 3, the pressure of the pressure release expansion section E is 1-10Pa, and the pressure of the molding section F is 0-5Pa. The pre-foamed body enters the pressure release expansion section E through the trumpet-shaped inlet, slowly releases pressure and expands in the pressure release expansion section E, and foams and forms in the molding section F. The conveying component conveys the foaming material to the next process.
[0031] The present invention adopts a screw for mixing and foaming. When the screw rotates, it pushes the foaming raw materials forward, forming a strong shear force and mixing effect, effectively mixing the raw materials evenly, thereby improving the foaming effect, and injecting high-pressure gas through the injection port. The high-pressure gas penetrates into the interior of the foaming material to foam, thereby ensuring the uniformity of bubble distribution and the continuity of the foamed body structure. At the same time, the pushing space formed between the thread of the screw and the barrel gradually increases from the feed port to the foaming outlet according to the segmentation, thereby providing the foaming material with an expansion deformation space during the foaming process, and the barrel is connected to the foaming box. The pre-foamed body conveyed by the screw directly enters the foaming box for foaming, thereby forming a continuous foaming process from raw materials to finished products, reducing the conversion requirements between equipments, improving the continuity of the system, improving production efficiency, making the production process of the foaming material more stable, and achieving higher raw material utilization. Moreover, the gas in the barrel will diffuse to the foaming box, and there is no need to additionally pressurize the foaming box, thereby lowering energy consumption and reducing production costs.
[0032] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. An inflatable continuous foaming device, characterized in that: The invention comprises a barrel, a screw screwed into the barrel, a foaming box connected to the barrel, an injection mechanism and a heating mechanism, wherein the screw comprises a rod body and a thread arranged in a spiral shape on the rod body, a feed port is arranged at one end of the barrel, and a foaming outlet is arranged at the other end, the barrel is divided into a softening section, a melting and mixing section, a foaming section one and a foaming section two from the feed port to the foaming outlet, the pushing space formed between the thread of the screw and the barrel gradually increases from the feed port to the foaming outlet according to the segmentation, injection ports are arranged on the barrel corresponding to the melting and mixing section, the foaming section one and the foaming section two, the injection ports are connected to the injection mechanism, and the high-pressure gas penetrates into the interior of the foaming material and diffuses into the foaming box, the foaming box is divided into a pressure release expansion section and a molding section, the inlet of the pressure release expansion section is connected to the foaming outlet, the diameter of the pressure release expansion section is larger than the diameter of the foaming outlet, the diameter of the molding section is larger than the diameter of the pressure release expansion section, and the injection ports are arranged at multiple points and evenly arranged on the barrel.
2. The inflatable continuous foaming device according to claim 1, characterized in that: The screw is a single screw structure, the diameter of the rod body gradually decreases from the feed inlet to the foaming outlet, the top diameter of the thread remains unchanged, and the pitch of the thread gradually widens from the feed inlet to the foaming outlet according to the segmentation, and the depth of the thread gradually deepens from the feed inlet to the foaming outlet.
3. The inflatable continuous foaming device according to claim 1, characterized in that: An air channel is arranged in the rod body, one end of the air channel is an air blowing port, air outlet holes are evenly arranged on the surface of the rod body, and the air blowing port is connected to the air injection mechanism.
4. The inflatable continuous foaming device according to claim 3, characterized in that: The air passages include three, which are respectively arranged to correspond to the lengths of the melting and mixing section, the first foaming section and the second foaming section.
5. The inflatable continuous foaming device according to claim 4, characterized in that: Each air channel has an air hole in its corresponding melting and mixing section, foaming section one or foaming section two.
6. The inflatable continuous foaming device according to claim 1, characterized in that: The foaming box is provided with a conveying component for driving the foaming material.
7. An inflatable continuous foaming method, characterized in that: The method comprises: The foaming raw material is fed from the feed port, and the heating mechanism heats the barrel. The foaming raw material moves forward as the screw rotates, softens in the softening section to form a foaming melt, and high-pressure gas is injected through the injection port. In the molten mixing section, the high-pressure gas penetrates into the inside of the foaming melt to form bubble nuclei. In the first and second foaming sections, the bubble nuclei inside the melt gradually expand and grow to form a pre-foamed body. The pushing space formed between the screw thread and the barrel gradually increases from the feed port to the foaming outlet according to the segmentation, providing deformation space for expansion for foaming; The heating mechanism heats the foaming box, and as the gas gradually diffuses into the foaming box, the pre-foamed body releases pressure and expands in the pressure release and expansion section, and is foamed and formed in the forming section.
8. The inflatable continuous foaming method according to claim 7, characterized in that: Before injecting the high-pressure gas through the injection port, the high-pressure gas is injected into the blowing port, and the high-pressure gas injected from the blowing port fills the entire screw through the gas outlet.
9. The inflatable continuous foaming method according to claim 8, characterized in that: When high-pressure gas is injected from the injection port, a pressure gradient is formed in the barrel.