A process for the production of extruded foamed profiles

Abstract

This application relates to a production process for extruded foamed profiles, belonging to the technical field of composite material molding. The process involves adding material one to an extrusion device, where material one flows in the main channel; adding material two to the extrusion device, where material two flows into the main channel from a secondary channel, thus mixing material one and material two; the mixed material one and material two enter a mold, where they are shaped to form a preliminary product; the preliminary product then enters a cooling zone, where it is cooled to form the final product. In production, material one and material two are mixed, and the resulting foamed product has material two integrally formed with material one, with material two distributed among the material one particles, thus improving the performance of the foamed product. If material two is a high-strength material, it can increase the overall strength of material one; if material two is a different color from material one, the mixture of material two and material one can form foamed products of two or more colors.

Description

Technical Field

[0001] This application relates to the technical field of composite material molding, and in particular to a production process for extruded foam profiles. Background Technology

[0002] Extrusion foaming refers to the process of producing foamed materials using extrusion. A foaming agent is mixed with resin and other materials and added to an extruder. The material melts and plasticizes, reaching the decomposition temperature of the foaming agent. However, due to the screw back pressure and the closed state of the die head, foaming cannot occur within the barrel. The material reaches the setter where it foams and sets, forming a skin-like surface layer and a foamed core layer.

[0003] In existing extrusion foaming processes, raw materials are generally mixed uniformly before entering the extruder, ensuring a uniform surface finish for the extruded profiles. However, achieving certain specific properties often requires a larger quantity of material, and the desired results may not be obtained, leading to material waste. Therefore, it is necessary to improve the existing extrusion foaming process. Summary of the Invention

[0004] In order to improve the performance of foamed products, this application provides a production process for extruded foamed profiles.

[0005] The technical solution for the production process of extruded foamed profiles provided in this application is as follows:

[0006] A manufacturing process for extruded foam profiles includes the following steps:

[0007] Step S1: Add material one into the extrusion equipment, and material one flows in the main channel;

[0008] Step S2: Add material two to the extrusion equipment. Material two flows from the secondary channel into the main channel to mix material one and material two.

[0009] Step S3: The mixed material 1 and material 2 enter the mold, and after being shaped by the mold, the initial product is formed;

[0010] Step S4: The initial product enters the cooling zone and is cooled to form the final product.

[0011] By adopting the above technical solution, in the production process, material one and material two are mixed to produce a foamed product. Material two is integrally molded with material one, and material two is distributed among material one, thereby improving the performance of the foamed product. If material two is a high-strength material, then material two can improve the overall strength of material one; if material two is a material of a different color than material one, the mixture of material two and material one can form foamed products of two or more colors.

[0012] Optionally, the extrusion device has a main channel for material one to flow through, a feed bar is radially inserted through the extrusion device, the feed bar has a secondary channel for material two to flow through, and the feed bar has a flow hole for material two to flow into the main channel.

[0013] By adopting the above technical solution, the feed bar provides a path for material 2 to enter the main channel, and the feed bar is radially inserted into the extrusion equipment. Material 2 flowing out from the secondary channel is mixed with material 1, so that material 1 and material 2 are mixed evenly.

[0014] Optionally, the direction in which material two flows out of the flow hole is opposite to the direction in which material one flows.

[0015] By adopting the above technical solution, when material 2 flows out of the flow hole, material 2 and material 1 collide. Due to the large flow rate of material 1, material 2 will flow together with material 1 after colliding with material 1. However, after material 2 and material 1 collide, material 2 will be more easily diffused in material 1, resulting in more contact between material 2 and material 1 and more uniform mixing.

[0016] Optionally, step S4 may further include the following steps:

[0017] Step S4-1: The initial product enters the shrinkage section and is cooled by the first circulating water cooling system. Then, the initial product enters the horizontal extension section through the shrinkage opening.

[0018] By adopting the above technical solution, since foamed products are stretched and pulled by a traction machine, the initial product coming out of the mold is relatively soft and is prone to breakage after being subjected to traction force. The initial product is cooled and cooled by the first circulating water cooling, so that the initial product has a certain hardness and is not easy to break after being stretched.

[0019] Optionally, the temperature of the first circulating water cooling stage is 40℃-60℃.

[0020] By adopting the above technical solution, a water temperature of 40℃-60℃ can provide cooling for the initial product, but the cooling speed and cooling degree are not high. This is because after the first round of circulating water cooling, the product will undergo compression at the neck. The temperature in this range is just enough to make the product both resistant to traction and able to be compressed.

[0021] Optionally, step S4 further includes the following steps:

[0022] Step S4-2: When the initial product extends horizontally, the gas in the air pressure chamber cools the surface of the initial product.

[0023] By adopting the above technical solution, the initial product is squeezed and wrinkled as it enters the horizontal extension section from the constriction. To maintain this wrinkled shape, air cooling is used to rapidly cool and shape the surface of the initial product, hardening the wrinkles and ensuring that the initial product retains its wrinkled shape after passing through the entire horizontal extension section. Air cooling can cool the surface of the initial product much faster than water cooling because the gas in the air chamber has a higher pressure, and the gas is sprayed onto the surface of the initial product at a faster speed, allowing the gas to quickly carry away the heat from the surface of the initial product, thus rapidly cooling the surface. However, the gas does not act on the interior of the initial product, leaving the interior relatively soft and malleable.

[0024] Optionally, the horizontal extension is provided with a pressure chamber and an air outlet communicating with the pressure chamber, and the air outlet is located at the inlet of the horizontal extension.

[0025] By adopting the above technical solution, the gas in the air pressure chamber is sprayed onto the surface of the initial product through the air outlet, and the air outlet is set at the inlet of the horizontal extension, so that the surface of the initial product hardens as soon as it is compressed.

[0026] Optionally, step S4 further includes the following steps:

[0027] Step S4-3: After air cooling, the horizontal extension section is cooled again by a second circulating water cooling system.

[0028] By adopting the above technical solution, the initial product is cooled as a whole through a second circulating water cooling system.

[0029] Optionally, the temperature of the second circulating water cooling is 10℃-30℃.

[0030] By adopting the above technical solution, the second circulating water cooling needs to cool down the entire initial product, and this cooling is overall and continuous, so a lower water temperature is required.

[0031] Optionally, step S4 further includes the following steps:

[0032] Step S4-4: The horizontal extension section is cooled down for the initial product by spraying water.

[0033] By adopting the above technical solution, the initial product is cooled better by a second round of circulating water cooling followed by spray water cooling.

[0034] In summary, this application includes at least one of the following beneficial technical effects:

[0035] 1. In production, material one and material two are mixed to produce a foamed product. Material two is integrally molded with material one, and material two is distributed between material one. Material two improves the performance of the foamed product.

[0036] 2. When material two is flushed with material one, material two will diffuse more easily in material one, resulting in more contact between material two and material one and more uniform mixing;

[0037] 3. The surface of the initial product is rapidly cooled and shaped by air cooling, which hardens the wrinkles and allows the initial product to maintain the shape of the surface wrinkles after passing through the entire horizontal extension. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall structure of the foaming production equipment according to an embodiment of this application.

[0039] Figure 2 This is a cross-sectional view of the feed bar inserted into the main channel according to an embodiment of this application.

[0040] Figure 3 This is a cross-sectional view of the contraction portion according to an embodiment of this application.

[0041] Figure 4 This is a schematic diagram of the structure of the air pressure chamber in the second circulating water channel according to an embodiment of this application.

[0042] Explanation of reference numerals in the attached drawings: 1. Extruder; 11. Main runner; 2. Die; 3. Cooling zone; 31. Shrinkage section; 311. Narrowing; 32. Horizontal extension section; 321. Moving channel; 322. Air pressure chamber; 323. Air outlet; 324. Second circulating water channel; 325. Spray water cooling; 33. First circulating water channel; 4. Feed bar; 41. Secondary flow channel; 42. Flow hole; 5. Traction machine. Detailed Implementation

[0043] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0044] This application discloses a production process for extruded foam profiles.

[0045] Reference Figure 1 The foaming production equipment for extruded sheets includes an extrusion unit, a mold 2, and a cooling zone 3. The mold 2 is connected to the extruder 1, and the cooling zone 3 is connected to the end of the mold 2 away from the extruder 1. In this embodiment, the extrusion unit is the extruder 1. During production, the raw material is first placed into the extruder 1, and the extrusion forces the raw material into the mold 2. After being shaped by the mold 2, the product enters the cooling zone 3, and after cooling, the final product is formed.

[0046] See Figure 1 and Figure 2 The extruder 1 has a main channel 11, and material 1 is added into the main channel 11 and enters the mold 2 through the main channel 11.

[0047] In addition, a feed rod 4 is radially inserted into the extruder 1. The feed rod 4 is rotatably connected to the extruder 1, allowing it to rotate along its main axis and penetrate into the main channel 11. The feed rod 4 can be a cuboid, a cylinder, or any other shape that can penetrate into the main channel 11. In this embodiment, the feed rod 4 is a cylinder, as a cylinder is less likely to obstruct the flow of material within the main channel 11.

[0048] The feed bar 4 has a secondary flow channel 41. Material 2 is added into the secondary flow channel 41 and flows in the secondary flow channel 41. The feed bar 4 has a flow hole 42 in the radial direction. The flow hole 42 is connected to the secondary flow channel 41 and the main flow channel 11. Material 2 enters the main flow channel 11 from the secondary flow channel 41 through the flow hole 42.

[0049] Specifically, there can be one or more flow holes 42, and the specific number can be set according to actual needs. When there are multiple flow holes 42, the multiple flow holes 42 are spaced apart along the length direction of the feed bar 4, so that the multiple flow holes 42 are discharged in a row. In other embodiments, the multiple flow holes 42 can also be arranged in two or more rows.

[0050] Furthermore, since the feed bar 4 can rotate within the extruder 1, the orientation of the flow hole 42 within the main channel 11 will also change. Commonly, the orientation of the flow hole 42 is the same as the flow direction of the material 1 within the main channel 11, or the orientation of the flow hole 42 is opposite to the flow direction of the material 1 within the main channel 11; of course, in other embodiments, the flow hole 42 may also be oriented in other directions according to actual needs.

[0051] When the orientation of the flow hole 42 is the same as the flow direction of material one in the main channel 11, material two flows out of the flow hole 42 and flows together with material one, so that material two and material one are mixed stably. After the product is formed, material two is arranged more regularly in material one.

[0052] When the orientation of the flow hole 42 is opposite to the flow direction of material one in the main channel 11, material two flows out of the flow hole 42 and clashes with material one. However, due to the large flow rate of material one, after material one and material two clash and mix, they will still enter the mold 2 along the main channel 11. After material one and material two clash, they have more contact and mix more evenly; after the product is formed, material two is also more widely distributed among material one.

[0053] See Figure 1The cooling zone 3 includes a shrinkage section 31 and a horizontal extension section 32. The shrinkage section 31 is connected to the outlet of the mold 2, and the horizontal extension section 32 is connected to the end of the shrinkage section 31 away from the mold 2. The product coming out of the mold 2 is defined as the initial product. The initial product first enters the shrinkage section 31, and then enters the horizontal extension section 32.

[0054] The contraction section 31 has a funnel-shaped constriction 311 at one end near the horizontal extension section 32. When the initial product passes through the constriction 311, the initial product is compressed because the constriction 311 is small. At this time, wrinkles will appear on the outer surface of the initial product. Then the initial product with wrinkles on the outer surface enters the horizontal extension section 32.

[0055] Generally, the outlet of the horizontal extension section 32 is equipped with a traction machine 5, which pulls the final product out of the horizontal extension section 32. Therefore, the initial product coming out of the mold 2 will also be subject to traction force. However, since the initial product coming out of the mold 2 is relatively soft, it is easy to break after being subjected to traction force. Therefore, the shrinkage section 31 is equipped with a first circulating water cooling.

[0056] See Figure 3 The shrinkage section 31 has a first circulating water channel 33 inside, which is filled with cooling liquid. In this embodiment, the cooling liquid is water. The water is connected to a water source through a water pipe, so that the water source can continuously replenish the first circulating water channel 33 with water.

[0057] It should be noted that the temperature of the cooling liquid in the first circulating water channel 33 is controlled between 40℃ and 60℃. This is because the initial product is relatively soft when it comes out of the mold 2. Water at 40℃-60℃ can cool the initial product and give it a certain degree of hardness, so that the initial product is not easy to break when subjected to traction. However, water at this temperature cannot completely cool the initial product, so the initial product still has the ability to be squeezed and shaped, so that the initial product can be compressed when passing through the necking 311.

[0058] See Figure 1 and Figure 4 The horizontal extension 32 has air cooling, a second circulating water cooling and spray water cooling 325. Air cooling is used to shape the surface of the initial product, so that the surface of the initial product is hardened and shaped. Then, the second circulating water cooling is used to cool the initial product as a whole. Finally, water is sprayed onto the initial product to cool it to room temperature, thereby forming the final product.

[0059] As the initial product enters the horizontal extension section 32 from the constriction 311, it will be squeezed and wrinkled. In order to maintain this wrinkled shape, the surface of the initial product is rapidly cooled and shaped by air cooling, so that the wrinkles harden. After the initial product passes through the entire horizontal extension section 32, it can still maintain the wrinkled shape on the surface. If there is no air cooling process, the surface of the initial product will be smoothed after passing through the entire horizontal extension section 32, and the surface of the final product will be relatively smooth, and it will not be able to maintain the wrinkled feature.

[0060] Specifically, the horizontal extension 32 has a moving channel 321 for the initial product to move. The initial product moves within the moving channel 321 by the traction of the traction machine 5. The horizontal extension 32 has a pressure chamber 322, which is connected to an air pump. The air pump provides high-pressure gas to the pressure chamber 322. The horizontal extension 32 has an air outlet 323 at the entrance of the moving channel 321. The air outlet 323 is connected to the pressure chamber 322. The gas in the pressure chamber 322 enters the moving channel 321 through the air outlet 323, thereby impacting the surface of the initial product and removing the heat from the surface of the initial product.

[0061] The air outlet 323 can be one or several; its shape can be circular or elongated, as long as it can blow the gas in the pressure chamber 322 onto the surface of the initial product. In this embodiment, to increase the cooling area of ​​the initial product, the air outlet 323 is set to an elongated shape. The gas flow rate is 0.5 m³ / s. 3 / min-1m 3 Between / min, the gas velocity from the air pressure chamber 322 to the surface of the initial product is relatively fast, which in turn makes the cooling rate of the initial product surface faster.

[0062] The horizontal extension 32 has a second circulating water channel 324. The second circulating water channel 324 operates on the same principle as the first circulating water channel 33, both using water to cool the initial product and achieve the purpose of cooling the initial product. However, the difference between the second circulating water channel 324 and the first circulating water channel 33 lies in the water temperature. The water temperature in the second circulating water channel 324 is controlled between 10℃ and 30℃, using lower-temperature water to rapidly cool the initial product.

[0063] Furthermore, the second circulating water channel 324 surrounds the air pressure chamber 322, and the water in the second circulating water channel 324 cools the gas in the air pressure chamber 322. Because the temperature inside the actual production workshop is high, the air temperature inside the workshop is also high. If the air inside the workshop is used directly to cool the initial product, the effect will be poor. Therefore, the air is first cooled by the second circulating water channel 324, and then the air acts on the initial product, making the air cooling effect better.

[0064] In another embodiment, multiple air pressure chambers 322 can be provided. Each air pressure chamber 322 is cylindrical and surrounded by a second circulating water channel 324. Each air pressure chamber 322 is connected to an air inlet pipe, through which air is added to the air pressure chamber 322. Each air pressure chamber 322 has an air outlet 323, through which the gas in the air pressure chamber 322 is blown onto the initial product.

[0065] The horizontal extension section 32 is equipped with several nozzles that spray water to cool the initial product. After the initial product passes through the second circulating water cooling stage, it exits from the moving channel 321. At this time, water is sprayed onto the initial product through the nozzles to cool the entire initial product.

[0066] In addition, the length of the spray water cooler 325 is greater than the length of the second circulating water cooler. In this embodiment, the length of the spray water cooler 325 is twice the length of the second circulating water cooler.

[0067] This embodiment also discloses a production process for extruded foamed profiles, the specific steps of which are as follows:

[0068] Step S1: Add material one into the extrusion equipment, and material one flows in the main channel 11;

[0069] Step S2: Add material two to the feed bar 4. Material two flows from the secondary channel 41 into the main channel 11 to mix material one and material two.

[0070] Step S3: The mixed material 1 and material 2 enter mold 2, and after being shaped by mold 2, the initial product is formed;

[0071] Step S4: The initial product enters the cooling zone 3 and is cooled to form the final product.

[0072] Step S4 further includes the following specific steps:

[0073] Step S4-1: The initial product enters the shrinkage section 31 and is cooled by the first circulating water cooling. Then the initial product enters the horizontal extension section 32 through the constriction 311. The water temperature in the first circulating water cooling is 40℃-60℃.

[0074] Step S4-2: When the initial product extends horizontally to the 32nd section, the gas in the air pressure chamber 322 is used to cool the surface of the initial product.

[0075] Step S4-3: After air cooling, the horizontal extension 32 is cooled again by a second circulating water cooling system; the water temperature of the second circulating water cooling system is 10℃-30℃.

[0076] Step S4-4: The horizontal extension 32 uses a spray water cooling 325 to cool the initial product for the final stage.

[0077] Test method:

[0078] Test 1

[0079] (1) Basic formula: After mixing the basic formula without antistatic agent additives, the HDPE substrate foam profile is directly extruded through the mold. Six samples with a length × width × thickness of 50cm × 10cm × 2cm are taken and recorded as sample A1 to sample A6 respectively.

[0080] (2) Comparative Example 1: Based on the basic formula, 30 wt% of HDPE base material (15 wt% effective antistatic content) was replaced with an effective content of 50 wt% HDPE carrier antistatic masterbatch. After all raw materials were fully mixed, they were directly extruded through a mold to obtain HDPE base foam profiles, thereby obtaining foamed products with antistatic properties. Six samples with a length × width × thickness of 50 cm × 10 cm × 2 cm were taken and recorded as samples B1 to B6 respectively.

[0081] (3) Application Example 1: On the basic formula, 12.5% ​​of HDPE base material (6.25wt% effective content of antistatic agent) is replaced by 50% effective content of HDPE carrier antistatic masterbatch. After extrusion through the above-mentioned production process of this application, the HDPE base material containing antistatic agent flows in from the secondary channel and other components flow in from the main channel, thereby obtaining HDPE base foam profile with antistatic properties. Six samples with length × width × thickness of 50cm × 10cm × 2cm are taken and recorded as sample C1 to sample C6 respectively.

[0082] Table 1. Composition Formula 1

[0083]

[0084] The surface resistivity meters (model SR110) were used to test samples A1 to A6, B1 to B6, and C1 to C6 obtained above. The specific test results are shown in the table below.

[0085] Table 2. Resistance Test Results

[0086]

[0087]

[0088] Conclusion: First, the surface resistivity of foamed wood-plastic composite products made from the basic formula is ≥10 Ω·cm. 12 The resistance of Ω indicates that surface charge accumulates on the surface and cannot be effectively conducted; secondly, the surface resistivity of the foamed wood-plastic product in Comparative Example 1 is 10 Ω. 9 Ω-10 11Ω, this is because its surface forms discontinuous conductive channels, thus possessing a certain antistatic effect; while the foamed wood-plastic product made using the foaming production process of this application in Application Example 1 has a surface resistivity of 10 Ω. 9 Ω-10 10 Ω, because the surface of foamed wood-plastic products forms layered conductive channels in the cross-section. This not only requires less antistatic agent, but also has a more efficient surface conductivity, which is better than the basic formula and Comparative Example 1.

[0089] Test 2

[0090] (1) Basic formulation: HDPE substrate foam profiles are obtained by directly extruding the basic formulation without ultra-high molecular weight polyethylene reinforcing material through a mold, and then 6 samples are taken as samples D1 to D6.

[0091] (2) Comparative Example 2: Ultra-high molecular weight polyethylene was used to replace 20 wt% of HDPE in the total formula. After all materials were mixed evenly, they were extruded through a mold to obtain HDPE-based foamed profiles. Six samples were then taken as samples E1 to E6. (3) Application Example 2: Ultra-high molecular weight polyethylene was used to replace 10 wt% of HDPE in the total formula. After extrusion through the above-mentioned production process of this application, ultra-high molecular weight polyethylene flowed in from the secondary channel and other components flowed in from the main channel to obtain HDPE-based foamed profiles. Six samples were then taken as samples F1 to F6.

[0092] Table 3, Composition Formula 2

[0093]

[0094] According to GB / T 1040 standard, foamed profiles of the basic formulation, Comparative Example 2, and Application Example 2 were sampled and their tensile strength was tested. The test results are shown in the table below.

[0095] Table 4. Tensile Strength Test Results

[0096]

[0097]

[0098] Conclusion: First, the tensile strength is 16-18 MPa. Second, the tensile strength of directly mixed and uniformly prepared materials reaches 21-23 MPa. While the foaming production process used in this application reduces the amount of added polyethylene by 10%, the tensile strength can still reach 22-23 MPa under the same test conditions. This application achieves a similar tensile strength improvement as Comparative Example 2 by using a small amount of added ultra-high molecular weight polyethylene, while exhibiting smaller performance differences and better material uniformity and stability.

[0099] Test 3

[0100] Method 1: The basic formula is directly processed through conventional processes, that is, the structure of the shrinkage section is not used in this application, and the cooling device of this application is replaced with a conventional cooling water tank for testing. Finally, HDPE substrate foamed profiles are obtained, and 6 samples are taken as samples G1 to G6.

[0101] Method 2: Take 6 samples of HDPE substrate foam profiles extruded using the foaming process of this application, and label them as samples H1 to H6.

[0102] Testing method: The HDPE substrate foam profiles manufactured by the two methods were tested using a pendulum friction coefficient meter. The results are shown in Table 5 below: Table 5, Friction coefficient test results

[0103]

[0104] Conclusion: HDPE substrate foam profiles extruded using the production process of this application have greater surface friction and better matte finish, which also proves that HDPE substrate foam profiles manufactured using the production process of this application have a more obvious skin-breaking effect.

[0105] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A production process for extruded foamed profiles, characterized in that: Includes the following steps: Step S1: Add material one into the extrusion equipment, and material one flows in the main channel (11); Step S2: Add material two to the extrusion equipment. Material two flows from the secondary channel (41) into the main channel (11) to mix material one and material two. Step S3: The mixed material 1 and material 2 enter the mold (2), and after being shaped by the mold (2), the initial product is formed; Step S4: The initial product enters the cooling zone (3) and is cooled to form the final product; The extrusion equipment has a main channel (11) for material one to flow through, and a feed bar (4) is radially inserted through the rear half of the extrusion equipment. The feed bar (4) has a secondary channel (41) for material two to flow through, and the feed bar (4) has a flow hole (42) for material two to flow into the main channel (11). The direction in which material 2 flows out from the flow hole (42) is opposite to the direction in which material 1 flows; Step S4 also includes the following steps: Step S4-1: The initial product enters the shrink section (31), and is cooled by the first circulating water cooling. Then the initial product enters the horizontal extension section (32) through the shrinkage opening (311).

2. The production process of extruded foamed profiles according to claim 1, characterized in that: The temperature of the first circulating water cooling system is 40℃-60℃.

3. The production process of extruded foamed profiles according to claim 1, characterized in that: Step S4 further includes the following steps: Step S4-2: When the initial product enters the horizontal extension section (32), the gas in the air pressure chamber (322) cools the surface of the initial product.

4. The production process of extruded foamed profiles according to claim 1, characterized in that: The horizontal extension (32) is provided with a pressure chamber (322) and an air outlet (323) communicating with the pressure chamber (322). The air outlet (323) is located at the entrance of the horizontal extension (32).

5. The production process of extruded foamed profiles according to claim 3, characterized in that: Step S4 further includes the following steps: Step S4-3: After air cooling, the horizontal extension (32) is cooled again by the second circulating water cooling to cool the initial product.

6. The production process of an extruded foamed profile according to claim 5, characterized in that: The temperature of the second circulating water cooling system is 10℃-30℃.

7. The production process of an extruded foamed profile according to claim 5, characterized in that: Step S4 further includes the following steps: Step S4-4: The horizontal extension (32) is cooled down for the initial product by spray water cooling (325).

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