An extruder for optical-grade thermoplastic polyurethane elastomer films

Abstract

This invention relates to the field of plastic processing technology and discloses a special extruder for optical-grade thermoplastic polyurethane elastomer films. It includes an extruder housing for processing materials, a heating device for heating the materials, and a drive device for power transmission. A processing cavity is formed inside the extruder housing to provide space for material processing. A screw is movably sleeved within the processing cavity to continuously propel the material forward. This invention utilizes the relative rotation between a scraper roller and a screw thread to scrape the material adhering to the thread, separating the material from the thread in the direction of the scraper roller's rotation. The separated material then moves closer to the inner wall of the processing cavity near the scraper roller, reducing the gap between the material and the cavity wall, improving the heating effect, and allowing subsequent materials to propel the separated material forward with less force.

Description

Technical Field

[0001] This invention relates to the field of plastic processing technology, specifically to an extruder for optical-grade thermoplastic polyurethane elastomer films. Background Technology

[0002] In the processing of polyurethane elastic films, a single-screw extruder is typically used to heat and melt the raw material, which is then extruded under pressure. melt The oxidized material is extruded into a mold, and through subsequent processes such as blowing, stretching, cooling, and winding, a finished film is obtained.

[0003] Among them, the single-screw extruder uses the rotation of the screw to process the material. delivery The material is heated and melted by the heat generated by the external electric heating device and the screw extrusion and shearing. In this process, the screw is roughly divided into the feeding section (adding the main material, at which point the material fills the screw channel less than 1, that is, it is not fully filled) — melting section (the material is initially melted to form a solid-liquid mixture, at which point the material fills the screw channel less than 1, but greater than the filling section) — homogenization section (making the material mix evenly, at which point the material fills the screw channel less than 1) — metering section (making the filling of the melt in the screw channel equal to 1, thereby establishing pressure on the melt and completing the subsequent material extrusion).

[0004] In the melting and mixing sections, especially the melting section, the initially melted material is a viscous paste. this Paste-like materials are highly viscous and easily... Adhesion On the screw, Obstacles Subsequent materials of Flow, at this time, the screw and the extruder barrel The inner wall of the extruder has gaps, and the material filling degree here is less than 1. This results in a large gap between the material adhering to the screw and the inner wall of the extruder. The adhering material cannot directly contact the inner wall of the extruder, and the adhering material cannot directly exchange heat with the inner wall of the extruder. This reduces the efficiency of heating and melting the adhering material. Therefore, it is necessary to lengthen the stroke of the melting section to ensure sufficient heating and to maintain the follow-up of subsequent materials. Summary of the Invention

[0005] To address the shortcomings of existing film extruders mentioned in the background art, this invention provides a special extruder for optical-grade thermoplastic polyurethane elastomer films. It features concentric rotation of the threaded extrusion scraper rollers, the scraper rollers' self-rotation peeling off material adhering to the threads, the insertion of the push rod to agitate the material, the material being broken into a porous "broken" state, reduced adhesion between the porous "broken" material and the screw, and the reciprocating motion of the pulling column to deform the surrounding material. This solves the technical problems mentioned in the background art, such as slow conveying due to material adhering to the screw and slow heating due to the material being far from the heating source.

[0006] The present invention provides the following technical solution: an extruder for optical grade thermoplastic polyurethane elastomer film, comprising an extruder housing for processing materials, wherein the extruder housing is provided with a heating device for heating materials and a drive device for power transmission;

[0007] The extruder housing has a processing cavity inside to provide space for material processing. A screw is movably sleeved inside the processing cavity to propel the material forward continuously.

[0008] The inner wall of the processing cavity is provided with evenly distributed rotating grooves, and the rotating grooves are provided with interconnected cavities for air circulation and to maintain the transmission of air pressure changes.

[0009] The inner wall of the processing cavity is provided with a pulling device for pulling the material to deform towards the inner wall of the processing cavity;

[0010] A scraping device is provided at the port of the rotating groove to peel off the material adhering to the screw.

[0011] The scraping device is equipped with a breaking device to break the integrity of the material.

[0012] Preferably, the pulling device includes receiving holes evenly distributed on the inner wall of the processing cavity, a pulling column is movably sleeved in the receiving hole, a reciprocating spring I is fixedly connected to one end of the pulling column facing the communicating cavity, and the other end of the reciprocating spring I is fixedly connected to the inner wall of the communicating cavity, for driving the pulling column to reciprocate, impacting, adhering to and resetting the surrounding material through pulling deformation.

[0013] Preferably, the cross-section of the receiving hole is stepped, and the vertical cross-section of the pulling column is T-shaped to limit the displacement of the pulling column and prevent it from falling out of the receiving hole. The end of the pulling column facing the inner cavity of the machining cavity has a rounded corner to reduce hard collision with the nearby threads. The surface of the pulling column is uneven to increase the friction with the material and improve the material's ability to adhere to the pulling column.

[0014] Preferably, the scraping device includes an annular seat movably sleeved on the port of the rotating groove, and two symmetrical rotating rods movably sleeved on the annular seat. A drive gear is fixedly connected to the end of the rotating rod facing the rotating groove, and a scraping roller is fixedly connected to the end of the rotating rod facing the screw.

[0015] Preferably, the ring seat is circular, with both ends of the ring seat being stepped, and the port of the rotating groove that connects to the processing cavity is stepped, which is used to restrict the ring seat to rotate concentrically with the screw. The rotating rod is cylindrical, and both ends of the rotating groove are fixedly connected with evenly distributed passive teeth. The driving gear meshes with the adjacent passive teeth, which is used to drive the scraping roller to rotate through the rotating rod.

[0016] Preferably, the scraping roller is hexagonal columnar with rounded corners on its hexagonal sides. One side of the scraping roller is attached to the threaded side of the screw, which is used to peel off the material adhering to the screw thread when the scraping roller rotates.

[0017] Preferably, the breaking device includes a scraping roller and a gas storage cavity inside the rotating rod. The scraping roller has evenly distributed sliding holes. A push rod is movably sleeved in the sliding holes. The end of the push rod facing the screw has a rounded corner. A reciprocating spring II is fixedly connected to the end of the push rod facing the gas storage cavity. The other end of the reciprocating spring II is fixedly connected to the inner wall of the gas storage cavity.

[0018] Preferably, the rotating rod is provided with a vent hole, and the air storage chamber is connected to the rotating groove through the vent hole. The rotating groove, the connecting cavity, and the air storage chamber are filled with air for air pressure exchange between the rotating groove, the connecting cavity, and the air storage chamber.

[0019] The present invention has the following beneficial effects:

[0020] 1. This invention utilizes the screw thread to press against the nearby scraping roller, causing the scraping roller to rotate synchronously with the screw thread. This drives the driving gear to continuously mesh with the driven gear, thereby causing the scraping roller to rotate. This causes the scraping roller to rotate relative to the screw thread, thus scraping the material adhering to the screw thread. This separates the material from the screw thread in the direction of the scraping roller's rotation. The separated material then moves closer to the inner wall of the processing cavity near the scraping roller, reducing the gap between the material and the inner wall of the processing cavity, improving the heating effect of the material in this area, and allowing subsequent materials to be propelled forward with less force by the separated material.

[0021] 2. In this invention, the air in the air storage chamber expands due to heat, and in conjunction with the elastic force of the reciprocating spring II, pushes the top of the push rod out of the sliding hole, allowing the push rod to insert into the material separated by the scraping roller. The push rod rotates synchronously with the rotation of the scraping roller, causing the push rod to agitate the surrounding material, forming multiple irregular cavities and creating a "broken" state. As a result, when the material in this area detaches from the scraping roller and re-adheres to the screw, the increased number of adhesion points between the "broken" porous material and the screw, while reducing the adhesion area, reduces the material's adhesion force.

[0022] 3. This invention uses a scraping roller to drive the rotation of the push rod. When the push rod approaches the thread, it is squeezed by the thread and pressed back into the sliding hole, reducing the space inside the sliding hole. This reduces the overall space of the connected rotating groove, connecting cavity, air storage cavity, and sliding hole. The gas that expands due to heat in these spaces transmits the pressure output from the sliding hole to the pulling column, causing the pulling column to collide with the material and adhere to it. When the push rod protrudes out of the sliding hole again, increasing the space inside the sliding hole, the reciprocating spring I can pull the pulling column back to its original position. At this time, the pulling column pulls the adhered material towards the inner wall of the processing cavity. The material forms a convex deformation at the pulling column, allowing more material to approach the inner wall of the processing cavity for efficient heating.

[0023] 4. The present invention uses the push rod to stir the material to form a "broken" porous material, which reduces the reaction force provided by the material adhesion screw when the pulling column pulls the material upward. This allows the pulling column to pull a larger area of ​​material towards the inner wall of the processing cavity, improving the material heating effect and reducing the stroke length of the melting section. Attached Figure Description

[0024] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0025] Figure 2 This is a schematic diagram of the internal structure of the extruder housing of the present invention;

[0026] Figure 3 This is a schematic diagram showing the position of the scraping roller in this invention;

[0027] Figure 4 This is a schematic diagram of the ring seat structure of the present invention;

[0028] Figure 5 This is a schematic diagram of the three-dimensional structure of the scraping roller of the present invention;

[0029] Figure 6 This is a schematic diagram of the internal structure of the scraping roller of the present invention.

[0030] In the diagram: 1. Extruder housing; 2. Machining cavity; 3. Screw; 4. Rotating groove; 5. Connecting cavity; 501. Receiving hole; 6. Passive gear; 7. Ring seat; 8. Pulling column; 9. Reciprocating spring I; 10. Rotating rod; 11. Driving gear; 12. Scraper roller; 13. Air storage cavity; 131. Vent hole; 14. Sliding hole; 15. Push rod; 16. Reciprocating spring II. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Please see Figures 1 to 3 An extruder for optical-grade thermoplastic polyurethane elastomer films includes an extruder housing 1, on which a conventional heating device is installed to heat the material in a processing cavity 2. The extruder housing 1 has a processing cavity 2, and a screw 3 is movably sleeved within the processing cavity 2. There is a gap between the screw 3 and the inner wall of the processing cavity 2 to meet the requirement that the material filling degree in the melting section is less than one. The screw 3 is driven by a conventional drive device, such as the gearbox of a conventional extruder, to drive the screw 3 to rotate and input pressure to the material.

[0033] See Figures 1 to 3 The inner wall of the machining cavity 2 is provided with evenly distributed rotating grooves 4, and interconnecting cavities 5 are provided between the rotating grooves 4. The inner wall of the machining cavity 2 is also provided with evenly distributed receiving holes 501. The cross-section of the receiving holes 501 is stepped, allowing the T-shaped pulling column 8 to be influenced by the receiving holes 501 without excessive displacement, thus preventing the pulling column 8 from detaching from the receiving holes 501. The machining cavity 2 is connected to the interconnecting cavity 5 through the receiving holes 501. The pulling column 8 is movably sleeved within the receiving holes 501. The vertical cross-section of the pulling column 8 is T-shaped, and the pulling column 8 faces the machining cavity 2. One end of the inner cavity 2 is rounded, so that when the screw 3 rotates, the tip of the thread gradually contacts the pulling column 8, which can smoothly squeeze the pulling column 8 and reduce the damage caused by hard collision. The surface of the pulling column 8 is uneven, so that when the pulling column 8 is inserted into the material, the uneven surface can increase the friction with the material and improve the adhesion of the material, so that the pulling column 8 can pull more material to deform. A reciprocating spring I9 is ​​fixedly connected to one end of the pulling column 8 facing the connecting cavity 5, and the other end of the reciprocating spring I9 is ​​fixedly connected to the inner wall of the connecting cavity 5.

[0034] See Figures 1 to 4A ring seat 7 is movably sleeved at one end of the rotating groove 4 that connects to the processing inner cavity 2. The ring seat 7 is circular, and both ends of the ring seat 7 are stepped. The stepped end of the rotating groove 4 that connects to the processing inner cavity 2 restricts the ring seat 7 to only rotate. Two symmetrical rotating rods 10 are movably sleeved on the ring seat 7. The rotating rods 10 are cylindrical. A drive gear 11 is fixedly connected to one end of the rotating rod 10 that faces the rotating groove 4. Both ends of the rotating groove 4 are fixedly connected to evenly distributed passive teeth 6. The drive gear 11 meshes with the adjacent passive teeth 6, so that when the ring seat 7 rotates concentrically with the screw 3, it can drive the drive gear 11 to rotate synchronously through the rotating rods 10. The drive gear 11 continuously meshes with the passive teeth 6 and rotates, causing the drive gear 11 to drive the rotating rod 10 and the scraping roller 12 to rotate.

[0035] See Figure 1 , Figures 3 to 6A scraping roller 12 is fixedly connected to one end of the rotating rod 10 opposite the screw 3. The scraping roller 12 is hexagonal in shape, with rounded corners on its hexagonal sides. One side of the scraping roller 12 is attached to the threaded side of the screw 3. As the scraping roller 12 rotates, multiple sides of the scraping roller 12 continuously move relative to the attached threaded side. When the scraping roller 12 rotates away from the threaded side, the material adhering to the threaded side is peeled off by the shearing force of the scraping roller 12 side, thus removing the material from the threaded side. The material separates and continues to move forward under the influence of subsequent materials, passing over the scraping roller 12. Driven by the rotation of the scraping roller 12, the material protrudes towards the inner wall of the processing cavity 2, reducing the gap between the material and the inner wall of the processing cavity 2. Both the scraping roller 12 and the rotating rod 10 have air storage chambers 13, and the rotating rod 10 has ventilation holes 131. The air storage chambers 13 are connected to the rotating groove 4 through the ventilation holes 131, allowing pressure changes within the air storage chambers 13 or the rotating groove 4 to be transmitted between them through the ventilation holes 131. The scraping roller 12 has evenly distributed sliding holes 1. 4. A push rod 15 is movably sleeved inside the sliding hole 14. The end of the push rod 15 facing the screw 3 has a rounded corner. A reciprocating spring II 16 is fixedly connected to the end of the push rod 15 facing the air storage chamber 13. The other end of the reciprocating spring II 16 is fixedly connected to the inner wall of the air storage chamber 13. When the scraping roller 12 rotates, causing the push rod 15 to gradually move away from the fitted thread, the compressed reciprocating spring II 16 and the air pressure will push the top of the push rod 15 out of the sliding hole 14, causing the push rod 15 to insert into the stripped material. At this time, the subsequent material still pushes the material in this area forward. As the push rod 15 continues to rotate following the rotation of the scraping roller 12, a relative displacement occurs between the push rod 15 and the advancing material, causing the push rod 15 to agitate the material and form a "broken" irregular shape with multiple holes. At the same time, when the push rod 15 presses into the sliding hole 14, the space of the sliding hole 14 becomes smaller, and the push rod 15 transmits pressure through the gas in the gas storage chamber 13, the vent hole 131, the rotating groove 4, and the connecting chamber 5 to the pulling column 8, causing the pulling column 8 to collide with the material in the processing inner cavity 2 and insert the pulling column 8 into the material.

[0036] The rotating groove 4, the connecting cavity 5, and the air storage cavity 13 are filled with air.

[0037] The method of using (working principle) of this invention is as follows:

[0038] First, when the material enters the melting section, it adheres to the screw 3. A gap exists between the screw 3 and the inner wall of the processing cavity 2, and the material itself also has a gap. The screw 3 propels the softened, paste-like material forward. Subsequent material also moves forward under the influence of the screw 3. Meanwhile, the heating device inside the extruder housing 1 continuously heats the material. The rotation of the screw 3 causes the threads on it to press against the nearby scraper roller 12, causing the scraper roller 12 to drive the ring seat 7 to rotate concentrically with the screw 3. At this time, the ring seat 7 drives the drive gear 11 to rotate synchronously via the rotating rod 10, causing the drive gear 11 to rotate synchronously. Gear 11 continuously meshes with the approaching passive gear 6, causing the driving gear 11 to rotate. This rotation is then driven by the rotating rod 10 to rotate the scraping roller 12, causing the scraping roller 12 to move relative to the thread. Taking one side of the scraping roller 12 as an example, as the scraping roller 12 rotates, this side gradually separates from the thread. When rotating away from the thread, this side scrapes the material that is close to it from the thread and lifts the material that has been separated from the thread away from the thread. This causes the material around the scraping roller 12 to bulge and deform, and move closer to the inner wall of the processing cavity 2, so that the heating device inside the extruder housing 1 heats the material that is close to it.

[0039] Then, the high temperature will cause the air in the rotating groove 4, connecting cavity 5, air storage cavity 13, and vent hole 131 to absorb heat and expand, and the air pressure will continue to increase. At this time, when the scraping roller 12 rotates, causing the push rod 15 to gradually move away from the fitted thread, the compressed reciprocating spring II 16 and the air pressure will push the top of the push rod 15 out of the sliding hole 14, so that the push rod 15 is inserted into the stripped material. At this time, the subsequent material still pushes the material here forward. Then, the push rod 15 continues to rotate with the rotation of the scraping roller 12, so that the push rod 15 and the forward material are relatively displaced, so that the push rod 15 agitates the material, making the material here form a "broken" irregular shape with multiple holes. Then, when the scraping roller 12 continues to rotate, the material here will continue to rotate. As the rotation continues, the push rod 15 gradually approaches the thread, causing its top to contact the thread. The push rod 15 is then pressed into the sliding hole 14 by the thread's pressure. During this process, the porous, broken material continues to advance, gradually moving away from the scraper roller 12 and contacting the screw 3 again. This causes the porous, broken material to adhere to the screw 3. At this point, the porous material adheres to the screw 3 in a multi-point pattern, rather than a planar pattern. Next, the push rod 15 is pressed into the sliding hole 14, reducing the space within the hole. This allows the push rod 15 to transmit pressure through the expanding gas in the gas storage chamber 13, vent hole 131, rotating groove 4, and connecting chamber 5 to the pulling force. The screw 8 is pulled into the material inside the processing cavity 2 by the screw 3, causing it to penetrate the material. At this point, the material adheres to the screw 8 under the pressure of the screw 3 and the uneven surface of the screw 8. Simultaneously, the reciprocating spring I9 is ​​stretched. Then, when the push rod 15 protrudes again from the sliding hole 14, the space in the sliding hole 14 increases, reducing the air pressure on the screw 8. This causes the reciprocating spring I9 to pull the screw 8 back to its original position, causing the screw 8 to pull the adhered material towards the inner wall of the processing cavity 2. At this point, the adhesion force of the porous material to the screw 3 decreases, reducing the resistance provided by the adhesion force of the material to the screw 3. The resistance of the material to the scraping roller 12 decreases, allowing the pulling column 8 to pull more material toward the inner wall of the processing cavity 2. At the same time, the pulled material gets closer to the inner wall of the processing cavity 2, which continuously reduces the gap between the material and the inner wall of the processing cavity 2, shortens the heating distance, and improves the heating effect on the material here, until the pulling force provided by the pulling column 8 is equal to the resistance provided by the material. During this process, the material continues to move forward under the drive of the screw 3, causing the material adhering to the pulling column to gradually break off from the adhesion of the pulling column 8, causing the pulling column 8 to lose the adhering material and retract into the storage hole 501. At the same time, the pulling column 8 will also be squeezed by the top of the rotating screw and pressed into the storage hole 501.

[0040] Finally, the screw 3 rotates continuously, driving the scraping roller 12 to rotate concentrically, so that the scraping roller 12 maintains the above-mentioned movement, and can peel, crush and pull the subsequent materials.

Claims

1. An optical grade thermoplastic polyurethane elastomer film dedicated extruder characterized by: It includes an extruder housing (1) for processing materials, and a processing cavity (2) is provided inside the extruder housing (1) to provide space for material processing. A screw (3) is movably sleeved inside the processing cavity (2) to push the material forward continuously. The inner wall of the processing cavity (2) is provided with evenly distributed rotating grooves (4), and the rotating grooves (4) are provided with interconnected cavities (5) for air circulation and to maintain the transmission of air pressure changes. The inner wall of the processing cavity (2) is provided with a pulling device for pulling the material to deform towards the inner wall of the processing cavity (2); The rotating groove (4) is provided with a scraping device at its port for peeling off the material adhering to the screw (3); The scraping device is equipped with a breaking device to break the integrity of the material; The scraping device includes a ring seat (7) movably sleeved on the port of the rotating groove (4). Two symmetrical rotating rods (10) are movably sleeved on the ring seat (7). A drive gear (11) is fixedly connected to one end of the rotating rod (10) facing the rotating groove (4). A scraping roller (12) is fixedly connected to one end of the rotating rod (10) facing the screw (3). The ring seat (7) is circular, and the two ends of the ring seat (7) are stepped. The port of the rotating groove (4) connected to the processing cavity (2) is stepped, which is used to restrict the ring seat (7) to rotate concentrically with the screw (3). The rotating rod (10) is cylindrical. Both ends of the rotating groove (4) are fixedly connected with evenly distributed passive teeth (6). The driving gear (11) meshes with the adjacent passive teeth (6), which is used for the driving gear (11) to drive the scraping roller (12) to rotate through the rotating rod (10). The destruction device includes a scraping roller (12) and a gas storage chamber (13) opened inside the rotating rod (10). The scraping roller (12) has evenly distributed sliding holes (14). A push rod (15) is movably sleeved in the sliding hole (14). The end of the push rod (15) facing the screw (3) has a rounded corner. A reciprocating spring II (16) is fixedly connected to the end of the push rod (15) facing the gas storage chamber (13). The other end of the reciprocating spring II (16) is fixedly connected to the inner wall of the gas storage chamber (13).

2. The extruder for optical grade thermoplastic polyurethane elastomer film according to claim 1, characterized in that: The pulling device includes a collection hole (501) evenly distributed on the inner wall of the processing cavity (2). A pulling column (8) is movably sleeved in the collection hole (501). A reciprocating spring I (9) is fixedly connected to one end of the pulling column (8) facing the connecting cavity (5). The other end of the reciprocating spring I (9) is fixedly connected to the inner wall of the connecting cavity (5) to drive the pulling column (8) to reciprocate, impacting, adhering to, and resetting the surrounding material through pulling deformation.

3. The extruder for optical grade thermoplastic polyurethane elastomer film according to claim 2, characterized in that: The cross-section of the receiving hole (501) is stepped, and the vertical cross-section of the pulling column (8) is T-shaped, which is used to limit the displacement of the pulling column (8) and prevent it from falling out of the receiving hole (501). The end of the pulling column (8) facing the processing inner cavity (2) has rounded corners to reduce hard collisions with the nearby threads. The surface of the pulling column (8) is uneven to increase the friction with the material and improve the material's ability to adhere to the pulling column (8).

4. The extruder for optical grade thermoplastic polyurethane elastomer film according to claim 1, characterized in that: The scraping roller (12) is hexagonal columnar with rounded corners on its hexagonal side. One side of the scraping roller (12) is attached to the threaded side of the screw (3) for the scraping roller (12) to peel off the material adhering to the thread of the screw (3) when it rotates.

5. The extruder for optical grade thermoplastic polyurethane elastomer film according to claim 1, characterized in that: The rotating rod (10) is provided with a vent hole (131). The air storage chamber (13) is connected to the rotating groove (4) through the vent hole (131). The rotating groove (4), the connecting chamber (5), and the air storage chamber (13) are filled with air for the air pressure exchange between the rotating groove (4), the connecting chamber (5), and the air storage chamber (13).

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