Twin-screw extruder for blow-molded packaging film preparation

Abstract

This invention discloses a twin-screw extruder for preparing blow-molded packaging films, relating to the field of blow-molded packaging film extrusion technology. It includes a frame, and further includes a drive mechanism and a stirring assembly mounted on the top of the frame. The stirring assembly has two symmetrically rotating components connected to its outer periphery. A heating device is activated to heat and plasticize the material. As the stirring rods continue to rotate, they perform rotational shearing on the plasticized material, achieving mixing. The main gear connected to the outer periphery of the stirring rods rotates synchronously, driving the meshing secondary gear, causing the rotating shaft connected to the secondary gear to rotate within the connecting cylinder. The rotating blades on the outer periphery of the rotating shaft also efficiently stir the plasticized material. Notably, the stirring rods and rotating blades rotate in opposite directions. This stirring method not only enhances the stirring effect but also increases the shearing force on the material, more effectively reducing air bubbles in the material and improving material quality.

Description

Technical Field

[0001] This invention relates to the field of blow-molded packaging film extrusion technology, and more particularly to a twin-screw extruder for the preparation of blow-molded packaging films. Background Technology

[0002] Twin-screw extruders are widely used in the plastics processing industry. Their core working principle is to effectively mix, plasticize, and transport materials through two precisely meshing screws. They play a crucial role, especially in the preparation of blow-molded packaging films. However, in actual production, air bubbles may occur inside the equipment, which is a phenomenon that must be taken very seriously.

[0003] Twin-screw extruders rely on the coordinated rotation of two screws to propel the material forward. Simultaneously, external heating devices and the shear and frictional heat generated during screw rotation are used to fully plasticize the material. However, if the extrusion pressure fluctuates during plasticization, it can lead to uneven extrusion volume, resulting in bubbles on the surface of the produced film. Furthermore, if the screw speed is set too high, excessive friction during extrusion can generate excessive heat, which is also a significant factor in inducing bubble formation.

[0004] Besides screw speed, controlling the material extrusion speed is equally crucial. Extrusion speed that is too fast or too slow can cause unstable material flow during the extrusion process, leading to the formation of bubbles. At the same time, unstable internal temperature of the extruder is also an important reason for bubble formation. Temperature fluctuations may cause uneven heating of the material during the extrusion process, resulting in insufficient plasticization of some materials and ultimately leaving bubbles on the film surface. Summary of the Invention

[0005] The purpose of this invention is to address the problem that fluctuations in extrusion pressure during the plasticizing process lead to uneven extrusion volume, resulting in bubbles on the surface of the finished film. Furthermore, excessively high screw speeds cause excessive heat generation due to friction during extrusion, another significant factor contributing to bubble formation. Besides screw speed, controlling the material extrusion speed is equally crucial; excessively fast or slow speeds can cause unstable material flow, leading to bubble formation. Instability in the extruder's internal temperature is also a major cause of bubble formation; temperature fluctuations can result in uneven heating of the material during extrusion, leading to incomplete plasticization and ultimately leaving bubbles on the film surface. Therefore, this invention proposes a solution to address these issues.

[0006] To achieve the above objectives, the present invention employs the following technical solution for a twin-screw extruder used in the preparation of blow-molded packaging films: including a frame, and further including a drive mechanism and a stirring assembly mounted on the top of the frame, wherein the outer periphery of the stirring assembly is connected to two symmetrically rotating components; The rotating assembly includes a connecting cylinder connected to the outer periphery of the stirring assembly, and a main gear sleeved on the outer periphery of the stirring assembly. A rotating shaft is rotatably connected to the inner wall of the connecting cylinder. A connecting plate and a limiting block are respectively connected to both ends of the rotating shaft. A sealing gasket is connected between the outer periphery of the rotating shaft and the connecting cylinder. A rotating blade is connected to the outer periphery of the rotating shaft, and a secondary gear is connected to the outer periphery of the rotating shaft through a sliding member. One side of the secondary gear is rotatably connected to the stirring assembly through a rotating plate. The main gear and the secondary gear are meshed. A stop component is connected to one side of the secondary gear. The stirring assembly is driven to rotate by the drive mechanism. While the stirring assembly is rotating, the main gear drives the auxiliary gear to drive the rotating shaft to rotate. As the rotating shaft rotates, the rotating blades stir the plastic solution in the stirring assembly. At the same time, the rotating blades move back and forth by the pushing of the pushing assembly, squeezing out the air bubbles in the solution.

[0007] As a further description of the above technical solution: The sliding component includes several grooves formed on the outer periphery of the rotating shaft, and the inner ring of the auxiliary gear is connected to a slider that is slidably connected to the grooves.

[0008] As a further description of the above technical solution: The abutting component includes an abutting rod fixedly connected to one side of the limiting block, a contact block connected to the outer periphery of the stirring component, and the abutting rod in contact with the contact block. A protrusion is connected to one side of the contact block, and a groove that is far away from the protrusion is opened inside the contact block. An elastic element is connected to one side of the connecting plate.

[0009] As a further description of the above technical solution: The elastic element includes several movable grooves formed inside the auxiliary gear, and a fixed rod that is slidably connected to the movable groove is fixedly connected to one side of the connecting plate. Each fixed rod is fitted with a telescopic spring on its outer periphery.

[0010] As a further description of the above technical solution: The rotating blade is equipped with a piercing component, which includes several slots opened inside the rotating blade. Each slot has a fixed post fixedly connected to its inner wall, and a rotating sleeve is rotatably connected to the outer periphery of the fixed post.

[0011] As a further description of the above technical solution: The piercing assembly also includes several piercing heads connected to both sides of the slot.

[0012] As a further description of the above technical solution: The height and length of several of the piercing heads are aligned with the curvature of the rotating sleeve.

[0013] As a further description of the above technical solution: The mixing assembly includes a mixing tank connected inside the frame body. Two mixing rods are rotatably connected inside the mixing tank. A discharge port is opened on the outer periphery of the mixing tank. The two mixing rods are connected to the drive mechanism through a connecting shaft on one side. An extrusion port is opened on the side of the mixing tank away from the connecting shaft.

[0014] As a further description of the above technical solution: The drive mechanism includes a motor connected to one side of the frame, and an output shaft is connected to one side of the motor.

[0015] As a further description of the above technical solution: The frame includes a base frame, and a support frame is fixedly connected to the top of the base frame.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: When operating the equipment, first add the material into the mixing tank through the feed port, then start the motor. The output shaft of the motor starts to rotate, driving the two connecting shafts to rotate in opposite directions, which in turn drives the mixing rod to push the material to move inside the mixing tank. At the same time, the heating device is activated to heat and plasticize the material. As the stirring rods continue to rotate, they rotate and shear the plasticized material to achieve mixing. The main gear connected to the outer circumference of the stirring rods rotates synchronously, driving the secondary gear meshing with it, so that the rotating shaft connected to the secondary gear rotates in the connecting cylinder. The rotating blades on the outer circumference of the rotating shaft also efficiently stir the plasticized material. It is worth noting that the stirring rods and the rotating blades rotate in opposite directions. This stirring method not only enhances the stirring effect but also increases the shearing force on the material, more effectively reducing air bubbles in the material and improving the material quality. In addition, the rotation of the secondary gear drives the rotating shaft to rotate together, and the abutment rod connected to the limiting block on one side of the rotating shaft also rotates. When the abutment rod contacts the protrusion and groove on the contact block, it pushes or pulls the rotating shaft to move, so that the rotating shaft moves back and forth within a certain range while following the rotation of the secondary gear. This back and forth movement drives the rotating blades to move back and forth between the blades of the stirring rod, squeezing the material and further reducing the air bubbles in the material. As the rotating blades rotate and reciprocate, the plasticized material exhibits two flow patterns: one part of the material moves along the space between the stirring rod and the rotating blades, while the other part enters the groove under the push of the rotating blades. This continuous pushing flow generates sufficient power to drive the rotating sleeve to rotate, further enhancing the mixing effect of the material in the groove. At the same time, the piercing head further treats the air bubbles in the material flowing in the groove, significantly reducing the air bubble problem in the material. Attached Figure Description

[0017] Figure 1 A schematic diagram of the overall structure according to the present invention is shown; Figure 2 A schematic diagram of the internal structure of the mixing tank according to the present invention is shown; Figure 3 A schematic diagram of the stirring rod structure according to the present invention is shown; Figure 4 A schematic diagram of the rotating component structure according to the present invention is shown; Figure 5 A schematic diagram of the abutment component structure according to the present invention is shown; Figure 6 A schematic diagram of the rotating blade structure according to the present invention is shown; Figure 7 The present invention is shown Figure 6 Enlarged view of a portion of point A in the middle; Figure 8 A schematic diagram of the fixed column structure according to the present invention is shown; Figure 9 A schematic diagram of the motion trajectory of the stirring rod and rotating blades according to the present invention is shown.

[0018] Legend: 10. Frame; 11. Base frame; 12. Support frame; 20. Drive mechanism; 21. Motor; 22. Output shaft; 30. Mixing assembly; 31. Mixing tank; 32. Feed inlet; 33. Extrusion outlet; 34. Connecting shaft; 35. Mixing rod; 40. Rotating assembly; 41. Connecting cylinder; 42. Main gear; 43. Rotating shaft; 431. Slide groove; 44. Secondary gear; 441. Slider; 45. Connecting plate; 46. Limiting block; 47. Rotating blade; 48. Rotating plate; 49. Sealing gasket; 50. Abutment assembly; 51. Abutment rod; 52. Contact block; 521. Protrusion; 522. Groove; 53. Fixing rod; 531. Moving groove; 54. Telescopic spring; 60. Puncture component; 61. Groove; 62. Fixing post; 63. Rotating sleeve; 64. Puncture head. Detailed Implementation

[0019] 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.

[0020] like Figures 1-9 As shown, the twin-screw extruder for preparing blow-molded packaging film provided by the present invention includes a frame 10, the frame 10 includes a base frame 11, a support frame 12 is fixedly connected to the top of the base frame 11, and further includes a drive mechanism 20 and a stirring assembly 30 assembled on the top of the support frame 12. The drive mechanism 20 includes a motor 21 connected to one side of the support frame 12, and an output shaft 22 is connected to one side of the motor 21.

[0021] like Figure 1 , Figure 2 , Figure 3 As shown, the mixing assembly 30 includes a mixing tank 31 connected inside the support frame 12. A heating device is installed on the outer periphery of the mixing tank 31. Two mixing rods 35 are rotatably connected inside the mixing tank 31. A discharge port 32 is opened on the outer periphery of the mixing tank 31. The two mixing rods 35 are connected to the output shaft 22 through a connecting shaft 34 on one side. An extrusion port 33 is opened on the side of the mixing tank 31 away from the connecting shaft 34. During operation, the material is first added into the mixing tank 31 through the feed port 32. Then, the motor 21 is started, which drives its output shaft 22 to start rotating. As the output shaft 22 rotates, the two connecting shafts 34 are driven to rotate in opposite directions. The rotation of the two connecting shafts 34 in turn drives the stirring rod 35 to move, and the stirring rod 35 pushes the material to move in the mixing tank 31. While the material is moving, the heating device is activated to complete the heating and plasticizing process of the material. At the same time, as the stirring rods 35 continue to rotate, they will rotate and shear the plasticized material, thereby realizing the stirring and mixing of the plasticized material by the stirring rods 35. Finally, the material, after being plasticized and mixed, will flow smoothly out through the extrusion port 33 under the push of the stirring rod 35, completing the entire operation process.

[0022] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6As shown, two symmetrical rotating components 40 are connected to the outer periphery of the mixing tank 31. The rotating component 40 includes a connecting cylinder 41 connected to the outer periphery of the mixing tank 31 and a main gear 42 sleeved on the outer periphery of the stirring rod 35. A rotating shaft 43 is rotatably connected to the inner wall of the connecting cylinder 41. A connecting plate 45 and a limiting block 46 are respectively connected to the two ends of the rotating shaft 43. A sealing gasket 49 is connected between the outer periphery of the rotating shaft 43 and the connecting cylinder 41. A rotating blade 47 is connected to the outer periphery of the rotating shaft 43. Each blade of the rotating blade 47 is arranged between the blades of the stirring rod 35. A secondary gear 44 is connected to the outer periphery of the rotating shaft 43 through a sliding member. The sliding member includes several grooves 431 opened on the outer periphery of the rotating shaft 43. A slider 441 that is slidably connected to the grooves 431 is connected to the inner ring of the secondary gear 44. One side of the secondary gear 44 is rotatably connected to the mixing tank 31 through a rotating plate 48. The main gear 42 and the secondary gear 44 are meshed. A push component 50 is connected to one side of the secondary gear 44. As the stirring rod 35 rotates, the main gear 42 connected to its outer circumference also rotates synchronously. During the rotation of the main gear 42, it further drives the secondary gear 44 meshing with it, causing the rotating shaft 43 connected to the secondary gear 44 to start rotating inside the connecting cylinder 41. During the rotation of the rotating shaft 43, the rotating blades 47 installed on its outer circumference also efficiently stir the plasticized material. It is worth noting that the rotation directions of the stirring rod 35 and the rotating blades 47 are opposite. This relative rotation stirring method can not only enhance the stirring effect on the plasticized material, but also increase the shear force on the plasticized material, thereby more effectively reducing the air bubbles present in the plasticized material and improving the quality of the material.

[0023] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, the abutting assembly 50 includes an abutting rod 51 fixedly connected to one side of the limiting block 46. A contact block 52 is connected to the outer periphery of the mixing tank 31, and the abutting rod 51 is in contact with the contact block 52. A protrusion 521 is connected to one side of the contact block 52. A groove 522 that is far away from the protrusion 521 is opened inside the contact block 52. An elastic element is connected to one side of the connecting plate 45. The elastic element includes several moving grooves 531 opened inside the auxiliary gear 44. A fixed rod 53 that is slidably connected to the moving grooves 531 is fixedly connected to one side of the connecting plate 45. A telescopic spring 54 is sleeved on the outer periphery of each fixed rod 53. The two ends of the telescopic spring 54 are fixedly connected to the connecting plate 45 and the auxiliary gear 44, respectively. As the secondary gear 44 rotates, it drives the rotating shaft 43 to rotate as well. During this process, the abutment rod 51 connected to the limiting block 46 on one side of the rotating shaft 43 also rotates. Since the abutment rod 51 always remains in contact with the contact block 52, the telescopic spring 54 is always in a stretched state. During the rotation of the abutment rod 51, it will come into contact with the protrusion 521 and the groove 522 on the contact block 52. When the abutment rod 51 contacts the protrusion 521, it will push the limit block 46 and its connected rotating shaft 43 to move, causing the connecting plate 45 on one side of the rotating shaft 43 to move away from the secondary gear 44. At the same time, this movement also causes the fixed rod 53 to slide in the moving groove 531 inside the secondary gear 44 and further stretch the telescopic spring 54. When the abutment rod 51 contacts the groove 522, since one end of the telescopic spring 54 is fixedly connected to the auxiliary gear 44, the spring will rebound and pull the connecting plate 45 to move. This movement causes the connecting plate 45 to push the rotating shaft 43 to move together. Therefore, while the rotating shaft 43 rotates with the auxiliary gear 44, it will also reciprocate within a certain range. This reciprocating movement causes the rotating blades 47 to reciprocate between the blades of the stirring rod 35. In this way, the rotating blades 47 not only stir the plasticized material, but also squeeze the plasticized material in the pushing state. By squeezing back and forth by the rotating blades 47, the air bubbles present in the plasticized material can be further reduced. Meanwhile, as the rotating blade 47 moves back and forth, the space between the stirring rod 35 and the rotating blade 47 also changes. This causes the plastic material to exhibit speed changes depending on the size of the space during the pushing process. When the space is small, the pushing of the plastic material can be further accelerated. This pushing method of varying speed also helps to reduce possible sticking problems.

[0024] like Figure 1 , Figure 2 , Figure 4 , Figure 6 , Figure 7 , Figure 8 As shown, a piercing assembly 60 is installed inside the rotating blade 47. The piercing assembly 60 includes several slots 61 opened inside the rotating blade 47. A fixing post 62 is fixedly connected between the inner walls of each slot 61. A rotating sleeve plate 63 is rotatably connected to the outer periphery of the fixing post 62. The piercing assembly 60 also includes several piercing heads 64 connected to both sides of the slots 61. The height and length of the several piercing heads 64 are fitted to the curvature of the rotating sleeve plate 63. As the rotating blade 47 rotates, it moves back and forth between the blades of the stirring rod 35. This action causes the plasticized material to have two flow patterns: part of the plasticized material moves along the space between the stirring rod 35 and the rotating blade 47, while the other part of the plasticized material is effectively guided into the groove 61 by the back-and-forth pushing force of the rotating blade 47. Because the plasticized material is in this continuous pushing flow state, it generates enough power to drive the rotating sleeve 63 to rotate together. The rotation of the rotating sleeve 63 further enhances the mixing effect of the plasticized material in the groove 61. Meanwhile, as the rotating sleeve 63 rotates and moves, the plasticized material continues to flow along the space between the rotating sleeve 63 and the puncturing head 64. In this process, the puncturing head 64 plays a key role. It can further process the air bubbles in the plasticized material flowing in the slot 61, thereby greatly reducing the air bubble problem in the plasticized material. This design not only improves the mixing efficiency of the plasticized material, but also significantly improves its quality.

[0025] Working principle: First, the material is added into the mixing tank 31 through the feed port 32. Then, the motor 21 is started, and the motor 21 drives the output shaft 22 to rotate, which drives the two connecting shafts 34 to rotate in opposite directions, thereby driving the stirring rod 35 to move the material. At the same time, the heating device is started to heat and plasticize the material. The stirring rod 35 continues to rotate, performing rotational shearing and mixing on the plasticized material. The outer peripheral main gear 42 of the stirring rod 35 rotates synchronously, driving the meshing secondary gear 44, so that the connected rotating shaft 43 rotates in the connecting tank 41. The rotating blades 47 on the rotating shaft 43 perform efficient mixing on the material. The relative rotation of the stirring rod 35 and the rotating blades 47 enhances the mixing effect and shearing force, effectively reduces bubbles, and improves the quality of the material. The rotation of the secondary gear 44 drives the rotating shaft 43 and the abutment rod 51 connected to the limiting block 46 to rotate. The abutment rod 51 contacts the protrusion 521 and groove 522 on the contact block 52, producing movement and rebound, causing the rotating shaft 43 to move back and forth within a certain range. This back and forth movement causes the rotating blade 47 to also move back and forth between the blades of the stirring rod 35, stirring and squeezing the material, further reducing air bubbles. The rotation and reciprocating movement of the rotating blade 47 cause the plasticized material to produce two flow patterns. Part of the material moves along the space between the stirring rod 35 and the rotating blade 47, while the other part of the material is pushed into the slot 61 by the rotating blade 47. The continuous flow of the material drives the rotating sleeve 63 to rotate, which enhances the mixing effect of the material in the slot 61. At the same time, the rotating sleeve 63 and the piercing head 64 further process the material, significantly reducing the bubble problem and improving the mixing efficiency and quality.

[0026] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A twin-screw extruder for preparing blow-molded packaging films, comprising a frame (10), characterized in that, Also includes: The drive mechanism (20) and the stirring assembly (30) are mounted on the top of the frame (10). The outer periphery of the stirring assembly (30) is connected to two symmetrical rotating components (40). The rotating assembly (40) includes a connecting cylinder (41) connected to the outer periphery of the stirring assembly (30) and a main gear (42) sleeved on the outer periphery of the stirring assembly (30). A rotating shaft (43) is rotatably connected to the inner wall of the connecting cylinder (41). A connecting plate (45) and a limiting block (46) are respectively connected to both ends of the rotating shaft (43). A sealing gasket (49) is connected between the outer periphery of the rotating shaft (43) and the connecting cylinder (41). A rotating blade (47) is connected to the outer periphery of the rotating shaft (43). A secondary gear (44) is connected to the outer periphery of the rotating shaft (43) through a sliding member. One side of the secondary gear (44) is rotatably connected to the stirring assembly (30) through a rotating plate (48). The main gear (42) and the secondary gear (44) are meshed. A pusher assembly (50) is connected to one side of the secondary gear (44). The stirring assembly (30) is driven to rotate by the driving mechanism (20). While the stirring assembly (30) is rotating, the main gear (42) drives the auxiliary gear (44) to drive the rotating shaft (43) to rotate. As the rotating shaft (43) rotates, the rotating blades (47) stir the plastic solution in the stirring assembly (30). At the same time, the rotating blades (47) move back and forth by the abutting assembly (50) to squeeze the air bubbles in the solution. The rotating blade (47) is equipped with a piercing assembly (60). The piercing assembly (60) includes several slots (61) opened inside the rotating blade (47). A fixed column (62) is fixedly connected between the inner walls of each slot (61). A rotating sleeve plate (63) is rotatably connected to the outer periphery of the fixed column (62). The piercing assembly (60) also includes a plurality of piercing heads (64) connected to both sides of the slot (61). The height and length of several of the piercing heads (64) are aligned with the curvature of the rotating sleeve (63).

2. The twin-screw extruder for preparing blow-molded packaging films according to claim 1, characterized in that, The sliding member includes several grooves (431) formed on the outer periphery of the rotating shaft (43), and the inner ring of the auxiliary gear (44) is connected to a slider (441) that is slidably connected to the grooves (431).

3. The twin-screw extruder for preparing blow-molded packaging films according to claim 1, characterized in that, The abutting component (50) includes an abutting rod (51) fixedly connected to one side of the limiting block (46), a contact block (52) is connected to the outer periphery of the stirring component (30), and the abutting rod (51) is in contact with the contact block (52). A protrusion (521) is connected to one side of the contact block (52), and a groove (522) that is far away from the protrusion (521) is opened inside the contact block (52). An elastic element is connected to one side of the connecting plate (45).

4. The twin-screw extruder for preparing blow-molded packaging films according to claim 3, characterized in that, The elastic element includes several movable grooves (531) opened inside the auxiliary gear (44), and a fixed rod (53) that is slidably connected to the movable groove (531) is fixedly connected to one side of the connecting plate (45). Each fixed rod (53) is fitted with a telescopic spring (54) on its outer periphery.

5. The twin-screw extruder for preparing blow-molded packaging films according to claim 1, characterized in that, The mixing assembly (30) includes a mixing tank (31) connected inside the frame (10). Two mixing rods (35) are rotatably connected inside the mixing tank (31). A discharge port (32) is opened on the outer periphery of the mixing tank (31). The two mixing rods (35) are connected to the drive mechanism (20) through a connecting shaft (34) on one side. An extrusion port (33) is opened on the side of the mixing tank (31) away from the connecting shaft (34).

6. The twin-screw extruder for preparing blow-molded packaging films according to claim 1, characterized in that, The drive mechanism (20) includes a motor (21) connected to one side of the frame (10), and an output shaft (22) is connected to one side of the motor (21).

7. The twin-screw extruder for preparing blow-molded packaging films according to claim 1, characterized in that, The frame (10) includes a base frame (11), and a support frame (12) is fixedly connected to the top of the base frame (11).

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