A stretching device for TPU film

Abstract

This utility model discloses a stretching device for TPU film, relating to the field of TPU film processing. It includes a stretching box and stretching mechanisms embedded at both ends of the stretching box. Each stretching mechanism comprises two symmetrically arranged stretching cylinders, with a differential speed assembly between them. Both ends of the stretching cylinders are fixed with drive shafts rotatably inserted into the stretching box. A heating chamber is welded to one end of the stretching box, and a heat-insulating flow channel is welded to the other end. This utility model heats the TPU film body between the two stretching mechanisms through heat convection generated by a fan and heating rod in the heating chamber. The hot airflow flows from both sides of the TPU film body, preventing uneven temperature distribution and reducing misalignment during stretching. The stretched TPU film body is then subjected to heat annealing treatment, further reducing the stress generated after stretching.

Description

Technical Field

[0001] This utility model relates to the field of TPU film processing, specifically a stretching device for TPU films. Background Technology

[0002] The stretching device for TPU (thermoplastic polyurethane) film is a key piece of equipment used in the production process to orient and stretch the film to improve its mechanical properties, dimensional stability and optical properties.

[0003] Currently, existing TPU film unidirectional stretching equipment uses the speed difference between two sets of stretching cylinders to achieve stretching, and uses a heating device embedded in the stretching cylinder to heat the TPU film. However, because the heating device is installed in the stretching cylinder, the side of the TPU film in contact with the stretching cylinder will be hotter than the other side, which can easily cause misalignment during the stretching process. In addition, there is a lack of annealing treatment for the stretched TPU film. Utility Model Content

[0004] Based on this, the purpose of this utility model is to provide a stretching device for TPU film, so as to solve the problem that the side of the TPU film in contact with the stretching cylinder is hotter than the other side due to the heating device installed in the stretching cylinder, which easily leads to misalignment during the stretching process, and the lack of annealing technology for the stretched TPU film.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a stretching device for TPU film, comprising a stretching box and stretching mechanisms embedded at both ends of the stretching box, wherein the stretching mechanism comprises two symmetrically arranged stretching cylinders, and a differential speed assembly is provided between the two stretching mechanisms, wherein both ends of the plurality of stretching cylinders are fixed with drive shafts rotatably inserted into the stretching box, a heating box is welded and fixed at one end of the stretching box, and a heat-insulating flow channel is welded and fixed at the other end of the stretching box.

[0006] The present invention is further configured such that both ends of the stretching box are provided with feeding grooves, and both ends of the stretching box are rotatably mounted with guide rollers, and a TPU film body is provided between the two feeding grooves.

[0007] The present invention is further configured such that a gear is fixedly sleeved at one end of the drive shaft passing through the tension box, and the two gears on the same side are meshed with each other.

[0008] The present invention is further configured such that the differential assembly includes differential wheels fixedly sleeved on two drive shafts and a differential belt meshing between the two differential wheels, wherein the size ratio of the two differential wheels is 2:1.

[0009] The present invention is further configured such that a motor is fixedly installed on the outer wall of the stretching box, and the motor shaft is fixedly connected to the drive shaft.

[0010] The present invention is further configured such that a transparent viewing window is embedded and fixed in the top of the stretching box, and the plurality of heat-insulating and guiding channels are U-shaped and welded and fixed to the outer wall of the stretching box.

[0011] The present invention is further configured such that heating rods and fans are respectively embedded and fixed at both ends of the heating box, and a dustproof net is embedded and fixed on the outer wall of the heating box.

[0012] In summary, this utility model has the following beneficial effects: By welding a heating box to the center of the side wall of the stretching box, the heat convection generated by the fan and heating rod in the heating box heats the TPU film body between the two stretching mechanisms. The hot airflow flows from both sides of the TPU film body, avoiding uneven temperature distribution and reducing misalignment during stretching. Furthermore, by fixing a heat-insulating guide channel to the side wall of the stretching box, part of the hot airflow generated in the heating box heats and anneals the stretched TPU film body along the heat-insulating guide channel, reducing the stress generated after stretching. Simultaneously, another portion of the hot airflow remains in the stretching box to preheat the input TPU film body, improving the stretching effect of the TPU film body. Attached Figure Description

[0013] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0014] Figure 2 This is a schematic diagram of the structure of this utility model from another angle;

[0015] Figure 3 This is a cross-sectional structural diagram of the present invention;

[0016] Figure 4 For the present utility model Figure 3 Enlarged schematic diagram of the structure at point A in the middle.

[0017] In the diagram: 1. Stretching box; 2. Transparent window; 3. Feed chute; 4. Guide roller; 5. Differential wheel; 6. Motor; 7. Differential belt; 8. Insulated flow channel; 9. TPU film body; 10. Drive shaft; 11. Dustproof net; 12. Gear; 13. Stretching cylinder; 14. Heating box; 15. Fan; 16. Heating rod; Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0019] A stretching device for TPU film, such as Figure 1 -to Figure 4 As shown, it includes a stretching box 1 and a stretching mechanism embedded at both ends of the stretching box 1. The stretching mechanism includes two symmetrically arranged stretching cylinders 13, and a differential assembly is provided between the two stretching mechanisms. Both ends of the multiple stretching cylinders 13 are fixed with drive shafts 10 that are rotatably inserted into the stretching box 1. A heating box 14 is welded and fixed to one end of the stretching box 1, and a heat-insulating flow channel 8 is welded and fixed to the other end of the stretching box 1.

[0020] Both ends of the stretching box 1 are provided with feeding grooves 3, and both ends of the stretching box 1 are rotatably mounted with guide rollers 4. A TPU film body 9 is arranged between the two feeding grooves 3. A gear 12 is fixedly sleeved on one end of the drive shaft 10 passing through the stretching box 1. The two gears 12 on the same side are meshed with each other. The differential assembly includes a differential wheel 5 fixedly sleeved on the two drive shafts 10 and a differential belt 7 meshing between the two differential wheels 5. The size ratio of the two differential wheels 5 is 2:1, and the stretching ratio is 2:1 to 5:1, preferably 2:1. Part of the hot airflow generated in the heating box 14 heats and anneals the stretched TPU film body 9 along the heat preservation guide channel 8, reducing the stress generated after the TPU film body 9 is stretched. At the same time, another part of the hot airflow remains in the stretching box 1 to preheat the input TPU film body 9, improving the stretching effect of the TPU film body 9.

[0021] A motor 6 is fixedly installed on the outer wall of the stretching box 1. The motor shaft of the motor 6 is fixedly connected to the drive shaft 10. A transparent window 2 is embedded and fixedly attached to the top of the stretching box 1, which facilitates observation of the TPU film body 9 in the stretching box 1. Multiple heat-insulating and guiding channels 8 are U-shaped and welded to the outer wall of the stretching box 1. Heating rods and fans 15 are embedded and fixedly installed at both ends of the heating box 14. A dustproof net 11 is embedded and fixed to the outer wall of the heating box 14. The heat convection generated by the fan and electric heating rod 16 in the heating box 14 heats the TPU film body 9 between the two stretching mechanisms. The electric heating rod 16 is of model HTS and the heating temperature is 90-160 degrees Celsius, which avoids damage to the TPU film body 9 due to excessive temperature. The hot air flows from both sides of the TPU film body 9, which avoids uneven temperature on both sides of the TPU film body 9 and reduces the misalignment of the TPU film body 9 during the stretching process.

[0022] The working principle of this utility model is as follows: During use, the TPU film body 9 enters the stretching box 1 from the feeding trough 3. The motor 6 is started to drive the drive shaft 10 and the stretching cylinder 13 to rotate. The fan 15 and the electric heating rod 16 are started, so that the heating box 14 inputs high-temperature air into the stretching box 1 to heat the TPU film body 9. The two stretching cylinders 13 on the same side rotate synchronously through the gear 12 to transport the tightly connected TPU film body 9. At the same time, the two sets of stretching cylinders 13 rotate at different speeds through two differential wheels 5 of different sizes. The stretching cylinders 13 stretch the heated TPU film body 9. The stretching is achieved by using the speed difference of two or more sets of rollers. The hot airflow heats the stretched TPU along the heat preservation guide channel 8 and performs annealing treatment on the stretched TPU film to reduce internal stress and improve dimensional stability.

[0023] Although embodiments of the present invention have been shown and described, these specific embodiments are merely explanations of the present invention and are not intended to limit the invention. The specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions, and variations to the embodiments as needed without departing from the principles and spirit of the present invention, provided that such modifications, substitutions, and variations are within the scope of the claims of the present invention and are protected by patent law.

Claims

1. A stretching device for TPU film, comprising a stretching box (1) and stretching mechanisms embedded at both ends of the stretching box (1), characterized in that: The stretching mechanism includes two symmetrically arranged stretching cylinders (13), and a differential assembly is provided between the two stretching mechanisms. Both ends of the stretching cylinders (13) are fixed with drive shafts (10) that are rotatably inserted into the stretching box (1). A heating box (14) is welded to one end of the stretching box (1), and a heat-insulating flow channel (8) is welded to the other end of the stretching box (1).

2. The stretching device for TPU film according to claim 1, characterized in that: The stretching box (1) has feeding slots (3) at both ends, and guide rollers (4) are rotatably installed at both ends of the stretching box (1). A TPU film body (9) is provided between the two feeding slots (3).

3. The stretching device for TPU film according to claim 1, characterized in that: The drive shaft (10) passes through one end of the tension box (1) and is fixedly fitted with a gear (12), and the two gears (12) on the same side are meshed with each other.

4. The stretching device for TPU film according to claim 3, characterized in that: The differential assembly includes differential wheels (5) fixedly sleeved on two drive shafts (10) and a differential belt (7) meshing between the two differential wheels (5), with the size ratio of the two differential wheels (5) being 2:

1.

5. A stretching device for TPU film according to claim 4, characterized in that: A motor (6) is fixedly installed on the outer wall of the stretching box (1), and the motor shaft (6) is fixedly connected to the drive shaft (10).

6. The stretching device for TPU film according to claim 1, characterized in that: The top of the stretching box (1) is embedded with a transparent window (2) and the multiple heat-insulating flow channels (8) are U-shaped and welded to the outer wall of the stretching box (1).

7. The stretching device for TPU film according to claim 1, characterized in that: Heating rods and fans (15) are respectively embedded and fixed at both ends of the heating box (14), and a dustproof net (11) is embedded and fixed on the outer wall of the heating box (14).

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