Stretching roll for preparing biaxially stretched film

Abstract

A kind of stretching roller for preparing bidirectional stretch film, including roller body, it is characterized in that: the roller body is hollow cylinder structure with certain camber on outer surface, two-stage spiral protrusions for increasing friction are formed on the outer surface of roller body, the center position of left and right ends of roller body is respectively equipped with detachable rotating shaft, wherein left rotating shaft is solid shaft, right rotating shaft is hollow rotating shaft, electric heating wire and temperature sensor are arranged in roller body.The present application has simple and reasonable structure, is convenient to disassemble and assemble, can realize pre-stretching, also can correct the movement direction of blank, prevent blank deviation, effectively improve product quality.

Description

Technical Field

[0001] This invention belongs to the field of biaxially oriented film preparation technology, and relates to a stretching roller for preparing biaxially oriented films. Background Technology

[0002] Biaxially Oriented Plastics Film (BOPF) is a product made through special physical, chemical, and mechanical processing. It involves stretching a thick film or flat sheet longitudinally and laterally at a temperature below its melting point and above its glass transition temperature, followed by heat setting under tension. BOPF offers advantages such as lightweight, moisture resistance, low air permeability, and high mechanical strength. It is widely used in packaging for food, pharmaceuticals, and daily light industrial products, and is also a major substrate for composite films.

[0003] Stretching temperature and stretch ratio are key factors affecting the transverse thickness uniformity of biaxially oriented plastic films. Transverse stretching is a crucial and complex process in biaxially oriented film production, conducted entirely within a continuous thermal environment. Studies have shown that the transverse stretching process has multiple stretching initiation points, primarily caused by weak points in the transverse thickness, high stretching rates, and factors such as impurities, bubbles, and surface defects in the film. Multiple stretching initiation points are prevalent in plastic film stretching, constituting unstable stretching and easily leading to uneven product thickness, thus affecting product quality.

[0004] Therefore, it is necessary to provide a multifunctional stretching roller that can be used before the transverse stretching process to achieve pre-transverse stretching and correct the movement direction of the billet to prevent the billet from deviating. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a stretching roller for preparing biaxially oriented films with a simple and reasonable structure and good performance, which can achieve pre-stretching and correct the movement direction of the blank to prevent the blank from deviating.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a stretching roller for preparing biaxially oriented films, comprising a roller body, characterized in that: the roller body is a hollow cylindrical structure with a certain curvature on the outer surface, the outer surface of the roller body is formed with two-stage spiral protrusions for increasing friction, and detachable rotating shafts are respectively installed at the center positions of the left and right ends of the roller body, wherein the left rotating shaft is a solid shaft and the right rotating shaft is a hollow shaft, and an electric heating wire and a temperature sensor are provided inside the roller body.

[0007] As an improvement, the outer surface of the roller body has a circular arc structure with a high center and low sides, and the roller surface is a smooth polished surface. The first-level spiral protrusions of the two-stage spiral protrusions are symmetrically distributed with respect to the middle longitudinal section of the roller body, with opposite rotation directions, and the protrusions are circular arc-shaped with a large radius. The second-level spiral protrusions are distributed on the surface of the first-level protrusions, with the same rotation direction as the first-level spiral protrusions, and the protrusions are circular arc-shaped with a smaller radius.

[0008] Furthermore, the left end of the roller body is closed and the right end is open. The left end of the solid shaft on the left side is recessed with a keyway, and the right end is provided with a flange. The solid shaft is fixedly connected to the roller body by bolts through the flange.

[0009] Furthermore, a right cover plate is fitted at the right end opening of the roller body, and the left end of the hollow rotating shaft on the right side is fixedly set at the center of the outer end face of the right cover plate. A fixed shaft passes through the hollow rotating shaft, and a ball bearing is provided between the hollow rotating shaft and the fixed shaft to facilitate the rotation of the hollow rotating shaft.

[0010] Furthermore, the right cover plate has several fixing holes on its edge, and the right cover plate is fixed to the right opening of the roller body by bolts. The fixing shaft is a hollow shaft, and the right end of the fixing shaft is fixed to the frame.

[0011] Furthermore, the roller body is provided with a bracket for power supply heating wire. The bracket is horizontally positioned in the middle of the roller body, and the right end of the bracket is fixedly connected to the inner side of the right cover plate.

[0012] Finally, the temperature sensor is located in the middle of the inner wall of the roller, and a central through hole is opened in the center of the right cover plate, which is connected to the hollow rotating shaft and the fixed shaft. The wires of the electric heating wire and the signal line of the temperature sensor pass through the central through hole and are led out from the center of the fixed shaft.

[0013] Compared with the prior art, the advantages of the present invention are as follows:

[0014] 1. The roller body has a controllable temperature heat source inside, which can be used in the open environment during the film preform transfer process, saving energy;

[0015] 2. The roller forming has two levels of spiral protrusions, which can increase the friction between the roller surface and the film. The first level of spiral protrusions is symmetrically distributed in the longitudinal section of the middle of the roller and rotates in opposite directions during operation. During the operation, it can provide a pulling force to both ends of the roller to the blank, realizing the pre-stretching of the film blank.

[0016] Third, the roller surface is designed with a circular arc shape that is high in the center and low on both sides. When the film preform deviates, the preform at both ends of the roller's longitudinal section is stretched unevenly. In the direction of deviation, the edge of the preform is closer to the end of the roller (diameter decreases), and the amount of preform stretching decreases. In the opposite direction of deviation, the edge of the preform is closer to the center of the roller's longitudinal section (diameter increases), and the amount of stretching increases. The tension of the preform increases, causing the preform to move closer to the center of the roller, thereby correcting the direction of preform movement, preventing preform deviance, uneven stretching, and affecting film quality.

[0017] The present invention has a simple and reasonable structure, is easy to assemble and disassemble, can achieve pre-stretching, and can also correct the movement direction of the billet, prevent the billet from deviating, and effectively improve product quality. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0020] like Figure 1 As shown, a stretching roller for preparing biaxially oriented films includes a roller body 1, which is a hollow cylindrical structure with a certain curvature on its outer surface. The outer surface of the roller body 1 is formed with two-stage spiral protrusions 2 and 3 to increase friction. Removable rotating shafts are installed at the center positions of the left and right ends of the roller body 1, wherein the left rotating shaft is a solid shaft 8 and the right rotating shaft is a hollow rotating shaft 6. An electric heating wire 10 and a temperature sensor 4 are provided inside the roller body 1.

[0021] The specific structure is as follows: The outer surface of the roller body 1 has a circular arc structure with a high center and low sides. The roller surface is a smooth polished surface. The first-stage spiral protrusion 2 of the two-stage spiral protrusions 2 and 3 is symmetrically distributed around the middle longitudinal section of the roller body 1, with opposite rotation directions. The protrusion is arc-shaped and has a large radius. The second-stage spiral protrusion 3 is distributed on the surface of the first-stage protrusion, with the same rotation direction as the first-stage spiral protrusion 2. The protrusion is arc-shaped and has a smaller radius. The function of setting the two-stage spiral protrusions 2 and 3 is to increase the friction between the roller surface and the film, and at the same time, to provide a pulling force to both ends of the roller to the preform, thereby achieving pre-stretching of the film preform.

[0022] The roller body 1 is closed at the left end and open at the right end. A solid shaft 8 on the left side has a keyway 16 recessed at its left end and a flange 17 at its right end. The solid shaft 8 is fixedly connected to the roller body 1 via the flange 17 and bolts 11. A right cover plate 5 aligns with the opening at the right end of the roller body 1. The left end of a hollow rotating shaft 6 on the right side is fixedly positioned at the center of the outer end face of the right cover plate 5. A fixed shaft 7 passes through the hollow rotating shaft 6, and a ball bearing 13 is provided between the hollow rotating shaft 6 and the fixed shaft 7 to facilitate the rotation of the hollow rotating shaft 6. Several fixing holes are provided on the edge of the right cover plate 5. The right cover plate 5 is fixed to the right opening of the roller body 1 via bolts 12. The fixed shaft 7 is a hollow shaft, and its right end is fixed to the frame; the fixed shaft 7 does not rotate.

[0023] The roller body 1 is equipped with a bracket 9 for the heating wire 10. The bracket 9 is horizontally positioned in the middle of the roller body 1, and its right end is fixedly connected to the inner side of the right cover plate 5. The temperature sensor 4 is located in the middle of the inner wall of the roller body 1. The center of the right cover plate 5 has a central through hole that communicates with the hollow rotating shaft 6 and the fixed shaft 7. The wire 14 of the heating wire 10 and the signal line 15 of the temperature sensor 4 pass through the central through hole and are led out from the center of the fixed shaft 7.

[0024] In use, first fix the ball bearing 13 to the fixed shaft 7, fix the temperature sensor 4 to the inside of the roller body 1, fix the electric heating wire 10 to the bracket 9, fix the bracket 9 to the inside of the right cover plate 5, and pass the wire 14 of the electric heating wire 10 and the signal wire 15 of the temperature sensor 4 out from the center of the hollow rotating shaft 6; then use bolts 12 to fix the right cover plate 5 to the right end face of the roller body 1, install the fixed shaft 7 in the working position, and then install the hollow rotating shaft 6 on the right side of the assembled roller body 1 on the fixed shaft 7, and pass the wire 14 and the signal wire 15 out from the center of the fixed shaft 7; finally, connect and fix the flange 17 to the roller body 1 with bolts 11, and put the solid shaft 8 into the working position.

[0025] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A stretching roller for preparing biaxially oriented films, comprising a roller body, characterized in that: The roller body is a hollow cylindrical structure with a certain curvature on its outer surface and a high center and low sides. The outer surface of the roller body is formed with two-stage spiral protrusions to increase friction. Removable rotating shafts are installed at the center of the left and right ends of the roller body, with the left rotating shaft being a solid shaft and the right rotating shaft being a hollow shaft. The roller body is equipped with an electric heating wire and a temperature sensor for temperature control. The first-stage spiral protrusions of the two-stage spiral protrusions are symmetrically distributed on the longitudinal section of the middle of the roller body, with opposite rotation directions. The protrusions are arc-shaped and have a large radius. Multiple second-stage spiral protrusions are distributed on the surface of each first-stage protrusion, with the same rotation direction as the first-stage spiral protrusion. The protrusions are arc-shaped and have a smaller radius.

2. The stretching roller for preparing biaxially oriented films according to claim 1, characterized in that: The roller surface of the roller body is a smooth, polished surface.

3. The stretching roller for preparing biaxially oriented films according to claim 2, characterized in that: The roller body is closed at the left end and open at the right end. The solid shaft on the left side has a keyway recessed at the left end and a flange at the right end. The solid shaft is fixedly connected to the roller body by bolts through the flange.

4. The stretching roller for preparing biaxially oriented films according to claim 3, characterized in that: The right end opening of the roller body is fitted with a right cover plate, and the left end of the hollow rotating shaft on the right side is fixedly set at the center of the outer end face of the right cover plate. A fixed shaft passes through the hollow rotating shaft, and a ball bearing is provided between the hollow rotating shaft and the fixed shaft to facilitate the rotation of the hollow rotating shaft.

5. The stretching roller for preparing biaxially oriented films according to claim 4, characterized in that: The right cover plate has several fixing holes on its edge. The right cover plate is fixed to the right opening of the roller body by bolts. The fixing shaft is a hollow shaft, and the right end of the fixing shaft is fixed to the frame.

6. The stretching roller for preparing biaxially oriented films according to claim 5, characterized in that: The roller body is equipped with a bracket for power supply heating wire. The bracket is horizontally positioned in the middle of the roller body, and the right end of the bracket is fixedly connected to the inner side of the right cover plate.

7. The stretching roller for preparing biaxially oriented films according to claim 6, characterized in that: The temperature sensor is located in the middle of the inner wall of the roller. A central through hole is opened in the center of the right cover plate, which is connected to the hollow rotating shaft and the fixed shaft. The wires of the electric heating wire and the signal line of the temperature sensor pass through the central through hole and are led out from the center of the fixed shaft.

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