Film stretching roller

Abstract

A film stretching roller comprises a roller core, the outer side of the roller core is coated with a roller skin, the outer side of the roller skin is coated with a liquid silicone rubber layer, chopped fibers are evenly distributed in the liquid silicone rubber layer, and the chopped fibers are glass fibers, carbon fibers or Kevlar fibers. The outer side of the liquid silicone rubber layer is coated with a liquid silicone layer, and the outer side of the liquid silicone layer is provided with a surface coating. A film stretching roller of the utility model is provided with chopped fibers in the liquid silicone rubber layer, and these chopped fibers are evenly dispersed in the liquid silicone rubber layer, which significantly improves the tear resistance of the liquid silicone while maintaining other excellent properties of the liquid silicone. A layer of pure liquid silicone is coated on the surface of the liquid silicone rubber layer to form a uniform and smooth protective layer. The thickness of this layer of pure liquid silicone is usually controlled at 2-3 mm, which can protect the film from the influence of the fibers and maintain the shape and performance of the roller surface.

Description

Technical Field

[0001] The utility model relates to the field of machinery, in particular to a roller structure, in particular to a film stretching roller. Background Art

[0002] In the field of biaxially oriented film production technology, in order to improve the physical and mechanical properties of the film, such as transparency, tensile strength, toughness, gloss, etc., it is usually necessary to biaxially stretch the film, that is, stretch it in the machine direction (MD) and transverse direction (TD). The MDO (Machine Direction Orientation) roller is a key device for stretching the film in the machine direction.

[0003] The background of the use of MDO rollers is that by stretching the film in the machine direction, the film can be oriented in the machine direction to improve its physical and mechanical properties.

[0004] In the production of biaxially oriented films (BOPP, BOPET, etc.), especially in the manufacture of optical-grade films, liquid silicone rollers (also called liquid silicone rollers) are used to achieve optical performance requirements such as high transparency and low haze. The application of liquid silicone rollers in the production of optical films is mainly due to the following reasons:

[0005] Excellent surface finish: Liquid silicone rollers have a very high surface finish, which can reduce film surface defects and improve film transparency and gloss. This is critical for optical films, which need to have good light transmittance and reflection properties.

[0006] Excellent temperature resistance: Liquid silicone rollers can withstand high temperature environments without deformation or damage, which makes them suitable for use in high temperature stretching processes, ensuring stable performance of the rollers during production.

[0007] Anti-stickiness: Liquid silicone roller has excellent anti-stickiness, which can effectively reduce the adhesion of the film to the roller during the production process and avoid surface defects of the film caused by adhesion.

[0008] Wear resistance: Liquid silicone roller has good wear resistance and can maintain its surface smoothness and shape during long-term use, reducing the frequency of replacement and maintenance.

[0009] Adjustable hardness: The hardness of the liquid silicone roller can be adjusted according to the needs of the production process to adapt to different stretching requirements and film characteristics.

[0010] Chemical corrosion resistance: Liquid silicone roller has good chemical corrosion resistance, can resist the erosion of various chemicals, and extend the service life of the roller.

[0011] In the production of biaxially oriented films, especially for the manufacture of optical-grade films, the rubber layer of the MDO roller is crucial to ensure the quality of the film. Liquid silicone rollers are selected for their excellent surface finish and temperature resistance, but since the liquid silicone body has poor tear resistance, the existing liquid silicone MDO rollers usually adopt a double-layer structure design, with solid silicone or EPDM rubber as the bottom layer, using the good tear resistance of these materials as the basis of the roller body, with a thickness of about 5-8mm. The surface layer uses liquid silicone rubber with a thickness of about 5-7mm to give full play to its advantages, such as high transparency and gloss.

[0012] However, since this double-layer structure requires two different materials to be combined into a whole, the roller core of the roller body must first be pre-treated, and then the base rubber must be coated, vulcanized, glued, ground and aged to complete the base rubber treatment. Then, the base rubber surface must be treated, and liquid silicone coating, vulcanization, aging, glued and ground must be performed, which results in a relatively complex manufacturing process and low production efficiency. Summary of the invention

[0013] The utility model aims to provide a film stretching roller, which can solve the technical problems of relatively complex manufacturing process and low production efficiency of double-layer liquid silicone roller in the prior art.

[0014] The utility model discloses a film stretching roller, comprising a roller core, the outer side of the roller core is covered with a roller skin, the outer side of the roller skin is covered with a liquid silicone rubber layer, short-cut fibers are evenly distributed in the liquid silicone rubber layer, and the short-cut fibers are glass fibers, carbon fibers or Kevlar fibers. The outer side of the liquid silicone rubber layer is covered with a liquid silicone layer, and the outer side of the liquid silicone layer is provided with a surface coating.

[0015] Furthermore, the thickness of the liquid silicone layer is 2-3 mm.

[0016] Furthermore, the surface coating is a low surface energy coating.

[0017] Compared with the prior art, the utility model has a positive and obvious effect. A film stretching roller of the utility model is provided with chopped fibers in the liquid silicone rubber layer, and these chopped fibers are evenly dispersed in the liquid silicone rubber layer, which significantly improves the tear resistance of the liquid silicone while maintaining other excellent properties of the liquid silicone. A layer of pure liquid silicone is coated on the surface of the liquid silicone rubber layer to form a uniform and smooth protective layer. The thickness of this layer of pure liquid silicone is usually controlled at 2-3mm, which can protect the film from the influence of the fibers and maintain the shape and performance of the roller surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1It is a schematic diagram of a film stretching roller of the utility model.

[0019] Figure 2 for Figure 1 A partial enlarged schematic diagram of . DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with an embodiment, but the present invention is not limited to the embodiment. Any similar structure and similar changes of the present invention should be included in the protection scope of the present invention. The use of directions such as up, down, front, back, left, and right in the present invention is only for the convenience of clear description and is not a limitation on the technical solution of the present invention.

[0021] like Figure 1 and Figure 2 As shown, a film stretching roller of the utility model comprises a roller core 1, the outer side of the roller core 1 is coated with a roller skin 2, the outer side of the roller skin 2 is coated with a liquid silicone rubber layer 3, short-cut fibers are evenly distributed in the liquid silicone rubber layer 3, and the short-cut fibers are glass fibers, carbon fibers or Kevlar fibers. The outer side of the liquid silicone rubber layer 3 is coated with a liquid silicone layer 4, and the outer side of the liquid silicone layer 4 is provided with a surface coating.

[0022] Furthermore, the thickness of the liquid silicone layer 4 is 2-3 mm.

[0023] Furthermore, the surface coating is a low surface energy coating.

[0024] Specifically, the roller core 1, roller skin 2, liquid silicone rubber layer 3, chopped fibers, liquid silicone layer 4, low surface energy coating, etc. in this embodiment all adopt well-known solutions in the prior art, which are well understood by those skilled in the art and will not be described in detail here.

[0025] The working principle of this embodiment:

[0026] Roller core 1: It supports the entire roller body and is generally made of carbon steel.

[0027] Roller skin 2: Generally made of carbon steel, aluminum or composite materials.

[0028] Liquid silicone rubber layer 3 with chopped fibers: It can be made into a functional surface coating as needed, such as a low surface energy coating to increase the friction resistance, corrosion resistance and other related functions of the roller.

[0029] In view of the complexity of the existing liquid silicone MDO roller manufacturing process, the utility model proposes an innovative single-layer structure design, which aims to simplify the manufacturing process and merge the traditional two-layer encapsulation process into one-layer encapsulation, thereby greatly shortening the production cycle and reducing processing costs.

[0030] Single-layer structure design: The utility model adopts a single rubber layer to replace the traditional double-layer structure. The single layer has the required tear resistance and maintains the advantages of the surface layer liquid silicone rubber, such as high transparency and glossiness.

[0031] Chopped fiber reinforcement: In order to compensate for the insufficient tear resistance of the liquid silicone itself, the utility model arranges chopped fibers in the liquid silicone rubber layer 3. These chopped fibers are evenly dispersed in the liquid silicone rubber layer 3, which significantly improves the tear resistance of the liquid silicone while maintaining other excellent properties of the liquid silicone.

[0032] Through the above scheme, the utility model not only simplifies the manufacturing process of the MDO roller, but also improves the comprehensive performance of the roller body, making it more suitable for the production of biaxially oriented films, especially optical-grade films. This single-layer MDO roller is expected to greatly improve production efficiency and reduce costs while ensuring the quality and performance of film products.

[0033] The single-layer structure of the utility model adopts a casting process.

[0034] Fiber selection:

[0035] Glass Fiber: Glass fibers have excellent mechanical strength and good heat resistance. They can withstand high temperatures and will not melt or degrade during the rubber vulcanization process.

[0036] Carbon Fiber: Carbon fibers have extremely high strength and modulus, as well as good heat and chemical resistance. They provide excellent reinforcement, but may have some impact on the transparency of the silicone.

[0037] Kevlar: Kevlar fibers are known for their exceptional strength and tear resistance, while also having good heat resistance and chemical stability. They are often used in applications that require high tear resistance.

[0038] The surface quality of the MDO roller is crucial to the quality of the final film. In order to prevent the short fibers in the liquid silicone rubber layer 3 from potentially scratching or damaging the film surface, a layer of pure liquid silicone rubber layer 4 is coated on the surface of the liquid silicone rubber layer 3 to form a uniform and smooth protective layer. The thickness of this layer of pure liquid silicone is usually controlled at 2-3mm, which can protect the film from the influence of the fibers and maintain the shape and performance of the roller surface.

[0039] In the process of applying pure liquid silicone, the following methods can be used:

[0040] Direct casting: This method involves casting liquid silicone directly onto the surface of the liquid silicone rubber layer 3 that has been vulcanized and embedded with chopped fibers. During the casting process, it is necessary to ensure that the silicone is evenly distributed and there are no bubbles or defects. This method is suitable for cases where the roller surface shape is relatively simple.

[0041] Scraping: Scraping is a more precise coating method, especially suitable for roller surfaces with complex shapes. Using a scraper or similar tool to evenly apply the silicone to the roller surface can better control the thickness and uniformity of the coating. This method also needs to be carried out in a professional operating environment to ensure the quality of the coating.

[0042] After the MDO rollers with pure liquid silicone layer 4 are put into use, they can significantly improve the production efficiency and product quality of the film. The silicone layer can not only protect the film from damage by the chopped fibers, but also reduce the friction between the film and the roller surface, reduce energy consumption, and increase the running speed of the production line. At the same time, the smooth roller surface also helps to improve the transparency and gloss of the film, meeting the high standards of optical-grade films.

Claims

1. A film stretching roller, characterized in that: The invention comprises a roller core (1), wherein the outer side of the roller core (1) is coated with a roller skin (2), the outer side of the roller skin (2) is coated with a liquid silicone rubber layer (3), short-cut fibers are evenly distributed in the liquid silicone rubber layer (3), and the short-cut fibers are glass fibers, carbon fibers or Kevlar fibers. The outer side of the liquid silicone rubber layer (3) is coated with a liquid silicone layer (4), and the outer side of the liquid silicone layer (4) is provided with a surface coating.

2. A film stretching roller according to claim 1, characterized in that: The thickness of the liquid silicone layer (4) is 2-3 mm.

3. The film stretching roller according to claim 1, characterized in that: The surface coating is a low surface energy coating.

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