Fluororesin film and method for manufacturing fluororesin film

Abstract

The present invention provides a fluororesin film capable of ensuring heat-resistant adhesion to a rubber layer, and a method for manufacturing a fluororesin film that can standardize the processing quality of laser etching. [Solution] The fluororesin film of the present invention is characterized by having a treated surface, wherein the ratio to untreated surface, represented by Formula 1, is 1.22 or more. The method for manufacturing the fluororesin film of the present invention comprises the step of forming a treated surface by laser etching the surface of a fluororesin film, wherein the ratio to untreated surface, represented by Formula 1, is 1.22 or more. [Equation 1]: Surface area after laser etching (m²) 2 ) / Surface area before laser etching (m²) 2 )

Description

Technical Field

[0001] The present invention relates to a fluororesin film and a method for manufacturing the same, and particularly to a fluororesin film capable of ensuring good heat resistance adhesiveness with a rubber layer and a method for manufacturing a fluororesin film capable of leveling the processing quality of laser etching treatment.

Background Art

[0002] In image forming apparatuses such as copying machines and laser beam printers, rubber members having a multilayer structure in which a release layer is provided on the surface layer of a rubber elastic layer are used for fixing rollers, fixing belts, pressure rollers, charging rollers, developing rollers, transfer rollers, and the like. A rubber roller is manufactured by providing a rubber layer on the outer peripheral surface of a core material such as aluminum or iron and providing a release layer made of a fluororesin film on the surface of the rubber layer. A fixing belt is manufactured by providing a rubber layer on the outer peripheral surface of a core material such as polyimide or nickel and providing a release layer made of a fluororesin film on the surface of the rubber layer. Although fluororesin has high releasability and abrasion resistance and is suitable for a release layer, its surface is inert, so its adhesiveness with a rubber layer is poor. For this reason, the fluororesin film is surface-treated in order to enhance the adhesiveness of the fluororesin film with the rubber layer. As surface treatment methods for fluororesin films, there are chemical etching that generates fine irregularities on the film surface using chemicals such as acids and alkalis, and laser etching (Patent Documents 1 and 2) that directly processes the film surface using high-energy lasers to form irregularities. Since chemical etching generates waste acid solutions and waste alkali solutions, it has a large environmental load. In recent years when environmental considerations are emphasized, laser etching that can form a precise surface structure by selectively treating the processing range without using chemical agents is widely used.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0004] Laser etching is prone to uneven processing due to the influence of heat distribution and energy intensity. This can lead to variations in the quality of the bonding interface with the rubber layer, making it difficult to consistently ensure adhesion and durability. The present invention aims to overcome the above-mentioned problems of the prior art, standardize the processing quality of laser etching treatment for fluororesin films, and stably ensure high quality. [Means for solving the problem]

[0005] The fluororesin film of the present invention is a fluororesin film that constitutes a release layer which is the surface layer of a rubber elastic layer, and is characterized in that it has a treated surface, and the ratio to untreated surface, represented by Formula 1, is 1.22 or more on the treated surface. [Equation 1]: Surface area after laser etching (m²) 2 ) / Surface area before laser etching (m²) 2 )

[0006] The fluororesin film of the present invention may have a treated surface with a ratio of 1.28 or higher compared to the untreated surface.

[0007] The fluororesin film of the present invention may have a treated surface with a ratio of 1.6 or less compared to the untreated surface.

[0008] The present invention relates to a method for manufacturing a fluororesin film, which is a release layer that forms the surface layer of a rubber elastic layer. The method comprises the step of laser etching the surface of the fluororesin film to form a treated surface, characterized in that the ratio of the untreated surface to the treated surface, as represented by Formula 1, is 1.22 or higher. [Equation 1]: Surface area after laser etching (m²) 2) / Surface area before laser etching (m²) 2 )

[0009] In the method for producing the fluororesin film of the present invention, the ratio of the treated surface to the untreated surface may be 1.28 or higher.

[0010] In the method for producing the fluororesin film of the present invention, the ratio of the treated surface to the untreated surface may be 1.6 or less. [Effects of the Invention]

[0011] According to the fluororesin film and method for manufacturing the fluororesin film of the present invention, by numerically controlling the comparison of the surface area before and after laser etching treatment with that of an untreated film, a fluororesin film of good quality can be stably manufactured. [Modes for carrying out the invention]

[0012] The fluororesin film and the method for producing the fluororesin film of the present invention will be described in detail below.

[0013] <1> Fluororesin film The fluororesin film of the present invention is a film that constitutes a release layer as the surface layer of a rubber elastic layer. The fluororesin film is mainly made of fluororesin and has a surface treated by laser etching. Examples of fluororesins that can be used include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), or tetrafluoroethylene-hexafluoropropylene-vinyl ether copolymer (THV). However, the fluororesin is not limited to these, and can be appropriately selected from various known fluororesins depending on the purpose and application. The fluororesin contains a light-absorbing material capable of absorbing laser light. The light-absorbing material includes carbon group elements, carbon group element compounds, metal oxides, metal sulfides, and mixtures thereof. The content of the light-absorbing material is preferably between 0.34 wt% and 5.8 wt%. However, the type and content of the light-absorbing material are not limited to this; essentially, any material that absorbs light within the wavelength range of the laser used at a predetermined content is acceptable. In addition, fluororesins can be blended with conductive agents such as conductive carbon, or high thermal conductivity agents such as metal oxides, as needed.

[0014] <2> Rubber rollers and belts The fluororesin film of the present invention can be applied to the release layer of rubber rollers and belts in image forming apparatus such as photocopiers and laser beam printers. The release layer is a layer for improving release properties from toner. The release layer can be configured as a tube structure that covers the outer circumference of the rubber layer. Rubber rollers include fixing rollers, pressure rollers, charging rollers, developing rollers, transfer rollers, etc. Belts include fixing belts, transfer belts, etc. However, the applications of rubber rollers and belts are not limited to image forming apparatuses; they can also be used as conveying rollers for printed materials, packaging, semiconductor products, food products, etc. Rubber rollers can be manufactured by laser etching the inner surface of a tubular fluororesin film, applying a primer to the treated surface, placing the tube in a mold, placing a core material inside the tube, injecting silicone rubber, and vulcanizing it for a predetermined time.

[0015] <3> laser For laser etching, various types of lasers can be selected, including solid-state lasers (YAG lasers), gas lasers (excimer lasers, argon lasers, CO2 lasers), and liquid lasers (organic dye lasers). Furthermore, the laser light used can accommodate a wide range of wavelengths, including ultraviolet and visible lasers. However, the laser and the wavelength of the laser light are not limited to these, and any laser and / or laser light may be used as long as it can satisfy a predetermined untreated comparison described later.

[0016] <4>Untreated comparison The fluororesin film and the method for producing the fluororesin film of the present invention have one feature in that they utilize an "untreated comparison", which is an index obtained by comparing the surface areas before and after the laser etching treatment, for the quality control of the fluororesin film. That is, the present invention has found that there is a significant correlation between the untreated comparison related to the laser etching treatment and the heat-resistant adhesiveness and tensile properties of the fluororesin film, and is an invention that achieves the leveling of the processing quality of the fluororesin film by using this untreated comparison. The untreated comparison is calculated by the following formula 1. [Formula 1] Surface area (m 2 ) after laser etching treatment / Surface area (m 2 ) before laser etching treatment Here, the "surface area before laser etching treatment" means the surface area of the fluororesin film before the laser etching treatment within the target range of the laser etching treatment, and the "surface area after laser etching treatment" means the surface area of the fluororesin film after the laser etching treatment within the target range of the laser etching treatment.

Example

[0017] <1>Surface treatment A PFA film was subjected to a laser etching treatment to form a treated surface, and the surface areas before and after the laser etching treatment were measured. · Laser: YAG laser · Wavelength: Third harmonic (355 nm) · Repetition frequency: 3,000 kHz · Output: 0.067 μJ to 0.173 μJ · Processing program: Vertical and horizontal · Pitch: 10 μm to 12 μm • Surface area measurement: Measured using a hybrid laser microscope (Lasertec Corporation: optelics® hybrid) with a 20x magnification / NA 0.8 lens.

[0018] <2> Heating test Silicone rubber was bonded to a test piece of fluororesin film, and an adhesion test was performed after heating.

[0019] <2.1> Preparation of test specimens Test specimens were prepared from PFA film tubes. (1) A PFA film tube is placed inside a cylindrical mold. (2) Laser processing (3) Apply a primer (Dow Toray Industries, Ltd.: SILASTIC® DY 39-067) to the treated surface of the PFA film tube and air dry. (4) Arrange the upper and lower molds and the core metal. (5) Inject silicone rubber (Shin-Etsu Chemical Co., Ltd.: SG-91H) into the PFA film tube. (6) Vulcanize at 120°C for 30 minutes (7) Secondary vulcanization: 200°C for 4 hours Test specimen • Thickness: 2mm Width x Length: 10mm x 30mm

[0020] <2.2> Heating of the test specimen The test specimen was heated for a predetermined time. ·Heating temperature: 230℃ • Heating time Test specimen A: 504 hours Test specimen B: 1008 hours

[0021] <2.3> Peel Test A 90-degree peel test was performed on the heated specimens, and the peeled surface was observed. (1) Fix the silicone rubber surface of the test specimen to the test plate. (2) The edge of the PFA film surface is pulled and fixed to the jig, and pulled upward at 10 mm / s, peeling it off at a 90° angle to the test plate. (3) Visual inspection and evaluation of the peeled surface [Evaluation Criteria] ○: Cohesive failure... Destruction of the silicone rubber interior ×: Interfacial fracture... Fracture at the bonding interface between silicone rubber and PFA film.

[0022] <2.4> Test results of the heating test The results of the heating test are shown in Table 1. There were 24 test specimens, numbered 1 through 24.

[0023] [Table 1]

[0024] <2.5> Analysis of the results of the heating test At 504 hours after heating, specimens 1, 9, and 17 all showed a value of 1.20 or less compared to the untreated specimen, indicating interfacial fracture at the bonding interface between the silicone rubber and the PFA film. On the other hand, specimens 2-8, 10-16, and 18-24 all showed a value of 1.22 or higher compared to the untreated specimen, indicating cohesive fracture within the silicone rubber. This is thought to be because the laser etching treatment increased the surface area and depth, resulting in a greater anchoring effect of the silicone rubber on the PFA film. At 1008 hours after heating, test specimens 1, 9, 10, 17, and 18 all showed a value of 1.24 or less compared to the untreated specimen, indicating interfacial fracture at the bonding interface between the silicone rubber and the PFA film. On the other hand, test specimens 2-8, 11-16, and 19-24 all showed a value of 1.28 or higher compared to the untreated specimen, indicating cohesive fracture within the silicone rubber. From the above, it was confirmed that there is a correlation between the untreated ratio after laser etching and the heat-resistant adhesion, and that the higher the untreated ratio, the higher the heat-resistant adhesion to silicone rubber. Furthermore, it was found that the untreated ratio after laser etching should preferably be 1.22 or higher, and even more preferably 1.28 or higher.

[0025] <3> Tensile test Tensile tests were performed on test specimens of fluororesin film. • Dumbbell-shaped tensile test specimen, type 6, compliant with JIS K 6251.

[0026] <3.1> Test results of the tensile test The results of the tensile test are shown in Table 2. There were eight test specimens, numbered 9 through 16. For use as a release layer on rubber rollers, it is desirable that the fluororesin film has a tensile strength of 15 MPa or higher and an elongation of 100% or higher.

[0027] [Table 2]

[0028] <3.2> Analysis of Tensile Test Results Test specimens 9-13 all had a ratio of 1.6 or less compared to the untreated specimen, with a tensile strength of 15 MPa or more and a tensile elongation of 100% or more. On the other hand, test specimens 14-16 all had a ratio greater than 1.6 compared to the untreated specimen, with a tensile strength of less than 15 MPa and a tensile elongation of less than 100%. This is thought to be because the laser irradiation in the thickness direction became deeper, resulting in larger physical damage to the test specimen and a decrease in mechanical strength. From the above, it was confirmed that there is a correlation between the untreated material and the tensile properties (tensile strength and tensile elongation) after laser etching, that the smaller the untreated material, the better the tensile properties, and that it is desirable for the untreated material to have a laser etching ratio of 1.6 or less.

Claims

1. A fluororesin film that constitutes the release layer, which is the surface layer of the rubber elastic layer, Equipped with a treated surface, The treated surface is characterized in that the untreated ratio represented by formula 1 is 1.22 or more. Fluoropolymer film. [Equation 1]: Surface area (m²) after laser etching. ２ ) / Surface area before laser etching (m²) ２ )

2. The treated surface is characterized in that the ratio to the untreated surface is 1.28 or higher. The fluororesin film according to claim 1.

3. The treated surface is characterized in that the ratio to the untreated surface is 1.6 or less. The fluororesin film according to claim 1 or 2.

4. A method for manufacturing a fluororesin film that constitutes the release layer, which is the surface layer of the rubber elastic layer, The process includes the step of forming a treated surface by laser etching the surface of a fluororesin film, The treated surface is characterized in that the untreated ratio represented by formula 1 is 1.22 or more. A method for manufacturing fluororesin film. [Equation 1]: Surface area (m²) after laser etching. ２ ) / Surface area before laser etching (m²) ２ )

5. The treated surface is characterized in that the ratio to the untreated surface is 1.28 or higher. A method for producing a fluororesin film according to claim 4.

6. The treated surface is characterized in that the ratio to the untreated surface is 1.6 or less. A method for producing a fluororesin film according to claim 4 or 5.

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