A rubberized fabric sheet forming process

Abstract

The application provides a rubber cloth sandwiched membrane forming process and belongs to the technical field of molds. The application comprises the following steps: placing a middle mold plate between an upper mold plate and a lower mold plate, and then first closing the mold; injecting rubber raw materials into an upper mold cavity, a lower mold cavity and an auxiliary material groove, and then first vulcanizing after the injection is completed; opening the mold after the rubber is vulcanized, then taking out the middle mold plate, laying cloth on the rubber surface attached to the lower mold plate, second closing the mold for second vulcanization, and then taking out the product with the auxiliary material handle after the vulcanization is completed; and cutting off the auxiliary material handle to obtain the rubber cloth sandwiched membrane. The process can ensure uniform rubber flow distribution, realize close and flat combination of the rubber and the cloth, and significantly improve product quality and use performance.

Description

Technical Field

[0001] This invention relates to a process for forming rubber-insulated fabric films, belonging to the field of mold technology. Background Technology

[0002] Rubber-lined fabric diaphragms, due to their excellent mechanical and sealing properties, are widely used in hydraulic, pneumatic, and many other fields. The molds for manufacturing rubber-lined fabric diaphragms typically consist of two parts: an upper mold and a lower mold. These molds interlock via a convex-concave structure to form the required shape and size when the rubber-lined fabric diaphragm is pressed within the mold. In general rubber-lined fabric diaphragm production, a suitable mold is selected based on the product design requirements. Currently, the molding process commonly used by existing rubber-lined fabric diaphragm manufacturers involves simultaneously placing a rubber sheet and fabric in a mold for one-time vulcanization molding, such as... Figure 1 As shown. However, this traditional molding method has many insurmountable technical defects, which seriously affect the quality and functionality of the product.

[0003] Specifically, the main problems with traditional processes include the following: First, during the vulcanization process, the flow characteristics of the rubber after heating are hindered by the fabric, easily leading to uneven rubber flow distribution, resulting in differences in thickness and density in different areas of the diaphragm. Second, the rubber cannot form a stable wrapping and positioning of the fabric during the flow process, easily causing the fabric to leak onto the rubber surface, which not only affects the appearance quality of the product but also reduces the sealing performance and service life of the diaphragm. Third, the fabric inside the product is easily pulled and squeezed by the flow of rubber during vulcanization, resulting in wrinkles. This defect significantly reduces the strength and fatigue resistance of the diaphragm, directly affecting the product's functionality.

[0004] In the prior art, Chinese utility model patent application number 201620077013.3 discloses a fabric-reinforced membrane mold for preventing wrinkles and tears, comprising a lower template, a middle template, an upper template, a lower mold core, an upper mold core, and an elastic adjusting ring. The lower template, middle template, and upper template are detachably connected from bottom to top. The lower mold core is mounted on the lower template, and the side of the lower mold core away from the lower template has a frustum structure. The elastic adjusting ring is mounted on the annular groove of the lower mold core. The middle template has multiple conical holes, and the middle template can be connected to multiple lower mold cores. The middle template can be fitted onto the frustum structure of the lower mold core, and the conical holes on the middle template correspond one-to-one with the lower mold cores. The upper mold core is mounted on the upper template, and the end of the upper mold core away from the upper template has a protrusion that matches the shape of the mold groove. The protrusion on the upper mold core can be pressed down into the mold stop of the lower mold core. The first end of the elastic element is installed on the side of the upper template close to the middle template. This utility model can prevent the fabric membrane from being wrinkled or torn during the production process through its elasticity.

[0005] However, this device still uses a one-time molding process, and the elasticity of the elastic element is insufficient to fully withstand the force when the mold closes, thus affecting the molding effect.

[0006] The Chinese invention patent authorization announcement number is CN103770439B, which discloses a method for producing an ultra-thin fluorosilicone rubber-lined membrane. The method involves pre-pressing the rubber and then placing the fabric in for vulcanization. However, the steel plate only serves as an isolation element and does not have the function of cavity forming. Furthermore, it relies on a PTFE coating to prevent the rubber from sticking together.

[0007] Therefore, there is an urgent need for a suitable process for forming rubber-insulated diaphragms to solve the above problems. Summary of the Invention

[0008] The purpose of this invention is to overcome the defects in the existing rubber-cloth-insulated diaphragm forming process, such as uneven rubber flow, easy leakage of fabric, and easy wrinkling of fabric. This invention provides a rubber-cloth-insulated diaphragm forming process that can ensure uniform rubber flow distribution, achieve a tight and smooth bond between rubber and fabric, and significantly improve product quality and performance.

[0009] The technical solution adopted in this invention is a process for forming rubber-insulated fabric diaphragms, comprising the following steps:

[0010] S1, place the middle template between the upper template and the lower template, and then close the mold for the first time; the lower surface of the upper template and the upper surface of the lower template are provided with several auxiliary material grooves, and the upper mold cavity and the lower mold cavity are respectively connected to the auxiliary material grooves on the same side;

[0011] S2, the rubber raw material is injected into the upper mold cavity formed between the upper mold plate and the middle mold plate, the lower mold cavity formed between the middle mold plate and the lower mold plate, and the auxiliary material groove. After the injection is completed, the first vulcanization is carried out.

[0012] S3, after the rubber vulcanization is completed, the mold is opened. Then, the middle mold is taken out first, and the fabric is laid on the rubber surface attached to the lower mold. The mold is closed for the second time for the second vulcanization process. After the vulcanization is completed, the product with the auxiliary material is taken out.

[0013] S4, by cutting off the auxiliary material, a rubber-coated fabric film is obtained.

[0014] As a further aspect of the present invention, the vulcanization temperature is 160±5℃ and the vulcanization pressure is 8±0.5MPa.

[0015] As a further embodiment of the present invention, the shapes of the upper mold cavity and the lower mold cavity are the same as those of the pre-formed rubber-insulated film.

[0016] As a further embodiment of the present invention, the inner layer of the rubber-insulated membrane is made of fabric, and the upper and lower surfaces of the fabric are made of rubber.

[0017] As a further aspect of the present invention, the time for the first vulcanization is 100±10 seconds.

[0018] As a further aspect of the present invention, the second vulcanization time is 230±10 seconds.

[0019] As a further aspect of the present invention, the temperature and pressure of the first vulcanization and the second vulcanization are the same.

[0020] As a further embodiment of the present invention, the auxiliary material makes the groove opening flush with the template surface, and the bottom diameter of the groove is larger than the opening diameter.

[0021] This invention discloses a process for forming rubber-lined fabric diaphragms. Its advantages are as follows: Compared to existing technologies, this invention employs a method of first injecting rubber into the mold cavity and then performing a first vulcanization. Without fabric obstruction, this ensures uniform rubber distribution within the mold cavity, effectively avoiding the uneven rubber distribution problem caused by fabric obstruction in traditional processes. The rubber after the first vulcanization has formed a stable shape, allowing for precise positioning of the fabric on the rubber surface during subsequent fabric laying. Furthermore, the bonding between the rubber and fabric during the second vulcanization process occurs on the basis of the stable rubber shape, effectively preventing fabric leakage onto the rubber surface and improving the product's appearance quality and sealing performance. The fabric can be laid flat directly on the vulcanized rubber surface, and the second vulcanization ensures a tight bond between the fabric and rubber, fundamentally solving the problem of wrinkles easily forming in the fabric inside the product in traditional processes, significantly improving the strength and fatigue resistance of the diaphragm. Unlike existing technologies that rely on PTFE coatings to prevent adhesion, this invention sets flared auxiliary material grooves on the upper and lower templates, so that the rubber is integrally formed with the auxiliary material during vulcanization. By utilizing the mechanical interlocking adhesion between the auxiliary material and the groove, the rubber layer is stably attached to the upper and lower templates, thus avoiding the rubber layer from falling off or sticking to the middle template when the mold is opened without the need for special coatings. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of a cross-section of existing technology;

[0024] Figure 2 This is a schematic cross-sectional view of the rubber before the first vulcanization of the present invention;

[0025] Figure 3This is a schematic diagram of mold opening after the rubber vulcanization is completed according to the present invention;

[0026] Figure 4 This is a schematic diagram of the invention before the second vulcanization;

[0027] Figure 5 This is a schematic diagram of the second vulcanization process of the present invention.

[0028] The diagram shows: 1. Upper template; 2. Middle template; 3. Lower template; 4. Rubber; 5. Fabric clamp; 6. Auxiliary material tray. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. 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.

[0030] To further understand the invention, the technical solution will be further described below in conjunction with specific embodiments.

[0031] Example 1: As Figures 2-5 As shown, this embodiment provides a process suitable for forming rubber-insulated fabric diaphragms.

[0032] The mold comprises a three-layer structure consisting of an upper mold plate 1, a middle mold plate 2, and a lower mold plate 3. The upper mold plate 1 and the lower mold plate 3 are respectively installed on the vulcanizing equipment. The middle mold plate 2 is detachably connected to the upper mold plate 1 and the lower mold plate 3 to facilitate the opening and closing of the mold and the removal of the middle mold plate 2. To ensure that the rubber 4 adheres to the surfaces of the upper mold plate 1 and the lower mold plate 3, several grooves are provided at intervals on the lower surface of the upper mold plate 1 and the upper surface of the lower mold plate 3, which are auxiliary material trays 6. The auxiliary material trays 6 are connected to the upper mold cavity and the lower mold cavity. In this embodiment, the auxiliary material trays 6 are frustoconical in shape, and the opening of the tray is flush with the surface of the mold plate, and the diameter of the opening is smaller than the size of the bottom. The diameter of the bottom is 1-3 mm larger than the diameter of the opening to enhance the adhesion stability of the auxiliary material tray to the mold plate.

[0033] The pre-refined nitrile rubber raw material is injected into the upper and lower cavities of the mold using an injection molding machine. After injection molding, the vulcanization equipment is started, the mold temperature is raised to 160°C, and a pressure of 8 MPa is applied and maintained for 100 seconds for the first vulcanization. During this process, the nitrile rubber 4 flows fully under high temperature and high pressure, completely filling the mold cavity and auxiliary material groove, ensuring that the rubber 4 is evenly distributed.

[0034] After the first vulcanization, the rubber 4 is formed into a stable upper and lower rubber layer that adheres to the mold surface. Simultaneously, an auxiliary material bundle, integrally connected to the rubber layer on the same side, is formed in the auxiliary material bundle groove 6. The mold opening of the vulcanization equipment causes the middle mold 2 and upper mold 1 to move upwards together, separating from the lower mold 3. Subsequently, the middle mold 2 is removed manually or by a robotic arm. During the mold opening process, because the bottom of the groove, far from the mold surface, is wider than the groove opening, the auxiliary material bundle formed in the auxiliary material bundle groove 6 carries the rubber 4 formed in the mold cavity with the mold. The vulcanized rubber 4 in the upper mold cavity remains attached to the upper mold 1 due to adhesion, while the vulcanized rubber 4 in the lower mold cavity adheres to the lower mold 3. Both have formed a stable shape and will not flow or deform. Then, the fabric is manually laid flat on the surface of the rubber 4 on the lower mold 3. During the laying process, a vacuum suction device or scraper removes air between the fabric and the surface of the rubber 4, ensuring that the fabric completely covers the surface of the rubber 4 and adheres tightly without any wrinkles or air bubbles.

[0035] Finally, the upper mold 1 is moved downwards by the mold closing mechanism of the vulcanizing equipment, closing with the lower mold 3. At this point, the rubber on the upper mold 1, the rubber 4 on the lower mold 3, and the fabric together form a molding cavity. The vulcanizing equipment is restarted, maintaining the parameters of 160℃ and 8MPa, and vulcanizing for 230 seconds for a second vulcanization. During the second vulcanization process, the rubber 4 on the upper mold 1 and lower mold 3 further cross-links and tightly bonds with the intermediate fabric 5. After vulcanization, due to the elasticity of rubber, the product with the auxiliary material bundle is removed under external force; by cutting off the auxiliary material bundle, the finished rubber-fabricated film is obtained.

[0036] Example 2: As Figures 2-5 As shown, unlike Example 1, during the first vulcanization, the mold temperature was raised to 157°C, and a pressure of 8.5 MPa was applied and maintained for 95 seconds to improve the performance of rubber 4. During the second vulcanization, the temperature was maintained at 157°C and the pressure at 8.5 MPa for 235 seconds, ensuring that the rubber 4 on the upper mold 1 and lower mold 3 was tightly bonded to the intermediate fabric 5. After vulcanization, the mold was opened to obtain the finished rubber-fabricated film.

[0037] Unlike existing technologies that rely on PTFE coatings to prevent adhesion, this invention employs multiple spaced auxiliary material grooves 6 on the lower surface of the upper mold 1 and the upper surface of the lower mold 3, i.e., on the opposite surfaces of the upper mold 1 and the lower mold 3. The auxiliary material grooves 6 are connected to the mold cavity, so that the auxiliary material is integrally formed with the rubber 4 in the mold cavity during the vulcanization of the rubber 4, achieving stable adhesion of the rubber layer to the upper and lower molds, and avoiding adhesion of the rubber layer when the mold is opened without the need for a special coating.

[0038] It should be noted that, Figures 3-5 The auxiliary material handle (rubber formed in the auxiliary material handle groove) is not shown, but those skilled in the art can clearly and without doubt understand the technical solution described in this invention, and it does not constitute ambiguity or an obstacle for those skilled in the art to understand the technical solution described in this invention.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process for forming rubber-insulated fabric diaphragms, characterized in that, Includes the following steps: S1, place the middle template (2) between the upper template (1) and the lower template (3), and then close the mold for the first time; the upper template (1) and the lower template (3) are provided with auxiliary material grooves (6) on opposite sides, and the upper mold cavity and the lower mold cavity are respectively connected to the auxiliary material grooves (6) on the same side; the groove opening of the auxiliary material groove (6) is flush with the template surface, and the bottom diameter of the groove is larger than the opening diameter; S2, inject the rubber (4) raw material into the upper mold cavity formed between the upper mold plate (1) and the middle mold plate (2), the lower mold cavity formed between the middle mold plate (2) and the lower mold plate (3), and the auxiliary material groove (6). After the injection is completed, perform the first vulcanization. S3, after the rubber (4) is vulcanized, the mold is opened. Then the middle mold (2) is taken out first, and the cloth is laid on the surface of the rubber (4) attached to the lower mold (3). The mold is closed for the second time and the second vulcanization process is carried out. After the vulcanization is completed, the product with auxiliary material is taken out. S4, by cutting off the auxiliary material, a rubber-coated fabric film is obtained.

2. The process for forming rubber-insulated fabric diaphragms according to claim 1, characterized in that, The vulcanization temperature is 160±5℃, and the vulcanization pressure is 8±0.5MPa.

3. The process for forming rubber-insulated fabric diaphragms according to claim 2, characterized in that, The shapes of the upper and lower mold cavities are the same as those of the pre-formed rubber-insulated film.

4. The process for forming rubber-insulated fabric diaphragms according to claim 3, characterized in that, The inner layer of the rubber-insulated diaphragm is made of fabric (5), and the upper and lower surfaces of the fabric (5) are made of rubber (4).

5. The process for forming rubber-insulated fabric diaphragms according to claim 4, characterized in that, The first vulcanization time is 100±10 seconds.

6. The process for forming rubber-insulated fabric diaphragms according to claim 5, characterized in that, The second vulcanization time is 230±10 seconds.

7. The process for forming rubber-insulated fabric diaphragms according to claim 1, characterized in that, The temperature and pressure of the first vulcanization are the same as those of the second vulcanization.

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