JP2007021943A - Manufacturing method of sealing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a sealing material capable of manufacturing a sealing material of a high quality while achieving an improved production efficiency and a reduced cost. <P>SOLUTION: The manufacturing method of the sealing material includes a process of obtaining an unvulcanized rubber shaped body by shaping an unvulcanized synthetic rubber material, a process of applying fluororesin-based coating on at least a part of the surface of the unvulcanized rubber shaped body, and a process of obtaining an elastic rubber shaped body by vulcanizing the unvulcanized rubber by heating the unvulcanized rubber shaped body on which the fluororesin-based coating is applied and forming a coating layer on the surface of the elastic rubber shaped body by heating and fixing the fluororesin-based coating. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a sealing material in which a fluororesin-based coating layer is formed on the surface of an elastic rubber molded body.

  In the case where the opening of a building, vehicle, various devices, etc. is opened and closed by an opening / closing member such as a window, door, sliding door, shoji, etc., the watertightness in the gap between the opening / closing member and the opening frame, Usually, an elastic sealing material is provided so as to ensure airtightness, heat insulation, soundproofing and the like. This sealing material is provided on any one of the opening / closing member and the opening frame, and the sealing material is slidably brought into contact with the other member, whereby the space between them is sealed.

  For example, in a building sash, an elastic sealing material is attached to a predetermined position of the opening frame, and a part of the sealing material (lip part) is slidably contacted with an opening / closing member such as a shoji or a door to seal between the two. Like to do.

  Conventionally, this type of sealing material is made of an elastic material such as synthetic rubber. Since this synthetic rubber sealing material is one in which the lip portion (sliding contact portion) is in sliding contact with the opening and closing member, if the contact pressure is increased, the sealing performance can be improved, but the frictional resistance increases. Opening and closing cannot be performed smoothly, and it becomes difficult to perform operability during opening and closing smoothly. In particular, when the lip portion of the sealing material is left in contact with the opening / closing member with a strong pressure for a long period of time, the lip portion of the sealing material adheres to the opening / closing member, and the operation of the opening / closing member is further improved. May be even more difficult.

  Conversely, if the contact pressure of the sealing material on the opening / closing member is weakened, the frictional resistance at the time of opening / closing is reduced, and the opening / closing can be performed smoothly. There is a risk of damage.

Therefore, as shown in Patent Documents 1 and 2 below, a technique has been proposed in which a lip portion of a sealing material is covered with a fluororesin. In this fluorine-coated sealant, the frictional resistance is small even when the lip portion is brought into strong contact with an opening / closing member such as a shoji or a door, so that it can be easily opened and closed, and a good sealing property is secured. be able to.
Japanese Utility Model Publication No. 52-126642 (claims 1-3) JP-A-10-231668 (Claim 5)

  Conventionally, when producing a fluorine-coated type sealing material as described above, an unvulcanized synthetic rubber material is extruded to produce an unvulcanized rubber molded body. Elastic rubber products are manufactured by heat vulcanization. Subsequently, after applying a fluororesin-based paint to the elastic rubber product, the fluororesin-based paint is dried and solidified by heating to form a fluororesin-based coating layer on the surface of the elastic rubber product.

  However, in the above conventional sealing material manufacturing method, the process of manufacturing the elastic rubber product and the process of forming the coating layer are performed separately and independently, so that the product is transferred between the processes. There was a problem that it could not be performed smoothly, the production efficiency was lowered, and the cost was increased. Furthermore, since the two steps are performed separately, sharing between the two steps cannot be performed at all, and there arises a problem that the production efficiency is further reduced and the cost is further increased.

  In addition, the conventional sealing material manufacturing method applies heat twice during vulcanization when manufacturing an elastic rubber product and during paint curing when forming a coating layer. Thus, there has been a problem that the physical properties of the rubber product are lowered due to thermal deterioration (heat aging).

  Furthermore, in the conventional method for producing a sealing material, since the compounding component is deposited by blooming on the surface of the elastic rubber product obtained by heat vulcanization, the deposited component is interposed between the rubber product surface and the coating layer. As a result, the adhesion of the coating layer becomes insufficient. Accordingly, the coating layer is likely to be peeled off, which also has a problem of reducing the quality of the sealing material product.

  An object of the present invention is to provide a manufacturing method of a sealing material that can solve the above-described problems of the prior art and obtain a high-quality sealing material while improving production efficiency and reducing costs.

  In order to achieve the above object, the present invention is summarized as follows.

[1] A step of molding an unvulcanized synthetic rubber material to obtain an unvulcanized rubber molded body;
Applying a fluororesin-based paint to at least a part of the surface of the unvulcanized rubber molded body;
By heating an unvulcanized rubber molded body coated with a fluororesin-based paint, an unvulcanized rubber is vulcanized to obtain an elastic rubber molded body, and the fluororesin-based paint is heated and fixed to form an elastic rubber molded body. And a step of forming a coating layer on the surface of the sealing material.

  [2] The method for producing a sealing material according to item 1 above, wherein a composition containing polytetrafluoroethylene (PTFE) powder, a resin binder and a solvent is used as the fluororesin paint.

  [3] The method for producing a sealing material according to item 1 or 2, wherein ethylene propylene rubber (EPDM) or chloroprene rubber (CR) is used as the synthetic rubber material.

  According to the manufacturing method of the sealing material of the invention [1], the heating process at the time of vulcanizing the synthetic rubber and the heating process at the time of curing the fluororesin-based paint are shared by one heating process. As a result, the production efficiency can be improved and the cost can be reduced.

  Furthermore, since the molding process, paint coating process, and heating process that constitute the manufacturing method of the present invention can be performed continuously in a series of processes, the product can be transferred between the processes without stagnation between the processes. This can be performed smoothly, and the production efficiency can be further improved and the cost can be reduced.

  In addition, since the heating process only needs to be performed once, the amount of heat received is reduced, thermal degradation is suppressed, and high quality as a rubber product can be obtained.

  Further, since the vulcanization of the synthetic rubber and the curing of the resin coating are performed in parallel, the resin coating is fixed on the rubber surface before the compounding components are precipitated on the rubber surface by blooming during vulcanization. Accordingly, it is possible to prevent the precipitation component from interposing between the rubber surface and the coating layer, to improve the adhesion of the coating layer, and to obtain a higher quality.

  According to the manufacturing method of the sealing material of the invention [2] and [3], the above effect can be obtained more reliably.

  FIG. 1 is a block diagram showing a manufacturing process in a method for manufacturing a sealing material according to an embodiment of the present invention. As shown in the figure, the manufacturing method of the present embodiment includes a process of extruding an unvulcanized synthetic rubber material to obtain an unvulcanized rubber molded body (extrusion molding process), and a fluorine in the unvulcanized rubber molded body. Applying resin-based paint (paint application process) and unvulcanized rubber molding with fluororesin-based paint heated by microwave heating and hot air heating to vulcanize synthetic rubber and at the same time fluororesin-based A step of curing the coating material (heating step).

  In the present embodiment, the synthetic rubber material includes ethylene propylene rubber (EPDM), chloroprene rubber (CR), butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), styrene butadiene rubber (SBR), acrylic rubber (ACR), Urethane rubber (U) or the like can be used, and among them, EPDM, CR, NBR, and U can be preferably used.

  EPDM and CR are preferably used as rubber materials especially when used as a sealing material for gaps between openings in buildings such as houses and opening and closing members such as windows, doors, and sliding doors that open and close the openings. Can do. That is, these rubber materials are excellent in deterioration resistance such as weather resistance and ozone resistance, and can be used for a long period of time as a sealing material for a frame member while maintaining good physical properties.

  In the present embodiment, additives usually used such as a vulcanizing agent, a vulcanization accelerator, an anti-aging agent, a reinforcing agent, a filler, a plasticizer, and the like are appropriately added to the above-described synthetic rubber material for molding. Rubber material.

  The rubber material thus obtained is extruded to produce an unvulcanized rubber molded body having a predetermined cross-sectional shape.

  Subsequently, a fluororesin-based paint is applied to at least a part of the surface of the unvulcanized rubber molded body, that is, a portion (sliding contact portion, lip portion, etc.) in sliding contact with the opening / closing frame or the opening / closing member.

  In the present embodiment, as the fluororesin-based paint, a composition in which a fluororesin powder and a resin binder are blended in a solvent in a dispersed state can be suitably used.

  As the fluororesin, polytetrafluoroethylene (PTFE) resin or the like can be suitably used.

  The molecular weight of the PTFE resin powder used as the fluororesin in this embodiment is not particularly limited, but 1,000 to 10,000,000 can be used, and preferably 10,000 to 5,000,000. Good to use.

  The PTFE resin powder is applied in a state of being dispersed in a solvent. As a dispersion method, it is possible to disperse in a solvent using a surfactant or use a dispersion obtained by emulsion polymerization. it can.

  The amount of the PTFE resin powder in the coating composition is set to 1 to 50% by weight, preferably 1 to 40% by weight, more preferably 1 to 20% by weight as a solid component. That is, when the blending amount of the PTFE resin powder is too small (less than 1% by weight), it is difficult to obtain a good friction reducing effect on the produced sealing material. Conversely, when the amount of PTFE resin powder is too large (over 40% by weight), the film-forming property is poor, for example, the coating layer becomes too hard, and peeling and cracking are likely to occur, and the cost is increased. Therefore, it is not preferable.

  As the resin binder, acrylic resin, epoxy resin, polyurethane, vinyl acetate, phthalic acid, polyester, melamine, and acrylic urethane can be used. Among them, an elastomeric material, particularly a material excellent in compatibility with a fluororesin (base material) can be preferably used.

  The blending amount of the resin binder in the coating composition is set to 1 to 60% by weight, preferably 3 to 50% by weight, more preferably 5 to 45% by weight as a solid component. If the amount of the resin binder is too large or too small, the amount of PTFE resin powder is relatively increased or decreased, and the above-described problem may occur.

  As the solvent, an organic solvent or water is usually used.

  In addition, you may mix | blend additives, such as a drying regulator, a thickener, a rust preventive agent, a pigment, and an antistatic agent, with a coating composition as needed.

  The coating composition may be prepared by stirring and mixing the PTFE resin powder and the resin binder simultaneously with the solvent, or after kneading the PTFE resin powder into the resin binder and diluting with the solvent. It may be prepared.

  Conventionally used methods such as spray coating, brush coating, roller coating, and dipping are used as the method for applying the coating composition to the unvulcanized rubber molded body. When the coating method is used, it can be uniformly applied to the application region, and a good coating film (coating layer) having a uniform thickness can be formed.

  In this embodiment, by heating the unvulcanized rubber molded body to which the paint is applied, the unvulcanized rubber is vulcanized, and at the same time, the paint is heated and fixed to form a fluororesin-based coating layer. is there.

  In this embodiment, as shown in FIG. 1, in the heating step, the unvulcanized rubber molded body with paint is successively subjected to microwave heating in the UHF tank and hot air heating in the HAV tank in sequence. .

  Here, in the present embodiment, the heating conditions are set in consideration of the vulcanization temperature of the synthetic rubber material and the curing temperature of the fluororesin-based paint.

  For example, in this embodiment, the heating temperature is set to a temperature range in which both the vulcanization temperature of the synthetic rubber material and the curing temperature of the fluororesin-based paint are included. In other words, in the present embodiment, the synthetic rubber material and the fluororesin-based paint are preferably configured so that the vulcanization temperature of the synthetic rubber material and the curing temperature of the fluororesin-based paint are approximated.

  Here, in this embodiment, when chloroprene rubber is used as the synthetic rubber material, since the vulcanization temperature is 140 to 180 ° C., a fluororesin-based paint that cures at a temperature close to the vulcanization temperature is used. Is preferred. Specifically, a fluororesin-based paint having a curing temperature (drying and solidification temperature) of 200 ° C. or lower, preferably 140 to 160 ° C. may be used. In general, fluororesin-based paints are usually of a type that cures at 200 to 350 ° C. However, the above-mentioned fluororesin-based paints composed of PTFE resin and resin binder cure at 200 ° C. or less in the above-mentioned suitable temperature range. Therefore, the use of this paint is desired.

  In this embodiment, by heating the unvulcanized rubber molded body with the paint, the unvulcanized rubber is vulcanized to form an elastic rubber molded body. At the same time as the vulcanization, the paint is dried and solidified. Thus, a fluororesin-based coating layer is formed on the surface of the elastic rubber molded body.

  Here, the thickness of the coating layer after curing is preferably adjusted to 3 to 30 μm, preferably 5 to 20 μm, more preferably 7 to 15 μm. That is, when this film thickness is too thin, it becomes difficult to control the film thickness, and a film cannot be formed uniformly over a wide range, and there is a possibility that a sufficient friction reducing effect cannot be obtained. On the other hand, when the film thickness is too thick, problems such as peeling of the film may occur, which is not preferable.

  Further, the rubber hardness of the elastic rubber molded body (elastic rubber product) after vulcanization is preferably adjusted to 50 to 70 ° (JIS A hardness). That is, when the rubber hardness is less than 50 °, the rubber is too soft and elastic deformation is increased, which may make it difficult to obtain a good sealing property (sealing property) as a sealing material. On the other hand, if it exceeds 70 °, it becomes too hard and the elastic deformation becomes extremely poor, and it may be difficult to obtain a good sealing property (sealing property) as a sealing material, which is not preferable.

  In the manufacturing method of the sealing material in the present embodiment described above, the heating process at the time of vulcanizing the synthetic rubber and the heating process at the time of curing the fluororesin-based paint are shared by one heating process. Compared with the case where the heating process is performed separately, the number of processes can be reduced, and the production efficiency can be improved correspondingly, and the cost can be reduced.

  Furthermore, in the present embodiment, the extrusion molding process, the paint application process, and the heating process can be continuously performed in a series of processes. For example, an elastic rubber molded body manufacturing process, a fluororesin-based coating layer forming process, Compared to those that are performed independently of each other, products can be smoothly transferred between processes without delaying products between processes, and production efficiency and costs can be further reduced. Can do.

  Further, in this embodiment, since the vulcanization of the synthetic rubber and the curing of the fluororesin are performed at the same time, only one heating is required, the amount of heat received is reduced, the heat aging is suppressed, and the rubber product is good. Physical properties can be obtained.

  In this embodiment, before the synthetic rubber is vulcanized, the resin coating for the coating layer is applied to the rubber surface, and the vulcanization of the synthetic rubber and the curing of the resin coating are performed simultaneously. High adhesion to the layer can be obtained. That is, before the compounding components are deposited on the rubber surface by blooming during vulcanization, the resin coating is fixed on the rubber surface, thereby preventing the compounding components from precipitating on the rubber surface. Therefore, the coating layer can be directly attached to the substrate without any impurities (deposited components), high adhesion can be obtained, and defects such as peeling of the coating layer can be effectively prevented.

  Hereinafter, the Example relevant to this invention and the comparative example compared with the Example are described in detail.

<Example 1>
As shown in Table 1, as a synthetic rubber material, a chloroprene rubber (CR) polymer (50% by weight) is blended with a predetermined additive (50% by weight) such as a vulcanizing agent and kneaded. The material was extruded using an extruder to obtain a band-shaped (tape-shaped) unvulcanized rubber molded body having a thickness of 1.2 mm and a width of 10 mm.

  Next, on one surface of this unvulcanized rubber molded body, PTFE resin powder (3.0 wt% in solid component) as a fluororesin, urethane binder (10 wt% in solid component) as a resin binder, solvent A fluorine resin paint containing and was applied by spray coating. The coating amount was adjusted so that the film thickness after drying was 10 μm.

  The unvulcanized rubber molded body with paint thus obtained was subjected to continuous microwave heating in the UHF tank and hot air heating in the HAV tank. At this time, it heated at 200 degreeC by microwave heating for 1 minute, and heated at 160 degreeC for 20 minutes by hot air heating. As a result, an unvulcanized rubber is thermally vulcanized to obtain an elastic rubber molded body, and at the same time, the fluororesin-based paint is dried and solidified (heated and stabilized) to form a fluorine resin-based coating layer on one surface (surface) of the elastic rubber molded body (Coating) was formed, and a sealant sample was manufactured.

<Example 2>
As shown in Table 1, as a synthetic rubber material, an ethylene propylene rubber (EPDM) polymer (55% by weight) is blended with an additive (45% by weight) and the compounded rubber material is used with an extruder. And extruded to obtain an unvulcanized rubber molded body having the same shape as described above.

  Next, on one surface of this unvulcanized rubber molded body, PTFE resin powder (3.0 wt% in solid component) as a fluororesin, urethane binder (10 wt% in solid component) as a resin binder, solvent A fluorine resin paint containing and was applied by spray coating. The coating amount was adjusted so that the film thickness after drying was 18 μm.

  The thus obtained unvulcanized rubber molded body with paint was heated at 200 ° C. for 2 minutes by microwave heating, and subsequently heated at 160 ° C. for 25 minutes by hot air heating. As a result, the unvulcanized rubber was thermally vulcanized, and at the same time, the fluororesin-based paint was cured to produce a sealing material sample.

<Example 3>
As shown in Table 1, as a synthetic rubber material, an acrylonitrile butadiene rubber (NBR) polymer (45% by weight) is blended with an additive (55% by weight), and the compounded rubber material is used with an extruder. And extruded to obtain an unvulcanized rubber molded body having the same shape as described above.

  Next, on one surface of this unvulcanized rubber molded body, PTFE resin powder (3.0 wt% in solid component) as a fluororesin, urethane binder (10 wt% in solid component) as a resin binder, solvent A fluorine resin paint containing and was applied by spray coating. The coating amount was adjusted so that the film thickness after drying was 25 μm.

  The thus obtained unvulcanized rubber molded body with paint was heated at 200 ° C. for 1 minute by microwave heating, and then heated at 150 ° C. for 20 minutes by hot air heating. As a result, the unvulcanized rubber was thermally vulcanized, and at the same time, the fluororesin-based paint was cured to produce a sealing material sample.

<Example 4>
As shown in Table 1, as a synthetic rubber material, an additive (35% by weight) is blended with a polymer (65% by weight) of urethane rubber (U) and kneaded. Extrusion molding was performed to obtain an unvulcanized rubber molded body having the same shape as described above.

  Next, on one surface of this unvulcanized rubber molded body, PTFE resin powder (3.0 wt% in solid component) as a fluororesin, urethane binder (10 wt% in solid component) as a resin binder, solvent A fluorine resin paint containing and was applied by spray coating. The coating amount was adjusted so that the film thickness after drying was 5 μm.

  The thus obtained unvulcanized rubber molded body with paint was heated at 200 ° C. for 2 minutes by microwave heating, and subsequently heated at 160 ° C. for 30 minutes by hot air heating. As a result, the unvulcanized rubber was thermally vulcanized, and at the same time, the fluororesin-based paint was cured to produce a sealing material sample.

<Comparative Example 1>
Using the synthetic rubber material having the same composition as in Example 1, an unvulcanized rubber molded body was obtained in the same manner, and then the unvulcanized rubber molded body was subjected to microwave heating in the UHF tank and hot air in the HAV tank. Heating was performed continuously. At this time, it heated at 200 degreeC by microwave heating for 1 minute, and heated at 160 degreeC for 20 minutes by hot air heating. Thereby, the unvulcanized rubber was heat vulcanized to obtain an elastic rubber molded body.

  Subsequently, a fluororesin-based paint having the same composition as that of Example 1 was applied to one surface of the elastic rubber molded body to the same thickness by spray coating.

  Then, the elastic rubber molding with paint is heated at 160 ° C. for 30 minutes to cure the paint, thereby forming a fluororesin-based coating layer on the surface of the elastic rubber molding and producing a sealing material sample. did.

<Comparative example 2>
Using a synthetic rubber material having the same composition as in Example 2, an unvulcanized rubber molded body was obtained in the same manner, and then the unvulcanized rubber molded body was heated at 200 ° C. for 2 minutes by microwave heating. It heated at 160 degreeC by hot-air heating for 25 minutes. Thereby, the unvulcanized rubber was heat vulcanized to obtain an elastic rubber molded body.

  Subsequently, a fluororesin-based paint having the same composition as that of Example 2 was applied to one surface of the elastic rubber molded body to the same thickness by spray coating.

  Then, the elastic rubber molding with paint is heated at 160 ° C. for 30 minutes to cure the paint, thereby forming a fluororesin-based coating layer on the surface of the elastic rubber molding and producing a sealing material sample. did.

<Comparative Example 3>
Using the synthetic rubber material having the same composition as in Example 3, an unvulcanized rubber molded body was obtained in the same manner, and then the unvulcanized rubber molded body was heated at 200 ° C. for 1 minute by microwave heating. It heated at 150 degreeC by hot-air heating for 20 minutes. Thereby, the unvulcanized rubber was heat vulcanized to obtain an elastic rubber molded body.

  Subsequently, a fluororesin-based paint having the same composition as in Example 3 was applied to one surface of the elastic rubber molded body to the same thickness by spray coating.

  Then, the elastic rubber molding with paint is heated at 160 ° C. for 30 minutes to cure the paint, thereby forming a fluororesin-based coating layer on the surface of the elastic rubber molding and producing a sealing material sample. did.

<Comparative example 4>
Using a synthetic rubber material having the same composition as in Example 4, an unvulcanized rubber molded body was obtained in the same manner, and then the unvulcanized rubber molded body was heated at 200 ° C. for 2 minutes by microwave heating, and then Heating was performed at 160 ° C. for 30 minutes by hot air heating. Thereby, the unvulcanized rubber was heat vulcanized to obtain an elastic rubber molded body.

  Subsequently, a fluororesin-based paint having the same composition as that of Example 4 was applied to one surface of the elastic rubber molded body to the same thickness by spray coating.

  Then, the elastic rubber molding with paint is heated at 160 ° C. for 30 minutes to cure the paint, thereby forming a fluororesin-based coating layer on the surface of the elastic rubber molding and producing a sealing material sample. did.

<Evaluation>
Each sealing material sample manufactured as described above was bent several tens of times under the same conditions, and the tape was peeled off to observe the peeling state of the coating layer. Then, “◯” indicates that no peeling was observed, “Δ” indicates that peeling was slightly observed, and “×” indicates that large peeling was observed. The evaluation results for each sample are shown in Table 2.

  As is apparent from Table 2, in the samples of Examples 1 to 4 related to the present invention, the coating layer was firmly adhered in a stable state. In particular, in the samples of Examples 1 and 2, no peeling was observed in the coating layer, and a higher quality sealing material could be obtained.

  In the samples of Comparative Examples 1 to 4 that depart from the gist of the present invention, peeling was observed in the coating layer. Here, in the sealing material of the comparative example, the low adhesion of the coating layer is considered to be caused by heat vulcanization of the synthetic rubber before forming the coating layer. That is, when the unvulcanized rubber is vulcanized, the blended components are deposited and adhered to the rubber surface by blooming. Since this deposited component is difficult to remove reliably from the surface of the rubber molded body, in the comparative example, the fluororesin-based paint is applied and cured with the deposited component still attached to the surface of the rubber molded body. Thus, a coating layer is formed. That is, it is considered that the adhesion of the coating layer is reduced because impurities (deposited components) are interposed between the base material (synthetic rubber) and the coating layer.

  On the other hand, in the sealing materials of Examples 1 to 4 related to the present invention, before the synthetic rubber is vulcanized, a resin coating for the coating layer is applied to the rubber surface, and the synthetic rubber is vulcanized and the resin is vulcanized. The coating is cured simultaneously. For this reason, it is possible to prevent the compounding component from being deposited on the surface of the base material (synthetic rubber) by fixing the resin coating on the rubber surface before the compounding component is deposited on the rubber surface by blooming during vulcanization. it can. Accordingly, since the coating layer is directly attached to the base material without any impurities (deposited components), high adhesion can be obtained.

  On the other hand, the sealing materials of Comparative Examples 1 to 4 have lower physical properties such as elasticity and flexibility than the sealing materials of Examples 1 to 4, and it is considered that there is a problem in durability. This is because the sealing materials of Comparative Examples 1 to 4 apply heat twice during vulcanization and when the fluororesin is cured, so the amount of heat increases, and the physical properties of the rubber product decrease due to thermal degradation. It is thought to do.

  On the other hand, since the sealing materials of Examples 1 to 4 perform vulcanization of the synthetic rubber and curing of the fluororesin at the same time, the heating process only needs to be performed once, and the amount of heat received is small, resulting in thermal deterioration. Is suppressed, and good physical properties of the rubber product can be maintained over a long period of time.

It is a block diagram which shows the manufacturing process in the manufacturing method of the sealing material which is embodiment of this invention.

Claims (3)

A step of molding an unvulcanized synthetic rubber material to obtain an unvulcanized rubber molded body;
Applying a fluororesin-based paint to at least a part of the surface of the unvulcanized rubber molded body;
By heating an unvulcanized rubber molded body coated with a fluororesin-based paint, an unvulcanized rubber is vulcanized to obtain an elastic rubber molded body, and the fluororesin-based paint is heated and fixed to form an elastic rubber molded body. And a step of forming a coating layer on the surface of the sealing material.   The method for producing a sealing material according to claim 1, wherein a composition containing polytetrafluoroethylene (PTFE) powder, a resin binder, and a solvent is used as the fluororesin paint.   The method for producing a sealing material according to claim 1 or 2, wherein ethylene-propylene rubber (EPDM) or chloroprene rubber (CR) is used as the synthetic rubber material.

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