JPH07227935A - Rubber-based composite material and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a rubber-based composite material, which maintains rubbery elasticity and at the surface of which a fluoroplastic fiber layer excellent in various performances such as slipperiness, chemical resistance or the like and having excellent adhesion without employing an adhesive is provided. CONSTITUTION:A rubber-based composite material consists of a rubber base 10 and a fluoroplastic fiber layer 11, which is integrally bonded with the rubber base 10 through the impregnation of the rubber in the rubber base 10 formed on the surface of the rubber base 10 in the layer. By compression-molding the rubber base under the condition that the fluoroplastic fibrous body is arranged in a mold, the rubber fluidized at vulcanizing is infiltrated in the voids of the fluoroplastic fibrous body for vulcanization, resulting in integrally bonding the fluoroplastic resin layer 11 with the rubber base 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber-based composite material having a fluororesin layer on the surface of a rubber substrate and a method for producing the same.
The rubber-based composite material of the present invention has the elasticity of rubber and the slidability of fluororesin, chemical resistance, corrosion resistance, heat resistance, etc., so that it can be used in various fields such as sealing materials such as packings and seal rings, and cushioning materials. Available.

[0002]

2. Description of the Related Art Vulcanized rubber parts are widely used as sealing materials, cushioning materials, etc. by utilizing their elasticity. However, general vulcanized rubber has excellent elasticity, but has a large friction coefficient and low slidability. Then, a sticking phenomenon may occur due to a reaction at an interface with a contacting counterpart component, and there is also a problem that the material used is limited.

Further, general vulcanized rubber is not sufficient in various properties such as chemical resistance and heat resistance. For this reason, fluororubber is mainly used at the site where chemical resistance and heat resistance are required, but there is a drawback that the fluororubber is expensive. Further, fluororubber is apt to cause a sticking phenomenon with, for example, brass, and is not used for packing of a reservoir tank cap of an automobile.

Therefore, as a method of imparting slidability, chemical resistance or heat resistance to a vulcanized rubber, it has been proposed to combine a vulcanized rubber and a fluororesin. For example, JP 1-12
Japanese Patent No. 0484 discloses a seal packing formed by adhering and laminating a fluororesin film on a ring-shaped seal packing material, and a manufacturing method thereof. In the manufacturing method disclosed in Japanese Patent Laid-Open No. 1-120484, first, a ring-shaped seal packing material is vulcanized and molded from nitrile rubber or the like, and then a fluorine resin film formed in a predetermined shape in advance has a silane coupling material or phenol. The seal packing is manufactured by pressurizing and heating the seal packing material using a system adhesive.

As other methods for imparting slidability to the vulcanized rubber, a method of increasing the rubber hardness of the sliding portion, a method of breaming or bleeding a specific rubber compound on the sliding surface, a fluororesin coating, etc. It is also known how to do.

[0006]

However, the fluororesin has extremely poor adhesiveness, and even with the seal packing obtained by the manufacturing method disclosed in JP-A 1-120484, the bonding strength of the fluororesin film is not sufficient. I couldn't say it. There is also a problem that an adhesive is essential and the number of steps is large.

Further, in the method of increasing the rubber hardness of the sliding portion, the original elasticity of the rubber is lowered and it is difficult to secure the performance balance. In addition, the method of bleaming and bleeding the rubber compound has problems in effect persistence and appearance quality, and the coating method also has a problem in adhesiveness, so that an adhesive must be used. The present invention has been made in view of such circumstances, having a fluororesin fiber layer excellent in various properties such as slidability and chemical resistance on the surface while maintaining the elasticity of rubber,
The fluororesin fiber layer is intended to provide a rubber-based composite material having excellent adhesiveness without using an adhesive.

[0008]

The rubber-based composite material of the present invention which solves the above-mentioned problems is integrally bonded to a rubber substrate by impregnating the rubber substrate formed on the surface of the rubber substrate with the rubber of the rubber substrate. And a fluororesin fiber layer. As the rubber substrate, natural rubber (NR), synthetic natural rubber (IR), styrene-butadiene rubber (SB
R), butadiene rubber (BR), butyl rubber (II
R), nitrile rubber (NBR), ethylene / propylene rubber (EPM, EPDM), acrylic rubber (ACM, A)
NM), chloroprene rubber (CR), fluororubber (FK
Any rubber having rubber elasticity such as M) can be used regardless of its type.

The fluororesin fibers constituting the fluororesin fiber layer can be arranged in various forms such as felt, woven cloth, paper or a shape in which single fibers are randomly arranged. From the viewpoint of strength, it is preferable to use paper or woven cloth as will be described later. The production method of the present invention for producing this rubber-based composite material comprises arranging a fiber made of a fluororesin on the surface of a base material made of an unvulcanized rubber, and applying pressure to impregnate the unvulcanized rubber between the fibers. It is characterized in that the base material is vulcanized and the fibers are integrally bonded to the base material.

By arranging the fiber made of fluororesin in the form of woven cloth or paper, it can be easily arranged on the surface of the base material made of unvulcanized rubber. Then, by heating under pressure, the rubber flows and penetrates into the minute gaps between the fibers, and the fibers are bonded by vulcanization. As a result, the fiber is mechanically and integrally bonded to the base rubber, and exhibits the characteristics of the fiber itself.

In the rubber-based composite material thus obtained, the fluororesin fiber layer contains rubber impregnated between the fibers, and the rubber may not fully exhibit the characteristics of the fluororesin fiber layer. . Therefore, the further improved rubber-based composite material of the present invention comprises a rubber base, a fluororesin fiber layer formed on the surface of the rubber base and integrally bonded to the rubber base by impregnating the rubber of the rubber base, and a fluororesin. And a fluororesin layer integrally laminated on the surface of the fiber layer.

Although the fluororesin has extremely low adhesion to other substances, high adhesion can be obtained if the fluororesins are used together. Therefore, when the fluororesin layer is formed on the surface of the fluororesin fiber layer of the rubber-based composite material of the first invention, the fluororesin layer is bonded to the fluororesin fiber layer with high bonding strength by welding or adhesion. The fluororesin fiber layer is mechanically bonded to the rubber substrate with high strength. Therefore, the three layers are firmly bonded. Further, since the surface has the fluororesin layer, the characteristics of the fluororesin are maximized.

[0013]

In the rubber-based composite material of the present invention, the fluororesin fiber layer is mechanically and integrally bonded to the rubber substrate. Here, since the fluororesin fiber layer is a group of fibers, it has a high degree of freedom of deformation and easily deforms following the deformation of the rubber substrate.
Therefore, the fluororesin fiber layer hardly interferes with the rubber elasticity, and the elasticity of the rubber substrate itself can be obtained.

Further, since the fluororesin fiber layer is exposed on the surface, it is possible to obtain the characteristics such as the slidability, chemical resistance and corrosion resistance of the fluororesin. Further, in the method for producing a rubber-based composite material of the present invention, high bonding strength can be obtained simply by placing the fluororesin fiber on the surface of the unvulcanized rubber substrate, pressurizing and heating and vulcanizing, and no adhesive is required. Is. Therefore, it is possible to manufacture with high productivity and stable quality. When the fluororesin fiber is used as a papermaking body, the placing step is easy, and the three-dimensional papermaking makes it possible to easily deal with a complicated shape.

Further, when the fluororesin layer is formed on the surface of the fluororesin fiber layer, the rubber substrate and the fluororesin fiber layer and the fluororesin fiber layer and the fluororesin layer are bonded together with high strength, so that the overall bonding is high. It is possible to maximize the characteristics of the fluororesin while ensuring the strength.

[0016]

EXAMPLES The present invention will be specifically described below with reference to examples. First, each compound was mixed in the following composition to prepare an unvulcanized compounded rubber. EPDM 100 parts by weight Carbon black 40 parts by weight Amine-based antioxidant 1 part by weight Benzimidazole-based antioxidant 1 part by weight Processing aid (fatty acid ester-based processing aid) 3 parts by weight Filler (calcium carbonate) 10 parts by weight Addition Sulfurizing agent (P / O (dicumyl peroxide) 6 parts by weight) Next, a tetrafluoroethylene resin fiber is formed by papermaking, and has a thickness of 0.5 to 1 mm and a porosity of 75 vol%. "Polyflon paper PA-5L" manufactured by Daikin Industries, Ltd. was prepared, and it was placed along the mold surface of the molding die, and 100 kg of the unvulcanized compounded rubber was used as a raw material.
Compression molding was carried out by heating under pressure of f / cm ² at 175 ° C. for 10 minutes to obtain a flat rubber-based composite material.

A schematic cross-sectional view of the obtained rubber-based composite material is shown in FIG. 1, and photomicrographs of the cross-section are shown in FIG. 2 (× 100) and FIG.
(× 300). This rubber-based composite material 1 is EPDM
It is composed of a rubber base 10 made of rubber and a fluororesin fiber layer 11, and the rubber of the rubber base 10 penetrates into the pores of the fluororesin fiber layer 11 and is vulcanized. The resin fiber layer 11 is integrally connected.

This rubber-based composite material was subjected to a bending test as follows, and the sliding resistance, fixing force and adhesive strength were measured. (1) Bending test The obtained rubber-based composite material was subjected to a rebound resilience test by Lupke and a surface condition observation by 180 ° bending. Further, as a comparison, an EPDM plate formed in the same manner as above except that the fluororesin fiber body was not used was similarly tested.

As a result, the decrease in rubber elasticity (repulsion elasticity) due to the formation of the fluororesin layer 11 is about 5%,
Further, it was found that the surface crack state due to the 180 ° bending was not observed, and the compression and extension stresses due to the bending were sufficiently followed. Therefore, the rubber-machine composite material of this example has sufficient rubber elasticity. It is clear that (2) Sliding resistance As shown in FIG. 4, the rubber-based composite material 1 is placed on the horizontal base 3 with the fluororesin fiber layer 11 facing upward, and a weight 30 of 200 g is put on the fluororesin fiber layer 11. Place the watch glass 31. Then, using the load cell 32, set the watch glass 31 to 20
It was pulled horizontally at a speed of 0 mm / min, and the surface resistance value and sliding pattern were measured by an autograph. In addition, an EPDM plate formed in the same manner as above except that the fluororesin fiber body was not used was also measured in the same manner.
And shown in FIG.

[0020]

[Table 1] From Table 1 and FIG. 5, the EPDM plate has a high surface resistance and the sliding pattern shows stick-slip, whereas the rubber-based composite material of this example has a very small sliding resistance and smooth and stable sliding. It is clear that it shows a pattern. (3) Fixing force The shape of the rubber-based composite material is set to 20 mm × 20 mm × 2 mm, and it is sandwiched between two brass plates having a shape of 25 mm × 35 mm × 4 mm and fixed, and then a tensile test is performed to make the fluororesin fiber layer 11 The strength required to peel off the brass plate was measured and used as the adhesive strength.

The surface of the rubber-based composite material was degreased with ethanol, and then a long life coolant 100% liquid was applied to both surfaces. The brass plate was polished with # 400 sandpaper and then with # 1000 sandpaper, and then ethanol. It was washed with and used. As shown in FIG. 6, the rubber-base composite material and the brass plate are fixed to each other under a compression load of 17.7 k by the spring 4.
Press the brass plates 40, 41 and the rubber-based composite material 1 with gf,
In an atmosphere filled with a 30 wt% aqueous solution of long-life coolant, the temperature was maintained at 120 ° C. in a pressurized state to deteriorate for 70 hours. After the deterioration, the pressure was further maintained at room temperature for 24 hours to remove the load, and then a tensile test was performed. Tensile speed is 20mm / min, temperature is room temperature (23 ℃)
I went there. The number of samples is n = 2.

An EPDM plate, an NBR plate, and an S formed in the same manner as above except that the fluororesin fiber body is not used.
The BR plate and the FKM plate were similarly measured, and the results of both are shown in Table 2.

[0023]

[Table 2] From Table 2, it is clear that the rubber-based composite material of this example has a markedly reduced sticking to the brass plate as compared with general rubber materials. Therefore, if this rubber-based composite material is used as the packing of the reservoir tank cap, the sticking can be prevented for a long time and the life can be extended. (4) Adhesive Strength A compression-molded product having a strip shape of 100 mm × 10 mm was used, a fluororesin fiber body similar to the above was placed on the mold surface, and then compression molding was similarly performed using EPDM. It was At this time, molding was carried out by masking the space between the fluororesin fiber body and the EPDM with a high-density polyethylene resin only in the half portion in the longitudinal direction. Therefore, in the obtained test piece, the rubber-based composite material is formed only in the longitudinal half, and the other half extends from the rubber-based composite material in a state where the rubber substrate and the fluororesin fiber body are separated.

Using this test piece 6, as shown in FIG. 7, a pair of chucks 50, 51 are separated into a rubber substrate 60.
And the fluororesin fiber body 61 are gripped respectively, and 20 mm
The adhesive strength was measured by measuring the tensile strength when the film was pulled 180 degrees in the opposite direction at a speed of / minute. The number of samples is n = 5.
A two-component adhesive (“P-6-1, 81
4-1 "manufactured by Sixon Co., Ltd. or a three-component adhesive (" AN "
-187, P-6-1, 814-1 "Sixon Co., Ltd.
Manufactured in the same manner, and the adhesive strength was measured in the same manner. The results are shown in Table 3.

[0025]

[Table 3] From Table 3, it can be seen that all of the rubber-based composite materials of the present example were fiber breakage, and the fluororesin fiber layer and the rubber substrate were well bonded. The adhesive strength of the fluororesin fiber layer in the rubber-based composite material depends on the strength of the fluororesin fiber body itself, and shows good adhesive strength without using an adhesive. It is also clear that can be increased.

Since the adhesiveness and the weldability between the fluororesin fiber body and the fluororesin film or the fluororesin sheet are good, a fluororesin film or the like is formed on the surface of the fluororesin fiber layer of the rubber-based composite material of the above-mentioned embodiment. It is also preferable to adhere or weld. In this way, the rubber does not appear on the surface, so that the sliding resistance, the fixing force, and the like can be further reduced. Further, since the pores of the fluororesin fiber layer are filled with the adhesive or the molten resin, it is expected that the adhesive strength by the above measuring method will be further improved.

[0027]

That is, according to the rubber-based composite material of the present invention, since the surface has the characteristics of fluororesin while having rubber elasticity, the rubber material has excellent sliding characteristics and chemical resistance of fluororesin. And heat resistance can be imparted. According to the method for producing a rubber-based composite material of the present invention, since it is only necessary to place the fluororesin fiber body in the mold and perform compression molding, a rubber-based composite material having the above-mentioned excellent properties is significantly increased in the number of steps. It is stable and easy to manufacture.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a rubber-based composite material of the present invention.

FIG. 2 is a micrograph showing a particle structure of a rubber-based composite material according to an example of the present invention.

FIG. 3 is a micrograph showing a particle structure of a rubber-based composite material according to an example of the present invention.

FIG. 4 is an explanatory diagram showing a method of measuring sliding resistance in an example of the present invention.

FIG. 5 is a diagram showing a sliding pattern between a rubber-based composite material and an EPDM plate according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a fixing method used when measuring the fixing force in the example of the present invention.

FIG. 7 is an explanatory diagram showing a method for measuring adhesive strength in an example of the present invention.

[Explanation of symbols]

1: Rubber-based composite material 10: Rubber base material 1
1: Fluororesin fiber layer

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[Procedure amendment]

[Submission date] February 28, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

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[Procedure Amendment 2]

[Document name to be corrected] Drawing

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[Correction method] Change

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[Figure 3]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location // B29K 21:00 105: 06 105: 24 227: 12 B29L 31:26 (72) Inventor Fukuda Masahito 1 Ochiai, Ochiai, Nagasaki, Kasuga-cho, Nishi Kasugai-gun, Aichi Prefecture, Toyoda Gosei Co., Ltd.

Claims (4)

[Claims] 1. A rubber comprising a rubber base and a fluororesin fiber layer formed on the surface of the rubber base and integrally bonded to the rubber base by being impregnated with the rubber of the rubber base. Base composite material. 2. A fiber made of a fluororesin is placed on the surface of a base material made of unvulcanized rubber, heated and pressurized to impregnate the unvulcanized rubber between the fibers and vulcanize the base material. A method for producing a rubber-based composite material, which comprises integrally bonding fibers to the base material. 3. The method for producing a rubber-based composite material according to claim 2, wherein the fiber made of fluororesin constitutes a papermaking body. 4. A rubber base, a fluororesin fiber layer formed on the surface of the rubber base and integrally bonded to the rubber base by being impregnated with the rubber of the rubber base, and an integral body on the surface of the fluororesin fiber layer. A rubber-based composite material, comprising: