JPH0367637A - Adhesive method of fluorine resin and rubber - Google Patents

Abstract

PURPOSE:To stick firmly a fluorine resin and a rubber to each other without making use of an organic adhesive agent, by method wherein a specific rubber composition is stuck directly to the surface of a fluorine resin treated with a metallic sodium solution and then the rubber composition is vulcanized by heating the same. CONSTITUTION:A rubber composition which contains a 10-200 pts.wt. filling agent whose absorption of dibutylamine is 10-300 milliequivallent/kg on the basis of 100 pts.wt. rubber and a value of (absorption of dibutylamine)X(pts.wt. of filling agent on the basis of 100 pts.wt. rubber) is 1X10<3>-10<3> is stuck directly to the surface of fluorine resin treated with a sodium solution. Then the rubber composition is vulcanized by heating the same and the vulcanized rubber and the fluorine resin are stuck together.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for bonding a fluororesin and rubber, and more particularly, to a method for bonding a fluororesin and rubber, and more particularly, to a method for bonding a fluororesin and rubber, and more particularly, to a method for bonding a fluororesin and rubber, and more particularly, to a method for bonding a fluororesin and rubber, and more particularly, to a method for bonding a fluororesin and rubber, and more particularly, to a method for bonding a fluororesin and rubber. Regarding the method of adhesion between rubber and rubber.

Technical Background of the Invention Fluororesins such as polytetrafluoroethylene (hereinafter sometimes referred to as PTFE) have excellent heat resistance, weather resistance, chemical resistance, mold releasability, sliding properties, and mechanical strength. It also has excellent electrical properties such as low dielectric constant and dielectric loss tangent, so it can be used not only for seal parts such as packing and gaskets, and mechanical parts such as bearings and sliding materials, but also for electronic equipment parts such as printed circuit boards. It is widely used as a lining material for piping parts and tanks that require corrosion resistance.

However, when a fluororesin such as PTF-E is formed into a molded article, its surface free energy is extremely low, so it is quite difficult to bond it to other materials such as rubber, even if an adhesive is used. For this reason, methods have been proposed for increasing the adhesiveness between fluororesins such as PTFE and rubber. One method is to chemically activate the fluororesin surface by treating it with a solution of metallic sodium dissolved in liquid ammonia, and then apply a rubber composition to this surface via an organic adhesive such as an epoxy resin. There is a method of adhering the fluororesin and the rubber, then heating to vulcanize the rubber composition and adhering the fluororesin and the rubber.

However, this method uses an organic adhesive to bond the fluororesin and rubber, so it is difficult to apply the adhesive and
A drying process is required, and the adhesive strength between the fluororesin and rubber tends to change depending on the method of applying the adhesive, the drying process, or the storage process after applying the adhesive.

Furthermore, when the fluororesin and rubber are both thin, when the fluororesin and rubber are integrated using an organic adhesive, the resulting laminate may warp.

Purpose of the Invention The present invention attempts to solve the problems associated with the prior art as described above, and is a method of firmly adhering a fluororesin such as PTFH and rubber without using an organic adhesive. The purpose is to provide a method for

Summary of the Invention The method of adhering a fluororesin and rubber according to the present invention is to apply a filler having a diptylamine adsorption amount of 10 to 300 meq/kg per 100 parts by weight of rubber onto the surface of a fluororesin treated with a sodium metal solution. Contains 10 to 150 parts by weight, and the value of (adsorption amount of dibutylamine) x (parts by weight of filler per 100 parts by weight of rubber) is 2 x 103 to 10 x
It is characterized in that the vulcanized rubber and the fluororesin are bonded by directly applying the rubber composition No. 103 and then heating to vulcanize the rubber composition.

According to the present invention, a fluororesin and rubber can be directly and firmly bonded together without using an organic adhesive.

DETAILED DESCRIPTION OF THE INVENTION The method of adhering a fluororesin and rubber according to the present invention will be specifically described below.

Examples of the fluororesin to be bonded to rubber in the present invention include polytetrafluoroethylene (PTPE), PFA which is a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, and copolymer of tetrafluoroethylene and hexafluoropropylene. FEP is a polymer, and EP is a copolymer of tetrafluoroethylene, hexafluoropropylene, and perfluoroalkyl vinyl ether.
In addition to H, other fluororesins can be used. Among these, PTFE is particularly preferred in consideration of the heat resistance, chemical resistance, mechanical strength, etc. of the fluororesin.

Such a fluororesin may be a fluororesin itself, or may contain a filler.

Furthermore, the shape of such a fluororesin may be a sheet shape or a cross shape.

The surface of the fluororesin that adheres to the rubber is treated with a metallic sodium solution. As a metal sodium solution,
Metallic sodium solutions that have been conventionally used to treat fluororesin surfaces can be used, but specifically, metal sodium solutions dissolved in liquid ammonia, metal sodium solutions dissolved in naphthalene in tetrahydrofuran, etc. is used.

When a fluororesin is treated with a metallic sodium solution in this manner, fluorine is removed from the fluororesin surface in the form of sodium fluoride, and the surface is chemically activated to form a surface active layer. The depth of this surface active layer is about 0.
It is desirable that the thickness is about 0.01 m+s or less, preferably about 0.001 mm or less.

In addition to the above-mentioned method of treating the surface of a fluororesin with a metal sodium solution, there are also known methods for treating the surface of a fluororesin, such as sputter etching the fluororesin surface and plasma etching the fluororesin surface. Even if the rubber composition according to the present invention is used on the surface of a fluororesin treated by a method other than the treatment with a metal sodium solution, the fluororesin and rubber cannot be firmly bonded.

In the present invention, the rubber composition to be adhesively integrated with the fluororesin as described above contains at least a rubber material and a filler.

The rubber material plays a role in binding the above fibers, and includes nitrile rubber (NBR), styrene-butadiene rubber (
SBR), isoprene rubber (IR), chloroprene rubber (CR), butadiene rubber (BR), butyl rubber (I
IR), ethylene-propylene rubber (EPM), fluororubber CPPM), silicone rubber (Si), chlorosulfonated polyethylene (C8M), ethylene vinyl acetate rubber (EVA), chlorinated polyethylene (CPE), chlorinated butyl rubber (CIR), epichlorohydrin rubber (ECO),
Nitrile isoprene rubber (NIR), natural rubber (NR)
Known rubbers such as rubber are widely used.

The filler contained in such a rubber composition has a dibutylamine adsorption amount of 10 to 300 meq/kg, preferably 30 to 260 meq/kg, and more preferably 3
5 to 260 milliequivalents/kg.

Such fillers are present in amounts of 10 to 2 per 100 parts by weight of rubber.
00 parts by weight, preferably 30 to 150 parts by weight, more preferably 40 to 150 parts by weight.

The rubber composition according to the present invention contains the filler as described above (
The value of (adsorption amount of dibutylamine) x (parts by weight of filler per 100 parts by weight of rubber) is 1 x 103 to 10 x 103, preferably 2.5 x 103 to 10 x 103, more preferably 4 x 103 to 10 x 103. It is desirable to contain it in such an amount.

Specifically, the fillers mentioned above include kaolin,
Calcined Ray Hyrophyllite, bentonite, sericite, zeolite, nephelinsinite, talc, attapulgite, wollastonite, synthetic aluminum silicate, synthetic calcium silicate, diatomite, silica powder, hydrated silicic acid, anhydrous silicic acid Fillers containing hydroxyl groups such as aluminum hydroxide, calcium sulfate, and calcium carbonate are used. Among these, especially hydrated silicic acid (wet method silicic acid)
, aluminum silicate, etc. are preferred.

This filler has an average particle size of 5 μm or less, preferably 2 to 0
．． 01 μm and a specific surface area of 20 i/g or more, preferably 40 to 500 i/g.

Table 1 shows the relationship between the main fillers containing hydroxyl groups used in the present invention and their adsorption amounts of butylamine.

Table 1 In addition to the rubber material and filler described above, the rubber composition used in the present invention may also contain a rubber chemical.

Rubber chemicals include (i) vulcanizing agents such as sulfur, zinc oxide, magnesium oxide, peroxide, and dinitrosobenzene;
(ii) Thiazole compound, polyamine compound,
Sulfenamide compounds, dithiocarbamate compounds, aldehyde amine compounds, guanidine compounds,
Vulcanization accelerators such as thiourea compounds and xanthate compounds are used.

Further, the rubber composition used in the present invention may contain fillers other than those described above, such as carbon, basic magnesium carbonate, aluminum hydroxide, magnesium hydroxide, etc. is used.

The rubber composition can also contain a process oil, such as a naphthenic process oil or a paraffinic process oil, or a dispersant.

The rubber composition as described above is directly attached to the fluororesin surface treated with a metal sodium solution without using an organic adhesive, and then heated to vulcanize the rubber composition and bond the vulcanized rubber and fluorine resin. Glue with resin.

The rubber composition is heated to 150 to 200°C, preferably 16°C.
It is desirable to carry out the heating at a temperature of 0 to 180°C, and it is preferable to pressurize at the same time as the above-mentioned heating.

This pressurization is preferably about 10 to 100 kg/c/.

In this way, a rubber composition containing a specific filler is directly adhered to the surface of a fluororesin treated with a sodium metal solution, and then heated to vulcanize the rubber composition and combine the vulcanized rubber with fluorine. It is thought that when the rubber and the fluororesin are bonded together, the hydroxyl groups contained in a specific amount in the filler and the molecules of the fluororesin surface active layer bond through hydrogen bonds or the like, thereby firmly adhering the rubber and the fluororesin.

When a fluororesin and rubber are bonded together as described above, the adhesive strength improves approximately in proportion to the amount of hydroxyl groups in the filler contained in the rubber composition. The adhesive strength between the fluororesin and the rubber is preferably 700 g/c+n or more, and more preferably 1000 to 3300 g10.

By the way, if the amount of hydroxyl groups in the filler contained in the rubber composition increases, the adhesive force between the fluororesin and the rubber will improve, but if too much filler is blended into the rubber composition, the Mooney viscosity of the rubber composition will increase. increases too much, making it difficult for the rubber composition to mix with the rolls, reducing processability, and
The physical properties of the rubber deteriorate. Therefore, in the present invention, the rubber composition contains 10 to 200 parts by weight of a filler having a diptylamine adsorption amount of 10 to 300 mm/kg/kg per 100 parts by weight of rubber, and (dibutylamine adsorption amount) x ( The filler is blended in an amount such that the value (parts by weight of filler per 100 parts by weight of rubber) is from 1×10 to 10×10 3 .

Effects of the Invention According to the present invention, the fluororesin surface treated with a metal sodium solution contains 10 to 200 parts by weight of a filler having a diptylamine adsorption amount of 10 to 300 meq/Mg per 100 parts by weight of rubber, and A rubber composition with a value of (adsorption amount of diptylamine) x (parts by weight of filler per 100 parts by weight of rubber) of 1 x 103 to 10 x 103 is directly attached, and then heated to vulcanize the rubber composition. In addition, since the vulcanized rubber and the fluororesin are bonded together, the fluororesin and the rubber can be directly and firmly bonded together without using an organic adhesive such as an epoxy resin.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 A rubber composition having the following composition was prepared.

Butyl rubber 100 parts by weight (Butyl 365 manufactured by Japan Synthetic Rubber Co., Ltd.) Dispersant 1 part by weight Vulcanizing agent
2 parts by weight (4,4-dithiodimorpholine) Vulcanization accelerator 2 parts by weight (tetramethylthiuram disulfide) Zinc oxide
3 parts by weight carbon
10 parts by weight Wet process silicic acid 4
0 parts by weight of Pushiru VN-3) (diptylamin adsorption amount 230-260 milliequivalents/k
g) On the other hand, stick-shaped polytetrafluoroethylene (PTF)
The surface of E) is treated with an ammonia solution of metallic sodium,
Processed for 15-30 seconds at room temperature.

A sheet made of the rubber composition as described above was adhered directly to the PTFE surface treated with the ammonia solution of metallic sodium without using an adhesive, and then heated to 170°C and 70kg/ The fluororesin and rubber were bonded and integrated by applying pressure using cj.

The adhesive strength between the fluororesin and rubber in the thus obtained integrated product was evaluated as follows.

The obtained integrated product was cut into a strip of length (7) and width 1c+n to prepare a sample. The thickness of the PTFE layer in this integrated product was 0.8 m+s, and the thickness of the rubber layer was 1.2 m+s.

Using this integrated product, PTF was tested using a universal tensile tester.
The adhesive strength (g/am) between the E layer and the rubber layer was measured at room temperature and a tensile speed of 50 mm/min.

The adhesive strength between fluororesin and rubber is 3300 kg fl
It was o.

The relationship between such adhesive strength and (adsorption amount of dibutylamine) x (parts by weight of filler per 100 parts by weight of rubber) in the rubber composition is shown in FIG.

Example 2 In Example 1, Pushiru VN-3) was added to the wet method silicic acid.
The procedure was the same as in Example 1, except that 50 parts by weight of hot process silicic acid (ZILTON R2, dibutylamine adsorption amount 230-260) was used instead.

The adhesive strength between fluororesin and rubber is 2350 kg f/
There was a cm.

In addition, this adhesive strength and (adsorption amount of dibutylamine) in the rubber composition x (parts by weight of filler per 100 parts by weight of rubber)
Figure 1 shows the relationship between

Example 3 In Example 1, Pushiru VN-3) was added to the wet method silicic acid.
The procedure was the same as in Example 1, except that 50 parts by weight of hard clay (crown clay dibutylamine adsorption ff 140-60) was used instead.

The adhesive strength between fluororesin and rubber is 700 kg f7
It was 0m.

Also, this adhesive strength and (adsorption amount of dibutylamine) in the rubber composition x (parts by weight of filler per 1 part by weight of 100 rubber)
Figure 1 shows the relationship between

Example 4 In Example 1, Bucil VN-3) was added to the hot process silicic acid.
The procedure was the same as in Example 1, except that 00 parts by weight of hard clay (crown clay, dibutylamine adsorption amount: 40 to 60) was used instead.

The adhesive force between fluororesin and rubber is 2250 kg f/
It was cm.

In addition, this adhesive strength and (adsorption amount of dibutylamine) in the rubber composition x (parts by weight of filler per 100 parts by weight of rubber)
Figure 1 shows the relationship between

Example 5 In Example 1, Pushiru VN-3) was added to the mixed process silicic acid.
The same procedure as in Example 1 was carried out except that 50 parts by weight of calcium silicate (Silmos T1 dibutylamine adsorption amount 60 to 100) was used instead of .

The adhesive strength between fluororesin and rubber is 1500 kg f/
It was am.

In addition, this adhesive strength and (adsorption amount of dibutylamine) in the rubber composition x (parts by weight of filler per 100 parts by weight of rubber)
Figure 1 shows the relationship between

Example 6 In Example 1, Pushiru VN-3) was added to the hot process silicic acid.
The procedure was the same as in Example 1, except that 50 parts by weight of hard clay (clay RC32, dibutylamine adsorption: 40-60) was used instead.

The adhesive strength between fluororesin and rubber is 840 kgf/
It was a mark.

In addition, this adhesive strength and (adsorption amount of dibutylamine) in the rubber composition x (parts by weight of filler per 100 parts by weight of rubber)
Figure 1 shows the relationship between

Comparative Example 1 The same procedure as in Example 1 was carried out except that 100 parts by weight of calcium carbonate (Sunlite 300, dibutylamine adsorption amount 10) was used instead of Pushiru VN3) for the wet process silicic acid.

The adhesive strength between fluororesin and rubber is 430 kgf/
There was a cm.

Furthermore, the relationship between this adhesive strength and (dibutylamine adsorption x (parts by weight of filler per 100 parts by weight of rubber) in the rubber composition) is shown in FIG.

Comparative Example 2 In Example 1, Pushiru VN-3) was added to the mixed method silicic acid.
The same procedure as in Example 1 was carried out, except that 50 parts by weight of calcium carbonate (Sunlight 300, dibutylamine adsorption ffi 10) was used instead of .

The adhesive strength between fluororesin and rubber is 360 kgf/
It was cm.

Further, the relationship between this adhesive force and (dibutylamine adsorption i!L>X (parts by weight of filler per 100 parts by weight of rubber) in the rubber composition is shown in FIG. 1.

[Brief explanation of drawings]

Figure 1 shows (adsorption amount of dibutylamine) x
FIG. 3 is a diagram showing the relationship between (parts by weight of filler per 100 parts by weight of rubber) and adhesive strength.

Claims (1)

[Claims] The fluororesin surface treated with a metallic sodium solution contains 10 to 200 parts by weight of a filler with a dibutylamine adsorption amount of 10 to 300 meq/kg per 100 parts by weight of rubber, and (dibutylamine adsorption amount) x ( Parts by weight of filler per 100 parts by weight of rubber) is 1 x 10^3 ~ 1
Adhesion of a fluororesin and rubber, characterized by directly attaching a rubber composition of 0x10^3 and then heating to vulcanize the rubber composition to adhere the vulcanized rubber and the fluororesin. Method.