JPH0249221B2 - HINENCHAKUDANSEIBARUBU - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-adhesive elastic valve, and more particularly to a non-adhesive elastic valve that prevents the valve from sticking to the valve seat during opening and closing.
Furthermore, the present invention relates to a non-stick elastic valve that preferably exhibits sealing properties due to its elasticity and can be widely applied to purposes requiring heat resistance, fuel oil resistance, ozone resistance, NOx resistance, etc.

For example, in engine reed valves,
Fuel on the intake side and exhaust gas on the exhaust side are controlled by reed valves, but if the valves are left inactive for a long period of time, the valves and valve seats may become stuck and cannot perform their intended functions properly. It disappears. Therefore, there is a need for a valve seat that is free from such problems and has excellent non-stick properties.

In order to meet such requirements, a reed valve has been proposed in which a fluororesin layer is provided between the reed valve and the valve seat (Japanese Utility Model Publication No. 45223/1983). Of these reed valves, when a fluororesin layer is provided on the reed valve side, when crimped in a high temperature and high humidity environment,
During operation, it can cause trouble due to sticking to the rubber layer of the valve seat, and it is still not perfect. On the other hand, when a fluororesin layer is provided on the rubber valve seat side, there may be problems with poor adhesion between the rubber layer and the fluororesin layer, or between the two layers during use due to the difference in elastic modulus between the rubber and the fluororesin. Due to distortion, the rubber layer and fluororesin layer tend to peel off.

As a result of repeated studies to eliminate the drawbacks of the conventional valves mentioned above, the inventors of the present invention have found that satisfactory elasticity can be maintained by providing a coating film obtained from a specific fluoro rubber paint on the pressure contact surface of the valve. The present inventors have discovered that it is possible to obtain a non-adhesive elastic valve having sufficient sealing properties and anti-sticking properties on its surface, and have completed the present invention.

That is, the gist of the present invention is a non-adhesive elastic valve having a coating film formed by applying and curing a fluororubber paint containing fluororubber, fluororesin, aminosilane and a liquid carrier on the pressure contact surface. hand,
The weight ratio of the fluororubber and the fluororesin is 95:5 to 95:5.
A non-adhesive elastic valve characterized by a ratio of 35:65.

In the valve of the present invention, the coating film is preferably provided on the valve seat directly or via a rubber layer, and is provided only on the reed valve side. Furthermore, it is also preferable that the valve seat is provided with the coating film of the present invention, and the reed valve side is provided with a fluororesin layer of the prior art.

In addition to the above characteristics, the non-adhesive elastic valve of the present invention has the following features:
For example, when used in a reed valve installed on the intake side of an engine, it has excellent gasoline resistance and gasohol resistance, and functions normally without sticking. Heat resistant and resistant even when used in reed valves.
It has excellent NOx and ozone resistance, and also functions normally without sticking. Furthermore, the fluororubber paint used in the present invention has excellent adhesion to the valve body and does not easily peel off from the valve body.

In the present invention, the fluororubber coating film obtained by blending a specific amount of fluororesin can impart excellent non-adhesive properties to the surface without substantially impairing the adhesion to the substrate and mechanical properties. Because the fluororesin, which itself is non-adhesive, unexpectedly gathers on the surface of the fluororubber coating, the fluororesin can be used without adversely affecting the adhesion to the substrate and the mechanical properties of the coating. It is believed that the above performance is effectively exhibited on the surface of the fluororubber coating film.

According to our research, when we measure the fluorine content on the surface of a 50 μm thick coating film cured at 300°C for 30 minutes and on the adhesive surface with the substrate using fluorescent X-ray analysis, we find that the former It has been confirmed that the ratio of the former to the latter tends to increase as the curing temperature increases.

The fluororubber used in the present invention is a highly fluorinated elastic copolymer, and a particularly preferred fluororubber is usually 40 to 85 mol% of vinylidene fluoride and copolymerized therewith. Elastic copolymers with at least one other fluorine-containing ethylenically unsaturated monomer may be mentioned. Fluororubber containing iodine in the polymer chain has, for example, 0.001 to 10% by weight, preferably 0.01 to 5% by weight of iodine bonded to the end of the polymer chain, and the same 40 to 85 mol% of vinylidene as mentioned above. Fluororubber whose main composition is an elastic copolymer consisting of a fluoride and at least one other fluorine-containing ethylenically unsaturated monomer that can be copolymerized with the fluoride (see JP-A-52-40543) ). Other fluorine-containing ethylenically unsaturated monomers that can be copolymerized with vinylidene fluoride to give elastic copolymers include hexafluoropropylene, pentafluoropropylene, trifluoroethylene, trifluorochloroethylene, and tetrafluoroethylene. Typical examples include ethylene, vinyl fluoride, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), and perfluoro(propyl vinyl ether). Particularly desirable fluororubbers are vinylidene fluoride/hexafluoropropylene dielastic copolymers and vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene terelastic copolymers. In addition, the fluororesin used in the present invention includes polytetrafluoroethylene, tetrafluoroethylene, and at least one other ethylenically unsaturated monomer copolymerizable therewith (for example, olefins such as ethylene and propylene, Copolymers with halogenated olefins such as hexafluoropropylene, vinylidene fluoride, chlorotrifluoroethylene, vinyl fluoride, perfluoroalkyl vinyl ethers, etc.), polychlorotrifluoroethylene, polyvinylidene fluoride, etc. . Among these, preferred fluororesin is at least one of polytetrafluoroethylene, tetrafluoroethylene and hexafluoropropylene, perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, and perfluoropropyl vinyl ether (usually 40 mol% based on tetrafluoroethylene). (included below). Furthermore, the aminosilane compound used in the present invention not only functions as a vulcanizing agent for fluorocarbon rubber, but also greatly contributes to improving the adhesion to the base material, and can be safely used in liquid media. . An example of a typical compound is γ-aminopropyltriethoxysilane (hereinafter referred to as A-1100
), N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-(trimethoxysilylpropyl)ethylenediamine, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, γ-ureidopropyltriethoxysilane , β-aminoethyl-β-aminoethyl-γ
-Aminopropyltrimethoxysilane, etc.

Furthermore, the liquid carrier used in the present invention is selected from organic solvents such as lower ketones, lower esters, and cyclic ethers, water, and mixtures of water and water-soluble organic liquids. Examples of water-soluble organic liquids include alcohols. can. Among these liquid carriers, water is most preferred from the viewpoint of coating workability and not damaging the rubber layer of the base material.

Furthermore, inorganic fibrous substances as other substances contained in the fluoro rubber coating of the present invention are used to improve the compression recovery properties of the fluoro rubber coating, and typical examples include glass fiber, carbon fiber, etc. , asbestos fiber, potassium titanate fiber, etc. This inorganic fibrous material has an average length of at least
It is desirable that the thickness is 1μ, preferably 1 to 100μ.

In addition, the amine compound (hereinafter referred to as "amine compound") that is optionally added to the fluororubber paint of the present invention mainly functions as a vulcanizing agent for the fluororubber, and also works as a vulcanizing agent for the fluororubber together with the aminosilane compound. Typical compounds include monoamines such as ethylamine, propylamine, butylamine, benzylamine, allylamine, n-amylamine, ethanolamine, ethylenediamine, trimethylenediamine, tetramethylenediamine, Diamines such as hexamethylene diamine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5,5]undecane (hereinafter referred to as V-11), diethylenetriamine, triethylenetetramine , tetraethylenepentamine, pentaethylenehexamine, and the like, among which amine compounds having two or more terminal amino groups are preferred.

To prepare the fluororubber paint of the present invention, usually
A pigment, an acid acceptor, a filler, etc. are blended into a mixture of fluororubber and fluororesin and a liquid carrier according to a conventional method (a surfactant may be further used if necessary). By adding the aminosilane compound and, if necessary, an amine compound to the dispersion liquid (additives such as the pigment, acid acceptor, filler, etc. may be added as necessary) and thoroughly mixing by a conventional method, Make a uniform fluoro rubber paint.

The ratio of fluoro rubber and fluoro resin is 95:5 by weight.
~35:65, and when the ratio of fluororesin is less than the above lower limit, the desired non-adhesiveness and lubricity will not be improved sufficiently, and conversely, when it is more than the above upper limit, the desired thickness of the coating film will not be achieved. , and cracks and pinholes are likely to occur in the coating film.

The amount of the aminosilane compound added is usually 1 to 30 parts by weight, preferably 1 part by weight per 100 parts by weight of fluororubber.
~20 parts by weight. When an amine compound is added as desired, it is blended so that the total sum of the aminosilane compound and the amine compound takes the above value. In this case, the molar ratio of the aminosilane compound to the amine compound is selected from a range of 1:99 to 90:10.

As the acid acceptor, those commonly used in the vulcanization of fluororubber can be similarly used, such as one or more divalent metal oxides or hydroxides. Specific examples include oxides or hydroxides of magnesium, calcium, zinc, lead, and the like. Further, as the filler, silica, clay, diatomaceous earth, talc, carbon, etc. are used.

The fluororubber paint according to the present invention is applied or impregnated onto a base material by a normal coating method (brushing, dipping, spraying, etc.) under a temperature condition of room temperature to 400°C, preferably 100 to 400°C. The desired fluororubber coating film can be obtained by curing for an appropriate period of time.

The film thickness of the fluororubber paint according to the present invention is preferably between 10 and 300μ when applied directly to the valve body, and between 10 and 100μ when applied through a rubber layer; If the film thickness is less than 300 microns, the elasticity will be insufficient and there is a risk that the entire surface of the valve body will be uneven and some parts will not be covered. The most preferable film thickness is 10 to 50 microns because there is a risk of cracks in the film or difficulty in forming a uniform film. The fluororubber coating film of the present invention thus obtained has the properties inherent to fluororubber, has excellent adhesion to the valve body, and has excellent mechanical properties. Gives stickiness.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

1, 2, and 3 show cross-sectional views of different aspects of an engine reed valve that is an embodiment of the present invention. In these reed valves, paint or exhaust gas passing through the valve hole 4 is controlled by the operation of the reed valve 2. The valve body 1 and the reed valve 2 are made of metal and are fixed at one end with a pin 6.

The non-adhesive elastic valve seat according to the present invention is attached to the valve body 1 directly or through a rubber valve seat 5, as shown in FIGS. 1 and 2, respectively. Non-adhesive fluororubber coating film coated and cured with the fluororubber paint according to the present invention obtained by blending Liquid and B in a ratio of 5 parts of B to 100 parts (by weight) of A. 3.

A-liquid Fluororubber Note ¹⁾ Aqueous dispersion (fluororubber content 60% by weight, including nonionic HS-208)...166 parts Fluororesin Note ²⁾ Aqueous dispersion (FER content as fluororesin) 50% by weight, nonionic HS
-208)...150 parts Magnesium oxide...3 parts Medium thermal carbon...20 parts Nonionic HS-210 (manufactured by NOF Corporation)...2 parts Water...50 parts Note 1) Vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene Elastic copolymer (hereinafter simply referred to as fluororubber).

Note 2) Tetrafluoroethylene/hexafluoropropylene copolymer (hereinafter referred to as FEP).

B-liquid A-1100...40 parts V-11...20 parts Water...40 parts After uniformly mixing A-liquid and B-liquid, the pressure welding was carried out using a fluoro rubber paint obtained by separate purification using a 200-mesh wire mesh. It was applied to the surface by spray painting (nozzle diameter 1.0 mm: spray pressure 2.0 Kg/cm ² ). the result,
There were no abnormalities in the spray coating, and a smooth coating film with a thickness of approximately 30 μm was obtained by curing at 300°C for 15 minutes.

The following pressure contact test was conducted to examine the non-stick properties of each of the obtained bulbs.

In other words, with each valve in the closed state, the temperature is 60℃,
It was left for one week under a load of 500 g in an atmosphere with relative humidity of 90%. Thereafter, when the load was removed, the reed valve opened easily.

For comparison, a pressure contact test was conducted under the same conditions as above for a reed valve similar to that shown in FIG. 2, except that the fluororubber coating film of the present invention was not provided. As a result, unlike the case of the above embodiment, the reed valve did not open easily. This indicates that the reed valve does not operate smoothly and may cause trouble.

[Brief explanation of drawings]

Figure 1 is a sectional view of an engine reed valve in which the fluoro rubber coating of the present invention is directly applied to the surface of the valve seat of the valve body, and Figure 2 is a cross-sectional view of a reed valve for an engine in which the fluorocarbon rubber coating of the present invention is applied directly to the surface of the valve seat of the valve body. FIG. 3 is a sectional view of an engine reed valve provided with the fluororubber coating film of the invention. FIG. be. 1... Valve body, 2... Reed valve, 3... Paint film, 4... Valve hole, 5... Rubber valve seat, 6... Pin.

Claims (1)

[Scope of Claims] 1. A non-adhesive elastic valve having a coating film formed by applying and curing a fluororubber paint containing fluororubber, fluororesin, aminosilane and a liquid carrier on the pressure contact surface, , a non-adhesive elastic valve characterized in that the weight ratio of the fluororubber to the fluororesin is 95:5 to 35:65. 2. The valve according to claim 1, wherein the valve is a valve of an intake and exhaust system of an engine. 3. The valve according to claim 1, wherein the fluororubber paint contains an aminosilane compound in a proportion of 1 to 30 parts by weight based on 100 parts by weight of fluororubber. 4. The valve according to any one of claims 1 to 3, wherein the fluororubber paint further contains an amine compound. 5. The valve according to claim 3, wherein the fluororubber paint contains an amine compound having at least two terminal amino groups. 6. The valve according to claim 4 or 5, wherein the molar ratio of the aminosilane compound to the amine compound is 1:99 to 90:10. 7. The valve according to claim 1, wherein the fluororubber paint contains an inorganic fibrous substance. 8. The valve according to claim 1, wherein the inorganic fibrous material contained in the fluororubber paint is selected from the group consisting of glass fiber, carbon fiber, asbestos fiber, and potassium titanate fiber. 9. The valve according to claim 1, wherein the liquid carrier contained in the fluororubber paint is water.