JPH04165163A - Diapharagm valve - Google Patents

Abstract

PURPOSE:To obtain a diaphragm valve of a long life by heating a rubber compound, formed by mixing a peroxide into a composition composed of the specific rate of fluoro-rubber and EPDM or EPM rubber, in a die to mold a diaphragm. CONSTITUTION:A rubber compound, formed by mixing a peroxide into a composition containing 25-95wt.% of fluoro-rubber and 5-75wt.% of EPDM or EPM rubber as the rubber part, is heated in a die to mold a diaphragm 1 integrally by the vulcanizing reaction caused by the peroxide. The corrosion resistance of the thus obtained diaphragm 1 is not much changed from the case of using only fluoro-rubber, and the corrosion resistance is increased slightly as the content of fluoro-rubber is increased, whereas sealing performance is increased as the content of EPDM or EPM is increased. The diaphragm 1 is thus provided with the corrosion resistance of fluoro-rubber and the sealing characteristic of EPDM or EPM so as to have the advantage of a long life, and distortion is not generated during use since the peroxide can be decomposed completely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a diaphragm valve with excellent corrosion resistance.

[Prior art 1] Conventionally, the material of the diaphragm part of the diaphragm valve is a cloth-lined rubber band consisting of two layers as shown in FIG. A tire flam valve was used in which the chloroprene rubber layers 3 and the interface 4 between them were bonded with an adhesive material layer, for example an adhesive or a tie rubber layer (adhesive rubber layer).

However, the diaphragm made of this laminated rubber sheet has poor sealing properties and the valve is strongly tightened, which tends to cause the tire flam to separate. Therefore, it had the disadvantage of short lifespan.

[Problems to be Solved by the Invention] An object of the present invention is to provide a tire 7 ram valve with a long life.

[Measures to solve the problem 1: The durability of the diaphragm part of the tire flamm valve depends on the corrosion resistance of IA quality, or the life of the diaphragm can be extended if the whole part is replaced with fluororubber, which has high chemical resistance. This poses an economical problem because the sealing properties are poor and fluororubber is expensive.

In order to eliminate the drawbacks of conventional laminated rubber, the present inventors attempted to mix fluororubber with other rubbers to simultaneously achieve economic efficiency and prevention of delamination, and developed a diaphragm rubber for tire flamm valves. As a result of examining various rubbers to be blended with fluororubber, we found that a diaphragm manufactured by integrally molding a composition consisting of fluororubber blended with peroxide and EPDM rubber or EPM rubber is the most suitable fluid. Regarding corrosion resistance, the present inventors have discovered that the material exhibits almost the same durability as a fluororubber surface, and has the advantage that there is no delamination because it is integrally molded, leading to the creation of the present invention.

In addition, we discovered that even if the rubber band consists of two layers, co-vulcanization molding of the two layers as one unit does not cause layer peeling.Using this knowledge, we developed a two-layer rubber consisting of an EPDM layer and a fluororubber layer. The present invention has been completed for use as a material for diaphragms.

That is, the present invention consists of a diaphragm according to the following first and second aspects.

■ Fluororubber 25-95% by weight and EPDM or E
A composition consisting of 75 to 5% by weight of PM rubber is mixed with a peroxide, and a rubber compound is heated in a mold to form a rubber compound by a vulcanization reaction caused by the peroxide. A diaphragm valve characterized by having a diaphragm molded into.

In a tire plum consisting of 22 layers, on the flow path side layer)/
The rubber component is a composition consisting of 50 to 100% by weight of raw rubber and 50 to 0% by weight of EPDM or EPM rubber, a rubber layer containing peroxide is arranged, and 0 to 50% by weight of fluororubber is provided as the valve drive part side layer. % and E PDM or EPM rubber 1
A composition consisting of 00 to 50% by weight is used as the rubber component, a rubber layer containing peroxide is arranged, and both rubber layers are heated simultaneously in a mold to form two layers through a co-vulcanization reaction with the peroxide. A diaphragm valve characterized by having a diaphragm integrally bonded and vulcanized.

The diaphragm used in the tire phragm valve of the present invention is usually disk-shaped, and the tip 26 of the valve is embedded in the medium heat as shown in FIG.

The present invention will be explained in more detail with reference to drawings of embodiments. In the following explanation, for the sake of simplicity, a case is described in which EPDM is used. However, the present invention is not limited to EPDM, and EPM can also be used in the same way instead of EPDM or mixed with it. can.

The diaphragm of the first aspect of the present invention is shown in the above item 1, and the circular frame-shaped diaphragm l shown in FIG. It is integrally molded using peroxide.

When the total rubber content of EPDM rubber and fluororubber in the entire compounded composition is 100% by weight, the blending ratio of fluororubber in the diaphragm of the first embodiment of the present invention is 25 to 95% by weight,
The amount is preferably 35 to 90% by weight, and the remainder may be EPDM. The greater the blending ratio of the 7-no-rubber, the greater the corrosion resistance, and the greater the content of EPDM, the better the sole properties. The diaphragm valve of the present invention is
An appropriate blending ratio can be selected depending on the conditions of use.

EPDM mixed with fluororubber is characterized by having properties that combine the corrosion resistance of fluororubber and the sealing properties of EPDM.

The diaphragm of the first aspect of the present invention is vulcanized and molded using peroxide that has been mixed in advance. That is, the first stage vulcanization reaction is performed by heating at 140 to 190°C for 3 to 30 minutes under pressure with a mold, and then taken out from the mold and heated at 140 to 190°C for 1 to 8 hours. second
It is characterized by the fact that it is molded by performing a stage vulcanization reaction.

The manufacturing method of the diaphragm of the present invention is characterized in that the second stage of oven vulcanization completely decomposes the peroxide, thereby preventing vulcanization from proceeding after molding and causing distortion during use. There is.

In a second aspect of the present invention, the tire flam part is composed of two cloth-covered rubber layers, and the two rubber layers are made of peroxide mixed in the tempering rubber layer. The two layers can be manufactured by vulcanization molding in a mold at the same time. The flow path side layer 2 in FIG. 2 is provided with a composition consisting of 50 to 100% by weight of rubber component 7-layer rubber and 50 to 100% by weight of EPDM rubber, and the valve drive section side layer 3 is provided with a composition consisting of 50 to 100% by weight of rubber component. is fluororubber 0-50
A rubber composition consisting of 100 to 50% by weight of EPDM rubber is placed, and the two layers of unvulcanized rubber are placed in a mold overlapping each other via the interface 4, and then gold is placed inside the mold. It is a tire plum that is integrally joined by heating and pressurizing and co-vulcanizing reaction with peroxide.

The tire flamm of the second aspect of the present invention is characterized by having two rubber layers in the diaphragm part, and the blending ratio of the fluororubber and EPDM of the rubber constituting each layer is different, and both rubber layers are not mixed. After being laminated in a vulcanized state, both rubber layers are simultaneously vulcanized and molded using peroxide vulcanization in gold.

In the diaphragm of the second aspect of the present invention, the peel strength of the interface can be significantly increased by co-vulcanizing with peroxide.

The diaphragm of the second aspect of the present invention is also co-cured with peroxide in the same way as the diaphragm of the first aspect, and the first stage of vulcanization is performed by heating at 140 to 190°C for 3 to 30 minutes under pressure with a mold. The reaction was carried out, and then removed from the mold and heated to 140
It is preferable to perform a second vulcanization reaction by heating at ~190° C. for 1 to 8 hours, followed by molding.

The effect of removing residual peroxide by the second stage of vulcanization is the same as in the first embodiment.

In the second aspect of the present invention, the fluororubber content in the rubber content is 50 to 100% by weight on the flow path side in contact with the fluid, and 50 to 0% by weight on the valve driving part side.

The most characteristic aspect is that the flow path side layer contains 100% by weight7
100% by weight EP is used for the valve drive part side layer.
A two-layer diaphragm using DM rubber can be used.

Even if these two rubber layers are made of completely different substances, the co-vulcanization molding with the above-mentioned peroxide prevents the two layers from peeling off due to vulcanization molding.

Furthermore, when co-vulcanizing two layers in which at least one layer is a mixed rubber layer containing both components and both layers have a common rubber component,
Due to the increased affinity, co-vulcanization with peroxide provides even stronger bonding between the layers.

The increased bond strength between the layers in such co-vulcanization is due to the use of peroxides, whereas the use of other crosslinking agents, e.g. sulfur, facilitates delamination. Occur.

As described above, the diaphragm of the second aspect of the present invention has a rubber layer containing a large amount of highly corrosion-resistant foam rubber on the surface that comes into contact with the corrosive fluid, and a rubber layer that has a high content of foam rubber with high corrosion resistance, and the back surface of the diaphragm has good elasticity and strength. , and inexpensive EP with good corrosion resistance to some extent.
Use DM to become familiar with diaphragms that take advantage of their respective characteristics.

However, in order to avoid peeling of the interface during use, the dissimilar rubber layer in the diaphragm molded product of the second aspect of the present invention is
It is desirable that the physical properties of the rubber, such as hardness and permanent deformation, be approximately the same.

The diaphragm of the present invention manufactured in this manner is characterized in that, by vulcanization molding using peroxide, a durable joint surface that is stable even at high temperatures can be obtained at the interface. Therefore, the diaphragm of the second aspect of the present invention can sufficiently withstand even when a high temperature fluid is flowed.

In the diaphragm of the second aspect of the present invention, it is desirable to have a layer with a high fluorine content and a thickness as thin as possible from the viewpoint of economy and runnability, and the thickness of the channel side layer is 10 to 50% of the total thickness.
thickness can be used.

As shown in Table 1, the diaphragm of the first embodiment of the present invention has corrosion resistance that is not much different from that of fluororubber alone, and as the content of fluororubber increases, the corrosion resistance slightly increases, and the sealing performance improves. The content of EPDM or EPM increases as the amount increases.

The diaslam of the first aspect of the present invention is very convenient in terms of process in that when it is charged into a mold, the peroxide compounded rubber composition can be extruded from an extruder into the mold and molded.

In the case of the diaphragm of the second aspect of the present invention, before putting it into a mold, two layers of peroxide-containing unvulcanized rubber molded into a circular shape are stacked on top of each other, and then put into a mold having a predetermined diaphragm shape. Vulcanization can be performed by heating under pressure.

The vulcanization molding of the diaphragm of the present invention is carried out in two ways due to the above-mentioned reasons.
It is preferable to implement it in stages.

In the diaphragm mold molding of the present invention, the first stage vulcanization conditions are as follows:
Under pressure by a mold, 140-190℃ 1 Preferably 1
At 60-170°C for 3-30 minutes, preferably 10-2
Heating for 5 minutes, then the second stage vulcanization conditions are: 140=11=~190℃1, preferably 150~160℃, after taking out from the mold.
It can be carried out for up to 8 hours, preferably 3 to 6 hours.

In the second stage oven vulcanization of the diaphragm of the present invention, it is desirable to decompose and remove residual peroxide as much as possible.

The peroxide used in the production of the diaphragm of the present invention is not particularly limited, and examples thereof include barokine ketal (barhegiza 3M, parhegiza O, barhegiza ), dialkyl perogizides (Percmill D, Verbutyl P1 Bar Hegiza 25B5 Verhexin 25B), etc. can be used.

As shown in FIG. 3, the diaphragm valve of the present invention is composed of a valve drive section 21, a diaphragm l, and a main body 23. .

and the tip 2 of the valve drive part in the center of the upper surface of the diaphragm.
6 is embedded and fixed.

-12= When the tip 26 of the valve drive 21 is moved downward, the central part 27 of the tire flamm 1 contacts the central plane 28 of the body 23 and closes the passages 29 and 30 of the body.

When using the diaphragm of the second aspect of the present invention, the diaphragm is installed with the layer with a larger fluororubber content facing the flow path side.

[Example] The tire plum of the present invention will be explained in more detail with reference to Examples.

A total of eight types of vulcanized rubber, two types of fluororubber, EPDM rubber, and five blend rubbers of fluororubber and EPDM rubber used in the present invention, were tested for mechanical properties and corrosion resistance in an electrolytic cell.

The formulation and vulcanization conditions of each rubber and the test method for the vulcanized rubber were as follows, and the results of the physical properties and corrosion resistance test were as shown in Table 1. Since the difference in hardness of the blended rubber obtained by these combinations is less than IO, there is no risk of peeling at the interface between the two layers.

<Composition of rubber used> ■Fluororubber G100 - Compound Tyer G100I 100 parts by weight Carbon black 20 parts by weight 2.5-dimethyl-2,
5 (Tertiary Butyl Veroquine) Hequin - 315 parts by weight Triallyl iso/annulate 4 parts by weight - Vulcanization conditions Vulcanize at 160°C for 15 minutes using a test piece mold press, remove from the mold and vulcanize at 160°C for 5 hours. A test piece was obtained.

■EPDM Rubber E70 - Compound EP24 100 parts by weight Zinc White No. 1
5 parts by weight stearic acid
] Part by weight Antioxidant MB 1 Part by weight Antioxidant RD ] Part by weight Carbon black FEF 82 parts by weight Paraffinic process oil 25 parts by weight Triallyl isocyanurate-1.
] Parts by weight Dicumyl peroxide 32 parts by weight Heart clay 5 parts by weight Vulcanization conditions 1st stage 160°C x 15 minutes 2nd stage in metal pot 160°C x S hours In the oven ■ Blend rubber l Fluororubber mainly composed of fluororubber - EPDM rubber Blend/Composition A composition obtained by blending the above formulations (1) and (2) at a ratio of 7 base rubber to EPDM rubber at a ratio of 80 + 20.

・Vulcanization conditions 1st stage 160℃X], 5 minutes 2nd stage in mold 16
In the oven at 0°C for 5 hours ■ Blend Rubber 2 Fluororubber mainly composed of EPDM rubber - EPDM blend rubber/composition A composition obtained by blending the formulations of (1) and (2) above at a ratio of fluororubber to EPDM rubber of 20:80.

・Vulcanization conditions 1st stage 160'CX1S minutes 2nd stage in mold 160℃X5 hours In oven ■Fluororubber G
A composition in which fluororubber Daiel G902 was blended in place of fluororubber Daiel G1001 in the formulation of 90 (1).

■Blend Rubber 3 - Composition" A composition obtained by blending the formulations of (1) and (2) above at a ratio of fluororubber and EPDM rubber of 80:20.

- Vulcanization conditions 1st stage 160℃ x 15 minutes In the mold 2nd stage 160℃ x 5 hours In the oven ■ Blend Rubber 4 - Compounding The above compounding ratio is such that the ratio of fluororubber and EPDM rubber is 60:40. A composition blended with.

・Vulcanization conditions 1st stage: 160°C x 15 minutes 2nd stage in mold: 160°C x 5 hours In oven ■ Blend Rubber 5 ・Composition The combination of ■ and ■ above is adjusted so that the ratio of fluororubber and EPDM rubber is 50:50. A composition blended with.

- Vulcanization conditions: 1st stage: 160°C x 15 minutes; 2nd stage in mold: 160°C x 5 hours; in oven <Physical property test method> ■Hardness (H6) Measured according to JISK-6301.

■Tensile strength (Tel) Measured according to JISK-6301.

■Elongation (E@) Measured according to JISK-6301.

(2) Compression set (C3) Measured according to JISK-6301 after standing at 100° for 122 hours.

■Corrosion resistance A test piece is immersed in a hypochlorous acid solution with an available chlorine concentration of 10%, and the weight change relative to the initial weight is measured in weight %. The immersion solution is updated every 24 hours and
Measure data for 2 days.

(The following is a blank space) From this table, it can be seen that by blending fluororubber, the corrosion resistance is improved more than expected from the blending ratio.

Moreover, from the results of Blend Rubber 2, it can be seen that when the fluororubber content is 20% by weight or less, the corrosion resistance is significantly reduced.

Example 1 A blended rubber compound was filled into a circular mold with a diameter of 71,100 mm and a thickness of 5 mm, heated at 160°C for 15 minutes while pressing, taken out from the mold, and heated at 160°C for 5 hours. A diaphragm was manufactured.

Example 2 Instead of Brush/Do Rubber 1 in Example 1, the same blend of IE PDM rubber-based Brush/Do Rubber 5 as used for the above test was used (with other conditions being the same). Manufactured the diaphragm.

Example 3 Blend rubber 1 was placed in the mold of Example 1 with an I of 2.5 mm.
Blend rubber 2 was charged in the remaining space of the mold above blend rubber 1, and a diaphragm was manufactured under the same conditions as in Example 1 while pressurizing.

When the obtained diaphragm was punched into a dumbbell shape perpendicular to the boundary surface 4 and the test piece was pulled and fractured while holding both ends, no boundary surface appeared on the fracture surface, and the boundary surface was a uniform layer of rubber. It was shown that they were equally bonded.

[Effect of the invention] The diaphragm valve of the present invention has the corrosion resistance of fluororubber and the EP
It has the sealing characteristics of DM or EPM and has the advantage of a long diaphragm life.

Moreover, since the diaphragm of the present invention can completely decompose peroxide, no distortion occurs during use.

Further, in the diaphragm of the second embodiment, since the fluororubber can be used efficiently by increasing the amount of fluororubber in the corrosion-resistant rubber layer, corrosion resistance can be achieved economically.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the tire nolla L of a diaphragm valve according to an embodiment of the present invention, FIG. FIG. 4 is a cross-sectional view of the tire phragm valve of the present invention, and FIG. 4 is a cross-sectional view of a conventional tire plum of the diaphragm valve. The symbols in the figure are 1: tire 7 ram, 2: flow path side blend rubber layer, 3: valve drive section side blend rubber layer, 4: boundary surface. Patent Applicant: Toyo Rubber Industries Co., Ltd. Representative: Mitsuru Uchiyama Figures 1 and 2? figure

Claims (1)

[Claims] 1. 25 to 95% by weight of fluororubber and EPDM or E
A rubber compound consisting of a composition consisting of 75 to 5% by weight of PM rubber as the rubber component and a peroxide mixed therein is heated in a mold and integrally molded by a vulcanization reaction caused by the peroxide. A diaphragm valve characterized by having a diaphragm. 2 In a diaphragm consisting of two layers, the channel side layer contains 50 to 100% by weight of fluororubber and EPDM or EPM.
A composition consisting of 50 to 0% by weight of rubber is used as the rubber component, a rubber layer containing peroxide is arranged, and the valve drive part side layer contains 0 to 50% by weight of fluororubber and 100% of EPDM or EPM rubber.
A composition consisting of ~50% by weight is used as a rubber component, a rubber layer containing peroxide is placed, and both rubber layers are heated simultaneously in a mold to integrate the two layers through a co-vulcanization reaction with the peroxide. A diaphragm valve characterized by having a diaphragm that is vulcanized and bonded. 3 Heat at 140 to 190°C for 3 to 30 minutes under pressure in a mold, then remove from the mold and heat to 140 to 190°C.
The diaphragm valve according to claim 1 or 2, wherein the diaphragm valve is integrally vulcanized and molded by heating at 90°C for 1 to 8 hours.