JPS62103113A - Diaphragm and its manufacture - Google Patents

Abstract

PURPOSE:To improve durability of a diaphragm, by a method wherein a semivulcanized rubber layer of a semiproduct of the diaphragm is vulcanized completely by making a part of the semiproduct of the diaphragm in a semivulcanized state, in which at least base cloth is buried, into a pressurized state. CONSTITUTION:An unvulcanized rubber layer is formed on base cloth by topping unvulcanized rubber. Hydrin rubber, acrylonitrile-butadiene copolymer (NBR) rubber, ethylene-propylene rubber, chloroprene rubber, silicone rubber, acrylic rubber and fluorine rubber are available as the rubber. Base cloth on which unvulcanized rubber layer like this has been formed is fitted to a mold by blanking the same into a predetermined shape, for example, a circle. The unvulcanized rubber which serves as a diaphragm body is charged to the base cloth 7 on which the unvulcanized rubber layer has been formed after the base cloth 7 has been fitted to the mold or prior to fitting of the same to the mold. After the unvulcanized rubber which serves as the diaphragm has been put into a bottom force 8 along with the base cloth 7 having the unvulcanized rubber layer, the same is heated by covering the same with a top force 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a diaphragm, and more particularly, to a method for manufacturing a diaphragm in which a base fabric is embedded in at least a portion of the diaphragm, such as a center plate portion of the diaphragm.

[Technical background of the invention]

As shown in Fig. 1, the diaphragm includes a center plate part 2 connected to the center plate 1 of the pressure-responsive device, a membrane part 3 that stands obliquely from the periphery of the center plate part 2, and a bead for attaching to the main body of the pressure-responsive device. 4, which operates in response to pressure from an operating shaft 5 of the center plate 1.

When manufacturing such a diaphragm 6, first, rubber that will become the main body of the diaphragm 6 is dumped onto the sheet-like base cloth 7, and the rubber is placed in a mold for forming an unvulcanized rubber layer.

That is, as shown in FIG. 2, a recess 20 for forming the center plate part 2 of the diaphragm 6, a film part forming part 30 for forming the film part 3 of the diaphragm 6, and a bead for forming the bead part 4. A base fabric 7 on which the unvulcanized rubber layer is formed is punched out so that it can be attached to the recess 20 of the lower mold 8 having the part forming part 40.
Attach. Next, the upper mold 9 having a recess, a film forming part, and a bead forming part is placed on the lower mold 8 at a position corresponding to the recess 20, the film forming part 30, and the bead forming part 40, and vulcanization is performed. do. Further, the base cloth 7 is attached to the recess 20.
After mounting on the base cloth 7, raw rubber may be placed on the base cloth 7, and the upper mold 9 may be placed thereon. In this manner, the base fabric 7 having the unvulcanized rubber layer and the unvulcanized product were placed in a mold, and then heated to completely vulcanize the rubber to manufacture the diaphragm 6.

As shown in FIG. 3, the top part 2 had a drawback in that unevenness 21 was formed corresponding to the weave of the base fabric 7, partly due to the thin rubber layer. If such unevenness 21 is formed on the membrane portion 3 of the diaphragm 6, when the diaphragm 6 is attached to a pressure-responsive device and used, wrinkles will occur in the concave portion of the uneven portion 21, causing cracks. It has the drawback of being easily formed (and having poor durability).

[Summary of the invention]

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to improve the durability of the diaphragm by smoothing the surface of the part where the base fabric is embedded in the diaphragm in which the base fabric is embedded as described above. It is something.

Therefore, the i! of the diaphragm according to the invention! ! According to the manufacturing method, an unvulcanized rubber layer is provided on a base fabric of a predetermined thickness, the base fabric formed into a predetermined shape is mounted in a mold together with the unvulcanized rubber that will become the diaphragm body, and the base fabric is heated. The method is characterized in that the buried portion is pressurized to completely vulcanize the semi-vulcanized rubber layer of the diaphragm semi-finished product.

According to the method for manufacturing a diaphragm according to the present invention, first, a semi-vulcanized diaphragm semi-finished product is formed, and then the part where the base fabric is buried, that is, the part where the base fabric is buried, is put under pressure to form the semi-vulcanized rubber. Since the layer is completely vulcanized, there is no unevenness on the surface of the buried portion of the base fabric, resulting in the advantage that it can be manufactured smoothly.

[Detailed description of the invention]

In the method for manufacturing a diaphragm according to the present invention, a base fabric is first topped with unvulcanized rubber.

Since the base fabric as described above is buried to improve the strength of the diaphragm, basically any fabric may be used as long as it improves the strength of the diaphragm. For example, it can be a heavy material such as Tetoron cloth, nylon cloth, cotton cloth, etc.

This base fabric is topped with unvulcanized rubber to form an unvulcanized rubber layer. Such unvulcanized rubber is preferably one that has good adhesion to the rubber that forms the main body of the diaphragm, and therefore is preferably a rubber similar to the above-mentioned rubber. Examples of such rubber include hydrin rubber, acrylonitrile-butadiene copolymer (NB
R) Rubber, ethylene-propylene rubber, chloroprene rubber, silicone rubber, acrylic rubber, fluororubber, etc. can be mentioned as examples.

The base fabric on which such an unvulcanized rubber layer is formed is shaped into a predetermined shape,
For example, it is punched out into a circular shape and mounted in a mold as shown in FIG. 2, for example.

After the base fabric 7 on which the unvulcanized rubber layer has been formed is mounted on the mold, or before mounting on the mold, the unvulcanized rubber that will become the diaphragm body is charged.

At this time, the unvulcanized rubber is charged into the mold so that the membrane portion 3 and bead portion 4 can be formed.

As described above, the unvulcanized rubber that forms the diaphragm body can be the same as the rubber topping the base fabric 7 described above.

The unvulcanized rubber that will become the diaphragm body is put into the lower mold 8 together with the base fabric 7 having the unvulcanized rubber layer, and then the upper mold 9 is placed on the mold and heated. When heated in this way, the unvulcanized rubber softens and flows, filling the voids formed in the mold,
It takes on the shape of a diaphragm and is vulcanized, resulting in a semi-finished diaphragm product.

In the present invention, unlike the conventional method, heating is stopped when the material is in a semi-vulcanized state without being completely vulcanized at this stage. That is, a semi-vulcanized diaphragm semi-finished product is formed.

The temperature at which the diaphragm semi-finished product in a semi-vulcanized state is formed is preferably 150 to 180°C. If the temperature is less than 150°C, the vulcanization reaction may be slow and take too much time, while if it exceeds 180°C, the vulcanization reaction will be too fast and it will be difficult to change to the semi-vulcanized state with the desired degree of vulcanization. This is because there is a risk that something will happen.

Furthermore, such vulcanization time is preferably 3 to 10 minutes. If it is less than 3 minutes, there is a risk that semi-vulcanized rubber with the desired degree of vulcanization may not be obtained, whereas if it exceeds 10 minutes, the vulcanization reaction will proceed too much and it will be difficult to obtain a semi-vulcanized state.

The vulcanization state of the semi-vulcanized rubber layer is preferably 50 to 80
% is better. The degree of vulcanization is less than 50%,
If it exceeds 80%, the semi-vulcanized rubber layer becomes too hard and cannot be used in the next process. In the step of smoothing the part of the diaphragm where the base fabric is buried, there is a risk that the unevenness may not be sufficiently eliminated.

Next, the semi-vulcanized diaphragm semi-finished product is taken out of the mold, at least the part where the base fabric 7 is buried is pressurized, and the semi-vulcanized rubber layer is removed while remaining in this pressurized state. Completely cure to form diaphragm 6.

This is to smoothen the part where the fabric is buried. Therefore, the pressure applied to the buried base fabric part is sufficient to smooth out the unevenness 21 on the surface of the buried base fabric part, and is a pressure that does not cause damage to the buried base fabric part. It is necessary. Typically, such pressure is between 1 and 50 kg
/aj. If it is less than I Kg/ca1, the surface of the buried part of the base fabric may not be smooth;
This is because if the pressure exceeds Kg/cJ, the pressure becomes too large and there is a risk of destroying the rubber layer and the like.

In this way, complete vulcanization is performed with pressure applied to at least the buried portion of the base fabric, and this vulcanization is preferably carried out at a temperature of 120 to 180° C. for 1 to 4 hours.

If the vulcanization temperature is less than 120°C, there is a risk that it will take too long for the semi-vulcanized rubber layer to cure.
If the temperature exceeds .degree. C., vulcanization and hardening will occur rapidly, so there is a risk that the surface smoothness will not be improved and the desired physical properties will not be changed.

Examples will be described below.

Example First, a cotton base cloth with a thickness of 1.00 mm was prepared, and after topping it with NBR rubber to a thickness of 0.5 mm, it was punched out so that it could be attached to the mold shown in Figure 2. Nuki,
The mold was unvulcanized and mounted. Cover with upper mold 9 and heat to 170℃
, and heated for 4 minutes to produce a semi-vulcanized diaphragm semi-finished product. The degree of vulcanization of the rubber layer of this diaphragm semi-finished product is
It was about 70%.

Next, the diaphragm semi-finished product is removed from the mold and the fourth
As shown in the figure, the membrane part 3 is attached to the membrane part 3 which is the part where the base fabric is buried.
An iron plate 10 of the same shape is placed on the membrane part 3 and heated to 30K.
A pressure of g/ci was applied and the semi-vulcanized rubber layer was completely vulcanized by heating at 150° C. for 2 hours.

The membrane portion of the diaphragm manufactured in this manner was smoother than the conventional membrane, and exhibited durability of 500 hours in a durability test.

For comparison, the same durability test was conducted on a conventional diaphragm that was completely vulcanized in the mold under similar conditions, and the durability was 200 to 300 hours. As explained above, according to the diaphragm manufacturing method of the present invention, a diaphragm semi-finished product in a semi-vulcanized state is manufactured, and then it is completely cured while applying pressure to the buried part of the base fabric, so that the surface of the buried part of the base fabric is completely cured. The advantage is that the smoothness is improved and therefore the durability of the diaphragm produced is increased.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a diaphragm, FIG. 2 is a cross-sectional view showing an example of a method for manufacturing a diaphragm, FIG. 3 is a cross-sectional view of a conventional diaphragm buried in the base fabric, and FIG. It is a sectional view for explaining a complete vulcanization process. 2...Center plate part, 3...Membrane part, 4.
...Bead portion, 6...Diaphragm, 7...Base fabric, 21...Irregularities, 8...Lower mold, 9...Upper mold. Figure 7 Mouth Figure 2 Figure 4 Procedural amendment written Jio 6th call of Showa November 29th Uga Dobu-dono 1, 11 Ushi no Yo 1985 Patent Application No. 242696 2 Title of the invention Diaphragm and its manufacturing method 3, relationship with the case of the person making the amendment Patent applicant address: Tokyo Parts JIl Kousuke Oita 2-11-20
No. 4, Agent 〒102 1i! ! 03-264-3
566 Specification Name of the invention Diaphragm and its manufacturing method Claims (11 A diaphragm in which a base cloth is embedded at least in a part of a rubber layer of a predetermined shape, in which a semi-vulcanized rubber layer is provided in the base cloth. A diaphragm is characterized in that it has a base fabric buried part that is completely vulcanized and smoothed by applying pressure to the base fabric. The base fabric is mounted in a mold together with the unvulcanized rubber that will become the diaphragm body, and heated to form a semi-vulcanized diaphragm semi-finished product. At least one of the semi-vulcanized diaphragm semi-finished products is A method for manufacturing a diaphragm, characterized in that the semi-vulcanized rubber layer of the semi-vulcanized diaphragm product is completely cured by applying pressure to the part where the base fabric is buried.Detailed Description of the Invention (Technical Field of the Invention) The present invention relates to a diaphragm and a method for manufacturing the same, and more particularly to a diaphragm in which a base fabric is embedded in at least a portion of the diaphragm, such as a center plate portion of the diaphragm, and a method for manufacturing the same. As shown in FIG. 1, there is a center plate part 2 connected to the center plate 1 of the pressure-responsive device, a membrane part 3 that stands obliquely from the periphery of the center plate part 2, and a bead part 4 for attaching to the main body of the pressure-response device. The diaphragm 6 is actuated in response to pressure from the actuating shaft 5 of the center plate 1. When manufacturing such a diaphragm 6, first, a sheet-like base fabric 7 is topped with rubber, which will become the main body of the diaphragm 6. After forming an unvulcanized rubber layer and punching out the base fabric 7 topped with the unvulcanized rubber into a predetermined shape, the base fabric 7 is mounted in a mold. That is, as shown in FIG. As shown in FIG. A base cloth 7 on which the unvulcanized rubber layer is formed is punched out so that it can be attached to the recess 20 of the mold 8.
Next, an upper mold 9 having a recess, a film forming part, and a bead forming part in the same manner as the recess 20, the film forming part 30, and the bead forming part 40 of the lower mold 8 is installed. Cover and vulcanize. Further, the base cloth 7 is attached to the recess 20.
After mounting on the base cloth 7, raw rubber may be placed on the base cloth 7, and the upper mold 9 may be placed thereon. In this manner, the base fabric 7 having the unvulcanized rubber layer and the unvulcanized product were placed in a mold, and then heated to completely vulcanize the rubber to manufacture the diaphragm 6. The part of the diaphragm 6 manufactured by this method in which the base fabric 7 is buried, for example, the center plate part 2, has a thin rubber layer as shown in FIG. There was a drawback that unevenness 21 was formed corresponding to the eyes. If such unevenness 21 is formed on the membrane portion 3 of the diaphragm 6, when the diaphragm 6 is attached to a pressure-responsive device and used, wrinkles will occur in the concave portion of the uneven portion 21, causing the crank to become unstable. This has the drawback of being more likely to occur and resulting in poor durability. [Summary of the Invention] The present invention has been made in view of the above-mentioned points, and improves the durability of the diaphragm by smoothing the surface of the part where the base fabric is embedded in the diaphragm in which the base fabric is embedded as described above. The purpose is to Therefore, in the diaphragm according to the present invention, in a diaphragm in which a base fabric is embedded in at least a portion of a rubber layer having a desired shape, the base fabric embedded portion in which a semi-vulcanized rubber layer is provided in the base fabric is pressurized, It is characterized by having a completely vulcanized and smooth buried part of the base fabric. Furthermore, according to the method for manufacturing a diaphragm according to the present invention,
An unvulcanized rubber layer is provided on a base fabric of a predetermined thickness, and the base fabric formed into a predetermined shape is attached to a mold together with the unvulcanized rubber that will become the diaphragm body, and heated to produce a semi-vulcanized diaphragm semi-finished product. After forming, the semi-vulcanized rubber layer of the semi-vulcanized diaphragm semi-finished product is completely vulcanized by pressurizing at least the part where the base fabric is embedded in the semi-vulcanized semi-vulcanized diaphragm semi-finished product. It is something. According to the diaphragm according to the present invention, since the portion of the diaphragm embedded in the base fabric is smoothed, there is an advantage that durability is improved. Furthermore, according to the method for manufacturing a diaphragm according to the present invention,
First, after forming a semi-vulcanized diaphragm semi-finished product,
Since the semi-vulcanized rubber layer is completely vulcanized by applying pressure to the part where the base fabric is buried, that is, the part where the base fabric is buried, there is no unevenness on the surface of the part where the base fabric is buried, and the product can be manufactured smoothly. Take advantage of being able to. [Detailed Description of the Invention] In the method for manufacturing a diaphragm according to the present invention, a base fabric is first topped with unvulcanized rubber. Since the base fabric as described above is buried to improve the strength of the diaphragm, basically any fabric may be used as long as it improves the strength of the diaphragm. For example, it can be a tangible material such as Tetoron cloth, nylon cloth, cotton cloth, etc. This base fabric is topped with unvulcanized rubber to form an unvulcanized rubber layer. Such unvulcanized rubber is preferably one that has good contact with the rubber that forms the main body of the diaphragm, and therefore is preferably a rubber similar to the above-mentioned rubber. Examples of such rubber include hydrin rubber, acrylonitrile-butadiene copolymer (NB
R) Rubber, ethylene-propylene rubber, chloroprene rubber, silicone rubber, acrylic rubber, fluororubber, etc. can be mentioned as examples. The base fabric on which such an unvulcanized rubber layer is formed is shaped into a predetermined shape,
For example, it is punched out into a circular shape and mounted in a mold as shown in FIG. 2, for example. After the base fabric 7 on which the unvulcanized rubber layer has been formed is mounted on the mold, or before mounting on the mold, the unvulcanized rubber that will become the diaphragm body is charged. At this time, the unvulcanized rubber is charged into the mold so that the membrane portion 3 and bead portion 4 can be formed. As described above, the unvulcanized rubber that forms the diaphragm body can be the same as the rubber topping the base fabric 7 described above. The unvulcanized rubber that will become the diaphragm body is put into the lower mold 8 together with the base fabric 7 having the unvulcanized rubber layer, and then the upper mold 9 is placed on the mold and heated. When heated in this way, the unvulcanized rubber softens and flows, filling the voids formed in the mold, and
It takes on the shape of a diaphragm and is vulcanized, resulting in a semi-finished diaphragm product. In the present invention, unlike the conventional method, heating is stopped when the material is in a semi-vulcanized state without being completely vulcanized at this stage. That is, a semi-vulcanized diaphragm semi-finished product is formed. The temperature at which the diaphragm semi-finished product in a semi-vulcanized state is formed is preferably 150 to 180°C. If the temperature is less than 150°C, the vulcanization reaction may be slow and take too much time, while if it exceeds 180°C, the vulcanization reaction will be too fast and it will be difficult to change to the semi-vulcanized state with the desired degree of vulcanization. This is because there is a risk that something will happen. Furthermore, such vulcanization time is preferably 3 to 10 minutes. If it is less than 3 minutes, there is a risk that semi-vulcanized rubber with the desired degree of vulcanization may not be obtained, whereas if it exceeds 10 minutes, the vulcanization reaction will proceed too much and it will be difficult to obtain a semi-vulcanized state. The vulcanization state of the semi-vulcanized rubber layer is preferably 50 to 80
% is better. The degree of vulcanization is less than 50%,
If it exceeds 80%, the semi-vulcanized rubber layer becomes too hard and cannot be used in the next process. In the step of smoothing the buried portion of the Guyaflam base fabric, there is a risk that the unevenness may not be sufficiently eliminated. Next, the semi-vulcanized diaphragm semi-finished product is taken out of the mold, at least the part where the base fabric 7 is buried is pressurized, and the semi-vulcanized rubber layer is removed while remaining in this pressurized state. Completely cure to form diaphragm 6. Such a vulcanization step smoothes the buried portion of the base fabric by vulcanizing and hardening the portion under pressure. Therefore, the pressure applied to the buried base fabric part is sufficient to smooth out the unevenness 21 on the surface of the buried base fabric part, and is a pressure that does not cause damage to the buried base fabric part. It is necessary. Typically such pressure is between 1 and 50 Kg/ca. If the pressure is too high, there is a risk that the surface of the buried part of the base fabric will not be smooth, while if it exceeds 50kg/-, the pressure will become too large and there is a risk of destroying the rubber layer, etc. . In this way, complete vulcanization is performed with pressure applied to at least the buried portion of the base fabric, and this vulcanization is preferably carried out at a temperature of 120 to 180° C. for 1 to 4 hours. If the vulcanization temperature is less than 120°C, there is a risk that it will take too long for the semi-vulcanized rubber layer to cure.
This is because if the temperature exceeds .degree. C., the surface smoothness may not be improved due to rapid WL hardening. If the vulcanization time is 1 hour, there is a risk that the semi-vulcanized rubber layer will not be completely cured, while if it exceeds 4 hours, the vulcanization will progress too much and become hard, resulting in less desired physical properties. There is a possibility that it will not change. The invention also provides a diaphragm thus manufactured. That is, in a diaphragm as shown in FIG. 1, in which the base fabric 7 is embedded in all or part of the center plate part 2, the membrane part 3, and the bead 4, at least the part where the base fabric 7 is embedded is smoothed. , with improved durability. That is, by forming a semi-vulcanized rubber layer on the base fabric 7 and completely vulcanizing this rubber layer under pressure using the method described above, the rubber embedded portion is made into a smooth rubber layer. ing. Examples will be described below. Example First, a cotton base fabric with a thickness of 1.00 mm was prepared, and after topping it with NBR rubber to a thickness of 0.5 mm, it was punched out so that it could be attached to the mold shown in Figure 2. The mold was removed and unvulcanized was mounted in the mold. Cover with upper mold 9 and heat to 170°C
A semi-vulcanized diaphragm semi-finished product was produced by heating for 14 minutes. The degree of vulcanization of the rubber layer of this diaphragm semi-finished product is
It was about 70%. Next, the diaphragm semi-finished product is removed from the mold and the fourth
As shown in the figure, the membrane part 3 is attached to the membrane part 3 which is the part where the base fabric is buried.
An iron plate 10 having the same shape as 1 is placed on the membrane part 3, and 30
The semi-vulcanized rubber layer was completely vulcanized by heating at 150° C. for 2 hours so that a pressure of Kg/cIA was applied. The membrane portion of the diaphragm manufactured in this manner was smoother than the conventional membrane, and exhibited durability of 500 hours in a durability test. For comparison, the same durability test was conducted on a conventional diaphragm that was completely vulcanized in the mold under similar conditions, and the durability was 200 to 300 hours. [Effects of the Invention] As explained above, according to the diaphragm manufacturing method of the present invention, a diaphragm semi-finished product in a semi-vulcanized state is manufactured and then completely vulcanized while applying pressure to the buried portion of the base fabric. The smoothness of the surface of the buried portion of the base fabric is improved, resulting in the advantage that the durability of the manufactured diaphragm is improved. Brief description of the drawings Figure 1 is a cross-sectional view of a diaphragm, Figure 2 is a cross-sectional view showing an example of a method for manufacturing a diaphragm, Figure 3 is a cross-sectional view of a conventional diaphragm buried in the base fabric, and Figure 4 is a cross-sectional view of the diaphragm. FIG. 3 is a cross-sectional view for explaining a complete vulcanization step of the manufacturing method of the invention. 2... Center plate part, 3... Membrane part, 4...
Bead portion, 6...Diaphragm, 7...Base fabric,
21...Irregularities, 8...Lower mold, 9...Upper mold.

Claims (1)

[Claims] (1) An unvulcanized rubber layer is provided on a base fabric of a predetermined thickness, and the base fabric formed into a predetermined shape is attached to a mold together with the unvulcanized rubber that will become the diaphragm body, and heated to form a semi-vulcanized diaphragm. After forming the semi-finished product, pressurize at least a portion of the semi-vulcanized diaphragm semi-finished product in which the base fabric is buried to completely cure the semi-vulcanized rubber layer of the semi-vulcanized diaphragm product. Characteristic diaphragm manufacturing method