WO2015015874A1 - Production method for vulcanized rubber molded article, and spacer - Google Patents

Abstract

Provided are a production method for vulcanized rubber molded article, with which high quality product fabrication is possible with reduced labor, and a spacer which is compressible in the thickness direction and the width direction, so as to provide a spacer suited to utilization in this production method.

Description

Method for producing vulcanized rubber molded body and spacer

The present invention relates to a method for producing a vulcanized rubber molded article and a spacer, and more specifically, a vulcanized rubber molded article by performing vulcanization in order along the length direction of a strip-shaped unvulcanized rubber molded article. A method for producing a vulcanized rubber molded body for producing a body, and in the width direction and the thickness direction of an unvulcanized rubber molded body when vulcanizing by pressing the unvulcanized rubber molded body in the thickness direction The present invention relates to a spacer used to regulate deformation.

DESCRIPTION OF RELATED ART Conventionally, the conveying apparatus for conveying mineral resources, such as iron ore, coal, cement, and crushed stone for a long distance, and the conveyor belt used around the pulley of the said conveying apparatus are known widely.
As this type of transporting device, a device that carries and transports personnel for the movement of passengers within a station premises or in an airport, or the movement of a player between holes at a golf course is widely known.
The conveyor belt used in such a conveying device is usually formed in an endless shape by joining both ends of a long belt-like vulcanized rubber molded body.

In addition to conveyor belts, long belt-shaped vulcanized rubber moldings are used for rubber crawlers such as agricultural vehicles and snow removal vehicles, rubber floor materials laid on the floor of railway vehicles, and rivers. It is also used for tube-like rubber weirs and the like.

In general, a sheet-like vulcanized rubber molded body is produced by a method in which a sheet-like unvulcanized rubber molded body is heated and pressurized with a hot press to vulcanize the unvulcanized rubber molded body.
However, the long belt-like vulcanized rubber molded body as described above may have a length that does not fit between the hot plates of a hot press machine, for example.
In that case, the vulcanized rubber molded body is a “feed firing” in which a belt-shaped unvulcanized rubber molded body is conveyed in the length direction and the unvulcanized rubber molded body is vulcanized with a heat press in order from the end. It is produced by a method called "" (see Patent Document 1 below).
Further, the long belt-like vulcanized rubber molded body as described above is a member for pressing the unvulcanized rubber molded body with a metal drum and a metal endless belt instead of a hot platen of a hot press machine. It is also produced by a method called “rotocure continuous vulcanization” (see Patent Document 2 below).

Japanese Unexamined Patent Publication No. 2008-063058 Japanese Unexamined Patent Publication No. 2000-043070

When producing a vulcanized rubber molded body by pressurizing and heating the unvulcanized rubber molded body, if there is a part where the pressure is not sufficiently applied to the unvulcanized rubber molded body, the part becomes sponge-like. (Hereinafter also referred to as “sponge failure”).
Therefore, the vulcanized rubber molded body is subjected to hot pressing by placing spacers made of rectangular metal bars or the like on both sides in the width direction of the band-shaped unvulcanized rubber molded body, and the unvulcanized rubber molded with the spacers. It is preferable that the side pressure on the body is secured so that sponge defects do not occur at the side edge.

However, in this case, since it is necessary to apply sufficient pressure in the thickness direction to the unvulcanized rubber molded body, the vulcanized rubber molded body uses a metal rod or the like that is thinner than the unvulcanized rubber molded body as a spacer. Need to be made.
Then, the unvulcanized rubber molded body is pressed by the hot plate before the hot plate starts to press the spacer.
Therefore, simply using a spacer may cause the unvulcanized rubber to overflow to the outside of the spacer through the space between the hot platen and the spacer.

The overflowed rubber may drop off and remain in the hot press when the vulcanized portion of the unvulcanized rubber molded body is taken out from the hot press.
The rubber remaining in the hot press machine may cause adhered foreign matter and indentations on the vulcanized rubber molded body.
Even if the rubber overflowed by the hot press machine does not fall off when the vulcanized portion is carried out of the hot press machine, the final vulcanized rubber molded body is burred.
When many burrs are generated during the production of a vulcanized rubber molded product, it may be necessary to work for a long time to remove the burrs.
That is, the conventional method for producing a belt-like vulcanized rubber molded article has a problem that it is difficult to produce a high-quality product by suppressing the appearance defect of the product while suppressing the labor required. ing.
Such a problem is a common problem not only in “feed baking” by a hot press machine but also in “rotocure continuous vulcanization”.

The present invention aims to solve the above problems, and a method for producing a vulcanized rubber molded body capable of producing a high-quality product while suppressing defective appearance while suppressing labor required, Also, it is an object to provide a spacer suitable for use in such a manufacturing method.

The present invention relating to a method for producing a vulcanized rubber molded body for solving the above-mentioned problems is that the unvulcanized rubber molded body is disposed in the thickness direction on one side and the other side of a belt-shaped unvulcanized rubber molded body. A pressure member for pressurizing is disposed, the unvulcanized rubber molded body is vulcanized by heating the unvulcanized rubber molded body while being pressurized with the pressure member, and the vulcanized A method for producing a vulcanized rubber molded body, which is sequentially performed along the length direction of an unvulcanized rubber molded body to produce a band-shaped vulcanized rubber molded body, Spacers for restricting deformation in the width direction and the thickness direction are arranged on both outer sides in the width direction of the unvulcanized rubber molded body, and the vulcanization is performed. It is characterized by using a spacer that can expand and contract in the width direction of the vulcanized rubber molding.

Further, the present invention relating to the spacer for solving the above-described problem is that the unvulcanized rubber molded body is vulcanized by heating the band-shaped unvulcanized rubber molded body while pressing in the thickness direction. When producing a vulcanized rubber molded body, the unvulcanized rubber molded body is arranged on both outer sides in the width direction so as to restrict deformation in the width direction and thickness direction of the unvulcanized rubber molded body due to the pressurization. It is used, and is characterized by being freely stretchable in the thickness direction and the width direction.

In the present invention, a spacer that can expand and contract in the pressurizing direction of the unvulcanized rubber molded body is used for producing a belt-like vulcanized rubber molded body.
Therefore, in the method for producing a vulcanized rubber molded article of the present invention, an unvulcanized rubber molded article can be used even when a thick spacer is used as compared with a case where a spacer having no elasticity such as a metal spacer is used. In contrast, a sufficient pressure can be applied in the thickness direction.
Therefore, in the method for producing a vulcanized rubber molded body of the present invention, not only a spacer having a thickness smaller than that of the unvulcanized rubber molded body but also a spacer having a thickness larger than that of the unvulcanized rubber molded body is used. Can do.
Therefore, in the present invention, when the unvulcanized rubber molded body is pressurized with the pressure member, the timing at which the pressure member starts to press the spacer can be accelerated compared to the case where a metal spacer or the like is used.
That is, according to the present invention, it is possible to eliminate a gap between the spacer and the pressure member, which may cause rubber to enter, at a relatively early stage when the unvulcanized rubber molded body is vulcanized.
Moreover, since the spacer of the present invention is expandable and contractible in the width direction of the unvulcanized rubber molded body as described above, the unvulcanized rubber molded body is pressed by the pressure member and tends to deform wide. In doing so, the followability to the side shape of the unvulcanized rubber molded article can be exhibited.
Therefore, the spacer of this invention can suppress that the pressure received from an unvulcanized rubber molding at the time of vulcanization of an unvulcanized rubber molding concentrates locally.
Thus, the spacer of the present invention has a function of quickly contacting the pressure member during vulcanization of the unvulcanized rubber molded body, and a strong pressure between the pressure member and the pressure received from the unvulcanized rubber molded body. And the function of preventing local concentration of pressure received from the unvulcanized rubber molded body.
Therefore, in the present invention, the overflow of rubber during the production of the vulcanized rubber molded product is suppressed, and it is possible to suppress adhesion foreign matter and indentation in the vulcanized rubber molded product, and the vulcanized rubber molded product. It is possible to reduce the time and effort of deburring after the manufacture of the product.

That is, according to the present invention, a method for producing a vulcanized rubber molded body capable of producing a high-quality product with less appearance defects while suppressing labor, and suitable for use in such a production method. Spacers may be provided.

The schematic perspective view showing the one aspect | mode of the manufacturing method of a vulcanized rubber molding. FIG. 2 is a cross-sectional view taken along line II in FIG. 1. The principal part enlarged view explaining the function of a spacer, enlarging the broken line Y of FIG. The principal part enlarged view explaining the function of another spacer. The principal part enlarged view which shows a mode that the several spacer was arrange | positioned. The schematic sectional drawing which showed the various aspects of the spacer. Schematic showing the other aspect of the manufacturing method of a vulcanized rubber molding. Schematic showing the other aspect of the manufacturing method of a vulcanized rubber molding.

Hereinafter, an embodiment of the present invention will be described by taking as an example the case where the vulcanized rubber molded body produced by the production method of the present invention is a flat belt-like conveyor belt.
FIG. 1 is a perspective view schematically showing a state in which a long belt-shaped unvulcanized rubber molded body 1 for forming the conveyor belt is vulcanized in order in the length direction using a hot press machine 5. FIG. 2 is a diagram showing an outline of a cross section taken along line II in FIG.

In the conveyor belt manufacturing method of the present embodiment, the following steps (a) and (b) are alternately performed to form a vulcanized rubber molded body (conveyor belt).

(A) A part of the strip-shaped unvulcanized rubber molded body 1 is heated to a predetermined temperature while applying a predetermined pressure in the thickness direction TD by the hot press 5 and the heating under this pressure is performed for a predetermined time. A vulcanization step that is carried out to vulcanize the part.
(B) The unvulcanized rubber molded body 1 is moved along its length direction LD, and the vulcanized part is demolded from the hot press 5 as a vulcanized portion 10b and the vulcanized portion 10b. The transfer process which supplies the unvulcanized location 10a following to a hot press machine.

That is, after the transfer step, a vulcanization step for vulcanizing the unvulcanized portion 10a of the strip-shaped unvulcanized rubber molded body 1 is newly performed.
As described above, in the present embodiment, the conveyor belt is formed by vulcanizing the substantially entire length of the unvulcanized rubber molded body 1 by a method of repeating vulcanization and demolding / transfer.

In the present embodiment, the unvulcanized rubber molded body 1 is vulcanized by the hot press 5 in a posture in which the surface direction is substantially horizontal.
That is, the hot press machine 5 has a pair of upper and lower heating plates as pressure members for pressing the unvulcanized rubber molded body 1 in the thickness direction, and the unvulcanized rubber molded body 1 is moved from the upper surface side. An upper heating platen 50a for heating and pressurizing and a lower heating platen 50b for heating and pressurizing the unvulcanized rubber molded body 1 from the lower surface side are provided.
Each of the upper heating platen 50a and the lower heating platen 50b is formed in a rectangular plate shape, and is heated by pressing the rectangular plate surface for pressurizing and heating the unvulcanized rubber molded body 1 in the vertical direction. It is provided in the machine 5.

In the present embodiment, the lower hot platen 50b is hot-pressed in a state where the platen surface is directed vertically upward and the longitudinal direction of the platen surface is the length direction LD of the unvulcanized rubber molded body 1. The machine 5 is arranged.
The upper heating platen 50a is common to the lower heating platen 50b in that the longitudinal direction of the platen surface is the longitudinal direction LD of the unvulcanized rubber molded body 1 and is arranged in the heat press.
On the other hand, the upper heating platen 50a is different from the lower heating platen 50b in that the platen surface is directed downward in the vertical direction and can be moved up and down and arranged in the heat press machine 5.
In the vulcanization process, the upper heating platen 50a is lowered and a predetermined pressure is applied to the unvulcanized portion 10a sandwiched between the lower heating platen 50b and the heat of the heating plates 50a and 50b. As a result, the unvulcanized portion 10a is heated.
The transfer step is performed by raising the upper heating platen 50a and releasing the pressure on the vulcanized portion 10b that has been pressurized and heated for a predetermined time in the vulcanizing step, and then by an appropriate sheet moving means. This is performed by moving the unvulcanized rubber molded body 1 by a predetermined distance in the length direction LD.

The unvulcanized rubber molded body 1 has a length that is several times or more the length of the surface of the upper heat platen 50a and the lower heat platen 50b, and the surface of the plate as a dimension in the width direction WD. Has a size smaller than the width of
In other words, the lower heating platen 50b of the present embodiment is configured such that when the unvulcanized location 10a newly introduced into the heat press by the transfer process is placed on the platen surface, the unvulcanized location 10a. The extra space is formed on both sides in the width direction.

In the present embodiment, the spacer 20 is disposed in the surplus space on the lower heating platen, and the spacer 20 is sandwiched between the upper and lower heating plates (50a, 50b) together with the unvulcanized rubber molded body 1 to be unvulcanized. The deformation of the rubber molded body 1 in the width direction and the thickness direction is restricted.
(In FIG. 1, the illustration of the spacer is omitted.)
Moreover, in the present embodiment, as the spacer 20, a spacer that can be expanded and contracted in the thickness direction and the width direction is used.

Note that the spacer 20 disposed on the left side of the unvulcanized rubber molded body 1 and the spacer 20 disposed on the right side of the unvulcanized rubber molded body 1 in the front view of FIG. The spacer 20 in the form has a square bar shape made entirely of a rubber elastic body.
Since the spacer 20 in the present embodiment is a rubber elastic body as a whole, it can be expanded and contracted not only in the thickness direction TD and the width direction WD but also in the length direction LD.

The spacer 20 of the present embodiment is thinner than the unvulcanized rubber molded body 1 and has a length exceeding the length D1 of the board surface of the lower heating board 50b.
That is, in this embodiment, the spacer 20 longer than the hot platen length in the length direction of the unvulcanized rubber molded body 1 is used.
The spacer 20 in the present embodiment is arranged over the entire surface of the lower heating platen 50b, and the distance W1 between the spacers arranged on the left and right sides of the unvulcanized rubber molded body 1 is not added between them. It arrange | positions on the board surface of the lower heating board 50b so that it may become slightly wider than the width | variety W2 of the vulcanized rubber molded object 1. FIG.
Therefore, after the transfer step, when the upper heating platen 50a is lowered and its surface comes into contact with the upper surface of the unvulcanized rubber molded body 1 (FIG. 3 (a)), the platen surface and the spacer in the thickness direction. 20 has a slight clearance CRt (hereinafter also referred to as “thickness clearance CRt”) and a slight clearance CRw between the unvulcanized rubber molded body 1 and the spacer 20 in the width direction. (Hereinafter also referred to as “width clearance CRw”).

In the present embodiment, as described above, the spacer 20 made entirely of a rubber elastic body is used. Therefore, by generating tension by pulling in the length direction, the thickness and width of the spacer 20 are slightly reduced. The thickness clearance CRt and the width clearance CRw can be finely adjusted according to the magnitude of the tension.
In general, a rubber elastic body does not have a linear correlation between stress and strain.
That is, when an attempt is made to deform a rubber elastic body with the same force, the amount of deformation is usually greatly different between a rubber elastic body to which a certain amount of stress has already been applied and a rubber elastic body to which no stress has been applied.
Therefore, in this embodiment, by applying tension to the spacer 20 and applying distortion, the elastic deformation behavior in the thickness direction and the width direction of the spacer 20 is made different from the case where no tension is applied. Can do.
From this, in this embodiment, it becomes possible to adjust how the side pressure is applied to the unvulcanized rubber molded body 10a during the vulcanization step by applying tension to the spacer 20.

In the unvulcanized rubber molded body 1, pressure is applied in the thickness direction by further lowering the upper heating platen 50 a from the state where the surface of the upper heating platen 50 a is in contact with the upper surface (FIG. 3A), The unvulcanized rubber molded body 1 is deformed in the direction of widening.
The spacer 20 is also deformed in the direction of widening when the upper heating platen 50a is further lowered from the time when the upper heating platen 50a reaches the upper surface (FIG. 3B).
Thereby, in the vulcanization step, a strong pressure can be applied between the side surface of the spacer 20 and the side surface of the unvulcanized rubber molded body 1, and the occurrence of defective sponge can be suppressed. .
In addition, the spacer 20 can convert the pressure generated between the unvulcanized rubber molded body 1 into a contact force with the upper heating platen 50a and the lower heating platen 50b.

In the present embodiment, the thickness of the unvulcanized rubber molded body 1 is used because a spacer that can expand and contract in the thickness direction is used instead of a metal spacer that hardly exhibits elastic deformation such as stainless steel or steel. In order to apply a predetermined pressure in the direction, a spacer thicker than a metal spacer can be used.
Therefore, in this embodiment, the timing at which the thickness clearance CRt disappears can be advanced compared to the case where a metal spacer is used.
Therefore, in this embodiment, it can suppress that a part of unvulcanized rubber molded object 1 deform | transformed into the width | variety enters into thickness clearance CRt, and results in generating a burr | flash on a conveyor belt.
In addition, although the method of using a metal spacer and ensuring sufficient width direction clearance enables suppression of a burr | flash, there exists a high possibility that a sponge defect will be produced in the side edge part of a conveyor belt.

In the present embodiment, since a spacer that can expand and contract in the thickness direction is used, for example, as shown in FIG. 4A, the start of pressurization of the spacer 20 by the upper heating platen 50a is not performed by the upper heating platen 50a. It is possible to precede the timing of starting pressurization of the vulcanized rubber molded body 1.
In this case, it is necessary to ensure the width direction clearance CRw to be large to some extent. However, since the spacer of this embodiment can be expanded and contracted in the width direction by the pressure applied in the thickness direction, it is not added during the vulcanization process. It is easier to ensure the side pressure of the vulcanized rubber molded body than a metal spacer.
Therefore, in the present embodiment, it is possible to suppress the occurrence of defective sponge while more reliably suppressing the generation of burrs.

Further, the hot press hot platen does not have a uniform smooth surface, and may have some unevenness.
Therefore, when a metal spacer is used, it is easy to form a low-pressure portion between the spacer and the upper heating plate in the vulcanization process, and some components of the unvulcanized rubber molded body are inside the spacer through the portion. However, in the present embodiment, a spacer made of a rubber elastic body and having excellent elastic deformability on the surface is used.
Therefore, also from this, according to the present embodiment, it is possible to suppress the formation of burrs due to rubber overflow or the like.
Moreover, since the spacer 20 can be expanded and contracted in the width direction, the spacer 20 is excellent in followability to the side shape of the unvulcanized rubber molded body.
Therefore, the spacer 20 can easily equalize the lateral pressure generated between the unvulcanized rubber molded body in the length direction and prevent the rubber from overflowing due to local high pressure. Can do.
In the vulcanization step, another spacer may be arranged outside the spacer 20 to back up the spacer 20 to apply a side pressure to the unvulcanized rubber molded body 1, in which case The backup spacer need not be stretchable in the thickness direction.
In the present embodiment, a metal square bar that is thinner than the spacer 20 may be used as a backup spacer.
By using the backup spacer, it is possible to suppress the spacer 20 for applying a side pressure to the unvulcanized rubber molded body 1 from moving outward in the width direction due to the side pressure.
In the vulcanization process, two or more sets of such backup spacers can be used.
More specifically, it is preferable that the vulcanization step is performed by arranging a plurality of backup spacers so that there is no excess space on the surface of the lower heating platen 50b.

As described above, the method for producing a vulcanized rubber molded body according to the present embodiment includes a spacer for regulating deformation of the unvulcanized rubber molded body in the width direction and the thickness direction due to pressurization. The vulcanization may be carried out by arranging a plurality of them on both outer sides in the width direction of the molded body.
This point will be described with reference to FIG.
FIG. 5 shows a state in which three spacers are arranged on both outer sides in the width direction of the unvulcanized rubber molded body.
Among the three spacers illustrated in FIG. 5, a spacer 20 x (hereinafter also referred to as “first spacer”) that is disposed closest to the unvulcanized rubber molded body 1 and is in direct contact with the unvulcanized rubber molded body 1. ) Is a spacer that can expand and contract in the thickness direction and the width direction.
The first spacer 20x may be entirely formed of a rubber elastic body as exemplified above.
The spacer 20y located outside the first spacer 20x (hereinafter also referred to as “second spacer”) and the outermost spacer 20z (hereinafter also referred to as “third spacer”) are backup spacers, In the present embodiment, the thickness is thinner than the first spacer 20x.

The unvulcanized rubber molded article 1 is usually difficult to completely prevent the rubber and the vulcanizing agent from reacting during the production process, and it is difficult to obtain a completely raw rubber state.
Further, it is usually difficult for the unvulcanized rubber molded body 1 to have the same degree of reaction among production lots.
Further, when the unvulcanized rubber molded body 1 contains a filler such as carbon black, the hardness may slightly vary depending on the lot of the filler.
For this reason, the unvulcanized rubber molded body 1 may have a slightly different compression elastic modulus depending on the production lot.
Then, in the vulcanization process using only the first spacer 20x, the degree of compression of the unvulcanized rubber molded body 1 by the upper heating platen 50a varies depending on the production lot even if the press pressure is the same, and the resulting vulcanized rubber molding is obtained. May have different body thickness.
Therefore, when only the first spacer 20x is used in the vulcanization process, a vulcanized rubber molding is produced by controlling only the press pressure unless a sensor or the like for obtaining information on the vertical position of the upper heating platen 50a is used. It may be difficult to stabilize the quality of the body.

On the other hand, when backup spacers 20y and 20z having a thickness smaller than that of the first spacer 20x are arranged outside the first spacer 20x as illustrated in FIG. 5, the use of a sensor for specifying the position of the hot platen is used. Can be omitted.
Explaining this point, the upper heating platen 50a, when starting the vulcanization process, when the unvulcanized rubber molded body 1 and the first spacer 20x are lowered while being compressed in the thickness direction, the backup spacer 20y. , 20z, the repulsive force from the backup spacers 20y, 20z is received.
Therefore, for example, if the lowering of the upper heating platen 50a is stopped when the repulsive force from the backup spacers 20y, 20z is detected, a difference in thickness for each lot occurs in the vulcanized rubber molded body to be produced. This can be prevented.
In order to make the second spacer 20y and the third spacer 20z exhibit such a function, it is preferable that the compression elastic modulus in the thickness direction is higher than the compression elastic modulus of the first spacer 20x.
In addition, it is preferable that either one or both of the second spacer 20y and the third spacer 20z do not have stretchability in the thickness direction and the width direction like a metal spacer.
It should be noted that the above-mentioned obtained by providing a spacer that is less stretchable in the thickness direction than the spacer 20x and thinner than the spacer 20x outside the spacer 20x that has stretchability in the thickness direction and the width direction. Such advantages can be obtained even when there is only one backup spacer.
The merit can be obtained not only when the vulcanization process is performed by a hot press machine, but also in a rotocure continuous vulcanization molding machine described later.

It is preferable that the vulcanization step using the hot press machine as described above is performed while cooling a part of the upstream side without bringing the entire hot platen of the hot press machine into a heated state.
That is, when the entire surface of the hot platen is heated, heat is transmitted from the hot platen side to the unvulcanized rubber molded body located immediately before the hot platen, and in this state, substantially no pressure is applied. There is a risk of causing vulcanization.

Accordingly, with reference to FIG. 1, the upstream region from the position moved by the distance D2 from the upstream edge of the surface of the heat platen 50a, 50b to the downstream is used as a cooling region. It is preferable to set the temperature of the board surface lower than that in the heating region.
More preferably, it is desirable that the cooling region is maintained at a temperature not higher than a normal temperature level (for example, 50 ° C. or lower) during the vulcanization process so that only pressure is applied.

After the vulcanization process is completed, the transfer process is performed by removing the unvulcanized rubber by a length (D3) obtained by subtracting the length D2 of the cooling region from the length D1 of the platen surface of the hot plates 50a and 50b. It is preferable to carry out so as to be the moving distance of the molded body 1.
At this time, in the cooling region, since the unvulcanized rubber molded body is pressed in the thickness direction, it is compared with an unvulcanized rubber molded body that has not yet been introduced into the hot press machine 5 on the upstream side. The thickness is thin and slightly wider.
In the vulcanization process performed by the hot press provided with the cooling region as described above, the wide portion and the non-vulcanized rubber molded body are simultaneously pressed by the hot platen in the next hot press. The
Therefore, in the said hot press, the wide part and the part which is not so differ in the behavior which spreads in the width direction.
However, the spacer according to the present embodiment can be expanded and contracted in the width direction, has excellent followability to the deformation behavior of the unvulcanized rubber molded body, and can make the lateral pressure in the length direction of the unvulcanized rubber molded body uniform. .
Thereby, in this embodiment, even if it provides a cooling area | region and implements a vulcanization | cure process as mentioned above, the quality conveyor belt with which the shape of the both-sides edge part was prepared can be produced.

The spacers and the hot plates 50a and 50b are not necessarily in direct contact with the unvulcanized rubber molded body, and the vulcanization step is made smooth so that the transfer step can be carried out smoothly. You may implement in the state which arrange | positioned the inclusions, such as an outstanding sheet | seat and a mold release material, between the hot platen and the unvulcanized rubber molded object.

As the inclusion, a resin sheet is preferable, and a fiber-reinforced resin sheet is particularly preferable.
Among these, the inclusion is preferably a polytetrafluoroethylene resin sheet and more preferably a glass fiber reinforced polytetrafluoroethylene resin sheet in terms of excellent releasability and durability.
When such an inclusion is used, if a metal spacer is used as the backup spacer, the inclusion may be damaged by contact with the backup spacer, and the useful life of the inclusion is shortened. There is a risk of causing.
Therefore, in the case of using inclusions, it is preferable that the backup spacer is made of a polymer on both the upper and lower surfaces serving as a contact surface with the inclusions.

In addition, the conveyor belt obtained by making it above can be made into endless form by conventionally well-known joining methods, such as a lap | wrap system, a finger system, and a butt | matching system.
In this embodiment, the product appearance can be improved in such a product, and the work of deburring or repairing the indentation due to the removed burr can be omitted.
In addition, not only when the final form of the vulcanized rubber molded body is a conveyor belt, but also when the rubber dam, the rubber floor material, the rubber crawler, etc. are the same, the merit is remarkably exhibited. .

The spacer of this embodiment can be formed of a general rubber elastic body, such as ethylene-α-olefin elastomer (EPM, EPDM), butyl rubber (IIR), chloroprene rubber (CR), natural rubber (NR), etc. It is formed by a rubber elastic body made of a rubber composition in which a reinforcing agent (filler) such as carbon black or silica, an anti-aging agent, a plasticizer, a processing aid, a crosslinking aid, a flame retardant, etc. is appropriately blended with a base rubber. be able to.
The rubber elastic body constituting the spacer is preferably made of an ethylene-α-olefin elastomer such as EPDM as the base rubber from the viewpoint of excellent compression durability and heat resistance.
From the viewpoint of excellent heat aging resistance and releasability from the unvulcanized rubber molding, the rubber elastic body constituting the spacer is preferably butyl rubber as the base rubber.
Furthermore, the rubber elastic body constituting the spacer is measured using a type A durometer according to the measuring method based on the test method of JIS K6253, considering the follow-up to the deformation of the unvulcanized rubber molded body during pressurization and heating. The rubber hardness at the standard test temperature to be measured (23 ± 2 ° C.) is preferably 75 to 95 °.

The spacer is not limited to the one formed entirely of a rubber elastic body, and only a part of the spacer may be formed of a rubber elastic body.
The spacer according to the present embodiment can be variously selected as long as it exhibits a property of being compressed and deformed at least by stress applied in the thickness direction, and when the stress is removed, the thickness and width are substantially restored to the state before compression. The thing of the aspect of can be utilized.
6A shows a spacer made of only a rubber elastic body, and FIGS. 6B to 6H show other modes.
Hereinafter, some preferred embodiments of the spacer will be described with reference to FIG.
FIG. 6B shows a structure in which the canvas CB is laminated on both upper and lower surfaces of the rubber elastic body RB, and FIG. 6C shows a structure in which the canvas CB is embedded in the central portion in the thickness direction of the rubber elastic body RB. is there.
Further, FIG. 6 (d) shows that the canvas CB is embedded in the center portion in the thickness direction of the rubber elastic body RB and the canvas CB is laminated on both upper and lower surfaces. FIG. 6 (e) shows a square bar-like rubber elasticity. The circumference (all circumferences) of the body RB is covered with the canvas CB.
FIG. 6F shows the core CD embedded in the central portion of the spacer in the thickness direction.
In the embodiments shown in FIGS. 6B to 6F, the tensile strength is exerted on the spacer by the tensile body such as the canvas CB and the core CD, and the stretchability in the length direction of the spacer is regulated. .
In other words, the spacers in these aspects are restricted in stretchability in the length direction compared to stretchability in the thickness direction and width direction, and have high strength in the length direction.

FIG. 6G shows a core material CR that is slightly thinner than the spacer, and the core material CR is surrounded by a rubber elastic body RB.
The core material CR can be made of a material having higher hardness (compression elastic modulus) than the rubber elastic body RB such as resin, wood, metal, etc., and the rubber elastic body RB constituting the outer surface of the spacer. It is also possible to use a softer rubber elastic body or gel.
Furthermore, if necessary, the spacer may be of a type as shown in FIG. 6 (h) in which metal thin plates MB are laminated on the upper and lower surfaces of the rubber elastic body RB.

In addition, the spacer does not necessarily have to have a rectangular or square cross-sectional shape, and in addition to a right-angle trapezoid, a parallelogram, etc., a spacer having a polygonal shape that is a pentagon or more, a circle, an ellipse, or an indefinite shape is also available. This can be adopted as long as the effects of the present invention are not significantly impaired.

Moreover, the manufacturing method of the vulcanized rubber molded body (conveyor belt) of the present embodiment is not necessarily carried out only by a hot press machine, but a rotocure continuous vulcanization molding machine as shown in FIGS. Can also be implemented.

7 and 8, the rotocure continuous vulcanization molding machine is, for example, a metal cylinder rotatable around a rotation axis as a pressurizing member for pressurizing the unvulcanized rubber molded body 1 ′ in the thickness direction. A heating drum 100 made of a body and an endless steel band 200 are provided.
The endless steel band 200 is slightly narrower than the length of the heating drum 100 in the rotation axis direction, and the unvulcanized rubber molded body 1 ′ is sandwiched between the heating drum 100 and the heat of the heating drum 100. Thus, while the unvulcanized rubber molded body 1 ′ is vulcanized, it is provided in a rotocure continuous vulcanization molding machine so as to continue to pressurize it in the thickness direction.
More specifically, around the heating drum 100, four rolls 300, 400, 500, 600 having a diameter smaller than that of the heating drum 100 are arranged, and the endless steel band 200 includes four rolls 300. , 400, 500, 600 are provided in the rotocure continuous vulcanization molding machine in such a manner that the inner surface is brought into contact with the outer peripheral surface.

On the other hand, the heating drum 100 located substantially inside the quadrilateral connecting the rotation axes of the four rolls 300, 400, 500, 600 has its outer peripheral surface abutted against the outer surface of the endless steel band 200. Touching.
The endless steel band 200 is wound around two or less adjacent rolls 300 and 400 out of the four rolls 300, 400, 500, and 600, only about a quarter or less. On the other hand, the remaining two rolls 500 and 600 are wound around a half or more, and are wound around the heating drum 100 between the two rolls 500 and 600 wound around the half or more. Yes.
The endless steel band 200 is wound over an area of about 3/4 of the outer peripheral surface of the heating drum 100.

Of the rolls, three rolls 400, 500, and 600 are arranged in the immediate vicinity of the heating roll 100 to press the endless steel band 200 directly toward the heating drum 100, and the remaining one roll The roll 300 is disposed at a position away from the heating roll 100 so as to apply tension to the endless steel band 200.
That is, the roll 300 is provided in a rotocure continuous vulcanization molding machine to adjust the tension by adjusting the distance to the heating drum 100 and adjust the pressure between the endless steel band 200 and the heating drum 100 by the tension. It is what was done.

Also in such a rotocured continuous vulcanization molding machine, a spacer is wound around both ends of the heating drum 100 in the width direction, and a strip-shaped unvulcanized rubber molded product is supplied between the spacers. By adopting a material that can expand and contract in the thickness direction and the width direction of the unvulcanized rubber molded body as the spacer when vulcanizing the unvulcanized rubber molded body in order along the length direction according to 100, It is possible to prevent burrs from occurring in the vulcanized portion 10b ′.

About the said spacer, it can be made into an endless thing whose circumference is longer than the outer circumference of the heating drum 100, for example.
The endless spacer 20 ′ can be used by being wound around both ends in the length direction of the heating drum 100 as illustrated in FIG.
The endless spacer 20 ′ suppresses the occurrence of burrs and sponge defects in the vulcanized rubber molded body by applying a side pressure to the unvulcanized rubber molded body 1 ′ between the endless steel band 200 and the heating drum 100. obtain.
The endless spacer 20 ′ is given a repulsive force corresponding to the lateral pressure from the unvulcanized rubber molded body 1 ′ outward in the rotation axis direction of the heating drum 100.
The endless spacer 20 ′ may deteriorate its function when its winding position is shifted outward due to the repulsive force.
Therefore, the endless spacer 20 ′ preferably has a shape capable of generating a strong frictional force between the endless spacer 20 ′ and the heating drum 100 so as not to cause an unintended displacement, and has a width of a certain extent. It is preferable.
Specifically, the endless spacer 20 ′ preferably has a width of 100 mm or more.
When the total width of the unvulcanized rubber molded body 1 ′ and the two endless spacers 20 ′ is smaller than the width of the endless steel band 200, the endless steel band 200 is not The vulcanized rubber molded body 1 ′ is brought into contact with a strong pressure to generate a strong tension, while at least one of both end portions in the width direction is not sandwiched between the heating drum 100 and the center. The tension is extremely reduced compared to the portion.
The endless steel band 200 is likely to be distorted when there is an extreme difference in the way in which the force is applied in the width direction as described above, and there is a possibility that the service life may be shortened.
Accordingly, when the width of the unvulcanized rubber molded body 1 ′ is “Wa”, the width of each endless spacer 20 ′ is “Wb”, and the width of the endless steel band 200 is “Wc”, the following relationship (1 ) Is preferable.

(Wa + 2 × Wb) ≧ (0.9 × Wc) (1)

Regarding “Wa” to “Wc”, it is more preferable that the following relationship (2) is satisfied.

(Wa + 2 × Wb) ≧ (Wc) (2)

When a backup spacer is used in addition to the endless spacer 20 ′ that can be expanded and contracted in the thickness direction and the width direction, the total value of the widths of all the spacers and the unvulcanized rubber molded body 1 ′ is the endless steel. The width of the band 200 is preferably 0.9 times or more, and more preferably 1.0 times or more.
In addition, the merit demonstrated by using the backup spacer is as described in the embodiment using the hot press.

That is, in the method for producing a vulcanized rubber molded body according to the present embodiment, even when a rotocured continuous vulcanization molding machine is used, a high-quality vulcanized rubber molded body is produced by suppressing occurrence of appearance defects and labor. be able to.
Here, the detailed description will not be repeated any more, but the present invention is not limited to the above examples, and conventionally known events relating to the production of a vulcanized rubber molded article can be appropriately adopted. It is not limited.

1 Unvulcanized rubber molding 5 Heat press machine 20 Spacer

Claims (8)

1. A pressure member for pressing the unvulcanized rubber molded body in the thickness direction is disposed on one side and the other side of the belt-shaped unvulcanized rubber molded body, and the unvulcanized rubber molded body is The unvulcanized rubber molded body is vulcanized by heating while being pressurized with a pressure member, and the vulcanization is carried out sequentially along the length direction of the unvulcanized rubber molded body to form a belt-like vulcanized A method for producing a vulcanized rubber molded body for producing a rubber molded body,
   Spacers for restricting deformation in the width direction and thickness direction of the unvulcanized rubber molded body by the pressurization are disposed on both outer sides in the width direction of the unvulcanized rubber molded body, and the vulcanization is performed, and A method for producing a vulcanized rubber molded body, characterized in that a spacer that can expand and contract at least in the pressurizing direction and in the width direction of the unvulcanized rubber molded body is used as a spacer.
2. The pressurizing member is a pair of hot plates provided in a hot press machine,
   The spacer is a rectangular bar-like body having a length equal to or longer than that of the heating plate and partially or entirely formed by a rubber elastic body, and the thickness direction and width are determined by elastic deformation of the rubber elastic body. The method for producing a vulcanized rubber molded body according to claim 1, wherein the vulcanized rubber molded body is a rod-shaped body that can expand and contract in a direction.
3. 3. The method for producing a vulcanized rubber molded body according to claim 2, wherein the spacer is the rod-shaped body which is entirely constituted by the rubber elastic body and is also extendable in the length direction.
4. 3. The vulcanization according to claim 2, wherein the spacer includes a tensile body including at least one of a core wire and a canvas and the rubber elastic body, and the tensile body is a rod-shaped body arranged along a length direction. A method for producing a rubber molded body.
5. The manufacturing method of the vulcanized rubber molding of any one of Claims 1 thru | or 4 which manufactures the vulcanized rubber molding used for a conveyor belt, a rubber dam, a rubber flooring, or a rubber crawler.
6. When the band-shaped unvulcanized rubber molded body is heated while being pressed in the thickness direction, the unvulcanized rubber molded body is vulcanized to produce a band-shaped vulcanized rubber molded body. In order to restrict deformation of the vulcanized rubber molded body in the width direction and the thickness direction, the unvulcanized rubber molded body is disposed on both outer sides in the width direction and is extendable in the thickness direction and the width direction. Characteristic spacer.
7. The spacer according to claim 6, wherein the spacer is a square bar-like body made entirely of a rubber elastic body, and is a rod-like body that can expand and contract in the thickness direction, the length direction, and the width direction.
8. 7. A square bar-like rod-shaped body constituted by a tensile body made of at least one of a core wire and a canvas and a rubber elastic body, and the tensile body is a rod-shaped body arranged along a length direction. The spacer described.
   
   

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