JP2001239528A - Method for vulcanizing rubber using superheated steam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for vulcanizing using superheated steam which can reduce the vulcanization time of rubber and vulcanize it uniformly. SOLUTION: Superheated steam is used as a heating medium for the vulcanization of rubber, and the superheated steam is contacted with the rubber at a wind velocity so that the vertical component of a relative velocity of the steam to the rubber is at least 1.0 m/s. In this way, since water droplets generated by the condensation of the steam are scattered uniformly, a period in which the temperature increase of the rubber is retained at 100 deg.C is curtailed remarkably so that the rubber can be vulcanized in a short time. Besides, since the water droplets are scattered uniformly, the rubber can be vulcanized uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for vulcanizing rubber, and more particularly to a method for vulcanizing rubber using superheated steam as a heat medium for vulcanization.

[0002]

2. Description of the Related Art Vulcanization is an operation in which a vulcanizing agent is mixed with raw rubber to form a crosslinked structure between rubber molecules in order to increase the elasticity of the rubber. Vulcanization is common. When using steam, it is necessary to pressurize the steam in order to make the steam 100 ° C. or higher. Therefore, a method of vulcanizing rubber using superheated steam obtained by heating steam without applying pressure as a heat source has been proposed. As a method for obtaining superheated steam, there are a method using a burner and a heat exchanger and a method using an electric heater.

[0003]

However, in the method of obtaining superheated steam using a burner and a heat exchanger, a large amount of superheated steam can be obtained, but the temperature control of the superheated steam is difficult and the temperature of the superheated steam is stabilized. It will take some time. On the other hand, in a method of obtaining superheated steam by an electric heater, a superheated steam having a stable temperature can be obtained, but a large amount of superheated steam cannot be obtained. For this reason, when vulcanizing the rubber using the superheated steam obtained by any of the above methods, there is a problem that the vulcanization time becomes long or the vulcanization is uneven. For the above reasons, a method for vulcanizing rubber using superheated steam as a heat source has been conventionally proposed,
Not practical.

[0004] The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of vulcanizing rubber using superheated steam, which can shorten the time required for vulcanizing rubber and vulcanize uniformly. It is to provide.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the inventors have obtained the following findings. Normally, the temperature of the rubber before vulcanization is 100 ° C. or lower, and when the rubber is exposed to superheated steam, the superheated steam condenses and water droplets are generated on the surface of the rubber. The water droplets generated on the surface of the rubber are evaporated by the heat of the superheated steam in the vulcanizing furnace, and the latent heat greatly deprives the energy of the superheated steam. Therefore, although the specific heat of the superheated steam is larger than that of the hot air, the temperature rise of the rubber stagnates at 100 ° C., and it takes a certain time until the temperature rises to 100 ° C. or more. It has been found that the warming time is slow and the vulcanization time of the rubber is long. In addition, it has been found that since the temperature of rubber rises slowly in a portion where water droplets are present, vulcanization is unevenly performed in a portion where water droplets exist and a portion where no water droplets exist. Then, the inventor completed the following invention based on the said knowledge.

The invention according to claim 1 uses superheated steam as a heat medium for vulcanization when vulcanizing rubber, and the vertical component of the relative speed of the superheated steam to the rubber is at least 1.0 m / s or more. A method of vulcanizing rubber using superheated steam in which the superheated steam acts on the rubber at a wind speed of

When superheated steam is applied to the rubber at a wind speed at which the vertical component of the relative velocity with respect to the rubber is at least 1.0 m / s, water droplets generated by the condensation of the superheated steam are blown off or evenly dispersed. In this way, since the water droplets generated by the condensation of the superheated steam are blown off or evenly dispersed, the state in which the water droplets generated on the rubber surface remain on the rubber surface until the heat of the superheated steam evaporates is eliminated. Can be. For this reason, the time during which the temperature rise of the rubber stays at 100 ° C. can be greatly reduced, so that the rate of temperature rise of the rubber can be increased and vulcanization can be performed in a short time.
In addition, because water droplets are blown away or evenly scattered,
Rubber can be uniformly vulcanized.

The vertical component of the relative speed of the superheated steam with respect to the rubber is preferably 2.0 to 10.0 m / s, and more preferably 4.0 to 10.0 m / s. Increasing the vertical component of the relative speed to rubber,
This is because water droplets generated by condensation of the superheated steam can be more effectively blown off or evenly dispersed. In particular, when the vertical component of the relative speed of the superheated steam with respect to the rubber is 4.0 m / s or more, the temperature of the rubber rises without stagnation at 100 ° C. However, the upper limit of the vertical component of the relative speed of the superheated steam with respect to the rubber is a wind speed at which the rubber is not blown off, and varies depending on the shape and specific gravity of the rubber.

[0009] The rubber is not limited to the case where it is installed horizontally in a vulcanizing furnace, and may be vulcanized by being installed diagonally or vertically. In particular, when vulcanizing a rubber having a large cross-sectional shape, water droplets can be scattered more efficiently because the water droplets flow from the surface of the rubber by their own weight.

According to a second aspect of the present invention, superheated steam is used as a heat medium for vulcanization when vulcanizing rubber, and the preheated rubber is heated to 100 ° C. or higher before vulcanization. It is a method of vulcanizing rubber.

As described above, the rubber before vulcanization is previously heated to 100 ° C.
According to the above, even when the rubber is exposed to superheated steam during vulcanization, the superheated steam does not condense and no water droplets are generated on the rubber surface. Therefore, the temperature rise of rubber is 100 ° C
Rise without stagnation. As a result, the rate of temperature rise of the rubber can be increased, and vulcanization can be performed in a short time. Also,
Since no water droplets are generated, the rubber can be uniformly vulcanized.

According to a third aspect of the present invention, in the method for vulcanizing rubber using superheated steam, the superheated steam is superheated steam obtained by heating steam by electromagnetic induction heating. It is. Superheated steam superheated by electromagnetic induction heating is superheated steam obtained by bringing steam into contact with a heating element that has generated heat by electromagnetic induction heating, and steam is not directly superheated.

According to a fourth aspect of the present invention, the superheated steam heats the laminated body having a passage formed by laminating a plurality of plates, and then superheats the steam by flowing the steam through the passage of the heated laminated body. A method for vulcanizing rubber using superheated steam according to claim 3, which is obtained by the above method. When steam is superheated in a laminate in which a magnetic field and an electric field due to electromagnetic induction act at a high density, superheated steam having a stable temperature can be obtained in a shorter time than in the case of simple electromagnetic induction heating.

The invention according to claim 5 includes the step of spraying the superheated steam on the whole or a part of the rubber, wherein the rubber is heated using the superheated steam according to any one of claims 1 to 4. It is a sulfurization method. By spraying superheated steam from a nozzle etc. onto the rubber surface like a shower,
Oil on the surface of rubber and reaction products of various vulcanization accelerators can be effectively volatilized. In addition, by directly heating the sponge rubber by spraying superheated steam from a nozzle or the like onto the surface of the sponge rubber, it becomes possible to control the curl phenomenon generated during continuous extrusion vulcanization of the sponge rubber. .

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described. Superheated steam is used as a heat medium for vulcanization when vulcanizing rubber, and the superheated steam is blown into a vulcanization furnace. This superheated steam is such that the vertical component of the relative velocity to the rubber in the vulcanizing furnace has a wind speed of at least 1.0 m / s or more.
It is blown.

When superheated steam hits the surface of the rubber, the surface of the rubber is initially 100 ° C. or less at the time of vulcanization. Therefore, the superheated steam is deprived of heat and condenses, forming water droplets on the surface of the rubber.
However, the superheated steam acts on the rubber at a wind speed at which the vertical component of the relative velocity to the rubber is at least 1.0 m / s, so even if the water droplets generated by the condensation of the superheated steam are blown off immediately, Scatter evenly. For this reason, it is possible to eliminate a state in which water droplets generated on the rubber surface continue to exist on the rubber surface until the water droplets evaporate due to the heat of the superheated steam, and take away the energy of the superheated steam due to the latent heat when the water droplets evaporate. Can be prevented.

As described above, the vulcanization is terminated when a predetermined time has elapsed while applying superheated steam to the surface of the rubber.

The vertical component of the relative speed of the superheated steam with respect to the rubber is preferably 2.0 to 10.0 m / s, and more preferably 4.0 to 10.0 m / s. Increasing the vertical component of the relative speed to rubber,
This is because water droplets generated by condensation of the superheated steam can be more effectively blown off or evenly dispersed. However, the upper limit of the vertical component of the relative speed of the superheated steam with respect to the rubber is a wind speed at which the rubber is not blown off, and varies depending on the shape and specific gravity of the rubber.

The rubber is not limited to the case where the rubber is installed horizontally in the vulcanizing furnace, but may be installed diagonally or vertically and vulcanized. In particular, when vulcanizing a rubber having a large cross-sectional shape, water droplets can be scattered more efficiently because the water droplets flow from the surface of the rubber by their own weight.

Next, an example of a vulcanizing apparatus that can be used in the vulcanizing method using superheated steam according to the present embodiment will be described with reference to FIG. As shown in FIG. 1, the vulcanizing apparatus 1 includes an extruder 2, a vulcanizing furnace 3, a take-off machine 4, a circulation fan 5, a superheated steam generator 6, an exhaust fan 7, and a harmful substance removing machine. 8
And

The extruder 2 is connected to a vulcanizing furnace 3,
The raw rubber is molded while being extruded, and the raw rubber is supplied to the vulcanizing furnace 3. The vulcanizing furnace 3 raises the temperature of the molded raw rubber to a certain temperature and keeps the state for a predetermined period. In the vulcanizing furnace 3, superheated steam is used as a heat medium for raising the temperature of the raw rubber.
For this reason, the inside of the vulcanizing furnace 3 is in a state of being filled with only superheated steam, and is in a state of not containing air, nitrogen gas, or the like. The take-off machine 4 is connected to the downstream side of the vulcanizing furnace 3 and takes the vulcanized rubber from the vulcanizing furnace 3.

The circulation fan 5 is connected to the vulcanizing furnace 3 in a loop, and sends superheated steam as a heat medium to the vulcanizing furnace 3. The circulation fan 5 blows air in the vulcanizing furnace 3 so that the vertical component of the relative speed of the superheated steam to the rubber is at least 1.0 m / s or more. The exhaust fan 7 is connected to the downstream side of the vulcanizing furnace 3, exhausts the superheated steam in the vulcanizing furnace 3, and sends it to the harmful substance removing machine 8. The harmful substance remover 8 removes harmful substances from exhaust gas sent from the exhaust fan 7.

The superheated steam generator 6 is connected outside the loop of the circulation fan 5 and the vulcanizing furnace 3 so that the superheated steam discharged from the vulcanizing furnace 3 does not pass through the superheated steam generating section 6. It is connected. For this reason, dirt, dust, and the like contained in the discharged superheated steam are less likely to enter the superheated steam generator 6.

The superheated steam generating section 6 includes the electromagnetic induction heating section 1
An electromagnetic induction heating device 10 (see FIG. 2) including the first and second high-frequency power supplies 19 and a water supply source (not shown) are provided. Water is supplied from the water supply source to the electromagnetic induction heating unit 11,
The electromagnetic induction heats water to steam, and the electromagnetic induction heating unit 12 generates superheated steam from steam to superheated steam in two stages.

As shown in FIG. 2, the electromagnetic induction heating unit 11,
12 includes heating elements 13 and 14, coils 15 and 16, and nonmagnetic pipes 17 and 18, and coils 15 and 16.
Are connected to a high frequency power supply 19.

The heating elements 13 and 14 are accommodated in non-magnetic pipes 17 and 18 formed in a cylindrical shape, and when power is supplied to the coils 15 and 16 from the high frequency power supply 19,
An eddy current is generated to generate heat.

The pipes 17 and 18 accommodate the heating elements 13 and 14 and form a fluid passage. This pipe 1
Reference numerals 7 and 18 denote ceramic pipes made of a non-magnetic material and having excellent heat resistance, for example, formed of silicon nitride.

The coils 15 and 16 are wound around the pipes 17 and 18 to transmit magnetic flux to the heating element. The high-frequency power supply 19 is a high-frequency inverter, and is connected to the coil 15 and a temperature sensor in the vulcanizing furnace 3 and a temperature sensor in the circulation system, and supplies electric power to the coils 15 and 16 according to the temperature detected by the temperature sensor. Supply,
The heating element is adapted to generate heat.

As described above, the electromagnetic induction heating device 10
First, the electromagnetic induction heating unit 11 heats water to steam, and then the electromagnetic induction heating unit 12 heats the steam to superheated steam at a predetermined temperature. Electromagnetic induction heating device 1
0 can easily control the temperature of the superheated steam,
Further, since the size can be reduced, the size of the superheated steam generator 6 can be reduced. At the stage of heating from water to steam, heating from water to steam may be performed using a normal boiler or an electric heater without using electromagnetic induction heating.

Next, a vulcanizing method using the above-described vulcanizing apparatus 1 will be described with reference to FIG. The raw rubber is molded while being extruded from the extruder 2, and the molded raw rubber is sent to the vulcanizing furnace 3. When the raw rubber is sent to the vulcanizing furnace 3, in the superheated steam generating section 3, water is supplied from a water supply source (not shown) to the electromagnetic induction heating section 11, and heated to steam. And
This steam is superheated by the electromagnetic induction heating unit 12 to superheated steam at a predetermined temperature of 200 to 500 ° C.

When the superheated steam is heated to a predetermined temperature of 200 ° C. or higher, the high-frequency power supply 19 controls the temperature of the superheated steam in the vulcanizing furnace 3 detected by the temperature sensor in the vulcanizing furnace 3 and the temperature in the circulation system. The electric power is supplied to the coils 15 and 16 in accordance with the temperature of the superheated steam in the circulation system detected by the temperature sensor of (1) to cause the heating elements 13 and 14 to generate heat. The heating elements 13 and 14 generate eddy currents to generate heat, and superheat the steam to superheated steam at a predetermined temperature of 200 ° C. or higher. According to the electromagnetic induction heating device 10, the temperature control of the superheated steam is easy.

The generated superheated steam is blown through the circulation fan 5 in the vulcanizing furnace 3 so that the vertical component of the relative speed with respect to the rubber is at least 1.0 m / s or more.

When superheated steam having a vertical component of 1.0 m / s or more hits the surface of the rubber, the surface of the rubber is initially vulcanized.
Since the temperature is not higher than 100 ° C., the superheated steam is deprived of heat and condensed to form water droplets on the rubber surface. However, superheated steam has a vertical component of relative velocity to rubber of at least 1.
Since it acts on the rubber at a wind speed of 0 m / s or more, even if superheated water vapor is condensed, the generated water droplets are immediately blown off or evenly dispersed. For this reason, it is possible to eliminate a state in which water droplets generated on the rubber surface continue to exist on the rubber surface until the water droplets evaporate due to the heat of the superheated steam, and take away the energy of the superheated steam due to the latent heat when the water droplets evaporate. Can be prevented.

A part of the superheated steam in the vulcanizing furnace 3 is exhausted by an exhaust fan 7 and is discharged as an exhaust gas.
Sent to The exhaust gas is detoxified by the harmful substance removing machine 8 and discharged. On the other hand, the other superheated steam merges with the superheated steam from the superheated steam generator 6 and is sent again into the vulcanizing furnace 3 by the circulation fan 5. The temperature in the circulatory system is
The temperature in the circulation system is controlled by adjusting the temperature of the superheated steam generated from the superheated steam generator 6. As described above, the rubber is vulcanized by a series of steps, and after a predetermined time has elapsed, the rubber in the vulcanizing furnace 3 is taken from the take-up machine 4.

The temperature in the circulating system can be controlled by adjusting the temperature of superheated steam as a heat medium,
There are two methods of adjusting the blowing amount of superheated steam as a heat medium. If the temperature in the circulating system is controlled by adjusting the blowing rate of superheated steam, air can easily enter the vulcanizing furnace when a load occurs in the circulating system, such as when the temperature of rubber rises or when rubber is replaced. Therefore, it is not suitable for peroxide crosslinking which cures in a state where oxygen is blocked. On the other hand, if the temperature in the circulation system is controlled by adjusting the temperature of the superheated steam as the heat medium, the inside of the vulcanizing furnace 3 can be kept under an atmosphere in which oxygen is cut off. Suitable for peroxide crosslinking which cures in a blocked state.

Next, a case where a laminated body is used as the heating elements 13 and 14 will be described. For example, as shown in FIG. 3, a heating element 30 in which a first metal plate 31 and a flat metal plate 32 bent in a zigzag mountain shape are alternately laminated to form a cylindrical laminated body as a whole is illustrated. The case where the heating elements 13 and 14 shown in FIG. 2 are used as examples will be described. As a material of the metal plates 31 and 32, a martensitic stainless steel such as SUS447J1 is used.

As shown in FIG. 4, the heating element 30 is arranged such that the peak (or valley) 33 of the first metal plate 31 is inclined by an angle α with respect to the central axis 34, and the second metal plate 32 is The peaks (or valleys) 33 of the first metal plates 31 adjacent to each other are arranged so as to intersect. Then, at the intersection of the peaks (or valleys) 33 of the adjacent first metal plates 31, the first metal plate 31 and the second metal plate 32 are welded by spot welding and joined to be electrically conductive.

Thus, between the outermost first metal plate 31 and the second metal plate 32, the first small flow path 35 inclined by the angle α is provided.
Is formed, and a second small flow path 36 inclined by an angle -α is formed between the next second metal plate 32 and the first metal plate 31,
The first small flow path 35 and the second small flow path 36 intersect at an angle of 2 × α. In addition, the first metal plate 31 and the second metal plate 32
A hole 37 is formed as a third small channel for generating a turbulent flow of water or steam. Further, the surfaces of the first metal plate 31 and the second metal plate 32 are not smooth, and are provided with minute unevenness 38 by matte finish or embossing. The unevenness 38 is negligibly small compared to the height of the peak (or valley) 33 (see FIG. 4).

The heating element 30 is inserted into the pipes 17 and 18, and a high-frequency current is applied to the coils 15 and 16 so that the heating element 3
When a high-frequency magnetic field is applied to 0, an eddy current is generated in the entire first metal plate 31 and the second metal plate 32 which are obliquely arranged so as to cross the magnetic field lines, and the entire heating element 30 uniformly generates heat. The heating element 30 is formed of SU forming each of the metal plates 31 and 32.
It is possible to generate heat up to a temperature (about 600 ° C.) determined by magnetic characteristics (Curie point) such as S447J1.

As shown in FIG. 4, water or steam is diffused between the peripheral portion and the central portion in the first small flow passage 35 and the second small flow passage 36 which intersect in the heating element 30. Due to the presence of the hole 37 serving as a small channel, the first small channel 35 and the second small channel 36
Diffusion in the thickness direction between them is also performed. Therefore, each small channel 3
5, 36, 37 cause macro diffusion, emission and volatilization of water or water vapor throughout the heating element 8, and
Microscopic diffusion, dissipation,
Volatilization also occurs. As a result, the water or steam passing through the heating element 30 becomes a substantially uniform flow, and a uniform opportunity of contact between the first metal plate 31 and the second metal plate 32 and the water or steam is given, and uniform heating is performed. Secured.

As described above, when steam is overheated by the electromagnetic induction heating device using the laminate, the magnetic field and electric field due to the electromagnetic induction act on the steam at high density, and the resulting superheated steam may be activated. When such superheated steam acts on the surface of the rubber, water droplets on the surface of the rubber can be efficiently dispersed. At the stage of heating from water to steam, heating from water to steam may be performed using a normal boiler or an electric heater without using electromagnetic induction heating.

The vulcanization method using superheated steam is as follows:
The vulcanization method using the superheated steam according to the present embodiment is only one example of the vulcanization method using the superheated steam according to the present embodiment, and is not limited to the above method.

Next, another example of a vulcanizing apparatus that can be used in the vulcanizing method using superheated steam according to the present embodiment will be described with reference to FIG. The difference from the vulcanizing apparatus 1 of FIG. 1 is that the electromagnetic induction heating unit 12 is connected to the downstream side of the circulation fan 5 (between the circulation fan 5 and the vulcanizing furnace 3). The vulcanizing apparatus 41 shown in FIG. 5 can easily make the amount of superheated steam blow constant even when the temperature condition of the superheated steam in the vulcanizing furnace 3 is changed, as compared with the vulcanizing apparatus 1 shown in FIG. The structure is easy to balance the wind pressure in the sulfurizing furnace 3. For this reason, it is possible to reduce the entry of air into the vulcanizing furnace 3 when the temperature in the vulcanizing furnace 3 is changed. For other points,
Since it is the same as the vulcanizing apparatus 1 shown in FIG. 1, the description is omitted.

[0044]

Next, a method for vulcanizing rubber using superheated steam according to the present invention was performed under the following conditions.

Example 1 A vulcanizing apparatus 1 shown in FIG. 1 was used. The raw rubber components to be vulcanized are as shown in Table 1. 100 g of the raw rubber of the components shown in Table 1 were vulcanized. The temperature of the superheated steam supplied into the vulcanizing furnace was 240 ° C. Superheated steam was allowed to act on the raw rubber at a wind speed at which the vertical component of the relative velocity to the rubber was 4.0 m / s.

[0046]

[Table 1]

<Example 2> Superheated steam was allowed to act on the raw rubber at a wind speed at which the vertical component of the relative speed with respect to the rubber was 1.7 m / s. Other conditions are the same as in the first embodiment.

<Comparative Example 1> Superheated steam was allowed to act on raw rubber at a wind speed at which the vertical component of the relative speed with respect to the rubber was 0.7 m / s. Other conditions are the same as those of the first and second embodiments.

<Comparative Example 2> In place of superheated steam, heated air was used. Other conditions are the same as in Comparative Example 1.

FIG. 6 is a graph showing the temperature rise time of the rubbers of Example 1, Example 2, and Comparative Example 1. At the beginning of the vulcanization, the temperature of the raw rubber is 100 ° C. or less, so that the superheated steam is deprived of heat on the surface of the raw rubber and condensed to form water droplets on the surface of the raw rubber. In the case of Comparative Example 1, the temperature rise of the raw rubber temporarily stops at 100 ° C. due to the latent heat when the water droplet evaporates, and it takes T ₂ hours until the temperature of the raw rubber rises to 100 ° C. or higher. On the other hand, in the case of Example 2, the superheated steam acts on the raw rubber at a wind speed at which the vertical component of the relative velocity with respect to the raw rubber is 1.7 m / s. Therefore, even if water droplets on the raw rubber surface are generated, they are immediately blown off. Or evenly scattered. For this reason, the temperature of the raw rubber is T ₂ until it rises to 100 ° C. or more.
Requires only time shorter than T ₁ hour. Further, in the case of Example 1, since the superheated steam acts on the raw rubber at a wind velocity at which the vertical component of the relative velocity to the raw rubber is 4.0 m / s, water droplets on the surface of the raw rubber are blown off more quickly than in the case of Example 2. Scatter evenly. For this reason, as shown by the solid line, the temperature of the raw rubber draws a smooth temperature rising curve with almost no stagnation.

As described above, when superheated steam is applied to the raw rubber at a wind speed at which the vertical component of the relative speed to the raw rubber is 1.0 m / s as in Examples 1 and 2,
The temperature rise time of the raw rubber is fast, and the vulcanization time can be shortened. In addition, since water droplets on the surface of the raw rubber are immediately blown off or evenly dispersed, unevenness in vulcanization can be eliminated, and the raw rubber can be uniformly vulcanized. Furthermore, as a result of comparing Example 1 with Example 2, when the vertical component of the relative speed of the superheated steam to the raw rubber is increased within a range in which the rubber does not blow off, the steam can further shorten the vulcanization time and uniformly. It has been demonstrated that it can be vulcanized.

Next, the properties of the rubber vulcanized in Example 2 and Comparative Example 2 will be described with reference to Table 2.

[0053]

[Table 2]

In Example 2 in which the rubber was vulcanized with superheated steam, the tensile strength of the rubber was 1.7 MPa and the elongation was 190%.
, The compression set is 20%, there is no contamination,
There is no cracking in weather resistance (UV fade meter). On the other hand, in Comparative Example 2 vulcanized with heated air, the tensile strength of the rubber was 1.5 MPa and the elongation was
It is 180%, the compression set is 47%, there is contamination, and the weather resistance is cracked.

As described above, rubber vulcanized with superheated steam has better physical properties than rubber vulcanized with heated air.
The reason for this is that, in the case of the example, since the inside of the vulcanization furnace is saturated with superheated steam and vulcanization is performed in a state where oxygen is shut off, oxidation deterioration does not occur on the rubber surface as in Comparative Example 2. . Further, as described above, the vulcanization can be performed more uniformly than in the case of Comparative Example 2. For the above reasons, in the embodiment using superheated steam, it becomes possible to vulcanize rubber excellent in durability, weather resistance and compression set.

Next, a second embodiment according to the present invention will be described. Before vulcanization of the rubber, the rubber is preheated to 100 ° C. or higher.
Next, superheated steam is used as a heat medium for vulcanization when the rubber is vulcanized, and the superheated steam is blown into the vulcanization furnace.

When superheated steam hits the surface of the rubber, the surface of the rubber is already at 100 ° C. or more from the beginning of vulcanization.
The superheated steam does not condense on the surface of the rubber and does not become water droplets on the surface of the rubber. For this reason, the temperature rise of the rubber rises without stagnation at 100 ° C. As described above, when a predetermined time has elapsed while applying superheated steam to the surface of the rubber, vulcanization is terminated. In the second embodiment, since the rubber is heated to 100 ° C. or more before vulcanization to prevent water droplets from being generated on the surface of the rubber, the vulcanization method is performed as in the first embodiment. It is not necessary to apply superheated steam to the rubber at a wind speed at which the vertical component of the relative velocity to the rubber is at least 1.0 m / s.

Next, an example of a vulcanizing apparatus that can be used in the vulcanizing method using superheated steam according to the present embodiment will be described with reference to FIG. As shown in FIG. 7A, the vulcanizing device 51
Is provided with a shear head 2a in the extruder 2 of the vulcanizing apparatuses 1 and 41 of FIGS. 1 and 5. In addition, other parts
Since the configuration is the same as that of the vulcanizing apparatuses 1 and 41, the description is omitted.

The shear head 2a is mounted near the outlet of the extruder 2, and applies shear stress to the rubber extruded from the extruder to generate heat at 100 ° C. or higher.

Next, a vulcanizing method using the above-described vulcanizing apparatus 51 will be described with reference to FIG. The raw rubber is molded while being extruded from the extruder 2, and the rubber is heated to 100 ° C. or higher by applying shear stress to the rubber by the shear head 2 a. In this way, the rubber heated to 100 ° C. or more is sent to the vulcanizing furnace 3 and vulcanized by the action of superheated steam.

The surface of the rubber is already 100 ° C. from the beginning of vulcanization.
As described above, the superheated steam does not condense on the surface of the rubber and does not become water droplets on the surface of the rubber. For this reason, the temperature rise of the rubber rises without stagnation at 100 ° C. still,
Except that the temperature of the rubber is set to 100 ° C. or more before vulcanization, the method is the same as the vulcanization method using the vulcanizing apparatuses 1 and 41, and thus the description is omitted.

Note that the above vulcanization method using superheated steam previously heated to 100 ° C. or higher before vulcanization is merely an example of the vulcanization method according to the present embodiment, The vulcanization method using superheated steam previously heated to 100 ° C. or higher is not limited to the above method.

Next, another example of a vulcanizing apparatus that can be used in the vulcanizing method using superheated steam according to the present embodiment is shown in FIG.
It will be described based on. The difference between the vulcanizer 61 shown in FIG. 7B and the vulcanizer 51 shown in FIG. 7A is that a preliminary furnace 62 is provided instead of the shear head 2a. In other respects, the vulcanizing apparatus 1 shown in FIGS.
Since it is the same as 41, the description is omitted.

The pre-furnace 62 is provided between the extruder 2 and the vulcanizing furnace 3, and is used to reduce the rubber extruded from the extruder by 100%.
It is designed to be heated above ℃. As a method for heating the preliminary furnace 62, any of hot air, fluidized bed heating, hot steam, microwave heating, near infrared, far infrared, and induction heating may be used.

FIG. 1 shows another example of a vulcanizing apparatus that can be used in the vulcanizing method using superheated steam according to the present embodiment.
Alternatively, the extrusion conditions of the extruder 2 of the vulcanizing apparatuses 1 and 41 shown in FIG. 5 may be adjusted so that the extruded rubber has a temperature of 100 ° C. or higher. For example, the extrusion conditions are adjusted by adjusting the extrusion pressure or the structure of the barrel, screw, head, and the like of the extruder 2.

The vulcanizing apparatuses 1 and 41 according to the first embodiment
Alternatively, the vulcanizing furnace 3 of the vulcanizing apparatuses 51 and 61 according to the second embodiment
Inside, when superheated steam is sprayed from a nozzle or the like onto the rubber surface like a shower, oil on the rubber surface and reaction products of various vulcanization accelerators can be effectively volatilized. In addition, when vulcanizing sponge rubber, when superheated steam is sprayed from a nozzle or the like onto the surface of the sponge rubber to partially heat the sponge rubber, the curl phenomenon generated during continuous extrusion vulcanization of the sponge rubber is controlled. It becomes possible.

[0067]

According to the present invention, the superheated steam is applied to the rubber at a wind speed at which the vertical component of the relative velocity with respect to the rubber is at least 1.0 m / s or more. Blows out the water droplets generated by the condensation or evenly scatters. In this way, in order to blow off water droplets generated by condensation of superheated steam or to uniformly scatter the water droplets, there is no need for water droplets generated on the rubber surface to remain on the rubber surface until the heat of the superheated steam evaporates. be able to. Therefore, the temperature rise of the rubber is 10
Since the stagnation time at 0 ° C. can be greatly reduced, the rate of temperature rise of the rubber can be increased, and vulcanization can be performed in a short time. In addition, since the water droplets are blown off or evenly dispersed, the rubber can be vulcanized uniformly.

According to the second to fifth aspects of the present invention, since the temperature of the rubber before vulcanization is 100 ° C. or more in advance, the temperature of the rubber rises without stagnation at 100 ° C. As a result, the rate of raising the temperature of the rubber can be increased, and the effect of vulcanization in a short time is achieved. Further, since no water droplets are generated, there is an effect that the rubber can be uniformly vulcanized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an outline of a vulcanizing apparatus used in a method for vulcanizing rubber using superheated steam according to a first embodiment.

FIG. 2 is a diagram illustrating an electromagnetic induction heating device.

FIG. 3 is a diagram illustrating a laminate.

FIG. 4 is a diagram illustrating a laminate.

FIG. 5 is a diagram illustrating another example of a vulcanizing apparatus used in the method for vulcanizing rubber using superheated steam according to the first embodiment.

FIG. 6 is a graph showing the relationship between rubber temperature and vulcanization time.

FIG. 7 is a diagram illustrating a vulcanizing apparatus used in a method for vulcanizing rubber using superheated steam according to a second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 vulcanizing device 2 extruder 3 vulcanizing furnace 4 take-off device 5 circulation fan 6 superheated steam generator 7 exhaust fan 8 harmful substance removing machine 10 electromagnetic induction heating device 11, 12 electromagnetic induction heating unit

Continuing from the front page (72) Inventor Hiroyuki Konno 2-2-2, Mishino-cho, Nishi-ku, Hiroshima-shi, Hiroshima Nishikawa Rubber Industries Co., Ltd. (72) Inventor Taizo Kawamura 19-21 Misawa-cho, Ibaraki-shi, Osaka Se Co., Ltd. In-house (72) Inventor Yoshitaka Uchihori 19-21, Misawa-cho, Ibaraki-shi, Osaka F-term (reference) 4F203 AA45 AK01 AK11 AR06 AR08 DA11 DB01 DC04 DD01 DD10 DH06 DJ01 DL03 DM16

Claims (5)

[Claims] 1. A superheated steam is used as a heat medium for vulcanization when vulcanizing rubber, and the superheated steam is heated at a wind speed at which a vertical component of a relative speed of the superheated steam to the rubber is at least 1.0 m / s or more. A method of vulcanizing rubber using superheated steam in which steam acts on rubber. 2. Using superheated steam as a heat medium for vulcanization when vulcanizing the rubber, and before vulcanization, the rubber is preliminarily immersed in the rubber.
A method of vulcanizing rubber using superheated steam kept at 00 ° C or higher. 3. The method for vulcanizing rubber using superheated steam according to claim 1, wherein the superheated steam is superheated steam obtained by heating steam by electromagnetic induction heating. 4. The superheated steam is obtained by electromagnetically heating a laminated body in which a passage is formed by laminating a number of plates, and flowing steam to the heated passage of the laminated body to overheat. 3. A method for vulcanizing rubber using superheated steam according to 3. 5. The method for vulcanizing rubber using superheated steam according to claim 1, comprising a step of spraying the superheated steam on the whole or a part of the rubber.