JPH11207742A - Method and apparatus for producing reclaimed rubber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce reclaimed rubber of good quality efficiently. SOLUTION: Waste rubber chips 10 are sheared by a multi-screw extruder 30 and mixed with a reclaiming agent and subsequently plasticated while being kneaded in the extruder 30 to obtain reclaimed rubber 36. In this way, waste rubber can be plasticated sufficiently without requiring external heating, and reclaimed rubber of good quality can be obtained efficiently by a series of work.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing reclaimed rubber for plasticizing and regenerating waste rubber such as vulcanized waste tires.

[0002]

2. Description of the Related Art Waste rubber such as waste tires has been conventionally reused, and upon regeneration, the action of a vulcanizing agent contained in the waste tires is considered. It is necessary to make it possible to plastically process (plasticize)
The following regeneration methods (bread method and recreation method) are mainly employed. In the bread method, waste tires are steamed at a temperature of 200 ° C. or more to plasticize (desulfurize), and then the steamed rubber is ground by a roll machine to obtain a reclaimed rubber mass. However, since this method is a batch process and requires a long processing time of 4 to 5 hours for plasticization, there is a problem in that the efficiency is low and the regeneration cost is high. In the recruiter method, waste tires and the like are cut by a breaker or the like by 2 to 4 mm.
The rubber pieces are put into an extruder together with a regenerating agent, and they are kneaded while being heated to 200 ° C. or higher to regenerate them. Although this method is the only continuous desulfurization method, there is a problem that the quality is poor because rubber powder remains in the regenerated rubber or rubber molecules are cut too much. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method and an apparatus for manufacturing a recycled rubber capable of efficiently manufacturing a good quality recycled rubber.

[0003]

Means for Solving the Problems In order to solve the above-mentioned problems, among the present invention, a method for producing recycled rubber according to the first invention is a method for producing a vulcanized waste rubber chip by using a multi-screw extruder without applying external heating. It is characterized in that pulverized and plasticized while being pulverized by shearing force to obtain pulverized rubber particles. A method for producing a recycled rubber according to a second aspect of the invention is characterized in that the refining agent is mixed with the finely ground rubber particles of the first aspect of the invention and the mixture is kneaded and plasticized.

According to a third aspect of the present invention, there is provided an apparatus for producing recycled rubber, comprising a multi-shaft mixer in which a multi-shaft screw is disposed in a cylinder, wherein the cylinder is provided with an upstream shear region and a downstream kneading region. In the shearing area, a waste rubber charging section for charging the vulcanized waste rubber into the cylinder is provided, and near the boundary between the shearing area and the kneading area, a regenerating agent is charged into the cylinder. An agent charging section is provided, and a reclaimed rubber take-out section for taking out reclaimed rubber from the cylinder is provided downstream of the kneading area.

In the present invention, vulcanized waste rubber mainly composed of waste tires is to be recycled. The waste rubber may be composed of one kind of waste rubber or the like, or may be a mixture of a plurality of kinds of waste rubber. However, in order to keep the quality constant, it is desirable to use a single waste rubber. The waste rubber is formed into chips in advance using a breaker or the like. The tip is preferably sized on average (preferably substantially) to 1 to 4 mm. This is because a chip having a size exceeding 4 mm causes a large shearing load due to the multi-screw extruder and cannot be efficiently plasticized, while a chip smaller than 1 mm is extremely difficult to process with a breaker or the like. And
Also, in a multi-screw extruder, it is difficult to apply shearing, and sufficient plasticization cannot be performed. Therefore, the size of the rubber chip is desirably within the above range.

[0006] The multi-screw extruder for shearing waste rubber chips has at least two shafts, each of which is provided with a stirring blade such as a screw or a protrusion, and the respective shafts are the same during operation. The waste rubber chip is rotated in the direction or the opposite direction, and is moved downstream while applying pressure to the waste rubber chip with a screw or the like. In the multi-screw extruder, a large shearing force is obtained by, for example, screws provided on the respective shafts meshing with each other, and the waste rubber chips can be pulverized and plasticized without heating. At the time of this shearing, it is necessary to avoid applying external heating in order not to lower the quality of the recycled rubber and to make it easier to apply the shearing.
In addition, at the time of the above-mentioned shearing, internal heat is generated due to friction. Therefore, it is desirable to cool the extruder (cylinder or shaft) with a cooling device so as to suppress the temperature rise of the waste rubber chips during the shearing. By this cooling, the waste rubber chip is reduced to 50 to 1
It is desirable to adjust to 00 ° C. This is because if the temperature exceeds 100 ° C., the rubber is excessively broken and the quality is deteriorated. On the other hand, if the temperature is lower than 50 ° C., a large shearing force is required and the load on the extruder becomes excessive. Waste rubber chips are pulverized by shearing with the multi-screw extruder.
mm or less. This is because if the fine particles are larger than 0.8 mm, the plasticization is insufficient and the vulcanized rubber remains, and the smaller the fine particles, the more plasticized the smaller the fine particles. It is desirable that the presence ratio of the fine particles is 0.1 mm or less.

[0007] The fine rubber particles obtained as described above can be used for various applications as powder rubber as it is. Plasticization can be promoted by further mixing and kneading a regenerant. As the regenerating agent, those conventionally used such as process oil, n-butylamine, thiophenol and the like can be used. The amount of the regenerating agent varies depending on the type of the regenerating agent.
l, n-Butylamine 10 g of regenerant are charged. In the present invention, since a certain amount of plasticization is performed in the former stage, the mixing amount of the regenerating agent can be smaller than that of the conventional method, and as a result, the quality of the recycled rubber can be improved.

[0008] The kneading can be performed by a roll or a multi-screw extruder, or the kneading may be continuously performed by a multi-screw extruder that has been subjected to the shearing. In the kneading by these methods, similarly to the above-mentioned shearing, it is desirable to provide a cooling device so as not to apply external heating and further suppress the temperature rise of the rubber powder. In this kneading, it is desirable to adjust the temperature of the rubber so as to be in the range of room temperature to 50 ° C. during kneading.
Even if the upper limit of the temperature in kneading is regulated in this manner, plasticization proceeds sufficiently to some extent due to mechanical shearing in the preceding process. The reclaimed rubber mass obtained as a result of kneading is preferably in the form of a plate having a thickness of about 1 mm.

[0009] The above kneading together with the above-mentioned shearing,
When a common multi-screw extruder is used, a recycled area can be produced by a continuous series of operations by allocating a shearing region upstream of the extruder and a kneading region downstream. In the shearing region and the kneading region,
For example, the screw shape, pitch, structure such as pitch, depth, etc. can be changed, and temperature control may be controlled in both regions, respectively. The temperature adjustment can be the same. Further, in the extruder, a waste rubber charging section is provided on the upstream side of the shearing area, a regenerating agent charging section is provided near a boundary between the shearing area and the kneading area, and a recycled rubber take-out section is provided on the downstream side of the kneading area. .

The waste rubber charging section can be constituted by a hopper or the like, but the structure of the present invention is not particularly limited. Further, the regenerant supply section provided near the boundary between the shearing region and the kneading region is provided between the terminal end of the shearing region and the starting end of the kneading region when the boundary between the two appears clearly. In this case, a regenerating agent introduction portion can be provided at an appropriate position, and when the boundary between the two is not clear, an appropriate position is determined as a boundary portion in consideration of a change in operation in each region, and the introduction portion is defined. Can be provided. The reclaimed rubber take-out part is usually provided at the end of the kneading area. In the waste rubber charging unit, the regenerating agent charging unit, and the recycled rubber discharging unit, it is desirable to control the charging amount and the discharging amount individually or in association with each other so that shearing and kneading are appropriately performed.

As described above, rubber plasticized by mechanical shearing and rubber kneaded by mixing with a regenerant in addition to this can be produced by an efficient process in a short time or continuous operation. it can. Moreover, since these rubbers are plasticized by shearing without external heating, deterioration of rubber quality due to heating is small,
Also, there is no mixing of rubber powder, and it has excellent quality as recycled rubber. Further, in the case where the regenerant is mixed and kneaded after mechanical shearing, the plasticization is sufficiently performed without the need for external heating, so that the Mooney viscosity becomes small and the processing becomes easy.

[0012]

(Embodiment 1) An embodiment of the present invention will be described below with reference to FIG. In the extruder 1 used in this embodiment, two screw shafts 3a and 3b are arranged in a cylinder 2, and the screw shafts 3a and 3b are
3b is configured so that the screw blades of each other mesh slightly with each other and rotate in the same direction. In addition, the extruder 1 is provided with a hopper 4 for charging a raw material and a take-out unit 5 for taking out finely ground rubber powder. Prior to the shearing by the extruder 1, the waste tire is broken into rubber chips 10 having a size of substantially 1 to 4 mm by a breaker, and this is cut into a cylinder 2 of the extruder 1.
Put in. The inserted rubber chip 10 is mechanically sheared by the rotating two screw shafts 3a and 3b, and is finely pulverized into a rubber powder 10a having a size of substantially 0.8 mm or less. The obtained rubber powder 10a is
It can be used for various applications as it is.

(Embodiment 2) The rubber powder 10a
, A regenerant is mixed as shown in FIG.
2 can be kneaded by passing it between the rolls 13 to obtain a plate-shaped reclaimed rubber mass 15 having a thickness of about 1 mm.

(Embodiment 3) FIG. 3 is different from the embodiment shown in FIG. 2 in that the rubber powder 10a is fed into a cylinder 22 together with a regenerant through a hopper 22 of a twin-screw extruder 20, and Kneading is performed by the screw shafts 23a and 23b. The regenerant is kneaded with the rubber powder 10a in the cylinder 21 of the twin-screw extruder 20. Due to this kneading, the rubber powder 10a moves in the cylinder 21 while being plasticized, and finally,
Recycled rubber blocks 25 having a size of about 10 cm ^{3 to} about 10 cm ³ are continuously obtained. Reclaimed rubber 15 or reclaimed rubber 25 obtained by kneading in roll 13 or twin-screw extruder 20
Has excellent quality without deterioration of the quality or mixing of rubber powder. In addition, the recycled rubber is sufficiently plasticized, and can be easily processed and reused for reuse according to the purpose of use.

(Embodiment 4) In this embodiment, as shown in FIG.
0 is sheared and kneaded. The twin screw extruder 30
Are two screw shafts 32 a, 32 in a cylinder 31.
b are arranged in parallel, and each screw blade is arranged so as to partially mesh with each other. Also, the cylinder 31
Is a shearing area 31a on the upstream side and a kneading area 31b on the downstream side.
, And the shapes of the screw shafts 32a and 32b are selected according to the respective areas. On the upstream end side of the shearing region 31a, a hopper 33 for charging the rubber chip 10 into the cylinder 31 is provided. In addition, a regenerant is injected into the cylinder 31 at the boundary between the shearing region 31a and the kneading region 31b. And a reclaimed rubber take-out section 35 for taking out a reclaimed rubber mass at the downstream end of the kneading area 31b.

The production of recycled rubber using the above apparatus will be described.
Into the hopper 33 continuously, while the screw shaft 3
2a and 32b are rotated in the same direction. The waste rubber chips 10 put into the hopper 33 sequentially move in the cylinder 31 and, similarly to the first embodiment, the shearing region 3 in the extruder.
It is sheared at 1a and pulverized into rubber particles 10a of a desired size. The rubber particles 10a move inside the cylinder 31. From the shearing area 31a to the kneading area 31b. At the boundary between these regions 31a and 31b, the regenerant is continuously supplied from the regenerant supply portion 34 into the cylinder 31, and the regenerant is sequentially supplied to the rubber particles 10a moving within the cylinder 31. Mixed. The rubber particles mixed with the regenerating agent move in the kneading area 31b while moving in the screw shafts 32a, 3b.
The mixture is stirred and mixed by 2b, the regenerant and the rubber powder are uniformly dispersed, and the desulfurization (plasticization) of the rubber powder proceeds. In addition,
The cylinder 31 is provided with a cooling device (not shown), and the operation of the cooling device suppresses a temperature rise in the cylinder 31. The reclaimed rubber mass 36 sufficiently plasticized as described above is taken out of the cylinder 31 from the reclaimed rubber take-out portion 35, processed as needed, and used for a desired application. In the production of the recycled rubber using the extruder 30, the recycled rubber can be efficiently produced,
The obtained reclaimed rubber is sufficiently plasticized, and the degradation of quality due to reclaiming is small. In the above-described embodiment, the two screw shafts are arranged so that the respective screws partially mesh with each other, and are engaged in the same direction. However, as the present invention, the meshing state and the rotation direction are appropriately changed. be able to.

[0017]

Embodiments of the present invention will be described below. A waste rubber chip obtained by breaking a waste rubber obtained from a truck or a passenger tire into a size of 1 to 4 mm is prepared.
Recycled rubber was produced from g by the bread method according to the present invention and the conventional method. In the method of the present invention, the waste rubber chip is broken into a size of 1 to 4 mm by the twin-screw extruder described in Embodiment 4 to produce finely pulverized rubber particles, and a regenerating agent (100 ml of process oil, n-butylamine (10 g) was mixed and kneaded with a roll to produce a recycled rubber. On the other hand, in the pan method, the waste rubber chips
And the resulting rubber was ground by a roll mill to produce recycled rubber.

In order to evaluate the quality (plasticization) of the reclaimed rubber obtained above, the amount of chloroform extracted from the waste rubber as a raw material and the reclaimed rubber obtained by each method was measured (measurement method: JIS K6350). For reference, the amount of chloroform extracted from the finely ground rubber particles after shearing was also measured in the method of the present invention, and the results are shown in Table 1. As a result, in the method of the present invention, as a result of the regeneration, the amount of chloroform extracted was significantly increased, and thus it was shown that plasticization was sufficiently advanced. On the other hand, in the pan method, the amount of chloroform extracted is slightly increased and plasticization is not sufficient. Also, up to the production of recycled rubber,
While the process of the present invention completed the process in about 30 minutes, the pan method requires 4 hours, and it is clear that there is a remarkable difference in working efficiency. In addition, the recycled rubber obtained by the method of the present invention was sufficiently plasticized as described above, and neither residual rubber powder nor excessive breaking of rubber molecules was observed.

[0019]

[Table 1]

[0020]

As described above, according to the method for producing recycled rubber of the present invention, the vulcanized waste rubber chips are plasticized while being finely pulverized by the shearing force of the multi-screw extruder without applying external heating. As a result, finely pulverized rubber particles can be obtained, so that plasticization can be favorably performed without deteriorating the rubber quality. Furthermore, if a regenerant is mixed and kneaded with the rubber particles, a regenerated rubber excellent in quality and sufficiently plasticized can be obtained.

It is to be noted that, in the above-mentioned production, a multi-shaft mixer having a multi-shaft screw arranged in a cylinder is provided.
The cylinder is divided into an upstream shearing region and a downstream kneading region, and a waste rubber charging section for charging vulcanized waste rubber into the cylinder is provided in the shearing region, and a shearing region and a kneading region are provided. A manufacturing apparatus provided with a regenerating agent introducing section for introducing a regenerating agent into a cylinder near a boundary portion with the reclaimed rubber, and a reclaimed rubber take-out section for taking out reclaimed rubber from the inside of the cylinder on a downstream side of the kneading region. By using, it is possible to efficiently produce a regenerated rubber having good quality and sufficiently plasticized as described above.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing one embodiment of the present invention.

FIG. 2 is a schematic view showing another embodiment.

FIG. 3 is a schematic view showing still another embodiment.

FIG. 4 is a schematic view showing still another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Twin screw extruder 2 Cylinder 3a Screw shaft 3b Screw shaft 4 Hopper 5 Reclaimed rubber take-out part 10a Finely ground rubber particles 13 Roll 15 Reclaimed rubber lump 20 Twin screw extruder 21 Cylinder 22 Hopper 24 Reclaimed rubber take-out part 25 Reclaimed rubber lump 30 Twin screw extruder 31 Cylinder 31a Shearing area 31b Kneading area 32a Screw axis 32b Screw axis 33 Hopper 34 Regenerant input section 35 Recycled rubber take-out section 36 Recycled rubber block

Claims (3)

[Claims] 1. A method for producing a reclaimed rubber, wherein pulverized waste rubber chips are plasticized while being finely pulverized by a shearing force of a multi-screw extruder without applying external heating to obtain finely pulverized rubber particles. 2. A method for producing a recycled rubber, comprising: mixing and kneading a plasticizer with the finely pulverized rubber particles according to claim 1; 3. A multi-shaft mixer in which a multi-shaft screw is arranged in a cylinder, wherein the cylinder is divided into an upstream shearing area and a downstream kneading area. A waste rubber charging unit for charging vulcanized waste rubber into the cylinder is provided, and a regenerating agent charging unit for charging the regenerating agent into the cylinder is provided near a boundary between the shearing region and the kneading region. An apparatus for producing a recycled rubber, wherein a downstream side of the cylinder is provided with a recycled rubber take-out portion for taking out the recycled rubber from the cylinder.