JP5860290B2 - Method and apparatus for producing rubber material with reduced impurity content - Google Patents

Description

  The present invention relates to a manufacturing method and a manufacturing apparatus for high-purity rubber material (hereinafter also simply referred to as “manufacturing method” and “manufacturing apparatus”), and more specifically, a high-purity rubber material is obtained by removing impurities in the rubber material. The present invention relates to a manufacturing method and apparatus.

  In general, when a rubber material such as natural rubber is used for manufacturing a rubber product such as a tire, it is necessary to remove impurities mixed in the rubber material. In order to remove fine impurities such as stones, sand, and wood chips, the rubber material is pulverized and finely divided, and the finely divided rubber material is washed in a water-washing pool and the like, and the impurities exposed on the crushing surface The method of peeling and separating is used. In this method, as a pulverizer for pulverizing a rubber material, a general-purpose pulverizer such as a hammer mill or an extruder is conventionally used when crushing rubber products.

  There is also a method in which the rubber material is passed through a strainer to filter out solid impurities contained in the rubber material. In this method, the rubber material passes through the strainer by applying a strong pressure, while impurities that are solids do not pass through the strainer, so that impurities larger than the mesh size of the strainer can be easily removed.

  As a technique related to the processing of a rubber material, for example, Patent Document 1 discloses a facility for processing used rubber and used rubber products by low-temperature pulverization a plurality of times, and a low-temperature cooling device for cooling a material to be pulverized. And a facility for processing used rubber of a type provided with a foreign matter separator and a classifier.

JP-T-2004-511344 (Claims etc.)

  Among the above, according to the method of cleaning the rubber material after pulverization, impurities contained in the rubber material can be effectively removed by exposing the surface to the surface by making the rubber material finer. However, rubber materials, particularly unvulcanized rubber such as natural rubber, have a problem that it is difficult to make fine particles due to strong adhesiveness and adhesion, and conventional pulverizers have a problem of up to about 3 to 6 mm square. Refinement was the limit. Therefore, since finer impurities cannot be exposed to the crushing surface, there is a limit to the resulting impurity removal rate. On the other hand, even if the conditions such as the flow rate during washing were changed, the amount of residual impurities could not be reduced further.

  In addition, the method of passing the strainer has a problem that a large amount of energy is required and production efficiency is greatly reduced because the rubber material is passed through the mesh. Further, when impurities are accumulated on the strainer, the rubber material does not pass through the strainer, so that it is necessary to periodically replace the strainer.

  Therefore, conventional impurity removal technology is not sufficient, and establishment of a technology for obtaining a high-purity rubber material by further reducing the amount of impurities in the rubber material without causing the above-described problems is required. It was done.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method and an apparatus for producing a high-purity rubber material that solves the above-mentioned problems and can efficiently and easily remove impurities in the rubber material at a high removal rate. It is in.

  As a result of intensive studies, the present inventor has determined that when removing impurities from the rubber material using a method of washing the rubber material after pulverization, the rubber material is pulverized by a pulverizer equipped with a specific combination of a fixed blade and a rotary blade. As a result, the present inventors have found that the above problems can be solved, and have completed the present invention.

That is, the method for producing a rubber material with reduced impurity content according to the present invention comprises a pulverization step of pulverizing and finely pulverizing a rubber material containing impurities, and the impurities adhering to the pulverized rubber material. A removing step for removing, and performing the removing step after or simultaneously with the crushing step to produce a rubber material having a reduced content of the impurities,
In the pulverization step, using a pulverizer provided with a cylindrical screen provided with a large number of through holes provided with cutting edges at the edges, and an inner blade capable of high-speed rotation provided radially in the screen. The rubber material is pulverized by sliding contact between the inner blade and the inner peripheral surface of the screen.

  In the production method of the present invention, in the pulverization step, the rubber material can be finely divided into 0.5 to 3 mm square. Further, in the production method of the present invention, in the removing step, it is preferable to wash the finely divided rubber material before the finely divided rubber material is agglomerated, in particular, a jet water flow device or a water flow pump. The finely divided rubber material is preferably washed with water using a pool provided with a washing machine or a washing machine with a dehydrating function. Furthermore, in the production method of the present invention, the foreign matter ratio in the finely divided rubber material from which the impurities are removed can be set to a range of 0.2% or less.

The apparatus for producing a rubber material with reduced impurity content according to the present invention comprises a pulverizer for pulverizing and finely pulverizing a rubber material containing impurities, and the impurities adhering to the pulverized rubber material. An apparatus for producing a rubber material with a reduced content of the impurities, comprising a remover for removing,
The pulverizer includes a cylindrical screen having a plurality of through holes provided with a cutting edge at an edge, and an inner blade capable of high-speed rotation provided radially in the screen, The rubber material is pulverized by sliding contact with the inner peripheral surface of the screen.

  In the production apparatus of the present invention, it is preferable that the pulverizer can finely pulverize the rubber material into 0.5 to 3 mm square. In the production apparatus of the present invention, the removing machine is preferably a washing type removing machine that removes the impurities by washing the finely divided rubber material, and in particular, a jet water flow device or a water flow pump. It can be a pool provided or a washing machine with a dehydrating function. Furthermore, in the manufacturing apparatus of the present invention, the removal rate of impurities in the remover can be in the range of 0.2% or less in terms of the foreign matter rate in the finely divided rubber material.

  In this invention, it is preferable that the said cutting blade consists of a horizontal blade provided along the circumferential direction of the said screen, and a vertical blade provided along the height direction of this screen.

  According to the present invention, with the above-described configuration, it is possible to realize a method and an apparatus for manufacturing a high-purity rubber material that can efficiently and easily remove impurities in the rubber material with a high removal rate. It has become possible.

It is a schematic explanatory drawing which shows one structural example of the manufacturing apparatus of the high purity rubber material of this invention. It is a top view which expands and shows the principal part of an example of the grinder which concerns on this invention. It is a fragmentary perspective view which expands and shows the principal part of an example of the grinder which concerns on this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In FIG. 1, the schematic explanatory drawing which shows one structural example of the manufacturing apparatus of the high purity rubber material of this invention is shown. The apparatus for producing a high-purity rubber material according to the present invention includes a pulverizer 10 for pulverizing and finely pulverizing a rubber material containing impurities, and a remover 20 for removing impurities adhering to the pulverized rubber material. Is.

  FIG. 2 is an enlarged cross-sectional view showing a main part of an example of a pulverizer according to the present invention. As shown in the figure, a pulverizer 10 according to the present invention includes a cylindrical screen 3 having a plurality of through holes 2 provided with cutting edges 1a and 1b (cutting heads) at the edges, and a radial shape within the screen 3. And an inner blade (impeller) 4 that can be rotated at a high speed. In FIG. 3, the schematic perspective view which expands and shows the principal part of an example of the grinder which concerns on this invention is shown. G in the figure indicates a rubber material, and g indicates a crushed rubber material.

  In the illustrated pulverizer 10, the cutting blades 1 a and 1 b provided on the screen 3 have a function as fixed blades arranged in a cylindrical shape. When the rubber material is put into the screen 3 and the radially provided inner blade 4 is rotated, the charged rubber material G rotates at a high speed as the inner blade 4 rotates, and the centrifugal force generated thereby. Is pushed toward the inner peripheral surface of the screen 3. The rubber material G pushed to the inner peripheral surface of the screen 3 is lowered between the inner blade 4 and the cutting blades 1a, 1b by sliding contact between the inner blade 4 and the inner peripheral surface of the screen 3. The crushed and crushed rubber material g passes through the through hole 2 and is discharged to the outside of the screen 3.

  Since the pulverizer 10 is configured as described above, the rubber material G can be efficiently cut and pulverized between the inner blade 4 and the cutting blades 1a and 1b, and the inner blade 4 can be rotated at high speed. Therefore, the rubber material can be cut before being kneaded, and the rubber material can be refined to a particle size of about φ3 mm or less, which could not be realized with a general-purpose pulverizer such as a conventional hammer mill or extruder. Became possible. As a result, even finer impurities can be exposed on the crushing surface of the rubber material, so that the impurity removal rate can be greatly improved as compared with the conventional case. Further, by making the rubber material finer, it is possible to further reduce the average value and variation of the foreign matter rate of the obtained high-purity rubber material.

  In the present invention, the cutting blade provided at the edge of the through hole 2 is preferably formed along the circumferential direction of the screen 3 and the vertical blade 1a provided along the height direction of the screen 3, as shown in the figure. It shall consist of the provided horizontal blade 1b. A piece of rubber material that is crushed between the cutting blades 1a, 1b and the inner blade 4 and passes through the through-hole 2 by making the cutting blade as a fixed blade to be composed of the vertical blade 1a and the horizontal blade 1b. Can be further miniaturized, which can contribute to an improvement in impurity removal rate, which is preferable.

  In the present invention, the interval between the vertical blades 1a and the horizontal blades 1b provided on the screen 3 is usually uniform, and in order to obtain a finely divided rubber material of about 3 mm square or less by the pulverizer 10, the vertical blades 1a are used. And the gap between the horizontal blades 1b is preferably 2 mm or less, and more preferably in the range of 1 to 2 mm. If the interval between the cutting edges is too wide, it is difficult to make the rubber material finer in the above range. On the other hand, even if the interval between the cutting edges is too narrow, the rubber is not discharged, causing a decrease in productivity. According to the present invention, the pulverizer 10 can make the rubber material finer to 3 mm square or less, particularly 0.5 to 3 mm square.

  Moreover, in this invention, the inner blade 4 is comprised so that high-speed rotation is possible, As a rotation speed of the inner blade 4, it is set as 4000 rpm (100 km / h) or more, especially 4700 rpm or more, Furthermore, it is set as the range of 4700-6000 rpm. It is preferable. If the rotational speed of the inner blade 4 is too low, the rubber may not be cut, which is not preferable. On the other hand, even if the rotational speed of the inner blade 4 is too high, the mechanical vibration increases and causes damage. In the pulverizer 10, the size of the screen 3 is not particularly limited, but a smaller size of the screen 3 is preferable because the average value and variation of the foreign matter rate of the high-purity rubber material to be obtained can be reduced. .

  As the pulverizer according to the present invention, for example, as a commercial product, the COMITOLOL series manufactured by Archer Japan, which is mainly used in the food industry, can be preferably used.

  In the production apparatus of the present invention, the impurities adhering to the rubber material refined by the pulverizer 10 are removed by the remover. Such a removal machine may be any one that can remove impurities exposed on the crushing surface of the rubber material, but preferably, the finely divided rubber material is washed with water. Thus, a washing type removing machine for removing impurities is obtained. As the machine for removing impurities by washing with water, any machine can be used as long as it has a function of separating rubber and impurities by giving an impact to the rubber material, and can generate a strong water flow. preferable. As such a removal machine, specifically, for example, a jet water flow device 21 as shown in FIG. 1 or a pool 20 equipped with a water flow pump can be suitably used, and swirl like a washing machine with a dewatering function can be used. An apparatus capable of giving an impact to the rubber material by generating it is also effective. By using these removers, it is possible to easily and easily remove impurities from the rubber material.

Next, the manufacturing method of the high purity rubber material of this invention is demonstrated with reference to FIG.
The manufacturing method of the present invention is to remove impurities adhering to the finely divided rubber material (removal step) after pulverizing and finely pulverizing the rubber material containing impurities (pulverization step).

  As shown in the figure, in the production method of the present invention, specifically, for example, water is supplied by a pump P, and a rubber material containing impurities is introduced into the water from a rubber supply feeder 22, and the rubber material In a state where water and water are mixed, the pulverizer 10 is charged at a constant speed. The amount of water input to the pulverizer 10 at this time can be, for example, 100 L / min or more, and particularly 100 to 200 L / min.

  As described above, the pulverizer 10 includes a cylindrical screen 3 having a large number of through holes 2 provided with cutting edges 1a and 1b at the edges, and a high-speed rotation provided radially in the screen 3. An inner blade 4 is provided. The rubber material introduced into the pulverizer 10 together with water is pulverized and pulverized by the sliding contact between the inner blade 4 and the inner peripheral surface of the screen 3 (pulverization step). Here, the rubber material put into the manufacturing apparatus of the present invention is adjusted in advance to a size of about 20 to 50 mm square by a pre-grinding process using a general-purpose pulverizer such as a prebreaker, a hammer mill, or an extruder. deep. Although depending on the capacity of the apparatus and the like, if the size of the rubber material to be added is too large, the production yield is lowered. On the other hand, if the size of the rubber material to be added is too small, the number of pretreatment steps increases, which leads to a decrease in production yield, which is not preferable in any case.

  The finely divided rubber material is discharged from the through-hole 2 of the screen 3 and put into a removing machine, in the illustrated example, a pool 20 having a jet water flow device 21 to remove adhering impurities (removal). Process). Since the pulverized rubber material has a large surface area, it has very high adhesion. Therefore, if the crushed rubber material is left as it is, re-adhesion occurs between the crushed rubber materials, and impurities exposed on the surface of the rubber material cannot be removed. Therefore, in order to remove impurities from the finely divided rubber material, it is preferable to perform the removal step immediately after the pulverization step or simultaneously with the pulverization step. From this point of view, it is preferable that the pulverizer 10 and the removing machine 20 are arranged close to each other as shown in the drawing, or the pulverizer and the removing machine are integrated (not shown). Specifically, for example, in an apparatus as shown in the figure, the finely divided rubber material is discharged from below the pulverizer 10 and can be directly put into the removing machine 20, so that the rubber material is immediately In addition, since the impact can be given to the finely divided rubber material by water flow, the separation of the rubber material and the impurities is promoted and the impurities are reliably removed while preventing the reattachment of the finely divided rubber materials. It becomes possible.

  When removing impurities in the illustrated pool 20, the flow rate of water in the pool is adjusted to 0 by adjusting the jet water flow device 21 or the like at the location where the fine rubber material is charged, for example, directly below the crusher 10. .2 m / s or more, particularly 0.2 to 1 m / s, more preferably 0.5 to 1 m / s. The faster the water flow rate at the location where the finely divided rubber material is introduced, the more effectively impurities can be removed before the finely divided rubber material is re-agglomerated. Variations can be reduced. When the flow rate of water is too slow, the impact on the rubber material is too small, and the impurities are not sufficiently separated from the surface of the rubber material, and the impurities may remain on the surface of the rubber material. The length of the pool 20 is preferably 4 m or more, and more preferably about 4 to 10 m. If the length of the pool 20 is too short, the impurities separated from the rubber material may not settle down completely, and may be attached again.

  The pool 20 is preferably provided with a paddle 23 as shown. By providing the paddles 23 at a plurality of places in the pool 20, for example, about 2 to 3 places in a 6 m long pool, the effect of keeping the water flow constant can be obtained. When the paddle 23 is provided, the flow rate of water in the pool downstream from the place where the paddle is provided is preferably 0.1 m / s or less, particularly 0.02 to 0.1 m / s. Note that, whether or not the paddle 23 is used, it does not greatly affect the average value and variation of the foreign matter rate of the obtained high-purity rubber material.

  In the illustrated manufacturing apparatus, the rubber material separated from the impurities by the pool 20 flows into the storage unit 25 provided with the rubber capturing fence 24. Therefore, the rubber material from which impurities are removed can be taken out from the storage unit 25, and a high-purity rubber material can be obtained by appropriately drying the taken-out rubber material. The water flowing into the storage unit 25 together with the rubber material flows out of the storage unit 25 through the mesh of the rubber capturing fence 24, and is supplied to the jet water flow device 21 through the supply unit 26.

  According to the present invention, it is possible to reduce the foreign matter rate in the rubber material to about half or less compared to the conventional one. Specifically, as a removal rate of impurities in the remover, a finely divided rubber material It is possible to achieve a foreign matter ratio in the range of 0.2% or less, particularly 0.1% or less. Here, the foreign matter rate in the rubber material can be determined as follows. First, the dried rubber material (mass M (g)) is heated and decomposed in a high-boiling nonpolar organic solvent such as xylene, and the remaining impurities are filtered through a mesh having an opening of, for example, 47 μm. If the mass of impurities remaining on the mesh is m (g), the foreign matter rate can be obtained by (m / M) × 100 (mass%).

  The rubber material to which the present invention can be applied may be any solid rubber containing impurities and can be pulverized. Specifically, for example, natural rubber containing a large amount of impurities. In addition to (unvulcanized rubber), unvulcanized or vulcanized rubber compositions containing natural rubber and various synthetic rubbers may be mentioned. There is no restriction | limiting in particular also about the use of the high purity rubber material obtained by this invention, It is possible to apply suitably to various rubber products, such as a tire and a bladder for tire manufacture.

  The high-purity rubber material obtained by the present invention has a significantly reduced impurity content as compared with the prior art, and therefore can be suitably used for applications requiring high purity such as tire raw materials. That is, a rubber material having a large amount of impurities can be highly purified by applying the present invention. Therefore, according to the present invention, any rubber material can be used depending on the amount of impurities contained at the beginning. Therefore, it can be used for a wide range of applications. Specifically, for example, according to the present invention, solid natural rubber that has a large amount of impurities but is excellent in transportability and is inexpensive is the same as a liquid natural rubber latex that has a small amount of impurities but is poor in transportability and is expensive. It can be easily purified to a certain extent, and the cost of rubber products using natural rubber can be improved.

Hereinafter, the present invention will be described in more detail with reference to examples.
<Examples 1 and 2>
Impurities were removed from natural rubber using a manufacturing apparatus including a pulverizer 10 and a pool 20 having a jet water flow device as a remover as shown in FIG. The natural rubber was previously adjusted to a size of about 30 mm square using a prebreaker and a hammer mill.

  As the pulverizer 10, Commitol (product number: 3M-020080) manufactured by Urschel Japan Co., Ltd. was used. This crusher is provided with a cylindrical screen having a large number of through-holes provided at its edge with vertical blades along the height direction of the screen and horizontal blades along the circumferential direction of the screen, and radially provided within the screen. And a gap between the vertical blades and the horizontal blades was 3 mm and 2 mm, respectively. The rotation speed of the inner blade was 4700 rpm (110 km / h). Furthermore, the input amount of water to the pulverizer 10 was set to 100 L / min.

  The rubber material finely divided by the pulverizer 10 is directly charged into the pool 20 from the lower opening of the pulverizer 10, and the flow rate of water in the pool at the portion where the finely divided rubber material is charged is By changing the jet water flow device, it was changed as shown in the table below. Moreover, the length of the pool 20 was 6 m. The pool 20 was provided with paddles at three locations, and the flow rate of water in the pool downstream from the locations where the paddles were provided was 0.1 m / s.

<Conventional Examples 1 and 2>
Impurities were removed from the natural rubber in the same manner as in Example except that a general-purpose extruder was used as the pulverizer 10.

<Comparative example>
Impurities were removed from the natural rubber in the same manner as in the example except that the pulverizer 10 was not used and 3 to 6 mm square natural rubber was directly added to the pool 20.

<Evaluation of rubber material size>
The finely divided rubber material before the pool 20 was introduced was collected and evaluated for its size. The results are also shown in the table below.

<Evaluation of foreign matter rate>
The rubber material taken out from the storage unit was dried, heated and decomposed in xylene, and the remaining impurities were filtered through a mesh having an opening of 47 μm. The mass of the dry rubber material was M (g) and the mass of impurities remaining on the mesh was m (g), and the foreign matter rate was determined by (m / M) × 100 (mass%). The results are also shown in the table below.

  As shown in the above table, for the natural rubber crushed with the comitorol according to the present invention, the faster the pool flow rate, the greater the effect of removing impurities. This is considered to be because natural rubber and impurities were effectively separated by applying an impact to the natural rubber by a water flow immediately after the granulation. In contrast, natural rubber crushed with a conventional general extruder did not change the amount of impurities removed even when the flow rate of the pool was changed.

1a, 1b Cutting blade 2 Through-hole 3 Screen 4 Inner blade 10 Crusher 20 Remover (pool)
21 Jet Water Flow Device 22 Rubber Feeder 23 Paddle 24 Rubber Capture Fence 25 Storage Unit 26 Supply Unit

Claims (12)

A pulverizing step of pulverizing and finely pulverizing the rubber material containing impurities, and a removing step of removing the impurities adhering to the pulverized rubber material, the removing step after the pulverizing step or What same time line as the milling process, a process for producing a rubber material content of the impurity is reduced,
In the pulverization step, using a pulverizer provided with a cylindrical screen provided with a large number of through holes provided with cutting edges at the edges, and an inner blade capable of high-speed rotation provided radially in the screen. A method for producing a rubber material with reduced impurity content , characterized in that the rubber material is pulverized by sliding contact between the inner blade and the inner peripheral surface of the screen. 2. The rubber with reduced impurity content according to claim 1, wherein the cutting blade comprises a horizontal blade provided along the circumferential direction of the screen and a vertical blade provided along the height direction of the screen. Material manufacturing method. The method for producing a rubber material with reduced impurity content according to claim 1 or 2, wherein in the pulverizing step, the rubber material is finely divided into 0.5 to 3 mm square. The rubber material with reduced impurity content according to any one of claims 1 to 3, wherein in the removing step, the finely divided rubber material is washed with water before the finely divided rubber material is adhered. Production method. 5. The rubber material with reduced impurity content according to claim 4, wherein, in the removing step, the finely divided rubber material is washed with water using a pool equipped with a jet water flow device or a water flow pump, or a washing machine with a dewatering function. Production method. The foreign material rate in the said finely divided rubber material from which the said impurity was removed is the range of 0.2% or less, The rubber material with reduced impurity content as described in any one of Claims 1-5 Production method. A grinder for grain refining by grinding a rubber material containing impurities, Ru and a removal device for removing the impurities attached to the rubber material is comminuted, the content of the impurity is reduced rubber A material manufacturing device,
The pulverizer includes a cylindrical screen having a plurality of through holes provided with a cutting edge at an edge, and an inner blade capable of high-speed rotation provided radially in the screen, An apparatus for producing a rubber material with reduced impurity content , characterized in that the rubber material is pulverized by sliding contact with an inner peripheral surface of the screen. 8. The rubber with reduced impurity content according to claim 7, wherein the cutting blade comprises a horizontal blade provided along the circumferential direction of the screen and a vertical blade provided along the height direction of the screen. Material production equipment. The apparatus for producing a rubber material with reduced impurity content according to claim 7 or 8, wherein the pulverizer is capable of making the rubber material finer into 0.5 to 3 mm square. The rubber material with reduced impurity content according to any one of claims 7 to 9, wherein the removing machine is a water-washing type removing machine that removes the impurities by washing the finely divided rubber material. manufacturing device. 11. The apparatus for producing a rubber material with reduced impurity content according to claim 10, wherein the removing machine is a pool provided with a jet water flow device or a water flow pump, or a washing machine with a dewatering function. The impurity removal rate in the said removal machine is the range of 0.2% or less by the foreign material rate in the said granulated rubber material, The impurity content as described in any one of Claims 7-11 was reduced. Rubber material manufacturing equipment.

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