JP2006075711A - Rubber composition and pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a rubber composition which is made to keep the failure characteristic higher than those of the conventional reclaimed rubber and powdery rubber so that consequently the material recycling rate of waste rubber can be improved, and to provide a pneumatic tire. <P>SOLUTION: The rubber composition contains the rubber powder obtained by pulverizing rubber chips. The rubber powder is manufactured by using a method for pulverizing rubber chips, which comprises: a coarse crushing step A of coarsely crushing rubber chips repeatedly once or more times to form into fine powder, a fine powder recovering step of collecting/recovering the fine powder obtained by coarsely crushing rubber chips; a secondary crushing step of furthermore crushing the recovered fine powder into particulate powder; a secondarily particulate powder recovering step of collecting/recovering the particulate powder crushed at the secondary crushing step; and a product step of screening the final particulate powder by using a filter having a predetermined mesh and withdrawing undersize powder. The coarse crushing step and the secondary crushing step are carried out by using a diamond-electrodeposited rotary drum and a diamond-electrodeposited fixed edge. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rubber composition and a pneumatic tire (hereinafter, also simply referred to as “tire”), and in particular, maintains high fracture characteristics and improves the recycling rate of waste rubber obtained from rubber products such as used tires. The present invention relates to a rubber composition containing powder rubber and a pneumatic tire using the same.

  Waste tires have a higher recovery rate than ordinary plastic products, and are reused as fuel, especially in cement factories. However, in recent years, with the increase of environmental problems, there is a demand for improvement of so-called material recycling rate using tire rubber pieces or rubber powder as they are. In particular, a typical method for obtaining rubber powder is roll crushing, but the conventional method has a large heat history during crushing, and it is basically difficult to reduce the particle size. There has been a problem that the rubber properties (particularly, the fracture properties) are inevitably deteriorated simply by adding the obtained rubber powder to the new rubber. On the other hand, heat desulfurization treatment of rubber powder by an oil pan method is known as a technique for preventing deterioration of processability. In this method, the rubber powder after roll pulverization is treated as it is. Since this is a normal method, deterioration of physical properties is still inevitable.

  On the other hand, for example, in Patent Document 1, it is possible to maintain high fracture characteristics and to improve recycling of rubber products such as used tires without impairing processability as compared with conventional recycled rubber and powder rubber. For the purpose of obtaining a rubber composition containing recycled rubber, the powdered rubber prepared so as to contain 25% or more of particles that have been subjected to a fine particle size treatment and passed through a 145 mesh sieve is further subjected to an oil pan treatment. A reclaimed rubber-containing rubber composition containing the reclaimed rubber obtained as described above is described.

  As mentioned above, sufficient rubber properties, especially fracture properties, are secured in rubber compositions using waste rubber obtained from used rubber products in response to the recent demand for improved material recycling of used rubber products. Thus, a technique for obtaining a more useful rubber composition than before has been demanded.

  Therefore, an object of the present invention is to maintain high fracture characteristics as compared with conventional recycled rubber and powder rubber, thereby improving the material recycling rate of waste rubber obtained from rubber products such as used tires. The object is to provide a rubber composition and a pneumatic tire.

  As a result of diligent investigations to solve the above problems, the present inventor obtained rubber powder from a rubber chip of waste rubber using a novel production method shown below, and has high fracture characteristics in a rubber composition using the same. The present invention has been completed.

That is, the rubber composition of the present invention is a rubber composition containing a powder rubber obtained by pulverizing a rubber chip, and the powder rubber is
A coarse pulverization step in which the rubber chips are repeatedly coarsely pulverized and pulverized one or more times, a fine pulverization recovery step in which the coarsely pulverized and pulverized powder is collected by dust collection, and a secondary pulverization step in which the recovered fine powder is further pulverized. And a secondary pulverization and recovery step in which the finely pulverized product in the secondary pulverization step is sucked and recovered, and the secondary pulverized material that is not recovered is sent again to the secondary pulverization step, and finally pulverized And a step of removing the product through a filter of a predetermined mesh, and the coarse pulverization step and the secondary pulverization step are manufactured using a rubber chip fine pulverization method including pulverization with a diamond electrodeposition rotating drum and a diamond electrodeposition fixed blade It is characterized by being made.

  In the present invention, it is preferable that the coarse pulverization step, the secondary pulverization step, and the product step include an additional step of mixing a separating material such as calcium carbonate or carbon black.

The rubber composition of the present invention is a rubber composition containing a powder rubber obtained by pulverizing rubber chips, and the powder rubber is
Coarse pulverization mechanism that pulverizes and pulverizes the rubber chip once or more, fine pulverization recovery mechanism that absorbs and collects the coarsely pulverized fine powder, and a secondary pulverization mechanism that further pulverizes the recovered fine powder A secondary pulverization and recovery mechanism for sucking and recovering the finely pulverized material by the secondary pulverization mechanism, and sending the secondary pulverized material not recovered again to the secondary pulverization mechanism; And a product mechanism that takes out the product through a filter of a predetermined mesh, and contains a rubber powder produced using a rubber chip pulverizing apparatus.

  In the present invention, the coarse pulverization mechanism and the secondary pulverization mechanism include a diamond electrodeposition rotary drum in which diamond grains are electrodeposited and fixed on a drum peripheral surface that can be driven and rotated, and a predetermined gap on the drum peripheral surface. It is preferable to have a diamond electrodeposition fixing blade provided with an arc surface facing each other and electrodepositing diamond grains on the arc surface.

  The diamond electrodeposition rotating drum and the diamond electrodeposition stationary blade preferably each have a cooling means, and the coarse pulverization mechanism, the secondary pulverization mechanism, and the product mechanism are separated materials such as calcium carbonate and carbon black. It is also preferable to have an additional mechanism for mixing.

  Furthermore, the rubber composition of the present invention preferably contains 75% by weight or more of the powder rubber that has passed through a 100 mesh filter.

  The pneumatic tire of the present invention is characterized by using the rubber composition of the present invention.

  According to the rubber chip fine pulverization method according to the present invention, the rubber chip initially scraped by the diamond electrodeposition rotating drum and the diamond electrodeposited stationary blade is repeatedly sent to the diamond electrodeposited rotating drum and the diamond electrodeposited stationary blade. In addition, since it was repeatedly crushed as if grinding with a stone mill, it was possible to reliably and quickly pulverize rubber chips at room temperature, and to collect the obtained fine powder by collecting dust. Therefore, it is possible to obtain an extremely high quality pulverized rubber powder having a constant particle size. Therefore, since the rubber composition of the present invention containing this rubber powder is extremely excellent in fracture characteristics as compared with the conventional one, it can contribute to the improvement of the material recycling rate of rubber products such as used tires. The pneumatic tire of the present invention using the rubber composition of the present invention has sufficient durability as compared with a tire using only new rubber. In addition, the powder rubber according to the present invention can be added without any problem in the step of kneading the polymer and filler during the production of the rubber composition.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
The rubber composition of the present invention is a rubber composition containing powder rubber obtained by pulverizing waste rubber rubber chips obtained from rubber products such as used tires, and the powder rubber is a rubber chip described later. It is characterized in that it is manufactured using a pulverization method.

  The rubber type of the rubber chip of the waste rubber used as the raw material of the powder rubber according to the present invention is not particularly limited as long as it contains at least one selected from natural rubber and synthetic rubber. The synthetic rubber is preferably a diene rubber such as cis-1,4-polyisoprene, styrene-butadiene copolymer, low cis-1,4-polybutadiene, high cis-1,4-polybutadiene, or ethylene-propylene. -Diene copolymer, chloroprene rubber, halogenated butyl rubber, acrylonitrile-butadiene rubber and the like can be exemplified.

  Vulcanized rubber used as raw material for powder rubber includes silane coupling agents, sulfur, vulcanizing agents, vulcanization accelerators, vulcanization accelerators, antioxidants, and ozone degradation inhibitors that are commonly used in the rubber industry. Anti-aging agent, process oil, zinc white (ZnO), stearic acid, peroxide and the like are blended.

  In the present invention, not only powder rubber obtained from rubber chips such as waste rubber tires and tubes made of such vulcanized rubber, but also from rubber chips such as unvulcanized scrap generated during tire manufacture, spew pieces generated during tire vulcanization The resulting rubber powder can also be used.

  The rubber chip fine pulverization method according to the present invention includes a rubber chip coarse pulverization step, a coarsely pulverized fine pulverization recovery step, a recovered secondary pulverization step, a secondary pulverized secondary fine pulverization recovery step, and And a product step of taking out the finely pulverized product through a predetermined mesh filter. The coarse pulverization step and the secondary pulverization step are faced with a diamond electrodeposition rotary drum formed by electrodeposition fixing diamond grains on a drum circumferential surface that can be driven and rotated, and a predetermined gap on the drum circumferential surface. Grinding with a diamond electrodeposition fixed blade provided with an arc surface and electrodepositing diamond grains on the arc surface is included.

  FIG. 1 is a process diagram showing a preferred embodiment of the present invention. In the figure, symbol A is a coarse pulverization step having a coarse pulverization mechanism, B is a fine pulverization recovery step having a fine pulverization recovery mechanism, and C is a D indicates a secondary pulverization process having a secondary pulverization mechanism, D indicates a secondary pulverization recovery process having a secondary pulverization recovery mechanism, and E indicates a product process.

  In the coarse pulverization step A, reference numeral 1 denotes a chip feeder including an elevator that fixes a plurality of cups to a belt at an appropriate interval and rotates endlessly to convey a rose, and a rubber chip G is attached to a hopper 2 attached to the elevator. Is inserted into the hopper 5 of the coarse crushing mechanism 4 through the supply pipe 3 from the upper part of the elevator. Here, as the rubber chip G, the bead is removed from the waste tire and is cut into pieces, and the waste rubber tube, the unvulcanized scrap, the spew piece generated at the time of tire vulcanization, etc. It is possible to use a metal member or the like that has been extracted from the same and chopped in the same manner.

  As shown in detail in FIG. 2, the coarse pulverization mechanism 4 includes a pulverizer outer box 8 in which a hopper 5 and a delivery pipe 7 are connected to a frame base 6 or the like disposed in the vicinity of the chip feeder 1. And a screw for connecting the hopper 5 and the lower part of the crusher outer box 8 to the side of the frame base 6. A conveyor 11 is provided.

  The screw conveyor 11 is composed of a tube body containing a screw shaft having a drive motor on the upper end side, and moves the rubber chip G discharged from the discharge tube 12 connected to the lower portion of the crusher outer box 8 to move the hopper again. 5 is supplied. Further, a calcium carbonate feeder 13 made of a screw conveyor is connected to the lower end portion side of the tubular body, and this calcium carbonate feeder 13 supplies an appropriate amount of calcium carbonate from the tank 14 into the screw conveyor 11. Calcium carbonate may be changed to carbon black or the like, and these serve as a separating material that reduces the bonding or adhesion between fine powders.

  As shown in the plan view of FIG. 3 and the side view of FIG. 4, the diamond electrodeposition rotating drum 9 has a structure in which, for example, 80 mesh diamond grains are electrodeposited and fixed on the peripheral surface of a drum having a predetermined axial length and diameter. The cooling pipe 16 is inserted through the shaft 15 in the axial direction. An appropriate sprocket is pivotally attached to the shaft 15, and a chain belt 17 is looped endlessly between the sprocket and the sprocket pivotally attached to the reduction shaft of the drive motor 10, so that the diamond electrodeposition rotary drum 9 is outside the grinder. It rotates in the box 8.

  Further, a diamond electrodeposition stationary blade 18 facing the diamond electrodeposition rotary drum 9 with a predetermined gap S is fixed by a mounting plate 19 so that the position of the diamond electrodeposition rotary drum 9 can be adjusted. . The diamond electrodeposited fixed blade 18 is a block body having a substantially rectangular cross section having substantially the same axial length as the diamond electrodeposition rotating drum 9, and the predetermined gap S side is an arc surface along the circumferential surface of the diamond electrodeposition rotating drum 9. For example, 80 mesh diamond grains are electrodeposited and fixed on the arc surface 20. A cooling tube 21 is also inserted through the diamond electrodeposited fixed blade 18 in the longitudinal direction. Reference numeral 22 denotes a fixing bolt, which is inserted into a long hole 23 formed in the diamond electrodeposition fixing blade 18 and screwed to a mounting plate 19 fixed in the crusher outer box 8. Further, as shown in FIGS. 2 and 4, a stopper gilt 19a applied to the diamond electrodeposited fixed blade 18 is fixed to the mounting plate 19 so that the screw can be adjusted, in order to adjust the gap S.

  In the crusher outer box 8, the rubber chip G dropped between the diamond electrodeposition rotating drum 9 and the diamond electrodeposition stationary blade 18 from the hopper 5 is ground by the diamond grains, and is crushed and finely divided. , Micronized. At this time, the diamond electrodeposition rotating drum 9 and the diamond electrodeposition fixed blade 18 are cooled by circulating a cooling medium through the cooling pipes 16 and 21, respectively, and the rubber chip G is melted and formed on the surface thereof. Prevent sticking. The pulverized rubber chip G is sucked by the suction action generated by the air volume control blower 24 provided in the delivery pipe 7 and is pulverized and recovered from the air volume control blower 24 by an appropriate transfer device 25 such as a screw or a conveyor. Sent to B. On the other hand, the coarsely pulverized material that is not sucked and collected is transferred from the discharge pipe 12 at the bottom of the pulverizer outer box 8 into the hopper 5 by the screw conveyor 11, and again the diamond electrodeposition rotary drum 9 and the diamond electrodeposition fixed blade 18. Fall between.

  The pulverizing and collecting step B is provided with a cyclone 27 at the upper part of the silo 26 connected to the transfer device 25 while maintaining a required height, and an outlet 28 at the lower part. It has a fine powder recovery mechanism to which a screw conveyor 29 having substantially the same structure is connected. The screw conveyor 29 is connected to the secondary crushing step C. Accordingly, the roughly crushed rubber chip G is sent from the tank 26 to the second hopper 5a via the screw conveyor 29 and supplied to the fine pulverizing mechanism 4a in the secondary pulverizing step C.

  The fine pulverization mechanism 4a has substantially the same configuration as the coarse pulverization mechanism 4 described above, and a hopper 5a and a second delivery pipe 7a are connected to the second pulverizer outer box 8a, and the second pulverization mechanism 4a is incorporated therein. The second electrode motor 10a for rotating the diamond electrodeposition rotary drum 9a is fixed, and a second screw conveyor 11a is provided on the side of the second frame 6a. The second screw conveyor 11a is a tube body that houses a screw shaft having a drive motor on the upper end side, and lifts the rubber chip discharged from the discharge pipe 12a connected to the lower part of the second crusher outer box 8a. It is moved and supplied to the second hopper 5a again. A second calcium carbonate feeder 13a made of a screw conveyor is connected to the lower end side of the tubular body, and the second calcium carbonate feeder 13a receives an appropriate amount of calcium carbonate from the second tank 14a. It supplies in the screw conveyor 11a. Calcium carbonate may be changed to carbon black or the like, and these serve as a separating material that reduces the bonding or adhesion between fine powders.

  Here, the configuration of the second diamond electrodeposition rotary drum 9a and the second diamond electrodeposition fixed blade 18a is the same as that of the diamond electrodeposition rotary drum 9 and the diamond electrodeposition fixed blade 18 described with reference to FIGS. The structure is exactly the same, with the only difference being that the size of the electrodeposited diamond grains is 120 mesh. The diamond particle size of the diamond electrodeposition rotary drum 9 and the diamond electrodeposition fixed blade 18 in the coarse pulverization mechanism 4 is 80 mesh, whereas the second diamond electrodeposition rotary drum 9a and the second diamond electrodeposition rotation drum 9a and the second in the fine pulverization mechanism 4a. By setting the size of the diamond grains in the diamond electrodeposited fixed blade 18a to 120 mesh, it is possible to achieve extremely high pulverization.

  Therefore, the rubber chip that has fallen between the diamond electrodeposition rotating drum 9a and the diamond electrodeposition fixed blade 18a from the hopper 5a in the crusher outer box 8a is ground by the diamond grains and crushed into fine grains. And it is pulverized. At this time, the diamond electrodeposition rotating drum 9a and the diamond electrodeposition fixed blade 18a are cooled by circulating a cooling medium through the cooling tubes 16a and 21a (not shown), respectively, and the rubber chip is melted, and Prevent sticking. The finely pulverized rubber chips are sucked by the suction action generated by the air volume adjusting blower 24a provided in the delivery pipe 7a, and then secondary pulverized and recovered from the air volume adjusting blower 24a by an appropriate transfer device 25a such as a screw or a conveyor. It is sent to process D. On the other hand, the secondary pulverized material that has not been sucked and collected is transferred from the discharge pipe 12a at the bottom of the pulverizer outer box 8a into the hopper 5a by the screw conveyor 11a, and again the diamond electrodeposition rotary drum 9a and the diamond electrodeposition fixed blade. It falls between 18a.

  In the secondary pulverization and recovery step D, a cyclone 27a is provided at the upper part of the silo 26a that is held at a required height and connected to the transfer device 25a, and an outlet 28a is provided at the lower part. 29 has a secondary pulverization and recovery mechanism to which a screw conveyor 29a having substantially the same structure as 29 is connected. The screw conveyor 29a is connected to the product process E.

  The product process E has a product mechanism in which the take-out container 30 that receives the fine powder discharged from the screw conveyor 29a forms a centrifuge, and the opening on the side surface of the take-out container 30 has, for example, 100 to 300. A mesh filter 31 is provided. A centrifuge 32 is accommodated in the take-out container 30, and the centrifuge 32 is rotated by an electric motor 34 fixed to a frame base 33 that fixes the take-out container 30. The take-out container 30 has a structure surrounded by the cooling tank 35. Further, a third calcium carbonate supplier 13b and a third tank 14b for supplying a separating material such as calcium carbonate and carbon black to the takeout container 30 are provided.

  Accordingly, since the pulverized rubber chip G discharged from the screw conveyor 29a is accommodated in the take-out container 30, the third calcium carbonate feeder 13b supplies a separating material such as calcium carbonate or carbon black in the third tank 14b. When an appropriate amount is mixed in the take-out container 30 and the centrifuge is driven in this state, the mixture is sent to the filter 31 side, passes through this, and is sent from the take-out container 30 into the product box 36. As a result, a fine powder rubber that passes through a filter of 100 mesh or more is obtained as a product.

  The process and mechanism for mixing the separating material such as calcium carbonate or carbon black may be an indispensable matter in the product process and mechanism, but the coarse pulverization process and mechanism and the secondary fine pulverization process. And in the mechanism is not necessarily essential.

  The rubber composition of the present invention may be any powder as long as it contains powder rubber produced by the rubber chip pulverization method or apparatus. Preferably, the rubber powder obtained by the rubber chip pulverization method or apparatus is used. Among them, it is preferable that the powder rubber that has passed through the 100 mesh filter is 75% by weight or more, and more preferably, only the powder rubber that has passed through the 100 mesh filter is contained. Powdered rubber that has passed through a 100-mesh filter has very little possibility of becoming a fracture nucleus, and is particularly effective for suppressing a decrease in fracture strength.

  The content of the powder rubber in the rubber composition of the present invention is preferably 40 parts by weight or less, more preferably 1 to 30 parts by weight with respect to 100 parts by weight of the new rubber. When the content of the powder rubber exceeds 40 parts by weight, it is difficult to ensure desired fracture characteristics, depending on the degree of fine particle size.

  The new rubber used in the rubber composition of the present invention is not particularly limited, and various rubbers such as natural rubber and synthetic rubber similar to the rubber component in the powder rubber can be used. In addition, the rubber composition of the present invention can contain fillers such as carbon black, silica, alumina, aluminum hydroxide, etc. Various chemicals used in the above, for example, vulcanizing agents, vulcanization accelerators, process oils, anti-aging agents, anti-scorching agents, zinc white, stearic acid and the like can be appropriately contained.

  The rubber composition of the present invention is manufactured by blending the above-mentioned powdered rubber component and various compounding agents in a predetermined blending ratio with new rubber, and sequentially performing kneading, heating, extrusion, vulcanization, and the like. Can do.

  The kneading is preferably carried out by two-stage kneading in which the powder rubber according to the present invention is first kneaded with a new rubber, an anti-aging agent, etc., and then a vulcanizing agent, a vulcanization accelerator, etc. are added and kneaded again. is there. Other conditions are not particularly limited, and various conditions such as the input volume to the kneading apparatus, the rotational speed of the rotor, the ram pressure, the kneading temperature, the kneading time, the type of the kneading apparatus, etc. are appropriately determined according to the purpose. You can choose. Examples of the kneading apparatus include a Banbury mixer, an intermix, a kneader and the like that are usually used for kneading a rubber composition.

  The heating conditions are not particularly limited, and the conditions such as the heating temperature, the heating time, and the heating apparatus can be appropriately selected according to the purpose. As a heating apparatus, the roll machine etc. which are normally used for the heating of a rubber composition are mentioned, for example.

  Extrusion conditions are not particularly limited, and various conditions such as extrusion time, extrusion speed, extrusion apparatus, and extrusion temperature can be appropriately selected according to the purpose. As an extrusion apparatus, the extruder etc. which are normally used for extrusion of the rubber apparatus for tires are mentioned, for example. The extrusion temperature can be determined as appropriate.

  The vulcanization apparatus, method, conditions, etc. are not particularly limited and can be appropriately selected according to the purpose. Examples of the vulcanizing apparatus include a molding vulcanizer using a mold usually used for vulcanizing a rubber composition for tires. The extrusion temperature is usually about 100 to 190 ° C.

  In addition, the pneumatic tire of the present invention may be any tire as long as the rubber composition of the present invention is used as, for example, a tread rubber or the like, and the type of tire, its specific structure, material, etc. are particularly limited. Is not to be done. As an example of a pneumatic tire, although not shown, a pair of bead cores, a carcass connected in a toroidal shape between the bead cores, a belt for tightening a crown portion of the carcass, and a belt disposed on the belt And a tire having a tread rubber. The tire of the present invention may have a radial structure or a bias structure. Also, the production method is not particularly limited, and can be carried out according to conventional methods.

EXAMPLES Next, although this invention is demonstrated using an Example and a comparative example, this invention is not limited at all by the following Example.
Examples 1-6, Comparative Examples 1-6
As a waste rubber component, a rubber chip pulverization method (series of steps shown in FIG. 1 (coarse pulverization step A, pulverization recovery step B, secondary pulverization step C, secondary pulverization recovery step D and product step E)) Powder rubber A produced by the apparatus), powder rubber B including only the rubber that passed through a 100 mesh filter, commercially available recycled rubber, and commercially available powder rubber A, B (24 mesh product, 80 mesh product) Each prepared.

(1) Preparation of rubber composition For 100 parts by weight of styrene butadiene rubber (SBR) as a rubber component of the new material, the above waste rubber component and various compounding agents are blended in the blending ratios shown in Table 1 below. Each rubber composition was obtained by kneading using a 90 cc plast mill. The obtained rubber composition was subjected to pressure vulcanization at 160 ° C. for 13 minutes to obtain vulcanized rubber samples of respective comparative examples and examples. In addition, the used amounts of the waste rubber component and sulfur are as shown in Tables 2 and 3 below for the respective comparative examples and examples.

  The kneading was performed in two steps as follows. That is, first, in the first step, the waste rubber component was kneaded together with SBR, carbon black, softener, stearic acid, and anti-aging agent at a maximum temperature of 160 ° C. Subsequently, in the second step, the rubber obtained in the first step, zinc white, vulcanization accelerator A, vulcanization accelerator B, vulcanization accelerator C, and sulfur at a maximum temperature of 105 ° C. Kneaded. In addition, also when mix | blending only new rubber (Comparative example 1 of Table 2), it knead | mixed by the same method except not having added a waste rubber component.

(2) Measuring method For each vulcanized rubber sample of each comparative example and example obtained, the fracture characteristics (Tb) were measured by the following method to evaluate each rubber composition. In addition, the actual wear resistance of pneumatic tires using each rubber composition was also evaluated according to the following. The obtained results are shown in Tables 2 and 3 below.

(Evaluation method of fracture characteristics)
The breaking strength (Tb) was measured according to JIS K6301, and the value of Comparative Example 1 (containing no waste rubber component and using only new rubber) was set to 100, and displayed as an index. The larger the value, the better the fracture characteristics.

(Real wear resistance)
Each rubber composition was applied as a tread rubber to produce a pneumatic tire (PSR) for a passenger car having a tire size of 195 / 65R15, and the actual wear resistance was evaluated. The results were displayed as an index with the value of Comparative Example 1 being 100. The higher the number, the better the result.

＊１）合成ゴム：ＳＢＲ＃１５００（ＪＳＲ株式会社製）
＊２）カーボンブラック：シースト７ＨＭ（東海カーボン株式会社製）
＊３）軟化剤：アロマオイル
＊４）老化防止剤：ノクラック６Ｃ（大内新興化学工業株式会社製）
＊５）加硫促進剤Ａ：ノクセラーＤＭ−Ｐ（大内新興化学工業株式会社製）
＊６）加硫促進剤Ｂ：ノクセラーＮＳ−Ｐ（大内新興化学工業株式会社製）
＊７）加硫促進剤Ｃ：ノクセラーＤ（大内新興化学工業株式会社製）
＊８）硫黄：粉末硫黄

* 1) Synthetic rubber: SBR # 1500 (manufactured by JSR Corporation)
* 2) Carbon black: Seast 7HM (manufactured by Tokai Carbon Co., Ltd.)
* 3) Softener: Aroma oil * 4) Anti-aging agent: NOCRACK 6C (manufactured by Ouchi Shinsei Chemical Co., Ltd.)
* 5) Vulcanization accelerator A: Noxeller DM-P (Ouchi Shinsei Chemical Co., Ltd.)
* 6) Vulcanization accelerator B: Noxeller NS-P (Ouchi Shinsei Chemical Co., Ltd.)
* 7) Vulcanization accelerator C: Noxeller D (Ouchi Shinsei Chemical Co., Ltd.)
* 8) Sulfur: Powdered sulfur

＊９）市販再生ゴム：２４メッシュ品の粉ゴムより得られた再生ゴム（村岡ゴム工業株式会社製）
＊１０）市販粉ゴムＡ：２４メッシュ品（村岡ゴム工業株式会社製）
＊１１）市販粉ゴムＢ：８０メッシュ品（米国ＲＯＵＳＥ ＲＵＢＢＥＲ社製）

* 9) Commercial recycled rubber: Recycled rubber obtained from 24 mesh powdered rubber (Muraoka Rubber Industrial Co., Ltd.)
* 10) Commercial powder rubber A: 24 mesh product (Muraoka Rubber Industrial Co., Ltd.)
* 11) Commercial powdered rubber B: 80 mesh product (US ROUSE RUBBER)

  As can be seen from the results in Tables 2 and 3 above, the rubber compositions of Examples 1 to 6 containing powder rubber obtained by the rubber chip pulverization method (apparatus) according to the present invention are only new rubbers. Even when compared with the rubber composition of Comparative Example 1 used, it was confirmed that the rubber composition had excellent fracture characteristics that were inferior. In addition, it was confirmed that the tires of the examples using the rubber composition also had abrasion resistance comparable to that of the comparative examples.

1 is a schematic configuration diagram showing a rubber chip pulverization method and apparatus according to the present invention. It is a partially broken principal part enlarged view which takes out and shows a part in FIG. It is a top view which shows the diamond electrodeposition rotating drum and the diamond electrodeposition fixed blade in the rubber chip pulverizing apparatus according to the present invention. It is a side view which shows the diamond electrodeposition rotary drum and the diamond electrodeposition fixed blade in the rubber chip pulverization processing apparatus according to the present invention.

Explanation of symbols

A coarse pulverization process B fine pulverization recovery process C secondary pulverization process D secondary fine pulverization recovery process E product process 1 chip feeder 2 hopper 3 supply pipe 4 coarse pulverization mechanism 4a fine pulverization mechanism 5, 5a hopper 6, 6a Frame base 7, 7a Delivery pipe 8, 8a Crusher outer box 9, 9a Diamond electrodeposition rotary drum 10, 10a Motor 11, 11a, 29, 29a Screw conveyor 12, 12a Discharge pipe 13, 13a, 13b Calcium carbonate feeder 14 Tank 15 Shafts 16 and 21 Cooling pipes 17 and 17a Chain belts 18 and 18a Diamond electrodeposition fixed blade 19 Mounting plate 20 Arc surface 24 Air flow rate adjusting blower 25 Transfer device 26 Silo 27 Cyclone 28 Discharge port 30 Extraction container 31 Filter 32 Centrifugal Separator 33 Frame 34 Electric motor 35 Cooling tank 36 Product box

Claims (8)

A rubber composition containing powder rubber obtained by pulverizing rubber chips, wherein the powder rubber is
A coarse pulverization step in which the rubber chips are repeatedly coarsely pulverized and pulverized one or more times, a fine pulverization recovery step in which the coarsely pulverized and pulverized powder is collected by dust collection, and a secondary pulverization step in which the recovered fine powder is further pulverized. And a secondary pulverization and recovery step in which the finely pulverized product in the secondary pulverization step is sucked and recovered, and the secondary pulverized material that is not recovered is sent again to the secondary pulverization step, and finally pulverized And a step of removing the product through a filter of a predetermined mesh, and the coarse pulverization step and the secondary pulverization step are manufactured using a rubber chip fine pulverization method including pulverization with a diamond electrodeposition rotating drum and a diamond electrodeposition fixed blade A rubber composition characterized by being made.   The rubber composition according to claim 1, wherein the coarse pulverization step, the secondary pulverization step, and the product step include an additional step of mixing a separating material. A rubber composition containing powder rubber obtained by pulverizing rubber chips, wherein the powder rubber is
Coarse pulverization mechanism that pulverizes and pulverizes the rubber chip once or more, fine pulverization recovery mechanism that absorbs and collects the coarsely pulverized fine powder, and a secondary pulverization mechanism that further pulverizes the recovered fine powder A secondary pulverization and recovery mechanism for sucking and recovering the finely pulverized material by the secondary pulverization mechanism, and sending the secondary pulverized material not recovered again to the secondary pulverization mechanism; A rubber composition comprising: a powder rubber produced using a rubber chip pulverizing apparatus comprising: a product mechanism for taking out a product through a filter of a predetermined mesh.   The coarse pulverization mechanism and the secondary pulverization mechanism have a diamond electrodeposition rotating drum in which diamond grains are electrodeposited and fixed on a drum peripheral surface that can be driven and rotated, and an arc facing the drum peripheral surface with a predetermined gap. The rubber composition according to claim 3, further comprising: a diamond electrodepositing fixed blade having a surface and electrodepositing diamond grains on the arc surface.   The rubber composition according to claim 4, wherein each of the diamond electrodeposition rotating drum and the diamond electrodeposition stationary blade has a cooling means.   The rubber composition according to any one of claims 3 to 5, wherein the coarse pulverization mechanism, the secondary pulverization mechanism, and the product mechanism have an additional mechanism for mixing a separating material.   The rubber composition according to any one of claims 1 to 6, wherein the powder rubber contains 75% by weight or more of a powder that has passed through a 100 mesh filter.   A pneumatic tire using the rubber composition according to any one of claims 1 to 7.

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