JP2013155254A - Rubber-reinforcing material and rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber-reinforcing material for a rubber composition having good durability and considering environment, especially the rubber-reinforcing material capable of improving abrasion resistance and breaking strength of the rubber composition; and the rubber composition by using the same.SOLUTION: A rubber-reinforcing material is provided by containing chaff charcoal obtained by carbonizing chaff within 300 to 700°C range temperature under a non-oxygen atmosphere while agitating, as a main component, and also the rubber composition is provided by blending 1 to 50 pts.mass reinforcing agent based on 100 pts.mass rubber consisting of the blend of natural rubber with a diene-based rubber.

Description

  The present invention relates to high-quality rice husk charcoal used as a rubber reinforcement for tires, studless tire treads, tire sidewalls, belts, vibration proofs, brake pads, shoe soles, packings, hoses, electric wires, electrical parts, rubber for rolls, In particular, the rice husk charcoal is charcoal charcoal produced by carbonizing rice husk at a temperature in the range of 300 to 700 ° C. with stirring in an oxygen-free atmosphere.

In general, it is known that rubber is reinforced by adding carbon black, and fatigue resistance, wear resistance, and the like are greatly improved. In addition to carbon black, the reinforcing effect of so-called white fillers such as silica and calcium carbonate is also well known.
A rice husk is a material containing abundant carbon and silica as a rubber reinforcing material.

  In Japan, about 2 million tons of rice husks continue to be generated every year, of which about 40% are unused and difficult to dispose of. On the other hand, rice husks are concentrated in JA, etc., so the collection cost is low compared to other biomass species, and the biomass does not compete with food resources.

  The rice husk contains abundant carbon and silica, is hard, and has good wear characteristics. Therefore, it has been attempted to use it as a filler for polymers and rubber materials. (Non-Patent Document 1) However, in the rice husk state, even if pulverized into a powder form, it is difficult to reduce it to 50 μm or less, and thus the reinforcing effect was not recognized.

Therefore, the use of rice husk charcoal obtained by carbonizing rice husk was examined. (Non Patent Literature 2)
As a result of research, 1) Rice husk charcoal is treated with silane coupling to exert almost the same reinforcing effect as carbon black. 2) It is clear that the grain size of crushed rice husk charcoal is important for improving the breaking strength. Became.

  Against this background, a method has been proposed in which rice husk charcoal is added to tire rubber to improve wear resistance and rolling resistance, or to improve performance on ice of a studless tire. (Patent Documents 4 to 10)

  In addition, it is pointed out that the porous nature of the additive material is important for the reinforcement effect of rubber additives in order to increase the affinity between the rubber material and carbon and contribute to the formation of higher-order network structures. . (Patent Documents 1 to 3)

JP 2000-21113 A JP 2005-162865 A JP 2007-308594 A JP 2009-114251 A JP 2009-114252 A JP 2009-114253 A JP 2009-114254 A JP 2009-114255 A JP 2009-114257 A JP 2011-68784 A

Kenji Nakatsuji, Morio Seki, Nobuyoshi Kodama, Shinji Tagami, Susumu Aoyama: Research report of the Hiroshima Prefectural Industrial Technology Center / No. 7-30 (1994) Yoshihiro Yamashita, Kikio Kawabata, Nobuo Nagaoka: “Use of rice husk charcoal for rubber reinforcement” / Journal of the Japan Rubber Association, Vol. 73, No. 9 (2000)

  In the conventionally known rice husk carbonization method, there is a problem that it is difficult to efficiently and stably produce rice husk charcoal having high purity of carbon and silica, easy to pulverize, and developed porosity. .

  In Patent Documents 4 to 10, the rice husk charcoal used in the test is “bio charcoal” manufactured by Kansai Sangyo Co., Ltd., but this rice husk charcoal is manufactured in a low oxygen and non-uniform heating state, so it must maintain a certain quality. Therefore, it is difficult to stably produce porous rice husk charcoal. Such rice husk charcoal having a relatively small specific surface area has a weak affinity with the rubber material, and as a result, the durability of the rubber as a product tends to remain low.

  In addition, it is difficult to keep the composition of rice husk charcoal produced by such a manufacturing method, so it is difficult to reduce the particle size of the powder when pulverized rice husk charcoal and Variations will occur. When such rice husk charcoal powder is used as a rubber reinforcing material, a powder having a large particle diameter becomes the core of rupture, and the rupture strength of rubber as a product is lowered, which has been a major obstacle to commercialization.

  An object of the present invention is to provide a rubber reinforcing material for a rubber composition having good durability and considering the environment, and in particular, the wear resistance and breaking strength of the rubber composition containing the rubber reinforcing material. It is to provide a rubber reinforcing material that can be improved, and a rubber composition using the same.

  The present invention relates to a rubber reinforcing material and a rubber composition using the same, and particularly the rubber reinforcing material is rice husk charcoal. In particular, the rice husk charcoal is heated at 300 ° C. to 700 ° C. with stirring in an oxygen-free atmosphere. Carbonized at a temperature in the range of ° C.

  The invention according to claim 1 is characterized by comprising a rubber reinforcing material comprising, as a main component, rice husk charcoal obtained by carbonizing rice husk at a temperature in the range of 300 ° C. to 700 ° C. with stirring in an oxygen-free atmosphere. It is.

The invention according to claim 2 is characterized in that the rice husk charcoal is carbonized at a temperature in the range of 500 ° C. to 700 ° C., contains 60 to 70% by weight of carbon, and contains 30 to 40% by weight of silica, and has few impurities. The rubber reinforcing material according to claim 1, wherein the rubber reinforcing material is porous rice husk charcoal having a specific surface area of 200 m ² / g or more.

  The invention according to claim 3 is characterized in that the rice husk charcoal is carbonized at a temperature in the range of 500 ° C. to 700 ° C. and pulverized to an average particle size of 20 μm or less. It is a reinforcing material.

  The invention according to claim 4 is characterized in that 1 to 50 parts by mass of the rubber reinforcing material according to claim 1 is mixed with 100 parts by mass of rubber made of a blend of natural rubber and diene rubber. It is a rubber composition.

  According to the rubber reinforcing material according to the first to third aspects, it is possible to provide a rubber reinforcing material for a rubber composition which has good durability and is environmentally friendly.

  According to the rubber composition concerning Claim 4, the rubber composition which can improve wear resistance and breaking strength can be provided.

  According to the present invention, it is to provide a rubber reinforcing material for a rubber composition having good durability and considering the environment. Particularly, the rubber composition containing the rubber reinforcing material has wear resistance and breaking strength. A rubber reinforcing material that can be improved and a rubber composition using the same can be provided.

The comparison figure of the average particle diameter of each rice husk charcoal powder. A comparison of the BET specific surface area of each rice husk charcoal. The figure of various rice husk charcoal content and specific gravity of a rubber composition. The figure of various rice husk charcoal content and the hardness of a rubber composition. The figure of various rice husk charcoal contents and Mooney viscosity (100 degreeC) of a rubber composition. Figure of various rice husk charcoal content and tensile stress (100%) of rubber composition The figure of various rice husk charcoal contents and the tensile stress (200%) of a rubber composition. The figure of various rice husk charcoal contents and the tensile stress (300%) of a rubber composition. Diagram of various rice husk charcoal content and breaking strength per unit area of rubber composition The figure of the maximum elongation of various rice husk charcoal content and a rubber composition. The block diagram of one example of the carbonization apparatus which produces the rice husk charcoal which is a rubber reinforcement of this invention. The SEM photograph of the rubber composition which added 20 weight part of SUMIX rice husk charcoal of carbonization temperature 700 degreeC. (500 times magnification) The SEM photograph of the rubber composition which added 20 weight part of SUMIX rice husk charcoal of carbonization temperature 500 degreeC. (500 times magnification) The SEM photograph of the rubber composition which added 20 weight part of SUMIX rice husk charcoal of carbonization temperature 300 degreeC. (500 times magnification) SEM photograph of a rubber composition to which 20 parts by weight of “bio charcoal” manufactured by Kansai Sangyo Co., Ltd. is added. (500 times magnification) For various chaff charcoal showed carbon (C), silica _(Si0 2), other content Fig.

In the present invention, the rice husk, which is a material, is carbonized while stirring in a rotary kiln so as to be thermally decomposed uniformly and homogeneously in an oxygen-free atmosphere, thereby providing a preferable feature as a rubber reinforcing material. Provide rice husk charcoal.
Specifically, because the ratio of carbon and silica contained in rice husk charcoal is constant, and because of its high purity, it is excellent in pulverization, and because of its large specific surface area, it has excellent compatibility with rubber materials. Rubber products using this as a reinforcing material have high breaking strength and excellent durability.
In addition, since the rice husk is a natural material, for example, when used in a tire, it is harmless even if it is worn and released into the environment, and is a material that is friendly to the environment.

  Charcoal husk charcoal, which is a carbide used in the rubber reinforcing material of the present invention, is characterized in that it is carbonized in a carbonization apparatus that is carbonized while stirring in an oxygen-free atmosphere. As the carbonization apparatus to be used, any form may be used as long as the carbonized object is carbonized in an oxygen-free atmosphere.

As an example of the carbonization apparatus, FIG. 11 shows a configuration diagram of an example of the carbonization apparatus for carbonizing the rice husk of the present invention. As shown in FIG. 11, the carbonization apparatus (reduction carbonization processing apparatus) used in the present invention includes a rotating kiln 2 in which a spiral blade and a stirring blade 1 are arranged, and an interior of the one kiln 2. Combustion chamber 3 that stores the organic matter, etc., including the input waste, in an organic material etc. while indirectly heating in a reduced state in an oxygen-free atmosphere and supplies heat to the entire interior of one kiln 2, and the combustion chamber 3 A heating unit 4 such as a burner, a drying unit 2a having an area set inside the kiln 2 so as to evaporate water contained in the organic matter and the like introduced into the kiln 2 by indirect heating of the combustion chamber 3, and a drying unit A carbonized portion 2b having an area set inside the kiln 2 so as to be carbonized by indirectly heating and decomposing the organic matter dried by 2a.
This apparatus is referred to as a reduction sterilization carbonization machine SUMIX (manufactured by Gaia Environmental Technology Laboratory Co., Ltd.), and the carbide produced by this apparatus is hereinafter referred to as SUMIX charcoal. The rice husk charcoal is called SUMIX rice husk charcoal.

  Examples of the rubber reinforcing material and rubber composition of the present invention will be described below.

（籾殻炭）
・（株）ガイア環境技術研究所社製 還元滅菌炭化加工機「SUMIX」による「SUMIX籾殻炭（炭化温度：300℃、500℃、700℃）」
・関西産業（株）社製 「バイオ炭」

ゴム補強材としての籾殻炭は、YAMATO社製ボールミルを用いて、12時間粉砕し、それぞれの粒径をセイシン企業社製レーザー回折散乱式粒度分布測定器「LMS-2000e」を用いて測定した。粉砕した各籾殻炭粉の平均粒径を図１に示す。

尚、図１にて、「S300」は「SUMIX」により炭化温度300℃で製造したもの、「S500」は「SUMIX」により炭化温度500℃で製造したもの、「S700」は「SUMIX」により炭化温度700℃で製造したもの、「KBC」は関西産業社製バイオ炭を示す。（以下の試験グラフでも同様） (Rubber composition)
Hereinafter, rice husk charcoal and various chemicals used in the comparative experiment are described.
(Basic composition of rubber composition)
Table 1 shows the basic composition of rubber raw materials.

(Rice husk charcoal)
・ "SUMIX rice husk charcoal (carbonization temperature: 300 ℃, 500 ℃, 700 ℃)" by reduction sterilization carbonization machine "SUMIX" manufactured by Gaia Environmental Technology Laboratory Co., Ltd.
・ "Bio-charcoal" manufactured by Kansai Sangyo Co., Ltd.

Rice husk charcoal as a rubber reinforcing material was pulverized for 12 hours using a ball mill manufactured by YAMATO, and each particle size was measured using a laser diffraction scattering type particle size distribution analyzer “LMS-2000e” manufactured by Seishin Enterprise Co., Ltd. The average particle diameter of each crushed rice husk charcoal powder is shown in FIG.

In Fig. 1, "S300" is manufactured by "SUMIX" at a carbonization temperature of 300 ° C, "S500" is manufactured by "SUMIX" at a carbonization temperature of 500 ° C, and "S700" is carbonized by "SUMIX". "KBC" manufactured at a temperature of 700 ° C indicates bio-charcoal produced by Kansai Sangyo Co., Ltd. (The same applies to the following test graphs)

Fig. 2 shows the BET specific surface areas of these rice husk charcoal.
These rice husk charcoal powders were blended in an amount of 1 to 50 parts by mass with respect to the raw materials shown in Table 1 to prepare rubber compositions.

(Comparative experiment)
The following comparative experiment was conducted on the rubber composition prepared as described above.
・ Hardness: Hardness meter ELASTLON ESA (DUROMETER
A)
・ Specific gravity: Hydrometer ALFAMIRAGE MD-3005
・ Tensile stress: Tensile testing machine MONTECH TECH-500
-Breaking strength and elongation: Tensile tester MONTECH TECH-500
・ Mooney viscosity: Mooney viscometer

(Test results)
(specific gravity)
FIG. 3 shows the specific gravity of each rubber composition. The horizontal axis represents the content (parts by mass) of rice husk charcoal as a reinforcing material, and the content of 0 indicates the value of a comparative sample that does not contain rice husk charcoal. In addition, the type of rice husk charcoal used is distinguished by line type. (The same applies to the following test graphs)
From FIG. 3, it can be seen that when SUMIX rice husk charcoal carbonized at 300 to 700 ° C. is blended, the specific gravity is small at the same charcoal content as compared with the case where biochar is blended. For example, this is advantageous in terms of fuel consumption when used as a tire. Moreover, when used for a machine belt or the like, the burden on power is reduced. In addition, when used for anti-vibration rubber, shoe soles, hoses, etc., in many cases, it is presumed to be a preferable property.

(hardness)
FIG. 4 shows the hardness of each rubber composition.
From FIG. 4, it can be seen that the case where SUMIX rice husk charcoal is blended has lower hardness at the same charcoal content than the case where biochar is blended. As for the hardness of rubber, the required properties differ depending on the application, so it is generally impossible to judge whether it is good or bad.

(Mooney viscosity)
FIG. 5 shows the Mooney viscosity of each rubber composition.
FIG. 5 shows that the Mooney viscosity tends to be higher when the SUMIX rice husk charcoal is blended than when the bio charcoal is blended. Since Mooney viscosity is an index related to the processing characteristics of a rubber material, the required properties differ depending on the application, and therefore it cannot be judged whether it is good or bad. However, when SUMIX rice husk charcoal is blended, the response to the content is more stable than when biochar is blended, which is a preferable property in material design.

(Tensile stress)
The value of the tensile stress by a tensile tester is shown in FIGS. Fig. 6 shows the stress per unit area applied to both ends of the sample when the sample is pulled to 100%, that is, double the length. Figs. 7 and 8 show the stress when the sample is pulled to the length of 200% and 300%. Show.
The value of the tensile stress is also different depending on the application to be used, so it is generally impossible to judge whether it is good or bad. However, in the SUMIX rice husk charcoal compound, there is a tendency for tensile stress to increase as the carbonization temperature rises, indicating that it is possible to selectively produce a reinforcing material having properties suitable for the rubber material required by the carbonization temperature. ing. In addition, when SUMIX rice husk charcoal is blended as a whole, the response to the content is more stable than when biochar is blended, which is a favorable property in material design.

(Breaking strength)
FIG. 9 shows the breaking strength per unit area, and FIG. 10 shows the elongation of the sample at the time of breaking, that is, the maximum elongation.
Overall, it can be seen that the samples using SUMIX rice husk charcoal with carbonization temperatures of 500 ° C. and 700 ° C. are clearly superior in breaking strength compared to 300 ° C. and bio charcoal. Moreover, in the case of the same 500 degreeC and 700 degreeC, the tendency for breaking strength to increase compared with control was recognized by content of 1-2 mass parts. Increasing the breaking strength of a rubber material is a favorable property for almost all applications.
Regarding the maximum elongation, the response to the content is more stable in the case where SUMIX rice husk charcoal is blended as compared with the case where biochar is blended, which is a preferable property in material design.

FIG. 12 is an SEM photograph of a rubber composition to which 20 parts by weight of SUMIX rice husk charcoal having a carbonization temperature of 700 ° C. is added. (Magnification 500 times).
FIG. 13 is an SEM photograph of a rubber composition to which 20 parts by weight of SUMIX rice husk charcoal having a carbonization temperature of 500 ° C. is added. (Magnification 500 times).
FIG. 14 is an SEM photograph of a rubber composition to which 20 parts by weight of SUMIX rice husk charcoal having a carbonization temperature of 300 ° C. is added. (Magnification 500 times).
FIG. 15 is an SEM photograph of a rubber composition to which 20 parts by weight of “bio charcoal” manufactured by Kansai Sangyo Co., Ltd. is added. (Magnification 500 times).
12 to 15, the grains in the photographs are the particles of rice husk charcoal powder.
The particles of rice husk charcoal powder are fine in the order of FIGS.

In the case of “bio charcoal” manufactured by Kansai Sangyo Co., Ltd. in FIG. 15, the average particle size is smaller than that of SUMIX rice husk charcoal with a carbonization temperature of 300 ° C. As a result, coarse particles are mixed.
In the rupture test, “bio charcoal” manufactured by Kansai Sangyo Co., Ltd. breaks with these coarse particles serving as nuclei, resulting in a rupture strength as shown in FIG.

FIG. 16 is a diagram showing carbon (C), silica (SiO ₂ ), and other contents of various rice husk charcoal. SUMIX rice husk charcoal having carbonization temperatures of 500 ° C. and 700 ° C. contains 60 to 70% by weight of carbon and 30 to 40% by weight of silica, and has few impurities.

  According to the rubber reinforcing material of the present invention, it is possible to provide a rubber reinforcing material for a rubber composition that has good durability and is environmentally friendly. Particularly, the rubber composition using the rubber reinforcing material has an abrasion resistance. As a range of applications, tires, studless tire treads, tire sidewalls, belts, anti-vibration, brake pads, shoe soles, packings, hoses, electric wires, electrical components, rubber for rolls It can be applied to a wide range.

DESCRIPTION OF SYMBOLS 2 ... Kiln 2a Drying part 2b Carbonization part 2d Heat storage part 2c Internal space 2in Inlet 2out Outlet 3 ... Combustion chamber 3a ... Exhaust pipe 4 ... Heat source 5 ... Piping part 6 ... Cooling part 7 ... Deodorizing part 8 ... Dry distillation gas recovery part 9 ... Auxiliary heating source 10 ... Steam smoke path 11 ... Oilification section 12 ... Water distribution pipe 13 ... Fan 14 ... Hopper 15 ... Raw material supply pipe 16 ... Supply screw 17 ... Second discharge pipe 18 ... Cooling device 19 ... Connection pipe (downstream side) Exhaust pipe)
19a Downstream exhaust pipe upper pipe
19b Downstream exhaust pipe
20 ... Conveying screw 21 ... Conveying screw 22 ... Steam vent pipe (upstream exhaust gas pipe)
22a Upper side exhaust pipe upper pipe
22b Upstream exhaust pipe lower pipe
23 Chimney part 24 Circulation pipe 25 Degassing pipe 30 Connection part 60 Collection part P Input material Q Carbonized material

Claims (4)

A rubber reinforcing material comprising, as a main component, rice husk charcoal obtained by carbonizing rice husk at a temperature in a range of 300 ° C. to 700 ° C. with stirring in an oxygen-free atmosphere. The rice husk charcoal is carbonized at a temperature in the range of 500 ° C. to 700 ° C., contains 60 to 70% by weight of carbon and 30 to 40% by weight of silica, and has a specific surface area of 200 m ² / g or more. The rubber reinforcing material according to claim 1, wherein the rubber reinforcing material is porous rice husk charcoal. The rubber reinforcing material according to claim 1 or 2, wherein the rice husk charcoal is carbonized at a temperature in the range of 500 ° C to 700 ° C and pulverized to an average particle size of 20 µm or less. A rubber composition comprising 1 to 50 parts by mass of the rubber reinforcing material according to claim 1 mixed with 100 parts by mass of rubber comprising a blend of natural rubber and diene rubber.

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