JP5632661B2 - Carbon material for rubber reinforcement and method for producing the same - Google Patents

Description

  The present invention relates to a carbon material for rubber reinforcement and a method for producing the carbon material for rubber reinforcement, and more particularly to a method for producing a carbon material for rubber reinforcement capable of effectively using polymer waste.

  Conventionally, various polymer materials such as rubber materials and resin materials have been industrialized for the purpose of developing functional materials. On the other hand, the development of the polymer industry has led to mass production of general-purpose materials, mass production of general-purpose materials. Consuming and the disposal of polymer waste has become an important issue to be solved immediately. In order to solve this problem, technological progress such as reuse and recycling of polymer materials is essential. For example, tires made of rubber materials have been mass-produced and consumed in large quantities as automobile essential parts along with the development of motorization, and the number of used tires has become enormous. In particular, the recovery of useful materials has become a major issue. For example, in Japanese Patent Laid-Open No. 8-27394 (Patent Document 1), organic waste is partially combusted and gasified in a mixed gas of oxygen-containing gas and water vapor with an oxygen equivalent ratio of 1 or less, and the resulting combustible material is obtained. A carbon black characterized by partially burning a gas at a temperature of 1000 ° C. or higher in an oxygen-deficient state with a theoretical oxygen amount or less, and rapidly quenching the resulting partial combustion gas of 1000 ° C. or higher to 700 ° C. or lower in an inert atmosphere A manufacturing method is disclosed.

JP-A-8-27394

  However, the organic waste usually contains substances other than hydrocarbons, and carbides obtained by incomplete combustion or thermal decomposition of these are obtained by incomplete combustion or thermal decomposition of hydrocarbons. Unlike carbides (ie, carbon black in the original sense), the rubber composition cannot be sufficiently reinforced when compounded with rubber, and thus recovers the inherent value from polymer waste. However, there is still room for improvement in terms of effective use.

  Accordingly, an object of the present invention is to provide a method for producing a carbon material for reinforcing rubber capable of solving the above-described problems of the prior art and capable of effectively using polymer waste. Another object of the present invention is to provide a carbon material for rubber reinforcement that can sufficiently exert a reinforcing effect even if it is blended with a rubber component, even though it contains carbides obtained from polymer waste. There is to do.

  As a result of intensive investigations to achieve the above-mentioned object, the present inventors have mixed carbon carbide obtained by thermal decomposition or incomplete combustion of polymer-based waste with carbon black. Despite the fact that it contains carbides derived from polymer waste, which is said to be low, it has been found that a carbon material for rubber reinforcement can be obtained that can sufficiently exert its reinforcing effect even if blended with a rubber component. The present invention has been completed.

That is, the manufacturing method of the rubber-reinforcing carbon material of the present invention, viewed contains a carbide (A) obtained by thermal decomposition or incomplete combustion of polymer waste, a step of mixing the carbon black (B), The carbide (A) and the carbon black (B) are granulated independently and then mixed .
In this case, the tensile stress of the rubber composition can be improved as compared to a carbon material for rubber reinforcement obtained by granulation after mixing the carbide (A) and the carbon black (B).

  In the method for producing a carbon material for reinforcing rubber of the present invention, the mixing mass ratio (A / B) of the carbide (A) and the carbon black (B) is within a range of 1/99 to 50/50. Is preferable, and it is still more preferable to be within the range of 10/90 to 50/50. In this case, rubber properties equivalent to those of pure carbon black can be ensured despite the inclusion of carbides obtained from polymer waste. In the mixing mass ratio (A / B) of the carbide (A) and the carbon black (B), when the ratio of the carbide (A) is less than 1% by mass, the carbon black (B) alone is blended. On the contrary, when the ratio of the carbide (A) exceeds 50%, the difference from the rubber physical properties when blended with carbon black (B) alone may decrease by 5% or more, which is not preferable. .

According to the present invention, a carbide obtained by pyrolysis or incomplete combustion of polymer waste is mixed with carbon black , where the carbide (A) and the carbon black (B) are granulated independently. by mixing after, despite contains carbides obtained from polymer waste, also reinforcing effect by compounding the rubber component provides a rubber-reinforcing carbon material can be sufficiently exhibited Can do. Therefore, it is possible to effectively use the polymer waste.

It is the schematic of the thermal decomposition apparatus used for manufacture of a carbide | carbonized_material (A).

  The present invention is described in detail below. The method for producing a carbon material for reinforcing rubber of the present invention comprises a step of mixing a carbon black (B) with a carbide (A) obtained by thermal decomposition or incomplete combustion of a polymer waste. To do. Since the carbon material obtained by the production method of the present invention contains carbon black (B) together with the carbide (A) obtained from the polymer waste, it reduces the physical properties of the rubber and has a reinforcing effect on the rubber. You can play well. Therefore, in order to reliably use the carbide obtained by thermal decomposition or incomplete combustion of the polymer waste as a rubber reinforcing material, it is necessary to mix it with carbon black. In addition, for mixing the carbide (A) and the carbon black (B), for example, a mixer such as a container rotation type, a mechanical stirring type, or an air flow type is used.

  In the method for producing a carbon material for rubber reinforcement of the present invention, by controlling the mixing ratio of the carbide (A) and the carbon black (B), the vulcanization characteristics, the reinforcing property and the like are compared with those when pure carbon black is blended alone. Even if it is, the same physical property can be ensured. When the present inventors tried to optimize the mixing ratio of the carbide (A) and the carbon black (B), the above-mentioned carbide (A) and the carbon black were improved from the viewpoint of improving the reinforcing effect and reducing other physical properties of the rubber. The mixing mass ratio (A / B) with (B) is preferably in the range of 1/99 to 50/50, more preferably in the range of 10/90 to 50/50.

  Moreover, since the carbon material for rubber reinforcement obtained by the production method of the present invention is blended in a rubber composition, it is usually used after granulation in the same manner as carbon black. Here, when the present inventors further examined, it discovered that the influence which it has on the rubber physical property of the carbon material for rubber reinforcement obtained as a result changes with the order of a granulation process and a mixing process. Specifically, the carbide (A) and the carbon black (B) are granulated independently and then mixed, that is, by performing the granulation step before the mixing step, The tensile stress of the rubber composition can be improved compared to a carbon material for rubber reinforcement obtained by performing a granulation step later. In addition, as a granulation method, both the wet method which granulates using water or another liquid, and the dry method which does not use a medium are employable. In addition, as a granulator and a dryer, what is normally used for the granulation and drying of carbon black can be used, As a specific example, granulators, such as a rolling granulator, and rotary drying And dryers such as a dryer, a flow dryer, a fluid dryer, and a tunnel dryer.

  In the method for producing a carbon material for rubber reinforcement of the present invention, the carbide (A) is a carbide obtained by thermal decomposition or incomplete combustion of a polymer waste, and a pyrolysis reaction using the polymer waste as a raw material. Alternatively, it refers to a solid that is generated and left after the gas body and liquid component in the raw material are released by incomplete combustion reaction, and may contain an inorganic substance as ash. The thermal decomposition or incomplete combustion of the polymer waste is not particularly limited, and various thermal decomposition methods and incomplete combustion methods can be employed. For example, polymer waste can be pyrolyzed by containing polymer waste in a pyrolysis furnace and supplying heated oxygen-free gas into the pyrolysis furnace. Here, the oxygen-free gas is a gas body other than oxygen and oxide, and examples thereof include an inert gas such as nitrogen, argon, and helium, and a combustible gas such as hydrogen, methane, and propane. The pyrolysis furnace is not particularly limited, and for example, a pot-type pyrolysis furnace, a fluidized-bed pyrolysis furnace, a kiln-type pyrolysis furnace, or the like is used.

  The polymer waste mainly refers to organic waste, and specifically, rubber material waste such as tire waste (eg, spew, buff powder, 4-32 divided tires), carbonization waste, and the like. Polymer materials obtained by (co) polymerization reaction of hydrogen monomers, such as polyethylene, polypropylene, styrene-butadiene copolymers, etc. Copolymers of hydrocarbon monomers with other monomers, such as ethylene-vinyl acetate copolymers And (co) polymers of halogen derivatives of hydrocarbon monomers, for example, resin material waste such as polyvinyl chloride. Further, steel cords, wires, and the like are mixed with carbides in the residue after the tire waste is pyrolyzed.

  In the thermal decomposition or incomplete combustion of the polymer waste, it is preferable to control the treatment temperature in the range of 300 to 600 ° C. When the treatment temperature is within the specified range, the polymer waste can be stably and continuously pyrolyzed or incompletely combusted. If the treatment temperature is less than 300 ° C., the thermal decomposition reaction or incomplete combustion reaction does not proceed sufficiently, which may generate carbides in which components to be decomposed are not completely removed, while 600 ° C. If exceeded, undesirable secondary reactions and activation reactions may occur between the generated carbide and other components present in the reaction system, and there is a risk of generating a carbide that is porous and may adversely affect the reinforcing effect on the rubber. is there.

  Carbide (A) obtained by thermal decomposition or incomplete combustion of the polymer waste, for example, when tire waste is used, because it is mixed with steel cords and wires that are aggregates of tires, It is preferable to use it separated from a steel cord or wire using a magnet, a sieve or the like. Further, as described above, the carbide (A) is granulated in the course of manufacturing the rubber reinforcing carbide, but the carbide obtained by thermal decomposition or incomplete combustion of the polymer waste is carbonized. It consists of an agglomerated part and a powdery part aggregated in the process. Therefore, for example, it is preferable to finely break the carbide by a pulverization process using a pulverizer or the like.

  In the method for producing a carbon material for reinforcing rubber according to the present invention, carbon black (B) is an approximately pure element obtained by thermal decomposition or incomplete combustion of hydrocarbons performed under conditions of controlling strict temperature and various parameters. Carbon. Here, the method for producing carbon black (B) is not particularly limited, and usual carbon black production methods such as a thermal decomposition method and an incomplete combustion method can be employed. In addition, as a raw material for carbon black (B), gas or liquid hydrocarbon is usually used, and petroleum heavy oil obtained at the time of catalytic cracking to gasoline or ethylene, or creo associated with coke production by dry distillation of coal. Heavy coal oil such as sort oil is mainly used.

  In the method for producing a carbon material for reinforcing rubber of the present invention, when the carbide (A) and the carbon black (B) are granulated independently and mixed, the carbon black (B) Commercially available carbon black can be used. Moreover, the carbon material for rubber reinforcement obtained by performing the granulation step before the mixing step can improve the tensile stress of the rubber composition in addition to the reinforcing effect, and can be used as a rubber composition for a tire member such as a tread surface. Is preferred. Therefore, from the viewpoint of application to such a tire member, as the carbon black (B), GPF, FEF, HAF-LS, HAF, HAF-HS, ISAF, and SAF grades are particularly preferable.

  Next, the rubber reinforcing carbon material of the present invention will be described in detail. The carbon material for rubber reinforcement of the present invention comprises a carbide (A) and carbon black (B) obtained by thermal decomposition or incomplete combustion of polymer waste, and can be manufactured by the above-described manufacturing method. . In addition, the carbon material for rubber reinforcement of the present invention can sufficiently exhibit the reinforcing effect even if it is blended with a rubber component, even though it contains carbides obtained from polymer waste.

  As described above, by controlling the mixing ratio of carbide (A) and carbon black (B), the reinforcing effect on rubber is improved, and other rubber properties are secured to the same extent as in the case of pure carbon black. Can do. Therefore, in the rubber material for reinforcing rubber of the present invention, the mass ratio (A / B) of the carbide (A) to the carbon black (B) is preferably in the range of 1/99 to 50/50. More preferably, it is within the range of 10/90 to 50/50.

  Also, the carbon material for rubber reinforcement of the present invention is as fine as the particle size of the rubber reinforcing filler from the viewpoint of being used in place of a rubber reinforcing filler such as carbon black blended in the rubber composition. The average particle size is preferably 50 μm or less, and more preferably 10 μm or less.

  Next, a rubber composition obtained by blending the carbon material for rubber reinforcement of the present invention and a tire using the rubber composition will be described in detail. The rubber composition is characterized by blending the carbon material described above. The rubber composition includes, for example, the above-mentioned carbon material for rubber reinforcement and a rubber component, as well as compounding agents commonly used in the rubber industry, such as fillers, softeners, silane coupling agents, stearic acid, anti-aging An agent, zinc white, vulcanization accelerator, vulcanizing agent and the like can be appropriately blended depending on the purpose. As these compounding agents, commercially available products can be suitably used. The rubber composition can be prepared by blending the rubber component with various compounding agents appropriately selected as necessary together with the rubber reinforcing carbon material, kneading, heating, extruding, and the like. it can.

  The rubber component is not particularly limited. In addition to natural rubber (NR), polyisoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR), ethylene-propylene-diene rubber. (EPDM), chloroprene rubber (CR), halogenated butyl rubber, acrylonitrile-butadiene rubber (NBR), and other synthetic rubbers can be used. These rubber components may be used alone or in combination. You may blend and use the above.

  On the other hand, the tire is characterized by using the rubber composition described above, and despite the use of carbides obtained from polymer waste, the physical properties of the tire while ensuring sufficient reinforcement Reduction can be reduced. The tire is not particularly limited except that the rubber composition described above is used, and can be manufactured according to a conventional method. Moreover, as gas with which this tire is filled, inert gas, such as nitrogen, argon, helium other than normal or the air which adjusted oxygen partial pressure, can be used.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

(Manufacture of carbide (A))
Carbides were recovered from the waste truck tires using the thermal decomposition apparatus shown in FIG.
The pyrolysis apparatus shown in FIG. 1 is a thermal decomposition apparatus suitable for the production of carbide (A), and contains a heat exchanger 1 for heating oxygen-free gas and a polymer waste 6 inside. Pyrolysis furnace 2 and external heating means 8 for heating the pyrolysis furnace 2 from the outside, and the polymer waste 6 is pyrolyzed by directly contacting the oxygen-free gas heated by the heat exchanger 1 The cracking device 7 for generating pyrolysis gas, the pyrolysis gas generated in the cracking device 7 is cooled, the oil recovery device 5 for recovering the condensed oil, and the oil recovery device 5 A circulation path 4 for supplying the recovered residual gas as an oxygen-free gas to the heat exchanger 1 and an oxygen-free gas supply source 3 for supplying the heat exchanger 1 with the oxygen-free gas are provided. Further, the pyrolysis apparatus shown in FIG. 1 includes a flow meter 9, a damper in a pipe connecting the oxygen-free gas supply source 3 and the heat exchanger 1 in order to supply oxygen-free gas from the oxygen-free gas supply source 3. 10 and a blower 11, a flow meter 9, a damper 10, a blower 11, and a hot stove in a circulation path 4 for circulating the residual gas recovered by the oil content recovery device 5 as an oxygen-free gas to the heat exchanger 1. 14. Further, the oil content recovery device 5 shown in FIG. 1 includes a plurality of dry distillation towers 12a and 12b in order to divide the recovered oil content according to the boiling point thereof. Here, each of the carbonization towers 12 is recovered through a pipe at the lower part thereof. It is connected to the tank 13 and can store the recovered oil. Furthermore, in the thermal decomposition apparatus shown in FIG. 1, surplus gas can be released into the atmosphere after being treated by the exhaust gas treatment device 16 via the exhaust fan 15.

Specifically, after putting about 100 kg of waste truck tire cut products (polymer waste 6) into the pyrolysis furnace 2 (capacity 0.5 m ³ ) and replacing the pyrolysis furnace 2 with nitrogen gas, While circulating the nitrogen gas in the thermal decomposition apparatus, the gas temperature was raised to about 500 ° C. by the heat exchanger 1 and this temperature was maintained. The gas flow rate of nitrogen gas introduced into the pyrolysis furnace 2 is set to 0.005m ³ / s [ntp], controlled in the range of ^{0.0045m 3 /s[ntp]~0.0055m 3 / s [ntp} ] However, the oxygen concentration in the pyrolyzer system was controlled within a range of 1% by volume or less. Here, a zirconia oxygen sensor was used to measure the oxygen concentration in the thermal decomposition apparatus. One hour after the start of heating by the heat exchanger 1, the pyrolysis gas began to be accumulated in the dry distillation column 12a, and the distillation stopped about 4 hours after the start of heating by the heat exchanger 1. Stopping the distillation showed that the thermal decomposition reaction was completed, and the heat exchanger 1 was stopped and the system was left to cool for about 12 hours. Thereafter, the carbide was taken out from the pyrolysis furnace 2. Since the carbide includes a steel cord as a tire material, excess tire material was removed with a magnetic separator. Carbide from which excess tire material has been removed is pulverized into fine powder with a particle size of 1 mm or less with a hammer-type pulverizer, and this pulverized product is classified with an air classifier having rotating blades, resulting in a particle size of 50 μm. The above coarse powder was removed, and a fine carbide (A) having a particle size of 10 μm or less was obtained using a classifier.
As shown in Table 1, the fine carbide for rubber compounding had a characteristic of a nitrogen adsorption specific surface area (N ₂ SA) of 81.6 m ² / g and a DBP absorption of 85.2 ml / 100 g.

<Example 1>
(Manufacture of carbon materials for rubber reinforcement)
Using the soft carbon black manufacturing apparatus disclosed in JP-A-61-34071 (Applicant: Asahi Carbon Co., Ltd.), the manufacturing conditions described in claim 1 of JP-A-61-34071 are applied. Thus, GPF grade carbon black was produced. The production yield of GPF grade carbon black under the above production conditions was 150 kg / hr. This GPF grade carbon black and the fine carbide for rubber compounding obtained in the above production example are each separately granulated with a pin type granulator, and then the obtained wet granulated product is used in the usual process for producing carbon black. It was dried by a drying process according to the method. Next, 500 g of each of these two granulated products was put into a V-type mixer and mixed by rotating at 20 rpm for 5 minutes to obtain a carbon material I for rubber reinforcement.

<Example 2>
A rubber reinforcing carbide II is obtained in the same manner as in Example 1 except that the mixing mass ratio (A / B) of the carbide (A) and the carbon black (B) is changed to 20/80 (200 g of carbide, 800 g of GPF). It was.

<Example 3>
A rubber reinforcing carbide III is obtained in the same manner as in Example 1 except that the mixing mass ratio (A / B) of the carbide (A) and the carbon black (B) is changed to 10/90 (100 g of carbide, 900 g of GPF). It was.

<Example 4>
Carbide reinforcing carbide IV is obtained in the same manner as in Example 1 except that the mixing mass ratio (A / B) of carbide (A) and carbon black (B) is changed to 60/40 (carbide 600 g, GPF 400 g). It was.

<Example 5>
In the manufacturing process in the GPF class carbon black manufacturing process, 500 kg of the fine rubber compounding material for rubber blending obtained in the above manufacturing example is added to the GPF class by using a quantitative feeder from the powder supply port in the pin type granulator. It added to carbon black powder, both were mixed, detecting the torque of the rotating shaft of a granulator, and controlling the amount of water to add, and the flow forming process was implemented. The resulting mixed wet granulated product was transferred to a drying step in accordance with a conventional method for producing carbon black and dried to obtain a rubber material V for reinforcing rubber.

Dibutyl phthalate (DBP) was used for rubber reinforcing carbon materials I to V obtained from Examples 1 to 5, fine carbide for rubber compounding, and GPF grade carbon black [manufactured by Asahi Carbon Co., Ltd., trade name: Asahi # 55]. ) Oil absorption and nitrogen adsorption specific surface area (N ₂ SA) were measured by the following methods. The results are shown in Table 1. From the results obtained, the carbon material for rubber reinforcement has a structure comparable to that of GPF grade carbon black, but has a much larger specific surface area (small particle diameter). I understand that.

(1) Nitrogen adsorption specific surface area (N ₂ SA)
The nitrogen adsorption specific surface area (N ₂ SA) was measured according to JIS K 6217-2: 2001.
(2) Dibutyl phthalate (DBP) oil absorption The dibutyl phthalate (DBP) oil absorption was measured according to JIS K 6217-4: 2008.

  Rubber compositions having the compounding formulations shown in Table 2 by using carbon materials I to V for rubber reinforcement of Examples 1 to 5 and GPF class carbon black [manufactured by Asahi Carbon Co., Ltd., trade name: Asahi # 55] as a control. The rubber properties of the rubber composition before and after vulcanization were measured by the following method. The results are shown in Table 3.

* 1 Oil-extended rubber, oil-extended with 27.3 parts by mass of aroma oil for 100 parts by mass of rubber component, manufactured by JSR Corporation, product name: SBR 1723.
* 2 Product name: BROMOBUTYL 2255, manufactured by JSR Corporation.
* 3 Each sample shown in Table 1 was used.
* 4 Product name: Santoflex 6PPD, manufactured by Flexis.
* 5 Ouchi Shinsei Chemical Industry Co., Ltd., trade name: Noxeller DM-P.
* 6 Product name: NOCRACK manufactured by Ouchi Shinsei Chemical Co., Ltd.
* 7 Ouchi Shinsei Chemical Co., Ltd., trade name: Noxeller
* 8 Product name: NOXELLER NS.

(3) Rubber properties when not vulcanized (a) Mooney viscosity Measured Mooney viscosity [ML _{1 + 4} (130 ° C)] at 130 ° C using Mooney viscometer according to JIS K6300-1: 2001 did. The rubber composition containing the GPF grade carbon black shown in Table 1 was used as a comparative control, and the Mooney viscosity of this composition was taken as 100, and the index was shown in Table 3. It shows that it is excellent in workability, so that an index value is small.
(B) Scorch time In accordance with JIS K6300-1: 2001, a Mooney viscosity-time curve was measured using a Mooney viscometer, and a time (t5) increased by 5 points from the minimum value (Vm) of Mooney viscosity was obtained. This was the scorch time (minutes). The rubber composition containing the GPF grade carbon black shown in Table 1 was used as a comparative control, and the scorch time of this composition was taken as 100, and the index was shown in Table 3. The closer the index value is to 100, the better the vulcanization time and the better the workability.

(4) Rubber properties after vulcanization (a) Tensile stress
The vulcanized rubber obtained by vulcanization at 140 ° C for 30 minutes was measured for tensile stress at 200% elongation at 100 ° C and 300% elongation at normal temperature (23 ° C) according to JIS K6251: 2004. . The rubber composition containing the GPF grade carbon black shown in Table 1 was used as a comparative control, and the tensile stress of this composition was taken as 100, and the index was shown in Table 3. The larger the index value, the greater the tensile stress and the higher the elastic modulus.
(B) Tensile strength
The vulcanized rubber obtained by vulcanization at 140 ° C. for 30 minutes was measured for the tensile strength (Tb) at room temperature (23 ° C.) and 100 ° C. according to JIS K6251: 2004. The rubber composition containing the GPF grade carbon black shown in Table 1 was used as a comparative control, and the tensile strength of this composition was taken as 100, and the index was shown in Table 3. The larger the index value, the higher the resistance to fracture and the better the reinforcement.

  From the results of Examples 1 to 3 shown in Table 3, by adjusting the mixing ratio, the reinforcing effect is obtained even if it is added to the rubber component, even though the carbide obtained from the polymer waste is included. It turns out that the carbon material for rubber reinforcement which can fully exhibit is obtained. Moreover, from Examples 4-5, it turns out that tensile stress falls by not performing the mixing | blending by the excessive mixing | blending of a carbide | carbonized_material (A) or a predetermined procedure.

DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Pyrolysis furnace 3 Anoxic gas supply source 4 Circulation path 5 Oil content recovery device 6 Polymer waste 7 Decomposition device 8 External heating means 9 Flowmeter 10 Damper 11 Blower 12 Dry distillation tower 13 Recovery tank 14 Hot air furnace 15 Ventilator 16 Exhaust gas treatment device

Claims (2)

Look-containing carbide obtained by pyrolysis or incomplete combustion of polymer waste (A), the step of mixing the carbon black (B),
The method for producing a rubber material for reinforcing rubber, wherein the carbide (A) and the carbon black (B) are granulated independently and then mixed .   The carbon for rubber reinforcement according to claim 1, wherein a mixing mass ratio (A / B) of the carbide (A) and the carbon black (B) is within a range of 10/90 to 50/50. Material manufacturing method.

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