JP5693057B2 - CARBIDE, PROCESS FOR PRODUCING THE SAME, RUBBER COMPOSITION AND TIRE - Google Patents

Description

  The present invention relates to a carbide, a method for producing the carbide, a rubber composition obtained by blending the carbide, and a tire using the rubber composition, and more particularly, a carbide having high toluene coloring permeability from a polymer waste. It is related with the manufacturing method of the carbide | carbonized_material which can collect | recover.

  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, Utility Model Registration No. 3095293 (Patent Document 1) discloses a dry distillation method widely used as a thermal decomposition method. However, although the dry distillation method described in Patent Document 1 heats the dry distillation furnace by shutting off air, it is necessary to let the gas generated by the pyrolysis reaction escape to the outside of the system, so that the dry distillation furnace is completely sealed. Difficult to do. Moreover, the dry distillation system described in Patent Document 1 has a structure in which gas is released out of the system by a combustion furnace. When the decomposition of polymer plastics approaches the end, the generation of gas decreases and the pressure inside the dry distillation furnace may become lower than outside the system, so a large amount of air flows back into the dry distillation furnace Risk of explosion. Further, in the dry distillation method described in Patent Document 1, even when the decomposition of the polymer plastics is completed, cracked oil tends to remain in the generated carbide, so when the inside of the dry distillation furnace is at a high temperature, There is a risk of explosion due to ignition of cracked oil due to the backflow of air. Therefore, it is ideal to constantly introduce an inert gas into the system and keep the pressure in the system higher than the external pressure. However, always introducing the inert gas into the system reduces the cost of thermal decomposition. It becomes a factor to raise.

  Further, in recent years, as a thermal decomposition method for polymer waste such as used tires, oil is removed from the pyrolysis gas generated by the thermal decomposition of the polymer waste, and the heat from which the oil has been removed is removed. A method of using the cracked gas as a heat source for the pyrolysis reaction by reheating and recirculating the cracked gas is also frequently used (see, for example, JP-T-2002-523552 (Patent Document 2)). In this method, the gas always flows between the contents stored in the reactor, so the contents are rapidly decomposed, and no cracked oil remains in the carbide obtained at the end of the decomposition, and further, There is little risk of explosion. However, in such a method, since a heater for reheating the pyrolysis gas is installed at a position away from the reactor (pyrolysis kettle), heat easily escapes and heat utilization efficiency is poor. In addition, a pressure difference is generated before and after the blower (or pump) for circulating the pyrolysis gas, which makes it easier for air to enter the system than the seal portion of the hook used for pyrolysis. Furthermore, the carbide obtained by pyrolysis is oxidized by the inflow of the air, the acidity of the finally obtained carbide is increased, and it tends to be unsuitable as a rubber compounding carbide imparting reinforcing performance.

  Furthermore, the circulation system of the pyrolysis gas described in Patent Document 2 is to install a blower (or pump) in the system and circulate the pyrolysis gas by a pressure difference generated before and after the blower. For example, in the schematic diagram disclosed in Patent Document 2, the blower is located downstream of the condenser for recovering oil and upstream of the heat exchanger and heater for reheating (that is, the gas temperature is at room temperature). It is installed nearby. Here, in order to improve heat utilization efficiency, the heat exchanger and the heater are usually provided with many curved portions in the piping. For this reason, the pressure loss in this portion is large and the pressure in the hook is the lowest, so the negative pressure is usually about 1 kPa or more. Even with such a pressure difference, if the shuttle seal is not perfect, a small amount of air flows from outside the system. If the inflow of the air occurs for a long time, the carbide in the kettle becomes susceptible to oxidation. In particular, the higher the carbon content of the carbide produced by pyrolysis, the easier it is to oxidize, and the inflow of air increases the acidity, making it unsuitable as a rubber compounding carbide.

  In addition, in the pyrolysis kettle, the work for throwing in the tire and the work for taking out the pyrolyzed carbide, steel cord, steel wire, etc. are performed. Removal and installation work is also required. For this reason, the seal | sticker of a hook lid is easy to be damaged and it becomes easy to become a poor seal. Further, the temperature in the pyrolysis kettle is often as high as 400 ° C. or higher, and the seal portion is likely to be deformed or altered. As described above, it is very difficult to always keep the seal portion located between the pyrolysis kettle and its lid completely.

On the other hand, in JP-A-7-310076 (Patent Document 3), vulcanized rubber is thermally decomposed in the presence of a hydrogen-donating solvent as a method for recovering carbon black in a state close to the original higher-order aggregate structure. A method for producing liquid hydrocarbons and carbon blacks has been proposed. Specifically, 23 g of 30 mesh powder rubber and 57.5 g of tetralin obtained from a used tire were added to an electromagnetic stirring autoclave. Then, after reacting at an initial pressure of nitrogen gas of 20 kg / cm ² and a reaction temperature of 440 ° C. for 1 hour, the autoclave is cooled to obtain a gas product and a slurry product, and then the slurry product is filtered, By obtaining carbon black and a liquid substance and further distilling the liquid substance, a liquid hydrocarbon (cracked oil) containing a plurality of components is obtained. However, in a process of recovering carbide generated by pyrolysis by pyrolyzing the polymer waste in a pyrolysis furnace containing polymer waste having completely different pyrolysis conditions from Patent Document 3. What effect is exhibited when the thermal decomposition reaction is carried out while adding the polymer waste to the thermal decomposition furnace without immersing it in the liquid hydrocarbon of the hydrogen donating solvent? It is not described at all whether a reaction product is obtained.

Utility Model Registration No. 3095293 Special table 2002-523552 gazette JP 7-310076 A

  An object of the present invention is to solve the technical problem of effectively preventing deterioration due to oxidation of carbides obtained by a thermal decomposition reaction, and to recover carbides having high toluene coloring permeability from polymer wastes. The object is to provide a method for producing possible carbides. In addition, the numerical value of toluene coloring permeability is an index for evaluating the amount of hydrocarbon components not completely decomposed contained in the carbide obtained by the thermal decomposition reaction, and when this numerical value is low, This means that the content of undecomposed hydrocarbon components is large. If the content of the hydrocarbon component is high, there is a possibility of contamination due to the rubber surface when blended into the rubber component, and in addition, the health and environment due to the aromatic hydrocarbon contained in the hydrocarbon component Since the influence on the surface is concerned, this value is preferably high. Another object of the present invention is to provide a carbide obtained by the above production method, a rubber composition obtained by blending the carbide, and a tire using the rubber composition.

  As a result of intensive studies to achieve the above object, the present inventors have determined that in the thermal decomposition reaction of the polymer waste, the polymer waste has a liquid hydrocarbon having a boiling point in the range of 150 ° C to 400 ° C. By adding dropwise, it was found that a carbide having a high transparency to toluene coloring and a low oxidation degree was obtained, and the present invention was completed.

That is, the manufacturing method of the carbide of the present invention is:
In a pyrolysis furnace containing tire waste , liquid hydrocarbon having a boiling point in the range of 150 ° C. to 400 ° C. is dropped into the tire waste and added at an addition rate of 180 to 1800 ml / hr . The method includes pyrolyzing the tire waste to generate pyrolysis gas .

  “Carbide” in the present application refers to a solid that is produced and left after a substance containing an organic substance is used as a raw material, and the raw material is released from a gas body and a liquid component by a thermal decomposition reaction by heating. It may contain an inorganic substance.

In a preferred embodiment of the method for producing carbide according to the present invention, the liquid hydrocarbon is continuously supplied by dropping until the thermal decomposition reaction of the tire waste is completed.

  In the method for producing carbide according to the present invention, it is preferable to control the temperature at the time of pyrolysis within a range of 300 to 600 ° C. in the step of generating the pyrolysis gas.

  Further, the carbide of the present invention is characterized by being obtained by the above production method, its toluene color permeability is preferably 90% or more, and its total acidity is preferably 0.07 meq / g or less. The average particle size is preferably 50 μm or less. Furthermore, the rubber composition of the present invention is characterized by blending the carbide, and the tire of the present invention is characterized by using the rubber composition.

  According to the present invention, in the thermal decomposition of polymer waste, the polymer waste is dropped into the polymer waste by adding liquid hydrocarbon having a boiling point in the range of 150 ° C. to 400 ° C. From this, it is possible to recover a carbide having a high toluene coloring permeability. This is because the liquid hydrocarbon added to the polymer waste promotes the thermal decomposition reaction of the polymer waste, and also dissolves undecomposed components in the polymer waste, thereby reducing the toluene coloring permeability. We think that high carbides can be obtained. In addition to this, when liquid hydrocarbons are introduced into a heated pyrolysis furnace, the liquid hydrocarbons evaporate and expand in the space of the pyrolysis furnace, thereby causing equipment in the carbide production system. It is possible to prevent the negative pressure in the system space generated by the operation of the system, and to prevent the inflow of air from outside the system to the pyrolysis furnace, and to lower the oxidation degree of the generated carbide Can do. Therefore, the carbide recovered by the production method of the present invention has a high toluene coloring permeability and can also maintain a low total acidity. It is possible to maintain the characteristics sufficiently. Furthermore, it is possible to provide a rubber composition obtained by blending the above carbide and a tire using the rubber composition. In addition, the rubber composition formed by blending the above carbide is not inferior to a rubber composition blended with ordinary carbon black.

It is the schematic of an example which shows the manufacturing apparatus of the carbide | carbonized_material suitable for implementation of this invention. It is a figure which shows the relationship between the rubber characteristic of a rubber composition, and total acidity. It is the schematic of an example of the manufacturing apparatus of the carbide | carbonized_material used for the comparative example.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an example of a carbide production apparatus suitable for carrying out the present invention. First, the method for producing carbide according to the present invention, that is, the method for producing carbide obtained by pyrolysis of polymer waste, includes the polymer waste in the pyrolysis furnace 2 in which the polymer waste 1 is accommodated. A step of pyrolyzing the product 1 to generate pyrolysis gas. As a result, the thermal decomposition reaction of the polymer waste 1 proceeds, and carbides are generated in the pyrolysis furnace 2 after the thermal decomposition of the polymer waste 1. Here, in the carbide production method of the present invention, it is preferable to perform the pyrolysis reaction of the polymer waste 1 using the external heating means 3 for heating the pyrolysis furnace 2 from the outside. Since the carbide manufacturing apparatus includes the external heating means 3, the polymer waste 1 in the pyrolysis furnace 2 can be indirectly heated from the outside of the pyrolysis furnace 2, so that it is introduced into the pyrolysis furnace 2 as a heat source. The use of gas can be avoided. This suppresses the generation of solid dust (fine suspended matter derived from polymer waste) that is swollen from the pyrolysis furnace 2 and mixed in the gas and circulates in the apparatus together with the gas. Can also be suppressed.

  The polymer waste 1 mainly refers to organic waste, specifically, rubber material waste such as tire waste (eg, spew, buff powder, 4-32 divided tires), Polymer materials obtained by (co) polymerization reaction of hydrocarbon monomers, such as polyethylene, polypropylene, styrene-butadiene copolymers, etc. Copolymers of hydrocarbon monomers with other monomers, such as ethylene-vinyl acetate copolymer Examples thereof include (co) polymers of halogenated derivatives of coalesced hydrocarbon monomers, for example, resin material waste such as polyvinyl chloride. In addition, steel cords, wires, and the like may be mixed with carbides in the residue after pyrolyzing the tire waste.

  The pyrolysis furnace 2 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. Further, the external heating means 3 is not particularly limited, and a normal heater can be used. More specifically, a silicon carbide heating element or other heating element disposed around the pyrolysis furnace is used. It may be used, or a space in which a heat medium is introduced into a space formed between the pyrolysis furnace by a container disposed around the pyrolysis furnace may be used.

  In the carbide production method of the present invention, an inert gas may be introduced into the pyrolysis furnace 2 via the inert gas supply line 4. For example, when purging the inside of the pyrolysis furnace 2 at the start of pyrolysis or stopping the supply of the liquid hydrocarbon at the end of pyrolysis, by introducing an inert gas into the pyrolysis furnace 2, Thermal decomposition in an oxygen-free state becomes more reliable, and oxidation of the generated carbide can be suppressed. Further, since an inert gas is not used as a carrier, it is not always necessary to introduce the gas into the pyrolysis furnace 2, and the amount used is very small, and the cost for recovering the carbide is hardly affected. In addition, as an inert gas, nitrogen, argon, etc. can be mentioned, for example.

  Further, the method for producing carbide of the present invention includes a step of dropping and adding liquid hydrocarbon having a boiling point in the range of 150 ° C. to 400 ° C. to the polymer waste 1 to be thermally decomposed. Liquid hydrocarbon added dropwise to polymer waste promotes the thermal decomposition reaction of polymer waste, and dissolves undecomposed components in polymer waste, thereby allowing permeation of toluene. A high degree of carbide is obtained. Further, when the liquid hydrocarbon is introduced into the heated pyrolysis furnace, the liquid hydrocarbon evaporates and expands in the space of the pyrolysis furnace, thereby causing the operation of equipment in the carbide production apparatus system. It is possible to prevent the negative pressure in the generated internal space from being buffered and counteracted, and to prevent the inflow of air from outside the system to the pyrolysis furnace, and to keep the degree of oxidation of the generated carbide low. .

  Moreover, it is preferable that the manufacturing method of the carbide | carbonized_material of this invention includes the process of collect | recovering the liquid hydrocarbons whose boiling point is the range of 150 to 400 degreeC from the pyrolysis gas generated by the thermal decomposition of the polymer waste 1. . According to the method for producing a carbide of the present invention, it is preferable to supply the liquid hydrocarbon to the pyrolysis furnace 2 while circulating the liquid hydrocarbon as described later. In this case, it is necessary to recover the liquid hydrocarbon from the pyrolysis gas. is there. And in the manufacturing method of the carbide | carbonized_material of this invention, it becomes possible to collect | recover the said liquid hydrocarbons by collect | recovering the oil components which cooled and condensed the said pyrolysis gas. For this reason, it is preferable that the manufacturing apparatus of the carbide | carbonized_material used for implementation of this invention is equipped with a cooling tower (condenser). As shown in FIG. 1, if a plurality of cooling towers are used, the oil obtained from the pyrolysis gas can be divided according to its boiling point. For example, in a carbide production apparatus, a first cooling tower 5 (high-boiling oil recovery tower) on the upstream side of the gas flow path and a second cooling tower 6 (low-boiling oil recovery) on the downstream side of the gas flow path. Tower). In the manufacturing apparatus shown in FIG. 1, the pyrolysis gas is introduced from the pyrolysis furnace 2 to the cooling tower 5 via the pyrolysis gas supply line 7. Further, the cooling tower 5 collects an oil component (pyrolysis oil 8) having a relatively high boiling point, so that a high-temperature cooling medium introduction line 9 for introducing a high-temperature cooling medium and a high-temperature cooling medium lead-out line for discharging the high-temperature cooling medium. On the other hand, the cooling tower 6 is a low-temperature cooling medium in which a low-temperature cooling medium is introduced in order to recover the low-boiling oil 11 containing liquid hydrocarbons having a boiling point in the range of 150 ° C. to 400 ° C. It consists of a cooling tower equipped with an introduction line 12 and a low-temperature coolant delivery line 13 for discharging a low-temperature coolant. Here, examples of the cooling medium include water and silicon oil. The low-boiling oil 11 may contain components other than liquid hydrocarbons having a boiling point in the range of 150 ° C. to 400 ° C., since the components are components derived from polymer waste, Even if this is supplied to the thermal cracking furnace 2 together with the liquid hydrocarbon, the action of the present invention is not adversely affected. Moreover, each cooling tower is connected to a collection tank (not shown) through piping at the lower part, for example, and can also collect the collected oil. In addition, the gas which does not become oil may be incinerated by an exhaust gas combustion means such as a flare stack to be purified, or may be used as a heat source.

  Furthermore, it is preferable that the manufacturing method of the carbide | carbonized_material of this invention includes the process of supplying the liquid hydrocarbon whose boiling point is the range of 150 to 400 degreeC to the thermal cracking furnace 2, and circulating. When the liquid hydrocarbon is supplied into the pyrolysis furnace 2, it is evaporated and gasified in the heated pyrolysis furnace 2. The gasified hydrocarbon acts as a carrier for gas generated by thermal decomposition of the polymer waste 1 in the thermal decomposition furnace 2. Surprisingly, when the above liquid hydrocarbon is used as a carrier, the toluene coloring permeability of the carbide recovered from the polymer waste can be increased. The reason for this is that the liquid hydrocarbon acts as an eluent for the undecomposed component in the polymer waste that can be a reinforcing factor of the reinforcement, so that the undecomposed component in the polymer waste becomes a polymer. It is thought that it is eluted from the system waste 1. If the boiling point of the liquid hydrocarbon is less than 150 ° C., the liquid hydrocarbon is likely to evaporate at the moment when it is supplied into the pyrolysis furnace 2, and the contact time with the carbide generated by the pyrolysis is too short, so However, when the temperature exceeds 400 ° C., liquid hydrocarbons are difficult to evaporate and cover the surface of the carbide as it is and remain untouched. Since it may remain as a cracked hydrocarbon, there is a possibility that the effect of increasing the toluene coloring permeability cannot be sufficiently obtained.

  In the method for producing carbide according to the present invention, as the liquid hydrocarbon having a boiling point in the range of 150 ° C. to 400 ° C., specifically, isoprene derivatives, butadiene derivatives, styrene derivatives, tetralin, kerosene, creosote oil, aroma oil, etc. Can be mentioned.

  In the method for producing carbide according to the present invention, it is preferable to continuously supply the liquid hydrocarbon into the pyrolysis furnace 2 until the thermal decomposition reaction of the polymer waste 1 is completed. By continuously supplying the liquid hydrocarbon into the thermal cracking furnace 2, undecomposed components in the polymer waste can be efficiently removed, and the toluene coloring permeability is greatly increased. be able to. Moreover, by introducing and adding liquid hydrocarbons dropwise into the pyrolysis furnace 2, the liquid hydrocarbons are vaporized in the pyrolysis furnace 2, and the pressure in the pyrolysis furnace increases due to this phase transition. By continuously supplying the liquid hydrocarbons into the pyrolysis furnace, the internal pressure in the pyrolysis furnace is kept high, so that the inflow of air into the pyrolysis furnace in the prior art and the thermal decomposition by this Defects of product oxidation can be avoided. The liquid hydrocarbon addition rate is preferably a rate at which the internal pressure increase in the pyrolysis furnace can be maintained by continuous hydrocarbon addition and vaporization. An addition rate of several to several tens of drops per second, that is, a range of 180 to 1800 ml / hr is preferable. Here, in order to control the flow rate of the liquid hydrocarbon from the liquid hydrocarbon storage tank 15, it is preferable to introduce the liquid hydrocarbon into the thermal cracking furnace 2 through the liquid hydrocarbon supply pump 16 or the like.

  As described above, in a preferred embodiment of the method for producing carbide of the present invention, liquid hydrocarbon having a boiling point in the range of 150 ° C. to 400 ° C. is circulated. Thereby, this liquid hydrocarbon can be utilized efficiently. For example, as shown in FIG. 1, by introducing a low boiling point oil 11 containing the liquid hydrocarbon recovered in the cooling tower 6 into the thermal cracking furnace 2 through the liquid hydrocarbon supply line 14, the liquid carbonization is performed. A structure in which hydrogen repeatedly returns to the pyrolysis furnace 2 is formed, and the liquid hydrocarbon can be circulated to the pyrolysis furnace 2. Since it is difficult to recover the liquid hydrocarbon until the thermal decomposition reaction of the polymer waste 1 is started, the carbide production apparatus used in the practice of the present invention stores the liquid hydrocarbon. The liquid hydrocarbon storage tank 15 is preferably provided, and the liquid hydrocarbon is preferably supplied from the tank 15 into the pyrolysis furnace 2 via the liquid hydrocarbon supply line 14.

  In the method for producing carbide according to the present invention, it is preferable to control the temperature at the time of pyrolysis within a range of 300 to 600 ° C. in the step of generating pyrolysis gas from the polymer waste 1. If the temperature at the time of thermal decomposition is within the above specified range, the polymer waste can be stably and continuously decomposed. If the temperature during the pyrolysis is less than 300 ° C., the pyrolysis reaction does not proceed sufficiently, which may result in the formation of carbides in which the components to be decomposed are not completely removed. Undesirable reforming reactions and activation reactions occur between the generated carbides and the components that can be contained in the gas, increasing the total acidity in the carbides, or being porous and adversely affecting the reinforcing effect on the rubber. There is a risk of forming carbides that can be affected. Here, in order to control the temperature at the time of thermal decomposition, the external heating means 3 etc. may be utilized.

  In the carbide manufacturing method of the present invention, the carbide remaining in the pyrolysis furnace after the thermal decomposition of the polymer waste 1 is recovered. The carbide obtained by the above-described manufacturing method is mixed with steel cords, wires, etc., which are aggregates of tires when, for example, tire waste is pyrolyzed. It is preferable to separate it from a steel cord or a wire using In addition, since the carbide obtained by the above-described manufacturing method is composed of a lump part and a powdery part aggregated during the carbonization process, for example, the carbide recovered by a pulverization process using a pulverizer or the like is finely crushed. Further, it is preferable to extract a carbide having a specific particle size by a classification process using a classifier or the like.

  In the carbide manufacturing method of the present invention, although not shown in the drawings, in order to control the gas flow rate, a flow meter for measuring the gas flow rate, a valve for adjusting the gas flow rate according to the opening degree, and keeping the gas flow rate constant A blower or the like can be used. In the carbide production method of the present invention, the oxygen concentration in the production apparatus is preferably controlled to 1% by volume or less. If the oxygen concentration in the production apparatus is 1% by volume or less, oxidation of carbides remaining in the pyrolysis furnace after pyrolysis can be more reliably suppressed, quality does not deteriorate, and even if blended with a rubber component, rubber Carbide that can sufficiently maintain the characteristics can be obtained more reliably. The oxygen concentration in the production apparatus can be measured by, for example, a zirconia oxygen sensor using a solid electrolyte zirconia-based oxygen concentration cell.

  Next, the carbide of the present invention will be described in detail. The carbide of the present invention is a carbide obtained by the above-described production method, and is characterized in that its toluene color permeability is high, and the toluene color permeability is preferably 90% or more. When the toluene coloring permeability is 90% or more, the performance deterioration in the reinforcing effect of the recovered carbide is suppressed, and it can be reused as a rubber reinforcing filler. In addition, the toluene coloring transmittance of the carbide is measured in accordance with JIS K6218-4: 2005 “Carbon black for rubber—incidental characteristics—Part 4: Determination of toluene coloring transmittance”.

  Further, the carbide of the present invention is suitable as a compound for rubber because its surface oxidation is suppressed by the effect of increasing the pressure inside the pyrolysis furnace by the above production method. In addition, as an index for evaluating the degree of oxidation of carbide, there is “total acidity”, and if this value is large, it means that the surface of the carbide is oxidized, and the carbide is not suitable as a compounding agent for rubber. It is known. Since the carbide of the present invention is obtained by the above-described production method, the total acidity can be 0.07 meq / g or less. If the total acidity is 0.07 meq / g or less, when the recovered carbide is mixed with pure carbon black (100% carbon black), the physical properties of the rubber composition are hardly deteriorated, and the recovered carbide is reused. It becomes possible to do. In addition, FIG. 2 is a figure which shows the relationship between the rubber characteristic of a rubber composition, and total acidity. The vertical axis in FIG. 2 represents 20% by mass of the carbide of the present invention and 80% by mass of GPF class carbon black when the tensile stress at 300% elongation of the rubber composition containing only GPF class carbon black is expressed as 100. The index value of the tensile stress at the time of 300% expansion | extension of the rubber composition accompanying the change of the total acidity of the carbide | carbonized_material when mix | blending with this is shown.

  The method for measuring the total acidity is as follows. First, 1 g of carbide is precisely weighed, transferred to a flat bottom flask, added with 50 ml of 0.002N NaOH aqueous solution, and dispersed with ultrasonic waves. Then, a condenser tube is attached to the flat bottom flask and boiled for 2 hours while refluxing. The dispersion is cooled and solubilized, and a portion thereof is titrated with a 0.002N NaOH aqueous solution, and the amount of NaOH used in the neutralization reaction per 1 g of carbide is determined from the remaining amount of NaOH left unreacted. . The unit is expressed in milliequivalents (meq / g) per unit mass.

  Furthermore, the carbide of the present invention is preferably as fine as the particle size of the carbon black from the viewpoint of being used in place of part of the carbon black compounded in the tire rubber composition, and the average particle size is 50 μm. Or less, more preferably 10 μm or less.

  Next, the rubber composition and tire of the present invention will be described in detail. The rubber composition of the present invention is characterized by comprising a carbide obtained by the above production method. In the rubber composition of the present invention, for example, in addition to the above carbide and rubber components, compounding agents usually used in the rubber industry, such as fillers, softeners, silane coupling agents, stearic acid, anti-aging agents, Zinc white, a vulcanization accelerator, a vulcanizing agent, and the like can be appropriately blended depending on the purpose. As these compounding agents, commercially available products can be suitably used. In addition, the said rubber composition can be manufactured by mix | blending various compounding agents suitably selected with the said carbide | carbonized_material with the said carbide | carbonized_material as needed, knead | mixing, heat-inserting, extrusion, etc.

  The rubber component that can be used in the rubber composition of the present invention is not particularly limited. In addition to natural rubber (NR), polyisoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), polybutadiene. Synthetic rubbers such as rubber (BR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), halogenated butyl rubber, acrylonitrile-butadiene rubber (NBR) can be used. You may use individually and may blend and use 2 or more types.

  In the rubber composition of the present invention, the carbide obtained by the above production method can be blended with carbon black. By combining the carbide with carbon black, it is possible to suppress deterioration in physical properties of the rubber composition. The carbide content in the total of the carbide and carbon black is preferably in the range of 1 to 20% by mass. If the content of the carbide is within the above specified range, the physical property deterioration of the rubber composition can be reliably suppressed.

  The tire of the present invention is characterized by using the rubber composition described above, and can reduce the deterioration of the physical properties of the tire even though the carbide recovered from the polymer waste is reused. The tire of the present invention is not particularly limited except that the above rubber composition 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.

Example 1
Carbide was recovered from waste truck tires using the manufacturing apparatus shown in FIG.
Specifically, after putting about 100kg of waste truck tires into 32 parts (polymer waste 1) in the pyrolysis furnace 2 (capacity: 0.5m ³ ) and replacing the production equipment with nitrogen gas The heater as the external heating means 3 is turned on, and white kerosene (boiling point range: 150 to 280 ° C .; manufactured by Nippon Oil Corporation; ENEOS kerosene) is heated from the liquid hydrocarbon storage tank 15 at a rate of 1 L / hr. The solution was dropped into the decomposition furnace 2. The temperature in the pyrolysis furnace 2 was raised to about 500 ° C. and this temperature was maintained. One hour after turning on the heater, the low boiling point oil 11 began to distill into the cooling tower 6. About 4 hours after the heater was turned on, the increase in the amount of distillate in the cooling towers 5 and 6 became constant. Therefore, it was determined that the pyrolysis reaction was completed, and the liquid hydrocarbon feed pump 16 was operated. Was stopped, the supply of white kerosene from the liquid hydrocarbon storage tank 15 was stopped, and nitrogen gas was introduced into the pyrolysis furnace 2 through the inert gas supply line 4 at a rate of 1 L / min. After cooling the temperature in the pyrolysis furnace 2 to about 100 ° C. or less, the pyrolysis furnace 2 was opened and the carbides were recovered. The recovered carbide contained iron products such as steel cords as tire materials, and was removed with a magnetic separator. Further, the carbide was pulverized on a stainless steel wire mesh, and the carbide that passed through the wire mesh was further pulverized by a jet airflow pulverizer. The average particle size of the pulverized carbide was 4.13 μm.

(Example 2)
Using waste passenger car tires as polymer waste 1, changing the reaction conditions in the pyrolysis furnace 2 to 550 ° C, and changing liquid hydrocarbons from white kerosene to tetralin (boiling point: 207 ° C; Kanto Chemical) The carbide was recovered in the same manner as in Example 1 except that the addition rate of tetralin was dropped to 500 ml / hr. The average particle size of the pulverized carbide was 3.76 μm.

(Comparative Example 1)
From the waste truck tire using the production apparatus shown in FIG. 3 (the apparatus that reheats and circulates the pyrolysis gas generated by pyrolysis of polymer waste and does not have liquid hydrocarbon introduction means) The carbide was recovered.
Specifically, about 100 kg of 32 truck cut products of waste truck tires are put into a pyrolysis kettle (capacity: 0.5 m ³ ), and the inside of the production equipment is filled with nitrogen gas via a nitrogen gas supply line (not shown). After the replacement, the gas temperature was raised to about 500 ° C. by a heat exchanger while circulating the nitrogen gas, and this temperature was maintained. Distillation started in the condenser 1 hour after the start of heating by the heat exchanger. Distillation stopped 4 hours after the start of heating by the heat exchanger. Stoppage of the distillation showed that the thermal decomposition reaction was completed, and the heat exchanger was stopped and the system was left to cool for about 12 hours. After cooling, the pyrolysis kettle was opened and the carbides were recovered. The recovered carbide contained iron products such as steel cords as tire materials, and was removed with a magnetic separator. Further, the carbide was pulverized on a stainless steel wire mesh, and the carbide that passed through the wire mesh was further pulverized by a jet airflow pulverizer. In addition, the pulverized product was classified with an air classifier having rotating blades to remove foreign particles such as coarse powder having a particle size of 50 μm or more and sand, and fine carbides were recovered. The average particle size of the fine carbide was 3.94 μm.

(Comparative Example 2)
Carbide was recovered from waste truck tires using the manufacturing apparatus shown in FIG. However, in Comparative Example 2, white gas oil was not introduced from the liquid hydrocarbon storage tank 15, and nitrogen gas was continuously introduced into the pyrolysis furnace 2 via the inert gas supply line 4.
Specifically, after putting about 100kg of waste truck tires into 32 parts (polymer waste 1) in the pyrolysis furnace 2 (capacity: 0.5m ³ ) and replacing the production equipment with nitrogen gas The heater as the external heating means 3 was turned on. White kerosene was not dropped from the liquid hydrocarbon storage tank 15, and a normal dry distillation type pyrolysis method was performed at a thermal decomposition temperature of about 500 ° C. The pyrolysis oil 8 was distilled into the cooling tower 5 in which a high-temperature cooling medium was circulated. Distillation into the cooling tower 5 stopped approximately 5 hours after the heater was turned on. Thereafter, the pyrolysis furnace 2 was cooled to room temperature, and the carbides were recovered. The recovered carbide was treated in the same manner as in Comparative Example 1 to recover fine carbide. The average particle size of the fine carbide was 4.28 μm.

  About the carbide | carbonized_material of Examples 1-2 and Comparative Examples 1-2 which were manufactured as mentioned above, the total acidity and toluene coloring transmittance | permeability were measured by the above-mentioned method. The results are shown in Table 1.

  Using the carbides of Examples 1 and 2 and Comparative Examples 1 and 2, a rubber composition was prepared by a compounding recipe using three kinds of rubbers shown in Table 2, and the rubber composition was unvulcanized and vulcanized. The later rubber properties were measured by the following method. The results are shown in Tables 3-5.

(1) 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 The rubber composition containing only GPF grade carbon black [manufactured by Asahi Carbon Co., Ltd., trade name: Asahi # 55] was indexed with the Mooney viscosity as 100. 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). Here, the scorch time of a rubber composition in which only GPF grade carbon black [manufactured by Asahi Carbon Co., Ltd., trade name: Asahi # 55] was blended was indicated as 100. The closer the index value is to 100, the better the vulcanization time and the better the workability.

(2) Rubber properties after vulcanization (a) Hardness
The vulcanized rubber obtained by vulcanization at 140 ° C. for 30 minutes was evaluated using a durometer hardness tester (type A) in accordance with JIS K6253: 2006. Specifically, a push needle was pushed into the surface of the rubber test piece of vulcanized rubber for 3 seconds, and the hardness of the rubber test piece was obtained from the push depth of the push needle. Here, the hardness of a rubber composition in which only GPF grade carbon black [manufactured by Asahi Carbon Co., Ltd., trade name: Asahi # 55] was blended was expressed as an index. The larger the index value, the higher the hardness of the rubber composition.
(B) Tensile stress
A vulcanized rubber obtained by vulcanization at 140 ° C. for 30 minutes was measured in accordance with JIS K6251: 2004, and the tensile stress at 100% elongation and 300% elongation at room temperature was measured. The rubber composition in which only a product of Carbon Co., Ltd., trade name: Asahi # 55] was blended was expressed as an index with the tensile stress as 100. The larger the index value, the greater the tensile stress and the higher the elastic modulus.
(C) Tensile strength
A vulcanized rubber obtained by vulcanization at 140 ° C. for 30 minutes was measured for tensile strength (Tb) at room temperature in accordance with JIS K6251: 2004, and GPF grade carbon black [manufactured by Asahi Carbon Co., Ltd. , Trade name: Asahi # 55], the rubber composition containing only Asahi # 55] was indicated as an index with the tensile strength as 100. The larger the index value, the higher the resistance to fracture and the better the reinforcement.
(D) Elongation at cutting
A vulcanized rubber obtained by vulcanization at 140 ° C. for 30 minutes was measured for elongation at room temperature in accordance with JIS K6251: 2004. GPF grade carbon black [trade name, manufactured by Asahi Carbon Co., Ltd. : Asahi # 55], the rubber composition containing only Asahi # 55] was expressed as an index with the elongation at break as 100. It shows that the reinforcement effect to the rubber composition of the filler component mix | blended is so high that an index value is large.

* 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 Mixture of 20% by mass of any one of Examples 1-2 and Comparative Examples 1-2 and 80% by mass of GPF grade carbon black.
* 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.

  From Tables 3 to 5, the carbides obtained by the production method of the present invention described in Examples 1 and 2 are obtained by dropping a liquid hydrocarbon having a boiling point in the range of 150 ° C to 400 ° C into the polymer waste. In order to add, the obtained carbide | carbonized_material has high toluene coloring transmittance | permeability compared with the carbide | carbonized_material obtained by the manufacturing method as described in Comparative Examples 1-2, and the total acidity is suppressed to 0.07 meq / g or less. Therefore, the rubber compositions of Examples 1 and 2 both exceed 5% for various rubber properties of unvulcanized rubber and vulcanized rubber as compared with the rubber composition containing only GPF grade carbon black. It can be seen that there is no reduction.

DESCRIPTION OF SYMBOLS 1 Polymer waste 2 Pyrolysis furnace 3 External heating means 4 Inert gas supply line 5 Cooling tower 6 Cooling tower 7 Pyrolysis gas supply line 8 Pyrolysis oil 9 High-temperature coolant introduction line 10 High-temperature coolant delivery line 11 Low Boiling point oil 12 Low-temperature coolant introduction line 13 Low-temperature coolant delivery line 14 Liquid hydrocarbon supply line 15 Liquid hydrocarbon storage tank 16 Liquid hydrocarbon supply pump

Claims (9)

In a pyrolysis furnace containing tire waste , liquid hydrocarbon having a boiling point in the range of 150 ° C. to 400 ° C. is dropped into the tire waste and added at an addition rate of 180 to 1800 ml / hr . A method for producing carbide comprising the step of pyrolyzing the tire waste to generate pyrolysis gas .   The method for producing carbide according to claim 1, wherein the liquid hydrocarbon is continuously supplied until the thermal decomposition reaction of the tire waste is completed.   The method for producing a carbide according to claim 1, wherein, in the step of generating the pyrolysis gas, a temperature at the time of pyrolysis is controlled in a range of 300 to 600 ° C.   The carbide obtained by the manufacturing method in any one of Claims 1-3.   The carbide according to claim 4, wherein the toluene coloring transmittance is 90% or more.   The carbide according to claim 4, wherein the total acidity is 0.07 meq / g or less.   The carbide according to claim 4, having an average particle size of 50 μm or less.   A rubber composition comprising the carbide according to any one of claims 4 to 7.   A tire using the rubber composition according to claim 8.

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