Modified recycled carbon black and rubber composition

Abstract

A modified recycled carbon black, characterized in that the N2SA is 50m 2 / g and above and 250m 2 / g or less, in the Raman spectrum measured by laser Raman spectroscopy at an excitation wavelength of 532nm, the ‑1 When the peak intensity of the peak with a peak top in the range of 1580±20cm ‑1 The peak intensity of the peak having a peak top in the range of 84 to 111 is greater than or equal to 84 and less than or equal to 111. According to the present invention, it is possible to provide recycled carbon black which has a strong bond with a rubber component and has high reinforcing properties for rubber products.

Description

Technical Field

[0001] The present invention relates to recycled carbon black having a modified surface state, a method for producing the same, and a rubber composition using the same. Background Art

[0002] In recent years, measures such as carbon neutrality and sustainability have become popular in order to reduce the impact on the global environment. In addition, the carbon black industry has also studied the use of recycled carbon black obtained by thermal cracking rubber products such as waste tires as part of sustainable activities.

[0003] As a method for producing recycled carbon black by thermal cracking of waste tires, for example, Patent Document 1 discloses that waste tires are thermally cracked at about 500° C. while circulating nitrogen gas.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 5813985

[0007] Patent Document 2: WO2013 / 095145A1 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] However, recycled carbon black obtained by thermally cracking rubber products such as waste tires has rubber residues mainly composed of rubber carbonized products attached to its surface. When the rubber residues are mixed in a rubber composition, the adsorption of the recycled carbon black to the rubber component is hindered.

[0010] Therefore, in the recycled carbon black, since the bonding with the rubber component is weak, there is a problem that the reinforcement property of the rubber product is low.

[0011] Therefore, an object of the present invention is to provide recycled carbon black which has a strong bond with a rubber component and has high reinforcing properties for rubber products.

[0012] Solutions for solving problems

[0013] The present inventors have conducted intensive research and found that:

[0014] The recycled carbon black is brought into contact with an oxidizing gas under heating, thereby oxidizing and removing the rubber residue composed mainly of rubber carbide attached to the surface of the recycled carbon black. This allows the surface of the recycled carbon black to be exposed, thereby enhancing the bonding with the rubber component and, therefore, improving the reinforcement of the rubber product.

[0015] In addition, the present inventors found the following. That is, they found that:

[0016] When the rubber residue attached to the surface of the recycled carbon black is oxidized and decomposed and removed, if the oxidation of the recycled carbon black itself is excessive, although the bonding with the rubber component becomes higher, the specific surface area becomes too high, and the aggregation force of the recycled carbon black becomes too large, so the dispersion in the rubber becomes poor and the rubber reinforcement property does not increase. However, the recycled carbon black with a larger specific surface area is brought into contact with an oxidizing gas, and then brought into contact with a hydrocarbon under heating to generate carbides, which fill the pores generated on the surface of the recycled carbon black, thereby adjusting the specific surface area, reducing the aggregation force, and improving the reinforcement property of the rubber product, thereby completing the present invention.

[0017] That is, the present invention provides the following solutions:

[0018] (1) A modified recycled carbon black, characterized in that:

[0019] N 2 SA is 50m 2 / g and above and 250m 2 / g or less,

[0020] In the Raman spectrum measured by laser Raman spectroscopy at an excitation wavelength of 532 nm, the -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is greater than or equal to 84 and less than or equal to 111.

[0021] (2) The modified recycled carbon black according to (1), characterized in that the ash content is 3.0% or more and 50.0% or less.

[0022] (3) A modified recycled carbon black, characterized in that it is obtained by contacting recycled carbon black having rubber carbonized matter attached thereto with an oxidizing gas in a reaction furnace heated to 600° C. or higher and 1400° C. or lower.

[0023] The modified recycled carbon black 2 SA is 50m 2 / g and above and 250m 2 / g or less,

[0024] In the Raman spectrum measured by laser Raman spectroscopy at an excitation wavelength of 532 nm, the -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is greater than or equal to 84 and less than or equal to 111.

[0025] (4) A modified recycled carbon black, characterized in that it is obtained by carrying out a step of bringing recycled carbon black having rubber carbonized matter attached thereto into contact with an oxidizing gas and a step of bringing recycled carbon black into contact with a hydrocarbon gas in a reaction furnace heated to 600° C. or higher and 1400° C. or lower,

[0026] The modified recycled carbon black 2 SA is 50m 2 / g and above and 250m 2 / g or less,

[0027] In the Raman spectrum measured by laser Raman spectroscopy at an excitation wavelength of 532 nm, the -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is greater than or equal to 84 and less than or equal to 111.

[0028] (5) The modified recycled carbon black according to (3) or (4), characterized in that the recycled carbon black to which the rubber carbide is attached is a carbon black having a Raman spectrum measured at an excitation wavelength of 532 nm using laser Raman spectroscopy at 1350±20cm -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is greater than or equal to 112 and less than or equal to 200.

[0029] (6) A method for producing modified recycled carbon black, characterized by comprising a step of bringing recycled carbon black having rubber carbonized matter attached thereto into contact with an oxidizing gas in a reaction furnace heated to a temperature of 600° C. to 1400° C.

[0030] (7) A method for producing modified recycled carbon black, characterized by comprising a step of bringing recycled carbon black having rubber carbonized matter attached thereto into contact with an oxidizing gas and a step of bringing recycled carbon black into contact with a hydrocarbon gas in a reaction furnace heated to a temperature of not less than 600° C. and not more than 1400° C.

[0031] (8) The method for producing modified and recycled carbon black according to (7) is characterized in that the step of contacting with a hydrocarbon gas is performed after the step of contacting with an oxidizing gas.

[0032] (9) The method for producing modified recycled carbon black according to (6) or (7), characterized in that the recycled carbon black to which the rubber carbide is attached is a carbon black having a Raman spectrum measured at an excitation wavelength of 532 nm using laser Raman spectroscopy at 1350±20cm -1When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is greater than or equal to 112 and less than or equal to 200.

[0033] (10) A rubber composition comprising:

[0034] Rubber component; and,

[0035] The modified recycled carbon black of (1) is contained in an amount of 1 part by mass or more and 100 parts by mass or less relative to 100 parts by mass of the rubber component.

[0036] Effects of the Invention

[0037] According to the present invention, it is possible to provide recycled carbon black which has a strong bond with a rubber component and has high reinforcing properties for rubber products. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is an explanatory diagram showing a method for calculating the G band intensity when the D band intensity is set to 100 in the modified recycled carbon black of the present invention.

[0039] Figure 2 This is a diagram for explaining the method of measuring the Raman spectrum of the modified recycled carbon black of the present invention.

[0040] Figure 3 This is a Raman spectrum of an example of the morphology of recycled carbon black before modification.

[0041] Figure 4 This is a schematic diagram of an example of a fluidized bed reactor.

[0042] Figure 5 It is a graph showing the relationship between the dynamic storage modulus (E') and the tensile stress (M300) of Examples, Comparative Examples, Reference Examples and rCB1.

[0043] Fig. 6A This is an electron microscope photograph of a sample without using carbon black (SEAST6). Note that the blank area indicates the scale.

[0044] Figure 6B The electron microscope photographs of the recycled carbon black before modification (rCB before modification, rCB1) are shown in FIG.

[0045] Figure 6C This is an electron microscope photograph of modified recycled carbon black (modified rCB Example 7). It should be noted that the blank area represents the scale. DETAILED DESCRIPTION

[0046] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings as appropriate. The following detailed description of the present invention is one example of the embodiments, and the present invention is not to be interpreted as being limited to the embodiments.

[0047] The modified recycled carbon black of the present invention is characterized in that N 2 SA is 50m 2 / g and above and 250m 2 / g or less, in the Raman spectrum measured by laser Raman spectroscopy at an excitation wavelength of 532nm, the -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is greater than or equal to 84 and less than or equal to 111.

[0048] The modified recycled carbon black of the present invention is obtained by modifying the surface of recycled carbon black obtained by thermally cracking rubber products such as waste tires. More specifically, the modified recycled carbon black of the present invention is obtained by removing all or part of the rubber residues mainly composed of rubber carbide attached to the surface of recycled carbon black obtained by thermally cracking rubber products such as waste tires.

[0049] The recycled carbon black with rubber carbide attached to the surface is as follows: In the Raman spectrum obtained by laser Raman spectroscopy at an excitation wavelength of 532 nm, the -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is 112 or more.

[0050] Compared with such recycled carbon black having rubber carbide attached to the surface, the modified recycled carbon black of the present invention has rubber residues mainly composed of rubber carbide attached to the surface removed, so that in the Raman spectrum measured by laser Raman spectroscopy at an excitation wavelength of 532 nm, when the peak intensity of the peak (D band) having a peak top in the range of 1350±20cm-1 is set to 100, the peak intensity of the peak (G band) having a peak top in the range of 1580±20cm-1 (hereinafter, also referred to as the G band intensity when the D band intensity is set to 100) is 84 or more and 111 or less. Since the G band intensity of the recycled carbon black when the D band intensity is set to 100 is within the above range, there is no or very little rubber residue attached to the surface of the recycled carbon black, and the bonding of the recycled carbon black with the rubber component becomes higher, so that the reinforcement of the rubber product becomes higher. The G band strength when the D band strength is set to 100 is preferably 85 or more and 110 or less from the viewpoint of ensuring a moderate bonding strength between the recycled carbon black surface and the rubber, and more preferably 86 or more and 109 or less from the viewpoint of ensuring a stronger bonding strength. On the other hand, if the G band strength when the D band strength of the recycled carbon black is set to 100 exceeds the above range, the rubber residue attached to the surface of the recycled carbon black is large, and the bonding between the recycled carbon black and the rubber component becomes low. In addition, if it is below the above range, the defects of the graphite structure on the surface of the carbon black are large, the surface activity is too high, the aggregation of the carbon blacks in the rubber is promoted, and the reinforcement of the rubber is reduced.

[0051] Figure 1 This is a diagram showing a method for calculating the G band intensity when the D band intensity is set to 100 in the modified recycled carbon black of the present invention.

[0052] like Figure 1 As shown, for the modified recycled carbon black of the present invention, in the Raman spectrum measured by laser Raman spectroscopy at an excitation wavelength of 532 nm, a wavelength of 1350±20cm -1 The peak with a peak top in the range of 1580±20cm (D band) -1 A peak (G band) having a peak top in the range of .

[0053] Then, the peak intensity of the G band was calculated from the peak intensity of the D band and the peak intensity of the G band, with the peak intensity of the D band being 100. According to the research of the present inventors, the greater the amount of rubber carbide attached to the recycled carbon black, the greater the intensity of the G band. Therefore, it can be seen that the removal state of the rubber carbide from the recycled carbon black can be grasped based on the magnitude of the peak intensity of the G band when compared with the peak intensity of the D band.

[0054] In the present invention, the G band intensity when the D band intensity is 100 refers to a value calculated from a Raman spectrum obtained by measuring under the following measurement conditions (1) and performing the data processing (2).

[0055] (1) As a laser Raman spectrometer, HR-800 manufactured by Horiba, Ltd. is used, and a plurality of carbon black samples to be measured are placed on a glass slide, rubbed several times with a spatula to make the surface flat, and measured under the following measurement conditions.

[0056] YAG laser (excitation wavelength): 532nm

[0057] Graduation number: 600gr / mm

[0058] Filter: D0.6

[0059] Objective lens magnification: 100 times

[0060] Exposure time: 150 seconds

[0061] Cumulative times: 2 times

[0062] The spectrum obtained at this time is shown as an example. Figure 2 .

[0063] (2) The measurement wavelength (Raman Shift) of the obtained spectrum was 2100 cm -1 The signal intensity at the point was set to 0, and the average value of each of the 39 adjacent points in the data points constituting the spectrum was calculated. Then, smoothing was performed to obtain a spectrum curve connecting the above average values. Next, in order to facilitate the comparison of each sample, the measurement wavelength was 1350±20cm -1 The peak intensity observed within the range was set to 100.

[0064] The Raman spectrum obtained at this time is as follows: Figure 1 Raman spectrum of the example.

[0065] Figure 1 The Raman spectrum of the modified recycled carbon black of the present invention shows that when the peak intensity of the D band is 100, the peak intensity of the G band is 95, which is in the range of 84 to 111. Figure 3 The Raman spectrum of the morphology example of the recycled carbon black before modification shows that when the peak intensity of the D band is 100, the peak intensity of the G band is 113, which is above 84 and below 111. This shows that Figure 3 In the recycled carbon black before modification shown in FIG. 1 , rubber carbide is attached to the surface. Figure 1 In the modified recycled carbon black shown above, rubber carbonization adhering to the surface is removed by modifying the carbon black.

[0066] The nitrogen adsorption specific surface area N of the modified recycled carbon black of the present invention is 2 SA is 50m 2 / g and above and 250m 2 / g or less. Then use the nitrogen adsorption specific surface area N of carbon black 2 When SA is within the above range, the aggregation force of the recycled carbon black is suppressed to a low level, thereby increasing the reinforcing property of the rubber product. 2 SA, from the viewpoint of dispersibility in the rubber composition, preferably 55m 2 / g or above and 245m 2 / g or less, and more preferably 60 m / g from the viewpoint of the reinforcing property of the rubber composition 2 / g and above and 240m 2 / g or less. On the other hand, the nitrogen adsorption specific surface area N of carbon black is used again. 2 If SA is lower than the above range, the number of bonding points between rubber and recycled carbon black is small and the reinforcement becomes weak. On the other hand, if SA exceeds the above range, the aggregation force of recycled carbon black becomes excessively high, so the reinforcement of rubber products becomes low.

[0067] It should be noted that, in the present invention, the nitrogen adsorption specific surface area N 2 SA is a value measured based on the nitrogen adsorption amount in accordance with the method specified in JIS K6217-2 2017 “Carbon black for rubber - Basic properties - Part 2, Method for determining specific surface area”.

[0068] In terms of dispersibility in the rubber composition, the DBP (dibutylphthalate) absorption of the modified recycled carbon black of the present invention is preferably 60 cm 3 / 100g or more and 200cm 3 / 100g or less, more preferably 70cm 3 / 100g or more and 195cm 3 / 100g or less, more preferably 80cm 3 / 100g or more and 190cm 3 On the other hand, if the DBP absorption is below the above range, the dispersibility of carbon black deteriorates when mixed with the rubber composition, and the reinforcement of the obtained rubber is easily reduced. In addition, if it exceeds the above range, the processability of the rubber obtained when mixed with the rubber composition is sometimes reduced.

[0069] In addition, in the present invention, the DBP absorption refers to a value measured according to the method specified in JIS K6217-4 2017 “Carbon black for rubber - Basic properties - Part 4. Method for determining DBP absorption”.

[0070] The modified recycled carbon black of the present invention is obtained by modifying recycled carbon black obtained by thermal cracking rubber products such as waste tires, and therefore, the ash content of the modified recycled carbon black of the present invention is 3.0% or more and 50.0% or less. Moreover, the ash content of the modified recycled carbon black of the present invention is preferably 4.0% or more and 45.0% or less, and more preferably 5.0% or more and 40.0% or less.

[0071] In the present invention, the ash content refers to a value measured according to the method specified in JIS K6218-2 2005 "Carbon black for rubber - Additional characteristics - Part 2. Method for determining ash content".

[0072] The first embodiment of the method for producing modified recycled carbon black of the present invention is characterized in that it comprises a step (hereinafter also referred to as step A1) of bringing recycled carbon black having rubber carbonized matter attached thereto into contact with an oxidizing gas in a reaction furnace heated to a temperature of not less than 600°C and not more than 1400°C.

[0073] The A1 step is a step in which recycled carbon black with rubber carbide attached thereto is brought into contact with an oxidizing gas in a reaction furnace heated to a specified temperature, thereby oxidizing and decomposing the rubber residue mainly composed of rubber carbide attached to the surface of the recycled carbon black and removing it.

[0074] In the A1 step, the recycled carbon black in contact with the oxidizing gas is obtained by thermally cracking rubber products such as waste tires, and is a carbon black with rubber residues with rubber carbide as the main component attached to the surface. As the recycled carbon black in contact with the oxidizing gas, for example, Enrestec's trade name PB365, Bolder Industries' trade name BolderBlack, Delta Energy's trade name DE-Black, ECOLOMONDO's trade name MondoBlack, etc. can be cited. This recycled carbon black can be manufactured by any manufacturing method without particular limitation, for example, the method described in Patent Document 2 can be cited.

[0075] In the step A1, the recycled carbon black that contacts the oxidizing gas is carbon black that has a Raman spectrum measured at an excitation wavelength of 532 nm using laser Raman spectroscopy at 1350±20 cm -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is 112 or more and 200 or less, preferably 112 or more and 190 or less.

[0076] In the step A1, the ash content of the recycled carbon black that comes into contact with the oxidizing gas is preferably 4.0% to 45.0%, and more preferably 5.0% to 40.0%.

[0077] In step A1, N of recycled carbon black that comes into contact with oxidizing gas 2 SA is 10m 2 / g and above and 200m 2 / g or less, preferably 20m 2 / g and above 190m 2 / g or less, more preferably 25m 2 / g or above and 185m 2 / g or less.

[0078] In the A1 step, the oxidizing gas that contacts the recycled carbon black is oxygen, a gas containing oxygen, air, etc. The contact amount of the oxidizing gas is appropriately selected according to the recycled carbon black to be treated, the amount of adhesion of rubber residues, the type of oxidizing gas used, the specific surface area of ​​the target modified recycled carbon black, etc.

[0079] In the A1 step, the temperature in the reactor when the recycled carbon black is in contact with the oxidizing gas is set to 600° C. to 1400° C., preferably 700° C. to 1300° C., and more preferably 800° C. to 1200° C. When the temperature in the reactor is within the above range, oxidation proceeds appropriately, and removal of rubber residues becomes easy.

[0080] In the A1 step, the temperature in the reaction furnace, the amount of contact with the oxidizing gas, and the time when the recycled carbon black is in contact with the oxidizing gas are set to the G band intensity and N band intensity when the D band intensity is 100. 2 SA is appropriately selected so as to fall within a predetermined range in the modified recycled carbon black of the present invention.

[0081] In the A1 process, recycled carbon black with rubber carbide attached is placed in a reaction furnace, the reaction furnace is heated to a specified temperature, an oxidizing gas is supplied into the reaction furnace, and the decomposition gas is discharged to the outside of the reaction furnace, so that the recycled carbon black with rubber carbide attached is brought into contact with the oxidizing gas at a specified temperature in the reaction furnace, and the rubber residue with rubber carbide as the main component attached to the surface of the recycled carbon black is oxidized, decomposed, and removed.

[0082] For example, the following method can be cited: Figure 4 After recycled carbon black with rubber carbide attached is arranged in a fluidized bed reactor such as the fluidized bed reactor 1 shown in the figure, the fluidized bed reactor is heated to a specified temperature, an oxidizing gas is supplied from the bottom of the fluidized bed reactor, and the gas generated by oxidative decomposition is discharged from the top of the fluidized bed reactor, thereby carrying out the A1 process.

[0083] Figure 4 The fluidized bed reactor 1 shown has a substantially cylindrical shape, and the furnace axis extends in the vertical direction. The fluidized bed reactor 1 has a gas inlet 21 for supplying gas that contacts the carbon black from the lower part of the reactor body 2 to the upper part, and an exhaust port 22 is provided at the upper part of the reactor body 2. Figure 4 As shown, the fluidized bed reactor 1 has a heater coil 3 in which an electric heating wire is spirally wound around the entire outer periphery of the furnace wall of the reactor body 2, and has a structure capable of heating a stirring area 4 provided inside the reactor body 2. In addition, a filter 5 is provided at the inlet of a gas inlet 21 at the lower part of the reactor body 2 so that the carbon black in the reactor body 2 does not leak from the reactor body 2 to the gas inlet 21.

[0084] Furthermore, an oxidizing gas generating gas flow is supplied to the fluidized bed reactor 1. The oxidizing gas is preferably supplied to the fluidized bed reactor 1 in a preheated state. In this case, the preheating temperature is preferably 400°C to 600°C, more preferably 450°C to 600°C, further preferably 450°C to 550°C, further preferably 480°C to 550°C, further preferably 480°C to 520°C. In addition, the oxidizing gas is preferably supplied to the fluidized bed reactor 1 at a temperature of 0.40 Nm / s per 100 g of the recycled carbon black having rubber carbide attached thereto. 3 / hour and above and 3.50Nm 3 / hour or less, more preferably 0.450 Nm 3 / hour or more and 3.45Nm 3 / hour or less, and more preferably 0.50 Nm 3 / hour and above and 3.40Nm 3 / hour or less, and preferably at 0.55 Nm 3 / hour and above and 3.35Nm 3 / hour or less, and more preferably, 0.60 Nm 3 / hour and above and 3.30Nm 3 / hour or less.

[0085] In addition, the oxidizing gas introduced into the fluidized bed reactor 1 is preferably supplied in a manner such that the pressure at the gas inlet port becomes greater than 1.0 MPa and less than 2.0 MPa, more preferably supplied in a manner such that the pressure becomes greater than 1.1 MPa and less than 2.0 MPa, further preferably supplied in a manner such that the pressure becomes greater than 1.1 MPa and less than 1.8 MPa, further preferably supplied in a manner such that the pressure becomes greater than 1.2 MPa and less than 1.8 MPa, and further preferably supplied in a manner such that the pressure becomes greater than 1.2 MPa and less than 1.5 MPa.

[0086] When the fluidized bed reactor 1 is used, the oxidizing gas is supplied from the gas inlet 21. The oxidizing gas may be supplied in a state where the recycled carbon black with the rubber carbonized material attached is introduced into the fluidized bed reactor in advance, or the oxidizing gas may be supplied into the fluidized bed reactor and then the recycled carbon black with the rubber carbonized material attached is introduced from a supply port separately provided in the fluidized bed reactor.

[0087] The recycled carbon black with rubber carbonized matter attached thereto introduced into the fluidized bed reactor 1 is stirred and fluidized under heating by a gas flow of an oxidizing gas. The heating temperature is 600° C. to 1400° C., preferably 700° C. to 1300° C., and more preferably 800° C. to 1200° C. In addition, the stirring and fluidizing time is preferably 100 seconds to 300 seconds, more preferably 110 seconds to 300 seconds, further preferably 110 seconds to 280 seconds, further preferably 120 seconds to 280 seconds, and further preferably 120 seconds to 250 seconds.

[0088] When the fluidized bed reactor 1 is used, after the oxidizing gas is supplied from the gas inlet 21, the recycled carbon black with the rubber carbonized material attached thereto is stirred and mixed in the stirring area 4 heated by the heater coil 3. Under heating, the oxidizing gas is supplied into the furnace, and the recycled carbon black with the rubber carbonized material attached thereto is stirred and flowed by the gas flow of the oxidizing gas, so that the two are brought into contact.

[0089] After stirring with the oxidizing gas, the supply of the oxidizing gas is stopped, and preferably nitrogen is introduced to allow the generated carbon black to cool naturally, thereby stopping the reaction. The nitrogen is preferably introduced into the fluidized bed reactor 1 at a pressure of 6.50 Nm 3 / hour and above and 8.50Nm 3 / hour or less, more preferably 7.00 Nm 3 / hour and above and 8.50Nm 3 / hour or less, and more preferably 7.00 Nm 3 / hour and above and 8.00Nm 3 / hour or less, and preferably at 7.50 Nm3 / hour and above and 8.00Nm 3 / hour or less, and more preferably, 7.50 Nm 3 / hour and above and 7.80Nm 3 / hour or less.

[0090] The cooled carbon black particles are separated and collected using separation and collection devices such as cyclone separators and bag filters, so that the target modified and reused carbon black can be recovered.

[0091] Furthermore, in the method for producing modified recycled carbon black according to the first embodiment of the present invention, N 2 SA is 50m 2 / g and above and 250m 2 / g or less, preferably 55m 2 / g or above and 245m 2 / g or less, more preferably 60m 2 / g and above and 240m 2 / g or less, and in the Raman spectrum obtained by laser Raman spectroscopy at an excitation wavelength of 532nm, the -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 A modified recycled carbon black having a peak top within a range of 84 to 111, preferably 85 to 110, more preferably 86 to 109.

[0092] The second aspect of the method for producing modified recycled carbon black of the present invention is characterized in that it comprises a step of bringing recycled carbon black having rubber carbonized matter attached thereto into contact with an oxidizing gas and a step of bringing recycled carbon black into contact with a hydrocarbon gas in a reaction furnace heated to a temperature of not less than 600° C. and not more than 1400° C.

[0093] As an example of the method for producing modified recycled carbon black according to the second embodiment of the present invention, there can be cited the following method for producing modified recycled carbon black, which comprises the following steps: a step of bringing recycled carbon black having rubber carbonized matter attached thereto into contact with an oxidizing gas in a reaction furnace heated to a temperature of 600° C. or higher and 1400° C. or lower (hereinafter referred to as step A2); and a step of bringing recycled carbon black that has undergone the step of bringing the oxidizing gas into contact with a hydrocarbon gas (step B2). That is, after the step of bringing the oxidizing gas into contact is performed, the step of bringing the hydrocarbon gas into contact is performed.

[0094] The A2 step is a step in which recycled carbon black with rubber carbide attached thereto is brought into contact with an oxidizing gas in a reaction furnace heated to a specified temperature, thereby oxidizing, decomposing and removing the rubber residue composed mainly of rubber carbide attached to the surface of the recycled carbon black.

[0095] In the A2 process, the recycled carbon black in contact with the oxidizing gas is obtained by thermally cracking rubber products such as waste tires, and is a carbon black with rubber residues with rubber carbide as the main component attached to the surface. As the recycled carbon black in contact with the oxidizing gas, for example, Enrestec's trade name PB365, Bolder Industries' trade name BolderBlack, Delta Energy's trade name DE-Black, ECOLOMONDO's trade name MondoBlack, etc. can be cited. This recycled carbon black can be manufactured by any manufacturing method without particular limitation, for example, the method described in Patent Document 2 can be cited.

[0096] In the A2 step, the recycled carbon black that contacts the oxidizing gas is carbon black that has a Raman spectrum measured at an excitation wavelength of 532 nm using laser Raman spectroscopy at 1350±20 cm -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is 112 or more and 200 or less, preferably 112 or more and 190 or less.

[0097] In the step A2, the ash content of the recycled carbon black that comes into contact with the oxidizing gas is preferably 3.0% to 50.0%, and more preferably 4.0% to 45.0%.

[0098] In the A2 step, the oxidizing gas that contacts the recycled carbon black is oxygen, a gas containing oxygen, air, etc. The contact amount of the oxidizing gas is appropriately selected according to the recycled carbon black to be treated, the amount of adhesion of rubber residues, the type of oxidizing gas used, the specific surface area of ​​the target modified recycled carbon black, etc.

[0099] In the A2 step, the temperature in the reaction furnace when the recycled carbon black is in contact with the oxidizing gas is set to 600° C. to 1400° C., preferably 700° C. to 1300° C., and more preferably 800° C. to 1200° C. When the temperature in the reaction furnace is within the above range, oxidation proceeds appropriately, and removal of rubber residues becomes easy.

[0100] In step A2, the conditions such as the temperature in the reaction furnace, the amount of contact with the oxidizing gas, and the time when the recycled carbon black is brought into contact with the oxidizing gas are appropriately selected so that the removal of the rubber residue can be confirmed when observed with a transmission electron microscope or the like.

[0101] In the A2 process, recycled carbon black with rubber carbide attached is placed in a reaction furnace, the reaction furnace is heated to a specified temperature, an oxidizing gas is supplied into the reaction furnace, and the decomposition gas is discharged to the outside of the reaction furnace, so that the recycled carbon black with rubber carbide attached is brought into contact with the oxidizing gas at a specified temperature in the reaction furnace, and the rubber residue with rubber carbide as the main component attached to the surface of the recycled carbon black is oxidized, decomposed, and removed.

[0102] For example, in Figure 4 After recycled carbon black with rubber carbide attached is arranged in a fluidized bed reactor such as the fluidized bed reactor 1 shown, the fluidized bed reactor is heated to a specified temperature, an oxidizing gas is supplied from the bottom of the fluidized bed reactor, and the gas generated by oxidative decomposition is discharged from the top of the fluidized bed reactor, thereby carrying out the A2 process.

[0103] An oxidizing gas is supplied to the fluidized bed reactor 1 to generate a gas flow. The oxidizing gas is preferably supplied to the fluidized bed reactor 1 in a preheated state. In this case, the preheating temperature is preferably 400°C to 600°C, more preferably 450°C to 600°C, further preferably 450°C to 550°C, further preferably 480°C to 550°C, further preferably 480°C to 520°C. In addition, the oxidizing gas is preferably supplied to the fluidized bed reactor 1 at a pressure of 2.50 Nm / s per 100 g of the recycled carbon black to which the rubber carbide is attached. 3 / hour and above and 8.50Nm 3 / hour or less, more preferably 2.55Nm 3 / hour and above and 8.45Nm 3 / hour or less, and more preferably 2.60 Nm 3 / hour and above and 8.40Nm 3 / hour or less, and preferably at 2.65 Nm 3 / hour and above and 8.35Nm 3 / hour or less, and more preferably, 2.70 Nm 3 / hour and above and 8.30Nm 3 / hour or less.

[0104] In addition, the oxidizing gas introduced into the fluidized bed reactor 1 is preferably supplied in a manner such that the pressure at the gas inlet port becomes greater than 1.0 MPa and less than 2.0 MPa, more preferably supplied in a manner such that the pressure becomes greater than 1.1 MPa and less than 2.0 MPa, further preferably supplied in a manner such that the pressure becomes greater than 1.1 MPa and less than 1.8 MPa, further preferably supplied in a manner such that the pressure becomes greater than 1.2 MPa and less than 1.8 MPa, and further preferably supplied in a manner such that the pressure becomes greater than 1.2 MPa and less than 1.5 MPa.

[0105] When the fluidized bed reactor 1 is used, the oxidizing gas is supplied from the gas inlet 21. The oxidizing gas may be supplied in a state where the recycled carbon black with the rubber carbonized material attached is introduced into the reactor in advance, or the oxidizing gas may be supplied into the reactor and then the recycled carbon black with the rubber carbonized material attached is introduced from a supply port separately provided in the reactor.

[0106] The recycled carbon black with rubber carbonized matter attached thereto introduced into the fluidized bed reactor 1 is stirred and flowed under heating by a gas flow of an oxidizing gas. The heating temperature is 600° C. to 1400° C., preferably 700° C. to 1300° C., and more preferably 800° C. to 1200° C. In addition, the stirring and flowing time is preferably 100 seconds to 300 seconds, more preferably 110 seconds to 300 seconds, further preferably 110 seconds to 280 seconds, further preferably 120 seconds to 280 seconds, and further preferably 120 seconds to 250 seconds.

[0107] When the fluidized bed reactor 1 is used, after the oxidizing gas is supplied from the gas inlet 21, the recycled carbon black with the rubber carbonized material attached thereto is stirred and mixed in the stirring area 4 heated by the heater coil 3. The oxidizing gas is supplied into the furnace under heating, and the recycled carbon black with the rubber carbonized material attached thereto is stirred and flowed by the gas flow of the oxidizing gas, so that the two are brought into contact.

[0108] The B2 process is the following process: the recycled carbon black that has undergone the A2 process in a reaction furnace heated to a specified temperature is brought into contact with a hydrocarbon gas, thereby filling the pores formed on the surface of the recycled carbon black with carbides generated by thermal cracking of the hydrocarbon gas, thereby reducing the specific surface area of ​​the recycled carbon black.

[0109] In the B2 step, the hydrocarbon gas that contacts the recycled carbon black after the A2 step is not particularly limited as long as it is heated at a predetermined temperature in a reactor to cause thermal cracking and generate carbides, and examples thereof include methane gas, ethane gas, propane gas, butane gas, etc. The contact amount of the hydrocarbon gas is appropriately selected depending on the specific surface area of ​​the recycled carbon black to be treated, the type of hydrocarbon gas used, the specific surface area of ​​the target modified recycled carbon black, etc.

[0110] In step B2, the temperature in the reactor when the recycled carbon black is in contact with the hydrocarbon gas is set to 600°C or higher and 1400°C or lower, preferably 700°C or higher and 1300°C or lower, and more preferably 800°C or higher and 1200°C or lower. When the temperature in the reactor is within the above range, the hydrocarbon gas is adsorbed on the pores with a diameter of several nanometers or less existing on the surface of the recycled carbon black and carbonized, thereby increasing the specific surface area N 2 SA decreased moderately.

[0111] In step B2, the temperature in the reactor, the amount of contact with hydrocarbon gas, and the time when the recycled carbon black is contacted with the hydrocarbon gas are set to N 2 SA is appropriately selected so as to fall within a predetermined range in the modified recycled carbon black of the present invention.

[0112] In the B2 process, the recycled carbon black that has undergone the A2 process is placed in a reactor, the reactor is heated to a specified temperature, hydrocarbon gas is supplied into the reactor, and the reaction gas is discharged to the outside of the reactor, so that the recycled carbon black that has undergone the A2 process comes into contact with the hydrocarbon gas at a specified temperature in the reactor to generate carbide, which fills the pores formed on the surface of the recycled carbon black.

[0113] For example, in Figure 4 In a fluidized bed reactor such as the fluidized bed reactor 1 shown in the figure, the recycled carbon black after the A2 process is configured, the fluidized bed reactor is heated to a specified temperature, hydrocarbon gas is supplied from the lower part of the fluidized bed reactor, and the reaction gas is discharged from the upper part of the fluidized bed reactor, thereby carrying out the B2 process.

[0114] A hydrocarbon gas generating gas flow is supplied to the fluidized bed reactor 1. The hydrocarbon gas is preferably supplied to the fluidized bed reactor 1 in a preheated state. In this case, the preheating temperature is preferably 400°C to 600°C, more preferably 450°C to 600°C, further preferably 450°C to 550°C, further preferably 480°C to 550°C, further preferably 480°C to 520°C. In addition, the hydrocarbon gas is preferably 0.30 Nm / s per 100 g of the recycled carbon black after the A2 step in the fluidized bed reactor 1. 3 / hour or more and 3.00Nm 3 / hour or less, more preferably 0.35Nm 3 / hour and above and 2.95Nm 3 / hour or less, and more preferably 0.40 Nm 3 / hour and above and 2.90Nm 3 / hour or less, and preferably at 0.45 Nm3 / hour and above and 2.85Nm 3 / hour or less, and more preferably, 0.50 Nm 3 / hour and above and 2.80Nm 3 / hour or less.

[0115] In addition, the hydrocarbon gas introduced into the fluidized bed reactor 1 is preferably supplied in a manner such that the pressure at the gas inlet port becomes greater than 1.0 MPa and less than 2.0 MPa, more preferably supplied in a manner such that the pressure becomes greater than 1.1 MPa and less than 2.0 MPa, further preferably supplied in a manner such that the pressure becomes greater than 1.1 MPa and less than 1.8 MPa, further preferably supplied in a manner such that the pressure becomes greater than 1.2 MPa and less than 1.8 MPa, and further preferably supplied in a manner such that the pressure becomes greater than 1.2 MPa and less than 1.5 MPa.

[0116] When the fluidized bed reactor 1 is used, hydrocarbon gas is supplied from the gas inlet 21. The hydrocarbon gas may be supplied in a state where the recycled carbon black after the A2 step is previously introduced into the fluidized bed reactor, or the recycled carbon black after the A2 step may be introduced from a supply port separately provided in the fluidized bed reactor after the hydrocarbon gas is supplied into the fluidized bed reactor.

[0117] The recycled carbon black after the A2 step introduced into the fluidized bed reactor 1 is stirred and flowed under heating by the gas flow of hydrocarbon gas. The heating temperature is 600° C. to 1400° C., preferably 700° C. to 1300° C., more preferably 800° C. to 1200° C. In addition, the stirring and flowing time is preferably 100 seconds to 300 seconds, more preferably 110 seconds to 300 seconds, further preferably 110 seconds to 280 seconds, further preferably 120 seconds to 280 seconds, and further preferably 120 seconds to 250 seconds.

[0118] When the fluidized bed reactor 1 is used, after hydrocarbon gas is supplied from the gas inlet 21, the recycled carbon black after the A2 process is stirred and mixed in the stirring area 4 heated by the heater coil 3. Hydrocarbon gas is supplied into the furnace under heating, and the recycled carbon black after the A2 process is stirred and flowed by the gas flow of the hydrocarbon gas, so that the two are in contact.

[0119] After the stirring based on the hydrocarbon gas, the supply of the hydrocarbon gas is stopped, and preferably nitrogen is introduced to allow the generated carbon black to cool naturally, thereby stopping the reaction. The nitrogen gas is preferably introduced into the fluidized bed reactor 1 at a pressure of 6.50 Nm 3 / hour and above and 8.50Nm 3 / hour or less, more preferably 7.00 Nm 3 / hour and above and 8.50Nm 3 / hour or less, and more preferably 7.00 Nm 3 / hour and above and 8.00Nm 3 / hour or less, and preferably at 7.50 Nm 3 / hour and above and 8.00Nm 3 / hour or less, and more preferably, 7.50 Nm 3 / hour and above and 7.80Nm 3 / hour or less.

[0120] The cooled carbon black particles are separated and collected using separation and collection devices such as cyclone separators and bag filters, so that the target modified and reused carbon black can be recovered.

[0121] As an example of the second embodiment of the method for producing modified recycled carbon black of the present invention, the following method for producing modified recycled carbon black can be cited: the method comprises a step (hereinafter referred to as step C2) of bringing recycled carbon black having rubber carbide attached thereto into contact with an oxidizing gas and a hydrocarbon gas in a reaction furnace heated to a temperature of above 600°C and below 1400°C.

[0122] The C2 process is as follows: in a reaction furnace heated to a specified temperature, the recycled carbon black with rubber carbide attached to it is brought into contact with an oxidizing gas and a hydrocarbon gas, thereby oxidizing, decomposing and removing the rubber residue composed mainly of rubber carbide attached to the surface of the recycled carbon black, and further, bringing the recycled carbon black composed mainly of rubber carbide from which the rubber residue has been removed into contact with a hydrocarbon gas, thereby filling the pores formed on the surface of the recycled carbon black with carbides generated by thermal cracking of the hydrocarbon gas, thereby reducing the specific surface area of ​​the recycled carbon black.

[0123] In the C2 process, the recycled carbon black in contact with the oxidizing gas and the hydrocarbon gas is obtained by thermally cracking rubber products such as waste tires, and is a carbon black with rubber residues with rubber carbide as the main component attached to the surface. As the recycled carbon black in contact with the oxidizing gas and the hydrocarbon gas, for example, Enrestec's product name PB365, Bolder Industries' product name BolderBlack, Delta Energy's product name DE-Black, ECOLOMONDO's product name MondoBlack, etc. can be cited. This recycled carbon black can be manufactured by any manufacturing method without particular limitation, for example, the method described in Patent Document 2 can be cited.

[0124] In the C2 step, the recycled carbon black that comes into contact with the oxidizing gas and the hydrocarbon gas is a carbon black that has a Raman spectrum measured at an excitation wavelength of 532 nm using laser Raman spectroscopy at 1350±20cm -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is 112 or more and 200 or less, preferably 112 or more and 190 or less.

[0125] In the step C2, the ash content of the recycled carbon black that comes into contact with the oxidizing gas is preferably 3.0% to 50.0%, and more preferably 5.0% to 45.0%.

[0126] In the C2 process, the oxidizing gas in contact with the recycled carbon black is oxygen, a gas containing oxygen, air, etc. In addition, in the C2 process, the hydrocarbon gas in contact with the recycled carbon black is not particularly limited as long as it is heated at a specified temperature in the reactor to cause thermal cracking and generate carbides. For example, methane gas, ethane gas, propane gas, butane gas, etc. can be cited. The contact amount of the oxidizing gas is appropriately selected according to the recycled carbon black to be treated, the amount of adhesion of rubber residues, the type of oxidizing gas used, the specific surface area of ​​the target modified recycled carbon black, etc. In addition, the contact amount of the hydrocarbon gas is appropriately selected according to the specific surface area of ​​the recycled carbon black to be treated, the type of hydrocarbon gas used, the specific surface area of ​​the target modified recycled carbon black, etc.

[0127] In step C2, the temperature in the reactor when the recycled carbon black is brought into contact with the oxidizing gas and the hydrocarbon gas is 600°C to 1400°C, preferably 700°C to 1300°C, more preferably 800°C to 1200°C. When the temperature in the reactor is in the above range, the hydrocarbon gas is adsorbed on the pores with a diameter of several nanometers or less existing on the surface of the recycled carbon black and carbonized, thereby increasing the specific surface area N 2 SA decreased moderately.

[0128] In the C2 step, the temperature in the reactor when the recycled carbon black is in contact with the oxidizing gas and the hydrocarbon gas, the contact amount and time of the oxidizing gas and the hydrocarbon gas are set to the G band intensity and N band intensity when the D band intensity is 100. 2 SA is appropriately selected so as to fall within a predetermined range in the modified recycled carbon black of the present invention.

[0129] In the C2 process, recycled carbon black with rubber carbide attached is placed in a reactor, the reactor is heated to a specified temperature, an oxidizing gas and a hydrocarbon gas are supplied into the reactor, and the decomposition gas and the reaction gas are discharged to the outside of the reactor, so that the recycled carbon black with rubber carbide attached is brought into contact with the oxidizing gas at a specified temperature in the reactor, the rubber residue composed mainly of rubber carbide attached to the surface of the recycled carbon black is oxidized, decomposed and removed, and the recycled carbon black with rubber carbide as the main component and the rubber residue removed is brought into contact with the hydrocarbon gas, so that the pores formed on the surface of the recycled carbon black are filled with carbides generated by thermal cracking of the hydrocarbon gas, thereby reducing the specific surface area of ​​the recycled carbon black.

[0130] For example, in Figure 4 After recycled carbon black with rubber carbide attached is arranged in a fluidized bed reactor such as the fluidized bed reactor 1 shown in the figure, the fluidized bed reactor is heated to a specified temperature, an oxidizing gas and a hydrocarbon gas are supplied from the lower part of the fluidized bed reactor, and a decomposition gas oxidized and decomposed by the oxidizing gas and a reaction gas produced by thermal cracking of the hydrocarbon gas are discharged from the upper part of the fluidized bed reactor, thereby carrying out the C2 process.

[0131] An oxidizing gas and a hydrocarbon gas are simultaneously supplied to the fluidized bed reactor 1 to generate a gas flow. The oxidizing gas and the hydrocarbon gas are preferably supplied to the fluidized bed reactor 1 in a preheated state. In this case, the preheating temperature is preferably 400°C to 600°C, more preferably 450°C to 600°C, further preferably 450°C to 550°C, further preferably 480°C to 550°C, further preferably 480°C to 520°C. In addition, the oxidizing gas and the hydrocarbon gas are preferably supplied to the fluidized bed reactor 1 at a pressure of 2.50 Nm / s for every 100 g of the recycled carbon black having the rubber carbide attached thereto. 3 / hour and above and 8.50Nm 3 / hour or less, and more preferably, 2.55 Nm 3 / hour and above and 8.45Nm 3 / hour or less, and more preferably 2.60 Nm 3 / hour and above and 8.40Nm 3 / hour or less, and preferably at 2.65 Nm 3 / hour and above and 8.35Nm 3 / hour or less, and more preferably, 2.70 Nm 3 / hour and above and 8.30Nm 3 / hour or less, and preferably to the fluidized bed reactor 1 at a rate of 0.30 Nm 3 / hour or more and 3.00Nm3 The hydrocarbon gas is supplied at a rate of less than 0.35 Nm / h. 3 / hour and above and 2.95Nm 3 / hour or less, and more preferably 0.40 Nm 3 / hour and above and 2.90Nm 3 / hour or less, and preferably at 0.45 Nm 3 / hour and above and 2.85Nm 3 / hour or less, and more preferably, 0.50 Nm 3 / hour and above and 2.80Nm 3 / hour or less.

[0132] In addition, the oxidizing gas and hydrocarbon gas introduced into the fluidized bed reactor 1 are preferably supplied in a manner such that the pressure at the gas inlet port is greater than 1.0 MPa and less than 2.0 MPa, more preferably greater than 1.1 MPa and less than 2.0 MPa, further preferably greater than 1.1 MPa and less than 1.8 MPa, further preferably greater than 1.2 MPa and less than 1.8 MPa, and even more preferably greater than 1.2 MPa and less than 1.5 MPa.

[0133] When the fluidized bed reactor 1 is used, the oxidizing gas and the hydrocarbon gas are supplied from the gas inlet port 21. The oxidizing gas may be supplied in a state where the recycled carbon black with the rubber carbonized material attached is introduced into the reactor in advance, or the oxidizing gas and the hydrocarbon gas may be supplied into the fluidized bed reactor and then the recycled carbon black with the rubber carbonized material attached is introduced from a supply port separately provided in the fluidized bed reactor.

[0134] The recycled carbon black with rubber carbonized material attached introduced into the fluidized bed reactor 1 is stirred and flowed under heating by the gas flow of oxidizing gas and hydrocarbon gas. The heating temperature is 600° C. to 1400° C., preferably 700° C. to 1300° C., more preferably 800° C. to 1200° C. In addition, the stirring and flowing time is preferably 100 seconds to 300 seconds, more preferably 110 seconds to 300 seconds, further preferably 110 seconds to 280 seconds, further preferably 120 seconds to 280 seconds, and further preferably 120 seconds to 250 seconds.

[0135] When the fluidized bed reactor 1 is used, after the oxidizing gas and hydrocarbon gas are supplied from the gas inlet 21, the recycled carbon black with the rubber carbonized material attached thereto is stirred and mixed in the stirring area 4 heated by the heater coil 3. The oxidizing gas and hydrocarbon gas are supplied into the furnace under heating, and the recycled carbon black with the rubber carbonized material attached thereto is stirred and flowed by the gas flow of the oxidizing gas and hydrocarbon gas, thereby bringing the two into contact.

[0136] After the oxidizing gas and the hydrocarbon gas are stirred, the supply of the oxidizing gas and the hydrocarbon gas is stopped, and preferably nitrogen is introduced to allow the generated carbon black to cool naturally, thereby stopping the reaction. The nitrogen is preferably introduced into the fluidized bed reactor 1 at a pressure of 6.50 Nm 3 / hour and above and 8.50Nm 3 / hour or less, more preferably 7.00 Nm 3 / hour and above and 8.50Nm 3 / hour or less, and more preferably 7.00 Nm 3 / hour and above and 8.00Nm 3 / hour or less, and preferably at 7.50 Nm 3 / hour and above and 8.00Nm 3 / hour or less, and more preferably, 7.50 Nm 3 / hour and above and 7.80Nm 3 / hour or less.

[0137] The cooled carbon black particles are separated and collected using separation and collection devices such as cyclone separators and bag filters, so that the target modified and reused carbon black can be recovered.

[0138] In the method for producing modified recycled carbon black according to the second embodiment of the present invention, N 2 SA is 50m 2 / g and above and 250m 2 / g or less, preferably 55m 2 / g or above and 245m 2 / g or less, more preferably 60m 2 / g and above and 240m 2 / g or less, and in the Raman spectrum obtained by laser Raman spectroscopy at an excitation wavelength of 532nm, the -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1A modified recycled carbon black having a peak top within a range of 84 to 111, preferably 85 to 110, more preferably 86 to 109.

[0139] The first embodiment of the present invention is a method for producing modified recycled carbon black as follows: according to step A1, a rubber residue mainly composed of rubber carbides attached to recycled carbon black to which rubber carbides are attached is oxidized and decomposed, so that the G band strength and N band strength of the recycled carbon black when the D band strength is 100 are reduced to 0. 2 Both SA are limit values ​​for the modified recycled carbon black of the present invention.

[0140] An example of a method for producing a modified recycled carbon black according to the second embodiment of the present invention is as follows: According to step A2, under the oxidative decomposition of the rubber residue containing rubber carbide as the main component attached to the recycled carbon black to which rubber carbide is attached, the G band strength of the recycled carbon black when the D band strength is set to 100 can be made the limit value of the modified recycled carbon black of the present invention, but as the oxidation progresses, many pores are formed in the recycled carbon black, and therefore, N 2 When SA is greater than the limit value of the modified recycled carbon black of the present invention, the B2 step is performed to fill the pores with carbides, thereby making N 2 SA is the limit value of the modified recycled carbon black of the present invention. Alternatively, an example of the method for producing the modified recycled carbon black of the second embodiment of the present invention is as follows: according to the A2 step, under the oxidative decomposition of the rubber residue containing rubber carbide as the main component attached to the recycled carbon black to which the rubber carbide is attached, the G band strength and N band strength of the recycled carbon black when the D band strength is set to 100 can be reduced to 2 SA is the limit value of the modified recycled carbon black of the present invention, but if you want to adjust N 2 In the case of SA, the B2 step is performed to fill the pores with carbides, thereby adjusting N within the range of the limit value of the modified recycled carbon black of the present invention. 2 SA.

[0141] An example of a method for producing a modified recycled carbon black according to the second embodiment of the present invention is as follows: According to the C2 step, under the oxidative decomposition of the rubber residue containing rubber carbide as the main component attached to the recycled carbon black to which rubber carbide is attached, the G band strength of the recycled carbon black when the D band strength is set to 100 can be made the limit value of the modified recycled carbon black of the present invention, but as the oxidation progresses, many pores are formed in the recycled carbon black, and therefore, N 2 SA is greater than the limit value of the modified recycled carbon black of the present invention, or if you want to adjust N 2 In the case of SA, oil carbides fill the holes in the C2 process, thereby making N 2SA is a limit value of the modified recycled carbon black of the present invention, or is adjusted within the range of the limit value.

[0142] The modified recycled carbon black of the first embodiment of the present invention is characterized in that it is obtained by contacting the recycled carbon black with rubber carbonized matter attached thereto with an oxidizing gas in a reaction furnace heated to 600° C. or higher and 1400° C. or lower. 2 SA is 50m 2 / g and above and 250m 2 / g or less, preferably 55m 2 / g or above and 245m 2 / g or less, more preferably 60m 2 / g and above and 240m 2 / g or less, in the Raman spectrum measured by laser Raman spectroscopy at an excitation wavelength of 532nm, the -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is 84 or more and 111 or less, preferably 85 or more and 110 or less, and more preferably 86 or more and 109 or less.

[0143] The process of bringing recycled carbon black having rubber carbonized matter attached thereto into contact with an oxidizing gas in a reaction furnace heated to a temperature between 600° C. and 1400° C. in the first embodiment of the modified recycled carbon black of the present invention is the same as the A1 process of the method for producing modified recycled carbon black of the first embodiment of the present invention.

[0144] The modified recycled carbon black of the second embodiment of the present invention is characterized in that it is obtained by contacting the recycled carbon black with rubber carbonized matter with an oxidizing gas and a hydrocarbon gas in a reaction furnace heated to 600° C. or higher and 1400° C. or lower. 2 SA is 50m 2 / g and above and 250m 2 / g or less, preferably 55m 2 / g or above and 245m 2 / g or less, more preferably 60m 2 / g and above and 240m 2 / g or less, in the Raman spectrum measured by laser Raman spectroscopy at an excitation wavelength of 532nm, the -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1The peak intensity of the peak having a peak top in the range of is 84 or more and 111 or less, preferably 85 or more and 110 or less, and more preferably 86 or more and 109 or less.

[0145] As an example of the second embodiment of the modified recycled carbon black of the present invention, there can be cited the following modified recycled carbon black, which is obtained by a process of bringing recycled carbon black having rubber carbide attached thereto into contact with an oxidizing gas in a reaction furnace heated to a temperature of not less than 600°C and not more than 1400°C (hereinafter referred to as process A2), and a process of bringing the recycled carbon black having undergone the process of bringing the oxidizing gas into contact with a hydrocarbon gas (process B2).

[0146] As an example of the second embodiment of the modified recycled carbon black of the present invention, there can be cited the following modified recycled carbon black, which is obtained by a process (hereinafter referred to as C2 process) in which recycled carbon black having rubber carbide attached thereto is brought into contact with an oxidizing gas and a hydrocarbon gas in a reaction furnace heated to a temperature of above 600°C and below 1400°C.

[0147] The A2 step, the B2 step, and the C2 step of the modified and recycled carbon black according to the second embodiment of the present invention are the same as the A2 step, the B2 step, and the C2 step of the method for producing the modified and recycled carbon black according to the second embodiment of the present invention.

[0148] The modified recycled carbon black of the present invention, the modified recycled carbon black obtained by the first method for producing modified recycled carbon black of the present invention, and the modified recycled carbon black obtained by the second method for producing modified recycled carbon black of the present invention have no rubber residue with rubber carbide as the main component attached, or even if there is attachment, the amount is very small, and the aggregation is suppressed to a low level. Therefore, the bonding with the rubber component can be enhanced to the same extent as carbon black that has never been used as a tire filler, and the reinforcement of rubber products can be improved.

[0149] The rubber composition of the present invention is characterized by comprising:

[0150] Rubber components; and

[0151] The modified recycled carbon black of the present invention is in an amount of 1 part by mass or more and 100 parts by mass or less relative to 100 parts by mass of the rubber component.

[0152] In the rubber composition of the present invention, the rubber component may be at least one selected from diene rubbers such as natural rubber, styrene-butadiene rubber, polybutadiene rubber, isoprene rubber, butyl rubber, chloroprene rubber, and acrylonitrile-butadiene copolymer rubber.

[0153] The rubber composition of the present invention contains the modified recycled carbon black of the present invention. The details of the modified recycled carbon black of the present invention contained in the rubber composition are as described above.

[0154] Moreover, the modified recycled carbon black of the present invention is one in which the rubber residue mainly composed of rubber carbide attached to the surface of the recycled carbon black is removed and the aggregation is suppressed to a lower level. Therefore, the bond with the rubber component is strong, and therefore the reinforcement of the rubber composition is high. Therefore, the strength of the rubber composition of the present invention is high.

[0155] In the rubber composition of the present invention, the content ratio of the modified recycled carbon black of the present invention is 1 mass part or more and 100 mass parts or less relative to 100 mass parts of the rubber component, preferably 10 mass parts or more and 80 mass parts or less relative to 100 mass parts of the rubber component, and more preferably 15 mass parts or more and 70 mass parts or less relative to 100 mass parts of the rubber component. In the rubber composition of the present invention, the content ratio of the modified recycled carbon black of the present invention is within the above range, so that a rubber composition with high strength can be obtained.

[0156] In addition, the rubber composition of the present invention may also contain necessary components such as commonly used inorganic reinforcing materials, silane coupling agents, vulcanizing agents, vulcanization accelerators, antioxidants, vulcanization aids, softeners, plasticizers, etc. The rubber composition of the present invention preferably contains these components in an amount of 1% by mass or more and 40% by mass or less, more preferably 2% by mass or more and 30% by mass or less, and further preferably 3% by mass or more and 25% by mass or less in total.

[0157] The rubber composition of the present invention can be obtained by kneading a predetermined amount of the modified recycled carbon black of the present invention and a desired amount of an inorganic reinforcing material, a silane coupling agent, a vulcanizing agent, a vulcanization accelerator, an antioxidant, a vulcanization aid, a softener, a plasticizer, etc. with a rubber component as required. The kneading can be performed using a known mixer, a mill, or other kneading machine.

[0158] After the rubber composition of the present invention is molded into a predetermined shape, it is preferably heated and cured at 130 to 180° C. to obtain a desired rubber molded product.

[0159] Example

[0160] The invention is illustrated by the following examples.

[0161] (Examples 1 to 9, Comparative Examples 1 to 6)

[0162] exist Figure 4In the fluidized bed reactor shown in Table 1, 100 g of the recycled carbon black (before modification) to be treated is placed, and a contact process with an oxidizing gas (process 1) and / or a contact process with a hydrocarbon gas (process 2) are performed under the conditions shown in Table 1 to obtain modified recycled carbon black. It should be noted that when both process 1 and process 2 are performed, in Examples 1 to 8 and Comparative Examples 1 to 6, process 2 is performed after process 1 is performed. In addition, in Example 9, an oxidizing gas and a hydrocarbon gas are supplied simultaneously, and process 1 and process 2 are performed simultaneously.

[0163] (Reference Examples 1-2)

[0164] As unused carbon black, unused products of commercially available SEAST3 (reference example 1) and SEAST6 (reference example 2) were used.

[0165] Next, the nitrogen adsorption specific surface area N of the recycled carbon black before modification, the modified recycled carbon black obtained, and the unused carbon black was measured. 2 SA, G band intensity when D band intensity is set to 100. The results are shown in Table 2. In addition, electron microscope photographs of unused carbon black (SEAST6), recycled carbon black before modification (rCB before modification rCB1) and modified recycled carbon black (rCB after modification Example 7) obtained by electron microscope observation are shown in Table 2. Fig. 6A , 6B , 6C.

[0166] Next, as shown in Table 3, 100 parts by mass of natural rubber (RSS#1) as a rubber component, any modified recycled carbon black obtained in the above Examples and Comparative Examples, 45 parts by mass of recycled carbon black before modification or unused carbon black, 3 parts by mass of stearic acid, 1 part by mass of an antioxidant (Antage 6C manufactured by Kawaguchi Chemical Co., Ltd.), and 4 parts by mass of zinc flower were kneaded in a closed mixer (MIXTRON BB-2 manufactured by Kobe Steel, Ltd.), and then 0.5 parts by mass of a vulcanization accelerator (Accel NS manufactured by Kawaguchi Chemical Co., Ltd.) and 1.5 parts by mass of sulfur were kneaded into the obtained kneaded product using an open roll to obtain a rubber composition.

[0167] Next, each of the obtained rubber compositions was vulcanized at a temperature of 145° C. for 35 minutes to obtain a vulcanized rubber.

[0168] The obtained vulcanized rubber was used to measure the dynamic storage modulus (E') and tensile stress (M300) according to the method shown below. The results are shown in Table 2. In addition, the relationship between the dynamic storage modulus (E') and tensile stress (M300) of the examples, comparative examples and the ones not using carbon black is shown in Table 2. Figure 5 .

[0169] Recycled carbon black 1 (rCB1)

[0170] Recycled carbon black obtained by thermal cracking of waste tires

[0171] Enrestec, PB365,

[0172] Ash content: 18.6%,

[0173] G band intensity when D band intensity is set to 100: 113

[0174] N 2 SA: 78m 2 / g

[0175] Oxidizing gas: air

[0176] Hydrocarbon gas: methane gas

[0177] <Measurement of (dynamic storage modulus) (E')>

[0178] Using test pieces having a thickness of 2 mm, a length of 35 mm, and a width of 5 mm cut out from each of the obtained vulcanized rubbers, the dynamic storage modulus (E') was measured using a fully automatic viscoelasticity analyzer (VR-7130 manufactured by Ueshima Seisakusho Co., Ltd.) in accordance with JIS K6394 2007 "Vulcanized rubber and thermoplastic rubber - Methods for determining dynamic properties - General guidelines" under the measurement conditions of a frequency of 50 Hz, a dynamic strain rate of 1.26%, and a measurement temperature of 60°C.

[0179] <Measurement of (tensile stress) (M300)>

[0180] Using a JIS dumbbell No. 3 test piece cut out from each of the obtained vulcanized rubbers, the stress at an elongation of 300% was measured using Strograph AE-CT manufactured by Toyo Seiki Co., Ltd. in accordance with JIS K6251 2017 “Rubber vulcanized and thermoplastic rubber—Method for determining tensile properties”.

[0181] [Table 1]

[0182]

[0183] [Table 2]

[0184]

[0185] [Table 3]

[0186]

[0187] The E' of Examples 1 to 9 is as high as 4.7 MPa or more. On the other hand, the E' of rCB1 and Comparative Examples 1 to 6 is as low as 4.0 MPa or less. This shows that the modified recycled carbon black of Examples 1 to 9 has a strong bond with the rubber component and can improve the reinforcement of the rubber composition.

[0188] In addition, M300 of Examples 1 to 9 is as high as 100 kgf / cm 2 From the above, it can be seen that M300 can also be improved.

[0189] Industrial Applicability

[0190] According to the present invention, a new type of recycled carbon black can be provided which has a strong bond with the rubber component and a high reinforcing property for rubber products. Therefore, by using the recycled carbon black obtained by thermal cracking rubber products such as waste tires, rubber products having the same performance as unused carbon black can be manufactured.

[0191] Description of Reference Numerals

[0192] 1Fluidized bed reactor

[0193] 2 Reactor body

[0194] 3 Heater Coils

[0195] 4 Mixing area

[0196] 5 Filters

[0197] 21 Gas inlet

[0198] 22 Exhaust port

Claims

1. A modified recycled carbon black, characterized in that: The carbon black is obtained by contacting recycled carbon black with rubber carbonized matter with an oxidizing gas in a reaction furnace heated to 800°C or higher and 1400°C or lower. The N2SA of the modified recycled carbon black is 50m 2 / g and above and 250m 2 / g or less, In the Raman spectrum measured by laser Raman spectroscopy at an excitation wavelength of 532 nm, the -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is greater than or equal to 84 and less than or equal to 111.

2. A modified recycled carbon black, characterized in that: The method is obtained by contacting recycled carbon black with rubber carbonized matter with an oxidizing gas and a hydrocarbon gas in a reaction furnace heated to 800° C. or higher and 1400° C. or lower. The N2SA of the modified recycled carbon black is 50m 2 / g and above and 250m 2 / g or less, In the Raman spectrum measured by laser Raman spectroscopy at an excitation wavelength of 532 nm, the -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is greater than or equal to 84 and less than or equal to 111.

3. The modified recycled carbon black according to claim 1 or 2, characterized in that: The recycled carbon black with rubber carbide attached thereto is carbon black having a Raman spectrum measured at an excitation wavelength of 532 nm using laser Raman spectroscopy, with a wavelength of 1350±20 cm -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is greater than or equal to 112 and less than or equal to 200.

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