Method for producing additive material for rubber tire

Abstract

To provide a method for producing an additive material for rubber tires capable of contributing to CO2 emission reduction through the use of an additive material prepared from plant-based raw materials, while allowing reduction in manufacturing cost and the like.SOLUTION: The method for producing an additive material for rubber tires comprises a mixing step (S2) of mixing a first plant-derived raw material (11) having a silica content of 10% or more in the plant-derived raw material and a second plant-derived raw material (12) having a silica content of 10% or less in the plant-derived raw material, a pulverizing step (S3) of pulverizing the plant-derived raw materials, and a carbonizing step (S4) of heating and carbonizing the plant-derived raw materials (11, 12) obtained through the pulverizing step.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing carbon and silicon dioxide, which are additive materials for rubber tires, produced using plant-based raw materials. [Background technology]

[0002] Plant-derived raw materials have traditionally been used for battery materials, conductive materials, heating elements, tires, building materials, etc. from the perspective of carbon neutrality. In particular, carbon materials with a large specific surface area have been used as materials for batteries and capacitors. Carbon materials with excellent electrical conductivity have also been widely used as heating materials and shielding materials.

[0003] As described above, various inventions have been proposed as methods for producing carbon materials from plant raw materials. For example, Patent Document 1 describes a method for producing a carbon material, in which a carbonaceous raw material is activated with an alkali metal compound to obtain activated carbon or activated carbon fiber with a high specific surface area, by surrounding the reaction system (a composition containing the carbonaceous raw material and the alkali metal compound) with a carbon-based powder layer and, if necessary, further including an inorganic compound layer in the carbon-based powder layer for activation. It also describes a method for producing a carbon material in which the temperature rise rate during activation is set to 20°C / hr or less, thereby increasing the yield of the carbon material per container. An electric double layer capacitor uses the activated carbon or activated carbon fiber obtained by this production method as an electrode material.

[0004] For example, Patent Document 2 discloses an invention relating to a cap tread for passenger car tires that uses silica produced from plant-derived raw materials and has a rubber composition A phase and a rubber composition B phase that are mutually independent and have a boundary therebetween, wherein the rubber composition A phase contains 100 parts by mass or more of silica and 10 parts by mass or less of carbon black per 100 parts by mass of the rubber component, and the rubber composition B phase contains 10 parts by mass or more of carbon black and 13 to 20 parts by mass of silica per 100 parts by mass of the rubber component, and the rubber composition B phase is separated from the rubber composition A phase and exists independently within the rubber composition A phase. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-362915 [Patent Document 2] Japanese Patent Publication No. 2022-179157 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0006] As shown in the patent document, many types of additive materials are used in tire materials, which means that if the manufacturing cost of each material increases, the unit price of the tire itself also increases.

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a method for producing additive materials for rubber tires that can contribute to reducing CO2 emissions by using additive materials produced from plant-based raw materials and that can also reduce manufacturing costs, etc. [Means for solving the problem]

[0008] a mixing step of mixing a first plant-based raw material having a silicic acid content of 10% or more with a second plant-based raw material having a silicic acid content of 10% or less; and a carbonization step of heating and carbonizing the plant-based raw material obtained in the mixing step. [Effects of the Invention]

[0009] Due to the above-mentioned features, the present invention makes it possible to simultaneously produce additive materials that can also be used as functional materials for tire reinforcement and water absorption performance, by using additive materials produced from plant raw materials that have a relatively low silicon content and additive materials that have a relatively high silicon content. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a process flow illustrating a manufacturing process for manufacturing an additive material according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] The heat-generating paint of the present invention will be described in detail with reference to the drawings. Note that the embodiments and drawings described below are intended to exemplify some of the embodiments of the present invention, and are not intended to limit the present invention to these configurations, and can be modified as appropriate within the scope of the present invention.

[0012] <Biomass materials> The following describes the plant-based raw material 9 used to produce the additive material 1. The present invention uses food residues or discarded plant-based raw material 9 to produce the final product, the additive material 1. The plant-based raw material 9 uses plants, wood, etc., but if discarded plant-based raw material 9, such as residues from harvesting plants, is used as the raw material for producing graphene, it is possible to obtain the raw material at low cost. [Table 1]

[0013] Table 1 is a list of the ingredients of plant-based raw materials 9. Table 1 shows the proportions of the ingredients that make up the raw materials shown on the left, with the percentages shown on the right. For example, rice straw contains 37.4% carbon (C), 0.53% nitrogen (N), 0.06% phosphorus (P), 0.14% phosphoric acid (PO), 1.75% potassium (K), 2.11% potash (KO), 0.05% calcium (Ca), 0.19% magnesium (Mg), and 0.11% sodium (Na).

[0014] Here, the plant-derived silicon-containing porous plant raw material 9 undergoes no substantial change even when carbonized at low temperatures (300°C or higher and 1000°C or lower), and the arrangement of pores can be maintained by removing the silicon.

[0015] Many plant-derived raw materials 9 have a structure in which cells are regularly arranged along the axis and the cell walls are thickened by the deposition of silicic acid. Furthermore, there are narrow compressed cell rows between the silicified cell rows, and by removing silicon and other substances after carbonization, it is possible to obtain a carbon material with a high specific surface area.

[0016] Plant-based raw materials 9 containing 10% or more of silica include rice husks, bamboo, and horsetail, and those with a high silica content of 13% or more and 35% or less are suitable. If the amount of silica is too high, the amount of carbon obtained will decrease, so plant-based raw materials 9 with a content of about 20% are best.

[0017] Examples of plant-based raw materials9 that are rich in organic matter are shown in Table 1. Among these, plant-based raw materials9 with a silica content of 10% or less include, in addition to rice straw, wheat straw, barley straw, wheat husk, barley husk, cocoa husk, rice bran, buckwheat straw, soybean vines, sweet potato vines, turnip leaves, carrot leaves, corn stalks, sugarcane tops, sake lees, coconut shells, coconut meal, peanut shells, mandarin peel, coffee husks, coffee grounds, shochu lees, beer lees, red cedar sawdust, larch bark, and fallen ginkgo leaves. Plants themselves may also be used instead of residues.

[0018] Bamboo's cellulose is made up of cellulose, hemicellulose, and lignin, and its minerals include iron, magnesium, calcium, manganese, copper, and nickel. Furthermore, when bamboo leaves are burned, silanol groups (Si-OH) are extracted and become SiO4 during the burning process. In particular, silicic acid is found in large amounts in bamboo and bamboo leaves, and the amount of silicic acid varies depending on the time of harvest.

[0019] [Table 2] [Table 3]

[0020] Tables 2 and 3 are tables showing the component composition of rice husks as an example of the plant raw material 9 that is most suitable for the method of producing the additive material 1 of the plant raw materials 9 in Table 1 described above in the present invention. Table 2 shows the percentages of the components that make up the raw material. For example, moisture is 8% to 10%, ash is 10% to 18%, lipids are 0.1% to 0.5%, lignin is 18% to 25%, hemicellulose is 16% to 20%, cellulose is 30% to 35%, and others are 5% to 10%. Thus, the main components that make up additive material 1 are lignin, hemicellulose, and cellulose.

[0021] Table 3 shows the chemical composition of the inorganic matter in plant-based raw material 9 shown in Table 2. Plant-based raw material 9 shown in Table 2 is 80 wt% organic matter such as cellulose, and 20 wt% inorganic matter. The chemical composition of the inorganic matter in Table 3 is 92.14 wt% SiO2, 0.04 wt% Al2O3, 0.48 wt% CaO, 0.03 wt% Fe2O3, 3.2 wt% K2O, 0.16 wt% MgO, 0.18 wt% MnO, and 0.09 wt% Na2O. Plant-based raw material 9 shown in Table 2 contains a large amount of silicon dioxide (SiO2) in its inorganic matter.

[0022] (Example) <Process flow> The steps of the method for producing the additive material 1 will be described with reference to FIG. First, one or more plant materials 9 are selected from a group of first plant materials 11 (for example, bamboo, rice husks, horsetail, etc.) in which the proportion of silicic acid is 10% or more.

[0023] Next, one or more are selected from a group of second plant materials 12 in which the proportion of silica in the plant material 9 is 10% or less (e.g., rice straw, wheat straw, barley straw, wheat husk, barley husk, cocoa husk, rice bran, buckwheat straw, soybean vines, sweet potato vines, turnip leaves, carrot leaves, corn stalks, sugarcane tops, sake lees, coconut shells, coconut meal, peanut shells, mandarin peel, coffee husks, coffee grounds, shochu lees, beer lees, red cedar sawdust, larch bark, and fallen ginkgo leaves).

[0024] Next, these plant-based materials 9 are mixed in a desired ratio (S2). The mixing ratio of the first plant-based material 11 and the second plant-based material 12 is 1:6 to 1:3 so that the weight of silicic acid is relatively small.

[0025] Next, the mixed plant raw material 9 is pulverized by a pulverizer such as a ball mill, a hammer mill, or a stone mill (S3). The particle size is preferably 10 to 150 μm.

[0026] Next, the crushed plant-derived raw material 9 is carbonized in an oxygen-free state at about 500 to 900°C using a continuous or batch carbonization furnace or the like (S4). Methods for creating an oxygen-free state during carbonization include carbonization methods using induction heating or gas heating while flowing nitrogen or argon gas.

[0027] In the carbonization step (S4), instead of using a carbonization furnace, a carbonization treatment method using superheated steam at a temperature of about 300 to 400°C may also be considered.

[0028] The pulverization step (S3) need not be performed, and pulverization may be performed if the particle size needs to be reduced, particularly when the material is made into fine particles.

[0029] The additive material 1 obtained by such a manufacturing method was carbonized by each simple substance, and the specific surface area was measured using the BET adsorption isotherm based on the amount of nitrogen adsorption at liquid nitrogen temperature.

[0030] The first plant-based raw material 11, bamboo, rice husk, etc., has a specific surface area of ​​300 m 2 / g~1200m 2 / g. In particular, by adding a material with a large specific surface area, it is possible to add a function of easily adsorbing water. 2 / g or more is preferred.

[0031] Next, as an additive 1 for reinforcing the strength of a tire, the second plant-based raw material 12, such as wheat or barley husk, cocoa husk, sake lees, shochu lees, beer lees, etc., is 15m 2 / g to 80m 2 / g. Wheat and barley husks, shochu lees, and beer lees were 15m 2 / g to 35m 2 / g. The sake lees were 40m 2 / g to 70m 2 / g. The cocoa shells were 45m 2 / g to 75m 2 / g.

[0032] This small specific surface area makes it ideal for maintaining strength as a reinforcing material for rubber. If it were too large, it would absorb too much chemicals, so it is recommended to limit the specific surface area to 100m. 2 / g or less is preferable.

[0033] The conductive performance of each carbonized additive material 1 was measured by measuring the resistance value of the powder. -2 Ω·cm, sake lees is 2.5×10 -2 Ω·cm, and cocoa shells are 2.5×10 -2 Ω·cm, and rice husk charcoal is 2.3×10 -2 The powder resistivity of wheat and barley husks, cocoa husks, sake lees, shochu lees, and beer lees is approximately 1 to 5 × 10 -2 Ω·cm.

[0034] The powder resistivity of the first plant-derived material 11 and the second plant-derived material 12 after carbonization is 1×10 -3 cm Ω to 3 × 10 3 It is preferable that the resistance is cm·Ω.

[0035] In addition, the purity of wheat and barley husks, shochu lees, and beer lees was 70% to 85% wt of C (carbon), 3% to 15% wt of Si (silicon), and the remaining metal impurities were 0.7% to 1.7% Na, 0.7% to 1.7% Mg, 1.5% to 4% P and K, and 0.35% to 1.0% Ca.

[0036] Furthermore, to further improve the purity of wheat and barley husks, shochu lees, and beer lees, acid treatment with hydrofluoric acid or the like resulted in C (carbon) contents of 86% to 95% by weight, Si (silicon) contents of 3 to 9% by weight, and the remaining metal impurities were K, which was 0.35 to 7% by weight.

[0037] Furthermore, silicon dioxide, a type of silicic acid, is used in tires, but silicon dioxide can also be precipitated by soaking rice husks in citric acid or water, then burning them, or by carbonizing rice husks and then neutralizing the water glass produced with an alkaline agent to precipitate silicon dioxide.

[0038] Additive 1 obtained in the carbonization process and the silicon dioxide produced from rice husks described above are mixed in a ratio of 1:6 to 1:3, and then mixed with rubber and the like to produce tires.

[0039] (Technical features) Below, examples of the technical features of this embodiment are shown in parentheses, but they are not particularly limiting and are merely examples, and the effects that can be expected from these features will also be described.

[0040] <Feature 1> a mixing step (e.g., mainly a mixing step S2) of mixing a first plant-based raw material (e.g., mainly a first plant-based raw material 11) having a silicic acid content of 10% or more with a second plant-based raw material (e.g., mainly a second plant-based raw material 12) having a silicic acid content of 10% or less; The method is characterized by comprising a carbonization process (e.g., mainly carbonization process S4) in which the plant-based raw materials (e.g., mainly the first plant-based raw material 11 and the second plant-based raw material 12) obtained by the mixing process are heated and carbonized.

[0041] By using additive materials made from plant-derived raw materials that have a relatively low silicon content and those that have a relatively high silicon content, it is possible to simultaneously produce additive materials that also serve as functional materials for tire reinforcement and water absorption performance, etc.

[0042] <Feature 2> The first plant-based raw material has a BET specific surface area of ​​100m after carbonization. 2 / g or more, and the BET specific surface area of ​​the second plant raw material after carbonization is 100 m 2 / g or less.

[0043] Due to the above characteristics, by using additive materials produced from plant raw materials with a relatively small specific surface area and a relatively large specific surface area, it is possible to simultaneously produce additive materials that can also be used as functional materials for tire reinforcement and water absorption performance, etc.

[0044] <Feature 3> The blending ratio of the first plant material to the second plant material is characterized by being 1:6 to 1:3. The above characteristics reinforce the rubber and also maintain its hardness.

[0045] <Feature 4> A method for producing additive materials for rubber tires is obtained by mixing the additive obtained in the carbonization process with silicon dioxide produced from rice husks in a ratio of 1:6 to 1:3. The above characteristics reinforce the rubber and also maintain its hardness.

[0046] <Feature 5> The powder resistivity of the first plant raw material and the second plant raw material after carbonization is 1×10 -3 cm Ω to 3 × 10 3cm·Ω. The above features not only improve the strength as a reinforcing material but also the conductive performance of the rubber. [Industrial Applicability]

[0047] Regarding industrial applications of the carbon material of the present invention, it can be used not only as an additive material for tires but also for rubber in general, and can be used as an additive material for rubber used in applications such as packing and elastic absorbent materials. [Explanation of symbols]

[0048] 1···Additive material, 9···Plant-derived raw material, 11···First plant-derived raw material, 12...Second vegetable raw material, S1...Mixing process, S2...Crushing process, S3... Carbonization process.

Claims

1. a mixing step of mixing a first plant-derived raw material having a silicic acid content of 10% or more with a second plant-derived raw material having a silicic acid content of 10% or less; a carbonization step of heating and carbonizing the plant-derived raw material obtained by the mixing step.

2. The first plant raw material has a BET specific surface area of ​​100 m after carbonization. ２ / g or more, The second plant raw material has a BET specific surface area of ​​100 m after carbonization. ２ 2. The method for producing an additive material for rubber tires according to claim 1, wherein the total mass of the additive material is 1000 kJ / g or less.

3. 2. The method for producing an additive material for rubber tires according to claim 1, wherein the mixing ratio of the first plant-derived raw material to the second plant-derived raw material is 1:6 to 1:

3.

4. A method for producing an additive material for rubber tires, which is obtained by mixing the additive obtained in the carbonization process with silicon dioxide produced from rice husks in a ratio of 1:6 to 1:

3.

5. The powder resistivity of the first plant-derived material and the second plant-derived material after carbonization is 1×10 －3 cm Ω to 3 x 10 ３ 2. The method for producing an additive material for rubber tires according to claim 1, characterized in that the modulus of elasticity is cm·Ω.

Images