A SiO2 / C composite material, its preparation method and application

Abstract

This invention belongs to the field of functional filler technology, and discloses a SiO2 / C composite material, its preparation method, and its application. The preparation method of this invention includes the following steps: mixing edible fungus culture medium with porous silica to obtain a silica composite edible fungus culture medium; mixing the silica composite edible fungus culture medium with edible fungi for edible fungus cultivation; after cultivation is complete, removing the edible fungi and retaining the waste culture medium; carbonizing the waste culture medium, followed by crushing and sieving to obtain the SiO2 / C composite material. The SiO2 / C composite material obtained by this invention exhibits a uniform distribution of the SiO2 phase and the biomass carbon phase, and is characterized by its resistance to agglomeration and good dispersibility, making it suitable as a functional filler for rubber. Furthermore, when used as a rubber filler, it possesses excellent low-heat generation performance, overcoming the deficiency of existing two-phase functional fillers in failing to address low-heat generation performance.

Description

Technical Field

[0001] This invention relates to the field of functional filler technology, and in particular to a SiO2 / C composite material, its preparation method, and its application. Background Technology

[0002] Fillers are one of the main raw materials in the rubber industry, imparting various excellent properties to rubber. Among the fillers used, silica and carbon black are the two most important and widely used fillers in rubber materials. Silica-reinforced rubber has advantages such as low heat generation and good insulation, while carbon black-reinforced rubber can significantly increase the wear resistance and tear resistance of rubber materials. Because silica and carbon black each have their own advantages, to obtain better overall performance, silica is often combined with carbon materials, thus producing silicon-carbon dual-phase fillers.

[0003] To prepare silicon-carbon biphase fillers, researchers have conducted extensive studies on composite methods of silicon dioxide and carbon materials. Currently, most silicon-carbon biphase fillers inevitably introduce organic solvents or employ high-temperature methods during preparation, which are environmentally unfriendly and energy-intensive. Regarding the selection of carbon sources, some preparation methods inevitably use petroleum-based raw materials. Furthermore, while the reinforcing effect of fillers in rubber reinforcement has been extensively discussed, the problem of low heat generation performance of fillers is rarely addressed. For example, Chinese invention patent application CN106519301A discloses a method for preparing SiO2 / spiral carbon nanofiber biphase fillers, using various organic solvents such as polyacrylic acid, dicyclohexylcarbodiimide, and dimethylaminopyridine to graft helical nanofibers to obtain SiO2-spiral carbon nanofiber biphase fillers. However, this method adds a large amount of organic solvents during preparation, which is environmentally unfriendly, and only the rubber reinforcement function has been tested; the low heat generation performance of the filler remains unresolved.

[0004] Chinese invention patent application CN112080161A discloses a process for preparing two-phase carbon black. The main steps include: reducing the moisture content of the raw material oil to below 2%; mixing the raw material oil with the combustion gas stream in a reactor at a temperature above 1500°C; and spraying a mixture of silica lattice powder and process water into the carbon black reactor using high-speed jet technology to form two-phase carbon black. However, this method ultimately requires filtration, collection, and separation of the flue gas and exhaust gas, and the preparation process is energy-intensive, requiring the use of petroleum feedstock and consuming a large amount of non-renewable resources.

[0005] Chinese invention patent application CN116948429A discloses a method for preparing and applying a coal gasification slag-based carbon-silicon dual-phase packing. The preparation process involves mixing coal gasification slag with acid and conducting a hydrothermal reaction in a reactor. The resulting product is then mixed with a rubber accelerator to obtain the coal gasification slag-based carbon-silicon dual-phase packing, thus realizing the utilization of coal gasification slag waste. However, the above preparation process involves acidic solvents and does not address the low heat generation performance of the packing.

[0006] Chinese invention patent application CN107200332A discloses a method for preparing nano-silica. The method involves surface modification of cotton stalk fibers using acid, alkali, and fermentation, followed by carbonization of the fibers. Dopamine then undergoes a self-polymerization and cross-linking reaction in the presence of dissolved oxygen in water, forming a dopamine layer on the surface of the carbonized fiber powder to create a modified template. At high temperature, silicic acid is dehydrated to generate silica, which is deposited on the template surface. Finally, the template is removed by calcination. However, this material does not belong to the silicon-carbon dual-phase material category and has not been practically applied in rubber testing. Summary of the Invention

[0007] The purpose of this invention is to provide a SiO2 / C composite material, its preparation method and application, to solve the problem of low heat generation performance that existing dual-phase fillers have not solved, and to realize the green preparation of SiO2 / C dual-phase fillers.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0009] This invention provides a method for preparing SiO2 / C composite materials, comprising the following steps:

[0010] (1) Mix the edible fungus culture medium with porous silica to obtain a silica composite edible fungus culture medium;

[0011] The silica composite edible fungus culture medium is mixed with edible fungi for edible fungus cultivation; after cultivation is completed, the edible fungi are removed, and the waste culture medium is retained.

[0012] (2) Carbonize the waste culture medium described in step (1) to obtain SiO2 / C composite material.

[0013] Preferably, in the preparation method, the porous silica in step (1) includes one or more of silica lattice powder, carbonaceous silage, diatomaceous earth, diatom shale, opal, zeolite and montmorillonite.

[0014] Preferably, in the preparation method, the porous silica in step (1) has a particle size of 500 nm to 100 μm and a specific surface area of ​​60 to 500 m². 2 / g, pore size 2–100 nm, porosity 0.1–5 cm³ 3 / g.

[0015] Preferably, in the preparation method, the mass ratio of the porous silica to the edible fungus culture medium in step (1) is 1:1 to 10.

[0016] Preferably, in the preparation method, the time for the culture to be completed in step (1) is ≥3 months.

[0017] Preferably, in the preparation method, in step (2), the carbonization is carried out under a protective atmosphere, which is at least one of nitrogen or argon; the carbonization temperature is 600-950°C, the time is 10-60 min, and the rate of heating to the required carbonization temperature is 5-15°C / min.

[0018] Preferably, in the preparation method, after carbonization in step (2), the process further includes sequential crushing and sieving.

[0019] Preferably, in the preparation method, the crushing speed is 300-700 rpm and the time is 15-60 min; the particle size D of the sieve is... 50 =500nm~45μm.

[0020] The present invention also provides a SiO2 / C composite material prepared by the aforementioned preparation method.

[0021] The present invention also provides an application of SiO2 / C composite material in rubber, wherein the amount of SiO2 / C composite material is 5 to 80 phr based on 100 phr of rubber; the rubber is natural rubber or synthetic rubber; the synthetic rubber is butadiene rubber or styrene-butadiene rubber.

[0022] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) This invention uses waste edible fungi culture medium as a carbon source and ferments it. Simultaneously, micron-sized silica particles with abundant nanopores are introduced during the preparation of the edible fungi culture medium. The porous structure provides numerous attachment sites for the uniform attachment of fungal microorganisms and offers a favorable temperature and humidity environment for their growth, thus promoting rapid growth. Because the fungal microorganisms exchange organic matter with the surrounding edible fungi culture medium during growth, effectively utilizing components such as starch, polysaccharides, proteins, and esters in the culture medium, the microorganisms and the porous silica structure form a three-dimensional mycelial structure (e.g., microscopic, mesoscopic, and macroscopic). Figure 1As shown in the diagram, this provides numerous attachment sites for biomass carbon dispersion on SiO2, facilitating the formation of molecular-level biomass carbon structures and achieving the organic integration of biomass carbon and porous SiO2. After harvesting mature edible fungi, the discarded silica composite edible fungi culture medium is carbonized, promoting the dehydration and condensation of the biomass carbon structure within the culture medium, removing internal hydrogen and oxygen elements, and creating nanoscale cavities in the original locations, forming a SiO2 / C composite material with excellent structural properties. Therefore, the biomass carbon source in the silica composite edible fungi culture medium, after multiple interactions with the microbial community, forms a natural microporous structure, which, after being combined with SiO2 and fermented again, can become the best source for constructing ideal SiO2 / C composite materials.

[0024] (2) The SiO2 in the preparation method of the present invention comes from minerals and the carbon comes from biomass. Compared with the method of carbon source from petroleum and chemical organic matter synthesis, it is more green and environmentally friendly. It effectively utilizes the waste edible fungus culture body, solves the problems of high energy consumption and environmental unfriendliness in the preparation process of the existing technology, and realizes the green preparation of SiO2 / C composite material.

[0025] (3) By adding different proportions of micron-sized porous silica to the edible fungus culture, the present invention can make up for the lack of biomass silicon in the edible fungus culture and at the same time achieve controllable ratio of carbon to silica in SiO2 / C composite material.

[0026] (4) This invention carbonizes the biomass carbon source with a three-dimensional mycelial structure attached to the porous sites of SiO2, resulting in a SiO2 / C composite material in which the SiO2 phase and the biomass carbon phase are evenly distributed, exhibiting characteristics of being non-agglomerated and having good dispersibility, making it suitable as a functional rubber filler. Simultaneously, the prepared SiO2 / C composite material exhibits excellent low-heat generation performance when used as a rubber filler, overcoming the deficiency of existing biphase functional fillers in failing to address low-heat generation performance. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0028] Figure 1 It consists of porous silica and the three-dimensional hyphal structure of fungi;

[0029] Figure 2 The SEM image for product 1;

[0030] Figure 3 The images show the EDS spectra of products 1 to 3, where a represents product 1, b represents product 2, and c represents product 3.

[0031] Figure 4The curves show the comparison of the low heat generation performance of products 1-3 and N330 carbon black in functionalized rubber. Detailed Implementation

[0032] This invention provides a method for preparing SiO2 / C composite materials, comprising the following steps:

[0033] (1) Mix the edible fungus culture medium with porous silica to obtain a silica composite edible fungus culture medium;

[0034] The silica composite edible fungus culture medium is mixed with edible fungi for edible fungus cultivation; after cultivation is completed, the edible fungi are removed, and the waste culture medium is retained.

[0035] (2) Carbonize the waste culture medium described in step (1) to obtain SiO2 / C composite material.

[0036] In this invention, the edible fungus cultivation medium in step (1) preferably includes a biomass carbon source. The biomass carbon source includes, but is not limited to, one or more of cottonseed hulls, corn cobs, leaf and wood chips, soybean straw powder, wheat straw powder, peanut shells, wheat bran, and rice bran.

[0037] In this invention, the source of the edible fungus culture body described in step (1) is not limited, and commercially available or non-commercially available products well known to those skilled in the art can be used.

[0038] In this invention, the porous silica in step (1) preferably includes one or more of silica lattice powder, carbonaceous silage, diatomaceous earth, diatom shale, opal, zeolite and montmorillonite, more preferably silica lattice powder, diatomaceous earth, diatom shale, opal, zeolite or montmorillonite, and more preferably silica lattice powder.

[0039] In this invention, the preferred grade of the carbon pyrite is TSI-A5008.

[0040] In this invention, the particle size of the porous silica in step (1) is preferably 500 nm to 100 μm, more preferably 500 nm to 50 μm, and even more preferably 500 nm to 10 μm; the specific surface area is preferably 60 to 500 m². 2 / g, further preferably 60-300m 2 / g, more preferably 60-200m 2 / g; pore size preferably 2–100 nm; porosity preferably 0.1–5 cm³. 3 / g, more preferably 0.1–3cm 3 / g, more preferably 0.1-2cm 3 / g.

[0041] In this invention, the mass ratio of the porous silica to the edible fungus culture body in step (1) is preferably 1:1 to 10, more preferably 1:2 to 4, and even more preferably 1:2.

[0042] In this invention, step (1) preferably includes sterilizing the silica composite edible fungus culture before mixing it with edible fungi.

[0043] In this invention, the sterilization conditions are not limited, and any method well known to those skilled in the art can be used. Specifically, in this embodiment of the invention, the sterilization process is performed at 120°C for 1.5 hours or more.

[0044] In this invention, the edible fungi mentioned in step (1) are preferably including, but not limited to, shiitake mushrooms, oyster mushrooms, or wood ear mushrooms. Preferably, in this embodiment of the invention, wood ear mushrooms are used as an example for cultivation.

[0045] In this invention, the time required to complete the cultivation in step (1) is preferably ≥3 months, more preferably ≥3.5 months, and even more preferably 4 months.

[0046] In this invention, step (2) preferably further includes, before carbonization, the waste culture medium from step (1) being naturally dried. The natural drying time is preferably 5 to 24 hours, more preferably 12 to 24 hours, and even more preferably 24 hours.

[0047] In this invention, the equipment used for carbonization in step (2) is preferably a carbonization furnace.

[0048] In this invention, in step (2), the carbonization is preferably carried out under a protective atmosphere; the protective atmosphere is preferably at least one of nitrogen or argon, more preferably nitrogen or argon, and even more preferably nitrogen.

[0049] In this invention, in step (2), the carbonization temperature is preferably 600-950°C, more preferably 700-900°C, and even more preferably 800°C; the time is preferably 10-60 min, more preferably 30-60 min, and even more preferably 60 min; the rate of heating to the desired carbonization temperature is preferably 5-15°C / min, more preferably 5-10°C / min, and even more preferably 5°C / min.

[0050] In this invention, the carbonization process in step (2) preferably further includes sequential crushing and sieving.

[0051] In this invention, the crushing equipment is preferably a planetary ball mill.

[0052] In this invention, the crushing speed in step (2) is preferably 300-700 rpm, more preferably 400-600 rpm, and even more preferably 500 rpm; the time is preferably 15-60 min, more preferably 20-40 min, and even more preferably 30 min.

[0053] In this invention, the screening equipment is preferably a centrifugal classifier.

[0054] In this invention, the particle size D of the sieving in step (2) is... 50 Preferably, the wavelength is 500 nm to 45 μm, more preferably 500 nm to 20 μm, and even more preferably 500 nm to 10 μm.

[0055] The present invention also provides a SiO2 / C composite material prepared by the aforementioned preparation method.

[0056] In this invention, the average particle size of the SiO2 / C composite material is preferably 500 nm to 10 μm, more preferably 800 nm to 5 μm, and even more preferably 1 to 3 μm; the porosity is preferably 0.1 to 2 cm³. 3 / g, more preferably 0.1–0.8cm 3 / g, more preferably 0.15~0.3cm 3 / g; the average pore size is preferably 0.5–100 nm, more preferably 1–40 nm, and even more preferably 5–20 nm; the specific surface area is preferably 30–200 m² / g. 2 / g, more preferably 40-150m 2 / g, more preferably 50-100m 2 / g.

[0057] The present invention also provides an application of SiO2 / C composite material in rubber.

[0058] In the present invention, in the method of application, with the amount of rubber being 100 phr, the amount of the SiO2 / C composite material is preferably 5 to 80 phr, more preferably 15 to 40 phr, and even more preferably 30 phr.

[0059] In this invention, the rubber is preferably natural rubber or synthetic rubber, more preferably natural rubber; the synthetic rubber is preferably butadiene rubber or styrene-butadiene rubber, more preferably butadiene rubber.

[0060] In this invention, other conditions in the application method are not limited, and solutions well known to those skilled in the art can be used.

[0061] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0062] Example 1

[0063] This embodiment provides a method for preparing SiO2 / C composite materials, including the following steps:

[0064] (1) Mix 2kg of Auricularia auricula-judae culture medium (source: Science and Technology Demonstration Park of Dongjingcheng Forestry Bureau, Heilongjiang Province) with 200g of silica powder (D 50 -8μm, model TSI-1, manufactured by Harbin Silicon Ge New Materials Co., Ltd., particle size 500nm~10μm, specific surface area 60~200m² 2 / g, pore size 2–100 nm, porosity 0.1–2 cm³ 3 Mix (g) evenly to obtain a silica composite edible fungus culture medium;

[0065] After sterilizing the silica composite edible fungus culture at 120℃ for 1.5 hours, Auricularia auricula-judae was inoculated into the silica composite edible fungus culture for cultivation. After 3 months of cultivation, the mature Auricularia auricula-judae was removed and the waste culture was retained.

[0066] (2) The waste culture medium described in step (1) is naturally dried for 24 hours, and then placed in a carbonization furnace and carbonized at 800℃ for 60 minutes under nitrogen protection at a heating rate of 5℃ / min. The resulting silicon-carbon composite is ball-milled in a planetary ball mill at a speed of 500 rpm for 30 minutes, and then the ball-milled sample is sieved by a centrifugal classifier to separate the particle size D. 50 Samples with a diameter ≤3μm yielded SiO2 / C composite material, denoted as Product 1.

[0067] Example 2

[0068] This embodiment provides a method for preparing SiO2 / C composite materials, including the following steps:

[0069] (1) Mix 2 kg of Auricularia auricula-judae culture medium (source: Science and Technology Demonstration Park of Dongjingcheng Forestry Bureau, Heilongjiang Province) with 500 g of silica powder (D 50 -8μm, model TSI-1, manufactured by Harbin Silicon Ge New Materials Co., Ltd., particle size 500nm~10μm, specific surface area 60~200m² 2 / g, pore size 2–100 nm, porosity 0.1–2 cm³ 3Mix (g) evenly to obtain a silica composite edible fungus culture medium;

[0070] After sterilizing the silica composite edible fungus culture at 120℃ for 1.5 hours, Auricularia auricula-judae was inoculated into the silica composite edible fungus culture for cultivation. After 3 months of cultivation, the mature Auricularia auricula-judae was removed and the waste culture was retained.

[0071] (2) The waste culture medium described in step (1) is naturally dried for 24 hours, and then placed in a carbonization furnace and carbonized at 800℃ for 60 minutes under nitrogen protection at a heating rate of 5℃ / min. The resulting silicon-carbon composite is ball-milled in a planetary ball mill at a speed of 500 rpm for 30 minutes, and then the ball-milled sample is sieved by a centrifugal classifier to separate the particle size D. 50 Samples with a diameter ≤3μm yielded SiO2 / C composite material, denoted as Product 2.

[0072] Example 3

[0073] This embodiment provides a method for preparing SiO2 / C composite materials, including the following steps:

[0074] (1) Mix 2 kg of Auricularia auricula-judae culture medium (source: Science and Technology Demonstration Park of Dongjingcheng Forestry Bureau, Heilongjiang Province) with 1000 g of silica powder (D 50 -8μm, model TSI-1, manufactured by Harbin Silicon Ge New Materials Co., Ltd., particle size 500nm~10μm, specific surface area 60~200m² 2 / g, pore size 2–100 nm, porosity 0.1–2 cm³ 3 Mix (g) evenly to obtain a silica composite edible fungus culture medium;

[0075] After sterilizing the silica composite edible fungus culture at 120℃ for 1.5 hours, Auricularia auricula-judae was inoculated into the silica composite edible fungus culture for cultivation. After 4 months of cultivation, the mature Auricularia auricula-judae was removed and the waste culture was retained.

[0076] (2) The waste culture medium described in step (1) is naturally dried for 24 hours, and then placed in a carbonization furnace and carbonized at 800℃ for 60 minutes under nitrogen protection at a heating rate of 5℃ / min. The resulting silicon-carbon composite is ball-milled in a planetary ball mill at a speed of 500 rpm for 30 minutes, and then the ball-milled sample is sieved by a centrifugal classifier to separate the particle size D. 50 Samples with a diameter ≤3μm yielded SiO2 / C composite material, denoted as Product 3.

[0077] The particle size, porosity, average pore size and specific surface area of ​​products 1 to 3 were tested, and the results are shown in Table 1.

[0078] Table 1. Characteristic physical properties of products 1-3

[0079] Characteristic properties Product 1 Product 2 Product 3 Average particle size (μm) 2.1 2.4 2.2 <![CDATA[Porosity (cm 3 / g)]]> 0.206 0.221 0.238 Average pore size (nm) 9.813 9.478 9.326 <![CDATA[Specific surface area (m 2 / g)]]> 78.04 81.64 83.35

[0080] Product 1 was subjected to SEM testing, and the results are as follows: Figure 2 As shown. By Figure 2 It can be seen that the particle size of the SiO2 / C composite material is generally distributed in the range of 0.5 to 3 μm.

[0081] Products 1–3 were characterized by EDS energy dispersive spectroscopy, and the results are as follows: Figure 3 As shown, Figure 3 In this context, 'a' represents the characterization result of product 1. Figure 3 In the diagram, b represents the characterization result of product 2. Figure 3 In the figure, 'c' represents the characterization result of product 3. (From...) Figure 3 It can be seen that by comparing the atomic percentages of carbon and silicon, the proportion of carbon gradually decreases, indicating that the solution of the present invention achieves the control of the ratio of carbon and silicon dioxide in SiO2 / C composite materials.

[0082] Application Example 1

[0083] Parts 5, 10, 15, 20, 25 and 30 of product 1 were respectively mixed with a mixture of natural rubber, zinc oxide, stearic acid, silane coupling agent Si-69, antioxidant RD, accelerator DM and sulfur, as shown in Table 2, to obtain functionalized rubber 1.

[0084] Application Example 2

[0085] Parts 5, 10, 15, 20, 25 and 30 of product 2 were respectively mixed with a mixture of natural rubber, zinc oxide, stearic acid, silane coupling agent Si-69, antioxidant RD, accelerator DM and sulfur, as shown in Table 2, to obtain functionalized rubber 2.

[0086] Application Example 3

[0087] Parts 5, 10, 15, 20, 25 and 30 of product 3 were respectively mixed with a mixture of natural rubber, zinc oxide, stearic acid, silane coupling agent Si-69, antioxidant RD, accelerator DM and sulfur, as shown in Table 2, to obtain functionalized rubber 3.

[0088] Comparative Application Example 1

[0089] 5, 10, 15, 20, 25 and 30 parts of carbon black N330 were respectively mixed with a mixture of natural rubber, zinc oxide, stearic acid, antioxidant RD, accelerator DM and sulfur, as shown in Table 2, to obtain functionalized rubber 4.

[0090] Table 2. Application Examples 1-3, Comparative Application Example 1 (Unit: portions)

[0091]

[0092]

[0093] Figure 4 This is a comparison curve of the low heat generation properties of products 1-3 and N330 carbon black in functionalized rubber. Figure 4 It can be seen that, compared with carbon black, the functionalized rubber prepared from SiO2 / C composite material has significantly improved low heat generation performance.

[0094] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a SiO2 / C composite material, characterized in that, Includes the following steps: (1) Mix the edible fungus culture medium with porous silica to obtain a silica composite edible fungus culture medium; The silica composite edible fungus culture medium is mixed with edible fungi for edible fungus cultivation; after cultivation is completed, the edible fungi are removed and the waste culture medium is retained. (2) Carbonize the waste culture medium described in step (1) to obtain SiO2 / C composite material; In step (1), the mass ratio of the porous silica to the edible fungus culture medium is 1:1~10.

2. The preparation method according to claim 1, characterized in that, The porous silica in step (1) includes one or more of silica lattice powder, carbon silicide, diatomaceous earth, diatom shale and opal.

3. The preparation method according to claim 1 or 2, characterized in that, The porous silica in step (1) has a particle size of 500 nm to 100 μm and a specific surface area of ​​60 to 500 m². 2 / g, pore size 2~100nm, porosity 0.1~5cm 3 / g.

4. The preparation method according to claim 1, characterized in that, The cultivation process described in step (1) takes ≥ 3 months to complete.

5. The preparation method according to claim 1 or 4, characterized in that, In step (2), the carbonization is carried out under a protective atmosphere, which is at least one of nitrogen or argon; the carbonization temperature is 600~950℃, the time is 10~60min, and the rate of heating to the required carbonization temperature is 5~15℃ / min.

6. The preparation method according to claim 1, 2 or 4, characterized in that, Step (2) after carbonization also includes: sequential crushing and screening.

7. The preparation method according to claim 6, characterized in that, The crushing speed is 300~700 rpm, and the time is 15~60 min; the particle size D of the sieve is... 50 =500nm~45μm.

8. A SiO2 / C composite material prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the SiO2 / C composite material according to claim 8 in rubber, characterized in that, Based on a rubber content of 100 phr, the SiO2 / C composite material is used in an amount of 5-80 phr; the rubber is natural rubber or synthetic rubber; the synthetic rubber is butadiene rubber or styrene-butadiene rubber.

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