Method for analyzing wax or rubber composition, and rubber composition

Abstract

To provide a method for analyzing a wax or rubber composition that allows components such as structural isomers to be easily visualized, and to provide a rubber composition excellent in ozone resistance.SOLUTION: The method for analyzing a wax or rubber composition is a method using chromatography for analyzing a wax or rubber composition, the method being characterized in that an RI-plot method is used for analysis of the chromatography.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for analyzing a wax or a rubber composition, and to a rubber composition. [Background technology]

[0002] In order to improve the ozone resistance of rubber compositions, various methods are being considered, including optimizing and developing waxes, modifying the polymer skeleton, and adjusting the hardness and modulus of elasticity to adjust the amount of strain during tire use. Of the above methods, modifying the polymer skeleton and adjusting the hardness and modulus of elasticity are difficult to optimize because they significantly change tire properties other than ozone resistance, such as fuel economy and ride comfort. On the other hand, optimizing and developing waxes is considered a desirable method because it contributes little to changes in tire performance other than ozone resistance and can be applied to a variety of rubber compounds, and various studies are being conducted on this method (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-116847 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to solve the above problems and provide a method for analyzing wax or rubber compositions that can easily visualize components such as structural isomers, and a rubber composition that has excellent ozone resistance. [Means for solving the problem]

[0005] The present invention provides a method for analyzing a wax or rubber composition using chromatography, comprising: The present invention relates to a method for analyzing a wax or rubber composition, characterized in that the RI-plot method is used for the chromatographic analysis. [Effects of the Invention]

[0006] According to the present invention, there is provided a method for analyzing a wax or rubber composition using chromatography, characterized in that the RI-plot method is used for the chromatographic analysis. This provides a method for analyzing a wax or rubber composition that can easily visualize components such as structural isomers, and a rubber composition that has excellent ozone resistance. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an example of a diagram schematically illustrating the RI-plot method. [Figure 2] This is an example of a two-dimensional plot of a chromatogram obtained by gas chromatography (GC) of a specific wax, with the chromatogram elution time (RI: retention index) on the x-axis and the integer part of the RI and the difference between the RI (ΔRI) on the y-axis. [Figure 3] This is an example of a two-dimensional plot of chromatograms obtained by gas chromatography (GC) of various waxes, with the chromatogram elution time (RI: retention index) on the x-axis and the difference between the integer part of the RI and the RI (ΔRI) on the y-axis. DETAILED DESCRIPTION OF THE INVENTION

[0008] <Method for analyzing wax or rubber composition> The method for analyzing the wax and the method for analyzing the rubber composition containing the wax are analytical methods using chromatography, characterized in that the RI-plot method is used for the chromatographic analysis.

[0009] Analysis using gas chromatography (GC), a commonly used method for evaluating wax characteristics, is largely manual, and there has been little effort to optimize wax by combining statistical methods such as experimental design and multivariate analysis. The Kendrick Mass Defect (KMD) method is widely used to obtain structural information on polymeric materials, but the KMD method cannot be applied to components with the same mass, such as structural isomers (for example, normal- and iso-structural isomers of hydrocarbon (olefin-based) materials). On the other hand, in the above analytical method, components such as structural isomers with branched structures and compounds with the same carbon number are regularly detected on the chromatogram. Therefore, the RI-plot method was investigated, and by using the RI-plot method as a method for chromatographic analysis of wax alone or rubber compositions containing wax, it becomes possible to easily visualize structural isomers of hydrocarbons contained in wax and compounds with the same carbon number.

[0010] Furthermore, by using the RI-plot method as a chromatographic analysis method, structural isomers of hydrocarbons can be easily visualized, making it possible to analyze and identify each hydrocarbon component in wax, including structural isomers of hydrocarbons.

[0011] The method for analyzing the wax or rubber composition is an analytical method using chromatography. The chromatography is not particularly limited, and examples thereof include gas chromatography (GC), liquid chromatography (LC), supercritical fluid chromatography, thin layer chromatography, etc. The detector for the chromatography is not particularly limited, and examples that can be used include flame ionization (FID) and mass spectrometry (MS).

[0012] In the above analytical method, the RI-plot method is used for analyzing the above chromatography. The RI-plot method is a two-dimensional plotting technique in which the elution time of a chromatogram (RI: retention index) is plotted on the x-axis and the difference between the integer part of RI and the RI (ΔRI) is plotted on the y-axis.

[0013] FIG. 1 is an example of a diagram that schematically illustrates the RI-plot method. Figure 1(a) shows an example of a chromatogram obtained by gas chromatography (GC) of a single wax. Each resulting RT is converted to an RI, which is carried out as follows: First, measurements are performed using a retention index standard reagent (e.g., GC-MS standard reagents, manufactured by GL Sciences, etc.) to obtain the retention time (RT) and carbon number (RI) of normal alkanes on the chromatogram. From these, an RT vs. RI correlation equation is created (this can be done, for example, within analysis software), and then the RT for each measured wax is converted to RI. RI and ΔRI are then calculated and plotted in two dimensions.

[0014] For example, Figure 1(a) shows a compound with the molecular formula C 33 H 68 Not only did we observe a large peak (RI: 33.00, integer part) attributed to normal alkane with a linear structure, but also its structural isomer, molecular formula C 33 H 68 Two peaks (RI: 32.80, ΔRI: 0.20) (RI: 32.70, ΔRI: 0.30) attributed to isoalkane with a branched structure, and a peak of molecular formula C 33 H 66 It can be seen that one peak assigned to an alkane having a cyclic structure (RI: 32.60, ΔRI: 0.40) was detected.

[0015] As shown in Figure 1(a), the above analytical method can use the RI-plot method to detect, for example, normal alkanes with a linear structure contained in wax, isoalkanes with a branched structure which are structural isomers of the normal alkanes with a linear structure, and alkanes with a cyclic structure which are compounds having the same number of carbon atoms as the normal alkanes with a linear structure.

[0016] Figure 1(b) shows that by applying the RI-plot method, which plots the chromatogram obtained by gas chromatography (GC) of the wax alone in Figure 1(a) two-dimensionally, with the elution time of the chromatogram (RI: retention index) on the x-axis and the difference between the integer part of the RI and the RI (ΔRI) on the y-axis, a scatter plot can be obtained in which the normal alkanes with a linear structure contained in the wax, the isoalkanes with a branched structure that are structural isomers of the normal alkanes with a linear structure, and compounds with the same carbon number as the normal alkanes with a linear structure, as well as their amounts, are schematically plotted.

[0017] As shown in Figure 1(b), the RI-plot method makes it easy to visualize the normal alkanes (n-alkanes) with a straight-chain structure contained in wax, their structural isomers, the isoalkanes with a branched structure, and the alkanes with a cyclic structure, as well as their amounts.

[0018] Specifically, as shown in Figure 1(b), by applying the RI-plot method to the obtained wax chromatogram, the C contained in the wax was identified. 32 H 66 and C 32 H 64 , C 33 H 68 and C 33 H 66 , C 34 H 70 and C 34 H 68 , C 35 H 72 and C 35 H 70 For each component, the molecular formula C 32 H 66 , C 33 H 68 , C 34 H 70 , C 35 H 72 Normal alkanes (a series of n-alkanes with a decimal term of 0) with a linear structure of C 32 H 66 , C 33 H 68 , C34 H 70 , C 35 H 72 isoalkane with a branched structure, and molecular formula C 32 H 64 , C 33 H 66 , C 34 H 68 , C 35 H 70 The components of alkanes with cyclic structures (series with non-zero decimal terms: isoalkanes with branched structures that are structural isomers, series of alkanes with cyclic structures with the same number of carbon atoms) and the content of each component can be easily visualized.

[0019] In the scatter diagram of Figure 1(b), the difference in the size of the plots (points) shows the content of the hydrocarbons. 33 H 68 and C 33 H 66 Regarding wax, the molecular formula C is shown in the large plot. 33 H 68 The content of normal alkanes with a linear structure of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 33 H 68 Isoalkanes with branched structures and the same carbon number with the molecular formula C 33 H 66 The figure shows that the content of alkanes with cyclic structures is low.

[0020] While Figure 1 shows an example of using the RI-plot method for chromatographic analysis of a wax alone, the RI-plot method can also be used to analyze rubber compositions containing wax. In the case of a wax alone, for example, a sample obtained by dissolving the wax alone in an organic solvent and heating it to its melting point is subjected to chromatography to obtain a chromatogram like that shown in Figure 1(a). By applying the RI-plot method to the chromatogram, a scatter plot like that shown in Figure 1(b) is obtained. In the case of a rubber composition containing wax, for example, a sample obtained by extracting the wax from the rubber composition with an organic solvent or a sample obtained by scraping the surface of the rubber composition is subjected to chromatography and the RI-plot method in the same manner as for a wax alone, and a chromatogram and scatter plot like those shown in Figures 1(a) and 1(b) are obtained.

[0021] Figure 2 shows an example of a two-dimensional plot of a chromatogram obtained by gas chromatography (GC) of a specific wax. The x-axis represents the chromatogram elution time (RI: retention index) and the y-axis represents the difference between the integer part of the RI and the RI (ΔRI). Figure 2(b) shows that this wax has five signals in the ΔRI region: (1) components with ΔRI values ​​of -0.45 or more and less than -0.35, (2) components with ΔRI values ​​of -0.35 or more and less than -0.20, (3) components with ΔRI values ​​of -0.20 or more and less than -0.10, (4) components with ΔRI values ​​of +0.20 or more and less than +0.30, and (5) components with ΔRI values ​​of +0.30 or more and less than +0.40.

[0022] Figure 3 shows an example of a two-dimensional plot of chromatograms obtained by gas chromatography (GC) of various waxes, with the chromatogram elution time (RI: retention index) on the x-axis and the difference between the integer part of the RI and the RI (ΔRI) on the y-axis.

[0023] The organic solvent is not particularly limited as long as it can extract wax, and examples thereof include cyclohexane, tetrahydrofuran (THF), chloroform, and toluene.

[0024] As described above, the above analytical method is a method that uses the RI-plot method for chromatographic analysis, and by using this method, for example, for a sample of wax alone or a sample of a rubber composition containing wax, it is possible to detect and identify normal alkanes with a linear structure contained in the wax, isoalkanes with a branched structure that are structural isomers of the normal alkanes with a linear structure, and alkanes with a cyclic structure that are compounds having the same number of carbon atoms as the normal alkanes with a linear structure, and further to easily visualize the structure and content of each of these components.

[0025] <Rubber composition> The rubber composition (hereinafter also referred to as "first rubber composition") contains a rubber component and a wax, and the wax has a signal in a predetermined ΔRI region when the chromatographic analysis method of the wax is performed using the RI-plot method, which plots the elution time (RI) of a chromatogram on the x-axis and the difference (ΔRI) between the integer part of the RI and the RI on the y-axis, and creates a two-dimensional plot. The rubber composition (hereinafter also referred to as "second rubber composition") includes a rubber component and a wax, wherein the wax includes a normal alkane having a linear structure, and an isoalkane having a branched structure which is a structural isomer of the normal alkane having a linear structure and / or an alkane having a cyclic structure which is a compound having the same number of carbon atoms as the normal alkane having a linear structure, and the content of the normal alkane having a linear structure in 100% by mass of the wax is less than 95% by mass. Furthermore, the rubber composition (hereinafter also referred to as "third rubber composition") contains a rubber component and a wax, and when the chromatographic analysis of the wax is performed using an RI-plot method in which the elution time (RI) of a chromatogram is plotted two-dimensionally on the x-axis and the difference between the integer part of the RI and the RI (ΔRI) is plotted on the y-axis, the wax contains isoalkanes having a branched structure and / or alkanes having a cyclic structure having five signals in the ΔRI ranges of (1) to (5) below, and the isoalkanes having a branched structure and / or alkanes having a cyclic structure have a carbon number distribution within a certain range. (1) Components with a ΔRI value of -0.45 or more and less than -0.35 (2) Components with a ΔRI value of -0.35 or more and less than -0.20 (3) Components with a ΔRI value of -0.20 or more and -0.10 or less (4) Ingredients with a ΔRI value of +0.20 or more and less than +0.30 (5) Components with a ΔRI value of +0.30 or more and +0.40 or less

[0026] As described above, by using the RI-plot method as a chromatographic analysis method, it is possible to easily visualize the normal alkanes having a linear structure, the isoalkanes having a branched structure, and the alkanes having a cyclic structure contained in the wax, and to analyze and identify the structure and content of each hydrocarbon component in the wax. Therefore, for example, by examining the relationship between the amount of each hydrocarbon component in the wax contained in a rubber composition and the ozone resistance of the rubber composition, it is possible to identify hydrocarbon components in the wax that contribute greatly to improving ozone resistance, and by using these components, it is possible to provide a rubber composition with excellent ozone resistance.

[0027] The materials contained in the first rubber composition, the second rubber composition, and the third rubber composition will be described below.

[0028] The first rubber composition, the second rubber composition, and the third rubber composition each contain a rubber component. In this specification, the rubber component is a component that contributes to crosslinking and is generally a polymer with a weight-average molecular weight (Mw) of 10,000 or more that is not extracted with acetone. The rubber component is in a solid state at 25°C.

[0029] The weight average molecular weight of the rubber component is preferably 50,000 or more, more preferably 150,000 or more, even more preferably 200,000 or more, and particularly preferably 270,000 or more, and is preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less. Within the above ranges, the effect tends to be more favorably obtained.

[0030] In this specification, the weight average molecular weight (Mw) can be determined in terms of standard polystyrene based on measurements obtained using a gel permeation chromatograph (GPC) (GPC-8000 series, manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M, manufactured by Tosoh Corporation).

[0031] The rubber components that can be used in the first, second and third rubber compositions may be unmodified rubber or modified rubber. Examples of modified rubbers include rubbers having functional groups that interact with fillers such as silica. Examples include terminal-modified rubbers (terminal-modified rubbers having the functional groups at the terminals) in which at least one terminal of the rubber has been modified with a compound (modifier) ​​having the functional group, main-chain-modified rubbers having the functional groups in the main chain, main-chain-terminal-modified rubbers having the functional groups in the main chain and at the terminals (for example, main-chain-terminal-modified rubbers having the functional groups in the main chain and at least one terminal modified with the modifier), and terminal-modified rubbers modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and having hydroxyl groups or epoxy groups introduced therein.

[0032] Examples of the functional group include an amino group, an amide group, a silyl group, an alkoxysilyl group, an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group, a disulfide group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imido group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group, a hydroxyl group, an oxy group, and an epoxy group. These functional groups may have a substituent. Among these, an amino group (preferably an amino group in which a hydrogen atom of the amino group is substituted with an alkyl group having 1 to 6 carbon atoms), an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms), and an alkoxysilyl group (preferably an alkoxysilyl group having 1 to 6 carbon atoms) are preferred.

[0033] In the first, second, and third rubber compositions, examples of rubber components that can be used include diene rubbers. Examples of diene rubbers include isoprene rubbers, butadiene rubbers (BR), styrene butadiene rubbers (SBR), styrene isoprene butadiene rubbers (SIBR), ethylene propylene diene rubbers (EPDM), chloroprene rubbers (CR), and acrylonitrile butadiene rubbers (NBR). Examples of rubber components include butyl rubbers and fluororubbers. These may be used alone or in combination of two or more. These rubber components may be modified or hydrogenated, and extended rubbers extended with oil, resin, liquid rubber components, or the like may also be used.

[0034] The raw materials (monomers) for synthetic rubbers such as IR, SBR, and BR may be derived from underground resources such as petroleum and natural gas, or may be recycled from rubber products such as tires or non-rubber products such as polystyrene. Monomers obtained by recycling (recycled monomers) are not particularly limited, and examples include recycled isoprene, recycled butadiene, and recycled aromatic vinyls. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyls include, but are not limited to, styrene. Among these, it is preferable to use recycled isoprene (recycled isoprene), recycled butadiene (recycled butadiene), and / or recycled styrene (recycled styrene) as raw materials.

[0035] The method for producing the recycled monomer is not particularly limited, and examples thereof include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. The method for producing recycled naphtha is also not particularly limited, and examples thereof include decomposing rubber products such as tires under high temperature and pressure, decomposing with microwaves, or mechanically crushing and then extracting.

[0036] Furthermore, the raw materials (monomers) of synthetic rubbers such as IR, SBR, and BR may be derived from biomass. In this specification, biomass refers to materials derived from natural resources such as plants. Examples of biomass include, but are not limited to, agricultural, forestry, and fishery products, sugar, wood chips, plant residues after useful components have been extracted, plant-derived ethanol, and biomass naphtha.

[0037] Monomers derived from biomass (biomass monomers) are not particularly limited and include biomass-derived butadiene and biomass-derived aromatic vinyl. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyls include, but are not limited to, styrene. The method for producing biomass monomers is not particularly limited and includes, for example, biological and / or chemical and / or physical conversion of animals and plants. A representative example of biological conversion is fermentation by microorganisms, and examples of chemical and / or physical conversion include catalytic conversion, high heat conversion, high pressure conversion, electromagnetic wave conversion, critical fluid conversion, and combinations thereof.

[0038] The polymer synthesized from a biomass monomer component (biomass polymer) is not particularly limited, and examples thereof include polybutadiene rubber synthesized from biomass-derived butadiene, and aromatic vinyl / butadiene copolymer synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl. Examples of the aromatic vinyl / butadiene copolymer include styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0039] Whether the raw material for a polymer is derived from biomass can be determined by the pMC (percent modern carbon) measured in accordance with ASTM D6866-10.

[0040] pMC is the modern standard reference carbon 14 of sample against C concentration14 This is the ratio of C concentrations and is a value used as an index of the biomass ratio of a compound. The significance of this value is explained below.

[0041] 1 mole of carbon atoms (6.02 × 10 23 ) contains approximately 6.02 × 10 atoms, which is about one trillionth of the number of ordinary carbon atoms. 11 pieces 14 C exists. 14 C is called a radioactive isotope, and its half-life is 5,730 years, and it decreases regularly. It takes 226,000 years for all of it to decay. Therefore, in fossil fuels such as coal, oil, and natural gas, which are thought to have been absorbed and fixed by plants and other organisms more than 226,000 years ago, C was also included in these when it was first fixed. 14 All C elements have decayed. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas contain 14 Therefore, chemicals produced from these fossil fuels do not contain any C element. 14 It does not contain any C element.

[0042] on the other hand, 14 C is produced continuously by nuclear reactions in the atmosphere caused by cosmic rays, and this balances with the decrease due to radioactive decay. In the Earth's atmospheric environment, 14 Therefore, the amount of carbon derived from biomass resources currently circulating in the environment is constant. 14 As mentioned above, the C concentration is approximately 1 × 10 -12 The value is approximately mol %. Therefore, the biomass ratio of a certain compound can be calculated by using the difference between these values.

[0043] this 14 C is typically measured using accelerator mass spectrometry based on a tandem accelerator. 13 C concentration ( 13 C / 12 C). 14 C concentration ( 14 C / 12 C) is measured.14 The modern standard reference for the C concentration is the carbon circulating in nature as of 1950. 14 The specific standard substance used is the oxalic acid standard provided by NIST (National Institute of Standards and Technology). The specific activity of carbon in this oxalic acid (per gram of carbon) is 14 The radioactivity of C is separated into carbon isotopes, 13 The standard value is the value corrected for decay from 1950 to the measurement date. 14 This is used as the C concentration value (100%). The ratio of this value to the value of the actually measured sample is the pMC value.

[0044] Therefore, if rubber is made from 100% biomass-derived materials, although there are regional differences, under normal circumstances, it will usually not reach 100, and will show a value of approximately 110 pMC. On the other hand, for chemical substances derived from petroleum and other fossil fuels, 14 When the carbon concentration is measured, it will show a value of about 0 pMC (for example, 0.3 pMC), which corresponds to the biomass ratio of 0% mentioned above.

[0045] From the above, it is preferable in terms of environmental protection to use a material such as rubber having a high pMC value, that is, a material such as rubber having a high biomass ratio, in a rubber composition.

[0046] In particular, the first rubber composition, the second rubber composition and the third rubber composition preferably contain at least one selected from the group consisting of isoprene-based rubber, BR and SBR.

[0047] Examples of isoprene-based rubbers include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. NRs such as SIR20, RSS#3, and TSR20 are commonly used in the rubber industry. IRs are not particularly limited, and examples of IRs such as IR2200 are commonly used in the rubber industry. Modified NRs include deproteinized natural rubber (DPNR) and high-purity natural rubber. Modified NRs include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Modified IRs include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used alone or in combination of two or more.

[0048] The BR is not particularly limited, and examples thereof include high-cis BR with a high cis content, BR containing syndiotactic polybutadiene crystals, and BR synthesized using a rare earth catalyst (rare earth BR). These may be used alone or in combination of two or more. Of these, the BR preferably contains high-cis BR with a cis content of 90% by mass or more. The cis content is more preferably 95% by mass or more. The cis content can be measured by infrared absorption spectroscopy.

[0049] The cis content of BR means the cis content of the BR when there is one type of BR, and means the average cis content when there are multiple types of BR. The average cis content of BR can be calculated by {Σ(content of each BR × cis content of each BR)} / total content of all BRs. For example, when 100% by mass of the rubber component contains 20% by mass of BR with a cis content of 90% by mass and 10% by mass of BR with a cis content of 40% by mass, the average cis content of BR is 73.3% by mass (=(20×90+10×40) / (20+10)).

[0050] Both unmodified and modified BR can be used. Modified BR includes modified BR with the same functional groups as modified rubber. Hydrogenated butadiene polymer (hydrogenated BR) can also be used.

[0051] The SBR is not particularly limited, and examples thereof include emulsion-polymerized styrene-butadiene rubber (E-SBR), solution-polymerized styrene-butadiene rubber (S-SBR), etc. These may be used alone or in combination of two or more.

[0052] The styrene content of the SBR is preferably 5% by mass or more, more preferably 20% by mass or more, and even more preferably 23.5% by mass or more. The styrene content is preferably 60% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less. Within the above range, the effect tends to be more favorable. In this specification, the styrene content is 1 It can be measured by H-NMR measurement.

[0053] The styrene content of SBR means the styrene content of the SBR when there is one type of SBR, and means the average styrene content when there are multiple types of SBR. The average styrene amount of SBR can be calculated by {Σ(content of each SBR × styrene amount of each SBR)} / total content of all SBRs. For example, when 100% by mass of the rubber component contains 85% by mass of SBR with a styrene amount of 40% by mass and 5% by mass of SBR with a styrene amount of 25% by mass, the average styrene amount of the SBR is 39.2% by mass (=(85×40+5×25) / (85+5)).

[0054] The vinyl bond content of SBR is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more. When the vinyl bond content is within the above range, that is, preferably 70% by mass or less, more preferably 65% ​​by mass or less, and even more preferably 60% by mass or less, better effects tend to be obtained. In this specification, the vinyl bond amount (amount of 1,2-bonded butadiene units) can be measured by infrared absorption spectroscopy.

[0055] The vinyl content of SBR (amount of 1,2-bonded butadiene units) is the proportion of vinyl bonds (unit: mass%) when the total mass of the butadiene parts in the SBR is taken as 100, and is calculated as vinyl content [mass%] + cis content [mass%] + trans content [mass%] = 100 [mass%]. When there is one type of SBR, it means the vinyl content of that SBR, and when there are multiple types, it means the average vinyl content. The average vinyl content of SBR can be calculated by Σ{content of each SBR × (100 [mass%] - styrene content of each SBR [mass%]) × vinyl content of each SBR [mass%]} / Σ{content of each SBR × (100 [mass%] - styrene content of each SBR [mass%])}. For example, in 100 parts by mass of the rubber component, 75 parts by mass of SBR with a styrene content of 40% by mass and a vinyl content of 30% by mass, 25 parts by mass of styrene and 10 parts by mass of vinyl are used. In the case where 15 parts by mass of SBR with a vinyl content of 20% by mass is used and the remaining 10 parts by mass are other than SBR, the average vinyl content of the SBR is 28% by mass (= {75 × (100 [% by mass] - 40 [% by mass]) × 30 [% by mass] + 15 × (100 [% by mass] - 25 [% by mass]) × 20 [% by mass])} / {75 × (100 [% by mass] - 40 [% by mass]) + 15 × (100 [% by mass] - 25 [% by mass])}.

[0056] Both unmodified and modified SBR can be used. Modified SBR includes modified SBR with the same functional groups as modified rubber. Hydrogenated styrene-butadiene copolymer (hydrogenated SBR) can also be used as SBR.

[0057] When the first rubber composition, the second rubber composition, and the third rubber composition contain an isoprene-based rubber, the content of the isoprene-based rubber in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 30% by mass or more, and even more preferably 50% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. When the content is within the above range, better effects tend to be obtained.

[0058] When the first rubber composition, the second rubber composition, and the third rubber composition contain BR, the content of BR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 30% by mass or more, and even more preferably 50% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. When the content is within the above ranges, better effects tend to be obtained.

[0059] When the first rubber composition, the second rubber composition, and the third rubber composition contain SBR, the content of SBR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 30% by mass or more, and even more preferably 50% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. When the content is within the above ranges, better effects tend to be obtained.

[0060] The first rubber composition, the second rubber composition, and the third rubber composition each contain a wax. Here, the wax contained in the first rubber composition has a signal in a predetermined ΔRI region when the chromatographic analysis of the wax is performed using the RI-plot method, which plots the chromatogram elution time (RI) on the x-axis and the difference between the integer part of RI and the RI (ΔRI) on the y-axis, and creates a two-dimensional plot. The wax contained in the second rubber composition contains a normal alkane having a linear structure, and an isoalkane having a branched structure which is a structural isomer of the normal alkane having a linear structure and / or an alkane having a cyclic structure which is a compound having the same number of carbon atoms as the normal alkane having a linear structure, and the content of the normal alkane having a linear structure in 100% by mass of the wax is less than 95% by mass. When the chromatographic analysis of the wax is performed using the RI-plot method, which plots the elution time (RI) of a chromatogram on the x-axis and the difference (ΔRI) between the integer part of RI and the RI on the y-axis, the wax contained in the third rubber composition contains isoalkanes having a branched structure and / or alkanes having a cyclic structure, each of which has five signals in the ΔRI ranges (1) to (5) below, and the isoalkanes having a branched structure and / or alkanes having a cyclic structure have a carbon number distribution within a certain range. (1) Components with a ΔRI value of -0.45 or more and less than -0.35 (2) Components with a ΔRI value of -0.35 or more and less than -0.20 (3) Components with a ΔRI value of -0.20 or more and -0.10 or less (4) Ingredients with a ΔRI value of +0.20 or more and less than +0.30 (5) Components with a ΔRI value of +0.30 or more and +0.40 or less

[0061] It is desirable that the wax contained in the first rubber composition, the wax contained in the second rubber composition, and the wax contained in the third rubber composition all have the properties, content, etc. described below.

[0062] Examples of the wax contained in the first rubber composition and the second rubber composition include those having a signal in the ΔRI region (those having a detection peak in the ΔRI region) as shown in FIG. 1(a) (for example, those having the molecular formula C 33 H 68 Not only did we observe a large peak (RI: 33.00, integer part) attributed to normal alkane with a linear structure, but also its structural isomer, molecular formula C 33 H 68 Two peaks (RI: 32.80, ΔRI: -0.20) (RI: 32.70, ΔRI: -0.30) attributed to isoalkane with a branched structure, and a peak of molecular formula C 33 H 66One peak is detected that is attributed to an alkane with a cyclic structure (RI: 32.60, ΔRI: -0.40) and another peak is detected that is attributed to a wax (e.g., wax).

[0063] Furthermore, examples of the wax contained in the third rubber composition include those having five signals in the ΔRI region as shown in Figures 2(a) and (b) above ((1) components having a ΔRI value of -0.45 or more and less than -0.35, (2) components having a ΔRI value of -0.35 or more and less than -0.20, (3) components having a ΔRI value of -0.20 or more and less than -0.10, (4) components having a ΔRI value of +0.20 or more and less than +0.30, and (5) components having a ΔRI value of +0.30 or more and +0.40 or less).

[0064] From the viewpoint of ozone resistance, the wax having a signal in the above-mentioned predetermined ΔRI range is preferably one having a signal (having a detection peak) in a ΔRI range of -0.80 to -0.06 or +0.06 to +0.80. The range is preferably -0.70 to -0.07 or +0.07 to +0.70, more preferably -0.60 to -0.08 or +0.08 to +0.60, and even more preferably -0.50 to -0.09 or +0.09 to +0.50. The signals in the ΔRI range of −0.05 to +0.05 are attributed to normal alkanes with a straight-chain structure.

[0065] Furthermore, from the viewpoint of ozone resistance, it is desirable that the waxes contained in the first rubber composition, the second rubber composition, and the third rubber composition contain normal alkanes having a straight-chain structure contained in the wax, and isoalkanes having a branched structure which are structural isomers of the normal alkanes having a straight-chain structure and / or alkanes having a cyclic structure which are compounds having the same number of carbon atoms as the normal alkanes having a straight-chain structure, when detected by the RI-plot method.

[0066] From the viewpoint of ozone resistance, the waxes contained in the first rubber composition, the second rubber composition, and the third rubber composition preferably have a content of normal alkanes having a linear structure of less than 95.0% by mass per 100% by mass of the wax. The content of normal alkanes having a linear structure is preferably 94.2% by mass or less, more preferably 93.0% by mass or less, and even more preferably 92.6% by mass or less. There is no particular lower limit, but it is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 88% by mass or more.

[0067] In particular, the waxes contained in the first rubber composition, the second rubber composition, and the third rubber composition contain, in terms of ozone resistance, normal alkanes (C 11 H 24 ~C 57 H 116 ) is preferably less than 95.0% by mass. The content of the normal alkanes having a linear structure and having from 11 to 57 carbon atoms is preferably 94.2% by mass or less, more preferably 93.0% by mass or less, and even more preferably 92.6% by mass or less. There is no particular lower limit, but it is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 88% by mass or more.

[0068] From the viewpoint of ozone resistance, the waxes contained in the first, second, and third rubber compositions contain a normal alkane having a linear structure and a branched isoalkane, which is a structural isomer of the normal alkane having a linear structure, and / or a cyclic alkane, which is a compound having the same number of carbon atoms as the normal alkane having a linear structure. The combined content of the branched isoalkane, which is a structural isomer of the normal alkane having a linear structure, and the cyclic alkane, which is a compound having the same number of carbon atoms as the normal alkane having a linear structure, is preferably greater than 6.0% by mass per 100% by mass of the wax. This combined content is preferably 6.2% by mass or more, more preferably 6.4% by mass or more, and even more preferably 6.5% by mass or more. While the upper limit is not particularly limited, it is preferably 20.0% by mass or less, more preferably 10.0% by mass or less, and even more preferably 9.0% by mass or less.

[0069] In particular, the wax contained in the first rubber composition, the second rubber composition, and the third rubber composition contains, from the viewpoint of ozone resistance, a normal alkane having a straight-chain structure, and an isoalkane having a branched structure which is a structural isomer of the normal alkane having a straight-chain structure and / or an alkane having a cyclic structure which is a compound having the same number of carbon atoms as the normal alkane having a straight-chain structure, and the wax contains an isoalkane having a branched structure (C 13 H 28 ~C 50 H 102 ) and alkanes having a cyclic structure (C 14 H 28 ~C 35 H 70) preferably exceeds 6.0% by mass. The total content is preferably 6.2% by mass or more, more preferably 6.4% by mass or more, and even more preferably 6.5% by mass or more. There is no particular upper limit, but it is preferably 20.0% by mass or less, more preferably 10.0% by mass or less, and even more preferably 9.0% by mass or less.

[0070] In this specification, the content of normal alkanes having a linear structure, the content of isoalkanes having a branched structure, and the content of alkanes having a cyclic structure in the wax may be values ​​obtained by the RI-plot method, or may be values ​​calculated from one or more waxes whose compositions, such as normal alkanes having a linear structure, isoalkanes having a branched structure, and alkanes having a cyclic structure, are known.

[0071] When the wax contained in the first rubber composition, the second rubber composition, and the third rubber composition contains the normal alkane having the linear structure, the average carbon number distribution of the normal alkane having the linear structure (the average carbon number of the normal alkanes contained in the rubber composition) is preferably 29 or more, more preferably 33 or more, and even more preferably 36 or more, and also preferably 45 or less, more preferably 42 or less, and even more preferably 40 or less.

[0072] When the wax contained in the first rubber composition, the second rubber composition, and the third rubber composition contains an isoalkane having a branched structure that is a structural isomer of the normal alkane having a linear structure, the average carbon number distribution of the isoalkane having a branched structure (the average carbon number of the isoalkane contained in the rubber composition) is preferably 25 or more, more preferably 30 or more, and even more preferably 33 or more, and also preferably 45 or less, more preferably 42 or less, and even more preferably 40 or less.

[0073] When the wax contained in the first rubber composition, the second rubber composition, and the third rubber composition contains an alkane having a cyclic structure, which is a compound having the same number of carbon atoms as the normal alkane having a linear structure, the average carbon number distribution of the alkane having a cyclic structure (the average carbon number of the isoalkane contained in the rubber composition) is preferably 20 or more, more preferably 24 or more, and even more preferably 27 or more, and also preferably 40 or less, more preferably 35 or less, and even more preferably 32 or less.

[0074] From the viewpoint of ozone resistance, the waxes contained in the first rubber composition, the second rubber composition, and the third rubber composition preferably contain isoalkanes having a branched structure and / or alkanes having a cyclic structure, each of which has five signals in the ΔRI ranges (1) to (5) below, when the chromatographic analysis method for the wax is used, in which the elution time (RI) of a chromatogram is plotted two-dimensionally with the elution time (RI) on the x-axis and the difference (ΔRI) between the integer part of the RI and the RI on the y-axis, and the isoalkanes having a branched structure and / or alkanes having a cyclic structure have a carbon number distribution within a certain range. (1) Components with a ΔRI value of -0.45 or more and less than -0.35 (2) Components with a ΔRI value of -0.35 or more and less than -0.20 (3) Components with a ΔRI value of -0.20 or more and -0.10 or less (4) Ingredients with a ΔRI value of +0.20 or more and less than +0.30 (5) Components with a ΔRI value of +0.30 or more and +0.40 or less

[0075] Here, the carbon number distribution of the isoalkane having a branched structure is, from the viewpoint of ozone resistance, 10 to 75 carbon atoms (C 10 ~C 75) range. From the viewpoint of ozone resistance, the carbon number distribution is preferably 12 or more, more preferably 13 or more, even more preferably 15 or more, and is preferably 65 or less, more preferably 60 or less, even more preferably 55 or less. The isoalkane having a branched structure may contain an isoalkane having a carbon number outside the range of the carbon number distribution, or may contain an isoalkane having a carbon number within the range of the carbon number distribution. From the viewpoint of ozone resistance, the carbon number distribution of the alkane having a cyclic structure is 10 to 75 carbon atoms (C 10 ~C 75 ) range. From the viewpoint of ozone resistance, the carbon number distribution is preferably 12 or more, more preferably 13 or more, even more preferably 15 or more, and is preferably 65 or less, more preferably 60 or less, even more preferably 55 or less. The alkane having a cyclic structure may include a cyclic alkane having a carbon number outside the range of the carbon number distribution, or may include a cyclic alkane having a carbon number within the range of the carbon number distribution.

[0076] The carbon number distribution of the wax can be measured by the following method. (carbon number distribution) The measurement is performed using a capillary GC as the measuring device and an aluminum-coated capillary column as the column under the conditions of helium carrier gas, flow rate of 4 ml / min, column temperature of 180 to 390°C, and temperature rise rate of 15°C / min.

[0077] The waxes contained in the first rubber composition, the second rubber composition, and the third rubber composition (for example, waxes in which a normal alkane having a linear structure contained in the wax and an isoalkane having a branched structure which is a structural isomer of the normal alkane having a linear structure and / or an alkane having a cyclic structure which is a compound having the same number of carbon atoms as the normal alkane having a linear structure are detected by the RI-plot method) can be prepared, for example, by using a wax obtained by mixing two or more known waxes containing the normal alkane having a linear structure and the isoalkane having a branched structure and / or the alkane having a cyclic structure.

[0078] Such known waxes are not particularly limited, and any wax commonly used in the tire industry can be suitably used. Examples include mineral waxes and plant-derived waxes. Mineral waxes refer to waxes derived from mineral resources such as oil and natural gas. Plant-derived waxes refer to waxes derived from natural resources such as plants. Mineral waxes are particularly preferred. Plant-derived waxes include rice wax, carnauba wax, and candelilla wax. Mineral waxes include paraffin wax, microcrystalline wax, and selected special waxes thereof, with paraffin wax being preferred. The wax according to this embodiment does not contain stearic acid. Commercially available waxes from Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt Co., Ltd., and the like can be used. These waxes may be used alone or in combination of two or more. As described above, for example, by combining two or more waxes, a wax having a desired carbon number distribution can be prepared.

[0079] In the first, second and third rubber compositions, from the viewpoint of ozone resistance, the wax content (total amount of wax) is preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more, even more preferably 1.0 part by mass or more, and particularly preferably 1.5 parts by mass or more, per 100 parts by mass of the rubber component. The content is preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, and even more preferably 2.0 parts by mass or less.

[0080] The first rubber composition, the second rubber composition, and the third rubber composition may contain a filler. In the first, second, and third rubber compositions, usable fillers are not particularly limited, and materials known in the rubber field can be used. Examples include inorganic fillers such as carbon black, silica, calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, and mica, and poorly dispersible fillers such as biochar, microfibrillated plant fiber, short-fiber cellulose, and gel-like compounds. Among these, at least one of carbon black and silica is preferably included. The above fillers may be used alone or in combination of two or more.

[0081] The carbon black that can be used in the first, second, and third rubber compositions is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. The raw material for carbon black may be a biomass material such as lignin or vegetable oil, or pyrolysis oil obtained by pyrolysis of waste tires. Carbon black may be produced by combustion, such as in a furnace process, by hydrothermal carbonization (HTC), or by pyrolysis of methane, such as in a thermal black process. Commercially available carbon black products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., and Columbia Carbon Co., Ltd. These carbon blacks may be used alone or in combination.

[0082] The nitrogen adsorption specific surface area (N2SA) of carbon black is 20m 2 / g or more is preferable, and 30m 2 / g or more is more preferable, and 40m 2 / g or more is more preferable. 2 / g or less is preferable, and 130m 2 / g or less is more preferable, and 120m 2 Within the above range, the effect tends to be better. The nitrogen adsorption specific surface area of ​​carbon black can be determined according to JIS K6217-2:2001.

[0083] The silica that can be used in the first, second, and third rubber compositions is not particularly limited, and can be, for example, silica prepared by a dry process (anhydrous silica) or silica prepared by a wet process (hydrated silica), which are commonly used in the tire industry. The raw material for the silica is not particularly limited, and can be, for example, a mineral-derived raw material such as quartz, a biological raw material such as rice husk (for example, silica made from a biomass material such as rice husk), or silica recycled from a silica-containing product. Among these, hydrated silica prepared by a wet process is preferred because it contains a large number of silanol groups. These silicas can be used alone or in combination of two or more types.

[0084] Silica made from biomass materials can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and then reacting the silicate with sulfuric acid in the same manner as conventional wet-process silica to produce a silicon dioxide precipitate, which is then filtered, washed with water, dried, and pulverized.

[0085] Silica recycled from silica-containing products can be, for example, silica recovered from products containing silica, such as electronic components such as semiconductors, tires, desiccants, and filtering materials such as diatomaceous earth. The recovery method is not particularly limited, and examples include thermal decomposition and decomposition by electromagnetic waves. Among these, silica recovered from electronic components such as semiconductors or tires is preferred.

[0086] When silica crystallizes, it becomes insoluble in water, and its component, silicic acid, cannot be utilized. By controlling the combustion temperature and duration, it is possible to suppress the crystallization of silica in rice husk ash (see, for example, JP 2009-2594 A and Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222).

[0087] Amorphous silica extracted from rice husks may be commercially available from Wilmar Co., Ltd., etc.

[0088] The nitrogen adsorption specific surface area (N2SA) of the silica is preferably 50 m 2 / g or more, more preferably 100m 2 / g or more, more preferably 150m 2 The upper limit of the N2SA of silica is not particularly limited, but is preferably 350 m 2 / g or less, more preferably 300m 2 / g or less, more preferably 250m 2 Within the above range, there is a tendency for the effect to be better obtained. The N2SA of silica is a value measured by the BET method in accordance with ASTM D3037-93.

[0089] When the first rubber composition, the second rubber composition, and the third rubber composition contain carbon black, the carbon black content is preferably 5 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 150 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 80 parts by mass or less. Within the above ranges, better effects tend to be obtained.

[0090] When the first rubber composition, the second rubber composition, and the third rubber composition contain silica, the content of silica is preferably 5 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 150 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 80 parts by mass or less. Within the above ranges, the effect tends to be more favorably obtained.

[0091] In the first, second and third rubber compositions, the filler content (total amount of fillers such as carbon black and silica) is preferably 5 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 60 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 150 parts by mass or less, more preferably 120 parts by mass or less, and even more preferably 100 parts by mass or less. Within the above ranges, better effects tend to be obtained.

[0092] When the first rubber composition, the second rubber composition, and the third rubber composition contain silica, they may further contain a silane coupling agent. The silane coupling agent is not particularly limited, and those known in the rubber field can be used, for example, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, bis(4-trimethoxysilylbutyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)disulfide, bis(4-triethoxysilylbutyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, bis(4-trimethoxysilylbutyl)disulfide, 3-trimethoxysilylpropyl-N, Examples include sulfide-based compounds such as N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, and 3-triethoxysilylpropyl methacrylate monosulfide; mercapto-based compounds such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and NXT and NXT-Z manufactured by Momentive; vinyl-based compounds such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based compounds such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based compounds such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based compounds such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based compounds such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Commercially available products include those from Degussa, Momentive, Shin-Etsu Silicones Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., and Dow Corning Toray Co., Ltd. These may be used alone or in combination of two or more.

[0093] In the first, second, and third rubber compositions, the content of the silane coupling agent is preferably 0.1 parts by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of silica. The upper limit of the content is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less. Within the above ranges, the effect tends to be more favorable.

[0094] The first rubber composition, the second rubber composition, and the third rubber composition may contain a plasticizer (softener). In this specification, the term "plasticizer" refers to a material that imparts plasticity to rubber components, and includes both plasticizers that are liquid (liquid state) at room temperature (25°C) and plasticizers that are solid at room temperature (25°C). Examples of plasticizers include resin components, oils, liquid polymers, and ester-based plasticizers. These plasticizers may be derived from petroleum, biomass, or naphtha recycled from rubber or non-rubber products. Low-molecular-weight hydrocarbon components obtained by pyrolysis and extraction of used tires or products containing various components may also be used as plasticizers. These plasticizers may be used alone or in combination. In this specification, wax is not included in the plasticizer.

[0095] Specific examples of the plasticizer include oils, liquid polymers, resins, etc. These may be used alone or in combination of two or more.

[0096] Examples of oils include process oil, vegetable oil, and animal oil. Examples of process oils include paraffinic process oil (mineral oil), naphthenic process oil, and aromatic process oil. Specific examples of process oils include mild extracted solvate (MES), distillate aromatic extract (DAE), treated distillate aromatic extract (TDAE), treated residual aromatic extract (TRAE), and residual aromatic extract (RAE). Furthermore, as an environmental measure, process oils with a low content of polycyclic aromatic compounds (PCA) can also be used. Examples of low-PCA process oils include MES, TDAE, and heavy naphthenic oil. Furthermore, from the perspective of life cycle assessment, refined waste oil from rubber mixers and engines, or waste cooking oil from restaurants, may also be used.

[0097] As used herein, examples of vegetable oils include linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grapeseed oil, and Japan wax. Further examples of vegetable oils include refined oils (such as salad oil) obtained by refining the above-mentioned oils, interesterified oils obtained by interesterifying the above-mentioned oils, hardened oils obtained by hydrogenating the above-mentioned oils, thermally polymerized oils obtained by thermally polymerizing the above-mentioned oils, oxidatively polymerized oils obtained by oxidizing the above-mentioned oils, and waste edible oils recovered from edible oils and the like. Vegetable oils may be liquid or solid at room temperature (25°C). These vegetable oils may be used alone or in combination of two or more.

[0098] The vegetable oil according to this embodiment preferably contains acylglycerol, and more preferably triacylglycerol. In this specification, acylglycerol refers to a compound in which a hydroxyl group of glycerin is ester-bonded to a fatty acid. The acylglycerol is not particularly limited and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, the acylglycerol may be a monomer, a dimer, or a polymer (trimer or higher). Dimer or higher acylglycerols can be obtained by thermal polymerization, oxidative polymerization, or the like. Furthermore, the acylglycerol may be liquid or solid at room temperature (25°C).

[0099] The method for confirming whether the rubber composition contains the acylglycerol is not particularly limited, but may be any of the following: 1 For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at room temperature (25°C) for 24 hours, and after removing the rubber composition, the rubber composition is immersed in deuterated chloroform at room temperature. 1 When H-NMR was measured, signals were observed around 5.26 ppm, 4.28 ppm, and 4.15 ppm when the signal of tetramethylsilane (TMS) was set at 0.00 ppm. These signals are presumed to be signals derived from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atoms of the ester group. In this paragraph, "around" refers to a range of ±0.10 ppm.

[0100] The fatty acid is not particularly limited and may be either an unsaturated fatty acid or a saturated fatty acid. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0101] Among these, it is desirable that the fatty acid contains a fatty acid with few double bonds, i.e., a saturated fatty acid or a monounsaturated fatty acid, and oleic acid is preferred. As a vegetable oil containing such a fatty acid, for example, vegetable oil containing a saturated fatty acid or a monounsaturated fatty acid may be used, or vegetable oil modified by ester exchange or the like may be used. Furthermore, in order to produce vegetable oil containing such a fatty acid, plants may be improved by breeding, genetic modification, genome editing, or the like.

[0102] As the oil, for example, commercially available oils from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoi Co., Ltd., H&R Corporation, Toyokuni Oil Mills Co., Ltd., Fuji Kosan Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0103] Examples of the liquid polymer include liquid diene polymers (liquid rubbers) and liquid farnesene polymers at 25°C. Examples of liquid rubber include liquid styrene butadiene copolymers (liquid SBRs), liquid butadiene polymers (liquid BRs), liquid isoprene polymers (liquid IRs), liquid styrene isoprene copolymers (liquid SIRs), liquid styrene butadiene styrene block copolymers (liquid SBS block polymers), and liquid styrene isoprene styrene block copolymers (liquid SIS block polymers). The terminals or main chains of these may be modified with polar groups. Hydrogenated versions of these compounds can also be used.

[0104] The liquid diene polymer has a weight average molecular weight (Mw) of 1.0×10 in terms of polystyrene as measured by gel permeation chromatography (GPC). 3 ~5.0×10 4 Preferably, it is 3.0 × 10 3 ~1.5×10 4 The lower or upper limit of Mw of the liquid diene polymer may be 4,500 or 8,500. In this specification, the Mw of the liquid diene polymer is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0105] As the liquid diene polymer, for example, products available from Sartomer Co., Ltd., Kuraray Co., Ltd., etc. can be used.

[0106] The resin may be a resin commonly used in tire compounds, and may be liquid or solid at room temperature (25°C). Examples include aromatic vinyl polymers, coumarone-indene resins, coumarone resins, indene resins, phenolic resins, rosin resins, petroleum resins, terpene resins, and acrylic resins. The resin may also be a hydrogenated resin (hydrogenated resin). These may be used alone or in combination of two or more. The resin itself may also be a copolymer of monomer components derived from multiple sources. Among these, aromatic vinyl polymers, petroleum resins, terpene resins, and hydrogenated resins thereof are preferred.

[0107] When a resin that is solid at room temperature is used, the softening point of the resin is preferably 50° C. or higher, more preferably 55° C. or higher, even more preferably 60° C. or higher, and particularly preferably 85° C. or higher. Also, the softening point is preferably 160° C. or lower, more preferably 150° C. or lower, even more preferably 140° C. or lower, and particularly preferably 100° C. or lower. Within the above range, better effects tend to be obtained. When the resin is liquid at room temperature, the softening point is preferably 20°C or lower, more preferably 10°C or lower, and even more preferably 0°C or lower. In the case of hydrogenated resins, it is desirable that the softening point is the same as above. The softening point of the resin is the temperature at which the ball drops when the softening point specified in JIS K6220-1:2001 is measured using a ring and ball softening point tester.

[0108] The aromatic vinyl polymer is a polymer containing an aromatic vinyl monomer as a constituent unit. For example, it may be a resin obtained by polymerizing α-methylstyrene and / or styrene, and specifically may be a homopolymer of styrene (styrene resin), a homopolymer of α-methylstyrene (α-methylstyrene resin), a copolymer of α-methylstyrene and styrene, or a copolymer of styrene and another monomer.

[0109] The coumarone-indene resin is a resin containing coumarone and indene as the main monomer components constituting the resin skeleton (main chain). Other monomer components contained in the skeleton besides coumarone and indene include styrene, α-methylstyrene, methylindene, vinyltoluene, etc.

[0110] The coumarone resin is a resin containing coumarone as a main monomer component constituting the skeleton (main chain) of the resin.

[0111] The indene resin is a resin containing indene as a main monomer component constituting the skeleton (main chain) of the resin.

[0112] The phenolic resin may be a known polymer obtained by reacting phenol with an aldehyde such as formaldehyde, acetaldehyde, or furfural in the presence of an acid or alkali catalyst. Of these, those obtained by reacting with an acid catalyst (such as novolac phenolic resin) are preferred.

[0113] Examples of the rosin resin include rosin-based resins such as natural rosin, polymerized rosin, modified rosin, ester compounds thereof, and hydrogenated products thereof.

[0114] Examples of the petroleum resin include C5 resin, C9 resin, C5 / C9 resin, dicyclopentadiene (DCPD) resin, C9 / DCPD resin, and hydrogenated versions of these. Of these, DCPD resin, hydrogenated DCPD resin, C9 / DCPD resin, and C9 / hydrogenated DCPD resin are preferred.

[0115] The terpene resin is a polymer containing terpene as a structural unit. Examples include polyterpene resins obtained by polymerizing terpene compounds and aromatic-modified terpene resins obtained by polymerizing terpene compounds and aromatic compounds. Examples of aromatic-modified terpene resins include terpene phenol resins made from terpene compounds and phenolic compounds, terpene styrene resins made from terpene compounds and styrene compounds, and terpene phenol styrene resins made from terpene compounds, phenolic compounds, and styrene compounds. Examples of terpene compounds include α-pinene and β-pinene, phenolic compounds include phenol and bisphenol A, and aromatic compounds include styrene compounds (styrene, α-methylstyrene, etc.). Among these, aromatic-modified terpene resins are preferred.

[0116] The acrylic resin is a polymer containing an acrylic monomer as a constituent unit. For example, a styrene-acrylic resin having a carboxyl group and obtained by copolymerizing an aromatic vinyl monomer component with an acrylic monomer component can be used. Among them, a solvent-free carboxyl-containing styrene-acrylic resin can be preferably used.

[0117] Examples of the resins that can be used include products from Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical Company, ExxonMobil, KRATON, Nitto Chemical Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., and Taoka Chemical Co., Ltd.

[0118] From the viewpoint of sustainability, it is desirable to use the above-mentioned plant-derived plasticizers such as plant-derived oils and farnesene-based polymers as the plasticizer.

[0119] Farnesene polymers are polymers obtained by polymerizing farnesene and contain structural units based on farnesene. Farnesene has isomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecatetraene) and β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecatriene), but (E)-β-farnesene, which has the following structure, is preferred. [ka]

[0120] The farnesene polymer may be a homopolymer of farnesene (farnesene homopolymer) or a copolymer of farnesene and a vinyl monomer (farnesene-vinyl monomer copolymer). These may be used alone or in combination of two or more. Among these, a copolymer of farnesene and a vinyl monomer is preferred.

[0121] Examples of vinyl monomers include aromatic vinyl compounds such as styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-tert-butylstyrene, 5-tert-butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-tert-butylstyrene, 3-tert-butylstyrene, 4-tert-butylstyrene, vinylxylene, vinylnaphthalene, vinyltoluene, vinylpyridine, diphenylethylene, and tertiary amino group-containing diphenylethylene, as well as conjugated diene compounds such as butadiene and isoprene. These may be used alone or in combination of two or more. Among these, butadiene is preferred. That is, the farnesene-vinyl monomer copolymer is preferably a copolymer of farnesene and butadiene (farnesene-butadiene copolymer).

[0122] In the farnesene-vinyl monomer copolymer, the copolymerization ratio by mass of farnesene and vinyl monomer (farnesene / vinyl monomer) is preferably 40 / 60 to 90 / 10.

[0123] The farnesene polymer preferably has a weight average molecular weight (Mw) of 3,000 or more and 300,000 or less. The Mw of the farnesene polymer is preferably 8,000 or more, more preferably 10,000 or more, and is preferably 100,000 or less, more preferably 60,000 or less, and even more preferably 50,000 or less. Within the above ranges, the effects tend to be more favorably obtained.

[0124] The farnesene polymer may be in a liquid state or a solid state at room temperature (25° C.), with liquid farnesene polymers being preferred.

[0125] When the first rubber composition, the second rubber composition, and the third rubber composition contain a plasticizer, the content of the plasticizer (total amount of plasticizer) is preferably 3 parts by mass or more, more preferably 6 parts by mass or more, and even more preferably 8 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less. Within the above ranges, better effects tend to be obtained. The plasticizer content includes the amount of oil and resin contained in the oil-extended rubber and resin-extended rubber.

[0126] The first rubber composition, the second rubber composition, and the third rubber composition may further contain vulcanized rubber particles. The vulcanized rubber particles are particles made of vulcanized rubber, and specifically, rubber powder as specified in JIS K 6316:2017 can be used. From the standpoint of environmental considerations and cost, recycled rubber powder produced from crushed waste tires is preferred. These may be used alone or in combination of two or more types.

[0127] The vulcanized rubber particles are not particularly limited, and may be unmodified vulcanized rubber particles or modified vulcanized rubber particles.

[0128] As commercially available vulcanized rubber particles, for example, products from Lehigh Corporation, Muraoka Rubber Industries Co., Ltd., etc. can be used.

[0129] In the first, second and third rubber compositions, the content of the vulcanized rubber particles is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less. Within the above ranges, the effects tend to be better obtained.

[0130] The first rubber composition, the second rubber composition and the third rubber composition preferably contain an antioxidant from the viewpoints of crack resistance, ozone resistance and the like.

[0131] The antioxidant is not particularly limited, and examples thereof include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), and N,N'-ditolyl-p-phenylenediamine. p-phenylenediamine antioxidants such as N-isopropyl-N'-phenyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline antioxidants such as 2,2,4-trimethyl-1,2-dihydroquinoline polymers; monophenol antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; and bis-, tris-, and polyphenol antioxidants such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. Among these, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, and polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. Commercially available products that can be used include those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis, etc.

[0132] In the first, second and third rubber compositions, the content of the antioxidant is preferably 0.5 parts by mass or more, more preferably 1.5 parts by mass or more, and even more preferably 2.5 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 7.0 parts by mass or less, more preferably 5.0 parts by mass or less.

[0133] The first rubber composition, the second rubber composition and the third rubber composition preferably contain stearic acid. In the first, second and third rubber compositions, the content of stearic acid is preferably 1.0 part by mass or more, more preferably 2.5 parts by mass or more, and preferably 10.0 parts by mass or less, more preferably 5.0 parts by mass or less, per 100 parts by mass of the rubber component.

[0134] As the stearic acid, conventionally known products can be used, for example, products available from NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Industries, Ltd., Chiba Fatty Acid Co., Ltd., etc.

[0135] The first rubber composition, the second rubber composition and the third rubber composition preferably contain zinc oxide. In the first rubber composition, the second rubber composition, and the third rubber composition, the content of zinc oxide is preferably 1.0 part by mass or more, more preferably 1.5 parts by mass or more, and is preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, per 100 parts by mass of the rubber component.

[0136] As the zinc oxide, conventionally known products can be used, for example, products from Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. can be used.

[0137] The first rubber composition, the second rubber composition and the third rubber composition preferably contain sulfur. In the first, second, and third rubber compositions, the sulfur content is preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more, and even more preferably 1.0 part by mass or more, per 100 parts by mass of the rubber component. The content is preferably 3.5 parts by mass or less, more preferably 3.0 parts by mass or less, and even more preferably 2.5 parts by mass or less. Within the above ranges, the effects tend to be more favorable.

[0138] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur, etc., which are commonly used in the rubber industry. Commercially available products include those from Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexis Corporation, Nippon Kanzuri Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. These may be used alone or in combination of two or more.

[0139] The first rubber composition, the second rubber composition and the third rubber composition preferably contain a vulcanization accelerator. In the first, second and third rubber compositions, the content of the vulcanization accelerator is not particularly limited and may be freely determined according to the desired vulcanization rate and crosslink density, but is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, per 100 parts by mass of the rubber component. The upper limit is preferably 8.0 parts by mass or less, more preferably 6.0 parts by mass.

[0140] The type of vulcanization accelerator is not particularly limited, and commonly used ones can be used. Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiazyl sulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, Nt-butyl-2-benzothiazolyl sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, di-orthotolylguanidine, and orthotolylbiguanidine. These may be used alone or in combination of two or more. Among these, sulfenamide-based, guanidine-based and benzothiazole-based vulcanization accelerators are preferred.

[0141] In addition to the above components, the first rubber composition, the second rubber composition, and the third rubber composition may contain compounding agents generally used in the tire industry, such as materials such as a mold release agent, as appropriate.

[0142] In this specification, various materials containing carbon atoms (e.g., rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) may be derived from atmospheric carbon dioxide. As a method for obtaining the above-mentioned compound from carbon dioxide, carbon dioxide may be directly converted, or methane obtained through a methanation process in which methane is synthesized from carbon dioxide may be converted.

[0143] The first rubber composition, the second rubber composition, and the third rubber composition can be produced, for example, by kneading the components using a rubber kneading device such as an open roll or a Banbury mixer, and then vulcanizing the mixture.

[0144] Regarding kneading conditions, in the base kneading step in which additives other than the crosslinking agent (vulcanizing agent) and vulcanization accelerator are kneaded, the kneading temperature is preferably 100°C or higher, more preferably 120°C or higher, and preferably 180°C or lower, more preferably 170°C or lower. In the finish kneading step in which the vulcanizing agent and vulcanization accelerator are kneaded, the kneading temperature is preferably 80°C or higher, and preferably 120°C or lower, more preferably 110°C or lower. Furthermore, the composition kneaded with the vulcanizing agent and vulcanization accelerator is usually subjected to a vulcanization treatment such as press vulcanization. The vulcanization temperature is preferably 140°C or higher, more preferably 150°C or higher, and preferably 190°C or lower, more preferably 185°C or lower.

[0145] The above rubber compositions (first rubber composition, second rubber composition, third rubber composition) can be used as rubber compositions for tire components. Examples of the tire components include treads (cap treads, base treads, etc.), sidewalls, clinches, bead apexes, breaker cushion rubbers, carcass cord covering rubbers, insulation, chafers, inner liners, side reinforcing layers of run-flat tires, etc. Among these, treads, sidewalls, etc. are preferred.

[0146] The above tire is manufactured by a conventional method using the above rubber compositions (first rubber composition, second rubber composition, third rubber composition). That is, a composition containing various additives as necessary is extruded to match the shapes of various tire components in the unvulcanized state, molded by a conventional method on a tire building machine, and laminated together with other tire components to form an unvulcanized tire, which is then heated and pressurized in a vulcanizer to manufacture the tire.

[0147] The tire is not particularly limited, and examples thereof include pneumatic tires, solid tires, airless tires, etc. Among these, pneumatic tires are preferred.

[0148] The above-mentioned tires are suitably used as passenger car tires, large passenger car tires, large SUV tires, truck and bus tires, motorcycle tires, racing tires, winter tires (studless tires, snow tires, studded tires), all-season tires, run-flat tires, aircraft tires, mining tires, etc. [Example]

[0149] Below, examples (embodiments) that are considered preferable for implementation will be shown, but the scope of the present invention is not limited to the examples.

[0150] The various chemicals used in tire manufacturing are summarized below. If necessary, the chemicals may be refined according to standard methods. NR:TSR20 BR: BR150B (cis content 97% by mass) manufactured by Ube Industries, Ltd. Carbon black: Diablack N220 (Mitsubishi Chemical Corporation, N2SA114m 2 / g) Wax 1: Wax 1 below Wax 2: Wax 2 below Wax 3: Wax 3 below Stearic acid: NOF Corporation's "Tsubaki" stearic acid Zinc oxide: Zinc oxide No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: HK-200-5 (powdered sulfur) manufactured by Hosoi Chemical Industry Co., Ltd. Vulcanization accelerator: Noccela CZ (N-cyclohexyl-2-benzothiazolyl sulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0151] (Wax 1) A: normal alkane (C 11 -C 35 ), components with ΔRI values ​​of -0.05 or more and +0.05 or less B: Saturated alkanes with branched structures 1 (C 14 -C 25 ), components with ΔRI values ​​of -0.45 or more and less than -0.35 C: saturated alkane with branched structure 2 (C 13 -C 24 ), components with ΔRI values ​​of -0.35 or more and less than -0.20 D: Unsaturated alkane with a terminal cyclic structure 1 (C 14 -C 21 ), components with ΔRI values ​​of -0.20 or more and -0.10 or less A wax containing the above components with a content (mass%) of A / B / C / D=94 / 2 / 3 / 1.

[0152] (Wax 2) A: normal alkane (C 20 -C 47 ), components with ΔRI values ​​of -0.05 or more and +0.05 or less C: saturated alkane with branched structure 2 (C 22 -C 43 ), components with ΔRI values ​​of -0.35 or more and less than -0.20 A wax containing the above components with a content ratio (mass%) of A / B=95 / 5.

[0153] (Wax 3) A: normal alkane (C 20 -C 57 ), components with ΔRI values ​​of -0.05 or more and +0.05 or less B: Saturated alkanes with branched structures 1 (C 23 -C 51 ), components with ΔRI values ​​of -0.45 or more and less than -0.35 C: saturated alkane with branched structure 2 (C 24 -C 50 ), components with ΔRI values ​​of -0.35 or more and less than -0.20 D: Unsaturated alkane with a terminal cyclic structure 1 (C 28 -C 35 ), components with ΔRI values ​​of -0.20 or more and -0.10 or less E: Unsaturated alkane 2 (C 25 -C 35 ,Ingredients with ΔRI values ​​of +0.20 or more and less than +0.30 F: Unsaturated alkane 3 (C 25 -C 36 ), components with ΔRI values ​​of +0.30 or more and +0.40 or less The wax contains the following components with a content (mass%) of A / B / C / D / E / F=90 / 3 / 4 / 1 / 1 / 1.

[0154] <Preparation of vulcanized rubber composition> According to the formulation shown in Table 1, materials other than sulfur and vulcanization accelerator are kneaded for 5 minutes at 150°C using a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd. to obtain a kneaded mixture. Sulfur and a vulcanization accelerator are added to the kneaded mixture, and the mixture is kneaded for 5 minutes at 80°C using an open roll to obtain an unvulcanized rubber composition. The unvulcanized rubber composition is vulcanized at 170°C for 12 minutes to obtain a vulcanized rubber composition.

[0155] Assuming vulcanized rubber compositions whose formulations were changed to formulations 1 to 6 according to Table 1, the results calculated based on the following evaluation methods are shown in Table 1.

[0156] <Ozone resistance test> The vulcanized rubber compositions (compounds 1 to 6) are evaluated for ozone resistance by observing the state of cracks under conditions of an ozone concentration of 50 pphm, a temperature of 40°C, and an elongation strain of 20%, based on JIS K 6259 "Vulcanized rubber and thermoplastic rubber - Determination of ozone resistance." The measurement time is 24 hours, and crack growth is evaluated every 3 hours. The ozone resistance index is calculated as an initial value of 100, and decreases as the degree of deterioration progresses (normalized by the number of surface cracks). The smaller the decrease in the value, the better the ozone resistance.

[0157] <Analysis of wax alone and rubber composition> (wax alone) For the above waxes 1, 2, and 3, the extracted waxes are subjected to gas chromatography (GC), and the resulting chromatograms are analyzed using the RI-plot method, which plots the chromatogram elution time (RI) on the x-axis and the difference between the integer part of RI and the RI (ΔRI) on the y-axis, to create a scatter diagram. (Rubber composition) The wax is extracted from each of the vulcanized rubber compositions (compounds 1 to 6) using an organic solvent (cyclohexane). The extracted wax is subjected to gas chromatography (GC), and the resulting chromatogram is analyzed using the RI-plot method, which plots the chromatogram elution time (RI) on the x-axis and the difference between the integer part of RI and the RI (ΔRI) on the y-axis, to create a two-dimensional scatter diagram.

[0158] [Table 1]

[0159] Regarding the analysis of the above waxes alone, the scatter diagram obtained from the waxes alone identifies that the waxes 1, 2, and 3 alone contain the above-mentioned components A, B, C, D, E, and F, respectively. Regarding the analysis of the above rubber compositions, from the scatter diagram obtained from the extracted waxes of the rubber compositions of Compounds 1 to 6, it is determined that the alkane compositions and average carbon number distribution of A (normal alkane), B (saturated alkane 1 having a branched structure), C (saturated alkane 2 having a branched structure), D (unsaturated alkane 1 having a terminal cyclic structure), E (unsaturated alkane 2 having a terminal cyclic structure), and F (unsaturated alkane 3 having a terminal cyclic structure) out of 100% by mass of the total wax contained in the rubber compositions of Compounds 1 to 6 are those listed in Table 1.

[0160] Regarding the ozone resistance test, the ozone resistance of compounds 1 to 6 with different degradation times was evaluated, and the relationship between the obtained ozone resistance index and the scatter diagram obtained by the RI-plot method for compounds 1 to 6 shows that the rubber compositions of compounds 1 to 4, which contain wax with a high content of isoalkanes with a branched structure or alkanes with a cyclic structure, guarantee ozone resistance over a long period of time.

[0161] The present invention (1) is a method for analyzing a wax or rubber composition using chromatography, The method for analyzing a wax or rubber composition is characterized in that the RI-plot method is used for the chromatographic analysis.

[0162] The present invention (2) is a method for analyzing a wax or rubber composition according to the present invention (1), wherein the RI-plot method is a two-dimensional plotting method in which the elution time (RI) of a chromatogram is plotted on the x-axis and the difference between the integer part of RI and the RI (ΔRI) is plotted on the y-axis.

[0163] The present invention (3) is a method for detecting normal alkanes having a linear structure, isoalkanes having a branched structure and / or alkanes having a cyclic structure contained in a wax by the RI-plot method, the isoalkane having a branched structure is a structural isomer of the normal alkane having a linear structure, This is the method for analyzing a wax or rubber composition according to the present invention (1) or (2), wherein the alkane having a cyclic structure is a compound having the same number of carbon atoms as the normal alkane having a straight-chain structure.

[0164] The present invention (4) is a rubber composition containing a rubber component and a wax, The rubber composition is one in which the wax has a signal in a predetermined ΔRI region when the chromatographic analysis method for the wax is performed using the RI-plot method, which plots the elution time (RI) of a chromatogram on the x-axis and the difference between the integer part of the RI and the RI (ΔRI) on the y-axis, and creates a two-dimensional plot.

[0165] The present invention (5) is a rubber composition containing a rubber component and a wax, The wax contains a normal alkane having a linear structure, an isoalkane having a branched structure, and / or an alkane having a cyclic structure, the isoalkane having a branched structure is a structural isomer of the normal alkane having a linear structure, the alkane having a cyclic structure is a compound having the same number of carbon atoms as the normal alkane having a linear structure, In the rubber composition, the content of the normal alkane having a linear structure is less than 95% by mass relative to 100% by mass of the wax.

[0166] The present invention (6) is a rubber composition containing a rubber component and a wax, When the chromatographic analysis of the wax is performed using an RI-plot method in which the elution time (RI) of a chromatogram is plotted on the x-axis and the difference between the integer part of RI and the RI (ΔRI) is plotted on the y-axis, the wax contains isoalkanes having a branched structure and / or alkanes having a cyclic structure, which have five signals in the ΔRI regions of the following (1) to (5): The rubber composition has a carbon number distribution within a certain range, in which the isoalkane having a branched structure and / or the alkane having a cyclic structure has a carbon number distribution within a certain range. (1) Components with a ΔRI value of -0.45 or more and less than -0.35 (2) Components with a ΔRI value of -0.35 or more and less than -0.20 (3) Components with a ΔRI value of -0.20 or more and -0.10 or less (4) Ingredients with a ΔRI value of +0.20 or more and less than +0.30 (5) Components with a ΔRI value of +0.30 or more and +0.40 or less

[0167] The present invention (7) is the rubber composition according to the present invention (6), wherein the carbon number distribution of the isoalkane having a branched structure and / or the alkane having a cyclic structure is in the range of 10 to 55 carbon atoms.

Claims

1. A method for analyzing a wax or rubber composition using chromatography, comprising: A method for analyzing a wax or rubber composition, characterized in that an RI-plot method is used for the chromatographic analysis.

2. 2. The method for analyzing a wax or rubber composition according to claim 1, wherein the RI-plot method is a technique for two-dimensionally plotting a chromatogram with the elution time (RI) of the chromatogram on the x-axis and the difference (ΔRI) between the integer part of the RI and the RI on the y-axis.

3. Detect normal alkanes having a linear structure, isoalkanes having a branched structure and / or alkanes having a cyclic structure contained in the wax by the RI-plot method; the isoalkane having a branched structure is a structural isomer of the normal alkane having a linear structure, 3. The method for analyzing a wax or rubber composition according to claim 1, wherein the alkane having a cyclic structure is a compound having the same number of carbon atoms as the normal alkane having a straight-chain structure.

4. A rubber composition comprising a rubber component and a wax, The rubber composition is one in which the wax has a signal in a predetermined ΔRI region when an RI-plot method is used as a method for analyzing the wax by chromatography, in which the elution time (RI) of a chromatogram is plotted on the x-axis and the difference between the integer part of RI and the RI (ΔRI) is plotted on the y-axis to create a two-dimensional plot.

5. A rubber composition comprising a rubber component and a wax, the wax contains a normal alkane having a linear structure, an isoalkane having a branched structure, and / or an alkane having a cyclic structure; the isoalkane having a branched structure is a structural isomer of the normal alkane having a linear structure, the alkane having a cyclic structure is a compound having the same number of carbon atoms as the normal alkane having a linear structure, The rubber composition has a content of the normal alkane having a linear structure of less than 95% by mass relative to 100% by mass of the wax.

6. A rubber composition comprising a rubber component and a wax, When the chromatographic analysis of the wax is performed using an RI-plot method in which a chromatogram is plotted two-dimensionally with the elution time (RI) of the chromatogram on the x-axis and the difference (ΔRI) between the integer part of the RI and the RI on the y-axis, the wax contains isoalkanes having a branched structure and / or alkanes having a cyclic structure, which have five signals in the ΔRI regions of the following (1) to (5): A rubber composition in which the isoalkane having a branched structure and / or the alkane having a cyclic structure has a carbon number distribution within a certain range. (1) A component having a ΔRI value of -0.45 or more and less than -0.35 (2) Components with a ΔRI value of -0.35 or more and less than -0.20 (3) Components with a ΔRI value of -0.20 or more and -0.10 or less (4) Components with a ΔRI value of +0.20 or more and less than +0.30 (5) Components with a ΔRI value of +0.30 or more and +0.40 or less

7. The rubber composition according to claim 6, wherein the carbon number distribution of the isoalkane having a branched structure and / or the alkane having a cyclic structure is in the range of 10 to 75 carbon atoms.

Images