Rubber composition, and rubber products and hoses obtained using the same.

Abstract

To provide: a rubber composition which is capable of reducing the proportion of petroleum-derived starting materials used therein without causing the deterioration of the properties required for rubber products such as elongation properties; and a rubber product and a hose, each of which is obtained using the rubber composition.SOLUTION: The present invention provides a rubber composition which contains the components (A)-(D): (A) a rubber-based polymer; (B) a plant-derived filler; (C) carbon black; (D) diacetyl monododecanoyl glyceride.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a rubber composition, a rubber product, and a hose obtained using the same, and more particularly, to a rubber composition that employs a raw material derived from non-petroleum in order to achieve carbon neutrality, and a rubber product and a hose obtained using the same.

Background Art

[0002] Conventionally, carbon black and the like derived from petroleum have been used as general reinforcing materials for rubber products (see, for example, Patent Document 1). Among these, in response to the global movement towards carbon neutrality in recent years, in rubber products as well, reducing the proportion of raw materials derived from petroleum and adopting raw materials derived from non-petroleum have been under consideration. As part of this, for example, using plant-derived fillers such as cellulose fibers as fillers for rubber products has been under consideration (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, plant-derived fillers generally have many polar groups (hydroxyl groups) on the surface compared to carbon black, making them difficult to disperse in rubber. As a result, the elongation physical properties in rubber products are significantly inhibited, and when using plant-derived fillers, problems such as difficulty in expressing the performance required for rubber products are likely to occur. Furthermore, simply reducing the proportion of petroleum-derived raw materials can negatively affect the reinforcing properties and vulcanization shrinkage of rubber products.

[0005] This invention has been made in view of these circumstances, and aims to provide a rubber composition that can reduce the proportion of petroleum-derived raw materials without impairing the performance required of rubber products, such as elasticity, and rubber products and hoses obtained using the same. [Means for solving the problem]

[0006] The inventors diligently conducted research to solve the aforementioned problems. In the course of this research, the inventors investigated preparing a rubber composition by using a rubber polymer (A) in combination with a plant-derived filler (B) and carbon black (C), and further adding diacetyl monodecanoyl glyceride (D), a plant-derived plasticizer that facilitates the dispersion of the plant-derived filler (B) and carbon black (C), to the rubber polymer (A). As a result, they found that the dispersibility of the plant-derived filler (B) and carbon black (C) was improved, the decrease in stretchability could be improved, and furthermore, the proportion of petroleum-derived raw materials could be reduced by using plant-derived filler (B) and diacetyl monodecanoyl glyceride (D), thus achieving the intended objective.

[0007] However, the gist of the present invention is as follows: [1] to [7]. [1] A rubber composition containing the following (A) to (D). (A) Rubber-based polymer. (B) Plant-derived filler. (C) Carbon Black. (D) Diacetyl monodecanoyl glyceride. [2] Above (C) is DBP oil absorption 60~200cm 3 The rubber composition described in [1], wherein carbon black is present in 100g. [3] The rubber composition according to [1] or [2], wherein (A) is a rubber polymer having polar groups. [4] The rubber composition according to any one of [1] to [3], wherein (A) is at least one selected from the group consisting of acrylic rubber, acrylonitrile-butadiene rubber, chloroprene rubber, chlorosulfonated polyethylene rubber, epichlorohydrin homopolymer, epichlorohydrin-ethylene oxide binary copolymer, epichlorohydrin-allyl glycidyl ether binary copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer, and a blend polymer of acrylonitrile-butadiene rubber and polyvinyl chloride. [5] The rubber composition according to any one of [1] to [4], wherein (B) is at least one selected from the group consisting of cellulose, lignin, biomass plastic granules, granules obtained by crushing seed hulls, and granules obtained by crushing fruit kernels. [6] A rubber product obtained by crosslinking a rubber composition described in any of [1] to [5]. [7] A hose comprising one or more layers, wherein the layer comprises a crosslinked rubber composition according to any one of [1] to [5]. [Effects of the Invention]

[0008] From the above, the rubber composition of the present invention, as well as the rubber products and hoses obtained using it, can reduce the proportion of petroleum-derived raw materials without impairing the performance required of rubber products, such as elasticity. [Modes for carrying out the invention]

[0009] Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to these embodiments. In this invention, when "X~Y" (where X and Y are any numbers) is used, unless otherwise specified, it means "X or greater and Y or less," and also includes the meaning of "preferably greater than X" or "preferably less than Y." In addition, when expressed as "X or more" (X is any number) or "Y or less" (Y is any number), it also includes the intention of "preferably greater than X" or "preferably less than Y".

[0010] The rubber composition of the present invention (hereinafter referred to as "the present rubber composition") contains the following (A) to (D). (A) Rubber-based polymer. (B) Plant-derived filler. (C) Carbon black. (D) Diacetyl monodecanoyl glyceride.

[0011] The above components will be described in detail below.

[0012] [Rubber-based polymer (A)] The rubber-based polymer (A) used in the present rubber composition is not particularly limited, but a rubber-based polymer having a polar group is preferably used because of its good compatibility with the plant-derived filler.

[0013] Specific examples of the rubber-based polymer having a polar group as described above include acrylic rubber, acrylonitrile-butadiene rubber (NBR), chloroprene rubber, chlorosulfonated polyethylene rubber, epichlorohydrin rubber (epichlorohydrin homopolymer (CO), epichlorohydrin-ethylene oxide binary copolymer (ECO), epichlorohydrin-allyl glycidyl ether binary copolymer (GCO), epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer (GECO)), blend polymer of acrylonitrile-butadiene rubber and polyvinyl chloride (NBR-PVC), etc. These can be used alone or in combination of two or more. Among them, epichlorohydrin rubber and acrylonitrile-butadiene rubber are preferred because of their excellent compatibility with the plant-derived filler.

[0014] In addition, since the SP value of the rubber-based polymer is excellent in the dispersibility of the plant-derived filler (B) and carbon black (C), it is preferably 8.5 to 10.5, more preferably in the range of 9 to 10. Here, the SP value, also called the solubility parameter, is an index indicating the polarity of a substance and can be determined by the following formula (1).

[0015] [Number]

[0016] [Plant-derived filler (B)] Examples of the plant-derived filler (B) include granules of biomass plastics such as cellulose, lignin, and polylactic acid, granules obtained by pulverizing seed husks, granules obtained by pulverizing fruit cores, and the like. These can be used alone or in combination of two or more. Among them, cellulose and lignin are preferably used because of their excellent availability.

[0017] Examples of the plant materials that are the source of the plant-derived filler (B) include wood (coniferous trees such as red pine, black pine, Japanese larch, Siberian larch, Japanese red pine, Japanese larch, fir, hemlock, cedar, cypress, Japanese larch, Japanese elm, Japanese hemlock, Douglas fir, hemlock, white fir, spruce, balsam fir, cedar, pine, Merk's spruce, radiata pine, etc.) and broad-leaved trees such as beech, oak, Japanese walnut, oak, tab, Japanese oak, Japanese elm, hackberry, poplar, tamarack, drooping willow, eucalyptus, mangrove, lawan, acacia, etc.), bamboo, sugarcane, seed hair fibers (cotton fibers (cotton linter), kapok, etc.), bast fibers (hemp, mulberry, kozo, etc.), leaf fibers (Manila hemp, sisal hemp, New Zealand hemp, luobo hemp (ropuuma), etc.), fruit fibers (palm), rush, wheat straw, etc.

[0018] When the plant-derived filler (B) is cellulose fiber or cellulose nanofiber, its average fiber length is preferably 50 to 500 μm, more preferably 50 to 200 μm. Setting it in this way results in excellent reinforcing properties, dispersibility, and scalability. The average fiber length was calculated by measuring the fiber length of approximately 120 fibers using a transmission electron microscope (TEM) or scanning electron microscope (SEM) and then averaging the results.

[0019] In addition, commercially available plant-derived fillers (B) include, for example, "Fibra·Cel" (product name) from Celite Corporation, "Nanoforest" (product name) from Chuetsu Pulp Industry Co., Ltd., "BiNFi-s" (product name) from Sugino Machine Co., Ltd., "Selenpia" (product name) from Nippon Paper Industries Co., Ltd., "Celish" (product name) from Daicel Finechem Co., Ltd., "Fluorenecellulose" (product name) from Osaka Gas Chemical Co., Ltd., "KC Floc" (product name) from Nippon Paper Industries Co., Ltd., "Ceolus" (product name) from Asahi Kasei Corporation, "Tosco Hemp Cellulose Powder, Tosco Silk Powder, Bamboo Powder" (all product names) from Tosco Corporation, and "Cellulose Powder" (product name) from TDI Corporation.

[0020] Furthermore, the content of the plant-derived filler (B) in this rubber composition is preferably in the range of 10 to 80 parts by mass, more preferably 20 to 60 parts by mass, and even more preferably 20 to 40 parts by mass, per 100 parts by mass of the rubber polymer (A). This is because if the amount of plant-derived filler (B) is too small, it tends to adversely affect the reinforcing properties and vulcanization shrinkage properties, and if the amount of plant-derived filler (B) is too large, the elongation of the rubber tends to be poor.

[0021] [Carbon Black (C)] Examples of the carbon black (C) include grades such as SAF, ISAF, HAF, MAF, MAF-HS, FEF, GPF, SRF, SRF-HS, FT, and MT. These can be used individually or in combination of two or more. Among these, SRF-HS grade carbon black is preferred due to its excellent reinforcing properties.

[0022] Furthermore, the DBP oil absorption capacity of the carbon black (C) is 60-200 cm from the viewpoint of reinforcing properties. 3 It is preferably 100g, and more preferably 90-200cm 3 / 100g, more preferably 110-200cm 3 It is within the range of / 100g. Furthermore, the DBP oil absorption amount of the carbon black (C) is calculated by considering the structure of the carbon black as the amount of DBP (dibutyl phthalate) absorbed per 100g of carbon black (cm³). 3 The value is expressed as (per 100g). Furthermore, the DBP oil absorption amount is a value measured in accordance with JIS K 6217-4.

[0023] Furthermore, the carbon black (C) content in this rubber composition is preferably in the range of 5 to 80 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 15 to 40 parts by mass, per 100 parts by mass of the rubber polymer (A). In other words, if the amount of carbon black (C) is too small, the strength of the rubber composition tends to be inferior, and if the amount of carbon black (C) is too large, it is undesirable from the perspective of the present invention, which is to reduce the proportion of petroleum-derived raw materials.

[0024] [Diacetyl monodecanoyl glyceride (D)] The content of diacetyl monodecanoyl glyceride (D) in this rubber composition is preferably in the range of 5 to 60 parts by mass, more preferably 10 to 40 parts by mass, and even more preferably 15 to 30 parts by mass, per 100 parts by mass of the rubber polymer (A). In other words, if the amount of diacetyl monodecanoyl glyceride (D) is too small, the dispersion effect of the plant-derived filler (B) and carbon black (C) may not be sufficiently obtained, making it difficult to improve the decrease in the elastic properties of the rubber. If the amount of diacetyl monodecanoyl glyceride (D) is too large, it may adversely affect the processability of the rubber molding.

[0025] [Other materials] This rubber composition contains a rubber polymer (A), a plant-derived filler (B), carbon black (C), diacetyl monodecanoyl glyceride (D), as well as vulcanizing agents, vulcanizing aids, vulcanizing accelerators, processing aids, fillers (excluding plant-derived filler (B) and carbon black (C)), antioxidants, retarders, etc., as appropriate. Furthermore, when crosslinking with organic peroxides, co-crosslinking agents may be used in combination to improve crosslinking efficiency and enhance physical properties.

[0026] Examples of the vulcanizing agents include triazine compounds such as 1,3,5-triazine and 2,4,6-trimercapto-s-triazine; imidazole compounds such as 1-methylimidazole, 1,2-dimethylimidazole, 1-benzyl-2-methylimidazole, and 1-cyanoethyl-2-methylimidazole; and hexamethylenediamine, hexamethylenediamine carbamate, tetramethylenepentamine, hexamethylenediamine-cinnamaldehyde adduct, ammonium benzoate, hexamethylenediamine dibenzoate salt, 4,4'-methylenedianiline, 4,4'-oxyphenyldiphenylamine, m-phenylenediamine, p-phenylenediamine, and 4,4'-methylenebis(o-chloroaniline). These can be used alone or in combination of two or more. Furthermore, if the rubber polymer (A) is a diene rubber such as NBR, sulfur can be used as the vulcanizing agent, for example.

[0027] The content of the vulcanizing agent is usually set in the range of 0.5 to 3 parts by mass, preferably 1 to 2 parts by mass, per 100 parts by mass of the rubber polymer (A).

[0028] Vulcanization aid Examples of the aforementioned vulcanization aids include zinc oxide, activated zinc oxide, and magnesium oxide, which can be used alone or in combination of two or more.

[0029] The content of the vulcanization aid is usually set to a range of 0.5 to 5 parts by mass, preferably 2 to 4 parts by mass, per 100 parts by mass of the rubber polymer (A).

[0030] Vulcanization accelerator Examples of the aforementioned vulcanization accelerators include trimethylthiourea, stearyltrimethylammonium bromide, and di-o-tolylguanidine. These can be used individually or in combination of two or more.

[0031] The content of the vulcanization accelerator is usually set to a range of 0.5 to 5 parts by mass, preferably 1 to 3 parts by mass, per 100 parts by mass of the rubber polymer (A).

[0032] Processing aids Examples of the processing aids include stearic acid, n-octadecylamine, polyoxyethylene stearyl ether phosphate, and glycerin fatty acid esters. These can be used individually or in combination of two or more.

[0033] The content of the processing aid is usually set to a range of 0.5 to 5 parts by mass, preferably 1 to 3 parts by mass, per 100 parts by mass of the rubber polymer (A).

[0034] 《Filling material》 Other fillers besides the plant-derived filler (B) and carbon black (C) include, for example, silica, calcium carbonate, titanium dioxide, talc, clay, and glass balloons. These can be used individually or in combination of two or more.

[0035] The content of the filler is typically set to a range of 3 to 70 parts by mass, preferably 5 to 40 parts by mass, per 100 parts by mass of the rubber polymer (A).

[0036] Anti-aging agent Examples of the aforementioned antioxidants include 4,4'-(α,α-dimethylbenzyl)diphenylamine and nickel dibutyldithiocarbamate. These can be used alone or in combination of two or more.

[0037] The content of the anti-aging agent is usually set to a range of 0.5 to 5 parts by mass, preferably 1 to 2 parts by mass, per 100 parts by mass of the rubber polymer (A).

[0038] Delaying agent Examples of the aforementioned retarders include phthalic anhydride, benzoic acid, salicylic acid, N-nitrosodiphenylamine, N,N',N''-tris(isopropylthio)-N,N',N''-triphenylphosphoric triamide, N-cyclohexylthiophthalimide, and N-(trichloromethylthio)benzenesulfonamide. These can be used individually or in combination of two or more.

[0039] The content of the retarder is usually set in the range of 0.1 to 3 parts by mass, preferably in the range of 0.5 to 1.5 parts by mass, per 100 parts by mass of the rubber polymer (A).

[0040] 《Organic peroxide》 Examples of the aforementioned organic peroxides include 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)cyclododecane, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(t-butylperoxy)octane, n-butyl-4,4-bis(t-butylperoxy)butane, n-butyl-4,4-bis( Peroxyketals such as t-butylperoxy)valerate, dialkylperoxides such as di-t-butylperoxide, dicumylperoxide, t-butylcumylperoxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, α,α'-bis(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexine-3, acetylperoxide, isobutylperoxide Diacyl peroxides such as oxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, m-trioyl peroxide, and t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxylaurate, t-butyl peroxybenzoate, and di-t-butyl peroxy Examples include peroxyesters such as xyisophthalate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butylperoxymaleic acid, t-butylperoxyisopropyl carbonate, and cumylperoxyoctate, as well as hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, and 1,1,3,3-tetramethylbutylperoxide. These can be used individually or in combination of two or more.

[0041] The content of the organic peroxide is usually set in the range of 0.1 to 5 parts by mass, preferably in the range of 0.3 to 2 parts by mass, per 100 parts by mass of the rubber polymer (A).

[0042] Co-crosslinking agent Examples of the aforementioned cocrosslinking agents include sulfur-containing compounds, polyfunctional monomers, maleimide compounds, and quinone compounds. These can be used individually or in combination of two or more.

[0043] Examples of the sulfur-containing compounds include sulfur, dipentamethylenethuram tetrasulfide, and mercaptobenzothiazole. Examples of the polyfunctional monomers include divinylbenzene, ethylene glycol dimethacrylate, diallyl phthalate, trimethylolpropane trimethacrylate, triallyl cyanurate, triallyl isocyanurate (TAIC), triallyl trimellitate, and triallyl tricyanurate. Examples of the maleimide compounds include N,N'-m-phenylenebismaleimide and toluenebismaleimide. Examples of the quinone compounds include quinone dioxime and dibenzoyl-p-quinone dioxime.

[0044] The content of the co-crosslinking agent is usually set in the range of 0.1 to 5 parts by mass, preferably in the range of 0.3 to 2 parts by mass, per 100 parts by mass of the rubber polymer (A).

[0045] This rubber composition can be prepared, for example, by blending a rubber polymer (A), a plant-derived filler (B), carbon black (C), and diacetyl monodecanoyl glyceride (D), and further blending other components as needed, and then kneading them using a kneader such as a roll, kneader, or Banbury mixer. Then, by crosslinking the rubber composition into a predetermined shape using a mold or the like as needed, the desired rubber product can be manufactured. The rubber product of the present invention obtained in this way (hereinafter referred to as "this rubber product") can reduce the proportion of petroleum-derived raw materials without impairing the performance required of rubber products, such as stretchability. Examples of these rubber products include hoses, gaskets, oil seals, rolls for office automation equipment, and vibration-damping rubber.

[0046] Here, as an example of a manufacturing method for this rubber product, the manufacturing method for a hose is shown below. Specifically, first, after preparing the rubber composition as described above, the rubber composition is extruded into a tubular (cylindrical) shape to form an uncrosslinked rubber layer. When a multilayer hose is to be formed, layers made of various rubbers and resins are formed on the outer circumference of the rubber layer (innermost layer) by extrusion molding or the like. When forming a reinforcing yarn layer, a reinforcing yarn layer is formed on the outer circumference of the rubber layer (innermost layer) by braiding or the like with a predetermined number of draws and counts of threads. A mandrel is inserted into the uncrosslinked hose structure obtained in this way. A release agent such as silicone oil may be applied to the surface of the mandrel as needed. Alternatively, instead of inserting the mandrel into the uncrosslinked hose structure (uncrosslinked rubber hose) as described above, the rubber composition may be directly extruded onto the mandrel. The uncrosslinked rubber hose extruded onto the mandrel in this way is then crosslinked with pressurized steam, the mandrel is removed, and secondary crosslinking is performed in an oven as needed to produce the desired hose.

[0047] The hose of the present invention obtained in this manner (hereinafter referred to as "this hose") may have a single-layer structure or a multilayer structure in which two or more layers are laminated.

[0048] In this hose, the overall thickness is preferably 0.25 to 20 mm, and more preferably 0.5 to 10 mm. The inner diameter of the hose is preferably 2 to 100 mm, and more preferably 5 to 70 mm.

[0049] This hose is not particularly limited, but is preferably used in applications where it is required to reduce the proportion of petroleum-derived raw materials without impairing properties such as elongation. For example, it can be used as a fuel hose, air hose, or oil hose for automobiles. [Examples]

[0050] Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples.

[0051] First, prior to the examples and comparative examples, the following materials were prepared.

[0052] [ECO] Epichlorohydrin rubber, HYDRIN T3105B, manufactured by Zeon Corporation.

[0053] [NBR] Acrylonitrile-butadiene rubber, Nipol DN101, manufactured by Nippon Zeon Corporation.

[0054] [Cellulose fiber] KC Flock W-400G, manufactured by Nippon Paper Industries Co., Ltd.

[0055] [Carbon Black (i)] SRF-HS grade carbon black (DBP oil absorption capacity 125cm³) 3 (100g) (SPHERON 5200, manufactured by Cabot Japan Co., Ltd.)

[0056] [Carbon Black (ii)] SRF grade carbon black (DBP oil absorption capacity 68cm) 3 (100g) (Seast S, manufactured by Tokai Carbon Co., Ltd.)

[0057] [Carbon Black (iii)] MAF-HS grade carbon black (DBP oil absorption capacity 158cm³) 3 (100g) (Seas G-116HM, manufactured by Tokai Carbon Co., Ltd.)

[0058] [Plasticizer (i)] Diacetyl monodecanoyl glyceride (BIOCIZER, manufactured by Riken Vitamin Co., Ltd.)

[0059] [Plasticizers (ii)] Polyether ester plasticizer (ADEKA RS966, manufactured by ADEKA Corporation)

[0060] [Example 1] A rubber composition was prepared by mixing 100 parts by mass of ECO, 30 parts by mass of cellulose fiber, 15 parts by mass of carbon black (i), 15 parts by mass of plasticizer (i), 2 parts by mass of stearic acid (Bead Stearic Acid Sakura, manufactured by NOF Corporation), 3 parts by mass of magnesium oxide (Kyowa Mag 150, manufactured by Kyowa Chemical Industry Co., Ltd.), 1 part by mass of antioxidant (Nocrack NBC, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), 1.5 parts by mass of processing aid (Rikemar XO-100, manufactured by Riken Vitamin Co., Ltd.), 1 part by mass of retarder (Retarder CTP, manufactured by Toray Industries, Inc.), and 1.5 parts by mass of 2,4,6-trimercapto-s-triazine (ZISNET F, manufactured by Sankyo Chemical Co., Ltd.), kneading it using a 5L kneader, then transferring it to an open roll and continuing kneading.

[0061] [Examples 2, 3, Comparative Examples 1-3] The rubber composition was prepared in accordance with Example 1, except that the types and amounts of each material shown in Table 1 below were changed as shown in the same table.

[0062] [Example 4] A rubber composition was prepared by mixing 100 parts by mass of NBR, 30 parts by mass of cellulose fiber, 15 parts by mass of carbon black (i), 15 parts by mass of plasticizer (i), 2 parts by mass of stearic acid (bead stearic acid sakura, manufactured by NOF Corporation), 3 parts by mass of magnesium oxide (Kyowa Mag 150, manufactured by Kyowa Chemical Industry Co., Ltd.), 1 part by mass of antioxidant (Nocrack NBC, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), 1.5 parts by mass of processing aid (Rikemar XO-100, manufactured by Riken Vitamin Co., Ltd.), 1 part by mass of retarder (retarder CTP, manufactured by Toray Industries, Inc.), and 1 part by mass of sulfur (manufactured by Tsurumi Chemical Industry Co., Ltd.), kneading the mixture using a 5L kneader, then transferring it to an open roll and continuing the kneading process.

[0063] The rubber compositions of the examples and comparative examples obtained in this manner were evaluated for each property according to the following criteria. These results are also shown in Table 1 below.

[0064] <<Elongation / Strength Properties>> The aforementioned rubber composition was press-molded using a vulcanizing press to produce a 2 mm thick rubber sheet for tensile property measurement, thereby creating a vulcanized rubber sheet. Next, the tensile strength TS (MPa) and elongation EB (%) of the sample obtained from the vulcanized rubber sheet were measured according to JIS K 6251-2017 (Vulcanized rubber and thermoplastic rubber - Method for determining tensile properties). Then, the tensile strength and elongation were evaluated according to the following criteria. ◎: Tensile strength TS is 9.0 MPa or higher and elongation EB is 350% or higher. ○: Tensile strength TS is 5.0 MPa or higher and elongation EB is 200% or higher. ×: Tensile strength TS is less than 5.0 MPa and / or elongation EB is less than 200%

[0065] Carbon neutrality The ratio of biomass-derived materials used in the rubber composition to the entire rubber composition was calculated, and the carbon neutrality was evaluated according to the following criteria. ◎: Biomass-derived material ratio is 50% or more by mass. ○: The proportion of biomass-derived materials is 20% by mass or more and less than 50% by mass. ×: The proportion of biomass-derived materials is less than 20% by mass.

[0066] <<Vulcanization shrinkage>> The rubber composition was hollow extruded into a tubular (cylindrical) shape with an inner diameter of 30 mm and a wall thickness of 4 mm, and then cut to a length of 300 mm. The unvulcanized rubber hose thus obtained was pressure vulcanized with steam at 160°C for 20 minutes to obtain a rubber hose. The vulcanization shrinkage rate of the rubber hose was determined by the following formula and evaluated according to the following criteria. Vulcanization shrinkage rate (%) = [(Length of unvulcanized rubber hose - Length of vulcanized rubber hose) / Length of unvulcanized rubber hose] × 100 ◎: Shrinkage rate less than 2% ○: Shrinkage rate of 2% or more but less than 8% ×: Shrinkage rate of 8% or more

[0067] [Table 1]

[0068] As shown in Table 1 above, all of the rubber compositions in the examples exhibited excellent elongation / strength properties, satisfies carbon neutrality requirements, and also showed excellent vulcanization shrinkage properties.

[0069] In contrast, the rubber composition of Comparative Example 1 did not contain cellulose fibers and resulted in inferior carbon neutrality and vulcanization shrinkage. The rubber composition of Comparative Example 2, like the example, used cellulose fibers and carbon black in combination, but did not contain diacetylmonodecanoyl glyceride and resulted in inferior elongation / strength properties. The rubber composition of Comparative Example 3, like the example, also used cellulose fibers and carbon black in combination, but used a polyether ester-based plasticizer instead of diacetylmonodecanoyl glyceride, and no improvement in elongation / strength properties was observed. [Industrial applicability]

[0070] This rubber composition is used as a material for various rubber products such as hoses, gaskets, oil seals, rolls for office automation equipment, and vibration-damping rubber. Preferably, it is used as a forming material for hoses such as fuel hoses, air hoses, and oil hoses for automobiles. These hoses are then preferably used in transport equipment such as automobiles, tractors, tillers, and ships.

Claims

1. A rubber composition containing the following (A) to (D). (A) Rubber-based polymer. (B) At least one plant-derived filler selected from the group consisting of cellulose and lignin. (C) Carbon Black. (D) Diacetyl monodecanoyl glyceride.

2. The above (C) has a DBP oil absorption of 60 to 200 cm. 3 The rubber composition according to claim 1, wherein the carbon black is 100g.

3. The rubber composition according to claim 1 or 2, wherein (A) is a rubber polymer having polar groups.

4. The rubber composition according to any one of claims 1 to 3, wherein (A) is at least one selected from the group consisting of acrylic rubber, acrylonitrile-butadiene rubber, chloroprene rubber, chlorosulfonated polyethylene rubber, epichlorohydrin homopolymer, epichlorohydrin-ethylene oxide binary copolymer, epichlorohydrin-allyl glycidyl ether binary copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer, and a blend polymer of acrylonitrile-butadiene rubber and polyvinyl chloride.

5. A rubber product comprising a crosslinked rubber composition according to any one of claims 1 to 4.

6. A hose comprising one or more layers, wherein the hose comprises a layer made of a crosslinked rubber composition according to any one of claims 1 to 4.

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