V-belt

Abstract

The objective of this invention is to provide a novel V-belt with excellent durability. As a solution, a V-belt is provided, comprising: an adhesive rubber layer with a core wire embedded therein extending along the belt length direction; and a compression rubber layer laminated on the inner periphery of the adhesive rubber layer. Regarding the rubber composition forming the compression rubber layer, when the value of the storage modulus (E') of the rubber composition test piece taken in the belt width direction, based on JIS K6394, at a frequency of 10 Hz and a test temperature of 25 °C, and measured by a tensile method, is set as X (MPa), and the value of the elongation of the rubber composition test piece taken in the belt length direction is set as Y (%), the following (1) and (2) are simultaneously satisfied: (1) X > 800 (2) Y > -42.05·ln(X) + 340.

Description

Technical Field

[0001] This invention relates to a V-shaped belt. Background Technology

[0002] Drive belts are widely used in general industrial machinery, as well as in transportation equipment such as four-wheeled vehicles and two-wheeled vehicles. Durability is strongly required for drive belts to ensure long-term use and reduce replacement frequency. For example, Patent Document 1 discloses a durable drive belt using ethylene propylene diene monomer (EPDM) rubber, which exhibits excellent weather resistance and cold resistance.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2002-81506 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] The objective of this invention is to provide a novel V-belt with excellent durability.

[0008] Technical means to solve the problem

[0009] The structure of the present invention used to solve the aforementioned problem is as follows.

[0010] 1. A V-shaped belt comprising: an attached rubber layer, and embedded core wires extending along the belt length direction; and

[0011] A compression rubber layer is stacked on the inner periphery of the adhesive rubber layer.

[0012] Regarding the rubber composition forming the compressed rubber layer, when the value of the storage elastic modulus (E') of the rubber composition test piece taken in the width direction based on Japanese Industrial Standards (JIS) K6394, at a frequency of 10 Hz and a test temperature of 25 °C, and measured by a tensile method with a dynamic strain of 0.1% strain is set as X (MPa), and the value of the elongation of the rubber composition test piece taken in the length direction is set as Y (%), the following (1) and (2) are satisfied simultaneously.

[0013] (1) X>800

[0014] (2) Y>-42.05·ln(X)+340

[0015] 2. The V-belt according to 1, wherein the rubber composition comprises bonded polyaramid short fibers.

[0016] 3. The V-belt according to 1 or 2, wherein the rubber composition comprises an ethylene-α-olefin elastomer as a rubber component.

[0017] 4. The V-belt according to any one of 1 to 3, wherein the rubber composition comprises an unsaturated carboxylic acid metal salt.

[0018] 5. The V-belt according to any one of 1 to 4, wherein it is a toothed V-belt.

[0019] The effects of the invention

[0020] The V-belt of this invention exhibits excellent durability. It demonstrates excellent durability in both low-speed and high-speed power transmission, and reduces the frequency of replacement. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a double-toothed V-belt according to one embodiment of the present invention.

[0022] Figure 2 This is a graph showing the relationship between the storage elastic modulus and elongation of the double-toothed V-belts obtained in the embodiments and comparative examples.

[0023] Explanation of icon numbers

[0024] 1 Double-tooth V-belt

[0025] 10 with main body

[0026] 11 Next, the rubber layer

[0027] 111 core wire

[0028] 12 Compressed rubber layers

[0029] 12a Lower tooth

[0030] 121 Bottom Reinforcement Fabric

[0031] 13. Elongated rubber layer

[0032] 13a Upper teeth Detailed Implementation

[0033] The V-shaped belt of the present invention comprises: an adhesive rubber layer with embedded core wires extending along the belt length direction; and a compression rubber layer stacked on the inner periphery of the adhesive rubber layer.

[0034] Regarding the rubber composition forming the compression rubber layer, when the value of the storage modulus (E') of the rubber composition test piece taken in the belt width direction, based on JIS K6394, at a frequency of 10 Hz and a test temperature of 25 °C, and measured by tensile method, with a dynamic strain of 0.1% strain, is set as X (MPa), and the value of the elongation of the rubber composition test piece taken in the belt length direction is set as Y (%), the following (1) and (2) are simultaneously satisfied. In addition, "ln" is the natural logarithm.

[0035] (1) X>800

[0036] (2) Y>-42.05·ln(X)+340

[0037] Figure 1 A schematic diagram of a double-toothed V-belt as an embodiment of the present invention is shown.

[0038] One embodiment of the double-toothed V-belt 1 has a belt body 10 integrally formed by stacking an adhesive rubber layer 11, a compression rubber layer 12, and an elongation rubber layer 13. The adhesive rubber layer 11 has a core wire 111 embedded therein, extending approximately along the belt length direction. The compression rubber layer 12 is stacked on the inner circumferential side of the adhesive rubber layer 11, and the elongation rubber layer 13 is stacked on the outer circumferential side of the adhesive rubber layer 11. Lower teeth 12a are formed on the inner circumferential surface of the compression rubber layer 12, and upper teeth 13a are formed on the outer circumferential surface of the elongation rubber layer 13. A bottom reinforcing fabric 121 is embedded in the compression rubber layer 12 to cover its inner circumferential surface.

[0039] Furthermore, the V-belt of the present invention is not limited to a double-toothed V-belt, but can be configured as a toothed V-belt, a cut-edge V-belt, a fabric-covered V-belt, a V-ribbed belt, etc.

[0040] • Compression rubber layer

[0041] The compression rubber layer 12 has an isosceles trapezoidal shape in the width direction, with the upper base longer than the lower base. Along the length direction of the belt, there are lower teeth 12a with a length direction cross-section that is approximately sinusoidal. The compression rubber layer 12 has a bottom reinforcing cloth 121 embedded in it to cover the inner circumferential surface of the belt, but the bottom reinforcing cloth may not be provided.

[0042] The compression rubber layer 12 is formed of a rubber composition. Examples of rubber components included in the rubber composition include: ethylene-α-olefin elastomers, chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), hydrogenated acrylonitrile rubber (H-NBR), natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), nitrile rubber (NBR), etc., and one or more of these can be mixed. Examples of ethylene-α-olefin elastomers include: ethylene propylene diene rubber (ethylene propylene diene monomer (EPDM)), ethylene propylene rubber (ethylene propylene monomer (EPM)), ethylene butene rubber (ethylene butene monomer (EBM)), ethylene octene rubber (ethylene octene monomer (EOM)), etc. Among these, it is preferable that the rubber composition contains ethylene-α-olefin elastomers (EPDM, EPM, etc.) and chloroprene rubber (CR), more preferably EPDM. The content of ethylene-α-olefin elastomers in the rubber composition is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass. In addition to ethylene-α-olefin elastomers, the rubber composition may also contain chloroprene rubber (CR), hydrogenated acrylonitrile rubber (H-NBR), natural rubber (NR), etc.

[0043] The EPDM preferably contains 40% by mass or more and 60% by mass or less, more preferably 45% by mass or more and 55% by mass or less, and even more preferably 50% by mass or more and 53% by mass or less. The diene content of the EPDM is preferably 4% by mass or more and 14% by mass or less, more preferably 6% by mass or more and 12% by mass or less, and even more preferably 7% by mass or more and 8% by mass or less. Dicyclopentadiene (DCPD), 5-ethylidene-2-norbornene (ENB), 1,4-hexadiene (1,4-HD), etc., can be used as diene components, among which ENB is preferred. EPDM may also be a mixture of one or more different compositions.

[0044] When EPDM has a Mooney viscosity of 40 or less at 125°C, it can uniformly mix the uncrosslinked rubber composition. Therefore, it is preferable that the Mooney viscosity is 35 or less, and even more preferably 30 or less.

[0045] The crosslinking agent used to crosslink the rubber components can be an organic peroxide, sulfur, polyamine, oxime, nitrosyl, or more than one or two of these. Alternatively, the rubber composition can be crosslinked using an electron beam or similar method. Of these, organic peroxides are preferred in terms of abrasion resistance.

[0046] As organic peroxides, substances capable of crosslinking rubber components can be used without particular limitation, such as: di-tert-butyl peroxide, tert-butylcumyl peroxide, dicumyl peroxide, α,α'-bis(tert-butylperoxy)-p-diisopropylbenzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyldi(tert-butyl)hexyne, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butyl isopropyl carbonate peroxide, 1,1-bis(tert-butylperoxy)-3,5,5-trimethylcyclohexane, etc. One or more of these organic peroxides can be used. The content of the organic peroxide is generally, for example, preferably 0.5 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass of the rubber component, more preferably 1 part by mass or more and 7 parts by mass or less, and even more preferably 2.5 parts by mass or more and 4 parts by mass or less.

[0047] The rubber composition preferably contains a co-crosslinking agent. Examples of co-crosslinking agents include unsaturated carboxylic acid metal salts, N,N'-m-phenylenebismaleimide, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, triallyl isocyanurate, etc., and one or more of these may be used. An unsaturated carboxylic acid metal salt is a salt of an unsaturated carboxylic acid having at least one carboxyl group and a metal. Examples of unsaturated carboxylic acids include monocarboxylic acids such as acrylic acid and methacrylic acid; and dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid. Examples of metals include zinc, magnesium, calcium, barium, titanium, chromium, iron, cobalt, nickel, aluminum, tin, lead, etc. The molar ratio of the unsaturated carboxylic acid to the metal (moles of unsaturated carboxylic acid / moles of metal) is preferably 2 mol / 1 mol. Examples of unsaturated carboxylic acid metal salts include zinc acrylate, zinc dimethacrylate, and magnesium dimethacrylate.

[0048] Among these, zinc dimethacrylate or N,N'-m-phenylenebismaleimide is preferably included as a co-crosslinking agent. When zinc dimethacrylate is included, its content relative to 100 parts by weight of the rubber component is preferably 5 parts by weight or more and 60 parts by weight or less, more preferably 10 parts by weight or more and 50 parts by weight or less, and even more preferably 25 parts by weight or more and 45 parts by weight or less. When N,N'-m-phenylenebismaleimide is included, its content relative to 100 parts by weight of the rubber component is preferably 1 part by weight or more and 20 parts by weight or less, more preferably 2 parts by weight or more and 10 parts by weight or less, and even more preferably 3 parts by weight or more and 7 parts by weight or less.

[0049] The rubber composition preferably includes short fibers. As short fibers, one or more of the following can be used: para-polyaramid short fibers, meta-polyaramid short fibers, poly(p-phenylenebenzobisoxazole) short fibers, nylon 6 short fibers, nylon 6,6 short fibers, nylon 4,6 short fibers, polyethylene terephthalate short fibers, polyethylene naphthalate short fibers, cellulose fibers, pulp, or cotton, etc. The short fibers may also be treated with resorcinol formalin latex (RFL) by impregnation in a resorcinol-formaldehyde-latex aqueous solution followed by heating. The total amount of short fibers relative to 100 parts by weight of the rubber component is preferably 10 parts by weight or more and 35 parts by weight or less.

[0050] The fiber length of the short fiber is preferably 1 mm or more and 10 mm or less, more preferably 2 mm or more and 3.5 mm or less.

[0051] The fiber diameter of the short fibers is preferably 5 μm or more and 50 μm or less, more preferably 7 μm or more and 20 μm or less, and even more preferably 11 μm or more and 13 μm or less.

[0052] Short fibers are aggregates of filaments. The fineness of the filaments constituting short fibers is preferably 1 dtex or more and 5 dtex or less, more preferably 1.4 dtex or more and 1.6 dtex or less.

[0053] The preferred short fiber is one containing polyaramid short fibers, more preferably one containing bonded polyaramid short fibers. The polyaramid short fibers are preferably para-based. The bond treatment can be any one or more of the following: RFL treatment involving impregnation in a resorcinol-formaldehyde-latex aqueous solution followed by heating; bond treatment involving impregnation in a rubber slurry followed by drying; or bond treatment involving impregnation in an adhesive solution containing an epoxy resin or polyisocyanate resin followed by heating. Two or more polyaramid short fibers can be used, varying in material, fiber length, fiber diameter, filament fineness, and the presence or absence of bond treatment. When bonded polyaramid short fibers are included, the amount of bonded polyaramid short fibers relative to the overall rubber composition is preferably 10 parts by weight or more and 35 parts by weight or less, more preferably 15 parts by weight or more and 33 parts by weight or less, and even more preferably 20 parts by weight or more and 30 parts by weight or less, relative to 100 parts by weight of the rubber component.

[0054] In addition to the above, the rubber composition may also contain additives such as reinforcing agents, processing aids, vulcanization accelerators, vulcanization accelerators, anti-aging agents, processing oils, anti-scorching agents, ultraviolet absorbers, light stabilizers, softeners, foaming agents, foaming aids, lubricants, flame retardants, antistatic agents, colorants, and plasticizers. Furthermore, in this invention, these additives are arbitrary and may not be included. However, in this invention, "including" means formulated at a concentration sufficient to exert the effects of the agent; "not including" does not preclude formulation at a concentration that does not exert the effects of the agent.

[0055] As a reinforcing material, one or more inorganic particles selected from silica, carbon black, titanium dioxide, alumina, calcium carbonate, magnesium carbonate, zinc carbonate, barium sulfate, diatomaceous earth, clay, talc, and zinc oxide can be incorporated. The amount of inorganic particles incorporated is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, relative to 100 parts by mass of the rubber component. Furthermore, the upper limit of the incorporated amount is preferably 100 parts by mass or less, more preferably 90 parts by mass or less.

[0056] As an inorganic particle, carbon black is preferred in terms of imparting and enhancing conductivity, and preventing ultraviolet degradation. There are no particular restrictions on the carbon black used in the blend. Examples include: channel black; super abrasion furnace black (SAF), intermediate super abrasion furnace black (ISAF), N-339, high abrasion furnace black (HAF), N-351, medium abrasion furnace black (MAF), fast extruding furnace black (FEF), semi-reinforcing furnace black (SRF), general purpose furnace black (GPF), extra conductive furnace black (ECF), N-234, etc.; fine thermal black (FT), medium thermal black (MT), etc.; acetylene black, Ketjen black EC300J, Ketjen black EC600JD, etc. One or more types can be blended. Among these, ISAF, HAF, and FEF are preferred.

[0057] Examples of processing aids include stearic acid, polyethylene wax, and metal salts of fatty acids. One or more of these processing aids may be used. The content of the processing aid, for example, is 0.5 parts by mass and 2 parts by mass or less per 100 parts by mass of the rubber component.

[0058] Examples of vulcanization accelerators include: thiuram-based substances (e.g., tetraethylthiuram disulfide (TETD), tetramethylthiuram disulfide (TT), dipentamethylene thiuram tetrasulfide (TRA), etc.), thiazole-based substances (e.g., 2-mercaptobenzothiazole (MBT), dibenzothiazol disulfide (MBTS), etc.), sulfenamide-based substances (e.g., N-cyclohexyl-2-benzothiazole sulfenamide (CZ), etc.), and dithiocarbamate-based substances (e.g., BZ-P, etc.). One or more of these substances can be used as vulcanization accelerators. The content of vulcanization accelerator is, for example, more than 2 parts by mass and less than 5 parts by mass relative to 100 parts by mass of rubber component.

[0059] Examples of vulcanization accelerators include metal oxides such as zinc oxide (zinc white) or magnesium oxide, metal carbonates, fatty acids and their derivatives. One or more of these can be used as vulcanization accelerators. The content of the vulcanization accelerator relative to 100 parts by weight of the rubber component is 3 parts by weight or more and 7 parts by weight or less.

[0060] Examples of anti-aging agents include amine-ketone based anti-aging agents, diamine based anti-aging agents, and phenolic based anti-aging agents. One or more of these can be used as the anti-aging agent. The content of the anti-aging agent is 0.1 parts by weight or more and 5 parts by weight or less per 100 parts by weight of the rubber component.

[0061] Examples of processing oils include paraffinic oils, naphthenic oils, ester oils, and aromatic oils. One or more of these can be used as the processing oil. The content of the processing oil is preferably 0.1 to 40 parts by weight, more preferably 0.1 to 20 parts by weight, relative to 100 parts by weight of the rubber component.

[0062] When the value of the storage elastic modulus (E') of the rubber composition test piece taken in the width direction of the belt, based on JIS K6394, at a frequency of 10 Hz and a test temperature of 25 °C and measured by tensile method, is set as X (MPa), and the value of the elongation of the rubber composition test piece taken in the length direction of the belt is set as Y (%), the rubber composition forming the compression rubber layer of the present invention simultaneously satisfies the following (1) and (2).

[0063] (1) X>800

[0064] (2) Y>-42.05·ln(X)+340

[0065] Furthermore, the storage modulus of elasticity is a value determined by tensile method based on JIS K6394:2007, with the strain at 1.3 times the load at 1% load strain as the average strain, and the strain amplitude at 0.1%, frequency at 10 Hz, and test temperature at 25°C. Additionally, the elongation is a value determined based on JIS K6251:2017.

[0066] (1) In particular, from the viewpoint of obtaining excellent durability when driving at low speed with a small gear ratio, the value of the storage elastic modulus (E') X (MPa) is preferably 850 MPa or more, more preferably 950 MPa or more, and even more preferably 1000 MPa or more.

[0067] (2) In particular, from the viewpoint of obtaining excellent durability when driving at high speed with a large gear ratio, the elongation value Y (%) of the rubber composition test piece is preferably Y > -42.05·ln(X) + 342 or more, more preferably Y > -42.05·ln(X) + 345 or more, and even more preferably Y > -42.05·ln(X) + 350 or more.

[0068] The bottom reinforcing fabric 121 may include, for example, woven fabrics, braided fabrics, or non-woven fabrics formed from synthetic or natural fibers. Alternatively, a back reinforcing fabric may be provided on the outer peripheral surface of the elongated rubber layer 13. To improve adhesion to the rubber composition, these reinforcing fabrics may undergo one or more of the following treatments: RFL treatment involving impregnation in a resorcinol-formaldehyde-latex aqueous solution followed by heating; bonding treatment involving impregnation in a rubber slurry followed by drying; and bonding treatment involving impregnation in an adhesive solution containing a solution such as epoxy resin or polyisocyanate resin followed by heating.

[0069] • Next, the rubber layer, then the elongated rubber layer

[0070] Next, both the rubber layer 11 and the elongated rubber layer 13 are formed from a rubber composition. The rubber compositions forming the rubber layer 11 and the elongated rubber layer 13 may be the same as those used to form the compression rubber layer 12, or they may be different.

[0071] Next, a core wire 111 extending along the length of the strip is embedded in the rubber layer 11.

[0072] The core wire 111 comprises twisted yarns or ribbons such as polyethylene terephthalate (PET) fibers, polyethylene naphthalate (PEN) fibers, para-aramid fibers, and vinylon fibers. To improve adhesion to the rubber composition forming the adhesive rubber layer 11, the core wire 111 may undergo one or more of the following treatments: RFL treatment (immersion in a resorcinol-formaldehyde-latex aqueous solution followed by heating); bonding treatment (immersion in a rubber slurry followed by drying); and bonding treatment (immersion in an adhesive solution containing epoxy resin or polyisocyanate resin followed by heating).

[0073] Manufacturing method

[0074] The manufacturing method of the V-belt of the present invention is not particularly limited and can be carried out by existing methods, such as the following methods.

[0075] A rubber composition for compressing rubber layers is obtained by mixing various materials and forming it into a sheet, thereby obtaining an uncrosslinked rubber sheet.

[0076] Uncrosslinked rubber sheet is wound around the outer circumferential surface of a cylindrical mold, which includes circumferentially continuous tooth-forming grooves. After release paper is wound around its outer circumference, a rubber sleeve is placed over it, and the mold is placed in a vulcanizing tank and sealed. Simultaneously, high-temperature and high-pressure steam is filled into the vulcanizing tank, and this state is maintained for a specified time. At this time, the uncrosslinked rubber sheet flows and is pressed into the tooth-forming grooves, while approximately half of the crosslinking occurs, thereby forming a cylindrical toothed composite with toothed inner circumference. When the rubber sheet contains short fibers, it is preferable to arrange them so that their texture direction is axially aligned with the cylindrical shape, i.e., in the width direction.

[0077] After removing the rubber sleeve and allowing it to cool, the outer periphery of the lower toothed composite is ground to adjust the thickness.

[0078] Subsequently, an uncrosslinked rubber sheet for forming an adhesive rubber layer is wound around the outer peripheral surface of the lower tooth composite, a core wire is spirally wound around it, and then an uncrosslinked rubber sheet for forming an adhesive rubber layer and an uncrosslinked rubber sheet for forming an elongated rubber layer are sequentially wound around it, thereby forming an uncrosslinked blank.

[0079] A rubber sleeve comprising an upper tooth forming groove continuously arranged circumferentially on the inner circumferential surface is covered on the uncrosslinked slab blank. Then, a second rubber sleeve is covered on the uncrosslinked slab blank, and the slab blank is placed in a vulcanizing tank and sealed. Simultaneously, high-temperature and high-pressure steam is filled into the vulcanizing tank, and this state is maintained for a specified time. At this time, the lower tooth composite undergoes formal crosslinking, simultaneously bonding the rubber layer to the core wire. Additionally, uncrosslinked rubber sheets used to form the elongated rubber layer flow and are pressed into the upper tooth forming groove, where they undergo crosslinking, thereby forming a cylindrical strip slab blank.

[0080] After the steam is discharged from the vulcanizing tank, the seal is released, the rubber sleeve is removed and cooled, and the slab is demolded from the mold.

[0081] After the strip blank is cut to a specified width, it is cut in a way that forms a V-shaped side to obtain a double-tooth V-shaped strip.

[0082] Example

[0083] The present invention will be described in more detail below with reference to specific embodiments, but the present invention is not limited to these embodiments.

[0084] A compression rubber layer is formed according to the formulation shown in Table 1 below. By using the method described, a double-toothed V-belt with a circumference of 1200 mm, a maximum width of 33 mm, and a maximum thickness of 16 mm is obtained. Furthermore, the elongated rubber layer and the adhesive rubber layer of the double-toothed V-belt are formed from a cross-linked rubber composition with EPDM as the rubber component. The core yarn is composed of twisted para-aramid fibers. The bottom reinforcing fabric is composed of woven PET fibers.

[0085] Regarding the rubber composition that forms the compression rubber layer, the short fibers and agents other than the crosslinking agent are mixed and cooled using a Bambury mixer, and then the short fibers and crosslinking agent are added for further mixing.

[0086] [Table 1]

[0087]

[0088] EPDM1: T7241, manufactured by JSR, ethylene content: 52% by mass, ENB content: 7.7% by mass, ML (125℃) 27

[0089] EPDM2: X-4010M, manufactured by Mitsui Chemicals, ethylene content: 54% by mass, ENB content: 7.6% by mass, 8 ml (100°C)

[0090] EPDM3: EP123, manufactured by JSR Corporation, ethylene content: 58% by mass, ENB content: 4.5% by mass, ML (125℃) 19.5

[0091] EPDM4: NORDEL IP 4725P, manufactured by Dow Chemical Company, ethylene content: 70% by mass, ENB content: 4.9% by mass, ML (125℃) 25

[0092] EPDM5: NORDEL IP 4770P, manufactured by Dow, ethylene content: 70% by mass, ENB content: 4.9% by mass, ML (125℃) 70

[0093] Furthermore, the ML (125°C) of the mixtures of multiple EPDMs used in Examples 2 and 5, i.e., the rubber compositions, were 20.7 and 35.2, respectively.

[0094] Zinc oxide: Zinc oxide is manufactured by Sakai Chemical Co., Ltd.

[0095] Stearic acid: Stearic acid S50 manufactured by Shin Nippon Rikka Co., Ltd.

[0096] Lubricant: Struktol WB16, manufactured by S&S Japan.

[0097] Anti-aging agent: Nocrac MB, manufactured by Ouchi New Chemical Industry Co., Ltd.

[0098] ISAF carbon black: Seast 6 manufactured by Tokai Carbon Co., Ltd., arithmetic mean particle size: 22nm, nitrogen adsorption specific surface area: 119m² 2 / g

[0099] FEF carbon black: Manufactured by Seast SO Tokai Carbon Co., Ltd.; Arithmetic mean particle size: 43 nm; Nitrogen adsorption specific surface area: 42 m² 2 / g

[0100] Processing oil: Sunpar 2280, manufactured by Sun Petroleum Company

[0101] Co-crosslinker 1: Trimethylolpropane trimethacrylate (manufactured by Hi-Cross M Fine Chemicals)

[0102] Co-crosslinking agent 2: N,N'-m-phenylenebismaleimide (manufactured by Vulnoc PM Ouchi Shinshin Chemical Co., Ltd.)

[0103] Co-crosslinking agent 3: Zinc methacrylate (manufactured by Actor ZMA Kawaguchi Chemical Co., Ltd.)

[0104] Crosslinking agent 1: (Organic peroxide system, Perhexa 25B-40 manufactured by Nichiyu Corporation, purity 40% by mass)

[0105] Crosslinking agent 2: (Organic peroxide system, manufactured by Peroxymon F-40 Japanese Oil Company, purity 40% by mass)

[0106] Polyaramid short fiber A: (RFL treated, para-type, CFH3050, manufactured by Teijin Corporation, fiber diameter 12.3μm, fiber length 3.0mm)

[0107] Polyaramid short fiber B: (RFL treated, para-type, BKD7041E manufactured by Toray DuPont, fiber diameter 17μm, fiber length 3.0mm)

[0108] Nylon staple fiber: (RFL treated, 6,6-nylon, CFN3000 manufactured by Asahi Kasei Corporation, fiber diameter 27.3μm, fiber length 3.0mm)

[0109] Polyaramid short fiber A': (RFL of polyaramid short fiber A is untreated)

[0110] (Evaluation Method)

[0111] The double-toothed V-belts obtained in the examples and comparative examples were evaluated as follows. The results are shown in Table 2. Furthermore, the relationship between the stored elastic modulus and elongation is shown in... Figure 2 .

[0112] <Storage elastic modulus E'>

[0113] Test pieces measuring 30 mm in width, 10 mm in length, and 1 mm in thickness were cut from the compressed rubber layer of the double-toothed V-belt. Based on JIS K6394:2007, the storage elastic modulus E' at 25°C was determined by tensile testing. The testing conditions were as follows: the strain at 1.3 times the load at 1% of the load strain was defined as the average strain; the strain amplitude was set to 0.1%; the frequency was set to 10 Hz; and the test temperature was set to 25°C.

[0114] <Elongation EB>

[0115] Test pieces of 50 mm in length, 10 mm in width, and 1 mm in thickness were cut from the compressed rubber layer of the double-toothed V-belt. The elongation at 25°C was measured based on JIS K6251:2017.

[0116] <With Operational Testing>

[0117] The belt running test was conducted using a continuously variable transmission (CVT) belt running test machine. Furthermore, the driven pulley was configured to bear a constant load DW (static weight) to generate a certain belt tension in the double-toothed V-belt.

[0118] Low-speed layout

[0119] A double-toothed V-belt is suspended and installed with a driving pulley winding diameter of 99mm and a driven pulley winding diameter of 263mm. A constant load DW of 1800N is applied to the driven pulley to generate belt tension, thus forming a low-speed configuration.

[0120] Subsequently, at an ambient temperature of 30°C, the drive pulley is rotated at 7500 rpm to initiate low-speed belt operation. The belt is then operated until the double-toothed V-belt is cut, and the time from the start of belt operation to cut is defined as the low-speed belt life. Furthermore, the maximum belt operation time is set to 200 hours.

[0121] High-speed layout

[0122] A double-toothed V-belt is suspended and installed with a driving pulley winding diameter of 210mm and a driven pulley winding diameter of 165mm. The driven pulley is subjected to a constant load DW of 2300N to generate belt tension, thus forming a high-speed layout.

[0123] Subsequently, at an ambient temperature of 100°C, the drive pulley is rotated at 9400 rpm to initiate high-speed belt operation. The belt is then operated until the double-toothed V-belt is cut; the time from the start of belt operation to cut is defined as the high-speed belt life. Furthermore, the maximum belt operation time is set to 50 hours.

[0124] [Table 2]

[0125]

[0126] The double-tooth V-belts obtained in Comparative Examples 1 and 2 have short belt life in low-speed configurations, while the double-tooth V-belts obtained in Comparative Examples 3 to 5 have short belt life and poor durability in high-speed configurations.

[0127] In contrast, the double-tooth V-belts obtained in Embodiments 1 to 6 of the present invention have long belt life and excellent durability, regardless of whether they are in a low-speed or high-speed layout.

Claims

1. A V-shaped belt, characterized in that, It has: an attached rubber layer, and an embedded core wire extending along the length direction of the strip; and A compression rubber layer is stacked on the inner periphery of the adhesive rubber layer. Regarding the rubber composition forming the compressed rubber layer, it comprises an ethylene-α-olefin elastomer, an unsaturated carboxylic acid metal salt, a crosslinking agent, and para-reactive polyaramid short fibers bonded with resorcinol-formaldehyde latex, and when the value of the storage modulus (E') of the rubber composition test piece taken in the belt width direction, based on Japanese Industrial Standard K6394, at a frequency of 10 Hz and a test temperature of 25°C, and measured by a tensile method with a dynamic strain of 0.1% strain, is set as X (MPa), and the value of the elongation of the rubber composition test piece taken in the belt length direction is set as Y (%), the following (1) and (2) are simultaneously satisfied: （1）X＞800 (2) Y>-42.05·ln(X)+340.

2. The V-shaped belt according to claim 1, characterized in that, It is a toothed V-belt.

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