CN114962549B

CN114962549B - Trimming V-shaped belt

Info

Publication number: CN114962549B
Application number: CN202210128773.2A
Authority: CN
Inventors: 键洋介; 谷口竜也; 清水藤孝; 松田清隆
Original assignee: Bando Chemical Industries Ltd
Current assignee: Bando Chemical Industries Ltd
Priority date: 2021-02-22
Filing date: 2022-02-11
Publication date: 2023-05-09
Anticipated expiration: 2042-02-11
Also published as: TWI790927B; TW202235520A; CN114962549A

Abstract

A trim V-belt B includes a compression rubber layer (11) on the inner peripheral side of the belt, the compression rubber layer being formed of a rubber composition having an ethylene-alpha-olefin elastomer as a main component of the rubber component. The rubber composition has a peak value of tan delta at-20 ℃ or lower of 0.5 or lower in dynamic viscoelasticity in the bandwidth direction measured by scanning temperature by a stretching method.

Description

Trimming V-shaped belt

Technical Field

The invention relates to a trimming V-shaped belt.

Background

The trimmed V-belts have a wide variety of uses. Patent document 1 discloses a trim V-belt in which a compression rubber layer on the inner peripheral side is formed of a rubber composition containing an ethylene- α -olefin elastomer as a rubber component.

Patent document 1: japanese patent No. 6145170

Disclosure of Invention

Technical problem to be solved by the invention

The invention aims at: provided is a cut edge V-shaped belt having excellent cold resistance.

Technical solution for solving the technical problems

The present invention is a trim V-belt comprising a compression rubber layer on the inner peripheral side of the belt, the compression rubber layer being formed of a rubber composition containing an ethylene-alpha-olefin elastomer as a main component of a rubber component, the rubber composition having a peak value of tan delta of 0.5 or less in dynamic viscoelasticity in the belt width direction as measured by scanning temperature using a stretching method.

Effects of the invention

According to the present invention, the rubber composition forming the compression rubber layer on the belt inner peripheral side contains an ethylene- α -olefin elastomer as a main component of the rubber component, and the peak value of tan δ occurring at-20 ℃ or lower in dynamic viscoelasticity in the belt width direction measured by scanning temperature by a stretching method is 0.5 or lower, whereby excellent cold resistance can be obtained.

Drawings

Fig. 1 is a perspective view of a part of a toothed V-belt according to an embodiment;

FIG. 2 is a cross-sectional view taken along the width direction of a toothed V-belt according to an embodiment;

fig. 3 is a cross-sectional view taken along the belt length direction of the toothed V-belt according to the embodiment.

Symbol description-

B-toothed V-belts (trimmed V-belts); 10-V-shaped belt body; 11-a compression rubber layer; 11 a-lower teeth forming part; a 12-adhesion rubber layer; 13-a stretching rubber layer; 14-lower teeth; 20-core wire; 30-inner reinforcing cloth; 40-outer reinforcement cloth.

Detailed Description

The following describes embodiments in detail.

Fig. 1 to 3 show a toothed V-belt B (trimming V-belt) according to an embodiment. The toothed V-belt B according to the embodiment is an endless rubber belt used in, for example, a four-wheeled vehicle such as a home automobile, a bus, or a truck; an annular rubber belt for use in a two-wheeled vehicle such as a scooter type motorcycle; in general industrial machines such as machine tools and construction equipment, the endless rubber belt is suitable for outdoor power transmission in cold regions. The toothed V-belt B according to the embodiment has a belt length of 200mm to 5000mm, a maximum belt width of 10mm to 30mm, and a maximum belt thickness of 7.0mm to 14.0 mm.

The toothed V-belt B according to the embodiment includes a V-belt body 10, a core wire 20, an inner reinforcing cloth 30, and an outer reinforcing cloth 40.

The V-belt body 10 is formed in a cross-sectional shape cut along the belt width direction into an isosceles trapezoid. The angle formed by the two side surfaces of the V-shaped belt body 10 is, for example, 24 ° or more and 42 ° or less. The V-belt body 10 has a compression rubber layer 11 provided on the belt inner peripheral side, an adhesion rubber layer 12 provided in the middle portion, and a tension rubber layer 13 provided on the belt outer peripheral side. The lower tooth forming portions 11a are arranged at a certain pitch on the inner periphery of the compression rubber layer 11, and are formed in a sinusoidal shape in a sectional shape taken along the belt length direction.

The compression rubber layer 11 is formed of the following rubber composition: the rubber composition is obtained by adding various rubber additives to a rubber component and kneading the rubber component to form an uncrosslinked rubber composition, and then heating and pressurizing the uncrosslinked rubber composition to form a rubber composition having a crosslinked rubber component, that is, the above-mentioned rubber composition. The rubber composition forming the compression rubber layer 11 is set so that the texture direction thereof coincides with the belt width direction. The two side surfaces of the compression rubber layer 11 constitute a power transmission surface formed of a rubber composition.

The rubber composition forming the compression rubber layer 11 contains an ethylene-alpha-olefin elastomer as a main component of the rubber component. The content of the ethylene- α -olefin elastomer in the rubber component is 50 mass% or more, however, from the viewpoint of obtaining excellent cold resistance described later, it is preferably 80 mass% or more, more preferably 90 mass% or more, and still more preferably 100 mass% or more. The rubber component may contain, in addition to the ethylene- α -olefin elastomer, chloroprene rubber (hereinafter referred to as "CR"), chlorosulfonated polyethylene rubber (CSM), hydrogenated nitrile rubber (H-NBR), and the like. Examples of ethylene- α -olefin elastomers that can be cited are: ethylene propylene copolymers (EPR), ethylene propylene diene terpolymers (hereinafter referred to as "EPDM"), ethylene octene copolymers, ethylene butene copolymers, and the like. The rubber component preferably contains one or two or more of the above-mentioned ethylene- α -olefin elastomers, and more preferably contains EPDM from the viewpoint of obtaining excellent cold resistance.

From the viewpoint of obtaining excellent cold resistance, the content of ethylene in the ethylene- α -olefin elastomer is preferably 50% by mass or more and 75% by mass or less, more preferably 56% by mass or more and 65% by mass or less, and still more preferably 56% by mass or more and 60% by mass or less. In the case where the rubber component contains a plurality of ethylene- α -olefin elastomers, the ethylene content is calculated as an average value of them. When the ethylene- α -olefin elastomer contains EPDM, examples of diene components of EPDM include: ethylene norbornylene (Ethylidene norbornene; ENB), dicyclopentadiene (dicyclopentadiene), 1, 4-hexadiene, and the like. From the viewpoint of obtaining excellent cold resistance, it is preferable that the diene component is Ethylene Norbornylene (ENB) among them. In this case, the content of ENB (diene) in EPDM is preferably 3.5 mass% or more and 5.0 mass% or less, more preferably 4.0 mass% or more and 4.7 mass% or less, and still more preferably 4.2 mass% or more and 4.7 mass% or less. In the case where the rubber component contains a plurality of EPDM, the content of ENB is calculated as an average value of them. The rubber composition forming the compression rubber layer 11 has a peak value of tan delta at-20 ℃ or lower of 0.5 or lower in dynamic viscoelasticity in the bandwidth direction measured by scanning temperature by a stretching method. From the viewpoint of obtaining excellent cold resistance, the peak value of tan δ occurring at-20 ℃ or lower is preferably 0.45 or less, more preferably 0.4 or less. From the viewpoint of obtaining excellent cold resistance, the temperature at which tan δ exhibits a peak is preferably from-40 ℃ to-25 ℃, more preferably from-40 ℃ to-30 ℃, and even more preferably from-40 ℃ to-35 ℃.

From the viewpoint of obtaining excellent cold resistance, the storage modulus (storage normal modulus) at-35℃in the dynamic viscoelasticity in the bandwidth direction measured by scanning temperature with the stretching method of the rubber composition forming the compression rubber layer 11 is preferably 5.0X10 ⁸ Pa or less, more preferably 3.0X10 ⁸ Pa or below.

The dynamic viscoelasticity in the bandwidth direction of the temperature measurement was scanned by a stretching method according to JIS K6394:2007, a test piece was used, and the test piece was measured under conditions of an initial load of 0.294MPa, a dynamic deformation of 0.1%, a frequency of 10Hz, and a temperature rise rate of 2K/min.

From the viewpoint of suppressing spark generated by electric storage, the resistance value of the rubber composition forming the compression rubber layer 11 is preferably 10mΩ or less, more preferably 6mΩ or less. A pair of electrodes was placed at intervals of 216mm in length in the belt longitudinal direction, the pair of electrodes was brought into contact with the rubber composition forming the compression rubber layer 11 exposed on the belt side, a voltage of 500V was applied between the pair of electrodes, and after 5 seconds, a current value was measured, which was a value calculated based on the current value.

From the viewpoint of obtaining excellent cold resistance, it is preferable to use sulfur for the rubber composition forming the compression rubber layer 11 to crosslink the rubber component. The content of sulfur in the uncrosslinked rubber composition before crosslinking is, for example, 0.5 parts by mass or more and 3 parts by mass or less relative to 100 parts by mass of the rubber component from the viewpoint of obtaining excellent cold resistance. The rubber composition forming the compression rubber layer 11 may also use an organic peroxide to crosslink the rubber component.

In the case where sulfur is used to crosslink the rubber component, it is preferable that the rubber composition forming the compression rubber layer 11 contains a sulfenamide vulcanization accelerator and a thiuram vulcanization accelerator from the viewpoint of obtaining excellent cold resistance. From the same point of view, the sulfenamide vulcanization accelerator N-oxydiethylene-2-benzothiazolyl sulfenamide is preferable. From the same point of view, a thiuram vulcanization accelerator, tetramethylthiuram disulfide, is preferred.

From the same viewpoint, the content of the sulfanilamide vulcanization accelerator in the rubber composition is preferably 0.5 parts by mass or more and 2 parts by mass or less, more preferably 1 part by mass or more and 1.5 parts by mass or less, relative to 100 parts by mass of the rubber component. From the same viewpoint, the content of the thiuram-based vulcanization accelerator in the rubber composition is preferably 2 parts by mass or more and 4 parts by mass or less, more preferably 2.5 parts by mass or more and 3.5 parts by mass or less, relative to 100 parts by mass of the rubber component. From the same point of view, it is preferable that the content of the sulfenamide vulcanization accelerator in the rubber composition is smaller than the content of the thiuram vulcanization accelerator in the rubber composition.

From the viewpoint of obtaining excellent cold resistance and imparting conductivity to suppress spark generated by electric storage, it is preferable that the rubber composition forming the compression rubber layer 11 contains carbon black. From the same viewpoint, the content of carbon black in the rubber composition is preferably 60 parts by mass or more and 80 parts by mass or less relative to 100 parts by mass of the rubber component.

From the viewpoint of obtaining excellent cold resistance and imparting conductivity to suppress spark generated by electric storage, it is preferable that carbon black contains fast extrusion furnace black (hereinafter also referred to as "FEF"). From the same viewpoint, the content of the FEF in the rubber composition is preferably 20 parts by mass or more and 80 parts by mass or less, more preferably 30 parts by mass or more and 40 parts by mass or less, with respect to 100 parts by mass of the rubber component. From the same point of view, it is preferable that the carbon black contains high abrasion furnace black (hereinafter also referred to as "HAF") in addition to the fast extrusion furnace black. From the same viewpoint, the content of HAF in the rubber composition is preferably 20 parts by mass or more and 60 parts by mass or less, more preferably 30 parts by mass or more and 50 parts by mass or less, with respect to 100 parts by mass of the rubber component. From the same point of view, it is preferable that the content of FEF in the rubber composition is less than the content of HAF in the rubber composition.

The rubber composition forming the compression rubber layer 11 may contain oil. Preferably, the oil contains a paraffinic oil. For example, the content of the oil in the rubber composition is 10 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the rubber component.

The rubber composition forming the compression rubber layer 11 may contain short fibers dispersed in such a manner as to be oriented in the width direction. Preferably, the staple fibers comprise nylon staple fibers and/or para-aramid staple fibers (poly-paraphenylene terephthalamide staple fibers, copolymerized para-phenylene-3, 4' -oxydiphenylene terephthalamide staple fibers). For example, the content of the short fiber in the rubber composition is 10 parts by mass or more and 30 parts by mass or less relative to 100 parts by mass of the rubber component. The staple fibers have a fiber length of, for example, 1mm to 5 mm.

In addition, the rubber composition forming the compression rubber layer 11 may contain, for example, a processing aid, a vulcanization accelerator aid, a filler, an anti-aging agent, and the like. The adhesion rubber layer 12 and the extension rubber layer 13 are also formed of the following rubber compositions: the rubber composition is obtained by adding various rubber additives to a rubber component, kneading the resulting mixture to form an uncrosslinked rubber composition, and heating and pressurizing the uncrosslinked rubber composition to form a rubber composition crosslinked by a crosslinking agent, namely, the rubber composition. The adhesion rubber layer 12 and the extension rubber layer 13 may be formed of the same rubber composition as the compression rubber layer 11 or may be formed of a different rubber composition from the compression rubber layer 11. The core wire 20 is buried in the middle portion of the adhesive rubber layer 12 of the V-belt body 10 in the thickness direction to form a spiral having a pitch in the belt width direction. The core wire 20 is constituted by a yarn, for example. As the fiber material forming the core wire 20, for example, there can be mentioned: polyester fibers, aramid fibers, and the like. In order to impart the adhesion of the core wire 20 to the adhesion rubber layer 12, it is preferable to perform one or more of the following treatments before the forming process: an adhesion treatment by heating after immersing in a base treating agent containing an epoxy compound or an isocyanate compound; an adhesion treatment in which heating is performed after immersing in an RFL aqueous solution; and an adhesion treatment for drying the rubber paste after immersing in the rubber paste.

The inner reinforcing cloth 30 is provided so as to cover the inner peripheral surface of the compression rubber layer 11 of the V-belt body 10. The inner reinforcing cloth 30 is made of woven fabric, knitted fabric, nonwoven fabric, or the like, for example. As the fiber material forming the inner reinforcing cloth 30, there may be mentioned, for example: nylon fibers, polyester fibers, cotton, aramid fibers, and the like. In order to provide the inner reinforcing cloth 30 with adhesiveness to the compression rubber layer 11, it is preferable to perform one or more of the following treatments before the forming process: an adhesion treatment by heating after immersing in a base treating agent containing an epoxy compound or an isocyanate compound; an adhesion treatment in which heating is performed after immersing in an RFL aqueous solution; an adhesion treatment for drying the rubber paste after immersing in the rubber paste; and an adhesion treatment of applying a high-viscosity rubber paste to the surface on the side of the V-belt body 10 and drying the same. The inner reinforcing cloth 30 covers the lower tooth forming portion 11a of the compression rubber layer 11, thereby constituting the lower tooth 15.

The outer reinforcing cloth 40 is provided so as to cover the outer peripheral surface of the extension rubber layer 13 of the V-belt body 10. The outer reinforcing cloth 40 is woven from woven fabric, knitted fabric, nonwoven fabric, or the like, for example. As the fibrous material forming the outer reinforcing cloth 40, there may be mentioned, for example: nylon fibers, polyester fibers, cotton, aramid fibers, and the like. In order to impart adhesiveness to the outer reinforcing cloth 40 with respect to the extension rubber layer 13, it is preferable to perform one or more of the following treatments before the forming process: an adhesion treatment by heating after immersing in a base treating agent containing an epoxy compound or an isocyanate compound; an adhesion treatment in which heating is performed after immersing in an RFL aqueous solution; an adhesion treatment for drying the rubber paste after immersing in the rubber paste; and an adhesion treatment of applying a high-viscosity rubber paste to the surface on the side of the V-belt body 10 and drying the same. The toothed V-belt B according to the above embodiment can be manufactured by a known method. In the above embodiment, the toothed V-belt B has only the lower teeth 15, but the present invention is not limited to this, and a V-belt having no teeth may be used.

In the above embodiment, the toothed V-belt B includes the inner reinforcing cloth 30 and the outer reinforcing cloth 40, but is not particularly limited thereto, and may include only one of the inner reinforcing cloth 30 and the outer reinforcing cloth 40.

[ example ]

(toothed V-belt)

Toothed V-belts of each of examples 1 and 2 and comparative examples 1 and 2 were produced as follows. A commercially available toothed V-belt was purchased as comparative example 3. The toothed V-belt has the same structure as that of the above embodiment except that the inner reinforcing cloth is not provided.

Example 1 >

An uncrosslinked rubber composition sheet was prepared by adding 100 parts by mass of EPDM1 (EP 123, manufactured by JSR corporation, ethylene content: 58% by mass, and ENB (diene) content: 4.5% by mass) as a rubber component: 35 parts by mass of FEF (SEAST SO, manufactured by Tokai Carbon company) as Carbon black, 40 parts by mass of HAF (SEAST 3, manufactured by Tokai Carbon company), 14 parts by mass of paraffin processing Oil (SUNPAR 2280, manufactured by Japan Sun Oil company), 1 part by mass of stearic acid as a processing aid, 4.9 parts by mass of zinc oxide as a vulcanization accelerator, 1.6 parts by mass of sulfur (SEIMI OT, manufactured by Nippon Kanryu Industry company) as a crosslinking agent, 1.2 parts by mass of sulfenamide vulcanization accelerator (NOCCELER MSA-G, manufactured by Ouchi Shinko Chemical Industrial company, N-oxydiethylene-2-benzothiazolyl sulfenamide), 2.8 parts by mass of thiuram vulcanization accelerator (SANCELER EM-2, manufactured by Sanshin Chemical Industry company, tetramethylthiuram disulfide), and 25 parts by nylon staple fiber (CFN 1000, manufactured by Diman company, fiber length 1 mm). The uncrosslinked rubber composition sheet was disposed so that the grain direction would be the belt width direction and crosslinked to obtain a rubber composition, and a toothed V-belt in which a compression rubber layer was formed from the rubber composition was produced as example 1.

The adhesive rubber layer and the extension rubber layer are formed of other EPDM rubber compositions. The core wire is spun by twisting yarn made of polyester fiber. The outside reinforcement cloth is made of woven cloth spun by nylon 66 fiber.

Example 2 >

An uncrosslinked rubber composition sheet was produced by adding, as a rubber component, 20 parts by mass of EPDM2 (produced by noodel 4770, the Dow Chemical Company, ethylene content: 70% by mass, ENB (diene) content: 4.9% by mass) and 80 parts by mass of EPDM3 (produced by ESPRENE301, sumitomo chemical company, ethylene content: 62% by mass, ENB (diene) content: 3.0% by mass) (average ethylene content: 63.6% by mass, average ENB (diene) content: 3.38% by mass) to 100 parts by mass of the rubber component: 65 parts by mass of FEF as carbon black, 10 parts by mass of ultra-high molecular weight polyethylene particles (HI-ZEX MILLION MIL-240S, manufactured by Mitsui chemical Co., ltd.) as a filler, 10 parts by mass of paraffin-based processing oil, 0.3 part by mass of stearic acid as a processing aid, 5 parts by mass of zinc oxide as a vulcanization accelerator aid, 0.5 part by mass of an aminoketone aging inhibitor (NOCRAC 224, manufactured by Ouchi Shinko Chemical Industrial Co., 2, 4-trimethyl-1, 2-dihydroquinoline polymer), 2 parts by mass of a benzimidazole aging inhibitor (NOCRAC MB, manufactured by Ouchi Shinko Chemical Industrial Co., 2-mercaptobenzimidazole), 9.5 parts by mass of an organic peroxide 1 (PEHEXA 25B-40, manufactured by NOF CORPORATION, 40% of an active ingredient), 0.2 part by mass of sulfur as a crosslinking agent, 13 parts by mass of nylon staple fibers (fiber length 1 mm), and 3 parts by mass of para-type aromatic polyamide staple fibers (Tenofiber CFH3050, manufactured by Techra fiber length 3 mm). A toothed V-belt was produced as in example 2, except that the sheet of the uncrosslinked rubber composition was disposed so that the grain direction would be the belt width direction, and crosslinked to obtain a rubber composition, and a compression rubber layer was formed from the rubber composition.

Comparative example 1 >

An uncrosslinked rubber composition sheet was prepared by adding 100 parts by mass of EPDM4 (KELTAN 2450, manufactured by arlan xeo corporation, ethylene content: 48 mass%, ENB (diene) content: 4.1 mass%) as a rubber component: 40 parts by mass of HAF as Carbon black, 20 parts by mass of ISAF (SEAST 6, manufactured by Tokai Carbon Co., ltd.), 5 parts by mass of paraffin processing oil, 0.25 part by mass of stearic acid as a processing aid, 5 parts by mass of zinc oxide as a vulcanization accelerator, 1 part by mass of aminoketone aging inhibitor, 4.3 parts by mass (1.7 parts by mass) of organic peroxide 2 (PEROXYMON F40, manufactured by NOF CORPORATION, 40% by mass of active ingredient) as a crosslinking agent, 1 part by mass of trimethylolpropane trimethacrylate (Hi-Cross M, manufactured by Seiko chemical Co., ltd.), 18 parts by mass of nylon staple fiber (fiber length 3 mm) and 12 parts by mass of polyester staple fiber (fiber length 3 mm). A toothed V-belt was produced as in comparative example 1, except that the sheet of the uncrosslinked rubber composition was disposed so that the grain direction would be the belt width direction, and crosslinked to obtain a rubber composition, and a compression rubber layer was formed from the rubber composition.

Comparative example 2 >

An uncrosslinked rubber composition sheet was prepared by adding 65 parts by mass of a mixed rubber of CR1 (manufactured by SKYPRENE R-17, tosoh Corporation) and 35 parts by mass of CR2 (manufactured by SKYPRENE R-22, tosoh Corporation) to 100 parts by mass of the rubber component: 25 parts by mass of FEF (SEAST V, manufactured by Tokai Carbon Co., ltd.) as Carbon black, 20 parts by mass of GPF (Shintac HA-30, manufactured by Shenkou oil chemical Co., ltd.) as an aromatic processing oil, 10 parts by mass of fatty acid ester (Aflux 12NS, manufactured by PingQuanya Co., ltd.) containing an inorganic filler, 2 parts by mass of stearic acid, 1 part by mass of aromatic secondary amine-based aging inhibitor 1 (NOCRA AD-F, manufactured by Ouchi Shinko Chemical Industrial Co., octylated diphenylamine), 2 parts by mass of aromatic secondary amine-based aging inhibitor 2 (OZONNE 35, manufactured by Sec. Co., N- (1-methylheptyl) -N' -phenyl-p-phenylenediamine), 5 parts by zinc oxide as a crosslinking agent, 7.4 parts by magnesium oxide (KYOWAAG 150, manufactured by Kokukoku chemical Co., ltd.), 1.1 part by thiazole-based vulcanization accelerator (NOCCER DM, manufactured by Ouchi Shinko Chemical Industrial Co., 2-2-benzothiazolyl disulfide), and 2.1 part by guanidine-based vulcanization accelerator (NOCRAC, manufactured by NODELACER, manufactured by NOER 2.84 Co., ltd.) as a crosslinking agent. A toothed V-belt was produced as in comparative example 2, except that the sheet of the uncrosslinked rubber composition was disposed so that the grain direction would be the belt width direction, and crosslinked to obtain a rubber composition, and a compression rubber layer was formed from the rubber composition.

Comparative example 3 >

The rubber composition forming the commercially available compression rubber layer of the toothed V-belt of comparative example 3 was analyzed, and from the analysis result, it was found that the rubber component was EPDM, which contained 35 parts by mass of FEF as carbon black per 100 parts by mass of the rubber component, and further contained silica, magnesia, lime, oil, stearic acid, zinc oxide, an amine ketone aging inhibitor, a phenolic resin and a polyester staple fiber, and was crosslinked using both sulfur and an organic peroxide as a crosslinking agent.

[ Table 1 ]

(test method)

< dynamic viscoelasticity >

For each of examples 1 and 2 and comparative examples 1 and 2, a long test piece having a longitudinal direction of a grain direction of a rubber composition forming a compression rubber layer as a longitudinal direction was used, according to JIS K6394:2007, dynamic viscoelasticity was measured using the tensile method scan temperature. The measurement conditions were that the initial load was 0.294MPa, the dynamic deformation was 0.1%, the frequency was 10Hz, and the heating rate was 2K/min. Then, the peak value of tan. Delta. Appearing at-20℃or lower and the temperature at that time, and the storage modulus at-35℃were obtained.

< resistance value >

For each of examples 1 and 2 and comparative examples 1 to 3, a pair of electrodes was separated by a distance of 216mm in the belt length direction, and the pair of electrodes was brought into contact with the rubber composition forming the compression rubber layer exposed on the belt side, and a voltage of 500V was applied between the pair of electrodes, and the resistance value after 5 seconds was measured. The resistance value of 10mΩ or less was evaluated as having conductivity, and the resistance value of greater than 10mΩ was evaluated as having no conductivity.

< test for Cold resistance of Belt >)

Each of examples 1 and 2 and comparative examples 1 to 3 was wound around a driving pulley having a wheel diameter of 140mm and a driven pulley having a wheel diameter of 70mm, and pre-cooled for a predetermined period of time in an environment at-35 ℃ while applying a belt installation tension of 200 newtons. Next, a belt running test was performed in which the following cycles were performed: the driving pulley was rotated at 270rpm for 1 minute to run the belt, and thereafter, the rotation of the driving pulley was stopped to stop the belt running for 25 minutes. Then, the number of cycles until the tape is damaged is counted. The tape was run up to 1000 cycles, and was terminated.

(test results)

[ Table 2 ]

	Example 1	Example 2	Comparative example 1	Comparative example 2	Comparative example 3
						Total carbon black content	75	65	70	45	35
Sulfur content/organic peroxide content	-	0.053	0.29	-	-
						Peak tan delta value	0.395	0.386	0.591	0.688	-
tan delta peak temperature (DEG C)	-36.2	-32.2	-40.1	-26.2	-
						Storage modulus (. Times.10) ⁸ Pa)	2.74	4.71	1.06	10.53	-
Resistance MQ	0.05	1.45	0.10	0.28	＞4000
						Conductivity of conductive material	Has the following components	Has the following components	Has the following components	Has the following components	Without any means for
Cold-resistant operation test (cycle)	＞1000	＞1000	650	450	＞1000

The test results are shown in Table 2. It is found that examples 1 and 2, in which tan delta occurs at-20 ℃ or lower and has a peak value of 0.5 or lower, have high durability in belt running at low temperatures and thus are excellent in cold resistance, whereas comparative examples 1 and 2, in which tan delta occurs at-20 ℃ or lower and has a peak value of more than 0.5, have poorer cold resistance than examples 1 and 2. It was also found that example 1 and example 2 had higher conductivity than comparative example 3, which is a commercial product.

Industrial applicability

The invention is useful in the technical field of trimming V-belts.

Claims

1. A trim V-belt comprising a compression rubber layer on the inner peripheral side of the belt, the compression rubber layer being formed of a rubber composition having an ethylene- α -olefin elastomer as a main component of the rubber component, characterized in that:

the ethylene-alpha-olefin elastomer contains an ethylene-propylene-diene terpolymer containing ethylene-norbornylene as a diene component, the ethylene-norbornylene content in the ethylene-propylene-diene terpolymer being 3.5 mass% or more and 5.0 mass% or less, and,

the rubber composition contains carbon black containing a fast extrusion furnace black,

the rubber composition has a peak value of tan delta, which appears at a temperature of-40 ℃ to-25 ℃ in the dynamic viscoelasticity in the bandwidth direction measured by scanning the temperature by a stretching method, of 0.45 or less.

2. The trimmed V-belt of claim 1 wherein:

the rubber composition has a storage modulus at-35 ℃ of 5.0X10 in dynamic viscoelasticity in the bandwidth direction measured by scanning temperature by stretching method ⁸ Pa or below.

3. The trimmed V-belt of claim 1 or 2, wherein:

sulfur is used in the rubber composition to crosslink the rubber component.

4. A trim V-belt as defined in claim 3 wherein:

in the rubber composition, the sulfur is used together with an organic peroxide to crosslink the rubber component.

5. The trimmed V-belt of claim 4 wherein:

the rubber composition contains a sulfenamide vulcanization accelerator and a thiuram vulcanization accelerator.

6. The trimmed V-belt of claim 5 wherein:

the sulfenamide vulcanization accelerator is contained in the rubber composition in an amount less than the thiuram vulcanization accelerator.

7. The trimmed V-belt of claim 1 wherein:

the carbon black is contained in the rubber composition in an amount of 60 to 80 parts by mass based on 100 parts by mass of the rubber component.

8. The trimmed V-belt of claim 1 wherein:

the carbon black contains a high abrasion furnace black in addition to the fast extrusion furnace black.

9. The trimmed V-belt of claim 8 wherein:

the content of the fast extrusion furnace black in the rubber composition is less than the content of the high abrasion furnace black in the rubber composition.

10. The trimmed V-belt of claim 1 wherein:

the rubber composition has a resistance value of 10M omega or less.