WO2018043355A1 - V-ribbed belt and use thereof - Google Patents

Abstract

Provided is a v-ribbed belt comprising a compression rubber layer that has a plurality of v-ribbed sections that extend in the longitudinal direction of the belt and are parallel to each other and has a friction transmission face, at least a portion of which can contact a v-ribbed groove of a pulley, wherein the friction transmission face of the compression rubber layer is formed with a vulcanizate of a rubber composition containing a rubber component and an agent to improve sound proofing, and the v-ribbed angle of the v-ribbed portion is 5° to 9° larger than the v-ribbed groove angle of the pulley.

Description

V-ribbed belt and its use

The present invention relates to a V-ribbed belt used for driving an automotive engine accessory, and more specifically, improving the fuel efficiency while stabilizing the frictional state of a friction transmission surface and maintaining sound resistance (quietness). The present invention relates to a V-ribbed belt that can be reduced and its use.

An auxiliary machine such as an alternator, a water pump, and a power steering pump is attached to an internal combustion engine (engine) such as an automobile, and these auxiliary machines are connected via a power transmission mechanism in which a transmission belt is suspended by an engine crankshaft. It is generally mechanically driven.

In recent years, there has been an increasing demand for technologies for achieving both fuel saving and soundproofing (quietness) in automobile engines. With regard to fuel efficiency, from the viewpoint of reducing engine friction loss and improving fuel efficiency, it is desirable to reduce the torque cross in the power transmission mechanism (the difference between the drive torque on the crankshaft and the driven torque on the driven shaft (auxiliary)). It is rare.

Specifically, a V-ribbed belt is used as a transmission belt used in an engine accessory drive system, and means for reducing torcross is proposed for the V-ribbed belt.

Japanese Patent Application Laid-Open No. 2010-276127 (Patent Document 1) proposes a V-ribbed belt in which the torque loss is reduced by reducing internal loss (self-heating) using a rubber composition having a small loss tangent tan δ. . In Japanese Patent Laid-Open No. 2013-177967 (Patent Document 2), the torcross is reduced by arranging the position of the core wire on the inner peripheral side to reduce the bending stress (belt bending loss) of the core wire. V-ribbed belts have been proposed.

However, although these V-ribbed belts can achieve a certain degree of torque reduction, in a portion where the pulley diameter is small, such as an alternator that is a power generation device, the amount of bending of the wound belt is large, and the torque loss is not reduced. It is enough. Since the part where such a large torque cross is generated greatly affects the friction loss of the engine, further reduction of the torque cross is a major issue.

On the other hand, with respect to sound generation resistance in an accessory drive system such as an automobile engine, the friction coefficient of the belt surface (pulley engagement surface) in contact with the pulley is reduced to easily occur when pulley misalignment (axial misalignment) occurs. Improvement of noise and noise caused by the stick-slip phenomenon has become an issue.

Stick-slip phenomenon refers to self-excited vibration caused by microscopic adhesion between friction surfaces and repeated sliding, and the friction coefficient decreases with increasing sliding speed, or from static friction. This is a phenomenon that occurs when discontinuous friction drop occurs when moving to dynamic friction. Even in the case of a V-ribbed belt, if the friction coefficient of the transmission surface that is in friction with the pulley is high (particularly high in adhesiveness), sticking and sticking (slip) are repeated between the friction between the belt and the pulley. A slip phenomenon (vibration) occurs, and abnormal noise (squealing noise) occurs at the stage of transition from adhesion to slipping. In view of this, a means has been proposed in which an additive (soundproofing improver) for improving sound resistance is blended to reduce the friction coefficient of the friction transmission surface and suppress the generation of abnormal noise.

For example, Japanese Patent Application Publication No. 2007-70592 (Patent Document 3) uses ultra high molecular weight polyethylene powder, Japanese Patent Application Publication No. 2009-168243 (Patent Document 4) uses a flat inorganic powder, and friction transmission surface. There has been proposed a method for reducing the coefficient of friction by blending with the compressed rubber layer constituting the material.

However, in these methods, although the friction coefficient can be reduced, the ultrahigh molecular weight polyethylene powder and the inorganic powder are compounding agents that increase the internal loss (tan δ), and have the disadvantage that the torque loss becomes large.

Furthermore, stick-slip noise that occurs during running under water is also a problem. Specifically, if the wettability of the friction transmission surface is low and the water ingress state between the belt and pulley (between the belt and the pulley) is not uniform, the friction coefficient is high at locations where water has not entered (dry state). On the other hand, at the place where water has infiltrated (water-impregnated state), the friction coefficient is partly lowered, so that the friction state becomes unstable and a stick-slip sound is generated. Here too, a means has been proposed in which a soundproofing improver is blended to improve the affinity of the friction transmission surface for water to suppress the generation of abnormal noise.

In Japanese Patent Laid-Open No. 2008-185162 (Patent Document 5), a friction transmission surface is formed with a rubber composition in which 1 to 25 parts by mass of a surfactant is blended with 100 parts by mass of an ethylene / α-olefin elastomer. A friction transmission belt is disclosed. Furthermore, the Japanese Patent 2007-232205 (Patent Document 6), the ethylene · alpha-olefin elastomer 100 parts by weight, solubility parameter ^{8.3 ~ 10.7 (cal / cm 3} ) 1 / A friction transmission belt in which a friction transmission surface is formed with a rubber composition containing 10 to 25 parts by weight of the plasticizer ² is disclosed. In these friction transmission belts, the affinity between the rubber (ethylene-α-olefin elastomer) that forms the friction transmission surface and water is increased by blending surfactants and plasticizers, so that noise caused by stick-slip is reduced. Decrease and improve sound resistance when wet.

However, in these belts, surfactants and plasticizers that have exuded to the friction transmission surface stabilize the friction between the belt and pulley, but the behavior of the surfactants and plasticizers in the rubber is unstable. Or, the internal loss (tan δ) increases, and the torque cross increases.

That is, in the compounding design of the rubber composition constituting the V-ribbed belt, the sound resistance (silence) and the fuel saving (torque cross reduction) are contradictory characteristics, and it is difficult to achieve both by compounding design alone. there were.

On the other hand, Japanese Utility Model Publication No. 63-147951 (Patent Document 7) discloses a V-belt between a driving V pulley and a driven V pulley as a power transmission V-belt device that can prevent jerky oscillation and noise at the start. in hung and comprising transmission, the V-belt angle theta ₁ a power transmission V-belt apparatus having an increased 5 ~ 15 ° than the groove angle theta ₂ of the V-pulley is disclosed. Examples of the V belt include a wrapped belt, a low edge belt, a low edge cogged belt, and a rib star belt.

In Japanese Patent Laid-Open No. 8-184347 (Patent Document 8), as a V-ribbed belt in which sound and noise during belt running are reduced, para-aramid fibers are fibrillated and protruded on the rib surface, and the rib portion A V-ribbed belt is disclosed in which the rib angle, which is the V-shaped angle, is 42 to 50 °. This document describes that the rib angle is 2 to 10 ° larger than the angle of the V-shaped groove portion of the pulley. In the embodiment, the rib angle is 2.5 ° or 4.5 ° larger. In this document, chloroprene rubber, hydrogenated nitrile rubber, natural rubber, CSM, and SBR are exemplified as the rubber of the belt material, and chloroprene rubber is used in the examples.

Japanese Patent Application Laid-Open No. 2000-74154 (Patent Document 9) discloses that the heat resistance life of the belt is improved without substantially reducing the transmission performance, and the core wires exposed at both end portions of the belt are short during operation. As a V-ribbed belt that does not peel off over time, a V-ribbed belt in which the rib angle is set to 10 ± 2.5 ° higher than the groove angle with respect to a V-ribbed pulley having a groove angle of 36 to 50 °, or a groove angle of 36 to 45 For V-ribbed belts where the rib angle is set to 15 ± 2.5 ° or 5 ± 2.5 ° higher than the groove angle with respect to the V-ribbed pulley at 0 °, both end portions of the belt are deleted or exposed at both end portions. A V-ribbed belt with the core wire removed is disclosed.

However, Patent Documents 7 to 9 describe that the belt angle and the rib angle are made larger than the groove angle of the pulley, but there is no description about the small-diameter pulley and the torque cross (fuel saving performance), No soundproofing improver is included. Patent Document 7 does not describe the material of the belt, and Patent Document 9 does not describe details of the rib rubber.

Japanese Unexamined Patent Publication No. 2010-276127 (Claim 1, paragraph [0008]) Japanese Unexamined Patent Publication No. 2013-177967 (Claim 1, paragraphs [0001] [0012]) Japanese Unexamined Patent Publication No. 2007-70592 (Claim 1, paragraph [0010]) Japanese Unexamined Patent Publication No. 2009-168243 (Claim 1, paragraph [0015]) Japanese Patent Laid-Open No. 2008-185162 (Claim 1) Japanese Unexamined Patent Publication No. 2007-232205 (Claim 1) Japanese Utility Model Publication No. 63-147951 (claims for utility model registration, page 4, lines 2 to 3, page 5, lines 2 to 7) Japanese Patent Laid-Open No. 8-184347 (Claims 1 and 8, paragraphs [0001] [0014], Examples) Japanese Unexamined Patent Publication No. 2000-74154 (Claims, paragraph [0020])

An object of the present invention is to provide a V-ribbed belt that can achieve both soundproofing and fuel saving, a belt transmission device including the V-ribbed belt, and a method for reducing torcross of the belt transmission device using the V-ribbed belt. is there.

Another object of the present invention is to provide a V-ribbed belt that can reduce torcross while maintaining sound resistance against stick-slip noise and adhesive wear sound even when a sound resistance improver is blended with rubber forming a friction transmission surface. Another object of the present invention is to provide a belt transmission device provided with the V-ribbed belt and a method for reducing the torque cross of the belt transmission device using the V-ribbed belt.

Still another object of the present invention is to provide a V-ribbed belt capable of reducing the torque cross even in a small-diameter pulley such as an alternator that is a power generation device, a belt transmission device provided with the V-ribbed belt, and a torcross of the belt transmission device using the V-ribbed belt. It is to provide a method of reducing.

As a result of intensive studies to achieve the above-mentioned problems, the present inventors have determined that the V-rib angle of the V-rib portion of the V-ribbed belt provided with the compression rubber layer containing the soundproofing improver is set to 5 than the V-rib groove angle of the pulley. It has been found that by increasing the angle by 9 °, it is possible to achieve both sound resistance and fuel saving, and the present invention has been completed.

That is, the V-ribbed belt of the present invention has a plurality of V-rib portions extending in parallel with each other along the longitudinal direction of the belt, and at least a part of which is a compressed rubber having a friction transmission surface capable of contacting the V-rib groove portion of the pulley. A V-ribbed belt provided with a layer, wherein the friction transmission surface of the compressed rubber layer is formed of a vulcanized product of a rubber composition containing a rubber component and a soundproofing improver, and a V-rib angle of the V-rib portion Is 5 to 9 ° larger than the V-rib groove angle of the pulley. The V rib angle of the V rib portion is about 41 to 45 °. The pulley may include a pulley having an outer diameter of 65 mm or less. The soundproofing improver is at least one selected from the group consisting of a surfactant, a plasticizer having a solubility index greater than that of a rubber component, inorganic particles, and polyethylene resin particles (in particular, a polyethylene glycol type nonionic interface). Activator and / or ether ester plasticizer). The ratio of the polyethylene glycol type nonionic surfactant is about 2 to 20 parts by mass with respect to 100 parts by mass of the rubber component. The ratio of the ether ester plasticizer is about 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component. The rubber component may contain an ethylene-α-olefin elastomer.

The present invention includes the V-ribbed belt and a pulley having a V-rib groove portion that can be fitted to the V-rib portion of the V-ribbed belt, and the V-rib angle of the V-rib portion of the V-ribbed belt is such that the V-rib angle of the pulley. Also included are belt transmissions that are 5-9 degrees larger than the rib groove angle. The pulley may include a pulley having an outer diameter of 65 mm or less.

The present invention also includes a method of reducing the torque cross of the belt transmission device by hanging the V-ribbed belt on a pulley including a pulley having an outer diameter of 65 mm or less.

In the present invention, the V-rib angle of the V-rib portion of the V-ribbed belt having the compression rubber layer containing the sound-proofing improver is 5 to 9 ° larger than the V-rib groove angle of the pulley. And both. Specifically, even when a soundproofing improver, which is a foreign substance, is blended with the rubber forming the friction transmission surface, the torque loss can be reduced while maintaining the soundproofness against stick-slip noise and adhesive wear sound. In particular, even in a small-diameter pulley such as an alternator that is a power generator, torque cross can be reduced.

FIG. 1 is a schematic cross-sectional view showing an example of a V-ribbed belt of the present invention. FIG. 2 is a schematic perspective view for explaining the V-rib angle α of the V-rib portion of the V-ribbed belt of the present invention. FIG. 3 is a schematic cross-sectional view for explaining the V-rib groove angle β of the pulley. FIG. 4 is a schematic cross-sectional view for explaining a state in which the V-rib portion of the V-ribbed belt of the present invention is fitted in the V-rib groove portion of the pulley. FIG. 5 is a schematic diagram for explaining the dimensions of the V-ribbed belt used in the examples. FIG. 6 is a schematic diagram for explaining a method of measuring the friction loss of the V-ribbed belt in the example. FIG. 7 is a schematic diagram for explaining the sound resistance test (sound measurement in an actual vehicle) of the V-ribbed belt in the example. FIG. 8 is a schematic diagram for explaining a sound resistance test (misalignment sound measurement) of the V-ribbed belt in the example. FIG. 9 is a schematic view for explaining an adhesive wear test of the rib bottom portion of the V-ribbed belt in the example. FIG. 10 is a graph showing a simulation result of torcross by FEM analysis of Example 4 and Comparative Example 9.

[V-ribbed belt structure]
If the form of the V-ribbed belt of the present invention has a plurality of V-rib portions extending parallel to each other along the belt longitudinal direction and has a V-rib groove angle larger than the V-rib groove angle of the pulley, For example, the form shown in FIG. 1 is exemplified. FIG. 1 is a schematic sectional view showing an example of the V-ribbed belt of the present invention. A V-ribbed belt shown in FIG. 1 includes a compression rubber layer 2, an adhesive layer 4 in which a core body 1 is embedded in the belt longitudinal direction, a cover canvas (woven fabric) in order from the belt lower surface (inner circumferential surface) to the belt upper surface (back surface). , A knitted fabric, a non-woven fabric, etc.). A plurality of V-shaped grooves extending in the longitudinal direction of the belt are formed in the compressed rubber layer 2, and a plurality of V-rib portions 3 having a V-shaped cross section (reverse trapezoid) are formed between the grooves (example shown in FIG. 1). 4), and the two inclined surfaces (surfaces) of the V-rib portion 3 form a friction transmission surface and contact the pulley to transmit power (friction transmission).

The V-ribbed belt of the present invention is not limited to this form, and it is sufficient that at least a part is provided with a compression rubber layer having a transmission surface that can come into contact with the V-rib groove portion (V-groove portion) of the pulley. What is necessary is just to provide the core body embed | buried along a belt longitudinal direction between a layer and a compression rubber layer. In the V-ribbed belt of the present invention, for example, the stretch layer 5 may be formed of a rubber composition, or the core body 1 may be embedded between the stretch layer 5 and the compressed rubber layer 2 without providing the adhesive layer 4. Good. Further, the adhesive layer 4 is provided on either the compressed rubber layer 2 or the stretched layer 5, and the core 1 is disposed between the adhesive layer 4 (compressed rubber layer 2 side) and the stretched layer 5, or the adhesive layer 4 (stretched layer). 5 side) and the compressed rubber layer 2 may be embedded.

It is sufficient that at least the compressed rubber layer is formed of the rubber composition described in detail below, and the stretch layer and the adhesive layer are formed of a conventional rubber composition used as the stretch layer and the adhesive layer. As long as it is formed, it may not be formed of the same rubber composition as the compressed rubber layer. Note that the rubber composition forming the stretch layer and the adhesive layer does not need to contain a soundproofing improver.

In the V-ribbed belt according to the present invention, the V-rib angle α of the V-ribbed belt shown in FIG. 2 is larger (wide angle) than the V-rib groove angle β of the pulley shown in FIG. 3, and the angle difference (α−β) is 5 to 9 °. In the present invention, since the V-rib angle α is 5 to 9 ° larger than the V-rib groove angle β, the friction loss (torcross of the belt transmission device) can be achieved without deteriorating other characteristics such as soundproofing (silence). ) Can be reduced, but the reason can be estimated as follows. That is, since the portion where the energy loss is increased due to the large heat generation due to the compressive strain received from the pulley and is connected to the torcross is near the tip of the V-rib portion, if α> β, as shown in FIG. Even if the V rib part is fitted into the V rib groove part of the pulley, a slight gap is generated between the tip part of the V rib part and the V rib groove part, and heat generation (energy loss) near the tip part of the V rib part is generated. Can be reduced.

The angle difference between the V rib angle α and the V rib groove angle β may be 5 to 9 °, preferably 5.5 to 8.5 °, more preferably 6 to 8 ° (especially 6.5 to 7). .5 °). If the angle difference is too small, the torque cross is not reduced, and if it is too large, adhesive wear on the bottom of the V-rib portion (abnormal noise due to adhesive wear) occurs, resulting in poor sound resistance. Specifically, the V rib angle α of the V rib portion is, for example, about 35 to 50 °, preferably about 40 to 47 °, and more preferably about 41 to 45 °.

The V-ribbed belt of the present invention having such a V-rib angle is particularly effective for a small-diameter pulley having a small diameter and a large bending amount of the wound belt. This is because the torque cross becomes the largest with a small-diameter pulley having the highest surface pressure against the pulley, and the torque cross with the small-diameter pulley greatly affects the friction loss of the engine. Therefore, the V-ribbed belt of the present invention is preferably hung on a pulley including a small-diameter pulley, and the outer diameter of such a small-diameter pulley may be 65 mm or less, for example, 10 to 65 mm, preferably 30 to 60 mm, More preferably, it may be about 40 to 55 mm.

The core is not particularly limited, but normally, cores (twisted cords) arranged at a predetermined interval in the belt width direction can be used. As the core wire, high-modulus fibers, for example, the above-mentioned polyester fibers (polyalkylene arylate fibers), synthetic fibers such as aramid fibers, inorganic fibers such as carbon fibers, etc. are widely used, and polyester fibers (polyethylene terephthalate fibers, polyethylene naphthalates). Phthalate fibers) and aramid fibers are preferred. The fiber may be a multifilament yarn, for example, a multifilament yarn having a fineness of 2000 to 10000 denier (particularly 4000 to 8000 denier).

As the core wire, usually a twisted cord using multifilament yarn (for example, various twists, single twists, rung twists, etc.) can be used. The average wire diameter (fiber diameter of the twisted cord) of the core wire may be, for example, about 0.5 to 3 mm, preferably about 0.6 to 2 mm, and more preferably about 0.7 to 1.5 mm. The core wire may be embedded in the longitudinal direction of the belt, and one or a plurality of core wires may be embedded in parallel at a predetermined pitch parallel to the longitudinal direction of the belt.

In order to improve the adhesion to the rubber component, the core wire is subjected to various adhesion treatments with a resorcin-formalin-latex (RFL) liquid, an epoxy compound, an isocyanate compound, etc., and then between the stretched layer and the compressed rubber layer. (Especially, it may be embedded in the adhesive layer).

Furthermore, the stretch layer may have a reinforcing cloth, for example, a cloth material (preferably a woven cloth) such as a woven cloth, a wide angle sail cloth, a knitted cloth or a non-woven cloth. If necessary, the reinforcing cloth may be laminated on the surface of the stretched layer by performing the adhesion treatment.

[Compressed rubber layer]
The V-ribbed belt of the present invention includes a compressed rubber layer having a transmission surface at least a part of which can contact with the V-rib groove portion of the pulley. The compression rubber layer has a friction transmission surface with a rubber component and a soundproofing improver. For example, a surface layer portion formed of the rubber composition is formed on the friction transmission surface, and the other portion (inner layer portion) does not contain a soundproofing improver. Although it may be a compressed rubber layer, the entire compressed rubber layer is formed of a rubber composition containing a soundproofing improver in terms of soundproofing (particularly soundproofing over a long period of time) and productivity. A compressed rubber layer is preferred.

(Rubber component)
Examples of the rubber component include known rubber components and / or elastomers such as diene rubber [natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (nitrile rubber), hydrogenated nitrile. Rubber (including mixed polymers of hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt), etc.], ethylene-α-olefin elastomer, chlorosulfonated polyethylene rubber, alkylated chlorosulfonated polyethylene rubber, epichlorohydrin rubber, acrylic rubber Examples thereof include silicone rubber, urethane rubber, and fluorine rubber. These rubber components can be used alone or in combination of two or more. Among these rubber components, ethylene-α-olefin elastomers (ethylene-propylene rubber (EPR), ethylene-propylene rubber (EPR), free from harmful halogens, ozone-resistant, heat-resistant, cold-resistant, and economically superior) Ethylene-α-olefin rubbers such as ethylene-propylene-diene copolymers (EPDM, etc.) are preferred.

(Pronunciation improver)
In the present invention, since the friction transmission surface of the compression rubber layer contains a soundproofing improver, the friction state between the belt and the pulley can be stabilized, and not only the soundproofing performance can be improved, but also the compression rubber layer improves the soundproofing performance. Despite containing the agent, the torcross can be reduced because the V-rib portion is formed at a predetermined angle.

The proportion of the soundproofing improver can be selected from the range of about 1 to 100 parts by weight with respect to 100 parts by weight of the rubber component depending on the type of the soundproofing improver. 35 parts by mass). If the proportion of the sound-proofing improver is too small, the sound-proofing property may be lowered, and conversely if too large, the torque loss may be increased.

As the soundproofing improver, a conventional soundproofing improver for stabilizing the friction state between the belt and the pulley can be used. However, surfactants and plasticizers are used because they are excellent in soundproofing improvement effect. Inorganic particles and polyethylene resin particles are preferred. These soundproofing improvers can be used alone or in combination of two or more.

(A) Surfactant The surfactant may be either an ionic surfactant or a nonionic surfactant, and can be selected according to the type of rubber component. The rubber component is an ethylene-α-olefin elastomer. In this case, a nonionic surfactant is preferable from the viewpoint of improving sound resistance, and a polyethylene glycol type nonionic surfactant and a polyhydric alcohol type nonionic surfactant are particularly preferable.

Polyethylene glycol type nonionic surfactant is a hydrophilic group formed by adding ethylene oxide to a hydrophobic base component having a hydrophobic group such as higher alcohol, alkylphenol, higher fatty acid, higher polyhydric alcohol higher fatty acid ester, higher fatty acid amide, or polypropylene glycol. Is a nonionic surfactant.

Examples of the higher alcohol as the hydrophobic base component include C _10-30 saturated alcohols such as lauryl alcohol, tetradecyl alcohol, cetyl alcohol, octadecyl alcohol, aralkyl alcohol, and C _10-26 unsaturated alcohols such as oleyl alcohol. It can be illustrated. Examples of the alkylphenol include C _4-16 alkylphenol such as octylphenol and nonylphenol. These higher alcohols may be used alone or in combination of two or more.

Higher fatty acids of the hydrophobic base component include saturated fatty acids [eg C _10-30 saturated fatty acids such as myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, montanic acid, preferably C _12-28 saturated fatty acids, more preferably C _14-26 saturated fatty acids, particularly preferably C _16-22 saturated fatty acids and the like; oxycarboxylic acids such as hydroxystearic acid], unsaturated fatty acids [eg oleic acid, erucic acid, erucic acid, linoleic acid, linolenic acid, unsaturated _{C 10-30} fatty acids such as eleostearic acid], and others. These higher fatty acids may be used alone or in combination of two or more.

The polyhydric alcohol higher fatty acid ester is an ester of a polyhydric alcohol and the higher fatty acid and has an unreacted hydroxyl group. Examples of polyhydric alcohols include alkanediols (such as C _2-10 alkanediols such as ethylene glycol, propylene glycol, and butanediol), alkanetriols (such as glycerin, trimethylolethane, trimethylolpropane), and alkanetetraols (pentaerythritol, Examples thereof include diglycerin and the like, alkanehexaol (such as dipentaerythritol, sorbitol, and sorbit), alkaneoctaol (such as sucrose), and alkylene oxide adducts thereof (such as C _2-4 alkylene oxide adducts). These higher fatty acid esters may be used alone or in combination of two or more.

Hereinafter, when “oxyethylene”, “ethylene oxide” or “ethylene glycol” is represented by “EO”, and “oxypropylene”, “propylene oxide” or “propylene glycol” is represented by “PO”, the polyethylene glycol type Specific examples of the ionic surfactant include, for example, poly EO higher alcohol ethers (poly EO _10-26 alkyl ethers such as poly EO lauryl ether and poly EO stearyl ether), and C _10-26 such as poly EO poly PO alkyl ether. Higher alcohol-EO-PO adducts; alkylphenol-EO adducts such as polyEO octylphenyl ether and polyEO nonylphenyl ether; fatty acid such as polyEO monolaurate, polyEO monooleate and polyEO monostearate Body; glycerol mono- or di-higher fatty acid esters -EO adduct (glycerin mono- or dilaurate, glycerin mono- or dipalmitate, glyceryl mono- or distearate, EO adducts of glycerin mono- or di-C _10-26 fatty acid esters such as glycerol mono- or dioleate) Pentaerythritol higher fatty acid ester-EO adduct (pentaerythritol mono to tri C _10-26 fatty acid ester-EO adduct such as pentaerythritol distearate-EO adduct), dipentaerythritol higher fatty acid ester-EO adduct Sorbitol higher fatty acid ester-EO adduct, sorbitol higher fatty acid ester-EO adduct, poly EO sorbitan monolaurate, poly EO sorbitan monostearate, poly EO sorbitant Sorbitan fatty acid ester-EO adduct such as stearate, polyhydric alcohol fatty acid ester-EO adduct such as sucrose higher fatty acid ester-EO adduct; higher alkylamine such as polyEO laurylamino ether, polyEO stearylaminoether EO adducts; poly EO palm fatty acid monoethanol amide, poly EO lauric acid monoethanol amide, poly EO stearic acid monoethanol amide, poly EO oleic acid monoethanol amide and other fatty acid amide-EO adducts; poly EO castor oil, poly Examples thereof include oils-EO adducts such as EO hydrogenated castor oil; polyPO-EO adducts (polyEO-polyPO block copolymers and the like) and the like. These polyethylene glycol type nonionic surfactants can be used alone or in combination of two or more.

The polyhydric alcohol type nonionic surfactant is a nonionic surfactant in which a hydrophobic group such as a higher fatty acid is bonded to the polyhydric alcohol (especially alkanetriol or alkanehexaol such as glycerol, pentaerythritol, sucrose or sorbitol). It is an agent. Examples of the polyhydric alcohol type nonionic surfactant include glycerin fatty acid esters such as glycerin monostearate and glycerin monooleate, pentaerythritol fatty acid esters such as pentaerythritol monostearate and pentaerythritol beef tallow fatty acid ester, Sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, sorbitol fatty acid esters such as sorbitol monostearate, sucrose fatty acid esters, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines such as coconut fatty acid diethanolamide, Examples thereof include alkyl polyglycosides. These polyhydric alcohol type nonionic surfactants can also be used alone or in combination of two or more, and may be used in combination with the polyethylene glycol type nonionic surfactant.

Preferred surfactants are nonionic surfactants, particularly polyethylene glycol type nonionic surfactants (eg, poly EOC _10-26 alkyl ether, alkylphenol-EO adducts, polyhydric alcohol C _10-26 fatty acid ester-EO Adducts, etc.).

When the rubber component is an ethylene-α-olefin elastomer, the HLB (Hydrophile-Lipophile-Balance) value of the surfactant is, for example, 8.7 to 17, preferably 9 to 15, and more preferably 9.5 to 14 ( In particular, it is about 10 to 13.5). In the present specification and claims, the HLB value is a value calculated by the Griffin method.

The viscosity (25 ° C.) of the surfactant is, for example, about 10 to 300 MPa · s, preferably about 20 to 200 MPa · s.

The ratio of the surfactant (particularly, the polyethylene glycol type nonionic surfactant) is, for example, 1 to 25 parts by mass, preferably 2 to 20 parts by mass, and more preferably 3 to 15 parts by mass with respect to 100 parts by mass of the rubber component. Part (particularly 4 to 10 parts by mass). If the proportion of the surfactant is too small, the sound resistance may be lowered, and if too much, the torque loss may be increased.

(B) Plasticizer The plasticizer may be any plasticizer having a solubility index (Solubility Parameters: SP value) larger than that of the rubber component. For example, 8.3 to 10.7 ( cal / cm ³ ) ^1/2 , preferably 8.4 to 10.5 (cal / cm ³ ) ^1/2 , more preferably 8.5 to 10 (cal / cm ³ ) ^1/2 The plasticizer which has is preferable. The solubility index is particularly effective when the rubber component is an ethylene-α-olefin elastomer.

As the plasticizer, a conventional plasticizer having such a solubility index can be used. Examples of conventional plasticizers include aliphatic carboxylic acid plasticizers (adipic acid ester plasticizers, sebacic acid ester plasticizers, etc.), aromatic carboxylic acid ester plasticizers (phthalic acid ester plasticizers, Merit acid ester plasticizers), oxycarboxylic acid ester plasticizers, phosphate ester plasticizers, ether plasticizers, ether ester plasticizers, and the like. These plasticizers can be used alone or in combination of two or more. Of these plasticizers, when the rubber component is an ethylene-α-olefin elastomer, ether ester plasticizers are preferred because they have a large effect of improving sound resistance.

Examples of ether ester plasticizers include poly C ₂ such as poly EO dibutanoate, poly EO diisobutanoate, poly EO di-2-ethylbutyrate, poly EO di-2-ethylhexylate, poly EO didecanoate, and the like. _-4 alkylene glycol di C _2-18 fatty acid esters; poly C _2-4 alkylene oxide adducts of C _2-12 aliphatic dicarboxylic acids such as adipic acid polyEO adducts; adipic acid mono- or di (butoxyethyl) esters; And C _2-12 aliphatic dicarboxylic acid di (C _1-12 alkoxy C _2-4 alkyl) esters such as adipic acid di (2-ethylhexyloxyethyl) ester and adipic acid di (octoxyethyl) ester . These ether ester plasticizers can be used alone or in combination of two or more. Of these ether ester plasticizers, poly C _2-4 alkylene glycol di C _4-12 fatty acid esters such as poly EO di-2-ethylhexylate are preferred.

The weight average molecular weight of the plasticizer (especially ether ester plasticizer) is, for example, 300 to 2000, preferably 350 to 1500 (eg 370 to 1000), more preferably 400 in terms of polystyrene in gel permeation chromatography (GPC). About 800 (especially 450 to 600).

The proportion of the plasticizer (especially the ether ester plasticizer) is, for example, 3 to 20 parts by mass (eg 5 to 15 parts by mass), preferably 3.5 to 15 parts by mass, more preferably 100 parts by mass of the rubber component. Is about 4 to 10 parts by mass (especially 4.5 to 8 parts by mass). If the proportion of the plasticizer is too small, the sound resistance may be lowered. Conversely, if the proportion is too large, the torque loss may be increased.

(C) Inorganic particles Conventional inorganic particles can be used as the inorganic particles (inorganic filler or inorganic powder). Conventional inorganic particles include, for example, graphite, metal oxide (calcium oxide, barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide, etc.), metal carbonate (magnesium carbonate, calcium carbonate, etc.), metal silicate Salt (such as calcium silicate and aluminum silicate), metal carbide (such as silicon carbide and tungsten carbide), metal nitride (such as titanium nitride, aluminum nitride, boron nitride), metal sulfide (such as molybdenum disulfide), metal sulfate Salt (calcium sulfate, barium sulfate, etc.), clay (hydrous aluminum silicate: clay composed of clay minerals such as pyrophyllite, kaolinite, sericite, montmorillonite, bentonite, smectite), talc (hydrous magnesium silicate: talc, Soapstone, called steatite That inorganic particles), mica, alumina, silica, zeolites, diatomaceous earth, calcined 珪成 earth, such as activated clay and the like. These inorganic particles can be used alone or in combination of two or more. Of these, metal carbonates of calcium carbonate, clay and talc are preferred.

The shape of the inorganic particles is not particularly limited, and for example, a spherical shape, an elliptical shape, a polygonal shape (polygonal pyramid shape, a rectangular parallelepiped shape, a rectangular parallelepiped shape, etc.), a flat shape (plate shape, scale shape, etc.), a rod shape, a fiber shape And indefinite shape. Among these, flat shapes, indefinite shapes, etc. are widely used.

The average particle size (number average primary particle size) of the inorganic particles is, for example, about 0.1 to 100 μm, preferably about 1 to 50 μm, and more preferably about 1 to 30 μm. If the size of the inorganic particles is too small, the sound resistance may not be improved sufficiently, and conversely if too large, the mechanical properties of the belt may be deteriorated. In the present specification and claims, the average particle diameter and the aspect ratio can be measured by a method of measuring dimensions based on a scanning electron micrograph taken at 50 times, a laser diffraction scattering method, or the like.

The inorganic particles may be either non-porous or porous, but the nitrogen adsorption specific surface area by the BET method is, for example, about 5000 to 30000 cm ² / g, preferably about 6000 to 25000 cm ² / g. If the specific surface area is too small, the particles become large and the mechanical properties of the belt may be reduced. Conversely, if the surface area is too large, the particles become small and the sound resistance may not be sufficiently improved.

The apparent density of the inorganic particles is, for example, about 0.2 to 0.7 g / ml, preferably about 0.25 to 0.65 g / ml. The oil absorption of the inorganic particles is about 10 to 40 ml / 100 g, preferably about 20 to 38 ml / 100 g.

The proportion of the inorganic particles is, for example, 10 to 50 parts by weight, preferably 15 to 45 parts by weight (eg 15 to 35 parts by weight), more preferably 20 to 40 parts by weight (particularly 30 to 100 parts by weight) with respect to 100 parts by weight of the rubber component. 35 parts by mass). If the proportion of the inorganic particles is too small, the sound resistance may be reduced. Conversely, if the proportion is too large, the torque loss may be increased.

(D) Polyethylene resin particles The polyethylene resin constituting the polyethylene resin particles may be a polyethylene homopolymer (homopolymer) or a polyethylene copolymer (copolymer). Examples of the copolymerizable monomer contained in the copolymer include olefins (for example, α such as propylene, 1-butene, 1-pentene, 1-hexene, 3-methylpentene, 4-methylpentene, and 1-octene). -C _3-8 olefins), (meth) acrylic monomers (for example, (meth) acrylic acid C _1-6 alkyl esters such as methyl (meth) acrylate and ethyl (meth) acrylate), Examples thereof include saturated carboxylic acids (for example, maleic anhydride), vinyl esters (for example, vinyl acetate, vinyl propionate, etc.), dienes (for example, butadiene, isoprene, etc.), and the like. These copolymerizable monomers can be used alone or in combination of two or more. Of these copolymerizable monomers, α-C _3-8 olefins such as propylene, 1-butene, 1-hexene, 4-methylpentene and 1-octene are preferred. The proportion of the copolymerizable monomer is 30 mol% or less (for example, 0.01 to 30 mol%), preferably 20 mol% or less (for example, 0.1 to 20 mol%), more preferably 10 mol% or less (for example, 1 to 10 mol%). The copolymer may be a random copolymer, a block copolymer, or the like.

Examples of the polyethylene resin include low, medium or high density polyethylene, linear low density polyethylene, ultrahigh molecular weight polyethylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-propylene-butene- 1 copolymer, ethylene- (4-methylpentene-1) copolymer and the like. These polyethylenes can be used alone or in combination of two or more. Among these polyethylenes, polyethylenes such as medium- or high-density polyethylene and ultrahigh molecular weight polyethylene are preferable because they have a large effect of improving sound resistance.

The viscosity-average molecular weight of the polyethylene resin can be selected from a range of, for example, 10,000 or more, and is, for example, 100,000 to 9 million, preferably 150,000 to 5 million, and more preferably about 200,000 to 3 million. If the molecular weight is too small, the effect of improving sound resistance is not sufficient. In the present specification and claims, the viscosity average molecular weight can be measured according to ASTM D4020.

The density of the polyethylene-based resin can be selected from a range of about 0.9 to 0.97 g / cm ³ by a method in accordance with ASTM D792, and is, for example, 0.92 to 0.97 g from the viewpoint of a great effect of improving sound resistance. / Cm ³ , preferably 0.93 to 0.97 g / cm ³ , and more preferably about 0.94 to 0.97 g / cm ³ .

The melting point (or softening point) of the polyethylene resin is preferably not less than the processing temperature for kneading or rolling the rubber composition and not more than the vulcanization temperature, for example, 160 ° C. The following (for example, 120 to 160 ° C.), preferably 125 to 150 ° C., more preferably about 125 to 140 ° C.

Examples of the shape of the polyethylene resin particles include the shapes exemplified in the section of the inorganic particles. Of the above-mentioned shapes, as the shape of the polyethylene resin particles, particles such as a spherical shape, an ellipsoidal shape, a polygonal shape, and an indefinite shape are generally used.

The average particle size (primary particle size) of the polyethylene resin particles is, for example, about 10 to 200 μm, preferably about 20 to 150 μm, and more preferably about 25 to 120 μm. If the particle diameter of the polyethylene resin particles is too small, the sound resistance may not be sufficiently improved, and conversely if too large, the mechanical properties of the belt may be deteriorated.

The ratio of the polyethylene resin particles is, for example, 1 to 30 parts by mass (for example, 5 to 20 parts by mass), preferably 3 to 20 parts by mass, more preferably 4 to 10 parts by mass (particularly with respect to 100 parts by mass of the rubber component. 4.5 to 8 parts by mass). If the proportion of the polyethylene resin particles is too small, the sound resistance may be lowered. Conversely, if the proportion is too large, the torque loss may be increased.

(Reinforcing agent)
The rubber composition forming the compressed rubber layer may further contain a reinforcing agent in addition to the rubber component and the soundproofing improver. The reinforcing agent includes reinforcing fibers and carbon black as a reinforcing agent.

Examples of reinforcing fibers include polyolefin fibers (polyethylene fibers, polypropylene fibers, etc.), polyamide fibers (polyamide 6 fibers, polyamide 66 fibers, polyamide 46 fibers, aramid fibers, etc.), polyester fibers (polyethylene terephthalate (PET) fibers, polyethylene). C _2-4 alkylene C _6-14 arylate fiber such as naphthalate (PEN) fiber], synthetic fiber such as vinylon fiber, polyparaphenylenebenzobisoxazole (PBO) fiber; natural fiber such as cotton, hemp, wool An inorganic fiber such as carbon fiber can be exemplified. These fibers can be used alone or in combination of two or more.

Of these reinforcing fibers, at least one selected from polyamide fibers such as polyamide 66 fibers and aramid fibers, polyester fibers, and vinylon fibers is preferable. The reinforcing fiber may be fibrillated. Further, various adhesive treatments may be applied to the reinforcing fiber in the same manner as the core wire.

The reinforcing fibers may be usually contained in the compressed rubber layer in the form of short fibers, and the average length of the short fibers is, for example, 0.1 to 20 mm, preferably 0.5 to 15 mm (for example, 1 to 10 mm), More preferably, it may be about 1 to 5 mm (especially 2 to 4 mm). By orienting the short fibers in the belt width direction in the compressed rubber layer that receives a large lateral pressure and frictional force from the pulley, the lateral pressure resistance of the V-ribbed belt can be ensured. The average fiber diameter of the reinforcing fibers is, for example, about 1 to 100 μm, preferably 3 to 50 μm, more preferably 5 to 40 μm (particularly 10 to 30 μm).

Carbon black has a large particle size, particularly a large particle size carbon black having an iodine adsorption amount of 40 mg / g or less in order to improve fuel economy by reducing internal heat generation of the rubber composition forming the compressed rubber layer. Is preferably included. Examples of the large particle size carbon black include FEF, GPF, APF, SRF-LM and SRF-HM. These carbon blacks can be used alone or in combination of two or more. The number average primary particle size of the large particle size carbon black may be, for example, about 40 to 200 nm, preferably 45 to 150 nm, and more preferably about 50 to 125 nm.

Since the large particle size carbon black has a low reinforcing effect, it is preferable to use a small particle size carbon black having a small particle size and a high reinforcing effect (iodine adsorption amount higher than 40 mg / g). By using at least two types of carbon black having different particle sizes, both fuel saving and reinforcing effect can be achieved. Examples of the small particle size carbon black include SAF, ISAF-HM, ISAF-LM, HAF-LS, HAF, and HAF-HS. These carbon blacks can be used alone or in combination of two or more. The number average primary particle size of the small particle size carbon black may be less than 40 nm, for example, 5 to 38 nm, preferably 10 to 35 nm, more preferably about 15 to 30 nm.

The ratio of the average particle size of the large particle size carbon black to the average particle size of the small particle size carbon black is the former / the latter = 1.5 / 1 to 3/1, preferably 1.7 / 1 to 2. It may be about 7/1, more preferably about 1.8 / 1 to 2.5 / 1.

The mass ratio of the large particle size carbon black to the small particle size carbon black is within a range where both fuel saving and reinforcing effect can be achieved, for example, the former / the latter = 20/80 to 55/45, preferably 25 / It may be about 75 to 50/50, more preferably about 30/70 to 50/50. In addition, if there is too much ratio of small particle size carbon black among carbon black, there exists a possibility that a fuel-saving property may fall, and there exists a possibility that a reinforcement effect may fall when there are too many large particle size carbon blacks.

The proportion of the reinforcing agent may be 40 parts by mass or more based on 100 parts by mass of the rubber component, for example, 50 to 200 parts by mass, preferably 60 to 180 parts by mass, more preferably 80 to 150 parts by mass (particularly 100 parts by mass). (About 120 parts by mass). In the present invention, even when the proportion of the reinforcing agent is large, the torcloth can be reduced.

The proportion of the reinforcing fibers may be 80 parts by mass or less (for example, 0 to 80 parts by mass) with respect to 100 parts by mass of the rubber component, for example, 60 parts by mass or less (for example, 1 to 60 parts by mass), preferably 50 parts by mass. Part or less (for example, 5 to 50 parts by mass), more preferably about 40 parts by mass or less (for example, 10 to 40 parts by mass). If the proportion of reinforcing fibers is too large, there is a possibility that the torque cross cannot be reduced.

The proportion of carbon black may be 10 parts by mass or more with respect to 100 parts by mass of the rubber component, for example, 20 to 180 parts by mass, preferably 30 to 150 parts by mass, more preferably 50 to 120 parts by mass (particularly 60 parts). (About 100 parts by mass).

(Other plasticizers)
The rubber composition for forming the compression rubber layer further includes other plasticizer (or softener) having a solubility index equal to or lower than the solubility index of the rubber component, in addition to the rubber component and the soundproofing improver. Also good. The other plasticizer is, for example, 6.0 to 8.1 (cal / cm ³ ) ^1/2 , preferably 6.5 to 8.0 (cal / cm) when the rubber component is an ethylene-α-olefin elastomer. ³ ) ^1/2 , more preferably, a plasticizer having a solubility index of about 7.0 to 7.8 (cal / cm ³ ) ^1/2 . Examples of other plasticizers include oils such as paraffin oil, naphthenic oil, and process oil.

The ratio of the other plasticizer (softener) may be 30 parts by mass or less with respect to 100 parts by mass of the rubber component, for example, 1 to 30 parts by mass, preferably 3 to 25 parts by mass, and more preferably 5 to 5 parts by mass. About 20 parts by mass (particularly 7 to 15 parts by mass).

(Vulcanizing agent and co-crosslinking agent)
The rubber composition forming the compression rubber layer may further contain a vulcanizing agent in addition to the rubber component and the soundproofing improver.

As the vulcanizing agent (or cross-linking agent), conventional components can be used depending on the type of rubber component. For example, organic peroxides (diacyl peroxide, peroxy ester, dialkyl peroxide, etc.), oximes (quinone) Examples thereof include dioximes), guanidines (diphenylguanidine, etc.), metal oxides (magnesium oxide, zinc oxide, etc.), sulfur vulcanizing agents and the like. These vulcanizing agents can be used alone or in combination of two or more. When the rubber component is an ethylene-α-olefin elastomer, organic peroxides, sulfur-based vulcanizing agents and the like are generally used as vulcanizing agents.

The proportion of the vulcanizing agent can be selected from a range of about 1 to 20 parts by mass with respect to 100 parts by mass of the rubber component depending on the types of the vulcanizing agent and the rubber component. For example, the ratio of the organic peroxide as the vulcanizing agent is 1 to 8 parts by weight, preferably 1.5 to 5 parts by weight, and more preferably about 2 to 4.5 parts by weight with respect to 100 parts by weight of the rubber component. It is.

The rubber composition forming the compression rubber layer may further contain a co-crosslinking agent such as bismaleimides (arene bismaleimide such as N, N′-m-phenylene dimaleimide or aromatic bismaleimide).

The ratio of the co-crosslinking agent can be selected from the range of about 0.01 to 10 parts by weight, for example, 0.1 to 10 parts by weight, preferably 0.5 to 6 parts by weight, more preferably 100 parts by weight of the rubber component. Is about 1 to 5 parts by mass.

(Other additives)
The rubber composition forming the compression rubber layer may contain a conventional additive as another additive in addition to the rubber component and the soundproofing improver.

Examples of conventional additives include vulcanization accelerators, vulcanization retarders, processing agents or processing aids (stearic acid, metal stearate, wax, paraffin, fatty acid amide, etc.), stabilizers or anti-aging agents ( UV absorbers, antioxidants, anti-aging agents or heat stabilizers, anti-bending cracking agents, anti-ozone degradation agents, etc.), coloring agents, adhesion improvers [resorcin-formaldehyde cocondensates, hexamethoxymethyl melamine, etc. Melamine resins, co-condensates thereof (resorcin-melamine-formaldehyde co-condensate, etc.), tackifiers, plasticizers, coupling agents (silane coupling agents, etc.), lubricants, flame retardants, antistatic agents Etc. may be included. These other additives can be used alone or in combination of two or more.

The ratio of these other additives can be selected from a conventional range depending on the type, for example, about 0.1 to 5 parts by mass (particularly 0.5 to 3 parts by mass) with respect to 100 parts by mass of the rubber component. It may be.

[Manufacturing method of V-ribbed belt]
The method for producing the V-ribbed belt of the present invention is not particularly limited, and a known or conventional method can be adopted. For example, a compressed rubber layer, an adhesive layer in which a core body is embedded, and an extension layer are each formed from an unvulcanized rubber composition and laminated, and the laminated body is molded into a cylindrical shape with a molding die, and added. It can be formed by forming a sleeve by vulcanization and cutting the vulcanized sleeve to a predetermined width. More specifically, the V-ribbed belt can be manufactured by the following method.

(First manufacturing method)
First, a stretch layer sheet is wound around a cylindrical molding mold having a smooth surface, and a core wire (twisted cord) forming a core is spirally spun on the sheet, and further, an adhesive layer sheet and compressed rubber A layered sheet is sequentially wound to produce a molded body. Thereafter, a jacket for vulcanization is placed on the molded body, the mold (molding die) is accommodated in a vulcanizing can, vulcanized under predetermined vulcanization conditions, and then removed from the molding mold to form a cylindrical shape. A vulcanized rubber sleeve is obtained. The outer surface (compressed rubber layer) of the vulcanized rubber sleeve is polished with a grinding wheel to form a plurality of ribs, and then the vulcanized rubber sleeve is cut to a predetermined width in the longitudinal direction of the belt using a cutter. To make a V-ribbed belt. By reversing the cut belt, a V-ribbed belt provided with a compressed rubber layer having a rib portion on the inner peripheral surface can be obtained.

(Second manufacturing method)
First, a cylindrical inner mold with a flexible jacket attached to the outer peripheral surface is used as the inner mold, and an unvulcanized stretch layer sheet is wound around the outer peripheral flexible jacket, and a core is formed on the sheet. The core wire to be spirally spun and wound with an unvulcanized compressed rubber layer sheet to produce a laminate. Next, as an outer mold that can be attached to the inner mold, a cylindrical outer mold in which a plurality of rib molds are engraved on the inner peripheral surface is used, and an inner mold in which the laminate is wound is provided in the outer mold. Install concentrically. Thereafter, the flexible jacket is expanded toward the inner peripheral surface (rib type) of the outer mold, and the laminate (compressed rubber layer) is press-fitted into the rib mold and vulcanized. Then, after extracting the inner mold from the outer mold and removing the vulcanized rubber sleeve having a plurality of ribs from the outer mold, the vulcanized rubber sleeve is cut to a predetermined width in the longitudinal direction of the belt using a cutter. Finish the ribbed belt. In the second manufacturing method, a laminated body including an extension layer, a core body, and a compressed rubber layer can be expanded at a time to be finished into a sleeve (or V-ribbed belt) having a plurality of ribs.

(Third production method)
In connection with the second production method, for example, a method disclosed in Japanese Patent Application Laid-Open No. 2004-82702 (only a compression rubber layer is expanded to form a preform (semi-vulcanized state), A method in which the core body is expanded and pressure-bonded to the preform, and vulcanized and integrated into a V-ribbed belt) may be employed.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In the following examples, the raw materials used in the examples and the measurement methods or evaluation methods for each physical property are shown below. Unless otherwise specified, “part” and “%” are based on mass.

[material]
EPDM: “EPT2060M” manufactured by Mitsui Chemicals, Inc.
Nylon short fiber: 66 nylon, average fiber diameter 27 μm, average fiber length 3 mm
Cotton short fiber: Denim, average fiber diameter 13μm, average fiber length 6mm
Zinc oxide: “Zinc oxide 3 types” manufactured by Shodo Chemical Industry Co., Ltd.
Stearic acid: Tsubaki stearic acid manufactured by NOF Corporation
Carbon black HAF: “Seast 3” manufactured by Tokai Carbon Co., Ltd., average particle size 28 nm
Carbon black FEF: “Seast SO” manufactured by Tokai Carbon Co., Ltd., average particle size 43 nm
Hydrous silica: “Nippil VN3” manufactured by Tosoh Silica Corporation
Paraffinic oil (softener): “Diana Process Oil PW-90” manufactured by Idemitsu Kosan Co., Ltd.
Surfactant: Polyoxyalkylene alkyl ether, “New Coal 2304-Y” manufactured by Nippon Emulsifier Co., Ltd.
Ether ester plasticizer: “RS-700” manufactured by ADEKA Corporation
Calcium carbonate: “Whiteon SSB” manufactured by Shiraishi Calcium Co., Ltd.
Clay (Kaolinite): "Hard Top Clay" manufactured by Shiraishi Calcium Co., Ltd.
Clay (Montmorillonite): “Bengel A” manufactured by Hojun Co., Ltd.
Talc: “RL217” manufactured by Fuji Talc Kogyo Co., Ltd., median diameter 20 μm
Polyethylene particles: “Hi-Z Million 240S” manufactured by Mitsui Chemicals, Inc.
Organic peroxide: “Park Mill D-40” manufactured by NOF Corporation
Vulcanization accelerator A: Tetramethylthiuram disulfide (TMTD)
Vulcanization accelerator B: N-cyclohexyl-2-benzothiazyl-sulfenamide (CBS)
Co-crosslinking agent A: p, p′-dibenzylquinone dioxime, “Barunok DGM” manufactured by Ouchi Shinsei Chemical Co., Ltd.
Co-crosslinking agent B: N, N'-m-phenylene dimaleimide, "Barunok PM" manufactured by Ouchi Shinsei Chemical Co., Ltd.
Core wire: a twisted yarn cord obtained by adhering a cord of total denier 6,000, which is a 2 × 3 twisted configuration of 1,000 denier PET fiber, and twisted at an upper twist factor of 3.0 and a lower twist factor of 3.0, Core wire diameter 1.0mm

Examples 1 to 22 and Comparative Examples 1 to 18
(Manufacture of V-ribbed belt)
The rubber composition for forming an extension layer, the rubber composition for forming a compression rubber layer, and the rubber composition for forming an adhesive layer shown in Tables 1 and 2 are each kneaded using a known method such as a Banbury mixer. The kneaded rubber was passed through a calender roll to prepare a stretch layer forming sheet, a compressed rubber layer forming sheet and an adhesive layer forming sheet having a predetermined thickness.

Next, a V-ribbed belt was prepared using the following known method. First, a stretch layer sheet is wound around a cylindrical molding mold having a smooth surface, and a core wire (twisted cord) that forms a core on the stretch layer sheet is spirally spun to form an adhesive layer sheet, compressed The rubber layer sheets were sequentially wound to form a molded body. Thereafter, the molding mold is placed on a vulcanizing can with the vulcanization jacket placed on the molded body, vulcanized at a temperature of 160 ° C. for 30 minutes, and then demolded from the molding mold. A cylindrical vulcanized rubber sleeve was obtained. Then, after the outer surface (compressed rubber layer) of the vulcanized rubber sleeve is ground at a predetermined interval by a grinding wheel to form a plurality of ribs, the vulcanized rubber sleeve is formed with a predetermined width in the longitudinal direction of the belt using a cutter. And finished into a V-ribbed belt.

(V-ribbed belt dimensions)
5 and Table 3, the obtained V-ribbed belt has a distance a from the center of the core [2] to the back of the V-ribbed belt [1] of 1.00 mm, and the bottom of the core [3] to the back of the V-ribbed belt [ The distance b from the rib bottom [4] to the V-ribbed belt back [1] is 2.30 mm and the distance d from the rib tip [5] to the V-ribbed belt back [1] is 1.50 mm. 4.30 mm, rib pitch e 3.56 mm, distance h from core bottom [3] to rib bottom [4] is 0.80 mm, distance i from rib tip [5] to rib bottom [4] is 2 0.000 mm, and the distance j from the rib tip [5] to the core bottom [3] was adjusted to 2.80 mm.

[Measurement of friction loss (torcross)]
As shown in FIG. 6, a V-ribbed belt (4 ribs, length 750 mm) is wound around a two-axis running test machine composed of a driving (Dr) pulley having a diameter of 55 mm and a driven (Dn) pulley having a diameter of 55 mm. A predetermined initial tension was applied to the V-ribbed belt in the tension range of 100 to 600 N / one belt, and the difference between the driving torque and the driven torque when the driving pulley was rotated at 2000 rpm without a driven pulley was calculated as a torque cross. . The results obtained are shown in Tables 4-6. The table shows the torcloth when an initial tension of 500 N was applied.

In addition, the torque cross required by this measurement includes the torque cross resulting from the bearing of the testing machine in addition to the torque cross due to the bending loss of the V-ribbed belt. Therefore, a metal belt (material: maraging steel) considered to have a torque cross as a V-ribbed belt of substantially zero is run in advance, and the difference between the drive torque and the driven torque at this time is a torque cross due to the bearing (bearing loss). Therefore, a value obtained by subtracting the torque cross caused by the bearing from the torque cross calculated by running the V-ribbed belt (the torque cross resulting from the V-ribbed belt and the bearing) was obtained as the torque cross resulting from the single V-ribbed belt. Here, the torcross (bearing loss) to be subtracted is the torcross when the metal belt is run at a predetermined initial tension (for example, when a V-ribbed belt is run at an initial tension of 500 N / one belt, the metal belt is moved at this initial tension. (Torcross when running). The smaller the torque cross of this V-ribbed belt, the better the fuel economy. From the viewpoint of fuel economy in an automobile engine, it is preferable that the torque is reduced to 0.24 N · m or less as a guideline for torque cross.

[Sounding resistance test (measurement of pronunciation in actual vehicle)]
Using a real car engine, a V-ribbed belt is hung on the water pump pulley (diameter 107mm), crank pulley (diameter 120mm) and generator pulley (diameter 55mm) in the layout shown in Fig. 7, and belt tension: 300N / belt , Generator load: 70A, crank rotation speed: idling conditions, when the V-ribbed belt (4 ribs, length 750mm) was poured and submerged, the occurrence of abnormal stick-slip noise was confirmed. Evaluated by criteria. The results are shown in Tables 4-6.

◎: No abnormal noise was generated. ○: Small abnormal noise was generated within 3 seconds.
△: A small noise was generated within 3 seconds (can be heard in the engine room but not in the car. NG when a high level of quietness is required, but normally no problem)
X: A continuous abnormal noise of 3 seconds or more was generated.

[Soundproof test (measurement of misaligned pronunciation)]
The pronunciation resistance was also evaluated in the misalignment pronunciation test. As shown in FIG. 8, the testing machine used for the evaluation is a drive (Dr) pulley (diameter 101 mm), an idler (Id) pulley (diameter 70 mm), a driven (Dn) pulley (diameter 120 mm), and a tension (Ten) pulley. (Diameter 61 mm) was arranged, and misalignment was set at an angle of 1.5 ° between the driving pulley and the driven pulley. A V-ribbed belt (6 ribs, 1200 mm in length) was hung between each pulley of the test machine, and the drive pulley was run at a rotation speed of 1000 rpm under 25 ° C conditions. At this time, a load was applied to the drive pulley so that the belt tension was 50 N / rib. Then, the occurrence of stick-slip abnormal noise (abnormal sound heard as “curculle”) when water was poured into the belt at 100 ml / min for 1 minute was confirmed, and the evaluation was made according to the same criteria as the pronunciation measurement in an actual vehicle. The results are shown in Tables 4-6.

[Rib bottom adhesive wear test]
As shown in the layout of FIG. 9, the adhesion wear test is a test machine in which a drive (Dr) pulley (diameter 120 mm), an idler (Id) pulley (diameter 45 mm), and a driven (Dn) pulley (diameter 120 mm) are arranged in this order. Used. Specifically, a V-ribbed belt (4 ribs, 1200 mm in length) is hung on each pulley of the testing machine, the rotational speed of the driving pulley is 4900 rpm, the load of the idler pulley and the driven pulley is 11.7 kW, and the initial belt tension ( 940 N / 4 ribs) was applied, and the belt was run at an ambient temperature of 25 ° C. for 5 hours. Generation | occurrence | production of the adhesion wear (abnormal sound by adhesion | attachment which can be heard as "nematic") of the bottom part (rib bottom part) of the V rib part after driving | running | working was evaluated on the following references | standards. The results are shown in Tables 4-6.

A: Adhesive wear did not occur. O: A small amount of adhesive wear occurred, but there was no problem in running performance. X: Adhesive wear that caused problems in running occurred.

As is apparent from the results in Tables 4 to 6, in Comparative Examples 4 to 16 in which a rubber composition having a high internal loss (tan δ) was used and the angle difference α-β did not reach 5 to 9 °, the value of Torcross was Increased from 0.30 to 0.34 N · m. On the other hand, in Examples 1 to 22 in which the angle difference α-β is in the range of 5 to 9 ° even when a rubber composition having a high internal loss (tan δ) is used, the value of Torcross is 0.20 to 0.24 N・ It became small with m. In Comparative Examples 1 to 3, since the rubber composition having a low internal loss (tan δ) was used, the torque loss was small regardless of the angle difference α−β. Further, in Examples 18, 20 and 22 in which the angle difference α−β was 9 °, minute adhesive wear occurred, but the level was satisfactory for the running performance. On the other hand, in Comparative Examples 17 and 18 in which the angle difference α−β exceeds 9 °, adhesive wear that causes a problem in running occurred.

In addition, the difference between the level of “0.30 to 0.34 N · m” and the level of “0.20 to 0.24 N · m”, that is, the torque cross is reduced by “0.06 to 0.14 N · m”. What is done is, for example, a significant difference corresponding to an improvement of 0.2% in the fuel consumption of a light vehicle (improvement of fuel consumption by 0.1% in the automobile field is a great effect).

In Examples 1 to 6, 17 to 20, and Comparative Examples 4 to 11 and 17 to 18 using a rubber composition containing a plasticizer or a surfactant, no stick-slip noise was generated (A or B) level). In Examples 7 to 16, 21 to 22, and Comparative Examples 12 to 16 using a rubber composition containing an inorganic filler and polyethylene particles, the stick-slip noise is inferior to that of a plasticizer or a surfactant. Occurrence was minimal (○ or △ level). In contrast, in Comparative Examples 1 to 3 in which these compounding agents were not used, stick-slip noise was generated.

From the above results, it was confirmed that in the driving device combining the V-ribbed belts of Examples 1 to 22 and the V pulley, it was possible to improve fuel economy (reduce torcross) while maintaining sound resistance (quietness).

[Torcross simulation by FEM analysis]
Under the conditions of Example 4 (plasticizer 5 parts by weight, α = 43 °, β = 36 °) and Comparative Example 9 (plasticizer 5 parts by weight, α = 40 °, β = 36 °), a V-ribbed belt and a V pulley An analysis model was created, and the energy due to compressive strain, which is an index of energy loss due to heat generation, was analyzed by computer simulation. The result is shown in FIG. 10. In Example 4, in which the angle difference α−β is large and a gap with the pulley is generated at the tip of the V-rib, the energy due to the compressive strain near the tip of the V-rib is smaller. I understand that.

Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2016-166923 filed on Aug. 29, 2016, and Japanese Patent Application No. 2017-159935 filed on Aug. 23, 2017, the contents of which are incorporated herein by reference.

The V-ribbed belt of the present invention can be used as a V-ribbed belt for various belt transmission systems, and is particularly useful as a system including a small-diameter pulley such as an alternator as a power generator, for example, a V-ribbed belt for an automobile engine accessory drive system.

DESCRIPTION OF SYMBOLS 1 ... Core body 2 ... Compressed rubber layer 3 ... Rib 4 ... Adhesive layer 5 ... Stretch layer

Claims (10)

1. A V-ribbed belt having a compressed rubber layer having a plurality of V-rib portions extending in parallel with each other along the longitudinal direction of the belt, and at least a portion having a friction transmission surface capable of contacting the V-rib groove portion of the pulley. The friction transmission surface of the compressed rubber layer is formed of a vulcanized product of a rubber composition containing a rubber component and a soundproofing improver, and the V rib angle of the V rib portion is the V rib groove angle of the pulley. V-ribbed belt 5-9 ° larger than
2. The V-ribbed belt according to claim 1, wherein a V-rib angle of the V-rib portion is 41 to 45 °.
3. The V-ribbed belt according to claim 1 or 2, wherein the pulley includes a pulley having an outer diameter of 65 mm or less.
4. The soundproofing improver is at least one selected from the group consisting of a surfactant, a plasticizer having a solubility index greater than that of a rubber component, inorganic particles, and polyethylene resin particles. A V-ribbed belt according to claim 1.
5. The soundproofing improver includes a polyethylene glycol type nonionic surfactant, and the ratio of the polyethylene glycol type nonionic surfactant is 2 to 20 parts by mass with respect to 100 parts by mass of the rubber component. 5. The V-ribbed belt according to claim 4.
6. 6. The soundproofing improver includes an ether ester plasticizer, and the ratio of the ether ester plasticizer is 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component. V-ribbed belt described in 1.
7. The V-ribbed belt according to any one of claims 1 to 6, wherein the rubber component contains an ethylene-α-olefin elastomer.
8. A belt transmission device comprising: the V-ribbed belt according to any one of claims 1 to 7; and a pulley having a V-rib groove portion that can be fitted to the V-rib portion of the V-ribbed belt. A belt transmission device in which a V-rib angle of the V-rib portion is 5 to 9 ° larger than a V-rib groove angle of the pulley.
9. The belt transmission according to claim 8, wherein the pulley includes a pulley having an outer diameter of 65 mm or less.
10. A method for reducing the torque loss of a belt transmission device by hanging the V-ribbed belt according to any one of claims 1 to 7 on a pulley including a pulley having an outer diameter of 65 mm or less.
    

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