JP2006010068A - Transmission belt and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To to provide a transmission belt and its manufacturing method capable of dispensing with the blending of short fiber into a compressive rubber layer, or remarkably reducing its blending quantity when the short fiber is blended in the compressive rubber layer, reducing the noise in traveling by orienting short fiber in the longitudinal direction of the belt, and improving flexure fatigue resistance under high temperature environment, thus a flexion life of the transmission belt can be elongated. <P>SOLUTION: In this transmission belt wherein both of the compressive rubber layer 4 and an adhesive rubber layer 2 are composed of vulcanized substance of ethylene-α-olefin-diene rubber composition, and a core wire 3 is buried and adhered in the adhesive rubber layer, 0.9≤a/b≤1.2 is satisfied when the modulus of elongation of the compressive rubber layer in the belt longitudinal direction is (a), and that of the compressive rubber layer in the belt width direction is (b). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transmission belt and a method for manufacturing the same, and more particularly, without adding short fibers to the compressed rubber layer, or significantly reducing the amount of short fibers added to the compressed rubber layer, and thus reducing manufacturing costs. However, the present invention relates to a transmission belt that has low sound generation during running and excellent bending fatigue resistance in a high-temperature environment, and a method for manufacturing such a transmission belt.

  Conventionally, transmission belts mainly used for automobiles, such as low-edge type V belts and V-ribbed belts, have excellent heat resistance, oil resistance, wear resistance, etc., and as a rubber component, chloroprene rubber or hydrogenated nitrile rubber is used. It is formed from a vulcanizate of a rubber compound obtained by using a mixture of chlorosulfonated polyethylene and short fibers. In particular, in such a transmission belt, the short fibers are dispersed in the compressed rubber layer so as to be oriented in the belt width direction, thereby increasing the lateral pressure resistance of the belt, thereby suppressing undesirable deformation of the belt during running. In order to increase the transmission efficiency and to make the short fibers protrude on the surface of the compressed rubber layer forming the contact surface with the pulley, to reduce the running sound (sounding performance) due to friction with the pulley, the rubber component 100 weight 20 parts by weight or more of short fibers are blended with respect to part. Moreover, there is a tendency that the amount of the short fibers is increased against the background of increasing demand for quietness when the automobile is running.

  For example, a rubber composition comprising a compressed rubber layer containing 10 to 30 parts by weight of short fibers having a fiber length of 0.5 to 3 mm per 100 parts by weight of ethylene-α-olefin-diene rubber having an ethylene content of 60 to 75% by weight. A transmission belt made of a vulcanized product of which the above short fibers are oriented in the belt width direction is already known (see Patent Document 1).

  Thus, a transmission belt in which a compressed rubber layer is formed from a vulcanized product of a rubber compound in which short fibers are blended with ethylene-α-olefin-diene rubber, and the short fibers are oriented in the belt width direction, It is preferable because it has low sound generation and excellent bending fatigue resistance.

  However, in order to obtain a compressed rubber layer in which short fibers are dispersed, in addition to the step of bonding the short fibers in advance, the short fibers thus bonded are uniformly formed into an unvulcanized rubber compound for the compressed rubber layer. And then rolling to orient the short fibers in the direction of the uncured rubber sheet for the compression rubber layer (longitudinal direction of the belt). Thereafter, in the transmission belt obtained, the short fibers are When the belt is manufactured so that it is oriented in the belt width direction, the unvulcanized rubber sheet for compressed rubber is placed on the unvulcanized rubber sheet for the adhesive rubber layer wound around the peripheral surface of the molding drum. The process of winding so that it may orthogonally cross the circumferential direction (longitudinal direction of a belt) of a forming drum is required.

As described above, the process for producing a transmission belt having a compressed rubber layer in which short fibers are dispersed is very complicated, and since the number of processes is large, the processing cost is high, and the short fibers are also expensive. Therefore, there is a problem that the manufacturing cost of the belt becomes high.
JP 2003-012871 A

  The present invention was made in order to solve the above-described problems in a conventional transmission belt in which short fibers are dispersed in a compressed rubber layer and the short fibers are oriented in the belt width direction. When the short fibers are not blended or when the short fibers are blended in the compressed rubber layer, the blending amount is remarkably reduced, and in the resulting transmission belt, the short fibers are oriented in the belt longitudinal direction. When the tensile elastic modulus of the compression rubber layer in the direction is a and the tensile elastic modulus of the compression rubber layer in the belt width direction is b, 0.9 ≦ a / b ≦ 1.2. Compared with the manufacture of power transmission belts, the manufacturing process is simplified and shortened to reduce manufacturing costs, while sounding during running, especially the frictional noise with the pulleys described above, is low, and it is resistant to high temperature environments. Immediate bending fatigue , Therefore, an object of a long transmission belt of bending life, to provide a method of manufacturing such a transmission belt.

  According to the present invention, in the power transmission belt, the compression rubber layer and the adhesive rubber layer are both made of a vulcanized product of an ethylene-α-olefin-diene rubber compound, and the core wire is embedded and bonded in the adhesive rubber layer. When the tensile elastic modulus of the compression rubber layer in the belt longitudinal direction is a and the tensile elastic modulus of the compression rubber layer in the belt width direction is b, 0.9 ≦ a / b ≦ 1.2 A transmission belt is provided.

  According to the present invention, the ethylene-α-olefin-diene rubber, which is a rubber component of the compressed rubber layer, preferably has an ethylene content in the range of 55 to 85% by weight, and in the range of 60 to 80% by weight. More preferably.

  According to the present invention, the compressed rubber layer may consist of a vulcanizate of an ethylene-α-olefin-diene rubber blend containing short fibers, in which case the ethylene-α-olefin-diene rubber blend is The content of the short fiber is preferably in the range of 5 parts by weight or less with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber.

  According to the present invention, as one preferred embodiment, the compressed rubber layer comprises a vulcanized product of an ethylene-α-olefin-diene rubber blend containing ultrahigh molecular weight polyethylene, and the ethylene content of the ethylene-α-olefin-diene rubber. Is less than 60% by weight, and the content of the ultra high molecular weight polyethylene in the blend is in the range of 1 to 50 parts by weight with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber. A transmission belt is provided.

  Furthermore, according to the present invention, a sheet made of a rubber-drawn canvas and a first unvulcanized ethylene-α-olefin-diene rubber compound for an adhesive rubber layer is formed on the outer peripheral surface of a cylindrical molding drum in the longitudinal direction. The sheet was wound so as to coincide with the circumferential direction of the drum, and the core wire was spun into a spiral shape, and then a sheet made of the unvulcanized ethylene-α-olefin-diene rubber compound for the second adhesive rubber layer was formed in the longitudinal direction. The sheet is wound so that the direction coincides with the circumferential direction of the molding drum, and a sheet made of the unvulcanized ethylene-α-olefin-diene rubber compound for the compression rubber layer is wound on the circumferential direction of the molding drum. To form a laminated cylindrical body, which is heated under pressure, to form a sheet made of the unvulcanized rubber compound for the first and second adhesive rubber layers and the unvulcanized for the compressed rubber layer. Vulcanized rubber In the method for producing a transmission belt for vulcanizing and integrating a sheet made of a compound, the ethylene content of the unvulcanized ethylene-α-olefin-diene rubber blend for the compressed rubber layer is 55 to 85 There is provided a method for producing a transmission belt in the range of wt%, preferably in the range of 60-80 wt%.

  According to the present invention, the unvulcanized ethylene-α-olefin-diene rubber compound for the compressed rubber layer contains short fibers in an amount of 5 parts by weight or less with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber. You may go out.

  In such a method for producing a transmission belt, according to one preferred embodiment, the unvulcanized ethylene-α-olefin-diene rubber compound for the compressed rubber layer contains ultrahigh molecular weight polyethylene, and the ethylene-α-olefin-diene rubber is used. The ethylene content is 55% by weight or more and less than 60% by weight, and the ultra high molecular weight polyethylene content in the blend is 1 to 50% by weight with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber. A method is provided that is part of the scope.

  According to the present invention, the compression rubber layer is not compounded with short fibers or the amount of short fibers is remarkably reduced, and thus the production performance is reduced while the sounding performance during traveling is small and the high temperature environment is reduced. A transmission belt having excellent bending fatigue resistance can be obtained.

  In the present invention, the transmission belt includes a V-ribbed belt and a V-ribbed belt. FIG. 1 shows a cross-sectional view of a V-ribbed belt which is an example of a transmission belt. The upper surface of the belt is formed of a single layer or multiple layers of rubberized canvas 1, and an adhesive rubber layer is adjacent to this. 2 are stacked. A plurality of core wires 3 are embedded in this adhesive rubber layer so as to extend in the longitudinal direction of the belt at intervals. Further, a compressed rubber layer 4 is laminated adjacent to the adhesive rubber layer. The compressed rubber layer has ribs 5 that are spaced from each other so as to extend in the longitudinal direction of the belt. According to the present invention, as described above, short fibers (not shown) are dispersed in the compressed rubber layer in the range of 0 to 5 parts by weight with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber. May be.

  In the transmission belt according to the present invention, the compression rubber layer and the adhesive rubber layer are both made of a vulcanized product of an ethylene-α-olefin-diene rubber compound, and a core wire is embedded and bonded in the adhesive rubber layer.

  In the present invention, as the core wire, one made of a cord having high strength and low elongation made of polyester fiber, aramid fiber, glass fiber or the like is preferably used. Such a core wire is usually used after being subjected to an adhesive treatment. In this adhesion treatment, the core wire is usually immersed in resorcin-formalin-latex (RFL) and then dried by heating to form a uniform adhesion treatment layer on the surface of the core wire. If necessary, the core wire may be immersed in a solution of a polyfunctional isocyanate or polyfunctional epoxy compound, and then pretreated by heating and drying before the adhesion treatment.

  In the present invention, the ethylene-α-olefin-diene rubber, which is a rubber component for forming an adhesive rubber layer and a compressed rubber layer, is a copolymer of α-olefin, ethylene and diene (non-conjugated diene) excluding ethylene. The α-olefin excluding ethylene is preferably at least one selected from propylene, butene, hexene and octene. Among these, a preferable ethylene-α-olefin-diene rubber is ethylene-propylene-diene rubber. In such ethylene-α-olefin-diene rubber, the diene component is not particularly limited, but usually a non-conjugated diene such as 1,4-hexadiene, dicyclopentadiene or ethylidene norbornene (ENB) is appropriately used. Used for. In the ethylene-α-olefin-diene rubber, the diene component is usually in the range of 0.1 to 5.0% by weight.

  In the present invention, the ethylene-propylene-diene rubber for the adhesive rubber layer is not particularly limited, but those having an ethylene content in the range of 50 to 60% by weight are usually used. On the other hand, according to the present invention, as the ethylene-propylene-diene rubber for the compressed rubber layer, one having an ethylene content in the range of 55 to 85% by weight is used. In particular, blending of short fibers into the compressed rubber layer is used. A transmission belt having no ethylene fiber or a reduced amount of short fibers preferably has an ethylene content in the range of 60 to 80% by weight so that the sound generation performance is low during running and the strength and hardness are excellent.

  However, when an ethylene-α-olefin-diene rubber for a compressed rubber layer having an ethylene content of 55% by weight or more and less than 60% by weight is used, the ethylene-α-olefin- As compared with the case of using a diene rubber having an ethylene content of 60% by weight or more, the resulting transmission belt has a relatively high sounding performance. Therefore, when an ethylene-α-olefin-diene rubber for a compression rubber layer having an ethylene content of 55% by weight or more and less than 60% by weight is used in accordance with the present invention, such ethylene-α- It is preferable to use ultra high molecular weight polyethylene in an amount of 1 to 50 parts by weight, preferably 5 to 20 parts by weight with respect to 100 parts by weight of the olefin-diene rubber.

  Thus, when using ethylene-α-olefin-diene rubber for the compressed rubber layer having an ethylene content of 55% by weight or more and less than 60% by weight, by using ultra high molecular weight polyethylene in combination, Without adversely affecting the desired properties of the resulting transmission belt, the resulting transmission belt can be driven to a level almost equal to that obtained when ethylene-α-olefin-diene rubber having an ethylene content of 60% by weight or more is used. Pronunciation can be reduced. As described above, the ethylene-α-olefin-diene rubber for the compression rubber layer is an ethylene-α-olefin-diene rubber having an ethylene content of 55% by weight or more and less than 60% by weight even when ultrahigh molecular weight polyethylene is used in combination. You may use a short fiber in 0-5 weight part with respect to 100 weight part of propylene-diene rubbers. Here, the ultra-high molecular weight polyethylene is polyethylene having a weight average molecular weight of about 1 to 5 million, as is well known.

  However, when the blending amount of ultrahigh molecular weight polyethylene exceeds 50 parts by weight with respect to 100 parts by weight of ethylene-α-olefin-diene rubber, blending of ethylene-α-olefin-diene rubber containing ultrahigh molecular weight polyethylene in such proportion If the product is rolled (sheeted), the smoothness of the surface of the obtained sheet may be deteriorated, and a transmission belt having a compressed rubber layer obtained from such an ethylene-α-olefin-diene rubber compound Is inferior in bending fatigue resistance.

  In the present invention, an organic peroxide (organic peroxide) is preferably used as a vulcanizing agent for ethylene-propylene-diene rubber, and a co-crosslinking agent is used as necessary. Examples of the organic peroxide include diacyl peroxide, peroxy ester, t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane-3. 1,3-bis (t-butylperoxyisopropyl) benzene, 1,1-dibutylperoxy-3,3,5-trimethylcyclohexane and the like. Such an organic peroxide is usually used in the range of 1 to 10 parts by weight, preferably in the range of 1.5 to 5 parts by weight, with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber. .

  Examples of the co-crosslinking agent include TAC, 1,2-polybutadiene, unsaturated carboxylic acid metal salt, oximes, guanidine, trimethylolpropane trimethacrylate, N, Nm-phenylene bismaleimide, sulfur, and the like. . The amount of co-crosslinking agent used depends on the type of co-crosslinking agent and cannot be determined in general. For example, in the case of N, Nm-phenylene bismaleimide, 100 wt.% Of ethylene-α-olefin-diene rubber is used. Is usually used in the range of 0.2 to 10 parts by weight with respect to parts, and in the case of sulfur, usually 0.01 to 1 with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber. Used in the range of parts by weight.

  In the present invention, sulfur is also used as a vulcanizing agent. In this case, sulfur is normally used in the range of 1.5 to 10 parts by weight with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber. If necessary, the vulcanization accelerator is used in the range of 1.5 to 10 parts by weight with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber.

  As the short fibers, those made of nylon 6, nylon 66, polyester, cotton, aramid, or the like are used. Such short fibers usually have a fiber diameter in the range of 10 to 100 μm, preferably 20 to 60 μm, and a fiber length of 0.1 to 5 mm, preferably 0.5 to 3 mm. According to the present invention, as described above, short fibers may be blended in the compressed rubber layer. In this case, in the range of 5 parts by weight or less with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber. Used.

  When the amount of the short fiber in the compressed rubber layer exceeds 5 parts by weight with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber and the short fiber is oriented in the longitudinal direction of the belt, the resulting transmission belt In this case, the elastic modulus of the short fiber and the rubber are greatly different, so when bending stress is applied to the belt during the running of the belt, the stress concentrates on the interface between the short fiber and the rubber and becomes the starting point of the crack. Grows rapidly and thus cracks occur in the compressed rubber layer, resulting in poor bending fatigue resistance, and the resulting transmission belt has a short bending life.

  In a transmission belt in which short fibers are oriented and dispersed in the longitudinal direction of the belt in the compression rubber layer, the blending amount of the short fibers in the compression rubber layer determines the tensile elastic modulus of the compression rubber layer in the longitudinal direction of the transmission belt obtained. When a is a and the tensile elastic modulus of the compression rubber layer in the belt width direction is b, it is correlated with the a / b ratio. This a / b ratio is the bending fatigue resistance of the resulting transmission belt in a high temperature environment. Correlates with gender. That is, according to the present invention, as the amount of the short fiber added to the compressed rubber layer increases, the a / b ratio also increases. Here, when the a / b ratio is within a predetermined range, that is, 0 When .9 ≦ a / b ≦ 1.2, the resulting transmission belt has low sound output and excellent bending fatigue resistance, and thus has a long bending life, while the a / b ratio. If it exceeds 1.2, the tensile elastic modulus in the longitudinal direction of the belt of the compressed rubber layer becomes significantly larger than the tensile elastic modulus in the belt width direction, and the transmission belt is inferior in bending fatigue resistance in a high temperature environment. .

  In particular, according to the present invention, the compressed rubber layer is composed of a vulcanizate of an ethylene-α-olefin-diene rubber compound having an ethylene content in the range of 60 to 80% by weight, and short fibers are compounded in the compressed rubber layer. Otherwise, when 0.95 ≦ a / b ≦ 1.15, the resulting transmission belt not only has low sound output during running, but also contains short fibers in the compressed rubber layer, and the short fibers are mixed with the belt width. The conventional transmission belt is more excellent in bending fatigue resistance in a high temperature environment than the conventional transmission belt oriented in the direction, and thus has a longer bending life than the conventional transmission belt.

  According to the present invention, the unvulcanized rubber sheet comprising the unvulcanized rubber compound for the adhesive rubber layer and the compressed rubber layer is not only a vulcanizing agent but also an ethylene-α-olefin-diene rubber as described above. If necessary, in the case of a rubber compound for a normal rubber and a compressed rubber layer, such as carbon black, vulcanization accelerator, accelerator activator, softener, anti-aging agent, etc. Short fibers are mixed to prepare a rubber compound, which is kneaded with an appropriate kneading means such as a Banbury mixer, and then rolled (sheeted) to a required thickness with a calender roll.

  In the present invention, when the unvulcanized rubber sheet comprising the unvulcanized rubber compound for the compressed rubber layer contains short fibers, as described above, the short fibers are in the rolling direction of the unvulcanized rubber compound, and accordingly The unvulcanized rubber sheet is oriented in the longitudinal direction, and the longitudinal direction of the unvulcanized rubber sheet is the same as the longitudinal direction of the transmission belt to be obtained. That is, in the transmission belt according to the present invention, when the compressed rubber layer includes short fibers, the short fibers are blended in the longitudinal direction of the belt.

  The transmission belt according to the present invention can be obtained as follows using a sheet made of the unvulcanized rubber compound for a compressed rubber layer as described above. That is, after winding a rubber sheet made of an unvulcanized ethylene-α-olefin-diene rubber compound for an adhesive rubber layer in which a rubberized canvas and a core wire are embedded on the surface of a cylindrical molding drum having a smooth surface, A rubber sheet comprising the unvulcanized ethylene-α-olefin-diene rubber compound for the compressed rubber layer is wound so that the longitudinal (rolling) direction thereof coincides with the circumferential direction of the molding drum, A transmission belt can be obtained by integrally vulcanizing and bonding an unvulcanized rubber sheet for a compressed rubber layer.

  More specifically, for example, in the case of a V-ribbed belt, one or a plurality of rubberized canvases are wound around the circumferential surface of the cylindrical forming drum as described above, and the first adhesive rubber layer is wound thereon. After winding a sheet made of an unvulcanized ethylene-propylene-diene rubber compound so that its longitudinal (rolling) direction coincides with the circumferential direction of the molding drum, the core wire is spun into a spiral shape, Then, a sheet made of the unvulcanized ethylene-propylene-diene rubber compound for the second adhesive rubber layer is wound thereon so that the longitudinal (rolling) direction thereof coincides with the circumferential direction of the molding drum, and then compressed rubber A sheet made of an unvulcanized ethylene-propylene-diene rubber compound for a layer is wound so that the longitudinal (rolling) direction thereof coincides with the circumferential direction of the molding drum to form a laminate, and this is vulcanized Heating and pressing, by vulcanizing Te to obtain a cyclic compound.

  Next, the annular member is stretched between a driving roll and a driven roll, and a plurality of ribs are formed on the surface by a grinding wheel while running under a predetermined tension. Then, if this annular material is further cut between a driving roll and a driven roll and cut into a predetermined width while running, a V-ribbed belt as a product can be obtained.

  On the other hand, when forming a compressed rubber layer using a sheet made of an unvulcanized rubber compound containing conventional short fibers, the unvulcanized rubber sheet made of the unvulcanized rubber compound is: It has a strong arrangement in the rolling (longitudinal) direction, and as described above, a rubberized canvas and a cord on the surface of the cylindrical molding drum so that the short fibers are oriented in the width direction of the belt in the compressed rubber layer. After winding the rubber sheet for the adhesive rubber layer embedded in the rubber sheet, the rubber sheet for the compressed rubber layer is wound on the rubber sheet so that the orientation (rolling) direction thereof is perpendicular to the circumferential direction of the molding drum. It is necessary to form.

  As described above, the transmission belt according to the present invention is different from the conventional transmission belt in which short fibers are dispersed in the compressed rubber layer in the production of the unvulcanized rubber sheet for the compressed rubber layer. Or, it is not necessary to wind in a direction perpendicular to the direction).

  As described above, in the present invention, even if the sheet made of the unvulcanized rubber compound for the compressed rubber layer contains short fibers, the amount of the compound is limited. In the transmission belt according to the present invention obtained by using a sheet composed of an unvulcanized rubber compound, the difference in tensile properties between the longitudinal direction and the width direction of the belt of the compressed rubber layer is small.

  Here, according to the present invention, when the short fiber is not blended in the compressed rubber layer, or when the short fiber is blended in the compressed rubber layer, the blending amount is limited to the range as described above, and the compression is performed. In the rubber layer, when short fibers are oriented in the belt longitudinal direction, and the tensile elastic modulus of the compression rubber layer in the longitudinal direction of the transmission belt is a, and the tensile elastic modulus of the compression rubber layer in the belt width direction is b, By setting 0.9 ≦ a / b ≦ 1.2, it is possible to reduce the sound output during belt running and to improve the bending fatigue resistance in a high temperature environment. In the present invention, the tensile elastic modulus a of the compression rubber layer in the longitudinal direction of the transmission belt is usually in the range of 20 to 100 MPa, and preferably in the range of 30 to 60 MPa.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In each of the following Examples and Comparative Examples, the sheet made of the unvulcanized ethylene-α-olefin-diene rubber compound for the adhesive rubber layer was obtained by rolling the following rubber compound into a sheet with a calender roll.

(Unvulcanized rubber compound for adhesive rubber layer)
Ethylene-propylene-diene rubber (ethylene content 56% by weight) 100 parts by weight HAF carbon 50 parts by weight silica 20 parts by weight paraffin oil 20 parts by weight vulcanizing agent (oil sulfur) 3 parts by weight vulcanization accelerator DM 1.4 parts by weight Sulfur accelerator EZ 0.6 part by weight vulcanization accelerator TT 0.6 part by weight vulcanization aid (stearic acid) 1 part by weight vulcanization aid (zinc oxide) 5 parts by weight anti-aging agent 224 2 parts by weight anti-aging Agent MB 1 part by weight tackifier (petroleum resin) 5 parts by weight

(Unvulcanized rubber compound for compressed rubber layer)
In each of the examples and comparative examples, each of the sheets made of the unvulcanized ethylene-α-olefin-diene rubber compound for the compressed rubber layer was obtained by rolling the rubber compound shown in Table 1 into a sheet with a calender roll. It is.

(Preparation of RFL)
7.31 parts by weight of resorcin and 10.77 parts by weight of formalin (37% by weight concentration) were mixed and stirred, and an aqueous sodium hydroxide solution (solid content: 0.33 parts by weight) was added thereto and mixed and stirred. To this was added 160.91 parts by weight of water and aged for 5 hours to obtain an aqueous solution of resorcin / formalin resin (resorcin / formalin initial condensate, RF) having a solid concentration of 6.40% by weight. Chlorosulfonated polyethylene rubber (CSM) latex was added to this RF aqueous solution and aged for 12 hours to obtain resorcin-formalin latex (RFL).

(Aramid core bonding process)
As the aramid core wire, an aramid core wire (1000 de / 1 × 3, upper twist coefficient 859.9, lower twist coefficient 863.3) formed by twisting an aramid filament into a strand and twisting this strand was used. The aramid cord was immersed in a toluene solution of isocyanate (polymethylene polyphenyl polyisocyanate) (isocyanate solid content: 16% by weight) and then pre-treated by heating and drying at 250 ° C. for 40 seconds.

  Next, the pretreated aramid core wire is immersed in the RFL as the first RFL treatment, heated and dried at 250 ° C. for 80 seconds, and then immersed in the RFL as the second RFL treatment. And dried at 250 ° C. for 80 seconds. Thereafter, the aramid core wire thus RFL-treated is immersed in an adhesive solution (rubber paste) obtained by dissolving the ethylene-α-olefin-diene rubber compound for adhesive rubber layer in toluene, and then at 60 ° C. for 40 seconds. It heat-dried and the adhesion | attachment process was performed.

Example 1
(Measurement of tensile modulus of compression rubber layer)
The unvulcanized ethylene-α-olefin-diene rubber compound for compressed rubber layer shown in Table 1 is kneaded and rolled with a calender roll to form a sheet having a thickness of 0.6 mm. And vulcanized for 25 minutes to obtain a vulcanized rubber sheet having a thickness of 1 mm. From this vulcanized rubber sheet, a dumbbell A type sample was punched out according to the test method for vulcanized rubber of JIS K 6301, and this sample was subjected to dynamic strain 1. using a viscoelasticity tester (FT Rheospectr manufactured by Rheology). Measurement was performed by applying a load at 0% and a frequency of 10 Hz. The tensile elastic modulus in the longitudinal direction (belt longitudinal direction) of the vulcanized rubber sheet is a, and the tensile elastic modulus in the width direction (belt width direction, direction perpendicular to the longitudinal direction) of the vulcanized rubber sheet is b. The value of a / b is shown in Table 1 together with the tensile modulus a in the longitudinal direction (belt longitudinal direction) of the vulcanized rubber sheet.

(Manufacture of V-ribbed belt)
As described above, a sheet made of a rubber-drawn canvas and an unvulcanized ethylene-propylene-diene rubber compound for an adhesive rubber layer shown in Table 1 is wrapped around a cylindrical molding drum having a smooth surface, and then the above-described sheet is wound on the sheet. The bonded aramid core wire was spun into a spiral shape, and a sheet made of the same unvulcanized ethylene-propylene-diene rubber compound for the second adhesive rubber layer as described above was further wound thereon.

Next, a sheet made of an unvulcanized ethylene-propylene-diene rubber compound for a compressed rubber layer is wound on this so that the longitudinal direction thereof coincides with the circumferential direction of the molding drum to form a laminate, In a vulcanizing can, pressure was heated for 35 minutes at an internal pressure of 6 kgf / cm ² , an external pressure of 6 kgf / cm ² , and a temperature of 165 ° C., and steam vulcanized to obtain an annular vulcanizate. The annular vulcanizate is processed as described above, and the core wire is embedded in the adhesive rubber layer. The canvas is bonded to the upper surface of the adhesive rubber layer, and 3 is formed on the lower surface of the adhesive rubber layer. A V-ribbed belt having a circumferential length of 1000 mm having a compressed rubber layer formed with two ribs was obtained.

  The performance of the obtained V-ribbed belt was evaluated as follows. In each performance evaluation, a pulley made of material S45C having a V-rib groove corresponding to the belt was used.

(Measurement of pronunciation during driving)
As shown in FIG. 2, the V-ribbed belt 13 is wound around a driving pulley 11 and a driven pulley 12 each having a diameter of 120 mm, and an idler pulley 14 having a diameter of 70 mm and a diameter of 50 mm so that the belt running direction changes substantially at right angles. The tension pulley 15 was disposed, and a noise meter 16 was disposed inside the V-ribbed belt in the vicinity of the idler pulley. Using such a belt running test apparatus, a set load 979N is applied to the tension pulley in the horizontal direction, and there is no load applied to the driven pulley, and the drive pulley is driven at 4900 rpm and the belt is run for 300 hours. The pressure (dB) was measured to examine the sound output during running. The results are shown in Table 1. Under the above experimental conditions, when the sound pressure is 80 dB or less, it can be said that the sounding performance during actual running is low. If it is 75 dB or less, it is more preferable.

(Measurement of flex life when belt is running at high temperature)
Using the belt running test apparatus shown in FIG. 2 described above, a set load of 979 N is applied to the tension pulley 15 in the horizontal direction at an ambient temperature of 120 ° C., and a 2 kW / rib load is applied to the driven pulley 12 at 4900 rpm. The belt was stopped at regular intervals, the rib surface of the belt was examined, and the running time until cracks were visually recognized was defined as the bending life. The results are shown in Table 1.

Examples 2-7
A vulcanized rubber sheet was obtained in the same manner as in Example 1 except that the unvulcanized ethylene-α-olefin-diene rubber compound for compressed rubber layer shown in Examples 2 to 7 in Table 1 was used. In addition to measuring the elastic modulus, a V-ribbed belt was manufactured in the same manner as in Example 1, and the sound output during running and the bending life of the belt were measured. The results are shown in Table 1.

Comparative Examples 1 and 2
Except for using the unvulcanized ethylene-α-olefin-diene rubber compound for compressed rubber layer shown in Comparative Examples 1 and 2 in Table 1, respectively, a vulcanized rubber sheet was obtained in the same manner as in Example 1, While measuring the tensile elastic modulus, V-ribbed belts were produced in the same manner as in Example 1, and the sounding performance and the flex life during running were measured for each. The results are shown in Table 1.

Comparative Example 3
In the same manner as in Example 1, a sheet made of a rubber-drawn canvas and a first unvulcanized ethylene-propylene-diene rubber compound for an adhesive rubber layer was wound around a cylindrical molding drum having a smooth surface. The aramid core wire subjected to the above adhesion treatment was spun into a spiral shape, and a sheet made of the same unvulcanized ethylene-propylene-diene rubber compound for the second adhesive rubber layer as described above was further wound thereon.

Next, a sheet made of the unvulcanized ethylene-α-olefin-diene rubber compound for compressed rubber layer shown in Comparative Example 3 in Table 1 is wound on the sheet so that the longitudinal direction thereof is orthogonal to the circumferential direction of the molding drum. After forming the laminate, this was heated in a vulcanizing can at an internal pressure of 6 kgf / cm ² , an external pressure of 6 kgf / cm ² , and a temperature of 165 ° C. for 35 minutes, peroxide vulcanized, A vulcanizate was obtained. Thereafter, a V-ribbed belt was produced in the same manner as in Example 1, and the sounding performance during running and the bending life of the belt were measured in the same manner as in Example 1.

  Further, the unvulcanized ethylene-α-olefin-diene rubber compound for compressed rubber layer shown in Comparative Example 3 in Table 1 was kneaded and rolled with a calender roll to obtain a sheet having a thickness of 0.6 mm. The sheet was heated and pressurized at a temperature of 160 ° C. for 25 minutes and peroxide vulcanized to obtain a vulcanized rubber sheet having a thickness of 1 mm. About this vulcanized rubber sheet, in the same manner as in Example 1, the tensile modulus of elasticity in the line direction (belt longitudinal direction) is a, and the width direction of the vulcanized rubber sheet (belt width direction, orthogonal to the line direction). Table 1 shows the value of a / b together with the tensile elastic modulus a in the longitudinal direction of the vulcanized rubber sheet (belt longitudinal direction), where b is the tensile elastic modulus in the direction of

  As is apparent from the results shown in Table 1, according to the present invention, when the short fibers are not blended in the compressed rubber layer, or when the short fibers are blended in the compressed rubber layer, the blending amount is changed to the rubber component. In addition to 5 parts by weight or less with respect to 100 parts by weight, in the resulting transmission belt, the short fibers are oriented in the longitudinal direction of the belt so that the sound performance during running is oriented in the belt width direction. The level can be made substantially equal to that of the dispersed conventional transmission belt (Comparative Example 3).

  In addition, the transmission belt according to the present invention is also excellent in bending fatigue resistance under a high temperature environment, and according to a preferred embodiment (Examples 1 to 3), the bending belt is more resistant to bending fatigue than the conventional transmission belt. It is further improved and therefore has a longer flex life than conventional transmission belts. However, the transmission belts (Comparative Examples 1 and 2) in which the amount of the short fibers in the compressed rubber layer exceeds 5 parts by weight with respect to 100 parts by weight of the rubber component and is oriented in the belt longitudinal direction are as follows. The value of / b exceeds 1.2, and the bending life in a high temperature environment is short.

  Further, as described above, the transmission belt according to the present invention can be produced without blending the short fibers in the compressed rubber layer, or when the short fibers are blended in the compressed rubber layer, the resulting transmission belt is obtained. However, since it is oriented in the longitudinal direction of the belt, it can be produced at low cost by simplifying the production process and reducing the number of processes, unlike the case where conventional short fibers are oriented in the belt width direction.

It is a cross-sectional view of an example of a V-ribbed belt. It is a figure which shows the belt running test machine for investigating the sounding property at the time of belt running, and the bending life at the time of high temperature running.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rubberized canvas 2 ... Adhesive rubber layer 3 ... Core wire 4 ... Compression rubber layer 5 ... Rib

Claims (11)

  Both the compression rubber layer and the adhesive rubber layer are made of a vulcanized product of an ethylene-α-olefin-diene rubber compound, and in the transmission belt in which the core wire is embedded and bonded in the adhesive rubber layer, the compression in the belt longitudinal direction is performed. A transmission belt, wherein 0.9 ≦ a / b ≦ 1.2, where a is a tensile elastic modulus of the rubber layer and b is a tensile elastic modulus of the compression rubber layer in the belt width direction.   The transmission belt according to claim 1, wherein the compression rubber layer is made of a vulcanized product of an ethylene-α-olefin-diene rubber blend, and the ethylene content of the ethylene-α-olefin-diene rubber is in the range of 55 to 85% by weight.   The compression rubber layer is made of a vulcanized product of an ethylene-α-olefin-diene rubber compound containing short fibers, and the ethylene content of the ethylene-α-olefin-diene rubber is in the range of 55 to 85% by weight. The transmission belt according to claim 1, wherein the content of the short fibers is in the range of 5 parts by weight or less with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber.   The power transmission belt according to claim 2 or 3, wherein the ethylene content of the ethylene-α-olefin-diene rubber is in the range of 60 to 80% by weight.   The compression rubber layer is composed of a vulcanized product of an ethylene-α-olefin-diene rubber compound containing ultrahigh molecular weight polyethylene, and the ethylene content of the ethylene-α-olefin-diene rubber is 55% by weight or more, from 60% by weight The content of the ultra high molecular weight polyethylene in the blend is in the range of 1 to 50 parts by weight with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber. Transmission belt.   The V-ribbed belt according to any one of claims 1 to 5.   A rubber-drawn canvas is wound around the outer peripheral surface of a cylindrical molding drum, and a sheet made of the unvulcanized ethylene-α-olefin-diene rubber compound for the first adhesive rubber layer is wound on the circular drum of the molding drum. After winding so that it may correspond with the circumferential direction and spinning a core wire spirally on this, the longitudinal direction is the sheet | seat which consists of a 2nd unvulcanized ethylene-alpha-olefin-diene rubber compound for adhesive rubber layers. A sheet made of the unvulcanized ethylene-α-olefin-diene rubber compound for compressed rubber layer is wound on the drum so as to coincide with the circumferential direction of the molding drum, and the longitudinal direction thereof coincides with the circumferential direction of the molding drum. To form a laminated cylindrical body, which is heated under pressure, and a sheet comprising the first and second unvulcanized rubber compound for the adhesive rubber layer and an unvulcanized rubber compound for the compressed rubber layer The method of manufacturing a power transmission belt that the sheet is vulcanized integrally formed of said ethylene -α- olefin - method of manufacturing a power transmission belt that the ethylene content of diene rubber which is characterized in that in the range of 55 to 85 wt%.   The transmission belt according to claim 7, wherein the unvulcanized ethylene-α-olefin-diene rubber compound for the compressed rubber layer contains short fibers in an amount of 5 parts by weight or less based on 100 parts by weight of the ethylene-α-olefin-diene rubber. Production method.   The method for producing a transmission belt according to claim 7 or 8, wherein the ethylene content of the ethylene-α-olefin-diene rubber in the unvulcanized ethylene-α-olefin-diene rubber compound for the compressed rubber layer is in the range of 60 to 80% by weight. .   The unvulcanized ethylene-α-olefin-diene rubber compound for the compressed rubber layer contains ultra high molecular weight polyethylene, and the ethylene content of the ethylene-α-olefin-diene rubber is 55% by weight or more and less than 60% by weight. The method for producing a transmission belt according to claim 7 or 8, wherein the content of the ultrahigh molecular weight polyethylene in the blend is in the range of 1 to 50 parts by weight with respect to 100 parts by weight of the ethylene-α-olefin-diene rubber. . The manufacturing method of the V-ribbed belt in any one of Claims 7-10.

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