JP4800794B2 - V-ribbed belt manufacturing method and V-ribbed belt - Google Patents

Description

  The present invention relates to a method for manufacturing a V-ribbed belt used for power transmission and the like, and a V-ribbed belt.

  In general, a V-ribbed belt used for power transmission is formed by laminating a compressed rubber layer in which a plurality of ribs extending in parallel with the longitudinal direction of the belt and arranged in parallel are formed on top of the compressed rubber layer. An adhesive rubber layer in which a cord made of a cord is embedded and an extension layer made of a canvas sewn on the back side of the adhesive rubber layer are provided. A canvas as an extension layer in such a general V-ribbed belt is provided to maintain the longitudinal crack resistance of the belt. For example, a plain woven fabric in which warp and weft are woven is used. It is formed by applying a rubberized process.

  However, when a general V-ribbed belt as described above is hung on a driving pulley and a driven pulley and the back surface of the belt is brought into contact engagement with an idler pulley, abnormal noise is often generated periodically. This periodic noise generation is likely to occur in the stitched area of the canvas, but also occurs in areas other than the stitched area, and occurs even if the stitched area is formed to be a flat surface. It is known that the influence of the surface condition of the canvas is one of the causes of abnormal noise generation outside this stitching region. That is, during the formation of the bias canvas or the cylindrical canvas, or while the cylindrical canvas is fitted into the belt molded body, the canvas is mechanically deformed to form the intersection angle between the warp and the weft and the warp and the weft. The size of the opening changes, the difference between the large and small portions of the opening widens, and a region where the yarn converges locally is generated. For this reason, it is known that abnormal noise is generated when the shape of the unevenness of the canvas surface in the region where the yarns locally converge differs from the shape of other regions. Further, the V-ribbed belt laminated with canvas has a problem that it is difficult to obtain a desired transmission performance because a sufficient back friction coefficient cannot be secured.

Therefore, from the viewpoint of suppressing the generation of abnormal noise and improving the transmission performance, a V-ribbed belt in which a canvas is not laminated on the back of the belt, that is, a V-ribbed belt in which an extension layer is made of a rubber composition is being proposed. However, in such a V-ribbed belt, the rubber is directly exposed on the back surface of the belt, so that when the belt is in contact with and engaged with the idler pulley, adhesive wear tends to occur on the back surface of the belt. However, there is a problem that abnormal noise such as slip noise is likely to occur. Therefore, attempts have been made to suppress the adhesive wear and suppress the generation of abnormal noise by configuring the back surface of the belt with a rubber composition containing short fibers (see, for example, Patent Document 1).
JP 2004-162899 A

  However, further research has revealed that the wear resistance and sound resistance are not sufficient only by forming the back rubber layer with a rubber composition containing short fibers. From the viewpoint of transmission performance, it is preferable that the stretch layer is composed of a rubber composition because a high friction coefficient can be ensured, but on the other hand, because the friction coefficient is high and unstable, abnormal noise such as slip noise due to rotational fluctuations and It was found that vibrations occurred on the rear idler.

  On the other hand, as a method of manufacturing a V-ribbed belt having a rubber layer on the back as described above, first, an unvulcanized stretched rubber sheet and an unvulcanized adhesive rubber sheet are sequentially spread on the inner mold, and then the core wire is spun. Then, an unvulcanized compressed rubber sheet is applied to form an endless unvulcanized belt sleeve. Then, a rubber jacket for vulcanization is extrapolated to the inner mold fitted with the unvulcanized belt sleeve and placed on the vulcanizing can, and after vulcanizing the rubber by heating and pressurization, It is common to remove the mold from the mold to obtain a vulcanized belt sleeve. However, when the back surface is made of a rubber layer, the coefficient of friction with the inner mold is higher than when the back surface is made of canvas, so that it is very difficult to remove the vulcanized belt sleeve. Further, if the mold is forcibly removed here, there is a problem that deformation such as turbulence of the core wire or meandering occurs.

  For such problems, for example, it was considered to ensure the demoldability by interposing auxiliary materials such as release paper and taffeta between the inner mold and the unvulcanized stretched rubber sheet. Increased processes and high costs were problems. It was also considered that a mold release agent was applied to the inner mold surface to ensure demoldability. However, a fine mass of the mold release agent present on the mold surface was vaporized and expanded during vulcanization. It was found that minute irregularities were generated on the surface of the vulcanized belt sleeve. Further, it has been found that the V-ribbed belt obtained by these methods has an unstable coefficient of friction on the back surface, and as a result, abnormal noise and vibration are generated when traveling on the back surface.

  The present invention has been made in view of the above problems, and the object of the present invention is to ensure good demoldability without intervening auxiliary materials, and to wear and sound resistance. An object of the present invention is to provide a V-ribbed belt manufacturing method and a V-ribbed belt capable of maintaining a low coefficient of friction at a relatively low level and stably while having excellent performance and sufficient transmission performance.

  That is, according to the first aspect of the present invention, in the method of manufacturing a V-ribbed belt in which a plurality of ribs extending in the longitudinal direction of the belt are provided on the abdominal surface and the back surface is formed of an elastic rubber layer, A step of forming an unvulcanized belt sleeve by placing a stretch rubber layer and a back surface on the inner peripheral side and an abdominal surface on the outer peripheral side, and vulcanizing the unvulcanized belt sleeve to form a flocked layer on the surface. A step of forming a vulcanized belt sleeve is provided.

  The invention according to claim 2 of the present application is the method for producing the V-ribbed belt according to claim 1, wherein a stretched rubber sheet having a flocked layer on the surface is fitted to the inner mold so that the flocked layer is an inner periphery. The elastic rubber layer is arranged on the inner mold through the flocking layer.

  The invention according to claim 3 of the present application is the method for producing the V-ribbed belt according to claim 1, wherein after forming a flocking layer on the surface of the inner mold, the inner mold is fitted with a stretched rubber sheet. A stretch rubber layer is arranged through the flocked layer.

  Invention of Claim 4 of this application is a manufacturing method of the V ribbed belt of Claim 2, Comprising: The expansion | extension rubber sheet which has a flocking layer on the surface is formed by giving electrostatic flocking to a rubber sheet, It is characterized by the above-mentioned. And

  The invention according to claim 5 of the present invention is the method for producing a V-ribbed belt according to any one of claims 1 to 4, wherein the stretched rubber layer contains short fibers, and the short fibers are oriented in the belt width direction. It is arranged so that it may be arranged.

  Invention of Claim 6 of this application is a manufacturing method of the V-ribbed belt of any one of Claims 1-4, Comprising: An extending | stretching rubber layer contains a short fiber in a random orientation state, It is characterized by the above-mentioned.

  The invention according to claim 7 of the present application is a V-ribbed belt characterized in that a plurality of ribs extending in the longitudinal direction of the belt are disposed on the abdominal surface, and the back surface is formed of an elastic rubber layer having a flocking layer.

  The invention according to claim 8 of the present application is the V-ribbed belt according to claim 7, wherein the stretched rubber layer contains short fibers, and the short fibers are oriented in the belt width direction.

  The invention according to claim 9 of the present application is the V-ribbed belt according to claim 7, wherein the stretched rubber layer contains short fibers in a randomly oriented state.

  The invention according to claim 10 of the present application is the V-ribbed belt according to any one of claims 7 to 9, wherein the flocked layer contains nylon short fibers.

  According to the invention described in claim 1, by performing vulcanization by interposing the flock layer between the inner mold and the unvulcanized belt sleeve, the friction coefficient of the surface of the vulcanized belt sleeve is reduced, and the mold release It can be expected that the demoldability of the vulcanized belt sleeve will be improved without the use of additives and auxiliary materials. In addition, the back of the belt is composed of a stretched rubber layer with a flocking layer, so that it has excellent wear resistance and sound resistance, and has sufficient transmission performance, while maintaining a relatively low back friction coefficient. A V-ribbed belt that can be maintained can be easily obtained.

  According to the invention described in claim 2, since the vulcanization is performed using the stretched rubber sheet having the flocked layer on the surface, the flocked layer adheres well in the obtained vulcanized belt sleeve.

  According to the invention described in claim 3, since it can be formed using a normal stretched rubber sheet, there is no trouble of separately preparing a special stretched rubber sheet.

  According to invention of Claim 4, a flocking layer can make a density and uniformity uniform.

  According to the fifth aspect of the present invention, since the back surface is composed of the short fiber-containing rubber compound, it is possible to expect the effect that the adhesive wear is less likely to occur even when the back surface is running, and the tear resistance is excellent. Moreover, there is an advantage that the orientation of the short fibers contained in the stretched rubber layer is set in the belt width direction so that the flexibility of the belt is hardly affected.

  According to the sixth aspect of the present invention, since the back surface is composed of the short fiber-containing rubber compound, it is possible to expect an effect that adhesion wear is less likely to occur even when the back surface is running, and that the tear resistance is excellent. In addition, since it has resistance to forces acting from multiple directions without showing directionality in a certain direction, it is possible to suppress the generation of tears and cracks from multiple directions, thereby producing the effect of improving the belt life. Can do.

  According to the seventh aspect of the present invention, the back surface of the belt is constituted by the stretch rubber layer having the flocking layer, so that it has excellent wear resistance and sound generation resistance, and has sufficient transmission performance, and has a back friction. A V-ribbed belt capable of maintaining the coefficient relatively low and stable can be obtained.

  According to invention of Claim 8, since the back surface is comprised with the short fiber containing rubber compound, it is hard to generate | occur | produce adhesive abrasion also in back surface driving | running, and the effect that it is excellent in tearing resistance can be anticipated. Moreover, there exists an advantage that it is excellent in belt flexibility by making the orientation of the short fiber contained in an extending | stretching rubber layer into a belt width direction.

  According to the ninth aspect of the present invention, since the back surface is composed of the short fiber-containing rubber compound, it is possible to expect the effect that the adhesive wear hardly occurs even during the back surface traveling and the tear resistance is excellent. In addition, since it has resistance to forces acting from multiple directions without showing directionality in a certain direction, it is possible to suppress the generation of tears and cracks from multiple directions, thereby producing the effect of improving the belt life. Can do.

  According to invention of Claim 10, it can be set as the V ribbed belt which was further excellent in abrasion resistance and sound-proofing property by making a flock layer contain a nylon short fiber.

Hereinafter, a method for manufacturing a V-ribbed belt according to the present invention will be described with reference to FIGS.
FIG. 1 is a sectional view showing a state in which an unvulcanized belt sleeve is formed on the inner mold, and FIG. 2 is a sectional view showing a state after the vulcanized belt sleeve is formed.

  First, an unvulcanized stretched rubber sheet having a flocked layer, a core wire serving as a tensile body, an unvulcanized adhesive rubber sheet, and an unvulcanized compressed rubber sheet were sequentially wound endlessly on the outer peripheral surface of the inner mold 21. A flat wide unvulcanized belt sleeve 11 is formed. That is, an unvulcanized stretched rubber sheet having a flocked layer is wound around the inner mold 21 so that the flocked layer becomes an inner peripheral surface, and then the stretched rubber layer 15 is disposed via the flocked layer 14, and then the cord 13 Spin in a spiral. Next, an unvulcanized belt sleeve 11 made of a rubber laminate in which an adhesive rubber layer 12 and a compressed rubber layer 16 are arranged by sequentially winding an unvulcanized adhesive rubber sheet and an unvulcanized compressed rubber sheet, and a tensile body is embedded. Form. The unvulcanized belt sleeve 11 has a back surface on the inner peripheral side in contact with the inner mold and an abdominal surface on the outer peripheral side.

  Next, with the unvulcanized belt sleeve 11 held on the inner mold 21, a jacket 22 is extrapolated to form a mold assembly, and this mold assembly is placed inside a vulcanizing can (not shown). The base 20 is placed and fixed, the lower surface is sealed, and the upper surface is sealed with the inner lid 26. Then, steam is introduced into the outer surface of the mold assembly and the inner mold 21 to unvulcanize the belt sleeve. 11 is heated and pressurized from the inner and outer surfaces and vulcanized.

  After the mold assembly thus vulcanized is taken out of the vulcanizing can and cooled, the vulcanized belt sleeve 11 ′ is removed from the inner mold 21 to obtain a vulcanized belt sleeve 11 ′ having a flocking layer 14. . Next, a rib portion is formed by grinding and polishing a plurality of V-grooves extending in the circumferential direction on the compressed rubber layer 16 of the vulcanized belt sleeve 11 ′, and then the vulcanized belt sleeve 11 ′ is circumferentially disposed. By cutting and reversing to a predetermined width, a plurality of V-ribbed belts having a constant circumferential length and formed with ribs extending in the circumferential direction can be obtained. This V-ribbed belt has a plurality of ribs extending in the longitudinal direction of the belt on the abdominal surface, and the back surface is composed of an extended rubber layer having a flocking layer.

  Here, the unvulcanized stretched rubber sheet having a flocking layer can be produced by forming an adhesive layer on the surface of the unvulcanized rubber sheet and attaching short fibers on the adhesive layer.

  Examples of the method for forming the adhesive layer include a method in which an adhesive is applied by a spray method, a dip method, or the like. Before forming the adhesive layer, the surface may be subjected to a pretreatment such as a cleaning treatment such as alcohol wiping or a primer treatment.

  Examples of the adhesive include resorcin / formaldehyde / latex (RFL) liquid, urethane emulsion, acrylic emulsion, vinyl acetate emulsion, styrene emulsion, rubber adhesive, and organic solvent adhesive. The RFL liquid is obtained by mixing an initial condensate of resorcin and formaldehyde in a latex. Examples of the latex used here include chloroprene, styrene-butadiene-vinylpyridine terpolymer, hydrogenated nitrile, NBR, ethylene. α-olefin / diene copolymer rubber latex. Further, an isocyanate compound can be added to the RFL liquid.

  The thickness of the adhesive layer is not particularly limited, but is 0.05 to 1 mm, preferably 0.05 mm to 0.5 mm.

  The method for attaching the short fibers is not limited to a mechanical or electrostatic method. For example, the short fibers are adhered to the rubber surface by dropping or spraying the short fibers on the rubber sheet on which the adhesive layer is formed, and then natural or heat drying is performed. Also, for example, a short fiber in which a metal mold having a rubber sheet on which an adhesive layer is formed is grounded, an electric field is formed by applying a voltage to an electrode of an electrostatic flocking machine, and the surface is electrodeposited in the electric field , Fly and stick to the rubber surface to attach the short fibers, and then perform natural or heat drying. In consideration of density and uniformity, electrostatic flocking is desirable.

Desired short fiber material is polyamide such as 6 nylon and 66 nylon, aramid such as p-aramid and m-aramid, polyester, vinylon, carbon fiber, polytetrafluoroethylene, cotton, polyparaphenylene benzobisoxazole, etc. It is chosen according to. In particular, it is desirable to include a polyamide short fiber having a high sound-proofing effect. The length of the short fiber is preferably 0.1 to 5.0 mm, more preferably 0.2 to 1.0 mm. The fiber diameter is preferably 0.2 to 1.0 dtex. The aspect ratio (length Lmm / thickness diameter Dmm) is preferably 30 to 300. In addition, the density of short fibers (flocking density) affects the coefficient of friction, its stability, and sound and vibration during travel. The friction coefficient is low and stable, and it can suppress sound and vibration during travel. It is desirable to configure as follows. Although not limited, Preferably it can be set as 3,000-500,000 piece / cm < ² >.

  Instead of forming an adhesive layer on the surface of the rubber sheet and attaching the short fibers, an adhesive containing short fibers may be attached to the surface of the rubber sheet to form a flocking layer.

  As another method for disposing the stretched rubber layer 15 via the flocked layer 14, an inner mold having short fibers attached to the outer peripheral surface is prepared, and an unvulcanized stretched rubber sheet having no flocked layer is used as the inner mold. This can be achieved by stroking. Specifically, after applying a release agent such as silicone oil to the outer peripheral surface of the inner mold, an adhesive layer is formed by the method as described above, and then the short fiber is dropped or sprayed to adhere, or the inner mold The inner mold in which the short fibers are attached to the outer peripheral surface can be prepared by charging the short fibers and applying the short fibers by electric lines of force.

  In the embodiment shown in FIGS. 1 and 2 described above, the adhesive rubber layer 12 exists between the stretched rubber layer 15 and the compressed rubber layer 16, but the adhesive rubber layer 12 is not essential in the present invention. . On the other hand, it is also possible to spin the core wire after the unvulcanized stretched rubber sheet and the unvulcanized adhesive rubber sheet are rubbed in order. It is also possible to spin the core wire after the unvulcanized stretched rubber sheet and the unvulcanized adhesive rubber sheet are sequentially applied, and further to apply the unvulcanized adhesive rubber sheet and the unvulcanized compressed rubber sheet sequentially. .

  If the rubber layer surrounding the core wire contains a short fiber, the adhesion between the core wire and the belt body is difficult. Therefore, one of the rubber layers in contact with the core wire does not contain a short fiber. It is desirable to make up with a composition. Here, in order to suppress the drop of the core wire, it is desirable that the stretched rubber layer contains short fibers. At this time, considering the flexibility of the belt, it is preferable that the short fibers are oriented in the belt width direction. The stretched rubber layer may contain short fibers in a random orientation state. As a result, since it is resistant to forces acting from multiple directions without showing directionality in a certain direction, it is possible to suppress the occurrence of cracks and cracks from multiple directions, thereby improving the belt life. Can play. At this time, the short fiber is preferably a short fiber having a bend.

Further, the apparatus used in the method for producing the V-ribbed belt in the present invention is not limited to the above-described one.
As another embodiment, for example, an inner cylindrical drum equipped with a flexible jacket is prepared, and an unvulcanized stretch rubber sheet, a core wire, an unvulcanized adhesive rubber sheet, and an unvulcanized rubber having a flocking layer on the outer peripheral surface thereof An unvulcanized belt sleeve is formed in which compressed rubber sheets are sequentially rolled endlessly. Next, the unvulcanized belt sleeve is placed and fixed in the outer mold while the sleeve is attached to the inner cylindrical drum, and then the pressurized medium is fed into the flexible jacket to allow The flexible jacket is expanded and the unvulcanized belt sleeve mounted on the outer peripheral surface thereof is uniformly expanded in the radial direction, and brought into contact with a heater or an outer mold heated with high-temperature steam to perform vulcanization. At this time, when a mold having a V projection corresponding to the rib marking is used as the outer mold, the compression rubber layer of the unvulcanized belt sleeve is placed in the V groove of the outer mold by the expansion pressing force of the flexible jacket. It is possible to form a vulcanized belt sleeve that is vulcanized in a state of being sunk into the rib and has rib markings. After vulcanization, the air filled in the flexible jacket is exhausted, and then the flexible jacket is restored to its original position by suction, and the vulcanized belt sleeve is taken out. According to the above manufacturing method, there is an advantage that the rib is accurately engraved in a simple process.

  The production method of the present invention may include a step of flocking the surface of the compressed rubber layer.

  The V-ribbed belt obtained by the manufacturing method as described above is composed of a stretched rubber layer having a plurality of ribs extending in the belt longitudinal direction on the abdominal surface and a back surface having a flocking layer. One embodiment of the V-ribbed belt is shown in FIG. The V-ribbed belt of the present invention, that is, the V-ribbed belt 1 is formed of an elastic rubber layer 5 having a back surface 8 having a flocking layer 4, and a core wire 3 is disposed adjacent to the elastic rubber layer 5 in the belt longitudinal direction. In addition, a part of the core wire 3 is embedded in the stretched rubber layer 5. The adhesive rubber layer 2 is disposed below the stretched rubber layer 5, and the compressed rubber layer 6 containing short fibers (the short fibers are oriented in the belt width direction) is disposed below the stretch rubber layer 5. The compressed rubber layer 6 serving as the abdominal surface is provided with a plurality of rib portions 7 having a substantially triangular cross section extending in the longitudinal direction of the belt.

  FIG. 4 shows another embodiment of the V-ribbed belt. The V-ribbed belt 1 is formed of a stretched rubber layer 5 having a flock layer 4 on the back surface 8, a core wire 3 is disposed adjacent to the stretched rubber layer 5 in the longitudinal direction of the belt, and a part of the core wire 3. Is embedded in the stretched rubber layer 5. The lower layer of the stretched rubber layer 5 has a configuration in which a compressed rubber layer 6 not containing short fibers is disposed. The compressed rubber layer 6 is provided with a plurality of rib portions 7 having a substantially triangular cross section extending in the longitudinal direction of the belt, and the surface thereof has a flocking layer 9.

  FIG. 5 shows still another embodiment of the V-ribbed belt. The V-ribbed belt 1 is formed of a stretched rubber layer 5 having a flock layer 4 on the back surface 8, a core wire 3 is disposed adjacent to the stretched rubber layer 5 in the longitudinal direction of the belt, and a part of the core wire 3. Is embedded in the stretched rubber layer 5. The adhesive rubber layer 2 and the compressed rubber layer 6 containing short fibers (short fibers are oriented along the rib shape) are disposed below the stretched rubber layer 5. The compressed rubber layer 6 is provided with a plurality of rib portions 7 having a substantially triangular cross section extending in the belt longitudinal direction.

  Examples of the rubber used for the compressed rubber layer 6 include ethylene / α-olefin elastomer, nitrile rubber, hydrogenated nitrile rubber, hydrogenated nitrile rubber added with unsaturated carboxylic acid metal salt, chlorosulfonated polyethylene, chloroprene. , Urethane rubber, epichlorohydrin rubber, natural rubber, CSM, ACSM, SBR and the like.

  Hydrogenated nitrile rubber has a hydrogenation rate of 80% or more, and preferably 90% or more in order to exhibit heat resistance and ozone resistance characteristics. Hydrogenated nitrile rubber having a hydrogenation rate of less than 80% has extremely low heat resistance and ozone resistance. Considering oil resistance and cold resistance, the amount of bound acrylonitrile is preferably in the range of 20 to 45%.

  Chlorosulfonated polyethylene has a chlorine content of 15 to 35% by weight, preferably 25 to 32% by weight, and a chlorosulfonated linear chain having a sulfur content in the range of 0.5 to 2.5% by weight. Low density polyethylene.

  Examples of the ethylene / α-olefin elastomer include ethylene / propylene rubber (EPM) and ethylene / propylene / diene monomer (EPDM). Examples of diene monomers include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, cyclooctadiene, and the like.

  A peroxide can be added as a vulcanizing agent for the ethylene / α-olefin elastomer. In addition, as a co-agent, TIAC, TAC, 1,2 polybutadiene, metal salt of unsaturated carboxylic acid, oximes, guanidine, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, NN′-m -Phenylene bismaleimide, sulfur and the like are usually used for peroxide crosslinking.

  Among these, N, N'-m-phenylene dimaleimide is preferable, and by adding this, the degree of crosslinking can be increased to prevent adhesive wear and the like. The addition amount of N, N′-m-phenylene dimaleimide is 0.2 to 10 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin elastomer. The effect of improving wear resistance and adhesive wear resistance is small, and when the amount exceeds 10 parts by weight, the elongation of the vulcanized rubber is remarkably lowered, resulting in a problem in bending resistance.

  Further, by adding 0.01 to 1 part by weight of sulfur to 100 parts by weight of the ethylene / α-olefin elastomer, it is possible to control the decrease in the elongation of the vulcanized rubber. If the amount exceeds 1 part by weight, the degree of crosslinking is not improved to the extent that it can be expected.

  Further, the compressed rubber layer 6 is mixed with short fibers selected from nylon 6, nylon 66, polyester, cotton, aramid, polyparaphenylene benzobisoxazole, etc., to improve the side pressure resistance of the compressed rubber layer 6. At the same time, the surface of the compressed rubber layer 6 that becomes a surface in contact with the pulley can be polished by a grinder to project the short fibers. As a result, the friction coefficient of the surface of the compressed rubber layer 16 is reduced, and there is an effect of reducing noise during belt running. Of these short fibers, aramid short fibers which are rigid, strong and wear-resistant are preferably used.

  In order for the aramid short fibers to sufficiently exhibit the above-described effects, the fiber length of the aramid fibers is 1 to 20 mm, and the addition amount is 1 to 30 parts by weight with respect to 100 parts by weight of the ethylene-α-olefin elastomer. It is. This aramid fiber is an aramid having an aromatic ring in its molecular structure, for example, trade names Conex, Nonex, Kevlar, Technora, Twaron, etc.

  The compressed rubber layer 6 has an ethylene / α-olefin elastomer and a fiber diameter of 1.0 μm or less, preferably 0.05 to 0.8 μm with respect to 100 parts by weight of the ethylene / α-olefin elastomer as a matrix rubber. 1-50 parts by weight, preferably 5-25 parts by weight, may be contained in the fiber content of the short fiber reinforced rubber grafted with the short fibers. When the blending amount of the micro short fiber reinforced rubber is less than 1 part by weight, the wear resistance is not sufficient, and when it exceeds 50 parts by weight, the elongation of the rubber composition is lowered, and the heat resistance and the flex resistance are lowered.

  This micro short fiber reinforced rubber is good as a matrix rubber because the ethylene / α-olefin elastomer constituting it is exactly the same as or similar to the ethylene / α-olefin elastomer of the matrix rubber of the compressed rubber layer 6. To join. For this reason, since the ethylene / α-olefin elastomer and the micro short fiber are chemically bonded between the micro short fiber reinforced rubber and the matrix rubber, or among the micro short fiber reinforced rubber, the compressed rubber layer 6 is not easily cracked. Even if a crack occurs, it is difficult to propagate.

  Further, the compressed rubber layer 6 may include reinforcing agents such as carbon black and silica, fillers such as clay and calcium carbonate, softeners, processing aids, anti-aging agents, and co-crosslinking agents such as TAIC as necessary. Various drugs may be added.

  Further, as shown in FIG. 4, it is also possible to plant short fibers on the surface of the compressed rubber layer of the V-ribbed belt 1 to reduce noise during belt running.

  The core wire 3 can use a twisted cord that has been subjected to an adhesive treatment. Polyester fibers mainly composed of polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene terephthalate (PET) fiber, and ethylene-2,6-naphthalate (PEN) as the fiber material constituting the twisted cord And polyamide fibers such as nylon 66. Considering dimensional stability, hygroscopicity, etc., PET fiber is preferable.

  The stretch rubber layer 5 can use the same matrix rubber and compounding agent as the compression rubber layer described above. When short fibers are included, nylon 6, nylon 66, polyester, cotton, aramid, polyparaphenylene benzobisoxazole, and the like can be used as the short fibers, and those having a fiber length of 1 to 20 mm are preferably used. It has been. The amount added is 1 to 30 parts by weight per 100 parts by weight of rubber. Moreover, the short fiber which has a bending can also be used as a short fiber. The short fiber having bending may be any fiber having one or more bent portions per one short fiber. Specifically, milled fiber can be used. The milled fiber is a short fiber obtained by, for example, pulverizing chopped strands with a mill or the like, and can form a short fiber having an appropriate bent portion by a load during the pulverizing process. The stretch rubber layer 5 may also contain short fibers that do not have a bent portion in addition to short fibers that have a bent portion. For example, polyamide (such as nylon short fiber) can be used as the material, and the fiber length is preferably in the range of 0.1 to 3.0 mm.

  When the adhesive rubber layer 2 is disposed, the same matrix rubber and compounding agent as the compressed rubber layer 4 can be used. However, in order to satisfactorily adhere to the fiber cord which is the core wire, an ethylene-α-olefin elastomer composition by sulfur vulcanization not containing peroxide, a chlorosulfonated polyethylene composition or a hydrogenated nitrile rubber composition, etc. Is preferably used. It is desirable not to mix short fibers.

  As an embodiment of the V-ribbed belt, the adhesive rubber layer 2 is disposed, and the V-ribbed belt (FIGS. 3 and 5) composed of a rubber composition containing short fibers as the compressed rubber layer 6 and the adhesive rubber layer 2 are disposed. Although the V-ribbed belt (FIG. 4) which comprised the rubber composition which does not contain a short fiber as the compression rubber layer 6 and planted the short fiber 9 on the surface was illustrated, it is not limited to this, For example, adhesive rubber The layer 2 is arranged, and the compressed rubber layer 6 is composed of a rubber composition containing a short fiber as a compressed rubber layer 6 and the compressed rubber layer 6 is composed of a rubber composition containing a short fiber, and the flocked layer 9 is formed on the surface. The provided V-ribbed belt also belongs to the technical scope of the present invention.

  Next, a method for manufacturing the V-ribbed belt according to this embodiment and specific examples of the V-ribbed belt will be described.

Examples 1 and 2
As a configuration of the V-ribbed belt, a core wire made of a polyester fiber rope is embedded in the adhesive layer, an extension layer having a flocking layer made of polyamide short fiber is arranged on the upper side, and the belt extends in the belt longitudinal direction below the adhesive layer. A V-ribbed belt (6PK1100 size) in which a compression layer having a rib portion was disposed was manufactured. In addition, the flocking density of Example 1 was about 10,000 / cm < ² >, and the flocking density of Example 2 was about 5,000 / cm < ² >.

  In the manufacture of the V-ribbed belt, first, a stretch rubber sheet having a flock layer is obtained by applying electrostatic flocking to one surface of a stretch rubber sheet using polyamide short fibers (fiber length 0.5 mm, fiber diameter 0.9 dtex). Produced. Next, the stretched rubber sheet was wound around a flat cylindrical mold so that the flocked layer was on the inner peripheral side, and then the adhesive rubber sheet constituting the adhesive layer was wound to spin the core wire. A compressed rubber sheet constituting the compressed rubber layer was arranged to form an unvulcanized belt sleeve, and then a vulcanization jacket was inserted on the compressed rubber sheet. Next, the molding mold was placed in a vulcanizing can and vulcanized to produce a cylindrical vulcanizing belt sleeve. When the vulcanized belt sleeve was removed from the mold, the releasability was good. A rib was formed on the compressed rubber layer of the vulcanized belt sleeve by a grinder, and a V-ribbed belt was manufactured by cutting the molded body into individual belts.

Comparative Example 1
As a configuration of the V-ribbed belt, a V-ribbed belt (6PK1100 size) having the same configuration as that of Example 1 was manufactured except that no flocking layer was provided.

  In the manufacture of the V-ribbed belt, the stretched rubber sheet was wound around a flat cylindrical mold without interposing the flocked layer, and then the adhesive rubber sheet constituting the adhesive layer was wound to spin the core wire. A compressed rubber sheet constituting the compressed rubber layer was arranged to form an unvulcanized belt sleeve, and then a vulcanization jacket was inserted on the compressed rubber sheet. Next, the molding mold was placed in a vulcanizing can and vulcanized to produce a cylindrical vulcanizing belt sleeve. An attempt to remove the vulcanized belt sleeve from the mold was not possible.

Comparative Example 2
As a configuration of the V-ribbed belt, a V-ribbed belt (6PK1100 size) having the same configuration as that of Example 1 was manufactured except that no flocking layer was provided.

  In manufacturing a V-ribbed belt, first, a silicon mold release agent is applied to the surface of a flat cylindrical mold, and then an elastic rubber sheet is wound around the cylindrical mold, and then an adhesive rubber sheet constituting an adhesive layer is wound. Spinning the heart. A compressed rubber sheet constituting the compressed rubber layer was arranged to form an unvulcanized belt sleeve, and then a vulcanization jacket was inserted on the compressed rubber sheet. Next, after putting the molding mold into a vulcanizing can and vulcanizing, the cylindrical vulcanizing belt sleeve was removed from the mold, and the demolding property was good. A rib was formed on the compressed rubber layer of the vulcanized belt sleeve by a grinder, and a V-ribbed belt was manufactured by cutting the molded body into individual belts. In addition, minute irregularities due to bubbles were confirmed on the back surface of the obtained V-ribbed belt.

Comparative Example 3
As a configuration of the V-ribbed belt, a V-ribbed belt (6PK1100 size) having the same configuration as that of Example 1 was manufactured except that no flocking layer was provided.

  In the manufacture of the V-ribbed belt, first, the stretched rubber sheet was wound around the surface of a flat cylindrical mold via a resin film, and then the adhesive rubber sheet constituting the adhesive layer was wound to spin the core wire. A compressed rubber sheet constituting the compressed rubber layer was arranged to form an unvulcanized belt sleeve, and then a vulcanization jacket was inserted on the compressed rubber sheet. Next, after putting the molding mold into a vulcanizing can and vulcanizing, the cylindrical vulcanizing belt sleeve was removed from the mold, and the demolding property was good. After peeling the resin film from the vulcanized belt sleeve, ribs were formed on the compressed rubber layer with a grinder, and V-ribbed belts were manufactured by cutting the molded body into individual belts.

  Here, as the compressed rubber sheets of Examples and Comparative Examples, rubber compositions prepared by blending as shown in Table 1 were kneaded with a Banbury mixer and then rolled with a calendar roll. As the adhesive rubber sheet, a rubber composition prepared by removing short fibers from the composition shown in Table 1 and kneaded with a Banbury mixer and then rolled with a calendar roll was used. As the stretch rubber sheet, a rubber composition prepared by removing short fibers from the formulation shown in Table 1 and kneaded with a Banbury mixer and then rolled with a calender roll was used.

  The back friction characteristics of the V-ribbed belt thus obtained were evaluated. In the friction test, as shown in FIG. 6, the back surface of the V-ribbed belt 19 is wound around the guide roller 17 so that the winding angle is 90 °, the weight 18 of 2.0 kgf is suspended, and the guide roller 17 is rotated at 43 rpm. Then, the tension T1 on the tension side and the tension T2 on the loose side are detected by detecting the value of the load cell. From the tension ratio (T1 / T2), the friction coefficient μ = (1 / 2π) ln (T1 / T2 ) The measurement time was 40 seconds, and the relationship between the elapsed time and the friction coefficient was examined. The results for Example 1 are shown in FIG. 7, and the results for Comparative Example 2 are shown in FIG. In the measurement, the friction coefficient (average of the highest value and the lowest value) in 30 seconds after 10 to 40 seconds elapsed time was obtained. The evaluation is performed at n = 3, and the average value is expressed as a back friction coefficient. The results are shown in Table 2.

  As a result, FIG. 7 and FIG. 8 revealed that Example 1 having a flocked layer on the back surface had a lower coefficient of friction and was stable than Comparative Example 3 having no flocked layer. From the results in Table 2, it was confirmed that the back friction coefficient was lower in the example.

  The V-ribbed belt obtained by the manufacturing method according to the present invention can be mounted on a drive device for automobiles or general industries.

It is sectional drawing which shows the state which formed the unvulcanized belt sleeve in the inner mold | type in the manufacturing method of the V-ribbed belt which concerns on this invention. It is sectional drawing which shows the state which formed the vulcanization belt sleeve with the belt vulcanizer in the manufacturing method of the V-ribbed belt which concerns on this invention. It is sectional drawing of the V-ribbed belt obtained by the manufacturing method which concerns on this invention. It is sectional drawing of another V-ribbed belt obtained by the manufacturing method which concerns on this invention. It is sectional drawing of another V-ribbed belt obtained by the manufacturing method which concerns on this invention. It is a conceptual diagram explaining the test device which measures the back friction coefficient of a V-ribbed belt. It is a figure which shows the relationship between the back friction coefficient of the V-ribbed belt of an Example, and elapsed time. It is a figure which shows the relationship between the back friction coefficient of the V-ribbed belt of a comparative example, and elapsed time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 V ribbed belt 2 Adhesive rubber layer 3 Core wire 4 Flocking layer 5 Stretch rubber layer 6 Compression rubber layer 7 Rib part 8 Back surface 9 Flocking layer 12 Adhesive rubber layer 13 Core wire 14 Flocking layer 15 Stretch rubber layer 16 Compression rubber layer 21 Inner type

Claims (10)

In the method for producing a V-ribbed belt, in which a plurality of ribs extending in the belt longitudinal direction are disposed on the abdominal surface, and the back surface is constituted by an elastic rubber layer,
A step of forming an unvulcanized belt sleeve by placing an elastic rubber layer on the inner mold through a flocking layer, and a back surface on the inner peripheral side and an abdominal surface on the outer peripheral side, and vulcanizing the unvulcanized belt sleeve A method for producing a V-ribbed belt, comprising a step of forming a vulcanized belt sleeve having a flocked layer on the surface.   2. The V-ribbed belt according to claim 1, wherein a stretched rubber sheet having a flocked layer on the surface is fitted to the inner mold so that the flocked layer is an inner circumference, and the stretched rubber layer is disposed on the inner mold via the flocked layer. Manufacturing method.   The method for producing a V-ribbed belt according to claim 1, wherein after forming the flocked layer on the inner mold surface, the stretched rubber sheet is disposed on the inner mold by mounting a stretched rubber sheet on the inner mold.   The method for producing a V-ribbed belt according to claim 2, wherein the stretched rubber sheet having a flocking layer on the surface is formed by applying electrostatic flocking to the rubber sheet.   The method for producing a V-ribbed belt according to any one of claims 1 to 4, wherein the stretched rubber layer contains short fibers and is arranged so that the short fibers are oriented in the belt width direction.   The method for producing a V-ribbed belt according to any one of claims 1 to 4, wherein the stretched rubber layer contains short fibers in a randomly oriented state.   A V-ribbed belt comprising a plurality of ribs extending in the longitudinal direction of the belt on the abdominal surface and a back rubber surface formed of a stretch rubber layer having a flocking layer.   The V-ribbed belt according to claim 7, wherein the stretched rubber layer contains short fibers, and the short fibers are oriented in the belt width direction.   The V-ribbed belt according to claim 7, wherein the stretched rubber layer contains short fibers in a randomly oriented state. The V-ribbed belt according to any one of claims 7 to 9, wherein the flocking layer contains nylon short fibers.

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