WO2018174093A1

WO2018174093A1 - Friction transmission belt and method for producing same

Info

Publication number: WO2018174093A1
Application number: PCT/JP2018/011189
Authority: WO
Inventors: 田村　貴史; 博樹武市; 長谷川　新
Original assignee: 三ツ星ベルト株式会社
Priority date: 2017-03-21
Filing date: 2018-03-20
Publication date: 2018-09-27

Abstract

The present invention provides a friction transmission belt which is provided with: an extension layer (5) which forms the back surface of the belt; a compressed rubber layer (2) which is formed on one surface of the extension layer and is in contact with pulleys so as to be frictionally engaged with the pulleys; and a core wire (1) which is embedded between the extension layer and the compressed rubber layer in the longitudinal direction of the belt. The compressed rubber layer has a surface that comes into contact with the pulleys; at least a part of the surface is covered with a fiber layer with a fiber resin mixed layer being interposed therebetween; the fiber resin mixed layer contains a resin component and heat-resistant fibers which have a softening point or melting point higher than the vulcanization temperature of a rubber that constitutes the compressed rubber layer; and the fiber layer contains hydrophilic heat-resistant fibers which have a softening point or melting point higher than the above-mentioned vulcanization temperature, but does not contain a resin component.

Description

Friction transmission belt and manufacturing method thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction transmission belt used for driving an automobile engine auxiliary machine and a method for manufacturing the same, and more particularly to a V-ribbed belt in which abnormal noise is suppressed even when wet and a method for manufacturing the same.

Even in the rubber industry field, high performance and high performance are desired for automotive parts. Among such rubber products used for automobile parts, there is a transmission belt, which is widely used for power transmission for driving auxiliary equipment such as an air compressor and an alternator of an automobile. In recent years, there has been a strict demand for quietness. In particular, in a drive device for automobiles, since sounds other than engine noise are abnormal noises, countermeasures against belt sounding are required.

In Patent Document 1, an ethylene-α-olefin elastomer-based elastomer tooth is covered with a barrier layer made of a thermoplastic material, and the barrier layer is covered with an outer cover formed of a woven fabric or a nonwoven fabric, and A transmission belt is disclosed in which the outer cover at least on the flank of the elastomeric teeth is partially included within a portion of the thickness of the barrier layer. In this document, the barrier layer suppresses the passage of dental rubber (the raw material constituting the elastomer tooth) during belt molding to the outer cover, and the outer cover (fiber or It is described that the generation of noise can be avoided by partially embedding the yarn) to improve the crack resistance of the barrier layer and projecting (exposing) the remaining portion not embedded to the pulley side. . In addition, the barrier layer and the outer cover are integrated in advance by calendering and rolling, and the non-woven fiber constituting the outer cover penetrates only partially into the film constituting the barrier layer and is in a raw state It is described that it is possible to never penetrate into the dental rubber that progresses to the vulcanized state. Furthermore, it is described that a woven fabric or nonwoven fabric based on polyethylene is particularly suitable as the woven fabric or nonwoven fabric forming the outer cover.

However, with this drive belt, the outer cover is only partially embedded within a portion of the thickness of the barrier layer, and as wear progresses as the belt travels, the outer cover eventually becomes Since only the non-existing barrier layer is exposed, there is a possibility that the crack resistance and wear resistance of the barrier layer may be lowered. In such a state, since the barrier layer is not reinforced by the outer cover, the barrier layer may be peeled off from the surface of the elastomer tooth due to shear from the pulley, or the inside of the barrier layer may be broken. There is also sex. In addition, this drive belt uses a peroxide to cure dental rubber or other chemicals with curing ability to promote the bonding between the teeth and the barrier layer, but only chemical action. However, it is not sufficient to suppress the peeling of the barrier layer, and has no effect on the destruction of the barrier layer.

On the other hand, in Patent Document 2, as a friction transmission belt capable of improving sound resistance and wear resistance, a stretch layer that forms the back surface of the belt, and one surface of the stretch layer are formed on the side surface. A friction transmission belt comprising: a compression rubber layer that is in frictional engagement with a pulley; and a core wire that is embedded along the longitudinal direction of the belt between the extension layer and the compression rubber layer, the compression rubber At least a part of the surface in contact with the pulley of the layer is coated with a fiber resin mixed layer in which a resin component and a heat-resistant fiber having a softening point or a melting point exceeding the vulcanization temperature are mixed, and the heat-resistant fiber is the fiber A friction transmission belt including fibers embedded from a resin mixed layer to the compressed rubber layer is disclosed.

However, even with this friction transmission belt, depending on the mode of use and the length of use, it is not sufficient to meet the recent demands for quietness in the automobile industry. Was not enough.

Japanese Laid-Open Patent Publication No. 2010-101489 Japanese Unexamined Patent Publication No. 2014-111981

Therefore, an object of the present invention is to provide a friction transmission belt capable of improving sound resistance when wet and a manufacturing method thereof.

Another object of the present invention is to provide a friction transmission belt capable of improving sound resistance and wear resistance over a long period of time and a method for manufacturing the same.

As a result of intensive studies to achieve the above-mentioned problems, the present inventors have coated at least a part of the surface of the friction transmission belt that is in contact with the pulley of the compression rubber layer with a fiber layer through a fiber resin mixed layer, and the fibers The resin mixed layer is configured to include a resin component and a heat-resistant fiber having a softening point or a melting point exceeding the vulcanization temperature of the rubber forming the compressed rubber layer, and the fiber layer has a softening point exceeding the vulcanization temperature or The present invention has been completed by finding that the composition can be improved by including a hydrophilic heat-resistant fiber having a melting point and a fiber layer that does not contain a resin component, so that the sound-proofing property when wet can be improved.

That is, the friction transmission belt of the present invention includes a stretch layer that forms the back surface of the belt, a compression rubber layer that is formed on one surface of the stretch layer and frictionally engages with the pulley, the stretch layer, and the compression layer. A friction transmission belt having a core wire embedded along the longitudinal direction of the belt between the rubber layer, wherein the compression rubber layer has a surface in contact with the pulley, and at least a part of the surface is a fiber resin. The fiber resin mixed layer is covered with a fiber layer through a mixed layer, and the fiber resin mixed layer includes a resin component and a heat-resistant fiber having a softening point or a melting point exceeding a vulcanization temperature of rubber forming the compressed rubber layer, The fiber layer contains hydrophilic heat-resistant fibers having a softening point or melting point exceeding the vulcanization temperature, and does not contain a resin component. The heat-resistant fiber may include a fiber embedded from the fiber resin mixed layer to the compressed rubber layer. The resin component (resin component contained in the fiber resin mixed layer) may be a thermoplastic resin (particularly, a polypropylene resin) that can be melted or softened at the vulcanization temperature. The hydrophilic heat resistant fiber may be a cellulosic fiber. The heat-resistant fiber may be a cellulosic fiber. A fiber component (fiber component) that is the sum of the resin component (resin component) contained in the fiber resin mixed layer, the heat resistant fiber contained in the fiber resin mixed layer, and the hydrophilic heat resistant fiber contained in the fiber layer. )) May be approximately resin component / fiber component = 50/50 to 20/80. The friction transmission belt of the present invention may be a V-ribbed belt in which the compressed rubber layer has a plurality of ribs extending in parallel with each other in the belt longitudinal direction.

In the present invention, on a cylindrical drum, a sheet for forming the stretch layer, the core wire, an unvulcanized rubber sheet for forming the compressed rubber layer, the fiber resin mixed layer, and the fiber A winding step of sequentially winding sheet-like structures for forming layers to obtain a laminated sheet, and a vulcanization molding step of vulcanizing and molding the unvulcanized rubber sheet by pressing the laminated sheet against a mold A method of manufacturing a friction transmission belt is also included, wherein the vulcanization molding step pre-heats the unvulcanized rubber sheet at a temperature lower than the vulcanization temperature and then vulcanizes the unvulcanized rubber sheet. . In the winding step, as the sheet-like structure, a non-woven fabric (1) containing a first thermoplastic resin having a softening point or melting point equal to or lower than the vulcanization temperature, a non-woven fabric (2) containing the heat-resistant fiber, and softening The nonwoven fabric (3) containing the second thermoplastic resin having a point or melting point not higher than the vulcanization temperature and the nonwoven fabric (4) containing the hydrophilic heat-resistant fiber may be wound in this order, or the softening point or A laminated nonwoven fabric of a first nonwoven fabric containing a thermoplastic resin having a melting point equal to or lower than the vulcanization temperature and a second nonwoven fabric containing the hydrophilic heat-resistant fiber may be wound twice with the first nonwoven fabric inside. . The basis weight of the sheet-like structure may be about 50 to 150 g / m ² .

In the present invention, at least a part of the surface of the friction transmission belt that is in contact with the pulley of the compressed rubber layer is covered with a fiber layer via a fiber resin mixed layer, and the fiber resin mixed layer includes the resin component and the compressed rubber layer. A heat-resistant fiber having a softening point or a melting point exceeding the vulcanization temperature of the rubber forming the rubber, the fiber layer includes a hydrophilic heat-resistant fiber having a softening point or a melting point exceeding the vulcanization temperature, and a resin component Therefore, it is possible to improve sound resistance when wet. In addition, sound resistance and wear resistance can be improved over a long period of time.

FIG. 1 is a schematic cross-sectional view showing an example of a V-ribbed belt. FIG. 2 is a schematic diagram for explaining an example of a method for producing a friction transmission belt according to the present invention. FIG. 3 is a schematic diagram showing a layout of a friction coefficient measurement test during normal running in the example. FIG. 4 is a schematic diagram illustrating a layout of a friction coefficient measurement test during water injection in the example. FIG. 5 is a schematic diagram showing a layout of a misalignment pronunciation test in the embodiment. FIG. 6 is a schematic diagram showing a layout of a wear test in the example. FIG. 7 is a schematic diagram showing a layout of a durability running test in the example. FIG. 8 is a scanning electron micrograph of the rib cross section of the V-ribbed belt obtained in Example 2.

[Friction transmission belt]
The friction transmission belt of the present invention includes a stretch layer that forms a belt back surface, a compression rubber layer that is formed on one surface of the stretch layer and that frictionally engages with a pulley, the stretch layer, and the compression rubber layer And a core wire embedded along the longitudinal direction of the belt. The compressed rubber layer has a surface in contact with the pulley, and at least a part of the surface is covered with a fiber layer via a fiber resin mixed layer. The fiber-resin mixed layer includes a resin component and a heat-resistant fiber having a softening point or a melting point exceeding the vulcanization temperature of the rubber forming the compressed rubber layer. The fiber layer contains hydrophilic heat-resistant fibers having a softening point or melting point exceeding the vulcanization temperature, and does not contain a resin component. In the present invention, at least a part of the outermost surface (friction transmission surface) in contact with the pulley of the compressed rubber layer is covered with a fiber layer containing hydrophilic heat-resistant fibers, so that the sound resistance when wet is improved.

In the friction transmission belt of the present invention, an adhesive layer may be provided between the compression rubber layer and the extension layer as necessary in order to improve the adhesion between the core wire and the extension layer or the compression rubber layer. As a form which provides an adhesive layer, the form which embeds a core wire may be sufficient, and the form which embeds a core wire between a compression rubber layer and an adhesive layer or an adhesive layer and an expansion | extension layer may be sufficient.

Examples of the friction transmission belt include various friction transmission belts such as a V-ribbed belt, a low-edge V belt, and a flat belt. Among these, a V-ribbed belt and a V-belt are preferable, and a V-ribbed belt in which sound generation due to moisture is a problem is particularly preferable.

FIG. 1 is a schematic cross-sectional view showing an example of a V-ribbed belt, which is a schematic cross-sectional view cut in the belt width direction.

In this example, the V-ribbed belt is composed of a compressed rubber layer 2 having a plurality of rib portions 3, an adhesive layer 6, a core wire 1, and a rubber composition in order from the belt lower surface (inner peripheral surface) to the belt upper surface (back surface). The formed stretch layer 5 is laminated, and the compressed rubber layer 2 has a short fiber 4 in a flow state along the shape of the rib portion (in the vicinity of the surface of the rib portion, the short fiber 4 has the rib portion 3). In a state of being aligned along the outer shape. The compressed rubber layer 2 has rib portions 3 (in FIG. 1, the number of ribs is 3) extending in a plurality of rows along the longitudinal direction of the belt on the inner peripheral surface of the belt body. The cross-sectional shape in the direction orthogonal to the longitudinal direction becomes smaller in width from the belt outer peripheral side (the side that does not have a rib portion and does not frictionally engage with the pulley) toward the inner peripheral side (taperes toward the tip). ) Inverted trapezoidal shape (V-shaped cross section). The core wire 1 is embedded in the main body along the longitudinal direction of the belt. A part of the core wire 1 is in contact with the stretch layer 5 and the remaining part is in contact with the adhesive layer 6. Further, the compressed rubber layer 2 is at least partly in contact with the pulley (the friction transmission surface of the rib portion 3) is covered with a fiber resin mixed layer and a fiber layer (not shown).

(Fiber resin mixed layer)
The fiber resin mixed layer may be formed on at least a part of the friction transmission surface in contact with the pulley of the compressed rubber layer, but is usually formed on the entire surface of the compressed rubber layer from the viewpoint of productivity. In the fiber-resin mixed layer, a resin component and a heat-resistant fiber having a softening point or a melting point exceeding the vulcanization temperature of the rubber forming the compressed rubber layer (hereinafter sometimes simply referred to as vulcanization temperature) are mixed. ing. Therefore, the friction transmission surface can be reinforced by interposing the fiber resin mixed layer between the compressed rubber layer and the fiber layer. Furthermore, at least some of the heat-resistant fibers in the fiber resin mixed layer are embedded from the fiber resin mixed layer to the vicinity of the surface inside the compressed rubber layer (near the interface with the fiber resin mixed layer). It is preferable. By including such heat-resistant fibers embedded across two layers, the portion embedded in the compressed rubber layer plays the role of an anchor effect, and the interface between the fiber resin mixed layer and the compressed rubber layer surface layer can be more firmly bonded. Further, peeling (peeling) of the fiber resin mixed layer from the compressed rubber layer can be prevented. In addition, even if the wear of the fiber layer and the fiber resin mixed layer proceeds and the surface of the compressed rubber layer is exposed, the heat-resistant fiber embedded in the compressed rubber layer is exposed from the inside due to wear, and the vicinity of the interface of the compressed rubber layer Therefore, even if the belt is run for a long time, the wear resistance of the compressed rubber layer (friction transmission surface) can be maintained. The mode of embedding the heat resistant fiber in the compressed rubber layer is the same as the mode of embedding the heat resistant fiber (heat resistant fiber) in the vicinity of the surface of the compressed rubber layer in Patent Document 2, for example.

Of the heat-resistant fibers that are at least partially embedded near the interface inside the compressed rubber layer, at least some of the heat-resistant fibers may be embedded near the interface inside the compressed rubber layer with the resin component attached. Good. Since the friction transmission film of the present invention is obtained by the production method described later, the resin component tends to adhere to the surface of the heat-resistant fiber when the heat-resistant fiber is embedded in the vicinity of the interface inside the compressed rubber layer at the time of rib formation. When the resin component adheres to the surface of the heat-resistant fiber embedded in the compressed rubber layer, the heat-resistant fiber and a member (for example, a rubber composition) that forms the compressed rubber layer can be firmly bonded via the resin component. That is, since the adhesiveness (adhesiveness) between the two can be improved, it is possible to prevent the heat-resistant fibers from dropping (disconnecting) and more reliably prevent the fiber resin mixed layer from peeling from the surface of the compressed rubber layer. Furthermore, since the heat-resistant fibers are firmly fixed to the compressed rubber layer, even if the fiber resin mixed layer is worn away due to the progress of wear, the heat-resistant fibers are prevented from falling off from the vicinity of the interface inside the compressed rubber layer, so The wear resistance and sound resistance of the rubber layer (friction transmission surface) can be maintained over a longer period.

Depth of heat-resistant fibers embedded in the compressed rubber layer (thickness of the fiber rubber mixed layer formed by layering heat-resistant fibers in the vicinity of the interface of the compressed rubber layer) is near the interface inside the compressed rubber layer. For example, 5 to 150 μm, preferably 10 to 120 μm (for example, 30 to 100 μm), and more preferably 50 to 50 μm from the viewpoint of preventing the fiber resin mixed layer from peeling off the surface of the compressed rubber layer. It is about 90 μm (especially 70 to 80 μm). If the embedment depth of the heat-resistant fiber is too shallow, the heat-resistant fiber is likely to fall off, and there is a possibility that peeling of the fiber resin mixed layer from the surface of the compressed rubber layer may not be sufficiently prevented. If the belt is too deep, the thickness of the heat-resistant fibers will be increased, so that when the belt is subjected to reverse bending from the pulley and the rib is stretched, the rib surface is liable to crack and the life of the belt may be shortened. is there. In the friction transmission belt of the present invention, it is preferable that the fiber rubber mixed layer is embedded with a substantially uniform thickness in the vicinity of the interface of the compressed rubber layer.

The average thickness of the fiber resin mixed layer is, for example, about 10 to 300 μm, preferably about 30 to 250 μm, more preferably about 50 to 200 μm (particularly about 70 to 150 μm). If the fiber resin mixed layer is too thin, the crack resistance and wear resistance may be reduced. If it is too thick, the flexibility of the fiber resin mixed layer may be reduced.

In addition, in this specification, the embedding depth of the fiber and the thickness of the fiber resin mixed layer can be measured based on a scanning electron microscope (SEM) photograph, and are obtained as an average value of any five or more locations. The details can be measured by the method described in Examples described later.

(1) Heat-resistant fiber The heat-resistant fiber may contain a long fiber or a fiber formed of a long fiber alone, but preferably contains at least a short fiber. Furthermore, the heat resistant fiber may include different types of heat resistant fibers (multiple types of heat resistant fibers).

As heat-resistant fibers, a fiber shape is imparted even after vulcanization of the rubber forming the compressed rubber layer, and in order to impart various functions to the belt, the vulcanization temperature (for example, about 150 to 200 ° C., particularly about 170 ° C.) is exceeded. What is necessary is just to have a softening point or melting | fusing point, and various synthetic fiber and inorganic fiber can be utilized. The softening point or melting point (or decomposition point) of the heat-resistant fiber may be, for example, T + 10 ° C. or higher when the vulcanization temperature is T, for example, (T + 10) to (T + 400) ° C., preferably (T + 20) to It is (T + 370) ° C., more preferably about (T + 20) to (T + 350) ° C. Since the heat resistant fiber has a softening point or melting point higher than the vulcanization temperature, it maintains a fibrous form even after vulcanization of the rubber forming the compressed rubber layer, and has a desired performance (heat resistant fiber on the friction transmission surface). Can be applied).

Examples of heat-resistant fibers include heat-resistant fibers conventionally used in friction transmission belts, such as natural fibers (cellulosic fibers, wool, silk, etc.); synthetic fibers [aliphatic polyamide fibers (polyamide 6, polyamide 66, polyamide 46 fibers). Polyester fiber (polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate fiber and other poly C _2-4 alkylene C _6-14 arylate fiber), fluorine fiber (polytetrafluoroethylene fiber, etc.), polyacrylic fiber ( Polyacrylonitrile fiber, etc.), polyvinyl alcohol fiber, polyphenylene sulfide (PPS) fiber, poly-p-phenylenebenzobisoxazole (PBO) fiber, aromatic polyamide fiber (p-aramid, m-aramid fiber, etc.)]; inorganic fibers (Carbon fibers, glass fibers, etc.) and the like.

These heat resistant fibers can be used alone or in combination of two or more. When combining two or more types of heat-resistant fibers, the fiber resin mixed layer may have a single layer structure in which different types of heat-resistant fibers are homogeneously mixed, or may have a plurality of laminated structures in which different heat-resistant fibers are laminated. Good. Among these, from the viewpoint of productivity and the like, the fiber resin mixed layer is preferably a single layer, and particularly preferably a single layer formed of the same kind of heat-resistant fibers.

Of these heat-resistant fibers, hydrophilic heat-resistant fibers having a high affinity (water absorption) with water are preferable, and cellulosic fibers are particularly preferable, since the sound-proof property when wet is improved even when the fiber layer is worn. preferable.

Cellulosic fibers include cellulose fibers (cellulose fibers derived from plants, animals, bacteria, etc.) and fibers of cellulose derivatives. Cellulose fibers include, for example, wood pulp (coniferous, hardwood pulp, etc.), bamboo fiber, sugarcane fiber, seed hair fiber (cotton fiber (cotton linter), kapok, etc.), gin leather fiber (hemp, kozo, mitsumata, etc.), Examples thereof include cellulose fibers (pulp fibers) derived from natural plants such as leaf fibers (manila hemp, New Zealand hemp, etc.); cellulose fibers derived from animals such as squirt cellulose; bacterial cellulose fibers; Examples of the cellulose derivative fiber include cellulose ester fiber; regenerated cellulose fiber (rayon, cupra, lyocell, etc.) and the like. Among these cellulosic fibers, cellulose fibers are preferable and pulp is particularly preferable because of excellent balance between water absorption and abrasion resistance.

The fiber form of the heat-resistant fiber is not particularly limited, and may be any form of monofilament, multifilament, spun yarn (spun yarn), or a combination thereof.

The heat resistant fiber may be either a short fiber or a long fiber, but preferably contains at least a short fiber. The average length of the short fibers is, for example, about 1 to 500 mm, preferably about 2 to 300 mm, more preferably about 3 to 200 mm (particularly about 5 to 100 mm). If the fiber length of the short fiber is too short, the reinforcing effect of the friction transmission surface may be lowered, and if it is too long, it may be difficult to make the fiber exist at the interface with the compressed rubber layer. On the other hand, the average length of the long fibers only needs to exceed 500 mm, for example, about 501 mm or more, preferably about 1 to 1500 m, more preferably about 1 to 1000 m (particularly about 1 to 500 m).

Furthermore, short fibers and long fibers may be combined in order to adjust the embedding depth of heat resistant fibers in the compressed rubber layer. When blending long fibers, it is easy to wrap the nonwoven fabric during belt production, and long fibers can be arranged along the longitudinal direction of the belt from the point of being able to form an appropriate rib shape even for fibers with small elongation. preferable. The proportion of long fibers may be 70% by mass or less in the heat-resistant fiber, preferably 50% by mass or less, more preferably 30% by mass or less (for example, about 1 to 10% by mass). If the ratio of long fibers is too large, it may be difficult to cause fibers to exist at the interface with the compressed rubber layer.

The average fiber diameter of the heat resistant fiber is, for example, about 5 to 50 μm, preferably 7 to 40 μm, and more preferably about 10 to 35 μm.

The form of the heat-resistant fiber in the fiber-resin mixed layer (form of the fiber assembly) can be appropriately selected according to the length of the fiber, and may be a woven fabric structure or a knitted fabric structure. And has a non-woven structure (non-woven fiber structure).

The heat-resistant fiber may be subjected to adhesion treatment at the raw material stage for the purpose of improving the adhesion with the compressed rubber layer. As such an adhesion treatment, the heat-resistant fiber is immersed in a resin-based treatment solution in which an epoxy or isocyanate compound is dissolved in an organic solvent (toluene, xylene, methyl ethyl ketone, etc.), or a resorcin-formalin-latex solution (RFL solution). A dipping process may be performed in a processing solution such as. Also, for the purpose of providing adhesion between the heat-resistant fiber and the member forming the compressed rubber layer and / or imparting the performance of the friction transmission surface, for example, the rubber composition is dissolved in the organic solvent to form a rubber paste, and the rubber paste is heat-resistant. A fiber raw material (nonwoven fabric or the like) may be dipped to impregnate and adhere the rubber composition to the heat resistant fiber. These processes can be performed alone or in combination, and the number of processes and the order of processes are not particularly limited, and can be performed as appropriate.

(2) Resin component As a resin component, it melts at a vulcanization temperature to express a role as a binder for the fiber, forms a fiber resin mixed layer, and also on the surface of the fiber embedded in the compressed rubber layer It is preferable that it adheres and the adhesiveness of a fiber resin mixed layer and a compression rubber layer can be improved. Usually, a thermoplastic resin that can be melted or softened at the vulcanization temperature is used, but a thermosetting resin that can be melted or softened at the vulcanization temperature may be used.

The resin component is not particularly limited as long as the melting point (or softening point) is not higher than the vulcanization temperature (for example, about 150 to 200 ° C., particularly about 170 ° C.), but it retains an appropriate viscosity during vulcanization and has an appropriate thickness. The melting point is, for example, (T-50) ° C. to (T + 10) ° C., preferably (T-30) ° C. to (T + 5) ° C., more preferably, when the vulcanization temperature is T. Is about (T-10) ° C. to T ° C. When the melting point is in the vicinity of the vulcanization temperature, the resin component melts with an appropriate viscosity when vulcanizing the rubber forming the compressed rubber layer, and after vulcanization, it contains a part of the hydrophilic heat-resistant fiber. Can solidify. A specific melting point is, for example, about 150 to 180 ° C., preferably about 160 to 175 ° C., and more preferably about 165 to 170 ° C. If the melting point is too high, it may be difficult to form a homogeneous fiber-resin mixed layer. Conversely, if it is too low, the viscosity will decrease too much during vulcanization, impregnating the fiber layer surface, There is a risk that it may be difficult to form a fiber layer having an appropriate thickness.

As long as the resin component has the melting point, the material is not particularly limited, but from the viewpoint of handleability and versatility, an olefin resin such as a polyethylene resin or a polypropylene resin is preferable, and an appropriate amount is obtained during vulcanization. Polypropylene resin is particularly preferable because it retains viscosity and easily forms a fiber layer having an appropriate thickness.

Examples of the polypropylene resin include polypropylene, copolymers of monomers copolymerizable with propylene (binary copolymers such as propylene-ethylene copolymer, propylene- (meth) acrylic acid copolymer; propylene- Terpolymers such as ethylene-butene-1). These polypropylene resins can be used alone or in combination of two or more. Of these polypropylene resins, propylene homopolymers such as polypropylene are preferred.

Of these, polypropylene resins such as polypropylene are particularly preferable because they are easily melted at the vulcanization temperature and have excellent moderate heat resistance.

The shape of the resin component is not particularly limited as long as it fills the gap between the fibers and is attached to the surface of the fiber, but as described later, when a fibrous raw resin is used, Even in a thermoplastic resin having a melting point (or softening point) below the vulcanization temperature, a part of the fiber shape may remain. In the present invention, using a fibrous resin having a melting point (or softening point) equal to or lower than the vulcanization temperature as a raw material, a component in which the fiber shape partially remains is classified as a resin component, not a heat-resistant fiber.

The resin component may be subjected to the same adhesion treatment (or surface treatment) as the heat resistant fiber.

The ratio (mass ratio) between the resin component and the heat-resistant fiber can be selected, for example, from the range of resin component / heat-resistant fiber = 99/1 to 1/99, for example, 95/5 to 5/95, preferably 85/15. It is about 15/85, more preferably about 75/25 to 25/75 (especially 70/30 to 30/70). By combining the resin component and the heat-resistant fiber at such a ratio, the surface of the compressed rubber layer is covered with the fiber-resin mixed layer, and at least a part of the heat-resistant fiber is placed in the vicinity of the surface of the compressed rubber layer from the fiber-resin mixed layer. Can be buried.

(3) Other additives The fiber-resin mixed layer may be a conventional additive, for example, a surfactant, an enhancer, a filler, a metal oxide, a plasticizer, a processing agent or a processing aid, and coloring, as necessary. Agents, coupling agents, stabilizers (ultraviolet absorbers, antioxidants, ozone degradation inhibitors, heat stabilizers, etc.), lubricants, flame retardants, antistatic agents, and the like. Of these, HLB (Hydrophilic−) is improved in that the wettability with water in the fiber layer is improved by bleeding out, thereby improving the water sweeping by the hydrophilic heat-resistant fiber and the water absorption (hydrophilicity) of the rib surface. It may contain a surfactant having a hydrophobic balance of 5 to 15 (especially 7 to 15). The ratio of the additive is 0.1 to 50% by mass, preferably 0.5 to 30% by mass, more preferably 1 to 20% by mass (particularly 1.5 to 10% by mass) with respect to the entire fiber resin mixed layer. )

(Fiber layer)
The fiber layer covers the outermost surface of the compressed rubber layer, includes hydrophilic heat-resistant fibers having a softening point or melting point exceeding the vulcanization temperature, and does not include a resin component. Therefore, since it is flexible and excellent in water absorption, it is possible to improve sound resistance when wet. In the present invention, the reason why the sound resistance when wet is remarkably improved is that water entering between the belt and the pulley can be quickly absorbed by the presence of the fiber layer located on the outermost surface. By suppressing the generation of the film, it can be estimated that the difference between the friction coefficient during normal running (DRY) and the friction coefficient during water injection running (WET) is reduced.

As the hydrophilic heat-resistant fibers contained in the fiber layer, the hydrophilic heat-resistant fibers exemplified as the heat-resistant fibers contained in the fiber resin mixed layer can be used, and cellulosic fibers can be preferably used. As the cellulosic fibers, cellulosic fibers contained in the fiber resin mixed layer can be used, and cellulose fibers (particularly pulp) can be preferably used. The fiber form and average length of the heat-resistant fiber are the same as those of the heat-resistant fiber contained in the fiber resin mixed layer.

The form of the fiber layer (the structure of the fiber assembly) can be appropriately selected according to the length of the fiber, and may be a woven fabric structure or a knitted fabric structure. Woven fiber structure).

The fiber layer is preferably intertwined with and integrated with the fiber resin mixed layer, and in particular, the remainder (unimpregnated) in which a part of a nonwoven fabric having a previously integrated nonwoven fiber structure is impregnated with a resin component. Part) is particularly preferred.

Since the fiber layer does not contain a resin component, it is excellent in flexibility and porosity. If it is a range which does not impair such a characteristic, the other additive illustrated by the fiber resin mixed layer may be included. The ratio of other additives is the same as that of the fiber resin mixed layer.

The average thickness of the fiber layer is, for example, about 10 to 300 μm, preferably about 30 to 250 μm, more preferably about 50 to 200 μm (particularly about 70 to 150 μm). The average thickness of the fiber layer is, for example, about 0.1 to 5 times, preferably about 0.5 to 3 times, and more preferably about 1 to 2 times the average thickness of the fiber resin mixed layer. If the fiber layer is too thin, water absorption and wear resistance may be reduced. If it is too thick, shape defects may occur during belt production.

The porosity of the fiber layer is, for example, about 50 to 98%, preferably about 60 to 97%, more preferably about 75 to 95% (particularly about 80 to 90%).

Resin component (resin component contained in fiber resin mixed layer) and fiber component (heat resistant fiber contained in fiber resin mixed layer and hydrophilic heat resistant fiber contained in fiber layer) contained in both layers of fiber resin mixed layer and fiber layer The resin component / fiber component = 70/30 to 10/90, preferably 50/50 to 20/80, more preferably 40/60 to 25/75 (particularly 35/65 to 25). / 75) grade. Further, in applications that require high sound resistance when wet, resin component / fiber component = 40/60 to 10/90, preferably 35/65 to 15/85, more preferably 30/70 to 20 / 80 may be sufficient. When the ratio of the resin component is too small, the heat-resistant fibers are not sufficiently fixed, and the heat-resistant fibers may be scattered early. On the other hand, if the amount is too large, the water absorption is lowered, and the sound resistance may be lowered.

As described above, the friction transmission belt having the fiber layer on the outermost surface of the compression rubber layer has a small difference between the friction coefficient during normal driving (DRY) and the friction coefficient during water injection (WET). Can prevent stick-slip and improve sound resistance when wet. The difference between the friction coefficient of DRY and the friction coefficient of WET (DRY−WET) may be 0.3 or less, preferably 0.2 or less, more preferably 0.1 or less. In addition, in this specification and a claim, the said friction coefficient is measured by the method as described in the Example mentioned later.

(Compressed rubber layer)
The compressed rubber layer can be appropriately selected according to the type of belt, and for example, a rubber composition or a polyurethane resin composition containing a rubber component and a vulcanizing agent or a crosslinking agent is used.

Examples of rubber components include vulcanizable or crosslinkable rubbers such as diene rubbers (natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (nitrile rubber), and hydrogenated nitrile rubber. , 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, silicone rubber, Examples thereof include urethane rubber and fluorine rubber.

Examples of the polyurethane resin composition include a cured product of a urethane prepolymer and a curing agent (two-component curable polyurethane).

Among these, an unvulcanized rubber layer is formed with a rubber composition containing sulfur or an organic peroxide (especially an organic peroxide vulcanized rubber composition), and the unvulcanized rubber layer is vulcanized or crosslinked. In particular, in the case of using an olefin resin as a resin component, in addition to excellent adhesiveness, it does not contain harmful halogen, has ozone resistance, heat resistance, cold resistance, and is economical. From the viewpoint, an ethylene-α-olefin elastomer (ethylene-α-olefin rubber) is preferable.

The rubber composition usually contains a vulcanizing agent or a crosslinking agent (particularly an organic peroxide), a vulcanization accelerator, and a co-crosslinking agent (a crosslinking aid or a co-vulcanizing agent). The ratio of the vulcanizing agent or the crosslinking agent is, for example, about 1 to 10 parts by mass (particularly 2 to 5 parts by mass) in terms of solid content with respect to 100 parts by mass of the rubber component. The ratio of the vulcanization accelerator is, for example, about 0.5 to 15 parts by mass (particularly 2 to 5 parts by mass) with respect to 100 parts by mass of the rubber component in terms of solid content. The ratio of the crosslinking aid is, for example, about 0.01 to 10 parts by mass (particularly 0.1 to 5 parts by mass) with respect to 100 parts by mass of the rubber in terms of solid content.

The rubber composition may contain short fibers. As the short fiber, a fiber similar to the fiber exemplified for the heat-resistant fiber can be used. These short fibers can be used alone or in combination of two or more. Among these fibers, cellulose fibers such as cotton and rayon, polyester fibers (PET fibers, etc.), polyamide fibers (aliphatic polyamide fibers such as polyamide 6, aramid fibers, etc.) are widely used.

The average fiber length of the short fibers may be, for example, about 1 to 20 mm, preferably 2 to 15 mm, and more preferably about 3 to 10 mm. The average fiber diameter of the short fibers is, for example, about 5 to 50 μm, preferably 7 to 40 μm, and more preferably about 10 to 30 μm. The proportion of the short fibers is, for example, about 1 to 50 parts by mass (particularly 10 to 35 parts by mass) with respect to 100 parts by mass of the rubber component.

If necessary, the rubber composition may contain conventional additives such as vulcanization aids, vulcanization accelerators, vulcanization retarders, enhancers, fillers, metal oxides, softeners, processing agents or processing aids. An agent, an antioxidant, a colorant, a tackifier, a plasticizer, a coupling agent, a stabilizer, a lubricant, a flame retardant, an antistatic agent, and the like may be included.

The average thickness of the compressed rubber layer can be appropriately selected according to the type of belt, but in the case of a V-ribbed belt, it is, for example, about 2 to 25 mm, preferably about 2.2 to 16 mm, and more preferably about 2.5 to 12 mm.

(Core)
As a fiber which comprises a core wire, the fiber similar to the fiber illustrated by the said heat resistant fiber can be illustrated, for example. Among these, from the viewpoint of high modulus, synthetic fibers such as polyester fibers and aramid fibers, inorganic fibers such as glass fibers and carbon fibers, etc. are widely used, and polyester fibers and aramid fibers are particularly preferable from the viewpoint that the belt slip rate can be reduced. preferable. The polyester fiber may be a multifilament yarn. The fineness of the core wire composed of the multifilament yarn may be, for example, about 2000 to 10000 denier (particularly 4000 to 8000 denier). The core wire may be subjected to a conventional adhesion treatment, for example, an adhesion treatment with a resorcin-formalin-latex liquid (RFL liquid), in order to improve adhesion with the rubber component.

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 arranged in parallel at a predetermined pitch in parallel with the longitudinal direction of the belt.

(Adhesive layer)
For the adhesive layer, the same rubber composition as that exemplified for the compressed rubber layer can be used. In the rubber composition of the adhesive layer, as the rubber component, the same type or type of rubber as the rubber component of the rubber composition of the compressed rubber layer is often used. Further, the ratio of additives such as a vulcanizing agent or a crosslinking agent, a co-crosslinking agent or a crosslinking aid, and a vulcanization accelerator can be selected from the same range as that of the rubber composition of the compressed rubber layer. The rubber composition of the adhesive layer may further contain an adhesion improver (resorcin-formaldehyde cocondensate, amino resin, etc.).

The thickness of the adhesive layer can be appropriately selected according to the type of belt, but in the case of a V-ribbed belt, for example, 0.4 to 3.0 mm, preferably 0.6 to 2.2 mm, and more preferably 0.8 to 1. It is about 4 mm.

(Stretch layer)
The stretch layer may be formed of the same rubber composition as that exemplified for the compressed rubber layer, or may be formed of a fabric (reinforcing fabric) such as a canvas.

Examples of the reinforcing cloth include cloth materials such as woven cloth, wide-angle canvas, knitted cloth, and non-woven cloth. Of these, preferred are woven fabrics woven in the form of plain weave, twill weave, satin weave, etc., wide-angle canvas or knitted fabric in which the crossing angle between warp and weft is about 90 to 120 °. As the fibers constituting the reinforcing cloth, the same fibers as exemplified for the short fibers can be used. The reinforcing cloth may be treated with the RFL solution (immersion treatment or the like) and then friction or rubbing (coating) with the rubber composition to form a canvas with rubber.

Of these, an extension layer formed of a rubber composition is preferable. In the rubber composition of the stretch layer, as the rubber component, the same system or the same type of rubber as the rubber component of the rubber composition of the compressed rubber layer is often used. The ratio of additives such as a vulcanizing agent or a crosslinking agent, a co-crosslinking agent or a crosslinking aid, and a vulcanization accelerator can also be selected from the same range as that of the rubber composition of the compressed rubber layer.

The rubber composition may further contain short fibers similar to those of the compression rubber layer in order to suppress abnormal noise generated due to adhesion of the back rubber when the back surface is driven. The short fibers may be randomly oriented in the rubber composition. Further, the short fiber may be a short fiber partially bent.

Furthermore, an uneven pattern may be provided on the surface of the stretched layer (the back surface of the belt) in order to suppress abnormal noise during backside driving. Examples of the uneven pattern include a knitted fabric pattern, a woven fabric pattern, a suede woven fabric pattern, and an embossed pattern. Of these patterns, a woven fabric pattern and an embossed pattern are preferable. Furthermore, you may coat | cover at least one part of the back surface of an extending | stretching layer with the said fiber resin mixed layer.

The thickness of the stretched layer can be appropriately selected depending on the type of belt, but in the case of a V-ribbed belt, for example, 0.4 to 2 mm, preferably 0.5 to 1.5 mm, more preferably about 0.7 to 1.2 mm. It is.

[Method of manufacturing friction transmission belt]
The friction transmission belt of the present invention comprises a cylindrical drum, a sheet for forming a stretch layer (stretch layer sheet), a core wire, and an unvulcanized rubber sheet (compressed rubber layer) for forming a compressed rubber layer. Sheet) and a fiber resin mixed layer and a sheet-like structure for forming the fiber layer (fiber resin mixed layer and fiber layer structure) are sequentially wound to obtain a laminated sheet, and obtained It is manufactured through a vulcanization molding process in which the laminated sheet is pressed against a mold and the unvulcanized rubber sheet is vulcanized.

Specifically, in the winding process, first, an unvulcanized stretch layer sheet is wound around an inner mold having a flexible jacket mounted on the outer peripheral surface, and a core wire is spun into a spiral shape, and further unvulcanized. The compressed rubber layer sheet, the fiber resin mixed layer, and the fiber layer sheet-like raw material are sequentially wound to produce a molded body.

In this step, the fiber resin mixed layer and the fiber layer structure are formed as separate sheet-like structures (for example, resin components for forming the fiber resin mixed layer and the fiber layer, respectively). It may be a combination of a non-woven fabric in which a fibrous resin component and heat-resistant fibers are mixed, and a non-woven fabric made of hydrophilic heat-resistant fibers. A plurality of sheet-like structures including the sheet-like structure for forming the film is preferable. Combining the sheet-like structure (resin component structure) for forming the resin component with the sheet-like structure (hydrophilic heat-resistant fiber structure) for forming the hydrophilic heat-resistant fiber adds the next step. Since the resin component is melted and impregnated between the hydrophilic heat-resistant fibers by heating and pressurizing in the sulfur molding step, the fiber layer is formed by the non-impregnated portion of the hydrophilic heat-resistant fibers, so that the fibers can be produced by a simple manufacturing method. The layer and the fiber resin mixed layer can be firmly integrated.

The plurality of sheet-like structures include a resin component structure for forming a fiber resin mixed layer and a hydrophilic heat resistant fiber structure for forming a fiber resin mixed layer and a fiber layer. However, it may further include a sheet-like structure (heat-resistant fiber structure) for forming heat-resistant fibers for forming the fiber-resin mixed layer.

The structure of the resin component structure is not limited as long as it can penetrate between the hydrophilic heat-resistant fibers (and between the heat-resistant fibers) to form a fiber resin mixed layer in the vulcanization molding process. For example, a sheet, a film, a woven fabric, a knitted fabric However, a fibrous structure such as a woven fabric, a knitted fabric, or a nonwoven fabric is preferable, and a nonwoven fabric is particularly preferable. A fiber structure such as a non-woven fabric can improve the adhesion to the compressed rubber layer because the fibers are entangled with the hydrophilic heat-resistant fibers (and heat-resistant fibers). In the case of a fiber structure, the average fiber diameter is, for example, about 5 to 50 μm, preferably about 7 to 40 μm, and more preferably about 10 to 35 μm. In the case of short fibers, the average length is, for example, about 1 to 500 mm, preferably about 3 to 300 mm, and more preferably about 5 to 100 mm. The fiber form of the constituent fibers is not particularly limited, and may be any form of monofilament, multifilament, spun yarn (spun yarn), or a combination thereof.

The structure of the hydrophilic heat-resistant fiber structure and the heat-resistant fiber structure may be a woven fabric or a knitted fabric, but is excellent in flexibility and water absorption, and in the fiber resin mixed layer, at the interface with the compressed rubber layer. Nonwoven fabrics are preferred because they can be embedded and firmly integrated with the compressed rubber layer.

The plurality of sheet-like structures may be a combination of a single resin component structure and a single hydrophilic heat-resistant fiber structure, but a combination of a plurality of sheet-like structures, for example, Two resin component structures and two heat-resistant fiber structures (two hydrophilic heat-resistant fiber structures or a total of two hydrophilic heat-resistant fiber structures and heat-resistant fiber structures) It may be a combination. In the combination of a plurality of sheet-like structures, it is advantageous to increase the total thickness of the fiber layer and the resin fiber mixed layer in order to improve the wear resistance and sound generation resistance. Therefore, if the basis weight of each sheet-like structure in the plurality of sheet-like structures is increased, shape defects are likely to occur because the flow of rubber during vulcanization is hindered. On the other hand, when more sheet-like structures are combined, a plurality of sheet-like structures having a relatively small weight per unit area are stacked and wound, so that the rubber during vulcanization flows smoothly or the shape is poor. Generation | occurrence | production can be suppressed and the said total thickness can be enlarged.

As a combination of a plurality of sheet-like structures, a non-woven fabric (1) containing a first thermoplastic resin having a softening point or melting point equal to or lower than the vulcanization temperature, a non-woven fabric (2) containing heat-resistant fibers, and a softening point or melting point Is preferably a combination of a nonwoven fabric (3) containing a second thermoplastic resin having a vulcanization temperature or lower and a nonwoven fabric (4) containing a hydrophilic heat-resistant fiber. In this combination, the nonwoven fabrics (1) and (3) are sheet-like structures for resin components, the nonwoven fabric (2) is a sheet-like structure for heat-resistant fibers, and the nonwoven fabric (4) is a sheet-like structure for hydrophilic heat-resistant fibers. It is a structure. The nonwoven fabrics (1) to (4) are wound around an unvulcanized rubber sheet for forming a compressed rubber layer in this order, and vulcanized in the subsequent vulcanization molding step, whereby the nonwoven fabric (2) The resin component of the melted nonwoven fabric (1) and (3) is impregnated in the entire region and a part of the nonwoven fabric (4) to form a resin fiber mixed layer, and the unimpregnated region of the nonwoven fabric (4) A fiber layer is formed. The first thermoplastic resin and the second thermoplastic resin may be the same or different.

The non-woven fabrics (1) to (4) may be wound with independent non-woven fabrics. However, the non-woven fabric (1) and the non-woven fabric (2) are laminated in advance and then laminated in advance. It is preferable to wind a laminated body of the nonwoven fabric (3) and the nonwoven fabric (4) integrated together. By using a laminated body laminated in advance, in the winding process, it is not necessary to separately wind the nonwoven fabric for forming the resin component and the nonwoven fabric for forming the heat-resistant fiber, and only one winding is required. In addition to being excellent in workability and productivity, it is also possible to suppress the influence on the interface (such as generation of gaps) due to separate winding, and to improve the uniformity of the fiber-resin mixed layer, so the sound resistance and wear resistance of the belt Can also be improved. In addition, the ratio of the nonwoven fabric for forming the resin component and the nonwoven fabric for forming the heat-resistant fiber is a method of changing at least one thickness (for example, a method of increasing the number of windings, a method of combining nonwoven fabrics having different thicknesses, etc.) Can be adjusted easily.

In the present invention, the resin component structure is disposed on the compressed rubber layer side, and the heat-resistant fiber structure or the hydrophilic heat-resistant fiber structure is disposed on the pulley side, thereby softening or melting the resin during vulcanization. Can be reliably coated on the surface of the compressed rubber layer. Furthermore, by arranging the structure for hydrophilic heat-resistant fibers on the outermost surface on the pulley side, a fiber layer that can reliably reflect the characteristics of hydrophilic heat-resistant fibers (for example, water absorption and wear resistance) on the friction transmission surface is formed. it can. Moreover, it can prevent that most heat resistant fibers are embed | buried under the interface inside a compression rubber layer by setting it as such a laminated form. That is, the resin component serves as a barrier that controls the degree of penetration (embedding depth) of the heat-resistant fibers into the vicinity of the interface inside the compressed rubber layer.

Furthermore, among the above combinations, a combination in which the heat resistant fiber of the nonwoven fabric (2) is also a hydrophilic heat resistant fiber is preferable from the viewpoint of improving the sound resistance when wet, and the softening point or the thermoplasticity having a melting point equal to or lower than the vulcanization temperature. A combination of laminated nonwoven fabrics of a first nonwoven fabric containing a resin and a second nonwoven fabric containing hydrophilic heat-resistant fibers (that is, a combination of the same laminated nonwoven fabrics) is particularly preferable. When the same laminated nonwoven fabric is used, the laminated nonwoven fabric having a two-layer structure is wound around the unvulcanized rubber sheet for forming the compressed rubber layer with the first nonwoven fabric inside (compressed rubber layer side). Thus, a laminate having a four-layer structure such as the nonwoven fabrics (1) to (4) can be easily produced.

For producing a fiber layer and a fiber resin mixed layer by using a laminated nonwoven fabric of a first nonwoven fabric containing a thermoplastic resin having a softening point or a melting point equal to or lower than a vulcanization temperature and a second nonwoven fabric containing a hydrophilic heat-resistant fiber A schematic diagram is shown in FIG. On the unvulcanized rubber sheet for forming the compressed rubber layer, a first nonwoven fabric containing a thermoplastic resin having a softening point or a melting point equal to or lower than the vulcanization temperature, and a second nonwoven fabric containing a hydrophilic heat-resistant fiber When the laminated nonwoven fabric is wound twice with the first nonwoven fabric inside (compressed rubber layer side), the first nonwoven fabric and the second nonwoven fabric are alternately laminated on the unvulcanized rubber sheet. . As a result, before vulcanization, as shown in FIG. 2A, the first nonwoven fabric 11a, the second nonwoven fabric 12a, and the first nonwoven fabric sheet 13 are sequentially formed on the unvulcanized rubber sheet 13 from the inside. A laminate having a four-layer structure including the nonwoven fabric 11b and the second nonwoven fabric 12b is formed. When this laminate is vulcanized, as shown in FIG. 2 (b), the first

nonwoven fabrics

11a and 11b are melted and impregnated into the second

nonwoven fabrics

12a and 12b by heating and pressurizing during vulcanization. Then, the fiber-resin mixed layer 14 made of hydrophilic heat-resistant fibers and resin components is formed on the compressed rubber layer 16. Specifically, the second nonwoven fabric 12a is impregnated with the resin component from both layers of the first

nonwoven fabric

11a and 11b, and the second nonwoven fabric 12b is impregnated with the resin component only from the first nonwoven fabric 11b. Therefore, the entire region of the second nonwoven fabric 12a and a partial region (lower region) of the second nonwoven fabric 12b are combined to form the fiber resin mixed layer 14, and the resin component of the second nonwoven fabric 12b is A part of the region that is not impregnated (upper region) forms a fiber layer 15 made of only hydrophilic heat-resistant fibers that do not contain a resin component.

The basis weight of the fiber resin mixed layer and the fiber layer structure (particularly, the laminated nonwoven fabric of the first nonwoven fabric and the second nonwoven fabric) is, for example, 30 to 180 g / m ² , preferably 50 to 150 g / m ² , More preferably, it is about 80 to 120 g / m ² (particularly 90 to 110 g / m ² ). If the weight per unit area is too small, the rubber penetrates to the belt surface and the friction coefficient DRY / WET difference increases, resulting in a decrease in sound resistance, or wear of the surface layer due to running, resulting in a decrease in sound resistance. There is a fear. On the other hand, if the basis weight is too large, the flow of rubber during vulcanization may be hindered, resulting in a shape defect. In addition, the ratio of the fabric weight of each sheet-like structure is adjusted according to the mass ratio of the above-mentioned resin component and fiber component.

In the vulcanization molding process, it is only necessary to vulcanize and mold at least the unvulcanized rubber sheet of the compressed rubber layer by pressing the wound laminated sheet against the mold. For example, in a V-ribbed belt, a plurality of rib molds are provided on the inner peripheral surface. An inner mold in which a molded body is wound around an engraved outer mold is installed concentrically. At this time, a predetermined gap is provided between the inner peripheral surface of the outer mold and the outer peripheral surface of the molded body. Thereafter, the flexible jacket is expanded (for example, about 1 to 6%) toward the inner peripheral surface (rib type) of the outer mold to form a molded body (for example, a fiber resin mixed layer, a fiber layer, and a compressed rubber layer not yet added). (Sulfur rubber sheet) is pressed into the rib mold and vulcanized. Finally, after removing 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 in a V-ribbed belt.

In the present invention, in the vulcanization molding step, it is preferable to perform vulcanization after preheating at a temperature lower than the vulcanization temperature. That is, as a vulcanization pattern after expanding the flexible jacket, a predetermined time (for example, 60 to 120 ° C., preferably 65 to 110 ° C., more preferably about 70 to 100 ° C.) at a low temperature is used. The first step (preheating treatment) for maintaining 2 to 20 minutes, preferably about 3 to 15 minutes), and then raising the temperature to the vulcanization temperature (for example, 150 to 200 ° C., preferably about 160 to 180 ° C.) In this state, it is preferable to constitute a second step for maintaining a predetermined time (for example, 10 to 40 minutes, preferably 15 to 30 minutes). Here, the temperature range of 60 to 120 ° C. was set as a low temperature by reducing (or reducing) the fluidity of the unvulcanized rubber sheet and the resin component structure forming the compressed rubber layer (particularly the surface layer). This is because most of the heat-resistant fibers are prevented from being taken in the vicinity of the interface inside the compressed rubber layer.

Thus, by providing the two temperature steps of the first step (low temperature) and the second step (high temperature), the rib surface is covered with the fiber layer and the fiber resin mixed layer, and the heat resistant fiber contained in the fiber resin mixed layer Can be embedded in the vicinity of the interface inside the compressed rubber layer.

In addition, the said manufacturing method is an example and is not limited to this manufacturing method, It can change variously according to a material and its characteristic. For example, the vulcanization pattern may include at least a first step and a second step, and another temperature step may be provided between the first step and the second step.

Other than the manufacturing method, the members and their thicknesses may be appropriately combined, and the fluidity of the thermoplastic resin constituting the resin component structure or the rubber composition constituting the unvulcanized rubber sheet of the compressed rubber layer Low materials may be used.

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, measurement methods or evaluation methods for each physical property, and raw materials used in the examples are shown below.

[Beding depth]
A V-ribbed belt is cut in a direction parallel to the belt width direction, and this cut surface (particularly, the rib side) is magnified using a scanning electron microscope (“JSM5900LV” manufactured by JEOL Ltd.) (magnification is 50 ×). Then, the embedding depth of the heat resistant fiber embedded in the vicinity of the interface with the fiber resin mixed layer inside the compressed rubber layer was measured as follows.

1) Since the rib side surface is substantially straight, a straight line A is drawn along the boundary between the fiber resin mixed layer and the surface layer of the compression layer (heat-resistant fiber buried layer).

2) A perpendicular line B is drawn toward the straight line A from any five points (boundary between the heat-resistant fiber buried layer and the inner layer not buried) between the rib groove side, the rib tip side, and the perpendicular line B. Find the length of.

3) The lengths of the five perpendicular lines B obtained in 2) are averaged to obtain the embedment depth of the heat-resistant fiber.

[Coefficient of friction]
The friction coefficient measurement test was performed using a drive pulley (Dr.) having a diameter of 121.6 mm, an idler pulley (IDL.1) having a diameter of 76.2 mm, an idler pulley having a diameter of 61.0 mm (IDL.2), and an idler having a diameter of 76.2 mm. The test was performed using a testing machine having a layout shown in FIG. 3 in which a pulley (IDL.3), an idler pulley (IDL.4) having a diameter of 77.0 mm, and a driven pulley (Dn.) Having a diameter of 121.6 mm were sequentially arranged. Then, a V-ribbed belt is hung on each pulley of the test machine, and during normal driving (DRY), the rotational speed of the driving pulley is 400 rpm and the belt winding angle around the driven pulley is 20 ° under room temperature conditions (25 ° C.). When a belt is run with a constant load (180 N / 6 Rib) applied, the torque of the driven pulley is increased from 0 to a maximum of 20 Nm, and the belt sliding speed with respect to the driven pulley reaches the maximum (100% slip). From the torque value of the driven pulley, the friction coefficient μ was obtained using the following equation.

Μ = ln (T1 / T2) / α

Here, T1 is the tension on the tension side, T2 is the tension on the loose side, and α is the belt winding angle around the driven pulley, which can be obtained by the following equations, respectively.

T1 = T2 + Dn. Torque (kgf · m) / (121.6 / 2000)
T2 = 180 (N / 6 Rib)
α = π / 9 (rad) (where rad means radians).

During water injection (WET), as shown in the layout of FIG. 4, the rotational speed of the drive pulley is 800 rpm, the belt winding angle around the driven pulley is 45 ° (α = π / 4), and 1 near the inlet of the driven pulley. Except for continuing to pour 300 ml of water per minute, it was the same as in normal running, and the friction coefficient μ was similarly determined using the above equation.

[Sounding limit angle]
The misalignment sound generation evaluation test (sound generation limit angle) consists of a 90 mm diameter drive pulley (Dr.), a 70 mm diameter idler pulley (IDL.1), a 120 mm diameter misalignment pulley (W / P), and a 80 mm diameter tension pulley. (Ten.), An idler pulley (IDL.2) having a diameter of 70 mm, and an idler pulley (IDL.3) having a diameter of 80 mm are arranged in this order, and the tester shown in FIG. And the misalignment pulley axial separation (span length) was set to 135 mm, and all the pulleys were adjusted to be positioned on the same plane (misalignment angle 0 °). Then, a V-ribbed belt is hung on each pulley of the testing machine, and tension is applied so that the rotational speed of the driving pulley is 1000 rpm and the belt tension is 300 N / 6 Rib under room temperature conditions. When 5 cc of water is periodically poured into the friction transmission surface of the ribbed belt (at intervals of about 30 seconds) and the belt is driven by misalignment (the misalignment pulley is shifted to the front side of each pulley) The angle (pronunciation limit angle) when the vicinity of the inlet of the alignment pulley occurs was obtained. In addition, the sounding limit angle was obtained in the same way during normal driving (same layout and driving conditions as during water injection except that water is not injected). The larger the numerical value of the sounding limit angle, the better the sounding resistance, and the sounding resistance was judged to be good when the sounding limit angle during flooding and normal running was 2.0 ° or more.

[Abrasion rate]
The wear test is shown in FIG. 6 in which a driving pulley (Dr.) with a diameter of 120 mm, an idler pulley (IDL.) With a diameter of 85 mm, a driven pulley (Dn.) With a diameter of 120 mm, and a tension pulley (Ten.) With a diameter of 60 mm are arranged in this order. The test was performed using a testing machine showing the layout. A V-ribbed belt is hung on each pulley of the testing machine, the rotational speed of the drive pulley is 4900 rpm, the belt winding angle around the idler pulley and the tension pulley is 90 °, the driven pulley load is 10.4 kW, and a constant load (91 kg) / 6 Rib) and the belt was run at an ambient temperature of 120 ° C. for 24 hours. The wear rate was determined by dividing the amount of wear (= belt mass before running−belt mass after running) by the belt mass before running. The lower the value of the wear rate, the better the wear resistance. If this value was 1.4% or less, it was judged that the wear resistance was good.

[Evaluation of abnormal noise when wet with actual vehicle]
The test vehicle was a commercial vehicle equipped with a 4-cylinder engine with a displacement of 1.5 liters, and the engine oil temperature before the start of measurement was 40 ° C. or lower. First, the V-ribbed belt is attached to the engine with a predetermined tension, and then 2 cc of water is injected onto the friction transmission surface of the V-ribbed belt. Finally, the engine is started five times, and the following evaluation points are evaluated. The lowest evaluation score was taken as the evaluation score for the belt.

(Evaluation points)
5 ... No sound, permissible 4 ... Slight sound, permissible (no audible noise on the side of the vehicle when the hood is closed)
3 ... Small pronunciation, acceptable (no abnormal noise in the driver's seat even when the window is open)
2 ... Unacceptable during sound generation (noise is heard in the driver's seat with the window open)
1 ... Large pronunciation, unacceptable (noisy).

[Durability test]
In the durability running test, a driving pulley (Dr.) having a diameter of 120 mm, an idler pulley (IDL.) Having a diameter of 70 mm, a driven pulley (Dn.) Having a diameter of 120 mm, and a tension pulley (Ten.) Having a diameter of 61 mm are sequentially arranged. The test was performed using a testing machine showing the layout. A V-ribbed belt is hung on each pulley of the testing machine, the rotational speed of the drive pulley is 4900 rpm, the belt winding angle around the idler pulley is 120 °, the belt winding angle around the tension pulley is 90 °, and the driven pulley load Was 11.4 kW, a constant load (890 N / 6 Rib) was applied, and the belt was run at an ambient temperature of 120 ° C. for 150 hours. With respect to the V-ribbed belt after running, the friction coefficient and the sound generation limit angle were measured, and an abnormal noise evaluation was performed when the actual vehicle was wet.

[Remaining surface layer after running for 150 hours]
The belt was cut in a direction parallel to the belt width direction before and after the 150-hour durability running test, and this cut surface was observed with an SEM. The thickness of the surface layer before running (fiber resin mixed layer + hydrophilic heat-resistant fiber layer) and the thickness of the surface layer after running were measured and calculated as the thickness of the surface layer after running / the thickness of the surface layer before running. .

[Resin components used in comparative examples]
Table 1 shows thermoplastic resins that are disposed on the compressed rubber layer side and serve as the resin component of the fiber resin mixed layer in the comparative example.

Thermoplastic resin A (“Multitron” manufactured by Tamapoly Co., Ltd.) is in the form of a film made of polyethylene (melting point: 130 ° C.), has a thickness of 0.04 mm, and a basis weight of 38 g / m ² .

The thermoplastic resin B1 (“Stratec” manufactured by Idemitsu Unitech Co., Ltd.) is in the form of a nonwoven fabric composed of long fibers made of polyethylene (melting point: 125 ° C.), and has a thickness of 0.20 mm and a basis weight of 30 g / m ² .

Thermoplastic resin B2 (“Stratec” manufactured by Idemitsu Unitech Co., Ltd.) is a nonwoven fabric made of long fibers of polyethylene (melting point 125 ° C.), and 4% by mass of a nonionic surfactant is kneaded into the fibers. The thickness is 0.20 mm, and the basis weight is 30 g / m ² .

Thermoplastic resin C (“Spunbond nonwoven fabric” manufactured by Shinwa Co., Ltd.) is a nonwoven fabric composed of a composite long fiber having a core of polypropylene (melting point 170 ° C.) and a sheath of polyethylene (melting point 125 ° C.), and has a thickness of 0.00. The weight is 20 mm and the basis weight is 30 g / m ² .

[Nonwoven fabric used in Examples and Comparative Examples]
The nonwoven fabrics used in the examples and comparative examples are shown in Table 2. Nonwoven fabrics E to J are nonwoven fabrics arranged on the pulley side with respect to the resin component in the comparative example. Nonwoven fabrics K and L are nonwoven fabrics used in the examples, and nonwoven fabric M is a nonwoven fabric used in the comparative examples.

Details of each nonwoven fabric are as follows, and the characteristics of each nonwoven fabric are summarized in Table 2.

Non-woven fabric E: “Cot Ace” manufactured by Unitika Ltd., cotton non-woven fabric, thickness 0.15 mm, fiber length 5-50 mm, basis weight 30 g / m ²
Non-woven fabric F: “Cot Ace” manufactured by Unitika Co., Ltd., cotton non-woven fabric, thickness 0.23 mm, fiber length 5-50 mm, basis weight 45 g / m ²
Non-woven fabric G: “Clavion” manufactured by Ohmi Kenshi Co., Ltd., rayon non-woven fabric, thickness 0.20 mm, fiber length 5-50 mm, basis weight 40 g / m ²
Non-woven fabric H: “Clavion” manufactured by Omikenshi Co., Ltd., a non-woven fabric in which rayon short fibers having a fiber length of about 50 mm and polyethylene terephthalate (PET) long fibers are mixed randomly, rayon short fibers / PET long fibers = 70/30 (mass ratio) ), Thickness 0.21 mm, basis weight 40 g / m ²
Non-woven fabric I: “Clavion” manufactured by Ohmi Kenshi Co., Ltd., a non-woven fabric in which rayon staple fibers having a fiber length of about 50 mm, PET filament fibers, and polyethylene (PE) filaments having a melting point of 125 ° C. are randomly blended, rayon staple fibers / PET filaments / PE long fiber = 70/15/15 (mass ratio), thickness 0.21 mm, basis weight 40 g / m ²
Nonwoven fabric J: “Stramity” manufactured by Idemitsu Unitech Co., Ltd., laminate of non-woven paper (thickness 0.25 mm) of pulp having a fiber length of 2 to 7 mm and nonwoven fabric of PE long fibers (melting point 125 ° C., thickness 0.10 mm) Body, basis weight 30g / m ²
Non-woven fabric K: “Noast Strong” manufactured by Ozu Sangyo Co., Ltd., laminate of non-woven paper of 10 mm fiber length and non-woven fabric of polypropylene (PP) long fiber (melting point 170 ° C.), weight per unit area 80 g / m ²
Nonwoven fabric L: “No Strong” manufactured by Ozu Sangyo Co., Ltd., laminate of non-woven paper of pulp having a fiber length of 10 mm (thickness 0.28 mm) and nonwoven fabric of PP long fibers (melting point 170 ° C., thickness 0.10 mm), Weight per unit area 100 g / m ²
Nonwoven fabric M: “Noast Strong” manufactured by Ozu Sangyo Co., Ltd., laminate of non-woven paper (thickness 0.32 mm) of pulp having a fiber length of 10 mm and nonwoven fabric of PP long fibers (melting point 170 ° C., thickness 0.10 mm), Weight per unit area 200 g / m ²
Non-woven fabric N: “Noast Strong” manufactured by Ozu Sangyo Co., Ltd., laminate of non-woven paper of pulp having a fiber length of 10 mm (thickness 0.31 mm) and nonwoven fabric of PP long fibers (melting point 170 ° C., thickness 0.07 mm), Weight per unit area 100 g / m ²
Nonwoven fabric O: “Noast Strong” manufactured by Ozu Sangyo Co., Ltd., laminate of non-woven paper of pulp having a fiber length of 10 mm (thickness 0.20 mm) and nonwoven fabric of PP long fibers (melting point 170 ° C., thickness 0.17 mm), The basis weight is 100 g / m ² .

[Compressed rubber layer, stretch layer, core wire raw material]
EPDM polymer: “IP3640” manufactured by DuPont Dowelasmer Japan Co., Ltd.
Carbon black HAF: “Seast 3” manufactured by Tokai Carbon Co., Ltd.
Anti-aging agent: “Nonflex OD3” manufactured by Seiko Chemical Co., Ltd.
Nylon short fiber: Nylon 66, fiber length about 0.5mm
Organic peroxide: “Parkadox 14RP” manufactured by Kayaku Akzo Corporation
Core wire: A twisted cord obtained by adhering a cord of total denier 6,000, in which 1,000 denier PET fibers are twisted in a 2 × 3 configuration with an upper twist coefficient of 3.0 and a lower twist coefficient of 3.0.

Examples 1-2 and Comparative Examples 1-12
(Formation of compressed rubber layer and stretch layer)
The rubber composition shown in Table 3 was kneaded with a Banbury mixer and rolled with a calender roll to produce rubber sheets for forming a compressed rubber layer or an extended layer with a thickness of 2.5 mm or 0.8 mm, respectively. did.

(Manufacture of belts)
An unvulcanized stretch layer sheet is wound around an inner mold having a flexible jacket on the outer peripheral surface, and a core wire is spirally spun onto this (pitch 1.15 mm, tension 5 kgf). A belt was prepared by sequentially winding a sheet for a compressed rubber layer and a structure for a fiber layer and a fiber resin mixed layer. In Examples 1 to 4, the structure (nonwoven fabric K, L, N, or O) was wound twice, and in the comparative example, the structure was wound only once. Vulcanization is performed by setting the expansion pressure of the flexible jacket to 1.0 MPa, maintaining the temperature at 80 ° C. for 10 minutes (first step), then increasing the temperature to 170 ° C., and maintaining the temperature for 20 minutes (first step). Two steps). After completion of vulcanization, the product was cooled to near room temperature, the inner mold was removed from the outer mold, and the vulcanized belt sleeve was removed from the outer mold.

As the structure for the fiber layer and the fiber resin mixed layer, 16 types of belts shown in Tables 4 and 5 were prepared using the resin components shown in Table 1 and the nonwoven fabric shown in Table 2. In Examples 1 to 4, PP nonwoven fabrics of nonwoven fabrics K, L, N and O shown in Table 2 were placed on the compressed rubber layer side (pulp nonwoven paper was on the pulley side) and wound twice. In Comparative Examples 1 to 7 and 9, the resin component shown in Table 1 was placed on the compressed rubber layer side, the non-woven fabric shown in Table 2 was placed on it (pulley side), and wound once. In Comparative Example 8, the PE nonwoven fabric of the nonwoven fabric J in Table 2 was placed on the compressed rubber layer side (pulp nonwoven paper was on the pulley side) and wound once. In Comparative Examples 10 to 12, the nonwoven fabrics K, L, and M of Table 2 were placed on the compressed rubber layer side (pulp nonwoven paper was on the pulley side) and wound once. The manufactured V-ribbed belt was 6 ribs with a belt length of 1100 mm and a rib shape of K-type.

As a result of comparing the materials of the fiber layer and the fiber resin mixed layer with respect to the obtained V-ribbed belt, the evaluation results of the belts obtained in Examples 1 to 4 and Comparative Examples 1 to 9 are shown in Table 4. Table 5 shows the results of comparing the structures of the fiber layer and the fiber resin mixed layer for the belts obtained in 2-2 and Comparative Examples 10-12.

From the results shown in Table 4, Comparative Examples 1 to 9 are excellent in sound resistance at the time of misalignment by covering the friction transmission surface with a fiber resin mixed layer. It was low. This reason is considered to be due to the relatively large difference in friction coefficient between DRY and WET. In Comparative Examples 1 to 9, it is considered that the difference in friction coefficient between DRY and WET was relatively large because the resin component having low hydrophilicity covered most of the friction transmission surface.

On the other hand, Examples 1 to 4 have a structure in which the friction transmission surface is covered with a hydrophilic heat-resistant fiber layer. With this structure, the hydrophilic heat-resistant fiber layer quickly absorbs water that has entered between the belt and the pulley when exposed to water, and no water film is formed between the belt and the pulley so that there is no difference in the coefficient of friction during DRY and WET. In the actual vehicle wet noise evaluation, high sound resistance of an evaluation score of 5 was shown. Thus, it was confirmed that by providing the fiber layer on the fiber resin mixed layer, there is no difference in the friction coefficient between DRY and WET, and the sound resistance is remarkably increased. The belt obtained in Example 4 had a large resin component and a small amount of heat-resistant fiber, so the friction coefficient at the time of WET was slightly lower than that of Examples 1 to 3, but the noise when the actual vehicle was wet There was no difference in evaluation, and there was no problem in practical use.

As is apparent from the results in Table 5, Comparative Example 12 is an example in which the basis weight of the nonwoven fabric is as large as 200 g / m ² , but the shape was poor because the rubber flow during vulcanization was hindered.

When Examples 1 and 2 and Comparative Examples 10 and 11 were new (before endurance running), the misalignment pronunciation evaluation test did not produce sound until rib misalignment, and the actual vehicle wet noise evaluation showed an evaluation score of 5 and good results. It was. However, the sound resistance after the endurance running test was different between the example and the comparative example.

In Examples 1 and 2, the difference in the friction coefficient between DRY and WET was 0.3 or less even after the durability running test, whereas in Comparative Examples 10 and 11, the difference was considerably large. It was. Further, in the misalignment pronunciation evaluation test, Examples 1 and 2 were at a good level with a pronunciation limit angle of 2 ° or more, whereas in Comparative Examples 10 and 11, the pronunciation limit angle at WET was 1 °. There was a pronounced misalignment that could occur in a real car. In the actual vehicle wet noise evaluation after the endurance running test, Examples 1 and 2 showed an acceptable score of 3 or more, which was a good result, but Comparative Examples 10 and 11 The evaluation points were 1 and 2, which were unacceptable levels.

FIG. 8 shows a scanning electron micrograph of the rib cross section of the V-ribbed belt obtained in Example 2. As is clear from FIG. 8, in the rib cross section of the belt of Example 2, the heat-resistant fiber of the fiber resin mixed layer is embedded inside the vicinity of the surface with the compressed rubber layer, and the fiber resin mixed layer and the fiber are further formed thereon. Layer was formed. On the other hand, in the rib cross section of the V-ribbed belt obtained in Comparative Examples 10 and 11, only the fiber resin mixed layer in which the resin component and the heat resistant fiber were integrated was formed, and the fiber layer was not formed.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2017-054859 filed on March 21, 2017 and Japanese Patent Application No. 2018-041186 filed on March 7, 2018, the contents of which are incorporated herein by reference.

The friction transmission belt of the present invention can be used for various friction transmission belts such as a V-ribbed belt, a low-edge V-belt, and a flat belt, and is particularly useful for a V-ribbed belt and a V-belt used for driving an automobile engine accessory. .

DESCRIPTION OF SYMBOLS 1 ... Core wire 2 ... Compression rubber layer 3 ... Rib part 4 ... Short fiber 5 ... Stretch layer 6 ... Adhesive layer

Claims

A stretch layer that forms the back surface of the belt, a compression rubber layer that is formed on one surface of the stretch layer and that frictionally engages with the pulley, and a longitudinal direction of the belt between the stretch layer and the compression rubber layer A friction transmission belt with a core wire embedded along the
The compressed rubber layer has a surface in contact with the pulley;
At least a part of the surface is covered with a fiber layer via a fiber resin mixed layer,
The fiber resin mixed layer includes a resin component and a heat-resistant fiber having a softening point or a melting point exceeding the vulcanization temperature of the rubber forming the compressed rubber layer,
The said fiber layer is a friction transmission belt containing the hydrophilic heat-resistant fiber which has a softening point or melting | fusing point exceeding the said vulcanization temperature, and does not contain a resin component.
The friction transmission belt according to claim 1, wherein the heat resistant fiber includes a fiber embedded from the fiber resin mixed layer to the compressed rubber layer.
The friction transmission belt according to claim 1 or 2, wherein the resin component is a thermoplastic resin that can be melted or softened at the vulcanization temperature.
The friction transmission belt according to any one of claims 1 to 3, wherein the resin component is a polypropylene resin.
The friction transmission belt according to any one of claims 1 to 4, wherein the hydrophilic heat-resistant fiber is a cellulosic fiber.
The friction transmission belt according to any one of claims 1 to 5, wherein the heat resistant fiber is a cellulosic fiber.
A fiber component (fiber component) that is the sum of the resin component (resin component) contained in the fiber resin mixed layer, the heat resistant fiber contained in the fiber resin mixed layer, and the hydrophilic heat resistant fiber contained in the fiber layer. 7. The friction transmission belt according to any one of claims 1 to 6, wherein a mass ratio with respect to (A) is (resin component) / (fiber component) = 50/50 to 20/80.
The friction transmission belt according to any one of claims 1 to 7, wherein the compressed rubber layer is a V-ribbed belt having a plurality of ribs extending in parallel to each other in the belt longitudinal direction.
To form a sheet for forming the stretched layer, the core wire, an unvulcanized rubber sheet for forming the compressed rubber layer, the fiber resin mixed layer and the fiber layer on a cylindrical drum And a vulcanization molding step of vulcanizing and molding the unvulcanized rubber sheet by pressing the laminated sheet against a mold. A method,
The method for producing a friction transmission belt according to any one of claims 1 to 8, wherein in the vulcanization molding step, the unvulcanized rubber sheet is preheated at a temperature lower than the vulcanization temperature and then vulcanized.
In the winding step, as the sheet-like structure, a non-woven fabric (1) containing a first thermoplastic resin having a softening point or melting point equal to or lower than the vulcanization temperature, a non-woven fabric (2) containing the heat-resistant fiber, and softening The manufacturing method of Claim 9 which winds the nonwoven fabric (3) containing the 2nd thermoplastic resin whose point or melting | fusing point is below the said vulcanization temperature, and the nonwoven fabric (4) containing the said hydrophilic heat-resistant fiber in this order.
In the winding step, a laminated nonwoven fabric of a first nonwoven fabric containing a thermoplastic resin having a softening point or a melting point equal to or lower than the vulcanization temperature and a second nonwoven fabric containing the hydrophilic heat-resistant fibers as the sheet-like structure. The manufacturing method according to claim 9, wherein the first nonwoven fabric is wound inside in a double manner.
The production method according to any one of claims 9 to 11, wherein the basis weight of the sheet-like structure is 50 to 150 g / m 2 .