Transmission belt, method for manufacturing same, and core wire and epoxy treatment agent used for same

Abstract

In this transmission belt (B), a core wire (12) composed of twisted yarn is embedded in a belt body (11). The twisted yarn constituting the core wire (12) is subjected to an epoxy treatment in which the twisted yarn is: immersed in an epoxy treatment agent containing a first epoxy material mainly composed of a first epoxy compound having at least three epoxy groups in the molecule and a second epoxy material mainly composed of a second epoxy compound having at most two epoxy groups in the molecule; withdrawn; and then heated.

Description

Drive belt, method for manufacturing the same, core wire used therefor, and epoxy treatment agent

[0001] The present invention relates to a drive belt, a method for manufacturing the same, a core wire used therefor, and an epoxy treatment agent.

[0002] For the core wire embedded in the belt body of the drive belt, a core wire that has been subjected to a process of being immersed in various treatment agents, pulled up, and then heated for adhesion to the belt body or the like is used. For example, Patent Documents 1 and 2 disclose a core wire for a drive belt in which a filament bundle of carbon fibers is immersed in a treatment agent containing an epoxy resin and a rubber latex, pulled up, heated, and then twisted.

[0003] Japanese Patent Application Laid-Open No. 2005-042229, Japanese Patent Application Laid-Open No. 2003-247127

[0004] The present invention is a drive belt in which a core wire composed of twisted yarn is embedded in a belt body, and the twisted yarn constituting the core wire is immersed in an epoxy treatment agent containing a first epoxy material mainly composed of a first epoxy compound having three or more epoxy groups in the molecule and a second epoxy material mainly composed of a second epoxy compound having two or less epoxy groups in the molecule, pulled up, and then heated.

[0005] The present invention is a method for manufacturing a drive belt in which a core wire composed of twisted yarn is embedded in a belt body, and includes a step of immersing the twisted yarn constituting the core wire in an epoxy treatment agent containing a first epoxy material mainly composed of a first epoxy compound having three or more epoxy groups in the molecule and a second epoxy material mainly composed of a second epoxy compound having two or less epoxy groups in the molecule, pulling up, and then heating.

[0006] The present invention is a core wire composed of twisted yarn embedded in a belt body of a drive belt, and the twisted yarn constituting the core wire is immersed in an epoxy treatment agent containing a first epoxy material mainly composed of a first epoxy compound having three or more epoxy groups in the molecule and a second epoxy material mainly composed of a second epoxy compound having two or less epoxy groups in the molecule, pulled up, and then heated.

[0007] The present invention relates to an epoxy treatment agent used for treating the twisted yarn that constitutes the core wire embedded in the belt body of a power transmission belt, and comprises a first epoxy material mainly composed of a first epoxy compound having three or more epoxy groups in its molecule, and a second epoxy material mainly composed of a second epoxy compound having two or fewer epoxy groups in its molecule.

[0008] This is a perspective view of one piece of a toothed belt according to the embodiment. This is a front view taken along arrow X in Figure 1A. This is an IC-IC cross-sectional view (of two teeth) in Figure 1B. This is a cross-sectional view of a part of the belt forming die. This is the first explanatory diagram of the method for manufacturing a toothed belt according to the embodiment. This is the second explanatory diagram of the method for manufacturing a toothed belt according to the embodiment. This is the third explanatory diagram of the method for manufacturing a toothed belt according to the embodiment.

[0009] The embodiments will be described in detail below.

[0010] Figures 1A to 1C show a toothed belt B according to an embodiment. This toothed belt B is an endless interlocking power transmission belt used, for example, in automobiles and general industrial machinery.

[0011] The toothed belt B according to this embodiment has a plurality of teeth 10A. The plurality of teeth 10A are arranged at a predetermined pitch P in the direction of the length of the belt and are formed to protrude toward the inner circumference of the belt. In addition, the space between a pair of adjacent teeth 10A is formed by a tooth root 10B.

[0012] The teeth 10A are so-called round teeth with a semicircular cross-sectional shape, but they may also be of other shapes, such as trapezoidal teeth with a trapezoidal cross-sectional shape. The teeth 10A may be composed of protrusions formed to extend in the belt width direction, or they may be so-called serrated teeth composed of protrusions formed to extend in a direction inclined with respect to the belt width direction.

[0013] The belt length (circumference along the belt pitch line L) of the toothed belt B according to this embodiment is, for example, 225 mm or more and 6000 mm or less. The belt width is, for example, 10 mm or more and 120 mm or less. The maximum belt thickness is, for example, 2 mm or more and 9.5 mm or less.

[0014] The pitch P of the teeth 10A is, for example, 3 mm to 14 mm. The height of the teeth 10A is, for example, 1 mm to 6.5 mm. This height of the teeth 10A is defined by the distance from the tooth root 10B to the tip of the teeth 10A. The width of the teeth 10A is, for example, 1.5 mm to 9.5 mm. This width of the teeth 10A is defined by the distance between the ends of a pair of adjacent tooth roots 10B that sandwich the teeth 10A in the belt length direction.

[0015] The toothed belt B according to this embodiment comprises a belt body 11, a core wire 12, and a reinforcing fabric 13.

[0016] The belt body 11 has a flat rubber band portion 111 and a plurality of toothed body portions 112. The plurality of toothed body portions 112 are integrally provided on the inner circumferential surface of the flat rubber band portion 111 at regular intervals. The belt body 11 is formed from a rubber composition in which an uncrosslinked rubber composition, which contains various rubber compounding agents including a crosslinking agent, is heated and pressurized so that the rubber components are crosslinked by the crosslinking agent.

[0017] Examples of rubber components in the rubber composition forming the belt body 11 include hydrogenated nitrile rubber (H-NBR), chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), and ethylene-α-olefin elastomer (ethylene propylene dienterpolymer (EPDM), etc.). Examples of crosslinking agents include organic peroxides and sulfur. Examples of rubber compounding agents other than crosslinking agents include vulcanization accelerators, antioxidants, reinforcing agents, plasticizers, and co-crosslinking agents.

[0018] The core wire 12 is embedded in the inner circumference portion of the flat rubber band 111 of the belt body 11. The core wire 12 is arranged to form a spiral with a pitch in the belt width direction.

[0019] The core wire 12 is composed of twisted yarn made of carbon fiber, glass fiber, aramid fiber, metal fiber, polyester fiber, nylon fiber, etc. Preferably, the core wire 12 is provided with S-twisted yarn and Z-twisted yarn forming a double helix, but it may also be provided with only a single S-twisted yarn or a Z-twisted yarn.

[0020] The twisted yarn constituting the core wire 12 has a fineness of, for example, 2500 dtex or more and 10000 dtex or less. In the case of carbon fiber, the number of filaments is, for example, 6000 (6K) or more and 48000 (48K) or less.

[0021] The twisted threads constituting the core wire 12 are subjected to epoxy treatment by being immersed in an epoxy treatment agent containing a first epoxy material mainly composed of a first epoxy compound having three or more epoxy groups in its molecule, and a second epoxy material mainly composed of a second epoxy compound having two or fewer epoxy groups in its molecule, then pulled out and heated.

[0022] According to the toothed belt B of this embodiment, the twisted yarn constituting the core wire 12 is subjected to epoxy treatment by being immersed in an epoxy treatment agent containing a first epoxy material mainly composed of a first epoxy compound having three or more epoxy groups in its molecule, and a second epoxy material mainly composed of a second epoxy compound having two or fewer epoxy groups in its molecule, then pulled out and heated. This treatment allows for high filament convergence of the core wire 12. This is thought to be because the epoxy treatment agent contains both the first and second epoxy materials, allowing the epoxy treatment agent to penetrate even into the extremely narrow gaps inside the twisted yarn, and forming a three-dimensional cross-linked structure with epoxy resin. As a result, the generation of fuzz on the cut surfaces of the core wire 12 exposed on both sides of the belt can be suppressed.

[0023] Here, the epoxy treatment agent is preferably an aqueous treatment agent from the viewpoint of ease of handling. The aqueous epoxy treatment agent may be an aqueous solution obtained by dissolving the first and second epoxy materials in water, a dispersion obtained by dispersing the first and second epoxy materials in water, or a dispersion obtained by dissolving one of the first and second epoxy materials in water and dispersing the other. The epoxy treatment agent may also be a solvent-based treatment agent obtained by dissolving the first and second epoxy materials in a solvent such as toluene.

[0024] Since the first epoxy compound is the main component of the first epoxy material, the content of the first epoxy compound in the first epoxy material is more than 50% by mass, preferably 90% by mass or more, more preferably 95% by mass or more, and most preferably 100% by mass, from the viewpoint of obtaining high filament focusing properties of the core wire 12.

[0025] From the viewpoint of obtaining high filament focusing properties of the core wire 12, the first epoxy compound preferably has 3 to 5 epoxy groups in its molecule, and more preferably has 4 epoxy groups in its molecule. Examples of hydrophilic first epoxy compounds include sorbitol polyglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, and polyglycerol polyglycidyl ether. Examples of hydrophobic first epoxy compounds include trimethylolpropane polyglycidyl ether. The first epoxy compound preferably contains one or more of these, and from the same viewpoint as above, it is more preferable to contain a hydrophilic first epoxy compound, and even more preferable to contain sorbitol polyglycidyl ether.

[0026] The epoxy equivalent of the first epoxy material is preferably 160 g to 180 g, more preferably 171 g to 175 g, from the viewpoint of obtaining high filament bundling of the core wire 12. In this application, "epoxy equivalent of epoxy material" is the number of grams of epoxy material containing 1 mole of epoxy groups. Furthermore, this epoxy equivalent is measured in accordance with JIS K7236:2009.

[0027] The viscosity of the first epoxy material is preferably 1,000 mPa·s to 10,000 mPa·s, and more preferably 4,000 mPa·s to 6,000 mPa·s, from the viewpoint of obtaining high filament focusing of the core wire 12. In this application, the viscosity of the epoxy material is measured at a sample temperature of 25°C in accordance with JIS K7233:1986.

[0028] Since the second epoxy compound is the main component of the second epoxy material, the content of the second epoxy compound in the second epoxy material is more than 50% by mass, preferably 90% by mass or more, more preferably 95% by mass or more, and most preferably 100% by mass, from the viewpoint of obtaining high filament focusing properties of the core wire 12.

[0029] From the viewpoint of obtaining high filament focusing properties of the core wire 12, the second epoxy compound preferably has two epoxy groups in its molecule. Examples of hydrophilic second epoxy compounds include polyethylene glycol diglycidyl ether and ethylene glycol diglycidyl ether. Examples of hydrophobic second epoxy compounds include resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, phthalate diglycidyl ester, and polypropylene glycol diglycidyl ether. The second epoxy compound preferably contains one or more of these, and from the same viewpoint as above, it is more preferable to contain a hydrophilic second epoxy compound, even more preferable to contain polyethylene glycol diglycidyl ether, and even more preferable to contain polyethylene glycol diglycidyl ether with 2 ethylene glycol units.

[0030] The epoxy equivalent of the second epoxy material is preferably 120 g to 170 g, more preferably 140 g to 160 g, from the viewpoint of obtaining high filament bundling of the core wire 12. The viscosity of the second epoxy material is preferably 10 mPa·s to 100 mPa·s, more preferably 25 mPa·s to 35 mPa·s, from the same viewpoint.

[0031] From the viewpoint of obtaining high filament bundling properties of the core wire 12, the epoxy equivalent of the first epoxy material is preferably higher than that of the second epoxy material. From the same viewpoint, the ratio of the epoxy equivalent of the first epoxy material to the epoxy equivalent of the second epoxy material (epoxy equivalent of the first epoxy material / epoxy equivalent of the second epoxy material) is preferably 1.05 or more and 1.5 or less, more preferably 1.1 or more and 1.2 or less. From the same viewpoint, the viscosity of the first epoxy material is preferably higher than that of the second epoxy material. From the same viewpoint, the ratio of the viscosity of the first epoxy material to the viscosity of the second epoxy material (viscosity of the first epoxy material / viscosity of the second epoxy material) is preferably 100 or more and 250 or less, more preferably 150 or more and 200 or less.

[0032] From the viewpoint of obtaining high filament focusing properties of the core wire 12, the epoxy treatment agent preferably contains, in addition to the first and second epoxy materials, an epoxy resin curing agent for curing them. From the same viewpoint, the epoxy resin curing agent is preferably an imidazole-based epoxy resin curing agent, and more preferably an imidazole-based epoxy resin curing agent containing a CN group.

[0033] From the viewpoint of obtaining high filament convergence of the core wire 12, the solid content concentration of the epoxy treatment agent is preferably 40% by mass or more and 80% by mass or less, more preferably 50% by mass or more and 70% by mass or less. From the same viewpoint, the mass ratio of the content of the first epoxy material in the epoxy treatment agent to the content of the second epoxy material is preferably 20 / 80 or more and 95 / 5 or less, more preferably 40 / 60 or more and 90 / 10 or less, and even more preferably 50 / 50 or more and 80 / 20 or less.

[0034] The molar content X of the first epoxy group, obtained by dividing the content of the first epoxy material per 100 g of epoxy treatment agent by the epoxy equivalent of the first epoxy material, is preferably 0.05 mol / 100 g or more and 0.3 mol / 100 g or less, and more preferably 0.15 mol / 100 g or more and 0.25 mol / 100 g or less, from the viewpoint of obtaining high filament bundling properties of the core wire 12. The molar content Y of the second epoxy group, obtained by dividing the content of the second epoxy material per 100 g of epoxy treatment agent by the epoxy equivalent of the second epoxy material, is preferably 0.02 mol / 100 g or more and 0.25 mol / 100 g or less, and more preferably 0.08 mol / 100 g or more and 0.16 mol / 100 g or less, from the same viewpoint. From a similar viewpoint, the ratio of the molar content of the second epoxy group Y to the molar content of the first epoxy group X per 100 g of epoxy treatment agent (molar content of the second epoxy group Y / molar content of the first epoxy group X) is preferably 0.1 to 3, more preferably 0.2 to 1.5, and even more preferably 0.3 to 1. From a similar viewpoint, the molar content of the first epoxy group X is preferably equal to or greater than the molar content of the second epoxy group Y.

[0035] From the viewpoint of obtaining high filament convergence of the core wire 12, the content of the epoxy resin curing agent in the epoxy treatment agent is preferably 5% to 12% by mass, and more preferably 7% to 9% by mass.

[0036] The viscosity of the epoxy treatment agent is preferably 11 mPa·s to 30 mPa·s, more preferably 17 mPa·s to 25 mPa·s, and even more preferably 18 mPa·s to 24 mPa·s, from the viewpoint of obtaining high filament focusing of the core wire 12. The viscosity of this epoxy treatment agent is measured at a sample temperature of 25°C using a single cylindrical rotational viscometer in accordance with JIS Z8803:2011.

[0037] The heating temperature (set temperature in the heating furnace) after immersing the twisted yarn constituting the core wire 12 in the epoxy treatment agent and pulling it out is preferably 140°C to 180°C, more preferably 150°C to 170°C, from the viewpoint of obtaining high filament convergence of the core wire 12. The heating time is preferably 200 seconds to 400 seconds, more preferably 250 seconds to 350 seconds, from the same viewpoint.

[0038] From the viewpoint of obtaining high filament convergence of the core wire 12, the amount of solid material adhering to the twisted yarn by the epoxy treatment agent is preferably 15% to 25% by mass, and more preferably 18% to 20% by mass, relative to the mass of the core wire 12.

[0039] The twisted yarn constituting the core wire 12 may be subjected to a silane coupling agent treatment before epoxy treatment, in which it is immersed in a silane coupling agent solution, pulled out, and then heated. Examples of silane coupling agents include amino-based silane coupling agents, epoxy-based silane coupling agents, vinyl-based silane coupling agents, methacrylic acid-based silane coupling agents, mercapto and sulfa-based silane coupling agents, ureido-based silane coupling agents, isocyanate-based silane coupling agents, and the like.

[0040] The twisted yarn constituting the core wire 12 may be subjected to RFL treatment, in which, after epoxy treatment, it is immersed in an aqueous solution of resorcinol-formaldehyde latex (RFL), pulled out, and then heated. Examples of latex include vinylpyridine-styrene-butadiene rubber (Vp-SBR) latex, chloroprene rubber (CR) latex, and chlorosulfonated polyethylene rubber (CSM) latex.

[0041] The twisted yarn constituting the core wire 12 may be subjected to a rubber glue treatment, which involves immersing it in rubber glue, pulling it out, and then drying it, as necessary depending on its relationship with the rubber components of the rubber composition forming the belt body 11, after epoxy treatment or RFL treatment.

[0042] The reinforcing cloth 13 is provided so as to cover the surface of the belt body 11 on the side where a plurality of tooth part bodies 112 are provided. The tooth part 10A is configured such that each of the plurality of tooth part bodies 112 of the belt body 11 is covered with this reinforcing cloth 13. At the tooth bottom part 10B, the core wire 12 embedded in the inner peripheral side portion of the flat belt rubber part 111 of the belt body 11 is disposed immediately inside this reinforcing cloth 13.

[0043] The reinforcing cloth 13 is composed of, for example, a woven fabric, a knitted fabric, a non-woven fabric, etc. formed of yarns such as nylon fiber (aliphatic polyamide fiber), polyester fiber, aramid fiber (aromatic polyamide fiber), cotton, etc. The reinforcing cloth 13 preferably has elasticity, such as a woven fabric in which the weft yarn is subjected to woolly processing or the like. The reinforcing cloth 13 is preferably subjected to one or more than one adhesion treatment among an RFL treatment in which it is immersed in an RFL aqueous solution, pulled up, and then heated, a soaking treatment in which it is immersed in a low-viscosity rubber paste, pulled up, and then dried, and a coating treatment in which a high-viscosity rubber paste is applied to the surface on the side of the belt body 11 and dried for adhesion to the belt body 11. The reinforcing cloth 13 may be subjected to a base treatment in which it is immersed in an epoxy solution or an isocyanate solution and then heated before the adhesion treatment.

[0044] Next, a method for manufacturing the toothed belt B according to the embodiment will be described based on FIGS. 2 and 3A to C. The method for manufacturing the toothed belt B includes a material preparation step, a molding step, a crosslinking step, and a finishing step.

[0045] <Material Preparation Step> A predetermined rubber component is kneaded, and various rubber compounding agents are added thereto and kneaded to obtain an uncrosslinked rubber composition. Then, the obtained uncrosslinked rubber composition is subjected to calender molding or the like to produce an uncrosslinked rubber composition sheet 11'.

[0046] A contact treatment including an epoxy treatment is performed on the twisted yarns constituting the core wire 12. An adhesion treatment is performed on the reinforcing cloth 13. After the adhesion treatment, the reinforcing cloth 13 is formed into a cylindrical shape. <00000<Forming Process> Figure 2 shows the belt forming die 20. This belt forming die 20 is cylindrical and has an outer peripheral surface on which a plurality of tooth portion forming grooves 21 formed to extend in the axial direction are arranged at intervals in the circumferential direction.

[0048] As shown in Fig. 3A, a cylindrical reinforcing cloth 13 is placed on the outer peripheral surface of the belt forming die 20, and the core wire 12 is wound spirally thereon. Then, an unvulcanized rubber composition sheet 11' is wound thereon to form an unvulcanized slab S' on the belt forming die 20. The unvulcanized rubber composition sheet 11' is preferably provided such that the grain direction corresponds to the belt length direction.

[0049] <Crosslinking Process> As shown in Fig. 3B, a rubber sleeve 22 is placed on the unvulcanized slab S' on the belt forming die 20, and it is placed and sealed in a vulcanizing can. At the same time, the vulcanizing can is filled with high-temperature and high-pressure steam and held for a predetermined molding time. By pressing and heating the unvulcanized slab S' toward the belt forming die 20 in this way, the unvulcanized rubber composition sheet 11' is passed between the core wires 12 and the reinforcing cloth 13 is pressed while flowing into each of the plurality of tooth portion forming grooves 21 of the belt forming die 20 and crosslinked. At the same time, the core wire 12 and the reinforcing cloth 13 are integrally combined, and finally, as shown in Fig. 3C, a cylindrical belt slab S is molded.

[0050] <Finishing Process> The inside of the vulcanizing can is depressurized to release the seal, and the belt slab S molded between the belt forming die 20 and the rubber sleeve 22 is taken out and demolded, and cut into a predetermined width to obtain a toothed belt B according to an embodiment in which the cut surfaces of the core wires 12 are exposed on both side surfaces of the belt.

[0051] In the above embodiment, the toothed belt B is shown, but it is not particularly limited thereto, and it may be a friction transmission belt such as a flat belt, a narrow-edge V-belt, or a V-ribbed belt.

[0052] Also, in the above embodiment, the toothed belt B in which the belt body 11 is formed of a rubber composition is shown, but it is not particularly limited thereto, and it may be a transmission belt in which the belt body is formed of a resin composition such as a polyurethane resin.

[0053] (Core wire) Core wires for Examples 1 to 7 and Comparative Examples 1 to 2 were prepared. The composition of the epoxy treatment agent used in each is also shown in Table 1.

[0054] <Example 1> As the twisted yarn to make up the core wire, a single-ply yarn was prepared by twisting a bundle of 12,000 (12K) carbon fibers with a filament diameter of 7 μm in one direction.

[0055] The first epoxy material (Denacol EX-614B, manufactured by Nagase ChemteX, epoxy equivalent: 173, viscosity (25°C): 5000 mPa·s) mainly composed of sorbitol polyglycidyl ether (first epoxy compound, number of epoxy groups in the molecule: 4) is 49.58% by mass, the second epoxy material (Denacol EX-851, manufactured by Nagase ChemteX, epoxy equivalent: 150, viscosity (25°C): 30 mPa·s) mainly composed of polyethylene glycol diglycidyl ether with 2 ethylene glycol units (second epoxy compound, number of epoxy groups in the molecule: 2) is 4.25% by mass, and the imidazole-based epoxy resin curing agent (Curesol 2E4MZ-CN) containing 93% by mass of CN groups is 49.58% by mass, the first epoxy material (Denacol EX-614B, manufactured by Nagase ChemteX, epoxy equivalent: 173, viscosity (25°C): 5000 mPa·s) is 4.25% by mass, and the second epoxy material (Denacol EX-851, manufactured by Nagase ChemteX, epoxy equivalent: 150, viscosity (25°C): 30 mPa·s) is 93% by mass. A 60% by mass aqueous epoxy treatment agent was prepared by dissolving 6.63% by mass (active ingredient: 6.17% by mass) of Shikoku Chemicals Co., Ltd. in water. The ratio of the epoxy equivalent of the first epoxy material to the epoxy equivalent of the second epoxy material was 1.15, and the ratio of the viscosity of the first epoxy material to the viscosity of the second epoxy material was 167. In addition, an RFL aqueous solution using Vp-SBR latex was prepared.

[0056] A single-ply twisted yarn was subjected to two bonding treatments: epoxy treatment, which involved immersion in an epoxy treatment agent, followed by heating; and RFL treatment, which involved immersion in an RFL aqueous solution, followed by heating. The heating temperature for the epoxy treatment was 160°C and the heating time was 300 seconds. For the RFL treatment, the heating temperature was 200°C and the heating time was 300 seconds. The core wire of this bonded single-ply twisted yarn was designated as Example 1.

[0057] <Examples 2-7 and Comparative Examples 1-2> Example 2 had the same configuration as Example 1, except that the epoxy treatment agent used contained 46.47% by mass of a first epoxy material, 8.25% by mass of a second epoxy material, and 5.68% by mass of a 93% by mass epoxy resin curing agent (active ingredient: 5.28% by mass).

[0058] Example 3 had the same configuration as Example 1, except that the epoxy treatment agent used contained 40.95% by mass of a first epoxy material, 11.84% by mass of a second epoxy material, and 7.76% by mass of a 93% by mass epoxy resin curing agent (active ingredient: 7.22% by mass).

[0059] Example 4 had the same configuration as Example 1, except that the epoxy treatment agent used contained 27.66% by mass of a first epoxy material, 23.99% by mass of a second epoxy material, and 8.98% by mass of a 93% by mass epoxy resin curing agent (active ingredient: 8.35% by mass).

[0060] Example 5 had the same configuration as Example 1, except that the epoxy treatment agent used contained 22.54% by mass of a first epoxy material, 28.12% by mass of a second epoxy material, and 10.04% by mass of a 93% by mass epoxy resin curing agent (active ingredient: 9.34% by mass).

[0061] Example 6 had the same configuration as Example 1, except that the epoxy treatment agent used contained 18.01% by mass of a first epoxy material, 31.70% by mass of a second epoxy material, and 11.07% by mass of a 93% by mass epoxy resin curing agent (active ingredient: 10.30% by mass).

[0062] Example 7 had the same configuration as Example 1, except that the epoxy treatment agent used contained 14.02% by mass of a first epoxy material, 36.46% by mass of a second epoxy material, and 10.24% by mass of a 93% by mass epoxy resin curing agent (active ingredient: 9.52% by mass).

[0063] Comparative Example 1 had the same configuration as Example 1, except that the epoxy treatment agent used contained 53.90% by mass of the first epoxy material and 6.56% by mass of a 93% by mass epoxy resin curing agent (active ingredient: 6.10% by mass).

[0064] Comparative Example 2 had the same configuration as Example 1, except that the epoxy treatment agent used contained 50.17% by mass of the second epoxy material and 10.57% by mass of a 93% by mass epoxy resin curing agent (active ingredient: 9.83% by mass).

[0065]

[0066] (Evaluation of Fuzz Resistance) For each of Examples 1 to 7 and Comparative Examples 1 to 2, a test specimen was prepared in which a core wire was embedded in the surface layer of one end of an elongated rubber sheet made of a rubber composition, extending along the length, with the side surface of the core wire exposed. The core wire exposed on the surface of the test specimen was then rubbed with a metal piece. A rating was given to specimens in which the carbon fiber filament bundles were integrally bundled and no fuzzing was observed at all, a B rating was given to specimens in which the carbon fiber filament bundles were partially separated and slight fuzzing was observed, and a C rating was given to specimens in which the carbon fiber filament bundles did not bundle together and significant fuzzing was observed. The evaluation results are shown in Table 1.

[0067] The present invention is useful in the field of power transmission belts, methods for manufacturing the same, and core wires and epoxy treatment agents used therein.

[0068] B Toothed belt S' Uncrosslinked slab S Belt slab 10A Tooth portion 10B Tooth base portion 11 Belt body 11' Uncrosslinked rubber composition sheet 111 Flat rubber strip portion 112 Tooth rubber portion 12 Core wire 13 Reinforcement fabric 20 Belt molding die 21 Tooth forming groove 22 Rubber sleeve

Claims

1. A power transmission belt in which a core wire made of twisted yarn is embedded in the belt body, wherein the twisted yarn constituting the core wire is subjected to epoxy treatment by being immersed in an epoxy treatment agent containing a first epoxy material mainly composed of a first epoxy compound having three or more epoxy groups in its molecule, and a second epoxy material mainly composed of a second epoxy compound having two or fewer epoxy groups in its molecule, then pulled out and heated.

2. A transmission belt according to claim 1, wherein the epoxy equivalent of the first epoxy material is 160 g or more and 180 g or less, and the epoxy equivalent of the second epoxy material is 120 g or more and 170 g or less.

3. A transmission belt according to claim 1 or 2, wherein the epoxy equivalent of the first epoxy material is higher than the epoxy equivalent of the second epoxy material, and the ratio of the epoxy equivalent of the first epoxy material to the epoxy equivalent of the second epoxy material is 1.05 or more and 1.5 or less.

4. A power transmission belt according to any one of claims 1 to 3, wherein the viscosity of the first epoxy material is 1,000 mPa·s or more and 10,000 mPa·s or less, the viscosity of the second epoxy material is 10 mPa·s or more and 100 mPa·s or less, and the viscosity of the epoxy treatment agent is 11 mPa·s or more and 30 mPa·s or less.

5. A transmission belt according to any one of claims 1 to 4, wherein the viscosity of the first epoxy material is higher than the viscosity of the second epoxy material, and the ratio of the viscosity of the first epoxy material to the viscosity of the second epoxy material is 100 or more and 250 or less.

6. A power transmission belt according to any one of claims 1 to 5, wherein the molar content of the first epoxy group, obtained by dividing the content of the first epoxy material per 100 g of epoxy treatment agent by the epoxy equivalent of the first epoxy material, is 0.05 mol / 100 g or more and 0.3 mol / 100 g or less, and the molar content of the second epoxy group, obtained by dividing the content of the second epoxy material per 100 g of epoxy treatment agent by the epoxy equivalent of the second epoxy material, is 0.02 mol / 100 g or more and 0.25 mol / 100 g or less.

7. A power transmission belt according to any one of claims 1 to 6, wherein the ratio of the molar content of epoxy groups of the second epoxy material to the molar content of epoxy groups of the first epoxy material per 100 g of epoxy treatment agent is 0.1 or more and 3 or less.

8. A power transmission belt according to any one of claims 1 to 7, wherein the first epoxy compound comprises sorbitol polyglycidyl ether.

9. A power transmission belt according to any one of claims 1 to 8, wherein the second epoxy compound comprises polyethylene glycol diglycidyl ether.

10. A transmission belt according to any one of claims 1 to 9, wherein the mass ratio of the content of the first epoxy material in the epoxy treatment agent to the content of the second epoxy material is 20 / 80 or more and 95 / 5 or less.

11. A power transmission belt according to any one of claims 1 to 10, wherein the twisted yarn constituting the core wire is subjected to RFL treatment, which involves immersing it in a resorcinol-formaldehyde-latex aqueous solution, pulling it out, and then heating it after the epoxy treatment.

12. A power transmission belt according to any one of claims 1 to 11, wherein the twisted yarn constituting the core wire is made of carbon fiber.

13. A method for manufacturing a power transmission belt in which a core wire made of twisted yarn is embedded in the belt body, comprising the step of immersing the twisted yarn constituting the core wire in an epoxy treatment agent containing a first epoxy material mainly composed of a first epoxy compound having three or more epoxy groups in its molecule and a second epoxy material mainly composed of a second epoxy compound having two or fewer epoxy groups in its molecule, then removing it and heating it.

14. A core wire made of twisted yarn embedded in the belt body of a power transmission belt, wherein the twisted yarn constituting the core wire is subjected to epoxy treatment by being immersed in an epoxy treatment agent containing a first epoxy material mainly composed of a first epoxy compound having three or more epoxy groups in its molecule, and a second epoxy material mainly composed of a second epoxy compound having two or fewer epoxy groups in its molecule, then pulled out and heated.

15. An epoxy treatment agent used for epoxy treatment applied to the twisted yarn constituting the core wire embedded in the belt body of a power transmission belt, comprising a first epoxy material mainly composed of a first epoxy compound having three or more epoxy groups in its molecule, and a second epoxy material mainly composed of a second epoxy compound having two or fewer epoxy groups in its molecule.

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