JP2022171350A - Synchronous belt - Google Patents

Abstract

To provide a toothed belt 10 that has excellent flexural fatigue resistance and suitable for high load transmission.SOLUTION: A toothed belt 10 has a belt body 11 having a back rubber part 11a and a tooth rubber part 11b both of which are composed of a thermoplastic elastomer composition, and a core wire 13 buried in the back rubber part 11a. The thermoplastic elastomer composition comprises an elastomer component that is polyamide thermoplastic elastomer or polyester thermoplastic elastomer. The back rubber part 11a has hardness of 25-70. The tooth rubber part 11b has hardness of 40-70, which is greater than or equal to the hardness of the back rubber part 11a. The core wire 13 has yarn 16 coated with an adhesive coating layer 21 composed of an adhesive. The yarn 16 includes multiple filaments 18. The multiple filaments 18 include a carbon filament composed of a carbon fiber.SELECTED DRAWING: Figure 1

Description

The present invention relates to toothed belts.

Conventionally, rubber belts and cast urethane belts are known as toothed belts. Each of these belts has a back rubber portion, a large number of tooth rubber portions integrally provided on the back rubber portion at a predetermined pitch in the longitudinal direction of the belt, and a belt between the back rubber portion and the tooth rubber portion. core wires extending in the longitudinal direction and embedded at a predetermined pitch in the width direction of the belt. Both are different in that the back rubber portion and tooth rubber portion are molded from vulcanized rubber or cast urethane.

These belts require a vulcanization process and a post-vulcanization process in the manufacturing process, and therefore have low productivity. Further, these belts have the problem that post-processing such as shaping after belt molding is difficult due to the properties of vulcanized rubber and cast urethane, and recycling is also difficult.

As a toothed belt capable of solving such problems, a toothed belt in which a back rubber portion and a tooth rubber portion are formed of a thermoplastic elastomer has also been proposed (see, for example, Patent Documents 1 and 2).

JP-A-7-27178 JP-A-10-2379

A toothed belt in which a thermoplastic elastomer is used to form the back rubber portion and the tooth rubber portion has a problem that the teeth of the belt tend to deform when the load applied to the belt increases. Furthermore, when the rotation speed of the pulley on which the belt is hung increases, the belt generates heat, and in this case also, there is a problem that the teeth of the belt are easily deformed.

Carbon fibers are less likely to be deformed by creep than organic fibers. Therefore, by adopting a yarn made of carbon fiber as the core wire, the toothed belt can suppress a decrease in tension due to use. This toothed belt has the prospect of long-term use.
In Patent Document 2 mentioned above, a yarn containing a filament made of carbon fiber (hereinafter referred to as carbon filament) is employed as the core wire.
In Patent Document 2, before twisting, the filaments contained in the yarn are subjected to adhesion treatment with the same thermoplastic elastomer as the back rubber portion and tooth rubber portion, but the yarn is subjected to adhesion treatment. is not applied. As a result, the yarn may separate from the belt body, and the toothed belt may not be able to maintain a state suitable for high-load transmission over a long period of time.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a toothed belt suitable for high-load transmission.

(1) The toothed belt of the present invention comprises a flat belt-like back rubber portion and a plurality of belt teeth disposed on the inner peripheral side of the back rubber portion and integrally provided with the back rubber portion to form belt teeth. and a belt main body in which both the back rubber portion and the tooth rubber portion are made of a thermoplastic elastomer composition; and a tooth portion covering material covering the plurality of tooth rubber portions provided on the inner peripheral side of the belt body, the thermoplastic elastomer composition is a thermoplastic polyamide elastomer (TPAE) or a thermoplastic polyester elastomer (TPC), the thermoplastic elastomer composition constituting the back rubber portion has a hardness of 25 to 70, and the tooth rubber The hardness of the thermoplastic elastomer composition composing the portion is 40 to 70 and is equal to or higher than the hardness of the thermoplastic elastomer composition composing the back rubber portion, and the core wire is an adhesive coating made of an adhesive. A yarn covered with a layer is provided, said yarn comprising a multitude of filaments, said multitude of filaments comprising carbon filaments made of carbon fibers.

In the toothed belt, the back rubber portion and the tooth rubber portion are made of a composition containing thermoplastic polyamide elastomer (TPAE) or thermoplastic polyester elastomer (TPC) as an elastomer component. Therefore, no vulcanization step or post-vulcanization step is required in the manufacturing process, and the toothed belt is excellent in productivity. In addition, the elastomer component is resistant to heat, and the elastic modulus does not decrease even when the belt is driven at a high load or at a high rotational speed. As a result, deformation is less likely to occur when the belt is driven, and problems such as tooth jumping caused by deformation of the tooth rubber portion are less likely to occur. This toothed belt is suitable for high load transmission.

Further, in the toothed belt, the thermoplastic elastomer composition constituting the back rubber portion and the tooth rubber portion each has a specific hardness. As a result, the belt is too soft and deforms when subjected to power, resulting in chipping of teeth, or the belt is too hard and is damaged when wound around pulleys, or cracks occur on the back of the belt during driving. Suppressed.
In the above toothed belt, the yarns forming the cords contain carbon filaments. Since the elastic modulus of the carbon filaments is high, even if a high load is applied to the toothed belt, deformation is unlikely to occur, and engagement with the pulleys is unlikely to shift. As a result, it is possible to prevent the belt from running over the pulley due to misengagement between the belt and the pulley, and the loss of belt teeth due to localized force applied to the belt. In addition, since carbon filaments do not have the creep property of filaments made of organic fibers, the toothed belt is very difficult to stretch and the tension of the toothed belt is less likely to decrease.
Since the yarn is covered with the adhesive coating layer, the yarn is strongly adhered to the back rubber portion and the tooth rubber portion (that is, the belt body) through the adhesive coating layer. Even if the boundary between the yarn and the belt body is distorted when the belt is driven, the yarn is prevented from peeling off from the belt body.
The adhesive coating layer constrains the filaments contained in the yarn, thereby suppressing filament movement. Since the friction of the carbon filaments is suppressed, the reduction in strength of the core wire due to wear of the carbon filaments is prevented.
This toothed belt maintains a state suitable for high-load transmission over a long period of time.

(2) In the toothed belt, the elastomer component of the thermoplastic elastomer composition is preferably thermoplastic polyamide elastomer (TPAE). TPAE is suitable as a material for composing the tooth rubber portion and the back rubber portion of the toothed belt because of its small energy loss against dynamic deformation, little heat generation due to bending, and excellent chemical resistance.

(3) In the toothed belt, the adhesive preferably contains an epoxy group-containing compound and a curing agent and has a solid content ratio of 80% by mass or more. In this case, the yarn is firmly adhered to the belt body via the adhesive coating layer, so the yarn is prevented from peeling off from the belt body. Since the movement of the filament is suppressed, the reduction in strength of the core wire due to wear of the carbon filament is prevented.

(4) In the toothed belt, the curing agent is preferably a radical initiator. In this case, the curing agent enhances the adhesion between the yarn and the belt body. In particular, when the elastomer component of the thermoplastic elastomer composition is TPAE, the reaction between the carbon filaments and TPAE is promoted, and the bonding strength between the yarn and the belt body is dramatically improved. In this toothed belt, the yarn is prevented from being detached from the belt body. Since the movement of the filament is suppressed, the reduction in strength of the core wire due to wear of the carbon filament is prevented.

(5) In the toothed belt, the adhesive may contain resorcin and formaldehyde and have a solid content ratio of 80% by mass or more. Even in this case, the yarn is firmly adhered to the belt body through the adhesive coating layer, so the yarn is prevented from peeling off from the belt body. Since the movement of the filament is suppressed, the reduction in strength of the core wire due to wear of the carbon filament is prevented. Compared to the case where a solution containing an epoxy group-containing compound and a curing agent is used as an adhesive, a soft adhesive coating layer is formed, so that the core wire is easily bent. Therefore, even if this toothed belt is used for a pulley with a small pulley diameter that causes a large strain in the core wire, the core wire is less likely to be cut.

(6) In the toothed belt, the soft segment of the thermoplastic polyamide elastomer (TPAE) preferably has a polyether structure. In this case, this TPAE tends to exhibit rubber elasticity at room temperature. Therefore, it is possible to prevent the belt from being damaged when wound around the pulley, and from cracking on the back surface of the belt during driving.
With this toothed belt, a state suitable for high-load transmission is maintained over a long period of time.

ADVANTAGE OF THE INVENTION According to this invention, the toothed belt suitable for high-load transmission is obtained.

It is a perspective view showing typically a part of toothed belt concerning one embodiment of the present invention. It is a front view of arrow X in FIG. FIG. 2 is an end view taken along line AA of FIG. 1; FIG. 2 is a cross-sectional view showing an example of yarn; FIG. 4 is a partial cross-sectional view of a belt mold used for manufacturing toothed belts; It is a figure explaining the manufacturing process of a toothed belt. It is a figure explaining the manufacturing process of a toothed belt. It is a figure explaining the manufacturing process of a toothed belt. It is a figure which shows the pulley layout in the 1st running test. It is a figure which shows the pulley layout in a 2nd running test.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. The invention is not limited to these embodiments.
FIG. 1 is a perspective view showing part of a toothed belt 10 according to an embodiment of the invention. 2 is a front view of arrow X in FIG. 1. FIG. FIG. 3 is an end view taken along line AA of FIG. 1. FIG.

<Toothed belt>
The toothed belt 10 is an endless meshing transmission belt.
A portion of the toothed belt 10 is shown in FIG.
The toothed belt 10, as shown in FIG. 1, includes a belt body 11, cords 13, and a reinforcing cloth 14 as a tooth covering material.

The dimensions of the toothed belt 10 are not particularly limited and can be selected according to the design.
The dimensions of the toothed belt 10 are, for example, a belt circumference (belt length on the belt pitch line BL) of 54 mm or more and 6600 mm or less, a belt width of 3 mm or more and 340 mm or less, and a belt maximum thickness of 1.3 mm or more and 13.2 mm or less. can be

A plurality of belt teeth 12 are arranged on the inner peripheral side of the toothed belt 10 at predetermined intervals. The tooth profile of the belt teeth 12 is an S tooth profile.
In the embodiment of the present invention, the tooth profile of the belt teeth 12 is not limited to the S tooth profile, and may be an arc tooth profile other than the S tooth profile, a trapezoidal tooth profile, or any other tooth profile. may

In the toothed belt 10, the belt teeth 12 are straight teeth extending parallel to the belt width direction. In the embodiment of the present invention, the belt teeth 12 may be helical teeth extending in a direction inclined with respect to the belt width direction.

In the toothed belt 10, the tooth pitch P (see P in FIG. 3) of the belt teeth 12 is, for example, 2 mm or more and 20 mm or less.
The tooth height of the belt tooth 12 is defined by the dimension from the tooth bottom 15 between a pair of belt teeth 12 adjacent to each other in the belt length direction to the tip of the belt tooth 12 (see H in FIG. 3). It is 0.76 mm or more and 8.4 mm or less.
Further, the toothed belt 10 has, for example, the number of teeth of 27 or more and 560 or less, a tooth width (lengthwise dimension of the belt) of, for example, 1.3 mm or more and 15.0 mm or less, and a PLD of, for example, 0.254 mm or more. 159 mm or less.
These belt tooth dimensions are exemplary and not intended to be limiting in these ranges.

<belt body>
The belt body 11 has an endless flat belt-shaped back rubber portion 11a and a plurality of tooth rubber portions 11b. A plurality of tooth rubber portions 11 b are provided on the inner peripheral side of the belt body 11 . Specifically, the plurality of tooth rubber portions 11b are integrally provided on the inner peripheral side, which is one side of the back rubber portion 11a, at intervals in the lengthwise direction of the belt.
In the belt body 11, each of the back rubber portion 11a and the tooth rubber portion 11b is made of a thermoplastic elastomer composition. The thermoplastic elastomer composition forming the back rubber portion 11a and the thermoplastic elastomer composition forming the tooth rubber portion 11b may be the same or different.

In the present invention, the thermoplastic elastomer composition refers to a composition containing a thermoplastic elastomer component as an essential component and optionally containing various additives other than the elastomer component.
The thermoplastic elastomer composition may contain only the elastomer component.

The elastomer component of the thermoplastic elastomer composition forming the belt body 11 is thermoplastic polyamide elastomer (TPAE) or thermoplastic polyester elastomer (TPC).
TPAE and TPC are more resistant to heat than other thermoplastic elastomers such as olefinic, styrene, and urethane elastomers, and their elastic modulus is less likely to decrease even at belt temperatures during high-load driving or high-speed rotational driving. Therefore, deformation of the tooth rubber portion 11b due to heat generated by the belt is less likely to occur during high-load driving or high-speed rotational driving.

As the elastomer component, a polyamide-based thermoplastic elastomer (TPAE) is preferable.
TPAE has less energy loss in dynamic deformation and less heat generation due to bending than TPC. Therefore, the belt temperature during driving is relatively low, making it suitable for high-load and high-speed power transmission.
TPAE also has excellent chemical resistance. Therefore, it is suitable for use in applications where contact with chemicals is expected, for example, for toothed belts used in industrial machinery equipped with a hydraulic system, driving parts of two-wheeled vehicles, and electric seats of passenger cars.

The thermoplastic polyester elastomer (TPC) is a block copolymer that employs a polyester structure such as polybutylene terephthalate (PBT) as the hard segment and polyether, polyester, or polycarbonate as the soft segment.

The thermoplastic polyamide elastomer (TPAE) is a block copolymer having polyamide (nylon) as a hard segment and polyol as a soft segment.
Examples of the polyamide (nylon) include nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612, and nylon 1212. Among these, nylon 11 and nylon 12 are preferred because they have a low amide bond content and are less susceptible to dimensional change.

As the polyol, one or both of polyester polyol and polyether polyol can be employed.
When polyester polyol and polyether polyol are compared, it is easy to exhibit rubber elasticity at room temperature without blending a plasticizer, and cracks are less likely to occur when the belt is bent. is preferred. In this case, the soft segment has a polyether structure.
Further, when polyether polyol is used as the polyol component of TPAE, it is not necessary to blend a plasticizer, and the tooth rubber portion 11b and the back rubber portion 11a are made of a thermoplastic elastomer composition that does not contain a plasticizer. In the toothed belt 10 configured with , the plasticizer does not volatilize and adhere to equipment and products. Therefore, such toothed belt 10 can be suitably used in a clean room.

Examples of the polyester polyol include polyethylene adipate and polybutylene adipate.
Examples of the polyether polyols include polytetramethylene ether glycol and polyoxypropylene glycol.

Commercially available products may be used as the thermoplastic polyester elastomer and the thermoplastic polyamide elastomer.
Examples of commercially available polyester thermoplastic elastomers include the Hytrel (registered trademark) series manufactured by DuPont-Toray.
Commercially available products of the thermoplastic polyamide elastomer include, for example, PEBAX (registered trademark) series manufactured by Arkema, VESTAMID (registered trademark) series and DAIAMID (registered trademark) series manufactured by Daicel-Evonik, and EMS Grillflex (registered trademark) series can be exemplified.

The thermoplastic elastomer composition that constitutes the back rubber portion 11a and the tooth rubber portion 11b may contain short fibers, whiskers, fillers, colorants, antistatic agents, flame retardants, short fibers, whiskers, fillers, colorants, as needed, in addition to elastomer components such as TPAE and TPC. Additives such as retardants, antioxidants, UV absorbers, light stabilizers, hydrolysis inhibitors, plasticizers, lubricants, preservatives, antifungal agents, solid lubricants, lubricating oils, and greases good.

On the other hand, when these additives are contained, these additives may detach from the back rubber portion 11a and the tooth rubber portion 11b and contaminate the usage environment. Therefore, when the toothed belt 10 is, for example, a toothed belt used in a clean room, the thermoplastic elastomer composition preferably does not contain the above additives and is composed only of elastomer components.

In the belt body 11, the thermoplastic elastomer composition forming the back rubber portion 11a has a hardness of 25-70. The hardness of the thermoplastic elastomer composition forming the tooth rubber portion 11b is 40-70. The hardness of the thermoplastic elastomer composition forming the tooth rubber portion 11b is greater than or equal to the hardness of the thermoplastic elastomer composition forming the back rubber portion 11a.

The hardness of the thermoplastic elastomer composition is measured at 23° C. using a type D durometer according to JIS K6253-3. This hardness is also called Shore D hardness.

Hereinafter, in the present specification, the hardness of the thermoplastic elastomer composition forming the back rubber portion 11a is also referred to simply as the "back rubber portion hardness", and the hardness of the thermoplastic elastomer composition forming the tooth rubber portion 11b. The hardness is also simply referred to as "tooth rubber portion hardness".

In the toothed belt having such a structure, the hardness of the back rubber portion is within the above range and less than the hardness of the tooth rubber portion, so that it may be damaged when wound around a pulley, or cracks may occur on the back surface of the belt during driving. To be restrained from occurring or to occur. Further, since the hardness of the tooth rubber portion is equal to or higher than the hardness of the back rubber portion and is within the above range, the teeth of the belt are less likely to be worn during use, and deformation of the belt teeth is less likely to occur.
The hardness of the thermoplastic elastomer composition forming the back rubber portion 11a may be lower than the hardness of the thermoplastic elastomer composition forming the tooth rubber portion 11b.

The difference between the hardness of the tooth rubber portion and the hardness of the back rubber portion is preferably 5 or more, more preferably 10 or more. It is more suitable for suppressing the occurrence of back surface cracks.

In the toothed belt 10, it is also preferable that the hardness of the back rubber portion is 25-50 and the hardness of the tooth rubber portion is 45-65. In this case, it is suitable for simultaneously suppressing the generation of back surface cracks and suppressing the deformation of the belt teeth.

The hardness of the back rubber portion is determined by the molecular weight of the elastomer component contained in the thermoplastic elastomer composition that constitutes the back rubber portion 11a, the ratio of the hard segment to the soft segment, and the addition of components other than the elastomer component contained in the thermoplastic elastomer composition. It can be controlled by adjusting the type and amount of the agent.
Similarly, the hardness of the tooth rubber portion can be controlled by the elastomer component contained in the thermoplastic elastomer composition constituting the tooth rubber portion 11b and additives other than the elastomer component.

<Reinforcing cloth>
The reinforcing cloth 14 is attached so as to cover the surface of the belt body 11 on the inner peripheral side where the plurality of tooth rubber portions 11b are provided. Accordingly, the tooth rubber portion 11b of each belt tooth 12 is covered with the reinforcing cloth 14. As shown in FIG.
This prevents direct contact between the thermoplastic elastomer composition forming the tooth rubber portion 11b and the pulley. Therefore, wear of the tooth rubber portion 11b can be suppressed.
The thickness of the reinforcing cloth 14 is, for example, 0.1 mm or more and 2.5 mm or less.

The reinforcing cloth 14 is made of a fibrous member such as a woven cloth, a knitted cloth, a nonwoven cloth, a resin film, or the like.
Examples of yarns for forming the fiber member include nylon fibers (polyamide fibers), polyester fibers, aramid fibers, polyparaphenylenebenzobisoxazole (PBO) fibers, and cotton.
Examples of materials for the resin film include nylon (polyamide) and polyester.

Among these, a fibrous member formed mainly of nylon fibers and a nylon film (hereinafter, both are collectively referred to as a nylon reinforcing cloth) are preferable.
Here, having nylon fibers as a main component means that the amount of nylon fibers contained in all fibers is 50% by mass or more.
Since the nylon reinforcing cloth has a low coefficient of friction, the frictional energy is small and it is hard to wear.
In addition, since the nylon reinforcing cloth has a high melting point, even if the temperature of the contact portion with the pulley rises, the nylon reinforcing cloth is unlikely to be melted and rapidly worn.
The reinforcing cloth 14 may be, for example, a stretchable cloth such as a woven cloth whose wefts are woolly processed.

The reinforcement cloth 14 is subjected to, for example, an RFL treatment in which the reinforcement cloth 14 is immersed in an RFL aqueous solution and then heated as an adhesion treatment for increasing the adhesive strength with the belt body 11 .
Prior to the bonding treatment, the reinforcing cloth 14 may be subjected to a base treatment in which it is immersed in an epoxy solution or an isocyanate solution and then heated.

The reinforcing cloth 14 may contain a granular wear modifier such as PTFE (polytetrafluoroethylene) particles, ultra-high molecular weight polyethylene particles (for example, an average molecular weight of 1 million or more) on its surface or inside. good.
When the reinforcing cloth 14 contains a wear modifier, deformation due to wear of the tooth rubber portion 11b is further suppressed.

The wear modifier may be dispersed in the above-mentioned RFL aqueous solution in advance, and may be incorporated into the reinforcing fabric 14 by performing a treatment using this RFL aqueous solution.

Further, when the reinforcing cloth 14 is made of a resin film, the abrasion modifier may be contained in the reinforcing cloth 14 by dispersing the abrasion modifier in advance in the resin film.

<Core wire>
The core wire 13 is embedded in the inner peripheral portion of the back rubber portion 11a of the belt body 11 so as to form a spiral having a pitch in the width direction of the belt.
The outer diameter of the core wire 13 is, for example, 0.45 mm or more and 3.0 mm or less.
The pitch of the cords 13 (arrangement pitch in the belt width direction) is, for example, 0.5 mm or more and 4.0 mm or less.
The core 13 of this toothed belt 10 is provided with yarns 16 .

FIG. 4 is a cross-sectional view showing an example of the yarn 16. As shown in FIG. Yarn 16 includes a number of filaments 18 . In this toothed belt 10, all or part of the filaments 18 included in the yarn 18 are carbon filaments made of carbon fibers. The numerous filaments 18 that make up the yarn 18 contain carbon filaments.
The filament diameter of the carbon filament is, for example, 5 μm or more and 7 μm or less. The number of carbon filaments included in the yarn 16 is, for example, 3000 or more. The upper limit of the number of filaments is not particularly limited, and is, for example, 96,000.

Carbon filaments include, for example, PAN-based carbon filaments and pitch-based carbon filaments. A PAN-based carbon filament is preferable as the carbon filament because of its flexibility.

As described above, the yarns 16 that make up the cord 13 include carbon filaments. Since the elastic modulus of the carbon filaments is high, even if a high load is applied to the toothed belt 10, deformation is unlikely to occur, and engagement with the pulleys is unlikely to shift. Therefore, it is possible to prevent the toothed belt 10 from riding on the pulley due to the meshing between the toothed belt 10 and the pulley being deviated, or the belt tooth 12 being chipped due to local force being applied to the toothed belt 10.例文帳に追加can be done. In addition, since the carbon filaments do not have the creep property of the filaments 18 made of organic fibers, the toothed belt 10 is very difficult to stretch and the tension of the toothed belt 10 does not easily decrease.

The yarn 16 shown in FIG. 4 includes five strands 17, each strand 17 including multiple filaments 18. In this yarn 16, all or part of the filaments 18 included in the strand 17 are carbon filaments.
In making this yarn 16 , a number of filaments 18 are twisted together to form a strand 17 . Yarn 16 is formed by twisting five strands 17 together. This yarn 16 has two layers of twist consisting of a ply and a ply.
Although not shown, the yarn 16 may be configured to have three layers of twist, consisting of a base twist, a middle twist and a top twist. The yarn 16 may be a single-twisted yarn obtained by single-twisting a large number of filaments 18 .

In this toothed belt 10, the cord 13 can comprise yarns 16 having two or more layers of twist. In this case, since the yarn 16 has two or more layers of twist, the strain induced in the filament 18 is less than that of the above-described single-twisted yarn having a single layer of twist, even for the same strength of twist. Since the compressive strain on the surface of the yarn 16 is kept small, the filament 18 is less likely to break even when the yarn 16 is bent. Since the carbon filaments are difficult to cut, the toothed belt 10 prevents the core wires 13 from being cut due to bending fatigue. From this point of view, cord 13 preferably comprises yarn 16 having two or more layers of twist.

When the yarn 16 has two layers of twist, a plurality of strands 17 obtained by under-twisting a large number of filaments 18 in one direction (direction of S twist or direction of Z-twist) are gathered and twisted in the direction of the first twist. A strand 17 obtained by twisting a large number of filaments 18 in one direction (S-twisting direction or Z-twisting direction). The yarn 16 may be twisted by a so-called Lang twist, in which a plurality of yarns are collected and ply twisted in the same direction as the first twist.

If the yarn 16 has two or more layers of twist, then in the yarn 16, the sum of the twist factors at each layer of twist (e.g., for the yarn 16a shown in FIG. ) is preferably greater than 30 and 120 or less. If the yarn 16 is a single-twisted yarn, it preferably has a twist coefficient of 30 or more and 120 or less.

By setting the total twist factor greater than 30, the strength of the yarn 16 is increased. The cord 13 including this yarn 16 has an appropriate strength and can effectively contribute to high load transmission.
By setting the total twist factor to 120 or less, the distortion caused in the filaments 18 by twisting is reduced. Carbon filament breakage due to excessive twisting is prevented. Therefore, the core wire 13 is less likely to break due to bending fatigue.

For yarns 16 having two or more layers of twist, the ply twist preferably has a twist factor of 100 or less. In this case, breakage of the carbon filaments due to excessive twisting is prevented. Therefore, the core wire 13 is less likely to break due to bending fatigue. From this point of view, the twist coefficient of the ply twist is more preferably 60 or less. From the viewpoint that the core wire 13 has an appropriate strength and can effectively contribute to high-load transmission, the twist coefficient of the ply twist is preferably 30 or more.

As shown in FIG. 4, if the yarn 16 has two layers of twist, the twist factor of the bottom twist may be the same as the twist factor of the top twist, and the twist factor of the bottom twist is equal to the twist factor of the top twist. may be different from

If the yarn 16 has three layers of twist, even if the sum of the twist factor of the first twist and the twist factor of the middle twist (hereinafter referred to as the total twist factor of the first twist and the middle twist) is the same as the twist factor of the top twist. Well, the total twist factor of the ply twist and the middle twist may be different from the twist factor of the ply twist.
In the yarn 16 having three layers of twist, the ratio of the twist coefficient of the first twist to the total twist coefficient of the first twist and the middle twist is 5% or more from the viewpoint of effectively reducing the strain generated in the filament 18 by twisting. It is preferably 30% or less.

Regarding the above-mentioned twist coefficient, the twist coefficient is K, the number of twists per unit length is T (twists/m), and the fineness of the fiber bundle (yarn 16 or strand 17) to be twisted is D (dtex). is represented by the following formula (1).
K=T×√D/100 (1)
For example, when the yarn 16 has two layers of twist, the fineness of the strand 17 obtained by the first twist is used as the fineness D of the fiber bundle to be twisted in calculating the twist coefficient K of the first twist. In calculating the twist coefficient K of the ply twist, the fineness of the yarn 16 obtained by the ply twist is used as the fineness D of the fiber bundle to be twisted.

In this toothed belt 10, as shown in FIG. 2, the surface of the yarns 16 included in the cord 13 is covered with an adhesive coating layer 21 made of adhesive. The cord 13 comprises yarns 16 and an adhesive coating layer 21 covering the yarns 16 .

Yarn 16 is coated with an adhesive coating layer 21 . The yarn 16 is firmly adhered to the back rubber portion 11a and the tooth rubber portion 11b (that is, the belt body 10) via the adhesive coating layer 21. As shown in FIG. Therefore, even if the boundary portion between the yarn 16 and the belt body 10 is distorted when the belt is driven, the yarn 16 is prevented from peeling off from the belt body 10 .
Since the adhesive coating layer 21 constrains the filaments 18 contained in the yarn 16, movement of the filaments 18 is restrained. Since the friction of the carbon filaments is suppressed, the reduction in strength of the core wire 13 due to wear of the carbon filaments is prevented.
The toothed belt 10 maintains a state suitable for high-load transmission over a long period of time.

In this toothed belt 10, an emulsion in which an epoxy group-containing compound and a curing agent are dispersed in water can be used as the adhesive for the adhesive coating layer 21. FIG.

In this toothed belt 10, the adhesive for the adhesive coating layer 21 contains an epoxy group-containing compound and a curing agent as a main agent, and the solid content ratio of this main agent is preferably 80% by mass or more. As a result, the yarn 16 is firmly adhered to the belt body 10 via the adhesive coating layer 21, so that the yarn 16 is prevented from peeling off from the belt body 10. Since the movement of the filament 18 is suppressed, the reduction in strength of the core wire 13 due to wear of the carbon filament is prevented. The solid content ratio of the main agent is represented by the ratio of the mass of the main agent to the total mass of solid content obtained by drying the adhesive. The same applies to the solid content ratio of the main agent in the sizing agent described later.

Examples of epoxy group-containing compounds include sorbitol polyglycidyl ether, glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolpropane polyglycidyl ether, and the like. Among these, polyglycerol polyglycidyl ether is preferred.

Examples of curing agents include radical initiators, isocyanate curing agents, amine curing agents, and the like.
Examples of radical initiators include 2,2′-azobis(isobutyronitrile) (AIBN), 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) (V-70), 2 , 2'-azobis (2,4-dimethylvaleronitrile) (V-65), 1,1'-azobis (cyclohexane-1-carbonitrile) (V-40) and other azonitrile compounds, 2,2'-azobis Azoamidine compounds such as [2-(2-imidazolin-2-yl)propane] (VA-061), 2,2′-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] (VA-086) ), azoamide compounds such as 2,2'-azobis (N-butyl-2-methylpropionamide) (VAm-110), azo polymerization containing azo groups such as 4,4'-azobis (4-cyanovaleric acid) Initiators; persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate; inorganic peroxides such as hydrogen peroxide; t-butylperoxyneoheptanoate, t-hexylperoxyneoheptanoate, di-t -Organic peroxides such as butyl peroxide, benzoyl peroxide, cumene hydroperoxide, and t-butyl hydroperoxide; redox polymerization combining organic peroxides with reducing agents such as sodium sulfite, Rongalite, and ascorbic acid initiators and the like.
Examples of isocyanate curing agents include naphthalene diisocyanate, isophorone diisocyanate, 4,4′-diphenylmethane diisocyanate, toluene-2,4-diisocyanate, xylylene diisocyanate, tolylene diisocyanate, polymethylene polyphenyl diisocyanate, hexamethylene diisocyanate, and the like. mentioned.
Examples of amine-based curing agents include imidazole-based compounds, diamine compounds, compounds having an oxazole ring, and the like.

In this toothed belt 10, the curing agent for the adhesive is preferably a radical initiator. In this case, the hardening agent enhances the adhesion between the yarn 16 (specifically, the filament 18) and the belt body 11. In particular, when the elastomer component of the thermoplastic elastomer composition is TPAE, the reaction between the carbon filaments and TPAE is promoted, and the bond strength between the yarn 16 and the belt body 10 is dramatically improved. In this toothed belt 10 , the yarn 16 is prevented from peeling off from the belt body 11 . Since the movement of the filament 18 is suppressed, the reduction in strength of the core wire 13 due to wear of the carbon filament is prevented.

From the viewpoint that the belt body 11 and the yarn 16 are strongly bonded via the adhesive coating layer 21, the curing agent is more preferably an azo polymerization initiator among radical initiators. In this case, from the viewpoint that the adhesive coating layer 21 can effectively contribute to adhesion and restraint of the filament 18, the amount of the curing agent is 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the epoxy group-containing compound. is more preferable.

This toothed belt 10 uses an aqueous solution containing resorcin and formaldehyde and having a solid content ratio of 80% by mass or more, for example, instead of an emulsion containing an epoxy group-containing compound and a curing agent, as the above adhesive. be able to.
This aqueous solution is also called an RF liquid, and the solid content ratio of the main agent is represented by the solid content ratio of the initial condensate of resorcinol and formaldehyde.
Regarding the precondensate (RF) of resorcin (R) and formaldehyde (F) in the RF liquid, the molar ratio (R/F) of resorcin (R) to formaldehyde (F) is, for example, 1/3 to 1/0. 5.
Even if an RF liquid is used as the adhesive, the yarn 16 is firmly adhered to the belt body 10 through the adhesive coating layer 21, so the yarn 16 is prevented from peeling off from the belt body 10. Since the movement of the filament 18 is suppressed, the reduction in strength of the core wire due to wear of the carbon filament is prevented. Furthermore, in this case, the adhesive coating layer 21 is formed softer than when the solution containing the epoxy group-containing compound and the curing agent is used as the adhesive. Since the core wire 13 is easily bent, even if the toothed belt 10 is used for a pulley with a small pulley diameter that causes a large strain in the core wire 13, the core wire 13 is unlikely to be cut.

In this toothed belt 10, the RF liquid as an adhesive can contain chemicals such as latex within a range that does not impair the function.
Examples of the latex include vinylpyridine/styrene/butadiene rubber latex (VP/SBR), styrene/butadiene rubber latex (SBR), natural rubber latex (NR), chloroprene rubber latex (CR), and chlorosulfonated polyethylene rubber latex. (CSM), 2,3-dichlorobutadiene rubber latex (2,3-DCB), hydrogenated nitrile rubber latex (H-NBR), carboxylated hydrogenated nitrile rubber latex, butadiene rubber latex (BR), nitrile rubber latex ( NBR) and the like. The adhesive can contain one or more of these.

If the adhesive is an aqueous solution comprising a precondensate of resorcinol and formaldehyde and a latex as described above, this sizing agent is also referred to as an RFL aqueous solution. In this case, the total solid content ratio of the initial condensate content of resorcin and formaldehyde in the RFL aqueous solution and the latex-derived solid content is, for example, 10% by mass or more and 30% by mass or less.
Regarding the precondensate (RF) of resorcin (R) and formaldehyde (F) in the RFL aqueous solution, the molar ratio (R/F) of resorcin (R) to formaldehyde (F) is, for example, 1/3 to 1/0. 5. The mass ratio (RF/L) of the initial condensate (RF) of resorcin (R) and formaldehyde (F) in the RFL aqueous solution to the latex-derived solid content (L) is, for example, 1/10 to 1/0, preferably is around 1/6.

In this toothed belt 10, as shown in FIG. 4, each filament 18 contained in a strand 17 is coated with a converging coating layer 20 made of a sizing agent. A strand 17 is formed by twisting a large number of filaments 18 together. In this toothed belt 10 there is a converging coating layer 20 between the filaments 18 . The yarn 16 comprising this strand 17 comprises a number of filaments 18 and a converging coating layer 20 covering each filament 18 .

In this toothed belt 10, since the converging coating layer 20 exists between the filaments 18, the filaments 18 are prevented from directly rubbing against each other. The converging coating layer 20 and the adhesive coating layer 21 firmly bond the filaments 18 to the belt body 11 (specifically, the back rubber portion 11a). Even if the boundary portion between the yarn 16 and the belt body 10 is distorted when the belt is driven, the yarn 16 is prevented from peeling off from the belt body 10.例文帳に追加
In this toothed belt 10, since the converging coating layer 20 and the adhesive coating layer 21 effectively constrain the filaments 18, movement of the filaments 18 is suppressed. Since the friction of the carbon filaments is suppressed, the reduction in strength of the core wire 13 due to wear of the carbon filaments is prevented.
The toothed belt 10 maintains a state suitable for high-load transmission over a long period of time. From this point of view, in this toothed belt 10, each filament 18 contained in the yarn 16 is preferably coated with a converging coating layer 20 made of a sizing agent. If the yarn comprises two or more strands 17, each strand 17 comprising a number of twisted filaments 18, each filament 18 in the strand 17 is coated with a converging coating layer 20 of a sizing agent. is preferred.

In this toothed belt 10, as a sizing agent for the sizing coating material 20, for example, an emulsion in which an epoxy group-containing compound and a curing agent are dispersed in water can be used. In this case, from the viewpoint that the converging coating layer 20 in the toothed belt 10 can effectively contribute to maintaining a state suitable for high-load transmission, the converging agent contains an epoxy group-containing compound and a curing agent as main ingredients. An emulsion in which the solid content ratio of the main agent is 80% by mass or more is preferable.
Examples of epoxy group-containing compounds contained in this sizing agent include sorbitol polyglycidyl ether, glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolpropane polyglycidyl ether, and the like. Among these, polyglycerol polyglycidyl ether is preferred.
Examples of curing agents include isocyanate-based curing agents and amine-based curing agents. In the toothed belt 10, any one of these may be used alone, or two or more thereof may be used in combination.
Examples of isocyanate-based curing agents include naphthalene diisocyanate, isophorone diisocyanate, 4,4′-diphenylmethane diisocyanate, toluene-2,4-diisocyanate, xylylene diisocyanate, tolylene diisocyanate, polymethylene polyphenyl diisocyanate, hexamethylene diisocyanate, and the like. be done. Among these, 4,4'-diphenylmethane diisocyanate is preferred.
A commercial item can also be used as an isocyanate-type hardening|curing agent. Examples of commercially available isocyanate curing agents include "Grilbond IL-6" manufactured by EMS.
Examples of amine-based curing agents include imidazole-based compounds, diamine compounds, compounds having an oxazole ring, and the like. Among these, imidazole compounds are preferred.
Commercially available products can be used as the amine curing agent. Commercially available products of this amine-based curing agent include, for example, "Curesol" manufactured by Shikoku Kasei Co., Ltd.

The toothed belt 10 can also use the RF liquid described above as a sizing agent. In this case, the converging coating layer 20 is softer than the converging coating layer 20 obtained when an emulsion containing an epoxy group-containing compound and a curing agent is used as a sizing agent. Although the soft converging coating layer 20 constrains the movement of the filaments 18, the filaments 18 are allowed to move slightly. The toothed belt 10 facilitates adhesive treatment of the yarns 16 because the filaments 18 are flexible. In this toothed belt 10, the yarns 16 are firmly adhered to the belt body 11. - 特許庁Therefore, even if a high load acts on the toothed belt 10 , the yarn 16 is less likely to separate from the belt body 11 . The soft converging coating layer 20 effectively relieves the strain induced in the yarns 16 . Therefore, even if the toothed belt 10 is used for a pulley with a small pulley diameter, the cord 13 is unlikely to be cut.
The toothed belt 10 maintains a state suitable for high-load transmission over a long period of time. From this point of view, it is preferable to use an RF liquid as a sizing agent.

In this toothed belt 10, the sizing agent can contain a chemical such as latex as long as the sizing agent does not impair its function.
Examples of the latex include vinylpyridine/styrene/butadiene rubber latex (VP/SBR), styrene/butadiene rubber latex (SBR), natural rubber latex (NR), chloroprene rubber latex (CR), and chlorosulfonated polyethylene rubber latex. (CSM), 2,3-dichlorobutadiene rubber latex (2,3-DCB), hydrogenated nitrile rubber latex (H-NBR), carboxylated hydrogenated nitrile rubber latex, butadiene rubber latex (BR), nitrile rubber latex ( NBR) and the like. The sizing agent can contain one or more of these.

In the toothed belt 10, structurally, shear strain is likely to occur in the vicinity of the boundary between the back rubber portion 11a and the tooth rubber portion 11b. In particular, as described above, from the viewpoint of suppressing the occurrence of back cracks, the back rubber portion 11a is made of a soft thermoplastic elastomer composition, and the tooth rubber portion 11b is made of a hard thermoplastic elastomer composition compared to the back rubber portion 11a. When it is composed of an elastomer composition, the vicinity of this boundary is susceptible to shear strain due to the difference in rigidity.
The core wire 13 of the toothed belt 10 is arranged on the inner peripheral side of the back rubber portion 11a. In other words, the core wire 13 is located near the boundary between the back rubber portion 11a and the tooth rubber portion 11b. Therefore, the interface between the cord 13 and the back rubber portion 11a is susceptible to this shear strain. However, the yarns 16 contained in the cord 13 are covered with an adhesive coating layer 21 of the adhesive described above. The filaments 18 contained in this yarn 16 are preferably coated with a converging coating layer of the sizing agent described above. This core wire 13 can effectively mitigate the effect of shear strain described above. The toothed belt 10 maintains a state suitable for high-load transmission over a long period of time.

(Production method)
This manufacturing method will be described with reference to FIGS.
FIG. 5 is a partial cross-sectional view of a belt mold used in the method of manufacturing a toothed belt. 6 to 8 are diagrams for explaining the manufacturing steps of the manufacturing method.
The manufacturing method has a material preparation process, a lamination process, a molding process, and a finishing process.

<Material preparation process>
≪Elastomer sheet≫
A thermoplastic elastomer sheet for the back rubber portion and a thermoplastic elastomer sheet for the tooth rubber portion are prepared. Each elastomer sheet is obtained, for example, by preparing a thermoplastic elastomer composition containing TPAE or TPC as an elastomer component and necessary additives, and molding this into a sheet by extrusion molding or the like.
Further, the thermoplastic elastomer sheet for the back rubber portion and the thermoplastic elastomer sheet for the tooth rubber portion may be formed by co-extrusion. In this case, a laminate of the thermoplastic elastomer sheet for the back rubber portion and the thermoplastic elastomer sheet for the tooth rubber portion is obtained.
The elastomer sheet molded in this step may be temporarily wound up, or may be supplied as it is to the next step.

≪Reinforcing cloth≫
A reinforcing cloth (tooth covering material) having a tooth profile corresponding to the shape of the belt teeth 12 is prepared.
The reinforcing cloth is placed along the heated mold, which has recesses of the same shape as the teeth of the belt, and a soft elastic body is pressed from the opposite side of the mold to mold the reinforcing cloth into a toothed shape. .
The profiled reinforcing fabric may then be formed into a tubular shape. If desired, the reinforcement fabric can be subjected to a bonding treatment such as an RFL treatment.

≪Core wire≫
A core wire 13 is prepared by subjecting a carbon filament to a predetermined twist, bonding treatment, or the like. Here, it is preferable to prepare an S-twisted core wire and a Z-twisted core wire as a pair of core wires.
A bundle of filaments 18 is twisted to form a strand 17 . When each filament 18 is coated with the converging coating layer 20, the bundle of filaments 18 is immersed in a solution containing a sizing agent, the sizing agent is applied to the entire surface of each filament 18, and then the bundle is twisted to form a strand. 17. As a result, strands 17 impregnated with a sizing agent between filaments 18 are obtained. After that, the strand 17 is heated to volatilize the dispersion medium contained in the sizing agent and dry the sizing agent. This results in a strand 17 containing filaments 18 coated with a converging coating layer 20 (thickness=0.05-0.35 μm) of a sizing agent. The heating temperature in the sizing agent treatment is set to, for example, 180° C. or higher and 250° C. or lower. The heating time is set to, for example, 3 minutes or more and 10 minutes or less.

A yarn 16 is formed by twisting a plurality of strands 17 together. When the yarn 16 is coated with the adhesive coating layer 21, the yarn 16 is immersed in a solution containing the adhesive to apply the adhesive to the entire surface of the strands 17. FIG. As a result, a coating layer of adhesive is formed on the surface of the yarn 16 . Thereafter, the coating layer is heated to volatilize the dispersion medium contained in the coating layer, and the coating layer is dried. As a result, the core wire 13 is obtained in which the adhesive coating layer 21 (thickness=0.15 to 0.8 μm) made of adhesive is formed on the surface of the yarn 16 . The heating temperature in the adhesive treatment is set to, for example, 180° C. or higher and 250° C. or lower. The heating time is set to, for example, 3 minutes or more and 10 minutes or less.

When the filaments 18 included in the yarn 16 include polyamide filaments, the core wire 13 is subjected to heat treatment. By this heat treatment, the melted polyamide filaments enter between the carbon filaments, and the core wire 13 containing the melted polyamide filaments is obtained. This heat treatment may be performed during drying in the adhesive treatment. In this case, the heating temperature and time in this heat treatment are considered for the heating temperature and time during drying.

<Lamination process>
FIG. 5 is a partial cross-sectional view showing part of the belt molding die 30. As shown in FIG.
The belt forming die 30 is cylindrical and has an outer peripheral surface in which a plurality of axially extending tooth forming grooves 31 are arranged at intervals in the circumferential direction.

As shown in FIG. 6, the outer peripheral surface of the belt forming die 30 is covered with a toothed tubular reinforcing cloth 14, and a pair of core wires 13 are spirally wound thereon.
Then, the thermoplastic elastomer sheet 11b' for the tooth rubber portion and the thermoplastic elastomer sheet 11a' for the back rubber portion are wound thereon in this order. The number of layers of each wound sheet may be one or two or more depending on the dimensions of the belt to be produced.
Furthermore, a release paper or a release film (not shown) is wound as necessary.
Thereby, the laminate S′ is molded on the belt molding die 30 .

<Molding process>
A jacket having a rubber sleeve 32 on its inner surface and a closed space between the sleeve 32 and the main body is placed over the laminate S'. As a result, as shown in FIG. 7, the laminated body S' on the belt mold 30 is covered with the rubber sleeve 32. Next, as shown in FIG.
High-pressure steam is introduced into the interior of the mold 30 around which the laminate S' is wound and the space between the jacket to heat and compress. As a result, the thermoplastic elastomer forming the thermoplastic elastomer sheets 11a' and 11b' is passed through the gaps between the cords and poured into the tooth forming grooves 31, thereby forming the belt teeth 12 as shown in FIG. .
At this time, the temperature of the high-pressure steam is set to a temperature equal to or higher than the temperature at which the thermoplastic elastomer flows. In addition, when the elastomer component of the thermoplastic elastomer sheet is TPAE, the temperature of the high-pressure steam is set to 170° C. or higher.

After the belt teeth 12 are formed, the jacket and mold 30 are cooled with water or the like to lower the temperature of the elastomer to 100° C. or less, and then the mold 30 and molded body S are removed from the jacket. Furthermore, when the temperature of the molded body S is 40° C. or higher, the molded body S is further cooled, and when the temperature of the molded body S drops below 40° C., the molded body S is removed from the mold 30 .

<Finishing process>
The toothed belt 10 is obtained by cutting the molded article S taken out into a specified width and separating it.
Through such steps, the toothed belt 10 in which the belt body 11 is made of the thermoplastic elastomer composition can be manufactured.

<Others>
If the thermoplastic elastomer sheet 11b' for the tooth rubber and the thermoplastic elastomer sheet 11a' for the back rubber are different in hardness, the reinforcing cloth 14 and the core wire are placed on the outer peripheral surface of the belt molding die 30. 13 and the thermoplastic elastomer sheet 11b' for the tooth rubber are laminated, then heated and compressed by the above-described high-pressure steam to form the belt teeth, cooled once, and then the thermoplastic elastomer sheet for the back rubber. 11a' is wound thereon, heated and compressed again by high-pressure steam, then cooled again, and finally finished, to produce a toothed belt.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples.

Here, a toothed belt with a tooth type of S8M was produced and its performance was evaluated.
The toothed belt of each example was manufactured using the manufacturing method already explained above.
A thermoplastic elastomer composition, cords, and reinforcing cloth for forming the belt body (back rubber portion and tooth rubber portion) were prepared as follows.

(Thermoplastic elastomer composition)
The following thermoplastic elastomer composition (TPE) was prepared. Both thermoplastic elastomer compositions are commercially available.

TPAE: polyamide-based thermoplastic elastomer composition (A1) PEBAX (registered trademark) 4033SP-01 manufactured by Arkema was used. The hardness of this thermoplastic elastomer composition is 42.
PEBAX uses polyether as the soft segment.
(A2) TPAE-10 manufactured by T&K TOKA was used. The hardness of this thermoplastic elastomer composition is 41.
TPAE-10 has polyetherester as the soft segment.
(A3) PEBAX (registered trademark) 2533SP-01 manufactured by Arkema was used. The hardness of this thermoplastic elastomer composition is 27.

TPO: Polyolefin Thermoplastic Elastomer Composition EXCELINK (registered trademark) 1303B manufactured by JSR Corporation was used. The hardness of this thermoplastic elastomer composition is 38. This hardness is measured in a Type A durometer, not a Type D durometer.

TPU: Polyurethane Thermoplastic Elastomer Composition Miractran (registered trademark) E590 manufactured by Miractran Japan Co., Ltd. was used. The hardness of this thermoplastic elastomer composition is 42.

(reinforcement cloth)
An RFL-treated nylon canvas was prepared as a reinforcing cloth.
In this case, a woolly textured nylon canvas with 6,6-nylon fibers for the warp and 6,6-nylon fibers for the weft was prepared.

(Core wire)
Using carbon filaments (manufactured by Teijin Tenax Co., Ltd., filament diameter 7 μm), core wires containing plied type yarns having the configuration (1×5) shown in FIG. 4 were prepared. The number of carbon filaments contained in the strand was set at 3000.

(Sizing agent and adhesive)
The following processing solutions A to G were prepared for forming the converging coating layer and the adhesive coating layer.
・Treatment liquid A
Using “Denacol EX-521” manufactured by Nagase Chemtech Co., Ltd., a treatment liquid A containing an epoxy group-containing compound as a main agent was prepared. The solid content ratio of the main agent in this treatment liquid A was 100% by mass.
・Processing liquid B
Using "Denacol EX-521" manufactured by Nagase Chemtech Co., Ltd. and "Curesol 2E4MZ-CN" manufactured by Shikoku Kasei Co., Ltd., a treatment liquid B containing an epoxy group-containing compound and an amine-based curing agent as the main agent was prepared. In this treatment liquid B, the solid content ratio of the main agent was 100% by mass. The amount of the amine curing agent was 9.5 parts by mass with respect to 100 parts by mass of the epoxy group-containing compound.
・Processing liquid C
"Denacol EX-521" manufactured by Nagase Chemtech Co., Ltd., "Cure Sol 2E4MZ-CN" manufactured by Shikoku Kasei Co., Ltd., and "VP Latex 0650" manufactured by JSR Co., Ltd. are used as the main agent, and an epoxy group-containing compound as the main agent. and an amine-based curing agent and a latex as an impurity was prepared. The solid content ratio of the main agent in this treatment liquid C was 70% by mass. The amount of the amine curing agent was 9.5 parts by mass with respect to 100 parts by mass of the epoxy group-containing compound.
・Treatment liquid D
Using "Denacol EX-521" manufactured by Nagase Chemtech Co., Ltd. and "Water-soluble azo polymerization initiator VA-086" manufactured by Wako Pure Chemical Industries, Ltd., as the main agent, a treatment liquid containing an epoxy group-containing compound and a radical initiator. Prepare D. The solid content ratio of the main agent in this treatment liquid D was 100% by mass. The amount of the radical initiator was 5 parts by mass with respect to 100 parts by mass of the epoxy group-containing compound.
・Processing liquid E
Using "Denacol EX-521" manufactured by Nagase Chemtech, "Water-soluble azo polymerization initiator VA-086" manufactured by Wako Pure Chemical Industries, Ltd., and "VP Latex 0650" manufactured by JSR, epoxy as the main agent A treatment liquid E containing a group-containing compound, a radical initiator, and latex as an impurity was prepared. In this treatment liquid E, the solid content ratio of the main agent was 70% by mass. The amount of the radical initiator was 5 parts by mass with respect to 100 parts by mass of the epoxy group-containing compound.
・Processing liquid F
As the treatment liquid F, an RF liquid was prepared. The solid content ratio of the precondensate of resorcinol and formaldehyde was 100% by mass. The molar ratio (R/F) of resorcin (R) to formalin (F) was 1/1.5.
・Processing liquid G
As the treatment liquid G, an RFL aqueous solution (latex is "VP Latex 0650" manufactured by JSR Corporation) was prepared. In this RFL aqueous solution, the solid content ratio of the initial condensate of resorcinol and formaldehyde was 70% by mass. The molar ratio (R/F) of resorcin (R) to formalin (F) is set to 1/1.5, and the initial condensate (RF) of resorcin (R) and formaldehyde (F) to latex-derived solids (L) The mass ratio (RF/L) was set to 1/6.

[Example 1]
Using the above TPAE (A1) for the back rubber portion and the tooth rubber portion, using the above nylon canvas as the reinforcing cloth, and using the above core wire containing the carbon filament, the above-described manufacturing method (see FIGS. 6 to 9) ) produced a toothed belt with a tooth type of S8M. The belt width was 8 mm and the belt length was 1200 mm.
For the cord, a yarn of the type shown in FIG. 4 was prepared, specifically a plied type yarn having two layers of twist consisting of a ply and a ply.
The number of filaments included in each strand included in the yarn was set to 3000. All of the filaments were composed of carbon filaments.
After a bundle of filaments was immersed in a treatment liquid F as a sizing agent, the bundle of filaments was pre-twisted to form a strand. This strand was heat-treated at a temperature of 180° C. for 5 minutes. This formed a converging coating layer filling between the filaments of the strand. The twist factor for the first twist was set to 40.
Five strands on which the converging coating layer was formed were prepared and ply-twisted to constitute a yarn. The twist factor for the ply twist was set to 40.
Using treatment liquid F as an adhesive, the yarn was treated with an adhesive to form an adhesive coating layer on the surface of the yarn. The heating temperature in this treatment was set at 220° C., and the heating time was set at 10 minutes.

[Comparative Example 1]
A toothed belt of Comparative Example 1 was obtained in the same manner as in Example 1, except that the converging coating layer and the adhesive coating layer were not formed.

[Comparative Examples 2-3]
The procedure of Example 1 was repeated except that the thermoplastic elastomer composition for the back rubber portion and tooth rubber portion was as shown in Table 1 below, treatment liquid A was used as the sizing agent, and treatment liquid D was used as the adhesive. Thus, a toothed belt of Comparative Example 1 was obtained.

[Example 2]
A toothed belt of Example 2 was obtained in the same manner as in Example 1, except that treatment liquid D was used as the adhesive.

[Example 3]
In the same manner as in Example 1, except that the above TPAE (A2) was used as the thermoplastic elastomer composition for the back rubber portion and the tooth rubber portion, the treatment liquid B was used as the sizing agent, and the treatment liquid D was used as the adhesive. A toothed belt of Example 3 was obtained.

[Examples 4-6]
Toothed belts of Examples 4 to 6 were obtained in the same manner as in Example 1 except that the sizing agent and adhesive were as shown in Table 2 below.

[Example 7]
A toothed belt of Example 7 was obtained in the same manner as in Example 1 except that the above TPAE (A3) was used for the back rubber portion and the above TPAE (A1) was used for the tooth rubber portion.

(Evaluation method)
Durability Tests 1 and 2 were performed to evaluate the durability of the toothed belts produced in Examples and Comparative Examples. The results are shown in Table 1.

<Durability test 1>
Durability test 1 is a test for evaluating durability under standard running conditions. The toothed belts produced in Examples 1-7 and Comparative Examples 1-3 were tested.
FIG. 9 shows the belt running tester 80 used in the durability test 1. As shown in FIG.
The belt running tester 80 includes a drive pulley 81 with 22 teeth and an 8M tooth profile, and a driven pulley 82 with 33 teeth and an 8M tooth profile provided on the right side of the driving pulley 81 . The driven pulley 82 is provided movably to the left and right so as to be able to apply an axial load (dead weight).

The toothed belt 110 manufactured in each of Examples 1 to 7 and Comparative Examples 1 to 3 is wound between the drive pulley 81 and the driven pulley 82 of the belt running tester 80, and is stretched to the right side of the driven pulley 82. A shaft load of 608 N is applied to apply belt tension, a rotational load of 34.2 N·m is applied to the driven pulley 82, and the driving pulley 81 is rotated at a rotational speed of 4200 times per minute at room temperature to run the belt. let me The running of the belt is periodically stopped to visually check for cracks on the back side of the back rubber, wire breakage, wire sticking out, etc., and the belt running time until failure is confirmed. was measured. The maximum belt running time was set to 1000 hours.
Moreover, when tooth jumping occurred even though failure did not occur, the test was terminated at that point.

<Durability test 2>
Durability test 2 is a test for evaluating durability under high load conditions. The toothed belts manufactured in Examples 1 and 3 and Comparative Examples 1 to 3 were tested.
FIG. 10 shows the belt running tester 90 used in the second durability test.
The belt running tester 90 includes a driving pulley 91 having 24 teeth and an 8M tooth profile, and a driven pulley 92 having 36 teeth and an 8M tooth profile provided on the right side of the driving pulley 91 . The driven pulley 92 is provided movably to the left and right so as to be able to apply an axial load (dead weight).

The toothed belt 120 manufactured in each of Examples 1 and 3 and Comparative Examples 1 to 3 is wound between the drive pulley 91 and the driven pulley 92 of the belt running tester 90, and the right side of the driven pulley 92 A shaft load of 520 N was applied to the other side to give belt tension, a rotational load of 39.2 N·m was applied to the driven pulley 92, and the driving pulley 91 was rotated at a speed of 3000 times per minute at room temperature. I let the belt run. Then, the running of the belt was periodically stopped to visually check for failures such as tooth chipping, wire breakage, and wire sticking out, and the belt running time until failure was confirmed was measured.
When tooth jumping occurred even though cracks did not occur, the test was terminated at that point.

As shown in Table 1-2, the toothed belt according to the embodiment of the present invention maintains a state suitable for high load transmission over a long period of time. This toothed belt has excellent bending fatigue resistance and is suitable for high-load transmission.

INDUSTRIAL APPLICABILITY The present invention is useful in the technical field of toothed belts in which a plastic elastomer composition is used as a material for the tooth rubber portion and the back rubber portion.

REFERENCE SIGNS LIST 10, 110, 120 toothed belt 11 belt body 11a back rubber portion 11b tooth rubber portion 12 belt teeth 13 cord 14 reinforcing cloth (tooth covering material)
15 Tooth Bottom 16 Yarn 17 Strand 18 Filament 19 Temporary Strand 20 Converging Coating Layer 21 Adhesive Coating Layer 30 Belt Mold 31 Tooth Forming Groove 32 Rubber Sleeve 80, 90 Belt Tester 81, 91 Drive Pulley 82, 92 Driven Pulley

Claims (6)

a flat belt-shaped back rubber portion; and a plurality of tooth rubber portions disposed on the inner peripheral side of the back rubber portion and integrally provided with the back rubber portion to constitute belt teeth, a belt body in which both the rubber portion and the tooth rubber portion are made of a thermoplastic elastomer composition;
a core wire arranged and embedded so as to form a spiral having a pitch in the width direction of the belt in the portion on the inner peripheral side of the back rubber portion;
a tooth portion covering material covering the plurality of tooth rubber portions provided on the inner peripheral side of the belt body;
with
The elastomer component of the thermoplastic elastomer composition is a thermoplastic polyamide elastomer (TPAE) or a thermoplastic polyester elastomer (TPC),
The thermoplastic elastomer composition constituting the back rubber portion has a hardness of 25 to 70,
The thermoplastic elastomer composition constituting the tooth rubber portion has a hardness of 40 to 70, and the thermoplastic elastomer composition constituting the back rubber portion has a hardness equal to or higher than that of the thermoplastic elastomer composition,
the cord comprises yarns coated with an adhesive coating layer of adhesive;
The toothed belt, wherein the yarn includes a large number of filaments, and the large number of filaments includes carbon filaments made of carbon fibers. The toothed belt according to claim 1, wherein the elastomer component of said thermoplastic elastomer composition is thermoplastic polyamide elastomer (TPAE). The toothed belt according to claim 1 or 2, wherein the adhesive contains an epoxy group-containing compound and a curing agent, and has a solid content ratio of 80% by mass or more. The toothed belt according to claim 3, wherein said curing agent is a radical initiator. The toothed belt according to claim 1 or 2, wherein the adhesive contains resorcin and formaldehyde and has a solid content ratio of 80% by mass or more. The toothed belt according to any one of claims 1 to 5, wherein the soft segment of said thermoplastic polyamide elastomer (TPAE) has a polyether structure.

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