JP3212928B2 - Transmission belt - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission belt such as a V-belt or a V-ribbed belt, and more particularly to a technical field for reducing the cost of the power transmission belt.

[0002]

2. Description of the Related Art Conventionally, transmission belts such as V-belts and V-ribbed belts are well known. As a V-belt, a wrapped type in which the entire outer periphery is covered with a covering cloth, or no V-belt having only a side canvas. There is a low edge type where rubber is exposed. In the manufacturing process of this low-edge type V-belt, the belt material is mounted on a vulcanizing can and vulcanized to a cylindrical shape corresponding to the belt length, and then the formed material is adjusted to the belt width. After being cut in an annular shape, each of them is ground so that the cross section becomes trapezoidal.

The V-ribbed belt has a plurality of V-ribs extending in the belt longitudinal direction with respect to a belt base. In the manufacturing process, like the low-edge type V-belt, the V-ribbed belt is annular after vulcanization. The V-rib shape is cut out by grinding the bottom rubber portion.

[0004]

In the above-mentioned conventional low-edge V-belts and V-ribbed belts, rubber scraps are generated by grinding during the manufacturing process and are discarded. Reach nearby.

In addition, defective products generated in the manufacturing process, including not only the low-edge type V-belt and V-ribbed belt but also wrapped-type V-belts and transmission belts, are discarded. Therefore, in the process of manufacturing the power transmission belt, a large amount of waste material such as vulcanized rubber and fiber is generated in combination with the rubber scrap generated by grinding as described above. There is a problem of pushing up.

[0006] The present invention has been made in view of such a point, and an object of the present invention is to add waste such as rubber scraps and used belts generated during the production of V-belts and V-ribbed belts. Paying attention to the fact that vulcanized rubber and fibers are included, vulcanized rubber containing them is used as a part of the material of the transmission belt under predetermined conditions, while considering environmental conservation, The purpose is to reduce the cost of the transmission belt.

[0007]

In order to achieve the above-mentioned object, according to the present invention, powder rubber is mixed with unvulcanized new rubber and used in the process of producing a power transmission belt. .

More specifically, according to the first aspect of the present invention, an adhesive rubber layer in which a cord extending in the belt length direction is embedded,
It is assumed that a transmission belt includes a tension rubber layer and a compression rubber layer provided on the outer surface of the adhesive rubber layer and the inner surface of the belt, respectively. And the above adhesive rubber layer,
At least one of a tension rubber layer or a compression rubber layer,
In the unvulcanized state of the belt manufacturing process, it is composed of a rubber composition in which powder rubber formed from rubber waste of the belt is mixed, and as a mixing ratio of the powder rubber, the mixing target layer is When composed of any of natural rubber, styrene butadiene rubber, butadiene rubber, highly saturated nitrile rubber, chlorosulfonated polyethylene rubber or alkylated chlorosulfonated polyethylene rubber,
The weight ratio is 30% or less, and when the layer to be mixed is made of chloroprene rubber, the weight ratio is 25% or less.

According to this structure, at least one of the adhesive rubber layer, the tension rubber layer and the compression rubber layer of the transmission belt is provided.
On the other hand, since powder rubber is mixed in as a filler, the amount of new rubber can be reduced by that amount, and material costs can be reduced.

[0010] In addition, the above-mentioned powdered rubber can be recycled by using rubber waste generated by grinding in the belt manufacturing process or crushed rubber waste such as defective products and used rubber belts. The cost required for disposal can be reduced, and belt manufacturing costs can be reduced. In addition, by effective use of resources and reduction of waste,
It is also useful for environmental protection.

Further, by limiting the mixing ratio of the powder rubber to the above-mentioned predetermined ratio or less, it is possible to suppress the deterioration of the adhesiveness of the rubber sheet before vulcanization due to excessive mixing of the powder rubber. Easiness of the operation at the time can be secured. In addition, a decrease in the fluidity of the rubber during vulcanization molding can be suppressed, and further, surface roughness after vulcanization, deterioration in flexibility and the like can be suppressed.

According to the second aspect of the present invention, there is provided an adhesive rubber layer in which a cord extending in the belt length direction is buried, and an overcord layer and an under code layer provided on the outer and inner belt sides of the adhesive rubber layer, respectively. It is assumed that the transmission belt includes a cord layer and a bottom rubber layer provided on the inner side of the belt of the under cord layer. Then, at least one of the adhesive rubber layer, the overcord layer, the undercord layer and the bottom rubber layer is mixed with powder rubber formed from rubber waste of the belt in an unvulcanized state in a manufacturing process. The mixture of the powder rubber is composed of a natural rubber, a styrene butadiene rubber, a butadiene rubber, a highly saturated nitrile rubber,
When it is composed of either chlorosulfonated polyethylene rubber or alkylated chlorosulfonated polyethylene rubber, the weight ratio is 30% or less, and when the layer to be mixed is composed of chloroprene rubber. Is configured to have a weight ratio of 25% or less.

According to this structure, material costs and belt manufacturing costs can be reduced as in the first aspect of the invention, and it is also useful for environmental protection. In addition, as in the case of the first aspect of the present invention, the easiness of the operation in the manufacturing process can be ensured, and furthermore, the roughening of the surface of the rubber after vulcanization and the deterioration of the flexibility can be suppressed .

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a wrapped V-belt WB as a transmission belt according to a first embodiment of the present invention. The V-belt WB has a well-known basic structure. The V-belt WB has an adhesive rubber layer 2 in which cable cords (core wires) 1, 1, ... extending in the belt length direction are embedded, and an upper surface side (belt) of the adhesive rubber layer 2. Outer side)
And an undercord layer 3 and an undercord layer 4 provided on the bottom surface side (the inner surface side of the belt), respectively, and a bottom rubber layer 5 provided on the bottom surface side of the undercord layer 4,
The outer periphery is covered with the outer covering 6 over the entire belt length direction.

As a feature of the present invention, the above-mentioned overcord layer 3, undercord layer 4, and bottom rubber layer 5
It is composed of a rubber composition in which a powder rubber material for recycling is mixed in an unvulcanized state in a manufacturing process, and the short fibers 10, 10,... Contained in the recycled material are oriented substantially in the belt width direction. ing.

The powder rubber is, for example, scrap rubber obtained by grinding a low-edge type V belt or V-ribbed belt, or
After various used power transmission belts are cut into pieces in advance, those that have been roughly pulverized are further finely pulverized by a pulverizer. At this time, the particle diameter of the powder rubber is 1.6 mm or less, and the short fibers 10, 10,.
Is finely pulverized so that the average length is 4 mm or less.
By this, the rubber sheet kneaded with the powder rubber,
Roughness of the sheet surface such as pin holes and projections is suppressed.

The powder rubber thus recycled includes chloroprene rubber, natural rubber, styrene butadiene rubber, butadiene rubber, highly saturated nitrile rubber, chlorosulfonated polyethylene rubber (hereinafter referred to as CSM), alkylated chlorosulfonated rubber. Polyethylene rubber (hereinafter A
CSM) and short fibers 1
0, 10,... Are common components of the belt,
It contains cotton, tetron, nylon, vinylon or aramid.

In the manufacturing process of the V belt WB,
The powder rubber is mixed with the new rubber, kneaded with a kneader, a Banbury mixer or the like, and uniformly dispersed. At this time, the mixing ratio of the powder rubber is set to a maximum of 25 to 30% by weight depending on the type of the new rubber to be mixed. Thus, it is possible to prevent the dispersibility from being deteriorated due to excessive mixing of the powder rubber.

The kneaded rubber is rolled by a calender to form a rubber sheet in which the short fibers 10, 10,... Contained in the powder rubber are oriented at an orientation ratio of about 95% in the rolling direction. can get. This rubber sheet is
Since the mixing ratio of the powder rubber is limited to a predetermined value or less as described above, the surface roughness and the deterioration of the adhesiveness are suppressed, and the rubber sheet can be handled in the same manner as a rubber sheet in which the powder rubber is not mixed. Therefore, easiness of work in the manufacturing process is ensured.

Subsequently, the rubber sheet is cut in a direction perpendicular to its longitudinal direction (rolling direction), and the cut pieces are joined in the width direction of the rubber sheet (direction perpendicular to the rolling direction) to form short fibers. To obtain a rubber sheet oriented in the width direction. Using this rubber sheet, a V-belt WB in which short fibers 10, 10,... Are oriented in the belt width direction is manufactured by a known method. At this time, since the mixing ratio of the powder rubber in the rubber sheet is limited to a predetermined value or less as described above, it is possible to suppress a decrease in the fluidity of the new rubber at the time of vulcanization molding, and furthermore, the bending after vulcanization. The deterioration of the property can be suppressed.

Therefore, in this embodiment, powder rubber, which is a recycled material of the belt, is used as a filler for the rubber composition constituting the overcode layer 3, undercode layer 4, and bottom rubber layer 5 of the V belt WB. Because it was mixed,
The material cost can be reduced by reducing the amount of new rubber by that much. In addition, since the cost of disposing of the recycled material can be saved, the cost can be reduced, and the effective use of resources and the amount of waste can be reduced, which is useful for environmental protection.

Further, the short fibers 1 contained in the powder rubber
Are oriented substantially in the belt width direction in the overcode layer 3 and the undercode layer 4, the elastic modulus in the belt width direction can be selectively increased on both the upper and lower sides of the belt. This makes it possible to increase the lateral pressure resistance while ensuring the flexibility of the V-belt WB in the belt length direction. Here, if the powder rubber is a thermosetting chloroprene rubber composition, higher reinforcement can be expected. (Embodiment 2) FIG. 2 shows a low-edge type V-belt RE1,
Embodiment 2 applied to RE2 is shown (note that the same parts as those in FIG. 1 are denoted by the same reference numerals and detailed description thereof is omitted). The V belts RE1 and RE2 correspond to the V belts of the first embodiment.
Like the belt WB, the basic structure is well known. The V-belt RE1 shown in FIG. 1A has an upper rubber layer (tensile rubber layer) 7 provided on the upper surface side (belt outer surface side) of the adhesive rubber layer 2. An upper canvas 8 is integrally adhered to the upper surface of the upper rubber layer 7, while a bottom rubber layer (compressed rubber layer) 5 is provided on the bottom surface (bell and inner surface) of the adhesive rubber layer 2. And
The side surfaces of the upper rubber layer 7, the adhesive rubber layer 2, and the bottom rubber layer 5 are exposed.

A V-belt RE2 shown in FIG.
Has substantially the same configuration as the above-mentioned V-belt RE1, and further, the lower canvas 9, 9, 9 is laminated three times on the bottom surface side of the bottom rubber layer 5 to improve durability and quietness. Things.

In each of the V belts RE 1 and RE 2, the bottom rubber layer 5 has the same structure as in the first embodiment.
It is made of a rubber composition mixed with powder rubber recycled in an unvulcanized state in the manufacturing process, and the short fibers 10, 10,... Contained in the powder rubber are oriented substantially in the belt width direction. ing.

Therefore, in this embodiment, the same operation and effects as those of the first embodiment can be obtained, the cost can be reduced, and the invention is also useful for environmental protection. Further, on the side surface of the bottom rubber layer 5 which is in direct contact with the pulley, the portion of the fresh rubber absorbs elongation and compression, while the portion of the powder rubber bears friction with the pulley. The wear resistance of the layer 5 can be improved. (Other Embodiments) Note that the present invention is not limited to the above-described embodiment, but includes other various embodiments. That is, in the first and second embodiments, the fiber content contained in the crushed waste rubber is not removed, but is directly mixed into the new rubber. However, the present invention is not limited to this, and only the rubber component obtained by separating the fiber content is used. It may be mixed, or only the separated fibers may be mixed according to the specifications of the belt.

In the first and second embodiments, the present invention is applied to the wrapped V-belt WB and the low-edge V-belts RE1 and RE2, respectively, as the power transmission belt. The present invention can be applied to various transmission belts such as a belt, a V-ribbed belt, and a flat belt.

[0028]

Next, the wrapped V of the first embodiment will be described.
A specific example of the belt WB will be described.

First, as a recycled material to be mixed with the new rubber, grinding waste of a low-edge type V belt (see FIG. 2) is prepared, cut into 15 to 20 cm in advance with a guillotine cutter, and coarsely ground with a cracker roll. 2-5cm
Scrap rubber. This waste rubber is mainly composed of a chloroprene rubber composition. The waste rubber is divided into two stages by a pulverizer, that is, the first stage is pulverized with a 5.0 mmφ screen hole diameter, and the second stage is similarly pulverized with a 1.0 mmφ to reduce powder rubber. Obtained.

When this powder rubber is sent by a blower and separated by a cyclone, it can be easily separated into a fiber component and a rubber-based component, and the amount that can be recovered as a fiber component is about 20 to 25% of the whole. become. This fiber component is made of cotton, tetron, nylon, aramid, or the like, which is a belt constituent member. In particular, the material of the cable cord does not become filamentous, and a relatively long ply twist remains. Also,
The rubber-based material includes not only vulcanized rubber but also fiber.

Here, the relationship between the screen hole diameter of the pulverizer, the particle diameter of the powder rubber and the length of the fiber is as shown in the graph of FIG.
It can be seen that if crushed by φ, the particle size of the powder rubber can be reduced to 1.5 mm or less, and the length of the fiber can be reduced to 3 mm or less.

In order to examine the physical properties of the rubber sheet into which the powder rubber was mixed, powder rubber (which does not separate rubber and fiber), separated rubber from which fiber was removed, and separated fiber were Mixing and kneading natural rubber or new rubber of styrene-butadiene rubber while changing the mixing ratio to produce an unvulcanized rubber sheet, and then vulcanizing the rubber sheet to produce a vulcanized rubber sheet did.

The results of examining the physical properties of the unvulcanized rubber sheet and the vulcanized rubber sheet are as shown in Table 1.

[0034]

[Table 1]

In particular, FIG. 4 shows the correlation between the mixing ratio of the powder rubber in the unvulcanized rubber sheet and the deterioration of the adhesiveness.
Is shown by a solid line.

That is, in the unvulcanized rubber sheet, when the mixing ratio of the powder rubber is up to 20% by weight, the roll adhesiveness and the adhesiveness between the sheets are maintained well, and the belt is manufactured. The ease of operation in the process is ensured, but if the mixing ratio exceeds 25%, the adhesiveness gradually decreases, and if the mixing ratio becomes 40%, the operation becomes difficult due to insufficient adhesiveness. Therefore, based on FIG. 4, from the viewpoint of ensuring workability in the manufacturing process, it is considered that the mixing ratio of the powder rubber needs to be 30% or less by weight. In the unvulcanized rubber sheet,
Although the dispersibility of the rubber is kept good, the surface of the sheet is roughened and pin holes are generated.

In the rubber sheet after vulcanization,
When the mixing ratio is up to 20% by weight, there is no problem in any of orientation, anti-strike flexibility, hardness influence and adhesiveness, but when the mix ratio is 40%, the anti-strike flexibility deteriorates. I do. Here, the anti-strength bendability is the bendability in the anti-strike direction of the short fibers, that is, the direction orthogonal to the orientation direction (grain direction) of the short fibers, and the short fibers are oriented in the belt width direction. In this case, it is directly reflected on the bending durability of the transmission belt.

From the above, it is considered that the mixing ratio of the powder rubber to the natural rubber or the styrene-butadiene rubber composition is preferably up to 30% by weight.

In the case where the separated rubber is mixed and kneaded in place of the powder rubber, the adhesiveness of the unvulcanized rubber sheet is greatly reduced, and the orientation of the vulcanized rubber sheet is reduced. At the same time, the effects of anti-strength bendability and hardness are slightly deteriorated. Furthermore, in the case where the separated fiber component is mixed and kneaded in place of the powder rubber, the adhesive properties between the unvulcanized rubber sheets are slightly reduced, but as a whole, the same physical properties as when the powder rubber is mixed Is obtained.

On the basis of the above results, a kneaded rubber obtained by mixing and kneading powder rubber with natural rubber or a new rubber of styrene-butadiene rubber at a mixing ratio of 20% by weight was used.
A wrapped V-belt (see FIG. 1) was prototyped. At that time, the orientation direction of the short fibers in the powder rubber in the overcord layer was changed by 90 degrees, and the prototype specification 1 and the trial specification 2 were changed.
And For comparison, bench evaluation was performed by a standard bending durability test and a reverse durability test together with a current device not using powder rubber. Table 2 shows the specifications of the prototype belt and the current belt, and Table 3 shows the test results.
Are shown below.

[0041]

[Table 2]

That is, as shown in Table 2, the prototype specification 1
In both cases, the overcord layer and the undercord layer are formed by laminating a 0.8 mm thick rubber sheet in which powder rubber is mixed and kneaded at 20%. At that time, in the prototype specification 2, while the over-cord layer and the under-cord layer are anti-grained, the orientation direction of the short fibers is set in the belt width direction. The orientation direction is in the longitudinal direction of the belt (grain). Note that the current specification does not include an overcode layer and an undercode layer.

[0043]

[Table 3]

As shown in Table 3, the results of the bending durability test using each of the above test pieces show that the durability of both the prototype specifications 1 and 2 is greatly improved as compared with the current specifications.
This is particularly noticeable in prototype specification 2. This is undercode layer 4
It is considered that the short fibers included in the powder rubber in the bottom rubber layer 5 are oriented in the belt width direction, so that the lateral pressure resistance is improved while ensuring the flexibility of the belt in the longitudinal direction. .

The result of the reverse durability test is the current level in the prototype specification 1, but is significantly improved in the prototype specification 2.

Here, in the standard bending durability test, as shown in FIG. 5, a V-belt WB is wound around a driving pulley P1 and a driven pulley P2 having the same diameter, and a predetermined dead weight is set in a direction indicated by an arrow in the figure. While rotating at a predetermined constant rotation speed in an atmosphere at room temperature. In the reverse durability test, as shown in FIG. 6, a predetermined load is applied to the V belt WB wound between the driving pulley P1 and the driven pulley P2 having the same diameter from the outer peripheral side of the belt by the idler pulley P3. The bend was made to rotate at a predetermined constant rotational speed in an atmosphere at room temperature.

Next, the low-edge type V of the second embodiment
An embodiment of the belts RE1 and RE2 will be described.

First, for the new chloroprene rubber,
An unvulcanized rubber sheet and a vulcanized rubber obtained by vulcanizing the rubber sheet by mixing and kneading the powder rubber recycled without separating the rubber component and the fiber component as described above while changing the mixing ratio. A sheet was made. Table 4 shows the results of examining the physical properties of these unvulcanized and vulcanized rubber sheets.

[0049]

[Table 4]

FIG. 4 shows the correlation between the mixing ratio of the powder rubber in the unvulcanized rubber sheet and the deterioration of the adhesiveness.
Is indicated by a dashed line.

That is, in the unvulcanized rubber sheet, when the mixing ratio of the powder rubber is up to 15% by weight, the roll adhesiveness and the adhesiveness between the sheets are not impaired, and the work in the belt manufacturing process is not affected. However, when the mixing ratio becomes 20%, the tackiness gradually starts to be insufficient, and when the mixing ratio becomes 30%, the work becomes difficult due to the insufficient tackiness. Therefore, based on FIG. 4, from the viewpoint of ensuring workability in the manufacturing process, it is considered that the mixing ratio of the powder rubber needs to be 25% or less by weight. In addition, even in the unvulcanized rubber sheet, the dispersibility of the rubber is kept good, but the surface of the sheet starts to be rough when the mixing ratio is 20% or more.

Then, in the vulcanized rubber sheet,
When the mixing ratio is up to 20% by weight, there is almost no problem in any of the orientation, the anti-sequence bending property and the adhesiveness. However, when the mixing ratio exceeds 20%, the variation in rubber hardness becomes large, When the mixing ratio is 30%, the anti-strength bending property is degraded, and the variation in rubber hardness is greatly increased.

From the above, it is considered that the mixing ratio of the powder rubber to the chloroprene rubber composition is preferably up to 25% by weight.

Based on the above results, two types of unvulcanized rubber sheets were produced by mixing and kneading the powder rubber with the new chloroprene rubber at a mixing ratio of 15% and 20% by weight, respectively. . Then, using these two types of rubber sheets, two specifications (REs) shown in FIGS.
1, RE2) V-belts were prototyped in two ways each.
In addition, a high-temperature and high-speed durability test and a bending durability test were performed using a current material in which powder rubber was not mixed for comparison. Here, as shown in FIG. 7, in the high-temperature high-speed endurance test, a predetermined load is applied to the V-belt RE wound between the driving pulley P1 and the driven pulley P2 having the same diameter from the inner peripheral side of the belt by the idler pulley P3. In addition, high-speed rotation was performed in a high-temperature atmosphere. In addition, the bending durability test
As shown in FIG. 8, a V-belt RE was wound around an upper driving pulley P1 and a lower driven pulley P2, and the test was performed in an atmosphere at room temperature while applying a downward dead weight to the driven pulley P2. Table 5 shows the results of these tests.

[0055]

[Table 5]

That is, first, in the specification (a),
The results of the high-temperature high-speed endurance test show that 20%
%, Showed almost the same durability as the current one. On the other hand, the results of the bending durability test are almost the same as those of the current one when mixed at 15%, but the durability is remarkably improved when mixed at 20%.

In the specification (b), in both the high-temperature high-speed endurance test and the bending endurance test, a mixture of 15% shows almost the same durability as the current one, while 20%
When mixed, the durability is slightly reduced.

Next, as shown in FIG. 9, using the low edge type V-belt (a) in which the mixing ratio of the powder rubber is 20% and the current one in which the powder rubber is not mixed in the specification (a). Abrasion resistance test. That is, a predetermined load is applied to the V belt RE1 wound between the driving pulley P1 and the driven pulley P2 having the same diameter from the inner peripheral side of the belt by the idler pulley P3.
The belt RE1 was rotated at a constant speed in an atmosphere at room temperature while forcibly sliding the belt RE1 at a predetermined slip ratio.

Then, as a result of examining the wear rate after 24 hours, the current wear rate without powder rubber was 2.05%.
In the case where the powder rubber was mixed, the wear rate was 1.60%, indicating that the wear resistance was improved.

[0060]

As described above, according to the power transmission belt according to the first or second aspect of the present invention, powder rubber is mixed into the new rubber of the belt material as a filler, thereby reducing material costs. Can be reduced. Moreover, by recycling the rubber waste of the belt, the belt manufacturing cost can be reduced while considering environmental protection. In addition, by limiting the mixing ratio of the powder rubber to a predetermined ratio or less, it is possible to ensure the ease of operation in the manufacturing process,
Furthermore, it is possible to suppress roughening of the surface of the vulcanized rubber and deterioration of the flexibility .

[Brief description of the drawings]

FIG. 1 is a wrapped type V according to a first embodiment of the present invention.
It is sectional drawing which shows the structure of a belt.

FIG. 2 is a view corresponding to FIG. 1 showing a configuration of a low-edge type V-belt according to a second embodiment.

FIG. 3 is a graph showing a relationship between a screen hole diameter of a pulverizer, a particle diameter of powder rubber, and a fiber length.

FIG. 4 is a graph showing the correlation between the mixing ratio of powder rubber and the tackiness of an unvulcanized rubber sheet.

FIG. 5 is a schematic configuration diagram of a standard bending durability test apparatus.

FIG. 6 is a schematic configuration diagram of a reverse durability test apparatus.

FIG. 7 is a schematic configuration diagram of a high-temperature high-speed durability test apparatus.

FIG. 8 is a schematic configuration diagram of a bending durability test apparatus.

FIG. 9 is a schematic configuration diagram of a wear resistance test apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Cable cord (core wire) 2 Adhesive rubber layer 3 Overcord layer 4 Undercord layer 5 Bottom rubber layer (compression rubber layer) 6 Outer sail cloth 10 Short fiber P1 Drive pulley P2 Follower pulley P3 Idler pulley WB, RE1, RE2 V Belt (transmission belt)

────────────────────────────────────────────────── ─── Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16G 1/00-17/00 B29D 29/10 B29K 21/00 B29K 105: 12 B29K 105: 26

Claims (2)

(57) [Claims] 1. An adhesive rubber layer in which a cord extending in a belt length direction is embedded, and a tension rubber layer and a compression rubber layer provided on an outer surface side and an inner surface side of the belt of the adhesive rubber layer, respectively. In the power transmission belt, at least one of the adhesive rubber layer, the tension rubber layer and the compression rubber layer is a powder rubber formed from the rubber waste of the belt in an unvulcanized state in a belt manufacturing process. The mixing ratio of the powder rubber is such that the layer to be mixed is made of natural rubber, styrene butadiene rubber,
When it is composed of any one of butadiene rubber, highly saturated nitrile rubber, chlorosulfonated polyethylene rubber and alkylated chlorosulfonated polyethylene rubber, the weight ratio is 30% or less, and Wherein the transmission belt is made of chloroprene rubber, the weight ratio is 25% or less. 2. An adhesive rubber layer in which a cord extending in a belt length direction is buried, an overcord layer and an undercord layer respectively provided on the outer and inner belt sides of the adhesive rubber layer, and A power transmission belt comprising: a bottom rubber layer provided on a belt inner surface side of a cord layer; at least one of the adhesive rubber layer, the overcord layer, the undercord layer, and the bottom rubber layer is formed in a belt manufacturing process. In the unvulcanized state, the rubber composition is formed by mixing powder rubber formed from rubber waste of the belt, and the mixing ratio of the powder rubber is such that the layer to be mixed is a natural rubber. , Styrene butadiene rubber,
When it is composed of any one of butadiene rubber, highly saturated nitrile rubber, chlorosulfonated polyethylene rubber, and alkylated chlorosulfonated polyethylene rubber, the weight ratio is 30% or less. Wherein the transmission belt is made of chloroprene rubber, the weight ratio is 25% or less .