JPH09177899A - Transmission belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a compression rubber layer of a V-belt from sagging and cracking by providing a contact rubber layer in which core wires are embedded and a compression rubber layer and forming the compression rubber layer into the composite structure with a low tans δ layer and a high tans δ layer made of a specific alkylation chlorosulfonated polyethylene composition. SOLUTION: In a friction transmission belt such as V-ribbed belt, V-belt, a canvas 2 with its three-layer rubber on the upper face, a contact rubber layer 4 in which a core wire 3 with its high strength and low elongation is arranged, a compression rubber layer 5 which is an elastic body layer, and the canvas 2 with rubber as the lower face are laminated. A compression rubber layer 5 has a low tans δlayer formed of alkylation chlorosulfonated polyethylene composition of which tans δ at a temperature of 100 deg.C and at a vibration frequency of 10Hz is 0.05 to 0.09 and a high tans δlayer formed of alkylation chlorosulfonated polyethylene composition of which tans δ at a temperature of 100 deg.C and at a vibration frequency of 10Hz is higher than that of the low tans δ layer in a layered composite structure.

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, and more particularly to an invention that is advantageous for improving the running life of friction power transmission belts such as V-ribbed belts and V-belts.

[0002]

2. Description of the Related Art In recent years, the ambient temperature in the engine room of automobiles has risen compared to the conventional temperature, and the demand for heat resistance of transmission belts used therein has increased. Therefore, in such a power transmission belt, it has been considered to use a chlorosulfonated polyethylene-based material having excellent heat resistance as the rubber material. However, this type of rubber material has problems in terms of durability and low temperature characteristics (cold resistance), and its improvement is desired.

On the other hand, in Japanese Patent Laid-Open No. 4-212748, an alkylated chlorosulfonated polyethylene (hereinafter referred to as "alkylated chlorosulfonated polyethylene", which has an alkyl group introduced into its main chain to reduce the crystallinity, , AC
The abbreviation "SM" is sometimes used) as the compression rubber of the power transmission belt. That is,
This is intended to improve the low temperature characteristics of the transmission belt by setting the chlorine content of the ACSM to 15 to 35% by weight and the sulfur content to 0.5 to 2.5% by weight.

Further, Japanese Patent Application Laid-Open No. 63-57654 discloses that chlorosulfonated polyethylene is blended with dimaleimide, nickel dithiocarbamate and thiuram polysulfide to improve its compression set resistance.

[0005]

However, the above-mentioned ACSM
In the case of a power transmission belt that uses, if the running (usage) time becomes long, it will be repeatedly subjected to mechanical stimulus, and the deformation of the belt will gradually increase and sink into the pulley, causing so-called sag (permanent distortion). This problem becomes noticeable especially when used under high load or high tension.

The above-mentioned settling is basically caused by deterioration of rubber, and this deterioration is caused by heat. Conventionally, as a factor relating to heat that influences the running life of the transmission belt, the ambient temperature of the transmission belt is known. Also, it has been considered that an external heat factor such as frictional heat generated by friction between the belt and the pulley during traveling of the belt is a problem, and a countermeasure against this is taken.

However, regarding the running life of the power transmission belt, not only the external heat factor is a problem, but the rubber itself constituting the belt generates heat as the belt moves, and the heat is stored inside. It needs to be a problem.
That is, due to internal heat factors such as heat generation and heat storage, the softening / deterioration of the rubber progresses, which is one of the causes of the above-mentioned settling. Then, this heat generation and heat storage becomes remarkable in the compressed rubber layer of the belt, and the belt life is shortened. In other words, even if the heat resistance of the belt against heat as an external factor is improved, the running life of the belt cannot be significantly extended unless the amount of heat generation / heat storage, which is an internal factor, is reduced.

On the other hand, the transmission belt using the ACSM also has a problem that if the running (usage) time becomes long, the belt is cracked as a result of being repeatedly subjected to mechanical stimulus, and the crack is compressed. It easily occurs in the rubber layer. In particular, when the diameter of the pulley around which the power transmission belt is wound is small, the bending deformation of the belt when passing through the pulley becomes large, so that the problem of the above-mentioned cracking becomes significant.

Considering the problems of the settling and the problems of the cracks, the former is that the mechanical energy applied from the outside with the movement of the belt is converted into heat and the compressed rubber layer stores heat inside. On the other hand, in the latter case, the latter causes the mechanical energy to be locally converted into heat and cause localized stress concentration in the compressed rubber layer. Therefore, the heat resistance / heat storage characteristics and the crack resistance characteristics of the belt have a relationship that they change in a contradictory direction such that when one is improved, the other is deteriorated, and there is a problem that it is difficult to achieve both at the same time.

Japanese Unexamined Patent Publication (Kokai) No. 4-212748, which has been cited as showing the prior art, prevents hardening of rubber due to agglomeration of chlorine at a low temperature of -30 ° C. or lower by using ACSM as a rubber material of a transmission belt. However, it does not suggest countermeasures against the above-mentioned settling and cracking.

The present invention has been made in view of the above points, and when the ACSM is used for the compression rubber layer of the transmission belt, both the internal heat factor and the stress concentration described above are taken as countermeasures and the running thereof is performed. The challenge is to extend life.

[0012]

Means for Solving the Problems The present inventor has conducted various studies on the above problems, and as a result of repeating trial production and experiments, various values of tan δ, which is an index of the dynamic viscoelastic property of a polymer, have been obtained. If a transmission belt is manufactured by changing the value, the running life of the belt greatly changes depending on the value of tan δ.
No matter which ACSM composition is used, it is difficult to satisfy both of the above-mentioned contradictory properties with a single composition, and it has been found that it is necessary to take measures from a structural viewpoint, and the present invention has been completed. It is a thing. Hereinafter, the invention according to each claim of the claims will be specifically described.

<Inventions of Claims 1 to 4> The invention according to claim 1 is provided with an adhesive rubber layer and a compression rubber layer for holding the core wire extending in the longitudinal direction of the belt at an appropriate position. The layer has a tan δ at a temperature of 100 ° C. and a frequency of 10 Hz.
And a low tan δ layer formed of an alkylated chlorosulfonated polyethylene composition of 0.05 to 0.09 and a low tan δ at a temperature of 100 ° C. and a frequency of 10 Hz.
A transmission belt characterized in that a high tan δ layer formed of an alkylated chlorosulfonated polyethylene composition having a higher tan δ than the δ layer is formed in a composite structure in which layers are layered in the belt thickness direction. Is.

The invention according to claim 2 is provided with an adhesive rubber layer for holding the core wire extending in the longitudinal direction of the belt at an appropriate position and a compression rubber layer, the compression rubber layer at a temperature of 100 ° C. and a frequency of 10 Hz. A high tan δ layer formed of an alkylated chlorosulfonated polyethylene composition having a tan δ of 0.08 to 0.15 and a tan δ at a temperature of 100 ° C. and a frequency of 10 Hz is higher than that of the high tan δ layer. And a low tan δ layer formed of a low-alkylated chlorosulfonated polyethylene composition are formed in a composite structure in which the layers are layered in the belt thickness direction.

According to a third aspect of the present invention, in the power transmission belt according to the first or second aspect, the compression rubber layer has a two-layer structure of a low tan δ layer and a high tan δ layer. The low tan δ layer has a high
It is characterized in that the tan δ layers are respectively arranged on the sides far from the core wire.

According to a fourth aspect of the present invention, in the power transmission belt according to the first or second aspect, the compression rubber layer has low tan δ layers and high tan δ layers alternately laminated. It is characterized in that it is formed in a multilayer structure.

In each of the above inventions, the alkylated chlorosulfonated polyethylene composition is a chlorosulfonated low-density polyethylene composition having a linear molecular structure. Then, in each of the inventions, the compression rubber layer is made low.
Since the composite structure is composed of the tan δ layer and the high tan δ layer, it is possible to achieve both improved sag resistance and improved crack resistance. Hereinafter, this point will be specifically described.

(Tan δ) First, the tan δ will be described. The dynamic property test of vulcanized rubber (JIS K)
6394), the complex elastic modulus is expressed by the following equation (1). G ^* = G ′ + iG ″ (1) G ^* : Complex shear modulus G ′: Storage modulus (real part of complex shear modulus) G ″: Loss modulus (imaginary part of complex shear modulus)

The angle δ representing the time delay between the applied stress and strain is called the dissipation factor and defined by the following equation (2). tan δ = G ″ / G ′ (2)

This tan δ is a damping term and is a measure of the ratio of the energy dissipated as heat to the maximum energy stored during one cycle of vibration. And
The loss elastic modulus G ″ is directly proportional to the heat dissipated per cycle as shown in the following equation (3). H = πG ″ γ ² (3) H: Heat dissipated per cycle γ: Maximum value of shear strain

As described above, tan δ represents the ease with which the mechanical energy applied to the rubber composition is dissipated as heat. If the value of tan δ is high, the mechanical energy applied from the outside will increase. It is advantageous to improve crack resistance because it reduces stress concentration due to heat, and if the value of tan δ is low, the amount of mechanical energy converted to heat is small, which is advantageous for improving sag resistance. Become.

Therefore, as in the invention according to claim 1 and the invention according to claim 2, the compression rubber layer of the transmission belt has a low tan δ.
When the composite structure of the layer and the high tan δ layer is used, the low tan δ layer can prevent the fatigue, while the high tan δ layer can suppress the occurrence of cracks.

On the other hand, the cracks are mainly generated on the surface of the compressed rubber layer and grow inward, and the above-mentioned settling is not so problematic because heat dissipation to the outside is easy on the surface of the compressed rubber layer. However, this is a particular problem inside the compressed rubber layer where heat dissipation is low and heat is likely to accumulate.

Therefore, in the invention according to claim 3, the ta is
In view of the nature of n δ and the mechanism of occurrence of cracks and fatigue, the tan δ value is low in the layer close to the core wire (hereinafter referred to as the upper layer) in which the compression rubber layer is liable to cause fatigue. The ACSM composition is used, and the ACSM composition having a high tan δ value is used for a layer on the side far from the core wire (hereinafter, referred to as a lower layer) that easily causes cracks.

That is, since the upper layer of the compressed rubber layer is formed of an ACSM composition having a low tan δ value,
Even if the power transmission belt is repeatedly bent by the pulley, the amount of mechanical energy that is internally converted to thermal energy is small, and therefore the amount of internal heat generation and heat storage is high, so the deformation recovery capability is high and the above setback is prevented. It

On the other hand, since the lower layer of the compressed rubber layer is formed of the ACSM composition having a high tan δ value, even if the power transmission belt is repeatedly bent in the pulley, its mechanical energy is easily converted into thermal energy. The stress concentration is low, which is advantageous for preventing cracks.

In the invention according to claim 3, the upper layer of the compression rubber layer is the low tan δ layer and the lower layer is the high tan δ layer. However, in the so-called rear drive in which the pulley is rotationally driven on the rear side of the transmission belt. When a small-diameter pulley is arranged on the back surface side, cracking on the side of the compressed rubber layer close to the core becomes a problem. Therefore, in that case, the upper layer of the compression rubber layer may be a high tan δ layer, and the lower layer may be a low tan δ layer.
The arrangement of layers and low tan δ layers is not excluded.

Further, in the invention according to claim 4, a low tan δ layer formed by an ACSM composition having a low tan δ value and a high tan δ layer formed by an ACSM composition having a high tan δ value Are alternately stacked. In this case low ta
Since the n δ layer generates less heat and heat when the transmission belt is repeatedly bent by the pulleys, the deformation recovery ability of the compression rubber layer is maintained even if there is a high tan δ layer above and below it.
That is, even if the high tan δ layer has heat generation / accumulation, the high ta
The low tan δ layer suppresses the deterioration of the n δ layer.

On the other hand, the low tan δ layer is more disadvantageous than the high tan δ layer in preventing cracks, but the high tan δ layer alleviates stress concentration that causes cracks in the low tan δ layer. Alternatively, the high tan δ layer prevents cracks from growing from the low tan δ layer.

In the present invention, the low tan δ layer and the high ta are
Even when alternately stacking n δ layers, it is preferable to dispose the high tan δ layer in the lowermost layer that easily causes cracks, and arrange the low tan δ layer in the uppermost layer that easily causes fatigue. Is preferred.

In each of the above inventions, the ratio of the low tan δ layer and the high tan δ layer of the compression rubber layer can be variously set according to the use conditions or required characteristics of the transmission belt. The proportion of the low tan δ layer in the compressed rubber layer is preferably 5 to 95% by volume.

(Upper limit / lower limit of tan δ) Low ta of compressed rubber layer
In the case of the ACSM composition forming the n δ layer, ta is measured at a temperature of 100 ° C. and a frequency of 10 Hz from the viewpoint of suppressing the above settling.
The upper limit of n δ is preferably 0.09, and more preferably 0.08. The lower limit of tan δ is preferably about 0.05 because if the value is too low, the problem of cracking will occur even if the low tan δ layer is on the upper side.

ACS for forming high tan δ layer of compressed rubber layer
In the case of the M composition, the lower limit of tan δ at a temperature of 100 ° C. and a frequency of 10 Hz is preferably 0.08, and more preferably 0.09, from the viewpoint of suppressing the occurrence of cracks. If the upper limit of the tan δ is too high, even if the high tan δ layer is on the lower side, the above-mentioned settling problem will occur.
It is preferable to set it to 3.

Here, the value of tan δ is set to a temperature of 100 ° C.,
The frequency of 10 Hz is set because the operating environment and conditions of a general transmission belt (for example, a timing belt of an automobile) are taken into consideration. Especially, regarding the frequency, the transmission belt is bent by passing through a pulley. This is in consideration of the extended cycle.

<Inventions of Claims 5 and 6> The invention according to claim 5 is the transmission belt according to any one of claims 1 to 4, wherein the low tan δ is low.
The alkylated chlorosulfonated polyethylene of the layer has a sulfur content of 0.8 to 2.0% by weight, and the sulfurized content of the alkylated chlorosulfonated polyethylene of the high tan δ layer is the same as that of the low tan δ layer. It is characterized by being less than the sulfur content.

According to a sixth aspect of the present invention, in the transmission belt according to any one of the first to fourth aspects, the sulfur content of the alkylated chlorosulfonated polyethylene in the high tan δ layer is 0. 0.5 to 0.8% by weight, and the sulfur content of the alkylated chlorosulfonated polyethylene of the low tan δ layer is higher than the sulfur content of the high tan δ layer.

(Regarding Sulfur Content and Chlorine Content) The sulfur content is closely related to the amount of chlorosulfone groups in the molecule, that is, the number of crosslinking points, and the larger the amount, the denser the crosslinking. Therefore, the sulfur content is tan of the ACSM composition.
This is a major factor in changing δ.

In the invention according to claim 5, the lower limit of the sulfur content of the ACSM forming the low tan δ layer of the compressed rubber layer is 0.8% by weight, when the sulfur content is less than the above. This is because the value of tan δ becomes high and it becomes difficult to set it to the above low value. On the other hand, the reason why the upper limit of the sulfur content is 2.0% by weight is that if the sulfur content is higher than this, it is advantageous for lowering the tan δ, but the compounding of other compounding agents This is because the design becomes difficult.

On the other hand, in the invention according to claim 6, the upper limit of the sulfur content of ACSM forming the high tan δ layer of the compressed rubber layer is 0.8% by weight, because the sulfur content is larger than this. This is because the value of tan δ becomes low and it becomes difficult to set the value to the high value. On the other hand, the lower limit of the sulfur content of 0.5% by weight is advantageous in increasing the tan δ when the sulfur content is lower than this, but the compounding of other compounding agents This is because the design becomes difficult.

As described above, the value of tan δ changes depending on the sulfur content, but not only the sulfur content but also the chlorine content is a factor of change. However, this chlorine content is
It has a closer relationship with the crystallinity of SM, and the higher the chlorine content, the stronger its rubber elastic properties, but the worse the low temperature properties. Therefore, regarding this chlorine content,
It is suitable to set it to 5 to 35% by weight, and more desirably to 25 to 32% by weight. That is, when the upper limit of the chlorine content is set to 35% by weight, and more preferably 32% by weight, the cohesive energy of chlorine can be suppressed to a low level, which is advantageous in preventing the rubber from curing and the cold resistance of the belt. Is improved. Also, the lower limit of the chlorine content is 15% by weight,
More preferably, it is set to 25% by weight, which is advantageous in ensuring the oil resistance and mechanical strength of the rubber.

However, it should be noted that even the transmission belt described in Japanese Patent Application Laid-Open No. 4-212748 mentioned above as a prior art has the ACSM used for this.
Although the sulfur content and chlorine content of tan δ are specified, the value of tan δ cannot be specified only by this sulfur and chlorine content.

That is, the value of tan δ is not only determined by the above-mentioned sulfur content and chlorine content, but also changed by the kind and amount of the crosslinking agent and other compounding agents.

For example, tan δ can be set to a predetermined high value by decreasing the blending amount of the crosslinking agent and the crosslinking accelerator, but the tan δ can also be increased by increasing the blending amount of carbon black or the process oil. δ can be set to a high value. However, if these amounts are changed, other rubber physical properties of the belt change accordingly,
It is necessary to adjust the amount of each compounding agent in consideration of various rubber physical properties required for the belt.

<Invention of Claim 7> The present invention is the transmission belt according to claim 5 or 6, wherein the low tan δ-layer alkylated chlorosulfonated polyethylene composition is alkylated. 1 to 7 parts by weight of N, N'-m-phenylene dimaleimide and 0.1 to 4.0 parts by weight of dipentamethylene thiuram tetrasulfide are mixed with 100 parts by weight of chlorosulfonated polyethylene. The high tan δ layer of the alkylated chlorosulfonated polyethylene composition contains N, N′-m-based on 100 parts by weight of the alkylated chlorosulfonated polyethylene.
0.2 to 5.0 parts by weight of phenylene dimaleimide and 0.1 to 4 parts by weight of dipentamethylene thiuram tetrasulfide.
0 parts by weight and 0.1 to 5.0 parts by weight of pentaerythritol (pentaerythritol) are blended.

In the low tan δ layer ACSM composition, N, N'-m-phenylenedimaleimide acts as a cross-linking agent, and if the content is less than 1 part by weight, insufficient vulcanization occurs. On the other hand, if this amount exceeds 7 parts by weight, tan δ
However, the problem of cracking occurs. Therefore, the compounding amount is set within the above range,
In order to set tan δ to a predetermined low value while performing appropriate vulcanization, it is more preferable to set the compounding amount to 2 to 4 parts by weight.

The above-mentioned dipentamethylene thiuram tetrasulfide is an accelerator for promoting cross-linking when used in combination with the above N, N'-m-phenylene dimaleimide. However, if it exceeds 4 parts by weight, tan δ will be considerably low, and the problem of cracking will occur. Therefore, the compounding amount of this accelerator is set within the above range, and a more preferable range is 1 to 2 parts by weight.

On the other hand, in the high tan δ layer ACSM composition, when the amount of the N, N′-m-phenylenedimaleimide compounded is less than 0.2 parts by weight, vulcanization is insufficient. On the other hand, when this amount exceeds 5 parts by weight, it becomes difficult to set the value of tan δ to the above-mentioned high value, which is disadvantageous for crack prevention. From such a viewpoint, the compounding amount is set in the above range, and a more preferable range is 1 to
3 parts by weight.

If the amount of dipentamethylene thiuram tetrasulfide blended is less than 0.1 part by weight, the expected accelerating effect cannot be obtained, and if it exceeds 4 parts by weight, tan δ becomes considerably low. Therefore, the compounding amount of this accelerator is set within the above range, and a more preferable range is 1 to 2 parts by weight.

The above-mentioned pentaerythrite is considered to improve flex fatigue resistance by optimizing the cross-linking state of ACSM while optimizing the cross-linking of ACSM, while its detailed function is unknown.

That is, ACSM can have various cross-linking structures, the N, N'-m-phenylene dimaleimide is maleimide cross-linking, the dipentamethylene thiuram tetrasulfide is sulfur cross-linking, and examples thereof will be described later. When a metal oxide (magnesium oxide) is used as the metal oxide, metal oxide cross-linking occurs, and a plurality of kinds of cross-linking structures coexist due to the combined use of these plural cross-linking agents or accelerators.

On the other hand, whether or not the above-mentioned pentaerythritol is compounded seems to affect the existence ratio of each of the above-mentioned cross-linking structures to make the rubber physical properties completely different. Particularly, depending on the composition as in the present invention. The flex fatigue resistance of the rubber is significantly improved.

If the blending amount of pentaerythritol is less than 0.1 parts by weight, the expected improvement effect cannot be obtained.
If it exceeds 5 parts by weight, crosslinking will proceed too much and flex fatigue resistance cannot be obtained. Therefore, the blending amount is set within the above range, and a more preferable range is 1 to 4 parts by weight.

<Invention of Claim 8> This invention is characterized in that, in the transmission belt described in claim 7, short fibers are mixed in the compressed rubber layer.

In the present invention, the short fibers are mixed in the ACSM composition, which is advantageous for preventing cracks and sagging.

Thus, in the case of the rubber material in which the short fibers are mixed in the ACSM composition as described above, if the orientation direction of the short fibers is made constant, the mechanical characteristics (mechanical properties) between the direction and the direction perpendicular thereto are increased. It is known that a large difference occurs in the characteristics.

When short fibers are added to the compressed rubber layer in the friction transmission belt, the short fibers are generally oriented in the direction perpendicular to the friction surface with the pulley.

As the short fibers, organic fibers such as polyester fibers, nylon fibers, aramid fibers or inorganic fibers can be used.

<Inventions of Claims 9 and 10> In the invention of claim 9, the transmission belt described in claim 8 is a V-belt of a low edge type.
According to the invention of claim 8, the transmission belt described in claim 8 is a V-ribbed belt of a low edge type.

In each of the inventions, the transmission belt of the above-mentioned claim 8 is limited to the low-edge type, so that in this type, the problems of the heat generation / accumulation of the compressed rubber layer and the problem of cracking become remarkable. Because.

<Others> (Regarding compounding agent) The ACSM composition of each of the above claims is
As mentioned above regarding the compounding agent in connection with the explanation of tan δ, reinforcing agents such as carbon black, fillers, acid acceptors, plasticizers, tackifiers, processing aids, antiaging agents, active agents A general rubber compound such as an agent may be arbitrarily selected and compounded. MAF, F as carbon black
EF, GPF, SRF, etc., magnesium oxide, calcium hydroxide, magnesium oxide-aluminum oxide solid solution, etc. as acid acceptors, process oil, dioctyl adipate (DOA), dioctyl separate (DOS), poly as softeners. Ether plasticizers, tackifiers such as coumarone resin, phenol resin, and alkylphenol resins, and antioxidants such as nickel butyldithiocarbamate (NBC) and 2,2,4-trimethyl-1,2-diene. Hydroquinoline condensate (TMD
Q), 6-ethoxy-2,2,4-trimethyl-1,2
-A condensate of dihydroquinoline (ETMDQ) and the like can be used respectively.

When a magnesium oxide-aluminum oxide solid solution is used as the above acid acceptor, the blending amount is ACS.
1 to 50 parts by weight, preferably 4 to 100 parts by weight of M
-20 parts by weight. If the amount of this magnesium oxide-aluminum oxide solid solution is less than 1 part by weight, hydrogen chloride generated during crosslinking cannot be sufficiently removed, so that the crosslinking points of ACSM are reduced and a predetermined vulcanized product is obtained. If the amount exceeds 50 parts by weight, the Mooney viscosity becomes extremely high, which causes a problem in processing and finishing.

As a method for mixing the ACSM and the compounding agent, kneading can be carried out by an appropriate known means and method (for example, using a Banbury mixer, a kneader or the like).

Regarding the above-mentioned core wire, polyester fiber,
It can be formed by a cord having high strength and low elongation made of aramid fiber, glass fiber or the like.

On the other hand, the adhesive rubber layer has a heat resistance and a chloroprene rubber composition which adheres well to core fibers such as polyester fiber, aramid fiber and glass fiber, and hydrogenated nitrile having a hydrogenation rate of 80% or more. A rubber composition, an ACSM composition, a CSM composition, etc. can be used.

The core wire may be treated with an adhesive for the purpose of improving the adhesiveness with the adhesive rubber. For such an adhesive treatment, fibers are treated with resorcin-formalin-
After being immersed in latex (RFL solution), it is generally heated and dried to uniformly form an adhesive layer on the surface.

The transmission belt according to the present invention is not limited to the V-belt of the low edge type, but may be another transmission belt such as a flat belt, and the canvas with rubber covers the entire circumference of the belt. A covered type belt may be used.

[0067]

BEST MODE FOR CARRYING OUT THE INVENTION

<Preferred Embodiment of Belt Structure> FIG. 1 shows a V-belt 1 as an example of a transmission belt. This V
The belt 1 includes three layers of rubber-coated canvas 2 on the upper surface, an adhesive rubber layer 4 on which a core wire 3 having high strength and low elongation is arranged, a compression rubber layer 5 as an elastic layer, and a rubber-coated canvas 2 on the lower surface. Is a lower edge type in which the side surfaces of these laminated members are exposed. The compressed rubber layer 5 has a low tan
an upper layer 5a formed by the ACSM composition of δ,
has a two-layer structure of a lower layer 5b formed of an ACSM composition of tan δ, and short fibers 6, 6, ... Are mixed in the upper and lower layers 5a, 5b while being oriented in the belt width direction.

FIG. 2 shows a V-ribbed belt 7 as another example of the transmission belt. This V-ribbed belt 7
Comprises a two-layer rubber canvas 2 on the upper surface, an adhesive rubber layer 4 on which a high-strength, low-extension core wire 3 is arranged, and a compression rubber layer 8 which is an elastic layer, which are laminated one above the other. These are low edge types in which the side surfaces of these laminated members are exposed.
The compressed rubber layer 8 has a plurality of ribs 9 and has an upper layer 8a formed of an ACSM composition having a low tan δ and a high tan.
It has a two-layer structure with the lower layer 8b formed by the ACSM composition of δ. In addition, each layer 8a of the compressed rubber layer 8,
Short fibers 6, 6, ... Are mixed in 8b by orienting them in the belt width direction.

The V-belt 11 shown in FIG. 3 has a compressed rubber layer 12 having a multi-layer structure, and the other constitution is the V-belt shown in FIG.
Same as belt 1. The compressed rubber layer 12 comprises a plurality of low tan δ layers 1 formed of a low tan δ ACSM composition.
2a and a plurality of high tan δ layers 12b formed of an ACSM composition having a high tan δ, and the low tan δ layer 12 as the uppermost layer.
a is arranged and the high tan δ layer 12b is arranged at the lowermost layer, and the layers are alternately laminated.
... are mixed with the short fibers 6, 6 ... Oriented in the belt width direction.

The V-ribbed belt 13 shown in FIG. 4 has a compressed rubber layer 14 having a multi-layer structure, and the other structure is the same as that of the V-ribbed belt 7 in FIG. Compressed rubber layer 14
Includes a plurality of low tan δ layers 14a having a plurality of ribs 15 and formed by an ACSM composition having a low tan δ, and
Multiple high ta formed by ACSM composition of tan δ
n δ layers 14b are alternately laminated so that the low tan δ layer 14a is arranged at the uppermost layer and the high tan δ layer 14b is arranged at the lowermost layer, and the short fibers 6 are formed in each of the layers 14a and 14b. , 6 ... are mixed while being oriented in the belt width direction.

<Relationship between sulfur content and tan δ> Four types of ACSM (S = 0.5%, 0.7) having different sulfur contents.
%, 0.8% and 1.0%) were prepared. Then, as shown in the formulation in Table 1, test pieces (without short fibers) were prepared from the ACSM compositions using these ACSMs, and the tan δ values thereof were measured according to JIS K 6394 to a test piece temperature of 100 ° C. It was determined at a frequency of 10 Hz. In the table, the numerical value of each component is the addition amount (part by weight). This point is the same in Tables 2 to 7 described later.

[0072]

[Table 1]

Barnock PM (trade name of N, N'-m-phenylene dimaleimide) manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. was used as the cross-linking agent, and Noxeller TRA (dipentamethylene thiuram) of the same company was used as the accelerator. The trade name of tetrasulfide) was used. In preparing the test piece, the rubber material was kneaded with a Banbury mixer. Vulcanization of the rubber material was carried out under generally accepted conditions (160 ° C. × 40 minutes).

Further, a test piece (with short fibers) was prepared by mixing short fibers in an ACSM composition having the same composition as the above-mentioned test piece in a fixed direction, and the anti-parallelism (short fiber orientation direction) was prepared. Tan δ in the direction orthogonal to the) was measured under the same temperature and frequency conditions. As the short fibers, aramid short fibers having a denier of 2 mm and a fiber length of 3 mm were used, and the mixing amount of the short fibers was 12 parts by weight or 15 parts by weight per 100 parts by weight of ACSM. The short fibers were mixed with an open roll. The results are shown in Table 1.

Table 1 shows that the value of tan δ decreases as the sulfur content of ACSM increases.

<Rubber material of two-layer structure compression rubber layer> (Relationship between two-layer structure and belt life) C1 to C in Table 1 above
Each V-belt having a ratio of 1 to 4 in which each rubber material (having short fibers) of No. 4 is used as a compression rubber layer (single layer), and the rubber materials of C1 to C4 (having short fibers) are appropriately combined into two layers. Each of V belts of actual 1 to actual 3 and ratio 5 in which a compressed rubber layer having a structure was formed was prepared, and the running life of each was investigated. These sample V belts were of the low edge type shown in FIG. Regarding the compressed rubber layer having a two-layer structure, the ratio of the lower layer was 30% by volume of the entire compressed rubber layer. The belt length is 930 mm in each case.

Further, regarding the above-mentioned test belt, a core fiber made of polyester fiber was used. This core wire was impregnated with an adhesive solution obtained by dissolving an isocyanate compound in a solvent, heated and dried, and then coated with an RFL solution and heated and dried. The RFL solution was 430.5 parts by weight of RF solution (resorcin-formalin solution), 787.4 parts by weight of 2.3-dichlorobutadiene, 716.4 parts by weight of water,
And wetting agent (sodium dioctyl sulfosuccinate 2
%) 65.8 parts by weight. As the rubber material of the adhesive rubber layer, 100 parts by weight of ACSM, 40 parts by weight of carbon black, 2 parts by weight of antioxidant, 2 parts by weight of accelerator, 8 parts by weight of MgO—Al ₂ O ₃ solid solution, and N—N ′.
ACS consisting of 1 part by weight of -m-phenylene dimaleimide
The M composition was used.

The constitution of the above-mentioned sample belt is an example and should not be construed as limiting the present invention.

In the running life test, as shown in FIG. 5, the test V-belt 20 is wound around the drive pulley 21, the driven pulley 22 and the idle pulley 23, and the belt 20 is subjected to the following conditions.
Is measured, and the time (unit: hr) until cracks occur in the compressed rubber layer or sag occurs and transmission failure occurs is measured.

-Belt running test conditions-Diameter of drive pulley 21; 125 mm Diameter of driven pulley 22; 125 mm Diameter of idle pulley 23; 65 mm Winding angle θ of sample belt 20; 90 degrees Load W; 80 kgf Ambient temperature; 25 ℃ Drive pulley 21 rotation speed: 4800 rpm load: 10 PS

The test results are shown in Table 2 together with the composition of each test material.

[0082]

[Table 2]

According to the table, the belts 1 to 3 in which the compressed rubber layer has a two-layer structure have a much longer belt running life than the compressed rubber layer having a single layer structure in the ratios 1 to 4. Ratio 1 and ratio 2 are
It is considered that the low value of tan δ causes the settling of the compressed rubber layer early, and the ratios 3 and 4 indicate that the value of tan δ is high, causing the early cracking of the compressed rubber layer. The ratio 5 also has the same two-layer structure of the compressed rubber layer as the examples 1 to 3, but the belt running life is short. In the case of ratio 5, unlike actual 1 to actual 3, tan δ in the upper layer is higher than tan δ in the lower layer.

From the above, when the tan δ of the upper layer of the compression rubber layer is lower and the tan δ of the lower layer is higher as in Examples 1 to 3, sag and cracking of the compression rubber layer occur. It can be seen that the belt running life is extended by being suppressed. In addition, among Examples 1 to 3, Example 1 having the lowest tan δ value in the upper layer and the example having the highest tan δ value in the lower layer showed the best result.

(Formulation of Suitable Blending of Lower Layer ACSM Composition) A test V-belt having the same composition as the upper layer of the above-mentioned Ex. 1 with the composition of the lower layer ACSM composition being appropriately changed was prepared. They were created and their belt running life was measured. In addition, with respect to the test pieces prepared by using the ACSM composition having the same composition as these lower layers (however, there is no short fiber),
The value of tan δ was calculated. These measuring methods and conditions are the same as those described above. The results are shown in Table 3.

[0086]

[Table 3]

-Effect of Crosslinking Agent Blending Quantity-Executive Nos. 4 to 7, Ratio 6 and Ratio 7 are examples in which only the blending quantity of the crosslinker is different from each other.
δ is low. From this, the amount of the crosslinking agent blended
It can be seen that affecting the value of tan δ and reducing the blending amount is advantageous in increasing the value of tan δ in the lower layer.

Looking at the belt running life, the life of Examples 4 to 7 is significantly longer than that of Ratio 6 and Ratio 7. In the case of ratio 6, the amount of the cross-linking agent is 0.1 part by weight and the value of tan δ is as high as 0.175, but it is short-lived. The ratio 6 is a transmission failure due to settling. From this, even in the lower layer, if the amount of the crosslinking agent is small and the value of tan δ becomes too large,
It turns out that the problem of sagging occurs. Therefore, it is necessary to determine the compounding amount of the crosslinking agent so that the value of tan δ becomes lower than 0.175. Further, as in the case of the ratio 7, the amount of the crosslinking agent blended is 6
When the value of tan δ is as low as 0.079 due to the presence of parts by weight, cracks are generated early, so that the value of tan δ is 0.07.
It is necessary to determine the amount of the cross-linking agent to be higher than 9.

-Influence of Accelerator Mixing Amount-Examples 8, 9 and 9 are examples in which only the compounding amount of the accelerator is different from each other, but the value of tan δ decreases as the compounding amount increases. There is. In addition, Example 6 and Ratio 8 are also examples in which only the compounding amounts of the accelerators are different from each other, but similarly, Example 6 with a larger compounding amount has a lower tan δ value. From this, it can be seen that the blending amount of the accelerator affects the value of tan δ, and it is advantageous to reduce the blending amount to increase the value of tan δ.

Looking at the belt running life, Example 6 and Example 8
And, the real 9 has a significantly longer life than the ratio 8 and the ratio 9. Ratio 8
Has a high accelerator blending amount of 0 and a high tan δ value of 0.155, but is short-lived. This ratio 8 is a transmission failure due to settling. From this, it can be seen that even in the lower layer, if the blending amount of the accelerator is small and the value of tan δ becomes too large, the durability of the belt is disadvantageous in terms of the above-mentioned settling. Therefore, it is necessary to determine the blending amount of the accelerator so that the value of tan δ becomes lower than 0.155. Also,
When the tan δ value is as low as 0.071 due to the compounding amount of 5 parts by weight as in the case of the ratio 9, cracks are generated early, so that the tan δ value should be higher than 0.071. It is necessary to determine the amount of accelerator compounded.

-Influence of Pentaerythritol Blending Amount-Exemplified Examples 6, Exemplified Example 10, Exemplified Example 10, Exemplified Example 11, Exemplified Example 11 and Ratio 11 are different from each other only in the blending amount of pentaerythritol. As a result, the value of tan δ decreases.
From this, it is understood that the blending amount of pentaerythritol has an influence on the value of tan δ, and that it is better to reduce the blending amount of tan δ.
It can be seen that it is advantageous in increasing the value of δ.

Looking at the belt running life, the lifes of 6, 7, and 11 are much longer than those of 10 and 11.
A ratio of 10 means that the blending amount of pentaerythritol is zero and tan
The value of δ is as high as 0.182, but it is short-lived. This ratio 10
It is something that has become a poor transmission due to fatigue. From this, it can be seen that even in the lower layer, if the blending amount of pentaerythritol is small and the value of tan δ is too large, the durability of the belt is disadvantageous in terms of the above-mentioned settling. Therefore, it is necessary to determine the compounding amount so that the value of tan δ becomes lower than 0.182. Further, when the value of tan δ is as low as 0.075 and the compounding amount is 6 parts by weight as in the case of ratio 11, cracks are generated early, so that the value of tan δ becomes higher than 0.075. Therefore, it is necessary to determine the blending amount.

(Determination of Suitable Blending of ACSM Composition of Upper Layer) A test V-belt having a lower layer of the compression rubber layer having the same structure as the lower layer of Ex. 1 and appropriately changing the blending of the ACSM composition of the upper layer was prepared. They were created and their belt running life was measured. In addition, with respect to the test pieces (however, without short fibers) prepared by the ACSM composition having the same composition as those of these upper layers,
The value of tan δ was calculated. These measuring methods and conditions are the same as those described above. The results are shown in Table 4.

[0094]

[Table 4]

-Influence of Crosslinking Agent Blending Amount-Examples 12 to 15, Ratio 12 and Ratio 13 are examples in which only the blending amount of the crosslinking agent is different from each other. As it becomes, tan δ becomes lower.

Looking at the belt running life, actual 12 to actual 15
Has a much longer life than the ratios 12 and 13. The ratio 13 was 8 parts by weight of the cross-linking agent and had a tan δ value of 0.04.
It is as low as 2, but short-lived. This ratio 13 is a transmission failure due to cracks. From this, it can be seen that even in the upper layer, if the blending amount of the crosslinking agent becomes excessive and the value of tan δ becomes too low, the problem of cracking will occur. Therefore, it is necessary to determine the compounding amount of the crosslinking agent so that the value of tan δ is higher than 0.042. Further, when the compounding amount of the cross-linking agent is zero and the value of tan δ is as high as 0.095 as in the case of the ratio 12, settling occurs early, so that the value of tan δ becomes lower than 0.095. It is necessary to determine the amount of the cross-linking agent to be added.

-Regarding Effect of Accelerator Blending Amount-Exemplary 16, Exemplified 17, Ratio 14 and Ratio 15 are examples in which only the blending amount of the accelerator is different from each other. However, as in Table 3, the blending amount is large. The value of tan δ decreases as the value becomes higher.

Looking at the belt running life, the life of Examples 16 and 17 is much longer than that of 14 and 15. Ratio 1
No. 5 had an accelerator content of 6 parts by weight and a tan δ value of 0.
Although low as 039, it is short-lived. The ratio of 15 is a transmission failure due to cracks. From this, it can be seen that, even in the upper layer, if the amount of the accelerator compounded is excessive and the value of tan δ becomes too low, the durability of the belt is disadvantageous in terms of the cracks. Therefore, the value of tan δ is 0.
It is necessary to determine the compounding amount of the accelerator so that it becomes higher than 039. Further, when the accelerator blending amount is zero and the value of tan δ is as high as 0.102 as in the case of ratio 14, fatigue occurs early, so that the value of tan δ becomes lower than 0.102. It is necessary to decide the amount of the accelerator compounded.

<Rubber Material of Multi-Layered Compressed Rubber Layer> (Relationship Between Multi-Layered Structure and Belt Life) C1 to C in Table 1 above
Each of the V-belts of Ex. 18 to Ex. 21 in which a compressed rubber layer having a multi-layer structure was formed by appropriately combining the rubber materials of 4 (having short fibers) was prepared, and the running life of each of them was examined. These test V belts are of the low edge type shown in FIG. 3, all have a belt length of 930 mm, and the core wire and the adhesive rubber layer have the same structure as the above-mentioned two-layer structure test V belt. The method and conditions for measuring the belt running life are the same as those described above. The results are shown in Table 5. In the table,
“Low δ” in the layer type column means a low tan δ layer,
“High δ” refers to the high tan δ layer. This also applies to Tables 6 and 7 described later.

[0100]

[Table 5]

According to the table, the belt running life is C1 rubber material (the ACSM composition has the highest tan δ) and C
2 rubber material (the lowest tan δ of ACSM composition)
Fruit 18 and Fruit 21 which are a combination of and have the longest life,
Tan δ and high tan of ACSM composition forming low tan δ layer
The belt running life becomes shorter as the difference from the tan δ of the ACSM composition forming the δ layer becomes smaller.

(Determination of Suitable Mixing of ACSM Composition for High tan δ Layer) The low tan δ layer of the compressed rubber layer was used as the low ta of the above-mentioned Example 18.
Test V belts having the same constitution as the n δ layer and having the composition of the ACSM composition of the high tan δ layer appropriately changed were prepared, and their running lives were measured. Also, these high tan δ
The value of tan δ was determined for a test piece prepared with the ACSM composition having the same composition as the layer (however, without short fibers).
These measuring methods and conditions are the same as those described above. The results are shown in Table 6.

[0103]

[Table 6]

-Influence of Crosslinking Agent Blending Amount-Exemplary 22 to Exemplified 25, Ratio 16 and Ratio 17 are obtained by changing the value of tan δ by making only the blending amount of the crosslinking agent different from each other. Looking at the belt running life, actual 22 to actual 25 have a ratio of 1
6 and the ratio 17 are much longer. A ratio of 16 is 0.1 parts by weight of the cross-linking agent and a tan δ value of 0.175.
And high, but short-lived. This ratio 16 is a transmission failure due to settling. From this, it can be seen that even in a high tan δ layer, if the blending amount of the cross-linking agent is small and the value of tan δ becomes too high, the problem of sag occurs. Therefore, it is necessary to determine the compounding amount of the crosslinking agent so that the value of tan δ becomes lower than 0.175. Further, as in the case of the ratio 17, the amount of the cross-linking agent was 6 parts by weight and the tan δ value was 0.079.
If it becomes lower, cracks will be generated earlier, so it is necessary to determine the amount of the cross-linking agent so that the value of tan δ becomes higher than 0.079.

-Influence of Accelerator Blending Amount-Examples 26, 27 and ratio 19 are obtained by changing the value of tan δ while making only the blending amount of the accelerators different from each other. Actual 24 and ratio 18 are also those in which the value of tan δ is changed by making only the compounding amounts of the accelerators different from each other. Looking at the belt running life, Example 24, Ex. 26 and Ex. 27 have markedly longer lives than Ratio 18 and Ratio 19. The ratio 18 has a high accelerator blending amount of 0 and a high tan δ value of 0.155, but has a short life. This ratio 18 is a transmission failure due to settling. From this, it can be seen that even in the high tan δ layer, if the amount of the accelerator is too small and the value of tan δ becomes too high, the durability of the belt will be disadvantageous in terms of the above-mentioned settling. Therefore, it is necessary to determine the blending amount of the accelerator so that the value of tan δ becomes lower than 0.155. Further, when the tan δ value is as low as 0.071 due to the accelerator content of 5 parts by weight as in the case of ratio 19, cracks occur early, so the tan δ value becomes higher than 0.071. Therefore, it is necessary to determine the blending amount of the accelerator.

-Influence of Pentaerythritol Blending Amount- Exact 24, Exact 28, Exact 29, Ratio 20 and Ratio 21 are different from each other only in the amount of pentaerythritol mixed.
The value of δ is changed. Looking at the belt running life,
Actual 24, actual 28, and actual 29 have a significantly longer life than the ratio 20 and the ratio 21. In the case of ratio 20, the blending amount of pentaerythritol is zero and the value of tan δ is as high as 0.182, but it is short-lived. This ratio 20 is a transmission failure due to settling. From this, it can be seen that even in the high tan δ layer, if the blending amount of pentaerythritol is small and the value of tan δ becomes too large, the durability of the belt will be disadvantageous in terms of the above-mentioned settling. Therefore, it is necessary to determine the compounding amount so that the value of tan δ becomes lower than 0.182. In addition, the ratio is 6 parts by weight like the ratio 21 and the tan
When the value of δ is as low as 0.075, cracks occur early, so it is necessary to determine the compounding amount so that the value of tan δ becomes higher than 0.075.

(Determination of Suitable Blending of ACSM Composition of Low tan δ Layer) The high tan δ layer of the compressed rubber layer was used as the high ta of the above-mentioned Example 18.
Test V belts having the same structure as the n δ layer and having the low tan δ layer of the ACSM composition changed as appropriate were prepared, and their running lives were measured. Also, these low tan δ
The value of tan δ was determined for a test piece prepared with the ACSM composition having the same composition as the layer (however, without short fibers).
These measuring methods and conditions are the same as those described above. The results are shown in Table 7.

[0108]

[Table 7]

-Influence of Crosslinking Agent Blending Amount-Examples 30 to 33, Ratio 22 and Ratio 23 are obtained by changing the value of tan δ while making only the blending amount of the crosslinking agent different from each other. Looking at the belt running life, the actual 30 to the actual 33 are 2
2 and the life is much longer than 23. In the case of the ratio 23, the compounding amount of the crosslinking agent was 8 parts by weight and the value of tan δ was as low as 0.042, but it was short-lived. This ratio 23 is a transmission failure due to cracks. From this, it is understood that even in the low tan δ layer, if the blending amount of the cross-linking agent becomes excessive and the value of tan δ becomes too low, the problem of cracking will occur. Therefore, it is necessary to determine the compounding amount of the crosslinking agent so that the value of tan δ is higher than 0.042. Further, when the compounding amount of the cross-linking agent is zero and the value of tan δ is as high as 0.095 as in the case of the ratio 22, settling occurs early, so that the value of tan δ becomes lower than 0.095. It is necessary to determine the amount of the cross-linking agent to be added.

-Influence of Accelerator Blending Amount-Exact 34, Exact 35, Ratio 24 and Ratio 25 are obtained by changing the value of tan δ while making only the accelerator blending amount different from each other. Looking at the belt running life, Example 34 and Example 35
Has a significantly longer life than ratios 24 and 25. A ratio of 25 is 6 parts by weight of the accelerator and the tan δ value is 0.03.
It is as low as 9, but short-lived. This ratio 25 is a transmission failure due to cracks. From this, it can be seen that even in the low tan δ layer, if the amount of the accelerator compounded is excessive and the tan δ value becomes too low, the durability of the belt is disadvantageous in terms of the cracks. Therefore, it is necessary to determine the compounding amount of the accelerator so that the value of tan δ becomes higher than 0.039. Further, when the compounding amount of the accelerator is zero and the value of tan δ is as high as 0.102, as in the case of the ratio 24, fatigue occurs early, so that the value of tan δ becomes lower than 0.102. It is necessary to decide the amount of the accelerator compounded.

[0111]

According to the inventions of claims 1 and 2, since the compression rubber layer of the transmission belt has a composite structure of a low tan δ layer and a high tan δ layer, the low tan δ layer is used to settle. It is possible to suppress the occurrence of cracks by the high tan δ layer while preventing the above, and it is possible to improve the sag resistance and the crack resistance of the compressed rubber layer at the same time.

According to the invention of claim 3, since the compression rubber layer of the power transmission belt has an upper and lower two-layer structure, the upper layer is a low tan δ layer, and the lower layer is a high tan δ layer, the resistance of the compression rubber layer is reduced. This is advantageous in achieving both sag and crack resistance.

According to the invention of claim 4, the compression rubber layer of the power transmission belt has a multi-layer structure in which low tan δ layers and high tan δ layers are alternately laminated. This is advantageous in achieving both improvement of sag and improvement of crack resistance.

According to the invention of claim 5, in the power transmission belt according to any one of claims 1 to 4, the low tan δ layer has a sulfur content of 0.8 to 0.8. 2.0% by weight, the above high tan δ layer ACSM
Since the sulfur content in the low tan δ layer was made lower than the sulfur content in the low tan δ layer, tan δ in the low tan δ layer was set to a desired value, which is advantageous in combining this with the high tan δ layer. Become.

According to the invention of claim 6, in the transmission belt according to any one of claims 1 to 4, the high tan δ layer has a sulfur content of 0.5 to 0.5. 0.8 wt%, ACSM of the above low tan δ layer
Since the sulfur content of the high tan δ layer was made higher than the above sulfur content, tan δ of the high tan δ layer was set to a desired value,
It is advantageous to combine this with a low tan δ layer.

According to the invention of claim 7, in the power transmission belt according to claim 5 or 6, the low tan δ layer ACSM composition is AC.
1 to 7 parts by weight of N, N′-m-phenylene dimaleimide and 0.1 to 4.0 parts by weight of dipentamethylene thiuram tetrasulfide are blended with 100 parts by weight of SM, and the above high tan δ is obtained. Regarding the ACSM composition of the layer, 0.2 to 5.0 parts by weight of N, N'-m-phenylene dimaleimide and 0.1 to 4.0 parts by weight of dipentamethylene thiuram tetrasulfide are used with respect to 100 parts by weight of ACSM. Parts and pentaerythritol in an amount of 0.1 to 5.0 parts by weight, so that the tan δ of each of the low tan δ layer and the high tan δ layer can be controlled without causing insufficient vulcanization of rubber. This is advantageous in setting the desired value to improve sag resistance and crack resistance.

According to the invention of claim 8, the compression rubber layer of the transmission belt according to claim 7 has the above-mentioned ACS.
Since it is composed of a rubber material in which short fibers are mixed in the M composition, it is further advantageous in improving the sag resistance and crack resistance of the compressed rubber layer.

According to the inventions of claims 9 and 10, since the invention of claim 8 is applied to a V-belt or V-ribbed belt of a low edge type, the compression rubber layer has a sag and a crack. Occurrence can be prevented and the life of these belts can be extended.

[Brief description of the drawings]

FIG. 1 shows a V having a two-layered compressed rubber layer according to an embodiment.
Belt cross section

FIG. 2 shows a V having a two-layered compressed rubber layer according to an embodiment.
Ribbed belt cross section

FIG. 3 shows a V having a multilayered compressed rubber layer according to an embodiment.
Belt cross section

FIG. 4 shows a V having a compressed rubber layer having a multilayer structure according to an embodiment.
Ribbed belt cross section

FIG. 5 is a front view showing a mode of a running life test of a transmission belt.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 V-belt 3 core wire 4 Contact rubber layer 5 Two-layer compression rubber layer 5a Upper layer (low tan δ layer) 5b Lower layer (high tan δ layer) 6 Short fibers 7 V-ribbed belt 8 Two-layer compression rubber layer 8a Upper layer (Low tan δ layer) 8b Lower layer (high tan δ layer) 9 Rib 11 V belt 12 Multi-layered compressed rubber layer 12a Low tan δ layer 12b High tan δ layer 13 V ribbed belt 14 Multi-layered compressed rubber layer 14a Low tan δ Layer 14b High tan δ layer 15 Rib 20 Test belt 21 Drive pulley 22 Driven pulley 23 Idle pulley

Claims (10)

[Claims] 1. An adhesive rubber layer for holding a core wire extending in the longitudinal direction of the belt at an appropriate position and a compression rubber layer, wherein the compression rubber layer has a temperature of 100 ° C. and a frequency of 10 Hz.
A low tan formed by an alkylated chlorosulfonated polyethylene composition having a tan δ of 0.05 to 0.09.
Low tan δ at δ layer and temperature 100 ° C, frequency 10Hz
High tan δ formed by alkylated chlorosulfonated polyethylene composition higher than tan δ of tan δ layer
A power transmission belt, wherein layers are formed in a composite structure in which layers are layered in the belt thickness direction. 2. An adhesive rubber layer for holding a core wire extending in the longitudinal direction of the belt at an appropriate position and a compression rubber layer, wherein the compression rubber layer has a temperature of 100 ° C. and a frequency of 10 Hz.
A high tan formed by an alkylated chlorosulfonated polyethylene composition having a tan δ of 0.08 to 0.15.
High tan δ at δ layer and temperature 100 ° C, frequency 10Hz
Low tan δ formed by alkylated chlorosulfonated polyethylene composition lower than tan δ of tan δ layer
A power transmission belt, wherein layers are formed in a composite structure in which layers are layered in the belt thickness direction. 3. The transmission belt according to claim 1 or 2, wherein the compression rubber layer is formed in a two-layer structure of a low tan δ layer and a high tan δ layer, and has a low tan δ. A power transmission belt, wherein the layers are arranged on the side closer to the core and the high tan δ layers are arranged on the side farther from the core. 4. The transmission belt according to claim 1 or 2, wherein the compression rubber layer has a multi-layer structure in which low tan δ layers and high tan δ layers are alternately laminated. A power transmission belt characterized by that. 5. The power transmission belt according to claim 1, wherein the low tan δ layer has a sulfur content of 0.8 to 2.0 wt% in the alkylated chlorosulfonated polyethylene. %, And the sulfur content of the alkylated chlorosulfonated polyethylene of the high tan δ layer is lower than the sulfur content of the low tan δ layer. 6. The transmission belt according to claim 1, wherein the sulfur content of the alkylated chlorosulfonated polyethylene in the high tan δ layer is 0.5 to 0.8 weight. %, And the sulfur content of the alkylated chlorosulfonated polyethylene of the low tan δ layer is higher than the sulfur content of the high tan δ layer. 7. The power transmission belt according to claim 5, wherein the low tan δ layer of the alkylated chlorosulfonated polyethylene composition has an N content of 100 parts by weight of the alkylated chlorosulfonated polyethylene. , N′-m-phenylenedimaleimide in an amount of 1 to 7 parts by weight and dipentamethylene thiuram tetrasulfide in an amount of 0.1 to 4.0 parts by weight. The composition contains 0.2 to 5.0 parts by weight of N, N'-m-phenylenedimaleimide and 0.1 to 4 parts by weight of dipentamethylene thiuram tetrasulfide with respect to 100 parts by weight of alkylated chlorosulfonated polyethylene. A transmission belt comprising 0 parts by weight and 0.1 to 5.0 parts by weight of pentaerythrite. 8. The transmission belt according to claim 7, wherein short fibers are mixed in the compressed rubber layer. 9. The transmission belt according to claim 8 is a low edge type V belt. 10. The transmission belt according to claim 8 is a low edge type V-ribbed belt.