JP2003120756A - Power transmission belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission belt capable of reducing a belt slip ratio, reducing wear quantity, and reducing noise when the transmission belt runs. SOLUTION: This transmission belt comprises a V-ribbed belt 1 comprising an elastic material layer including an adhesive rubber layer 3 in which core wires 2 are embedded along length of the belt, and a compression rubber layer 4. For at least the compression rubber layer 4 of the elastic material layer comprising the adhesive layer 3 and the compression rubber layer 4, vulcanized matter of ethylene-α-olefine elastomer mix is used. Ethylene content in ethylene-α-olefine elastomer is 60-75 mass%. Total additive quantity of short fibers is 5-40 parts by weight to 100 parts by weight of ethylene-α-olefine elastomer. The short fibers comprise cotton and nylon.

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 specifically, it uses a specific ethylene-α-olefin elastomer in at least one of an adhesive rubber layer and a compression rubber layer to reduce the slip ratio of the belt. The present invention relates to a power transmission belt which has a small amount of wear and reduces noise when the belt is running.

[0002]

2. Description of the Related Art In recent years, the ambient temperature around the engine room of an automobile has risen as compared with the conventional temperature due to the social demand for energy saving and compactness. Along with this, the operating environment temperature of the power transmission belt has risen. Conventionally, natural rubber, styrene-butadiene rubber, and chloroprene rubber have been mainly used for power transmission belts, but in a high-temperature atmosphere, cracks occur in the compressed rubber layer that hardens early.

In order to prevent the belt from being damaged early,
Conventionally, improvement of heat resistance of chloroprene rubber has been studied,
Although some improvements have been made, there is a limit as long as chloroprene rubber is used, and at present no sufficient effect is obtained.

For this reason, the use of rubbers having a highly saturated or completely saturated main chain, such as chlorosulfonated polyethylene rubbers, hydrogenated nitrile rubbers, and fluororubbers, which are excellent in heat resistance, has been studied. . Of these, chlorosulfonated polyethylene is generally equivalent to chloroprene rubber in dynamic fatigue resistance, abrasion resistance, and oil resistance, but it is known that vulcanization system, particularly acid acceptor, has a great influence on water resistance. ing. Usually, oxides such as MgO and PbO have been used as acid acceptors for chlorosulfonated polyethylene.

However, PbO, Pb₃ O_Four Lead compounds such as
If you use the acid acceptor of
However, due to pollution and hygiene issues, the use of lead compounds is preferred.
No When MgO is used as an acid acceptor,
MgC formed during the crosslinking reaction _l2 Water resistance is remarkable due to
It was damaged and was not properly applied to the belt. Meanwhile, gold
Uses an epoxy acid acceptor as an acid acceptor other than metal oxides
If so, it is possible to obtain a composition having good water resistance.
However, there is a problem that an odor problem etc. occurs and makes the human body uncomfortable.
there were.

Further, this power transmission belt has a great improvement in belt running life in a high temperature atmosphere and excellent heat resistance as compared with a belt using chloroprene rubber, but in a low temperature atmosphere of -30 ° C. or lower. It was revealed that the belt running life under the belt was inferior. The reason for this is that the conventional chlorosulphonated polyethylene rubber is chlorosulphonated polyethylene, and since it contains chlorine, the cohesive energy of chlorine increases at low temperatures and the rubber cures at low temperatures. It is presumed that it lacks rubber elasticity and is easily broken.

For this reason, recently, it has been proposed to use an ethylene-α-olefin elastomer reinforced with a metal salt of an α-β-unsaturated organic acid instead of chloroprene rubber in a transmission belt, for example, Japanese Patent Laid-Open No. 4-339843. Bulletin,
Japanese Laid-Open Patent Publication No. 9-500930 and Japanese Patent Laid-Open No. 2000-266.
No. 74 and Japanese Patent Laid-Open No. 2000-283243. Further, Japanese Patent Publication No. 2001-500910 also discloses a power transmission belt using a blend of ethylene-α-olefin-vinyl norbornene elastomer.

The above ethylene-propylene rubber (EP
R) or ethylene-propylene-diene rubber (E
Ethylene-alpha-olefin elastomers such as PDM) have excellent heat resistance and cold resistance, and are attracting attention as relatively inexpensive and environmentally friendly polymers.

[0009]

However, when the ethylene content of the ethylene-propylene-diene rubber is high,
The sheeting processability deteriorates and holes are easily formed in the sheet during rolling, and when short fibers are added for the purpose of improving performance such as abrasion resistance, the sheet is more likely to have holes and breaks. was there. On the other hand, if the ethylene content is lowered in order to improve the sheeting property during rolling, there arises a problem that wear resistance is lowered.

Further, the transmission belt using the ethylene-propylene-diene rubber has a problem that the friction coefficient is low and slipping easily occurs. In particular, when the transmission belt of this type was run while pouring water, the friction coefficient was remarkably reduced.

The present invention addresses such a problem by reducing the slip ratio of the belt and reducing the amount of wear.
A power transmission belt that can reduce noise when the belt is running is provided.

[0012]

That is, in the invention of claim 1 of the present application, a power transmission belt including an adhesive rubber layer in which a core wire is embedded along the longitudinal direction of the belt, and an elastic layer including a compression rubber layer. A vulcanized product of an ethylene-α-olefin elastomer blend is used for at least a compression rubber layer of an elastic layer composed of an adhesive rubber layer and a compression rubber layer, and the ethylene content in the ethylene-α-olefin elastomer is 60%. ˜75% by mass, and the total amount of short fibers added is 5 to 40 parts by mass with respect to 100 parts by mass of ethylene-α-olefin elastomer, which is present in a power transmission belt in which cotton and nylon are added as short fibers. It is possible to reduce the slip ratio of the belt and the wear amount.

According to the invention of claim 2 of the present application, the power transmission belt contains 3 parts by mass or more of cotton.

In the invention of claim 3 of the present application, the power transmission belt is composed of an adhesive rubber in which a core wire is embedded along the longitudinal direction of the belt, and a compressed rubber layer having a plurality of rib portions extending in the circumferential direction of the belt. It is a ribbed belt.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The V-ribbed belt 1 shown in FIG.
A core wire 2 made of a high-strength and low-elongation cord made of a fibrous material is embedded in an adhesive rubber layer 3, and a compression rubber layer 4 which is an elastic layer is provided below the core wire 2. A plurality of ribs 7 having a substantially triangular cross section extending in the longitudinal direction of the belt are arranged on the compressed rubber layer 4, and a rubber-coated canvas 5 is provided on the back surface of the belt.
Is attached. Needless to say, the rubber-coated canvas 5 may not be provided on the back surface of the belt and the rubber layer may be exposed.

As another belt, a cut edge type V
There is a belt 21. As shown in FIG. 2, the belt 21 is composed of an adhesive rubber layer 24 in which a core wire 23 is embedded and a compressed rubber 26. Further, each surface layer of the adhesive rubber layer 24 and the compressed rubber layer 26 has a rubber-coated canvas 22. Are stacked.

The ethylene-α-olefin elastomer used in at least the compression rubber layer of the compression rubber layer and the adhesive rubber layer is a copolymer of ethylene and α-olefin (propylene, butene, hexene, or octene), or , A copolymer of ethylene, the α-olefin and a non-conjugated diene, and specifically a rubber composed of ethylene-propylene rubber (EPM) or ethylene-propylene-diene terpolymer (EPDM). Examples of the diene component include non-conjugated dienes having 5 to 15 carbon atoms such as ethylidene norbornene, dicyclopentadiene, 1,4-hexadiene, cyclooctadiene and methylene norbornene.

The ethylene content of the ethylene-α-olefin elastomer is 60 to 75% by mass.
If the ethylene content exceeds 75% by mass, the crystallinity will rapidly increase and the low temperature characteristics will deteriorate, and the workability of sheeting when short fibers will be added will deteriorate, and holes will easily form in the sheet during rolling, It becomes easy to tear. On the other hand, when the content is less than 60% by mass, aggregation of the elastomer is improved due to the characteristics of propylene which is an α-olefin, and even if a large amount of short fibers is added, the sheet is less likely to have holes during rolling, and sheeting is easy, The mechanical strength decreases and the belt wear resistance deteriorates.

The content of diene in the ethylene-α-olefin elastomer is 0.1 to 3.5% by mass, preferably 0.1 to 3.0% by mass, and when it is less than 0.1% by mass,
As the belt runs, the rubber softens and deteriorates, making it easier to produce sound. On the other hand, when it exceeds 3.5% by mass, the diene component largely contributes to the hindrance of bending of the ethylene-propylene chain which is the polymer main chain, and cracks are likely to occur in the compressed rubber layer during belt bending running.

In the present invention, ethylene-α-olefin elastomers having different diene contents may be blended, and the number of polymers to be blended is not limited.
The total diene content should satisfy the above range. Further, the blending may be performed between an ethylene-propylene-diene terpolymer containing a diene component and an ethylene-propylene copolymer containing no diene component.

In the ethylene-propylene-diene terpolymer, a diene component having a double bond is introduced into the molecule as a crosslinking site for sulfur vulcanization. However, if the diene content is small, the crosslinking density becomes small, and therefore it is commercially available. In many products, the diene content exceeds 3.5% by mass. Even in the case of peroxide vulcanization, when the diene content is low, the crosslink density is low and adhesive wear is likely to occur.

As the peroxide co-crosslinking agent, N,
N'-m-phenylenedimaleimide can be added. The addition amount of N, N′-m-phenylenedimaleimide is 0.2 to 10 parts by mass with respect to 100 parts by mass of the ethylene-α-olefin elastomer, and when less than 0.2 parts by mass, the crosslinking density is If the amount exceeds 10 parts by mass, the elongation of the vulcanized rubber is remarkably reduced and the bending resistance becomes a problem.

Further, by adding 0.01 to 1 part by mass of sulfur to 100 parts by mass of the ethylene-α-olefin elastomer, it is possible to control the decrease in elongation of the vulcanized rubber. If it exceeds 1 part by mass, the physical properties are deteriorated, the abrasion property during belt running is large, and the adhesive abrasion property is generated.

The organic peroxide is usually rubber,
Diacyl peroxide used for resin crosslinking,
Peroxyester, diallyl peroxide, di-t
-Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2.5-dimethyl-2
-5-di (t-butylperoxy) -hexane-3,1
-3-bis (t-butylperoxy-isopropyl) benzene, 1.1-di-butylperoxy-3,3,5-
Trimethylcyclohexane and the like are preferable, and the one-minute half-life by thermal decomposition of 150 to 250 ° C. is preferable. The amount added is 100 ethylene-α-olefin elastomers.
It is about 1 to 8 parts by weight, preferably 1.
5 to 4 parts by mass.

Further, the compression rubber layer is mixed with short fibers made of nylon 6 and nylon 66 such as nylon and cotton to improve the lateral pressure resistance of the compression rubber layer, and at the same time the compression rubber layer to be the surface in contact with the pulley. The surface of the short fiber is polished by a grinder to expose the short fiber. The coefficient of friction of the surface of the compressed rubber layer is reduced, which has the effect of reducing noise when the belt is running.

In order for the above-mentioned short fibers to sufficiently exert the above-mentioned effects, the total amount of the short fibers added is 5 to 40 parts by mass, and it is necessary to add 3 parts by mass or more of cotton. More preferably, the cotton is 3 to 10 parts by mass and the nylon is 2 to 30 parts by mass. If the total amount of the short fibers added is less than 5 parts by mass, sufficient reinforcing properties as a blend cannot be obtained, and there arises a problem that abrasion resistance when used as a belt is insufficient. On the other hand, when the amount exceeds 40 parts by mass, it becomes difficult to knead into rubber and the dispersion of fibers becomes poor.

Further, in the compressed rubber layer, if necessary, a reinforcing agent such as carbon black or silica, a filler such as clay or calcium carbonate, a softening agent, a processing aid, an antiaging agent,
Various agents such as a co-crosslinking agent such as TAIC may be added.

Further, nitrile rubber, hydrogenated nitrile rubber, hydrogenated nitrile rubber to which an unsaturated carboxylic acid metal salt is added together with ethylene-α-olefin elastomer, chlorosulfonated polyethylene, chloroprene,
Urethane rubber, epichlorohydrin rubber, natural rubber, C
It is also possible to blend SM, ACSM, SBR.

A cord made of polyethylene terephthalate fiber, polyester fiber having ethylene-2,6-naphthalate as a main constituent unit, and polyamide fiber is used for the core wire, and adhesion treatment is carried out for the purpose of improving the adhesiveness with the rubber composition. Is applied. As such an adhesion treatment, it is general that the fibers are immersed in resorcin-formalin-latex (RFL solution) and then dried by heating to form a uniform adhesive layer on the surface. However, without being limited to this, after pretreatment with an epoxy or isocyanate compound, R
There is also a method of treating with FL solution.

The ethylene-2,6-naphthalate used in the present invention is usually polycondensed with naphthalene-2,6-dicarboxylic acid or an ester-forming derivative thereof in the presence of a catalyst under suitable conditions with ethylene glycol. To synthesize. At this time, a copolymer polyester is synthesized by adding one or more appropriate third components before the completion of the polymerization of ethylene-2,6-naphthalate.

In the adhesion treatment of the above-mentioned core wire, first, (1) an untreated cord is impregnated in a tank containing a treatment liquid selected from an epoxy compound or an isocyanate compound and pre-dipped, and then (2) 160 to 200 ° C. It is dried by passing it through a drying oven whose temperature is set to 30 to 600 seconds, and (3) subsequently, it is immersed in a tank containing an adhesive solution consisting of an RFL solution, and (4) 210.
-30 to a stretching heat-fixing machine whose temperature is set to 260-C
It is stretched by -1 to 3% for 600 seconds to obtain a stretch-treated cord.

The RFL liquid is a mixture of latex with an initial condensate of resorcin and formalin. As the latex used here, chloroprene, styrene / butadiene / vinyl pyridine terpolymer, hydrogenated nitrile, NBR, etc. Is.

The cover canvas is a cloth woven into a plain weave, a twill weave, a satin weave, etc., using a thread made of cotton, polyamide, polyethylene terephthalate, and aramid fiber. Of course,
The cover canvas may not be used.

The rubber composition of the compressed rubber layer contains
Carbon black, a plasticizer, an antiaging agent, and a processing aid that are commonly used can be added. The method of mixing the respective components is not particularly limited, and for example, a Banbury mixer, a kneader or the like can be used and the kneading can be appropriately performed by a known means and method.

An example of the method for manufacturing the V-ribbed belt is as follows. First, 1 on the peripheral surface of the cylindrical forming drum.
~ After wrapping a plurality of cover canvas and adhesive rubber layer,
Spin a cord consisting of a cord on top of this,
Further, the compressed rubber layer is sequentially wound to obtain a laminated body, which is then vulcanized to obtain a sleeve.

Next, the sleeve is hung on a driving roll and a driven roll to run under a predetermined tension, and the further rotating grinding wheel is moved so as to come into contact with the running vulcanization sleeve, and the compression rubber of the sleeve is moved. Grind 3 to 100 grooves on the surface of the layer at once. The sleeve thus obtained is removed from the driving roll and the driven roll, the sleeve is hung on the other driving roll and the driven roll to run, and cut into a predetermined width by a cutter to finish each V-ribbed belt. .

[0037]

EXAMPLES The present invention will now be described in more detail with reference to examples. Examples 1 to 2 and Comparative Examples 1 to 4 In the V-ribbed belts produced in the present examples, the core wire made of polyester fiber cord is embedded in the adhesive rubber layer, and two plies of rubber-coated cotton canvas are laminated on the upper side thereof. On the other hand, three ribs are arranged in the belt longitudinal direction on the compression rubber layer provided below the adhesive rubber layer.

A compressed rubber layer was prepared from the rubber composition shown in Table 1, kneaded with a Banbury mixer, and then rolled with a calender roll. The compressed rubber layer contains short fibers and is oriented in the belt width direction. The adhesive rubber layer has a rubber composition obtained by removing short fibers from the rubber composition shown in Table 1.

[0039]

[Table 1]

The belt is manufactured by a conventional method. First, a two-ply rubber-coated cotton canvas cloth is wound around a flat cylindrical mold, and then an adhesive rubber layer is wound around the core wire to spin the core wire to install a compressed rubber layer. After that, the vulcanization jacket is inserted on the compressed rubber layer. Then, the molding mold is placed in a vulcanization can, and after vulcanization, the tubular vulcanization sleeve is taken out of the mold, the compression rubber layer of the sleeve is molded into ribs by a grinder, and the molded body is cut into individual belts. The process consists of

The V-ribbed belt thus obtained was 3 PK1,000, and Table 2 shows the test results of the slip ratio of this belt during water-filling running and running during dry running.

In the water injection running test, the V-ribbed belt was driven by a driving pulley (diameter 80 mm) and a driven pulley (diameter 110 mm).
mm) and adjust the belt tension to 15 kgf,
At the ambient temperature of 23 ° C, the driven pulley was driven at a torque of 3 kg / m, the rotation speed of the driving pulley was 2,000 rpm, and further, it was run under anhydrous and water injection (water injection amount 120 ml / min) conditions. It was calculated from the ratio of the rotational speed of the driven pulley.

In a wear test at a 6% slip ratio, a 3-ribbed V-ribbed belt was used as a three-axis pulley consisting of a drive pulley (diameter 80 mm), a driven pulley (diameter 80 mm) and an idler pulley (diameter 120 mm) at room temperature. Suspended, torque 0.7kg · m on driven pulley, ambient temperature 23 ° C, rotation speed of drive pulley 3,000rpm, 6%
The amount of adhesive wear on the surface of the belt after running for 24 hours at the slip ratio of was measured. The amount of wear (%) is a value obtained by dividing the belt weight difference before and after running by the belt weight before running.

[0044]

[Table 2]

As is clear from the results of the running test shown in Table 2, Examples 1 and 2 are different from each other due to the combined use effect of cotton and nylon.
The slip ratio at the time of water injection and dry was small, and the wear amount was also small in the wear test. On the other hand, in Comparative Example 1, meta-aramid increases slippage during water injection. In Comparative Example 2, the slip was suppressed by the presence of cotton, but the abrasion resistance was not sufficient. In Comparative Examples 3 and 4, the presence of cotton and para-aramid suppresses some slip, but it is not sufficient. In Comparative Example 5, it can be seen that the amount of short fibers is too large and the slip is large.

[0046]

As described above, according to the invention of the claims of the present application,
A vulcanized product of an ethylene-α-olefin elastomer compound is used for at least a compression rubber layer of an elastic layer composed of an adhesive rubber layer and a compression rubber layer, and the ethylene content in the ethylene-α-olefin elastomer is 60 to 75. Mass% and ethylene-α-olefin elastomer 10
The total amount of short fibers added to 0 parts by mass is 5 to 40 parts by mass, and it is in a power transmission belt in which cotton and nylon are added as short fibers to reduce the slip ratio of the belt and reduce the wear amount. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a V-ribbed belt according to the present invention.

FIG. 2 is a vertical sectional view of a V-cut edge type V-belt according to the present invention.

[Explanation of symbols]

1 V ribbed belt 2,23 core wire 3,24 Adhesive rubber layer 4,26 Compressed rubber layer 5,22 rubber canvas 7 Rib 21 V belt

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 77/00 C08L 77/00 F16G 5/20 F16G 5/20 A (72) Inventor Toshimichi Takada Kobe City 4-1-21, Hamazoe-dori, Nagata-ku 3F Star Belt Co., Ltd. F-term (reference) 4F072 AA02 AA08 AA09 AB03 AB06 AB33 AD02 AL09 4J002 AB012 BB151 CL012 CL032 FA042 GM01

Claims (3)

[Claims] 1. A power transmission belt comprising an adhesive rubber layer having a core wire embedded along the longitudinal direction of the belt and an elastic body layer including a compression rubber layer, wherein an elastic body layer comprising the adhesive rubber layer and the compression rubber layer is provided. A vulcanized product of an ethylene-α-olefin elastomer blend is used for at least the compressed rubber layer, the ethylene content in the ethylene-α-olefin elastomer is 60 to 75% by mass, and the ethylene-α-olefin elastomer is 10%.
A power transmission belt, wherein the total amount of the short fibers added is 0 to 40 parts by weight, and cotton and nylon are added as the short fibers. 2. The power transmission belt according to claim 1, wherein the cotton contains 3 parts by mass or more. 3. The V-ribbed belt, wherein the power transmission belt is a V-ribbed belt including an adhesive rubber having a core wire embedded along a longitudinal direction of the belt and a compression rubber layer having a plurality of rib portions extending in a circumferential direction of the belt. The belt for power transmission described in 2.