JP3403938B2 - Rubber composition and power transmission belt using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a transmission belt ,
In detail, the belt running life under high temperature atmosphere and low temperature atmosphere is remarkably improved, and the V-ribbed sleeve has excellent wear resistance.
A transmission belt relating to the belt.

[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 also risen. Conventionally, natural rubber, styrene-butadiene rubber, and chloroprene rubber have been mainly used for power transmission belts, but in a high temperature atmosphere, a problem occurs that cracks occur early in the cured compressed rubber layer.

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 are limits as long as chloroprene rubber is used, and at present, sufficient effects have not been 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, when an acid acceptor of a lead compound such as PbO or Pb ₃ O ₄ is used, a belt having good water resistance can be obtained, but use of the lead compound is not preferable due to pollution and hygiene problems. When MgO is used as an acid acceptor,
Water resistance is significantly impaired by MgC _l2 formed during the crosslinking reaction, adaptation to the belt it was inadequate. On the other hand, if an epoxy acid acceptor is used as an acid acceptor other than the metal oxide, it is possible to obtain a composition having good water resistance, but it causes odor problems and the like and causes discomfort to the human body. There was a problem to give.

However, 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 at a temperature of -30 ° C or lower. It was revealed that the running life of the belt in a low temperature atmosphere was extremely poor. 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.

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. It is disclosed in Japanese Patent Publication No. 500930.

[0008]

On the other hand, ethylene-α-olefin elastomers such as ethylene-propylene-diene rubber (EPDM) are superior in heat resistance and cold resistance to chloroprene rubber, There is a problem in that the abrasion resistance is poor, and in particular, the abrasion powder generated due to the abrasion with the pulley during running of the belt adheres to the surface of the belt and tends to produce sound during running.

On the other hand, ethylene-α-using a sulfur vulcanization system
Olefin elastomers are difficult to sufficiently increase the degree of cross-linking, and are highly worn during running. Especially, in V-ribbed belts, abrasion powder is likely to be accumulated at the bottom of the rib crests, resulting in adhesive wear. Further, when an ethylene-α-olefin elastomer having an extremely large amount of double bonds in the molecule is used to increase the degree of crosslinking, adhesive wear can be improved to some extent, but there is a problem that heat resistance is reduced.

The present invention addresses such a problem, and is a V-ribbed belt having excellent heat resistance and cold resistance, improved adhesion wear resistance, and improved belt durability. The purpose is to provide such a power transmission belt.

[0011]

That is, according to the invention of claim 1 of the present application, the bonding in which the core wire is embedded along the longitudinal direction of the belt.
Rubber and pressure that has multiple ribs that extend in the circumferential direction of the belt.
For a transmission belt consisting of a V-ribbed belt with a curly rubber layer
At least in the rib portion, ethylene-α-olefin
N, N'-m-fl
Add 0.2 to 10 parts by weight of ethylene dimaleimide,
-For power transmission belts that use an oxide-vulcanized rubber layer
It

According to the second aspect of the present invention, ethylene-α
-Sulfur is added to 100 parts by weight of the olefin elastomer.
0.01 to 1.0 part by weight is added to the transmission belt .

[0013]

[0014]

[0015]

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The V-ribbed belt 1 shown in FIG.
A core wire 2 made of a high-strength, low-elongation cord made of polyester fiber, aramid fiber, or glass fiber is embedded in an adhesive rubber layer 3, and a compression rubber layer 4 as an elastic layer is provided below the core wire 2. is doing. The compressed rubber layer 4 is provided with a plurality of ribs 7 having a substantially triangular cross section extending in the longitudinal direction of the belt, and a rubber-attached canvas 5 attached to the surface of the belt.

[0017]

Ethylene used in the compressed rubber layer 4
The α-olefin elastomer refers to a rubber made of ethylene-propylene rubber (EPR) or ethylene-propylene-diene monomer (EPDM). Examples of the diene monomer include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, cyclooctadiene and the like.

To the compressed rubber layer 4 , peroxide is added as a vulcanizing agent for ethylene-α-olefin elastomer, and N, N'-m-phenylene dimaleimide is added as a co-crosslinking agent. The amount of N, N′-m-phenylenedimaleimide added is 0.2 to 10 parts by weight with respect to 100 parts by weight of the ethylene-α-olefin elastomer.
If it is less than 0.2 parts by weight, the crosslink density will be small and the effect of improving wear resistance and adhesive wear resistance will be small. Causes a problem.

Further, the addition of 0.01 to 1 part by weight of sulfur to 100 parts by weight of the ethylene-α-olefin elastomer makes it possible to control the decrease in the elongation of the vulcanized rubber. If it exceeds 1 part by weight, the degree of crosslinking does not improve to the extent that it can be expected, so that the vulcanized rubber also does not improve in unwear resistance and tack wear resistance.

The above-mentioned 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 one having a half-life of 1 minute by thermal decomposition of 150 to 250 ° C is preferable. The addition amount is ethylene-α-olefin elastomer 10
It is about 1 to 8 parts by weight, preferably 1.5 to 4 parts by weight, relative to 0 parts by weight.

Further, the compression rubber layer 4 is mixed with short fibers made of nylon 6, nylon 66, polyester, cotton, and aramid to improve the lateral pressure resistance of the compression rubber layer 4 and to be a surface in contact with the pulley. The surface of the compressed rubber layer 4 is ground by a grinder to project the short fibers. The coefficient of friction of the surface of the compressed rubber layer 4 is reduced to reduce noise when the belt is running. Among these short fibers, aramid short fibers that are rigid, have strength, and have abrasion resistance are most effective.

In order for the short aramid fibers to sufficiently exhibit the above-mentioned effects, the fiber length of the aramid fibers is 1 to 20.
The addition amount is 1 to 30 parts by weight with respect to 100 parts by weight of the ethylene-α-olefin elastomer. This aramid fiber is an aramid having an aromatic ring in its molecular structure,
For example, product names Conex, Nonex, Kevlar,
Technora, Twaron, etc.

In the compressed rubber layer 4 , the ethylene-α-olefin elastomer and the fiber diameter are 1.0 μm or less, preferably 0.05 to 0, based on 100 parts by weight of the ethylene-α-olefin elastomer which is the matrix rubber. .8
1 to 50 parts by weight, preferably 5 to 25 parts by weight, of the fiber component may be contained in the micro short fiber reinforced rubber graft-bonded with the micro short fibers of μm. If the amount of the fine short fiber reinforced rubber is less than 1 part by weight, the abrasion resistance is not sufficient, and if it exceeds 50 parts by weight, the elongation of the rubber composition is lowered, and the heat resistance and the bending resistance are lowered.

This fine short fiber reinforced rubber is a matrix because the ethylene-α-olefin elastomer constituting it is completely the same or similar to the ethylene-α-olefin elastomer of the matrix rubber of the compression rubber layer 4. Bonds well with rubber. Therefore, since the ethylene-α-olefin elastomer and the minute short fibers are chemically bonded between the minute short fiber reinforced rubber and the matrix rubber, or even in the minute short fiber reinforced rubber, the compressed rubber layer 4
Is hard to crack, and even if a crack occurs, it is difficult to propagate.

In the fine short fiber reinforced rubber, the interface between the fine short fibers and the ethylene-α-olefin elastomer is a coupling agent such as vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, γ.
A silane coupling agent such as methacryloxypropyltrimethoxysilane, a titanate coupling agent such as isopropyltriisostearoyl titanate,
It is grafted via an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid or the like or an adhesive such as a novolac type phenolic resin.
It is obtained by kneading and extruding an α-olefin elastomer, fine short fibers, and an adhesive such as a coupling agent at a temperature above the temperature at which the short fibers melt.

In this fine short fiber reinforced rubber, a rubber component is used as a continuous phase, in which fine short fibers are dispersed in a fine form, and the fine short fibers form a strong chemical bond or interact with the rubber component at the interface. ing. Therefore, the rubber layer containing the same is unlikely to be cracked, and even if cracked, it is difficult to propagate. Moreover, the belt using this is also excellent in heat resistance, cold resistance, bending resistance and abrasion resistance.

Further, in the compressed rubber layer 4 , if necessary, a reinforcing agent such as carbon black and silica, a filler such as clay and calcium carbonate, a softening agent, a processing aid, an antiaging agent, and co-crosslinking such as TAIC. Various agents such as agents may be added.

The compressed rubber layer 4 is made of ethylene-
Nitrile rubber, hydrogenated nitrile rubber, hydrogenated nitrile rubber with unsaturated carboxylic acid metal salt added, α-olefin elastomer, chlorosulfonated polyethylene, chloroprene, urethane rubber, epichlorohydrin rubber, natural rubber, CSM, ACSM, SBR Is used.

The hydrogenated nitrile rubber has a hydrogenation rate of 80% or more and exhibits heat resistance and ozone resistance.
90% or more is preferable. A hydrogenated nitrile rubber having a hydrogenation rate of less than 80% has extremely low heat resistance and ozone resistance. Considering oil resistance and cold resistance, the bound acrylonitrile amount is preferably in the range of 20 to 45%.

Chlorosulfonated polyethylene has a chlorine content of 15 to 35% by weight, preferably 25 to 32% by weight.
And a linear low-density polyethylene chlorosulfonated so that the sulfur content is in the range of 0.5 to 2.5% by weight.

An ethylene-α-olefin elastomer composition similar to that used for the compression rubber layer 4 is also used for the adhesive rubber layer 3 . However, in order to bond well with polyester fibers, aromatic polyamide fibers, glass fibers, etc., which are core wires, peroxide-free sulfur-vulcanized ethylene-α-olefin elastomer compositions and chlorosulfonated polyethylene compositions Alternatively, a hydrogenated nitrile rubber composition can be used.

A rope made of polyethylene terephthalate fiber, polyester fiber containing ethylene-2,6-naphthalate as a main constituent unit, and polyamide fiber is used for the core wire 2 , and the adhesive treatment is performed for the purpose of improving adhesiveness with rubber. Is given. 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, the method is not limited to this, and after pretreatment with an epoxy or isocyanate compound, the RFL
There is also a method of treating with a liquid.

The ethylene-2,6-naphthalate used in the present invention is usually polycondensed with naphthalene-2,6-dicarboxylic acid or its ester-forming derivative with ethylene glycol in the presence of a catalyst under appropriate conditions. 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 and an isocyanate compound to pre-dip, and (2) 160 to 200 °. It is dried by passing it through a drying oven whose temperature is set to C for 30 to 600 seconds, and (3) then RFL.
Immerse it in the tank containing the adhesive solution (4) 21
30 for a stretching heat-fixing machine whose temperature is set to 0 to 260 ° C.
It is stretched by -1 to 3% for about 600 seconds to obtain a stretched cord.

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

The cover canvas 5 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.

A compressed rubber layer used for the belt 1
Carbon rubber, a plasticizer, an antiaging agent, and a processing aid that are commonly used can be added to the rubber composition of No. 4 . 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 of manufacturing the V-ribbed belt 1 is as follows. First, 1 to the peripheral surface of the cylindrical forming drum
After wrapping a plurality of cover canvas and cushion rubber layer, a core wire made of rope is spirally spun on this, and a compressed rubber layer is further wound in sequence to obtain a laminate,
This is vulcanized to obtain a vulcanized sleeve. Next, the vulcanization sleeve is hung on the driving roll and the driven roll to run under a predetermined tension, and the further rotated grinding wheel is moved so as to come into contact with the running vulcanization sleeve to compress the vulcanization sleeve. A plurality of groove-shaped portions of 3 to 100 are ground at once on the surface of the rubber layer. The vulcanized sleeve thus obtained is removed from the drive roll and the driven roll, the vulcanized sleeve is hung on the other drive roll and the driven roll to run, and is cut into a predetermined width by a cutter, Finish with a V-ribbed belt.

[0040]

EXAMPLES The present invention will now be described in more detail with reference to examples. Examples 1 to 8 and Comparative Examples 1 to 6 In the V-ribbed belts manufactured in the present examples, the core wire made of polyester fiber rope is embedded in the adhesive rubber layer,
Two plies of rubber-coated cotton canvas are laminated on the upper side thereof, while a compression rubber layer is formed on the lower side of the adhesive rubber layer, and three ribs are provided in the belt longitudinal direction. The obtained V-ribbed belt is R
A K type 3-ribbed belt with a length of 975 mm according to the MA standard, a rib pitch of 3.56 mm, a rib height of 2.9 mm,
The belt thickness is 5.3 mm and the rib angle is 40 °.

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.

[0042]

[Table 1]

The belt manufacturing method is 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 results of the adhesive wear test, the heat resistance running test and the cold resistance running test of the V-ribbed belt thus obtained are shown in Table 1.

In the adhesive wear test, the V-ribbed belt was driven at room temperature to have a driving pulley (diameter 120 mm), a driven pulley (diameter 120 mm) and an idler pulley (diameter 45 m).
m), the driven pulley has a load of 12 horsepower, the idler pulley has a mounting load of 85 kgf, and the rotation speed is 4900 and is 48.
The presence or absence of adhesive wear on the surface of the belt after running for hours was examined.

The running tester used for the evaluation of the heat resistance running test was a driving pulley (diameter 120 mm), a driven pulley (diameter 120 mm), and an idler pulley (diameter 45 m).
m) and a tension pulley (diameter 70 mm) are combined and arranged. A belt was hung on each pulley of the tester, the ambient temperature was 120 ° C, and the rotation speed of the drive pulley was 49.
At a speed of 00 rpm and a driven pulley load of 12 horsepower, the tension pulley was driven with an initial tension of 57 kgf. Also, the idler pulley engages on the back surface of the V-ribbed belt and its wrap angle is about 120 degrees. By this running test method, the time until cracks were generated in the rib portion of the belt was measured, and the heat resistance performance was compared.

Furthermore, the evaluation method of the cold running test is as follows: drive pulley (diameter 140 mm) and driven pulley (diameter 45 mm).
And hung the belt to the rear idler pulley (diameter 75 mm) and, applying a load of 85kgf the driven pulley, -40
After being left for 18 hours at 700 rpm in an atmosphere of ° C, it was run for 1 minute, then stopped for 2 minutes, and this was repeated to measure the time until the belt cracked.

As is clear from the results of the running test in Table 1, the belt of this example using the rubber composition of ethylene-propylene rubber as the rib portion did not cause adhesive wear as compared with the conventional belt, and It can be seen that the belt life is improved in a high temperature atmosphere and a low temperature atmosphere as compared with a belt using chloroprene rubber, and it has excellent heat resistance and cold resistance.

Comparative Example 7 A compression rubber layer was prepared using the CR rubber compound shown in Table 2,
The mixture was kneaded with a Banbury mixer and then rolled with a calendar roll. The compressed rubber layer contains short fibers and is oriented in the belt width direction. As the adhesive rubber layer, a rubber compound excluding nylon cut yarn and aramid cut yarn was used in the compound of the compressed rubber layer. Table 2 shows the results of the adhesive wear test, the heat resistance running test and the cold resistance running test of the V-ribbed belt thus obtained.

[0050]

[Table 2]

As a result, it can be seen that the belt using the CR rubber compound has no adhesive wear, but is inferior in heat resistance and cold resistance as compared with the examples.

[0052]

As described above, according to the invention of the claims of the present application,
Adhesive rubber with cores embedded along the belt lengthwise direction
A compressed rubber layer with multiple ribs extending in the circumferential direction
The transmission belt consisting of the V-ribbed belt has
Even if there is no rib, ethylene-α-olefin elast
N, N'-m-phenylene diene based on 100 parts by weight of mar
Add 0.2 to 10 parts by weight of maleimide,
It is in a transmission belt that uses a rubber layer that has been vulcanized.
Improves adhesive wear resistance, heat resistance, and cold resistance of the belt
It has the effect of improving durability .

[Brief description of drawings]

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

[Explanation of Codes] 1 V-ribbed belt 2 Core wire 3 Adhesive rubber layer 4 Compressed rubber layer 5 Canvas with rubber 7 Rib section

Claims (2)

(57) [Claims] 1. A core wire is embedded along the longitudinal direction of the belt.
Also includes adhesive rubber and multiple ribs that extend in the circumferential direction of the belt.
V-ribbed belt with two compressed rubber layers
At least in the rib portion, ethylene-α-ole
N, N'-m based on 100 parts by weight of fin elastomer
-Adding 0.2 to 10 parts by weight of phenylene dimaleimide.
However, a special feature is that a peroxide-vulcanized rubber layer is used.
A transmission belt to collect . 2. An ethylene-α-olefin elastomer
Add 0.01 to 1.0 parts by weight of sulfur to 100 parts by weight.
The transmission belt according to claim 1, which is added .