JPH05346140A - Toothed belt - Google Patents

Abstract

PURPOSE:To improve durability and water proof and reduce traveling noise level by improving the back rubber layer and the matrix of the toothed rubber layer on one side of the back rubber layer respectively, and executing an appropriate treatment to the core wires embedded in the back rubber layer and the tooth cloth adhered on the toothed rubber layer respectively. CONSTITUTION:A toothed belt (A) consists of a back rubber layer 1 where a plurality of cores are embedded, a plurality of toothed rubber layers 3 which are integrally formed on one side of the back rubber layer 1, and a tooth cloth 4 which is integrally adhered to the tooth surface of the toothed rubber layer 3. In this case, the back rubber layer 1 and the tooth rubber layer 3 are formed of the respectively specified peroxide cross-linked hydro-nitrile rubber composition. The cores 2 are formed of glass fibers, and successively treated by using two kinds of liquids having different specific compositions. The tooth cloth 4 is covered by resorcinol/formalin/latex compositions containing natural rubber and isoprene in the latex component. This arrangement allows the improvement of the durability and water proof and the reduction of the traveling noise level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothed belt, and more particularly to a toothed belt excellent in durability and water resistance.

[0002]

2. Description of the Related Art Toothed belts have a back rubber layer in which a plurality of core wires are embedded, a plurality of tooth rubber layers formed on one side of the back rubber layer, and an adhesive to the tooth surface of the tooth rubber layer. It is made of tooth cloth. The back rubber layer and the tooth rubber layer are generally composed of chloroprene rubber, but recently, for example, in order to cope with higher engine output, chlorosulfonated polyethylene having better heat resistance than chloroprene rubber. Some are composed of rubber or sulfur-based hydrogenated nitrile rubber (JP-A-60-121341 and JP-A-60-41341).
-172749).

The core wire is generally made of glass fiber, but when it is repeatedly subjected to bending stress, it peels off from the matrix of the back rubber layer and the belt performance is deteriorated.
Therefore, recently, by applying resorcin-formalin-latex (RFL) treatment to the core wire, the familiarity and the adhesive force between the core wire and the matrix are increased to prevent the separation of the both.

The tooth cloth is formed by weaving nylon fibers or aramid fibers, for example, and is generally coated with a rubber paste in order to increase the adhesive strength with the tooth rubber layer.

[0005]

However, even if the back rubber layer and the tooth rubber layer are made of chlorosulfonated polyethylene rubber or the like having excellent heat resistance as described above, there is a tendency that the output of the engine is increased. In view of this, it is desirable to further sufficiently enhance the heat resistance of the back rubber layer and the tooth rubber layer.

Further, although the core wire described above can be prevented from being separated from the matrix by RFL treatment, it cannot be said that the water resistance is sufficient.

Further, although the above-mentioned tooth cloth increases the adhesive strength with the tooth rubber layer by the rubber paste treatment, it cannot be said that the water resistance is sufficient.

The present invention has been made in view of the above points, and an object of the present invention is to improve the matrix of the back rubber layer and the tooth rubber layer, and to appropriately treat the cord and the tooth cloth. Improves durability and water resistance,
Furthermore, it is intended to reduce noise when the belt is running.

[0009]

In order to achieve the above object, the present invention provides a back rubber layer in which a plurality of core wires are embedded,
The following means for solving the problems was taken for a toothed belt composed of a plurality of tooth rubber layers formed on one surface of the back rubber layer and a tooth cloth bonded to the tooth surface of the tooth rubber layer.

That is, the first solution of the present invention is to use 100 g of hydrogenated nitrile rubber for the back rubber layer and the tooth rubber layer.
Per 0.002 to 0.03 mol of peroxide and 1 to 7 g of a terminal carboxylated liquid 1,2-polybutadiene having a molecular weight of 500 to 5000 as a co-crosslinking agent. Further, a first liquid in which the core wire is made of glass fiber, contains resorcin / formaldehyde initial condensate, vinylpyridine-styrene-butadiene and chlorosulfonated polyethylene as main components, and natural rubber or isoprene rubber is added. Treated and further nitrile rubber and /
Alternatively, it is treated with a second liquid containing hydrogenated nitrile rubber, isocyanate and chlorinated rubber. Further, the above-mentioned tooth cloth is characterized in that a latex component is coated with a resorcin-formalin latex composition containing at least natural rubber or isoprene rubber.

A second solving means of the present invention is characterized in that, in the first solving means, the glass fiber constituting the core wire has a high-strength glass composition.

[0012]

With the above structure, in the first solution of the present invention, the back rubber layer is formed by the 1,2-polybutadiene contained in the peroxide-crosslinked hydrogenated nitrile rubber composition constituting the back rubber layer and the tooth rubber layer. The durability of the tooth rubber layer is further improved. Further, the natural rubber or isoprene rubber in the first liquid, which is the treatment liquid for the cord, suppresses the curing, and the natural rubber or isoprene rubber adheres well to the glass filament, thereby improving the water resistance of the cord. Further, the natural rubber or isoprene rubber in the latex component that coats the tooth cloth suppresses curing and makes it difficult to crack, and the natural rubber or isoprene rubber adheres well to the glass filament to improve the water resistance of the tooth cloth. In addition, the NCO on the surface of the cord and the surface of the tooth cloth react with the carboxylic acid of the tooth rubber layer to improve the adhesive force of the three members, and the belt hardening due to heat aging is suppressed, and the noise during belt running is reduced. ..

In the second solution of the present invention, high strength is imparted to the toothed belt due to the high strength glass composition of the glass fibers forming the core wire.

[0014]

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

FIG. 1 shows a toothed belt A according to an embodiment of the present invention.
1 is a back rubber layer in which a plurality of core wires 2, 2, ... Are embedded, and a plurality of tooth rubber layers 3, 3, ... Are integrally formed on one surface of the back rubber layer 1. The tooth cloth 4 is integrally bonded to the tooth surfaces of the tooth rubber layers 3, 3, ....

The back rubber layer 1 and the tooth rubber layer 3 are composed of 0.002 peroxide per 100 g of hydrogenated nitrile rubber.
~ 0.03 mol and molecular weight of 500 to 50 as co-crosslinking agent
It is composed of a peroxide-crosslinked hydrogenated nitrile rubber composition containing 1 to 7 g of a terminal carboxylated liquid 1,2-polybutadiene of No. 00.

Hydrogenated nitrile rubber prevents deterioration of rubber elasticity due to sulfur recombination reaction by hydrogenating the double bond contained in nitrile rubber to make it difficult for sulfur recombination reaction to occur in heat aging. Thus, the rubber has improved heat resistance while maintaining oil resistance, which is an advantage of nitrile rubber. In the present invention, the hydrogenation rate is 80
% Or more, especially, the hydrogenation rate is 95% or more, especially 98
% Or more of highly hydrogenated nitrile rubber is preferably used. When the hydrogenation rate is less than 80%, the resulting toothed belt A is still inferior in heat resistance.

The peroxide crosslinking agent is not particularly limited, and examples thereof include dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and 2,5-dimethyl. -2,5-di (t-
Butylperoxy) hexyne-3, benzoyl peroxide, 2,4-cycloldibenzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxybenzoate, 2,5-dimethyl-2,5 -Di (benzoylperoxy) hexane etc. can be mentioned.

The content of the peroxide crosslinking agent is 0.002-0.03 per 100 g of hydrogenated nitrile rubber.
The hydrogenated nitrile rubber 100 was set in the molar range.
If it is less than 0.002 mol with respect to g, the crosslinking reaction will be insufficient and the elastic modulus of the belt will be low, which will impair the load life and make practical use almost impossible. When it exceeds 0.03 mol, the elastic modulus of the belt is too high, the elongation is small, and the bending life is inferior.

Molecular weight as co-crosslinking agent 500-5000
As the terminal carboxylated liquid 1,2-polybutadiene, it is preferable to use one having a 1,2-bond content of 70% or more. The content of the 1,2-polybutadiene is set in the range of 1 to 7 g per 100 g of hydrogenated nitrile rubber because the load characteristics are deteriorated when the amount is less than 1 g based on 100 g of the hydrogenated nitrile rubber, while the durability is increased when the amount exceeds 7 g. This is because the flexibility and the flex life are inferior.

As described above, in the present invention, a highly hydrogenated nitrile rubber having a hydrogenation rate of 80% or more, preferably 95% or more, and most preferably 98% or more is used. When the hydrogenation rate of the nitrile rubber is high, the cross-linking efficiency of the hydrogenated nitrile rubber with the peroxide-based cross-linking agent is usually poor, and it is necessary to use a large amount of the peroxide-based cross-linking agent for the cross-linking. As a result, the flexibility and tear resistance of the vulcanized rubber are significantly reduced. However, according to the present invention, a hydrogenated nitrile rubber having a high hydrogenation rate is used as the peroxide-crosslinked hydrogenated nitrile rubber composition, and a predetermined amount of the above liquid 1,2-polybutadiene is blended as a co-crosslinking agent. By vulcanizing and adhering such a rubber composition to the tooth cloth 4, the back rubber layer 1 and the tooth rubber layer 3 have not only high heat resistance but also high elastic modulus and are excellent in bending resistance, and thus obtained. The running life of the toothed belt A is significantly improved.

The core wire 2 is made of glass fiber and contains resorcin / formaldehyde precondensate, vinylpyridine-styrene-butadiene (hereinafter abbreviated as Vp) and chlorosulfonated polyethylene (hereinafter abbreviated as CSM) as main components. And treated with the first liquid containing natural rubber or isoprene rubber, and further, nitrile rubber and / or
Alternatively, it is treated with a second liquid containing hydrogenated nitrile rubber, isocyanate and chlorinated rubber.

The glass fiber is not particularly limited, but usually, a glass fiber having a thickness of 5 to 13 μm is coated with a sizing agent composed of an anchoring agent, an adhesive, a surfactant, etc.
A bundle of about 100 bundles is used. Further, as the glass fiber, a high-strength glass composition (for example, U glass composition, S
It is preferable to use a glass composition and a P glass composition) because high strength can be obtained.

As the resorcin-formaldehyde initial condensate constituting the main component of the first liquid, resorcin and formaldehyde oxy-resin obtained by reacting resorcin and formaldehyde in the presence of an alkaline catalyst such as alkali hydroxide, ammonia or amine. A water-soluble initial addition condensation product rich in methyl groups can be preferably used. Resorcin
The weight of pure formaldehyde is preferably 15% by weight or less based on the weight of the solid content of Vp and CSM. Also,
The ratio of resorcin and formaldehyde is 1: 0.5-
Those reacted in the range of 2.5 are preferable. In the present invention, the weight ratio of Vp to CSM is preferably in the range of 9: 1 to 5: 5, and when the amount of Vp is less than this, the adhesiveness is not sufficient, and when it is more than this, fatigue resistance is increased. There is difficulty in sex.

As the above Vp, the weight ratio of vinylpyridine: styrene: butadiene is 10-20: 10-2.
Those of 0:60 to 80 are suitable, and Piratex (trade name, manufactured by Sumitomo Nogatta Co., Ltd.), 0650 (trade name, manufactured by Nippon Synthetic Rubber Co., Ltd.), and Nipol 1218FS (trade name, manufactured by Nippon Zeon Co., Ltd.) can be preferably used. ..

The CSM is not particularly limited, and various commercially available products can be appropriately used.

In the present invention, in addition to these main components, natural rubber or isoprene rubber is further added, and the addition amount is 5 to 20% by weight based on the total solid content of Vp and CSM. The range is preferable, and if it is less than this range, the fatigue resistance at high temperature is not sufficiently improved, and if it exceeds this range, the adhesive strength is lowered, and therefore it is preferable to avoid it. On the other hand, in order to improve the adhesiveness, it is effective to add a little nitrile rubber (hereinafter referred to as NBR), and it is possible to improve the decrease in the adhesiveness due to the addition of natural rubber or isoprene rubber.

The type of natural rubber is not particularly limited, and commercially available products can be used. Further, as the isoprene rubber, Califlex IR-700 (manufactured by Shell Chemical Co.) and Maxprene IR-900 (manufactured by Steel Chemical Industry Co., Ltd.) can be preferably used.

The amount of solids deposited by the treatment of the first liquid is preferably in the range of 15 to 25% by weight with respect to the glass fiber. Below this range, the fatigue performance is not sufficient, and above this range, the adhesiveness is poor. It is not preferable because it becomes unstable.
After this treatment, drying is usually performed in the range of 200 to 350 ° C. When applying such glass fibers as they are to various rubber materials, as is generally done in advance, after twisting the glass fiber bundle with a lower twist, aligning a plurality of them and further twisting them to form a glass cord. Is what you use.

As the NBR contained in the second liquid, commercially available NBR having a nitrile bond content of 20 to 40% can be used. Further, hydrogenated nitrile rubber (referred to as H-NBR) can be used instead of NBR. By using this H-NBR, the adhesive property is excellent and the heat resistance is extremely good, and the H-NBR is particularly suitable for applications requiring high heat resistance. The H-NBR preferably has an unsaturation in the range of 14 to 28.
When the degree of unsaturation is lower than this, the heat resistance is further improved, but the adhesiveness is deteriorated, which is not preferable.

Examples of the isocyanate include methylene diphenyl diisocyanate, toluene diisocyanate, triphenylmethane triisocyanate, naphthalene diisocyanate and the like, and among them, methylene diphenyl diisocyanate having an appropriate film hardness and good adhesiveness is most preferable.

The chlorinated rubber preferably has a chlorination degree of 40-80.

The ratio of isocyanate to NBR or H-NBR is preferably 0.5 to 3 with respect to the isocyanate. If it is less than this range, the coating becomes too hard, and if it exceeds this range, the adhesiveness and adhesion are unstable, which is not preferable. Further, the amount of isocyanate and NBR or H-NBR in the second liquid is preferably in the range of 5 to 15% by weight in terms of solid content, and if it is less than this range, sufficient adhesive strength cannot be obtained. Further, if it exceeds this range, the adhesion becomes unstable, which is not preferable. Further, it is needless to say that NBR and H-NBR can be used in combination, and there is no limitation on the quantitative range thereof. Further, since the second liquid uses chlorinated rubber and has excellent film-forming ability, a rubber-reinforcing material having higher adhesive strength can be obtained. The amount of chlorinated rubber is preferably in the range of 10 to 100% by weight based on NBR or H-NBR. As the vulcanizing agent, various commonly used additives such as zinc white, magnesium oxide, sulfur, and litharge can also be used.

Although drying is performed after the treatment with the second liquid, the drying conditions are not particularly limited, and the drying is performed under general conditions, specifically, 120 to 200 ° C. and 20 to 60 seconds.

The above-mentioned tooth cloth 4 is a resorcin-containing latex component containing at least natural rubber or isoprene rubber.
It is coated with a formalin latex (hereinafter referred to as RFL) composition.

Examples of the latex component include carboxylated NBR latex, chlorosulfonated polyethylene latex, H-NBR latex and vinylpyridine-styrene-butadiene latex. Among them, the H-NBR latex will be described in detail later. The best results were obtained.

The amount of natural rubber or isoprene rubber added is
It is preferably in the range of 5 to 20% by weight with respect to the solid content of the main component latex. If it is less than this range, fatigue resistance cannot be sufficiently improved at high temperatures, and if it exceeds this range, the adhesiveness will be reduced, so avoid it. Is preferred.

An RFL composition containing H-NBR, natural rubber or isoprene rubber in this latex component was used as a tooth cloth 4
To cover. The amount of the RFL composition attached to the tooth cloth 4 is
The content is preferably 5 to 40% by weight, more preferably 10 to 20% by weight, based on the weight of the tooth cloth 4. The control of the adhered amount is performed by the ratio of the solid content of the RFL processing liquid and the gap amount of the squeezing roll during the dip processing. Here, when the adhesion amount is less than 5% by weight, the adhesiveness between the tooth cloth 4 and the rubber or the wear resistance of the tooth cloth 4 decreases, and when it exceeds 40% by weight, conversely, the mechanical properties of the tooth cloth 4 and Flex resistance is reduced.

As described above, the tooth cloth 4 coated with the RFL composition is coated with a glue rubber for adhesion to the tooth rubber layer 3. This glue rubber is an adhesive rubber.

The adhesive rubber may be any of a H-NBR peroxide cross-linking rubber composition and a sulfur-containing rubber composition, such as H-NBR, a peroxide cross-linking agent or a sulfur-containing cross-linking agent. It consists of the required additives to make up the HRH formulation.

As the peroxide-based cross-linking agent, the above-mentioned cross-linking agent is appropriately used, and as the sulfur-containing cross-linking agent, in addition to sulfur, for example, 4,4'-dithiobismorpholine, tetramethylthiuram disulfide, tetra Methyl thiuram monosulfide, 2- (4-monopolynodithio) benzothiazole and the like are used.

Silica, a methylene acceptor and a methylene donor are usually used in the HRH formulation. As the methylene acceptor and the methylene donor, any conventionally known one can be arbitrarily used. Typically, for example, resorcinol or a derivative thereof as a methylene acceptor and hexamethylenetetramine or a derivative thereof as a methylene donor. Is used.

As described above, the adhesive rubber containing the H-NBR, the peroxide type crosslinking agent or the sulfur-containing crosslinking agent and the HRH compound is prepared by dissolving these in an appropriate organic solvent in a state where the H-NBR is unvulcanized. It is a so-called glue rubber, which is usually
With respect to 100 parts by weight of H-NBR, 0.5 to 8 parts by weight of a peroxide-based crosslinking agent or 0.5 to 1 parts by weight of a sulfur-containing crosslinking agent, 1 to 20 parts by weight of silica, 1 to 15 parts by weight of a methylene acceptor, and Contains 1 to 15 parts by weight of methylene donor. As the organic solvent, for example, methyl ethyl ketone is preferably used, but the organic solvent is not limited thereto.

The solvent is usually used in the range of 600 to 900 parts by weight with respect to 100 parts by weight of the rubber composition.
However, the amount of this solvent is also not particularly limited, and is selected so that the viscosity of the obtained adhesive composition is optimum. When the amount of solvent is too small, the viscosity of the obtained adhesive rubber is too high and the workability is poor. On the other hand, when the amount of solvent is too large, the viscosity of the adhesive rubber is too low and the tooth cloth 4 is treated. The amount of adhesion to the cloth 4 is small, and strong adhesion cannot be obtained between the tooth cloth 4 and the tooth rubber layer 3.

Further, the adhesive rubber optionally contains additives such as a filler, a softening agent, a vulcanizing agent, a vulcanization accelerator, a vulcanization aid, an antioxidant and a processing aid. Good.

Next, examples of the present invention will be described more specifically.

Table 1 shows H-N used in the examples of the present invention and the comparative examples.
The unvulcanized component composition of the peroxide-crosslinked rubber composition of BR, the sulfur-containing crosslinked rubber composition of H-NBR, and the chloroprene rubber composition is shown. Table 2 shows the properties of these unvulcanized rubber and vulcanized rubber.

These rubber compositions are used for the back rubber layer 1 and the tooth rubber layer 3, while the adhesive rubber is applied to the nylon tooth cloth 4 and dried, and then the tooth cloth 4 is applied as described above. The toothed belt A is wound around a mold having a tooth groove shape, the core wire 2 and an unvulcanized sheet made of the above rubber composition are wound around the die, subjected to pressure-molding vulcanization treatment in a pressure cooker, and then sliced. The toothed belt A was manufactured by performing the following.

A heat resistant running test, a load endurance running test and a water injection running test were conducted on these toothed belts A, and the heat resistant running life, noise generation time in the heat resistant running test, load endurance life and belt rupture strength remaining rate were examined, respectively. It was
The results are shown in Table 2. In obtaining the data in Table 2, the present invention example 8 in Table 3 was used as the core wire 2, and the present invention example 9 in Table 4 was used as the tooth cloth 4.

The method of measuring each data in Table 2 is as follows.

<Heat resistant running test> A 19 mm wide belt was wound around an idler pulley between a driving pulley and a driven pulley, the driving pulley rotation speed was 3000 rpm, and the belt initial tension was 15 kgf. The belt was run at 140 ° C., and the time from the start of running until the back rubber layer 1 or the tooth rubber layer 3 (root) was cracked was evaluated.

<Noise generation time in heat resistance running test> This is the time until the noise rises by 5 dB or more based on the noise in the initial running (1 to 2 hours).

<Load endurance life> A belt with a width of 10 mm is wound between the driving pulley and the driven pulley, the driving pulley rotation speed is 6000 rpm, and the belt initial tension is 20 kgf.
The belt was run under an atmosphere temperature of 100 ° C. under S, and the time from the start of running until the back rubber layer 1 or the tooth rubber layer 3 (root) was cracked was evaluated.

<Water injection running test> Using the rubber composition shown in Table 1, the tooth pitch was 8 mm, the number of teeth was 109, and the belt width was 1 according to the conventional method.
A 9mm toothed belt A is manufactured, and this toothed belt A is shown in FIG.
The durability test was carried out by winding the device around the belt running durability test device shown in FIG.

In the test apparatus shown in FIG. 2, among the toothed pulleys 10, 10, ... Of 24 teeth arranged in a cross shape, the lower toothed pulley 10 is a driving pulley and the others are driven pulleys. 32 .phi.mm flat pulleys 11, 11, ... Are laid out between the pulleys 10, 10 ,.

The test conditions are as follows.
Apply a dead load of 40 kgf to the (driven pulley) in the direction of the arrow,
After water is dropped onto the lower toothed pulley 10 (driving pulley) at a rate of 1 liter / 1 hr, this toothed pulley 10 (driving pulley) is rotated at 6000 rpm for 1 × 10 ⁶ cycles, and then toothed. The residual strength at break of the belt A was measured.

[0057]

[Table 1]

[0058]

[Table 2]

Table 3 shows the core wire 2 used in the examples of the present invention and the comparative examples.
2 shows the first liquid composition and the second liquid composition, the properties of the core wire 2 treated with these liquid compositions, and the heat resistant running life of the toothed belt A using these core wires 2, etc., respectively. In obtaining the data in Table 3, Invention Example 1 in Table 1 was used as the rubber composition of the back rubber layer 1 and the tooth rubber layer 3, and Invention Example 9 in Table 4 was used as the tooth cloth 4.

<Treatment of core wire> Vp (manufactured by Sumitomo Nogatta Co., Ltd.) containing vinylpyridine, styrene and butadiene in a ratio of 15:15:70 with respect to 320 parts by weight of an addition condensate of resorcin and formaldehyde. Pylatex, solid content 41% by weight 424 parts by weight, chlorosulfonated polyethylene (CSM45 manufactured by Iron and Steel Chemical Co., Ltd.
0, solid content 40% by weight) 188 parts by weight, natural rubber (HA
22 parts by weight of latex, solid content 60% by weight, and 22 parts by weight of ammonia water (25%) were added with stirring, and water was added so as to be 1000 parts by weight as a whole to prepare a first liquid.

According to a conventional method, three glass fiber bundles formed by bundling 200 9 μm glass fibers were pulled out, and the first
Treated with liquid. Solid content adhesion rate at this time is 19% by weight
Met. After this glass fiber bundle was dried at 280 ° C. for 22 seconds, 16 times of twisting was applied per 10 cm, and 13 twists were aligned to perform 8 times of twisting per 10 cm.

The glass cord treated with the first liquid was polyisocyanate (MDI-P manufactured by Mitsui Toatsu Co., Ltd.).
H, metaphenylene diisocyanate type) 36 parts by weight,
H-NBR compound (manufactured by Zeon Corporation, 2020)
60 parts by weight, chlorinated rubber (CR-15, manufactured by Asahi Denka Co., Ltd.) 12
It was treated with a second liquid containing 1 part by weight of Zinc Hua No. 3 as a vulcanizing agent and 891 parts by weight of a solvent consisting of methyl ethyl ketone and toluene, and dried at 155 ° C. for 48 seconds. The solid content deposition rate by the second liquid treatment is 2.3% by weight.
Met.

The method of measuring each data in Table 4 is as follows.

<Tensile strength> Speed: 300 mm / min, Clamping interval: 250 mm, Clamp: Measuring tensile strength of glass cord by winding method <Peeling strength> Treated reinforced glass cord on rubber sheet (thickness 3 mm) Arrange 19 to 20 pieces / 25 mm, cover with a cloth, 150 ° C, 30 minutes, 20 kg / cm ²
Peeling speed of the test piece prepared by vulcanization molding under the pressure of 50 mm
Measured in minutes.

<Water resistance> The treated glass cords were tensioned at a distance of 1 mm with a tension of 5 kg, and two glass cords were aligned, and the rubber composition of Inventive Example 1 of Table 1 and the tooth cloth of Inventive Example 9 of Table 4 were aligned. Using,
Preheat 5 minutes, press molding at 140 ℃ -30 minutes, 5 × 300
Two belts each having a size of 3 mm were combined to form a belt.

The belt was hung on two pulleys of 100 mmφ and 25 mmφ, and a part of the 25 mmφ pulley was immersed in water. After rotating at 1000 rpm for 24 hours, the belt was taken out and its tensile strength was measured. did.

[0067]

[Table 3]

Table 4 shows the tooth cloth 4 used in the examples of the present invention and the comparative examples.
2 shows the data such as the heat-resistant running life of the toothed belt A using the RFL composition coated with the above and the tooth cloth 4 treated with this RFL composition. In obtaining the data in Table 4, Invention Example 1 of Table 1 was used as the rubber composition of the back rubber layer 1 and the tooth rubber layer 3, and Invention Example 8 of Table 3 was used as the core wire 2.

<Coating of Tooth Cloth with RFL Composition> RF
By adjusting the ratio of the solid content of the L composition and the gap amount of the squeezing roll during the dip treatment, the amount of the RFL composition attached to the tooth cloth 4 is set to 30% by weight with respect to the weight of the tooth cloth 4. After dipping and drying at 110 ℃, 220
Heat-treated at ℃.

[0070]

[Table 4]

From the data of Tables 2 to 4, the inventive examples are superior to the comparative examples in all of the heat resistant running life, noise generation during heat resistant running, load endurance life and water injection running test. I understand.

[0072]

As described above, according to the present invention of claim 1, 1,2-polybutadiene is contained in the rubber composition of the back rubber layer and the tooth rubber layer. The durability of the rubber layer can be further enhanced. Furthermore, since natural rubber or isoprene rubber is blended in the first liquid, which is a treatment liquid for the core wire, curing is suppressed and the adhesion of the natural rubber or isoprene rubber to the glass filament is improved to improve the water resistance of the core wire. Can be improved. Also, since natural rubber or isoprene rubber is blended in the latex component that coats the tooth cloth, it is possible to suppress curing and prevent cracking, and at the same time improve the adhesion of the natural rubber or isoprene rubber to the glass filament, and to improve the water resistance of the tooth cloth. It is possible to improve the sex. In addition, N on the core wire surface and the tooth cloth surface
CO can be reacted with the carboxylic acid of the tooth rubber layer to improve the adhesive strength of the three members, and the curing of the belt due to heat aging can be suppressed to reduce noise during belt running.

According to the second aspect of the present invention, since the glass fiber forming the core wire has a high-strength glass composition, the toothed belt can have excellent strength.

[Brief description of drawings]

FIG. 1 is a perspective view of a toothed belt.

FIG. 2 is an explanatory diagram illustrating a procedure of a water injection running test.

[Explanation of symbols]

 1 Back rubber layer 2 Core wire 3 Tooth rubber layer 4 Tooth cloth A Toothed belt

Claims (2)

[Claims] 1. A back rubber layer in which a plurality of core wires are embedded,
A toothed belt comprising a plurality of tooth rubber layers formed on one surface of the back rubber layer and a tooth cloth bonded to the tooth surface of the tooth rubber layer, wherein the back rubber layer and the tooth rubber layer are: Peroxide 0.002-0.0 per 100 g of hydrogenated nitrile rubber
3 mol and 1 to 7 g of a terminal carboxylated liquid 1,2-polybutadiene having a molecular weight of 500 to 5000 as a co-crosslinking agent
Composed of a peroxide-crosslinked hydrogenated nitrile rubber composition containing, the core wire is composed of glass fiber,
Treated with the first liquid containing resorcin / formaldehyde precondensate, vinylpyridine-styrene-butadiene and chlorosulfonated polyethylene as main components, and natural rubber or isoprene rubber added, and further nitrile rubber and / or hydrogenation It is treated with a second liquid containing nitrile rubber, isocyanate and chlorinated rubber, and the above-mentioned tooth cloth is coated with a resorcin-formalin latex composition containing at least natural rubber or isoprene rubber as a latex component. A characteristic toothed belt. 2. The toothed belt according to claim 1, wherein the glass fiber forming the core wire has a high-strength glass composition.