JPH112295A - Power transmission belt - Google Patents

Abstract

(57) [Problem] To provide a power transmission belt that eliminates generation of abnormal noise at the time of operation of the belt, has improved wear resistance, and has a longer life. SOLUTION: At least a part of a rubber part constituting a belt is represented by the following general formula (I) with respect to 100 parts by weight of a sulfur-modified chloroprene rubber: (Wherein, R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms,
At least three of R ¹ , R ² , R ³ and R ⁴ represent a hydrocarbon group having 1 to 12 carbon atoms), 0.1 to 2.5 parts by weight of a thiourea compound represented by the formula: A power transmission belt comprising a rubber composition containing parts by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power transmission belt. More specifically, the present invention relates to a power transmission belt such as a V-ribbed belt or a V-shaped belt.

[0002]

2. Description of the Related Art Power transmission belts are used in power units of industrial machines, automobiles, ships, and the like.

[0003] The performance required of a power transmission belt includes oil resistance, heat resistance, bending resistance, and the like. In order to exhibit these performances, when chloroprene rubber is used for the rubber portion, the rubber is used. Causes stickiness during operation and produces abnormal noise between the belt and the pulley.

In order to prevent generation of abnormal noise, a vulcanizing agent such as zinc oxide and magnesium oxide, a vulcanizing accelerator such as 2-mercaptoimidazoline, and the like are added to chloroprene rubber to obtain a rubber having an increased crosslinking density. It has been proposed to use the composition for a rubber portion of a power transmission belt (Japanese Patent Application Laid-Open No. 59-110944). However, when the rubber composition is used, the generation of abnormal noise can be suppressed to some extent by improving the crosslink density, but a crack is generated in the rubber portion where the rubber composition is used, There is a problem that the life of the power transmission belt is shortened.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and further suppresses the generation of abnormal noise when the belt is operated, improves the abrasion resistance, and further improves the belt. It is an object of the present invention to provide a power transmission belt having a longer life.

[0006]

According to the present invention, at least a part of a rubber part constituting a belt is represented by a general formula (I) based on 100 parts by weight of a sulfur-modified chloroprene rubber.

[0007]

Embedded image

(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ¹ , R ² , R ³ and R ^{4 each represent} At least three of them
The species is a hydrocarbon group having 1 to 12 carbon atoms) and a rubber composition containing 0.1 to 2.5 parts by weight of a thiourea compound represented by the formula (1) and 8 to 50 parts by weight of carbon black. Power transmission belt.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, in the power transmission belt of the present invention, at least a part of the rubber portion constituting the belt has the general formula (I): 100 parts by weight of the sulfur-modified chloroprene rubber.

[0010]

Embedded image

(Wherein, R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ¹ , R ² , R ³ and R ^{4 each represent} At least three of them
The species is a hydrocarbon group having 1 to 12 carbon atoms) and a rubber composition containing 0.1 to 2.5 parts by weight of a thiourea compound represented by the formula (1) and 8 to 50 parts by weight of carbon black. Is what you do.

The power transmission belt of the present invention is particularly characterized in that the thiourea compound represented by the general formula (I) and carbon black are simultaneously used in specific amounts in the rubber composition. Thus, when the thiourea compound and carbon black are contained in the rubber composition, the degree of crosslinking of the sulfur-modified chloroprene rubber is increased based on the action of the thiourea compound,
The heat aging resistance is improved, and the wear resistance is improved based on the action of carbon black, and the bending fatigue of the rubber portion made of the rubber composition is remarkably improved. Therefore, it is considered that the power transmission belt of the present invention suppresses generation of abnormal noise during operation, and further prolongs the life of the belt.

The thiourea compound represented by the general formula (I) is obtained when at ^{least three of} R ¹ , R ² , R ³ and R ⁴ are not a hydrocarbon group having 1 to 12 carbon atoms. Abnormal noise is generated during operation of the power transmission belt, and the life of the belt is shortened. Therefore, in the present invention, R ¹ ,
At least three of R ² , R ³ and R ⁴ have 1 carbon atom
To 12 hydrocarbon groups.

Typical examples of the thiourea compound include:
For example, trimethylthiourea, triethylthiourea, tripropylthiourea, tributylthiourea,
Thiourea compounds having an alkyl group having 1 to 12 carbon atoms such as tetramethylthiourea, tetraethylthiourea, tetrapropylthiourea, and tetrabutylthiourea; aryl groups having 1 to 12 carbon atoms such as phenyldimethylthiourea, phenyltrimethylthiourea, and phenyldiethylthiourea And the like, and these can be used alone or in combination of two or more. Among these thiourea compounds, trimethylthiourea, triethylthiourea and tetramethylthiourea, particularly trimethylthiourea and tetramethylthiourea can be suitably used in the present invention.

If the amount of the thiourea compound used is too small, an abnormal sound will be generated. Therefore, the amount of the thiourea compound is 0.1 parts by weight or more, preferably 0.15 parts by weight, per 100 parts by weight of the sulfur-modified chloroprene rubber. If the amount is more than 2.5 parts by weight, and if the amount is too large, the life of the belt is shortened, the amount is not more than 2.5 parts by weight, preferably not more than 2 parts by weight based on 100 parts by weight of the sulfur-modified chloroprene rubber.

Typical examples of the carbon black include:
For example, furnace black such as HAF, MAF, FEF, SRF, and GPF, and thermal black such as FT and MT are exemplified. Among these, furnace black is preferably used in the present invention.

If the amount of the carbon black is too small, the amount of abrasion of the rubber portion at the time of rubbing with the pulley cannot be sufficiently reduced. Therefore, the amount of the carbon black is 8 parts by weight based on 100 parts by weight of the sulfur-modified chloroprene rubber. Parts or more, preferably 1
0 parts by weight or more, more preferably 12 parts by weight or more,
On the other hand, if the amount is too large, the improvement of the belt life and the improvement of the bending fatigue resistance cannot be expected. Therefore, 50 parts by weight or less, preferably 42 parts by weight or less, more preferably 100 parts by weight of the sulfur-modified chloroprene rubber. 38
Not more than parts by weight.

The present invention has one major feature in that the sulfur-modified chloroprene rubber is used. In the present invention, since the thiourea compound and carbon black are used at the same time as the sulfur-modified chloroprene rubber, the synergistic effect of the thiourea compound and the carbon black further suppresses the generation of abnormal noise during the operation of the belt. There is an advantage that the life is extended.

Representative examples of the sulfur-modified chloroprene rubber include, for example, the following general formula (II):

[0020]

Embedded image

(Where x is an integer of 2 to 6, n is 80x to
Sulfur-modified chloroprene rubber represented by 110x (x represents the same as above). The sulfur-modified chloroprene rubber has a concept including what is generally called G-based neoprene rubber, and a typical example thereof is, for example, Showa Denko Dupont Co., Ltd.
Neoprene GS, Neoprene GNA, Neoprene GW, Neoprene GRT, and the like.

The rubber composition used in the present invention is obtained by adding the above thiourea compound and carbon black to a sulfur-modified chloroprene rubber. If necessary, various additives can be blended.

Examples of the additives include a lubricant such as stearic acid; a crosslinking agent such as sulfur, an organic sulfur compound, a metal oxide such as zinc oxide and magnesium oxide, and a metal peroxide; a thiazole, a dithiocarbamate, and a guanidine. Accelerators such as amines and thiurams; anti-aging agents such as amines and phenols; fillers such as calcium carbonate, basic magnesium carbide, diatomaceous earth, and clay; plasticizers such as dimethyl phthalate, diethyl phthalate, and dioctyl phthalate These are used singly or as a mixture of two or more.

The amount of the additive is not particularly limited, and it is preferable to appropriately adjust the amount according to the type of the additive.

[0025] The power transmission belt of the present invention is characterized in that at least a part of a rubber part constituting the belt is made of the rubber composition, and the rubber composition is used. The rubber portion varies depending on the type of the power transmission belt. Examples thereof include rubber bottoms such as V-shaped belts and V-ribbed belts.

It should be noted that all the rubber components used in the components of the power transmission belt of the present invention may be the above-mentioned rubber composition, and other rubber power transmission belts may be used without impairing the object of the present invention. It may be a combination with the used rubber.

Next, an embodiment of the power transmission belt of the present invention will be described with reference to the following drawings.

FIG. 1 is a schematic sectional view showing an embodiment of a V-ribbed belt which is a kind of power transmission belt of the present invention. In FIG. 1, a bottom rubber 1 is laminated with an adhesive rubber layer 3 in which a cord 2 made of, for example, polyester or aramid is embedded, and an upper surface of the adhesive rubber layer 3 is made of, for example, a rubberized canvas. The cloth 4 is adhered.

The bottom rubber 1, the adhesive rubber layer 3, and the upper cloth 4
The rubber composition can be used as a rubber component. In particular, when the rubber composition is used for the bottom rubber 1, when the rubber composition slides on the pulley 5 provided on the bottom surface of the bottom rubber 1, the generation of abnormal noise can be greatly reduced.

FIG. 2 is a schematic sectional view showing one embodiment of a V-shaped belt which is a kind of the power transmission belt of the present invention.
In FIG. 2, a bottom rubber 6 is laminated with an adhesive rubber layer 3 in which a core wire 2 made of, for example, polyester, aramid or the like is embedded, and an upper surface of the adhesive rubber layer 3 is made of, for example, a rubberized canvas. The cloth 4 is bonded and the bottom rubber 6
A lower cloth 7 made of a rubberized canvas is adhered to a lower surface of the lower cloth.

The rubber composition can be used as a rubber component for the bottom rubber 6, the adhesive rubber layer 3, the upper cloth 4 and the lower cloth 7. In particular, when the rubber composition is used for the bottom rubber 6, when the rubber composition is rubbed with the pulley 5, the generation of abnormal noise can be greatly improved.

As described above, in the present invention, it is preferable to use the rubber composition for the rubber portion of the surface of the power transmission belt that comes into contact with the pulley in order to prevent generation of abnormal noise.

In the power transmission belt of the present invention, since at least a part of the rubber portion constituting the belt is made of the rubber composition, noise caused by contact with the pulley when the belt is operated is generated. Generation is suppressed, and the life of the belt can be prolonged.

As described above, the power transmission belt of the present invention is shown in FIGS.
However, the present invention is not limited to only the embodiments shown in the drawings.

[0035]

Next, the power transmission belt of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Examples 1 to 3 and Comparative Examples 1 to 4 8 parts by weight of dioctyl sulfonate as a plasticizer were added to 100 parts by weight of a sulfur-modified chloroprene rubber (manufactured by DuPont, Showa Denko KK, trade name: Neoprene GRT). 5 parts by weight of zinc oxide and 4.8 parts by weight of magnesium oxide as a cross-linking agent, and 1 part by weight of stearic acid as a lubricant were added, and trimethylthiourea and carbon black FEF were added thereto in amounts shown in Table 1 (sulfur-modified chloroprene rubber 100%). (Compared to Comparative Examples 1-3 without trimethylthiourea and Comparative Example 4 without carbon black FEF) and kneaded for about 5 minutes with a Banbury mixer. To obtain a rubber composition.

Next, as shown in FIG.
(Polyester, 1 mm diameter) embedded rubber rubber layer 3 and bottom rubber 1 are made of the obtained rubber composition, they are laminated, and a canvas is adhered to the upper surface of adhesive rubber layer 3 to form a power transmission belt. I got it.

The life of the obtained power transmission belt was evaluated for belt life, tackiness, generated noise, and abrasion resistance, and the performance of the rubber member was evaluated for elongation retention after aging according to the following methods. Table 1 shows the results.

(1) Performance of Power Transmission Belt Belt Life As shown in FIG.
A power transmission belt 10 is wound around a driven pulley 9 having a diameter of 120 mm, and the idle pulley 11 having a diameter of 70 mm and the idler pulley 12 having a diameter of 45 mm are applied thereto.
With the set weight (tension) of 85 kgf and the rotation speed of the drive pulley 8 set to 4900 rpm, the power transmission belt 10 was run in the direction of arrow A in an atmosphere of 85 ° C., and the time until cracks were generated was measured. Is the belt life.

Adhesion In the same manner as the belt life measuring method, the power transmission belt 10 shown in FIG.
Inspect the inner surface of the power transmission belt for tackiness.

Generated Sound The power transmission belt 10 shown in FIG. 3 is run in the same manner as the belt life measuring method, and after one hour,
A microphone is installed at a position 10 cm away from the pulley, and the sound pressure level is checked with a sound level meter.

Abrasion resistance As shown in FIG. 4, the driving pulley 1 having a diameter of 120 mm
The power transmission belt 10 is wound around a driven pulley 14 having a diameter of 3 mm and a diameter of 120 mm.
Dead weight (DW) 100kgf, drive pulley 1
3, the power transmission belt 10 was run in the direction of arrow B in an atmosphere of 25 ° C. at a rotation speed of 5100 rpm, and after 24 hours, the loss and abrasion loss of the power transmission belt (vol%)
Is measured, and this is defined as an index of wear resistance.

(2) Performance of Rubber Member Elongation Retention after Aging Under the conditions of an aging temperature of 120 ° C. and an aging time of 144 hours, J
The residual ratio (%) is checked according to the “aging test” specified in IS K6301, and this is defined as the retention ratio (%).

[0044]

[Table 1]

From the results shown in Table 1, all of the power transmission belts obtained in Examples 1 to 3 hardly generate stickiness during operation, and generate noise (unusual noise) during operation. It can be seen that the belt is small, has excellent wear resistance, and has a long belt life.

[0046]

According to the power transmission belt of the present invention, there is almost no generation of abnormal noise when the belt is operated, and the wear resistance is improved to further extend the life.
For example, it can be suitably used for power units of industrial machines, automobiles, ships, and the like.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a V-ribbed belt, which is one type of a power transmission belt of the present invention.

FIG. 2 is a schematic cross-sectional view showing one embodiment of a V-shaped belt which is a kind of the power transmission belt of the present invention.

FIG. 3 is a schematic explanatory view of a device used for examining the performance of the power transmission belt obtained in the example of the present invention and the comparative example.

FIG. 4 is a schematic explanatory view of an apparatus used for examining the performance of the power transmission belt obtained in the example of the present invention and the comparative example.

[Explanation of symbols]

 10 Power transmission belt

Claims (3)

[Claims] At least a part of a rubber part constituting a belt is represented by the following general formula (I) with respect to 100 parts by weight of a sulfur-modified chloroprene rubber: (Wherein, R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms,
At least three of R ¹ , R ² , R ³ and R ⁴ represent a hydrocarbon group having 1 to 12 carbon atoms), 0.1 to 2.5 parts by weight of a thiourea compound represented by the formula: A power transmission belt comprising a rubber composition containing parts by weight. 2. The power transmission belt according to claim 1, wherein the amount of carbon black is 10 to 42 parts by weight based on 100 parts by weight of the sulfur-modified chloroprene rubber. 3. The power transmission belt according to claim 1, wherein the rubber portion constituting the belt is a bottom rubber that comes into contact with the pulley.