JPH11264447A - Polyurethane belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the friction coefficient of a belt surface in engaging the belt with a pulley and to suppress sound generation by adding fat and oil in a polyurethane elastic body. SOLUTION: A friction transmission belt has a tensile body rope 3 spirally embedded therein and a V-shaped projection part is integrally formed with the main body 1 in the internal face of the belt main body 1. A polyurethane elastic body constituting the belt main body is constituted of toluenediisocianate as isocianate and polytetramethyleneglycol as polyore. Among resins added to the elastic body are lard and beef tallow as animal solid fat and coconut oil as vegetable solid fat. The oil and fat are oozed out onto the surface of the belt and lower the friction coefficient of the belt surface so as to suppress the sound generation. As for a polyurethane toothed belt, the oil and fat are preferably added 0.5-10 pts.wt. to polyurethane 100 pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane belt, and more particularly to a polyurethane belt which prevents generation of noise and improves light resistance of the polyurethane belt.

[0002]

2. Description of the Related Art Conventionally, rubber or polyurethane has been used as a material of a power transmission belt for transmitting power or a transport belt for transporting paper sheets such as cards. Rubber has a problem of poor appearance. On the other hand, polyurethane belts have better appearance than rubber, and the range is wide because there is no disadvantage of dropping abrasion debris around the rubber belt like rubber fall. .

However, a disadvantage of polyurethane is discoloration due to ultraviolet rays. Polyurethane is discolored when exposed to ultraviolet light for a long period of time, resulting in poor appearance. For that, polyurethane belts are
Even when stored indoors as well as outdoors, it may be discolored by ultraviolet light during lighting from windows and lighting such as fluorescent lamps, and it may be discolored during use, or after being manufactured as a belt There is a problem that it cannot be stored for a long time. Therefore, there has been proposed a urethane belt in which light resistance is improved by adding a benzotriazole-based ultraviolet absorber and a hindered phenol-based antioxidant to polyurethane.

[0004] Polyurethane belts using a polyurethane to which a benzotriazole-based ultraviolet absorber and a hindered phenol-based antioxidant are added, although the discoloration when exposed to ultraviolet rays is slightly reduced, it is still satisfactory. Instead, further improvements were desired.

[0005] Therefore, by adding a benzotriazole-based ultraviolet absorber, a hindered amine-based ultraviolet stabilizer and a hindered phenol-based antioxidant to polyurethane, the synergistic effect of the ultraviolet absorber and the ultraviolet stabilizer is large, and Can greatly suppress discoloration due to
The change with time of the appearance of the belt could be minimized. (Disclosed in Japanese Patent Publication No. Hei 8-16504)

[0006]

Further, a toothed belt made of polyurethane is used for a carriage belt of a printer or for feeding a facsimile paper in an office or the like where quietness is required. In this case, a problem may occur when a sound "pickling" or "squeaking" is generated in a state of engagement with the pulley. Also, in the case of a toothed belt made of polyurethane for bicycles, which is subjected to a high load at a low rotation speed, when the belt meshes with a resin pulley or when the belt comes into contact with the flange of the pulley, the sound "clicks" or "squeezes". There was a sound.

Polyurethane V used for NC lathes, etc.
For the belt, if the belt separates from the pulley when the belt is engaged with the pulley, or if the friction coefficient of the belt is too high, the belt will stick to the pulley and it will be difficult to separate, so a "pip" sound will be generated. Was. Even if the alignment (parallelism) of the pulley was slightly out of order, a "pip" sound was also generated due to the high friction coefficient of the polyurethane.

The polyurethane V-ribbed belt is used as a belt for moving the massaging machine of the massaging machine up and down. When the massaging machine is used, a "pitch" sound may be generated while moving the massaging machine. It was harsh for me. This phenomenon also occurs when the belt separates from the pulley or when the pulley is out of alignment, as in the case of the polyurethane V-belt.

Further tests were conducted by adding molybdenum disulfide as a lubricant. Since molybdenum disulfide is a solid, it does not migrate to the belt surface when molded into a belt.
Furthermore, since molybdenum disulfide has a large specific gravity, it was extremely difficult to expose molybdenum disulfide to the tooth surface of a toothed belt in a toothed belt. Exposure to the surface of the part or the surface of the V-rib part was a very difficult technique.

The object of the present invention is to minimize the discoloration of the polyurethane belt even when used or stored under the conditions of exposure to ultraviolet light, to minimize the change with time in appearance, It is an object of the present invention to provide a polyurethane belt that suppresses sound generation when engaged.

[0011]

According to the present invention, there is provided a belt made of a polyurethane elastic body having a core wire embedded in a belt body along a longitudinal direction in order to achieve the above object. It is a polyurethane belt obtained by adding fats and oils to a polyurethane elastic body. If the polyurethane belt according to claim 1 is used, the friction coefficient of the belt surface can be reduced by the action of the oil on the belt surface even when the belt and the pulley are engaged or the pulley alignment is incorrect by adding oil or fat to the polyurethane. By lowering the pronunciation can be suppressed.

According to the second aspect of the present invention, there is provided the polyurethane belt according to the first aspect, wherein the fat or oil is lard. The use of lard as oils and fats reduces the coefficient of friction on the belt surface by depositing lard on the belt surface, which can further reduce noise when the belt and pulley are engaged or when pulley alignment is incorrect. it can.

According to a third aspect of the present invention, there is provided the polyurethane belt according to the first or second aspect, wherein 0.5 to 7 parts by weight of fat is added to 100 parts by weight of the polyurethane. By limiting the amount of fats and oils, it is possible to sufficiently suppress the generation of sound without lowering the physical properties of the polyurethane elastic body.

According to the fourth aspect of the present invention, at least 0.08 to 1.6 parts by weight of a benzotriazole-based ultraviolet absorber and 0.08 to 1.6 parts by weight of a hindered amine-based ultraviolet stabilizer are added to 100 parts by weight of the polyurethane. 6 parts by weight, and a hindered phenolic antioxidant of 0.04 to
The polyurethane belt according to any one of claims 1 to 3, further comprising 0.8 parts by weight of a blended light stabilizer. According to the fourth aspect of the present invention, the generation of sound can be suppressed, and the addition of the above-mentioned amount of the light-resistant stabilizer can significantly suppress discoloration due to ultraviolet rays, and can reduce the temporal change in the appearance of the belt. It can be reduced as much as possible.

According to the fifth aspect of the present invention, the belt is a toothed belt in which teeth and grooves are alternately formed at a constant pitch inside the belt, and a tensile member is embedded at a pitch line position. According to the invention as set forth in claim 5, by adding fats and oils to the polyurethane toothed belt, it can be used for a carriage belt for a printer or for facsimile paper feeding in a place such as an office where quietness is required. When used as a polyurethane belt for bicycles, the sound can be reduced even when used as a toothed belt.

According to a sixth aspect of the present invention, there is provided a friction transmission belt in which the belt has at least one V-shaped protrusion or V rib extending in the belt circumferential direction and formed integrally with the main body. According to the sixth aspect of the present invention, by adding oil and fat to the polyurethane friction transmission belt, no sound is generated because the belt does not stick to the pulley when the belt is separated from the pulley when the belt is engaged with the pulley. .

[0017]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a toothed belt made of polyurethane of the present invention, in which (a) is a partially cutaway perspective view, and (b) is a cross-sectional view.
Are alternately provided, and a core wire 3 made of glass fiber, polyester fiber, aramid fiber, or the like is embedded on the belt pitch line. FIGS. 2A and 2B show a polyurethane toothed belt for a bicycle according to the present invention, wherein FIG. 2A is a partially cutaway perspective view, and FIG. 2B is a cross-sectional view. The configuration of the cords is the same as that of the polyurethane toothed belt. However, in the belt groove 6,
A protective layer 4 having a thickness of 0.1 to 1.0 mm for protecting the core is provided between the core 3 and the surface of the belt groove adjacent to the core 3.

FIG. 3 is a perspective view of the polyurethane V-belt of the present invention, FIG. 4 is a perspective view of the polyurethane V-ribbed belt of the present invention, and FIG. 5 is a perspective view of the polyurethane truncated V-ribbed belt of the present invention. It is. In the friction transmission belt of the present invention, a tension rope 3 made of polyester, aramid (trade name: Kevlar), nylon, glass fiber, or the like is spirally embedded in the belt main body in the belt longitudinal direction. At least one V-shaped projection extending in the belt circumferential direction is formed integrally with the belt main body 1 on the inner peripheral surface of the belt.

Here, the polyurethane elastic body constituting the belt body is composed of isocyanate such as toluene diisocyanate and methylene diisocyanate, and polyols such as polytetramethylene glycol and adipate.

The polyurethane elastomer is a composition having improved light stability, and a light stabilizer is added in an amount of 0.2 to 4.0 parts by weight based on 100 parts by weight of the polyurethane. The light stabilizer used in the present invention comprises three components: a benzotriazole-based ultraviolet absorber, a hindered amine-based ultraviolet stabilizer, and a hindered phenol-based antioxidant. Examples of the agent include methyl-3- [3
-T-butyl-5- (2H-benzotriazole-2-
Yl) -4-hydroxyphenyl] propionate and polyethylene glycol. Examples of the hindered amine ultraviolet stabilizer include bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate. Further, as a hindered phenol-based antioxidant, for example, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] can be mentioned.

The addition amount of each of the three components is 0.08 to 1.6 parts by weight of the benzotriazole-based UV absorber and 100 parts by weight of the hindered amine-based UV stabilizer based on 100 parts by weight of the polyurethane. 08 to 1.6 parts by weight, and the hindered phenol-based antioxidant is 0.04 parts by weight.
Preferably it is in the range of 〜0.8 parts by weight. If the amount of the benzotriazole-based ultraviolet absorber among these additives is less than 0.08 parts by weight, the effect on discoloration is lost, and if it exceeds 1.6 parts by weight, the physical properties of urethane are reduced.

If the amount of the hindered amine ultraviolet stabilizer is less than 0.08 parts by weight, the effect on discoloration is lost, and if it exceeds 1.6 parts by weight, the physical properties of urethane are undesirably deteriorated. Further, if the amount of the hindered phenolic antioxidant is less than 0.04 parts by weight, there is a problem that the physical properties of the urethane cannot be maintained after exposure to sunlight. Is undesirably reduced.

Further, the polyurethane elastic body is a composition to which fats and oils are added. The fats and fats include lard (pork tallow) and beef tallow as animal solid fats, and coconut oil as a vegetable solid fat. Fats and oils are preferable because they ooze out on the belt surface and lower the friction coefficient of the belt surface. In particular, lard (triglyceride rich in saturated fatty acids) has a molecular weight of 800.
It is preferable as a persistent lubricant because it passes through the soft segment of urethane at an appropriate speed and deposits on the polyurethane surface. Here, the molecular weight is 50
If it is less than 0, the lubricant is consumed early, and if the molecular weight is more than 2,000, the lubricant moves at a slow speed in the soft segment, so the effect of the lubricant does not appear early and the sound is generated early. There is a problem to do. further,
Lard (triglyceride containing a large amount of saturated fatty acids) is most preferable in view of the mixing cost and workability.

As a method of adding fats and oils to the urethane prepolymer, for example, in the case of lard, the melting point is 30 to 38 °.
C. After larding the mixture to a higher temperature to make it into a liquid state, adding it to the urethane prepolymer, stirring it, mixing it with a curing agent, and immediately casting it. It is molded into a belt sleeve and then cut to a predetermined width to obtain a polyurethane toothed belt. Polyurethane friction transmission belts are obtained in a similar manner.

The above molding method is not particularly limited.
Normal casting method, or rotating the inner mold and the outer mold at a predetermined number of revolutions, casting the above mixture, filling the cavity between the inner mold and the outer mold with centrifugal force to fill the liquid Centrifugal molding method in which cross-linking is performed at the above temperature. As the mold used for the above-mentioned polyurethane toothed belt, at least an outer mold and an inner mold are used, and the inner peripheral surface of the outer mold is usually flat. As the inner mold, a cylinder or a column having a plurality of grooves arranged in the longitudinal direction is used.

Further, at least an outer mold and an inner mold are used for the mold used for the polyurethane friction transmission belt.
On the inner peripheral surface of the outer mold, a V-shaped or V-shaped
A groove having a truncated shape or a groove having a flat inner peripheral surface is used. In addition, the inner mold may be a cylindrical or cylindrical inner mold having a flat outer peripheral surface, or a cylindrical or cylindrical inner mold in which a plurality of rectangular projections are uniformly arranged in the longitudinal direction on the outer peripheral surface. Is also good.

When an outer mold having a flat inner peripheral surface is used, the sleeve is formed and then ground or polished to form a belt V-shaped portion or V-rib portion.

With respect to the amount of fats and oils to be added, in the case of a toothed belt made of polyurethane, it is preferable to add 0.5 to 10 parts by weight of fats and oils to 100 parts by weight of polyurethane. Here, if the amount of the fat or oil is less than 0.5 part by weight, the effect of the fat or oil is small, and it is difficult to suppress the sound generation. If the amount of the fat or oil exceeds 10 parts by weight, the physical properties of the polyurethane elastic body are reduced. And the life of the toothed belt is shortened.

In the case of a friction transmission belt made of polyurethane, 0.5 to 7 parts by weight based on 100 parts by weight of polyurethane.
It is preferable to add parts by weight of fats and oils. Here, if the amount of the fat or oil is less than 0.5 part by weight, the effect of the fat or oil is small,
If it is difficult to suppress sound generation, and if the added amount of fats and oils exceeds 7 parts by weight, a friction transmission belt that requires a high transmission force will slip and cannot transmit a predetermined power.

[0030]

EXAMPLE 1 In Example 1, 3,3'-dichloro-4,4'-diaminodiphenylmethane was used as a curing agent in 100 parts by weight of a polyether-based urethane prepolymer, and 100 parts by weight of polyurethane was used as a light stabilizer. 2 parts by weight of a mixture of an absorbent, a hindered amine-based UV stabilizer and a hindered phenol-based antioxidant in a blend ratio of 2: 2: 1 are added as a light-resistant stabilizer, and lard is added as an oil or fat at 10 parts by weight. An S3M type toothed belt made of a partially added material was used. As Example 2, 100 parts by weight of the prepolymer of Example 1 was mixed with polyurethane 100 as a curing agent of Example 1 and a light stabilizer.
0.2 parts by weight of a benzotriazole-based UV absorber, a hindered amine-based UV stabilizer, and a hindered phenol-based antioxidant mixed at a blend ratio of 2: 2: 1 to parts by weight. And lard was added in an amount of 0.5 part by weight.

As Comparative Example 1, a toothed belt of the S3M type made of polyurethane alone without adding a light stabilizer and a lubricant was used. Polyurethane 10 as Comparative Example 2
A blend ratio of a benzotriazole-based UV absorber and a hindered phenol-based antioxidant to 0 parts by weight is 1: 1.
Was used, and an S3M type toothed belt composed of 2 parts by weight of a mixture added as a light stabilizer was used. At this time,
10 parts by weight of lard was added as an oil or fat to 100 parts by weight of polyurethane. Polyurethane 10 as Comparative Example 3
A mixture of 0 parts by weight of a benzotriazole-based UV absorber, a hindered amine-based UV stabilizer and a hindered phenol-based antioxidant in a blending ratio of 2: 2: 1 is used as a light stabilizer. An S3M type toothed belt made by adding parts by weight was used. At this time, lard was added as an oil or fat to 100 parts by weight of polyurethane,
0 parts by weight were added. As Comparative Example 4, polyurethane 100
The blending ratio of a benzotriazole-based UV absorber, a hindered amine-based UV absorber and a hindered phenol-based antioxidant to 100 parts by weight of the polyurethane as a curing agent of the example and a light-resistant stabilizer in 100 parts by weight of the polyurethane is 2: 2: 1. And 2 parts by weight of a light-resistant stabilizer were added. At this time, no fat was added.

The belts of Examples 1 and 2 and Comparative Examples 1 to 3 were subjected to an accelerated discoloration test (sunshine test). The accelerated discoloration test (sunshine test) used a sunshine carbon weather meter, and the temperature condition was 63 ± 3 ° C. The discoloration determination method uses a Hunter color difference equation, and the measured values are L, a, b, ΔL, Δa, Δb,
Using L, a, and b of the sample before the sunshine test using ΔE (H) as a reference value, the color difference ΔE (H) is calculated as follows: Color difference ΔE (H) = [(ΔL) ² + (Δa) ² + (Δb)
² ] The color difference ΔE (H) calculated with the formula of ^1/2 with respect to the sunshine time
Was graphed. FIG. 8 shows the result.

In Comparative Example 1 in which nothing was added, discoloration occurred at a rate 12 times or more higher than that in Example 1 in which 2 parts by weight of the light stabilizer was added. Furthermore, at the convergence point of discoloration, the degree of discoloration in Comparative Example 1 is doubled as compared with Example 1. Also,
The degree of discoloration of Examples 1 and 2 is considerably smaller than that of Comparative Examples 2 and 3. Therefore, in order to sufficiently prevent discoloration, it is necessary to add 0.2 parts by weight of a light-resistant stabilizer to 100 parts by weight of polyurethane, and it is necessary to add a benzotriazole-based ultraviolet absorber, a hindered amine-based ultraviolet stabilizer, and a hindered amine. It consists of three components of a dophenol-based antioxidant, and it is essential to add three components of a benzotriazole-based ultraviolet absorber.

Next, a sound generation test was performed using a noise measuring test machine as shown in FIG. As a motor, a sound pressure was evaluated using a hybrid stepping motor that is actually used for facsimile paper feeding. In FIG. 9, the toothed belt 1 is suspended between a driving pulley 14 and a driven pulley 15, and a tension is applied to the toothed belt 1 by using an LM guide 20 as a handle 18 for adjusting the distance between the shafts. Was applied with a torque of 1 kg · cm. And the pulse oscillator is 670p. p. s. And set the oscillation frequency of the stepping motor 21 to operate the PM driver.
Was rotated. Then, as shown in FIG. 9B, the sound was measured by a normal sound level meter at a distance of 20 mm from the drive pulley 14. At this time, the number of teeth of the driving pulley 14 is 17
The number of teeth of the teeth and the driven pulley was 46. Table 1 shows the results.

[0035]

[Table 1]

As is clear from Table 1, the belt of Example 1 in which 10 parts by weight of lard was added to 100 parts by weight of polyurethane was 7 d in comparison with Comparative Examples 1 and 4.
It is considered that the sound pressure decreases as B, and the sound pressure becomes sufficiently quiet as compared with the comparative example. The belt of Example 2 in which lard was added in an amount of 0.5 part by weight with respect to 100 parts by weight of polyurethane had a lower sound pressure than Comparative Example 1 and Comparative Example 4, but compared with Example 1, It is closer to Example 1 and Comparative Example 4, and it can be seen that when the amount of lard added is smaller than this, it is almost the same as the state where lard is not added.

A blend ratio of a benzotriazole-based UV absorber, a hindered amine-based UV stabilizer and a hindered phenol-based antioxidant to 100 parts by weight of polyurethane having the same composition as that of the toothed belt of Example 1 was 2 : A mixture prepared in a ratio of 2: 1, 2 parts by weight as a light stabilizer, and a polyurethane composition in which lard was mixed as a fat or oil with 0.5 part by weight was used to form a sheet. Example 4 is a light-resistant stabilizer prepared by mixing 100 parts by weight of polyurethane with a blend ratio of a benzotriazole-based UV absorber, a hindered amine-based UV stabilizer and a hindered phenol-based antioxidant in a ratio of 2: 2: 1. 3 parts by weight, and lard as fat and oil
A sheet prepared in the same manner as in Example 3 was prepared by using 0 wt.
5 parts by weight of a mixture of a benzotriazole-based UV absorber, a hindered amine-based UV stabilizer and a hindered phenol-based antioxidant in a weight ratio of 2: 2: 1 was added to the parts by weight as a light stabilizer. Using
Further, lard added with 15 parts by weight as fats and oils was used. As Comparative Example 6, a mixture of 100 parts by weight of polyurethane and a blend ratio of a benzotriazole-based ultraviolet absorber, a hindered amine-based ultraviolet stabilizer and a hindered phenol-based antioxidant in a ratio of 2: 2: 1 was used. 3 parts by weight of a light stabilizer were added, and 15 parts by weight of lard was further added as an oil or fat.

Using the sheets of Example 3, Example 4, and Comparative Example 5, static properties were evaluated. The sheet preparation conditions are as follows. Raw material temperature: 60 ° C Cure condition: 110 ° C × 3 hrs + 60 ° C × 24
hrs

[0039]

[Table 2]

As can be seen from Table 2, Example 3 in which the amount of the light stabilizer was 2.0 parts by weight based on 100 parts by weight of the polyurethane and the amount of lard was also 10 parts by weight.
And the amount of the light stabilizer was 3.0 parts by weight, and the amount of the lard was 10 parts by weight, as compared with Example 4 in which the amount of the lard was 10 parts by weight. Is 5.
In Comparative Example 5, which is 0 parts by weight, the physical properties are deteriorated, and the light stabilizer must be within 4.0 parts by weight based on 100 parts by weight of the polyurethane. Further, even when the amount of the light stabilizer was 3.0 parts by weight, Comparative Example 6, in which 15 parts by weight of lard was added, also had deteriorated physical properties. It is necessary to be within.

Next, in Example 5, as a compounding of a toothed belt made of polyurethane for bicycles, 100 parts by weight of a polyether-based urethane prepolymer was mixed with 3,3'-dichloro-4,4'-diaminodiphenylmethane as a curing agent and light fastness. 100 parts by weight of polyurethane mixed with a benzotriazole-based UV absorber, a hindered amine-based UV stabilizer and a hindered phenol-based antioxidant in a blending ratio of 2: 2: 1 to 100 parts by weight of polyurethane as a light-resistant stabilizer A toothed belt for bicycles of S8M type was used, which was obtained by adding 2 parts by weight of lard and further adding 10 parts by weight of lard as oil and fat. As Example 6, the prepolymer 10 of Example 5
0 parts by weight of the curing agent of Example 5 and 100 parts by weight of the prepolymer as a light stabilizer Stabilizer of Example 5 and 100 parts by weight of the prepolymer as a light stabilizer Stabilized ultraviolet absorber and hindered amine ultraviolet light A mixture of a stabilizer and a hindered phenol-based antioxidant in a blend ratio of 2: 2: 1 is used as a light-resistant stabilizer in an amount of 0.1.
2 parts by weight were added and lard was further added at 0.5 part by weight.

As Comparative Example 7, a toothed belt for bicycles of the S8M type comprising only a polyurethane to which no light stabilizer and oil was added was used. Comparative Example 8: S8M comprising 100 parts by weight of polyurethane and 2 parts by weight of a light-resistant stabilizer of a mixture of a benzotriazole-based ultraviolet absorber and a hindered phenol-based antioxidant in a blend ratio of 1: 1. A type of bicycle toothed belt was used. At this time, lard was used as fat and oil in polyurethane 10
10 parts by weight were added to 0 parts by weight. As Comparative Example 9, a blend ratio of a benzotriazole-based UV absorber, a hindered amine-based UV stabilizer and a hindered phenol-based antioxidant to 100 parts by weight of polyurethane was 2:
A toothed belt for bicycles of S8M type was used, which was prepared by adding 0.1 parts by weight of a mixture of 2: 1 as a light stabilizer. At this time, lard was added as an oil and fat in an amount of 10 parts by weight based on 100 parts by weight of the polyurethane. Comparative Example 1
The blending ratio of a benzotriazole-based UV absorber, a hindered amine-based UV stabilizer and a hindered phenol-based antioxidant to 100 parts by weight of polyurethane and 100 parts by weight of polyurethane as a light stabilizer was 100% by weight of polyurethane. : 2: 1 parts by weight of a mixture of 2: 1 was added as a light stabilizer. At this time, no fat was added.

In a sound tester using the actual bicycle shown in FIG. 10, the belts of Examples 5 and 6 and Comparative Examples 7 and 10 were attached to the actual bicycle, the vehicle speed was 10 km / h, and the belt tension (effective tension). 22kgf, temperature and humidity condition 25 °
C, a test was performed at 60%, and a test of the sound generation status for each belt length was performed. Here, the timing belt 26 is driven by the motor 27, and the timing belt 26 is driven, so that the toothed belt 7 made of polyurethane for bicycles is used.
Rotates. The vehicle speed was changed by changing the frequency of the motor 27, thereby changing the number of revolutions of the toothed belt 7 made of polyurethane for bicycles. Further, a powder brake 30 was installed, and a brake was applied to the rear wheel 31 by the roll 28 through the belt 29 to calculate an effective tension applied to the bicycle polyurethane synchronous belt 7 from the torque of the powder brake 30. Then, the bicycle polyurethane toothed belt 7 was rotated under the above conditions, and the sound generation status was checked using a stethoscope 25. FIG. 11 shows the result. As a measuring method, a stethoscope 25 was used to measure the belt at the entrance and exit of the belt on the drive pulley 23, and the maximum sound generation state was plotted.

As is apparent from FIG. 11, the belt to which lard was added at 10 parts by weight with respect to 100 parts by weight of polyurethane did not produce any sound. In contrast, the belt without any lard produced an audible "squeaking" sound. Further, the belt in which 0.5 part by weight of lard was added to 100 parts by weight of polyurethane was in a range where it could not be heard by ears, but a slight sound was heard when heard with a stethoscope. Therefore, it is understood that 0.5 parts by weight is a limit within a range that cannot be heard by the ear, and it can be seen that when the addition amount of lard is smaller than this, the sound level becomes large enough to be heard by the ear.

A blend ratio of a benzotriazole-based ultraviolet absorber, a hindered amine-based ultraviolet stabilizer and a hindered phenol-based antioxidant to 100 parts by weight of polyurethane having the same composition as that of the toothed belt of Example 5 was 2 : A mixture prepared in a ratio of 2: 1, 2 parts by weight as a light stabilizer was added, and a polyurethane composition in which lard was mixed as a fat or oil by 0.5 part by weight was used to form a sheet. Example 8 is a light-resistant stabilizer prepared by mixing 100 parts by weight of polyurethane with a blend ratio of a benzotriazole-based UV absorber, a hindered amine-based UV stabilizer and a hindered phenol-based antioxidant in a ratio of 2: 2: 1. 3 parts by weight, and lard as fat and oil
A sheet prepared in the same manner as in Example 7 was prepared by using 0 wt.
A mixture of 0 parts by weight of a benzotriazole-based UV absorber, a hindered amine-based UV stabilizer and a hindered phenol-based antioxidant in a blending ratio of 2: 2: 1 is 5 parts by weight as a light stabilizer. What was added was used, and what added lard as a fat and oil was further added. As Comparative Example 12, polyurethane 100
3 parts by weight of a hazetriamine-based ultraviolet stabilizer and a hindered phenol-based antioxidant mixed at a ratio of 2: 2: 1 as a light-resistant stabilizer were added to the parts by weight as a benzotriazole-based ultraviolet absorber. Then, lard added as a fat and oil in an amount of 15 parts by weight was used.

Examples 7 and 8 and Comparative Example 11
Using the sheet of Comparative Example 12, the static properties were evaluated. The sheet preparation conditions were the same as the sheet preparation conditions for the compounding of the polyurethane toothed belt.

[0047]

[Table 3]

As can be seen from Table 3, the amount of the light stabilizer added was 2.0 parts by weight with respect to 100 parts by weight of polyurethane even in the compounding of polyurethane used for the toothed belt made of polyurethane for bicycles. Example 7 in which the addition amount is also 10 parts by weight, and the addition amount of the light stabilizer is 3.
Compared to Example 8 in which the amount of lard was 0 part by weight and the amount of lard was 10 parts by weight, but the amount of light-resistant stabilizer was 5.0 parts by weight as compared with Example 8 in which the amount of lard was 10 parts by weight. Example 1
No. 1 has deteriorated physical properties, and the light stabilizer is polyurethane 1
It is necessary to be within 4.0 parts by weight with respect to 00 parts by weight.

In Example 9, 100 parts by weight of a polyether-based urethane prepolymer, 3,3'-dichloro-4,4'-diaminodiphenylmethane as a curing agent and 100 parts by weight of a polyurethane as a light stabilizer, a benzotriazole type ultraviolet absorber And a hindered amine-based UV stabilizer and a hindered phenol-based antioxidant in a blend ratio of 2: 2: 1 were added in an amount of 2 parts by weight as a light-resistant stabilizer, and 7 parts by weight of lard was added as an oil or fat. A V-ribbed belt made of polyurethane made of the above was used. At this time, a 200-J-4 belt was used as the polyurethane V-ribbed belt. This belt had a belt length of 20 inches, a belt shape of J shape, and a number of ribs of 4 ribs. As shown in FIG. 6, the belt type J type has a rib pitch P of 2.34 mm, a rib angle θ of 40 °, and a thickness H of 2.
3 mm, rib bottom thickness T is 1.7 mm, total thickness H + T is 4.
This is a belt having a size of 0 mm. As Example 10, 100 parts by weight of the prepolymer of Example 9 and 100 parts by weight of polyurethane as the curing agent and light stabilizer of Example 9 were used as a benzotriazole-based ultraviolet absorber, a hindered amine-based ultraviolet stabilizer, and a hindered phenol-based compound. A mixture of antioxidants at a blend ratio of 2: 2: 1 was added as a light stabilizer in an amount of 0.2 part by weight, and lard was added in an amount of 0.5 part by weight.

Comparative Example 13 is a polyurethane V-ribbed belt 200-J- made of a polyurethane having no light-resistant stabilizer and no fat or oil and having a cross-sectional shape shown in FIG.
No. 4 belt was used. Comparative Example 14 consisted of 100 parts by weight of polyurethane and 2 parts by weight of a light-resistant stabilizer of a mixture of a benzotriazole-based ultraviolet absorber and a hindered phenol-based antioxidant in a blend ratio of 1: 1. Polyurethane V-ribbed belt 200
The belt of -J-4 was used. At this time, 7 parts by weight of lard was added as an oil or fat to 100 parts by weight of polyurethane. As Comparative Example 15, a mixture of 100 parts by weight of polyurethane and a blend ratio of a benzotriazole-based UV absorber, a hindered amine-based UV stabilizer and a hindered phenol-based antioxidant in a ratio of 2: 2: 1 was light-stable. A polyurethane V-ribbed belt 200-J-4 made of one added with 0.1 part by weight as an agent was used. At this time, 7 parts by weight of lard was added as an oil or fat to 100 parts by weight of the polyurethane. Comparative Example 16: 100 parts by weight of polyurethane, the curing agent of the example, and 100 parts by weight of polyurethane as a light stabilizer. Blend ratio of benzotriazole-based ultraviolet absorber, hindered amine-based ultraviolet stabilizer and hindered phenol-based antioxidant to 100 parts by weight of polyurethane. Is 2:
A mixture of 2: 1 and 2 parts by weight of a light stabilizer was used. At this time, no fat was added.

The above Examples 9 and 10 and Comparative Examples 13 to
An accelerated discoloration test (Sakashine test) was performed on 15 belts. Accelerated discoloration test (sunshine test)
Used a sunshine carbon weather meter, and the temperature condition was 63 ± 3 ° C. The discoloration determination method uses a Hunter color difference equation, and the measured values are L, a, b, ΔL, Δa,
Using L, a, and b of the sample before the sunshine test as reference values for Δb and ΔE (H), the value of the color difference ΔE (H) was graphed. FIG. 12 shows the result.

In Comparative Example 13 in which nothing was added, discoloration occurred at a rate 12 times or more that in Example 1 in which 2 parts by weight of the light stabilizer was added. Further, at the discoloration convergence point, the degree of discoloration in Comparative Example 13 was doubled as compared with Example 9. Further, the degree of discoloration of Examples 9 and 10 is considerably smaller than that of Comparative Examples 14 and 15. Therefore, in order to sufficiently prevent discoloration, it is necessary to add 0.2 parts by weight of a light-resistant stabilizer to 100 parts by weight of polyurethane, and it is necessary to add a benzotriazole-based ultraviolet absorber, a hindered amine-based ultraviolet stabilizer, and a hindered amine. It consists of three components of a dophenol-based antioxidant, and it is essential to add three components of a benzotriazole-based ultraviolet absorber.

Next, as Example 11, polyurethane V
As a blend of the belt, 100 parts by weight of a polyether-based urethane prepolymer was used as a curing agent for 3,3'-dichloro-
4,4'-diaminodiphenylmethane and 100 parts by weight of polyurethane as a light stabilizer, a benzotriazole-based UV absorber, a hindered amine-based UV stabilizer, a hindered phenol-based UV absorber and a hindered phenol-based antioxidant A polyurethane V-belt comprising 2 parts by weight of a mixture mixed at a blend ratio of 2: 2: 1 as a light-resistant stabilizer and 7 parts by weight of lard as an oil or fat was used. At this time, as the polyurethane V belt, a polymax belt 5M-90 was used.
0 was used. This belt has a belt length of 900 mm,
The belt shape was a 5M polymax belt. As shown in FIG. 7, the polymax belt 5M is a belt having a belt width a of 5 mm and a belt thickness b of 3 mm as cross-sectional dimensions. As Example 12, 100 parts by weight of the prepolymer of Example 11 and 100 parts by weight of polyurethane as the curing agent and light stabilizer of Example 10 were used as a benzotriazole-based ultraviolet absorber, a hindered amine-based ultraviolet stabilizer, and a hindered phenol-based compound. A mixture of antioxidants at a blend ratio of 2: 2: 1 was added as a light stabilizer in an amount of 0.2 part by weight, and lard was added in an amount of 0.5 part by weight.

As Comparative Example 17, a polymax belt 5M-900 consisting only of a polyurethane to which no light stabilizer and no oil was added was used. Comparative Example 18: 100 parts by weight of polyurethane, 100 parts by weight of polyurethane as a light stabilizer, 100 parts by weight of polyurethane, 100 parts by weight of polyurethane, blend ratio of benzotriazole-based UV absorber, hindered amine-based UV stabilizer and hindered phenol-based antioxidant Is 2:
A mixture of 2: 1 and 2 parts by weight of a light stabilizer was used. At this time, no fat was added.

Then, a sound test was performed using a bench running test machine. The test conditions were as follows: the pulley was a 5M-shaped pulley having a V-groove formed thereon, the driving pulley diameter was 25.6 mm, the driven pulley diameter was 128 mm, the load applied to the belt was 170 W, and the belt initial tension was 25 pounds. The rotation speed of the driving pulley was 1,797 rpm. Then, the sound was measured by a normal sound level meter at a distance of 20 mm from the drive pulley. The results are shown in Table 4 and FIG.

[0056]

[Table 4]

As is clear from Table 4 and FIG. 13, the belt in which 7 parts by weight of lard was added to 100 parts by weight of polyurethane was 9 dB in comparison with Comparative Example 18, and Comparative Example 17
The sound pressure is reduced by about 13 dB as compared with the above. In the human ear, a change in sound intensity is recognized when the sound pressure changes by 10% when the sound pressure level is 70 dB or more. In Example 11, the difference is clearly recognized because it is lower than Comparative Examples 18 and 17 by 9 dB or more. Therefore, Example 1
1 is considered to be sufficiently quieter than the comparative example. Comparative Example 17 and Comparative Example 1 were obtained by adding 0.5 parts by weight of lard to 100 parts by weight of polyurethane.
Although the sound pressure is lower than that of Example 8, it is closer to Comparative Examples 17 and 18 than Example 11, and when the amount of lard added is smaller than this, it is almost the same as the state where lard is not added. You can see that.

Further, an abrasion resistance test was conducted under the same conditions as those used for measuring the sound pressure with the same testing machine. Figure 1 shows the results.
It is shown in FIG. According to this, after running for 100 hours, the belt of Example 11 had a wear amount of 0.4% and the belt of Comparative Example 17 in which neither the light stabilizer nor the oil or fat was added had a wear amount of 0.4%.
It is 7%, which indicates that the addition of fats and oils improves the abrasion resistance.

Further, as Example 13, a polymax belt 11M-800 was produced with the same composition as in Example 11.
This belt has a belt length of 800 mm and a belt shape of 1
It was a 1M polymax belt. The polymax belt 11M has a larger cross-sectional dimension than 5M, and is a belt having a belt width a of 11 mm and a belt thickness b of 7 mm as shown in FIG. 6 and having a larger transmission capacity than 5M. Further, as Comparative Example 19, a polymax belt 11M-800 was prepared by adding lard as an oil and fat to 10 parts by weight of a polyurethane without adding a light stabilizer to 100 parts by weight of polyurethane. As Comparative Example 20, with the same composition as Comparative Example 18,
Polymax belt 11M-800 was produced.

Using the above-mentioned belt, the relationship between the running time and the slip ratio of the belt was measured by a bench tester. As test conditions, three pulleys having a diameter of 67 mm were used in a three-axis test machine. Then, the pulley was rotated at 5000 revolutions per minute, and 5.8 horsepower was applied as a load. At this time, the initial tension of the belt was 56 pounds. The result is shown in FIG.

The belt of Example 13 in which 7 parts by weight of lard was added as an oil and fat to 100 parts by weight of polyurethane and the belt of Comparative Example 20 in which lard was not added at all had a slip ratio even after 100 hours of running time. It can be seen that the belt function is not decreasing and the function of the belt is not decreased. However, the belt in which 10 parts by weight of lard is added to 100 parts by weight of polyurethane has a running time of about 70 hours and the slip ratio is already 4%.
It can be seen that the slip ratio tends to increase, and if the vehicle runs further, the predetermined transmission force cannot be transmitted.

[0062]

As described above, according to the first aspect of the present invention, in a belt made of a polyurethane elastic body in which a core wire is embedded in the belt body along the longitudinal direction, oil and fat are contained in the polyurethane elastic body. It is a polyurethane belt added. According to the first aspect of the present invention, the addition of fats and oils to the polyurethane elastic body has an effect of suppressing sound generation at the time of engagement between the belt and the pulley.

According to the second aspect of the present invention, since the fat or oil is lard, the lard precipitates on the belt surface, thereby lowering the friction coefficient of the belt surface, and the engagement between the belt and the pulley or the pulley alignment is incorrect. In this case, the generation of sound can be further suppressed.

According to the third aspect of the present invention, by using a polyurethane belt in which 0.5 to 7 parts by weight of fats and oils are added to 100 parts by weight of polyurethanes, an appropriate amount of fats and oils is used, so that a polyurethane elastic material is used. This has the effect of sufficiently suppressing the generation of sound without lowering the physical properties. Further, even with a belt requiring a high transmission force, sufficient power can be transmitted without slipping.

According to the invention described in claim 4, the effect of preventing discoloration can be sufficiently obtained by using a light-resistant stabilizer having a limited amount of each component and adding fats and oils to polyurethane.
It also has the effect of suppressing the generation of sound.

According to the fifth aspect of the present invention, since the polyurethane belt is a toothed belt, a tapping sound at the time of engagement between the belt and the pulley, and a "squeaking" sound caused by a high friction coefficient of the polyurethane. Can be prevented.

According to the invention described in claim 6, the polyurethane belt is a friction transmission belt in which at least one V-shaped protrusion or V rib extending in the belt circumferential direction is formed integrally with the main body. By adding fats and oils, it is possible to prevent the "prickling" sound when the pulley arration is out of order, and because the belt does not stick to the pulley because the friction coefficient of the belt is low, it can be pronounced Absent.

[Brief description of the drawings]

FIG. 1 is a toothed belt made of polyurethane of the present invention,
(A) is a partially broken perspective view, and (b) is a sectional view.

FIG. 2 is a polyurethane toothed belt for a bicycle according to the present invention, wherein (a) is a partially cutaway perspective view and (b) is a sectional view.

FIG. 3 is a perspective view of a polyurethane V-belt of the present invention.

FIG. 4 is a perspective view of a polyurethane V-ribbed belt of the present invention.

FIG. 5 is a perspective view of a polyurethane truncated V-ribbed belt of the present invention.

FIG. 6 is a sectional view of a polyurethane V-ribbed belt of the present invention.

FIG. 7 is a sectional view of a polyurethane V-belt of the present invention.

FIG. 8 is a graph in which the color difference (ΔE) is plotted against the sunshine time in the toothed belt of the present invention.

FIG. 9 is a schematic view of a sounding tester for a toothed belt using an actual facsimile motor.

FIG. 10 is a schematic diagram of a pronunciation tester using an actual bicycle.

FIG. 11 is a graph of a sounding state of an example and a comparative example when a sounding test is performed on an actual bicycle device.

FIG. 12 is a graph in which the color difference (ΔE) is plotted against the sunshine time in the V-ribbed belt of the present invention.

FIG. 13 is a graph of the sounding status of the example and the comparative example when a sound test of a polymax belt is performed by a bench tester.

FIG. 14 is a graph of a wear resistance test of a polymax belt on a bench tester.

FIG. 15 is a graph showing a relationship between a running time of a polymax belt on a bench tester and a slip ratio.

[Description of Signs] 1 Polyurethane toothed belt 2 Back part 3 Core wire 4 Canvas 5 Teeth 6 Teeth bottom 7 Bicycle polyurethane toothed belt 8 Polyurethane V belt 9 V-shaped protrusion 10 Back cog 11 Polyurethane V Ribbed belt 12 polyurethane truncated V-ribbed belt 13 pronunciation tester 14 drive pulley 15 driven pulley 16 PM driver 17 pulse oscillator 18 handle for adjusting the distance between axes 19 ordinary noise meter 20 LM guide 21 hybrid type stepping motor 22 bicycle belt sound tester 23 Drive Pulley 24 Follower Pulley 25 Stethoscope 26 Timing Belt 27 Motor 28 Roll 30 Powder Brake 31 Rear Wheel 32 Bicycle Support Rod 34 Testing Machine Base

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shiro Fukuda 4-1-1-21 Hamazoedori, Nagata-ku, Kobe City, Hyogo Prefecture Inside Mitsuboshi Belting Co., Ltd.

Claims (6)

[Claims] 1. A belt made of a polyurethane elastic body having a cord embedded in a belt body along a longitudinal direction,
A polyurethane belt obtained by adding fats and oils to the polyurethane elastic body. 2. The polyurethane belt according to claim 1, wherein said fat is lard. 3. The polyurethane belt according to claim 1, wherein 0.5 to 7 parts by weight of an oil or fat is added to 100 parts by weight of the polyurethane. 4. At least 0.08 of a benzotriazole-based ultraviolet absorber is added to 100 parts by weight of the polyurethane.
To 1.6 parts by weight, 0.08 to 1.6 parts by weight of a hindered amine ultraviolet stabilizer and 0.04 to 0.8 parts by weight of a hindered phenolic antioxidant were added. The polyurethane belt according to claim 1. 5. The belt according to claim 1, wherein the belt is a toothed belt in which teeth and grooves are alternately formed at a constant pitch inside the belt, and a tensile member is embedded at a pitch line position. Polyurethane belt. 6. The polyurethane belt according to claim 1, wherein the belt is a friction transmission belt in which at least one V-shaped protrusion or V rib extending in a belt circumferential direction is formed integrally with a main body.