JP3474695B2 - Conveyor belt - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conveyor belt, and more particularly to a vending machine, a public telephone, an automatic teller machine,
The present invention relates to a device suitable for use outdoors.

[0002]

2. Description of the Related Art Generally, a conveyor belt is used to convey bills and coins in an automatic vending machine, a communication card in a card-type public telephone, a card in an automatic teller machine, and the like in respective devices. At that time, since many of these devices are installed outdoors, the conveyor belt can obtain a stable coefficient of friction even if the external environment such as temperature, rainwater, or oil changes. It is required that the transported object can always be transported reliably.

Therefore, in the prior art, for example, Japanese Patent Laid-Open No. 4-20
As described in Japanese Patent No. 9114, at least the rubber layer on the conveying surface side is composed of a composition in which short fibers such as aramid, vinylon, polyester, polypropylene and nylon are added to matrix rubber such as urethane rubber. As a result, a stable friction coefficient can be obtained even if the rainwater adheres. In particular, since the millable urethane rubber has a high friction coefficient, it is said that it is suitable as a matrix rubber of a vulcanized rubber composition constituting a conveyor belt.

[0004]

However, in the above-mentioned conventional conveyor belt, since the friction coefficient is largely reduced when rainwater or oil adheres, the outdoor conveyor belt is easily affected by such a change in external environment. However, there is a problem that it is difficult to stably maintain the belt conveying ability when used in.

On the other hand, among the environmental changes in the outdoors, temperature changes are one of the factors that have a great influence on the flexibility of the conveyor belt, but the hardness of the rubber rises and the flexibility of the belt is lost especially at low temperatures. Since it is easy, the belt starting torque and loss torque in each device are large, which
There is also a problem that it is a bottleneck in improving the operational stability of the device itself.

The present invention has been made in view of the above points, and its main purpose is to focus on millable urethane rubber, which is said to be capable of exhibiting a high friction coefficient, and to consider the friction characteristics and hardness characteristics of the polyol component. By clarifying the difference, it is possible to suppress the reduction of the friction coefficient even when affected by rainwater or oil, while maintaining the flexibility of the belt at low temperatures, so that it can be used outdoors. It is intended to be able to stably maintain the belt conveyance ability in an apparatus such as a vending machine used, and to contribute to the improvement of operation stability of the apparatus itself.

[0007]

In order to achieve the above-mentioned object, in the present invention, the case where the polyol component of the millable urethane rubber is a polyester polyol (first composition) and the case where it is a polyether polyol ( The second composition) is based on the finding that the friction characteristics and the hardness characteristics conflict with each other. On top of that, the conveyor belt has a two-layer structure consisting of a main rubber layer and a back rubber layer,
The backside rubber layer, which requires belt conveyance ability, is composed of the first composition, which has a small decrease in the friction coefficient due to the influence of water and oil, and the main rubber layer, which influences the belt flexibility, is excellent in low-temperature flexibility. Each of the second compositions was used.

Specifically, in the invention of claim 1, the main body rubber layer and the back surface rubber layer provided on the conveying surface side of the main body rubber layer are provided, and the back surface rubber layer is opposite to the main body rubber layer. It is premised that the side surface is a conveyance surface, and that the conveyance belt contacts the conveyance surface to convey the object. The back rubber layer is made of a first composition containing a millable urethane rubber having a polyol component of polyester polyol as a matrix rubber. On the other hand, the main body rubber layer is made of a second composition containing a millable urethane rubber having a polyol component of polyether polyol as a matrix rubber. In the above configuration, the millable urethane rubber (first composition) in which the polyol component is a polyester polyol is as high as the millable urethane rubber (second composition) in which the polyol component is a polyether polyol. It has a coefficient of friction, but the decrease in coefficient of friction when water or oil adheres is small. Therefore, by providing the back rubber layer made of the first composition, a high friction coefficient can be stably ensured in an environment where water or oil is likely to adhere to the transport surface, and thus excellent belt transport capability is exhibited. . However, since the millable urethane rubber of the first composition has a relatively high glass transition temperature, if the entire belt is made of the millable urethane, the hardness of the rubber is suppressed from increasing at low temperatures and the flexibility of the belt is maintained. It does not meet the purpose of doing. Therefore, while the backside rubber layer is composed of the first composition, the backside rubber layer can be easily vulcanized and adhered to the backside rubber layer, and the glass transition is more than that of the millable urethane rubber of the first composition. By forming the main rubber layer from the second composition made of millable urethane having a low temperature, the flexibility of the belt at low temperature can be maintained.

According to a second aspect of the present invention, in the first aspect of the present invention, the first composition comprises matrix rubber to which phenol short fibers are added. Furthermore, it is assumed that a part of the above-mentioned short phenol fibers is exposed on the conveying surface. In the above composition, the first composition constituting the back rubber layer of the conveyor belt contains phenol short fibers having a high friction coefficient as a friction coefficient control material, and a part of the phenol short fibers is exposed on the surface as the belt conveyor surface. Therefore, the phenol short fibers can increase the friction coefficient of the surface of the first composition, that is, the transport surface. Therefore, in combination with the excellent frictional properties of the millable urethane rubber of the first composition, the carrying ability of the carrying belt can be further improved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a conveyor belt according to an embodiment of the present invention. The conveyor belt is basically a flat belt, and for example, a belt for conveying banknotes and coins in an automatic vending machine, a call card conveyor for a card type telephone. It is used as a belt for, and as a belt for carrying cards in automatic teller machines.

The above-mentioned conveyor belt has a belt length direction (see FIG. 1).
A main body rubber layer 1 in which a core body 2 is embedded so as to extend in the left-right direction) and a back surface rubber layer 3 laminated on the belt back surface side (upper surface side in the figure) of the main body rubber layer 1. The core body 2 is made of a fiber material such as nylon and secures the tensile strength of the conveyor belt.

The main rubber layer 1 constitutes the main body of the conveyor belt and is made of a predetermined vulcanized rubber composition. On the other hand, the back rubber layer 3 is also made of a vulcanized rubber composition, and the outer peripheral surface of the belt on the side opposite to the main rubber layer 1 (the upper surface side in FIG. 1) is a conveying surface 4, and on the conveying surface 4. A bill, a coin, a card, etc. are brought into contact with each other and are conveyed by a frictional force between them.

The first rubber forming the back rubber layer 3
In the vulcanized rubber composition, the millable urethane rubber containing polyester polyol as the polyol component is used as the matrix rubber 5. On the other hand, in the second vulcanized rubber composition forming the main rubber layer 1, as the matrix rubber 5, a millable urethane rubber containing polyether polyol as a polyol component is used. That is, both matrix rubbers 5 are millable urethane rubbers, but their polyol components are different from each other, and the polyol component of the first vulcanized rubber composition is polyester polyol, whereas the second vulcanized rubber composition is the second vulcanized rubber composition. The polyol component of the rubber composition is a polyether polyol.

Here, the frictional characteristics and low temperature flexibility of the two millable urethane rubbers will be described. The millable urethane rubber of the first vulcanized rubber composition is the millable urethane rubber of the second vulcanized rubber composition. Compared with rubber, it has the same high friction coefficient, but the decrease in friction coefficient when water or oil adheres is small.

However, since the millable urethane rubber of the first composition has a relatively high glass transition temperature, if the entire belt is made of the millable urethane,
It does not meet the purpose of suppressing the increase in rubber hardness at low temperatures and maintaining the flexibility of the belt. Therefore, while the backside rubber layer 3 is composed of the first composition, it can be easily vulcanized and bonded to the backside rubber layer 3 without an adhesive, and has a glass transition temperature higher than that of the millable urethane rubber of the first composition. The main rubber layer 1 is made of the above-mentioned second composition which is made of millable urethane having a low viscosity.

In each of the above rubber compositions, a reinforcing agent such as carbon black, silica, calcium carbonate, talc,
The inorganic filler such as clay can be arbitrarily selected. Further, the above rubber composition may be blended with an extender oil for rubber, a chemical agent for rubber, and an additive for rubber, if necessary. As the extender oil for rubber, aromatic, naphthenic and paraffinic oils are preferable. Further, as chemicals for rubber and additives for rubber, crosslinking agents such as sulfur and peroxide, vulcanization accelerators such as zinc white and stearic acid, and antioxidants such as amine-based, phenol-based, sulfur-based and phosphorus-based antioxidants Or other than antioxidant,
An ultraviolet absorber, an ozone deterioration inhibitor, a tackifier, a plasticizer, etc. are used.

In addition, in the first vulcanized rubber composition constituting the back rubber layer 3, the matrix rubber 5 is
A part of the short fiber 6 as a friction coefficient control material is the transport surface 4
Is added so that it is exposed on the surface of. Also, FIG.
In the example shown in (1), it is oriented in a direction orthogonal to the transport surface 4. The short fiber 6 has a fiber length of 10 mm or less,
Further, the ratio of the fiber length to the fiber diameter is 40 or more, and the phenol short fiber having a large friction coefficient (for example, "Kynol KF02BT (trade name)" which is a phenol resin short fiber manufactured by Nippon Kynol Co., Ltd.), Kynol KF
0206 (trade name) "," Kynol KF05BT (trade name) ", etc. are used. The mixing amount of the phenol short fibers 6 is not particularly limited, but from the viewpoint of stabilizing the friction coefficient and ensuring processability, it is 1.5 to 30% by volume.
Is desirable.

The manufacturing process of the conveyor belt configured as described above is the same as the conventional process. For example, first, the main rubber layer 1
When forming, the raw material is kneaded in a predetermined mixing ratio, and the main body rubber sheet is formed by calendering or the like. On the other hand, when the back rubber layer 3 is formed, the raw materials are kneaded in a predetermined mixing ratio, the phenol short fibers 6 are mixed in the kneading, and the kneaded product in which the short fibers 6 are mixed is calendered or extruded. Etc. to form the back rubber sheet. Next, the obtained main body rubber sheet is wound around a cylindrical belt forming die, the core body 2 is arranged on the outer periphery of the die, and the back rubber sheet is wrapped around, and both rubber sheets are integrated by vulcanization. . The back surface of the belt thus formed is buffed to expose the short fibers 6 from the surface of the rear transport surface 4. The conveyor belt is manufactured as described above.

Therefore, in this embodiment, the matrix rubber 5 in the first vulcanized rubber composition is a millable urethane rubber containing a polyester polyol as a polyol component and has a high friction coefficient, and particularly as an influence from the external environment. When oil or water adheres, the friction coefficient decreases less than in the case of millable urethane rubber (second vulcanized rubber composition) that uses polyether polyol as the polyol component, so a high friction coefficient is secured stably. As a result, the belt conveyance ability can be maintained. Therefore, by providing the back rubber layer 3 made of the first composition, a high friction coefficient can be stably secured even in an environment in which water or oil is likely to adhere to the transport surface 4, so that excellent belt transport is possible. You can exercise your ability.

Further, the second vulcanized rubber composition constituting the main rubber layer 1 is a millable urethane rubber containing a polyether polyol as a polyol component,
Since the glass transition temperature is lower than that of the vulcanized rubber composition, it is possible to maintain the flexibility of the belt at low temperature, and to suppress the increase of the starting torque and the loss torque due to the reduction of the flexibility.

Moreover, since phenolic short fibers 6 having a high friction coefficient are added to the rear rubber layer 3 as a friction coefficient controlling material and a part of the phenol short fibers 6 is exposed on the surface of the conveying surface 4, the above short fibers are used. 6 makes it possible to further increase the friction coefficient of the backside rubber layer 3 and greatly improve the conveyance ability of the belt, and to reduce the friction coefficient of the conveyance surface 4 against factors such as rainwater and oil adhesion that lower the friction coefficient. The decrease in the coefficient is further reduced, and the belt carrying capacity can be maintained at a high level.

That is, the transport belt having such a structure is used as a transport belt for bills and coins in an automatic vending machine, a transport belt for a call card in a public telephone, and a card transport belt for an automated teller machine. Therefore, even if these devices are installed outdoors, etc., and even if the transportation conditions change due to external factors such as rainwater or oil adhesion, the transported object can be transported stably and at low temperature conditions. It is possible to suppress an increase in the starting torque and the loss torque in the. Therefore, it is possible to contribute to the operational stability of the vending machine, public telephone, and automatic teller machine.

In the above embodiment, the short fibers 6 are oriented perpendicular to the transport surface 4, but the orientation is particularly limited depending on the usage conditions such as the friction coefficient required for the transport surface 4. Not something.

In the above embodiment, the conveyor belt is a flat belt, but it may be a belt having another structure such as a toothed belt.

Further, in the above embodiment, the vending machine,
Although the case of a telephone and an automatic teller machine has been described, the invention can be applied to a conveyor belt installed in other devices.

[0026]

EXAMPLES Next, specific examples of each rubber composition forming the main rubber and the back rubber layer in the above-mentioned conveyor belt will be described.

A millable urethane rubber whose polyol component is a polyester polyol ("Mirasen 76 (trade name)" manufactured by TSE USA) and a millable urethane rubber whose polyol component is a polyether polyol ("Mirasen E-34 (trade name)") (Made by the same company) are used as the rubber material of the rubber composition, and the reinforcing agent, the filler, the additive, etc. having the composition shown in the following Table 1 are added at respective compounding ratios (weight ratios) and kneaded with a 3l kneader. Then, after sheeting with a roll and press vulcanizing into a sheet having a thickness of 2 mm, the width is 6.4 mm, the length is 60 mm and the thickness is 2 mm.
3 types of samples were prepared. In addition, Table 1 above
"Curasen (trade name)" (manufactured by TSE in the United States)
It is a partial complex of zinc chloride and a vulcanization accelerator DM.

[0028]

[Table 1]

Then, the above-mentioned three kinds of samples were used as composition A
(Polyester polyol + phenol short fiber), composition B (polyether polyol + phenol short fiber),
And Composition C (polyether polyol + phenol short fiber not added). Separately from the sample of the sheet having a thickness of 2 mm, each of the compositions A to C was press-vulcanized into a sheet having a thickness of 1 mm, and the width was 5.0 mm and the length was 5 mm.
Three types of samples having a thickness of 0 mm and a thickness of 1 mm were prepared.

That is, the composition A constitutes the first composition in the present invention, in which a millable urethane rubber containing polyester polyol as a polyol component is used as a matrix rubber, and a phenol short fiber is used as a friction coefficient controlling material. Is added. The composition B is a mixture of millable urethane rubber containing polyether polyol as a polyol component and matrix phenol added with phenol short fibers. The composition C is the same as the composition B to which the phenol short fibers are not added, and constitutes the second composition of the present invention. With respect to each sample of the compositions A and B, after the press vulcanization, the surface of each sheet was polished to expose a part of the phenol short fibers.

Then, the friction coefficient of each surface of the compositions A and B was measured with a Haydon surface property tester Model 14 using the sample having the thickness of 2 mm. As the conditions for measuring the coefficient of friction by the Haydon tester, as shown in FIG. 2, the object to be conveyed conveyed by the conveyor belt is a telephone card 11 for public telephone (6.4 mm width × 60 mm).
(Length × 2 mm thickness), the card 11 was horizontally arranged and fixed, and the sample 12 was placed thereon, and a vertical load W of 100 g was applied from above to bring the sample 12 into close contact with the card 11.
The frictional force F when the sample 12 was pulled and moved in the horizontal direction at a speed of 100 mm / min in that state was measured, and the frictional coefficient (normal frictional coefficient) at that time was obtained by the following formula.

Friction coefficient = F / 100 Further, water and a lubricant were respectively applied to the upper surface of the card 11, and the friction coefficients (water-applied friction coefficient and lubricant-applied friction coefficient) were determined in the same manner as above. As the lubricant, "CRC5-56 (trade name)" manufactured by Kure Kogyo Co., Ltd. was used.
The friction coefficient of each sample is also shown in Table 2 below.

[0033]

[Table 2]

When the friction coefficient of each sample shown in Table 2 above is compared and considered, the friction coefficient of the composition A is kept larger than that of the composition B even when water or a lubricant is applied. And that the rate of change from the normal friction coefficient is small. Therefore, since the back rubber layer is composed of the composition A, the friction characteristics are stable against the external environment such as oil and water, and the friction coefficient is high, so that the conveyance ability and the stability are excellent. A conveyor belt will be obtained.

Next, the composition A containing the above-mentioned thickness of 1 mm
Using each sample of C, the dynamic storage elastic modulus E ′ and the glass transition temperature when the atmospheric temperature was 25 ° C. and −30 ° C. were measured using a rheometer RSA-II manufactured by Rheometrics. The glass transition point was the peak temperature in the temperature dispersion of the loss tangent tan δ. The measurement condition was a frequency of 10 Hz. The measurement results are also shown in Table 3 below.

[0036]

[Table 3]

According to Table 3 above, compositions B and C have lower glass transition temperatures than composition A,
Also, it can be seen that the elastic modulus at low temperature is small. Therefore,
When the belt is composed of the compositions B and C, a belt excellent in low temperature flexibility can be obtained.

That is, as shown in Table 4 below, in the invention examples in which the back rubber layer was composed of the composition A and the main rubber layer was composed of the composition C, both the back rubber layer and the main rubber layer were composed. Compared with Comparative Example 1 composed of the material A and Comparative Example 2 in which the backside rubber layer and the main rubber layer are both composed of the composition B, it is possible to have excellent performances in both conveyance ability and low temperature flexibility. I understand. In the table, “⊚” indicates excellent, “∘” indicates good, and “x” indicates not.

[0039]

[Table 4]

[0040]

As described above, according to the first aspect of the invention, the rear rubber layer of the conveyor belt has a high coefficient of friction and has a high friction coefficient even when water or oil adheres to the rear rubber layer of the conveyor belt. On the other hand, the main rubber layer of the conveyor belt is made of a polyether polyol as the polyol component and has a low glass transition temperature and a low glass transition temperature. Since it is composed of a second composition that uses a millable urethane rubber that can maintain the belt flexibility at times as a matrix rubber, it can exhibit excellent transporting ability even when rainwater, oil, etc. adhere to it, while at a low temperature. It is possible to reduce the belt starting torque and loss torque at the time of operation, and to operate devices such as vending machines installed in such an external environment. It can contribute to the stabilization of.

According to the second aspect of the present invention, the first composition is formed by adding a phenol short fiber as a friction control material to the matrix rubber, and a part of the phenol short fiber is exposed on the conveying surface. By doing so, in combination with the excellent frictional properties of the millable urethane rubber of the first composition, the carrying capacity of the carrying belt can be further improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view schematically showing a part of a conveyor belt according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an outline of a friction coefficient measurement test.

[Explanation of symbols]

1 Body rubber layer 2 body 3 Back rubber layer 4 Transport surface 5 Matrix rubber 6 Phenol short fiber

Claims (2)

(57) [Claims] 1. A body rubber layer and a back rubber layer provided on the back side of the body rubber layer, wherein the surface of the back rubber layer opposite to the body rubber layer is a carrying surface, and the carrying A conveyor belt configured to convey an object to be conveyed by contacting the surface thereof, wherein the back rubber layer is composed of a first composition containing a millable urethane rubber whose polyol component is polyester polyol as a matrix rubber, The main body rubber layer is a conveyor belt comprising a second composition having a millable urethane rubber whose polyol component is a polyether polyol as a matrix rubber. 2. The conveyor belt according to claim 1, wherein the first composition is formed by adding a phenol short fiber to a matrix rubber, and a part of the phenol short fiber is exposed on a transport surface. Conveyor belt characterized by having.