WO2016190350A1

WO2016190350A1 - Conveyor belt for paper sheets

Info

Publication number: WO2016190350A1
Application number: PCT/JP2016/065445
Authority: WO
Inventors: 秀久川村; 学山崎; 将史城尾; 彰竹中; 謙介齊藤
Original assignee: ニッタ株式会社
Priority date: 2015-05-25
Filing date: 2016-05-25
Publication date: 2016-12-01
Also published as: JP2016216239A

Abstract

Provided is a conveyor belt for paper sheets, which is characterized by being provided with: a core layer (12) that contains a polyurethane-based thermoplastic elastomer; a rubber layer (14) that is provided on one surface (12a) of the core layer (12); and a conductive resin layer (16) that is provided on the other surface (12b) of the core layer (12). This conveyor belt for paper sheets has a high tension at elongation and excellent tear resistance.

Description

Paper sheet conveyor belt

The present invention relates to a paper sheet conveying belt, particularly a mail sorting machine belt.

The endless belt is used as a paper sheet conveying belt for conveying paper sheets such as banknotes and tickets (see Patent Document 1). In Patent Document 1, the shape of the belt is maintained by a shape-retaining rubber layer, and a surface layer made of a thermoplastic elastomer is provided on the conveying surface in place of the conventional seamless woven fabric layer to prevent meandering of the endless belt. To improve the driving performance. It is described that the shape-retaining rubber layer further has a function of maintaining the tension of the belt.

In Patent Document 1, a polyamide-based thermoplastic elastomer is recommended as the thermoplastic elastomer constituting the surface layer. According to Patent Document 1, the friction coefficient can be reduced by using a polyamide-based thermoplastic elastomer for the surface layer, and the slack of the belt due to the difference in the winding length around the direction change guide pulley can be reliably prevented. Thereby, conveyance is performed smoothly. In addition, changes in the wear resistance and friction coefficient with time are reduced, and the running performance of the belt is further stabilized.

JP-A-6-144626

The conveying belt may be stretched by receiving a tensile load during use in the paper sheet conveying apparatus. In order to limit the elongation of the conveying belt when subjected to a tensile load, it is desirable that the paper sheet conveying belt has a large tension at the time of extension (for example, a tension at 5% elongation).

Also, in the paper sheet transport apparatus, paper sheets being transported by the transport belt may be jammed in the transport path. Paper jams cause tearing of the conveyor belt. When the conveyance belt has poor tear resistance, vertical cracks occur even during short-term operation, and the conveyance belt needs to be replaced.

In a mail sorting machine among paper sheet transport apparatuses, the transport belt is often twisted to change the direction of the top of the transported mail. Twisting also causes tearing of the conveying belt, so that the conveying belt is required to have sufficient tear resistance.

Therefore, an object of the present invention is to provide a paper sheet conveying belt having a large tension at the time of extension and excellent in tear resistance.

The paper sheet conveying belt according to the present invention is provided on a core layer containing a polyurethane-based thermoplastic elastomer, a rubber layer provided on one surface of the core layer, and on the other surface of the core layer. And a conductive resin layer.

According to the present invention, the core of the paper sheet conveying belt is made of a polyurethane-based thermoplastic elastomer. Since the polyurethane-based thermoplastic elastomer is less stretchable than other elastic materials, the paper sheet transport belt has a large tension at the time of extension. Moreover, since the core layer responsible for tear resistance is made of a polyurethane-based thermoplastic elastomer, the paper sheet conveying belt is also excellent in tear resistance.

It is sectional drawing of the paper sheet conveyance belt which concerns on this embodiment. 3 is a load-elongation curve obtained from a tensile test of a sample of a polyurethane-based thermoplastic elastomer. 3 is a load-elongation rate curve obtained from a tensile test of a belt of an example. It is a figure which shows the sample for a tear test. It is a graph which shows the result of a tear test.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1. 1 is a core layer 12, a rubber layer 14 provided on one surface 12a of the core layer 12, and a second surface 12b of the core layer 12. And a conductive resin layer 16.

<Core layer>
The core layer 12 occupies most of the thickness of the paper sheet conveying belt 10 and maintains the tension when the paper sheet conveying belt 10 is extended. Furthermore, the core body layer 12 bears the tear resistance of the paper sheet conveying belt 10. In order to fulfill such a function, the core layer 12 in the present embodiment is made of a polyurethane-based thermoplastic elastomer. The polyurethane-based thermoplastic elastomer is not particularly limited, and any polyurethane-based thermoplastic elastomer such as a polyester type, a polyether type, or a polycarbonate type can be used.

By forming the core layer 12 using a polyurethane-based thermoplastic elastomer having a higher hardness (JIS-A), the paper sheet conveying belt 10 having a higher tensile strength and tear resistance can be obtained. The polyurethane thermoplastic elastomer preferably has a hardness (JIS-A) of about 80 to 98 °, more preferably 90 to 98 °. The hardness of the polyurethane thermoplastic elastomer is determined according to JIS K6301.

The core body layer 12 may contain various additives such as pigments, antibacterial and antifungal agents, antioxidants, ultraviolet absorbers, and flame retardants as long as the effects of the present invention are not impaired.

The thickness t ₁ of the core body layer 12 can be appropriately set according to the thickness t ₀ and the configuration of the entire sheet transport belt 10, but the thickness t _{0 of the} entire sheet transport belt 10. It is preferably about 70 to 90%. For example, when the thickness t _{0 of the} entire sheet transport belt 10 is about 1.0 to 1.7 mm, the thickness t ₁ of the core layer 12 is about 0.9 to 1.2 mm. be able to.

<Rubber layer>
The rubber layer 14 is provided on the one surface 12 a of the core body layer 12 and serves as a conveyance surface layer of the paper sheet conveyance belt 10. Due to the presence of the rubber layer 14, it is possible to secure the conveyance force of the paper sheet with the friction coefficient of the conveyance surface within an appropriate range.

Rubber materials constituting the rubber layer 14 include natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, ethylene propylene rubber, chloroprene rubber, chlorinated polyethylene, epichlorohydrin rubber, nitrile rubber (NBR), acrylic rubber, urethane rubber, and the like. You can choose from. These rubber materials may be used alone or in combination of two or more. NBR is preferable as the rubber material because it can be fixed to the core layer 12 by a simple method and good adhesion can be obtained. When NBR is used, the friction coefficient of the surface of the rubber layer 14 against the conveyed paper sheet can be about 0.7 to 1.1.

Various additives such as pigments, flame retardants, and antibacterial / antifungal agents can be added to the rubber layer 14 as long as the effects of the present invention are not impaired.

The thickness t ₂ of the rubber layer 14 may be appropriately set according to the thickness t ₀ and configuration of the entire paper sheet transfer belt 10. For example, when the thickness t _{0 of the} entire sheet conveying belt 10 is about 1.0 to 1.7 mm, the thickness t ₂ of the rubber layer 14 is about 0.1 to 0.6 mm. Can do.

<Conductive resin layer>
The conductive resin layer 16 is provided on the other surface 12 b of the core body layer 12 and serves as a running surface layer of the paper sheet transport belt 10. The conductive resin layer 16 is composed of a conductive resin composition obtained by adding a conductivity imparting agent to a thermoplastic elastomer. The thermoplastic elastomer can be selected from polyurethane elastomers, polyester elastomers, polyamide elastomers, polyolefin elastomers, and the like. These thermoplastic elastomers may be used alone or in combination of two or more.

Examples of the conductivity-imparting agent include carbon-based conductivity imparting agents such as carbon black, graphite, and carbon fiber, and metal-based conductivity imparting agents such as fine powders of various metals such as copper, iron, and aluminum. . In general, when the conductivity imparting agent is contained in an amount of about 10% or more with respect to the thermoplastic elastomer, the conductivity is imparted and an antistatic effect is obtained.

The conductive resin layer 16 has a stabilizer, a stabilizing aid, an antioxidant, a light stabilizer, a nucleating agent, a lubricant, a flame retardant, a plasticizer, a pigment, and an antibacterial agent as long as the effects of the present invention are not impaired. Various additives such as a fungicide may be contained.

The thickness t ₃ of the conductive resin layer 16 can be set as appropriate according to the thickness t ₀ and the configuration of the entire sheet transport belt 10. For example, when the thickness t _{0 of the} entire sheet transport belt 10 is about 1.0 to 1.7 mm, the thickness t ₃ of the conductive resin layer 16 is about 0.03 to 0.1 mm. can do.

2. Manufacturing Method The paper sheet transport belt 10 is manufactured by any method as long as the core layer 12 and the rubber layer 14 and the core layer 12 and the conductive resin layer 16 are fixed and do not peel off. can do.

First, the core layer 12 is produced using a polyurethane-based thermoplastic elastomer. The core body layer 12 can be manufactured by using a predetermined raw material to prepare a sheet having a predetermined thickness by, for example, extrusion molding, and cutting the obtained sheet into a predetermined dimension.

The rubber layer 14 is prepared by applying a predetermined rubber material on the canvas by calendering or the like to produce a sheet-like rubber material, and transferring the obtained sheet-like rubber material to one surface 12 a of the core layer 12. Can be arranged.

The conductive resin layer 16 is prepared by applying a predetermined conductive resin composition onto a canvas by knife coating or the like to produce a sheet-like conductive resin composition. It can be transferred to the other surface 12 b of the core body layer 12 and arranged.

In transferring the rubber layer 14 and the conductive resin layer 16, a laminated body having a sheet-like rubber material and a sheet-like conductive resin composition disposed on each surface of the core body layer 12 and having a canvas on the outermost surface. obtain. The laminated body is squeezed and vulcanized under heat and pressure conditions to be processed into a predetermined thickness. The thickness after the press vulcanization can be set to, for example, about 1.0 to 1.7 mm. By compression vulcanization, the rubber layer 14 is fixed to one surface 12a of the core body layer 12 by vulcanization adhesion, and the conductive resin layer 16 is fixed to the other surface 12b of the core body layer 12 by vulcanization adhesion. The

The outermost canvas is peeled off, and the core layer 12, the rubber layer 14 provided on one surface 12a of the core layer 12, and the conductive resin layer 16 provided on the other surface 12b of the core body layer 12, Is obtained. The surface of the rubber layer 14 and the conductive resin layer 16 has irregularities due to the traces of the canvas.

The paper sheet transport belt 10 obtained in this way can have a desired size according to the apparatus to be applied. For example, the width can be about 10 to 400 mm, and the length can be about 400 to 100,000 mm. In the paper sheet conveying belt 10 of this embodiment, the rubber layer 14 side is used as a conveying surface, and the conductive resin layer 16 side is used as a running surface. The sheet conveying belt 10 of the present embodiment can be made endless by joining both ends with finger joints so that the rubber layer 14 becomes the conveying surface.

3. Action and Effect In the paper sheet conveying belt 10 according to the present embodiment, the core layer 12 is made of a polyurethane-based thermoplastic elastomer. Polyurethane thermoplastic elastomers are less prone to stretch than other elastic materials such as rubber and polyamide thermoplastic elastomers. Since such a polyurethane-based thermoplastic elastomer is used for the core body layer 12, the paper sheet conveying belt 10 according to the present embodiment has a high tensile tension.

Moreover, since the core layer 12 is made of a polyurethane-based thermoplastic elastomer, the paper sheet conveying belt 10 according to this embodiment also has improved tear resistance. For example, as compared with the case where a polyamide-based thermoplastic elastomer is used for the core layer, the paper sheet conveying belt 10 according to this embodiment has a tear strength improved by about twice.

The paper sheet conveying belt 10 according to the present embodiment has high tear resistance, so that occurrence of tearing due to paper sheet jamming or twisting of the belt itself is suppressed. As a result, it is possible to reduce the possibility of the belt being damaged in a short period.

As described above, since the polyurethane-based thermoplastic elastomer is difficult to stretch, the paper sheet conveying belt 10 according to this embodiment in which the core layer 12 is made of the polyurethane-based thermoplastic elastomer has a restoring force with respect to elongation of about 5%. Is expensive.

The paper sheet conveying belt 10 according to the present embodiment is particularly preferably used for a mail sorting machine in a paper sheet conveying apparatus.

4). Modifications The present invention is not limited to the embodiments described herein, and can be modified as appropriate within the scope of the gist of the present invention.

For example, in manufacturing the paper sheet transport belt 10, the rubber layer 14 and the conductive resin layer 16 are fixed to the core body layer 12 by vulcanization adhesion, but may be bonded using an adhesive. In order to adhere the rubber layer 14 to the core body layer 12, for example, a urethane-based adhesive can be used. In order to adhere the conductive resin layer 16 to the core body layer 12, for example, a urethane-based adhesive can be used. When bonding with an adhesive, the range of selection of the rubber used for the rubber layer 14 and the thermoplastic elastomer used for the conductive resin layer 16 is expanded. Prior to bonding, the rubber layer 14 and the conductive resin layer 16 can be vulcanized in advance.

Further, in making the paper sheet conveying belt 10 of the present embodiment endless, both ends of the belt are processed into a taper shape, the taper surfaces are bonded with an adhesive, and joined together by a sky bar joint. Good. For example, a urethane-based adhesive can be used as the adhesive.

5. Examples Hereinafter, although a flat belt will be described as an example and the paper sheet conveying belt of the present invention will be described in detail, the present invention is not limited to the following examples.

[Preliminary test]
Samples made of two types of polyurethane-based thermoplastic elastomers having different hardness (JIS-A) were prepared, and a tensile test was conducted according to JIS K7311 using a tensile tester (Shimadzu Corporation: AG2000B). Sample A (hardness 95 °) and sample B (hardness 85 °) were used as the polyurethane-based thermoplastic elastomer. The sample size was 20 mm wide, 500 mm long, and 0.8 mm thick.

In the tensile test, a load is applied until the sample breaks, and the elongation ((L ₁ −L ₀ ) / L ₀ × 100) is calculated using the initial length L ₀ and the length L ₁ at break. Asked. The load-elongation rate curve obtained from the test results is shown in FIG. In FIG. 2, curve A and curve B are the results for sample A and sample B, respectively. As shown in the graph of FIG. 2, the load of the sample A is about twice the load of the sample B when compared with the same expansion ratio. For example, the load when the stretch rate is 5% (5% stretch tension) is 1.1 N / mm for sample B, and 2.5 N / mm for sample A.

Among the polyurethane-based thermoplastic elastomers, those with high hardness have a higher tensile tension. By using such a material as a core layer that occupies most of the thickness of the belt, the tension at the time of extension as the belt can be further increased. Therefore, in the examples, a flat belt is produced using a polyurethane-based thermoplastic elastomer having a hardness of 95 ° as a material for the core layer.

[Example]
<Preparation of core layer>
A sheet having a thickness of 1.05 mm was produced by extrusion molding using the above-mentioned polyurethane-based thermoplastic elastomer having a hardness of 95 °. This sheet was cut into predetermined dimensions (width 400 mm, length 100000 mm) to obtain a core layer.

<Preparation of rubber layer>
NBR as a rubber material was applied to the canvas with a thickness of 0.25 mm by calendaring to obtain a sheet-like rubber material supported by the canvas.

<Preparation of conductive resin layer>
A conductive resin composition was prepared by adding a conductivity-imparting agent to the thermoplastic elastomer. The addition amount of the conductivity imparting agent was about 60 wt% with respect to the entire conductive resin composition. This conductive resin composition was applied to a canvas with a thickness of 0.15 mm by knife coating to obtain a sheet-like conductive resin composition supported on the canvas.

<Production of belt>
A sheet-like rubber material was placed on the surface of the core layer, and a sheet-like conductive resin composition was placed on the back surface to obtain a laminate having a canvas on the outermost surface. After pressing and vulcanizing this laminated body by a conventional method, the canvas was peeled from both surfaces to obtain a flat belt of an example having a thickness of 1.45 mm.

In the flat belt of the example, the rubber layer and the conductive resin layer are fixed to the front and back surfaces of the core layer made of a polyurethane thermoplastic elastomer having a thickness of 1.05 mm by vulcanization adhesion. The rubber layer has a thickness of 0.25 mm, and the conductive resin layer has a thickness of 0.15 mm. The surface of the rubber layer and the conductive resin layer had a concavo-convex pattern due to the traces of the peeled canvas.

<Tensile strength>
About the flat belt of the Example, the tension test was done like the above. FIG. 3 shows the load-elongation rate curve obtained from the test results by calculating the elongation rate in the same manner as described above. The flat belt of the example has a tension at 5% elongation of 2.37 N / mm.

<Tension at 5% extension>
Both ends of the flat belt of the example were joined by heat fusion to produce an endless belt having finger joints. After the obtained endless belt was mounted on an in-house manufactured testing machine and allowed to run for 200 hours, the tension at 5% elongation was 1.1 N / mm.

<Tear strength>
The flat belt of the example was cut into a width of 10 mm and a length of 60 mm to prepare three tear test samples. As shown in FIG. 4, the sample 20 was provided with a notch 22 of 30 mm along the longitudinal direction from the upper end.

In addition, three samples having the same dimensions were prepared using a commercially available belt having a thickness of 1.45 mm. The commercially available belt has a core layer made of a polyamide-based thermoplastic elastomer having a thickness of 0.75 mm, an NBR layer having a thickness of 0.35 mm that covers the surface of the core layer, and a thickness that covers the back surface of the core layer. It is composed of a 0.35 mm NBR layer.

These samples were measured for tear strength using a tensile tester (Shimadzu Corporation: AG2000B). Specifically, the two

end portions

24a and 24b divided by the notch 22 of the sample 20 were each tightened with a gripping tool, and the gripping tools with the end tightened were pulled in opposite directions at 200 mm / min. The strength when the notch 22 reached the lower end of the sample 20 and the sample 20 was torn into two was determined as the tear strength. The environmental temperature was set to 0 ° C., 10 ° C., and 20 ° C., and the measurement was performed on samples after being left at each environmental temperature for 30 minutes.

The tear strength of the sample at each temperature obtained by the tear test is shown in FIG. As shown in FIG. 5, the tear strength at 0 ° C. is 76.0 N / mm in the sample of the example, whereas it is 39.7 N / mm in the commercially available sample. Even at 10 ° C., the tear strength of the sample of the example is not changed to 76.0 N / mm, but the sample of the commercial product is reduced to 29.1 N / mm. At 20 ° C., the tear strength of the example sample is slightly reduced, but it is still 59.8 N / mm. The tear strength of the example sample at 20 ° C. is nearly three times as large as 20.0 N / mm of the commercially available sample.

As described above, it was confirmed that the belt of the example including the polyurethane-based thermoplastic elastomer in the core layer had higher tear strength than the commercially available belt including the polyamide-based thermoplastic elastomer in the core layer regardless of the environmental temperature. It was done. In addition, the belt of the example also has a tension at 5% elongation that is improved over the prior art.

DESCRIPTION OF SYMBOLS 10 Paper sheet conveyance belt 12 Core body layer 14 Rubber layer 16 Conductive resin layer

Claims

A core layer containing a polyurethane-based thermoplastic elastomer;
A rubber layer provided on one surface of the core layer;
A paper sheet conveying belt comprising a conductive resin layer provided on the other surface of the core layer.
The paper sheet conveying belt according to claim 1, wherein the core layer has a hardness (JIS-A) of 90 to 98 °.
3. The paper sheet conveying belt according to claim 1, wherein a thickness of the core layer is 70 to 90% of a thickness of the entire paper sheet conveying belt.
The paper sheet conveying belt according to any one of claims 1 to 3, wherein both ends are joined by heat fusion so as to be endless.