JPH10217347A - Conveyor belt made of resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conveyor belt not generating belt peeling and curling, having proper flexibility, having a structure hard to stretch during running and hard to stain and hard to generate foreign matter. SOLUTION: At least one net like core material 3 is arranged between both upper and lower thermoplastic resin layers 1, 2 of a conveyor belt made of a resin and both upper and lower thermoplastic resin layers 1, 2 have the same material quality and the same thickness and are integrally connected through the meshes of the net like core material 3 and the bending rigidity of the belt in a curvature of 1cm<-1> is 60gf.cm<2> /cm or less and the tensile stress at a time of 1%-elongation in a belt running direction is 5kN/m or more per belt 25mm width.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-made conveyor belt, and more particularly to a conveyor belt which is suitable for use as a conveyor belt for transporting foods, precision instruments, chemicals, etc., and which is less likely to generate contamination and foreign substances.

[0002]

2. Description of the Related Art As a conveyor belt for transporting foods, precision instruments and chemicals, generally, a woven fabric such as polyester fiber (hereinafter referred to as "canvas") is coated on one or both sides with a thermoplastic material such as polyvinyl chloride or polyurethane. What laminated | stacked resin via the adhesive agent is used in many cases. However, in these conveyor belts, since the canvas has water absorbency, mold, germs and the like easily propagate and are easily stained. Also,
Because the adhesive is interposed, the canvas and the thermoplastic resin may peel off. Furthermore, when the conveyor belt meanders and hits the guide, the belt ends are rubbed, so that the canvas is frayed, and the frayed material is mixed as foreign matter into the conveyed product.

[0003] In order to prevent such a problem from occurring, a polyester resin single-layer conveyor belt without canvas is provided, but the resin single-layer belt is easily stretched due to tension in the running direction. If a high-strength resin is used to suppress the elongation, the flexibility is reduced, and the belt does not adapt to the outer diameter of the pulley. On the other hand, when the thickness of the belt is reduced, the strength is reduced and a problem that the life of the belt is shortened occurs.

Further, a conveyor belt having a three-layer integrated structure in which both the upper layer, the intermediate layer and the lower layer are made of a thermoplastic resin is provided, but has a drawback that the belt extends in the running direction and slips, resulting in low transport efficiency. is there. If the elastic modulus is increased to solve this problem, there arises a problem that the belt does not adapt to the outer diameter of the pulley. Also, if the material and thickness of the upper and lower layers are different, so-called curling (curving)
Is more likely to occur.

JP-A-59-175648 describes a belt in which a net-like core made of polyester, nylon and a thin metal wire is embedded in a covering material made of rubber or resin. In these belts, the rubber or resin constituting the covering material penetrates into the mesh of the net-shaped core material to integrate the belt body and the core material.

However, when the belt described in the above publication is used as a conveyor belt for food or precision equipment, curling (curving in the width direction) of the belt is likely to occur, and running becomes unstable due to bending rigidity. There's a problem.

[0007]

As described above, no conveyor belt has been provided which has the flexibility to be easily wound around the pulley and satisfies both the characteristics that it is difficult to stretch during running.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to prevent the occurrence of belt peeling and curling, to provide a moderate flexibility, and to extend during running. An object of the present invention is to provide a conveyor belt having a difficult structure. Another object of the present invention is to provide a conveyor belt having a structure that is less likely to be contaminated and less likely to generate foreign matter.

[0009]

In order to solve the above-mentioned problems, the present inventors have investigated and analyzed belts that have slipped due to elongation during running on the market, and have conducted research on the aforementioned food, precision equipment and chemicals. Investigation of operating conditions of conveyor belt used for conveyance and Japanese Patent Application Laid-Open No. 2-28650
As a result of investigating the performance of a conveyor belt as a trial based on the technology disclosed in Japanese Patent Publication No. 4 and the like, as a condition of the conveyor belt to solve the above problem, the upper layer and the lower layer are made of a thermoplastic resin having the same material and the same thickness. And in between,
A net-like core body with high flexibility and high strength is arranged so that the upper and lower thermoplastic resin layers are fused and integrated with each other through the mesh, and the bending rigidity of the belt as a whole is 60 gf · at a curvature of 1 cm ⁻¹ . cm ² / cm or less, and that the tensile stress at 1% elongation in the belt running direction should be 5 kN / m or more per 25 mm width of the belt.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a resin conveyor belt having at least one net-like core disposed between thermoplastic resin layers on both upper and lower surfaces. The resin layers are of the same material and of the same thickness, and the thermoplastic resin layers on the upper and lower surfaces are integrally connected through the mesh of the net-like core, and the bending rigidity of the belt at a curvature of 1 cm ^-1 is 60 gf · cm ² / cm or less. A first aspect of the present invention is a resin conveyor belt characterized in that a tensile stress at 1% elongation in the belt running direction is 5 kN / m or more per 25 mm width of the belt. The second invention is a resin-made conveyor belt characterized in that the plastic resin layer is made of a polyolefin elastomer, and in the first or second invention, the net-shaped core is A resin conveyor belt warp constituting and weft is characterized in that it consists of monofilaments or twisted to a material polyester or polyamide and the third invention.

As the thermoplastic resin layers on the upper and lower surfaces, for example, polyethylene, polypropylene, polyvinyl chloride,
Elastomers such as polyurethane, polyester, and polyamide are exemplified. Among these, a polyolefin-based elastomer such as polyethylene or polypropylene is preferably used from the viewpoint that the conveyed material is difficult to adhere to and is easily peeled off even if adhered.

If the material and thickness of the upper and lower resin layers are different from each other, curling or poor fusion is likely to occur. Therefore, the upper and lower resin layers must be made of the same material and have the same thickness. Is particularly important.

In order to provide flexibility, the belt has a flexural rigidity of 60 gf · cm ² / cm or less at a curvature of 1 cm ⁻¹ . For this purpose, the thickness of the upper and lower resin layers is 0.2 to 0. It is preferably set to 0.6 mm.

In order to make the belt hard to stretch during running, the tensile stress at 1% stretching in the belt running direction is 25 mm for the belt.
It is preferred to be 5 kN / m or more per width.

As the yarn forming the net-shaped core, polyester, polyamide, polyaramid, metal wire, and the like can be used, but strength, net-like holding property (ease of handling during molding), lightness, and water resistance ( From the viewpoints of rust prevention and cost, polyester or polyamide is preferably used. The form of the yarn may be a monofilament or a twisted yarn.
The mesh of the net-shaped core is not particularly limited as long as the thermoplastic resin on the upper surface and the lower surface can be melted and penetrated and a necessary tensile stress is obtained, but a mesh having a square of 1.0 to 3.0 mm is usually used. Can be For forming the mesh, warp yarns and weft yarns may be alternately turned up and down to intersect to form a coarsely woven fabric, or warp yarns and weft yarns may be joined at intersections by fusion or the like.

In order to dispose a net-like core between the upper and lower thermoplastic resin layers, two thermoplastic resin sheets are extruded and molded by a calendar or the like, and the two thermoplastic resin sheets are formed. What is necessary is just to sandwich the net-shaped core between the sheets, heat and press with a roll or the like, and heat-bond the thermoplastic resin sheet. Alternatively, both sides of the net-shaped core may be covered with a thermoplastic resin while the net-shaped core is inserted into the crosshead attached to the end of the cylinder of the extruder. According to these methods, the thermoplastic resin on both sides of the net-shaped core body penetrates into the net of the net and is fused integrally, so that it does not peel off. Also, unlike a rubber conveyor belt, it does not require a core insertion step or vulcanization step, sandwiches the net-shaped core,
It can be easily molded simply by heating and melting the resin on both sides.
Further, even when the formed long belt-shaped body is joined at both ends in the length direction, it can be handled in the same manner as a conveyor belt using a normal cord or canvas core.

[0017]

EXAMPLES Examples of the resin conveyor belt of the present invention will be described below using specific numerical values, but the present invention is not limited to the following examples.

Example 1 As shown in FIG. 1, an upper layer 1 and a lower layer 2 were made of a polyolefin elastomer sheet having a thickness of 370 μm (“HIZEX 8200 manufactured by Mitsui Petrochemical Co., Ltd.).
B) and “Dynalon 6200P” manufactured by Nippon Synthetic Rubber Co., Ltd. in a weight ratio of 7: 3), and the intermediate layer 3 is a polyester monofilament net-shaped core (“TB20” manufactured by NBC Industries, Ltd.). 170 ° C, pressure 40k
g / cm ² and thermocompression bonding, as shown in FIG.
A resin conveyor belt having a layer integrated structure was obtained.

Example 2 As the upper layer 1 and the lower layer 2,
A resin-made conveyor belt having a three-layer integrated structure was obtained under the same conditions as in Example 1 except that a polyolefin-based elastomer sheet ("Cataalloy CA-10" manufactured by Montell Co.) having a thickness of 500 µm was used.

Example 3 A polyamide monofilament net-shaped core ("NB" manufactured by NBC Industries, Ltd.) was used for the intermediate layer 3.
20)), except that a resin conveyor belt having a three-layer integrated structure was obtained under the same conditions as in Example 1.

[Embodiment 4] A net-shaped core of polyamide monofilament ("NB" manufactured by NBC
20)), except that a resin conveyor belt having a three-layer integrated structure was obtained under the same conditions as in Example 2.

Example 5 A three-layer integrated structure was prepared under the same conditions as in Example 1 except that a net-shaped core of polyester twisted yarn ("T-180" manufactured by NBC Industries) was used for the intermediate layer 3. A resin conveyor belt was obtained.

Further, a conveyor belt for comparison with the conveyor belts of the above-mentioned Examples 1 to 5 was manufactured. [Comparative Example 1] An adhesive was applied to both sides of a polyurethane-based elastomer sheet having a thickness of 250 µm, sandwiched between two canvases (polyester woven cloth), and a sheet having a thickness of 250 was applied to one side.
A polyurethane elastomer sheet having a thickness of μm was overlaid and thermocompressed under the conditions of a temperature of 150 ° C. and a pressure of 5 kg / cm ² to obtain a four-layer integrated belt.

Comparative Example 2 A polyolefin elastomer sheet having a thickness of 370 μm (“HIZEX 8200B” manufactured by Mitsui Petrochemical Co., Ltd. and “Dynalon 6200P” manufactured by Nippon Synthetic Rubber Co., Ltd.) was compounded in the upper layer 1 in a weight ratio of 7: 3. The lower layer 2 is made of the same material as the upper layer 1 and made of a polyolefin elastomer sheet having a thickness of 200 μm, and the intermediate layer 3 is made of a polyester monofilament net-shaped core (NBC).
The product was manufactured as “TB20” manufactured by Kogyo Co., Ltd.) and thermocompression-bonded under the conditions of a temperature of 170 ° C. and a pressure of 40 kg / cm ² to obtain a conveyor belt having a three-layer integrated structure.

Comparative Example 3 The upper layer 1 and the lower layer 2 were
μm polyester elastomer sheet ("Belprene S-9002", manufactured by Toyobo Co., Ltd.), the intermediate layer 3 is a polyester monofilament net-shaped core ("TB20", manufactured by NBC Industries, Ltd.), and the temperature is 230.degree. 5
Thermocompression bonding was performed under the condition of 0 kg / cm ² to obtain a conveyor belt having a three-layer integrated structure.

Comparative Example 4 A polyolefin-based elastomer sheet having a thickness of 500 μm (a mixture of “HIZEX 8200B” manufactured by Mitsui Petrochemical Co., Ltd. and “Dynalon 6200P” manufactured by Nippon Synthetic Rubber Co., Ltd.) at a weight ratio of 7: 3. , A polyamide monofilament net (“NB20” manufactured by NBC Industries, Ltd.) at a temperature of 170 ° C. and a pressure of 40 kg / c.
Thermocompression bonding was performed under the conditions of m ² to obtain a conveyor belt having a two-layer structure.

Next, Tables 1 and 2 show the characteristic evaluation results of the conveyor belts of the respective examples and comparative examples manufactured as described above.

The characteristic evaluation method is as follows.

[0029] Thread fraying and fluffing. Conveyor Belt 3
As a result of visually evaluating the state of the belt end portion after running for 00 hours, "the case where there was no thread fraying and fuzzing" is shown as "O", and "the case where there is thread fraying and fuzzing" is shown as "x".

Flexibility (Bending rigidity) A test piece having a length of 50 mm and a width of 3 mm was bent to a curvature of 1 cm ^-1 by a pure bending tester, and a value obtained by dividing the slope of the obtained bending deformation curve by the width of the test piece (bending) (Rigidity), “bending rigidity of 60 gf · cm ² / cm or less” is indicated by “○”, and “bending rigidity of more than 60 gf · cm ² / cm” is indicated by ×.

Strength (1% Modulus) A test piece of 300 mm length × 25 mm width (200 mm between marked lines) was pulled at a speed of 50 mm / min by a tensile tester, and the load when 1% stretched between marked lines was 1%. % Modulus. "1% modulus is 5kN / m or more"
○, “× 1% modulus less than 5 kN / m” ×
As shown.

After the production of the curling conveyor belt, “Circles with a belt end warpage of 5 mm or less” were evaluated as “Good” according to the state of the belt end warpage.
"A belt having a warpage of the end of more than 5 mm" is indicated as "Belt end".

[0033]

[Table 1]

[0034]

[Table 2]

As is clear from Tables 1 and 2, the one according to the present embodiment has no fraying or fluff, has excellent flexibility, high strength, and does not cause curling.
However, in the case of Comparative Example 1, since the canvas was used, yarn fraying and fluffing were observed. In the case of Comparative Example 2, curling occurred because the thickness of the upper layer was different from that of the lower layer. Furthermore, in the case of Comparative Example 3, since the upper layer and the lower layer are made of the polyester elastomer sheet, the bending rigidity is too high and the flexibility is inferior. And the thing of the comparative example 4 does not have a polyolefin-type elastomer sheet in a lower layer, Therefore, intensity | strength is low and curling generate | occur | produced.

[0036]

The resin conveyor belt of the present invention is constructed as described above, and has the following effects. Does not cause belt peeling or curling, is less likely to be contaminated, and is less likely to generate foreign matter. Since it has relatively high strength, it is difficult to stretch during traveling, and it is possible to transport articles with high efficiency without slipping. Since it has appropriate flexibility, it can be smoothly wound around the pulley.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a resin conveyor belt of the present invention.

FIG. 2 is a sectional view of the resin conveyor belt of the present invention.

[Explanation of symbols]

 1: Upper layer (thermoplastic resin layer) 2: Lower layer (thermoplastic resin layer) 3: Middle layer (net-shaped core)

Claims (3)

[Claims] 1. A resin conveyor belt in which at least one net-shaped core is disposed between upper and lower thermoplastic resin layers, wherein the upper and lower thermoplastic resin layers have the same material and the same thickness. The thermoplastic resin layers on both the upper and lower surfaces are integrally connected through the mesh of the net-shaped core, and have a curvature of 1
The bending rigidity of the belt at cm ^-1 is 60 gf · cm ² /
cm, and a tensile stress at 1% elongation in the belt running direction is 5 kN / m or more per 25 mm width of the belt. 2. The resin conveyor belt according to claim 1, wherein the upper and lower thermoplastic resin layers are made of a polyolefin elastomer. 3. The resin conveyor belt according to claim 1, wherein the warp yarns and the weft yarns constituting the net-shaped core are made of a monofilament or a twisted yarn made of polyester or polyamide.