Conveyor belt and manufacturing method thereof

Abstract

The present invention provides a conveyor belt and a method for manufacturing the same, the conveyor belt being capable of ensuring excellent impact resistance against impact generated by a conveyed object put onto an upper cover rubber even in a low-temperature state. An upper cover rubber (3) and a lower cover rubber (4) are respectively arranged on the upper and lower sides of the core layer (2), a buffer layer (5) is arranged between the core layer (2) and the upper cover rubber (3), the buffer layer (5) is made into a structure comprising a woven fabric (6), an upper coating rubber layer (7) and a lower coating rubber layer (8), the woven fabric (6) is provided with warp threads (6a) extending in the length direction of the belt and weft threads (6b) extending in the width direction of the belt, and the upper coating rubber layer (7) and the lower coating rubber layer (8) are arranged on the upper and lower sides of the core layer (2). The upper rubber coating layer (7) and the lower rubber coating layer (8) respectively cover the upper surface and the lower surface of the woven fabric (6), the fineness of the woven fabric (6) in the length direction of the belt is 26000 dtex / cm or more, the fineness of the woven fabric (6) in the width direction of the belt is 90000 dtex / cm or more, the tensile strength in the length direction of the belt is 2000 N / cm or more, and the tensile strength in the width direction of the belt is 6000 N / cm or more. The layer thickness of the upper rubber coating layer (7) and the lower rubber coating layer (8) is 0.5 mm or more.

Description

Technical Field

[0001] The present invention relates to a conveyor belt and a method for manufacturing the same, and more particularly to a conveyor belt and a method for manufacturing the same that can ensure excellent impact resistance against impacts caused by conveyed objects dropped onto an upper cover rubber even in a low temperature state. Background Art

[0002] A core layer is embedded between the upper cover rubber and the lower cover rubber of the conveyor belt, and bears the tension acting on the conveyor belt. When the conveyed object is placed on the upper cover rubber, the upper cover rubber is impacted, so a structure in which a protective fiber layer is embedded in the upper cover rubber to protect the core layer is proposed (see Patent Document 1).

[0003] Even if such a protective fiber layer is embedded, the core layer is easily damaged when the impact from the conveyed object increases, thereby shortening the service life of the conveyor belt. In addition, the impact resistance of a conveyor belt used in a low temperature state such as below freezing point is lower than when used at room temperature, and the lower the temperature, the lower the impact resistance. Therefore, there is still room for improvement in ensuring that the conveyor belt has excellent impact resistance against the impact generated by the conveyed object dropped onto the upper cover rubber even in a low temperature state.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-19637 Summary of the invention

[0007] Problems to be solved by the invention

[0008] An object of the present invention is to provide a conveyor belt and a method for manufacturing the same, wherein the conveyor belt can ensure excellent impact resistance against impacts caused by conveyed objects dropped onto an upper cover rubber even in a low temperature state.

[0009] Technical means of solving problems

[0010] In order to achieve the above-mentioned purpose, the conveyor belt of the present invention is characterized in that it comprises: a core layer; an upper covering rubber and a lower covering rubber which are arranged up and down with the core layer sandwiched therebetween; and a buffer layer which is arranged at a position higher than the core layer, wherein the buffer layer comprises: a fabric having warps extending in the belt length direction and wefts extending in the belt width direction; and an upper coating rubber layer and a lower coating rubber layer which respectively cover the upper surface and the lower surface of the fabric, and the buffer layer is arranged between the core layer and the upper covering rubber, the fabric has a fineness of 26000 dtex / cm or more in the belt length direction, a fineness of 90000 dtex / cm or more in the belt width direction, a tensile strength of 2000 N / cm or more in the belt length direction, a tensile strength of 6000 N / cm or more in the belt width direction, and a layer thickness of 0.5 mm or more for the upper coating rubber layer and the lower coating rubber layer.

[0011] The manufacturing method of the conveyor belt of the present invention is characterized in that the conveyor belt is provided with a core layer between an upper cover rubber and a lower cover rubber, and a buffer layer is provided at a position higher than the core layer. In the manufacturing method, a molded body is formed, and the buffer component of the molded body as the buffer layer comprises: a fabric having warps extending in the belt length direction and wefts extending in the belt width direction; an unvulcanized upper coating rubber layer and an unvulcanized lower coating rubber layer, which respectively cover the upper surface and the lower surface of the fabric, and the fineness of the fabric in the belt length direction is 26000 dtex / cm or more, and the belt The fineness in the width direction is more than 90000 dtex / cm, the tensile strength in the belt length direction is more than 2000 N / cm, and the tensile strength in the belt width direction is more than 6000 N / cm. The core layer is arranged between the unvulcanized upper cover rubber and the unvulcanized lower cover rubber, and the buffer component is arranged between the core layer and the unvulcanized upper cover rubber. In addition, the molded body is vulcanized to manufacture a conveyor belt in which the constituent parts of the molded body are integrated and the thickness of the vulcanized upper coating rubber layer and the lower coating rubber layer is more than 0.5 mm.

[0012] Effects of the Invention

[0013] According to the present invention, by arranging the buffer layer between the core layer and the upper cover rubber, the entire thickness of the upper cover rubber can be used as a buffer for the impact generated by the conveyed object placed on the upper cover rubber, so it is helpful to prevent the buffer layer from being damaged. Moreover, by setting the fineness of the fabric in the belt length direction, the fineness in the belt width direction, the tensile strength in the belt length direction, and the tensile strength in the belt width direction within the above ranges, the impact resistance of the fabric is greatly improved. Moreover, by setting the layer thickness of the upper coating rubber layer and the lower coating rubber layer to be more than 0.5 mm, the buffer layer can be firmly integrated with the core layer and the upper cover rubber. As a result, the excellent impact resistance of the buffer layer can be fully utilized, and even if the conveyor belt is in a low temperature state, the conveyor belt can obtain excellent impact resistance for the impact generated by the conveyed object placed on the upper cover rubber. Therefore, it is helpful to avoid damage to the core layer, thereby extending the service life of the conveyor belt. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The diagram is an explanatory diagram showing an example of an embodiment of a conveyor belt from a cross-sectional perspective.

[0015] Figure 2 This is shown as an example from the top view. Figure 1 Illustration of a conveyor belt with a portion cut away.

[0016] Figure 3 This is an example from a bird's-eye view. Figure 1 Illustration of the fabric.

[0017] Figure 4 This is an explanatory diagram showing an example of improvement of the fabric from a top view.

[0018] Figure 5 This is an explanatory diagram showing, in cross-sectional view, an example of a formed body formed in a conveyor belt forming step.

[0019] Figure 6 The diagram is an explanatory diagram showing an embodiment of a conveyor belt installed on a conveying device from a side view.

[0020] Figure 7 yes Figure 6 AA line cross-section diagram. DETAILED DESCRIPTION

[0021] The conveyor belt and the manufacturing method thereof of the present invention will be described below based on the embodiments shown in the drawings. In addition, arrows W and L in the drawings respectively indicate the belt width direction and the belt length direction, and the dashed line CL indicates the center of the belt width direction.

[0022] Figure 1 to Figure 3The embodiment of the conveyor belt 1 shown in the example comprises: a core layer 2; an upper cover rubber 3 and a lower cover rubber 4 arranged up and down with the core layer 2 interposed therebetween; and a buffer layer 5 arranged between the core layer 2 and the upper cover rubber 3. In addition to these components, the conveyor belt 1 also appropriately comprises known components such as end rubbers arranged at both ends in the belt width direction W. The conveyor belt 1 is formed by integrating the above components through a vulcanization process. Figure 2 The conveyor belt 1 is shown in a state where the upper cover rubber 3 and a part of the breaker layer 5 are cut away to expose the core layer 2 (steel cords 2a).

[0023] The conveyor belt 1 is formed into a ring shape with a necessary length when in use. In the ring-shaped conveyor belt 1, the lower cover rubber 4, the core layer 2, the buffer layer 5, and the upper cover rubber 3 are sequentially stacked from the inner circumference to the outer circumference and extend over the entire length of the belt in the length direction L to form a ring shape.

[0024] The core 2 bears the tension acting on the conveyor belt 1. The core layer 2 has a plurality of steel cords 2a arranged in the belt width direction W. These steel cords 2a are covered with buffer rubber. The outer diameter of the steel cord 2a is, for example, greater than 6.0 mm and less than 15.0 mm. The density (roots / 5 cm) of the arranged steel cords 2a is, for example, greater than 2 and less than 8. The core layer 2 is arranged roughly over the entire belt width (more than 95% of the belt width).

[0025] The buffer rubber is a well-known adhesive rubber with excellent adhesiveness, and its layer thickness (covering thickness) is, for example, 0.5 mm to 4.0 mm above and below the steel cord 2a. As the buffer rubber, for example, natural rubber, styrene-butadiene rubber, butadiene rubber, or a combination of two or more thereof can be used.

[0026] As the upper cover rubber 3 and the lower cover rubber 4, for example, a known rubber formed of a diene rubber containing at least natural rubber (if oil resistance is required, acrylonitrile butadiene rubber may also be contained) and having good wear resistance by carbon black, etc. can be used. The layer thickness of the upper cover rubber 3 and the lower cover rubber 4 is appropriately determined according to the performance required for the conveyor belt 1. The layer thickness of the upper cover rubber 3 is, for example, not less than 10 mm and not more than 45 mm, and the layer thickness of the lower cover rubber 4 is, for example, not less than 5 mm and not more than 35 mm.

[0027] The main function of the buffer layer 5 is to prevent damage to the core layer 2 and protect it. The buffer layer 5 has a fabric 6, an upper coating rubber layer 7 and a lower coating rubber layer 8 respectively covering the upper surface and the lower surface of the fabric 6. Since the tension acting on the conveyor belt 1 is basically borne by the core layer 2, the buffer layer 5 is not actually subjected to tension.

[0028] The buffer layer 5 is arranged at least in the central part of the belt width direction W of the conveyor belt 1. The central part of the belt width direction W refers to the range of the central part of the belt width direction W that is about 50% or more and 70% or less of the belt width. The buffer layer 5 is preferably set to a specification that is roughly arranged over the entire belt width (more than 95% of the belt width) so that it substantially covers the entire width of the upper surface of the core layer 2.

[0029] The layer thickness t1 of the upper coating rubber layer 7 and the layer thickness t2 of the lower coating rubber layer 8 are 0.5 mm or more, and are set to be 1.0 mm or more to ensure a stronger adhesive force. When the respective layer thicknesses t1 and t2 increase, the weight of the conveyor belt 1 also increases, so in order to avoid excessive weight increase, the upper limit is, for example, 2.0 mm. The respective layer thicknesses t1 and t2 are basically the same, but may be different.

[0030] The upper coating rubber layer 7 and the lower coating rubber layer 8 are formed of the same known rubber, for example, natural rubber, butyl rubber, butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, or a rubber mixed with several of them. The upper coating rubber layer 7 and the lower coating rubber layer 8 are firmly bonded to the fabric 6. Moreover, the upper coating rubber layer 7 is firmly bonded to the upper cover rubber 3, and the lower coating rubber layer 8 is firmly bonded to the core layer 2.

[0031] like Figure 3 As illustrated, the fabric 6 has warp threads 6 a extending in the belt length direction L and weft threads 6 b extending in the belt width direction W. Figure 3 The fabric 4 has a plain woven mat structure in which one warp thread 6a and two weft threads 6b are alternately crossed up and down.

[0032] Fabric 6 is not limited to Figure 3 The illustrated pad structure may also adopt other structures having warp 6a and weft 6b. Figure 4 As illustrated, a simple plain weave structure in which one warp thread 6a and one weft thread 6b are alternately crossed up and down may be used.

[0033] The material of the warp 6a and the weft 6b can be polyamide resin such as nylon 6, nylon 66, etc. The warp 6a and the weft 6b are made into a twisted structure in which a plurality of monofilaments are twisted. The fineness of the monofilament is set to 900 dtex or more and 2500 dtex or less, for example.

[0034] In order to ensure sufficient impact resistance, the fabric 6 is made to a special specification. That is, the fineness D1 of the fabric 6 in the belt length direction L is 26000 dtex / cm or more, the fineness D2 in the belt width direction W is 90000 dtex / cm or more, the tensile strength F1 in the belt length direction L is 2000 N / cm or more, and the tensile strength F2 in the belt width direction W is 6000 N / cm or more. In order to avoid an increase in weight or a decrease in bendability of the conveyor belt 1, the upper limits of the fineness D1 and D2 are, for example, 35000 dtex / cm and 110000 dtex / cm, respectively, and the upper limits of the tensile strength F1 and tensile strength F2 are, for example, 3000 N / cm and 7000 N / cm, respectively.

[0035] The finenesses D1 and D2 are values ​​calculated from the following formula.

[0036] Denier D1 = total denier d1 (dtex) of warp 6a × density of warp 6a (roots / 5cm) ÷ 5

[0037] Denier D2 = total denier d2 (dtex) of weft 6b × density of weft 6b (roots / 5cm) ÷ 5

[0038] The total fineness d1 (dtex) of the warp yarn 6a is the fineness (dtex) of the single yarn constituting the warp yarn 6a×the number of the single yarns, and the total fineness d2 (dtex) of the weft yarn 6b is the fineness (dtex) of the single yarn constituting the weft yarn 6b×the number of the single yarns.

[0039] The warp yarn 6a has, for example, a 1400 dtex / n structure formed by twisting n (n=2-4) monofilaments having a fineness of 1400 dtex, or a 2100 dtex / n structure formed by twisting n (n=2-3) monofilaments having a fineness of 2100 dtex.

[0040] The weft yarn 6b is, for example, made by twisting n single yarns (n=7~10) with a fineness of 1400dtex, and then twisting m groups (m=2~3) of the twisted n single yarns to form a 1400dtex / n / m structure, or by twisting n single yarns (n=5~8) with a fineness of 2100dtex, and then twisting m groups (m=2~3) of the twisted n single yarns to form a 2100dtex / n / m structure.

[0041] The density (threads / 5 cm) of the warp threads 6 a is, for example, not less than 50 and not more than 70. The density (threads / 5 cm) of the weft threads 6 b is, for example, not less than 8 and not more than 12.

[0042] The tensile strengths F1 and F2 were measured based on the tensile strength test specified in JIS L1096 and were obtained by dividing the breaking load of a test piece (length 400 mm, width 10 mm) of fabric 6 by the width of the test piece. In this test, the tensile speed was 200 mm / min and the clamping interval was 200 mm.

[0043] In conventional fabrics, the fineness D1 is less than 10000 dtex / cm, the fineness D2 is less than 35000 dtex / cm, the tensile strength F1 is less than 700 N / cm, and the tensile strength F2 is less than 2000 N / cm. Therefore, in this embodiment, the fineness D1, D2, tensile strength F1 and tensile strength F2 are greatly improved compared with conventional fabrics, and the fabric 6 is highly rigid.

[0044] In order to manufacture the above-mentioned conveyor belt 1, a Figure 5 The molded body 9 shown in the example. In order to mold the molded body 9, an unvulcanized upper cover rubber 3A, an unvulcanized lower cover rubber 4A, a core layer 2 and a cushioning member 5A are used. The cushioning member 5A has a fabric 6, an unvulcanized upper coating rubber layer 7A and an unvulcanized lower coating rubber layer 8A covering the upper and lower surfaces of the fabric 6, respectively.

[0045] Then, for example, the core layer 2, the cushioning component 5A, and the unvulcanized upper cover rubber 3A are sequentially stacked on the unvulcanized lower cover rubber 4A to form a molded body 9. Alternatively, the core layer 2, the cushioning component 5A, the core layer 2, and the unvulcanized lower cover rubber 4A may be sequentially stacked on the unvulcanized upper cover rubber 3A to form a molded body 9. That is, the above-mentioned components are used and a molded body 9 is formed by a known method. Figure 5 The formed body 9 is sufficient.

[0046] Next, the molded body 9 is vulcanized using a known vulcanizing device. After the vulcanization process, the unvulcanized rubber constituting the molded body 9 is vulcanized, and the various components are joined and integrated to form the conveyor belt 1. The buffer component 5A becomes the buffer layer 5 after the vulcanization process, and the layer thickness of the unvulcanized upper coating rubber layer 7A and the unvulcanized lower coating rubber layer 8A is set to become the above-mentioned layer thickness t1 and layer thickness t2 after vulcanization. Based on the results of the previous vulcanization test, etc., the layer thickness of the unvulcanized upper coating rubber layer 7A and the unvulcanized lower coating rubber layer 8A can be set. The layer thickness of the unvulcanized upper coating rubber layer 7A and the unvulcanized lower coating rubber layer 8A is slightly larger than the layer thickness t1 and the layer thickness t2, respectively.

[0047] The necessary length of the manufactured conveyor belt 1 is formed into a ring shape and Figure 6-7The conveyor belt 1 is generally installed on a conveyor device 10 for use. In the conveyor device 10, the conveyor belt 1 is laid between a pair of pulleys 11a and 11b. On the carrier side of the conveyor device 10, the lower cover rubber 4 of the conveyor belt 1 is supported by a plurality of support rollers 12 and maintained in a groove shape protruding downward. Therefore, the conveyed object C placed on the upper cover rubber 3 is mainly placed in the central part in the belt width direction. On the return side of the conveyor device 10, the upper cover rubber 3 is supported by a plurality of support rollers 12.

[0048] In the conveyor belt 1, since the buffer layer 5 is disposed between the core layer 2 and the upper cover rubber 3, the entire thickness of the upper cover rubber 3 can be used to mitigate and absorb the impact of the conveyed object C placed on the upper cover rubber 3. That is, the upper cover rubber 3 can maximize the function of the buffer material. Therefore, the conveyor belt 1 can effectively mitigate and absorb the impact even in a low temperature state below freezing, so it is difficult to damage the buffer layer 5, which is conducive to preventing damage to the core layer 2.

[0049] In addition, the fineness D1 and fineness D2 of the fabric 6 are set to 26000 dtex / cm or more and 90000 dtex / cm or more, respectively, and the tensile strength F1 and tensile strength F2 of the fabric 6 are set to 2000 N / cm or more and 6000 N / cm or more, respectively. That is, the fabric 6 is highly rigid, and the impact resistance is greatly improved compared with conventional fabrics.

[0050] Furthermore, by setting the layer thickness t1 and t2 of the upper coating rubber layer 7 and the lower coating rubber layer 8 to be greater than 0.5 mm, the buffer layer 5 can be firmly integrated with the core layer 2 and the upper covering rubber 3. By setting the layer thickness t1 and t2 to be greater than 1.0 mm, the buffer layer 5 can be more firmly integrated with the core layer 2 and the upper covering rubber 3. Since the buffer layer 5 is difficult to peel off from the surrounding components, the excellent impact resistance of the buffer layer 5 can be fully exerted. As a result, even if the conveyor belt 1 is in a low temperature state, the conveyor belt 1 can obtain excellent impact resistance against external impacts. Therefore, it is beneficial to avoid damage to the core layer 2 and can extend the service life of the conveyor belt 1.

[0051] The conveyor belt 1 may be used in an environment below -20°C. Under such low temperature conditions, the impact resistance of the conveyor belt 1 is reduced due to the low-temperature embrittlement of the rubber. In the conveyor belt 1, the buffer layer 5 is arranged between the core layer 2 and the upper cover rubber 3, and the layer thickness t1 and t2 of the upper coating rubber layer 7 and the lower coating rubber layer 8 are set within the above range using the above-mentioned special specification fabric 6, thereby ensuring practical impact resistance even in an environment below -20°C (for example, an environment around -50°C).

[0052] In the conveyor belt 1, the fineness D2 is much larger than the fineness D1, so the tensile strength F2 is much larger (more than 3 times) than the tensile strength F1, which is helpful in preventing the longitudinal tear of the conveyor belt 1. Even if longitudinal tear occurs, the longitudinal tear length can be suppressed to a minimum. Figure 3 The braided structure (mat structure) shown in the example is Figure 4 Compared with the simple plain weave structure exemplified above, a higher effect of suppressing longitudinal tearing of the conveyor belt 1 can be expected.

[0053] like Figure 6 As shown in the example, the conveyor belt 1 repeatedly bends around the pulleys 11a and 11b. During this bending, the core layer 2 becomes a neutral plane, and a tensile force is generated on the side closer to the outer periphery than the core layer 2, and a compressive force is generated on the side closer to the inner periphery than the core layer 2. Therefore, if there is a component with higher rigidity at a position farther away from the core layer 2 in the arc-shaped bending state in the radial direction, the bending rigidity will become higher and the bendability will be reduced. Although the conveyor belt 1 has a buffer layer 5 with higher rigidity than a conventional conveyor belt, the buffer layer 5 is not buried in the upper cover rubber 3, but is arranged adjacent to the core layer 2. Therefore, the buffer layer 5 is present at a position closer to the core layer 2 in the arc-shaped bending state in the radial direction, which helps to avoid a reduction in the bendability of the conveyor belt 1.

[0054] In addition, if Figure 7 As shown, the conveyor belt 1 is deformed into a groove shape that protrudes moderately downward on the carrier side of the conveying device 10 to accommodate the conveyed object C. In this way, when the conveyor belt 1 is deformed into a groove shape, the core layer 2 also becomes a neutral surface. Therefore, although the conveyor belt 1 has a buffer layer 5 with higher rigidity than a conventional conveyor belt, it is also helpful to avoid the reduction of the groove property of the conveyor belt 1 (difficult to deform into a groove shape). In order to maintain the bendability and groove property of the conveyor belt 1 well, it can also be made into the following specifications: the layer thickness t2 of the lower coating rubber layer 8 is made smaller than the layer thickness t1 of the upper coating rubber layer 7, so that the buffer layer 5 is closer to the core layer 2.

[0055] Example

[0056] As shown in Table 1, 6 types of buffer layers (conventional example, comparative examples 1 to 2, and embodiments 1 to 3) with different specifications were prepared, and the tensile strength F1 in the belt length direction (the direction in which the warp yarns extend) and the tensile strength F2 in the belt width direction (the direction in which the weft yarns extend) were measured for each fabric. The tensile strengths F1 and F2 are measured values ​​obtained by the above-mentioned test method.

[0057] In addition, the covering rubber and the buffer rubber are laminated with the buffer layer formed by covering the upper and lower parts of each fabric with the coating rubber layer (the layer thickness t1 and t2 are set to be the same), and vulcanized under common conditions to make them integrated to produce bonding test pieces. Using each bonding test piece, the peel strength is measured according to JIS K6256-1:2013 "Peel strength with cloth". The results of each measurement are shown in Table 1. In addition, the peel strength between the buffer layer and the buffer rubber is equivalent to the peel strength between the buffer layer and the core layer.

[0058] [Table 1]

[0059]

[0060] If the tensile strengths F1 and F2 are 2000 N / cm or more and 6000 N / cm or more, respectively, it can be evaluated that the impact resistance is sufficient for practical use even at freezing point. In addition, if the peel strength between the fabric and the upper coating rubber layer and the lower coating rubber layer is 10.5 N / mm or more, it can be evaluated that the adhesion is sufficient for practical use even at freezing point.

[0061] From the results in Table 1, it can be seen that compared with the conventional examples, the tensile strengths F1 and F2 of Examples 1 to 3 are greatly improved, and the peeling strength between the fabric and the upper coating rubber layer and the lower coating rubber layer is also greatly improved. Moreover, the tensile strengths F1 and F2 of Examples 1 to 3 are respectively more than 2000N / cm and more than 6000N / cm, and sufficient impact resistance can be expected even at freezing point. In addition, the peeling strength between the fabric and the upper coating rubber layer and the lower coating rubber layer also has very excellent performance, so the excellent impact resistance of the fabric can be exerted without being damaged.

[0062] Description of Reference Numerals

[0063] 1: Conveyor belt

[0064] 2: Core layer

[0065] 2a: Steel cord

[0066] 3: Covering glue

[0067] 3A: Uncured top cover rubber

[0068] 4: Bottom cover glue

[0069] 4A: Uncured lower cover rubber

[0070] 5: Buffer layer

[0071] 5A: Buffer components

[0072] 6: Fabric

[0073] 6a: Warp

[0074] 6b: Weft

[0075] 7: Rubber coating

[0076] 7A: Unvulcanized upper coating rubber layer

[0077] 8: Lower coating rubber layer

[0078] 8A: Unvulcanized lower coating rubber layer

[0079] 9: Molded body

[0080] 10: Conveying device

[0081] 11a, 11b: Pulley

[0082] 12: Support roller

[0083] C: Transported objects

Claims

1. A conveyor belt, comprising: a core layer; an upper cover rubber and a lower cover rubber disposed up and down with the core layer sandwiched therebetween; and a buffer layer disposed above the core layer, wherein: The buffer layer comprises: a fabric having warps extending in the length direction of the belt and wefts extending in the width direction of the belt; and an upper coating rubber layer and a lower coating rubber layer, which respectively cover the upper surface and the lower surface of the fabric, and the buffer layer is arranged between the core layer and the upper covering rubber. The fabric has a fineness of 26,000 dtex / cm or more in the length direction, a fineness of 90,000 dtex / cm or more in the width direction, a tensile strength of 2,000 N / cm or more in the length direction, and a tensile strength of 6,000 N / cm or more in the width direction, and the thickness of the upper coating rubber layer and the lower coating rubber layer is 0.5 mm or more. 2 . The conveyor belt according to claim 1 , wherein the upper coating rubber layer and the lower coating rubber layer have a layer thickness of 1.0 mm or more. 3 . The conveyor belt according to claim 1 , wherein the woven fabric has a mat structure in which one of the warp threads and two of the weft threads alternately cross each other vertically.

4. A method for manufacturing a conveyor belt, wherein the conveyor belt is provided with a core layer between an upper cover rubber and a lower cover rubber, and a buffer layer is provided at a position higher than the core layer, wherein a molded body is formed, and the buffer component of the molded body as the buffer layer comprises: a fabric having warps extending in the belt length direction and wefts extending in the belt width direction; an unvulcanized upper coating rubber layer and an unvulcanized lower coating rubber layer, which cover the upper surface and the lower surface of the fabric respectively, the fabric having a fineness of 26000 dtex / cm or more in the belt length direction, a fineness of 90000 dtex / cm or more in the belt width direction, a tensile strength of 2000 N / cm or more in the belt length direction, and a tensile strength of 6000 N / cm or more in the belt width direction, The core layer is arranged between the unvulcanized upper cover rubber and the unvulcanized lower cover rubber, the buffer component is arranged between the core layer and the unvulcanized upper cover rubber, and the molded body is vulcanized to manufacture a conveyor belt in which the constituent parts of the molded body are integrated and the thickness of the vulcanized upper coating rubber layer and the lower coating rubber layer is greater than 0.5 mm.

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