Conveyance belt

Abstract

Provided is a conveyance belt that can reduce the amount of wear caused by friction with a conveyed object and sliding, and can suppress a decrease in conductivity when a conductive coating is provided. A conveyance belt 10 includes: a core body 11; a front surface canvas 12 bonded to one surface of the core body 11; a back surface canvas 14 bonded to the other surface of the core body 11; and a conductive coating 13 formed at least on the front surface of the front surface canvas 12. The front surface canvas 12 is configured to include: weft yarns; and warp made of a resin material having a higher melting point than that of the weft. The weft forming the core body 11 and the front surface canvas 12 comprises, for example, aliphatic polyamide, and the warp forming the front surface canvas 12 comprise, for example, aliphatic polyamide, semi-aromatic polyamide, or wholly aromatic polyamide.

Description

Carriage belt

[0001] The present invention relates to a carriage belt.

[0002] For the carriage belt used in a roller conveyor, for example, a canvas containing warp and weft is used, and a resin material or a rubber material is used as a treatment agent for the canvas to provide durability.

[0003] In particular, the carriage belt used for transporting heavy objects is required to have abrasion resistance because the load on the carriage belt by the object to be transported is large. The surface canvas of the carriage surface is worn due to heat generation caused by friction and sliding of the material, and the core base material is exposed, resulting in a loss of the carriage capacity.

[0004] When there is a stopper mechanism in the roller conveyor, there is a problem that the carriage belt is easily damaged due to heat generation caused by sliding between the bottom surface of the object to be transported and the carriage belt.

[0005] Patent Document 1 discloses a winding transmission device that winds a transmission belt around a drive pulley and transmits power to a driven pulley. The transmission belt is described as having a wrapping belt made of a canvas in which natural fibers form warp threads and synthetic fibers form weft threads.

[0006] Patent Document 2 discloses a curved belt that includes a first conductive member disposed along a first direction and a second conductive member disposed along a second direction intersecting the first direction in the canvas. The first and second conductive members remove static electricity charged on the belt over the entire belt.

[0007] Patent Document 3 discloses a flat belt including a core canvas, a first resin layer and a first outer canvas sequentially laminated on one surface of the core canvas, a first rubber layer laminated on the first outer canvas with an adhesive, a second resin layer and a second outer canvas sequentially laminated on the other surface of the core canvas, and a second rubber layer laminated on the second outer canvas with an adhesive. The sum of the thickness of the first rubber layer and the thickness of the second rubber layer is 15 to 65% of the body thickness of the flat belt.

[0008] Japanese Patent Application Laid-Open No. 58-109753 Japanese Patent Application Laid-Open No. 2008-239314 Japanese Patent Application Laid-Open No. 2016-088681

[0009] When natural fibers are used in the weft threads, as in the transmission belt described in Patent Document 1, the natural fibers become fuzzy and dirty during use, making it difficult to improve abrasion resistance while solving the above problem.

[0010] Conventional conveyor belts, especially when used to transport heavy objects, suffer from significant wear due to friction and sliding with the transported object, leading to belt deterioration such as exposure of the core. Furthermore, when a conductive coating is applied to the surface canvas of the conveyor belt to impart conductivity, the conductive coating wears down due to friction and sliding with the transported object, resulting in a decrease in conductivity.

[0011] The present invention aims to provide a conveyor belt that can reduce wear due to friction and sliding with the conveyed object and suppress the decrease in conductivity when a conductive coating is provided.

[0012] The conveyor belt of the present invention comprises a core body, a surface canvas bonded to one side of the core body, a back canvas bonded to the other side of the core body, and a conductive coating formed on at least the surface of the surface canvas, wherein the surface canvas comprises weft threads and warp threads made of a resin material with a higher melting point than the weft threads.

[0013] The present invention provides a conveyor belt that can reduce the amount of wear due to friction and sliding with the object being conveyed, and suppress the decrease in conductivity when a conductive coating is provided.

[0014] This is a cross-sectional view of a belt according to an embodiment of the present invention. This is a schematic diagram of a sliding test apparatus according to an embodiment of the present invention. This is a graph showing the measurement results according to an embodiment of the present invention.

[0015] Embodiments of the present invention will be described below. However, the embodiments described below are merely illustrative and can be modified as appropriate to those skilled in the art.

[0016] <Embodiment> (Configuration of the conveyor belt 10) Figure 1 is a cross-sectional view of the conveyor belt 10 according to this embodiment. The conveyor belt 10 of this embodiment has a core body 11, a surface canvas 12 adhered to one side of the core body 11, and a conductive coating 13 formed on the surface of the surface canvas 12. The side of the conveyor belt 10 on which the surface canvas 12 and the conductive coating 13 are provided is the conveying surface 10A for conveying the object to be conveyed. The conveyor belt 10 further has a back canvas 14 adhered to the other side of the core body 11, and a conductive coating 15 formed on the surface of the back canvas 14. The side of the conveyor belt 10 on which the back canvas 14 and the conductive coating 15 are provided is the side opposite to the conveying surface 10A, and is the surface 10B that contacts the conveying pulley.

[0017] The core 11 is made of an aliphatic polyamide such as PA6 (a polyamide obtained by ring-opening polymerization of ε-caprolactam), and more specifically, PA6. The core 11 is a base material obtained by extruding the material resin that will become the core 11 into a sheet shape using an extruder and stretching or rolling it in a uniaxial direction. For example, it is preferable that the conveyor belt 10 is long in one direction and that the longitudinal direction of the conveyor belt 10 coincides with the uniaxial direction. The thickness of the core 11 is not particularly limited, but for example, it is 0.2 mm or more and 4.0 mm or less.

[0018] The surface canvas 12 has weft threads and warp threads made of a resin material with a higher melting point than the weft threads. For example, the weft and warp threads are woven in a plain weave, or they may be woven in a twill weave. The thickness of the surface canvas 12 is not particularly limited, but is preferably 0.1 mm or more. The surface canvas 12 is bonded to the core body 11 using an adhesive or by heat pressing.

[0019] The weft threads constituting the surface canvas 12 are made of an aliphatic polyamide such as PA6. Preferably, the weft threads constituting the surface canvas 12 are made of the same material as the core 11, thereby improving the adhesion between the core 11 and the surface canvas 12. If the core 11 is made of PA6, it is preferable that the weft threads constituting the surface canvas 12 are made of PA6. The weft threads constituting the surface canvas 12 are multifilaments. The weft threads constituting the surface canvas 12 may or may not be twisted. By forming the weft threads constituting the surface canvas 12 and the core 11 from the same resin, the adhesion between the surface canvas 12 and the core 11 can be improved.

[0020] The warp threads constituting the surface canvas 12 are made of a resin material with a higher melting point than the weft threads. For the warp threads constituting the surface canvas 12, synthetic resins such as aliphatic polyamides like PA66 (a polyamide obtained by polymerizing hexamethylenediamine and adipic acid), semi-aromatic polyamides like PA6T (a polyamide obtained by polymerizing hexamethylenediamine and terephthalic acid), and fully aromatic polyamides like para-aramid (a polyamide obtained by polymerizing p-phenylenediamine and terephthalic acid) can be used. Regarding the melting points of the above resins, PA6 has a melting point of 220°C, PA66 has a melting point of 264°C, PA6T has a melting point of 306°C, and para-aramid has a melting point of approximately 500°C. The warp threads constituting the surface canvas 12 are multifilaments. The warp threads constituting the surface canvas 12 may or may not be twisted.

[0021] The surface canvas 12 and the back canvas 14 may be treated with resin. Resin treatment may be omitted. The configuration may also consist of either the surface canvas 12 or the back canvas 14 being treated with resin. Resin treatment can be carried out, for example, by coating treatment such as applying an adhesive, or by dipping treatment such as impregnation or immersion. Various adhesives such as isocyanate-based, nylon-based, epoxy-based, urethane-based, and acrylic-based adhesives can be used. Resin treatment can improve the durability and strength of the conveyor belt, such as its abrasion resistance.

[0022] The conductive film 13 is formed by applying a conductive coating agent containing a conductive substance such as carbon.

[0023] The backing canvas 14 has weft and warp threads, and is, for example, a canvas woven in a plain weave, or it may be a canvas woven in a twill weave. The thickness of the backing canvas 14 is not particularly limited, but is preferably 0.1 mm or more. The backing canvas 14 is bonded to the core body 11 using an adhesive or by heat pressing.

[0024] The weft and warp threads constituting the backing canvas 14 are made of an aliphatic polyamide such as PA6, and preferably from the same material as the core 11. The weft and warp threads constituting the backing canvas 14 are multifilaments. The weft and warp threads constituting the backing canvas 14 may or may not be twisted. By forming the weft and warp threads constituting the backing canvas 14 and the core 11 from the same resin, the adhesion between the backing canvas 14 and the core 11 can be improved.

[0025] The conductive coating 15 is similar to the conductive coating 13 and is formed by applying a conductive coating agent containing a conductive substance such as carbon.

[0026] In the conveyor belt 10 of this embodiment, the total thickness of the conveyor belt 10, which includes the core 11, surface canvas 12, conductive coating 13, back canvas 14, and conductive coating 15, is, for example, 0.8 mm or more and 7.0 mm or less.

[0027] The conveyor belt 10 of this embodiment can be preferably applied to the transport of heavy objects such as batteries.

[0028] Preferably, the melting point of the weft threads constituting the surface canvas 12 is lower than the melting point of the portion of the conveyor belt that contacts the conveyor belt 10 with the object being conveyed, and the melting point of the warp threads constituting the surface canvas 12 is equal to or greater than the melting point of the portion of the conveyor belt 10 that contacts the conveyor belt with the object being conveyed. For example, the object being conveyed by the conveyor belt 10 is a pallet containing heavy objects. The pallet is made of resin, and the bottom surface of the pallet contacts the conveyor belt 10. The pallet is made of PA66, for example, the same material as the warp threads constituting the surface canvas 12. By having the melting point of the weft threads constituting the surface canvas 12 lower than the melting point of the resin constituting the pallet, and the melting point of the warp threads constituting the surface canvas 12 equal to or greater than the melting point of the resin constituting the pallet, the amount of wear due to friction and sliding with the object being conveyed can be reduced.

[0029] (Method for manufacturing the conveyor belt 10) The core 11 is formed by extruding a resin material that will become the core 11 into a sheet using an extruder, and then stretching or rolling it in one axial direction. Next, the surface canvas 12 and the back canvas 14 are formed. The surface canvas 12 is formed by weaving, for example, plain weave or twill weave, from weft threads and warp threads made of a resin material with a higher melting point than the weft threads. The back canvas 14 is formed by weaving, for example, plain weave or twill weave, from weft threads and warp threads. Next, the surface of the surface canvas 12 and the back canvas 14, or both, are treated with resin. Resin treatment is optional, but performing resin treatment can increase the durability, such as abrasion resistance, and strength of the conveyor belt. Next, a conductive coating agent is coated on the surface of the surface canvas 12 and the surface of the back canvas 14, for example, by knife coating, to form a conductive film 13 and a conductive film 15. Next, one side of the core 11 is bonded to the back surface of the surface canvas 12, and the other side of the core 11 is bonded to the back surface of the back canvas 14 using adhesive or heat pressing. In this way, the conveyor belt 10 can be manufactured.

[0030] (Operation and effects of the conveyor belt 10) By using a surface canvas 12 having weft threads and warp threads made of a resin material with a higher melting point than the weft threads, the amount of wear due to friction and sliding with the conveyed object is reduced, and when a conductive coating is provided, the conductive substance such as carbon added to the conductive coating makes it easier for heat to be generated, which can suppress wear and a decrease in conductivity.

[0031] By forming the weft threads constituting the surface canvas 12 and the core 11 from the same resin, the adhesion between the surface canvas 12 and the core 11 can be improved, thereby enhancing durability.

[0032] <Example> The surface canvas 12 was a plain weave canvas with a thickness of 0.45 mm, made of PA6 with 72 filaments and twisted weft threads, and made of PA66 with 72 filaments and twisted warp threads. The back canvas 14 was a plain weave canvas with a thickness of 0.35 mm, made of PA6 with 72 filaments and twisted weft and warp threads. A conductive coating agent was supplied to the surface of the surface canvas 12 and the surface of the back canvas 14 to form conductive films 13 and 15. Adhesive was applied to a core body 11 made of PA6 with a thickness of 1.0 mm, and the back surface of the surface canvas 12 was bonded to one side and the back surface of the back canvas 14 to the other side, thereby manufacturing the conveyor belt of Sample 1 according to Example 1 as described above. The conveyor belt of Sample 1 was an endless belt with a thickness of approximately 1.8 mm, a width of 30 mm, and a length of 6083 mm.

[0033] The conveyor belt of Sample 2 according to Example 2 was manufactured in the same manner as the conveyor belt of Sample 1, except that the warp threads constituting the surface canvas 12 were made of PA66, with 72 filaments and twisted, and the surface canvas 12 and the back canvas 14 were subjected to a resin treatment called dipping.

[0034] A comparative example, Sample 3, was manufactured in the same manner as the conveyor belt of Sample 1, except that the weft and warp threads constituting the surface canvas 12 were made of PA6, with 72 filaments, and twisted.

[0035] Figure 2 is a schematic diagram of the sliding test apparatus 20 according to this embodiment. The sliding test apparatus 20 is a device for performing a sliding test on a conveyor belt 21. The sliding test apparatus 20 has a pair of conveyor pulleys 22A and 22B, a support plate 23, and a stopper 24. The sliding surface of the support plate 23 is constructed by coating the surface of an aluminum support with polyethylene resin.

[0036] The sliding test using the sliding test device 20 is performed as follows: A conveyor belt 21 is wrapped around a pair of conveyor pulleys 22A and 22B so that the elongation rate is 2.0%. A support plate 23 is placed below the conveyor belt 21. Five pallets 30 (only one is shown in the drawing) are placed on the conveying surface of the conveyor belt 21. The pallets 30 are made of PA 66, have a box-like structure with a width of 320 mm and a length of 320 mm, and can hold a total of up to 150 kg of conveyed goods 31 inside. The conveyor belt 21 is driven in the direction of arrow A by the drive of the conveyor pulleys 22A and 22B, and the conveyed goods 31 contained in the pallets 30 are conveyed in the direction of arrow A. A stopper 24 is provided on the conveying path, and the conveyor belt 24 stops the conveying of the conveyed goods 31 contained in the pallets 30. Even when the conveyance is stopped by the stopper 24, the conveyor belt 21 continues to be driven, so that the weight of the conveyed object 31 is applied, causing friction to occur as the conveying surface of the conveyor belt 21 slides against the bottom surface of the pallet 30.

[0037] The conveyor belt of Sample 1 was attached to the sliding test apparatus 20, and a total of 150 kg of conveyed goods 31 were placed in five pallets 30. The conveyor belt 21 was driven at a speed of 32.0 m / min, and while stopping the conveyance with a stopper 24, the conveying surface of the conveyor belt 21 was slid between the conveying surface and the bottom surface of the pallets 30 to conduct a sliding test. The test duration of the sliding test was 144 hours. The change in weight of the conveyor belt and the surface electrical resistance [Ω] before and after the sliding test were investigated.

[0038] The conveyor belts of Sample 2 and Sample 3 were also attached to the sliding test apparatus 20 and subjected to sliding tests in the same manner as described above. The test duration for the sliding tests was 144 hours for Sample 2 and 120 hours for Sample 3. As with Sample 1, the change in weight of the conveyor belts before and after the sliding test, and the surface electrical resistance values ​​[Ω] before and after the sliding test were examined. The results are shown in Table 1. Note that the change in weight is shown as a ratio with the change in weight of Sample 3 set to 1.00.

[0039]

[0040] Figure 3 is a graph showing the ratio of the amount of weight change in the above sliding test and the measurement results of the surface electrical resistance values [Ω] before and after the sliding test. In Figure 3, the bar graph shows the ratio of the amount of weight change. Also, the broken-line graph shows the surface electrical resistance value [Ω] before the sliding test, and the solid-line graph shows the surface electrical resistance value [Ω] after the sliding test. As shown in Figure 3, when the amount of weight change of Sample 3 is set to 1.00, the ratio of the amount of weight change of the conveyor belt of Sample 1 is 0.21, and the ratio of the amount of weight change of the conveyor belt of Sample 2 is 0.20, both of which are smaller than the amount of weight change of Sample 3. Also, the conveyor belt of Sample 1 had a surface electrical resistance value of 9.8×10 ３ [Ω] before the sliding test and a surface electrical resistance value of 1.9×10 ４ [Ω] after the sliding test, maintaining a small surface electrical resistance value before and after the sliding test. The conveyor belt of Sample 2 had a surface electrical resistance value of 3.9×10 ５ [Ω] before the sliding test and a surface electrical resistance value of 4.4×10 ５ [Ω] after the sliding test. Although it was larger than the surface electrical resistance value of Sample 1, the change in the surface electrical resistance value before and after the sliding test was as small as that of Sample 1. The conveyor belt of Sample 3 had an electrical resistance value of 1.2×10 ４ [Ω] before the sliding test and an electrical resistance value of 1.0×10 ７ [Ω] or more, which is the measurement upper limit, after the sliding test, and the change in the electrical resistance value before and after the sliding test was large.

[0041] From the above, it was confirmed that according to the conveyor belt of this embodiment, the amount of wear due to friction and sliding with the conveyed object can be reduced, and the decrease in conductivity can be suppressed.

[0042] 10 Belt 11 Core body 12 Surface canvas 13 Conductive coating 14 Back canvas 15 Conductive coating

Claims

1. A conveyor belt comprising: a core; a surface canvas attached to one side of the core; a back canvas attached to the other side of the core; and a conductive coating formed on at least the surface of the surface canvas, wherein the surface canvas comprises weft threads and warp threads made of a resin material with a higher melting point than the weft threads.

2. The conveyor belt according to claim 1, wherein the weft thread is made of the same material as the core.

3. The conveyor belt according to claim 2, wherein the core and the weft are made of aliphatic polyamide, and the warp is made of aliphatic polyamide, semi-aromatic polyamide, or fully aromatic polyamide with a higher melting point than the weft.

4. The conveying belt according to claim 3, wherein the core and the weft are made of PA6, and the warp is made of PA66.

5. The conveyor belt according to claim 1, wherein the melting point of the warp threads is equal to or greater than the melting point of the portion of the conveyor belt that is in contact with the object being conveyed.

6. The conveyor belt according to claim 1, wherein the surface canvas is resin-treated.

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