conveyor belt

Abstract

Conveyor belt 10, comprising: a tape core body 14; and a cover rubber 12 covering the tape core body 14, wherein the cover rubber 12 has a fine ridge / groove structure formed on at least a portion of a surface thereof, wherein the fine ridge / groove structure is formed by pressing the metal plates 32 having the fine ridge / groove structure on at least one surface against the surface of the cover rubber 12, and wherein the cover rubber 12 has a surface roughness of 1 µm or more and 12 µm or less, a sharpness of 2 or more and 9 or less, and a specular gloss at an incident angle of 60° of 0.1 or more and 10 or less due to the fine ridge / groove structure.

Description

Technical area

[0001] The present invention relates to a conveyor belt. State of the art

[0002] In the prior art, belt conveyor devices for transporting objects to be conveyed, such as coal, ore, gravel, and the like, are widely used in mines, construction sites, and the like. For example, Patent Document 1 below discloses the production of a conveyor belt that, while offering excellent appearance, has excellent running stability regardless of the application environment, and has excellent resistance to bending deformation. These are unvulcanized rubber molded articles having a fabric laminated on surfaces thereof corresponding to the conveying and non-conveying surfaces of the conveyor belt, pressed with a pair of upper and lower heating plates to transfer the texture pattern of the fabric to each surface, and peeling the fabric from the conveyor belt formed after vulcanization.

[0003] In Patent Document 1 below, the surface roughness of the conveyor belt is described as being from 1 µm to 15 µm, and more preferably from 1 µm to 7 µm. Patent Document 2 discloses a seamless belt comprising an endless belt body having a conveying plane, and a surface roughness Rz of the conveying plane is set to be higher than 6 µm and lower than 20 µm. Patent Document 3 discloses a product surface containing a first optoelectronically readable code formed by an array of planar cells of a first and a second cell type. The cells, as an integral part of the surface, have a surface profile. Due to the design of the surface profiles, an intensity difference between the intensity reflected by the surface profile of the second cell type and the intensity reflected by the surface profile of the first cell type arises upon incident light. The surface has a second code.The maximum of the absolute intensity difference of the first code lies in a different reflection direction than the maximum of the absolute intensity difference of the second code. List of citationsPatent literature Patent document 1: JP 2010 - 195 586 A Patent document 2: JP 2017- 45 401 A Patent document 3: US 2016 / 0 239 734 A1 Brief description of the inventionTechnical problem

[0004] In rubber products such as conveyor belts, a phenomenon known as blooming may occur on the surface during the storage period from the time the product is manufactured until it is used. Blooming is a phenomenon in which a wax or anti-aging agent formulated to prevent rubber degradation migrates to the surface of the rubber. Although it does not affect the rubber's performance, it causes deterioration in the product's appearance. In other words, a product that is actually new and has no performance issues may be identified as having deteriorated performance if the conveyor belt has a poor appearance.

[0005] Although the aforementioned document mentions poor appearance due to bumps and cracks on the belt surface, the bloom coating was not taken into consideration, and thus there is potential for improvement.

[0006] In view of the foregoing, it is an object of the present invention to provide a conveyor belt which is not susceptible to having a poor appearance due to blooming. Solution to the problem

[0007] In order to achieve the above-described object, a conveyor belt according to the present invention includes: a belt core body and a cover rubber covering the belt core body, wherein the cover rubber has a fine ridge / groove structure formed on at least a portion of a surface thereof, wherein the fine ridge / groove structure is formed by pressing the metal plates having the fine ridge / groove structure on at least one surface against the surface of the cover rubber, and wherein the cover rubber has a surface roughness of 1 µm or more and 12 µm or less, a sharpness of 2 or more and 9 or less, and a specular gloss at an incident angle of 60° of 0.1 or more and 10 or less due to the fine ridge / groove structure. Advantageous effects of the invention

[0008] According to the present invention, the fine ridge / groove structure formed on the surface of the conveyor belt causes light to be diffusely reflected, making it difficult to detect color differences on the surface of the conveyor belt. As a result, bloom deposits generated on the conveyor belt surface over a storage period from immediately after vulcanization are less noticeable, which is advantageous for maintaining a good appearance of the conveyor belt. In addition, since a fine ridge / groove structure is formed on the conveyor belt surface, scratches caused by use of the conveyor belt are less noticeable, which is advantageous for maintaining a good appearance of the conveyor belt even after use begins. Furthermore, since the fine ridge / groove structure improves releasability during vulcanization of the conveyor belt, it is advantageous for improving the productivity of the conveyor belt. Brief description of the drawings Fig. 1 is an explanatory diagram illustrating a configuration of a conveyor belt 10 according to an embodiment. Fig. 2 is an explanatory diagram schematically illustrating a method of manufacturing the conveyor belt 10. Fig. Figure 3 is a table illustrating evaluation results for conveyor belts with different surface properties. Description of embodiments

[0009] A conveyor belt according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0010] Fig. 1 is an explanatory diagram illustrating a configuration of a conveyor belt 10 according to an embodiment. Fig. Fig. 1A is a perspective view illustrating a state in which the conveyor belt 10 is used, and Fig. Figure 1B is a cross-sectional view of the conveyor belt 10 along AA.

[0011] The conveyor belt 10 is used in a belt conveyor system 20 which includes a drive roller 22, a driven roller 24 and the conveyor belt 10 wound thereon.

[0012] The belt conveyor system 20 loads a conveyed object onto the conveyor belt 10 and moves the conveyed object by moving the conveyor belt 10 in the direction of the arrow using the drive roller 22 and the driven roller 24.

[0013] As in Fig. As illustrated in Figure 1B, the conveyor belt 10 includes a belt core body 14 in which a plurality of canvases are layered, and a cover rubber 12 covering the belt core body 14. Various known materials can be used as the canvases constituting the belt core body 14, including organic fibers such as nylon fibers, polyester fibers, and aramid fibers.

[0014] The cover rubber 12 includes edge rubber layers 1202, an upper surface cover rubber layer 1204, and a lower surface cover rubber layer 1206.

[0015] The edge rubber layers 1202 are respectively arranged on both sides of the tape core body 14 in the width direction.

[0016] The edge rubber layers 1202 are portions that protect both sides of the conveyor belt 10 including the belt core body 14 in the width direction.

[0017] The upper surface cover rubber layer 1204 and the lower surface cover rubber layer 1206 cover the tape core body 14 and the edge rubber layers 1202.

[0018] The cover rubber layer of the upper surface 1204 is a portion onto which a conveyed object is loaded and conveyed, and the cover rubber layer of the lower surface 1206 is a portion that comes into contact with the rollers (drive roller 22, driven roller 24) that support the conveyor belt 10.

[0019] The cover rubber 12 (edge rubber layers 1202, upper surface cover rubber layer 1204, lower surface cover rubber layer 1206) and the belt core body 14 each extend with a constant width and form the conveyor belt 10.

[0020] Here, the inventors of the present invention have found, as a result of diligent research, that by forming a fine ridge / groove structure on the surface of the cover rubber 12 and adjusting the surface properties within the ranges described below, the blooming produced during the storage period becomes less noticeable.

[0021] In other words, the cap rubber 12 has a fine ridge / groove structure formed on at least a portion of a surface thereof, and has a surface roughness of 1 μm or more and 12 μm or less, a sharpness of 2 or more and 9 or less, and a specular gloss at an incident angle of 60° of 0.1 or more and 10 or less due to the fine ridge / groove structure. More preferably, the cap rubber 12 has a surface roughness of 2 μm or more and 5 μm or less, a sharpness of 3 or more and 5 or less, and a specular gloss at an incident angle of 60° of 0.1 or more and 3 or less due to the fine ridge / groove structure.

[0022] At least a portion of the surface of the cover rubber 12 means, for example, only the surface of the upper surface cover rubber layer 1204 (the surface on the opposite side to the tape core body 14), only the surface of the lower surface cover rubber layer 1206, only the surfaces of the edge rubber layers 1202, only the surfaces of the upper surface cover rubber layer 1204 and the edge rubber layers 1202, and the like; however, this naturally also includes a case where a fine ridge / groove structure is formed on the entire surface of the cover rubber 12 (that is, the surfaces of the upper surface cover rubber layer 1204, the lower surface cover rubber layer 1206, and the edge rubber layers 1202).

[0023] The surface roughness Ra is the arithmetic mean of the roughness specified in JIS B 0601:2001 and is a parameter that can be evaluated by averaging surface conditions. In the present embodiment, the surface roughness of the cover rubber surface was measured using a VK-X 150 laser microscope available from Keyence.

[0024] The kurtosis (Rku) is a numerical value indicating the degree of sharpness of a probability density function of a contour line specified in JIS B 0601:2001. In the present embodiment, the degree of sharpness of the cover rubber surface was measured using the VK-X 150 laser microscope available from Keyence.

[0025] The specular glossiness Gs is obtained by measuring the specular reflection flux φs from a sample surface with respect to incident light for which an incident angle θ is defined, and the measurement method is specified in JIS Z 8741: 1997. In the present embodiment, the specular glossiness was measured at an incident angle of 60° (Method 3: Gs (60°)) using Picogloss 500MC available from Erichsen.

[0026] Fig. 2 is an explanatory diagram schematically illustrating a method of manufacturing the conveyor belt 10.

[0027] The conveyor belt 10 is subjected to vulcanization treatment after the cover rubber 12, which is unvulcanized, and the belt core body 14 are laminated together. The vulcanization treatment of the conveyor belt 10 is performed by applying heat and pressure by pressing hot thick plates 30 against the upper and lower surfaces of the cover rubber 12 (the surfaces of the upper surface cover rubber layer 1204 and the lower surface cover rubber layer 1206). At this time, metal plates 32 (for example, approximately 10 mm thick) with a fine ridge / groove structure formed on one surface thereof are each interposed between a corresponding one of the thick plates 30 and the cover rubber 12, and the fine ridge / groove structure is transferred to the surface of the cover rubber 12.The metal plates 32 have the fine ridge / groove structure formed thereon, and at least the surface on the side to be in contact with the cover rubber 12 is subjected to a blasting treatment.

[0028] In other words, in the present embodiment, when the conveyor belt 10 is manufactured, during the vulcanization of the cover rubber 12, the metal plates 32 having the fine ridge / groove shape formed on a surface thereof by a blasting treatment are brought into contact with at least a portion of the surface of the cover rubber 12, and the surface roughness, sharpness, and mirror gloss of the surface of the cover rubber 12 are made by transferring the fine ridge / groove shape thereto.

[0029] It should be noted that in Fig. 2 the metal plates 32 and the thick plates 30 are pressed from the upper direction and the lower direction of the cover rubber 12, however, when the fine ridge / groove shape is formed in the edge rubber layers 1202, the metal plates 32 and the thick plates 30 are pressed against the surfaces of the edge rubber layers 1202 from the sides of the cover rubber 12.

[0030] Furthermore, the method for forming the surface characteristics of the cover rubber 12 is not limited to the above. For example, a fine ridge / groove shape may be formed and transferred to surfaces of the thick plates 30, or a resin plate having a fine ridge / groove structure formed on a surface thereof may be used instead of the metal plates 32. In addition, a woven fabric or a knitted fabric having a fine ridge / groove structure on a surface thereof may be used instead of the metal plates 32.

[0031] On the other hand, the metal plates 32 have the features of high heat resistance of the material itself, good releasability due to low surface energy, easy processing by shot blasting, easy replacement when the fine ridge / groove structure deteriorates due to repeated use, and reusability by performing the shot blasting again, and it is particularly preferable to transfer the fine ridge / groove structure using the metal plates 32 as in the present embodiment. Examples

[0032] Examples of the conveyor belt according to the present invention will be described below.

[0033] Fig. Figure 3 is a table showing evaluation results of conveyor belts with different surface properties.

[0034] In the present example, for conveyor belts having different surface roughnesses, degrees of sharpness, and degrees of specular gloss at an incident angle of 60°, releasability from the metal plates 32 at the end of vulcanization (hereinafter referred to simply as "releasability"), the visually observed state (appearance) of the surface immediately after vulcanization, and the visually observed state of the surface after six months of storage in an indoor environment after vulcanization were evaluated.

[0035] It should be noted that the meanings of the terms indicating evaluation results of the visually observed condition are as follows. Good: Uniform gloss is observed throughout and no partial clouding is observed. Fair: Partial white opacity is observed in a few areas, but there are no appearance problems. Poor: Partial white opacity is observed in many areas, and there are appearance problems. Very bad: White cloudiness everywhere and there are problems with the appearance.

[0036] As evaluation criteria, Good and Fair meant that the test was passed, and Poor and Very Poor meant that it was failed.

[0037] It should be noted that the “white cloudiness” mentioned above is a case where a bloom coating is visible.

[0038] In the Fig.In the table illustrated in Figure 3, parameters that do not correspond to the numerical ranges of the surface properties of the conveyor belt according to the invention are shaded, ie, a surface roughness of 1 or more and 12 or less, a sharpness of 2 or more and 9 or less, and a specular gloss at an incident angle of 60° of 0.1 or more and 10 or less. In addition, the evaluation items that are considered to be failed are indicated by hatching.

[0039] Comparative Example 1 is a conveyor belt with a surface roughness of 14 µm, a sharpness of 10, and a specular gloss of 0.05. In Comparative Example 1, although the releasability was good, the visually observed condition immediately after vulcanization was poor, and the visually observed condition after six months of storage of the conveyor belt was very poor.

[0040] Comparative Example 2 is a conveyor belt formed with a surface roughness of 0.5 µm, a sharpness of 1, and a specular gloss of 11. In Comparative Example 2, the adhesion at the time of peeling was strong, the visually observed condition immediately after vulcanization was poor, and the visually observed condition after six months of storage of the conveyor belt was very poor. Comparative Example 3 is a conveyor belt having a surface roughness of 6 µm, a sharpness of 1, and a specular gloss of 8. In Comparative Example 3, some adhesion was observed at the time of peeling. In addition, the visually observed condition immediately after vulcanization was good, but the visually observed condition after six months of storage of the conveyor belt was poor.

[0041] Next, conveyor belts corresponding to the number ranges described above are considered as examples.

[0042] Example 1 is a conveyor belt with a surface roughness of 1 µm, a sharpness of 2, and a specular gloss of 0.1. In Example 1, there were no releasability issues; the visually observed condition immediately after vulcanization was good, and the visually observed condition after six months of storage of the conveyor belt was also good.

[0043] Example 2 is a conveyor belt that has a surface roughness of 2 µm, a sharpness of 3, and a specular gloss of 0.1. In Example 2, the releasability was good, the visually observed condition immediately after vulcanization was good, and the visually observed condition after six months of storage of the conveyor belt was also good. Example 3 is a conveyor belt that has a surface roughness of 5 µm, a sharpness of 5, and a specular gloss of 3. In Example 3, the releasability was good, the visually observed condition immediately after vulcanization was good, and the visually observed condition after six months of storage of the conveyor belt was also good.

[0044] Example 4 is a conveyor belt that has a surface roughness of 12 µm, a sharpness of 9, and a specular gloss of 10. In Example 4, there were no problems with releasability, the visually observed condition immediately after vulcanization was good, and the visually observed condition after six months of storage of the conveyor belt was fair.

[0045] Considering these comparative examples and examples regarding releasability, as illustrated in Comparative Example 2, it is believed that when the surface roughness and sharpness are small (height distribution is reduced), and the specular gloss is high, air does not easily penetrate between the metal plate and the conveyor belt surface at the time of peeling, adhesion increases, and releasability decreases. When the releasability is low, it takes time for the conveyor belt to peel, and productivity decreases, which is not preferable.

[0046] In addition, from the visually observed state, when the surface roughness and sharpness are high and the mirror gloss is low, a white haze is visible on the conveyor belt surface, resulting in a poor appearance. In particular, six months after vulcanization, the area where haze occurs increases due to the appearance of bloom.

[0047] On the other hand, the conveyor belts corresponding to the numerical ranges of the conveyor belt according to the present invention maintained a good appearance even six months after vulcanization.

[0048] In other words, a conveyor belt having a cover rubber with a surface roughness of 1 μm or more and 12 μm or less, a sharpness of 2 or more and 9 or less, and a specular gloss at an incident angle of 60° of 0.1 or more and 10 or less showed no problems with releasability, and the appearance was maintained above a level where there were no problems with appearance after being stored for six months immediately after vulcanization.

[0049] In particular, a conveyor belt having a surface roughness of 2 µm or more and 5 µm or less, a sharpness of 3 or more and 5 or less, and a specular gloss at an incident angle of 60° of 0.1 or more and 3 or less had good releasability and maintained a good appearance after six months of storage immediately after vulcanization.

[0050] As described above, according to the conveyor belt of the present invention, by forming a fine ridge / groove structure having surface characteristics within the protruding ranges on the surface of the conveyor belt (cover rubber), diffuse reflection of light occurs, and color differences on the surface of the conveyor belt become difficult to detect. As a result, blooming that occurs on the surface of the conveyor belt immediately after vulcanization and over the storage period becomes less noticeable, which is advantageous in maintaining a good appearance of the conveyor belt.

[0051] In addition, due to the fine ridge / groove structure, scratches caused by the use of the conveyor belt are less noticeable, which is beneficial in terms of maintaining a good appearance of the conveyor belt even after the start of use.

[0052] Since the fine ridge / groove structure improves the releasability during vulcanization of the conveyor belt, it is also beneficial for improving the productivity of the conveyor belt. List of reference symbols 10 Conveyor belt 12 cover rubber 1202 edge rubber layer 1204 Top surface rubber layer 1206 Cover rubber layer of the lower surface 14 tape core bodies 20 Belt conveyor system

Claims

[1] Conveyor belt 10, comprising: a tape core body 14; and a cover rubber 12 covering the tape core body 14, wherein the cover rubber 12 has a fine ridge / groove structure formed on at least a portion of a surface thereof, wherein the fine ridge / groove structure is formed by pressing the metal plates 32 having the fine ridge / groove structure on at least one surface against the surface of the cover rubber 12, and wherein the cover rubber 12 has a surface roughness of 1 µm or more and 12 µm or less, a sharpness of 2 or more and 9 or less, and a specular gloss at an incident angle of 60° of 0.1 or more and 10 or less due to the fine ridge / groove structure. [2] Conveyor belt 10 according to claim 1, wherein the cover rubber 12 has a surface roughness of 2 µm or more and 5 µm or less, a sharpness of 3 or more and 5 or less, and a mirror gloss at an incident angle of 60° of 0.1 or more and 3 or less due to the fine ridge / groove structure.

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