Method for producing novel air-permeable leather

Abstract

To provide a method for producing an air-permeable leather capable of efficiently forming open pores on leather in a short time, and small in variation of diameters of defective pores (non-open pores) and open pores.SOLUTION: A method for producing an air-permeable leather pertaining to the present invention comprises cooling a laser-emitting device when irradiating with laser from the laser-emitting device while feeding a leather to a roller feeder comprising a feed roll, and an upper roll.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing breathable leather, and more specifically, to a method for producing breathable leather that can efficiently form through holes in leather in a short time while reducing defective holes (non-through holes) and variation in the diameter of the through holes. [Background technology]

[0002] Generally, when shoes are made from leather (natural leather, artificial leather, etc.), the breathability of the leather is very low or non-existent. Therefore, when a user wears the shoes, the humidity inside the shoes remains extremely high, causing them to become stuffy and ultimately becoming a breeding ground for bacterial growth.

[0003] To address this issue, moisture-permeable materials are selected or fine through-holes are formed in the leather.

[0004] As a method for forming minute through holes in leather, for example, Patent Document 1 proposes a technology for forming linear through holes by performing a needle punching process using specified felt needles (Claims, Specification paragraphs 0020-0023).

[0005] Furthermore, Patent Document 2 discloses that a laser in the infrared region (such as a carbon dioxide laser or a YAG laser) is used to form through-holes in artificial leather, thereby imparting high breathability to the artificial leather. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-1192976 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-248644 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in conventional techniques for perforating leather using needle punches, including the technique disclosed in Patent Document 1, the needles can become distorted or broken over time, which can increase the burden of maintenance and inspection, especially when applied to production lines intended for mass production. Furthermore, if the needles become distorted, defects can occur in the perforated holes.

[0008] Furthermore, even in the perforation method using a laser as disclosed in Patent Document 2, since the leather workpiece is perforated in a batch manner, there is still room for improvement in productivity.

[0009] Furthermore, even when through holes are formed using a laser drilling method, defective holes may occur, such as blind holes or holes that are not drilled horizontally in the thickness direction of the leather (i.e., perpendicular to the surface direction) but at an angle.

[0010] Therefore, the inventors conducted extensive research into leather perforation techniques using conventional lasers and discovered that the conventional problems could be solved by irradiating the leather with a cooled laser and by carrying out the perforation process while feeding the leather using a roller feeder.

[0011] In other words, the present invention aims to provide a method for producing breathable leather that can efficiently form through holes in leather in a short amount of time and has little defective holes (non-through holes) and little variation in the diameter of the through holes. [Means for solving the problem]

[0012] The method for producing breathable leather according to the present invention is a method for producing breathable leather in which through holes are formed in leather by a laser irradiated from a laser emission device, The laser projection device is cooled when the laser is irradiated from the laser projection device while the leather is being fed by the roller feeder.

[0013] In the method for producing breathable leather of the present invention, it is preferable to further cool the through-holes while irradiating them with a laser from the laser emitting device. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram illustrating the method for producing breathable leather according to the present invention.

[0015] [Figure 2] Fig. 2(A) is a plan view of breathable leather produced by the breathable leather production method according to the present invention, and Fig. 2(B) is a cross-sectional view taken along line AB of Fig. 2(A).

[0016] [Figure 3] Fig. 3(A) is an enlarged plan view of breathable leather produced by the method for producing breathable leather according to the present invention, and Fig. 3(B) is an enlarged plan view of breathable leather produced by a conventional method.

[0017] [Figure 4] Fig. 4(A) is an enlarged cross-sectional view of breathable leather produced by the method for producing breathable leather according to the present invention, and Fig. 4(B) is an enlarged cross-sectional view of breathable leather produced by a conventional method.

[0018] [Figure 5] FIG. 5 shows the device used in the examples to evaluate the breathability of leather. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, the method for producing breathable leather according to the present invention will be described in detail with reference to the drawings as appropriate.

[0020] The method for producing breathable leather according to the present invention relates to a method for producing breathable leather in which through-holes are formed in leather by a laser irradiated from a laser emission device.

[0021] Here, "leather" refers to natural leather and artificial leather, which may be used alone or in combination. There are no particular limitations on the natural leather, as long as it is obtained by tanning the hides of animals such as cows, horses, and pigs.

[0022] There are no particular limitations on the artificial leather, but examples include those made of a nonwoven fabric layer made of synthetic fibers (e.g., nylon fibers or polyester fibers) soaked in polyurethane resin and a surface resin layer made of polyurethane resin, etc. More specific examples include celluloid leather, PVC leather (vinyl chloride leather), and PU leather (polyurethane leather).

[0023] The leather used in the present invention may be natural leather or artificial leather with a waterproof layer or the like laminated thereon, if necessary.

[0024] In addition, in the method for producing breathable leather of the present invention, as shown by reference numeral 1 in Fig. 1, leather 10 is conveyed by a roller feeder 20 in the direction of arrow X, which is the feed direction, while a laser 31 is irradiated from a laser emitting device 30 to form (perforate) through-holes 50. Here, the laser emitting device 30 operates (irradiates laser) while being cooled by a cooling unit 40.

[0025] With this configuration, the method for producing breathable leather of the present invention can efficiently form through holes in leather in a short time, and aims to provide a method for producing breathable leather with little defective holes (non-through holes) and little variation in the diameter of the through holes.

[0026] Specifically, in the breathable leather obtained by the manufacturing method of the present invention, as shown in Figure 3(A), when viewed in a plane and enlarged, through holes H of approximately the same shape and size are formed, and the distance L1 between the through holes is also constant, whereas in the conventional method, as shown in Figure 3(B), the shapes and sizes of the through holes h1 to h3 are different, and the distances L2 and L3 between the through holes also vary.

[0027] Furthermore, as shown in FIG. 4, which is an enlarged cross-sectional view, the breathable leather obtained by the manufacturing method of the present invention has through-holes H formed in a straight line in the thickness direction (i.e., perpendicular to the surface direction) (FIG. 4(A)), whereas in conventional methods, through-holes are often formed obliquely rather than perpendicularly to the surface direction, as shown by the reference numeral h4, or non-penetrating holes (non-through holes), as shown by the reference numeral h5, which may result in insufficient breathability.

[0028] There are no particular limitations on the roller feeder as long as it uses rollers to feed (transport) leather, but as shown by the reference numeral 20 in Figure 1, it generally consists of a feed reel 22 that is rotated by a motor or the like, and an upper roll (free roller) that sandwiches the leather between the feed reel 22 and allows it to be transported.

[0029] Here, the laser irradiation speed from the laser emitting device and the conveying speed of the roller feeder are not particularly limited and can be adjusted appropriately taking into consideration the density of the through holes, etc. The size of the through holes is generally 0.01 mm to 0.5 mm in diameter, and the density of the through holes is generally 20 to 100 per square centimeter.

[0030] The type of laser is not particularly limited, but examples include CO2 laser, YAG laser, fiber laser, and semiconductor laser.

[0031] During laser irradiation, the laser emission device is cooled by a cooling unit 40. Here, the cooling unit is not particularly limited as long as it is a device that cools the laser emission device, and examples thereof include a water-cooled chiller and a cold air chiller.

[0032] The method for producing breathable leather according to the present invention produces breathable leather with numerous through-holes formed in it, as shown in Fig. 2(A) (plan view) and Fig. 2(B) (AB cross-sectional view). In this breathable leather, the through-holes are formed in the thickness direction D1, approximately perpendicular to the surface direction D2.

[0033] Furthermore, from the viewpoint of further reducing the occurrence of defective holes, it is preferable to cool the through holes while irradiating them with a laser from the laser emitting device. Specifically, it is desirable to cool the through holes immediately after they are formed by laser irradiation or while they are being irradiated with a laser. Examples of the cooling device include a water-cooled chiller and a cold air chiller, as described above. [Example]

[0034] The method for producing the breathable leather of the present invention will be described in more detail below with reference to examples, but the technical scope of the present invention is not limited thereto.

[0035] [Example 1] A laser irradiation device (KH866A laser micro-hole processing line manufactured by Wenzhou Kanghong Machinery Co., Ltd., laser: CO2 laser) was prepared, and a roller feeder was installed to transport the leather to the laser irradiation section, and a water-cooled cooling section was also installed to cool the laser irradiation section, resulting in laser irradiation device 1.

[0036] Next, the leather (polyurethane leather) was fed to a roller feeder and continuously irradiated with laser in a laser irradiation section while being cooled in a water-cooled cooling section.

[0037] The obtained polyurethane leather with through holes was cut and formed into a square shape (20 cm on a side) to prepare test leather 1, which was subjected to evaluation tests 1 and 2. The evaluation results are shown in Table 1.

[0038] [Evaluation test] 1. Evaluation test 1 (breathability test) A breathability testing device was prepared as shown in Figure 5. Here, the breathability testing device is composed of a bottom syringe T2 with only the top side open and a top syringe T1 with both bottom sides open. The bottom syringe T2 is connected to an air blower B via a rubber tube, and air is sent to the bottom syringe T2 by compressing the air blower B.

[0039] The test leather obtained in each example or comparative example was sandwiched between the lower syringe T2 and the upper syringe T1 as shown by the number L in Figure 5, and the lower syringe T2 and the upper syringe T1 were tightly attached to each other with a clamp.

[0040] Furthermore, after water was poured into the upper syringe T1, air was sent to the lower syringe T2 using the blower B. At this time, the state of the air bubbles in the water of the upper syringe T1 was observed through the test leather L, and evaluated based on the following evaluation criteria.

[0041] [Evaluation criteria] ◯: Uniform fine bubbles were generated (excellent breathability). △: Uneven bubbles were generated (breathability was uneven). ×: No bubbles were generated (no breathability).

[0042] 2. Evaluation test 2 (quality test) The plan and cross sections of the test leather were observed using a microscope to observe the shapes of the 20 through holes and the distance between the 20 through holes, and the quality was evaluated according to the following criteria.

[0043] [Evaluation criteria] ◯: Of the 20 through holes, 16 or more through holes had almost the same shape and shape, and of the 20 through holes, 16 or more through holes had the same distance between them. △: Of the 20 through holes, 10 to 15 through holes had almost the same shape and shape, and of the 20 through holes, 10 to 15 through holes had the same distance between them. ×: Of 20 through holes, 9 or less through holes had almost the same shape and shape, and of 20 through holes, 9 or less through holes had the same distance between them.

[0044] [Comparative Example 1] A laser irradiation device 2 was configured in the same manner as the laser irradiation device 1, except that a water-cooling type cooling unit for cooling the laser irradiation unit was not provided. Next, test leather 2 was prepared in the same manner as in Example 1, except that laser irradiation device 2 was used instead of laser irradiation device 1, and subjected to evaluation tests 1 and 2. The evaluation results are shown in Table 1.

[0045] Comparative Example 2 Laser irradiation device 3 was configured in the same manner as laser irradiation device 1, except that the leather was left stationary and laser irradiation was performed without installing a roller feeder to transport the leather to the laser irradiation section. Next, test leather 3 was prepared in the same manner as in Example 1, except that laser irradiation device 3 was used instead of laser irradiation device 1, and subjected to evaluation tests 1 and 2. The evaluation results are shown in Table 1.

[0046] Comparative Example 3 Leather (polyurethane leather) was cut and formed into a square shape (20 cm on a side) to prepare test leather 4, which was subjected to evaluation test 1. The evaluation results are shown in Table 1.

[0047] [Table 1]

[0048] As shown in Table 1, compared to test leather 4 (Comparative Example 3) in which no through holes were formed, test leathers 2 and 3 in which through holes were formed by laser had improved breathability and quality of the through holes (Comparative Examples 1 and 2).

[0049] However, in the breathability test of test leathers 2 and 3, non-uniform bubbles were observed, resulting in variations in breathability (breathability test). The shapes of the through holes were not consistent both in plan and cross section, and there were also areas with different sizes and blind holes, indicating that there was room for improvement in terms of quality.

[0050] On the other hand, in the breathability test of test leather 1, uniform fine bubbles were generated, indicating extremely good breathability, and in the quality test, the distance between the through holes and the shape of the through holes were almost identical, and no blind holes were observed.

[0051] From the above, it can be seen that the breathability and quality of the through holes of test leather 1 can be improved by using a cooling unit and a roller feeder. [Explanation of symbols]

[0052] 1: Method for producing breathable leather according to the present invention 10:Leather 20: Roller feeder 21: Upper roll 22: Feed roll 30: Laser irradiation unit 31: Laser 40: Cooling section 50:Through hole X: Feed direction D1: Thickness direction D2: Surface direction H, h1~h4: Through hole h5: Impenetrable hole L1~L3: Distance between through holes T1: Top syringe T2: Lower syringe W:Water B: Air blower

Claims

1. A method for producing breathable leather by forming through holes in leather using a laser irradiated from a laser emission device, A method for producing breathable leather, characterized in that the laser projection device is cooled when a laser is irradiated from the laser projection device while the leather is fed by a roller feeder consisting of a feed roll and an upper roll.

2. 2. The method for producing breathable leather according to claim 1, further comprising cooling the through-holes while irradiating the laser from the laser emitting device.

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