Leather product

Abstract

To provide a leather fabric formed so as to have good appearance by making continuous sewing machine stitches by lock stitch sewing on a surface using relatively thick multifilament yarn.SOLUTION: A leather product is formed by making sewing machine stitches by lock stitch sewing on a leather fabric, and has a first yarn constituting the sewing machine stitches on a first surface on the front side of the leather fabric, and a second yarn constituting the sewing machine stitches on a second surface on the rear side of the leather fabric. Thickness of the leather fabric is 2 to 12 millimeters. The first yarn and the second yarn are multifilament yarns. Thickness of the first yarn is 1600 to 4000 dtex and thicker by 600 dtex or more than the second yarn. Thickness of the second yarn is 1000 to 1800 dtex. Knot between the first yarn and the second yarn is located closer to a second surface in a thickness direction of the leather fabric.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] This specification discloses technology relating to leather products and manufacturing methods thereof. [Background technology]

[0002] Leather products made by sewing machine stitches onto leather fabric (including natural leather, synthetic leather, and artificial leather) are used for various items that are visible to the human eye, such as automobile interior parts, furniture, bags, etc. Patent Document 1 describes an automobile interior part made by sewing machine stitches onto leather fabric. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-198943 A Summary of the Invention [Problem to be solved by the invention]

[0004] When sewing leather fabric with a machine stitch using a relatively thick multifilament thread of about 1600 to 4000 decitex (5 to 0 count in product count), there is a problem that the upper and lower threads tend to become loose in places along the stitch, making it difficult to obtain a continuous, attractive seam. [Means for solving the problem]

[0005] The technology disclosed in this specification can be realized in the following forms.

[0006] A method for manufacturing a leather product in one embodiment disclosed in the present specification is a method for manufacturing a leather product in which a sewing machine stitch is sewn to a leather fabric by a lock stitch. The method includes a thread preparation step of preparing an upper thread and a lower thread for a sewing machine, a placing step of placing the leather fabric on a needle plate of the sewing machine with the back surface of the leather fabric facing up, and a sewing step of forming the sewing machine stitch on the leather fabric by lock stitching the leather fabric placed on the needle plate using the sewing machine in which the upper thread and the lower thread are prepared. The thickness of the leather fabric is 2 to 12 mm. The upper thread and the lower thread are multifilament threads. The thickness of the upper thread is 1000 to 1800 decitex. The thickness of the lower thread is 1600 to 4000 decitex, which is 600 decitex or more thicker than the upper thread. In the thread preparation step, the tension of the upper thread is adjusted to 15 to 21 Newtons, and the tension of the lower thread is adjusted to 1 to 2 Newtons. According to this embodiment of the method for manufacturing leather products, a sewing machine stitch can be formed continuously and attractively on the surface of the leather fabric using a relatively thick multifilament thread of 1600 to 4000 decitex.

[0007] A leather product in one embodiment disclosed in the present specification is a leather product in which a machine stitch is sewn to a leather fabric by a lock stitch. The leather product includes a first thread constituting the machine stitch on a first surface of the front side of the leather fabric, and a second thread constituting the machine stitch on a second surface of the back side of the leather fabric. The thickness of the leather fabric is 2 to 12 mm. The first thread and the second thread are multifilament threads. The thickness of the first thread is 1600 to 4000 decitex, which is 600 decitex or more thicker than the second thread. The thickness of the second thread is 1000 to 1800 decitex. A knot of the first thread and the second thread is located near the second surface in the thickness direction of the leather fabric. According to this type of leather product, the quality of the machine-sewn lock stitch using a relatively thick multifilament thread of 1600 to 4000 decitex can be improved.

[0008] The technology disclosed in this specification can be realized in various forms other than leather products and their manufacturing methods, for example, in the form of automobile interior parts, furniture, bags, etc., using leather products. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view showing a leather product of the present embodiment. [Diagram 2] FIG. 1 is a cross-sectional view showing a leather product of the present embodiment. [Diagram 3] FIG. 1 is a process diagram showing a method for manufacturing a leather product. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Fig. 1 is a plan view showing a leather product 10 of this embodiment. Fig. 2 is a cross-sectional view showing the leather product 10 of this embodiment. The cross-sectional view of Fig. 2 shows the cross section F2-F2 of Fig. 1.

[0011] The leather product 10 is a product in which a sewing machine stitch 200 is sewn onto a leather fabric 100. The leather product 10 can be used for various items that are visible to the human eye, such as automobile interior parts, furniture, and bags.

[0012] The leather fabric 100 of the leather product 10 is a sheet-like leather. The leather fabric 100 is in the form of a sheet having a front surface 110 and a back surface 120. The front surface 110 is a first surface that is the front side that is visible to the human eye when the leather product 10 is used as a final product. The back surface 120 is the surface opposite to the front surface 110. The back surface 120 is a second surface that is the back side that is not visible to the human eye when the leather product 10 is used as a final product.

[0013] In this embodiment, the leather fabric 100 is synthetic leather bonded with urethane foam. In this embodiment, the front surface 110 is formed of synthetic leather, and the back surface 120 is formed of urethane foam. In other embodiments, the leather fabric 100 may be artificial leather or natural leather. In other embodiments, the leather fabric 100 may be leather bonded with a material different from the urethane foam (e.g., woven fabric, nonwoven fabric, etc.), or may be leather with no other material bonded thereto.

[0014] From the viewpoint of forming the sewing stitches 200 continuously and attractively on the surface 110 of the leather material 100, the thickness T of the leather material 100 is preferably 2 mm (millimeters) or more and 12 mm or less.

[0015] The leather fabric 100 has a plurality of needle holes 130 penetrating from the front surface 110 to the back surface 120. The needle holes 130 are formed by a sewing needle (not shown) when sewing the sewing stitches 200 into the leather fabric 100. The needle holes 130 hold the sewing stitches 200.

[0016] The sewing stitch 200 of the leather product 10 is a lock stitch sewn into the leather fabric 100 by a sewing machine (not shown). The sewing stitch 200 includes a front surface thread 210 and a back surface thread 220. The front surface thread 210 is a first thread that constitutes the sewing stitch 200 on the front surface 110 of the leather fabric 100. The back surface thread 220 is a second thread that constitutes the sewing stitch 200 on the back surface 120 of the leather fabric 100.

[0017] The sewing machine stitch 200 has a knot 230 between the front surface thread 210 and the back surface thread 220 in each of the multiple needle holes 130 in the leather fabric 100. The knot 230 is located closer to the back surface 120 in the thickness direction of the leather fabric 100.

[0018] The sewing pitch P of the sewing machine stitches 200, which is also the distance between two adjacent needle holes 130, is a constant distance. From the viewpoint of forming the sewing machine stitches 200 continuously and attractively on the surface 110 of the leather fabric 100, it is preferable that the sewing pitch P is 4.0 mm or more and 6.0 mm or less.

[0019] The surface thread 210 and the back thread 220 of the sewing machine stitch 200 are multifilament threads. In this embodiment, the surface thread 210 and the back thread 220 are multifilament threads made of polyester. In other embodiments, the surface thread 210 and the back thread 220 may be made of nylon or silk, or may be blended yarns or mixed fiber yarns. The material of the surface thread 210 may be different from that of the back thread 220.

[0020] From the viewpoint of forming the sewing stitches 200 continuously and attractively on the surface 110 of the leather fabric 100, it is preferable that the thickness of the surface thread 210 is 1600 dtex (decitex) or more and 4000 dtex or less (5 to 0 count in product number), which is 600 dtex or more thicker than the back thread 220. Furthermore, it is preferable that the thickness of the back thread 220 is 1000 dtex or more and 1800 dtex or less (8 to 5 count in product number).

[0021] 3 is a process diagram showing a manufacturing method of the leather product 10. When manufacturing the leather product 10, first, an operator performs a thread preparation process (process P110). In the thread preparation process (process P110), an operator prepares an upper thread and a lower thread for a sewing machine. The operator assembles a multifilament thread that will become the back surface thread 220 as an upper thread into the sewing machine. Depending on the thickness of the upper thread, the size of the sewing machine needle is preferably 18 to 24. The operator assembles a multifilament thread that will become the surface thread 210 as a lower thread into the sewing machine.

[0022] In the thread preparation process (process P110), the worker adjusts the tension of the upper thread to 15 to 21 newtons. When measuring the tension of the upper thread, the worker attaches the upper thread, which is passed through the sewing machine balance pin at the upper limit position, to a tension gauge. After that, the worker pulls out the upper thread horizontally 100 mm from the sewing machine balance pin to the left side of the sewing machine. After that, the worker pulls the upper thread horizontally with the tension gauge at 50 mm per second, and measures the value on the tension gauge at that time as the tension of the upper thread.

[0023] In the thread preparation process (process P110), the worker adjusts the tension of the lower thread to 1 to 2 Newtons. When measuring the tension of the lower thread, the worker attaches the lower thread pulled out from the bobbin onto the needle plate to a tension gauge. After that, the worker pulls out the lower thread horizontally 100 mm from above the needle plate to the back of the sewing machine. After that, the worker uses the tension gauge to pull the lower thread horizontally at 50 mm per second, and measures the value of the tension gauge at that time as the tension of the lower thread.

[0024] After performing the thread preparation step (step P110), the worker performs the placement step (step P120). In the placement step (step P120), the worker places the leather fabric 100 on the needle plate of the sewing machine with the back surface 120 of the leather fabric 100 facing up. In other words, the worker places the leather fabric 100 on the needle plate of the sewing machine with the front surface 110 of the leather fabric 100 facing the needle plate.

[0025] After carrying out the placing step (step P120), the worker carries out the sewing step (step P130). In the sewing step (step P130), the worker uses a sewing machine with an upper thread and a lower thread prepared to lock stitch the leather fabric 100 placed on the needle plate, thereby forming sewing machine stitches 200 on the leather fabric 100. In this way, the leather product 10 is completed.

[0026] The applicant conducted an evaluation test of forming machine stitches on leather fabric under the following conditions: <Leather fabric> Various leather fabrics with thicknesses between 2mm and 12mm (including natural leather, synthetic leather and artificial leather). <Sewing thread> Various part numbers of Toyobo Ester Sewing Thread G manufactured by FTC Co., Ltd. <Sewing machine> JUKI Corporation industrial sewing machine LU2-4410-B1T-BF-CS

[0027] The results of this evaluation test showed that when the leather product 10 is manufactured under the conditions of the manufacturing method shown in Fig. 2, the sewing machine stitch 200 can be formed continuously and attractively on the front surface 110 of the leather fabric 100. In the leather product 10 obtained in this way, the knot 230 of the front surface thread 210 and the back surface thread 220 is located closer to the back surface 120 than the center of the leather fabric 100 in the thickness direction due to the relationship of the tension between the upper thread and the lower thread during sewing.

[0028] According to the manufacturing method of the leather product 10 in the embodiment described above, the machine stitches 200 can be continuously and attractively formed on the surface 110 of the leather fabric 100 by lock stitching using a relatively thick multifilament thread of 1600 to 4000 dtex. Also, according to the leather product 10 of the present embodiment, the quality of the machine stitches 200 by lock stitching using a relatively thick multifilament thread of 1600 to 4000 dtex can be improved.

[0029] The technology disclosed in this specification is not limited to the above-mentioned embodiment, example, and modification, and can be realized in various configurations without departing from the spirit thereof. For example, among the technical features in the above-mentioned embodiment, example, and modification, those corresponding to the technical features in each form described in the Summary of the Invention column can be appropriately replaced and combined in order to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. In addition, technical features that are not described as essential in this specification can be appropriately deleted. [Explanation of symbols]

[0030] 10...Leather products 100...Leather fabric 110…Surface 120…Back side 130...needle hole 200…Sewing machine stitch 210…Surface thread 220…Backside thread 230…Knot

Claims

1. A method for manufacturing a leather product in which machine stitches are sewn onto leather fabric, comprising the steps of: a thread preparation step of preparing an upper thread and a lower thread for a sewing machine; a placing step of placing the leather fabric on a needle plate of the sewing machine with the back surface of the leather fabric facing up; a sewing process of forming the sewing machine stitches on the leather fabric by sewing the leather fabric placed on the needle plate with a lock stitch using the sewing machine with the upper thread and the lower thread prepared. Equipped with The thickness of the leather fabric is 2 to 12 millimeters; the upper thread and the lower thread are multifilament threads; The thickness of the upper thread is 1000 to 1800 decitex, The thickness of the lower thread is 1600 to 4000 decitex and is 600 decitex or more thicker than the upper thread; In the thread preparing step, the tension of the upper thread is adjusted to 15 to 21 Newtons, and the tension of the lower thread is adjusted to 1 to 2 Newtons.

2. A leather product in which machine stitching is performed on leather fabric, A first thread that constitutes the sewing machine stitch on a first surface of the front side of the leather fabric; a second thread constituting the sewing machine stitch on a second surface of the back side of the leather fabric; Equipped with The thickness of the leather fabric is 2 to 12 millimeters; the first yarn and the second yarn are multifilament yarns; The thickness of the first yarn is 1600 to 4000 decitex and is 600 decitex or more thicker than the second yarn; The thickness of the second yarn is 1000 to 1800 decitex; A leather product, wherein the knot of the first thread and the second thread is located closer to the second surface in the thickness direction of the leather fabric.

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