Lightweight and flexible web-structured recycled leather sheet and a manufacturing method thereof

Abstract

The present invention can be manufactured a recycled leather sheet treated with waterproof and flame retardant in a form of a sheet having a thickness of 10 to 500 mm, and maintains a weight of 700 to 1200 g/m.sup.2 of a final recycled leather weight. In addition, natural fibers, synthetic fibers, and recycled yarns can be plantation treatment on recycled leather by needle punching process to realize the lightweight and flexibility of recycled leather sheet.

Claims

1. A method of manufacturing a lightweight and flexible web-structured recycled leather sheet, comprising: using at least any one of natural yarn fibers, synthetic fibers, and recycled yarns, or combination thereof, mixing for manufacturing into a fiber sheet in a form of a non-woven fabric; performing plantation treatment by a needle punching process after putting the non-woven fabric sheet on the recycled leather; and impregnating the plantation treated recycled leather with a rubber-based adhesive, thereby manufacturing the recycled leather sheet of web structure having the lightness and flexibility.

2. The method of manufacturing the lightweight and flexible web-structured recycled leather sheet of claim 1, further comprising: drying the impregnated recycled leather and uniformly treating the surface of the recycled leather by a pressing roll process.

3. The method of manufacturing the lightweight and flexible web-structured recycled leather sheet of claim 2, further comprising impregnating the surface-treated recycled leather with an eco-friendly adhesive material.

4. The method of manufacturing the lightweight and flexible web-structured recycled leather sheet of claim 1, further comprising: improving a flexibility, a soft texture, and a physical strength of the recycled leather impregnated in the rubber-based adhesive or the recycled leather impregnated in the eco-friendly adhesive through a needle punching process.

5. The method of manufacturing a web-structured recycled leather sheet with lightness and flexibility of claim 1, wherein the non-woven fiber sheet is composed of two or three layers.

6. The method of manufacturing a lightweight and flexible web-structured recycled leather sheet of claim 5, further comprising combining synthetic fibers or painting the surface of the recycled leather after the needle punching process.

7. The method of manufacturing the lightweight and flexible web-structured recycled leather sheet of claim 1, wherein the non-woven fiber sheet comprises: preparing 0.1500 mm long and short fiber using at least any one of natural yarn fiber, synthetic fiber, and recycled yarn, and then mixing at least any one of the long and short fiber, and then a process of manufacturing it into a non-woven fiber sheet.

8. The manufacturing method of the recycled leather sheet of the web structure having the lightens and flexibility the synthetic fiber of claim 1: when using a mixture of natural fiber, synthetic fiber, and recycled yarn, the mixing ratio is natural fiber:synthetic fiber:recycled yarn of 7:3:1, 6:2:2, or 5:3:2.

9. The method of manufacturing a lightweight and flexible web-structured recycled leather sheet of claim 1, wherein a thickness of the fiber sheet is 10 to 500 mm.

10. The recycled leather sheet of the web structure having the lightness and flexibility manufactured with the method of claim 1.

11. A lightweight and flexible web-structured recycled leather sheet, comprising: a recycled leather layer 10; a nonwoven fabric sheet layer 20 transplanted by a needle punching process formed on both surfaces based on the recycled leather layer 10; rubber-based adhesive layers 30 are formed on both surfaces of the nonwoven fabric sheet layer 20 by an impregnation process; and a polyurethane layer 40 formed on both surfaces of the rubber adhesive 30 by an impregnation process.

12. The lightweight and flexible web-structured recycled leather sheet, of claim 11, further comprising: a synthetic fiber layer 50 and a coating layer 60 formed on the upper surface of the polyurethane layer 40.

Description

BRIEF EXPLANATION OF DRAWINGS

[0039] FIG. 1 is a flowchart sequentially showing a method of manufacturing a recycled leather sheet having a web structure having light weight and flexibility according to a preferred embodiment of the present invention.

[0040] FIG. 2 is a cross-sectional view showing the configuration of a recycled leather sheet having a web structure having light weight and flexibility manufactured by the method shown in FIG. 1.

DETAILED EMBODIMENT

[0041] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings as follows: In the detailed description to be described later, a representative embodiment of the present invention will be presented to achieve the above-described technical problem. In addition, other embodiments that may be presented with the present invention are replaced with descriptions in the configuration of the present invention.

[0042] The term web structure used in the present invention refers to a three-dimensional network structure, a structure in which fiber structures are intricately intertwined like a spider web.

[0043] Specifically, selecting any one or natural fibers, synthetic fibers, and recycled fibers are selectively mixed on the surface of the recycled leather, and the mixed natural fibers, synthetic fibers, and recycled fibers are manufactured into a nonwoven fiber sheet having two or three layers through a carding process.

[0044] This means a three-dimensional network structure in which the fibers penetrate into the recycled leather and are intricately intertwined with each other by treating the recycled leather with plantation treatment through a needle punching process.

[0045] In addition, the term sheet or layer used in the present invention means a form, which may include a sheet, a film, and/or plate form(s), unless the form is specifically mentioned.

[0046] Aspect(s) of the present invention is to realize a method of manufacturing a web-structured recycled leather sheet having a three-dimensional network structure by treating the recycled leather with plantation treatment through a needle punching process while using natural fiber, synthetic fiber, recycled yarn, etc. alone or selectively mixing the same and using the same as a fiber material.

[0047] At this time, the fibers are made of a sheet layer such as a nonwoven fabric through a carding process, preferably made of a nonwoven sheet in a form of a double or triple layer.

[0048] According to aspect(s) of the present invention, a recycled leather sheet manufactured by the above method realizes light weight and flexibility, has a resource recycling effect, and is a low-carbon eco-friendly product. The recycled leather sheet can be used in various industrial fields such as shoes, bags, wallets, and car seats. However, it is not limited thereto.

[0049] According to aspect(s) of the present invention, in manufacturing a web structure type recycled leather sheet, a recycled leather made by the manufacturing method disclosed in U.S. Pat. No. 10,207,476, titled REINFORCED LEATHER and U.S. Pat. No. 10,941,255, titled METHOD FOR MANUFACTURING LIGHTWEIGHT FOAMED RECYCLED LEATHER AND RECYCLED LEATHER PRODUCED BY THE METHOD THEREOF may be used. However, it is not limited thereto.

[0050] In other words, the method for manufacturing recycled leather disclosed in the above-mentioned U.S. patent is to remove shaving scraps, which are inevitably generated to control the thickness during a leather manufacturing process, and various paint-coated leather cuts generated from shoes, bags, car seats, etc. Waste (finished leather trimming scraps) is mixed at a ratio of 7:3 to 5:5 and shredded, then performing a usual wet method and drying process, and then foamed using a squeezing roller at a temperature of 60120 C. And the waste is used to manufacture a recycled leather with a uniform thickness through a normal buffing process.

[0051] According to aspect(s) of the present invention, a recycled leather sheet having a web structure having light weight and flexibility can be manufactured by using the recycled leather mentioned above, or the recycled leather sheet of the present invention can be manufactured by using a general recycled leather manufactured by a conventional method. Of course, the recycled leather sheet of the present invention, which is made only by using general recycled leather, also has light weight and flexibility.

[0052] In the present invention, fibers are placed on the surface of a recycled leather, a nonwoven fabric sheet having a double or a triple layer is placed on the recycled leather by a carding process, and then a fiber (a nonwoven fabric sheet, hereinafter referred to as a nonwoven fabric sheet) is planted on the recycled leather by a needle punching process.

[0053] At this time, as the fibers used in the present invention, natural fibers, various synthetic fibers, recycled yarns, and the like can be used alone or at least one of them can be selected and mixed. The natural fibers include cotton, silk, fur, and the like, and synthetic fibers include polyethylene fibers and polyurethane fibers.

[0054] The natural fibers may include cotton, silk, fur, and the like, and synthetic fibers may include polyethylene fibers and polyurethane fibers. The recycled yarn may include polyethylene terephthalate (PET), poly lactic acid (PLA), and bio-fiber, and the like.

[0055] According to the aspect(s) of the present invention, a dipping process is performed to impregnate a recycled leather after plantation treatment by a needle punching process into a rubber-based adhesive such as latex, and then drying the same and pressing the surface of the recycled leather with a squeezing roller is performed.

[0056] This is to smooth the fibers exposed to the surfaces (front and back) of the recycled leather, wherein the fibers may be natural fibers, synthetic fibers, recycled yarns, or a mixture thereof.

[0057] According to aspect(s) of the present invention, the recycled leather having a smooth surface is passed through a needle punching machine (M/C) once or twice to realize flexibility, improve physical strength, and produce a recycled leather sheet having a web structure.

[0058] According to aspect(s) of the present invention, various materials can be coated on the surface of the recycled leather sheet. For example, the recycled leather sheet can be coated by a water-based coating method having a flame-retardant function or an environmentally-friendly non-polluting functional polyurethane hotmelt thin film bonding method.

[0059] Hereinafter, a method of manufacturing a recycled leather sheet having a web structure having light weight and flexibility of the present invention will be described in detail with reference to the drawings.

[0060] As shown in FIG. 1, a method for manufacturing a recycled leather sheet according to the present invention may include: [0061] Step 1) natural fibers such as cotton, silk, and fur, and various synthetic fibers such as polyethylene fibers or polyurethane fibers, fibers and recycled yarns including PET, are made into long and short fibers with a length of 0.1 to 500 mm, then these are used individually or at least one of them is selected and mixed, and then processed through the usual carding process or pressed with a squeezing roller to form sheets with a thickness of 10 to 500 mm, That is, the step of manufacturing a non-woven fiber sheet; [0062] Step 2) placing the fiber sheet of the step 1 on top of the recycled leather and then passing it through a needle punching machine (M/C) for a plantation treatment; [0063] Step 3) impregnating the recycled leather of the step 2 with a rubber-based adhesive such as latex to smooth the surface of the recycled leather, i.e., a dipping treatment; [0064] Step 4) after drying the recycled leather after dipping treatment in the step 3, passing it through a pressing roll to evenly treat the surface of the recycled leather; [0065] Step 5) impregnating the recycled leather that has gone through the step 4 with eco-friendly binding materials including polyurethane to have waterproof and flame-retardant functions; [0066] Step 6) passing the recycled leather of the step 5 through the needle punching M/C once or three or more times to ensure that the recycled leather has flexibility and a soft texture; and [0067] Step 7) manufacturing a recycled leather sheet of the present invention by combining synthetic fibers with the recycled leather that has passed step 6 above.

[0068] The manufacturing method of the present invention can be manufactured in a form of a sheet having a thickness of 0.1 to 50 mm, maintains a weight of 700 to 1200 g/m.sup.2 of final recycled leather, and can be manufactured as a recycled leather sheet treated with water proof and flame retardant.

[0069] In addition, an aspect of the present invention can realize light weight and flexibility of the recycled leather sheet by planting treatment of natural fibers, synthetic fibers, recycled yarns, and the like in the recycled leather through a needle punching process. For example, according to aspect(s) of the present invention, preferably a recycled leather may have 700-1,100 g/m.sup.2 of lightweight and/or may have greater than 2.5 mm of softness.

[0070] According to the present invention, the recycled leather sheet manufactured by the manufacturing method may include: a low carbon eco-friendly product can be manufactured by recycling a shaving scrap generated during a leather manufacturing process and finished leather trimming scraps generated in shoes, bags, car seats, etc. as well as being usable for a seat sheet for transportation (for example, a vehicle, a ship, an aircraft, etc.) including materials for shoes, bags, and sofas. In addition, a recycling effect of resources can be realized.

[0071] Hereinafter, a method of manufacturing a recycled leather sheet having a web structure having light weight and flexibility according to the present invention will be described in detail, and the present invention will be described through preferred embodiments that can be easily performed by a person with ordinary skills in the art to which the present invention belongs.

Embodiments

[0072] FIG. 1 is a diagram sequentially showing a method of manufacturing a recycled leather sheet having a web structure having light weight and flexibility according to a preferred embodiment of the present invention. FIG. 2 is a diagram showing the configuration of a recycled leather sheet having a web structure having light weight and flexibility manufactured by the method shown in FIG. 1.

[0073] Referring to FIGS. 1 and 2, a method for manufacturing a recycled leather sheet having a web structure having light weight and flexibility according to the present invention include: the steps of: using a recycled leather made by a manufacturing method of the present invention or a recycled leather manufactured by a conventional method as a main material; and a method of manufacturing the recycled leather sheet by planting a nonwoven fabric sheet made of natural fibers, various synthetic fibers, recycled yarns, etc. on the surface of the recycled leather through a needle punching process. That is to manufacture a recycled leather by performing a plantation treatment by a needle punching. The method may include the following 7 steps. [0074] Step 1: This is the step where natural fibers, synthetic fibers, recycled yarns, etc. are used alone or one or more of them is selected and mixed, and then manufactured into a fiber sheet with a thickness of 10 to 500 mm.

[0075] Natural fibers used in the present invention may include cotton, silk, or fur, and synthetic fibers may include polyethylene fibers or polyurethane fibers. A recycled fiber may refer to a general recycled fiber and may be PET as an example.

[0076] According to the present invention, the natural fibers and various synthetic fibers and recycled fibers can be made of long and short fibers having a length of 0.1 to 500 mm, and then used as each fiber alone, or one or more of the fibers can be selected and mixed.

[0077] A selected fiber or a mixed fiber is pressed by a conventional carding process and a squeezing roller to produce a nonwoven fiber sheet having a thickness of 10 to 500 mm. In this case, a nonwoven fabric sheet in two or three layers may be formed according to aspect(s) of the present invention. However, it is not limited thereto.

[0078] According to an aspect of the present invention, the natural fibers, synthetic fibers, and recycled yarns described above are used alone or in combination, wherein the mixing ratio can be uniformly mixed in a ratio of natural fibers, synthetic fibers, and recycled yarns in a ratio of 7:3:1, 6:2:2, or 5:3:2.

[0079] In this way, individual or mixed fibers are passed through a conventional carding roller equipped with a needle, and then pressed with a conventional squeezing roller to form a fiber sheet. At this time, it is desirable to mold the fiber sheet thinly to a thickness. [0080] Step 2: a step of placing the fiber sheet passed through the step 1 on recycled leather and performing a plantation treatment through a needle punching process.

[0081] In this case, various needles can be used in the needle punching process, and preferably, an arrowhead or a needle having a barb shape of a fishing needle can be used.

[0082] The recycled leather used in the present invention may include shaving scraps generated during a general leather manufacturing process, and recycled leather mixed and crushed in a ratio of 7:3 to 5:5 (including painted leather cutting waste) generated during a manufacturing process of shoes, bags, car seats, and the like, and made by a conventional wet method.

[0083] In addition, the present invention is capable of mixing and crushing the washing pieces and various leather cutting wastes, and then using recycled leather made by a general dry method.

[0084] According to aspects of the present invention, a recycled leather made by the manufacturing method disclosed in U.S. Pat. No. 10,207,476, titled Reinforced Leather and U.S. Pat. No. 10,941,255, titled Method for Manufacturing Lightweighted Foamed Recycled Leather and Recycled Leather Ceramic Products by the Method Thereof may be used.

[0085] According to aspects of the present invention, a recycled leather made by the above method and a nonwoven fiber sheet made of a double layer or a triple layer made by the step 1 are treated with a plantation treatment by a needle punching process. More specifically, the recycled leather having a web structure of a two-layer structure is manufactured by placing the fiber sheet passed through the step 1 on the recycled leather and transplanting the fiber sheets while slowly passing the fiber sheets through a needle punching machine (M/C).

[0086] At this time, the plantation treatment condition (plantation working condition) of the needle punching machine is shown in Table 1 below.

TABLE-US-00001 TABLE 1 Plantation treatment method Plantation treatment condition Treatment speed 2.5~10.0 m/min Machine speed per minute(RPM) 800~1,200 RPM Needle cap 2~8 mm Needle depth 5.5~10.5 mm Number of needles 10,000~20,000 Needle standard size #40, FWD-D3063 40RB, 2 2 2 Neeld shape Barb shape

[0087] According to aspect(s) of the present invention, a nonwoven fabric sheet is planted on the recycled leather by a needle punching process, i.e., a plantation treatment is performed. A purpose according to aspects of the present invention is to supplement tearing strength characteristics of the recycled leather sheet, to provide natural texture and softness, and to provide a quality similar to that of the natural leather sheet. [0088] Step 3: This is a step in which the surface of the recycled leather is smoothened by dipping treatment of the recycled leather with a rubber-based adhesive or a water-soluble PU-based adhesive.

[0089] Fibers exposed on the front and back of the recycled leather, specifically, during the process of the non-woven fiber sheet that has passed step 1 being treated with the recycled leather through the needle punching process in step 2, the fibers may be protruded from the front and back of the recycled leather.

[0090] In order to smooth the fibers exposed on the surface (front and back) of the recycled leather, a dipping process is performed to impregnate the recycled leather with a rubber-based adhesive such as latex, i.e., dipping process is performed. [0091] Step 4: After drying the recycled leather that has gone through step 3 above, the surface of the recycled leather is treated uniformly through a squeezing roller process.

[0092] In other words, this is a step to improve the homogeneity of the surface of the recycled leather. [0093] Step 5: a step of dipping process of the recycled leather that has gone through step 4 into eco-friendly binding materials including polyurethane.

[0094] Aspects of the present invention can use a water-soluble PU-based adhesive material as an eco-friendly adhesive material. According to aspects of the present invention, the recycled leather that has gone through step 4 described above can be impregnated with an eco-friendly adhesive material, and can also be impregnated with a waterproofing agent and a flame retardant to provide waterproofing and flame retardant functions. [0095] Step 6: This is the step of improving the flexibility, soft texture, and physical strength of the recycled leather that has gone through step 5 above through a needle punching process. At this time, it is preferable to perform the needle punching process once or twice, and it can be performed more times depending on the quality control situation of the product.

[0096] If the manufacturing process of step 6 is performed, the recycled leather sheet of the present invention not only provides a soft texture, but also provides physical strength (strengthening the fiber structure), strengthens adhesion, and improves peel strength. In particular, it is possible to manufacture recycled leather sheets with quality characteristics similar to natural leather.

[0097] The recycled leather sheet is thinly formed to a thickness of 10 to 500 mm through a needle punching process, and is manufactured as a recycled leather sheet with a three-layer web structure.

[0098] According to aspects of the present invention, the needle punching process of step 6 can be performed on the recycled leather that has undergone step 3, specifically, the recycled leather impregnated with a rubber-based adhesive. At this time, it is desirable to perform the needle punching process once or twice, and may be performed more times depending on the quality control situation of the product.

[0099] Fibers exposed to the front surface and the rear surface of the recycled leather, specifically, the nonwoven fiber sheet which has passed through the step 1 protrude to the front surface and the rear surface of the recycled leather during a process of transplanting the nonwoven fiber sheet to the recycled leather by the needle punching step of the step 2. [0100] Step 7: a step of manufacturing a recycled leather sheet of the present invention through a cloth combining process and a coating process of synthetic fibers of the recycled leather of the step 6;

[0101] In this case, the painting process is to implement various surface treatment effects of the recycled leather sheet. The painting process is a process of painting and finishing in various ways such as a spray method, a padding method, a roll coating method, and a digital printing method.

[0102] As shown in FIG. 2, a recycled leather sheet made by the manufacturing method of the present invention is preferably made through the manufacturing process of step 1 to step 7, which includes: a nonwoven fabric sheet layer 20 transplanted by a needle punching process is formed on both surfaces of the recycled leather layer 10; rubber-based adhesive layer 30 is formed on both surfaces of the nonwoven fiber sheet layer 20 by an impregnation process, i.e., a dipping process; and polyurethane layer 40 is formed on both surfaces of the rubber adhesive 30 by an impregnation process. In addition, if necessary, a synthetic fiber layer 50 and a coating layer 60 made through the above-described step 7 may be formed on the upper surface of the polyurethane layer 40.

[0103] The recycled leather sheet of the present invention, which is composed of various sheet layers, can realize light weight of 700-1200 g/m.sup.2 compared to the weight of the final recycled leather, and can realize fullness, tightness, and softness. In addition, waterproof and flame-retardant functions can be realized through the manufacturing process of step 5.

[0104] According to aspect(s) of the present invention, the recycled leather sheet can be used as a low carbon eco-friendly resource recycling composite material which can be used for a seat sheet (for example, a vehicle, a ship, an aircraft, etc.) for transportation, including materials for shoes, bags, and sofas.

TABLE-US-00002 [explanation of symbols] 10: Recycled leather layer 20: Non-woven fiber sheet layer 30: Rubber-based adhesive layer 40: Polyurethane layer 50: Synthetic fiber layer 60: coating layer