Artificial leather having water-based polyurethane foam layer and method of manufacturing the same

Abstract

The present invention relates to artificial leather having a water-based polyurethane foam layer including a fabric layer 110; a binder layer 111 laminated on the upper portion of the fabric layer 110; a water-based polyurethane foam layer 120 laminated on the upper portion of the fabric layer 110; a skin layer 130 laminated on the upper portion of the water-based polyurethane foam layer 120; and a surface treatment layer 140 laminated on the upper portion of the skin layer 130, wherein open cells are formed in the water-based polyurethane foam layer 120 through mechanical foaming. According to the present invention, a water-based polyurethane foam layer having open cells formed through mechanical foaming is applied to artificial leather for automobile seats.

Claims

1. An artificial leather comprising: a fabric layer; a binder layer laminated on an upper portion of the fabric layer; a water-based polyurethane foam layer laminated on an upper portion of the fabric layer; a skin layer laminated on an upper portion of the water-based polyurethane foam layer; and a surface treatment layer laminated on an upper portion of the skin layer, wherein the water-based polyurethane foam layer comprises open cells formed through mechanical foaming, wherein the binder layer comprises open cells formed through foaming, wherein the skin layer comprises open cells formed through foaming, and wherein the water-based polyurethane foam layer is formed to have a density of 200 to 850 g/L, a thickness of 50 to 600 μm, and a size of the open cells of 50 μm to 90 μm.

2. The artificial leather according to claim 1, wherein the fabric layer is formed using any one of fabric, knits, impregnated tricot, impregnated nonwoven fabric, dope dyed yarn, and nonwoven fabric.

3. The artificial leather according to claim 1, wherein the binder layer is formed using any one of a water-based polyurethane binder, an oil-based polyurethane binder, a solvent-free polyurethane binder, and a hot-melt adhesive.

4. The artificial leather according to claim 1, wherein the skin layer is formed of water-based polyurethane or oil-based polyurethane.

5. The artificial leather according to claim 1, wherein the surface treatment layer is formed through any one of water-based surface treatment, oil-based surface treatment, and oil-based/water-based complex surface treatment.

6. A method of manufacturing the artificial leather of claim 1, comprising: a first step of conveying release paper wound on a winding roll in one direction; a second step of applying a gel-phase resin mixture to a predetermined thickness to an upper portion of the conveyed release paper, and performing heat drying to form the skin layer; a third step of preparing a foam paste in which fine air layers are formed using a foam generator; a fourth step of applying the prepared foam paste to the upper portion of the skin layer, and performing curing and drying to form the water-based polyurethane foam layer having open cells; a fifth step of applying the binder layer to the upper portion of the water-based polyurethane foam layer; a sixth step of laminating fabric on the upper portion of the applied binder layer, and performing drying and curing to form the fabric layer; a seventh step of peeling off the release paper; and an eighth step of forming the surface treatment layer on the upper portion of the skin layer from which the release paper has been peeled off.

7. The method according to claim 6, wherein the heat drying process, the curing and drying process, and the drying and curing process for laminating the skin layer, the foam layer, and the fabric layer are performed in an oven at 80 to 140° C. for 2 to 5 minutes.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a side sectional view of the laminated structure of artificial leather having a water-based polyurethane foam layer according to the present invention.

(2) FIGS. 2(a) and 2(b) show the state of a water-based polyurethane foam layer according to the present invention before and after performing foaming, respectively.

(3) FIG. 3 is an image showing the results of measuring the thickness of each layer constituting artificial leather according to the present invention.

(4) FIG. 4 is a drawing showing a manufacturing process of artificial leather using an artificial leather manufacturing apparatus according to the present invention.

(5) FIG. 5 shows an enlarged image of the laminated structure of artificial leather having a water-based polyurethane foam layer according to the present invention.

(6) FIG. 6 shows test results for judging whether folded wrinkles are formed in artificial leather according to the present invention and conventional artificial leather.

(7) FIGS. 7 to 9 illustrate artificial leathers according to other embodiments of the present invention.

BEST MODE

(8) Hereinafter, the functions or constructions of preferred embodiments of the present invention will now be described more fully with reference to the accompanying drawings.

(9) Here, when reference numerals are applied to constituents illustrated in each drawing, it should be noted that like reference numerals indicate like elements throughout the specification.

(10) FIG. 1 is a side sectional view of the laminated structure of artificial leather having a water-based polyurethane foam layer according to the present invention, and FIGS. 2(a) and 2(b) show the state of a water-based polyurethane foam layer according to the present invention before and after performing foaming, respectively.

(11) Referring to FIG. 1, an artificial leather 100 having a water-based polyurethane foam layer according to a preferred embodiment of the present invention includes a fabric layer 110, a water-based polyurethane foam layer 120 laminated on the upper portion of the fabric layer 110, a skin layer 130 laminated on the upper portion of the water-based polyurethane foam layer 120, and a surface treatment layer 140 laminated on the upper portion of the skin layer 130 to prevent formation of surface scratches and improve abrasion resistance.

(12) The construction of the artificial leather according to the present invention will be described in detail as follows.

(13) First, any one of fabric, knits, impregnated tricot, impregnated nonwoven fabric, dope dyed yarn, and nonwoven fabric may be used as the fabric layer 110.

(14) In this case, since the water-based polyurethane foam layer 120 is laminated on the fabric layer 110 via a binder layer 111, the fabric layer 110 and the water-based polyurethane foam layer 120 may be firmly adhered to each other. Preferably, the binder layer 111 may be formed using any one of a water-based polyurethane binder, an oil-based polyurethane binder, a solvent-free polyurethane binder, and a hot-melt adhesive.

(15) In addition, open cells 121 are formed in the water-based polyurethane foam layer 120 through mechanical foaming.

(16) Specifically, in the manufacturing process of the artificial leather 100, water-based polyurethane used as a material in formation of the water-based polyurethane foam layer 120 is mixed and kneaded with high-pressure anhydrous air supplied through a foam generator.

(17) In addition, as shown in FIG. 2(a), a paste (water-based PU paste) in a state wherein a plurality of fine air layers (bubbles) is formed therein is applied to the upper portion of a corresponding layer. Then, when the paste is subjected to a predetermined drying and curing process in an oven, as shown in FIG. 2(b), the open cells 121 may be formed.

(18) Referring to FIG. 3, the size of the open cells 121 may be 20 to 200 μm, preferably 50 to 100 μm.

(19) In addition, the water-based polyurethane foam layer 120 is preferably formed to have a thickness of 50 to 600 μm. That is, when the water-based polyurethane foam layer 120 is formed to have a thickness of 50 μm or less, it is difficult to impart proper cushioning. On the other hand, when the water-based polyurethane foam layer 120 is formed to have a thickness of 600 μm or more, more cushioning than necessary may be imparted, and material cost may be increased.

(20) In addition, the water-based polyurethane foam layer 120 is preferably formed to have a density of 200 to 850 g/L. That is, when the density of the water-based polyurethane foam layer 120 is 200 g/L or less, more open cells 121 are formed than necessary. As a result, the stability of the foam layer 120 deteriorates. On the other hand, when the density of the water-based polyurethane foam layer 120 is 850 g/L or more, the amount of air to be supplied is small and thus, it is difficult to form as many open cells 121 as required. As a result, the stability of the foam layer 120 deteriorates.

(21) In addition, the skin layer 130 may be formed of water-based polyurethane or oil-based polyurethane.

(22) In addition, the surface treatment layer 140 may be formed through any one of water-based surface treatment, oil-based surface treatment, and oil-based/water-based complex surface treatment.

(23) Hereinafter, a method of manufacturing the artificial leather having a water-based polyurethane foam layer according to the present invention having the above-described structure will be described with reference to FIG. 4.

(24) FIG. 4 is a drawing showing a manufacturing process of artificial leather using an artificial leather manufacturing apparatus 200 according to the present invention.

(25) First, release paper 211 wound on a winding roll 210 is conveyed in one direction (S1). Here, the release paper 211 is provided so that an initial gel-phase resin mixture can be conveyed in a state of being applied to the release paper 211, and is peeled off after the manufacturing process of the artificial leather 100 is completed.

(26) A gel-phase resin mixture is applied to the upper portion of the conveyed release paper 211 to a predetermined thickness, and heat drying is performed to form the skin layer 130 (S2). In this case, the resin mixture is uniformly applied to the upper side of the release paper 211 to a predetermined thickness while passing through coating knives 221 provided directly above conveying rollers 220.

(27) A foam paste in which fine air layers are formed is prepared using a foam generator 230 (S3). In this case, the foam generator 230 mixes anhydrous air with a pressure of 6 to 8 bar and water-based polyurethane. Through this process, a paste (foam paste) containing water-based polyurethane in which plural air cells (bubbles) are formed may be prepared. At this time, the air cells in the paste are still not connected to each other (see FIG. 2(a)).

(28) The foam paste prepared in the foam generator 230 is applied to the upper portion of the skin layer 130, and then a predetermined drying and curing process is performed in an oven 240 to form the water-based polyurethane foam layer 120 having a thickness of 50 to 600 μm and including the open cells 121 (see FIG. 2(b)) (S4).

(29) Then, a binder layer 111 is applied to the upper portion of the water-based polyurethane foam layer 120 (S5).

(30) Fabric is laminated on the upper portion of the applied binder layer 111, and heat drying is performed to form the fabric layer 110 (S6).

(31) In this case, the heat drying process, the curing and drying process, and the drying and curing process for laminating the skin layer 130, the foam layer 120, and the fabric layer 110 constituting the artificial leather 100 are preferably performed in an oven at 80 to 140° C. for 2 to 5 minutes.

(32) In addition, the release paper 211 is peeled off, and the manufactured artificial leather 100 is wound on a separated winding roll 250 (S7).

(33) In the artificial leather 100 from which the release paper 211 is peeled off, the surface treatment layer 140 is formed on the upper portion of the skin layer 130 through another separate device.

(34) As shown in FIG. 5(b), the artificial leather 100 manufactured through the above-described process includes the water-based polyurethane foam layer 120 in which the open cells 121 are formed. Thus, the artificial leather 100 has excellent cushioning, moisture permeability, and heat dissipation ability, and may lower the surface temperature of automobile seats in summer. As a comparative example, in FIG. 5(a), a magnified image of conventional artificial leather not including the water-based polyurethane foam layer 120 according to the present invention is shown.

(35) The moisture permeability of the artificial leather 100 including the water-based polyurethane foam layer 120 manufactured by the manufacturing process of the present invention (Example shown in FIG. 1) and the moisture permeability of artificial leather and natural leather manufactured using other materials and by other methods were measured, and the results are shown in Table 1 below.

(36) TABLE-US-00001 TABLE 1 Moisture permeability Samples (g/m.sup.2 .Math. 24 h) Example of the present invention (foam 308 water-based PU) (Example of FIG. 1) Comparative Example 1 (water-based PU) 129 Comparative Example 2 (oil-based PU) 199 Comparative Example 3 (PVC) 10 Comparative Example 4 (natural leather) 557

(37) As shown in Table 1, it can be seen that the artificial leather 100 according to the present invention has a moisture permeability of 308 g/m.sup.2.Math.24 h. That is, the artificial leather 100 of the present invention has better moisture permeability than artificial leather not including the water-based polyurethane foam layer 120 according to Comparative Examples 1 to 3. In addition, the measured value of the artificial leather 100 is close to that of natural leather of Comparative Example 4.

(38) In addition, when the artificial leather 100 in which the water-based polyurethane foam layer 120 having a predetermined thickness and including the open cells 121 according to the present invention is formed is applied to automobile seats, the artificial leather 100 may prevent formation of folded wrinkles.

(39) That is, when conventional artificial leather not including a foam layer or conventional artificial leather including closed cells formed through chemical foaming is used to cover automobile seats, folded wrinkles may be formed in rounded portions. The wrinkled portions may be damaged due to frequent contact with vehicle occupants.

(40) Hereinafter, whether folded wrinkles are formed when the artificial leather 100 according to the present invention is applied to automobile seats will be described. FIGS. 6(a) and 6(b) show the results of testing whether folded wrinkles are formed in the artificial leather according to the present invention and conventional artificial leather.

(41) First, conventional non-foam artificial leather fabric and the foam fabric of the present invention (the artificial leather 100) were prepared. Then, each fabric was pressed with the thumb while holding the fabric by hand.

(42) As a result, as shown in FIG. 6(a), it can be seen that folded wrinkles are formed on the surface of the conventional non-foam fabric.

(43) On the other hand, as shown in FIG. 6(b), it can be seen that folded wrinkles are hardly formed on the surface of the foam fabric according to the present invention.

(44) The artificial leather 100 according to the present invention includes the water-based polyurethane foam layer 120 including the open cells 121 formed by mechanical foaming instead of conventional chemical foaming. Thus, the artificial leather 100 has excellent cushioning, moisture permeability, and heat dissipation ability, and may lower the surface temperature of automobile seats in summer.

(45) In particular, in the case of water-based polyurethane, which is a main ingredient of the water-based polyurethane foam layer 120, dimethylformamide, an organic solvent, is not used, thereby improving environmental friendliness.

(46) In addition, when the artificial leather 100 in which the water-based polyurethane foam layer 120 having a predetermined thickness and including the open cells 121 is formed is applied to automobile seats, formation of folded wrinkles may be prevented.

(47) The preferred embodiments of the present invention have been described with reference to the accompanying drawings. However, the scope of the present invention is not limited by these embodiments. In addition, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention.

(48) In this case, in the present invention, the case wherein the open cells 121 are formed in the water-based polyurethane foam layer 120 has been described as an example. However, the present invention is not limited thereto.

(49) For example, as shown in FIGS. 7 to 9, in addition to the water-based polyurethane foam layer 120, open cells 111a and 131 may be formed in any one of the binder layer 111 and the skin layer 130, or in both the binder layer 111 and the skin layer 130 through foaming. Accordingly, the moisture permeability of the artificial leather 100 may be efficiently improved.

(50) In particular, when the open cells 121 and 131 are formed in both the foam layer 120 and the skin layer 130 constituting the artificial leather 100 of the present invention shown in FIG. 7, as shown in Table 2, it can be seen that the artificial leather 100 has a moisture permeability of 607 g/m.sup.2.Math.24 h.

(51) TABLE-US-00002 TABLE 2 Moisture permeability Samples (g/m.sup.2 .Math. 24 h) Example of the present invention 308 (Example of FIG. 1) Example of the present invention 607 (Example of FIG. 7) Comparative Example 1 (water-based PU) 129 Comparative Example 2 (oil-based PU) 199 Comparative Example 3 (PVC) 10 Comparative Example 4 (natural leather) 557

(52) That is, as shown in Table 2, considering that the moisture permeability of Comparative Example 4 (natural leather) is 557 g/m.sup.2.Math.24 h, it can be seen that the artificial leather 100 of the present invention (Example of FIG. 7) has better moisture permeability than natural leather.

DESCRIPTION OF SYMBOLS

(53) 100: ARTIFICIAL LEATHER 110: FABRIC LAYER 111: BINDER LAYER 120: WATER-BASED POLYURETHANE FOAM LAYER 111a, 121, 131: OPEN CELLS 130: SKIN LAYER 140: SURFACE TREATMENT LAYER 200: ARTIFICIAL LEATHER MANUFACTURING APPARATUS 210, 250: WINDING ROLL 211: RELEASE PAPER 220: CONVEYING ROLLERS 221: COATING KNIVES 230: FOAM GENERATOR 240: OVEN