Patent Abstract:
Disclosed is a method for making artificial leather with superficial texture. In the method, a substrate is coated, in a non-overall manner, with a wet polyurethane resin. After curing, there is provided a polyurethane resin coated on releasing paper. Thus, a semi-product is made. Texture of the releasing paper is transferred to a surface of the semi-product. Then, the semi-product with the texture on the surface is coated with a layer of a chemical. A machine is used to heat and flatten the surface of the semi-product. Finally, the semi-product is physically finished by forces so that the surface of the final product is formed with texture like that of real leather.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application is a continuation-in-part application of U.S. patent application Ser. No. 11/270,436 filed Nov. 9, 2005, which is a continuation-in-part application of U.S. patent application Ser. No. 11/199,437 filed Aug. 8, 2005. 
     
    
     BACKGROUND OF INVENTION  
       [0002]     1. Field of Invention The present invention relates to a method for making artificial leather with superficial texture and, more particularly, to artificial leather made by a special attaching manner and a surface-processing method so that the artificial leather is made with texture and provides soft, comfortable touch like real leather.  
         [0003]     2. Related Prior Art  
         [0004]     A conventional method for making artificial leather includes two processes, a dry process and a wet process. The dry process includes two steps. Firstly, releasing paper is coated with a layer of a dry polyurethane resin with thickness of 0.01 to 0.10 mm. Secondly, the dry polyurethane resin layer is coated with an adhesive polyurethane resin (“paste”) for forming an adhesive layer with thickness of 0.01 to 0.08 mm. The wet process includes four steps. Firstly, a substrate is submerged in a polyurethane resin so that a submersion layer is formed in the substrate. Secondly, the substrate is coated with a coating polyurethane resin. Thirdly, the substrate and the layers are cured, washed and subject to other wet processing for forming a foam layer on the substrate. Fourthly, the adhesive layer the laminate resulting from the dry process is attached to the foam layer of the laminate resulting from the wet process. The releasing paper is removed to provide artificial that looks and feels like real leather.  
         [0005]     In the adhesion, the adhesive layer is formed by providing the paste in an overall manner. This coating however makes the artificial leather hard and feel like plastic instead of real leather. Moreover, since the releasing paper is formed with texture by continuous printing, the texture of the artificial leather reprinted from the texture of the releasing paper is not irregular and vivid as with real leather. Hence, artificial leather is not accepted by the public.  
         [0006]     The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.  
       SUMMARY OF INVENTION  
       [0007]     It is the primary objective of the present invention to provide a method for making artificial leather that is soft and flexible and includes vivid texture.  
         [0008]     To achieve the primary objective, the method includes the step of coating a substrate with a porous wet polyurethane resin film by providing paste in a non-overall manner. After curing, a polyurethane resin coated on releasing paper is attached to the wet polyurethane resin film, and texture of the releasing paper is imprinted thereon. Then, surface-processing is done by coating a layer of chemical on a semi-product with texture. A machine is used to iron the semi-product. Forces are used to provide a final product of the artificial leather that is soft and flexible and includes vivid texture.  
         [0009]     In the step of providing the paste, the non-overall manner is a gap, disconnected, an irregular manner, a regular manner, a gravure, an letterpress or a spotted manner. The area of the coating of the paste is 10% to 90% of the total area. The coating is hollow. After subject to the forces, the fibers of the substrate become fluffy and the final product is elastic and soft like real leather.  
         [0010]     The chemical may be a polyurethane resin, a polyester resin, a PU resin, a silicon-containing chemical and a wax-containing chemical. The ironing is conducted at a temperature of 20 to 300 degrees Celsius.  
         [0011]     The forces may be exerted by throwing the semi-product onto an external object, throwing an external object onto the semi-product or throwing the semi-product onto another semi-product. The forces may be exerted by a solid object, a pressurized air jet or a pressurized water jet and scrubbing. Alternatively, the forces may be exerted by vibration in all directions, pressurized high-speed pumping and throwing or free falling. Moreover, air or liquid can be used to exert the forces to make the fibers of the substrate fluffy so that the final product is elastic and soft like real leather and that the texture of the final product made by the releasing paper is irregular and vivid.  
         [0012]     Other objectives, advantages and features of the present invention will become apparent from the following description referring to the attached drawings.  
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0013]     The present invention will be described through detailed illustration of three embodiments referring to the drawings.  
         [0014]      FIG. 1  is a cross-sectional view of artificial leather including a substrate according to the present invention.  
         [0015]      FIG. 2  is a cross-sectional view of the artificial leather shown in  FIG. 1  wherein the substrate is made of ultra-fine fibers.  
         [0016]      FIG. 3  is a cross-sectional view of the artificial leather shown in  FIG. 1  wherein the substrate is a woven or non-woven fabric.  
         [0017]      FIG. 4  is a cross-sectional view of the artificial leather shown in  FIG. 1  wherein the substrate includes an ultra-fine fiber layer and a woven or non-woven fabric. 
     
    
     DETAILED DESCRIPTION OF EMBODIMENTS  
       [0018]     Referring to  FIG. 1 , there is shown artificial leather  200  according to the present invention. The artificial leather  200  includes a substrate  201  and a composite layer  203  coated on the substrate  201 . The substrate  201  may be a woven fabric, a non-woven fabric, an ultra-fine fiber layer or any combination thereof. The composite layer  203  includes a wet polyurethane resin film  204  and a polyurethane resin layer  205 . The wet polyurethane resin film  204  includes a porous structure. The polyurethane resin layer  205  is coated on releasing paper and attached to the polyurethane resin film  204  and subject to surface-processing. The polyurethane resin layer  205  includes texture  206  reprinted from the releasing paper.  
         [0019]     To make the artificial leather  200 , the substrate  201  is coated with paste in a non-overall manner to form an adhesive layer  202  for attaching the wet polyurethane film  204  to the substrate  201 . A polyurethane resin is coated on the releasing paper. The releasing paper is formed with texture and attached to the wet polyurethane film  204  with the porous structure. After removing the releasing paper, there is provided a semi-product of the artificial leather  200  with the texture  206  on the surface. The texture  206  of the semi-product of the artificial leather  200  is coated with a chemical at a quantity of 10 to 200 g/m 2  printing or spraying, dried and ironed at a temperature of 20 to 200 degrees Celsius by a wheel. A drawback of a dry surface is overcome so that the artificial leather  200  provides comfortable touch and a shinning look like real leather. Then, irregular forces are exerted on the texture  206  of the semi-product of the artificial leather  200  for twisting the texture  206  so that the texture  206  is irregular and vivid like that of real leather.  
         [0020]     Referring to  FIG. 2 , the substrate is an ultra-fine fiber layer  300  with thickness of 0.2 to 4.0 mm. There is provided an adhesive layer  301  in a dotted non-overall manner at a quantity of 10 to 300 g/m 2  for attaching a wet polyurethane resin film  302  with a porous structure and thickness of 0.1 to 1.0 mm. After curing, an ultra-fine fiber semi-product is made. On the other hand, releasing paper is coated with a polyurethane resin at a quantity of 10 to 500 g/m 2 . The polyurethane resin layer is attached to the ultra-fine fiber semi-product. After removing the releasing paper, a semi-product of the artificial leather is provided with texture. The texture of the semi-product of the artificial leather is coated with a chemical at a quantity of 10 to 200 g/m 2  by printing or spraying, dried and ironed at a temperature of 20 to 300 degrees Celsius by a wheel. A drawback of a dry surface is overcome so that the artificial leather provides comfortable touch and a shinning look like real leather. Then, the semi-product of the artificial leather is thrown and scrubbed for example to provide irregular and vivid texture  303  like that of real leather.  
         [0021]     Referring to  FIG. 3 , there is provided a substrate  400  that is a woven fabric with thickness of 0.1 to 2.0 mm or a non-woven fabric with thickness of 0.2 to 4.0 mm. There is provided an adhesive layer  401  in a dotted non-overall manner at a quantity of 10 to 300 g/m 2  for attaching a wet polyurethane resin film  402  with a porous structure and thickness of 0.1 to 1.0 mm. After curing, a woven or non-woven fabric semi-product is made. On the other hand, releasing paper is coated with a polyurethane resin at a quantity of 10 to 500 g/m 2 . The polyurethane resin layer is attached to the ultra-fine fiber semi-product. After removing the releasing paper, a semi-product of the artificial leather is provided with texture. The texture of the semi-product of the artificial leather is coated with a chemical at a quantity of 10 to 200 g/m 2  by printing or spraying, dried and ironed at a temperature of 20 to 300 degrees Celsius by a wheel. A drawback of a dry surface is overcome so that the artificial leather provides comfortable touch and a shinning look like real leather. Then, the semi-product of the artificial leather is thrown and scrubbed for example to provide irregular and vivid texture  403  like that of real leather.  
         [0022]     Referring to  FIG. 4 , there is provided a substrate  500  that is a woven fabric with thickness of 0.1 to 2.0 mm or a non-woven fabric with thickness of 0.2 to 4.0 mm. There is provided a first adhesive layer  501  in a dotted non-overall manner at a quantity of 10 to 300 g/m 2  for attaching a wet polyurethane resin film  502  with a porous structure and thickness of 0.1 to 1.0 mm. After curing, a woven or non-woven fabric semi-product is made. On the other hand, there is provided a second adhesive layer  503  in a dotted non-overall manner for attaching an ultra-fine fiber layer  504  for providing an ultra-fine fiber semi-product. Releasing paper is coated with a polyurethane resin at a quantity of 10 to 500 g/m 2 . The polyurethane resin layer is attached to the ultra-fine fiber semi-product. After removing the releasing paper, a semi-product of the artificial leather is provided with texture. The texture of the semi-product of the artificial leather is coated with a chemical at a quantity of 10 to 200 g/m 2  by printing or spraying, dried and ironed at a temperature of 20 to 300 degrees Celsius by a wheel. A drawback of a dry surface is overcome so that the artificial leather provides comfortable touch and a shinning look like real leather. Then, the semi-product of the artificial leather is thrown and scrubbed for example to provide irregular and vivid texture  505  like that of real leather.  
         [0000]     Sample 1  
         [0023]     An ultra-fine fiber sheet that is 1.1 mm thick is coated with a porous polyurethane film that is 0.4 mm thick at a quantity of 10 to 500 g/m 2  in a dotted non-overall manner. Releasing paper is coated with a dry polyurethane resin at a quantity of 300 g/m 2 , and dried and attached so that texture of the releasing paper is reprinted onto the ultra-fine fiber semi-product. Surface-processing is done by providing a polyurethane chemical at a quantity of 50 g/m 2 . Ironing is done by a wheel at a temperature of 90 degrees Celsius. Thus, the artificial leather provides a look and touch like real leather. The artificial leather is thrown and scrubbed so that texture of the artificial leather is twisted and becomes irregular and vivid like that of real leather.  
         [0000]     Sample 2  
         [0024]     A woven fabric that is 0.7 mm thick is coated with a porous polyurethane film that is 0.4 mm thick at a quantity of 10 to 500 g/m 2  in a dotted non-overall manner. Releasing paper is coated with a dry polyurethane resin at a quantity of 300 g/m 2 , and dried and attached so that texture of the releasing paper is reprinted onto the ultra-fine fiber semi-product. Surface-processing is done by providing a polyurethane chemical at a quantity of 50 g/m 2 . Ironing is done by a wheel at a temperature of 90 degrees Celsius. Thus, the artificial leather provides a look and touch like real leather. The artificial leather is thrown and scrubbed so that texture of the artificial leather is twisted and becomes irregular and vivid like that of real leather.  
         [0000]     Sample 3  
         [0025]     A non-woven fabric that is 0.9 mm thick is coated with a porous polyurethane film that is 0.4 mm thick at a quantity of 80 g/m 2  in a spotted non-overall manner. Releasing paper is coated with a dry polyurethane resin at a quantity of 300 g/m 2 , and dried and attached so that texture of the releasing paper is reprinted onto the ultra-fine fiber semi-product. Surface-processing is done by providing a polyurethane chemical at a quantity of 60 g/m 2 . Ironing is done by a wheel at a temperature of 90 degrees Celsius. Thus, the artificial leather provides a look and touch like that of real leather. The artificial leather is thrown and scrubbed so that texture of the artificial leather is twisted and becomes irregular and vivid like that of real leather.  
         [0000]     Sample 4  
         [0026]     A woven fabric that is of 0.7 mm thick is coated with a porous polyurethane film that is 0.4 mm thick at a quantity of 80 g/m 2  in a spotted non-overall manner. After curing, a woven fabric semi-product is made.  
         [0027]     An ultra-fine fiber sheet that is 1.1 mm thick is attached to the woven fabric semi-product by an adhesive layer provided in a dotted non-overall manner at a quantity of 80 g/m 2 . Releasing paper is coated with a dry polyurethane resin at a quantity of 300 g/m 2 , and dried and attached so that texture of the releasing paper is reprinted onto the ultra-fine fiber sheet.  
         [0028]     Surface-processing is done by providing a polyurethane chemical at a quantity of 50 g/m 2 . Ironing is done by a wheel at a temperature of 90 degrees Celsius. Thus, the artificial leather is provided with a look and touch like real leather. The artificial leather is thrown and scrubbed so that texture of the artificial leather is twisted and becomes irregular and vivid like that of real leather.  
         [0000]     Sample 5  
         [0029]     A non-woven fabric that is 0.7 mm thick is coated with a porous polyurethane film that is 0.4 mm thick at a quantity of 80 g/m 2 . After curing, a non-woven fabric semi-product is made. An ultra-fine fiber sheet that is 1.1 mm thick is attached to the non-woven fabric semi-product by an adhesive layer provided at a quantity of 80 g/m 2  in a spotted non-overall manner. Releasing paper is coated with a dry polyurethane resin at a quantity of 300 g/m 2 , and dried and attached so that texture of the releasing paper is reprinted onto the ultra-fine fiber semi-product. Surface-processing is done by providing a polyurethane chemical at a quantity of 50 g/m 2 . Ironing is done by a wheel at a temperature of 90 degrees Celsius. Thus, the artificial leather provides a look and touch like real leather. The artificial leather is thrown and scrubbed so that texture of the artificial leather is twisted and becomes irregular and vivid like that of real leather.  
         [0030]     The samples have been compared with conventional artificial leather, and results have been listed in TABLE 1 as follows.  
                                                                                                           TABLE 1                                   Ruling                                   Method   Prior Art   Sample 1   Sample 2   Sample 3   Sample 4   Sample 5                                    Texture       Plastic       Grain of   Grain of pig       Type       Leather   Grain of cattle skin   sheep skin   skin            Thickness   ASTM   1.3 +− 0.1   1.6 +− 0.1   1.2 +− 0.1   1.4 +− 0.1   1.2 +− 0.1   1.2 +− 0.1       (mm)   D1777       Weight   ASTM   630 +− 50    550 +− 30    500 +− 30    530 +− 30    500 +− 30    500 +− 30        (g/m 2 )   D3776       Touch   ASTM   0.18 to 0.22   0.30 to 0.34   0.28 to 0.31   0.30 to 0.34   0.29 to 0.32   0.28 to 0.32       (Frictional   D1894       Coefficient)       Hardness   ST 300   2.3 to 2.5   4.3 to 4.5   4.7 to 4.8   4.5 to 4.7   4.7 to 4.8   4.6 to 4.8       Texture       0.05 to 0.1    0.01 to 0.02   0.01 to 0.02   0.01 to 0.02   0.01 to 0.02   0.01 to 0.02       Fineness       (mm)       Flexibility   DIN53351   50,000   100,000   100,000   100,000   100,000   100,000       Abrasion   ASTM   1000   2000   1200   1600   1250   1240       Durability   D3884       (Sandpaper       #320)       Leather       0   10   8   10   8   8       comparison       index                  
 
         [0031]     The leather comparison index is given according the surface status and the touch, wherein “0” means the surface status and the touch are both bad, “5” means the surface status or the touch is bad, and “10” means that the surface status and the touch are both good.  
         [0032]     The present invention has been described via the detailed illustration of the embodiments. Those skilled in the art can derive variations from the embodiments without departing from the scope of the present invention. Therefore, the embodiments shall not limit the scope of the present invention defined in the claims.

Technology Classification (CPC): 3