Leather-like sheety product and production method therefor

Abstract

A leather-like sheet product comprising (a) a sheet layer ( 1 ) composed of a fiber assembly ( 1 ) of fine fibers and an elastic polymer (A) existent in a space between fibers of the fiber assembly ( 1 ), (b) a sheet layer ( 2 ) essentially composed of a fiber assembly ( 2 ) or composed of a fiber assembly ( 2 ) and an elastic polymer (C) existent in a space between fibers of the fiber assembly ( 2 ), and (c) an adhesive layer composed of an elastic polymer (B) for bonding together the sheet layer ( 1 ) and the sheet layer ( 2 ), wherein (d) the fibers of the sheet layer ( 1 ) and the fibers of the sheet layer ( 2 ) penetrate in the adhesive layer at the respective interfaces, the fibers of the sheet layer ( 1 ) are existent in the adhesive layer in a state that they are substantially not bonded to the elastic polymer (B), and the fibers of the sheet layer ( 2 ) are existent in the adhesive layer in a state that they are substantially bonded or not bonded to the elastic polymer (B); and (e) the elastic polymer (B) is existent in the adhesive layer in a state that it is bonded to at least the elastic polymer (A) contained in the sheet layer ( 1 ) at the interface, and a production process therefor. According to the present invention, there is provided a leather-like sheet which has good balance between softness and buckling resistance like natural leather and is deformed round with fine wrinkles when it is bent.

1 . A leather-like sheet product comprising (a) a sheet layer ( 1 ) composed of a fiber assembly ( 1 ) of fine fibers and an elastic polymer (A) existent in a space between fibers of the fiber assembly ( 1 ), (b) a sheet layer ( 2 ) essentially composed of a fiber assembly ( 2 ) or composed of a fiber assembly ( 2 ) and an elastic polymer (C) existent in a space between fibers of the fiber assembly ( 2 ), and (c) an adhesive layer, composed of an elastic polymer (B), for bonding together the sheet layer ( 1 ) and the sheet layer ( 2 ), wherein 
 (d) the fibers of the sheet layer ( 1 ) and the fibers of the sheet layer ( 2 ) penetrate in the adhesive layer at the respective interfaces, the fibers of the sheet layer ( 1 ) are existent in the adhesive layer in a state that they are substantially not bonded to the elastic polymer (B), and the fibers of the sheet layer ( 2 ) are existent in the adhesive layer in a state that they are substantially bonded or not bonded to the elastic polymer (B); and (e) the elastic polymer (B) is existent in the adhesive layer in a state that it is bonded to at least the elastic polymer (A) contained in the sheet layer ( 1 ) at the interface.    
     
     
         2 . The leather-like sheet product of  claim 1 , wherein the fine fibers are existent as a bundle of fine fibers in the sheet layer ( 1 ), the bundle of fine fibers penetrates in the adhesive layer at the interface of the sheet layer ( 1 ), and the elastic polymer (B) as the component of the adhesive layer is substantially not existent in the inside space of the bundle of fine fibers.  
     
     
         3 . The leather-like sheet product of  claim 1 , wherein the adhesive layer is bonded to the elastic polymer (A) at the interface of the sheet layer ( 1 ).  
     
     
         4 . The leather-like sheet product of  claim 1 , wherein the sheet layer ( 2 ) is composed of the fiber assembly ( 2 ) and the elastic polymer (C) existent in a space between fibers of the fiber assembly.  
     
     
         5 . The leather-like sheet product of  claim 4 , wherein the sheet layer ( 2 ) is composed of fine fibers and the elastic polymer (C) is existent in a space between the fibers.  
     
     
         6 . The leather-like sheet product of  claim 4 , wherein the adhesive layer is bonded to the elastic polymer (C) at the interface of the sheet layer ( 2 ).  
     
     
         7 . The leather-like sheet product of any one of  claims 1  to  6 , wherein the elastic polymer (B) of the adhesive layer is substantially not bonded to the fibers constituting the sheet layer ( 2 ) at the interface of the sheet layer ( 2 ).  
     
     
         8 . The leather-like sheet product of  claim 1 , wherein the apparent density ρ 1  (g/cm 3 ) and thickness t 1  (mm) of the sheet layer ( 1 ) and the apparent density ρ 2  (g/cm 3 ) and thickness t 2  (mm) of the sheet layer ( 2 ) satisfy the following expressions (1) to (6) at the same time:  
       0.20≦ρ 1 ≦0.48  (1) 0.20≦ρ 2 ≦0.48  (2) 0.5≦ρ 1 /ρ 2 ≦2.4  (3) 0.2≦t 1 ≦1.5  (4) 0.2≦t 2 ≦2.5  (5) 0.4≦( t   1   +t   2 )≦4.0  (6).  
     
     
         9 . The leather-like sheet product of  claim 1 , wherein the average thickness of the adhesive layer is 0.01 to 0.5 mm.  
     
     
         10 . The leather-like sheet product of  claim 1 , wherein the 100% elongation stress of a film formed only from the elastic polymer (B) of the adhesive layer is 200 to 3,000 N/cm 2 .  
     
     
         11 . The leather-like sheet product of  claim 8  which has a leather-likeness index of 0.5 to 2.0.  
     
     
         12 . The leather-like sheet product of  claim 1 , wherein the surface of the sheet product has a peel strength of 20 N/cm or more.  
     
     
         13 . A leather-like sheet product comprising (a) a sheet layer ( 1 ) composed of a fiber assembly ( 1 ) of fine fibers and an elastic polymer (A) existent in a space between fibers of the fiber assembly ( 1 ), (b) a sheet layer ( 2 ) composed of a fiber assembly ( 2 ) of fine fibers and an elastic polymer (C) existent in a space between fibers of the fiber assembly ( 2 ), and (c) an adhesive layer, composed of an elastic polymer (B), for bonding together the sheet layer ( 1 ) and the sheet layer ( 2 ), wherein 
 (d) the fibers of the sheet layer ( 1 ) and the fibers of the sheet layer ( 2 ) penetrate in the adhesive layer at the respective interfaces, the fibers of the sheet layer ( 1 ) are existent in the adhesive layer in a state that they are substantially not bonded to the elastic polymer (B), and the fibers of the sheet layer ( 2 ) are existent in the adhesive layer in a state that they are substantially not bonded to the elastic polymer (B); and (e) the elastic polymer (B) is existent in the adhesive layer in a state that it is bonded to the elastic polymer (A) contained in the sheet layer ( 1 ) at the interface and to the elastic polymer (C) contained in the sheet layer ( 2 ) at the interface.    
     
     
         14 . A leather-like sheet product comprising (a) a sheet layer ( 1 ) composed of a fiber assembly ( 1 ) of fine fibers and an elastic polymer (A) existent in a space between fibers of the fiber assembly ( 1 ), (b) a sheet layer ( 2 ) composed of a fiber assembly ( 2 ) of fine fibers and an elastic polymer (C) existent in a space between fibers of the fiber assembly ( 2 ), and (c) an adhesive layer, composed of an elastic polymer (B), for bonding together the sheet layer ( 1 ) and the sheet layer ( 2 ), wherein 
 (d) the fibers of the sheet layer ( 1 ) and the fibers of the sheet layer ( 2 ) penetrate in the adhesive layer at the respective interfaces, the fibers of the sheet layer ( 1 ) are existent in the adhesive layer in a state that they are substantially not bonded to the elastic polymer (B), and the fibers of the sheet layer ( 2 ) are existent in the adhesive layer in a state that they are substantially bonded to the elastic polymer (B); and (e) the elastic polymer (B) is existent in the adhesive layer in a state that it is bonded to at least the elastic polymer (A) contained in the sheet layer ( 1 ) at the interface and to the elastic polymer (C) contained in the sheet layer ( 2 ) at the interface.    
     
     
         15 . A process for producing a leather-like sheet product comprising the steps of: 
 bonding together a sheet layer ( 1 ′) composed of a fiber assembly of sea-island type fibers made from a mixture of at least two different polymers which differ from each other in solvent solubility and an elastic polymer (A) existent in a space between fibers of the fiber assembly and a sheet layer ( 2 ) essentially composed of a fiber assembly ( 2 ) or composed of a fiber assembly ( 2 ) and an elastic polymer (C) existent in a space between fibers of the fiber assembly ( 2 ) by an adhesive layer composed of an elastic polymer (B); and    treating the laminated sheets with a solvent which does not dissolve the island component of the sea-island type fiber and the elastic polymers but dissolves the sea component of the sea-island type fiber to dissolve and remove the sea component in order to make a fine fiber from the sea-island fiber.    
     
     
         16 . The leather-like sheet product production process of  claim 15 , wherein the sheet layer ( 2 ) is composed of fine fibers and the elastic polymer (C) existent in a space between the fibers.  
     
     
         17 . The leather-like sheet product production process of  claim 15 , wherein the sheet layer ( 2 ) is composed of sea-island type fibers made from a mixture of at least two different polymers which differ from each other in solvent solubility and the elastic polymer (C) existent in a space between the fibers.  
     
     
         18 . Artificial leather comprising the leather-like sheet product of  claim 1 ,  13  or  14 .