Natural Grain Leather

Abstract

A leather finishing process in which, in pertinent part, a warm water milling step is added after the base coat is applied to “crust” leather and cured. The warm water contains at least one dye fixation agent including but not limited to about 0.1-2.0% by weight of formic acid. Moreover, the base coat itself is an aqueous base coat containing at least two polymers such as an acrylic salt or a polyurethane salt. Between the polymeric constituents of the base coat, the acid fixation agent, and the use of the warm water milling step after the base coat has been applied and dried, a surprisingly natural feel to the leather is attained without loss of excellent adhesion, wear-resistance and other properties when the leather is completely finished.

1 . A natural grain leather comprising:
 a natural grain leather sheet having a grain surface area, said grain surface area having a plurality of hair cells therein; and   said grain surface area having a coating thereon, wherein when the natural grain leather sheet is curved over a U-shaped half pipe, said half pipe having a diameter of about 70 mm, said natural grain leather sheet folds into a series of upturns that form shallow ridges, each shallow ridge having a peak, wherein said natural grain leather has a peak to peak distance from an adjacent shallow ridge of 1 mm or less, wherein said leather withstands 30,000 cycles on a Toyota 5.9.2B test, survives 3,000 cycles on a Nissan NES M0155-15.2 test and withstands 6,000 cycles on a Mercedes DIN 53,339 test.   
   
   
       2 . The natural grain leather according to  claim 1 , wherein said coating of said grain surface area contains two polymers, wherein said two polymers are polyurethane and acrylic. 
   
   
       3 . The natural grain leather according to  claim 2 , wherein said coating has a plurality of particles, and further wherein said particles have a diameter of about 10 μm. 
   
   
       4 . The natural grain leather according to  claim 3 , wherein said natural grain leather sheet exhibits a volatile organic hydrocarbon content less than about 0.1 mg/kg. 
   
   
       5 . The natural grain leather according to  claim 4 , wherein said natural grain leather sheet exhibits a formaldehyde concentration less than about 2 mg/kg.