Leather and process for its production

• US 6,746,774 B1
• Filed: 09/05/2000
• Issued: 06/08/2004
• Est. Priority Date: 09/13/1999
• Status: Expired due to Fees

• Current Assignee: BASF SE
• Original Assignee: Philipp Schaefer
• Inventors: Schaefer, Philipp
• Primary Examiner(s): Zirker, Daniel
• Assistant Examiner(s): Chang, Victor S
• Application Number:
  US09/655,284
• Time in Patent Office: 1,372 Days
• Field of Search: 428/423.4, 428/313.3, 428/313.5, 428/314.4, 428/314.8, 428/306.6, 428/473, 428/151, 428/323, 428/87, 428/95, 428/52
• US Class Current: 428/423.4
• CPC Class Codes: B32B 17/10 of synthetic resin
• CPC Class Codes: B32B 2266/0264 Polyester
• CPC Class Codes: B32B 2266/0278 Polyurethane
• CPC Class Codes: B32B 2355/02 ABS polymers, i.e. acrylonitrile-butadiene-styrene polymers
• CPC Class Codes: B32B 2367/00 Polyesters, e.g. PET, i.e. polyethylene terephthalate
• CPC Class Codes: B32B 2375/00 Polyureas; Polyurethanes
• CPC Class Codes: B32B 5/18 characterised by features of a layer of foamed material
• CPC Class Codes: C14C 11/006 using polymeric products of isocyanates (or isothiocyanates) with compounds having active hydrogen
• CPC Class Codes: Y10T 428/169 Sections connected flexibly with external fastener
• CPC Class Codes: Y10T 428/23921 With particles
• CPC Class Codes: Y10T 428/23979 Particular backing structure or composition
• CPC Class Codes: Y10T 428/24438 Artificial wood or leather grain surface
• CPC Class Codes: Y10T 428/249955 Void-containing component partially impregnated with adjacent component
• CPC Class Codes: Y10T 428/249971 Preformed hollow element-containing
• CPC Class Codes: Y10T 428/249972 Resin or rubber element
• CPC Class Codes: Y10T 428/249976 Voids specified as closed
• CPC Class Codes: Y10T 428/249977 Specified thickness of void-containing component [absolute or relative], numerical cell dimension or density
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/31558 Next to animal skin or membrane

Abstract

In order to provide leather with the desired cushioning properties and desirable soft handling properties, especially a grained leather with a grain structure on its upper surface, or a split leather with a surface finish, even if this leather is of minimal thickness, a foam layer is created on the non-visible underside surface of the leather. This foam layer is formed by applying a liquid plastic material containing means to create the foam and is subsequent solidified by removal of the solvent.

Claims

1. A leather assembly, comprising:

a leather selected from the group consisting of a grained leather showing a grain structure on an upper surface thereof and a split leather with a surface finish; and

a coating layer on a non-visible underside surface of said leather, said coating layer being a foam layer formed by applying a liquid plastic dispersion with a solvent and subsequently setting the coating layer by removing the solvent and forming a solidified dispersion;

said foam layer having closed cells and open cells, with said closed cells formed of hollow microspheres comprising gas-tight shells of plastic enclosing a gas, and open cells filling interspaces between said closed cells;

said solidified dispersion having a hardness of less than 45 Shore A units and a density of less than 0.3 g/cm³; and

said solidified dispersion enclosing fibers projecting from said underside surface of said leather, with individual enclosed fibers or fiber bundles individually projecting from said underside surface of said leather.

2. The leather assembly according to claim 1, wherein said foam layer has a density of substantially 0.3 g/cm³.

3. The leather assembly according to claim 1, wherein said foam layer has at least 85% of closed cells.

4. The leather assembly according to claim 1, wherein said foam layer is formed in such a manner that it becomes at least partially impregnated into the leather.

5. The leather assembly according to claim 1, wherein said foam layer consists of a solidified dispersion containing a cross linking agent and a material selected from the group consisting of polyurethane and polyacrylic acid ester.

6. The leather assembly according to claim 1, wherein said foam layer consists of a solidified dispersion of polybutadiene and/or polystyrene and/or chlorinated rubber.

7. The leather assembly according to claim 1, wherein said foam layer is formed through the incorporation of tiny air bubbles into a plastic material forming the foam.

8. The leather assembly according to claim 1, wherein a thickness of the foam layer is less than 0.3 mm.

9. The leather assembly according to claim 1, wherein said foam layer has a thickness of 0.3 mm and the thickness, when subjected to a load factor of 1 kg/cm²/h, is decreased by a maximum of 20%, and will, on removing the load, return to its original thickness.

10. The leather assembly according to claim 1, wherein said foam layer on the side not bonded to said leather, is covered by sheeting selected from the group consisting of textile cloth, leather, and fleece material.

11. The leather assembly according to claim 1, wherein said leather has a thickness of less than 1.5 mm.