Coated Leather with Micro-Indentations for Nubuck Durability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Genuine nubuck leather suffers from a loss of tactile appeal and becomes greasy and prone to staining, with insufficient lightfastness and abrasion resistance, making it unsuitable for high-wear applications like vehicle interiors and safety shoes.
Innovation Solution
A coated leather with smooth, semispherical micro-indentations and a soft polyurethane exterior layer that mimics the appearance and feel of nubuck leather, while being resistant to dirt, water, and wear, using a cross-linked polyurethane dispersion with a crystalline structure and polysiloxane additives for enhanced durability and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If genuine nubuck leather is used to achieve a matte surface and pleasant touch, then the visual appearance and haptics are improved, but the leather becomes greasy and prone to staining with use
Solution Approach 1:
The patent changes the chemical composition parameters of the leather surface by applying a coating containing fluorinated compounds and silicon oxide particles. This modifies the surface energy and porosity parameters, creating a hydrophobic and oleophobic effect that prevents dirt and water penetration while maintaining the nubuck-like matte appearance and tactile properties without the greasy deterioration of genuine nubuck leather.
Solution Approach 2:
The patent creates a composite surface structure by combining the natural leather substrate with a synthetic coating layer containing fluorinated polymers, silicon oxide particles, and other additives. This composite material integrates the aesthetic qualities of nubuck leather with the protective properties of fluorinated coatings, achieving both visual appeal and resistance to soiling, staining, and water damage.
2Shape
If genuine nubuck leather is used to achieve a fine-grained matte surface, then the visual appearance is improved, but the lightfastness and abrasion resistance are insufficient
Solution Approach 1:
The patent modifies the mechanical and chemical parameters of the leather surface through coating application. The fluorinated compound-based coating forms a protective matrix that enhances abrasion resistance and lightfastness while preserving the fine-grained matte surface structure. The coating creates a barrier that protects the underlying leather fibers from mechanical wear and UV degradation.
Solution Approach 2:
The patent develops a composite surface system combining treated leather with a fluorinated polymer coating containing silicon oxide particles. This composite structure provides the aesthetic fine-grained matte appearance of nubuck leather while the fluorinated coating layer supplies enhanced mechanical strength, abrasion resistance, and UV stability, preventing the deterioration that occurs in genuine nubuck leather.
3Shape
If a foam coating is applied to create a nubuck-like surface, then the visual appearance is improved, but the process becomes cumbersome and expensive with abrasive dust creation
Solution Approach 1:
Instead of using complex foam coatings that require grinding to achieve the nubuck effect, the patent applies a fluorinated compound-based coating that directly forms the desired matte surface structure. This coating process copies the aesthetic outcome of grinding without requiring the mechanical abrasion process, thereby simplifying manufacturing, reducing costs, and eliminating abrasive dust creation while maintaining the nubuck-like visual appearance.
4Shape
If polyurethane foils with open-celled structure are laminated to create a nubuck effect, then the visual appearance is improved, but the surface becomes prone to dirt penetration and lacks abrasion resistance
Solution Approach 1:
The patent changes the porosity and surface energy parameters of the coating by incorporating fluorinated compounds and silicon oxide particles. These additives modify the open-celled polyurethane structure to create a hydrophobic and oleophobic surface that repels dirt and water, preventing penetration into the cellular structure while maintaining the nubuck-like visual appearance and tactile properties.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The coated leather maintains a matte appearance and pleasant touch, offering excellent abrasion resistance, water repellency, and self-cleaning properties, meeting the stringent requirements of the vehicle and safety shoe industries without the drawbacks of genuine nubuck leather.
Implementation Method 1
a cross-linked polyurethane dispersion with a crystalline structure
Implementation Method 2
a cross-linked polyurethane dispersion with a crystalline structure
Implementation Method 3
excellent abrasion resistance, water repellency, and self-cleaning properties
Implementation Method 4
resistant to dirt, water, and wear
Data Source
AI summary
A coated leather, in particular split cowhide leather, has a preferably nubuck-like appearing surface structure. The coating is formed with a surface layer formed with a mechanically and moisture-stable polymer and bonded to the surface of the leather or split leather by a polymer-based bonding layer. The outer layer is notable for inner smoothness and is formed with soft polyurethane. It includes in the non-embossed region microdepressions which are essentially closed in the direction of the leather but are open towards the outside, have an internal width of less than 130 μm and are arranged close-packed to each other in the manner of soapy foam cells. The microdepressions are each separately bounded by thin mutually crosslinked stays which have on the outside a matt or finely fibrous fine-roughness structure surface, and have an essentially semispherical-shaped concave inner surface which faces outward and is smooth. The coating may include two or more layers that are riveted to each other by way of pins or the like that are anchored in pores.