Napped Artificial Leather Structure for Nubuck-Like Wet Feel
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Solution Overview
Problem
Existing artificial leathers fail to replicate the wet feel and consistent appearance of natural nubuck leather, with previous methods resulting in unsatisfactory surface density and color inconsistencies due to exposure of resin components.
Innovation Solution
An artificial leather with an entangled fiber mass of ultrafine fibers and a polymeric elastomer, featuring fine surface inequalities and a woven or knitted fabric lamination, is developed. The process involves producing a laminated sheet with ultrafine fibers and a shrinkable fabric, impregnating with a polymeric elastomer, and coordinating shrinkage to achieve a dense, wet feel and consistent appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a resin solution is applied to the surface of ultrafine fiber leather-like sheet to be napped, then a dense feel is realized, but the resin component is frequently exposed on the surface resulting in unfavorable appearance due to color development difference
Solution Approach 1:
The patent changes the physical and chemical parameters of the polymeric elastomer, including its molecular weight, glass transition temperature, and crosslinking density, to optimize the balance between surface density and appearance consistency. By adjusting these parameters, the resin achieves better integration with ultrafine fibers while maintaining the desired dense feel.
Solution Approach 2:
The patent develops a composite material system combining ultrafine fibers with specifically formulated polymeric elastomers. This composite structure allows the resin and fibers to work synergistically, where the elastomer provides binding and surface density while the ultrafine fibers maintain appearance consistency and prevent resin exposure.
2Adaptability or versatility
If the entangled fiber mass of ultrafine fibers is shrunk to impart stretchability, then stretchability is achieved, but the wet feel and dense appearance of nubuck-like leather are not realized
Solution Approach 1:
The patent applies local quality by creating different structural characteristics in different regions of the artificial leather. The base layer maintains stretchability through its construction, while the surface layer is specifically engineered with napped ultrafine fibers and controlled resin distribution to provide the wet feel and dense appearance of nubuck leather.
Solution Approach 2:
The patent employs preliminary action by pre-treating the ultrafine fiber sheet with polymeric elastomer solution before shrinking and napping processes. This preliminary impregnation ensures that the resin is properly distributed and bonded to fibers before the final surface structure is formed, preventing resin exposure and maintaining appearance consistency throughout subsequent processing.
3Shape
If heat shrinkable woven knitted fabric is shrunk to impart surface irregularity pattern, then surface irregularity resembling natural leather grains is achieved, but coarse surface inequalities result failing to realize nubuck-like surface feel
Solution Approach 1:
The patent transitions from two-dimensional surface patterning to three-dimensional surface structure by creating actual fiber protrusions and naps that extend outward. This dimensional change allows the surface to exhibit fine irregularities that resemble natural leather grain while maintaining overall evenness and nubuck-like characteristics through controlled fiber orientation and length.
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 artificial leather achieves a high-density napping with a wet feel similar to natural nubuck, maintaining consistency and appearance without color inconsistencies, even under load, and is suitable for various applications.
Implementation Method 1
impregnating the laminate with a polymeric elastomer resin for solidification
Implementation Method 2
a shrinkable woven or knitted fabric that are integrated into a laminate... treatment for shrinking the precursor sheet so that the overall area shrinkage rate of the precursor sheet is 12% to 50%
Data Source
Figure 1(a)~1(j)
AI summary
[Problem] The present invention provides artificial leather including an entangled fiber mass of ultrafine fibers and a polymeric elastomer and having a wet feel and an elegant consistent appearance similar to those of natural nubuck leather, and also provides a production method therefor. [Means of solution] Accordingly, the artificial leather of the present invention is an artificial leather including an entangled fiber mass of ultrafine fibers having a monofilament fineness of 0.01 dtex or more and 0.50 dtex or less and a polymeric elastomer; wherein at least one surface is napped; the cross-sectional profile curve of the napped surface has an arithmetic mean height Pa of 26 µm or more and 100 µm or less; the arithmetic mean height Pa of the cross-sectional profile curve of the opposite surface is 20% or more and 80% or less of the cross-sectional roughness Pa of the napped side; the existence frequency of asperity peaks found in the cross-sectional profile curve of the napped surface is 1.8 or more and 20 or less per 1.0 mm; and a woven or knitted fabric lamination is present near the opposite surface at a depth position of 10% or more and 50% or less.