Napped Artificial Leather Composition for Uniform Dark Color
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Solution Overview
Problem
Conventional napped artificial leathers with dark colors often exhibit dichromatic impressions due to differences in color tone between spun-dyed fibers and undyed elastic polymers, leading to reduced product quality and increased production complexity when producing multiple brands in small quantities.
Innovation Solution
A napped artificial leather with ultrafine fibers containing 0.5 mass % or more of a pigment and an elastic polymer containing 0 to 0.01 mass % of a pigment, where the napped surface has a lightness L* value of 25 or less and the elastic polymer occupies 0.5% or less of the total surface area, eliminating the need for dyeing and reducing color adjustment operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the napped artificial leather is dyed with a large amount of dye to reduce the dichromatic impression, then the color uniformity is improved, but the fastness of the napped artificial leather is reduced
Solution Approach 1:
The elastic polymer is preliminarily colored with a pigment before the napping process, so that when the ultrafine fibers are raised to the surface, both the fibers and the polymer exhibit the same color tone, eliminating the dichromatic impression without requiring excessive dyeing later that would compromise fastness
2Ease of manufacture
If an elastic polymer colored with a pigment in advance is used to produce artificial leathers under multiple brands in small quantities, then the color adjustment operation is simplified, but the productivity is reduced due to switching pigment concentrations
Solution Approach 1:
The invention changes the concentration parameter of the pigment in the elastic polymer emulsion to 0.01 mass% or less, which is sufficient to provide color tone without requiring frequent adjustments for different brands, thereby maintaining productivity while simplifying color adjustment operations
Data Source
AI summary
Disclosed is a napped artificial leather napped including: a non-woven fabric that is an entangle body of ultrafine fibers; and an elastic polymer impregnated into the non-woven fabric, the napped artificial leather having, at least on one side thereof, a napped surface formed by napping the ultrafine fibers, wherein the ultrafine fibers contain 0.5 mass % or more of a pigment (A), the elastic polymer contains 0 to 0.01 mass % of a pigment (B), and the ultrafine fibers and the elastic polymer are undyed; the napped surface has a lightness L* value of 25 or less in a color coordinate space (L*a*b* color space); and a ratio of an area occupied by the elastic polymer, observed on the napped surface, to a total area of an area occupied by the ultrafine fibers and the area occupied by the elastic polymer is 0.5% or less.