Dyed Artificial Leather Two-Step Coloring for Uniform Shade
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Solution Overview
Problem
Existing methods for dyeing artificial leather composed of ultrafine fibers and polymeric elastomers suffer from color unevenness between the two components, particularly in light to medium colors, due to insufficient dye retention after reduction cleaning, leading to inadequate coloring of the polymeric elastomer.
Innovation Solution
A two-step dyeing process is employed, where the artificial leather is first dyed at 90°C to 140°C, followed by a second dyeing step at 60°C to 90°C with a dye concentration 0.1% to 30% of the initial concentration, using the same dye, to ensure consistent coloring of both ultrafine fibers and polymeric elastomers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional single-step dyeing method is used, then ultrafine fibers can be colored effectively, but polymeric elastomers cannot be colored sufficiently
Solution Approach 1:
The dyeing process is divided into two distinct steps: first dyeing at 90-140°C to color ultrafine fibers effectively, then second dyeing at 60-90°C with lower dye concentration (0.1%-30% of first step) to color polymeric elastomers. This segmentation allows each component to be dyed under optimized conditions, resolving the contradiction between effective ultrafine fiber coloring and polymeric elastomer coloring.
2Reliability
If reduction cleaning treatment is applied, then color fastness is improved, but dye quantity becomes insufficient for uniform coloring
Solution Approach 1:
The reduction cleaning treatment is performed as a preliminary action before the second dyeing step. This allows excess dye to be removed and color fastness to be established early, while subsequent second dyeing with additional dye ensures sufficient dye quantity remains for uniform coloring of polymeric elastomers. The preliminary cleaning prevents dye migration issues while the follow-up dyeing restores adequate dye quantity.
3Manufacturing precision
If high temperature dyeing is used, then ultrafine fibers absorb dye well, but polymeric elastomers remain poorly colored
Solution Approach 1:
The dyeing process uses dynamic temperature adjustment: high temperature (90-140°C) in the first step for effective ultrafine fiber dye absorption, then lowered temperature (60-90°C) in the second step for gradual polymeric elastomer coloring. This dynamic temperature change optimizes dye absorption for each material type at different stages, achieving both high dye absorption efficiency and color consistency across different components.
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
This method produces artificial leather with no color unevenness between ultrafine fibers and polymeric elastomers, achieving high washing fastness, rubbing fastness, and light fastness, even in red colors, resulting in a product with excellent surface quality and commercial value.
Implementation Method 1
a first dyeing step in which artificial leather constituted mainly of a fibrous base containing ultrafine fibers with a filament fineness of 2 decitex or less and a polymeric elastomer is dyed using a dye
Implementation Method 2
treated with a reduction agent to reduce and decompose the excess disperse dye, thereby decolorizing the elastic polymer parts exposed in the surface of the artificial leather base
Implementation Method 3
subjected to oxidation cleaning with an oxidizing agent as required
Data Source
AI summary
The present invention provides dyed artificial leather including ultrafine fibers and a polymeric elastomer, having no color unevenness between the ultrafine fibers and the polymeric elastomer, and having good surface quality with high washing fastness, rubbing fastness, and light fastness, and also provides a production method therefor. The dyed artificial leather according to the invention includes a fibrous base containing ultrafine fibers with a filament fineness of 2 decitex or less and a polymeric elastomer, and characterized in that the lightness difference ΔL* between the ultrafine fibers and the polymeric elastomer represented by the following equation meet the requirement of -16≤ΔL*≤5: ΔL*=average lightness L*of ultrafine fibers−average lightness L*of polymeric elastomer. The production method for dyed artificial leather according to the present invention is characterized by including a first dying step in which artificial leather constituted mainly of a fibrous base containing ultrafine fibers with a filament fineness of 2 decitex or less and a polymeric elastomer is dyed using a dye and a subsequent second dyeing step performed at a dye concentration that is 0.1% to 30% of the dye concentration (owf) in the first dyeing step.