Napped Artificial Leather Surface Finish for Rub Color Fastness

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Solution Overview

Problem

Napped artificial leathers with ultrafine fibers suffer from low color fastness to rubbing, especially when colored dark, and existing treatments to improve this often compromise the quality of the touch or are not effective.

Innovation Solution

A napped artificial leather with ultrafine fibers is treated with particles of a fatty acid amide-based compound having a specific size and melting point, which are attached to the fiber surfaces, enhancing color fastness to rubbing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a napped artificial leather including a fiber-entangled body of ultrafine fibers is dyed in dark color, then the appearance quality is improved, but the color fastness to rubbing is reduced

Engineering Contradiction:
Improvecolor depthVSAvoidcolor fastness to rubbing
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent introduces a specific finishing agent as an intermediary substance between the dyed ultrafine fibers and the rubbing surface. This finishing agent forms a protective layer that prevents color transfer while maintaining the dark color appearance, thus resolving the contradiction between color depth and color fastness to rubbing

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical and physical parameters of the fiber surface by applying specific finishing treatments. This modifies the surface properties to reduce color migration during rubbing, allowing dark colors to be maintained while improving color fastness

Inventive Principle:
Principle #35Parameter changes

2Reliability

If polyolefin such as paraffin wax is applied to the napped surface to improve color fastness to rubbing, then the color fastness is improved, but the quality of touch is reduced due to tackiness

Engineering Contradiction:
Improvecolor fastness to rubbingVSAvoidquality of touch
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the chemical composition and physical state parameters of the finishing agent. Instead of using conventional polyolefin waxes that create tackiness, the patent employs finishing agents with specific molecular structures and melting points that provide color fastness while maintaining a non-tacky, high-quality touch

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite finishing formulations that combine multiple components with complementary properties. This composite approach achieves both color fastness to rubbing and desirable tactile qualities, avoiding the tackiness problem associated with single-component polyolefin applications

Inventive Principle:
Principle #40Composite materials

3Reliability

If fatty acid amide is applied and dried to improve color fastness to rubbing, then the color fastness should be improved, but the fatty acid amide attaches in film form rather than particles, reducing effectiveness

Engineering Contradiction:
Improvecolor fastness to rubbingVSAvoidattachment form control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent precisely controls the physical parameters of the fatty acid amide application process, particularly the particle size distribution and drying conditions. By maintaining particle sizes within 0.1 to 10 μm and controlling drying temperature below the melting point, the patent ensures particle attachment rather than film formation, achieving both color fastness and manufacturing precision

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates local quality differences in the finishing agent application. The fatty acid amide is applied as discrete particles distributed locally on the fiber surfaces rather than forming a continuous film, providing effective color fastness while maintaining the napped surface characteristics

Inventive Principle:
Principle #3Local quality

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 treated napped artificial leather exhibits excellent color fastness to rubbing, maintaining a high-quality appearance and touch, even under high temperatures.

Implementation Method 1

a napped artificial leather which includes particles of a fatty acid amide-based compound that are attached to surfaces of the ultrafine fibers

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

the napped artificial leather has excellent color fastness to rubbing... particles of a fatty acid amide-based compound that are attached to surfaces of the ultrafine fibers

Methodology Applied
Scientific EffectFriction reduction: Friction

Data Source

PatentEP3904591B1Napped artificial leather and method for producing the same
Publication Date: 2026.02.18 KURARAY CO LTD
  • EP3904591B1 patent drawingFigure 1

AI summary

Disclosed is a colored napped artificial leather including: a fiber-entangled body including ultrafine fibers having an average single fiber fineness of 0.5 dtex or less; and an elastic polymer impregnated into the fiber-entangled body, the napped artificial leather having, at least on one side thereof, a napped surface formed by napping the ultrafine fibers, wherein the napped artificial leather further includes particles of a fatty acid amide-based compound that are at least attached to surfaces of the ultrafine fibers and that have an average particle size of 0.1 to 10 µm.