Artificial leather, entangled web of filaments and process for producing these

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Solution Overview

Problem

Existing artificial leathers face issues with maintaining gloss due to metallic powder coating wear-off and insufficient surface properties like abrasion resistance and peeling strength, primarily due to fiber damage and unevenness during production, especially when using microfine filaments.

Innovation Solution

A method involving the production of an entangled filament web with microfine fiber-forming filaments that are temporarily fuse-bonded and then entangled without intentional cutting, using specific needle-punching techniques to form a surface layer with controlled ratios of cut ends, ensuring high entanglement and continuity of fibers for improved mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If metallic powder is coated on the surface of artificial leather to provide gloss, then the appearance quality is improved, but the gloss is lost during long use because the metallic powder easily drops off from the surface

Engineering Contradiction:
ImproveglossVSAvoidgloss retention
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The invention removes the metallic powder coating step entirely from the production process. Instead of coating metallic powder on the surface, the patent uses the inherent optical properties of the filament web structure and surface treatment to achieve gloss without any metallic coating, thereby eliminating the problem of powder drop-off

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the approach to achieving gloss from adding metallic particles to controlling the physical and chemical parameters of the surface layer itself, including the refractive index, surface smoothness, and molecular structure of the polymer matrix to achieve desired optical properties

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If staple fibers are used to produce artificial leather, then the production process is well-established, but the surface properties such as abrasion resistance and peeling strength are insufficient due to short fiber length and fiber pull-out

Engineering Contradiction:
Improveproduction processVSAvoidpeeling strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

Instead of using staple fibers as conventionally done, the invention inverts the approach by using continuous or long filament fibers throughout the entire production process. This inversion eliminates fiber end pull-out issues while maintaining production feasibility through adapted manufacturing techniques

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention employs composite filament structures with different polymer components having different solubilities, allowing the filaments to be entangled and bonded effectively while maintaining continuous fiber structure for enhanced strength and resistance to pull-out

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If microfine filament web is used as substrate, then the fineness is improved, but the entangled web with stable mass per unit area is difficult to produce and the dense feeling is poor

Engineering Contradiction:
ImprovefinenessVSAvoidmass per unit area stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The invention controls critical parameters including filament linear density, web mass per unit area, entanglement density, and bonding strength to achieve stable production of microfine filament webs with consistent properties and good dense feeling

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention implements process control mechanisms that monitor and adjust production parameters in real-time to maintain stable mass per unit area and ensure consistent quality of the microfine filament web substrate

Inventive Principle:
Principle #23Feedback

4Volume of stationary object

If filaments are cut intentionally to densify the web, then the bulkiness is improved, but the fiber damage increases and peeling strength deteriorates

Engineering Contradiction:
ImprovebulkinessVSAvoidpeeling strength
Core Design Contradiction:
Volume of stationary objectVSStrength

Solution Approach 1:

Instead of intentionally cutting filaments, the invention applies partial entanglement and bonding actions that are sufficient to achieve the desired bulkiness and density without excessive mechanical damage to the fibers, thereby maintaining peeling strength

Inventive Principle:
Principle #16Partial or excessive action

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 solution results in artificial leathers with sustained gloss and enhanced mechanical properties, such as peeling strength and bulkiness, while maintaining a natural leather-like appearance and feel, without the need for metallic coatings.

Implementation Method 1

a first entangled filament web is produced by entangling the filament web

Methodology Applied
Scientific EffectMechanical entanglement: Mechanical Force

Implementation Method 2

the filament web is hot-pressed to temporarily fuse-bond microfine fiber-forming filaments on a surface of the filament web

Methodology Applied
Scientific EffectThermal bonding: Heat Treatment

Data Source

PatentEP2402501B1Artificial leather, entangled web of filaments and process for producing these
Publication Date: 2019.10.30 KURARAY CO LTD
  • EP2402501B1 patent drawingFigure 1~2
  • EP2402501B1 patent drawingFigure 3~4
  • EP2402501B1 patent drawingFigure 5~6

AI summary

An artificial leather including a base layer and a surface layer which is formed on one of surfaces of the base layer. The base layer includes bundles of microfine filaments and an elastic polymer. The surface layer includes the microfine filaments or includes the microfine filaments and the elastic polymer. The surface layer satisfies the relationship of X/Y ≥ 1.5 wherein X is the number of cut ends of the microfine filaments which exist in a region from a surface to a 20 µm depth in a cross section of the artificial leather, Y is the number of cut ends of the microfine filaments which exist in a region from a surface to a 20 µm depth in a cross section perpendicular to the cross section for determining X, and X > Y. The artificial leather having such surface layer exhibits a sufficient gloss without coating a pigment such as metallic powder.