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 during production, especially when using staple fibers, and the challenges of producing high-quality microfine filament webs with stable mass per unit area and bulkiness.
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 a high ratio of cut ends, achieving a glossy finish and enhanced mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If metallic powder is coated on the surface of artificial leather, then gloss appearance is improved, but the gloss is lost during long use because the powder drops off easily
Solution Approach 1:
The invention extracts and removes the metallic powder coating step entirely, replacing it with an intrinsic glossy surface structure formed by densely packed microfine filaments. The surface layer comprises microfine filaments with a density of 10000 to 50000 filaments per mm², creating natural gloss without any coating that could drop off.
Solution Approach 2:
The invention uses composite filaments consisting of a sea component (water-soluble polymer) and an island component (fiber-forming polymer) in a sea-island structure. This composite structure allows the filaments to maintain continuity and integrity while providing the desired surface properties and gloss.
2Ease of manufacture
If staple fibers are used for artificial leather production, then production process is conventional, but fiber damage occurs during production leading to insufficient peeling strength and abrasion resistance
Solution Approach 1:
The invention changes the fundamental parameter from staple fiber to continuous filament, and specifically uses microfine filaments with a fineness of 0.01 to 0.5 dtex. This parameter change eliminates fiber damage during production while maintaining ease of manufacture through a simplified process that doesn't require carding or extensive opening operations.
Solution Approach 2:
Instead of using staple fibers and accepting the inherent damage during processing, the invention inverts the approach by using continuous filaments that inherently avoid damage. The production process is inverted from a multi-step staple fiber handling process to a more direct filament web formation and entanglement process.
3Manufacturing precision
If microfine filaments are used for artificial leather, then surface quality and gloss are improved, but it is difficult to produce an entangled web with stable mass per unit area
Solution Approach 1:
The invention applies local quality by creating a surface layer with a specific density range (10000 to 50000 filaments per mm²) that is different from the base layer. This localized control of filament density ensures both stable mass per unit area and high surface quality with gloss, as the surface layer is specifically optimized for these properties.
Solution Approach 2:
The invention performs preliminary action by forming a filament web with controlled architecture before entanglement. The web is designed with specific filament density and arrangement that, when entangled, produces a stable mass per unit area. This preliminary structuring ensures consistent surface quality and gloss while maintaining stability in mass per unit area.
4Strength
If filaments are used instead of staples, then strength and shape stability are improved, but bulkiness is poor and hand becomes cloth-like
Solution Approach 1:
The invention transitions from one-dimensional staple fibers to two-dimensional microfine filaments with extremely small cross-sectional dimensions (0.01 to 0.5 dtex). This dimensional change allows the filaments to pack densely while maintaining flexibility and bulkiness, creating a leather-like hand feel rather than a cloth-like appearance.
Solution Approach 2:
The invention changes the fineness parameter to an extremely small range (0.01 to 0.5 dtex), which is much finer than conventional filaments. This parameter change enables the filaments to provide both the strength and shape stability of continuous fibers and the bulkiness and soft hand feel similar to natural leather, avoiding the cloth-like appearance of coarser filaments.
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 improved peeling strength, maintaining the benefits of filament continuity while ensuring production efficiency and surface quality, comparable to natural leather in terms of drapeability and appearance.
Implementation Method 1
a step in which the fibers are entangled to one another by a needle-punching, etc. to form an entangled non-woven fabric
Implementation Method 2
a step in which a solution of an elastic polymer such as polyurethane is impregnated into the entangled non-woven fabric
Implementation Method 3
the production of an entangled filament web with microfine fiber-forming filaments that are temporarily fuse-bonded and then entangled
Data Source
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.