Base material for artificial leather and process for producing the same
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Solution Overview
Problem
Existing artificial leather substrates face challenges in simultaneously achieving a dense and elegant nap appearance, excellent color development, soft fullness, and high surface abrasion resistance, while also maintaining a balance between a smooth grain layer and a soft substrate, which are typically considered antithetical properties.
Innovation Solution
A substrate comprising a nonwoven fabric of microfine filaments with specific cross-sectional characteristics, produced through melt-spinning sea-island filaments, followed by needle-punching, moist heat-treating, and removing the sea component to create densely compacted microfine fiber bundles, allowing for the production of both nap-finished and grain-finished artificial leathers with enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If microfine fibers are used to improve appearance and hand, then appearance and hand are enhanced, but color development deteriorates
Solution Approach 1:
The invention divides the fiber structure into two distinct components: sea component (removed) and island component (microfine fibers). This segmentation allows the microfine island fibers to provide excellent appearance and hand while the bundled structure maintains sufficient color development by preventing fiber dispersion that would scatter light excessively.
Solution Approach 2:
The invention creates local quality differences within the fiber structure by forming bundles where microfine fibers are concentrated in specific regions. The bundled microfine fibers provide localized softness and elegance while the overall bundle structure maintains sufficient density for good color development.
2Ease of operation
If staple fibers are used to produce nonwoven fabric, then hand is improved, but surface abrasion resistance deteriorates
Solution Approach 1:
The invention extracts and removes the sea component from the sea-island composite fibers, leaving only the island component microfine fibers in bundled form. This extraction creates a structure with excellent hand due to the microfine fiber bundles while maintaining surface abrasion resistance through the entangled nonwoven fabric structure.
Solution Approach 2:
The invention changes the physical parameters of the fiber structure by using very fine microfine fibers (0.5-5 μm) in bundled form rather than conventional staple fibers. This parameter change in fiber fineness and bundling creates a structure that simultaneously provides soft hand and adequate abrasion resistance.
3Strength
If degree of entanglement is increased to improve surface properties, then abrasion resistance is improved, but hand deteriorates
Solution Approach 1:
The invention applies local quality by creating dense bundles of microfine fibers that provide excellent hand in the surface region, while the entanglement between bundles provides sufficient abrasion resistance. The microfine fiber bundles maintain their individual softness while being entangled together for structural integrity.
4Strength
If elastic polymer is impregnated in large amount to bind fibers, then bonding strength is improved, but hand deteriorates
Solution Approach 1:
The invention takes out and removes the sea component, eliminating the need for excessive elastic polymer impregnation. The microfine island fibers are naturally bound together in bundles through the extraction process, providing sufficient bonding strength while maintaining excellent hand without the stiffening effect of large amounts of polymer.
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 enables the creation of artificial leathers with a highly densified, smooth, and elegant appearance, excellent color development, and superior surface abrasion resistance, while maintaining a soft and bulky hand, effectively addressing the balance between grain layer and substrate properties.
Implementation Method 1
removing the sea component to create densely compacted microfine fiber bundles
Implementation Method 2
a step of entangling the nonwoven fabric by a needle-punching or spun-lacing method
Implementation Method 3
followed by needle-punching, moist heat-treating
Data Source
AI summary
A substrate for artificial leather comprising a nonwoven fabric of bundles of microfine filaments. The substrate for artificial leather simultaneously satisfies the following requirements 1 to 4: (1) the bundle of microfine filaments comprises 8 to 70 microfine filaments having a cross-sectional shape of nearly circle; (2) the bundle of microfine filaments has a cross-sectional area of 170 to 700 µm2 and a flatness of 4.0 or less; (3) on a cross section parallel to a thickness direction of the nonwoven fabric body, cross sections of the microfine fiber bundles exist in a density of 1500 to 3000/mm2; and (4) on a cross section parallel to a thickness direction of the nonwoven fabric body, gaps between the microfine fiber bundles have a size of 70 µm or less. By satisfying the requirements, the substrate for artificial leather combines high level of sensuous qualities and high level of physical properties which have been considered to be mutually exclusive.