Synthetic Leather Substrate Structure for Soft Feel and Abrasion Resistance

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Solution Overview

Problem

Existing artificial leathers face challenges in simultaneously achieving a dense, elegant appearance, excellent color development, soft hand feel, and high surface abrasion resistance, particularly in raised and grain-finished types, due to issues with fiber fineness, entanglement, and elastic polymer distribution.

Innovation Solution

A substrate comprising microfine fiber bundles with specific cross-sectional areas and densities, produced through melt-spinning sea-island fibers, three-dimensional entanglement, and elastic polymer impregnation, followed by removal of the sea component to create a highly densified and smooth surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the fiber fineness is decreased to improve appearance and hand, then the color development deteriorates

Engineering Contradiction:
Improveappearance and handVSAvoidcolor development
Core Design Contradiction:
ShapeVSIllumination intensity

Solution Approach 1:

The patent changes the physical parameters of fibers by using ultrafine fibers (0.01-0.05 μm diameter) instead of conventional fine fibers, and controls the fiber bundle structure (10-100 fibers per bundle) to achieve both excellent appearance/hand and color development simultaneously

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure combining ultrafine fibers with elastic polymers in specific ratios and arrangements, forming a nonwoven fabric that achieves multiple properties: the ultrafine fibers provide appearance and hand, while the composite structure with elastic polymer maintains color development and improves surface abrasion resistance

Inventive Principle:
Principle #40Composite materials

2Reliability

If the degree of entanglement is increased to improve surface properties, then the hand deteriorates

Engineering Contradiction:
Improvesurface abrasion resistanceVSAvoidhand
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies different degrees of entanglement to different regions: the raised surface maintains lower entanglement (5-20 times) to preserve soft hand and fullness, while the interior structure has higher entanglement to ensure surface abrasion resistance and structural integrity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent precisely controls the entanglement parameter (5-20 times for raised surface) to achieve the optimal balance between surface properties and hand, avoiding excessive entanglement that would harden the material

Inventive Principle:
Principle #35Parameter changes

3Strength

If an elastic polymer is impregnated in a large amount to bind fibers strongly, then the hand deteriorates

Engineering Contradiction:
Improvebonding/peeling strengthVSAvoidhand
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent optimizes the elastic polymer content parameter (5-30 parts by mass per 100 parts of nonwoven fabric) and molecular weight (10,000-100,000) to achieve sufficient bonding strength while maintaining soft hand and fullness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent distributes elastic polymer non-uniformly: higher concentration at fiber entanglement points and interface regions for strength, lower concentration in bulk regions to preserve softness and hand

Inventive Principle:
Principle #3Local quality

4Ease of operation

If staple fibers are used to produce nonwoven fabric, then the hand is improved, but the surface abrasion resistance deteriorates

Engineering Contradiction:
ImprovehandVSAvoidsurface abrasion resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the fiber length parameter from conventional staple fibers to ultrafine fibers with specific length (10-50 mm) and diameter (0.01-0.05 μm), and controls the number of fibers per bundle (10-100) to achieve both soft hand and high surface abrasion resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure where ultrafine fibers form dense bundles (10-100 fibers per bundle) that resist abrasion, while the overall nonwoven fabric structure maintains softness and hand

Inventive Principle:
Principle #40Composite materials

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 production of artificial leathers with a smooth, elegant appearance, excellent color development, and enhanced surface abrasion resistance, matching the quality of natural leathers, while maintaining a soft hand feel and high bonding/peeling strength.

Implementation Method 1

an elastic polymer impregnated into the nonwoven fabric body

Methodology Applied
Scientific EffectImpregnation:

Implementation Method 2

convert composite fibers such as sea-island fibers and multi-layered fibers to microfine fiber bundles by splitting or removal of a polymer component by decomposition or extraction

Methodology Applied
Scientific EffectExtraction: Liquid-Liquid Extraction

Implementation Method 3

a nonwoven fabric body made of microfine fiber bundles... produced through melt-spinning sea-island fibers, three-dimensional entanglement

Methodology Applied
Scientific EffectEntanglement:

Data Source

PatentEP1970486B1Base for synthetic leather and synthetic leathers made by using the same
Publication Date: 2012.11.14 KURARAY CO LTD

AI summary

A substrate for artificial leathers, comprising a nonwoven fabric, body made of microfine fiber bundles and an elastic polymer impregnated therein. The substrate for artificial leathers simultaneously satisfies the following requirements 1 to 4: (1) each of the microfine fiber bundles contains 6 to 150 bundled microfine long fibers in average; (2) a cross-sectional area of the microfine long fibers constituting the microfine fiber bundles is 27 µm2 or less, and 80% or more of the microfine long fibers has a cross-sectional area of from 0.9 to 25 µm2; (3) an average cross-sectional area of the microfine fiber bundles is from 15 to 150 µm2; and (4) on a cross sections parallel to a thickness direction of the nonwoven fabric body, cross sections of the microfine fiber bundles exist in a density of from 1000 to 3000/mm2 in average. The raised artificial leathers and grain-finished artificial leathers made from the substrate for artificial leathers are excellent in the properties which are hitherto difficult to be combined.