Porous Polyurethane Sheet Material for Soft Wear-Resistant Texture
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Solution Overview
Problem
Existing methods for producing leathery sheet-like materials without organic solvents fail to achieve a balance between flexibility and wear resistance, often resulting in hard textures or requiring additional processing steps that decrease productivity.
Innovation Solution
A sheet-like material is produced using a fibrous base with extra-fine fibers and water-dispersed polyurethane containing a foaming agent, which forms a porous structure with polyurethane having a 100% modulus of 3-8 MPa, providing both flexibility and high wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water-dispersed polyurethane is used to replace organic solvent type polyurethane, then environmental harm is reduced, but the texture becomes hard
Solution Approach 1:
The patent applies porous materials by incorporating a foaming agent into the water-dispersed polyurethane coating composition. This creates a porous structure within the polyurethane layer that reduces density and softens the texture, while maintaining the environmental benefit of using water instead of organic solvents. The porous structure is achieved through gas bubbles formed during the curing process.
Solution Approach 2:
The patent employs parameter changes by adjusting the 100% modulus of the polyurethane to a specific range (2-10 MPa) and controlling the pore diameter (10-200 μm) and content (30-70% by volume) to achieve the desired balance between texture softness and wear resistance. These parameter optimizations allow the material to be both soft to the touch and durable.
2Shape
If flexible polyurethane with low crystallinity is used to achieve flexible texture, then texture softness is improved, but wear resistance deteriorates
Solution Approach 1:
The porous structure created by the foaming agent provides flexibility and softness to the polyurethane layer while the polyurethane matrix maintains adequate wear resistance. The pores reduce the density and rigidity of the material, making it more flexible, while the continuous polyurethane phase preserves protective properties.
Solution Approach 2:
The patent creates a composite structure combining polyurethane with gas bubbles (foam structure). This composite material exhibits properties that differ from pure polyurethane - specifically, reduced rigidity and increased flexibility due to the foam structure, while maintaining wear resistance through the polyurethane matrix.
3Strength
If association type thickener is added to water-dispersed polyurethane to form porous structure, then grasping force at fiber entangled points is reduced, but stickiness is caused requiring cleaning steps
Solution Approach 1:
The patent extracts the thickening function from the coating composition by removing association type thickeners. Instead, it uses the foaming agent to create the desired porous structure without causing stickiness or requiring additional cleaning steps. This eliminates the harmful side effects while achieving the structural goal.
Solution Approach 2:
The foaming agent acts as an intermediary substance that achieves the desired porous structure without causing stickiness. Unlike association type thickeners that remain dissolved and cause adhesion problems, the foaming agent creates gas bubbles that escape or remain as harmless pores, avoiding contamination and cleaning requirements.
4Shape
If foam stabilizer is added to polyurethane for mechanical foaming, then porous structure is formed, but foam may disappear during impregnation
Solution Approach 1:
The patent replaces mechanical foaming (which requires foam stabilizers and complex equipment) with a chemical foaming approach. The foaming agent chemically generates gas bubbles within the coating composition, creating a stable porous structure without relying on mechanical agitation or foam stabilizers that may fail during impregnation.
Solution Approach 2:
The patent optimizes parameters including pore diameter (10-200 μm), pore content (30-70% by volume), and polyurethane 100% modulus (2-10 MPa) to ensure the porous structure forms reliably and maintains stability during the impregnation and curing processes, preventing foam collapse.
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 method results in a sheet-like material with an elegant appearance, high wear resistance, and good texture, preventing weight loss from abrasion while maintaining flexibility and ease of napping.
Implementation Method 1
water-dispersed polyurethane liquid that contains a foaming agent... forms a porous structure with polyurethane
Implementation Method 2
the fibrous base thus obtained is immersed in water or an aqueous organic solvent solution that is a non-solvent for polyurethane to achieve wet coagulation of polyurethane
Data Source
AI summary
Disclosed is a sheet-like material which is produced by an environmentally friendly procedure and has an elegant appearance with piloerection, good wear resistance and good texture. Specifically disclosed is a sheet-like material containing a water-dispersed polyurethane within a fibrous base that contains extra-fine fibers having an average single fiber diameter of 0.3-7 um. The inside of the water-dispersed polyurethane is provided with pores each having a diameter of 10-200 um. Also specifically disclosed is a method for producing a sheet-like material by applying a polyurethane liquid to a fibrous base, wherein the polyurethane liquid is a water-dispersed polyurethane liquid that contains a foaming agent and a dry film of the polyurethane that constitutes the polyurethane liquid has a 100% modulus of 3-8 MPa.