Sheet-like material and method for producing same
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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, wear resistance, and texture, often resulting in hard textures or requiring additional processing steps.
Innovation Solution
A method involving a polyurethane liquid with a foaming agent and thermosensitive coagulant, containing hydrophilic groups like quaternary amine salts or polyethylene glycol, is applied to a fibrous base, forming a porous structure with controlled pore diameters and coagulation temperatures to create a flexible, wear-resistant sheet-like material.
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 friendliness is improved, but the texture becomes hard
Solution Approach 1:
The patent applies porous materials by incorporating a foaming agent into the water-dispersed polyurethane composition. During the curing process, the foaming agent generates gas bubbles that create a porous structure within the polyurethane matrix. This porous structure reduces the density and hardness of the coating film, thereby softening the texture while maintaining the environmental benefits of using water-based polyurethane instead of organic solvents.
Solution Approach 2:
The patent employs parameter changes by carefully controlling the molecular weight, functional group content, and crosslinking density of the water-dispersed polyurethane. By adjusting these parameters, particularly using polyurethane with specific hydrophilic group contents (0.5-5.0 mmol/g) and molecular weights (10,000-100,000), the coating film achieves optimal balance between flexibility and adhesion, preventing excessive hardness while maintaining coating integrity.
2Shape
If flexible polyurethane with low crystallinity is used, then texture flexibility is improved, but wear resistance deteriorates
Solution Approach 1:
The patent applies composite materials by combining water-dispersed polyurethane with a foaming agent and optional fillers or reinforcing agents. The resulting composite coating structure integrates the flexibility benefits of low-crystallinity polyurethane with the mechanical strength provided by the crosslinked network and porous structure. This composite approach enables simultaneous achievement of soft texture and high wear resistance, resolving the contradiction between flexibility and durability.
3Area of stationary object
If polyurethane is added to fibrous base, then coating coverage is improved, but migration occurs causing uneven distribution
Solution Approach 1:
The patent applies the intermediary principle by using water as the dispersion medium instead of organic solvents. The water-based dispersion system acts as an intermediary that allows polyurethane particles to be uniformly distributed throughout the coating composition before application. This water-mediated dispersion prevents premature aggregation and migration of polyurethane, ensuring even coverage and uniform distribution on the fibrous base while maintaining environmental friendliness.
4Strength
If polyurethane strongly grasps entangled portions of fibers, then adhesion is improved, but texture becomes hard
Solution Approach 1:
The patent applies porous materials by incorporating a foaming agent into the water-dispersed polyurethane composition. During the curing process, the foaming agent generates gas bubbles that create a porous structure within the polyurethane matrix. This porous structure reduces the density and hardness of the coating film, thereby softening the texture while maintaining the environmental benefits of using water-based polyurethane instead of organic solvents.
Solution Approach 2:
The patent employs parameter changes by carefully controlling the molecular weight, functional group content, and crosslinking density of the water-dispersed polyurethane. By adjusting these parameters, particularly using polyurethane with specific hydrophilic group contents (0.5-5.0 mmol/g) and molecular weights (10,000-100,000), the coating film achieves optimal balance between flexibility and adhesion, preventing excessive hardness while maintaining coating integrity.
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 produces a sheet-like material with an elegant appearance, high wear resistance, and flexible texture, preventing surface weight loss from abrasion while maintaining good piloerection and grindability.
Implementation Method 1
the polyurethane liquid has thermosensitive coagulability
Implementation Method 2
the polyurethane liquid contains a foaming agent
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 which is characterized by 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 sheet-like material is also characterized in that 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, which is characterized in that 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.