Porous layer structure and method for producing same
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Solution Overview
Problem
The existing method for producing polyurethane foam sheets without organic solvents results in reduced adhesion between the foam layer and the base material, failing to meet the requirements for durability and softness in urethane applications.
Innovation Solution
A porous layer structure comprising a urethane foam layer formed by foaming a specific urethane prepolymer with an isocyanate group, having a density of 0.10 to 0.60 g/cm3, and containing specific polyol components, which is applied to a water-containing base material to enhance adhesion and maintain softness and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water vapor is brought into contact with a sheet-shaped liquid mixture to cause water foaming, then organic solvent use is eliminated and energy consumption is reduced, but adhesion between the foam layer and base material is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the urethane prepolymer by specifying gel point ranges (20-30 mL, 30-50 mL, or 50 mL or more) and composition ratios (50%, 30%, or 10% or more by mass) to optimize both adhesion and foaming properties without requiring organic solvents
Solution Approach 2:
The patent uses composite polyol components with different gel points to achieve both good adhesion to base material and proper foaming characteristics, combining multiple polyol types in specific ratios to resolve the contradiction between adhesion and solvent-free foaming
2Reliability
If a polyurethane foam sheet is produced without organic solvents, then environmental sustainability is improved and processing steps are simplified, but adhesion and durability requirements are not met
Solution Approach 1:
The patent modifies the chemical parameters of the urethane prepolymer system by controlling gel points and composition ratios, enabling the material to achieve both environmental sustainability through solvent-free production and adequate adhesion/durability for practical applications
3Ease of manufacture
If the sheet-shaped liquid mixture is bonded to base material after foaming, then production process is simplified, but adhesion between layers is reduced
Solution Approach 1:
The patent applies preliminary action by pre-treating the base material with water before bonding, which creates optimal conditions for adhesion during the subsequent foaming process, ensuring good bonding strength while maintaining process simplicity
Solution Approach 2:
The patent optimizes the gel point and composition parameters of the urethane prepolymer to ensure proper adhesion to the water-containing base material, achieving both ease of manufacture and adequate bonding strength
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 provides a porous layer structure with improved adhesion and durability, achieving good softness and environmental sustainability by eliminating the use of organic solvents.
Implementation Method 1
a functional group (for example, an isocyanate group) capable of forming a crosslinked structure by reacting with water (moisture) present in the air or in a base material
Implementation Method 2
since the urethane prepolymer reacts with water (moisture) and foams, the urethane prepolymer may be used as a polyurethane foam sheet
Implementation Method 3
water vapor is brought into contact with a sheet-shaped liquid mixture to cause water foaming of the liquid mixture
Data Source
AI summary
Provided is a porous layer structure including a base material (A) and a urethane foam layer provided on the base material (A), wherein the urethane foam layer is a foam layer formed by foaming a urethane prepolymer having an isocyanate group, the urethane foam layer has a density of 0.10 to 0.60 g/cm3, and the urethane prepolymer substantially contains no volatile component and satisfies a predetermined composition.