Method for manufacturing sheet-like product
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Solution Overview
Problem
Existing methods for producing sheet-like articles using water-dispersed polyurethane often result in materials that deteriorate physically when wet, and struggle to maintain the original texture and surface quality post-crosslinking, while also relying on organic solvents harmful to the environment.
Innovation Solution
A method involving the impregnation of a fibrous base material with water-dispersed polyurethane, followed by coagulation and the addition of a crosslinking agent, with the crosslinking reaction occurring after the formation of the polyurethane structure, allowing for high moist heat resistance and maintaining the original texture and surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a water dispersed polyurethane liquid is used instead of organic solvent based polyurethane, then environmental harm is reduced, but the physical properties deteriorate when wet
Solution Approach 1:
The patent applies preliminary action by adding a crosslinking agent to the water dispersed polyurethane liquid before impregnation, and then performing heat treatment after impregnation to trigger the crosslinking reaction. This preliminary preparation of the crosslinking agent and subsequent activation resolves the contradiction by pre-establishing the conditions for crosslinking, which then provides wet resistance without requiring organic solvents during the impregnation process
2Reliability
If a crosslinking agent is added to water dispersed polyurethane before impregnation, then wet resistance is improved, but the texture becomes stiff
Solution Approach 1:
The patent applies preliminary action by adding the crosslinking agent to the water dispersed polyurethane liquid before impregnation of the fibrous base material. This allows the crosslinking agent to be uniformly distributed and positioned within the polyurethane structure before the material is applied, enabling subsequent crosslinking that provides wet resistance while maintaining texture control through proper timing and distribution
Solution Approach 2:
The patent applies parameter changes by controlling the heat treatment temperature and duration to optimize the crosslinking reaction. By adjusting these thermal parameters, the patent achieves sufficient crosslinking for wet resistance while preventing excessive crosslinking that would cause stiffening, thus resolving the contradiction between wet resistance and texture softness
3Stability of the object's composition
If crosslinking is performed after coagulation, then the original texture is maintained, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies merging by combining the crosslinking step with the existing heat treatment step that is already required for coagulation of the polyurethane. Instead of adding a separate crosslinking process, the patent utilizes the heat treatment temperature and duration to simultaneously achieve both coagulation and crosslinking, thereby maintaining the original texture while avoiding additional process complexity
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 sheet-like articles with enhanced moist heat resistance and preserved texture and surface quality, using an environmentally friendly process that avoids the use of organic solvents.
Implementation Method 1
a fibrous base material is impregnated with an organic solvent solution of polyurethane and then the fibrous base material obtained is immersed in water or an aqueous solution of an organic solvent that is a non-solvent for polyurethane, so as to achieve wet coagulation of the polyurethane
Implementation Method 2
adding a crosslinking agent thereto, and heating to produce a sheet-like article
Data Source
AI summary
The present invention provides a production method in which a sheet-like article that has high moist heat resistance and has good surface quality and texture can be produced, regardless of the coagulation technique used for the polyurethane, by an environmentally friendly manufacturing process that is designed to cause reaction of a crosslinking agent while maintaining the texture possessed by the material before crosslinking. The production method for sheet-like articles according to the present invention is a sheet-like article production method characterized by impregnating a fibrous base material with water dispersed polyurethane as a binder, coagulating it to provide a sheet, adding a solution or dispersion liquid of a crosslinking agent to the sheet, and then heating it at a temperature of 100°C or more and 200°C or less.