A sheet-like article and a production method thereof
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Solution Overview
Problem
Existing methods for producing sheet-like articles using water-dispersed polyurethane result in stiff textures due to differences in coagulation techniques compared to organic solvent-based methods, lacking the softness and flexibility of products made with organic solvents.
Innovation Solution
A sheet-like article produced using a fibrous base material with ultrafine fibers and a polymer elastomer having a hydrophilic group, where the polymer elastomer forms a crosslinked structure, and the production process involves adding an aqueous resin dispersion liquid with a viscosity improver and coagulating in hot water to create a porous structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water-dispersed polyurethane is used instead of organic solvent-based polyurethane, then environmental harm is reduced, but the texture becomes stiff
Solution Approach 1:
The invention changes the coagulation parameters by controlling temperature (90-100°C) and time (5-30 minutes) to achieve a porous polyurethane structure that maintains softness while using environmentally friendly water-dispersed polyurethane
Solution Approach 2:
The invention creates a porous structure in the polyurethane film through controlled coagulation, which reduces fiber entanglement contact area and prevents stiff texture, while maintaining the environmental benefits of water-based dispersion
2Reliability
If wet heat coagulation technique is used for water-dispersed polyurethane, then coagulation is achieved, but the texture becomes stiff due to high-density nonporous film structure
Solution Approach 1:
The invention modifies the wet heat coagulation parameters by using higher temperatures (90-100°C) and extended times (5-30 minutes) to create a porous structure rather than a dense nonporous structure, achieving both effective coagulation and soft texture
Solution Approach 2:
The invention intentionally creates a porous structure within the polyurethane film during coagulation, which reduces the contact area between fibers and polyurethane, thereby preventing strong entanglement and stiff texture while maintaining coagulation effectiveness
3Ease of operation
If foaming agent is added to create porous structure, then texture softness is improved, but manufacturing complexity increases
Solution Approach 1:
The invention removes the foaming agent from the process, achieving porous structure formation through controlled coagulation parameters alone, thereby simplifying the manufacturing process while maintaining texture softness
Solution Approach 2:
The invention uses temperature and time as intermediaries to control the coagulation process, allowing porous structure formation without adding foaming agents or other complex additives
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 achieves a sheet-like article with fold and crease recoverability and flexibility comparable to those made with organic solvent-based polyurethane, offering a uniform feel and elegant surface quality without the use of organic solvents.
Implementation Method 1
the method involving the coagulation of a polyurethane solution in an organic solvent uses the so-called wet coagulation technique in which polyurethane molecules dissolved in an organic solvent are coagulated by substituting water for solvent
Implementation Method 2
For coagulation of water-dispersed polyurethane, on the other hand, the wet heat coagulation technique is mainly used, in which heating is performed to destroy the hydrated state of the dispersion liquid of water-dispersed polyurethane to cause the aggregation of emulsion particles of polyurethane to achieve coagulation
Implementation Method 3
the production process involves adding an aqueous resin dispersion liquid with a viscosity improver and coagulating in hot water to create a porous structure
Data Source
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AI summary
The invention relates to an environmentally friendly production method for a sheet-like article that does not use an organic solvent in the production process and provides a sheet-like article that compares favorably in terms of a uniform feel with artificial leather products produced from an organic solvent based polyurethane and in particular has good surface quality and texture and also provides a production method therefor. The present invention aims to provide a sheet-like article comprising a fibrous base material formed of ultrafine fibers and/or ultrafine fiber bundles provided with, as a binder, a polymer elastomer having a hydrophilic group, any thickness-directional cross section of the sheet-like article containing regions occupied by the polymer elastomer, the regions including independent regions each with a cross-sectional area of 50 µm2 or more, the total area of the independent regions accounting for 0.1% or more and 5.0% or less of the cross-sectional area of the artificial leather in an observation view field. The production method for the sheet-like article according to the present invention provides a production process for a sheet-like article including a fibrous base material formed of ultrafine fibers and, as a binder, a polymer elastomer having a hydrophilic group, the process including a step for adding an aqueous resin dispersion liquid containing a water-dispersed polymer elastomer and a viscosity improver to a fibrous base material and a step for coagulating the polymer elastomer in hot water at a temperature of 50°C to 100°C.