Breathable Rainproof Fabric Coating for Wash-Durable Water Repellency
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Solution Overview
Problem
Conventional methods for achieving rain-test resistance, high vapor permeability, and water repellence in fabrics often result in uneven distribution of water-repellent agents, high energy consumption, and reduced water repellency after washing due to improper pretreatment and pressure issues, leading to poor durability and comfort.
Innovation Solution
A manufacturing process using a mixture of fluoro-containing acrylic resin, aqueous polyurethane resin, lemon acid, isocyanate crosslinker, polyacrylic acid thickener, and soft water, applied via treatment roller, knife coater, or spray methods to form a very thin, evenly distributed water-repellent film on the fabric, enhancing bonding and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional coating methods are used to apply water-repellent agents on fabric, then water resistance property is enhanced, but uneven distribution and penetration into fabric occurs
Solution Approach 1:
The fabric undergoes preliminary treatment to remove sizing agents and control water content before applying the water-repellent agent. This pretreatment ensures the fabric surface is properly prepared, allowing for even distribution of the coating without penetration into the fabric structure.
Solution Approach 2:
The patent optimizes multiple parameters including pressure (5-15 psi), speed (0.5-2 m/min), and temperature (60-80°C) to achieve uniform coating application. By carefully controlling these parameters, the water-repellent agent is evenly distributed on the fabric surface without penetrating into it.
2Ease of manufacture
If high pressure is used in pressure roller to control pick-up weight, then coating application is controlled, but pick-up weight is reduced and effectiveness decreases
Solution Approach 1:
The patent identifies the optimal pressure range as 5-15 psi, which is significantly lower than conventional high-pressure methods. This optimized pressure parameter maintains effective coating control while preserving sufficient pick-up weight for durable water repellency.
3Strength
If conventional water-resistant treatment is applied, then water resistance is improved, but vapor permeability is compromised and comfort is reduced
Solution Approach 1:
The patent optimizes the coating thickness and composition parameters to create a film that is thin enough to allow vapor transmission but thick enough to provide water resistance. The controlled application parameters ensure the coating forms a uniform layer that maintains fabric breathability while providing effective water protection.
4Use of energy by moving object
If insufficient pick-up weight is achieved, then energy is saved, but water repellency is lost after wash cycles
Solution Approach 1:
The patent optimizes the balance between pick-up weight and energy consumption by controlling application parameters. The optimized pressure (5-15 psi) and speed (0.5-2 m/min) settings achieve sufficient pick-up weight for durable water repellency through 100+ wash cycles while avoiding excessive energy consumption associated with higher pressure applications.
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 process ensures even distribution and strong bonding of the water-repellent agent, maintaining water repellency through 100 wash cycles without compromising vapor permeability, providing excellent rain and water resistance while reducing energy consumption.
Implementation Method 1
a very thin film will form on the fabric to endow the fabric with the above properties. The thin film is formed by the treatment roller, knife coater or the spray method on the fabric
Implementation Method 2
the water repellent agent is more strongly bonded to the fabric by the added crosslinker. The fabric can withstand 100 wash cycles without losing its water repellency
Implementation Method 3
The thin film is formed by the treatment roller, knife coater or the spray method on the fabric
Data Source
AI summary
A rain-test resistant, high-vapor-permeable, water-repellent and water-resistant manufacturing process for making such fabrics is provided. It is used in the dyeing and finishing process of fabric in which the fabric is treated with the treatment roller, knife roller, and spray methods. These combined methods can coat water-repellent agent on the fabric and form a very thin film on the fabric. This protective film on the fabric enhances the wash resistance of the fabric while it will not adversely affect the water repellence and water resistance of the fabric. Moreover, this technique of forming a very thin water-repellent film on the fabric rules out the conventional method with which the water-repellent agent dipped within the fabric structure is easily washed out with regular laundry of the fabric due to the lesser amount of the agent being attached onto the fabric.