Core-Shell Yarn Coating for Anti-Wicking Aramid Fabrics
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Solution Overview
Problem
Existing water-repellent yarns and fabrics treated with fluoropolymers do not effectively inhibit wicking, and these materials are environmentally undesirable and potentially prohibited, necessitating the development of alternative solutions.
Innovation Solution
The use of core-shell particles with a copolymer shell comprising vinyl aromatic and maleimide monomers, specifically poly(styrene-co-maleimide), is employed to create a super hydrophobic surface on yarns and fabrics, inhibiting water wicking by reducing contact areas and increasing contact angles, thereby preventing vertical water displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluoropolymer treatment is applied to achieve water-repellent properties, then hydrophobicity is improved, but anti-wicking properties are not achieved and environmental harm increases
Solution Approach 1:
The patent changes the chemical composition parameters by replacing fluoropolymer with poly(styrene-co-maleimide) copolymer, and adjusts particle size parameters to 10-300 nm with specific standard deviation, achieving both water-repellent and anti-wicking properties without environmental harm
Solution Approach 2:
The invention uses composite core-shell particles combining hydrophobic core material with poly(styrene-co-maleimide) shell, creating a material that provides both water-repellent and anti-wicking properties while being environmentally friendly
2Manufacturing precision
If core-shell particles with narrow size distribution are used, then manufacturing precision is improved, but anti-wicking performance deteriorates
Solution Approach 1:
The patent identifies and controls the critical parameter of particle size distribution by specifying a standard deviation of at least 10% of the mean value, which creates optimal surface irregularity for anti-wicking while maintaining manufacturing feasibility
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 core-shell particle treatment significantly enhances hydrophobicity and anti-wicking properties, outperforming fluoropolymer treatments by achieving contact angles greater than 90° and virtually eliminating vertical water displacement through the fabric, even in aramid fibers known for strong capillary action.
Implementation Method 1
the shell of the core-shell particle comprises a copolymer of vinyl aromatic monomer and maleimide monomer with a glass transition temperature Tg of between 120 and 220 °C for coating a yarn or fabric to inhibit or prevent wicking
Implementation Method 2
The hydrophobic core-shell particles of the invention cause liquids such as water to have very large contact angles (>90°)
Implementation Method 3
A material covered with very small particles to render an irregular surface, reduces contact areas between liquid and surface. It was now found that in the presence of hydrophobic compounds (e.g. core wax nanoparticles) this results in a super hydrophobic surface where water tends to roll off at only small tilt angles (10-20°)
Implementation Method 4
Virtually no vertical displacement of water (wicking) could be observed through the yarn bundle for 6 hours. This is exceptionally good for aramid fiber with strong capillary working
Data Source
AI summary
The invention relates to the use of core-shell particles with a mean diameter of 10-300 nm and a standard deviation s of at least 10% of the mean value, and wherein the shell of the core-shell particle comprises a copolymer of vinyl aromatic monomer and maleimide monomer with a glass transition temperature Tg of between 120 and 220 °C for coating a yarn or fabric to inhibit or prevent wicking in said yarn or fabric. The invention further relates to an aramid fabric, such as boat sails, which yarns are provided with a finish comprising a diglycehde or a triglyceride obtained from glycerol that is esterified with saturated or unsaturated fatty acids with 6-20 carbon atoms and are then provided with the core-shell particles.