Water/Oil Repellent Copolymer Coating for Low-Infiltration Durability
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Solution Overview
Problem
Existing water/oil repellent compositions that use copolymers with polyfluoroalkyl groups face environmental concerns due to decomposition and infiltration issues, leading to design impairments and high environmental impact.
Innovation Solution
A water/oil repellent composition comprising a copolymer with structural units based on specific monomers, including a C1-6 polyfluoroalkyl group and vinyl chloride, and an aqueous medium, with a mass average molecular weight of at least 60,000, and a zeta potential of 10-40 mV, which suppresses infiltration of coating liquids and enhances washing durability while reducing environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a copolymer with polyfluoroalkyl groups (at least 8 carbon atoms) is used for water/oil repellency, then water/oil repellency is improved, but environmental impact increases due to decomposition and accumulation
Solution Approach 1:
The patent changes the carbon atom parameter of the polyfluoroalkyl group from at least 8 to at most 6 carbon atoms. This parameter modification maintains the water/oil repellency function while reducing environmental persistence and decomposition products, directly resolving the contradiction between effectiveness and environmental safety
Solution Approach 2:
The patent creates a composite copolymer structure combining polyfluoroalkyl groups (for repellency) with vinyl chloride units (for durability and structural stability). This composite approach allows the fluorinated portion to provide protection while the vinyl chloride portion enhances overall performance and reduces environmental impact through controlled degradation
2Reliability
If a coating liquid is applied to form a moisture-permeable waterproofing film, then waterproofing function is improved, but infiltration into the article surface impairs design
Solution Approach 1:
The patent applies the water/oil repellent composition specifically to the surface of the article, creating a localized treatment layer that provides waterproofing functionality without requiring infiltration into the bulk material. This surface-specific application maintains the article's original design and appearance while adding protective functionality
Solution Approach 2:
The patent uses a copolymer composition that forms a surface-level protective layer rather than requiring deep infiltration. This approach creates a functional coating that can be applied as needed without permanently altering the article's structure or design, allowing for flexible application and maintenance
3Ease of manufacture
If a copolymer with lower molecular weight is used for easier processing, then ease of manufacture is improved, but washing durability deteriorates
Solution Approach 1:
The patent optimizes the mass average molecular weight parameter to at least 60,000, finding the optimal balance between processability and performance. This specific molecular weight range ensures sufficient chain entanglement for durability while maintaining adequate solubility and processability, resolving the contradiction between ease of manufacture and washing durability
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 composition provides excellent water/oil repellency and washing durability while preventing infiltration of coating liquids, maintaining design integrity and reducing environmental impact by using a copolymer with a high molecular weight and specific monomer composition.
Implementation Method 1
a water/oil repellent composition composed of an emulsion having, dispersed in an aqueous medium, a copolymer having structural units based on a monomer having a polyfluoroalkyl group
Implementation Method 2
a copolymer having structural units based on a monomer having a polyfluoroalkyl group (a polyfluoroalkyl group will be hereinafter referred to as a Rf group)
Data Source
AI summary
To provide a water/oil repellent composition with which an article which has favorable water/oil repellency and washing durability, and into which infiltration of a coating liquid can be suppressed, is obtained, and which presents a low environmental impact, its production method and an article having its surface treated with the composition. A water/oil repellent composition comprising a copolymer (X) having structural units based on the monomer (a) and structural units based on the monomer (b), and an aqueous medium, wherein the mass average molecular weight of the copolymer is at least 60,000, and the proportion of the structural units based on the monomer (a) is 60 to 95 mass %. Monomer (a): by (Z—Y)nX, wherein Z is a e.g. C1-6 polyfluoroalkyl group, Y is e.g. a bivalent organic group having no fluorine atom, n is 1 or 2, and X is a polymerizable unsaturated group. Monomer (b): vinyl chloride.