Short-Chain Fluoropolymer Coating for Air-Dried Oil Repellency
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Solution Overview
Problem
Existing water/oil repellent compositions that use copolymers with polyfluoroalkyl groups of 7 or more carbon atoms pose environmental concerns due to their persistence and accumulation, while compositions limiting the carbon chain length to 6 or less in the monomers result in insufficient post-air-drying water/oil repellency.
Innovation Solution
A water/oil repellent composition comprising a copolymer with specific monomer units, including a C4-6 polyfluoroalkyl group, vinylidene chloride, and crosslinkable functional groups, combined with film-forming assistants, to achieve sufficient post-air-drying water/oil repellency while minimizing environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a copolymer with polyfluoroalkyl groups of 7 or more carbon atoms is used, then water/oil repellency is improved, but environmental impact worsens due to persistence and accumulation
Solution Approach 1:
The patent changes the parameter of polyfluoroalkyl group length from 7 or more carbon atoms to 6 or fewer carbon atoms. This parameter modification maintains the water/oil repellency function while reducing environmental persistence and accumulation, thereby resolving the contradiction between performance and environmental impact
Solution Approach 2:
The patent uses a composite copolymer structure containing multiple functional units: polyfluoroalkyl groups for repellency, carboxylic acid groups for metal coordination, and units with glass transition temperatures of 50°C or lower for film formation. This composite structure enables short-chain polyfluoroalkyl groups to achieve performance comparable to long-chain groups while maintaining environmental benefits
2Object-affected harmful factors
If the carbon chain length of polyfluoroalkyl groups is limited to 6 or less, then environmental impact is reduced, but post-air-drying water/oil repellency becomes insufficient
Solution Approach 1:
The patent creates a composite copolymer containing four types of structural units: (I) polyfluoroalkyl groups (C1-6) for repellency, (II) carboxylic acid groups for metal coordination and film formation, (III) units with glass transition temperature ≤50°C for flexible film formation during air-drying, and (IV) hydrophilic groups for water resistance. This composite structure enables short-chain polyfluoroalkyl groups to achieve sufficient post-air-drying repellency through synergistic interactions
Solution Approach 2:
The patent introduces carboxylic acid groups as intermediary units that can coordinate with metal ions and interact with both the polyfluoroalkyl groups and the matrix polymer. These intermediary units facilitate the formation of a cohesive film during air-drying that maintains the repellency function of the short-chain polyfluoroalkyl groups, resolving the insufficiency of post-air-drying performance
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 imparts effective post-air-drying water/oil repellency to articles while reducing environmental concerns by avoiding the use of perfluoroalkyl groups with 7 or more carbon atoms, ensuring both performance and sustainability.
Implementation Method 1
the aqueous medium (B) contains water and at least one film-forming assistant selected from the following film-forming assistant (x) and the following film-forming assistant (y)
Implementation Method 2
a copolymer (A) having (I) structural units based on a monomer having a polyfluoroalkyl group
Data Source
AI summary
To provide a water/oil repellent composition which can impart sufficient post-air-drying water/oil repellency to the surface of an article, and which presents a low environmental impact, and an article having its surface treated with the water/oil repellent composition. A water/oil repellent composition comprising a copolymer (A) having structural units based on a monomer (a), structural units based on a monomer (b), structural units based on a monomer (c) and/or structural units based on a monomer (d); and an aqueous medium (B) containing water, and a film-forming assistant (x) and/or a film-forming assistant (y). Monomer (a): a monomer having a C1-6 polyfluoroalkyl group, monomer (b): vinylidene chloride, monomer (c): a monomer, the homopolymer of which has a glass transition temperature of at least 20° C., monomer (d): a monomer having a crosslinkable functional group, film-forming assistant (x): a specific amide solvent, and film-forming assistant (y): a specific glycol solvent.