Fluoropolymer Coatings with Fluorinated Additives for Adhesion
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Solution Overview
Problem
Current fluoropolymer compositions face challenges in achieving high crosslinking density and stability, particularly in coatings, due to limitations in cure site reactivity and solvent compatibility, leading to issues with adhesion and durability on various substrates.
Innovation Solution
A composition comprising a fluoropolymer derived predominantly from tetrafluoroethene and unsaturated perfluorinated alkyl ethers, combined with a fluorinated additive containing a silane or (meth)acrylate group, which is cured using a method involving heat or actinic radiation, ensuring crosslinking and solvent removal without solubility in the fluorinated solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fluoropolymer compositions are used, then processing is simplified, but crosslinking density and stability are insufficient
Solution Approach 1:
The patent employs a composite curing system combining multiple cure sites (nitrile groups, iodine, bromine) with different curing mechanisms. This multi-component approach enables high crosslinking density and stability by utilizing synergistic effects of different curing pathways, resolving the contradiction between reliability and complexity.
Solution Approach 2:
The patent modifies the fluoropolymer composition by incorporating specific amounts of cure-site containing monomers (0.1-10 mole percent) and fluorinated additives with controlled molecular weights (≤50,000 g/mole). These parameter changes enable optimized crosslinking density while maintaining processability.
2Strength
If high crosslinking density is achieved, then adhesion and durability improve, but cure site reactivity becomes limited
Solution Approach 1:
The patent introduces fluorinated additives with specific functional groups (silane, (meth)acrylate) at controlled concentrations (0.01-10 wt%) to create localized high-reactivity zones within the polymer matrix. This enables enhanced adhesion strength through targeted crosslinking while maintaining overall composition stability.
3Ease of operation
If fluorinated additives with low molecular weight are used, then viscosity decreases for easy application, but adhesion and crosslinking efficiency may be compromised
Solution Approach 1:
The patent specifies a controlled molecular weight range for fluorinated additives (≤50,000 g/mole) which optimizes the balance between viscosity reduction for easy application and maintenance of crosslinking efficiency. This parameter control ensures low-viscosity coatings that still achieve high crosslinking density.
4Reliability
If cure sites are incorporated into fluoropolymer, then crosslinking is enabled, but solubility in fluorinated solvent is reduced
Solution Approach 1:
The patent incorporates cure sites at controlled concentrations (0.1-10 mole percent of monomer units) to create localized crosslinking regions while maintaining overall polymer solubility in fluorinated solvents. This enables the coating to remain processable as a solution before curing, then develop crosslinking stability after application.
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 solution provides a durable, hydrophobic, and oleophobic coating with enhanced adhesion to substrates, as evidenced by improved contact angles and resistance to abrasion and boiling water tests, while maintaining low viscosity for easy application.
Implementation Method 1
curing the fluoropolymer by exposure to actinic radiation
Implementation Method 2
provides a durable, hydrophobic, and oleophobic coating
Data Source
AI summary
A composition is described comprising at least one fluoropolymer. The fluoropolymer comprises at least 90 % by weight based on the total weight of the fluoropolymer of polymerized units derived from perfluorinated monomers selected from tetrafluoroethene (TFE) and one or more unsaturated perfluorinated alkyl ethers and a fluorinated additive having a Mw of no greater than 50,000 g/mole comprising a partially fluorinated or perfluorinated alkyl or ether group. In some embodiments, the composition further comprises a fluorinated solvent. Also described are substrates comprising a coated surface of the fluoropolymer composition described herein.