Peroxide-Curable Fluoropolymer Composition with Low Viscosity
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Solution Overview
Problem
The challenge lies in developing a curable composition of amorphous peroxide-curable fluoropolymers that maintain low viscosity and enable curing without solvent removal, as high fluoropolymer content solutions are difficult to formulate due to increased viscosity and limited solubility, and typical solvents interfere with the curing process.
Innovation Solution
A curable composition comprising an amorphous peroxide-curable fluoropolymer with a specific solubility parameter range, a solvent with a compatible solubility parameter, and a peroxide, where the fluoropolymer is present from 60% to 97.5% by weight, and the solvent from 1% to 39% by weight, allowing for curing without prior solvent removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high fluoropolymer content is used in the composition, then the mechanical properties and heat resistance are improved, but the viscosity increases making the composition difficult to formulate
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating specific amounts of hexafluoropropylene (5-30 mol%) and perfluoromethyl vinyl ether (10-40 mol%) into the vinylidene fluoride polymer structure. This compositional modification reduces the polymer's inherent viscosity while preserving its mechanical properties and heat resistance, allowing high fluoropolymer content (60-97.5 wt%) to be achieved without excessive viscosity increase.
2Ease of manufacture
If typical solvents are used to reduce viscosity, then the composition becomes easier to handle, but the solvents interfere with the peroxide curing process
Solution Approach 1:
The patent extracts and eliminates the harmful interaction between typical solvents and peroxide curing by using a solvent-free formulation. The modified fluoropolymer composition achieves sufficiently low viscosity through its unique molecular structure and composition, allowing direct peroxide curing without solvent removal steps, thus preventing solvent interference with the curing process.
Solution Approach 2:
The patent introduces a specific polymer composition acting as an intermediary that mediates between the need for low viscosity and effective curing. The modified fluoropolymer with controlled molecular weight and specific comonomer content serves as a bridge, providing processability without requiring traditional solvents that would interfere with peroxide curing.
3Reliability
If solvent removal is performed before curing, then the curing process is improved, but the manufacturing time and complexity increase
Solution Approach 1:
The patent merges the formulation design with the curing process by creating a composition that requires no separate solvent removal step. The modified fluoropolymer's inherent low viscosity allows the composition to be applied and then directly cured with peroxide in a single continuous process, combining what would traditionally be separate steps into one integrated manufacturing process.
4Reliability
If high fluoropolymer content is used, then the chemical resistance is improved, but the solubility in common solvents decreases
Solution Approach 1:
The patent creates a composite polymer structure by copolymerizing vinylidene fluoride with hexafluoropropylene and perfluoromethyl vinyl ether. This composite fluoropolymer structure maintains high chemical resistance from the fluorinated backbone while the specific comonomer ratios and molecular weight control the solubility and viscosity characteristics, enabling high fluoropolymer content formulations with manageable processing properties.
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 achieves unexpectedly low viscosity and effective curing, even with high fluoropolymer content, and exhibits good shelf stability and curing properties, eliminating the need for solvent removal before curing.
Implementation Method 1
Peroxides have been used to crosslink polymers to make cured fluoroelastomers. Peroxide-curable fluoropolymers typically have bromine or iodine cure sites or end groups.
Implementation Method 2
The curable compositions have at least one of the following unexpected properties: (1) an unexpectedly low viscosity in view of the high weight percentage of amorphous peroxide-curable fluoropolymer in the composition
Data Source
AI summary
A curable composition that includes an amorphous, peroxide-curable fluoropolymer having a first solubility parameter, a solvent having a second solubility parameter, and a peroxide. The amorphous, peroxide-curable fluoropolymer is present from 60 percent to 97.5 percent by weight versus the weight of the curable composition, and the solvent is present from 1 percent to 39 percent by weight versus the weight of the curable composition. The absolute value of the first solubility parameter minus the second solubility parameter is less than or equal to 8.2 (MPa)1/2. The solvent may have a solubility parameter in a range from 9.6 (MPa)1/2 to 26 (MPa)1/2. Methods of making a cured fluoroelastomer from the curable composition are also disclosed.