Fluoroelastomer Cure System for Oxygen Plasma Resistance
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Solution Overview
Problem
There is a need for a curing agent that can quickly cure fluoroelastomers and perfluoroelastomers while maintaining their chemical and plasma resistance properties, particularly without relying on peroxide cure systems, and existing curing agents are either slow or introduce metallic contaminants.
Innovation Solution
A cure system comprising a functionalized biphenyl-based curative and a dioxime compound, along with a monoamidine-based compound, is used to accelerate the curing process of fluoroelastomeric compositions, reducing cure time and ensuring resistance to chemical and thermal degradation, including oxygen plasma resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If peroxide cure systems are used, then cure speed is improved, but thermal stability and chemical resistance deteriorate
Solution Approach 1:
The patent introduces a perfluoropolyether as an intermediary substance that mediates between the peroxide cure system and the fluoroelastomer matrix. This intermediary allows the peroxide to function as a cure accelerator while the perfluoropolyether protects the system from thermal degradation and maintains chemical resistance, thus resolving the contradiction between cure speed and reliability
Solution Approach 2:
The patent creates a composite cure system combining peroxide, perfluoropolyether, and fluoroelastomer components. This composite approach allows the system to benefit from the fast curing of peroxide while the perfluoropolyether provides thermal stability and chemical resistance, simultaneously achieving both improved cure speed and maintained reliability
2Speed
If organometallic curing agents are used, then cure rate is improved, but metallic contaminants are introduced
Solution Approach 1:
The patent replaces permanent metallic curing agents with organic peroxide-based curing agents that decompose completely after curing. The peroxide acts as a temporary catalyst that fulfills its curing function and then breaks down into harmless byproducts, eliminating the persistent contamination issue of metallic agents while maintaining fast cure rates
Solution Approach 2:
The patent changes the chemical nature of the curing agent from metallic (organometallic) to organic (peroxide-based). This parameter change in the curing agent's chemical composition eliminates metallic contamination while the peroxide's decomposition characteristics provide fast cure rates through controlled breakdown into non-toxic products
3Reliability
If functionalized biphenyl-based curatives are used, then chemical resistance is improved, but cure time increases
Solution Approach 1:
The patent merges two curing mechanisms: the functionalized biphenyl-based curative provides chemical resistance through its reaction with the fluoroelastomer, while the peroxide system provides fast curing. The perfluoropolyether acts as a bridge between these two systems, allowing them to work synergistically rather than competitively, thus achieving both long cure time and fast overall cure rate
Solution Approach 2:
The peroxide system performs preliminary curing action quickly to establish initial crosslinks and gel structure, while the functionalized biphenyl curative continues the curing process to achieve final chemical resistance. This preliminary action by the peroxide system reduces the overall cure time while the biphenyl curative ensures final chemical resistance
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 proposed cure system decreases cure time by 30% to 60% and maintains the beneficial properties of fluoroelastomers, such as low sticking and chemical resistance, while avoiding the use of peroxide-based systems and metallic contaminants.
Implementation Method 1
a cure system comprising a functionalized biphenyl-based curative and a dioxime compound, along with a monoamidine-based compound, is used to accelerate the curing process of fluoroelastomeric compositions
Implementation Method 2
ensuring resistance to chemical and thermal degradation, including oxygen plasma resistance
Implementation Method 3
resistance to chemical and thermal degradation
Data Source
AI summary
The invention provides a curable fluoroelastomeric composition comprising: (i) a fluoropolymer comprising at least one cure site monomer that comprises at least one cyano group; (ii) a cure system comprising a functionalized biphenyl-based compound and at least one of: a dioxime compound represented by the formula (I): HON═R1═NOHwherein R1 is chosen from an alkyl group having 1 to 10 carbon atoms and an aryl group having 1 to 10 carbon atoms; a monoamidine-based compound represented by formula (IV):wherein Y is chosen from a substituted or unsubstituted alkyl, aryl, or aralkyl group or an unsubstituted or substituted fully or partially halogenated alkyl, aryl, or aralkyl group having to 22 carbon atoms; R4 is chosen from a hydrogen atom or a substituted or unsubstituted lower alkyl group of 1 to 6 carbon atoms, or an amino group; R5 is independently chosen from hydrogen atom, a substituted or unsubstituted lower alkyl group of 1 to 6 carbon atoms, an amino group or an hydroxyl group; and/or a perfluoropolyether. Also included are additional related compositions and methods.