Fluoropolymer Curing with Electron Donor Groups for High Crosslinking Density

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Solution Overview

Problem

Existing methods for making crosslinked fluoropolymers lack efficiency in achieving high crosslinking density and stability, particularly when using UV radiation for curing.

Innovation Solution

A method involving the application of a composition containing fluoropolymer, fluorinated solvent, and curing agents with ethylenically unsaturated groups and electron donor groups, followed by solvent removal and UV radiation curing to achieve crosslinking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional methods are used to make crosslinked fluoropolymers, then the process is simpler, but the crosslinking density and stability are insufficient

Engineering Contradiction:

Improvecrosslinking stabilityVSAvoidcuring process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces specific chemical parameters (electron donor groups with specific electron donation capabilities, ethylenically unsaturated groups with specific reactivity) to transform the curing process. By changing the chemical nature of the curing agent and its interaction parameters with the fluoropolymer, the crosslinking density and stability are significantly improved while maintaining a manageable process complexity through controlled chemical reactions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite curing system combining electron donor groups, ethylenically unsaturated groups, and fluoropolymer matrices. This composite approach allows multiple functional groups to work synergistically, achieving high crosslinking density and stability through the combined effects of different chemical components rather than relying on a single curing mechanism.

Inventive Principle:

Principle #40Composite materials

2Productivity

If UV radiation is used for curing, then the curing speed increases, but the crosslinking density and stability are not sufficiently achieved

Engineering Contradiction:

Improvecuring speedVSAvoidcrosslinking stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent modifies the chemical parameters of the curing system by introducing electron donor groups and ethylenically unsaturated groups that are specifically responsive to UV radiation. These parameter changes enable the curing process to proceed rapidly under UV irradiation while simultaneously achieving high crosslinking density through the enhanced reactivity and bonding capabilities of the introduced functional groups.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces conventional thermal or chemical curing mechanisms with a UV-based photocuring system. This substitution uses optical energy (UV radiation) to initiate and drive the crosslinking reaction, achieving both rapid curing speed and high crosslinking stability through the photochemical activation of the electron donor and unsaturated groups without requiring high temperatures or extended reaction times.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If high crosslinking density is achieved, then the stability improves, but the fluoropolymer loses its ability to dissolve in fluorinated solvent

Engineering Contradiction:

Improvecrosslinking stabilityVSAvoidsolubility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent carefully controls the parameters of the crosslinking reaction by selecting specific electron donor groups and ethylenically unsaturated groups that form crosslinks with controlled density and distribution. This parameter optimization allows achieving sufficient crosslinking stability while maintaining enough chain mobility and free volume to preserve solubility in fluorinated solvents, balancing the contradiction between network rigidity and solvent compatibility.

Inventive Principle:

Principle #35Parameter changes

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 method effectively results in high crosslinking density and stability of the fluoropolymer, as evidenced by the fluoropolymer's inability to dissolve in the fluorinated solvent post-curing.

Implementation Method 1

curing the fluoropolymer with actinic (e.g. ultraviolet "UV") radiation

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

removing the solvent

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS12291588B2Fluoropolymer compositions comprising a curing agent with ethylenically unsaturated and electron donor groups, and substrates coated therewith

Publication Date: 2025.05.06 3M INNOVATIVE PROPERTIES CO

AI summary

A method of making a crosslinked fluoropolymer is described. The method comprises applying a composition to a substrate, wherein the composition comprises fluoropolymer and a fluorinated solvent, one or more curing agents comprising an ethylenically unsaturated group and an electron donor group or precursor thereof. The method further comprises removing the solvent and curing the fluoropolymer with actinic (e.g. ultraviolet “UV”) radiation. Also described is a composition comprising a fluoropolymer dissolved in a fluorinated solvent, and one or more curing agents comprising an ethylenically unsaturated group and an electron donor group or precursor thereof; and article comprising the crosslinked fluoropolymer.