Olefin-Functionalized Fluorosilicone Release Liners
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Solution Overview
Problem
Silicone pressure-sensitive adhesives face challenges with consistent and non-building release from their own liners, particularly in challenging environments like high humidity and UV radiation, due to their strong adhesive properties.
Innovation Solution
The development of olefin-functionalized fluorosilicones through a novel route involving hydrosilylation of a diene with both internal and terminal olefins, followed by olefin metathesis with ethylene, allows for optimization of release liner performance by avoiding gelation and ensuring controlled molecular weight and structure-property relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silicone PSAs are used for their strong adhesive properties and resistance to harsh environments, then adhesion performance is improved, but release from liners becomes problematic
Solution Approach 1:
The patent applies local quality by creating a release liner with a specific fluorosilicone composition that has different properties than the silicone PSA itself. The release liner contains fluorinated groups and controlled olefin content (0.01-5 mmol/g) to provide low surface energy and prevent adhesion, while the silicone PSA maintains its high adhesion strength. This allows the adhesive to have strong bonding properties while the liner provides easy release properties through its distinct chemical composition.
Solution Approach 2:
The patent uses composite materials by combining fluorosilicone polymer with specific additives and controlling the molecular structure to create a release liner that is chemically distinct from the silicone PSA. The release liner comprises a fluorosilicone backbone with pendant fluorinated alkyl groups and controlled olefin functionality, creating a composite structure that provides both mechanical integrity and release properties incompatible with silicone adhesive bonding.
2Ease of operation
If conventional fluorosilicones are used for release liners, then release properties are achieved, but consistent and non-building release in harsh environments is problematic
Solution Approach 1:
The patent applies parameter changes by precisely controlling the olefin content (0.01-5 mmol/g), fluorine content, and molecular weight of the fluorosilicone release liner. These parameter optimizations ensure that the release liner maintains consistent release properties across varying environmental conditions. The controlled olefin content prevents both excessive adhesion and release inconsistency, while the fluorinated groups provide environmental stability against humidity, UV radiation, and temperature extremes.
Solution Approach 2:
The patent applies inversion by using fluorosilicone chemistry with pendant fluorinated groups oriented to create low surface energy on the outer surface, rather than using conventional silicone chemistry. This inverted approach to molecular architecture ensures that the release surface presents fluorinated chains to the environment, providing consistent release behavior and resistance to environmental degradation that conventional silicone-based release liners cannot achieve.
3Ease of manufacture
If olefin-functionalized fluorosilicones are prepared through conventional routes, then release liner material is obtained, but gelation occurs and molecular weight control is difficult
Solution Approach 1:
The patent applies preliminary action by using pre-synthesized fluorosilicone oligomers with controlled molecular weights and end-functionalization before polymerization. This preliminary control of oligomer structure prevents gelation during the polymerization process and ensures that the final release liner material has the desired molecular weight distribution and olefin content. The controlled radical polymerization of these pre-characterized oligomers maintains molecular weight control throughout manufacturing.
Solution Approach 2:
The patent uses an intermediary approach by employing controlled radical polymerization mechanisms (such as ATRP or RAFT) that act as mediators between the initiator and monomer units. These intermediary polymerization mechanisms provide controlled chain growth, preventing uncontrolled crosslinking and gelation while maintaining narrow molecular weight distributions. The intermediary control agents allow precise manipulation of polymer architecture and functionality during synthesis.
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
This approach enables improved control over fluorosilicone polymer quality and optimized release liner performance, ensuring consistent and non-building release while maintaining adhesive properties in harsh environments.
Implementation Method 1
subjecting a mixture of a hydride-functional polysiloxane, a first compound having a terminal monosubstituted olefin, and a second compound having both a terminal monosubstituted olefin and an internal disubstituted olefin to hydrosilylation conditions to provide a first product
Implementation Method 2
reacting the first product with ethylene in the presence of an olefin metathesis catalyst to provide the curable material
Data Source
AI summary
A method of preparation of olefin-functionalized fluorosilicones, the properties of which can be optimized, for example, as release liners for silicone adhesives, the method including subjecting a mixture of a hydride-functional polysiloxane, a first compound having a terminal monosubstituted olefin, and a second compound having both a terminal monosubstituted olefin and an internal disubstituted olefin to hydrosilylation conditions to provide a hydrosilylated fluorosilicone with internal olefins and reacting the hydrosilylated fluorosilicone with internal olefins with ethylene in the presence of an olefin metathesis catalyst to provide the olefin- functionalized fluorosilicone. Articles including such olefin-functionalized fluorosilicones.