Solvent-Free Silicone Elastomer Curing via Radical-Iodonium Synergy
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Solution Overview
Problem
Existing curable compositions for silicones and (meth)acrylate materials often require common solvents, which can limit their application and performance in terms of adhesion, mechanical strength, and optical clarity.
Innovation Solution
A curable composition comprising a mixture of silanol, free radical initiator, and iodonium salt, optionally including alkoxysilane, MQ resin, and (meth)acrylate monomers, which can be cured without common solvents, resulting in pressure-sensitive adhesives or materials with improved optical and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If common solvents are used in curable compositions, then the composition is easier to handle and apply, but the adhesion, mechanical strength, and optical clarity are limited
Solution Approach 1:
The patent removes common solvents from the curable composition formulation. By extracting the solvent component entirely and replacing it with a solvent-free system comprising silanol, free radical initiator, and iodonium salt, the invention eliminates the trade-off between ease of handling and performance. The solvent-free composition achieves both good applicability and superior adhesion, mechanical strength, and optical clarity simultaneously.
Solution Approach 2:
The invention uses a composite curing system combining free radical initiators and iodonium salts with silanol and (meth)acrylate monomers. This composite material approach creates a multi-functional formulation that provides both ease of operation and superior mechanical properties without requiring common solvents, resolving the contradiction between handling ease and performance.
2Ease of operation
If common solvents are used in curable compositions, then the composition is easier to apply, but the optical clarity is limited
Solution Approach 1:
The patent extracts and eliminates common solvents from the formulation. By removing these solvent components that typically compromise optical clarity, the invention achieves superior transparency and optical properties while maintaining ease of application through the solvent-free curable composition system.
3Productivity
If free radical initiator and iodonium salt are used together, then the cure efficiency and gel content are improved, but the composition complexity increases
Solution Approach 1:
The patent merges two different curing mechanisms (free radical and cationic) into a single unified composition system. By combining free radical initiators and iodonium salts in one formulation that cures silanol and (meth)acrylate monomers simultaneously, the invention achieves high cure efficiency and gel content without proportionally increasing complexity, as both initiators work synergistically in the same curable composition.
Solution Approach 2:
The curable composition serves multiple functions simultaneously: it acts as both a free radical polymerization system and a cationic polymerization system, curing both silanol and (meth)acrylate monomers in one process. This multi-functionality improves productivity without requiring separate curing steps or significantly increasing operational complexity.
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 described curable compositions achieve high gel content, excellent peel adhesion, shear strength, and optical clarity, making them suitable for applications such as pressure-sensitive adhesives, gaskets, and optical films, while eliminating the need for common solvents.
Implementation Method 1
b) a free radical initiator; The free radical initiator may be one or more photoinitiators, one or more thermal initiators, or combinations thereof
Implementation Method 2
c) an iodonium salt; Crivello, J. V., 'Cationic Polymerization—Iodonium and Sulfonium Salt Photoinitiators'
Implementation Method 3
a) a silanol; a silanol-terminated polysiloxane
Data Source
AI summary
Curable compositions of this disclosure comprise a mixture of: a silanol, a free radical initiator, an iodonium salt; and optionally an alkoxysilane, and/or an MQ resin, and/or (meth)acrylate monomer(s). In another aspect, cured compositions of this disclosure comprise: a cured silicone, a free radical initiator or residue thereof, an iodonium salt or residue thereof; and optionally a poly(meth)acrylate and/or an MQ resin, which may comprise the cured silicone. In another aspect, cured compositions of this disclosure comprise: a continuous phase of cured silicone, a discontinuous phase of poly(meth)acrylate inclusions, and optionally an MQ resin, which may comprise the cured silicone. The poly(meth)acrylate inclusions may have an average diameter of less than 1.0 micrometer or smaller. The compositions may be pressure sensitive adhesives. The curable and cured compositions may be solvent-free.