Radiation-Curable Silicone Composition for Oxygen-Tolerant Adhesion
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Solution Overview
Problem
Existing radiation-curable silicone compositions for release sheets face challenges in achieving improved adhesion to substrates while maintaining release properties, with previous compositions either having reduced adhesion or requiring specific conditions to avoid oxygen inhibition.
Innovation Solution
A radiation-curable silicone composition comprising an alkenyl-containing organopolysiloxane, a mercaptoalkyl-containing organopolysiloxane, a silane compound with multiple acrylic groups, and a radical polymerization initiator, which enhances adhesion without compromising release properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thiol-ene reaction of mercapto-modified polyorganosiloxane is used for radiation curing, then cure can proceed without oxygen inhibition, but the reaction rate is slower than acrylic radical polymerization, leading to lower adhesion to substrates
Solution Approach 1:
The patent combines two different curing mechanisms: acrylic radical polymerization (fast reaction rate, high adhesion) and thiol-ene reaction (oxygen-insensitive). The composition includes both acrylic-modified polysiloxane and mercapto-modified polysiloxane, allowing both reactions to occur simultaneously during radiation curing, thus achieving both fast adhesion and oxygen-insensitive curing
Solution Approach 2:
The patent creates a composite curing system using multiple polysiloxane components with different functional groups (acrylic and mercapto). This composite approach allows the material to exhibit properties of both individual systems: the rapid adhesion bonding of acrylic polymerization and the oxygen tolerance of thiol-ene reaction
2Strength
If acrylic modified polysiloxane is used for radical polymerization, then the film is tightly adhesive to substrates and effectively curable, but a device for reducing oxygen concentration is necessary because cure is inhibited by oxygen
Solution Approach 1:
The mercapto-modified polysiloxane acts as an intermediary component that enables oxygen-tolerant curing. The thiol groups in this component can undergo radical reactions even in the presence of oxygen, effectively mediating the curing process when oxygen would normally inhibit the acrylic polymerization
Solution Approach 2:
The patent changes the chemical parameters of the polysiloxane composition by incorporating mercapto-functional groups alongside acrylic groups. This parameter change allows the system to tolerate oxygen presence while maintaining effective curing and adhesion
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 improved adhesion to substrates while maintaining release properties, even in the presence of oxygen, and is curable under various conditions, enhancing its applicability and market expansion.
Implementation Method 1
radical polymerization of acrylic modified polysiloxane using a photo-radical initiator
Implementation Method 2
thiol-ene reaction of mercapto-modified polyorganosiloxane using a photo-radical initiator
Data Source
AI summary
Provided are: a radiation-curable silicone release composition which has excellent radiation curability and gives cured objects having excellent adhesiveness to the substrates; and a release sheet. The radiation-curable silicone release composition comprises the following components (A), (B), (C), and (D): (A) 100 parts by mass of an organopolysiloxane having an alkenyl group; (B) 1-30 parts by mass of an organopolysiloxane having a mercaptoalkyl group; (C) 0.1-5 parts by mass of a compound having a plurality of acryl groups in the molecule; and (D) 0.1-15 parts by mass of a photopolymerization initiator.