Silicone Release Coating Low-Temperature Cure
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Solution Overview
Problem
Current silicone compositions for release papers or films face challenges in achieving both high curability and light release force, particularly on substrates with poor heat resistance, such as plastic films and composite paper substrates, where high temperature curing is limited and there is a need for improved dimensional stability and transparency.
Innovation Solution
A silicone composition comprising an organopolysiloxane with alkenyl groups, a lower molecular weight organopolysiloxane, an organohydrogenpolysiloxane, and a platinum catalyst, specifically formulated to provide good cure properties and non-migratory, low release force coatings without adverse effects on residual bonding force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature curing is used to improve curability of silicone composition, then cure rate is improved, but substrate deformation and appearance degradation occur due to poor heat resistance of plastic film and composite substrates
Solution Approach 1:
The patent changes the chemical parameters of the silicone composition by incorporating specific functional groups (vinyl, phenyl, branched structures) that enable effective crosslinking at lower curing temperatures, thus achieving good curability without subjecting heat-sensitive substrates to high temperatures that cause deformation
Solution Approach 2:
The patent uses a composite approach by combining multiple components in the silicone composition including organopolysiloxane with vinyl groups, organohydrogenpolysiloxane, and crosslinking agents, creating a multi-component system that achieves enhanced curability at reduced temperatures while maintaining substrate integrity
2Reliability
If conventional silicone composition is used to achieve adequate cure, then curability is maintained, but release force is excessively high and mold parting function is insufficient
Solution Approach 1:
The patent applies local quality by creating a cured coating with specific local characteristics - the surface layer possesses low release force properties through controlled crosslinking density and functional group distribution, while the bulk maintains adequate cure and structural integrity, enabling effective mold parting without compromising overall coating performance
Solution Approach 2:
The patent modifies the chemical composition parameters by incorporating specific ratios of vinyl-containing polysiloxane, phenyl-containing polysiloxane, and crosslinking agents, along with controlling molecular weight distribution and branching, to achieve the optimal balance between cure adequacy and reduced release force for improved mold parting
3Reliability
If branched structure containing RSiO 3/2 units is incorporated to improve cure, then curability is improved, but release force increases upon high-speed peeling
Solution Approach 1:
The patent precisely controls the concentration and type of branched structures (RSiO 3/2 units) within specific ranges, combining them with vinyl and phenyl functional groups in optimized ratios, to achieve sufficient crosslinking for good curability while preventing excessive release force that would occur with higher concentrations of branched structures alone
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 enables the formation of coatings with excellent curability, non-migratory properties, and light release force, suitable for various pressure-sensitive adhesives, while maintaining satisfactory residual adhesion and preventing deformation under heat, thus addressing the limitations of prior art.
Implementation Method 1
silicone compositions of addition reaction type adapted to cure via hydrosilylation reaction are well known, for example, a silicone composition comprising an alkenyl-containing organopolysiloxane, an organohydrogenpolysiloxane, and a platinum base compound
Implementation Method 2
coating a curable silicone composition as silicone-base release agent to the surface of substrates such as plastic film or paper, and effecting crosslinking reaction to form a cured coating
Data Source
AI summary
Provided are: an additive reaction-type silicone composition that is for release paper or for a release film, that is non-migratory, and that exhibits light releasability with respect to various adhesives, said silicone composition for release paper or for a release film making it possible to form a cured film that does not adversely affect residual adhesive strength or releasability; and a release paper or a release film obtained by applying the composition to a substrate and curing the result. In a silicone composition for release paper or a release film cured by additive reaction, an organopolysiloxane containing an alkenyl group having a terminal unsaturated bond is used as a base polymer, and a specific amount of an organopolysiloxane that has a lower molecular weight than the base polymer and that contains an alkenyl group having a terminal unsaturated bond is mixed with the base polymer.