Photocurable Silicone Composition for Surface and Deep Curing
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Solution Overview
Problem
Existing photocurable silicone compositions face challenges with storage stability, surface curability, and deep-part curability due to issues like oxygen inhibition and the need for both UV and heat curing, which can damage substrates and require complex equipment.
Innovation Solution
A photocurable silicone composition comprising organopolysiloxane, organohydrogenpolysiloxane, a photo-radical polymerization initiator, and a platinum-group metal catalyst activated by light, enabling both radical polymerization and addition reactions to achieve rapid curing without heating, ensuring good storability and curability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a photo-cation polymerization method using an onium salt is used, then the composition can be cured by ultraviolet-ray irradiation, but the substrate may be corroded due to acid generation
Solution Approach 1:
The patent extracts and removes the harmful acid generation step from the curing process by replacing photo-cation polymerization with photo-radical polymerization. This eliminates the corrosion problem while maintaining UV curing capability.
Solution Approach 2:
The patent substitutes the photo-cation polymerization mechanism with a photo-radical polymerization mechanism using a radical polymerization initiator. This chemical mechanism substitution eliminates acid generation while preserving UV-induced curing functionality.
2Productivity
If a radical polymerization method is used, then the curing reaction rate is high and curing is achieved in short time, but the curability on the surface contacted with air is considerably deteriorated due to oxygen deactivation
Solution Approach 1:
The patent merges photo-radical polymerization with addition curing by incorporating both a radical polymerization initiator and a platinum catalyst. This combination allows the composition to undergo both curing mechanisms simultaneously, ensuring complete curing including the oxygen-inhibited surface layer.
Solution Approach 2:
The patent creates a composite curing system that integrates two different curing mechanisms (radical polymerization and addition curing) within a single composition formulation. This composite approach leverages the advantages of both mechanisms while compensating for their individual limitations.
3Reliability
If sensitizers are added to improve curability on the surface, then the reactivity is improved, but the storage stability is deteriorated with gradual curing even in cold and dark places
Solution Approach 1:
The patent changes the chemical parameters of the composition by using a platinum catalyst with high activity that enables addition curing without requiring sensitizers. This parameter change maintains surface curability while eliminating the storage stability problems associated with sensitizer additives.
4Reliability
If addition curing is used to improve surface curability, then the surface curing is improved, but both UV curing and heat curing are required which increases device complexity
Solution Approach 1:
The patent creates a multi-functional curing system where a single UV irradiation step simultaneously activates both radical polymerization and addition curing through the use of a platinum catalyst that is activated by UV light. This eliminates the need for separate heat curing equipment.
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 allows for rapid curing within seconds with excellent surface and deep-part curability, eliminating oxygen inhibition and tackiness, while maintaining storage stability and adhesion strength.
Implementation Method 1
a photo-radical polymerization initiator; (C) a photo-radical polymerization initiator
Implementation Method 2
a platinum-group metal catalyst to be activated by light having a wavelength of 200 to 500 nm
Data Source
AI summary
A photocurable silicone composition, containing: (A) an organopolysiloxane having at least one specific structure having a (meth)acryl group in the molecule; (B) an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to a silicon atom in one molecule; (C) a photo-radical polymerization initiator; and (D) a platinum-group metal catalyst to be activated by light having a wavelength of 200 to 500 nm. The photocurable silicone composition has good storability, and good surface curability and deep-part curability in the air; an adhesive consisting of this photocurable silicone composition; and a cured material of this photocurable silicone composition.