Dual-Cure Polyorganosiloxane Composition for Shadow-Area Curing
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Solution Overview
Problem
Existing polyorganosiloxane compositions face challenges in achieving ease of synthesis, low volatile content, rapid curability, and superior optical/physical stability, particularly in coating materials, encapsulants, sealants, and adhesives, while also addressing issues of poor curability and toughness in shadow areas and thermal expansion.
Innovation Solution
A light curable, light-heat or light-moisture dually curable polyorganosiloxane composition is developed, featuring a siloxane-based polymer with regularly distributed (meth)acrylic functional groups, obtained through hydrosilylation reactions, which includes Si-bonded (meth)acryloxy alkyl radicals and alkenyl or hydrogen atoms, combined with a photoinitiator, crosslinking components, and hydrosilylation catalysts, enabling efficient curing and improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If UV-curable silicone systems with mercaptan groups are used, then crosslinking reactivity is improved, but offensive odors persist in the cured products and long-term reliability is insufficient
Solution Approach 1:
The patent replaces persistent mercaptan groups with alternative crosslinking mechanisms that achieve rapid curing without leaving harmful residues. The composition uses vinyl-functional siloxanes and organometallic catalysts that complete the crosslinking reaction fully, eliminating the need for residual mercaptan groups that cause odors and reliability issues.
Solution Approach 2:
The patent changes the chemical parameters of the crosslinking system by using vinyl-functional siloxanes with organometallic catalysts instead of mercaptan-based systems. This parameter change maintains high crosslinking reactivity while eliminating the harmful odor-generating mercaptan groups from the final cured product.
2Speed
If light curable polyorganosiloxane composition is used, then surface region curability is improved, but shadow area curability and hardness are poor
Solution Approach 1:
The patent segments the curing mechanism into two parts: UV-initiated crosslinking for surface areas and moisture-initiated crosslinking for shadow areas. This dual-curing approach ensures that both exposed and protected regions achieve complete curing and appropriate hardness.
Solution Approach 2:
The composition is designed with multi-functionality to cure through multiple mechanisms. The vinyl-functional siloxane composition can undergo both UV-photo crosslinking and moisture-cure crosslinking, making it universally applicable to both light-exposed and shadow areas.
3Stability of the object's composition
If light-heat dually curable polyorganosiloxane composition is used, then heat resistance and cold resistance are improved, but cracking occurs during curing and coefficient of thermal expansion is high
Solution Approach 1:
The patent eliminates the need for heat curing by using moisture-cure crosslinking instead. This removes the thermal stress that causes cracking while maintaining the desired thermal resistance properties through the silicone backbone structure.
Solution Approach 2:
The patent changes the curing temperature parameter from high-temperature heat cure to ambient-temperature moisture cure. This parameter change eliminates thermal expansion issues and cracking during curing while achieving the desired heat resistance through the chemical structure of the cured silicone network.
4Ease of manufacture
If conventional polyorganosiloxane composition is used, then synthesis simplicity is maintained, but volatile content and curability are high
Solution Approach 1:
The patent changes the molecular structure parameters by using vinyl-functional siloxanes with controlled molecular weights and functionality. This reduces volatile content by eliminating low-molecular-weight components while maintaining synthesis simplicity through straightforward mixing of pre-synthesized vinyl-functional components.
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 exhibits excellent curability, toughness, and optical/physical stability, with the cured body demonstrating quick curing, high adhesion, and resistance to cracking, suitable for various applications including electronic devices.
Implementation Method 1
Ultraviolet radiation (UV) is one of the most widely used types of radiation because of its low cost, ease of maintenance, and low potential hazard to industrial users. Typical curing times are much shorter, and heat-sensitive materials can be safely coated and cured under UV radiation where thermal energy might damage the substrate.
Implementation Method 2
the light curable polyorganosiloxane composition has excellent curability in the surface region directly in contact with UV irradiation, but has poor curability and low hardness in a shadow area
Data Source
AI summary
The present disclosure relates to a light curable, light-heat or light-moisture dually curable, or light-heat-moisture multiple curable polyorganosiloxane composition, which has ease of synthesis, low volatile content, rapid curability, excellent toughness and/or superior optical/physical stability in a variety of fields such as coating materials, encapsulants, sealants and adhesives, a cured body obtained by curing said compositions, and an electronic device comprising the same.