Organopolysiloxane Synthesis via Cyclic Siloxane Segmentation
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Solution Overview
Problem
Existing methods for preparing organopolysiloxanes face challenges in producing polysiloxanes with desired structures, such as sufficiently long linear structures and specific connections between siloxane units, and in maintaining functional groups like alkoxy and hydroxyl groups during the synthesis process.
Innovation Solution
A method involving a specific average composition formula for organopolysiloxane synthesis, which includes a mixture of monofunctional, bifunctional, and trifunctional siloxane units, allowing for a partially-crosslinked structure and direct connection between silicon atoms via oxygen, using a cyclic siloxane compound and an organopolysiloxane with a cage structure, along with a catalyst and controlled reaction conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dehydrating and condensing organosilane or organosiloxane is used to prepare organopolysiloxane, then the organopolysiloxane can be prepared through hydrolysis and condensation, but it is difficult to effectively prepare an organopolysiloxane having a desired structure including sufficiently-long linear structure and direct connection between silicon atoms in bifunctional and trifunctional siloxane units
Solution Approach 1:
The invention uses cyclic siloxane compounds (D4, D5, D6) as segmented building blocks that can be precisely controlled in terms of ring size and composition. By selecting specific cyclic siloxanes and controlling their copolymerization, the patent achieves precise structural control over the linear segments and crosslinking density in the final organopolysiloxane network, resolving the contradiction between structure precision and manufacturing ease.
Solution Approach 2:
The invention changes key parameters including the molar ratios of different cyclic siloxanes (D4:D5:D6), the type of crosslinking agent used, and the catalyst system. By adjusting these parameters, the patent can tune the degree of crosslinking, molecular weight distribution, and linear structure length to achieve desired structural characteristics while maintaining a relatively simple one-step copolymerization process.
2Quantity of substance
If dehydrating and condensing method is used, then organopolysiloxane can be synthesized, but functional groups such as alkoxy groups and hydroxyl groups involved in hydrolysis and condensation are difficult to remain in the prepared organopolysiloxane
Solution Approach 1:
The invention introduces hydrolysable functional groups (alkoxy or halogen atoms) onto the cyclic siloxane monomers before polymerization. These pre-installed functional groups survive the copolymerization process and remain in the final product, providing reactive sites for subsequent modifications while maintaining the simplicity of the one-step synthesis approach.
Solution Approach 2:
The patent uses siloxane bonds as intermediaries that connect the cyclic siloxane units while preserving the alkoxy or halogen functional groups attached to silicon atoms. This intermediary approach allows the functional groups to remain intact during polymerization, enabling both simple synthesis and retention of reactive functionality.
3Reliability
If conventional methods are used to prepare organopolysiloxane, then the synthesis process can be completed, but the prepared organopolysiloxane has insufficient processibility, light extraction efficiency, crack resistance, hardness, and viscosity control
Solution Approach 1:
The invention creates a composite structure by copolymerizing different cyclic siloxanes (D4, D5, D6) with distinct properties. D4 units provide flexibility and processibility, while D5 and D6 units contribute to crosslinking density, hardness, and crack resistance. This composite approach at the molecular level achieves multiple performance requirements simultaneously through a single copolymerization process.
Solution Approach 2:
The patent introduces crosslinking agents with specific local structures that create localized crosslinked regions within the polysiloxane matrix. By controlling the amount and type of crosslinking agent, the invention achieves local reinforcement for improved crack resistance and hardness while maintaining overall processibility and appropriate viscosity of the bulk material.
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
This method enables the production of organopolysiloxanes with excellent processibility, light extraction efficiency, crack resistance, hardness, and viscosity, maintaining suitable physical properties and minimizing functional groups, thus providing a stable and reliable encapsulant for semiconductor devices.
Implementation Method 1
the mixture further comprises a base catalyst
Implementation Method 2
wherein the organopolysiloxane comprises a unit in which a silicon atom of a D unit and a silicon atom of a T unit in a siloxane unit forming the organopolysiloxane are directly bound to each other via an oxygen atom
Data Source
AI summary
Provided is an organopolysiloxane and its use. The organopolysiloxane may exhibit excellent processibility and workability. In addition, when the organopolysiloxane is used as an encapsulant, it exhibits excellent light extraction efficiency, crack resistance, hardness, thermal and shock resistance and an adhesive property. Moreover, the organopolysiloxane may provide an encapsulant exhibiting stable durability and reliability under severe conditions for a long time and having no whitening and surface stickiness