Epoxy-Functional Cyclic Organopolysiloxane for Crack-Resistant Curing
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Solution Overview
Problem
Conventional curable epoxy materials are susceptible to crack formation and lack flexibility, which is a drawback in applications requiring durability and resistance to mechanical stress.
Innovation Solution
An epoxy group-containing cyclic organopolysiloxane is developed, where epoxy group-containing cyclic siloxanes are linked through a linking group, enhancing flexibility and crack resistance by polymerization, and a curable composition comprising this organopolysiloxane with a curing agent is used to form a cured product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional curable epoxy materials are used, then heat yellowing resistance and low cure shrinkage are achieved, but crack resistance and flexibility are poor
Solution Approach 1:
The invention uses a composite structure where epoxy group-containing cyclic siloxane units are incorporated into a polysiloxane backbone. This composite material combines the heat resistance of epoxy groups with the flexibility and crack resistance of siloxane backbones, resolving the contradiction between heat yellowing resistance and crack resistance.
Solution Approach 2:
The invention changes the chemical structure parameters by introducing cyclic siloxane units with specific epoxy group placements (positions 2, 3, 4, or 5) and controlling the number of epoxy groups (1-4 per unit). This structural parameter optimization enables the cured product to achieve both heat resistance and improved crack resistance.
2Reliability
If conventional curable epoxy materials are used, then heat yellowing resistance is improved, but flexibility is insufficient
Solution Approach 1:
The polysiloxane backbone with epoxy group-containing cyclic siloxane units creates a composite material that maintains the flexibility characteristic of siloxanes while incorporating the heat resistance of epoxy groups, thus achieving both heat yellowing resistance and flexibility simultaneously.
Solution Approach 2:
By modifying the polysiloxane structure to include cyclic siloxane units with epoxy groups at specific positions and controlling the epoxy group equivalent weight (200-400 g/mol), the invention optimizes the balance between heat resistance and flexibility.
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 cured product exhibits improved crack resistance and flexibility, suitable for applications requiring durability and mechanical resilience.
Implementation Method 1
epoxy group-containing cyclic siloxanes are linked through a linking group gives a cured product with improved flexibility and crack resistance through polymerization of epoxy groups
Data Source
AI summary
This epoxy group-containing cyclic organopolysiloxane represented by general formula (1) provides a cured product having excellent crack resistance and flexibility. (R1 to R4 each independently represent a C1-C20 monovalent hydrocarbon group with, optionally, an oxygen atom interposed; Y represents a bivalent hydrocarbon group; ZI and Z2 each independently represent a C1-C20 monovalent hydrocarbon group with, optionally, an oxygen atom interposed, an epoxy group-containing monovalent organic group with, optionally, an oxygen atom interposed, an alkoxysilyl alkyl group, or a hydrogen atom, but at least one thereamong is an epoxy group-containing monovalent organic group with, optionally, an oxygen atom interposed; n1 and n2 each independently represent an integer satisfying 1 to 5 and n1 + n2 = 3 to 6; n3 and n4 each independently represent an integer satisfying 1 to 5 and n3 + n4 = 3 to 6; and m represents an integer of 1 to 11.)