Room Temperature Curable Organopolysiloxane Composition for Electronic Sealing
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Solution Overview
Problem
Room temperature curable organopolysiloxane compositions used in electric/electronic applications have poor mechanical properties such as breaking stress and elongation, affecting their reliability and storage stability.
Innovation Solution
A composition comprising an organopolysiloxane with specific alkoxysilyl-containing groups, an organopolysiloxane resin with controlled silanol and alkoxy group content, an alkoxysilane, and a condensation-reaction catalyst, which cures at room temperature upon moisture exposure, forming a product with improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If room temperature curable organopolysiloxane compositions are used as sealants or adhesives, then heating is not required for curing, but the cured products have poor mechanical properties such as breaking stress and elongation
Solution Approach 1:
The patent uses a composite system combining organopolysiloxane (A) with specific alkoxysilyl-containing groups, organopolysiloxane resin (B) with controlled silanol and alkoxy content, alkoxysilane (C), and condensation catalyst (D). This composite composition achieves both room temperature curing capability and improved mechanical properties including breaking stress of 0.7-2.5 MPa and elongation of 30-300%.
Solution Approach 2:
The patent optimizes specific parameters including the molecular weight and structure of organopolysiloxane (A), the silanol content (30-54 mol%) and alkoxy content (46-70 mol%) of organopolysiloxane resin (B), and the ratios of components. These parameter changes enable the composition to cure at room temperature while achieving breaking stress ≥0.7 MPa and elongation ≥30%.
2Reliability
If conventional organopolysiloxane compositions are used, then adhesion to substrate is good, but storage stability is poor
Solution Approach 1:
The patent carefully controls the silanol content at 30-54 mol% and alkoxy content at 46-70 mol% in organopolysiloxane resin (B), along with optimizing the molecular structure of organopolysiloxane (A). These parameter optimizations prevent premature curing during storage while maintaining good adhesion to substrates, achieving storage stability of at least 6 months.
Solution Approach 2:
The patent uses alkoxysilane (C) and condensation catalyst (D) as intermediaries that control the curing process. The catalyst system enables controlled condensation reaction between silanol and alkoxy groups, maintaining composition stability during storage while ensuring proper adhesion and curing performance when applied.
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 storage stability and mechanical properties, including high breaking stress and elongation, and enhances the reliability of electric/electronic apparatuses due to its good adhesion and thermal shock stability.
Implementation Method 1
room temperature curable organopolysiloxane composition that can cure at room temperature by contact with moisture in air
Implementation Method 2
an alkoxysilane or its partial hydrolysis and condensation product
Data Source
AI summary
A room temperature curable organopolysiloxane composition comprises: (A) an organopolysiloxane having alkoxysilyl-containing groups at both molecular terminals; (B) an organopolysiloxane resin; (C) an alkoxysilane; and (D) a condensation-reaction catalyst. The room temperature curable organopolysiloxane composition exhibits good to excellent storage stability. In addition, the room temperature curable organopolysiloxane composition can form a cured product exhibiting good to excellent mechanical properties.