Room-Temperature Silicone Rubber Adhesion and Oil Bleeding
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Solution Overview
Problem
Room-temperature-curable silicone rubber compositions exhibit insufficient adhesion to substrates and suffer from oil bleeding during curing.
Innovation Solution
A composition comprising a mixture of organopolysiloxanes with alkoxysilyl-containing groups, an organopolysiloxane lacking hydroxyl and alkoxy groups but with silicon-bonded alkenyl groups, an alkoxysilane or its hydrolyzed condensate, and a condensation-reaction catalyst, which cures at room temperature upon moisture exposure, enhancing adhesion and preventing oil bleeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a room-temperature-curable silicone rubber composition consisting of an organopolysiloxane having at least two alkoxysilyl-containing groups in each molecule, an alkoxysilane, and an organic titanium compound is used, then the composition can cure at room temperature by contact with moisture in air, but the adhesion to substrates is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters by introducing a specific organopolysiloxane component (B) containing silicon-bonded alkenyl groups and adjusting the molecular structure of component (A) to have controlled alkoxysilyl-containing groups. This compositional parameter change enables the system to achieve both room temperature curing capability and improved substrate adhesion through enhanced chemical interaction with the substrate surface.
Solution Approach 2:
The patent creates a composite silicone rubber composition by combining multiple organopolysiloxane components with different functional groups (alkoxysilyl-containing groups in component A and silicon-bonded alkenyl groups in component B), along with alkoxysilane and organic titanium compound. This composite material approach allows the system to simultaneously achieve room temperature curing through moisture reaction and strong adhesion through the alkenyl group interactions with the substrate.
2Ease of manufacture
If conventional room-temperature-curable silicone rubber compositions are used, then the composition can be applied and cured easily, but oil bleeding occurs during curing
Solution Approach 1:
The patent modifies the chemical composition by incorporating organopolysiloxane component (B) with silicon-bonded alkenyl groups and controlling the molecular structure of component (A). This compositional change alters the curing mechanism to proceed through a different chemical pathway that prevents oil bleeding while maintaining ease of application and room temperature curing capability.
Solution Approach 2:
The patent converts the potential harmful effect of oil bleeding during curing into a beneficial outcome by using the alkoxysilyl-containing groups and silicon-bonded alkenyl groups to create a controlled curing reaction. The chemical reaction pathway is designed to consume the reactive components in a way that produces strong adhesion without the harmful side effect of oil bleeding, transforming what would be a defect into a feature.
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 achieves good adhesion to substrates and suppresses oil bleeding, improving the reliability of electronic devices by forming a silicone rubber cured product with enhanced mechanical strength and processability.
Implementation Method 1
Room-temperature-curable silicone rubber compositions consisting of an organopolysiloxane having at least two alkoxysilyl-containing groups in each molecule, an alkoxysilane, and an organic titanium compound cure at room temperature by contact with moisture in air
Implementation Method 2
an alkoxysilane or its partial hydrolysis and condensation product
Implementation Method 3
a condensation reaction catalyst
Data Source
AI summary
To provide a room-temperature-curable silicone rubber composition exhibiting good adhesion to a substrate contacted during curing and capable of suppressing the occurrence of oil bleeding. The problem is solved by a room-temperature-curable silicone rubber composition containing (A) a mixture of (A1) an organopolysiloxane having at least two specified alkoxysilyl-containing groups in the molecular and (A2) an organopolysiloxane having one specified alkoxysilyl-containing group in the molecular; (B) an organopolysiloxane lacking a hydroxyl group and an alkoxy group; (C) an alkoxysilane; and (D) a condensation-reaction catalyst.