One-Component Organopolysiloxane Adhesive for Low-Temperature Curing
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Solution Overview
Problem
Existing curable organopolysiloxane compositions face issues with storage stability, insufficient adhesion to poorly adhesive materials, and require high temperatures for curing, leading to handling difficulties and inadequate adhesive strength.
Innovation Solution
A one-component curable organopolysiloxane composition containing organopolysiloxanes with alkenyl and silicon atom-bonded hydrogen groups, a photo-active hydrosilylation reaction catalyst, a condensation reaction catalyst, a curing inhibitor, and an adhesion imparting agent with a terminal trialkoxysilyl group, allowing for low-temperature curing and improved adhesion to materials like polycarbonate and metal surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a curable organopolysiloxane composition uses both a hydrosilylation reaction catalyst and a condensation reaction catalyst simultaneously, then low-temperature curability is improved, but the composition becomes two-component type requiring mixing before use, resulting in short pot life and handling problems
Solution Approach 1:
The patent combines both the hydrosilylation reaction catalyst (platinum complex) and condensation reaction catalyst (titanium compound) into a single one-component composition. The catalysts are kept separate within the composition using a separating agent, allowing both curing mechanisms to function simultaneously at low temperatures without requiring external mixing or handling of multiple components.
Solution Approach 2:
The patent introduces a separating agent (such as a surfactant or stabilizer) as an intermediary substance that prevents the hydrosilylation and condensation catalysts from premature reaction while maintaining their individual activities. This separating agent allows the composition to remain stable during storage and handling while enabling both curing reactions to proceed at low temperatures when applied.
2Area of stationary object
If the composition is used in thin film form, then adhesion coverage is improved, but sufficient initial adhesion and adhesive strength cannot be obtained
Solution Approach 1:
The patent creates a composite curing system that combines both hydrosilylation and condensation reaction mechanisms within the same composition. The hydrosilylation reaction provides rapid initial curing and strong adhesion even in thin film form, while the condensation reaction contributes to overall network formation and durability, achieving both sufficient initial adhesion and final adhesive strength in thin applications.
3Productivity
If heating to high temperature is used for curing, then curing speed is improved, but adhesion to poorly adhesive materials such as polycarbonate and PPS resin is insufficient
Solution Approach 1:
The patent changes the chemical parameters of the curing system by incorporating both hydrosilylation and condensation reaction catalysts. This dual-mechanism approach enables effective curing at low temperatures (room temperature to 80°C), preventing thermal degradation of sensitive base materials like polycarbonate and PPS resin while achieving reliable adhesion. The condensation catalyst specifically enhances bonding to these poorly adhesive materials through silane-based chemical bonding.
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, adhesion to poorly adhesive resins and metals at low temperatures, and can be rapidly cured at higher temperatures when needed, ensuring reliable adhesion and durability in electronic components.
Implementation Method 1
a photo-active hydrosilylation reaction catalyst
Implementation Method 2
a condensation reaction catalyst
Implementation Method 3
an adhesion imparting agent having at least one terminal trialkoxysilyl group
Data Source
AI summary
A one-component curable organopolysiloxane composition that has excellent storage stability, favorable curability and adhesion at relatively low temperatures, and an appropriate pot life is provided. In particular, the composition has excellent curability even at temperatures of 80° C. or lower and excellent adhesion to resins such as polyester, polyphenylene sulfide, and the like. Furthermore, the composition can be cured in a short period of time by increasing the temperature to a high temperature when rapid curing is required. The composition comprises: (A) an organopolysiloxane having at least two alkenyl groups in each molecule thereof; (B) an organopolysiloxane having at least two silicon atom-bonded hydrogen atoms in a molecule; (C) a photo-active hydrosilylation reaction catalyst; (D) a condensation reaction catalyst; (E) a curing inhibitor; and (F) an adhesion imparting agent having at least one terminal trialkoxysilyl group.