Polyaddition Silicone Adhesion via Silane Coupling Agent
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Solution Overview
Problem
The adhesion of silicone elastomers obtained by polyaddition-crosslinking of silicone compositions on substrates such as glass, metals, and thermoplastic resins is low, leading to spontaneous separation or low tensile force, which is inadequate for many applications requiring durable bonding.
Innovation Solution
A process involving a polyaddition-crosslinking silicone composition comprising organopolysiloxane, organohydrogenopolysiloxane, a specific additive with epoxy-functional and hydrogenosiloxyl units, organotitanium compound, and a platinum catalyst, applied to rigid substrates and crosslinked at controlled temperatures to achieve strong adhesion and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polyaddition-crosslinking silicone compositions are used, then the composition maintains good fluidity and storage stability, but the adhesion to substrates (glass, metals, thermoplastic resins) is low
Solution Approach 1:
The patent introduces a silane coupling agent as an intermediary substance between the silicone elastomer and the substrate. This coupling agent contains both silane groups (which bond with the silicone) and reactive groups (which bond with the substrate), thereby mediating the adhesion interface and resolving the contradiction between maintaining composition stability and improving adhesion strength
Solution Approach 2:
The patent creates a composite adhesion system by combining silicone elastomer, silane coupling agent, and substrate into a multi-component system. The silane coupling agent forms a bridge layer that integrates the organic silicone phase with the inorganic or organic substrate, achieving strong adhesion while preserving the individual properties of each component
2Strength
If adhesion-promoting additives are added to improve adhesion, then bonding strength increases, but the composition complexity and manufacturing difficulty increase
Solution Approach 1:
The silane coupling agent serves multiple functions simultaneously: it acts as an adhesion promoter, a crosslinking agent, and a compatibility modifier. This multi-functionality reduces the need for multiple separate additives, thereby improving adhesion while limiting composition complexity
Solution Approach 2:
The patent optimizes the molecular structure parameters of the silane coupling agent, specifically the length and type of the organic bridge between silane and reactive groups, to achieve maximum adhesion promotion with minimal additive concentration, thus balancing performance and complexity
3Productivity
If high crosslinking rate is achieved at desired temperatures, then industrial throughput increases, but storage stability before crosslinking may be compromised
Solution Approach 1:
The silane coupling agent is pre-incorporated into the silicone composition during manufacturing, but the actual crosslinking reaction is postponed until the desired processing stage. The silane groups remain dormant during storage and only activate upon heating or catalysis, allowing long-term storage stability while enabling rapid crosslinking when needed
Solution Approach 2:
The patent creates a dynamic system where the crosslinking state can be controlled: the composition remains uncrosslinked (fluid and stable) during storage and transport, then transitions to crosslinked (solid and adhesive) during processing. This dynamic control resolves the contradiction between storage stability and crosslinking rate
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 process results in composite articles with excellent adhesion and mechanical properties, maintaining stability during storage and ensuring high crosslinking rates, suitable for industrial throughput and diverse applications including electrical and electronic components.
Implementation Method 1
a polyaddition-crosslinking silicone composition comprising organopolysiloxane, organohydrogenopolysiloxane, a specific additive with epoxy-functional and hydrogenosiloxyl units, organotitanium compound, and a platinum catalyst
Implementation Method 2
The adhesion of silicone elastomers obtained by polyaddition-crosslinking of silicone compositions on substrates
Implementation Method 3
a specific additive with epoxy-functional and hydrogenosiloxyl units
Implementation Method 4
The adhesion of silicone elastomers obtained by polyaddition-crosslinking of silicone compositions on substrates such as glass, metals, and thermoplastic resins
Implementation Method 5
crosslinked at controlled temperatures to achieve strong adhesion and mechanical properties
Data Source
AI summary
A process is provided for preparing composite articles composed of a rigid glass, metal or thermoplastic resin substrate and of a silicone elastomer with good mechanical properties and good adhesion between the substrate and the silicone elastomer E such that there is a solid bond between the two parts. The composite articles are used in very diverse fields such as electrical and electronic equipment, motor vehicle and medical equipment, and they may be found, for example, in household appliances, consumer goods, medical equipment and sports and leisure articles.