Alpha-Silane Coupling Agent for Catalyst-Free Silicone Rubber Curing
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Solution Overview
Problem
Current α-silane coupling agents used in silicone rubber applications suffer from high activity, easy discoloration, and poor stability, limiting their application and compliance with EU regulations regarding organotin catalyst usage.
Innovation Solution
Development of an α-silane coupling agent with adjustable reactivity and enhanced stability, featuring a nitrogen atom within cyclic groups or carbonyl compounds, which allows for fast curing of silicone rubber without catalysts and improved storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional α-silane coupling agents (ND-22, ND-42) are used, then the curing activity is high and adhesion is improved, but the stability is poor and discoloration occurs easily
Solution Approach 1:
The patent changes the chemical parameters of the silane coupling agent by introducing cyclic groups (morpholine, piperazine) or carbonyl compounds (ester, carbamido) at the α-position. This structural modification reduces the electron cloud density around the nitrogen atom, thereby adjusting the reactivity and stability parameters to achieve both high curing activity and excellent storage stability without discoloration
Solution Approach 2:
The patent creates composite functional groups by combining silane coupling agents with cyclic structures or carbonyl-containing groups. This composite structure integrates the adhesion benefits of silane coupling agents with the stability characteristics of cyclic/ carbonyl groups, resolving the contradiction between activity and stability
2Speed
If organotin catalysts are used to achieve fast curing, then the curing speed is improved, but the compliance with EU regulations is compromised due to organotin limitations
Solution Approach 1:
The patent extracts and eliminates the need for organotin catalysts by incorporating cyclic groups or carbonyl compounds directly into the silane coupling agent structure. The modified α-silane coupling agent becomes self-curing through its enhanced reactivity, removing the harmful organotin catalyst component while maintaining fast curing speed
Solution Approach 2:
The modified silane coupling agent performs self-curing without external catalysts. The cyclic groups or carbonyl compounds enable the agent to autonomously achieve fast curing through its intrinsic chemical properties, making the system self-sufficient and catalyst-free
3Strength
If the reactivity of silane coupling agent is increased, then the adhesion performance is improved, but the storage stability and shelf life are reduced
Solution Approach 1:
The patent optimizes the chemical parameters by introducing cyclic groups or carbonyl compounds that modulate the electron cloud density. This parameter adjustment creates a balanced state where the agent maintains high reactivity for strong adhesion while the cyclic/ carbonyl structure provides steric and electronic protection that enhances storage stability and prevents premature reaction
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 α-silane coupling agent achieves fast curing with a surface curing time under 2 minutes, maintains stability for 6 months at room temperature, and prevents yellowing, while reducing the need for organotin catalysts, enhancing its applicability and compliance with regulatory standards.
Implementation Method 1
the nitrogen atom of α-aminomethyl silane is located in cyclic groups, such as a morpholine compound or a group that reduces density of the electron cloud, such as carbonyl compounds (ester group, carbamido) etc.
Implementation Method 2
the activity of α-aminomethyl silane coupling agent can be adjusted by using different hydrolysis groups, so that the curing of the silicone rubber can be realized fast and without catalyst
Data Source
AI summary
The present invention discloses an α-silane coupling agent and application thereof. The α-silane coupling agent has a structure formula of formula (I):R1 is alkyl with 1 to 6 carbon atoms; R2 is alkyl with 1 to 6 carbon atoms; R3 is alkyl with 1 to 6 carbon atoms; R4 or R5 is selected from one of hydrogen, alkyl with 1 to 18 carbon atoms, aryl, benzyl, ester-containing group, carbamido-containing group or heterocyclic alkane; R4 and R5 are the same or different. The α-silane coupling agent is applied to silicone rubber, which can be cured without adding a catalyst, and the curing speed is fast; the α-silane coupling agent has strong reactivity, the surface curing time is less than 2 minutes; and the α-silane coupling agent has good stability, which can be stored stably under conditions at room temperature for 6 months, and does not easily turn yellow.