Polysulphidic Silane Coupling Agents for Rubber Mixtures
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Solution Overview
Problem
Rubber mixtures containing organo(alkyl polyether silanes suffer from low elongation at break and significant alcohol emission during mixing, which affects their performance and efficiency.
Innovation Solution
The use of polysulphidic organo(alkyl polyether silanes with specific alkyl polyether groups and molecular structures, such as those in the general formula [(X)(X′)(X″)Si—RI]2—Sm, which reduce alcohol emission and enhance elongation at break by improving the interaction between filler and elastomer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If methoxy- or ethoxy-substituted silanes are used as coupling agents, then the coupling reaction proceeds rapidly and good interaction between filler and elastomer is achieved, but considerable amounts of alcohol (methanol or ethanol) are liberated during and after coupling
Solution Approach 1:
The patent changes the alkoxy substituent parameter from short-chain (methoxy/ethoxy) to long-chain (C3-C25 alkoxy) groups. This parameter change maintains the coupling functionality while significantly reducing alcohol emission during the coupling reaction, as the longer chain alcohols are less volatile and emit less during processing.
Solution Approach 2:
The patent uses long-chain alkoxy groups that produce less problematic byproducts. The resulting long-chain alcohols are less volatile and environmentally problematic compared to methanol/ethanol, effectively treating the byproduct issue by choosing substituents that generate more acceptable waste products.
2Object-generated harmful factors
If organo(alkyl polyether silanes) are used in rubber mixtures, then alcohol emission during mixing is reduced, but elongation at break is low
Solution Approach 1:
The patent creates a composite structure by combining silane coupling agents with alkyl polyether groups. This composite molecular structure integrates the filler-coupling capability of silanes with the elastomer-compatible polyether chains, achieving both reduced alcohol emission and improved elongation at break through the synergistic effect of the combined functional groups.
Solution Approach 2:
The patent introduces local quality by adding specific alkyl polyether side chains (with 10-30 carbon atoms) to the silane core structure. These localized polyether segments provide elastomer compatibility and improve elongation properties, while the core silane structure maintains the filler coupling function and low alcohol emission characteristics.
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 polysulphidic organo(alkyl polyether silanes significantly reduce alcohol emission and improve elongation at break in rubber mixtures, leading to better performance and processing characteristics compared to traditional silanes.
Implementation Method 1
These coupling agents or bonding agents form bonds with the filler and also with the elastomer and thus bring about good interaction between the filler surface and the elastomer
Implementation Method 2
the use of commercially available silane coupling agents (DE 22 55 577) having three alkoxy substituents on the silicon atom leads to liberation of considerable amounts of alcohol during and after coupling to the filler
Data Source
AI summary
Rubber mixtures are disclosed comprising (A) at least one styrene-butadiene rubber, (B) at least one filler and (C) at least one polysulphidic organo(alkyl polyether silane) of the general formula I[(X)(X′)(X″)Si—RI]2—Sm I.The mixtures are prepared by mixing at least one styrene-butadiene rubber, and at least one filler and one polysulphidic organo(alkyl polyether silane) of the formula (I). The rubber mixtures can be used for the production of mouldings.