Functionalized Silica Rubber Compound Processability
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Solution Overview
Problem
The use of trialkoxymercaptoalkyl-silanes in rubber compounds for pneumatic tire treads improves rolling and wear resistance but increases viscosity, leading to processability issues, which are mitigated by adding zinc oxide, but this reduces the effectiveness of the silane in rolling and wear resistance.
Innovation Solution
A process involving the use of functionalized silica with dicarboxylic acids allows for the use of un-blocked trialkoxymercaptoalkyl-silane without zinc oxide in the masterbatch, adding it during the productive mixing step with vulcanization components, maintaining processability and enhancing rolling and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trialkoxymercaptoalkyl-silane is used as silane bonding agent, then rolling resistance and wear resistance are improved, but viscosity increases causing processability problems
Solution Approach 1:
The patent extracts zinc oxide from the masterbatch preparation step, adding it only during the final mixing step. This removal of ZnO during masterbatch preparation prevents the blocking of silane sulfhydryl groups, allowing the silane to maintain its full reactivity and effectiveness in improving rolling and wear resistance without causing excessive viscosity increase that would compromise processability.
Solution Approach 2:
The patent performs preliminary functionalization of silica with dicarboxylic acids during masterbatch preparation, creating silane-silica interactions in advance. This preliminary action allows the silane to be pre-positioned on silica surfaces where it can effectively bond to the polymer base during vulcanization, improving rolling and wear resistance without requiring zinc oxide blocking during the preparation phase.
2Ease of manufacture
If zinc oxide is added during masterbatch preparation to reduce viscosity, then processability is improved, but effectiveness of silane in rolling and wear resistance is reduced
Solution Approach 1:
The patent performs preliminary functionalization of silica with dicarboxylic acids during masterbatch preparation, creating silane-silica interactions in advance. This preliminary action allows the silane to be pre-positioned on silica surfaces where it can effectively bond to the polymer base during vulcanization, improving rolling and wear resistance without requiring zinc oxide blocking during the preparation phase.
Solution Approach 2:
The patent extracts zinc oxide from the masterbatch preparation step, adding it only during the final mixing step. This removal of ZnO during masterbatch preparation prevents the blocking of silane sulfhydryl groups, allowing the silane to maintain its full reactivity and effectiveness in improving rolling and wear resistance without causing excessive viscosity increase that would compromise processability.
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
This approach enables full exploitation of trialkoxymercaptoalkyl-silane benefits in rolling and wear resistance without increasing viscosity, ensuring effective compound processing and performance.
Implementation Method 1
The silica is used in combination with silane bonding agents, which bind to the silanol groups of silica in order to inhibit the agglomeration thereof and, at the same time, to chemically bind it to the polymer base.
Implementation Method 2
Zinc oxide is able to block the sulfhydryl groups of the silane, reducing the reactivity thereof and thus avoiding the consequential processability problems.
Implementation Method 3
the use of a particular functionalized silica allows for the use of trialkoxymercaptoalkyl-silane without the simultaneous presence of ZnO within the masterbatch
Data Source
AI summary
A process for the preparation of a rubber compound for a pneumatic tyre portion. The process comprises a first non-productive mixing step, wherein, at least one cross-linkable unsaturated-chain polymer base, silica, a silane bonding agent comprised within the class of trialkoxymercaptoalkyl-silanes are mixed together and a productive mixing step, wherein, at least a vulcanization system and Zn oxide are added and blended to the compound under preparation. The silica is functionalized with dicarboxylic acids and the first non-productive mixing step does not comprise Zn oxide.