Emulsion SBR Rubber Composition Kneading Process for Low Heat Build-Up
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Solution Overview
Problem
Current rubber compositions for tires face challenges in achieving low heat build-up and enhanced wear resistance, particularly in emulsion-polymerized styrene-butadiene copolymer rubber, where the activity of silane coupling agents is reduced due to other mixed components and kneading conditions are not optimally considered.
Innovation Solution
A process is developed to produce a rubber composition by defining the total amount of organic acid, including stearic acid, in the production of emulsion-polymerized styrene-butadiene copolymer rubber, and incorporating a silane coupling agent and vulcanization accelerators like guanidine, sulfenamide, and thiazole compounds, with specific kneading steps to enhance the coupling function and improve low heat build-up properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a silane coupling agent is added to prevent inorganic filler aggregation, then the low heat build-up property is improved, but the activity of the silane coupling agent is reduced due to other mixed components
Solution Approach 1:
The patent applies preliminary action by adding the silane coupling agent in the first kneading step before other components that might reduce its activity. This timing ensures the coupling agent can effectively interact with the inorganic filler surface before competing substances are introduced, maintaining its coupling function while achieving low heat build-up properties.
Solution Approach 2:
The patent segments the mixing process into multiple distinct kneading steps, with each step having specific purposes. The silane coupling agent is handled separately in the first step, allowing its activity to be preserved and optimized independently from other mixing operations, thereby resolving the contradiction between its effectiveness and the presence of other components.
2Strength
If multiple components are mixed to enhance coupling function, then the wear resistance is improved, but the kneading conditions become complex and reduce coupling agent activity
Solution Approach 1:
The patent divides the kneading process into multiple sequential steps, each with specific components and conditions. This segmentation allows complex multi-component mixing to be organized systematically, where the silane coupling agent is processed in controlled conditions in the first step, preventing activity reduction while still achieving enhanced wear resistance through subsequent additions of other components.
3Reliability
If the total amount of organic acid is controlled, then the silane coupling agent activity is maintained, but the wear resistance and low heat build-up properties are not sufficiently enhanced
Solution Approach 1:
The patent optimizes the total amount of organic acid as a critical parameter, controlling it within a specific range (0.1-5 parts by mass per 100 parts of emulsion-polymerized styrene-butadiene copolymer rubber). This parameter control maintains silane coupling agent activity while the patent achieves enhanced wear resistance through the combined effect of proper coupling agent usage and optimized organic acid content.
Solution Approach 2:
The patent applies local quality by controlling organic acid content specifically in relation to the emulsion-polymerized styrene-butadiene copolymer rubber component. This localized optimization ensures the coupling agent remains active in the rubber matrix while still achieving sufficient wear resistance and low heat build-up properties through the tailored composition.
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 effectively suppresses the reduction of the silane coupling agent's activity, leading to improved low heat build-up and wear resistance in tires, with a tire produced using this composition exhibiting enhanced rolling resistance and durability.
Implementation Method 1
a silane coupling agent is used for preventing the inorganic filler from being aggregated in the rubber composition
Implementation Method 2
the total amount of an acidic component, which includes an organic acid, such as stearic acid, and an organic acid contained in a residue of an emulsifier
Data Source
AI summary
The present invention relates to a process of producing a rubber composition containing a rubber component (R) containing emulsion-polymerized styrene-butadiene copolymer rubber containing from 0 to 3.5 parts by mass of an organic acid per 100 parts by mass of the emulsion-polymerized styrene-butadiene copolymer rubber, a filler containing an inorganic filler (T), a silane coupling agent (U), and at least one vulcanization accelerator (V) selected from a guanidine compound, a sulfenamide compound and a thiazole compound, the process comprising three or more steps of kneading the rubber composition, the rubber component (R), the whole or a part of the inorganic filler (T) and the whole or a part of the silane coupling agent (U) being added and kneaded in a first step (X) of kneading, the vulcanization accelerator (V) being added and kneaded in a step (Y) that is a second or later step before a final step, and a vulcanizing agent being added and kneaded in the final step (Z).