Tire Rubber Composition Silica Dispersibility via pH-Controlled Kneading

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Solution Overview

Problem

Conventional tire rubber composition manufacturing methods face challenges in achieving balanced low fuel consumption, wear resistance, and wet grip performance due to antagonistic reactions between silica and silane coupling agents, leading to poor dispersibility and uniformity of silica within the rubber matrix.

Innovation Solution

A method involving a base kneading process where a rubber component, silane coupling agent, and silica with a BET specific surface area of 210 m2/g or more are kneaded, followed by the addition of a vulcanization accelerator to promote hydrolysis and polycondensation reactions, maintaining a pH of 6.5 or less initially and 8.0 or more after adding the accelerator, and a finishing kneading process with a vulcanization agent to ensure uniform bonding and improved dispersibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If silica and silane coupling agent are mixed in conventional methods, then the rubber composition can be manufactured, but the silica dispersibility and uniformity deteriorate due to antagonistic reactions

Engineering Contradiction:
Improvesilica dispersibilityVSAvoidantagonistic reactions
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The silane coupling agent is pre-granulated with silica before being mixed with the rubber compound. This preliminary granulation action prevents direct contact and antagonistic reactions between the silane coupling agent and silica during conventional mixing, thereby improving silica dispersibility and uniformity in the final rubber composition

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The granulation process creates an intermediary structure where the silane coupling agent is encapsulated or bound with silica particles. This intermediary granulated form acts as a protective medium that prevents harmful antagonistic reactions while allowing controlled interaction during vulcanization, resolving the contradiction between reactivity and dispersibility

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If multiple components are kneaded together, then the rubber composition is formed, but the manufacturing process complexity increases

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidkneading process complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The manufacturing process is segmented into distinct stages: first granulating the silane coupling agent with silica, then mixing with other rubber components, and finally vulcanizing. This segmentation allows each stage to be optimized independently, simplifying the overall manufacturing process while maintaining product quality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The silane coupling agent and silica are pre-granulated before being incorporated into the rubber compound. This preliminary action reduces the number of mixing steps required and prevents compatibility issues during kneading, thereby simplifying the manufacturing process and reducing equipment complexity

Inventive Principle:
Principle #10Preliminary action

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 enhances the dispersibility of silica, resulting in improved low fuel consumption, wear resistance, and wet grip performance while preventing gelation and aggregation, thereby achieving a well-balanced performance improvement.

Implementation Method 1

adding a vulcanization accelerator to promote hydrolysis and polycondensation reactions

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

adding a vulcanization accelerator to promote hydrolysis and polycondensation reactions

Methodology Applied
Scientific EffectPolycondensation:

Implementation Method 3

adding a vulcanization accelerator to a first kneaded material including the rubber component, the silane coupling agent and the silica

Methodology Applied
Scientific EffectVulcanization:

Data Source

PatentUS10351697B2Tire rubber composition manufacturing method and tire rubber composition
Publication Date: 2019.07.16 SUMITOMO RUBBER INDUSTRIES LTD

AI summary

A method for manufacturing a tire rubber composition includes kneading a rubber component, a silane coupling agent and a silica having a BET specific surface area of 210 m2/g or more, adding a vulcanization accelerator to a first kneaded material including the rubber component, silane coupling agent and silica, kneading a first resulting mixture including the rubber component, silane coupling agent, silica and vulcanization accelerator such that a second kneaded material including the rubber component, silane coupling agent, silica and vulcanization accelerator is obtained, adding a vulcanization agent to the second kneaded material including the rubber component, silane coupling agent, silica and vulcanization accelerator, and kneading a second resulting mixture including the rubber component, silane coupling agent, silica, vulcanization accelerator and vulcanization agent. The first kneaded material has a pH of 6.5 or less, and the second kneaded material has a pH of 8.0 or more.