Guayule Rubber Silica Compounds for Tire Performance

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Solution Overview

Problem

The incorporation of silica/silane into natural rubber compounds using conventional in-situ silica mixing technology is hindered by issues with rolling resistance, wear, and tear strength, primarily due to the presence of non-rubber materials like proteins, which interfere with the silanization reaction, and existing solutions like pretreated silica are costly.

Innovation Solution

A rubber composition comprising guayule rubber and 15 to 90 phr silica, with reduced Hevea protein content and trace amounts of resins, using hydrophobated silica and a silica coupler to enhance silica incorporation and processing, allowing for improved physical properties and processability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional in-situ silica mixing technology is used with natural rubber compounds, then silica incorporation is attempted, but rolling resistance, wear, and tear strength deteriorate due to protein interference with silanization reaction

Engineering Contradiction:

Improvetire performanceVSAvoidprocessability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts and removes proteins from natural rubber latex through a multi-step process involving coagulation, washing, and extraction with organic solvents. This removal of harmful proteins eliminates their interference with the silanization reaction, allowing silica to be successfully incorporated into the rubber compound without compromising tire performance or processability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies preliminary action by pre-treating the natural rubber latex to remove proteins before the silanization process. The debioing and extraction steps are performed in advance to create a protein-free or low-protein rubber base, ensuring that subsequent silica mixing and silanization reactions proceed without interference from protein contaminants

Inventive Principle:

Principle #10Preliminary action

2Reliability

If pretreated silica is used to overcome protein interference, then silica incorporation improves, but manufacturing cost increases significantly

Engineering Contradiction:

Improvesilica incorporationVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of pre-treating the silica to overcome protein interference (the conventional approach), the patent inverts the strategy by pre-treating the natural rubber latex to remove proteins before adding silica. This reversal eliminates the need for expensive pretreated silica while achieving the same goal of successful silanization and silica incorporation

Inventive Principle:

Principle #13The other way round (Inversion)

3Strength

If natural rubber with high protein content is used, then rubber elasticity and performance are maintained, but sensitivity to filler and oil type changes increases

Engineering Contradiction:

Improverubber elasticityVSAvoidsensitivity to filler and oil type

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The patent extracts proteins from natural rubber latex through systematic washing and extraction processes. By removing proteins that cause variability in rubber properties, the resulting compound shows reduced sensitivity to changes in filler and oil types, while maintaining the elastic properties provided by the natural rubber polymer structure

Inventive Principle:

Principle #2Taking out (Extraction)

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 use of guayule rubber with reduced protein content and hydrophobated silica results in lower Mooney viscosity and improved processability, indicating better tire performance and reduced sensitivity to filler and oil type changes, thus overcoming the limitations of existing in-situ silica/silane technology in natural rubber compounds.

Implementation Method 1

The use of guayule rubber with reduced protein content and hydrophobated silica results in lower Mooney viscosity and improved processability

Methodology Applied

Scientific EffectHydrophobation: Hydrophobe

Implementation Method 2

using hydrophobated silica and a silica coupler to enhance silica incorporation and processing

Methodology Applied

Scientific EffectSilane coupling: Chemical Bonding

Data Source

PatentUS10538600B2Natural rubber compounds with silica and use with tires

Publication Date: 2020.01.21 THE GOODYEAR TIRE & RUBBER CO

AI summary

A rubber composition including guayule rubber and 15 to 90 phr silica. The rubber can be cis-1,4 polyisoprene and include 15 to 90 phr silica and contain less than 20% of the proteins associated with Hevea rubber and further include at least a trace of resins present in other natural rubbers. The rubber can be cis-1,4 polyisoprene and further include between at least a trace and 3% by weight of resins present in guayule rubber. The rubber composition can further be comprised of a synthetic rubber and include between about 40-100 phr of guayule rubber, and silica. The silica can be hydrophobated.