Functionalized Liquid Polybutadiene Tread Rubber Abrasion Resistance

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Solution Overview

Problem

Tread rubber compounds face challenges in achieving improved abrasion resistance without compromising other essential properties such as cure, functionality of the matrix polymer, and elastic modulus, while also reducing the use of process oil without affecting processability.

Innovation Solution

A tread rubber compound incorporating functionalized liquid polybutadiene, which is reacted with an unsaturated acid anhydride, combined with zinc oxide to form long, stable crosslinks, and used as a partial replacement for process oil, maintaining the compound's properties and enhancing abrasion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional methods are used to improve abrasion resistance, then abrasion resistance is improved, but other useful properties such as cure, functionality of the matrix polymer, and elastic modulus are significantly impacted

Engineering Contradiction:
Improveabrasion resistanceVSAvoidcure and functionality
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the polybutadiene by functionalizing it with acid anhydride groups, transforming it from a conventional additive to a crosslinking agent. This parameter change allows the material to improve abrasion resistance through controlled crosslinking while maintaining compatibility with the matrix polymer and preserving other useful properties like cure characteristics and elastic modulus.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite system by combining functionalized liquid polybutadiene with zinc oxide to form a crosslinking network within the rubber matrix. This composite approach enables the simultaneous achievement of improved abrasion resistance and maintained functionality, as the crosslinked structure provides wear resistance while the controlled interaction with zinc oxide preserves the matrix polymer's essential properties.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If the amount of process oil is reduced, then processability is improved, but other useful properties are negatively impacted

Engineering Contradiction:
ImproveprocessabilityVSAvoiduseful properties
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the functional parameters of the polybutadiene from a simple lubricant to an active crosslinking component through acid anhydride functionalization. This transformation allows the material to provide process oil benefits for manufacturability while simultaneously contributing to the structural integrity and useful properties of the cured rubber through crosslinking.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The functionalized liquid polybutadiene serves multiple functions: it acts as a processing aid similar to process oil during manufacturing, and simultaneously serves as a crosslinking agent that improves abrasion resistance and maintains useful properties in the final product. This multi-functionality resolves the contradiction between ease of manufacture and preservation of useful properties.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution effectively improves abrasion resistance by up to 13% while maintaining the compound's other properties, and the use of functionalized liquid polybutadiene as a partial oil replacement enhances crosslinking without negatively impacting the rubber's physical characteristics.

Implementation Method 1

The liquid polybutadiene is functionalized by the reaction with an unsaturated acid anhydride... combined with zinc oxide to form long, stable crosslinks

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Data Source

PatentUS8975324B2Tread rubber compounds having improved abrasion resistance using functionalized liquid polybutadiene
Publication Date: 2015.03.10 BRIDGESTONE CORP

AI summary

A tread rubber composition having improved abrasion resistance is provided. The tread rubber composition comprises a conjugated diene polymer or copolymer, at least one filler, from 2 to 10 phr of liquid polybutadiene, from 2 to 5 phr of zinc oxide and from 1 to 100 phr of process oil. The liquid polybutadiene is functionalized by reaction with unsaturated acid anhydride, has a number average molecular weight of from 3 to 8 kg/mol and an acid number of from 40 to 80. Also provided are methods for preparing the tread rubber composition comprising mixing of the foregoing ingredients by master-batch and final batch steps whereby the abrasion resistance of the tread rubber composition is improved.