Functionalized Lignin Antioxidant for Rubber Compounds

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Solution Overview

Problem

Current antioxidant agents used in rubber compounds for pneumatic tire parts, such as paraphenylenediamines and phenol derivatives, have limitations in sustainability and effectiveness, particularly under varying environmental conditions and mechanical stress, while non-functionalized lignin's antioxidant properties diminish beyond 50% terpene functionalization.

Innovation Solution

Incorporating functionalized lignin with terpene groups (10-60% functionalization of phenolic hydroxyl groups) as an antioxidant agent in rubber compounds, derived from Kraft lignin, to enhance the compounds' resistance to oxidation and maintain mechanical properties over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional petroleum-derived antioxidant agents (PPD, phenol derivatives) are used, then effective antioxidant protection is achieved, but sustainability and environmental compatibility deteriorate

Engineering Contradiction:
Improveantioxidant protection effectivenessVSAvoidenvironmental sustainability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical structure of lignin by controlling the degree of terpene functionalization (10-60% of phenolic hydroxyl groups) to optimize antioxidant performance. This parameter change transforms a naturally sustainable material into an effective antioxidant that matches or exceeds conventional agents while maintaining environmental compatibility.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes lignin, a waste byproduct from the paper industry, converting an inexpensive and abundant renewable resource into a high-performance antioxidant. This approach replaces expensive petroleum-derived agents with a sustainable, cost-effective alternative that can be readily discarded without environmental harm.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If non-functionalized lignin is used as antioxidant agent, then sustainability is improved, but antioxidant effectiveness deteriorates due to limited stability under varying environmental conditions

Engineering Contradiction:
Improveenvironmental sustainabilityVSAvoidantioxidant effectiveness under stress
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent creates a composite material by chemically functionalizing lignin with terpene groups. This composite structure combines the sustainability of natural lignin with the enhanced stability and antioxidant effectiveness of terpene modifications, achieving both environmental compatibility and reliable performance under mechanical stress and varying temperatures.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies chemical modification through controlled etherification or esterification reactions to introduce terpene groups onto lignin molecules. By adjusting the degree of functionalization (10-60% of phenolic hydroxyl groups), the patent optimizes the balance between maintaining lignin's natural sustainability and enhancing its antioxidant effectiveness under environmental stress.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If high degree of terpene functionalization (>50%) is applied to lignin, then sustainability and potential effectiveness are improved, but antioxidant capacity deteriorates significantly

Engineering Contradiction:
Improvesustainability and potential effectivenessVSAvoidantioxidant capacity
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent identifies and exploits the optimal parameter range for terpene functionalization (10-60% of phenolic hydroxyl groups). Within this range, the patent achieves the best balance between maintaining antioxidant capacity and incorporating sustainable terpene groups. Exceeding 50% functionalization is avoided as it depletes the phenolic hydroxyl groups necessary for antioxidant activity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies partial functionalization rather than complete modification of lignin's phenolic hydroxyl groups. By limiting terpene attachment to 10-60% of available groups, the patent preserves sufficient native phenolic functionality for antioxidant action while incorporating enough terpene groups to enhance stability and performance under environmental stress.

Inventive Principle:
Principle #16Partial or excessive 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

The use of functionalized lignin as an antioxidant agent in rubber compounds improves the maintenance of mechanical properties over time, outperforming both conventional petroleum-derived agents and non-functionalized lignin by maintaining lower percentage increases in M300 values after aging, thus extending the lifespan of tire parts.

Implementation Method 1

antioxidant agents are materials that are added to compounds that are susceptible to oxidation, such as polymers, in order to inhibit or slow down the oxidation processes

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentUS11046837B2Rubber compounds for pneumatic tyre parts comprising lignin as an antioxidant agent
Publication Date: 2021.06.29 BRIDGESTONE CORP

AI summary

Rubber compound for preparing pneumatic tyre parts comprising a cross-linkable unsaturated chain polymer base, a filler, a vulcanization system and one or more antioxidant agents. The antioxidant agents comprise functionalized lignin with —OR groups, where R is a terpene group with a total number of carbon atoms of between 6 and 16. The —OR groups deriving from the functionalization of 10 to 60% of the lignin phenolic hydroxyl groups.