Rubber Compound with Coumarone-Indene Resin for Tire Tread

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Solution Overview

Problem

Pneumatic vehicle tire tread compounds face a conflict between improving rolling resistance, abrasion resistance, and chip & chunk resistance, while also requiring optimal heating kinetics for vulcanization without excessive energy consumption or scorching during the manufacturing process.

Innovation Solution

A rubber mixture comprising diene rubber, coumarone-indene resin, and a vulcanization system with a specific accelerator-to-sulfur molar ratio, which balances rolling resistance and processability by extending scorch time without increasing full vulcanization time, allowing for efficient energy use and reliable processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the rubber compound is optimized for improved rolling resistance, then energy consumption is reduced, but abrasion resistance and chip & chunk resistance deteriorate

Engineering Contradiction:
Improverolling resistanceVSAvoidabrasion resistance
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the accelerator-to-sulfur molar ratio within 0.9 to 5, and using specific amounts of coumarone-indene resin (0.1 to 20 phr), to optimize the balance between rolling resistance and abrasion resistance. This quantitative parameter optimization allows the compound to achieve low energy consumption while maintaining durability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining coumarone-indene resin with diene rubber and a controlled vulcanization system. This composite formulation creates a synergistic effect where the resin modifies the polymer matrix properties, enabling simultaneous improvement in rolling resistance and maintenance of abrasion resistance that cannot be achieved with single materials.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the heating time during vulcanization is extended to ensure complete cross-linking, then structural durability is improved, but energy consumption increases

Engineering Contradiction:
Improvestructural durabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the vulcanization process by controlling the accelerator-to-sulfur molar ratio and using coumarone-indene resin, which enables complete cross-linking to occur within 5 to 15 minutes at standard vulcanization temperatures. This parameter optimization achieves full structural durability without the need for prolonged heating, thereby reducing energy consumption.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If the heating time is reduced to lower energy consumption, then energy efficiency is improved, but cross-linking becomes insufficient and durability is compromised

Engineering Contradiction:
Improveenergy consumptionVSAvoiddurability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the vulcanization system by using a specific accelerator-to-sulfur molar ratio (0.9 to 5) and incorporating coumarone-indene resin, which accelerates the cross-linking reaction. This allows the process to achieve complete cross-linking and full durability within a shortened time frame of 5 to 15 minutes, thereby reducing energy consumption without compromising reliability.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If the extrusion temperature is increased to improve processing speed, then productivity is improved, but scorching occurs leading to premature cross-linking

Engineering Contradiction:
Improveprocessing speedVSAvoidprocess stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent controls the thermal parameters by using coumarone-indene resin with specific softening point characteristics and controlling the accelerator-to-sulfur ratio. This parameter control allows extrusion at elevated temperatures for improved processing speed while preventing premature cross-linking, as the resin and controlled vulcanization system maintain process stability throughout the extrusion and vulcanization stages.

Inventive Principle:
Principle #35Parameter changes

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 rubber mixture achieves improved rolling resistance and process reliability with extended scorch time, enabling cost-effective and reliable production of tires with enhanced durability and performance.

Implementation Method 1

The heating kinetics of the rubber compound play an important role in industrialization. A crucial aspect is the duration of the necessary heating of the rubber compound and thus of the tire for vulcanization during the manufacturing process.

Methodology Applied
Scientific EffectHeating kinetics: Heating

Implementation Method 2

heating for too short a time leads to insufficient cross-linking of the polymer chains, which means that structural durability during driving is not guaranteed

Methodology Applied
Scientific EffectCross-linking: Chemical Bonding

Implementation Method 3

the sulfur bridges that have formed between the polymers are partially broken down again

Methodology Applied
Scientific EffectVulcanization: Chemical Bonding

Implementation Method 4

the extrusion through templates for the shaping of individual components leads to an increase in temperature. This can lead to the so-called 'scorching' of a mixture, i.e. premature, undesired pre-crosslinking.

Methodology Applied
Scientific EffectScorching: Heating

Data Source

PatentEP2700512B1Rubber compound
Publication Date: 2015.06.10 CONTINENTAL REIFEN DEUTSCHLAND GMBH

AI summary

The invention relates to a rubber compound, in particular for the treads of pneumatic vehicle tires. The rubber compound comprises the following components: - at least one diene rubber and - 0.1 to 20 phr of at least one coumaron-indene resin and - a vulcanization system comprising at least one accelerator and elemental sulfur and/or at least one sulfur-donating substance, wherein the molar ratio of accelerator to sulfur is 0.9 to 5, the total molar amount of sulfur consisting of elemental sulfur and the sulfur released by the sulfur-donating substance. The rubber compound exhibits an improvement in rolling resistance while maintaining other tire properties.Furthermore, the vulcanization time t10 and the full vulcanization time t90 of the rubber mixture enable economically sensible processing of the rubber mixture according to the invention with simultaneous process reliability, since the mixture does not show any susceptibility to scorch.