Modified Silicate Fibre Elastomer for Low Rolling Resistance Tyres

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Solution Overview

Problem

Current elastomeric materials used in tires, particularly those filled with silica, exhibit high hysteresis and rolling resistance, which is undesirable for low rolling resistance tires, and suffer from mechanical property deterioration under high deformations due to the Payne effect, limiting their performance in demanding conditions.

Innovation Solution

The use of nanometric-sized silicate fibers, modified by a controlled acid process to partially remove magnesium, which preserves their needle-shaped morphology and crystalline structure, is incorporated into the elastomeric materials to reduce hysteresis and maintain dynamic modulus at high strains, thereby enhancing the tire's mechanical properties and reducing rolling resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If silica fillers are used to reduce hysteresis, then rolling resistance decreases, but mechanical properties deteriorate under high deformations due to Payne effect

Engineering Contradiction:
ImprovehysteresisVSAvoidmechanical properties under high deformation
Core Design Contradiction:
Loss of energyVSStrength

Solution Approach 1:

The patent employs a composite filler system combining modified silicate fibres with conventional silica or carbon black. The silicate fibres provide structural reinforcement that maintains mechanical strength under high deformation, while the silica or carbon black controls hysteresis and rolling resistance. This composite approach allows simultaneous optimization of both contradictory properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the physical and chemical parameters of silicate fibres through controlled acid treatment, which removes magnesium ions and creates surface silanol groups. This parameter change enhances the fibres' compatibility with the elastomeric matrix and improves stress transfer, thereby maintaining mechanical properties at high deformations while the fibre morphology controls hysteresis.

Inventive Principle:
Principle #35Parameter changes

2Strength

If carbon black is used for reinforcement, then static mechanical properties improve, but hysteresis increases leading to higher rolling resistance

Engineering Contradiction:
Improvestatic mechanical propertiesVSAvoidhysteresis
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The patent creates a composite filler system where modified silicate fibres provide the primary reinforcement for static mechanical properties, replacing or reducing carbon black content. The fibres' high aspect ratio and surface area-to-volume ratio enable effective stress transfer, maintaining tensile strength and elongation while reducing the hysteresis-associated energy loss of carbon black.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent extracts or removes magnesium ions from the silicate fibre structure through acid treatment, transforming the fibres into a more reactive form that better interfaces with the elastomeric matrix. This extraction process enhances the fibres' reinforcing efficiency, allowing lower filler loads to achieve the same mechanical properties, thereby reducing overall hysteresis.

Inventive Principle:
Principle #2Taking out (Extraction)

3Loss of energy

If silicate fibres are used to reduce hysteresis, then rolling resistance decreases, but reinforcement activity is insufficient under strong stress

Engineering Contradiction:
ImprovehysteresisVSAvoidreinforcement under strong stress
Core Design Contradiction:
Loss of energyVSStrength

Solution Approach 1:

The patent applies controlled acid treatment to modify the chemical parameters of silicate fibres, removing magnesium ions and generating surface silanol groups. This parameter change increases the fibres' surface reactivity and compatibility with the elastomeric matrix, enabling effective stress transfer even under strong deformation conditions, thereby providing sufficient reinforcement while maintaining low hysteresis.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary modification of the silicate fibres through acid treatment before incorporating them into the elastomeric composition. This preliminary action pre-establishes the fibres' surface chemistry and morphology, ensuring optimal interfacial adhesion and stress transfer capability from the outset, which enables the fibres to effectively reinforce the material under strong stress conditions.

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

The modified silicate fibers significantly reduce hysteresis and the Payne effect, leading to improved static and dynamic mechanical properties, resulting in lower rolling resistance and better reinforcement even under extreme stress conditions, making them suitable for ultra-low rolling resistance and self-supporting tires.

Implementation Method 1

adding at least one acid compound to the suspension, allowing the reaction, up to extracting from 10% to 70% by weight of magnesium from the fibres

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Data Source

PatentEP3289013B1Vulcanisable elastomeric materials for components of tyres comprising modified silicate fibres, and tyres thereof
Publication Date: 2019.07.24 PIRELLI TYRE SPA
  • EP3289013B1 patent drawingFigure 1
  • EP3289013B1 patent drawingFigure 2
  • EP3289013B1 patent drawingFigure 3A~3B

AI summary

The present invention relates to new vulcanisable elastomeric compositions for components of tyres, comprising modified silicate fibres as fillers. Moreover, the invention relates to components tyres, comprising elastomeric materials obtainable by vulcanisation of said compositions, and tyres for vehicles comprising one or more of said components. The vulcanised elastomeric materials according to the invention are characterised by good static and dynamic mechanical properties, in particular by particularly low hysteresis. Advantageously, the tyres of the invention comprising one or more of said components have a reduced rolling resistance.