Multilayer Tread Composition for Wet-Grip Tire Performance

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Solution Overview

Problem

Tires lack excellent wet performance, which is crucial for safety on wet roads.

Innovation Solution

A tire design with a multilayer tread portion comprising a surface rubber layer and one or more inner rubber layers, where the surface rubber layer contains a lignin-based material in an amount equal to or greater than the inner rubber layers, enhancing hydrophilicity and grip on wet surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional rubber compounds are used in the tread portion, then the tire structure is simple and easy to manufacture, but the wet performance and grip on wet roads are insufficient

Engineering Contradiction:
Improvewet performanceVSAvoidtread structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The tread portion is divided into multiple rubber layers (first rubber layer, second rubber layer, third rubber layer) with different compositions and lignin-based material contents. This segmentation allows each layer to perform specific functions: the first layer provides hydrophilicity for wet grip, the second layer provides structural support, and the third layer enhances adhesion, collectively improving wet performance while maintaining manufacturing feasibility

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Lignin-based materials are incorporated into the rubber compounds as a composite additive. The lignin-based material (containing carboxyl groups) forms composite structures with the rubber matrix, creating a multi-functional material that provides both the elasticity of rubber and the hydrophilic properties of lignin, thereby improving wet road adhesion without significantly complicating the manufacturing process

Inventive Principle:
Principle #40Composite materials

2Reliability

If the surface rubber layer contains lignin-based material, then hydrophilicity and friction on wet surfaces are enhanced, but the manufacturing precision and control of material distribution become more difficult

Engineering Contradiction:
Improvegrip on wet roadsVSAvoidlignin-based material distribution
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The tread is segmented into multiple layers with progressively decreasing lignin-based material content (first layer: 1-10 parts, second layer: 1-5 parts, third layer: 1-3 parts per 100 parts rubber). This gradient distribution ensures that the surface layer has sufficient lignin for hydrophilicity and wet grip, while inner layers have reduced lignin content for structural stability, making the material distribution controllable and manufacturable

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the tread are assigned different lignin-based material concentrations according to their functional requirements. The outer surface layer (first rubber layer) has the highest lignin content to maximize hydrophilicity and wet road contact, while the inner layers have progressively lower content to maintain structural integrity and reduce manufacturing complexity in those regions

Inventive Principle:
Principle #3Local quality

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 tire achieves improved wet performance by increasing friction and force transmission through hydrogen bonding between the lignin-based materials, leading to better grip and cornering on wet roads.

Implementation Method 1

hydrogen bonding between the lignin-based materials, facilitating the transmission of force

Methodology Applied
Scientific EffectHydrogen bonding: Chemical Bonding

Data Source

PatentEP4538052B1tire
Publication Date: 2026.01.28 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4538052B1 patent drawingFigure 1
  • EP4538052B1 patent drawingFigure 2
  • EP4538052B1 patent drawing

AI summary

Provided is a tire with excellent wet performance. The tire includes a multilayer tread portion including a surface rubber layer and one or more inner rubber layers located inwardly of the surface rubber layer in a tire radial direction, the surface rubber layer and at least one of the one or more inner rubber layers each containing a lignin-based material, an amount Lc (parts by mass) of the lignin-based material per 100 parts by mass of a rubber component in the surface rubber layer being equal to or larger than an amount Lb (parts by mass) of the lignin-based material per 100 parts by mass of a rubber component in the lignin-based material-containing inner rubber layer.