Pre-vulcanized Tread Strip Assembly with Superabsorbent Polymer Film

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Solution Overview

Problem

The use of water-based adhesive mixtures in pre-vulcanized tread strip assemblies for cold retreading is complicated by the presence of water, which interferes with vulcanization and leads to weak adhesion between the protective polymer film and the adhesive mixture, causing contamination and reduced effectiveness, while organic solvent-based solutions are environmentally restricted.

Innovation Solution

A pre-vulcanized tread strip assembly featuring a water-based adhesive mixture covered with a protective polymer film comprising superabsorbent polymers, which absorbs and retains water, maintaining adhesion during storage and ensuring dryness for effective retreading, using a polyethylene-based film with sodium polyacrylate, optimizing protection and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If water-based adhesive mixture is used, then environmental impact is reduced, but adhesion between protective film and adhesive mixture becomes weak

Engineering Contradiction:
Improveenvironmental impactVSAvoidadhesion between protective film and adhesive mixture
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

A polyethylene-based protective film containing superabsorbent polymer particles (sodium polyacrylate) acts as an intermediary between the water-based adhesive mixture and the external environment. The superabsorbent polymer serves as a mediator that selectively absorbs excess water while preserving the adhesive properties, enabling both environmental compatibility and strong adhesion.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective film changes the water content parameter of the adhesive mixture by absorbing excess water through superabsorbent polymer particles. This parameter change maintains the necessary water content for adhesion while removing excess water that would otherwise prevent proper bonding and cause contamination.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If water-based adhesive mixture is used, then environmental impact is reduced, but contamination risk increases

Engineering Contradiction:
Improveenvironmental impactVSAvoidadhesive mixture effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The polyethylene-based protective film with superabsorbent polymer particles serves as a protective intermediary that shields the water-based adhesive mixture from contamination during storage. By absorbing excess water and preventing external contaminants from reaching the adhesive, the film maintains the reliability and effectiveness of the adhesive mixture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective film provides beforehand cushioning by pre-absorbing excess water and preventing contamination before the adhesive mixture is applied to the tyre carcass. This prior protection ensures the adhesive maintains its effectiveness throughout storage and handling.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If protective film is applied over wet adhesive mixture, then adhesion during storage is improved, but vulcanization is interfered with

Engineering Contradiction:
Improveadhesion during storageVSAvoidvulcanization process
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The superabsorbent polymer particles in the protective film selectively change the water content parameter of the adhesive mixture by absorbing excess water. This creates an optimal balance where sufficient water remains for adhesion during storage, but excess water that would interfere with vulcanization is removed.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The protective film creates local quality differences within the adhesive mixture by absorbing water in specific areas while leaving other areas with sufficient moisture for adhesion. This localized water management enables both good storage adhesion and proper vulcanization.

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 solution allows for effective adhesion between the tread strip and the carcass without additional time or energy, maintaining the water-based adhesive mixture's integrity and ensuring correct adhesion during retreading, while reducing environmental impact.

Implementation Method 1

a protective polymer film comprising superabsorbent polymers, which absorbs and retains water

Methodology Applied
Scientific EffectSuperabsorbent polymer absorption: Absorption (physical)

Implementation Method 2

maintaining the water-based adhesive mixture's integrity and ensuring correct adhesion during retreading

Methodology Applied
Scientific EffectHydrogel water retention: Hydrogel

Data Source

PatentEP3072673B1Pre-vulcanized tread strip assembly useful for the cold retreading of a tyre
Publication Date: 2018.02.07 BRIDGESTONE CORP

AI summary

A pre-vulcanized tread strip assembly useful for the cold retreading of a tyre and comprising a pre-vulcanized tread strip, an adhesive mixture layer arranged on said pre-vulcanized tread strip and a protective polymer film layer arranged so as to cover the adhesive mixture layer; said tread strip assembly being characterized in that said adhesive mixture is water-based and said protective polymer film is made of a polymer composition comprising at least a compound which is comprised in the class of superabsorbent polymers.