Functionalized Polyamide Tire Cord Adhesion via Thiol Crosslinking

Solution Overview

Problem

The existing process of using polyamide fiber cords in tires requires a dip treating step with adhesive solutions, which increases costs and manufacturing time, and there is a need to reduce or eliminate this step for weight reduction and improved productivity.

Innovation Solution

Functionalized polyamides with terminal free thiols are reacted with amide monomers or mixtures of diamines and dicarboxylic acids to crosslink directly with rubber, eliminating the need for additional adhesives in the tire cord preparation process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If adhesive solution dip treating step is used, then adhesion between fiber and rubber is improved, but manufacturing cost and time increase

Engineering Contradiction:

Improveadhesion between fiber and rubberVSAvoidmanufacturing time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The polyamide fiber is pre-functionalized with thiol groups during the polymerization process before tire manufacturing. This preliminary introduction of reactive functional groups eliminates the need for subsequent dip treating steps, reducing manufacturing time while maintaining adhesion strength.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention extracts and eliminates the separate dip treating step from the manufacturing process by integrating the adhesion-promoting functionality directly into the polyamide fiber structure through thiol group incorporation during polymerization.

Inventive Principle:

Principle #2Taking out (Extraction)

2Strength

If adhesive solution dip treating step is used, then adhesion between fiber and rubber is improved, but manufacturing cost increases

Engineering Contradiction:

Improveadhesion between fiber and rubberVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The polyamide fiber is pre-functionalized with thiol groups during the polymerization process before tire manufacturing. This preliminary introduction of reactive functional groups eliminates the need for subsequent dip treating steps, reducing manufacturing cost while maintaining adhesion strength.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention extracts and eliminates the separate dip treating step from the manufacturing process by integrating the adhesion-promoting functionality directly into the polyamide fiber structure through thiol group incorporation during polymerization.

Inventive Principle:

Principle #2Taking out (Extraction)

3Strength

If adhesive material is used, then adhesion between fiber and rubber is improved, but tire weight increases

Engineering Contradiction:

Improveadhesion between fiber and rubberVSAvoidtire weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The invention removes the additional adhesive material layer from the tire structure by incorporating adhesion-promoting thiol groups directly into the polyamide fiber, eliminating unnecessary weight while maintaining bonding strength.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The polyamide fiber serves multiple functions simultaneously: it provides structural reinforcement and contains built-in adhesion functionality through thiol groups, eliminating the need for separate adhesive materials.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This method reduces or eliminates the dip treating step, leading to cost savings, weight reduction, and improved productivity by enabling direct adhesion of polyamide fibers to rubber without additional adhesive materials.

Implementation Method 1

reacting at least one thio acid with (i) an amide monomer or (ii) a mixture of a diamine and a dicarboxylic acid

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

functionalized polyamides can be used in tire cords that include terminal free thiols to crosslink directly with rubber

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Data Source

PatentUS10767012B2Functionalized polyamides and methods of preparing the same

Publication Date: 2020.09.08 FIRESTONE FIBERS & TEXTILES CO LLC

AI summary

A functionalized polyamide is prepared by reacting a thio acid with an amide monomer or a mixture of a diamine and a dicarboxylic acid. In the reaction, the amide monomer is preferably a lactam compound, the thio acid has a formula of HOOC-A-SH wherein A represents an alkylene group containing from 1 to 10 carbon atoms, the diamine is an aliphatic diamine and the dicarboxylic acid is a aliphatic dicarboxylic acid. The functionalized polyamide can be vulcanized directly with rubber, which results in the use of less dip for adhering the tire cord to the rubber.