Water-Based Polyurethane Predip for Carbon Fiber Cord Adhesion
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Solution Overview
Problem
Conventional power transmission belts face challenges in achieving high adhesion between reinforcing cords and rubber compounds under severe conditions of high loads, high tensions, and high temperatures, while requiring complex and environmentally unfriendly treatment processes.
Innovation Solution
A three-dip process using a water-based polyurethane emulsion stabilized with internal anionic and external nonionic species, followed by a resorcinol-formaldehyde-latex (RFL) suspension and a rubber-based overcoat, to treat carbon fiber cords, enhancing tensile strength, fiber cohesion, and flex fatigue resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional three-coating treatment (isocyanate/epoxy primer, RFL treatment, and complex overcoat adhesive) is used, then adhesion between cords and rubber is achieved, but process complexity and environmental harm increase
Solution Approach 1:
The patent combines the primer and overcoat adhesive functions into a single water-based polyurethane coating that provides both adhesion to carbon fibers and compatibility with rubber compounds. This eliminates the need for separate primer and overcoat layers, reducing the treatment process from three complex coatings to a single integrated coating that maintains reliable adhesion while simplifying the manufacturing process
Solution Approach 2:
The patent changes the chemical composition parameters by using water-based polyurethane instead of organic solvent-based isocyanate/epoxy systems. This parameter change eliminates the need for complex environmental controls and safety measures associated with organic solvents, thereby reducing process complexity while maintaining adhesion performance
2Reliability
If conventional organic solvent-based primer and complex overcoat adhesive are used, then adhesion is achieved, but environmental friendliness deteriorates
Solution Approach 1:
The patent fundamentally changes the solvent parameter from organic solvents (isocyanate/epoxy in organic solvent) to water as the base for the polyurethane emulsion. This parameter change eliminates volatile organic compound (VOC) emissions and reduces environmental harm while maintaining the adhesion functionality through the water-based polyurethane system that provides both fiber bonding and rubber compatibility
Solution Approach 2:
The patent converts the traditionally harmful organic solvent system into a beneficial water-based system. By using water as the dispersion medium instead of organic solvents, the process transforms an environmentally harmful practice into an eco-friendly solution that reduces air pollution and health hazards while achieving the same adhesion objectives
3Reliability
If complex multi-component adhesive system is used, then adhesion under severe conditions is achieved, but manufacturing cost increases
Solution Approach 1:
The patent merges multiple adhesive functions (primer adhesion to fibers, overcoat adhesion to rubber, and intermediate bonding) into a single water-based polyurethane coating system. This consolidated approach reduces the adhesive system from multiple complex components requiring separate application and optimization to one integrated coating that provides comprehensive adhesion under severe operating conditions including high loads, tensions, and temperatures
Solution Approach 2:
The water-based polyurethane coating exhibits multi-functionality by simultaneously providing: (1) adhesion to carbon fiber cords, (2) compatibility with rubber compounds, (3) resistance to high loads and tensions, and (4) thermal stability. This universal coating eliminates the need for multiple specialized adhesive layers, reducing system complexity while maintaining performance under severe conditions
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 method improves tensile strength by up to 30%, enhances fiber-to-fiber cohesion, and increases flex fatigue resistance, while reducing process complexity and environmental impact.
Implementation Method 1
a water based polyurethane emulsion stabilized with internal anionic and external nonionic species
Implementation Method 2
enhancing tensile strength, fiber cohesion, and flex fatigue resistance
Implementation Method 3
a resorcinol-formaldehyde-latex (RFL) suspension
Implementation Method 4
a rubber based overcoat
Data Source
Figure 1~3
Figure 4~5
AI summary
The invention relates to a method comprising: providing a plurality of cords (106) dipping the plurality of cords a first tank comprising a polyurethane emulsion stabilized with internal anionic and external nonionic species, dipping the plurality of cords a second tank comprising RFL suspension, and dipping the plurality of cords a third tank comprising rubber based polymer, to provide a plurality of treated cords; providing a first elastomeric layer; laying up the plurality of treated cords (106) on the first elastomeric layer to form tensile reinforcement layer; laying up a second elastomeric layer on the tensile reinforcement layer; and, curing the combination of the first elastomeric layer, the tensile reinforcement layer and the second elastomeric layer in a profile fomring mold. Methods of manufacturing a belt are also disclosed.