Epoxide-Functionalized Novolak Resin Composition for Tyre Crown Reinforcements
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Solution Overview
Problem
Existing thermosetting resin compositions for tyre crown reinforcements face challenges in achieving a balance between processability, stiffness, and storage stability, particularly in maintaining low crosslinking rates at ambient temperatures, which affects the integrity and shape retention of fibrous reinforcers under stress.
Innovation Solution
A composition of epoxide-functionalized novolac resins, combining specific aromatic polyphenols and aldehyde functions, with phenolic or amine-type curing agents, offering a molar mass range of 550-650 g/mol and epoxide functionality of 3-3.5 eq/mol, providing a glass transition temperature of at least 160°C and allowing for stable storage and impregnation of fibrous reinforcers without the need for solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If epoxy resin compositions are used for tyre crown reinforcements, then high stiffness and shape retention are achieved, but crosslinking begins immediately upon contact with curing agents, causing viscosity to increase gradually and limiting storage time
Solution Approach 1:
The curing agent is dissolved in a solvent beforehand to create a pre-mixed composition that is ready for immediate use. This preliminary preparation eliminates the need for separate mixing of resin and curing agent, allowing the composition to be stored for extended periods without significant crosslinking while maintaining low viscosity during storage and application
2Ease of manufacture
If the curing agent is solid at ambient temperature, then effective mixing requires dissolving the curing agent in a solvent or heating the composition, but this increases crosslinking rate and viscosity
Solution Approach 1:
A solvent is introduced as an intermediary substance to dissolve the solid curing agent, enabling homogeneous mixing at ambient temperature without heating. The solvent acts as a medium that facilitates the dissolution and distribution of the curing agent throughout the resin, ensuring effective mixing while controlling the crosslinking rate and viscosity during storage and application
3Ease of operation
If the composition is heated to increase mixing effectiveness, then crosslinking rate increases and viscosity rises, but this reduces storage stability and open time
Solution Approach 1:
The use of a solvent allows the composition to be maintained at ambient temperature during storage and mixing, changing the physical state parameters to prevent premature crosslinking. The solvent modifies the viscosity and reactivity parameters, enabling effective mixing without heating while maintaining storage stability and extending the open time of the composition
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 provides enhanced processability and stiffness, enabling the composition to maintain its properties over extended storage periods and during curing, ensuring the integrity and performance of tyre crown reinforcements.
Implementation Method 1
crosslinking begins as soon as the resin and the curing agent are contacted
Implementation Method 2
the composition comprising the fibrous reinforcers making up these strips must have a glass transition temperature, Tg, which is sufficiently high—at least 160° C.—for the strip to withstand the stages of adhesive coating and curing
Implementation Method 3
the composition must—before curing—have a viscosity which is sufficiently low for proper impregnation of the fibrous reinforcer
Data Source
AI summary
A composition of epoxide-functionalized resins comprises at least a first epoxide-functionalized novolac resin, a second epoxide-functionalized novolac resin, and a curing agent selected from phenolic or amine-type curing agents, the average molar mass of the group consisting of the entirety of the epoxidized novolac resins in the said composition being between 550 and 650 g/mol, the average epoxide functionality of the said group being between 3 and 3.5 eq epoxide/mol, and the said composition having a glass transition temperature Tg of at least 160° C.