High Strength Rubber Composition Using Aromatic Resins
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Solution Overview
Problem
Conventional rubber compositions used in tires face challenges such as reduced raw aging stability, premature vulcanization, and degradation of mechanical properties due to high sulfur levels, as well as environmental concerns related to formaldehyde production from methylene acceptor/donor systems during vulcanization.
Innovation Solution
A rubber composition incorporating aromatic compounds with hydroxymethyl and aldehyde functions combined with phenolic compounds, which form alternative reinforcing resins that avoid formaldehyde production and maintain rigidity comparable to or exceeding that of compositions using hexa-methylenetetramine or hexamethoxymethylmelamine, while providing improved low deformation and high-temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a concentrated vulcanization system with high sulfur levels is used to achieve high rigidity, then low deformation resistance is improved, but raw aging stability deteriorates due to sulfur migration and flushing
Solution Approach 1:
The patent changes the chemical composition parameters by limiting sulfur to 0.1-5 phr and replacing conventional methylene donors with aromatic compounds containing hydroxymethyl and aldehyde functions. This parameter change maintains rigidity while improving raw aging stability by preventing sulfur migration and flushing during storage
Solution Approach 2:
The patent creates a composite vulcanization system combining aromatic compounds (A1) with phenolic compounds (A2) as a new crosslinking mechanism. This composite approach provides alternative crosslinking pathways that maintain mechanical properties while reducing sulfur content and improving storage stability
2Strength
If a concentrated vulcanization system with high sulfur levels is used to achieve high rigidity, then low deformation resistance is improved, but manufacturing precision deteriorates due to premature vulcanization
Solution Approach 1:
The patent changes the vulcanization kinetics parameters by using aromatic compounds with hydroxymethyl and aldehyde functions that react with phenolic compounds at controlled rates. This provides a longer delay phase and better control over vulcanization timing, preventing premature cooking during tire manufacturing processes
3Strength
If conventional methylene acceptor/donor systems are used to achieve high rigidity, then low deformation resistance is improved, but environmental harm increases due to formaldehyde production
Solution Approach 1:
The patent eliminates the harmful formaldehyde production by replacing conventional methylene acceptor/donor systems with aromatic compounds containing hydroxymethyl and aldehyde functions that react with phenolic compounds. This substitution converts a harmful chemical process into a beneficial one, maintaining rigidity while producing no formaldehyde emissions
Solution Approach 2:
The patent changes the chemical reaction pathway by using aromatic compounds (A1) with hydroxymethyl and aldehyde functions combined with phenolic compounds (A2) instead of conventional methylene acceptors and donors. This parameter change in the vulcanization chemistry eliminates formaldehyde generation while maintaining the reinforcing effect
4Strength
If reinforcing load rate is increased to achieve high rigidity, then low deformation resistance is improved, but rolling resistance increases penalizing hysteresis properties
Solution Approach 1:
The patent changes the reinforcement mechanism by using aromatic compounds (A1) with hydroxymethyl and aldehyde functions combined with phenolic compounds (A2) at lower load rates (0.1-10 phr and 0.1-5 phr respectively). This chemical reinforcement approach provides equivalent rigidity to higher physical reinforcement levels while maintaining better hysteresis and rolling resistance properties
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 achieves equivalent or improved low deformation rigidity compared to conventional compositions, maintains rigidity at elevated temperatures, and eliminates formaldehyde production, addressing environmental concerns and stability issues.
Implementation Method 1
The terms 'methylene acceptor' and 'methylene donor' are well known to those skilled in the art and widely used to designate compounds capable of reacting together to generate by condensation a three-dimensional reinforcing resin which is superimposed and interpenetrates with the reinforcing filler/elastomer network on the one hand and, with the elastomer/sulfur network on the other hand
Implementation Method 2
when the composition is in the form of a semi-finished product, for example a strip of gum, the sulfur can migrate to the surface of the semi-finished product. This phenomenon, called flushing, leads to a reduction in the raw stickiness
Data Source
Figure 1~2
Figure 3
AI summary
The disclosed rubber composition comprises at least one resin that is based on: A1) at least one aromatic compound that contains at least one aromatic ring carrying at least two functions, one of said functions being a hydroxymethyl function, the other one being an aldehyde function or a hydroxymethyl function; and A2) at least one phenol compound selected from among: A21) at least one aromatic polyphenol containing at least one aromatic ring carrying at least two hydroxyl functions in the meta position relative to one another, the two ortho positions of at least one of the hydroxyl functions being unsubstituted; and/or A22) at least one aromatic monophenol containing at least one six-membered aromatic ring carrying a single hydroxyl function, the two ortho positions of the hydroxyl function being unsubstituted, or at least one ortho position and the para position of the hydroxyl function being unsubstituted; and mixtures thereof.