High-rigidity rubber composition using phenol-aldehyde resin
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Solution Overview
Problem
Conventional rubber compositions used in tires, which achieve high stiffness through methylene acceptor and donor systems, produce formaldehyde and require additional resins like bisphenol A, leading to retention issues in compounding devices and delayed crosslinking.
Innovation Solution
A rubber composition utilizing a phenol/aldehyde resin based on aromatic polyphenols and aromatic polyaldehydes, such as 1,3-benzenedicarboxaldehyde, which maintains high stiffness without formaldehyde production and avoids the need for additional reinforcing resins like bisphenol A, ensuring easy processing and high-temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional methylene acceptor and donor systems are used to achieve high stiffness, then the secant modulus is improved, but formaldehyde is generated causing environmental harm
Solution Approach 1:
The patent changes the chemical parameters of the crosslinking system by replacing conventional methylene acceptors and donors with alternative compounds that do not generate formaldehyde, while maintaining the crosslinking functionality and achieving the required stiffness through different chemical mechanisms
Solution Approach 2:
The patent eliminates the harmful formaldehyde generation by using alternative crosslinking chemistry, converting a harmful process into a beneficial one by achieving the same technical effect (stiffness) without the adverse environmental impact
2Reliability
If pre-condensed phenolic resin is used as methylene acceptor, then crosslinking is achieved, but retention in internal mixer occurs due to tack
Solution Approach 1:
The patent extracts the problematic tack property from the crosslinking system by replacing pre-condensed phenolic resin with alternative methylene acceptors that do not exhibit excessive tack, thereby eliminating retention issues while preserving crosslinking functionality
Solution Approach 2:
The patent introduces alternative methylene acceptor compounds as intermediaries that facilitate crosslinking without the adverse tack property, acting as a mediator between the requirement for crosslinking and the need to avoid retention in mixing equipment
3Ease of operation
If bisphenol A is added to reduce tack, then retention is reduced, but crosslinking is delayed
Solution Approach 1:
The patent eliminates the need to add bisphenol A by using alternative methylene acceptors that inherently provide low tack without delaying crosslinking, converting a situation that required a compromising additive into one where the base system itself provides the desired properties
4Ease of operation
If additional reinforcing resin like bisphenol A is used to reduce retention, then processing is improved, but device complexity increases
Solution Approach 1:
The patent extracts the problematic need for additional reinforcing resins by selecting methylene acceptors that provide both low tack and adequate crosslinking functionality, thereby simplifying the overall composition while maintaining ease of processing
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 composition achieves a secant modulus of at least 25 MPa at 10% elongation, maintaining stiffness up to 150°C without retention issues in compounding devices and without generating formaldehyde, thus addressing environmental concerns and processing challenges.
Implementation Method 1
The terms 'methylene acceptor' and 'methylene donor' are well known to those skilled in the art and are widely used to denote compounds capable of reacting together to generate, by condensation, a three-dimensional reinforcing resin
Data Source
AI summary
A rubber composition comprises at least one phenol/aldehyde resin based on at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functions in the meta position relative to one another, the two positions ortho to at least one of the hydroxyl functions being unsubstituted, and at least one aromatic polyaldehyde selected from 1,3-benzenedicarboxaldehyde, 1,4-benzenedicarboxaldehyde and mixtures of these compounds, the rubber composition having a nominal secant modulus at 10% elongation, measured according to standard ASTM D 412, 1998, of greater than or equal to 25 MPa.