Antioxidant Precursor for Rubber Composition
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Solution Overview
Problem
The poor solubility and rapid migration of antioxidants in rubber compositions limit their effectiveness in preventing oxygen and ozone degradation, necessitating a balance in antioxidant behavior to enhance the resistance of rubber goods.
Innovation Solution
The development of an antioxidant precursor compound that forms a modified polymer with an antioxidant functional group, allowing for controlled release of hindered phenols within the rubber composition, thereby improving resistance to crack growth and maintaining other properties like tear strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antioxidants are introduced into rubber stock to protect from oxygen degradation, then antioxidant effectiveness is improved, but solubility limitations restrict the amount that can be introduced
Solution Approach 1:
The patent uses silane-modified polymers as intermediary carriers to deliver antioxidant compounds into the rubber stock. The silane group enables covalent bonding to the polymer matrix, while the antioxidant functional group provides protective activity. This intermediary approach overcomes direct solubility limitations by using a bifunctional molecule that bridges the polymer and antioxidant.
Solution Approach 2:
The invention creates a composite structure where antioxidant compounds are chemically integrated with silane-modified polymer chains. This composite approach allows the antioxidant to be part of the polymer matrix itself, achieving high effective concentration without relying on simple dissolution, thus bypassing solubility constraints.
2Speed
If antioxidants migrate quickly to the surface of the material, then antioxidant distribution is improved, but effectiveness becomes short-lived
Solution Approach 1:
The antioxidant is pre-bound to the silane-modified polymer through covalent bonding before processing. This preliminary attachment prevents uncontrolled rapid migration to the surface. The antioxidant is released in a controlled manner as the polymer degrades or the silane bonds break, providing sustained protection over time rather than quick surface migration followed by depletion.
Solution Approach 2:
The invention changes the chemical state of the antioxidant from free-moving to polymer-bound through silane modification. This parameter change in molecular mobility transforms the antioxidant's behavior from rapid surface migration to controlled, sustained release, extending its effective duration while maintaining protective function.
3Stability of the object's composition
If antioxidants are bound to polymer chains, then migration control is improved, but solubility in rubber stock may be affected
Solution Approach 1:
The invention extracts the problematic solubility issue by separating the antioxidant delivery function from direct dissolution. Instead of relying on antioxidant solubility in rubber, the system uses silane-modified polymers that carry the antioxidant as a pendant group. The antioxidant is effectively 'taken out' of the solubility constraint and delivered through the polymer carrier.
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 antioxidant precursor compound effectively migrates throughout the rubber composition upon hydrolysis, providing improved resistance to oxygen and ozone deterioration while maintaining tear strength and other properties.
Implementation Method 1
The antioxidant precursor can be bound to an unsaturated polymer to form a modified polymer having an antioxidant precursor functional group. The modified polymer can be incorporated into a rubber composition, and upon hydrolysis of the antioxidant precursor functional group, an antioxidant compound is released.
Data Source
AI summary
An antioxidant precursor compound represented by the formulawhere R2 through R6 are each independently a hydrogen atom or a monovalent organic group, R7 and R8 are each independently a monovalent organic group, R9 is a hydrogen atom or a blocking group, and R10 is a covalent bond or a divalent organic group, with the proviso that at least one of R2 and R6 are sterically bulky groups.