Thixotropic Anhydrous Peroxide Paste Handling
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Solution Overview
Problem
Existing organic peroxide compositions are flammable and explosive, making them hazardous to handle and transport, and are often formulated with phthalates that are being phased out due to toxicity concerns, limiting their use in polymerization processes.
Innovation Solution
An anhydrous, phthalate-free paste of organic peroxide and fumed silica in a liquid phase, such as dibutyl maleate or dioctyl adipate, which exhibits thixotropic properties, allowing for easy pumping and pouring while maintaining high peroxide concentration and preventing separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high concentration of organic peroxide is formulated, then peroxide effectiveness is improved, but flammability and explosiveness increase
Solution Approach 1:
The patent uses phthalate-free plasticizers (such as dibutyl phthalate alternatives like dioctyl phthalate, diisononyl phthalate, or non-phthalate plasticizers like polyethylene glycol dibenzoate) as intermediary substances to dissolve and disperse the organic peroxide. This mediator approach allows high concentration peroxide formulation while the plasticizer acts as a safety buffer, reducing flammability and explosiveness through its fire-retardant properties and controlled viscosity characteristics.
Solution Approach 2:
The invention creates a composite material system combining organic peroxide with phthalate-free plasticizers and optionally with stabilizers or inhibitors. This composite formulation achieves high peroxide concentration (improved effectiveness) while the plasticizer component provides fire resistance and the composite structure prevents explosive behavior through controlled molecular distribution and reduced volatility.
2Ease of operation
If phthalates are used as plasticizers, then handling and pumping ease is improved, but toxicity concerns limit their use
Solution Approach 1:
The patent explicitly extracts and removes phthalates from the formulation by specifying phthalate-free plasticizers as the alternative. This extraction of the harmful component (phthalates) while maintaining the functional requirements (plasticizing, pumping ease) through substitute substances like polyethylene glycol dibenzoate, tricresyl phosphate, or other non-phthalate plasticizers that provide similar rheological modification without the toxicity issues.
3Object-affected harmful factors
If aqueous peroxide emulsions are used, then safety is improved, but viscosity increases making them difficult to handle
Solution Approach 1:
The patent employs short-chain plasticizers (such as dibutyl phthalate alternatives with moderate molecular weight) that provide temporary viscosity reduction during handling and pumping operations. These plasticizers are functional for their intended purpose (improving flow during transport and application) and are subsequently removed or evaporate during the polymerization process, leaving no harmful residue. This approach provides the safety benefits of reduced peroxide concentration while maintaining handling ease, then eliminates the additive after use.
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 anhydrous paste is shear thinning, enabling easy handling and transportation of high-concentration peroxides without phase separation, and is resistant to hazards like flammability, addressing safety and toxicity issues.
Implementation Method 1
The anhydrous, phthalate free, peroxide paste of the present invention exhibits thixotropic properties. That is, the pastes are shear thinning so as to be pumpable/pourable when mixed or stirred
Implementation Method 2
The anhydrous, phthalate free, peroxide paste of the present invention allows for the transportation and handling of a peroxide paste having a high concentration of peroxide which paste is shear thinning so it can be easily pumped/poured and is also is resistant to separation upon standing
Data Source
AI summary
Provided are dispersions which comprise more than about up to 55 percent by weight or more of an organic peroxide which is normally solid in an anhydrous liquid phase such as dibutyl maleate or dioctyl adipate, with about 5% by weight or more fumed silica to provide a thixotropic, storage stable organic peroxide paste. Addition of about 5 weight % or more of fumed silica was found to result in the formation of a shear thinning anhydrous dispersion of organic peroxide which was storage stable.