Non-Flammable Aerosol Duster Propellant via Azeotropic HFO Blend
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Solution Overview
Problem
Aerosol dusters face challenges with flammability and environmental impact due to the use of HFC-134a, which is a potent global warming agent, and its replacement HFC-152a, which is slightly flammable and produces toxic byproducts, necessitating the development of a totally non-flammable and environmentally friendly propellant.
Innovation Solution
A composition of 78% HFO-1234ze(E) and 22% HFO-1336mzz forms an azeotropic solution, maintaining total non-flammability and effective spray characteristics, with HFO-1234ze(E) being slightly flammable at temperatures above 26 C, but becoming non-flammable when mixed with HFO-1336mzz, which is added in sufficient quantities to eliminate flammability risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HFC-134a is used as propellant, then total non-flammability is achieved, but global warming potential increases significantly
Solution Approach 1:
The patent changes the chemical composition parameters by transitioning from HFC-134a to HFO-1234ze(E) as the primary propellant, and formulates a specific composition range (60-90% HFO-1234ze(E) with 10-40% HFO-1336mzz) to achieve both non-flammability and environmental compatibility. This parameter change resolves the contradiction by selecting chemicals with fundamentally different environmental properties.
Solution Approach 2:
The patent creates a composite propellant system by combining HFO-1234ze(E) and HFO-1336mzz in specific proportions. This composite approach allows the mixture to exhibit non-flammability (achieved at approximately 20% HFO-1336mzz or higher) while maintaining low global warming potential, thus resolving the contradiction between safety and environmental impact.
2Object-affected harmful factors
If HFO-1234ze(E) is used as propellant, then global warming potential is reduced, but flammability increases at temperatures above 26 C
Solution Approach 1:
The patent introduces HFO-1336mzz as an intermediary substance that modifies the flammability characteristics of HFO-1234ze(E). By combining these two HFO compounds in specific ratios (approximately 20% or more HFO-1336mzz), the mixture achieves non-flammability while maintaining the low global warming potential of the HFO chemistry, thus resolving the flammability concern of pure HFO-1234ze(E).
Solution Approach 2:
The patent changes the compositional parameters by formulating a specific range of HFO-1234ze(E) and HFO-1336mzz ratios. The critical parameter is maintaining HFO-1336mzz at approximately 20% or higher in the mixture, which shifts the flammability characteristics from flammable (pure HFO-1234ze(E)) to non-flammable (mixture), while preserving environmental benefits.
3Reliability
If HCFC-22 and HCFC-142b blend is used, then total non-flammability is maintained, but HCFC-22 depletion leads to flammable vapor enrichment
Solution Approach 1:
The patent achieves compositional homogeneity in the vapor phase by using an azeotropic or near-azeotropic mixture of HFO-1234ze(E) and HFO-1336mzz. This ensures that the vapor discharged from the aerosol can maintains the same composition ratio as the liquid propellant throughout the product's lifecycle, preventing the flammable enrichment problem that occurred with HCFC blends where the more volatile component depleted first.
4Reliability
If HFO-1336mzz is added to eliminate flammability, then non-flammability is achieved, but internal pressure may exceed DOT regulations
Solution Approach 1:
The patent carefully controls the concentration parameter of HFO-1336mzz within the range of 10-40%, with the critical threshold at approximately 20% for achieving non-flammability. By optimizing this parameter, the formulation achieves the minimum necessary amount of HFO-1336mzz to eliminate flammability while keeping the total pressure increase within acceptable limits that comply with DOT transportation regulations.
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 azeotropic mixture of HFO-1234ze(E) and HFO-1336mzz ensures the aerosol duster remains totally non-flammable under all foreseeable conditions, reducing the risk of fires and environmental harm, while maintaining spray efficacy and pressure within safe limits, thus addressing the limitations of previous propellants.
Implementation Method 1
A composition of about 78% HFO-1234ze(E) and 22% HFO-1336mzz forms an azeotropic solution, maintaining total non-flammability and effective spray characteristics
Data Source
AI summary
A composition of matter for the self-pressurized (aerosol) spraying of dusters and similar products. The composition includes a fluorinated propene-based propellant and fluorinated butene-based volatile solvent. The composition is totally non-flammable under all reasonably foreseeable conditions of use. The fluorinated propene-based propellant may include trans-1,3,3,3-tetrafluoroprop-1-ene, as typified by Honeywell Fluorine Products Division's SOLSTICE® HFO-1234ze(E) product. The fluorinated butene-based volatile solvent may include cis. (or cis./trans.) 1,1,1,4,4,4-hexafluoro-2-butene, as typified by the DuPont Fluorochemicals Division's FORMACEL® 1100 (HFO-1336mzz) product. The fluorinated propene-based propellant component may be present at about 60 to 95%. The fluorinated butene-based volatile solvent component may be present at about 5% to 40%, but preferably between about 20% to 25% and ideally at about the azeotropic concentration of about 22%. Some or all of the fluorinated butene based component may be replaced with up to about 25% of a totally non-flammable component, such as iodotrifluoromethane (CIF.sub.3).