Pre-Vapor Formulation Stability via Antioxidant Intermediaries

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Solution Overview

Problem

Pre-vapor formulations in e-vaping devices face stability issues due to ingredient reactions with metal components, leading to free radical generation and oxidation, which decreases the formulation's stability and affects vapor quality.

Innovation Solution

Incorporating a solvent system that includes propylene glycol, glycerin, saccharide compounds, salt solutions, and polyethylene glycol compounds, which help stabilize the formulation by reducing oxidation and free radical formation, thereby enhancing the stability and quality of the vapor produced.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pre-vapor formulation is stored in contact with metal components (copper, iron) in the cartridge, then the formulation can be delivered through the device, but free radicals are generated through oxidation reactions, decreasing formulation stability

Engineering Contradiction:
Improveformulation stabilityVSAvoidfree radical generation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an intermediary substance (chelating agent or antioxidant) that mediates between the metal components and the pre-vapor formulation. The chelating agent binds to metal ions to form stable complexes, preventing them from participating in oxidation reactions. The antioxidant scavenges free radicals before they can react with formulation ingredients, thus resolving the harmful interaction without eliminating the metal components themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful oxidation process into a beneficial controlled reaction. By adding antioxidants, the uncontrolled free radical generation is transformed into a controlled scavenging process where the antioxidant deliberately reacts with and neutralizes free radicals. The harmful metal-catalyzed oxidation is converted into a protected system where the same metal ions are present but their harmful effects are neutralized by the antioxidant defense mechanism.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Ease of operation

If the wick is not sufficiently supplied with pre-vapor formulation (dry drawing), then the device can still operate, but oxidation reactions increase and free radicals are generated

Engineering Contradiction:
Improvedevice operation flexibilityVSAvoidformulation stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by pre-loading the formulation system with antioxidants and chelating agents before any oxidation can occur. These protective substances are incorporated into the pre-vapor formulation at the manufacturing stage, creating a buffer that will absorb and neutralize free radicals regardless of whether dry drawing occurs. This prior protection ensures that even under suboptimal operating conditions, the formulation remains stable.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent changes the chemical parameters of the formulation by adding substances with specific chemical properties (chelating agents that bind metals, antioxidants that scavenge radicals). These parameter changes transform the formulation from one susceptible to oxidation into one with enhanced chemical stability, allowing the device to operate flexibly without compromising formulation integrity even during dry drawing events.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If heater coil overheats during operation, then vapor generation continues, but metal oxidation accelerates and free radical formation increases

Engineering Contradiction:
Improvevapor generation rateVSAvoidoxidation and free radical formation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces antioxidant intermediaries that act as a buffer between the heated metal coil and the pre-vapor formulation. During overheating events, these antioxidants preferentially react with generated free radicals, preventing them from attacking formulation ingredients. The chelating agents bind metal ions released during thermal stress, preventing catalytic oxidation cycles. This intermediary protection allows high-temperature operation without proportional increases in harmful oxidation products.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 proposed solvent system effectively increases the stability of the pre-vapor formulation, reducing oxidation and free radical reactions, resulting in improved vapor quality and device performance.

Implementation Method 1

ingredients of the pre-vapor formulation may react with the metals of the solid portions of the e-vaping device, such as copper or iron, in the presence of oxygen and generate free radicals

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

The oxidation of pre-vapor formulation ingredients, the cartridge or the container is typically dependent on the presence of oxygen and a redox-active transition metal producing oxygen species such as hydroxyl radicals

Methodology Applied
Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentEP3576552A2Methods and systems for improving stability of pre-vapor formulations of e-vaping devices
Publication Date: 2019.12.11 PHILIP MORRIS PRODUCTS SA

AI summary

A pre-vapor formulation that may be included in an e-vaping device (60) may include a solvent and a solution compound. The solvent may include one or more of propylene glycol and glycerin. The solution compound may include one of a saccharide compound, a salt compound, and a polyethylene compound. The concentration of the solution compound may be between about 0.2 percent and about 10 percent.