Combustible Heat Source with Ignition Aid and Wrapper

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Solution Overview

Problem

Existing combustible heat sources for heated smoking articles often fail to generate enough heat for early puffs while avoiding combustion or thermal degradation of aerosol-forming materials, and are difficult to ignite with conventional lighters.

Innovation Solution

A combustible heat source comprising carbon and at least one ignition aid, where the ignition aid is present in an amount of at least 20% by dry weight, featuring a two-stage combustion process with a 'boost' in temperature followed by sustained combustion at a lower temperature, facilitated by a combustion-resistant wrapper that is both heat-conducting and oxygen-impermeable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the combustion temperature of the combustible heat source is increased to generate enough heat for early puffs, then the aerosol production during early puffs is improved, but the aerosol-forming material undergoes combustion or thermal degradation

Engineering Contradiction:
Improveheat generation capacityVSAvoidthermal degradation of aerosol-forming material
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The patent implements a two-stage combustion process where the combustible heat source undergoes an initial high-temperature combustion phase to rapidly generate heat for early puffs, followed by a transition to a lower temperature sustained combustion phase. This periodic variation in combustion intensity allows the system to achieve both rapid heat generation and protection of the aerosol-forming material from excessive thermal exposure

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The combustible heat source is designed with properties that enable it to rapidly reach high temperature upon initial ignition, providing the necessary heat boost before the aerosol-forming material is fully exposed. This preliminary high-temperature phase establishes the thermal conditions needed for acceptable early puff aerosol production before transitioning to a controlled lower temperature regime

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If the combustion temperature is kept low to avoid thermal degradation of aerosol-forming material, then the material stability is improved, but insufficient heat is generated to produce acceptable aerosol during early puffs

Engineering Contradiction:
Improveavoidance of thermal degradationVSAvoidheat generation for early puffs
Core Design Contradiction:
Object-affected harmful factorsVSPower

Solution Approach 1:

The combustion process is structured to exhibit periodic behavior with distinct phases: an initial high-temperature phase that provides sufficient heat for early puff aerosol generation, followed by a transition to a lower temperature phase that maintains material stability. This temporal separation of temperature regimes resolves the contradiction between needing high heat and avoiding thermal degradation

Inventive Principle:
Principle #19Periodic action

3Device complexity

If conventional carbon-based heat sources are used to maintain simplicity, then the device complexity is reduced, but the ignition difficulty with conventional lighters increases

Engineering Contradiction:
Improveheat source structureVSAvoidignition ease
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent modifies the chemical composition parameters of the combustible heat source by incorporating specific oxidizing agents and additives in controlled amounts. These parameter changes enhance the ignition characteristics of the carbon-based material, enabling reliable ignition with conventional lighters while maintaining the overall simplicity of the heat source structure

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If small amounts of oxidizing agents are added to improve ignition properties, then the ignition ease is improved, but the heat generation capacity remains insufficient for early puffs

Engineering Contradiction:
Improveignition easeVSAvoidheat generation capacity
Core Design Contradiction:
Ease of operationVSPower

Solution Approach 1:

The patent optimizes the concentration parameters of oxidizing agents and other additives within specific ranges that simultaneously improve ignition characteristics and enhance heat generation capacity. By carefully adjusting these compositional parameters, the heat source achieves both easy ignition and sufficient thermal output for early puff aerosol production

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The combustible heat source is formulated as a composite material system combining carbon-based material with specific oxidizing agents and additives. This composite structure synergistically combines the combustion properties of carbon with the oxygen-release characteristics of the oxidizing agents, achieving both improved ignition and enhanced heat generation capacity

Inventive Principle:
Principle #40Composite materials

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

Ensures rapid ignition and generation of an acceptable aerosol during early puffs without thermal degradation of the aerosol-forming material, using a conventional yellow flame lighter, by controlling the temperature profile of the heat source.

Implementation Method 1

a combustion resistant wrapper that is one or both of heat conducting and substantially oxygen impermeable

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

a combustion resistant wrapper that is one or both of heat conducting and substantially oxygen impermeable

Methodology Applied
Scientific EffectOxygen impermeability: Permeation

Implementation Method 3

combustible heat source comprising carbon and at least one ignition aid

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 4

upon ignition of the first portion of the combustible heat source the second portion of the combustible heat source increases in temperature

Methodology Applied
Scientific EffectExothermic reaction: Exothermic Reaction

Data Source

PatentEP3533347A1Combustible heat source for a smoking article
Publication Date: 2019.09.04 PHILIP MORRIS PRODUCTS SA
  • EP3533347A1 patent drawingFigure 1~2a
  • EP3533347A1 patent drawingFigure 2b~3a
  • EP3533347A1 patent drawingFigure 3b~4a

AI summary

A combustible heat source (4) for a smoking article (2) comprises carbon and at least one ignition aid, wherein the ignition aid is present in an amount of at least 20 percent by dry weight of the combustible heat source. The combustible heat source (4) has a first portion and an opposed second portion. At least part (4b) of the combustible heat source (4) between the first portion and the second portion is wrapped in a combustion resistant wrapper (22) that is one or both of heat conducting and substantially oxygen impermeable. Upon ignition of the first portion of the combustible heat source (4), the second portion of the combustible heat source increases in temperature to a first temperature. During subsequent combustion of the combustible heat source (4), the second portion of the combustible heat source (4) maintains a second temperature lower than the first temperature.