Cigarette Outer Wrapper Composite for Heat Transfer and Strength

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Solution Overview

Problem

Traditional cigarettes are prone to damage and have reduced heat transfer efficiency when used in externally heated aerosol-generating devices, leading to strength issues and inefficient aerosol production.

Innovation Solution

A cigarette design featuring an outer wrapper with a basis weight of 57 g/m² to 63 g/m² and thickness of 64 µm to 70 µm, along with a second wrapper with higher porosity and a coating material like sodium-citrate or potassium-citrate to enhance heat transfer and tensile strength, ensuring effective aerosol generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the outer wrapper uses a thicker and heavier material to increase cigarette strength, then the cigarette becomes more resistant to damage and cutting, but the heat transfer efficiency from the external heat source to the cigarette interior decreases

Engineering Contradiction:
Improvecigarette strengthVSAvoidheat transfer efficiency
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The outer wrapper is constructed as a composite material combining high-strength polymer fibers (such as polyethylene terephthalate or polypropylene) with heat-conductive additives (such as aluminum powder, aluminum foil, or metal oxides). This composite structure enables the wrapper to simultaneously achieve high tensile strength for damage resistance and improved thermal conductivity for efficient heat transfer to the cigarette interior

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameters of the outer wrapper including thickness (0.03mm to 0.08mm), basis weight (20 g/m² to 80 g/m²), and fiber diameter (1 denier to 10 denier) to balance mechanical strength and heat transfer properties. By precisely controlling these parameters, the wrapper achieves sufficient strength while maintaining adequate thermal conductivity for aerosol generation

Inventive Principle:
Principle #35Parameter changes

2Strength

If the outer wrapper absorbs more heat during transfer, then the cigarette structure is protected, but the rate of heat transfer to the inside of the cigarette decreases, preventing smooth aerosol generation

Engineering Contradiction:
Improvestructural integrityVSAvoidaerosol generation efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The outer wrapper incorporates porous structures with controlled porosity (30% to 70%) that allow heat to pass through while providing structural framework for strength. The porous architecture reduces heat absorption by the wrapper material itself while maintaining mechanical integrity, enabling efficient heat transfer to the aerosol-generating material inside

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent adjusts the porosity, thickness, and density parameters of the outer wrapper to optimize the balance between structural protection and heat transfer. By controlling these parameters, the wrapper minimizes heat absorption while maintaining sufficient strength, ensuring adequate heat reaches the interior for smooth aerosol generation

Inventive Principle:
Principle #35Parameter changes

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 enhanced wrapper structure increases the cigarette's strength and heat transfer efficiency, preventing damage and ensuring smooth aerosol production when used in aerosol-generating devices.

Implementation Method 1

a coating material applied to at least one of an inner and an outer surface of the second wrapper such that a heat transfer rate for the heat transferred to the cigarette rod through the second wrapper is improved

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3818875B1Cigarette with outer wrapper
Publication Date: 2024.09.18 KT&G CO LTD
  • EP3818875B1 patent drawingFigure 1
  • EP3818875B1 patent drawingFigure 2
  • EP3818875B1 patent drawingFigure 3

AI summary

A cigarette according to an embodiment may include a cigarette rod including an aerosol-generating material; a filter rod located at one end of the cigarette rod and including a first segment and a second segment; a front end plug located at the other end of the cigarette rod; and an outer wrapper wrapping the cigarette rod, the filter rod and the front end plug, wherein the outer wrapper has a basis weight of 57 g/m2 to 63 g/m2 and a thickness of 64 µm to 70 µm to increase the strength of the cigarette.