Phase Transition Material Coating for Cigarette Ignition Propensity

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Solution Overview

Problem

Existing smoking articles can ignite fire-prone substrates due to their ignition propensity, and current methods to reduce this propensity, such as starch-based coatings, are costly, limited to off-line implementation, and affect user experience.

Innovation Solution

Application of phase transition materials (PTMs) like paraffin, carnauba, and beeswax in a uniform, non-continuous layer on cigarette paper, which transitions from solid to liquid at burning temperatures, forming a dynamic, low-permeability band to reduce oxygen supply and prevent ignition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If starch-based coatings are applied to reduce ignition propensity, then ignition propensity is reduced, but manufacturing cost increases and user experience deteriorates

Engineering Contradiction:
Improveignition propensityVSAvoidmanufacturing cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The invention changes the physical state parameter of the coating material by using phase transition materials that shift from solid to liquid at burning temperatures, fundamentally altering how the coating functions compared to traditional starch-based coatings

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The coating utilizes phase transition properties where the material transitions from solid at room temperature to liquid at burning temperatures, creating a dynamic response that reduces ignition propensity without the drawbacks of starch-based coatings

Inventive Principle:
Principle #36Phase transitions

2Object-affected harmful factors

If starch-based coatings are applied to reduce ignition propensity, then ignition propensity is reduced, but user experience deteriorates

Engineering Contradiction:
Improveignition propensityVSAvoiduser experience
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The phase transition material remains solid during normal handling and only transitions to liquid at burning temperatures, ensuring normal user experience while providing fire safety when needed

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The coating transitions from a static solid structure to a dynamic liquid state in response to temperature changes, allowing it to adapt its properties based on operational conditions

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If a uniform non-continuous layer of phase transition materials is applied, then reproduction consistency improves, but application complexity increases

Engineering Contradiction:
Improvereproduction consistencyVSAvoidapplication complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The coating is applied as a uniform non-continuous layer with specific areal density (0.1-10 mg/in²), creating localized zones of protection that maintain consistency across the wrapper surface

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

By controlling the areal density parameter of the phase transition material application, the invention achieves consistent reproduction of ignition propensity reduction across different manufacturing batches

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 solution effectively reduces ignition propensity while maintaining free burning capability and consumer acceptability, with improved reproducibility and reduced production costs, as the PTM layer is dynamic and moves with the burning cone, ensuring consistent self-extinguishment.

Implementation Method 1

phase transition materials (PTMs) like paraffin, carnauba, and beeswax in a uniform, non-continuous layer on cigarette paper, which transitions from solid to liquid at burning temperatures

Methodology Applied
Scientific EffectPhase transition: Phase Change

Implementation Method 2

forming a dynamic, low-permeability band to reduce oxygen supply and prevent ignition

Methodology Applied
Scientific EffectPermeation: Permeation

Data Source

PatentEP3549457B1Smoking article with reduced ignition propensity
Publication Date: 2023.08.16 R J REYNOLDS TOBACCO COMPANY
  • EP3549457B1 patent drawingFigure 1~2
  • EP3549457B1 patent drawingFigure 3
  • EP3549457B1 patent drawingFigure 4

AI summary

A smoking article having a phase transition substance to impart reduced ignition propensity to a smoking article comprising a tobacco column and a wrapper surrounding the tobacco column and having a porous structure with a base permeability. The smoking article comprises a pattern of phase transition material on a surface of the wrapper such that, when the phase transition material is subjected to the heat of a burning firecone of the tobacco column, the phase transition material at least partially fills the wrapper porous structure in the vicinity of the burning firecone to form an area on the wrapper having a reduced permeability that is lower than the wrapper base permeability, imparting reduced ignition propensity when placed on a substrate.