Carbon Aerosol-Forming Substrate for Uniform Heating

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Solution Overview

Problem

Existing aerosol-forming substrates have low thermal conductivity, leading to uneven temperature distribution and reduced efficiency in releasing volatile compounds, and often require separate susceptor elements for induction heating, increasing costs.

Innovation Solution

Incorporating thermally conductive particles such as graphite, expanded graphite, graphene, carbon nanotubes, charcoal, or diamond into the aerosol-forming substrate, along with fibers and a binder, to enhance thermal conductivity and tensile strength, allowing for more uniform heating and potentially eliminating the need for a susceptor element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If thermally conductive particles are incorporated into the aerosol-forming substrate, then thermal conductivity is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvethermal conductivityVSAvoidmanufacturing complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent applies composite materials by incorporating thermally conductive particles (such as graphite, expanded graphite, graphene, carbon nanotubes, charcoal, or diamond) into the aerosol-forming substrate matrix. This creates a composite structure that combines the base substrate material with high thermal conductivity particles, achieving enhanced thermal conductivity (k ≥ 0.1 W/mK) while maintaining the substrate's functional properties for aerosol generation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the thermal conductivity parameter of the substrate by controlling the type, amount, and distribution of thermally conductive particles. By adjusting particle concentration and selecting different particle types with varying thermal conductivities, the substrate's overall thermal conductivity can be tuned to meet specific performance requirements while balancing manufacturing considerations.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If thermally conductive particles are incorporated into the aerosol-forming substrate, then temperature distribution uniformity is improved, but production cost increases

Engineering Contradiction:
Improvetemperature distribution uniformityVSAvoidproduction cost
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent applies local quality by strategically distributing thermally conductive particles throughout the substrate to create regions of enhanced thermal conductivity where needed. This ensures uniform temperature distribution across the substrate during heating, particularly near the heating element, while allowing other regions to maintain their base material properties, optimizing both performance and cost-effectiveness.

Inventive Principle:
Principle #3Local quality

3Productivity

If the substrate has higher thermal conductivity, then usage efficiency is improved, but material cost increases

Engineering Contradiction:
Improveusage efficiencyVSAvoidmaterial cost
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent optimizes the concentration and type of thermally conductive particles to achieve the minimum required thermal conductivity (k ≥ 0.1 W/mK) necessary for adequate usage efficiency. By carefully controlling particle content and selecting cost-effective particle types (such as graphite or charcoal versus more expensive graphene or diamond), the patent balances usage efficiency improvements with material cost considerations.

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 improved thermal conductivity results in a more even temperature distribution, higher efficiency in releasing volatile compounds, and reduces the power requirements and time needed for aerosol formation, while also enhancing the substrate's tensile strength and production feasibility.

Implementation Method 1

The improved substrate has an increased thermal conductivity... the thermally conductive particles may increase the thermal conductivity of the aerosol-forming substrate... provide a more even temperature distribution throughout the substrate during use

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a blade is inserted into the aerosol-forming substrate and heated in order to heat the aerosol-forming substrate

Methodology Applied
Scientific EffectConductive heating: Conduction (thermal)

Implementation Method 3

heat the aerosol-forming substrate and cause the aerosol-forming substrate to release volatile compounds. These compounds then cool to form an aerosol

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4706410A1Improved aerosol-forming substrate
Publication Date: 2026.03.11 PHILIP MORRIS PRODUCTS SA
  • EP4706410A1 patent drawingFigure 1~2
  • EP4706410A1 patent drawingFigure 3~4
  • EP4706410A1 patent drawingFigure 5

AI summary

There is provided an aerosol-forming substrate comprising, on a dry weight basis: between 10 and 90 wt % carbon particles; between 7 and 60 wt % of an aerosol former; between 2 and 20 wt % of fibres; and between 2 and 10 wt % of a binder. Each of the carbon particles consists of one or more of graphite, expanded graphite, graphene, carbon nanotubes, charcoal, and diamond. There is also provided an aerosol-generating article comprising the aerosol-forming substrate and a method of forming the aerosol-forming substrate.