Cigarette Wrapper Banded Pattern for Ignition Propensity Control
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Solution Overview
Problem
Smoking articles with low Ignition Propensity (IP) values often self-extinguish when not in use, which is undesirable for adult consumers, and achieving a balance between low IP and Self-Extinguishment (SE) values is challenging while meeting governmental regulations.
Innovation Solution
A cigarette wrapper with circumferential banded regions of add-on material applied in a sawtooth pattern, using an aqueous starch solution containing an anti-wrinkling agent like propylene glycol, which is printed in a single pass to maintain low diffusivity and prevent self-extinguishment during free burn conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If add-on material is applied to reduce Ignition Propensity, then the smoking article is less likely to cause ignition, but it tends to self-extinguish during free burn
Solution Approach 1:
The wrapper features banded regions with add-on material applied only in specific circumferential bands rather than uniformly across the entire wrapper. This localized application creates regions of different permeability - the banded regions have lower permeability to reduce ignition propensity, while the non-banded regions maintain higher permeability to support continuous combustion during free burn, thus resolving the contradiction between low IP and low SE values
Solution Approach 2:
The wrapper is segmented into distinct banded regions and non-banded regions with different material properties. The add-on material is applied in discrete bands with specific spacing and width parameters, creating a segmented structure that allows different portions of the wrapper to perform different functions - some portions suppress ignition while others maintain burn continuity
2Productivity
If add-on material is applied in a single pass printing operation, then productivity is improved, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent specifies precise parameters for the single-pass printing operation including add-on material application rate, band width, band spacing, and drying conditions. By optimizing these parameters, the process achieves both high productivity through single-pass operation and manufacturing precision through consistent pattern formation. The add-on rate is controlled to provide sufficient material for IP reduction while maintaining pattern uniformity across the wrapper surface
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 achieves remarkably low IP and SE values that satisfy governmental regulations, ensuring the smoking article does not self-extinguish when not in use while maintaining a reduced likelihood of ignition, thus providing a balanced performance.
Implementation Method 1
The bands of either embodiment are longitudinally spaced from one another by a distance of preferably about 20 to about 22 mm and the add-on material is applied at a rate sufficient to provide a diffusivity value in the range of about 0.0 to about 0.20 centimeters per second, more preferably, less than about 0.10 cm/sec.
Implementation Method 2
The printing solution contains an anti-wrinkling agent like propylene glycol
Data Source
AI summary
A wrapper for a smoking article has a base web and a plurality of crenellated bands, each having a diffusivity value in the range of 0 to about 0.2 cm/sec. The add-on material can be applied by gravure printing in a single pass in a chevron pattern such that an apex of the element is co-linear with substantially symmetrically spaced points on a trailing, outer edge of an adjacent chevron element. Testing elements may be simultaneously printed with the add-on material to monitor diffusivity and/or presence of add-on material.