# US 9,038,644 B2 · Method of applying phase transition materials to semi-porous, flexible substrates used to control gas permeability > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,038,644 B2 - Document ID: US9038644B2 - Status: Granted - Kind: B2 - Application number: 13/412,357 - Filed: 2012-03-05 - Published: 2012-12-06 - Granted: 2015-05-26 - Earliest claimed: 2011-03-04 - Assignees: Lorillard Tobacco Company - Applicants: Steven E. Brown; Alexander J. Dyakonov; Luis A. Sanchez - Inventors: Steven E. Brown; Alexander J. Dyakonov; Luis A. Sanchez - Web page: https://patentgrep.com/patent/US9038644B2 ## CPC - A24D 1/025: {the covers having material applied to defined areas, e.g. bands for reducing the ignition propensity} - A24D: CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES OF CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES ## Abstract Method of applying 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 method comprising forming a pattern of phase transition material on the wrapper such that, when subjected to the heat of the tobacco column burning firecone, 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 reduced permeability lower than that of the wrapper base permeability. The reduced permeability of the wrapper in the vicinity of the burning firecone imparts reduced ignition propensity such that there is insufficient air flow to sustain combustion of the firecone or insufficient air flow to sustain an intensity of the burning firecone necessary to ignite the substrate. ## Claims ### Claim 1 A method of applying a phase transition material to impart reduced ignition propensity to a smoking article, the smoking article comprising a tobacco column and a wrapper surrounding the tobacco column, wherein the wrapper comprises a porous structure with a base permeability, the method comprising forming a pattern of the phase transition material on a surface of the wrapper such that, i) in the absence of heat of a burning firecone, the base permeability of the wrapper is not reduced by more than 20% as a result of the phase transition material, and ii) when the phase transition material is subjected to heat of the burning firecone of the tobacco column, the phase transition material at least partially fills the wrapper porous structure in proximity to the burning firecone to form a non-fixed band on the wrapper having a reduced permeability that is lower than the base permeability; and surrounding the tobacco column with the wrapper; wherein the reduced permeability is selected to permit sufficient air flow through the wrapper to sustain free burn; and further wherein the reduced permeability is also selected to impart reduced ignition propensity when the smoking article is placed on a substrate, such that there is insufficient air flow through the wrapper to sustain combustion of the burning firecone or to sustain an intensity of the burning firecone necessary to ignite the substrate; and further wherein the phase transition material is selected from the group consisting of paraffin, tobacco wax, Solanesol, carnauba, Beeswax, microcrystalline wax or combinations thereof. ### Claim 2 (depends on 1) The method according to claim 1, wherein forming a pattern of the phase transition material on the surface of the wrapper comprises forming a repeatable pattern to essentially the entire surface of the wrapper. ### Claim 3 (depends on 1) The method according to claim 1, wherein forming a pattern of the phase transition material on the surface of the wrapper comprises depositing the phase transition material as a cluster of particles on the surface of the wrapper. ### Claim 4 (depends on 1) The method according to claim 1, wherein forming a pattern of the phase transition material on the surface of the wrapper comprises depositing the phase transition material as a plurality of clusters of particles on the surface of the wrapper. ### Claim 5 (depends on 1) The method according to claim 1, wherein forming a pattern of the phase transition material on the surface of the wrapper comprises forming a pattern on discrete regions of the surface of the wrapper. ### Claim 6 (depends on 1) The method according to claim 1, wherein forming a pattern of the phase transition material on the surface of the wrapper comprises forming a pattern having a gradient of concentration of the phase transition material on the surface of the wrapper. ### Claim 7 (depends on 6) The method according to claim 6, wherein the gradient pattern of the phase transition material, when subjected to the heat of the burning firecone of the tobacco column, forms an area on the wrapper having a variable reduced permeability that is lower than the base permeability. ### Claim 8 (depends on 1) The method according to claim 1, wherein forming a pattern of the phase transition material on the surface of the wrapper comprises depositing a three-dimensional layer of the phase transition material on the surface of the wrapper. ### Claim 9 (depends on 1) The method according to claim 1, wherein forming a pattern of the phase transition material on the wrapper comprises depositing the phase transition material on the surface of the wrapper and applying sufficient pressure to the phase transition material to induce penetration into the surface of the wrapper. ### Claim 10 A method of applying a phase transition material to impart reduced ignition propensity to a smoking article, the smoking article comprising a tobacco column and a wrapper surrounding the tobacco column, wherein the wrapper comprises a porous structure with a base permeability, the method comprising forming a pattern of the phase transition material on a surface of the wrapper such that, i) in the absence of heat of a burning firecone, the base permeability of the wrapper is not reduced by more than 20% as a result of the phase transition material, and ii) when the phase transition material is subjected to heat of the burning firecone of the tobacco column, the phase transition material at least partially fills the wrapper porous structure in proximity to the burning firecone to form a non-fixed band on the wrapper having a reduced permeability that is lower than the base permeability; and surrounding the tobacco column with the wrapper; wherein the reduced permeability is selected to permit sufficient air flow through the wrapper to sustain free burn; and further wherein the reduced permeability is also selected to impart reduced ignition propensity when the smoking article is placed on a substrate, such that there is insufficient air flow through the wrapper to sustain combustion of the burning firecone or to sustain an intensity of the burning firecone necessary to ignite the substrate; and further wherein forming a pattern of the phase transition material on the surface of the wrapper comprises forming a fractal pattern. ### Claim 11 (depends on 10) The method of claim 10, wherein the fractal pattern has varying fractal dimensions. ### Claim 12 (depends on 10) The method of claim 10, wherein forming a pattern of the phase transition material on the surface of the wrapper further comprises forming a repeatable pattern to essentially the entire surface of the wrapper. ### Claim 13 (depends on 10) The method of claim 10, wherein forming a pattern of the phase transition material on the surface of the wrapper further comprises depositing the phase transition material as a cluster of particles on the surface of the wrapper. ### Claim 14 (depends on 10) The method of claim 10, wherein forming a pattern of the phase transition material on the surface of the wrapper further comprises depositing the phase transition material as a plurality of clusters of particles on the surface of the wrapper. ### Claim 15 (depends on 10) The method of claim 10, wherein forming a pattern of the phase transition material on the surface of the wrapper further comprises forming a pattern on discrete regions of the surface of the wrapper. ### Claim 16 (depends on 10) The method of claim 10, wherein forming a pattern of the phase transition material on the surface of the wrapper further comprises forming a pattern having a gradient of concentration of the phase transition material on the surface of the wrapper. ### Claim 17 (depends on 16) The method of claim 16, wherein the gradient pattern of the phase transition material, when subjected to the heat of the burning firecone of the tobacco column, forms an area on the wrapper having a variable reduced permeability that is lower than the base permeability. ### Claim 18 (depends on 10) The method of claim 10, wherein forming a pattern of the phase transition material on the surface of the wrapper further comprises depositing a three-dimensional layer of the phase transition material on the surface of the wrapper. ### Claim 19 (depends on 10) The method of claim 10, wherein forming a pattern of the phase transition material on the wrapper further comprises depositing the phase transition material on the surface of the wrapper and applying sufficient pressure to the phase transition material to induce penetration into the surface of the wrapper. ### Claim 20 (depends on 10) The method of claim 10, wherein the phase transition material is selected from the group consisting of polyethylene, polypropylene, ethylene-stearamide, or combinations thereof.