Smoking articles with reduced ignition proclivity characteristics
View Patent ↗A process for reducing the permeability of a paper wrapper used in the construction of a smoking article is disclosed. The paper wrapper is treated with a film-forming composition that forms treated discrete areas on the wrapper. The treated discrete areas have a permeability within a predetermined range sufficient to reduce the ignition proclivity properties of a smoking article made with the wrapper. In accordance with the present invention, the film-forming composition contains a film-forming material. The film-forming material has a relatively low viscosity. In this manner, the film-forming composition can have a relatively high solids content and still be applied to the wrapper using conventional techniques, such as by using a gravure printer.
1. A process for producing a paper wrapper having reduced ignition proclivity characteristics when incorporated into a smoking article comprising:
applying a film-forming composition to a paper wrapper at particular locations, the film-forming composition including a film-forming material comprising at least one of alginate, guar gum, pectin, polyvinyl alcohol, a cellulose derivative, starch, a starch derivative, or mixtures thereof, the film-forming material having a molecular weight such that the film-forming material has a viscosity of less than about 500 cP when present in a 3% by weight aqueous solution at 25° C., the film-forming composition forming treated discrete areas on the paper wrapper, the treated discrete areas being separated by untreated areas, the treated discrete areas having a BMI of less than 5 cm −1 , the treated areas having a permeability of less than about 40 Coresta, the untreated areas of the paper wrapper having a permeability of about 55 Coresta to about 110 Coresta.
2. The process of claim 1 , wherein the film-forming material is present in the composition such that the film-forming composition has a solids content of at least 6% by weight.
3. The process of claim 1 , wherein the film-forming material has a viscosity of less than about 250 cP when present in a 3% by weight solution at 25° C.
4. The process of claim 1 , wherein the alginate comprises a sodium alginate.
5. The process of claim 1 , wherein the treated areas have a BMI of from about 1 cm −1 to about 5 cm −1 .
6. The process of claim 1 , wherein the film-forming composition is printed onto the paper wrapper.
7. The process of claim 6 , wherein the film-forming composition is printed onto the paper wrapper in a multi-pass operation.
8. The process of claim 1 , wherein the treated areas comprise a plurality of discrete circumferential bands disposed longitudinally along the paper wrapper, the bands having a width of greater than 4 mm, the bands being spaced from each other from a distance of from about 10 mm to about 40 mm.
9. The process of claim 1 , wherein the film-forming composition is applied to the paper wrapper using gravure printing.
10. The process of claim 1 , wherein the film-forming composition is applied to the paper wrapper in the treated discrete areas in an amount up to about 30% by weight based upon a basis weight of the paper wrapper.
11. A process as defined in claim 1 , further comprising the step of drying the paper wrapper after the film-forming composition has been applied.
12. A process as defined in claim 1 , further comprising the step of incorporating the paper wrapper into a smoking article, the smoking article comprising a column of a smokable tobacco, the column of the smokable tobacco being surrounded by the paper wrapper.
13. A process as defined in claim 1 , wherein the film-forming composition comprises an aqueous composition.