Patent Publication Number: US-2020275690-A1

Title: Gravure printed banded wrapper paper

Description:
BACKGROUND 
     As part of efforts to reduce the incidence of accidental fires resulting from untended smoking articles, various jurisdictions have imposed, are imposing, and may impose in the future limitations on the burning characteristics of smoking articles. One measure of the tendency of a smoking article to cause ignition of an underlying substrate is the Ignition Propensity value. To meet common governmental requirements, the Ignition Propensity value, or IP value, for a smoking article should preferably be no greater than about 25%, when tested in accordance with ASTM E2187. More preferably, the IP value should be no greater than about 20%, and even more preferably no greater than about 10%. Accordingly, efforts to meet such limits are undertaken by various manufacturers of smoking articles. 
     SUMMARY 
     According to an example disclosed herein, a smoking article includes a tobacco rod comprising a column of filler and a wrapper surrounding the column of filler. The tobacco rod has a circumferential direction, a longitudinal direction, a lit end, and a mouth end. The wrapper includes a base web having generally parallel first and second side edges extending in the longitudinal direction and two ends extending in the circumferential direction wherein the base web is disposed around the column of filler such that the first and second side edges of the base web overlap and form a seam. The base web includes at least one circumferentially extending banded region of fibrous crystalline cellulosic material thereon. The fibrous crystalline cellulosic material is in a condition of having been gravure printed on the base web as a fibrous crystalline cellulosic slurry that comprises water, crystalline cellulose, and chalk wherein the fibrous crystalline cellulosic slurry has a solids content of about 10% or less by weight of the fibrous crystalline cellulosic slurry. 
     According to an example disclosed herein, a wrapper for smoking articles includes a base web having generally parallel first and second side edges extending in a longitudinal direction, two ends extending in a transverse direction, and a plurality of longitudinally spaced banded regions of fibrous crystalline cellulosic material thereon, the fibrous crystalline cellulosic material having been gravure printed on the base web as a fibrous crystalline cellulosic slurry comprising water, crystalline cellulose, and chalk wherein the fibrous crystalline cellulosic slurry has a solids content of about 10% or less by weight of the fibrous crystalline cellulosic slurry. 
     According to an example disclosed herein, a method of making banded wrapper paper for smoking articles includes advancing a base web to a first printing station and printing a first layer of a fibrous crystalline cellulosic slurry on the base web. The fibrous crystalline cellulosic slurry includes water, crystalline cellulose, and chalk and has a solids content of about 10% or less by weight of the fibrous crystalline cellulosic slurry. The printing includes applying the fibrous crystalline cellulosic slurry to a patterned gravure roller, and contacting the advancing base web with the patterned gravure roller to apply bands of the fibrous crystalline cellulosic slurry on the base web. Banded regions of fibrous crystalline cellulosic material are formed on the base web by drying the bands of the fibrous crystalline cellulosic slurry. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an example embodiment of a smoking article having banded wrapper paper as described herein. 
         FIG. 2  is a schematic view of an example embodiment of banded wrapper paper as described herein. 
         FIG. 3  is a schematic view of an example gravure printing process suitable for producing embodiments of banded wrapper paper as described herein. 
         FIG. 4  is an illustration of an example embodiment of a gravure cylinder as described herein. 
         FIGS. 5A, 5B, and 5C  are illustrations of an example embodiment of a gravure cylinder etching process. 
         FIG. 6  is a schematic view of an example embodiment of banded wrapper paper as described herein. 
         FIG. 7  is an illustration of an example embodiment of a gravure cylinder as described herein. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a smoking article  120 , such as a cigarette, can comprise a tobacco rod  122  and a filter  132  attached to one end of the tobacco rod  122  with tipping paper  129 . The tobacco rod  122  comprises a column of shredded tobacco (“cut filler”) and a piece of banded wrapper paper  123  disposed about the column of shredded tobacco. 
     The tobacco rod  122  has a lightable or lit end  124  and a tipped end  130 , which, in the case of non-filtered cigarettes, is referenced as the mouth end  130  of the smoking article  120 . Cut filler tobacco is an industry-standard designation. In an example embodiment, the tobacco rod  122  has a generally circular cross section. In other example embodiments, the tobacco rod  122  can have an oval cross section or other non-circular shape cross section. The wrapper  123  is sealed along a longitudinal seam to form the tobacco rod  122 . 
     The smoking article  120  has a nominal length measured from the edge  131  of the tipping paper to the lit end  124  of the tobacco rod  122  along a longitudinal axis of smoking article  120 . By way of example, that nominal length may lie in the range of about 60 to about 100 mm. 
     As shown in  FIG. 2 , the banded wrapper paper  123  can include a base web  140  that may be made from flax, wood pulp, cellulose fiber, or the like. In an example embodiment, the base web  140  has a plurality of bands of fibrous crystalline cellulosic material  126  on one or both sides thereof. In an example embodiment, the bands of fibrous crystalline cellulosic material  126  are applied to a wire side of the base web  140  such that they are on the inside of the banded wrapper paper  123  when a piece of the wrapper  123  surrounds a column of shredded tobacco to form a tobacco rod  122 . 
     In the manufacture of base web  140  suited for the construction of the various embodiments of banded wrapper paper disclosed herein, such manufacture usually will include the production of a roll of base web  140  of several feet across (usually about 3 feet to about 5 feet across or in transverse dimension), which is then slit into ribbons that are wound on bobbins. Printing operations are conducted on the rolls, but could be conducted after slitting. The bobbins themselves will have a transverse dimension equivalent to the width needed to make tobacco rods  122  or an integral number of such widths (e.g., 1, 2, or 4 of such widths). The bobbins are adapted for use with typical cigarette making machines. In an example embodiment, the banded wrapper paper has a dimension in cross-direction that takes into account the nominal circumference of the tobacco rod  122  and an overlapping seam. As a result, when the banded wrapper paper  123  is slit, the smoking article  120  formed therefrom always has a longitudinal seam with an exact overlap. 
     For purposes of this disclosure, “longitudinal” refers to the direction along the length of a tobacco rod  122  (e.g., along the axis  134  in  FIG. 1 ), or along the length of a base web  140  (e.g., arrow  142  in  FIGS. 2 and 6 ) used in the preparation of banded wrapper paper  123  that, in turn, may be used to fabricate a tobacco rod  122 . 
     For purposes of this disclosure, “transverse” refers to the direction circumferentially around a tobacco rod  122  (see  FIG. 1 ) or the direction perpendicular to the length of the base web  140  (e.g., arrow  144  in  FIGS. 2 and 6 ) used in the preparation of banded wrapper paper  123  that, in turn, may be used to fabricate a tobacco rod  122 . 
     For purposes of this disclosure, a “band” or “banded region”  126  is an area (see  FIG. 2 ) on an underlying base web  140  to which a fibrous crystalline cellulosic slurry has been printed to form a region of fibrous crystalline cellulosic material. As used herein, the phrase “leading edge” refers to the edge  146  (see  FIG. 1 ) of a banded region  126  that is closest to an approaching coal during smoldering of a smoking article  120  whose wrapper  123  contains the banded region  126 , while the phrase “trailing edge” refers to the edge  148  of a banded region  126  that is farthest from an approaching coal during smoldering of a smoking article  120  whose wrapper  123  contains the banded region  126 . As used herein, “band spacing” refers to the distance between the trailing edge  148  of one banded region  126  and the leading edge  146  of an adjacent banded region  126  on the base web  140  from which banded wrapper paper  123  is fashioned. As used herein, “phase” refers to the distance from the leading edge  146  of one banded region  126  to the leading edge  146  of an adjacent banded region  126 . 
     In an example embodiment, the banded regions of fibrous crystalline cellulosic material  126  extend transversely across the base web  140  and are separated by regions free of added fibrous crystalline cellulosic material in the longitudinal direction  142  of the base web  140 . The banded regions of fibrous crystalline cellulosic material  126  are applied to the base web  140  of the banded wrapper paper  123  to obtain satisfactory or improved Ignition Propensity (“IP”) characteristics for a smoking article including a piece of the banded wrapper paper  123  and optionally to also obtain improved Self-Extinguishment (“SE”) characteristics for the smoking article. 
     In an example embodiment, the banded regions of fibrous crystalline cellulosic material  126  are arranged on the base web  140  such that at least one banded region of fibrous crystalline cellulosic material  126  is positioned between the lit end  124  and the tipped end  130  of the tobacco rod  122  in each finished smoking article  120  that includes the banded wrapper paper  123 . In an example embodiment, at least two banded regions of fibrous crystalline cellulosic material  126  are positioned between the lit end  124  and the tipped end  130  of the tobacco rod  122  in each finished smoking article  120  that includes the banded wrapper paper  123 . In an example embodiment, the banded regions of fibrous crystalline cellulosic material  126  extend circumferentially around the tobacco rod at one or more longitudinally spaced locations along the axis  134  thereof. 
     It is noted for sake of convention that, in describing dimensions of various embodiments herein, that band or banded region “width” extends in a longitudinal direction along axis  142  of the base web  140  (see  FIG. 2 ) or axis  134  of the tobacco rod  122 , whereas a dimension in the circumferential direction will be expressed as “circumferential” or “transverse” or “in cross-direction.” 
     In an example embodiment, where the banded regions of fibrous crystalline cellulosic material  126  extend transversely across the base web  140  (or circumferentially around a tobacco rod  122 ), the “width” of the banded regions of fibrous crystalline cellulosic material  126  is measured in the longitudinal direction  142  from a leading edge  146  to a trailing edge  148  thereof. In an example embodiment, the widths of the banded regions of fibrous crystalline cellulosic material  126  are each about 5 to about 9 mm (from the leading edge  146  to the trailing edge  148 ). In an example embodiment, the widths of the banded regions of fibrous crystalline cellulosic material  126  are each about 5.5 to about 7.5 mm. In an example embodiment, the widths of the banded regions of fibrous crystalline cellulosic material  126  are each about 6 to about 7 mm. In an example embodiment, adjacent banded regions of fibrous crystalline cellulosic material  126  are longitudinally spaced by regions of the base web  140  free of added fibrous crystalline cellulosic material by a distance of about 20 mm to about 30 mm. In an example embodiment, the phase (i.e., the spacing from the leading edge  146  of one banded region  126  to the leading edge  146  of an adjacent banded region  126 ) is about 25 mm or 27 mm. While the banded regions of fibrous crystalline cellulosic material  126  are depicted in this disclosure as solid bands, other configurations of the banded regions  126  on the base web  140  are within the spirit and scope of this disclosure, including, but not limited to, configurations in which the banded regions  126  have one or more areas free of added fibrous crystalline cellulosic material between the leading and trailing edges  146 ,  148  thereof 
     The base web  140  of the banded wrapper paper  123  is permeable to air. Permeability of the base web  140  is typically identified in CORESTA units. A CORESTA unit measures paper permeability in terms of volumetric flow rate (i.e., cm 3 /sec) per unit area (i.e., cm 2 ) per unit pressure drop (i.e., cm of water). In example embodiments, the base web  140  of the banded wrapper paper  123  has a permeability of at least about 20 CORESTA units and a basis weight of about 22 to 30 gram(s) per square meter in regions outside of the banded regions of fibrous crystalline cellulosic material  126 . In this specification, the unit of measurement for basis weight, gram(s) per square meter, is abbreviated as “gsm”. In example embodiments, the base web  140  of the banded wrapper paper  123  has a permeability of at least about 20 CORESTA units and a basis weight of about 25 to 27 gsm in regions outside of the banded regions of fibrous crystalline cellulosic material  126 . In an example embodiment, the base web  140  of the wrapper  123  has a permeability greater than about 30 CORESTA in regions outside of the banded regions of fibrous crystalline cellulosic material  126 . In an example embodiment, the base web  140  of the wrapper  123  has a permeability of about 33 CORESTA with a basis weight of about 25 gsm in regions outside of the banded regions of fibrous crystalline cellulosic material  126 . In an example embodiment, the base web  140  of the wrapper  123  has a permeability of about 46 CORESTA with a basis weight of about 25 gsm in regions outside of the banded regions of fibrous crystalline cellulosic material  126 . In an example embodiment, the base web  140  of the wrapper  123  has a permeability of about 60 CORESTA in regions outside of the banded regions of fibrous crystalline cellulosic material  126 . In an example embodiment, the base web  140  of the wrapper  123  has a permeability of about 60 CORESTA with a basis weight of about 25 gsm in regions outside of the banded regions of fibrous crystalline cellulosic material  126 . In an example embodiment, the base web  140  of the wrapper  123  has a permeability of about 60 CORESTA with a basis weight of about 26 gsm in regions outside of the banded regions of fibrous crystalline cellulosic material  126 . In example embodiments, the base web  140  has a permeability greater than about 60 CORESTA with a basis weight of about 25 gsm or more, a permeability greater than about 80 CORESTA with a basis weight of about 25 gsm or more, or a permeability greater than about 100 CORESTA with a basis weight of about 25 gsm or more in regions outside of the banded regions of fibrous crystalline cellulosic material  126 . 
     In example embodiments, application of the fibrous crystalline cellulosic slurry to a base web  140  and drying thereof, forms a banded region of fibrous crystalline cellulosic material  126  on the base web  140  that is effective to locally reduce the permeability of the base web  140  within the banded region  126 . In example embodiments, bands of fibrous crystalline cellulosic slurry are printed on the base web  140  with a gravure roller  610  to reduce the permeability of the base web  140  within the banded regions of fibrous crystalline cellulosic material  126  to about 0 to about 12 CORESTA. In an example embodiment, the permeability of the base web  140  within the banded regions of fibrous crystalline cellulosic material  126  is 7 CORESTA or less. 
     In example embodiments, application of the fibrous crystalline cellulosic slurry to the base web  140  and drying thereof, forms a banded region of fibrous crystalline cellulosic material  126  on the base web  140  that is effective to locally reduce diffusivity values of the base web  140  from a diffusivity level of about 2 cm/sec or greater (for the base web  140  in regions free of added fibrous crystalline cellulosic material) to a value in the range of 0.0 to about 0.2 cm/sec as measured by a Sodium CO 2  Diffusivity Tester (purchased from Sodium SAS of France). To measure the diffusivity of a piece of banded wrapper paper  123  using a Diffusivity Tester, the banded wrapper paper  123  is positioned within a clamping head so that the banded wrapper paper  123  separates two vertically arranged chambers. The upper chamber contains a carrier gas, such as nitrogen, while the lower chamber contains a marker gas, such as carbon dioxide. There is no pressure difference between the two chambers such that there is no permeability effect, which occurs when a pressure difference is maintained between two surfaces of the banded wrapper paper  123 . As such, any migration of gases between the two chambers is due to differences in concentrations of the gases. After a predetermined period of time (e.g., for about 25 seconds or less), the concentration of carbon dioxide within the nitrogen stream of the upper chamber is measured in an analyzer. A computer then converts the detected level of concentration into a measure of diffusivity. In an example embodiment, the diffusivity of the base web  140  within the banded regions of fibrous crystalline cellulosic material  126  is less than about 0.15 cm/sec. In an example embodiment, the diffusivity of the base web  140  within the banded regions of fibrous crystalline cellulosic material  126  is about 0 to about 0.1 cm/sec (e.g. about 0.01 to about 0.09 cm/sec, about 0.02 to about 0.08 cm/sec, about 0.03 to about 0.07 cm/sec or about 0.04 to about 0.06 cm/sec). 
     As used herein, “layer” refers to a quantity of fibrous crystalline cellulosic slurry printed on the base web  140  by a gravure roller from which banded wrapper paper  123  is fabricated. In an example embodiment, each banded region of fibrous crystalline cellulosic material  126  may be formed by gravure printing a “layer” of a fibrous crystalline cellulosic slurry on the base web  140  to reduce the permeability of the base web  140  in the corresponding banded region. In an example embodiment, the fibrous crystalline cellulosic slurry is aqueous. 
     To form the banded regions of fibrous crystalline cellulosic material  126 , a single pass or multi-pass gravure printing process can be utilized. Alternatively, multiple pass gravure printing can be utilized.  FIG. 3  is a schematic view of a single stage printing apparatus  602 . With reference to the above-description for printing, a supply reel  601  supplies a blank base web  140  to a gravure printing station  602  where a banded region of fibrous crystalline cellulosic slurry is printed on the blank base web  140  by the gravure roller  610  and dried in a drier  634 . In an example embodiment, the drier  634  can include at least one steam can. In an example embodiment, the drier  634  can include two steam cans wherein the base web  140  is advanced and pressed between the steam cans to reduce wrinkling of the base web  140 . The dried, patterned base web  140  then advances to a collection reel  608 . If desired, a wide base web  140  may be slit or divided by a slitter  635  into a plurality of narrower strips of base web that may be wound to form individual bobbins after the printing operation, where the bobbins have a width corresponding to that required for a smoking article  120 . The optional slitter  635  may be used on the base web  140  as that base web  140  leaves the printing station, or the slitter and slitting operation may be conducted at a different location. 
     Example embodiments of gravure printing the fibrous crystalline cellulosic slurry as disclosed herein enable high-speed printing on the base web  140 . For purposes of this disclosure, “high-speed” printing refers to printing processes where the base web  140  advances through the printing process at a linear speed greater than about 300 feet/min. In an example embodiment, the size of the crystalline fibers in the fibrous crystalline cellulosic slurry, and the deposition rate and viscosity of the fibrous crystalline cellulosic slurry are selected such that base web printing speeds of greater than 500 feet/minute can be achieved. 
     As shown in  FIG. 4 , the gravure cylinder (roller)  610  includes a plurality of cells  700  arranged in a pattern corresponding to a band that is to be printed on the base web  140  by the gravure roller  610 . In an example embodiment, the gravure cylinder  610  includes two or more circumferentially spaced regions  701  of cells  700  wherein each region  701  of cells  700  is arranged in a pattern corresponding to a band that is to be printed on the base web  140  by the gravure roller  610 . In this embodiment, adjacent regions  701  of cells  700  are circumferentially spaced by cell free surfaces  703  of the gravure roller  610  which extend a distance corresponding to the spacing between adjacent banded regions to be printed on the base web  140 . In an embodiment, the pattern of cells  700  corresponding to banded regions are arranged in a chevron pattern wherein angle “A” at the tip or apex of the chevron is preferably greater than about 170 degrees. Such arrangement helps distribute stress due to shrinkage in the base web  140  upon application of the fibrous crystalline cellulosic slurry and drying, which in turn, helps alleviate the tendency of the paper to pucker or wrinkle in the course of gravure printing operations. 
     In an example embodiment, as shown in  FIGS. 5A, 5B, and 5C , the cells of the gravure roller  610  can be formed by etching the gravure roller  610 . Suitable etching processes and gravure cylinders can be obtained from Heliograph Holding GmbH. In an example embodiment, photoresist  801  is applied to a metallic surface  800 , and lasers  802  are used to activate the photoresist, which serves to mask areas where walls are desired. In an example embodiment, as shown in  FIG. 4 , the gravure roller  610  (shown in  FIG. 4 ) has a plurality of cells  700  which have a generally hexagonal shape. In an example embodiment, the cells  700  of the gravure roller  610  can have walls  702  ranging from about 12 to about 80 microns in width between adjacent cells  700  depending on the desired final volume of each cell  700 . In an example embodiment, the cells  700  of the gravure roller  610  can have walls  702  ranging from about 12 to about 20 microns in width between adjacent cells  700 . In an example embodiment, the gravure cylinder  610  can be formed such that certain cells within a region of cells are thinner than walls of other cells of the gravure roller  610 . In an example embodiment, the cells  700  of the gravure roller  610  can have a generally circular shape. In an example embodiment, the depth of the cells  700  is uniform. However, in other embodiments, the depth of the cells  700  can vary. 
     In use, the cells  700  are filled with the fibrous crystalline cellulosic slurry such that they may print the fibrous crystalline cellulosic slurry on the base web  140 . In an example embodiment, the cells  700  are sized to print dots of the fibrous crystalline cellulosic slurry which spread to form a continuous band of fibrous crystalline cellulosic material  126  on the base web  140  when the fibrous crystalline cellulosic slurry is dried. In an example embodiment, the cells  700  are sized to print dots of the fibrous crystalline cellulosic slurry to form a substantially continuous band of fibrous crystalline cellulosic material  126  on the base web  140  when the fibrous crystalline cellulosic slurry is dried. In an example embodiment, the cells  700  are sized to print small enough dots of the fibrous crystalline cellulosic slurry to form a non-continuous band of fibrous crystalline cellulosic material  126  on the base web  140  when the fibrous crystalline cellulosic slurry is dried wherein one or more areas within the non-continuous band of fibrous crystalline cellulosic material  126  are free of added fibrous crystalline cellulosic material. Adjustment of diffusivity of the banded regions of fibrous crystalline cellulosic material  126  can be facilitated by changing the size and/or number of cells  700  which apply fibrous crystalline cellulosic slurry. 
     In the printing station  602 , a gravure roller  610  is supplied fibrous crystalline cellulosic slurry, and moves through a doctor blade  630  that extends along the length of the gravure roller  610 . The doctor blade  630  is positioned so that is wipes the surface of the gravure roller  610  such that portions  703  of the gravure roller  610  that define the nominal spacing between adjacent banded regions  126  are essentially wiped clean of the fibrous crystalline cellulosic slurry, while the cells  700  of the gravure roller  610  advance toward a nip  616  of the printing station  602  full of the fibrous crystalline cellulosic slurry. The gravure roller  610  contacts one side of the base web  140  in the nip  616  between the gravure roller  610  and an impression cylinder  612  to print the fibrous crystalline cellulosic slurry in the cells of the gravure roller  610  on the base web  140 . In an example embodiment, the fibrous crystalline cellulosic slurry is delivered from a reservoir  618  to an applicator  624  by a suitable pump  620 . The fibrous crystalline cellulosic slurry is spread on the gravure roller  610  by the applicator  624 . Excess fibrous crystalline cellulosic slurry accumulates in a bath  626  from which excess fibrous crystalline cellulosic slurry returns to the reservoir  618 . In an example embodiment, the fibrous crystalline cellulosic slurry is continuously circulated between the reservoir  618  and the bath  626  to prevent the solids in the fibrous crystalline cellulosic slurry from settling in the bottom of the reservoir  618  or the bottom of the bath  626 . In an example embodiment, the fibrous crystalline cellulosic slurry in the reservoir  618  is continuously agitated or mixed, to prevent solids in the fibrous crystalline cellulosic slurry from settling in the bottom of the reservoir  618 . In an embodiment, the fibrous crystalline cellulosic slurry printed on the base web  140  at room temperature. In an embodiment, the fibrous crystalline cellulosic slurry printed on the base web  140  at a temperature less than about 38° C. 
     In an example embodiment, the fibrous crystalline cellulosic slurry can be prepared by mixing fibrous crystalline cellulosic material and chalk with a sufficient amount of water to make an aqueous slurry having a composition of less than about 10% solids. In an example embodiment, the fibrous crystalline cellulosic material is insoluble in the water such that mixing the fibrous crystalline cellulosic material and chalk with the water suspends the fibrous crystalline cellulosic material and the chalk in the water to form a stable slurry. In an example embodiment, the fibrous crystalline cellulosic material is free of any modified cellulose. In an example embodiment, the fibrous crystalline cellulosic material is free of any binders. In an example embodiment, the fibrous crystalline cellulosic material is free of any binders and modified cellulose. In an example embodiment, the fibrous crystalline cellulosic material is free of any bacterial cellulose. In an example embodiment, the fibrous crystalline cellulosic material is microcrystalline cellulose and is free of any binders and modified cellulose. In an example embodiment, the fibrous crystalline cellulosic material is microcrystalline cellulose and a binder. 
     In an example embodiment, the fibrous crystalline cellulosic material includes microcrystalline cellulose and a binder, and is free of any modified cellulose. In an example embodiment, the fibrous crystalline cellulosic material is free of starch, guar gum, alginate, and/or cellulose derivatives. In an example embodiment, the fibrous crystalline cellulosic material is free of any film forming material. In an example embodiment, the fibrous crystalline cellulosic material includes a binder such as sodium carboxymethyl cellulose or carboxymethyl cellulose. In an example embodiment, the fibrous crystalline cellulosic material includes a binder such as sodium carboxymethyl cellulose or carboxymethyl cellulose. In an example embodiment, the fibrous crystalline cellulosic material includes microcrystalline cellulose and a binder wherein the binder is less than about 9% by weight of the fibrous crystalline cellulosic material. 
     In an example embodiment, the fibrous crystalline cellulosic material includes AVICEL™ microcrystalline cellulose. In an example embodiment, the fibrous crystalline cellulosic material includes microcrystalline cellulose and a binder, and is free of any modified cellulose. In an example embodiment, the fibrous crystalline cellulosic material includes microcrystalline cellulose wherein the fibers of the microcrystalline cellulose are predominately of a size of about 200 microns or less. In an example embodiment, the fibrous crystalline cellulosic material includes microcrystalline cellulose wherein at least 90% of the fibers of the microcrystalline cellulose have a size of about 200 microns or less. In an example embodiment, the fibrous crystalline cellulosic material includes microcrystalline cellulose wherein the fibers of the microcrystalline cellulose are predominately of a size of about 10 microns or more. 
     In an example embodiment, the fibrous crystalline cellulosic material is insoluble in room temperature water wherein the fibrous crystalline cellulosic material is mixed with room temperature water. In an embodiment, the fibrous crystalline cellulosic material is insoluble in water having a temperature less than about 38° C. wherein the fibrous crystalline cellulosic material is mixed with water having a temperature less than about 38° C. In an example embodiment, the fibrous crystalline cellulosic material and chalk is mixed with non-deionized water such as tap water. In an example embodiment, the fibrous crystalline cellulosic slurry is a composition having less than about 9.5% fibrous crystalline cellulosic material and less than about 5.5% chalk. In an example embodiment, the fibrous crystalline cellulosic slurry is a composition having about 9.5% fibrous crystalline cellulosic material and about 5.5% chalk. In an example embodiment, the fibrous crystalline cellulosic slurry includes up to 9.5 weight % cellulosic fibrous crystalline material and up to 5.5 weight % chalk. In an embodiment, a room temperature viscosity of the fibrous crystalline cellulosic slurry is no greater than about 40 centipoises. In an example embodiment, a room temperature viscosity of the fibrous crystalline cellulosic slurry is between about 30 to 40 centipoises. In an embodiment, a room temperature viscosity of the fibrous crystalline cellulosic slurry is less than about 30 to 40 centipoises. 
     In an example embodiment, the fibrous crystalline cellulosic slurry is a composition having less than about 10% solids wherein a ratio fibrous crystalline cellulosic material to chalk in the fibrous crystalline cellulosic slurry is about 95 to 5. In an example embodiment, the fibrous crystalline cellulosic slurry is a composition having less than about 8% solids wherein a ratio fibrous crystalline cellulosic material to chalk in the fibrous crystalline cellulosic slurry is about 95 to 5. In an example embodiment, the fibrous crystalline cellulosic slurry is a composition having less than about 6% solids wherein a ratio fibrous crystalline cellulosic material to chalk in the fibrous crystalline cellulosic slurry is about 95 to 5. In an embodiment, the fibrous crystalline cellulosic slurry is a composition having less than about 5% solids wherein a ratio fibrous crystalline cellulosic material to chalk in the fibrous crystalline cellulosic slurry is about 95 to 5. In an embodiment, the fibrous crystalline cellulosic slurry is a composition having about 2% solids wherein a ratio fibrous crystalline cellulosic material to chalk in the fibrous crystalline cellulosic slurry is about 95 to 5. In an embodiment, the fibrous crystalline cellulosic slurry is a composition having less than about 10% solids wherein a ratio fibrous crystalline cellulosic material to chalk in the fibrous crystalline cellulosic slurry is about 94.5 to 5.5. In an embodiment, the fibrous crystalline cellulosic slurry is a composition having less than about 8% solids wherein a ratio fibrous crystalline cellulosic material to chalk in the fibrous crystalline cellulosic slurry is about 94.5 to 5.5. In an embodiment, the fibrous crystalline cellulosic slurry is a composition having less than about 6% solids wherein a ratio fibrous crystalline cellulosic material to chalk in the fibrous crystalline cellulosic slurry is about 94.5 to 5.5. In an embodiment, the fibrous crystalline cellulosic slurry is a composition having less than about 5% solids wherein a ratio fibrous crystalline cellulosic material to chalk in the fibrous crystalline cellulosic slurry is about 94.5 to 5.5. In an embodiment, the fibrous crystalline cellulosic slurry is a composition having about 2% solids wherein a ratio fibrous crystalline cellulosic material to chalk in the fibrous crystalline cellulosic slurry is about 94.5 to 5.5. 
     In an embodiment, the final fibrous crystalline cellulosic slurry can be printed as longitudinally spaced apart banded regions, as described with respect to  FIG. 2 , to a base web  140  used to form banded wrapper paper  123  for smoking articles wherein the base web  140  has a nominal width ranging from about 36 inches (i.e., about 920 mm) to about 60 inches at the gravure printing press. In an embodiment, the moisture content of the base web  140  at the time of gravure printing is at least 3%. In an embodiment, the base web  140  is passed through a sprayer operable to spray water on the base web  140  before gravure printing to increase the moisture level of the base web  140  to at least 3%. 
     In an embodiment, the fibrous crystalline cellulosic slurry can be applied to the base web  140  at a target rate of about 5 to 50 BCM (billion cubic microns per square inch). In an embodiment, the fibrous crystalline cellulosic slurry can be applied to the base web  140  at a target rate of about 5 BCM to about 38 BCM. Thereafter the base web  140  can be dried so that the printing solution dries. In an example embodiment, the fibrous crystalline cellulosic slurry is gravure printed on the base web  140  in a single pass to form bands of fibrous crystalline cellulosic material  126  wherein the total dry weight of the added fibrous crystalline cellulosic material of each band is up to about 2.5 gsm. In an example embodiment, the fibrous crystalline cellulosic slurry is gravure printed on the base web  140  in a single pass to form bands of fibrous crystalline cellulosic material  126  wherein the total dry weight of the added fibrous crystalline cellulosic material of each band is about 2.5 gsm. In an example embodiment, the fibrous crystalline cellulosic slurry is gravure printed on the base web  140  in multiple passes to form bands having multiple layers of fibrous crystalline cellulosic material  126  wherein the total dry weight of the added fibrous crystalline cellulosic material is up to about 2.5 gsm. In an example embodiment, the fibrous crystalline cellulosic slurry is gravure printed on the base web  140  in multiple passes to form bands having multiple layers of fibrous crystalline cellulosic material  126  wherein the total dry weight of the added fibrous crystalline cellulosic material is about 2.5 gsm. In an example embodiment wherein the fibrous crystalline cellulosic slurry is gravure printed on the base web  140  in multiple passes, the base web  140  may be passed through a drier  634 , such as a heated can drier, to dry or partially dry the base web  140  between passes. 
     Once printed, the base web  140  can be passed through the drier  634  and advanced under tension to a slitter  635  where the nominal width of the base web can be longitudinally cut into a plurality of strips or ribbons, each strip having a width of about 27 mm (e.g., the width required to surround a conventional tobacco rod and have a longitudinal glue seam). While the base web  140  is still under tension, the plurality of strips can be simultaneously wound onto individual bobbins. 
     Ignition Propensity or IP is a standard test conducted as set forth in ASTM E 2187-04, “Standard Test Method for Measuring the Ignition Strength of Smoking Articles”, which is incorporated herein in its entirety by this reference thereto. Ignition propensity measures the probability that a smoking article, when smoldering and placed on a substrate, will generate sufficient heat to maintain smoldering of the tobacco rod. Low values for IP are desirable as such values correlate with a reduced likelihood that a smoldering smoking article, when inadvertently left unattended upon a substrate, will cause combustion in the substrate. An IP value of a smoking article should be no greater than about 25%, and preferably no greater than about 20%, and even more preferably no greater than about 10% as described in US Patent Application Publication No. 2013/0306082 published Nov. 21, 2013, the entire content of which is incorporated herein by reference thereto. 
     Self-Extinguishment or SE herein is a reference to smoldering characteristics of a smoking article under free burn conditions. To evaluate SE, a laboratory test is conducted at a temperature of 23° C.+−0.3° C. and relative humidity of 55%+−0.5%, both of which should be monitored by a recording hygrothermograph. Exhaust hood(s) remove combustion products formed during testing. Prior to testing, smoking articles to be tested are conditioned at 55%+−0.5% relative humidity and 23° C.+−0.3° C. for 24 hours. Just prior to testing, the smoking articles are placed in glass beakers to assure free air access. 
     SE testing takes place within an enclosure or test box. A single port smoking machine or an electric lighter is used to ignite the smoking articles for the test. During testing, an apparatus or “angle holder” holds the smoking articles to be tested by holding an end at angles of 0° (horizontal), 45°, and/or 90° (vertical). Preferably, twenty (20) smoking articles are tested at each of the 0°, 45°, and 90° positions. If more than one apparatus is used, the apparatuses are preferably positioned such that the smoking articles face away from each other to avoid cross interference. If a smoking article goes out before the front line of the smoldering coal reaches the tipping paper, the outcome is scored as “self-extinguishment”; on the other hand, if the smoking article continues smoldering until the front line of the smoldering coal reaches the tipping paper, then the outcome is scored as “non-extinguishment”. Thus, for example, an SE value of 95% indicates that 95% of the smoking articles tested exhibited self-extinguishment under free burn conditions; while an SE value of 20% indicates that only 20% of the smoking articles tested exhibited self-extinguishment under such free burn conditions. 
     The SE value for a smoking article should be no greater than about 80% (at horizontal orientation) and preferably no greater than about 50% and even more preferably no greater than about 25% as described in US Patent Application Publication No. 2013/0306082 published Nov. 21, 2013, the entire content of which is incorporated herein by reference thereto. It is desirable to achieve IP performance that meets and exceeds governmental requirements. Moreover, as also previously noted, that desired IP performance often adversely impacts the SE performance of the smoking article. Stated differently, while the IP performance may meet or exceed the governmental requirements, that IP performance is typically associated with a smoking article that will self-extinguish when hand held by a smoker—an SE of 100%. Since smokers ordinarily prefer not to need to relight a smoking article, improvement of SE performance while maintaining IP performance constitutes a highly desirable feature for improved wrappers. 
     To improve SE performance, certain example band configurations disclosed herein are useful in constructing smoking articles having both improved SE performance and desired IP performance. For example, a band  126  configuration such as shown in  FIG. 6  is capable of better sustaining smoldering during free burns, yet when placed adjacent a substrate, does not sustain smoldering. In addition, about 10% IP can be obtained for paper having diffusion ranging from about 0 to about 0.2 cm/sec, while maintaining about 18% SE, by controlling the print area and volume of fibrous crystalline cellulosic slurry printed on the base web  140 . 
     According to an example embodiment, as shown in  FIG. 6 , banded wrapper paper  123  can include a base web  140  which includes a plurality of bands of fibrous crystalline cellulosic material  126  on one or both sides thereof. In an example embodiment, the bands of fibrous crystalline cellulosic material  126  can be arranged on the base web  140  such that a smoking article  120  (see e.g.,  FIG. 1 ) including a piece of the banded wrapper paper  123  includes at least two bands of fibrous crystalline cellulosic material  126 , wherein each band of fibrous crystalline cellulosic material has a first zone  202 , a second zone  203 , and optionally a third zone  204  of fibrous crystalline cellulosic material wherein the amount of the fibrous cellulosic crystalline cellulosic material within each zone can be selected to control the IP performance and/or SE performance of a smoking article including the wrapper paper. In an example embodiment, the first zone  202  and the third zone  204  include about the same amount of fibrous crystalline cellulosic material on the base web  140 , while the second zone  203  has about 20% to about 80% (e.g., about 25% to about 75%, about 30% to about 70%, about 35% to about 65%, about 40% to about 60%, or about 45% to about 55%) less fibrous crystalline cellulosic material on the base web  140  than the first or third zones  202 ,  204 . 
     In an example embodiment, the fibrous crystalline cellulosic material of each zone is applied as a plurality of dots of fibrous crystalline cellulosic slurry arranged in a pattern, generally within the zone, to produce a banded region of fibrous crystalline cellulosic material on the base web  140 . Moreover, each dot of fibrous crystalline cellulosic slurry printed in the second zone  203  has smaller dimensions than each dot of fibrous crystalline cellulosic slurry printed in the first zone  202  and the third zone  204 .  FIG. 7  shows an example embodiment of a patterned portion of a gravure cylinder (roller)  610  that may be used to print banded regions of fibrous crystalline cellulosic slurry to form banded regions of fibrous crystalline cellulosic material  126  which have a first zone  202 , a second zone  203 , and a third zone  204  of fibrous crystalline cellulosic material. In an example embodiment, the first, second, and third zones  202 ,  203 ,  204  of each banded region  126  are directly adjacent to one another such that they are not separated by a length of base web  140  that is free of added fibrous crystalline cellulosic material. As shown in  FIG. 7 , the gravure roller  610  includes a plurality of cells  700  etched thereon in a pattern corresponding to the aforementioned zones  202 ,  203 ,  204  wherein the cells  700  have a generally hexagonal shape. In an example embodiment, the gravure cylinder  610  includes first and third zones  712  and a second zone  710  therebetween wherein walls  720  between adjacent cells  722  in the first and third zones  712  have a narrower width than walls  724  between adjacent cells  726  of the second zone  710 . Because the walls  724  between adjacent cells  726  of the gravure cylinder  610  used to form the dots of printed slurry in the second zone  203  are thicker, less fibrous crystalline cellulosic slurry is applied by the gravure roller  610  and the dots of printed slurry tend to stay separated once printed on the base web  140 . In contrast, dots of printed slurry in the first zone  202  and third zone  204  are formed by a gravure roller  610  including cells  722  having thinner walls  720  between adjacent cells  726 , such that a greater amount of fibrous crystalline cellulosic slurry is applied and the dots of printed slurry tend to run together when printed on the base web  140 . In an example embodiment, the walls  724  of the cells  726  may be configured such that the dots of printed slurry run together when printed on the base web  140 . In an example embodiment, the walls  720  between adjacent cells  726  of the first and/or third zones  202 ,  204  may be configured such that the dots printed thereby tend to stay separated once printed on the base web  140 . 
     In example embodiments, the first zone  202  and the third zone  204  can have a diffusivity ranging from about 0 to about 0.1 cm/sec (e.g. about 0.01 to about 0.09 cm/sec, about 0.02 to about 0.08 cm/sec, about 0.03 to about 0.07 cm/sec or about 0.04 to about 0.06 cm/sec), and the second zone  203  can have a diffusivity ranging from about 0.1 to about 0.4 cm/sec (e.g. about 0.15 to about 0.35 cm/sec or about 0.2 to about 0.3 cm/sec). 
     When the word “about” is used in this specification in connection with a numerical value, it is intended that the associated numerical value include a tolerance of +/−10% around the stated numerical value. Moreover, when reference is made to percentages in this specification, it is intended that those percentages are based on weight, i.e., weight percentages. 
     The terms and phrases used herein are not to be interpreted with mathematical or geometric precision, rather geometric terminology is to be interpreted as meaning approximating or similar to the geometric terms and concepts. For example, rounded or filleted corners are intended to be included in geometric shapes such as a rectangular, hexagonal, and the like. Terms such as “generally” and “substantially” are intended to encompass both precise meanings of the associated terms and concepts as well as to provide reasonable latitude which is consistent with form, function, and/or meaning. 
     It will now be apparent to those skilled in the art that this specification describes a new, useful, and nonobvious smoking article, wrapper therefor, and process for making the wrapper and smoking article. It will also be apparent to those skilled in the art that numerous modifications, variations, substitutes, and equivalents exist for various aspects of the smoking article, wrapper and process that have been described in the detailed description above. Accordingly, it is expressly intended that all such modifications, variations, substitutions, and equivalents that fall within the spirit and scope of the invention, as defined by the appended claims, be embraced thereby.