ES2683147T3 - Printing process for pattern wrapping paper - Google Patents

Abstract

A process for making patterned wrapping paper comprising the steps of: preparing a printing solution that includes at least water and an oxidized starch having: room temperature viscosity no greater than about 50 centipoise (50 mPa · s); particles in the range of about 4 to about 40 microns when dry and about 90% in the range of about 10 microns to about 100 microns when wet; and a pH in the range of about 6 to about 6.5, the starch which is further capable of forming a printing solution with about 20% to about 24% by weight of oxidized starch content and the printing solution having a surface tension of at least about 65 dynes per centimeter (6.5.10-2Nm-1); and providing a base weft of wrapping paper; apply the printing solution to the wrapping paper in a predetermined pattern.

Description

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DESCRIPTION

Printing process for wrapping paper with pattern Description field:

This description generally refers to a process for making cigarette wrapping paper that has an applied pattern of additional material. More particularly, the description refers to a process for making cigarette wrapping paper with a specially formulated oxidized starch material.

US 2007/0102017 is a prior art process for manufacturing a wrapper with a known pattern, the process that includes preparing a printing solution that includes at least water and an oxidized starch.

Summary

Cigarette wrapping paper can be made with an additional material pattern to reduce the propensity to ignition characteristics of a smoking article manufactured by using the wrapper. The reduced ignition propensity characteristics reflect a reduced ability of a smoking article to cause a substrate to ignite when a burning smoking article is accidentally left abandoned on a substrate.

According to this description, a predetermined pattern of additional material containing an aqueous solution of starch can be applied to a base weft of wrapping paper. The predetermined pattern may comprise a plurality of transverse bands, a plurality of longitudinal bands, a two-dimensional matrix of treated regions, or any other suitable pattern. Preferably, the predetermined pattern can be applied by using a printing technique, such as, for example, gravure printing, offset printing, inkjet printing, spraying, die printing, or the like. With maximum preference, gravure printing can be used.

To improve the ignition prone characteristics of a smoking article made from the wrapping paper, the pattern is preferably applied with a printing solution containing a rusty starch as set forth in claim 1. The desired printing characteristics they are achieved through the use of an aqueous solution of starch having a viscosity at room temperature not exceeding approximately 50 mPas (centipoise, cP), and is prepared from particles having a size in the range of about 4 microns to about 40 microns when dry, and about 90% of the particles that have a size in the range of about 10 microns to about 100 microns when wet. In addition, the starch solution is slightly acidic with a pH in the range of about 6 to about 6.5. The starch used for the printing solution can preferably be mixed with water to form a printing solution having a starch concentration of about 20% to about 24% (by weight). Another feature of the printing solution is a relatively high surface tension, for example, in the order of 6.5.10.2Nirr1 (65 dynes / centimeter) or more.

If desired, the printing solution can be applied to the base pattern in two or more layers. These layers can be registered vertically between sf, shifted between sf, have separate portions between sf, and the like. In addition, a conventional filler material, such as calcium carbonate, can be included in one or more of the layers, as desired.

Brief description of the figures:

Many objectives and advantages of this description will be apparent to those skilled in the art when this written description is read together with the accompanying drawings where the same reference numbers apply to similar elements and where:

Figure 1 is a schematic view of a gravure printing process;

Figure 2 is a schematic view of a wrapping paper having transversely printed regions;

Figure 3 is a schematic view of a wrapping paper having longitudinally printed regions;

Figure 4 is a schematic view of a wrapping paper having a two-dimensional pattern;

Figure 5 is a cross-sectional view of a multilayer printed region; Y

Figure 6 is a perspective view of a smoking article having a tobacco rod constructed with the wrap described in the present description.

Detailed description

Generally, a predetermined pattern of additional material can be applied to a base weft of a wrapping paper to obtain improved ignition-prone ("IP") characteristics and also to obtain

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improved self-extinguishing characteristics ("SE"). The propensity to ignition is a standard test carried out as set forth in ASTM E 2187--04, "Standard Test Method for Measuring the Ignition Strength of Smoking articles". The propensity to ignition measures the probability that a smoking article, when placed on a substrate, generates enough heat to maintain the static combustion of the tobacco rod. Low IP values are convenient since such values correlate with a lower chance of a burning smoking article causing combustion in an underlying substrate.

In addition, the predetermined pattern of additional material is typically applied to a base weft that has a permeability that is in the range of about 20 to about 80 CORESTA units. When dry, the additional material often forms a film on the base weave that is effective in locally reducing permeability to values in the range of 0 to about 10 CORESTA units. In some applications, the additional material is applied as an aqueous solution that includes starch.

Unexpectedly, it has been found that certain characteristics of the starch material give rise to predetermined patterns that produce very low values of propensity to ignition when the patterned base paper is formed in the smoking articles. Even more surprising has been the finding that within the standard specifications for some well-known starch materials, variations from batch to batch in material properties may affect the propensity to ignition of the resulting smoking articles. As an example, the specifications of a rusty tapioca starch commercially offered by National Starch & Chemical Co. as Flo-Max 8 indicate a pH in a 1% solution that is in the range of 4.5 to 6.5 , with particles that have molecular weights in excess of 10,000. Surprisingly, when a predetermined pattern was applied to a base frame with a lot of Flo-Max 8 having a pH in the range of about 6 to about 6.5, it has been found that the propensity to ignition has greatly improved compared with other lots of Flo-Max 8 for which the pH was less than about 6 but still within the manufacturer's specifications.

Various balances or compensations necessary in the selection of starch parameters should be performed for use in the application of films to the wrapping paper. For example, while high molecular weight starch may result in an effective reduction of permeability, such high molecular weight starches should be used in low concentrations, resulting in a solution having a very high water content. But high water films are much more difficult to dry effectively in the porous wrapping paper. In addition, it has been found that the surface tension of the starch solution affects the retention of small air bubbles - the low surface tension allows smaller bubbles to remain in the solution, while the high surface tension causes the bubbles to agglomerate and separate from the solution, providing a more uniform and consistent material for application to wrapping paper.

Although not fully understood, it is believed that the preferred pH range of the oxidized starch reflects a lower - or less complete - degree of oxidation of the starch polymer chains by providing longer polymer chains than the more acidic starches (i.e. , lower pH).

In addition, longer polymer chains produce a solution that has a higher viscosity. The higher viscosity for the starch solution results in better control when applied to a wrapping paper in a printing process.

Based on these understandings, it has been found that the marked improvement in the propensity for ignition of the pattern wrapping paper results in starch solutions having particular and improved characteristics. Those characteristics for an aqueous solution that includes oxidized starch include a pH in the range of about 6 to about 6.5; a surface tension of at least about 6.5.10'2Nm'1 (65 dynes / centimeter); a viscosity at room temperature of no more than about 50 mPa s; and a particle size distribution in the range of about 4 microns to about 40 microns for dry particles, with about 90% that are also in the range of about 10 microns to about 100 microns when wet. In addition, the particles preferably have a molecular weight so that the solution can have starch concentrations in the range of about 20% to about 24%. Preferably, the starch comprises an oxidized tapioca starch.

Aqueous starch solutions used for application to the base weft or wrapping paper are typically prepared by making a starch / water mixture by first mixing the desired weight of dry starch powder with the desired weight of water at room temperature (i.e. , at about 15 ° C to about 25 ° C) to obtain a starch / water mixture having the preselected concentration. For example, to prepare a starch / water solution with a preselected concentration of 20%, 20 parts by weight of starch are mixed with 80 parts by weight of water. The starch / water solution is then heated to a high sub-boiling temperature in the range of about 90 ° C to about 95 ° C - that is, below the boiling temperature. The starch / water solution is maintained at elevated temperature for approximately 20 to approximately 30 minutes for thermal immersion. Then, the starch / water solution

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It cools to room temperature. This cooling stage can be produced by heat transfer processes passively, such as naturally; or the cooling stage can be activated (or forced) such as by immersion in a cooling bath or by using a conventional mechanical cooling system. Throughout the mixing stage, the heating stage, the thermal immersion stage, and the cooling stage, the starch / water mixture are stirred. Stirring can be continuous or essentially continuous. If additional constituents, such as calcium carbonate, are to be incorporated into the starch / water solution, these constituents must be added after the starch / water solution returns to room temperature after the thermal immersion stage.

Aqueous starch solutions having the characteristics specified above and prepared in the manner described above can be applied to a base frame by using any of a multitude of printing techniques that include, by way of example and without limitation, the group that It consists of gravure printing, offset printing, inkjet printing, spraying, and die printing. Other printing processes may also be suitable and are intended to be within the teachings of this description. Preferably, however, gravure printing can be used to apply the starch solution to a base weft to obtain a pattern wrapping paper.

For example, (see Figure 1), a base weft of wrapping paper 10 can be fed from a reel 12 in a gravure printing system 14 where a predetermined pattern of starch solution prepared in accordance with the above description is Applies to the base frame 10. The base frame 10, with the newly applied predetermined pattern, is collected in a collection coil 16. In conventional steps in any other way, the pattern wrapping coil 16 can be used to make rods. of tobacco for use in the manufacture of smoking articles, such as cigarettes.

The gravure printing system 14 may include one, two, three, or more printer operations 14a, 14b, 14c. Since these operations are essentially the same, it will be sufficient to describe one's details with the understanding that others have the corresponding details. The starch solution described above can be supplied to a reservoir 20 from which it is pumped or supplied in any other way to an engraving roller 22 having a patterned surface. That roller 22 rotates in a bath of the starch solution. As the engraving roller 22 rotates, the starch solution is cleaned from the surface of the roller by a scraper assembly 23 so that, as the engraving roller 22 comes into contact with the base frame 10 at the point of grip between the engraving roller 22 and the elastically coated support roller 24, the starch solution is transferred to the base frame with the pattern on the surface of the engraving roller 22.

After proper drying, the base frame 10 can be advanced to one or more printing operations 14b, 14c where one or more additional layers of starch material can be applied in the same or different predetermined patterns to the base frame 10. If As desired, the starch material in other printing operations may include other constituents, for example, calcium carbonate. In addition, if desired, the starch solution having calcium carbonate could be applied in the first printing operation 14a, while the starch solution without calcium carbonate may be applied in the second or subsequent printing operation 14b, 14c.

The base frame 10 (see Figure 2) typically has a transverse direction or direction of the transverse frame (shown by arrow 30) as well as a longitudinal direction (shown by arrow 32). The predetermined pattern of additional material may comprise a plurality of generally parallel regions or bands, oriented transversely 34. These bands may be uniformly separated along the length of the base frame 10, or may be arranged in recurring separation patterns related to The length of the tobacco rod and finished cigarette manufacturing.

Alternatively, the base frame 10 may include a predetermined pattern such as one or more regions or lengths that extend longitudinally 36 (see Figure 3) of additional material. If desired, the predetermined pattern may also comprise a two-dimensional matrix of regions 38 (see Figure 4) of additional material separated along and / or transversely of the base frame 10.

In addition, as noted above, the additional material can be applied in two or more layers 40, 42 (see Figure 5). The layers can be fully registered and coextensive with each other if desired. Alternatively, the upper layer 42 may be divided or cut into two portions 42a, 42b, each of which overlaps the first or lower layer 40 so that there is a space between the two portions 42a, 42b. That space may extend either longitudinally or transversely over the base frame 10. In a further alternative, the upper layer 42 may be superimposed on the lower layer 40, but not coextensive with it.

A smoking article (see Figure 6) comprises a tobacco rod 205 and a filter 207, which are joined together with a nozzle paper 209. The tobacco rod 205 includes a wrapper 210 which is constructed in accordance with the teachings in This description.

When the word "approximately" is used in this description in relation to a numerical value, the associated numerical value is intended to include a tolerance of ± 10% approximately to the declared numerical value. Also, when referring to percentages in this description, the percentages are intended to be based on weight, that is, percentages by weight.

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It will now be clear that a new, improved and not obvious process for making pattern wrapping paper has been described in this description with sufficient particularity to be understood by one skilled in the art. In addition, it will be apparent to those skilled in the art that there are numerous modifications, variations, substitutions, and equivalents for the features of the invention that do not materially depart from the spirit and scope of the invention. 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 in the appended claims be included in the appended claims.

Claims (16)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 65 1. A process for making pattern wrapping paper comprising the steps of: preparing a printing solution that includes at least water and an oxidized starch having: viscosity at room temperature no greater than about 50 centipoise (50 mPas); particles in the range of about 4 to about 40 microns when dry and about 90% in the range of about 10 microns to about 100 microns when wet; Y a pH in the range of about 6 to about 6.5, the starch which is also capable of forming a printing solution with approximately 20% to approximately 24% by weight of oxidized starch content and the printing solution having a surface tension of at least approximately 65 dynes per centimeter (6.5.10 ' 2Nirr1); and provide a base weft of wrapping paper; apply the printing solution to the wrapping paper in a predetermined pattern. 2. A process in accordance with claim 1 wherein the base frame has a transverse direction and wherein the predetermined pattern comprises a plurality of bands generally extending transversely over the base frame. 3. A process according to claim 2 wherein the plurality of bands is regularly separated from each other along the base frame. 4. A process according to claim 1, 2 or 3 wherein the base frame has a longitudinal direction and wherein the predetermined pattern includes at least one longitudinally extending strip. 5. A process in accordance with any preceding claim wherein the base frame has a transverse direction and a longitudinal direction and wherein the predetermined pattern includes a plurality of regions transversely and longitudinally separated on the base frame. 6. A process in accordance with any preceding claim wherein the printing solution is applied in two or more layers to the base frame. 7. A process in accordance with any preceding claim wherein the printing solution also includes calcium carbonate. 8. A process in accordance with any preceding claim wherein the step of preparing a printing solution includes: mix a predetermined amount of dry starch with a predetermined amount of water at room temperature; heating the mixture of starch and water to a sub-boiling temperature; keeping the mixture of starch and water at the sub-boiling temperature for a period of time in the range of about 20 to about 30 minutes; allow the mixture of starch and water to return to room temperature; Y Stir the mixture of starch and water at least essentially continuously during the preparation stage. 9. A process according to claim 8 wherein the subbulb temperature is a temperature in the range of about 90 ° C to 95 ° C. 10. A process according to claim 8 or 9 wherein the step of allowing the mixture of starch and water to return to room temperature includes the active cooling stage. 11. A process according to claim 8 or 9 wherein the step of allowing the mixture of starch and water to return to room temperature includes the passive cooling stage. 12. A process according to claim 8, 9, 10 or 11 which further includes the step of adding at least one additional constituent to the starch and water mixture after the mixture returns to room temperature. 13. A process according to claim 12 wherein the additional constituent is calcium carbonate. 14. A process in accordance with any preceding claim wherein the starch comprises an oxidized tapioca starch. 15. A process for manufacturing a tobacco rod for a smoking article comprising pattern wrapping paper, comprising the steps of: manufacture a pattern wrapping paper by a process in accordance with any previous claim; Y 5 use said patent wrap to make a tobacco rod. 16. A process for manufacturing a smoking article comprising manufacturing a tobacco rod by a process in accordance with claim 15 and joining said tobacco rod to a filter with a nozzle paper. image 1 Figure 1 20 14th 14b 14c image2 image3 image4 Figure 2 image5 Figure 3 Figure 4 42b 42nd image6 10 yyyyyyyyy / yy Figure 5 image7