RU2458608C2 - Printing method for wrapping paper with pattern - Google Patents

Abstract

FIELD: printing.

SUBSTANCE: invention relates to a method of obtaining wrapping paper with pattern, which includes the following steps: preparing a printed solution containing at least water and oxidised starch, having a viscosity at room temperature of no more than approximately 50 cP (50 mPa/sec); particles with sizes in the range from about 4 to about 40 microns in the dry state and about 90% of the particles with sizes in the range of from about 10 microns to about 100 microns when wet; and the pH value in the range from about 6 to about 6.5; starch, in addition, is able to form a solution containing oxidised starch from about 20% to about 24%; the printing solution has a surface tension of not less than about 65 dynes per centimeter (6.5×10^-2 A.S.L.); and creation of a basis tape from the wrapping paper; applying of printed solution on the wrapping paper with a given pattern.

EFFECT: reduction of characteristics of risk of flame formation of smoking product.

Description

FIELD OF THE INVENTION

This invention relates generally to a method for manufacturing cigarette wrapping paper having a printed pattern of additive material. More specifically, the invention relates to a method for manufacturing cigarette wrapping paper with specially prepared oxidized starch material.

SUMMARY OF THE INVENTION

Cigarette wrapping paper may be formed with a pattern of additive material to reduce the risk of fire of a smoking article formed using wrapping paper. The reduced fire risk characteristics reflect a reduced ability of the smoking article to ignite the substrate when the smoldering smoking article is left accidentally without supervision on the substrate.

According to this invention, a predetermined pattern of the material of the additive containing the starch aqueous solution can be applied to the wrapping paper base tape. A given pattern may comprise a plurality of transverse strips, a plurality of longitudinal strips, a two-dimensional matrix of machined sections, or any other suitable pattern. Preferably, the predetermined pattern can be applied using a printing method such as intaglio printing, offset printing, inkjet printing, spraying and matrix printing or the like. Most preferably, gravure printing can be used.

To enhance the risk of fire of a smoking article formed from brown paper, the pattern is preferably applied using a printing solution containing oxidized starch. Preferred printing characteristics can be achieved by using an aqueous starch solution having a viscosity at room temperature of not more than about 50 mPa / s (centipoise, cP) and made from particles ranging in size from about 4 microns to about 40 microns in dry condition and from about 90% of the particles having sizes in the range of from about 10 microns to about 100 microns in the wet state. In addition, it is also desirable that the starch solution be 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 from about 20% to about 24% (mass). Other preferred characteristics of the printing solution are relatively high surface tension, for example of the order of 6.5 · 10 ^-2 N / m (65 dyne / centimeter) or more.

If desired, the printing solution can be applied to the base tape in two or more layers. These layers can be aligned vertically with each other, with a shift of one in relation to the other, having parts located at a certain distance from each other, and the like. In addition, if desired, a conventional excipient, such as calcium carbonate, may be added to one or more layers.

Brief Description of the Drawings

Many of the objectives and advantages of this invention will be apparent to those skilled in the art upon reading this description along with the accompanying drawings, where like reference numbers apply to like elements and where:

Figure 1 is a schematic view of a deep printing method;

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

Figure 3 is a schematic view of a wrapping paper having longitudinally imprinted areas;

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

Figure 5 is a sectional view of a multilayer printing region; and

FIG. 6 is a perspective view of a smoking article having a tobacco rod constructed with the wrapping paper described herein.

Detailed description

Typically, a predetermined pattern of the additive material can be applied to the tape of the base of the wrapping paper to achieve enhanced fire risk characteristics ("IP"), as well as to achieve enhanced self-extinguishing characteristics ("SE"). Fire risk is a standard test carried out according to ASTM E 2187-04, “Standard Test Method for Measuring the Ignition Strength of Smoking Articles”, which is incorporated herein by reference in its entirety. The risk of fire measures the likelihood that a smoking article, when placed on a substrate, will produce enough heat to keep the tobacco rod burning continuously. Low IP values are desirable since these values correlate with a reduced likelihood that a smoldering smoking article will cause combustion in a substrate below it.

In addition, a predetermined pattern of the additive material is usually applied to the base tape having a permeability ranging from about 20 to about 80 CORESTA units. In the dry state, the additive material often forms a film on the base tape, which is effective in locally reducing permeability to values ranging from 0 to about 10 CORESTA units. In some applications, the additive material is applied as an aqueous solution containing starch.

Unexpectedly, it was found that the usual characteristics of the starch material form predetermined patterns that give very low risk of fire when a paper base is formed on smoking articles on which the pattern is applied. Even more unexpected was the fact that, within the standard specifications for some well-known starch materials, differences between different loads can affect the risk of fire for the resulting smoking articles. By way of example, specifications for oxidized tapioca starch commercially available from National Starch & Chemical Co. like Flo-Max 8, they show in a 1% solution a pH value in the range from 4.5 to 6.5, with particles having molecular weights higher than 10000. Unexpectedly, when a given pattern was applied to the base tape using a Flo- Max 8, with a pH ranging from about 6 to about 6.5, the risk of fire was found to be much higher than other Flo-Max 8 downloads, for which the pH was less than about 6, but still within the specifications manufacturer.

Various mutual balancing or compromises must be made when selecting starch parameters for use in films for application onto brown paper. For example, since a high molecular weight of starch can cause a decrease in effective permeability, such high molecular weight starches should be used at low concentrations, resulting in a solution having a very high moisture content. But films with a high moisture content are much more difficult to dry efficiently on porous brown paper. In addition, it was found that the surface tension of the starch solution causes the retention of small air bubbles — low surface tension allows smaller bubbles to remain in the solution, while high surface tension causes the bubbles to accumulate and separate from the solution, giving a more uniform and stable material for application on brown paper.

Although this is not fully understood, the preferred pH range of oxidized starch is believed to reflect a lower — or less complete — oxidation state of starch polymer chains giving longer polymer chains than more acidic (i.e., lower pH) starches. In addition, longer polymer chains result in a solution having a higher viscosity. The higher viscosity of the starch solution corresponds to better control when applied to wrapping paper during the printing process.

Based on this knowledge, it was found that a noticeable improvement in the risk of fire for patterned wrapping paper occurs for starch solutions having specific and improved characteristics. These characteristics for an aqueous solution containing oxidized starch include a pH in the range of about 6 to about 6.5; a surface tension of not less than about 6.5 · 10 ^-2 N / m (65 dyne / centimeter); viscosity at room temperature of not more than about 50 mPa / s and particle size distribution in the range from 4 microns to 40 microns for particles in the dry state, while the sizes of about 90% of the particles also range from about 10 microns to about 100 microns in the wet state. In addition, the particles preferably have a molecular weight such that the solution can have starch concentrations in the range of about 20% to about 24%. Preferably, the starch includes oxidized tapioca starch.

Aqueous starch solutions used for applying to a base tape or wrapping paper are usually prepared by preparing a starch / water mixture by first mixing the desired mass of dry starch powder with the desired mass of water at room temperature (i.e., from about 15 ° C to about 25 ° C) to obtain a starch / water mixture having a predetermined concentration. For example, in order to prepare a starch / water solution with a predetermined 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 an elevated temperature without boiling, in the range of about 90 ° C to about 95 ° C — that is, below the boiling point. The starch / water solution is kept at an elevated temperature for about 20 to about 30 minutes for thermal impregnation. Then the starch / water solution cools to room temperature. This cooling step can occur passively, for example using natural methods of heat transfer; or the cooling step may be active (or forced), such as immersion in a cooling bath or using a conventional mechanical cooling system. In the mixing step, the heating step, the thermal impregnation step and the cooling step, the starch / water mixture is mixed. Mixing may be continuous or substantially continuous. If additional components, such as calcium carbonate, are added to the starch / water solution, these components must be added after the starch / water solution returns to room temperature after the thermal impregnation step.

Aqueous starch solutions having the above characteristics and prepared as described above can be applied to the base ribbon using a variety of printing technologies, including, for example and without limitation, a group comprising intaglio printing, offset printing, inkjet printing, spraying and matrix printing. Other printing methods may also be usable and are intended to be within the concept of the present description. Preferably, however, gravure printing can be used to apply the starch solution to the base ribbon to form a wrapping paper with a pattern.

For example (see FIG. 1), the wrapping paper base tape 10 can be fed from the bobbin 12 to the intaglio printing system 14, where a predetermined starch solution pattern obtained in accordance with the above description is applied to the base tape 10. The base tape 10 s only that the applied pattern is assembled on the assembly reel 16. In other conventional steps, the reel wrapper 16 with a pattern can be used to form tobacco rods for use in the manufacture of smoking articles such as cigarettes.

The intaglio printing system 14 may include one, two, three or more printing operations 14a, 14b, 14c. Since these operations are essentially the same, it will suffice to describe the details of one of them, realizing that the others have corresponding details. The starch solution described above can be fed into the reservoir 20, from which it is pumped or in some other way fed to the gravure roller 22 having a surface with a pattern. This roller 22 rotates in a starch solution bath. During rotation of the intaglio drum 22, the starch solution is removed evenly from the drum surface using the metering blade assembly 23 so that the intaglio roller 22 comes into contact with the base ribbon 10 in the contact zone between the intaglio roller 22 and the support roller 24 elastically mounted opposite , the starch solution is transferred to the base tape using a structure with a pattern on the surface of the gravure drum 22.

After necessary drying, the base ribbon 10 can be fed into one or more printing operations 14b, 14c, where one or more additional layers of starch material with the same or different predetermined patterns can be applied to the base ribbon 10. If desired, the starch material in subsequent operations The printing may contain other components, for example calcium carbonate. In addition, if necessary, a starch solution containing calcium carbonate could be applied in the first printing operation 14a, although a starch solution without calcium carbonate could be applied in the second or subsequent printing operations 14b, 14c. The tape of the base 10 (see Figure 2) usually has a transverse, or weft, direction (shown by arrow 30), as well as a longitudinal direction (shown by arrow 32). The predetermined pattern of the additive material may contain many transversely oriented, mainly parallel, regions or strips 34. These strips can be located equally along the length of the main tape 10 or can be arranged in the form of repeating patterns separated by a certain space corresponding to the length of the tobacco rod and to obtain finished cigarettes.

Alternatively, the base tape 10 may comprise a predetermined pattern, such as one or more longitudinally extending regions or bands 36 (see FIG. 3) of the additive material. If necessary, the specified pattern may also contain a two-dimensional group of sections 38 (see Figure 4) of the additive material located along and / or across the ribbon of the base 10.

In addition, as indicated above, the additive material can be applied to two or more layers 40, 42 (see Figure 5). If necessary, the layers can be fully combined and coincide with each other. Alternatively, the upper layer 42 can be divided or cut into two parts 42a, 42b, each of which is superimposed on the first or lower layer 40 so that there is some space between the two parts 42a, 42b. This space may extend along or across the ribbon of the base 10. As an additional alternative, the outer layer 42 may be superimposed on the lower layer 40, but not coincide with it completely.

The smoking article (see FIG. 6) comprises a tobacco rod 205 and a filter 207 that are connected to each other by wrapping paper 209. The tobacco rod 205 contains wrapping paper 210, which is constructed in accordance with the present concept.

When the word “about” is used in this specification with respect to a numerical value, it is understood that the corresponding numerical value contains a tolerance of ± 10% around the indicated numerical value. In addition, when percentages are mentioned in this specification, it is understood that these percentages are by weight, that is, are by weight percent.

It will be obvious that in the present description a new, improved and non-obvious method of manufacturing a wrapping paper with a pattern is described in sufficient detail for its understanding by specialists in this field. In addition, it will be understood by those skilled in the art that there are numerous modifications, variations, substitutions, and equivalents of features of the present invention that do not deviate substantially from the spirit and scope of the present invention. Accordingly, it is expressly assumed that all such modifications, variations, substitutions, and equivalents that are within the spirit of the invention and fall within its scope, as defined by the appended claims, should be embraced by the appended claims.

Claims (15)

1. A method for producing wrapping paper with a pattern, comprising the steps of: preparing a printing solution containing at least water and oxidized starch, having a viscosity at room temperature of not more than about 50 cP (50 mPa / s); particles with sizes ranging from about 4 to about 40 microns in the dry state and about 90% of particles with sizes in the range of from about 10 microns to about 100 microns in the wet state; and a pH in the range of about 6 to about 6.5; starch, in addition, is able to form a solution with an oxidized starch content of from about 20% to about 24%; the printing solution has a surface tension of at least about 65 dyne per centimeter (6.5 · 10 ^-2 N / m); and creating a base tape of wrapping paper; applying a printing solution to wrapping paper with a given pattern. 2. The method according to claim 1, in which the base tape has a transverse direction and in which the specified pattern contains many strips that extend generally in the transverse direction on the base tape. 3. The method according to claim 2, in which the plurality of strips are located at the same distance from each other along the main tape. 4. The method according to claim 1, in which the base tape has a longitudinal direction and in which the specified pattern contains at least one longitudinally extending tape. 5. The method according to claim 1, in which the base tape has a transverse direction and a longitudinal direction, and in which the specified pattern contains many areas located across and along the base tape. 6. The method according to claim 1, in which the printing solution is applied to the base tape in two or more layers. 7. The method according to claim 1, in which the printing solution further comprises calcium carbonate. 8. The method according to claim 1, in which the stage of preparation of the printing solution includes: mixing a certain amount of dry starch with a certain amount of water at room temperature; heating a mixture of starch and water without boiling; maintaining the mixture of starch and water at an elevated temperature, without boiling, for a period of time ranging from about 20 to about 30 minutes; allowing the starch-water mixture to return to room temperature, and mixing the starch-water mixture at least substantially continuously during the cooking step. 9. The method of claim 8, in which the elevated temperature, at which boiling has not yet occurred, is a temperature in the range of from about 90 ° C to 95 ° C. 10. The method of claim 8, wherein the step of allowing the mixture of starch and water to return to room temperature includes an active cooling step. 11. The method of claim 8, wherein the step of allowing the starch and water mixture to return to room temperature includes a passive cooling step. 12. The method of claim 8, further comprising the step of adding at least one additional component to the mixture of starch and water after the mixture returns to room temperature. 13. The method according to item 12, in which the additional component is calcium carbonate. 14. The method according to any one of claims 1 to 13, in which the starch includes oxidized tapioca starch. 15. A smoking article comprising a tobacco rod, said tobacco rod comprising a wrapping paper constructed in accordance with the method of any one of claims 1-14.

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