HK1240292B - Cigarette wrapping paper, and a paper-wrapped cigarette using said cigarette wrapping paper - Google Patents

Description

Tobacco paper and cigarette using the same

Technical Field

The present invention relates to tobacco wrapping paper and cigarettes using the tobacco wrapping paper.

Background Art

Cigarettes sometimes have "stains" on the wrapping paper of the tobacco shreds wrapped in the cigarette rod, which detracts from the appearance. Therefore, there is a demand for a technology that prevents stains from occurring on the wrapping paper of cigarettes.

The main cause of tobacco paper stains is believed to be the leakage of tobacco-containing substances through the tobacco paper at the point of contact between the tobacco paper and the shredded tobacco during storage. Furthermore, with the recent increase in cigarette products containing large amounts of flavorings in the shredded tobacco, these flavorings may leak through the tobacco paper, causing stains.

Patent Document 1 describes that staining of tobacco wrapping paper is suppressed by placing an inner wrapping paper having a specific air permeability between tobacco constituting the cigarette and its outer wrapping paper. Patent Document 1 describes the basis weight of the inner wrapping paper as being a maximum of 30 g/m ² .

Patent Document 2 describes a method for suppressing stains on tobacco paper by applying a water-repellent agent made of a cellulose derivative to the paper and drying it to form a first layer, and then applying a cellulose derivative on top of the first layer to form a second layer.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 3-151867

Patent Document 2: U.S. Patent Publication No. 2004/0159414

Summary of the Invention

Problems to be solved by the invention

In the invention described in Patent Document 1, two types of tobacco wrapping papers, an outer wrapping paper and an inner wrapping paper, must be used. This poses a problem from the perspectives of cigarette productivity and cost, and maintaining the flavor of the cigarette.

The invention described in Patent Document 2 is characterized by applying a water-repellent agent, such as a cellulose derivative, twice to the tobacco paper. While applying such a substance is effective in suppressing staining, achieving a sufficient effect requires a large amount of application, significantly affecting the flavor quality, burnability, and breathability of the cigarette, thereby sometimes compromising the design freedom of the cigarette.

Therefore, it can be considered that there is still room for improvement in the conventional technology used from the viewpoint of suppressing the occurrence of stains on tobacco papers.

In view of the above circumstances, an object of the present invention is to provide a tobacco paper that suppresses the generation of stains.

Methods for solving problems

The present inventors conducted extensive research and concluded that tobacco paper staining results from the migration of stain-causing components contained in shredded tobacco along the fibrils of developed pulp fibers. Further research revealed that tobacco paper made from pulp having an average fiber length and freeness within a specific range, and having an average thickness within a specific range, can address this issue, leading to the present invention. In particular, the combination of average fiber length and freeness defined in the present invention differs significantly from the ranges typically found in pulp used in tobacco paper production.

That is, the present invention is as follows.

[1] A tobacco wrapping paper for wrapping shredded tobacco, the tobacco wrapping paper being made from pulp having an average fiber length of 1200 to 1700 μm and a water freeness of 30 to 65° SR, and having an average thickness of 45 to 100 μm.

[2] The tobacco wrapping paper according to [1] is obtained by making paper from pulp having an average fiber length of 1300 to 1700 μm and a water filterability of 35 to 57°SR, the average thickness of the wrapping paper being 45 to 60 μm and the air permeability being 24 to 110 Coresta units.

[3] The tobacco paper according to [1] or [2], wherein a film-forming material is added to the surface in contact with the shredded tobacco.

[4] A cigarette comprising shredded tobacco and tobacco paper for wrapping the shredded tobacco, wherein the tobacco paper is the tobacco paper according to any one of [1] to [3].

[5] The cigarette according to [4], wherein the shredded tobacco contains flavoring, and the content of flavoring is 7.5 mg/rod or more.

[6] The cigarette according to [5], wherein the flavoring is menthol.

Effects of the Invention

According to the present invention, it is possible to suppress the occurrence of stains on tobacco paper.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph illustrating the relationship between the average thickness of tobacco wrapping paper and the stain generation rate.

FIG. 2 is a graph showing the relationship between the freeness and average fiber length of pulp used for papermaking of tobacco paper and the evaluation of the stain reduction rate.

DETAILED DESCRIPTION

Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the following embodiments and examples, and can be implemented with modifications as desired without departing from the spirit of the present invention.

In the present invention, tobacco wrapping paper refers to wrapping paper for wrapping shredded tobacco constituting cigarettes, and does not refer to wrapping paper for wrapping filters.

The tobacco paper of the present invention is made by making pulp having an average fiber length of 1200 to 1700 μm and a water freeness of 30 to 65° SR, and has an average thickness of 45 to 100 μm.

By using pulp having an average fiber length of 1200 to 1700 μm and a freeness of 30 to 65° SR for papermaking and setting the average thickness of the resulting wrapping paper to 45 to 100 μm, it is possible to suppress the occurrence of stains on tobacco wrapping paper.

As for one of the reasons, the inventors believe that by using the above-mentioned specific pulp for papermaking and making the tobacco paper have an average thickness within a specific range, the fibril structure of the pulp fibers in the tobacco paper becomes unsuitable for the migration of stain-generating components through the fibrils, which helps to suppress stains.

The average fiber length of the pulp is more preferably 1300 to 1700 μm, and the freeness is more preferably 35 to 57° SR.

Here, the average fiber length of the present invention refers to the length-weighted average value of the fibers contained in the pulp used, and is the value measured by optical automatic analysis (JIS P8226-2) using unpolarized light with a fiber count of 20,000 or more. Furthermore, the freeness of the pulp of the present invention refers to the value measured by the Schopper-Riegler method (JIS P8121). It is believed that by setting the average fiber length and freeness within the above ranges, the growth of fine fibrils can be suppressed compared to conventional tobacco wrapping papers, resulting in less migration of stain components from the inner paper surface, which contacts the shredded tobacco, to the outer paper surface.

The average thickness of the tobacco paper of the present invention is a value measured by the method specified in JIS P 8118.

The pulp used in making the tobacco paper of the present invention is not particularly limited, and examples thereof include pulp made from hemp (flax) or wood, or a mixture of pulps made from these raw materials. Specifically, flax pulp is mentioned.

By changing the digestion and beating conditions when preparing the pulp to be used, the average fiber length and freeness can be adjusted.

As the conditions for steaming and beating, known conditions can be adopted.

The tobacco paper of the present invention may be made by, but is not particularly limited to, a wet papermaking method, wherein the wet papermaking method comprises dispersing components including the above-mentioned pulp in water to prepare a slurry, and making paper from the slurry using a wet papermaking machine.

The tobacco paper of the present invention may also contain a filler.

As the filler, calcium carbonate can be exemplified.

The tobacco paper of the present invention has an average thickness of 45 to 100 μm. To prevent bleeding from the inner to outer surfaces of the tobacco paper, the thicker the tobacco paper, the longer the distance between the front and back surfaces. This effectively prevents staining and ensures the strength of the tobacco paper. A preferred average thickness is 45 to 60 μm.

The average thickness of the tobacco wrapping paper can also be adjusted by adjusting the basis weight as described later, calendering as described later, and the like.

In one embodiment, the tobacco paper of the present invention has a basis weight of 25 to 40 gsm (g/m ² ). Such a basis weight helps maintain the strength of the tobacco paper and the flavor of the cigarette.

The basis weight of the tobacco paper can be adjusted by adjusting the pulp content and filler content or by adjusting the processing conditions of the wet papermaking machine.

It should be noted that the tobacco paper of the present invention may contain other additives within a range that does not impair the effects of the present invention. Examples of other additives include combustion aids.

Examples of the combustion aid include hydroxy acid salts, such as salts of citric acid, malic acid, and tartaric acid, and examples of these salts include sodium salts and potassium salts.

From the viewpoint of appropriately maintaining the combustion performance of the cigarette, the content of the combustion aid may be 0.1 to 5% by weight, preferably 0.5 to 2% by weight, relative to the weight of the tobacco paper.

The tobacco paper of the present invention may have a coresta unit of 24 to 110, as long as it does not affect the manufacturing and design freedom of the cigarette.

The air permeability in the present invention refers to the air flow rate per 1 cm ² per minute when air is passed through one side (2 cm ² ) of paper at a constant pressure of 1 kPa.

The tobacco paper of the present invention can be processed using a film-forming material on the surface that contacts the shredded tobacco. Known materials can be used as such film-forming materials, including, for example, alginic acid and its salts (e.g., sodium salt), pectin, polyvinyl alcohol, cellulose derivatives such as ethyl cellulose, methyl cellulose, and carboxymethyl cellulose, and starch and its derivatives (e.g., ether derivatives such as carboxymethyl starch and hydroxyalkyl starch, and ester derivatives such as starch acetate, starch phosphate, and starch octenyl succinate).

These film-forming materials are usually used in the form of a 1.0 to 30.0 wt % aqueous solution, which can be applied by printing the aqueous solution on the surface in contact with the tobacco shreds using an appropriate printing method such as gravure printing and, if necessary, on the opposite surface.

After application, the coating is dried by a known appropriate method to form a film made of the material so as to block specific locations on the paper, specifically, to block pores between fibers forming the paper, or along the fibers.

Such coating can significantly reduce the occurrence of stains on the tobacco paper.

This coating amount can be even less than that used in the prior art (e.g., 0.1-0.3 gsm). Conventional wrapping paper requires a higher coating amount, which inevitably affects combustibility and cigarette flavor quality. However, by coating the raw paper of the present invention with a film-forming material, a synergistic stain reduction effect is achieved. Therefore, by applying a small amount of film-forming material, the impact on cigarette quality can be minimized while achieving a superior stain reduction effect.

In addition, there is no particular limitation on the shape of the coating. When the coating is performed using the printing method described above, a more excellent stain reduction effect can be obtained by coating the entire surface.

The tobacco wrapping paper of the present invention can be wrapped with shredded tobacco in the same manner as conventional wrapping papers.

The cigarette of the present invention comprises shredded tobacco and tobacco wrapping paper for wrapping the shredded tobacco. The tobacco wrapping paper is the tobacco wrapping paper of the present invention described above.

As the tobacco cut into pieces, known tobacco cut into pieces can be used, and the filling amount of the tobacco cut into pieces can be generally 0.1 to 0.9 g/cm ^3. In addition, the cigarette of the present invention may have a filter portion, and as the filter portion, known cellulose acetate filters, paper filters, etc. can be used.

In the cigarette of the present invention, the cut tobacco may further contain flavorings. Examples of flavorings that may be optionally contained in the cut tobacco include phenolic compounds such as vanillin, ethyl vanillin, methyl salicylate, eugenol, isoeugenol, thymol, and propenyl ethyl guaiacol; cyclic and acyclic enol compounds such as maltol, ethyl maltol, methylcyclopentenone, and α-ketofuran; and oily flavorings such as cyclic and acyclic aliphatic alcohols such as menthol.

The content of the above-mentioned flavoring is preferably 7.5 mg/cigarette or greater. Even with the above-mentioned flavoring content, the cigarettes of the present invention can suppress staining. This increases the freedom of cigarette product design and productivity.

It should be noted that the upper limit of the flavor content is not particularly limited as long as it is an amount that can be contained in cigarettes.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the description of the following Examples unless it exceeds the gist of the present invention.

<Test Example 1: Examples 1 to 6, Comparative Examples 1 to 3>

Flax pulp having the average fiber length and water filterability shown in Table 1 was used for papermaking, and tobacco papers were produced with the average thickness and weight per unit area adjusted to the values listed in Table 1. The average fiber length and water filterability were adjusted by changing the conditions of steaming and beating, and the average thickness was adjusted by changing the weight per unit area of the tobacco papers or by applying a calendering treatment. The items shown in Table 1 were obtained using these tobacco papers. It should be noted that in Table 1, the tensile strength, air permeability, and stain generation rate were determined using the following method. In addition, the experimental results shown in Table 1 are shown in FIG1 as a graph showing the relationship between the average thickness of the tobacco papers and the stain generation rate.

In addition, the tobacco rolling papers of Comparative Examples 1 to 3 are of the specifications used as ordinary tobacco rolling papers.

<How to calculate the stain generation rate>

Flavored (menthol) tobacco was wrapped in various tobacco wrapping papers to produce cigarettes (cigarette rod length: 68 mm, diameter: 7.9 mm, American blend tobacco, fill density: 0.21 g/ ^cm³ , flavoring: 7.8 mg/cigarette). These cigarettes were then placed in a 20-cigarette paper container and stored in a sealed state at 22°C and 60% relative humidity for 28 days. The staining rate was then determined based on the following evaluation criteria. Given that tobacco paper staining is caused by the leakage of certain components in the tobacco or flavorings added to the tobacco into the tobacco wrapping paper, the staining rate is affected by the type and fill density of the tobacco filled into the cigarettes, as well as the type and amount of flavorings added to the tobacco. In this experiment, these tobacco and flavoring conditions were standardized and the experiment was conducted.

A single cigarette was defined as one with three or more stains with a maximum diameter of 1 mm or more, or one or more stains with a maximum diameter of 3 mm or more. A total of 200 cigarettes were observed, and the stain rate was the ratio of the number of stained cigarettes to the total number of cigarettes.

For stain evaluation, a stain rate of less than 35% was defined as "○...effective," a stain rate of 35% or higher but less than 45% was defined as "△...slightly effective," and a stain rate of 45% or higher was defined as "×...ineffective." As mentioned above, the stain rate is affected not only by the specifications of the tobacco paper but also by the conditions of the shredded tobacco and flavoring. Therefore, to simplify the evaluation, the improvement in the stain rate relative to conventional tobacco paper was evaluated.

<Determination of tensile strength>

The tensile strength of each tobacco paper was determined based on JIS P 8113, “Paper and paperboard—Test methods for tensile properties,” at a width of 15 mm.

<Measurement of air permeability>

The air permeability was measured using PPM1000 manufactured by FILTRONA.

Table 1

The "calendering" and "surface coating" in Table 1 were performed by the following steps.

Calendering

The tobacco paper of Comparative Example 4 was obtained by calendering the tobacco paper of Example 2 using a calendering apparatus. The apparatus comprises a calendering roller and a press roller, with the press roller facing the calendering roller and applying a predetermined linear pressure, specifically, 5.9 N per mm. Calendering can be performed by passing the tobacco paper between the calendering roller and the press roller. Calendering generally reduces the average thickness of the tobacco paper and its air permeability.

＜Surface coating＞

A low-methoxy pectin solution (1.8% by weight) with an esterification degree of 6-12 was applied to the entire surface of one side of the tobacco paper using a simple gravure coater. The tobacco paper of Comparative Example 3 was coated with 0.2 gsm of pectin on the tobacco paper of Comparative Example 2. Separately, the tobacco paper of Example 3 was coated with 0.2 gsm of pectin on the tobacco paper of Example 2. The coating speed was set at 4 m/min. In both Comparative Example 3 and Example 3, the pectin solution was applied only to the inner side of the cigarette when rolled.

After coating, the coating was dried at 90 to 95°C as heating conditions.

Examples 1 and 6 compare tobacco papers with different fillers, all of which have the same three primary physical properties (average fiber length, freeness, and average thickness)—the three key physical properties of interest to the present invention. As long as these three primary physical properties are the same, the stain generation rate is comparable even with different fillers. Therefore, it is believed that fillers have no effect on the stain generation rate.

A comparison of Example 6 and Comparative Example 2 reveals that, among the three key physical properties of interest in the present invention—average fiber length, freeness, and average thickness—the stain generation rate differs only when freeness differs significantly. Comparative Example 2, with a freeness of 70° SR, exhibits a stain generation rate of 56%, compared to 28% for Example 1, with a freeness of 57° SR.

A comparison between Example 2 and Comparative Example 4 reveals that the three key physical properties of tobacco paper, average fiber length, freeness, and average thickness, which are of interest to the present invention, vary depending on whether or not the paper is calendered. This comparison reveals that the staining rate differs only when the average thickness varies significantly. The staining rate for Comparative Example 4, with a thickness of 35 μm, is 85%, compared to 15% for Example 2, with an average thickness of 55 μm.

A comparison of Examples 1 and 4 reveals that, among the three key physical properties of interest in the present invention, average fiber length, freeness, and average thickness, varying the basis weight of tobacco paper results in varying average thickness. This comparison reveals that the staining rate differs only when the average thickness varies significantly. The staining rate in Example 4, with an average thickness of 47 μm, was 41%, compared to 28% in Example 1, with an average thickness of 52 μm.

Comparative Example 3 was obtained by applying a small amount of surface coating to the tobacco paper of Comparative Example 2. The average fiber length, freeness, and average thickness were essentially the same. Furthermore, Example 3 was obtained by applying a small amount of surface coating to the tobacco paper of Example 2. The average fiber length, freeness, and average thickness were essentially the same. For the tobacco paper (Comparative Example 2), which had a high stain incidence rate before surface coating, even a small amount of surface coating had little effect on reducing stain incidence. In contrast, for the tobacco paper (Example 2), which had a low stain incidence rate before surface coating, a small amount of surface coating significantly reduced stain incidence.

<Test Example 2>

Flax pulp (average fiber length: 1460 μm, freeness: 45° SR) was dispersed in water to prepare a slurry of 0.7 wt. %. This slurry was wet-processed using a Fourdrinier paper machine and then dehydrated and dried to obtain tobacco wrapping paper having an average thickness of 58.1 μm and a basis weight of 32.9 gsm.

Furthermore, by varying the cooking and beating conditions of the flax pulp described above, various grades of flax pulp with varying average fiber length and freeness were produced. Using these flax pulps, paper was made to maintain an average thickness that did not significantly vary from the aforementioned 58.1 μm, resulting in various grades of tobacco wrapping paper. The average thickness ranged from 51.0 to 58.1 μm.

Flavored shredded tobacco was wrapped in various grades of tobacco paper to produce cigarettes (cigarette rod length: 68 mm, diameter: 7.9 mm, shredded American blend, fill density: 0.20 g/ ^cm³ , flavoring: 7.5 mg/cigarette). 20-cigarette paper containers were filled with these cigarettes and stored sealed at 22°C and 60% relative humidity for 28 days. Staining was evaluated based on the following evaluation criteria to determine the staining rate.

The stain rate [%] was calculated in the same manner as in Test 1. The stain evaluation was also the same as in Test 1, with "○", "△", or "×" indicating the degree of improvement in the stain rate compared to conventional tobacco paper.

The results are shown in Fig. 2. In the figure, the horizontal axis represents the average fiber length of the pulp used for papermaking, and the vertical axis represents the freeness of the pulp used for papermaking.

It is found that the stain generation rate is reduced in tobacco wrapping paper having a long average fiber length and a low water filterability.

It was found that the conditions for confirming an improvement in the stain generation rate were that the average fiber length of the pulp used in papermaking was 1200 μm or greater and the freeness was 65° SR or less. Furthermore, it was found that the conditions for enhancing the improvement in the stain generation rate were that the average fiber length of the pulp used in papermaking was 1300 μm or greater and the freeness was 57° SR or less.

It should be noted that the upper limit of the average fiber length and the lower limit of the freeness of the pulp used for papermaking are set from the perspective of ensuring the productivity and general physical properties of tobacco paper such as air permeability, and are not set from the perspective of the stain generation rate.

The tobacco paper of the present invention can effectively reduce the generation of stains, even without using a double-layered tobacco paper or applying a surface coating using a large amount of coating agent, as in the prior art. This improves the productivity of the tobacco paper and cigarettes using the same, thereby reducing costs. Furthermore, even when the tobacco paper of the present invention is surface coated, the effect of reducing the generation of stains can be further enhanced, even with a small amount of coating. By using this tobacco paper, even if a larger amount of flavoring agent, such as menthol, is included in the shredded tobacco than usual, the generation of stains can be suppressed.

The combination of average fiber length and freeness for the pulp used in the production of tobacco paper according to the present invention differs significantly from the conventionally used ranges. In the present invention, it is important to use pulp as a raw material having freeness and average fiber length within the specific ranges defined herein, and to produce paper having a specific thickness.

Claims (6)

1. A tobacco rolling paper for rolling tobacco shreds, wherein the tobacco rolling paper is obtained by papermaking of pulp with an average fiber length of 1200-1700 μm and a water content of 30-65°SR, and the average thickness of the rolling paper is 45-100 μm, wherein the pulp is hemp pulp, wood pulp, or a mixture thereof. 2. The tobacco roll paper according to claim 1 is obtained by papermaking of pulp with an average fiber length of 1300-1700 μm and a water permeability of 35-57°SR, and the roll paper has an average thickness of 45-60 μm and an air permeability of 24-110 Coresta units. 3. The tobacco rolling paper according to claim 1 or 2, wherein a film-forming material is added to the surface in contact with the tobacco. 4. A cigarette having tobacco shreds and tobacco rolling paper for rolling the tobacco shreds, wherein the tobacco rolling paper is the tobacco rolling paper according to any one of claims 1 to 3. 5. The cigarette according to claim 4, wherein the tobacco contains flavoring, and the content is 7.5 mg/cigarette or more. 6. The cigarette according to claim 5, wherein the flavoring is menthol.