MXPA98002553A - High opacial wrapping paper - Google Patents

Abstract

The present invention relates to wrapping papers for high opacity cigarette. The wrapping paper made according to the present invention contains a mixture of a white pigment and a black pigment. The white pigment, which may be, for example, calcium carbonate, has an average particle size from about 0.1 microns to about 0.5 microns, and specifically from about 0.2 microns to about 0.4 microns. It has been discovered that this range of particle size, which is equal to one half of the visible wavelength of light, greatly increases the opacity, brightness and whiteness of the paper. Then small amounts of a black pigment, such as coal, are added to further increase the opacity without significantly diminishing the whiteness and brightness of the paper relative to the cigarette paper.

Description

HIGH-OPACITY WRAPPING PAPER Field of the invention The present invention generally relates to high opacity wrapping papers for use in smoking articles and to a method of producing wrapping papers. More particularly, the present invention relates to a wrapping paper containing a mixture of black and white pigments that effectively both disperse and absorb light to increase the opacity of the wrapping paper, while maintaining brightness and the color of the paper within the commercially acceptable ranges.

Background of the Invention Smoldering articles such as cigarettes are conventionally made by wrapping a tobacco column in a white wrapping paper. On the other hand, the smoking article usually includes a filter through which the article is smoked. The filters are attached to the smoking articles using a filter paper which sticks to the white smoking paper. The smoking papers and the filter papers that are used to build the REF: 27057 Steaming articles are typically made from flax or other cellulosic fibers and contain a filler material, such as calcium carbonate.

In addition to being used to hold the cigarette together, also cigarette wrapping papers and filter papers contribute to and control many of the properties and physical characteristics of the cigarette. For example, wrapping paper for cigarettes affects the proportion in which the cigarette is burned, the number of puffs per cigarette and the total tar delivered per puff. Another property of the cigarette that is affected by the wrapper is the appearance and characteristics of the ash that is formed by the cigarette when it is burned. Even cigarette paper can be used to limit the amount of smoke emanating from the lit end of a cigarette when it is burned and to reduce the tendency of a cigarette to ignite adjacent surfaces.

In addition to perform the functions described above, also the cigarette wrapping papers must provide the cigarette with an overall aesthetic appearance. For example, cigarette wrapping papers, which are primarily white, should have as bright a color as possible. Also, the paper must have a very high opacity. Because it has a high opacity, the wrapping paper hides the contents of the cigarette.

In the past, the opacity of the wrapping paper is mainly determined as a function of the amount of filling material included in the paper. In general, the opacity levels increase as the amount of filler material added to the paper increases. Unfortunately, however, increasing fill levels that increase opacity can adversely affect other paper characteristics. For example, increasing levels of fill material can decrease the strength of the paper. The modified filler material levels can each in turn affect the burning properties of the paper. As such, there is increasing pressure within the industry to maintain levels of filler material in cigarette paper within pre-established ranges, severely limiting viable methods to increase paper opacity.

In addition, increasing levels of filler material, the opacity of cigarette paper can also be changed a bit by the change in the amount of fiber refined as a raw material and by the alteration of fiber composition as a raw material. However, also the change of the fiber as raw material or the amount that is refined of this, can adversely interfere with other physical characteristics of the paper. In addition, variable refinement or the selection of a different fiber as a raw material only gives us increased opacity.

Due to the above limitations, commercial cigarette wraps containing calcium carbonate as a filler generally only have an opacity from about 74% to about 76%. In the foregoing, it has been extremely difficult to create a commercially acceptable paper wrapper that has an opacity of 80% or greater.

Therefore, there is a need for a wrapping paper for smoking articles having a high opacity, such as, greater than 80%. Also, there is a need for a method of producing such wraps. There is also a need for a method of increasing the opacity of cigarette wrapping papers without adversely interfering with other physical properties of the paper. There is an additional need for a method to increase the opacity of the cigarette papers without having to increase the levels of filler material.

Brief Description of the Invention The present invention recognizes and refers to the aforementioned disadvantages, and other constructions and methods of the prior art.

In general, the present invention relates to high opacity wrapping papers for use in smoking articles. According to the present invention, the high opacity wrapping papers contain a mixture of a white pigment and a black pigment.

The opacity of paper is a function of both the ease of paper to disperse light and the ease of paper to absorb light. According to the present invention, the white pigment, which may be calcium carbonate within a predetermined size range, is added to the paper to disperse the light. On the other hand, the black pigment, which can be, for example, coal, is added to the paper to absorb light. In general, the black pigment is added in smaller amounts than the amount of white pigment added.

In the above, both the carbon particles and the calcium carbonate have been presented at the same time in the wrapping papers for cigarette. For example, U.S. Pat. No. 3,744,496 by McCarty, et al, refers to a wrap filled with charcoal for smoking articles. The carbon, however, is not added to increase the opacity of the paper, but to reduce the compounds contained within the cigarette smoke. The use of charcoal to retain flavorings, which are released when the cigarette is heated, is also described. In particular, McCarty, et al, describes the addition to paper of about 5% to about 90% by weight of carbon.

When carbon is added to the cigarette papers as described in McCarty, et al., However, carbon significantly decreases the whiteness of the paper and the brightness of the paper to unacceptable levels. Accordingly, the papers filled with more carbon used in the above to reduce the smoke constituents or to maintain the flavorings are used only as internal wraps. In particular, a carbon-filled paper is placed adjacent to the tobacco column and then coated with an outer wrap to improve the aesthetic appearance of the cigarette. As shown in McCarty, et al., The outer wrap is used to conceal the inner lining filled with gray charcoal.

According to the present invention, however, black pigments are included in cigarette wrappers to increase the opacity of cigarette paper, while maintaining the whiteness of the paper and the brightness of the paper to approximately the same levels as the papers. of conventional wrapping. Accordingly, it is an object of the present invention to provide a high opacity paper containing black and white pigments which can be used as an outer wrap for smoking articles.

Another object of the present invention is to provide a wrapping paper for smoking articles having an opacity greater than 80%.

Another object of the present invention is to provide a wrapping paper for smoking articles containing black pigments to increase the opacity, but without decreasing the whiteness and gloss of the paper to an unacceptable level.

Still another object of the present invention is to provide a method for the production of wrapping papers for high opacity cigarette.

Another object of the present invention is to provide cigarette wrapping papers containing a white pigment having a particle size which is approximately equal to a half of the wavelength of visible light in combination with a small amount of a black pigment.

These and other objects of the present invention are achieved by providing a wrapping paper for a smoking article. The wrapping paper includes a paper substrate containing a first filler material and a second filler material. The first filling material comprises a white pigment having an average particle size from about 0.1 microns to about 0.5 microns, and more particularly from about 0.2 microns to about 0.4 microns.

The second filler material comprises a black pigment which is presented within the paper substrate in an amount up to about 2% by weight and particularly from about 0.1% to about 1.0% by weight. According to the present invention, the wrapping paper has an opacity of at least 80% and a brightness of at least 70%.

In one embodiment, the white pigment is calcium carbonate, while the black pigment is carbon, iron oxide, or mixtures thereof. The white pigment may be presented within the paper substrate in an amount of from about 20% to about 40% by weight.

The wrapping paper made in accordance with the present invention can have a basis weight from about 18 gsm to about 60 gsm, a permeability from about 5 Coresta units to about 80 Coresta units and can be coated with an additive for the burn control.

In a preferred embodiment, the wrapping paper has an opacity of at least 90%.

These and other objects of the present invention are also achieved by providing a method for increasing the opacity of a wrapping paper for a smoking article. The method includes the steps of incorporating into a paper substrate a first filler material comprising a white pigment. The white pigment has an average particle size from about 0.1 microns to about 0.5 microns and is added to the substrate in an amount of from about 20% to about 40% by weight.

The method also includes the step of incorporating into the paper substrate a second filler material comprising a black pigment. The black pigment is added in an amount up to about 2% by weight. When the white pigment and the black pigment are combined at the same time as described above, the opacity of the wrapping paper increases to an amount up to at least about 80%, and, in some applications to at least about 90%.

In one embodiment, the white pigment may be calcium carbonate having an average particle size from about 0.2 microns to about 0.4 microns and may be present in the paper in an amount from about 25% to about 35% by weight. The wrapping paper can have a basis weight from about 22 gsm to about 36 gsm and a permeability from about 15 Coresta units to about 55 Coresta units.

Also the present invention relates to smoking articles containing a column of a smoking filler material.

The column of a steaming filler material is surrounded with a high opacity wrapping paper as described above.

Other objects, features and aspects of the present invention are discussed in more detail below.

Brief Description of the Drawings A complete and permitted discovery of the present invention, including the best mode thereof, for one of ordinary skill in the art, is shown more particularly in the remainder of the specification, including reference to the accompanying figures, in which : Figure 1 is a graphic representation of the results obtained in Example 1 below; Figure 2 is a graphic representation of the results obtained in Example 2 below; Figure 3 is a graphic representation of the results obtained in Example 3 below; Detailed description of the preferred modalities It is understood by one of ordinary skill in the art that the present discussion is only a description of the exemplary embodiments, and is not intended to limit the more general aspects of the present invention, the more general aspects are included in the example construction. .

Generally the present invention relates to a high opacity wrapping paper for smoking articles. The wrapping paper contains a white pigment in combination with a black pigment. The white pigment is effective in scattering the light that makes contact with the paper. The black pigment, on the other hand, absorbs light. When used in combination, the opacity of paper greatly increases beyond conventional levels.

Due to the increase in the opacity of the wrapping paper according to the present invention, the overall aesthetic appearance of a steaming article made with the wrapping is greatly increased. The wrapping paper of the present invention may have an opacity, in more examples, greater than at least 80%, which is a significant improvement over conventional cigarette wrapping papers, which typically have an opacity of about 74% up to approximately 76%. In fact, even casings made according to the present invention may have an opacity greater than 90%. For example, up to now, the envelopes have been made having an opacity from about 82% to about 96%. Said high opacity papers, besides having a distinctive and pleasant appearance, are effective when incorporated in a smoking article in the masking of the color and appearance of the tobacco contained within the article.

Of particular advantage, the smoking papers made according to the present invention contain small amounts of a black pigment to increase the opacity of the paper without decreasing the whiteness and brightness of the paper below the acceptable levels, as is not possible in the above using conventional papers. According to the present invention, it has been discovered that a black pigment can be incorporated into a wrapping paper to increase the opacity if it is combined with the white pigment having specially selected optical properties.

In particular, it has been found that white pigments having a particle size within a selected range not only increase the opacity, but also significantly increase the whiteness and brightness of the paper. The increase in brightness and whiteness of the paper above conventional levels make it possible to add black pigments.

Specifically, the white pigment incorporated in the wrapping paper of the present invention should have an average particle size from about 0.1 microns to about 0.5 microns, and specifically from about 0.2 microns to about 0.4 microns. It is believed that the opacity, whiteness and gloss of a wrapping paper incorporating a white pigment within the size range defined above is increased due in part to the fact that the pigment particle size corresponds to approximately one-half the length of visible light wave. Within this range of particle size, it is believed that the white pigment is more effective in scattering light, giving the optical benefits.

In one embodiment, the white pigment incorporated in the wrapping paper of the present invention is calcium carbonate having a particle size from about 0.1 microns to about 0.5 microns. For example, in a preferred embodiment, a calcium carbonate pigment registered under the name ULTRAPAQUE by Speciality Minerals, Inc. of Adams, Massachusetts is used. ULTRAPAQUE is a precipitated calcium carbonate filler material having an average particle size of about 0.3 microns. The calcium carbonate particles have a formology / rhombohedral form and have a surface area of approximately 7.5 m2 / g. ULTRAPAQUE is commercially available as a slurry containing approximately 40% by weight solids or as a dry powder. The slurry or dry powder can be added directly to the cellulosic fibers during the papermaking process. As used herein, the particle size of a composition is measured and determined by a sedimentation process using, for example, a Sedigraf.

In addition to) calcium carbonate, it is believed that other white pigments having a particle size within the range defined above similarly can be used to construct wrapping papers made according to the present invention. Also, it is believed that calcium carbonate can be used alone or in combination with other white pigments.

The black pigment used in combination with the white pigment according to the present invention can be, for example, carbon, such as activated carbon, a black iron oxide, or mixtures thereof. The particle size of the black pigment is generally less critical. For example, in more applications, the particle size of the black pigment may be up to about 10 microns or less. The black pigment must be added to the paper in combination with the white pigment in an amount so as not to diminish the brightness of the paper below the acceptable levels. In general, the brightness of the paper when it contains the black pigment should be at least about 70% as measured by the TAPPI method. Preferably, the paper should have a gloss level from about 70% to about 80%.

Similarly, the black pigment should be added to the paper so that the gloss of the paper does not decrease below conventional levels. For example, the wrapping paper of the present invention should have an L-value of at least about 80% in more applications. The L value is a measure of the whiteness of the paper on the Hunter color scale and is measured using a spectrophotometer, such as the TCS II spectrophotometer. More particularly, the L value of a wrapping paper made according to the present invention can have an L value from about 80% to about 90%.

Thus far, when calcium carbonate is used as the white pigment and either coal or iron oxide is used as the black pigment, the black pigment can be added to the wrapping paper in an amount up to about 2% by weight, and more particularly from about 0.1% to about 1.0% by weight based on the total weight of the paper. According to the present invention, a black pigment can be incorporated into a wrapping paper within the above weight range without decreasing the brightness and whiteness of the paper below the levels described above.

Another significant advantage for the present invention is that the opacity of the wrapping paper can be substantially increased without increasing the levels of total filling material in the paper. As is conventional, casings made according to the present invention can have a level of total filler material, which includes the weight of the black and white pigments, of between about 20% to about 40% by weight, and so particularly between about 25% to about 36% by weight. The filler material can be made completely from black and white pigments or if desired can include other fillers.

In a preferred embodiment, calcium carbonate having a particle size from about 0.1 microns to about 0.5 microns is added to the wrapping paper in an amount of from about 20% to about 40% by weight in combination with a black pigment in a amount up to about 2% by weight. Within these ranges, the opacity of the wrapping paper can be increased without having an effect on the physical properties of the paper, such as the permeability of the paper.

The fiber as the raw material used to make the wrapping papers according to the present invention may include the cellulosic fibers obtained, for example, from flax, softwood and hardwood. To vary the physical properties of the paper, different fiber blends can be used and the amount of refinement of the papers can be varied without affecting the attributes of the present invention.

The permeability of the paper casings made according to the present invention can generally be from about 5 Coresta units to about 80 Coresta units. In more applications, the permeability should be between approximately 15 Coresta units up to approximately 55 Coresta units.

The basis weight of the wrapping papers can be from about 18 gsm to about 60 gs and more particularly from about 22 gsm to about 36 gsm.

Also the wrapping paper can be treated with an additive for the control of burning. Such burn control additives may include, for example, the alkali metal salts, acetates, phosphate salts or mixtures thereof. A particularly preferred burn control additive is a mixture of potassium citrate and sodium citrate. The burn control additive can be added to the paper in an amount from about 0.3% to about 12% by weight, and more particularly from about 0.3% to about 3% by weight.

The black and white pigments of the present invention can be incorporated into the paper wrapper according to various known methods. For example, in one embodiment, the pigments can be combined in a slurry and added to a suspension of cellulosic fibers when the paper is formed.

The present invention can be better understood with reference to the following examples.

EXAMPLE NO.

To demonstrate the present invention, several hand sheets are made by incorporating a black pigment and a white pigment into the paper. In a set of hand sheets, the white pigment incorporated in the paper is an ALBACAR 5970 calcium carbonate filler material, a conventionally used filler material having an average particle size of about 1.9 microns. The ALBACAR 5970 filler material, which is obtained from Specialty Minerals, Inc. of Adamns, Massachusetts, is incorporated into the paper in an amount of 28% by weight. The paper in this first set has a basis weight of 28 gsm.

In a second set of hand sheets, instead of the ALBACAR 5970 filler material, the ULTRAPAQUE calcium carbonate particles, having an average particle size of about 0.3 microns, are added to the paper according to the present invention. The ULTRAPAQUE filling material is added to the paper in an amount of 28% by weight. The base weight of the paper is 28 gsm.

Also a third set of hand sheets are made containing ULTRAPAQUE particles according to the present invention. In this third set, however, the ULTRAPAQUE is added in an amount of 31% by weight. The manual sheets have a base weight of 31 gsm.

To each of the three sets of hand sheets described above, activated carbon is added in increasing amounts up to 1% by weight. Activated carbon is obtained from the Calgon Corporation of Pittsburgh, Pennsylvania and registered under the trademark KCG. Then the opacity of the manual sheets is measured using an opacity measuring instrument. The results are illustrated in figure 1.

Figure 1 shows how the opacity increases as it increases the level of activated carbon. As shown, the manual sheets containing the white pigment having an average size of 0.3 microns according to the present invention, have an initial and final opacity much higher than the manual sheets made with the ALBACAR 5970 filler material. , the manual sheets containing the ULTRAPAQUE pigment have an opacity greater than 90% when the carbon is added in an amount of 1% by weight.

EXAMPLE NO. 2 Also the same hand sheets made in Example No. 1 are tested by the value L, which is a measure of the whiteness of the paper on the Hunter color scale. The results of the test are illustrated in Figure 2.

Figure 2 illustrates how the L value or the whiteness of the paper decreases since increasing amounts of a black pigment are added to the paper.

Also as shown, however, the manual sheets made with a ULTRAPAQUE filling material have a much higher initial whiteness than the manual sheets made with ALBACAR 5970. In reality, the pigment and 1% by weight of carbon have a whiteness value comparable with the initial whiteness value of the manual sheets of less carbon containing ALBACAR 5970 pigment.

EXAMPLE NO.

Also the hand sheets described in Example 1 are tested for gloss using a gloss measurement instrument. The results obtained are illustrated in Figure 3.

As shown in Figure 3, the initial brightness of the hand sheets made according to the present invention containing a ULTRAPAQUE filling material is much greater than the brightness of the less carbon hand sheets made using ALBACAR 5970.

As the carbon is added to the manual sheets, the brightness of the paper decreases. However, since the initial brightness of the ULTRAPAQUE that contains the leaves is much greater than the initial brightness of the manual leaves that contain ALBACAR 5970, the carbon can be added to the leaves with ULTRAPAQUE without causing the brightness of the leaves to diminish significantly below the initial brightness of the leaves with ALBACAR 5970 that does not contain carbon.

These and other modifications and variations for the present invention can be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which are more particularly shown in the appended claims. It should further be understood that aspects of the various modalities may be exchanged in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the aforementioned description is only by way of example, and is not intended to limit the invention, so it is further described in the appended claims.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objectives to which it relates.

Having described the invention as above, the content of the following is claimed as property.

Claims (27)

1 . A wrapping paper for a smoking or smoking article, characterized in that it comprises: a paper substrate containing a first filling material and a second filling material, the first filling material comprising a white pigment having an average particle size from about 0.1 microns to about 0.5 microns, the second filling material comprising a Black pigment which is presented within the paper substrate in an amount up to about 2% by weight, the wrapping paper has an opacity of at least 80% and a brightness of at least 70%.

2. A wrapping paper according to claim 1, characterized in that the white pigment comprises a calcium carbonate.

3. A wrapping paper according to claim 1, characterized in that the black pigment comprises a material selected from the group consisting of carbon, iron oxide, and mixtures thereof.

4. A wrapping paper according to claim 1, characterized in that the white pigment is presented within the paper substrate in an amount from about 20% to about 40% by weight.

5. A wrapping paper according to claim 1, characterized in that the white pigment has an average particle size from about 0.2 microns to about 0.4 microns.

6. A wrapping paper according to claim 1, characterized in that the paper substrate has a basis weight from about 18 gsm to about 60 gsm and has a permeability from about 5 Coresta units to about 80 Coresta units.

7. A wrapping paper according to claim 6, characterized in that it also comprises an additive for the control of burning coated on the paper substrate, the additive for the control of burning is a material selected from the group consisting of alkali metal salts, acetates, phosphate salts, and mixtures thereof.

8. A wrapping paper according to claim 1, characterized in that the wrapping paper has an opacity of at least 90%.

9. A wrapping paper according to claim 1, characterized in that the black pigment is presented within the paper substrate in an amount from about 0.1% to about 1.0% by weight.

10. A wrapping paper for a steaming or fuming article, characterized in that it comprises: a paper substrate containing a first filling material and a second filling material, the first filling material comprising a calcium carbonate which has a particle size medium from about 0.1 microns to about 0.5 microns, the calcium carbonate is presented within the paper substrate in an amount of from about 20% to about 40% by weight, the second filler comprising a black pigment that occurs within the substrate of paper in an amount up to about 2% by weight.

11. A wrapping paper according to claim 10, characterized in that the wrapping paper has an opacity of at least 80% and a brightness of at least 70%.

12. A wrapping paper according to claim 11, characterized in that the wrapping paper has an opacity of at least 90%.

13. A wrapping paper according to claim 11, characterized in that the wrapping paper has an L value of at least about 80%.

14. A paper according to claim 1, characterized in that the black pigment comprises a material selected from the group consisting of carbon, iron oxide, and mixtures thereof, the black pigment is presented within the paper substrate in an amount from about 0.1% to about 1.0% by weight.

15. A wrapping paper according to claim 14, characterized in that the calcium carbonate has an average particle size from about 0.2 microns to about 0.4 microns.

16. A wrapping paper according to claim 10, characterized in that the paper substrate has a basis weight from about 22 gsm to about 36 gsm, has a permeability from about 15 Coresta units to about 55 Coresta units, and has a content of material of total fill from about 25% to about 36% by weight.

17. A method for increasing the opacity of a wrapping paper for a smoking article, characterized in that it catches the steps: incorporation into a paper substrate of a first filling material comprising a white pigment, the white pigment having an average particle size from about 0.1 microns to about 0.5 microns, the white pigment is added to the paper substrate in an amount from about 20% up to about 40% by weight. incorporation into a paper substrate of a second filler material comprising a black pigment, the black pigment being added to the paper substrate in an amount up to about 2% by weight; Y wherein the white pigment and the black pigment are added to the wrapping paper in an amount sufficient to increase the opacity of the wrapping paper to at least about 80%.

18. A method according to claim 17, characterized in that the wrapping paper has a brightness of at least about 70% and an L value of at least about 80%.

19. A method according to claim 17, characterized in that the white pigment comprises a calcium carbonate.

20. A method according to claim 19, characterized in that the white pigment is presented within the paper substrate in an amount from about 25% to about 35% by weight and has an average particle size from about 0.2 microns to about 0.4 microns.

21. A method according to claim 20, characterized in that the black pigment comprises a material selected from the group consisting of carbon, iron oxide, and mixtures thereof.

22. A method according to claim 21, characterized in that the wrapping paper has a basis weight from about 22 gsm to about 36 gsm and a permeability from about 15 Coresta units to about 55 Coresta units.

23. A method according to claim 22, characterized in that the wrapping paper has an opacity of at least about 90%.

24. A smoking or smoking article, characterized in that it comprises: a column of a steaming filler material; Y a wrapping paper surrounding the column of the steaming filler material, the wrapping paper comprises a paper substrate containing calcium carbonate having an average particle size from about 0.2 microns to about 0.4 microns, also the paper substrate contains a white pigment, the wrapping paper has a basis weight from about 22 gsm to about 36 gsm, a permeability from about 15 Coresta units to about 55 Coresta units, a total filler content from about 25% to about 36% in weight, and an opacity of at least approximately 80%.

25. A smoking article according to claim 24, characterized in that the black pigment comprises a carbon, the carbon is presented within the paper substrate in an amount up to about 2% by weight.

26. A smoking article according to claim 24, characterized in that the wrapping paper has a brightness of at least about 70% and an L value of at least about 80%.

27. A smoking article according to claim 24, characterized in that the wrapping paper has an opacity of at least about 90%.