Wrapper Paper for Smoking Articles, with Improved Ash Formation

Abstract

The invention relates to a wrapper paper for smoking articles, comprising cellulose fibres loaded with calcium carbonate particles, wherein the mass of the cellulose fibres loaded with calcium carbonate particles is at least 1% of the mass of the wrapper paper, and the calcium carbonate particles in the cellulose fibres loaded with calcium carbonate particles make up at least 5% and no more than 80% of the mass of the cellulose fibres loaded with calcium carbonate particles.

Claims

1. Wrapper paper for smoking articles, which comprises pulp fibers loaded with calcium carbonate particles, wherein the mass of the pulp fibers loaded with calcium carbonate particles is at least 1% of the mass of the wrapper paper and the calcium carbonate particles in the pulp fibers loaded with calcium carbonate particles make up at least 20% and at most 80% of the mass of the pulp fibers loaded with calcium carbonate particles, and the wrapper paper has an air permeability in accordance with ISO 2965:2019 of at least 50 cm.sup.3/(cm.sup.2.Math.min.Math.kPa) and at most 300 cm.sup.3/(cm.sup.2.Math.min.Math.kPa).

2. Wrapper paper according to claim 1 which, in addition to the pulp fibers loaded with calcium carbonate particles, also contains pulp fibers which are not loaded with calcium carbonate particles and their proportion is at least 10% and at most 80%, each with respect to the mass of the wrapper paper.

3. Wrapper paper according to claim 1, wherein the pulp fibers loaded with calcium carbonate particles and, if present, also the pulp fibers not loaded with calcium carbonate particles, are at least partially sourced from spruce, pine or fir, f eucalyptus, birch or beech, or from hemp, flax, sisal, aback or cotton.

4. (canceled)

5. Wrapper paper according to claim 1, wherein the pulp fibers loaded with calcium carbonate particles are at least partially located in the bulk of the wrapper paper, wherein the proportion of pulp fibers loaded with calcium carbonate particles is at least 5% and at most 80%, each with respect to the mass of the wrapper paper.

6. Wrapper paper according to claim 1, which has a coating and wherein the pulp fibers loaded with calcium carbonate particles are at least partially located in the coating, wherein their proportion, in the case in which the pulp fibers loaded with calcium carbonate particles are exclusively located in the coating, is at least 1% and at most 30%, each with respect to the mass of the wrapper paper.

7. Wrapper paper according to claim 1, wherein the calcium carbonate particles of the pulp fibers loaded with calcium carbonate particles are formed by precipitated calcium carbonate particles with a rhombohedral structure.

8. Wrapper paper according to claim 1, wherein the mass of the calcium carbonate particles with respect to the mass of the pulp fibers loaded with calcium carbonate particles is at least 20% and at most 60%.

9. Wrapper paper according to claim 1, which further contains free filler materials that are not bonded to the pulp fibers, wherein the proportion of free filler materials is at least 1% and at most 40%, each with respect to the mass of the wrapper paper.

10. Wrapper paper according to claim 9, wherein the free filler materials are formed by calcium carbonate, magnesium carbonate, magnesium oxide, magnesium hydroxide, aluminum hydroxide, titanium dioxide, talcum, kaolin, calcinated kaolin and mixtures thereof.

11.-13. (canceled)

14. Wrapper paper according to claim 1, wherein at least 95% of its surface has a coating which contains pulp fibers loaded with calcium carbonate particles.

15. Wrapper paper according to claim 14, wherein the coating further comprises a binder that is suitable for binding the free calcium carbonate particles or the pulp fibers loaded with calcium carbonate particles to the wrapper paper.

16. Wrapper paper according to claim 14, wherein the coating comprises further components selected from the group consisting of burn additives, colorants, flavors, humectants, glycerol or propylene glycol, or substances for adjusting the viscosity.

17. Wrapper paper according to claim 14, wherein the coating is located on that side of the wrapper paper that faces the outside of the smoking article to be manufactured therefrom.

18. Wrapper paper according to claim 14, wherein the mass per unit area of the coating is at least 0.5 g/m.sup.2 and at most 10 g/m.sup.2.

19. (canceled)

20. Wrapper paper according to claim 19, which additionally contains pulp fibers loaded with calcium carbonate particles in the bulk, wherein the mass of the pulp fibers loaded with calcium carbonate particles in the wrapper paper without the coating is at least 1% and at most 60% of the mass of the wrapper paper and the calcium carbonate particles in the pulp fibers loaded with calcium carbonate particles make up at least 10% and at most 60% of the mass of the pulp fibers loaded with calcium carbonate particles.

21. (canceled)

22. Wrapper paper according to claim 1, with a basis weight of at least 20 g/m.sup.2 and at most 120 g/m.sup.2, wherein a coating, if present, counts towards the basis weight of the wrapper paper.

23. (canceled)

24. Wrapper paper according to claim 1, with a tensile strength of at least 10 N/15 mm.

25. Wrapper paper according to claim 1, with a tensile strength of at most 100 N/15 mm.

26.-27. (canceled)

28. Wrapper paper according to claim 1, with a brightness in accordance with ISO 2470-1:2016 of at least 90%.

29. Wrapper paper according to claim 1, with an opacity in accordance with ISO 2471:2008 of at least at least 80%.

30-31. (canceled)

32. Laminate comprising a wrapper paper according to claim 1 and a further material the thermal conductivity of which exceeds the thermal conductivity of the wrapper paper by a factor of at least two.

33. Smoking article comprising an aerosol-forming material and a wrapper paper according to claim 1.

34. Smoking article according to claim 33, wherein the aerosol-forming material comprises tobacco, wherein the smoking article is a cigarette and the wrapper paper is a cigarette paper.

35. Smoking article according to claim 33 in which, during its intended use, the aerosol-forming material is only heated but not burnt.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0057] FIG. 1 shows, by way of example, an electron micrograph of pulp fibers loaded with coarse calcium carbonate particles, wherein the calcium carbonate particles make up about 20% of the mass of the pulp fibers loaded with calcium carbonate particles.

[0058] FIG. 2 shows, by way of example, an electron micrograph of pulp fibers loaded with fine calcium carbonate particles, wherein the calcium carbonate particles make up about 20% of the mass of the pulp fibers loaded with calcium carbonate particles.

[0059] FIG. 3 shows the ash appearance of three filter cigarettes made from a wrapper paper not according to the invention.

[0060] FIG. 4 shows the ash appearance of three filter cigarettes made from a wrapper paper according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0061] Some preferred embodiments of wrapper papers according to the invention are described below and are compared with a wrapper paper not according to the invention.

[0062] The wrapper paper not according to the invention, which serves as a reference, has a basis weight of 32.6 g/m.sup.2 and was manufactured from 28% pulp fibers from coniferous wood and 42% pulp fibers from deciduous wood as well as 30% free calcium carbonate particles, wherein the percentages are with respect to the mass of the wrapper paper. Further properties of the wrapper paper are shown in Table 1 in the row “REF”.

[0063] In total, 14 wrapper papers according to the invention, designated by A to K and X to Z, were manufactured, wherein the composition of the wrapper papers is shown in Table 1. In Table 1, “SW” in % indicates the proportion of pulp fibers from coniferous woods, “HW” in % indicates the proportion of pulp fibers from deciduous woods, “CF” in % indicates the proportion of pulp fibers loaded with calcium carbonate particles and “FI” in % indicates the proportion of free filler materials. The percentages are with respect to the mass of the wrapper paper.

[0064] The pulp fibers from coniferous and deciduous wood types are standard products available on the market. The pulp fibers loaded with calcium carbonate particles were obtained from the company Schaefer Kalk. The entire free filler was formed by precipitated calcium carbonate particles.

[0065] Furthermore, in Table 1 under “CCP”, the mass of the calcium carbonate particles in the pulp fibers loaded with calcium carbonate particles is given as a % with respect to the mass of pulp fibers loaded with calcium carbonate particles. In addition, the size of these particles is indicated as “fine” or “coarse”. In this context, FIG. 1 shows an electron micrograph of pulp fibers loaded with coarse calcium carbonate particles and FIG. 2 shows an electron micrograph of pulp fibers loaded with fine calcium carbonate particles, in the way both were used for the manufacture of some wrapper papers according to the invention. The proportion by weight of the calcium carbonate particles in the pulp fibers loaded with calcium carbonate particles from FIGS. 1 and 2 was about 17.3%. The pulp fibers were formed by pulp fibers from eucalyptus.

[0066] The wrapper paper X was identical to the wrapper paper REF and the wrapper papers Y and Z were identical to wrapper paper G. The entire surface of the wrapper paper Y was coated with a composition of 89% water, 5.5% mechanically fragmented and chemically cross-linked starch and 5.5% free calcium carbonate particles, wherein the percentages are with respect to the mass of the composition. The entire surface of the wrapper papers X and Z were coated with a composition of 95.5% water, 1% mechanically fragmented and chemically cross-linked starch and 3.5% pulp fibers loaded with calcium carbonate particles, wherein the percentages are with respect to the mass of the composition. After application and drying of the composition, a mass of about 2 g/m.sup.2 remained on the wrapper papers.

[0067] The mechanically fragmented, chemically cross-linked starch can, for example, be obtained from the company Emsland-Stärke GmbH.

TABLE-US-00001 TABLE 1 CCP CF SW HW FI Paper % Size % % % % REF 0 28 42 30 A 25.3 fine 42 28 0 30 B 25.3 fine 36 24 0 40 C 17.3 coarse 21 28 21 30 D 17.3 coarse 18 24 18 40 E 17.3 coarse 42 28 0 30 F 17.3 coarse 36 24 0 40 G 25.5 coarse 42 28 0 30 H 25.5 coarse 36 24 0 40 I 33.7 coarse 21 28 21 30 J 33.7 coarse 42 28 0 30 K 33.7 coarse 36 24 0 40 X 0 28 42 30 Y 25.5 coarse 42 28 0 30 Z 25.5 coarse 42 28 0 30

[0068] The properties of the wrapper paper REF not according to the invention and the wrapper papers A to K and X to Z according to the invention were determined and are shown in Table 2, wherein “BW” is the basis weight, “EL” is the elongation at break and “AP” is the air permeability.

TABLE-US-00002 TABLE 2 Tensile Thick- Strength Bright- Opa- AP BW ness N/15 EL TEA ness city cm.sup.3/(cm.sup.2 .Math. Paper g/m.sup.2 μm mm % J/m.sup.2 % % min .Math. kPa) REF 32.6 63 12.3 1.6 9.5 93 82 47 A 29.6 64 7.2 1.1 3.9 92 78 81 B 34.3 65 8.3 1.0 3.9 93 81 71 C 29.9 63 10.8 1.4 7.5 93 78 105 D 30.4 64 6.3 1.1 3.4 93 83 135 E 30.5 66 9.4 1.5 6.6 93 81 102 F 31.1 66 8.1 1.3 4.8 93 83 100 G 33.2 69 11.2 1.6 8.4 93 82 105 H 31.1 66 8.7 1.4 5.7 93 82 123 I 30.0 65 8.9 1.4 5.7 93 80 132 J 32.8 68 11.5 1.5 8.1 93 81 90 K 30.8 64 8.5 1.3 5.4 93 82 130 X 34.6 67 16.9 1.4 10.9 92 83 42 Y 35.3 70 16.3 1.4 10.7 93 84 83 Z 35.0 71 16.8 1.3 11.0 93 85 80

[0069] Smoking articles in the form of filter cigarettes with a diameter of about 7.8 mm and a length of 83 mm were manufactured from the wrapper paper REF not according to the invention and the wrapper papers A to K and X to Z according to the invention. The tobacco used was an American Blend and the wrapper papers each wrapped the tobacco. The ash appearance of these smoking articles was assessed by means of an image analysis method. In this regard three pieces from each cigarette were lit in a vertical position and left until complete combustion of the tobacco. Next, a digital image of each cigarette was taken under constant lighting conditions in front of a neutral background. Then image analysis software determined the proportion of non-white areas in the region of the combusted tobacco rod. This proportion of non-white areas with respect to the total area of the combusted tobacco rod was expressed as a percentage and reported as “Ash Index”, wherein a mean value was determined from the images of three cigarettes. The higher the percentage, the more non-white areas are contained in the combusted tobacco rod and the worse the consumer will judge the ash appearance.

[0070] The Ash Index determined in this manner is shown in Table 3.

TABLE-US-00003 TABLE 3 Ash Index Paper % REF 11.1 A 9.5 B 8.6 C 7.6 D 4.8 E 7.7 F 5.8 G 6.5 H 8.2 I 7.0 J 7.5 K 5.1 X 8.5 Y 4.3 Z 4.5

[0071] FIG. 3 shows the ash appearance of three filter cigarettes that were manufactured from the wrapper paper REF not according to the invention. FIG. 4 shows the ash appearance of three filter cigarettes that were manufactured from wrapper paper K according to the invention. Even without quantifying the ash appearance by image analysis, the difference is already clearly visible.

[0072] The purpose of wrapper papers A to K according to the invention was to achieve properties as similar as possible compared with the wrapper paper REF not according to the invention, to be able to clearly show the positive effect of the pulp fibers loaded with calcium carbonate particles. The examples are thus not to be understood as limiting the invention and the skilled person will be able to manufacture wrapper papers according to the invention with, for example, a different composition, different basis weight, different thickness, different air permeability or other mechanical or optical properties within the claimed range.

[0073] From Table 3 it can be seen that the Ash Index of cigarettes with wrapper papers A to K is always lower than that of cigarette with wrapper paper REF not according to the invention. This means that wrapper papers A to K lead to a better ash appearance.

[0074] From Table 2 it can be seen that, as was intended by the manufacture of the wrapper papers, wrapper papers A to K according to the invention are very similar to wrapper paper REF not according to the invention with respect to basis weight, thickness, elongation at break, brightness and opacity. The tensile strength and hence also the tensile energy absorption of wrapper papers A to K is slightly lower than for wrapper paper REF not according to the invention. This is caused by the pulp fibers loaded with calcium carbonate particles, because the calcium carbonate particles on the pulp fibers prevent the formation of hydrogen bonds between the pulp fibers and therefore reduce the tensile strength of the wrapper paper.

[0075] It is important that the air permeability of wrapper papers A to K is higher than that of the wrapper paper not according to the invention. Despite this higher air permeability, the cigarettes manufactured from wrapper papers A to K have a better ash appearance than the cigarettes produced from wrapper paper REF. This shows that at high air permeability, the use of pulp fibers loaded with calcium carbonate particles offers a particular advantage.

[0076] If needed, the skilled person can, of course, reduce the air permeability of wrapper papers A to K, for example by more intensive refining of the pulp fibers, and therefore obtain the same value as for wrapper paper REF. It is then to be expected that the Ash Index will decrease further, and the ash appearance will improve even further.

[0077] A comparison between wrapper paper I (Ash Index 7.9), which in total contains about 36% calcium carbonate particles, free and bound to the pulp fibers, and the wrapper paper REF not according to the invention (Ash Index 11.1), which contains 40% exclusively free calcium carbonate particles, shows that the ash appearance can be improved despite the lower total content of calcium carbonate particles.

[0078] The coated wrapper papers X, Y and Z all exhibit an improvement in the ash appearance. Papers X to Z also all have a higher tensile strength than wrapper paper REF not according to the invention and than the uncoated wrapper papers A to K according to the invention, which is a further advantage of these embodiments.

[0079] In total, it can be seen that with the wrapper papers according to the invention a substantial improvement in the ash appearance can be achieved without having a negative influence on other properties of the wrapper paper and without substantially increasing the mass of the wrapper paper or adding uncommon components to the wrapper paper.