PREPARATION METHOD OF TOBACCO SHEETS WITH A REDUCED QUANTITY OF WOOD PULP FIBERS

Abstract

The present invention provides a preparation method of tobacco sheets with a reduced quantity of wood pulp fibers, and belongs to the technical field of reconstituted tobacco. The method includes the steps of: cooking tobacco stem materials by alkaline process, and filtering and washing the cooked tobacco stem materials to obtain tobacco stem fibers; generating mixed pulp by mixing wood pulp fibers, tobacco pulp, filling materials, water and the tobacco stem fibers together as per certain proportions, and subjecting the mixed pulp to a papermaking process in a paper machine to obtain tobacco sheets. By means of adding tobacco stem fibers, the present invention effectively reduces the quantity of wood pulp fibers, ensures the continuous operation of the paper machine, and effectively improves the bulk and tensile index of prepared tobacco sheets. Furthermore, the present invention reduces the quantity of wood pulp fibers, improves the flavor of tobacco, and effectively relieves the negative effect of excessive wood pulp fibers on the flavor of tobacco.

Description

TECHNICAL FIELD

The present invention relates to the field of reconstituted tobacco, in particular to a preparation method of tobacco sheets with a reduced quantity of wood pulp fibers.

BACKGROUND

The production of tobacco sheets is most commonly done by the papermaking process. In order to keep the paper machine in continuous operation during production, some wood pulp fibers for making paper generally need to be added in the process of producing tobacco sheets. This addition enables tobacco pulp to be molded smoothly in the papermaking system, ensuring continuous operation of the paper machine. Furthermore, the added wood pulp fibers can serve as the skeleton of tobacco sheets to help improve the strength of tobacco sheets.

However, adding wood pulp fibers has certain negative effects on the flavor of tobacco sheets. The addition of wood pulp fibers produces a wood smell in smoking tobacco sheets, thus reducing the original scent of tobacco.

SUMMARY

In order to solve the aforementioned technical problem, the prevent invention provides a preparation method of tobacco sheets with a reduced quantity of wood pulp fibers. The preparation method disclosed by the present invention effectively reduces the quantity of wood pulp fibers and still allows tobacco pulp to be molded smoothly in the papermaking system. In addition, the resulting tobacco sheets have high or increased strength.

The present invention provides a preparation method of tobacco sheets with a reduced quantity of wood pulp fibers, including the following steps:

(1) cooking tobacco stem materials by alkaline process, and filtering and washing the cooked tobacco stem materials to obtain tobacco stem fibers; and

(2) generating mixed pulp by mixing wood pulp fibers, tobacco pulp, filling materials, water and the tobacco stem fibers obtained in step (1) together as per certain proportions, and subjecting the mixed pulp to a papermaking process in a paper machine to obtain tobacco sheets.

Preferably, the length of the tobacco stem fibers in step (1) is preferably about 0.1-0.5 mm and the diameter is about 0.5-2 p.m.

Preferably, in step (1), strong alkali, the tobacco stem materials and water are mixed and then cooked, the mass concentration of the strong alkali is 15-50%, and the mass ratio of the tobacco stem materials to the strong alkali is (4.5-5.5):1.

Preferably, in step (1), the temperature for cooking is 150-180° C. and the time for cooking is 1-4 h.

Preferably, in step (2), the mass content of the tobacco stem fibers in the mixed pulp is 0.1-3%.

Preferably, in step (2), the mass content of the wood pulp fibers in the mixed pulp is 14-22%.

Preferably, in step (2), the filling materials comprise calcium carbonate.

Preferably, in step (2), the mass content of the filling materials in the mixed pulp is 8-20%.

Preferably, in step (2), the tobacco pulp includes tobacco stem pulp and tobacco leaf pulp, and the mass concentration of the tobacco pulp is 5-15%.

Preferably, in step (2), the mass concentration of the mixed pulp in the tobacco sheets is 0.1-1.0%.

The preparation method of the tobacco sheets with a reduced quantity of wood pulp fibers, provided by the invention includes the steps of: cooking tobacco stem materials by alkaline process, and filtering and washing the cooked tobacco stem materials to obtain tobacco stem fibers; generating mixed pulp by mixing wood pulp fibers, tobacco pulp, filling materials, water and the tobacco stem fibers together as per certain proportions, and subjecting the mixed pulp to a papermaking process in a paper machine to obtain tobacco sheets. By means of adding tobacco stem fibers, the present invention effectively reduces the quantity of wood pulp fibers, ensures the continuous operation of the paper machine, and effectively improves the bulk and tensile index of prepared tobacco sheets. Furthermore, by reducing the quantity of wood pulp fibers, the present invention improves the flavor of tobacco effectively relieving the negative effect of excessive wood pulp fibers on the flavor of tobacco.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a scanning electron microscope picture of the tobacco stem fibers after being cooked in a strong alkali solution in preferred embodiment 1 of the present invention.

DETAILED DESCRIPTION

The present invention provides a preparation method of tobacco sheets with a reduced quantity of wood pulp fibers, which includes the following steps:

(1) cooking tobacco stem materials by alkaline process, and filtering and washing the cooked tobacco stem materials to obtain tobacco stem fibers; and

(2) generating mixed pulp by mixing wood pulp fibers, tobacco pulp, filling materials, water and the tobacco stem fibers obtained in step (1) together as per certain proportions, and subjecting the mixed pulp to a papermaking process in a paper machine to obtain tobacco sheets.

In the present invention, an alkaline process is adopted to cook tobacco stem materials to obtain cooked aqueous pulp.

In the present invention, an aqueous solution of strong alkali, the tobacco stem materials and water are mixed and then cooked. The mass concentration of the aqueous solution of strong alkali is preferably 15-50%, more preferably 20-40%, and most preferably 25-35%. The aqueous solution of strong alkali preferably includes an aqueous sodium or potassium hydroxide solution.

In the present invention, the mass ratio of the tobacco stem materials to the aqueous solution of strong alkali is preferably (4.5-5.5):1 and more preferably 5:1.

In the present invention, the solid-liquid mass ratio in the mixture of the aqueous solution of strong alkali, tobacco stem materials and water is preferably 1:(4.5-5.5) and more preferably 1:5.

In the present invention, the temperature for the cooking is preferably 150-180° C. and more preferably 160-170° C.; the time is preferably 1-4 h and more preferably 2-3 h.

In cooking by alkaline process in the present invention, substances in tobacco stems such as lignin and pectin can dissolve in the strong alkali solution. Tobacco stem fibers in tobacco stems are insoluble in the strong alkali solution. Follow-up filtration helps extract tobacco stem fibers.

Cooked aqueous pulp is obtained after cooking. In the present invention, the cooked aqueous pulp is filtered to obtain tobacco stem fibers.

The present invention imposes no specific limitation on the implementation of filtration in the present invention, and any mode of filtration well known by those skilled in the art may be adopted.

After filtration, the cooked fibers are preferably washed with water. The present invention imposes no specific limitation on the implementation of washing in the present invention, and any washing mode well known by those skilled in the art may be adopted.

In the present invention, the length of the tobacco stem fibers obtained by the above modes is preferably 0.1-0.5 mm and more preferably 0.2-0.4 mm; the diameter is preferably 0.5-2 μm and more preferably 1.0-1.5 μm; the Kappa number of the tobacco stem fibers is preferably 3-10, more preferably 4-9 and most preferably 5-8. In the present invention, the tobacco stem fibers, having been cooked in the strong alkaline solution, have ideal length, diameter and Kappa number, and thus, the strength of tobacco sheets is improved and the smooth operation of the paper machine is ensured.

In the present invention, after the tobacco stem fibers are obtained, mixed pulp is generated by mixing wood pulp fibers, tobacco pulp, filling materials, water and the tobacco stem fibers together as per certain proportions, and tobacco sheets are obtained by subjecting the mixed pulp to a papermaking process in a paper machine.

In the present invention, the mass content of the wood pulp fibers in the mixed pulp is preferably 14-22%, more preferably 15-19% and most preferably 16-18%.

In the present invention, the mass content of the tobacco stem fibers in the mixed pulp is preferably 0.1-3%, more preferably 0.5-2.5% and most preferably 1.0-2.0%.

By adding tobacco stem fibers during the preparation of tobacco sheets, the present invention effectively reduces the quantity of wood pulp fibers and effectively improves the strength of tobacco sheets.

In the present invention, the tobacco pulp preferably includes tobacco stem pulp and tobacco leaf pulp; the mass concentration of the tobacco pulp is preferably 5-15% and more preferably 8-12%. In the present invention, the solvent in the tobacco pulp is preferably water.

In the present invention, the filling materials preferably include calcium carbonate. The mass content of the filling materials in the mixed pulp is preferably 8-20%, more preferably 10-15% and most preferably 12-14%.

In the present invention, the mass concentration of the mixed pulp is preferably 0.1-1.0% and more preferably 0.5%.

The obtained mixed pulp is subjected to a papermaking process in the paper machine in the present invention to obtain tobacco sheets.

In the present invention, the retention agent added during the paper making process in the paper machine preferably includes cationic guar gum or chitosan. The mass ratio of the retention agent to the mixed pulp is preferably (0.05-0.3%):1, more preferably (0.1-0.25%):1 and most preferably (0.15-0.2%):1.

The present invention imposes no specific limitation on the implementation of the papermaking process in the paper machine in the present invention, and any papermaking mode in the paper machine well known by those skilled in the art may be adopted.

The technical scheme in the present invention will now be described clearly and fully detailed with reference to the following preferred embodiments in the present invention.

Preferred Embodiment 1

10 kg of tobacco stem materials and 2 kg of aqueous sodium hydroxide solution (50% mass concentration) are added with water to make the solid-liquid mass ratio in the reaction system be 1:5, wherein the cooking conditions are 170° C. for 3 h. After cooking, the cooked aqueous pulp is filtered and the filter cakes are washed with water to obtain tobacco stem fibers.

The mixed pulp is prepared as per certain mass proportions: 100 parts of tobacco pulp (10% mass concentration), 20 parts of wood pulp fibers, 0.5 parts of tobacco stem fibers, and 15 parts calcium carbonate; and a 0.5% mass concentration of the mixed pulp is obtained by adding water. Tobacco sheets are obtained by papermaking process in the paper machine. Cationic guar gum is added as a retention agent during the papermaking process.

FIG. 1 shows a scanning electron microscope picture of the tobacco stem fibers after being cooked in an aqueous sodium hydroxide solution.

Preferred Embodiment 2

Testing is conducted according to the method in preferred embodiment 1, except that there are 1.0 parts of tobacco stem fibers utilized in the mixed pulp preparation, not 0.5 parts as specified in preferred embodiment 1.

Preferred Embodiment 3

Testing is conducted according to the method in preferred embodiment 1, except that there are 2.0 parts of tobacco stem fibers utilized in the mixed pulp preparation, not 0.5 parts as specified in preferred embodiment 1.

Preferred Embodiment 4

Testing is conducted according to the method in preferred embodiment 1, except that there are 4.0 parts of tobacco stem fibers utilized in the mixed pulp preparation, not 0.5 parts as specified in preferred embodiment 1.

REFERENCE EXAMPLE 1

Testing is conducted according to the method in preferred embodiment 1, except that 0 parts of tobacco stem fibers and 25 parts of wood pulp fibers are utilized in the mixed pulp preparation, not 0.5 parts and 20 parts, as specified in preferred embodiment 1, respectively.

REFERENCE EXAMPLE 2

Testing is conducted according to the method in preferred embodiment 1, except that 0 parts of tobacco stem fibers are utilized in the mixed pulp preparation, not 0.5 parts as specified in preferred embodiment 1, respectively.

The strength of the tobacco sheets prepared respectively by embodiments 1-4 and reference examples 1-2 is tested, with the test results shown in Table 1:

TABLE 1
Effects of quantity of tobacco stem fibers on physical properties of tobacco sheets
	Reference	Reference	Embodiment	Embodiment	Embodiment	Embodiment
	example 1	example 2	1	2	3	4
Wood pulp fibers	25 parts	20 parts
Tobacco stem fibers	0	0	0.5 part	1.0 part	2.0 parts	4.0 parts
Bulk (cm3/g)	2.04	2.06	2.10	2.11	2.07	2.03
Tensile index (N · m/g)	11.18	10.20	10.32	11.77	12.80	13.89

As can be seen from the test results in Table 1, the present invention effectively reduces the quantity of wood pulp fibers and improves the bulk and tensile index (after 1.0 part) of the tobacco sheets by adding tobacco stem fibers.

Preferred Embodiment 5

Testing is conducted according to the method in preferred embodiment 1, except that 16 parts of wood pulp fibers, and 0.5 parts, 1.0 parts, and 2.0 parts of the tobacco stem fibers are utilized in the mixed pulp preparation, respectively. The physical properties of the tobacco sheets obtained by adding different amounts of tobacco stem fibers are tested respectively, with the test results shown in Table 2.

REFERENCE EXAMPLE 3

Testing is conducted according to the method in preferred embodiment 5, with the distinction that no tobacco stem fibers are added. The physical properties of the resulting tobacco sheets are tested, with the test results shown in Table 2.

TABLE 2
Effects of the quantity of tobacco stem fibers
on physical properties of tobacco sheets
	Reference
	example 3	Embodiment 5
Quantity of wood pulp	16 parts
fibers
Quantity of tobacco stem	0	0.5 part	1.0 part	2.0 parts	4.0 parts
fibers
Bulk (cm3/g)	2.09	2.07	2.13	2.17	2.16
Tensile index (N · m/g)	9.09	9.31	11.12	11.43	12.69

As can be seen from Table 2, the present invention effectively improves the bulk (after 1.0 part) and tensile index of the prepared tobacco sheets by adding tobacco stem fibers.

Preferred Embodiment 6

Testing is conducted according to the method in preferred embodiment 1, except that 12 parts of wood pulp fibers and 2.0 parts, 4.0 parts, 6.0 parts, and 8.0 parts of tobacco stem fibers are utilized, respectively, in the mixed pulp preparation. The physical properties of the tobacco sheets obtained by adding different amounts of tobacco stem fibers are tested respectively, with the test results shown in Table 3.

REFERENCE EXAMPLE 4

Testing is conducted according to the method in preferred embodiment 6, with the distinction that no tobacco stem fibers are added. The physical properties of the resulting tobacco sheets are tested, with the test results shown in Table 3.

TABLE 3
Effects of the quantity of tobacco stem fibers
on physical properties of tobacco sheets
	Reference
	example 4	Embodiment 6
Quantity of wood pulp	12 parts
fibers
Quantity of tobacco stem	0	2.0 parts	4.0 parts	6.0 parts	8.0 parts
fibers
Bulk (cm3/g)	2.14	2.10	2.18	2.17	2.16
Tensile index (N · m/g)	8.37	9.88	10.69	11.78	12.95

As can be seen from Table 3, the present invention effectively improves the bulk (after 4.0 part) and tensile index of the finally-prepared tobacco sheets by adding tobacco stem fibers.

As evidenced by the above mentioned preferred embodiments, by adding tobacco stem fibers the present invention effectively reduces the quantity of wood pulp fibers, ensuring the continuous operation of the paper machine and effectively improving the bulk and tensile index of prepared tobacco sheets. Furthermore, by reducing the quantity of wood pulp fibers, the present invention improves the flavor of tobacco, effectively relieving the negative effect of excessive wood pulp fibers on the flavor of tobacco.

The foregoing descriptions are only preferred embodiments of the present invention. It should be noted that for one ordinary skilled in the art, several improvements and modifications may further be made without departing from the principle of the present invention. These improvements and modifications should also be deemed as falling within the protection scope of the present invention.

Claims

1. A preparation method of tobacco sheets with a reduced quantity of wood pulp fibers, comprising the following steps:

(1) cooking tobacco stem materials by alkaline process, and filtering and washing the cooked tobacco stem materials to obtain tobacco stem fibers; and

(2) generating mixed pulp by mixing wood pulp fibers, tobacco pulp, filling materials, water and the tobacco stem fibers obtained in step (1) together as per certain proportions, and subjecting the mixed pulp to a papermaking process in a paper machine to obtain tobacco sheets.

2. The preparation method according to claim 1, wherein the tobacco stem fibers in step (1) have a length of 0.1-0.5 mm and a diameter of 0.5-2 μm.

3. The preparation method according to claim 1, wherein in step (1), strong alkali, the tobacco stem materials and water are mixed and then cooked, the strong alkali has a mass concentration of 15-50%, and a mass ratio of the tobacco stem materials to the strong alkali is (4.5-5.5):1.

4. The preparation method according to claim 2, wherein in step (1), strong alkali, the tobacco stem materials and water are mixed and then cooked, the strong alkali has a mass concentration of 15-50%, a mass ratio of the tobacco stem materials to the strong alkali is (4.5-5.5):1.

5. The preparation method according to claim 1, wherein in step (1), the cooking is conducted at a temperature of 150-180° C. for a time of 1-4 h.

6. The preparation method according to claim 2, wherein in step (1), the cooking is conducted at a temperature of 150-180° C. and a time of cooking is 1-4 h.

7. The preparation method according to claim 1, wherein in step (2), the tobacco stem fibers in the mixed pulp have a mass content of 0.1-3%.

8. The preparation method according to claim 1, wherein in step (2), the wood pulp fibers in the mixed pulp have a mass content of 14-22%.

9. The preparation method according to claim 7, wherein in step (2), the wood pulp fibers in the mixed pulp have a mass content of 14-22%.

10. The preparation method according to claim 1, wherein in step (2), the filling materials comprise calcium carbonate.

11. The preparation method according to claim 1, wherein in step (2), the filling materials in the mixed pulp have a mass content of 8-20%.

12. The preparation method according to claim 1, wherein in step (2), the filling materials comprise calcium carbonate and wherein the filling materials in the mixed pulp have a mass content of 8-20%.

13. The preparation method according to claim 1, wherein in step (2), the tobacco pulp comprises tobacco stem pulp and tobacco leaf pulp, and the tobacco pulp has a mass concentration of 5-15%.

14. The preparation method according to claim 1, wherein in step (2), the mixed pulp has a mass concentration of 0.1-1.0%.

15. The preparation method according to claim 7, wherein in step (2), the mixed pulp has a mass concentration of 0.1-1.0%.

16. The preparation method according to claim 10, wherein in step (2), the mixed pulp has a mass concentration of 0.1-1.0%.

17. The preparation method according to claim 13, wherein in step (2), the mixed pulp has a mass concentration of 0.1-1.0%.