A method for preparing impermeable and moisture-retaining cigarette paper and its product.

Abstract

This invention relates to a method for preparing impermeable and moisture-retaining cigarette paper and its product, comprising the following steps: first, plasma treatment of the inner surface of a base cigarette paper to activate the inner surface; then, deposition of an inorganic thin film barrier layer on the inner surface of the base cigarette paper by atomic layer deposition to obtain the impermeable and moisture-retaining cigarette paper; wherein the inner surface of the base cigarette paper is the side in contact with the tobacco. This invention creatively employs atomic layer deposition to form a dense oxide inorganic thin film barrier layer on the inner surface of the cigarette paper, without the need for any adhesives, and exhibits excellent uniformity and shape retention. Only a very thin barrier layer is needed to achieve excellent water retention and impermeability; it does not affect the combustion of the cigarette paper. When the cigarette is lit, the deposited barrier coating does not participate in the combustion of the fibers in the cigarette paper and remains on the surface of the ash, posing no harm to the human body.

Description

Technical Field

[0001] This invention relates to the field of cigarette paper preparation technology, specifically to a method for preparing impermeable and moisture-retaining cigarette paper, its products, and applications. Background Technology

[0002] With the improvement of people's living standards and the upgrading of the cigarette market, consumers' demands for cigarette quality are also increasing. However, traditional Chinese cigarettes generally face the challenge of rapid moisture loss and poor water retention. A decrease in moisture content severely affects their sensory characteristics, leading to increased dryness and irritation in the smoke, an unpleasant aftertaste, and a decline in sweetness. Furthermore, due to regional differences, seasonal changes, storage time, shelf life, and other factors, the moisture content of cigarettes fluctuates significantly, thus reducing the stability of cigarette quality. Therefore, cigarette moisture retention has always been a crucial area of ​​tobacco research.

[0003] Currently, cigarette humectant retention mainly relies on added humectants such as propylene glycol, glycerin, and sorbitol. However, research shows that during cigarette smoking, some humectants may migrate into the smoke, forming tar, which can affect the sensory experience of cigarettes to some extent. Meanwhile, with the development of low-tar, low-harm cigarettes, the insufficient aroma and decreased smoking comfort make the application of flavorings and fragrances in low-tar cigarettes particularly crucial. However, over time, flavoring components can easily penetrate the cigarette paper, forming colored oil stains, thus affecting the appearance of the cigarette.

[0004] Based on the above problems, developing a cigarette paper with anti-permeability and moisture-retaining functions is particularly important, and this is also a key direction in the research and development of functional cigarette paper. Currently, common methods for anti-permeability and moisture retention include adding moisture-retaining agents and organic coating agents, but these methods can easily affect the sensory experience of cigarettes and may increase the release of harmful smoke, which is detrimental to human health. CN114960269A discloses an anti-permeability aluminum foil cigarette paper, comprising a paper layer and an aluminum foil layer disposed on either side of the paper layer. The aluminum foil layer is disposed by depositing molten aluminum wire onto the surface of the paper layer using a transfer film-surface aluminizing process. The resulting anti-permeability aluminum foil cigarette paper has a thickness of 0.03-0.9 mm, and the thickness ratio of the paper layer to the aluminum foil layer is (2-25):1. It possesses good anti-permeability and moisture-proof properties, and can prevent the flavorings and fragrances in the cigarette from permeating to the outside of the anti-permeability aluminum foil cigarette. CN117867892A discloses a type of heated non-combustible cigarette paper with an aluminum ion-plated film. The ion-plating film is applied by magnetron sputtering, radio frequency sputtering, reactive sputtering, multi-arc ion or reactive evaporation methods, and the thickness of the ion-plated film is 1-10 μm. However, the cigarette papers disclosed in the above two patents are only suitable for heated cigarettes and cannot be used in traditional combustible cigarettes due to the excessive thickness of the metal film.

[0005] The present invention aims to overcome the shortcomings of the prior art and provide a brand-new anti-permeability and moisture-retaining cigarette paper to meet the market demand for high-quality cigarette paper. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing anti-permeability and moisture-retaining cigarette paper and the product thereof.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing impermeable and moisture-retaining cigarette paper, the method comprising the following steps:

[0009] (1) The inner surface of the basic cigarette paper is subjected to plasma treatment to activate the inner surface of the cigarette paper;

[0010] (2) An inorganic thin film barrier layer is deposited on the inner surface of the base cigarette paper by atomic layer deposition to obtain the impermeable and moisture-retaining cigarette paper;

[0011] The inner surface of the basic cigarette paper is the side that comes into contact with the tobacco.

[0012] This invention creatively employs atomic layer deposition to form a dense oxide inorganic thin film barrier layer on the inner surface of cigarette paper, without the need for any adhesives, thus reducing the impact of adhesives on the sensory experience of smoking cigarettes. It exhibits excellent uniformity and shape retention, requiring only a very thin barrier layer to achieve excellent water retention and anti-permeability effects. Furthermore, it does not affect the combustion of cigarette paper; when a cigarette is lit, the deposited barrier coating does not participate in the combustion of the fibers in the cigarette paper and remains on the surface of the ash, posing no harm to the human body.

[0013] Preferably, the plasma-generating gas in the plasma treatment of step (1) includes oxygen or argon.

[0014] Preferably, the flow rate of the oxygen ionizer generating gas is 8-12 sccm, such as 8 sccm, 9 sccm, 10 sccm, 11 sccm, 12 sccm, etc. Any other specific value within this range can be selected, and will not be elaborated here.

[0015] Preferably, the oxygen plasma treatment time is 8-12 minutes, such as 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, etc. Any other specific point value within this range can be selected, and will not be elaborated here.

[0016] Preferably, the voltage of the plasma treatment is 20-30V, such as 20V, 21V, 22V, 23V, 24V, 25V, 26V, 27V, 28V, 29V, 30V, etc. Any other specific value within this range can be selected, and will not be described in detail here.

[0017] Preferably, the first precursor for atomic layer deposition in step (2) is trimethylaluminum, and the second precursor is oxygen plasma.

[0018] Preferably, the introduction time of the first precursor is 0.6s or more, such as 0.6s, 0.7s, 0.8s, 0.9s, 1.0s, etc. Any other specific point value within this range can be selected, and will not be elaborated here.

[0019] Preferably, the purging time of the first precursor is 15s or more, such as 15s, 16s, 17s, 18s, 19s, 20s, etc. Any other specific point value within this range can be selected, and will not be elaborated here.

[0020] Preferably, the introduction time of the second precursor is 8s or more, such as 8s, 9s, 10s, 11s, 12s, etc. Any other specific point value within this range can be selected, and will not be elaborated here.

[0021] Preferably, the bulk purging time of the second precursor is 30s or more, such as 30s, 31s, 32s, 33s, 34s, 35s, etc. Any other specific point value within this range can be selected, and will not be elaborated here.

[0022] Preferably, the second precursor is generated by argon and oxygen through a dielectric barrier discharge.

[0023] Preferably, the discharge gap is 0.5-1.5mm (e.g., 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.), and the voltage regulator voltage is 20-30V (e.g., 20V, 21V, 22V, 23V, 24V, 25V, 26V, 27V, 28V, 29V, 30V, etc.). Any other specific value within the above range can be selected, and will not be elaborated here.

[0024] Preferably, the flow rate of the argon gas is 580-620 sccm (e.g., 580 sccm, 590 sccm, 600 sccm, 610 sccm, 620 sccm, etc.), and the flow rate of the oxygen gas is 5-15 sccm (e.g., 5 sccm, 6 sccm, 7 sccm, 8 sccm, 9 sccm, 10 sccm, 11 sccm, 12 sccm, 13 sccm, 14 sccm, 15 sccm, etc.). Any other specific point value within the above range can be selected, and will not be elaborated here.

[0025] Preferably, the deposition cycle of the atomic layer deposition is 85-260, such as 85, 90, 95, 100, 105, 110, 115, 120, 130, 140, 150, 160, 170, 180, 190, 200, 220, 240, 260, etc. Any other specific point value within this range can be selected, and will not be elaborated here.

[0026] Preferably, the inorganic thin film barrier layer in step (2) is an Al2O3 thin film.

[0027] Preferably, the thickness of the thin film barrier layer is 20-60nm, such as 20nm, 22nm, 25nm, 30nm, 32nm, 35nm, 37nm, 40nm, 42nm, 45nm, 48nm, 50nm, 52nm, 55nm, 58nm, 60nm, etc. Any other specific value within this range can be selected, and will not be elaborated here.

[0028] In a second aspect, the present invention provides an impermeable and moisture-retaining cigarette paper prepared according to any one of the preparation methods described in the first aspect.

[0029] Preferably, the basis weight of the cigarette paper is 20-40 g / m³. 2 (e.g. 20g / m 2 22g / m 2 24g / m 2 26g / m 2 28g / m 2 30g / m 2 32g / m 2 34g / m 2 36g / m 2 38g / m 2 40g / m 2The thickness is 30-100μm (30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 90μm, 100μm, etc.), and the air permeability is 40-100CU (e.g., 40CU, 45CU, 50CU, 55CU, 60CU, 65CU, 70CU, 75CU, 80CU, 85CU, 90CU, 95CU, 100CU, etc.). Any other specific point value within the above range can be selected, which will not be elaborated here.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] This invention creatively employs atomic layer deposition to form a dense oxide inorganic thin film barrier layer on the inner surface of cigarette paper, without the need for any adhesives, thus reducing the impact of adhesives on the sensory experience of smoking cigarettes. It exhibits excellent uniformity and shape retention, requiring only a very thin barrier layer to achieve excellent water retention and anti-permeability effects. Furthermore, it does not affect the combustion of cigarette paper; when a cigarette is lit, the deposited barrier coating does not participate in the combustion of the fibers in the cigarette paper and remains on the surface of the ash, posing no harm to the human body. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the cigarette paper prepared in Example 1. 1 is the basic cigarette paper, and 2 is the inorganic thin film barrier layer. Detailed Implementation

[0033] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0034] Unless otherwise specified, the reagents and consumables used in the following embodiments were purchased from conventional reagent manufacturers in the art; unless otherwise specified, the experimental methods and techniques used were conventional methods and techniques in the art.

[0035] Preparation Example

[0036] This preparation example provides a basic cigarette paper, prepared by the following method:

[0037] Following the cigarette paper manufacturing method, a sample with a basis weight of 27 g / m³ was prepared. 2 Basic cigarette paper with an air permeability of 100 CU.

[0038] Cigarette paper preparation method: using hemp pulp and wood pulp as pulp raw materials (65%), calcium carbonate as filler (32%), guar gum as retention aid (2%), and potassium citrate and sodium citrate as combustion regulators (1%), a basis weight of 27 g / m³ is prepared.2 Basic cigarette paper with an air permeability of 100 CU.

[0039] Example 1

[0040] This embodiment provides a moisture-retaining and impermeable cigarette paper, prepared by the following method:

[0041] (1) Plasma treatment was performed on the basic cigarette paper prepared in the preparation example:

[0042] The basic cigarette paper prepared in Example 1 was placed in a chamber, and oxygen was used as the plasma source. The oxygen flow rate was set to 10 sccm, the voltage regulator voltage was 25 V, and the treatment was carried out for 10 min to obtain cigarette paper with inner surface activation.

[0043] (2) Using a mixture of argon and oxygen as a plasma source, a second precursor oxygen plasma is generated by dielectric barrier discharge. The discharge gap is 1 mm, the argon flow rate is 600 sccm, the oxygen flow rate is 10 sccm, and the voltage regulator voltage is 25 V.

[0044] The inner surface-activated cigarette paper was placed in the chamber, and a vacuum was drawn to preheat the chamber to 65°C. The chamber pressure was then adjusted to Open mode, with a background pressure of 10 Pa. Trimethylaluminum was introduced into the chamber for 0.6 s, followed by a 15 s purge. Oxygen plasma was then introduced into the chamber for 8 s, followed by a 30 s purge, completing one Al2O3 film deposition cycle. After 160 cycles, an impermeable and moisture-retaining cigarette paper with an Al2O3 film thickness of 37.5 ± 2 nm was obtained.

[0045] Example 2

[0046] This embodiment provides a moisture-retaining and impermeable cigarette paper, prepared by the following method:

[0047] (1) Plasma treatment was performed on the basic cigarette paper prepared in the preparation example:

[0048] The basic cigarette paper prepared in Example 1 was placed in a chamber, and oxygen was used as the plasma source. The oxygen flow rate was set to 8 sccm, the voltage regulator voltage was 27 V, and the treatment was carried out for 12 min to obtain cigarette paper with inner surface activation.

[0049] (2) Using a mixture of argon and oxygen as a plasma source, a second precursor oxygen plasma is generated by dielectric barrier discharge. The discharge gap is 1.2 mm, the argon flow rate is 580 sccm, the oxygen flow rate is 15 sccm, and the voltage regulator voltage is 28 V.

[0050] The inner-surface activated cigarette paper was placed in the chamber, and a vacuum was drawn to preheat the chamber to 65°C. The chamber pressure was then adjusted to Open mode, with a background pressure of 10 Pa. Trimethylaluminum was introduced into the chamber for 0.8 s, followed by a 17 s purge; oxygen plasma was then introduced into the chamber for 9 s, followed by a 33 s purge, serving as one cycle for Al2O3 film deposition. After 240 cycles, an Al2O3 film with a thickness of 60 ± 1 nm was obtained, providing impermeability and moisture retention.

[0051] Example 3

[0052] This embodiment provides a moisture-retaining and impermeable cigarette paper, prepared by the following method:

[0053] (1) Plasma treatment was performed on the basic cigarette paper prepared in the preparation example:

[0054] The basic cigarette paper prepared in Example 1 was placed in a chamber, and argon was used as the plasma source. The argon flow rate was set to 12 sccm, the voltage regulator voltage was 23 V, and the treatment was carried out for 8 min to obtain cigarette paper with inner surface activation.

[0055] (2) Using a mixture of argon and oxygen as a plasma source, a second precursor oxygen plasma is generated by dielectric barrier discharge. The discharge gap is 0.8 mm, the argon flow rate is 620 sccm, the oxygen flow rate is 5 sccm, and the voltage regulator voltage is 23 V.

[0056] The inner surface-activated cigarette paper was placed in the chamber, and a vacuum was drawn to preheat the chamber to 65°C. The chamber pressure was then adjusted to Open mode, with a background pressure of 10 Pa. Trimethylaluminum was introduced into the chamber for 1.0 s, followed by a 20 s purge; oxygen plasma was then introduced into the chamber for 10 s, followed by a 35 s purge, completing one Al2O3 film deposition cycle. After 90 cycles, an Al2O3 film with a thickness of 20 ± 1 nm was obtained, providing impermeability and moisture retention.

[0057] Example 4

[0058] This embodiment provides an anti-permeability and moisture-retaining cigarette paper, which differs from Embodiment 1 only in that the deposition cycle in step (2) is 40, the thickness of the Al2O3 film is 10±1nm, and all other conditions remain unchanged.

[0059] Example 5

[0060] This embodiment provides an anti-permeability and moisture-retaining cigarette paper, which differs from Embodiment 1 only in that the deposition cycle in step (2) is 400 and the thickness of the Al2O3 film is 93±0.5nm, while other conditions remain unchanged.

[0061] Example 6

[0062] This embodiment provides a moisture-retaining and impermeable cigarette paper, which differs from Embodiment 1 only in that the introduction time of trimethylaluminum in step (2) is 0.3s, while all other conditions remain unchanged.

[0063] Example 7

[0064] This embodiment provides a moisture-retaining and impermeable cigarette paper, which differs from Embodiment 1 only in that the purging time of trimethylaluminum in step (2) is 10s, while all other conditions remain unchanged.

[0065] Example 8

[0066] This embodiment provides a permeation-proof and moisture-retaining cigarette paper, which differs from Embodiment 1 only in that the oxygen plasma introduction time in step (2) is 5s, while other conditions remain unchanged.

[0067] Example 9

[0068] This embodiment provides a permeation-proof and moisture-retaining cigarette paper, which differs from Embodiment 1 only in that the oxygen plasma purging time in step (2) is 25s, while other conditions remain unchanged.

[0069] Comparative Example 1

[0070] This comparative example provides a cigarette paper that differs from Example 1 only in that in step (2), aluminum is selected as the coating material for the inner surface of the cigarette paper, and an active reactive evaporation ion plating process is used to perform ion plating on the inner surface of the cigarette paper, with a thickness of 10 μm.

[0071] Comparative Example 2

[0072] This comparative example provides a cigarette paper that differs from Example 1 only in that in step (2), aluminum is selected as the coating material for the inner surface of the cigarette paper, and radio frequency sputtering ion plating process is used to perform ion plating on the inner surface of the cigarette paper, with a thickness of 5 μm.

[0073] Test Example 1

[0074] This test example tested the air permeability, oil resistance, and vapor transmission rate of the cigarette papers prepared in Examples 1-9 and Comparative Examples 1-2, with the base cigarette paper obtained in the preparation example serving as a blank group. The results are shown in Table 1:

[0075] (1) The air permeability of cigarette paper was tested according to GB / T 23227-2018 standard;

[0076] (2) The oil resistance rating is tested according to GB / T 22805.2-2008 standard;

[0077] (3) Moisture permeability: The water vapor permeability of cigarette paper was tested using a moisture permeability tester (TSY-T1H) at 38℃±1℃ and 90±2%RH.

[0078] Table 1

[0079]

[0080]

[0081] As shown in Table 1, the cigarette paper prepared by the method of this invention has an oil resistance rating that is improved by more than 8% compared with the basic cigarette paper, and the water vapor transmission rate is reduced by more than 1180 g / m². 2 • 24h, which greatly improves the anti-grease penetration and water vapor barrier effect of cigarette paper, while maintaining high air permeability and not affecting the combustion of cigarette paper.

[0082] Comparing Example 1 with Examples 4-5, it can be seen that when the thickness of the inorganic thin film barrier layer is within a specific range, better anti-oil penetration and water vapor barrier effects can be obtained. Too thick or too thin will affect the water vapor permeability.

[0083] Comparing Example 1 with Examples 6-9, it can be seen that the introduction time and purging time of the first and second precursors during atomic layer deposition also affect the anti-grease penetration effect and water vapor barrier effect of the prepared cigarette paper.

[0084] Comparative Examples 1 and 2 were prepared using reactive evaporation ion plating and radio frequency sputtering ion plating, respectively. The resulting ion plating films were very thick, resulting in an air permeability of 0 CU, and therefore could not be used in burning cigarettes.

[0085] Test Example 2

[0086] This test example examines the moisture retention properties of cigarette paper:

[0087] Cigarettes were prepared from the cigarette paper obtained in Examples 1-9 and placed under low humidity conditions (temperature 22±1℃ and humidity 40±2%) and high humidity conditions (temperature 22±1℃ and humidity 70±2%) for 240 hours. The moisture content of the cigarettes was measured. A blank group was set up and cigarettes were prepared using the basic cigarette paper. The results are shown in Table 2.

[0088] Table 2

[0089] Group Moisture content (%) in high humidity environments Moisture content (%) in low-humidity environments Example 1 14.9 12.8 Example 2 14.4 12.4 Example 3 13.8 11.7 Example 4 12.5 10.8 Example 5 12.9 10.5 Example 6 12.8 9.7 Example 7 13.6 11.1 Example 8 12.5 10.3 Example 9 12.9 10.9 Blank group 11.5 10.2

[0090] As shown in Table 2, the cigarette paper prepared by the method of the present invention has a good moisture retention effect in both low-humidity and high-humidity environments.

[0091] Comparing Example 1 with Examples 4-5, it can be seen that when the thickness of the inorganic thin film barrier layer is within a specific range, a better lubrication effect can be obtained.

[0092] Comparing Example 1 with Examples 6-9, it can be seen that the introduction time and purging time of the first and second precursors during atomic layer deposition also affect the moisture retention effect of the prepared cigarette paper.

[0093] Test Example 3

[0094] This test example conducts a sensory evaluation of cigarettes made from the cigarette paper prepared in Examples 1-9, and sets up a blank group. Cigarettes were prepared using the basic cigarette paper. Seven smoking experts conducted sensory evaluations of the cigarettes according to the standard of "GB 5606.4-2005 Cigarettes Part 4: Sensory Technical Requirements". The results are averaged. The sensory evaluation results are shown in Table 3.

[0095] Table 3

[0096] Group luster aroma coordination Mixed gases Irritating Aftertaste Total Score Example 1 5 28.6 5.0 10.3 18.3 21.7 88.9 Example 2 5 28.1 4.8 9.8 17.5 21.0 86.2 Example 3 5 27.8 4.9 10.1 17.6 21.3 86.7 Example 4 5 27.4 4.5 9.8 17.4 21.1 85.2 Example 5 5 26.8 4.3 9.0 17.0 19.8 81.9 Example 6 5 27.5 4.6 9.5 17.3 21.2 85.1 Example 7 5 27.6 4.7 10.1 17.6 21.3 86.3 Example 8 5 27.4 4.6 9.7 17.3 21.3 85.3 Example 9 5 27.4 4.7 10.0 17.7 20.8 85.6 Blank group 5 27.0 4.5 9.4 16.9 20.3 83.1

[0097] As shown in Table 3, the cigarette paper prepared by the method of the present invention has a good water vapor barrier effect and excellent water retention. Therefore, the prepared cigarettes have the least irritation and the highest overall sensory score.

[0098] Comparing Example 1 with Examples 4-5, it can be seen that when the thickness of the inorganic thin film barrier layer is within a specific range, a better overall sensory score for cigarettes can be obtained.

[0099] Comparing Example 1 with Examples 6-9, it can be seen that the introduction time and purging time of the first and second precursors during atomic layer deposition also affect the overall sensory score of the prepared cigarettes.

[0100] The applicant declares that the technical solution of this invention is illustrated by the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

[0101] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0102] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A method for preparing impermeable and moisture-retaining cigarette paper, characterized in that, The preparation method includes the following steps: (1) The inner surface of the basic cigarette paper is subjected to plasma treatment to activate the inner surface of the cigarette paper; The plasma-generating gas in the plasma treatment includes oxygen or argon. (2) An inorganic thin film barrier layer is deposited on the inner surface of the base cigarette paper by atomic layer deposition to obtain the impermeable and moisture-retaining cigarette paper; The inner surface of the basic cigarette paper is the side that comes into contact with the tobacco shreds; The first precursor for the atomic layer deposition is trimethylaluminum, and the second precursor is oxygen plasma; The inorganic thin film barrier layer is an Al2O3 thin film; the thickness of the inorganic thin film barrier layer is 20-60 nm.

2. The method for preparing impermeable and moisture-retaining cigarette paper according to claim 1, characterized in that, Step (1) The flow rate of the gas generated by the oxygen plasma is 8-12 sccm.

3. The method for preparing impermeable and moisture-retaining cigarette paper according to claim 1, characterized in that, The oxygen plasma treatment time for step (1) is 8-12 min.

4. The method for preparing impermeable and moisture-retaining cigarette paper according to claim 1, characterized in that, The voltage for plasma treatment is 20-30 V.

5. The method for preparing impermeable and moisture-retaining cigarette paper according to claim 1, characterized in that, The introduction time of the first precursor is 0.6 s or more.

6. The method for preparing impermeable and moisture-retaining cigarette paper according to claim 1, characterized in that, The purging time of the first precursor is more than 15 seconds.

7. The method for preparing impermeable and moisture-retaining cigarette paper according to claim 1, characterized in that, The introduction time of the second precursor is 8 seconds or more.

8. The method for preparing impermeable and moisture-retaining cigarette paper according to claim 1, characterized in that, The purging time of the second precursor is more than 30 seconds.

9. The method for preparing impermeable and moisture-retaining cigarette paper according to claim 1, characterized in that, The second precursor is generated by argon and oxygen through dielectric barrier discharge.

10. The method for preparing impermeable and moisture-retaining cigarette paper according to claim 9, characterized in that, The discharge gap is 0.5-1.5 mm, and the voltage regulator voltage is 20-30 V.

11. The method for preparing impermeable and moisture-retaining cigarette paper according to claim 9, characterized in that, The flow rate of the argon gas is 580-620 sccm, and the flow rate of the oxygen gas is 5-15 sccm.

12. The method for preparing impermeable and moisture-retaining cigarette paper according to claim 1, characterized in that, The deposition cycle for the atomic layer deposition is 85-260.

13. The impermeable and moisture-retaining cigarette paper prepared by the preparation method according to any one of claims 1-12.

14. The anti-permeability and moisture-retaining cigarette paper according to claim 13, characterized in that, The basis weight of the impermeable and moisture-retaining cigarette paper is 20-40 g / m³. 2 The thickness is 30-100 μm and the air permeability is 40-80 CU.

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