A composite tobacco sheet and its preparation method

Abstract

This invention provides a composite tobacco sheet and its preparation method, belonging to the technical field of tobacco sheet technology. The composite tobacco sheet is prepared from tobacco powder, pre-locked aroma micro-powder, water, and glycerin, etc.; the pre-locked aroma micro-powder is obtained by coating and drying natural plant micro-powder, natural plant gum, and water. This invention utilizes plant gum to form an aroma-locking film on the surface of the natural plant micro-powder, reducing the loss of plant-characteristic aromas during processing; the natural plant micro-powder acts as a rigid framework to optimize the pore structure and mechanical properties of the sheet. The composite tobacco sheet prepared by this invention has a high plant aroma retention rate, and the aroma is released evenly with each puff during smoking, without premature burst release defects, and has good smoke harmony, making it particularly suitable for heated tobacco products. This invention has a simple process, uses readily available and environmentally friendly raw materials, and is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of tobacco sheet technology, and more particularly to a composite tobacco sheet and its preparation method. Background Technology

[0002] Heated tobacco products (HNB) are a new type of tobacco product that uses an external heat source to heat the tobacco core material at a relatively low temperature (usually no higher than 350°C), releasing flavor compounds without igniting the tobacco. This heating method significantly reduces the temperature of the tobacco core, effectively inhibiting the production of large amounts of harmful organic compounds from the high-temperature combustion and decomposition of tobacco, resulting in a substantial reduction of harmful components in mainstream cigarette smoke. However, low-temperature heating also leads to insufficient flavor release in heated cigarettes, resulting in a poor taste experience and failing to meet consumer demands. Therefore, the research and application of added flavoring ingredients has become one of the core aspects of improving the quality of heated cigarettes.

[0003] Currently, the flavoring ingredients used in heated cigarettes mainly rely on traditional chemically synthesized flavorings or artificially blended flavorings. While these methods can compensate for the insufficient release of flavor substances under low-temperature heating to some extent, they still have significant limitations: First, chemically synthesized flavorings lack the natural aroma characteristics and are difficult to simulate the complex aroma layers of natural plants; second, most flavoring substances have low boiling points and are easily volatile, and the effective components are easily lost during the preparation, drying, and storage of the cigarette sheets, resulting in poor consistency in each puff; third, the addition of flavorings often involves a complex blending process, increasing the complexity and cost of the process.

[0004] To address the aforementioned issues, natural plant-based fragrance ingredients have garnered increasing attention. These ingredients offer significant advantages, including naturally harmonious aromas, environmentally friendly processing methods, and readily available resources. Among numerous natural plant ingredients, seven natural floral and spice ingredients—coriander seeds, cloves, osmanthus, Vietnamese cinnamon, nutmeg, costus root, and Damask rose—serve as core fragrance bases. These seven ingredients exhibit significant differences in aroma style and strong complementarity of their aroma components. All have been validated through tobacco industry practice, demonstrating high compatibility with the natural aroma of tobacco and allowing for the creation of rich and diverse complex aromas. Damask rose, with its unique and elegant aroma characteristics, has become an ideal raw material for developing natural plant-based heated tobacco flavoring materials. The main aroma components of Damask rose include citronellol, geraniol, and phenethyl alcohol, possessing a sweet and mellow floral character that harmonizes well with the natural aroma of tobacco.

[0005] A fundamental problem in existing technologies remains largely unresolved: the aroma components of natural plant powders undergo significant volatilization and loss during the preparation process. Experimental data shows that unprotected powders typically retain less than 50% of their key aroma components after subsequent processing. Furthermore, residual aroma continues to dissipate during room temperature storage, impacting product shelf life and quality stability.

[0006] Therefore, there is an urgent need for a technical solution that can effectively protect the aroma of plant micropowder, reduce aroma loss during processing and storage, improve the consistency of release per breath, and at the same time not damage the original sheet structure and mechanical properties. Summary of the Invention

[0007] The purpose of this invention is to provide a composite tobacco sheet and its preparation method to solve the above-mentioned technical problems.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution: The present invention provides a composite tobacco sheet, which is composed of the following components in parts by weight: 60-80 parts tobacco powder, 5-15 parts pre-locked aroma powder, 10-30 parts water, 5-15 parts glycerin, and 0-5 parts binder; The pre-locked fragrance micro powder is obtained by mixing natural plant micro powder, natural plant gum and water; The ratio of the natural plant powder, natural plant gum, and water by weight is 1:0.005~0.02:0.5~3; The natural plant micro powders include one or more of the following: coriander seed micro powder, clove micro powder, osmanthus micro powder, Vietnamese cinnamon micro powder, nutmeg micro powder, costus root micro powder, and Damask rose micro powder.

[0009] Furthermore, the D90 of the tobacco powder is 50~70μm, and the water content is 10~12%; The pre-locked fragrance micro powder has a particle size that passes through a 100-200 mesh sieve and a moisture content of <8%.

[0010] Furthermore, the pre-locked fragrance micro powder is prepared by mixing natural plant gum and water to form a glue solution, then mixing the natural plant micro powder with the glue solution and drying it.

[0011] Furthermore, the drying temperature is 50~80℃, and the drying time is 30~120min.

[0012] This invention also provides a method for preparing composite tobacco sheets, comprising the following steps: Step 1) Dry mix tobacco powder and pre-locked fragrance micro powder to obtain powder; separately take water, glycerin and binder, stir and dissolve evenly to obtain liquid binder system; Step 2) Mix the liquid binder system and powder, stir to obtain a slurry, then roll the slurry into shape and dry it to obtain composite tobacco sheet.

[0013] Furthermore, in step 2), the roller speed of the roller press is 8~10 r / min, and the roller pressing time is 2~5 min.

[0014] Furthermore, in step 2), the thickness of the wet sheet obtained after roll forming is 0.2~0.4mm.

[0015] Furthermore, in step 2), the drying temperature is 80~120℃, and the moisture content of the resulting composite tobacco sheet is 8~12%.

[0016] The beneficial effects of this invention are: This invention boasts excellent fragrance-locking and preservation effects, resulting in a high retention rate of raw material aromas. A dense fragrance-locking film is formed on the surface of micro-powdered ingredients such as coriander seeds, cloves, osmanthus, Vietnamese cinnamon, nutmeg, costus root, and Damask rose using natural plant gums. This film effectively blocks the loss of volatile characteristic aroma components such as terpenes, alcohols, phenols, and aldehydes during pulping, rolling, and high-temperature drying. Compared to directly adding uncoated natural fragrance powder, this invention significantly increases the total content of characteristic aromas from various fragrance materials while inhibiting aroma loss during storage. This addresses the pain points of high processing losses and rapid flavor degradation during shelf life for many types of natural fragrance materials.

[0017] Optimizing the microstructure of the sheet enhances its physical and mechanical properties: Pre-locked aroma-rich natural composite flavoring powder fills the gaps between tobacco particles, forming a stable, rigid skeletal structure. This structure ensures the sheet has suitable bulk and breathability while improving its tensile strength and bursting strength, reducing the risk of powder shedding and cracking. Utilizing the synergistic effect of particle size distribution and the film skeleton, this invention allows for successful sheet forming with minimal or no binder, balancing sheet porosity and draw resistance, thus solving the problem of balancing strength and breathability in traditional tobacco sheets.

[0018] Achieving a stable and gradual release of aroma, and improving consistency in each puff: The natural plant-based membrane acts as a physical barrier and slow-release agent, uniformly delaying the heat release rate of various aroma ingredients such as coriander seed, clove, osmanthus, Vietnamese cinnamon, nutmeg, costus root, and Damask rose. This completely avoids the defects of ordinary natural fragrance powders, such as an explosive release of aroma in the first few puffs and a precipitous decline in aroma later. The finished heated cigarette has a smooth complex aroma release curve, a significantly reduced coefficient of variation in release per puff, and a stable aroma profile and consistent style throughout the entire smoking process.

[0019] With a rich and diverse flavor profile and excellent sensory quality, this product boasts a blend of seven natural aromatic ingredients, creating a variety of complex aromas including floral, herbal, spicy, and woody notes. It can be flexibly formulated with single or blended ingredients to suit different consumer preferences. The various natural aromas blend harmoniously with the natural tobacco flavor, resulting in a delicate and smooth smoke with significantly reduced irritation and dryness, leaving a clean and comfortable aftertaste. The entire process uses natural raw materials instead of chemically synthesized flavorings, ensuring high product safety. The raw materials are readily available and environmentally friendly, and production costs are controllable, giving it a strong competitive advantage and significant application value in the heated tobacco sheet market.

[0020] The process is highly versatile and adaptable to the industrial production of various natural fragrance materials: This pre-locking fragrance process is well-suited for coriander seeds, cloves, osmanthus, Vietnamese cinnamon, nutmeg, costus root, and Damask rose. The preparation process is standardized and the parameters are stable. There is no need to modify the production line separately for different fragrance materials. The process is simple and easy to control, and it can quickly achieve large-scale production of multi-flavor series products. Detailed Implementation

[0021] The present invention provides a composite tobacco sheet, which is composed of the following components in parts by weight: 60-80 parts tobacco powder, 5-15 parts pre-locked aroma powder, 10-30 parts water, 5-15 parts glycerin, and 0-5 parts binder; The pre-locked fragrance micro powder is obtained by mixing natural plant micro powder, natural plant gum and water; The ratio of the natural plant powder, natural plant gum, and water by weight is 1:0.005~0.02:0.5~3; The natural plant micro powders include one or more of the following: coriander seed micro powder, clove micro powder, osmanthus micro powder, Vietnamese cinnamon micro powder, nutmeg micro powder, costus root micro powder, and Damask rose micro powder.

[0022] In this invention, the amount of tobacco powder added is preferably 70 parts by weight to ensure the strength of the sheet body and the natural aroma of tobacco. If the amount added is less than 60 parts, molding will be difficult, and if it is more than 80 parts, the aroma will be insufficient.

[0023] In this invention, the amount of the pre-locked fragrance micro powder added is preferably 8 to 12 parts by weight, more preferably 10 parts, and more than 15 parts will affect the mechanical uniformity and cost of the sheet.

[0024] In this invention, the amount of water added is preferably 15 to 25 parts by weight, and more preferably 20 parts.

[0025] In this invention, the amount of glycerin added is preferably 8 to 12 parts by weight, and more preferably 10 parts.

[0026] In this invention, the amount of binder added is preferably 3 parts by weight, so as not to affect the porosity and the sucking experience.

[0027] In this invention, the preferred ratio of the natural plant powder, natural plant gum and water is 1:0.01~0.015:1~2, and more preferably 1:0.01:2.

[0028] In this invention, the natural plant powder is preferably one or more of coriander seed powder, clove powder, osmanthus powder, Vietnamese cinnamon powder, and Damask rose powder, and more preferably one or more of coriander seed powder, Vietnamese cinnamon powder, and Damask rose powder.

[0029] In this invention, the natural plant gum includes one or more of gum arabic, guar gum, xanthan gum, gelatin and sodium alginate, preferably one or more of gum arabic, guar gum and xanthan gum, and more preferably gum arabic.

[0030] In this invention, the binder includes one or more of sodium carboxymethyl cellulose, guar gum and xanthan gum, preferably sodium carboxymethyl cellulose.

[0031] In this invention, the D90 of the tobacco powder is 50~70μm, preferably 60μm; the moisture content is 10~12%, preferably 11%; The particle size of the pre-locked fragrance micro powder is sieved through a 100-200 mesh sieve, preferably through a 130-180 mesh sieve; the moisture content is <8%, preferably <5%.

[0032] In this invention, the natural plant micro-powder acts as rigid skeletal particles in the sheet. During rolling and drying, micro-gaps and pores naturally form around the micro-powder particles. This invention strictly limits the particle size of the tobacco powder and the pre-locked fragrance micro-powder, forming a coarse-fine particle gradation system: the fine-particle micro-powder is precisely embedded in the gaps of the large-particle tobacco powder, optimizing the particle packing and arrangement. This avoids both excessive large gaps causing the sheet to become loose and shed powder, and excessively fine particles causing the sheet to become dense and less breathable due to full filling and compaction. The precise particle size matching works synergistically with the rigid skeletal structure of the adhesive film, significantly improving the tensile and bursting properties of the sheet with the same amount of binder, solving the dilemma of conventional sheets either having poor strength or insufficient breathability.

[0033] In this invention, the pre-locked fragrance micro powder is prepared by mixing natural plant gum and water to form a syrup, then mixing the natural plant micro powder with the syrup and drying it.

[0034] In this invention, the drying temperature is 50~80℃, preferably 60~70℃; the drying time is 30~120min, preferably 50~100min, and more preferably 70~80min.

[0035] This invention also provides a method for preparing composite tobacco sheets, comprising the following steps: Step 1) Dry mix tobacco powder and pre-locked fragrance micro powder to obtain powder; separately take water, glycerin and binder, stir and dissolve evenly to obtain liquid binder system; Step 2) Mix the liquid binder system and powder, stir to obtain a slurry, then roll the slurry into shape and dry it to obtain composite tobacco sheet.

[0036] In this invention, in step 2), the roller speed of the roller pressing is 8~10 r / min, preferably 9 r / min; the roller pressing time is 2~5 min, preferably 3~4 min.

[0037] In this invention, in step 2), the thickness of the wet sheet obtained after roll forming is 0.2~0.4mm, preferably 0.3mm.

[0038] In this invention, in step 2), the drying temperature is 80~120℃, preferably 100℃; the moisture content of the composite tobacco sheet obtained after drying is 8~12%, preferably 10%.

[0039] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0040] Example 1

[0041] Mix 0.01 parts of gum arabic and 2 parts of water, stir at room temperature for 10 minutes until completely dissolved, and prepare a uniform solution; mix 1 part of Damask rose micro powder with the solution, stir continuously for 20 minutes until the materials are uniformly mixed, then dry at 65°C for 75 minutes, cool and pulverize through a 150-mesh sieve to obtain pre-locked fragrance micro powder. Add 70 parts of tobacco powder and 10 parts of pre-locked fragrance micro powder to a dry powder mixer and dry mix at room temperature for 15 minutes to obtain a composite powder. Separately, add 20 parts of water, 10 parts of glycerol, and 3 parts of sodium carboxymethyl cellulose to a mixing tank and stir at room temperature for 25 minutes until completely dissolved to obtain a transparent and uniform liquid binder system.

[0042] The prepared liquid binder system is slowly sprayed into the composite powder and stirred continuously for 30 minutes to prepare a uniform, lump-free slurry. The slurry is then fed into a roller press, with the roller speed set to 9 r / min and the pressing time to 3.5 minutes. The roller press is then formed into a wet sheet with a thickness of 0.3 mm. The wet sheet is then placed in a drying equipment and dried at 100°C until the moisture content of the sheet is 10%. After drying, the thickness of the finished sheet is 0.2 mm. After cooling, it is cut into neat pieces to obtain the finished composite tobacco sheet.

[0043] Example 2

[0044] Mix 0.015 parts of gum arabic with 3 parts of water and stir at room temperature for 12 minutes until completely dissolved to prepare a uniform solution; mix 1 part of Damask rose micro powder with the solution and stir continuously for 20 minutes until the materials are uniformly mixed, then dry at 70°C for 75 minutes, cool and pulverize through a 150-mesh sieve to obtain pre-locked fragrance micro powder. 80 parts of tobacco powder and 15 parts of pre-locked fragrance micro powder were dry-mixed for 20 minutes to obtain a uniform composite powder; 25 parts of water, 12 parts of glycerol and 5 parts of sodium carboxymethyl cellulose were mixed and stirred at room temperature for 30 minutes until completely dissolved to obtain a liquid binder system.

[0045] The liquid binder system was mixed with the composite powder for 35 minutes to obtain a fine slurry. A 0.40 mm thick wet sheet was formed by rolling at 10 r / min for 4 minutes. The formed wet sheet was then dried at a constant temperature of 110℃, controlling the final moisture content of the composite tobacco sheet to be 12%. The thickness of the dried sheet was 0.35 mm. After cooling and cutting, the finished product was obtained.

[0046] Example 3

[0047] Mix 0.01 parts of gum arabic with 1 part of water and stir at room temperature for 8 minutes until completely dissolved to prepare a uniform solution; mix 1 part of Damask rose micro powder with the solution and stir continuously for 15 minutes until the materials are uniformly mixed, then dry at 60°C for 70 minutes, cool and pulverize through a 130-mesh sieve to obtain pre-locked fragrance micro powder. Mix 60 parts of tobacco powder with 5 parts of pre-locked fragrance micro powder for 10 minutes to obtain a composite powder; take 15 parts of water and 8 parts of glycerin, stir at room temperature for 20 minutes to mix evenly to obtain a binder-free liquid system.

[0048] The liquid system and the composite powder were mixed and stirred for 25 minutes to prepare a uniform slurry. The roller speed was set to 8 r / min and the roller was pressed for 2 minutes to form a 0.20 mm thick wet sheet. The formed wet sheet was placed under a constant temperature of 90℃ to dry, and the moisture content of the final composite tobacco sheet was controlled to be 8%. The thickness of the finished sheet after drying was 0.10 mm. After cooling and cutting, the composite tobacco sheet was obtained.

[0049] Comparative Example 1

[0050] Compared to Example 1, the addition of pre-locked rose micro powder was omitted.

[0051] Comparative Example 2

[0052] Compared to Example 1, untreated rose micropowder was added.

[0053] Performance testing

[0054] 1) Physical performance testing

[0055] Test method: The sample was equilibrated at a temperature of (23±1)℃ and a relative humidity of (30±2)% for at least 8 hours. Quantification was performed according to GB / T 451.2-2023. The thickness shall be determined according to GB / T 451.3-2002, and the tightness shall be calculated based on the basis weight and thickness. Tensile strength was determined using a tensile strength tester according to GB / T 12914-2018; The bursting strength was determined using a bursting strength tester according to GB / T 454-2020.

[0056] Table 1. Physical property characterization of products obtained in Examples 1-3 and Comparative Examples 1-2

[0057] 2) Release behavior test of sheet material

[0058] Heated cigarettes were smoked using a rotary smoking machine. Smoking parameters: 55 mL smoke volume, 2 s duration, 30 s interval, 8 puffs, bell-shaped smoke curve. Particulate matter from the mainstream smoke of 6 heated cigarettes per group was collected using a Cambridge filter. After smoking, the Cambridge filter was folded in half, the filter was wiped clean, and placed in a 100 mL sample vial. 10 mL of anhydrous ethanol solution (containing 10 μg / mL phenylethyl acetate) was added, and the mixture was ultrasonically extracted for 30 min, concentrated to 1 mL, filtered through an organic phase microporous membrane, and analyzed by GC / MS.

[0059] Remove the tobacco from the heated cigarette, mechanically pulverize it, and pass it through a 40-mesh sieve to obtain tobacco powder. Weigh 2g of tobacco powder and place it in a 100mL stoppered conical flask, add 10mL of anhydrous ethanol solution (containing 10μg / mL phenylethyl phenylacetate), ultrasonically extract for 30min, shake well, concentrate to 1ml, filter through an organic phase microporous membrane, and perform GC / MS analysis.

[0060] Table 2 Initial aroma content (μg / piece) in the composite films obtained in Examples 1-3 and Comparative Examples 1-2

[0061] 3) Measurement of transfer behavior

[0062] The puff-by-puff release of characteristic aroma components from heated cigarettes in the mainstream particulate matter and their mass fraction in cigarette sheets were determined. Quantification was performed using the internal standard correction method: the amount of the self-standard compound = (peak area of ​​the target compound / peak area of ​​the internal standard) × (mass of the internal standard / number of cigarettes). Specifically, when calculating the release in the aerosol, the number of cigarettes was 6; when calculating the mass fraction in the tobacco, the number of cigarettes was 8. Triple parallel determinations were performed, and the average value was taken. The puff-by-puff release R and puff-by-puff transfer rate T of the characteristic aroma components were calculated according to the formula.N And the total transfer rate T. The calculation formula is as follows: Oral release: R N =R AN Port-to-port transfer rate: T N =R AN / C mA ×100% Total transfer rate: T=R A / C mA ×100% R AN R represents the amount of this component released in the Nth puff of flavored cigarette smoke (μg / cigarette); A The total release of this component in heated cigarette smoke (μg / cigarette); C mA The content of this component in the composite film (μg / piece).

[0063] Table 3. Total mainstream flue gas emission and total transfer rate in Examples 1-3 and Comparative Examples 1-2

[0064] Table 4. Characterization data of the transfer behavior of the composite sheets obtained in Examples 1-3 and Comparative Example 2.

[0065] Comparative Example 2 showed the highest release on the first puff, with an initial burst of aroma followed by a rapid decline, exhibiting a pattern of strong initial release followed by weaker release. Example 1 showed the best pre-locked aroma for sustained release, with the peak value occurring on the fourth puff, and stable release across all puffs, with a coefficient of variation of 28.6%. In Example 2, the film was too thick, and in Example 3, the film integrity was insufficient, resulting in a sequential decrease in sustained release effect.

[0066] 4) Sensory quality evaluation

[0067] The composite tobacco sheets were rolled into heated cigarette samples. All samples were placed in a constant humidity chamber (temperature 22±1℃, relative humidity 60%±2%) for 48 hours to equilibrate. Then, three experts with cigarette sensory evaluation qualifications evaluated the sensory quality of the samples. The sensory quality evaluation of heated cigarettes was conducted through six indicators, including aroma, smoke, and irritation, with a maximum score of 10 points for each indicator.

[0068] Table 5 Sensory quality evaluation scores of cigarette samples obtained in Examples 1-3 and Comparative Examples 1-2

[0069] As shown in the table, Example 1 exhibits a rich and natural rose aroma that blends exceptionally well with the natural tobacco aroma, highlighting a prominent honey sweetness; the smoke is smooth and delicate, almost without any irritation, with a significantly reduced dryness and a clean, sweet aftertaste. Overall, it boasts the best sensory quality. Example 2 has an overpowering rose aroma that slightly masks the natural tobacco aroma; the smoke is somewhat rough, with a slight astringency in the middle and later stages. Example 3 has a relatively weak rose aroma, not significantly different from the blank sample; the improvement in irritation and dryness is not obvious. Comparative Example 2 has a decent aroma in the first two puffs, but it decays quickly; the later puffs exhibit woody and off-flavors, resulting in poor harmony.

[0070] As can be seen from the above embodiments, the present invention provides a composite tobacco sheet and its preparation method. The present invention prepares pre-locked aroma-locking natural plant micro-powder by coating with natural plant gum. On the one hand, the gum film barrier significantly reduces the volatilization loss of plant characteristic aromas during sheet processing, and relies on the slow release of the gum film to achieve a stable release of aroma with each puff, overcoming the defects of conventional addition of bare plant powder, such as strong aroma at the beginning and weak aroma at the end, and poor puff consistency. On the other hand, by limiting the particle size parameters of tobacco powder and plant micro-powder, a rigid skeleton structure is constructed using the particle size distribution of coarse and fine powders. This optimizes the pore distribution of the sheet, ensures air permeability, and significantly improves the tensile strength, burst strength, and other mechanical properties of the sheet, achieving stable molding with little or no binder. The seven natural flavoring materials can be used alone or in any combination to create a diversified flavor system including floral, herbal, spicy, and woody aromas. The aroma is rich in layers, harmoniously integrated with the natural aroma of tobacco, and the finished smoke is delicate and smooth, with significantly reduced irritation and dryness, resulting in an excellent sensory experience. This invention uses all natural raw materials, avoiding the drawbacks of chemically synthesized flavorings. The raw materials are green and readily available, the formulation is highly flexible, and the preparation process is simple and controllable. It is suitable for heated tobacco products with different flavor profiles, possessing technological advantages, cost advantages, and market differentiation advantages, and has extremely high industrial promotion and application value. Experimental results show that the composite tobacco sheet prepared by this invention has a high aroma retention rate, a harmonious and mellow smoke, and excellent sensory quality, meeting the needs of heated tobacco products. The formulation and preparation process are simple and controllable, demonstrating good prospects for industrial application.

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A composite tobacco sheet, characterized in that, It consists of the following components in parts by weight: 60-80 parts tobacco powder, 5-15 parts pre-locked fragrance powder, 10-30 parts water, 5-15 parts glycerin, and 0-5 parts binder.

2. The composite tobacco sheet according to claim 1, characterized in that, The pre-locked fragrance micro powder is prepared by mixing natural plant gum and water to form a slurry, then mixing the natural plant micro powder with the slurry and drying it; by mass parts, the ratio of the natural plant micro powder, natural plant gum and water is 1:0.005~0.02:0.5~3.

3. The composite tobacco sheet according to claim 1, characterized in that, The tobacco powder has a D90 of 50-70 μm and a moisture content of 10-12%.

4. The composite tobacco sheet according to claim 1, characterized in that, The pre-locked fragrance micro powder has a particle size that passes through a 100-200 mesh sieve and a moisture content of <8%.

5. The composite tobacco sheet according to claim 2, characterized in that, The natural plant micro powders include one or more of the following: coriander seed micro powder, clove micro powder, osmanthus micro powder, Vietnamese cinnamon micro powder, nutmeg micro powder, costus root micro powder, and Damask rose micro powder.

6. The composite tobacco sheet according to claim 2, characterized in that, The drying temperature is 50~80℃, and the drying time is 30~120min.

7. The method for preparing the composite tobacco sheet according to any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1) Dry mix tobacco powder and pre-locked fragrance micro powder to obtain powder; separately take water, glycerin and binder, stir and dissolve evenly to obtain liquid binder system; Step 2) Mix the liquid binder system and powder, stir to obtain a slurry, then roll the slurry into shape and dry it to obtain composite tobacco sheet.

8. The method for preparing composite tobacco sheets according to claim 7, characterized in that, In step 2), the roller speed of the roller pressing is 8~10 r / min, and the roller pressing time is 2~5 min.

9. The method for preparing composite tobacco sheets according to claim 8, characterized in that, In step 2), after roll forming, the thickness of the resulting wet sheet is 0.2~0.4mm.

10. The method for preparing composite tobacco sheets according to claim 7, characterized in that, In step 2), the drying temperature is 80~120℃, and the moisture content of the resulting composite tobacco sheet is 8~12%.

Images