Reconstituted tobacco with moisture absorption performance adjusting and heat conduction functions and preparation method thereof

Abstract

The invention discloses reconstituted tobacco with the moisture absorption performance adjusting and heat conduction functions and a preparation method thereof.The preparation method of the reconstituted tobacco with the moisture absorption performance adjusting and heat conduction functions comprises the following steps that tobacco powder raw materials are placed in a vibration screening machine to pass through a 100-mesh sieve for use; the preparation method comprises the following steps: weighing a certain amount of tobacco powder particles, on the basis of the mass of the tobacco powder, weighing 20% by mass of a smoke agent, 4% by mass of CMC, 4.5% by mass of cellulose nanofibers and 550% by mass of water, and fully stirring and uniformly mixing the materials; wherein the smoke agent is a glycerol-graphene oxide compound; placing the slurry on the surface of a workbench of a coating tester, adjusting a gap between knife rollers to uniformly disperse the slurry, and baking; and shredding and curling to prepare the reconstituted tobacco with moisture absorption performance adjustment and heat conduction functions. The problem of non-uniform smoke release caused by high hygroscopicity of reconstituted tobacco in heated cigarettes is solved, meanwhile, the heat conduction performance of the reconstituted tobacco is improved, and the smoke quality and smoking experience are improved.

Description

Technical Field

[0001] The invention relates to the technical field of cigarette processing, and in particular to a reconstituted tobacco leaf having both hygroscopicity regulating and heat conducting functions and a preparation method thereof. Background Art

[0002] As a new tobacco product, heated cigarettes have a similar appearance, smoke, taste and feel to cigarettes, and the harmful components to the human body are far lower than traditional cigarettes, so they are favored by consumers. Due to the late start, weak research foundation, patent restrictions and other reasons, there is still a big gap between Chinese heated cigarettes and international leading products. Among them, the problem of smoke quality is particularly prominent: in order to achieve the release of flavor components at 300°C, the amount of smoke agents such as glycerin and propylene glycol added to heated cigarettes is as high as 20%, which is greater than international leading products such as IQOS. Due to the polyhydroxy structure of glycerin and propylene glycol, reconstituted tobacco leaves are extremely susceptible to moisture, the moisture content increases, the total smoke release of heated cigarettes decreases, the uniformity and stability of smoke release is low, the storage period of a single package is short (less than 24 hours at room temperature and 50% humidity), and the smoking experience is poor.

[0003] Therefore, how to reduce the hygroscopic properties of existing smoke-generating agents while improving the thermal conductivity of reconstituted tobacco leaves has become an important problem that needs to be solved urgently in this field. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a reconstituted tobacco leaf with both hygroscopicity regulating and thermal conductivity functions and a preparation method thereof, aiming to solve the problem of uneven smoke release caused by the high hygroscopicity of the reconstituted tobacco leaf in heated cigarettes, while improving its thermal conductivity to improve the smoke quality and smoking experience.

[0005] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] A method for preparing reconstituted tobacco leaves having both hygroscopicity regulating and heat conducting functions, comprising the following steps:

[0007] (1) Place the tobacco powder raw material in a vibrating sieving machine and pass it through a 100-mesh sieve for later use;

[0008] (2) Weigh a certain amount of smoke powder particles, and based on the mass of the smoke powder, weigh 20% of a smoke agent, 4% of CMC, 4.5% of nanocellulose, and 550% of water, and stir the above materials thoroughly to mix them evenly; wherein the smoke agent is a glycerol-graphene oxide composite;

[0009] (3) Place the slurry on the workbench surface of the coating test machine, adjust the gap between the knife and roller to make it evenly dispersed, and bake;

[0010] (4) Cutting and curling to produce reconstituted tobacco leaves with both hygroscopicity regulating and heat conducting functions.

[0011] Preferably, in the above technical solution, in step (2), the mass proportion of the glycerol-graphene oxide composite in the smoke generating agent is 80-100%.

[0012] Preferably, in the above technical solution, in step (2), the mass ratio of the glycerol-graphene oxide composite to propylene glycol in the smoke generating agent is 4:1.

[0013] Preferably, in the above technical solution, the glycerol-graphene oxide composite is prepared by a solution blending method, and graphene oxide and glycerol are combined by non-covalent interaction.

[0014] Preferably, in the above technical solution, the glycerol-graphene oxide composite is prepared by the following method:

[0015] While being continuously stirred by a magnetic stirrer, graphene oxide is added to glycerol in batches, and the stirring is continued followed by ultrasonication to make the graphene oxide evenly dispersed in the glycerol solution to form a suspension of a glycerol-graphene oxide composite.

[0016] Preferably, in the above technical solution, the molar ratio of graphene oxide to propylene glycol is: 1:(1.0-1.2); the ultrasonic conditions are: ultrasonic frequency 40-60 Hz, ultrasonic time 30-45 min.

[0017] Preferably, in the above technical solution, in step (3), the gap between the knife and the roller is 1.2 mm, and the baking conditions are: temperature is 90° C., and baking time is 15 to 20 min.

[0018] A reconstituted tobacco leaf having both hygroscopicity regulating and heat conducting functions is prepared according to the above-mentioned preparation method.

[0019] The invention discloses an application of a reconstituted tobacco leaf having both hygroscopicity regulating properties and heat conducting functions in heated cigarettes.

[0020] The above technical solution of the present invention has the following beneficial effects:

[0021] This application combines the existing smoke-generating agent (propylene glycol / glycerol) of new tobacco products with graphene oxide through a chemical synthesis method to innovatively synthesize a polyol-graphene oxide composite. The synthesized polyol-graphene oxide composite replaces the existing smoke-generating agent propylene glycol / glycerol. On the one hand, the hydroxyl groups in the polyol can form hydrogen bonds with the carboxyl groups and carbon atoms on the surface of graphene oxide, reducing the number of hydroxyl groups and weakening its ability to lock moisture. At the same time, the interaction between graphene oxide and polyols is enhanced, and the stability of graphene oxide is improved; on the other hand, graphene oxide can improve the thermal conductivity of reconstituted tobacco leaves and increase the amount of smoke. At the same time, cellulose nanofibers are used to replace wood outer fibers in the flake production formula to improve the physical properties of reconstituted tobacco leaves, providing technical support for the development of heat-not-burn tobacco products. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0023] Figure 1 Moisture content of reconstituted tobacco samples at different times (22±1°C, RH=32±2% (a), RH=84±2% (b)).

[0024] Figure 2 The transverse relaxation time distribution curves of the reconstituted tobacco leaf samples (22±1°C, RH=32±2% (a), RH=84±2% (b)). DETAILED DESCRIPTION

[0025] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0026] Unless otherwise specified, the reagents used in this application are all commercially available or obtained through commercial channels, or can be prepared by referring to existing chemical methods.

[0027] Example 1

[0028] Preparation of polyol-graphene oxide composites:

[0029] The method is prepared by a relatively simple solution blending method, and graphene oxide and polyol are combined through non-covalent interactions such as hydrogen bonding and electrostatics. A certain amount of glycerol is added to the reaction vessel, and the reactor temperature is controlled to be 40-60°C. Under continuous stirring, graphene oxide is added to the glycerol in batches, and stirring is continued and ultrasonicated to make the graphene oxide evenly dispersed in the glycerol solution to form a glycerol-graphene oxide composite suspension, which is then rotary evaporated to remove general water and set aside.

[0030] Example 2

[0031] The thick slurry method is adopted to produce reconstituted tobacco (A), in which the mass fraction of the smoke-generating agent is 20%, the proportion of the glycerol-graphene oxide composite (prepared by the method of Example 1) is 16% (pure substance proportion, the same below), and the proportion of propylene glycol is 4%.

[0032] (1) Place the tobacco powder raw material in a vibrating sieving machine and pass it through a 100-mesh sieve for later use;

[0033] (2) Weigh a certain amount of smoke powder particles, based on the mass of the smoke powder, weigh 20% of the smoke agent (16% of the glycerol-graphene oxide composite and 4% of propylene glycol), 4% of CMC, 4.5% of cellulose nanocellulose (absolutely dry), and 550% of water, and stir the above materials thoroughly to mix them evenly;

[0034] (3) The slurry was placed on the workbench surface of the coating test machine, and the gap between the blade and roller was adjusted to 1.2 mm to make it evenly dispersed. The temperature was set to 90° C. and baked for 15 to 20 minutes. The slurry was cut into shreds and curled to make reconstituted tobacco leaf A.

[0035] Example 3

[0036] The reconstituted tobacco leaf B was produced by the thick slurry production process, and the smoking agent with a mass fraction of 20% was a glycerol-graphene oxide composite (prepared by the method of Example 1).

[0037] (1) Place the tobacco powder raw material in a vibrating sieving machine and pass it through a 100-mesh sieve for later use;

[0038] (2) Weigh a certain amount of smoke powder particles, based on the mass of the smoke powder, weigh 20% of the smoke agent (glycerol-graphene oxide composite), 4% of CMC, 4.5% of cellulose nanocellulose (absolutely dry), and 550% of water, and stir the above materials thoroughly to mix them evenly;

[0039] (3) The slurry was placed on the workbench surface of the coating test machine, and the gap between the blade and roller was adjusted to 1.2 mm to make it evenly dispersed. The temperature was set to 90°C, and the slurry was baked for 15 to 20 minutes. The slurry was cut into shreds and curled to make reconstituted tobacco leaf B.

[0040] Comparative Example 1

[0041] Preparation of reconstituted tobacco (KB):

[0042] The reconstituted tobacco (KB) is produced by a thick slurry production process, wherein the mass fraction of the smoke-generating agent is 20%, the proportion of glycerol is 16%, and the proportion of propylene glycol is 4%.

[0043] (1) Place the tobacco powder raw material in a vibrating sieving machine and pass it through a 100-mesh sieve for later use;

[0044] (2) Weigh a certain amount of smoke powder particles, based on the mass of the smoke powder, weigh 20% of a smoke agent (including 16% of glycerol and 4% of propylene glycol), 4% of CMC, 4.5% of wood pulp fiber (absolutely dry), and 550% of water, and stir the above materials thoroughly to mix them evenly;

[0045] (3) The slurry is placed on the workbench surface of the coating test machine, and the gap between the knife and roller is adjusted to 1.2 mm to make it evenly dispersed. The temperature is set to 90°C, and the slurry is baked for 15 to 20 minutes. The slurry is cut into shreds and curled to make reconstituted tobacco KB.

[0046] Physical properties test of reconstituted tobacco leaves:

[0047] Table 1 Test results of physical indexes of reconstituted tobacco leaves by thick pulp method

[0048]

[0049]

[0050] As can be seen from Table 1, after replacing wood outer fibers with cellulose nanofibers, the tensile strength and bulk of the reconstituted tobacco leaves are significantly improved. This is because cellulose nanofibers have a high specific surface area, a high Young's modulus, and a super strong adsorption capacity, which can bond fine particles such as tobacco powder together, and can make the reconstituted tobacco products have high tensile strength and bulk; the thermal conductivity of the reconstituted tobacco leaves was tested, and the results showed that after replacing propylene glycol or propylene glycol with propylene glycol-graphene oxide, the thermal conductivity of the reconstituted tobacco leaves was greatly improved. This may be due to the dense accumulation of graphene oxide on the surface of the reconstituted tobacco leaves, which is conducive to the improvement of thermal conductivity. All of these make the reconstituted tobacco leaves react quickly under low-temperature heating conditions and can evenly release flavor substances.

[0051] Evaluation of hygroscopicity of three types of reconstituted tobacco leaves:

[0052] The above-mentioned reconstituted tobacco leaves were placed in a constant temperature and humidity chamber (temperature 22°C, relative humidity 60%) for 72 hours of equilibrium, and then cut into shreds by a shredder; the balanced thin slices were divided into 3 groups, one of which was used to determine the initial moisture content of the thin slices; at the same time, the remaining two groups were placed in a dryer containing saturated magnesium chloride (22±1°C, RH=(32±2)%) and saturated potassium chloride (22±1°C, RH=(84±2)%) solutions for desorption and moisture absorption experiments. Samples were taken out at regular intervals, accurately weighed and recorded, and the moisture content of samples at different times was calculated based on the moisture changes during storage.

[0053] The results are as follows Figure 1 As shown, from Figure 1 It can be seen that the dry basis moisture content of the three groups of reconstituted tobacco leaf samples under low humidity environment decreased with the extension of desorption time, showing almost the same downward trend within the first 16 hours, and all reached equilibrium at 100 hours. Under high humidity environment, the moisture content showed a linear upward trend over time, gradually slowed down after 60 hours, and tended to equilibrium at 100 hours. The moisture retention and hygroscopicity of samples A and B were lower than those of KB. This is because the highly hygroscopic glycerol can bind water molecules through hydrogen bonding, enhancing the affinity and adsorption capacity of thin sheets for water. Compared with glycerol, the number of hydroxyl groups in glycerol-graphene oxide is reduced, and the number of hydrogen bonds formed is reduced, which reduces the strong hygroscopicity of glycerol, and at the same time has a certain moisture-proof and moisturizing ability. The moisturizing ability of sample B is equivalent to that of sample A, but the hygroscopicity is significantly lower than that of sample A. This is because 4% propylene glycol is also added to sample A, and compared with propylene glycol, the hydrogen bonds of the hydroxyl groups in propylene glycol-graphene oxide are formed with the carboxyl groups in graphene oxide, which reduces the chance of bonding with water molecules and reduces the hygroscopicity.

[0054] The moisture distribution of reconstituted tobacco with glycerol-graphene oxide added in different humidity environments (RH = 32% (a), RH = 84% (b)) is shown in the figure. Figure 2 .from Figure 2 It can be seen that the bound water peak is dominant in the two states of water, and the proportion content is KB>B>A. These results can be explained by the fact that glycerol has more free hydroxyl groups than polyol-graphene, which results in more hydrogen bonds between reconstituted tobacco and water. This strengthens the binding force between water molecules and the reconstituted tobacco matrix, promotes the interaction between tobacco and water molecules, increases the relative content of bound water, and enhances the hygroscopicity of reconstituted tobacco. Under high RH and low RH conditions, the bound water peak area of ​​sample B is higher than that of sample A, indicating that more water in sample B is in a bound state, so sample B has lower hygroscopicity, and its moisture retention performance is comparable to that of sample A.

[0055] Sensory evaluation:

[0056] The reconstituted tobacco shreds prepared by the above process were rolled into cigarette cartridges in a disordered manner, respectively recorded as blank cigarette cartridges (made from reconstituted tobacco leaves KB), cigarette cartridges A (made from reconstituted tobacco leaves A), and cigarette cartridges B (made from reconstituted tobacco leaves B). The sensory quality of the prepared cigarette cartridges was evaluated according to the sensory evaluation requirements of the heated cigarettes of the Shanghai Institute. The results are shown in Table 2.

[0057] Table 2 Sensory quality evaluation results of thick pulp reconstituted tobacco

[0058] sample Smoke volume Aroma Momentum Coordination Irritant Taste Total score KB cigarette cartridge 6.5 23.5 7.0 7.5 12.0 21.0 77.5 Cigarette Cartridge A 7.5 25.0 7.5 8.0 13.0 22.5 83.5 Cigarette Cartridge B 8.0 26.0 7.5 8.0 13.0 22.0 86.0

[0059] As can be seen from Table 2, compared with cartridge KB, the smoke volume, aroma, flavor, strength, and taste of cartridges A and B are significantly improved, the irritation is reduced, the consistency of each puff is better, and they have good application prospects.

[0060] Although the present invention has been disclosed as above by the embodiments, it is not intended to limit the present invention. Any person skilled in the art may make various choices and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention is limited by the claims and their equivalents.

Claims

1. A method for preparing reconstituted tobacco leaves having both hygroscopicity regulating and heat conducting functions, characterized in that: The following steps are involved: (1) Place the tobacco powder raw material in a vibrating sieving machine and pass it through a 100-mesh sieve for later use; (2) Weighing a certain amount of smoke powder particles, based on the mass of the smoke powder, weighing 20% ​​of a smoke agent, 4% of CMC, 4.5% of cellulose nanofibers (CNF), and 550% of water by mass, and fully stirring the above materials to mix them evenly; the smoke agent contains a glycerol-graphene oxide composite; (3) Place the slurry on the workbench surface of the coating test machine, adjust the gap between the knife and roller to make it evenly dispersed, and bake; (4) Cutting and curling to produce reconstituted tobacco leaves with both hygroscopicity regulating and heat conducting functions.

2. The method for preparing reconstituted tobacco leaves having both hygroscopicity regulating and heat conducting functions according to claim 1, characterized in that: In step (2), the mass proportion of the glycerol-graphene oxide composite in the smoke generating agent is 80 to 100%.

3. The method for preparing reconstituted tobacco leaves having both hygroscopicity regulating and heat conducting functions according to claim 1, characterized in that: In step (2), the mass ratio of the glycerol-graphene oxide composite to propylene glycol in the smoke generating agent is 4:

1.

4. The method for preparing reconstituted tobacco leaves having both hygroscopicity regulating and heat conducting functions according to claim 2 or 3, characterized in that: The glycerol-graphene oxide composite is prepared by a solution blending method, and graphene oxide and glycerol are combined by non-covalent action.

5. The method for preparing reconstituted tobacco leaves having both hygroscopicity regulating and heat conducting functions according to claim 4, characterized in that: The glycerol-graphene oxide composite is prepared by the following method: While being continuously stirred by a magnetic stirrer, graphene oxide is added to glycerol in batches, and the stirring is continued followed by ultrasonication to make the graphene oxide evenly dispersed in the glycerol solution to form a suspension of a glycerol-graphene oxide composite.

6. The method for preparing reconstituted tobacco leaves having both hygroscopicity regulating and heat conducting functions according to claim 4, characterized in that: The molar ratio of graphene oxide to propylene glycol is 1:(1.0-1.2); the ultrasonic conditions are: ultrasonic frequency 40-60 Hz, ultrasonic time 30-45 min.

7. The method for preparing reconstituted tobacco leaves having both hygroscopicity regulating and heat conducting functions according to claim 1, characterized in that: In step (3), the gap between the blade and the roller is 1.2 mm, and the baking conditions are: temperature is 90° C., and baking time is 15 to 20 min.

8. A reconstituted tobacco leaf having both hygroscopicity regulating and heat conducting functions, characterized in that: It is prepared according to the preparation method according to claims 1-7.

9. Use of the reconstituted tobacco leaves having both hygroscopicity regulating and heat conducting functions according to claim 8 in heated cigarettes.

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