Conjugated heat-conducting modified cellulose thermal adhesive and its use in preparing heated cigarettes

Abstract

The present invention belongs to the technical field of tobacco materials, specifically relating to a conjugated heat-conducting modified cellulose thermal adhesive. It further discloses the use of the thermal adhesive in preparing thermally conductive enhanced tobacco sheets, shredded tobacco, or heated cigarettes. The conjugated heat-conducting modified cellulose thermal adhesive of the present invention incorporates soluble and edible cellulose and an oxidized conjugated thermally conductive material through a blending and granulation process for an esterification reaction. This achieves covalent bond fixation of the conjugated thermally conductive material, and utilizes the high thermal conductivity of the conjugated thermally conductive material to form a functional cellulose material with high thermal conductivity efficiency, which can be used to improve the thermal conductivity of tobacco and its tobacco products.

Description

Technical Field

[0001] The present invention belongs to the technical field of tobacco materials, and specifically relates to a conjugated heat-conducting modified cellulose thermal adhesive. The invention further discloses the use of the thermal adhesive in preparing thermally conductive enhanced tobacco sheets, tobacco shreds or heated cigarettes. Background Art

[0002] Tobacco flakes, also known as reconstituted tobacco, restructured tobacco, or homogenized tobacco, are primarily made from tobacco scraps, stems, or low-grade tobacco leaves, along with plant fibers, adhesives, and other additives. Made from low-grade tobacco, tobacco flakes not only reduce the tar content in smoke but also offer low cost and excellent filling properties. They are widely used as a raw material in cigarettes.

[0003] Heated cigarettes, also known as heat-not-burn cigarettes, are a new type of tobacco product compared to traditional tobacco products. They possess the characteristics of new tobacco products: they do not require combustion, do not produce secondhand smoke, and contain tobacco ingredients. They can adapt to and meet consumers' physiological needs to a certain extent while significantly reducing the harmful components such as tar produced by combustion, as well as the impact of secondhand smoke on the public environment and the health of others. Because heated cigarettes only heat their tobacco materials (250-350°C) without burning them, they require higher thermal conductivity from the tobacco segments than traditional tobacco products. This field is dedicated to developing cigarette materials suitable for the application of heated cigarettes.

[0004] As a new material with excellent thermal conductivity, graphene can now be mass-produced at a relatively low cost. However, due to food safety concerns and processing and molding issues, this material has not been widely adopted in areas such as food packaging and tobacco products. The field is eager to explore the application of graphene-based materials in tobacco products, particularly heated tobacco products, to improve their performance and user experience. Summary of the Invention

[0005] To this end, the technical problem to be solved by the present invention is to provide a conjugated heat-conducting modified cellulose thermal adhesive. The thermal adhesive utilizes the high thermal conductivity of the conjugated thermal conductive material and forms a functional cellulose material with high thermal conductivity efficiency through esterification and attachment to water-soluble cellulose, which can effectively improve the thermal conductivity of heated cigarette products.

[0006] The second technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned conjugated heat-conducting modified cellulose thermal adhesive;

[0007] The third technical problem to be solved by the present invention is to provide a tobacco sheet with enhanced thermal conductivity, wherein the tobacco sheet uses the thermal conductive adhesive to form an enhanced thermal conductive film, which can effectively improve the thermal conductivity of the tobacco sheet;

[0008] The fourth technical problem to be solved by the present invention is to provide a tobacco cut with enhanced heat conductivity;

[0009] The fifth technical problem to be solved by the present invention is to provide a heat-conductivity-enhanced heated cigarette product.

[0010] To solve the above technical problems, the present invention provides a method for preparing a conjugated heat-conducting modified cellulose thermally conductive adhesive, comprising the following steps:

[0011] (1) mixing a conjugated thermal conductive material with soluble cellulose, and performing blending and granulation to obtain esterified modified cellulose;

[0012] (2) adding the modified cellulose after the reaction into a solvent, mixing, and concentrating the mixture to obtain the product.

[0013] Specifically, in step (1):

[0014] The conjugated thermal conductive material includes an oxidized conjugated thermal conductive material;

[0015] Preferably, the conjugated thermal conductive material comprises one or a mixture of graphene oxide, carbon nanotube oxide or graphyne oxide;

[0016] The soluble cellulose includes one or a mixture of carboxymethyl cellulose, water-soluble cellulose ether, hydroxyethyl cellulose or hydroxypropyl cellulose;

[0017] Preferably, in step (1), the mass ratio of the conjugated thermal conductive material to the soluble cellulose is 1:10-200.

[0018] Specifically, in step (1), the blending and granulation step is twin-screw granulation;

[0019] Preferably, the process parameters of the blending and granulation step include: controlling the granulation temperature at 100° C.-200° C., preferably 110-190° C., and the screw aspect ratio at 40:1-60:1.

[0020] It should be noted that the esterification process of the conjugated thermal conductive material and the cellulose is completed simultaneously in the blending and granulation step, so the esterification reaction process is completed by controlling the granulation temperature at 100-200°C.

[0021] Specifically, in the step (2), the mass ratio of the modified cellulose to the solvent is 1:50-500;

[0022] Preferably, the solvent comprises a tobacco solvent;

[0023] Preferably, the solvent comprises water, ethylene glycol or glycerol, or a mixture of these.

[0024] Specifically, in the step (2), the viscosity of the glue is controlled to be 100-60000 cps in the concentration step;

[0025] Preferably, the step (2) further comprises the step of removing the unreacted conjugated thermally conductive material by solid-liquid separation.

[0026] As an practicable manner, the present invention further discloses a step of preparing the graphene oxide based on oxidation of graphite and / or graphene;

[0027] Preferably, the preparation steps of the graphene oxide include: taking graphite powder, adding concentrated sulfuric acid, mixing, and adding a strong oxidant to carry out an oxidation reaction; then adding deionized water to continue the reaction, and adding H2O2 until no bubbles are generated in the solution; collecting the reactants, washing and drying to obtain the graphene oxide.

[0028] As an practicable method, the preparation steps of the graphene oxide include: adding graphite powder to concentrated sulfuric acid, stirring thoroughly in an ice-water bath, then slowly adding a certain amount of KMnO4, controlling the reaction at a low water bath temperature; heating to a certain temperature, and continuing to stir for 30 minutes; then slowly adding deionized water to the reaction solution, and controlling the solution temperature to about 60-120°C to react for 15 minutes, and then adding a certain amount of 5% H2O2 to the solution until no bubbles are generated in the solution; filtering while hot, and thoroughly washing the filter cake with 5% HCl and deionized water until the filtrate is neutral; and drying the filter cake for 48 hours to obtain graphite oxide samples with different degrees of oxidation.

[0029] The invention also discloses conjugated heat-conducting modified cellulose thermal conductive adhesive prepared by the method.

[0030] The present invention also discloses the conjugated heat transfer modified cellulose thermal conductive adhesive, or the use of the conjugated heat transfer modified cellulose thermal conductive adhesive prepared by the method in preparing thermally conductive enhanced tobacco sheets, tobacco shreds or heated cigarette products.

[0031] The present invention also discloses a heat-conductivity-enhanced tobacco sheet, comprising a tobacco sheet and a heat-conducting film formed on at least one surface of the tobacco sheet;

[0032] The thermally conductive film is formed by spraying and curing the oxide conjugate heat transfer modified thermally conductive adhesive;

[0033] Preferably, the mass ratio of the thermally conductive adhesive to the tobacco sheet is 1:50-1000.

[0034] The present invention also discloses a heat-conductivity-enhanced cut tobacco, which is formed by cutting the heat-conductivity-enhanced tobacco sheet, or by spraying and curing the conjugate heat-conducting modified cellulose heat-conducting adhesive on the surface of the cut tobacco.

[0035] The present invention also discloses a heat-conductivity-enhanced heated cigarette, comprising the heat-conductivity-enhanced cut tobacco. The heat-conductivity-enhanced cut tobacco is selected as the heat-conductivity-enhanced cut tobacco and is processed using conventional processes.

[0036] The present invention also discloses the application of the conjugated heat-conducting modified cellulose thermal conductive adhesive, thermally conductive enhanced tobacco sheet, tobacco shreds or heated cigarettes in the field of tobacco processing.

[0037] The conjugated heat-conducting modified cellulose thermal conductive adhesive of the present invention achieves covalent bond fixation of conjugated thermal conductive materials, especially oxidized conjugated thermal conductive materials, by introducing soluble and edible cellulose and conjugated thermal conductive materials in a blended granulation manner. This can effectively block the risk of thermal conductive materials migrating into the human body during tobacco smoking, and effectively solves the bottleneck problem that thermal conductive materials such as graphene oxide cannot be used in tobacco products due to processing and molding problems.

[0038] The conjugated heat-conducting modified cellulose thermal conductive adhesive of the present invention utilizes the high thermal conductivity of conjugated thermal conductive materials such as graphene oxide, and can form a functional cellulose material with high thermal conductivity efficiency through esterification and attachment on water-soluble cellulose, which can be used to improve the thermal conductivity of tobacco and its cigarette products.

[0039] The conjugated heat transfer modified cellulose thermal conductive adhesive described in the present invention is formed by dissolving conjugated thermal conductive materials such as graphene oxide and cellulose in water to form a colloidal material. The material has good adhesion to carriers such as tobacco sheets, can be dissolved and sprayed on tobacco sheets, and is easy to dry. It can be easily used to modify the thermal conductivity of tobacco products, completely solving the application barriers of thermal conductive materials such as graphene in the food and tobacco fields.

[0040] The thermally conductive enhanced tobacco sheets and tobacco shreds described in the present invention can improve their thermal conductivity by spraying and curing the conjugated heat-conducting modified cellulose thermal conductive adhesive on the surface, ultimately forming a layer of functional cellulose thermal conductive film with high thermal conductivity on the surface of the tobacco sheet, effectively improving the thermal conductivity of the cigarette products, especially heated cigarette products, thereby improving the application performance and application experience of the heated cigarette products. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0042] Figure 1IR spectra of graphene oxide (OGO), cellulose (Cellulose), and esterified graphene cellulose (Cellulose-OGO) in Example 2;

[0043] Figure 2 DSC and TGA curves of the thermal conductive adhesive sample in Example 2 of the present invention;

[0044] Figure 3 These are electron microscope images of the heat-conducting tobacco samples in Application Examples 1, 2, and 4 of the present invention. DETAILED DESCRIPTION

[0045] Preparation Example

[0046] Add 5 grams of graphite powder to 50 mL of concentrated sulfuric acid, stir thoroughly in an ice-water bath, then slowly add a certain amount of KMnO4, and control the water bath temperature at 10-15°C for oxidation reaction; heat to room temperature and continue stirring for 30 minutes; then slowly add 100 mL of deionized water to the reaction solution, and control the solution temperature at around 80°C to continue the reaction for 15 minutes, then add 30 grams of 5% H2O2 to the solution until no bubbles are generated in the solution; collect the reactants and filter them while hot, and wash the filter cake thoroughly with 5% HCl and deionized water until the filtrate is neutral; dry the filter cake for 48 hours to obtain 4.6 grams of graphene oxide sample.

[0047] Examples 1-5

[0048] A certain amount of the aforementioned graphene oxide sample was mixed with a corresponding amount of carboxymethyl cellulose. The mixture was then blended and granulated in a twin-screw extruder (with a screw aspect ratio of 50:1). The esterification reaction was simultaneously completed during granulation to produce esterified graphene-modified cellulose. In each embodiment, the temperature of the granulation step (i.e., the esterification temperature) was controlled between 110°C and 190°C to regulate the esterification reaction between the graphene oxide and the cellulose.

[0049] The specific addition ratios of each embodiment and the temperature (110° C.-190° C.) for controlling the esterification process are detailed in Table 1 below.

[0050] The graphene-modified cellulose material obtained after the reaction was dissolved in a certain amount of water, and the unreacted graphene oxide material was removed by centrifugation. The amount of water used in each embodiment is shown in Table 1 below. The mass ratio of the graphene-modified cellulose to water is 1:50-500.

[0051] The liquid portion after centrifugal removal of graphene oxide was collected and heated and concentrated to reach the viscosity required for spraying, forming a cellulose-reinforced thermal conductive adhesive product. The viscosity of the adhesive was controlled to be between 100 and 60,000 cps in the concentration step of each embodiment. Specific control parameters are detailed in Table 1 below.

[0052] Table 1 Preparation ratio of oxidation-enhanced thermal conductive adhesive

[0053] serial number Graphene oxide / g Fiber / g Esterification temperature / ℃ Centrifugal water consumption / kg Viscosity / cps Example 1 1 200 190 10 100 Example 2 1 100 170 10 1000 Example 3 1 50 150 10 5000 Example 4 1 25 130 10 20000 Example 5 1 10 110 5 60000

[0054] The three materials selected in Example 2, graphene oxide, cellulose, and graphene esterified fiber obtained by blending, granulation and esterification were subjected to infrared spectroscopy. The results are as follows: Figure 1 As shown. It can be seen that the expected esterification process occurred during the entire blending and granulation process, and after the esterification process, the carbonyl peak of graphene shifted from 1651 cm -1 Transfer to 1716cm -1 , proving that the carbonyl groups on graphene were converted from carboxylic acid carbonyl groups to ester carbonyl groups, and the modified graphene was successfully attached to cellulose through ester bonds.

[0055] The thermal conductivity of the thermally conductive adhesive prepared in Example 2 was tested. Figure 2 As shown. Figure 2 From the DSC curve, we can see that below 100°C, water vapor evaporates quickly, which is conducive to the rapid drying of the thermal adhesive. The glass transition temperature of the thermal adhesive is around 175°C, which ensures the mechanical stability of the thermal adhesive during the heat-not-burn cigarette smoking process. Figure 2 It can be seen from the TGA curve that its decomposition temperature is around 300°C, which ensures the safety of smoking the heat-not-burn tobacco.

[0056] Example 6

[0057] The raw material components and preparation method of the conjugated heat-conducting modified cellulose thermal adhesive described in this embodiment are the same as those in Example 2, with the only difference being that the soluble cellulose is water-soluble cellulose ether and the conjugated thermal conductive material is oxidized carbon nanotubes.

[0058] Example 7

[0059] The raw material components and preparation method of the conjugated heat-conducting modified cellulose thermally conductive adhesive described in this embodiment are the same as those in Example 2, with the only difference being that the soluble cellulose is hydroxyethyl cellulose and the conjugated thermally conductive material is Graphene Oxide.

[0060] Application Examples 1-4

[0061] The thermally conductive adhesive prepared in Example 2 was used to prepare enhanced thermally conductive tobacco. A certain amount of thermally conductive adhesive sample was weighed and added to an atomizing spray bottle. The valve was adjusted to dispense the adhesive in a mist with a viscosity of 1000 cps. The adhesive was evenly sprayed onto the surface of a certain amount of tobacco and allowed to dry naturally at room temperature for 2 hours to produce the corresponding enhanced thermally conductive tobacco product. The ratios of thermally conductive adhesive to tobacco used in each application example are shown in Table 2 below. Tobacco without the thermally conductive adhesive was used as a control.

[0062] Application Example 5

[0063] The preparation method of the tobacco in this application example is the same as that in the above-mentioned application example 4, and the composition ratio of the thermal conductive adhesive is the same as that in Example 2, the only difference being that the graphene oxide is replaced by ordinary graphene.

[0064] Comparative Example 1

[0065] The material composition and preparation method of the tobacco described in this comparative example are the same as those of the above-mentioned Application Example 4, and the component ratio of the thermal conductive adhesive is the same as that of Example 2. The only difference is that the thermal conductive adhesive does not undergo a twin-screw granulation esterification process, and only the same amount of graphene oxide as in Example 2 is selected to be dissolved in water to form an adhesive solution with the same viscosity, which is then directly sprayed on the surface of the tobacco.

[0066] The thermal conductivity of the enhanced heat-conductive tobacco prepared in the above-mentioned Application Examples 1-5 and Comparative Example 1 was tested respectively. The test results are shown in Table 2.

[0067] Table 2 Preparation of enhanced thermal conductivity tobacco and thermal conductivity results

[0068] serial number Tobacco dosage / g Thermal adhesive dosage / g <![CDATA[Thermal conductivity / Wm -1 K -1 > Application Example 1 100 0 0.135 Application Example 2 100 0.1 0.502 Application Example 3 100 1 1.397 Application Example 4 100 2 1.406 Application Example 5 100 2 0.403 Comparative Example 1 100 2 0.392

[0069] The microstructure (electron microscope) of the enhanced heat-conducting tobacco prepared in the above application examples 1, 2 and 4 was measured respectively, and the electron microscope pictures are as follows: Figure 3 As shown in (a) to (c) of FIG. 1 , it can be seen from the microstructure diagram that the addition of the thermally conductive adhesive prepared by the present invention does not change the surface structure of the tobacco, and is suitable for the processing of tobacco and cigarette products.

[0070] From the above results, it can be seen that the thermal conductive adhesive of the present invention can effectively improve the thermal conductivity of tobacco without changing the surface structure of tobacco, and can effectively improve the application performance and application experience of heated cigarettes.

[0071] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A conjugated heat transfer modified cellulose thermal adhesive for use in preparing thermally conductive enhanced tobacco sheets, tobacco shreds or heated cigarette products, characterized in that: The preparation method of the conjugated heat-conducting modified cellulose thermally conductive adhesive comprises the following steps: (1) Mixing a conjugated thermal conductive material with soluble cellulose, and performing blending and granulation to obtain esterified modified cellulose; (2) adding the modified cellulose after the reaction to a solvent, mixing, and concentrating the mixture to obtain the conjugated thermal conductive material, which is an oxidized conjugated thermal conductive material; The conjugated thermal conductive material includes one or a mixture of graphene oxide, carbon nanotube oxide or graphyne oxide; In the step (1), the mass ratio of the conjugated thermal conductive material to the soluble cellulose is 1:10-200.

2. The use according to claim 1, characterized in that In step (1): The soluble cellulose includes water-soluble cellulose ether.

3. The use according to claim 1, characterized in that In the step (1), the soluble cellulose includes one or a mixture of carboxymethyl cellulose, hydroxyethyl cellulose or hydroxypropyl cellulose.

4. The use according to claim 3, characterized in that In the step (1), the blending and granulation step is twin-screw granulation.

5. The use according to claim 4, characterized in that The process parameters of the blending and granulation step include: controlling the granulation temperature to be 100° C.-200° C. and the screw aspect ratio to be 40:1-60:

1.

6. The use according to any one of claims 1 to 5, characterized in that In the step (2), the mass ratio of the modified cellulose to the solvent is 1:50-500.

7. The use according to claim 6, characterized in that The solvent includes one or a mixture of water, ethylene glycol or glycerol.

8. The use according to claim 7, characterized in that In the step (2), the concentration step controls the viscosity of the glue to be 100-60000 cps.

9. The use according to claim 8, characterized in that The step (2) further includes a step of removing the unreacted conjugated thermal conductive material by solid-liquid separation.

10. A tobacco sheet with enhanced thermal conductivity, characterized in that: The invention comprises a tobacco sheet and a heat-conductive film formed on at least one surface of the tobacco sheet; The thermally conductive film is formed by spraying and curing the conjugated heat-conducting modified cellulose thermally conductive adhesive described in any one of claims 1 to 9.

11. The tobacco sheet according to claim 10, wherein The mass ratio of the thermal conductive adhesive to the tobacco sheet is 1:50-1000.

12. A heat-conductivity enhanced tobacco, characterized in that: The tobacco shreds are formed by cutting the heat-conducting enhanced tobacco sheet according to claim 11, or by spraying and curing the conjugated heat-conducting modified cellulose thermal conductive adhesive described in any one of claims 1 to 9 on the surface of the tobacco shreds.

13. A heat-conductivity enhanced heated cigarette, characterized in that: Including the heat-conductivity enhanced tobacco according to claim 12.

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