A heating cigarette reconstituted tobacco low-temperature flavor-releasing heat-conducting adhesive and a preparation method thereof
By using a mixed colloid of modified titanium silicon molecular sieve and modified metal oxide powder in reconstituted tobacco leaves for heated cigarettes, the problems of uneven material distribution and interface mismatch in reconstituted tobacco leaves were solved, achieving a synergistic effect of low-temperature catalysis and thermal conduction, thereby improving the aroma release efficiency and taste consistency of heated cigarettes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA TOBACCO SHANDONG IND
- Filing Date
- 2026-06-04
- Publication Date
- 2026-07-24
AI Technical Summary
In existing technologies, titanium-silicon molecular sieves and thermally conductive fillers have problems such as interface mismatch, easy precipitation and difficulty in mixing in reconstituted tobacco leaves, resulting in uneven aroma release and inconsistent taste in heated cigarettes, and difficulty in effective catalysis and heat conduction at low temperatures.
Organometallic salt-modified titanium-silicon molecular sieves and silane coupling agent-modified metal oxide powders are used as low-temperature catalytic materials and thermally conductive fillers. They are mixed in a matrix colloid by vacuum stirring to form a low-temperature aroma-releasing thermally conductive adhesive for heated cigarette reconstituted tobacco leaves. This ensures that the materials are evenly distributed in the reconstituted tobacco leaves and improves the thermal conductivity.
The low-temperature catalytic material and thermally conductive filler were stably and uniformly distributed in reconstituted tobacco leaves, which improved the aroma release efficiency and thermal conductivity, ensuring the consistency of taste and uniformity of aroma in heated cigarettes, and meeting the requirements of safety and industrial production.
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Figure CN122439900A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of tobacco manufacturing technology, specifically relating to a low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves used in heated cigarettes and its preparation method. Background Technology
[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.
[0003] One of the core technologies of heated cigarettes is producing smoke containing nicotine and tobacco flavor compounds at a relatively low temperature. Currently, the heating temperature of heated cigarettes is typically around 350℃, far lower than the 800℃ heating temperature of traditional cigarettes. This results in a lower content of flavor compounds in heated cigarettes, manifesting as a milder flavor. Titanium silicate molecular sieves, with their unique microporous structure and high specific surface area, possess catalytic effects, reducing the activation energy required for the decomposition of tobacco flavor compounds. Furthermore, the introduction of metal ions or oxides further enhances their low-temperature aroma release performance. Adding thermally conductive fillers to improve the overall thermal conductivity of reconstituted tobacco leaves can also improve the taste of heated cigarettes.
[0004] Because low-temperature aroma-releasing materials and thermally conductive fillers have high densities, they are prone to sedimentation during the preparation of reconstituted tobacco. Mixing them with colloids to prepare an aroma-releasing and thermally conductive adhesive can solve the problem of filler sedimentation caused by density differences during reconstituted tobacco preparation. Currently, while modifying titanium-silicon molecular sieves and thermally conductive fillers separately and introducing them into the matrix colloidal system can achieve corresponding functions in a single system, both methods have some drawbacks. For example, when only titanium-silicon molecular sieve aroma-releasing materials are present in reconstituted tobacco, the tobacco in contact with the aroma-releasing material releases smoke rapidly, while the tobacco further away releases aroma slowly, resulting in inconsistent smoke flavor. Similarly, when only thermally conductive fillers are present in reconstituted tobacco, although this solves some of the smoke flavor issues, it does not lower the aroma-releasing temperature of the reconstituted tobacco. Furthermore, when both types of fillers coexist, differences in their surface properties, particle size distribution, and interfacial interaction mechanisms can easily lead to interfacial mismatch. Specifically, titanium-silicon molecular sieves exhibit strong polarity, while thermally conductive fillers modified with silane coupling agents typically demonstrate organic affinity. These differences compete for interfacial active sites within the matrix, disrupting the interfacial layer structure and reducing the system's dispersion stability. On the other hand, the differences in particle size and specific surface area between the two types of fillers increase the difficulty of mixing, leading to heterogeneous agglomeration and localized enrichment during the mixing process, affecting the material's structural uniformity. Therefore, current technology lacks a solution that can achieve low-temperature aroma release, enhanced thermal conductivity, and improved taste in reconstituted tobacco while simultaneously maintaining structural stability and multifunctional performance. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the present invention aims to provide a low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves and its preparation method. This invention achieves long-term stable and uniform distribution of low-temperature catalytic materials and thermally conductive fillers in reconstituted tobacco leaves, ensuring their consistency and reliability in actual use.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, a low-temperature aroma-releasing thermally conductive adhesive for heated cigarette reconstituted tobacco leaves comprises the following components in parts by weight: 2-6 parts of low-temperature catalytic material, 0.8-1.2 parts of thermally conductive filler, and 100 parts of matrix colloid; wherein the low-temperature catalytic material is a titanium-silicon molecular sieve modified with an organometallic salt, and the thermally conductive filler is a metal oxide powder modified with a silane coupling agent.
[0007] Secondly, the preparation method of the above-mentioned low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves for heated cigarettes includes the following steps: adding low-temperature catalytic materials and thermally conductive fillers into the matrix colloid, and stirring under vacuum at 40~60℃ for 1~1.5h to obtain the low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves for heated cigarettes.
[0008] Thirdly, the application of the aforementioned low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves in the preparation of reconstituted tobacco leaves includes: After mixing tobacco powder, CMC and glycerol, the low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves is added, and the mixture is then coated to prepare reconstituted tobacco leaves.
[0009] The beneficial effects of this invention are as follows: 1. This invention disperses low-temperature catalytic materials and thermally conductive fillers together in a matrix colloid to form a thermally conductive adhesive. This avoids the problem of functional component sedimentation caused by density differences, achieving a long-term stable and uniform distribution of the low-temperature catalytic materials and thermally conductive fillers in reconstituted tobacco leaves, ensuring density consistency and reliability for continuous use. The low-temperature catalytic materials can effectively catalyze the decomposition of tobacco aroma precursors within a lower temperature range, significantly reducing the activation energy for aroma release, thereby improving aroma release efficiency and solving the problems of insufficient aroma release and bland taste in traditional reconstituted tobacco leaves. Using metal oxides modified with silane coupling agents as thermally conductive fillers improves the overall thermal conductivity of reconstituted tobacco leaves while effectively reducing the interfacial thermal resistance between the thermally conductive filler and the tobacco matrix, making heat transfer more efficient and uniform, and enhancing the stability of smoke release.
[0010] 2. The raw materials used in this invention are widely available and inexpensive, and the preparation process is simple, making it easy to promote and use industrially. Furthermore, the resulting thermally conductive adhesive exhibits good thermal stability, is non-toxic and odorless, and will not decompose or release harmful components within its operating temperature range, meeting the material safety requirements for heated cigarettes. Therefore, this invention can effectively enhance the flavor release of tobacco leaves and improve the user's smoking experience without increasing the heating temperature, demonstrating good practicality, innovation, and promotional value. Attached Figure Description
[0011] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0012] Figure 1 Thermogravimetric analysis (TGA) of the reconstituted tobacco prepared in Example 1.
[0013] Figure 2 Thermogravimetric analysis (TGA) of the reconstituted tobacco prepared in Example 2.
[0014] Figure 3 This is an electron microscope image of the reconstituted tobacco leaf prepared in Example 1.
[0015] Figure 4 This is an electron microscope image of the reconstituted tobacco leaf prepared in Comparative Example 4. Detailed Implementation
[0016] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0017] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0018] One or more embodiments of the present invention provide a low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves for heated cigarettes, comprising the following components in parts by weight: 2-6 parts of low-temperature catalytic material, 0.8-1.2 parts of thermally conductive filler, and 100 parts of matrix colloid; wherein the low-temperature catalytic material is an organometallic salt modified titanium-silicon molecular sieve, and the thermally conductive filler is a silane coupling agent modified metal oxide powder.
[0019] Among the above components, the metal components in the low-temperature catalytic material can promote the low-temperature oxidation of volatile organic compounds. Titanium silicate molecular sieves, with their unique microporous structure and high specific surface area, can firmly adsorb and fix the metal components, increase the effective contact area between the metal components and reconstituted tobacco leaves, and reduce the proportion of metal components used, playing an important role in the low-temperature aroma release reaction. Metal oxides have high melting points and good thermal conductivity, and are usually used as thermally conductive fillers. However, their density is high, and the thermal resistance between the thermally conductive filler and the reconstituted tobacco leaves is large, which reduces the thermal conductivity of the reconstituted tobacco leaves. Surface modification of the thermally conductive filler can reduce its thermal resistance and improve the thermal conductivity of the reconstituted tobacco leaves.
[0020] Optionally, the particle size of the thermally conductive filler is 50-80 μm, and the particle size of the molecular sieve is 70-100 μm. Too small a particle size increases the interfacial thermal resistance at the contact surface between the thermally conductive filler / molecular sieve and the reconstituted tobacco leaf, and poses a risk of these particles entering the body with the smoke. A particle size of 50 μm or larger typically ensures that the thermally conductive filler cannot pass through the filter and enter the body. Too large a particle size makes the thermally conductive filler prone to sedimentation, and larger particles reduce the overall tensile mechanical properties of the reconstituted tobacco leaf. Since the density of the thermally conductive filler is greater than that of the molecular sieve, a particle size of 50-80 μm is preferred for the thermally conductive filler, while a corresponding particle size of 70-100 μm can be selected for the molecular sieve.
[0021] One or more embodiments of the present invention provide a method for preparing the above-mentioned low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves of heated cigarettes, comprising the following steps: adding low-temperature catalytic materials and thermally conductive fillers to a matrix colloid, and stirring under vacuum at 40~60℃ for 1~1.5h to obtain the low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves of heated cigarettes.
[0022] In the above process, vacuum stirring can improve mixing efficiency and prevent bubble formation, resulting in a uniform thermally conductive adhesive with suitable fluidity, thus avoiding bubbles from affecting the density and thermal conductivity of the adhesive.
[0023] Optionally, the preparation method of the low-temperature catalytic material includes: adding tetraethyl orthosilicate and tetrabutyl titanate in a mass ratio of (1~3):(1~2) to a tetrapropylammonium hydroxide solution, synthesizing a gel at 70~90℃, crystallizing at 160℃~180℃ for 24~48 h, cooling and drying, and then calcining at 600℃~800℃ for 8~10 h to obtain a titanium-silicon molecular sieve; adding the titanium-silicon molecular sieve to a metal-organic salt solution with a concentration of 0.03~0.07mol / L, stirring, filtering the solid, evaporating and drying, and then calcining at 600~800℃ for 12~14 h to obtain the low-temperature catalytic material. In this invention, the precise regulation of the pore structure and catalytic activity of the titanium-silicon molecular sieve is achieved through the synergistic control of the synthesis and post-processing parameters. A precursor gel is formed at 70–90 °C. This temperature range is beneficial for controlling the hydrolysis and condensation rate of silicon-titanium species, ensuring uniform dispersion of titanium species in the silicon source system and reducing the formation of non-framework titanium. Subsequently, crystallization is carried out at 160–180 °C for 24–48 h. By controlling the crystallization temperature and time, the grain size and framework order of the molecular sieve can be adjusted. During the crystallization process of titanium-silicon molecular sieves, the crystallization temperature and time affect the pore structure by regulating the crystal nucleation process. When the crystallization temperature is low or the crystallization time is short, the nucleation rate is fast but the crystal growth is insufficient, easily forming molecular sieves with small grain sizes and many structural defects. These defects (such as grain boundaries, incomplete condensation sites, etc.) introduce additional pore space outside the microporous framework, resulting in an increase in effective pore size or the appearance of secondary pores (micro-mesoporous synergistic structure), while enhancing pore connectivity. However, excessively low temperatures or short times may lead to an incomplete framework and decreased pore regularity. Conversely, when the crystallization temperature is higher or the crystallization time is longer, crystal growth is more complete, the framework structure tends to be more complete and ordered, the number of defects decreases, and the molecular sieve channels become more regular and uniform. This is manifested as a more concentrated pore size distribution and a more stable microporous structure, but the secondary pore structure decreases, and the overall pore structure tends to be a "single microporous system," with a slight reduction in pore size expansion or connectivity. If the conditions are too strong, it may also lead to grain growth and pore mouth shrinkage, thereby reducing the accessibility of the outer surface to some extent. Therefore, by adjusting the crystallization temperature (e.g., 160~180℃) and crystallization time (24~48 h) within a certain range, a balance can be achieved between "structural regularity" and "defect-induced expanded pore structure," so that the material retains the characteristic micropores of molecular sieves while introducing an appropriate amount of secondary pores, thereby achieving an adjustable effective pore size and higher pore accessibility that is different from existing single microporous materials. The low-temperature catalytic material prepared by the above process is characterized by molecular sieve particles with a narrow grain size distribution. They are uniformly dispersed and some exhibit slight defects or rough surface structures, which is conducive to the formation of a high proportion of external surface active sites. In addition to retaining the typical microporous characteristics of molecular sieves, its pore structure also forms secondary pores or micro-mesoporous synergistic structures induced by defects, making the overall pore connectivity better than that of traditional single microporous materials.Compared with the prior art, the material obtained by the present invention has a higher proportion of framework titanium embedded in the silicon framework in a four-coordinated manner, the content of non-framework titanium is reduced, and the active metal species are more uniformly distributed and mainly located in easily accessible surface or pore areas, thereby significantly reducing diffusion restriction and achieving higher catalytic activity and stability at lower temperature conditions.
[0024] Optionally, the concentration of the tetrapropylammonium hydroxide (TPAOH) solution is 20%~30%, preferably 25%, and the mass ratio of tetraethyl orthosilicate (TEOS), tetrabutyl titanate and tetrapropylammonium hydroxide is (1~3):(1~2):(2~8). Within the above ratio range, since the amounts of TEOS and tetrabutyl titanate are similar, the Ti content in the system is relatively high. During the crystallization process, titanium species participate in the framework construction and have a disturbing effect on crystal growth, which reduces the crystal growth rate and makes the growth of each crystal face tend to be uneven, thus making it easier to form a particle morphology with smaller grain size and more uniform distribution. At the same time, the high Ti content will also introduce structural defects to a certain extent, making the crystal surface slightly rough or irregular in shape, which is beneficial to increasing the external specific surface area. Furthermore, TPAOH provides moderate alkalinity and template effect within the above dosage range; under these conditions, on the one hand, it can promote the uniform generation of crystal nuclei and inhibit excessive growth, so that the resulting molecular sieves mostly exhibit nano / submicron-sized particles that are approximately spherical or short rod-shaped; on the other hand, a moderate concentration of template agent is conducive to the formation of a well-structured framework, while avoiding excessive crystal growth into regular large crystal blocks.
[0025] Optionally, the organometallic salt includes one or more of copper acetate, ammonium molybdate, and phosphotungstic acid.
[0026] Optionally, the preparation method of the thermally conductive filler includes: adding metal oxide powder to a silane coupling agent solution, stirring and reacting to obtain modified metal oxide powder, and ball milling the modified metal oxide powder to obtain the thermally conductive filler. Metal oxides have high melting points and good thermal conductivity, and are commonly used as thermally conductive fillers. However, their density is high, and the thermal resistance between the thermally conductive filler and reconstituted tobacco is relatively large, reducing the thermal conductivity of the reconstituted tobacco. Surface modification of the thermally conductive filler can reduce its thermal resistance and improve the thermal conductivity of the reconstituted tobacco. Through the mechanical shearing and impact during ball milling, the filler particles can be broken and refined, preventing the thermally conductive filler from sticking and agglomerating due to the modifier. Although limited refining can also be achieved through ultrasonic vibration and other means, in this invention where it needs to work in conjunction with molecular sieves, ball milling is necessary to ensure a more uniform dispersion of the filler.
[0027] Optionally, the metal oxide powder includes one or more of aluminum oxide, magnesium oxide, and zinc oxide, with a particle size of 50-80 μm.
[0028] Optionally, the silane coupling agent includes triethoxysilane, and the concentration of the silane coupling agent solution is 3~7 mg / mL; the silane coupling agent can promote the dispersion of thermally conductive fillers in the matrix colloid and prevent agglomeration that causes local overheating of reconstituted tobacco leaves.
[0029] Optionally, the solvent for the silane coupling agent is ethanol.
[0030] Optionally, after stirring for 1-2 hours, let stand for 1-2 hours, wash with ethanol, and then dry to obtain the modified metal oxide powder.
[0031] Optionally, during ball milling, the modified metal oxide powder and stainless steel balls are added to anhydrous ethanol at a mass ratio of 1:(5~6), and ball milled at a speed of 300~500 r / min for 6~12 h, then cleaned and dried.
[0032] One or more embodiments of the present invention provide the application of the above-mentioned low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves in the preparation of reconstituted tobacco leaves, including: After mixing tobacco powder, CMC and glycerol, the low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves is added, and the mixture is then used to prepare reconstituted tobacco leaves.
[0033] The low-temperature aroma-releasing thermal conductive adhesive for heated cigarette reconstituted tobacco leaves can reduce the aroma release temperature of reconstituted tobacco leaves, increase the thermal conductivity of reconstituted tobacco leaves, and thus improve the smoking taste of reconstituted tobacco leaves.
[0034] Optionally, the mass ratio of tobacco powder, CMC, glycerol, and the low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves in heated cigarettes is 100:(1~2):(30~40):(1~2). Tobacco powder is the main source of aroma in reconstituted tobacco smoke; if its proportion is too low, it will reduce the usage time of the cigarette. CMC is responsible for increasing the viscosity of the reconstituted tobacco matrix and preventing the reconstituted tobacco from cracking. If it is too low, the overall viscosity of the reconstituted tobacco will be insufficient, and the physical strength will decrease. If it is too high, it will be detrimental to the slitting and processing of the reconstituted tobacco. Glycerol is the atomizing agent for reconstituted tobacco. When the amount of glycerol added is too low, its moisturizing and plasticizing effects are insufficient, resulting in unstable overall moisture content of the system. This leads to increased brittleness and decreased flexibility of the tobacco leaves, and the smoke is prone to exhibiting undesirable sensory characteristics such as dryness and increased irritation during smoking. When the amount of glycerol added is too high, it may cause the smoke to feel too moist, the combustion to be unstable, or the draw resistance to change abnormally. It may also interfere with the aroma release rhythm and reduce the overall sensory balance. If the amount of thermally conductive adhesive is too low, it will reduce the effect of low-temperature aroma release and heat conduction of reconstituted tobacco leaves. If it is too high, it will cause the smoke components of reconstituted tobacco leaves to be released too quickly and increase the irritation of the taste.
[0035] Optionally, the tobacco powder is 200-400 mesh. When the tobacco powder particle size is too large, the contact points between particles decrease, and the specific surface area per unit volume is low. This results in insufficient coating and bridging effect of cellulose colloids or binders on the tobacco powder, thus forming a loose, unevenly porous sheet-like system. During combustion, due to the uneven pore distribution, local combustion instability and large fluctuations in combustion rate are likely to occur. When the tobacco powder particle size is too small (overly fine), the system is more likely to form a dense agglomerate structure during the forming process, leading to reduced porosity and decreased air permeability. This may cause excessive densification of the sheet material, resulting in poor combustion permeability and increased tendency for incomplete combustion or smoldering.
[0036] The present invention will be further described below with reference to the embodiments.
[0037] Example 1 A low-temperature aroma-releasing thermally conductive adhesive for heated cigarette reconstituted tobacco leaves, the preparation method of which includes: S1. A 25% tetrapropylammonium hydroxide (TPAOH) solution was prepared by mixing tetraethyl orthosilicate (TEOS), tetrabutyl titanate, and tetrapropylammonium hydroxide in a mass ratio of 2:1:7. The mixture was stirred at 80°C for 2 hours to form a homogeneous gel. The resulting gel was transferred to a sealed reaction vessel and crystallized at 170°C for 36 hours. After the reaction was completed, the mixture was cooled to room temperature and filtered to obtain a solid product. The solid product was washed with deionized water until neutral, then dried at 120°C for 12 hours, and finally calcined at 700°C in air for 8 hours to obtain white titanium dioxide. The titanium-silicon molecular sieve powder was added to a 0.05 mol / L ammonium molybdate solution at a solid-liquid ratio of 5 g: 100 mL. The mixture was stirred at 25 °C for 12 h, allowed to settle, and the supernatant was removed. The mixture was then filtered to obtain a wet filter cake. The wet filter cake was slowly evaporated to dryness at 120 °C and then calcined at 700 °C under N2 conditions for 12 h to obtain a gray modified titanium-silicon molecular sieve, which is a low-temperature catalytic material. The titanium-silicon molecular sieve prepared under the above conditions has an MFI-type microporous structure with a stable pore size in the range of about 0.5~0.6 nm. The crystals are distributed at the submicron level with an average particle size of about 60~80 μm. The overall shape is short rod-shaped or irregular particles with a high external specific surface area and good dispersibility.
[0038] S2. Prepare a silane coupling agent solution by adding triethoxysilane to anhydrous ethanol at a mass / volume ratio of 0.5g:100mL. Take alumina powder with a particle size of 50μm and add it to the obtained silane coupling agent solution at a solid-liquid ratio of 10g:100mL. Stir for 1 hour and let stand for 1 hour. Wash three times with anhydrous ethanol and dry at 60℃ for 12 hours to obtain a dry modified powder. Mix the above modified powder with anhydrous ethanol at a solid-liquid ratio of 10g:100mL and add it to a ball mill along with stainless steel balls with a diameter of 6mm. The mass ratio of dry modified powder to stainless steel balls is 1:5. Ball mill at 400r / min for 8 hours. After the milling is completed, filter to remove the stainless steel balls, wash and dry at 120℃ for 12 hours to obtain a thermally conductive filler.
[0039] S3. Dissolve sodium carboxymethyl cellulose (CMC) in deionized water at a mass-volume ratio of 1g:100mL to form a uniform matrix colloid. Mix the low-temperature catalyst, thermally conductive filler and matrix colloid at a mass ratio of 4:1:10, and stir and degas at 40℃ for 1 hour to obtain a uniform thermally conductive adhesive with moderate flowability, which is the low-temperature aroma release thermally conductive adhesive for heated cigarette reconstituted tobacco leaves.
[0040] The application of the low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves in the preparation of reconstituted tobacco leaves in this embodiment includes: The tobacco leaves were crushed and passed through a 300-mesh sieve to obtain tobacco powder. 100g of tobacco powder was weighed and mixed evenly with 2g of CMC. Then, 40g of glycerol and 2g of the low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves obtained in this embodiment were added. The mixture was stirred with a stirring rod until it was uniformly moist and resembled putty. The mixture was then centrifuged in a high-speed vortex pulper at a speed of 3000 rpm for 5 minutes. The processed material was spread out in a 60°C mesh belt oven for drying. After reaching the outlet, the sheets were collected and sealed to obtain reconstituted tobacco leaves.
[0041] The electron scanning microscope image of the reconstituted tobacco leaf prepared in this embodiment is shown below. Figure 3 As shown in the figure, the reconstituted tobacco leaves have fine fibers and are evenly distributed. No large particles appear in the reconstituted tobacco leaves, and the overall quality of the tobacco leaves is uniform, indicating that the present invention has little impact on the overall structure of the reconstituted tobacco leaves.
[0042] Figure 1To obtain the pyrolysis diagram of the product in this embodiment, the reconstituted tobacco leaves showed a significant decrease in pyrolysis quality around 240℃, with a dramatic change in the heat flow curve, indicating that the reconstituted tobacco leaves underwent a chemical reaction and released aroma around this temperature. When the temperature reached 310℃, the pyrolysis curve became stable, indicating that the aroma release reaction almost stopped at this temperature. Compared to traditional reconstituted tobacco leaves, which stop reacting around 350℃, this invention can lower the reaction temperature of reconstituted tobacco leaves. That is, the reconstituted tobacco leaf sample releases aroma at 245℃~250℃, with uniform and long-lasting aroma release, no obvious thermal hysteresis, excellent thermal conductivity, and stable leaf structure.
[0043] Example 2 A low-temperature aroma-releasing thermally conductive adhesive for heated cigarette reconstituted tobacco leaves, the preparation method of which differs from that in Example 1, is as follows: In step S1, a 25% tetrapropylammonium hydroxide (TPAOH) solution was selected, and tetraethyl orthosilicate (TEOS), tetrabutyl titanate, and tetrapropylammonium hydroxide were mixed in a mass ratio of 3:2:5. The mixture was stirred at 85°C for 2 hours to form a homogeneous gel. The resulting gel was transferred to a sealed reaction vessel and crystallized at 160°C for 48 hours. After the reaction was completed, the mixture was cooled to room temperature and filtered to obtain a solid product. The solid product was washed with deionized water until neutral and then dried at 120°C for 12 hours. The powder was then calcined at 600℃ in air for 8 hours to obtain white titanium-silicon molecular sieve powder. The powder was added to a 0.05 mol / L zinc lactate solution at a solid-liquid ratio of 5 g:100 mL, stirred at 25℃ for 12 hours, allowed to settle, the supernatant was removed, and the mixture was filtered to obtain a wet filter cake. This wet filter cake was slowly evaporated to dryness at 120℃, and then calcined at 700℃ under N2 for 12 hours to obtain a light blue zinc-modified titanium-silicon molecular sieve, which is the low-temperature catalytic material. The titanium-silicon molecular sieve prepared under the above conditions has a stable pore size in the range of approximately 0.5–0.6 nm, an average particle size of approximately 50–70 μm, and exhibits a short rod-shaped or irregular particle morphology.
[0044] Steps S2 and S3 are the same as in Example 1, obtaining a low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves. Reconstituted tobacco leaves are then prepared according to the method in Example 1.
[0045] The pyrolysis diagram of the product in this embodiment is as follows: Figure 2 As shown, compared to Figure 1 As a result, Figure 2 Overall reaction curve and Figure 1 Similar, but the reaction temperature is relatively... Figure 1 Slight lag, reaction temperature slightly higher Figure 1The reaction terminated at around 320℃, and the final remaining mass was slightly larger, indicating that Example 2 still has good low-temperature aroma release ability compared to traditional reconstituted tobacco, but the overall reaction temperature is slightly worse than that of Example 1. That is, this reconstituted tobacco sample releases aroma at 252℃, has good thermal conductivity, and releases aroma relatively slowly, making it suitable for medium-temperature use scenarios.
[0046] Example 3 A low-temperature aroma-releasing thermally conductive adhesive for heated cigarette reconstituted tobacco leaves, the preparation method of which differs from that in Example 1, is as follows: In step S1, a 20% tetrapropylammonium hydroxide (TPAOH) solution was selected, and tetraethyl orthosilicate (TEOS), tetrabutyl titanate, and tetrapropylammonium hydroxide were mixed in a mass ratio of 1:1:8. The mixture was stirred at 75°C for 2 hours to form a homogeneous gel. The resulting gel was transferred to a sealed reaction vessel and crystallized at 180°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature and filtered to obtain a solid product. The solid product was washed with deionized water until neutral, then dried at 120°C for 12 hours, and finally calcined at 600°C in air. After 8 hours, titanium-silicon molecular sieve powder was obtained. The powder was added to a 0.05 mol / L copper acetate solution at a solid-liquid ratio of 5 g: 100 mL. The mixture was stirred at 25 °C for 12 hours, allowed to settle, and the supernatant was removed. A wet filter cake was obtained by filtration. The wet filter cake was slowly evaporated to dryness at 120 °C, and then calcined at 700 °C under N2 conditions for 12 hours to obtain a low-temperature catalytic material. The titanium-silicon molecular sieve prepared under these conditions has an MFI-type microporous structure with a stable pore size in the range of approximately 0.4–0.5 nm. The grains are distributed at the submicron level, with an average particle size of approximately 60–80 μm. The overall morphology is short rod-shaped or irregular, exhibiting a high external specific surface area and good dispersibility.
[0047] In S2, alumina powder with a particle size of 80 μm was taken, and the other methods were the same as in Example 1 to obtain the thermally conductive filler.
[0048] In S3, soluble starch was dissolved in deionized water at a mass-to-volume ratio of 2g:100mL and heated at 60°C until fully gelatinized to form a uniform matrix colloid; other methods were the same as in Example 1 to obtain a low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves for heated cigarettes.
[0049] Reconstituted tobacco leaves were prepared according to the method in Example 1.
[0050] The aroma release temperature of the reconstituted tobacco leaf was tested. The reconstituted tobacco leaf sample could release aroma significantly at 248℃, and the sheet had good flexibility, making it suitable for use in curved and irregularly shaped areas.
[0051] Comparative Example 1 A low-temperature aroma-releasing thermally conductive adhesive for heated cigarette reconstituted tobacco leaves is prepared in a manner different from that in Example 1. The white titanium-silicon molecular sieve powder obtained in step S1 is used as the low-temperature catalytic material, and no metal-organic salt modification is performed. The titanium-silicon molecular sieve prepared at this time has a stable pore size in the range of about 0.4~0.5 nm, an average particle size of about 50~60 μm, a white color, and an overall short rod-shaped or irregular particle morphology.
[0052] The other preparation methods are the same as in Example 1. Reconstituted tobacco leaves were prepared according to the method in Example 1. The aroma release temperature of the reconstituted tobacco leaves was tested. A significant aroma release was only observed at approximately 295°C, indicating a delayed aroma release that does not meet the requirements for low-temperature applications.
[0053] Comparative Example 2 A thermally conductive adhesive for low-temperature aroma release from reconstituted tobacco leaves for heated cigarettes is prepared in a manner that differs from that in Example 1 in that: no silane coupling agent is added in S2, and alumina powder, anhydrous ethanol and stainless steel balls are directly mixed, ball-milled, washed and dried to obtain the thermally conductive filler.
[0054] Other preparation methods are the same as in Example 1. Reconstituted tobacco leaves were prepared according to the method in Example 1.
[0055] During the testing process, the thermally conductive adhesive in the reconstituted tobacco sample was unevenly distributed, had poor thermal conductivity, showed a significant increase in local temperature, exhibited unstable aroma release, and showed signs of cracking in the leaf pieces. This indicates that the unmodified filler was unable to form an effective interface with the colloid.
[0056] Comparative Example 3 A low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves for heated cigarettes is prepared in a manner that differs from that in Example 1 in that vacuum stirring is not used in step S3, but only stirring is performed under normal pressure for 1 hour to obtain the low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves for heated cigarettes.
[0057] Other preparation methods are the same as in Example 1. Reconstituted tobacco leaves were prepared according to the method in Example 1.
[0058] Residual air bubbles, uneven colloid mixing, large fluctuations in aroma release temperature, and insufficient aroma release in some areas were observed in the reconstituted tobacco sample. At the same time, the thermal conductivity was reduced to below 0.38 W / m•K, which proves that the vacuum stirring process has a significant effect on ensuring the homogeneity and functional stability of the colloid.
[0059] Comparative Example 4 A low-temperature aroma-releasing thermally conductive adhesive for heated cigarette reconstituted tobacco leaves is prepared in a way that differs from that in Example 1 in that: in S2, ball milling is not performed, and the obtained dried modified powder is directly used as a thermally conductive filler.
[0060] Other preparation methods are the same as in Example 1. Reconstituted tobacco leaves were prepared according to the method in Example 1.
[0061] The electron scanning microscope image of the reconstituted tobacco leaf prepared in this comparative example is shown below. Figure 4 As shown, compared to Figure 3 Larger particles can be observed, and some agglomeration of the white thermally conductive filler and molecular sieve can be observed. After heating, the agglomerated parts are prone to causing holes in the reconstituted tobacco leaves, resulting in tobacco leaf breakage and a decrease in the overall strength of the tobacco leaves. This proves that the filler after ball milling is finer and causes less damage to the structure of the reconstituted tobacco leaves. The ball milling process has a significant effect on ensuring the uniform dispersion of molecular sieves in reconstituted tobacco leaves and the integrity of the reconstituted tobacco leaves.
[0062] The low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves prepared in this invention uses organometallic salt-modified titanium-silicon molecular sieves as a catalytic material, without adding precious metals, thus avoiding the problem of precious metal recovery from tobacco cartridge waste. Thermally conductive fillers such as metals, nitrides, carbon, and carbides have problems such as metals being easily oxidized, causing deterioration of reconstituted tobacco leaves; nitrides having excessive hardness, which is detrimental to the processing of reconstituted tobacco leaves; and carbon and carbides having a darker color, affecting the sensory properties of reconstituted tobacco leaves. Metal oxides, on the other hand, exhibit stable properties. In the technical solution of this invention, the titanium-silicon molecular sieve and the thermally conductive filler form a synergistic effect of heat transfer and catalysis in the reconstituted tobacco system. The thermally conductive filler constructs the heat conduction path and improves the overall thermal conductivity of the system, enabling heat to be transferred more evenly to each area, thereby allowing the reconstituted tobacco to quickly reach the effective temperature range for the titanium-silicon molecular sieve to exert its catalytic effect. On this basis, the titanium-silicon molecular sieve reduces the activation energy required for the release of tobacco flavor substances through its microporous structure and active sites, achieving effective aroma release under low temperature conditions. The synergy between the two can transform local aroma release into overall uniform aroma release, thereby improving the uniformity and stability of smoke release while reducing the aroma release temperature, and improving the consistency of the taste of heated cigarettes.
[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A low-temperature aroma-releasing thermally conductive adhesive for heated cigarette reconstituted tobacco leaves, characterized in that, It comprises the following components in parts by weight: 2-6 parts of low-temperature catalytic material, 0.8-1.2 parts of thermally conductive filler, and 100 parts of matrix colloid; wherein the low-temperature catalytic material is an organometallic salt modified titanium-silicon molecular sieve, and the thermally conductive filler is a silane coupling agent modified metal oxide powder.
2. The low-temperature aroma-releasing thermally conductive adhesive for heated cigarette reconstituted tobacco leaves as described in claim 1, characterized in that, The particle size of the thermally conductive filler is 50~80μm, and the particle size of the molecular sieve is 70~100μm.
3. A method for preparing a low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves for heated cigarettes as described in any one of claims 1-2, characterized in that, Includes the following steps: Low-temperature catalytic materials and thermally conductive fillers are added to the matrix colloid and stirred under vacuum at 40~60℃ for 1~1.5h to obtain a low-temperature aroma-releasing thermally conductive colloid for reconstituted tobacco leaves for heated cigarettes.
4. The preparation method of the low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves in heated cigarettes as described in claim 3, characterized in that, The preparation method of the low-temperature catalytic material includes: adding tetraethyl orthosilicate and tetrabutyl titanate in a mass ratio of (1~3):(1~2) to a tetrapropylammonium hydroxide solution, synthesizing a gel at 70~90℃, crystallizing at 160℃~180℃ for 24~48 h, cooling and drying, and then calcining at 600℃~800℃ for 8~10 h to obtain a titanium silicon molecular sieve, adding the titanium silicon molecular sieve to a metal-organic salt solution with a concentration of 0.03~0.07mol / L, stirring and filtering the solid, evaporating and drying, and then calcining at 600~800℃ for 12~14 h to obtain the low-temperature catalytic material.
5. The preparation method of the low-temperature aroma-releasing thermally conductive adhesive for heated cigarette reconstituted tobacco leaves as described in claim 4, characterized in that, The concentration of the tetrapropylammonium hydroxide solution is 20%~30%, preferably 25%, and the mass ratio of tetraethyl orthosilicate, tetrabutyl titanate to tetrapropylammonium hydroxide is (1~3):(1~2):(2~8). Alternatively, organometallic salts include one or more of copper acetate, ammonium molybdate, and phosphotungstic acid.
6. The preparation method of the low-temperature aroma-releasing thermally conductive adhesive for heated cigarette reconstituted tobacco leaves as described in claim 3, characterized in that, The preparation method of the thermally conductive filler includes: adding metal oxide powder to a silane coupling agent solution, stirring and reacting to obtain modified metal oxide powder, and ball milling the modified metal oxide powder to obtain the thermally conductive filler.
7. The preparation method of the low-temperature aroma-releasing thermally conductive adhesive for heated cigarette reconstituted tobacco leaves as described in claim 6, characterized in that, The metal oxide powder includes one or more of aluminum oxide, magnesium oxide and zinc oxide, with a particle size of 50~80μm; Alternatively, the silane coupling agent comprises triethoxysilane, and the concentration of the silane coupling agent solution is 3~7 mg / mL; Alternatively, the solvent for the silane coupling agent is ethanol; Alternatively, stir for 1-2 hours, let stand for 1-2 hours, wash with ethanol, and dry to obtain the modified metal oxide powder.
8. The preparation method of the low-temperature aroma-releasing thermally conductive adhesive for heated cigarette reconstituted tobacco leaves as described in claim 6, characterized in that, During ball milling, the modified metal oxide powder and stainless steel balls are added to anhydrous ethanol at a mass ratio of 1:(5~6), and ball milled at a speed of 300~500 r / min for 6~12 h. After cleaning, the mixture is dried.
9. The application of a low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves as described in any one of claims 1-2 in the preparation of reconstituted tobacco leaves, characterized in that, include: After mixing tobacco powder, CMC and glycerol, the low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves is added, and the mixture is then used to prepare reconstituted tobacco leaves.
10. The application of the low-temperature aroma-releasing thermally conductive adhesive for reconstituted tobacco leaves as described in claim 9 in the preparation of reconstituted tobacco leaves, characterized in that, The mass ratio of tobacco powder, CMC, glycerol and the low-temperature aroma-releasing thermally conductive adhesive of the heated cigarette reconstituted tobacco is 100: (1~2): (30~40): (1~2).