Multilayer heat-insulating cigarette paper for heat-not-burn cigarettes

Abstract

The application discloses a multi-layer heat preservation and insulation cigarette paper for a heat-not-burn cigarette, which has a multi-layer composite structure and sequentially comprises an inner layer and an outer layer from inside to outside; the inner layer has a heat radiation emission function and a multi-layer heat insulation function; and the outer layer has a heat radiation reflection function; the inner layer is composed of a high-temperature-resistant high-heat-radiation-emissivity base material and aerogel with low thermal conductivity; the base material has a cellular structure and low thermal conductivity, and can reduce the heat loss of the internal tobacco towards the outside. The multi-layer heat preservation and insulation cigarette paper is designed with the outer layer having the heat radiation reflection function, and the outer layer can return the heat radiation of the inner layer to the tobacco, so that the heat loss can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-temperature non-combustion electronic cigarettes, and more particularly to a multi-layer heat-insulating cigarette paper for a heat-not-burn cigarette. BACKGROUND

[0002] For a heat-not-burn cigarette, the smoking section or heating section is heated to a certain temperature by heating processed tobacco (special tobacco cartridge), but not lighting the tobacco, so that the tobacco is heated to a sufficient degree to emit smoke. Therefore, the section needs to be heated at a high temperature of up to 300 o C or so. While ensuring high heating efficiency, preventing heat overflow to cause overheating of the outside of the cigarette is a problem that must be considered for the smoking / heating section of the heat-not-burn cigarette.

[0003] At present, the heat-insulating cigarette paper for the smoking / heating section of the heat-not-burn cigarette mainly uses the following materials: silica aerogel, glass fiber cloth and glass fiber felt, heat-insulating cotton, and composite cigarette paper with an aluminum foil layer. Among them, Chinese patent CN 105200865 selects silica aerogel and micrometer titanium dioxide particles to prepare a heat-insulating layer. Chinese patent CN201010563640.5 uses super glass fiber, coniferous wood pulp, and a polyvinyl alcohol aqueous solution mixture, and Chinese patent CN109291558 prepares a heat-insulating material composed of a glass fiber felt layer and a glass fiber cloth layer. Chinese patent CN109793264 prepares a heat-insulating felt using glass fiber, a binder, and an additive. The heat-insulating layer prepared by Chinese patent CN 105747280 is made of glass fiber, ceramic, foamed plastic, or a vacuum heat-insulating plate. Chinese patents CN 109998174, CN203597395, and CN 208490828 use heat-insulating aluminum foil cotton for heat insulation. Chinese patent CN 105011377 uses an aluminum foil heat-insulating roll material or a polyurethane heat-insulating layer material. The heat-insulating layer of Chinese patent CN 204224922 is composed of an aluminum foil and inorganic materials such as calcium carbonate, calcium sulfate, aluminum hydroxide and its hydrate, and aluminum oxide. The heat-insulating layers involved in the above patents all achieve the function of heat insulation by reducing the thermal conductivity.

[0004] However, pure low-thermal-conductivity materials often have difficulty in meeting the requirements of low thickness and high heat insulation, and the heat of the cigarette is difficult to be fully utilized due to the influence of the heating method. Based on the above analysis, there is currently no effective heat-insulating cigarette paper that can simultaneously meet the requirements of low thickness, high heat insulation, and high heat utilization efficiency.

[0005] Therefore, the present application intends to design a multifunctional heat-insulating and heat-preserving film that combines heat radiation heat preservation, radiation reflection heat preservation, aerogel, and foamed material heat insulation technologies. SUMMARY

[0006] The present application aims to provide a multi-layer thermal insulation cigarette paper for heat-not-burn cigarettes, so as to solve the above technical problems.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] A multi-layer thermal insulation cigarette paper for heat-not-burn cigarettes, the cigarette paper has a multi-layer composite structure, and the inner layer and the outer layer are sequentially arranged from inside to outside; the inner layer has a thermal radiation emission function and a multi-layer thermal insulation function; the outer layer has a thermal radiation reflection function.

[0009] The inner layer is composed of a high-temperature-resistant high-thermal-radiation-emissivity base material and a low-thermal-conductivity aerogel, and the base material has a pore structure.

[0010] In some embodiments, the outer layer is composed of a high-temperature-resistant base material and a metal flake having a thermal radiation reflection function.

[0011] In some embodiments, the inner layer base material includes one or more of polyvinylpyrrolidone, polyvinyl alcohol, cellulose, polyimide, polyether ether ketone, and polyphenylene sulfide.

[0012] In some embodiments, the low-thermal-conductivity aerogel in the inner layer is a combination of one or more of the following: silicon dioxide and titanium dioxide.

[0013] In some embodiments, the particle size of the aerogel is 0.2-2.0 microns, and the weight content is 5-8 wt.%.

[0014] In some embodiments, the thickness of the inner layer is 30-50 microns.

[0015] In some embodiments, the outer layer base material is a combination of one or more of the following: polyvinylpyrrolidone, polyvinyl alcohol, cellulose, polyimide, polyether ether ketone, and polyphenylene sulfide.

[0016] In some embodiments, the metal flake having a thermal radiation reflection function in the outer layer is a combination of one or more of the following metals: silver, aluminum, and iron, wherein the weight content of the metal flake is 10-15 wt.%.

[0017] In some embodiments, the thickness of the outer layer is 10-20 microns.

[0018] The multi-layer thermal insulation cigarette paper for heat-not-burn cigarettes provided in the present application has the following beneficial effects, including but not limited to:

[0019] The application provides a design and a preparation method of a novel high-temperature-resistant cigarette paper with excellent heat insulation performance for heating non-combustible cigarettes. An outer layer with heat radiation reflection function is designed, which can return the heat radiated by the inner layer to the tobacco, thereby reducing heat loss. Since the main component of the outer layer with heat radiation reflection function is metal, which has high thermal conductivity, in order to reduce the conduction loss of heat in the outer layer, a multi-level bubble structure is designed in the inner layer, which can significantly prolong the heat conduction path and reduce the heat conduction path, so the thermal conductivity is extremely low, and the tobacco has a very good heat preservation effect. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structural schematic diagram of a multi-layer heat insulation cigarette paper for heating non-combustible cigarettes according to the embodiment; DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the application clearer, the technical scheme in the embodiments of the application will be described in more detail below with reference to the drawings of the preferred embodiments of the application. In the drawings, the same or similar notations represent the same or similar parts or parts with the same or similar functions throughout. The described embodiments are part of the embodiments of the application, not all embodiments. The embodiments described below by reference to the drawings are exemplary and are intended to explain the application, and cannot be understood as a limitation of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0022] The embodiments of the application will be described in detail below with reference to the drawings.

[0023] In the description of the application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0024] In the description of the application, it should be understood that the terms "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation of the application.

[0025] Moreover, the terms "comprising" and "including" and any variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, system, product or display that comprises a list of steps or elements not merely consists of those specifically identified herein, but can include additional steps or elements not expressly listed or inherent to such process, method, product, or display.

[0026] The following will be described in detail Figure 1 A new multi-layer thermal insulation cigarette paper for heat-not-burn cigarettes is described in detail. It is worth noting that the following examples are used to explain the present application and do not constitute a limitation on the present application.

[0027] As Figure 1 shown, a new multi-layer thermal insulation cigarette paper for heat-not-burn cigarettes, the cigarette paper has a multi-layer composite structure, from inside to outside, in turn, the inner layer 1 and the outer layer 2. The inner layer has thermal radiation emission function and multi-layer insulation function; the outer layer has thermal radiation reflection function.

[0028] The inner layer is composed of high-temperature-resistant high-thermal-radiation-emissivity matrix material and aerogel with extremely low thermal conductivity. The matrix material has a cellular structure.

[0029] The outer layer is composed of high-temperature-resistant matrix material and metal sheet with thermal radiation reflection function.

[0030] After absorbing the heat of the tobacco, the inner layer material can return the heat to the tobacco in the form of radiation. Since thermal radiation radiates both inward and outward, in order to prevent heat loss and reduce heat utilization, an outer layer with thermal radiation reflection function is designed. This layer can return the heat radiated by the inner layer to the tobacco, thus reducing heat loss.

[0031] Since the main component of the outer layer's thermal radiation reflection function is metal, which has high thermal conductivity, in order to reduce the heat conduction loss in the outer layer, a multi-layer cellular structure is designed in the inner layer, which can significantly extend the heat conduction path and reduce the heat conduction path, thus the thermal conductivity is extremely low, which has good thermal insulation effect on the tobacco.

[0032] In the above scheme, the inner layer matrix material is a combination of one or more of the following: polyvinylpyrrolidone, polyvinyl alcohol, cellulose, polyimide, polyether ether ketone, polyphenylene sulfide, etc.

[0033] In the above scheme, the aerogel with extremely low thermal conductivity in the inner layer is a combination of one or more of the following: silicon dioxide, titanium dioxide, etc. The aerogel particle size is 0.2-2.0 microns, and the weight content is 5-8 wt.%.

[0034] In the above aspect, the inner layer foaming method can be one of physical foaming, chemical foaming, etc.

[0035] In the above aspect, the inner layer thickness is 30-50 microns.

[0036] In the above aspect, the outer layer base material is one or a combination of polyvinylpyrrolidone, polyvinyl alcohol, cellulose, polyimide, polyether ether ketone, polyphenylene sulfide, etc.

[0037] In the above aspect, the metal flake in the outer layer having heat radiation reflection function is one or a combination of silver, aluminum, iron, etc. The weight content is 10-15 wt.%.

[0038] In the above aspect, the outer layer thickness is 10-20 microns.

[0039] The inner layer foaming can be achieved by placing the pretreated polyimide precursor and aerogel powder on a flat plate, keeping the temperature at 160°C for 10 min, then increasing the temperature to 180°C at a rate of 3°C / min, keeping the temperature constant for 70 min, and then heat treating at 260°C for 50 min to obtain the polyimide foaming layer containing aerogel, i.e. the multi-level thermal insulation layer.

[0040] The spraying outer layer can be achieved by adding flaky aluminum powder into the polyimide solution to form a polyimide mixed solution. Then, the polyimide mixed solution is sprayed onto the surface of the polyimide foaming layer using a spray gun to prepare a radiation reflection layer on the surface of the polyimide foaming layer, and the inner and outer layers are combined to form a multi-level high-performance thermal insulation film.

[0041] The thermal insulation performance test method can be achieved by winding the thermal insulation film around the tobacco, heating the center part of the tobacco to 350°C, and then immediately testing the surface temperature using an infrared temperature measuring instrument.

[0042] Example 1

[0043] Inner layer foaming: The pretreated polyimide precursor and 5% by weight of SiO2 aerogel powder with a particle size of 0.2 microns are placed on a flat plate, kept at 160°C for 10 min, then increased to 180°C at a rate of 3°C / min, kept constant for 70 min, and then heat treated at 260°C for 50 min to obtain a polyimide foaming layer containing aerogel with a thickness of 30 microns, i.e. a multi-level thermal insulation layer. The cell size is about 15 microns, and the foaming layer density is about 0.02 g / cm 3 .

[0044] Spraying outer layer: 10% by weight of flaky aluminum powder was added into the polyimide solution to form a polyimide mixed solution. Then the polyimide mixed solution was sprayed onto the surface of the polyimide foaming layer using a spray gun to prepare an infrared reflective layer with a thickness of 20 microns on the surface of the polyimide foaming layer. After the inner and outer layers were combined, a high-performance thermal insulation film with a multi-level structure was formed.

[0045] Example 2

[0046] Inner layer foaming: Different from Example 1, the weight ratio of aerogel particles was 8%, the particle size was 0.5 microns, the cell size of the foaming layer was about 13 microns, and the density of the foaming layer was about 0.15 g / cm 3 .

[0047] Spraying outer layer: The only difference from Example 1 was that the thickness of the infrared reflective layer was 20 microns.

[0048] Example 3

[0049] Inner layer foaming: Different from Example 1, the size of the aerogel particles was 1.0 microns, the cell size of the foaming layer was about 14 microns, and the density of the foaming layer was about 0.13 g / cm 3 , and the thickness of the foaming layer was 40 microns.

[0050] Spraying outer layer: The only difference from Example 1 was that the thickness of the infrared reflective layer was 15 microns.

[0051] Example 4

[0052] Inner layer foaming: Different from Example 1, the weight ratio of aerogel particles was 8%, the size of the aerogel particles was 1.5 microns, the cell size of the foaming layer was about 13 microns, and the density of the foaming layer was about 0.13 g / cm 3 , and the thickness of the foaming layer was 40 microns.

[0053] Spraying outer layer: Different from Example 1, the weight content of aluminum flakes was 15%, and the thickness of the infrared reflective layer was 15 microns.

[0054] Example 5

[0055] Inner layer foaming: Different from Example 1, the size of the aerogel particles was 2.0 microns, the cell size of the foaming layer was about 12 microns, and the density of the foaming layer was about 0.14 g / cm 3 , and the thickness of the foaming layer was 50 microns.

[0056] Spraying outer layer: Different from Example 1, the weight content of aluminum flakes was 15%, and the thickness of the infrared reflective layer was 20 microns.

[0057] Comparative Example 1

[0058] Inner layer foaming: Different from Example 1, the aerogel particles were not contained, the cell size of the foamed layer was about 16 microns, and the density of the foamed layer was about 0.11 g / cm3. 3 .

[0059] Sprayed outer layer: Different from Example 1, the weight content of the aluminum sheet was 10%, and the thickness of the infrared reflective layer was 15 microns.

[0060] Comparative Example 2

[0061] Inner layer foaming: Different from Example 1, there was no foaming process, the weight content of the aerogel particles was 8%, and the thickness of the foamed layer was 40 microns.

[0062] Sprayed outer layer: Different from Example 1, the weight content of the aluminum sheet was 15%, and the thickness of the infrared reflective layer was 15 microns.

[0063] Comparative Example 3

[0064] Inner layer foaming: Different from Example 1, the size of the aerogel particles was 0.5 micron, the cell size of the foamed layer was about 14 microns, the density of the foamed layer was about 0.13 g / cm3, and the thickness of the foamed layer was 40 microns. 3

[0065] Sprayed outer layer: Different from Example 1, the aluminum sheet was not contained, and the thickness of the infrared reflective layer was 15 microns.

[0066] Table 1 Structure parameters and thermal insulation properties of the experimental examples and comparative examples

[0067] Serial number Matrix Inner layer thickness (pm) Outer layer thickness (pm) SiO2 aerogel content (wt. %) SiO2 aerogel size (pm) PI foamed inner layer density (g / cm 3 )]> PI inner layer cell size (pm) Aluminum flake content (wt. %) Cigarette paper outer surface temperature (°C) Example 1 Foamed PI 30 10 5 0.2 0.12±0.02 15±2 10 51±1 Example 2 Foamed PI 30 20 8 0.5 0.15±0.02 13±2 10 49±1 Example 3 Foamed PI 40 15 5 1.0 0.13±0.02 14±2 10 45±1 Example 4 Foamed PI 40 15 5 1.5 0.13±0.02 13±2 15 43±1 Example 5 Foamed PI 50 20 5 2.0 0.14±0.02 12±2 15 40±1 Comparative Example 1 Foamed PI 40 15 0 - 0.11±0.02 16±2 10 48±1 Comparative Example 2 Unfoamed PI 40 15 8 0.2 - - 15 50±1 Comparative Example 3 Foamed PI 40 15 5 0.5 0.13±0.02 14±2 0 48±1

[0068] After the test, the properties of each example and comparative example were shown in Table 1. From the results, it can be seen that Examples 3, 4 and 5 had the best thermal insulation effect, which was due to the thicker inner layer (i.e. thermal insulation), the higher content of the metal aluminum sheet, the larger size of the silica aerogel particles and the smaller cell size. By comparison, Example 2 had a high content of aerogel of 8%, but the thickness of the inner layer was only 30 microns, which was probably the main reason for the poor final thermal insulation property. Example had a small size and low content (5%) of aerogel, and the thickness of the foamed layer was also only 30 microns, so the thermal insulation effect was not ideal. From the three comparative examples, either no aluminum sheet was contained, so there was no infrared reflection effect, or there was no foaming, so the thermal conductivity was high and the thermal insulation property was poor, or no aerogel was contained, so it did not have a multi-level cell structure, resulting in poor thermal insulation property. Therefore, the three factors were very important and played a decisive role in the thermal insulation property. However, the thermal insulation property of Example 1 was poor, even worse than that of the comparative examples, which was mainly due to the small thickness. This was also verified by the fact that Example 5 had the largest thickness (50 microns) and thus obtained the best thermal insulation property.

[0069] ​The above merely describes preferred embodiments of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A multi-layer heat-insulating cigarette paper for heat-not-burning cigarettes, characterized in that, The cigarette paper has a multi-layered composite structure, consisting of an inner layer and an outer layer from the inside out; the inner layer has heat radiation emission function and multi-layered heat insulation function; the outer layer has heat radiation reflection function. The inner layer is composed of a high-temperature resistant, high-thermal-emissivity matrix material and a low-thermal-conductivity aerogel. The matrix material has a porous structure. The inner layer is obtained by placing a pretreated polyimide precursor and aerogel powder on a flat plate, holding the temperature at 160°C for 10 minutes, then increasing the temperature to 180°C at a rate of 3°C / min, holding the temperature for 70 minutes, and then heat-treating at 260°C for 50 minutes to obtain a polyimide foam layer containing aerogel. The outer layer is composed of a high-temperature resistant matrix material and a metal sheet with thermal radiation reflection function. The outer layer is obtained by mixing sheet aluminum powder into a polyimide solution to form a polyimide mixed solution. Then, the polyimide mixed solution is sprayed onto the surface of the polyimide foam layer using a spray gun to prepare a radiation reflection layer on the surface of the polyimide foam layer. The inner and outer layers are combined to form a multi-layered high-performance thermal insulation film.

2. The multi-layer heat-insulating cigarette paper for heated non-combustible cigarettes according to claim 1, characterized in that, The aerogel with low thermal conductivity in the inner layer is one or more of the following combinations: silicon dioxide and titanium dioxide.

3. The multi-layer heat-insulating cigarette paper for heated non-combustible cigarettes according to claim 2, characterized in that, The aerogel has a particle size of 0.2-2.0 micrometers and a weight content of 5-8 wt.%.

4. The multi-layer heat-insulating cigarette paper for heated non-combustible cigarettes according to claim 1, characterized in that, The inner layer has a thickness of 30-50 micrometers.

5. The multi-layer heat-insulating cigarette paper for heated non-combustible cigarettes according to claim 1, characterized in that, The metal sheet contains 10-15 wt.% of its weight.

6. The multi-layer heat-insulating cigarette paper for heated non-combustible cigarettes according to claim 1, characterized in that, The outer layer has a thickness of 10-20 micrometers.

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