A heat-responsive smoke gain filter rod forming paper and preparation and application thereof

Abstract

The present application belongs to the field of cigarette functional materials and smoke gain technology, and provides a heat-responsive smoke gain filter rod forming paper and its preparation and application. The filter rod forming paper comprises a filter rod forming paper base material and a functional thin coating layer coated on the inner surface of the base material side facing the acetate fiber tow. The functional thin coating layer comprises a bonding glue layer and a temperature-sensitive anchoring system dispersed and fixed in the bonding glue layer. The temperature-sensitive anchoring system comprises a porous carrier and temperature-sensitive plant essential oil microcapsules. The microcapsules are partially embedded in the micropores inside the porous carrier or physically adsorbed on the outer surface, and the microcapsules are constrained by the porous carrier skeleton. The temperature-sensitive plant essential oil microcapsules comprise a plant essential oil core material and a phase change wall material covering the plant essential oil core material. The phase change wall material is selected from food-grade aliphatic phase change materials with a phase change temperature of 40-50 DEG C. The present application can realize the integrated effect of synchronous aroma release during smoking, smoke gain, and long-term stable function, and can significantly improve the sensory quality of low-tar and high-filter cigarettes.

Description

Technical Field

[0001] This application relates to the field of functional materials for cigarettes and smoke gain technology, and in particular to a thermally responsive smoke gain filter rod forming paper and its preparation and application. Background Technology

[0002] Under the dual policy guidance of tobacco control and compliance, the tobacco industry is accelerating its transformation and upgrading towards low-harm, functional, and high-quality products. How to balance the smoking experience with public health needs through technological innovation has become a core issue for the industry's high-quality development. Currently, the continuous physical and chemical stimulation of the throat and airway caused by cigarette smoke during inhalation easily leads to discomfort such as dry throat, itchy throat, cough, and mucosal congestion. Traditional tar reduction and harm reduction technologies are no longer sufficient to meet consumers' dual demands for health attributes and sensory comfort. Although natural plant essential oils have good application potential in moisturizing smoke and soothing the throat, conventional addition methods suffer from problems such as easy volatility at room temperature, poor stability, uncontrollable release, and easy migration and oil separation, making it difficult to meet the requirements of industrial applications.

[0003] Existing research indicates that during cigarette smoking, the combustion end temperature is extremely high. However, after the smoke passes through the filter rod to moisten the smoke and reduce irritation and heat dissipation, the surface temperature of the outer forming paper of the filter rod stabilizes at 40℃~50℃, with a peak temperature not exceeding 55℃. In publicly available technologies, temperature-sensitive controlled-release microcapsules are mostly used inside the filter rod, using synthetic polymers as the wall material. The response temperature is concentrated above 50℃, which is mismatched with the surface temperature field of the forming paper (40℃~50℃). More importantly, the industry has long lacked a systematic solution that addresses the surface load of the forming paper, responds to both inhalation and temperature changes, and simultaneously provides functions such as moistening the smoke, reducing irritation and soothing the nerves, and enhancing sensory experience.

[0004] For example, patent CN117356750B discloses a temperature-sensitive flavoring microcapsule for a functional filter rod and its preparation method, comprising a porous carrier, flavorings adsorbed within the porous carrier, and a sealing film coating the surface of the porous carrier; in the sealing film, the mass ratio of palm oil to coconut oil is 1:0.5-2. When the mass ratio of palm oil to coconut oil is 1:0.5-2, the sealing film is solid at room temperature (25-35℃), effectively encapsulating the flavorings adsorbed within the porous carrier and preventing their volatilization. However, when smoking, the filter temperature is around 55℃. At this temperature, the sealing film melts, becoming liquid, losing its encapsulating effect on the flavorings, allowing them to volatilize rapidly and enhance the aroma of the smoke. The prior art lacks a single-sided coating structure on the inner side of the forming paper, does not incorporate a porous carrier anchoring system, and has a relatively high microcapsule phase transition temperature (around 55°C), which is incompatible with the 40-50°C suction temperature range of the filter rod forming paper. This results in easy oil separation and powder shedding during long-term storage, failing to address the industry pain points of fragrance blockage and long-lasting fragrance release in forming paper. Therefore, it is fundamentally different from the technical solution of this invention. Thus, overcoming the limitations of existing natural plant essential oils—such as high volatility, low retention rate, and poor smoke transfer efficiency—and developing a temperature-sensitive controlled-release technology adapted to the operating conditions of forming paper has significant research value and application prospects. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a thermally responsive smoke-enhancing filter rod forming paper, its preparation and application, which can achieve the integrated effect of simultaneous aroma release during inhalation, smoke enhancement, and long-term stable function, and can significantly improve the sensory quality of low-tar, high-filtration cigarettes.

[0006] To achieve the above and related objectives, the present invention employs the following technical means:

[0007] The first aspect of the present invention provides a thermally responsive flue gas gain filter rod forming paper, comprising a filter rod forming paper substrate and a functional thin coating applied to the inner surface of the substrate on the side facing the cellulose acetate bundle;

[0008] The functional thin coating includes an adhesive layer and a temperature-sensitive anchoring system dispersed and fixed in the adhesive layer. The temperature-sensitive anchoring system includes a porous carrier and temperature-sensitive plant essential oil microcapsules. The temperature-sensitive plant essential oil microcapsules are partially embedded in the micropores of the porous carrier or physically adsorbed on the outer surface of the porous carrier, and the temperature-sensitive plant essential oil microcapsules are constrained by the porous carrier skeleton.

[0009] Among them, the thermosensitive plant essential oil microcapsule includes a plant essential oil core material and a phase change wall material that encapsulates the plant essential oil core material. The phase change wall material is a food-grade aliphatic phase change material with a phase change temperature of 40℃~50℃.

[0010] As can be seen from the above technical means, this application precisely defines the functional thin coating on the inner surface of the substrate facing the cellulose acetate bundle. This ensures that the temperature-sensitive plant essential oil microcapsules are located in the mainstream flue gas channel, facilitating the efficient transfer of essential oils to the flue gas, while avoiding contamination of the appearance surface and negative impacts on the ventilation rate of the filter rod, thus preserving the air permeability of the original paper. Furthermore, this application innovatively constructs a temperature-sensitive anchoring system of "porous carrier anchoring + microcapsule controlled release": utilizing the rich microporous structure of the porous carrier, it provides physical embedding and adsorption sites for the microcapsules, significantly enhancing the binding strength of the microcapsules in the adhesive layer, effectively inhibiting the risks of migration, oil separation, and powder shedding during storage, thereby solving the problem of easy agglomeration and detachment of functional particles in traditional coating layers.

[0011] Furthermore, the temperature-sensitive plant essential oil microcapsules of this application use food-grade aliphatic phase change material with a phase change temperature of 40℃~50℃ as the wall material. This temperature range closely matches the actual temperature rise range of the filter rod forming paper surface during cigarette smoking. At room temperature, the wall material is a solid, sealed core material, improving the storage stability of the essential oil and preventing volatilization loss. At the moment of inhalation, the wall material senses the change in the thermal field and undergoes a phase change and melts, intelligently breaking open the capsule to release the essential oil. This precisely achieves dynamic controlled release of "response upon inhalation and sealing upon cessation of inhalation," thereby avoiding ineffective release while warming the smoke, reducing impurities, and soothing the throat, significantly improving the targeting and utilization rate of the smoke enhancement effect. In addition, the selection of food-grade aliphatic phase change material in this application ensures that no harmful substances are generated at the decomposition temperature and does not interfere with the original aroma and style of the cigarette, taking into account both safety and sensory quality.

[0012] Furthermore, the wet coating thickness of the functional thin coating is 8 μm to 10 μm, and the area loading of the temperature-sensitive plant essential oil microcapsules on the substrate in the dry state is 0.8 g / m². 2 ~1.0 g / m 2 Furthermore, the particle size of the temperature-sensitive plant essential oil microcapsules is 10 μm to 25 μm.

[0013] As can be seen from the above technical means, this application strictly controls the wet coating thickness within an extremely thin range of 8 μm to 10 μm, combined with a microcapsule particle size distribution of 10 μm to 25 μm. This ensures that single or multiple microcapsules can be completely embedded in the adhesive layer, avoiding the hardening, brittleness, and deterioration of the feel of the formed paper caused by excessive coating thickness, and effectively preventing mechanical compression damage to the microcapsule wall material caused by adhesive shrinkage during drying. Secondly, this application uses 0.8 g / m³ temperature-sensitive plant essential oil microcapsules. 2 ~1.0 g / m 2The unit area loading capacity, while meeting the essential oil slow-release concentration threshold during inhalation, can significantly reduce the risk of powder shedding and oil migration caused by excessive loading. Furthermore, the structure of this application imparts excellent air permeability retention to the forming paper. The microcapsule particle size is larger than the pore size of conventional forming paper. Combined with the limitations of the gravure micro-coating process, the adhesive will not penetrate and block the through pores inside the substrate. Thus, even after incorporating the temperature-sensitive controlled-release function, the air permeability of the original paper within a wide range of 2000 CU to 10000 CU is still fully preserved, ensuring stable filter rod draw resistance and fully meeting the requirements of existing high-speed cigarette rolling processes.

[0014] Furthermore, the food-grade aliphatic phase change material is selected from deodorized low-melting-point paraffin-beeswax compound, food-grade palm wax-gelatin compound, glyceryl monostearate, refined rice bran wax compound, and high-purity C. 20 -C 22 One or more of straight-chain alkanes and food-grade hydrogenated vegetable oil esters.

[0015] Furthermore, the porous carrier is selected from food-grade porous starch and / or porous cellulose.

[0016] Furthermore, after the substrate is coated and dried with a functional thin coating, its surface retains several through-holes for air permeability, and its air permeability is 2000 CU~10000 CU.

[0017] A second aspect of this invention provides a method for preparing a thermally responsive flue gas gain filter rod forming paper, comprising the following steps:

[0018] (1) Using plant essential oil as the core material and food-grade aliphatic phase change material with a phase change temperature of 40℃~50℃ as the phase change wall material, temperature-sensitive plant essential oil microcapsules were prepared.

[0019] (2) Add the thermosensitive plant essential oil microcapsules, porous carrier, coating solution and dispersant to deionized water, stir, and prepare the functional coating solution;

[0020] (3) A thin coating is applied to the inner surface of the filter rod forming paper substrate in contact with the cellulose acetate bundle using a gravure micro-coating process. After coating, the paper is then subjected to low-temperature gradient drying, static elimination and winding in sequence to prepare a thermally responsive flue gas gain filter rod forming paper.

[0021] As can be seen from the above technical means, this application adopts an inner single-sided gravure micro-coating process, which can not only accurately place the functional thin coating in the mainstream flue gas channel to maximize the gain effect, but also avoid the negative impact on the air permeability of the formed paper. Combined with the low temperature gradient drying process, the temperature is controlled below the phase change threshold of the wall material throughout the process. While ensuring the curing of the adhesive layer and the moisture content meet the standards, the risk of thermal damage to the temperature-sensitive plant essential oil microcapsules is eliminated. Moreover, the entire process is compatible with existing cigarette papermaking production lines, and has excellent industrialization and promotion value.

[0022] Furthermore, in step (1), the mass ratio of the core material to the phase change wall material is 1:(1.2~1.8).

[0023] Furthermore, in step (2), the functional coating liquid consists of the following components in parts by mass:

[0024] The composition consists of 7-8 parts of thermosensitive plant essential oil microcapsules, 0.3-0.5 parts of porous carrier, 12-15 parts of coating adhesive, 0.3-0.5 parts of dispersant, and 76-81 parts of deionized water.

[0025] Furthermore, step (3) also includes:

[0026] Before coating, the filter rod forming paper substrate is placed in a constant temperature and humidity environment of 22℃~24℃ and 50%~60% for 24 hours to eliminate the internal stress of the substrate.

[0027] The low-temperature gradient drying process includes: first, infrared radiation heating at 38℃~40℃ for 65s~75s; then, dehumidification treatment at 25℃~28℃ and negative pressure of -0.02 MPa~ -0.03 MPa for 30s~35s, controlling the moisture content of the finished product to 7%~8%.

[0028] As can be seen from the above technical means, this application adopts a combined drying process of infrared low-temperature radiation and room temperature negative pressure dehumidification. There is no hot air blowing or localized overheating throughout the process, and the core temperature is controlled at 38℃~40℃, which is lower than the phase change failure temperature of the temperature-sensitive plant essential oil microcapsule wall material. The total drying time is 1.5 min~1.8 min. Combined with ultra-thin coating and high-solids content coating adhesive, the moisture content of the finished product can be stabilized at 7%~8%. There is no microcapsule breakage or powder shedding during the drying process, the adhesive layer is firmly bonded, the paper surface is soft, and the air permeability and winding performance of the base paper remain unchanged.

[0029] A third aspect of the present invention provides an application of a thermally responsive flue gas gain filter rod forming paper, wherein the thermally responsive flue gas gain filter rod forming paper is used to roll a cellulose acetate filter rod, wherein the thermally responsive flue gas gain filter rod forming paper is the aforementioned thermally responsive flue gas gain filter rod forming paper, or is prepared by the aforementioned preparation method.

[0030] According to the above technical means, the rolled cellulose acetate filter rod prepared in this application has a filter rod forming paper temperature of 40℃~50℃ during suction, reaching the phase change temperature of the wall material. The microcapsules automatically melt and break open, slowly releasing plant essential oils, which moisten the smoke, reduce impurities, relieve throat irritation, and achieve the effect of enhancing the smoke.

[0031] The beneficial technical effects of this invention are as follows:

[0032] The temperature-sensitive plant essential oil microcapsules prepared by this invention are stable and leak-proof under room temperature and drying conditions. When heated to 45℃~55℃ during inhalation, the capsules precisely rupture and release aroma, which can soften the smoke, reduce irritation, improve off-flavors, and enhance the aftertaste. The heat-responsive smoke-enhancing filter rod forming paper prepared by this invention has stable physical properties, minimal air permeability fluctuations, does not shed powder, and does not clog pores, making it suitable for high-speed rolling and long-term storage. Compared with traditional flavoring methods, this invention achieves an integrated effect of simultaneous aroma release during inhalation, smoke enhancement, and long-term stable function, significantly improving the sensory quality of low-tar, high-filtration cigarettes and possessing good prospects for industrial application. It also effectively solves industry pain points such as uncontrollable release, poor room temperature stability, easy pore clogging, easy oil migration and separation, and limited functionality in existing technologies, comprehensively improving cigarette smoke quality and processing adaptability. Compared with existing tow-loaded aroma microcapsule solutions, the thin-coating process on the inner side of the forming paper in this invention does not clog the air permeability pores of the base paper, and the porous carrier anchoring system significantly extends the aroma retention time.

[0033] This invention selects food-grade aliphatic phase change material with a phase change temperature of 40℃~50℃ as the microcapsule wall material, precisely matching its phase change threshold with the actual temperature rise in the filter area during cigarette inhalation. At the moment of inhalation, the phase change wall material undergoes a physical phase change and melts, intelligently releasing the throat-soothing plant essential oils within the capsule, effectively moisturizing the smoke and reducing irritating impurities. In the non-inhalation state, it remains sealed, preventing ineffective volatilization of flavorings, significantly improving the utilization rate of functional components and the consistency of sensory experience, thereby achieving precise thermal response and high efficiency gains in smoke control.

[0034] This invention innovatively constructs a temperature-sensitive anchoring system, utilizing the microporous structure of food-grade porous starch and porous cellulose to provide physical adsorption sites and skeletal support for temperature-sensitive plant essential oil microcapsules. This improves the dispersion uniformity of microcapsules in the coating solution, enhances the adhesion of microcapsules to the surface of the forming paper, and effectively inhibits sedimentation, agglomeration, powdering, and migration. As a result, it significantly improves the dispersion stability of the functional coating solution and the structural strength of the finished product, ensuring the integrity of the functional components during storage and transportation.

[0035] This invention achieves a thin and breathable functional thin coating by strictly controlling the wet coating thickness to 8 μm~10 μm and using a food-grade coating adhesive with high solid content, moderate viscosity, and stable adhesion, combined with a specific low-temperature gradient drying process. The preparation method of this application does not clog the original pore structure of the filter rod forming paper, and the finished product's air permeability remains within a wide range of 2000 CU~10000 CU, fully complying with the YC / T 263 industry standard. It can cover the forming requirements of conventional, high-permeability, and special cigarette filter rods, has wide applicability and strong versatility, and avoids paper hardening and brittleness, fully preserving the original paper's feel and rolling processing characteristics.

[0036] This invention features a green and compatible process with a wide range of applications and ease of industrialization. The product is made from food-grade raw materials, is odorless and highly safe, and has good harmony with the natural aroma of tobacco. The overall process is mild and controllable, does not damage the properties of the base paper, requires no modification to existing production lines, and is compatible with substrates with a permeability range of 2000 CU to 10000 CU. It is suitable for various cigarette types, including regular, medium, and slim cigarettes, and has promising prospects for industrialization.

[0037] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Detailed Implementation

[0038] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should be understood that certain features of the invention (described in the context of separate embodiments for clarity) may also be provided in a single embodiment. Conversely, multiple features of the invention (described in the context of a single embodiment for brevity) may also be provided separately or in any suitable combination or, where appropriate, in any other described embodiment of the invention. Certain features described in the context of various embodiments will not be considered essential features of those embodiments unless the embodiment is inoperable without those elements. The invention is further illustrated below by specific examples; however, it should be noted that the specific process conditions and results described in the embodiments of the invention are merely illustrative and should not be construed as limiting the scope of protection of the invention. All equivalent changes or modifications made in accordance with the spirit and essence of the invention should be covered within the scope of protection of the invention.

[0039] This invention provides a thermally responsive flue gas gain filter rod forming paper, comprising a filter rod forming paper substrate and a functional thin coating applied to the inner surface of the substrate on the side facing the cellulose acetate bundle;

[0040] The functional thin coating includes an adhesive layer and a temperature-sensitive anchoring system dispersed and fixed in the adhesive layer. The temperature-sensitive anchoring system includes a porous carrier and temperature-sensitive plant essential oil microcapsules. The temperature-sensitive plant essential oil microcapsules are partially embedded in the micropores of the porous carrier or adsorbed on the surface of the porous carrier.

[0041] Among them, the thermosensitive plant essential oil microcapsule includes a plant essential oil core material and a phase change wall material that encapsulates the plant essential oil core material. The phase change wall material is a food-grade aliphatic phase change material with a phase change temperature of 40℃~50℃.

[0042] Furthermore, the porous carrier and the temperature-sensitive plant essential oil microcapsules of this application together constitute a temperature-sensitive anchoring system, which can effectively inhibit microcapsule migration, oil separation, and powder shedding; the phase change range of 40℃~50℃ is precisely matched with the temperature rise of the suction surface of the filter rod forming paper, and the wall material melts and releases essential oil only when the suction temperature rises, and the aroma is locked in the airtight container at room temperature, achieving synchronous gain of smoke.

[0043] Furthermore, the wet coating thickness of the functional thin coating is 8 μm to 10 μm, and the area loading of the temperature-sensitive plant essential oil microcapsules on the substrate in the dry state is 0.8 g / m². 2 ~1.0 g / m 2 Furthermore, the particle size of the temperature-sensitive plant essential oil microcapsules is 10 μm to 25 μm.

[0044] Furthermore, the food-grade aliphatic phase change material is selected from deodorized low-melting-point paraffin-beeswax compound, food-grade palm wax-gelatin compound, glyceryl monostearate, refined rice bran wax compound, and high-purity C. 20 -C 22 One or more of straight-chain alkanes and food-grade hydrogenated vegetable oil esters.

[0045] Furthermore, the porous carrier is selected from food-grade porous starch and / or porous cellulose.

[0046] Furthermore, after the substrate is coated and dried with a functional thin coating, its surface retains several through-holes for air permeability, and its air permeability is 2000 CU~10000 CU.

[0047] This invention also provides a method for preparing a thermally responsive flue gas gain filter rod forming paper, comprising the following steps:

[0048] (1) Using plant essential oil as the core material and food-grade aliphatic phase change material with a phase change temperature of 40℃~50℃ as the phase change wall material, temperature-sensitive plant essential oil microcapsules were prepared.

[0049] Specifically, the steps are detailed below:

[0050] The core material is made from natural plant essential oils that soothe the throat, reduce inflammation, and provide relief. It features single or blended essential oils such as oroxylum indicum, peppermint, honeysuckle, licorice, salvia miltiorrhiza, scutellaria barbata, and tea tree. The wall material is made from odorless, food-grade aliphatic phase change materials with a phase change temperature of 40℃~50℃. It features deodorized low-melting-point paraffin-beeswax blends, food-grade palm wax-gelatin blends, glyceryl monostearate, refined rice bran wax blends, and high-purity C. 20 -C 22 Straight-chain alkanes, food-grade hydrogenated vegetable oil esters, no industrial wax odor, phase change range adapted to the actual smoking temperature of filter rod forming paper, does not interfere with the sensory aroma of cigarettes.

[0051] In addition, this application adds 0.3% to 0.5% of a food-grade nonionic dispersant, preferably Tween-80 or Span-60, to prevent the system from stratifying and agglomerating, and to improve the encapsulation stability.

[0052] This application prepares materials with a core material to phase change wall material mass ratio of 1:(1.2~1.8). The wall material is heated to 60℃~80℃ and completely melted, then mixed with the core material and stirred to obtain a homogeneous oil phase. The dispersant is dissolved in deionized water at the same temperature to obtain an aqueous phase. The oil phase is slowly added dropwise to the aqueous phase at 2 mL / min~3 mL / min, emulsified at 500 r / min~800 r / min for 15 min~20 min, and homogenized under high pressure at 35 MPa~40 MPa 2~3 times. The wall material is then cooled to 25℃ at a rate of 3℃ / min~4℃ / min to solidify into capsules. After vacuum filtration, washing with deionized water 2~3 times, and vacuum drying at 35℃~40℃ and a vacuum degree of -0.07 MPa~-0.08 MPa for 10h~12h, temperature-sensitive plant essential oil microcapsules with a particle size of 10 μm~25 μm and an encapsulation rate of ≥75% are obtained.

[0053] (2) Add the temperature-sensitive plant essential oil microcapsules, porous carrier, coating solution and dispersant to deionized water, stir, and prepare the functional coating solution.

[0054] Specifically, the steps are detailed below:

[0055] The functional coating liquid of this application is composed of the following components in parts by weight:

[0056] The coating consists of 7-8 parts thermosensitive plant essential oil microcapsules, 0.3-0.5 parts porous carrier, 12-15 parts coating solution, 0.3-0.5 parts dispersant, and 76-81 parts deionized water. Preferably, the dispersant is food-grade Tween-80 or Span-60, whose core function is to reduce the surface tension of the system, break up microcapsule agglomerates, prevent microcapsules from settling and clumping in the coating solution, and improve the overall uniformity and flowability of the coating solution, ensuring the stability of subsequent coating processes. The porous carrier is selected from one or a combination of two food-grade porous starch and porous cellulose. Its surface and interior are rich in microporous structures, providing physical adsorption sites and skeletal support for the thermosensitive plant essential oil microcapsules, improving the dispersion uniformity of microcapsules in the coating solution, enhancing the adhesion of microcapsules to the surface of the formed paper, effectively inhibiting sedimentation, agglomeration, powdering, and migration. Together with the thermosensitive plant essential oil microcapsules, it constitutes a porous carrier anchoring + microcapsule controlled-release synergistic system. The coating adhesive is a food-grade, odorless vinyl acetate emulsion and hydroxypropyl methylcellulose adhesive. The solid content of the adhesive is controlled at 30%~45%, with moderate viscosity and stable adhesion. It is suitable for gravure micro-coating and thin-coating processes. By strictly controlling the coating thickness and coating amount, the microcapsules can be firmly fixed on the surface of the formed paper, eliminating the problems of powder shedding and migration during use. At the same time, it will not clog the pores of the 2000 CU~10000 CU wide range of breathable substrates, ensuring that the air permeability of the substrate is stable and meets the standards. After drying, the adhesive layer is thin and uniform, without the problem of paper surface hardening and brittleness, and fully retains the original paper's feel and rolling processing characteristics.

[0057] In preparing the functional coating solution of this application, deionized water is first added to a mixing tank and stirred at a low speed of 200 r / min to 300 r / min. A dispersant is added and stirred for 10 min until completely dissolved. Then, temperature-sensitive plant essential oil microcapsules are slowly added and stirred for another 15 min to break up the agglomerated particles. Next, a porous carrier is added, and finally, the coating adhesive is added at a uniform speed. The mixture is stirred at a constant temperature of 25℃ to 30℃ for 20 min to 25 min until the system is homogeneous. Temperature is controlled throughout the process to prevent the microcapsule wall material from softening and breaking, thus obtaining a functional coating solution that is uniformly dispersed, free of sediment and agglomeration, and with flowability suitable for the coating process.

[0058] (3) A thin coating is applied to the inner surface of the filter rod forming paper substrate in contact with the cellulose acetate bundle using a gravure micro-coating process. After coating, the paper is then subjected to low-temperature gradient drying, static elimination and winding in sequence to prepare a thermally responsive flue gas gain filter rod forming paper.

[0059] Specifically, the steps are detailed below:

[0060] The filter rod forming paper substrate of this application is made of cigarette filter rod forming paper that conforms to the YC / T 263 industry standard, and the core physicochemical index range is: basis weight 26 g / m³. 2 ~36 g / m 2With an air permeability of 2000 CU to 10000 CU, an initial moisture content of 7% to 9%, and a longitudinal tensile strength ≥1.2 kN / m, the paper surface is smooth and free of defects, lint, and dust. Before use, the substrate is placed in a constant temperature and humidity environment (temperature 22℃ to 24℃, relative humidity 50% to 60%) for more than 24 hours to eliminate internal stress generated during production and storage, ensuring uniform coating and stability in subsequent rolling processes. This wide range of air permeability can cover the molding requirements of conventional, high-permeability, and special cigarette filter rods, making it suitable for a wide range of scenarios and highly versatile.

[0061] This application employs a gravure microcoating process to perform a single-sided thin coating on the inner surface of the filter rod forming paper substrate in contact with the cellulose acetate bundle, adapting to the characteristics of coating solutions with a solid content of 30%~45%; the anilox roller line count is 120~150 lines / inch, the coating speed is 10 m / min~13 m / min, the wet coating thickness is strictly controlled within 8 μm~10 μm, and the microcapsule unit area loading is consistently maintained at 0.8 g / m². 2 ~1.0 g / m 2 The coating pressure is set to a moderate and gentle mode to avoid excessive pressure that could lead to excessive penetration of the adhesive or damage to the microcapsules. The entire coating process is monitored in real time to ensure that the paper surface is uniform, without any missed coating, drips, or local accumulation. This eliminates the risk of clogging from the process end and ensures the uniform dispersion of the microcapsules and the uniform and stable release of fragrance from the filter rod.

[0062] This application employs a combined drying process of infrared low-temperature radiation and room-temperature negative pressure dehumidification. The entire process involves no hot air blowing and no localized overheating, with the core temperature controlled at 38℃~40℃, below the phase change failure temperature of the temperature-sensitive plant essential oil microcapsule wall material. After coating, the substrate enters a sealed drying channel at a uniform speed, first undergoing infrared radiation heating at 38℃~40℃ for 65s~75s for gentle dehydration from the inside out; then it enters a dehumidification section at 25℃~28℃ and negative pressure of -0.02 MPa~-0.03 MPa for 30s~35s to remove moisture and cure the adhesive layer. The total drying time is 1.5 min~1.8 min. Combined with ultra-thin coating and high-solids-content coating adhesive, the finished product's moisture content can be stabilized at 7%~8%. The drying process is free of microcapsule breakage and powder shedding, resulting in strong adhesive adhesion, a soft paper surface, and unchanged air permeability and winding performance of the base paper.

[0063] After drying, the forming paper is subjected to electrostatic elimination treatment to eliminate the accumulation of static electricity on the paper surface and the coating layer, and to prevent adsorption and adhesion, dust adsorption and paper wrinkling during the winding process; then it is wound smoothly with constant tension, and the winding tightness is controlled to be uniform and moderate to avoid loose winding, curling edges and interlayer misalignment, and finally the thermal response flue gas gain filter rod forming paper is obtained.

[0064] The present invention also provides an application of a thermally responsive flue gas gain filter rod forming paper, wherein the thermally responsive flue gas gain filter rod forming paper is used to roll a cellulose acetate filter rod, wherein the thermally responsive flue gas gain filter rod forming paper is the aforementioned thermally responsive flue gas gain filter rod forming paper, or is prepared by the aforementioned preparation method.

[0065] Furthermore, this application uses the aforementioned thermally responsive smoke-enhancing filter rod forming paper to roll cellulose acetate filter rods. The filter rod specifications are a diameter of 5.4 mm to 7.8 mm, a length of 100 mm to 120 mm, and a hardness of ≥85%. The functional filter rods are rolled and combined with tobacco segments to produce standard cigarettes with a total length of 84 mm to 97 mm. When smoking, the temperature of the filter rod forming paper rises to 40℃ to 50℃, reaching the phase change temperature of the wall material. The microcapsules automatically melt and break open, releasing plant essential oils in a slow-release manner, which moistens the smoke, reduces impurities, and relieves throat irritation, thus achieving the smoke-enhancing effect. It is compatible with existing cigarette production processes and adapts to the filter rod forming requirements with a permeability range of 2000 CU to 10000 CU, demonstrating excellent industrial adaptability.

[0066] The present invention will be described in detail below through specific examples and embodiments. It should also be understood that the following embodiments are only for specific illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below.

[0067] Example 1

[0068] (1) Prepare materials with a mass ratio of core material to phase change wall material of 1:1.5. Select honeysuckle essential oil and licorice essential oil with a mass ratio of 1:1 as core material and deodorized low melting point paraffin-beeswax compound with a phase change temperature of 47℃~48℃ as wall material. Heat the wall material to 64℃ to melt, add the core material and stir to obtain oil phase. Dissolve Tween-80, which accounts for 0.4% of the total mass of the system, in deionized water to obtain aqueous phase. Add the oil phase to the aqueous phase at 2.5 mL / min, emulsify at 750 r / min for 18 min, and homogenize twice under high pressure of 38 MPa. Cool to 25℃ at 3℃ / min to solidify into capsules. Vacuum filter and wash with deionized water 3 times. Vacuum dry at 38℃ and -0.075 MPa for 11 h, pass through a 25μm sieve to obtain temperature-sensitive plant essential oil microcapsules with a particle size of 10 μm~25 μm and an encapsulation rate of ≥75%.

[0069] (2) Select a quantitative dose of 30 g / m 2Cigarette filter rod forming paper with an air permeability of 5000 CU and an initial moisture content of 8% was placed at 23℃ and 55% relative humidity for 24 hours to equilibrate and obtain filter rod forming paper substrate.

[0070] Weigh out 7.5 parts of thermosensitive plant essential oil microcapsules, 13 parts of food-grade vinyl acetate emulsion, 0.5 parts of porous cellulose, 0.4 parts of Tween-80, and 78.6 parts of deionized water. First, add the deionized water, then add Tween-80 while stirring at a low speed of 250 r / min and stir for 10 min until dissolved. Slowly add the thermosensitive plant essential oil microcapsules and stir for 15 min to break up any agglomerates. Add the porous cellulose. Finally, add the food-grade vinyl acetate emulsion at a uniform speed and stir at a constant temperature of 28℃ for 22 min until homogeneous. The temperature should not exceed 30℃ throughout the process to obtain a functional coating solution with a solid content of 33%.

[0071] (3) A single-sided thin coating was applied to the inner surface of the filter rod forming paper substrate in contact with the cellulose acetate bundle using a gravure microcoating process; the anilox roller was 130 lines / inch, the coating speed was 12 m / min, the wet coating thickness was 9 μm, and the microcapsule unit area loading was stable at 0.85 g / m². 2 The coating pressure is set to a gentle mode to avoid microcapsule damage; the entire process is monitored to ensure no missed coating, no dripping, no accumulation, and no clogging.

[0072] The drying process combines infrared low-temperature radiation with room temperature negative pressure dehumidification. The product is first heated by infrared radiation at 39℃ for 70 seconds, and then dehumidified at 26℃ and -0.025 MPa negative pressure for 32 seconds, for a total duration of 1.7 minutes.

[0073] After drying, static electricity is eliminated, and the paper is wound up smoothly with constant tension to obtain thermally responsive flue gas gain filter rod forming paper.

[0074] Example 2

[0075] The difference between this embodiment and Embodiment 1 is that:

[0076] (1) Prepare materials with a mass ratio of core material to phase change wall material of 1:1.3. Select peppermint oil and wintergreen oil with a mass ratio of 1:1 as core material and glyceryl monostearate with a phase change temperature of 48℃~49℃ as wall material.

[0077] (2) Select a quantitative dose of 28 g / m 2 Highly permeable filter rod forming paper with an air permeability of 10000 CU and an initial moisture content of 7.5% was placed at 23℃ and 55% relative humidity for 24 hours to equilibrate, thus obtaining the filter rod forming paper substrate.

[0078] (3) In the functional coating solution, the dispersant was Span-60, with an addition amount of 0.35 parts; the porous carrier was porous starch. The solid content of the functional coating solution was 32%, and the microcapsule loading per unit area was consistently 0.8 g / m². 2 .

[0079] Example 3

[0080] The difference between this embodiment and Embodiment 1 is that:

[0081] (1) Prepare materials with a mass ratio of core material to phase change wall material of 1:1.7. Select honeysuckle essential oil and peppermint essential oil with a mass ratio of 1:1 as core material and food-grade hydrogenated vegetable oil ester with a phase change temperature of 45℃~48℃ as wall material.

[0082] (2) Select a quantitative dose of 32 g / m 2 Filter rod forming paper with an air permeability of 3000 CU and an initial moisture content of 8.0% was placed at 23℃ and 55% relative humidity for 24 hours to equilibrate and obtain filter rod forming paper substrate.

[0083] The functional coating solution contains 8.0 parts of thermosensitive plant essential oil microcapsules, 15 parts of food-grade vinyl acetate emulsion, 0.5 parts of porous starch, 0.5 parts of Tween-80, and 76.5 parts of deionized water.

[0084] (3) The anilox roller has a speed of 120 lines / inch, a coating speed of 11 m / min, a wet coating thickness of 10 μm, and the microcapsule load per unit area is consistently maintained at 0.95 g / m². 2 ;

[0085] It adopts a combined drying process of infrared low-temperature radiation and room temperature negative pressure dehumidification, without using high-temperature hot air.

[0086] Comparative Example 1

[0087] The difference between this comparative example and Example 1 is that the blank control filter rod forming paper is not coated with microcapsules, and only the forming paper of the same specification is subjected to constant temperature and humidity equilibrium treatment.

[0088] Comparative Example 2

[0089] The difference between this comparative example and Example 1 is that only the microcapsule wall material is replaced with ordinary paraffin wax with a phase change temperature of 55°C to 60°C, while the other raw materials and processes are completely the same.

[0090] Comparative Example 3

[0091] The difference between this comparative example and Example 1 is that the microcapsules are replaced with an equal amount of honeysuckle and licorice compound essential oil, which is directly added to the coating solution without microcapsule encapsulation.

[0092] Comparative Example 4

[0093] The difference between this comparative example and Example 1 is that the liquid-solid content of the functional coating is increased to 60%, the wet coating thickness is increased to 15 μm, and the amount of adhesive used is increased.

[0094] Comparative Example 5

[0095] The difference between this comparative example and Example 1 is that porous cellulose / porous starch is not added to the functional coating solution.

[0096] Performance testing

[0097] The effect of storage time on microcapsule stability: To verify the storage, heat resistance, and mechanical stability of temperature-sensitive plant essential oil microcapsules, this application conducted three stability verification tests on the microcapsule samples prepared in Example 1. The test environment was uniformly set at a temperature of 22℃~24℃ and a relative humidity of 50%~60%, focusing on verifying the stability during the conventional 6-month storage period in the cigarette industry and throughout the entire processing. The specific test methods are as follows:

[0098] The prepared microcapsules were sealed and placed in the test environment. Samples were taken monthly for six consecutive months. The retention rate of the essential oil in the core material was detected by gas chromatography. The appearance of the microcapsules, the presence of clumping, fragrance leakage, and odor leakage were observed simultaneously. The test results are shown in Table 1.

[0099] Table 1. Effect of storage time on microcapsule stability

[0100]

[0101] As shown in Table 1, the temperature-sensitive plant essential oil microcapsule sample prepared in Example 1 of this application showed a slow, month-by-month decrease in essential oil retention rate after a 6-month storage period. Although there was a slight decrease, the overall retention rate remained at a relatively high level of over 91%, indicating that the microcapsules possess good long-term storage stability. Simultaneous observation showed that throughout the entire storage period, the microcapsule particles remained intact, without clumping, wall material cracking, essential oil evaporation or leakage, or the generation of unpleasant odors. All physicochemical and sensory indicators fully met the storage and use requirements for cigarette materials with a 6-month shelf life. This result fully verifies the effectiveness of the emulsification-cooling solidification process and the food-grade aliphatic phase change material wall material used in this application in ensuring the essential oil retention rate and structural integrity of the core material.

[0102] Physical property testing of the formed paper: The key physical properties of the suction-responsive flue gas warming and anti-sting filter rod formed paper prepared in each embodiment and comparative example were systematically tested. The main focus was on the basis weight, moisture content, tensile strength, air permeability, dust loss rate, essential oil loading and storage stability, etc. The processing adaptability and functional stability of the products were comprehensively evaluated. The test results are shown in Table 2.

[0103] Table 2. Test results of physical properties of filter rod forming paper in each embodiment and comparative example.

[0104]

[0105] As shown in Table 2, the quantitative values ​​of Examples 1-3 of this application are 30.8 g / m³, respectively. 2 28.5 g / m 2 32.6 g / m 2 The basis weight is slightly increased compared to the base paper, which is consistent with the objective law of slight weight gain after gravure micro-coating and thin coating; the moisture content is controlled at 7.0%~7.6%, which matches the gradient low-temperature drying process, and the paper surface is soft and not brittle; the longitudinal tensile strength is 1.4~1.6 kN / m and the transverse tensile strength is 0.6~0.7 kN / m, which can meet the strength requirements of filter rod forming and cigarette rolling; the air permeability matches the base paper reference height, which is 4960 CU in Example 1, 9940 CU in Example 2, and 2980 CU in Example 3, with air permeability fluctuations of ≤1.2%, indicating that the ultra-thin and soft coating will not clog the pores of the substrate and the air permeability is stable; the dust loss rate is ≤0.17%, indicating that the porous carrier and coating adhesive can firmly anchor the microcapsules to the inside of the formed paper without the risk of falling off and shedding dust; the essential oil loading is 61.3~83.5%. μg / g, the essential oil retention rate is ≥91.7% after 6 months of storage at room temperature, demonstrating the excellent stability of microcapsule encapsulation and room temperature storage.

[0106] Comparative Example 1 was a blank uncoated formed paper with no essential oil loading, and all other indicators were consistent with the substrate. Comparative Example 2 used a wall material with a relatively high phase change temperature (55℃~60℃). Due to the poor matching between the wall material and the system, the dispersion stability of the microcapsules decreased, resulting in a lower effective loading of essential oil and a slightly higher powder loss rate than the example. Comparative Example 3 did not use microcapsule encapsulation, and the direct addition of essential oil was volatile and prone to migration, resulting in a significantly lower 6-month retention rate. Comparative Example 4 used a high solids content and thick coating, which caused a large amount of adhesive to clog the pores and make the paper brittle, resulting in a sharp drop in air permeability, poor strength, and a significant increase in powder loss rate. Comparative Example 5 did not add a porous carrier, resulting in a decrease in the dispersion and adhesion of microcapsules, an increase in powder loss rate to 0.70%, and a decrease in the 6-month retention rate of essential oil of more than 20%, which proves that the porous carrier anchoring system has a significant synergistic effect on the stable loading of microcapsules.

[0107] Overall, this application demonstrates that, through the synergistic process of gentle gravure microcoating on the inner side, porous carrier anchoring, and low-temperature gradient drying, it can achieve efficient loading and long-term functional stability of microcapsules while ensuring the stability of the physical properties of the formed paper. Its comprehensive performance is significantly better than that of the comparative examples.

[0108] Sensory quality evaluation: Filter rods were prepared using the filter rod forming paper prepared in the above embodiments and comparative examples as raw materials. Based on slim cigarettes (cigarette length 97mm, circumference 17mm, filter length 30mm), the same series of filter rod samples were prepared on the same machine. Based on the slim cigarettes in production, the same series of slim cigarette samples were rolled on the same machine using the above-mentioned filter rods and the same type of tobacco, and sensory evaluation was conducted. The evaluation results are shown in Table 3.

[0109] Table 3 Sensory evaluation results

[0110]

[0111] As shown in Table 3, the total sensory scores of Examples 1-3 of this application ranged from 42.9 to 44.4, with each indicator score significantly higher than the comparative example, indicating excellent overall sensory quality. In the examples, the temperature-sensitive plant essential oil microcapsules can precisely trigger aroma release at the inhalation temperature. The released natural plant essential oils can effectively moisten the smoke, reduce irritation, improve off-flavors, and enhance the comfort of the aftertaste, resulting in a full and harmonious aroma and a smooth and gentle inhalation.

[0112] Comparative Example 1 was a blank unflavored forming paper, lacking the functions of warming the smoke, reducing irritation, enhancing aroma, and releasing fragrance. The smoke performance was bland and the aroma concentration was insufficient, but it still maintained the normal sensory level of conventional cigarettes, with a total score of 36.4. Comparative Example 2, due to the high phase transition temperature of the microcapsules, had difficulty effectively triggering aroma release during the smoking process, and the aroma enhancement effect was not obvious. Its sensory performance was similar to the blank group. Comparative Example 3 did not use microcapsule coating, so the essential oils were easily volatile and released unevenly, resulting in poor aroma coordination and stability, and a score lower than the blank group. Comparative Example 4, due to the high solids content and thick coating, caused pore blockage and paper brittleness, resulting in poor smoke permeability and a significant increase in off-flavors and irritation, and had the lowest sensory score. Comparative Example 5 did not add a porous carrier, so the dispersion and adhesion stability of the microcapsules decreased, the aroma release uniformity was insufficient, and its sensory performance was slightly lower than the examples and close to the blank group.

[0113] Overall, this application demonstrates that through the synergistic effect of temperature-sensitive aroma release, porous carrier anchoring, and gentle inner coating, it can significantly improve the sensory quality of cigarettes, with effects that are significantly better than those of blank paper and the comparative process.

[0114] In summary, this application demonstrates precise and stable temperature-sensitive controlled release, with physical properties meeting industry standards. Through internal gravure micro-coating, porous carrier anchoring, and low-temperature gradient drying processes, the resulting paper achieves basis weight, moisture content, tensile strength, and other indicators that meet the requirements of YC / T 263, with air permeability fluctuation ≤1.2%, no powder shedding, and no pore clogging. The essential oil loading reaches 61.3 μg / g~83.5 μg / g, with a retention rate ≥91.7% at room temperature for 6 months. This effectively solves the problems of easy volatility, uncontrollable release, and easy migration and separation of natural essential oils, demonstrating excellent processing and storage stability.

[0115] This application demonstrates outstanding smoke enhancement and significantly improved sensory quality. The temperature-sensitive plant essential oil microcapsules prepared in this application can precisely break open and release aroma at the smoking temperature, effectively improving the richness and harmony of the smoke aroma, reducing off-flavors and irritation, and optimizing the aftertaste comfort. Sensory evaluation shows that the total score reaches 42.9~44.4 points, significantly higher than the blank control and each comparison ratio, and can significantly improve the sensory performance of low-tar, high-filtration cigarettes.

[0116] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A thermally responsive flue gas gain filter rod forming paper, characterized in that, The invention includes a filter rod forming paper substrate and a functional thin coating applied to the inner surface of the substrate on the side facing the cellulose acetate bundle. The functional thin coating includes an adhesive layer and a temperature-sensitive anchoring system dispersed and fixed in the adhesive layer. The temperature-sensitive anchoring system includes a porous carrier and temperature-sensitive plant essential oil microcapsules. The temperature-sensitive plant essential oil microcapsules are partially embedded in the micropores of the porous carrier or physically adsorbed onto the outer surface of the porous carrier, and the temperature-sensitive plant essential oil microcapsules are constrained by the porous carrier skeleton. The temperature-sensitive plant essential oil microcapsule includes a plant essential oil core material and a phase change wall material covering the plant essential oil core material. The phase change wall material is a food-grade aliphatic phase change material with a phase change temperature of 40℃~50℃.

2. The thermally responsive flue gas gain filter rod forming paper according to claim 1, characterized in that, The wet coating thickness of the functional thin coating is 8 μm to 10 μm, and the dry loading of the temperature-sensitive plant essential oil microcapsules on the substrate is 0.8 g / m². 2 ~1.0 g / m 2 Furthermore, the particle size of the temperature-sensitive plant essential oil microcapsules is 10 μm to 25 μm.

3. The thermally responsive flue gas gain filter rod forming paper according to claim 1, characterized in that, The food-grade aliphatic phase change material is selected from deodorized low-melting-point paraffin-beeswax compound, food-grade palm wax-gelatin compound, glyceryl monostearate, refined rice bran wax compound, and high-purity C. 20 -C 22 One or more of straight-chain alkanes and food-grade hydrogenated vegetable oil esters.

4. The thermally responsive flue gas gain filter rod forming paper according to claim 1, characterized in that, The porous carrier is selected from food-grade porous starch and / or porous cellulose.

5. The thermally responsive flue gas gain filter rod forming paper according to claim 1, characterized in that, After the substrate is coated and dried with the functional thin coating, its surface retains several through-holes for air permeability, and its air permeability is 2000 CU~10000 CU.

6. A method for preparing a thermally responsive flue gas gain filter rod forming paper, characterized in that, Includes the following steps: (1) Using plant essential oil as the core material and food-grade aliphatic phase change material with a phase change temperature of 40℃~50℃ as the phase change wall material, temperature-sensitive plant essential oil microcapsules were prepared. (2) Add the temperature-sensitive plant essential oil microcapsules, porous carrier, coating solution and dispersant to deionized water, stir, and prepare functional coating solution; (3) A thin coating is applied to the inner surface of the filter rod forming paper substrate in contact with the cellulose acetate bundle using a gravure micro-coating process. After coating, the paper is then subjected to low-temperature gradient drying, static elimination and winding in sequence to prepare a thermally responsive flue gas gain filter rod forming paper.

7. The preparation method according to claim 6, characterized in that, In step (1), the mass ratio of the core material to the phase change wall material is 1:(1.2~1.8).

8. The preparation method according to claim 6, characterized in that, In step (2), the functional coating liquid is composed of the following components in parts by mass: The thermosensitive plant essential oil microcapsules consist of 7-8 parts, the porous carrier consists of 0.3-0.5 parts, the coating adhesive consists of 12-15 parts, the dispersant consists of 0.3-0.5 parts, and the deionized water consists of 76-81 parts.

9. The preparation method according to claim 6, characterized in that, Step (3) further includes: Before coating, the filter rod forming paper substrate is placed in a constant temperature and humidity environment of 22℃~24℃ and 50%~60% for 24 hours to eliminate the internal stress of the substrate. The low-temperature gradient drying process includes: first, infrared radiation heating at 38℃~40℃ for 65s~75s; then, dehumidification treatment at 25℃~28℃ and negative pressure of -0.02 MPa~ -0.03 MPa for 30s~35s, controlling the moisture content of the finished product to 7%~8%.

10. An application of a thermally responsive flue gas gain filter rod forming paper, characterized in that, The thermally responsive flue gas gain filter rod forming paper is used to roll cellulose acetate filter rods, wherein the thermally responsive flue gas gain filter rod forming paper is the thermally responsive flue gas gain filter rod forming paper according to any one of claims 1 to 5, or is prepared by the preparation method according to any one of claims 6 to 9.

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