Bio-based waterproof composite lining paper for cigarette case and preparation method of bio-based waterproof composite lining paper

Abstract

The invention discloses bio-based waterproof composite lining paper for a cigarette case and a preparation method of the bio-based waterproof composite lining paper. The waterproof composite lining paper is of a multi-layer hot-pressing composite structure and comprises a surface layer, a core layer and a bottom layer; the core layer is connected between the surface layer and the bottom layer through an adhesive; the core layer comprises biological base paper and a biological waterproof agent, the biological base paper is a lignin modified material, and the biological waterproof agent comprises modified lignosulfonate, nano cellulose and vegetable wax, so that the waterproof composite lining paper is degradable. The lining paper for the cigarette case is formed by compounding three layers of biological base paper, a functional biological waterproof agent solution and a perfume solution are completely permeated into the paper by combining a paper dipping processing method, and compared with traditional coating, the lining paper effectively solves the problems of poor paper performance and discoloration, and has an aroma enhancement function at the same time. The traditional lining paper which is not environment-friendly, difficult to degrade, waterproof and poor in barrier property can be replaced, and a greener and sustainable solution is provided for the packaging industry.

Description

Technical Field

[0001] This invention belongs to the field of inner lining paper technology, specifically relating to a bio-based waterproof composite inner lining paper for cigarette boxes and its preparation method. Background Technology

[0002] Inner lining paper is paper used in cigarette box packaging. Placed inside the cigarette box, it protects the cigarettes inside. The inner lining paper provides some moisture protection and aroma retention, effectively preventing the cigarettes from becoming damp and losing their aroma. The inner lining paper needs to be soft and not easily torn, while also having a certain degree of stiffness to provide effective support for the outer packaging.

[0003] The inner lining paper used in existing cigarette packaging is mostly simple in structure, serving only a basic packaging function, and has poor waterproofing. Careless handling can easily cause water stains on the packaged cigarettes, rendering them unusable. Furthermore, the existing inner lining paper lacks antibacterial properties. Since a pack of cigarettes is not used up in one go, prolonged use inevitably leads to bacterial contamination on the cigarette surface, hindering practical application. Meanwhile, waterproof composite inner lining paper, flame-retardant inner lining paper, and flavored composite inner lining paper mainly achieve their desired effects by coating a base paper with a combination of biological waterproofing agents, flame retardants, and fragrances using rollers. However, because this only acts on the paper surface and the coating amount is small, its actual effectiveness is limited.

[0004] For example, patent document CN222845687U discloses a tobacco liner paper, comprising an inner liner paper roll, consisting of an aluminum foil layer, a waterproof membrane layer, a kraft paper layer, and a composite paper layer. The top of the aluminum foil layer is bonded to the waterproof membrane layer, the surface of the waterproof membrane layer is bonded to the kraft paper layer, and the surface of the kraft paper layer is bonded to the composite paper layer. This improves the waterproof performance and structural strength of the liner paper, effectively protecting the cigarettes inside the cigarette box. However, the aluminum foil layer and waterproof membrane layer of the cigarette paper are not environmentally friendly and are difficult to degrade.

[0005] Therefore, it is necessary to design an innovative, environmentally friendly, bio-waterproof composite inner liner paper—a new type of packaging material inner liner paper that combines bio-based materials, waterproof performance, and environmental protection characteristics. The aim is to replace traditional, non-environmentally friendly, non-degradable, and poorly barrier-resistant inner liner papers, providing the packaging industry with a greener and more sustainable solution. Summary of the Invention

[0006] The purpose of this invention is to design an innovative, environmentally friendly, bio-waterproof composite inner liner paper, a new type of packaging material inner liner paper that combines bio-based materials, waterproof performance, and environmental protection characteristics. It aims to replace traditional, non-environmentally friendly, and difficult-to-degrade inner liner papers with poor waterproof and barrier properties, providing the packaging industry with a greener and more sustainable solution.

[0007] To solve the above technical problems:

[0008] The present invention provides a bio-based waterproof composite liner paper for cigarette boxes. The waterproof composite liner paper has a multi-layer hot-pressed composite structure, including a surface layer, a core layer and a bottom layer.

[0009] Furthermore, the surface layer is disposed on top of the core layer and includes bio-based paper and adhesive, with the adhesive coated on one end of the bio-based paper near the core layer;

[0010] Furthermore, the core layer includes bio-based paper and bio-waterproofing agent, with the bio-based paper impregnated in bio-waterproofing agents of different concentration gradients to make the waterproof composite liner paper biodegradable;

[0011] Furthermore, the bottom layer is located below the core layer and includes bio-based paper and adhesive, with the adhesive applied to one end of the bio-based paper near the core layer.

[0012] Furthermore, the bio-based paper is a lignin-modified material, which is a lignin-polylactic acid block copolymer, including lignin fibers and polylactic acid.

[0013] Furthermore, lignin fibers include one or more combinations of cellulose, hemicellulose, and lignin.

[0014] Furthermore, polylactic acid is polymerized from L-lactic acid or D-lactic acid monomers.

[0015] Furthermore, bio-waterproofing agents include modified lignin sulfonates, nanocellulose, and plant waxes.

[0016] Furthermore, for every 100 parts of the bio-waterproofing agent, it includes:

[0017] 45-55 parts of modified lignin sulfonate;

[0018] 15-20 parts of nanofibers;

[0019] 8-10 parts of plant wax;

[0020] And 10-15 parts pure water.

[0021] Furthermore, the bio-based paper is sequentially impregnated in at least three concentration gradients of bio-waterproofing agent, such that the penetration depth of the bio-waterproofing agent is at least 80% of the diameter of the bio-based paper fibers; the impregnation temperature for each concentration gradient of bio-waterproofing agent is 25℃~28℃, and the impregnation time for each concentration gradient of bio-waterproofing agent is 20~30s.

[0022] Furthermore, the concentration gradient of the bio-waterproofing agent impregnation is 60% to 80% of the original concentration.

[0023] Furthermore, the adhesive is a water-based adhesive, and 100 parts of the water-based adhesive include:

[0024] 30-35 parts of vinyl acetate;

[0025] 12-15 parts of polyvinyl alcohol;

[0026] 50-55 parts soft water;

[0027] 8-10 parts of ammonium persulfate;

[0028] And 0.01 to 0.02 parts of defoamer.

[0029] Optionally, the waterborne adhesive includes a waterborne resin, a cosolvent, and a defoamer, wherein the waterborne resin is selected from one or more combinations of water-soluble phenolic resin, amino resin, alkyd resin, epoxy resin, and acrylic resin; the cosolvent is selected from one or more combinations of isopropanol, n-butanol, ethylene glycol ether, and propylene glycol ether; and the defoamer is selected from one or more combinations of fluorinated modified silicone, n-octanol, or alcohol.

[0030] Furthermore, the coating amount of the water-based adhesive is 2.0–3.0 g / m². 2 3.0~4.0g / m 2 Or 4.0~5.5g / m 2 .

[0031] Furthermore, the core layer also includes a fragrance agent selected from one or more of the following: cherry, strawberry, bitter orange, apple powder, pear, mint, kudzu root, clove, sandalwood, rose, lotus leaf, chrysanthemum, jasmine, dried tangerine peel, walnut shell, coffee, tea, agarwood, hawthorn, licorice, cocoa, wood ear fungus, lotus seed, and ginger.

[0032] Furthermore, the concentration gradients of the fragrance solvent impregnation were 20%, 25%, and 30% of the original concentration, respectively.

[0033] Another aspect of the present invention provides a method for preparing bio-based waterproof composite liner paper for cigarette boxes, comprising the following steps:

[0034] Step A: Place the two layers of bio-based paper into the first and second sizing devices that are symmetrically arranged, so that the paper feeding speed of the bio-based paper is uniform. Apply water-based adhesive to one side of the bio-based paper to obtain the top layer and the bottom layer.

[0035] Step B: The bio-based paper is first impregnated in bio-waterproofing agents of different concentration gradients, and after the first drying, it is impregnated in fragrance agents of different concentrations and dried a second time to obtain the core layer;

[0036] Step C: The surface layer, core layer and bottom layer are hot-pressed together and dried a third time to obtain waterproof composite inner lining paper.

[0037] Furthermore, the penetration depth of the bio-waterproofing agent and fragrance agent is at least 80% of the diameter of the bio-based paper fibers; the impregnation temperature for each concentration gradient of the bio-waterproofing agent is 25℃~28℃, and the impregnation time for each concentration gradient of the bio-waterproofing agent is 20~30s.

[0038] Furthermore, the hot-pressing composite pressure is 1.0–1.2 MPa, the temperature is 110–125 °C, the composite time is 10–13 s, and the ring compression strength retention rate is 85.0–87.5%.

[0039] Furthermore, both the first and second drying processes were carried out at 80–100°C for 3–8 seconds.

[0040] Furthermore, the third drying condition is to dry at 80–100°C for 6–15 seconds.

[0041] Optionally, the lignin fibers in the bio-based paper include bamboo fiber and wood pulp fiber. A certain ratio of bamboo fiber to wood pulp fiber can be used to give the waterproof composite liner paper a certain tensile strength. Bamboo fiber is a type of cellulose fiber extracted from naturally grown bamboo, and it is not easily damaged during the production of the waterproof composite liner paper.

[0042] Optionally, the bamboo fiber is prepared using papermaking-grade bamboo pulp with an average degree of polymerization greater than 1000 as raw material and employing a bamboo fiber preparation process well known to those skilled in the art.

[0043] Optionally, the wood pulp fiber is typically softwood pulp fiber and / or hardwood pulp fiber, such as, but not limited to, poplar pulp fiber, common poplar pulp fiber, fast-growing poplar pulp fiber, Masson pine pulp fiber, larch pulp fiber, red pine pulp fiber, spruce pulp fiber, birch pulp fiber, linden pulp fiber, eucalyptus pulp fiber, and maple pulp fiber. Preferably, the wood pulp fiber is selected from one or more of Masson pine pulp fiber, larch pulp fiber, spruce pulp fiber, birch pulp fiber, poplar pulp fiber, and maple pulp fiber. Wood pulp fiber has advantages such as high strength and high plasticity. The addition of wood pulp fiber is beneficial to improving the tensile strength of cigarette paper.

[0044] The weight ratio of bamboo fiber to wood pulp fiber can be any value between (0.1 to 10.0):1, such as (0.1 to 0.3):1, (0.9 to 1.8):1, (1.8 to 4.0):1 or (4.0 to 10.0):1.

[0045] The thickness of the waterproof composite liner paper can be any value between 0.05 and 0.40 mm, for example, 0.10 mm, 0.15 mm, 0.20 mm, 0.25 mm, 0.30 mm, or 0.35 mm. The basis weight of the waterproof composite liner paper can be 80–200 g / m². 2 Any value between these ranges, for example, 85g / m 2 90g / m 2 95g / m 2 100g / m 2 Or 150g / m 2 The density of the waterproof composite lining paper can be 0.7–1.2 mg / cm³. 3 Any value between these ranges, for example, 0.75 mg / cm³. 3 0.80 mg / cm 3 0.85 mg / cm 3 0.90 mg / cm 3 Or 1.0 mg / cm 3 The ratio of the mass of the waterproof composite liner paper to its specific surface area can be 0.06–0.20 mg / mm². 2 Any value between these ranges, for example, 0.08 mg / mm. 2 0.10 mg / mm 2 0.12 mg / mm 2 0.14 mg / mm 2 0.16 mg / mm 2 Or 0.18 mg / mm 2 The transverse tensile strength of the waterproof composite liner paper can be any value between 2.5 and 5.0 N / m, for example, it can also be 2.7 N / m, 3.0 N / m, 3.5 N / m, 4.0 N / m, or 4.5 N / m. The longitudinal tensile strength of the waterproof composite liner paper can be any value between 4.5 and 7.0 N / m, for example, it can also be 4.7 N / m, 5.0 N / m, 5.5 N / m, 6.0 N / m, or 6.5 N / m.

[0046] Therefore, it can be concluded that this invention provides an innovative, environmentally friendly, bio-waterproof composite liner paper and its manufacturing method. This cigarette box liner paper is composed of three layers of bio-based paper. The bio-based paper uses materials derived from renewable plant resources, such as cellulose and lignin, and possesses biodegradability and renewability. By combining a paper impregnation process, functional bio-waterproofing agent solutions and fragrance solutions are completely infiltrated into the paper. Compared with traditional coating methods, this effectively solves the problems of weak paper performance and discoloration, while also providing fragrance enhancement. It can replace traditional, non-environmentally friendly, and difficult-to-degrade liner papers with poor waterproof and barrier properties, providing a greener and more sustainable solution for the packaging industry. Attached Figure Description

[0047] The above description of the present invention and the following detailed embodiments will be better understood when read in conjunction with the accompanying drawings. It should be noted that the drawings are merely examples of the claimed technical solutions.

[0048] Figure 1 This is a schematic diagram of the structure of the waterproof inner lining paper of the present invention;

[0049] Figure 2 This is a flowchart illustrating the preparation process of the waterproof inner lining paper of the present invention.

[0050] The reference numerals in the attached figures are explained as follows:

[0051] Waterproof composite lining paper: 1;

[0052] Surface layer: 11;

[0053] Core layer: 12;

[0054] Bottom layer: 13; Detailed Implementation

[0055] The following detailed description of the features and advantages of the present invention is sufficient to enable any person skilled in the art to understand the technical content of the present invention and implement it accordingly. Furthermore, based on the specification, claims and drawings disclosed herein, those skilled in the art can easily understand the related objects and advantages of the present invention.

[0056] The invention will now be described with reference to the accompanying drawings, in which similar reference numerals denote similar elements. While specific structures and arrangements are discussed, it should be understood that this is done merely for illustrative purposes. Those skilled in the art will recognize that other structures and arrangements can be used without departing from the spirit and scope of the invention. It will be apparent to those skilled in the art that the invention can also be used in a variety of other applications.

[0057] In this specification and claims, several terms will be used, and unless otherwise indicated, these terms will be defined as having the following meanings: the terms “comprising” or “having” have the same meaning as “containing” as defined above, and also include other forms of the term, such as the gerund and singular forms in English, meaning including but not limited to, and not intended to exclude, for example, other elements, components, integers, or steps. The singular forms “a” and “the” include the corresponding plural forms. “At least one” means one or more, and “more than one” means two or more.

[0058] All other terms used herein for special definition are intended to have the general meaning understood by one of ordinary skill in the art, and in particular, meaning that one of ordinary skill in the art, upon reading the claims, specification and drawings of this patent, can directly and without doubt determine how the technical solution of this patent can be implemented.

[0059] Even if there are incomplete descriptions, omissions, or ambiguities in the grammar, words, punctuation, graphics, symbols, etc. of the claims, specification, and drawings of this patent, a person skilled in the art can still arrive at the only correct understanding by reading the claims, specification, and drawings as a whole without extensive reasoning or experimentation, and effectively exclude various incorrect interpretations that are not aimed at achieving the purpose of this patent.

[0060] It should be understood that although terms such as "inner surface," "outer surface," "upstream," and "downstream" may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. Without departing from the scope of this invention, a first position may also be referred to as a second position, and similarly, a second position may also be referred to as a first position. Thus, features defined as "upstream" and "downstream" may explicitly or implicitly include one or more of these features. "Upstream" refers to the end furthest from the consumer's mouth during suction, in the upstream direction of the consumer's suction direction, and "downstream" refers to the end closest to the consumer's mouth during suction, in the downstream direction of the consumer's suction direction.

[0061] Example

[0062] The specific steps of the preparation method of the waterproof composite liner paper in this embodiment are as follows:

[0063] S1. Preparation of bio-based paper

[0064] Bio-based paper is prepared by using a base film manufacturing process, in which raw materials are pretreated, formed, and wound up.

[0065] First, lignin fiber is made from natural wood (coniferous wood is an option). The raw material is first crushed and screened to obtain relatively pure lignin fiber.

[0066] Secondly, lignin fibers are immersed in a sodium hydroxide solution for neutralization and reacted at 60°C for 30 minutes to degrade the macromolecular structure of lignin, making it easier to mechanically process and improving its reactivity and processability. Further grinding yields lignin fiber pulp, which is then pressurized by a high-pressure pump and passed through a narrow gap at high speed, generating strong shear and impact forces. This gradually refines and separates the lignin fibers, forming nanoscale fibers. When mixed with waste paper fibers, these nanofibers intertwine and entangle, forming a complex three-dimensional network structure, thereby enhancing the mechanical properties and strength of the waste paper.

[0067] Then, the lignin fiber pulp is mixed with plasticizers and stabilizers to obtain a mixed pulp, which increases its adhesion and flexibility, effectively enhancing the strength of the paper. The mixed pulp is then mechanically treated by heating and pressurizing it through a single / twin screw extruder.

[0068] Next, mechanically treated lignin fibers and polylactic acid (optionally L-lactic acid monomer polymerized) are added to a mixing tank at a temperature of 30°C and a speed of 200 rpm / min for 24 hours to ensure complete homogenization. The slurry concentration is then adjusted to 3% to obtain a lignin-polylactic acid block polymer.

[0069] Finally, the stirred lignin-polylactic acid block polymer is evenly distributed in a headbox, and then cured and dehydrated by press rollers and drying section to obtain bio-based paper.

[0070] S2. Preparation of waterproof composite liner paper

[0071] like Figure 1 As shown, the waterproof composite inner lining paper 1 has a three-layer paper structure, consisting of a first layer, a second layer, and a third layer from top to bottom. The first layer is the surface layer 11, the second layer is the core layer 12, and the third layer is the bottom layer 13.

[0072] like Figure 2 The above describes the specific preparation method of the waterproof composite inner lining paper 1:

[0073] (1) Preparation of surface layer 11: The bio-based paper prepared in step S1 above is placed in the first sizing device. The first sizing device includes a first roller and a first sizing trough. The first roller includes a first auxiliary roller and a first roller. The first roller is located in the first sizing trough. The bio-based paper is located between the first auxiliary roller and the first roller. By turning on the first sizing device, the first auxiliary roller and the first roller cooperate to perform single-sided sizing, so that the side of the bio-based paper close to the core layer 12 is sizing with water-based adhesive to obtain surface layer 11.

[0074] The water-based adhesive comprises 30 parts vinyl acetate, 12 parts polyvinyl alcohol, 50 parts soft water, 8 parts ammonium persulfate, and 0.01 parts defoamer per 100 parts.

[0075] The dosage of water-based adhesive is 2.5 g / m³. 2 The original viscosity of the water-based adhesive is 5000 cps, and the viscosity on the machine is 500 cps.

[0076] (2) Preparation of core layer 12:

[0077] First, the bio-based paper prepared in step S1 is placed in a first impregnation device. The first impregnation device includes a first auxiliary impregnation roller, a first impregnation roller, and a first impregnation tank. There are two first auxiliary impregnation rollers, positioned upstream and downstream of the first impregnation roller, respectively. The first impregnation roller is located within the first impregnation tank, and the first auxiliary impregnation roller and the first impregnation roller form a "V" shape. At least three first impregnation tanks are arranged side-by-side. Each of the three first impregnation tanks contains a bio-waterproofing agent. Along the conveying direction of the bio-based paper, the concentration of the bio-waterproofing agent in the first impregnation tank increases gradually to avoid excessive fiber swelling leading to strength loss in the bio-based paper. Specifically, the concentration of the diluted bio-waterproofing agent is 60%, 70%, and 80% of the original concentration.

[0078] The biological waterproofing agent, in 100 parts, includes 60% modified lignin sulfonate (purchased from Wanbang Special Materials Co., Ltd.), 30% nanocellulose (purchased from Wanbang Special Materials Co., Ltd.), and 10% plant wax (purchased from Hunan Yingkun Ink Chemical Co., Ltd.).

[0079] By activating the first impregnation device, the first auxiliary impregnation roller rotates and conveys the bio-based paper to the first impregnation point. Through the linkage of the first impregnation roller, the bio-based paper is completely impregnated in the bio-waterproofing agent. The conditions for impregnating the bio-waterproofing agent are: impregnation at 25°C for 30 seconds at each concentration gradient, so that the penetration diameter of the bio-waterproofing agent reaches 80% of the fiber diameter in the bio-based paper.

[0080] Secondly, the bio-based paper impregnated with the bio-waterproofing agent is dried for the first time in an infrared-hot air combined drying system (purchased from Huazhou (Fujian) Machinery Co., Ltd., a multi-functional dry and wet lining paper laminating machine). The first drying condition is drying at 80℃ for 5 seconds.

[0081] Then, the bio-based paper, after being impregnated and dried with the bio-waterproofing agent, is placed again in the second impregnation device. The second impregnation device includes a second auxiliary impregnation roller, a second impregnation roller, and a second impregnation tank. There are two second auxiliary impregnation rollers, positioned upstream and downstream of the second impregnation roller, respectively. The second impregnation roller is located within the second impregnation tank, and the second auxiliary impregnation roller and the second impregnation roller form a "V" shape. At least three second impregnation tanks are arranged side-by-side, each containing a fragrance solvent. Along the conveying direction of the bio-based paper, the concentration of the fragrance solvent in the second impregnation tank increases gradually to prevent excessive fiber swelling and subsequent strength loss of the bio-based paper. Specifically, the concentrations of the fragrance solvent are 20%, 25%, and 30% of the original concentration, respectively. The fragrance solvent is a functional additive (purchased from Jiangsu Tiger Chemical Co., Ltd.).

[0082] Next, the bio-based paper impregnated with fragrance solvent is dried a second time using an infrared-hot air combined drying system. The second drying conditions are 80°C for 6 seconds.

[0083] (3) Preparation of the bottom layer 13: The bio-based paper prepared in step S1 above is placed in the third sizing device. The third sizing device is set in the same way as the first sizing device, that is, the first sizing device and the third sizing device are symmetrically arranged in space. The first sizing device and the third sizing device are started at the same time, and the paper feeding speed of the bio-based paper is uniform and consistent, so that the side of the bio-based paper close to the core layer 12 is sizing with water-based adhesive to obtain the bottom layer 13.

[0084] The water-based adhesive comprises 30 parts vinyl acetate, 12 parts polyvinyl alcohol, 50 parts soft water, 8 parts ammonium persulfate, and 0.01 parts defoamer per 100 parts.

[0085] The dosage of water-based adhesive is 2.5 g / m³. 2 The original viscosity of the water-based adhesive is 5000 cps, and the viscosity on the machine is 500 cps.

[0086] (4) Hot pressing lamination: The surface layer 11, core layer 12 and bottom layer 13 are laminated together by a hot pressing device (purchased from Huazhou (Fujian) Machinery Co., Ltd., a multi-functional laminating machine for dry and wet inner lining paper). The adhesive side of the surface layer 11 and the bottom layer 13 are hot pressed together with the core layer 12. The pressure of the hot pressing lamination is 1.2MPa, the temperature is 125℃, the lamination time is 12s, and the ring crush strength retention rate is 87.5%, resulting in a three-in-one hot pressing laminated paper.

[0087] The three-in-one hot-pressed composite paper is dried a third time using an infrared-hot air combined drying system. The third drying conditions are 80°C for 10 seconds to obtain waterproof composite inner lining paper, which is marked as inner lining paper #1.

[0088] Comparative Example 1

[0089] Compared to the comparative example, the inner lining paper in this example is commercially available 1916 medium-length cigarette box inner lining paper, labeled as inner lining paper &1.

[0090] Comparative Example 2

[0091] Compared with the comparative example, the core layer of the inner liner paper is not impregnated with a concentration gradient of biological waterproofing agent and fragrance solution. Instead, it is directly impregnated with a biological waterproofing agent with a concentration of 80% and a fragrance solution with a concentration of 75%, and the resulting inner liner paper for cigarette boxes is labeled as inner liner paper &2.

[0092] Comparative Example 3

[0093] Compared to the comparative example, the core layer of the inner lining paper in this example does not use a concentration gradient impregnation of biological waterproofing agent and fragrance solution. Instead, it is directly coated on both sides with a 70% concentration of biological waterproofing agent and a 75% concentration of fragrance solution, with a coating amount of 4.0 g / m². 2 The inner lining paper for cigarette boxes was prepared and marked as inner lining paper &3.

[0094] Test Example 1: Hydrophobicity Test

[0095] The hydrophobicity of the cigarette box lining paper prepared in the above embodiments and comparative examples 1, 2 and 3 was tested. The specific steps are as follows:

[0096] 1. Contact Angle Meter: A high-precision instrument used to measure the contact angle between the inner lining paper of cigarette boxes and the water surface. It can quickly and accurately measure the static contact angle of the inner lining paper of cigarette boxes and record the contact angle change data.

[0097] 2. Experimental steps:

[0098] (1) Prepare the experimental setup: Install a high-precision contact angle measuring instrument, ensure that the instrument is calibrated and functioning properly, and ensure the accuracy and real-time performance of the measurement, which is the foundation of the whole method.

[0099] (2) Place the cigarette paper: Place the cigarette pack liner paper flat on the table, with the bottom layer of the cigarette pack liner paper at the end closest to the table and the top layer at the end furthest from the table. Drop 2μL of water onto the top layer. This step ensures that the cigarette pack liner paper is in complete contact with the water surface.

[0100] (3) Measure the contact angle value: After dripping water onto the inner lining paper of the cigarette box for 10 seconds, immediately measure the contact angle between the inner lining paper of the cigarette box and the water surface using a contact angle measuring instrument.

[0101] (4) The Cobb value (Cobb 60) of the inner lining paper of the cigarette box before and after water absorption was tested according to GB / T 1540-2002. The Cobb value (Cobb 60) was calculated according to the following formula 1:

[0102] C = (m2 - m1) × 100 Formula 1

[0103] Where C is the Cobb value, the unit is (g / m³) 2 m1 is the mass of the inner lining paper of the cigarette box before water absorption, and m2 is the mass of the inner lining paper of the cigarette box after water absorption. The unit is (g).

[0104] The results are shown in Table 1. The contact angles of the cigarette box liner paper in the examples were significantly greater than those in Comparative Examples 1, 2, and 3. Specifically, the contact angle of liner paper #1 was 102°, and its Cobb 60 content was 24 g / m³. 2 The contact angle of the inner lining paper for cigarette boxes of liner paper &1 is 40°, and the Cobb 60 is 69 g / m². 2 The contact angle of the inner lining paper for cigarette boxes of the &2 grade is 83°, and the Cobb 60 grade is 35 g / m². 2 The contact angle of the inner lining paper for cigarette boxes of the &3 grade is 76°, and the Cobb 60 grade is 49 g / m². 2 .

[0105] Table 1. Statistics on contact angle and cobbling value of different cigarette pack lining papers

[0106]

[0107] The results show that the core layer treated by the impregnation method in this embodiment has strong hydrophobicity and can achieve effective waterproofing.

[0108] Test Example 2 Barrier Test

[0109] The barrier properties of the cigarette box liner paper prepared in the above embodiments and comparative examples 1, 2 and 3 were tested respectively. The specific steps are as follows:

[0110] The water vapor transmission rate (WVT) of the inner lining paper for cigarette boxes was determined using the ASTM E96-2005 standard.

[0111] ASTM E96-2005 is one of the standards for the gravimetric method of moisture permeability testing. The gravimetric method is an independent method for testing moisture permeability. Its principle is as follows: under specified temperature and relative humidity, a certain water vapor pressure difference is maintained across the sample, and the amount of water vapor permeating through the sample is measured to calculate the relevant moisture permeability parameters. The gravimetric method can be divided into two methods: the weight gain method (where water vapor permeates into the permeation cup) and the weight loss method (where water vapor permeates out of the permeation cup). This test example uses the weight loss method to test the water vapor permeability of the inner lining paper for cigarette boxes.

[0112] (1) The raw data of the barrier properties test of the inner lining paper for cigarette boxes are shown in Table 2.

[0113] Table 2. Statistical analysis of raw data on water vapor transmission rate of different cigarette box lining papers.

[0114]

[0115] (2) Based on the data shown in Table 2, the water vapor transmission rate (WVT) of the inner lining paper for cigarette boxes is further calculated, as shown in Formula 2 below:

[0116]

[0117] Where G is the weight change of the permeation cup, in grams (g); T is the measurement time, in days (d); and A is the sealing area of ​​the test cup, in m². 2 ).

[0118] The results are shown in Table 3. Among them, the water vapor transmission rate of lining paper #1 is 1.23m. 2 •d; The water vapor transmission rate of the inner lining paper &1 is 4.98m. 2 •d; The water vapor transmission rate of the inner lining paper &2 is 2.65m. 2 •d; The water vapor transmission rate of the inner lining paper &3 is 4.07m. 2 ·d.

[0119] Table 3. Water vapor transmission rate of different cigarette box lining papers

[0120] Inner lining paper <![CDATA[Water vapor transmission rate WVT (m 2 ·d)]]> #1 1.23 &1 4.98 &2 2.65 &3 4.07

[0121] The results show that the water vapor permeability of the cigarette paper prepared by this invention is significantly lower than that of the comparative example, and it has better barrier properties.

[0122] Test Example 3: Tensile Strength Test

[0123] The tensile strength of the cigarette box liner paper in Examples 1, 2, and 3 was tested separately. Tensile strength refers to the maximum tension that paper or paperboard can withstand, and is expressed as the load at which the paper breaks when measured using a standard specimen with a width of 15 mm. Generally, the tensile strength of paper includes transverse tensile strength and longitudinal tensile strength. The transverse tensile strength (N) and longitudinal tensile strength (N) of each liner paper were measured, recorded, and averaged. The results are shown in Table 4 below:

[0124] Table 4. Statistical analysis of tensile strength test results for different cigarette pack lining papers.

[0125]

[0126] The data above shows that by impregnating the core layer of the inner lining paper with different concentration gradients, the tensile strength of the inner lining paper can be increased, allowing the cigarette box to fold normally.

[0127] Test Example 4: Degradability Test

[0128] The biodegradability of the cigarette box liner paper prepared in the above embodiments and comparative examples 1, 2 and 3 was tested. The specific steps are as follows:

[0129] The degradation rate was determined using a biodegradation experiment after 28 days.

[0130] The statistical results are shown in Table 5. The degradation rate of the cigarette box liner paper in the embodiment after 28 days is significantly greater than that of the cigarette box liner paper in Comparative Examples 1, 2 and 3 after 28 days.

[0131] Among them, the 28-day degradation rate of inner lining paper #1 is 82%, the 28-day degradation rate of inner lining paper &1 is 76%, the 28-day degradation rate of inner lining paper &2 is 85%, and the 28-day degradation rate of inner lining paper &3 is 50%.

[0132] Table 5. Statistics on the 28-day degradation rate of different cigarette pack lining papers.

[0133] Inner lining paper 28-day degradation rate (%) #1 82 &1 76 &2 85 &3 50

[0134] The results show that the degradation rate of the cigarette box liner paper prepared by the present invention can reach 80% or more in 28 days, and it can degrade rapidly in a short time, making it a biodegradable and environmentally friendly base paper material.

[0135] Therefore, it can be concluded that this invention provides an innovative, environmentally friendly, bio-waterproof composite liner paper and its manufacturing method. This cigarette box liner paper is composed of three layers of bio-based paper. The bio-based paper uses materials derived from renewable plant resources, such as cellulose and lignin, and possesses biodegradability and renewability. By combining a paper impregnation process, functional bio-waterproofing agent solutions and fragrance solutions are completely infiltrated into the paper. Compared with traditional coating methods, this effectively solves the problems of weak paper performance and discoloration, while also providing fragrance enhancement. It can replace traditional, non-environmentally friendly, and difficult-to-degrade liner papers with poor waterproof and barrier properties, providing a greener and more sustainable solution for the packaging industry.

[0136] In this specification, references to "one embodiment" or "other specific embodiments" mean that a particular feature, structure, or characteristic described in connection with that embodiment / specific implementation is included in at least one embodiment / specific implementation of the invention. Therefore, the phrase "in one embodiment / specific implementation" appearing in various places in this specification does not necessarily refer to the same embodiment / setting, but rather to a range of possibilities. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments / settings in any suitable manner, as will be apparent to those skilled in the art from this disclosure.

[0137] Similarly, it should be understood that in the above description of exemplary embodiments / specific implementations of the invention, various features of the invention are sometimes combined in a single embodiment / specific implementation or its figures and description, with the aim of simplifying the disclosure and aiding in the understanding of one or more of the various aspects of the invention. However, the method of description in this patent should not be construed as reflecting an intention that the claimed features of the invention are more than those expressly stated in each claim, except where explicitly stated otherwise or in obvious technical contradiction or exclusion. Rather, the inventive aspect reflected in the claims lies in not all the features of a single foregoing disclosed embodiment / specific implementation. Therefore, the claims following the detailed description are expressly incorporated herein by reference, each claim existing independently as a separate embodiment / specific implementation of the invention.

[0138] Furthermore, while some embodiments / specific implementations described herein include, but are not limited to, other features included in other embodiments / specific implementations, combinations of features from different embodiments / specific implementations are intended to be within the scope of this invention and form different embodiments / specific implementations, as will be understood by those skilled in the art. Therefore, any changes or modifications to the above embodiments that fall within the essential spirit of this invention will fall within the scope of the claims of this invention.

Claims

1. A bio-based waterproof composite inner lining paper for cigarette boxes, characterized in that, The waterproof composite inner lining paper has a multi-layer hot-pressed composite structure, including a surface layer, a core layer, and a bottom layer; The surface layer is disposed on the upper part of the core layer and includes bio-based paper and adhesive, wherein the adhesive is coated on the bio-based paper at one end near the core layer; The core layer includes the bio-based paper and the bio-waterproofing agent, wherein the bio-based paper is impregnated with the bio-waterproofing agent at different concentration gradients to make the waterproof composite liner paper degradable; The bottom layer is disposed below the core layer and includes the bio-based paper and the adhesive, wherein the adhesive is coated on one end of the bio-based paper near the core layer.

2. The bio-based waterproof composite liner paper for cigarette boxes according to claim 1, characterized in that, The bio-based paper is a lignin-modified material, which includes lignin fibers and polylactic acid. The lignin fiber includes one or more combinations of cellulose, hemicellulose and lignin; The polylactic acid is polymerized from L-lactic acid or D-lactic acid monomers.

3. The bio-based waterproof composite liner paper for cigarette boxes according to claim 1, characterized in that, The bio-waterproofing agent comprises modified lignin sulfonate, nanocellulose, and plant wax.

4. The bio-based waterproof composite liner paper for cigarette boxes according to claim 3, characterized in that, The biological waterproofing agent, in quantities of 100 parts, comprises: The modified lignin sulfonate was 45-55 parts; The nanofibers are 15-20 parts; 8-10 parts of the plant wax; And 10-15 parts pure water.

5. The bio-based waterproof composite liner paper for cigarette boxes according to claim 4, characterized in that, The bio-based paper is sequentially impregnated with the bio-waterproofing agent at at least three concentration gradients, such that the penetration depth of the bio-waterproofing agent is at least 80% of the diameter of the bio-based paper fibers; The immersion temperature for each concentration gradient of the biological waterproofing agent is 25℃~28℃, and the immersion time for each concentration gradient is 20~30s.

6. The bio-based waterproof composite liner paper for cigarette boxes according to claim 1, characterized in that, The adhesive is a water-based adhesive, and 100 parts of the water-based adhesive comprise: 30-35 parts of vinyl acetate; 12-15 parts of polyvinyl alcohol; 50-55 parts soft water; 8-10 parts of ammonium persulfate; 0.01 to 0.02 parts of defoamer.

7. The bio-based waterproof composite liner paper for cigarette boxes according to claim 6, characterized in that, The coating amount of the water-based adhesive is 2.0–3.0 g / m³. 2 3.0~4.0g / m 2 Or 4.0~5.5g / m 2 .

8. The bio-based waterproof composite liner paper for cigarette boxes according to claim 1, characterized in that, The core layer also includes a fragrance agent. The flavoring agent is selected from one or more combinations of cherry, strawberry, bitter orange, apple powder, pear, mint, kudzu root, clove, sandalwood, rose, lotus leaf, chrysanthemum, jasmine, dried tangerine peel, walnut shell, coffee, tea, agarwood, hawthorn, licorice, cocoa, wood ear fungus, lotus seed, and ginger.

9. A method for preparing a bio-based waterproof composite inner liner paper for cigarette boxes, characterized in that, Includes the following steps: Step A: Place the two layers of bio-based paper in the first and second sizing devices that are symmetrically arranged, so that the paper feeding speed of the bio-based paper is uniform. Apply water-based adhesive to one side of the bio-based paper to obtain the top layer and the bottom layer. Step B: The bio-based paper is first impregnated in bio-waterproofing agents of different concentration gradients, and after the first drying, it is impregnated in fragrance agents of different concentrations and dried a second time to obtain the core layer; Step C: The waterproof composite inner lining paper is obtained by hot-pressing the surface layer, the core layer and the bottom layer together and then drying them for the third time.

10. The method for preparing bio-based waterproof composite liner paper for cigarette boxes according to claim 9, characterized in that, The penetration depth of the bio-waterproofing agent and the fragrance agent is at least 80% of the diameter of the bio-based paper fiber; the impregnation temperature of the bio-waterproofing agent at each concentration gradient is 25℃~28℃, and the impregnation time of the bio-waterproofing agent at each concentration gradient is 20~30s; The hot-pressing composite process involves a pressure of 1.0–1.2 MPa, a temperature of 110–125 °C, a composite time of 10–13 s, and a ring compression strength retention rate of 85.0–87.5%. The conditions for both the first and second drying processes are 80–100°C for 3–8 seconds. The third drying condition is drying at 80-100℃ for 6-15 seconds.

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