Environment-friendly moisture-proof cigarette adhesive and preparation method thereof

Abstract

This invention relates to the field of adhesive technology and discloses an environmentally friendly, moisture-proof cigarette adhesive and its preparation method. Using 5-chlorovaleric acid, 3-dimethylaminopropenal, and other raw materials, a synthesized dialdehyde quaternary ammonium salt organosilicon modifier can undergo an aldol condensation reaction with starch, introducing organosilicon and alkenyl double bonds, and then graft copolymerizing with vinyl acetate and acrylic acid. The dialdehyde quaternary ammonium salt organosilicon modifier crosslinks multiple starch molecules together to form a spatial network structure, hindering the binding of starch hydroxyl groups to water molecules and improving the hydrophobic properties of starch. Quaternary ammonium salts can alter the permeability of bacterial cell membranes, affecting cell transport activity and energy metabolism, thereby leading to cell death. The cigarette adhesive prepared by this invention is based on environmentally friendly starch, possessing both moisture-proof and mildew-proof properties, as well as excellent initial tack and adhesive strength. The preparation method is simple and suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to an environmentally friendly, moisture-proof cigarette adhesive and its preparation method. Background Technology

[0002] Cigarette adhesive is a gel-like substance used in the cigarette manufacturing process. It is mainly used for the joining of cigarette sticks, the attachment of cigarette filters, the packaging of cigarette boxes and cartons, the sealing of cigarette cartons, and the bonding during filter rod production. Therefore, the quality of cigarette adhesive significantly affects the quality level of cigarettes. With the increasing speed of high-speed cigarette rolling machines and the continuous improvement of cigarette quality, higher demands are placed on the initial tack, flowability, film-forming properties, quick-drying properties, stability, and safety of cigarette adhesives. Existing cigarette adhesives are no longer suitable for the needs of the cigarette industry, while imported high-speed cigarette adhesives are too expensive. Furthermore, some existing cigarette adhesives lack sufficient moisture resistance, making cigarettes susceptible to moisture during storage and transportation. Ineffective moisture-resistant adhesives cannot effectively prevent mold growth, thus affecting the quality and taste of cigarettes. Therefore, developing a moisture-proof and mold-resistant environmentally friendly cigarette adhesive has become an urgent problem to be solved.

[0003] Currently, the cigarette adhesives used by domestic cigarette factories mainly include plant-based natural polymer adhesives such as starch-based adhesives. These can be used for cigarettes and packaging, have a wide range of applications, are inexpensive, non-toxic, and odorless. However, starch contains a lot of hydroxyl groups, which easily combine with water through hydrogen bonds, resulting in low initial tack, slow drying speed, poor water resistance, and susceptibility to mold growth, making them unsuitable for continuous industrial production on high-speed cigarette machines. Chemically synthesized adhesives are mainly polyvinyl alcohol and polyvinyl acetate emulsions. These adhesives have good adhesion, but their water resistance is poor, their glass transition temperature is high, and their adhesion to complex printed packaging materials is poor, failing to meet the operational requirements of modern high-speed cigarette machines. Furthermore, the resulting adhesives are expensive and have low safety.

[0004] In her article "Research and Development of Corn Starch Modified High-Speed ​​Cigarette Edge Adhesive," Yang Limin mentions that corn starch is oxidized with sodium hypochlorite and borax, then grafted with PVA, followed by emulsification with an emulsifier, and then monomers and initiators are added. The reaction is then kept at a constant temperature, and finally filtered to obtain the cigarette edge adhesive. However, this method still mainly uses polyvinyl acetate, with starch content accounting for only 5-15%, and is not a true starch cigarette adhesive. In addition, the residual monomer content in the adhesive solution is less than 0.5%, which is far from meeting current hygiene and safety standards. Patent number CN110003817A discloses a starch-type cigarette adhesive and its preparation method, including starch raw materials, water-blocking additives, curing accelerators, palatability additives, and antibacterial activators. The starch is debranched and modified, the amylopectin is pretreated, and then acetylated with acetic anhydride to replace the starch. The preparation process is complex and requires the introduction of natural antibacterial activators to prevent the starch adhesive from becoming moldy, making it unsuitable for industrial production.

[0005] For the reasons mentioned above, this invention first prepares a dual-aldehyde crosslinking agent with both waterproof and antibacterial functions, crosslinks and modifies the hydroxyl groups of starch, and then grafts vinyl acetate, acrylic acid, etc. with starch through initiation polymerization to form a dense crosslinked network structure. It does not contain harmful substances such as formaldehyde and phthalates, and is green and environmentally friendly. Summary of the Invention

[0006] The purpose of this invention is to solve the problems existing in the prior art and to provide an environmentally friendly moisture-proof cigarette adhesive and its preparation method. It not only has excellent moisture-proof and waterproof performance, but also has antibacterial and anti-mildew effects, and does not contain harmful substances such as formaldehyde and phthalates, making it green and environmentally friendly.

[0007] This invention is achieved through the following technical solution:

[0008] A method for preparing an environmentally friendly, moisture-proof cigarette adhesive includes the following steps:

[0009] Step (1): Under a nitrogen atmosphere, add starch and deionized water to the reaction flask, stir well, and then add the following: The dialdehyde quaternary ammonium salt organosilicon modifier was stirred and reacted. After the reaction was completed, the pH was adjusted to neutral, and the emulsion was dehydrated, washed, and dried to obtain cross-linked starch.

[0010] Step (2): Under a nitrogen atmosphere, add deionized water to the reaction flask. When the temperature rises to 40-50℃, add cross-linked starch and stir evenly. Then, raise the temperature to 70-90℃ and add acrylic acid, vinyl acetate, initiator and composite emulsifier. Continue the reaction for 1-2 hours. Cool down to 50-60℃ and add a 20-30% polyvinyl alcohol aqueous solution. Adjust the pH to 5-6 with sodium carbonate aqueous solution. Cool down to below 40℃ and filter to obtain environmentally friendly moisture-proof cigarette adhesive.

[0011] In step (1), the starch can be any one of corn starch, tapioca starch, or potato starch.

[0012] In step (2), the initiator is any one of ammonium persulfate, potassium persulfate, or hydrogen peroxide.

[0013] Furthermore, in step (1), the ratio of starch to dialdehyde quaternary ammonium salt organosilicon modifier is 100g:(5-25)g.

[0014] Furthermore, in step (1), the reaction temperature is 65-80℃ and the reaction time is 2-5h.

[0015] Furthermore, in step (2), the composite emulsifier is a mixture of sodium dodecyl sulfate and octylphenol polyoxyethylene ether in a mass ratio of 1:2.

[0016] Furthermore, in step (2), the ratio of cross-linked starch, acrylic acid, vinyl acetate, initiator, composite emulsifier, and polyvinyl alcohol aqueous solution is 100g:(5-10)g:(8-15)g:(0.3-0.8)g:(2-3.5)g:(12-20)g.

[0017] Furthermore, the preparation method of the dialdehyde quaternary ammonium salt organosilicon modifier in step (1) includes the following steps:

[0018] Step S1: Under a nitrogen atmosphere, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 5-chlorovalerate, and dichloromethane were added to a reaction flask. After stirring until homogeneous, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 1-hydroxybenzotriazole, and triethylamine were added. The reaction was carried out at 20-35°C for 12-24 h. The mixture was extracted with deionized water and ethyl acetate, the organic phase was concentrated, and purified by column chromatography to obtain the dichloro long-chain organosilicon intermediate.

[0019] Step S2: Under a nitrogen atmosphere, add dichloro long-chain organosilicon intermediate and N,N-dimethylformamide to a reaction flask, stir until homogeneous, add 3-dimethylaminopropenal, stir to react, and after the reaction is complete, concentrate under reduced pressure to obtain crude product. Dissolve the crude product in methanol, add chloroform to precipitate, filter, wash with deionized water, and dry to obtain dialdehyde quaternary ammonium salt organosilicon modifier.

[0020] Furthermore, in step S1, the ratio of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 5-chlorovalerate, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 1-hydroxybenzotriazole, and triethylamine is 1 mol:(2.05-2.2) mol:(2.5-3.5) mol:(2.8-4.2) mol:(4-6) mol.

[0021] Furthermore, in step S2, the ratio of dichloro long-chain organosilicon intermediate to 3-dimethylaminopropenal is 1 mol: (2.1-2.4) mol.

[0022] Furthermore, in step S2, the reaction temperature is 85-100℃ and the reaction time is 16-32h.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] This invention uses 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 5-chlorovalerate, and 3-dimethylaminopropenal as raw materials to synthesize a dialdehyde quaternary ammonium salt organosilicon modifier. Starch is treated to reduce residual hydroxyl groups and introduce organosilicon and alkenyl double bonds, facilitating graft copolymerization with vinyl acetate and acrylic acid. Polyvinyl alcohol aqueous solution is used as a binder to obtain the dialdehyde quaternary ammonium salt organosilicon modifier.

[0025] The dialdehyde quaternary ammonium salt organosilicon modifier contains dialdehyde groups, which can undergo aldol condensation with the hydroxyl groups in starch, causing multiple starch molecules to crosslink together to form a spatial network structure. At the same time, the alkenyl groups in its structure can initiate polymerization with vinyl acetate and acrylic acid, which is equivalent to bridging and forming chemical bonds in the spatial network structure of crosslinked starch, thus improving the density of the crosslinked structure. The introduction of hydrophobic long-chain alkyl groups can effectively increase the surface tension between starch and water molecules, hindering the binding of starch hydroxyl groups with water molecules and improving the hydrophobic properties of starch. In addition, organosilicon molecules have low surface energy, and the hydrophobic groups such as methyl or other alkyl groups in its molecules are neatly arranged on the outside. When water vapor or raindrops in the air come into contact with the surface of organosilicon materials, the hydrophobicity of the material surface can prevent external moisture from penetrating into the material, thus exhibiting good moisture-proof performance.

[0026] The quaternary ammonium salt in the dialdehyde quaternary ammonium salt organosilicon modifier can reduce surface tension, adsorb onto the bacterial surface, and insert into the lipid layer of the bacterial cell membrane through its hydrophobic groups, altering the permeability of the bacterial cell membrane. This causes small molecule metabolites to leak out of the cell, affecting cell transport activity and energy metabolism, thus leading to cell death. Simultaneously, after the dialdehyde quaternary ammonium salt organosilicon modifier undergoes aldol condensation with starch, the antibacterial quaternary ammonium salt groups are tightly embedded in the cigarette adhesive structure, providing durable antifungal and antibacterial properties. The cigarette adhesive prepared by this invention is based on environmentally friendly starch, possessing both moisture-proof and antifungal properties, as well as excellent initial tack and adhesive strength. The preparation method is simple and suitable for industrial production. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Unless otherwise stated, all raw materials and reagents used in this application are commercially available products or can be prepared by known methods.

[0029] The composite emulsifier is a mixture of sodium dodecyl sulfate and octylphenol polyoxyethylene ether in a mass ratio of 1:2.

[0030] 1,3-Bis(3-aminopropyl)-1,1,3,3-Tetramethyldisiloxane, CAS No. 2469-55-8.

[0031] 5-Chlorovalerate, CAS number 1119-46-6.

[0032] 1-Ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI), CAS No. 25952-53-8.

[0033] 1-Hydroxybenzotriazole (HOBt), CAS number 2592-95-2.

[0034] 3-Dimethylaminopropenal, CAS number 927-63-9.

[0035] Example 1

[0036] (1) Under a nitrogen atmosphere, 25 mmol of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 54 mmol of 5-chlorovalerate, and 200 mL of dichloromethane were added to a reaction flask. After stirring until homogeneous, 75 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 90 mmol of 1-hydroxybenzotriazole, and 125 mmol of triethylamine were added. The reaction was carried out at 25 °C for 16 h. The mixture was extracted with deionized water and ethyl acetate, the organic phase was concentrated, and purified by column chromatography (silica gel, 2-5% methanol in dichloromethane solution) to obtain the dichloro long-chain organosilicon intermediate. The preparation reaction formula is as follows:

[0037]

[0038] (2) Under a nitrogen atmosphere, 18 mmol of a dichloro-based long-chain organosilicon intermediate and 300 mL of N,N-dimethylformamide were added to a reaction flask. After stirring until homogeneous, 40.5 mmol of 3-dimethylaminopropenal was added. The mixture was reacted at 90 °C for 24 h, and the crude product was obtained by concentration under reduced pressure. The crude product was dissolved in methanol, chloroform was added to precipitate the product, filtered, washed with deionized water, and dried to obtain the dialdehyde quaternary ammonium salt organosilicon modifier. The preparation reaction formula is as follows:

[0039]

[0040] (3) Under a nitrogen atmosphere, add 100g of corn starch and 2500mL of deionized water to the reaction flask, stir evenly, add 5g of dialdehyde quaternary ammonium salt organosilicon modifier, react at 70℃ for 3h, adjust the pH to neutral, and dehydrate, wash and dry the emulsion to obtain cross-linked starch.

[0041] (4) Under a nitrogen atmosphere, deionized water was added to the reaction flask. When the temperature reached 45°C, 100g of cross-linked starch was added and stirred evenly. The temperature was then raised to 80°C, and 8g of acrylic acid, 12g of vinyl acetate, 0.5g of ammonium persulfate and 2.5g of composite emulsifier were added. The reaction was continued for 2 hours. The temperature was then lowered to 55°C, and 15g of 25% polyvinyl alcohol aqueous solution was added. The pH was adjusted to 5 with sodium carbonate aqueous solution. The temperature was then lowered to below 40°C, and the material was filtered out to obtain environmentally friendly moisture-proof cigarette adhesive.

[0042] Example 2

[0043] (1) Under a nitrogen atmosphere, 120 mmol of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 246 mmol of 5-chlorovalerate and 600 mL of dichloromethane were added to a reaction flask. After stirring evenly, 300 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 336 mmol of 1-hydroxybenzotriazole and 480 mmol of triethylamine were added. The reaction was carried out at 35 °C for 12 h. The mixture was extracted with deionized water and ethyl acetate, the organic phase was concentrated, and purified by column chromatography (silica gel, 2-5% methanol in dichloromethane solution) to obtain the dichloro long-chain organosilicon intermediate.

[0044] (2) Under a nitrogen atmosphere, 105 mmol of dichloro long-chain organosilicon intermediate and 1260 mL of N,N-dimethylformamide were added to a reaction flask. After stirring evenly, 220.5 mmol of 3-dimethylaminopropenal was added. The reaction was carried out at 100 °C for 16 h. The crude product was obtained by concentration under reduced pressure. The crude product was dissolved in methanol, chloroform was added to precipitate, filtered, washed with deionized water, and dried to obtain the dialdehyde quaternary ammonium salt organosilicon modifier.

[0045] (3) Under a nitrogen atmosphere, add 100g of cassava starch and 2500mL of deionized water to the reaction flask, stir evenly, add 10g of dialdehyde quaternary ammonium salt organosilicon modifier, react at 80℃ for 2h, adjust the pH to neutral, and dehydrate, wash and dry the emulsion to obtain cross-linked starch.

[0046] (4) Under a nitrogen atmosphere, deionized water was added to the reaction flask. When the temperature reached 50°C, 100g of cross-linked starch was added and stirred evenly. The temperature was then raised to 90°C, and 5g of acrylic acid, 8g of vinyl acetate, 0.3g of potassium persulfate and 2g of composite emulsifier were added. The reaction was continued for 1 hour. The temperature was then lowered to 60°C, and 12g of 30% polyvinyl alcohol aqueous solution was added. The pH was adjusted to 6 with sodium carbonate aqueous solution. The temperature was then lowered to below 40°C, and the material was filtered out to obtain environmentally friendly moisture-proof cigarette adhesive.

[0047] Example 3

[0048] (1) Under a nitrogen atmosphere, 50 mmol of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 110 mmol of 5-chlorovalerate and 500 mL of dichloromethane were added to a reaction flask. After stirring evenly, 175 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 210 mmol of 1-hydroxybenzotriazole and 300 mmol of triethylamine were added. The reaction was carried out at 20 °C for 24 h. The mixture was extracted with deionized water and ethyl acetate, the organic phase was concentrated, and purified by column chromatography (silica gel, 2-5% methanol in dichloromethane solution) to obtain the dichloro long-chain organosilicon intermediate.

[0049] (2) Under a nitrogen atmosphere, 40 mmol of dichloro long-chain organosilicon intermediate and 800 mL of N,N-dimethylformamide were added to a reaction flask. After stirring evenly, 96 mmol of 3-dimethylaminopropenal was added. The reaction was carried out at 85 °C for 32 h. The crude product was concentrated under reduced pressure. The crude product was dissolved in methanol, chloroform was added to precipitate, filtered, washed with deionized water, and dried to obtain the dialdehyde quaternary ammonium salt organosilicon modifier.

[0050] (3) Under a nitrogen atmosphere, add 100g of potato starch and 2500mL of deionized water to the reaction flask, stir evenly, add 15g of dialdehyde quaternary ammonium salt organosilicon modifier, react at 65℃ for 5h, adjust the pH to neutral, and dehydrate, wash and dry the emulsion to obtain cross-linked starch.

[0051] (4) Under a nitrogen atmosphere, deionized water was added to the reaction flask. When the temperature reached 40°C, 100g of cross-linked starch was added and stirred evenly. The temperature was then raised to 70°C, and 10g of acrylic acid, 15g of vinyl acetate, 0.8g of hydrogen peroxide and 3.5g of composite emulsifier were added. The reaction was continued for 1 hour. The temperature was then lowered to 50°C, and 20g of 20% polyvinyl alcohol aqueous solution was added. The pH was adjusted to 5 with sodium carbonate aqueous solution. The temperature was then lowered to below 40°C, and the material was filtered out to obtain environmentally friendly moisture-proof cigarette adhesive.

[0052] Example 4

[0053] (1) Under a nitrogen atmosphere, 75 mmol of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 158 mmol of 5-chlorovalerate and 600 mL of dichloromethane were added to a reaction flask. After stirring evenly, 210 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 240 mmol of 1-hydroxybenzotriazole and 270 mmol of triethylamine were added. The reaction was carried out at 30 °C for 15 h. The mixture was extracted with deionized water and ethyl acetate, the organic phase was concentrated, and purified by column chromatography (silica gel, 2-5% methanol in dichloromethane solution) to obtain the dichloro long-chain organosilicon intermediate.

[0054] (2) Under a nitrogen atmosphere, 65 mmol of dichloro long-chain organosilicon intermediate and 920 mL of N,N-dimethylformamide were added to a reaction flask. After stirring evenly, 145.6 mmol of 3-dimethylaminopropenal was added. The reaction was carried out at 95 °C for 28 h. The crude product was concentrated under reduced pressure. The crude product was dissolved in methanol, chloroform was added to precipitate, filtered, washed with deionized water, and dried to obtain the dialdehyde quaternary ammonium salt organosilicon modifier.

[0055] (3) Under a nitrogen atmosphere, add 100g of corn starch and 2500mL of deionized water to the reaction flask, stir evenly, add 20g of dialdehyde quaternary ammonium salt organosilicon modifier, react at 70℃ for 4h, adjust the pH to neutral, and dehydrate, wash and dry the emulsion to obtain cross-linked starch.

[0056] (4) Under a nitrogen atmosphere, deionized water was added to the reaction flask. When the temperature reached 45°C, 100g of cross-linked starch was added and stirred evenly. The temperature was then raised to 85°C, and 9g of acrylic acid, 13g of vinyl acetate, 0.6g of ammonium persulfate and 3g of composite emulsifier were added. The reaction was continued for 2 hours. The temperature was then lowered to 60°C, and 16g of 25% polyvinyl alcohol aqueous solution was added. The pH was adjusted to 6 with sodium carbonate aqueous solution. The temperature was then lowered to below 40°C, and the material was filtered out to obtain environmentally friendly moisture-proof cigarette adhesive.

[0057] Example 5

[0058] (1) Under a nitrogen atmosphere, 35 mmol of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 76.5 mmol of 5-chlorovaleric acid and 285 mL of dichloromethane were added to a reaction flask. After stirring evenly, 112 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 133 mmol of 1-hydroxybenzotriazole and 170 mmol of triethylamine were added. The reaction was carried out at 35 °C for 24 h. The mixture was extracted with deionized water and ethyl acetate, the organic phase was concentrated, and purified by column chromatography (silica gel, 2-5% methanol in dichloromethane solution) to obtain the dichloro long-chain organosilicon intermediate.

[0059] (2) Under a nitrogen atmosphere, 30 mmol of dichloro long-chain organosilicon intermediate and 480 mL of N,N-dimethylformamide were added to a reaction flask. After stirring evenly, 70 mmol of 3-dimethylaminopropenal was added. The reaction was carried out at 95 °C for 28 h. The crude product was concentrated under reduced pressure. The crude product was dissolved in methanol, chloroform was added to precipitate, filtered, washed with deionized water, and dried to obtain the dialdehyde quaternary ammonium salt organosilicon modifier.

[0060] (3) Under a nitrogen atmosphere, add 100g of cassava starch and 2500mL of deionized water to the reaction flask, stir evenly, add 25g of dialdehyde quaternary ammonium salt organosilicon modifier, react at 80℃ for 5h, adjust the pH to neutral, and dehydrate, wash and dry the emulsion to obtain cross-linked starch.

[0061] (4) Under a nitrogen atmosphere, deionized water was added to the reaction flask. When the temperature reached 50°C, 100g of cross-linked starch was added and stirred evenly. The temperature was then raised to 85°C, and 8g of acrylic acid, 12g of vinyl acetate, 0.7g of potassium persulfate and 3.5g of composite emulsifier were added. The reaction was continued for 1 hour. The temperature was then lowered to 60°C, and 18g of 22% polyvinyl alcohol aqueous solution was added. The pH was adjusted to 6 with sodium carbonate aqueous solution. The temperature was then lowered to below 40°C, and the material was filtered out to obtain environmentally friendly moisture-proof cigarette adhesive.

[0062] Comparative Example 1

[0063] (1) Under a nitrogen atmosphere, add 100g of corn starch and 2500mL of deionized water to a reaction flask, stir well, and then add 5g of 4,4'-(ethylene-1,2-diyl)dibenzaldehyde (CAS No. 4720-99-4, structural formula: The mixture was reacted at 70℃ for 3 hours, the pH was adjusted to neutral, and the emulsion was dehydrated, washed, and dried to obtain cross-linked starch.

[0064] (2) Under a nitrogen atmosphere, deionized water was added to the reaction flask. When the temperature reached 45°C, 100g of cross-linked starch was added and stirred evenly. The temperature was then raised to 80°C, and 8g of acrylic acid, 12g of vinyl acetate, 0.5g of ammonium persulfate and 2.5g of composite emulsifier were added. The reaction was continued for 2 hours. The temperature was then lowered to 55°C, and 15g of 25% polyvinyl alcohol aqueous solution was added. The pH was adjusted to 5 with sodium carbonate aqueous solution. The temperature was then lowered to below 40°C, and the material was filtered out to obtain cigarette adhesive.

[0065] Comparative Example 2

[0066] (1) Under a nitrogen atmosphere, add 100g of corn starch and 2500mL of deionized water to a reaction flask, stir well, and then add 5g of glyoxal (CAS No. 107-22-2, structural formula: The mixture was reacted at 70℃ for 3 hours, the pH was adjusted to neutral, and the emulsion was dehydrated, washed, and dried to obtain cross-linked starch.

[0067] (2) Under a nitrogen atmosphere, deionized water was added to the reaction flask. When the temperature reached 45°C, 100g of cross-linked starch was added and stirred evenly. The temperature was then raised to 80°C, and 8g of acrylic acid, 12g of vinyl acetate, 0.5g of ammonium persulfate and 2.5g of composite emulsifier were added. The reaction was continued for 2 hours. The temperature was then lowered to 55°C, and 15g of 25% polyvinyl alcohol aqueous solution was added. The pH was adjusted to 5 with sodium carbonate aqueous solution. The temperature was then lowered to below 40°C, and the material was filtered out to obtain cigarette adhesive.

[0068] Hydrophobicity test: Accurately weigh a cigarette adhesive sample with mass W0, immerse it in a beaker filled with deionized water, sonicate it at 50℃ for 30 min, let it stand for 3 days and 7 days respectively, dry the insoluble matter to constant weight, and weigh it as W1. Mass loss rate = (W0-W1) / W0×100%.

[0069] Table 1 Hydrophobicity Test

[0070]

[0071]

[0072] As shown in the test results above, the hydrophobic properties of cigarette crosslinking gradually increase with the increase of the content of dialdehyde quaternary ammonium salt organosilicon modifier. In Example 4, the mass loss rate was 2.42% after soaking for 3 days. After soaking for 7 days, the mass loss rate did not change much. This is because, on the one hand, the dialdehyde quaternary ammonium salt organosilicon modifier contains dialdehyde groups, which can undergo aldol condensation reaction with the hydroxyl groups in starch, causing multiple starch molecules to crosslink together to form a spatial network structure. At the same time, the alkenyl groups in its structure can initiate polymerization with vinyl acetate and acrylic acid, which is equivalent to bridging and forming chemical bonds in the spatial network structure of crosslinked starch, thus improving the density of the crosslinked structure. On the other hand, the introduction of hydrophobic long-chain alkyl groups can effectively increase the surface tension between starch and water molecules, hindering the combination of starch hydroxyl groups and water molecules, thus improving the hydrophobic properties of starch. In addition, organosilicon molecules have low surface energy, and the hydrophobic groups such as methyl or other alkyl groups in their molecules are neatly arranged on the outside. When water vapor or raindrops in the air come into contact with the surface of organosilicon material, the hydrophobicity of the material surface can prevent external moisture from penetrating into the material, thus exhibiting good hydrophobic properties.

[0073] Comparative Example 1 contains a dialdehyde group, which can undergo aldol condensation with starch, and also contains an alkenyl group, which can be grafted and polymerized with acrylic acid, etc., but does not contain hydrophobic long chains and organosilicon, so its hydrophobic performance is not as good as that of the Example; Comparative Example 2 contains a dialdehyde group, but does not contain an alkenyl group that can be grafted and copolymerized, nor does it contain hydrophobic long chains and organosilicon, so its hydrophobic performance is the worst.

[0074] Anti-mold and antibacterial performance test: The prepared cigarette adhesive was evenly applied to the surface of paper using an sizing metering rod. Then, the sizing surface was pressed tightly against another piece of paper. After drying, the paper samples were cut into 10mm × 10mm pieces and placed in Erlenmeyer flasks. 70mL of PBS and 5mL of bacterial suspension (Escherichia coli and Staphylococcus aureus) were added respectively, so that the concentration of the bacterial suspension in PBS was 1 × 10⁻⁶. 4 -5×10 4 CFU / mL, fix the Erlenmeyer flask on a shaking table, shake at 300 r / min for 2 min at 25℃, take 1 mL of sample solution and dilute it 100 times with PBS as the sample solution before shaking in the experimental group. Continue shaking for 1 h and take 1 mL of sample solution as the sample solution after shaking in the experimental group. Take 1 mL of sample solution before shaking and 1 mL of sample solution after shaking and inoculate it into Petri dishes by agar pouring method. Inoculate 2 Petri dishes for each sample solution. Invert the Petri dishes so that the bottom is facing up and place them in an incubator at 37℃ for 48 h. Perform viable culture and counting according to the prescribed method. The inhibition rate = (average number of colonies before shaking - average number of colonies after shaking) / average number of colonies before shaking × 100%.

[0075] Table 2 Anti-mold and antibacterial performance test

[0076]

[0077] The test results in the table above show that the antifungal and antibacterial properties of cigarette adhesive gradually increase with the increase of the content of dialdehyde quaternary ammonium salt organosilicon modifier. This is because the quaternary ammonium salt in the dialdehyde quaternary ammonium salt organosilicon modifier can reduce surface tension, adsorb onto the bacterial surface, and insert into the lipid layer of the bacterial cell membrane through its hydrophobic groups, changing the permeability of the bacterial cell membrane, causing small molecule metabolites to leak out of the cell, affecting cell transport activity and energy metabolism, thereby leading to cell death. At the same time, after the dialdehyde quaternary ammonium salt organosilicon modifier undergoes aldol condensation with starch, the quaternary ammonium salt groups with antibacterial properties are tightly embedded in the cigarette adhesive structure, resulting in long-lasting antifungal and antibacterial properties. Comparative Examples 1 and 2 do not contain quaternary ammonium salt antibacterial groups and do not have antibacterial properties.

[0078] Initial tack test: The inclined plane rolling ball method is used. When the steel ball and the test surface of the sample make brief contact with a small pressure, the initial tack is evaluated based on the rolling distance of the steel ball on the test surface. A 2mm thick layer of cigarette adhesive is evenly applied to the paper surface. The steel ball is released to roll on the paper surface. The smaller the rolling distance, the greater the initial tack. The data between 30-200mm of rolling distance of the steel ball are recorded.

[0079] Adhesion strength test: Apply cigarette adhesive with a thickness of 2mm evenly to the surface of the paper, cover it with another piece of paper, and use a smooth roller to roll the adhesive part of the sample at a uniform speed. After curing at room temperature and leaving it for 24 hours, use a universal testing machine to conduct a 90° peel strength test.

[0080] Table 3 Mechanical property tests

[0081] Rolling distance (mm) Bond strength (N) Example 1 102.3 2.01 Example 2 85.4 2.23 Example 3 62.1 2.48 Example 4 41.8 2.65 Example 5 35.6 2.70 Comparative Example 1 133.2 1.82 Comparative Example 2 185.4 1.39

[0082] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing an environmentally friendly, moisture-proof cigarette adhesive, characterized in that, The preparation method includes the following steps: Step (1): Under a nitrogen atmosphere, add starch and deionized water to the reaction flask, stir well, and then add the following: The dialdehyde quaternary ammonium salt organosilicon modifier was stirred and reacted. After the reaction was completed, the pH was adjusted to neutral, and the emulsion was dehydrated, washed, and dried to obtain cross-linked starch. Step (2): Under a nitrogen atmosphere, add deionized water to the reaction flask. When the temperature rises to 40-50℃, add cross-linked starch and stir evenly. Then, raise the temperature to 70-90℃ and add acrylic acid, vinyl acetate, initiator and composite emulsifier. Continue the reaction for 1-2 hours. Cool down to 50-60℃ and add a 20-30% polyvinyl alcohol aqueous solution. Adjust the pH to 5-6 with sodium carbonate aqueous solution. Cool down to below 40℃ and filter to obtain environmentally friendly moisture-proof cigarette adhesive. In step (1), the starch is any one of corn starch, tapioca starch, or potato starch. In step (2), the initiator is any one of ammonium persulfate, potassium persulfate, or hydrogen peroxide; In step (1), the ratio of starch to dialdehyde quaternary ammonium salt organosilicon modifier is 100g:(5-25)g; In step (2), the ratio of cross-linked starch, acrylic acid, vinyl acetate, initiator, composite emulsifier, and polyvinyl alcohol aqueous solution is 100g:(5-10)g:(8-15)g:(0.3-0.8)g:(2-3.5)g:(12-20)g.

2. The method for preparing the environmentally friendly moisture-proof cigarette adhesive according to claim 1, characterized in that, The reaction temperature in step (1) is 65-80℃ and the reaction time is 2-5h.

3. The preparation method of the environmentally friendly moisture-proof cigarette adhesive according to claim 1, characterized in that, In step (2), the composite emulsifier is a mixture of sodium dodecyl sulfate and octylphenol polyoxyethylene ether in a mass ratio of 1:

2.

4. The preparation method of the environmentally friendly moisture-proof cigarette adhesive according to claim 1, characterized in that, The preparation method of the dialdehyde quaternary ammonium salt organosilicon modifier in step (1) includes the following steps: Step S1: Under a nitrogen atmosphere, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 5-chlorovalerate, and dichloromethane were added to a reaction flask. After stirring until homogeneous, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 1-hydroxybenzotriazole, and triethylamine were added. The reaction was carried out at 20-35°C for 12-24 h. The mixture was extracted with deionized water and ethyl acetate, the organic phase was concentrated, and purified by column chromatography to obtain the dichloro long-chain organosilicon intermediate. Step S2: Under a nitrogen atmosphere, add dichloro long-chain organosilicon intermediate and N,N-dimethylformamide to a reaction flask, stir until homogeneous, add 3-dimethylaminopropenal, stir to react, and after the reaction is complete, concentrate under reduced pressure to obtain crude product. Dissolve the crude product in methanol, add chloroform to precipitate, filter, wash with deionized water, and dry to obtain dialdehyde quaternary ammonium salt organosilicon modifier.

5. The preparation method of the environmentally friendly moisture-proof cigarette adhesive according to claim 4, characterized in that, In step S1, the ratio of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 5-chlorovalerate, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 1-hydroxybenzotriazole, and triethylamine is 1 mol:(2.05-2.2) mol:(2.5-3.5) mol:(2.8-4.2) mol:(4-6) mol.

6. The method for preparing the environmentally friendly moisture-proof cigarette adhesive according to claim 4, characterized in that, In step S2, the ratio of dichloro long-chain organosilicon intermediate to 3-dimethylaminopropenal is 1 mol: (2.1-2.4) mol.

7. The preparation method of the environmentally friendly moisture-proof cigarette adhesive according to claim 4, characterized in that, In step S2, the reaction temperature is 85-100℃ and the reaction time is 16-32h.

8. An environmentally friendly, moisture-proof cigarette adhesive, characterized in that, It is obtained by the preparation method according to any one of claims 1-7.

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