Polylactic acid tow adhesive for cigarettes as well as preparation method and application of polylactic acid tow adhesive

Abstract

The invention relates to the field of adhesives, and discloses a polylactic acid tow adhesive for cigarettes as well as a preparation method and application of the polylactic acid tow adhesive. The polylactic acid tow adhesive for the cigarette comprises a solute and a filler, wherein the solute is one or more of extra white hydrogenated rosin, hydrogenated rosin, polyvinyl acetate, ethylene-vinyl acetate copolymer, cellulose acetate and nitrocellulose; the organic solvent is one or more of glycerol triacetate, L-methyl lactate, L-ethyl lactate, L-butyl lactate, propylene glycol diacetate and ethylene glycol diacetate. The polylactic acid tow adhesive for the cigarette is simple to prepare and good in bonding effect, can be cured at normal temperature to improve the hardness of a filter stick, and does not influence the smoking taste of the polylactic acid filter stick.

Description

Technical Field

[0001] This invention relates to the field of adhesives, and more particularly to a polylactic acid tow adhesive for tobacco, its preparation method, and its application. Background Technology

[0002] Polylactic acid (PLA), due to its fully biodegradable nature, has become a key option for green transformation across various industries. PLA filter rods can serve as an environmentally friendly alternative to traditional cellulose acetate and polypropylene filter rods. Existing research indicates that PLA tobacco tow has a high adsorption capacity for both polar and non-polar smoke components, and PLA filters possess smoke filtration capabilities comparable to cellulose acetate filters, effectively filtering harmful substances in smoke with superior filtration performance compared to polypropylene filters. However, the current lack of excellent adhesives limits the application of PLA filter rods.

[0003] Currently, the main bonding solutions for polylactic acid (PLA) tows are water-based adhesives, such as water-based polyurethane adhesives (CN101805583A) and acrylic adhesives (CN101693819B). Applying water-based adhesives to PLA tows has the following disadvantages: 1. Insufficient water resistance, resulting in reduced adhesion and hardness in wet conditions; 2. High viscosity and poor wetting properties of the tows, leading to uneven application; 3. Requires oven drying for bonding, but moisture easily seeps into the filter paper, causing wrinkles on the filter surface after drying; 4. Poor storage and process stability; 5. Reduced suction feel of PLA filter rods.

[0004] Therefore, a new type of polylactic acid (PLA) tow adhesive for cigarettes is needed to promote the development of PLA filter rods. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a polylactic acid (PLA) tow adhesive for cigarettes, its preparation method, and its applications. The PLA tow adhesive of this invention is simple to prepare, has good bonding properties, can cure at room temperature to improve the hardness of the filter rod, and does not affect the smoking experience of the PLA filter rod.

[0006] The specific technical solution of the present invention includes: In a first aspect, the present invention provides a polylactic acid tow adhesive for tobacco, which comprises the following raw materials in a total of 100 parts by weight: 10-50 parts of solute and 50-90 parts of organic solvent.

[0007] Wherein: the solute is one or more of the following: extra white hydrogenated rosin, hydrogenated rosin, polyvinyl acetate, ethylene-vinyl acetate copolymer, cellulose acetate and cellulose nitrate; The organic solvent includes one or more of triacetin, methyl L-lactate, ethyl L-lactate, butyl L-lactate, propylene glycol diacetate, and ethylene glycol diacetate.

[0008] First, the solvent of the polylactic acid tow adhesive for tobacco products of the present invention, composed of the above-mentioned raw materials, can slowly evaporate at room temperature. The precipitated solute has the effect of adhering the tow, which can meet the needs of using flavor capsules and improve the hardness of filter rods.

[0009] Secondly, regarding polylactic acid (PLA) filter rods made primarily from PLA tow for cigarette use: On one hand, this invention has discovered that adding an appropriate amount of triacetin to the adhesive can ensure the puffing experience of the PLA filter rod. This is because triacetin can adsorb polar harmful substances in cigarette smoke, thereby improving the filtration effect. For example, its carbonyl group can form hydrogen bonds with the hydroxyl groups of phenol. On the other hand, the solvent used in the adhesive of this invention is an ester substance, which has low toxicity and a high boiling point, resulting in high safety and good processing stability during processing and storage. Furthermore, since PLA is a lipophilic material, the ester substances in the adhesive of this invention are more easily dispersed after being sprayed onto the PLA tow, and the applied adhesive is more evenly distributed on the PLA tow.

[0010] Preferably, the solute is 20-40 parts.

[0011] With a high solute solids content, polylactic acid tow adhesive for tobacco has good bonding effect, but its high viscosity makes it difficult to apply.

[0012] Preferably, the viscosity of the polylactic acid tow adhesive for tobacco is 20-100 mPa·s at 25°C, and more preferably 20-80 mPa·s.

[0013] Generally, the lower the viscosity of the adhesive, the better the atomization effect and the more uniform the spraying. When the adhesive viscosity is high, selectively adding appropriate amounts of one or both of anhydrous ethanol and dearomatic solvent oil, or appropriately increasing the adhesive temperature, can effectively reduce the viscosity.

[0014] Preferably, the total amount of anhydrous ethanol and dearomatic solvent oil in the organic solvent is 2-10 parts.

[0015] Anhydrous ethanol and dearomaticated solvent oil can effectively reduce the viscosity of adhesives. However, if the content of anhydrous ethanol and dearomaticated solvent oil is too low, the effect will be insignificant; conversely, if the content is too high, it will increase production safety hazards.

[0016] Preferably, the organic solvent contains 5-15 parts of triacetin.

[0017] This invention discovers that triacetin, at a content of 5-15%, can effectively improve the puffing experience of polylactic acid (PLA) filter rods without affecting other properties. Specifically, if the content is too low, it cannot effectively improve the smoke filtration effect. Furthermore, this invention also finds that because triacetin dissolves some solute, excessive triacetin can lead to insufficient solute hardening, weakening the filter rod's bonding strength and hardness. When there is too much triacetin, oven treatment is necessary to ensure hardening.

[0018] Preferably, the type of solute is further preferably extra white hydrogenated rosin.

[0019] This invention has found that, under the above-mentioned solute types, the effect of hydrogenated rosin is even better.

[0020] Secondly, the present invention provides a method for preparing polylactic acid tow adhesive for tobacco, which includes the following steps: crushing the solute, mixing it with a solvent, and completely dissolving the solute to obtain the polylactic acid tow adhesive for tobacco.

[0021] Preferably, the solute dissolves at a temperature of 30-60°C.

[0022] Thirdly, the present invention provides the application of the above-mentioned polylactic acid (PLA) tow adhesive for tobacco in the preparation of PLA filter rods for tobacco. Preferably, the application includes: applying the PLA tow adhesive for tobacco to the surface of the opened PLA tow using an adhesive system, then wrapping and slitting it into rods, and curing it to obtain PLA filter rods for tobacco.

[0023] Preferably, the amount of the polylactic acid tow adhesive used in cigarettes is 6-10% of the mass of the polylactic acid tow used in cigarettes.

[0024] Preferably, when the solute / triacetin ratio is ≥3, the curing temperature is room temperature and the curing time is 5-72h; or when the solute / triacetin ratio is <3, the curing temperature is 70-90℃ and the curing time is 1-3h.

[0025] Fourthly, the present invention provides a method for improving the hardness of polylactic acid filter rods for cigarettes and / or improving the smoking experience of filter tips, comprising: applying a polylactic acid tow adhesive for cigarettes to the surface of loosened polylactic acid tow using an adhesive system, followed by wrapping and slitting into rod shapes, and then curing.

[0026] Compared with the prior art, the beneficial effects of the present invention are: (1) The polylactic acid tow adhesive for tobacco products of the present invention does not contain moisture and does not require drying treatment. The solvent can slowly evaporate at room temperature, and the precipitated solute has the effect of adhering the tow, which can meet the needs of the use of popping beads and improve the hardness of the filter rod.

[0027] (2) Regarding polylactic acid filter rods made primarily from polylactic acid filaments for cigarettes: On the one hand, the adhesive of the present invention does not affect the smoking experience of the polylactic acid filter rod; on the other hand, since polylactic acid is an oleophilic material, the esters in the adhesive of the present invention have low viscosity and are easier to disperse after being sprayed onto the polylactic acid filaments, and the applied adhesive is more evenly distributed on the polylactic acid filaments.

[0028] (3) The polylactic acid tow adhesive for tobacco in this invention is an organic volatile adhesive with a high solvent flash point and good safety during storage; the solvent is an ester substance with low toxicity.

[0029] (4) The preparation method of the adhesive of the present invention is simple and applicable to conventional gluing systems. Attached Figure Description

[0030] Figure 1 The curve shows the effect of solids content on the viscosity of polylactic acid tow adhesive for tobacco, with the solute being extra white hydrogenated rosin.

[0031] Figure 2 The curve shows the effect of temperature on the viscosity of polylactic acid tow adhesive for tobacco, with the solute being extra white hydrogenated rosin.

[0032] Figure 3 The cut state of the polylactic acid filter rods of Comparative Example 5 and Example 3.

[0033] Figure 4 Electron micrographs of polylactic acid filter rods from Comparative Example 5 and Example 3. Detailed Implementation

[0034] The present invention will be further described below with reference to embodiments.

[0035] General Implementation Examples In a first aspect, a polylactic acid tow adhesive for tobacco use, comprising, on a total basis of 100 parts by weight, the following raw materials: 10-50 parts solute, 50-90 parts organic solvent. Wherein: The solute is one or more of the following: extra white hydrogenated rosin, hydrogenated rosin, polyvinyl acetate, ethylene-vinyl acetate copolymer, cellulose acetate, and cellulose nitrate.

[0036] The organic solvent is one or more of triacetin, methyl L-lactate, ethyl L-lactate, butyl L-lactate, propylene glycol diacetate, and ethylene glycol diacetate.

[0037] In some preferred embodiments, the viscosity of the polylactic acid tow adhesive for tobacco is 20-80 mPa·s at 25°C, and more preferably 20-80 mPa·s.

[0038] In some preferred embodiments, the solute is 20-40 parts.

[0039] In some preferred embodiments, the organic solvent contains 5-15 parts of triacetin.

[0040] In some preferred embodiments, the organic solvent also includes one or two of anhydrous ethanol and dearomatic solvent oil, with the preferred total amount of anhydrous ethanol and dearomatic solvent oil being 2-10 parts.

[0041] In some preferred embodiments, the solute is further preferably extra-white hydrogenated rosin.

[0042] Secondly, a method for preparing a polylactic acid tow adhesive for tobacco includes the following steps: crushing a solute, mixing it with an organic solvent to completely dissolve the solute, thereby obtaining the polylactic acid tow adhesive for tobacco.

[0043] In some preferred embodiments, the solute is crushed and dissolved in an organic solvent in a sealed container.

[0044] In some preferred embodiments, the dissolution method includes one or more of stirring, oscillation, and ultrasound.

[0045] In some preferred embodiments, the melting temperature is 30-60°C.

[0046] Thirdly, the application of the aforementioned polylactic acid tow adhesive for tobacco in the preparation of polylactic acid filter rods for tobacco.

[0047] In some preferred embodiments, the application includes: applying the polylactic acid (PLA) tow adhesive for tobacco to the surface of the opened PLA tow using an adhesive system, then wrapping and slitting it into rods, and curing it to obtain a PLA filter rod for tobacco.

[0048] In some preferred embodiments, the amount of the polylactic acid tow adhesive applied is 6-10% of the mass of the polylactic acid tow.

[0049] In some preferred embodiments, when the solute / triacetin ratio is ≥3, the curing temperature is room temperature and the curing time is 5-72h; or when the solute / triacetin ratio is <3, the curing temperature is 70-90℃ and the curing time is 1-3h.

[0050] Fourthly, a method for improving the hardness of polylactic acid (PLA) filter rods for cigarettes and / or improving the smoking experience of filter tips includes: applying a PLA tow adhesive to the surface of an opened cigarette tow using an adhesive system, followed by rolling and slitting into rod shapes, and then curing. In some preferred embodiments, the amount of PLA tow adhesive applied accounts for 6-10% of the mass of the PLA tow.

[0051] In some preferred embodiments, when the solute / triacetin ratio is ≥3, the curing temperature is room temperature and the curing time is 5-72h; or when the solute / triacetin ratio is <3, the curing temperature is 70-90℃ and the curing time is 1-3h.

[0052] Specific embodiments and comparative examples It should be noted that the following embodiments are merely examples to clearly illustrate the technical solutions of the present invention, and are not intended to limit the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here, and any obvious variations or modifications derived therefrom are still within the protection scope of this invention.

[0053] Cigarette filter rod samples of each embodiment and comparative example were prepared according to the following preparation method: (1) Preparation of blended solvents: Different organic solvents are added to the container in a certain proportion and stirred to obtain different blended solvents.

[0054] (2) Preparation of adhesive: Different solutes are crushed and added to different blending solvents in a certain proportion. Then, the containers are sealed and stirred at 30°C until the solutes are completely dissolved to obtain the adhesive. To improve the suction feel of polylactic acid filter rods, a certain proportion of triacetin can be added; to reduce the viscosity of the adhesive, a certain proportion of ethanol or dearomatic solvent oil can be added.

[0055] (3) Preparation of polylactic acid filter rods for tobacco: The polylactic acid tow adhesive for tobacco is sprayed onto the opened polylactic acid tow at an application rate of 6-10 wt% through the adhesive application system, and then rolled and cut into polylactic acid filter rods. When the ratio of solute / triacetin is ≥3, it can be placed at room temperature for 5-72 hours until the adhesive is cured; if the ratio is <3, it needs to be placed in an oven at ≥70℃ for 1-5 hours until the adhesive is cured.

[0056] Comparative Example 1 The adhesive for the polylactic acid (PLA) tow used in cigarettes consists of 25 parts of extra-white hydrogenated rosin (Shenzhen Yoshida Chemical Co., Ltd., brand AQ10) and 75 parts of L-ethyl lactate. Its viscosity at 25°C is 30 mPa·s, and it is atomizable. The cigarette tow is made of PLA tow with a total density of 3.89-4.44 ktex. The application rate of the PLA tow adhesive is 9%. After the PLA filter rod is placed at room temperature for 24 hours, the adhesion strength between the PLA tows is weak, the hardness of the filter rod does not increase significantly (75%), and the smoking experience is poor. See Table 1 for details.

[0057] Comparative Example 2 The adhesive for the polylactic acid (PLA) tow used in cigarettes consists of 30 parts of extra-white hydrogenated rosin (Shenzhen Yoshida Chemical Co., Ltd., brand AQ10) and 70 parts of L-ethyl lactate. Its viscosity at 25°C is 53 mPa·s, and it is atomizable. The cigarette tow is made of PLA tow with a total density of 3.89-4.44 ktex. The application rate of the PLA tow adhesive is 9%. After the PLA filter rod is placed at room temperature for 24 hours, the adhesion strength between the PLA tows in the cigarette is high, the hardness of the filter rod increases significantly to 89%, and the smoking experience is poor, as detailed in Table 1.

[0058] Comparative Example 3 The adhesive for the polylactic acid (PLA) tow used in cigarettes consists of 40 parts of extra-white hydrogenated rosin (Shenzhen Yoshida Chemical Co., Ltd., brand AQ10) and 60 parts of L-ethyl lactate. Its viscosity at 25°C is 167 mPa·s, and it is not atomizable. The cigarette tow is made of PLA tow with a total density of 3.89-4.44 ktex. The amount of PLA tow adhesive applied is 9%. After the PLA filter rod is placed at room temperature for 24 hours, the adhesion strength between the PLA tows in the cigarette is high, the hardness of the filter rod increases significantly to 92%, and the smoking experience is poor, as detailed in Table 1.

[0059] Comparative Example 4 The adhesive for the polylactic acid (PLA) tow used in cigarettes consists of 30 parts of extra-white hydrogenated rosin (Shenzhen Yoshida Chemical Co., Ltd., brand AQ10), 65 parts of L-ethyl lactate, and 5 parts of ethanol. Its viscosity at 25°C is 41 mPa·s, and it is atomizable. The cigarette tow is made of PLA tow with a total density of 3.89-4.44 ktex. The amount of PLA tow adhesive applied is 9%. After the PLA filter rod is placed at room temperature for 24 hours, the adhesion strength between the PLA tows is high, the hardness of the filter rod increases significantly to 90%, and the smoking experience is poor, as detailed in Table 1.

[0060] Comparative Example 5 The adhesive for the polylactic acid (PLA) tow used in cigarettes is composed of triacetin, with a viscosity of 9 mPa·s at 25°C, allowing for atomization. The cigarette tow is made of PLA fibers with a total density of 3.89-4.44 ktex. The amount of PLA fiber adhesive applied is 9%. After the PLA filter rod is placed in an 80°C oven for 5 hours, there is no adhesion between the PLA fibers, and the filter rod hardness remains unchanged at 64%, resulting in a good smoking experience. See Table 1 for details.

[0061] Comparative Example 6 The adhesive for the polylactic acid (PLA) tow used in cigarettes is an acrylic water-based adhesive with a solid content of 50%. Its viscosity at 25°C is 200 mPa·s, and it is not atomizable. The cigarette tow is made of PLA tow with a total density of 3.89-4.44 ktex. The amount of PLA tow adhesive applied is 9%. After the PLA filter rod is placed at 55°C for 3 hours, the adhesion strength between the PLA tows in the cigarette is high, the hardness of the filter rod increases significantly to 90%, and the smoking experience is poor, as detailed in Table 1.

[0062] Example 1 The adhesive for the polylactic acid (PLA) tow used in cigarettes consists of 30 parts of extra-white hydrogenated rosin (Shenzhen Yoshida Chemical Co., Ltd., brand AQ10), 65 parts of L-ethyl lactate, and 5 parts of triacetin. Its viscosity at 25°C is 56 mPa·s, and it is atomizable. The cigarette tow is made of PLA tow with a total density of 3.89-4.44 ktex. The amount of PLA tow adhesive applied is 9%. After the PLA filter rod is placed at room temperature for 24 hours, the adhesion strength between the PLA tows is high, the hardness of the filter rod is significantly improved to 87%, and the smoking experience is slightly improved, as shown in Table 1.

[0063] Example 2 The adhesive for the polylactic acid (PLA) tow used in cigarettes consists of 30 parts of extra-white hydrogenated rosin (Shenzhen Yoshida Chemical Co., Ltd., brand AQ10), 50 parts of L-ethyl lactate, and 20 parts of triacetin. Its viscosity at 25°C is 71 mPa·s, and it can be atomized, but the spray volume is reduced. The cigarette tow is made of PLA tow with a total density of 3.89-4.44 ktex. The application rate of the PLA tow adhesive is 9%. After the PLA filter rod is placed at room temperature for 24 hours, the adhesion strength between the PLA tows is weak, the hardness of the filter rod does not increase significantly, and it is 69%. The smoking experience is good, as detailed in Table 1.

[0064] Example 3 The adhesive for the polylactic acid (PLA) tow used in cigarettes consists of 30 parts of extra-white hydrogenated rosin (Shenzhen Yoshida Chemical Co., Ltd., brand AQ10), 55 parts of L-ethyl lactate, 10 parts of triacetin, and 5 parts of ethanol. Its viscosity at 25°C is 52 mPa·s, and it is atomizable. The cigarette tow is made of PLA tow with a total density of 3.89-4.44 ktex. The amount of adhesive applied to the PLA tow is 9%. After the PLA filter rod is placed at room temperature for 24 hours, the adhesion strength between the PLA tows is high, the hardness of the filter rod is significantly improved to 89%, and the smoking experience is good. See Table 1 for details.

[0065] Example 4 The adhesive for the polylactic acid (PLA) tow used in cigarettes consists of 30 parts hydrogenated rosin (Shenzhen Yoshida Chemical Co., Ltd., brand name AJ03), 55 parts L-ethyl lactate, 10 parts triacetin, and 5 parts ethanol. Its viscosity at 25°C is 45 mPa·s, and it is atomizable. The cigarette tow is made of PLA tow with a total density of 3.89-4.44 ktex. The application rate of the PLA tow adhesive is 9%. After the PLA filter rod is placed at room temperature for 24 hours, the adhesion strength between the PLA tows is high, the filter rod hardness is significantly improved to 87%, and the smoking experience is better. See Table 1 for details.

[0066] Example 5 The adhesive for the polylactic acid (PLA) tow used in cigarettes consists of 30 parts polyvinyl acetate (Jiangsu Yinyang Adhesive Materials Co., Ltd., brand 201), 55 parts L-lactic acid ethyl ester, 10 parts triacetin, and 5 parts ethanol. Its viscosity at 25°C is 50 mPa·s, and it is non-atomizable. The cigarette tow is made of PLA tow with a total density of 3.89-4.44 ktex. The application rate of the PLA tow adhesive is 9%. After the PLA filter rod is placed at room temperature for 24 hours, the adhesion strength between the PLA tows is high, the hardness of the filter rod is significantly improved to 86%, and the smoking experience is good. See Table 1 for details.

[0067] Example 6 The adhesive for the polylactic acid (PLA) tow used in cigarettes consists of 30 parts of extra-white hydrogenated rosin (Shenzhen Yoshida Chemical Co., Ltd., brand AQ10), 55 parts of L-methyl lactate, 10 parts of triacetin, and 5 parts of ethanol. Its viscosity at 25°C is 46 mPa·s, and it is atomizable. The cigarette tow is made of PLA tow with a total density of 3.89-4.44 ktex. The amount of PLA tow adhesive applied is 9%. After the PLA filter rod is placed at room temperature for 12 hours, the adhesion strength between the PLA tows in the cigarette is high, the hardness of the filter rod is significantly improved to 88%, and the smoking experience is good. See Table 1 for details.

[0068] Example 7 The adhesive for the polylactic acid (PLA) tow used in cigarettes consists of 30 parts of extra-white hydrogenated rosin (Shenzhen Yoshida Chemical Co., Ltd., brand AQ10), 55 parts of L-butyl lactate, 10 parts of triacetin, and 5 parts of ethanol. Its viscosity at 25°C is 72 mPa·s, and it is atomizable. The cigarette tow is made of PLA tow with a total density of 3.89-4.44 ktex. The application rate of the PLA tow adhesive is 9%. After the PLA filter rod is placed at room temperature for 72 hours, the adhesion strength between the PLA tows in the cigarette is high, the hardness of the filter rod is significantly improved to 89%, and the smoking experience is good. See Table 1 for details.

[0069] Example 8 The adhesive for the polylactic acid (PLA) tow used in cigarettes consists of 30 parts of extra-white hydrogenated rosin (Shenzhen Yoshida Chemical Co., Ltd., brand AQ10), 40 parts of L-ethyl lactate, and 30 parts of triacetin. Its viscosity at 25°C is 93 mPa·s, and it is not atomizable. The cigarette tow is made of PLA tow with a total density of 3.89-4.44 ktex. The application rate of the PLA tow adhesive is 9%. After the PLA filter rod is placed in an oven at 80°C for 2 hours, the adhesion strength between the PLA tows in the cigarette is high, the hardness of the filter rod is significantly improved to 90%, and the smoking experience is good. See Table 1 for details.

[0070] Performance testing Table 1: State of Polylactic Acid Tow Adhesives for Tobacco Products and Their Application in Polylactic Acid Tows for Tobacco Products Sample solute Solid content (%) main solvent TA(%) Ethanol (%) glue state Filter rod status Comparative Example 1 Special white hydrogenated rosin 25 L-ethyl lactate 0 0 Viscosity 30 at 25℃, can be atomized Weak adhesion, 75% hardness, poor suction experience. Comparative Example 2 Special white hydrogenated rosin 30 L-ethyl lactate 0 0 Viscosity 53 at 25℃, can be atomized Strong adhesion, 89% hardness, poor suction experience. Comparative Example 3 Special white hydrogenated rosin 40 L-ethyl lactate 0 0 Viscosity 167 at 25℃, atomization at 50℃ Strong adhesion, 92% hardness, poor suction experience. Comparative Example 4 Special white hydrogenated rosin 30 L-ethyl lactate 0 5 Viscosity 41 at 25℃, can be atomized Strong adhesion, 90% hardness, poor suction experience. Comparative Example 5 / 0 / 100 0 Viscosity 9 at 25℃, can be atomized Weak adhesion, 64% hardness, good suction feel Comparative Example 6 acrylate 50 water 0 0 Viscosity 200 at 25℃, non-atomizing Strong adhesion, 90% hardness, poor suction experience. Example 1 Special white hydrogenated rosin 30 L-ethyl lactate 5 0 Viscosity 56 at 25℃, can be atomized Strong adhesion, 87% hardness, and good suction feel. Example 2 Special white hydrogenated rosin 30 L-ethyl lactate 20 0 Viscosity 71 at 25℃, atomization at 30℃ Weak adhesion, 69% hardness, good suction feel Example 3 Special white hydrogenated rosin 30 L-ethyl lactate 10 5 Viscosity 52 at 25℃, can be atomized Strong adhesion, 89% hardness, and good suction feel. Example 4 Hydrogenated rosin 30 L-ethyl lactate 10 5 Viscosity 45 at 25℃, can be atomized Strong adhesion, 87% hardness, and good suction feel. Example 5 Polyvinyl acetate 30 L-ethyl lactate 10 5 Viscosity 50 at 25℃, can be atomized Strong adhesion, 86% hardness, and good suction feel. Example 6 Special white hydrogenated rosin 30 L-methyl lactate 10 5 Viscosity 46 at 25℃, can be atomized Strong adhesion, 88% hardness, and good suction feel. Example 7 Special white hydrogenated rosin 30 L-butyl lactate 10 5 Viscosity 72 at 25℃, atomization at 30℃ Strong adhesion, 89% hardness, and good suction feel. Example 8 Special white hydrogenated rosin 30 L-ethyl lactate 30 0 Viscosity 93 at 25℃, atomization at 40℃ Strong adhesion, 90% hardness, and good suction feel. Note: TA is the abbreviation for triacetin, and the viscosity unit is mPa•s.

[0071] By comparing and analyzing the data in the table above, we can see that: (1) Analysis of Comparative Examples 1 / 2 / 3 / 5 shows that the higher the solids content of the adhesive, the higher the bonding strength and the harder the filter rod; in Comparative Example 5, because the adhesive has no solute, the filaments cannot bond together, such as Figure 3 As shown, the filter rod is loose after being peeled apart. In Comparative Example 1, the solid content of the adhesive is low, so under the same application amount, the solute content on the surface of the fiber bundle is low, and the fiber bundles cannot be well bonded, resulting in a low filter rod hardness. In Comparative Examples 2 and 3, the solid content of the adhesive is high enough, the bonding strength between the fiber bundles is high, and the filter rod hardness is high.

[0072] (2) Analysis of Comparative Examples 2 / 5 and Examples 1 / 2 shows that the higher the amount of triacetin in the adhesive, the better the puffing experience of the polylactic acid filter rod. The reason is that the solute in the adhesive reduces the puffing experience: after applying the adhesive, the solute adheres to the surface of the polylactic acid filaments, covering the contact between the smoke and the polylactic acid filaments. The polarity of the solute is lower than that of polylactic acid, meaning that the filtration effect on the smoke is poor, thus resulting in a worse puffing experience for the filter rod. However, after adding an appropriate amount of triacetin, because the polarity of triacetin is stronger than that of polylactic acid, its filtration effect on the smoke is better, thus improving the puffing experience. However, the solute can also dissolve in triacetin. When its content is too low, the improvement in smoke filtration is not significant. But when its content is too high, because triacetin has a high boiling point, it is difficult to volatilize at room temperature, resulting in the solute not being able to solidify, and both the bonding strength and the hardness of the filter rod are reduced (Example 2). Furthermore, a comparison between Example 2 and Example 8 shows that adding triacetin increases the viscosity of the system, but the bonding of the filaments can also be achieved by using a drying and curing method.

[0073] (3) Analysis of Comparative Example 6 and Example 3 shows that the adhesive of Example 3 has the same adhesive effect as the acrylic water-based adhesive, but the adhesive of Example 3 has a lower viscosity, can be cured at room temperature, and has a better suction feel.

[0074] Figure 1 The curves show the effect of the solids content of special white hydrogenated rosin on the viscosity of polylactic acid (PLA) tow adhesive for cigarettes. Solids contents of 25%, 30%, and 40% correspond to the PLA tow adhesives for cigarettes in Comparative Examples 1-3, respectively; the formulations with other solids contents use the same raw materials as in Comparative Examples 1-3, differing only in the solute-solvent ratio. Figure 1 It can be seen that, with the same type of raw materials, as the solid content of the adhesive gradually increases, the viscosity of the adhesive also gradually increases.

[0075] Figure 2 The graph shows the effect of temperature on the viscosity of polylactic acid tow adhesive for tobacco products. The solute is extra-white hydrogenated rosin. As shown in the graph, the viscosity of the adhesive gradually decreases with increasing temperature. When the adhesive viscosity is too high and difficult to atomize, its viscosity can be reduced by appropriately increasing the temperature, allowing for smooth atomization and ensuring uniform spraying.

[0076] Figure 3 The cut state of the polylactic acid filter rods in Comparative Example 5 and Example 3. Figure 2 It can be seen that the polylactic acid tow adhesive for Comparative Example 5 is composed of triacetin, and there is no adhesion between the polylactic acid tows. After the filter rod is cut, the tows are loose. However, in Example 3, the adhesive of the present invention is applied, and the polylactic acid tows are firmly bonded. After the filter rod is cut, the tows are in the form of hard columns.

[0077] Figure 4Electron micrographs of polylactic acid filter rods from Comparative Example 5 and Example 3. Figure 4 As can be seen, in Comparative Example 5, when triacetin was applied, electron micrographs showed no signs of adhesion between polylactic acid filaments, while in Example 3, when the adhesive of the present invention was applied, electron micrographs showed obvious signs of adhesion between polylactic acid filaments.

[0078] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A polylactic acid tow adhesive for tobacco use, characterized in that: Based on a total of 100 parts by weight, it includes the following raw materials: 10-50 parts of solute and 50-90 parts of organic solvent; The solute is one or more of the following: extra white hydrogenated rosin, hydrogenated rosin, polyvinyl acetate, ethylene-vinyl acetate copolymer, cellulose acetate, and cellulose nitrate. The organic solvent includes one or more of triacetin, methyl L-lactate, ethyl L-lactate, butyl L-lactate, propylene glycol diacetate, and ethylene glycol diacetate. The viscosity of the polylactic acid tow adhesive for tobacco is 20-100 mPa·s at 25°C.

2. The polylactic acid tow adhesive for tobacco as described in claim 1, characterized in that: The organic solvent also includes one or two of anhydrous ethanol and dearomatic solvent oil.

3. The polylactic acid tow adhesive for tobacco as described in claim 2, characterized in that: The sum of the contents of anhydrous ethanol and dearomatic solvent oil is 2-10 parts.

4. A method for preparing the polylactic acid tow adhesive for tobacco according to any one of claims 1-3, characterized in that... The process includes the following steps: crushing the solute, mixing the solute with a preheated organic solvent under sealed conditions to completely dissolve the solute, thus obtaining polylactic acid tow adhesive for tobacco.

5. The preparation method according to claim 4, characterized in that: The solute dissolves at a temperature of 30-60℃.

6. The use of the polylactic acid tow adhesive for tobacco as described in any one of claims 1-3 or the polylactic acid tow adhesive for tobacco obtained by the preparation method described in claim 4 or 5 in the preparation of polylactic acid filter rods for tobacco.

7. The application according to claim 6, characterized in that: The polylactic acid (PLA) filament adhesive for tobacco is applied to the surface of the opened PLA filaments for tobacco, and then rolled and cut into rods. After curing, PLA filter rods for tobacco are obtained.

8. The application according to claim 7, characterized in that: The amount of the polylactic acid (PLA) tow adhesive used in tobacco products is 6-10% of the mass of the PLA tow.

9. The application according to claim 8, characterized in that: When the solute / triacetin ratio is ≥3, the curing temperature is room temperature and the curing time is 5-72 hours; or When the ratio of solute to triacetin is less than 3, the curing temperature is 70-90℃ and the curing time is 1-3h.

10. A method for improving the hardness of polylactic acid filter rods for cigarettes and / or improving the smoking experience of filter tips, characterized in that... include: The polylactic acid filament adhesive for tobacco as described in any one of claims 1-3 or the polylactic acid filament adhesive for tobacco prepared by the preparation method described in claim 4 or 5 is applied to the surface of the opened polylactic acid filament for tobacco, and then rolled and cut into rods, and cured after the solvent evaporates.

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