Method for modifying degradable nonwoven fabric for filter rod

Abstract

This application discloses a method for modifying filter rods with biodegradable nonwoven fabric, comprising the following steps: S1, preparing a biodegradable polymer solution of a certain concentration containing film-forming substances and amino, hydroxyl, and carboxyl groups for later use; preparing a polysiloxane diluent of a certain concentration for later use; preparing a calcium lactate aqueous solution of a certain concentration for later use; S2, first atomizing the biodegradable polymer solution and uniformly spraying it onto the surface of the polylactic acid nonwoven fabric, then transferring the sprayed polylactic acid nonwoven fabric into the calcium lactate aqueous solution, allowing it to stand, and then removing it; S3, transferring the main material after water bath standing into the polysiloxane diluent, allowing it to stand, and then removing it; S4, placing the main material removed in step S3 into a drying oven for sequential drying and heat treatment to obtain the final product. This application performs surface treatment on the biodegradable nonwoven fabric material, which can improve the tensile strength and hardness of the nonwoven fabric, meeting the process requirements for filter rod production, and simultaneously increasing the active groups on the surface of the biodegradable nonwoven fabric, thereby improving its adsorption capacity.

Description

Technical Field

[0001] This application relates to the field of cigarette technology, and in particular to a method for modifying filter rods with biodegradable nonwoven fabric. Background Technology

[0002] Cigarette smoke contains over 5,000 compounds, of which approximately 2,740 are produced by tobacco combustion. Some components in cigarette smoke, such as benzene, aldehydes, volatile nitrosamines, and benzo[a]pyrene, have been proven to be harmful and potentially carcinogenic. Therefore, cigarette filters, as functional components that can effectively filter out some harmful substances, have received widespread attention and application. Currently, the main types of conventional cigarette filter materials on the international market are paper filters, cellulose acetate filters, and polypropylene fiber filters. Paper filters have low retention efficiency, are prone to softening due to moisture, easily absorb aroma components in the smoke, and can impart a papery smell to the smoke, resulting in a low market application rate. Cellulose acetate filters, on the other hand, are widely used in the tobacco industry due to their advantages such as good flavor absorption, sturdy texture, high tar retention efficiency, and attractive appearance. Polypropylene fiber filters have a significant cost advantage over acetate fiber filters, but their tar retention rate is lower than that of acetate fiber filters at the same pressure drop. Furthermore, they have poor heat resistance and are prone to thermal collapse. Therefore, polypropylene filters are mostly used in low-end cigarette products. Besides the commonly used filters mentioned above, new cigarette filter materials internationally include Philtron Nacroco and starch-based filter materials. However, these have not been widely adopted due to their high cost and altered taste, respectively.

[0003] Research on developing composite filters using special additives based on existing filters is very popular. Numerous studies have shown that different filter additives can reduce cigarette tar by 20%-50%. Therefore, researchers have conducted extensive exploratory work on the impact of filter materials and their additives on reducing tar and harm in cigarettes and improving cigarette aroma. Using nonwoven fabric as the molding material for filter rods is a relatively new filter rod production process. The materials are widely available and can be used to develop various functional new filter rods. However, existing ordinary nonwoven fabrics have low mechanical strength, which cannot meet the process requirements for pressing filter rods; ordinary synthetic fiber nonwoven fabrics have low surface activity, resulting in only average filtration effects on smoke; commonly used PP nonwoven fabrics, PET nonwoven fabrics, and other synthetic fiber nonwoven fabrics are difficult to degrade in the natural environment, easily causing environmental pollution. Therefore, it is necessary to improve the mechanical strength, surface activity, and biodegradability of existing nonwoven fabrics. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a method for modifying biodegradable nonwoven fabric for filter rods. The materials selected are water-based polymer materials and biodegradable nonwoven fabric. The surface treatment of the biodegradable nonwoven fabric material improves the tensile strength and hardness of the nonwoven fabric to meet the process requirements of filter rod production. At the same time, it can increase the active groups on the surface of the biodegradable nonwoven fabric and improve the adsorption capacity.

[0005] The technical solution provided by this invention is as follows:

[0006] A method for modifying filter rods with biodegradable nonwoven fabric includes the following steps:

[0007] S1. Prepare a biodegradable polymer solution of a certain concentration containing film-forming substances and amino, hydroxyl, and carboxyl groups for later use; prepare a polysiloxane diluent of a certain concentration for later use; prepare a calcium lactate aqueous solution of a certain concentration for later use.

[0008] S2. First, atomize the biodegradable polymer solution and spray it evenly onto the surface of the polylactic acid nonwoven fabric. Then, transfer the sprayed polylactic acid nonwoven fabric into a calcium lactate aqueous solution, let it stand for a period of time, and then take it out.

[0009] S3. Transfer the main material after step S2 water bath standing to the polysiloxane diluent, and take it out after standing for a period of time.

[0010] S4. Place the main material taken out in step S3 into a drying oven for drying, and then perform heat treatment to obtain the final product.

[0011] Preferably, the biodegradable polymer solution in step S1 is prepared from chitosan, alginate (preferably sodium alginate), and sodium shellac in a mass ratio of (0.05-3):(0.5-1):1.

[0012] Preferably, the total concentration of the degradable polymer solution in step S1 does not exceed 5%.

[0013] Preferably, the polysiloxane diluent in step S1 is prepared by mixing polysiloxane emulsion and fruit acid in a certain proportion.

[0014] Preferably, in step S1, the concentration of polysiloxane in the polysiloxane diluent is 1-3%, and the concentration of fruit acid is 0.5-2%.

[0015] Preferably, the concentration of the calcium lactate aqueous solution in step S1 is 1-2%.

[0016] Preferably, the settling time in step S2 is 10 to 300 seconds.

[0017] Preferably, the settling time in step S3 is 10 to 600 seconds.

[0018] Preferably, after drying in step S4, the moisture content of the main material is 0.4-0.8%.

[0019] Preferably, the heat treatment process in step S4 specifically involves: holding the dried main material at 120–180°C for 60–300 seconds.

[0020] This application has the following advantages over the prior art:

[0021] (1) The hardness of the filter rod is an important physical indicator. Polylactic acid nonwoven fabric is a biodegradable flexible material. The filter rod made directly from it is biodegradable, but has low strength and large absorption resistance fluctuation. Through the modification method of this application, the stiffness and tensile strength of polylactic acid nonwoven fabric can be improved. Sodium alginate has film-forming properties. Through the gelation of calcium salt, it can adhere to the surface of polylactic acid fiber and increase its hardness. According to the test, the hardness of the modified polylactic acid nonwoven filter rod is more than 30% higher than that of the unmodified filter rod.

[0022] (2) The adsorption performance of the filter rod is an important functional indicator. Chitosan has abundant amino and hydroxyl groups. Among them, the amino groups have good reactivity with hydrogen sulfide and hydrogen cyanide, and the hydroxyl groups have reactivity with aldehydes and phenols. Sodium shellac has abundant carboxyl groups, which can combine with nitrogen compounds and alkaline components in flue gas to reduce the irritation of flue gas. This application can effectively improve the adsorption performance of polylactic acid nonwoven filter rod by introducing these two biodegradable active biopolymers. The adsorption performance of the filter rod was tested according to the national standard method. The tar filtration effect of the modified polylactic acid nonwoven filter rod was more than 40% higher than that of the unmodified filter rod and more than 20% higher than that of the cellulose acetate filter rod. The filtration effect of the modified polylactic acid nonwoven filter rod on hydrogen sulfide was more than 40% higher.

[0023] (3) The main material used in this application is polylactic acid nonwoven fabric. The modified materials introduced are all biomass polymers that can be degraded in nature. Therefore, the nonwoven fabric modified by the preparation method of this application has good biodegradability. This material can be applied to cigarette filter rods, new tobacco filter rods, and also to medical mask cloths, odor-absorbing gauze, etc., and has broad market application prospects. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] This invention provides a method for modifying filter rods with biodegradable nonwoven fabric, comprising the following steps:

[0026] S1. Prepare a biodegradable polymer solution of a certain concentration containing film-forming substances and amino, hydroxyl, and carboxyl groups for later use. The total concentration of the biodegradable polymer solution shall not exceed 5%. The biodegradable polymer solution is prepared from chitosan, alginate (preferably sodium alginate), and sodium shellac in a mass ratio of (0.05–3):(0.5–1):1. Prepare a polysiloxane diluent of a certain concentration (the polysiloxane diluent is mainly used to adjust the hydrophobicity of the material surface) for later use. The polysiloxane diluent is a polysiloxane... A siloxane emulsion and fruit acid are prepared in a certain proportion. The concentration of polysiloxane in the polysiloxane dilution is 1-3%, and the concentration of fruit acid is 0.5-2%. Fruit acid can promote the hydrolysis of polysiloxane and promote hydrophobicity. A calcium lactate aqueous solution of a certain concentration is prepared (the function of the calcium lactate aqueous solution is to fix chitosan, sodium alginate, and sodium shellac in the polymer solution, which will produce a cross-linking reaction with these substances and make them adhere to the non-woven fabric), for later use. The concentration of the calcium lactate aqueous solution is 1-2%.

[0027] S2. First, atomize the biodegradable polymer solution and spray it evenly onto the surface of the polylactic acid nonwoven fabric. Then, transfer the sprayed polylactic acid nonwoven fabric into the calcium lactate aqueous solution and let it stand for 10-300 seconds before taking it out.

[0028] S3. Transfer the main material after step S2 water bath standing to the polysiloxane diluent, stand for 10-600 seconds and then take it out.

[0029] S4. Place the main material taken out in step S3 into a drying oven for drying, and then perform heat treatment to obtain the final product.

[0030] In this embodiment, after drying is completed in step S4, the moisture content of the main material is 0.4-0.8%.

[0031] In this embodiment, the heat treatment process in step S4 is specifically as follows: the dried main material is kept at 120-180°C for 60-300 seconds.

[0032] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for modifying filter rods with biodegradable nonwoven fabric, characterized in that, The following steps are included: S1. Prepare a biodegradable polymer solution of a certain concentration containing film-forming substances and amino, hydroxyl, and carboxyl groups for later use; prepare a polysiloxane diluent of a certain concentration for later use; prepare a calcium lactate aqueous solution of a certain concentration for later use. The biodegradable polymer solution is prepared from chitosan, alginate, and sodium shellac in a mass ratio of (0.05–3):(0.5–1):1, and the total concentration of the biodegradable polymer solution does not exceed 5%. S2. First, atomize the biodegradable polymer solution and spray it evenly onto the surface of the polylactic acid nonwoven fabric. Then, transfer the sprayed polylactic acid nonwoven fabric into a calcium lactate aqueous solution, let it stand for a period of time, and then take it out. S3. Transfer the main material after step S2 water bath standing to the polysiloxane diluent, and take it out after standing for a period of time. S4. Place the main material taken out in step S3 into a drying oven for drying, and then perform heat treatment to obtain the final product.

2. The method for modifying filter rods with biodegradable nonwoven fabric according to claim 1, characterized in that, In step S1, the polysiloxane diluent is prepared by mixing polysiloxane emulsion and fruit acid in a certain proportion.

3. The method for modifying filter rods with biodegradable nonwoven fabric according to claim 2, characterized in that, In step S1, the concentration of polysiloxane in the polysiloxane diluent is 1-3%, and the concentration of fruit acid is 0.5-2%.

4. The method for modifying filter rods with biodegradable nonwoven fabric according to claim 1, characterized in that, The concentration of the calcium lactate aqueous solution in step S1 is 1-2%.

5. The method for modifying filter rods with biodegradable nonwoven fabric according to any one of claims 1-4, characterized in that, The settling time in step S2 is 10 to 300 seconds.

6. The method for modifying filter rods with biodegradable nonwoven fabric according to any one of claims 1-4, characterized in that, The settling time in step S3 is 10 to 600 seconds.

7. The method for modifying filter rods with biodegradable nonwoven fabric according to any one of claims 1-4, characterized in that, After drying is completed in step S4, the moisture content of the main material is 0.4-0.8%.

8. The method for modifying filter rods with biodegradable nonwoven fabric according to any one of claims 1-4, characterized in that, The heat treatment process in step S4 specifically involves: keeping the dried main material at 120–180°C for 60–300 seconds.