Fiber coated with cellulose ester on surface as well as preparation method and application of fiber

Abstract

The invention relates to a fiber with the surface wrapped with cellulose ester and a preparation method and application thereof, and the preparation method of the fiber with the surface wrapped with the cellulose ester comprises the following steps: dipping the fiber in a cellulose ester solution to enable the surface of the fiber to be infiltrated by the cellulose ester solution, and drying to obtain the fiber with the surface wrapped with the cellulose ester. The fiber with the surface wrapped with cellulose ester is used for manufacturing the cigarette filter tip, the quality is good, and the cost is far lower than that of a traditional cellulose acetate fiber filter tip.

Description

Technical Field

[0001] The present invention belongs to the field of fiber preparation, and particularly relates to a fiber with a surface coated with cellulose ester, and a preparation method and application thereof. Background Art

[0002] Cigarette filters are a component of tobacco products, typically used to filter smoke and improve the smoking experience. Currently, the most commonly used filters are made of cellulose acetate and polypropylene fibers.

[0003] Cellulose acetate is a common modified cellulose fiber currently used extensively in cigarette filters and textiles. Cellulose acetate boasts advantages such as being non-toxic, odorless, possessing moderate mechanical strength, easy curing, excellent processability, low draw resistance, excellent filtration performance, and improved flavor, making it an ideal material for cigarette filters. Industrially, cellulose acetate is produced using high-purity pulp as raw material, acetic acid as a solvent, acetic anhydride as an esterifying agent, and sulfuric acid as a catalyst. Cellulose acetate is then esterified to form diacetate cellulose, which is then dissolved and spun. Although cellulose acetate is made from natural cellulose, its high degree of acetylation makes it difficult to biodegrade. Furthermore, cellulose acetate production is very expensive due to its stringent raw material requirements, complex production processes, and high investment costs, resulting in a market price of around 30,000 yuan per ton. Polypropylene fibers are characterized by high strength, low melting point, light specific gravity, high elongation, hard feel, low moisture regain, and stable chemical properties. Polypropylene tow filters effectively filter free radicals in smoke and are relatively affordable. Its main drawbacks are low rod yields and filter tip attachment rates, difficulty in recycling waste tobacco, low air resistance, low hardness, and relatively low tar retention efficiency. The tobacco industry primarily uses it for mid- and low-end cigarettes. Furthermore, polypropylene fiber is a synthetic, fossil-based polymer fiber and is non-degradable.

[0004] Therefore, it is of great significance to provide a fiber material that can replace cellulose acetate fiber and has low price and good quality. Summary of the Invention

[0005] The main purpose of the present invention is to provide a fiber with a surface coated with cellulose ester, a preparation method and application thereof, and the technical problem to be solved is how to provide a fiber material that can replace cellulose acetate fiber and is inexpensive, so as to be more suitable for practical use.

[0006] The purpose of the present invention and the technical problem solved are achieved by adopting the following technical solutions. According to the present invention, a method for preparing a fiber with a surface coated with cellulose ester comprises the following steps:

[0007] The fiber is immersed in a cellulose ester solution so that the surface of the fiber is soaked with the cellulose ester solution, and then dried to obtain a fiber with the surface coated with cellulose ester.

[0008] In some embodiments, according to the aforementioned preparation method, the aforementioned fiber is at least one of cellulose fiber and surface acetylated cellulose fiber.

[0009] In some embodiments, according to the aforementioned preparation method, the acetyl content of the aforementioned surface acetylated cellulose fiber is 0.05% to 1.0%.

[0010] In some embodiments, according to the aforementioned preparation method, the aforementioned cellulose ester includes at least one of cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate.

[0011] In some embodiments, according to the aforementioned preparation method, the linear density of the aforementioned fiber monofilament is 1.0 to 6.0 dtex.

[0012] In some embodiments, according to the aforementioned preparation method, the degree of substitution of the aforementioned cellulose ester is in the range of 1.5 to 3.0.

[0013] In some embodiments, according to the aforementioned preparation method, the mass of the aforementioned cellulose ester solution is 100%, and the proportion of cellulose ester is 0.5% to 10%.

[0014] In some embodiments, according to the aforementioned preparation method, in the aforementioned cellulose ester solution, the solvent is at least one of acetone, dichloromethane, chloroform, methyl formate, ethyl formate, methyl acetate, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, 1,3-dioxolane, 2-methoxyethanol, methanol, ethanol, acetic acid, acetonitrile, dimethyl sulfoxide and water.

[0015] The purpose of the present invention and the technical problems solved therein are also achieved by the following technical solutions: A fiber with a surface coated with cellulose ester according to the present invention comprises: a fiber inner core; and a cellulose ester cladding, wherein the cellulose ester cladding is wrapped around the surface of the fiber inner core.

[0016] The purpose of the present invention and the technical problems solved therein are also achieved by adopting the following technical solutions: A filter tip according to the present invention is made by reprocessing the aforementioned fiber coated with cellulose ester.

[0017] The purpose of the present invention and the technical problems solved therein are also achieved by adopting the following technical solutions: The present invention proposes the application of the aforementioned fiber coated with cellulose ester in the fields of filter materials, textiles or medicine.

[0018] Through the above technical solution, the fiber coated with cellulose ester and its preparation method and application of the present invention have at least the following advantages:

[0019] (1) The present invention uses cellulose fiber or surface acetylated cellulose fiber as raw material, which has an abundant source of raw materials, is cheap, and is not subject to import and export restrictions on pulp raw materials for cellulose acetate.

[0020] (2) The present invention adopts the method of surface-coating cellulose ester to prepare the fiber material, which can significantly reduce the amount of expensive cellulose ester while retaining the good adsorption properties of cellulose ester, thus overcoming the high cost defect of traditional cellulose acetate fiber.

[0021] (3) Since polylactic acid is soluble in organic solvents such as acetone, dichloromethane, and chloroform, the thin polylactic acid fibers immersed in cellulose acetate solution will cause problems such as dissolution and breakage of the polylactic acid fibers. The present invention uses cellulose fibers or surface acetylated cellulose fibers as raw materials. Compared with synthetic polymer fibers such as polylactic acid, cellulose fibers are insoluble in common organic solvents. Therefore, they can maintain their mechanical properties in organic solvents, thus overcoming the problem of dissolution and breakage of polylactic acid fibers immersed in cellulose ester solutions.

[0022] (4) The surface of cellulose fiber is hydrophilic, while cellulose ester is hydrophobic. When cellulose ester is directly coated on the surface of cellulose fiber, the two are not tightly bonded. This results in the surface cellulose ester being easily detached during subsequent processing such as curling, thereby affecting its adsorption performance. When surface acetylated cellulose fiber is used as the raw material, the interfacial bonding between cellulose fiber and cellulose ester can be further improved, preventing the cellulose ester from detaching, thereby improving the stability of product quality.

[0023] (5) Compared with surface-esterified cellulose fibers, fibers coated with cellulose ester have a better adsorption effect on harmful substances in flue gas.

[0024] (6) Since cellulose acetate has a low degree of polymerization, the minimum linear density of cellulose acetate fiber is about 2.2 dtex. Reducing the linear density will lead to problems such as flying waste and high breakage rate during the spinning process of cellulose acetate. The mechanical properties of the fiber used in the present invention are better than those of cellulose acetate fiber. Fibers with lower linear density than cellulose acetate fiber can be used, and the fiber specific surface area is higher, which can give the fiber and the filter better adsorption performance, thereby effectively reducing the content of harmful substances in the smoke. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a scanning electron microscope image of cellulose fibers with cellulose acetate coated on the surface in Example 1 of the present invention;

[0026] Figure 2 This is a scanning electron microscope image of the surface acetylated cellulose fiber coated with cellulose acetate in Example 2 of the present invention.

[0027] Figure 3The scanning electron microscope images of the regenerated cellulose fibers used in the examples and comparative examples of the present invention are shown. DETAILED DESCRIPTION

[0028] To further illustrate the technical means and effectiveness of the present invention in achieving its intended objectives, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail a fiber coated with cellulose ester, its preparation method, and its specific embodiments, structures, features, and effectiveness. In the following description, different references to "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0029] The present invention provides these embodiments to make the present invention thorough and complete, and to fully express the scope of the present invention to those skilled in the art. It should be noted that: unless otherwise specifically stated, the relative arrangement of parts and steps, the composition of materials, numerical expressions and numerical values ​​set forth in these embodiments should be interpreted as merely exemplary, and not as limiting.

[0030] The present invention provides a method for preparing a fiber with a surface coated with cellulose ester, comprising the following steps: immersing the fiber in a cellulose ester solution to wet the surface of the fiber with the cellulose ester solution, and drying to obtain the fiber with a surface coated with cellulose ester.

[0031] Specifically, cellulose ester refers to a derivative in which the hydroxyl groups contained in cellulose are partially or completely esterified. Fibers are substances composed of continuous or discontinuous filaments, including animal fibers, plant fibers, chemical fibers, mineral fibers or synthetic fibers. The fibers can be immersed in the cellulose ester solution by soaking or by spraying the cellulose ester solution on the fiber surface. Conventional drying methods can be used for drying, such as normal pressure drying, reduced pressure drying, hot air circulation drying, etc. The specific drying time and temperature can be determined according to actual conditions. During the drying process, the solvent in the cellulose ester solution on the fiber surface partially evaporates, and the cellulose ester remains on the fiber surface, obtaining a fiber with cellulose ester coated on the surface.

[0032] In some embodiments, according to the aforementioned preparation method, the aforementioned fiber is at least one of cellulose fiber and surface acetylated cellulose fiber.

[0033] Specifically, cellulose fiber or surface acetylated cellulose fiber is used as raw material. Compared with synthetic polymer fibers such as polylactic acid, cellulose fiber is insoluble in common organic solvents. Therefore, it can maintain its mechanical properties in organic solvents, overcoming the dissolution and fracture problem of synthetic polymer fibers such as polylactic acid immersed in cellulose ester solution. More preferably, surface acetylated cellulose fiber is used as raw material. This is because the surface of cellulose fiber is hydrophilic and cellulose ester is hydrophobic. When the cellulose fiber surface is directly wrapped with cellulose ester, there is a problem that the two are not tightly bonded, which leads to the surface cellulose ester being easy to fall off during subsequent processing such as curling, thereby affecting its adsorption performance. When surface acetylated cellulose fiber is used as raw material, the interfacial bonding force between cellulose fiber and cellulose ester can be further improved, preventing the cellulose ester from falling off, thereby improving the stability of product quality. In some embodiments, according to the aforementioned preparation method, the acetyl content of the aforementioned surface acetylated cellulose fiber is 0.05% to 1.0%.

[0034] Specifically, when the acetyl content of the surface acetylated cellulose fiber is less than 0.05%, its degree of acetylation is low and its hydrophilicity is strong, and there is a problem of loose bonding between the two when wrapping cellulose ester; when the acetyl content of the surface acetylated cellulose fiber is greater than 1.0%, the fiber preparation cost is high and it is not suitable for industrialization.

[0035] In some embodiments, according to the aforementioned preparation method, the aforementioned cellulose ester includes at least one of cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate.

[0036] Specifically, cellulose acetate is a chemically modified polymer obtained by esterifying the hydroxyl groups in cellulose molecules with acetic acid. Its properties depend on the degree of acetylation. It is light-stable, non-flammable, and soluble in acetone, methyl acetate, and other materials. It exhibits advantages such as toughness, transparency, and good gloss. It also has good melt flowability and is easily molded and processed. Cellulose acetate propionate is prepared by treating cellulose with propionic acid, then esterifying it with a mixture of propionic acid, propionic anhydride, and acetic acid and acetic anhydride in the presence of sulfuric acid. Cellulose acetate propionate is then hydrolyzed, precipitated, washed, and dried to obtain a cellulose acetate propionate with a certain degree of substitution. Typically, the acetyl group content is 7.5% to 9.0% and the propionyl group content is 39% to 47%. It is tough, weather-resistant, easy to process, and dimensionally stable, but it is not chemical-resistant. Cellulose acetate butyrate is prepared by homogeneously esterifying refined cotton linters with acetic butyric anhydride using sulfuric acid as a catalyst and acetic acid and butyric acid as solvents. Cellulose acetate butyrate is then hydrolyzed, neutralized, precipitated, washed, steamed, and dried to obtain the cellulose acetate butyrate. Cellulose acetate butyrate molecules contain butyryl groups in addition to hydroxyl and acetyl groups. Its properties are related to the content of these three groups. An increase in the hydroxyl content improves its solubility in polar solvents. An increase in the butyryl content reduces its density and expands its solubility range.

[0037] In some embodiments, according to the aforementioned preparation method, the linear density of the aforementioned fiber monofilament is 1.0 to 6.0 dtex.

[0038] Specifically, linear density refers to the thickness of a fiber's monofilaments. A higher linear density indicates a thicker fiber. If the linear density of a fiber's monofilaments is less than 1.0 dtex, fiber processing becomes more difficult, and the fibers are more susceptible to quality defects such as end breakage. Furthermore, the draw resistance of the finished cigarette holder increases, and the adsorption effect becomes too strong, affecting the taste of the cigarette. If the linear density of a fiber's monofilaments exceeds 6.0 dtex, the fiber diameter is too large, resulting in a reduced adsorption effect and an inability to effectively reduce the content of harmful substances in cigarette smoke. Therefore, the linear density of the fiber's monofilaments is controlled between 1.0 and 6.0 dtex.

[0039] In some embodiments, the degree of substitution of the cellulose ester ranges from 1.5 to 3.0.

[0040] Specifically, the degree of substitution of cellulose ester refers to how many hydroxyl groups in the cellulose molecule have been converted to ester groups. When the degree of substitution is less than 1.5, the product is less soluble and has a weaker ability to adsorb harmful substances after being filamented. Therefore, the degree of substitution of cellulose ester ranges from 1.5 to 3.0.

[0041] In some embodiments, according to the aforementioned preparation method, the mass of the aforementioned cellulose ester solution is 100%, and the proportion of cellulose ester is 0.5% to 10%.

[0042] Specifically, if the proportion of cellulose ester is less than 0.5%, the surface of the fiber coated with cellulose ester will carry less cellulose ester. If the proportion of cellulose ester is greater than 10%, the cellulose ester will be difficult to dissolve and the solution viscosity will be too high, making its preparation more difficult and costly.

[0043] In some embodiments, according to the aforementioned preparation method, in the aforementioned cellulose ester solution, the solvent is at least one of acetone, dichloromethane, chloroform, methyl formate, ethyl formate, methyl acetate, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, 1,3-dioxolane, 2-methoxyethanol, methanol, ethanol, acetic acid, acetonitrile, dimethyl sulfoxide and water.

[0044] The present invention provides a fiber with a surface coated with cellulose ester, comprising: a fiber inner core; and a cellulose ester cladding, wherein the cellulose ester cladding is coated on the surface of the fiber inner core.

[0045] The present invention provides a filter tip, which is made by reprocessing the aforementioned fiber with the surface coated with cellulose ester.

[0046] Specifically, the preparation method of the filter tip is the same as the technology of preparing cigarette filters using acetate fiber in the prior art.

[0047] The present invention proposes the application of the aforementioned fiber with the surface coated with cellulose ester in the fields of filter materials, textiles or medicine.

[0048] Specifically, cellulose esters have lipophilic properties. In addition to being used for filtering cigarette smoke, filter materials made from fibers coated with cellulose esters can also be used to make air purifier filters and other materials for adsorbing oily substances in other smoke. Cellulose acetate fiber filaments resemble natural silk, with a soft luster, bright color, good drape and hand feel, and mildew and moth-proofing properties. Fibers coated with cellulose esters can give other textile fibers similar luster and printing and dyeing properties to acetate fibers, reduce the moisture regain of the fibers, and improve their mildew and moth-proofing properties. Cellulose esters have very low adsorption effects on drugs, so fibers coated with cellulose esters can be made into filter materials suitable for sterilizing and filtration of aqueous drug solutions, buffer solutions, serum, and culture media.

[0049] The present invention will be further described below with reference to specific embodiments, but this should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above-mentioned contents of the present invention still fall within the scope of protection of the present invention.

[0050] Unless otherwise specified, the materials and reagents mentioned below are commercially available products familiar to those skilled in the art. Unless otherwise specified, the methods described are all well-known methods in the art. Unless otherwise defined, technical or scientific terms used shall have the same meanings as those commonly understood by those skilled in the art.

[0051] Example 1

[0052] (1) impregnating regenerated cellulose fibers having a monofilament linear density of 3.33 dtex with a cellulose acetate acetone solution having a mass fraction of 5% and a degree of substitution of 2.5, so that the surface of the regenerated cellulose fibers is impregnated with the cellulose acetate solution, drying the fibers in a fiber dryer at 80° C. for 60 seconds, and recovering the acetone to obtain fibers having a surface coated with cellulose acetate;

[0053] (2) The fibers coated with cellulose acetate are prepared into a tow, which is then processed by a filter rod forming machine to obtain a filter tip.

[0054] The filtration effect was determined by measuring total particulate matter and tar using a smoking machine with reference to GB / T 19609-2004 conventional analysis of cigarettes. The total particulate matter was 13.89 mg.

[0055] The scanning electron microscope photograph of the regenerated cellulose fiber with cellulose acetate wrapped on the surface after curling is shown in FIG. Figure 1 As shown, part of the surface-coated cellulose acetate fell off during processing.

[0056] Example 2

[0057] (1) Surface-acetylated regenerated cellulose fiber (acetyl content 0.2%) with a single-filament linear density of 3.33 dtex was impregnated with a cellulose acetate acetone solution having a mass fraction of 5% and a degree of substitution of 2.5, so that the surface of the regenerated cellulose fiber was impregnated with the cellulose acetate solution. The fiber was dried in a fiber dryer at 80° C. for 60 seconds, and the acetone was recovered to obtain a fiber with the surface coated with cellulose acetate;

[0058] (2) The fibers coated with cellulose acetate are prepared into a tow, which is then processed by a filter rod forming machine to obtain a filter tip.

[0059] The filtration effect was determined by measuring total particulate matter and tar using a conventional smoking machine according to GB / T 19609-2004 for cigarette analysis. The total particulate matter was 12.67 mg.

[0060] The scanning electron microscope photograph of the surface acetylated regenerated cellulose fiber with cellulose acetate wrapped on the surface after curling is shown in FIG. Figure 2 As shown, it can be seen that when the surface of the surface acetylated regenerated cellulose fiber is wrapped with cellulose acetate, the two are closely combined, and no surface cellulose acetate is found to fall off.

[0061] Example 3

[0062] (1) Surface-acetylated regenerated cellulose fiber (acetyl content 1.0%) with a single-filament linear density of 1.33 dtex was impregnated with a 1% by mass cellulose acetate acetone solution having a degree of substitution of 2.5, so that the surface of the regenerated cellulose fiber was impregnated with the cellulose acetate solution. The fiber was dried in a fiber dryer at 80° C. for 60 seconds, and the acetone was recovered to obtain a fiber with the surface coated with cellulose acetate;

[0063] (2) The fibers coated with cellulose acetate are prepared into a tow, which is then processed by a filter rod forming machine to obtain a filter tip.

[0064] The filtration effect was determined by measuring total particulate matter and tar using a smoking machine according to GB / T 19609-2004 conventional analysis of cigarettes. The total particulate matter was 9.68 mg.

[0065] Example 4

[0066] (1) Surface-acetylated regenerated cellulose fiber (acetyl content 0.05%) with a monofilament linear density of 6.0 dtex was impregnated with a 10% by mass cellulose acetate acetone solution having a degree of substitution of 2.5, so that the surface of the regenerated cellulose fiber was soaked with the cellulose acetate solution. The fiber was dried in a fiber dryer at 80° C. for 60 seconds, and the acetone was recovered to obtain a fiber with the surface coated with cellulose acetate;

[0067] (2) The fibers coated with cellulose acetate are prepared into a tow, which is then processed by a filter rod forming machine to obtain a filter tip.

[0068] The filtration effect was determined by measuring total particulate matter and tar using a conventional smoking machine according to GB / T 19609-2004 for cigarette analysis. The total particulate matter was 16.87 mg.

[0069] Example 5

[0070] (1) Surface acetylated regenerated cellulose fiber (acetyl content 0.2%) with a single yarn density of 3.33 dtex was immersed in a chloroform solution of cellulose acetate with a degree of substitution of 3.0 and a mass fraction of 5%, so that the surface of the regenerated cellulose fiber was soaked with the cellulose acetate solution. The fiber was dried in a fiber dryer at 80°C for 60 seconds, and the chloroform was recovered to obtain a fiber with a surface coated with cellulose acetate.

[0071] (2) The fibers coated with cellulose acetate are prepared into a tow, which is then processed by a filter rod forming machine to obtain a filter tip.

[0072] The filtration effect was determined by measuring total particulate matter and tar using a conventional smoking machine according to GB / T 19609-2004 cigarette analysis. The total particulate matter was 12.64 mg.

[0073] Example 6

[0074] (1) Surface-acetylated regenerated cellulose fiber (acetyl content 0.2%) with a single-filament linear density of 3.33 dtex was impregnated with a 5% by mass cellulose acetate dimethyl sulfoxide solution having a degree of substitution of 1.5, so that the surface of the regenerated cellulose fiber was soaked with the cellulose acetate solution. The fiber was dried in a fiber dryer at 150° C. for 60 seconds, and the dimethyl sulfoxide was recovered to obtain a fiber with the cellulose acetate surface coated thereon.

[0075] (2) The fibers coated with cellulose acetate are prepared into a tow, which is then processed by a filter rod forming machine to obtain a filter tip.

[0076] The filtration effect was determined by measuring total particulate matter and tar using a conventional smoking machine according to GB / T 19609-2004 for cigarette analysis. The total particulate matter was 13.35 mg.

[0077] Example 7

[0078] (1) Surface-acetylated regenerated cellulose fiber (acetyl content 0.2%) with a single-filament linear density of 3.33 dtex was impregnated with a cellulose acetate propionate acetone solution having a mass fraction of 2% and a degree of substitution of 2.5, so that the surface of the regenerated cellulose fiber was impregnated with the cellulose acetate propionate solution. The fiber was dried in a fiber dryer at 80° C. for 60 seconds, and the acetone was recovered to obtain a fiber with the cellulose acetate propionate coated on the surface.

[0079] (2) The fibers coated with cellulose acetate propionate are prepared into a tow, which is then processed by a filter rod forming machine to obtain a filter tip.

[0080] The filtration effect was determined by measuring total particulate matter and tar using a smoking machine according to GB / T 19609-2004 conventional analysis of cigarettes. The total particulate matter was 12.89 mg.

[0081] Example 8

[0082] (1) Surface-acetylated regenerated cellulose fiber (acetyl content 0.2%) with a single-filament linear density of 3.33 dtex was impregnated with a cellulose acetate butyrate acetone solution having a mass fraction of 2% and a degree of substitution of 2.5, so that the surface of the regenerated cellulose fiber was impregnated with the cellulose acetate butyrate solution. The fiber was dried in a fiber dryer at 80° C. for 60 seconds, and the acetone was recovered to obtain a fiber with the cellulose acetate butyrate coated on the surface.

[0083] (2) The fibers coated with cellulose acetate butyrate are prepared into a tow, which is then processed by a filter rod forming machine to obtain a filter tip.

[0084] The filtration effect was determined by measuring total particulate matter and tar using a conventional smoking machine according to GB / T 19609-2004 cigarette analysis. The total particulate matter was 12.44 mg.

[0085] Comparative Example 1

[0086] A cellulose acetate filter with a single-filament linear density of 3.33 dtex and a degree of substitution of 2.5 was prepared into a tow and then processed on a filter rod forming machine to produce the filter. The filtration performance was measured using a conventional smoking machine according to GB / T 19609-2004 for the analysis of total particulate matter and tar, and the total particulate matter content was 12.25 mg.

[0087] Comparative Example 2

[0088] Regenerated cellulose fibers with a single-filament linear density of 3.33 dtex were prepared into tow and then processed into filter rods using a filter rod forming machine. The filter performance was measured using a conventional smoking machine according to GB / T 19609-2004 for the analysis of total particulate matter and tar, and the total particulate matter content was 23.22 mg.

[0089] Scanning electron microscope pictures of regenerated cellulose fibers Figure 3 As shown, it can be clearly observed that the surface of the regenerated cellulose fiber is not very smooth.

[0090] Comparative Example 3

[0091] Polylactic acid fibers with a single-filament linear density of 3.33 dtex were impregnated with a cellulose acetate acetone solution with a mass fraction of 5% and a degree of substitution of 2.5. Due to the swelling and dissolution of the polylactic acid fibers in the acetone, their mechanical properties deteriorated significantly. When the polylactic acid fibers were pulled in the impregnation tank, the polylactic acid fibers broke severely, and it was impossible to continuously prepare polylactic acid fibers with cellulose acetate coated on the surface.

[0092] The technical features in the claims and / or the specification of the present invention may be combined, and the manner of combination is not limited to the combination obtained by reference in the claims. The technical solutions obtained by combining the technical features in the claims and / or the specification are also within the scope of protection of the present invention.

[0093] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiment based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a fiber coated with cellulose ester, characterized in that: The method comprises the following steps: immersing the fiber in a cellulose ester solution to wet the fiber surface with the cellulose ester solution, and drying the fiber to obtain the fiber with the surface coated with cellulose ester.

2. The preparation method according to claim 1, characterized in that The fiber is at least one of cellulose fiber and surface acetylated cellulose fiber.

3. The preparation method according to claim 2, characterized in that The acetyl content of the surface acetylated cellulose fiber is 0.05% to 1.0%.

4. The preparation method according to claim 1, characterized in that The cellulose ester includes at least one of cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate.

5. The preparation method according to claim 1, characterized in that The linear density of the fiber monofilament is 1.0 to 6.0 dtex.

6. The preparation method according to claim 1, characterized in that The degree of substitution of the cellulose ester is in the range of 1.5 to 3.

0.

7. The preparation method according to claim 1, characterized in that Taking the mass of the cellulose ester solution as 100%, the proportion of cellulose ester is 0.5% to 10%.

8. The preparation method according to claim 1, characterized in that In the cellulose ester solution, the solvent is at least one of acetone, dichloromethane, chloroform, methyl formate, ethyl formate, methyl acetate, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, 1,3-dioxolane, 2-methoxyethanol, methanol, ethanol, acetic acid, acetonitrile, dimethyl sulfoxide and water.

9. A fiber coated with cellulose ester, characterized in that: include: Fiber core; as well as, A cellulose ester cladding layer is wrapped around the surface of the fiber inner core.

10. A filter tip, characterized in that: It is obtained by reprocessing the fiber with the surface coated with cellulose ester as claimed in claim 9.

11. Use of the fiber coated with cellulose ester according to claim 9 in the fields of filter materials, textiles or medicine.

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