A preparation method of sandalwood cellulose fiber

Abstract

The present invention belongs to the field of functional fibers, specifically, a method for preparing sandalwood cellulose fiber, the preparation method including the preparation of an amphiphilic cross-linking agent, the preparation of a modified sandalwood essential oil β-cyclodextrin coating, the preparation of a coating emulsion, the preparation of a blended spinning solution, spinning and post-processing. The main components of sandalwood essential oil are α-santalol, β-santalol, santalene, etc., which are sesquiterpenoid compounds and contain a double bond structure; sandalwood essential oil and an amphiphilic cross-linking agent are coated with β-cyclodextrin, and under the conditions of high temperature ultraviolet light irradiation, the active ingredient in the sandalwood essential oil reacts with the unsaturated double bond in the amphiphilic cross-linking agent to generate a cross-linked structure, obtaining a modified sandalwood essential oil β-cyclodextrin coating with a cross-linked structure inside, and a better sustained-release effect. The sandalwood cellulose fiber prepared by the present invention has an active ingredient loss rate of less than 5% after washing fifty times.

Description

Technical Field

[0001] The invention belongs to the field of functional fibers, and particularly relates to a method for preparing sandalwood cellulose fibers. Background Art

[0002] Sandalwood, a traditional Chinese medicine, is the dried heartwood of the Santalum album tree. It promotes qi flow, relieves pain, dispels cold, and regulates qi. Its fragrant aroma soothes the nerves, relieves boredom, soothes the mind and body, promotes inner peace, and combats depression. Regular exposure to it can effectively improve one's health. Its scent repels insects and moths, making it suitable for clothing preservation and other deodorizing and purification purposes. Sandalwood essential oil, extracted from sandalwood, has a wide range of uses, but its main components, such as α-santalol and β-santalol, are volatile, preventing long-term use. Microencapsulation can effectively prevent the evaporation of the essential oil. β-cyclodextrin is a stable, non-toxic crystalline compound, a cyclic oligosaccharide composed of end-to-end linked glucose molecules. It has a unique spatial structure—a hollow cylindrical structure. This gives the inside and outside of the cyclodextrin cavity distinct properties: a hydrophilic exterior and a lipophilic interior, making it a popular wall material for microcapsules.

[0003] Patent CN119425550A discloses that inclusion compound microcrystals are obtained by encapsulating essential oil with β-cyclodextrin, and then the inclusion compound microcrystals are used as an emulsifier to prepare an inclusion compound microcrystal suspension, sandalwood essential oil and resin are added, and then a coagulation reaction is carried out at a certain temperature to prepare a microcapsule suspension. The microcapsules have a high essential oil encapsulation rate and good stability.

[0004] Patent CN107287033A discloses a method for preparing sandalwood essential oil microcapsules. The method involves adding a sandalwood essential oil alcohol solution dropwise to a β-cyclodextrin solution at 54-57°C, stirring, cooling to 3-5°C, and allowing to stand overnight. The solution is then filtered and vacuum-dried to produce the sandalwood essential oil microcapsules. CN103394313A discloses using β-cyclodextrin as a wall material to encapsulate the essential oil. After cooling the capsule solution to room temperature, the solution is then placed at 4-10°C and allowed to stand for 20-40 hours. After vacuum filtration, the solution is freeze-dried at -40-60°C to a constant weight, yielding a white microcapsule product.

[0005] CN107550980A also discloses a method for preparing a lavender oil β-cyclodextrin inclusion compound.

[0006] The above inventions have all successfully achieved the encapsulation of essential oils with β-cyclodextrin, and described the stability and embedding rate after encapsulation, but did not describe the particle size of the encapsulated material, the sustained-release effect, and the stability of the emulsion in subsequent applications.

[0007] Furthermore, post-finishing methods result in weak binding forces between the coating and the fibers, leading to significant loss of sandalwood essential oil after repeated washing, resulting in a decrease in the effectiveness of the sandalwood essential oil. The present invention aims to coat sandalwood essential oil. Through process control, a modified sandalwood essential oil β-cyclodextrin coating emulsion is prepared, achieving a stable system, high coating rate, and controllable coating particle size. This emulsion is then added to a spinning solution to produce sandalwood regenerated cellulose fiber with sustained-release fragrance, meeting consumers' expectations for long-lasting fragrance. At the same time, the fabric retains the excellent properties of regenerated cellulose fiber in terms of softness, gloss, breathability, and skin feel. Summary of the Invention

[0008] In order to solve the problems existing in the prior art, the present invention provides a method for preparing sandalwood cellulose fiber to achieve the following invention objectives:

[0009] 1. The particle size of the modified sandalwood essential oil β-cyclodextrin coating is controllable and stable, and it has good compatibility with the viscose spinning solution and does not delaminate;

[0010] 2. Use β-cyclodextrin to coat sandalwood essential oil to reduce the loss of sandalwood essential oil during cellulose molding and post-processing, and increase the content of sandalwood essential oil in the fiber;

[0011] 3. Enhance the bonding effect between the modified sandalwood essential oil β-cyclodextrin coating and the fiber, and avoid the coating falling off due to washing, which will greatly weaken the fiber functionality;

[0012] 4. Improve the sustained-release effect of sandalwood essential oil, prevent it from being released too quickly during washing, extend the use time, and make the functionality more lasting and stable.

[0013] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0014] A method for preparing sandalwood cellulose fiber, comprising the following steps:

[0015] S1. Preparation of amphiphilic cross-linking agent

[0016] Add long-chain di-isomerized aliphatic diol polyoxyethylene ether and triethylamine to dichloromethane in an ice bath and stir for 30-40 minutes, then add acryloyl chloride dropwise, stir for 3-4 hours after the addition is complete, then heat to 25-30°C and stir to react for 12-14 hours. After the reaction is completed, filter under reduced pressure and rotary evaporate to obtain the product. Dissolve the product with an appropriate amount of ether and continue to filter under reduced pressure and rotary evaporate to obtain an amphiphilic crosslinking agent.

[0017] Preferably, the temperature of the ice bath is 0-5°C.

[0018] Preferably, the molar ratio of the long carbon chain di-isomerized aliphatic diol polyoxyethylene ether, triethylamine and acryloyl chloride is 9-11:12-14:16-20.

[0019] Preferably, the stirring rate is 300-600 r / min.

[0020] Preferably, the dropping rate of the acryloyl chloride is 15-20 ml / min.

[0021] The long-chain di-isomerized aliphatic diol polyoxyethylene ether contains two hydroxyl groups. Under the catalytic action of triethylamine, the hydroxyl groups in the long-chain di-isomerized aliphatic diol polyoxyethylene ether react with acryloyl chloride to form an ester bond, and the molecular chain of the long-chain di-isomerized aliphatic diol polyoxyethylene ether is modified with an acrylate group containing an unsaturated double bond. At the same time, the molecule contains a hydrophobic CH chain segment and a hydrophilic polyoxyethylene chain segment, so it has amphiphilicity; the two modified unsaturated double bonds can serve as active sites and have a cross-linking effect.

[0022] S2. Preparation of modified sandalwood essential oil β-cyclodextrin coating

[0023] S21, adding β-cyclodextrin to deionized water, heating and stirring until completely dissolved, to obtain a β-cyclodextrin solution;

[0024] S22, adding sandalwood essential oil and an amphiphilic cross-linking agent to anhydrous ethanol, stirring and dissolving at room temperature to obtain an ethanol solution of sandalwood essential oil;

[0025] S23, adding the ethanol solution of sandalwood essential oil to the β-cyclodextrin solution to obtain a mixed solution;

[0026] S24, adding the mixed solution to a jacketed homogenizer for homogenization, precipitating at low temperature, filtering, washing with petroleum ether, and drying to obtain a sandalwood essential oil β-cyclodextrin coating;

[0027] S25. Subjecting the sandalwood essential oil β-cyclodextrin coating to ultraviolet irradiation treatment to obtain a modified sandalwood essential oil β-cyclodextrin coating having a cross-linked structure inside.

[0028] Preferably, the temperature of the heating and stirring in S21 is 65-75° C., and the mass concentration of the β-cyclodextrin solution is 8-12%.

[0029] Preferably, the volume ratio of sandalwood essential oil to anhydrous ethanol in S22 is 1:1-10.

[0030] Preferably, the amount of the amphiphilic cross-linking agent added in S22 is 3-5% of the mass of the sandalwood essential oil.

[0031] Preferably, the mass ratio of the sandalwood essential oil in the S23 sandalwood essential oil ethanol solution to the β-cyclodextrin in the β-cyclodextrin solution is 1:5-10.

[0032] Preferably, the homogenization treatment in S24 is carried out for 60 to 90 minutes, at a temperature of 18 to 23° C., and at a rotation speed of 3000 to 4000 r / min. Homogenization can improve the uniformity of the particle size of the coated material.

[0033] Preferably, the temperature of the low-temperature precipitation in S24 is 0-5°C.

[0034] Preferably, the temperature of the ultraviolet light treatment in S25 is 50-60°C, and the light intensity is 20-30 mW / cm 2 , wavelength is 365nm, time is 40 to 50 minutes.

[0035] The main components of sandalwood essential oil are α-santalol, β-santalol, and santalene, which are sesquiterpenoids containing double bonds. Under high-temperature ultraviolet light, the double bonds in the amphiphilic crosslinker are excited to form free radicals, which react with the double bonds in α-santalol, β-santalol, and santalene to form crosslinked structures. This results in a modified sandalwood essential oil-encapsulated β-cyclodextrin with an internal crosslinked structure, resulting in a more sustained-release effect. The amphiphilic crosslinker also contains flexible polyoxyethylene ether segments, resulting in a tough internal crosslinked structure within the microcapsules. This not only provides excellent support but also offers excellent flexibility and durability, making it more resistant to washing and preventing the loss of active ingredients.

[0036] In step S22, no initiator is added to prevent the formation of crosslinks before coating, which could affect the coating efficiency, and to avoid contamination caused by residual initiator. In step S25, a photothermal crosslinking method is used to control the reaction conditions to avoid excessive crosslinking, which could cause the coating to become stiff, or insufficient crosslinking, which could cause rapid release upon washing. The crosslinked modified sandalwood oil-based β-cyclodextrin coating achieved a coating efficiency of 86.1-88.7%.

[0037] S3. Preparation of coating emulsion

[0038] The modified sandalwood essential oil β-cyclodextrin coating is added to deionized water and stirred for 15 to 25 minutes, then a butter acrylic thickener is added and stirred for 5 to 10 minutes, and a sodium hydroxide solution is added and stirred to adjust the pH to 8 to 10 to obtain a coating emulsion with D90 less than 2.0 μm and PDI less than 0.3.

[0039] Preferably, the added amount of the modified sandalwood essential oil β-cyclodextrin coating is 15-20% of the mass of deionized water, and the added amount of the butter acrylic thickener is 2-4% of the mass of deionized water.

[0040] Preferably, the mass fraction of the sodium hydroxide solution is 10-13%.

[0041] S4. Preparation of blended spinning solution

[0042] Cotton pulp, wood pulp, bamboo pulp or a mixture thereof is selected as raw material, and viscose spinning solution is prepared through processes such as impregnation, pressing, crushing, aging, yellowing, dissolving, filtering and degassing; the coating emulsion is added into the viscose spinning solution in proportion before spinning and mixed evenly to prepare a blended spinning solution.

[0043] Preferably, the viscosity of the cellulose spinning solution is 50-70s (falling ball method), the degree of maturity is 12-18mL (15% NH4CL), the methylcellulose content is 6.8-7.2wt%, and the sodium hydroxide content is 4.5-5.2wt%.

[0044] Preferably, the added amount of the coating emulsion is 5 to 8 wt % of the modified sandalwood essential oil β-cyclodextrin coating in the coating emulsion based on the content of the methyl cellulose.

[0045] S5, Spinning

[0046] After the blended spinning solution is ejected from the spinneret, it is formed and drawn in a coagulation bath to obtain a primary fiber bundle. The bundle is further formed in the second bath, enters the third bath for plasticization and drawing, and then enters the post-processing process after being cut.

[0047] Preferably, in the coagulation bath, sulfuric acid is 20-30 g / L, sodium sulfate is 40-60 g / L, zinc sulfate is 0.2-1 g / L, the temperature is 25-30°C, and the draft is -20-0%; the second bath sulfuric acid is 10-20 g / L, sodium sulfate is 20-30 g / L, the temperature is 30-35°C, and the draft is 50-80%; the third bath sulfuric acid is 15-20 g / L, the temperature is 85-95°C, and the draft is 15-20%; the spinning rate is 30-40 m / min.

[0048] It adopts a coagulation bath with low temperature, low concentration composition and low spinning speed, multi-bath molding and multi-stage stretching. The fiber molding and stretching are relatively slow, the internal structure of the fiber is relatively stable and dense, the internal stress is small, the fiber performance index is high, the coating is more stable inside the fiber, and it is resistant to subsequent washing.

[0049] S6. Post-processing

[0050] The cut fiber bundles are washed, desulfurized, bleached, oiled and dried to obtain sandalwood cellulose fibers.

[0051] Due to the adoption of the above technical solution, the technical effects achieved by the present invention are:

[0052] 1. The sandalwood cellulose fiber prepared by the present invention has a dry breaking strength of 2.58 to 2.82 cN / dtex and a wet breaking strength of 1.36 to 1.74 cN / dtex; has good moisture absorption effect, and a moisture regain of 14.3 to 15.1%.

[0053] 2. A butter acrylic thickener with moisturizing effect is added to the coating emulsion, which has a thickening effect under alkaline conditions, improves the stability of the system and the compatibility of the modified sandalwood essential oil β-cyclodextrin coating with the viscose spinning solution, and further improves the moisturizing effect of the fiber.

[0054] 3. The coating emulsion is added to the viscose spinning solution before spinning. The modified sandalwood oil-based β-cyclodextrin coating exhibits excellent compatibility with cellulose macromolecules, dispersing evenly in the viscose spinning solution and distributing uniformly throughout the fibers after forming. Furthermore, the hydroxyl groups on the surface of the modified sandalwood oil-based β-cyclodextrin coating form hydrogen bonds with the hydroxyl groups on the cellulose macromolecules, strengthening the bond.

[0055] 4. The sandalwood cellulose fiber prepared by the present invention cross-links the sandalwood essential oil in the coating, has a good sustained-release effect of the sandalwood essential oil, and its fragrance and antibacterial functions are more lasting. After washing with water fifty times, the loss rate of the effective ingredient of the sandalwood essential oil is less than 5%.

[0056] 5. The sandalwood cellulose fiber prepared by the present invention has a good antibacterial effect. After testing, the antibacterial rates against Staphylococcus aureus and Escherichia coli after washing with water fifty times are both above 90% (determined in accordance with GB / T 20944.3-2008), and the mite repellency rate is greater than 60% (determined in accordance with the repellency method of GB / T 24253-2009 / 9.1). DETAILED DESCRIPTION

[0057] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with preferred embodiments.

[0058] Example 1: A method for preparing sandalwood cellulose fiber, the preparation method comprising the following steps:

[0059] S1. Preparation of amphiphilic cross-linking agent

[0060] Add long-chain di-isomerized aliphatic diol polyoxyethylene ether and triethylamine to dichloromethane in an ice bath and stir for 35 minutes. Then add acryloyl chloride dropwise and stir for 3.5 hours after the addition is complete. Then heat to 28°C and stir to react for 13 hours. After the reaction is completed, filter under reduced pressure and rotary evaporate to obtain the product. Dissolve the product with an appropriate amount of ether and continue to filter under reduced pressure and rotary evaporate to obtain an amphiphilic cross-linking agent.

[0061] The temperature of the ice bath was 0°C.

[0062] The molar ratio of the long carbon chain di-isomerized aliphatic diol polyoxyethylene ether, triethylamine and acryloyl chloride is 10:13:18; the mass ratio of the long carbon chain di-isomerized aliphatic diol polyoxyethylene ether and dichloromethane is 1:10.

[0063] The stirring rate is 400 r / min.

[0064] The dropping rate of the acryloyl chloride was 18 ml / min.

[0065] S2. Preparation of modified sandalwood essential oil β-cyclodextrin coating

[0066] S21, adding β-cyclodextrin to deionized water, heating and stirring until completely dissolved, to obtain a β-cyclodextrin solution;

[0067] S22, adding sandalwood essential oil and an amphiphilic cross-linking agent to anhydrous ethanol, stirring and dissolving at room temperature to obtain an ethanol solution of sandalwood essential oil;

[0068] S23, adding the ethanol solution of sandalwood essential oil to the β-cyclodextrin solution to obtain a mixed solution;

[0069] S24, adding the mixed solution to a jacketed homogenizer for homogenization, precipitating at low temperature, filtering, washing with petroleum ether, and drying to obtain a sandalwood essential oil β-cyclodextrin coating;

[0070] S25. The sandalwood essential oil β-cyclodextrin coating is subjected to ultraviolet irradiation treatment to obtain a modified sandalwood essential oil β-cyclodextrin coating having a cross-linked structure inside, with a coating rate of 88.7%.

[0071] The temperature of the heating and stirring in S21 is 70° C., and the mass concentration of the β-cyclodextrin solution is 10%.

[0072] The volume ratio of sandalwood essential oil to anhydrous ethanol in S22 is 1:6.

[0073] The amount of the amphiphilic cross-linking agent added in S22 is 4% of the mass of the sandalwood essential oil.

[0074] The mass ratio of the sandalwood essential oil in the S23 sandalwood essential oil ethanol solution to the β-cyclodextrin in the β-cyclodextrin solution is 1:5.

[0075] The homogenization treatment in S24 is performed for 80 minutes at a temperature of 20° C. and a rotation speed of 4000 r / min. The homogenization treatment can improve the uniformity of the particle size of the coated material.

[0076] The temperature of the low-temperature precipitation in S24 is 2°C.

[0077] The temperature of the ultraviolet light treatment in S25 is 55° C. and the light intensity is 25 mW / cm 2 , wavelength is 365nm, and time is 45min.

[0078] S3. Preparation of coating emulsion

[0079] The modified sandalwood essential oil β-cyclodextrin coating was added to deionized water and stirred for 20 minutes, then a butter acrylic thickener was added and stirred for 8 minutes, and sodium hydroxide solution was added and stirred to adjust the pH to 9 to obtain a coating emulsion with D90 <2.0 μm and PDI <0.3.

[0080] The added amount of the modified sandalwood essential oil β-cyclodextrin coating is 18% of the mass of deionized water, and the added amount of the butter acrylic thickener is 3% of the mass of deionized water.

[0081] The mass fraction of the sodium hydroxide solution is 12%.

[0082] S4. Preparation of blended spinning solution

[0083] Cotton pulp is used as raw material, and viscose spinning solution is prepared through the processes of impregnation, pressing, crushing, aging, yellowing, dissolving, filtering, degassing and the like; the coating emulsion is added into the viscose spinning solution in proportion before spinning and mixed evenly to prepare a blended spinning solution.

[0084] The cellulose spinning solution has a viscosity of 65 s (falling ball method), a maturity of 16 mL (15% NH 4 CL), a methyl cellulose content of 7 wt %, and a sodium hydroxide content of 4.8 wt %.

[0085] The added amount of the coating emulsion is 7wt% of the modified sandalwood essential oil β-cyclodextrin coating in the coating emulsion based on the content of the methyl cellulose.

[0086] S5, Spinning

[0087] After the blended spinning solution is ejected from the spinneret, it is formed and drawn in a coagulation bath to obtain a primary fiber bundle. The bundle is further formed in the second bath, enters the third bath for plasticization and drawing, and then enters the post-processing process after being cut.

[0088] In the coagulation bath, sulfuric acid is 25 g / L, sodium sulfate is 50 g / L, zinc sulfate is 0.6 g / L, the temperature is 28°C, and the draft is -10%; in the second bath, sulfuric acid is 15 g / L, sodium sulfate is 25 g / L, the temperature is 32°C, and the draft is 60%; in the third bath, sulfuric acid is 18 g / L, the temperature is 90°C, and the draft is 17%; the spinning rate is 35 m / min.

[0089] S6. Post-processing

[0090] The cut fiber bundles are washed, desulfurized, bleached, oiled and dried to obtain sandalwood cellulose fibers.

[0091] Example 2: A method for preparing sandalwood cellulose fiber, the preparation method comprising the following steps:

[0092] S1. Preparation of amphiphilic cross-linking agent

[0093] Add long-chain di-isomerized aliphatic diol polyoxyethylene ether and triethylamine to dichloromethane in an ice bath and stir for 30 minutes. Then add acryloyl chloride dropwise and stir for 3 hours after the addition is complete. Then heat to 25°C and stir to react for 12 hours. After the reaction is completed, filter under reduced pressure and rotary evaporate to obtain the product. Dissolve the product with an appropriate amount of ether and continue to filter under reduced pressure and rotary evaporate to obtain an amphiphilic crosslinker.

[0094] The temperature of the ice bath was 5°C.

[0095] The molar ratio of the long carbon chain di-isomerized aliphatic diol polyoxyethylene ether, triethylamine and acryloyl chloride is 9:12:16; the mass ratio of the long carbon chain di-isomerized aliphatic diol polyoxyethylene ether and dichloromethane is 1:10.

[0096] The stirring rate is 300 r / min.

[0097] The dropping rate of the acryloyl chloride was 15 ml / min.

[0098] S2. Preparation of modified sandalwood essential oil β-cyclodextrin coating

[0099] S21, adding β-cyclodextrin to deionized water, heating and stirring until completely dissolved, to obtain a β-cyclodextrin solution;

[0100] S22, adding sandalwood essential oil and an amphiphilic cross-linking agent to anhydrous ethanol, stirring and dissolving at room temperature to obtain an ethanol solution of sandalwood essential oil;

[0101] S23, adding the ethanol solution of sandalwood essential oil to the β-cyclodextrin solution to obtain a mixed solution;

[0102] S24, adding the mixed solution to a jacketed homogenizer for homogenization, precipitating at low temperature, filtering, washing with petroleum ether, and drying to obtain a sandalwood essential oil β-cyclodextrin coating;

[0103] S25. The sandalwood essential oil β-cyclodextrin coating was subjected to ultraviolet irradiation treatment to obtain a modified sandalwood essential oil β-cyclodextrin coating having a cross-linked structure inside, with a coating rate of 86.1%.

[0104] The temperature of the heating and stirring in S21 is 65° C., and the mass concentration of the β-cyclodextrin solution is 8%.

[0105] The volume ratio of sandalwood essential oil to anhydrous ethanol in S22 is 1:4.

[0106] The amount of the amphiphilic cross-linking agent added in S22 is 3% of the mass of the sandalwood essential oil.

[0107] The mass ratio of the sandalwood essential oil in the S23 sandalwood essential oil ethanol solution to the β-cyclodextrin in the β-cyclodextrin solution is 1:10.

[0108] The homogenization treatment in S24 is performed for 60 minutes at a temperature of 18° C. and a rotation speed of 3000 r / min. The homogenization treatment can improve the uniformity of the particle size of the coated material.

[0109] The temperature of the low-temperature precipitation in S24 is 5°C.

[0110] The temperature of the ultraviolet light treatment in S25 is 50° C. and the light intensity is 20 mW / cm 2 , wavelength is 365nm, and time is 40min.

[0111] S3. Preparation of coating emulsion

[0112] The modified sandalwood essential oil β-cyclodextrin coating was added to deionized water and stirred for 15 minutes, then a butter acrylic thickener was added and stirred for 5 minutes, and sodium hydroxide solution was added and stirred to adjust the pH to 8 to obtain a coating emulsion with D90 <2.0 μm and PDI <0.3.

[0113] The added amount of the modified sandalwood essential oil β-cyclodextrin coating is 15% of the mass of deionized water, and the added amount of the butter acrylic thickener is 2% of the mass of deionized water.

[0114] The mass fraction of the sodium hydroxide solution is 10%.

[0115] S4. Preparation of blended spinning solution

[0116] Cotton pulp is used as raw material, and viscose spinning solution is prepared through the processes of impregnation, pressing, crushing, aging, yellowing, dissolving, filtering, degassing and the like; the coating emulsion is added into the viscose spinning solution in proportion before spinning and mixed evenly to prepare a blended spinning solution.

[0117] The cellulose spinning solution has a viscosity of 50 s (falling ball method), a maturity of 12 mL (15% NH 4 CL), a methyl cellulose content of 6.8 wt %, and a sodium hydroxide content of 4.5 wt %.

[0118] The added amount of the coating emulsion is 5wt% of the modified sandalwood essential oil β-cyclodextrin coating in the coating emulsion based on the content of the methyl cellulose.

[0119] S5, Spinning

[0120] After the blended spinning solution is ejected from the spinneret, it is formed and drawn in a coagulation bath to obtain a primary fiber bundle. The bundle is further formed in the second bath, enters the third bath for plasticization and drawing, and then enters the post-processing process after being cut.

[0121] In the coagulation bath, sulfuric acid is 20 g / L, sodium sulfate is 40 g / L, zinc sulfate is 1 g / L, the temperature is 25°C, and the draft is -20%; in the second bath, sulfuric acid is 10 g / L, sodium sulfate is 30 g / L, the temperature is 30°C, and the draft is 50%; in the third bath, sulfuric acid is 15 g / L, the temperature is 85°C, and the draft is 15%; the spinning rate is 30 m / min.

[0122] S6. Post-processing

[0123] The cut fiber bundles are washed, desulfurized, bleached, oiled and dried to obtain sandalwood cellulose fibers.

[0124] Example 3: A method for preparing sandalwood cellulose fiber, the preparation method comprising the following steps:

[0125] S1. Preparation of amphiphilic cross-linking agent

[0126] Add long-chain di-isomerized aliphatic diol polyoxyethylene ether and triethylamine to dichloromethane in an ice bath and stir for 40 minutes. Then add acryloyl chloride dropwise and stir for 4 hours after the addition is complete. Then heat to 30°C and stir to react for 14 hours. After the reaction is completed, filter under reduced pressure and rotary evaporate to obtain the product. Dissolve the product with an appropriate amount of ether and continue to filter under reduced pressure and rotary evaporate to obtain an amphiphilic cross-linking agent.

[0127] The temperature of the ice bath was 0°C.

[0128] The molar ratio of the long carbon chain di-isomerized aliphatic diol polyoxyethylene ether, triethylamine and acryloyl chloride is 11:14:20; the mass ratio of the long carbon chain di-isomerized aliphatic diol polyoxyethylene ether and dichloromethane is 1:10.

[0129] The stirring rate is 600 r / min.

[0130] The dropping rate of the acryloyl chloride was 20 ml / min.

[0131] S2. Preparation of modified sandalwood essential oil β-cyclodextrin coating

[0132] S21, adding β-cyclodextrin to deionized water, heating and stirring until completely dissolved, to obtain a β-cyclodextrin solution;

[0133] S22, adding sandalwood essential oil and an amphiphilic cross-linking agent to anhydrous ethanol, stirring and dissolving at room temperature to obtain an ethanol solution of sandalwood essential oil;

[0134] S23, adding the ethanol solution of sandalwood essential oil to the β-cyclodextrin solution to obtain a mixed solution;

[0135] S24, adding the mixed solution to a jacketed homogenizer for homogenization, precipitating at low temperature, filtering, washing with petroleum ether, and drying to obtain a sandalwood essential oil β-cyclodextrin coating;

[0136] S25. The sandalwood essential oil β-cyclodextrin coating is subjected to ultraviolet irradiation treatment to obtain a modified sandalwood essential oil β-cyclodextrin coating having a cross-linked structure inside, with a coating rate of 87.5%.

[0137] The temperature of the heating and stirring in S21 is 75° C., and the mass concentration of the β-cyclodextrin solution is 12%.

[0138] The volume ratio of sandalwood essential oil to anhydrous ethanol in S22 is 1:10.

[0139] The amount of the amphiphilic cross-linking agent added in S22 is 5% of the mass of the sandalwood essential oil.

[0140] The mass ratio of the sandalwood essential oil in the S23 sandalwood essential oil ethanol solution to the β-cyclodextrin in the β-cyclodextrin solution is 1:10.

[0141] The homogenization treatment in S24 is performed for 90 minutes at a temperature of 23° C. and a rotation speed of 3500 r / min. The homogenization treatment can improve the uniformity of the particle size of the coated material.

[0142] The temperature of the low-temperature precipitation in S24 is 0°C.

[0143] The temperature of the ultraviolet light treatment in S25 is 60° C. and the light intensity is 30 mW / cm 2 , wavelength is 365nm, and time is 50min.

[0144] S3. Preparation of coating emulsion

[0145] The modified sandalwood essential oil β-cyclodextrin coating was added to deionized water and stirred for 25 minutes, then a butter acrylic thickener was added and stirred for 10 minutes, and sodium hydroxide solution was added and stirred to adjust the pH to 10 to obtain a coating emulsion with D90 <2.0 μm and PDI <0.3.

[0146] The added amount of the modified sandalwood essential oil β-cyclodextrin coating is 20% of the mass of deionized water, and the added amount of the butter acrylic thickener is 4% of the mass of deionized water.

[0147] The mass fraction of the sodium hydroxide solution is 13%.

[0148] S4. Preparation of blended spinning solution

[0149] Cotton pulp is used as raw material, and viscose spinning solution is prepared through the processes of impregnation, pressing, crushing, aging, yellowing, dissolving, filtering, degassing and the like; the coating emulsion is added into the viscose spinning solution in proportion before spinning and mixed evenly to prepare a blended spinning solution.

[0150] The cellulose spinning solution has a viscosity of 70 s (falling ball method), a maturity of 18 mL (15% NH 4 CL), a methyl cellulose content of 7.2 wt %, and a sodium hydroxide content of 5.2 wt %.

[0151] The added amount of the coating emulsion is 8wt% of the modified sandalwood essential oil β-cyclodextrin coating in the coating emulsion based on the content of the methyl cellulose.

[0152] S5, Spinning

[0153] After the blended spinning solution is ejected from the spinneret, it is formed and drawn in a coagulation bath to obtain a primary fiber bundle. The bundle is further formed in the second bath, enters the third bath for plasticization and drawing, and then enters the post-processing process after being cut.

[0154] In the coagulation bath, sulfuric acid is 30 g / L, sodium sulfate is 60 g / L, zinc sulfate is 0.2 g / L, the temperature is 30°C, and the draft is 0%; in the second bath, sulfuric acid is 20 g / L, sodium sulfate is 20 g / L, the temperature is 35°C, and the draft is 80%; in the third bath, sulfuric acid is 20 g / L, the temperature is 95°C, and the draft is 20%; the spinning rate is 40 m / min.

[0155] S6. Post-processing

[0156] The cut fiber bundles are washed, desulfurized, bleached, oiled and dried to obtain sandalwood cellulose fibers.

[0157] Comparative Example 1: Representative Example 1 was selected, and the amphiphilic cross-linking agent in S22 and step S25 were removed. The rest were consistent with Example 1, as Comparative Example 1.

[0158] Comparative Example 2: Select the representative Example 1, remove the butter acrylic thickener in S3, and the rest are consistent with Example 1, as Comparative Example 2.

[0159] Comparative Example 3: Representative Example 1 was selected, and the coating emulsion was not added in step S4. After the fiber was formed and then finished, the fiber was immersed in the coating emulsion for 24 hours and dried, as Comparative Example 3.

[0160] Comparative Example 4: Representative Example 1 was selected, and the sulfuric acid in the coagulation bath in S5 was 110 g / L, the sodium sulfate was 340 g / L, the zinc sulfate was 11 g / L, the temperature was 48°C, the drafts were 52%, 55% and 8% respectively, and the rest were consistent with Example 1, as Comparative Example 4.

[0161] After washing fifty times with water, the sandalwood cellulose fibers prepared in Examples 1-3 showed an antibacterial rate of more than 90% against Staphylococcus aureus and Escherichia coli (measured in accordance with GB / T 20944.3-2008), and a mite repellency rate of more than 60% (measured in accordance with the repellency method of GB / T 24253-2009 / 9.1), demonstrating excellent antibacterial and anti-mite effects.

[0162] The fibers prepared in Examples 1-3 and Comparative Examples 1-4 were tested for properties such as strength, moisture absorption, and stability of active ingredients, as shown in Table 1.

[0163] Table 1

[0164]

[0165] As can be seen from Table 1, the sandalwood cellulose fibers prepared using Examples 1-3 not only have good mechanical properties, but also have excellent hygroscopicity. After multiple washings, they still retain more effective components of sandalwood essential oil and have a longer action time.

[0166] In Comparative Example 1, no amphiphilic crosslinking agent was used, and the mechanical properties of the fiber remained basically unchanged. After fifty washes, the loss rate of the effective ingredient of the sandalwood essential oil was high, indicating that the modified sandalwood essential oil β-cyclodextrin coating with an internal cross-linked structure had a better sustained-release effect and was not easily released too quickly after washing.

[0167] In Comparative Example 2, the butter acrylic thickener in S3 was removed, and the mechanical properties and hygroscopicity of the fiber decreased slightly, indicating that the butter acrylic thickener promoted the stability and compatibility of the sustained release of the modified sandalwood essential oil β-cyclodextrin coating in the system. Therefore, the mechanical properties of the fiber in Example 1 were better; the butter acrylic thickener itself has a good moisturizing effect, so the moisture regain of Example 1 is also larger.

[0168] Comparative Example 3 adopts the post-finishing method, and the water washing loss rate of the effective ingredients of sandalwood essential oil increases significantly. This is because the post-finishing method causes the coating to mostly adhere to the fiber surface, and the water washing effect is poor.

[0169] In Comparative Example 4, the second and third coagulation baths were not used, and the mechanical properties of the fiber decreased. The washing loss rate of sandalwood essential oil was slightly higher than that of Example 1, indicating that the three coagulation baths further delayed the fiber formation, made the combination of the fiber and the coating more stable, and the additives were more resistant to washing.

[0170] Unless otherwise specified, the ratios and percentages described in the present invention are all by mass; all raw materials are commercially available.

[0171] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing sandalwood cellulose fiber, characterized in that: The preparation method includes the preparation of an amphiphilic cross-linking agent, the preparation of a modified sandalwood essential oil β-cyclodextrin coating, the preparation of a coating emulsion, the preparation of a blended spinning solution, spinning molding and post-processing; The preparation method of the modified sandalwood essential oil β-cyclodextrin coating is as follows: S21, adding β-cyclodextrin to deionized water, heating and stirring until completely dissolved, to obtain a β-cyclodextrin solution; S22, adding sandalwood essential oil and an amphiphilic cross-linking agent to anhydrous ethanol, stirring and dissolving at room temperature to obtain an ethanol solution of sandalwood essential oil; S23, adding the ethanol solution of sandalwood essential oil to the β-cyclodextrin solution to obtain a mixed solution; S24, adding the mixed solution to a jacketed homogenizer for homogenization, precipitating at low temperature, filtering, washing with petroleum ether, and drying to obtain a sandalwood essential oil β-cyclodextrin coating; S25, subjecting the sandalwood essential oil β-cyclodextrin coating to ultraviolet irradiation treatment to obtain a modified sandalwood essential oil β-cyclodextrin coating having a cross-linked structure inside; The coating emulsion is prepared by adding the modified sandalwood essential oil β-cyclodextrin coating to deionized water and stirring for 15 to 25 minutes, then adding a butter acrylic thickener and continuing to stir for 5 to 10 minutes, adding a sodium hydroxide solution and stirring to adjust the pH to 8 to 10, to obtain a coating emulsion with D90 less than 2.0 μm and PDI less than 0.3; The spinning process is as follows: the blended spinning solution is ejected from the spinneret, and then formed and drawn in a coagulation bath to obtain a primary fiber bundle. The bundle is further formed in a second bath, enters a third bath for plasticization and drawing, and then enters a post-processing process after being cut; In the coagulation bath, sulfuric acid is 20-30 g / L, sodium sulfate is 40-60 g / L, zinc sulfate is 0.2-1 g / L, the temperature is 25-30° C., and the draft is -20-0%; in the second bath, sulfuric acid is 10-20 g / L, sodium sulfate is 20-30 g / L, the temperature is 30-35° C., and the draft is 50-80%; in the third bath, sulfuric acid is 15-20 g / L, the temperature is 85-95° C., and the draft is 15-20%.

2. The method for preparing sandalwood cellulose fiber according to claim 1, wherein: The amphiphilic crosslinking agent is prepared by adding long carbon chain di-isomerized aliphatic diol polyoxyethylene ether and triethylamine to dichloromethane under ice bath conditions and stirring for 30-40 minutes, then dropwise adding acryloyl chloride, stirring for 3-4 hours after the dropwise addition is complete, then heating to 25-30° C. and stirring for 12-14 hours, after which the reaction is completed, filtering under reduced pressure and rotary evaporation are performed to obtain a product, dissolving the product with an appropriate amount of ether, and then continuing to filter under reduced pressure and rotary evaporation to obtain the amphiphilic crosslinking agent.

3. The method for preparing sandalwood cellulose fiber according to claim 2, characterized in that: The temperature of the ice bath is 0-5°C; The molar ratio of the long carbon chain di-isomerized aliphatic diol polyoxyethylene ether, triethylamine and acryloyl chloride is 9-11:12-14:16-20; The stirring rate is 300-600 r / min; The dropping rate of the acryloyl chloride is 15-20 ml / min.

4. The method for preparing sandalwood cellulose fiber according to claim 1, characterized in that: The temperature of the heating and stirring in S21 is 65-75° C., and the mass concentration of the β-cyclodextrin solution is 8-12%; The volume ratio of sandalwood essential oil to anhydrous ethanol in S22 is 1:1-10; The amount of the amphiphilic cross-linking agent added in S22 is 3-5% of the mass of the sandalwood essential oil; The mass ratio of the sandalwood essential oil in the ethanol solution of the S23 sandalwood essential oil to the β-cyclodextrin in the β-cyclodextrin solution is 1:5-10; The homogenization process in S24 is performed for 60 to 90 minutes, at a temperature of 18 to 23° C., and at a rotation speed of 3000 to 4000 r / min. The temperature of the low-temperature precipitation in S24 is 0-5°C; The temperature of the ultraviolet light treatment in S25 is 50-60° C., and the light intensity is 20-30 mW / cm 2 , wavelength is 365nm, time is 40 to 50 minutes.

5. The method for preparing sandalwood cellulose fiber according to claim 1, characterized in that: The amount of the modified sandalwood essential oil β-cyclodextrin coating added is 15-20% of the mass of deionized water, and the amount of the butter acrylic thickener added is 2-4% of the mass of deionized water; The mass fraction of the sodium hydroxide solution is 10-13%.

6. The method for preparing sandalwood cellulose fiber according to claim 1, characterized in that: The blended spinning solution is prepared by selecting cotton pulp, wood pulp, bamboo pulp or a mixture thereof as raw materials, and preparing a viscose spinning solution through the steps of impregnation, pressing, crushing, aging, yellowing, dissolving, filtering and degassing; and adding the coating emulsion into the viscose spinning solution in proportion before spinning and mixing them evenly to prepare the blended spinning solution. The addition amount of the coating emulsion is 5-8wt% of the modified sandalwood essential oil β-cyclodextrin coating in the coating emulsion based on the content of the methyl cellulose in the viscose spinning solution.

7. The method for preparing sandalwood cellulose fiber according to claim 1, characterized in that: The post-processing is to wash, desulfurize, bleach, oil and dry the cut fiber bundles to obtain sandalwood cellulose fibers.

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