A preparation method of antibacterial essential oil microcapsules and application in washing powder

Abstract

The present invention relates to the technical field of microcapsules, and discloses a method for preparing an antibacterial essential oil microcapsule and its application in washing powder. The present invention uses ethylenediaminetetraacetic acid dianhydride, N, N-dimethylethylenediamine, glycidyl methacrylate, etc. as reactions, prepares a diquaternary ammonium salt diacrylate monomer of a quaternary ammonium salt group, and then undergoes a graft polymerization reaction with acryloyl-β-cyclodextrin, and introduces a large amount of diquaternary ammonium salt antibacterial groups into cyclodextrin microcapsules, showing excellent antibacterial properties. The antibacterial cyclodextrin microcapsules have a porous cross-linked network, a larger specific surface area, can provide more inclusion sites, and improve the inclusion amount of microcapsules to essential oils such as orange peel. There is a good application prospect in the washing products such as aromatic washing powder and laundry detergent.

Description

Technical Field

[0001] The invention relates to the technical field of microcapsules, in particular to a method for preparing antibacterial essential oil microcapsules and application of the microcapsules in washing powder. Background Art

[0002] Plant essential oils such as orange peel and jasmine have a pleasant aroma and are widely used in washing powder, laundry detergent, dishwashing liquid and other toiletries. However, plant essential oils are volatile and lose a lot during storage and use. In addition, plant essential oils are usually oily liquids, which is not conducive to their practical application in solid products such as laundry detergent. Using microcapsules to contain plant essential oils can reduce the volatility of essential oils and slowly release the fragrance of essential oils.

[0003] β-cyclodextrin is a natural and safe sugar-based compound, and many compounds have molecular recognition and inclusion complexes, and can be made into microcapsules, which have important applications in the fields of toiletries, medical drugs, etc. Patent CN108531298B discloses a washing powder containing golden bergamot essential oil microcapsules and its preparation method, which uses β-cyclodextrin, golden bergamot essential oil, etc. as raw materials to prepare golden bergamot essential oil microcapsules: adding them to washing powder allows the essential oil to exert its long-lasting fragrance in the product, and at the same time the product brings a pleasant and fragrant sensory experience. However, the essential oil microcapsules do not have antibacterial properties and cannot give the washing powder excellent antibacterial and sterilization effects. Summary of the invention

[0004] Technical Problems Solved by the Invention The problem that traditional essential oil microcapsules do not have antibacterial properties and the problem that the microcapsules have a low essential oil loading capacity.

[0005] The technical solution of the present invention is: a method for preparing antibacterial essential oil microcapsules:

[0006] Step (1), adding water, acryloyl-β-cyclodextrin, and diquaternary ammonium salt diacrylate monomer into a reaction bottle, stirring and mixing, introducing nitrogen, adding ammonium persulfate and sodium bisulfite, filtering after reaction, washing with ethanol, placing in a dialysis bag, dialyzing with distilled water, and drying to obtain antibacterial cyclodextrin microcapsules.

[0007] The structural formula of the diquaternary ammonium salt diacrylate monomer is shown in formula (I):

[0008]

[0009] Step (2), adding water, plant essential oil and emulsifier into the reaction bottle, stirring and mixing, adding antibacterial cyclodextrin microcapsules, stirring for inclusion, filtering, washing with distilled water, and drying to obtain antibacterial essential oil microcapsules.

[0010] Furthermore, in step (1), the mass ratio of acryloyl-β-cyclodextrin, diquaternary ammonium diacrylate monomer, ammonium persulfate, and sodium bisulfite is 100:(5-20):(0.04-0.18):(0.016-0.068).

[0011] Furthermore, in step (1), the reaction temperature is 50-60° C. and the reaction time is 12-18 h.

[0012] Furthermore, in step (2), the mass ratio of plant essential oil to antibacterial cyclodextrin microcapsules is (10-60):100.

[0013] Furthermore, in step (2), the temperature during inclusion is 40-60° C. and the time is 2-3 h.

[0014] Furthermore, the plant essential oils include rose essential oil, jasmine essential oil, and orange peel essential oil.

[0015] Further, step S1, add N,N-dimethylformamide solvent, ethylenediaminetetraacetic acid dianhydride, N,N-dimethylethylenediamine to the reaction bottle, introduce nitrogen, react at 60-75° C. for 12-18 hours, distill the solution under reduced pressure, and recrystallize the product with ethanol to obtain intermediate 1. The reaction formula is:

[0016]

[0017] Step S2, add isopropanol, intermediate 1, and hydrochloric acid solution to the reaction bottle, add glycidyl methacrylate after stirring, introduce nitrogen, react at 65-75° C. for 2-4 hours, rotary evaporate the solution, wash the product with petroleum ether, and recrystallize with ethanol to obtain a diquaternary ammonium diacrylate monomer. The reaction formula is:

[0018]

[0019] Furthermore, in step S1, the molar ratio of ethylenediaminetetraacetic dianhydride to N,N-dimethylethylenediamine is 1:(2.1-2.2).

[0020] Furthermore, the molar ratio of the intermediate 1 to glycidyl methacrylate is 1:(2.2-2.5).

[0021] Furthermore, the antibacterial essential oil microcapsules are used in antibacterial laundry detergent, which includes 70-75 parts by weight of industrial salt, 4.5-5.5 parts by weight of alkaline protease blue particles, 1.2-1.8 parts by weight of protease, 16-20 parts by weight of sodium carbonate, 2.5-3.4 parts by weight of fatty alcohol polyoxyethylene ether AEO-9, 2.5-3.6 parts by weight of sodium α-olefin sulfonate, and 1-6 parts by weight of antibacterial essential oil microcapsules.

[0022] Technical effect of the invention: The invention uses cheap and readily available ethylenediaminetetraacetic acid dianhydride, N,N-dimethylethylenediamine, glycidyl methacrylate and the like as reactions to prepare a novel diquaternary ammonium diacrylate monomer containing two alkenyl groups and two quaternary ammonium salt groups.

[0023] The acryloyl-β-cyclodextrin of the present invention undergoes graft polymerization reaction with diquaternary ammonium salt diacrylate monomers, and a large amount of diquaternary ammonium salt antibacterial groups are introduced into the cyclodextrin microcapsules. The diquaternary ammonium salt groups have strong positive charge and can interact electrostatically with the negatively charged cell membrane of bacteria, thereby changing the permeability of the cell membrane, causing the enzyme and other genetic materials in the cell membrane to flow out, inhibiting the normal metabolism and reproduction of bacteria, thereby achieving excellent bactericidal effect. The highest antibacterial rates against Escherichia coli, Staphylococcus aureus and Candida albicans reach 99.99%, 99.99% and 99.23%, respectively, showing excellent antibacterial performance.

[0024] The beta-cyclodextrin in the antibacterial cyclodextrin microcapsule of the present invention has a cavity structure that is hydrophobic inside and hydrophilic outside, has good inclusion effect on essential oil, and the diquaternary ammonium salt diacrylate monomer contains two alkenyl groups, can react crosslinking polymerization with the alkenyl group of acryloyl-beta-cyclodextrin, the formed microcapsule has a porous crosslinked network, and the specific surface area is larger, more inclusion sites can be provided, thereby improving the inclusion amount of microcapsule to essential oil. And the diquaternary ammonium salt diacrylate contains hydrophilic groups such as multiple carboxyls, hydroxyls, quaternary ammonium salts, is introduced into the cyclodextrin microcapsule matrix, now improves the hydrophilicity of microcapsule, and the better the wettability and dispersibility in water, the more conducive to improving the inclusion amount of microcapsule. The embedding amount to the essential oils such as orange peel, rose, jasmine reaches 0.067-0.384g / g. When added to washing powder and other cleaning products, it can give them good antibacterial and bactericidal effects, and has the function of slowly releasing the aromatic odor of plant essential oils. It has good application prospects in aromatic washing powder, laundry detergent and other cleaning products. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] Add 150 mL of N,N-dimethylformamide, 5 g of β-cyclodextrin, and 2.6 g of triethylamine to the reaction bottle, introduce nitrogen after stirring, add 2.3 g of acryloyl chloride in an ice water bath, stir for 30 min, then react at 25 ° C for 1 h, let stand and filter, distill the filtrate under reduced pressure, wash with acetone, and dry to obtain acryloyl-β-cyclodextrin.

[0027] The antibacterial laundry detergent is composed of 700-750g of industrial salt (mainly sodium chloride), 45-55g of alkaline protease blue particles, 12-18g of protease (model Savinase 8.0T), 160-200g of sodium carbonate, 25-34g of fatty alcohol polyoxyethylene ether AEO-9, 25-36g of α-olefin sodium sulfonate and 10-60g of antibacterial essential oil microcapsules.

[0028] Example 1

[0029] (1) Add 30 mL of N,N-dimethylformamide solvent, 10 mmol of ethylenediaminetetraacetic anhydride, and 21 mmol of N,N-dimethylethylenediamine into a reaction flask, introduce nitrogen, and react at 65°C for 18 h. Distill the solution under reduced pressure, and recrystallize the product with ethanol to obtain intermediate 1.

[0030] (2) Add 80 mL of isopropanol, 20 mmol of intermediate 1, and 40 mL of hydrochloric acid solution (2 mol / L) into the reaction flask, add 50 mmol of glycidyl methacrylate after stirring, introduce nitrogen, react at 65° C. for 4 h, and rotary evaporate the solution. After washing the product with petroleum ether, recrystallize it with ethanol to obtain a diquaternary ammonium diacrylate monomer.

[0031] (3) Add 200 mL of water, 50 g of acryloyl-β-cyclodextrin, and 2.5 g of diquaternary ammonium diacrylate monomer to the reaction bottle, stir and mix well, then introduce nitrogen, add 0.02 g of ammonium persulfate and 0.08 g of sodium bisulfite, react at 60 ° C for 12 h, filter, wash with ethanol, place in a dialysis bag, dialyze with distilled water, and dry to obtain antibacterial cyclodextrin microcapsules.

[0032] Example 2

[0033] (1) Add 30 mL of N,N-dimethylformamide solvent, 10 mmol of ethylenediaminetetraacetic anhydride, and 22 mmol of N,N-dimethylethylenediamine into a reaction flask, introduce nitrogen, and react at 60°C for 18 h. Distill the solution under reduced pressure, and recrystallize the product with ethanol to obtain intermediate 1.

[0034] (2) Add 50 mL of isopropanol, 20 mmol of intermediate 1, and 30 mL of hydrochloric acid solution (3 mol / L) into the reaction flask, stir, add 48 mmol of glycidyl methacrylate, introduce nitrogen, react at 75° C. for 2 h, rotary evaporate the solution, wash the product with petroleum ether, and recrystallize with ethanol to obtain a diquaternary ammonium diacrylate monomer.

[0035] (3) Add 300 mL of water, 50 g of acryloyl-β-cyclodextrin, and 6 g of diquaternary ammonium diacrylate monomer to the reaction bottle, stir and mix well, then introduce nitrogen, add 0.05 g of ammonium persulfate and 0.15 g of sodium bisulfite, react at 50 ° C for 18 h, filter, wash with ethanol, place in a dialysis bag, dialyze with distilled water, and dry to obtain antibacterial cyclodextrin microcapsules.

[0036] Example 3

[0037] (1) Add 25 mL of N,N-dimethylformamide solvent, 10 mmol of ethylenediaminetetraacetic dianhydride, and 21 mmol of N,N-dimethylethylenediamine into a reaction flask, introduce nitrogen, and react at 75°C for 12 h. Distill the solution under reduced pressure, and recrystallize the product with ethanol to obtain intermediate 1.

[0038] (2) Add 60 mL of isopropanol, 20 mmol of intermediate 1, and 40 mL of hydrochloric acid solution (2 mol / L) into the reaction flask, stir, add 44 mmol of glycidyl methacrylate, introduce nitrogen, react at 70° C. for 2 h, rotary evaporate the solution, wash the product with petroleum ether, and recrystallize with ethanol to obtain a diquaternary ammonium diacrylate monomer.

[0039] (3) Add 400 mL of water, 50 g of acryloyl-β-cyclodextrin, and 10 g of diquaternary ammonium diacrylate monomer to the reaction bottle, stir and mix well, then introduce nitrogen, add 0.09 g of ammonium persulfate and 0.024 g of sodium bisulfite, react at 55 ° C for 18 h, filter, wash with ethanol, place in a dialysis bag, dialyze with distilled water, and dry to obtain antibacterial cyclodextrin microcapsules.

[0040] In Comparative Example 1, acryloyl-β-cyclodextrin was used as the cyclodextrin microcapsule.

[0041] Comparative Example 2

[0042] The difference between this comparative example and Example 1 is that ethylene glycol dimethacrylate is used instead of the diquaternary ammonium salt diacrylate monomer.

[0043] (1) Add 400 mL of water, 50 g of acryloyl-β-cyclodextrin, and 10 g of ethylene glycol dimethacrylate to a reaction bottle, stir and mix, then introduce nitrogen, add 0.09 g of ammonium persulfate and 0.024 g of sodium bisulfite, react at 55° C. for 18 h, filter, wash with ethanol, place in a dialysis bag, dialyze with distilled water, and dry to obtain cyclodextrin microcapsules.

[0044] Transfer the slant-preserved strains of Escherichia coli, Staphylococcus aureus, and Candida albicans to the surface of the plate agar medium, and activate them at 37°C for 24 hours; use an inoculation loop to scrape 2 loops of fresh bacteria into the culture medium, and make 10-fold incremental dilutions. Take a concentration of 106 The dilution with the highest cfu / mL was used as the test bacterial solution.

[0045] Pipette 0.2mL of the test bacterial solution and drop it on the cyclodextrin microcapsules, and lay the sterilized polyethylene covering film flat on the surface of the cyclodextrin microcapsules. Take the cyclodextrin microcapsules (acryloyl-β-cyclodextrin) of comparative example 1 as the blank control sample. Place it in a culture dish and culture it at 37°C for 24h. Use 20mL of 0.8% sodium chloride solution as the eluent to elute the cyclodextrin microcapsules and the polyethylene covering film. Then take 0.5mL of the eluate, inoculate it in an agar medium, and culture it at 37°C for 48h. After culture, perform the live bacteria technique. Calculate the antibacterial rate R. R = (BC) / B × 100%. B is the average number of recovered bacteria in the blank control sample (cfu / piece). C is the average number of recovered bacteria in the experimental sample control sample (cfu / piece).

[0046] Table 1 Antibacterial performance test of cyclodextrin microcapsules

[0047]

[0048] After testing, the antibacterial rates of the cyclodextrin microcapsules of Examples 1-3 against Escherichia coli, Staphylococcus aureus, and Candida albicans reached up to 99.99%, 99.99%, and 99.23%, respectively, showing excellent antibacterial properties. This is because acrylyl-β-cyclodextrin and diquaternary ammonium diacrylate monomers undergo graft polymerization, and a large number of diquaternary ammonium antibacterial groups are introduced into the cyclodextrin microcapsules. The diquaternary ammonium groups have strong positive charges and can interact electrostatically with the negatively charged cell membrane of bacteria, changing the permeability of the cell membrane, causing the enzymes and other genetic materials in the cell membrane to flow out, inhibiting the normal metabolism and reproduction of bacteria, thereby achieving excellent bactericidal effects.

[0049] Example 4

[0050] Add 400 mL of water, 5 g of orange peel essential oil, and 0.08 g of Tween 80 emulsifier to the reaction bottle, stir and mix, then add 50 g of antibacterial cyclodextrin microcapsules (prepared according to the method of Example 1), stir and carry out inclusion at 50° C. for 2 h, filter, wash with distilled water, dry, and obtain antibacterial essential oil microcapsules, which are then weighed.

[0051] Example 5

[0052] Add 600 mL of water, 20 g of rose essential oil, and 0.36 g of Tween 80 emulsifier into a reaction bottle, stir and mix, then add 50 g of antibacterial cyclodextrin microcapsules (prepared according to the method of Example 1), stir and carry out inclusion at 40° C. for 3 h, filter, wash with distilled water, dry, obtain antibacterial essential oil microcapsules, and weigh them.

[0053] Example 6

[0054] Add 600 mL of water, 30 g of jasmine essential oil, and 0.5 g of Tween 80 emulsifier into a reaction bottle, stir and mix, then add 50 g of antibacterial cyclodextrin microcapsules (prepared according to the method of Example 1), stir and carry out inclusion at 60° C. for 2 h, filter, wash with distilled water, dry, and obtain antibacterial essential oil microcapsules, which are then weighed.

[0055] Comparative Example 3

[0056] Add 400 mL of water, 5 g of orange peel essential oil, and 0.08 g of Tween 80 emulsifier to the reaction bottle, stir and mix, then add 50 g of cyclodextrin microcapsules (using acryloyl-β-cyclodextrin as cyclodextrin microcapsules), stir at 50°C for inclusion for 2 h, filter, wash with distilled water, dry, obtain essential oil microcapsules, and weigh.

[0057] Comparative Example 4

[0058] Add 400 mL of water, 5 g of orange peel essential oil, and 0.08 g of Tween 80 emulsifier to the reaction bottle, stir and mix, then add 50 g of cyclodextrin microcapsules (prepared according to the method of Comparative Example 2), stir and carry out inclusion at 50° C. for 2 h, filter, wash with distilled water, dry, obtain essential oil microcapsules, and weigh them.

[0059] Calculate the amount of essential oil encapsulated in the microcapsule W. W = (m-m0) / m0, where m is the mass of the essential oil microcapsule and m0 is the mass of the cyclodextrin microcapsule (without essential oil).

[0060] Table 2 Microencapsulation essential oil test

[0061] Embedding amount W(g / g) Example 4 0.067 Example 5 0.326 Example 6 0.384 Comparative Example 3 0.038 Comparative Example 4 0.054

[0062] After testing, the embedding amount of the antibacterial cyclodextrin microcapsules of embodiments 4-6 for essential oils such as orange peel reaches 0.067-0.384g / g, because β-cyclodextrin itself has a cavity structure that is hydrophobic inside and hydrophilic outside, and has a good inclusion effect on essential oils, and the diquaternary ammonium salt diacrylate monomer contains two alkenyl groups, which can undergo cross-linking polymerization with the alkenyl groups of acryloyl-β-cyclodextrin, and the formed microcapsules have a porous cross-linked network, a larger specific surface area, and can provide more inclusion sites, thereby increasing the inclusion amount of the microcapsules for essential oils. And the diquaternary ammonium salt diacrylate contains multiple hydrophilic groups such as carboxyl, hydroxyl, and quaternary ammonium salt, which are introduced into the cyclodextrin microcapsule matrix, and the hydrophilicity of the microcapsules is now improved, and the better the wettability and dispersibility in water, the better, which is conducive to increasing the inclusion amount of the microcapsules.

[0063] Comparative Example 3 uses acryloyl-β-cyclodextrin as cyclodextrin microcapsule, which does not undergo cross-linking reaction, does not contain porous cross-linked network, has low specific surface area, has fewer inclusion sites, and the inclusion amount of essential oil is only 0.038 g / g.

[0064] Comparative Example 4: Ethylene glycol dimethacrylate containing two alkenyl groups is cross-linked and polymerized with acryloyl-β-cyclodextrin to form microcapsules with porous cross-linked networks, larger specific surface area, more inclusion sites, and an inclusion amount of 0.054 g / g for essential oils, which is significantly higher than that of Comparative Example 3. However, it is slightly lower than that of Example 4, which may be because ethylene glycol dimethacrylate does not contain hydrophilic groups such as carboxyl, hydroxyl, and quaternary ammonium salts, and the hydrophilicity of the obtained cyclodextrin microcapsules is low, and the dispersibility in water is poor.

[0065] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in other forms. Any technician familiar with the profession may use the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes and apply them to other fields. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing antibacterial essential oil microcapsules, characterized in that: The preparation method is as follows: Step (1), adding water, acryloyl-β-cyclodextrin, and diquaternary ammonium salt diacrylate monomer into a reaction bottle, stirring and mixing, introducing nitrogen, adding ammonium persulfate and sodium bisulfite, filtering after reaction, washing with ethanol, placing in a dialysis bag, dialyzing with distilled water, and drying to obtain antibacterial cyclodextrin microcapsules; The structural formula of the diquaternary ammonium salt diacrylate monomer is shown in formula (I): Formula (I); Step (2), adding water, plant essential oil and emulsifier into the reaction bottle, stirring and mixing, adding antibacterial cyclodextrin microcapsules, stirring for inclusion, filtering, washing with distilled water, and drying to obtain antibacterial essential oil microcapsules.

2. The method for preparing the antibacterial essential oil microcapsules according to claim 1, characterized in that: In the step (1), the mass ratio of acryloyl-β-cyclodextrin, diquaternary ammonium diacrylate monomer, ammonium persulfate and sodium bisulfite is 100:(5-20):(0.04-0.18):(0.016-0.068).

3. The method for preparing the antibacterial essential oil microcapsules according to claim 1, characterized in that: The reaction temperature in step (1) is 50-60°C and the reaction time is 12-18h.

4. The method for preparing the antibacterial essential oil microcapsules according to claim 1, characterized in that: In the step (2), the mass ratio of the plant essential oil to the antibacterial cyclodextrin microcapsules is (10-60):

100.

5. The method for preparing the antibacterial essential oil microcapsules according to claim 1, characterized in that: The temperature during the inclusion in step (2) is 40-60° C. and the time is 2-3 hours.

6. The method for preparing the antibacterial essential oil microcapsules according to claim 1, characterized in that: The plant essential oils include rose essential oil, jasmine essential oil and orange peel essential oil.

7. The method for preparing the antibacterial essential oil microcapsules according to claim 1, characterized in that: The preparation method of the diquaternary ammonium salt diacrylate monomer comprises: step S1, adding N,N-dimethylformamide solvent, ethylenediaminetetraacetic acid dianhydride, and N,N-dimethylethylenediamine into a reaction bottle, introducing nitrogen, reacting at 60-75° C. for 12-18 hours, distilling the solution under reduced pressure, and recrystallizing the product with ethanol to obtain intermediate 1; Step S2, add isopropanol, intermediate 1, and hydrochloric acid solution into a reaction bottle, add glycidyl methacrylate after stirring, introduce nitrogen, react at 65-75° C. for 2-4 hours, rotary evaporate the solution, wash the product with petroleum ether, and recrystallize with ethanol to obtain a diquaternary ammonium diacrylate monomer.

8. The method for preparing antibacterial essential oil microcapsules according to claim 1, characterized in that: In the step S1, the molar ratio of ethylenediaminetetraacetic dianhydride to N,N-dimethylethylenediamine is 1:(2.1-2.2).

9. The method for preparing antibacterial essential oil microcapsules according to claim 1, characterized in that: The molar ratio of the intermediate 1 to glycidyl methacrylate is 1:(2.2-2.5).

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