Net-shaped double-shell essence microcapsule and preparation method thereof

Abstract

The invention relates to the technical field of microcapsules, and particularly discloses a reticular double-shell essence microcapsule and a preparation method thereof.The microcapsule comprises a core material, an inner shell and an outer shell from inside to outside, the core material is essence, the inner shell is made of a polyurethane material, and the outer shell is made of a polyurea material. Compared with single / double-shell essence microcapsules such as polyurea, polyurethane and melamine resin, the reticular double-shell essence microcapsule disclosed by the invention has good thermal stability and mechanical strength, good sealing property and fragrance retention performance, does not contain formaldehyde, and can be widely applied to the fields of textiles, daily chemicals, coatings, leather and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of microcapsules, and in particular relates to a mesh double-shell flavor microcapsule and a preparation method thereof. Background Art

[0002] Fragrances are widely used in various fields such as textiles, daily chemicals, wall coverings, leather odor masking, and food and tobacco. Traditional flavors are characterized by high volatility and short action time, and are easily affected by light, oxygen, temperature, acid and alkali, resulting in serious loss of fragrance. Fragrance microcapsules are mainly made of natural or synthetic polymer materials as shell materials to coat the fragrances, which can effectively isolate the external environment, improve the stability and sustained release of the fragrance, and achieve a long-lasting fragrance effect. At present, the fragrance microcapsules sold on the market have poor thermal stability and insufficient mechanical strength. The shell material is easily affected by the external environment and breaks, resulting in poor fragrance persistence. Most of the fragrance microcapsules with good fragrance retention performance contain formaldehyde, which is harmful to the human body and the environment. Therefore, it is of great significance to develop a fragrance microcapsule with excellent thermal stability and mechanical strength, good fragrance retention performance and no formaldehyde. Summary of the invention

[0003] The invention provides a mesh double-shell flavor microcapsule and a preparation method thereof. The microcapsule has good thermal stability and mechanical strength, good sealing and fragrance retention properties, and does not contain formaldehyde.

[0004] The technical solution of the present invention is to provide a reticulated double-shell flavor microcapsule, which includes a core material, an inner shell layer and an outer shell layer from the inside to the outside, wherein the core material is flavor, the inner shell layer is a polyurethane material, the outer shell layer is a polyurea material, and the mass ratio of the inner shell layer to the outer shell layer is 2 to 8:1 to 6.

[0005] In some embodiments, the flavor includes but is not limited to one or more of peony flavor, lavender flavor, mint flavor, rose flavor, wormwood flavor, sandalwood flavor, jasmine flavor, apple flavor and cherry blossom flavor.

[0006] In some embodiments, the polyurethane material is prepared by using triol, polyether polyol and diisocyanate; the polyurea material is prepared by using triol, polyamine and diisocyanate.

[0007] In some embodiments, at least one of the following conditions is met: The triol is one or more of glycerol, triethanolamine and trimethylolpropane; The polyether polyol is one or more of polyethylene glycol, polypropylene glycol and polytetramethylene glycol, and the molecular weight of the polyether polyol is 500 to 2000; The diisocyanate is one or more of isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and hexamethylene diisocyanate; The polyamine is one or more of diethylenetriamine, ethylenediamine, p-phenylenediamine, isophoronediamine, dicyclohexylmethanediamine, tetramethylenediamine, hexamethylenediamine and triethylenetetramine.

[0008] In some embodiments, the mass ratio of the flavor, diisocyanate, polyether polyol, polyamine and triol is 40-80:5-20:2-9:2-5:4-8.

[0009] The present invention also relates to a method for preparing the microcapsules, which is characterized by comprising the following steps: S1, mixing essence, diisocyanate and polyether polyol to prepare an oil phase; S2, mixing the anionic emulsifier and the oil phase uniformly for emulsification to obtain an O / W type oil-in-water emulsion; S3, adding polyamine and triol into the oil-in-water emulsion for curing reaction, keeping warm for a period of time and then cooling to room temperature, spray drying to obtain the net-shaped double-shell flavor microcapsules.

[0010] In some embodiments, the mass ratio of the anionic emulsifier to the oil phase is (2-6):1; the anionic emulsifier includes but is not limited to one or more of styrene-maleic anhydride copolymer, sodium dodecylbenzene sulfonate and sodium dodecyl sulfate, and its solid content is 2-10%.

[0011] In some embodiments, during emulsification in S2, the emulsification temperature is 25-40° C., the emulsification rate is 1000-3000 rpm, and the emulsification time is 5-20 min.

[0012] In some embodiments, the insulation temperature / time is 40-50°C / 1-3h+70-80°C / 1-3h.

[0013] The present invention has the following beneficial effects: During the preparation process of the present invention, diisocyanate diffuses to the shell surface and first reacts with polyamine and triol to form a network polyurea structure on the shell surface. At the same time, polyether polyol and triol inside the core material further react with diisocyanate to form components of a network polyurethane structure inside the shell surface. When the reaction is completed, a network double-shell polyurea / polyurethane shell with a dense cross-linked structure is finally formed. Compared with single / double-layer flavor microcapsules such as polyurea, polyurethane and melamine resin, the network double-shell flavor microcapsule has good thermal stability and mechanical strength, good sealing and fragrance retention performance, does not contain formaldehyde, and can be widely used in the fields of textiles, daily chemicals, coatings, leather, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a SEM scanning electron microscope image of the reticulated double-shell flavor microcapsule prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0015] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0016] Example 1 60 parts of sandalwood essence, 10 parts of toluene diisocyanate and 4.5 parts of polyethylene glycol (PEG2000) were mixed evenly to prepare the oil phase. 180 parts of sodium dodecylbenzene sulfonate (5%) were mixed evenly with the oil phase, and emulsified at 30°C and 3000rpm for 10 minutes to obtain an O / W type oil-in-water emulsion. 2.5 parts of ethylenediamine and 4.5 parts of trimethylolpropane were added to the oil-in-water emulsion for curing reaction. The insulation temperature / time was 40°C / 2h+70°C / 2h. After the insulation was completed, it was cooled to room temperature and spray-dried to obtain a reticulated double-shell peony essence microcapsule.

[0017] Example 2 60 parts of sandalwood essence, 20 parts of toluene diisocyanate and 9 parts of polyethylene glycol (PEG2000) were mixed evenly to prepare the oil phase. 180 parts of sodium dodecylbenzene sulfonate (5%) were mixed evenly with the oil phase, and emulsified at 30°C and 3000rpm for 10 minutes to obtain an O / W type oil-in-water emulsion. 5 parts of ethylenediamine and 9 parts of trimethylolpropane were added to the oil-in-water emulsion for curing reaction. The insulation temperature / time was 40°C / 2h+70°C / 2h. After the insulation was completed, it was cooled to room temperature and spray-dried to obtain a reticulated double-shell peony essence microcapsule.

[0018] Example 3 60 parts of peony essence, 10 parts of isophorone diisocyanate and 2.5 parts of polypropylene glycol (PPG2000) were mixed evenly to prepare the oil phase. 180 parts of styrene-maleic anhydride copolymer (5%) and the oil phase were mixed evenly and emulsified at 30°C and 1000rpm for 15 minutes to obtain an O / W type oil-in-water emulsion. 2.5 parts of diethylenetriamine and 4.5 parts of triethanolamine were added to the oil-in-water emulsion for curing reaction. The insulation temperature / time was 40°C / 2h+70°C / 2h. After the insulation was completed, it was cooled to room temperature and spray-dried to obtain a reticulated double-shell peony essence microcapsule.

[0019] Example 4 60 parts of peony essence, 10 parts of isophorone diisocyanate and 2.5 parts of polypropylene glycol (PPG2000) were mixed evenly to prepare the oil phase. 180 parts of styrene-maleic anhydride copolymer (5%) and the oil phase were mixed evenly and emulsified at 30°C and 3000rpm for 10 minutes to obtain an O / W type oil-in-water emulsion. 2.5 parts of diethylenetriamine and 4.5 parts of triethanolamine were added to the oil-in-water emulsion for curing reaction. The insulation temperature / time was 40°C / 2h+70°C / 2h. After the insulation was completed, it was cooled to room temperature and spray-dried to obtain a reticulated double-shell peony essence microcapsule.

[0020] Example 5 60 parts of peony essence, 10 parts of isophorone diisocyanate and 2.5 parts of polypropylene glycol (PPG2000) were mixed evenly to prepare the oil phase. 180 parts of styrene-maleic anhydride copolymer (5%) and the oil phase were mixed evenly and emulsified at 30°C and 3000rpm for 10 minutes to obtain an O / W type oil-in-water emulsion. 2.5 parts of diethylenetriamine and 6.5 parts of triethanolamine were added to the oil-in-water emulsion for curing reaction. The insulation temperature / time was 40°C / 2h+70°C / 3h. After the insulation was completed, it was cooled to room temperature and spray-dried to obtain a reticulated double-shell peony essence microcapsule.

[0021] Example 6 90 parts of peony essence, 10 parts of isophorone diisocyanate and 2.5 parts of polypropylene glycol (PPG2000) were mixed evenly to prepare the oil phase. 180 parts of styrene-maleic anhydride copolymer (10%) and the oil phase were mixed evenly and emulsified at 30°C and 3000rpm for 10 minutes to obtain an O / W type oil-in-water emulsion. 2.5 parts of diethylenetriamine and 6.5 parts of triethanolamine were added to the oil-in-water emulsion for curing reaction. The insulation temperature / time was 40°C / 2h+70°C / 2h. After the insulation was completed, it was cooled to room temperature and spray-dried to obtain a reticulated double-shell peony essence microcapsule.

[0022] Example 7 60 parts of peony essence, 10 parts of isophorone diisocyanate and 2.5 parts of polypropylene glycol (PPG500) were mixed evenly to prepare the oil phase. 180 parts of styrene-maleic anhydride copolymer (5%) and the oil phase were mixed evenly and emulsified at 30°C and 3000rpm for 10 minutes to obtain an O / W type oil-in-water emulsion. 2.5 parts of diethylenetriamine and 6.5 parts of triethanolamine were added to the oil-in-water emulsion for curing reaction. The insulation temperature / time was 40°C / 2h+70°C / 2h. After the insulation was completed, it was cooled to room temperature and spray-dried to obtain a reticulated double-shell peony essence microcapsule.

[0023] Comparative Example 1 60 parts of peony essence and 10 parts of isophorone diisocyanate were mixed evenly to prepare the oil phase. 180 parts of styrene-maleic anhydride copolymer (5%) were mixed evenly with the oil phase, and emulsified at 30°C and 3000rpm for 10 minutes to obtain an O / W type oil-in-water emulsion. 2.5 parts of diethylenetriamine and 4.5 parts of triethanolamine were added to the oil-in-water emulsion for curing reaction, and the insulation temperature / time was 40°C / 2h+70°C / 2h. After the insulation was completed, it was cooled to room temperature and spray-dried to obtain a reticular single-shell polyurea peony essence microcapsule.

[0024] Comparative Example 2 60 parts of peony essence, 10 parts of isophorone diisocyanate and 2.5 parts of polypropylene glycol (PPG2000) were mixed evenly to prepare the oil phase. 180 parts of styrene-maleic anhydride copolymer (5%) and the oil phase were mixed evenly and emulsified at 30°C and 3000rpm for 10 minutes to obtain an O / W type oil-in-water emulsion. 5 parts of triethanolamine were added to the oil-in-water emulsion for curing reaction. The insulation temperature / time was 40°C / 2h+70°C / 2h. After the insulation was completed, it was cooled to room temperature and spray-dried to obtain a reticular single-shell polyurethane peony essence microcapsule.

[0025] Comparative Example 3 60 parts of peony essence, 10 parts of isophorone diisocyanate and 2.5 parts of polypropylene glycol (PPG2000) were mixed evenly to prepare the oil phase. 180 parts of styrene-maleic anhydride copolymer (5%) and the oil phase were mixed evenly and emulsified at 30°C and 3000rpm for 10 minutes to obtain an O / W type oil-in-water emulsion. 5 parts of diethylenetriamine were added to the oil-in-water emulsion for curing reaction. The insulation temperature / time was 40°C / 2h+70°C / 2h. After the insulation was completed, it was cooled to room temperature and spray-dried to obtain linear double-shell peony essence microcapsules.

[0026] Comparative Example 4 60 parts of peony essence, 10 parts of isophorone diisocyanate and 2.5 parts of propylene glycol were mixed evenly to prepare the oil phase. 180 parts of styrene-maleic anhydride copolymer (5%) and the oil phase were mixed evenly, and emulsified at 30°C and 3000rpm for 10 minutes to obtain an O / W type water-in-oil emulsion. 2.5 parts of diethylenetriamine and 4.5 parts of triethanolamine were added to the water-in-oil emulsion for curing reaction, and the insulation temperature / time was 40°C / 2h+70°C / 2h. After the insulation was completed, it was cooled to room temperature and spray-dried to obtain a network composite peony essence microcapsule.

[0027] Comparative Example 5 60 parts of peony essence, 10 parts of isophorone diisocyanate and 2.5 parts of polypropylene glycol (PPG2000) were mixed evenly to prepare the oil phase. 180 parts of styrene-maleic anhydride copolymer (5%) and the oil phase were mixed evenly and emulsified at 30°C and 3000rpm for 10 minutes to obtain an O / W type oil-in-water emulsion. 2.5 parts of diethylenetriamine and 4.5 parts of triethanolamine were added to the oil-in-water emulsion for curing reaction. The insulation temperature / time was 40°C / 4h. After the insulation was completed, it was cooled to room temperature and spray-dried to obtain a reticulated double-shell peony essence microcapsule.

[0028] The comparison results of the indicators of the fragrance microcapsules prepared in the above embodiments and comparative examples and the commercially available fragrance microcapsules are shown in Table 1, and the comparison results of the thermal stability and fragrance retention performance are shown in Table 2.

[0029] Table 1 Comparison results of indicators of the examples, comparative examples and commercially available flavor microcapsules

[0030] Note: (1) The aroma and appearance are determined by olfaction and visual inspection respectively; (2) The particle size is determined by the method specified in GB / T19077-2016; (3) The compressive strength is determined by the method specified in T / CTES1005-2017; (4) The formaldehyde content is determined by the method specified in HJ601-2011.

[0031] From the comparison results of Examples 1 and 2, it can be seen that when the amount of shell material increases, the particle size and compressive strength of the reticulated double-shell sandalwood essence microcapsule are significantly increased; the product indicators of Example 1 are basically equivalent to those of commercially available sandalwood essence microcapsules, and do not contain formaldehyde; from the comparison results of Examples 3 and 4, it can be seen that the particle size of the reticulated double-shell peony essence microcapsule decreases with the increase of emulsification rate, and the compressive strength increases accordingly; from the comparison results of Examples 4 and 5, it can be seen that appropriately increasing the amount of triol and extending the insulation time can promote the crosslinking density of the reticulated shell material, and the shell material monomer is more completely cured, resulting in an increase in compressive strength; from the comparison results of Examples 4 and 6, it can be seen that the fragrance is used. The increase in the amount will lead to an increase in the particle size and a decrease in the compressive strength; from the comparison results of Examples 4 and 7, it can be seen that when the molecular weight of the polyether polyol is low, the particle size and the pressure resistance of the flavor microcapsule will be affected; from the comparison results of Example 4 and Comparative Examples 1 to 3, it can be seen that the compressive strength of the reticulated double-shell peony flavor microcapsule is better than that of the reticulated single-shell and linear double-shell peony flavor microcapsules; from the comparison results of Example 4 and Comparative Example 4, it can be seen that the reaction rate of small molecule alcohols is fast, which will affect the formation of the double-shell flavor microcapsules, resulting in lower pressure resistance; from the comparison results of Example 4 and Comparative Example 5, it can be seen that low temperature will affect the cross-linking density and curing degree of the shell, thereby affecting the compressive strength.

[0032] Table 2 Comparison of thermal stability and fragrance retention performance of the embodiments, comparative examples and commercially available fragrance microcapsules

[0033] Note: (1) Thermal stability evaluation method: 1g of reticulated double-shelled flavor microcapsules were placed in a 120℃ oven, and the mass loss rate (%) at 30min, 60min, 90min and 120min was recorded. The smaller the value, the better the thermal stability. (2) Fragrance retention performance evaluation method: 1g of reticulated double-shelled flavor microcapsules were placed in a natural environment, and the fragrance scores at the initial stage, 30 days, 90 days and 180 days were evaluated (0 represents no fragrance, 2 represents a faint fragrance, 4 represents a continuous fragrance, 6 represents a fragrance of appropriate intensity, 8 represents a slightly strong fragrance, and 10 represents a very strong fragrance).

[0034] From the comparison results of Example 1 and the commercially available sandalwood essence microcapsules, it can be seen that the thermal stability and fragrance retention performance are basically equivalent; from the comparison results of Examples 1 and 2, it can be seen that when the amount of shell material increases, the shell layer becomes thicker, the thermal stability becomes better, the fragrance retention is more lasting, but the initial fragrance becomes lighter; from the comparison results of Examples 3 and 4, it can be seen that the larger the particle size of the reticulated double-shell peony essence microcapsules, the worse the thermal stability and fragrance retention performance, but the stronger the initial fragrance; from the comparison results of Examples 4 and 5, it can be seen that the appropriate increase in the amount of triol and the delay Long heat preservation time can improve thermal stability and has little effect on fragrance retention performance; from the comparison results of Examples 4 and 6, it can be seen that the fragrance retention effect is better with increasing the amount of fragrance used; from the comparison results of Example 4 and Comparative Examples 1 to 4, it can be seen that the thermal stability and fragrance retention performance of the reticulated double-shell peony fragrance microcapsules are better than those of the reticulated single-shell, reticulated composite shell and linear double-shell peony fragrance microcapsules; from the comparison results of Example 4 and Comparative Example 5, it can be seen that the thermal stability and fragrance retention effect of the fragrance microcapsules prepared by low-temperature heat preservation are not good.

[0035] The above embodiments describe the preferred implementation of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A mesh double-shell flavor microcapsule, characterized in that: It comprises a core material, an inner shell layer and an outer shell layer from inside to outside, wherein the core material is essence, the inner shell layer is a polyurethane material, the outer shell layer is a polyurea material, and the mass ratio of the inner shell layer to the outer shell layer is 2-8:1-6.

2. The microcapsule according to claim 1, characterized in that: The flavor includes but is not limited to one or more of peony flavor, lavender flavor, mint flavor, rose flavor, wormwood flavor, sandalwood flavor, jasmine flavor, apple flavor and cherry flavor.

3. The microcapsule according to claim 1, characterized in that: The polyurethane material is prepared by using triol, polyether polyol and diisocyanate; the polyurea material is prepared by using triol, polyamine and diisocyanate.

4. The microcapsule according to claim 3, characterized in that It meets at least one of the following conditions: The triol is one or more of glycerol, triethanolamine and trimethylolpropane; The polyether polyol is one or more of polyethylene glycol, polypropylene glycol and polytetramethylene glycol, and the molecular weight of the polyether polyol is 500 to 2000; The diisocyanate is one or more of isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and hexamethylene diisocyanate; The polyamine is one or more of diethylenetriamine, ethylenediamine, p-phenylenediamine, isophoronediamine, dicyclohexylmethanediamine, tetramethylenediamine, hexamethylenediamine and triethylenetetramine.

5. The microcapsule according to claim 1, characterized in that: The mass ratio of the essence, diisocyanate, polyether polyol, polyamine and triol is 40-80:5-20:2-9:2-5:4-8.

6. The method for preparing microcapsules according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, mixing essence, diisocyanate and polyether polyol to prepare an oil phase; S2, mixing the anionic emulsifier and the oil phase uniformly for emulsification to obtain an O / W type oil-in-water emulsion; S3, adding polyamine and triol into the oil-in-water emulsion for curing reaction, keeping warm for a period of time and then cooling to room temperature, spray drying to obtain the net-shaped double-shell flavor microcapsules.

7. The preparation method according to claim 6, characterized in that: The mass ratio of the anionic emulsifier to the oil phase is (2-6):1; the anionic emulsifier includes but is not limited to one or more of styrene-maleic anhydride copolymer, sodium dodecylbenzene sulfonate and sodium dodecyl sulfate, and its solid content is 2-10%.

8. The preparation method according to claim 6, characterized in that: During emulsification in S2, the emulsification temperature is 25-40°C, the emulsification rate is 1000-3000rpm, and the emulsification time is 5-20min.

9. The preparation method according to claim 6, characterized in that: The insulation temperature / time is 40-50℃ / 1-3h+70-80℃ / 1-3h.

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