Amine microcapsule as well as preparation method and application thereof

Abstract

The invention relates to the technical field of microencapsulation, in particular to an amine microcapsule as well as a preparation method and application thereof. The amine microcapsule comprises a core part and a capsule shell coating the core part, the core part comprises a macromolecular amine compound; the molecular weight of the macromolecular amine compound is 2500 g / mol to 3500 g / mol, and the viscosity of the macromolecular amine compound is 350 mPa.s to 450 mPa.s; the capsule shell is prepared from polyurea; the preparation raw materials of the polyurea comprise the macromolecular amine compound, an isocyanate compound and an aromatic fatty amine compound; the molecular weight of the aromatic fatty amine compound is 100 g / mol to 200 g / mol, and the viscosity of the aromatic fatty amine compound is 5 mPa.s to 10 mPa.s. The amine microcapsule disclosed by the invention is high in encapsulation efficiency, strong in stability and good in heat resistance.

Description

Technical Field

[0001] This application relates to the technical field of microencapsulation, and particularly relates to an amine microcapsule, a preparation method thereof, and an application thereof. Background Art

[0002] Microcapsules are a type of microcapsule structure with diameters in the micrometer or even nanometer range, usually including a core and a shell encapsulating the core. The encapsulation of the shell can protect the core material from external factors. Amine microcapsules are a type of microcapsules with an amine compound as the core component. Such microcapsules can be used to prepare condition-responsive curing agents and have important applications in resin curing, self-healing, etc.

[0003] Currently, the methods for preparing microcapsules (microencapsulation) mainly include the emulsion method, the microfluidic method, and the interfacial polymerization method. Through the above methods, some common amine compounds such as ethylenediamine condensates and low molecular weight polyetheramines can be prepared into corresponding microcapsules. However, the amine compounds encapsulated by the above methods are usually selected from organic polyamines with relatively small molecular weights. Due to their relatively small molecular weights and low viscosities, these compounds are conducive to the formation of microdroplets, and then can be made into microcapsules through the above microencapsulation methods. However, for amine compounds with high molecular weights and high viscosities, the existing microencapsulation methods cannot achieve encapsulation.

[0004] With the continuous progress of materials science, the demand for high-temperature resistant materials has gradually expanded, thus giving rise to the demand for high-temperature resistant amine microcapsules. In the absence of additives, the larger the molecular weight and the higher the viscosity of the amine compound, the better the high-temperature resistance effect. Therefore, how to prepare high molecular weight amine compounds into microcapsules is an urgent problem to be solved. Summary of the Invention

[0005] Based on this, one or more embodiments of this application provide an amine microcapsule, a preparation method thereof, and an application thereof. The technical solution of this application realizes the encapsulation of high molecular weight amine compounds. This amine microcapsule has high stability and a simple preparation method.

[0006] The technical solution of this application includes the following content:

[0007] An embodiment of this application provides an amine microcapsule, including a core and a shell encapsulating the core;

[0008] The composition of the core includes a high molecular weight amine compound; the molecular weight of the high molecular weight amine compound is 2500 g / mol to 3500 g / mol, and the viscosity is 350 mPa·s to 450 mPa·s;

[0009] The composition of the capsule shell includes polyurea; the raw materials for preparing the polyurea include the high molecular amine compound, the isocyanate compound, and the aromatic aliphatic amine compound; the molecular weight of the aromatic aliphatic amine compound is 100 g / mol to 200 g / mol, and the viscosity is 5 mPa·s to 10 mPa·s.

[0010] In the amine microcapsules of the present application, the composition of the core includes a high molecular weight and high viscosity high molecular amine compound, and the composition raw materials of the capsule shell include a low molecular weight and low viscosity aromatic aliphatic amine compound. By using the above-mentioned aromatic aliphatic amine and high molecular amine compound in combination, the microencapsulation of the high molecular amine compound can be achieved, and the amine microcapsules have a high encapsulation rate and good stability.

[0011] In this embodiment, since the aromatic aliphatic amine compound has a low molecular weight and viscosity, it can reduce the viscosity of the high molecular amine compound to promote the formation of microdroplets. At the same time, the aromatic aliphatic amine compound has high activity and a small molecular weight, and can quickly diffuse from the microdroplets to quickly form a shell with the shell-forming monomer in the reaction solution. Because of its small molecular weight, it is also easier to diffuse through the formed polyurea capsule wall during the microencapsulation process, making the reaction conditions for preparing microcapsules milder. And because the density of the aromatic aliphatic amine compound is relatively high, it also plays a role in regulating the density of the microdroplets, avoiding the floating and agglomeration phenomena caused by the density mismatch between the microdroplets and the reaction solution. In addition, the aromatic aliphatic amine and the high molecular amine compound have good mutual solubility, which can effectively prevent phase separation during the microencapsulation process, thereby inhibiting the rapid diffusion of the high molecular amine compound and being beneficial to improving the encapsulation rate. The embodiment of the present application also provides a preparation method for the above-mentioned amine microcapsules, including the following steps:

[0012] Mix the aromatic aliphatic amine compound and the high molecular amine compound to obtain a homogeneous mixture;

[0013] Dissolve the isocyanate compound, the surfactant, and the catalyst in a solvent to obtain a reaction solution;

[0014] Prepare the homogeneous mixture into microdroplets, and receive the microdroplets with the reaction solution to obtain primary microcapsules;

[0015] Stir the initial microcapsules at a first temperature for a first time to obtain amine microcapsules; the amine microcapsules include a core and a shell covering the core; the composition of the core includes a part of the high molecular weight amine compound; the molecular weight of the high molecular weight amine compound is 2500 g / mol to 3500 g / mol, and the viscosity is 350 mPa·s to 450 mPa·s; the composition of the shell includes polyurea; the raw materials for preparing the polyurea include a part of the high molecular weight amine compound, the isocyanate compound, and the aromatic aliphatic amine compound; the molecular weight of the aromatic aliphatic amine compound is 100 g / mol to 200 g / mol, and the viscosity is 5 mPa·s to 10 mPa·s;

[0016] Among them, the first temperature is 40°C to 70°C, the rotation speed of the stirring is 80 rpm to 120 rpm, and the first time is 3 h to 5 h.

[0017] In the preparation method of the present application, the aromatic aliphatic amine compound and the high molecular weight amine compound are first mixed to obtain a homogeneous mixture. The aromatic aliphatic amine compound and the high molecular weight amine compound have the above characteristics and thus have good solubility, and meet the conditions for forming microdroplets, so microdroplets can be conveniently obtained. After receiving the microdroplets with a solution containing an isocyanate compound, a surfactant, and a catalyst as the reaction solution, primary microcapsules can be formed by interfacial polymerization. Further, by heating, stirring, washing, and drying under appropriate conditions, amine microcapsules can be obtained.

[0018] In this example, after the microdroplets are received into the reaction solution, the aromatic aliphatic amine can quickly diffuse from the microdroplets and form a shell with the shell-forming monomer (isocyanate compound). Under the promotion of the surfactant and the catalyst, a polyurea capsule wall is quickly formed, and at the same time, the high molecular weight amine compound is wrapped in the core to form primary microcapsules. During the heating and stirring process, the aromatic aliphatic amine diffuses through the already formed polyurea capsule wall to further form a capsule wall to improve the encapsulation strength, and amine microcapsules with a high encapsulation rate and good stability are obtained. The embodiment of the present application also provides an application of the above-mentioned amine microcapsules in the preparation of a curing agent.

[0019] When the amine microcapsules of the present application are used as a curing agent or for preparing a curing agent, they have the advantages of good stability and high temperature resistance, and will not volatilize and decompose due to too high temperature. Therefore, the matrix material is allowed to be pretreated at a higher temperature, and at the same time, it also has good stability and will not break and fail under non-trigger conditions. Description of the Drawings

[0020] To more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is the structure of the amine microcapsules of Example 1 of the present application; Figure 1 where a is a physical photo; Figure 1 where b, c, and d are microstructures, and the scales are 200 μm, 100 μm, and 10 μm respectively.

[0022] Figure 2 It is the thermogravimetric curve of the high molecular amine compound (T3000) used in Example 1 of the present application at 120 °C and 140 °C.

[0023] Figure 3 It is the thermogravimetric curve of the high molecular amine compound (T3000), the auxiliary shell-forming agent, the amine microcapsules prepared in Example 1, and their outer shells of the present application at 1 - 500 °C.

[0024] Figure 4 It is the microstructure of the amine microcapsules of Example 2 of the present application; the scale is 100 μm.

[0025] Figure 5 It is the microstructure of the amine microcapsules of Example 3 of the present application; the scale is 500 μm.

[0026] Figure 6 It is the microstructure of the amine microcapsules of Example 4 of the present application; Figure 6 where the scales of a and b are 400 μm and 40 μm respectively.

[0027] Figure 7 It is the microstructure of the amine microcapsules of Example 5 of the present application; Figure 7 where the scales of a and b are 300 μm and 40 μm respectively.

[0028] Figure 8 It is the microstructure of the amine microcapsules of Example 6 of the present application; Figure 8 where the scales of a and b are 1 mm and 50 μm respectively.

[0029] Figure 9 It is the microstructure of the amine microcapsules of Example 7 of the present application; Figure 9 where the scales of a and b are 300 μm and 20 μm respectively.

[0030] Figure 10Microstructure of the amine microcapsules of Example 8 of the present application; Figure 10 The scales of a and b in it are 200 μm and 40 μm respectively.

[0031] Figure 11 Microstructure diagram of the amine microcapsules of Comparative Example 1 of the present application; Figure 11 The scale in it is 200 μm.

[0032] Figure 12 Microstructure diagram of the amine microcapsules of Comparative Example 2 of the present application; Figure 12 The scale in it is 1 mm.

[0033] Figure 13 Microstructure diagram of the amine microcapsules of Comparative Example 3 of the present application; Figure 13 The scale in it is 200 μm. Detailed implementation manners

[0034] The present application will be further described below in combination with the implementation manners and examples. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application. In addition, it should be understood that after reading the content taught in the present application, those skilled in the art can make various changes or modifications to the present application, and these equivalent forms also fall within the protection scope of the appended claims of the present application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0036] Terms

[0037] Unless otherwise stated or there is a contradiction, the terms or phrases used herein have the following meanings:

[0038] The term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of the related listed items. The said any and all combinations include combinations of any two related listed items, any more related listed items, or all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", "and / or", it should be understood that in this application, this technical solution undoubtedly includes the technical solution connected by "logical AND", and also undoubtedly includes the technical solution connected by "logical OR". For example, "A and / or B" includes three parallel solutions: A, B, and A + B.

[0039] In this application, "further" is used for descriptive purposes, indicating differences in content, but should not be construed as a limitation on the scope of protection of this application.

[0040] In this application, "first", "second", "third", "fourth", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or quantity, nor can they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumerative description and should be understood not to constitute a closed limitation on quantity.

[0041] In this application, among the technically characterized features described in an open-ended manner, there are included closed technical solutions composed of the listed features, as well as open technical solutions containing the listed features.

[0042] In this application, regarding numerical intervals (i.e., numerical ranges), unless otherwise specified, the selectable numerical values are considered continuous within the above numerical intervals and include the two numerical endpoints (i.e., the minimum value and the maximum value) of this numerical range, as well as each numerical value between these two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to integers within the numerical interval, it includes the two endpoint integers of this numerical range, as well as each integer between the two endpoints. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0043] For the temperature parameters in this application, unless otherwise specified, both constant temperature treatment is allowed and fluctuations within a certain temperature range are allowed. It should be understood that the so-called constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within ranges such as ±5°C, ±4°C, ±3°C, ±2°C, ±1°C are allowed.

[0044] In this application, the weight can be mass units well-known in the chemical engineering field such as μg, mg, g, kg, etc.

[0045] In this application, unless otherwise specified, when it comes to dimensions, particle sizes, diameters, it generally refers to the average value.

[0046] The embodiments of this application provide an amine microcapsule, including a core and a capsule shell covering the core;

[0047] The composition of the core includes a high molecular weight amine compound; the molecular weight of the high molecular weight amine compound is 2500 g / mol to 3500 g / mol, and the viscosity is 350 mPa·s to 450 mPa·s;

[0048] The composition of the capsule shell includes polyurea; the raw materials for preparing the polyurea include the high molecular amine compound, the isocyanate compound, and the aromatic aliphatic amine compound; the molecular weight of the aromatic aliphatic amine compound is 100 g / mol to 200 g / mol, and the viscosity is 5 mPa·s to 10 mPa·s.

[0049] In the amine microcapsules of the present application, the composition of the core includes a high molecular weight and high viscosity high molecular amine compound, and the raw materials for the composition of the capsule shell include a low molecular weight and low viscosity aromatic aliphatic amine compound. By using the above-mentioned aromatic aliphatic amine and high molecular amine compound in combination, the microencapsulation of the high molecular amine compound can be achieved, and the amine microcapsules have a high encapsulation rate and good stability.

[0050] In this example, since the aromatic aliphatic amine compound has a low molecular weight and viscosity, the viscosity of the high molecular amine compound can be reduced to promote the formation of microdroplets. At the same time, the aromatic aliphatic amine compound has a high activity and a small molecular weight, and can quickly diffuse from the microdroplets to quickly form a shell with the shell-forming monomer in the reaction solution. Because of its small molecular weight, it is also easier to diffuse through the formed polyurea capsule wall during the microencapsulation process, making the reaction conditions for preparing microcapsules milder. And because the density of the aromatic aliphatic amine compound is relatively high, it also plays a role in adjusting the density of the microdroplets, avoiding the floating and agglomeration phenomena caused by the density mismatch between the microdroplets and the reaction solution. In addition, the aromatic aliphatic amine and the high molecular amine compound have good mutual solubility, which can effectively prevent phase separation during the microencapsulation process, thereby inhibiting the rapid diffusion of the high molecular amine compound and being beneficial to improving the encapsulation rate.

[0051] In some embodiments, the amine microcapsules satisfy at least one of the following conditions:

[0052] (1) The ratio of the thickness of the capsule shell to the particle size of the amine microcapsules is 1 to 2:100;

[0053] (2) The particle size of the amine microcapsules is 1 μm to 200 μm.

[0054] In some embodiments, the composition of the core includes at least 90% mass concentration of the high molecular amine compound.

[0055] In some embodiments, the high molecular amine compounds in the core and the capsule shell independently include polyetheramine compounds.

[0056] In some embodiments, the isocyanate compound includes dicyclohexylmethane diisocyanate.

[0057] In some embodiments, the aromatic aliphatic amine compound includes m-xylylenediamine. When m-xylylenediamine is used in combination with the above-mentioned high molecular amine compound, it can better coordinate the viscosity, promote shell formation and play a role in regulating density. Moreover, m-xylylenediamine has better solubility and activity, effectively avoiding agglomeration, inhibiting phase separation, inhibiting the diffusion of core components and promoting the rapid formation of the capsule shell, which is beneficial to improving the encapsulation efficiency.

[0058] In some embodiments, the high molecular amine compound is selected from the high molecular amine with the trade number JEFFAMINE @ T3000 (hereinafter referred to as T3000). T3000 is an organic polyamine with a molecular weight of about 3000. Its molecular structure contains a large number of propoxy chains and three primary amine groups. It is an organic polyamine curing agent with a relatively large molecular weight, high viscosity and excellent thermal stability. Due to the large number of propoxy chains in its molecular structure, the cured epoxy product of T3000 has good flexibility. By microencapsulating T3000, the application range of T3000 can be expanded, and the development of microcapsule-type functional materials with higher processing or service temperatures can be greatly promoted.

[0059] The embodiment of the present application also provides a preparation method of the above-mentioned amine microcapsules, including the following steps:

[0060] Mix the aromatic aliphatic amine compound and the high molecular amine compound to obtain a homogeneous mixture;

[0061] Dissolve the isocyanate compound, surfactant and catalyst in a solvent to obtain a reaction solution;

[0062] Prepare the homogeneous mixture into microdroplets, and receive the microdroplets with the reaction solution to obtain primary microcapsules;

[0063] Stir the initial microcapsules at a first temperature for a first time to obtain amine microcapsules; the amine microcapsules include a core and a capsule shell covering the core; the composition of the core includes a part of the high molecular amine compound; the molecular weight of the high molecular amine compound is 2500 g / mol to 3500 g / mol, and the viscosity is 350 mPa·s to 450 mPa·s; the composition of the capsule shell includes polyurea; the raw materials for preparing polyurea include a part of the high molecular amine compound, isocyanate compound and aromatic aliphatic amine compound; the molecular weight of the aromatic aliphatic amine compound is 100 g / mol to 200 g / mol, and the viscosity is 5 mPa·s to 10 mPa·s;

[0064] Wherein, the first temperature is 40°C to 70°C, the stirring speed is 80 rpm to 120 rpm, and the first time is 3 h to 5 h.

[0065] In the preparation method of the present application, an aromatic aliphatic amine compound and a high-molecular amine compound are first mixed to obtain a homogeneous mixture. The aromatic aliphatic amine compound and the high-molecular amine compound have good miscibility due to the above characteristics and meet the conditions for the formation of microdroplets, so microdroplets can be conveniently obtained. After receiving the microdroplets with a solution containing an isocyanate compound, a surfactant and a catalyst as the reaction solution, primary microcapsules can be formed through interfacial polymerization. Further, by heating, stirring, washing and drying under appropriate conditions, amine microcapsules can be obtained.

[0066] In this example, after the microdroplets are received into the reaction solution, the aromatic aliphatic amine can rapidly diffuse from the microdroplets and form a shell with the shell-forming monomer (isocyanate compound). Under the promotion of the surfactant and the catalyst, a polyurea capsule wall is rapidly formed, and at the same time, the high-molecular amine compound is wrapped in the core to form primary microcapsules. During the heating and stirring process, the aromatic aliphatic amine diffuses through the formed polyurea capsule wall to further form a capsule wall to improve the encapsulation strength, and amine microcapsules with a high encapsulation rate and good stability are obtained.

[0067] In some embodiments, the particle size of the microdroplets is 1 μm to 200 μm. Optionally, the particle size of the microdroplets can be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 20 μm, 30 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 200 μm, etc.

[0068] In some embodiments, the concentration of the isocyanate compound in the reaction solution is 0.08 to 0.2 g / mL. Optionally, the concentration of the isocyanate compound in the reaction solution can be 0.08 g / mL, 0.1 g / mL, 0.15 g / mL, 0.18 g / mL, 0.2 g / mL, etc.

[0069] In some embodiments, the weight ratio of the high-molecular amine compound to the aromatic aliphatic amine compound is 9:1 to 5:5. Optionally, the weight ratio of the high-molecular amine compound to the aromatic aliphatic amine compound can be 9:1, 9:2, 3:1, 9:4, 9:5, 3:2, 9:7, 9:8, 1:1, 1:2, 1:3, 1:4, 1:5, etc.

[0070] In some embodiments, the weight ratio of the isocyanate compound, surfactant, and catalyst is 4 to 10:1:0.04 to 0.06. Optionally, the weight ratio of the isocyanate compound, surfactant, and catalyst can be 4:1:0.04, 4:1:0.05, 4:1:0.06, 5:1:0.04, 5:1:0.05, 5:1:0.06, 6:1:0.04, 6:1:0.05, 6:1:0.06, 7:1:0.04, 7:1:0.05, 7:1:0.06, 8:1:0.04, 8:1:0.05, 8:1:0.06, 9:1:0.04, 9:1:0.05, 9:1:0.06, 10:1:0.04, 10:1:0.05, 10:1:0.06, etc.

[0071] In some embodiments, the surfactant includes a nonionic polymer surfactant.

[0072] In some embodiments, the catalyst includes triethylenediamine. Triethylenediamine, also known as triethylenediamine, has a high catalytic efficiency for the polymer amine compounds and isocyanate compounds of the present application, can accelerate the formation of polyurea, is beneficial to quickly form a core-shell structure in interfacial polymerization, reduce the diffusion loss of the core components, and improve the encapsulation rate.

[0073] In some embodiments, the solvent is selected from non-polar solvents; optionally, the non-polar solvent includes at least one of hexadecane, liquid paraffin oil, and mineral oil.

[0074] In some embodiments, the method for preparing the homogeneous mixture into microdroplets includes electrospray;

[0075] The voltage of the electrospray is 11 kV to 18 kV, and the spraying rate is 0.1 to 5 mL / h. Optionally, the voltage of the electrospray can be 11 kV, 12 kV, 13 kV, 14 kV, 15 kV, 16 kV, 17 kV, 18 kV, etc., and the spraying rate can be 0.1 mL / h, 0.5 mL / h, 1 mL / h, 1.5 mL / h, 2 mL / h, 3 mL / h, 4 mL / h, 4.5 mL / h, 5 mL / h, etc.

[0076] As used herein, a "homogeneous mixture" refers to a mixture in which the components are uniformly distributed and have consistent properties, and the composition and properties of the components are the same in any part.

[0077] The embodiments of the present application also provide an application of the above amine microcapsules in the preparation of a curing agent.

[0078] When the amine microcapsules of the present application are used as curing agents or for preparing curing agents, they have the advantages of good stability and high temperature resistance, and will not volatilize and decompose due to too high temperature. Therefore, the matrix material is allowed to be pretreated at a higher temperature, and at the same time, it also has good stability and will not break and fail under non-trigger conditions.

[0079] The following are some specific examples.

[0080] For the experimental parameters not specified in the following specific examples, the guidelines given in the present application document shall be preferably referred to. It is also possible to refer to the experimental manuals in the art or other experimental methods known in the art, or the experimental conditions recommended by the manufacturers.

[0081] The raw materials and reagents involved in the following specific examples can be obtained commercially, or can be prepared by those skilled in the art according to known means.

[0082] Raw materials:

[0083] T3000, trade name JEFFAMINE T3000, purchased from Huntsman Corporation, USA;

[0084] XDA, chemical name m-xylylenediamine, purchased from Macklin Chemical Reagent Co., Ltd.;

[0085] Arlacel P135 (trade name), purchased from Croda International Plc, UK;

[0086] HMDI, chemical name 4,4'-dicyclohexylmethane diisocyanate, purchased from Wanhua Chemical Group Co., Ltd., Yantai.

[0087] I. Preparation of amine microcapsules

[0088] Example 1

[0089] This example provides an amine microcapsule of the present application, and its preparation method includes the following steps:

[0090] (1) Mix 20 parts of XDA and 80 parts of T3000 evenly to obtain a homogeneous mixture.

[0091] (2) Add 1 g of Arlacel P135, 8.0 g of HMDI and 0.05 g of catalyst (DABCO, 1,4-diazabicyclo[2.2.2]octane) to 50.0 mL of hexadecane and mix to obtain a reaction solution;

[0092] (3) Load the homogeneous mixture into a syringe and extrude it at a spraying rate of 5 mL / h, and atomize it under a static voltage of 11 kV to form micro-droplets. Receive the micro-droplets with the reaction solution to form primary microcapsules.

[0093] (4) Continuously heat and stir the primary microcapsules in the reaction solution at a heating temperature of 60 °C, a stirring speed of 100 rpm, and a time of 4 h. After stirring, filter, wash the filtrate with pure cyclohexane, and dry it at 35 °C for 1 h to obtain amine microcapsules.

[0094] Example 2

[0095] This example provides an amine microcapsule of the present application, and its preparation method is basically the same as that of Example 1, except that: in step (3), the spraying rate is 1 mL / h and the static voltage is 18 kV. The remaining process is the same as that of Example 1.

[0096] Example 3

[0097] This example provides an amine microcapsule of the present application, and its preparation method is basically the same as that of Example 1, except that: in step (3), the spraying rate is 3 mL / h and the static voltage is 16 kV. The remaining process is the same as that of Example 1.

[0098] Example 4

[0099] This example provides an amine microcapsule of the present application, and its preparation method is basically the same as that of Example 3, except that: in step (1), 90 parts of XDA and 10 parts of T3000 are mixed evenly to obtain a homogeneous mixture. The remaining process is the same as that of Example 3.

[0100] Example 5

[0101] This example provides an amine microcapsule of the present application, and its preparation method is basically the same as that of Example 3, except that:

[0102] In step (1), 50 parts of XDA and 50 parts of T3000 are mixed evenly to obtain a homogeneous mixture. The remaining process is the same as that of Example 3.

[0103] Example 6

[0104] This example provides an amine microcapsule of the present application, and its preparation method is basically the same as that of Example 3, except that: in step (2), decalin is used as the solvent. The remaining process is the same as that of Example 3.

[0105] Example 7

[0106] This example provides an amine microcapsule of the present application, and its preparation method is basically the same as that of Example 2, except that: in step (2), the addition amount of HMDI is 10 g. The remaining process is the same as that of Example 2.

[0107] Example 8

[0108] This embodiment provides an amine microcapsule of the present application. Its preparation method is basically the same as that of Example 2, except that: in step (2), the addition amount of HMDI is 4 g. The remaining processes are the same as those in Example 2.

[0109] Comparative Example 1

[0110] This comparative example provides a preparation method of amine microcapsules, which is basically the same as that of Example 1, except that: diethylenetriamine is used to replace XDA. The remaining processes are the same as those in Example 1.

[0111] Comparative Example 2

[0112] This comparative example provides a preparation method of amine microcapsules, which is basically the same as that of Example 1, except that: the stirring speed is 500 rpm. The remaining processes are the same as those in Example 1.

[0113] Comparative Example 3

[0114] This comparative example provides a preparation method of amine microcapsules, which is basically the same as that of Example 3, except that: the first temperature is 100 °C. The remaining processes are the same as those in Example 1.

[0115] II. Structure Characterization

[0116] The microscopic structure was observed by a scanning electron microscope, including the morphology of the microcapsules and the wall thickness; the composition and thermal stability of the microcapsules were analyzed by a thermogravimetric analyzer.

[0117] (1) Particle Size Analysis

[0118] The amine microcapsules of Example 1 are as Figure 1 shown. The particle size of this microcapsule is about 200 μm, and it has good dispersibility during synthesis. The wall thickness of the capsule is about 3 μm. The amine microcapsules of Example 2 are as Figure 4 shown. The particle size of this microcapsule is about 50 μm. The amine microcapsules of Example 3 are as Figure 5 shown. The particle size of this microcapsule is about 100 μm. It can be seen from Examples 1 to 3 that the particle size of the microcapsules can be regulated by controlling the spraying rate and voltage within a suitable range.

[0119] (2) Core Component Analysis

[0120] Figure 6 shown are the amine microcapsules of Example 4. From Figure 6 it can be seen that when the content of XDA decreases, although the microcapsules can still be prepared, due to the low content of XDA, the wall thickness is limited, and the mismatch between the density of the micro-droplets and the reaction solution also leads to the aggregation of the microcapsules, resulting in a low quality of the collected microcapsules, seriously affecting the microencapsulation process. Figure 7 shown are the amine microcapsules of Example 5. FromFigure 7 It can be seen that when the XDA content rises to 50 wt%, although microcapsules can still be prepared, the main amine curing agent in the core is no longer T3000 (see Table 1).

[0121] Table 1 Core component analysis

[0122]

[0123] (3) Analysis of secondary microspheres

[0124] Figure 8 Shown are the amine microcapsules of Example 6. From Figure 8 it can be seen that when the more polar decalin is used as the reaction solution, adhesion occurs between the microcapsules. The microcapsules are flatter and less plump, and there are also more secondary microspheres on the surface. This is because the increase in solution polarity causes the core liquid to diffuse outward at a faster rate, thereby forming more secondary microspheres.

[0125] Figure 9 Shown are the amine microcapsules of Example 7. From Figure 9 it can be seen that when the HMDI content in the reaction solution increases, the content of secondary microspheres on the surface of the microcapsules decreases. This is because when the amine microdroplets are dropped into the reaction solution, the probability of encountering HMDI becomes larger, resulting in an increase in the shell formation rate, thereby inhibiting the formation of secondary microspheres.

[0126] Figure 10 Shown are the amine microcapsules of Example 8. From Figure 10 it can be seen that when the HMDI content in the reaction solution decreases, the content of secondary microspheres on the surface of the microcapsules increases. This is because when the amine microdroplets are dropped into the reaction solution, the probability of encountering HMDI becomes smaller, resulting in a decrease in the shell formation rate, thereby leading to the formation of secondary microspheres.

[0127] Figure 11 Shown are the amine microcapsules collected in Comparative Example 1 using diethylenetriamine as the shell-forming monomer. These amine microcapsules agglomerate and do not disperse. Although using diethylenetriamine can synthesize the final microcapsules, since the molecular structure of diethylenetriamine only contains a flexible aliphatic chain segment while the molecular structure of XDA contains a rigid benzene ring, the capsule wall of the amine microcapsules prepared using diethylenetriamine is very soft, resulting in the agglomeration and caking of the amine microcapsules after washing and making them impossible to collect.

[0128] Figure 12 Shown is the SEM image of the amine microcapsules prepared at a stirring speed of 500 rpm. As can be seen from the figure, due to the relatively high stirring speed, microcapsules with an unthickened capsule wall are prone to collision under the action of stirring or being torn by the shear force brought by the relatively high stirring speed, resulting in a large number of broken microcapsules in the final product and a low quality of the microcapsule product.

[0129] Figure 13 The amine microcapsules prepared at 100 °C. It can be seen that the amine microcapsules can also be synthesized in Comparative Example 3. However, due to the too high preparation temperature, the amine molecules in the core liquid rapidly diffuse out and participate in the reaction. On the one hand, the polyurea particles on the outer wall of the capsule wall are thick and numerous. On the other hand, the polyurea impurities in the reaction solution increase, resulting in a low encapsulation rate of the prepared amine microcapsules, only about 25%.

[0130] (4)Encapsulation rate

[0131] Figure 3 The thermogravimetric curve of the amine microcapsules of Example 1 is shown. From Figure 3 it can be seen that the content of T3000 in the microcapsules is about 75 wt%.

[0132] All the documents mentioned in this application are cited in this application as references, just as if each document is cited separately as a reference. Unless it conflicts with the application purpose and / or technical solution of this application, the cited documents involved in this application are cited for all contents and all purposes. When this application involves cited documents, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When this application involves cited documents, the examples and preferred methods of the relevant technical features cited can also be used as references and incorporated into this application, but only to the extent that this application can be implemented. It should be understood that when the cited content conflicts with the description in this application, this application shall prevail or be amended adaptively according to the description in this application.

[0133] The technical features of the above-described embodiments and examples can be combined in any suitable manner. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments and examples are described. However, as long as these combinations of technical features do not conflict, they should be considered to be within the scope described in this specification.

[0134] The above-described embodiments only represent several implementation manners of this application, but should not be construed as limiting the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can still be made, and these all belong to the protection scope of this application. In addition, it should be understood that after reading the above teachings of this application, those skilled in the art can make various changes or modifications to this application, and the equivalent forms obtained also fall within the protection scope of this application. It should also be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments based on the technical solutions provided in this application are all within the protection scope of the appended claims of this application. Therefore, the protection scope of this application patent shall be subject to the appended claims, and the specification can be used to explain the content of the claims.

Claims

1. An amine microcapsule, characterized in that: It comprises a core and a capsule shell covering the core; The core is composed of a polymer amine compound; the polymer amine compound has a molecular weight of 2500 g / mol to 3500 g / mol and a viscosity of 350 mPa·s to 450 mPa·s; The capsule shell comprises polyurea; the raw materials for preparing the polyurea comprise the polymer amine compound, isocyanate compound and aromatic fatty amine compound; the aromatic fatty amine compound has a molecular weight of 100 g / mol to 200 g / mol and a viscosity of 5 mPa·s to 10 mPa·s.

2. The amine microcapsule according to claim 1, characterized in that: At least one of the following conditions is met: (1) The ratio of the thickness of the capsule shell to the particle size of the amine microcapsule is 1-2:100; (2) The particle size of the amine microcapsules is 1 μm to 200 μm.

3. The amine microcapsule according to claim 1, characterized in that: The core portion comprises at least 90% by mass of the polymer amine compound.

4. The amine microcapsule according to any one of claims 1 to 3, characterized in that: At least one of the following conditions is met: (1) The polymer amine compounds of the core and the capsule shell each independently include a polyether amine compound; (2) The isocyanate compound includes dicyclohexylmethane diisocyanate; (3) The aromatic aliphatic amine compounds include m-xylylenediamine.

5. A method for preparing amine microcapsules, characterized in that: The steps include: mixing an aromatic aliphatic amine compound and a high molecular weight amine compound to obtain a homogeneous mixture; dissolving an isocyanate compound, a surfactant and a catalyst in a solvent to obtain a reaction solution; preparing the homogenous mixture into microdroplets, and receiving the microdroplets with a reaction solution to obtain primary microcapsules; The initial microcapsules are stirred at a first temperature for a first time to obtain amine microcapsules; the amine microcapsules include a core and a capsule shell covering the core; the core comprises a portion of the polymer amine compound; the polymer amine compound has a molecular weight of 2500 g / mol to 3500 g / mol and a viscosity of 350 mPa·s to 450 mPa·s; the capsule shell comprises polyurea; the raw materials for preparing the polyurea include a portion of the polymer amine compound, the isocyanate compound and the aromatic aliphatic amine compound; the aromatic aliphatic amine compound has a molecular weight of 100 g / mol to 200 g / mol and a viscosity of 5 mPa·s to 10 mPa·s; Wherein, the first temperature is 40° C. to 70° C., the stirring speed is 80 rpm to 120 rpm, and the first time is 3 h to 5 h.

6. The preparation method according to claim 5, characterized in that: At least one of the following conditions is met: (1) The particle size of the microdroplets is 1 μm to 200 μm; (2) The concentration of the isocyanate compound in the reaction solution is 0.08-0.2 g / mL.

7. The preparation method according to claim 5, characterized in that: At least one of the following conditions is met: (1) The weight ratio of the polymer amine compound to the aromatic aliphatic amine compound is 9:1 to 5:5; (2) The weight ratio of the isocyanate compound, the surfactant and the catalyst is 4-10:1:0.04-0.

06.

8. The preparation method according to any one of claims 5 to 7, characterized in that: At least one of the following conditions is met: (1) The surfactant includes a non-ionic polymer surfactant; (2) The catalyst includes triethylenediamine; (3) The solvent is selected from a non-polar solvent; optionally, the non-polar solvent includes at least one of hexadecane, liquid paraffin oil and mineral oil.

9. The preparation method according to any one of claims 5 to 7, characterized in that: The method of preparing the homogenous mixture into microdroplets includes electrostatic spraying; The voltage of the electrostatic spray is 11 kV~18 kV, and the spray rate is 0.1~5 mL / h.

10. Use of the amine microcapsule according to any one of claims 1 to 3 in the preparation of a curing agent.

Images