Epoxy glue solution dispersion liquid of microcapsules and preparation method of epoxy glue solution dispersion liquid

Abstract

The invention relates to the technical field of preparation of high polymer materials, in particular to epoxy glue dispersion liquid of microcapsules and a preparation method of the epoxy glue dispersion liquid. The preparation method of the epoxy glue solution dispersion liquid of the microcapsule comprises the following steps: mixing the dispersion liquid of an organic solvent of the microcapsule with an epoxy resin monomer to obtain a mixed glue solution; and carrying out vacuum drying treatment on the mixed glue solution to obtain the epoxy glue solution dispersion liquid of the microcapsule. The epoxy glue dispersion liquid of the microcapsule is uniformly dispersed, the preparation method is simple and convenient, and the application range is wide.

Description

Technical Field

[0001] This application relates to the technical field of polymer material preparation, and particularly relates to an epoxy adhesive liquid dispersion of microcapsules and a preparation method thereof. Background Art

[0002] Polymer materials, also known as polymeric materials, are materials composed of a polymer compound as the matrix and other additives (such as fillers, plasticizers, stabilizers, colorants, etc.). A polymer compound is a compound formed by numerous atoms or atomic groups mainly through covalent bonds and having a relative molecular weight of more than ten thousand, and its molecular structure is usually a long-chain or network structure formed by repeating structural units connected through covalent bonds.

[0003] Epoxy resin refers to an organic polymer compound containing two or more epoxy groups in its molecule. Due to its excellent mechanical properties, chemical stability, and good adhesion, it has been widely used in industries such as construction, aviation, automotive, and electronics. The types of functional fillers added to epoxy resin are extremely rich, and their morphological sizes are diverse. For each type of functional filler with different morphological sizes, according to its morphological size and the final dispersion requirements, effective dispersion methods need to be formed. For example, when using nano-fillers such as carbon nanotubes to enhance and toughen the epoxy resin matrix, methods such as ultrasonic dispersion, homogenizer dispersion, planetary ball milling dispersion, etc. are usually used to finally form a mixture with uniform dispersion of nano-fillers. For macroscopic fillers with larger sizes such as short carbon fibers or long carbon fibers, uniform dispersion can be achieved by mechanically stirring the fibers into the epoxy matrix.

[0004] Microcapsules are tiny particles that encapsulate active substances in a polymer shell layer and can release their internal active ingredients under specific conditions. By adding microcapsules to epoxy adhesive liquid, various different integrations of epoxy adhesive liquid can be achieved, such as self-healing, anti-corrosion, flame retardancy, etc. When the microcapsules are relatively large, the dry microcapsules can be directly added to the epoxy matrix, and a uniformly dispersed mixture can be obtained through simple stirring. When the particle size of the microcapsules is small (for example, the particle size ≤ 100 μm), the surface area of the microcapsules increases sharply, resulting in their very easy agglomeration and caking, and it is not easy to uniformly disperse in the epoxy adhesive liquid. At the same time, due to the structural characteristics of the microcapsules, in order to avoid rupture of the capsule shell, conventional mechanical dispersion methods (such as ultrasonic dispersion, homogenizer dispersion, planetary ball milling dispersion, etc.) are not applicable.

[0005] Therefore, developing a preparation method for the epoxy adhesive liquid dispersion of microcapsules is crucial for functionalizing and modifying epoxy adhesive liquid using microcapsules. Summary of the Invention

[0006] Based on this, one or more embodiments of this application provide an epoxy adhesive liquid dispersion of microcapsules and a preparation method thereof.

[0007] The technical solution of this application includes the following content:

[0008] An embodiment of this application provides a method for preparing a dispersion of epoxy adhesive liquid of microcapsules, which includes the following steps:

[0009] Mix a dispersion of organic solvent of microcapsules and epoxy adhesive liquid to obtain a mixed adhesive liquid;

[0010] Perform vacuum drying treatment on the mixed adhesive liquid to obtain the dispersion of epoxy adhesive liquid of microcapsules;

[0011] The particle size of the microcapsules ≤ 100 μm, and the organic solvent is selected from alicyclic hydrocarbon compounds.

[0012] The method for preparing the dispersion of epoxy adhesive liquid of microcapsules in this application can conveniently obtain a mixed adhesive liquid without damaging the microcapsules by first mixing the dispersion of organic solvent of microcapsules and epoxy resin monomer, and then taking the mixed adhesive liquid by vacuum drying to remove the organic solvent therein to obtain the dispersion of epoxy adhesive liquid of microcapsules. Using this preparation method solves the problem that dried microcapsules are prone to agglomeration and difficult to disperse evenly in epoxy adhesive liquid, and can achieve dispersion without the need for special mechanical stirring. The organic solvent can be conveniently removed by vacuum drying. The preparation method is simple and efficient, and is suitable for preparing dispersions of epoxy adhesive liquid of various types and particle sizes of microcapsules.

[0013] An embodiment of this application also provides a dispersion of epoxy adhesive liquid of microcapsules obtained by using the above-mentioned preparation method. Using the above-mentioned preparation method to prepare the dispersion of epoxy adhesive liquid of microcapsules has the advantages of uniform dispersion and wide applicability. Description of the Drawings

[0014] In order to more clearly illustrate the specific embodiments of this application or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0015] Figure 1 It is the scanning electron microscope (SEM) image of the microcapsules in Embodiment 1 of this application. Figure 1 Among them, (a) is the morphology of the microcapsules before separation and collection after synthesis, (b) is the cross-sectional view of the microcapsules after being cut, and (c) is the enlarged wall thickness of the capsule.

[0016] Figure 2 It is the physical picture of the microcapsules in Comparative Example 1 of this application after separation and drying.

[0017] Figure 3 Optical microscope image of the n - hexadecane dispersion of the microcapsules of Comparative Example 2 of the present application.

[0018] Figure 4 Optical microscope image of the cyclohexane dispersion of the microcapsules of Comparative Example 3 of the present application.

[0019] Figure 5 Optical microscope image of the cyclohexane dispersion of the microcapsules of Example 1 of the present application.

[0020] Figure 6 Optical microscope image of the epoxy adhesive blend of the microcapsules of Comparative Example 1 of the present application. Figure 6 Among them, (a) shows the dispersion of large - agglomerated microcapsules in the adhesive, (b) shows the dispersion of partially agglomerated microcapsules in the adhesive, and (c) shows the dispersion of a small portion of microcapsules agglomerated in the adhesive.

[0021] Figure 7 Optical microscope image of the epoxy adhesive dispersion of the microcapsules of Example 1 of the present application. Figure 7 Among them, (a) shows the situation of cyclohexane - assisted dispersed microcapsules in the adhesive, and (b) shows the dispersion of microcapsules in the adhesive after removing cyclohexane.

[0022] Figure 8 SEM image of the microcapsules of Example 2 of the present application. Figure 6 Among them, (a) is the cross - sectional view after the microcapsule is cut, and (b) is the enlarged wall thickness of the capsule.

[0023] Figure 9 Optical microscope image of the epoxy adhesive dispersion of the microcapsules of Example 2 of the present application.

[0024] Figure 10 Optical microscope image of the epoxy adhesive dispersion of the microcapsules of Example 3 of the present application.

[0025] Figure 11 Optical microscope image of the epoxy adhesive dispersion of the microcapsules of Example 4 of the present application.

[0026] Figure 12 Optical microscope image of the epoxy adhesive dispersion of the microcapsules of Example 5 of the present application.

[0027] Figure 13 Optical microscope image of the epoxy adhesive dispersion of the microcapsules of Example 6 of the present application.

[0028] Figure 14 Optical microscope image of the epoxy adhesive dispersion of the microcapsules of Example 7 of the present application.

[0029] Figure 15 Optical microscope picture of the epoxy adhesive liquid dispersion of the microcapsules in Example 8 of this application.

[0030] Figure 16 Optical microscope picture of the epoxy adhesive liquid dispersion of the microcapsules in Example 9 of this application. Detailed implementation manners

[0031] The present application will be further elaborated below in conjunction 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.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the description of this application in this specification are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0033] Term

[0034] Unless otherwise stated or there is a contradiction, the terms or phrases used herein have the following meanings:

[0035] 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 connecting at least three items with 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.

[0036] In this application, "further" is used for descriptive purposes, indicating a difference in content, but should not be construed as a limitation on the protection scope of this application.

[0037] 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 listing description and should be understood not to constitute a closed limitation on quantity.

[0038] In this application, among the technical features described in an open-ended manner, it includes both a closed technical solution composed of the listed features and an open technical solution containing the listed features.

[0039] In this application, regarding numerical intervals (i.e., numerical ranges), unless otherwise specified, the optional numerical values are considered continuous within the above numerical intervals, and include the two numerical endpoints of this numerical range (i.e., the minimum value and the maximum value), 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.

[0040] The temperature parameter in this application, unless otherwise specified, allows both constant temperature treatment and variation within a certain temperature range. 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.

[0041] In this application, the weight can be mass units well-known in the chemical industry such as μg, mg, g, kg, etc.

[0042] In this application, unless otherwise specified, when it comes to dimensions, particle sizes, and diameters, it generally refers to the average value.

[0043] The embodiments of this application provide a method for preparing a dispersion of epoxy adhesive liquid of microcapsules, including the following steps:

[0044] Mix a dispersion of the organic solvent of the microcapsules and the epoxy adhesive liquid to obtain a mixed adhesive liquid;

[0045] Perform vacuum drying treatment on the mixed adhesive liquid to obtain a dispersion of epoxy adhesive liquid of microcapsules;

[0046] The particle size of the microcapsules ≤ 100 μm, and the organic solvent is selected from alicyclic hydrocarbon compounds.

[0047] The preparation method of the epoxy adhesive liquid dispersion of the microcapsules of the present application is to first mix the organic solvent dispersion of the microcapsules and the epoxy resin monomer, so that the mixed adhesive liquid can be conveniently obtained without damaging the microcapsules. Then, the mixed adhesive liquid is subjected to vacuum drying to remove the organic solvent therein, and the epoxy adhesive liquid dispersion of the microcapsules is obtained. By adopting this preparation method, the problems that the dried microcapsules are prone to agglomeration and difficult to be evenly dispersed in the epoxy adhesive liquid are solved, and dispersion can be achieved without using special mechanical stirring. The organic solvent can not only be used as a dispersant and a transfer agent at the same time, but also can be conveniently removed by vacuum drying. The preparation method is simple and efficient, and is suitable for preparing the epoxy adhesive liquid dispersions of various types and particle sizes of microcapsules.

[0048] In some embodiments, the microcapsules include a core part and a shell covering the core part;

[0049] The composition of the core part includes a liquid material.

[0050] Further, the liquid material includes a liquid amine curing agent.

[0051] Further, the liquid amine curing agent includes at least one of ethylenediamine condensate, polyetheramine, aliphatic amine, polypropyleneamine, and aromatic amine.

[0052] In some embodiments, the epoxy adhesive liquid includes an epoxy resin monomer, an epoxy curing agent, an epoxy diluent, and an epoxy functional filler.

[0053] In some embodiments, the thickness of the shell is 0.1 μm to 1 μm. Optionally, the thickness of the shell can be 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, etc.

[0054] In some embodiments, the ratio of the thickness of the shell to the particle size of the microcapsules is 0.003 to 0.03:1. Optionally, the ratio of the thickness of the shell to the particle size of the microcapsules can be 0.003:1, 0.005:1, 0.008:1, 0.01:1, 0.015:1, 0.02:1, 0.025:1, 0.03:1, etc.

[0055] In some embodiments, the composition of the capsule shell includes polyurea. The polyurea of the present application is prepared by a polycondensation reaction of an amine compound and an isocyanate compound. By way of example, the amine compound can be an ethylenediamine condensate, a polyetheramine, a fatty amine, a polypropyleneamine, an aromatic amine, etc. The isocyanate compound can be an aromatic isocyanate such as diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), etc., or an aliphatic isocyanate such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), trimethylhexane diisocyanate (TMXDI), etc.

[0056] In some embodiments, the organic solvent includes at least one of cyclohexane, cycloheptane, cyclooctane, cyclodecane, and decalin. The above solvents can not only be used as dispersants to disperse the microcapsules in the epoxy adhesive solution, but also do not cause agglomeration during the vacuum drying process. Preferably, it is cyclohexane, which can be used as both a dispersant and a transfer agent at the same time, and has a better dispersion effect and is more volatile.

[0057] In some embodiments, the mass concentration of the dispersion of the organic solvent of the microcapsules is 40% - 60%. Optionally, the mass concentration of the dispersion of the organic solvent of the microcapsules can be 40%, 45%, 50%, 55%, 60%, etc.

[0058] In some embodiments, the mass ratio of the microcapsules in the epoxy adhesive solution dispersion of the microcapsules is 0.5% - 50%. Optionally, the mass ratio of the microcapsules in the epoxy adhesive solution dispersion of the microcapsules can be 0.5%, 1%, 5%, 10%, 20%, 30%, 40%, 45%, 50%, etc.

[0059] In some embodiments, the step of mixing the dispersion of the organic solvent of the microcapsules and the epoxy adhesive monomer to obtain a mixed adhesive solution includes:

[0060] After mixing the dispersion of the organic solvent of the microcapsules and the epoxy adhesive monomer, stir at a first stirring rate for a first time to obtain a mixed adhesive solution;

[0061] The first stirring rate is 80 rpm - 120 rpm, and the first time is 10 min - 20 min.

[0062] In some embodiments, the step of subjecting the mixed adhesive solution to vacuum drying treatment includes:

[0063] Subject the mixed adhesive solution to treatment at a first vacuum degree for a second time;

[0064] The first vacuum degree is 0.005 MPa - 0.05 MPa, and the second time is 1 h - 3 h.

[0065] The embodiment of the present application also provides an epoxy adhesive liquid dispersion for preparing the microcapsules obtained by the above preparation method. The epoxy adhesive liquid dispersion for preparing the microcapsules is prepared by using the above preparation method, and has the advantages of uniform dispersion and wide applicability.

[0066] The following are some specific embodiments.

[0067] For the experimental parameters not specified in the following specific embodiments, the guidance given in the present application document shall be preferentially 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.

[0068] The raw materials and reagents involved in the following specific embodiments can be obtained commercially, or can be prepared by those skilled in the art according to known means.

[0069] Raw materials:

[0070] TEPA, chemically named tetraethylenepentamine, was purchased from Macklin Chemical Reagent Co., Ltd.;

[0071] Arlacel P135 (trade name) was purchased from Croda International Plc;

[0072] HMDI, chemically named 4,4'-dicyclohexylmethane diisocyanate, was purchased from Wanhua Chemical Group Co., Ltd.;

[0073] BADGE, chemically named bisphenol A diglycidyl ether, was purchased from Macklin Chemical Reagent Co., Ltd.

[0074] I. Preparation of epoxy adhesive liquid dispersion for microcapsules

[0075] Example 1

[0076] This example provides an epoxy adhesive liquid dispersion for the microcapsules of the present application, and its preparation method includes the following steps:

[0077] (1) The amine curing agent tetraethylenepentamine (TEPA) was loaded into a syringe and extruded at a rate of 4.0 mL / h, and atomized under a static voltage of 15 kV to form core liquid micro-droplets. A reaction solution containing 50.0 mL of decalin, 0.5 g of the surfactant Arlacel P135, and 6.0 g of HMDI was used to receive the above core liquid micro-droplets to obtain primary microcapsules, and the mixture was continuously heated and stirred to obtain microcapsules with a relatively thick capsule wall. The process of heating and stirring included: stirring at 40 °C for 1 h, then stirring at 50 °C for 2 h, and then stirring at 60 °C for 2 h. Subsequently, the above reaction solution (in which the microcapsules were dispersed) was filtered to obtain microcapsules. After washing the impurities on the surface of the microcapsules with cyclohexane, the microcapsules were transferred to a container and cyclohexane was added to obtain a cyclohexane dispersion of the microcapsules with a mass concentration of 50%.

[0078] (2) Pour 10 mL of the cyclohexane dispersion of microcapsules into 20 g of the epoxy monomer bisphenol A diglycidyl ether (BADGE), mix well with a glass rod for 10 min to obtain a mixed adhesive solution.

[0079] (3) Place the mixed adhesive solution in a vacuum chamber, adjust the internal absolute pressure of the vacuum chamber to 0.02 MPa to allow cyclohexane to volatilize from the mixture. After about 2 h, cyclohexane has completely volatilized, and finally an epoxy adhesive solution with uniformly dispersed microcapsules is obtained. The mass ratio of microcapsules in the mixture is about 10 wt%.

[0080] Comparative Example 1

[0081] (1) After preparing the cyclohexane dispersion of microcapsules using the same steps as in step (1) of Example 1, filter and dry to obtain dry microcapsules.

[0082] (2) Mix 1 g of microcapsules and 10 g of BADGE, and stir with a glass rod for 10 min to obtain a mixed solution of microcapsule epoxy adhesive.

[0083] Comparative Example 2

[0084] It is basically the same as Example 1, except that paraffin oil is used as the dispersion liquid of microcapsules. The remaining steps are the same as in Example 1. Although the cyclohexane dispersion of microcapsules can be evenly dispersed when added to the epoxy adhesive, agglomeration occurs during vacuum drying.

[0085] Comparative Example 3

[0086] It is basically the same as Example 1, except that the mass concentration of the cyclohexane dispersion of microcapsules obtained in step (1) is 80%. The remaining steps are the same as in Example 1.

[0087] Example 2

[0088] This example provides an epoxy adhesive dispersion of the microcapsules of the present application. Its preparation method is basically the same as that of Example 1, except that: after obtaining the primary microcapsules in step (1), heating and stirring are not continued, and the remaining operations are the same to obtain a cyclohexane dispersion containing primary microcapsules. The remaining steps are the same as in Example 1.

[0089] Example 3

[0090] This example provides an epoxy adhesive dispersion of the microcapsules of the present application. Its preparation method is basically the same as that of Example 1, except that: in step (2), paddle-type mechanical stirring is carried out at 100 rpm for about 15 min. The remaining steps are the same as in Example 1.

[0091] Example 4

[0092] This embodiment provides an epoxy adhesive liquid dispersion of the microcapsules of the present application. Its preparation method is basically the same as that of Example 1, except that: in step (1), the spraying rate and voltage for preparing the microcapsules are adjusted to 1 mL / h and 13 kV respectively, and microcapsules with a particle size of about 15 μm are obtained. The remaining steps are the same as those in Example 1.

[0093] Example 5

[0094] This embodiment provides an epoxy adhesive liquid dispersion of the microcapsules of the present application. Its preparation method is basically the same as that of Example 1, except that: in step (1), the spraying rate and voltage for preparing the microcapsules are adjusted to 10 mL / h and 18 kV respectively, and microcapsules with a particle size of about 100 μm are obtained. The remaining steps are the same as those in Example 1.

[0095] Example 6

[0096] This embodiment provides an epoxy adhesive liquid dispersion of the microcapsules of the present application. Its preparation method is basically the same as that of Example 1, except that: the low-polarity and low-boiling-point organic solvent used is replaced with decalin, and the internal absolute pressure in step (3) is changed from 0.02 MPa to 0.005 MPa. The remaining steps are the same as those in Example 1.

[0097] Example 7

[0098] This embodiment provides an epoxy adhesive liquid dispersion of the microcapsules of the present application. Its preparation method is basically the same as that of Example 1, except that: in step (1), the amine curing agent in the microcapsules is replaced with a mixture of tetraethylenepentamine and polyether polyamine (JEFFAMINE T403). The specific steps are as follows: Mix 25 parts of tetraethylenepentamine (TEPA) and 75 parts of polyether polyamine (JEFFAMINE T403) evenly to form a 25TEPA75T403 mixed amine curing agent; After loading the mixed amine curing agent into a syringe, it is extruded at a rate of 6.0 mL / h and atomized under a static voltage of 16 kV to form core liquid micro-droplets. Use a reaction solution containing 50.0 mL of decalin, 0.5 g of surfactant Arlacel P135, and 6.0 g of HMDI to receive the above core liquid micro-droplets, obtain primary microcapsules and continue to heat and stir to obtain microcapsules with a relatively thick capsule wall. The process of heating and stirring includes: stirring at 70 °C for 2 h. Subsequently, filter the above reaction solution (in which the microcapsules are dispersed) to obtain microcapsules. After washing the surface impurities of the microcapsules with cyclohexane, transfer the microcapsules to a container and add cyclohexane to obtain a cyclohexane dispersion of the microcapsules with a mass concentration of 50 w%. The remaining steps are the same as those in Example 1.

[0099] Example 8

[0100] This example provides an epoxy adhesive dispersion of the microcapsules of the present application. Its preparation method is basically the same as that of Example 1, except that: the volume of the cyclohexane dispersion of the microcapsules used in step (2) is changed from 10 mL to 0.5 mL, so that the mass percentage of the microcapsules in the final mixture is reduced to 0.5 wt%. The remaining process is the same as that of Example 1.

[0101] Example 9

[0102] This example provides an epoxy adhesive dispersion of the microcapsules of the present application. Its preparation method is basically the same as that of Example 1, except that: the volume of the cyclohexane dispersion of the microcapsules used in step (2) is changed from 10 mL to 50 mL, so that the mass percentage of the microcapsules in the final mixture is increased to 50 wt%. The remaining process is the same as that of Example 1.

[0103] II. Structural Characterization

[0104] Microscopic structure observation was carried out using a scanning electron microscope, including microcapsule morphology and wall thickness;

[0105] The dispersion of microcapsules in the epoxy adhesive was characterized using an optical microscope.

[0106] The SEM image of the microcapsules of Example 1 is as Figure 1 shown. The particle size of the microcapsules is about 30 μm, and they have good dispersibility during synthesis. The wall thickness is about 0.78 μm. The microcapsules of Comparative Example 1 are as Figure 2 shown. Since the particle size of the microcapsules is small, they agglomerated after separation and drying. The microcapsules of Comparative Example 2 are as Figure 3 shown. In Comparative Example 2, although the cyclohexane dispersion of the microcapsules can be dispersed evenly when added to the epoxy adhesive, agglomeration occurred during vacuum drying. The microcapsules of Comparative Example 3 are as Figure 4 shown. In Comparative Example 3, due to the too high concentration of the microcapsules, the two cannot be mixed evenly when the cyclohexane dispersion of the microcapsules is added to the epoxy adhesive, resulting in agglomeration of the microcapsules.

[0107] The optical microscope picture of the cyclohexane dispersion of the microcapsules of Example 1 is as Figure 5 shown. It can be seen that the microcapsules are evenly dispersed in cyclohexane without agglomeration. The optical microscope picture of the epoxy adhesive mixture of the microcapsules of Comparative Example 1 is as Figure 6 shown. It can be seen that since the dried microcapsules are severely agglomerated by themselves, it is difficult for them to be opened and dispersed in the epoxy adhesive to form a uniformly dispersed epoxy adhesive mixture. The optical microscope picture of the epoxy adhesive dispersion of the microcapsules of Example 1 is as Figure 7 shown, Figure 7In (a), it shows the situation of cyclohexane-assisted dispersed microcapsules in the glue solution, and in (b), it shows the situation of the microcapsules dispersed in the glue solution after removing cyclohexane. It can be seen that in both cases, the small-sized amine microcapsules are well dispersed in the epoxy glue solution.

[0108] The SEM image of the microcapsules in Example 2 is as Figure 8 shown. The particle size of this microcapsule is about 30 μm, and it has good dispersibility during synthesis. The wall thickness of the capsule is about 100 nm. The optical microscope picture of the epoxy glue solution dispersion of the microcapsules in Example 2 is as Figure 9 shown. It can be seen that even though the wall of the microcapsules in Example 2 is relatively thin, they can be evenly dispersed in the epoxy glue solution and do not break during the dispersion process. The optical microscope picture of the epoxy glue solution dispersion of the microcapsules in Example 3 is as Figure 10 shown. It can be seen that when using paddle-type mechanical stirring, the microcapsules can also be evenly dispersed in the epoxy glue solution and do not break during the dispersion process. The optical microscope picture of the epoxy glue solution dispersion of the microcapsules in Example 4 is as Figure 11 shown. In Example 4, the particle size of the microcapsules is about 15 μm. It can be seen that when the particle size of the microcapsules is very small, they can also be evenly dispersed in the epoxy glue solution. The optical microscope picture of the epoxy glue solution dispersion of the microcapsules in Example 5 is as Figure 12 shown. In Example 5, the particle size of the microcapsules is about 100 μm. It can be seen that when the particle size of the microcapsules is relatively large, they can also be evenly dispersed in the epoxy glue solution. The optical microscope picture of the epoxy glue solution dispersion of the microcapsules in Example 6 is as Figure 13 shown. It can be seen that by using different low-polarity and low-boiling-point solvents, the microcapsules can also be evenly dispersed into the epoxy glue solution. The optical microscope picture of the epoxy glue solution dispersion of the microcapsules in Example 7 is as Figure 14 shown. It can be seen that when the core material of the microcapsules in Example 7 is a composite material, they can also be successfully and evenly dispersed in the epoxy glue solution. The optical microscope picture of the epoxy glue solution dispersion of the microcapsules in Example 8 is as Figure 15 shown. It can be seen that when the mass concentration of the microcapsules is relatively low, they can be evenly dispersed in the epoxy glue solution. The optical microscope picture of the epoxy glue solution dispersion of the microcapsules in Example 9 is as Figure 16 shown. It can be seen that when the mass concentration of the microcapsules is relatively high, they can also be evenly dispersed in the epoxy glue solution.

[0109] The characterization results of the above examples and comparative examples show that the preparation method of the present application has a wide range of applications. It can be used to prepare epoxy adhesive liquid dispersions with microcapsules of small particle size, and can also be used to prepare epoxy adhesive liquid dispersions with microcapsules of large particle size. It is applicable to microcapsules with thin capsule walls and also applicable to microcapsules with thick capsule walls. For the materials in the core of the microcapsules, it is applicable to liquid materials and also applicable to solid materials. At the same time, the preparation method of the present application is simple to operate and convenient to use. For example, in the step of stirring and dispersing, it can be manually stirred or mechanically stirred. During the vacuum drying process, the pressure can be adjusted to remove different solvents, indicating that the preparation method of the present application has good practicability and industrial application value.

[0110] All the documents mentioned in the present application are incorporated herein by reference as if each document was individually incorporated by reference. Unless it conflicts with the application purpose and / or technical solution of the present application, the cited documents related to the present application are incorporated by reference in their entirety and for all purposes. When the present application refers to a cited document, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited document are also incorporated by reference. When the present application refers to a cited document, the examples and preferred methods of the relevant technical features cited can also be incorporated as references into the present application, but only to the extent that the present application can be implemented. It should be understood that when the cited content conflicts with the description in the present application, the present application shall prevail or be amended adaptively according to the description in the present application.

[0111] 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 there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0112] The above-described embodiments only represent several implementation manners of the present 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 the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. In addition, it should be understood that after reading the above teachings of the present application, those skilled in the art can make various changes or modifications to the present application, and the equivalent forms obtained also fall within the protection scope of the present 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 the present application are all within the protection scope of the appended claims of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims, and the specification can be used to explain the content of the claims.

Claims

1. A method for preparing an epoxy adhesive liquid dispersion of microcapsules, characterized in that, It includes the following steps: Mix the dispersion of the organic solvent of the microcapsules and the epoxy adhesive solution to obtain a mixed adhesive solution; Perform vacuum drying treatment on the mixed adhesive solution to obtain the epoxy adhesive solution dispersion of the microcapsules; The particle size of the microcapsules ≤ 100 μm, and the organic solvent is selected from alicyclic hydrocarbon compounds.

2. The preparation method according to claim 1, characterized in that, The microcapsules include a core and a shell covering the core; The composition of the core includes a liquid material.

3. The preparation method according to claim 2, wherein Meet at least one of the following conditions: (1) The thickness of the shell is 0.1 μm to 1 μm; (2) The ratio of the thickness of the shell to the particle size of the microcapsules is 0.003 to 0.03:

1.

4. The preparation method according to claim 2, characterized in that, Meet at least one of the following conditions: (1) The composition of the shell includes polyurea; (2) The liquid material includes a liquid amine curing agent; (3) The epoxy adhesive solution includes an epoxy resin monomer, an epoxy curing agent, an epoxy diluent, and an epoxy functional filler.

5. The preparation method according to claim 4, characterized in that, The liquid amine curing agent includes at least one of ethylenediamine condensate, polyetheramine, aliphatic amine, polypropyleneamine, and aromatic amine.

6. According to the preparation method described in any one of claims 1 to 5, characterized in that, The organic solvent includes at least one of cyclohexane, cycloheptane, cyclooctane, cyclodecane, and decalin.

7. According to the preparation method described in any one of claims 1 to 5, it is characterized in that Meet at least one of the following conditions: (1) The mass concentration of the dispersion of the organic solvent of the microcapsules is 40% to 60%; (2) The mass proportion of the microcapsules in the epoxy adhesive solution dispersion of the microcapsules is 0.5% to 50%.

8. According to the preparation method described in any one of claims 1 to 5, characterized in that, The step of mixing the dispersion of the organic solvent of the microcapsules and the epoxy adhesive solution monomer to obtain a mixed adhesive solution includes: After mixing the dispersion of the organic solvent of the microcapsules and the epoxy adhesive solution monomer, stir at a first stirring rate for a first time to obtain the mixed adhesive solution; The first stirring rate is 80 rpm to 120 rpm, and the first time is 10 min to 20 min.

9. According to the preparation method described in any one of claims 1 to 5, characterized in that, The step of performing vacuum drying treatment on the mixed adhesive solution includes: Treat the mixed adhesive solution under a first vacuum degree for a second time; The first vacuum degree is 0.005 MPa to 0.05 MPa, and the second time is 1 h to 3 h.

10. An epoxy adhesive solution dispersion of microcapsules prepared by the preparation method according to any one of claims 1 to 9.

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