阅读说明：本技术 一种用于环氧树脂的微胶囊快速固化剂的制备方法 (Preparation method of microcapsule rapid curing agent for epoxy resin ) 是由 徐忠海 赫晓东 蔡朝灿 白玉娇 王荣国 刘文博 董旭伦 于 2019-12-02 设计创作，主要内容包括：一种用于环氧树脂的微胶囊快速固化剂的制备方法,它涉及固化剂制备领域,本发明的目的为了解决目前微胶囊固化剂不适于环氧树脂预浸料,与环氧树脂结合后自润滑性能差；且制备工艺复杂,固化剂壁材多为耐热性较低的聚合物易于分解或挥发的问题,以活性固化剂为芯材、聚己内酯(PCL)为壁材,可以使环氧树脂型预浸料室温贮存期大大增长,不仅可以解决单组份环氧树脂快速固化的能力,也能提高材料材料的贮存期,适用于制备碳纤维、玻璃纤维等纤维及其织物增强的环氧树脂预浸料。本发明应用于汽车、运动制品及航空航天等领域。(The invention discloses a preparation method of a microcapsule rapid curing agent for epoxy resin, which relates to the field of curing agent preparation and aims to solve the problems that the existing microcapsule curing agent is not suitable for epoxy resin prepreg and has poor self-lubricating property after being combined with epoxy resin; the preparation process is complex, most of curing agent wall materials are easy to decompose or volatilize polymers with low heat resistance, the active curing agent is used as a core material, and Polycaprolactone (PCL) is used as a wall material, so that the room-temperature storage period of the epoxy resin type prepreg is greatly prolonged, the capability of rapidly curing the single-component epoxy resin can be solved, the storage period of the material can be prolonged, and the preparation method is suitable for preparing the epoxy resin prepreg reinforced by fibers such as carbon fibers and glass fibers and fabrics thereof. The invention is applied to the fields of automobiles, sports products, aerospace and the like.)

1. A preparation method of a microcapsule rapid curing agent for epoxy resin is characterized in that a core material of the microcapsule rapid curing agent is an active curing agent, and a wall material of the microcapsule rapid curing agent is polycaprolactone; the method comprises the following steps:

firstly, mixing an active curing agent and polycaprolactone, dissolving the mixture in an organic solvent, and performing ultrasonic dispersion until the curing agent and the polycaprolactone are completely dissolved to form an oil phase solution;

dissolving a hydrophilic dispersant in water to form a water phase solution; mixing the water phase solution and the oil phase solution, and stirring at high speed in a high-speed homogenizer to form an oil-in-water emulsion;

adding the formed oil-in-water emulsion into a stabilizer, stirring and heating to volatilize the organic solvent, forming a film on a water-oil interface by polycaprolactone in an oil phase, and wrapping an active curing agent to form a microcapsule;

fourthly, carrying out suction filtration on the solution containing the curing agent to form the microcapsule, placing the precipitate after suction filtration in a vacuum drying oven, and drying to obtain the microcapsule rapid curing agent;

wherein the stabilizing agent is nano silicon dioxide particles.

2. The preparation method of the microcapsule rapid curing agent for epoxy resin as claimed in claim 1, wherein the mass percentage of the nano silica particles is 1-1.5%.

3. The method for preparing a microcapsule fast curing agent for epoxy resin according to claim 1 or 2, wherein the formed oil-in-water emulsion is added to a stabilizer, and the organic solvent is volatilized by heating at a reaction temperature of 25 to 30 ℃ and a stirring speed of 600 rpm.

4. The method for preparing the microcapsule fast curing agent for epoxy resin according to claim 1, wherein the active curing agent is imidazole or its derivatives.

5. The method of claim 4, wherein the active imidazole or its derivative is imidazole, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, benzimidazole, 2-phenyl-4-methylimidazole or 2-ethyl-4-methylimidazole.

6. The preparation method of the microcapsule fast curing agent for epoxy resin as claimed in claim 1 or 4, wherein the mass ratio of the active curing agent to polycaprolactone is 5: 1-0.5: 1.

7. the method for preparing the microcapsule fast curing agent for epoxy resin according to claim 1, wherein the organic solvent is an organic substance miscible with polycaprolactone.

8. The method for preparing the microcapsule fast curing agent for epoxy resin according to claim 1 or 7, wherein the organic solvent is dichloromethane.

9. The method for preparing the microcapsule fast curing agent for epoxy resin according to claim 1, wherein the dispersant is sodium dodecyl sulfate, tween-80 or OP-10; the addition amount of the dispersant is 0.5 to 5 percent of the water phase solution.

10. The method for preparing a microcapsule fast curing agent for epoxy resin according to claim 1 or 9, wherein the volume ratio of the aqueous phase solution to the oil phase solution is 3: 1.

Technical Field

The invention belongs to the technical field of curing agent preparation, and particularly relates to a preparation method of a microcapsule rapid curing agent.

Background

The epoxy resin is a typical thermosetting resin, a molecular chain contains more than two epoxy groups, the epoxy resin is viscous liquid at normal temperature, and the epoxy resin and a curing agent are cured and crosslinked to form a three-dimensional network type macromolecular structure. Epoxy resin has excellent mechanical and physical properties, good chemical stability, low molding shrinkage and good dimensional stability, and therefore, the epoxy resin has been widely used in the fields of electronic packaging, construction, aerospace, automobiles and the like. In industrial production, the epoxy resin and the curing agent are required to be stored separately, and then are prepared again when being used, and are uniformly stirred and cured, so that the efficiency of producing epoxy resin products is greatly reduced, and the use of the epoxy resin is limited. If the epoxy resin prepreg is prepared for the next production of epoxy resin, the production speed can be greatly improved, and the quality of the prepreg can determine the performance of the product to a great extent. Generally, epoxy resin prepregs have a short storage life at room temperature and need to be stored at low temperature, which increases the difficulty and cost of transportation. If a curing agent with low curing activity is used, the curing temperature of the curing agent and epoxy resin is too high, and the problems of large curing internal stress, long forming period, high energy consumption, high manufacturing cost and the like exist. Therefore, the latent curing agent for curing the epoxy resin at the medium and low temperature needs to have proper activity, good latent period and excellent comprehensive performance.

In recent years, microcapsules have been developed greatly, and the special core-shell structure of the microcapsules provides protection for the inner core material, prevents the core material from being affected by the external environment, and can control the release of the core material by pressurization, temperature rise and other methods. The curing agent coated by the microcapsule technology can be used for curing epoxy resin, is simple and convenient to prepare and flexible to operate, and realizes the application of the curing agent in epoxy resin latent prepreg, adhesive, packaging materials of semiconductor devices, self-healing and the like. Therefore, the microcapsule technology can be applied to the preparation of latent curing agents to coat curing agent molecules with high activity, so as to greatly prolong the room-temperature storage period of a system and realize the rapid curing of epoxy resin at medium and low temperature.

The research on microcapsule curing agents is more, Dong Ho Lee adopts a spray drying method to coat imidazole curing agents to form microcapsules, the content of imidazole in the microcapsules can reach 50% by measuring TGA and EA, the microcapsules can not be cured within 15 days at room temperature, and the microcapsules show good latency. The micro-capsule curing agent is prepared by taking PMF (poly melamine-formaldehyde resin) as a shell material and TMPMP (trimethylolpropane tris (3-mercaptopropionate)) as a core material by virtue of an in-situ emulsion polymerization method. Influences of the type and the mixing amount of the emulsifier, the mass ratio of the core to the shell, the reaction temperature, the reaction time, the pH value and the like on the particle size and the stability of the synthesized microcapsule are discussed, the particle size of the prepared microcapsule is 50-125 mu m, and the microcapsule has good sealing property and heat resistance and can achieve a good curing effect at the temperature of more than 0 ℃.

However, these curing agents have complicated preparation processes, sometimes require pH adjustment, heating and cooling to cause reaction, require special reagents, and have poor experimental repeatability. And most of curing agent wall materials are polymers with low heat resistance, are easy to decompose or volatilize, are not suitable for preparing epoxy resin prepreg, and have poor self-lubricating property when added into epoxy resin.

Because the self-abrasion resistance of the epoxy resin is poor, an oily substance is coated as a core material, the core material is prepared into microcapsules, and the microcapsules are mixed with the epoxy resin, so that the oily substance is released through the release of the microcapsules, and the epoxy resin is lubricated. However, if a non-oil core material is used, lubrication is difficult to be performed by the core material, and the wear resistance of the epoxy resin is improved.

Disclosure of Invention

The invention aims to solve the problems that the existing microcapsule curing agent is not suitable for epoxy resin prepreg and has poor self-lubricating property after being combined with epoxy resin; the preparation process is complex, and the problem that the curing agent wall material is easy to decompose or volatilize mostly is the polymer with lower heat resistance, so the preparation method of the microcapsule rapid curing agent for the epoxy resin is provided.

The invention relates to a preparation method of a microcapsule quick curing agent for epoxy resin, wherein a core material of the microcapsule quick curing agent is an active curing agent, and a wall material of the microcapsule quick curing agent is polycaprolactone; the method comprises the following steps:

firstly, mixing an active curing agent and polycaprolactone, dissolving the mixture in an organic solvent, and performing ultrasonic dispersion until the curing agent and the polycaprolactone are completely dissolved to form an oil phase solution;

dissolving a hydrophilic dispersant in water to form a water phase solution; mixing the water phase solution and the oil phase solution, and stirring at high speed in a high-speed homogenizer to form an oil-in-water emulsion;

adding the formed oil-in-water emulsion into a stabilizer, stirring and heating to volatilize the organic solvent, forming a film on a water-oil interface by polycaprolactone in an oil phase, and wrapping an active curing agent to form a microcapsule;

fourthly, carrying out suction filtration on the solution containing the curing agent to form the microcapsule, placing the precipitate after suction filtration in a vacuum drying oven, and drying to obtain the microcapsule rapid curing agent;

wherein the stabilizing agent is nano silicon dioxide particles.

The invention realizes the solvent volatilization method of microencapsulation by a physical method, and has the advantages of no interface polymerization method and no phase separation method. And Polycaprolactone (PCL) with good affinity with epoxy resin is used for preparing the microcapsules, so that the mechanical property of an epoxy resin product is not reduced, the glass transition temperature of the PCL is 60 ℃, and the storage property of the microcapsules is good at normal temperature. The invention can quickly cure the epoxy resin, solves the two problems of quick curing of the single-component epoxy resin and prolonging the storage life of the material, is suitable for preparing the epoxy resin prepreg reinforced by fibers such as carbon fibers, glass fibers and the like and fabrics thereof, and can be applied to the fields of automobiles, sports products, aerospace and the like.

According to the invention, the core material and the wall material are prepared into the oil phase, and are mixed with the water phase of the dispersing agent, and the microcapsule is prepared by means of suction filtration and organic solvent volatilization. Most of the existing microcapsule wall materials are polymers with low heat resistance, and the existing microcapsule wall materials are easy to decompose or volatilize in advance in the storage process of epoxy resin, so that the storage period of the epoxy resin is reduced. In addition, the existing microcapsule wall material is easy to break in advance in the epoxy resin curing process, so that the epoxy resin curing reaction is caused in advance, and the performance of the cured epoxy resin is influenced. The microcapsule wall material adopted by the invention is thermoplastic high polymer polycaprolactone, so that the problems can be effectively avoided. According to the invention, the nano silicon dioxide particles are added, so that the prepared microcapsule is embedded into the epoxy resin, the lubricating composite material is obtained, the self-lubricating composite coating has excellent anti-friction performance, and the anti-friction and wear-resistant performances of the epoxy resin material are obviously improved.

Detailed Description