Experimental study on Preparation of the hottest e

2022-07-28
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Experimental study on the preparation of epoxy potting curing agent

Abstract: a new type of aliphatic amine tab was chemically modified to prepare a special epoxy curing agent for potting. A kind of epoxy potting compound was prepared with epoxy resin, flame retardant and toughener. Its formula, preparation process and properties were discussed

key words: epoxy curing agent for potting; Flame retardant; Toughening agent; Epoxy potting material

epoxy resin is an excellent thermosetting resin with a wide range of applications. Its transformation from linear oligomer to body structure must be checked by the curing agent to see whether each force drawn can be completed by finding its force application object

excellent curing agent can endow epoxy resin cured products with excellent physical and mechanical properties, bonding properties, heat resistance, chemical resistance and electrical insulation properties, so they are widely used in various fields of national economy

in recent years, with the continuous development of the electronic and electrical industry, epoxy resin is most widely used in different electrical aspects. In the packaging of electronic components, transformers, current transformers, motors, etc., it plays a role in supporting and insulating the packaged electronic products, and also plays a role in heat transfer, heat dissipation, moisture resistance, flame retardance, etc. for the sealed components

at present, the requirements for the performance of epoxy resin cured products are becoming higher and higher. Many electrical insulation materials, casting bodies and electrical components' potting and encapsulating materials are required to have flexibility and flame retardancy. However, ordinary epoxy potting materials have high elastic modulus, low impact resistance, brittle and easy to crack, and do not have flame retardancy. Therefore, to solve the problem of how to change the brittleness of epoxy potting materials and increase the flame retardancy, we selected the aliphatic polyamine (2,3 dimethyl) dibutyltriamine (TAB) with four methyl branches, and synthesized a modified amine curing agent by ourselves, which can be cured at room temperature together with epoxy resin, reactive flame retardant, toughener, diluent and curing promoter Epoxy potting material with certain flexibility and flame retardancy

this is another phenomenon of structural readjustment. 1 experimental part

1.1 raw materials and instruments

1.1.1 raw materials: (2,3 dimethyl) dibutyltriamine (TAB), Henan natural selection Industry Co., Ltd; Acrylonitrile, Daqing Petrochemical; Epoxy resin E-44, Langfang nuoxin Chemical Co., Ltd; Brominated epoxy resin ex-40 (Chenguang Research Institute of chemical industry); Small molecule epoxide and active diluent (imported); Curing agent (self-made); Accelerator (commercially available), the above raw materials are industrial grade

1.1.2 instrument: four mouth flask; Return condensing pipe; Electric Blender; thermometer. NDJ-1 rotary viscometer; Bunsen lamp (tube length: 100mm, inner diameter: 9.5 ± 0.5mm); Simply supported beam impact testing machine (40kg hammer); Lj5000a tension machine, reverser; Zc36 megger; Qm102b type Q form; High voltage test transformer (5KVA), jc4 dielectric breakdown device (1kVA)

1.2 preparation of curing agent

1.2.1 reaction mechanism

in this experiment, the active hydrogen on the amino group in the tab structure is partially added with the small molecular epoxy group for hydroxyalkylation and partially added with the double bond of acrylonitrile for Cyanoethylation. (the reaction formula is omitted)

both hydroxyalkylation and Cyanoethylation can reduce the toxicity of fatty polyamines, reduce the melting point and improve the color. Hydroxyalkylation can also promote curing due to the introduction of hydroxyl group, but Cyanoethylation reduces the reaction activity. Therefore, hydroxyalkylation and Cyanoethylation have their own advantages and complement each other, so as to achieve the comprehensive effect of low melting point, low toxicity and flexibility. The connection should be reliable

1.2.2 preparation process

put an appropriate amount of (2,3 dimethyl) dibutyltriamine (TAB) into a four port flask, raise the temperature in the water bath to ℃, drop a measured amount of small molecular epoxy, and react for 1 ~ 2 hours. The reaction solution is cooled to ℃, and the measured acrylonitrile is dropped. After dropping, the reaction continues to be stirred at constant temperature for 1 ~ 2 hours. The temperature is reduced, the reaction is stopped, and the product is released. See Table 1 for technical indicators

(to be continued)

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