Epoxy curing agent (2)

(4) Modified amine curing agents

Although the epoxy resin can be well cured and has better performance, there are many disadvantages. For example, it is difficult to control the epoxy resin if it is difficult to match with the epoxy resin.

Adhesive strength is not high Brittleness Large resistance to medium is not good, overall performance is poor; short pot life. Some room temperature 2 ~ 3H gel, inconvenient operation; most unclear and easy

The carbon dioxide in the air generates the corresponding carbonate, resulting in whitening of the surface of the cured product; avoiding water in storage and use, failure of water absorption, and some foaming

Crystallization at high and low temperature can not be prepared General heating when the curing is large, especially in summer, easy to burst, can not be used more volatile, irritating skin and mucous membranes, pollution

The environment is hazardous to health. Therefore, it is not suitable for polyamines to be used alone. Various methods can be used to obtain high strength, good toughness, low toxicity, low price, and ease of use.

A wide range of new amine curing agents with excellent comprehensive properties.

1, Mannich type modified amine

Mannich-type modified amines are mixtures of Mannich bases produced by the Mannich reaction, also known as amine methylation. The Mannich reaction is a mixture of amines, aldehydes, and phenols that eventually become a mixture of components in the asymmetric condensation process. The amines can be divided into ethylenediamine, diamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethylenepolyamine, isophoronediamine, metaxylylenediamine, metaphenylene diamine. Wait. Aldehydes are mainly formaldehyde, butyraldehyde, p-hydroxybenzaldehyde, and the like. Phenols include phenol, butylphenol, octylphenol, nonylphenol, cresol and the like.

According to the different types, ratios, process routes, reaction conditions and end point control of aminophenols, modified amine curing agents with various types and different properties can be obtained. It has many advantages, such as adjusting the curing speed according to the requirement that the ratio is not strict; the introduction of a phenolic hydroxyl group increases the activity of the curing reaction; the presence of a phenolic structure, improves the heat resistance of the cured material; and makes the solid amine liquid, easy Blended with epoxy resin can be cured at low temperature, humidity or under water quickly; it reduces the volatility, irritation and primordiality of lower amines, and thus Mannich type curing agent has become the most important species of the curing agent.

There are one-step and two-step methods for producing Mannich-type curing agents, and one-step method is more advanced with solid methacrylate (paraformaldehyde). Due to the introduction

The amount of water is small, the amount of waste water generated is also low; the reaction conditions are mild, the reaction time and the dehydration time are shortened, and the energy consumption is greatly reduced, resulting in industrial production;

The product is of high transparency and low cost. If paraformaldehyde is reacted with urea and phenol in a solvent. Preparation of phenol-urea-formaldehyde resin, with B

Diamine reaction can get a new curing agent UPFA.

2. Michael type modified amine

The addition reaction of the active hydrogen of the amine to a, b unsaturated bonds. Known as Michael (Michacl) reaction. The addition of polyamines to acrylonitrile is known as nitrile ethylation

The resulting product was a Michael-type modified amine.

3, epoxy compound amine adducts

Mono-epoxy or di-epoxy compounds react with polyamines to give polyamine adducts. As the relative molecular weight of the adduct increases, the boiling point and viscosity increase volatility and toxicity decreases.

low. With the same amount, the hydroxyl group generated by the addition reaction promotes the curing and can quickly cure the epoxy resin at room temperature. The disadvantages are heat resistance, water resistance, and resistance to media

Poor sex.

(1) Amino-105 epoxy curing agent. Also known as 105 aminating amines from meta-xylylenediamine catalyzed and condensed to produce amines, light yellow transparent and viscous, viscosity 500~1000 mp.s

Check the dosage 30~35 phr. Curing conditions RT*24H or 80°C*3H or 100°C*2H.

(2), KB-2 epoxy curing agent Condensed from fatty amines and aromatic amines, light brownish transparent liquid reference amount 50 ~ 55 phr.

Curing conditions RT*48H or 120°C*2H.

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