阅读说明：本技术 一种非离子型水性环氧树脂固化剂及其制备方法 (Non-ionic waterborne epoxy resin curing agent and preparation method thereof ) 是由 徐友辉 陈自然 王碧 陶果 于 2020-06-15 设计创作，主要内容包括：本发明公开了一种非离子型水性环氧树脂固化剂及其制备方法。该方法包括：(1)将乙二醇二缩水甘油醚溶液升温至60～90℃,然后加入3,4-二甲氧基苯胺溶液,于保护气体氛围中,保温反应3～10h,蒸发浓缩后得乙二醇二缩水甘油醚-3,4-二甲氧基苯胺加成产物；(2)将步骤(1)所得产物搅拌升温至50～70℃,然后加入封端剂,保温反应3～10h后,再进行蒸发浓缩即可。本发明反应条件温和,安全环保,制备得到的固化剂收率高。(The invention discloses a non-ionic waterborne epoxy resin curing agent and a preparation method thereof. The method comprises the following steps: (1) heating the ethylene glycol diglycidyl ether solution to 60-90 ℃, then adding a 3, 4-dimethoxyaniline solution, carrying out heat preservation reaction for 3-10 h in a protective gas atmosphere, and carrying out evaporation concentration to obtain an ethylene glycol diglycidyl ether-3, 4-dimethoxyaniline addition product; (2) and (2) stirring the product obtained in the step (1), heating to 50-70 ℃, adding an end-capping reagent, reacting for 3-10 hours under a heat preservation condition, and then performing evaporation concentration. The method has the advantages of mild reaction conditions, safety, environmental protection and high yield of the prepared curing agent.)

1. A preparation method of a nonionic water-based epoxy resin curing agent is characterized by comprising the following steps:

(1) heating the ethylene glycol diglycidyl ether solution to 60-90 ℃, then adding a 3, 4-dimethoxyaniline solution, carrying out heat preservation reaction for 3-10 h in a protective gas atmosphere, and carrying out evaporation concentration to obtain an ethylene glycol diglycidyl ether-3, 4-dimethoxyaniline addition product; the molar ratio of the ethylene glycol diglycidyl ether to the 3, 4-dimethoxyaniline is 1.5-5: 1;

(2) stirring the product obtained in the step (1) and heating to 50-70 ℃, then adding an end-capping agent, carrying out heat preservation reaction for 3-10 hours, and then carrying out evaporation concentration; the molar ratio of the product obtained in the step (1) to the end-capping reagent is 1: 5-10.

2. The preparation method of the nonionic aqueous epoxy resin curing agent according to claim 1, wherein the reaction temperature in the step (1) is 60-70 ℃ and the reaction time is 3-5 hours.

3. The preparation method of the nonionic aqueous epoxy resin curing agent according to claim 1, wherein the molar ratio of the ethylene glycol diglycidyl ether to the 3, 4-dimethoxyaniline in the step (1) is 2.5-3.5: 1.

4. The preparation method of the nonionic aqueous epoxy resin curing agent according to claim 1, wherein the reaction temperature in the step (2) is 55-65 ℃ and the reaction time is 4-6 h.

5. The preparation method of the nonionic aqueous epoxy resin curing agent according to claim 1, wherein the molar ratio of the product obtained in the step (1) to the end-capping agent in the step (2) is 1: 5-6.

6. The method for preparing the nonionic aqueous epoxy resin curing agent according to claim 1 or 5, wherein the end-capping agent is triethylene tetramine.

7. The method for preparing a nonionic aqueous epoxy resin curing agent according to claim 1, wherein the stirring speed in the step (2) is 15 r/s.

8. A non-ionic waterborne epoxy resin curing agent, which is characterized by being prepared by the method of any one of claims 1 to 7.

9. A water-based epoxy coating material, comprising the non-ionic water-based epoxy resin curing agent according to claim 7.

Technical Field

The invention belongs to the technical field of synthesis of epoxy resin curing agents, and particularly relates to a non-ionic waterborne epoxy resin curing agent and a preparation method thereof.

Background

The research and development directions of the epoxy resin curing agent are that a novel curing agent capable of improving humidity and heat resistance, toughening and strengthening, improving insulativity, improving flame retardant property, reducing viscosity and improving processability is researched, the use performance of the existing resin curing agent is improved through modification, and high efficiency and multiple functions of the curing agent are realized through a compounding technology. In recent years, environmental regulations for limiting Volatile Organic Compounds (VOC) are successively issued by many countries, the water-based coating becomes an important trend in the development of coatings, and the properties of the water-based epoxy curing agent used together with the coating have a crucial influence on the physical and chemical properties of the coating film. In foreign countries, many researches on waterborne epoxy curing agents are carried out, and some industrialized products exist, but the waterborne epoxy curing agents are expensive. In China, the research on the waterborne epoxy curing agent is less, and the waterborne epoxy curing agent is a mature product. Therefore, the development of a waterborne epoxy curing agent used in combination with a waterborne epoxy system having proprietary intellectual property rights has become a subject of intense research.

The waterborne epoxy curing agent is divided into two types, I type and ii type. For type I waterborne epoxy systems, the nonionic waterborne epoxy curing agent must be both a crosslinking agent and an emulsifier, so that the curing agent and the epoxy resin have good compatibility and good dispersibility in water. The first type I waterborne epoxy hardener that was developed successfully was Casmid 360 from Thomas Swan and its modified product Casmid 362. In the early days, amidated polyamine was used as curing agent for type I waterborne epoxy system, which can emulsify liquid epoxy resin, but the cured performance is not good, the water resistance and chemical resistance are poor, and the cured performance can be ensured to be close to solvent type epoxy resin coating by modifying the system. Because the pot life of an epoxy resin system emulsified by the polyamide curing agent is short, the cured coating film has the defects of poor flexibility, poor impact property and brittle coating film, and the performance of the modified polyamide curing agent is still not ideal, the curing agent for the I type waterborne epoxy system is mainly polyamine-epoxy adduct. The additive of TETA-NPER-032 is synthesized by the reaction of polyether glycol diglycidyl ether and triethylene tetramine, and then the additive reacts with liquid epoxy resin (EPON828) to synthesize the aqueous epoxy curing agent. Zhao Li Ying, Ma Hui Ru, etc. uses bisphenol A epoxy resin E44 and p-methoxy polyethylene glycol benzylamine as raw material to synthesize a new non-ionic self-emulsifying aqueous epoxy resin. Nivalin et al synthesizes a waterborne epoxy resin curing agent with both emulsification and curing functions by using propylene glycol methyl ether as a solvent and triethylene tetramine (TETA), epoxy resin and polyethylene glycol (PEG) as raw materials.

As for the II type waterborne epoxy curing agent, the epoxy resin in the system is prepared into emulsion in advance, and the epoxy resin does not need to be emulsified, so that the II type waterborne epoxy curing agent only needs to have the function of a cross-linking agent. The currently used type II waterborne epoxy curing agent is mainly an epoxy-amine curing agent prepared by the reaction of aliphatic amine or glycidyl ether embedded with hydrophilic polyoxyethylene chain segment and epoxy resin or polyethylene polyamine, or a polyamide curing agent prepared by the reaction of the aliphatic amine or glycidyl ether embedded with hydrophilic polyoxyethylene chain segment and dimer acid. For example, Ciba corporation has studied a new type II water-based epoxy hardener, the low activity hardener is a water-soluble epoxy-amine adduct, and the high activity hardener is a modified water-soluble epoxy-amine adduct, and the reactivity of the hardener is adjusted by the ratio of the two. It can produce O-VOC epoxy coatings without the need for coalescing solvents for the solid epoxy dispersion. While the conventional type II waterborne epoxy systems require the addition of coalescing solvents to lower the Tg of the resin to facilitate coalescence of the resin particles, which introduces volatile organic solvents, the new type II waterborne epoxy curatives solve this problem.

The water-based epoxy coating has the characteristics of good chemical resistance, adhesiveness, physical and mechanical properties and electrical insulation of a solvent-based epoxy coating, low pollution, simple and convenient construction, low price and the like. Since the development of the water-based epoxy coating technology abroad in the 7O era of the 2O century, the water-based epoxy coating is widely applied. The properties of the waterborne epoxy curing agent used together with a waterborne epoxy system have important influence on the physical and chemical properties of a coating film. Therefore, the development of the waterborne epoxy curing agent with independent intellectual property rights is of great significance to the coating industry in China.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a non-ionic waterborne epoxy resin curing agent and a preparation method thereof, and aims to provide a preparation method which is simple in process, safe and environment-friendly, mild in reaction condition and high in yield.

In order to achieve the purpose, the technical scheme adopted by the invention for solving the technical problems is as follows:

a preparation method of a nonionic waterborne epoxy resin curing agent comprises the following steps:

(1) heating the ethylene glycol diglycidyl ether solution to 60-90 ℃, then adding a 3, 4-dimethoxyaniline solution, carrying out heat preservation reaction for 3-10 h in a protective gas atmosphere, and carrying out evaporation concentration to obtain an ethylene glycol diglycidyl ether-3, 4-dimethoxyaniline addition product; the molar ratio of the ethylene glycol diglycidyl ether to the 3, 4-dimethoxyaniline is 1.5-5: 1;

(2) stirring the product obtained in the step (1) and heating to 50-70 ℃, then adding an end-capping agent, carrying out heat preservation reaction for 3-10 hours, and then carrying out evaporation concentration; the molar ratio of the product obtained in the step (1) to the end-capping reagent is 1: 5-10.

Further, the reaction temperature in the step (1) is 60-70 ℃, and the reaction time is 3-5 h.

Further, the molar ratio of the ethylene glycol diglycidyl ether to the 3, 4-dimethoxyaniline in the step (1) is 2.5-3.5: 1.

Further, the reaction temperature in the step (2) is 55-65 ℃, and the reaction time is 4-6 h.

Further, the molar ratio of the product obtained in the step (1) to the end-capping reagent in the step (2) is 1: 5-6.

Further, the end-capping reagent is triethylene tetramine.

Further, the stirring speed in the step (2) is 15 r/s.

A non-ionic waterborne epoxy resin curing agent is prepared by the method.

A water-based epoxy coating comprises the non-ionic water-based epoxy resin curing agent.

The invention has the beneficial effects that:

1. ethylene glycol diglycidyl ether and 3, 4-dimethoxyaniline are selected for preparing the non-ionic waterborne epoxy resin curing agent, a benzene ring structure is contained in the 3, 4-dimethoxyaniline, the structure of a product after curing and forming can be enhanced to a certain extent, and meanwhile, two methyl groups can enable a molecular chain to have flexibility, so that components containing the curing agent also have certain flexibility.

2. When the non-ionic waterborne epoxy resin curing agent is prepared, the ethylene glycol diglycidyl ether is properly excessive, so that the reaction speed can be accelerated, the complete reaction of the 3, 4-dimethoxyaniline can be ensured, and the cost can be reduced. If the amount of the ethylene glycol diglycidyl ether is too large, waste is caused, the cost is increased, and other byproducts are generated. Therefore, the nonionic waterborne epoxy resin curing agent with few byproducts and low preparation cost can be prepared by using the reaction dosage of the ethylene glycol diglycidyl ether and the 3, 4-dimethoxyaniline.

3. The ethylene glycol diglycidyl ether and the 3, 4-dimethoxyaniline can react at 60-90 ℃ and even lower 60-70 ℃, additives are not required to be added in the reaction process, the reaction conditions are mild, the product has higher yield, and the method is easy to realize. If the reaction is carried out at a lower temperature, the reaction speed is too slow, the reaction time is prolonged, and the yield of the product is reduced; if the reaction is carried out at a higher temperature, the amine groups on the benzene ring are easily oxidized, and the amount of by-products is increased, which also leads to a decrease in the yield of the product.

Drawings

FIG. 1 is an infrared spectrum of triethylene Tetramine (TEDA);

FIG. 2 is an infrared spectrum of ethylene glycol diglycidyl ether (SY-669) -3, 4-dimethoxyaniline-triethylene Tetramine (TEDA) (C-B-A-B-C type compound);

FIG. 3 is a mass spectrum of ethylene glycol diglycidyl ether (SY-669) -3, 4-dimethoxyaniline-triethylene Tetramine (TEDA) (compound type C-B-A-B-C);

FIG. 4 is a hydrogen spectrum of ethylene glycol diglycidyl ether (SY-669) -3, 4-dimethoxyaniline-triethylene Tetramine (TEDA) (compound type C-B-A-B-C);

FIG. 5 is a TG-DTG-DTA detection chart of ethylene glycol diglycidyl ether (SY-669) -3, 4-dimethoxyaniline-triethylene Tetramine (TEDA) (a compound of type C-B-A-B-C).

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.