阅读说明：本技术 一种离子型水性环氧改性固化剂及其制备方法 (Ionic waterborne epoxy modified curing agent and preparation method thereof ) 是由 何志威 倪青青 于 2020-07-22 设计创作，主要内容包括：本发明公开了一种离子型水性环氧改性固化剂及其制备方法,所述水性环氧固化剂的组分按质量百分比计为：硫脲7～12％、复配交联剂30～45％、缩水甘油醚18～24％、双酚A环氧树脂15～20％、小分子有机酸2～6％以及防霉剂0.3～0.8％,所述复配交联剂包括质量比为1.1～3.3/1的聚醚胺和脂肪族多胺。本发明所提供的水性环氧改性固化剂,能够有效提高涂料的防腐蚀性能和固化效率,同时也能提高涂料的综合性能及其稳定性。(The invention discloses an ionic waterborne epoxy modified curing agent and a preparation method thereof, wherein the waterborne epoxy modified curing agent comprises the following components in percentage by mass: 7-12% of thiourea, 30-45% of a compound crosslinking agent, 18-24% of glycidyl ether, 15-20% of bisphenol A epoxy resin, 2-6% of a small molecular organic acid and 0.3-0.8% of a mildew preventive, wherein the compound crosslinking agent comprises polyether amine and aliphatic polyamine in a mass ratio of 1.1-3.3/1. The waterborne epoxy modified curing agent provided by the invention can effectively improve the corrosion resistance and curing efficiency of the coating, and can also improve the comprehensive performance and stability of the coating.)

1. The ionic waterborne epoxy modified curing agent is characterized by comprising the following components in percentage by mass: 7-12% of thiourea, 30-45% of a compound crosslinking agent, 18-24% of glycidyl ether, 15-20% of bisphenol A epoxy resin, 2-6% of a small molecular organic acid and 0.3-0.8% of a mildew preventive, wherein the compound crosslinking agent comprises polyether amine and aliphatic polyamine in a mass ratio of 1.1-3.3/1.

2. The ionic waterborne epoxy modified curing agent of claim 1, wherein the aliphatic polyamine is ethylenediamine, diethylenetriamine, triethylenetetramine or tetraethylenepentamine.

3. The ionic waterborne epoxy modified curing agent of claim 1, wherein the molecular weight of the polyetheramine is 230 to 400.

4. The ionic waterborne epoxy modified curing agent according to claim 1, wherein the epoxy value of the bisphenol A epoxy resin is 0.4 to 0.55.

5. The ionic waterborne epoxy modified curing agent of claim 1, further comprising 4-8% of propylene glycol methyl ether and 2.5-5.7% of cyclohexanone.

6. The ionic waterborne epoxy modified curing agent of claim 1, wherein the glycidyl ether is phenyl glycidyl ether, benzyl glycidyl ether, butyl glycidyl ether, C12-14 alkyl glycidyl ether, polyethylene glycol diglycidyl ether, 1, 2-cyclohexanediol diglycidyl ether, or polypropylene glycol diglycidyl ether.

7. The ionic waterborne epoxy modified curing agent of claim 1, wherein the small organic acid is glacial acetic acid or formic acid.

8. The ionic waterborne epoxy modified curing agent of claim 1, wherein the mildew inhibitor is tetrachloroisophthalonitrile.

9. The preparation method of the ionic waterborne epoxy modified curing agent as claimed in any one of claims 1 to 8, characterized by comprising the following steps:

(1) under the condition of normal temperature stirring, heating 7-12% of thiourea according to mass percent to 60-85 ℃ for melting, then dropwise adding 30-45% of compound cross-linking agent, heating to 90-150 ℃, and reacting for 1-3 h;

(2) under the condition of stirring, continuously dropwise adding a mixed solution of 18-24% of glycidyl ether and 4-8% of propylene glycol methyl ether into the material obtained in the previous step, reacting at the constant temperature of 90-110 ℃ for 2-4 h, dropwise adding 15-20% of bisphenol A epoxy resin, and reacting at the constant temperature for 2-4 h;

(3) under the condition of stirring, adding 2-6% of small molecular organic acid into the material obtained in the previous step for neutralization, then adding 2.5-5.7% of cyclohexanone and 0.3-0.8% of mildew preventive, and stirring for 40-60 min to obtain a finished product.

Technical Field

The invention belongs to the field of water-based paint, and more particularly relates to an ionic water-based epoxy modified curing agent and a preparation method thereof.

Background

The water-based epoxy resin is widely used as a coating together with a curing agent. The general epoxy coating system is a film forming substance formed by water-based epoxy resin and a water-based epoxy curing agent, and the structural characteristics and the solvent content of the water-based epoxy curing agent play a key role in the film coating performance and the total Volatile Organic Compounds (VOC) of the coating.

The types of the existing epoxy resin curing agents are mainly divided into ionic type and nonionic type. The ionic curing agent is a waterborne system formed by neutralizing tertiary amine with organic acid in resin, and relevant data prove that the organic acid has negative effects on the color, the filler dispersion stability, the coating anti-corrosion performance and the flash rust inhibition of the curing agent; the nonionic curing agent is prepared by introducing nonionic polyether chain segments into the curing agent to enable the curing agent to be waterborne, but the viscosity of the curing agent is easily increased, more solvents are required to be diluted to reduce the viscosity, and a large amount of solvents can bring harm to the environment. Secondly, the simple preparation of the curing agent and its quick drying are still the focus of attention in the coating industry.

In summary, how to design an ionic waterborne epoxy modified curing agent can improve the corrosion resistance of a coating film, has stable comprehensive performance and quick drying property, and is a problem which needs to be solved at present.

Disclosure of Invention

The invention aims to solve the technical problems of poor corrosion resistance, unstable performance and poor quick drying property of the existing ionic waterborne epoxy curing agent, and provides an ionic waterborne epoxy modified curing agent and a preparation method thereof.

The invention realizes the aim through the following technical scheme, and provides an ionic waterborne epoxy modified curing agent which comprises the following components in percentage by mass: 7-12% of thiourea, 30-45% of a compound crosslinking agent, 18-24% of glycidyl ether, 15-20% of bisphenol A epoxy resin, 2-6% of a small molecular organic acid and 0.3-0.8% of a mildew preventive, wherein the compound crosslinking agent comprises polyether amine and aliphatic polyamine in a mass ratio of 1.1-3.3/1.

Further, the aliphatic polyamine is ethylenediamine, diethylenetriamine, triethylenetetramine or tetraethylenepentamine.

Further, the molecular weight of the polyether amine is 230-400.

The thiosemicarbazide obtained by reacting the compound crosslinking agent formed by matching polyether amine and aliphatic polyamine with thiourea can obviously improve the quick drying property of the coating.

Furthermore, the epoxy value of the bisphenol A epoxy resin is 0.4-0.55, and the bisphenol A epoxy resin in the epoxy value range is subjected to epoxy modification, so that the stability of a system can be kept, and the influence on a subsequent curing system is small.

Further, the material also comprises 4-8% of propylene glycol methyl ether and 2.5-5.7% of cyclohexanone.

Further, the glycidyl ether is phenyl glycidyl ether, benzyl glycidyl ether, butyl glycidyl ether, C12-14 alkyl glycidyl ether, polyethylene glycol diglycidyl ether, 1, 2-cyclohexanediol diglycidyl ether or polypropylene glycol diglycidyl ether.

Further, the small molecular organic acid is glacial acetic acid or formic acid.

Furthermore, the mildew preventive is tetrachloroisophthalonitrile, so that the antifouling and mildew-proof performance of the coating can be improved.

A preparation method of ionic waterborne epoxy modified curing agent comprises the following steps:

(1) under the condition of normal temperature stirring, heating 7-12% of thiourea according to mass percent to 60-85 ℃ for melting, then dropwise adding 30-45% of compound cross-linking agent, heating to 90-150 ℃, and reacting for 1-3 h;

(2) under the condition of stirring, continuously dropwise adding a mixed solution of 18-24% of glycidyl ether and 4-8% of propylene glycol methyl ether into the material obtained in the previous step, reacting at the constant temperature of 90-110 ℃ for 2-4 h, dropwise adding 15-20% of bisphenol A epoxy resin, and reacting at the constant temperature for 2-4 h;

(3) under the condition of stirring, adding 2-6% of small molecular organic acid into the material obtained in the previous step for neutralization, then adding 2.5-5.7% of cyclohexanone and 0.3-0.8% of mildew preventive, and stirring for 40-60 min to obtain a finished product.

The invention has the beneficial effects that:

(1) the ionic waterborne epoxy modified curing agent provided by the invention can effectively improve the corrosion resistance of the coating;

(2) according to the ionic waterborne epoxy modified curing agent provided by the invention, thiosemicarbazide obtained by reacting thiourea with aliphatic polyamine and polyether amine can greatly improve the fast drying property of the coating and improve the curing efficiency;

(3) the ionic waterborne epoxy modified curing agent provided by the invention can improve the comprehensive performance and stability of the coating through the matching of the raw materials;

(4) the modified curing agent is used, so that the raw material price is low and the modification cost is low.

Detailed Description

The technical solutions of the present invention will be described clearly and completely by the following specific embodiments, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.