CN116284805A - A kind of non-ionic water-based epoxy curing agent and its preparation method and application - Google Patents

Abstract

The invention belongs to the technical field of paint, and discloses a nonionic water-based epoxy curing agent, a preparation method and application thereof. The preparation method of the nonionic waterborne epoxy curing agent mainly comprises the following steps: reacting glycidyl ether with small molecular amine to obtain polyamine addition product; reacting epoxy resin, propylene glycol methyl ether and polyamine addition product to obtain epoxy-polyamine addition product; reacting the epoxy-polyamine adduct with monoepoxy glycidyl ether to obtain the nonionic aqueous epoxy hardener. The hydrophilicity of the finally formed curing agent is improved by introducing the flexible chain segment, the brittleness of a double-layer coating formed by the curing agent and the epoxy resin or the epoxy emulsion is solved, the amine-hydrogen ratio is effectively regulated, the subsequent film forming process is more stable, a formed paint film is more compact and uniform, and the acid-base resistance and the water resistance are improved; the obtained coating film has excellent mechanical property, water resistance and corrosion resistance.

Description

A kind of non-ionic water-based epoxy curing agent and its preparation method and application

technical field

The invention relates to the technical field of coatings, in particular to a nonionic water-based epoxy curing agent and a preparation method and application thereof.

Background technique

Epoxy resins are widely used in composite pads, adhesives, coatings, etc. because of their high mechanical properties, low cure shrinkage, excellent chemical resistance, and good processability. Compared with solvent-based epoxy resin systems, waterborne epoxy resin systems have the advantages of low VOC, reduced odor, reduced flammability and improved safety. Water-based epoxy curing agent is the key component that determines the performance of two-component ambient temperature curing water-based epoxy resin coating, and is the basis for water-based epoxy resin to enter the substantive application stage. Therefore, the preparation of water-based epoxy curing agent has been widely used in the industrial field. Widespread concern. Different from ionic curing agents, non-ionic curing agents introduce non-ionic hydrophilic segments into the curing agent, avoiding the introduction of organic acids into the curing agent to produce acetate, which makes the corrosion resistance and surface appearance of the cured film unfavorable Influence. At the same time, the non-ionic water-based epoxy curing agent can significantly solve the brittleness and corrosion resistance of the cured film, and has a mild synthesis process.

Therefore, providing a non-ionic water-based epoxy curing agent with simple preparation process and low energy consumption is of great significance for the wide application of water-based epoxy resins.

Contents of the invention

The object of the present invention is to provide a kind of non-ionic waterborne epoxy curing agent and its preparation method and application, to solve the problems existing in the prior art.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The invention provides a kind of preparation method of nonionic water-based epoxy curing agent, comprising the following steps:

(1) Chain extension reaction: mix glycidyl ether with small molecule amines, and react to obtain polyamine adducts;

(2) Addition reaction: mix epoxy resin, propylene glycol methyl ether and polyamine adducts, and react to obtain epoxy-polyamine adducts;

(3) Capping reaction: mix the epoxy-polyamine adduct with monoepoxy glycidyl ether, and react to obtain a nonionic water-based epoxy curing agent.

Preferably, in the preparation method of the above-mentioned a kind of non-ionic water-based epoxy curing agent, glycidyl ether is butyl glycidyl ether, phenyl glycidyl ether, polyethylene glycol diglycidyl ether in the step (1). One or more of ether, polypropylene glycol diglycidyl ether; the small molecule amine in the step (1) is N,N,N,N-tetrakis(3-aminopropyl)-1,4-ethylenediamine , N,N,N,N-Tetrakis(3-aminopropyl)-1,4-phenylenediamine, N,N-bis(3-aminopropyl)ethylenediamine, diethylenetriamine, triethylenetetra One or more of amine, tetraethylenepentamine, hexamethylenediamine, and propylenediamine.

Preferably, in the preparation method of above-mentioned a kind of nonionic waterborne epoxy curing agent, epoxy resin is epoxy resin E-20, epoxy resin E-44, epoxy resin E- One or more of 51.

Preferably, in the preparation method of the above-mentioned a kind of non-ionic water-based epoxy curing agent, the single epoxy glycidyl ether in the step (3) is phenyl glycidyl ether, butyl glycidyl ether, allyl glycidyl ether One or more of glyceryl ether, isopropyl glycidyl ether, o-cresyl glycidyl ether.

Preferably, in the preparation method of the above-mentioned non-ionic water-based epoxy curing agent, the mass ratio of the glycidyl ether, small molecular amine, epoxy resin, propylene glycol methyl ether, and monoepoxy glycidyl ether is 15～ 30:5～30:5～20:5～20:9～20.

Preferably, in the above-mentioned preparation method of a non-ionic water-based epoxy curing agent, the temperature of the reaction in the steps (1) to (3) is independently 50 to 80°C, and the steps (1) to ( The reaction time in 3) is independently 1-3 hours.

The present invention also provides a non-ionic water-based epoxy curing agent prepared by the above-mentioned preparation method of the non-ionic water-based epoxy curing agent.

The invention also provides the application of a non-ionic water-based epoxy curing agent in water-based coatings.

It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following beneficial effects:

1. The present invention introduces a polyether segment and a bisphenol A segment at the position of the primary amine in the small molecule amine, and adjusts the ratio of raw materials for synthesizing polyamine adducts to improve the hydrophilicity of the final curing agent with flexible segments. It solves the brittleness of the double-layer coating formed by the curing agent and epoxy resin or epoxy emulsion, and effectively adjusts the ratio of amine to hydrogen, making the subsequent film forming process more stable, and the formed paint film is denser and more uniform, acid and alkali resistant and water resistance have been improved.

2. The introduction of epoxy resin in the present invention makes the compatibility of curing agent and epoxy resin or epoxy emulsion stronger, and makes the compactness of curing agent and epoxy resin or epoxy emulsion to form a double-layer coating stronger, acid-resistant Improved performance, good water dilutability, and the obtained coating film has excellent mechanical properties, water resistance and corrosion resistance. At the same time, monoepoxy glycidyl ether is used as an end-capping agent to consume the remaining primary amine hydrogen, prolong the curing period of the curing agent and epoxy resin or epoxy emulsion, and facilitate on-site construction by workers.

3. The water-based epoxy curing agent prepared by the present invention has a mild production process and simple operation. The appearance of the curing agent is clear, transparent and light yellow, the storage stability is more than 6 months, and the active hydrogen equivalent is about 300g/eq.

Detailed ways

The invention provides a kind of preparation method of nonionic water-based epoxy curing agent, comprising the following steps:

(1) Chain extension reaction: mix glycidyl ether with small molecule amines, and react to obtain polyamine adducts;

(2) Addition reaction: mix epoxy resin, propylene glycol methyl ether and polyamine adducts, and react to obtain epoxy-polyamine adducts;

(3) Capping reaction: mix the epoxy-polyamine adduct with monoepoxy glycidyl ether, and react to obtain a nonionic water-based epoxy curing agent.

In the present invention, the specific method of mixing in the step (1) is: adding the glycidyl ether dropwise to the small molecular amine, and the dropping speed is 1d/s.

In the present invention, the glycidyl ether in the step (1) is preferably one or more of butyl glycidyl ether, phenyl glycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether species, more preferably one or more of butyl glycidyl ether, phenyl glycidyl ether, polyethylene glycol diglycidyl ether, more preferably phenyl glycidyl ether, polyethylene glycol diglycidyl ether one or both of them.

In the present invention, the small molecule amine in the step (1) is preferably N,N,N,N-tetrakis(3-aminopropyl)-1,4-ethylenediamine, N,N,N,N-tetrakis (3-aminopropyl)-1,4-phenylenediamine, N,N-bis(3-aminopropyl)ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine , one or more of propylenediamine, more preferably N,N,N,N-tetrakis(3-aminopropyl)-1,4-ethylenediamine, N,N-bis(3-aminopropyl one or more of ethylenediamine, triethylenetetramine, more preferably N,N-di(3-aminopropyl)ethylenediamine or triethylenetetramine.

In the present invention, the specific method of mixing in the step (2) is: first mix epoxy resin and propylene glycol methyl ether, then heat to obtain a co-solution of epoxy resin and propylene glycol methyl ether, and then add the co-solution dropwise to poly In the amine adduct, the dropping speed is 1d/s.

In the present invention, the epoxy resin in the step (2) is preferably one or more of epoxy resin E-20, epoxy resin E-44, epoxy resin E-51, more preferably epoxy resin One or both of resin E-20 and epoxy resin E-44, more preferably epoxy resin E-20.

In the present invention, after the reaction in the step (3), it further includes: adding water to adjust the solid content to 50 wt%, and cooling to 35°C.

In the present invention, the monoepoxy glycidyl ether in the step (3) is preferably phenyl glycidyl ether, butyl glycidyl ether, allyl glycidyl ether, isopropyl glycidyl ether, o-cresyl glycidyl ether One or more of glyceryl ethers, more preferably one or more of butyl glycidyl ether, allyl glycidyl ether, isopropyl glycidyl ether, o-cresyl glycidyl ether, more preferably One or both of allyl glycidyl ether and isopropyl glycidyl ether.

In the present invention, the mass ratio of glycidyl ether, small molecular amine, epoxy resin, propylene glycol methyl ether, and monoepoxy glycidyl ether is preferably 15-30:5-30:5-20:5-20: 9 to 20, more preferably 16 to 28:6 to 25:7 to 18:7 to 18:10 to 19, more preferably 20:11:10:10:15.

In the present invention, the reaction temperature in the steps (1) to (3) is independently preferably 50 to 80°C, more preferably 50, 54, 58, 60, 62, 65, 70, 73, 75, 78°C or 80°C, more preferably 58 or 60°C; the reaction time in the steps (1) to (3) is independently preferably 1 to 3 hours, more preferably 1, 1.25, 1.5, 1.75, 2, 2.25, 2.5 , 2.75 or 3h, more preferably 1.75, 2 or 2.25h.

The present invention also provides a non-ionic water-based epoxy curing agent prepared by the preparation method of the above-mentioned non-ionic water-based epoxy curing agent;

时，非离子型水性环氧固化剂的结构式为When the structural formula of the small molecule amine is

, the structural formula of the non-ionic water-based epoxy curing agent is

时，非离子型水性环氧固化剂的结构式为When the structural formula of the small molecule amine is

, the structural formula of the non-ionic water-based epoxy curing agent is

时，非离子型水性环氧固化剂的结构式为When the structural formula of the small molecule amine is

, the structural formula of the non-ionic water-based epoxy curing agent is

The present invention also provides a kind of application of nonionic water-based epoxy curing agent in water-based paint, and the method of described application in water-based paint is:

The non-ionic water-based epoxy curing agent is mixed with the water-based epoxy emulsion to obtain a two-component water-based epoxy varnish, and the mol ratio of the amine hydrogen in the non-ionic water-based epoxy curing agent to the epoxy group in the water-based epoxy emulsion is 1:1.25.

The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

A preparation method of nonionic water-based epoxy curing agent, comprising the following steps:

(1) Add 19.20 parts of polyethylene glycol diglycidyl ether dropwise to 11.50 parts of N,N-di(3-aminopropyl)ethylenediamine at a rate of 1d/s, at 60°C and 350r/min Insulation reaction for 3 hours to obtain polyamine adducts;

(2) Mix 11 parts of propylene glycol methyl ether with 11 parts of epoxy resin E-20, heat to obtain a co-solution of propylene glycol methyl ether and epoxy resin E-20, and then add the polyamine adduct dropwise at a speed of 1d/s , at 60°C and 350r/min for 2 hours, to obtain epoxy-polyamine adducts;

(3) Add 12.38 parts of phenylglycidyl ether into the epoxy-polyamine adduct, keep it warm for 2 hours at 60°C and 450r/min, and add 29.40 parts of deionized water after the reaction to adjust the solid content to 50wt%. Cool to 35°C and discharge to obtain a nonionic water-based epoxy curing agent.

Example 2

A preparation method of nonionic water-based epoxy curing agent, comprising the following steps:

(1) Add 26.20 parts of butyl glycidyl ether dropwise to 28.80 parts of N,N,N,N-tetrakis(3-aminopropyl)-1,4-ethylenediamine at a rate of 1d/s. ℃, 350r/min temperature insulation reaction for 3h, to obtain polyamine adducts;

(2) Mix 19.60 parts of propylene glycol methyl ether with 19.60 parts of epoxy resin E-51, heat to obtain a co-solution of propylene glycol methyl ether and epoxy resin E-51, and then add the polyamine adduct dropwise at a speed of 1d/s , at 60°C and 350r/min for 2 hours, to obtain epoxy-polyamine adducts;

(3) Add 18.20 parts of butyl glycidyl ether into the epoxy-polyamine adduct, and keep it warm for 2 hours at 60°C and 450r/min. After the reaction, add 35.20 parts of deionized water to adjust the solid content to 50wt%. Cool to 35°C and discharge to obtain a nonionic water-based epoxy curing agent.

Example 3

A preparation method of nonionic water-based epoxy curing agent, comprising the following steps:

(1) Add 20 parts of polypropylene glycol diglycidyl ether dropwise to 9.65 parts of triethylenetetramine at a rate of 1 d/s, and keep warm at 60°C and 350 r/min for 3 hours to obtain a polyamine adduct;

(2) Mix 5.45 parts of propylene glycol methyl ether with 5.45 parts of epoxy resin E-44, heat to obtain a co-solution of propylene glycol methyl ether and epoxy resin E-44, and then add the polyamine adduct dropwise at a speed of 1d/s , at 60°C and 350r/min for 2 hours, to obtain epoxy-polyamine adducts;

(3) 9.1 parts of butyl glycidyl ether are added to the epoxy-polyamine adduct, and the reaction is carried out at 60° C. and 450 r/min for 2 hours. After the reaction, 30.71 parts of deionized water are added to adjust the solid content to 50 wt%. Cool to 35°C and discharge to obtain a nonionic water-based epoxy curing agent.

Example 4

A preparation method of nonionic water-based epoxy curing agent, comprising the following steps:

(1) Add 20 parts of polypropylene glycol diglycidyl ether dropwise to 12.49 parts of tetraethylenepentamine at a rate of 1 d/s, and keep warm at 60°C and 350 r/min for 3 hours to obtain a polyamine adduct;

(2) Mix 5.45 parts of propylene glycol methyl ether with 5.45 parts of epoxy resin E-44, heat to obtain a co-solution of propylene glycol methyl ether and epoxy resin E-44, and then add the polyamine adduct dropwise at a speed of 1d/s , at 60°C and 350r/min for 2 hours, to obtain epoxy-polyamine adducts;

(3) Add 12.38 parts of phenylglycidyl ether into the epoxy-polyamine adduct, and keep the reaction for 2 hours at 60°C and 450r/min. After the reaction, add 35.72 parts of deionized water to adjust the solid content to 50wt%. Cool to 35°C and discharge to obtain a nonionic water-based epoxy curing agent.

Application example 1

The nonionic water-based epoxy curing agent prepared in Example 1 is mixed with the water-based epoxy emulsion to obtain a two-component water-based epoxy varnish, and then the two-component water-based epoxy varnish is formed into a film; the non-ionic water-based The molar ratio of the amine hydrogen in the epoxy curing agent to the epoxy group in the water-based epoxy emulsion is 1:1.25, and the epoxy equivalent of the water-based epoxy emulsion is 1066 g/mol.

Application example 2

Consistent with Application Example 1, the only difference is that the non-ionic water-based epoxy curing agent prepared in Example 2 is used.

Application example 3

Consistent with Application Example 1, the only difference is that the non-ionic water-based epoxy curing agent prepared in Example 3 is used.

Application example 4

Consistent with Application Example 1, the only difference is that the non-ionic water-based epoxy curing agent prepared in Example 4 is used.

Carry out performance tests on the coating films in application examples 1 to 4, and the tests are carried out according to the following standards:

Surface dry time: According to the requirements of the national standard GB/T 1728-2020, the surface dry time of various paint films is tested by the finger touch method;

Pencil hardness: Tested according to the national standard GB/T6739-2006 "Determination of paint film hardness by pencil method for paints and varnishes";

Adhesion: According to the requirements of the national standard GB/T 9286-2021, the adhesion of different paint films is rated by the method of manual grid drawing;

Water resistance: tested according to the national standard GB/T1733-93;

Acid resistance: Tested according to the requirements of the industry standard HG/T 5572-2019.

Alkali resistance: tested according to the requirements of the industry standard HG/T 5572-2019.

Testing environment conditions: temperature 25°C; humidity 50%RH.

The performance test results of the coating films in Application Examples 1-4 are shown in Table 1.

The performance test result of table 1 coating film

The manufacturer of the above-mentioned Banco903 is Liangu.

In summary, the water-based epoxy coating formed by the non-ionic water-based epoxy curing agent of the embodiment of the present invention has good water dilutability, and the obtained coating film has excellent mechanical properties, water resistance and corrosion resistance.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (8)

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

(1) Chain extension reaction: mixing glycidyl ether with small molecular amine, and reacting to obtain polyamine addition product;

(2) Addition reaction: mixing epoxy resin, propylene glycol methyl ether and polyamine adduct, and reacting to obtain epoxy-polyamine adduct;

(3) End-capping reaction: mixing the epoxy-polyamine adduct with monoepoxy glycidyl ether, and reacting to obtain the nonionic aqueous epoxy hardener.

2. The method for preparing the nonionic aqueous epoxy curing agent according to claim 1, wherein the glycidyl ether in the step (1) is one or more of butyl glycidyl ether, phenyl glycidyl ether, polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether; the small molecular amine in the step (1) is one or more of N, N, N, N-tetra (3-aminopropyl) -1, 4-ethylenediamine, N, N, N-tetra (3-aminopropyl) -1, 4-phenylenediamine, N, N-di (3-aminopropyl) ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine and propylenediamine.

3. The method for preparing a nonionic aqueous epoxy hardener of claim 2, wherein the epoxy resin in step (2) is one or more of epoxy resin E-20, epoxy resin E-44 and epoxy resin E-51.

4. The method for preparing a nonionic aqueous epoxy hardener of claim 2 or 3, wherein the monoepoxy glycidyl ether in the step (3) is one or more of phenyl glycidyl ether, butyl glycidyl ether, allyl glycidyl ether, isopropyl glycidyl ether and o-tolyl glycidyl ether.

5. The method for preparing the nonionic aqueous epoxy curing agent according to claim 2 or 3, wherein the mass ratio of the glycidyl ether to the small molecular amine to the epoxy resin to the propylene glycol methyl ether to the monoepoxy glycidyl ether is 15-30: 5-30: 5-20: 5-20: 9 to 20.

6. The method for producing a nonionic aqueous epoxy curing agent according to claim 5, wherein the reaction temperatures in the steps (1) to (3) are independently 50 to 80 ℃, and the reaction times in the steps (1) to (3) are independently 1 to 3 hours.

7. The nonionic aqueous epoxy hardener of any one of claims 1 to 6.

8. The use of the nonionic aqueous epoxy hardener of claim 7 in aqueous coatings.