阅读说明：本技术 一种水性双组份富锌专用环氧固化剂及其制备方法 (Water-based double-component zinc-rich special epoxy curing agent and preparation method thereof ) 是由 李辉宁 刘树飞 湛东东 董立志 于 2019-10-14 设计创作，主要内容包括：本发明公开了一种水性双组份富锌专用环氧固化剂及其制备方法,属于富锌底漆固化剂技术领域,包括以下步骤：(1)第一固化剂的制备：a.在催化条件下,将聚乙二醇与环氧树脂反应获得端环氧基聚合物；b.在氮气氛围中,将酸酐投入特殊胺组分中进行开环反应；c.向开环反应后的产物加入基础胺组分进行胺酯化反应获得酰胺聚合物；d.将所述端环氧基聚合物投入所述酰胺聚合物中,加入封端剂进行封端,即得第一固化剂；(2)第二固化剂的制备：在催化条件下,将油酸与基础胺脱水聚合成低分子量的聚酰胺,即得第二固化剂。本发明的固化剂,与水性环氧树脂配合,其生成的漆膜具有湿附着力好,耐盐雾性能优秀的特点,具有良好的应用前景。(The invention discloses a water-based double-component zinc-rich special epoxy curing agent and a preparation method thereof, belonging to the technical field of zinc-rich primer curing agents and comprising the following steps: (1) preparation of the first curing agent: a. under the catalysis condition, polyethylene glycol reacts with epoxy resin to obtain epoxy-terminated polymer; b. in the nitrogen atmosphere, adding anhydride into a special amine component for ring-opening reaction; c. adding a basic amine component into the product after the ring-opening reaction to carry out an amine esterification reaction to obtain an amide polymer; d. putting the epoxy-terminated polymer into the amide polymer, and adding a blocking agent for blocking to obtain a first curing agent; (2) preparation of the second curing agent: and (3) dehydrating and polymerizing the oleic acid and the basic amine into polyamide with low molecular weight under the catalytic condition to obtain the second curing agent. The curing agent disclosed by the invention is matched with the water-based epoxy resin, and a generated paint film has the characteristics of good wet adhesion and excellent salt spray resistance, and has a good application prospect.)

1. A preparation method of a water-based double-component zinc-rich special epoxy curing agent is characterized by comprising the following steps:

(1) preparation of the first curing agent:

a. under the catalysis condition, polyethylene glycol reacts with epoxy resin to obtain epoxy-terminated polymer;

b. in the nitrogen atmosphere, adding anhydride into a special amine component for ring-opening reaction;

c. adding a basic amine component into the product after the ring-opening reaction to carry out an amine esterification reaction to obtain an amide polymer;

d. putting the epoxy-terminated polymer into the amide polymer, and adding a blocking agent for blocking to obtain a first curing agent;

(2) preparation of the second curing agent:

and (3) dehydrating and polymerizing the oleic acid and the basic amine into polyamide with low molecular weight under the catalytic condition to obtain the second curing agent.

2. The preparation method of the aqueous two-component zinc-rich special epoxy hardener as claimed in claim 1, wherein in step a, the molar ratio of the polyethylene glycol to the epoxy resin is 1: 2-1: 4;

the polyethylene glycol is one or more of polyethylene glycol 400, polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 4000 and polyethylene glycol 8000;

the epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, polyethylene glycol glycidyl ether, polypropylene glycol glycidyl ether and polytetramethylene glycol glycidyl ether.

3. The preparation method of the aqueous two-component zinc-rich special epoxy curing agent according to claim 1, wherein in step b, the equivalent ratio of the acid anhydride to the primary amine in the special amine component is 1: 0.5-1: 1.

4. the preparation method of the aqueous two-component zinc-rich special epoxy hardener as claimed in claim 3, wherein the acid anhydride is one or more of tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride and methyl hexahydrophthalic anhydride; the special amine component is one or more of N-ethyl piperazine, polyether amine M-600, polyether amine M-1000, polyether amine M-2070, polyether amine D-400, polyether amine D-230, polyether amine EDR-148 and polyether amine T-403.

5. The preparation method of the aqueous two-component zinc-rich special epoxy hardener as claimed in claim 1, wherein in step c, the equivalent ratio of primary amine in the basic amine component to carboxyl group generated after ring opening is 1: 1-1: 4;

the basic amine component is: one or more of diethylenetriamine, triethylene tetramine, tetraethylene pentamine, isophorone diamine, m-xylylenediamine and hexamethylene diamine.

6. The preparation method of the aqueous two-component zinc-rich special epoxy curing agent according to claim 1, wherein in step d, the ratio of the blocking agent to the primary amine of the amide polymer is 1: 20-1: 3.

7. the preparation method of the aqueous two-component zinc-rich special epoxy curing agent as claimed in claim 6, wherein the blocking agent is one or more of butyl glycidyl ether, benzyl glycidyl ether, tertiary carboxylic acid glycidyl ether, octyl glycidyl ether and C9-C14 glycidyl ether.

8. The preparation method of the aqueous two-component zinc-rich special epoxy hardener as claimed in claim 1, wherein in the step (2), the molar ratio of the oleic acid to the basic amine is 1: 1-1: 1.1;

the oleic acid is eleostearic acid, linoleic acid, dehydrated ricinoleic acid or high-iodine oleic acid.

9. The preparation method of the aqueous two-component zinc-rich special epoxy hardener as claimed in claim 1, wherein the catalytic condition is that the catalyst is potassium persulfate, boron trifluoride or triphenylphosphine under the condition of adding the catalyst; the dosage of the catalyst is 1-4% of the solid portion.

10. The aqueous two-component zinc-rich special epoxy curing agent prepared by the preparation method of the aqueous two-component zinc-rich special epoxy curing agent according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of zinc-rich primer curing agents, in particular to a water-based two-component zinc-rich special epoxy curing agent and a preparation method thereof.

Background

In recent years, the national requirements for environmental protection are becoming more and more strict, and a series of regulatory policies are established particularly for the control of VOC emission, and the water-based paint is rapidly developed because the emission of organic solvents is greatly reduced and even completely eliminated, and the use is safe. The main resin structure is a key factor for achieving excellent product performance of the water-based paint. A large number of resin product categories currently emerging on the water-borne coating market include, for example: the application of the different resins greatly improves the physical properties of the waterborne coating in various aspects, so that the waterborne coating can be compared favorably with oily products. Among them, the aqueous epoxy resins are most widely used. Epoxy resin is widely used in various fields such as paint, adhesive, composite material and the like based on its characteristics of strong adhesion, good thermal stability, acid and alkali resistance, good insulativity, high mechanical strength and the like. Although the epoxy coating has excellent physical and chemical properties, the use of the conventional epoxy resin coating is harmful to the ecological environment and the health of people because the conventional epoxy resin coating is mostly solvent-based. In contrast, waterborne epoxy resins are increasingly receiving attention based on their environmental and health characteristics. The existing preparation method of the water-based epoxy resin mainly comprises an external emulsifier method and a self-emulsifying method. The external emulsification method is a method of utilizing an external surfactant to forcibly emulsify the epoxy resin under the action of high shear to obtain the aqueous epoxy resin emulsion. The product prepared by the method has large particle size and poor storage stability and water resistance. The self-emulsifying method is also called as chemical modification method, which utilizes the reactivity of epoxy resin active group to introduce hydrophilic group or chain segment to epoxy resin molecule, thus increasing the hydrophilic-lipophilic balance value and leading the epoxy resin molecule to be dispersed freely in water. In the self-emulsification method, the method can be further divided into: salt formation method and non-ionic modification method. The water-based epoxy resin emulsion prepared by the salt forming method has the defects of sensitivity to pH value, poor water resistance, poor anticorrosion effect and the like. The nonionic modification method is to introduce a hydrophilic polyoxyethylene segment into the molecular skeleton of an epoxy resin by an appropriate method to obtain a modified epoxy resin containing a hydrophilic segment, and then to self-disperse the modified epoxy resin in water. The nonionic modification method does not need an additional emulsifier, and the prepared water-based epoxy resin emulsion has good stability, small particle size and excellent comprehensive performance of a coating film, so that the water-based epoxy resin emulsion is suitable for practical application. For the above nonionic modification method, prior document US4315044 discloses a method of forming a nonionic self-emulsifying aqueous epoxy resin by introducing a polyoxyethylene segment into the main chain of the epoxy resin. In addition, chinese patent CN101260183 discloses a diepoxy end group intermediate prepared from polyether alcohol and low molecular weight epoxy resin, bisphenol a and low molecular weight epoxy resin, and a technical scheme of introducing a nonionic polyether segment into the main chain of the epoxy resin by a "two-step method" to obtain the nonionic self-emulsifying waterborne epoxy resin. In the technical scheme disclosed above, long polyether chains are introduced into the main chain of the prepared water-dispersible epoxy resin, so that the cross-linking density of the cured epoxy resin is low, the coating film strength is low, and the corrosion resistance is poor. However, in the aqueous epoxy resin coating material, the aqueous epoxy curing agent is also an indispensable part thereof. The existing preparation method of the water-based epoxy curing agent is to modify common amines to enhance the hydrophilicity. The most common preparation methods are: the amine-epoxy compound is prepared by the reaction of an epoxy compound and amine, and then a hydrophilic molecular chain is introduced or micromolecular organic acid is added for neutralization to form salt, so that the prepared curing agent has certain hydrophilicity. For example, U.S. Pat. No. 5,53691,691 discloses a process for preparing a water-soluble epoxy hardener by chain extending an epoxy with an isocyanate, then partially blocking the epoxy with a mixture of a small organic acid and a tertiary amine, and finally adding a conventional amine to obtain a water-soluble epoxy hardener. Chinese patent CN 101649041A discloses a preparation method of a self-emulsifying water-based epoxy resin curing agent, wherein an amine-epoxy adduct is prepared firstly, then a mixed end-capping agent is added for end capping, and finally organic acid is added for neutralization and salt formation. In the existing preparation methods, the hydrophilicity is improved by using a mode of neutralizing organic acid into salt, but after the organic acid component is added, a paint film is easy to generate flash corrosion on metal, and the water resistance and salt spray resistance of the paint film are reduced.

In summary, the waterborne epoxy curing agents in the prior art have the following disadvantages: the compatibility with the waterborne epoxy zinc-rich special resin is poor; the hydrophilicity is improved by using a mode of neutralizing organic acid into salt, but after the organic acid component is added, a paint film is easy to generate flash erosion on metal, and the water resistance and salt spray resistance of the paint film can be reduced; most curing agents currently used have slightly poor salt fogging and mechanical properties. Therefore, the development of a curing agent specially aiming at the water-based epoxy zinc-rich coating is needed.

Disclosure of Invention

The invention aims to provide a water-based two-component zinc-rich special epoxy curing agent and a preparation method thereof, which are used for solving the problems in the prior art.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a preparation method of a water-based two-component zinc-rich special epoxy curing agent, which comprises the following steps:

(1) preparation of the first curing agent:

a. under the catalysis condition, polyethylene glycol reacts with epoxy resin to obtain epoxy-terminated polymer;

b. in the nitrogen atmosphere, adding anhydride into a special amine component for ring-opening reaction;

c. adding a basic amine component into the product after the ring-opening reaction to carry out an amine esterification reaction to obtain an amide polymer;

d. putting the epoxy-terminated polymer into the amide polymer, and adding a blocking agent for blocking to obtain a first curing agent;

(2) preparation of the second curing agent:

and (3) dehydrating and polymerizing the oleic acid and the basic amine into polyamide with low molecular weight under the catalytic condition to obtain the second curing agent.

Further, in the step a, the molar ratio of the polyethylene glycol to the epoxy resin is 1: 2-1: 4;

the polyethylene glycol is one or more of polyethylene glycol 400, polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 4000 and polyethylene glycol 8000;

the epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, polyethylene glycol glycidyl ether, polypropylene glycol glycidyl ether and polytetramethylene glycol glycidyl ether.

Further, in step b, the equivalent ratio of the acid anhydride to the primary amine in the particular amine component is 1: 0.5-1: 1.

further, the acid anhydride is one or more of tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride and methyl hexahydrophthalic anhydride; the special amine component is one or more of N-ethyl piperazine, polyether amine M-600, polyether amine M-1000, polyether amine M-2070, polyether amine D-400, polyether amine D-230, polyether amine EDR-148 and polyether amine T-403.

Further, in step c, the equivalent ratio of the primary amine in the base amine component to the carboxyl group generated after ring opening is 1: 1-1: 4;

the basic amine component is: one or more of diethylenetriamine, triethylene tetramine, tetraethylene pentamine, isophorone diamine, m-xylylenediamine and hexamethylene diamine.

Further, in step d, the ratio of the blocking agent to the primary amine of the amide polymer is 1: 20-1: 3.

further, the end-capping agent is one or more of butyl glycidyl ether, benzyl glycidyl ether, tertiary carbonic acid glycidyl ether, octyl glycidyl ether and C9-C14 glycidyl ether.

Further, in the step (2), the molar ratio of the oleic acid to the basic amine is 1: 1-1: 1.1;

the oleic acid is eleostearic acid, linoleic acid, dehydrated ricinoleic acid or high-iodine oleic acid.

Further, the catalytic condition means that under the condition of adding a catalyst, the catalyst is potassium persulfate, boron trifluoride or triphenylphosphine; the dosage of the catalyst is 1-4% of the solid part, and the solid part refers to the non-volatile content of the designed curing agent.

The invention also provides the aqueous two-component zinc-rich special epoxy curing agent prepared by the preparation method.

The invention discloses the following technical effects:

according to the water-based two-component zinc-rich special epoxy curing agent provided by the invention, the epoxy-terminated polymer and the amide polymer are respectively generated and finally react to obtain the water-based two-component zinc-rich special epoxy curing agent, no organic acid raw material is introduced, the prepared finished product has the advantage of low viscosity, and the zinc-rich primer prepared by matching with the water-based epoxy resin has the characteristics of good wet adhesion and excellent salt mist resistance, so that the water-based two-component zinc-rich special epoxy curing agent has a good application prospect.

According to the water-based double-component zinc-rich special epoxy curing agent, the nonionic polyether chain segment is introduced into the first curing agent, the particle size formed by water-soluble self-emulsification is small, the polyether amine and the m-phenylenediamine are introduced to improve the protection capability on a base material and the compatibility on water-based resin, and the low-molecular amine is introduced into the second curing agent to synthesize polyamide, so that good flexibility and reaction rate can be provided.

The reaction mechanism of the aqueous two-component zinc-rich special epoxy curing agent is as follows: hydroxyl in the polyether and epoxy in the epoxy resin are etherified under the high-temperature condition of a catalyst to introduce the polyether to form an intermediate, and the introduction of the polyether realizes self-emulsification. Different monomer amine primary amine groups are combined to react with anhydride groups in anhydride to form amide, active hydrogen is introduced, and the amide reacts with epoxy groups in a polyether intermediate to introduce polyether chain segments of hydrophilic groups, so that self-emulsification is realized.

The action principle of the aqueous two-component zinc-rich special epoxy curing agent and the zinc-rich primer is as follows: the polyether in the curing agent self-emulsifies the epoxy resin in the zinc-rich primer in the water phase to form a stable dispersion, and then the active hydrogen in the curing agent and the epoxy resin are subjected to a cross-linking reaction to form a paint film.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The specification and examples are exemplary only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

The "parts" in the present invention are all parts by mass unless otherwise specified.