CN112430287B

CN112430287B - Cationic acrylate emulsion, preparation method and application thereof

Info

Publication number: CN112430287B
Application number: CN202011343786.9A
Authority: CN
Inventors: 陈均; 叶小乐
Original assignee: Anhui University of Technology AHUT
Current assignee: Anhui University of Technology AHUT
Priority date: 2020-11-25
Filing date: 2020-11-25
Publication date: 2023-01-03
Anticipated expiration: 2040-11-25
Also published as: CN112430287A

Abstract

The invention discloses a cationic acrylate emulsion, a preparation method and application thereof, wherein the cationic acrylate emulsion comprises, by weight, 40% of a functional monomer aqueous solution, 0-2% of a self-crosslinking monomer, 35% of an acrylate monomer, 0.1-0.5% of an emulsifier, 0.2% of an initiator and the balance of water, wherein the total mass of the cationic acrylate emulsion is calculated in percentage. The self-crosslinking cationic acrylate emulsion adopts polymerizable polyhydroxy organic amine as a functional monomer, so that the successful implementation of emulsion polymerization and the stability of emulsion particles are ensured, positive charges and a large number of hydroxyl and amino groups are provided for the surfaces of the emulsion particles, the surface of an aluminum alloy substrate is endowed with excellent adhesive force of a resin passivation film, and the corrosion resistance of the passivation film is improved.

Description

Cationic acrylate emulsion, preparation method and application thereof

Technical Field

The invention belongs to the field of surface treatment of aluminum alloy materials, and particularly relates to a cationic acrylate emulsion, a preparation method and application thereof.

Background

Aluminum alloys are considered desirable materials in many respects due to a combination of excellent mechanical properties and excellent strength to weight ratio. However, the uneven distribution of particles between metals in the aluminum alloy may induce different electrochemical characteristics and accelerate local corrosion of the aluminum alloy. Generally, a thin layer of aluminum oxide naturally formed on the surface of the substrate can improve corrosion resistance, but the thickness of such an oxide film is only in the nanometer scale, and the protection of the substrate is limited. At first, people adopt chromate passivation, the passivation effect is good, but hexavalent chromium belongs to a toxic substance carcinogen, the toxic substance carcinogen has great harm to human bodies and the environment, and people look to environment-friendly organic chromium-free passivation.

At present, extensive research on chromium-free passivation technology has been carried out at home and abroad. Common chromium-free passivation solutions can be roughly classified into inorganic passivation, organic passivation and inorganic/organic composite passivation types according to their components. The passivation of the organic resin mainly means that the organic resin is polymerized and crosslinked on the metal surface to improve the compactness of a film layer so as to reduce the corrosion rate of the metal. The acrylic resin has excellent weather resistance, water resistance and gloss resistance, and is widely applied to general industrial equipment, leather, paper industry and the like. However, because no crosslinking occurs between polyacrylate macromolecular chains, many defects exist after film formation, such as uneven film formation, film layer fracture, poor corrosion resistance of the film layer and the like, researchers introduce reactive functional groups into polymer molecular chains, and the polymer molecular chains can be crosslinked and cured through the reaction between the functional groups to form a three-dimensional network structure, so that the self-crosslinking acrylic emulsion is obtained, the cohesive force of the polymer is obviously improved, and the excellent performance of the acrylic emulsion is fully exerted. The functional groups of the crosslinking monomer mainly comprise hydroxyl, epoxy, amide and the like, and can simultaneously perform chemical reaction with the soft and hard monomers and the carboxyl monomers to form crosslinking macromolecules with a network structure.

Most of the researches on acrylate emulsion polymerization at home and abroad mainly take anionic acrylate emulsion, but the researches and reports on cationic acrylate resin emulsion are less. However, the cationic acrylate resin emulsion has positive charges, so that the cationic acrylate resin emulsion has functions which cannot be replaced by other ionic acrylate resin emulsions in many aspects. In addition, most of the acrylic emulsions used in the market at present are nonionic emulsions and anionic emulsions, and most of the emulsions have poor stability. The cationic acrylate polymer emulsion is characterized in that the surface of latex particles or the polymer is positively charged, a cationic emulsifier is usually adopted to positively charge the surface of the latex particles, and an active monomer containing a cationic group is required to participate in copolymerization to endow the acrylate polymer with positive charge and prepare an ideal polymer emulsion.

Disclosure of Invention

This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and title of the application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.

The present invention has been made keeping in mind the above and/or other problems occurring in the prior art.

Accordingly, it is an object of the present invention to overcome the deficiencies of the prior art and to provide a cationic acrylate emulsion.

In order to solve the technical problems, the invention provides the following technical scheme: a cationic acrylate emulsion comprises a functional monomer aqueous solution, a self-crosslinking monomer, an acrylate monomer, an emulsifier, an initiator and water; wherein, by taking the total mass of the cationic acrylate emulsion as a hundred percent, the content of the functional monomer aqueous solution is 40 percent, the content of the self-crosslinking monomer is 0 to 2 percent, the content of the acrylate monomer is 35 percent, the content of the emulsifier is 0.1 to 0.5 percent, the content of the initiator is 0.2 percent, and the balance is water; the functional monomer aqueous solution is a polymerizable polyhydroxy organic amine functional monomer, and the preparation method comprises the following steps: placing glycidyl methacrylate in an ice water bath, dropwise adding diethanolamine while stirring, continuously stirring for reaction after dropwise adding is finished to obtain a polymerizable polyhydroxy organic amine functional monomer, dissolving the polymerizable polyhydroxy organic amine functional monomer in water, and adjusting the pH value to 5-6 to obtain a functional monomer aqueous solution; the molar ratio of the glycidyl methacrylate to the diethanolamine is 1:1, the mass concentration of the functional monomer in the functional monomer aqueous solution is 2-10%; wherein the self-crosslinking monomer is N-hydroxyethyl acrylamide; wherein the acrylic monomer is a mixture of two or more of methyl methacrylate, butyl acrylate, acrylic acid and methyl acrylate; the emulsifier is cetyl trimethyl ammonium bromide; the initiator is azodiisobutyramidine hydrochloride.

As a preferable embodiment of the cationic acrylate emulsion of the present invention, wherein: the cationic acrylate emulsion comprises, by mass percentage, 40% of the functional monomer aqueous solution, 0.8% of the self-crosslinking monomer, 35% of the acrylate monomer, 0.41% of the emulsifier, 0.2% of the initiator and the balance of water; the mass concentration of the functional monomer in the functional monomer aqueous solution was 4%.

As a preferable embodiment of the cationic acrylate emulsion of the present invention, wherein: and continuously stirring for reaction to obtain the polymerizable polyhydroxy organic amine functional monomer, wherein the continuous stirring reaction time is 3-4 h.

As a preferable embodiment of the cationic acrylate emulsion of the present invention, wherein: the polymerizable polyhydroxy organic amine functional monomer is dissolved in water, and the pH is adjusted to 5-6, wherein the pH is adjusted by acetic acid or phosphoric acid.

It is a further object of the present invention to overcome the deficiencies of the prior art and to provide a method for preparing a cationic acrylate emulsion.

In order to solve the technical problems, the invention provides the following technical scheme: a preparation method of cationic acrylate emulsion comprises dissolving initiator in a certain amount of water to obtain initiator aqueous solution; dissolving a self-crosslinking monomer in a functional monomer aqueous solution to obtain a functional monomer mixed aqueous solution; uniformly mixing acrylate monomers to obtain an acrylate monomer mixed solution; putting the emulsifier and the rest water into a reaction kettle, stirring and dissolving, adding 30% of the functional monomer mixed aqueous solution and 10% of the acrylate monomer mixed aqueous solution, stirring and heating to 72 ℃, and adding 30% of the initiator aqueous solution; after reacting for 15min, simultaneously dripping the rest of the initiator aqueous solution, the functional monomer mixed aqueous solution and the acrylate monomer mixed solution into a polymerization system for 2.5-3 h; reacting for 15min, heating to 82 ℃, reacting for 90min at constant temperature, naturally cooling and filtering to obtain self-crosslinking cationic acrylic acid cationic emulsion; wherein, by taking the total mass of the cationic acrylate emulsion as a hundred percent, the content of the functional monomer aqueous solution is 40 percent, the content of the self-crosslinking monomer is 0 to 2 percent, the content of the acrylate monomer is 35 percent, the content of the emulsifier is 0.1 to 0.5 percent, the content of the initiator is 0.2 percent, and the balance is water; the method comprises the following steps of dissolving an initiator in a certain amount of water to obtain an initiator aqueous solution, wherein the water addition amount is 4 percent based on the total mass of the cationic acrylate emulsion.

As a preferable scheme of the preparation method of the cationic acrylate emulsion, the method comprises the following steps: the self-crosslinking monomer is N-hydroxyethyl acrylamide; the acrylic monomer is a mixture of two or more of methyl methacrylate, butyl acrylate, acrylic acid and methyl acrylate; the emulsifier is cetyl trimethyl ammonium bromide; the initiator is azodiisobutyramidine hydrochloride.

As a preferable embodiment of the method for preparing the cationic acrylate emulsion of the present invention, wherein: the functional monomer aqueous solution is polymerizable polyhydroxy organic amine functional monomer, and the preparation method comprises the steps of putting glycidyl methacrylate into an ice water bath, dropwise adding diethanolamine while stirring, continuously stirring for reaction after dropwise adding is finished to obtain polymerizable polyhydroxy organic amine functional monomer, dissolving the polymerizable polyhydroxy organic amine functional monomer in water, and adjusting the pH value to 5-6 to obtain the functional monomer aqueous solution; the molar ratio of the glycidyl methacrylate to the diethanolamine is 1:1, the mass concentration of the functional monomer in the functional monomer aqueous solution is 2-10%.

The invention also aims to overcome the defects in the prior art and provide the application of the cationic acrylate emulsion in the resin passivation solution for the surface of the aluminum alloy.

In order to solve the technical problems, the invention provides the following technical scheme: the application of the cationic acrylate emulsion in the resin passivation solution on the surface of the aluminum alloy comprises the cationic acrylate emulsion and water, wherein the content of the cationic acrylate emulsion is 10% and the balance is water, based on the total mass of the resin passivation solution in percentage by weight.

As a preferable embodiment of the application of the cationic acrylate emulsion of the present invention, wherein: the resin passivation solution on the surface of the aluminum alloy comprises a cationic acrylate emulsion, phytic acid and water, wherein the cationic acrylate emulsion accounts for 10 percent, the phytic acid accounts for 1.0 percent and the balance is water by taking the total mass of the resin passivation solution as a hundred percent.

The invention has the beneficial effects that:

(1) The resin passivation solution prepared by adopting the self-crosslinking cationic acrylate emulsion as the main film forming substance fundamentally removes the harm of hexavalent chromium and trivalent chromium elements in the traditional passivation solution to the environment and human body, and is a novel environment-friendly chromium-free resin passivation solution. The self-crosslinking cationic acrylate emulsion adopts polymerizable polyhydroxy organic amine as a functional monomer, so that the successful implementation of emulsion polymerization and the stability of emulsion particles are ensured, positive charges and a large number of hydroxyl and amino groups are provided for the surfaces of the emulsion particles, the surface of an aluminum alloy substrate is endowed with excellent adhesive force of a resin passivation film, and the corrosion resistance of the passivation film is improved.

(2) The self-crosslinking cationic acrylate emulsion adopts N-hydroxyethyl acrylamide as a crosslinking monomer, realizes the self-crosslinking performance of the cationic acrylate emulsion, enables the resin passivation film to form a compact crosslinking net structure, endows the resin passivation film with excellent barrier performance to corrosion factors (oxygen, water and the like), and improves the corrosion resistance of the resin passivation film.

(3) The polyhydroxy and amino groups on the surface of the self-crosslinking cationic acrylate emulsion particle endow the emulsion with excellent compatibility, the emulsion has good balance performance on positive and negative charges, the prepared cationic acrylate emulsion/phytic acid composite resin passivation solution has good stability, and the synergistic effect of the cationic acrylic emulsion and the anionic phytic acid corrosion inhibitor endows the resin passivation film with excellent corrosion resistance. The passivation process and equipment of the resin passivation solution are equivalent to those of the traditional passivation process and equipment, and the existing equipment is not required to be modified. The passivation process is simple and reliable, and the aluminum alloy plate treated by the passivation solution has excellent corrosion resistance.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive labor. Wherein:

FIG. 1 is a graph of the glass transition temperature test results of self-crosslinking cationic acrylate latex films with different N-hydroxyethyl acrylamide contents in the examples of the present invention; wherein, the content of N-hydroxyethyl acrylamide is as follows: a-e correspond to 0, 0.4, 0.8, 1.2, 1.6%, respectively.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, specific embodiments thereof are described in detail below with reference to examples of the specification.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

The raw materials in the present invention are all industrial grade common commercial raw materials without specific description.

Example 1

(1) A cationic acrylate emulsion comprising:

functional monomer aqueous solution, self-crosslinking monomer, acrylate monomer, emulsifier, initiator and water;

wherein, by taking the total mass of the cationic acrylate emulsion as hundred percent, the content of the functional monomer aqueous solution is 40 percent, the content of the acrylate monomer is 35 percent, the content of the emulsifier is 0.41 percent, the content of the initiator is 0.2 percent, and the balance is water;

the functional monomer aqueous solution is a polymerizable polyhydroxy organic amine functional monomer, and the preparation method comprises the following steps: placing glycidyl methacrylate in an ice water bath, dropwise adding diethanolamine while stirring, continuously stirring for reacting for 3 hours after dropwise adding is finished to obtain a polymerizable polyhydroxy organic amine functional monomer, dissolving the polymerizable polyhydroxy organic amine functional monomer in water, and adjusting the pH value to 6 with acetic acid to obtain a functional monomer aqueous solution; the molar ratio of the glycidyl methacrylate to the diethanolamine is 1:1, the mass concentrations of the functional monomers in the functional monomer aqueous solution are respectively 0%,2%,4%,6%,8%,10% and 12.5%;

wherein the acrylic monomer is a mixture consisting of methyl methacrylate and butyl acrylate according to a mass ratio of 1.5; the emulsifier is cetyl trimethyl ammonium bromide; the initiator is azodiisobutyramidine hydrochloride.

(2) The preparation method of the cationic acrylate emulsion comprises the following steps:

dissolving an initiator in a certain amount of water to obtain an initiator aqueous solution, wherein the water addition amount is 4 percent based on the total mass percent of the cationic acrylate emulsion;

uniformly mixing acrylate monomers to obtain an acrylate monomer mixed solution (the adopted acrylate monomers are all liquid at normal temperature);

putting the emulsifier and the rest water into a reaction kettle, stirring and dissolving, adding 30% of the functional monomer aqueous solution and 10% of the acrylate monomer mixed solution, stirring and heating to 72 ℃, and adding 30% of the initiator aqueous solution; wherein, adding 30% of the functional monomer solution means that 30% of the functional monomer solution is added, and the rest 70% is remained to be dripped in the next step, while the functional monomer solution accounts for 40% in the whole system formula, and the addition of the acrylate monomer mixed solution and the initiator aqueous solution is also the same;

after reacting for 15min, simultaneously dropwise adding the residual initiator aqueous solution, the functional monomer aqueous solution and the acrylate monomer mixed solution into a polymerization system for 2.5-3 h;

reacting for 15min, heating to 82 ℃, reacting for 90min at constant temperature, naturally cooling and filtering to obtain the self-crosslinking cationic acrylic acid cationic emulsion.

The polymerization results are shown in Table 1 below.

TABLE 1

It can be seen that when the polymerizable polyhydroxy organic amine functional monomer is not used, a large amount of slag is generated in the polymerization process, the reaction cannot be carried out, and the cationic acrylate emulsion cannot be obtained, which indicates that the use of the polymerizable polyhydroxy organic amine functional monomer in the invention can ensure the successful implementation of emulsion polymerization and the stability of latex particles, and when the content of the functional monomer is 1.6-4%, the cationic acrylate emulsion with smaller particle size is obtained. When the content of the functional monomer is more than 4%, the emulsion polymerization easily causes gelation.

Example 2

Based on example 1, the fixed functional monomer content was 4%, and the emulsifier contents were varied to 0%,0.17%,0.26%,0.34% and 0.41%, respectively, and the polymerization results are shown in table 2 below.

TABLE 2

It can be seen that when cetyl trimethylammonium bromide was not used as an emulsifier, the reaction gelled severely and a cationic acrylate emulsion could not be obtained. When a small amount of emulsifier is added, the cationic acrylate emulsion can be successfully obtained, and considering the influence of the emulsifier on the water resistance of the passive film, when the content of the emulsifier is 0.26-0.41%, the obtained emulsion has smaller grain size and better water resistance of the emulsion film, and is more suitable for resin passivation treatment of the surface of the aluminum alloy.

Example 3

The content of the fixed functional monomer is 4 percent, the content of the emulsifier is 0.41 percent, and the content of the self-crosslinking monomer N-hydroxyethyl acrylamide is respectively changed to be 0.4 percent, 0.8 percent, 1.2 percent and 1.6 percent. Based on example 1, self-crosslinking monomer N-hydroxyethyl acrylamide is dissolved in the functional monomer aqueous solution, and the rest of the polymerization process is the same. The polymerization results are shown in Table 3 below.

TABLE 3

As can be seen from Table 3, the use of the self-crosslinking monomer N-hydroxyethyl acrylamide does not affect the smooth implementation of emulsion polymerization, and the self-crosslinking cationic acrylate emulsion is successfully obtained. The glass transition temperature test results of the self-crosslinking cationic acrylate emulsion films obtained by different N-hydroxyethyl acrylamide contents show that the glass transition temperature of the cationic acrylate emulsion is obviously improved by using the N-hydroxyethyl acrylamide as shown in figure 1, and the self-crosslinking performance of the cationic acrylate emulsion is realized.

Example 4

On the basis of example 3, 20g of self-crosslinking cationic acrylate emulsion is added with deionized water to prepare 200g of passivation solution.

And (3) grinding the aluminum oxide film on the surface of the ADC12 aluminum alloy plate by using No. 240, no. 600 and No. 1000 abrasive paper, and ultrasonically washing by using deionized water. Then preparing 10g/L aqueous solution of 50 ℃ alkaline degreasing agent, and putting and cleaning the aluminum alloy plate for 5min. And repeatedly washing the aluminum plate with deionized water after being taken out, then immersing the aluminum plate in the passivation solution for 90s, taking out the aluminum plate, hovering the aluminum plate in the air for 3s, then placing the aluminum plate into an electric blowing drying oven at 100 ℃, and drying the aluminum plate for 30min to form a film.

The properties of the passivated aluminum alloy sheet film layer are shown in table 4 below.

TABLE 4

A blank aluminum alloy sheet was subjected to the same pretreatment as a control. The results in table 4 show that the self-crosslinking cationic acrylate emulsion of the invention adopts N-hydroxyethyl acrylamide as a crosslinking monomer, thereby realizing the self-crosslinking performance of the cationic acrylate emulsion, forming a dense crosslinked network structure on the resin passivation film, endowing the resin passivation film with excellent barrier performance against corrosion factors (oxygen, water and the like), and improving the corrosion resistance of the resin passivation film. The content of the N-hydroxyethyl acrylamide is 0.8%, the performance of the resin passive film is optimal, and when the content is less than 0.8%, the corrosion resistance of the resin passive film is poor due to insufficient crosslinking density; when the content is higher than 0.8%, more hydrophilic groups are introduced, so that the water resistance of the film layer is reduced, and the corrosion resistance of the film layer is reduced because a corrosive medium permeates into the film layer.

Electrochemical test a 3.5% sodium chloride aqueous solution was used to simulate a natural corrosive environment and tested by a CHI660E electrochemical workstation.

(1) AC impedance spectroscopy (EIS)

According to the Open Circuit Potential-Time method, the scanning Time is 1800s, the scanning Potential range is-1V, and the stable Open Circuit Potential value Ee is read out. Setting the scanning potential as Ee, the experimental parameter scanning amplitude as 0.005V and the frequency as 0.01-10 according to the AC impedance method (A.C. impedance) ⁵ Hz, standing for 2s, and measuring a phase angle and an impedance modulus.

(2) Tafel polarization curve (Tafel)

According to an Open Circuit Potential-Time method, the scanning Time is 40s, the scanning Potential range is-1 to 1V, and an Open Circuit Potential value Ee is read. Setting according to Tafel line extrapolation method (Tafel), wherein the scanning potential range is Ee +/-0.25, the experimental parameter scanning rate is 0.001V/s, the standing time is 2s, and the sensitivity is 10 ^-3 And (5) A/V. And calculating the corrosion potential and the corrosion current density according to the Tafel diagram data.

Example 4

20g of the self-crosslinking cationic acrylate emulsion prepared in example 3 (the content of the self-crosslinking monomer N-hydroxyethyl acrylamide is 0.8%) was mixed with phytic acid in different amounts, stirred for 30min and then added with deionized water to prepare 200g of passivation solution.

The pretreatment and passivation process of the ADC12 aluminum alloy sheet were the same as in example 3, and the properties of the passivated aluminum alloy sheet film layer are as shown in table 5 below.

TABLE 5

The results in table 5 show that the polyhydroxy group and the amino group on the surface of the self-crosslinking cationic acrylate latex particle endow the emulsion with excellent compatibility and have good balance performance on positive and negative charges, the prepared cationic acrylate emulsion/phytic acid composite resin passivation solution has good stability, and the synergistic effect of the cationic acrylate emulsion and the anionic phytic acid corrosion inhibitor endows the resin passivation film with excellent corrosion resistance. When the content of the phytic acid is 1%, the phytic acid reacts with the aluminum matrix to form a chemical conversion film on the surface of the aluminum matrix, so that the penetration of corrosive media can be effectively hindered, and the aluminum matrix is protected. When the phytic acid content is lower than 1%, a complete chemical conversion film is not formed sufficiently; when the phytic acid content is more than 1%, excessive phytic acid may affect the denseness of the resin passivation film to cause a decrease in corrosion resistance.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.

Claims

1. A cationic acrylate emulsion characterized by: comprises the steps of (a) preparing a substrate,

wherein, by taking the total mass of the cationic acrylate emulsion as hundred percent, the content of the functional monomer aqueous solution is 40 percent, the content of the self-crosslinking monomer is 0.8 percent, the content of the acrylate monomer is 35 percent, the content of the emulsifier is 0.41 percent, the content of the initiator is 0.2 percent, and the balance is water;

the functional monomer aqueous solution is a polymerizable polyhydroxy organic amine functional monomer, and the preparation method comprises the following steps: placing glycidyl methacrylate in an ice water bath, dropwise adding diethanolamine while stirring, continuously stirring for reaction after dropwise adding is finished to obtain a polymerizable polyhydroxy organic amine functional monomer, dissolving the polymerizable polyhydroxy organic amine functional monomer in water, and adjusting the pH value to 5-6 to obtain a functional monomer aqueous solution; the molar ratio of the glycidyl methacrylate to the diethanolamine is 1:1, the mass concentration of the functional monomer in the functional monomer aqueous solution is 4 percent;

wherein the self-crosslinking monomer is N-hydroxyethyl acrylamide;

wherein the acrylate monomer is a mixture of two or more of methyl methacrylate, butyl acrylate, acrylic acid and methyl acrylate;

the emulsifier is cetyl trimethyl ammonium bromide;

the initiator is azodiisobutyramidine hydrochloride.

2. The cationic acrylate emulsion of claim 1 wherein: and continuously stirring for reaction to obtain the polymerizable polyhydroxy organic amine functional monomer, wherein the continuous stirring reaction time is 3-4 h.

3. The cationic acrylate emulsion of claim 1 or 2 wherein: the polymerizable polyhydroxy organic amine functional monomer is dissolved in water, and the pH is adjusted to 5-6, wherein the pH is adjusted by acetic acid or phosphoric acid.

4. A method for preparing the cationic acrylate emulsion according to any one of claims 1 to 3, characterized in that: comprises the steps of (a) preparing a mixture of a plurality of raw materials,

dissolving an initiator in a certain amount of water to obtain an initiator aqueous solution;

dissolving a self-crosslinking monomer in a functional monomer aqueous solution to obtain a functional monomer mixed aqueous solution;

uniformly mixing acrylate monomers to obtain an acrylate monomer mixed solution;

putting the emulsifier and the rest water into a reaction kettle, stirring and dissolving, adding 30% of the functional monomer mixed aqueous solution and 10% of the acrylate monomer mixed aqueous solution, stirring and heating to 72 ℃, and adding 30% of the initiator aqueous solution;

after reacting for 15min, simultaneously dropwise adding the residual initiator aqueous solution, the functional monomer mixed aqueous solution and the acrylate monomer mixed solution into a polymerization system for 2.5-3 h;

reacting for 15min, heating to 82 ℃, reacting for 90min at constant temperature, naturally cooling and filtering to obtain self-crosslinking cationic acrylic acid cationic emulsion;

the method comprises the following steps of dissolving an initiator in a certain amount of water to obtain an initiator aqueous solution, wherein the water addition amount is 4 percent based on the total mass percentage of the cationic acrylate emulsion.

5. The method for preparing the cationic acrylate emulsion according to claim 4, wherein: the self-crosslinking monomer is N-hydroxyethyl acrylamide; the acrylate monomer is two or more of methyl methacrylate, butyl acrylate, acrylic acid and methyl acrylate; the emulsifier is cetyl trimethyl ammonium bromide; the initiator is azodiisobutyramidine hydrochloride.

6. The method for preparing the cationic acrylate emulsion according to claim 4 or 5, wherein: the functional monomer aqueous solution is polymerizable polyhydroxy organic amine functional monomer, and the preparation method comprises the steps of putting glycidyl methacrylate into an ice water bath, dropwise adding diethanolamine while stirring, continuously stirring for reaction after dropwise adding is finished to obtain polymerizable polyhydroxy organic amine functional monomer, dissolving the polymerizable polyhydroxy organic amine functional monomer in water, and adjusting the pH value to 5-6 to obtain the functional monomer aqueous solution;

the molar ratio of the glycidyl methacrylate to the diethanolamine is 1:1, the mass concentration of the functional monomer in the functional monomer aqueous solution is 4%.

7. Use of the cationic acrylate emulsion according to any one of claims 1 to 3 in a resin passivation solution for aluminum alloy surfaces.

8. The use of claim 7, wherein: the resin passivation solution for the surface of the aluminum alloy comprises,

the resin passivation solution comprises a cationic acrylate emulsion and water, wherein the content of the cationic acrylate emulsion is 10% and the balance is water, wherein the total mass of the resin passivation solution is calculated in percentage by weight.

9. The use of claim 7, wherein: the resin passivation solution for the surface of the aluminum alloy comprises,

the resin passivation solution comprises a cationic acrylate emulsion, phytic acid and water, wherein the content of the cationic acrylate emulsion is 10%, the content of the phytic acid is 1.0% and the balance is the water, wherein the total mass of the resin passivation solution is calculated in percentage by weight.