CN108976437B

CN108976437B - Nonionic emulsifier, epoxy emulsion, and preparation method and application thereof

Info

Publication number: CN108976437B
Application number: CN201810537562.8A
Authority: CN
Inventors: 郭家振; 陈超
Original assignee: Bauhinia Paints Shanghai Co ltd
Current assignee: Bauhinia Coating (shanghai) Co Ltd
Priority date: 2018-05-30
Filing date: 2018-05-30
Publication date: 2021-07-06
Anticipated expiration: 2038-05-30
Also published as: CN108976437A

Abstract

The invention provides a nonionic epoxy resin emulsifier, which has a structure shown in a formula ER-1 or ER-2; the invention also provides a preparation method of the nonionic epoxy resin emulsifier; the invention also provides a non-ionic epoxy emulsion and a preparation method and application thereof; the nonionic epoxy emulsion provided by the invention has the advantages of small diameter, good stability, no layered water separation phenomenon when tested by 10000rpm centrifugal separation for 30 minutes and stored at normal temperature for 6 months, small change of the particle diameter and the epoxy equivalent, and excellent protection performance on a metal welding area.

Description

Nonionic emulsifier, epoxy emulsion, and preparation method and application thereof

Technical Field

The invention belongs to the technical field of chemical industry, relates to a nonionic emulsifier, an epoxy emulsion, and preparation methods and applications thereof, and particularly relates to a nonionic emulsifier containing imidazoline rings, an epoxy emulsion, and preparation methods and applications thereof.

Background

Compared with the traditional solvent-based epoxy anticorrosive paint, the waterborne epoxy-polyamine cured anticorrosive paint has remarkable progress in reducing VOC (volatile organic compound) emission, however, the surface tension of water is higher, so that the wettability of the paint on a metal substrate is inferior to that of the solvent-based paint, and in addition, no matter what method is used for preparing the waterborne epoxy, a certain amount of hydrophilic groups (nonionic chain segments, cationic groups or anionic groups) are always introduced, so that the anticorrosive performance is slightly different from that of the solvent-based paint.

It is reported that, according to the statistics of more than 20 years, 85% of corrosion of the coated metal member is first initiated from the weld joint due to slight differences in crystal phase structure, material composition and internal stress between the welded material and the metal matrix, thereby causing galvanic corrosion. Although the weld joint corrosion is a local corrosion problem relative to surrounding metal, the local corrosion phenomenon tends to develop more quickly than large-area corrosion, and because the corrosion action range is concentrated, the danger of the local corrosion phenomenon is high, the welding strength is possibly weakened, cracks or corrosion perforations are generated, and the corrosion prevention in the metal weld joint area faces more challenges.

CN105801868A discloses a preparation method of a bifunctional epoxy resin emulsifier and an emulsion, which comprises the following specific preparation steps: (1) trimellitic anhydride (TMA) and a catalyst (boron trifluoride ether) are added to polyethylene glycol (PEG4000), and the temperature is raised for reaction. (2) Adding proper amount of bisphenol A epoxy resin E-44 into the reaction solution, heating and continuing to react to obtain the multi-block epoxy resin emulsifier (PEGDET for short). (3) Mixing a proper amount of epoxy resin and an emulsifier, slowly dripping deionized water at a certain temperature, stirring at a high speed until the viscosity of the system is suddenly reduced, causing phase inversion phenomenon of the system, and continuously adding water to obtain the water-based epoxy resin emulsion. The epoxy resin emulsion prepared by the method does not disclose a specific applicable field.

CN105505132B discloses a water-based epoxy resin coating and a preparation method thereof, wherein the water-based epoxy resin coating is obtained by mixing and emulsifying epoxy resin and an emulsifier, and then mixing the mixture with a curing agent; wherein the epoxy resin is E44 type epoxy resin; the emulsifier is prepared by reacting E44 type epoxy resin with polyethylene glycol; the curing agent is prepared by the reaction of E44 type epoxy resin and methyl glucosamine. The water-based epoxy resin coating disclosed by the invention is only added with a small amount of water and does not contain an organic solvent, and a coating film obtained by coating the coating is transparent and firm, has moderate hardness and resists the corrosion of the organic solvent. The epoxy resin coating disclosed by the method only has the performance of resisting the corrosion of an organic solvent, and the problem of corrosion resistance of metal welding cannot be solved.

The invention discloses CN102942683A, belongs to the technical field of epoxy resin emulsifiers, and particularly relates to a composite epoxy resin emulsifier and a preparation method thereof. The composite epoxy resin emulsifier comprises the following components in parts by weight: the component 1 is epoxy bisphenol A diglycidyl ether resin, the weight shares are 60-70 shares; the component 2 is 2-bisphenol A epoxy amino-5-sulfonic acid-benzoic acid, and the weight portion is 15-25 portions; the component 3 is 2-bisphenol A epoxy amino-5-sulfonic acid group-butyl benzoate, and the weight portion is 5 to 10 portions; the component 4 is 2-bisphenol A epoxy amino-5-sulfonic acid group-ethyl benzoate monobutyl ether, the weight portion is 5-10 portions; the component 5 is 2-polyether alcohol glycidyl ether amino-5-sulfonic group-benzoic acid, and the weight portion is 0.1 to 0.5. The emulsion obtained by using the emulsifier has the advantages of high solid content, small particle size, low viscosity, high stability and convenient construction. However, the epoxy emulsifier prepared by the method has complex components and complicated preparation process, and cannot be applied to solving the problem of corrosion resistance of metal welding.

At present, the waterborne epoxy resin has little concern about corrosion resistance of metal welding positions, and the invention aims to further improve the corrosion resistance of a waterborne epoxy resin coating, particularly strengthen the protection of the waterborne epoxy resin coating on metal welding positions.

Disclosure of Invention

The invention aims to provide a nonionic epoxy emulsion and a preparation method and application thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a nonionic epoxy resin emulsifier having a structure represented by formula ER-1 or ER-2:

wherein, in the formulae ER-1 and ER-2, R₁Is H or methyl, R₂Is C₂～C₇(may be, for example, C)₂、C₃、C₄、C₅、C₆Or C₇) Any one of alkylene, substituted vinyl, substituted cyclohexyl, unsaturated bond-containing substituted cyclohexyl, endomethylenecyclohexyl and substituted phenyl of (1), 15<x<120 (e.g., 16, 20, 40, 60, 70, 80, 90, 100, 110, or 120), y is 0 to 35 (e.g., 0, 5, 8, 12, 15, 20, 25, 30, or 35), and x and y are integers;

e in formulae ER-1 and ER-2 has the following structure:

wherein R is₃is-CH₂-or

The value of n is an integer of 0 to 3 (for example, 0, 1,2, or 3).

The nonionic epoxy resin emulsifier provided by the invention contains a hydrophilic imidazoline ring, the hydrophilicity is realized by a nonionic long chain on the 2-position such as a polyethylene glycol polymer, and is different from the water solubility realized by salinization of the imidazoline ring through chloralkane or bromalkane quaternary ammonium, ER-1 and ER-2 do not contain halogen, and the aqueous solution is weakly acidic to neutral, so that the imidazoline ring can not be hydrolyzed when the epoxy emulsion emulsified by the emulsifier is stored for a long time, and Cl introduced by quaternization is avoided^-Or Br^-Obviously weakening the antiseptic property, and the long chain at the 2-position of the imidazoline ring has no biological toxicity.

The epoxy hydrophobic long chain on the 1-position of the five-membered heterocyclic ring of the imidazoline ring not only provides shielding protection for the imidazoline ring, but also participates in crosslinking during curing, thereby further strengthening the anticorrosion performance of the coating.

In the invention, due to the unique structure of the imidazoline ring, lone pair electrons on the N atom can form an electron donor-electron acceptor combination with the empty d orbit of the iron atom on the surface of the steel, can be tightly adsorbed on the surface of the metal, has an anode passivation function, and increases the corrosion potential of the metal, thereby having good effect of inhibiting the metal corrosion.

In the invention, the compound with the structure shown by ER-1 is a linear epoxy emulsifier, and the compound with the structure shown by ER-2 is a Y-type epoxy emulsifier with double lipophilic ends.

In the invention, in the structure of E, chemical bonds at two ends of the structural formula represent chemical bonds which can be connected in ER-1 or ER-2; r in the structure of E₃In, e.g. -CH₂-, the bonds at the two ends represent methylene groups at R₃With keys attached to the corresponding positions.

In a second aspect, the present invention provides a method for preparing the nonionic epoxy resin emulsifier of the first aspect, the method comprising:

when the nonionic epoxy resin emulsifier has a structure shown in ER-1, the preparation method comprises the steps of carrying out addition reaction on a compound shown in a formula I and epoxy resin to obtain a compound shown in ER-1;

when the nonionic epoxy resin emulsifier has a structure shown in ER-2, the preparation method comprises the steps of carrying out addition reaction on a compound shown in a formula II and epoxy resin to obtain a compound shown in ER-2;

wherein, the compounds shown in formula I and formula II are as follows:

wherein R is₁Is H or methyl, R₂Is C₂～C₇Any one of alkylene, substituted vinyl, substituted cyclohexyl, unsaturated bond-containing substituted cyclohexyl, endomethylenecyclohexyl or substituted phenyl of (1), 15<x<And 120, y is 0-35, and x and y are integers.

In the present invention, the epoxy resin reacted with the compound of formula I and the compound of formula II is the same epoxy resin, and the compound of formula I and the compound of formula II are both subjected to addition reaction with the epoxy resin under the same conditions. The epoxy resin is generally bisphenol F or bisphenol A epoxy resin with an Epoxy Equivalent (EEW) of 160-1000 (wherein the epoxy equivalent corresponds to the value of n in E in the structures of ER-1 and ER-2, and a person skilled in the art can select a proper epoxy equivalent according to the value of n).

In the invention, the longer the chain of the epoxy resin serving as the hydrophobic chain end of the nonionic epoxy resin emulsifier is, the more favorable the adsorption stability of the epoxy resin during emulsification and the shielding of corrosive media after film forming are facilitated, but the viscosity reduction during processing and the crosslinking density during curing are not facilitated. Preferably an epoxy resin having an epoxy equivalent of 500 to 1000.

Preferably, the equivalent ratio of the compound represented by the formula I to the epoxy resin is 1 (2-2.2), and can be 1:2, 1:2.1 or 1:2.2, for example.

Preferably, the equivalent ratio of the compound represented by the formula II to the epoxy resin is 1 (2-2.2), and may be 1:2, 1:2.1 or 1:2.2, for example.

In the present invention, the end point of the addition reaction can be determined by detecting a change in the epoxy equivalent or the tertiary amine value.

Preferably, the temperature of the addition reaction is 70 to 90 ℃, and may be, for example, 70 ℃, 72 ℃, 75 ℃, 78 ℃, 80 ℃, 85 ℃ or 90 ℃.

Preferably, the compound shown in the formula I is prepared by performing half-esterification reaction on hydrophilic molecules and acid anhydride, and then performing amidation reaction and ring-closure reaction on the hydrophilic molecules and ethylenediamine in a solvent.

Preferably, the compound shown in the formula II is prepared by performing half-esterification reaction on hydrophilic molecules and acid anhydride, and then performing amidation reaction and ring-closure reaction on the compound and diethylenetriamine in a solvent.

In the present invention, the amidation reaction is first carried out, and after a certain period of time has elapsed, the ring-closure reaction is carried out by raising the temperature, and dehydration is started to form the imidazoline ring structure.

Preferably, the hydrophilic molecule comprises polyethylene glycol, polyethylene glycol monomethyl ether, or a polyethylene glycol-poly (1, 2-propylene glycol) block polymer.

Preferably, the number average molecular weight of the hydrophilic molecule is 1200 to 15000, and may be 1200, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 12000, 13000, or 15000, for example.

Preferably, the hydrophilic molecule is polyethylene glycol monomethyl ether with the number average molecular weight of 2000-10000.

In the invention, the number average molecular weight of the hydrophilic molecule is related to the values of x and y in formula I and formula II, and a person skilled in the art can select the hydrophilic molecule with specific number average molecular weight according to the values of x and y.

In the invention, when the number average molecular weight is lower than 2000, the hydrophilicity of hydrophilic molecules is not enough, and the stability of the emulsion is not good enough; on the other hand, if the molecular weight is too high, the crystallinity is strong, and the corrosion resistance is lowered by introducing more hydrophilic groups.

Preferably, the acid anhydride comprises any one of succinic anhydride, maleic anhydride, glutaric anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl hexahydrophthalic anhydride, endomethylene tetrahydrophthalic anhydride or phthalic anhydride, preferably any one of succinic anhydride, maleic anhydride or glutaric anhydride.

In the present invention, the acid anhydride is not limited to the above-mentioned ones, and any of the alkane type acid anhydrides, alicyclic type acid anhydrides and aromatic type acid anhydrides which can be involved in the half-esterification reaction may be used.

Preferably, the molar ratio of the anhydride to the hydrophilic molecule is (1-1.2):1, and may be, for example, 1:1, 1.05:1, 1.1:1, 1.15:1, or 1.2:1, and preferably (1-1.05): 1.

Preferably, the half-esterification reaction is carried out in the presence of a first catalyst.

Preferably, the first catalyst comprises any one of p-toluenesulfonic acid, methanesulfonic acid or triphenylphosphine, or a combination of at least two thereof.

Preferably, the temperature of the half-esterification reaction is 100 to 130 ℃, for example, 100 ℃, 105 ℃, 110 ℃, 115 ℃, 120 ℃, 125 ℃ or 130 ℃.

Preferably, the temperature of the amidation reaction is 110 to 180 ℃, for example, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃ or 180 ℃ and the like.

Preferably, the amidation reaction time is 2-3 h, for example, 2h, 2.1h, 2.2h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3h, etc.

Preferably, the temperature of the ring-closure reaction is 200 to 250 ℃, for example, 200 ℃, 210 ℃, 220 ℃, 230 ℃, 240 ℃ or 250 ℃.

Preferably, the ring closure reaction time is 3-4 h, for example, 3h, 3.1h, 3.3h, 3.5h, 3.6h, 3.7h, 3.8h, 3.9h or 4h, etc.

Preferably, the solvent is toluene and/or xylene.

In the present invention, the reaction is generally carried out under reflux of the solvent, and the end point of the reaction can be judged according to the amount of water divided during the reaction.

Preferably, both the amidation reaction and the ring-closure reaction are carried out in the presence of a second catalyst.

Preferably, the second catalyst comprises any one of alumina, calcium oxide or borax or a combination of at least two of the foregoing.

In the invention, in the process of preparing the compound shown in the formula I and the compound shown in the formula II, the conditions of hydrophilic molecules, acid anhydride, half-esterification reaction, amidation reaction and ring-closure reaction are the same; the only difference between the two preparation methods is that ethylenediamine is used in the preparation of the compound of formula I, while diethylenetriamine is used in the preparation of the compound of formula I.

In a third aspect, the present invention provides a nonionic epoxy emulsion, which comprises, by mass, 5% to 15% (e.g., 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, etc.) of the nonionic epoxy resin emulsifier according to the first aspect, 35% to 50% (e.g., 35%, 38%, 40%, 42%, 43%, 45%, 46%, 47%, 48%, 49%, or 50%), 0% to 5% (e.g., 0, 1%, 2%, 3%, 4%, 5%), and 45% to 60% (e.g., 45%, 48%, 50%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, or 60%) of an epoxy resin, a diluent, and water.

The nonionic epoxy emulsion provided by the invention has small particle size and good stability, is tested by centrifugal separation at 10000rpm for 30 minutes, is stored at normal temperature for 6 months, has no layered water separation phenomenon, and has small change of particle size and epoxy equivalent.

Preferably, the nonionic epoxy emulsion further comprises an alcohol ether material.

Preferably, the alcohol ether substance is propylene glycol methyl ether or propylene glycol butyl ether.

Preferably, the alcohol ether substance is 0 to 15% by mass in the nonionic epoxy emulsion, and may be 0, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%, for example.

Preferably, the epoxy resin comprises a bisphenol a type epoxy resin or a bisphenol F type epoxy resin.

Preferably, the epoxy resin has an epoxy equivalent of 160 to 1000, and may be, for example, 160, 200, 300, 500, 800, 900, 1000, or the like. Preferably 400 to 600.

In the present invention, the epoxy resin used for preparing the epoxy emulsion is substantially the same as the epoxy resin participating in the addition reaction of the compound of formula I and the compound of formula II.

Preferably, the diluent comprises an alcohol ether organic solvent, C₄～C₁₄Monoglycidyl ether or C₄～C₁₄Any one of diglycidyl ethers or a combination of at least two thereof.

Preferably, the alcohol ether type organic solvent includes propylene glycol methyl ether and/or propylene glycol butyl ether.

Preferably, said C₄～C₁₄Monoglycidyl ethers include any one or a combination of at least two of octyl glycidyl ether, ortho-cresyl glycidyl ether, or dodecyl glycidyl ether, for example, where typical but non-limiting combinations include: octyl glycidyl ether and dodecyl glycidyl ether.

Preferably, said C₄～C₁₄The diglycidyl ether includes hexanediol diglycidyl ether and/or polypropylene glycol diglycidyl ether.

In the present invention, C is preferably used₆～C₁₄A mono-or diglycidyl ether of (a).

In a fourth aspect, the present invention provides a method for preparing the nonionic epoxy emulsion according to the third aspect, the method comprising: uniformly mixing the nonionic epoxy resin emulsifier, the epoxy resin, the diluent and optionally alcohol ether substances, adding water, and stirring and mixing to obtain the nonionic epoxy emulsion.

Preferably, the temperature for mixing is 50-60 ℃, for example, can be 50 ℃, 51 ℃, 52 ℃, 53 ℃, 54 ℃, 55 ℃, 56 ℃, 57 ℃, 58 ℃, 59 ℃ or 60 ℃.

Preferably, the water is continuously and slowly dripped into the mixed liquid within the time of 0.5-1 h.

Preferably, the rotation speed of the stirring is 1000-2000 rpm, for example, 1000rpm, 1100rpm, 1200rpm, 1300rpm, 1400rpm, 1500rpm, 1600rpm, 1700rpm, 1800rpm, 1900rpm or 2000 rpm.

In the invention, after the water is stirred and mixed, the resin is subjected to phase inversion and is kept for 30 minutes, and the particle size D can be obtained₉₀Epoxy emulsion with the diameter less than or equal to 1 mu m.

In a fifth aspect, the invention provides a use of the nonionic epoxy emulsion of the third aspect in corrosion prevention of metal welding.

For example, the non-ionic epoxy emulsion aqueous polyamine-epoxy adduct type curing agent is prepared into an epoxy anticorrosive coating, so that the epoxy anticorrosive coating has good anticorrosive performance, and particularly, the protection of a metal welding area is improved.

Compared with the prior art, the invention has the following beneficial effects:

(1) the nonionic epoxy resin emulsifier provided by the invention contains a hydrophilic imidazoline ring, the hydrophilicity is realized by a nonionic long chain on the 2-position such as a polyethylene glycol polymer, and is different from the water solubility realized by salinization of the imidazoline ring through chloralkane or bromalkane quaternary ammonium, ER-1 and ER-2 do not contain halogen, and the aqueous solution is weakly acidic to neutral, so that the imidazoline ring can not be hydrolyzed when the epoxy emulsion emulsified by the emulsifier is stored for a long time, and Cl introduced by quaternization is avoided^-Or Br^-Obviously weakening the antiseptic property, and the long chain at the 2-position of the imidazoline ring has no biotoxicity; the epoxy hydrophobic long chain on the 1-position of the five-membered heterocyclic ring of the imidazoline ring not only provides shielding protection for the imidazoline ring, but also participates in crosslinking during curing, thereby further strengthening the anticorrosion performance of the coating.

(2) The nonionic epoxy emulsion provided by the invention has small particle size and good stability, is tested by centrifugal separation at 10000rpm for 30 minutes, is stored at normal temperature for 6 months, has no layered water separation phenomenon, and has small change of particle size and epoxy equivalent.

(3) The nonionic epoxy emulsion provided by the invention has good corrosion resistance, particularly improves the protection of a metal welding area, and has wide application prospect and higher application value.

Drawings

FIG. 1 is a schematic view of fusion welded stainless steel flat plates in application example 2 of the present invention.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

The specific model information of the raw materials involved in the following examples of the present invention is as follows:

NPEL-128, 128S, NPES-301, 302 is bisphenol A type epoxy resin, available from south Asia resin (Kunshan).

Octyl glycidyl ether, dodecyl glycidyl ether, o-cresyl glycidyl ether, hexanediol diglycidyl ether and other raw materials are industrial grade and purchased from Hedysbi chemical trade.

Polyethylene glycol monomethyl ether was purchased from the sean chemical industry.

VEH2188 is tradename of a new epoxy curing agent;

reagents such as p-toluenesulfonic acid, ethylenediamine, diethylenetriamine and the like are purchased from Shanghai chemical reagent supply stations.

The test method comprises the following steps:

1) particle size: malvern particle sizer MS 3009.

2) Viscosity: brookfield viscometer.

3) Film thickness: GB 1764-1989.

4) Hardness: GB/T6739-2006.

5) Centrifugal stability: high speed centrifuge Allegra 64R.

6) Salt water resistance: GB/T1733-1993.

7) Neutral salt spray test: test GB/T1771-2007, evaluating foaming ASTM D714, corrosion rating ASTM D610, cross-hatch diffusion corrosion ASTM D1654.

8) Adhesion force: GB/T9286-1998.

9) Testing the substrate:

cold-rolled steel sheet: G3101/SS41, size 2 × 7.50 × 15mm, and electric grinding treatment;

welding a steel plate: a 304 stainless steel welding flat plate with the size of 2 multiplied by 10 multiplied by 20mm, according to the standard GB/T15970.8-2005, electric grinding and manual grinding are combined;

monitoring the reaction process:

epoxy equivalent: the acetone hydrochloride method, all expressed on solids basis.

Amine value: ASTM D2074.

Amine equivalent weight: based on the theoretical calculation of solid, can react with one mole of epoxy group.

Acid value: the acid-base titration method is expressed in units of mgKOH/g based on the solid content.

Example 1

This example prepares a nonionic epoxy emulsion by the following procedure

(1) In a 1000ml four-neck flask equipped with a thermometer, a nitrogen gas conduit, a stirrer, a water separator and an electric heating jacket, 580g of polyethylene glycol monomethyl ether MPEG5000 (number average molecular weight Mn: 5000) were introduced into the flask at 100 to 110 ℃ with N₂Purifying for 30-60min, adding 20g of methyl tetrahydrophthalic anhydride (MTHPA) and 0.1% of p-toluenesulfonic acid catalyst, keeping introducing nitrogen, reacting at 110 ℃ for 4-5 h, and measuring the acid value to be less than or equal to 13.5 mgKOH/g;

(2) adding 10g of ethylenediamine and 60g of toluene (which can be put into two batches, and the water separator is filled with toluene in advance), reacting for 2-3 h at 110-120 ℃, slowly heating to 210 ℃ for 1-2 h, keeping the temperature at 210-220 ℃ for continuing to react for 2-3 h (the water yield is about 4g, and the primary amine value is less than or equal to 5mgKOH/g), cooling to 160 ℃, discharging the solvent and the byproducts in the water separator, and performing vacuum extraction for 1 h;

(3) further cooling to 85 ℃, adding 140g of NPES-cc301(EEW: 450-500) epoxy resin and 75g of propylene glycol methyl ether PM, maintaining the temperature at 85-90 ℃ and reacting for 3h (tertiary amine value is 12-16mgKOH/g), obtaining about 825g of emulsifier with solid content of 90%, and naming the emulsifier as Ex-1/ER-1;

(4) an epoxy emulsion was prepared as follows:

in an emulsifying tank with a heating jacket, epoxy resin NPES-301, propylene glycol methyl ether PM, dodecyl glycidyl ether and Ex-1/ER-1 (solid content of 90 percent) are uniformly premixed at 60 ℃, deionized water is slowly dripped, the rotating speed of a dispersion disc is 1000-2000 rpm, phase inversion is carried out for about 40 minutes, stirring is carried out for 15 minutes, and the solid content is 51 percent, and the particle size D is obtained₉₀800nm epoxy emulsion, 500 to 550 EEW and 1000 to 3000cps viscosity.

The meaning of "Ex-1/ER-1" is that the emulsifier is named as Ex-1 and has a structure shown in the general formula ER-1.

Example 2

(1) The same reaction conditions as in example 1 are adopted in the step, 587g of MPEG8000 (number average molecular weight 8000) and 12.8g of methyl tetrahydrophthalic anhydride are used for preparing half ester, and the end acid value is less than or equal to 8 mgKOH/g;

(2) adding 10g of diethylenetriamine and 60g of toluene (which can be put into two batches, and the water separator is filled with toluene in advance), reacting for 2-3 h at 140-180 ℃, heating to 210 ℃, keeping the temperature at 210-220 ℃, continuing to react for 3h (the water yield is about 2.6g, and the primary amine value is less than or equal to 11mgKOH/g), cooling to 160 ℃, discharging the solvent and the by-product in the water separator, and performing vacuum extraction for 1 h;

(3) further cooling to 85 ℃, adding 162g of NPES-301(EEW: 450-500) epoxy resin and 90g of propylene glycol monomethyl ether, maintaining the temperature at 85-90 ℃ and reacting for 3h (the tertiary amine value is 12-16mgKOH/g), obtaining about 860g of emulsifier with the solid content of 90%, and naming as Ex-2/ER-2;

(4) an epoxy emulsion was prepared as follows:

using the emulsification method of example 1, a solid content of 52% and a particle diameter D of₉₀600nm epoxy emulsion, EEW 500-550, viscosity: 1000 to 3000 cps.

Example 3

(1) The same reaction conditions as in example 1 are adopted in the step, 584g of polyethylene glycol PEG6000 (number average molecular weight Mn is 6000) and 15.7g of hexahydrophthalic anhydride are half-esterified, and the end acid value is less than or equal to 10 mgKOH/g;

(2) the step (2) adopts the same reaction conditions as the step (2) in the embodiment 2, imidazoline is prepared by replacing diethylenetriamine with 8.5g of ethylenediamine, the water yield is about 3.4g, and the end point primary amine value is less than or equal to 5 mgKOH/g;

(3) further cooling to 85 ℃, adding 134g of NPES-302(EEW: 600-700) epoxy resin and 90g of propylene glycol monomethyl ether, maintaining the temperature at 85-90 ℃ and reacting for 3h (tertiary amine value is 11-14mgKOH/g) to obtain about 837g of emulsifier with solid content of 90%, and naming as Ex-3/ER-1;

(4) an epoxy emulsion was prepared as follows:

using the emulsification method of example 1, the solid content of 51% and the particle diameter D were obtained₉₀800nm epoxy emulsion, 500 to 550 EEW and 2000 to 6000cps viscosity.

Example 4

(1) 590g of Pluronic P123 (trade name of BASF, data molecular weight Mn 5750, PO chain unit content 30%) and 10.5g of maleic anhydride, acid value 11mgKOH/g or less were used as end points in this step using the same reaction conditions as in example 1;

(2) according to the method of the step (2) of the embodiment 2, 12.8g of diethylenetriamine is added to prepare imidazoline, and when the effluent water is 3.6g, the product is obtained;

(3) according to the method of the step (3) in the example 1, 100g of NPEL-128S epoxy resin (EEW:205-225) and 78g of propylene glycol methyl ether are added to prepare an emulsifier which is named as EX-4/ER-2, the tertiary amine value is 20-22 mgKOH/g, and the solid content is 90 percent;

(4) an epoxy emulsion having a solid content of 52% and a particle diameter D was prepared in the same ratio and emulsification method as in step (4) of example 2₉₀580nm, 500 to 550 EEW and 1000 to 3000 cps.

Comparative example 1

The difference between the comparative example and the example 1 is that half ester of MPEG5000-MTHPA is synthesized firstly, then 140g of NPES-301 epoxy and 78g of propylene glycol methyl ether are added, the reaction is maintained at 110-130 ℃ for 3 hours, the acid value is less than or equal to 1mgKOH/g, and the emulsifier with the solid content of 90 percent is obtained and named as C-1;

then, using the same formulation and emulsification method as the fourth step in example 1, EX-1/ER-1 was replaced with only C-1 in equal amount to obtain an epoxy emulsion with a solid content of 51%, EEW 500-550, D850 nm, and a viscosity of 1000-3000 cps.

Comparative example 2

556g of polyethylene glycol monomethyl ether MPEG5000 is put into N at 100-110 DEG C₂After purification for 30min, 45g of NPEL-128(EEW184-190) was added thereto, and boron trifluoride ether solution (9g) was slowly dropped while maintaining the temperature at 80 ℃. The time is about 30min, the temperature is raised to 110 ℃ in the later period, and the EEW is measured to 4800-;

then, using the same formulation and emulsification method as the fourth step in example 1, EX-1/ER-1 was replaced with only C-2 in equal amount to obtain an epoxy emulsion having a solid content of 51%, EEW 500-.

Application example 1

Performance testing of the varnish on Cold-rolled Steel sheets

The epoxy emulsions prepared in examples 1 to 4 and comparative examples 1 to 2 were mixed with a curing agent VEH2188 to prepare varnishes having an amine equivalent/epoxy equivalent ratio of 0.85/1 (stoichiometric calculation), dried at room temperature for 24 hours, cured at 80 ℃ for 3 hours at an accelerated speed, scribed on the plate surface, and soaked in 5% saline at room temperature for 7 days, and the test results are shown in table 1.

TABLE 1

Application example 2

Salt spray test of colored paint on metal welding plate

The concentrated slurry was prepared as in Table 2 and sanded to a fineness of less than or equal to 30 μm.

TABLE 2

Raw materials	Specification or supplier	Dosage of
			Deionized water	K≤15μS/cm	35.6
Disperbyk190	BYK dispersant	3.0
			Foamex 830	Tego antifoaming agent	0.2
DPnB	DOW	1.0
			ZMP antirust pigment	Kaiba	15.0
Superfine barium sulfate	Shaharli book	10.0
			Bentone LT	Haiming Si	0.2
Mica powder	Wet sericite, 325 mesh	5.0
			R-930 titanium white	(DuPont)	30.0
NV,％	——	60.3
			∑	——	100.0
Fineness of fineness	——	≤30μ

A white anticorrosion primer is prepared by using VEH2188 curing agent and amine equivalent/epoxy equivalent ratio of 0.85/1 (stoichiometric), PVC is designed to be 33%, the white anticorrosion primer is sprayed on a metal plate with a welding seam, a schematic diagram of a sprayed fusion welding stainless steel flat plate is shown in figure 1, after drying for 24 hours at room temperature, the white anticorrosion primer is accelerated and cured for 3 hours at 80 ℃, no cross cutting exists, neutral salt fog exists, and the observed results are shown in table 3.

TABLE 3

As can be seen from the comparison between examples 1-4 and comparative examples 1-2, the epoxy emulsion prepared in comparative examples 1-2 contains no imidazoline ring in the structure of the emulsifier, and the prepared varnish has a large corrosion expansion range after being soaked for 7 d; when the epoxy emulsion is sprayed on a metal plate with a welding seam, the epoxy emulsion prepared in the examples 1-4 still only keeps slightly rusted after a 1000h salt spray test, while the epoxy emulsion prepared in the comparative examples 1-2 still has serious rusty and foams and falls off at the welding seam.

The applicant states that the present invention is illustrated by the above examples of the nonionic emulsifier, the epoxy emulsion, the preparation method and the application thereof, but the present invention is not limited to the above detailed method, i.e. the present invention is not meant to be dependent on the above detailed method for implementation. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

Claims

1. A nonionic epoxy resin emulsifier, characterized in that the emulsifier has a structure as shown in formula ER-1 or ER-2:

wherein, in the formulae ER-1 and ER-2, R₁Is H or methyl, R₂Is C₂～C₇Any one of alkylene, substituted vinyl, substituted cyclohexyl, unsaturated bond-containing substituted cyclohexyl, endomethylenecyclohexyl and substituted phenyl of (1), 15<x<120, y is 0-35, and x and y are integers;

e in formulae ER-1 and ER-2 has the following structure:

wherein R is₃is-CH₂-or

The value of n is an integer of 0-3.

2. The method of claim 1, wherein the method comprises:

wherein, the compounds shown in formula I and formula II are as follows:

3. The preparation method of claim 2, wherein the equivalent ratio of the compound represented by the formula I to the epoxy resin is 1 (2-2.2).

4. The method according to claim 2, wherein the equivalent ratio of the compound represented by the formula II to the epoxy resin is 1 (2-2.2).

5. The method according to claim 2, wherein the addition reaction temperature is 70 to 90 ℃.

6. The preparation method of claim 2, wherein the compound represented by formula I is prepared by half-esterifying a hydrophilic molecule with an acid anhydride, and then amidating and ring-closing with ethylenediamine in a solvent.

7. The preparation method of claim 2, wherein the compound represented by formula II is prepared by half-esterifying a hydrophilic molecule with an acid anhydride, and then amidating and ring-closing reactions with diethylenetriamine in a solvent.

8. The method of claim 6 or 7, wherein the hydrophilic molecule comprises polyethylene glycol, polyethylene glycol monomethyl ether, or a polyethylene glycol-poly (1, 2-propylene glycol) block polymer.

9. The method according to claim 6 or 7, wherein the hydrophilic molecule has a number average molecular weight of 1200 to 15000.

10. The method according to claim 6 or 7, wherein the hydrophilic molecule is polyethylene glycol monomethyl ether having a number average molecular weight of 2000 to 10000.

11. The method according to claim 6 or 7, wherein the acid anhydride comprises any one of succinic anhydride, maleic anhydride, glutaric anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl hexahydrophthalic anhydride, endomethylene tetrahydrophthalic anhydride, or phthalic anhydride.

12. The production method according to claim 6 or 7, wherein the acid anhydride is any one of succinic anhydride, maleic anhydride, or glutaric anhydride.

13. The method according to claim 6 or 7, wherein the molar ratio of the acid anhydride to the hydrophilic molecule is (1-1.2): 1.

14. The method according to claim 6 or 7, wherein the molar ratio of the acid anhydride to the hydrophilic molecule is (1-1.05): 1.

15. The process according to claim 6 or 7, wherein the half-esterification reaction is carried out in the presence of a first catalyst.

16. The method of claim 15, wherein the first catalyst comprises any one of p-toluenesulfonic acid, methanesulfonic acid, or triphenylphosphine, or a combination of at least two thereof.

17. The method according to claim 6 or 7, wherein the temperature of the half-esterification reaction is 100 to 130 ℃.

18. The method according to claim 6 or 7, wherein the temperature of the amidation reaction is 110 to 180 ℃.

19. The method according to claim 6 or 7, wherein the amidation reaction time is 2 to 3 hours.

20. The method according to claim 6 or 7, wherein the temperature of the ring-closure reaction is 200 to 250 ℃.

21. The preparation method according to claim 6 or 7, wherein the ring closure reaction time is 3-4 h.

22. The method according to claim 6 or 7, wherein the solvent is toluene and/or xylene.

23. The production method according to claim 6 or 7, wherein the amidation reaction and the ring-closure reaction are both performed in the presence of a second catalyst.

24. The method of claim 23, wherein the second catalyst comprises any one of alumina, calcium oxide, or borax, or a combination of at least two thereof.

25. The nonionic epoxy emulsion is characterized by comprising 5-15% of the nonionic epoxy resin emulsifier, 35-50% of epoxy resin, 0-5% of diluent and 45-60% of water according to the mass percentage.

26. The nonionic epoxy emulsion of claim 25 wherein the nonionic epoxy resin emulsion further comprises an alcohol ether.

27. The nonionic epoxy emulsion of claim 26 wherein the alcohol ether is propylene glycol methyl ether or propylene glycol butyl ether.

28. The nonionic epoxy emulsion according to claim 26, wherein the alcohol ether-based substance is present in the nonionic epoxy emulsion in an amount of 0 to 15% by mass.

29. The nonionic epoxy emulsion of claim 25 wherein the epoxy resin comprises a bisphenol a type epoxy resin or a bisphenol F type epoxy resin.

30. The nonionic epoxy emulsion according to claim 25, wherein the epoxy resin has an epoxy equivalent of 160 to 1000.

31. The nonionic epoxy emulsion according to claim 25, wherein the epoxy resin has an epoxy equivalent of 400 to 600.

32. The nonionic epoxy emulsion of claim 25 wherein the diluent comprises an alcohol ether organic solvent, C₄～C₁₄Monoglycidyl ether or C₄～C₁₄Any one of diglycidyl ethers or a combination of at least two thereof.

33. The nonionic epoxy emulsion of claim 32 wherein the alcohol ether organic solvent comprises propylene glycol methyl ether and/or propylene glycol butyl ether.

34. The nonionic epoxy emulsion of claim 32 wherein C is₄～C₁₄The monoglycidyl ether includes any one of octyl glycidyl ether, o-cresyl glycidyl ether or dodecyl glycidyl ether or a combination of at least two thereof.

35. The nonionic epoxy emulsion of claim 32 wherein C is₄～C₁₄The diglycidyl ether includes hexanediol diglycidyl ether and/or polypropylene glycol diglycidyl ether.

36. The method of any one of claims 25-35, wherein the method comprises: uniformly mixing the nonionic epoxy resin emulsifier, the epoxy resin, the diluent and optionally alcohol ether substances, adding water, and stirring and mixing to obtain the nonionic epoxy emulsion.

37. The method of claim 36, wherein the temperature of the blending is 50-60 ℃.

38. The method as claimed in claim 36, wherein the water is slowly added dropwise to the mixed liquid over a period of 0.5 to 1 hour.

39. The method according to claim 36, wherein the stirring is performed at a rotation speed of 1000 to 2000 rpm.

40. Use of a non-ionic epoxy emulsion according to any one of claims 25 to 35 for corrosion protection of metal welds.