A kind of polyurea modified epoxy resin anticorrosive coating and preparation method thereof

Abstract

The invention discloses a polyurea modified epoxy resin anticorrosive coating and a preparation method thereof, and belongs to the field of anticorrosion technology. The coating prepared by the invention is a coating that connects the flexibility and excellent mechanical properties of polyurea to the epoxy resin molecular chain by chemical grafting, and is combined with diisocyanate at a higher temperature to form a trimer, or to form an oxazolidinone ring structure with an epoxy group, so as to further improve the strength of the coating, thereby improving its adhesion and service life, and having excellent corrosion resistance, good stability, low cost, and a simple and easy preparation process.

Description

Technical Field

[0001] The invention belongs to the technical field of anti-corrosion, and in particular relates to a polyurea modified epoxy resin anti-corrosion coating and a preparation method thereof. Background Art

[0002] Atmospheric corrosion of metal materials is one of the most common types of corrosion. This type of corrosion has caused huge economic losses to various countries and caused serious casualties. At present, the more mature anti-corrosion methods mainly include: hot-dip galvanizing, anti-corrosion coatings and cathodic protection. Among them, the anti-corrosion coating protection method has become one of the main means of metal anti-corrosion due to its low cost and simple construction process. Epoxy resin anti-corrosion coatings are widely used in anti-corrosion coatings for metal materials because of their strong adhesion, good corrosion resistance and low cost. However, the coating of pure epoxy resin anti-corrosion coatings has poor flexibility, poor aging resistance, and low moisture and heat resistance, which makes the coating very brittle and prone to holes or cracks, thereby losing its anti-corrosion performance. Summary of the invention

[0003] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0004] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0005] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a polyurea-modified epoxy resin anticorrosive coating.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for preparing a polyurea modified epoxy resin anticorrosive coating, comprising:

[0007] The epoxy resin, catalyst and solvent are uniformly mixed, heated, diisocyanate is slowly added, refluxed, cooled to room temperature, polyaspartic acid ester is added, and the reaction is continued for 0.5 to 2 hours to obtain polyurea-modified epoxy resin;

[0008] According to weight, 30-80 parts of polyurea modified epoxy resin, 2-40 parts of pigments and fillers, 0.1-8 parts of dispersants, are mixed and ground to a fineness of less than 45 μm, and then 0.1-0.5 parts of leveling agent, 0.1-1 parts of anti-settling agent, 0.1-1 parts of defoaming agent are added, and the balance is solvent, the solvent is 10-20 parts, and mixed evenly to obtain coating component A;

[0009] Add the curing agent into component A of the coating and mix evenly to obtain a polyurea modified epoxy resin anti-corrosion coating.

[0010] As a preferred embodiment of the preparation method of the present invention, the epoxy resin is uniformly mixed with a catalyst and a solvent, wherein the epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, and polyphenol glycidyl ether epoxy resin containing hydroxyl groups on the structural chain; the catalyst is dibutyltin dilaurate or tetrabutyl titanate; and the solvent is one or more of ethyl acetate, butyl acetate, PMA, DBE, xylene, cyclohexanone, and a mixture of xylene and butanol.

[0011] As a preferred embodiment of the preparation method of the present invention, the epoxy resin, the catalyst and the solvent are uniformly mixed, wherein the mass ratio of the epoxy resin, the catalyst and the solvent is 1:0.0075:1.

[0012] As a preferred embodiment of the preparation method of the present invention, the heating is performed at a temperature of 80 to 180°C.

[0013] As a preferred embodiment of the preparation method of the present invention, the diisocyanate is slowly added, wherein the diisocyanate is one of hexamethylene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate; and the molar ratio of the isocyanate in the diisocyanate to the hydroxyl in the epoxy resin is 1.5 to 6:1.

[0014] As a preferred embodiment of the preparation method of the present invention, wherein: the reflux reaction time is 1.5 to 4 hours and the reflux temperature is 80 to 180°C.

[0015] As a preferred embodiment of the preparation method of the present invention, wherein: polyaspartic acid ester is added, wherein the molar ratio of amino group to residual isocyanate in the polyaspartic acid ester is 1:1-1.05; and the mass ratio of polyaspartic acid ester to epoxy resin is 1:2-1:5.

[0016] As a preferred embodiment of the preparation method of the present invention, the balance is a solvent, wherein the solvent is one or more of ethyl acetate, butyl acetate, propylene glycol methyl ether acetate PMA, and dibasic acid ester DBE.

[0017] As a preferred embodiment of the preparation method of the present invention, the curing agent is added to the coating component A and mixed evenly, wherein the curing agent is one or more of amine, phenol, and phenolic curing agents, and the content of the curing agent is 10% to 30% of the epoxy resin content.

[0018] Another object of the present invention is to overcome the deficiencies in the prior art and provide a polyurea modified epoxy resin anticorrosive coating.

[0019] Beneficial effects of the present invention:

[0020] The coating prepared by the present invention is obtained by chemically grafting the flexibility and excellent mechanical properties of polyurea onto the epoxy resin molecular chain, and combining with diisocyanate at a relatively high temperature to form a trimer or an oxazolidone ring structure with an epoxy group, so as to further improve the strength of the coating, thereby improving its adhesion and service life. The coating has excellent corrosion resistance, good stability, low cost and a simple and easy preparation process. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0022] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0024] In the embodiments of the present invention, the dosage forms of the dispersant, leveling agent, defoaming agent and anti-settling agent are: dispersant (7631, Guangzhou Siluoke Chemical Co., Ltd.), leveling agent (8488, Guangzhou Siluoke Chemical Co., Ltd.), defoaming agent (4019, Guangzhou Siluoke Chemical Co., Ltd.), and anti-settling agent (7456F, Guangzhou Siluoke Chemical Co., Ltd.).

[0025] In the following examples, the polyaspartic acid resin F420 can be replaced by Bayer's NH1420, and the polyaspartic acid resin F520 can be replaced by Bayer's NH1520.

[0026] Example 1

[0027] (1) Preparation of polyurea modified epoxy resin

[0028] In a three-necked flask, add 20g of epoxy resin E44 and 20g of PMA solvent, stir evenly, then add 0.15g of tetrabutyl titanate, heat and stir, condense and reflux, heat to 160°C, add 20g of HDI, and react for 2 hours. After cooling to 80°C, add 8.7g of F520 and react for 2 hours, then cool to room temperature. Polyurea modified epoxy resin is obtained.

[0029] (2) Preparation of polyurea modified epoxy resin coating component A

[0030] Weigh 50g of the above-mentioned polyurea modified epoxy resin, add 1g of dispersant, stir evenly, then add 10g of pigment and filler, stir and disperse evenly, then grind with a ball mill to a fineness of less than 45μm, finally add 0.4g of leveling agent, 0.3g of defoaming agent, 0.4g of anti-settling agent, and an appropriate amount of ethyl acetate to adjust the viscosity, stir evenly to obtain coating component A.

[0031] (3) Preparation of polyurea modified epoxy resin coating

[0032] Add 5 g of curing agent T31 as coating component B into coating component A and mix well to obtain modified epoxy resin coating.

[0033] Example 2

[0034] (1) Preparation of polyurea modified epoxy resin

[0035] In a three-necked flask, add 20g of epoxy resin E44 and 20g of PMA solvent, stir evenly, then add 0.15g of dibutyltin dilaurate, heat and stir, condense and reflux, heat to 160°C, add 20g of HDI, and react for 2 hours. After cooling to 80°C, add 8.7g of F520 and react for 2 hours, then cool to room temperature. Polyurea-modified epoxy resin is obtained.

[0036] (2) Preparation of polyurea modified epoxy resin coating component A

[0037] Weigh 50g of the above-mentioned polyurea modified epoxy resin, add 1g of dispersant, stir evenly, then add 10g of pigment and filler, stir and disperse evenly, then grind with a ball mill to a fineness of less than 45μm, finally add 0.4g of leveling agent, 0.3g of defoaming agent, 0.4g of anti-settling agent, and an appropriate amount of ethyl acetate to adjust the viscosity, stir evenly to obtain coating component A.

[0038] (3) Preparation of polyurea modified epoxy resin coating

[0039] Add 5 g of curing agent T31 as coating component B into coating component A and mix well to obtain modified epoxy resin coating.

[0040] Example 3

[0041] (1) Preparation of polyurea modified epoxy resin

[0042] In a three-necked flask, add 20g of epoxy resin E44 and 20g of ethyl acetate solvent, stir evenly, then add 0.15g of dibutyltin dilaurate, heat and stir, condense and reflux, heat to 80°C, add 5g of HDI, react for 4 hours, then add 4.35g of F520 and react for 2 hours, and cool to room temperature to obtain a polyurea-modified epoxy resin.

[0043] (2) Preparation of polyurea modified epoxy resin coating component A

[0044] Weigh 50g of the above-mentioned polyurea modified epoxy resin, add 1g of dispersant, stir evenly, then add 10g of pigment and filler, stir and disperse evenly, then grind with a ball mill to a fineness of less than 45μm, finally add 0.4g of leveling agent, 0.3g of defoaming agent, 0.4g of anti-settling agent, and an appropriate amount of ethyl acetate to adjust the viscosity, stir evenly to obtain coating component A.

[0045] (3) Preparation of polyurea modified epoxy resin coating

[0046] Add 5 g of curing agent T31 as coating component B into coating component A and mix well to obtain modified epoxy resin coating.

[0047] Example 4

[0048] (1) Preparation of polyurea modified epoxy resin

[0049] In a three-necked flask, add 20g of epoxy resin E44 and 20g of butyl acetate solvent, stir evenly, then add 0.15g of dibutyltin dilaurate, heat and stir, condense and reflux, heat to 130°C, add 10g of HDI, and react for 3 hours. After cooling to 80°C, add 6.5g of F520 and react for 2 hours, then cool to room temperature. Polyurea-modified epoxy resin is obtained.

[0050] (2) Preparation of polyurea modified epoxy resin coating component A

[0051] Weigh 50g of the above-mentioned polyurea modified epoxy resin, add 1g of dispersant, stir evenly, then add 10g of pigment and filler, stir and disperse evenly, then grind with a ball mill to a fineness of less than 45μm, finally add 0.4g of leveling agent, 0.3g of defoaming agent, 0.4g of anti-settling agent, and an appropriate amount of ethyl acetate to adjust the viscosity, stir evenly to obtain coating component A.

[0052] (3) Preparation of polyurea modified epoxy resin coating

[0053] Add 5 g of curing agent T31 as coating component B into coating component A and mix well to obtain modified epoxy resin coating.

[0054] Example 5

[0055] (1) Preparation of polyurea modified epoxy resin

[0056] In a three-necked flask, add 20g of epoxy resin E44, 10g of butyl acetate solvent, and 10g of PMA solvent, stir evenly, then add 0.15g of tetrabutyl titanate, heat and stir, condense and reflux, heat to 150°C, add 20g of HDI, and react for 2 hours. After cooling to 80°C, add 8.7g of F520 and react for 2 hours, and cool to room temperature. Polyurea-modified epoxy resin is obtained.

[0057] (2) Preparation of polyurea modified epoxy resin coating component A

[0058] Weigh 50g of the above-mentioned polyurea modified epoxy resin, add 1g of dispersant, stir evenly, then add 10g of pigment and filler, stir and disperse evenly, then grind with a ball mill to a fineness of less than 45μm, finally add 0.4g of leveling agent, 0.3g of defoaming agent, 0.4g of anti-settling agent, and an appropriate amount of ethyl acetate to adjust the viscosity, stir evenly to obtain coating component A.

[0059] (3) Preparation of polyurea modified epoxy resin coating

[0060] Add 5 g of curing agent T31 as coating component B into coating component A and mix well to obtain modified epoxy resin coating.

[0061] Example 6

[0062] (1) Preparation of polyurea modified epoxy resin

[0063] In a three-necked flask, add 20g of epoxy resin E44, 5g of DBE, and 15g of PMA solvent, stir evenly, then add 0.15g of tetrabutyl titanate, heat and stir, condense and reflux, heat to 180°C, add 20g of HDI, and react for 1.5 hours. After cooling to 80°C, add 8.7g of F520 and react for 2 hours, and cool to room temperature. Polyurea-modified epoxy resin is obtained.

[0064] (2) Preparation of polyurea modified epoxy resin coating component A

[0065] Weigh 50g of the above-mentioned polyurea modified epoxy resin, add 1g of dispersant, stir evenly, then add 10g of pigment and filler, stir and disperse evenly, then grind with a ball mill to a fineness of less than 45μm, finally add 0.4g of leveling agent, 0.3g of defoaming agent, 0.4g of anti-settling agent, and an appropriate amount of ethyl acetate to adjust the viscosity, stir evenly to obtain coating component A.

[0066] (3) Preparation of polyurea modified epoxy resin coating

[0067] Add 5 g of curing agent T31 as coating component B into coating component A and mix well to obtain modified epoxy resin coating.

[0068] Example 7

[0069] (1) Preparation of polyurea modified epoxy resin

[0070] In a three-necked flask, add 20g of epoxy resin E44 and 20g of PMA solvent, stir evenly, then add 0.15g of tetrabutyl titanate, heat and stir, condense and reflux, heat to 160°C, add 20g of HDI, and react for 2 hours. After cooling to 80°C, add 8.3g of F420 and react for 0.5 hours, and cool to room temperature. Polyurea modified epoxy resin is obtained.

[0071] (2) Preparation of polyurea modified epoxy resin coating component A

[0072] Weigh 50g of the above-mentioned polyurea modified epoxy resin, add 1g of dispersant, stir evenly, then add 10g of pigment and filler, stir and disperse evenly, then grind with a ball mill to a fineness of less than 45μm, finally add 0.4g of leveling agent, 0.3g of defoaming agent, 0.4g of anti-settling agent, and an appropriate amount of ethyl acetate to adjust the viscosity, stir evenly to obtain coating component A.

[0073] (3) Preparation of polyurea modified epoxy resin coating

[0074] Add 5 g of curing agent T31 as coating component B into coating component A and mix well to obtain modified epoxy resin coating.

[0075] The modified epoxy resin coatings prepared in Examples 1 to 7 and the pure E44 coating were tested for performance, and the test results are shown in Table 1:

[0076] Table 1 Coating performance test results

[0077]

[0078]

[0079] Comparative Example 1

[0080] (1) Preparation of polyurea modified epoxy resin

[0081] In a three-necked flask, add 20g of epoxy resin E44 and 19g of PMA solvent, stir evenly, then add 1.15g of tetrabutyl titanate, heat and stir, condense and reflux, heat to 160°C, add 20g of HDI, and react for 2 hours. After cooling to 80°C, add 8.7g of F520 and react for 2 hours, then cool to room temperature. A polyurea-modified epoxy resin is obtained, in which a large amount of catalyst solid particles are present.

[0082] (2) Preparation of polyurea modified epoxy resin coating component A

[0083] Weigh 50g of the above-mentioned polyurea modified epoxy resin, add 1g of dispersant, stir evenly, then add 10g of pigment and filler, stir and disperse evenly, then grind with a ball mill to a fineness of less than 45μm, finally add 0.4g of leveling agent, 0.3g of defoaming agent, 0.4g of anti-settling agent, and an appropriate amount of ethyl acetate to adjust the viscosity, stir evenly to obtain coating component A.

[0084] (3) Preparation of polyurea modified epoxy resin coating

[0085] Add 5 g of curing agent T31 as coating component B into coating component A and mix well to obtain modified epoxy resin coating.

[0086] Comparative Example 2

[0087] (1) Preparation of polyurea modified epoxy resin

[0088] In a three-necked flask, add 20g of epoxy resin E44 and 20g of PMA solvent, stir evenly, then add 0.15g of tetrabutyl titanate, heat and stir, condense and reflux, heat to 60°C, add 20g of HDI, and react for 2 hours. After cooling to 80°C, add 8.7g of F520 and react for 2 hours, and cool to room temperature. The polyurea-modified epoxy resin is obtained, which gels and forms a solid state after being placed, and subsequent experiments cannot be carried out.

[0089] Comparative Example 3

[0090] (1) Preparation of polyurea modified epoxy resin

[0091] In a three-necked flask, add 20g of epoxy resin E44, 15g of DBE, and 5g of PMA solvent, stir evenly, then add 0.15g of tetrabutyl titanate, heat and stir, condense and reflux, heat to 200°C, add 20g of HDI, and react for 2 hours. After cooling to 80°C, add 8.7g of F520 and react for 2 hours, and cool to room temperature. Polyurea-modified epoxy resin is obtained.

[0092] (2) Preparation of polyurea modified epoxy resin coating component A

[0093] Weigh 50g of the above-mentioned polyurea modified epoxy resin, add 1g of dispersant, stir evenly, then add 10g of pigment and filler, stir and disperse evenly, then grind with a ball mill to a fineness of less than 45μm, finally add 0.4g of leveling agent, 0.3g of defoaming agent, 0.4g of anti-settling agent, and an appropriate amount of ethyl acetate to adjust the viscosity, stir evenly to obtain coating component A.

[0094] (3) Preparation of polyurea modified epoxy resin coating

[0095] Add 5 g of curing agent T31 as coating component B into coating component A and mix well to obtain modified epoxy resin coating.

[0096] Comparative Example 4

[0097] (1) Preparation of polyurea modified epoxy resin

[0098] In a three-necked flask, add 20g of epoxy resin E44 and 20g of PMA solvent, stir evenly, then add 0.15g of tetrabutyl titanate, heat and stir, condense and reflux, heat to 160°C, add 20g of HDI, and react for 2 hours. After cooling to 80°C, add 3g of F520 and react for 2 hours, then cool to room temperature. Polyurea modified epoxy resin is obtained.

[0099] (2) Preparation of polyurea modified epoxy resin coating component A

[0100] Weigh 50g of the above-mentioned polyurea modified epoxy resin, add 1g of dispersant, stir evenly, then add 10g of pigment and filler, stir and disperse evenly, then grind with a ball mill to a fineness of less than 45μm, finally add 0.4g of leveling agent, 0.3g of defoaming agent, 0.4g of anti-settling agent, and an appropriate amount of ethyl acetate to adjust the viscosity, stir evenly to obtain coating component A.

[0101] (3) Preparation of polyurea modified epoxy resin coating

[0102] Add 5 g of curing agent T31 as coating component B into coating component A and mix well to obtain modified epoxy resin coating.

[0103] Comparative Example 5

[0104] (1) Preparation of polyurea modified epoxy resin

[0105] In a three-necked flask, add 20g of epoxy resin E44 and 20g of PMA solvent, stir evenly, then add 0.15g of tetrabutyl titanate, heat and stir, condense and reflux, heat to 160°C, add 20g of HDI, and react for 2 hours. After cooling to 80°C, add 12g of F520 and react for 2 hours, and cool to room temperature. A polyurea-modified epoxy resin is obtained, and the viscosity of the polyurea-modified epoxy resin is relatively high.

[0106] (2) Preparation of polyurea modified epoxy resin coating component A

[0107] Weigh 50g of the above-mentioned polyurea modified epoxy resin, add 1g of dispersant, stir evenly, then add 10g of pigment and filler, stir and disperse evenly, then grind with a ball mill to a fineness of less than 45μm, finally add 0.4g of leveling agent, 0.3g of defoaming agent, 0.4g of anti-settling agent, and an appropriate amount of ethyl acetate to adjust the viscosity, stir evenly to obtain coating component A.

[0108] (3) Preparation of polyurea modified epoxy resin coating

[0109] Add 5 g of curing agent T31 as coating component B into coating component A and mix well to obtain modified epoxy resin coating.

[0110] The modified epoxy resin coatings and pure E44 coatings prepared in Example 1 and Comparative Examples 1 to 5 were tested for performance, and the test results are shown in Table 2:

[0111] Table 2

[0112]

[0113]

[0114] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A method for preparing a polyurea modified epoxy resin anticorrosive coating, characterized in that: include, Preparation of polyurea modified epoxy resin: In a three-necked flask, add 20g of epoxy resin E44 and 20g of PMA solvent, stir evenly, then add 0.15g of tetrabutyl titanate, heat and stir, condense and reflux, heat to 160°C, then add 20g of hexamethylene diisocyanate HDI, react for 2 hours, cool to 80°C, then add 8.7g of polyaspartic acid ester F520 and react for 2 hours, cool to room temperature, and obtain a polyurea-modified epoxy resin; Preparation of polyurea modified epoxy resin coating component A: Weigh 50g of the above-mentioned polyurea modified epoxy resin, add 1g of dispersant, stir evenly, then add 10g of pigment and filler, stir and disperse evenly, then grind with a ball mill to a fineness of less than 45μm, finally add 0.4g of leveling agent, 0.3g of defoamer, 0.4g of anti-settling agent, and an appropriate amount of ethyl acetate to adjust the viscosity, stir evenly to obtain coating component A; Preparation of polyurea modified epoxy resin coating: Add 5 g of curing agent T31 as coating component B into coating component A and mix well to obtain modified epoxy resin coating.

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