Epoxy-modified oxazolidine and preparation method thereof and epoxy-hybridized aspartame polyurea coating

Abstract

The present application relates to an epoxy-modified oxazolidine and a preparation method and an epoxy-hybridized asparagine polyurea coating in the technical field of asparagine polyurea coating. The epoxy-modified oxazolidine is prepared by reacting the primary amine group of a primary amine compound with the epoxy group of an epoxy compound through an epoxy ring-opening reaction, and then undergoing dehydration condensation with a carbonyl-containing compound, and at least one of the primary amine compound and the epoxy compound is a monofunctional compound; the structural formula of the epoxy-modified oxazolidine is shown in formula (1) or formula (2). After the construction of the epoxy-hybridized asparagine polyurea coating containing the epoxy-modified oxazolidine is completed, the coating film absorbs moisture in the air to hydrolyze the epoxy-modified oxazolidine to release NH and OH, which participate in cross-linking and curing with polyaspartic acid ester and isocyanate curing agent, making the coating more compact, thereby improving the adhesion between the coating and the substrate and the salt spray resistance; at the same time, the coating has the characteristics of room temperature curing, long application period and long operation time.

Description

Technical Field

[0001] The present application relates to the technical field of asparagine polyurea coatings, and in particular to an epoxy-modified oxazolidine and a preparation method thereof, and an epoxy-hybridized asparagine polyurea coating. Background Art

[0002] Polyaspartic acid ester is prepared by Michael reaction of aliphatic or alicyclic diamine or polyamine with maleate or fumarate. Polyaspartic acid ester is usually used in the field of coatings. Aspartic acid polyurea coating can be prepared by mixing polyaspartic acid ester with isocyanate. Compared with general amino resin, polyaspartic acid ester resin reacts slower with isocyanate. The reason is that maleate or fumarate has steric hindrance and induction effect, which can effectively delay the reaction rate of polyaspartic acid ester resin with isocyanate. Therefore, the prepared aspartic acid polyurea coating has a longer construction time, and its coating construction method can be spraying, rolling, scraping, etc., without the need for professional and expensive construction equipment. In addition, the reactivity of the secondary amine group in polyaspartic acid ester is higher than that of the hydroxyl group of conventional polyurethane resin, and the reaction speed is faster, which can achieve rapid curing. In addition, polyaspartic acid ester has a small molecular weight and low viscosity, so it can be constructed without adding solvents. Therefore, asparagus polyurea coating is a high-solid, environmentally friendly coating that is widely used in waterproofing, flooring, and anti-corrosion fields.

[0003] However, polyaspartic acid ester has a small molecular weight and a high content of ester bonds in the molecule. The aspartic polyurea coating obtained after reacting with isocyanate has poor hydrophobicity and water resistance, resulting in poor salt spray resistance of the coating. This is mainly because salt spray itself is in a supersaturated water mist state. The poor hydrophobicity and water resistance of aspartic polyurea coating will cause salt spray to more easily penetrate the paint film and cause corrosion. Therefore, due to the poor salt spray resistance, aspartic polyurea coating is difficult to promote in heavy corrosion protection fields such as engineering machinery, ships, and offshore wind power.

[0004] Based on the above problems, the research attempts to modify polyaspartic acid esters to improve the salt spray resistance of aspartic acid polyurea coatings. For example, the polyaspartic acid ester resin is chemically modified by epoxy resin to improve the salt spray resistance, but the epoxy-modified polyaspartic acid ester resin has extremely high viscosity and contains highly active secondary amines and hydroxyl groups, which greatly shortens the operation time of aspartic acid polyurea coatings and is not conducive to construction; the salt spray resistance of aspartic acid polyurea coatings can be improved by cold-blending epoxy resins, but the added epoxy resin is difficult to form a film with the polyaspartic acid ester resin, which reduces the performance of the paint film.

[0005] Therefore, it is necessary to provide a new method for improving the salt spray resistance of aspartame polyurea coating. Summary of the invention

[0006] In order to address the deficiencies of the prior art, the present application provides an epoxy-modified oxazolidine and an epoxy-hybrid asparagine polyurea coating containing the epoxy-modified oxazolidine. The epoxy-modified oxazolidine added to the coating does not affect the curing performance of the coating, has the characteristics of room temperature curing, long application period and long operation time, and the epoxy-modified oxazolidine releases hydroxyl groups after hydrolysis. The epoxy-hybrid asparagine polyurea coating prepared using the epoxy-modified oxazolidine has excellent adhesion to the substrate and excellent salt spray resistance.

[0007] Therefore, the first aspect of the present application provides an epoxy-modified oxazolidine, which is obtained by reacting a primary amine group of a primary amine compound with an epoxy group of an epoxy compound through an epoxy ring-opening reaction, followed by dehydration condensation with a carbonyl-containing compound; and at least one of the primary amine compound and the epoxy compound is a monofunctional compound.

[0008] In the present application, the term "monofunctional compound" refers to a compound having only one reactive functional group; specifically, if the primary amine compound is a monofunctional compound, it means that there is only one primary amine group (-NH 2 ), if the epoxy compound is a monofunctional compound, it means that there is only one epoxy group (-CH(O)CH) in the epoxy compound.

[0009] In the present application, when preparing the epoxy-modified oxazolidine, at least one of the primary amine compound and the epoxy compound used is a monofunctional compound, which can avoid excessive cross-linking of the primary amine compound and the epoxy compound during the reaction, thereby affecting the improved performance of the epoxy-modified oxazolidine on the asparagine polyurea coating.

[0010] In some embodiments, when the primary amine compound is a monofunctional compound, the structural formula of the epoxy-modified oxazolidine is as shown in formula (1);

[0011]

[0012] When the epoxy compound is a monofunctional compound, the structural formula of the epoxy-modified oxazolidine is as shown in formula (2);

[0013]

[0014] Among them, X in formula (1) 1 For the primary amine compound to remove -NH 2 The residue remaining after the group, Y 1 is the residue remaining after removing a -CH(O)CH epoxy groups from the epoxy compound; in formula (2), X 2 For the primary amine compound, remove b -NH 2 The residue remaining after the group, Y 2is the residue remaining after removing the -CH(O)CH epoxy group from the epoxy compound; R in formula (1) and formula (2) 1 and R 2 Each is independently selected from any one of H, C1-C18 alkyl and C6-C18 aralkyl; said a and b are each independently selected from any integer from 1 to 6.

[0015] It should be noted that when the primary amine compound and the epoxy compound are both monofunctional compounds, the structural formula of the epoxy-modified oxazolidine can be as shown in formula (1) or formula (2), and a in formula (1) or b in formula (2) is 1.

[0016] Specifically, when the primary amine compound is a monofunctional compound, the reaction formula for synthesizing the epoxy-modified oxazolidine is as follows:

[0017]

[0018] When the epoxy compound is a monofunctional compound, the reaction formula for synthesizing the epoxy-modified oxazolidine is as follows:

[0019]

[0020] In the present application, R in formula (1) and formula (2) 1 and R 2 Can be the same or different. In some preferred embodiments, the R 1 and R 2 Each is independently selected from any one of H, a C1-C6 alkyl group and a C6-C12 aralkyl group.

[0021] In some preferred embodiments, a is 1, 2, 3 or 4, and b is 1, 2 or 3.

[0022] By controlling the values ​​of a and b within the above ranges, the cross-linking reaction between the primary amine compound and the epoxy compound can be moderate, thereby improving the performance of the coating containing the epoxy-modified oxazolidine.

[0023] In some embodiments, the primary amine compound is selected from at least one of aromatic amines, cyclic amines, aliphatic amines and phenolic amines, and the epoxy compound is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, phenolic epoxy resin, hydrogenated epoxy resin, cardanol-modified epoxy resin, epoxy soybean oil, biphenyl epoxy resin, naphthalene ring epoxy resin, glycidyl ether epoxy resin, glycidyl ester epoxy resin and glycidyl amine epoxy resin.

[0024] In some specific embodiments, the primary amine compound is selected from at least one of diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, aniline, m-phenylenediamine, 1,3-cyclohexanedimethylamine, γ-aminopropyltriethoxysilane, 1,3-propylenediamine, pentamethylenediamine, 2-methyl-1,5-pentanediamine, cyclohexanediamine, methylcyclohexanediamine, 2-amino-2-methyl-1-propanol, diethyltoluenediamine, dimethylthiotoluenediamine, 4-phenylbutylamine, cyclohexylamine, n-butylamine, isooctylamine, 2,4,4-trimethyl-2-pentylamine and oleylamine.

[0025] In some specific embodiments, the epoxy compound is selected from at least one of E44 epoxy resin, E51 epoxy resin, F44 epoxy resin, F51 epoxy resin, NC513 epoxy resin, NC514 epoxy resin, NC547 epoxy resin, phenyl glycidyl ether, benzyl glycidyl ether, o-tolyl glycidyl ether, triglycidyl isocyanurate, N,N,N',N'-tetracyclyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetra(oxiranylmethyl)-1,3-phenylenediamine, resorcinol diglycidyl ether, diglycidyl phthalate, diglycidyl hexahydrophthalate, cyclohexene oxide, epoxy soybean oil, tert-butyl glycidyl ether and γ-glycidyloxypropyltrimethoxysilane.

[0026] In the present application, the specific types of primary amine compounds and epoxy compounds used will affect the type of substituents on the oxazolidine ring of the epoxy-modified oxazolidine finally obtained, as well as the degree of crosslinking of the primary amine compound and the epoxy compound, thereby affecting the reactivity of the epoxy-modified oxazolidine with the isocyanate in the curing agent during the crosslinking and curing process of the coating, and ultimately affecting the salt spray resistance of the coating.

[0027] In some embodiments, the carbonyl-containing compound is selected from at least one of benzaldehyde, phenylacetaldehyde, n-butyraldehyde, isobutyraldehyde, isovaleraldehyde, 2,2-dimethyl-3-lauroyloxy-propionaldehyde, butanone, methyl isobutyl ketone, methyl acetoacetate and ethyl acetoacetate.

[0028] The specific type of the carbonyl-containing compound described in the present application will affect the reaction rate of the dehydration condensation, as well as the R 1 and R 2 type, which in turn affects the performance of the coating.

[0029] The second aspect of the present application provides a method for preparing the epoxy-modified oxazolidine as described in the first aspect of the present application, the method comprising the following steps:

[0030] S1, under the protection of an inert gas, mixing the epoxy compound and the primary amine compound and performing an epoxy ring-opening reaction to obtain a β-amino alcohol to be modified;

[0031] S2, mixing the β-amino alcohol to be modified with the carbonyl-containing compound, performing dehydration condensation, and adding a water-containing solvent for reflux dehydration;

[0032] S3, after the dehydration is completed, removing the excess carbonyl-containing compound to obtain the epoxy-modified oxazolidine.

[0033] In the present application, the epoxy-modified oxazolidine can be efficiently synthesized by the above method, and the purity of the epoxy-modified oxazolidine in the reaction product is relatively high.

[0034] In some embodiments, the conditions of the epoxy ring-opening reaction are: reaction temperature: 40-90° C., reaction time 24-36 hours. In the present application, the epoxy compound and the primary amine compound may be mixed by dripping the epoxy compound into the primary amine compound, and the temperature during dripping does not exceed the temperature of the epoxy ring-opening reaction.

[0035] In the present application, during the dehydration condensation of the β-amino alcohol to be modified and the carbonyl-containing compound, a water-carrying solvent is also required to be added to the reaction system to remove the water generated during the dehydration condensation process by reflux, so that the dehydration condensation reaction can be carried out efficiently and quickly. The water-carrying solvent is generally a solvent that can azeotrope with water, such as cyclohexane, toluene and xylene.

[0036] In some embodiments, the molar ratio of the primary amine compound, the epoxy compound and the carbonyl-containing compound is 1:(0.05-1):(0.05-4) based on the molar ratio of their respective functional groups; wherein the functional group of the primary amine compound is -NH 2 , the functional group of the epoxy compound is -CH(O)CH, and the functional group of the carbonyl-containing compound is -C=O.

[0037] The carbonyl-containing compound added in the present application may be excessive, and the excess carbonyl-containing compound may be removed by vacuum distillation. The present application controls the amount of the primary amine compound, the epoxy compound and the carbonyl-containing compound within the above range, so that the epoxy-modified oxazolidine obtained by the reaction can better improve the salt spray resistance of the coating.

[0038] The third aspect of the present application provides an epoxy hybrid asparagine polyurea coating, which includes component A and component B, wherein component A includes the epoxy-modified oxazolidine as described in the first aspect of the present application or the epoxy-modified oxazolidine prepared by the method described in the second aspect, and component B is an isocyanate curing agent.

[0039] The A component of the coating described in the present application contains epoxy-modified oxazolidine, and the coating film absorbs moisture in the air after the coating construction is completed, so that the epoxy-modified oxazolidine is hydrolyzed to release -NH and -OH, which participate in cross-linking and curing with polyaspartic acid ester and isocyanate curing agent, thereby solving the problem that cold-mixed epoxy resin in the prior art solution cannot participate in the film formation of asparagine polyurea, and at the same time, the density of the coating is higher through cross-linking and curing, thereby improving the adhesion between the coating and the substrate and the salt spray resistance. In addition, the prepared epoxy-modified oxazolidine greatly reduces the effect of molecular hydrogen bonds due to the blocking of highly active secondary amine groups and hydroxyl groups. Compared with the epoxy-modified asparagine polyurea coating in the prior art solution, the coating of the present application has a lower viscosity and a longer application period.

[0040] In some embodiments, the component A further comprises polyaspartic acid ester, and at least one of a dispersant, an anti-settling agent, a defoamer, an anti-sagging agent, a filler, a coloring pigment, an anti-rust pigment, a molecular sieve, a leveling agent, a silane coupling agent and a solvent.

[0041] In the present application, the filler may be, for example, silicon micropowder and / or talcum powder, the coloring pigment may be, for example, titanium dioxide; the anti-rust pigment may be, for example, at least one of zinc phosphate, micaceous iron powder and APW-1.

[0042] In some preferred embodiments, the component A and the component B in the coating respectively include the following components in parts by weight:

[0043] The component A comprises: 10-30 parts of the epoxy-modified oxazolidine, 10-30 parts of polyaspartic acid ester, 0.5-1 parts of dispersant, 0-4 parts of anti-settling agent, 0.2-1 parts of defoamer, 0.1-0.3 parts of anti-sagging agent, 10-35 parts of filler, 0-15 parts of coloring pigment, 5-20 parts of anti-rust pigment, 0-5 parts of molecular sieve, 0.1-0.5 parts of leveling agent, 0-2 parts of silane coupling agent and 0-10 parts of solvent;

[0044] The B component includes: 15 to 50 parts of isocyanate curing agent.

[0045] In the present application, the isocyanate curing agent may be HDI trimer, such as TPA-100 purchased from Asahi Chemical, which has an NCO content of 23%.

[0046] In some specific embodiments, component A in the coating includes, by weight: 10 to 30 parts of the epoxy-modified oxazolidine, 10 to 30 parts of polyaspartic acid ester, 0.5 to 1 part of dispersant, 0 to 4 parts of anti-settling agent, 0.2 to 1 part of defoamer, 0.1 to 0.3 parts of anti-sagging agent, 10 to 30 parts of silicon micropowder, 0 to 5 parts of talc, 0 to 15 parts of titanium dioxide, 0 to 30 parts of micaceous iron powder, 0 to 10 parts of zinc phosphate, 0 to 20 parts of APW-1, 0 to 5 parts of molecular sieve, 0.1 to 0.5 parts of leveling agent, 0 to 2 parts of silane coupling agent and 0 to 10 parts of solvent.

[0047] The solvent in the A component described in the present application is used to dilute the A component to a suitable viscosity. In some specific embodiments, the solvent consists of xylene, butyl ester and PMA (propylene glycol monomethyl ether acetate).

[0048] In the present application, the coating can be used after the component A and the component B are mixed and cured before use, and the mass ratio of the component A and the component B when mixed is calculated as the secondary amine group equivalent in the component A: the isocyanate group equivalent in the component B = 1: (1.05-1.1). By controlling the mass ratio of the component A and the component B when mixed within the above range, the component A and the component B of the coating can be fully cross-linked during curing and forming, so that the density of the coating is better, thereby improving the adhesion between the coating and the substrate and the salt spray resistance of the coating.

[0049] In the present application, the preparation method of component A of the coating comprises: adding the polyaspartic acid ester, epoxy-modified oxazolidine, dispersant, anti-settling agent, defoaming agent and anti-sagging agent into a stirring kettle, and dispersing at high speed for 5 to 10 minutes; then, adding subsequent powders (fillers, coloring pigments, anti-rust pigments and / or molecular sieves) in sequence under medium-speed dispersion, dispersing at high speed to a fineness of ≤30 μm, and finally adding a leveling agent and a silane coupling agent, and adjusting to a suitable viscosity with a solvent to obtain component A.

[0050] The beneficial technical effect of the present application is as follows: the present application provides an epoxy-modified oxazolidine. After the construction of the epoxy-hybrid asparagine polyurea coating containing the epoxy-modified oxazolidine is completed, the coating absorbs moisture in the air to hydrolyze the epoxy-modified oxazolidine to release -NH and -OH, which participate in cross-linking and curing together with polyaspartic acid ester and isocyanate curing agent, thereby solving the problem that the cold-mixed epoxy resin in the prior art solution cannot participate in the asparagine polyurea film formation. At the same time, the density of the coating is higher through cross-linking and curing, thereby improving the adhesion between the coating and the substrate and the salt spray resistance. In addition, the prepared epoxy-modified oxazolidine greatly reduces the effect of molecular hydrogen bonds because the highly active secondary amine and hydroxyl groups are blocked. Compared with the epoxy-modified asparagine polyurea coating in the prior art solution, the coating of the present application has a lower viscosity, a longer application period, and can be cured at room temperature, and has good application prospects. DETAILED DESCRIPTION

[0051] In order to make the present application easier to understand, the present application will be further described in detail below in conjunction with the examples, which are merely illustrative and are not intended to limit the scope of application of the present application. The raw materials or components used in the present application can be obtained through commercial routes or conventional methods unless otherwise specified.

[0052] The polyaspartic acid ester used in the application example is polyaspartic acid ester F420, which has a secondary amine group equivalent of 277, a solid content of 98.2%, and a viscosity (25° C.) of 1300 cps.

[0053] Example 1: Preparation of epoxy-modified oxazolidine

[0054] Take a 1L four-necked glass flask, add 93g (1mol) of aniline, and under nitrogen protection, dropwise add 164.2g (1mol) of benzyl glycidyl ether, and control the dropping temperature to ≤50°C. After the dropping is completed, raise the temperature to 50°C and continue the reaction for 24h to obtain the β-amino alcohol 1 to be modified;

[0055] 90.4 g of isovaleraldehyde (1.05 mol) and 100 g of cyclohexane (water solvent) were added to the above-mentioned epoxy-amine modified β-amino alcohol 1, and the temperature was raised to 100°C for reflux dehydration. After the dehydration was completed, the excess isovaleraldehyde and cyclohexane were extracted by vacuum distillation to obtain epoxy-modified oxazolidine 1. The reaction formula is as follows:

[0056]

[0057] The primary amine compound-aniline and the epoxy compound-benzyl glycidyl ether used in the preparation process of the epoxy-modified oxazolidine 1 are both monofunctional compounds. In this case, a or b in the structure of the epoxy-modified oxazolidine prepared is 1, and R 1 For H, R 2 According to the molar ratio of the functional groups, the molar ratio of aniline, benzyl glycidyl ether and isovaleraldehyde added in the preparation process is 1:1:1.05.

[0058] The basic index data of the prepared epoxy-modified oxazolidine 1 are shown in Table 1.

[0059] Example 2: Preparation of epoxy-modified oxazolidine

[0060] Take a 1L four-necked glass flask, add 129g (1mol) of isooctylamine, and under nitrogen protection, dropwise add 196g (0.5mol) of E51 epoxy resin, and control the dropping temperature to ≤40°C. After the dropping is completed, heat to 40°C and continue the reaction for 24h to obtain the β-amino alcohol 2 to be modified;

[0061] 216 g of butanone (3 mol) and 100 g of cyclohexane were added to the above epoxy-amine modified β-amino alcohol 2, and the temperature was raised to 85° C. for reflux dehydration. After dehydration, the excess butanone and cyclohexane were extracted by vacuum distillation to obtain epoxy modified oxazolidine 2.

[0062] The structural formulas of β-amino alcohol 2 and epoxy-modified oxazolidine 2 are shown below:

[0063]

[0064] The primary amine compound - isooctylamine used in the preparation process of epoxy-modified oxazolidine 2 is a monofunctional compound, and the epoxy compound - E51 epoxy resin is a difunctional compound; the structure of the epoxy-modified oxazolidine obtained at this time is shown in formula (1), where a is 2, R 1 For H, R 2 According to the molar ratio of the functional groups, the molar ratio of isooctylamine, E51 epoxy resin and butanone added in the preparation process is 1:1:3.

[0065] The basic index data of the prepared epoxy-modified oxazolidine 2 are shown in Table 1.

[0066] Example 3: Preparation of epoxy-modified oxazolidine

[0067] Take a 1L four-necked glass flask and add 129g of isooctylamine (1 mol, NH 2 Equivalent weight 129), under nitrogen protection, 170 g of F170 phenolic epoxy resin (epoxy equivalent weight 170) was added dropwise, and the dropping temperature was controlled to be ≤ 60°C. After the dropping was completed, the temperature was raised to 90°C and the reaction was continued for 24 hours to obtain epoxy-amine modified β-amino alcohol 3;

[0068] 86 g of isovaleraldehyde (1 mol) and 100 g of cyclohexane were added to the above epoxy-amine modified β-amino alcohol 3, and the temperature was raised to 110° C. for reflux dehydration. After dehydration, the cyclohexane was extracted by vacuum distillation to obtain epoxy modified oxazolidine 3.

[0069] The primary amine compound - isooctylamine used in the preparation process of epoxy-modified oxazolidine 3 is a monofunctional compound, and the epoxy compound - F170 novolac epoxy resin is a mixed functional compound with an average functionality of 2.5; the epoxy-modified oxazolidine structure obtained at this time is shown in formula (1), where the average value of a in the structure is 2.5, and R 1 For H, R 2 According to the molar ratio of the functional groups, the molar ratio of isooctylamine, F170 phenolic epoxy resin and isovaleraldehyde added in the preparation process is 1:1:1.

[0070] The basic index data of the prepared epoxy-modified oxazolidine 3 are shown in Table 1.

[0071] Example 4: Preparation of epoxy-modified oxazolidine

[0072] Take a 1L four-necked glass flask, add 89g (0.5mol) of diethyltoluenediamine, and under nitrogen protection, dropwise add 388g (1mol) of NC513 cardanol-modified epoxy resin, and control the dropping temperature to ≤50°C. After the dropping is completed, heat to 70°C and continue the reaction for 24h to obtain epoxy-amine-modified β-amino alcohol 4;

[0073] 106 g of benzaldehyde (1 mol) and 100 g of cyclohexane were added to the above epoxy-amine modified β-amino alcohol 4, and the temperature was raised to 100° C. for reflux dehydration. After dehydration, the mixture was distilled under reduced pressure to extract the cyclohexane, thereby obtaining epoxy modified oxazolidine 4.

[0074] The primary amine compound - diethyltoluenediamine used in the preparation process of epoxy-modified oxazolidine 4 is a difunctional compound, and the epoxy compound - NC513 cardanol-modified epoxy resin is a monofunctional compound; the structure of the epoxy-modified oxazolidine obtained at this time is shown in formula (2), where b is 2, R 1 For H, R 2 According to the molar ratio of the functional groups, the molar ratio of diethyltoluenediamine, NC513 cardanol modified epoxy resin and benzaldehyde added in the preparation process is 1:1:1.

[0075] The basic index data of the prepared epoxy-modified oxazolidine 4 are shown in Table 1.

[0076] Example 5: Preparation of epoxy-modified oxazolidine

[0077] Take a 1L four-necked glass flask, add 105g (0.5mol) of 4,4'-diaminodicyclohexylmethane and 100g of toluene (water solvent), and under nitrogen protection, dropwise add 150g (1mol) of phenyl glycidyl ether, and control the dropping temperature to ≤50°C. After the dropping is completed, raise the temperature to 80°C and continue the reaction for 24h to obtain epoxy-amine-modified β-amino alcohol 5;

[0078] 86 g of isovaleraldehyde (1 mol) was added to the above epoxy-amine modified β-amino alcohol 5, and the temperature was raised to 120° C. for reflux dehydration. After the dehydration was completed, the dehydration solvent toluene was extracted and distilled under reduced pressure to obtain epoxy modified oxazolidine 5.

[0079] The primary amine compound - 4,4'-diaminodicyclohexylmethane used in the preparation process of epoxy-modified oxazolidine 5 is a difunctional compound, and the epoxy compound - phenyl glycidyl ether is a monofunctional compound; the epoxy-modified oxazolidine obtained at this time has a structural formula as shown in formula (2), where b is 2, R 1 For H, R2 According to the molar ratio of the functional groups, the molar ratio of 4,4'-diaminodicyclohexylmethane, phenyl glycidyl ether and isovaleraldehyde added in the preparation process is 1:1:1.

[0080] The basic index data of the prepared epoxy-modified oxazolidine 5 are shown in Table 1.

[0081] Comparative Examples 1-5

[0082] The difference between Comparative Examples 1-5 and Examples 1-5 is that in Comparative Examples 1-5, no corresponding aldehyde or ketone-blocked epoxy-amine-modified β-amino alcohols 1-5 are added.

[0083] The basic index data of the prepared epoxy-amine modified β-amino alcohols 1-5 are shown in Table 1 respectively.

[0084] Comparative Example 6

[0085] Take a 1L four-necked glass flask, add 105g (0.5mol) of 4,4'-diaminodicyclohexylmethane, and under nitrogen protection, dropwise add 75g (0.5mol) of phenyl glycidyl ether, and control the dropping temperature to ≤50°C. After the dropping is completed, raise the temperature to 80°C and continue the reaction for 24h to obtain epoxy-amine-modified β-amino alcohol 6;

[0086] 86 g of diethyl maleate was added dropwise to the epoxy-amine modified β-amino alcohol 6. After the addition was completed, the temperature was raised to 90° C. and kept for 96 h to obtain epoxy modified polyaspartic acid ester 1.

[0087] The basic index data of the prepared epoxy-modified polyaspartic acid ester 1 are shown in Table 1.

[0088] Table 1

[0089]

[0090] The secondary amine equivalent of the epoxy-modified oxazolidine prepared by Example 1-5 in Table 1 refers to the secondary amine equivalent generated after its hydrolysis. As can be seen from Table 1, the viscosity of the epoxy-modified oxazolidine prepared by the present application is moderate, and the use performance is good. And the epoxy-amine-modified β-amino alcohol 1-5 prepared in Comparative Examples 1-5 is due to the absence of secondary amine (-NH) and hydroxyl (-OH) with high activity, resulting in the molecular hydrogen bonding effect being strong, the viscosity of the coating prepared is too high; and unblocked-NH and -OH are highly active, and the reaction speed with isocyanate curing agent is too fast after being prepared into coating, which will affect the use performance of the coating prepared later, greatly shorten the operation time of coating, and be unfavorable for construction; The epoxy-modified polyaspartic acid ester prepared by Comparative Example 6 also has highly active secondary amine and hydroxyl, and then causes the viscosity of epoxy-modified polyaspartic acid ester to be too large, and the reaction speed with isocyanate curing agent is too fast after being prepared into coating, which will also affect the use performance of the coating prepared later, greatly shorten the operation time of coating, and be unfavorable for construction.

[0091] Application Example 1: Preparation of epoxy hybrid aspartame polyurea coating

[0092] Preparation of component A: According to the raw material ratio shown in Table 2, first add polyaspartic acid resin, epoxy modified oxazolidine, dispersant, anti-settling agent, defoamer and anti-sagging agent, and stir and disperse at 1500rpm for 10 minutes; then add subsequent powders (filler, coloring pigment, anti-rust pigment) in sequence at a stirring speed of 800rpm, stir and disperse at a speed of 1500rpm to a fineness of ≤30μm, add leveling agent and silane coupling agent, and finally adjust to a suitable viscosity with solvent to obtain component A. The solvent in the preparation process is composed of xylene, butyl ester and PMA, and the volume ratio of xylene: butyl ester: PMA is 4:4:2.

[0093] Component B is HDI trimer, specifically Asahi Kasei TPA-100, in which the NCO content is 23%.

[0094] The component A and the component B are mixed in a mass ratio of 1:1.05 to obtain an epoxy hybrid aspart polyurea coating.

[0095] Application Example 2-5: Preparation of epoxy hybrid aspartame polyurea coating

[0096] The preparation process is the same as that of Application Example 1, except that the raw material ratio of component A is different. The raw material ratio of component A in Application Examples 2-5 is specifically shown in Table 2.

[0097] Comparative Application Examples 1-8

[0098] The preparation process is the same as that of Application Example 1, except that the raw material ratio of component A is different. The raw material ratio of component A in Comparative Application Examples 1-8 is specifically shown in Table 3.

[0099] Table 2

[0100]

[0101]

[0102] Table 3

[0103]

[0104]

[0105] Test Example 1

[0106] The coatings prepared in the corresponding application examples 1-5 and comparative application examples 1-8 were tested for performance, and the test indicators included adhesion, pull-out adhesion, applicable period, actual drying time, pencil hardness and salt spray resistance. Specifically, the coating was applied with a hand spray gun, and the substrate was a sandblasted steel plate. The average thickness of one application was 70 μm, and then it was cured for 7 days under standard curing conditions. Among them, the test method for applicable period refers to GB / T31416-2015, the test method for actual drying time refers to GB / T1728-1989, the test method for adhesion refers to GB / T9286-1998, the test method for pull-out adhesion refers to ASTM D4541, the test method for pencil hardness refers to GB / T6739-2006, and the test method for salt spray resistance refers to GB / T1771-2007. The specific test results are shown in Table 4.

[0107] Table 4

[0108]

[0109] From the test results of application examples 1-5 and comparative application examples 6-7 in Table 4, it can be seen that the salt spray resistance and adhesion to the substrate of the epoxy hybrid asparagine polyurea coating formed after adding the epoxy-modified oxazolidine prepared in this application are significantly improved, and the coating has a longer application period, which prolongs the operation time of the coating and is more conducive to construction. At the same time, the coating can be cured at room temperature and is easy to use. Application comparative example 6 is the cold-mixed epoxy resin solution mentioned in the prior art content, and application comparative example 7 is the asparagine polyurea solution. The comparison of the test results of application comparative example 6 and application comparative example 7 shows that the cold-mixed epoxy resin does not participate in film formation, which is manifested as prolonged actual drying time, reduced hardness, and poor salt spray resistance.

[0110] From the test results of comparative examples 1-5 and 8 in Table 4, it can be seen that the epoxy-amine modified β-amino alcohols 1-5 prepared in comparative examples 1-5 and the epoxy modified polyaspartic acid ester prepared in comparative example 6 have strong molecular hydrogen bonding due to the presence of highly active secondary amine groups and hydroxyl groups, and the viscosity is too high. After being prepared into coatings, the reaction speed with isocyanate curing agent is too fast, and gel appears within a few seconds. Ordinary spraying equipment cannot be used for construction, which seriously affects the applicable period of the coatings. Among them, the coatings prepared by comparative examples 1-3 and 5 have no applicable period, resulting in the failure of coating construction, so the adhesion, pull-out adhesion, actual drying time, pencil hardness and salt spray resistance of the coatings cannot be tested.

[0111] It should be noted that the embodiments described above are only used to explain the present application and do not constitute any limitation to the present application. The present application is described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present application may be modified as specified within the scope of the claims of the present application, and the present invention may be revised without departing from the scope and spirit of the present application. Although the present application described therein relates to specific methods, materials and embodiments, it does not mean that the present application is limited to the specific examples disclosed therein. On the contrary, the present application can be extended to all other methods and applications with the same functions.

Claims

1. An epoxy-modified oxazolidine, It is characterized in that The epoxy-modified oxazolidine is prepared by reacting the primary amine group of a primary amine compound with the epoxy group of an epoxy compound through an epoxy ring-opening reaction, followed by dehydration condensation with a carbonyl-containing compound. and at least one of the primary amine compound and the epoxy compound is a monofunctional compound; When the primary amine compound is a monofunctional compound, the structural formula of the epoxy-modified oxazolidine is as shown in formula (1); When the epoxy compound is a monofunctional compound, the structural formula of the epoxy-modified oxazolidine is as shown in formula (2); Among them, X in formula (1) 1 For the primary amine compound to remove -NH 2 The residue remaining after the group, Y 1 is the residue remaining after removing a -CH(O)CH epoxy groups from the epoxy compound; in formula (2), X 2 For the primary amine compound, remove b -NH 2 The residue remaining after the group, Y 2 is the residue remaining after removing the -CH(O)CH epoxy group from the epoxy compound; R in formula (1) and formula (2) 1 and R 2 Each is independently selected from any one of H, C1-C18 alkyl and C6-C18 aralkyl; said a and b are each independently selected from any integer from 1 to 6; The primary amine compound is selected from at least one of diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, aniline, m-phenylenediamine, 1,3-cyclohexyldimethylamine, γ-aminopropyltriethoxysilane, 1,3-propylenediamine, pentamethylenediamine, 2-methyl-1,5-pentamethylenediamine, cyclohexyldiamine, methylcyclohexyldiamine, 2-amino-2-methyl-1-propanol, diethyltoluenediamine, dimethylthiotoluenediamine, 4-phenylbutylamine, cyclohexylamine, isooctylamine, 2,4,4-trimethyl-2-pentylamine and oleylamine; the epoxy The compound is selected from at least one of E44 epoxy resin, E51 epoxy resin, F44 epoxy resin, F51 epoxy resin, NC513 epoxy resin, NC514 epoxy resin, NC547 epoxy resin, phenyl glycidyl ether, benzyl glycidyl ether, o-tolyl glycidyl ether, triglycidyl isocyanurate, N,N,N',N'-tetracyclyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetra(oxiranylmethyl)-1,3-phenylenediamine, resorcinol diglycidyl ether, diglycidyl phthalate, diglycidyl hexahydrophthalate, cyclohexene oxide, epoxy soybean oil, tert-butyl glycidyl ether and γ-glycidyloxypropyltrimethoxysilane; The carbonyl-containing compound is at least one selected from benzaldehyde, phenylacetaldehyde, n-butyraldehyde, isobutyraldehyde, isovaleraldehyde, 2,2-dimethyl-3-lauroyloxy-propionaldehyde, butanone, methyl isobutyl ketone, methyl acetoacetate and ethyl acetoacetate; According to the molar ratio of their respective functional groups, the molar ratio of the primary amine compound, the epoxy compound and the carbonyl-containing compound is 1:(0.05-1):(0.05-4); wherein the functional group of the primary amine compound is -NH 2 , the functional group of the epoxy compound is -CH(O)CH, and the functional group of the carbonyl-containing compound is -C=O.

2. The epoxy-modified oxazolidine according to claim 1, It is characterized in that The a is 1, 2, 3 or 4, and the b is 1, 2 or 3.

3. A method for preparing the epoxy-modified oxazolidine according to claim 1 or 2, It is characterized in that The method comprises the following steps: S1, under the protection of an inert gas, mixing the epoxy compound and the primary amine compound and performing an epoxy ring-opening reaction to obtain a β-amino alcohol to be modified; S2, mixing the β-amino alcohol to be modified with the carbonyl-containing compound, performing dehydration condensation, and adding a water-containing solvent for reflux dehydration; S3, after the dehydration is completed, removing the excess carbonyl-containing compound to obtain the epoxy-modified oxazolidine.

4. An epoxy hybrid aspartic polyurea coating, It is characterized in that The coating comprises component A and component B, wherein component A comprises the epoxy-modified oxazolidine as claimed in claim 1 or 2 or the epoxy-modified oxazolidine prepared by the method of claim 3, and component B is an isocyanate curing agent; The mass ratio of the component A and the component B when mixed is calculated as follows: the secondary amine group equivalent in the component A: the isocyanate group equivalent in the component B = 1: (1.05-1.1).

5. The coating according to claim 4, It is characterized in that The component A also includes polyaspartic acid ester, and at least one of a dispersant, an anti-settling agent, a defoamer, an anti-sagging agent, a filler, a coloring pigment, an anti-rust pigment, a molecular sieve, a leveling agent, a silane coupling agent and a solvent.

6. The coating according to claim 5, It is characterized in that In parts by weight, the component A and the component B in the coating respectively include the following ingredients: The component A comprises: 10-30 parts of the epoxy-modified oxazolidine, 10-30 parts of polyaspartic acid ester, 0.5-1 parts of dispersant, 0-4 parts of anti-settling agent, 0.2-1 parts of defoamer, 0.1-0.3 parts of anti-sagging agent, 10-35 parts of filler, 0-15 parts of coloring pigment, 5-20 parts of anti-rust pigment, 0-5 parts of molecular sieve, 0.1-0.5 parts of leveling agent, 0-2 parts of silane coupling agent and 0-10 parts of solvent; The B component includes: an isocyanate curing agent.

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