CN113201087B

CN113201087B - Hydroxyacrylic dispersions, process for their preparation and two-component polyurethane paints

Info

Publication number: CN113201087B
Application number: CN202011308986.0A
Authority: CN
Inventors: 周国强; 刘艳; 朱小勇
Original assignee: Liangu New Material Technology Guangzhou Co ltd
Current assignee: Huangshan Liangu New Material Technology Co ltd
Priority date: 2020-11-20
Filing date: 2020-11-20
Publication date: 2022-08-19
Anticipated expiration: 2040-11-20
Also published as: CN113201087A

Abstract

The invention relates to the technical field of acrylic acid materials, in particular to a hydroxyl acrylic acid dispersoid, a preparation method thereof and a bi-component polyurethane paint. The hydroxyl acrylic acid dispersion is mainly prepared from the following components in parts by weight: 6-10 parts of a film-forming assistant, 36-52 parts of a monomer, 1.5-2 parts of an initiator, 1.4-2.5 parts of an amine compound and water; the monomer comprises unsaturated monomer containing amine urea; the mass of the unsaturated monomer containing the amino urea is 4.5-22.8% of the mass of the monomer; the amine compound is a primary amine compound. The hydroxyacrylic dispersions of the invention have excellent initial water resistance.

Description

Hydroxyacrylic dispersions, process for their preparation and two-component polyurethane paints

Technical Field

The invention relates to the technical field of acrylic acid materials, in particular to a hydroxyl acrylic acid dispersoid, a preparation method thereof and a two-component polyurethane paint.

Background

The hydroxyl acrylic acid dispersoid has better luster and more excellent performance, and is widely applied to a plurality of fields of metal, woodware, industry and the like. For aqueous resins, there is a need for both good aqueous dispersions and good water resistance. Under the drying condition, the hydroxyl acrylic acid dispersoid of both single component and double component is dried and crosslinked quickly, so that the hydroxyl acrylic acid dispersoid has better initial water-resistant effect under the drying condition at present, but the drying condition obviously cannot meet the requirement for small enterprises and enterprises without baking condition. However, the initial water resistance of the hydroxyl acrylic acid dispersion in the prior art under the self-drying condition is relatively poor, so that how to obtain better initial water resistance under the self-drying condition is very important.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The first purpose of the invention is to provide a hydroxy acrylic acid dispersion to solve the technical problem of poor initial water resistance of the hydroxy acrylic acid dispersion under the self-drying condition in the prior art.

A second object of the present invention is to provide a method for producing a hydroxyacrylic dispersion.

A third object of the present invention is to provide a two-component polyurethane paint prepared using a hydroxyacrylic dispersion.

A fourth object of the present invention is to provide a method for improving the initial water resistance of a hydroxyacrylic dispersion, which can rapidly improve the initial water resistance of a film-forming material under self-drying and baking conditions.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

the hydroxyl acrylic acid dispersion is mainly prepared from the following components in parts by weight:

6-10 parts of a film-forming assistant, 36-52 parts of a monomer, 1.5-2 parts of an initiator, 1.4-2.5 parts of an amine compound and water;

the monomer comprises the following components in parts by weight:

2-10 parts of unsaturated monomer containing aminourea, 1.2-1.4 parts of acrylic monomer, 8.9-9.1 parts of (methyl) acrylic acid hydroxyl ester, 15.5-23 parts of non-functional (methyl) acrylic ester and 8.4-8.5 parts of non-acrylic alkenyl monomer;

the mass of the unsaturated monomer containing the aminourea is 4.5-22.8% of that of the monomer;

the amine compound is a primary amine compound.

In a specific embodiment of the invention, the unsaturated monomer containing an aminourea is methacrylamide ethylethylene urea.

In a particular embodiment of the invention, the monomers further comprise acrylic monomers and hydroxy (meth) acrylates. Further, the acrylic monomer comprises any one or two of acrylic acid and methacrylic acid; the hydroxy (meth) acrylate comprises hydroxyethyl (meth) acrylate.

In a specific embodiment of the present invention, the primary amine compound comprises any one or more of ethanolamine, AMP-95, m-xylylenediamine, methylamine, and ethylamine.

In a specific embodiment of the invention, the dispersion comprises more than 50 mol% of acid groups neutralized by the amine compound. By more than 50 mol% is meant that in the dispersion, the acid groups (which have actually reacted and are present in the form of neutralization by the amine compound) neutralized by the amine compound account for more than 50% of all acid groups in the system before reaction with the amine compound, on a molar basis.

In a particular embodiment of the invention, the monomer further comprises a non-functional (meth) acrylate. Further, the non-functional (meth) acrylate includes any one or more of methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and t-butyl (meth) acrylate.

In a particular embodiment of the invention, the monomers further comprise non-acrylic alkenyl monomers. Further, the non-acrylic alkenyl monomer includes any one or more of butylene glycol, styrene, methyl styrene and sodium styrene sulfonate.

In a specific embodiment of the invention, the monomers include aminourea-containing unsaturated monomers, acrylic monomers, hydroxy (meth) acrylates, non-functional (meth) acrylates, and non-acrylic alkenyl monomers.

In a particular embodiment of the invention, the coalescent includes any one or more of an alcohol coalescent, a benzene coalescent, and an alcohol ether coalescent. Further, the film forming auxiliary agent comprises any one or more of ethylene glycol butyl ether, propylene glycol methyl ether acetate and diethylene glycol butyl ether.

In a specific embodiment of the present invention, the initiator may be an initiator capable of initiating polymerization of the monomer. Further, the initiator is an oil soluble initiator, such as a t-butyl peroxide initiator.

In the embodiment of the invention, the amount of water is 43-45.5 parts.

The invention also provides a preparation method of the hydroxyl acrylic acid dispersion, which comprises the following steps:

dropwise adding a mixture of a monomer and a part of initiator into the preheated film-forming assistant, adding the rest of initiator after dropwise adding, and preserving heat at 140-450 ℃ for 1.5-2.5 h; and cooling to 80-85 ℃, adding the amine compound, stirring uniformly, adding water, and stirring and dispersing uniformly.

In a specific embodiment of the present invention, the dropping comprises: 80-85% of the mixture is dripped within 3.5-4.5 h, and then 15-20% of the mixture is dripped within 1-3 h.

In a specific embodiment of the invention, the preheating temperature is 140-145 ℃.

In a specific embodiment of the invention, the stirring and dispersing time is 1.5-2.5 h.

The invention also provides a two-component polyurethane paint comprising any one of the above-described hydroxyacrylic dispersions.

In a particular embodiment of the invention, the two-component polyurethane paint further comprises an isocyanate-based curing agent.

The invention also provides a method for improving the initial water resistance of a hydroxyacrylic dispersion, comprising: regulating and controlling the use amount of each component in the dispersion to ensure that the copolymer of the dispersion comprises the following components in parts by weight:

the monomer comprises the following components in parts by weight: 2-10 parts of unsaturated monomer containing amino urea, 1.2-1.4 parts of acrylic monomer, 8.9-9.1 parts of hydroxyl (meth) acrylate, 15.5-23 parts of non-functional (meth) acrylate and 8.4-8.5 parts of non-acrylic alkenyl monomer;

the amine compound is a primary amine compound;

the dispersion also comprises more than 50 mol% of acid groups neutralized by the amine compound. .

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

(1) the amino urea structure is introduced into the hydroxyl acrylic acid dispersoid, so that the wet adhesion to a substrate can be improved; in addition, the introduction of amine groups in the amino urea can further improve the stability, the dispersibility and the wettability to pigments, fillers and the like, and can further react to form urea groups after being mixed with an isocyanate curing agent to improve the initial water resistance and the like;

(2) in the hydroxyl acrylic acid dispersion, 50 mol% of acid groups exist in a primary amine neutralization mode, primary amine partially forms secondary amine groups, the reaction speed of the secondary amine groups and an isocyanate curing agent is much higher than that of hydroxyl, and the secondary amine groups in the dispersion react with isocyanate to quickly improve the crosslinking speed on one hand and react with the isocyanate to form carbamido on the other hand, so that the initial water resistance of the hydroxyl acrylic acid dispersion is further improved under the synergistic effect of the two aspects;

(3) the hydroxyl acrylic acid dispersoid has wide application range, is suitable for drying and self-drying, and the formed paint film has excellent initial water resistance and excellent wet adhesion, and the paint film has better performance than most of film-forming resins after being completely dried, and has low cost.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a chart comparing the initial water resistance of paint films obtained in example 2 of the present invention and comparative example 4; in which (a) corresponds to the paint film obtained in example 2 and (b) corresponds to the paint film obtained in comparative example 4.

Detailed Description

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are some, not all, of the embodiments of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The hydroxyl acrylic acid dispersion is mainly prepared from the following components in percentage by mass:

the monomer comprises unsaturated monomer containing amine urea; the mass of the unsaturated monomer containing the aminourea is 4.5-22.8% of that of the monomer;

the amine compound is a primary amine compound.

The hydroxyl acrylic acid dispersoid introduces an aminourea structure, improves the wet adhesion to a substrate, and simultaneously can improve the stability and the dispersibility of resin and the wettability to pigments, fillers and the like; and the amino urea structure can further react with isocyanate in the curing process to form carbamido, so that the crosslinking density is improved, and the carbamido structure is introduced, so that the water resistance and other properties are improved in many aspects.

As in various embodiments, the coalescents can be used in amounts of 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, 10 parts, and the like; the monomers may be used in amounts of 36 parts, 37 parts, 38 parts, 39 parts, 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 parts, 49 parts, 50 parts, 51 parts, 52 parts, and the like; the amine compound may be used in an amount of 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, 2.5 parts, etc.

As in various embodiments, the mass percent of the amine-based urea-containing unsaturated monomer in the monomers can be 4.5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 22.8%, and so forth.

In a preferred embodiment of the present invention, the hydroxyl acrylic dispersion is prepared by mainly using the following components in parts by weight:

8-10 parts of a film-forming assistant, 40-45 parts of a monomer, 1.5-2 parts of an initiator, 1.4-1.6 parts of an amine compound and water.

In a specific embodiment of the invention, the amine-urea containing unsaturated monomer comprises ureido methacrylate and/or methacrylamidoethylethylene urea.

In a specific embodiment of the present invention, the primary amine compound comprises any one or more of ethanolamine, AMP-95, m-xylylenediamine, methylamine and ethylamine.

According to the invention, by adopting the primary amine compound instead of the secondary amine compound, the primary amine compound and the acidic groups in the copolymer obtained by polymerization can be subjected to neutralization reaction to form secondary amine groups, and the secondary amine groups can be quickly reacted with isocyanate, so that the crosslinking speed is quickly increased, urea groups are formed by reaction, and the initial water resistance of the dispersion is improved.

The invention adopts the raw materials with specific types and dosage, regulates and controls the number of acid groups neutralized by amine compounds in the dispersion, and adjusts the reaction speed with isocyanate curing agent and the cross-linking structure obtained after the reaction, thereby improving the initial water resistance.

In a specific embodiment of the present invention, the monomer comprises the following components in parts by weight:

2-10 parts of unsaturated monomer containing amine-based urea, 1.2-1.4 parts of acrylic monomer, 8.9-9.1 parts of hydroxyl (meth) acrylate, 15.5-23 parts of non-functional (meth) acrylate and 8.4-8.5 parts of non-acrylic alkenyl monomer.

2-10 parts of unsaturated monomer containing amine urea, 1.25 parts of acrylic monomer, 8.9 parts of hydroxyl (meth) acrylate, 15.5-23 parts of non-functional (meth) acrylate and 8.4 parts of non-acrylic alkenyl monomer.

Further, the monomer comprises the following components in parts by weight:

2-10 parts of unsaturated monomer containing aminourea, 1.25 parts of acrylic acid, 8.9 parts of hydroxyethyl methacrylate, 7.5-12.5 parts of methyl methacrylate, 8-10.5 parts of butyl acrylate and 8.4 parts of styrene.

By adopting the monomer combination mode, the prepared dispersion can achieve both the initial water resistance and the paint film performance.

In particular embodiments of the present invention, the coalescents include any one or more of alcohol coalescents, benzene coalescents, and alcohol ether coalescents. Further, the film forming auxiliary agent comprises any one or more of ethylene glycol butyl ether, propylene glycol methyl ether acetate and diethylene glycol butyl ether.

In a specific embodiment of the present invention, the initiator may be an initiator capable of initiating polymerization of the monomer.

As in practice, the initiator is an oil soluble initiator, such as but not limited to a t-butyl peroxide initiator.

In the embodiment of the invention, the amount of the water is 43-45.5 parts. As in various embodiments, the water may be used in amounts of 43 parts, 43.5 parts, 44 parts, 44.5 parts, 45 parts, 45.5 parts, and the like. In practice, the water may be deionized water.

In a specific embodiment of the present invention, the partial initiator means 70% to 80% of all initiators.

In a specific embodiment of the present invention, the manner of adding water includes: the water is added dropwise within 1-1.5 h.

In a specific embodiment of the invention, the two-component polyurethane paint further comprises an isocyanate curing agent, preferably any one or a combination of HDI trimer, MDI, TDI and IPDA.

In one embodiment of the present invention, the molar ratio of isocyanate groups to hydroxyl groups in the raw materials of the two-component polyurethane paint is (1.3 to 1.4): 1.

In practical operation, the raw materials of the two-component polyurethane paint also comprise: wetting agent, flatting agent, thickening agent, film forming assistant and water.

The invention also provides a method for improving the initial water resistance of a hydroxyacrylic dispersion, comprising: the amount of each component in the dispersion is regulated so that the copolymer of the dispersion comprises 4.5-22.8% of structural units of unsaturated monomer containing aminourea by mass percentage.

In a specific embodiment of the present invention, the method further comprises: regulating the using amount of each component in the dispersion to enable the dispersion to comprise more than 50 mol% of acid groups neutralized by amine compounds.

Wherein the amine compound is a primary amine compound.

Examples 1 to 3

The raw material information used in the preparation of the hydroxyacrylic acid dispersions of examples 1 to 3 is shown in tables 1 to 2, specifically as follows:

TABLE 1 types and amounts of raw materials for different examples

TABLE 2 types and amounts of monomers used in different examples

The method for producing the acrylic dispersion of examples 1 to 3, comprising the steps of:

(1) placing the film-forming auxiliary agent in a four-neck flask, and heating to 140-145 ℃;

(2) uniformly stirring and mixing the monomer and 80% of initiator to obtain a mixture;

(3) dropwise adding the mixture obtained in the step (2) into the film-forming aid subjected to temperature rise treatment in the step (1), wherein the dropwise adding of the mixture is completed within 4 hours, and the dropwise adding of the rest 20% is completed within 1.5 hours; then supplementing the rest of initiator, and keeping the temperature at 140-145 ℃ for 2 h;

(4) and cooling to 80 ℃, adding an amine compound, uniformly stirring, dropwise adding deionized water within 1h, and stirring and dispersing for 2h to obtain the hydroxyl acrylic acid dispersoid.

Example 4

This example refers to the preparation of example 2, with the only difference that: the amine compound is used in different amounts. The amine compound of this example was 0.8g of ethanolamine.

Comparative examples 1 to 2

The preparation process of the hydroxyacrylic acid dispersions of comparative examples 1 to 2 is as follows, referring to example 1, except that the raw materials used are different, and the raw material information of comparative examples 1 to 2 is shown in tables 3 to 4:

TABLE 3 types and amounts of raw materials for various comparative examples

TABLE 4 kinds and amounts of monomers used in various comparative examples

Comparative examples 3 to 5

The production processes of the hydroxyacrylic acid dispersions of comparative examples 3 to 5 were as described in example 1, except that the raw materials used were different, and the raw material information of comparative examples 3 to 5 is shown in tables 5 to 6, specifically as follows:

TABLE 5 types and amounts of raw materials for various comparative examples

TABLE 6 kinds and amounts of monomers used in various comparative examples

Comparative example 6

Comparative example 6 the preparation of reference example 2 was followed with the following differences: the type and amount of the monomer are different. The monomers of comparative example 6 included: 1g of methacrylamide ethyl ethylene urea, 1.25g of acrylic acid, 13.5g of methyl methacrylate, 10.5g of butyl acrylate, 8.9 parts of hydroxyethyl methacrylate and 8.4 parts of styrene.

Comparative example 7

Comparative example 7 the preparation of reference example 2 was carried out with the following differences: the amine compound is dimethylethanolamine 2.3 g.

Experimental example 1

To illustrate the properties of the hydroxyacrylic dispersions of the different examples and comparative examples of the present invention by comparison, the hydroxyacrylic dispersions obtained in the respective examples and comparative examples were tested for their properties, and the results are shown in Table 7.

The test method of each test item is as follows:

solid content: according to the method for measuring the solid content of the GB1725-79 coating (160 ℃/30 min);

stability: carrying out hot storage at 50 ℃ for 7 days, and observing whether the resin is layered or not;

drying speed: after the coating is sprayed on a tin plate, the required time is indicated to be press-dried under the condition of normal temperature;

gloss: self-drying the paint film for 16 hours at normal temperature, and measuring the gloss of the paint film by using a gloss meter;

initial hardness: the paint film which is self-dried for 16 hours at normal temperature is measured according to the method for measuring the hardness of the paint film by the GB/T6739-2006 pencil method;

initial water resistance: and (3) immersing the paint film self-dried for 16 hours at normal temperature into normal temperature water to observe the change of the paint film, wherein the days corresponding to the occurrence of visible bubbles are provided.

Wherein, the solid content and the stability are tested on the hydroxy acrylic acid dispersoid; drying speed, gloss, initial hardness, initial water resistance are tests on the paint film.

TABLE 7 results of the Performance tests of different hydroxyacrylic dispersions and paint films

From the above test results, it can be seen that the hydroxyacrylic dispersions of the invention produce paints having excellent initial water resistance, having better hardness and better initial water resistance.

Wherein the preparation process of the paint film comprises the following steps: mainly comprises hydroxyl acrylic acid dispersoid and a waterborne isocyanate curing agent which are compounded for use. According to the solid content and the hydroxyl content of the dispersion, an isocyanate curing agent (HDI trimer) is added according to the molar ratio of isocyanate group (NCO) to hydroxyl group (OH) of 1.3-1.4: 1, a conventional auxiliary agent is added, after mixing and stirring, water is added to adjust the viscosity (25-35 s, 25 ℃ and 4 cups) suitable for spray painting, the mixture is sprayed on a tin plate, and the mixture is dried for 16h at normal temperature and then tested, wherein the thickness of a paint film is 23 +/-2 mu m.

The hydroxy acrylate dispersions of the examples and comparative examples were prepared in such a way that the NCO to OH molar ratio was the same, the type and amount of auxiliaries were the same and the viscosity adjusted by adding water was the same. The specific paint film composition formulations are shown in Table 8.

TABLE 8 paint film Primary formulation

The name of the raw material is (g) the hydroxyl acrylic dispersion 70, the wetting agent is 0.2, the flatting agent is 0.2, the thickening agent is 0.8, the coalescing agent is 0.8, and the deionized water is properly added to enable the viscosity to reach 25-35 s (25 ℃, coating-4 cups) according to the NCO/OH (1.3-1.4)/1 ratio of the isocyanate curing agent

FIG. 1 is a graph showing the initial water resistance of paint films prepared from the hydroxyacrylic acid dispersions of example 2 of the present invention and comparative example 4 by room temperature self-drying for 16 hours when they are immersed in room temperature water for 5 days under the same conditions. While (a) in FIG. 1 shows the paint film obtained from the hydroxyacrylic dispersion of example 2 and (b) in FIG. 1 shows the paint film obtained from the hydroxyacrylic dispersion of comparative example 4, the preparation of the paint films of both cases was carried out by referring to the preparation process of the paint film described above, and it can be seen from FIG. 1 that the paint film obtained from comparative example 4 exhibited significant blisters at 5 days, while the paint film obtained from example 2 showed no significant change.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. The hydroxyl acrylic acid dispersoid is characterized by mainly comprising the following components in parts by weight:

the mass of the unsaturated monomer containing the amino urea is 4.5-22.8% of the mass of the monomer;

the amine compound is a primary amine compound;

the dispersion also comprises more than 50 mol% of acid groups neutralized by the amine compound.

2. The hydroxyacrylic acid dispersion according to claim 1, characterized in that the unsaturated monomer containing an aminourea is methacrylamidoethylethyleneurea.

3. The hydroxyacrylic dispersion according to claim 1, characterized in that said monomers further comprise acrylic monomers and hydroxy (meth) acrylates;

the acrylic monomer comprises any one or two of acrylic acid and methacrylic acid;

the hydroxy (meth) acrylate comprises hydroxyethyl (meth) acrylate.

4. The hydroxyacrylic acid dispersion according to claim 3, characterized in that the primary amine-based compound comprises any one or more of ethanolamine, AMP-95, m-xylylenediamine, methylamine and ethylamine.

5. The hydroxyacrylic dispersion of claim 1, characterized in that the monomers further comprise non-acrylic alkenyl monomers.

6. The method for producing a dispersion of a hydroxyacrylic acid as claimed in any of claims 1 to 5, characterized by comprising the steps of:

7. Two-component polyurethane paint, characterized in that it comprises a hydroxyacrylic dispersion according to any one of claims 1 to 5; also comprises an isocyanate curing agent.

8. A method for improving the initial water resistance of a hydroxyacrylic dispersion, characterized in that the hydroxyacrylic dispersion is any one of the hydroxyacrylic dispersions according to any one of claims 1 to 5; and the method further comprises: regulating and controlling the use amount of each component in the dispersion to ensure that the copolymer of the dispersion comprises the following components in parts by weight:

the monomer comprises the following components in parts by weight: 2-10 parts of unsaturated monomer containing aminourea, 1.2-1.4 parts of acrylic monomer, 8.9-9.1 parts of (methyl) acrylic acid hydroxyl ester, 15.5-23 parts of non-functional (methyl) acrylic ester and 8.4-8.5 parts of non-acrylic alkenyl monomer;

the amine compound is a primary amine compound;