CN110922874A

CN110922874A - Water-based acrylic polyurethane amino baking pearlescent paint and preparation method thereof

Info

Publication number: CN110922874A
Application number: CN201911125088.9A
Authority: CN
Inventors: 陈卓; 陈剑华; 王建川
Original assignee: Ji Tai Chemical Inc Guangzhou
Current assignee: Ji Tai Chemical Inc Guangzhou
Priority date: 2019-11-18
Filing date: 2019-11-18
Publication date: 2020-03-27
Anticipated expiration: 2039-11-18
Also published as: CN110922874B

Abstract

The invention discloses a waterborne acrylic polyurethane amino baking pearlescent paint and a preparation method thereof. The water-based acrylic polyurethane amino baking pearlescent paint consists of the following components: the coating comprises a hydroxyl acrylic acid dispersoid, water-based amino resin, a pH regulator, a cosolvent, a blocked isocyanate curing agent, pearl powder, a defoaming agent, a dispersing agent, a wetting agent, water, a pearl powder directional arrangement agent and a thickening agent; wherein the blocked isocyanate curing agent contains an aliphatic chain segment, an isocyanurate ring and an aromatic ring group. Also discloses a preparation method of the water-based pearlescent paint. The waterborne pearlescent paint disclosed by the invention is low in VOC content, excellent in environmental protection performance, high in crosslinking density of a paint film, full in paint film, high in glossiness, high in hardness, good in mechanical property and excellent in adhesive force. The water-based pearlescent paint has good directional arrangement effect of the pearlescent powder and excellent pearlescent effect, and is suitable for mechanical equipment. Meanwhile, the paint is a single component, so that the paint is convenient to construct, stable in performance and wide in application prospect.

Description

Water-based acrylic polyurethane amino baking pearlescent paint and preparation method thereof

Technical Field

The invention relates to the technical field of coatings, in particular to a water-based acrylic polyurethane amino baking pearlescent paint and a preparation method thereof.

Background

The mica pearlescent pigment is added into the paint, which can generate gorgeous and soft luster and fantasy color, so that the paint looks like pearly and shines, and attracts the attention of people. The pearlescent pigment is transparent metal oxide with high refractive index coated on the surface of transparent mica sheet, is exposed in natural environment, and can generate beautiful and elegant hue and luster after being refracted and reflected by sunlight.

The traditional oil paint has the defects of high VOC content, heavy pollution, serious pungent smell, serious influence on physical and psychological health of workers and people by harmful substances such as benzene substances, formaldehyde and the like contained in the paint, and the like. Compared with the traditional solvent-based coating, the water-based amino baking paint has slightly low glossiness, and slightly weak resistance and mechanical properties of a paint film. In addition, compared with solvent-based paint, the directional arrangement of the pearl powder of the water-based pearlescent paint is difficult.

The prior preparation process of the pearlescent pigment has the following technical problems: agglomerating the pearlescent pigment and blocking the gun head; the atomization effect of the pearlescent paint is poor, the sprayed paint mist is not uniform, and the covering power is poor; hammer marks or stripes are easy to appear on a paint film; the paint film has white spots or pits.

Therefore, the existing water-based pearlescent baking paint still has a plurality of defects and problems to be solved, and how to provide the water-based pearlescent baking paint with better comprehensive performance becomes a technical problem which is always overcome by the technical personnel in the field.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention aims to prepare the aqueous pearlescent baking paint with better pearlescent powder arrangement effect, higher hardness, better workability, safety, environmental protection requirement conformity, excellent weather resistance and high cost performance.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the invention provides a water-based acrylic polyurethane amino baking pearlescent paint which comprises the following components in parts by mass: 48-57 parts of hydroxyl acrylic acid dispersoid, 10-12 parts of waterborne amino resin, 0.1-0.3 part of pH regulator, 1-6 parts of cosolvent, 10-12 parts of blocked isocyanate curing agent, 5-8 parts of pearl powder, 0.1-0.2 part of defoaming agent, 0.1-0.3 part of dispersing agent, 0.1-0.3 part of wetting agent, 5-22 parts of water, 3-5 parts of pearl powder directional arrangement agent and 0.1-0.6 part of thickening agent; wherein the blocked isocyanate curing agent contains an aliphatic chain segment, an isocyanurate ring and an aromatic ring group.

Further preferably, the waterborne acrylic polyurethane amino baking pearlescent paint comprises the following components in parts by mass: 48-57 parts of hydroxyl acrylic acid dispersoid, 10-12 parts of waterborne amino resin, 0.1-0.3 part of pH regulator, 4.5-5.5 parts of cosolvent, 10-12 parts of blocked isocyanate curing agent, 5-8 parts of pearl powder, 0.1-0.2 part of defoaming agent, 0.1-0.3 part of dispersing agent, 0.1-0.3 part of wetting agent, 7-12 parts of water, 3.5-4.5 parts of pearl powder directional arrangement agent and 0.4-0.6 part of thickening agent.

Preferably, in the waterborne acrylic polyurethane amino baking pearlescent paint, the hydroxy acrylic dispersion is emulsion waterborne hydroxy acrylic resin. The main film forming substance in the formula of the baking pearlescent paint is aqueous hydroxy acrylic resin for amino baking paint, the resin is emulsion type resin, has excellent hardness and flexibility after being crosslinked with amino resin, has high glossiness, good fullness and adhesion, water resistance, oil resistance and alkali resistance, and can be crosslinked with closed isocyanate.

Preferably, in the waterborne acrylic polyurethane amino baking pearlescent paint, the hydroxyl value of the hydroxyl acrylic dispersion is 50 mgKOH/g-100 mgKOH/g.

Preferably, in the waterborne acrylic polyurethane amino baking pearlescent paint, the hydroxyl acrylic dispersion is selected from at least one of Bayhydrol A145, Antkote 2043 and Wantipro 0676.

Preferably, in the aqueous acrylic polyurethane amino baking pearlescent paint, the aqueous amino resin is methyl etherified high imino melamine resin or methyl etherified high imino melamine crosslinking agent.

Preferably, in the waterborne acrylic polyurethane amino baking pearlescent paint, the deblocking temperature of the waterborne amino resin is 120-170 ℃.

In the waterborne acrylic polyurethane amino baking pearlescent paint, the waterborne amino resin can be selected from CYMEL 325, CYMEL303 and CYMEL327 produced by Allnex in the United states, low-methyl-etherified melamine formaldehyde resin BASF072 produced by BASF in Germany, and low-methyl-etherified melamine formaldehyde resin Resimene717 produced by Enlish.

Preferably, in the aqueous acrylic polyurethane amino baking pearlescent paint, the pH regulator is at least one selected from N, N-dimethylethanolamine, triethylamine, isopropanolamine and 2-amino-2-methyl-1-propanol. In order to obtain the best stability in an aqueous system, the pH value is kept between 7 and 9 by using a pH regulator.

Preferably, in the waterborne acrylic polyurethane amino baking pearlescent paint, the cosolvent is alcohol ether; further preferably, the cosolvent is at least one selected from the group consisting of ethylene glycol butyl ether, diethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol butyl ether, dipropylene glycol methyl ether and dipropylene glycol butyl ether; still more preferably, the cosolvent is at least one selected from the group consisting of ethylene glycol monobutyl ether, diethylene glycol butyl ether, and dipropylene glycol methyl ether.

Preferably, in the waterborne acrylic polyurethane amino baking pearlescent paint, the preparation method of the blocked isocyanate curing agent is as follows: the method comprises the steps of taking hexamethylene diisocyanate trimer (HDIT), isophorone diisocyanate (IPDI) and diphenylmethane diisocyanate (MDI) as raw materials, adding polyol to carry out emulsification chain extension reaction, and then adding a sealant to carry out sealing to obtain the sealed isocyanate curing agent.

Preferably, in the waterborne acrylic polyurethane amino baking pearlescent paint, the deblocking temperature of the blocked isocyanate curing agent is 120-170 ℃.

The blocked isocyanate curing agent is prepared by two aliphatic isocyanates, namely hexamethylene diisocyanate trimer and isophorone diisocyanate, and one aromatic isocyanate, namely diphenylmethane diisocyanate, through internal emulsification, chain extension reaction with polyol and addition of a blocking agent. The invention adopts two curing agents to compound, wherein the amino curing agent and the hydroxy acrylic acid are crosslinked at a higher temperature (120-170 ℃), and the formed paint film is compact and has the hardness of more than 2H. Meanwhile, the blocked isocyanate curing agent is also unblocked at 120-170 ℃, and the dissociated isocyanate group (-NCO) is also subjected to a crosslinking reaction with hydroxyl on hydroxyacrylic acid to generate a urethane bond. Therefore, the prepared paint film has better weather resistance and mechanical property.

Preferably, in the preparation method of the blocked isocyanate curing agent, the polyhydric alcohol is polyethylene glycol (PEG-2000) and hexanediol.

More preferably, the preparation method of the blocked isocyanate curing agent specifically comprises the following steps: mixing and stirring hexamethylene diisocyanate trimer, isophorone diisocyanate, diphenylmethane diisocyanate and a solvent, and sequentially adding polyethylene glycol, a chain extender, hexanediol and a sealant for reaction to obtain the blocked isocyanate curing agent.

Preferably, in the preparation method of the blocked isocyanate curing agent, the solvent is 1-methyl-2-pyrrolidone (NMP).

Preferably, in the preparation method of the blocked isocyanate curing agent, the chain extender is 2, 2-dimethylolpropionic acid (DMPA).

Preferably, in the preparation method of the blocked isocyanate curing agent, the blocking agent is Dimethylethanolamine (DMEA) and 3, 5-Dimethylpyrazole (DMP).

More preferably, in the specific preparation method of the blocked isocyanate curing agent, the temperature for mixing and stirring the hexamethylene diisocyanate trimer, the isophorone diisocyanate, the diphenylmethane diisocyanate and the solvent is 40-60 ℃.

Further preferably, in the specific preparation method of the blocked isocyanate curing agent, the temperature for adding the polyethylene glycol, the chain extender, the hexanediol and the blocking agent to react is 60-80 ℃.

Preferably, the blocked isocyanate curing agent is prepared from the following components in parts by mass: 90-100 parts of hexamethylene diisocyanate trimer, 2-2.5 parts of isophorone diisocyanate, 2-2.5 parts of diphenylmethane diisocyanate, 25-30 parts of 1-methyl-2-pyrrolidone, 8-10 parts of polyethylene glycol, 4-5 parts of 2, 2-dimethylolpropionic acid, 0.5-1 part of hexanediol, 2.5-3.5 parts of dimethylethanolamine and 30-40 parts of 3, 5-dimethylpyrazole.

In some preferred embodiments of the present invention, the blocked isocyanate curing agent is prepared by: mixing and stirring 90-100 parts by mass of hexamethylene diisocyanate trimer, 2-2.5 parts by mass of isophorone diisocyanate, 2-2.5 parts by mass of diphenylmethane diisocyanate and 25-30 parts by mass of 1-methyl-2-pyrrolidone at 40-60 ℃ for 20-60 min; gradually adding 8-10 parts by mass of polyethylene glycol, and keeping the temperature at 65-75 ℃ for 40-80 min; maintaining the temperature at 65-75 ℃, adding 4-5 parts by mass of 2, 2-dimethylolpropionic acid, stirring for 20-60 min, adding 0.5-1 part by mass of hexanediol, keeping the temperature for 1-2 h, adding 2.5-3.5 parts by mass of dimethylethanolamine, stirring for 5-30 min, adding 30-40 parts by mass of 3, 5-dimethylpyrazole, and stirring for 2-10 min to obtain the closed isocyanate curing agent.

Preferably, in the waterborne acrylic polyurethane amino baking pearlescent paint, the particle size of the pearlescent powder is 400-600 meshes.

Preferably, in the waterborne acrylic polyurethane amino baking pearlescent paint, the pearlescent powder contains mica and titanium dioxide; more preferably, the pearl powder is composed of 69-73% of mica and the balance of rutile titanium dioxide.

Preferably, in the waterborne acrylic polyurethane amino baking pearlescent paint, the defoaming agent is polysiloxane polyether copolymer. The used defoaming agent has obvious incompatibility with the coating, eliminates large bubbles and micro foams, and reduces fish eyes and shrinkage cavities. Further preferably, the defoaming agent is selected from Tego-840, Digao, Surfynol MD20, BYK-011, BYK-020, BYK-019, BYK-011, BYK-019, BYK-O-K.

Preferably, in the aqueous acrylic polyurethane amino baking pearlescent paint, the dispersant is at least one selected from a polycarboxylate sodium salt dispersant and a copolymer containing pigment affinity groups; further preferably, the dispersant is at least one selected from Dow OROTAN731A, BYK-192, Additol VXW 6208/60.

Preferably, in the waterborne acrylic polyurethane amino baking pearlescent paint, the wetting agent is selected from at least one of organosilicon gemini structure surfactants, nonionic organic surfactants and polyether siloxane copolymers. The use of these types of wetting agents can enhance the wetting of the pearlescent paint with the substrate. Further preferably, the wetting agent is at least one selected from the group consisting of Tego-4100, Tego-510, and Tego-245.

Preferably, in the aqueous acrylic polyurethane amino baking pearlescent paint, the pearlescent powder alignment agent is selected from at least one of aqueous polyamide wax slurry, aqueous acrylic rheological auxiliary agent and ethylene-vinyl acetate copolymer wax emulsion. The ethylene vinyl acetate copolymer wax emulsion is preferably a nonionic modified ethylene vinyl acetate copolymer wax (EVA) emulsion. The use of the pearl powder directional arrangement agent can reduce the Benard vortex of the pearl powder and achieve good arrangement effect. Further preferably, the pearlescent powder alignment agent is selected from BYK-8421, WT-128 and WT-305 of Changxing Kyoho polymer materials.

Preferably, in the aqueous acrylic polyurethane amino baking pearlescent paint, the thickener is at least one selected from anionic polymer water swelling type water phase thickener and nonionic polyurethane associated thickener; further preferably, the thickener is at least one selected from the group consisting of Lamberti PS 166, Lamberti PS167, and Dow ASE-60.

The invention also provides a preparation method of the waterborne acrylic polyurethane amino baking pearlescent paint.

The preparation method of the water-based acrylic polyurethane amino baking pearlescent paint comprises the following steps:

1) mixing and stirring pearl powder, a cosolvent, a dispersant, a wetting agent and water to obtain pearl slurry, and curing for later use;

2) mixing and stirring the hydroxyl acrylic acid dispersoid, the waterborne amino resin, the pH regulator, the blocked isocyanate curing agent, the defoaming agent and the pearl powder directional arrangement agent, then adding the pearl slurry, mixing and stirring, and then adding the thickening agent to regulate the viscosity, thus obtaining the waterborne acrylic polyurethane amino baking pearl paint.

Preferably, in the step 1) of the preparation method of the waterborne acrylic polyurethane amino baking pearlescent paint, the rotation speed of mixing and stirring is 400rpm (r/min) to 600rpm, and the time of mixing and stirring is 0.5h to 2 h.

Preferably, in the step 1) of the preparation method of the water-based acrylic polyurethane amino baking pearlescent paint, the curing is standing curing, and the curing time is 12-24 hours.

Preferably, the preparation method of the water-based acrylic polyurethane amino baking pearlescent paint comprises the step 2) of mixing and stirring the hydroxyl acrylic dispersion, the water-based amino resin, the pH regulator, the blocked isocyanate curing agent, the defoaming agent and the pearlescent powder directional arrangement agent at the rotating speed of 600-1000 rpm for 20-40 min, then regulating the rotating speed to 400-600 rpm, dropwise adding the pearlescent slurry, continuously stirring for 20-40 min, adding the thickening agent to regulate the viscosity, and uniformly stirring to obtain the water-based acrylic polyurethane amino baking pearlescent paint.

Preferably, in the step 2) of the preparation method of the waterborne acrylic polyurethane amino baking pearlescent paint, the stormer viscosity is adjusted to be 80 KU-90 KU at 25 ℃.

The preparation method of the water-based acrylic polyurethane amino baking pearlescent paint is realized by using a common high-speed dispersion machine for paint preparation.

The water-based acrylic polyurethane amino baking pearlescent paint can be applied by a spraying method, and the thickness of a paint film is controlled to be 5-50 mu m.

The invention has the beneficial effects that:

the waterborne pearlescent paint disclosed by the invention is low in VOC content, excellent in environmental protection performance, high in crosslinking density of a paint film, full in paint film, high in glossiness, high in hardness, good in mechanical property and excellent in adhesive force. The water-based pearlescent paint has good directional arrangement effect of the pearlescent powder and excellent pearlescent effect, and is suitable for mechanical equipment. Meanwhile, the paint is a single component, so that the paint is convenient to construct, stable in performance and wide in application prospect.

Compared with the prior art, the invention has the following advantages:

1. the resin adopted by the invention is all water-based resin, and the used auxiliary agent is also an environment-friendly solvent, so that the VOC content is low, and the method is safe and environment-friendly.

2. The self-made water-based blocked polyurethane curing agent comprises an isocyanurate ring of hexamethylene diisocyanate tripolymer, an aliphatic chain segment and an aromatic ring provided by diphenylmethane diisocyanate, and the composite structure of the three groups provides good yellowing resistance and mechanical property for a paint film, so that the self-made water-based blocked polyurethane curing agent is suitable for outdoor use.

3. The invention adopts the pre-dispersion curing process, solves the problem that the pearlescent pigment is not easy to disperse; the specific pearl powder orienting agent is adopted to obtain the pearl powder arrangement effect equivalent to the solvent type coating effect, and the directional arrangement of the pearl powder is good. The problem that the pearly-lustre powder with specific meshes is easy to be granulated in a paint film is solved by matching the pearly-lustre powder with a pre-dispersing curing process, and the arrangement effect of the pearly-lustre powder equivalent to that of a solvent type paint is obtained.

4. The baking temperature of the pearlescent paint is adjustable, the pearlescent paint can form a film at 120-170 ℃, and the pearlescent paint can be baked for 15-20 minutes.

Detailed Description

The present invention will be described in further detail with reference to specific examples. The starting materials, reagents or apparatus used in the examples and comparative examples were obtained from conventional commercial sources unless otherwise specified. Unless otherwise indicated, the testing or testing methods are conventional in the art. The "parts" used in the following examples/comparative examples are "parts by mass" unless otherwise specified.

The pearl powder used in the examples/comparative examples was composed of 70 wt% of mica and 30 wt% of rutile type titanium dioxide.

The compositions of the raw materials used in the pearlescent paints of examples 1 to 7 are shown in Table 1.

TABLE 1 compositions of pearlescent paints of examples 1-7

Example 1

The composition of the aqueous acrylic polyurethane amino baking pearlescent paint of the present example is shown in table 1, and the preparation method is as follows:

1) 100 parts of hexamethylene diisocyanate trimer, 2.5 parts of isophorone diisocyanate, 2.5 parts of diphenylmethane diisocyanate and 30 parts of 1-methyl-2-pyrrolidone are uniformly mixed at 50 ℃ and stirred for 30 minutes. 10 parts of polyethylene glycol are gradually added and the mixture is kept at 70 ℃ for 1 hour. 5 parts of 2, 2-dimethylolpropionic acid was added thereto, and the mixture was stirred at 70 ℃ for 30 minutes. 1 part of hexanediol was added and the mixture was incubated at 70 ℃ for 1.5 hours. 3.5 parts dimethylethanolamine was added thereto and stirred for 10 minutes. 40 parts of 3, 5-dimethylpyrazole are added, and the mixture is stirred for 5 minutes at 70 ℃ to obtain a blocked isocyanate curing agent, named A-1, for later use.

2) Under the stirring condition of the rotating speed of 600rpm, according to the mass ratio, 8 parts of 400-mesh pearl powder, 5 parts of ethylene glycol monobutyl ether, 9.8 parts of tap water, BYK-1920.1 parts of dispersant and Tego-41000.1 parts of wetting agent are sequentially added, stirred for 60 minutes, and the pearl powder slurry with uniform dispersion is prepared, is statically aged for 24 hours and is named B-1 for later use.

3) Under the stirring condition of the rotating speed of 1000rpm, according to the mass ratio of table 1, Antkote 204348 parts, CYMEL 32512 parts, 2-amino-2-methyl-1-propanol 0.3 parts, blocked isocyanate curing agent A-112 parts, BYK-0110.1 parts and BYK-84214 parts are added in sequence. After stirring for 30 minutes, adjusting the rotation speed to 600rpm, slowly dropwise adding the pearl powder slurry B-1 prepared in the step 2), continuing stirring for 30 minutes, adding 0.5 part of thickener LAMBERTI PS 166 to adjust the viscosity to 85KU (measured by a stormer viscometer at 25 ℃), and uniformly stirring to obtain the waterborne acrylic polyurethane amino baking pearl paint.

Example 2

1) 90 parts of hexamethylene diisocyanate trimer, 2.5 parts of isophorone diisocyanate, 2.5 parts of diphenylmethane diisocyanate and 30 parts of 1-methyl-2-pyrrolidone are uniformly mixed at 50 ℃ and stirred for 30 minutes. Gradually adding 8 parts of polyethylene glycol, and keeping the temperature at 70 ℃ for 1 hour. 4.5 parts of 2, 2-dimethylolpropionic acid was added thereto, and the mixture was stirred for 30 minutes while maintaining the temperature at 70 ℃. 0.5 part of hexanediol was added and the mixture was incubated at 70 ℃ for 1.5 hours. 3 parts of dimethylethanolamine was added and stirred for 10 minutes. 35 parts of 3, 5-dimethylpyrazole are added, and the mixture is stirred for 5 minutes at 70 ℃ to obtain a blocked isocyanate curing agent, named A-2, for later use.

2) Under the stirring condition of the rotating speed of 600rpm, 6 parts of 600-mesh pearl powder, 5 parts of dipropylene glycol methyl ether, 12 parts of tap water, 0.1 part of dispersant 731A and 78 parts of wetting agent Tego-5100.1 are sequentially added according to the mass ratio, stirred for 60 minutes to prepare uniformly-dispersed pearl powder slurry, and the uniformly-dispersed pearl powder slurry is kept stand and cured for 24 hours to be named B-2 for later use.

3) Under the stirring condition of the rotating speed of 1000rpm, Bayhydrol A14557 parts, CYMEL 32712 parts, N-dimethylethanolamine 0.3 part, blocked isocyanate curing agent A-210 parts in the step (1), Surfynol MD 200.1 parts and WT-3054 parts are sequentially added according to the mass ratio of Table 1. After stirring for 30 minutes, adjusting the rotation speed to 600rpm, slowly dropwise adding the pearl powder slurry B-2 prepared in the step 2), continuing stirring for 30 minutes, adding 0.5 part of thickener LAMBERTI PS167 to adjust the viscosity to 85KU (measured by a stormer viscometer at 25 ℃), and uniformly stirring to obtain the waterborne acrylic polyurethane amino baking pearl paint.

Example 3

1) 100 parts of hexamethylene diisocyanate trimer, 2 parts of isophorone diisocyanate, 2 parts of diphenylmethane diisocyanate and 25 parts of 1-methyl-2-pyrrolidone are uniformly mixed at 50 ℃ and stirred for 30 minutes. 9 parts of polyethylene glycol are gradually added and the mixture is kept at 70 ℃ for 1 hour. 5 parts of 2, 2-dimethylolpropionic acid was added thereto, and the mixture was stirred at 70 ℃ for 30 minutes. 1 part of hexanediol was added and the mixture was incubated at 70 ℃ for 1.5 hours. 3 parts of dimethylethanolamine was added and stirred for 10 minutes. 40 parts of 3, 5-dimethylpyrazole are added, and the mixture is stirred for 5 minutes at 70 ℃ to obtain a blocked isocyanate curing agent, named A-3, for later use.

2) Under the stirring condition of the rotating speed of 600rpm, 5 parts of 400-mesh pearl powder, 5 parts of diethylene glycol monobutyl ether, 7.4 parts of tap water, 6208/600.3 parts of dispersant and Tego-2450.3 parts of wetting agent are sequentially added according to the mass ratio, stirred for 60 minutes to prepare uniformly dispersed pearl powder slurry, and the uniformly dispersed pearl powder slurry is kept stand and cured for 24 hours to be named B-3 for later use.

3) Under the stirring condition of the rotating speed of 1000rpm, BayhydrolA 14557 parts, BASF 07210 parts, triethylamine 0.1 part, blocked isocyanate curing agent A-310 parts, BYK-0200.1 parts and WT-3054 parts are added in sequence according to the mass ratio. After stirring for 30 minutes, adjusting the rotation speed to 600rpm, slowly dropwise adding the pearl powder slurry B-3 prepared in the step 2), continuing stirring for 30 minutes, adding 0.5 part of a thickening agent Dow ASE-60, adjusting the viscosity to 85KU (measured by a stormer viscometer at 25 ℃), and uniformly stirring to obtain the waterborne acrylic polyurethane amino baking pearl paint.

Example 4

The composition of the aqueous acrylic polyurethane amino baking pearlescent paint of this example is shown in Table 1, the raw materials were added in the composition shown in Table 1, and the rest of the preparation method was the same as that of example 1.

Example 5

The composition of the aqueous acrylic polyurethane amino baking pearlescent paint of this example is shown in Table 1, the raw materials were added according to the composition of Table 1, and the rest of the preparation method was the same as that of example 2.

Example 6

The composition of the aqueous acrylic polyurethane amino baking pearlescent paint of this example is shown in Table 1, the raw materials were added in the composition shown in Table 1, and the rest of the preparation method was the same as that of example 3.

Example 7

The compositions of the raw materials used in the pearlescent paints of comparative examples 1 to 7 are shown in Table 2.

TABLE 2 pearlescent paint compositions of comparative examples 1-7

The blocked isocyanate curing agents A-1, A-2 and A-3 in Table 2 were prepared in the same manner as in Table 1.

The preparation method of comparative examples 1 to 7 is as follows:

under the stirring condition of the rotating speed of 600rpm, according to the mass ratio of table 2, the hydroxyl acrylic acid dispersoid, the waterborne amino resin, the pH regulator, the blocked isocyanate curing agent, the cosolvent, the defoamer, the wetting agent, the dispersant, the pearl powder, the tap water and the pearl powder directional arrangement agent are sequentially added. And (3) after stirring for 30 minutes, adding a thickening agent to adjust the viscosity to 85KU (measured by a stormer viscometer at 25 ℃), and uniformly stirring to obtain the waterborne acrylic polyurethane amino baking pearlescent paints of comparative examples 1-7.

The results of the tests of the pearlescent paints of examples 1 to 7 are shown in Table 3. The results of the tests of the pearlescent paints of comparative examples 1 to 7 are shown in Table 4.

The index detection methods or criteria in tables 3 and 4 are as follows, respectively:

pencil hardness; GB/T6739;

adhesion force: GB/T9286, test 1mm for drawing a grid;

impact resistance: GB/T1732;

flexibility: GB/T1731;

water resistance: GB/T5209;

aging a xenon lamp: GB/T1766;

VOC：GB 24409；

pearl powder arrangement, pearl effect, color and luster, and atomization effect: visual inspection was carried out.

TABLE 3 test results for pearlescent paints of the examples

Index (I)

Example 1

Example 2

Example 3

Example 4

Example 5

Example 6

Example 7

Hardness of pencil

2H

3H

Adhesion force

Level 1

Impact resistance (cm)

50

Flexibility

1mm

Water resistance (hours)

72

Xenon lamp aging (hours)

600

700

600

700

VOC(g/L)

80

85

80

65

70

75

81

Arrangement of pearl powder

Is tidy and uniform

Pearlescent effect

Pearly luster is soft

Color and luster

Light brightness

Atomization effect

Has good atomization effect

TABLE 4 test results for pearlescent paints of comparative examples

From the test results in tables 3 and 4, it can be seen that the pearlescent paints in examples 1 to 7 adopt the pearlescent powder pre-dispersion process, the directional arrangement of the pearlescent powder is good, the pearlescent luster is soft, and the luster is bright. Compared with the prior art that the raw materials are added in sequence, the pearl powder has poor dispersion effect, patterns are easy to appear on a paint film, the phenomenon of pattern formation is caused, the construction atomization effect is poor, and a spray gun is easy to block.

The self-made closed isocyanate curing agent is adopted in the embodiments 1-7 and the comparative examples 1-3, the adhesive force of a paint film is 1 grade, the impact resistance can reach 50cm, the flexibility is 1mm, the water resistance is 72 hours, the xenon lamp aging can reach more than 600 hours, and the self-made closed isocyanate curing agent has excellent yellowing resistance. In comparative examples 4-6, a self-made closed isocyanate curing agent is not added, the adhesive force is only 2 grade, the flexibility is 2mm, the water resistance is 48 hours, and the xenon lamp aging is only 400 hours. Compared with the self-made curing agents in examples 1 to 7, the Bayhydur XP2706 closed curing agent added in the comparative example 7 has the defects of insufficient mechanical property and slightly poor weather resistance of a paint film.

The water-based acrylic polyurethane amino baking pearlescent paint can be applied by a spraying method, and the thickness of a paint film is controlled to be 5-50 mu m. The baking temperature of the pearlescent paint is adjustable, the pearlescent paint can be formed into a film at 120-170 ℃, and the pearlescent paint can be baked for 15-20 minutes.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. The water-based acrylic polyurethane amino baking pearlescent paint is characterized in that: the paint comprises the following components in parts by mass: 48-57 parts of hydroxyl acrylic acid dispersoid, 10-12 parts of waterborne amino resin, 0.1-0.3 part of pH regulator, 1-6 parts of cosolvent, 10-12 parts of blocked isocyanate curing agent, 5-8 parts of pearl powder, 0.1-0.2 part of defoaming agent, 0.1-0.3 part of dispersing agent, 0.1-0.3 part of wetting agent, 5-22 parts of water, 3-5 parts of pearl powder directional arrangement agent and 0.1-0.6 part of thickening agent;

the blocked isocyanate curing agent contains an aliphatic chain segment, an isocyanurate ring and an aromatic ring group.

2. The aqueous acrylic polyurethane amino baking pearlescent paint of claim 1, characterized in that: the hydroxyl acrylic dispersion is emulsion type water-based hydroxyl acrylic resin.

3. The aqueous acrylic polyurethane amino baking pearlescent paint of claim 1, characterized in that: the water-based amino resin is methyl etherified high imino group melamine resin.

4. The aqueous acrylic polyurethane amino baking pearlescent paint of claim 1, characterized in that: the cosolvent is alcohol ether.

5. The aqueous acrylic polyurethane amino baking pearlescent paint of claim 1, characterized in that: the preparation method of the blocked isocyanate curing agent comprises the following steps: adding polyol into hexamethylene diisocyanate tripolymer, isophorone diisocyanate and diphenylmethane diisocyanate as raw materials to perform an emulsifying chain extension reaction, and then adding a sealing agent to seal to obtain the sealed isocyanate curing agent.

6. The aqueous acrylic polyurethane amino baking pearlescent paint of claim 1, characterized in that: the particle size of the pearl powder is 400-600 meshes.

7. The aqueous acrylic polyurethane amino baking pearlescent paint of claim 1, characterized in that: the defoaming agent is polysiloxane polyether copolymer.

8. The aqueous acrylic polyurethane amino baking pearlescent paint of claim 1, characterized in that: the dispersant is at least one selected from a sodium polycarboxylate dispersant and a copolymer containing pigment affinity groups.

9. The aqueous acrylic polyurethane amino baking pearlescent paint of claim 1, characterized in that: the pearl powder directional arrangement agent is selected from at least one of water-based polyamide wax slurry, water-based acrylic rheological additive and ethylene-vinyl acetate copolymer wax emulsion.

10. A preparation method of the water-based acrylic polyurethane amino baking pearlescent paint as set forth in any one of claims 1-9 is characterized in that: the method comprises the following steps: