CN109401506B

CN109401506B - Waterborne interference pearlescent flashing paint for automobiles and preparation method thereof

Info

Publication number: CN109401506B
Application number: CN201811169139.3A
Authority: CN
Inventors: 王玉廷
Original assignee: Beijing Chenxin Hengda Technology Co ltd
Current assignee: Beijing Chenxin Hengda Technology Co.,Ltd.
Priority date: 2018-10-08
Filing date: 2018-10-08
Publication date: 2021-06-25
Anticipated expiration: 2038-10-08
Also published as: CN109401506A

Abstract

The invention discloses an aqueous interference pearlescent flashing paint for an automobile and a preparation method thereof. The water-based interference pearlescent flashing paint comprises the following components: mica pearl powder dispersion slurry, aqueous polyurethane dispersion, self-thickening acrylic emulsion, aqueous amino resin, a thickening agent, an amine neutralizer, a diluting agent and water. The water-based interference pearlescent flashing paint has scientific proportioning, mutually coordinated components, high drying speed and good construction performance, meets the requirements of a 2C1B coating process on paint, greatly saves the cost, reduces the energy consumption and has the advantages of energy conservation and emission reduction. The paint film formed by the pearlescent flashing paint is gorgeous and soft in gloss, has pearlescent color, is rich in aesthetic feeling, does not have the phenomena of chromatic aberration, blooming, graining, light loss or poor pearlescent effect and the like, has excellent water resistance and corrosion resistance and good weather resistance, and meets the decorative requirement of high-grade cars.

Description

Waterborne interference pearlescent flashing paint for automobiles and preparation method thereof

Technical Field

The invention belongs to the technical field of coatings, and particularly relates to an aqueous interference pearlescent flashing paint for an automobile and a preparation method thereof.

Background

In addition to the active shift to green and environmental protection, the development of modern automotive coatings also strives to impart good aesthetics to automobiles. The color of the automobile body gradually becomes a mark showing the individuality of the automobile owner, people have higher and higher requirements on high decoration of the automobile finish, and besides the traditional pure-color paint, the metal flashing paint, the pearlescent paint and other high-grade colored paints are more and more favored by people. According to statistics, more than 70% of the current domestic and foreign car colored paints are metallic or pearlescent or mixed colors of more than two pigments, and the requirements of the two are increasing.

The pearlescent paint has gorgeous and soft luster and colorful color, and is a common colored paint for high-grade bridge cars. There are two kinds of pearlescent paint, one is 2C1B system comprising pearlescent prime paint and finishing paint, and the other is 3C2B system comprising colored base coat, middle coat containing pearlescent pigment and finishing paint. The pearlescent pigment is prepared by plating a layer of titanium dioxide, ferric oxide or chromium oxide on the surface of superfine mica powder, and the pearlescent pigment is different from aluminum powder, not only has surface reflectivity but also has light transmittance, so that the pearlescent pigment has brightness different from metal color. Light rays can show various interference colors when passing through a paint film formed by plating a thin titanium dioxide coating on the surface of the mica powder, wherein the interference colors of yellow, red, purple, blue and green are generated according to the difference of the thickness of the titanium dioxide coating. The pearlescent pigment is suitable for almost all natural and synthetic resins, and the prepared colored paint has long-term ultraviolet radiation resistance, good heat resistance, weather resistance and acid rain resistance, and is particularly suitable for surface decoration of cars. Practice proves that the pearlescent pigment can keep luster in alkaline water paint, and electrostatic spraying does not generate electric spark, which are beyond the metallic pigment. However, since the pearlescent pigment contacts various complex electrolyte solutions during the manufacturing process, the surface properties are very complex, especially the surface of the pigment is free-OH, so that the pigment cannot be wetted by the non-polar resin solution, the pigment is not uniformly dispersed in the paint, and a series of defects such as flocculation, precipitation, flooding, thixotropy and the like are generated. Limiting its use.

In addition, compared with common colored paint, the pearlescent paint has higher requirements on paint formula and construction, otherwise, the phenomena of color difference, blooming, grain rising, light loss or poor pearlescent effect and the like are easily generated. Such as: insufficient flash-off time or solvent mismatch between the overprint varnish and the pearlescent paint, i.e., the pearlescent paint does not reach a sufficient separation time, "insufficient drying" causes part of the pearlescent pigment to be dissolved by the varnish, with the result that the pearlescent pigment or other pigment particles in the pearlescent paint float up and change their position, causing color differences and blooming (cloudiness); the viscosity of the coating is not properly adjusted, and the larger the using amount of the diluent is, the lower the viscosity of the base paint is, the more easily the defects of paint films such as flooding, floating and the like are generated, and the color difference is generated; the pearlescent pigment has complex surface property, is unevenly dispersed in paint, and has the phenomena of flocculation, precipitation, granulation and poor pearlescent effect; the weather resistance and corrosion resistance of the resin base material are not enough or the selected pearlescent pigment is not appropriate, so that the paint film is easy to lose gloss.

The prior art mainly overcomes the defects by improving the formula composition of the pearlescent paint. For example, chinese patent application publication No. CN 108192438A discloses an aqueous adjuvant capable of improving workability of aqueous metal and pearlescent paint, and a preparation method thereof, wherein the aqueous adjuvant comprises the following raw materials by weight: 10-35% of aqueous polyurethane emulsion, 1-2.5% of alkali swelling thickener, 0.2-1% of association thickener, 0.05-0.5% of modified organic bentonite, 0.1-0.4% of amine neutralizer, 1-5% of n-amyl alcohol and 60-80% of deionized water.

Although the improvement of the prior art on the pearlescent paint has obtained a lot of progress, still need to provide a new waterborne interference pearlescent glitter paint formula, on the basis of the characteristics of the original paint, the advantages are raised and the disadvantages are avoided, and various performance indexes are further improved, and specifically, the waterborne interference pearlescent glitter paint for the automobile, which not only meets the 2C1B system, has good construction performance, but also has high adhesive force, water resistance, corrosion resistance and good weather resistance, so that the obtained paint film has pearlescent color, does not have the phenomena of chromatic aberration, blooming, grain rising, light loss or poor pearlescent effect, and the like, and better meets the market demand.

Disclosure of Invention

The invention aims to provide the water-based interference type pearlescent flashing paint for the automobile and the preparation method thereof, the water-based interference type pearlescent flashing paint has the advantages of good construction performance, strong water resistance and weather resistance, and the obtained paint film has gorgeous and soft luster and is rich in aesthetic feeling, and meets the decorative requirement of high-grade cars.

The invention is realized by the following technical scheme:

the waterborne interference pearlescent flashing paint for the automobile comprises the following components in percentage by mass: 15-25% of mica pearl powder dispersion slurry, 5-10% of an aqueous polyurethane dispersion, 25-35% of a self-thickening acrylic emulsion, 2-4% of an aqueous amino resin, 1-3% of a thickening agent, 2-4% of an amine neutralizing agent, 2-5% of a diluting agent and 25-30% of water.

Preferably, the waterborne interference pearlescent flashing paint for the automobile comprises the following components in percentage by mass: 20% of mica pearl powder dispersion slurry, 8% of aqueous polyurethane dispersion, 30% of self-thickening acrylic emulsion, 3% of aqueous amino resin, 2% of thickening agent, 3% of amine neutralizing agent, 4% of diluting agent and 30% of water.

Preferably, the thickener is composed of an alkali swelling thickener and organic bentonite according to a mass ratio of 1 (0.1-0.2).

Preferably, the alkali swelling thickener is Rohm and Hass ASE 60.

Preferably, the amine neutralizer is Haimax MA-95.

Preferably, the diluent is composed of propylene glycol methyl ether acetate and n-bromopropane in a mass ratio of 1 (0.5-1).

The mica pearl powder dispersion slurry comprises the following components in percentage by mass: 40-50% of mica titanium pearl powder, 2-5% of wetting dispersant, 2-6% of rheological modified wax emulsion, 4-8% of active humectant and 40-45% of ethylene glycol butyl ether.

Preferably, the wetting and dispersing agent is digao TEGO-655 or Effka EFKA-5056.

Preferably, the rheology-modified wax emulsion is Pico AQUATIX 8421.

Preferably, the active humectant is pentaerythritol palmitate.

Preferably, the mica titanium pearl powder is interference red pearl powder, interference yellow pearl powder or interference blue pearl powder. The trade name of the interference red pearl powder is Merck T60-21, the trade name of the interference yellow pearl powder is Merck T60-20, and the trade name of the interference blue pearl powder is Merck T60-23.

The mica pearl powder dispersion slurry is obtained by simple stirring, and specifically, the preparation of the mica pearl powder dispersion slurry comprises the following steps: mixing ethylene glycol monobutyl ether, an active humectant, a rheology modified wax emulsion and a wetting dispersant according to the formula amount, stirring for 8-10 minutes, then adding mica titanium pearl powder according to the formula amount, and stirring for 4-5 minutes to obtain mica pearl powder dispersion slurry.

The waterborne interference pearlescent flashing paint disclosed by the invention takes a waterborne polyurethane dispersion, a self-thickening acrylic emulsion and a waterborne amino resin as film-forming materials, wherein the waterborne polyurethane dispersion is preferably Kadsura Bayhydrol UH2952/1 or Kadsura Bayhydrol UH 2621; the waterborne amino resin is Zhan Xin Cymel325, Zhan Xin Cymel 327, basf Luwipal 052 or basf Luwipal 073; the self-thickening acrylic emulsion is a self-made product.

The preparation method of the self-thickening acrylic emulsion refers to the development of self-thickening core-shell acrylic emulsion published by Zhuang Zhenyu, Dai and the like, the coating industry, 2015,45(3), and Chinese patent application with publication number CN 105199049A, and discloses a hydroxyl acrylic emulsion with a core-shell structure and a preparation method thereof, and specifically, the preparation method of the self-thickening acrylic emulsion comprises the following steps:

(1) dissolving 1-5% of sodium dodecyl benzene sulfonate in 10-30% of deionized water, dropwise adding 30-55% of methyl methacrylate and 15-25% of butyl acrylate under stirring at the rotating speed of 800-2000 rpm, finishing dropping within 0.5h, and stirring for 1h after finishing dropping to prepare a core layer pre-emulsion;

(2) dissolving 1-5% of sodium dodecyl benzene sulfonate in 10-30% of deionized water, dropwise adding 6-12% of methacrylic acid, 20-40% of hydroxyethyl methacrylate and 15-30% of butyl acrylate under stirring at the rotating speed of 800-2000 rpm, finishing dropping within 0.5h, and stirring for 1h after finishing dropping to prepare a shell layer pre-emulsion;

(3) adding 30-65% of deionized water and 0.1-0.5% of sodium dodecyl benzene sulfonate into a four-neck flask provided with a stirrer, a condenser pipe and a two-neck connecting pipe under the protection of nitrogen, uniformly stirring, heating to 80-85 ℃ in a constant-temperature water bath kettle, dropwise adding 30-65% of the nuclear layer pre-emulsion prepared in the step (1) and 0.5-5% of ammonium persulfate aqueous solution (5 wt%), and finishing dropwise adding within 2-3 h to prepare a nuclear layer emulsion;

(4) taking 15-70% of the core-layer emulsion prepared in the step (3), keeping the temperature at 80-85 ℃, dropwise adding 10-80% of the shell-layer pre-emulsion prepared in the step (2) and 0.5-5% of ammonium persulfate aqueous solution (5 wt%), finishing dropwise adding within 2-3 h, controlling the temperature between 80-85 ℃, keeping the temperature for 1h, finishing the reaction, adding 0.5-4% of N, N-dimethylethanolamine and 1.5-12% of deionized water to adjust the pH value to 4-7, filtering, and discharging to obtain the self-thickening acrylic emulsion.

The sum of the raw materials of the steps of (1) the core layer pre-emulsion, (2) the shell layer pre-emulsion, (3) the core layer emulsion and (4) the self-thickening acrylic emulsion is 100%, and the percentage of the percentage homogenization quantity is percentage.

In addition, the invention also provides a preparation method of the waterborne interference type pearlescent flash paint for the automobile, which comprises the following steps:

(1) sequentially adding the aqueous polyurethane dispersion, the self-thickening acrylic emulsion, the aqueous amino resin, the thickening agent and the amine neutralizing agent into water at a stirring speed of 400-500 rpm, and stirring for 20-30 min;

(2) and (2) adding the mica pearl powder dispersion slurry and a diluent into the material obtained in the step (1), stirring for 5-7 minutes at 40-50 rpm to obtain the mica pearl powder dispersion slurry.

According to the invention, mica titanium pearl powder is prepared into mica pearl powder dispersion slurry in advance, and then the dispersion slurry is added into the coating to prepare the pearl flashing paint, so that the dispersion uniformity and stability of the pearl pigment in the paint can be obviously improved, the pearl pigment is promoted to be arranged parallel to the bottom surface to form better parallel orientation, and specifically, the wetting dispersant is added, so that the dispersibility of the mica titanium pearl powder can be improved, and the pearl powder is prevented from coagulating and precipitating; the addition of the rheology modified wax emulsion can improve the orientation of the pearlescent pigment and reduce cloud-block-shaped color difference/mottle; adding active humectant pentaerythritol palmitate to form a film on the surface of the pearlescent pigment to prevent the solvent in the finishing varnish from redissolving the pearlescent pigment.

The self-thickening acrylic emulsion and the aqueous polyurethane dispersion prepared by a specific formula are used as main film forming materials, both of the self-thickening acrylic emulsion and the aqueous polyurethane dispersion have quick drying performance, so that the phenomenon of bottom biting between paint films can be avoided when a wet-on-wet spraying process is used for coating, and the aqueous amino resin is added for crosslinking and curing, so that the paint film has excellent water resistance. Meanwhile, the acrylic emulsion has good self-thickening property and thixotropy, so that the rheological property of the coating can be improved, the coating does not generate sagging during construction, and the directional arrangement of the pearl powder is promoted. Since the self-thickening acrylic emulsion is used as a film forming material and a thixotropic agent in the pearlescent paint, the influence of the thickening agent on the water resistance of a paint film can be relieved to a certain extent, and the water resistance of the paint film is improved. Furthermore, a diluent consisting of propylene glycol methyl ether acetate and n-bromopropane is added into the formula of the pearlescent paint to promote solvent volatilization, so that the primer paint can be dry to touch before being coated with the finishing paint, and the pearlescent paint is continuously sprayed twice in a high-humidity environment of more than 90 percent.

However, the inventor finds that the polar solvents of ethylene glycol butyl ether, the diluents of propylene glycol methyl ether acetate and n-bromopropane can reduce the self-thickening property and thixotropy of the self-thickening acrylic emulsion, and the coating which only uses the self-thickening acrylic emulsion as the thixotropy agent can not meet the construction requirement. The addition of the thickener formed by compounding the alkali swelling thickener and the organic bentonite can overcome the defects, so that the paint still keeps better thixotropic property and flash index after long-time storage. Meanwhile, the self-thickening acrylic emulsion is compounded with the alkali swelling thickener and the organic bentonite, so that the influence of the alkali swelling thickener and the organic bentonite on the water resistance of the paint can be reduced, the water resistance of a paint film is improved, the surface tension of the aqueous polyurethane dispersion can be reduced, the pearl powder is not suspended and accumulated, the paint surface can be directly arranged once being sprayed, and the surface is smooth and does not prick hands.

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

(1) the water-based interference type pearlescent flashing paint for the automobile, provided by the invention, has the advantages of scientific proportioning, mutual coordination of all components, high drying speed and good construction performance, meets the requirements of a 2C1B coating process on the paint, greatly saves the cost, reduces the energy consumption, and has the advantages of energy conservation and emission reduction.

(2) The paint film formed by the pearlescent flashing paint disclosed by the invention is gorgeous and soft in gloss, has pearlescent color, is rich in aesthetic feeling, does not have the phenomena of chromatic aberration, blooming, graining, dullness or poor pearlescent effect and the like, is excellent in water resistance and corrosion resistance and good in weather resistance, and meets the decorative requirement of high-grade cars.

Detailed Description

The following examples are further illustrative of the present invention and are not intended to be limiting thereof.

Example 1 preparation of self-thickening acrylic emulsions

(1) Dissolving 2g of sodium dodecyl benzene sulfonate in 20g of deionized water, dropwise adding 55g of methyl methacrylate and 23g of butyl acrylate under stirring at the rotating speed of 1000rpm, finishing dropping within 0.5h, and stirring for 1h after finishing dropping to prepare a nuclear layer pre-emulsion;

(2) dissolving 2g of sodium dodecyl benzene sulfonate in 20g of deionized water, dropwise adding 12g of methacrylic acid, 40g of hydroxyethyl methacrylate and 26g of butyl acrylate under stirring at the rotating speed of 1000rpm, finishing dropping within 0.5h, and stirring for 1h after finishing dropping to prepare a shell layer pre-emulsion;

(3) adding 40g of deionized water and 0.2g of sodium dodecyl benzene sulfonate into a four-neck flask provided with a stirrer, a condenser pipe and a two-neck connecting pipe under the protection of nitrogen, uniformly stirring, heating to 80 ℃ in a constant-temperature water bath kettle, dropwise adding 57g of the nuclear layer pre-emulsion prepared in the step (1) and 3g of 5 wt% ammonium persulfate aqueous solution, and finishing dropwise adding within 3h to prepare a nuclear layer emulsion;

(4) and (3) taking 40g of the core-layer emulsion prepared in the step (3), dropwise adding 50g of the shell-layer pre-emulsion prepared in the step (2) and 3g of a 5 wt% ammonium persulfate aqueous solution at the temperature of 80 ℃, keeping the temperature for 1h under the temperature control of 80 ℃, finishing the reaction, adding 2g of N, N-dimethylethanolamine and 5g of deionized water, adjusting the pH value to 4-7, filtering, and discharging to obtain the self-thickening acrylic emulsion.

Before the self-thickening acrylic emulsion prepared by the embodiment is used for preparing the pearlescent flash paint, deionized water is used in advance to dilute the solid content of the self-thickening acrylic emulsion to 20 wt%, and ammonia water is used for adjusting the pH value to 8-8.5, so that the self-thickening acrylic emulsion can be used as a raw material for preparing the pearlescent flash paint.

Example 2 preparation of self-thickening acrylic emulsions

(1) Dissolving 3g of sodium dodecyl benzene sulfonate in 30g of deionized water, dropwise adding 45g of methyl methacrylate and 22g of butyl acrylate under stirring at the rotating speed of 800rpm, finishing dropping within 0.5h, and stirring for 1h after finishing dropping to prepare a core layer pre-emulsion;

(2) dissolving 3g of sodium dodecyl benzene sulfonate in 30g of deionized water, dropwise adding 6g of methacrylic acid, 40g of hydroxyethyl methacrylate and 21g of butyl acrylate under stirring at the rotating speed of 800rpm, finishing dropping within 0.5h, and stirring for 1h after finishing dropping to prepare a shell layer pre-emulsion;

(3) adding 30g of deionized water and 0.3g of sodium dodecyl benzene sulfonate into a four-neck flask provided with a stirrer, a condenser pipe and a two-neck connecting pipe under the protection of nitrogen, uniformly stirring, heating to 85 ℃ in a constant-temperature water bath kettle, dropwise adding 65g of the nuclear layer pre-emulsion prepared in the step (1) and 5g of 5 wt% ammonium persulfate aqueous solution, and finishing dropwise adding within 2h to prepare a nuclear layer emulsion;

(4) and (3) taking 25g of the core-layer emulsion prepared in the step (3), dropwise adding 65g of the shell-layer pre-emulsion prepared in the step (2) and 5g of a 5 wt% ammonium persulfate aqueous solution at the temperature of 85 ℃, keeping the temperature at 85 ℃ within 3h, keeping the temperature for 1h, reacting, adding 2g of N, N-dimethylethanolamine and 3g of deionized water, adjusting the pH value to 4-7, filtering, and discharging to obtain the self-thickening acrylic emulsion.

Example 3 preparation of self-thickening acrylic emulsions

(1) Dissolving 5g of sodium dodecyl benzene sulfonate in 25g of deionized water, dropwise adding 55g of methyl methacrylate and 15g of butyl acrylate under stirring at the rotating speed of 1500rpm, finishing dropping within 0.5h, and stirring for 1h after finishing dropping to prepare a nuclear layer pre-emulsion;

(2) dissolving 5g of sodium dodecyl benzene sulfonate in 25g of deionized water, dropwise adding 8g of methacrylic acid, 32g of hydroxyethyl methacrylate and 30g of butyl acrylate under stirring at the rotating speed of 1500rpm, finishing dropping within 0.5h, and stirring for 1h after finishing dropping to prepare a shell layer pre-emulsion;

(3) adding 55g of deionized water and 0.4g of sodium dodecyl benzene sulfonate into a four-neck flask provided with a stirrer, a condenser pipe and a two-neck connecting pipe under the protection of nitrogen, uniformly stirring, heating to 80 ℃ in a constant-temperature water bath kettle, dropwise adding 43g of the nuclear layer pre-emulsion prepared in the step (1) and 2g of 5 wt% ammonium persulfate aqueous solution, and finishing dropwise adding within 3 hours to prepare a nuclear layer emulsion;

(4) and (3) taking 35g of the core-layer emulsion prepared in the step (3), dropwise adding 55g of the shell-layer pre-emulsion prepared in the step (2) and 2g of a 5 wt% ammonium persulfate aqueous solution at the temperature of 85 ℃, keeping the temperature at 85 ℃ within 3h, keeping the temperature for 1h, reacting, adding 2g of N, N-dimethylethanolamine and 6g of deionized water, adjusting the pH value to 4-7, filtering, and discharging to obtain the self-thickening acrylic emulsion.

Example 4 preparation of mica-pearlescent powder Dispersion syrup

The mica pearl powder dispersing pulp comprises the following components in percentage by mass: 45% of T60-21 interference red pearl powder, 45% of TEGO-6553%, 84214% of AQUATIX, 6% of pentaerythritol palmitate and 42% of ethylene glycol butyl ether.

Preparation: mixing ethylene glycol monobutyl ether, pentaerythritol palmitate, AQUATIX 8421 and TEGO-655 according to the formula amount, stirring for 10 minutes, then adding T60-21 interference red pearl powder according to the formula amount, and stirring for 5 minutes to obtain the mica pearl powder dispersion slurry.

Example 5 preparation of mica-pearlescent powder Dispersion syrup

The mica pearl powder dispersing pulp comprises the following components in percentage by mass: 40% of T60-20 interference yellow pearl powder, 40% of EFKA-50565%, 84216% of AQUATIX, 4% of pentaerythritol palmitate and 45% of ethylene glycol butyl ether.

Preparation: mixing ethylene glycol monobutyl ether, pentaerythritol palmitate, AQUATIX 8421 and EFKA-5056 according to the formula amount, stirring for 8 minutes, then adding T60-20 interference yellow pearl powder according to the formula amount, and stirring for 4 minutes to obtain mica pearl powder dispersion slurry.

Example 6 preparation of mica-pearlescent powder Dispersion syrup

The mica pearl powder dispersing pulp comprises the following components in percentage by mass: 50% of T60-23 interference blue pearl powder, 50% of EFKA-50564%, 84212% of AQUATIX, 4% of pentaerythritol palmitate and 40% of ethylene glycol butyl ether.

Preparation: mixing ethylene glycol monobutyl ether, pentaerythritol palmitate, AQUATIX 8421 and EFKA-5056 according to the formula amount, stirring for 9 minutes, then adding T60-23 interference blue pearl powder according to the formula amount, and stirring for 5 minutes to obtain the mica pearl powder dispersion slurry.

EXAMPLE 7 preparation of aqueous interference-type pearlescent flashing paint

The waterborne interference pearlescent flashing paint comprises the following components in percentage by mass as shown in the following table 1:

TABLE 1 aqueous interference pearlescent flashing paints of different formulations

Preparation:

(1) under the stirring speed of 500 r/min, adding Bayhydro 2621, self-thickening acrylic emulsion, Cymel325, ASE60, organic bentonite and MA-95 into water in sequence, and stirring for 25 min;

(2) and (2) adding the mica pearl powder dispersion slurry, propylene glycol methyl ether acetate and n-bromopropane into the material obtained in the step (1), stirring at 50 revolutions per minute for 5 minutes to obtain the mica pearl powder.

The performance of the waterborne interference pearlescent flashing paint prepared by the formulas is detected as follows:

the substrate is a cold-rolled steel plate, after degreasing, cleaning and drying, the sample plate manufacturing is carried out according to the process flow requirement of 2C1B, the thickness of the pearlescent flash paint is 14 micrometers, the thickness of the finishing varnish is 40 micrometers, wherein the pearlescent flash paint is prepared by the formula 1-6 of the embodiment 7, the varnish is solvent type amino polyester baking paint, and the specific detection method comprises the following steps:

the viscosity is detected by adopting an NDJ-1 rotational viscometer according to GB/T1723-1993, and the thixotropic value of the coating is the viscosity ratio of the coating at 6r/min and 60r/min of the rotational viscometer;

flash index: testing with a scintillation tester, X-Rite inc. grandville, MI;

the gloss was measured according to GB/T9754-2007;

the adhesion is determined according to GB/T9286 1998 test of marking out paint films of paints and varnishes;

the hardness is tested according to GB/T6739-;

impact resistance was tested as GB/T1732-1993;

the water resistance is tested according to GB/T1733 + 1993 paint film water resistance determination method;

the alkali resistance and the acid resistance are tested according to the regulation of the A method of GB/T9274-1988, determination of alkali resistance of coating;

the artificial weathering resistance is tested according to GB/T1865-2009 artificial weathering and artificial radiation exposure for colored paint and varnish;

the salt spray resistance is determined according to GB/T1771-2007 determination of neutral salt spray resistance of colored paint and varnish;

the results are shown in Table 2:

TABLE 2 quality index of aqueous interference pearlescent flashing paint

The result shows that the waterborne interference pearlescent flashing paint provided by the invention has a higher thixotropic value, is beneficial to construction, and has high flashing index and glossiness and obvious pearlescent effect; in addition, the paint has excellent mechanical properties such as adhesive force, hardness, impact resistance and the like, and has good various weather resistance properties.

EXAMPLE 8 preparation of aqueous interference-type pearlescent flashing paint

Example 8 is a feeding formula for changing the content of each substance under the condition that the variety of each substance in the formula 1 of example 7 is not changed, and the waterborne interference pearlescent flashing paint is prepared according to the process of example 7 as shown in the following table 3.

TABLE 3 aqueous interference pearlescent flashing paints of different formulations

The performances of the waterborne interference type pearlescent flashing paint prepared by the formulas 7-9 are shown in table 4, and the comparison with the performances in table 2 shows that when the contents of all substances in the formula of the pearlescent flashing paint exceed the ranges disclosed by the invention, the performances of the waterborne interference type pearlescent flashing paint are obviously reduced, especially when the ratio of the waterborne polyurethane dispersion and the self-thickening acrylic emulsion exceeds the range disclosed by the invention, the performance detection result of the pearlescent flashing paint is greatly influenced.

TABLE 4 quality index of aqueous interference pearlescent flashing paint

Comparative examples 1-2 preparation of aqueous interference type pearlescent flash paint

Comparative example 1 an aqueous interference pearlescent flash paint differs from formulation 1 of example 7 only in that: the self-thickening acrylic emulsion of the invention is replaced by a common water-based acrylic emulsion (Cosimva Bayhydrol A2457) on the market, and the other components and the content are unchanged, and the water-based interference pearlescent flashing paint is prepared according to the preparation method of the example 7.

Comparative example 2 the aqueous interference pearlescent flash paint differs from formulation 1 of example 7 only in that: the aqueous interference pearlescent flashing paint is prepared according to the preparation method of the example 7 without the thickener and correspondingly increasing the content of the self-thickening acrylic emulsion, and the other components and the content are unchanged.

The quality indexes of the aqueous interference pearlescent flash paints of comparative examples 1 to 2 are shown in Table 5.

TABLE 5 quality index of water-based interference pearlescent flashing paint

The results show that the touch value, the flashing index, the gloss and the weather resistance of various aspects of the waterborne interference pearlescent flashing paint prepared by replacing the self-thickening acrylic emulsion with the common waterborne acrylic emulsion on the market are deteriorated; the formula does not contain a thickening agent, only uses the self-thickening acrylic emulsion as a thixotropic agent, slightly influences the weather resistance of the prepared waterborne interference pearlescent flashing paint in all aspects, but obviously reduces the touch value, the flashing index and the gloss of the pearlescent flashing paint.

Comparative example 3 preparation of aqueous interference type pearlescent flash paint

Comparative example 3 an aqueous interference pearlescent flashing paint, comprising the following components in percentage by mass:

self-thickening acrylic emulsions

(prepared in example 1, diluted to a solid content of 20 wt% and a pH of 8 to 8.5) 30%

Comparative example 3 the aqueous interference type pearlescent flash paint is different from the formulation 1 of example 7 in that the raw material of the mica pearlescent powder dispersion slurry is directly added to the pearlescent paint formulation and pentaerythritol palmitate and a diluent are not added, and accordingly the water content is increased, and the preparation method is referred to example 7.

Comparative example 3 the quality index of the aqueous interference pearlescent flashing paint is shown in table 6.

TABLE 6 quality index of water-based interference pearlescent flashing paint

Index (I)	Comparative example 3
		Appearance of coating film	Low luster, loss of gloss, color difference, blooming and graining
Value of touch	4.5
		Index of flash	13.0
60 degree gloss	75
		Adhesion force	0
Hardness of	2H
		Impact resistance/cm	50
Water resistance/h	240
		Alkali resistance/h	42
Acid resistance/h	36
		Resistance to weathering by Artificial climate/h	1300
Salt spray resistance per hour	700

The result shows that the raw material of the mica pearl powder dispersion slurry is directly added into the formula of the pearl paint, and no pentaerythritol palmitate or diluent is added, the prepared pearl flashing paint film has low gloss, and has the phenomena of light loss, color difference, flowering and graining, and the glittering index and the gloss are reduced, which is speculated to be caused by that under the condition of lacking the pentaerythritol palmitate and the diluent, the 2C1B coating process is used, the ground color pearl paint cannot reach dry touch before the finish paint is coated, the pearl pigment generates casting under the action of the finish paint solvent, and further influences various weather resistance of the pearl paint.

The above is only a preferred embodiment of the present invention, and it should be noted that the above preferred embodiment should not be considered as limiting the present invention, and the protection scope of the present invention should be subject to the scope defined by the claims. It will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the spirit and scope of the invention, and these modifications and adaptations should be considered within the scope of the invention.

Claims

1. The waterborne interference pearlescent flashing paint for the automobile is characterized by comprising the following components in percentage by mass: 15-25% of mica pearl powder dispersion slurry, 5-10% of an aqueous polyurethane dispersion, 25-35% of a self-thickening acrylic emulsion, 2-4% of an aqueous amino resin, 1-3% of a thickening agent, 2-4% of an amine neutralizing agent, 2-5% of a diluting agent and 25-30% of water;

the mica pearl powder dispersion slurry comprises the following components in percentage by mass: 40-50% of mica titanium pearl powder, 2-5% of wetting dispersant, 2-6% of rheological modified wax emulsion, 4-8% of pentaerythritol palmitate and 40-45% of ethylene glycol butyl ether;

the diluent consists of propylene glycol methyl ether acetate and n-bromopropane in a mass ratio of 1 (0.5-1);

the thickening agent is composed of an alkali swelling thickening agent and organic bentonite according to a mass ratio of 1 (0.1-0.2).

2. The aqueous interference pearlescent flash paint for automobile according to claim 1, wherein the wetting and dispersing agent is digao TEGO-655 or Effka EFKA-5056; the rheology modified wax emulsion is Picker AQUATIX 8421.

3. The aqueous interference pearlescent flash paint for automobile according to claim 1, wherein the preparation of the mica pearlescent powder dispersion slurry comprises the following steps: mixing ethylene glycol monobutyl ether, pentaerythritol palmitate, the rheology modified wax emulsion and the wetting dispersant according to the formula amount, stirring for 8-10 minutes, then adding the mica titanium pearl powder according to the formula amount, and stirring for 4-5 minutes to obtain the mica pearl powder dispersion slurry.

4. The aqueous interference pearlescent flash paint for automobile according to claim 1, wherein the alkali swelling thickener is Rohm and Hass ASE 60.

5. The aqueous interference pearlescent flash paint for automobile according to claim 1, wherein the amine neutralizer is Haimax MA-95.

6. A method for preparing the aqueous interference type pearlescent flash paint for automobile of claim 1, which comprises the steps of: