WO2025000161A1 - Effect pigment building coating having color and storage stability and preparation method therefor - Google Patents

Abstract

An effect pigment building coating having color and storage stability and a preparation method therefor. The preparation method for the effect pigment building coating comprises the following steps: mixing natural mica flakes modified by silicon dioxide and iron oxide, silicon dioxide aerogel, and cyclohexane, and dispersing same uniformly; adding dimer acid and polycarbonate diol for reaction under the action of a catalyst, and when an acid value of a system reaches 7-10 mg KOH/g, stopping the reaction and adding methyl ethyl ketone, stirring uniformly; and then, adding an acrylate polymer dispersant emulsion, a polyurethane-modified acrylic resin, and water, and dispersing same uniformly. The effect pigment building coating prepared by the preparation method not only maintains the color for a long time but also exhibits excellent storage stability, and has wide application prospects.

Description

A color and storage-stable effect pigment architectural coating and preparation method thereof Technical Field

The invention relates to the field of coatings, in particular to a color and storage-stable effect pigment architectural coating and a preparation method thereof.

Background Art

Effect pigment paint is a kind of metallic glitter paint, which refers to a type of paint with a granular glittering effect made with transparent organic pigments or flake effect pigments such as aluminum powder, pearl powder, copper and gold powder, etc. After painting, under the irradiation of light, the flake pigments in the paint film shine and glitter, showing a strong metallic texture, and with the change of observation angle, it presents rich layers of light and dark and tonal changes, giving people a luxurious and gorgeous visual impact, thus becoming the mainstream of topcoat coating, and its usage has exceeded 70% of the demand for topcoat coating.

Although effect pigment coatings have attractive application prospects, after being used outdoors for a period of time, they will cause color distortion due to aging and other reasons. In addition, the storage stability of effect pigment architectural coatings is poor, which has always restricted the application of this coating.

The present invention adopts modified natural mica flakes, which are coated with silica aerogel and then added with a specific dispersant system, which not only ensures the color stability of the coating during long-term use, but also greatly improves the storage stability of the coating due to the presence of the dispersion system, and the coating has good freeze-thaw performance.

Summary of the invention

The purpose of the present invention is to provide a color and storage-stable effect pigment architectural coating and a preparation method thereof in order to overcome the defects of the above-mentioned prior art. The coating obtained by the preparation method not only has a long-lasting color, but also has good storage stability, and has a wide range of application prospects.

The present invention solves the above technical problems through the following technical solutions:

A method for preparing an architectural coating containing effect pigments comprises the following steps:

(1) Mixing natural mica sheets modified with silica and iron oxide, silica aerogel and cyclohexane and dispersing them evenly;

(2) Add dimer acid and polycarbonate diol and react under the action of the catalyst. When the acid value of the system reaches 7-10 mg KOH/g, stop the reaction and add methyl ethyl ketone and stir evenly;

(3) After adding acrylic polymer dispersant emulsion, polyurethane modified acrylic resin and water, the mixture is evenly dispersed. The acrylic polymer dispersant emulsion is prepared by the following method: in a solvent, methyl methacrylate, hydroxyethyl methacrylate and 1,6-hexanediol dimethacrylate are polymerized under the action of an initiator and a surfactant to obtain an acrylic polymer dispersant emulsion.

The natural mica flakes modified with silicon dioxide and iron oxide are prepared by the following method: mixing the natural mica flakes with water, adding the orthosilicic acid solution, stirring for reaction, and filtering to obtain the first reactant; placing the first reactant in a vapor deposition reactor, and performing iron red vapor diffusion and penetration treatment under vacuum conditions.

The time of the gas phase diffusion infiltration treatment is preferably 60 to 90 minutes.

Wherein, it is preferred to carry out drying and calcination after the gas phase diffusion infiltration treatment; the drying temperature is preferably 120-140°C, and the calcination temperature is preferably 500-550°C.

In step (2), the catalyst may be a tin compound, preferably dibutyltin oxide or tin isooctanoate.

In step (3), the solvent is preferably deionized water.

In step (3), the initiator is preferably a peroxide initiator, more preferably ammonium persulfate or dibenzoyl peroxide.

In step (3), the surfactant is preferably AEROSOL EF-810 surfactant purchased from Solvay.

In step (3), the polyurethane modified acrylic resin is preferably prepared by the following method: mixing hydroxy acrylate and isocyanate and heating them to react to obtain a polyurethane prepolymer; adding an organic solvent and polymerizing the polyurethane prepolymer with methyl methacrylate to obtain the polyurethane modified acrylic resin.

The invention also provides architectural coating containing effect pigments prepared by the preparation method.

In a preferred embodiment of the present invention, the architectural coating may further include various additives.

If an auxiliary agent is included, it is added in step (3).

Compared with the prior art, the present invention has the following beneficial effects: the present invention adopts modified natural mica flakes, which are coated with silica aerogel and then added with a specific dispersant system, which not only ensures the color stability of the coating during long-term use, but also greatly improves the storage stability of the coating due to the presence of the dispersion system, and the coating has good freeze-thaw properties.

Implementation

The present invention is described in detail below with reference to specific embodiments.

Storage stability test: Store the pigment at 20℃ and 40℃ for 10 weeks to observe whether there is any sedimentation or deterioration, and to observe the color change of the coating after drying.

Freeze-thaw stability test method: First, the pH of the pigment (measured at 23°C) and its viscosity at shear loads of 10s-1, 100s-1 and 1000s-1 were determined [measured at 23°C using a rotational viscometer (Rheolab QC equipment from Anton Paar, with C-LTD80/QC adjustment system)]. 200 g of the corresponding pigment was then stored at -18°C for 8 hours in a tightly sealed glass bottle and subsequently kept at room temperature for 16 hours. This procedure was repeated 4 more times. The pH and viscosity were then determined again, and the sedimentation characteristics of the pigment were evaluated.

Example

Preparation of natural mica flakes modified with silicon dioxide and iron oxide: natural mica flakes with a particle size of 10-15 μm are mixed with water, and then the orthosilicic acid solution is slowly added, stirred for reaction, and the first reactant is obtained by suction filtration; the first reactant is placed in a vapor deposition reactor, and subjected to iron red vapor diffusion and penetration treatment for 70 minutes under vacuum conditions, and then dried at 120°C for 1 hour and calcined at 500°C for 2 hours.

The architectural coating containing effect pigments in this embodiment is prepared by the following steps:

(1) Mixing the natural mica flakes modified with silica and iron oxide obtained above, the silica aerogel and cyclohexane, and stirring and dispersing them uniformly;

(2) Add dimer acid and polycarbonate diol, react under the action of dibutyltin oxide catalyst. When the acid value of the system reaches 8 mg KOH/g, stop the reaction and add methyl ethyl ketone and stir evenly;

(3) Add acrylic polymer dispersant emulsion, polyurethane modified acrylic resin and water and disperse evenly.

The acrylic polymer dispersant emulsion is prepared by the following method: in a solvent (deionized water), methyl methacrylate, hydroxyethyl methacrylate and 1,6-hexanediol dimethacrylate are polymerized at 70° C. under the action of an initiator (ammonium persulfate) and a surfactant (AEROSOL EF-810 of Solvay) to obtain the acrylic polymer dispersant emulsion; wherein the mass ratio of methyl methacrylate, hydroxyethyl methacrylate and 1,6-hexanediol dimethacrylate is 2:1:1.

The polyurethane modified acrylic resin is prepared by the following method: hydroxy acrylate and isocyanate are mixed in a mass ratio of 1:1.2 and heated to react to obtain a polyurethane prepolymer; an organic solvent (propylene glycol ethyl ether) is added, and the polyurethane prepolymer and methyl methacrylate are polymerized for 3 hours under the initiation of ammonium persulfate; the isocyanate is diphenylmethane diisocyanate.

After the pigment of this example was stored at 20° C. and 40° C. for 10 weeks, no sedimentation or deterioration was observed, the pH value remained substantially unchanged, and the color of the coating after drying did not change.

After the above freeze-thaw cycle test, the test results are as follows:

.

Example

Preparation of natural mica flakes modified with silicon dioxide and iron oxide: natural mica flakes with a particle size of 10-15 μm are mixed with water, and then the orthosilicic acid solution is slowly added, stirred for reaction, and the first reactant is obtained by suction filtration; the first reactant is placed in a vapor deposition reactor, and subjected to iron red vapor diffusion and penetration treatment for 80 minutes under vacuum conditions, and then dried at 130°C for 1 hour and calcined at 550°C for 2 hours.

The architectural coating containing effect pigments in this embodiment is prepared by the following steps:

(1) Mixing the natural mica flakes modified with silica and iron oxide obtained above, the silica aerogel and cyclohexane, and stirring and dispersing them uniformly;

(2) Add dimer acid and polycarbonate diol, react under the action of tin isooctanoate catalyst, and when the acid value of the system reaches 10 mg KOH/g, stop the reaction and add methyl ethyl ketone, stirring evenly;

(3) Add acrylic polymer dispersant emulsion, polyurethane modified acrylic resin and water and disperse evenly.

The acrylic polymer dispersant emulsion is prepared by the following method: in a solvent (deionized water), methyl methacrylate, hydroxyethyl methacrylate and 1,6-hexanediol dimethacrylate are polymerized at 80° C. under the action of an initiator (ammonium persulfate) and a surfactant (AEROSOL EF-810 of Solvay) to obtain the acrylic polymer dispersant emulsion; wherein the mass ratio of methyl methacrylate, hydroxyethyl methacrylate and 1,6-hexanediol dimethacrylate is 1:1:1.

The polyurethane modified acrylic resin is prepared by the following method: hydroxy acrylate and isocyanate are mixed in a mass ratio of 1:1.5 and heated to react to obtain a polyurethane prepolymer; an organic solvent (propylene glycol ethyl ether) is added, and the polyurethane prepolymer and methyl methacrylate are polymerized for 3 hours under the initiation of ammonium persulfate; the isocyanate is hexamethylene diisocyanate.

After the pigment of this example was stored at 20° C. and 40° C. for 10 weeks, no sedimentation or deterioration was observed, the pH value remained substantially unchanged, and the color of the coating after drying did not change.

After the above freeze-thaw cycle test, the test results are as follows:

.

Comparative Example 1

In step (2) of the preparation method of this example, when the acid value of the system reaches 4 mg KOH/g, the reaction is stopped, and the other preparation methods and parameter conditions are the same as those in Example 1 to prepare the architectural coating. Its performance is tested.

After the pigment of this example was stored at 20°C for 10 weeks, no sedimentation or deterioration was observed, the pH value remained basically unchanged, and the color of the coating after drying did not change; however, after storage at 40°C for 10 weeks, a small amount of sedimentation was observed, the color of the coating after drying became dim, and the brightness was significantly reduced.

After the above freeze-thaw cycle test, the test results are as follows:

.

Comparative Example 2

In step (2) of the preparation method of this example, polycaprolactone diol is used to replace polycarbonate diol, and the other preparation methods and parameter conditions are the same as those in Example 1 to prepare the architectural coating. The performance of the coating is tested.

After the pigment of this example was stored at 20°C for 10 weeks, no sedimentation or deterioration was observed, the pH value remained basically unchanged, and the color of the coating after drying did not change; however, after storage at 40°C for 10 weeks, obvious sedimentation was observed, the color of the coating after drying became dull, and the brightness was significantly reduced.

After the above freeze-thaw cycle test, the test results are as follows:

.

From the above comparison, it can be seen that the coatings of Comparative Examples 1 and 2 are prone to sedimentation and deterioration under high temperature storage conditions, and the coating color will also become dim, and the brightness will be significantly reduced; the viscosity increases significantly after freeze-thaw cycles, which greatly affects the product quality. However, the coating obtained in the embodiment of the present invention has no obvious change, and the viscosity does not increase significantly after freeze-thaw cycles, indicating that the coating of the present invention has good freeze-thaw performance.

It must be emphasized that the above detailed description is a specific description of a feasible embodiment of the present invention, but the embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not deviate from the technical spirit of the present invention should be included in the patent scope of the present invention.

Claims (10)

A method for preparing an architectural coating containing effect pigments comprises the following steps: (1) Mixing natural mica sheets modified with silica and iron oxide, silica aerogel and cyclohexane and dispersing them evenly; (2) Add dimer acid and polycarbonate diol and react under the action of the catalyst. When the acid value of the system reaches 7-10 mg KOH/g, stop the reaction and add methyl ethyl ketone and stir evenly; (3) After adding acrylic polymer dispersant emulsion, polyurethane modified acrylic resin and water, the mixture is evenly dispersed. The acrylic polymer dispersant emulsion is prepared by the following method: in a solvent, methyl methacrylate, hydroxyethyl methacrylate and 1,6-hexanediol dimethacrylate are polymerized under the action of an initiator and a surfactant to obtain an acrylic polymer dispersant emulsion. The preparation method as described in claim 1 is characterized in that the natural mica flakes modified with silicon dioxide and iron oxide are prepared by the following method: after mixing the natural mica flakes with water, adding the orthosilicic acid solution, stirring the reaction, and filtering to obtain the first reactant; placing the first reactant in a vapor deposition reactor, and performing iron red vapor diffusion and penetration treatment under vacuum conditions. The preparation method according to claim 2 is characterized in that the time of the gas phase diffusion infiltration treatment is preferably 60 to 90 minutes. The preparation method according to claim 2 is characterized in that drying and calcination are carried out after the gas phase diffusion infiltration treatment; the drying temperature is preferably 120~140°C, and the calcination temperature is preferably 500~550°C. The preparation method according to claim 1, characterized in that in step (2), the catalyst is a tin compound, preferably dibutyltin oxide or tin isooctanoate. The preparation method according to claim 1, characterized in that in step (3), the solvent is deionized water. The preparation method according to claim 1, characterized in that in step (3), the initiator is a peroxide initiator, preferably ammonium persulfate or dibenzoyl peroxide. The preparation method according to claim 1, characterized in that in step (3), the surfactant is AEROSOL EF-810 surfactant purchased from Solvay. The preparation method according to claim 1, characterized in that in step (3), the polyurethane modified acrylic resin is preferably prepared by the following method: mixing hydroxy acrylate and isocyanate and heating them to react to obtain a polyurethane prepolymer; adding an organic solvent and polymerizing the polyurethane prepolymer with methyl methacrylate to obtain. An architectural coating containing effect pigments prepared by the preparation method according to any one of claims 1 to 9.