Effect pigment building coating having color and storage stability and preparation method therefor

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

[0001] The present 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

[0002] Effect pigment paint is a type of metallic glitter paint, which refers to a type of paint with a granular shimmering effect made from transparent organic pigments or flake effect pigments such as aluminum powder, pearl powder, copper and gold powder, etc. After painting, under the illumination of light, the flake pigments in the paint film shimmer and sparkle, presenting a strong metallic texture. It also presents rich layers of light and dark and tonal changes as the observation angle changes, giving people a luxurious and gorgeous visual impact. Therefore, it has become the mainstream of topcoat coating, and its usage has exceeded 70% of the topcoat coating demand.

[0003] Although effect pigment coatings have attractive application prospects, after a period of outdoor use, 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.

[0004] The present invention adopts modified natural mica sheets, which are coated with silica aerogel and then added with a specific dispersant system. This 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. Summary of the Invention

[0005] The present invention aims to overcome the aforementioned shortcomings of the prior art by providing a color- and storage-stable effect pigment architectural coating and a method for its preparation. The coating produced by this method not only maintains its color over time but also exhibits excellent storage stability, promising broad application prospects.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] A method for preparing an architectural coating containing effect pigments comprises the following steps:

[0008] (1) Mixing natural mica sheets modified with silica and iron oxide, silica aerogel and cyclohexane and dispersing them evenly;

[0009] (2) Add dimer acid and polycarbonate diol and react under the action of catalyst. When the acid value of the system reaches 7~10mg KOH / g, stop the reaction and add methyl ethyl ketone and stir evenly;

[0010] (3) After adding acrylic polymer dispersant emulsion, polyurethane modified acrylic resin and water, disperse them evenly; 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.

[0011] 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 an orthosilicic acid solution, stirring for reaction, and filtering to obtain a first reactant; placing the first reactant in a vapor deposition reactor, and performing iron red vapor diffusion and infiltration treatment under vacuum conditions.

[0012] The time for the gas phase diffusion infiltration treatment is preferably 60 to 90 minutes.

[0013] After the gas phase diffusion infiltration treatment, it is preferably dried and calcined; the drying temperature is preferably 120-140°C, and the calcination temperature is preferably 500-550°C.

[0014] In step (2), the catalyst may be a tin compound, preferably dibutyltin oxide or tin isooctanoate.

[0015] In step (3), the solvent is preferably deionized water.

[0016] In step (3), the initiator is preferably a peroxide initiator, more preferably ammonium persulfate or dibenzoyl peroxide.

[0017] In step (3), the surfactant is preferably AEROSOL EF-810 surfactant purchased from Solvay.

[0018] 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.

[0019] The present invention also provides architectural coatings containing effect pigments prepared by the above preparation method.

[0020] In a preferred embodiment of the present invention, the architectural coating may further include various additives.

[0021] If an adjuvant is included, it is added in step (3).

[0022] 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 Method

[0023] The present invention is described in detail below with reference to specific embodiments.

[0024] Storage stability test: Store the pigment at 20℃ and 40℃ for 10 weeks to observe whether there is any sedimentation or deterioration, and observe the color change of the coating after drying.

[0025] Freeze-thaw stability test method: First, the pigment's pH (measured at 23°C) and viscosity at shear loads of 10 s⁻¹, 100 s⁻¹, and 1000 s⁻¹ were determined using a rotational viscometer (Rheolab QC instrument from Anton Paar, with C-LTD80 / QC control system) at 23°C. 200 g of the respective pigment was then stored in a tightly sealed glass bottle at -18°C for 8 hours and then at room temperature for 16 hours. This procedure was repeated four more times. The pH and viscosity were then measured again, and the pigment's sedimentation characteristics were evaluated. Example

[0026] 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 an orthosilicic acid solution is slowly added thereto. The mixture is stirred for reaction and filtered to obtain a first reactant. The first reactant is placed in a vapor deposition reactor and subjected to iron red vapor diffusion and infiltration treatment under vacuum conditions for 70 minutes. The reactant is then dried at 120°C for 1 hour and calcined at 500°C for 2 hours.

[0027] The architectural coating containing effect pigments of this embodiment was prepared by the following steps:

[0028] (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;

[0029] (2) Add dimer acid and polycarbonate diol and react under the action of catalyst dibutyltin oxide. When the acid value of the system reaches 8 mg KOH / g, stop the reaction and add methyl ethyl ketone and stir evenly;

[0030] (3) Add acrylic polymer dispersant emulsion, polyurethane modified acrylic resin and water and disperse evenly.

[0031] 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 subjected to a polymerization reaction at 70° C. under the action of an initiator (ammonium persulfate) and a surfactant (AEROSOL EF-810 from 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.

[0032] 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.

[0033] 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.

[0034] After the freeze-thaw cycle test described above, the test results are as follows:

[0035] . Example

[0036] 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 an orthosilicic acid solution is slowly added. The mixture is stirred for reaction and filtered to obtain a first reactant. The first reactant is placed in a vapor deposition reactor and subjected to iron red vapor diffusion and infiltration treatment under vacuum conditions for 80 minutes, followed by drying at 130°C for 1 hour and calcining at 550°C for 2 hours.

[0037] The architectural coating containing effect pigments of this embodiment was prepared by the following steps:

[0038] (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;

[0039] (2) Add dimer acid and polycarbonate diol and react under the action of tin isooctanoate catalyst. When the acid value of the system reaches 10 mg KOH / g, stop the reaction and add methyl ethyl ketone and stir evenly;

[0040] (3) Add acrylic polymer dispersant emulsion, polyurethane modified acrylic resin and water and disperse evenly.

[0041] 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 subjected to a polymerization reaction at 80° C. under the action of an initiator (ammonium persulfate) and a surfactant (AEROSOL EF-810 from 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.

[0042] 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.

[0043] 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.

[0044] After the freeze-thaw cycle test described above, the test results are as follows:

[0045] .

[0046] Comparative Example 1

[0047] In step (2) of this preparation method, when the acid value of the system reached 4 mg KOH / g, the reaction was stopped. The other preparation methods and parameters were the same as those in Example 1 to prepare the architectural coating. Its performance was tested.

[0048] 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, and the color of the coating after drying became dull and the brightness was significantly reduced.

[0049] After the freeze-thaw cycle test described above, the test results are as follows:

[0050] .

[0051] Comparative Example 2

[0052] In step (2) of the preparation method of this example, polycarbonate diol was replaced by polycaprolactone diol. The other preparation methods and parameters were the same as those in Example 1 to prepare an architectural coating. Its performance was tested.

[0053] 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 dim, and the brightness was significantly reduced.

[0054] After the freeze-thaw cycle test described above, the test results are as follows:

[0055] .

[0056] The above comparison shows that the coatings of Comparative Examples 1 and 2 easily deteriorate under high-temperature storage conditions, and the coating color becomes dull and the brightness is significantly reduced. The viscosity increases significantly after freeze-thaw cycles, significantly affecting product quality. However, the coatings obtained in the examples of the present invention show no significant changes, and the viscosity does not increase significantly after freeze-thaw cycles, indicating that the coatings of the present invention have good freeze-thaw performance.

[0057] 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.

[0058]

Claims

1. A method for preparing an architectural coating containing effect pigments, comprising 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.

2. The preparation method according to claim 1, characterized in that The natural mica flakes modified by 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.

3. The preparation method according to claim 2, characterized in that: The time of the gas phase diffusion infiltration treatment is preferably 60 to 90 minutes.

4. The preparation method according to claim 2, characterized in that: After the gas phase diffusion infiltration treatment, drying and calcination are performed; the drying temperature is preferably 120-140°C, and the calcination temperature is preferably 500-550°C.

5. 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.

6. The preparation method according to claim 1, characterized in that: In step (3), the solvent is deionized water.

7. 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.

8. The preparation method according to claim 1, characterized in that: In step (3), the surfactant is AEROSOL EF-810 surfactant purchased from Solvay.

9. 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 the polyurethane modified acrylic resin.

10. An architectural coating containing effect pigments prepared by the preparation method according to any one of claims 1 to 9.

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