Magnesium potassium ion-containing architectural decorative coating and preparation method thereof

Abstract

The application discloses a kind of magnesium potassium ion building decoration coatings and preparation method thereof, belong to the technical field of coating composition, the coating includes thickening agent, water, anhydrous magnesium citrate, potassium citrate, dispersant, pigment, coordination functional adjuvant, defoaming agent, styrene-acrylic emulsion, film-forming aid, emulsifier and leveling agent.Firstly, the thickening agent is dissolved, then the magnesium potassium salt is dissolved, and then the dispersant, pigment, functional adjuvant and defoaming agent are added and dispersed at high speed.After cooling, the styrene-acrylic emulsion is added, and then the pre-emulsified film-forming aid and emulsifier are added.Finally, the leveling agent and defoaming agent are added, and then sieved to obtain the product.Compared with the prior art, the application effectively inhibits the crystallization and precipitation of magnesium salt during storage, has low viscosity change rate, high storage stability, and can form a dense carbon layer or ceramic layer during combustion, has low smoke density grade, excellent fireproofing, heat insulation and heat preservation performance, and can be applied to the decoration and protection fields of ships, high-speed rails, ocean engineering and other harsh decoration and stability requirements.

Description

Technical Field

[0001] This invention relates to the field of coating composition technology, and in particular to a magnesium-potassium ion-containing architectural decorative coating and its preparation method. Background Technology

[0002] Architectural coatings are essential materials for interior and exterior wall decoration and protection. With increasingly stringent environmental regulations and rising demands for residential safety, water-based coatings are gradually becoming mainstream. However, traditional water-based architectural coatings still have shortcomings in flame-retardant and fire-resistant properties. They easily produce large amounts of smoke during combustion, and due to component instability during storage, they are prone to thickening, precipitation, and crystallization, affecting their performance and application. Therefore, developing architectural coatings that combine good storage stability with low-smoke flame-retardant properties has become a research hotspot in this field.

[0003] Patent document CN116731565A discloses a decorative anti-mildew and antibacterial interior wall coating. It achieves antibacterial, formaldehyde-degrading, and heat-insulating effects by adding a multi-layered antibacterial agent with a graphene-like structure. However, this coating does not address the flame retardancy and storage stability issues of the magnesium-potassium ion system and relies on antibacterial agents with special structures, resulting in high costs. Patent CN117511380A discloses a graphene-modified waterborne polyurethane coating. It improves storage stability and film performance through modified graphene and titanium dioxide. However, this coating is mainly used for wood coatings, and its flame retardant and fire-resistant properties are not significantly improved. Furthermore, the preparation of graphene materials is complex and expensive. Patent CN116535927A discloses a building coating that uses a modified core-shell styrene-acrylic emulsion loaded with Mg-Al layered bimetallic hydroxide to achieve flame retardancy and damping sound insulation. However, this solution relies on a complex emulsion modification process and does not solve the problem of crystallization precipitation during storage of the high-concentration magnesium / potassium citrate system.

[0004] Therefore, there is a lack of architectural and decorative coatings in the current technology that are simple to process, cost-effective, and possess both excellent storage stability and low-smoke flame retardant properties. How to utilize magnesium and potassium ions to synergistically enhance the flame retardant effect without introducing complex modification processes, while simultaneously solving the technical challenge of easy crystallization and precipitation of high-concentration magnesium salts and citrate ions during storage, is a pressing technical problem to be solved in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention aims to provide a magnesium-potassium ion-containing architectural decorative coating and its preparation method.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A magnesium-potassium ion-containing architectural decorative coating comprises the following raw materials in parts by weight: 0.1-1 parts thickener, 23-50 parts water, 2-6 parts anhydrous magnesium citrate, 1-5 parts potassium citrate, 1-5 parts dispersant, 8-15 parts pigment, 0.5-1.5 parts coordination functional agent, 40-60 parts styrene-acrylic emulsion, 1-5 parts film-forming aid, 0.1-0.3 parts emulsifier, 1-5 parts leveling agent, and 2-6 parts defoamer.

[0007] The thickener is at least one of hydroxyethyl cellulose, polyacrylamide, and sodium carboxymethyl cellulose.

[0008] The dispersant is at least one of BYK-110, BYK-190, and BYK-184.

[0009] The pigment is at least one of titanium dioxide, iron oxide red, and zinc oxide.

[0010] The defoamer is at least one of silicone-based defoamers or mineral oil-based defoamers.

[0011] The film-forming aid is at least one of ethylene glycol, propylene glycol, ethylene glycol ethyl ether, and dodecyl alcohol ester.

[0012] The emulsifier is at least one of OP-10, AEO-9, sodium dodecylbenzenesulfonate, and sodium dodecyl sulfate.

[0013] The leveling agent is at least one of BYK-307, BYK-310, BYK-320, and BYK-354.

[0014] The coordination functional agent is at least one of polyaspartic acid, zirconium α-phosphate, gallic acid, polyglutamic acid, sodium hexametaphosphate, and titanium pyrophosphate.

[0015] The coordination functional aid is composed of polyaspartic acid and α-zirconium phosphate in a mass ratio of 4-6:2-4.

[0016] The preparation method of the magnesium-potassium ion-containing architectural decorative coating is as follows: First, add the thickener to water and stir at 100-500 rpm for 10-50 minutes at room temperature until completely dissolved to obtain a pre-solution. Heat the water to 35-55℃, add anhydrous magnesium citrate and potassium citrate, and stir until completely dissolved. Add the dispersant, pigment, coordination agent, and defoamer, and disperse at 800-1500 rpm for 10-30 minutes. Lower the material temperature to 20-35℃ and reduce the stirring speed to 400-800 rpm, add the styrene-acrylic emulsion, and stir at 100-500 rpm for 5-20 minutes. Quickly pour in the pre-emulsified film-forming agent and emulsifier, and stir for 1-10 minutes. Then add the leveling agent, pre-solution, and defoamer, and stir at 500-1000 rpm for 5-15 minutes. Let stand to defoam, and pass through an 80-150 mesh sieve to obtain a magnesium-potassium ion-containing architectural decorative coating.

[0017] Existing architectural decorative coatings have shortcomings in terms of flame retardant and fireproof performance. This invention addresses these shortcomings by adding anhydrous magnesium citrate and potassium citrate to the formula, utilizing Mg... 2+ At high temperatures, MgO is generated to enhance the strength of the carbon layer, and K... + A low-melting-point glassy melt barrier layer is formed, while citrate ions participate in the char formation reaction as a carbon source, thereby significantly improving the flame retardant and smoke-suppressing properties of the coating.

[0018] High concentration of Mg 2+ Citrate ions tend to slowly crystallize and precipitate during paint storage, leading to a sharp increase in viscosity and precipitation. Furthermore, when using magnesium potassium salts alone, the char layer after combustion remains relatively loose and the smoke density is high. To address these issues, this invention introduces a coordination functional additive: utilizing the polycarboxyl groups of polyaspartic acid or polyglutamic acid to react with Mg... 2+ The formation of soluble polymeric chelates inhibits crystallization and improves storage stability. Simultaneously, the introduction of α-zirconium phosphate or titanium pyrophosphate facilitates char formation via layered solid acid catalysis or a high-temperature reaction with MgO to generate a dense ceramic layer, further reducing smoke density. During combustion, citrate ions pyrolyze into a carbon skeleton, and Mg... 2+ Transformed into nano-MgO filling and reinforcing carbon layer, K + A low-melting-point glassy melt barrier layer is formed; the acidic sites of α-zirconium phosphate promote the low-temperature aromatization of carbon source, and titanium pyrophosphate reacts with MgO to generate magnesium titanium phosphate ceramic phase, which synergistically forms a dense ceramic-carbon composite protective layer with MgO, effectively isolating oxygen and heat transfer.

[0019] To further achieve a synergistic effect of storage stability and flame retardancy and smoke suppression, this invention preferably uses a combination of polyaspartic acid and α-zirconium phosphate, which are separated by Mg... 2+ Bridged structures construct flexible chelating and rigid layered organic-inorganic hybrid networks: polyaspartic acid provides a carbon source and chelates and stabilizes Mg. 2+The catalytic carbonization of α-zirconium phosphate forms a layered barrier, preventing crystallization and precipitation of the coating during storage, significantly reducing the viscosity change rate, and drastically decreasing the smoke density level during combustion.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects: 1) This invention utilizes Mg by adding anhydrous magnesium citrate and potassium citrate. 2+ High-temperature generation of MgO enhances the strength of the carbon layer, K + It forms a low-melting-point glassy melt barrier layer, which significantly improves the fire resistance of the coating and meets the high fire resistance requirements of building decoration materials.

[0021] 2) This invention introduces polycarboxylic acid or polyglutamic acid and other polycarboxyl coordination aids, which, together with Mg 2+ It forms a soluble polymer chelate, which effectively inhibits the crystallization of magnesium citrate, so that the viscosity change rate of the coating is ≤10% after 30 days of accelerated storage at 50℃, and the storage stability exceeds 6 months.

[0022] 3) In this invention, polyaspartic acid is preferably compounded with α-zirconium phosphate. During storage, the carboxyl groups of polyaspartic acid react with the Mg group. 2+ A soluble ionic bond network is formed, and the α-zirconium phosphate sheets are connected by Mg. 2+ The electrostatic adsorption effect uniformly disperses within it, forming a dynamic organic-inorganic hybrid network, effectively inhibiting the crystallization and precipitation of magnesium salts; during combustion, this network pyrolyzes, converting polyaspartic acid into a carbon skeleton, α-zirconium phosphate catalyzes carbonization and forms a layered barrier, Mg 2+ It is converted into MgO to fill the pores of the carbon layer, so that the coating can simultaneously obtain a heat-insulating carbon layer structure and excellent anti-settling properties, and its comprehensive performance is better than that of a single additive. Detailed Implementation

[0023] The sources or parameters of some substances are as follows: Hydroxyethyl cellulose: CAS 9004-62-0, Dow QP-15000H type, viscosity 1100-1500 cP (1% aqueous solution, 25℃).

[0024] Dispersant BYK-190: BYK Chemicals, 40% non-volatile matter, density 1.06 g / mL.

[0025] Titanium dioxide: Rutile type R-996, Lomon Billions, TiO2 content ≥93%.

[0026] Mineral oil-based defoamer: BASF Foamaster MO NXZ, density 0.89-0.95 g / mL.

[0027] Styrene-acrylic emulsion: Badifu RS-998A type, solid content 48±1%, Brookfield viscosity 4000-8000 cps (25℃, 3# rotor 12rpm), pH 6-8.

[0028] Dodecyl alcohol ester: Eastman Texanol, CAS 25265-77-4, purity ≥99%, density 0.95 g / mL.

[0029] OP-10: CAS 9002-93-1, HLB value 13-14.

[0030] BYK-354 leveling agent: BYK Chemicals, density 0.95 g / mL.

[0031] Polyaspartic acid: CAS 25608-40-6, water treatment grade, average molecular weight 1000-5000, white powder.

[0032] Zirconium α-phosphate: CAS 13772-29-7, white powder, purity ≥99%, D50≤1μm.

[0033] Gallic acid: CAS 149-91-7, white to grayish-white crystals, purity ≥99%, melting point 235-240℃.

[0034] Polyglutamic acid: CAS 25513-46-6, cosmetic grade, low molecular weight 10kDa, white powder.

[0035] Sodium hexametaphosphate: CAS 10124-56-8, white powder, 1% aqueous solution pH 5.5-6.5.

[0036] Titanium pyrophosphate: CAS 13470-09-2, white powder, purity ≥99%, D50=2.5±0.3μm.

[0037] In the embodiments and comparative examples of this invention, all raw materials are commercially available products. Example 1

[0038] A method for preparing a magnesium-potassium ion-containing architectural decorative coating is as follows, by weight parts: First, add 0.5 parts hydroxyethyl cellulose to 5 parts water and stir at 200 rpm for 30 minutes at room temperature until completely dissolved to obtain a pre-solution. Heat 30 parts water to 45°C, add 4 parts anhydrous magnesium citrate and 3 parts potassium citrate, and stir until completely dissolved. Add 3 parts dispersant BYK-190, 12 parts titanium dioxide, 0.8 parts coordination functional additives, and 2 parts mineral oil-based defoamer, and disperse at 1000 rpm for 20 minutes. Lower the material temperature to 30°C and reduce the speed to 700 rpm, add 50 parts styrene-acrylic emulsion, and stir at 200 rpm for 10 minutes. Quickly pour in 3 parts dodecyl alcohol ester and 0.2 parts OP-10 pre-emulsified, and stir for 5 minutes. Then add 3 parts BYK-354 leveling agent, the pre-solution, and 2 parts mineral oil-based defoamer, stir at 800 rpm for 10 minutes, let stand to defoam, and pass through a 100-mesh sieve to obtain a magnesium-potassium ion-containing architectural decorative coating.

[0039] The coordination functional aid is polyaspartic acid. Example 2

[0040] The preparation method of a magnesium-potassium ion-containing architectural decorative coating is basically the same as that in Example 1, except that the coordination functional agent is α-zirconium phosphate. Example 3

[0041] The preparation method of a magnesium-potassium ion-containing architectural decorative coating is basically the same as that in Example 1, except that the coordination functional agent is gallic acid. Example 4

[0042] The preparation method of a magnesium-potassium ion-containing architectural decorative coating is basically the same as that in Example 1, except that the coordination functional agent is polyglutamic acid. Example 5

[0043] The preparation method of a magnesium-potassium ion-containing architectural decorative coating is basically the same as that in Example 1, except that the coordination functional additive is sodium hexametaphosphate. Example 6

[0044] The preparation method of a magnesium-potassium ion-containing architectural decorative coating is basically the same as that in Example 1, except that the coordination functional additive is titanium pyrophosphate. Example 7

[0045] The preparation method of a magnesium-potassium ion-containing architectural decorative coating is basically the same as that in Example 1, except that the coordination functional additive is composed of polyaspartic acid and α-zirconium phosphate in a mass ratio of 5:3. Example 8

[0046] The preparation method of a magnesium-potassium ion-containing architectural decorative coating is basically the same as that in Example 1, except that the coordination functional additive is composed of sodium hexametaphosphate and gallic acid in a mass ratio of 5:3.

[0047] Comparative Example 1 The preparation method of a magnesium-potassium ion-containing architectural decorative coating is basically the same as that in Example 1, except that the anhydrous magnesium citrate and potassium citrate are not added.

[0048] Comparative Example 2 The preparation method of a magnesium-potassium ion-containing architectural decorative coating is basically the same as that in Example 1, except that the coordination functional additives are not added.

[0049] Test Example 1 Storage stability test: Referring to GB / T 6753.3-1986 "Test Method for Storage Stability of Coatings", approximately 500 mL of magnesium-potassium ion-containing architectural decorative coating samples prepared in each example and comparative example were placed into clean, dry, sealed containers and stored in a constant temperature oven at (50±2)℃ for 30 days. After the storage period, the samples were removed, cooled to room temperature, and then opened for inspection. The samples were mechanically stirred at 200 r / min until homogeneous, and the following phenomena were visually observed: skinning, gelation, stratification, precipitation and crystallization, and precipitate agglomeration. The precipitate was scraped from the bottom of the container with a spatula and observed whether the precipitate was loose and could be stirred. The rotational viscosity of the samples at (23±2)℃ was measured using a rotational viscometer (rotor No. 2, 12 r / min), and the viscosity change rate was calculated: viscosity change rate (%) = (viscosity after storage - viscosity before storage) / viscosity before storage × 100%. Samples that, after stirring, show no crystallization, no crusting, and exhibit loose, easily stirred precipitate with a viscosity change rate ≤15% are deemed to have satisfactory storage stability. Test results are shown in Table 1.

[0050] Table 1 Example 1 No crystals precipitated, the precipitate was loose and homogeneous after stirring. 8.1 Example 2 A small amount of sediment at the bottom, no crystallization, and homogeneous after stirring. 12.3 Example 3 Slight yellowing, no crystallization, loose precipitate 10.4 Example 4 No crystals were precipitated; the precipitate was loose and uniform. 7.8 Example 5 No crystallization, viscosity slightly increased, precipitate can be stirred. 13.7 Example 6 A small amount of sediment settled at the bottom, with no crystallization, and the mixture became homogeneous after stirring. 12.9 Example 7 No crystals were precipitated; the precipitate was loose and uniform in state. 9.6 Example 8 Slight flocculation, a small amount of crystallization, and a relatively hard precipitate. 18.6 Comparative Example 1 No crystallization, homogeneous without stratification, no precipitation. 5.3 Comparative Example 2 A large amount of crystals precipitate out, forming clumps that are difficult to disperse when stirred. 27.5 Test Example 2 Smoke Density Rating (SDR) Measurement: Referring to GB / T 8627-2007 "Test Method for Smoke Density of Building Materials During Combustion or Decomposition", magnesium-potassium ion-containing architectural decorative coating samples prepared in each embodiment and comparative example were poured into molds, naturally dried at room temperature for 48 hours, and then dried in a 60℃ oven for 24 hours until constant weight was achieved, forming sample blocks with dimensions of 25.4mm × 25.4mm × 6.0mm. Smoke density was measured using a building material smoke density tester. The sample blocks were placed horizontally above the burner in the test chamber, with propane as the fuel gas, the flame height adjusted to 25mm ± 2mm, the fuel gas flow rate at 0.1MPa, and the test time after ignition at 4 minutes. During the test, the light flux loss transmitted through the smoke chamber was measured. The light flux data was collected by computer, and the smoke density change curve over time was automatically calculated. The smoke density rating (SDR) was calculated according to the integral method specified in the standard. Three samples were tested for each group, and the arithmetic mean was taken, accurate to 0.01%. The relevant test data are summarized in Table 2.

[0051] Table 2 Example 1 28.7 Example 2 22.6 Example 3 31.3 Example 4 29.4 Example 5 35.1 Example 6 21.3 Example 7 19.9 Example 8 38.2 Comparative Example 1 42.8 Comparative Example 2 40.6 Comparative Example 1 did not contain anhydrous magnesium citrate or potassium citrate, and the system did not contain free Mg. 2+ and K + Therefore, the double layer on the surface of the styrene-acrylic emulsion particles is not compressed, resulting in strong electrostatic repulsion. There is no risk of electrolyte-induced aggregation or crystallization during storage, hence its viscosity change rate is significantly lower than all examples containing magnesium and potassium salts. Comparative Example 2, although containing magnesium and potassium salts, did not add any coordination functional agents, resulting in a high concentration of Mg... 2+ During storage, citrate ions readily crystallize out slowly, forming numerous crystals and inducing particle bridging and flocculation, leading to a sharp increase in viscosity. Simultaneously, due to the lack of synergistic additives, the char layer is loose during combustion, resulting in a high smoke density. In Examples 1-6, Example 4 exhibits a smaller viscosity change rate because the polyglutamic acid molecular chain contains densely packed γ-carboxyl groups, which interact with Mg... 2+ The formation of stable soluble polymeric chelates effectively inhibits magnesium citrate crystallization, and its long-chain structure provides steric hindrance, which is superior to polyaspartic acid and gallic acid. The smoke density level of Example 6 is even lower because titanium pyrophosphate reacts with MgO produced by the decomposition of magnesium citrate at high temperature to form a dense titanium magnesium phosphate ceramic layer. This ceramic layer firmly covers the surface of the carbon layer, significantly isolating heat and oxygen transfer, and the smoke suppression effect is better than that of α-zirconium phosphate, which only provides layered physical barrier, and Examples 1 and 4, which rely solely on their own carbonization.

[0052] Example 7 uses a blend of polyaspartic acid and α-zirconium phosphate. Although its storage viscosity change rate is slightly higher than that of polyaspartic acid alone, it is still far superior to Comparative Example 2 without coordination functional additives. Furthermore, its smoke density grade is significantly lower than that of Examples 1 and 2, where either ingredient is used alone. This is because polyaspartic acid chelates Mg through its carboxyl groups. 2+A stable ionic network is formed, while the layered structure of α-zirconium phosphate is facilitated by Mg. 2+ The bridging and crosslinking of polyaspartic acid chains form a flexible chelated and rigid layered organic-inorganic hybrid network after film formation. This network provides a char source for polyaspartic acid during combustion and also plays a role in catalyzing char formation and providing sheet-like barrier effects for α-zirconium phosphate, resulting in a synergistic smoke suppression effect. In contrast, Example 8, which used a combination of sodium hexametaphosphate and gallic acid, showed very poor results, with high viscosity change rate and smoke density levels. This may be because sodium hexametaphosphate has a poor effect on Mg... 2+ The complexation constant of gallic acid is much higher than that of gallic acid, and the two compete for Mg. 2+ This leads to the disruption of the gallic acid polyphenol network, preventing the formation of an effective metal-polyphenol coordination structure. Simultaneously, the strong chelation of sodium hexametaphosphate excessively consumes free magnesium. 2+ This weakens the char-forming ability of magnesium citrate during combustion, ultimately resulting in a dual deterioration in storage flocculation and flame retardant properties.

Claims

1. A magnesium-potassium ion-containing architectural decorative coating, characterized in that, Including the following parts by weight of raw materials: 0.1-1 parts thickener, 23-50 parts water, 2-6 parts anhydrous magnesium citrate, 1-5 parts potassium citrate, 1-5 parts dispersant, 8-15 parts pigment, 0.5-1.5 parts coordination functional agent, 40-60 parts styrene-acrylic emulsion, 1-5 parts film-forming aid, 0.1-0.3 parts emulsifier, 1-5 parts leveling agent, and 2-6 parts defoamer; The coordination functional agent is at least one of polyaspartic acid, zirconium α-phosphate, gallic acid, polyglutamic acid, sodium hexametaphosphate, and titanium pyrophosphate.

2. The magnesium-potassium ion-containing architectural decorative coating as described in claim 1, characterized in that, The thickener is at least one of hydroxyethyl cellulose, polyacrylamide, and sodium carboxymethyl cellulose.

3. The magnesium-potassium ion-containing architectural decorative coating as described in claim 1, characterized in that, The dispersant is at least one of BYK-110, BYK-190, and BYK-184.

4. The magnesium-potassium ion-containing architectural decorative coating as described in claim 1, characterized in that, The pigment is at least one of titanium dioxide, iron oxide red, and zinc oxide.

5. The magnesium-potassium ion-containing architectural decorative coating as described in claim 1, characterized in that, The defoamer is at least one of silicone-based defoamers or mineral oil-based defoamers.

6. The magnesium-potassium ion-containing architectural decorative coating as described in claim 1, characterized in that, The film-forming aid is at least one of ethylene glycol, propylene glycol, ethylene glycol ethyl ether, and dodecyl alcohol ester.

7. The magnesium-potassium ion-containing architectural decorative coating as described in claim 1, characterized in that, The emulsifier is at least one of OP-10, AEO-9, sodium dodecylbenzenesulfonate, and sodium dodecyl sulfate.

8. The magnesium-potassium ion-containing architectural decorative coating as described in claim 1, characterized in that, The leveling agent is at least one of BYK-307, BYK-310, BYK-320, and BYK-354.

9. The magnesium-potassium ion-containing architectural decorative coating as described in claim 1, characterized in that, The coordination functional aid is composed of polyaspartic acid and α-zirconium phosphate in a mass ratio of 4-6:2-4.

10. A method for preparing a magnesium-potassium ion-containing architectural decorative coating as described in any one of claims 1-9, characterized in that, The method is as follows: First, add the thickener to water and stir at 100-500 rpm for 10-50 minutes at room temperature until completely dissolved to obtain a pre-solution for later use. Heat the water to 35-55℃, add anhydrous magnesium citrate and potassium citrate, and stir until completely dissolved. Add the dispersant, pigment, coordination functional aid, and defoamer, and disperse at 800-1500 rpm for 10-30 minutes. Lower the material temperature to 20-35℃ and reduce the stirring speed to 400-800 rpm, add the styrene-acrylic emulsion, and stir at 100-500 rpm for 5-20 minutes. After pre-emulsifying the film-forming aid and emulsifier, quickly pour them in and stir for 1-10 minutes; then add the leveling agent, pre-solution and defoamer, stir at 500-1000 r / min for 5-15 minutes, let stand to defoam, and pass through an 80-150 mesh sieve to obtain the magnesium-potassium ion-containing architectural decorative coating.