Acrylic acid waterproof coating and preparation method thereof

Abstract

The invention relates to the technical field of waterproof materials, and particularly discloses an acrylic acid waterproof coating and a preparation method thereof. The acrylic acid waterproof coating provided by the invention is prepared from the following raw materials: a weather-resistant high-elastic emulsion, a modified filler, an auxiliary agent and water, the weather-resistant high-elasticity emulsion is prepared from the following raw materials: high-elasticity acrylic emulsion, vinyl-terminated hydroxyl-terminated fluorine-containing silicone oil, diisocyanate and dihydric alcohol; the modified filler is prepared from the following raw materials: barium sulfate, wollastonite, oleic acid modified titanium dioxide, an anionic dispersant and 2-ethylhexyl diphenyl phosphate; the auxiliary agent is prepared from cyclohexane-1, 2-dicarboxylic acid diisooctyl ester. Through the design of the weather-resistant high-elastic emulsion and the modified filler, and in cooperation with the specific plasticizer and other auxiliaries, the comprehensive properties such as adhesive force, water resistance, weather resistance and low temperature resistance of the acrylic waterproof coating are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of waterproof coatings, and in particular to an acrylic waterproof coating and a preparation method thereof. Background Art

[0002] Acrylic waterproof coatings are primarily made from acrylic copolymers or pure acrylic emulsions, along with supplementary materials. They offer excellent weather resistance, structural stability within temperatures ranging from -30°C to 80°C, and excellent ductility. They effectively prevent coating breakdown, water leaks, and seepage caused by wall subsidence or cracks. Acrylic waterproof coatings are also widely used in building waterproofing due to their ease of application, fast drying speed, and environmental friendliness.

[0003] However, existing acrylic waterproof coatings still have shortcomings such as low tensile strength and bonding strength, and poor water resistance. Although acrylic single-component waterproof coatings have a high elongation at break, they have low tensile strength. At the same time, their film-forming substance is an organic material acrylic emulsion, which has poor affinity for inorganic material cement, resulting in low bonding strength of the coating to the cement base. In addition, this type of coating has high viscosity and is prone to a large number of bubbles during production, which affects its strength. In the process of synthesizing acrylic ester emulsions, a large amount of hydrophilic monomers and emulsifiers are required. The hydrophilic groups will be exposed on the surface of the film during the film-forming process. At the same time, some small molecule emulsifiers will also migrate to the surface of the film over time. These will cause the film to stick, turn white, bubble, or even fall off, seriously affecting the performance of the product. Although the water resistance of the coating can be improved by introducing silicone and some self-crosslinking monomers, this can easily lead to a decrease in the adhesion between the coating and the substrate. Therefore, the art urgently needs a single-component waterproof coating that can be used outdoors, has weather resistance, is cheaper, more environmentally friendly, and easy to apply. Summary of the Invention

[0004] In response to the above problems, the present invention provides an acrylic waterproof coating and a preparation method thereof. By designing a weather-resistant high-elastic emulsion and modified fillers, and combining them with specific plasticizers and other additives, the comprehensive performance of the acrylic waterproof coating, such as adhesion, water resistance, weather resistance and low-temperature resistance, is improved.

[0005] In order to solve the above technical problems, the technical solution provided by the present invention is: In a first aspect, the present invention provides an acrylic waterproof coating comprising the following raw materials in parts by weight: 420 to 480 parts of a weather-resistant high-elastic emulsion, 425 to 510 parts of a modified filler, 7.5 to 15 parts of an additive, and 60 to 75 parts of water; The weather-resistant high-elastic emulsion comprises the following raw materials: high-elastic acrylic emulsion, vinyl-terminated hydroxyl-terminated fluorinated silicone oil, diisocyanate and diol; The modified filler comprises the following raw materials in parts by mass: 240 to 280 parts of barium sulfate, 140 to 180 parts of wollastonite, 25 to 35 parts of oleic acid-modified titanium dioxide, 3.5 to 4.5 parts of anionic dispersant, and 12 to 20 parts of 2-ethylhexyl diphenyl phosphate (DPOP); The auxiliary agent includes diisooctyl cyclohexane-1,2-dicarboxylate.

[0006] Compared to existing technologies, the acrylic waterproof coating provided by the present invention leverages the synergistic effects of each raw material by limiting their composition and content, effectively enhancing the overall performance of the acrylic waterproof coating. The highly elastic acrylic emulsion, the primary component of the weather-resistant high-elasticity emulsion, provides the coating with excellent elasticity due to its molecular chain flexibility, effectively adapting to deformation of the substrate caused by temperature fluctuations, structural settlement, and other factors, preventing cracking. Furthermore, the film-forming properties of the highly elastic acrylic emulsion create a continuous, dense waterproof barrier. Combined with its water resistance and low-temperature flexibility, this ensures long-term waterproof performance. The vinyl-terminated, hydroxyl-terminated fluorosilicone oil incorporates fluorine, creating high fluorocarbon (CF) bond energy, significantly improving the coating's weather resistance, resisting ultraviolet (UV)-induced photooxidative degradation, and slowing chalking and yellowing. The silicone oil's low surface energy imparts hydrophobicity and anti-fouling properties to the coating, allowing water to bead off the coating surface, reducing stain adhesion and microbial growth. The chemical inertness of the fluorosilicone oil makes it resistant to corrosion by chemical media such as acids, alkalis, and salts, making it suitable for use in polluted industrial environments. Furthermore, the hydroxyl groups in vinyl-terminated, hydroxyl-terminated fluorosilicone oils can participate in the polymerization reaction of diisocyanates and diols to form a polyurethane crosslinked network. The rigid structure of the urethane bonds enhances the tensile and tear strength of the coating while maintaining elasticity, and imparting a certain degree of aging resistance and adhesion. Under certain conditions, the vinyl groups in vinyl-terminated, hydroxyl-terminated fluorosilicone oils can also undergo crosslinking polymerization with highly elastic acrylic emulsions, further increasing the system's degree of branching, thereby improving the overall performance of the waterproof coating and extending its service life.

[0007] Among the modified fillers, barium sulfate, a high-density filler, fills the coating's pores through a microaggregate effect, enhancing tensile strength. Wollastonite, with its needle-like structure, forms a physically crosslinked network through bridging, further improving elongation at break and tear strength. The combination of low-thermal-expansion barium sulfate and high-temperature-resistant wollastonite optimizes the coating's thermal stability and enhances wear resistance. Oleic acid, through its hydrophobic segments, adsorbs on the surface of titanium dioxide, improving its dispersion in the organic phase. The carboxyl groups of oleic acid also form hydrogen bonds with the hydroxyl groups of the acrylate polymer, strengthening interfacial adhesion and preventing yellowing caused by titanium dioxide migration. Furthermore, oleic acid inhibits the photocatalytic activity of titanium dioxide, reducing UV-induced free radical degradation and thus improving the coating's aging resistance. Anionic dispersants, through electrostatic repulsion and steric hindrance, enable inorganic fillers like barium sulfate and wollastonite to form a nanoscale dispersion in the coating, preventing sedimentation and stratification. DPOP contains a long ethylhexyl chain and two phenyl groups, which are both polar and hydrophobic. It has good compatibility with acrylic resins. The long chain can provide steric hindrance and reduce filler agglomeration. The phosphate group has a strong adsorption effect on the surface hydroxyl groups of titanium dioxide and silica fume, and its effect on improving dispersibility is better than that of ordinary aliphatic phosphates.

[0008] Preferably, in the weather-resistant high-elastic emulsion, the mass ratio of the high-elasticity acrylic emulsion, the vinyl-terminated and hydroxyl-terminated fluorinated silicone oil, the diisocyanate and the diol is (15-20):(1-2):(2-3):1.

[0009] The present invention further exerts the synergistic effect of various raw materials by controlling the amount of each raw material of the weather-resistant high-elastic emulsion, and organically combines the weather resistance of acrylic acid, the mechanical properties of polyurethane, and the surface characteristics of fluorine-containing silicone oil through molecular design.

[0010] Preferably, the ionicity of the high elasticity acrylic emulsion is anionic, the ion diameter is 100nm~300nm, and the pH is 7.9~8.1.

[0011] Preferably, the high elasticity acrylic emulsion has a solid content of 51% to 53%, a Brookfield viscosity of 550 mPa·s to 5000 mPa·s, and a minimum film-forming temperature of less than 0°C.

[0012] More preferably, the high elasticity acrylic emulsion is FS-6699A produced by Budford Company.

[0013] The preferred high-elasticity acrylic emulsion of this invention is a highly environmentally friendly, APEO (alkylphenol polyoxyethylene ether)-free, formaldehyde-free, and derivative-free high-performance elastic emulsion derived from acrylic acid copolymerization. Utilizing emulsion self-crosslinking technology and UV-curable oligomerization technology, it forms a flexible, pollution-resistant coating with excellent weathering and aging resistance. When applied to a one-component waterproof coating, it imparts excellent tensile properties and tear strength, along with superior low-temperature performance and water resistance.

[0014] Preferably, the structural formula of the vinyl-terminated hydroxyl-terminated fluorinated silicone oil is as follows: H2=CH-Si(CH3)2-[O-Si(CH3)(CH2-CF3)] a -O-Si(CH3)2-OH Wherein, a represents an integer from 50 to 120.

[0015] The preferred vinyl-terminated hydroxyl-terminated fluorinated silicone oil of the present invention has a suitable fluorine content and an appropriate molecular weight, which can further balance the weather resistance and mechanical properties of the coating.

[0016] Preferably, the diisocyanate includes at least two of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI) or dicyclohexylmethane diisocyanate (HMDI).

[0017] Further preferably, the mass ratio of any two of the diisocyanates is (0.6-1.5):1.

[0018] The present invention selects two or more diisocyanates, and through the complementarity of structure and performance, takes into account the advantages of a single diisocyanate and makes up for the shortcomings, so as to achieve more comprehensive performance of the polyurethane prepolymer (and the final coating), more controllable process, and more reasonable cost. It is particularly suitable for coating scenarios with high requirements for comprehensive performance (such as outdoor weather resistance and balanced mechanical strength) or cost sensitivity.

[0019] Preferably, the diol comprises ethylene glycol.

[0020] Preferably, the preparation method of the weather-resistant high-elastic emulsion comprises the following steps: S1. Under an inert atmosphere, add diisocyanate, vinyl-terminated hydroxyl-terminated fluorinated silicone oil and diol into a reaction kettle and react at 60°C to 70°C to obtain a polyurethane prepolymer; S2. Adding a high-elasticity acrylic emulsion and a catalyst to the polyurethane prepolymer, reacting at 75° C. to 85° C. to obtain the weather-resistant high-elasticity emulsion.

[0021] The present invention first generates a polyurethane prepolymer through a polymerization reaction between an isocyanate group and a hydroxyl group, and then uses a vinyl group and a high-elasticity acrylic emulsion to carry out a certain polymerization reaction to increase the branching degree of the acrylic polymer, thereby further improving the comprehensive performance of the coating.

[0022] Further preferably, in S1, the inert atmosphere includes a nitrogen atmosphere.

[0023] Further preferably, in S1, the reaction time is 1 h to 2 h.

[0024] Further preferably, in S2, the catalyst is an organotin catalyst. More preferably, the catalyst includes stannous octoate.

[0025] Further preferably, in S2, the mass of the catalyst is 0.1% to 0.3% of the reaction system.

[0026] Further preferably, in S2, the reaction time is 2h~3h.

[0027] Preferably, the weather-resistant high-elastic emulsion has a solid content of 65% to 70%, a Brookfield viscosity of 600 mPa·s to 3000 mPa·s, and a density of 1.4 g / cm 3 ~1.5g / cm 3 .

[0028] Preferably, the preparation method of the oleic acid-modified titanium dioxide comprises the following steps: The molten oleic acid is sprayed onto the titanium dioxide, and the mixture is stirred at a high speed for reaction to obtain the oleic acid-modified titanium dioxide.

[0029] The present invention chemically adsorbs or reacts oleic acid molecules with hydroxyl groups on the surface of titanium dioxide, utilizes mechanical shear force to promote uniform coating of oleic acid on the surface of titanium dioxide, improves its surface hydrophobicity, and thus enhances the compatibility of the filler with organic resins such as acrylates.

[0030] Further preferably, the titanium dioxide needs to be pretreated as follows before use: Add titanium dioxide into the acid solution, stir and immerse, centrifuge, wash and dry.

[0031] The present invention can effectively remove impurities (such as free ions and physically adsorbed water) on the surface of titanium dioxide through acid impregnation, thereby avoiding subsequent adverse effects on the modification effect.

[0032] More preferably, the mass volume ratio of the titanium dioxide to the acid solution is 1 g: (6-10) mL.

[0033] More preferably, the pH of the acid solution is 2-3.

[0034] More preferably, the stirring and immersing is carried out at room temperature for 30 to 60 minutes.

[0035] More preferably, the titanium dioxide comprises rutile titanium dioxide.

[0036] Further preferably, the mass ratio of oleic acid to titanium dioxide is (2-5):100.

[0037] The present invention has found through a large number of experiments that if the amount of oleic acid used is too little, the surface of titanium dioxide is not fully coated and the hydrophobicity is not sufficiently improved; if the amount of oleic acid used is too much, free oleic acid will remain, which may cause the coating system to become sticky or the performance to deteriorate.

[0038] For example, oleic acid is liquefied by heating in a water bath to 40° C. to 50° C. to obtain molten oleic acid.

[0039] More preferably, the high-speed stirring reaction temperature is 60° C. to 80° C., the stirring rate is 1000 rpm to 2000 rpm, and the time is 45 min to 60 min.

[0040] Preferably, the anionic dispersant includes a polycarboxylate sodium salt dispersant. Further preferably, the anionic dispersant includes San Nopco SN-5040 from Japan.

[0041] The preferred dispersant of the present invention uses water as a carrier, does not contain formaldehyde, has high effective dispersion efficiency for inorganic fillers, has low foaming and excellent wettability, can improve the fluidity and gloss of the coating, and stabilize the viscosity of the slurry.

[0042] Preferably, the preparation method of the modified filler comprises the following steps: The raw materials are weighed according to the designed ratio, mixed and ball-milled for 60 minutes to 100 minutes to obtain the modified filler.

[0043] Preferably, the auxiliary agent comprises the following raw materials in parts by mass: 2.5 to 3.5 parts of diisooctyl cyclohexane-1,2-dicarboxylate, 2.5 to 3.5 parts of defoaming agent, 1.2 to 1.8 parts of multifunctional amine auxiliary agent and 1.2 to 1.8 parts of preservative.

[0044] More preferably, the defoaming agent comprises a metal soap defoaming agent. More preferably, the defoaming agent comprises defoaming agent NXZ.

[0045] The preferred defoamer of the present invention has excellent defoaming and anti-foaming effects on water-based coatings, and also has excellent compatibility and high safety.

[0046] More preferably, the multifunctional amine adjuvant includes AMP-95 from The Dow Chemical Company, USA.

[0047] The preferred multifunctional amine auxiliary agent of the present invention is an organic base, which is relatively soft and belongs to an environmentally friendly regulator. It has excellent compatibility with specific weather-resistant high-elastic emulsions, has excellent alkaline strength (higher pH value), stability, efficient pigment dispersibility and scrub resistance, is not easy to turn yellow, can effectively prevent flocculation, and improve the wettability of the system, thereby helping to improve the water resistance of the coating.

[0048] More preferably, the preservative includes an isothiazolinone preservative. More preferably, the preservative includes kasone.

[0049] Kathon is a mixture of 2-methyl-4-isothiazolin-3-one (MI), 2-methyl-5-chloro-4-isothiazolin-3-one (CMI) and inorganic salt stabilizer (usually CM1:MI=3:1). It is a highly effective broad-spectrum fungicide with strong biological activity that can inhibit the growth of microorganisms.

[0050] Preferably, the viscosity of the acrylic waterproof coating is 100KU~110KU.

[0051] More preferably, an alkali-swellable associative thickener is used to adjust the viscosity of the acrylic waterproof coating.

[0052] For example, the alkali-swellable associative thickener can be diluted with water at a ratio of 1:1 (v / v) and then added to the system to adjust the viscosity.

[0053] The preferred thickener of the present invention can temporarily thin the paint under the stirring of the brush, making the painting process more labor-saving; when the brush leaves the wall, it can restore the paint's consistency, preventing the paint from flowing down the wall, making the consistency moderate, thereby ensuring uniform coating thickness and reducing the trouble of rework.

[0054] In a second aspect, the present invention provides a method for preparing the acrylic waterproof coating, comprising the following steps: Weigh all raw materials according to the designed ratio, mix them evenly, and obtain acrylic waterproof coating.

[0055] Preferably, the preparation method of the acrylic waterproof coating specifically comprises the following steps: Weigh the raw materials according to the designed ratio, add the weather-resistant high-elastic emulsion, dispersant, defoamer and multifunctional amine additive into water and mix evenly, then add the modified filler and diisooctyl cyclohexane-1,2-dicarboxylate, use an alkali-swellable associative thickener to adjust the viscosity of the system, then add the preservative, mix evenly, and obtain the acrylic waterproof coating.

[0056] The present invention has the following beneficial effects: The present invention limits the components and ratios of the weather-resistant high-elastic emulsion, and through molecular design and multi-component collaboration, organically combines the weather resistance of acrylic, the mechanical properties of polyurethane, and the surface characteristics of fluorinated silicone oil to form an integrated solution with high elasticity, strong weather resistance, and super hydrophobicity. It is widely used in scenarios with strict durability requirements such as metal roofs, bridges, and underground projects.

[0057] The present invention achieves high performance and green acrylic waterproof coating by limiting the components and proportions of modified fillers, through inorganic reinforcement, interface modification, and functional synergy, extending the service life of the coating and reducing the maintenance cost throughout the entire life cycle. There is a synergistic effect between the components. The carboxyl group of oleic acid modified titanium dioxide reacts with the hydroxyl group of acrylate polymer to form a chemical anchor point, and the phosphate group of DPOP reacts with the Ba on the surface of barium sulfate. 2+ The formation of coordination bonds further enhances the interfacial network. The UV shielding properties of titanium dioxide and the reflective properties of barium sulfate synergize with the photostabilizing groups (benzene ring structure) of DPOP to further enhance the coating's weather resistance. The dispersant's optimized rheological properties enable the coating to cure rapidly, shortening the construction period. The flexibility of DPOP and the micro-penetration ability of wollastonite enable the coating to repair cracks smaller than 0.2 mm on concrete surfaces, adapting to complex substrates and achieving self-healing properties. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0059] In the examples of the present invention, deionized water was used; the high-elasticity acrylic emulsion FS-6699A was purchased from Bardford, with an ionic diameter of 150 nm to 250 nm, a pH of 8 ± 1, a solids content of 52% ± 1%, a Brookfield viscosity of 600 mPa·s to 3000 mPa·s, and a minimum film-forming temperature of less than 0°C; vinyl-terminated and hydroxyl-terminated fluorosilicone oil was purchased from Anhui Aiyota Silicone Oil Co., Ltd.; the wollastonite particle size passed a 1250-mesh sieve; the anionic dispersant SN-5040 was purchased from San Nopco, Japan; the defoamer was NXZ; the multifunctional amine additive was purchased from The Dow Chemical Company, USA, AMP-95; and the preservative was Kasson. All other materials, unless otherwise specified, were commercially available.

[0060] Example 1 This embodiment provides an acrylic waterproof coating, comprising the following raw materials in parts by mass: 450 parts of a weather-resistant high-elastic emulsion, 470 parts of a modified filler, 3 parts of diisooctyl cyclohexane-1,2-dicarboxylate, 3 parts of a defoamer, 1.5 parts of a multifunctional amine additive, 1.5 parts of a preservative, an alkali-swellable associative thickener (the amount used is based on viscosity), and 65.5 parts of water.

[0061] The weather-resistant, high-elastic emulsion consists of the following raw materials: a high-elasticity acrylic emulsion, vinyl-terminated and hydroxyl-terminated fluorosilicone oil, diisocyanate, and ethylene glycol in a mass ratio of 18:1.5:2.5:1. The weather-resistant, high-elastic emulsion has a solids content of 68.5%, a Brookfield viscosity of 1500 mPa·s, and a density of 1.45 g / cm 3 The structural formula of vinyl-terminated and hydroxy-terminated fluorinated silicone oil is as follows: H2=CH-Si(CH3)2-[O-Si(CH3)(CH2-CF3)] 80 -O-Si(CH3)2-OH. The diisocyanate is composed of TDI and HMDI in a mass ratio of 0.8:1.

[0062] The modified filler includes the following raw materials in parts by mass: 260 parts of precipitated barium sulfate, 160 parts of wollastonite, 30 parts of oleic acid-modified titanium dioxide, 4 parts of anionic dispersant and 16 parts of DPOP.

[0063] The preparation method of the above acrylic waterproof coating comprises the following steps: S100, Preparation of Weather-Resistant High-Elasticity Emulsion and Modified Filler: S101. Under a nitrogen atmosphere, add diisocyanate, vinyl-terminated and hydroxyl-terminated fluorinated silicone oil and ethylene glycol into a reaction kettle, react at 65° C., and keep the temperature for 1.5 hours to obtain a polyurethane prepolymer.

[0064] S102. Add high-elastic acrylic emulsion and stannous octoate to the polyurethane prepolymer, with the mass of stannous octoate being 0.2% of the reaction system. React at 80° C. and keep warm for 2.5 hours to obtain a weather-resistant high-elastic emulsion.

[0065] S110. Add rutile titanium dioxide into water with a mass volume ratio of rutile titanium dioxide to water of 1 g:8 mL. Adjust the pH of the system to 2.5 with 5% dilute hydrochloric acid. Stir and soak at room temperature for 50 minutes, centrifuge, wash to neutrality, and dry to obtain pretreated titanium dioxide.

[0066] S120. Add the pretreated titanium dioxide into a high-speed mixer, slowly spray molten oleic acid, the mass ratio of oleic acid to pretreated titanium dioxide being 4:100, and stir at 70° C. and 1500 rpm for 55 minutes. Dry at 60° C. to constant weight to obtain oleic acid-modified titanium dioxide.

[0067] The oleic acid modified titanium dioxide was tested by infrared spectroscopy (FTIR) and it was found that the oleic acid modified titanium dioxide had a -1 、2850 cm -1 (CH stretching vibration of oleic acid) and 1700 cm -1A new peak appears near the characteristic peak after the reaction of carboxyl and titanium hydroxyl groups, proving that oleic acid is successfully coated on the surface of titanium dioxide.

[0068] S130. Weigh all raw materials according to the designed ratio, mix and ball-mill for 80 minutes to obtain a modified filler.

[0069] It should be noted that this embodiment does not limit the order of S101 - S102 and S110 - S130 .

[0070] S200. Weigh all raw materials according to the designed ratio, add weather-resistant high-elastic emulsion, dispersant, defoaming agent and multifunctional amine additive into water, mix evenly, then add modified filler and diisooctyl cyclohexane-1,2-dicarboxylate, use alkali-swellable associative thickener to adjust the system viscosity to 106KU, then add preservative, mix evenly to obtain acrylic waterproof coating.

[0071] Example 2 This embodiment provides an acrylic waterproof coating, comprising the following raw materials in parts by mass: 440 parts of a weather-resistant high-elastic emulsion, 471.5 parts of a modified filler, 2.5 parts of diisooctyl cyclohexane-1,2-dicarboxylate, 3.5 parts of a defoamer, 1.8 parts of a multifunctional amine additive, 1.2 parts of a preservative, an alkali-swellable associative thickener (the amount used is based on viscosity), and 70 parts of water.

[0072] The weather-resistant, high-elastic emulsion consists of the following raw materials: a high-elasticity acrylic emulsion, vinyl-terminated and hydroxyl-terminated fluorosilicone oil, diisocyanate, and ethylene glycol in a mass ratio of 16:1.5:2.5:1. The weather-resistant, high-elastic emulsion has a solids content of 67.0%, a Brookfield viscosity of 1000 mPa·s, and a density of 1.42 g / cm 3 The structural formula of vinyl-terminated and hydroxy-terminated fluorinated silicone oil is as follows: H2=CH-Si(CH3)2-[O-Si(CH3)(CH2-CF3)] 90 -O-Si(CH3)2-OH. The diisocyanate is composed of MDI and IPDI in a mass ratio of 1.2:1.

[0073] The modified filler includes the following raw materials in parts by mass: 250 parts of precipitated barium sulfate, 170 parts of wollastonite, 35 parts of oleic acid-modified titanium dioxide, 4.5 parts of anionic dispersant and 12 parts of DPOP.

[0074] The preparation method of the above acrylic waterproof coating comprises the following steps: S100, Preparation of Weather-Resistant High-Elasticity Emulsion and Modified Filler: S101. Under a nitrogen atmosphere, add diisocyanate, vinyl-terminated and hydroxyl-terminated fluorinated silicone oil and ethylene glycol into a reaction kettle, react at 70° C., and keep the temperature for 1.2 hours to obtain a polyurethane prepolymer.

[0075] S102. Add high-elastic acrylic emulsion and stannous octoate to the polyurethane prepolymer, with the mass of stannous octoate being 0.3% of the reaction system. React at 85° C. and keep warm for 2 hours to obtain a weather-resistant high-elastic emulsion.

[0076] S110. Add rutile titanium dioxide into water with a mass volume ratio of rutile titanium dioxide to water of 1 g:10 mL. Adjust the pH of the system to 3 with 5% dilute hydrochloric acid. Stir and immerse for 60 minutes at room temperature. Centrifuge, wash until neutral, and dry to obtain pretreated titanium dioxide.

[0077] S120. Add the pretreated titanium dioxide into a high-speed mixer, slowly spray molten oleic acid, the mass ratio of oleic acid to pretreated titanium dioxide being 3:100, and react at 60° C. and 1000 rpm for 60 min. Dry at 60° C. to constant weight to obtain oleic acid-modified titanium dioxide.

[0078] The oleic acid modified titanium dioxide was tested by infrared spectroscopy (FTIR) and it was found that the oleic acid modified titanium dioxide had a -1 、2850 cm -1 (CH stretching vibration of oleic acid) and 1700 cm -1 A new peak appears near the characteristic peak after the reaction of carboxyl and titanium hydroxyl groups, proving that oleic acid is successfully coated on the surface of titanium dioxide.

[0079] S130. Weigh all raw materials according to the designed ratio, mix and ball-mill for 100 minutes to obtain a modified filler.

[0080] It should be noted that this embodiment does not limit the order of S101 - S102 and S110 - S130 .

[0081] S200. Weigh all raw materials according to the designed ratio, add weather-resistant high-elastic emulsion, dispersant, defoaming agent and multifunctional amine additive into water, mix evenly, then add modified filler and diisooctyl cyclohexane-1,2-dicarboxylate, use alkali-swellable associative thickener to adjust the system viscosity to 103KU, then add preservative, mix evenly to obtain acrylic waterproof coating.

[0082] Example 3 This embodiment provides an acrylic waterproof coating, comprising the following raw materials in parts by mass: 420 parts of a weather-resistant high-elastic emulsion, 425 parts of a modified filler, 3.5 parts of diisooctyl cyclohexane-1,2-dicarboxylate, 2.5 parts of a defoamer, 1.8 parts of a multifunctional amine additive, 1.2 parts of a preservative, an alkali-swellable associative thickener (the amount used is based on viscosity), and 60 parts of water.

[0083] The weather-resistant high-elastic emulsion consists of the following raw materials: a high-elastic acrylic emulsion, a vinyl-terminated hydroxyl-terminated fluorosilicone oil, a diisocyanate, and ethylene glycol in a mass ratio of 20:2:3:1. The weather-resistant high-elastic emulsion has a solids content of 65.0%, a Brookfield viscosity of 800 mPa·s, and a density of 1.4 g / cm 3 The structural formula of vinyl-terminated and hydroxy-terminated fluorinated silicone oil is as follows: H2=CH-Si(CH3)2-[O-Si(CH3)(CH2-CF3)] 55 -O-Si(CH3)2-OH. The diisocyanate is composed of HDI, IPDI and HMDI in a mass ratio of 0.8:1:1.2.

[0084] The modified filler includes the following raw materials in parts by mass: 240 parts of precipitated barium sulfate, 140 parts of wollastonite, 25 parts of oleic acid-modified titanium dioxide, 3.5 parts of anionic dispersant and 16.5 parts of DPOP.

[0085] The preparation method of the above acrylic waterproof coating comprises the following steps: S100, Preparation of Weather-Resistant High-Elasticity Emulsion and Modified Filler: S101. Under a nitrogen atmosphere, add diisocyanate, vinyl-terminated and hydroxyl-terminated fluorinated silicone oil and ethylene glycol into a reaction kettle, react at 60° C., and keep the temperature for 2 hours to obtain a polyurethane prepolymer.

[0086] S102. Add high-elastic acrylic emulsion and stannous octoate to the polyurethane prepolymer, with the mass of stannous octoate being 0.1% of the reaction system, and react at 75° C. for 3 hours to obtain a weather-resistant high-elastic emulsion.

[0087] S110. Add rutile titanium dioxide into water with a mass volume ratio of rutile titanium dioxide to water of 1 g:6 mL. Adjust the pH of the system to 2 with 5% dilute hydrochloric acid. Stir and soak at room temperature for 35 minutes, centrifuge, wash to neutrality, and dry to obtain pretreated titanium dioxide.

[0088] S120. Add the pretreated titanium dioxide into a high-speed mixer, slowly spray molten oleic acid, the mass ratio of oleic acid to pretreated titanium dioxide being 5:100, stir at 80° C. and 2000 rpm for 45 minutes, and dry at 60° C. to constant weight to obtain oleic acid-modified titanium dioxide.

[0089] S130. Weigh all raw materials according to the designed ratio, mix and ball-mill for 70 minutes to obtain a modified filler.

[0090] It should be noted that this embodiment does not limit the order of S101 - S102 and S110 - S130 .

[0091] S200. Weigh all raw materials according to the designed ratio, add weather-resistant high-elastic emulsion, dispersant, defoaming agent and multifunctional amine additive into water, mix evenly, then add modified filler and diisooctyl cyclohexane-1,2-dicarboxylate, use alkali-swellable associative thickener to adjust the system viscosity to 110KU, then add preservative, mix evenly to obtain acrylic waterproof coating.

[0092] Example 4 This embodiment provides an acrylic waterproof coating, comprising the following raw materials in parts by mass: 480 parts of a weather-resistant high-elastic emulsion, 510 parts of a modified filler, 3 parts of diisooctyl cyclohexane-1,2-dicarboxylate, 3 parts of a defoaming agent, 1.4 parts of a multifunctional amine additive, 1.6 parts of a preservative, an alkali-swellable associative thickener (the amount used is based on viscosity), and 75 parts of water.

[0093] The weather-resistant, high-elastic emulsion consists of the following raw materials: a high-elastic acrylic emulsion, vinyl-terminated and hydroxyl-terminated fluorosilicone oil, diisocyanate, and ethylene glycol in a mass ratio of 15:1:2:1. The weather-resistant, high-elastic emulsion has a solids content of 70.0%, a Brookfield viscosity of 2200 mPa·s, and a density of 1.5 g / cm 3 The structural formula of vinyl-terminated and hydroxy-terminated fluorinated silicone oil is as follows: H2=CH-Si(CH3)2-[O-Si(CH3)(CH2-CF3)] 110 -O-Si(CH3)2-OH. The diisocyanate is composed of TDI, MDI, and IPDI in a mass ratio of 1:1:1.

[0094] The modified filler includes the following raw materials in parts by mass: 280 parts of precipitated barium sulfate, 180 parts of wollastonite, 26.5 parts of oleic acid-modified titanium dioxide, 3.5 parts of anionic dispersant and 20 parts of DPOP.

[0095] The preparation method of the above acrylic waterproof coating comprises the following steps: S100, Preparation of Weather-Resistant High-Elasticity Emulsion and Modified Filler: S101. Under a nitrogen atmosphere, add diisocyanate, vinyl-terminated and hydroxyl-terminated fluorinated silicone oil and ethylene glycol into a reaction kettle, react at 65° C., and keep the temperature for 1.5 hours to obtain a polyurethane prepolymer.

[0096] S102. Add high-elastic acrylic emulsion and stannous octoate to the polyurethane prepolymer, with the mass of stannous octoate being 0.2% of the reaction system. React at 80° C. and keep warm for 2.5 hours to obtain a weather-resistant high-elastic emulsion.

[0097] S110. Add rutile titanium dioxide into water with a mass volume ratio of rutile titanium dioxide to water of 1 g:7 mL. Adjust the pH of the system to 2.5 with 5% dilute hydrochloric acid. Stir and soak at room temperature for 45 minutes, centrifuge, wash to neutrality, and dry to obtain pretreated titanium dioxide.

[0098] S120. Add the pretreated titanium dioxide into a high-speed mixer, slowly spray molten oleic acid, the mass ratio of oleic acid to pretreated titanium dioxide being 2:100, and stir at 70°C and 1500 rpm for 50 minutes. Dry at 60°C to constant weight to obtain oleic acid-modified titanium dioxide.

[0099] S130. Weigh all raw materials according to the designed ratio, mix and ball-mill for 90 minutes to obtain a modified filler.

[0100] It should be noted that this embodiment does not limit the order of S101 - S102 and S110 - S130 .

[0101] S200. Weigh all raw materials according to the designed ratio, add weather-resistant high-elastic emulsion, dispersant, defoaming agent and multifunctional amine additive into water, mix evenly, then add modified filler and diisooctyl cyclohexane-1,2-dicarboxylate, use alkali-swellable associative thickener to adjust the system viscosity to 100KU, then add preservative, mix evenly to obtain acrylic waterproof coating.

[0102] Example 5 This example provides an acrylic waterproof coating. Its raw materials and proportions are similar to those of Example 1, with the only difference being that the high-elasticity acrylic emulsion (FS-6699A from Bardford) in the weather-resistant high-elasticity emulsion is replaced with Wanhua 8515A of equivalent quality. The coating has a solids content of 52% ± 1%, a Brookfield viscosity of 400 mPa·s, and a minimum film-forming temperature of 0°C. The remaining components and their proportions are the same as those of Example 1 and are not further described.

[0103] The preparation method of the above acrylic waterproof coating is the same as that in Example 1 and will not be repeated here.

[0104] Comparative Example 1 This comparative example provides an acrylic waterproof coating. Its raw materials and proportions are similar to those of Example 1, except that the vinyl-terminated and hydroxyl-terminated fluorinated silicone oil in the weather-resistant high-elasticity emulsion is omitted. The mass ratio of the high-elasticity acrylic emulsion, diisocyanate, and ethylene glycol is 18:2.5:1. The remaining components and their amounts are the same as those of Example 1 and are not further described.

[0105] The preparation method of the acrylic waterproof coating is similar to that of Example 1, except that the addition of vinyl-terminated and hydroxyl-terminated fluorinated silicone oil is omitted in S101. The remaining steps and conditions are the same as those of Example 1 and are not further described.

[0106] Comparative Example 2 This comparative example provides an acrylic waterproof coating. Its raw materials and proportions are similar to those of Example 1, differing only in that the weather-resistant, high-elastic emulsion is a high-elastic acrylic emulsion, and the vinyl-terminated, hydroxyl-terminated fluorinated silicone oil, diisocyanate, and ethylene glycol are omitted. The remaining components and their amounts are the same as those of Example 1 and are not further described.

[0107] The preparation method of the acrylic waterproof coating is similar to that of Example 1, except that steps S101 to S102 are omitted in S100. The remaining steps and conditions are the same as those of Example 1 and are not described in detail.

[0108] Comparative Example 3 This comparative example provides an acrylic waterproof coating. Its raw materials and proportions are similar to those of Example 1, differing only in that the oleic acid-modified titanium dioxide in the modified filler is replaced with titanium dioxide of equal mass; that is, the titanium dioxide is not oleic acid-modified. The remaining components and their amounts are the same as those of Example 1 and are not further described.

[0109] The preparation method of the acrylic waterproof coating is similar to that of Example 1, except that step S120 is omitted. The remaining steps and conditions are the same as those of Example 1 and are not described in detail.

[0110] Comparative Example 4 This comparative example provides an acrylic waterproof coating. The raw materials and proportions are similar to those in Example 1, except that the oleic acid-modified titanium dioxide in the modified filler is replaced with an equivalent mass of wollastonite. Thus, the addition of oleic acid-modified titanium dioxide is omitted, and the amount of wollastonite added is 190 parts. The remaining components and amounts are the same as in Example 1 and are not further described.

[0111] The preparation method of the acrylic waterproof coating is similar to that of Example 1, except that steps S110 to S120 are omitted. The remaining steps and conditions are the same as those of Example 1 and are not described again.

[0112] Comparative Example 5 This comparative example provides an acrylic waterproof coating. The raw materials and proportions are similar to those in Example 1, except that the oleic acid-modified titanium dioxide and wollastonite in the modified filler are replaced with an equal mass of precipitated barium sulfate. That is, the addition of wollastonite and oleic acid-modified titanium dioxide is omitted, and the amount of precipitated barium sulfate added is 450 parts. The remaining components and amounts are the same as in Example 1 and are not further described.

[0113] The preparation method of the acrylic waterproof coating is similar to that of Example 1, except that steps S110 to S120 are omitted. The remaining steps and conditions are the same as those of Example 1 and are not described again.

[0114] Comparative Example 6 This comparative example provides an acrylic waterproof coating. Its raw materials and proportions are similar to those of Example 1, except that DPOP in the modified filler is replaced with an equivalent mass of epoxysilane KH-560. The remaining components and their contents are the same as those of Example 1 and are not further described.

[0115] The preparation method of the above acrylic waterproof coating is the same as that in Example 1 and will not be repeated here.

[0116] Comparative Example 7 This comparative example provides an acrylic waterproof coating. Its raw materials and proportions are similar to those of Example 2, differing only in that diisooctyl cyclohexane-1,2-dicarboxylate is replaced with an equal mass of dibutyl phthalate (DBP) in the additive. The remaining components and their contents are the same as those of Example 2 and are not further described.

[0117] The preparation method of the acrylic waterproof coating is similar to that of Example 2, except that in S200, diisooctyl cyclohexane-1,2-dicarboxylate is replaced with DBP. The remaining steps and conditions are the same as those of Example 2 and are not further described.

[0118] Verification test The acrylic waterproof coatings provided in Examples 1-5 and Comparative Examples 1-7 were used as test samples for relevant performance testing. Three specimens were prepared for each sample, and the average of the three specimens was calculated. The results are shown in Tables 1 and 2. The test samples of Examples 1-5 were all uniform and viscous, without gel, delamination, or agglomeration.

[0119] Table 1 Performance test results of acrylic waterproof coatings of Examples 1 to 5

[0120] Table 2 Performance test results of acrylic waterproof coatings of Comparative Examples 1 to 7

[0121] As can be seen from the table, the acrylic waterproof coatings provided in Examples 1 to 4 of the present invention have excellent comprehensive properties, with a tensile strength of 1.5 MPa to 1.8 MPa, a tear strength of 18.3 N / mm to 19.7 N / mm, no cracks when bent at a low temperature of -25°C, a bonding strength of 1.34 MPa to 1.48 MPa under standard conditions, and a bonding strength of 0.95 MPa to 0.99 MPa under a moist base surface, and excellent water resistance, heat resistance, and chemical resistance.

[0122] After changing the composition or dosage of the weather-resistant high-elastic emulsion in Example 5 and Comparative Examples 1-2, the overall performance of the acrylic waterproof coating was slightly reduced. After changing the composition or dosage of the modified filler in Comparative Examples 3-6 and the plasticizer component in the additive in Comparative Example 7, the overall performance of the acrylic waterproof coating showed varying degrees of decline.

[0123] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An acrylic waterproof coating, characterized in that: The composition comprises the following raw materials in parts by weight: 420 to 480 parts of weather-resistant high-elastic emulsion, 425 to 510 parts of modified filler, 7.5 to 15 parts of additive, and 60 to 75 parts of water; The weather-resistant high-elastic emulsion comprises the following raw materials: high-elastic acrylic emulsion, vinyl-terminated hydroxyl-terminated fluorinated silicone oil, diisocyanate and diol; The modified filler comprises the following raw materials in parts by mass: 240 to 280 parts of barium sulfate, 140 to 180 parts of wollastonite, 25 to 35 parts of oleic acid-modified titanium dioxide, 3.5 to 4.5 parts of anionic dispersant, and 12 to 20 parts of 2-ethylhexyl diphenyl phosphate; The auxiliary agent includes diisooctyl cyclohexane-1,2-dicarboxylate.

2. The acrylic waterproof coating according to claim 1, wherein In the weather-resistant high-elastic emulsion, the mass ratio of high-elastic acrylic emulsion, vinyl-terminated hydroxyl-terminated fluorinated silicone oil, diisocyanate and diol is (15-20):(1-2):(2-3):1; The weather-resistant high-elastic emulsion has a solid content of 65% to 70%, a Brookfield viscosity of 600 mPa·s to 3000 mPa·s, and a density of 1.4 g / cm 3 ~1.5g / cm 3 .

3. The acrylic waterproof coating according to claim 1, wherein The high-elasticity acrylic emulsion has anionic ionicity, an ion diameter of 100nm~300nm, pH=7.9~8.1, a solid content of 51%~53%, a Brookfield viscosity of 550mPa·s~5000mPa·s, and a minimum film-forming temperature of less than 0°C.

4. The acrylic waterproof coating according to claim 1, wherein The structural formula of the vinyl-terminated hydroxyl-terminated fluorinated silicone oil is as follows: H2=CH-Si(CH3)2-[O-Si(CH3)(CH2-CF3)] a -O-Si(CH3)2-OH Wherein, a represents an integer from 50 to 120.

5. The acrylic waterproof coating according to claim 1, wherein The diisocyanate comprises at least two of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate or dicyclohexylmethane diisocyanate; the mass ratio of any two of the diisocyanates is (0.6-1.5):1; The diol includes ethylene glycol; The anionic dispersant includes a polycarboxylate sodium salt dispersant.

6. The acrylic waterproof coating according to any one of claims 1 to 5, characterized in that: The preparation method of the weather-resistant high-elastic emulsion comprises the following steps: S1. Under an inert atmosphere, add diisocyanate, vinyl-terminated hydroxyl-terminated fluorinated silicone oil and diol into a reaction kettle and react at 60°C to 70°C to obtain a polyurethane prepolymer; S2. Adding a high-elasticity acrylic emulsion and a catalyst to the polyurethane prepolymer, reacting at 75° C. to 85° C. to obtain the weather-resistant high-elasticity emulsion.

7. The acrylic waterproof coating according to claim 1, wherein The preparation method of the oleic acid-modified titanium dioxide comprises the following steps: The molten oleic acid is sprayed onto the titanium dioxide, and the mixture is stirred at a high speed for reaction to obtain the oleic acid-modified titanium dioxide.

8. The acrylic waterproof coating according to claim 7, wherein: The titanium dioxide comprises rutile titanium dioxide; the mass ratio of oleic acid to titanium dioxide is (2-5):100; The high-speed stirring reaction temperature is 60° C. to 80° C., the stirring rate is 1000 rpm to 2000 rpm, and the time is 45 min to 60 min.

9. The acrylic waterproof coating according to claim 1, wherein The auxiliary agent comprises the following raw materials in parts by mass: 2.5 to 3.5 parts of diisooctyl cyclohexane-1,2-dicarboxylate, 2.5 to 3.5 parts of defoaming agent, 1.2 to 1.8 parts of multifunctional amine auxiliary agent and 1.2 to 1.8 parts of preservative.

10. The method for preparing the acrylic waterproof coating according to any one of claims 1 to 9, characterized in that: The following steps are involved: Weigh all raw materials according to the designed ratio, mix them evenly, and obtain acrylic waterproof coating.

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