Formula and process of waterproof heat-preservation water-based paint

Abstract

The invention discloses a formula of a waterproof heat-preservation water-based coating. The formula comprises the following components in parts by weight: 45-50 parts of organic silicon modified acrylic emulsion; 12 to 15 parts of a waterborne polyurethane dispersion; 15 to 25 parts of deionized water; 15 to 18 parts of mica powder; 3-5 parts of nano silicon dioxide; 2-3 parts of a polyester plasticizer; 1-2 parts of a coalescing agent; 0.3 to 0.5 part of an organic silicon defoaming agent; 0.2 to 0.5 part of an organic tin heat stabilizer; 0.1 to 0.2 part of a preservative; 3-5 parts of ceramic microbeads; 0.5-1 part of a wetting dispersant; compared with the traditional coating, the waterproof and heat-insulating properties are obviously improved.

Description

Technical Field

[0001] The present invention belongs to the field of coatings. Background Art

[0002] Traditional solvent-based coatings are gradually being replaced by waterborne coatings due to problems such as high VOC emissions and insufficient elasticity; however, conventional waterborne waterproof coatings still have obvious shortcomings in airtightness, heat resistance, and thermal insulation performance. Traditional waterborne acrylic coatings rely on physical film formation, and the long-term use temperature is generally lower than 80°C. Moreover, high filler systems are prone to cause a decrease in flexibility and poor thermal insulation performance; while polyurethane coatings have excellent elasticity, they have problems such as poor resistance to humid heat aging and high costs. In addition, complex temperature and humidity changes in building and industrial scenarios pose higher requirements for the breathability and thermal insulation of coatings. Conventional fillers (such as calcium carbonate) are difficult to balance the contradiction between denseness and elasticity, restricting the application of coatings in key scenarios such as roofs, pipelines, and solar energy equipment. Summary of the Invention

[0003] Object of the Invention: In order to overcome the deficiencies in the prior art, the present invention provides a formula and process for a waterproof and heat-insulating waterborne coating, which significantly improves the waterproof and heat-insulating performance compared with traditional coatings.

[0004] Technical Solution: To achieve the above object, a formula for a waterproof and heat-insulating waterborne coating of the present invention is as follows:

[0005] The proportion by weight is as follows:

[0006]

[0007] Further, on the basis of the above formula, the following components are added in proportion by weight:

[0008]

[0009]

[0010] Further, the mica powder is 800 mesh and flaky; the ceramic microspheres have a particle diameter of 20 μm and are hollow.

[0011] Further, the organosilicon-modified acrylic emulsion is a polymer composite emulsion formed by emulsion copolymerization of acrylate monomers and organosilicon monomers.

[0012] Further, the polyester plasticizer is a linear polyester formed by polycondensation of polyols and dibasic acids.

[0013] Further, the chemical composition of the film-forming aid: 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (C12H24O3);

[0014] The silicone defoamer is a polydimethylsiloxane (PDMS) emulsion or a modified silicone oil;

[0015] The wetting and dispersing agent is sodium polyacrylate or alkylphenol polyoxyethylene ether.

[0016] Furthermore, the organotin heat stabilizer is dimethyltin carboxylate or monobutyltin oxide.

[0017] Furthermore, the preservative is 1,2-benzisothiazolin-3-one (BIT).

[0018] Furthermore, the preparation process of the waterproof and heat-insulating waterborne coating formulation:

[0019] Step 1: Mix deionized water + wetting and dispersing agent + 50% of the defoamer in the ratio and stir at 200 - 300 rpm for more than 5 minutes; then continue to add mica powder, ceramic microspheres, and nano-silica in the ratio and disperse at 1200 - 1600 rpm for more than 30 minutes. Finally, pass through a sand mill until the fineness is ≤ 30 μm;

[0020] During the process of "Step 1", the ceramic microspheres need to be dispersed at ≤ 50°C to avoid emulsion gelation caused by high temperature. The temperature is ensured to be ≤ 50°C throughout the process through the cold circulation (refrigeration device) on the stirring tank container to prevent emulsion demulsification during premixing;

[0021] Step 2: Cool down to 30°C through the cold circulation (refrigeration device) on the stirring tank container, add the silicone-modified acrylic emulsion and polyurethane dispersion, and stir at 500 - 700 rpm for more than 10 minutes; then slowly add the film-forming aid and polyester plasticizer and continue to stir for 15 minutes;

[0022] Step 3: Add the organotin heat stabilizer, the remaining defoamer, and hydroxyethyl cellulose or hydroxypropyl methylcellulose pre-swollen with the remaining deionized water in the ratio, and stir at 500 - 700 rpm for more than 10 minutes to make the viscosity reach 95 - 105 KU; finally, add disodium edetate and sodium dihydrogen phosphate in the ratio in sequence and stir at 500 - 700 rpm for 10 minutes;

[0023] Step 4: Cool down to below 25°C through the cold circulation (refrigeration device) on the stirring tank container, and then add sodium bicarbonate in the ratio; stir at 500 - 700 rpm for 20 minutes;

[0024] Step 5: Pass through a 250-mesh filter screen and fill into a sealed container. Store at a temperature of 5 - 30°C, store in the dark, and strictly prohibit the container from being directly irradiated by sunlight.

[0025] The construction process of the waterproof and heat-insulating waterborne coating formulation:

[0026] S1. Under the condition that the ambient temperature is lower than 35°C, the prepared waterproof and heat-insulating waterborne coating is evenly applied to the surface of the target object that needs heat insulation and waterproofing, and the coating thickness is 2 mm to 4 mm.

[0027] S2. After the waterproof and heat-insulating coating surface dries in more than 60 minutes, a non-contact mask is applied to the surface-dried coating with a sunshade to avoid premature decomposition of sodium bicarbonate caused by direct sunlight heating, and air drying is supplemented at the same time.

[0028] S3. After 5 to 7 days, when the internal cross-linking of the waterproof and heat-insulating coating is completed and the elastic sealing performance is stable, a radiation heater is used to irradiate and heat the cured waterproof and heat-insulating coating until each local area of the waterproof and heat-insulating coating is successively heated to 120°C and maintained for 30 minutes.

[0029] Beneficial effects: The present invention improves the waterproof and heat-insulating performance compared with traditional coatings; especially in the second embodiment, the discrete and uniformly distributed small pressurized bubbles form an occupancy extrusion inside the waterproof and heat-insulating coating, so that the waterproof and heat-insulating coating undergoes extrusion elastic deformation under the occupancy extrusion of the discrete and uniformly distributed small pressurized bubbles inside. The part that has undergone elastic deformation has an elastic restoring force, so that the non-bubble part inside the waterproof and heat-insulating coating becomes denser under the occupancy extrusion of the bubbles. At the same time, the increased air pressure inside the pressurized bubbles is maintained (it should be noted that this waterproof and heat-insulating coating is essentially different from the traditional foamed coating. The bubbles in the foamed structure are generated before the coating cures, while the bubbles in this solution are generated after the elastic coating cures, and no continuous pressurization effect will be formed inside the bubbles, and thus no occupancy elastic extrusion force will be formed to make the non-bubble part inside the waterproof and heat-insulating coating denser). At the same time, the waterproof and heat-insulating coating thickens by about 1 mm under the action of the discrete bubbles inside, further improving the heat insulation, waterproof, crack resistance and tensile resistance performance; at the same time, the discrete and uniformly distributed small pressurized bubbles inside the waterproof and heat-insulating coating inhibit internal heat conduction, further improving the heat insulation ability of the waterproof and heat-insulating coating. Description of the Drawings

[0030] Figure 1 It is a process flow chart. Detailed Embodiments

[0031] The present invention will be further described in detail below with reference to the drawings.

[0032] First Embodiment:

[0033] A formula of a waterproof and heat-insulating waterborne coating is as follows according to parts by weight:

[0034]

[0035] The mica powder is 800 mesh and flaky. As a barrier filler, the mica powder has its flakes arranged in parallel, extending the gas penetration path and significantly enhancing the airtightness. The ceramic microspheres have a particle diameter of 20 μm and are hollow, reducing the thermal conductivity of the coating, minimizing thermal stress cracking, and assisting in heat insulation.

[0036] The silicone-modified acrylic emulsion is a polymer composite emulsion formed by emulsion copolymerization of acrylate monomers (butyl acrylate) and silicone monomers (silane coupling agents). Typical trade names: Dow Chemical: DOWSIL 7727 / Wacker Chemical: SILRES BS 692 / BASF. The silicone chain segments endow the coating with high-temperature resistance (the Si-O bond has a high bond energy and can withstand heat up to 120 - 150 °C), while the acrylic chain segments maintain elasticity (elongation at break > 300%). The silicone components migrate to the coating surface to form a hydrophobic layer, enhancing the waterproof property. Compared with ordinary acrylics, the heat resistance is increased to 120 °C, with anti-yellowing and elasticity retention. The aqueous polyurethane dispersion serves as a synergistic binder, maintaining low-temperature elasticity and synergistically enhancing the heat stability with the silicone acrylic.

[0037] The polyester plasticizer is a linear polyester formed by polycondensation of polyols (hexanediol) and dibasic acids (adipic acid), with a molecular weight of 2000 - 6000. Trade name: BASF: Plastomoll TP 759. The long-chain polyester molecules interpenetrate the resin network, providing flexibility through physical entanglement rather than chemical bonding and are not prone to migration at high temperatures (compared with the small molecule plasticizer DOP). It has good compatibility with the polyurethane dispersion and still maintains the plasticizing effect at low temperatures (-20 °C).

[0038] The chemical composition of the film-forming aid is 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (C12H24O3), which belongs to low-volatility alcohol ester solvents. Its mechanism of action is to lower the minimum film-forming temperature (MFFT) of the emulsion, promoting the fusion of acrylic / polyurethane latex particles into a continuous film during drying. It volatilizes slowly at high temperatures, preventing the coating from cracking due to rapid water loss.

[0039] The chemical composition of the silicone defoamer is polydimethylsiloxane (PDMS) emulsion or modified silicone oil (such as hydroxy silicone oil, polyether-modified silicone oil). Typical trade names: Evonik: TEGO Foamex 810 / Air Products and Chemicals: Surfynol MD - 20 / Shin-Etsu Chemical: KF - 96A. Its mechanism of action is that the silicone with low surface tension destroys the foam liquid film, quickly eliminating the bubbles during stirring and construction.

[0040] Chemical composition of the wetting and dispersing agent: Anionic type: Sodium polyacrylate (such as Dispex N40); Non-ionic type: Alkylphenol polyoxyethylene ether (such as TEGO Dispers 750); Mechanism of action: Adsorb on the surface of fillers (mica, ceramic microspheres), prevent particle agglomeration through electrostatic repulsion or steric hindrance; Improve the stability of the formulation and avoid sedimentation during storage.

[0041] Chemical composition of the organotin heat stabilizer: Methyltin type: Dimethyltin carboxylate (such as Advastab TM-181); Butyltin type: Monobutyltin oxide (C4H9SnO); The mechanism of action is to capture free radicals generated by the resin at high temperatures and delay the thermal degradation of acrylic / polyurethane chains.

[0042] The preservative is 1,2-benzisothiazolin-3-one (BIT) or its derivatives (such as BIT-20, containing 20% active ingredient); Trade name: Solvay: ACTICIDE BW 20; The mechanism of action is a broad-spectrum fungicide, inhibiting the growth of bacteria and molds during the storage of coatings, extending the shelf life; The addition amount needs to be strictly controlled, and excessive addition may affect the stability of the emulsion.

[0043] The specific ratio of the first embodiment is as follows:

[0044]

[0045]

[0046] Component interaction:

[0047] Silicone acrylic + polyurethane dispersion: Silicone provides a heat-resistant skeleton, and polyurethane gives low-temperature elasticity. The two crosslink through hydrogen bonds to form an interpenetrating network, balancing thermal stability and flexibility; Mica powder + ceramic microspheres: Mica flakes block gas, and ceramic microspheres reduce the thermal conductivity. The two form a double-barrier structure, improving airtightness and heat insulation simultaneously. Polyester plasticizer + organotin heat stabilizer: Polyester plasticizer reduces high-temperature migration, and organotin delays the breakage of resin chains, synergistically maintaining elasticity at high temperatures; This optimized formulation significantly improves airtightness and short-term heat resistance (resistant to 150°C) through base material modification, filler compounding, and additive upgrading, while maintaining elasticity (elongation rate > 300%); The production process needs to strictly control the dispersion fineness and temperature, and is applicable to scenarios such as roof waterproofing and insulation, high-temperature workshops, outdoor industrial equipment, and solar energy equipment.

[0048] Performance verification of the first embodiment

[0049]

[0050] Traditional commercially available acrylic thermal insulation coatings

[0051]

[0052]

[0053] In order to further improve the heat preservation, waterproof and airtight properties of the coating, the above formula is further optimized as follows:

[0054] Second Embodiment:

[0055] On the basis of the formula of the first embodiment, the following components are added according to the weight part ratio:

[0056]

[0057] Disodium edetate (EDTA-2Na) chelates calcium (Ca 2+ ), magnesium (Mg 2+ ) and other metal ions that may exist in any stage of the production process to prevent the decomposition of sodium bicarbonate; Sodium dihydrogen phosphate (NaH2PO4) maintains the pH value of the solution through a multi-stage dissociation equilibrium. Hydroxyethyl cellulose or hydroxypropyl methylcellulose not only regulates the viscosity to prevent sagging during construction, but also forms a viscous protective layer to slow down the ion diffusion in the solution and inhibit the decomposition. The principle of its optimized formula is described in detail in the process.

[0058] The preparation process and principle of the waterproof and heat-insulating waterborne coating formula of the second embodiment are as Figure 1 shown:

[0059] Step 1: Mix deionized water + wetting dispersant + 50% of the defoamer in the ratio and stir at 200 - 300 rpm for more than 5 minutes; then continue to add mica powder, ceramic microspheres, and nano-silica in the ratio and disperse at 1200 - 1600 rpm for more than 30 minutes, and finally pass through a sand mill until the fineness ≤ 30 μm;

[0060] During the process of "Step 1", the ceramic microspheres need to be dispersed at ≤ 50°C to avoid emulsion gelation caused by high temperature. The temperature ≤ 50°C is ensured throughout the process through the cold cycle (refrigeration device) on the stirring tank container to prevent demulsification during the pre-mixing of the emulsion;

[0061] Step 2: Cool down to 30°C through the cold cycle (refrigeration device) on the stirring tank container, add the silicone-modified acrylic emulsion and polyurethane dispersion, and stir at 500 - 700 rpm for more than 10 minutes; then slowly add the film-forming aid and polyester plasticizer and continue to stir for 15 minutes;

[0062] Step 3: Add organotin heat stabilizer, the remaining defoamer, and hydroxyethyl cellulose or hydroxypropyl methylcellulose pre-swollen with the remaining deionized water in proportion, stir at 500 - 700 rpm for more than 10 minutes until the viscosity reaches 95 - 105 KU; finally, add disodium edetate and sodium dihydrogen phosphate in proportion and stir at 500 - 700 rpm for 10 minutes. Disodium edetate (EDTA-2Na) chelates metal ions such as calcium (Ca 2+ ), magnesium (Mg 2+ ) to prevent the decomposition of sodium bicarbonate in "Step 4"; sodium dihydrogen phosphate (NaH2PO4) maintains the pH value of the solution through multi-stage dissociation equilibrium for the decomposition of sodium bicarbonate in "Step 4". In this case, hydroxyethyl cellulose or hydroxypropyl methylcellulose not only regulates the viscosity and prevents sagging during construction but also forms a viscous protective layer to slow down the ion diffusion in the solution and inhibit decomposition;

[0063] Step 4: To inhibit the decomposition of sodium bicarbonate in this step, cool it to below 25°C through the cold cycle (refrigeration device) on the stirring tank container, and then add sodium bicarbonate and the remaining components in proportion; stir at 500 - 700 rpm for 20 minutes;

[0064] Step 5: Filter through a 250-mesh sieve and fill it into a sealed container. Store it at a temperature of 5 - 30°C in the dark, and strictly prohibit the container from being directly irradiated by sunlight. At the same time, set an exhaust nozzle with a normally closed duckbill one-way valve on one side of the upper end of the container to avoid premature carbon dioxide pressure buildup and bursting of the container due to excessive internal temperature caused by long-term exposure to high temperature and sunlight.

[0065] Construction process of the waterproof and heat-insulating waterborne coating formula of the second embodiment:

[0066] S1: Construct under the condition that the ambient temperature is lower than 35°C. Uniformly apply the prepared waterproof and heat-insulating waterborne coating on the surface of the target object that needs heat insulation and waterproofing, with a coating thickness of 2 mm to 4 mm;

[0067] S2: After more than 60 minutes, the surface of the waterproof and heat-insulating coating is dry to the touch. Then, use a shading object to perform non-contact masking on the dry-to-touch coating to avoid premature decomposition of sodium bicarbonate caused by sunlight direct irradiation and temperature rise. At the same time, assist with air drying to accelerate drying and curing while avoiding temperature rise;

[0068] S3. After 5 to 7 days, when the internal cross-linking of the waterproof and heat-insulating coating is completed and the elastic sealing performance is stable, a radiation heater with strong penetration, such as in the infrared band with a wavelength of 15 - 1000 μm, is used to irradiate and heat the cured waterproof and heat-insulating coating. If the coating area is large, a multi-source matrix arrangement is adopted, combined with an arc-shaped reflector to correct the irradiation field to make the temperature uniformity error ≤ ±5%; until each local area of the waterproof and heat-insulating coating is successively heated to 120 °C and maintained for 30 minutes. At this time, the free radicals generated by the organotin heat stabilizers dimethyltin carboxylate and monobutyltin oxide in the waterproof and heat-insulating coating at high temperature delay the thermal degradation of the acrylic / polyurethane chain, thereby maintaining its stability and elasticity in the short term. Therefore, the waterproof and heat-insulating coating will only undergo reversible slight softening under the action of heating and still maintain its elasticity; at the same time, the sodium bicarbonate uniformly distributed inside the waterproof and heat-insulating coating gradually decomposes into sodium carbonate and releases carbon dioxide (CO2) gas. Due to the non-breathable characteristic of the waterproof and heat-insulating coating itself, the generated carbon dioxide (CO2) gas cannot escape from the waterproof and heat-insulating coating, thus generating small bubbles in a discrete and uniform pressurized state inside the elastic waterproof and heat-insulating coating. The bubble diameter is 100 μm - 300 μm. The discrete and uniform small pressurized bubbles form an occupancy extrusion inside the waterproof and heat-insulating coating, so that the waterproof and heat-insulating coating undergoes extrusion elastic deformation under the occupancy extrusion of the discrete and uniform small pressurized bubbles inside. The part that has undergone elastic deformation has an elastic restoring force, which makes the non-bubble part inside the waterproof and heat-insulating coating become denser under the occupancy extrusion of the bubbles. At the same time, the increased air pressure inside the pressurized bubbles is maintained (it should be noted that this waterproof and heat-insulating coating is essentially different from the traditional foamed coating. The bubbles in the foamed structure are generated before the coating cures, while the bubbles in this solution are generated after the elastic coating cures, and there will be no continuous pressurization effect inside the bubbles, and thus no occupancy elastic extrusion force will be formed to make the non-bubble part inside the waterproof and heat-insulating coating become denser under the occupancy extrusion of the bubbles). At the same time, the waterproof and heat-insulating coating thickens by about 1 mm under the action of the internal discrete bubbles, further improving the heat insulation, waterproof, crack resistance and tensile resistance performance; at the same time, the discrete and uniform small pressurized bubbles inside the waterproof and heat-insulating coating inhibit the internal heat conduction, further improving the heat insulation ability of the waterproof and heat-insulating coating.

[0069] According to the requirements of the construction process, verify the performance of the second embodiment

[0070]

[0071] The verification results show that the heat insulation, waterproof and airtightness of the second embodiment are significantly enhanced.

[0072] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A waterproof and heat-insulating waterborne coating formulation, characterized in that: The proportioning by weight parts is as follows:

2. The waterproof and heat-insulating waterborne coating formulation according to claim 1, characterized in that: On the basis of the formulation described in claim 1, the following components are added by weight part proportioning:

3. The water-proof and heat-insulating water-based coating formulation according to claim 1, characterized in that: The mica powder is 800 mesh and flaky; the ceramic microspheres have a particle diameter of 20 μm and are hollow.

4. A waterproof and heat-insulating waterborne coating formulation according to claim 1, characterized in that: The organosilicon-modified acrylic emulsion is a polymer composite emulsion formed by emulsion copolymerization of acrylate monomers and organosilicon monomers.

5. The formulation of a waterproof and heat-insulating waterborne coating according to claim 1, characterized in that: The polyester plasticizer is a linear polyester formed by polycondensation of polyols and dibasic acids.

6. A waterproof and heat-insulating waterborne coating formulation according to claim 1, characterized in that: The chemical composition of the film-forming aid: 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (C12H24O3); The organosilicon defoamer is polydimethylsiloxane (PDMS) emulsion or modified silicone oil; The wetting and dispersing agent is sodium polyacrylate or alkylphenol polyoxyethylene ether.

7. The formulation of a waterproof and heat-insulating waterborne coating according to claim 2, characterized in that: The organotin heat stabilizer is dimethyltin carboxylate or monobutyltin oxide.

8. A waterproof and heat-insulating water-based paint formulation according to claim 1, characterized in that: The preservative is 1,2-benzisothiazolin-3-one (BIT).

9. The preparation process of the waterproof and heat-insulating waterborne coating formulation according to claim 2, characterized in that: Step 1, mix deionized water + wetting and dispersing agent + 50% of the defoamer in the proportion at 200 - 300 rpm and stir for more than 5 minutes; then continue to add mica powder, ceramic microspheres, and nano-silica in the proportion and disperse at 1200 - 1600 rpm for more than 30 minutes, and finally pass through a sand mill until the fineness is ≤ 30 μm; During the process of "Step 1", the ceramic microspheres need to be dispersed at ≤ 50 °C to avoid emulsion gelation caused by high temperature. The temperature is ensured to be ≤ 50 °C throughout the process through the cold cycle (refrigeration device) on the stirring tank container to prevent emulsion demulsification during pre-mixing; Step 2, cool down to 30 °C through the cold cycle (refrigeration device) on the stirring tank container, add the organosilicon-modified acrylic emulsion and polyurethane dispersion, and stir at 500 - 700 rpm for more than 10 minutes; then slowly add the film-forming aid and polyester plasticizer and continue to stir for 15 minutes; Step 3, add the organotin heat stabilizer, the remaining defoamer, and hydroxyethyl cellulose or hydroxypropyl methylcellulose pre-swollen with the remaining deionized water in the proportion, stir at 500 - 700 rpm for more than 10 minutes to make the viscosity reach 95 - 105 KU; finally, add disodium edetate and sodium dihydrogen phosphate in the proportion in sequence and stir at 500 - 700 rpm for 10 minutes; Step 4, cool down to below 25 °C through the cold cycle (refrigeration device) on the stirring tank container, and then add sodium bicarbonate in the proportion; stir at 500 - 700 rpm for 20 minutes; Step 5, pass through a 250-mesh filter and fill it into a sealed container, store at a temperature of 5 - 30 °C, store in the dark, and it is strictly prohibited for the container to be directly irradiated by sunlight.

10. The construction process of the waterproof and heat-insulating waterborne coating formulation according to claim 2, characterized in that: S1, construct under the condition that the ambient temperature is lower than 35 °C, evenly brush the prepared waterproof and heat-insulating waterborne coating on the surface of the target object that needs heat insulation and waterproofing, and the brushing thickness is 2 mm to 4 mm; S2. After more than 60 minutes, the surface of the waterproof and heat-insulating coating becomes dry to the touch. Then, a non-contact mask is applied to the dry coating using a sunshade to prevent premature decomposition of sodium bicarbonate caused by temperature rise due to direct sunlight. At the same time, air drying is supplemented. S3. After 5 to 7 days, when the internal cross-linking of the waterproof and heat-insulating coating is completed and the elastic sealing performance is stable, a radiation heater is used to irradiate and heat the cured waterproof and heat-insulating coating until each local area of the waterproof and heat-insulating coating is successively heated to 120 °C and maintained for 30 minutes.

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