Modified high-reflection heat-insulation surface layer coating and preparation method thereof

Abstract

The invention relates to a modified high-reflection heat-insulation surface layer coating and a preparation method of the modified high-reflection heat-insulation surface layer coating. The coating is prepared from the following raw material components: 20 to 30 parts of acrylic resin, 20 to 30 parts of hyperbranched modified acrylic resin, 15 to 20 parts of titanium dioxide, 15 to 20 parts of electroless refrigeration powder, 5 to 20 parts of infrared reflection pigment, 5 to 10 parts of xylene, 5 to 10 parts of butyl acetate, 5 to 10 parts of ethyl acetate, 0.5 to 1 part of dispersing agent, 0.5 to 1 part of organic rheological agent and 0.1 to 0.5 part of fumed silica. The reflective heat-insulating and refrigerating surface coating has the advantages of high sunlight reflectivity, high hemispherical reflectivity, high near-infrared reflectivity and the like, and also has high weather resistance. The preparation method of the reflective heat-insulation refrigeration surface layer coating is simple in process and suitable for industrial production; the paint is suitable for the container body equipment facility coating process and flow, and the field construction efficiency is high.

Description

Technical Field

[0001] This invention relates to a topcoat and its preparation method, specifically to a modified high-reflectivity heat-insulating topcoat for container body coating and its preparation method. Background Technology

[0002] Applying heat-insulating coatings to container surfaces can significantly reduce the impact of temperature fluctuations on cargo quality, extend the storage time of temperature-sensitive goods such as fresh food and pharmaceuticals, and reduce the risk of spoilage during transportation. Furthermore, it can reduce the load on air conditioning systems, thereby effectively reducing fuel consumption and improving energy efficiency. Container surface coatings typically include primer, intermediate coat, and topcoat. The main function of the topcoat is to reflect the infrared portion of sunlight, reducing heat transfer to the intermediate and primer layers. This is primarily achieved by adding pigments and fillers with high infrared reflectivity. Additionally, the topcoat also possesses good aging resistance.

[0003] Traditional heat-insulating topcoats suffer from poor heat insulation performance, are prone to cracking due to their thick coating, and have poor aesthetic appearance. Therefore, there is an urgent need for a topcoat that combines heat insulation and mechanical properties, and can be well-matched with heat-insulating primer and intermediate coat systems to provide long-lasting and reliable heat insulation protection for containers. Summary of the Invention

[0004] The first technical problem to be solved by the present invention is to provide a modified high-reflectivity heat-insulating surface coating.

[0005] The second technical problem to be solved by the present invention is to provide a method for preparing the high-reflectivity heat-insulating surface coating.

[0006] The technical solution adopted by this invention to solve its first technical problem is a modified high-reflectivity, low-thermal-conductivity insulating surface coating, which is composed of the following components: 20-30 parts of acrylic resin, 20-30 parts of hyperbranched modified acrylic resin, 15-20 parts of titanium dioxide, 15-20 parts of non-electric cooling powder, 5-20 parts of infrared reflective pigment, 5-10 parts of xylene, 5-10 parts of butyl acetate, 5-10 parts of ethyl acetate, 0.5-1 part of dispersant, 0.5-1 part of organic rheology modifier, and 0.1-0.5 parts of fumed silica.

[0007] Acrylic resin and hyperbranched modified acrylic resin are used as film-forming substances, providing high resistance to accelerated aging and decorative and protective functions after film formation. Dispersants act as wetting and dispersing agents. Organic rheology modifiers and fumed silica are used as anti-settling agents in the formulation. 895 titanium dioxide, electroless cooling powder, and infrared reflective pigments are used as functional pigments and fillers to primarily improve solar reflectance, hemispherical reflectance, and near-infrared reflectance. Xylene, ethyl acetate, and butyl acetate are used as solvents for the resin components, facilitating the mixing of the resin, infrared reflective pigments, and additives.

[0008] It should be noted that fumed silica is the anti-settling agent in this invention. The appropriate amount of silica added is beneficial to the full and uniform mixing between the resin and the functional pigments and fillers. However, excessive addition will cause the viscosity of this invention to increase rapidly.

[0009] Furthermore, the acrylic resin has a solid content of 60-80 wt% and is provided by Changxing Chemical Co., Ltd.

[0010] Furthermore, the hyperbranched modified acrylic resin has a solid content of 50–70 wt%. The purpose of adding the hyperbranched modified acrylic resin is to increase the solar reflectance and improve its stain resistance.

[0011] The preparation process of hyperbranched modified acrylic resin includes:

[0012] Add 400-450 parts of alkyd resin to the reactor, add xylene and butyl acetate as solvents, and start stirring; purge with nitrogen for 20-40 min, and heat to 115-120℃ and keep at a constant temperature.

[0013] At room temperature, 150-180 parts of methyl methacrylate (MMA), 80-100 parts of butyl acrylate (BA), 5-8 parts of acrylic acid (AA), 10-15 parts of hydroxyethyl methacrylate (HEMA), 20-30 parts of trimethylolpropane triacrylate (TMPTA), and 8-10 parts of initiator are placed in a titration vessel and mixed evenly to obtain a mixture for later use.

[0014] Add 10% of the mixture to the reactor and prepolymerize at 110-130℃ for 20-40 min to stabilize the system and prevent gelation. Add the remaining mixture dropwise at a uniform rate over 5-7 hours, maintaining the temperature at 118-122℃ for 2-4 hours. Cool down to below 60℃, add the polymerization inhibitor, stir for 10-20 min, filter, and the product is obtained.

[0015] It should be noted that initiators and polymerization inhibitors are common reagents in resin modification, and commonly used initiators and polymerization inhibitors in this field are sufficient. There are no restrictions on the amount and ratio of xylene and butyl acetate, as long as they can dissolve the alkyd resin.

[0016] Furthermore, the dispersant is a high molecular weight block copolymer or a modified polyurethane polymer, wherein the high molecular weight block copolymer is BYK161 or BYK163, and the modified polyurethane polymer is AFCONA4010 (Evcana).

[0017] Furthermore, the titanium dioxide is rutile titanium dioxide.

[0018] In this invention, the non-electric cooling powder is a special non-electric cooling composite pigment composed of nano-inorganic materials with high band gap and high refractive index. The non-electric cooling powder in the embodiments is provided by Shure Shield, Aorun New Materials or Kedeli.

[0019] In this invention, the infrared reflective pigment is a metal-mixed oxide or perovskite matrix pigment that achieves a cooling function by selectively reflecting near-infrared light, while simultaneously absorbing visible light (380-780nm) to display color. The infrared reflective pigment in the embodiments was provided by Aorun New Materials or Dongjia.

[0020] Rutile titanium dioxide has a reflectance >0.9 in the 380-780nm wavelength range, while infrared reflective pigments have a significantly higher reflectance than ordinary titanium dioxide in the 1200-1500nm wavelength range. Using them together can improve the reflectance across the entire spectrum. Electro-cooled powders possess high emissivity, high reflectivity, and low thermal conductivity. In the 8-13nm wavelength range, they can efficiently convert heat from the surface of an object into infrared radiation of a specific wavelength, dissipating heat into space through an "atmospheric window." This invention utilizes a compound of electro-cooled powder, infrared reflective pigments, and titanium dioxide for synergistic enhancement, improving the thermal insulation effect.

[0021] The technical solution adopted by this invention to solve its second technical problem is a method for preparing a modified high-reflectivity heat-insulating surface coating, comprising the following steps:

[0022] Step (1) Preparation of acrylic solution: Add acrylic resin and hyperbranched modified acrylic resin to a stirred tank, then add butyl acetate, ethyl acetate and xylene in sequence; stir evenly; then let stand to obtain a clear and transparent acrylic resin solution.

[0023] Step (2) Add dispersant, fumed silica and organic rheology modifier to the acrylic resin solution obtained in step (1), stir until uniform, and obtain a mixed solution;

[0024] Step (3) Add 895 titanium dioxide, non-electric cooling powder, and infrared reflective pigment to the mixed solution obtained in step (2); stir evenly to obtain the modified high reflective heat insulation surface coating.

[0025] Furthermore, in steps (1), (2) and (3), the stirring time is ≥30 min; the stirring speed is controlled at 1300~1500 rpm, and the stirring temperature is ≤60℃.

[0026] Furthermore, in step (3), the viscosity of the modified high-reflectivity heat-insulating surface coating is 100KU-150KU.

[0027] Beneficial effects of this invention:

[0028] This invention is designed for high-reflectivity cooling coating of containers. Based on the excellent film performance and long resistance to artificial accelerated aging of acrylic resin, it is selected as the main resin. Hyperbranched modified acrylic resin is used in a reasonable combination, and functional pigments and fillers with high-reflectivity cooling are added. This gives the coating the characteristics of high weather resistance, high reflectivity cooling, good wettability, and easy application. The solar reflectance is ≥0.86, hemispherical emissivity is ≥0.88, and near-infrared reflectance is ≥0.88.

[0029] The preparation method of the modified high-reflectivity heat-insulating surface coating of the present invention is simple and has low production cost. Detailed Implementation

[0030] The specific implementation of the present invention will be described in detail below. It should be noted that, unless otherwise stated, the numerical parameters listed below are approximate values ​​and can vary within a reasonable range to achieve the desired performance. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without further creative effort are considered to be within the scope of protection of the present invention.

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

[0032] The dispersant used in this embodiment and comparative example is AFCONA4010 from Evcana. Other raw materials or chemical reagents, unless otherwise specified, were obtained through conventional commercial channels.

[0033] Example 1

[0034] The modified high-reflectivity heat-insulating surface coating of this embodiment is composed of the following components: 20 parts acrylic resin, 20 parts hyperbranched acrylic resin, 1 part dispersant 4010, 0.6 parts 140W organic rheology modifier, 0.5 parts M-5 fumed silica, 20 parts non-electrically cooled powder (Shure Shield), 20 parts 895 titanium dioxide, 0.2 parts defoamer, 5 parts infrared reflective pigment (Aorun New Materials), 5 parts xylene, 2.7 parts ethyl acetate, and 5 parts butyl acetate.

[0035] The preparation process of hyperbranched modified acrylic resin includes:

[0036] Add 450 parts of alkyd resin to the reactor, add xylene and butyl acetate as solvents, and start stirring; purge with nitrogen for 20 min, and heat to 120℃ and keep at a constant temperature.

[0037] At room temperature, 180 parts of methyl methacrylate (MMA), 100 parts of butyl acrylate (BA), 8 parts of acrylic acid (AA), 10 parts of hydroxyethyl methacrylate (HEMA), 20 parts of trimethylolpropane triacrylate (TMPTA), and 8 parts of initiator were placed in a titration vessel and mixed evenly to obtain a mixture for later use.

[0038] Add 10% of the mixture to the reactor and prepolymerize at 110℃ for 40 min to stabilize the system without gelation; add the remaining mixture dropwise at a uniform rate over 5 hours, maintaining the temperature at 122℃ for 2 hours; cool down to below 60℃, add the polymerization inhibitor and stir for 10 min, filter and discharge to obtain the final product.

[0039] The preparation method of the modified high-reflectivity heat-insulating and anti-corrosion surface coating includes the following steps:

[0040] (1) Preparation of acrylic solution: Add 20 parts of acrylic resin and 20 parts of hyperbranched modified acrylic resin to a stirring vessel according to the weight, then add 5 parts of butyl acetate, 2.7 parts of ethyl acetate and 5 parts of xylene in sequence; stir for 30 min; control the speed of the stirrer at 1300 rpm and the stirring temperature at 50℃; then let stand to obtain a clear and transparent acrylic resin solution.

[0041] (2) Preparation of acrylic acid mixture: In step (1), add 1 part dispersant 4010, 0.6 parts 140W organic rheology modifier, 0.5 parts M-5 fumed silica and 0.2 parts defoamer to the acrylic acid solution by weight; stir for 30 min; control the speed of the stirrer at 1300 rpm and the stirring temperature at 50℃; then let stand to obtain acrylic resin mixture;

[0042] (3) Add 20 parts of non-electric cooling powder, 20 parts of 895 titanium dioxide and 5 parts of infrared reflective pigment to the acrylic mixture obtained in step (2) by weight; stir for 30 minutes; control the speed of the mixer at 1500 rpm and the stirring temperature at 60℃; stir evenly and it is ready.

[0043] Example 2

[0044] The modified high-reflectivity heat-insulating surface coating of this embodiment is composed of the following components: 20 parts acrylic resin, 20 parts hyperbranched modified acrylic resin, 1 part dispersant 4010, 0.6 parts 140W organic rheology modifier, 0.5 parts M-5 fumed silica, 20 parts non-electrically cooled powder (Kodeli), 20 parts 895 titanium dioxide, 0.2 parts defoamer, 5 parts infrared reflective pigment (Dongjia), 5 parts xylene, 2.7 parts ethyl acetate, and 5 parts butyl acetate.

[0045] The preparation process of hyperbranched modified acrylic resin includes:

[0046] Add 400 parts of alkyd resin to the reactor, add xylene and butyl acetate as solvents, and start stirring; purge with nitrogen for 40 min, and heat to 115℃ and keep at a constant temperature.

[0047] At room temperature, 150 parts of methyl methacrylate (MMA), 80 parts of butyl acrylate (BA), 5 parts of acrylic acid (AA), 10 parts of hydroxyethyl methacrylate (HEMA), 30 parts of trimethylolpropane triacrylate (TMPTA), and 10 parts of initiator were placed in a titration vessel and mixed evenly to obtain a mixture for later use.

[0048] Add 10% of the mixture to the reactor and prepolymerize at 130℃ for 20 min to stabilize the system without gelation; add the remaining mixture dropwise at a uniform rate over 7 hours, maintaining the temperature at 118℃ for 4 hours; cool down to below 60℃, add the polymerization inhibitor and stir for 20 min, then filter and discharge to obtain the final product.

[0049] A method for preparing a modified high-reflectivity heat-insulating surface coating includes the following steps:

[0050] (4) Preparation of acrylic resin solution: Add 20 parts acrylic resin and 20 parts acrylic resin to a mixing tank by weight, then add 5 parts butyl acetate, 2.7 parts ethyl acetate and 5 parts xylene in sequence; stir for 30 min; control the speed of the mixer at 1300 rpm and the stirring temperature at 50℃; then let stand to obtain a clear and transparent acrylic resin solution.

[0051] (5) Preparation of acrylic acid mixture: In step (1), add 1 part dispersant 4010, 0.6 parts 140W organic rheology modifier, 0.5 parts M-5 fumed silica and 0.2 parts defoamer to the acrylic acid solution by weight; stir for 30 min; control the speed of the stirrer at 1300 rpm and the stirring temperature at 50℃; then let stand to obtain acrylic resin mixture;

[0052] (6) Add 20 parts of non-electrically cooled powder, 20 parts of 895 titanium dioxide and 5 parts of infrared reflective pigment to the acrylic mixture obtained in step (2) by weight; stir for 30 minutes; control the speed of the mixer at 1500 rpm and the stirring temperature at 60℃; stir evenly and it is ready.

[0053] Example 3

[0054] The modified high-reflectivity heat-insulating surface coating of this embodiment is composed of the following components: 20 parts acrylic resin, 20 parts hyperbranched modified acrylic resin, 1 part dispersant 4010, 0.6 parts 140W organic rheology modifier, 0.5 parts M-5 fumed silica, 20 parts non-electrically cooled powder (Aorun New Materials), 20 parts 895 titanium dioxide, 0.2 parts defoamer, 5 parts infrared reflective pigment (Aorun New Materials), 5 parts xylene, 2.7 parts ethyl acetate, and 5 parts butyl acetate.

[0055] The preparation process of hyperbranched modified acrylic resin includes:

[0056] Add 420 parts of alkyd resin to the reactor, add xylene and butyl acetate as solvents, and start stirring; purge with nitrogen for 30 min, and heat to 120℃ and keep at a constant temperature.

[0057] At room temperature, 170 parts of methyl methacrylate (MMA), 90 parts of butyl acrylate (BA), 6 parts of acrylic acid (AA), 12 parts of hydroxyethyl methacrylate (HEMA), 25 parts of trimethylolpropane triacrylate (TMPTA), and 9 parts of initiator were placed in a titration vessel and mixed evenly to obtain a mixture for later use.

[0058] Add 10% of the mixture to the reactor and prepolymerize at 120℃ for 30 min to stabilize the system without gelation; add the remaining mixture dropwise at a uniform rate over 6 hours, maintaining the temperature at 120℃ for 3 h; cool down to below 60℃, add the polymerization inhibitor and stir for 15 min, filter and discharge to obtain the final product.

[0059] A method for preparing a modified high-reflectivity heat-insulating surface coating includes the following steps:

[0060] (7) Preparation of acrylic resin solution: Add 20 parts acrylic resin and 20 parts acrylic resin to a stirring vessel by weight, then add 5 parts butyl acetate, 2.7 parts ethyl acetate and 5 parts xylene in sequence; stir for 30 min; control the stirring speed at 1300 rpm and the stirring temperature at 50℃; then let stand to obtain a clear and transparent acrylic resin solution.

[0061] (8) Preparation of acrylic acid mixture: In step (1), add 1 part dispersant 4010, 0.6 parts 140W organic rheology modifier, 0.5 parts M-5 fumed silica and 0.2 parts defoamer to the acrylic acid solution by weight; stir for 30 min; control the speed of the stirrer at 1300 rpm and the stirring temperature at 50℃; then let stand to obtain acrylic resin mixture;

[0062] (9) Add 20 parts of non-electric cooling powder, 20 parts of 895 titanium dioxide and 5 parts of infrared reflective pigment to the acrylic mixture obtained in step (2) by weight; stir for 30 minutes; control the speed of the mixer at 1500 rpm and the stirring temperature at 60℃; stir evenly and it is ready.

[0063] Comparative Example 1

[0064] The difference from Example 3 is that 40 parts of acrylic resin and 0 parts of hyperbranched modified acrylic resin were used.

[0065] Comparative Example 2

[0066] The difference from Example 3 is that there are 0 parts of acrylic resin and 40 parts of hyperbranched modified acrylic resin.

[0067] The modified high-reflectivity heat-insulating and anti-corrosion surface coatings prepared in Examples 1-3 and Comparative Examples 1-2 were tested according to the container coating testing method, and the results are shown in Table 1.

[0068] Table 1

[0069]

[0070] As shown in the table above, Examples 1-3 have a solar reflectance ≥0.86, hemispherical emissivity ≥0.88, and near-infrared reflectance ≥0.88. They also exhibit a color change ≤2 level and gloss loss ≤20% after 1200 hours of accelerated aging, and a solar reflectance change rate ≤5% after contamination. In contrast, Comparative Example 1 has a solar reflectance ≤0.86, hemispherical emissivity ≤0.88, and near-infrared reflectance ≤0.86, and a solar reflectance change rate of 16% after contamination, which does not meet the requirements. Comparative Example 2 exhibits a gloss loss rate of 31.2% after 1200 hours of accelerated aging, which also does not meet the requirements.

[0071] Comparative Example 3

[0072] The difference from Example 3 is that it contains 0 parts of non-electrically cooled powder (Aorun New Materials), 40 parts of 895 titanium dioxide, and 5 parts of infrared reflective pigment (Aorun New Materials).

[0073] Comparative Example 4

[0074] The difference from Example 3 is that it contains 40 parts of non-electrically cooled powder (Aorun New Materials), 0 parts of 895 titanium dioxide, and 5 parts of infrared reflective pigment (Aorun New Materials).

[0075] Comparative Example 5

[0076] The difference from Example 3 is that it contains 20 parts of non-electrically cooled powder (Aorun New Materials), 25 parts of 895 titanium dioxide, and 0 parts of infrared reflective pigment (Aorun New Materials).

[0077] Example 3 and Comparative Examples 3-5: The modified high-reflectivity heat-insulating surface coatings prepared were tested according to the container coating testing method, and the results are shown in Table 2.

[0078] Table 2

[0079]

[0080] As shown in the table above, Example 3 exhibits a solar reflectance ≥0.86, hemispherical emissivity ≥0.88, and near-infrared reflectance ≥0.88. It also shows a color change ≤2 levels after 1200 hours of accelerated aging, gloss loss ≤20%, and a solar reflectance change rate ≤5% after contamination. Comparative Example 3, however, has a hemispherical emissivity ≤0.88, failing to meet the requirements; Comparative Example 4 has a solar reflectance ≤0.86, failing to meet the requirements; and Comparative Example 5 has a near-infrared emissivity ≤0.86, failing to meet the requirements. Rutile titanium dioxide ensures a high solar reflectance, near-infrared reflective powder significantly improves the near-infrared reflectance of the coating, and the non-electro-cooled powder significantly improves the hemispherical emissivity of the coating. The combination of these three components achieves the technical specifications required by Examples 1-3.

[0081] Examples 1-3 describe modified high-reflectivity heat-insulating surface coatings for containers. These coatings possess advantages such as high solar reflectance, high hemispherical emissivity, high near-infrared reflectance, long weather resistance, and pollution resistance, thus fulfilling the reflective heat insulation and cooling effects required for container coating.

Claims

1. A modified high-reflectivity heat-insulating surface coating, characterized in that, By weight, its raw material components include: 20-30 parts acrylic resin, 20-30 parts hyperbranched modified acrylic resin, 15-20 parts titanium dioxide, 15-20 parts non-electric cooling powder, 5-20 parts infrared reflective pigment, 5-10 parts xylene, 5-10 parts butyl acetate, 5-10 parts ethyl acetate, 0.5-1 part dispersant, 0.5-1 part organic rheology modifier, and 0.1-0.5 parts fumed silica.

2. The modified high-reflectivity heat-insulating surface coating according to claim 1, characterized in that, The acrylic resin has a solid content of 60-80 wt%.

3. The modified high-reflectivity heat-insulating surface coating according to claim 1, characterized in that, The hyperbranched modified acrylic resin has a solid content of 50–70 wt%.

4. The modified high-reflectivity heat-insulating surface coating according to claim 1, characterized in that, The dispersant is a high molecular weight block copolymer or a modified polyurethane polymer.

5. The modified high-reflectivity heat-insulating surface coating according to claim 1, characterized in that, The 895 titanium dioxide is a rutile titanium dioxide.

6. The method for preparing the modified high-reflectivity heat-insulating surface coating according to any one of claims 1-5, characterized in that, Includes the following steps: (1) Preparation of acrylic solution: Add acrylic resin and hyperbranched modified acrylic resin to a stirred tank, then add butyl acetate, ethyl acetate and xylene in sequence; stir evenly; then let stand to obtain a clear and transparent acrylic resin solution. (2) Add dispersant, fumed silica and 140W organic rheology modifier to the acrylic resin solution obtained in step (1), stir until uniform, and obtain a mixed solution; (3) Add titanium dioxide, non-electric cooling powder and infrared reflective pigment to the mixed solution obtained in step (2); stir evenly to obtain the modified high reflective heat insulation surface coating.

7. The preparation method according to claim 6, characterized in that, In steps (1), (2) and (3), the stirring time is ≥30 min; the stirring speed is controlled at 1300~1500 rpm, and the stirring temperature is ≤60℃.

8. The preparation method according to claim 6, characterized in that, In step (3), the viscosity of the modified high-reflectivity heat-insulating surface coating is 100KU-150KU.

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