High reflectivity pigments for building exteriors

Abstract

This invention belongs to the technical field of architectural coatings, specifically relating to a high-reflectivity pigment for exterior building walls. The invention comprises coated glass microspheres, a pigment, modified silica, a resin, an additive, and water. The modified silica is silica coated with vinyltriethoxysilane, and the coated glass microspheres are hollow glass microspheres coated with titanium dioxide. By adding the coated hollow glass microspheres and modified silica to the coating formulation, and working in conjunction with various other ingredients, the coating achieves excellent weather resistance while maintaining high reflectivity.

Description

Technical Field

[0001] The invention belongs to the technical field of building coatings, and in particular relates to a high-reflectivity pigment for building exterior walls. Background Art

[0002] The building exterior wall is the main component of the building's external protective structure. It is in direct contact with the external environment and plays the role of enclosure, load-bearing, thermal insulation, waterproofing and moisture-proofing, sound insulation and noise reduction, aesthetics, and fire prevention.

[0003] During the summer heatwave, untreated buildings absorb solar heat, causing internal temperatures to rise. This increases the energy consumption of indoor appliances such as air conditioners and refrigerators. Conversely, in the winter, untreated building surfaces tend to conduct heat away from the interior, reducing heating efficiency and further increasing energy consumption.

[0004] Pigments for building exterior walls with high light reflectivity can not only be beautiful but also effectively reflect ultraviolet and infrared rays in sunlight, reduce the heat absorbed by the building, and achieve energy-saving effects.

[0005] At the same time, reducing heat absorption can reduce the thermal stress and aging rate of building materials (such as concrete, wood, etc.), thereby extending the service life of buildings and their internal facilities.

[0006] Therefore, it is necessary to further optimize the currently available pigments to achieve better results. Summary of the Invention

[0007] The invention provides a high-reflectivity pigment for building exterior walls, which has the dual functions of coating glass microspheres and modified silicon dioxide, thereby improving the light reflectivity of the pigment.

[0008] A high-reflectivity pigment for building exterior walls, comprising the following components by mass percentage:

[0009]

[0010] The modified silica is silica coated with vinyltriethoxysilane;

[0011] The coated glass microspheres are hollow glass microspheres coated with titanium dioxide.

[0012] Preferably, the preparation method of the modified silicon dioxide is:

[0013] The silicon dioxide is dispersed in ethanol, and water and ammonia water are added; vinyl triethoxysilane is then added and heated to react for a period of time; after the reaction, the modified silicon dioxide is washed and dried to obtain the modified silicon dioxide.

[0014] Preferably, the mass ratio of silicon dioxide to vinyltriethoxysilane is 1:0.2-0.4.

[0015] The mass ratio of the silicon dioxide to ethanol, water and ammonia water is 1:10-15:2-3:2-3.

[0016] The reaction temperature is 65-85°C and the reaction time is ≥6h.

[0017] Further preferably, the mass ratio of silicon dioxide to vinyltriethoxysilane is 1:0.3;

[0018] The mass ratio of silicon dioxide to ethanol, water and ammonia is 1:15:2:2;

[0019] The reaction temperature was 80°C and the reaction time was 6 h.

[0020] Preferably, the resin includes at least one of the following: acrylic acid, polyvinyl acetate, and silicone acrylic emulsion.

[0021] Preferably, the auxiliary agent includes at least one of the following:

[0022] Defoaming agent, dispersant, thickener, antifreeze agent, wetting agent, film-forming aid.

[0023] The formulation of the present invention takes into account the synergistic effect of multiple ingredients and is intended to improve the reflectivity and weather resistance of exterior wall coatings while maintaining their aesthetics and functionality.

[0024] The vinyltriethoxysilane (VTES)-coated silica used in this invention helps improve the pigment's weather resistance, adhesion, and reflective properties; the coating enhances the stability of the silica particles in the coating. The inventors found that this coating offers the best reflectivity enhancement compared to 3-aminopropyltriethoxysilane (APTES), methyltrimethoxysilane (MTMS), and dodecyltriethoxysilane (DTES).

[0025] The second special raw material used in the present invention is hollow glass microspheres coated with titanium dioxide, which helps to improve the reflectivity of the pigment; the coated glass microspheres can further improve their reflectivity of visible light and near-infrared light, achieving better thermal insulation performance.

[0026] However, if too much coated hollow glass microspheres are used, it may interfere with the adhesion between the coating and the substrate; more importantly, the color of the pigment will be interfered with by titanium dioxide, and the required color level cannot be achieved.

[0027] If uncoated hollow glass microspheres are used, the amount of added microspheres needs to be increased, which will lead to problems such as uneven surface and decreased adhesion.

[0028] At the same time, the present invention has found that there is a certain synergistic effect when the coated hollow glass microspheres and modified silica are used simultaneously. When the addition amounts are equal, the reflectivity is obviously higher.

[0029] The invention adds auxiliary agents such as defoaming agent and dispersant, which helps to improve the construction performance of the coating and the appearance quality of the final coating.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention adds coated hollow glass microspheres and modified silicon dioxide to the coating formula, and works together with multiple ingredients to achieve good weather resistance of the coating while maintaining high reflectivity. DETAILED DESCRIPTION

[0032] In order to better understand the present invention, the present invention is further described below in conjunction with specific serial numbers, wherein the terms used in the serial numbers are for describing specific embodiments and do not constitute a limitation on the scope of protection of the present invention.

[0033] In the specific implementation manner, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0034] The sources of some raw materials used in the present invention are shown in Table 1 below:

[0035] Table 1

[0036] name Product Name / Model / Other Name Source (Manufacturer) Coated glass beads Titanium dioxide coated hollow glass microspheres Wanhua Chemical Glass beads 400 mesh hollow glass beads Hebei Huishun Mining Co., Ltd. Silicon dioxide Fumed silica KS-A200 Shandong Kasong New Materials Co., Ltd. ethanol Anhydrous ethanol Guangzhou Chemical Reagent Factory ammonia Ammonia (analytical grade) Guangzhou Chemical Reagent Factory Vinyltriethoxysilane / Shandong Yuanjin New Materials Co., Ltd. 3-Aminopropyltriethoxysilane / Shandong Yuanjin New Materials Co., Ltd. Methyltrimethoxysilane / Shandong Yuanjin New Materials Co., Ltd. Dodecyltriethoxysilane / Shandong Yuanjin New Materials Co., Ltd. acrylic resin Thermoplastic acrylic resin Shandong Yuanjin New Materials Co., Ltd. polyvinyl acetate / Shandong Yuanjin New Materials Co., Ltd. Silicone acrylic emulsion / Shandong Shengkai Chemical Co., Ltd. defoaming agent / Jinan Sunny Chemical Technology Co., Ltd. dispersants / Jinan Sunny Chemical Technology Co., Ltd. thickener / Jinan Sunny Chemical Technology Co., Ltd. antifreeze / Jinan Sunny Chemical Technology Co., Ltd. Wetting agent / Jinan Sunny Chemical Technology Co., Ltd. Coal-forming aids / Jinan Sunny Chemical Technology Co., Ltd. Pigments 4352 Phthalocyanine Blue B Guangzhou Meidan Titanium Dioxide Co., Ltd.

[0037] Example 1 The preparation of modified silicon dioxide comprises the following steps:

[0038] (1) Place the resin in a high-speed blender, disperse the silica in ethanol, add water and ammonia, and stir for at least 30 minutes;

[0039] (2) Add silane and heat to react for a period of time;

[0040] (3) After the reaction is completed, the product is washed with ethanol and dried in vacuum to obtain modified silica.

[0041] The specific reaction conditions and addition amounts of Example 1 are shown in Table 2 below:

[0042] Table 2 Modified silica reaction parameters

[0043]

[0044] Note: " / " in Table 2 indicates that no addition or inapplicability is made, and the raw materials are from the manufacturers and corresponding models written in Table 1. Example 2 Preparation of a high reflectivity paint for building exterior walls, comprising the following steps:

[0045] (1) Place the resin in a high-speed mixer, add additives, and continue stirring;

[0046] (2) adding solid components such as glass microspheres and modified silica;

[0047] (3) Add pigment and water and stir evenly to obtain high reflectivity paint for building exterior walls.

[0048] Example 2 The specific reaction conditions and addition amounts are shown in Table 3 below:

[0049] Table 3 Reaction parameters of high reflectivity pigments for building exterior walls

[0050]

[0051]

[0052] Table 3 Reaction parameters of high reflectivity pigments for building exterior walls (continued)

[0053]

[0054] Note: “ / ” in Table 3 indicates that no addition or inapplicability is used. The raw materials are from the manufacturers and corresponding models listed in Table 1. The modified silica group is from the corresponding group in Table 2 in Example 1.

[0055] Performance test

[0056] The high reflectivity exterior building wall pigment prepared in Example 2 was subjected to relevant performance tests:

[0057] 1. Solar reflectance (TSR): Based on JG / T 235-2014 "Architectural Reflective Thermal Insulation Coatings";

[0058] 2. Storage stability: Based on GB / T 9268-2008 "Determination of freeze-thaw resistance of latex paint";

[0059] 3. Construction performance: Based on GB / T 9755-2014 "Synthetic resin emulsion exterior wall coating";

[0060] 4. Abrasion resistance: GB / T 1768-2006 “Paints and varnishes - Determination of abrasion resistance - Rotating rubber grinding wheel method”;

[0061] The results are shown in Table 4 below.

[0062] Table 4 Performance test of high reflectivity paint for building exterior walls

[0063]

[0064]

[0065] The results in Table 4 show that when uncoated glass microspheres are used (Group 7), the reflectivity decreases significantly. By comparing Group 1 with Groups 8, 9, and 10, when 3-aminopropyltriethoxysilane (APTES), methyltrimethoxysilane (MTMS), and dodecyltriethoxysilane (DTES) are used for coating, the reflectivity is poor. The results of Group 11 show that when unmodified silica is used, not only does it cause a decrease in solar reflectivity, but it also causes a decrease in wear resistance. The results of Group 12 show that when an excessive amount of coated glass microspheres is used, although the decrease in solar reflectivity is not obvious, the wear resistance is greatly reduced, ultimately leading to a decrease in service life.

[0066] The above detailed description is a specific description of one feasible embodiment of the present invention. This embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not depart from the present invention should be included in the scope of the technical solution of the present invention.

Claims

1. A high reflectivity pigment for building exterior walls, characterized in that: The following components are included by mass percentage: Coated glass beads 3-5% Pigment 0.01-20% Modified silica 2-5% Resin 30-50% Additives 2-10% Replenish water to 100% The modified silica is silica coated with vinyltriethoxysilane; The coated glass microspheres are hollow glass microspheres coated with titanium dioxide; The preparation method of the modified silicon dioxide is: Dispersing silica in ethanol, and adding water and ammonia water; then adding vinyl triethoxysilane and heating to react for a period of time; washing and drying after the reaction to obtain modified silica; The mass ratio of silica to vinyltriethoxysilane is 1:0.2-0.4; The mass ratio of silicon dioxide to ethanol, water and ammonia is 1:10-15:2-3:2-3; The reaction temperature is 65-85°C and the reaction time is ≥6h.

2. The high reflectivity exterior building wall pigment according to claim 1, wherein The mass ratio of silica to vinyltriethoxysilane is 1:0.3; The mass ratio of silicon dioxide to ethanol, water and ammonia is 1:15:2:2; The reaction temperature was 80°C and the reaction time was 6 h.

3. The high reflectivity pigment for building exterior walls according to claim 1, wherein The resin includes at least one of the following: polyvinyl acetate and silicone acrylic emulsion.

4. The high reflectivity pigment for building exterior walls according to claim 1, wherein The auxiliary agent includes at least one of the following: Defoaming agent, dispersant, thickener, antifreeze agent, wetting agent, film-forming aid.

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