US20170167807A1

US20170167807A1 - Heat shielding material, heat shielding composition and heat shielding structure employing the same

Info

Publication number: US20170167807A1
Application number: US15/343,406
Authority: US
Inventors: Huai-Kuang Fu; Pang-Hung Liu; Chia-Wei Chang; Yuan-Chang Huang; Ya-I HSU
Original assignee: Industrial Technology Research Institute ITRI
Current assignee: Industrial Technology Research Institute ITRI
Priority date: 2015-12-14
Filing date: 2016-11-04
Publication date: 2017-06-15

Abstract

A heat shielding material is provided. The heat shielding material includes a sheet material and a pigment layer covering the sheet material. The pigment layer includes a crosslinking structure formed of siloxane functional groups and pigments dispersed in the crosslinking structure. A heat shielding composition and a heat shielding structure employing the same are also provided.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-In-Part of pending U.S. patent application Ser. No. 14/984,297, filed Dec. 30, 2015 and entitled “Heat shielding material, heat shielding composition and heat shielding structure employing the same”. The present application is based on, and claims priority from, Taiwan Application Serial Number 104141877, filed on Dec. 14, 2015, and Taiwan Application Serial Number 105131235, filed on Sep. 29, 2016, the disclosure of which is hereby incorporated by reference herein in its entirety.

TECHNICAL FIELD

The disclosure relates to a heat shielding material, a heat shielding composition and a heat shielding structure employing the same.

BACKGROUND

Global warming causes extreme climate change around the world. Energy conservation and carbon reduction have become the most likely response strategies. So far, heat shielding materials are important green energy products used mainly in building roofs, exterior walls, and windows.
About 40% of sunlight enters buildings from roofs or exterior walls. A white roof is an ideal cool roof, because of its high solar reflectance. However, taking beauty and light pollution into consideration, in reality dark roofs are used more frequently. Because dark heat shielding materials rely on foreign imports, they are expensive and offer less choice. In addition, the current dark heat shielding coatings provide insufficient solar reflectance and heat resistance.
Therefore, improved heat shielding materials that conform to the demands of good solar reflectance and heat resistance are needed.

SUMMARY

An embodiment of the disclosure provides a heat shielding material, including a sheet material and a pigment layer covering the sheet material. The pigment layer includes a crosslinking structure formed of siloxane functional groups and pigments dispersed in the crosslinking structure.
Another embodiment of the disclosure provides a heat shielding composition, including 1 part by weight of the aforementioned heat shielding material and 0.1-300 parts by weight of a solvent.
Still another embodiment of the disclosure provides a heat shielding structure, including a substrate and a heat shielding layer disposed on the substrate. The heat shielding layer includes the aforementioned heat shielding material regularly arranged in a resin. The heat shielding materials are parallel to each other and substantially parallel to the surface of the substrate. The weight ratio between the heat shielding material and the resin is 0.02-10.
A detailed description is given in the following embodiments with reference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 is a cross-sectional view of a heat shielding material according to an exemplary embodiment;

FIG. 2 is a schematic view of a heat shielding material during the reaction process according to an exemplary embodiment; and

FIG. 3 is a cross-sectional view of a heat shielding structure according to an exemplary embodiment.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, or examples, for implementing different features of the subject matter provided. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
The quality of heat shielding coatings mainly depends on the solar reflectance (such as TSR) of the heat shielding coating. The TSR of white coatings is about 90%, and a coating film formed thereof can reflect most infrared (IR) light. In contrast, the TSR of black coatings is less than 10%, and a coating film formed thereof has a poor ability to reflect infrared (IR) light.
According to embodiments of the present disclosure, the present disclosure provides a heat shielding material, a heat shielding composition and a heat shielding structure employing the same. The heat shielding material of the present disclosure is a sheet material covered by a pigment layer. The heat shielding material is capable of improving the total solar reflectance (TSR) and decreasing the L-value of the resulting heat shielding composition and heat shielding structure, which may be widely applied to buildings, walls, roofs, or cars.
FIG. 1 is a cross-sectional view of a heat shielding material 100 according to an exemplary embodiment of the present disclosure. As shown in FIG. 1, an embodiment of the present disclosure provides a heat shielding material 100, including a sheet material 102 and a pigment layer 104. The pigment layer 104 covers the sheet material 102. According to some embodiments, the sheet material 102 used in the present disclosure may include mica, synthetic mica, hygrophilite, kaolin clay, montmorillonite, silicon dioxide, sheet metal oxides, slate flake, aluminum silicate salt, or a combination thereof. According to some embodiments, the sheet material 102 of the present disclosure may have an average particle size of 0.1-300 μm, for example, 5-80 μm. According to some embodiments, the sheet material 102 used in the present disclosure may have an average aspect ratio (a value of length/thickness) of 10-100, for example, 20-80. When the average aspect ratio of the sheet material 102 of the present disclosure is too high (i.e. more than 100), the dispersion is poor and the surface of the coating film is rough. In addition, when the average aspect ratio of the sheet material 102 of the present disclosure is too low (i.e. less than 10), the shielding ability is poor and the efficacy is insufficient.
In one embodiment of the present disclosure, the pigment layer 104 covering the sheet material 102 includes a crosslinking structure formed of siloxane functional groups and pigments dispersed in the crosslinking structure. According to some embodiments, the siloxane functional groups used in the present disclosure may have a chemical formula of Si(OR)₄. Each R may independently be H or alkyl group and the alkyl group may be C₁-C₈alkyl group, for example.
The aforementioned siloxane functional groups may include tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), n-octyltriethoxysilane, or a combination thereof. After being hydrolysed, the aforementioned siloxane functional groups may have OH groups. According to some embodiments, the pigments used in the present disclosure may include black pigments, red pigments, blue pigments, green pigments, yellow pigments, or a combination thereof. Each of these colored pigments may be used alone or in combination. In one embodiment, the combination ratio (weight ratio) of the black pigments and other colored pigments may be 0.1-5. The black pigments used in the present disclosure may include Aniline Black, Carbon Black, Shungite, Lamp black, Vine Black, Bone Black, Graphite, Mars Black, Iron Titanium Brown Spinel, Cobalt Black, Manganese Black, Chromium Green Black Hematite, Zinc Sulfide, Mineral Black, Slate Black, Tin Antimony Gray, Titanium Vanadium Antimony Gray, Cobalt Nickel Gray, Manganese Ferrite Black, Iron Cobalt Chromite Black, Copper Chromite Black, Iron Cobalt Black, Chrome Iron Nickel Black, Paliogen Black, Perylene Black, Iron Manganese Oxide, Molybdenum Disulfide, Titanium Dioxide Black, or a combination thereof.
The red pigments used in the present disclosure may include Toluidine Red, Permanent Red R, Naphthol Red DK, Permanent Red Y, Naphthol Crimson Red AS-TR, Permanent Red F4R, Naphthol AS Red, Permanent Bordeaux TRR, Toluidine Maroon, Permanent Bordeaux FGR, Permanent Maroon Medium, Pigment Red 17, Arylide Maroon, Pigment Red 21, Naphthol Red Bright, Naphthol Red Dark, Naphthol Red Extra Dark, Pigment Red 32, Pyrazolone Red, Arsenic Sulphide, Pigment Red 47, Permanent Red BB, Permanent Red BB [FIAT], Irgalite Red 2BY, Permanent Red 2B, Lithol Red LN, Barium Lithol Red, Calcium Lithol Red, Pigment Red 52.1, Pigment Red 52.2, Lake Red C, Pigment Lake Red C, Sodium Lithol Rubine, Lithol Rubine, Pigment Red 57:2, Pigment Red 58:4, Permanent Rose, Pigment Scarlet, Lake Caramine L, Pigment Carmine 3B, Pigment Red 63, Lithol Bordeaux, Lithol Red GG, Rhodamine 6G, Rhodamine 6G [FIAT], Rhodamine YS, Rhodamine YS PTMA, Alizarin Crimson, Alizarin Lake, Indo Red, Thioindigoid Violet, Vermilionette, Geranium lake, Pigment Red 89, Naphthol Red AS-D, Mercadium Red, Mercadium Lithopone Red, Pigment Red 114, Naphthol Red FG, Naphthol Red MEG-DR, Quinacridone Red, Perylene Scarlet, Azo Condensation Red, Permanent Carmine, Perylene Red BX, Pigment Red 150, Naphthol Carbamide, Anthradquinone Scarlet, Rhodamine, Naphthol Red AS, Naphthol Red, Benzimidazolone Bordeaux, D&C Red No.3 Aluminium Lake, Rhodamine Red, Pigment Red 174, Benzimidazolone Red HFT, Benzimidazolone Carmine, Anthraquinone Red, Perylene Maroon, Pigment Red 4BS, Pyrrole Red, Pyrazo Quinazo, Pyrrole Scarlet, Organic Nickel Violet, Shimura Fast Red, Pyrrole Red Rubine, or a combination thereof.
The blue pigments used in the present disclosure may include Victoria Blue, Victoria Blue SMA, Pigment Blue 9, Phthalocyanine Blue, Phthalocyanine Alfa Blue, Heliogen Blue L 7560, Phthalocyanine Cyan, Pigment Blue 25, Prussian Blue, Cobalt Blue, Ultramarine Blue, Copper Carbonate, Egyptian Blue, Smalt, Manganese Blue, Copper sulfide, Cerulean Blue, Cobalt Chromite, Zinc Cobalt Chrome Aluminum Spinel, Modorant Blue R, Reflex Blue A5L-G, Fastogen Blue 5007, Zirconium Vanadium Blue, Cobalt Zinc Aluminate Blue, Cobalt Silicate Blue, Chromofine Blue 5000P, Fastogen Blue 10GN, Aluminum Chloro-phthalocyanine, Hostaperm Blue RSR, Cobalt Tin Alumina Blue Spinel, or a combination thereof.
The green pigments used in the present disclosure may include Pigment Green 1, Fast Green Lake, 3606 Fast Green Lake, Phthalocyanine Green BS, Nitroso Green, Nickel Azo Yellow, Phthalochrome Green, Cadmium Green, Chrome Green, Zinc Green, Chrome Oxide Green, Chromium Green Black Hematite, Viridian, Cobalt Green, Verdigris, Emerald Green, Copper Arsenite, Green Earth, Ultramarine Green, Cobalt Chromite Green, Phthalocyanine Green YS, Copper Carbonate Hydroxide, Copper Ferrocyanide, Chromocyanine Green, Victoria Green Garnet, Nickel Green Olivine, or a combination thereof.
The yellow pigments used in the present disclosure may include Hansa Yellow G, Monolite Yellow G, Hansa Yellow GR, Hansa Yellow 10G, Arylide Yellow 13G, Hansa Yellow 5G, Hansa Yellow 3G, Azo Yellow 2GX, Hansa Yellow R, Benzidine Yellow G, Benzidine Yellow GR, Diarylide Yellow AAOT, Permanent Yellow NCG, Dairylide Yellow 17, C.I. Pigment Yellow 21, Flaventhrone Yellow, Lead Oxychloride, Barium Chromate, Strontium Chromate, Calcium Chromate, Lead Chromate, Lead Chromate with Lead sulfate, Cadmium Yellow, Cadmium lithopone Yellow, Zinc Yellow, Basic Zinc Yellow, Cadmium-Barium Yellow Deep, Tin Sulphide, Orpiment, Realgar, Aureoline, Naples Yellow, Yellow Iron Oxide, Natural Yellow Iron Oxide, Basic cadmium chromate, Iron Chromate, Massicot Litharge, Lead Titanate, Lead Cyanamide, Nickel Antimony Titanium Yellow Rutile, Diarylide Yellow AAPT, Pigment Yellow 61, Pigment Yellow 62, Pigment Yellow 62:1, Suimei Yellow 3G, Hansa yellow 65, Arylide Yellow GX, Arylide Yellow SGX, Arylide Yellow, Disazo Condensation Yellow, Diarylide Yellow H10G, Diarylide Yellow HR, Diarylide Yellow 1285, Disazo Yellow 3G, Cromophtal Yellow 6G, Disazo Yellow GR, Diarylide Yellow FGL, Diarylide Yellow, Tartrazine Lake, Lumogen Yellow, FD&C Yellow 6, D&C Yellow No. 10 lake, Anthrapyrimidine Yellow, Isoindole Yellow, Isoindolinone Yellow, Hansa Brilliant Yellow, Flavanthrone Yellow, Disazo Yellow 10HG, D&C Yellow 10, Helio Fast Yellow ER, Paliotol Yellow, Chromium Titan Yellow, Zinc Iron Yellow, PV Fast Yellow H2G, Diarylide Yellow DGR, Benzidine Yellow GRL, DCC Diarylide Yellow, Azo Condensation Yellow, Irgazin Yellow, Pigment Yellow 130, Pigment Yellow 133, Pigment Yellow 134, Pigment Yellow 136, Isoindoline Yellow, Quinophthalone Yellow, Pigment Yellow 147, Filamid Yellow 4G, Nickel Azo Yellow, Benzimidazolone Yellow H4G, Diarylide Yellow 152, Nickel Dioxime Yellow, Benzimidazolone Yellow 154, Benzimidazolone Yellow 155, Benzimidazolone Yellow 156, Daipyroxide Yellow, Tin Vanadium Yellow, Zirconium Praseodymium Silicate Yellow, Zirconium Vanadium Yellow, Nickel Niobium Titanium Yellow, Chrome Niobium Titanium Buff Rutile, Chromium Tungsten Titanium Buff, Manganese Antimony Titanium Buff Rutile, Sanyo Fast Yellow FSG, Chromofine Yellow, Seikafast Yellow A-3, Azo Yellow 168, Lionol Yellow K-2R, Pigment Yellow FRN, Lionol Yellow NBK, Irgalite Yellow LBT, Benzimidazolone Yellow H6G, Diaryl Yellow, Pigment Yellow 179, Benzimidazolone Yellow, Benzimidazo Golden, Sandorin Yellow, Paliotol Yellow K227, Bismuth Vanadate Yellow, Irgalite Yellow, Nickel Titanate, Paliotol Yellow K1570, Pigment Brilliant Yellow HGR, Cromophtal Yellow, Sandofil Yellow, Anthraquinone Yellow, Novoperm Yellow F2G, Sunglow Yellow, Pigment Yellow 204, Neolor Yellow, Solaplex Yellow, Titanium Zinc Antimony Stannate, or a combination thereof.
In one embodiment of the present disclosure, the pigment layer 104 and the sheet material 102 form a chemical bond such as Si—O—Si bonding through the siloxane functional groups. In addition, there is an intermolecular force between the pigments and the crosslinking structure, thus the pigments attach to and disperse in the crosslinking structure by this intermolecular force. Therefore, through the above chemical bond and intermolecular force, the pigment layer 104 formed of the pigments and the crosslinking structure may cover the sheet material 102 more completely and stably to assist in improving the TSR of the resulting heat shielding composition and heat shielding structure.
The heat shielding material 100 provided by the present disclosure may be formed by applying a sol-gel method. For example, the siloxane functional groups, acids, sheet materials, and pigments may be mixed first, and then a heating process is applied to the aforementioned mixture to form the previously described heat shielding material 100 of the present disclosure. For the purpose of explanation, specific examples are described below. However, the present disclosure is not intended to be limiting. In one embodiment, the siloxane functional groups may have a chemical formula of Si(OR)₄. Each R may independently be H or alkyl group.
In one embodiment of the present disclosure, tetraethoxysilane (TEOS), an acid, a sheet material 102, and pigments 106 are mixed, and then a heating process is applied to the aforementioned mixture to form the heat shielding material 100. In the reaction process, TEOS is reacted with the acid first to hydrolyze the four OR groups connected to Si into four OH groups. At this time, one of the OH groups reacts with an OH group on the surface of the sheet material 102 to form a hydrogen bonding. An intermolecular force is formed between the other three OH groups and the pigments 106, so that the pigments 106 are attached to the OH groups, as shown in FIG. 2. Next, a heating process is performed. A condensation reaction of the Si—OH of the siloxane functional groups produces Si—O—Si bonding, and thereby forms a crosslinking structure. The pigments 106 attached to the OH groups are trapped and dispersed in the crosslinking structure formed of the siloxane functional groups. At this time, the crosslinking structure and the pigments 106 dispersed therein together form a pigment layer 104. The pigment layer 104 covers the sheet material 102. In addition, during the sol-gel reaction, there are also Si—O—Si bondings formed between the surface of the sheet material 102 and the siloxane functional groups. Therefore, through this chemical bond, the pigment layer 104 may cover the sheet material 102 more completely and stably to assist in improving the TSR of the resulting heat shielding composition and heat shielding structure.
In one embodiment, the siloxane functional groups used in the present disclosure may be methyltriethoxysilane (MTES), n-octyltriethoxysilane, or a combination thereof. According to some embodiments, the acids used in the sol-gel reaction may include hydrochloric acid, nitric acid, acetic acid, sulfuric acid, or a combination thereof. According to some embodiments, the sheet material 102 may include mica, synthetic mica, hygrophilite, kaolin clay, montmorillonite, silicon dioxide, sheet metal oxides, slate flake, aluminum silicate salt, or a combination thereof. However, the sheet material 102 of the present disclosure is not limited thereto. As long as the sheet material has an average aspect ratio of 10-100, it may be applied to the present disclosure. According to some embodiments, the pigments 106 may include black pigments, red pigments, blue pigments, green pigments, yellow pigments, or a combination thereof. As for example, black pigments may include Aniline Black, Carbon Black, Shungite, Lamp black, Vine Black, Bone Black, Graphite, Mars Black, Iron Titanium Brown Spinel, Cobalt Black, Manganese Black, Chromium Green Black Hematite, Zinc Sulfide, Mineral Black, Slate Black, Tin Antimony Gray, Titanium Vanadium Antimony Gray, Cobalt Nickel Gray, Manganese Ferrite Black, Iron Cobalt Chromite Black, Copper Chromite Black, Iron Cobalt Black, Chrome Iron Nickel Black, Paliogen Black, Perylene Black, Iron Manganese Oxide, Molybdenum Disulfide, Titanium Dioxide Black, or a combination thereof. It should be noted that these examples are merely for illustration and the scope of the invention is not limited thereto.
In the present disclosure, the siloxane functional groups and acids are added to the reaction to increase the number of OH groups and make the pigments react with more OH groups. It has been found that it is difficult for hydrolysis to occur when the sheet material, siloxane functional groups, and pigments are directly mixed without adding acids, and therefore, a sol-gel reaction would not occur. Although an intermolecular force is formed between the pigments and the OH groups on the surface of the sheet material, the number of pigments attached to the surface of the sheet material is not high, since a steric hindrance is caused by the siloxane functional groups. Hydrolysis becomes faster when the sheet material, siloxane functional groups, and pigments are mixed with acids. In such cases, the sol-gel reaction occurs. Before the formation of the Si—O—Si bonding, the steric hindrance caused by the hydrolysed siloxane functional groups is small, and thus an intermolecular force is easily formed between the pigments and the OH groups on the surface of the sheet material. So, the pigments are attached to the sheet material. In addition, as described previously, the hydrolysed siloxane functional groups not only form a hydrogen bond with the OH group on the sheet material, the remaining OH groups of the hydrolysed siloxane functional groups may also have an intermolecular force with the pigments to make the pigments attach to the sheet material. As such, with the addition of acids, the pigments are able to react with more OH groups, and thereby cover the sheet material more completely.
Another embodiment of the present disclosure provides a heat shielding composition. In the present disclosure, the ratio between each reactant in the heat shielding composition may be adjusted depending on the desired properties of the heat shielding composition. For example, 1 part by weight of the previously described heat shielding material 100 and 0.1-300 parts by weight of the solvent may be used to form the heat shielding composition. Alternatively, 1 part by weight of the previously described heat shielding material 100 and 1-1000 parts by weight of the solvent may be used to form the heat shielding composition. According to some embodiments, the solvent used in the present disclosure may include methanol, ethanol, isopropanol, n-butanol, methyl ethyl ketone, acetone, cyclohexanone, methyl tertiary-butyl ketone, diethyl ether, ethylene glycol dimethyl ether, glycol ether, ethylene glycol monoethyl ether, tetrahydrofuran (THF), propylene glycol monomethyl ether acetate (PGMEA), ethyl-2-ethoxy ethanol acetate, 3-ethoxy propionate, isoamyl acetate, ethyl acetate, butyl acetate, chloroform, pentane, n-hexane, cyclohexane, heptane, benzene, toluene, xylene, or a combination thereof.
The heat shielding composition may further include a resin. The amount of resin may be adjusted depending on the desired properties of the heat shielding composition and the thickness of the coating layer formed thereof. For example, the amount of resin may be 0.1-60 parts by weight or 1-45 parts by weight. The resin used in the present disclosure may include polyester resin, polyimide resin, acrylic resin, epoxy resin, silicone resin, phenoxy resin, urethane resin, urea resins, acrylonitrile butadiene styrene resin (ABS resin), polyvinyl butyral resin (PVB resin), polyether resin, fluorine-containing resin, polycarbonate resin, polystyrene resin, polyamide resin, starch, cellulose, a copolymer thereof, or a mixture thereof. In addition, 0.1-3 parts by weight such as 0.5-2 parts by weight of dispersant may optionally be added into the above heat shielding composition to improve the TSR of the resulting heat shielding composition. The dispersant may be a polymer type dispersant, for example, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate copolymer mixture, ethylene acrylic acid copolymer, polyamide/oxidized polyethylene copolymer mixture, polyethylene copolymer, or a combination thereof
It should be noted that the heat shielding composition without dispersant already has a superior TSR than that of the commercial dark heat shielding material. However, the TSR of the heat shielding composition may further be improved by adding the dispersant. The results may be attributed to the heat shielding material easily having a single-direction arrangement in the existence of the dispersant.
FIG. 3 is a cross-sectional view of a heat shielding structure 200 according to an exemplary embodiment of the present disclosure. As shown in FIG. 3, an embodiment of the present disclosure provides a heat shielding structure 200, including a substrate 202 and a heat shielding layer 204 disposed on the substrate 202. The heat shielding layer 204 includes the previously described heat shielding material 100 regularly arranged in a resin 206. The weight ratio between the heat shielding material 100 and the resin 206 is 0.02-10. The heat shielding materials 100 are parallel to each other and substantially parallel to a surface of the substrate 202. It should be noted that the heat shielding materials 100 that are substantially parallel to a surface of the substrate 202 may represent that an angle between the plane direction of the heat shielding material 100 and the surface of the substrate 202 is no more than 10 degrees.
According to some embodiments, the substrate 202 of the present disclosure may be any solid substrate, for example, rigid substrate, including metal, iron plate, steel plate, galvanized steel, aluminum alloy, magnesium alloy, lithium alloy, semiconductor, glass, ceramics, cement, roof tile, silicon substrate, or for example, flexible substrate, including plastic substrate such as PES (polyethersulfone), PEN (polyethylenenaphthalate), PE (polyethylene), PI (polyimide), PVC (polyvinyl chloride), PET (polyethylene terephthalate), resin, or a combination thereof. The resin 206 used in the present disclosure may include polyester resin, polyimide resin, acrylic resin, epoxy resin, silicone resin, phenoxy resin, urethane resin, urea resins, acrylonitrile butadiene styrene resin (ABS resin), polyvinyl butyral resin (PVB resin), polyether resin, fluorine-containing resin, polycarbonate resin, polystyrene resin, polyamide resin, starch, cellulose, a copolymer thereof, or a mixture thereof.
In the present disclosure, the thickness of the heat shielding layer 204 may be adjusted depending on different applications to obtain a heat shielding structure with the desired properties. For example, the heat shielding layer 204 may have a thickness of 50-1000 nm or 200-600 nm. In addition, a dispersant may optionally be added to the heat shielding layer 204 to improve the TSR of the resulting heat shielding layer 204. The dispersant may be a polymer type dispersant, for example, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate copolymer mixture, ethylene acrylic acid copolymer, polyamide/oxidized polyethylene copolymer mixture, polyethylene copolymer, or a combination thereof. The weight ratio between the heat shielding material 100 and the dispersant may be 0.3-10, such as 0.5-5.
It should be noted that since the heat shielding material 100 of the present disclosure is a two-dimensional structure, specific coating processes may be used to coat the heat shielding layer 204 onto the substrate 202 to make sure that the heat shielding material 100 is regularly arranged on the substrate 202. For example, the coating processes for regular arrangement may include blade coating, bar coating, wire bar coating, brush coating, roller coating, spray coating, flow coating, other applicable coating processes for regular arrangement, or a combination thereof. In one embodiment of the present disclosure, the L-value of the resulting heat shielding structure 200 may be less than 30, for example, less than 25 or less than 20. In one embodiment of the present disclosure, the TSR of the resulting heat shielding structure 200 may be more than 20%, for example, more than 30%, more than 35%, more than 40%, or more than 45%.
The heat shielding material provided in the present disclosure is formed by reacting the siloxane functional groups, acids, sheet materials, and pigments in a sol-gel reaction by one step. Thus, the process is easier. Steps such as coating the coating material including pigments onto the inner material and a subsequent curing are not required. Also, the resulting heat shielding material formed in the present disclosure makes the pigment layer cover the sheet material more completely and stably. In addition, the resulting heat shielding structure has a high TSR (>20%), a high heat shielding property, and a low L-value (L<30). Therefore, the present disclosure provides a heat shielding material with sufficient TSR and heat shielding property.
Below, examples and comparative examples will be described in detail so as to be easily realized by a person having ordinary knowledge in the art.

EXAMPLE 1

1 g of tetraethoxysilane (TEOS), 1 g of Mica M (average particle size: 5.72 μm; average aspect ratio: 23.83), and 1 g of black pigments (BASF Paliogen 50084) were added to 100 mL of isopropanol (IPA) and thoroughly mixed. Then, 0.5 mL, 0.1 N of hydrochloric acid was added to the mixture. Next, a sol-gel reaction was performed for 3 hours at room temperature (25° C.), then warmed up to 80° C. for an additional 3 hours to form a heat shielding material.

EXAMPLE 2

1 g of tetraethoxysilane (TEOS), 1 g of Mica M (average particle size: 5.72 μm; average aspect ratio: 23.83), 0.05 g of black pigments (BASF Paliogen S0084), and 0.05 g of red pigments (Pigment Red 224) were added to 100 mL of isopropanol (IPA) and thoroughly mixed. Then, 0.5 mL, 0.1 N of hydrochloric acid was added to the mixture. Next, a sol-gel reaction was performed for 3 hours at room temperature (25° C.), then warmed up to 80° C. for an additional 6 hours to form a heat shielding material.

COMPARATIVE EXAMPLE 1

The same process described in Example 1 was repeated, except that Mica M was replaced by spherical titanium dioxide (TiO₂) micro particles (average particle size: 0.45 μm).

COMPARATIVE EXAMPLE 2

Comparative Example 2 was commercial heat shielding nanoparticles (spherical particles, Shepherd 10C909A).
ISO 9050 (Glass in building—Determination of light transmittance, solar direct transmittance, total solar energy transmittance, ultraviolet transmittance and related glazing factors) was used to determine the TSR of the heat shielding material of Example 1 and Comparative Example 1 and the commercial heat shielding nanoparticle of Comparative Example 2. ASTM D1003 was used to determine the haze of the heat shielding material of Example 1 and Comparative Example 1 and the commercial heat shielding nanoparticles of Comparative Example 2. The L-value was then calculated. L-value is between 1 and 100 and is used to represent the brightness of color. The higher the L-value is, the brighter the color is. The lower the L-value is, the darker the color is. The results of the TSR and L-value are shown in Table 1.

TABLE 1

Comparison of different heat shielding materials

		Sheet material	TSR (%)	L-value

Example 1	Mica M	47.2	24.8
Example 2	Mica M	39.1	28.7
Comparative	TiO₂micro particles	46.7	36.8
Example 1
Comparative	Commercial heat	21.3	25.7
Example 2	shielding nanoparticles

As shown in Table 1, when Mica M was used as the sheet material, the resulting heat shielding material had the highest TSR and the lowest L-value. TiO₂micro particles and Mica M have similar particle size and color (white). Although the TSR of the heat shielding materials formed by TiO₂micro particles and Mica M were close, the L-value of the heat shielding materials formed by Mica M was apparently smaller. Compared to the commercial heat shielding nanoparticle, the TSR of the heat shielding materials formed by Mica M was apparently larger.

EXAMPLE 3

The same process as described in Example 1 was repeated, except that Mica M was replaced by synthetic mica.

EXAMPLE 4

The same process described in Example 1 was repeated, except that Mica M was replaced by hygrophilite.

TABLE 2

Comparison of the resulting heat shielding material formed
by sheet material with different average aspect ratios

	Average	Average
	particle size	Aspect
Sheet material	(μm)	ratio	TSR (%)	L-value

Example 1	Mica M	5.72	23.83	47.2	24.8
Example 3	synthetic mica	23.0	70.55	46.5	28.9
Example 4	hygrophilite	75.6	74.12	42.8	27.2

As shown in Table 2, the TSR of the heat shielding materials formed by the sheet material with average aspect ratios of 23.83, 70.55, and 74.12 were all more than 40%, even more than 45%. The L-value of these heat shielding materials were all less than 30, even less than 25.
Below, different siloxane functional groups were used to prepare the heat shielding materials in Example 5 and Example 6. ISO 9050 was used to determine the TSR of the resulting heat shielding material and ASTM D1003 was used to calculate the L-value of the resulting heat shielding material. The results of comparing Example 1 and Examples 5, 6 are shown in Table 3.

EXAMPLE 5

The same process described in Example 1 was repeated, except that TEOS was replaced by MTES (Momentive; A162).

EXAMPLE 6

The same process described in Example 1 was repeated, except that TEOS was replaced by n-octyltriethoxysilane (Momentive; A137).

TABLE 3

Comparison of the resulting heat shielding materials
formed by different siloxane functional groups

	siloxane functional groups	TSR (%)	L-value

Example 1	TEOS	47.2	24.8
Example 5	MTES	41.1	26.3
Example 6	n-octyltriethoxysilane	27.2	24.8

As shown in Table 3, the TSR of the heat shielding materials formed by different siloxane functional groups were all more than 20%. The TSR of the heat shielding materials formed by TEOS and MTES was more than 40%. The L-value of these heat shielding materials formed by different siloxane functional groups were all less than 30, even less than 25.

EXAMPLE 7

1 g of the heat shielding material of Example 1 and 5 g of acrylic resin (Eternal Materials Co., Ltd., ETERAC 7132-2-M-20) were thoroughly mixed. The mixture was coated onto a metal substrate by blade coating process, and then dried at 100° C. for 10 min to form a heat shielding structure. ISO 9050 was used to determine the TSR of the resulting heat shielding structure and ASTM D1003 was used to calculate the L-value of the resulting heat shielding structure.

EXAMPLE 8

1 g of the heat shielding material of Example 1 and 1 g of dispersant (DISPARLON, 4200-10) were thoroughly mixed, and then 5 g of acrylic resin (Eternal Materials Co., Ltd., ETERAC 7132-2-M-20) was added and thoroughly mixed. The mixture was coated onto a galvanized steel by blade coating process, and then dried at 100° C. for 10 min to form a heat shielding structure. ISO 9050 was used to determine the TSR of the resulting heat shielding structure and ASTM D1003 was used to calculate the L-value of the resulting heat shielding structure.

COMPARATIVE EXAMPLE 3

1 g of commercial Carbon Black (Cabot ML) and 5 g of acrylic resin (Eternal Materials Co., Ltd., ETERAC 7132-2-M-20) were thoroughly mixed. The mixture was coated onto a galvanized steel by a blade coating process, and then dried at 100° C. for 10 min to form a heat shielding structure. ISO 9050 was used to determine the TSR of the resulting heat shielding structure and ASTM D1003 was used to calculate the L-value of the resulting heat shielding structure.
The results of the determined TSR and L-value of Example 7, Example 8, and Comparative Example 3 are shown in Table 4. The heat shielding layers of the heat shielding structures of Example 7, Example 8, and Comparative Example 3 have the same thickness.

TABLE 4

Heat shielding material	TSR (%)	L-value

Example 7	Example 1	35.1	29.3
Example 8	Example 1 + dispersant	42.6	29.8
Comparative Example 3	Commercial Carbon	<5	<10
	Black

As shown in Table 4, no matter whether the dispersant was added or not, the TSR of the heat shielding structure formed by the heat shielding material of Example 1 was more than that of the heat shielding structure formed by commercial Carbon Black. The L-values of the heat shielding structures were all less than 30. The difference was that when the heat shielding structure was formed by the heat shielding material of Example 1 without a dispersant, the TSR was 35.1%, while the heat shielding structure was formed by the heat shielding material of Example 1 with a dispersant, the TSR was improved to 42.6%. The TSR of the heat shielding structure was improved about 7.5% compared to a heat shielding structure without a dispersant.
An accelerated weathering (QUV) test was used to test the heat shielding structures of Example 7 and Example 8. It was found that the TSR of the heat shielding structure can be maintained after an QUV irradiation lasting for 1000 hr. According to the standard of ASTM G154, the service life of the above heat shielding structure can be up to 5 years.
The heat shielding material provided by the present disclosure includes the pigment layer completely and stably covering the sheet material, which assists in improving the TSR. In addition, the heat shielding structure formed from this heat shielding material has an improved total solar reflectance (TSR >40%), a low L-value (L<30), and an improved weather resistance (QUV irradiation lasting for about 1000 hr), which can be widely applied to buildings, walls, roofs, and cars.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.

Claims

What is claimed is:

1. A heat shielding material, comprising:

a sheet material; and

a pigment layer covering the sheet material, wherein the pigment layer comprises:

a crosslinking structure formed of siloxane functional groups; and

pigments dispersed in the crosslinking structure.

2. The heat shielding material as claimed in claim 1, wherein the pigment layer and the sheet material form a chemical bond through the siloxane functional groups.

3. The heat shielding material as claimed in claim 1, wherein there is an intermolecular force between the pigments and the crosslinking structure.

4. The heat shielding material as claimed in claim 1, wherein the sheet material has an average particle size of 0.1-300 μm.

5. The heat shielding material as claimed in claim 1, wherein the sheet material has an average aspect ratio of 10-100.

6. The heat shielding material as claimed in claim 1, wherein the sheet material comprises mica, synthetic mica, hygrophilite, kaolin clay, montmorillonite, silicon dioxide, sheet metal oxides, slate flake, aluminum silicate salt, or a combination thereof.

7. The heat shielding material as claimed in claim 1, wherein the siloxane functional groups are selected from compounds having a chemical formula of Si(OR)₄, wherein each R is independently H or alkyl group.

8. The heat shielding material as claimed in claim 7, wherein the siloxane functional groups are selected from tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), n-octyltriethoxysilane, or a combination thereof.

9. The heat shielding material as claimed in claim 1, wherein the pigments comprise black pigments, red pigments, blue pigments, green pigments, yellow pigments, or a combination thereof.

10. A heat shielding composition, comprising:

1 part by weight of the heat shielding material as claimed in claim 1; and

0.1-300 parts by weight of a solvent.

11. The heat shielding composition as claimed in claim 10, wherein the solvent comprises methanol, ethanol, isopropanol, n-butanol, methyl ethyl ketone, acetone, cyclohexanone, methyl tertiary-butyl ketone, diethyl ether, ethylene glycol dimethyl ether, glycol ether, ethylene glycol monoethyl ether, tetrahydrofuran (THF), propylene glycol monomethyl ether acetate (PGMEA), ethyl-2-ethoxy ethanol acetate, 3-ethoxy propionate, isoamyl acetate, ethyl acetate, butyl acetate, chloroform, pentane, n-hexane, cyclohexane, heptane, benzene, toluene, xylene, or a combination thereof.

12. The heat shielding composition as claimed in claim 10, further comprising 0.1-60 parts by weight of a resin.

13. The heat shielding composition as claimed in claim 12, wherein the resin comprises polyester resin, polyimide resin, acrylic resin, epoxy resin, silicone resin, phenoxy resin, urethane resin, urea resins, acrylonitrile butadiene styrene resin (ABS resin), polyvinyl butyral resin (PVB resin), polyether resin, fluorine-containing resin, polycarbonate resin, polystyrene resin, polyamide resin, starch, cellulose, or a combination thereof.

14. The heat shielding composition as claimed in claim 10, further comprising 0.1-3 parts by weight of a dispersant.

15. The heat shielding composition as claimed in claim 14, wherein the dispersant comprises a polymer type dispersant, wherein the polymer type dispersant comprises acrylic acid copolymer, polyamide/oxidized polyethylene copolymer mixture, polyethylene copolymer, or a combination thereof.

16. A heat shielding structure, comprising:

a substrate; and

a heat shielding layer disposed on the substrate, wherein the heat shielding layer comprises the heat shielding materials as claimed in claim 1 regularly arranged in a resin, wherein the heat shielding materials are parallel to each other and substantially parallel to a surface of the substrate,

wherein a weight ratio between the heat shielding materials and the resin is 0.02-10.

17. The heat shielding structure as claimed in claim 16, wherein the substrate comprises a rigid substrate or a flexible substrate.

18. The heat shielding structure as claimed in claim 16, wherein the resin comprises polyester resin, polyimide resin, acrylic resin, epoxy resin, silicone resin, phenoxy resin, urethane resin, urea resins, acrylonitrile butadiene styrene resin (ABS resin), polyvinyl butyral resin (PVB resin), polyether resin, fluorine-containing resin, polycarbonate resin, polystyrene resin, polyamide resin, starch, cellulose, or a combination thereof

19. The heat shielding structure as claimed in claim 16, further comprising a dispersant, and a weight ratio between the heat shielding material and the dispersant is 0.3-10.

20. The heat shielding structure as claimed in claim 19, wherein the dispersant comprises a polymer type dispersant, wherein the polymer type dispersant comprises ethylene-vinyl acetate copolymer, ethylene-vinyl acetate copolymer mixture, ethylene acrylic acid copolymer, polyamide/oxidized polyethylene copolymer mixture, polyethylene copolymer, or a combination thereof.

21. The heat shielding structure as claimed in claim 16, wherein the heat shielding structure has an L-value<30.

22. The heat shielding structure as claimed in claim 16, wherein the heat shielding structure has a total solar reflectance (TSR)>20%