Reflective granular composition

Abstract

The present disclosure relates to a reflective particulate composition comprising: a reflective pigment material comprising kaolin clay; aluminum trihydrate (ATH); and a hardening additive. The present disclosure also relates to a building material comprising the reflective particulate composition. The present disclosure also relates to a method of making the reflective particulate composition.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of priority of U.S. Provisional Application No. 63 / 415,075, filed on October 11, 2022. The entire content thereof is incorporated herein by reference. Background Art Technical Field

[0003] The present disclosure relates to a reflective granular composition and a method for its preparation.

[0004] Technical Considerations

[0005] Commercial and residential roofs are continuously exposed to external elements, which are often harsh or extreme. Even under moderate external conditions, these roofs are exposed to environmental or weather conditions that affect the roof's ability to insulate the interior of a building or residence from the effects of the environment or weather. In many parts of the world, during the summer months, roofs are continuously exposed to high heat and sunlight conditions, under which roof materials absorb solar energy and retain a high level of heat. As the roof absorbs solar energy and retains heat, the conditions inside the underlying building or residence are adversely affected, often resulting in the interior warming to uncomfortable conditions.

[0006] To remedy these conditions, buildings or residences often resort to increasing amounts of internal insulation materials or increasing the use of artificial cooling systems (e.g., HVAC equipment). However, increasing the amount of insulation material has a limited ability to reduce heat transfer, and the increased energy costs make the increased use of artificial cooling systems unsatisfactory or even prohibitively expensive.

[0007] Accordingly, there is a desire to provide a roof that is more resistant to temperature increases caused by incident solar radiation. Summary of the Invention

[0008] The present disclosure relates to a reflective granular composition comprising: a reflective pigment material comprising kaolin clay; aluminum trihydroxide (ATH); and a hardening additive.

[0009] In some non-limiting embodiments or aspects, based on the total solids of the reflective granular composition, the reflective granular composition may include at least 50 wt% kaolin clay. The reflective pigment material may include a minor pigment component selected from the group consisting of metals and transition metal oxides, alkaline earth metal sulfates, alkaline earth metal carbonates, transition metal silicates, metal silicates, minerals, and mixtures thereof. The reflective pigment material may consist of kaolin clay. Based on the total solids of the reflective granular composition, the reflective granular composition may include 5 to 40 wt% ATH. The hardening additive may include a sodium salt or other salts. Based on the total solids of the reflective granular composition, the reflective granular composition may include 1 wt% to 15 wt% sodium salt. Based on the total solids of the reflective granular composition, the reflective granular composition may include 3 wt% to 12 wt% sodium salt. The sodium salt may be selected from the group consisting of sodium silicate, sodium hydroxide, sodium carbonate, sodium chloride, sodium polyacrylate, sodium sulfate, sodium thiosulfate, sodium phosphate, and mixtures thereof, or the other salts may be selected from the group consisting of any of the foregoing salts of barium, potassium, calcium, and lithium. The reflective granular composition may include an effective amount of kaolin clay and ATH such that it exhibits a total solar reflectance of at least 70%.

[0010] The present disclosure also relates to a building material comprising the reflective granular composition described herein.

[0011] In some non-limiting embodiments or aspects, the building material may include a roofing material.

[0012] The present disclosure also relates to a method for preparing a reflective granular composition, comprising: mixing a reflective pigment material comprising kaolin clay, aluminum trihydroxide (ATH), and a hardening additive together to form a particulate mixture; forming a slurry from the particulate mixture by adding water and a binder material thereto; granulating and / or drying the slurry; and calcining the granulated and / or dried slurry to form the reflective granular composition.

[0013] In some non-limiting embodiments or aspects, the reflective pigment material may include a secondary pigment component selected from the group consisting of metals and transition metal oxides, alkaline earth metal sulfates, alkaline earth metal carbonates, transition metal silicates, metal silicates, minerals, and mixtures thereof. The reflective pigment material may consist of kaolin clay. The hardening additive may include a sodium salt or other salts. The sodium salt may be selected from the group consisting of sodium silicate, sodium hydroxide, sodium carbonate, sodium chloride, sodium polyacrylate, sodium sulfate, sodium thiosulfate, sodium phosphate, and mixtures thereof, or the other salts may be selected from the group consisting of any of the foregoing salts of barium, potassium, calcium, and lithium. Water may be added in an amount of 20 wt% to 50 wt% based on the total weight of the slurry. The binder material may be added in an amount of 1 wt% to 10 wt% based on the dry weight of the kaolin clay. The slurry is granulated. Granulation may include extruding the slurry or spraying the slurry. The method may further include comminuting the dried and granulated slurry before calcining the dried and granulated slurry. Calcination may be carried out at a temperature of 900 °C to 1500 °C.

[0014] The present disclosure also relates to the following clauses.

[0015] Clause 1: A reflective granular composition, comprising: a reflective pigment material comprising kaolin clay; aluminum trihydroxide (ATH); and a hardening additive.

[0016] Clause 2: The reflective granular composition according to Clause 1, wherein the reflective granular composition comprises at least 50 wt% kaolin clay based on the total solids of the reflective granular composition.

[0017] Clause 3: The reflective granular composition according to Clause 1 or 2, wherein the reflective pigment material includes a secondary pigment component selected from the group consisting of metals and transition metal oxides, alkaline earth metal sulfates, alkaline earth metal carbonates, transition metal silicates, metal silicates, minerals, and mixtures thereof.

[0018] Clause 4: The reflective granular composition according to any one of Clauses 1-3, wherein the reflective pigment material consists of kaolin clay.

[0019] Clause 5: The reflective granular composition according to any one of Clauses 1-4, wherein the reflective granular composition comprises 5 to 40 wt% ATH, such as 15 to 25 wt%, based on the total solids of the reflective granular composition.

[0020] Clause 6: The reflective granular composition according to any one of Clauses 1-5, wherein the hardening additive includes a sodium salt or other salts.

[0021] Clause 7: The reflective granular composition according to Clause 6, wherein the reflective granular composition comprises 1% to 15% by weight of a sodium salt based on the total solids of the reflective granular composition.

[0022] Clause 8: The reflective granular composition according to Clause 6 or 7, wherein the reflective granular composition comprises 3% to 12% by weight of a sodium salt based on the total solids of the reflective granular composition.

[0023] Clause 9: The reflective granular composition according to any one of Clauses 6 - 8, wherein the sodium salt is selected from the group consisting of sodium silicate, sodium hydroxide, sodium carbonate, sodium chloride, sodium polyacrylate, sodium sulfate, sodium thiosulfate, sodium phosphate, and mixtures thereof; or wherein the other salt is selected from the group consisting of any of the foregoing salts of barium, potassium, calcium, and lithium.

[0024] Clause 10: The reflective granular composition according to any one of Clauses 1 - 9, which comprises an effective amount of kaolin clay and ATH, thereby exhibiting a total solar reflectance of at least 70%.

[0025] Clause 11: A building material comprising the reflective granular composition according to any one of Clauses 1 - 10.

[0026] Clause 12: The building material according to Clause 11, wherein the building material comprises a roofing material.

[0027] Clause 13: A method for preparing a reflective granular composition, such as the reflective granular composition according to any one of Clauses 1 - 10, comprising: mixing a reflective pigment material comprising kaolin clay, aluminum trihydroxide (ATH), and a hardening additive together to form a particulate mixture; forming a slurry from the particulate mixture by adding water and a binder material thereto; granulating and / or drying the slurry; and calcining the granulated and / or dried slurry to form the reflective granular composition.

[0028] Clause 14: The method according to Clause 13, wherein the reflective pigment material comprises a minor pigment component selected from the group consisting of metals and transition metal oxides, alkaline earth metal sulfates, alkaline earth metal carbonates, transition metal silicates, metal silicates, minerals, and mixtures thereof.

[0029] Clause 15: The method according to Clause 13 or 14, wherein the reflective pigment material consists of kaolin clay.

[0030] Clause 16: The method according to any one of Clauses 13 - 15, wherein the hardening additive comprises a sodium salt or other salt.

[0031] Clause 17: The method according to Clause 16, wherein the sodium salt is selected from the group consisting of sodium silicate, sodium hydroxide, sodium carbonate, sodium chloride, sodium polyacrylate, sodium sulfate, sodium thiosulfate, sodium phosphate, and mixtures thereof; or wherein the other salt is selected from the group consisting of any of the foregoing salts of barium, potassium, calcium, and lithium.

[0032] Clause 18: The method according to any one of Clauses 13 - 17, wherein water is added in an amount of 20 wt% - 50 wt% based on the total weight of the slurry.

[0033] Clause 19: The method according to any one of Clauses 13 - 18, wherein a binder material is added in an amount of 1 wt% - 10 wt% based on the dry weight of the kaolin clay.

[0034] Clause 20: The method according to any one of Clauses 13 - 19, wherein granulating the slurry comprises extruding the slurry or spraying the slurry.

[0035] Clause 21: The method according to any one of Clauses 13 - 20, further comprising comminuting the dried and granulated slurry before calcining the dried and granulated slurry.

[0036] Clause 22: The method according to any one of Clauses 13 - 21, wherein calcination is carried out at a temperature of 900 °C - 1500 °C. Detailed Description

[0037] For the purposes of the following detailed description, it should be understood that the present invention may, unless otherwise expressly stated to the contrary, assume various alternative variations and step sequences. Further, except where otherwise indicated in any operating examples or otherwise noted, all numbers expressing quantities of ingredients, for example, used in the specification and claims, are to be understood as being modified in all instances by the term "about". Accordingly, unless otherwise indicated, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in accordance with the number of reported significant digits and by applying ordinary rounding techniques.

[0038] Although the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently contains some error resulting from the standard variations in their respective testing measurements.

[0039] In addition, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1 to 10" is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

[0040] In this application, the use of the singular includes the plural, and the plural encompasses the singular, unless specifically stated otherwise. In addition, in this application, the use of "or" means "and / or", unless specifically stated otherwise, even though "and / or" may be explicitly used in some instances. Further, in this application, the use of "a" or "an" means "at least one", unless specifically stated otherwise.

[0041] As used herein, the transitional term "comprising" (and other comparable terms such as "containing" and "including") is "open-ended" and open to the inclusion of unspecified materials. Although described in terms of "comprising", the terms "consisting essentially of" and "consisting of" are also within the scope of this disclosure.

[0042] As used herein, the terms "granular roofing material", "particulate roofing material" and like terms refer to solar-reflective granules or particles useful in so-called "cool roof" applications, and these terms are used interchangeably with the terms "solar-reflective granules", "solar-reflective particles", "reflective granules", "reflective particles" and like terms. In addition, although the granules and particles described herein are described in terms of their efficacy in "cool roof" applications, it should be understood that the granules and particles may have other uses and applications, and the embodiments are not limited to use in "cool roof" applications. For example, in some non-limiting embodiments, the granular roofing materials described herein may be useful on any outer surface, such as as a filler in an exterior coating, or similar applications.

[0043] A reflective granular composition comprises: a reflective pigment material comprising kaolin clay; aluminum trihydroxide (ATH); and a hardening additive. The reflective pigment material and the ATH and the hardening additive may be solid and / or particulate components.

[0044] A method of preparing a reflective granular composition includes: mixing a reflective pigment material comprising kaolin clay, aluminum trihydroxide (ATH), and a hardening additive together to form a particulate mixture; forming a slurry from the particulate mixture by adding water and a binder material thereto; granulating and / or drying the slurry; and calcining the granulated and / or dried slurry to form a reflective granular composition.

[0045] The particulate mixture of the reflective particulate composition of the present disclosure can include a reflective pigment material that includes kaolin clay, but can also include a certain amount of other reflective pigments. As used herein, the term "clay-based pigment composition" refers to a pigment composition that includes clay (such as hydrated or calcined kaolin clay) as a main component (i.e., clay is present in the pigment composition in the largest amount compared to any other component).

[0046] The reflective pigment material can include kaolin clay. The kaolin clay can account for at least 50% by weight of the reflective particulate composition, such as at least 60% by weight, at least 70% by weight, at least 80% by weight, at least 90% by weight, or 94% by weight, based on the total solids of the composition. The kaolin clay can account for 50% - 94% by weight of the reflective particulate composition, such as 50% - 80% by weight, 50% - 75% by weight, or 50% - 60% by weight, based on the total solids of the composition.

[0047] The type or source of kaolin clay used in the reflective pigment materials used in the present disclosure is not particularly limited. Non-limiting examples of kaolin clay materials include EPK kaolin available from Edgar Minerals (Edgar, FL) (e.g., having an Fe content of about 0.93 wt%, where the reported Fe content is adjusted to exclude loss on ignition (LOI) and normalized to 100% total oxide content), McNamee kaolin available from Vanderbilt Minerals, LLC (Norwalk, CT) (e.g., having an Fe content of about 0.38 wt%, where the reported Fe content is adjusted to exclude LOI and normalized to 100% total oxide content), Kingsley kaolin available from Kentucky-Tennessee Clay Company (Roswell, GA) (e.g., having an Fe content of 0.45 wt%, where the reported Fe content is adjusted to exclude LOI and normalized to 100% total oxide content), 6TILE kaolin available from Kentucky-Tennessee Clay Company (Roswell, GA) (e.g., having an Fe content of about 0.4 wt%, where the reported Fe content is adjusted to exclude LOI and normalized to 100% total oxide content), optiKasT kaolin available from Kentucky-Tennessee Clay Company (Roswell, GA) (e.g., having an Fe content of about 0.58 wt%, where the reported Fe content is adjusted to exclude LOI and normalized to 100% total oxide content), Ione Airfloated Kaolin available from Ione Minerals, Inc. (Ione, CA) (e.g., having an Fe content of about 0.7 wt%, where the reported Fe content is adjusted to exclude LOI and normalized to 100% total oxide content), kaolin-containing products available from Thiele Kaolin Company (Sandersville, GA); and kaolin-containing products available from Imerys S.A. (Paris, France). The kaolin clay may include calcined kaolin clay.

[0048] The kaolin clay in the reflective granular composition can act as a reflective pigment that is highly reflective at some wavelengths of solar radiation reaching the Earth's surface. When the reflective granular composition is disposed on the surface of an object placed under outdoor conditions, the kaolin clay can reflect at least a portion of the solar radiation incident on the object to reduce the temperature rise of the object caused by the incident solar radiation (by the object absorbing less and reflecting more solar radiation compared to the same object coated with the same composition without kaolin clay).

[0049] In some non-limiting embodiments, the reflective pigment material may further include at least one secondary pigment component (different from kaolin or ATH or hardening additives). For example, the secondary pigment component may include additional pigment materials and / or pigment additives. Some non-limiting examples of suitable secondary pigment components include metals and transition metal oxides (such as TiO2, ZnO, SnO, and various titanates), alkaline earth metal sulfates (such as BaSO4, MgSO4 (including anhydrous or hydrated forms, e.g., Epsom salt)), alkaline earth metal carbonates (such as SrCO3 and BaCO3), transition metal silicates (such as ZrSiO4), metal silicates (such as alkaline earth metal silicates and alkali metal silicates, non-limiting examples of which include Ca2SiO4, Ba2SiO4, magnesium silicate, and ZrSiO4), and minerals (such as cristobalite). For example, in some non-limiting embodiments, the secondary pigment component may include TiO2, BaSO4, ZnO, ZrSiO4, SrCO3, metal silicates (such as alkali metal silicates and / or alkaline earth metal silicates), and / or cristobalite.

[0050] The particulate mixture of the reflective particulate composition of the present disclosure may include aluminum trihydroxide (ATH). Non-limiting examples of suitable ATH that can be used include POYLFILL or POLYJET products available from Cimbar Performance Materials (Chatsworth, GA), such as POLYFILL 30, POLYFILL 110, POLYFILL 130, POLYFILL203, POLYFILL 204, POLYFILL 301, POLYFILL 302, POLYFILL 402, POLYFILL 403, POLYFILL405, POLYFILL 407, and POLYJET 502.

[0051] Based on the total solids of the reflective particulate composition, the reflective particulate composition may contain 5 to 40 wt% of ATH, such as 20 wt% to 40 wt%, 10 wt% to 30 wt%, 15 wt% to 25 wt%, or 20 wt% to 25 wt%. Based on the total solids of the reflective particulate composition, the reflective particulate composition may contain at least 5 wt% of ATH, such as at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, or at least 30 wt%. Based on the total solids of the reflective particulate composition, the reflective particulate composition may contain at most 40 wt% of ATH, such as at most 35 wt%, at most 30 wt%, at most 25 wt%, or at most 20 wt%.

[0052] The ATH in the reflective granular composition can act as an additional highly solar-reflective component in addition to kaolin clay. The ATH can be highly reflective at some wavelengths of solar radiation reaching the Earth's surface. Compared with kaolin clay, the ATH can be reflective at the same or different wavelengths of solar radiation. Compared with kaolin clay, the ATH can be particularly effective in reflecting some ultraviolet (UV) wavelengths of solar radiation. When the reflective granular composition is disposed on the surface of an object placed under outdoor conditions, the ATH can reflect at least a portion of the solar radiation incident on the object to reduce the temperature increase of the object caused by the incident solar radiation (by the object absorbing less and reflecting more solar radiation compared to the same object coated with the same composition without ATH).

[0053] Compared with the same composition except omitting kaolin clay or ATH, the reflective granular composition containing both kaolin clay and ATH can be more effective in reflecting solar radiation (e.g., measured by total solar reflectance).

[0054] The reflective granular composition can contain an effective amount of kaolin clay and ATH so as to exhibit an overall volume solar reflectance of at least 70% (also referred to herein as "total solar reflectance" (TSR) or simply "solar reflectance"), such as at least 80% or at least 85%, as measured by using a reflectometer from Surface Optics Corporation (San Diego, CA). The reflective granular composition can exhibit a TSR of 70 - 90%, 80 - 90%, 70 - 95% or 80 - 95%. For example, a 410 - Solar Visible / NIR portable reflectometer from Surface Optics Corporation (San Diego, CA) can be used, which measures the reflectance in 7 wavelength bands and uses an algorithm to calculate the TSR.

[0055] The reflective granular composition may comprise an effective amount of kaolin clay and ATH, so as to exhibit at least 20% UV reflectance (e.g., in the wavelength band of 335 - 380 nm), such as 20% to 80%. In some non-limiting embodiments, the reflective granular composition may exhibit at least 25% UV reflectance, such as 25% to 75%, 25% to 70%, or 40% to 70%, as measured by using a solar reflectometer from Surface Optics Corporation (San Diego, CA). For example, in some non-limiting embodiments, the reflective granular composition may exhibit at least 50% UV reflectance, such as 50% to 70%, as measured by using a solar reflectometer from Surface Optics Corporation (San Diego, CA).

[0056] The reflective granular composition may comprise an effective amount of kaolin clay and ATH, so as to exhibit at least 60% visible light ("VIS") reflectance (e.g., in the wavelength band of 400 - 720 nm), such as 60% to 97% or 60% to 95%, as measured by using a solar reflectometer from Surface Optics Corporation (San Diego, CA). For example, in some non-limiting embodiments, the reflective granular composition may exhibit at least 70% VIS reflectance, such as 70% to 98% or 70% to 97%, as measured by using a solar reflectometer from Surface Optics Corporation (San Diego, CA).

[0057] The reflective granular composition may comprise an effective amount of kaolin clay and ATH, so as to exhibit at least 60% infrared light ("IR") reflectance (e.g., in the wavelength band of 700 - 2500 nm), such as 60% to 98% or 60% to 97%, as measured by using a solar reflectometer from Surface Optics Corporation (San Diego, CA). For example, in some non-limiting embodiments, the particulate composition may exhibit at least 70% IR reflectance, such as 70% to 98% or 70% to 97%, as measured by using a solar reflectometer from Surface Optics Corporation (San Diego, CA).

[0058] To improve the strength of the resulting reflective granular composition, the particulate mixture may further comprise at least one hardening additive. Hardening additives suitable for use in accordance with the present disclosure may include sodium salts. Exemplary sodium salts that may form the hardening additive may include sodium silicate, sodium hydroxide, or mixtures thereof. In further exemplary embodiments, the sodium salts that may form the hardening additive may include sodium carbonate, sodium chloride, sodium polyacrylate, sodium sulfate, sodium thiosulfate, sodium phosphate, or mixtures thereof. In some non-limiting embodiments, any of the foregoing salts of barium, potassium, calcium, and lithium may also be used additionally or alternatively. Hydrated forms of any of the foregoing salts are also suitable. The foregoing types of sodium (and other) salts may be supplied in powder or particulate / crystalline form and may then be suitably incorporated into the particulate mixture.

[0059] In some non-limiting embodiments, based on the total solids of the reflective granular composition, the reflective granular composition may comprise from 1 wt% to 15 wt% of the hardening additive, such as from 1 wt% to 12 wt%, from 1 wt% to 10 wt%, from 1 wt% to 8 wt%, or from 1 wt% to 5 wt%. Based on the total solids of the reflective granular composition, the reflective granular composition may comprise from 3 wt% to 15 wt% of the hardening additive, such as from 5 wt% to 10 wt%, from 5 wt% to 15 wt%, from 8 wt% to 15 wt%, or from 10 wt% to 15 wt%. Based on the total solids of the reflective granular composition, the reflective granular composition may comprise from 1 wt% to 3 wt%, from 3 wt% to 5 wt%, from 5 wt% to 7 wt%, from 7 wt% to 10 wt%, from 10 wt% to 12 wt%, or from 12 wt% to 15 wt% of the hardening additive.

[0060] The particulate mixture may be prepared as a slurry for further processing. The slurry may include a liquid medium (such as water) and at least one binder composition. The slurry may form a substantially homogeneous mixture. As used herein, the term "substantially" is used as an approximation term rather than a degree term and is intended to account for inherent deviations and variations in the properties or values being measured, observed, or calculated. Thus, the term "substantially homogeneous" means that while the mixture may not be perfectly homogeneous, the mixture will be considered homogeneous to one of ordinary skill in the art.

[0061] In some non-limiting embodiments, the method of forming a slurry may include adding a liquid medium (such as water) to a mixture of components until a desired consistency is achieved. The desired consistency at this stage of the process may vary depending on various factors, such as whether the composition is desired to be ultimately moldable or flowable. However, in some non-limiting embodiments, the liquid medium may be added to the particulate mixture in an amount of 20 to 50 wt%, such as 30 to 40 wt%, based on the total weight of the slurry. For example, in some non-limiting embodiments where the composition is desired to be moldable, the liquid medium may be added to the particulate mixture in an amount of 20 to 40 wt%, such as 25 to 35 wt% or 25 to 30 wt%, based on the total weight of the slurry. In some non-limiting embodiments where the composition is desired to be flowable, the liquid medium may be added to the particulate mixture in an amount of 30 - 50 wt%, such as 35 to 45 wt% or 35 to 40 wt%, based on the total weight of the slurry.

[0062] In addition, to improve the consistency and adhesion of the particles within the slurry, a binder material may be added. Suitable binder materials include water-soluble polymers, such as water-soluble synthetic polymers. The water-soluble synthetic polymers may contain hydrophilic functional groups, such as ethers, alcohols, amides, and pyrrolidones. In some non-limiting embodiments or aspects, the binder material may comprise polyvinyl alcohol.

[0063] Based on the dry weight of the kaolin clay, the binder material may be added to the slurry mixture in an amount of 1 to 10 wt%, such as 3 to 8 wt%. Based on the dry weight of the kaolin clay, the binder material may be added to the slurry mixture in an amount of 1 to 8 wt%, 1 to 5 wt%, 3 to 10 wt%, or 5 to 10 wt%. Based on the dry weight of the kaolin clay, the binder material may be added to the slurry mixture in an amount of 1 to 3 wt%, 3 to 5 wt%, 5 to 8 wt%, or 8 to 10 wt%.

[0064] The slurry may then be processed into a granular form and / or dried. In some non-limiting embodiments, the method may further include extruding the slurry, or spray granulating the slurry, and drying the extruded or spray granulated product. Drying may be carried out at any suitable temperature to substantially remove the liquid medium. As described above, the term "substantially" as used herein is an approximate term, not a term of degree, and the phrase "substantially remove the liquid medium" is intended to account for the inherent deviation in the measurement, calculation, or observation of the amount of liquid medium remaining in the mixture after drying. For example, if the amount of liquid medium remaining in the mixture is either undetectable or otherwise negligible, the liquid medium is considered to be substantially removed, as would be understood by a person of ordinary skill in the art.

[0065] The temperature of the dried slurry is not particularly limited and can vary depending on the selected liquid medium. However, the temperature should be high enough to substantially remove the liquid medium, but not so high as to constitute a heat treatment or calcination process. For example, drying can be carried out at a temperature of 100°C to 800°C (such as 100°C to 700°C, 120°C to 160°C, 130°C to 150°C). Additionally, the time required to dry the wet mixture is not particularly limited and can vary depending on the consistency of the wet mixture, the liquid medium used in the wet mixture, the temperature at which drying is carried out, and the amount of the liquid medium in the wet mixture. In some non-limiting embodiments, drying is carried out for 10 minutes to 90 minutes (such as 20 minutes to 70 minutes or 30 minutes to 60 minutes).

[0066] The dried mixture can then be crushed and / or calcined (or subjected to a heat treatment). In embodiments where the dried mixture is both crushed and calcined, the dried mixture can be first crushed and then calcined, or first calcined and then crushed. In some non-limiting embodiments, using a sieve and crusher of the desired size, the dried mixture can be first crushed (before calcination) to the desired particle size. This pre-crushing can allow any fine material (or fine particles) to be reintroduced into the product feed, thereby reducing the amount of waste generated by the process. The fine particles generated during the crushing process can be recycled by reintroducing them into the production feed. However, due to their smaller particle size, the amount of the liquid medium required to achieve the desired consistency of the wet mixture can be increased. In some non-limiting embodiments, the recycled fine particles can be added to the production feed in an amount of 25 wt% or less of the feed.

[0067] As described above, according to some non-limiting embodiments of the present disclosure, the dried mixture can be calcined before or after crushing. The calcination process can be carried out at any suitable temperature and for any suitable length of time. For example, in some non-limiting embodiments, the dried mixture (before or after crushing) can be calcined (or fired) at a temperature of 800°C or 900°C to 1500°C (such as 1000°C to 1300°C, 1025°C to 1275°C, or 1050°C to 1250°C).

[0068] In some non-limiting embodiments, the resulting particles can have a density of 40 lb / ft 3 to 75 lb / ft 3 (such as 50 lb / ft 3 to 75 lb / ft 3 , 40 lb / ft 3 to 60 lb / ft 3 , 50 lb / ft 3 to 60 lb / ft 3or 45 lb / ft 3 to 60 lb / ft 3 ) bulk density. In some non - limiting embodiments, the resulting particulate composition can have a bulk density of 50 lb / ft 3 to 60 lb / ft 3 (e.g., 52 lb / ft 3 to 58 lb / ft 3 or 53 lb / ft 3 to 56 lb / ft 3 ). The relatively low bulk density of the particulate composition enables significant cost savings. For example, the lower bulk density allows less particulate (or particles) to be applied per unit area (or square), while still achieving the solar reflectance benefits (e.g., high total solar reflectance and / or UV, VIS, and / or IR reflectance).

[0069] To maintain the high solar reflectance of the particles, the compound should be applied such that the coating and / or surface treatment does not significantly reduce the reflectance of the particles. For example, many suitable coatings and / or surface treatments can be sealants or other transparent coatings that do not adversely affect the overall solar reflectance of the particles. In some non - limiting embodiments, the particles can be treated with an emulsion of silanes and siloxanes without adding solvents.

[0070] A variety of methods and processes known to those skilled in the art can be used to apply the surface treatment and / or coating to the particles. For example, in one exemplary embodiment, after the raw material is crushed, sized, and packaged according to the preferred screen size, the particles can be saturated with the treatment by adding the particulate to an aqueous solution and then immediately drying the particles at a temperature not exceeding 600°F (316°C) to remove the excess moisture. In another exemplary embodiment, after the raw material is crushed, sized, and packaged according to the preferred screen size, the particles can be post - treated by spraying an aqueous solution onto the particles and then immediately drying the particles at a temperature not exceeding 600°F (316°C) to remove the excess moisture. In yet another exemplary embodiment, after the raw material is crushed and sized according to the preferred screen size, the particles can be treated by spraying an aqueous solution onto the particles and then immediately calcining the dried particles at a temperature not exceeding 600°F (316°C) to remove the excess moisture and then packaging the particles. In still another embodiment of coating and / or treating the particle surface, after the raw material is crushed and sized according to the preferred screen size, the particles are treated by spraying an aqueous solution onto the particles and then immediately venting the particles to remove the excess moisture and then packaging the particles. The coating and / or surface treatment can be applied as - is (e.g., off - the - shelf) or from an aqueous dilution. The dilution ratio can be from 1:5 to 1:200. The dilution can be prepared from deionized water.

[0071] Reflective granular compositions (e.g., untreated or treated) can be used to form building materials. The building materials can include roofing materials or other construction materials. The building materials can be located in an outdoor environment.

[0072] Roofing materials can be formed by applying the reflective granular composition to an asphalt layer. The asphalt layer can include asphalt or modified asphalt, which is modified with at least one reinforcing material (e.g., polyester or fiberglass). Such roofing materials with the reflective granular composition applied to the asphalt layer can constitute a cool roof system.

[0073] Examples

[0074] The following examples are presented to demonstrate the general principles of the present disclosure. The present disclosure should not be considered limited to the specific examples presented. All parts and percentages in the examples are by weight unless otherwise indicated.

[0075] Examples 1 - 4

[0076] Reflective granular composition

[0077] For Example 1, kaolin slurry (containing 1000 g of dry kaolin) at a 60% slurry concentration in water from KaMin Kaolin (Macon, GA) was mixed well in a container. 200 g of a 50% concentration sodium silicate solution ( from PQ Corporation (Malvern, PA)) was added. 333 g of 60% concentration aluminum trihydrate (POLYJET 405, from Cimbar Performance Materials (Chatsworth, GA)) was added. The final concentration of the kaolin clay was adjusted to 50% by adding water. The slurry was dried overnight at 100 °C. The dried mass was calcined in a furnace at 1150 °C for 2 hours to be sintered and then cooled to ambient temperature. The sintered material was crushed and screened through a jaw crusher to form particles such that the particle size was between 8 mesh and 40 mesh. The TSR of the particles was measured using a Devices and Services Solar Spectrum Reflectometer Model SSR. As shown in Table 1, the TSR of the particles was 89.4. The composition of Example 1 contained 20 wt% ATH and 10 wt% sodium silicate.

[0078] The compositions of Examples 2 - 4 were prepared in the same manner as Example 1, but using the amounts of kaolin, ATH, and sodium silicate shown in Table 1. Table 1 shows the TSR of Examples 1 - 4. Each of the reflective granular compositions of Examples 1 - 4 showed excellent TSR.

[0079] Table 1

[0080] Example Formulation TSR 1 Kaolin, 20% ATH, 10% sodium silicate 89.40 2 Kaolin, 20% ATH, 5% sodium silicate 88.83 3 Kaolin, 40% ATH, 5% sodium silicate 90.37 4 Kaolin, 40% ATH, 10% sodium silicate 90.13

[0081] Those skilled in the art will readily understand that the present invention can be modified without departing from the concept disclosed in the foregoing specification. Accordingly, the specific embodiments described in detail herein are illustrative only and do not limit the scope of the present invention, which scope should be accorded the full breadth of the appended claims and any and all equivalents thereof.

Claims

1. A reflective granular composition, comprising: a reflective pigment material, which comprises kaolin clay; aluminum trihydroxide (ATH); and a hardening additive.

2. The reflective granular composition according to claim 1, wherein the reflective granular composition comprises at least 50% by weight of kaolin clay based on the total solids of the reflective granular composition.

3. The reflective granular composition according to claim 1, wherein the reflective pigment material comprises a minor pigment component selected from the group consisting of metals and transition metal oxides, alkaline earth metal sulfates, alkaline earth metal carbonates, transition metal silicates, metal silicates, minerals, and mixtures thereof.

4. The reflective granular composition according to claim 1, wherein the reflective pigment material consists of kaolin clay.

5. The reflective granular composition according to claim 1, wherein the reflective granular composition comprises 5 to 40% by weight of ATH based on the total solids of the reflective granular composition.

6. The reflective granular composition according to claim 1, wherein the hardening additive comprises a sodium salt or other salts.

7. The reflective granular composition according to claim 6, wherein the reflective granular composition comprises 1% to 15% by weight of sodium salt based on the total solids of the reflective granular composition.

8. The reflective granular composition according to claim 6, wherein the reflective granular composition comprises 3% to 12% by weight of sodium salt based on the total solids of the reflective granular composition.

9. The reflective granular composition according to claim 6, wherein the sodium salt is selected from the group consisting of sodium silicate, sodium hydroxide, sodium carbonate, sodium chloride, sodium polyacrylate, sodium sulfate, sodium thiosulfate, sodium phosphate, and mixtures thereof; or wherein the other salts are selected from the group consisting of any of the foregoing salts of barium, potassium, calcium, and lithium.

10. The reflective granular composition according to claim 1, which comprises an effective amount of kaolin clay and ATH, thereby exhibiting a total solar reflectance of at least 70%.

11. A building material, which comprises the reflective granular composition according to claim 1.

12. The building material according to claim 11, wherein the building material comprises a roofing material.

13. A method for manufacturing a reflective granular composition, comprising: mixing a reflective pigment material comprising kaolin clay, aluminum trihydroxide (ATH), and a hardening additive together to form a particulate mixture; forming a slurry from the particulate mixture by adding water and a binder material to the particulate mixture; granulating and / or drying the slurry; and calcining the granulated and / or dried slurry to form the reflective granular composition.

14. The method according to claim 13, wherein the reflective pigment material comprises a minor pigment component selected from the group consisting of metals and transition metal oxides, alkaline earth metal sulfates, alkaline earth metal carbonates, transition metal silicates, metal silicates, minerals, and mixtures thereof.

15. The method according to claim 13, wherein the reflective pigment material consists of kaolin clay.

16. The method according to claim 13, wherein the hardening additive comprises a sodium salt or other salts.

17. The method according to claim 16, wherein the sodium salt is selected from the group consisting of sodium silicate, sodium hydroxide, sodium carbonate, sodium chloride, sodium polyacrylate, sodium sulfate, sodium thiosulfate, sodium phosphate, and mixtures thereof; or wherein the other salts are selected from the group consisting of any of the foregoing salts of barium, potassium, calcium, and lithium.

18. The method according to claim 13, wherein the water is added in an amount of 20% to 50% by weight, based on the total weight of the slurry.

19. The method according to claim 13, wherein the binder material is added in an amount of 1% to 10% by weight, based on the dry weight of the kaolin clay.

20. The method according to claim 13, wherein granulating the slurry comprises extruding the slurry or spraying the slurry.

21. The method according to claim 13, further comprising comminuting the dried granulated slurry before calcining the dried granulated slurry.

22. The method according to claim 13, wherein the calcination is carried out at a temperature of 900 °C to 1500 °C.