Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
  • B01J13/02—Making microcapsules or microballoons
  • B01J13/06—Making microcapsules or microballoons by phase separation
  • B01J13/14—Polymerisation; cross-linking
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
  • B01J13/02—Making microcapsules or microballoons
  • B01J13/20—After-treatment of capsule walls, e.g. hardening
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
  • B01J13/02—Making microcapsules or microballoons
  • B01J13/20—After-treatment of capsule walls, e.g. hardening
  • B01J13/22—Coating
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K2800/00—Properties of cosmetic compositions or active ingredients thereof or formulation aids used therein and process related aspects
  • A61K2800/40—Chemical, physico-chemical or functional or structural properties of particular ingredients
  • A61K2800/41—Particular ingredients further characterized by their size
  • A61K2800/412—Microsized, i.e. having sizes between 0.1 and 100 microns
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2419/00—Buildings or parts thereof
  • B32B2419/06—Roofs, roof membranes
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04D—ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS
  • E04D1/00—Roof covering by making use of tiles, slates, shingles, or other small roofing elements
  • E04D2001/005—Roof covering by making use of tiles, slates, shingles, or other small roofing elements the roofing elements having a granulated surface
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04D—ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS
  • E04D7/00—Roof covering exclusively consisting of sealing masses applied in situ; Gravelling of flat roofs
  • E04D7/005—Roof covering exclusively consisting of sealing masses applied in situ; Gravelling of flat roofs characterised by loose or embedded gravel or granules as an outer protection of the roof covering

Definitions

• Conventional roofing granules consist of a core baserock of dacite, nepheline syenite, rhyolite, andesite, etc., coated with at least one layer of pigment-containing coating.
• a typical coating is composed of sodium silicate mixed with raw clay and a pigmenting oxide.
• Energy efficient shingles are designed to have improved solar reflectivity. Titania pigmented standard white granules are known, but total reflectance of these pigments is limited by absorbance of the baserock (as conventional pigment layers do not completely "hide" the underlying base), and by absorbance in the binder system by components such as the clay.
• the present disclosure describes a first plurality of granules comprising a ceramic (i.e., comprises at least one ceramic) core having an outer surface and a shell on and surrounding the core, wherein the shell comprises at least first and second concentric layers, wherein the first layer is closer to the core than the second layer, wherein the first layer comprises first ceramic particles bound together with a first inorganic binder, wherein the first inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself), wherein the second layer comprises a second inorganic binder and optionally second ceramic particles, wherein if present the second ceramic particles are bound together with the second inorganic binder, wherein the second inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself), wherein for a given granule, the first ceramic particles are present in a first weight percent with respect to the total weight of a ceramic (i.e
• the present disclosure describes a second plurality of granules comprising a ceramic core having an outer surface and a shell on and surrounding the core, wherein the shell comprises at least first and second concentric layers, wherein the first layer is closer to the core than the second layer, wherein the first layer comprises first ceramic particles bound together with a first inorganic binder, wherein the first inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself), wherein the second layer comprises a second inorganic binder and optionally second ceramic particles, wherein if present the second ceramic particles are bound together with the second inorganic binder, wherein the second inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself), wherein for a given granule, the first layer has a first volume percent porosity and the second layer of the same granule has a second volume percent poros
• the present disclosure describes a third plurality of granules comprising a ceramic core having an outer surface and a shell on and surrounding the core, wherein the shell comprises at least a first concentric, compositional gradient layer, wherein the first layer comprises first ceramic particles bound together with a first inorganic binder, wherein the first inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself), wherein the shell of each granule collectively has a volume of at least 40 (in some embodiments, greater than 45, 50, 55, 60, 65, 70, 75, 80, or even greater than 85; in some embodiments, in a range from greater than 50 to 85, or even greater than 60 to 85) volume percent, based on the total volume of the respective granule, and wherein the granules have a minimum Total Solar Reflectance (TSR) (as determined by the Total Solar Reflectance Test described in the Examples) of at least 0.7 (TSR) (as determined
• amorphous refers to material that lacks any long-range crystal structure, as determined by the X-ray diffraction technique described in the Examples;
• ceramic refers to a metal (including silicon) oxide, which may include at least one of a carbon or a nitrogen, in at least one of an amorphous, crystalline, or glass-ceramic form;
• solid ceramic core refers to a ceramic that is substantially solid (i.e., has no more than 10 percent porosity, based on the total volume of the core);
• “functional additive” refers to a material that substantially changes at least one property (e.g., durability and resistance to weathering) of a granule when present in an amount not greater than 10 percent by weight of the granule;
• glass refers to amorphous material exhibiting a glass transition temperature
• hardener refers to a material that initiates and/or enhances hardening of an aqueous silicate solution; hardening implies polycondensation of dissolved silica into three-dimensional Si-0-Si(Al, P) bond network and/or crystallization of new phases; in some embodiments, the granules comprise excess hardener;
• mineral refers to a solid inorganic material of natural occurrence
• partially crystallized refers to material containing a fraction of material characterized by long range order.
• the present disclosure describes a method of making the first and second pluralities of granules described herein, the method comprising:
• each of the ceramic cores with a first layer precursor, wherein the first layer precursor comprises a first aqueous dispersion comprising the first ceramic particles, the first alkali silicate precursor, and the first hardener precursor;
• each of the ceramic cores with a second layer precursor, wherein the second layer precursor comprises a second aqueous dispersion comprising the second ceramic particles, the second alkali silicate precursor, and the second hardener precursor; and
• the present disclosure describes a method of making the first and second pluralities of granules described herein, the method comprising:
• first and second first layer precursors wherein the first precursor comprises first alkali silicate precursor, first hardener, and first ceramic particles, and wherein the second precursor comprises second alkali silicate precursor, and second hardener, and optionally first or second ceramic particles; coating each of the ceramic cores with the first and second first layer precursors, wherein initially the first first layer precursor is applied at a higher rate than the second first layer precursor (where initially, for example, zero amount of the second first layer precursor is applied); and curing the coated aqueous dispersion to provide the plurality of granules.
• Granules described herein are useful, for example, as roofing granules.
• Advantages of some embodiments of granules described herein may include high TSR (i.e., at least 70%) with low to moderate cost (i.e., $200 to $2000 per ton), low dust (i.e., comparable to conventional roofing granules), low staining (i.e., stain test values less than 10), and good mechanical properties (i.e., tumble toughness values of at least 50).
• high TSR i.e., at least 70%
• low to moderate cost i.e., $200 to $2000 per ton
• low dust i.e., comparable to conventional roofing granules
• low staining i.e., stain test values less than 10
• good mechanical properties i.e., tumble toughness values of at least 50.
• FIGS. 1A and IB show TSR vs. coating thickness and TSR vs. coating fraction, respectively, for Example 2 samples.
• FIGS. 2A-2C show optical images of granules of Example 2 at varying stages of coating thickness.
• FIG. 2D shows optical images of granules of Illustrative Example II without a second coating layer.
• FIG. 2E shows optical images of granules of Example 2 with a second coating layer.
• a concentric layer can be contiguous or noncontiguous.
• the first ceramic particles are present in the first layer in a first weight percent with respect to the total weight of the first layer and the second ceramic particles are present in the second layer of the same granule in a second weight percent with respect to the total weight of the second layer, wherein for a given granule, the first weight percent is greater than the second weight percent.
• the first weight percent is in a range from 30 to 90, (in some embodiments, in a range from 40 to 80, 50 to 80, or even 60 to 80) weight percent with respect to the first layer
• the second weight percent is in a range from 0 to 50, (in some embodiments, in a range from 10 to 40, 10 to 30, or even 5 to 25; in some embodiments, zero) weight percent with respect to the second layer.
• the first layer has a first volume percent porosity and the second layer of the same granule has a second volume percent porosity, wherein the first volume percent porosity of the first layer is greater than the second volume percent porosity of the respective second layer.
• the first volume percent porosity is in a range from 20 to 70, (in some embodiments, in a range from 20 to 60, 25 to 50, or even 30 to 45) volume percent with respect to the first layer, and wherein for the same granule, the second volume percent porosity is in a range from 0 to 40, (in some embodiments, in a range from 0 to 30, 0 to 20, or even 0 to 10; in some embodiments, zero) volume percent with respect to the second layer.
• Porosity as described above is typically associated with voids (that are not, for example, not filled with binder) between and among ceramic particles. Such voids are typically useful for scattering and reflecting solar radiation.
• volume percent porosity as described above is measured using, mercury porosimetry, as described in the Examples.
• very fine nanoscale porosity e.g., with pore diameters less than about 50 nanometers
• very fine nanoscale porosity e.g., with pore diameters less than about 50 nanometers
• a third layer is disposed between the core and the first layer (in some embodiments, the third layer comprises a third inorganic binder and optionally third ceramic particles; in some embodiments, if present the third ceramic particles are bound together with the third inorganic binder; in some embodiments, the third inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself).
• a fourth layer is disposed between the first and second layers (in some embodiments, the fourth layer comprises a fourth inorganic binder and optionally fourth ceramic particles; in some embodiments, if present the fourth ceramic particles are bound together with the fourth inorganic binder; in some embodiments, the fourth inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself).
• a third layer is disposed between the first and second layers (in some embodiments, the third layer comprises a third inorganic binder and optionally third ceramic particles; in some embodiments, if present the third ceramic particles are bound together with the third inorganic binder; in some embodiments, the third inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself).
• a fourth layer is disposed between the core and the first layer (in some embodiments, the fourth layer comprises a fourth inorganic binder and optionally fourth ceramic particles; in some embodiments, if present the fourth ceramic particles are bound together with the fourth inorganic binder; in some embodiments, the fourth inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself).
• the first and second layers have a first and second average thickness respectively, and wherein for the same granule, the first average thickness is greater than the second average thickness.
• Average thickness is determined from an image (for example, an image from SEM, an optical microscope, or an SEM compositional map obtained using XRF) of a cross section of a granule.
• the first average thickness is at least 50 (in some embodiments, at least 75, 100, 250, 500, or even at least 1000; in some embodiments, in a range from 50 to 1000, 100 to 500, or even 150 to 250) micrometers.
• the second average thickness is at least 0.1 (in some embodiments, at least 0.5, 1, 2, 5, 10, 25, 50, 75, or even at least 100; in some embodiments, in a range from 0.1 to 100, 0.5 to 100, 0.5 to 50, 1 to 100, 1 to 50, 5 to 75, 5 to 50, or even 10 to 30) micrometers.
• the third plurality of granules within the first compositional gradient layer there is a first average concentration of the first ceramic particles for a first region comprising at least 5 volume percent of the shell at a first average distance from the core of a granule, and a second average concentration of the first ceramic particles for a second region comprising at least 5 volume percent of the shell at a second, further average distance from the core of a granule, wherein the first average concentration is greater than the second average concentration.
• the third plurality of granules within the first compositional gradient layer there is a first average volume percent porosity for a first region comprising at least 5 volume percent of the shell at a first average distance from the core of a granule, and a second average volume percent porosity for a second region comprising at least 5 volume percent of the shell at a second, further average distance from the core of a granule, wherein the first average volume percent porosity is greater than the second average volume percent porosity.
• the third plurality of granules further comprises a second layer.
• the second layer comprises a second inorganic binder and optionally second ceramic particles, wherein if present the second ceramic particles are bound together with the second inorganic binder, wherein the second inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself).
• a third layer is disposed between the core and the first layer (in some embodiments, the third layer comprises a third inorganic binder and optionally third ceramic particles; in some embodiments, if present the third ceramic particles are bound together with the third inorganic binder; in some embodiments, the third inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself)).
• a fourth layer is disposed between the first and second layers (in some embodiments, the fourth layer comprises a fourth inorganic binder and optionally fourth ceramic particles; in some embodiments, if present the fourth ceramic particles are bound together with the fourth inorganic binder; in some embodiments, the fourth inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself)).
• the ceramic cores include solid ceramic cores.
• the core has a diameter of at least 200 micrometers (in some embodiments, at least 250 micrometers, 300 micrometers, 400 micrometers, 500, micrometers, 750 micrometers, 1 mm, 1.5 mm, or even 2 mm; in some embodiments, in a range from 200 micrometers to 2 mm, 300 micrometers to 1.5 mm, 400 micrometers to 1 mm, 500 micrometers to 1 mm, 300 micrometers to 1 mm, 300 micrometers to 2 mm, or even 1 mm to 2 mm).
• the core comprises at least one of a silicate (e.g., silicate rock) (e.g., aluminosilicate (including aluminosilicate rock) and alkali aluminosilicate (including alkali aluminosilicate rock)), aluminate (including aluminate rock) (e.g., bauxite), or silica.
• a silicate e.g., silicate rock
• aluminosilicate including aluminosilicate rock
• alkali aluminosilicate rock alkali aluminosilicate rock
• aluminate including aluminate rock
• silica e.g., silica
• the core is at least one of a crystalline, a glass, or a glass-ceramic.
• Such materials can be obtained from conventional roofing granule sources known in the art. Further crystalline, glass, or glass-ceramic materials can be made using techniques known in
• the core has no more than 10, 5, 4, 3, 2, 1, or even has zero percent porosity, based on the total volume of the core.
• the shell has an average thickness of at least 50 (in some embodiments, at least 75, 100, 150, 200, 250, 300, 350, 400, 500, or even 750; in some embodiments, in a range from 50 to 750, 100 to 500, or even 200 to 500) micrometers.
• the shell of each granule collectively comprises at least 80 (in some embodiments, at least 85, 90, or even at least 95; in some embodiments, in a range from 80 to 95) percent by weight collectively of the ceramic particles, alkali silicate, and reaction product of the alkali silicate and the hardener, based on the total weight of the shell of the respective granule.
• the shell comprises a first and second concentric layers, with the first layer being closer to the core than the second layer.
• the first layer has an average thickness of at least 50 (in some embodiments, at least 75, 100, 150, 200, 250, 300, 350, 400, 500, or even 750; in some embodiments, in a range from 50 to 750, 100 to 500, or even 200 to 500) micrometers.
• the second layer has an average thickness at least 1 (in some embodiments, at least 2, 3, 4, 5, 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 500, or even 750; in some embodiments, in a range from 1 to 750, 1 to 500, 1 to 250, 1 to 100, 50 to 750, 100 to 750, 200 to 750, 50 to 500, 100 to 500, or even 200 to 500) micrometer.
• Suitable alkali silicates include cesium silicate, lithium silicate, a potassium silicate, or a sodium silicate.
• Exemplary alkali silicates are commercially available, for example, from PQ Corporation, Malvern, PA.
• the inorganic binder further comprises reaction product of amorphous aluminosilicate hardener.
• the hardener is at least one an aluminum phosphate, an aluminosilicate, a cryolite, a calcium salt (e.g., CaC3 ⁇ 4), or a calcium silicate.
• the hardener may further comprise zinc borate.
• the hardener is amorphous. Exemplary hardeners are commercially available, for example, from commercial sources such as Budenheim Inc., Budenheim, Germany, and Solvay Fluorides, LLC, Houston, TX.
• the first and second inorganic binders are the same.
• Same inorganic binder means the same alkali silicate(s) and same hardeners are present in the same ratios.
• Same alkali means the same alkali element(s).
• Same hardener means the average amount of each element that is present in an amount greater than 10 wt.% based on the total weight of the hardener, the average amount of each phase that is present in an amount greater than 10 volume percent, the density, the mean particle size, and the mean crystallite size, are each within 10% of the average value of each other for respective hardeners.
• a first hardener consists of an average of 40 wt.% Si
• a second hardener must have an average silica content in a range from 36 wt.% to 44 wt.% to be considered the same.
• the ratio of total moles of alkali ions to silicon ions, the ratio of each alkali to each additional alkali (if present), and the ratio of hardener solids to alkali silicate solids are all within 10% of each other for respective inorganic binders (i.e., a Si to alkali mole ratio of between 1.8 and 2.2 is within 10% of a ratio of 2.0).
• the first and second inorganic binders are different (i.e., not the same).
• the inorganic binder is present as at least 5 (in some embodiments, at least 10, 15, 20, 25, 30, 35, 40, or 45, or even up to 50; in some embodiments, in a range from 5 to 50, 10 to 50, or even 25 to 50) percent by weight of the shell of each granule, based on the total weight of the shell of the respective granule.
• the ceramic particles comprise at least one component with Total Solar Reflectance (as determined by the Total Solar Reflectance Test described in the Examples) of at least 0.7.
• exemplary ceramic particles include aluminum hydroxide, metal or metalloid oxide (e.g., silica (e.g., crystoballite, quartz, etc.), an aluminate (e.g., alumina, mullite, etc.), a titanate (e.g., titania), and zirconia), a silicate glass (e.g., soda-lime-silica glass, a borosilicate glass), porcelain, calcite, or marble.
• the ceramic particles comprise mineral.
• Exemplary sources of ceramic particles include Vanderbilt Minerals, LLC, Norwalk, CT; Dadco, Lausanne, Switzerland; American Talc Company, Allamoore, TX; Imerys, Inc., Cockeysville, MD; and Cristal Metals, Woodridge, IL.
• the first and second ceramic particles are the same.
• “Same ceramic particles” means the average amount of each element that is present in an amount greater than 10 wt.% based on the total weight of the ceramic particles, the average amount of each phase that is present in an amount greater than 10 volume percent, the density, the mean particle size, and the mean crystallite size, are each within 10% of the average value of each other for respective ceramic particles. For example, if first ceramic particles consist of an average of 40 wt.% Si, then second ceramic particles must have an average silica content in a range from 36 wt.% to 44 wt.% to be considered the same.
• the first and second ceramic particles are different.
• the ceramic particles of each granule comprise no greater than 10 (in some embodiments, no greater than 5, 4, 3, 2, 1, or even zero) percent by weight pure T1O2, based on the total weight of the granule. In some embodiments, the ceramic particles of each granule comprise no greater than 10 (in some embodiments, no greater than 5, 4, 3, 2, 1, or even zero) percent by weight pure AI2O3, based on the total weight of the granule.
• the ceramic particles have an average size in a range from 200 nanometers to 200 micrometers (in some embodiments, in a range from 200 nanometers to 100 micrometers, 250 nanometers to 50 micrometers, 500 nanometers to 20 micrometers, 1 micrometers to 10 micrometers, or even 2 micrometers to 20 micrometers).
• the ceramic particles have a continuous or bimodal distribution of sizes.
• the ceramic particles may have a broad distribution of particle sizes, while in others, it may have a narrow distribution of particle sizes.
• At least one of the first or second ceramic particles independently each have a longest dimension, wherein the granules each have a longest dimension, and wherein the longest dimension of each ceramic particle for a given granule is no greater than 10% (in some embodiments, no greater than 20%) of the longest dimension of said given granule.
• the granules further comprise at least one of a functional additive (e.g., rheology modifier, durability modifier, and fluxing agent), organic binder, or pigment.
• a functional additive e.g., rheology modifier, durability modifier, and fluxing agent
• organic binder e.g., kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, kaolin, ka
• Exemplary fluxing agents include borax, which is available, for example, from Rio Tinto Minerals, Boron, CA.
• Exemplary organic binders include dextrin and carboxymethylcellulose, which are available, for example, from Dow Chemical Company, Midland, MI.
• the first and second pluralities of granules described herein can be made, for example by a method comprising:
• the first layer precursor comprises a first aqueous dispersion comprising the first ceramic particles, the first alkali silicate precursor, and the first hardener precursor;
• each of the ceramic cores with a second layer precursor, wherein the second layer precursor comprises a second aqueous dispersion comprising the second ceramic particles, the second alkali silicate precursor, and the second hardener precursor; and
• curing is conducted at least in part at a temperature in a range from 40°C to 500°C, 50°C to 450°C, 50°C to 350°C, 50°C to 250°C, 50°C to 200°C, 50°C to 150°C, 50°C to 100°C, or even 50°C to 80°C.
• curing is conducted in two stages. For example, a first curing stage at least in part at a temperature in a range from 20°C to 100°C, and a second, final curing stage at least in part at a temperature in a range from 200°C to 500°C.
• the heating rate for each stage is at one or more rates in a range from 5°C/min. to 50°C/min. In some embodiments, the feeding is over a period of time in a range from 5 minutes to 500 minutes. In some embodiments, the heating is at a temperature in a range from 50°C to 200°C.
• water is present in the first and second aqueous dispersions in each independently up to 75 (in some embodiments, up to 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, or even up to 15; in some embodiments, in a range from 15 to 75, 15 to 50, or even 15 to 35) percent by weight, based on the total weight of the respective aqueous dispersion.
• coating the ceramic core with the shell comprises fluidized bed coating.
• the fluidized bed coating comprises fluidizing ceramic cores, heating the bed of fluidized cores, and continuously feeding the aqueous dispersion into the fluidized bed.
• the third plurality of granules described herein can be made, for example, by a method comprising:
• first and second first layer precursors wherein the first precursor comprises first alkali silicate precursor, first hardener, and first ceramic particles, and wherein second precursor comprises second alkali silicate precursor, and second hardener, and optionally second ceramic particles;
• each of the ceramic cores with the first and second first layer precursors, wherein initially the first first layer precursor is applied at a higher rate than the second first layer precursor (where initially, for example, zero amount of the second first layer precursor is applied);
• the curing is conducted at least in part at a temperature in a range from 40°C to 500°C, 50°C to 450°C, 50°C to 350°C, 50°C to 250 o C, 50 o C to 200 o C, 50°C to 150°C, 50°C to 100°C, or even 50°C to 80°C.
• curing is conducted in two stages. For example, a first curing stage at least in part at a temperature in a range from 20°C to 100°C, and a second, final curing stage at least in part at a temperature in a range from 200°C to 500°C.
• the heating rate for each stage is at one or more rates in a range from 5°C/min. to 50°C/min. In some embodiments, the heating is at a temperature in a range from 50°C to 200°C.
• water is present in the first and second precursors in each independently up to 75 (in some embodiments, up to 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, or even up to 15; in some embodiments, in a range from 15 to 75, 15 to 50, or even 15 to 35) percent by weight, based on the total weight of the respective precursors.
• the granules have sizes in a range from 200 micrometers to 5 millimeters (in some embodiments, in a range from 200 micrometers to 2 millimeters, 300 micrometers to 1 millimeter, 400 micrometers to 1 millimeter; 500 micrometers to 2 millimeters; or even 1 millimeters to 5 millimeters).
• the inorganic binder is amorphous. In some embodiments, the inorganic binder is partially crystallized.
• the granules have a density in a range from 0.5 g/cm 3 to 3 g/cm 3 .
• Shaped granules can be formed, for example, by using shaped cores.
• Granules described herein may be in any of a variety of shapes, including cubes, truncated cubes, pyramids, truncated pyramids, triangles, tetrahedra, spheres, hemispheres, and cones.
• a granule can have a first face and a second face separated by an average thickness.
• such granules further comprise at least one of a straight or sloping wall.
• the granules have a Tumble Toughness Value of least 70 (in some embodiments, at least 75, 80, 85, 90, 95, 96, 97, 98, or even at least 99) before immersion in water and at least 50 (in some embodiments, at least 55, 60, 65, 70, 75, 80, 85 or even at least 90) after immersion in water at 20°C ⁇ 2°C for two months.
• the granules have a Stain Value (as determined by the Stain Value Test described in the Examples) of not greater than 15 (in some embodiments, not greater than 10, 5, 4, 3, 2, 1, or even not greater than 0.5).
• the granules further comprise at least one adhesion promoter (e.g., a polysiloxane).
• the polysiloxane can contain a hydrocarbon tail for better wetting with the hydrophobic asphalt.
• a siloxane bond can form, for example, between a granule surface and the polysiloxane, via condensation reaction, leaving the hydrophobic hydrocarbon tail on the granule surface.
• the transformation of the hydrophilic surface into a hydrophobic oily surface improves wetting of the granule surface by the asphalt.
• Exemplary polysiloxanes include "SILRES BS 60" or "SILRES BS 68" from Wacker Chemical Corporation, Adrian, MI.
• the granules further comprise at least one dust suppressant (e.g., an acrylic polymer comprising a quaternary ammonium moiety and a nonionic monomer).
• dust suppressant is believed to suppress dust through ionic interaction of the positively charged quaternary ammonium moiety and negatively charged dust particles.
• the quaternary ammonium moiety may also form, for example, an ionic bond with natural mineral.
• it may ionically bond with ionic species in asphalt, particularly polyphosphoric acid (PPA) added asphalt.
• PPA polyphosphoric acid
• a dust suppression coating composition comprising a quaternary ammonium compound as described herein may also serve as an adhesion promoter.
• the dust suppression coating polymer comprises water-based polymers, such as a polyacrylate (e.g., an acrylic emulsion polymer).
• the coating polymer is a polymer such as described in PCT Pat. Pub. Docs. WO2015157615 Al, and WO2015157612 Al, published October 15, 2015, the disclosures of which are incorporated herein by reference.
• Granules described herein are useful, for example, as roofing granules.
• granules described herein can be used to make roofing material (e.g., a shingle) comprising a substrate and the granules thereon.
• the roofing material has a Total Solar Reflectance (TSR) (as determined by the Total Solar Reflectance Test described in the Examples) of at least 60 (in some embodiments, at least 63, 65, or even at least 70) %.
• TSR Total Solar Reflectance
• Advantages of embodiments of granules described herein may include high TSR (i.e., at least 70%) with low to moderate cost (i.e., $200 to $2000 per ton), low dust (i.e., comparable to conventional roofing granules), low staining (i.e., stain test values of less than 10), and good mechanical properties (i.e., tumble toughness values of at least 50).
• high TSR i.e., at least 70%
• low to moderate cost i.e., $200 to $2000 per ton
• low dust i.e., comparable to conventional roofing granules
• low staining i.e., stain test values of less than 10
• good mechanical properties i.e., tumble toughness values of at least 50.
• a plurality of granules comprising a ceramic core having an outer surface and a shell on and surrounding the core, wherein the shell comprises at least first and second concentric layers, wherein the first layer is closer to the core than the second layer, wherein the first layer comprises first ceramic particles bound together with a first inorganic binder, wherein the first inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself), wherein the second layer comprises a second inorganic binder and optionally second ceramic particles, wherein if present the second ceramic particles are bound together with the second inorganic binder, wherein the second inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself), wherein for a given granule, the first ceramic particles are present in a first weight percent with respect to the total weight of the first layer and the second ceramic particles are present in the second layer of the same granule in
• the first weight percent is in a range from 30 to 90, (in some embodiments, in a range from 40 to 80, 50 to 80, or even 60 to 80) weight percent with respect to the first layer
• the second weight percent is in a range from 0 to 50, (in some embodiments, in a range from 10 to 40, 10 to 30, or even 5 to 25; in some embodiment, zero) weight percent with respect to the second layer.
• the first volume percent porosity is in a range from 20 to 70, (in some embodiments, in a range from 20 to 60, 25 to 50, or even 30 to 45) volume percent with respect to the first layer, and wherein for the same granule, the second volume percent porosity is in a range from 0 to 40, (in some embodiments, in a range from 0 to 30, 0 to 20, or even 0 to 10; in some embodiments, zero) volume percent with respect to the second layer.
• a third layer is disposed between the core and the first layer (in some embodiments, the third layer comprises a third inorganic binder and optionally third ceramic particles; in some embodiments, if present the third ceramic particles are bound together with the third inorganic binder; in some embodiments, the third inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself)). 7A.
• a fourth layer is disposed between the first and second layers
• the fourth layer comprises a fourth inorganic binder and optionally fourth ceramic particles; in some embodiments, if present the fourth ceramic particles are bound together with the fourth inorganic binder; in some embodiments, the fourth inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself)).
• a third layer is disposed between the first and second layers (in some embodiments, the third layer comprises a third inorganic binder and optionally third ceramic particles; in some embodiments, if present the third ceramic particles are bound together with the third inorganic binder; in some embodiments, the third inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself).
• a fourth layer is disposed between the core and the first layer
• the fourth layer comprises a fourth inorganic binder and optionally fourth ceramic particles; in some embodiments, if present the fourth ceramic particles are bound together with the fourth inorganic binder; in some embodiments, the fourth inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself)).
• the plurality of granules of Exemplary Embodiment 10A, wherein, the first average thickness is at least 50 (in some embodiments, at least 75, 100, 250, 500, or even at least 1000; in some embodiments, in a range from 50 to 1000, 100 to 500, or even 150 to 250) micrometers.
• the plurality of granules of either Exemplary Embodiment 9A or 10A, wherein, the second average thickness is at least 0.1 (in some embodiments, at least 0.5, 1, 2, 5, 10, 25, 50, 75, or even at least 100; in some embodiments, in a range from 0.1 to 100, 0.5 to 100, 0.5 to 50, 1 to 100, 1 to 50, 5 to 75, 5 to 50, or even 10 to 30) micrometers.
• the core comprises at least one of a silicate (e.g., silicate rock) (e.g., aluminosilicate (including aluminosilicate rock) and alkali aluminosilicate (including alkali aluminosilicate rock)), aluminate (including aluminate rock) (e.g., bauxite), or silica.
• a silicate e.g., silicate rock
• aluminosilicate including aluminosilicate rock
• alkali aluminosilicate including alkali aluminosilicate rock
• aluminate including aluminate rock
• silica silica
• the shell has an average thickness of at least 50 (in some embodiments, at least 75, 100, 150, 200, 250, 300, 350, 400, 500, or even 750; in some embodiments, in a range from 50 to 750, 100 to 500, or even 200 to 500) micrometers.
• each granule comprises at least 80 (in some embodiments, at least 85, 90, or even at least 95; in some embodiments, in a range from 80 to 95) percent by weight collectively of the ceramic particles, alkali silicate, and reaction product of the alkali silicate and the hardener, based on the total weight of the shell of the respective granule.
• the at least one of the first or second ceramic particles independently have an average size in a range from 200 nanometers to 200 micrometers (in some embodiments, in a range from 200 nanometers to 100 micrometers, 250 nanometers to 50 micrometers, 500 nanometers to 20 micrometers, 1 micrometers to 10 micrometers, or even 2 micrometers to 20 micrometers).
• the at least one of the first or second hardener is at least one of an aluminum phosphate, an aluminosilicate, a cryolite, a calcium salt (e.g., CaCh), or a calcium silicate.
• Such exemplary ceramic particles include aluminum hydroxide, metal or metalloid oxide (e.g., silica (e.g., crystoballite, quartz, etc.), an aluminate (e.g., alumina, mullite, etc.), a titanate (e.g., titania), and zirconia), a silicate glass (e.g., soda-lime -silica glass, a borosilicate glass), porcelain, calcite, or marble.
• silica e.g., crystoballite, quartz, etc.
• an aluminate e.g., alumina, mullite, etc.
• a titanate e.g., titania
• zirconia zirconia
• silicate glass e.g., soda-lime -silica glass, a borosilicate glass
• porcelain calcite, or marble.
• 36A The plurality of granules of any preceding A Exemplary Embodiment, wherein the granules are in at least one of the following shapes: cubes, truncated cubes, pyramids, truncated pyramids, triangles, tetrahedras, spheres, hemispheres, or cones.
• 37A The plurality of granules of any preceding A Exemplary Embodiment, wherein each granule has a first face and a second face separated by a thickness.
• a roofing material (e.g., a shingle) comprising the plurality of granules of any preceding A Exemplary Embodiment.
• TSR Total Solar Reflectance
• a method of making the plurality of granules of any preceding A Exemplary Embodiment, the method comprising: providing a plurality of ceramic cores;
• each of the ceramic cores with a first layer precursor, wherein the first layer precursor comprises a first aqueous dispersion comprising the first ceramic particles, the first alkali silicate precursor, and the first hardener precursor;
• each of the ceramic cores with a second layer precursor, wherein the second layer precursor comprises a second aqueous dispersion comprising the second ceramic particles, the second alkali silicate precursor, and the second hardener precursor; and
• 3C The method of either Exemplary Embodiment 1C or 2C, wherein the curing is conducted at least in part at a temperature in a range from 40°C to 500°C, 50°C to 450°C, 50°C to 350°C, 50°C to 250°C, 50°C to 200°C, 50°C to 150°C, 50°C to 100°C, or even 50°C to 80°C.
• curing is conducted in two stages. For example, a first curing stage at least in part at a temperature in a range from 20°C to 100°C, and a second, final curing stage at least in part at a temperature in a range from 200°C to 500°C.
• the heating rate for each stage is at one or more rates in a range from 5°C/min. to 50°C/min.
• a plurality of granules comprising a ceramic core having an outer surface and a shell on and surrounding the core, wherein the shell comprises at least first and second concentric layers, wherein the first layer is closer to the core than the second layer, wherein the first layer comprises first ceramic particles bound together with a first inorganic binder, wherein the first inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself), wherein the second layer comprises a second inorganic binder and optionally second ceramic particles, wherein if present the second ceramic particles are bound together with the second inorganic binder, wherein the second inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself), wherein for a given granule, the first layer
• the plurality of granules of Exemplary Embodiment ID wherein for a given granule, the first volume percent porosity is in a range from 20 to 70, (in some embodiments, in a range from 20 to 60, 25 to 50, or even 30 to 45) volume percent with respect to the first layer, and wherein for the same granule, the second volume percent porosity is in a range from 0 to 40, (in some embodiments, in a range from 0 to 30, 0 to 20, or even 0 to 10; in some embodiments, zero) volume percent with respect to the second layer.
• the first weight percent is in a range from 30 to 90, (in some embodiments, in a range from 40 to 80, 50 to 80, or even 60 to 80) weight percent with respect to the first layer
• the second weight percent is in a range from 0 to 50, (in some embodiments, in a range from 10 to 40, 10 to 30, or even 5 to 25; in some embodiment, zero) weight percent with respect to the second layer. 5D.
• a third layer is disposed between the core and the first layer (in some embodiments, the third layer comprises a third inorganic binder and optionally third ceramic particles; in some embodiments, if present the third ceramic particles are bound together with the third inorganic binder; in some embodiments, the third inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself)).
• a fourth layer is disposed between the first and second layers (in some embodiments, the fourth layer comprises a fourth inorganic binder and optionally fourth ceramic particles; in some embodiments, if present the fourth ceramic particles are bound together with the fourth inorganic binder; in some embodiments, the fourth inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself).
• a third layer is disposed between the first and second layers (in some embodiments, the third layer comprises a third inorganic binder and optionally third ceramic particles; in some embodiments, if present the third ceramic particles are bound together with the third inorganic binder; in some embodiments, the third inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself)).
• a fourth layer is disposed between the core and the first layer
• the fourth layer comprises a fourth inorganic binder and optionally fourth ceramic particles; in some embodiments, if present the fourth ceramic particles are bound together with the fourth inorganic binder; in some embodiments, the fourth inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself)).
• 1 ID The plurality of granules of Exemplary Embodiment 10D, wherein, the first average thickness is at least 50 (in some embodiments, at least 75, 100, 250, 500, or even at least 1000; in some embodiments, in a range from 50 to 1000, 100 to 500, or even 150 to 250) micrometers. 12D.
• the plurality of granules of any preceding D Exemplary Embodiment, wherein the ceramic cores include solid ceramic cores.
• the core has a diameter of at least 200 micrometers (in some embodiments, at least 250 micrometers, 300 micrometers, 400 micrometers, 500 micrometers, 750 micrometers, 1 mm, 1.5 mm, or even 2 mm; in some embodiments, in a range from 200 micrometers to 2 mm, 300 micrometers to 1.5 mm, 400 micrometers to
• the core comprises at least one of a silicate (e.g., silicate rock) (e.g., aluminosilicate (including aluminosilicate rock) and alkali aluminosilicate (including alkali aluminosilicate rock)), aluminate (including aluminate rock) (e.g., bauxite), or silica.
• a silicate e.g., silicate rock
• aluminosilicate including aluminosilicate rock
• alkali aluminosilicate including alkali aluminosilicate rock
• aluminate including aluminate rock
• silica silica
• the shell has an average thickness of at least 50 (in some embodiments, at least 75, 100, 150, 200, 250, 300, 350, 400, 500, or even 750; in some embodiments, in a range from 50 to 750, 100 to 500, or even 200 to 500) micrometers.
• the plurality of granules of any preceding D Exemplary Embodiment wherein at least one of the first or second ceramic particles independently each have a longest dimension, wherein the granules each have a longest dimension, and wherein the longest dimension of each ceramic particle for a given granule is no greater than 10% (in some embodiments, no greater than 20%) of the longest dimension of said given granule.
• 26D The plurality of granules of any preceding D Exemplary Embodiment, wherein at least one of the first or second ceramic particles have a bimodal distribution of sizes.
• 27D The plurality of granules of any preceding D Exemplary Embodiment, wherein at least one of the first or second inorganic binders is amorphous.
• the at least one of the first or second hardener is at least one of an aluminum phosphate, an aluminosilicate, a cryolite, a calcium salt (e.g., CaCh), or a calcium silicate.
• Such exemplary ceramic particles include aluminum hydroxide, metal or metalloid oxide (e.g., silica (e.g., crystoballite, quartz, etc.), an aluminate (e.g., alumina, mullite, etc.), a titanate (e.g., titania), and zirconia), a silicate glass (e.g., soda-lime -silica glass, a borosilicate glass), porcelain, calcite, or marble.
• silica e.g., crystoballite, quartz, etc.
• an aluminate e.g., alumina, mullite, etc.
• a titanate e.g., titania
• zirconia zirconia
• silicate glass e.g., soda-lime -silica glass, a borosilicate glass
• porcelain calcite, or marble.
• 35D The plurality of granules of any preceding D Exemplary Embodiment, wherein each respective granule has a density in a range from 0.5 g/cm 3 to 3 g/cm 3 .
• 36D The plurality of granules of any preceding D Exemplary Embodiment, wherein the granules are in at least one of the following shapes: cubes, truncated cubes, pyramids, truncated pyramids, triangles, tetrahedras, spheres, hemispheres, or cones.
• 37D The plurality of granules of any preceding D Exemplary Embodiment, wherein each granule has a first face and a second face separated by a thickness.
• 39D The plurality of granules of any preceding D Exemplary Embodiment, wherein the granules have a Stain Value not greater than 15 (in some embodiments, not greater than 10, 5, 4, 3, 2, 1, or even not greater than 0.5). 40D. The plurality of granules of any preceding D Exemplary Embodiment, further comprising at least one adhesion promoter.
• 44D The plurality of granules of any preceding D Exemplary Embodiment, wherein the second ceramic particles are present and wherein the first and second ceramic particles are the same.
• 45D The plurality of granules of any of Exemplary Embodiments ID to 43D, wherein the second ceramic particles are present and wherein the first and second ceramic particles are different.
• a roofing material e.g., a shingle
• a roofing material of Exemplary Embodiment IE having a Total Solar Reflectance (TSR) (as determined by the Total Solar Reflectance Test described in the Examples) of at least 60 (in some embodiments, at least 63, 65, or or even at least 70) %.
• TSR Total Solar Reflectance
• each of the ceramic cores with a first layer precursor, wherein the first layer precursor comprises a first aqueous dispersion comprising the first ceramic particles, the first alkali silicate precursor, and the first hardener precursor;
• each of the ceramic cores with a second layer precursor, wherein the second layer precursor comprises a second aqueous dispersion comprising the second alkali silicate precursor, the second hardener precursor, and optionally the second ceramic particles; and
• 3F The method of either Exemplary Embodiment IF or 2F, wherein the curing is conducted at least in part at a temperature in a range from 40°C to 500°C, 50°C to 450°C, 50°C to 350°C, 50°C to 250°C, 50°C to 200°C, 50°C to 150°C, 50°C to 100°C, or even 50°C to 80°C.
• curing is conducted in two stages. For example, a first curing stage at least in part at a temperature in a range from 20°C to 100°C, and a second, final curing stage at least in part at a temperature in a range from 200°C to 500°C.
• the heating rate for each stage is at one or more rates in a range from 5°C/min. to 50°C/min. 4F.
• the method of any preceding F Exemplary Embodiment, wherein water is present in the first and second aqueous dispersions are each independently up to 75 (in some embodiments, up to 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, or even up to 15; in some embodiments, in a range from 15 to 75, 15 to 50, or even 15 to 35) percent by weight, based on the total weight of the respective aqueous dispersion. 5F.
• the method of any preceding F Exemplary Embodiment, wherein coating the ceramic core with the shell comprises fluidized bed coating. 6F.
• the fluidized bed coating comprises fluidizing ceramic cores, heating the bed of fluidized cores, and continuously feeding the aqueous dispersion into the fluidized bed. 7F.
• a plurality of granules comprising a ceramic core having an outer surface and a shell on and surrounding the core, wherein the shell comprises at least a first concentric, compositional gradient layer, wherein the first layer comprises first ceramic particles bound together with a first inorganic binder, wherein the first inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself), wherein the shell of each granule has a volume of at least 40 (in some embodiments, greater than 45, 50, 55, 60, 65, 70, 75, 80, or even greater than 85; in some embodiments, in a range from greater than 50 to 85, or even greater than 60 to 85) volume percent, based on the total volume of the respective granule, and wherein the granules have a minimum Total Solar Reflectance (TSR) (as determined by the Total Solar Reflectance Test described in the Examples) of at least 0.7 (in some embodiments, of at least 0.75, or even
• the second layer comprises a second inorganic binder and optionally second ceramic particles, wherein if present the second ceramic particles are bound together with the second inorganic binder, wherein the second inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself).
• a third layer is disposed between the core and the first layer (in some embodiments, the third layer comprises a third inorganic binder and optionally third ceramic particles; in some embodiments, if present the third ceramic particles are bound together with the third inorganic binder; in some embodiments, the third inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself)).
• a fourth layer is disposed between the first and second layers (in some embodiments, the fourth layer comprises a fourth inorganic binder and optionally fourth ceramic particles; in some embodiments, if present the fourth ceramic particles are bound together with the fourth inorganic binder; in some embodiments, the fourth inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself)).
• the fourth inorganic binder comprises reaction product of at least alkali silicate and hardener (in some embodiments further comprising alkali silicate itself)).
• the first layer has an average thickness at least 50 (in some embodiments, at least 75, 100, 250, 500, or even at least 1000; in some embodiments, in a range from 50 to 1000, 100 to 500, or even 150 to 250) micrometers.
• the second layer has an average thickness that is less than the average thickness of the first layer.
• the second average thickness is at least 0.1 (in some embodiments, at least 0.5, 1, 2, 5, 10, 25, 50, 75, or even at least 100; in some embodiments, in a range from 0.1 to 100, 0.5 to 100, 0.5 to 50, 1 to 100, 1 to 50, 5 to 75, 5 to 50, or even 10 to 30) micrometers.
• 9G The plurality of granules of any preceding G Exemplary Embodiment, wherein the core is at least one of a crystalline, glass, or a glass-ceramic.
• the core comprises at least one of a silicate (e.g., silicate rock) (e.g., aluminosilicate (including aluminosilicate rock) and alkali aluminosilicate (including alkali aluminosilicate rock)), aluminate (including aluminate rock) (e.g., bauxite), or silica.
• a silicate e.g., silicate rock
• aluminosilicate including aluminosilicate rock
• alkali aluminosilicate including alkali aluminosilicate rock
• aluminate including aluminate rock
• silica silica
• 11G The plurality of granules of any preceding G Exemplary Embodiment, wherein the shell has an average thickness of at least 50 (in some embodiments, at least 75, 100, 150, 200, 250, 300, 350, 400, 500, or even 750; in some embodiments, in a range from 50 to 750, 100 to 500, or even 200 to 500) micrometers.
• each granule collectively comprises at least 80 (in some embodiments, at least 85, 90, or even at least 95; in some embodiments, in a range from 80 to 95) percent by weight collectively of the ceramic particles, alkali silicate, and reaction product of the alkali silicate and the hardener, based on the total weight of the shell of the respective granule.
• the first ceramic particles each have a longest dimension, wherein the granules each have a longest dimension, and wherein the longest dimension of each first ceramic particle for a given granule is no greater than 10% (in some embodiments, no greater than 20%) of the diameter of said given granule.
• the second ceramic particles each have a longest dimension, wherein the granules each have a longest dimension, and wherein the longest dimension of each second ceramic particle for a given granule is no greater than 10% (in some embodiments, no greater than 20%) of the longest dimension of said given granule.
• the plurality of granules of any preceding G Exemplary Embodiment, wherein the first ceramic particles of each granule comprise no greater than 10 (in some embodiments, no greater than 5, 4, 3, 2, 1, or even zero) percent by weight T1O2, based on the total weight of the granule.
• the second ceramic particles of each granule comprise no greater than 10 (in some embodiments, no greater than 5, 4, 3, 2, 1, or even zero) percent by weight T1O 2 , based on the total weight of the granule. 15G.
• the plurality of granules of any preceding G Exemplary Embodiment wherein the first ceramic particles of each granule comprise no greater than 10 (in some embodiments, no greater than 5, 4, 3, 2, 1, or even zero) percent by weight pure AI 2 O3, based on the total weight of the granule.
• the second ceramic particles of each granule comprise no greater than 10 (in some embodiments, no greater than 5, 4, 3, 2, 1, or even zero) percent by weight pure AI 2 O3, based on the total weight of the granule. 16G.
• the second inorganic binder is present as at least 5 (in some embodiments, at least 10, 15, 20, 25, 30, 35, 40, or 45, or even up to 50; in some embodiments, in a range from 5 to 50, 10 to 50, or even 25 to 50) percent by weight of the shell of each granule, based on the total weight of the shell of the respective granule.
• the second ceramic particles have an average size in a range from 200 nanometers to 200 micrometers (in some embodiments, in a range from 200 nanometers to 100 micrometers, 250 nanometers to 50 micrometers, 500 nanometers to 20 micrometers, 1 micrometers to 10 micrometers, or even 2 micrometers to 20 micrometers).
• the first or second alkali silicates is at least one of a cesium silicate, lithium silicate, a potassium silicate, or a sodium silicate.
• the second inorganic binder is at least one of a cesium silicate, lithium silicate, a potassium silicate, or a sodium silicate.
• the first or second hardener is at least one of an aluminum phosphate, an aluminosilicate, a cryolite, a calcium salt (e.g., CaCh), or a calcium silicate.
• the second hardener is at least one of an aluminum phosphate, an aluminosilicate, a cryolite, a calcium salt (e.g., CaCh), or a calcium silicate.
• Such exemplary ceramic particles include aluminum hydroxide, metal or metalloid oxide (e.g., silica (e.g., crystoballite, quartz, etc.), an aluminate (e.g., alumina, mullite, etc.), a titanate (e.g., titania), and zirconia), a silicate glass (e.g., soda-lime -silica glass, a borosilicate glass), porcelain, calcite, or marble.
• silica e.g., crystoballite, quartz, etc.
• an aluminate e.g., alumina, mullite, etc.
• a titanate e.g., titania
• zirconia zirconia
• silicate glass e.g., soda-lime -silica glass, a borosilicate glass
• porcelain calcite, or marble.
• the first ceramic particles comprise mineral.
• the second ceramic particles comprise mineral.
• the granules further comprise at least one of a functional additive (e.g., rheology modifier (e.g., surfactant), durability modifier (e.g., nanosilica), and fluxing agent), organic binder, or pigment.
• a functional additive e.g., rheology modifier (e.g., surfactant), durability modifier (e.g., nanosilica), and fluxing agent
• each respective granule has a density in a range from 0.5 g/cm 3 to 3 g/cm 3 . 30G.
• the plurality of granules of any preceding G Exemplary Embodiment, wherein the granules are in at least one of the following shapes: cubes, truncated cubes, pyramids, truncated pyramids, triangles, tetrahedras, spheres, hemispheres, or cones.
• 32G The plurality of granules of Exemplary Embodiment 30G, wherein at least some granules further comprise at least one of a straight or sloping wall.
• 33G The plurality of granules of any preceding G Exemplary Embodiment, wherein the granules have a Stain Value not greater than 15 (in some embodiments, not greater than 10, 5, 4, 3, 2, 1, or even not greater than 0.5).
• 35G The plurality of granules of Exemplary Embodiment 34G, wherein the adhesion promotor comprises a polysiloxane.
• 36G The plurality of granules of any preceding G Exemplary Embodiment, further comprising at least one dust suppressant.
• a roofing material e.g., a shingle
• a roofing material comprising the plurality of granules of any preceding G Exemplary Embodiment.
• TSR Total Solar Reflectance
• II. A method of making the plurality of granules of any preceding G Exemplary Embodiment, the method comprising:
• first and second first layer precursors wherein the first precursor comprises first alkali silicate precursor, first hardener, and first ceramic particles, and wherein second precursor comprises second alkali silicate precursor, and second hardener, and optionally first or second ceramic particles; coating each of the ceramic cores with the first and second first layer precursors, wherein initially the first layer precursor is applied at a higher rate than the second first layer precursor (where initially, for example, zero amount of the second first layer precursor is applied); and
• curing is conducted at least in part at a temperature in a range from 40°C to 500°C, 50°C to 450°C, 50°C to 350°C, 50°C to 250°C, 50°C to 200°C, 50°C to 150°C, 50°C to 100°C, or even 50°C to 80°C.
• curing is conducted in two stages. For example, a first curing stage at least in part at a temperature in a range from 20°C to 100°C, and a second, final curing stage at least in part at a temperature in a range from 200°C to 500°C.
• the heating rate for each stage is at one or more rates in a range from 5°C/min. to 50°C/min.
• coating the ceramic core with the shell comprises fluidized bed coating.
• the fluidized bed coating comprises fluidizing ceramic cores, heating the bed of fluidized cores, and continuously feeding the aqueous dispersions into the fluidized bed.
• Examples 1-3 and Illustrative Examples I and II were prepared by applying a "base" coating layer on core mineral granules as follows: Grade #11 uncoated naturally occurring dacite mineral (obtained from 3M Company, St. Paul, MN) was screened to 14 or 18 grade using -14 mesh or -18 mesh U.S. sieve (see Table 1 (below) for grade size distributions), suspended in fluidized bed coater (obtained under the trade designation "GLATT GPCG-1" from Glatt, Weimar, Germany), and equilibrated at targeted temperature (25-30 ° C) prior to application of coating slurry.
• Grade #11 uncoated naturally occurring dacite mineral obtained from 3M Company, St. Paul, MN
• -14 mesh or -18 mesh U.S. sieve see Table 1 (below) for grade size distributions
• suspended in fluidized bed coater obtained under the trade designation "GLATT GPCG-1" from Glatt, Weimar, Germany
• Reactive metakaolin anhydrous amorphous Pigment Company, Sandersville,
• PSA57180 PSA57180 POLYMER
• PSA57180 POLYMER from POLYMER Acrylate polymer and water 3M Company, St. Paul, MN
• the slurry spray rate was kept as high as possible without accumulating moisture in the product bed.
• Product temperature was kept in the range 26-32°C
• the atomizing pressure was 20- 35 psi (138-241 kPa)
• the fluidizing air was 400-600 fpm (122-183 meters per minute)
• the spray rate was 40-75 g/min.
• the fluidizing air was generally kept as low as possible while maintaining fluidized bed motion. Typical settings of batch fluid bed coater that was used as outlined below.
• the coating process to form base coat of final thickness took about 1-2 hour.
• the final thickness i.e., the "optimum optical thickness" was determined by plotting total solar reflectance (TSR) versus amount of coating (thickness in micrometers or amount of coating expressed as estimated weight fraction of coated granule). Once the graph of TSR versus amount of coating applied reaches a plateau, further increase in coating thickness was inexpedient for that combination of core granules and coating slurry composition.
• FIGS. 1A and IB show TSR vs. coating thickness and TSR vs. coating fraction, respectively, for Example 2.
• Final thickness of the first coating layer of Examples 1-3 and Illustrative Example I and II ranged from 200 to 400 micrometers, which corresponded to about 50-85 wt.% of the whole granule construction.
• FIGS. 2A-C show optical images of bright white core-shell granules of Example 2 (base coating thicknesses corresponding to a 0.2-0.3 coating fraction) at various stages of the coating process.
• a second layer was designed as a final thin coating (about 10-20 micrometers) which was applied on top of the base coating layer to decrease total surface area of the granule by eliminating open porosity and dust.
• Seal coat was applied in fluid bed coater as final coating with the following parameters of the run: product temperature was kept in the range 30-35°C, the atomizing pressure was 25 psi (172 kPa), the fluidizing air was 12-13 fpm (about 3.8 meters per minute), and the spray rate was 6-7 g/min.
• Illustrative Example I represented granules of Example 1 on which no second coating layer was applied.
• Illustrative Example II represented granules of Examples 2 and 3 on which no second coating layer was applied.
• FIGS. 2D and 2E show optical images of Illustrative Example II and Example 2 respectively showing the impact of adding a second coating layer per Example 2.
• the coated and cured granules were post treated with an adhesion promoting solution.
• the adhesion promoting solution (prepared using formula according to Table 3 above) was applied to the surfaces of the granules by mixing 1000 grams of granules with 36.9 grams of the adhesion promoting solution in a 1 -gallon (3.79 L) can on a paint shaker for 5 minutes. Treated granules were tested using the "Water Repellency Test.”
• Illustrative Examples III and IV are examples of formulas that could be used as a first and second layer, respectively, on the core. These examples were prepared by mixing the ingredients according to the formula in Table 3 (above), then drying in a pan at 80°C in oven, followed by crushing and screening to granule sizes of 425-2000 micrometers. Screened fraction of the granules was placed into a batch oven, where they were heated with heating rate of 2°C/min. up to 450°C and subsequently cured at that temperature for 3 hours. These samples were used to test porosity of materials. The results of all tests are summarized in Table 3, above. [0079] Foreseeable modifications and alterations of this disclosure will be apparent to those skilled in the art without departing from the scope and spirit of this invention. This invention should not be restricted to the embodiments that are set forth in this application for illustrative purposes.

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• 2018
  • 2018-06-13 CN CN201880040152.0A patent/CN110785225A/zh active Pending
  • 2018-06-13 WO PCT/IB2018/054323 patent/WO2018234943A1/en not_active Ceased
  • 2018-06-13 US US16/620,141 patent/US20200147577A1/en not_active Abandoned
  • 2018-06-13 JP JP2019569946A patent/JP2020524074A/ja active Pending
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