Title:
GYPSUM PANEL CONTAINING AMMONIUM-EXCHANGED VERMICULITE AND METHODS
Document Type and Number:
WIPO Patent Application WO/2023/154662
Kind Code:
A4
Abstract:
This disclosure provides products useful as construction materials and containing set gypsum and ammonium-exchanged vermiculite, including a gypsum panel having a gypsum core comprising set gypsum and ammonium-exchanged vermiculite and characterized by decreased heat shrinkage and increased resistance to fire damage in comparison to the gypsum panel that comprises vermiculite that has not been ammonium-exchanged. The disclosure further relates to methods for producing the gypsum panel and constructing building assemblies with the gypsum panels, including walls and ceilings.
Inventors:
LI QINGHUA (US)
HEMPHILL MARK (US)
HEMPHILL MARK (US)
Application Number:
PCT/US2023/061945
Publication Date:
October 05, 2023
Filing Date:
February 03, 2023
Export Citation:
Assignee:
UNITED STATES GYPSUM CO (US)
International Classes:
C04B14/20; C01B33/42; C04B28/14
Attorney, Agent or Firm:
CRAIN, Lawrence et al. (US)
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Claims:
| AMENDED CLAIMS received by the International Bureau on 03 August 2023 (03.08.23) A gypsum panel having a gypsum core comprising set gypsum and ammonium- exchanged vermiculite, wherein the gypsum core has a width (x), a length (y) and a thickness (z), wherein the length (y) and the width (x) are greater than the thickness (z), wherein the length (y) is greater than the width (x), wherein the gypsum core has two long surfaces, a first long surface of a widthlength (x-y) area and an opposite second long surface of the width-length (x-y) area, and wherein each of the two long surfaces has four edges, including a first long edge of the length (y) and a second long edge of the length (y), the second long edge being opposite to the first long edge. The gypsum panel of claim 1 , wherein the gypsum core has been formed from a gypsum slurry, and wherein the gypsum slurry comprises water, calcined gypsum in an amount from 40% to 70% by weight of the slurry, ammonium-exchanged vermiculite in an amount from 2% to 10% by weight of calcined gypsum, and one or more additives, or wherein the gypsum slurry comprises water, calcined gypsum in an amount from 40% to 70% by weight of the slurry, vermiculite in an amount from 2% to 10% by weight of calcined gypsum, one or more additives, and one or more of ammonium salt, ammonium hydroxide and/or urea in a weight ratio to vermiculite ranging from 1 :5 to 1:50; and wherein a water-to-stucco ratio in the gypsum slurry is from 0.5 to 1.5. The gypsum panel of claim 1, wherein the gypsum panel is further characterized by one or more of the following features: the gypsum core contains ammonium-exchanged vermiculite of Grade 4, Grade 5, or any combination thereof; the gypsum core is covered on the first long surface with a first paper cover sheet and the gypsum core is covered on the second long surface with a second paper cover sheet, and wherein the first paper cover sheet and the second paper cover sheet are attached to the gypsum core; the gypsum core has the thickness (z) of 5/8 inch, and wherein the gypsum core has less than 5% thermal shrinkage in the z-direction, as measured in a thermal shrinkage test conducted in accordance with ASTM C 1795-15 at 850 °C for one hour; the gypsum panel is fire-rated; the gypsum core contains air voids; or the gypsum core has a density in the range from 30 pounds per cubic foot (pcf) to 40 pounds per cubic foot (pcf). The gypsum panel of claim 1, wherein the gypsum panel is characterized by one or more of the following features: at least two long edges of the gypsum core are tapered; the gypsum panel has the thickness (z) in range from % inch to 1 inch; or the gypsum panel is fire-resistant wallboard with a thermal insulation index (H) of at least 20 minutes, as measured in accordance with ASTM C 1795-15. The gypsum panel of claim 2, wherein the one or more additives include starch, fibers, a dispersant, a foaming agent, a set accelerating agent, a phosphate compound, a set retarding agent, a water repellant, or any combination thereof. A method for making a gypsum panel having a gypsum core comprising set gypsum and ammonium-exchanged vermiculite, the method comprising: a) mixing a gypsum slurry with calcined gypsum, water and additives; b) adding to the gypsum slurry ammonium-exchanged vermiculite or adding to the gypsum slurry vermiculite and one or more of ammonium salt, ammonium hydroxide and/or urea; c) depositing the gypsum slurry on a first cover sheet; and d) covering the deposited gypsum slurry with a second cover sheet. The method of claim 6, wherein the method further comprises before step b), ionexchanging vermiculite in a solution comprising one or more of ammonium salt, ammonium hydroxide and/or urea and thereby obtaining ammonium-exchanged vermiculite. The method of claim 7, wherein after the ion-exchanging reaction is completed, the method further comprises one or more of the following: separating ammonium exchanged vermiculite from the solution and/or drying ammonium-exchanged vermiculite. The method according to claim 6, wherein the method is further characterized by one or more of the following features: the additives include one or more of the following: starch, foam, fibers, a dispersant, a phosphate compound, a set retarding agent, a set accelerating agent, or any combination thereof; and/or the first cover sheet and/or the second cover sheet are paper cover sheets. A wall or ceiling assembly comprising at least one gypsum panel according to claim 1, wherein the gypsum panel is attached to a substrate. |
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