US 12,448,328 B2
Gypsum panel containing ammonium-exchanged vermiculite and methods
Qinghua Li, Rolling Meadows, IL (US); and Mark Hemphill, Hawthron Woods, IL (US)
Assigned to KNAUF GIPS KG, Iphofen (DE)
Filed by KNAUF GIPS KG, Iphofen (DE)
Filed on Sep. 20, 2022, as Appl. No. 17/948,710.
Claims priority of provisional application 63/307,818, filed on Feb. 8, 2022.
Prior Publication US 2023/0250019 A1, Aug. 10, 2023
Int. Cl. C04B 11/28 (2006.01); C01B 33/42 (2006.01); C04B 14/20 (2006.01); C04B 28/14 (2006.01); C04B 111/00 (2006.01); C04B 111/40 (2006.01)
CPC C04B 11/28 (2013.01) [C04B 2111/0062 (2013.01); C04B 2111/40 (2013.01)] 18 Claims
OG exemplary drawing
 
1. 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 width-length (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;
wherein the gypsum core has been formed from a gypsum slurry, said gypsum slurry having a water-to-stucco ratio from 0.5 to 1.5; and
wherein said gypsum slurry comprises:
a) water,
b) calcined gypsum in an amount from 40% to 70% by weight of the slurry,
c) ammonium-exchanged vermiculite in an amount from 2% to 10% by weight of calcined gypsum or vermiculite in an amount from 2% to 10% by weight of calcined gypsum in combination with one or more of ammonium salt, ammonium hydroxide or urea in a weight ratio to said vermiculite ranging from 1:5 to 1:50, and
d) one or more additives.
 
14. 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; and wherein the method further comprises before step b), ion-exchanging vermiculite in a solution comprising one or more of ammonium salt, ammonium hydroxide and/or urea and thereby obtaining ammonium-exchanged vermiculite.