WO2024097215A1 - Plaques de gypse résistantes à l'eau et leurs procédés de fabrication - Google Patents

Plaques de gypse résistantes à l'eau et leurs procédés de fabrication Download PDF

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Publication number
WO2024097215A1
WO2024097215A1 PCT/US2023/036461 US2023036461W WO2024097215A1 WO 2024097215 A1 WO2024097215 A1 WO 2024097215A1 US 2023036461 W US2023036461 W US 2023036461W WO 2024097215 A1 WO2024097215 A1 WO 2024097215A1
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Prior art keywords
water
gypsum
lbs
range
modified starch
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PCT/US2023/036461
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English (en)
Inventor
Dahlia AMATO
Remi Lespiat
Patrick Mcginley
Original Assignee
Certainteed Gypsum, Inc.
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Publication date
Priority claimed from EP23152810.0A external-priority patent/EP4361116A1/fr
Application filed by Certainteed Gypsum, Inc. filed Critical Certainteed Gypsum, Inc.
Publication of WO2024097215A1 publication Critical patent/WO2024097215A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
    • C04B28/145—Calcium sulfate hemi-hydrate with a specific crystal form
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00612—Uses not provided for elsewhere in C04B2111/00 as one or more layers of a layered structure
    • C04B2111/0062—Gypsum-paper board like materials

Definitions

  • the present disclosure relates generally to water-resistant gypsum boards and methods of making the same.
  • Gypsum building products e.g., known variously as wallboard, ceiling board, plasterboard and “drywall” are panels made of a gypsum core sandwiched between two layers of liner, often paper, on the outside surfaces of the gypsum core. They are widely used as construction materials due to their ease of fabrication, high mechanical strength, low thermal conductivity, resistance to spread of fire, and soundproofing properties.
  • the quality of a gypsum board is strongly dependent on its gypsum core, which is fabricated by the hydration of stucco slurry (mainly containing calcium sulfate hemihydrate) into a set body of calcium sulfate dihydrate.
  • additives are often added to the stucco slurry during the board making process.
  • foaming agents, inorganic compounds, and other additives may be included in the slurry to modulate the density, strength, and/or fire resistance properties of the board.
  • the present disclosure provides a water-resistant gypsum board comprising a gypsum core having a density of at least 20 lbs/ft 3 , the gypsum core comprising: a set body of calcium sulfate dihydrate; a modified starch, present in an amount in the range of 0.04-0.6 lbs/ft 3 , based on the density of the gypsum board; and a silicone oil present in an amount in the range of 0.01-0.6 lbs/ft 3 , based on the density of the gypsum board, wherein the set gypsum core is made by the method comprising: providing a slurry comprising stucco, water, a modified starch (e.g., in uncooked form) having a peak viscosity of at least 500 BU and/or at least 715 cP, present in an amount in the range of 0.04-0.6 lbs/ft 3 , based on the density of the g
  • the present disclosure provides for a method of forming a water-resistant gypsum board (e.g., a board as described herein) comprising a gypsum core having a density of at least 20 lbs/ft 3 , the method comprising: providing a slurry comprising stucco, water, a modified starch having a peak viscosity of at least 500 BU and/or 715 cP, present in an amount in the range of 0.04-0.6 lbs/ft 3 , based on the density of the gypsum core, and a silicone oil present in an amount in the range of 0.01-0.6 lbs/ft 3 , based on the density of the gypsum core; allowing the slurry to set to form a wet gypsum core; and drying the wet gypsum core at a temperature in the range of 50-350 °C to provide a set gypsum core.
  • a water-resistant gypsum board
  • FIG. 1 is a schematic cross-sectional view of a gypsum board of the disclosure.
  • the present inventors have developed a gypsum board and method for making them that improves the efficiency of silicone oil used and the overall water-resistance properties of the board.
  • silicone oils are often used to provide water-resistant properties to gypsum boards.
  • the present inventors have noted that the amount used is often in excess of that necessary on a per-unit-mass bases to compensate for the propensity for the oils to migrate to the board surface during the setting and drying of the gypsum core of the board, leaving the center of the gypsum core with relatively less water resistance.
  • the use of silicone oils in gypsum boards is becoming more expensive due to the short supply of silicone oil, especially the polymethylhydrosiloxane typically used in gypsum boards.
  • the present disclosure is concerned with improving the efficiency of silicone oil used in water-resistant gypsum boards.
  • the present inventors have found that by including a high-viscosity modified starch together with the silicone oil in the stucco slurry for making the gypsum board, and thus in the gypsum board itself, the water resistance can be improved.
  • the present inventors surmise that the use of the starch helps to limit the migration of the silicone oil in the gypsum core, and thus the silicone oil concentration can remain more uniform throughout. This means that the threshold concentration of silicone oil necessary for water resistance in the center of the gypsum core is reduced.
  • the present inventors have advantageously found a gypsum board formulation that uses less silicone oil than conventional water-resistant boards.
  • the present disclosure provides for a water-resistant gypsum board comprising a gypsum core having a density of at least 20 lbs/ft 3 .
  • the gypsum core comprises a set body of calcium sulfate dihydrate; a modified starch, present in an amount in the range of 0.04-6 lbs/ft 3 , based on the density of the gypsum core; and a silicone oil present in an amount in the range of 0.01-0.6 lbs/ft 3 , based on the density of the gypsum core.
  • the present inventors have found a water-resistant gypsum board formulation that improves the efficiency of use of silicone oil.
  • the amount of silicone oil used will vary depending on the gypsum formulation and the degree of water resistance necessary; the use of the starch as described herein can improve the degree of water resistance for a given amount of silicone oil.
  • the silicone oil is present in an amount in the range of 0.1-0.6 Ibs/ft3 based on the density of the gypsum core. In various embodiments, the silicone oil is present in an amount in the range of 0.01-0.5 lbs/ft 3 , based on the density of the gypsum core.
  • the silicone oil is present in an amount in the range of 0.01-0.3 lbs/ft 3 or 0.01-0.25 lbs/ft 3 , based on the density of the gypsum core. In various embodiments, the silicone oil is present in an amount in the range of 0.02-0.6 lbs/ft 3 , or 0.02-0.5 lbs/ft 3 , or 0.02-0.3 lbs/ft 3 , or 0.02-0.25 lbs/ft 3 , 0.05-0.6 lbs/ft 3 , or 0.05-0.5 lbs/ft 3 , or 0.05-0.3 lbs/ft 3 , or 0.05-0.25 lbs/ft 3 , or 0.1 -0.6 lbs/ft 3 , or 0.1-0.5 lbs/ft 3 , or 0.1-0.3 lbs/ft 3 , or 0.1-0.25 lbs/ft 3 , or 0.2-0.6 lbs/ft 3 , or 0.2-0.5 lbs/ff
  • the silicone oil used can react in the slurrying, setting and drying operations, e.g., by reacting with itself to provide larger molecular weight silicones.
  • the silicone oil is a hydrogen-functional silicone oil.
  • the hydride, of the hydrogen functional silicone oil is hydrolyzed to hydroxide, which can then react with other silicone oil molecules, stucco, or gypsum. This provides a network of silicone, which strengthens the gypsum board.
  • Such hydrogen-functional silicone oils can be selected from any silicone oil with hydrolysable silicon hydride (Si-H) groups.
  • the silicone oil is a polymethylhydrosiloxane (PMHS).
  • the present inventors surmise that the use of the starch helps to limit the migration of the silicone oil in the gypsum core, and thus the silicone oil concentration can remain more uniform throughout. Accordingly, in some embodiments, the silicone oil concentration in the center of the gypsum core is at least 50% of the concentration within 10% of an outer edge of the gypsum core. In some embodiments, the silicone oil concentration in the center of the gypsum core is at least 60% of the concentration within 10% of an outer edge of the gypsum core.
  • the silicone oil concentration in the center of the gypsum core is at least 65%, or at least 70%, or at least 75%, of the concentration within 10% of an outer edge of the gypsum core.
  • the silicone oil concentration in the center of the gypsum core is at least 50% of the concentration at the edge of the gypsum core.
  • the silicone oil concentration in the center of the gypsum core is at least 60 %, or at least 65%, or at least 70%, or at least 75% of the concentration at the edge of the gypsum core.
  • Center and “outer edge” in this regard refers to sites measured along the thickness axis of the board. The “center” of the core is indicated by the dashed line 120 in FIG. 1, and the “outer edge” of the core is indicated by arrows 125 in FIG. 1.
  • the gypsum core includes silicone oil is present in an amount in the range of 0.01-0.6 lbs/ft 3 . As would be understood by the skilled person, this amount is an average amount over the volume of the core, and that the concentration of the silicone oil may be different throughout layers of the core. However, as hypothesized by the present inventors, by including high-viscosity modified starches, the silicone oil concentration remains uniform throughout the core. For example, in some embodiments, the silicone oil concentration at the center of the gypsum core is at least 50% of the average amount of silicone oil present in the core.
  • the silicone oil concentration at the center of the gypsum core is at least 60%, or at least 65%, or at least 70%, or at least 75% of the average amount of the silicone oil present in the core.
  • Center and “average” in this regard refers to sites measured along the thickness axis of the board.
  • the present inventors have found it advantageous to also include a high-viscosity modified starch to in the stucco slurry that sets and dries to ultimately form the gypsum board.
  • modified starches have a high viscosity (e.g., at least 500 Brabender units (Bll), and/or at least 715 cP, each measured as described herein) and a gel temperature that is desirably below or equal to the temperature used to dry the slurry (e.g., no more than 100 °C).
  • the high viscosity modified starch gels and acts as a barrier to keep the silicone oil in place, resulting in less migration of the silicone oil to the surface of the gypsum core and thus a higher concentration of the silicone oil at the center of the gypsum core, improving the overall water resistance properties of the board.
  • the modified starch also has a high viscosity (e.g., a peak viscosity of at least 500 Bll and/or at least 715 cP).
  • a high viscosity e.g., a peak viscosity of at least 500 Bll and/or at least 715 cP.
  • the present inventors have noted in the Examples below that water-resistant boards made with high-viscosity starches have higher water resistance. Without intending to being bound by theory, it is believed, that the high viscosity of the starch helps to reduce the migration of the silicone oil within the gypsum core, and as such results in a higher concentration of silicone oil in the center of the core. And indeed, as described in more details in the Examples below, the same effects are not observed with low-viscosity starches.
  • the peak viscosity in Brabender units is measured by measuring a slurry of the modified starch in water at a concentration of 15% solids with a Viscograph-E instrument set to 75 rpm and 700 cmg, where the slurry is heated from 25 °C to 95 °C at a rate of 3°C/minute, the slurry is held at 95 °C for 10 minutes, and the slurry is cooled to 50 °C at a rate of 3 °C/minute.
  • the peak viscosity is determined as the maximum viscosity of the starch slurry measured by the above method with the Viscograph-E instrument.
  • the modified starch has a peak viscosity that is at least 500 Bll, or at least 550 Bll, or at least 600 Bll, or at least 650 Bll, or at least 700 Bll, or at least 750 Bll, or at least 800 Bll. In some embodiments, the modified starch has a peak viscosity in the range of 500-1500 Bll.
  • the modified starch has a peak viscosity in the range of 500-1400 Bll, or 500-1300 Bll, or 500-1200 Bll, or 500-1100 BU, or 500-1000 BU, or 600-1500 BU, or 600-1400 BU, or 600-1300 BU, or 600-1200 BU, or 600-1100 BU, or 700-1500 BU, or 700-1400 BU, or 700-1300 BU, or 700-1200 BU.
  • the modified starch has a peak viscosity that is at least 700 BU.
  • the modified starch has a peak viscosity in the range of 600-1500 BU.
  • the peak viscosity in units of centipoise is measured using a Discovery Hybrid Rheometer (DHR).
  • DHR Discovery Hybrid Rheometer
  • a 15% by weight suspension of starch in deionized water is loaded into the DHR using the starch cup and blade.
  • the starch suspension is subjected to a temperature profile: Hold at 25 °C for 5 min; Heat from 25 °C to 95 °C at 3 °C/min; Hold at 95 °C for 10 min; Cool from 95 °C to 50 °C at -3 °C/min.
  • the peak viscosity is determined as the maximum viscosity of the starch slurry measured by the DHR during the temperature profile.
  • the modified starch has a peak viscosity that is at least 715 cP, or at least 785 cP, or at least 855 cP, or at least 920 cP, or at least 990 cP, or at least 1060 cP, or at least 1130 cP. In some embodiments, the modified starch has a peak viscosity in the range of 715-2095 cP.
  • the modified starch has a peak viscosity in the range of 715-1960 cP, or 715-1820 cP, or 715- 1680 cP, or 715-1545 cP, or 715-1405 cP, or 855-2095 cP, or 855-1960 cP, or 855-1820 cP, or 855-1680 cP, or 855-1545 cP, or 990-2095 cP, or 990-1960 B cP, or 990-1820 cP, or 990-1680 cP.
  • the modified starch has a peak viscosity that is at least 990 cP.
  • the modified starch has a peak viscosity in the range of 920-
  • the modified starch may be a wheat starch, a tapioca starch, a corn starch, a potato starch, a pea starch or a rice starch.
  • the modified starch may be a wheat starch, a tapioca starch, or a corn starch.
  • the modified starch is a corn starch.
  • the starch is an acid-modified starch; the person of ordinary skill in the art will appreciate that acid-modification can be used to provide the starch with a desired viscosity, with a greater degree of acid modification providing a lower viscosity.
  • Various chemical functionalizations can be used to modify the starch, acid- modified or otherwise. Examples include, hydroxyalkylation (e.g., hydroxyethylation, hydroxypropylation, hydroxybutylation); acylation (e.g., acetylation); carboxymethylation; alkylation (e.g., ethylation, butylation, or propylation); succination; and oxidation.
  • hydroxyalkylation e.g., hydroxyethylation, hydroxypropylation, hydroxybutylation
  • acylation e.g., acetylation
  • carboxymethylation alkylation (e.g., ethylation, butylation, or propylation)
  • succination e.g., succination
  • oxidation e.g., oxidation
  • the starch may be cross-linked (e.g., by phosphate), although a high degree of crosslinking may not be desirable.
  • the starch is
  • the inventors surmise that functionalization can provide increased viscosity, for example, by providing sites for interaction of starch chains, e.g., by entanglement or hydrogen bonding.
  • starch chains e.g., by entanglement or hydrogen bonding.
  • Many starches suitable for use in gypsum products are commercially available; the person of ordinary skill in the art can, based on the present disclosure, select ones that have appropriate viscosities for a desired product.
  • the silicone oil and the modified starch are included in a slurry that includes stucco and water; the slurry is allowed to set to ultimately from the gypsum core, as described in more detail below.
  • the modified starch can desirably be provided to the slurry in uncooked form.
  • a pregelatinized starched (or a cooked starch) are often prepared by heating and extruding a slurry of starch. In doing so, the crystalline structure of the starch granules rupture, resulting in starches with lower gelatinization lower temperatures as compared to uncooked starches. Uncooked starches are not modified by heat or extrusion and retain the crystalline structure of the starch granules. Pregelatinized starches tend to thicken in cold water, while uncooked starches generally will not. Use of an uncooked modified starch in the slurry can allow for desirable processing.
  • the present inventors have found that by using a modified starch that is not substantially soluble in cold water, such as is the case for an uncooked modified starch, the viscosity of the slurry does not thicken substantially upon addition of the starch.
  • Using uncooked modified starches can provide operational advantages in fluid handling; the slurry can be easily processed into a board according to conventional methods known in the art. Only after the heat generated during setting do the advantages of the uncooked starch take effect.
  • the uncooked modified starch has a solubility of no more than 5 wt% in 25 °C water.
  • the uncooked modified starch has a solubility of no more than 2 wt%, e.g., no more than 1 wt% in 25 °C water.
  • Pregelatinized modified starches are often soluble in cold water and can thicken the slurry when added. While thickening of the slurry may occur, the slurry can still be processed according to conventional methods known in the art.
  • the uncooked modified starch has a cold water viscosity of no more than 50 cP, e.g., no more than 30 cP, or no more than 10 cP, in cold water (i.e., when taken up in water at a mass ratio of 0.1 :1 at a temperature of 25 °C).
  • the uncooked modified starch has a cold water viscosity of no more than 30 cP in cold water ((i.e., when taken up in water at a mass ratio of 0.1:1 at a temperature of 25 °C).
  • the cold water viscosity can be measured by a Brookfield viscometer at 25 °C by adding 20 g of dry starch to 180 g of water in a Waring blender (model 31 BL92). The starch solution is mixed at low speed for 15 seconds. The starch solution is then transferred to a measuring cup and a no. 2 paddle and 60 rpm are used. The viscosity value is measured at 20 seconds is used as the cold water viscosity of the starch.
  • the desired maximum gel temperature of the modified starch will depend on the overall process used to make the boards, and is desirably at or below the temperature used in drying the boards. As such, in some embodiments, the modified starch has a gel temperature of no more than 100 °C. In some embodiments, the modified starch has a gel temperature of no more than 95 °C (e.g., no more than 90 °C, or 85 °C, or 80 °C, or 75 °C, or 72 °C, or 70 °C). In some embodiments, the uncooked modified starch has a gel temperature in the range of 60-100 °C.
  • the modified starch as a gel temperature in the range of 60-95 °C, or 60-90 °C, or 60-85 °C, or 60-80 °C, or 60-75 °C, or 60-72 °C, or 60-70 °C, or 65-100°C, or 65-95 °C, or 60-90 °C, or 60-85 °C, or 65-80 °C, or 65-75 °C, or 65-72 °C, or 65-70 °C.
  • Starches for use herein can have a variety of molecular weights. Molecular weight can be determined via gel permeation chromatography. Samples were dissolved overnight in dimethylsulfoxide (DMSO)/ dimethylacetamide (DMAc) (80/20), LiBr 0.1% at 60°C with gentle agitation (e.g., using an orbital shaker), yielding transparent solutions with a small amount of insoluble material. The resulting solutions were filtered with 0.45pm nylon prior to analysis. Samples are subjected to gel permeation chromatography using Jordi GPC software. Test conditions are provided in the table below:
  • the starch has a weight-average molecular weight in the range of 40-100 kDa, e.g., in the range of 40-80 kDa, or 40-60 kDa, or 45-100 kDa, or 45-80 kDa, or 45-60 kDa.
  • the gypsum core includes a modified starch in an amount in the range of 0.04-0.6 lbs/ft 3 , based on the density of the gypsum core.
  • the modified starch is present in an amount in the range of 0.04-0.5 lbs/ft 3 , e.g., 0.04-0.4 lbs/ft 3 , or 0.04-0.3 lbs/ft 3 , based on the density of the gypsum core.
  • the modified starch is present in an amount in the range of 0.05-0.6 lbs/ft 3 , e.g., 0.05-0.5 lbs/ft 3 , 0.05-0.4 lbs/ft 3 , or 0.05-0.3 lbs/ft 3 , based on the density of the gypsum core. In various embodiments, the modified starch is present in an amount in the range of 0.07-0.6 lbs/ft 3 , e.g., 0.07-0.5 lbs/ft 3 , 0.07-0.4 lbs/ft 3 , or 0.07-0.3 lbs/ft 3 , based on the density of the gypsum core.
  • the modified starch is present in an amount in the range of 0.1-0.6 lbs/ft 3 , e.g., 0.1-0.5 lbs/ft 3 , 0.1-0.4 lbs/ft 3 , or 0.1-0.3 lbs/ft 3 , based on the density of the gypsum core.
  • the person of ordinary skill in the art will, based on the present disclosure, determine an appropriate amount of the starch to provide the desired water resistance, and other desirable board properties.
  • both a modified starch and silicone oil are present in the gypsum core of the water-resistant gypsum board.
  • the weight ratio of silicone oil to modified starch is at least 1 :4, or at least 1 :3.5, or at least 1 :3.
  • the weight ratio of silicone oil to modified starch is at least 1 : 1 , or at least 1.5:1 , or at least 2:1.
  • the weight ratio of silicone oil to modified starch is in the range of 1:4 to 3:1 , or 1:4 to 2.5:1 , or 1:4 to 2:1, or 1:3.5 to 3:1, or 1:3.5 to 2.5:1, or 1 :3.5 to 2:1 , or 1:3 to 3:1 , or 1:3 to 2.5:1 , or 1:3 to 2:1 , or 1:1 to 3:1 , or 1:1 to 2.5:1 , or 1:1 to 2:1.
  • the present inventors surmise that the use of the starch helps to limit the migration of the silicone oil in the gypsum core. To accomplish this effect, the present inventors hypothesize that the starch concentration remains more uniform throughout the gypsum core. Accordingly, in some embodiments, the starch concentration in the center of the gypsum core is at least 50% of the concentration within 10% of an outer edge of the gypsum core. In some embodiments, the modified starch concentration in the center of the gypsum core is at least 60% of the concentration within 10% of an outer edge of the gypsum core.
  • the starch concentration in the center of the gypsum core is at least 65%, or at least 70%, or at least 75%, of the concentration within 10% of an outer edge of the gypsum core. In some embodiments, the starch concentration in the center of the gypsum core is at least 50% of the concentration at the edge of the gypsum core. In various embodiments, the starch concentration in the center of the gypsum core is at least 60 %, or at least 65%, or at least 70%, or at least 75% of the concentration at the outer edge of the gypsum core. “Center” and “outer edge” in this regard refers to sites measured along the thickness axis of the board.
  • the gypsum core includes starch present in an amount in the range of 0.04-0.6 lbs/ft 3 . As would be understood by the skilled person, this amount is an average amount over the volume of the core, and that the concentration of the starch may be different throughout layers of the core. However, as hypothesized by the present inventors, the high-viscosity modified starches concentration remains uniform throughout the core. For example, in some embodiments, the starch concentration at the center of the gypsum core is at least 50% of the average amount of starch present in the core.
  • the starch concentration at the center of the gypsum core is at least 60%, or at least 65%, or at least 70%, or at least 75% of the average amount of the starch present in the core.
  • Center and “average” in this regard refers to sites measured along the thickness axis of the board.
  • the present disclosure relates to water-resistant gypsum boards.
  • water-resistant gypsum boards have a relatively low water absorption.
  • the water-resistant gypsum board of the present disclosure has a Test Water Absorption (see Examples) of no more than 20 wt. %, e.g., no more than 17 wt. %, or no more than 15 wt. %, based on the weight of the board.
  • the present disclosure provides for water-resistant gypsum boards having a density of at least 20 lbs/ft 3 .
  • the size and shape (e.g., length, width, and thickness) of the water- resistant gypsum board is not particularly limited, and the person of ordinary skill in the art would be able to choose an appropriate shape and size for the desired application.
  • the water-resistant gypsum board has a density of at least 25 lbs/ft 3 or at least 30 lbs/ft 3 . In some embodiments, the water-resistant gypsum board has a density in the range of 20-80 lbs/ft 3 .
  • the water-resistant gypsum board has a density in the range of 20-70 lbs/ft 3 , or 20-60 lbs/ft 3 , or 25-80 lbs/ft 3 , or 25-70 lbs/ft 3 , or 25-60 lbs/ft 3 , or 30-80 lbs/ft 3 , or 30-70 lbs/ft 3 , or 30-60 lbs/ft 3 .
  • the gypsum core may be present in the gypsum core.
  • one or more accelerators, fluidizers, retarders, dispersants, foaming agents, and/or glass fibers may be present in the gypsum core.
  • Such components may be present in a variety of amounts.
  • the components may be present in an about of no more than 5 wt%, e.g., no more than 3 wt%, or no more than 2 wt%.
  • the gypsum core is at least 75 wt% gypsum, e.g., at least 80 wt% gypsum, or at least 85 wt% gypsum.
  • gypsum boards are typically provided with liners at opposing major surfaces thereof.
  • An example of such a gypsum board is shown cross-sectional schematic view in FIG. 1.
  • gypsum board 100 having opposing major surfaces 102 and 104 includes a gypsum core 110 disposed between liner 112 (at major surface 102) and liner 114 (at major surface 104).
  • the liners can be formed, for example, from paper (which itself can be coated with a variety of substances, e.g., wax or silicone) or fiberglass. Of course, other liner materials are possible.
  • Another aspect of the present disclosure provides for a method of forming a water-resistant gypsum board having a gypsum core having a density of at least 20 lbs/ft 3 .
  • the method comprises providing a slurry comprising stucco, water, a modified starch, and a silicone oil; wherein the modified starch has a peak viscosity of at least 500 Bll and/or at least 715 cP and is present in an amount in the range of 0.04-0.6 lbs/ft 3 , based on the density of the gypsum core; and wherein the silicone oil is present in an amount in the range of 0.01-0.6 lbs/ft 3 , based on the density of the gypsum core; allowing the slurry to set to form a wet gypsum core; and drying the wet gypsum core at a temperature of 50-350 °C to provide the gypsum core.
  • stucco can have a variety of compositions depending on the source and application at hand.
  • a “stucco” is a material having at least 75 wt% of calcium sulfate hemihydrate. It is typically provided by calcining gypsum to convert the dihydrate of gypsum to hemihydrate.
  • Real-world samples of stucco typically include, together with the hemihydrate (e.g., present as a-calcium sulfate hemihydrate, - calcium sulfate hemihydrate, or combinations thereof), one or more of calcium sulfate dihydrate, calcium sulfate anhydrate, and inert calcium sulfate.
  • the method of the present disclosure includes providing a slurry that comprises stucco and water.
  • the water provides fluidity to the slurry for ease of handling, as well as provides the necessary water for hydration of the hemihydrate to gypsum.
  • the person of ordinary skill in the art will select a desirable ratio of stucco to water.
  • the weight ratio of stucco to water in the slurry is no more than 3:1, or no more than 5:2, or no more than 2:1, or no more than 7:4, or no more than 3:2.
  • the weight ratio of stucco to water is in the range of 3:1 to 1 :2, or 2:1 to 4:7, or 3:1 to 2:3, or 3:1 to 1 :1, or 5:2 to 1 :2, or 5:2 to 4:7, or 5:2 to 2:3, or 5:2 to 1 :1 , or 2:1 to 1 :2, or 2:1 to 4:7, or 2:1 to 2:3, or 2:1 to 1 :1 , or 7:4 to 1 :2, or 7:4 to 4:7, or 7:4 to 2:3, or 7: 1 to 1 : 1 , or 3:2 to 1 :2, or 3:2 to 4:7, or 3:2 to 2:3, or 3:2 to 1 : 1.
  • the stucco is desirably present in the slurry to provide the set and a gypsum core with at least 75 wt% gypsum, e.g., at least 80 wt% gypsum, or at least 85 wt% gypsum.
  • the silicone oil can be as described in any embodiment described above with respect to the gypsum boards of the disclosure.
  • the person of ordinary skill in the art can provide silicon oil in the slurry in an amount sufficient to provide a total amount of silicone oil in the gypsum core as described above with respect to any of the gypsum board embodiments.
  • the modified starch can be as described in any embodiment described above with respect to the gypsum boards of the disclosure.
  • the person of ordinary skill in the art can provide modified starch in the slurry in an amount sufficient to provide a total amount of modified starch in the gypsum core as described above with respect to any of the gypsum board embodiments.
  • any of the weight ratio of silicone oil to modified starch in the slurry; the water absorption of the board made by the method; the board density; and the overall board structure can be as described in any embodiment above.
  • additives may be present in the slurry.
  • one or more accelerators, fluidizers, retarders, dispersants, foaming agents, and/or glass fibers maybe be present in the slurry.
  • either pregelatinized or uncooked starch maybe used in the slurry.
  • the starch does not immediately gel when included in the slurry, such that use of the starch does not substantially increase the viscosity of the slurry.
  • it can be desirable to use an uncooked starch.
  • a slump size is measured.
  • the slurry has a slump size (measured as described in the Examples) in the range of 6 to 15 inches, e.g., 6 to 12 inches, or 8 to 20 inches, or 8 to 15 inches, or 9 to 12 inches.
  • the person of ordinary skill in the art can use conventional methods to form the slurry into a board.
  • the slurry can be dispensed between opposing liners, allowed to set, then dried.
  • drying occurs at a temperature in the range of 50-350 °C to provide the set gypsum core. In some embodiments, drying occurs at a temperature in the range of 50-325 °C or 50-300 °C (i.e., measured in the environment above the board during drying, e.g., in a drying oven).
  • drying occurs at a temperature in the range of 100- 350 °C, or 100-325 °C, or 100-300 °C, or 150-350 °C, or 150-325 °C, or 150-300 °C, or 200- 350 °C, or 200-325 °C, or 200-300 °C.
  • Drying may be accomplished with an oven, wherein the oven temperature is in the range of 50-350 °C, or 50-325 °C, or 50-300°C, or 100-350 °C, or 100-325 °C, or 100-300 °C, or 150-350 °C, or 150-325 °C, or 150-300 °C, or 200-350 °C, or 200-325 °C, or 200-300 °C.
  • the temperature of the gypsum core does not exceed 125 °C, e.g., does not exceed 120 °C, 115 °C, 110 °C, or 105 °C.
  • the three starches used include Supercore® S23F (acid-modified corn starch from Grain Processing Corporation) (peak viscosity 76 BU/128.3 cP), Clinton 240 (acid-modified corn starch from Archer Daniels Midland) (peak viscosity 728 BU/1029.5 cP), and Ethylex® 2075 (a hydroxyethylated corn starch from Primary Products Ingredients Americas LLC) (peak viscosity 1157 BU/1473 cP); and the silicone oil used was BS94 polymethylhydrosiloxane (from Wacker). Starch viscosities and molecular weights were measured as described in the specification.
  • the gypsum slurries where then measured for their slump size. To do so, after mixing the slurry, a portion was poured into a 2” diameter x 4” height cylinder sitting on the center of a 12” x 12” glass plate; filling the cylinder to the brim. A knife was used to remove any extra slurry to ensure that the cylinder was not overflowing. Immediately after filling the cylinder, the cylinder was lifted straight up, perpendicular to the plate. Once the slurry had stiffened (such that a knife can cleanly cut through the slurry), four diameters of the slurry was measured, averaged, and recorded as the slump size. The target slump size is 9 ⁇ 0.5 inches. Slump sizes as described throughout the disclosure are measured as described here.
  • the gypsum slurries were also formed into a board samples with paper liners disposed on both the top and bottom of the board.
  • the board samples were prepared in 7” x 7” squares.
  • Table 1 provides the formulations of the board samples tested and the slump size of the slurries.
  • the gypsum board samples were then tested for their water absorption.
  • the sample tested for water absorption was 3.8” x 3.8” cut from the center of the board sample.
  • Water absorptions measured in this fashion are “Test Water Absorptions” for the purposes of this disclosure.
  • the gypsum board samples were first weighed. Then, they were placed on glass rods on a support in a water bath with a head of 1 inches of water over the top of the sample. The glass rods provide a gap of 6 mm between the sample and the support, allowing all sides of the sample to be exposed wot water. Glass rods were placed on top of the sample to keep the sample in contact with the support under the 1 inch of water. The samples were kept under water for 2 hours. Excess water was wiped from the surfaces and edges of the sample and then weighed. The Test Water Absorption was calculated based on the following equation:
  • Test Water Absorption (%) ((Mass 2 hours - Massmitiai)/ Massmitiai) x 100
  • Table 2 reports the Test Water Absorption for each sample tested as described above.
  • Example 1 Three gypsum board samples were prepared as described in Example 1.
  • the boards included three starches with different viscosities as well as silicone oil in varying amounts.
  • the silicone oil used was polymethylhydrosiloxane.
  • the gypsum slurries were made using a ratio of gypsum to water of 1.35, based on weight.
  • Table 3 describes the formulation of the gypsum board samples. The finished board samples where then tested for their Test Water Absorption, as described in Example 1. [0062] Table 3.
  • Table 4 reports the Test Water Absorption for each sample tested as described above.
  • Embodiment 1 A water-resistant gypsum board comprising a set gypsum core having a density of at least 20 lbs/ft 3 , wherein the set gypsum core comprises: a set body of calcium sulfate dihydrate; a modified starch present in an amount in the range of 0.04-0.6 lbs/ft 3 , based on the density of the gypsum core; and a silicone oil present in an amount in the range of 0.01-0.6 lbs/ft 3 , based on the density of the gypsum core wherein the set gypsum core is made by the method comprising: providing a slurry comprising stucco, water, a modified starch having a peak viscosity of at least 500 Bll and/or at least 715 cP, present in an amount in the range of 0.04-0.6 lbs/ft 3 , based on the density of the gypsum core, and a silicone oil present in an amount in the range
  • Embodiment 2 The water-resistant gypsum board Embodiment 1, wherein the silicone oil is present an amount in the range of 0.01-0.5 lbs/ft 3 (e.g., in the range of 0.01-0.3 lbs/ft 3 , or 0.01-0.25 lbs/ft 3 ) based on the density of the gypsum core.
  • the silicone oil is present an amount in the range of 0.01-0.5 lbs/ft 3 (e.g., in the range of 0.01-0.3 lbs/ft 3 , or 0.01-0.25 lbs/ft 3 ) based on the density of the gypsum core.
  • Embodiment 3 The water-resistant gypsum board of Embodiment 1 or Embodiment 2, wherein the silicone oil is present in an amount in the range of 0.05-0.6 lbs/ft 3 (e.g., in the range of 0.05-0.5 lbs/ft 3 , or 0.05-0.3 lbs/ft 3 , or 0.05-0.25 lbs/ft 3 ) based on the density of the gypsum core.
  • Embodiment 4 The water-resistant gypsum board of Embodiment 1 or Embodiment 2, wherein the silicone oil is present in an amount in the range of 0.1-0.6 lbs/ft 3 (e.g., in the range of 0.1-0.5 lbs/ft 3 , or 0.1-0.3 lbs/ft 3 , or 0.1-0.25 lbs/ft 3 ) based on the density of the gypsum core.
  • Embodiment 5 The water-resistant gypsum board of Embodiment 1 or Embodiment 2, wherein the silicone oil is present in an amount in the range of 0.2-0.6 lbs/ft 3 (e.g., in the range of 0.2-0.5 lbs/ft 3 , or 0.2-0.3 lbs/ft 3 , or 0.2-0.25 lbs/ft 3 ) based on the density of the gypsum core.
  • Embodiment 6 The water-resistant gypsum board of any of Embodiments 1-5, wherein the silicone oil is a hydrogen-functional silicone.
  • Embodiment 7 The water-resistant gypsum board of Embodiment 6, wherein the silicone oil is a polymethylhydrosiloxane.
  • Embodiment 8 The water-resistant gypsum board of any of Embodiments 1-7, wherein the silicone oil concentration in the center of the gypsum core is at least 50% of the concentration within 10% of an outer edge of the gypsum core.
  • Embodiment 9 The water-resistant gypsum board of any of Embodiments 1-8, wherein the silicone oil concentration in the center of the gypsum core is at least 60% (e.g., at least 65%, or 70%, or 75%) of the concentration within 10% of an outer edge of the gypsum core.
  • Embodiment 10. The water-resistant gypsum board of any of Embodiments 1-9, wherein the silicone oil concentration in the center of the gypsum core is at least 50% of the concentration at the edge of the gypsum core.
  • Embodiment 11 The water-resistant gypsum board of any of Embodiments 1-10, wherein the silicone oil concentration in the center of the gypsum core is at least 60% (e.g., at least 65%, or 70%, or 75%) of the concentration at the edge of the gypsum core.
  • Embodiment 12 The water-resistant gypsum board of any of Embodiments 1-11, wherein the silicone oil concentration at the center of the gypsum core is at least 50% of the average amount of silicone oil present in the core.
  • Embodiment 13 The water-resistant gypsum board of any of Embodiments 1-12, wherein the silicone oil concentration at the center of the gypsum core is at least 60% (e.g., at least 65%, or 70%, or 75%) of the average amount of the silicone oil present in the core.
  • Embodiment 14 The water-resistant gypsum board of any of Embodiments 1-13, wherein the modified starch has a peak viscosity that is at least 500 Bll (e.g., at least 550 Bll, or at least 650 Bll, or at least 700 Bll, or at least 750 Bll, or at least 800 Bll).
  • the modified starch has a peak viscosity that is at least 500 Bll (e.g., at least 550 Bll, or at least 650 Bll, or at least 700 Bll, or at least 750 Bll, or at least 800 Bll).
  • Embodiment 15 The water-resistant gypsum board of any of Embodiments 1-13, wherein the modified starch has a peak viscosity in the range or 500-1500 Bll (e.g., in the range of 500-1400 BU, or 500-1300 BU, or 500-1200 BU, or 500-1100 BU, or 500-1000 BU).
  • 500-1500 Bll e.g., in the range of 500-1400 BU, or 500-1300 BU, or 500-1200 BU, or 500-1100 BU, or 500-1000 BU.
  • Embodiment 16 The water-resistant gypsum board of any of Embodiments 1-13, wherein the modified starch has a peak viscosity in the range or 600-1500 BU (e.g., in the range of 600-1400 BU, or 600-1300 BU, or 600-1200 BU, or 600-1100 BU).
  • Embodiment 17 The water-resistant gypsum board of any of Embodiments 1-13, wherein the modified starch has a peak viscosity in the range or 700-1500 Bll (e.g., in the range of 700-1400 BU, or 700-1300 BU, or 700-1200 BU).
  • Embodiment 18 The water-resistant gypsum board of any of Embodiments 1-17, wherein the modified starch has a peak viscosity that is at least 715 cP (e.g., at least 785 cP, or at least 855 cP, or at least 920 cP, or at least 990 cP, or at least 1060 cP, or at least 1130 cP).
  • the modified starch has a peak viscosity that is at least 715 cP (e.g., at least 785 cP, or at least 855 cP, or at least 920 cP, or at least 990 cP, or at least 1060 cP, or at least 1130 cP).
  • Embodiment 19 The water-resistant gypsum board of any of Embodiments 1-17, wherein the modified starch has a peak viscosity in the range or 715-2095 cP (e.g., in the range of 715-1960 cP, or 715-1820 cP, or 715-1680 cP, or 715-1545 cP, or 715-1405 cP).
  • the modified starch has a peak viscosity in the range or 715-2095 cP (e.g., in the range of 715-1960 cP, or 715-1820 cP, or 715-1680 cP, or 715-1545 cP, or 715-1405 cP).
  • Embodiment 20 The water-resistant gypsum board of any of Embodiments 1-17, wherein the modified starch has a peak viscosity in the range or 855-2095 cP (e.g., in the range of 855-1960 cP, or 855-1820 cP, or 855-1680 cP, or 855-1545 cP).
  • the modified starch has a peak viscosity in the range or 855-2095 cP (e.g., in the range of 855-1960 cP, or 855-1820 cP, or 855-1680 cP, or 855-1545 cP).
  • Embodiment 21 The water-resistant gypsum board of any of Embodiments 1-17, wherein the modified starch has a peak viscosity in the range or 990-2095 cP (e.g., in the range of 990-1960 B cP, or 990-1820 cP, or 990-1680).
  • Embodiment 22 The water-resistant gypsum board of any of Embodiments 1-21, wherein the modified starch is a corn starch.
  • Embodiment 23 The water-resistant gypsum board of any of Embodiments 1-21, wherein the modified starch is a wheat starch, a tapioca starch, a potato starch, a pea starch or a rice starch.
  • Embodiment 24 The water-resistant gypsum board of any of Embodiments 1-23, wherein the modified starch is an acid-modified starch.
  • Embodiment 25 The water-resistant gypsum board of any of Embodiments 1-24, wherein the modified starch is a functionalized starch.
  • Embodiment 26 The water-resistant gypsum board of any of Embodiments 1-25, wherein the modified starch is a hydroxyalkylated starch (e.g., hydroxyethylated, hydroxypropylated, hydroxybutylated).
  • the modified starch is a hydroxyalkylated starch (e.g., hydroxyethylated, hydroxypropylated, hydroxybutylated).
  • Embodiment 27 The water-resistant gypsum board of any of Embodiments 1-25, wherein the modified starch is a hydroxyethylated starch.
  • Embodiment 28 The water-resistant gypsum board of any of Embodiments 1-27, wherein the modified starch is an acylated starch (e.g., an acetylated starch); a carboxymethylated starch; a succinated starch; and/or an oxidized starch.
  • an acylated starch e.g., an acetylated starch
  • carboxymethylated starch e.g., a carboxymethylated starch
  • a succinated starch e.g., an oxidized starch.
  • Embodiment 29 The water-resistant gypsum board of any of Embodiments 1-28, wherein the modified starch concentration in the center of the gypsum core is at least 50% of the concentration within 10% of an outer edge of the gypsum core.
  • Embodiment 30 The water-resistant gypsum board of any of Embodiments 1-29, wherein the modified starch concentration in the center of the gypsum core is at least 60% (e.g., at least 65%, or 70%, or 75%) of the concentration within 10% of an outer edge of the gypsum core.
  • Embodiment 31 The water-resistant gypsum board of any of Embodiments 1-30, wherein the modified starch concentration in the center of the gypsum core is at least 50% of the concentration at the edge of the gypsum core.
  • Embodiment 32 The water-resistant gypsum board of any of Embodiments 1-31, wherein the modified starch concentration in the center of the gypsum core is at least 60% (e.g., at least 65%, or 70%, or 75%) of the concentration at the edge of the gypsum core.
  • Embodiment 33 The water-resistant gypsum board of any of Embodiments 1-32, wherein the modified starch concentration at the center of the gypsum core is at least 50% of the average amount of modified starch present in the core.
  • Embodiment 34 The water-resistant gypsum board of any of Embodiments 1-33, wherein the modified starch concentration at the center of the gypsum core is at least 60% (e.g., at least 65%, or 70%, or 75%) of the average amount of the modified starch present in the core.
  • Embodiment 35 The water-resistant gypsum board of any of Embodiments 1-34, wherein the modified starch is a pregelatinized modified starch.
  • Embodiment 36 The water-resistant gypsum board of any of Embodiments 1-34, wherein the modified starch is uncooked when provided to the slurry.
  • Embodiment 37 The water-resistant gypsum board of Embodiment 36, wherein the uncooked modified starch has a gel temperature of no more than 100 °C (e.g., no more than 95 °C, or 90 °C, or 85 °C, or 80 °C, or 75 °C, or 72 °C, or 70 °C).
  • Embodiment 38 The gel temperature of no more than 100 °C (e.g., no more than 95 °C, or 90 °C, or 85 °C, or 80 °C, or 75 °C, or 72 °C, or 70 °C).
  • 60-100°C e.g., in the range of 60-95 °C, or 60-90 °C, or 60-85 °C, or 60-80 °C, or 60-75 °C, or 60-72 °C, or 65-70 °C.
  • Embodiment 39 The water-resistant gypsum board of any of Embodiments 36-38, wherein the uncooked modified starch has a solubility of no more than 5 wt% in 25 °C water.
  • Embodiment 40 The water-resistant gypsum board of any of Embodiments 36-38, wherein the uncooked modified starch solubility of no more than 2 wt%, e.g., no more than 1 wt% of 25 °C water.
  • Embodiment 41 The water-resistant gypsum board of any of Embodiments 36-40, wherein the uncooked modified starch has a cold water viscosity of no more than 50 cP (e.g., no more than 30 cP, or no more than 10 cP) in cold water (i.e. at a temperature of 25 °C).
  • cP e.g., no more than 30 cP, or no more than 10 cP
  • Embodiment 42 The water-resistant gypsum board of any of Embodiments 36-41 , wherein the modified starch is present in an amount in the range of 0.04-0.5 lbs/ft 3 (e.g., in the range of 0.04-0.4 lbs/ft 3 , or 0.04-0.3 lbs/ft 3 ) based on the density of the gypsum board.
  • Embodiment 43 The water-resistant gypsum board of any of Embodiments 36-41 , wherein the modified starch is present in an amount in the range of 0.07-0.6 lbs/ft 3 (e.g., in the range of 0.07-0.5 lbs/ft 3 , 0.07-0.4 lbs/ft 3 , or 0.07-0.3 lbs/ft 3 ) based on the density of the gypsum board.
  • Embodiment 44 Embodiment 44.
  • the water-resistant gypsum board of any of Embodiments 36-41 wherein the modified starch is present in an amount in the range of 0.1 -0.6 lbs/ft 3 (e.g., in the range of 0.1-0.5 lbs/ft 3 , 0.1-0.4 lbs/ft 3 , or 0.1-0.3 lbs/ft 3 ) based on the density of the gypsum board.
  • Embodiment 45 The water-resistant gypsum board of any of Embodiments 1-44, wherein the weight ratio of silicone oil to modified starch is at least 1 :4 (e.g., at least 1 :3.5, or at least 1 :3).
  • Embodiment 46 The water-resistant gypsum board of any of Embodiments 1-45, wherein the weight ratio of silicone oil to modified starch is at least 1 :1 (e.g., at least 1.5:1 , or 2:1).
  • Embodiment 47 The water-resistant gypsum board of any of Embodiments 1-46, wherein the weight ratio of silicone oil to modified starch is in the range of 1 :4 to 3:1 (e.g., 1 :4 to 3:1 , or 1 :4 to 2.5:1 , or 1 :4 to 2:1 , or 1 :3.5 to 3:1 , or 1 :3.5 to 2.5:1 , or 1 :3.5 to 2:1 , or 1 :3 to 3:1 , or 1 :3 to 2.5:1 , or 1 :3 to 2:1 , or 1 :1 to 2.5:1 , or 1 :1 to 2:1).
  • 1 :4 to 3:1 e.g., 1 :4 to 3:1 , or 1 :4 to 2.5:1 , or 1 :4 to 2:1 , or 1 :3.5 to 3:1 , or 1 :3.5 to 2.5:1 , or 1 :3.5 to 2:1 , or 1 :3 to 3:1.
  • Embodiment 48 The water-resistant gypsum board of any of Embodiments 1-47 having a Test Water Absorption (see Examples) of no more than 20 wt. %, e.g., no more than 17 wt. %, or no more than 15 wt. %, based on the weight of the board.
  • Test Water Absorption see Examples
  • Embodiment 49 The water-resistant gypsum board of any of Embodiments 1-48 having a density of at least 25 lbs/ft 3 (e.g., at least 30 lbs/ft 3 ).
  • Embodiment 50 The water resistant gypsum board of any of Embodiments 1-48 having a density in the range of 20-80 lbs/ft 3 (e.g., in the range 20-70 lbs/ft 3 , or 20-60 lbs/ft 3 ), or 25- 80 lbs/ft 3 (e.g., in the range of 25-70 lbs/ft 3 , or 25-60 lbs/ft 3 ), or 30-80 lbs/ft 3 (e.g., in the range of 30-70 lbs/ft 3 , or 30-60 lbs/ft 3 ).
  • 20-80 lbs/ft 3 e.g., in the range 20-70 lbs/ft 3 , or 20-60 lbs/ft 3
  • 25- 80 lbs/ft 3 e.g., in the range of 25-70 lbs/ft 3 , or 25-60 lbs/ft 3
  • 30-80 lbs/ft 3 e.g., in the range of
  • Embodiment 51 The water-resistant gypsum board of any of Embodiments 1-50, wherein the gypsum core is disposed between a first liner at a first major surface of the gypsum board and a second liner at a second, opposing major surface of the board.
  • Embodiment 52 The water-resistant gypsum board of Embodiment 51 , wherein the liners are paper liners.
  • Embodiment 53 A method of forming a water-resistant gypsum board comprising a gypsum core having a density of at least 20 lbs/ft 3 (e.g., a board of any of Embodiments 1- 52), the method comprising: providing a slurry comprising stucco, water, a modified starch (e.g., uncooked) having a peak viscosity of at least 500 Bll and/or at least 715 cP, present in an amount in the range of 0.04-0.6 lbs/ft 3 , based on the density of the gypsum core, and a silicone oil present in an amount in the range of 0.01-0.6 lbs/ft 3 , based on the density of the gypsum core; allowing the slurry to set to form a wet gypsum core; and drying the wet gypsum core at a temperature in the range of 50-350 °C to provide a set gypsum core.
  • Embodiment 54 The method of Embodiment 53, wherein the weight ratio of stucco to water is no more than 2:1 (e.g., no more than 7:4, or no more than 3:2).
  • Embodiment 55 The method of Embodiment 53, wherein the weight ratio of stucco to water is in the range of 2:1 to 1 :2 (e.g., in the range of 2:1 to 4:7, or 2:1 to 2:3, or 2:1 to 1 :1 , or 7:4 to 1:2, or 7:4 to 4:7, or 7:4 to 2:3, or 7:1 to 1 :1, or 3:2 to 1 :2, or 3:2 to 4:7, or 3:2 to 2:3, or 3:2 to 1:1).
  • 2:1 to 1 :2 e.g., in the range of 2:1 to 4:7, or 2:1 to 2:3, or 2:1 to 1 :1 , or 7:4 to 1:2, or 7:4 to 4:7, or 7:4 to 2:3, or 7:1 to 1 :1, or 3:2 to 1 :2, or 3:2 to 4:7, or 3:2 to 2:3, or 3:2 to 1:1.
  • Embodiment 56 The method of any of Embodiments 53-55, wherein stucco is present in the slurry to provide the set and dried gypsum core with at least 75 wt. % gypsum, e.g., at least 80 wt% gypsum or at least 85 wt% gypsum.
  • Embodiment 57 The method of any of Embodiments 53-57, wherein the amount of silicone oil present in the slurry provides silicone oil in the set and dried gypsum core in an amount as described in any of Embodiments 2-5 or Embodiments 8-13.
  • Embodiment 58 The method of any of Embodiments 53-57, wherein the silicone oil is as described in any of Embodiments 6 and 7.
  • Embodiment 59 The method of any of Embodiments 53-58, wherein the modified starch is as described in any of Embodiments 14-41.
  • Embodiment 60 The method of any of Embodiments 53-59, wherein the amount of modified starch present in the slurry is sufficient to provide starch in the set and dried gypsum core in an amount as described in any of Embodiments 42-44.
  • Embodiment 61 The method of any of Embodiments 53-60, wherein the weight ratio of silicone oil to modified starch in the slurry is as described in any of Embodiments 45-47.
  • Embodiment 62 The method of any of Embodiments 53-61 , wherein the gypsum board has a water absorption as described in Embodiment 48.
  • Embodiment 63 The method of any of Embodiments 53-62, wherein the board has a density as described in Embodiment 49 or Embodiment 50, or a structure as described in Embodiment 51 or Embodiment 52.
  • Embodiment 64 The method of forming a water-resistant gypsum board of any of Embodiments 53-63, wherein the slurry has a slump size in the range of 6 to 20 inches (e.g., in the range of 6 to 15 inches, or 6 to 12 inches, or 8 to 20 inches, or 8 to 15 inches, or 8 to 12 inches).
  • Embodiment 65 The method of forming a water-resistant gypsum board of any of Embodiments 53-64, wherein the drying occurs at a temperature in the range of 50-325 °C (e.g., in the range of 50-300 °C).
  • Embodiment 66 The method of forming a water-resistant gypsum board of any of Embodiments 53-64, wherein the drying occurs at a temperature in the range of 100-350 °C (e.g., in the range of 100-325 °C, or 100-300 °C).
  • Embodiment 67 The method of forming a water-resistant gypsum board of any of Embodiments 53-64, wherein the drying occurs at a temperature in the range of 150-350 °C (e.g., in the range of 150-325 °C, or 150-300 °C).
  • Embodiment 68 The method of forming a water-resistant gypsum board of any of Embodiments 53-64, wherein the drying occurs at a temperature in the range of 200-350 °C (e.g., in the range of 200-325 °C, or 200-300 °C).
  • each embodiment disclosed herein can comprise, consist essentially of or consist of its particular stated element, step, ingredient or component.
  • the transition term “comprise” or “comprises” means includes, but is not limited to, and allows for the inclusion of unspecified elements, steps, ingredients, or components, even in major amounts.
  • the transitional phrase “consisting of” excludes any element, step, ingredient or component not specified.
  • the transition phrase “consisting essentially of” limits the scope of the embodiment to the specified elements, steps, ingredients or components and to those that do not materially affect the embodiment.

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Abstract

La présente divulgation concerne d'une manière générale une plaque de gypse résistante à l'eau présentant une masse volumique d'au moins 20 livres/pieds3 comprenant : un noyau de gypse, le noyau de gypse comprenant : du sulfate de calcium dihydraté ; un amidon modifié présentant une viscosité au pic d'au moins 500 BU et/ou d'au moins 715 cP, présent en une quantité dans la plage de 0,04 à 0,6 livre/pied3, sur la base de la masse volumique de la plaque de gypse ; et une huile de silicone présente en une quantité dans la plage de 0,01 à 0,6 livre/pied3, sur la base de la masse volumique de la plaque de gypse.
PCT/US2023/036461 2022-10-31 2023-10-31 Plaques de gypse résistantes à l'eau et leurs procédés de fabrication WO2024097215A1 (fr)

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EP23152810.0 2023-01-23
EP23152810.0A EP4361116A1 (fr) 2022-10-31 2023-01-23 Plaques de plâtre résistant à l'eau et leurs procédés de fabrication

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017140784A1 (fr) * 2016-02-19 2017-08-24 Etex Building Performance International Sas Plaque de plâtre
US20190023614A1 (en) * 2017-07-18 2019-01-24 United States Gypsum Company Gypsum composition comprising uncooked starch having mid-range viscosity, and methods and products related thereto
CN110759693A (zh) * 2018-07-27 2020-02-07 北新集团建材股份有限公司 一种利用磷石膏和脱硫石膏生产耐水纸面石膏板的方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017140784A1 (fr) * 2016-02-19 2017-08-24 Etex Building Performance International Sas Plaque de plâtre
US20190023614A1 (en) * 2017-07-18 2019-01-24 United States Gypsum Company Gypsum composition comprising uncooked starch having mid-range viscosity, and methods and products related thereto
CN110759693A (zh) * 2018-07-27 2020-02-07 北新集团建材股份有限公司 一种利用磷石膏和脱硫石膏生产耐水纸面石膏板的方法

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