EP4511342A1 - Accélérateur de prise de gypse - Google Patents

Accélérateur de prise de gypse

Info

Publication number
EP4511342A1
EP4511342A1 EP23723725.0A EP23723725A EP4511342A1 EP 4511342 A1 EP4511342 A1 EP 4511342A1 EP 23723725 A EP23723725 A EP 23723725A EP 4511342 A1 EP4511342 A1 EP 4511342A1
Authority
EP
European Patent Office
Prior art keywords
gypsum
set accelerator
calcium sulfate
weight
range
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP23723725.0A
Other languages
German (de)
English (en)
Inventor
Naser Aldabaibeh
Mark Antosh
Mark Hemphill
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Knauf Gips KG
Original Assignee
Knauf Gips KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US17/978,406 external-priority patent/US20230339811A1/en
Application filed by Knauf Gips KG filed Critical Knauf Gips KG
Publication of EP4511342A1 publication Critical patent/EP4511342A1/fr
Pending legal-status Critical Current

Links

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
    • C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
    • C04B40/0028—Aspects relating to the mixing step of the mortar preparation
    • C04B40/0039—Premixtures of ingredients
    • C04B40/0042—Powdery mixtures
    • 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
    • C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
    • C04B20/02—Treatment
    • C04B20/026—Comminuting, e.g. by grinding or breaking; Defibrillating fibres other than asbestos
    • 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
    • C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators or shrinkage compensating agents
    • C04B22/08—Acids or salts thereof
    • C04B22/14—Acids or salts thereof containing sulfur in the anion, e.g. sulfides
    • C04B22/142—Sulfates
    • C04B22/143—Calcium-sulfate
    • 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
    • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
    • C04B24/16—Sulfur-containing compounds
    • C04B24/20—Sulfonated aromatic compounds
    • C04B24/22—Condensation or polymerisation products thereof
    • C04B24/223—Sulfonated melamine-formaldehyde condensation products
    • 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
    • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
    • C04B24/24—Macromolecular compounds
    • C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B24/2641—Polyacrylates; Polymethacrylates
    • C04B24/2647—Polyacrylates; Polymethacrylates containing polyether side chains
    • 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
    • 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
    • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
    • C04B2103/10—Accelerators; Activators
    • C04B2103/12—Set accelerators
    • 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
    • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
    • C04B2103/52—Grinding aids; Additives added during grinding

Definitions

  • Gypsum panels and other products containing set gypsum are commonly used in building construction, including wallboard, fiberboards, cementitious panels, fiberglassmat panels, floor underlayment, molded (sculptured) elements, floor underlayment and many others.
  • Manufacturing of gypsum products may include mixing calcined gypsum with water and additives into a gypsum slurry and then forming a product from the gypsum slurry which sets as calcined gypsum reacts with water and rehydrates.
  • Various methods are known in the art for controlling the setting reaction in the gypsum slurry by which calcined gypsum (calcium sulfate hemihydrate) interacts with water molecules and re-hydrates into calcium sulfate dehydrate crystals, causing the gypsum slurry to set (harden) into an interwoven matrix of set gypsum.
  • U.S. Patent 6,379,458 discloses a set accelerator for at least one of accelerating the hydration rate and reducing the set time of an aqueous slurry of calcium sulfate hemihydrate.
  • the set accelerator consists of a mixture of ground calcium sulfate dihydrate and a zinc sulfate material.
  • this disclosure provides a gypsum set accelerator, wherein the gypsum set accelerator is a dry-milled mixture comprising calcium sulfate dihydrate coground with one or more of the following: a polycarboxylic ether (PCE) and/or sulfonated melamine polycondensate (SMP).
  • PCE polycarboxylic ether
  • SMP sulfonated melamine polycondensate
  • the gypsum set accelerator may comprise from 0.1 to 5 parts by weight of the PCE and/or SMP per 100 parts by weight of calcium sulfate dihydrate, and preferably the gypsum set accelerator may comprise from 1 to 2 parts by weight of the PCE and/or SMP per 100 parts by weight of calcium sulfate dihydrate.
  • the gypsum set accelerator does not contain starch or sugar.
  • the gypsum set accelerators include those in which calcium sulfate dihydrate is sourced as mined gypsum, synthetic gypsum, re-hydrated calcined gypsum and/or scrap gypsum wallboard.
  • the method embodiments include those, wherein calcium sulfate dihydrate is sourced as gypsum, gypsum, landplaster, synthetic gypsum and/or rehydrated calcined gypsum.
  • the co-grinding in step (ii) may be performed without adding starch or sugar.
  • the co-grinding in step (ii) may be performed at a temperature in the range from 60 °F to 160 °F.
  • the ball mill may contain grinding balls with an average diameter in the range from about 10 mm to about 50 mm.
  • the co-grinding in step (ii) may be performed for a period of time in the range 5 minutes to 2 hours.
  • the forming of the gypsum product step (iv) may include spreading the gypsum slurry on a first cover sheet moving on a conveyor and covering the spread gypsum slurry with a second cover sheet as the gypsum slurry is conveyed on the first cover sheet.
  • Fig. 1 is a comparative analysis comparing a time necessary to reach a 50% hydration in a gypsum slurry prepared as follows: with freshly ground landplaster or aged landplaster (“no grinding aid bars”); with freshly ground HRA containing 5% dextrose or aged ground HRA containing 5% dextrose (“5% dextrose bars”); with a first freshly ground accelerator according to this disclosure or a first aged accelerator according to this disclosure (“1% Melment FUG”), or a second freshly ground accelerator according to this disclosure or a second aged accelerator according to this disclosure (“1% Melflux 2641”).
  • Fig. 2 is a comparative analysis for different gypsum set accelerators as follows: a setting reaction for a calcined gypsum slurry prepared with an accelerator according to this disclosure (curve I), with an HRA (curve II); or ground landplaster (curve III), where all accelerators were prepared in a ball mill at 160 °F.
  • this disclosure relates to a gypsum set accelerator which accelerates a hydration reaction of calcium sulfate hemihydrate into calcium sulfate dihydrate crystals, as shown in the following equation: [0029]
  • the term “calcined gypsum” may be used interchangeably with calcium sulfate hemihydrate, stucco, calcium sulfate semi-hydrate, calcium sulfate halfhydrate or plaster of Paris.
  • gypsum includes naturally mined gypsum (ore), landplaster as well as synthetic gypsum.
  • gypsum may be used interchangeably with the term “calcium sulfate dihydrate.”
  • dry a powder, a compound, a composition or mixture may be referred to as “dry.”
  • dry means that no water was added to the composition or mixture. Nevertheless, dry powder or dry mixture may have some moisture content.
  • dry gypsum or the dry gypsum set accelerator may have a moisture content of about 1 wt% or less, about 0.05 wt% or less, or about 0 wt%.
  • the term “about” means a range of plus/minus 5% of the value. For example, about 100 means 100+5.
  • wt% means percentage by weight.
  • the gypsum set accelerator according to this disclosure is a dry-milled mixture comprising calcium sulfate dihydrate co-ground with one or more of the following compounds: a polycarboxylic ether (PCE) and/or a sulphonated melamine polycondensate (SMP), wherein the PCE and/or SMP acts as a grinding aid.
  • PCE polycarboxylic ether
  • SMP sulphonated melamine polycondensate
  • the PCE and/or SMP is used in powder form.
  • the set accelerator may comprise from about 0.1 to about 5 parts by weight of a PCE and/or SMP in powder form per 100 parts by weight of calcium sulfate dihydrate and preferably, from about 1 to about 2 parts by weight of one or more PCEs and/or SMPs per 100 parts by weight of calcium sulfate dihydrate.
  • the gypsum set accelerator according to this disclosure does not need to contain other grinding aids, such as for example, starch, sucrose, dextrose, or any other sugar.
  • the gypsum set accelerator according to this disclosure does not comprise starch, sucrose, or dextrose.
  • the gypsum set accelerator according to this disclosure has several technical advantages over the heat resistance accelerator (“HRA”) commonly used in the art.
  • HRA heat resistance accelerator
  • the gypsum set accelerator according to this disclosure has a better set efficiency [[,]] and a better humidity resistance. This gypsum set accelerator generates less of a buildup in a grinding mill in comparison to the HRA or freshly ground landplaster.
  • calcium sulfate dihydrate may be sourced as gypsum and/or obtained by hydration of calcium sulfate hemihydrate.
  • calcium sulfate dihydrate may be sourced from scrap gypsum wallboard.
  • Suitable gypsum includes natural ore and/or synthetic gypsum.
  • natural gypsum can be also referred to as landplaster.
  • Mined gypsum (landplaster) is composed mostly of calcium sulfate dihydrate, preferably 80% or more by weight calcium sulfate dihydrate and more preferably, about 90% to 95% by weight calcium sulfate dihydrate, and may also contain impurities and inert materials which are typically found in natural gypsum ore.
  • One preferred source for calcium sulfate dihydrate in the gypsum set accelerator according to this disclosure includes mined gypsum, such as high-grade landplaster, which is 80 or more wt% calcium sulfate dihydrate.
  • the gypsum set accelerator according to this disclosure may contain one or more polycarboxylic ethers (PCEs) and/or sulfonated melamine polycondensates (SMPs).
  • PCEs polycarboxylic ethers
  • SMPs sulfonated melamine polycondensates
  • PCEs are compounds which are known in the art as dispersants for water-based gypsum slurries in high strength flooring compositions, as disclosed in U.S. Patent 7,504,165, the entire disclosure of which is herein incorporated by reference.
  • PCE dispersants in the cited art can be either in dry or liquid form, only dry PCEs are suitable in the gypsum set accelerators according to this disclosure. Furthermore, in the cited art, PCE dispersants are used for improving dispersion of calcined gypsum in water. To the contrary, in the gypsum set accelerators according to this disclosure, a polycarboxylic ether is used as a grinding aid that prevents aging of a dry-milled gypsum set accelerator.
  • Suitable PCE grinding aid compounds include, but are not limited to, those described in WO 2006/133933, the entire disclosure of which is herein incorporated by reference. These are co-polymers containing polycarboxylate repeating units which may be derived from an olefinically unsaturated monocarboxylic acid comonomer, an ester or a salt thereof and/or an olefinically unsaturated sulfonic acid comonomer or a salt thereof.
  • a first polycarboxylate repeating unit may be preferably derived from acrylic acid, methacrylic acid, cratonic acid, isocrotonic acid, allylsulfonic acid, vinylsulfonic acid and/or suitable salts thereof and alkyl or hydroxyalkyl esters thereof.
  • a second polycarboxylate repeating unit may be derived from a monomer component that is preferably a vinyl or allyl group having a polyether residue, as described in WO 2011028817, the entire disclosure of which is herein incorporated by reference.
  • Suitable PCE grinding aid compounds according to this disclosure may further include, but are not limited to, co-polymers composed of at least the following 3 repeating units: a polyether repeating unit, an acrylic acid-type repeating unit and a maleic acid-type repeating unit.
  • co-polymers have a molecular weight of from about 20,000 to about 80,000 Daltons. More preferably, co-polymers may have a molecular weight from about 30,000 to about 50,000 Daltons.
  • the repeating units can be present in the co-polymer in any order, including random arrangement along the polymer backbone.
  • Suitable PCE copolymers include those described in U.S. Patent 6,777,517, the entire disclosure of which is herein incorporated by reference.
  • the first repeating unit may be a monocarboxylic residue, preferably an acrylic acid-type unit or its derivative, shown in Formula (I) below:
  • R 1 is a hydrogen atom or an aliphatic hydrocarbon radical having 1 to
  • the third repeating unit may be a maleic acid-type repeating unit or its ester, as shown in Formula (HL).
  • R 4 is a hydrogen or an aliphatic hydrocarbon radical having from 1 to 5 carbon atoms
  • calcium sulfate dihydrate is mixed with the PCE and/or SMP in a weight ratio in the range from 0.1 to 5 parts by weight of the PCE/SMP per 100 parts by weight of calcium sulfate dihydrate, and more preferably in the range from 1 to 2 pails by weight of the PCE/SMP per 100 parts by weight of calcium sulfate dihydrate.
  • gypsum is supplied as particles with a median particle size in the range from about 100 microns to about 250 microns, as determined by a laser scattering analysis.
  • a ball mill may be a hollow cylindrical chamber rotating about its axis.
  • the axis of the ball mill may be either horizontal or at an angle to the horizontal axis.
  • the ball mill is partially filled with balls which act as the grinding media.
  • the grinding balls may be composed of any suitable material, including, but not limited to, one or more metals and/or one or more ceramics.
  • the grinding balls comprise or consist essentially of stainless steel.
  • a size and density of the grinding balls determine, at least in part, the median particle size of the produced gypsum set accelerator.
  • the grinding balls may have an average diameter in the range from about 10 mm to about 50 mm.
  • a density may be in the range from about 2 g/cm 3 to about 6 g/cm 3 or more.
  • the gypsum set accelerator may contain ground particles with the particle size distribution with a median particle size in the range from about 10 pm to about 80 pm, and more preferably from about 20 pm to about 60 pm.
  • the mill chamber may be water-cooled and/or air-conditioned in order to prevent over-heating of the co-grinding mixture, and/or the chamber may be vented in order to remove moisture from the mill.
  • a de-humidifier can be used as well in order to remove humidity from the mill chamber.
  • Grinding methods according to this disclosure may be performed either continuously or in a batch process.
  • the co-grinding is performed at a temperature in the range that does not exceed 160 °F, e.g., in the range from about 60 °F to about 160 °F, or more preferably, in the range from about 68 °F to about 100 °F.
  • one of the technical advantages of the present gypsum set accelerator is that it can be satisfactory coground without substantially diminishing its efficiency at temperatures higher than those suitable for co-grinding HRA.
  • Another technical advantage of the gypsum set accelerator according to this disclosure is that it is less susceptible to decreasing its efficiency if it is coground or stored under humid conditions, e.g., humidity 60% or higher.
  • the gypsum set accelerator according to this disclosure may be stored under humid conditions, for example wherein the humidity is in the range from about 20% to about 80% and more preferably, at about 30% to about 50%, and still be functional as a setting accelerator.
  • the gypsum set accelerator can be prepared using dry gypsum in a batch process or in continuous process. Co-grinding can occur for any suitable period of time and in order to achieve the gypsum set accelerator with particles of desired size. In some embodiments, co-grinding may take place for a period of time from about 5 minutes to about 2 hours, and more preferably from about 5 minutes to about 1 hour, and most preferably from about 5 minutes to about 20 minutes. In some embodiments, the starting material of calcium sulfate dihydrate for co-grinding, e.g., as landplaster, may be supplied as particles with an average particle size of about 100 pm to about 200 pm which is the co-ground with the PCE and/or SMP grinding aid.
  • this disclosure relates to various gypsum products formed from a gypsum slurry prepared with the gypsum set accelerator according to this disclosure.
  • Such products may include, but are not limited to, wallboard, fiberboard, molded gypsum items and any other items which are formed from a gypsum slurry comprising at least calcined gypsum (stucco), water and any other additives as conventionally used with gypsum slurries, depending on what product is to be made from the gypsum slurry.
  • Examples of products include wallboard, fiberboards, cementitious panels, fiberglass-mat panels, floor underlayment, molded (sculptured) items, floor underlay ment and many others.
  • the gypsum set accelerator reduces the set time of an aqueous gypsum slurry more efficiently than HRA or ground landplaster.
  • the dry gypsum set accelerator may be added directly to a gypsum slurry right after it has been produced by the co-grinding method, or the gypsum set accelerator may be aged for at least an hour or more before it is used with a gypsum slurry. It has been unexpectedly discovered that as is shown by a comparative analysis in Fig.
  • the gypsum set accelerator reduces the set time (measured as a time to 50% hydration) more efficiently than HRA and furthermore, the aged gypsum set accelerator retains its efficiency better than HRA when aging even under humid conditions with humidity of 70% or higher, e.g., 90%.
  • the aged gypsum set accelerator means that prior to its use, the gypsum set accelerator according to this disclosure was stored for a period of time, e.g., for minutes, hours or even days.
  • the storage may be under any temperature and humidity, preferably as it typically can be found at a manufacturing plant.
  • a temperature may be in the range from about 10 °C to 25 °C, depending on a season.
  • Humidity may depend on a location and season. For example, it is typically more humid in Florida, USA than in California, USA during the summertime.
  • Some storage conditions may include a humidity in the range from about 20 % to about 90 %, and more commonly from about 30% to about 80%.
  • the gypsum set accelerator can be added to a gypsum slurry in any amount sufficient for obtaining the desired set time of a gypsum slurry.
  • Preferred setting times include at least 50% hydration of the gypsum slurry within 20 minutes and more preferably within 10 minutes or even 5 minutes.
  • the gypsum set accelerator may be used in an amount from about 0.1 wt% to about 5 wt% of the gypsum set accelerator, preferably from about 0.1 wt% to about 1 wt% of the gypsum set accelerator, measured as a wt% from stucco weight, e.g., from about 0.1 g to about 5 g of the gypsum set accelerator per 100 grams of stucco.
  • the gypsum set accelerator can be added to the gypsum slurry right after the gypsum set accelerator was produced by co-grounding (referred in this disclosure as a freshly co-ground set accelerator), or the gypsum set accelerator can be aged before it is added to a gypsum slurry. Being able to use an aged gypsum set accelerator is one of the technical advantages of the present gypsum set accelerator as it saves time, energy and reduces manufacturing costs.
  • the gypsum set accelerator according to this disclosure can be used with any water-based gypsum slurry.
  • gypsum slurries include, but are not limited to, gypsum slurries with a water/stucco ratio in the range from about 0.4 to about 1.5.
  • a gypsum slurry according to this disclosure may comprise one or more additives conventionally used in gypsum slurry formulations.
  • additives include binders, fibers, set accelerators, set retarders, dehydration inhibitors, adhesives, bulking agents, dispersants, thickeners, bactericides, fungicides, pH adjusters, leveling or non-leveling agents, water repellants, colorants, aqueous foams or any combination thereof.
  • a gypsum slurry may be formulated with one or more starches and/or a polymeric binder.
  • starch may include raw starch, hydroxyethylated starch, acid-modified starch, pregelatinized starch or any combination thereof.
  • starch may include pregelatinized starch which can be obtained by cooking and gelatinizing raw starch in water, for example at a temperature of about 185 °F, or higher.
  • a pregelatinized starch can be added to the gypsum slurry in a dry form and/or in a pre-dispersed liquid form.
  • Commercially available pregelatinized starches include com flour starch. Suitable starches may also include acid-modified starch, e.g., acid- modified corn starch and/or hydroxyethylated starch.
  • Suitable non-gelatinized starches may include commercially available wheat starch.
  • the gypsum slurries and gypsum cores of this disclosure may comprise from 0.3% to 5% of starch, preferably from about 0.5% to about 2% of starch by weight of calcined gypsum.
  • the gypsum cores and gypsum slurries according to this disclosure may comprise fibers.
  • fibers may include mineral wool fibers, glass fibers, carbon fibers, cellulose fibers or any combination thereof. Some preferred embodiments include those in which glass fibers, preferably E-glass fibers are used. Typically, suitable glass fibers may have an average length in the range from 0.5 to 0.76 inches and a diameter of about 11 to about 17 microns.
  • the gypsum slurries and gypsum cores of this disclosure may comprise from about 0.1% to about 2% of fibers by weight of calcined gypsum, preferably from about 0.5% to about 1% of fibers by weight of calcined gypsum.
  • the gypsum slurries may comprise calcium carbonate, mica, one or more clays, perlite, vermiculite, cement, fly ash, glass microspheres and/or other components typically used for improving one or more technical features of a gypsum-containing product.
  • These additives may be used in any suitable amounts, for example from about 0.1 wt% to about 70 wt% by weight of calcined gypsum in the gypsum slurry, depending on the additive and its conventional amounts in a gypsum slurry.
  • the gypsum cores and gypsum slurries according to this disclosure may comprise one or more of phosphate compounds which are used for increasing gypsum core strength, especially while a gypsum panel is still setting in order to improve wet (green) strength and sag resistance of the gypsum panel.
  • Suitable phosphate compounds include cyclic polyphosphates, condensed phosphoric acids, and monobasic salts or monovalent ions of orthophosphates.
  • Particularly preferred phosphate compounds include, but are not limited to, trimetaphosphate salts and tetrametaphosphate salts.
  • Particularly preferred phosphate compounds include sodium trimetaphosphate (“STMP”), potassium trimetaphosphate, ammonium trimetaphosphate, sodium hexametaphosphate, tetrapotassium tripolyphosphate, ammonium polyphosphate, aluminum trimetaphosphate or any combination thereof.
  • STMP sodium trimetaphosphate
  • potassium trimetaphosphate potassium trimetaphosphate
  • ammonium trimetaphosphate sodium hexametaphosphate
  • tetrapotassium tripolyphosphate ammonium polyphosphate
  • aluminum trimetaphosphate or any combination thereof The gypsum slurries and gypsum cores of this disclosure may comprise from about 0.05% to about 1% of one or more phosphate compounds by weight of calcined gypsum, preferably from about 0.1% to about 1% of one or more phosphate compound by weight of calcined gypsum.
  • the gypsum cores and gypsum slurries according to this disclosure may comprise one or more dispersants.
  • Suitable dispersants include naphthalensulfonates and derivatives, including sodium and/or calcium naphthalenesulfonate.
  • Other suitable dispersants include polycarboxylate dispersants and in particular, polycarboxylic ethers, including those described in U.S. patents 5,798,425, 6,777,517 and 7,767,019.
  • Some gypsum slurries may also comprise one or more lignosulfonates.
  • the gypsum slurries of this disclosure may comprise from about 0.05% to about 2% of one or more dispersants by weight of calcined gypsum, preferably from about 0.1% to about 1% of one or more dispersants by weight of calcined gypsum.
  • Suitable set retarding agents delay a hydration reaction of calcined gypsum.
  • Such set retarding agents may include, but are not limited to, commercially available protein retarder SUMA, diethylenetriamine pentaacetic acid (DTPA), tartaric acid, citric acid, maleic acid or salts thereof, including in particular sodium citrate and/or potassium bitartrate (cream of tartar), or any combination thereof.
  • a set retarding agent can be used in a small amount, for example in an amount in the range from about 0.01% to about 1.5% by weight of calcined gypsum, preferably in an amount in the range from about 0.05% to about 0.5% by weight of calcined gypsum in the gypsum slurry.
  • a gypsum slurry may be blended with foam.
  • a gypsum slurry may be mixed with a foaming agent supplied as a foam from a foam generator, as for example was described in U.S. Patents 5,643,510 and 5,683,635, the disclosures of which are incorporated by reference.
  • Gypsum slurries mixed with a foam may produce a gypsum core comprising air voids.
  • Some gypsum cores according to this disclosure may contain air voids.
  • Some gypsum cores according to this disclosure may contain air voids with a diameter in the range from about 75 micrometers to about 300 micrometers.
  • a diameter of voids on average, an average number of voids per a cubic foot of the gypsum core and the distribution of the voids through the thickness of the gypsum core can be adjusted as may be needed for maintaining the targeted gypsum core density and strength by adjusting a blending ratio of a stable foaming agent comprising an alkyl chain containing between 8 and 12 carbons and an ethoxy group having a length of 1 to 4 units (stable soap) to an unstable foaming agent comprising unethoxylated soap with an alkyl chain length of 6 to 16 carbon units (unstable soap).
  • suitable gypsum cores with air voids can be made without co-blending stable and unstable foaming agents and/or only one type of the foaming agent, e.g., stable soap, can be used.
  • Suitable foaming agents may comprise stable soap, unstable soap, or any combination hereof.
  • foaming agents comprising sodium dodecyl sulfate, magnesium dodecyl sulfate, ammonium dodecyl sulfate, potassium dodecyl sulfate, sodium decyl sulfate, alkoxylated alkyl sulfate surfactants, sodium laureth sulfate, potassium laureth sulfate, magnesium laureth sulfate, ammonium laureth sulfate, or any mixtures thereof.
  • foaming agents surfactants, soaps
  • foaming agents comprising sodium dodecyl sulfate, magnesium dodecyl sulfate, ammonium dodecyl sulfate, potassium dodecyl sulfate, sodium decyl sulfate, alkoxylated alkyl sulfate surfactants, sodium laureth sulfate, potassium laureth sulfate, magnesium laureth sul
  • a foaming agent or any blend of foaming agents may be used in any suitable amount to produce a gypsum core with a desired density and strength. In some embodiments, from about 0.01% to about 0.5% of a foaming agent can be used by weight of calcined gypsum in the gypsum slurry.
  • a gypsum slurry may comprise one or more water-repellent agents.
  • agents may include siloxane.
  • a polymerizable siloxane preferably as an emulsion which may comprise an emulsifying agent, may be added to a gypsum slurry.
  • a catalyst can be also added to the gypsum slurry. Suitable siloxane formulations and catalysts such as magnesium oxide, Class C fly ash, dead-burned magnesium oxide as disclosed in U.S. patents 7,892,472 and 7,803,226, the entire disclosures of which are herein incorporated by reference.
  • Preferred siloxanes include a fluid polymerizable linear siloxane comprising a repeating unit with the general formula FUSiO. wherein each of the two Rs independently represents a saturate or unsaturated mono-valent hydrocarbon radical or hydrogen.
  • siloxane is a hydrogen-modified siloxane.
  • a siloxane is an alkyl hydrogen siloxane, and most preferably, methyl hydrogen siloxane.
  • a gypsum slurry may comprise siloxane in an amount from about 0.3% to about 2% by weight of calcined gypsum.
  • a 50% hydration test which may be referred in this disclosure as the Temperature Rise Set (TRS) test.
  • TRS Temperature Rise Set
  • a gypsum slurry is formulated with stucco, water, the gypsum set accelerator according to this disclosure, or a control gypsum set accelerator, and optionally with one or more additives.
  • the gypsum slurry is then poured into a cup which is then placed into an insulated styrofoam container in order to minimize heat transfer to the environment.
  • a temperature probe is placed into the middle of the gypsum slurry, and the temperature is recorded every 5 seconds.
  • the setting reaction is exothermic, and its temperature rises exponentially as the reaction proceeds and the gypsum slurry sets. Eventually, the reaction reaches its maximum temperature at which the reaction curve plateaus. A time to 50% hydration is determined as the time needed to reach a half-way between the minimum temperature at the beginning of the TRS test and the maximum temperature recorded for the setting reaction during the TRS test, as can be seen in Fig. 2.
  • a gypsum slurry made with the set accelerator according to this disclosure reaches a 50% hydration time sooner than a gypsum slurry prepared with HRA or landplaster.
  • this may result in needing less time before a gypsum-containing product is solid enough to be cut to a size and/or handled.
  • This may provide significant manufacturing savings in part because a forming panel is kept on conveyor for a shorter period of time before the panel is firm enough to be cut and moved to a kiln.
  • a manufacturing conveyer can be operated at a higher speed with more panels being made per an hour during which the conveyor is in operation. This improves manufacturing efficiency and provides electricity and cost savings per each panel being made on the conveyor, transforming a manufacturing process into being more environmentally friendly.
  • Fig. 1 reports a shorter 50% hydration time for the set accelerator according to this disclosure in comparison to HRA or landplaster.
  • Fig. 2 is a comparative analysis for different gypsum set accelerators as follows: a setting reaction for a calcined gypsum slurry prepared with the gypsum set accelerator according to this disclosure (curve I), with an HRA (curve II); or ground landplaster (curve III).
  • the set accelerator according to this disclosure or control set accelerators were produced by grinding in a ball mill at 160 °F. The set accelerators were then used in a 50% hydration test (“the TRS” test).
  • the TRS 50% hydration test
  • this disclosure relates to methods for manufacturing gypsum-containing products.
  • examples of such products include wallboard, fiberboards, cementitious panels, fiberglass-mat panels, floor underlayment, molded (sculptured) items, floor underlayment and many others.
  • Preferred gypsum-containing products according to this disclosure include gypsum panels which can be manufactured on a conveyor. Some gypsum panels may include those in which a gypsum core is sandwiched between two cover sheets. Suitable cover sheets include paper cover sheets and fiberglass mats among others. Preferred gypsum panels include wallboard wherein a gypsum core is sandwiched between two paper cover sheets.
  • the method can be performed with a manufacturing assembly, generally 10, which comprises a moving conveyor (12).
  • a first cover sheet (14) which may be referred to as the face cover sheet is fed from a first roll (16) onto a wet portion (11) of the moving conveyor (12).
  • cover sheets are preferably paper cover sheets.
  • Dry and wet components (13), including calcined gypsum, water, the gypsum set accelerator, and other additives, if used, are fed into a gypsum slurry mixer (18) wherein the components (13) are mixed with agitation into a gypsum slurry.
  • a gypsum slurry mixer (18) wherein the components (13) are mixed with agitation into a gypsum slurry.
  • At least some of dry components, e.g., the gypsum set accelerator and calcined gypsum may be premixed before these dry components are mixed with water and other liquid components.
  • the gypsum slurry mixer (18) may be in communication with a ball mill (20) through a conduit (not shown) such that a freshly co-ground gypsum set accelerator (22) may be released from the ball mill (20) into the gypsum slurry mixer (18). While the gypsum set accelerator (22) may be used as freshly ground in some embodiments, the gypsum set accelerator (22) can be aged before it is added to a gypsum slurry.
  • the gypsum slurry mixer (18) may include a discharge conduit (not shown) through which a gypsum slurry (26) is released from the gypsum slurry mixer (18) onto the first cover sheet (14) moving on the wet portion (11) of the conveyor (12).
  • the discharged gypsum slurry (26) is spread over the first cover sheet (14) and is covered with a second cover sheet (28) which can be referred to as the back cover sheet, fed from a roll (30), forming a sandwich structure (ribbon panel precursor, 32) that continues moving on the conveyor (12) toward a forming station (34) of the conveyor (12), wherein the panel precursor (32) is formed into a desired thickness and continues moving on the conveyor (12) to a knife section (34) of the conveyor (12) wherein the panel precursor (32) is cut into gypsum panels (36) which can be now moved to a kiln (38) wherein the gypsum panels (36) are dried at an elevated temperature, e.g., in the range from about 110 °F to about 450 °F.
  • an elevated temperature e.g., in the range from about 110 °F to about 450 °F.
  • the gypsum set accelerator according to this disclosure decreases a 50% hydration time of a gypsum slurry with a technical advantage of permitting for the ribbon precursor (32) being ready to be cut into gypsum panels (36) sooner and therefore, the ribbon panel precursor (32) may reach the knife section (34) of the conveyor in a shorter period of time. This manufacturing process becomes more efficient because a shorter time may be needed on a conveyor before a gypsum panel (36) can be handled and cut.
  • a gypsum slurry was prepared by mixing together 200g stucco, 200g water and 1g of one of the two accelerators: MELMENT F17G (a sulphonated polycondensation product based on melamine, available from BASF corporation, NJ, USA) or MELFLUX 426 IF (a poly carboxy late ether available from BASF corporation, NJ, USA).
  • MELMENT F17G a sulphonated polycondensation product based on melamine, available from BASF corporation, NJ, USA
  • MELFLUX 426 IF a poly carboxy late ether available from BASF corporation, NJ, USA
  • a first control gypsum slurry was prepared by mixing together 200g stucco, 200g water and 1g of landplaster ground without a grinding aid.
  • a second control gypsum slurry was prepared by mixing together 200g stucco, 200g water and 1g of HRA which was prepared by co-grinding landplaster with dextrose (5% dextrose and 95% landplaster).
  • Gypsum slurries were prepared as described in Example 2. 200 grams of each gypsum slurry was then poured in a cup and a temperature probe was inserted into the gypsum slurry. The temperature probe measured a temperature of the setting gypsum slurry by the predetermined intervals, e.g., every several seconds. These temperature measurements were transmitted to a computer, wherein a software program calculated a time from the initial temperature measurement to the final temperature measurement wherein there was no further increase in temperature detected, and then calculated a 50% hydration time. Results of these measurements are shown in Figures 1 and 2.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

Abstract

L'invention concerne un accélérateur de prise de gypse, l'accélérateur de prise de gypse étant un mélange broyé à sec comprenant du sulfate de calcium dihydraté co-broyé avec un ou plusieurs des composants suivants : un éther polycarboxylique (PCE) et/ou un produit de polycondensation de mélamine sulfonée (SMP) ; des bouillies de gypse formulées avec l'accélérateur de prise de gypse. L'invention concerne également des procédés pour la production de l'accélérateur de prise de gypse et la fabrication de produits de gypse avec l'accélérateur de prise de gypse.
EP23723725.0A 2022-04-20 2023-04-14 Accélérateur de prise de gypse Pending EP4511342A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US202263332753P 2022-04-20 2022-04-20
US17/978,406 US20230339811A1 (en) 2022-04-20 2022-11-01 Gypsum set accelerator
PCT/US2023/018652 WO2023205049A1 (fr) 2022-04-20 2023-04-14 Accélérateur de prise de gypse

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CA (1) CA3248004A1 (fr)
IL (1) IL316384A (fr)
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FR3166631A1 (fr) 2024-09-20 2026-03-27 Saint-Gobain Placo Procédé de préparation d’hémihydrate alpha de sulfate de calcium.

Family Cites Families (19)

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Publication number Priority date Publication date Assignee Title
US2078199A (en) 1936-10-02 1937-04-20 United States Gypsum Co Heatproofed set-stabilized gypsum plaster
US3573947A (en) 1968-08-19 1971-04-06 United States Gypsum Co Accelerator for gypsum plaster
CA2158820C (fr) 1994-09-23 2004-11-23 Steven W. Sucech Production de placoplatre mousse
DE19513126A1 (de) 1995-04-07 1996-10-10 Sueddeutsche Kalkstickstoff Copolymere auf Basis von Oxyalkylenglykol-Alkenylethern und ungesättigten Dicarbonsäure-Derivaten
US5683635A (en) 1995-12-22 1997-11-04 United States Gypsum Company Method for preparing uniformly foamed gypsum product with less foam agitation
DE19926611A1 (de) 1999-06-11 2000-12-14 Sueddeutsche Kalkstickstoff Copolymere auf Basis von ungesättigten Mono- oder Dicarbonsäure-Derivaten und Oxyalkylenglykol-Alkenylethern, Verfahren zu deren Herstellung und ihre Verwendung
US6409823B1 (en) 1999-12-28 2002-06-25 United States Gypsum Company Hydration enhancing additives
US6379458B1 (en) 2000-02-11 2002-04-30 United States Gypsum Company Efficient set accelerator for plaster
EP1379479B1 (fr) 2001-04-03 2010-01-27 Walker Industries Holdings Limited Formulations contenant du polyvinyl alcool et du polycondensat de melamine sulfonee destinees a etre utilisees dans des pates de platre
US7892472B2 (en) 2004-08-12 2011-02-22 United States Gypsum Company Method of making water-resistant gypsum-based article
US20060278127A1 (en) 2005-06-14 2006-12-14 United States Gypsum Company Gypsum products utilizing a two-repeating unit dispersant and a method for making them
DE102006027035A1 (de) 2005-06-14 2007-01-11 Basf Construction Polymers Gmbh Polyether-haltiges Copolymer
US7504165B2 (en) 2005-06-14 2009-03-17 United States Gypsum Company High strength flooring compositions
US7803226B2 (en) 2005-07-29 2010-09-28 United States Gypsum Company Siloxane polymerization in wallboard
US7819971B2 (en) * 2006-12-29 2010-10-26 United States Gypsum Company Method of using landplaster as a wallboard filler
US20110054081A1 (en) 2009-09-02 2011-03-03 Frank Dierschke Formulation and its use
EP2607332A1 (fr) * 2011-12-19 2013-06-26 Sika Technology AG Accélérateur de prise pour liant à base de sulfate de calcium
US10737979B2 (en) 2017-04-20 2020-08-11 United States Gypsum Company Gypsum set accelerator and method of preparing same
US11834374B2 (en) 2018-04-19 2023-12-05 United States Gypsum Company Accelerator comprising starch, and related board, slurries, and methods

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IL316384A (en) 2024-12-01
MX2024011754A (es) 2024-12-06

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