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WO2025057181A1 - Composition de plâtre et procédé pour sa fabrication - Google Patents

Composition de plâtre et procédé pour sa fabrication Download PDF

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Publication number
WO2025057181A1
WO2025057181A1 PCT/IN2024/051582 IN2024051582W WO2025057181A1 WO 2025057181 A1 WO2025057181 A1 WO 2025057181A1 IN 2024051582 W IN2024051582 W IN 2024051582W WO 2025057181 A1 WO2025057181 A1 WO 2025057181A1
Authority
WO
WIPO (PCT)
Prior art keywords
gypsum plaster
plaster composition
composition
gypsum
filler
Prior art date
Application number
PCT/IN2024/051582
Other languages
English (en)
Inventor
Balakrishnan S
Sneha Sruthi VIJAPURAPU
Souvik ATA
Nirmal SWAIN
Original Assignee
Saint-Gobain Placo
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
Application filed by Saint-Gobain Placo filed Critical Saint-Gobain Placo
Publication of WO2025057181A1 publication Critical patent/WO2025057181A1/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
    • 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
    • C04B2111/00482—Coating or impregnation materials

Definitions

  • the present disclosure relates in general to a gypsum plaster composition. More particularly, the present disclosure provides a gypsum plaster composition with specific additives and retarders. Such a gypsum plaster composition can be applied directly on a RCC substrate.
  • Gypsum is a common mineral composed of calcium sulfate dihydrate. It is an abundant and easily accessible mineral on the Earth’s surface, which has been extensively processed and used by humans since the Neolithic period for different decorative and construction purposes. It is widely mined and is used as a fertilizer and specifically as the main constituent in many forms of plaster, blackboard/sidewalk chalk, and dry wall etc. A massive fine-grained white or lightly tinted variety of gypsum is used for sculpture. The gypsum is used for variety of gypsum products, most used as building materials, with an example being wallboard and fiberboard sheets, for many reasons. They are easily manipulated to make continuous walls of desired shapes and sizes. They are durable, easily installed, patched, and have beneficial insulation, fire and acoustic properties. Decorative finishes, such as wallpaper or paint readily adhere to surfaces to allow for a large variety of decorating options.
  • gypsum plasters can be applied to brick walls, concrete blocks, or reinforced cement concrete (RCC) surfaces.
  • Gypsum plasters usually come in ready to mix bags, in which the powder can be extracted in a dry vessel and then mixed with water. The mixture is to be stirred for 2-3 minutes and based on desired thickness of plaster it can be applied on the wall.
  • Application is also extended to ceiling & common areas, for example, parking lots, staircase underlayment & basement.
  • plastering and finishing in hot and humid climate areas usually consists of an undercoat plaster followed by finishing with putty, primer and paint.
  • Putty is a white cement-based formulation available in dry mix powder as well as acrylic ready- to-use paste. Putty is an air-drying product with limited thickness build-up of approximately 3mm, which usually takes 3 days including curing and coating (4-6 mm not possible in one coat application).
  • the applicators are different for plastering and finishing which usually add up the labor cost by the usage of multiple applicators for every step.
  • US 2005-0241541 document discloses a gypsum plaster using high viscosity cellulose ether manufactured from raw cotton linters, and said method describes that the water repellency, sag resistance, and workability of the gypsum plaster may be improved, and the usage amount of the cellulose ether may be reduced.
  • the cellulose ether composition is used in a gypsum plaster, nonunwinding gypsum lumps are generated in water, and consequently, to eliminate the same, working time of operators increases or when applied to a wall surface or the like, uneven plaster surface occurs, lumps, and the like, and the quality of the final working result is reduced.
  • Korean Patent No. 2011-0082857 discloses a plaster additive composition for a gypsum-based finish containing cellulose ether, polyacrylamide and guar gum, and according to this method, primary taste workability is improved by including guar gum in the additive composition.
  • the secondary surface pureness work which is conducted after approximately 5 to 30 minutes after the primary fine bowel work, the retention property of the gypsum plaster is reduced and the viscosity is increased and the plaster is embedded, and hence the workability is reduced, thereby resulting in a phenomenon in which the work surface is roughened.
  • an improved cellulose ether-based thickener composition with improved properties can be used to improve thickening effect.
  • the improving cellulose ether thickener composition comprises at least one physical property improving additive which is anionic, neutral, or cationic and has thickening, adsorbing and flocculating effects, and the strong adsorbing and flocculating effects of the physical property improving additive increases the thickening effect of the thickener.
  • the main object of the present invention is to provide a gypsum plaster composition with improved adhesion on a reinforced cement concrete surface.
  • another object of the present invention is to provide a gypsum plaster composition which can be applied directly as a monolayer on a reinforced cement concrete surface.
  • Yet another object of the present invention is to provide a gypsum plaster composition which avoids the application of putty, primer, and paint.
  • yet another object of the present invention is to provide a method of manufacturing of a gypsum plaster composition, and a method of applying gypsum plaster composition on a reinforced cement concrete surface.
  • a gypsum plaster composition comprises 25 to 75 % of stucco; 25 to 75 % of filler; 0.005 to 0.1 % of retarder; 0.01 to 0.1 % of heat resistant accelerator; 0.05 to 0.5 % of modified cellulose ether; 0.05 to 3 % of re-dispersible polymer; and 0 to 1 % of coloring agent.
  • Such a gypsum plaster composition exhibits improved direct adhesion on a reinforced cement concrete surface.
  • a method of manufacturing a gypsum plaster composition comprises the steps of mixing the stucco, filler, retarder, heat resistant accelerator, modified cellulose ether, re-dispersible polymer and coloring agent until a uniform, homogeneous dry mix is formed. Further added to the dry mix is water (here 40-50wt.%), to form a lump-free consistent slurry.
  • a method of applying gypsum plaster composition on a reinforced cement concrete surface is disclosed. Said method comprises the steps of coating the pre-wetted surface of the RCC substrate with the gypsum plaster slurry. The applied coating is troweled to smoothen the coat. Further, optionally a diluted coat of less than 1 mm is applied before set within the setting time of plaster.
  • additive(s) or ‘modifier(s)’ can be used interchangeably, refers to additional components included in the base gypsum plaster composition.
  • adheresion refers to the tendency of the gypsum plaster composition to firmly cling on to the reinforced cement concrete surface.
  • reinforced cement concrete or ‘RCC’ can be used interchangeably, as known to a person of ordinary skill in the art, refers to blend of concrete that has essentially the same ingredients as conventional concrete but in different ratios, and increasingly with partial substitution of fly ash for Portland cement.
  • the RCC possesses high tensile strength.
  • paste refers to a material with high plasticity, similar in texture to clay or dough, typically used in constructions and repair as a sealant or filler.
  • wall putty is applied on walls, right after their construction is complete with bricks and sand-cement plaster, which helps in smoothing out the wall surface and making it easier to apply a coat of primer and then paint on the walls.
  • Primer refers to a precoating applied on the surface to prepare it for the subsequent process of finishing. It is a product like paint but is not a final finish, as it only protects the surface and acts as a support for a better paint adhesion.
  • the present application provides a gypsum plaster composition.
  • the gypsum plaster composition comprises 25 to 75 % of stucco; 25 to 75 % of filler; 0.005 to 0.1 % of retarder; 0.01 to 0.1 % of heat resistant accelerator; 0.05 to 0.5 % of modified cellulose ether; 0.05 to 3 % of redispersible polymer and 0 to 0.5% of coloring agent.
  • a composition has exhibited enhanced, direct adhesion on a reinforced cement concrete surface.
  • such a gypsum plaster composition also possesses faster curing or setting time, low volume loss to abrasion and enhanced coverage for the same thickness.
  • the present inventors have unexpectedly realized that the additives including modified cellulose ether and the re-dispersible polymer can be used in combination with base stucco composition, which when further applied on an RCC surface not only improved the direct adhesion but achieved undulated free coating. Further, beneficially the inventors have also realized that with the addition of the aforesaid additives, the gypsum slurry composition avoids the additional need of application of putty and / or primer. Furthermore, the gypsum slurry composition avoids the additional need of application of paint, as the case may be. In accordance with the present invention, the stucco is present in an amount ranging from 25 to 75 wt% of the composition.
  • the stucco is present in the range of 25 to 50 wt%. In a most preferred embodiment, the stucco is present in an amount of 25 - 40% by weight.
  • the stucco can have a variety of compositions, depending on the source and the application at hand.
  • the stucco is a white cementing material made by partial or complete dehydration of the mineral gypsum. It is an environmentally friendly alternative to traditional sand-cement application for internal plastering surfaces.
  • the stucco in accordance with the present invention provides excellent thermal and acoustic properties while providing superior rich and smooth finish, when used in combination with the modifiers and / or additives.
  • Gypsum plastering is also a faster application method for internal surfaces, since it does not require time consuming water curing process. While water curing process is mandatory for 20 to 21 days after sandcement plastering to reduce shrinkage cracks arising due to heat of hydration.
  • the gypsum plaster composition in accordance with the present invention cures in less than 1 hour. In some embodiments, the gypsum plaster in accordance with the present invention cures in less than 6 hours including final coat. In a most preferred embodiment of the present invention, the gypsum plaster cures in less than 45 minutes.
  • the gypsum plaster composition comprises a filler, in accordance with the present invention, ranging in an amount of 25 to 75 %. In a preferred embodiment, the filler is present in an amount of 50 to 75%.
  • the filler provides desired coverage and water retention property to gypsum.
  • the weight ratio of stucco to filler is no more than 30:70. In accordance with the present disclosure, weight of stucco is no less than 25% and weight of filler is no more than 75%.
  • the filler in accordance with the present invention has a particle size ranging from 10 to 150 microns.
  • the gypsum plaster composition in accordance with the present invention may also further comprise one or more accelerators, retarders, fluidizers, coloring agents, dispersants, foaming agents, and/or glass fibers.
  • the aforesaid agents are present in an amount of no more than 2.0 weight % of the gypsum plaster composition.
  • the aforesaid agents are present in an amount of no more than 1.0 % or no more than 0.5 % by weight of the gypsum plaster composition.
  • a person of ordinary skill in the art will use an appropriate set of the aforesaid agents for the desired gypsum slurry composition.
  • a combined cellulose ether and re-dispersible polymer in accordance with the present disclosure is in the range of 0.6 to 1.75%. In most preferred embodiment, the amount is in the range of 1 to 1.5%.
  • the retarder is present in an amount ranging from 0.005 to 0.15 % and is selected from the group consisting of organic admixtures such as tartaric acid and its salts, citric acid, phosphates, protein and any composite. In a most preferred embodiment, the retarder is present in an amount of 0.005% to 0.1% and is used to extend/ delay the setting time of gypsum by slowing the rate of crystal formation, hence, providing enough time for mixing and application of the plaster for desired substrate. In a specific embodiment, the retarder is citric acid.
  • the heat resistant accelerator is present in an amount ranging from 0.01 to 0.1 % and is selected from the group consisting of calcium sulphate dihydrate, potassium sulphate, magnesium oxide or a combination thereof.
  • the heat resistant accelerator is calcium sulphate dihydrate coated with sucrose which is present in an amount of 0.025 to 0.1%.
  • the heat resistant accelerator in every embodiment is required for providing nucleation sites for and increasing the rate of gypsum crystal growth.
  • the inventors in accordance with the present disclosure have avoided the use of paint by introducing a coloring agent in an amount ranging up to 1 %.
  • the coloring agent is present in an amount ranging from 0.1 to 1% and is selected from the group consisting of non-ionic surfactant, iron oxide yellow, pyrazol, butanamide, chromium oxide, azo and phenylene compounds. In a most preferred embodiment, the coloring agent is present in less than 0.75 wt% and is an aqueous dispersible agent.
  • the gypsum plaster composition can also be devoid of coloring agent, as preferred by the end customers. The gypsum plaster composition without coloring agent gives a white color.
  • the modified cellulose ether is present in the range of 0.05 to 0.5 % by weight of the gypsum plaster composition. In a preferred embodiment the modified cellulose ether is present in the range of 0.05 to 0.3%. In a most preferred embodiment, the modified cellulose ether is present in an amount of 0.1 to 0.25% by weight of the gypsum plaster composition.
  • the modified cellulose ether in accordance with the present invention is selected from the group consisting of hydroxypropyl methyl cellulose; hydroxyethyl methyl cellulose, starch, cellulose ether, modified cellulose ether, guar gum, dextrose, or a combination thereof. In a preferred embodiment, the modified cellulose ether is a thickener as well as a water retention agent improving the workability & viscosity of gypsum plaster.
  • the re-dispersible polymer is present in the range of 0.5 to 3% by weight of the gypsum plaster composition. In a preferred embodiment the re-dispersible polymer is present in the range of 0.5 to 2%. In a most preferred embodiment, the re-dispersible polymer is present in an amount of 0.5 to 1.5% by weight of the gypsum plaster composition.
  • the re-dispersible polymer in accordance with the present invention is selected from the group consisting of PVAc, PVA, EVA or a combination thereof. In a preferred embodiment, the re-dispersible polymer is a copolymer of EV Ac.
  • the cellulose ethers provide good water retention, prevents chalking and the re-dispersible polymers (being neutral) aids bonding with RCC substrate.
  • the re-dispersible polymer in accordance with the present invention also improves the workability and enhances the mechanical properties including tensile, flexural strength and abrasion resistance of the coated RCC substrate.
  • the adhesion strength of the coating applied onto the surface is 0.2 to 1.5 MPa. In a preferred embodiment, the adhesion strength of the coating applied onto the surface is 0.25 MPa.
  • the re-dispersible polymer has a particle size ranging from 50 to 100 microns. In a preferred embodiment, the redispersible polymer has a particle size of 60 to 80 microns. In another embodiment, the re-dispersible polymer has a density in the range of 490 -590 kg/m 3 .
  • the present invention discloses a method of applying gypsum plaster composition on a reinforced cement concrete surface.
  • the method comprises the steps of coating the already pre-wetted surface of the RCC substrate with the gypsum plaster slurry.
  • the applied coating is troweled to smoothen the coat.
  • a diluted coat of less than 1 mm is applied before set within the setting time of plaster.
  • the formed mixture of gypsum plaster is applied as a single coat layer or as a monolayer or as a dual coat on the RCC surface.
  • the formed mixture of gypsum plaster is applied as a single coat layer or as a monolayer on the RCC surface.
  • the method avoids a further application of putty, primer and paint.
  • the gypsum plaster applied on the RCC substrate, in accordance with the present invention has an adhesion strength ranging from 0.2 to 0.3 MPa.
  • the CS is tested using a standardized UTM tester or a compression tester from AIMIL Ltd.
  • the load rate is 2.9kN/s and the results are calculated in MPa.
  • the AR is tested using a standardized Abrasion tester from Elcometer.
  • the test protocol follows for 50 cycles; Speed: 65 cycles/min and failure mode are determined as no. of cycles until complete material removal. The final calculation is volume loss in cm 3 .
  • inventive and comparative coated samples were cut into two equal halves, thereafter, immersed in water up to a height of 5- 10mm. As the core encounters water, absorption of water due to capillary action results in increase in weight. This gravimetric change was noted to quantify the moisture resistance. Coefficient of water absorption has been calculated using the below formula.
  • the mean of the individual half-specimens was calculated as mean coefficient of water absorption due to capillary action (Cm) stated to the nearest 0.1 kg / (m 2 . min0.5).
  • the sample as per the inventive example 1 showed an absorption coefficient between 0.028 and 0.045 which is well below the standard limit of 0.1 kg/m 2 min° 5 ..

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)

Abstract

La présente demande concerne une composition de plâtre, comprenant 25 à 75 % de plâtre ; 25 à 75 % de charge ; 0,005 à 0,1 % de retardateur de prise ; 0,015 à 0,1 % d'accélérateur de prise résistant à la chaleur ; 0,05 à 0,5 % d'éther de cellulose modifié ; 0,05 à 3 % de polymère redispersable ; et 0 à 0,5 % d'agent colorant. Une telle composition de plâtre présente une adhérence directe améliorée sur une surface en béton armé (RCC). En outre, la demande concerne également un procédé de fabrication d'une composition de plâtre et un procédé pour son application.
PCT/IN2024/051582 2023-09-13 2024-08-30 Composition de plâtre et procédé pour sa fabrication WO2025057181A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IN202341061768 2023-09-13
IN202341061768 2023-09-13

Publications (1)

Publication Number Publication Date
WO2025057181A1 true WO2025057181A1 (fr) 2025-03-20

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004030121A1 (de) * 2004-06-22 2006-01-19 Pci Augsburg Gmbh Hydraulisch abbindender Klebemörtel
US9950954B2 (en) * 2012-07-10 2018-04-24 Sika Technology Ag Two component cement composition

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004030121A1 (de) * 2004-06-22 2006-01-19 Pci Augsburg Gmbh Hydraulisch abbindender Klebemörtel
US9950954B2 (en) * 2012-07-10 2018-04-24 Sika Technology Ag Two component cement composition

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