JP5512062B2 - Durable porous article and manufacturing process thereof - Google Patents

Description

  The present invention relates to the field of building materials, in particular acoustic panels for walls, ceilings, movable partitions, and other interior surfaces in commercial and residential buildings. These are porous materials designed for sound absorption.

  Acoustic panels for walls and ceilings provide sound absorption, aesthetics, and separate use space within the ceiling. Manufacturers strive to develop qualified acoustic ceiling panels at the lowest possible cost, which continually refines the manufacturing process to reduce energy use, material costs, and waste by. Cost reduction is important, but is inherently limited in how much this process can be simplified and in producing panels that meet acoustic, moisture and fire resistance requirements.

  Typical wallboard manufacture begins with gypsum that is mined and ground as gypsum or obtained synthetically from a flue gas desulfurization plant. In the calcination process, the powder gypsum is heated to dehydrate the gypsum to the hemihydrate. This calcined gypsum or hemihydrate is known as stucco. Fillers such as pearlite and fiberglass are added to the stucco to achieve the desired properties of the finished wallboard. Other additives include starch, which helps the core adhere to the paper surface. Delayers and accelerators may be added, thereby adjusting the reaction rate. These ingredients are combined with water and soap foam in a high speed or pin mixer. Soap foam is added to reduce the core density, but the resulting structure is not sufficiently porous to be considered acoustic. This resulting mixture is placed between two sheets of paper and the thickness is determined by a roller. After the core is fed, the board is cut longitudinally and then sent to an oven and dried.

  Current methods for making acoustic ceiling panels utilize various combinations of fibers, fillers, binders, water and surfactants that are mixed into the slurry that is processed into the panels. This process is very similar to the method used for papermaking. Examples of fibers used can include mineral fibers, fiberglass, and cellulosic materials. Mineral cotton is a lightweight, vitreous, silicon-based material that can be spun into a fiber structure similar to fiberglass and can be used. Mineral cotton enhances acoustic performance, fire resistance, and the flex resistance of acoustic panels.

  Fillers can include expanded perlite and clay. Expanded perlite reduces material density and clay enhances the fire resistance of the acoustic panel. Examples of binders used in acoustic panels can include starch, latex, and / or recycled paper products, which are combined together to create a binding system that secures all components to the structural matrix. .

  The above components, when properly combined and processed, create a porous, sound-absorbing panel suitable for use as acoustic ceiling panels and other types of construction panels. Today such panels are manufactured using a high volume process similar to papermaking.

  Traditional methods of making panels incorporating mineral cotton fibers, pearlite fillers, and cellulose binders rely on agglomeration or agglomeration of the cellulose component. The resulting aqueous cellular foam is dried to provide a stable structure where the fibers, binders and fillers congeal and bind to create the matrix. Aqueous cellular foam mixtures can contain surfactants to facilitate the inhalation of air into this mixture, but traditional methods of making depend on condensation. A typical ceiling panel material structure is shown in the 30 × photomicrograph of FIG. Perlite particles can be identified as round nodules embedded in an interconnected matrix of mineral cotton and recycled newsprint fibers.

  Current processes for manufacturing ceiling panels are complex, involve many steps, and use large amounts of water and energy. During this process, water is gradually removed from the product via a combination of draining, pressurization, and high temperature oven heating. Some drained water can be recycled, but most is treated and released into the environment.

  Different production processes and slurry processes result in panels having different acoustic and structural properties. There is a trade-off between acoustic performance and durability. A highly porous low density material may exhibit the best acoustic performance. Unfortunately, low density materials are fragile and difficult to handle and exhibit low durability, low detergency, and low tensile strength. For the purposes of this disclosure, the term “durability” refers to the compressive yield strength of the panel (which is a measure of how easily the panel material deforms under compression). Durability against finger depression is an example of good compressive yield strength. Detergency is the durability against wear due to repetitive motion back and forth of a wet scrub brush. Tensile strength refers to the ability to lift or support a panel along one edge without breaking the panel.

  Various processes and processes are used to balance the inherent trade-offs in the production of acoustic ceiling panels. For example, one common structure in a ceiling panel is a laminate that uses different layers of material, as shown in FIG. One layer 201 includes a soft, sound-absorbing material, while the other layer 202 (which faces the room) is more durable and often relatively transparent to sound. It is a structural material. The acoustic performance of the panel is largely a function of the inner layer 201, while the outer layer 202 enhances durability, cleanability and aesthetics. The outer layer 202 in FIG. 2 can be a material supplied by a third party. Usually, an adhesive bonds the outer layer 202 to the inner layer 201. Other processes involved in the manufacture of laminated panels include painting, cutting to size and packaging.

  Laminate panels provide a good balance between performance and durability. Such panels have the advantage that they may be sensitive to continuous manufacturing processes in certain processes, but additional process steps and additional materials (eg, outer layer materials and adhesives (which create a uniform panel) If needed, it is not necessary))). Furthermore, the outer layer material is typically a costly component, and the lamination process requires additional equipment, materials and human resources. While the fabrication of the acoustic material 201 component can typically be performed in a continuous manner, the lamination process is not a continuous process. As a result, laminated panels are relatively expensive to manufacture.

  A casting or molding process is also used to create a panel structure as in FIG. Casting produces a uniform material, which is very durable and has good acoustic properties. Casting materials generally have a very high density and do not require additional layers present in the laminate structure. Casting is essentially a batch process in which material is poured into a mold. The bottom of the mold is typically lined with a carrier or release agent to prevent sticking. The material is dried in a mold, the mold is removed, and the panel is subjected to a finishing process. Molded panels usually have good mechanical strength properties and show good durability, but the acoustic properties are generally not as good as laminate panels. Disadvantages for the molding process include: the requirement to continuously move the mold through the process, where smaller panels result from mold size limitations; the added step requirement of panel removal from the mold; and Higher material cost per panel due to increased panel density.

  Another common method of making a panel having the structure shown in FIG. 1 is to extrude the slurry onto a wire belt, which allows water to drain from the slurry. Other process steps include molding, drying, and surface formation or sanding so that the panel creates the desired texture in a substantially continuous process to create the acoustical absorbing layer. Process steps such as embossing or drilling small holes in the material further enhance the acoustic absorption of the panel. Disadvantages include higher energy costs in drying and wastewater treatment.

Problems to be solved by the invention

  With the above problems in mind, there is a need to create low density materials for use in ceilings and other structural panels that have good acoustic performance but maintain the structural durability of the material.

  In addition, there is a need to make panels with high deflection resistance, improved durability, high noise reduction rate (NRC) and high acoustic transmission rate (STC).

  A common way to make panels with high STC is to apply a backing material such as foil or organic coating to the back side of the acoustic panel. The application of the backing material imparts additional processing steps and costs for the finished product.

  In addition, there is a need to create a panel that does not require additional additives to enhance fire resistance and to create a non-uniform panel having a hard, high density surface on at least one side.

Means for solving the problem

  The present invention provides a sound-absorbing porous panel that is about 53 wt.% To about 68 wt.% Cement, about 17 wt.% To about 48 wt.% Water, about 0.0. A hardened aqueous foam cementitious material comprising from 05 wt% to about 5 wt% fiber and from about 0.01 wt% to about 10 wt% surfactant; and from about 75 vol% to about 95 vol% of the material Comprising pores distributed in the curable material.

  In a preferred embodiment, the cured aqueous foamed cementitious material is about 54 wt% to about 63 wt% cement, about 32 wt% to about 44 wt% water, about 0.1 wt% on a wet basis. % To about 3% by weight fiber, and about 0.5% to about 5% by weight surfactant.

  In a preferred embodiment, the expanded cementitious material also includes from about 1% to about 10% by weight filler.

  In a preferred embodiment, the filler is calcium silicate.

  In a preferred embodiment, the calcium silicate is wollastonite.

  In a preferred embodiment, the cement is selected from the group consisting of gypsum cement, Portland cement, hydrogen oxalate cement, slag cement, fly ash cement, calcium alumina cement, and mixtures thereof.

  In a preferred embodiment, the gypsum cement is selected from the group consisting of calcium sulfate α hemihydrate and calcium sulfate β hemihydrate.

  In a preferred embodiment, the gypsum cement is selected from the group consisting of synthetic calcium sulfate β hemihydrate and chemically modified calcium sulfate β hemihydrate.

  In a preferred embodiment, the surfactant is selected from the group consisting of zwitterionic, anionic, and nonionic moieties.

  In a preferred embodiment, the surfactant further comprises a moiety selected from the group consisting of hydrophobic moieties comprising 8-20 carbons.

  In a preferred embodiment, the surfactant is selected from the group consisting of betaine, sultaine, propionate, sulfate, sulfosuccinate, and amine oxide.

  In a preferred embodiment, the surfactant is cocamidopropyl betaine, cocamidopropyl hydroxysultein, cocoamphopropionate, cocamidopropylamine oxide, cocamamine oxide, lauramine oxide, myristamine oxide and oleamine. Selected from the group consisting of amine oxides.

  In a preferred embodiment, the surfactant comprises an ethoxylated alkylphenol.

  In a preferred embodiment, it further comprises a high density coating formed adjacent to the surface of the panel and constituting less than 2% of the total thickness of the panel.

  In a preferred embodiment, it further comprises a high density coating formed on both sides of the panel and constituting less than 2% of the total thickness of the panel.

In a preferred embodiment, the panel has a density between about 10 lbs / ft ³ and about 40 lbs / ft ³ .

In a preferred embodiment, the panel has a density between about 15 lbs / ft ³ and about 35 lbs / ft ³ .

In a preferred embodiment, the panel has a density between about 20 lbs / ft ³ and about 30 lbs / ft ³ .

  In a preferred embodiment, the average diameter of the pores is between about 1.5 mm and about 50 μm.

In a preferred embodiment, the pores have an average diameter of about 40 μm to about 200 μm,
And it opens with respect to the other pore which produces the path | route which passes the said cementitious material, and, thereby, a sound is absorbed efficiently.

  In a preferred embodiment, the fibers are about 0.25 inches to about 0.75 inches long and have a diameter of about 0.0005 inches to about 0.007 inches.

  In a preferred embodiment, the fiber is a synthetic organic fiber selected from the group consisting of polyester, polyamide, and polyolefin.

  In a preferred embodiment, the polyester fiber is a polyethylene terephthalate fiber.

  In a preferred embodiment, the fibers are crimped.

  In a preferred embodiment, the panel is an acoustic ceiling tile.

  In a preferred embodiment, the panel has a noise reduction rate of at least 0.5.

  In a preferred embodiment, the panel has a noise reduction rate of at least 0.7.

  In a preferred embodiment, the acoustic transmission rate range is between about 30 and about 40.

  In a preferred embodiment, the cured foamed cementitious material is about 56% to about 61% by weight cement, about 32% to about 42% water, about 0.28% by weight on a wet basis. -About 1.3 wt% fiber, and about 0.7 wt% to about 2 wt% surfactant.

  The present invention provides a process for producing a sound-absorbing porous panel, the process comprising: about 53 wt.% To about 68 wt.% Cement, about 17 wt.% To about 48 wt.% Water, about 0 wt. Foaming a foam slurry comprising 0.05% to about 5% fiber by weight and about 0.01% to about 10% surfactant by weight; and drying the foamed foam slurry Process.

  In a preferred embodiment, the slurry further comprises about 1 wt% to about 10 wt% filler.

  In a preferred embodiment, the filler is calcium silicate.

  In a preferred embodiment, the cement is a gypsum cement.

  In a preferred embodiment, the method further includes the step of dry mixing the cement, filler, and fiber to form a dry mixture.

  In a preferred embodiment, the method further includes a step of producing a diluted surfactant solution by mixing the water and the surfactant in water.

  In a preferred embodiment, the dry mixture and the diluted surfactant solution are combined to form a foam slurry.

  In a preferred embodiment, the method further comprises applying an organic coating to the surface of the panel.

  In a preferred embodiment, the temperature of the diluted surfactant solution is from about 41 ° F. to about 168 ° F.

  In a preferred embodiment, the temperature of the diluted surfactant solution is from about 68 ° F. to about 92 ° F.

  In a preferred embodiment, the panel thickness is from about 0.25 inch to about 1 inch.

The present invention also provides a sound-absorbing porous panel comprising a cementitious material, the cementitious material comprising cement, fibers and a surfactant, wherein the cementitious material is about 10 lb / ft ³ to about 40 lb. / Ft ³ density, scratch resistance test value of at least 12, dent less than 0.12 inch, Noise Reduction Coefficient of at least 0.5, and sag test value less than 0.15 inch at 90% RH. Have

In a preferred embodiment, the panel has a density of about 15 lb / ft ³ to about 35 l / ft ³ .

  In a preferred embodiment, the panel has a scratch resistance test value of at least 18.

  In a preferred embodiment, the panel has a dent of less than 0.10 inches.

  In a preferred embodiment, the panel has a noise reduction rate of at least 0.7.

  In a preferred embodiment, the panel has a sag test value of less than 0.1 inches at 90% RH.

  In a preferred embodiment, the panel can be cut with a conventional useful knife.

  In a preferred embodiment, the panel has a water content of less than 5% by weight.

  In a preferred embodiment, the panel comprises at least 90% by weight of a porous panel.

  In a preferred embodiment, the panel comprises at least 90% by weight gypsum cement and has a noise reduction rate of at least 0.5.

  In a preferred embodiment, the noise reduction rate is at least 0.6.

  In a preferred embodiment, the noise reduction rate is at least 0.7.

  In a preferred embodiment, the panel comprises at least 95% by weight gypsum cement.

In a preferred embodiment, the density of the panel is between about 10 lb / ft ³ to about 40 lb / ft ^3.

In a preferred embodiment, the density of the panel is between about 15 lb / ft ³ to about 35 lb / ft ^3.

In a preferred embodiment, the density of the panel is between about 25l / ft ³ to about 30l / ft ^3.

In a preferred embodiment, the panel has a density of between comprises at least 90 wt% of the gypsum cement, and about 10 lb / ft ³ to about 40 lb / ft ^3.

In a preferred embodiment, the density of the panel is between about 15 lb / ft ³ to about 35 lb / ft ^3.

In a preferred embodiment, the density of the panel is between about 25 lb / ft ³ to about 30 lb / ft ^3.

  The present invention also provides a sound-absorbing porous panel comprising a substantially compositionally uniform cementitious material, the compositionally uniform cementitious material comprising cement, fibers and a surfactant, the panel comprising: The surface portion adjacent to one of these opposing surfaces has a first density and the central central portion of the panel between these two opposing surfaces is Having a second density, the first density being substantially greater than the second density;

  The sound-absorbing porous panel of the present invention is composed of a cured aqueous cellular cementitious material, wherein the resulting panel is composed of at least 90% by weight cementitious material. In addition, the aqueous cellular cementitious material may comprise from about 53 wt% to about 68 wt% cement, from about 17 wt% to about 48 wt% water, from about 0.05 wt% to about 5 wt%, based on wet weight. Consists of weight percent fiber and about 0.01 weight percent to about 10 weight percent surfactant. The panel further includes pores that comprise about 75% to about 95% by volume of the panel dispersed within the curable material.

  Furthermore, the present invention includes a sound-absorbing porous panel, wherein the resulting panel is composed of at least 90% by weight cementitious material. The foamed cementitious material comprises from about 54 wt% to about 63 wt% cementum, from about 32 wt% to about 44 wt% water, from about 0.1 wt% to about 3 wt% on a wet basis. Consisting of fibers, and about 0.5% to about 5% by weight surfactant, having pores dispersed within the cured material comprising about 75% to about 95% by volume of the material.

  The present invention includes a sound-absorbing porous panel, wherein the resulting panel is composed of about 95% by weight cementitious material. Foamed cementitious material is about 56% to about 61% by weight cementum, about 32% to about 42% water, about 0.28% to about 1.3% by weight on a wet basis. Consisting of fibers, and about 0.7% to about 2% by weight of surfactant, having pores dispersed within the cured material comprising about 75% to about 95% by volume of the material.

  Furthermore, the present invention includes a process for providing a sound-absorbing porous panel. Within the process, between about 53 wt.% And about 68 wt.% Cementum, between about 17 wt.% And about 48 wt.% Water, between about 1 wt.% And about 10 wt. A foamed slurry comprising calcium acid, between about 0.05% and about 5% by weight organic synthetic fiber, and from about 0.01% to about 10% by weight surfactant comprises air in the slurry To be aerated and foamed. The aerated foamed slurry is then dried to a water content of less than about 5% by weight of water.

The present invention can also be characterized as a sound-absorbing porous panel formed from cementitious materials, fibers and surfactants. The formed panel has a density between about 10 and 40 lb / ft ³ and a dent of less than 0.12 inches. This foam panel also has 90% RH, a noise reduction rate of at least 0.5, STC between 30 and 40 (including 30 and 40), Sag test less than 0.150 inch With the results of

  These and other features of the present invention will become more apparent with reference to the following description when taken in conjunction with the accompanying drawings.

  The present invention includes foamed cementitious materials for use in forming acoustically absorbing porous panels such as ceiling panels. The uncured foamed cementitious material formulation (wet weight percent) is about 53 wt.% To about 68 wt.% Cementum; about 17 wt.% To about 48 wt.% Water; 5% fiber by weight; and from about 0.01% to about 10% surfactant by weight. The fiber can be an organic synthetic fiber, such as that formed from polyester.

  Other formulations of uncured foamed cementitious material (wet weight percent) are about 54 wt.% To about 61 wt.% Cementum; about 32 wt.% To about 44 wt.% Water; about 0.1 wt. -About 3 wt% fiber; and about 0.5 wt% to about 5 wt% surfactant. Further, the uncured foamed cementitious material (wet weight percent) is about 56 wt.% To about 61 wt.% Cementum; about 32 wt.% To about 42 wt.% Water; About 1.3% by weight fiber; and about 0.7% to about 2% by weight surfactant.

Two specific embodiments made with the present invention include the following:
Portland cement 59.8% by weight
35.7% by weight of water
Laureth disodium sulfosuccinate surfactant 0.9% by weight
Polyester fiber 0.6% by weight
Wollastonite 3.0% by weight
Gypsum 60.7% by weight
37.9% by weight of water
Polyester fiber 0.8% by weight
0.6% by weight of ethoxylated alkylphenol surfactant.
In one embodiment, the formulation may further include certain additives to increase hardness, ease of handling, and resistance to panel dent or impact damage. Examples of additives that can contribute to the total hardness of the foamed cementum generally include calcium compounds or silica typically added in an amount of from about 1% to about 10% by weight. Examples of calcium-based curing agents can include calcium oxide, calcium hydroxide, and carbonate. Silica additives can also include sodium silicate, mica, sharpened sand, and certain ash that is high in silica such as rice husk ash and fly ash. Silicate can provide a panel with a certain hardness, which is typically measured by a scratch resistance test. This scratch resistance test is used to measure the surface integrity of the foam panel and is estimated on a scale of 10-25, where higher values indicate a more scratch resistant surface.

(Scratch resistance test)
This test consists of “scratching” a “filler” gage (spring steel) stock of varying thickness over the surface or edge of a ceiling tile or panel. This measures the most advanced “filler” gauge thickness (thousandth of an inch) that does not damage the test material. The metal tongues or fingers are equally positioned in the row and each has a raised length of about 1.875 inches. The tongue thickness increases from one end of the row to the other. The tongue thickness is 10, 12, 14, 16, 18, 20, 22, and 25 mils corresponding to the corresponding increase in stiffness. This sample is placed in a holder under a set of tongues having a sample flange lower than the cutout that forms the flange. This tongue can overlap across the top edge of the sample with the bottom of the tongue at a distance of about 7/32 inches below the surface of the sample at the cutout forming the flange. This tongue is then pulled across the sample at a rate of 20 inches / minute. Thicker tangs are more easily scratched and more easily damaged at the ends than thinner tangs.

  In the present invention, this panel has a scratch resistance test value of about 12 or greater. This value is typically at least 16 when the surface of the panel is coated with an organic coating (eg, paint, etc.), and at least about 22 when two paint films are applied to the panel. It can be. Typically, this panel is on average between about 12 and 14 for an uncoated panel and between about 16 and 18 for a panel with a single paint coating.

  In addition, hardness can be measured as a function of compression resistance as described in ASTM C367. This test was modified by the use of a 1 inch ball, a force of 30-lbs, and a crosshead speed of 1/2 inch / min. In the present invention, this panel typically has a compression resistance or dent of less than 0.12 inches. In an alternative embodiment, the compression resistance can be less than 0.1 inches, and in a second alternative embodiment, the compression resistance can be less than 0.08 inches.

  The acoustic absorption by the panel is a function of both sound energy that reflects part and absorbs part. Absorption typically occurs in one of two ways, either through the panel or by converting acoustic energy into heat by the panel material. The amount of sound energy absorbed by a material is a standardized test procedure titled “Standard Test Method 90” entitled “Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Revolution Room Method 90”. Tests with STC results are measured by insertion loss as described in ASTM E 90.

  Absorptivity is expressed as the ratio of the sound energy absorbed on the panel surface to the sound energy generated on the panel surface. This ratio is called the absorption coefficient (usually written as A). As sound energy is absorbed more, this factor approaches 1.0. Thus, when A = 0, no sound energy is absorbed and all generated sound energy is reflected. Normally, when A = 1.0, all sound energy is absorbed and the generated energy is not reflected at all. The sound absorption characteristics of the material vary with frequency and sound reduction data. Sound absorption data is described as a function of the 1/3 octave frequency band from 100 Hz to 5000 Hz. Sound absorption data is often incorporated into a singular called noise reduction rate, which is obtained from an average value rounded to the nearest multiple of A at 250, 500, 1000 and 2000 Hz. The higher the NRC value, the greater the average sound absorption in this frequency range.

  The acoustically absorbent porous panel has a noise reduction rate of at least 0.5. In a further embodiment, the panel has an NRC of at least 0.6, and in a further embodiment, the panel has an NRC of at least 0.7.

  Foamed porous cement material can include almost any cement, but hydraulic cement (eg, Portland cement, sorrel cement, slag cement, fly ash cement, calcium alumina cement, calcium sulfate α Hemihydrate or calcium sulfate β hemihydrate, natural, synthetic or chemically modified calcium sulfate β hemihydrate, as well as a mixture of reference cement components above or any mixture of reference cements above) It is not limited to. For example, mixing a calcium alumina cement and a Portland cement can provide a faster setting time for a porous cementitious composition. The calcium silicate component of this material may be selected from the conventional types known as wollastonite or Orleans One.

  The fibers added to the foam cement material can be added to the strands as essentially straight fibers that are not intentionally bent. Alternatively, the fiber can be crimped, where the fiber has an added curvature, such as a zigzag structure. In addition to polyester fibers, the fiber material can include fiberglass or mineral cotton. Other fibers can also include polyolefin and polyamide materials to increase the modulus of elasticity of the resulting material.

  Surfactants for use in the present invention include, but are not limited to, amphoteric, anionic and nonionic moieties having a hydrophobic molecular moiety containing 8-20 carbons. Such surfactants can be based on coconut oils such as cocamidopropyl betaine, cocamidopropyl hydroxysultain and cocoamphopropionate. Anionic moieties include sodium salts of sulfoxal functional groups (eg, sulfur or sulfosuccinate). For example, such anionic moieties include alkylbenzene sulfonate, sodium lauryl ether sulfate, disodium cocamide diethylamine, disodium cocamide methylethylamine sulfosuccinate, disodium cocamide methylisopropylamine, sulfosuccinate, May include disodium deceth-6 sulfosuccinate, disodium dimethicone copolyol sulfosuccinate, disodium lauret sulfosuccinate, and disodium nonoxynol-10 sulfosuccinate . Nonionic surfactants include ethoxylate and amine oxide moieties such as ethoxylated alkylphenols, cocoamine oxides, rauramine oxides, myristamine oxides, oleamine oxides and cocamidopropylamine oxides. One preferred surfactant for Portland cement is disodium lauret sulfosuccinate, but the choice of optimal surfactant depends on the properties of the cement used.

  In an alternative formulation of a cementitious foam material, alpha gypsum (eg, calcium sulfate alpha hemihydrate) can be substituted for cement. When alpha gypsum is used, for foaming purposes, the desired surfactant is an ethoxylated alkylphenol having a hydrophobic molecular moiety containing 8 to 13 carbons. This nonionic surfactant produces particle suspension properties that are optimal for gypsum.

  Foam materials can be made by combining both dry and aqueous mixtures to form a foam cement material. This dry mixture can be prepared by combining cement (eg, Portland), calcium silicate, and fibers (eg, polyethylene terephthalate (PET)) in the amounts previously disclosed. The fibers can have a nominal length of about 0.25 inches to 0.75 inches, preferably about 0.5 inches, and a diameter of about 0.0005 inches to about 0.007 inches. The dry mixture components are combined in a dry mixing device and mixed until the fibers and calcium silicate are completely dispersed. The aqueous mixture is made separately and includes water and a surfactant (eg, disodium lauret sulfosuccinate). The aqueous component is mixed to make a dilute surfactant solution. Further, the aqueous components are typically mixed and aerated or foamed at a temperature of about 41 ° F. to about 168 ° F. In alternative embodiments, the dilute surfactant solution may be mixed at a temperature between about 58 ° F and about 142 ° F, or between about 68 ° F and about 92 ° F.

  The dilute surfactant solution can be combined with the dry mixture and air in a two-stage mixing process, or the dilute surfactant solution can be aerated prior to being mixed with the dry mixture. High shear stage mixing inhales air, creates a foamed composition, and also disperses the ingredients. In the next step, the low shear mixing process ensures a uniform dispersion of the fibers. These components can vary depending on the weight in the mixture. Mixing inhales air, creates a foamed cementitious slurry, and distributes it uniformly throughout. This foamed slurry is placed in a mold having the desired shape and thickness and then cured. Once cured and dried, a relatively low density cement material is formed with the fibrous component and other components fixed in a stable matrix.

  The resulting product has a hard, dense skin on its outer surface and is typically about 1% to less than about 2% of the thickness of the material formed. This hard and dense skin layer can be seen at the top of the picture in FIG. In this embodiment, this surface layer is removed from one side of the panel by sanding or other mechanical or chemical process. In another embodiment, Applicants removed the dense skin prior to curing the cementitious material. By removing the dense layer prior to curing the cementitious material, the sander finishing step is eliminated, thus reducing the dust accumulation of the sander finish. A latex paint or sealer finish coating may be applied to reduce dust formation and provide a uniform and pleasing color.

  Traditional mineral fiber panels are browned to gray in part due in part to the amount of mineral fibers and the recycled newsprint they contain. Thus, some layers of colored coatings or paints need to provide a pleasing white surface while covering a dark substrate. Scratches or other surface wear is easily noticeable due to the color contrast between the white colored surface and the black substrate. However, cementitious materials are available in white, which requires little or no coloration in the finish coating and gives a white appearance. The white color obtained from the white combination produces a transparent appearance even when the surface is scratched.

Formed resulting material produces a cementitious composition having a density of between about 10 lb / ft ³ to about 40 lb / ft ^3. In an alternative embodiment, the panel may have a density of between about 15 lb / ft ³ and between about 35 lb / ft ³ or about 20 lb / ft ³ to about 30 lb / ft ^3,. This material can be prepared as a board, or panel, and is typically about 0.25 inches to about 1.0 inches thick. Such acoustic panels are particularly suitable for use as construction panels, wall panels or ceiling panels.

  The 30 × magnification micrograph in FIG. 3 shows the interstitial characteristics of the fiber and cement matrix and the resulting structure of the material. This material includes pores ranging from a diameter of about 1.5 mm to less than about 50 μm. Most are in the range of 40 μm to 200 μm. These interstitial pores constitute about 75% to about 95% of the material volume.

  The reinforcing fibers present in the resulting composition provide tensile strength to the matrix. Throughout the structure, the reinforcing fibers pass through the crystal cement structure and through the pores created by the foaming process.

  The finished panel is shown in a dense boundary layer. This shows a photomicrograph at a magnification of 30 in FIG. This dense boundary layer is about 150 μm to 225 μm thick and is present on both sides of the panel. This, if present, contains few foam-inducing pores and is therefore about the same density as the unfoamed cementitious cement. There is also a relatively small degree of porosity in this boundary layer, formed by micron-sized gaps in the crystal matrix. However, this porosity is very low, resulting in a hard and dense surface layer.

  The high magnification diagram of 100 × magnification in FIG. 5 shows the matrix network. The pores in the composition form a complex network of small microscopic tunnels throughout the material. Also visible in this figure are pores with a width of less than 100 μm to 225 μm interconnected with larger pores in the matrix.

  In the micrograph at 300 × magnification in FIG. 6, pores as small as a few microns obtained from the gaps between the connected crystals can be seen. Individual crystalline cement particles can also be seen in this micrograph. The cement particles have a size ranging from about 1 μm, the lower limit of micrograph resolution, to a thin flat structure, from about 10 μm to about 50 μm wide, and probably less than 1 micron thick. Other pores with a width from about 200 μm to about 225 μm are also found in this matrix. Larger networks of crystals are formed around the foam cell during manufacture, creating these and larger pores in the material. Cement crystals that are bonded together as water are bonded to the crystals during curing. The chemical bonds between randomly shaped crystals retain the network of large and small crystals shown together in FIG. These crystals are randomly aligned within this connected network. It is this linkage of the crystalline structure in the cement and around the polyester fibers that provides excellent durability and strength to panels made from the material.

  One feature of this composition is how to combine very few ingredients to make a durable, soundproof, fibrous cementitious structure suitable for making construction panels. Another feature of the composition is durability in combination with high NRC and STC. Yet another feature is an architectural panel characterized by a high porosity, pore distribution across this expanded cementitious structure. About 75% to about 95% of the volume of the panel is air.

  Removing the dense boundary layer from one side by sanding or other means exposes a highly porous structural cementitious foam composition, resulting in a highly sound absorbing panel. By leaving the backside of the dense boundary layer intact, a high STC results without the need for additional backing material (eg, foil or organic coating).

  Cementitious materials are relatively resistant to moisture. This can be quantified as a value determined by a sag test. The following is a range of approximate 4-cycle sag tests for various embodiments. Each cycle consists of subjecting a 2 ft × 2 ft sample to 82% F for 17 hours and 90% RH, followed by 82% F for 6 hours to 35% RH. In one embodiment, 90% RH typically results in a sag of less than 0.15 inches. In the second embodiment, 90% RH typically results in a sag less than 0.1 inches. In a third embodiment, 90% RH typically results in a sag less than 0.05 inches.

  The hardened cementitious material may form a construction panel that includes both a high porosity and distribution of pores throughout the expanded cementitious structure having an average pore size of about 40 microns to about 200 microns. In addition, the reticulated nature of the matrix within the material is such that most pores are exposed to other pores, creating multiple passages through the material for effective sound absorption. The panel has a self-supporting matrix structure composed of cement, polyester fibers, water and surfactant. Starch or other external binding systems are not necessary to hold the ingredients together. Other such binders can be added if desired, but these inclusions are not necessary. This is because the crystal cement combined with the polymer fibers forms a strongly bonded primary structure of the formed panel.

  While embodiments have been illustrated and described above, it will be appreciated that changes may be made in the features and components of the invention. Accordingly, although the invention has disclosed only various forms, many additions, deletions and modifications can be made herein without departing from the spirit and scope of the invention and are set forth in the following claims. It will be apparent to those skilled in the art that undue limitations should not be imposed other than. For example, the type of cement used in the formula can vary based on the desired properties of the material. Further, the fiber type, length and diameter can vary based on the strength requirements of the final product comprised of the panels.

  A sound-absorbing porous panel formed from a cured aqueous foamed cement material, comprising about 53% to about 68% by weight cement, about 17% to about 48% water, about 0% A sound-absorbing porous panel consisting of .05 wt% to about 5 wt% fiber and about 0.01 wt% to about 10 wt% surfactant. The panel also has pores comprising about 75% to about 95% of the volume of material distributed within the cured material. This cement-based foamed panel provides a good acoustic effect with enhanced durability and moisture resistance.

Effect of the invention

  In accordance with the present invention, low density materials are produced for use in ceilings and other structural panels that have good acoustic performance but maintain the structural durability of the material.

  FIG. 1 is a photomicrograph (30 ×) of a mineral cotton material made according to the prior art.   FIG. 2 is a perspective schematic view of a laminate-based acoustic panel made according to the prior art.   FIG. 3 is a photomicrograph (30 ×) of a material made in accordance with the present invention.   FIG. 4 is a photomicrograph (30 ×) of a material made according to the present invention.   FIG. 5 is a photomicrograph (100 ×) of a material made in accordance with the present invention.   FIG. 6 is a photomicrograph (300 ×) of a material made in accordance with the present invention.

201 inner layer 202 outer layer

Claims (50)

Sound-absorbing porous panel, 56% to 61% by weight cement, 3% by weight
2% to 42% water, 0.28% to 1.3% fiber, and 0.7% by weight
A hardened aqueous foam cementitious material comprising ˜2% by weight of a surfactant; and pores distributed within the curable material comprising 75% to 95% by volume of the material;
The pores have an average diameter of 40 μm to 200 μm and create a path that opens to the other pores and passes through the cementitious material, whereby the sound is efficiently absorbed; And the panel has a density between 20 lb / ft ³ and 30 lb / ft ³ ,
Sound-absorbing porous panel.
The sound-absorbing porous panel according to claim 1, wherein the foamed cementitious material also contains 1 wt% to 10 wt% filler.
The sound-absorbing porous panel according to claim 2, wherein the filler is calcium silicate.
The sound-absorbing porous panel according to claim 3, wherein the calcium silicate is wollastonite.
The sound-absorbing porous panel according to claim 1, wherein the cement is selected from the group consisting of gypsum cement, Portland cement, hydrogen oxalate cement, slag cement, fly ash cement, calcium alumina cement, and mixtures thereof. .
The sound-absorbing porous panel according to claim 5, wherein the gypsum cement is selected from the group consisting of calcium sulfate α hemihydrate and calcium sulfate β hemihydrate.
The sound-absorbing porous panel according to claim 5, wherein the gypsum cement is selected from the group consisting of synthetic calcium sulfate β hemihydrate and chemically modified calcium sulfate β hemihydrate.
The sound-absorbing porous panel according to claim 1, wherein the surfactant is selected from the group consisting of zwitterionic, anionic, and nonionic moieties.
The sound-absorbing porous panel according to claim 8, wherein the surfactant further comprises a portion selected from the group consisting of a hydrophobic portion containing 8 to 20 carbons.
The sound-absorbing porous panel according to claim 8, wherein the surfactant is selected from the group consisting of betaine, sultaine, propionate, sulfate, sulfosuccinate, and amine oxide.
The surfactant is cocamidopropyl betaine, cocamidopropylhydroxysultein, cocoamphopropionate, cocamidopropylamine oxide, cocamamine oxide,
The sound-absorbing porous panel according to claim 8, selected from the group consisting of lauramine oxide, myristamine oxide and oleamine oxide.
The sound-absorbing porous panel according to claim 1, wherein the surfactant comprises an ethoxylated alkylphenol.
The sound-absorbing porous panel according to claim 1, further comprising a high-density coating formed adjacent to the surface of the panel and constituting less than 2% of the total thickness of the panel.
The sound-absorbing porous panel according to claim 13, further comprising a high-density coating formed on both sides of the panel and constituting less than 2% of the total thickness of the panel.
The sound-absorbing porous panel according to claim 1, wherein the average diameter of the pores is between 100 μm and 50 μm.
The fibers are 0.25 inches to 0.75 inches long and have a diameter of 0.000
The sound-absorbing porous panel according to claim 1, which is 5 inches to 0.007 inches.
The sound-absorbing porous panel according to claim 1, wherein the fiber is a synthetic organic fiber selected from the group consisting of polyester, polyamide, and polyolefin.
The sound-absorbing porous panel according to claim 17, wherein the polyester fiber is a polyethylene terephthalate fiber.
The sound-absorbing porous panel according to claim 1, wherein the fibers are crimped.
The sound-absorbing porous panel according to claim 1, wherein the panel is an acoustic ceiling tile.
The sound-absorbing porous panel according to claim 1, wherein the panel has a noise reduction rate of at least 0.5.
The sound-absorbing porous panel according to claim 21, wherein a noise reduction rate of the panel is at least 0.7.
The sound-absorbing porous panel according to claim 1, wherein the range of the sound transmission rate is between 30 and 40.
A process for producing a sound-absorbing porous panel according to claim 1, comprising: 56% to 61% by weight cement, 32% to 42% water, 0.28% to 1.%. Aerating a foam slurry comprising 3% by weight fibers and 0.7% to 2% by weight surfactant; and drying the aerated foam slurry.
25. The process of claim 24, wherein the slurry further comprises 1 wt% to 10 wt% filler.
26. The process of claim 25, wherein the filler is calcium silicate.
The process according to claim 24, wherein the cement is a gypsum cement.
25. The process of claim 24, further comprising dry mixing the cement, filler, and fiber to form a dry mixture.
30. The process of claim 28, further comprising the step of aqueous mixing the water and surfactant to produce a diluted surfactant solution.
30. The process of claim 29, wherein the dry mixture and the diluted surfactant solution are combined to form a foam slurry.
25. The process of claim 24, further comprising applying an organic coating to the surface of the panel.
30. The process of claim 29, wherein the temperature of the diluted surfactant solution is from 41 [deg.] F to 168 [deg.] F.
35. The process of claim 32, wherein the temperature of the diluted surfactant solution is 68 [deg.] F to 92 [deg.] F.
25. The process of claim 24, wherein the thickness of the panel is from 0.25 inch to 1 inch.
The sound-absorbing porous panel of claim 1, wherein the panel has a scratch resistance test value of at least 12, a dent of less than 0.12 inches, and a NoiseRedu of at least 0.5.
ction
A sound-absorbing porous panel having a coeffecient (sound reduction) and a sag test value of less than 0.15 inches at 90% RH.
36. The sound absorbing porous panel of claim 35, wherein the panel has a scratch resistance test value of at least 18.
36. The sound absorbing porous panel of claim 35, wherein the panel has a dent of less than 0.10 inches.
36. The sound absorbing porous panel of claim 35, wherein the panel has a noise reduction rate of at least 0.7.
36. The sound absorbing porous panel of claim 35, wherein the panel has a sag test value of less than 0.1 inches at 90% RH.
36. The sound absorbing porous panel of claim 35, wherein the panel can be cut with a knife.
36. The acoustically absorbent porous panel according to claim 35, wherein the panel has a water content of less than 5% by weight.
36. The acoustically absorbent porous panel according to claim 35, wherein the cementitious material comprises at least 90% by weight of the porous panel.
The cement comprises at least 90 wt% gypsum cement and the panel is at least 0;
. The sound-absorbing porous panel according to claim 1, having a noise reduction rate of 5. 5.
44. The acoustically absorbent porous panel according to claim 43, wherein the noise reduction rate is at least 0.6.
45. The sound-absorbing porous panel according to claim 44, wherein the noise reduction rate is at least 0.7.
44. The acoustically absorbent porous panel of claim 43, wherein the cement comprises at least 95% by weight gypsum cement.
44. The sound-absorbing porous panel according to claim 43, wherein the density of the panel is between 25 lb / ft ³ and 30 lb / ft ³ .
The sound-absorbing porous panel of claim 1, wherein the cement comprises at least 90 wt% gypsum cement.
49. The sound-absorbing porous panel according to claim 48, wherein the density of the panel is between 25 lb / ft ³ and 30 lb / ft ³ .
The sound-absorbing porous panel according to claim 1, comprising a substantially compositionally uniform cementitious material, wherein the compositionally uniform cementitious material comprises cement, fibers and a surfactant. Has two opposing surfaces, a surface portion adjacent to one of the opposing surfaces has a first density, and a central portion between the two opposing surfaces has a second density. A sound-absorbing porous panel comprising and having the first density substantially greater than the second density .

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