CONDUCTIVE PAPER FOR MANUFACTURING ELECTROACTIVE SURFACE IN CONSTRUCTION
Patent Information
- Authority / Receiving Office
- MX · MX
- Patent Type
- Patents
- Current Assignee / Owner
- UNITED STATES GYPSUM CO
- Filing Date
- 2021-10-18
- Publication Date
- 2026-06-12
Abstract
Description
CONDUCTIVE PAPER FOR MANUFACTURING ELECTROACTIVE SURFACE IN CONSTRUCTION FIELD OF INVENTION This description refers to construction products comprising an electroconductive surface, as well as methods and materials for controlling the electrical conductivity and electromagnetic shielding capability of a surface in building construction. BACKGROUND OF THE INVENTION In building construction, different types of panels are used to form interior walls, exterior walls, roofs, floors, and ceilings. A common material used in interior wall construction is paper-faced gypsum board, commonly known as wall panel. Typically, wall panel (also called drywall or plasterboard) is made by preparing a slurry comprising calcined gypsum, water, and other components. The gypsum slurry is then deposited between two sheets of paper. After setting, the gypsum slurry forms a gypsum core between the two paper facing sheets. U.S. patents such as 8,197,952, 4,853,085, and 1,769,519 relate to gypsum wall panel and methods for manufacturing them. Other building construction products include ceiling tiles, doors, fiberboard, floor tiles, and many others. QP17. Ln / ίΖΠΖ / Β / ΥΙΛΙ Ref. 327147 In some circumstances, it may be necessary to produce a building product with an electroconductive surface or to reinforce a building product with an electroconductive surface. Such products can be used as electromagnetic wave shielding, for example, when radio waves and / or a Wi-Fi connection need to be blocked. U.S. patent 5,422,174 describes an electromagnetic wave shielding building material comprising a hydraulic inorganic material and 0.6–3% by weight carbon fibers mixed with cement. U.S. patent 9,840,851 describes building construction materials, including coatings and layers embedded or encapsulated by a core, that provide sound attenuation or blocking. WO 99 / 62076 describes composite materials comprising a thin layer of electrically conductive cellulose, which has the ability to shield against electrical and high-frequency waves. U.S. patent 8,211,556 describes a gypsum building material comprising graphite and having electromagnetic shielding capabilities.U.S. Patent 7,641,764 describes a nonwoven fabric for gypsum board comprising 20 to 60% by weight of fiberglass and carbon fiber as the conductive fiber. U.S. Patent 5,496,966 describes a construction absorber that provides a surface for absorbing incident electromagnetic signals of a selected frequency range. The absorber panel includes absorbent layers that are preferably carbon fibers, iron carbonyl powder, or a ferrite material placed between an upper and a lower surface of the absorber. However, there is still a need in the field of construction products with an electroconductive surface where electroactivity can be controlled and adjusted as required. There is also a need for materials and methods by which a construction product can be reinforced with an electroconductive surface. SUMMARY OF THE INVENTION In one aspect, the present description provides a building product with an electroconductive surface, wherein the building product comprises a core with one or more surfaces covered by an electroconductive paper comprising carbon fibers, wherein the electroconductive paper is bonded to the one or more surfaces of the core. The building product may be a wall panel, a fiberboard, a ceiling tile, a floor tile, a door, a plank, a frame, or a roof tile. The building product may be a wall panel, and the electroconductive paper comprising carbon fibers is applied to at least one of the long surfaces of the wall panel. In any of the building construction products described herein, the conductive paper cladding sheet may be a multilayer paper comprising a surface layer with carbon fibers incorporated therein. Suitable carbon fibers include long carbon fibers, short carbon fibers, or any mixture thereof. In some building construction products, the paper cladding sheet is a multi-layered paper cladding sheet comprising a surface layer, and carbon fibers are incorporated into the surface layer in an amount of 2% to 40% of the total fibers per layer, and where the remainder of the fibers in the layer are cellulose fibers. In some building construction products, carbon fibers are incorporated into the paper cladding sheet in a pattern. In another aspect, the present description provides electrically conductive paper comprising a surface layer and one or more filler layers beneath the surface layer, wherein the electrically conductive paper comprises carbon fibers at least in the surface layer. In some embodiments, the electrically conductive paper may further comprise carbon fibers in the one or more filler layers beneath the surface layer. Suitable carbon fibers have a diameter in the range of 1 to 15 micrometers (μm) and a length in the range of 1 to 20 millimeters (mm). The carbon fibers can be short carbon fibers, long carbon fibers, or any combination thereof. The carbon fibers can be interwoven with cellulose fibers. Part of the electrically conductive paper may also include carbon nanotubes. In some forms of electroconductive paper, carbon fibers are incorporated in an amount of 2% to 40% by weight of total fibers per surface layer, and the remainder of the fibers in the surface layer may be cellulose fibers. In some types of conductive paper, carbon fibers may comprise 2% to 5% by weight of the total fibers per surface layer, with the remaining fibers in the surface layer being cellulose fibers. The carbon fibers may be incorporated into the surface layer in a pattern. In some conductive papers, the carbon fibers in the surface layer are oriented parallel or nearly parallel to each other. In other respects, the present description provides an electroconductive paper screen comprising one or QP17. Ln / ίZЖРZ� / Β / YΙΛΙ plus suspension media and electroconductive paper comprising a surface layer and one or more filler layers beneath the surface layer, wherein the electroconductive paper comprises carbon fibers at least in the surface layer. In another aspect, the present description provides a method for imparting an electroconductive surface to a building construction product, wherein the method comprises: a) forming a sheet of paper from a paper pulp comprising carbon fibers and / or embedding carbon fibers in the forming paper sheet in a pattern; b) dry the sheet of paper; and c) attach the sheet of paper to one or more surfaces of the building construction product. Other aspects of the present description include methods for protecting an area from electromagnetic waves, where the methods comprise enclosing the area with electroconductive paper comprising a surface layer and one or more filler layers beneath the surface layer, where the electroconductive paper comprises carbon fibers at least in the surface layer. Other aspects of the present description include methods for protecting an area from electromagnetic waves, wherein the methods comprise enclosing the area with electroconductive paper comprising a surface layer and one or QP / 7 LO / 17P7 / E / YILI plus filler layers beneath the surface layer, wherein the electroconductive paper comprises carbon fibers at least in the surface layer. Other methods include navigation methods, including indoor navigation, in which navigation is guided by detecting a signal generated by the electroconductive surface of the building construction product described herein. BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a perspective view of a building construction product comprising an electroconductive surface. Figure 2 is a cross-sectional view of an electroconductive multilayer paper comprising carbon fibers. Figure 3 is a block diagram for a manufacturing process of the electroconductive paper cladding sheet comprising carbon fibers. Figure 4 is a schematic diagram of a continuous manufacturing process for a building construction product comprising an electroconductive surface. DETAILED DESCRIPTION OF THE INVENTION In one aspect, the present description provides a building construction product comprising an electroconductive surface. As shown in Figure 1, a building construction product (10) generally comprises a core (12) covered on one surface with a paper cladding sheet (14). The paper cladding sheet (14) is electroconductive and comprises carbon fibers. The paper cladding sheet (14) is bonded to the core (12). The paper cladding sheet (14) creates an electroconductive surface (14a) of the building construction product (10). The paper facing sheet (14) can be bonded to the core (12) by any means. The core (12) can comprise a cementitious material and / or an adhesive, and the paper facing sheet (14) can be bonded to the core (12) during the setting reaction of the cementitious material. Alternatively or additionally, the paper facing sheet (14) can be bonded to the core (12) with an adhesive, for example, starch, glue, or polymeric binders. The paper facing sheet (14) can comprise an adhesive layer, and / or an adhesive can be applied to the paper facing sheet (14) and / or the core (12) to bond the paper facing sheet (14) to the core (12).Alternatively, the paper facing sheet (14) can be attached to the core (12) with nails, adhesive tape, staples, screws, or any other means generally used in construction to attach a paper facing sheet to a surface. In some embodiments, the paper facing sheet (14) can be wrapped around the core (12). The building product (10) can be a wall panel, fiberboard, tile, ceiling tile, floor tile, door, plank, frame, roofing tile, or any other building product. In Figure 1, the building product (10) can be characterized by its length (denoted as L in Figure 1) and core thickness (12) (denoted as W in Figure 1). Since the length L is greater than the thickness W, the building product (10) has two long surfaces, one of which is the electrically conductive surface (14a) shown in Figure 1. As can be seen in Figure 1, the building construction product has a second long surface (not shown in Figure 1) on the opposite side of the core (12) of the electrically conductive surface (14a). This second long surface can be covered with a paper cladding sheet (16). The second paper cladding sheet (16) can be a paper cladding sheet that does not comprise carbon fibers, or the second paper cladding sheet (16) can also comprise carbon fibers and create a second electrically conductive surface. In alternative configurations, the cladding sheet QP17. The paper lining (16) may be absent or replaced with a fiberglass mat (not shown in Figure 1). In Figure 1, the paper lining sheet (16) and the paper lining sheet (14) are applied directly onto the core (12). In other embodiments, there may be one or more intermediate layers (not shown in Figure 1) placed between the core (12) and the paper lining sheet (16) and / or the paper lining sheet (14). The one or more intermediate layers may be one or more of the following: an adhesive layer, a fiberglass mat, an insulating material, another paper facing sheet, a reinforcing layer such as a mesh or sill, a coating, a primer, or any combination thereof. In some embodiments (not shown in Figure 1), the product (10) does not comprise the core (12) and / or the paper facing sheet (16). In these embodiments, the building construction product comprises the paper facing sheet (14) with the electroconductive surface (14a). In some embodiments, the electroconductive surface (14a) is applied to the front surface of the building product that is facing into an enclosure, for example, a room, after the building product (10) has been installed. In other embodiments, the electrically conductive surface (14a) encloses an installation on the exterior. In these embodiments, the other paper cladding sheet (16) is oriented towards the interior of the enclosure, for example, a room, while the electrically conductive surface is on the opposite side. The core (12) may be a cementitious core comprising one or more layers of cement, gypsum, and / or any other hydraulic material. The core (12) may further comprise organic and / or inorganic fibers, a binder, organic and / or inorganic fillers, and other compounds. In some embodiments, the core (12) is a gypsum core as conventionally used in wall panels, fiberboard, or ceiling tiles. In other embodiments, the core (12) may be a plank, mat, subfloor, pipe, or any other building substrate with one or more surfaces. The paper cladding sheet (14) comprising carbon fibers is herein referred to as an electroconductive paper cladding sheet. The electroconductive paper cladding sheet herein is capable of conducting electric current and has a low electrical resistance and resistivity compared to a conventional paper cladding sheet, such as Manila paper cladding or any other conventional paper cladding sheet used in wall panels. These conventional paper cladding sheets do not comprise carbon fibers and have infinite resistance. This distinguishes the electroconductive paper cladding sheet described herein from a conventional paper cladding sheet that does not comprise carbon fibers. The conventional paper cladding sheet is not a conductive material and has infinite resistance. The electroconductive paper cladding sheet described herein has electrical conductivity and good electromagnetic shielding capabilities. In another aspect, the conductive paper cladding sheet is a building construction product that can be used to create an electrically conductive surface on any surface or part thereof, including a wall, partition, roof, ceiling, floor, window, or door. In these embodiments, the conductive paper cladding sheet can be used to reinforce an installation, such as a research facility or conference room, including wall panels that have already been installed. For example, the conductive paper cladding sheet described herein can be used as wallpaper for installation in a room or any other installation or enclosure. The electroconductive paper cladding sheet of QP17. Ln / Lznz / E / YILI The present description may be single-layer paper comprising carbon fibers or multi-layer paper comprising carbon fibers. The multi-layer electrically conductive paper may comprise several core filler layers, typically 2 to 5 layers, pressed together with a surface layer. With reference to Figure 2, it represents a cross-sectional view of one of the electroconductive multilayer papers comprising carbon fibers according to the present description, generally (70). The electroconductive multilayer paper (70) comprises a surface layer (72) pressed together with several filler layers: (74), (76), (78), and (78) stacked beneath the surface layer (72) in a stack. Whereas only four filler layers are shown in Figure 2, other papers according to the present description may comprise more than four, for example, five, six, or seven filler layers, or fewer than four, for example, one, two, or three filler layers. Whereas only one surface layer (72) is shown in Figure 2, in other embodiments according to the present description, the electroconductive paper cladding sheet may comprise a second surface layer positioned as an outer layer on the side opposite the surface layer (72).Even in other embodiments, the surface opposite the surface layer (72) that lies beneath the layer (80) can be coated with an adhesive coating (not shown in Figure 2). This adhesive coating, when present, facilitates the adhesion of the electroconductive paper to the core (12) of the building construction product (10). In the electroconductive paper (10) of the present description, the carbon fibers are incorporated at least in the surface layer (72) which will be on the surface (electroactive surface (14a) in Figure 1) in the building construction product (10) of the present description. In some of the electrically conductive multilayer paper cladding sheets, carbon fibers can be incorporated in all layers; for example, all layers (72, 74, 76, 78, and 80) comprise some carbon fibers, even if the quantity of carbon fibers may differ between different layers. In other electrically conductive multilayer paper cladding sheets, carbon fibers can be incorporated only in the surface layer (72). In still other electrically conductive multilayer paper cladding sheets, carbon fibers can be incorporated in the surface layer (72) and in the filler layer (74) placed immediately beneath the surface layer (72). In yet another electrically conductive multilayer paper cladding sheets, carbon fibers can be incorporated in the surface layer (72), in the filler layer (74), and in the filler layer (76) placed immediately beneath the filler layer (74).Other forms include electroconductive paper, in which carbon fibers are incorporated into the surface layer (72) and carbon fibers are also incorporated into 1 to 4 of the filler layers stacked below the surface layer (72). In the building construction product (10), the layer (80) is in contact with the core (12) of the building construction product (10). In some embodiments, this layer comprises carbon fibers in addition to or instead of the surface layer (72). Various electrically conductive carbon fibers are suitable for producing the electrically conductive paper cladding sheet described herein. Suitable carbon fibers include those produced by any conventional method from polyacrylonitrile, iron, and / or a pitch comprising aromatic hydrocarbons. The pitch may be of vegetable or petroleum origin. The length and diameter of carbon fibers can vary. Suitable carbon fibers include fibers composed primarily of carbon atoms with a diameter in the range of 1 to 15 micrometers (μm) and a length in the range of 1 to 20 millimeters (mm). Carbon fibers of other lengths and / or diameters may also be suitable. Carbon fibers can be coated with a coating comprising one or more chemical compounds. The coating may be organic and may comprise polyvinyl alcohol or any other organic or inorganic compound. The length and / or diameter of carbon fibers in any particular electroconductive paper cladding sheet of this description may be adjusted as required to achieve a particular electromagnetic shielding capability and electrical conductivity as needed. For the purposes of this description, carbon fibers with a length of less than 10 mm, for example, 2 mm, 3 mm, 4 mm, or 5 mm, are referred to as short carbon fibers. Short carbon fibers have a diameter in the range of 1 to 15 μm. Short carbon fibers have a length of 1 mm to 10 mm. Preferably, short carbon fibers have a length of 1 mm to 5 mm. For the purposes of this description, carbon fibers with a length of 10 mm and more, for example, 10 mm, 11 mm, 12 mm, 13 mm, or 14 mm, are considered long carbon fibers. Long carbon fibers have a diameter in the range of 1 to 15 μm. Long carbon fibers have a length of 10 mm to 20 mm. Preferably, long carbon fibers have a length of 10 mm to 15 mm. In some embodiments, the electroconductive paper cladding sheet described herein comprises short carbon fibers. In other embodiments, the electroconductive paper cladding sheet described herein comprises long carbon fibers. At least some of the electrically conductive paper cladding sheets ^17 LO / įZРZ / E / YILI described herein may comprise a combination of carbon fibers of different lengths. In some embodiments, the electrically conductive paper cladding sheet comprises a mixture of long and short carbon fibers, which may be blended together in at least the surface paper layer. In other embodiments, the electrically conductive paper cladding sheet described herein may comprise the surface layer and one or more filler layers beneath the surface layer containing short carbon fibers, and / or one or more filler layers beneath the surface layer containing long carbon fibers, and / or one or more filler layers beneath the surface layer containing a combination of short and long carbon fibers. At least some carbon fibers can be coated or surface-treated to improve miscibility in a water-based paper pulp and further improve the intermingling of the carbon fibers with cellulose fibers. At least in some of the embodiments, the electroconductive paper cladding sheet may comprise carbon nanotubes that can be used in combination with carbon fibers in the surface layer and / or one or more filler layers as required. In addition to carbon fibers, the conductive paper cladding sheet (^17 Lnz LznzzezviAi) comprises cellulose fibers. Any cellulose fiber typically used in wall panel paper cladding sheets may also be suitable for the conductive paper cladding sheet described herein. The cellulose fibers may be virgin fibers produced from a natural source, such as wood or cotton, for example, by chemical and / or mechanical methods. The cellulose fibers may be recycled cellulose fibers obtained by re-shredding recycled paper. The cellulose fibers may be any combination of virgin and recycled cellulose fibers. Preferred sources of recycled cellulose fibers include old corrugated paper, kraft paper scraps, and used newspapers. In electrically conductive paper cladding, cellulose fibers are the primary fiber source in any layer of the conductive paper. It should be noted that the total amount of carbon fibers per layer can vary and is adjusted as needed to produce the electrically conductive paper cladding with a specified electrical conductivity and electromagnetic shielding capability required for any particular application. The total amount of carbon fibers can also be adjusted by mixing short and long carbon fibers and / or by using only long or only short carbon fibers as required. Typically, using long carbon fibers allows for higher electrical conductivity with smaller quantities of carbon fibers compared to using short carbon fibers. Preferably, the conductive paper cladding sheets may comprise carbon fibers in an amount from 2% by weight (abbreviated as wt in the remainder of this description) to 30% by weight of the total fibers in a layer, the remainder of the fibers being cellulose fibers, for example, recycled and / or virgin cellulose fibers. In some embodiments, the conductive paper cladding sheets may comprise carbon fibers in an amount from 2% by weight to 30% by weight of the total fibers in a layer, the remainder of the fibers being cellulose fibers, for example, recycled and / or virgin cellulose fibers. In some embodiments, the conductive paper cladding sheets may comprise carbon fibers in an amount from 2% by weight to 20% by weight of the total fibers in a layer, the remainder of the fibers being cellulose fibers, for example, recycled and / or virgin cellulose fibers.In some embodiments, the electroconductive paper cladding sheets may comprise carbon fibers in an amount of 2% to 10% by weight of the total fibers in a layer, where the remainder of the fibers are fibers of. QP17. Ln / įZРZ / B / YILI cellulose, for example, recycled and / or virgin cellulose fibers. In some embodiments, the electroconductive paper cladding sheets may comprise carbon fibers in an amount of 2% to 10% by weight of the total fibers in a layer, where the remainder of the fibers are cellulose fibers, for example, recycled and / or virgin cellulose fibers. In some embodiments, the electroconductive paper cladding sheets may comprise carbon fibers in an amount of 2% to 5% by weight of the total fibers in a layer, where the remainder of the fibers are cellulose fibers, for example, recycled and / or virgin cellulose fibers. In some embodiments, the electroconductive paper cladding sheets may comprise carbon fibers in an amount of 5% to 10% by weight of the total fibers in a layer, where the remainder of the fibers are cellulose fibers, e.g., recycled and / or virgin cellulose fibers. If the multilayer electrically conductive paper comprises carbon fibers in one or more filler layers in addition to the surface layer, the amount of carbon fibers in each of the filler layers may be the same or different. Furthermore, the amount of carbon fibers may be the same or different from the amount in the surface layer. In some embodiments, the surface layer may comprise from 5% to 10% by weight of carbon fibers of the total fibers in the surface layer, while one or more filler layers may comprise from 2% to 5% by weight of carbon fibers of the total fibers in the filler layer. In the electroconductive paper described herein, carbon fibers can be incorporated in several different ways. In some embodiments, the carbon fibers are interwoven with cellulose fibers uniformly throughout a layer. In these embodiments, the carbon fibers are randomly oriented within the layer. In other configurations, carbon fibers can be incorporated throughout a layer in a pattern, creating an electroconductive matrix within the layer. Some distribution patterns are such that the carbon fibers are oriented in a particular direction; for example, the carbon fibers are oriented parallel or nearly parallel to each other. If, in addition to the surface layer, one or more filler layers comprise carbon fibers, the carbon fiber orientation pattern between two adjacent layers of a multilayer paper may be the same or different. The electroconductive paper described herein can be manufactured by incorporating carbon fibers into various types of paper, including those described in U.S. Patent Publication 2012 / 0088114. Suitable paper types include Manila with a smooth calendered finish and Newsline with a rougher finish. Both paper types are multi-ply, with at least one layer of QP17. Ln / įZРZ / B / YILI coating (surface) and several filler layers. Manila's coating layers typically use recycled hardwood pulp paper with shorter fibers compared to the filler layers, which use longer fibers. Newsline paper typically has the same type of fiber in its coating layer as is used in its filler layers. The surface layer comprising carbon fibers may also comprise old corrugated containers (OCC) or double-coated Kraft waste paper (DLK).With reference to Figure 3, this description further provides methods for manufacturing the electroconductive paper cladding sheet described herein. These methods may utilize a conventional papermaking press with modifications. For example, a Fourdrinier machine or any modification thereof may be used. The press may be further modified as required to allow the incorporation of carbon fibers in a pattern where the orientation of the carbon fibers is predetermined. The setup may include one or more computer processors with software that calculates the quantity and / or pattern of carbon fibers as required to achieve a particular level of electromagnetic shielding with the electroconductive surface to be produced.Therefore, the present methods produce electroconductive paper cladding sheets with a predetermined electromagnetic shielding capacity and as required for any particular application. Figure 3 is a block diagram, typically 100, illustrating a method for manufacturing the electrically conductive paper cladding sheet (14). In this method, a paper pulp is mixed. The paper pulp is a very dilute suspension of fibers in water. The paper pulp comprises water, cellulose fibers, carbon fibers, and some other additives. The cellulose fibers can be virgin fibers produced from a natural source, such as wood or cotton, for example, by chemical and / or mechanical methods, recycled cellulose fibers obtained by re-pulverizing recycled paper, or any combination of virgin cellulose fibers and recycled cellulose fibers. Preferred sources of recycled cellulose fibers include old corrugated paper, kraft paper scraps, and used newspapers. Paper pulp may also include one or more of the following additives: a sizing agent, a flocculant, an antifoaming agent, a water-retaining agent, a binder, a filler, a deinking agent, and a pigment. To reduce the surface tension of carbon fibers and improve their miscibility with cellulose fibers in paper pulp, the carbon fibers may be surface-treated, or a surfactant may be added to the paper pulp. Suitable surfactants may include, but are not limited to, ionic and nonionic surfactants with a medium-to-high hydrophobic / lipophilic balance (HLB) of approximately 10 to approximately 18. Suitable dispersants may include naphthalene sulfonate and other alkylbenzene sulfonates, lignosulfonate, fatty alcohol ethoxylates, and alkylphenol ethoxylates. Other surfactants include alkyl sulfates such as ammonium lauryl sulfate and sodium lauryl sulfate, and related alkyl ether sulfates such as sodium laureth sulfate and sodium mirethsulfate, alkyl ether phosphates, alkyl ether phosphates, sodium stearate, and quaternary ammonium salts. Suitable sizing agents may include, but are not limited to, alum, rosin, rosin soup, alkyl ketene dimer, and alkenylsuccinic anhydride. Suitable water retention agents may include, but are not limited to, polyacrylamide and polyethyleneimine. Suitable fillers may include, among others, calcium carbonate, talc, and titanium dioxide. Suitable binders may include, but are not limited to, styrene maleic anhydride copolymer, styrene-acrylate copolymer, and modified starch. If a multi-layer paper sheet is manufactured by pressing together layers that differ in their chemical compositions, such as filler and liner layers, separate paper pulps are prepared for each layer. For example, one pulp is prepared for the liner layers and another for the filler layers. The amount of carbon fibers in paper pulp varies and depends on the requirements for producing a particular electrically conductive surface. Increasing the amount of carbon fibers and / or using longer fibers helps produce an electrically conductive paper coating sheet with stronger conductivity. Typically, a paper pulp for electrically conductive paper can comprise from approximately 2% to approximately 40% by weight of carbon fibers, depending on the total amount of all fibers on a dry weight basis. For example, if a paper pulp is prepared with 95 g of dry cellulose fibers and 5 g of dry carbon fibers, the paper pulp is said to have 5% by weight of carbon fibers, based on the total amount of all fibers on a dry weight basis. The composition of cellulose fibers in any particular paper pulp depends on the type of plies and / or the paper to be produced. Filler plies can be prepared from a hard paper pulp that may include kraft paper scraps and cardboard. Coating plies can be prepared from a paper pulp that includes paper chips and / or newsprint. In the block diagram of Figure 3, paper pulp from an inlet box (block 112) is distributed onto block (114) on a continuously moving forming mesh table, also called a Fourdrinier wire table, where water is drained and a web is formed for a paper layer. The forming paper layer may already contain carbon fibers if the carbon fibers were mixed with cellulose fibers in a paper pulp from which the paper layer is formed. However, some paper layers can be formed from paper pulps that do not contain carbon fibers. After block (114), the forming paper layer, which is formed from a paper pulp that does not include carbon fibers, can be passed to block (116), which is a pattern-forming station. Here, a set of rolls or some other means can be used to embed carbon fibers in a pattern within the forming paper layer. A pattern means that the carbon fibers are oriented in a particular direction; for example, the carbon fibers can be embedded parallel or nearly parallel to each other. The pattern-forming station can be operated by a computer equipped with software that calculates a pattern to be printed. In some embodiments, the pattern-forming stage can be omitted. Next, the forming paper layer, either directly from block (114) or from block (116), is pressed in a pressing station (block 118) by felt rollers. If multi-ply paper is to be manufactured, several layers are stacked together at this stage of the process. The layers are pressed together in block (118). If the layers have different fiber compositions, they can be fed to the pressing station from several different forming mesh tables (not shown in Figure 3). Therefore, a multi-layer paper sheet can be formed comprising several internal filler layers and the surface layer (72) comprising carbon fibers. After block (118), the pressed paper is dried in a multi-roll drying section (block 120) by passing it through a set of felt rollers and additional dryers. From block (120), the dry paper is passed to calenders in block (122), where it is calendered to achieve uniformity. After that, the electrically conductive paper is wound into rolls in block (124) and is ready for various applications. It should be noted that various modifications to the method can be made depending on the application for which the conductive paper will be produced. For example, the conductive paper can be coated with a water-resistant coating and / or carbon fibers can be incorporated in one or more filler layers in addition to the surface layer. In some embodiments, the electroconductive paper can be coated with an adhesive composition on one of the surfaces so that this adhesive layer improves the adhesion of the electroconductive paper to various substrates, such as a concrete wall, a plasterboard, a ceiling tile, metal pipes, wooden planks, or any other building construction surface that needs to be reinforced with an electroconductive surface. Yet another aspect, the present description provides methods for producing a construction product comprising an electroconductive surface. In one embodiment, a wall panel comprising an electroconductive surface is manufactured using conventional gypsum board forming methods and equipment. In these embodiments, a gypsum suspension is prepared with calcined gypsum and water. Typically, a gypsum suspension may comprise various other additives, which may include, but are not limited to, one or more of the following: a binder, a filler, an antifoaming agent, organic and / or inorganic fibers, foam, a dispersant, a set retarder, a set accelerator, a biocide, and / or a colorant. Figure 4 is a schematic diagram of a manufacturing process for a gypsum wall panel with an electroconductive surface, generally (30). A first paper facing sheet (32) is fed from a roll (34) onto a moving conveyor (36). A gypsum slurry (38) is distributed from a mixer (40) onto the first paper facing sheet (32), which in some embodiments is the electroconductive paper facing sheet comprising carbon fibers, as described herein. A second paper coating sheet (42) is deposited onto the gypsum suspension (38) distributed from a roll (44). If the first paper coating sheet (32) does not comprise carbon fibers, this second paper coating sheet (44) is the electrically conductive paper coating sheet comprising carbon fibers, as described herein. It should be noted that in some other embodiments, both paper coating sheets (32) and (44) are the electrically conductive paper coating sheets comprising carbon fibers. Typically, the paper lining sheets (32) and (44) are multi-layer paper lining sheets. When the lining sheet (32) and / or the lining sheet (44) comprise carbon fibers, the carbon fibers are typically incorporated into at least the surface layer of the lining sheets (32 and / or 44) that remains as a void opposite the surface of the lining sheet (32 and / or 44) in contact with the gypsum suspension (38). However, in at least some embodiments, the gypsum suspension can be bonded to the surface layer comprising carbon fibers. Next, a forming wall panel (46) is passed through a forming station with forming means, for example, a roll (48), where the distribution of the gypsum slurry (38) between the first paper facing sheet (32) and the second paper facing sheet (42) is leveled by the forming means, and the forming wall panel (46) of predetermined thickness is formed. As the formed wall panel (46) exits the forming station (48), it moves continuously on the conveyor (36) in a direction indicated by an arrow shown below the conveyor 36. The gypsum slurry (38) sets, and the wall panel with the electroconductive surface (50) is produced. The wall panel (50) is then cut to size and dried in a dryer, for example, an oven. In another embodiment, the present description provides a method for imparting an electroconductive surface to a building product. The building product can be any of the conventional wall panels, fiber boards, tiles, ceiling tiles, windows, floor panels, doors, pipes, planks, frames, or any other building product with at least one surface. The electroconductive paper cladding sheet comprising carbon fibers of the present description can be bonded to a surface of the building product. In some of these applications, the prefabricated self-adhesive electrically conductive paper facing sheet described herein can be used, and / or the electrically conductive paper facing sheet described herein can be coated with an adhesive and then applied to the surface of the building product. This method can be used on surfaces of building products that have already been installed. Other methods described herein include shielding an area, such as a room, a group of rooms, part of a building, or an entire building, from electromagnetic waves. In these methods, the area is enclosed with electroconductive paper cladding sheets. In other forms, construction products with an electroconductive surface comprise a paper screen QP / 7 LO / 17P7 / E / YILI is an electrically conductive, foldable screen. The electrically conductive paper screen comprises the electrically conductive paper facing sheet described herein and one or more suspension means. The suspension means may include one or more boards, for example, plastic, metal, or wooden boards, which can be assembled together to create a frame to which the electrically conductive paper screen is then attached. Wires, self-adhesive strips, ropes, and / or adhesive may be included in addition to or instead of the suspension means. The electrically conductive paper screen may be suspended from a ceiling, a wall, a window frame, a door frame, a wall frame, and / or the electrically conductive paper screen may stand alone supported by a frame. The electrically conductive paper screen can be used to create an enclosure in a part of a room.This enclosure can protect part of a room from electromagnetic waves, for example, when it is necessary to protect some equipment sensitive to electromagnetic waves. The electroconductive paper described here can be used in a variety of applications. One application is creating various enclosures that protect against electromagnetic waves. This can be used to block the transmission of radio waves, including Wi-Fi signals, or to ensure communication only through specific waves authorized within the enclosure. ^17 Lnz LznzzezviAi The building construction products described herein comprise the electroconductive surface created by the electroconductive paper cladding sheet. This electroconductive surface can be used to block electromagnetic waves and / or as an electromagnetic signature (a signal to be detected by one or more detectors) for navigation, including indoor navigation, when an electric field is applied to the surface. The electroconductive surface can also provide tactile sensitivity when an electric field is applied to it. Example 1. Three different types of electroconductive papers were produced. 1) OCC at 70%: 3mm carbon fiber at 30% (base weight -136.71 g / m2[-28 lb / msf]; msf means 1000 square feet) 2) 80% OCC: 3mm 20% carbon fiber (basis weight -136.71 g / m2[-28 Ib / msf]) 3) 90% OCC: 12mm 10% carbon fiber (basis weight -126.94 g / m2[-26 Ib / msf]) All papers were single-ply. Samples were formed in the Williams standard pulp testing apparatus with a 100-mesh sieve. Example 2 The resistance of the electroconductive paper samples QP17. Ln / įZРZ / B / YILI of Example 1 was measured with a Fluke 115 True RMS multimeter. The conductive papers 1, 2, and 3 had the following dimensions: approximately 20 by 10 centimeters (approximately 8 by 4 inches). Results are expressed in kilohms. 1 kilohm = 1000 ohms. Conventional wall panel paper was used for comparison. Graphene-enhanced conductive geotextile Imgne X3 was used as a positive control. 1) OCC at 70%: 3 mm carbon fiber at 30% (base weight -136.71 g / m2[-28 lb / msf]; msf means 1000 square feet) = 0.006 kilohms 2) 80% OCC: 3mm 20% carbon fiber (basis weight -136.71 g / m2[-28 Ib / msf]) = 0.010 kiloohms 3) 90% OCC: 12mm 10% carbon fiber (basis weight -126.94 g / m2[-26 Ib / msf]) = 0.030 kiloohms 4) Graphene-enhanced conductive geotextile Imgne X3; (www.imgne.com) = 1,095 kilohms 5) Conventional SHEETROCK wall panel paper = infinite resistance The electrically conductive paper samples had a resistance ranging from 0.006 kilohms (sample 1) to 0.030 kilohms (sample 3), while conventional wall panel paper without carbon fibers had infinite resistance. This result indicates that the conductivity of the electrically conductive paper cladding sheet can be regulated as required by varying the length and / or quantity of carbon fibers in the paper cladding sheet. It is hereby stated that, as of this date, the best method known to the applicant for putting the aforementioned invention into practice is the one that is clear from the present description of the invention. QP17. Ln / ίΖΠΖ / Β / ΥΙΛΙ
Claims
Having described the invention as above, the following claims are claimed as property:
1. A building construction product with an electroconductive surface, characterized in that it comprises a core with one or more surfaces covered by an electroconductive paper comprising carbon fibers, wherein the electroconductive paper is bonded to the one or more surfaces of the core.
2. The building construction product according to claim 1, characterized in that the electroconductive paper comprises a surface layer and one or more filler layers stacked in a pile beneath the surface layer, and wherein the electroconductive paper comprises carbon fibers in at least one of the following layers: the surface layer, one or more filler layers, or any combination thereof.
3. The building construction product according to claim 1 or 2, characterized in that it is a wall panel, a fiberboard, a ceilingboard, a floor tile, a door, a plank, a frame, an electroconductive paper screen or a roof tile.
4. The building construction product according to claim 1 or 2, characterized in that it is a wall panel with two long surfaces, and wherein the electroconductive paper is attached to at least one of the long surfaces of the wall panel.
5. The building construction product according to claim 1 or 2, characterized in that the carbon fibers of the electroconductive paper have a diameter in the range of 1 to 15 micrometers (μM) and a length in the range of 1 to 20 millimeters (mm).
6. The building construction product according to claim 1 or 2, characterized in that the electroconductive paper is further characterized by one or more of the following features: a) the carbon fibers are short carbon fibers, long carbon fibers or any combination thereof; b) the carbon fibers are intermingled with cellulose fibers in random orientation; and / or c) the electroconductive paper further comprises carbon nanotubes.
7. The building construction product according to claim 2, characterized in that the carbon fibers are in an amount of 2% by weight to 40% by weight of total fibers per surface layer of the electroconductive paper, and wherein the remainder of the fibers in the surface layer of the electroconductive paper are cellulose fibers.
8. The building construction product of QP17. Ln / įZРZ� / В / YΙЛΙ in accordance with claim 1 or 2, characterized in that the carbon fibers are embedded in a pattern.
9. The building construction product according to claim 1 or 2, characterized in that 5 the carbon fibers are oriented parallel or almost parallel to each other.
10. A method for imparting an electroconductive surface to a building construction product, characterized in that it comprises: 10 a) forming a paper sheet from a paper pulp comprising carbon fibers and / or embedding carbon fibers in the forming paper sheet in a pattern; b) drying the paper sheet; and c) bonding the paper sheet to the building construction product. 15 QP17. Ln / ίZЖРZ / B / YΙΛΙ