IL270660B2 - Readymade flexible continuous cement sheet for coating construction slabs - Google Patents

Description

39506/19 READYMADE FLEXIBLE CONTINUOUS CEMENT SHEET FOR COATING CONSTRUCTION SLABS Field of the Invention The present invention relates to a thin flexible sheet of cementitious material for coating construction panels. Particularly, the invention relates to a cost-effective method of manufacturing continuous cementitious layers for coating foamed construction panels, the layers being used immediately or being conveniently stored and transported for use anytime or anywhere else.

Background of the Invention Composite panels comprising expanded or extruded polystyrene (PS) cores and cementitious coatings have become an integral part of modern building construction. Since more than 90% volume of the PS may be air, PS slabs can act as a highly efficient thermal insulator. The coated panels make superior insulation against thermal and vibration impacts. The lightweight panels also make the whole structure seismically safer. The coated panels are resistant to moisture and to microbial attacks, and are used for both interior and exterior purposes, being employed in walls, floors, ceilings, roofs, and foundations. The coating strengthens the core and may serve as a base for additional surface changes, including ceramic tiles, plaster, and others. Other polymers are used in construction, including polyurethane (PU).

However, conventional processes for producing cementitious panels are quite complex, demanding too much working space and too complex manufacturing equipment, the resulting products being costly and not sufficiently competitive with less environmental friendly construction elements. The number of problems include, for example, premature or delayed setting of the slurry on the coated slab, difficulties in feeding the slurry upon a moving substrate, difficulties about the maintenance of cement delivering equipment and about clogging, and uneven deposition of the slurry on the slabs. It is 39506/19 therefore an object of the invention to provide a simpler process for obtaining coated polystyrene or other slabs.

It is another object of this invention to provide a cost-effective process requiring less production space and equipment than known processes for manufacturing coated slabs or sandwich slabs, including panels comprising PS, PU, fiberglass, mineral or glass fibers, the panel being coated with cement-like thin layers.

Other objects and advantages of present invention will appear as the description proceeds.

Summary of the Invention This invention provides a continuous flexible cement sheet roll for coating construction slabs, the sheet comprising a flexible cement layer, which has a thickness of between 0.3 to 6 mm, such as between 0.5 and 5 mm, and which comprises a) essentially inorganic mortar and b) up to 15% polymeric binder. When the amount of a component in a mixture is expressed in % units, the weight % of the component relative to the weight of the whole mixture is intended. The flexible cement sheet roll of the invention comprises, in one embodiment, a reinforcing layer of a thickness lower than the thickness of said cement layer, selected from films of a nonwoven fabrics, layers of organic or inorganic fibers, polymer webs, chop strand mat, and fiberglass mats, among others. In one embodiment, the flexible cement sheet roll of the invention comprises a polymeric foil which lines said cement layer; the foil is attached on one of the sheet surfaces. In some embodiments, the flexible cement sheet comprises said reinforcing layer, usually embedded within the cement layer, in other embodiments the cement sheet comprises said attached foil, and in other embodiments the cement sheet comprises both. Said flexible cement sheet of the invention preferably comprises hydraulic cement; sand; water; polymeric binder; and up to 10% additives selected from thickeners, fillers, plasticizers, surfactants, dispersants, antifoams, rheology affecting agents, hydrophobicity adjusting agents, and flame retardants (FRs). Said cement layer in the flexible cement sheet roll of the invention usually comprises i) 40- 39506/19 -3­ 70% hydraulic cement; ii) 10-25% sand; iii) up to 10% chalk or calcium carbonate; iv) 5­15% water; v) 5-15% polymeric binder; and vi) up to 5% additives selected from thickeners, fillers, plasticizers, surfactants, dispersants, antifoams, rheology affecting agents, hydrophobicity adjusting agents, and flame retardants (FRs). In a preferred embodiment of the the flexible cement sheet roll, said cement layer comprises i) 50­60% hydraulic cement of Portland types; ii) 13-23% quartz sand; iii) 5-9% chalk or calcium carbonate; iv) 8-12% water; v) 5-9% polymeric binder comprising agents selected from acrylates, styrene acrylic copolymers, styrene and butadiene copolymers, epoxy resins, methyl methacrylate, unsaturated polyester resins, polyurethane, and vinyl esters; and vi) 0.5-5% additives selected from thickeners, fillers, plasticizers, surfactants, dispersants, wetting agents, antifoams, rheology affecting agents, hydrophobicity adjusting agents, flame retardants (FRs), preservatives, and dyes. In some embodiments of the invention, the flexible cement sheet roll comprises a reinforcing layer comprising fiberglass embedded in said cement layer. In other embodiments of the invention, the flexible cement sheet roll comprises a polymeric foil which lines said cement layer, the foil comprising a polymer fabric or textile, preferably nonwoven fabric, such as for example comprising polyester or polyester terephthalate.

The invention relates to a flexible cement sheet roll as above described, for coating construction elements including foamed or extruded polymeric slabs, polystyrene or polyurethane panels, carton slabs, or slabs comprising mineral or organic fibers, but also for coating the surfaces of other construction elements including beams and columns, comprising various construction materials including steel, said sheet comprising a cement layer of a uniform thickness of between 1 and 4 mm, optionally a reinforcing layer embedded in said cement layer, and optionally a polymeric foil lining said cement layer, wherein said roll may have a width of 0.2-2 m, and said sheet may have a length of 50-300 m.

The invention provides a process for manufacturing a continuous flexible cement sheet for coating construction elements, comprising i) preparing a cement mortar mixture by homogenizing hydraulic cement, sand, water, 5-15% polymeric binder added to the 39506/19 mixture as a fine dispersion, and up to 10% additives comprising agents selected from plasticizers, superplasticizers, antifoams, thickeners, fillers, dispersants, and viscosity adjusting agents; ii) layering said cement mortar mixture onto a heat-resistant surface of a conveyor, the surface optionally covered by a polymeric foil, thereby forming a wet cement mortar layer of a thickness of from 0.5 to 5 mm; iii) optionally embedding in said wet cement mortar layer a reinforcing layer of a thickness lower than the thickness of said wet cement mortar layer, selected from a film of a nonwoven fabric, a layer of organic or inorganic fibers, a polymer web, chop strand mat, and fiberglass mat; iv) moving said heat resistant surface, optionally with said polymeric foil, bearing said wet cement mortar mixture, optionally with said reinforcing layer, through an oven set at 110-140°C in which said wet cement mixture sets, thereby forming a flexible solid layer; v) peeling said flexible solid layer from said heat resistant surface, optionally with said polymeric foil being attached to said flexible solid layer and lining said flexible solid layer, thereby obtaining said continuous flexible cement sheet; vi) rolling said flexible cement sheet up, thereby obtaining a roll of readymade continuous separate cement sheet for immediate or future use in coating construction elements; the continuous sheet being enough strong and flexible to be unfolded and glued on the surface of said construction elements, including foamed or extruded slabs, polystyrene or polyurethane panels, carton slabs, slabs comprising mineral or organic fibers, and metal columns or beams. The process of the invention preferably comprises i) preparing said homogeneous cement mortar mixture by mixing 35-60% hydraulic cement, 8-20% quartz sand, up to 8% of chalk or calcium carbonate, 15-30% water, 5-15% polymeric binder added to the mixture as a concentrated fine dispersion, and up to 4% additives comprising agents selected from plasticizers, superplasticizers, antifoams, thickeners, fillers, dispersants, surfactants, dispersants, rheology affecting agents, hydrophobicity adjusting agents, FRs, dioctylphthalate, aluminum hydroxide, magnesium hydroxide, cellulose, nylon, fume silica, perlite, vermiculite, glass, PP, basalt, and other suitable components compatible with the described mixture; ii) layering said cement mortar mixture onto said heat-resistant surface, the surface comprising a Teflon surface of a belt conveyor 0.2-2 m wide, optionally covered with said polymeric foil; iii) optionally embedding said reinforcing layer in said wet cement mortar layer, the reinforcing layer 39506/19 comprising fiberglass; iv) moving said heat resistant surface bearing said wet cement mixture optionally with said reinforcing layer into an oven set at 120-130°C, in which said wet cement mortar mixture sets to form said flexible solid layer; v) peeling said layer from said foil, optionally together with said polymeric foil which becomes an integral part of the produced flexible sheet, thereby obtaining said continuous flexible cement sheet, optionally lined with the foil; vi) rolling said flexible sheet up, thereby obtaining a roll of continuous cement sheet having a length of 20-200 m for immediate use or for storing for a future use; the continuous sheet being enough strong and flexible to be unfolded and glued onto the surface of said construction elements, including foamed and extruded slabs, polystyrene or polyurethane panels, carton slabs, slabs comprising mineral or organic fibers, and metal columns or beams.

The process for manufacturing a continuous flexible cement sheet for coating construction elements according to the invention, the sheet most preferably being folded and rolled up in compact rolls, easy for manipulation and transport, is performed in a continuous manner or in a batch manner. Said polymeric foil which lines the flexible cement layer is preferably selected form nonwoven fabric webs.

In one aspect, the invention relates to a process for manufacturing a building composite panel comprising a polymer slab core and a cement coat attached at least on one side of the slab, comprising i) preparing a cement mortar mixture by homogenizing hydraulic cement, sand, water, 5-15% polymeric binder added to the mixture as a fine dispersion, and up to 10% additives comprising agents selected from plasticizers, superplasticizers, antifoams, thickeners, fillers, dispersants, and viscosity adjusting agents; ii) casting said cement mortar mixture onto a heat-resistant surface of a conveyor, the surface optionally covered by a polymeric foil, thereby forming a wet cement mortar layer of a thickness of from 0.5 to 5 mm; iii) optionally embedding in said wet cement mortar layer a reinforcing layer of a thickness lower than the thickness of said wet cement mortar layer, the reinforcing layer being selected from a film of a nonwoven fabric, a layer of organic or inorganic fibers, a polymer web, an alkali resistant mat, chop strand mat, and fiberglass mat; iv) setting cement mortar layer by 39506/19 exposing it to a temperature of 110-140°C, in a continuous or in a batch manner, thereby providing a solid and flexible cement layer; v) peeling said flexible cement layer, optionally with said polymeric foil attached to said flexible cement layer, thereby obtaining a continuous flexible cement sheet; vi) folding the sheet to provide a roll of a separate readymade flexible cement sheet; vii) applying glue on one side of said slab core or on one side of said flexible cement sheet after unfolding the flexible cement sheet from the coil, and pressing said cement sheet onto said core, thereby obtaining a composite panel coated on one side; viii) optionally gluing said flexible cement sheet on the second side of said slab, thereby obtaining a sandwich building composite panel; and ix) clearing and cutting the coated slab to desired size; thereby obtaining building structure elements coated on one or two sides, including sandwich-structured polystyrene panels coated on both sides.

Said additives in the preparation of the mortar cement mixture may be added up to 10%, usually up to 5%, for example up to 4%, such as up to 3%. Usually, one additive is added to up to 1%, such as up to 0.4%, or up to 0.3% or up to 0.2%, or between 0.1% and 1.0%.

Said polymeric binder is preferably added to the wet mortar cement mixture in the form of a latex, namely a fine dispersion in a suitable solvent, often water. In describing the working mixtures, such as wet mortar cement mixture, total water amount is given, including free added water and water comprised in the added dispersions. The binder dispersion, even when related to as a polymeric binder, may comprise polymers, oligomers, or monomers in some stages of the process, in various combinations, and the final polymeric state may be achieved only after admixing the binder dispersion or latex, and after heating the mortar cement mixture in said oven. The polymer, oligomer, and monomer components may comprise known chemistries and chemical species, including acrylates, styrenes, urethanes, epoxies, styrene-butadiene, and combinations thereof. The dispersions usually contain 40-60% solids. 39506/19 An important aspect of the invention is manufacturing of coated construction elements, including columns, beams, walls, and importantly building panels coated with cement layer, for which the invention provides easy-to manipulate, readymade rolls of separate cement layer, which is flexible and can be easily unfolded to be glued onto any construction surface, particularly on the surfaces of foamed and extruded polymer slabs.

The rolls may have any suitable dimensions; the width of the unfolded sheet being for example 0.25 m or more, such as 0.5 m, 0.75 m, 1 m, 1.25 m, 1.5 m, 1.75 m, or 2 m or more. The length of the continuous flexible sheet on the roll may be for example 50 m or more, such as 100 m, or 150 m, or 200 m, or 250 m, or 300 m, or more than 300 m. The folded roll, essentially having cylindrical shape, may have said cylinder's diameter of about 0.25 m, or about 0.5 m or about 0.75 m, or about 1 m, or more than 1 m. A flexible sheet of a thickness of 5 mm will roll up to a cylinder of more than 1 m in diameter if the sheet should have a length of above 150 m, whereas a thinner flexible sheet of 1 mm thickness will roll up to a cylinder of below 0.5 m in diameter if the sheet should have a length of more than 150 m.

The flexible sheet roll of the invention can be immediately used, or stored after packaging and used later, cost effectively and in a technically simple manner. The stable and flexible readymade, separate cement layer sheet is enough robust and stable to be easily unfolded and glued onto a surface of any construction element which requires creating a cement surface, while obviating obstacles and drawbacks of available procedures, and while precluding complex activities usually associated with unwieldy mortar/cement preparation and application steps.

Detailed Description of the Invention It has now been found that the cement-coated polystyrene (PS) slabs can be manufactured in a simple and environmental friendly process, doing with less working space and less complex manufacturing equipment than the known processes, while providing cost-effective products of any desired dimensions. The process of the 39506/19 invention precludes the problems with moving the panel to be coated to the sites of the coating activities, problems with premature or delayed setting of the formed cement slurry, problems with uneven deposition of the slurry on the slabs, and difficulties about the maintenance of cement delivering equipment and about clogging.

The invention preferably provides PS panels coated with a cement layer, either made of expanded polystyrene (EPS) or extruded polystyrene (XPS), either coated on one side or on two sides. The continual flexible cement sheet may be advantageously employed for coating other polymer slabs and even other building elements. The method of the invention avoids cumbersome steps of existing methods, such as transporting PS or other slabs through coating machines whereby forming a cement layer on one side of the slab, embedding fiberglass within said layer on the slab, sawing the slab with a layer in desired pieces, and repeating the coating on the other side of the slab. The method of the invention provides a cement layer entirely separate from the slab and combines the separate cement layer with the slab when the layer is not wet any more. Moreover, the separate cement layer is flexible and well workable, so that it can be rolled up to provide rolls of a separate readymade cement layer to be glued onto PS slabs anytime and anywhere needed.

The separate cement layer sheet according to the invention is prepared from a mixture comprising 15-70% cement, 5-30% polymerizable or polymerized latex dispersion, 5­25% sand, up to 10% chalk or lime or calcium carbonate, 10-35% water, and additives comprising agents selected from thickeners, fillers, plasticizers, surfactants, dispersants, antifoams, rheology affecting agents, wetting agents, hydrophobicity adjusting agents, flame retardants (FRs), and others. Percent values relate to weight percent throughout. In some embodiments, the latex emulsion comprises styrene-butadiene (SB). In some embodiments, the additives comprise plasticizers like dioctylphthalate. In some embodiments, the FR comprise aluminum hydroxide or magnesium hydroxide. In some embodiments, the fillers comprise polymers like cellulose or nylon. In some embodiments, the fillers comprise fume silica or perlite. 39506/19 The wet mixture for producing the cement layer may comprise, in some embodiments, 30-70% cement, 5-20% latex dispersion, 5-25% quartz sand, 2-10% chalk or calcium carbonate, 5-30% water, 0.5-10% total additives; the amount of dry polymer binder in the mixture may be 2-15%, such as 3-10%; the total amount of water in the mixture may be 7-45%, such as 8-35%. In some embodiment, said mortar-like wet mixture for producing the flexible cement layer may comprise, 40-60% cement, 10-20% latex emulsion, 10-25% quartz sand, up to 10 chalk or calcium carbonate, 10-20% water, 0.5­1% superplasticizer, and antifoam, thickener, filler, dispersant, surfactant, viscosity adjusting agent, each one in an amount between 0.1 to 1.0%; the amount of dry polymer binder in the mixture may be 4-12%, such as 5-10%; the total amount of water in the mixture may be 15-35%, such as 20-30%. The wet mixture for producing the cement layer may for example comprise 40-60% cement, 10-16% latex dispersion, 10­22% quartz sand, 4-9% chalk, 5-25% water, and 0.8-4% total additives, while the amount of dry polymer binder may be 5-8%, and the total amount of water in the mixture may be 15-32.

Said viscosity adjusting agents may comprise rheological agents such as cellulose to bind water. Said latex dispersion may comprise polymer or polymerizable components. A part of the cement or sand in the wet mortar mixture may be replaced with calcium oxide or calcium hydroxide or plaster or calcium sulfate. Water reducing agents may be added, and surfactants to improve workability. If lighter sheet is desired, a component selected from perlite, vermiculite, fume silica, and hollow sand or other light filler may be added. When a flame retardant is desired, aluminum hydroxide or magnesium hydroxide may be added. Hydrophobic agents may be added. For increasing flexibility, dioctylphthalate (DOP) or similar agents may be added. In order to prevent cracks, fibers may be added, such as nylon, glass, PP, basalt, and others. Other additives or fillers compatible with the coating may be employed.

An advantageous aspect of the technology according to the invention is providing a cement layer separately, which facilitates the process and enables to produce thinner panels. Said cement layer, comprising components as described above, is layered, for 39506/19 example by spraying, onto a polymeric surface to bear it to an oven, the surface comprising for example a Teflon coating on a conveyor belt which is a part of the manufacturing equipment, comprising nonwoven textile, such as polyester foil, or PET, placed on the conveyor belt, possibly becoming an integral part of the final, dry, flexible cement layer. In one preferred embodiment, fiberglass is inserted in the wet cement layer, the layer moving to an oven heated to 120-130°C. The wet cement mixture undergoes setting when exposed to said high temperature, providing a solid and firm but flexible cement sheet, which is then peeled from the polymer foil and rolled up on a reel. The peeling step may be combined with the coating step in a continuous process; in a preferred embodiment, the peeled flexible cement sheet is rolled up for storage, marketing, and transport. The desired product is preferably a reel or roll of a flexible cement layer for use in coating foamed polymer core, either on one side or on both side of the core slab. In some embodiments, the sheet is wound on a reel core; in other embodiments, the wound sheet is densely rolled up for storage and transport without any core. Preferably, the slab comprises PS slabs, and the process of the invention provides composite building panels comprising either PS coated with said flexible cement sheet on one side, or sandwich panels comprising PS slab coated on both sides.

One of the advantageous features of the invention is providing a separate flexible cement sheet, readymade for future use in coating foamed slabs to provide building panels. In a preferred embodiment, the flexible cement sheet prepared for coating slabs, such as foamed polymer slabs like PS or PU slabs, is rolled up on rolls stable and ready for any future use, the flexible cement sheet usually having a thickness of 0.3-mm, preferably 0.5-5 mm, such as 1-4 mm, for example 2-3 mm, and being rolled as sheets for example 20-200 cm wide, and 50-300 m long, the rolls having the form of cylinders of a diameter usually between 0.2 and 1 m.

The invention provides a process for manufacturing composite panels comprising foamed slabs coated with a cement layer, comprising a step of gluing the readymade cement sheet of the invention as above described onto foamed polymer slabs. The 39506/19 slabs are combined with the cement sheet on one or both sides while employing glue between the foamed polymer and the cement sheet. The invention provides composite building panels, preferably in a continuous process comprising steps of spreading glue on the surface of the foamed slab or flexible cement sheet, combining the slab and the sheet, and cutting the composite panels to the desired size and packaging.

A cement layer for coating construction slabs, such as polystyrene panels, readymade and separately pre-prepared for future use, for example as a 1-4 mm thick sheet of flexible cement layer reeled on a roll, for example 1mm x 30 cm x 150 m; the layer may be cast, eventually comprising a fiberglass net, on a teflon conveyor belt, optionally covered with a polyester foil or glass fiber mat or other nonwoven web, to become an integral part of the peeled and rolled up flexible layer, to be placed in an oven at 120- 130°C, and then peeled from the plastic base and rolled.

In one embodiment, the process for manufacturing the flexible sheet of the invention comprises coating said cement composition onto a thin polymer film, such as a textile layer, such as polyester, or onto a conveyor surface which is a part of the manufacturing device preferably comprising a Teflon layer, optionally covered with a nonwoven textile. The polymer surface bears the wet cement layer after its forming to an oven, the layer usually being from 0.5 to 5 mm high; a fiberglass comprising foil or mat or web is preferably sunk into the wet cement layer. The wet layer on said polymer surface which is heat resistant moves to the oven set at 120-130°C, and after solidifying, the essentially dry flexible cement sheet is peeled off the underlying conveyor surface and is rolled up in the end of the production line. In one embodiment, the peeling step is performed in a peeling device. The cement layer may be layered onto a nonwoven textile or a fiber carpet which becomes an integral part of the produced cement sheet. Provided is a flexible cement sheet, optionally with a fiberglass-comprising film inside, the sheet being rolled up. The wet cement may be layered onto a foil which will become an integral part of the sheet, providing a flexible cement sheet with or without fiberglass inside, covered on the bottom with a nonwoven fabric, for example chop strand mat. 39506/19 The process of manufacturing composite building panels according to the invention comprises i) providing rolls of a firm flexible cement sheet, for example 0.5-5 mm thick, for example 50-100 cm wide, and 100-200 m long, ii) gluing either one side of the sheet or one side of a building slab, iii) combining said sheet and said slab with the glue joining them to provide a composite panel for building; iv) cutting the composite panel to desired size; and v) optionally combining the second side of the slab with the sheet by said glue. In one embodiment, said glue is spread onto the surface of the cement flexible sheet and a panel is put onto it. If both panel sides are to be coated, its other side is covered with the glue and the flexible cement sheet is put onto it. The panel such as PS panel may move over the flexible cement sheet unfolded from a roll and covered with glue, the panel is pushed by its bottom side onto the glued surface of the flexible sheet, and one-side coated panel continues to move while being covered with glue on its upper side, while flexible sheet form another unfolding roll is pushed onto the panel upper side, followed by cutting and smoothening the edges of the sandwich panel by cutting means like saws or knives and by smoothening means, after which the sandwich panel is divide into parts of desired sizes, while removing residues and packaging the final composite building panels.

The invention thus provides a special product, process, and system comprising a roll of flexible cement sheet which is formed by a) casting inorganic mortar mixed with polymeric latex onto a heat resistant solid surface optionally covered with a polymeric foil, b) setting the cement, c) peeling the solidified cement, optionally with the foil, from said solid surface, and rolling it up for later use, which comprises d) unfolding and gluing said separate readymade rolled sheet onto construction slabs such as PS panels.

This invention relates to a process for producing composite building panels comprising cement-coated slabs, wherein a slurry of mortar and polymeric latex is cast on a solid surface, optionally covered with a polymer foil, and then it is set at a higher temperature to provide a flexible cement sheet, which is separated from said solid surface, in one embodiment together with the attached foil, and rolled up to be stored as rolls for future use. In a preferred embodiment, the cement sheet is reinforced by 39506/19 embedding into it a fiberglass mat or mesh, which may be unfolded before embedding from a roll. The composite panels exhibit high strength.

The process may employ a feed means for depositing the wet cement mixture upon said polymer foil or web. The mixture has a consistency of slurry or paste, which is uniformly spread onto the surface of a foil or a conveyor in a uniform layer, said foil and conveyor preferably moving like an endless tape having the desired width, such as 50-100 cm. The means may include a metering nozzle having a width slightly less than the width of said tape, and a spreading means providing a thin layer uniformly distributed on the tape, exhibiting a predetermined thickness, such as between 0.5 and mm, for example 1-3 mm. The invention relates to a process providing composite building panels for an indoor or outdoor use, preferably in a continuous manner.

The invention provides a system for manufacturing slabs of foamed or extruded polymer coated on at least one side with a readymade flexible cement sheet, the sheet comprising inorganic materials, including hydraulic cement, sand, chalk, and additives, and a polymeric binder, preferably incorporated in the form of a latex, such as styrene- butadiene latex.

Cements are usually brittle, but the cement mixture of the invention is enough elastic to be rolled to form rolls to be stored, and used either immediately in a process of making composite panels, or preferably for future use. The cementitious material and the polymeric component are homogeneously combined to provide a solid sheet which, however, is enough strong and flexible to be bent and even rolled. The cement is prepared from a mixture comprising inorganic, preferably pozzolanic materials, and organic polymers, with additives ensuring strength and flexibility, including superplasticizer additives. After homogenizing, the shapeable, mortar-like mixture is extruded or poured onto a solid surface, optionally covered with a polymeric foil while adjusting the uniform thickness of the obtained layer, comprising extrusion, troweling, calendaring, rolling, etc. Usually, the process of mortar or cement preparation is quite complex, needs specific material ratios and takes up space and time, and may be 39506/19 cumbersome and messy; therefore, such process may extremely complicate production of mortar/cement coated slabs. The invention separates the process of producing the wet cement mortar and the process of coating the building slabs, while addressing most of the problems known in the field.

The invention will be further described and illustrated by the following examples.

Examples Example 1 A wet cement mixture was prepared by homogenizing the following components (in weight percent): 51% Portland cement, 13% water, 13% quartz sand, 6.5% chalk, 13% binder latex purchased from EOC Belgium (styrene-butadiene emulsion L 6066, 48% solids), 0.25% antifoam, 0.25% thickener, 0.25% dispersant, 0.8% dioctylphthalate as superplasticizer, 0.9% perlite, and 0.4% wetting agent. The mixture was spread on a nonwoven polyester foil (PE) band to form a layer 2 mm thick, a fiberglass based web of the width about 1 mm was pushed into the wet mixture layer, the foil with the cement layer and fiberglass was placed in an oven at 125°C for 8 minutes. A flexible cement layer was obtained, being enough strong to be peeled from the PE foil and enough flexible to be rolled without forming cracks.

Example 2 A wet cement mixture was prepared by homogenizing the following components (in weight percent): 46% Portland cement, 19% water, 17% quartz sand, 5% chalk, 12% binder latex (styrene-acrylic copolymer emulsion), 0.2% antifoam, 0.2% thickener (cellulose), 0.2 superplasticizer, and 0.2% wetting agent. The mixture was spread on a nonwoven polyester foil (PE) band to form a layer 3 mm thick, a fiberglass based web of the width about 1 mm was pushed into the wet mixture layer, the foil with the cement layer and fiberglass was placed in an oven at 125°C for 12 minutes. A flexible cement layer was obtained, enough firm and flexible to be peeled from the PE foil and rolled. 39506/19

Claims (16)

-16- 270660/ CLAIMS

1. A continuous flexible cement sheet roll for coating construction slabs, the sheet comprising a cement layer having a thickness of between 0.5 and 5 mm and comprising inorganic mortar and up to 15% polymeric binder and further comprising a flexible reinforcing layer that is attached to or embedded in the cement layer and has a thickness that is smaller than the thickness of the cement layer, wherein the flexible reinforcing layer is selected from a film of a nonwoven fabric, a layer of organic or inorganic fibers, a polymer web, a chop strand mat, and a fiberglass mat.

2. The flexible cement sheet roll of claim 1, further comprising a polymeric foil which lines said cement layer.

3. The flexible cement sheet roll of claim 1 or claim 2, wherein said cement layer comprises i) hydraulic cement; ii) sand; iii) water; iv) polymeric binder; and v) up to 10% additives selected from thickeners, fillers, plasticizers, surfactants, dispersants, antifoams, rheology affecting agents, hydrophobicity adjusting agents, and flame retardants (FRs).

4. The flexible cement sheet roll of any one of claims 1 to 3, wherein said cement layer comprises i) 40-70% hydraulic cement; ii) 10-25% sand; iii) up to 10% chalk or calcium carbonate; -17- 270660/ iv) 5-15% water; v) 5-15% polymeric binder; and vi) up to 5% additives selected from thickeners, fillers, plasticizers, surfactants, dispersants, antifoams, rheology affecting agents, hydrophobicity adjusting agents, and FRs.

5. The flexible cement sheet roll of any one of claims 1 to 4, wherein said cement layer comprises i) 50-60% hydraulic cement of Portland types; ii) 13-23% quartz sand; iii) 5-9% chalk or calcium carbonate; iv) 8-12% water; v) 5-9% polymeric binder comprising agents selected from acrylates, styrene acrylic copolymers, styrene and butadiene copolymers, epoxy resins, methyl methacrylate, unsaturated polyester resins, polyurethane, and vinyl esters; and vi) 0.5-5% additives selected from thickeners, fillers, plasticizers, surfactants, dispersants, wetting agents, antifoams, rheology affecting agents, hydrophobicity adjusting agents, and flame retardants (FRs).

6. The flexible cement sheet roll of any one of claim 1 to 5, further comprising a fiberglass mat embedded in said cement layer.

7. The flexible cement sheet roll of any one of claim 1 to 6, further comprising a polymeric foil which lines said cement layer, the foil comprising a nonwoven fabric.

8. The flexible cement sheet roll of any one of claims 1 to 7, for coating construction elements including foamed or extruded polymeric slabs, polystyrene or polyurethane panels, carton slabs, or slabs comprising mineral or organic fibers, wherein the thickness of the cement layer of said flexible cement sheet is a uniform thickness of between 1 and 4 mm, said flexible cement sheet optionally comprises -18- 270660/ a reinforcing layer embedded in said cement layer, and said flexible cement sheet optionally comprises a polymeric foil lining said cement layer, wherein said roll has a width of 0.2-2 m, and said sheet has a length of 50-300 m.

9. A process of manufacturing a continuous flexible cement sheet for coating construction elements, the process comprising i) preparing a cement mortar mixture by homogenizing hydraulic cement, sand, water, 5-15% polymeric binder added to the mixture with a solvent as a fine dispersion, and up to 10% additives comprising agents selected from plasticizers, superplasticizers, antifoams, thickeners, fillers, dispersants, and viscosity adjusting agents; ii) layering said cement mortar mixture onto a heat-resistant surface of a conveyor, the surface optionally covered by a polymeric foil, thereby forming a wet cement mortar layer of a thickness of from 0.5 to 5 mm; iii) embedding in said wet cement mortar layer or attaching thereto - a flexible reinforcing layer of a thickness lower than the thickness of said wet cement mortar layer, selected from a film of a nonwoven fabric, a layer of organic or inorganic fibers, a polymer web, a chop strand mat, and a fiberglass mat; iv) moving said heat resistant surface, optionally with said polymeric foil, bearing said wet cement mortar mixture, optionally with said reinforcing layer, through an oven set at 110-140°C in which said wet cement mixture sets, thereby forming a flexible solid layer; v) peeling said flexible solid layer, optionally with said polymeric foil attached to said flexible layer and lining said flexible layer, from said heat resistant surface, thereby obtaining said continuous flexible cement sheet; vi) rolling said flexible cement sheet up, thereby obtaining a roll of readymade continuous separate cement sheet for immediate or future use in coating construction elements; the continuous sheet being enough strong and flexible to be unfolded and glued on the surface of said construction elements, including foamed or extruded slabs, -19- 270660/ polystyrene or polyurethane panels, carton slabs, slabs comprising mineral or organic fibers, and metal columns or beams.

10. The process of claim 9, wherein the process comprising: i) preparing said homogeneous cement mortar mixture by mixing 35-60% hydraulic cement, 8-20% quartz sand, up to 8% of chalk or calcium carbonate, 15-30% water, 5-15% polymeric binder added to the mixture as a concentrated fine dispersion, and up to 4% additives comprising agents selected from plasticizers, superplasticizers, antifoams, thickeners, fillers, dispersants, surfactants, dispersants, rheology affecting agents, hydrophobicity adjusting agents, FRs, dioctylphthalate, aluminum hydroxide, magnesium hydroxide, cellulose, nylon, fume silica, perlite, vermiculite, glass, PP, basalt, preservatives, and dyes; ii) layering said cement mortar mixture onto said heat-resistant surface, the surface comprising a Teflon surface of a belt conveyor 0.2-2 m wide, optionally covered with said polymeric foil; iii) optionally embedding said reinforcing layer in said wet cement mortar layer, the reinforcing layer comprising fiberglass; iv) moving said heat resistant surface bearing said wet cement mixture optionally with said reinforcing layer into an oven set at 120-130°C, in which said wet cement mortar mixture sets to form said flexible solid layer; v) peeling said layer from said foil, optionally together with said polymeric foil which becomes an integral part of the produced flexible sheet, thereby obtaining said continuous flexible cement sheet; vi) rolling said flexible sheet up, thereby obtaining a roll of continuous cement sheet having a length of 20-200 m for immediate use or for storing for a future use; the continuous sheet being enough strong and flexible to be unfolded and glued onto the surface of said construction elements, including foamed and extruded slabs, polystyrene or polyurethane panels, carton slabs, slabs comprising mineral or -20- 270660/ organic fibers, and metal columns or beams.

11. The process of claim 9 or claim 10, wherein said step iv) is performed in a continuous manner or in a batch manner.

12. The process of any one of claims 9 to 11, wherein said polymeric foil is selected form comprises a nonwoven fabric web.

13. A process for manufacturing a construction composite panel comprising a polymer slab core and a cement coat at least on one side of the slab, the process comprising: i) preparing a cement mortar mixture by homogenizing hydraulic cement, sand, water, 5-15% polymeric binder added to the mixture as a fine dispersion, and up to 10% additives comprising agents selected from plasticizers, superplasticizers, antifoams, thickeners, fillers, dispersants, and viscosity adjusting agents; ii) casting said cement mortar mixture onto a heat-resistant surface of a conveyor, the surface optionally covered by a polymeric foil, thereby forming a wet cement mortar layer of a thickness of from 0.5 to 5 mm; iii) optionally embedding a flexible reinforcing layer of a thickness lower than the thickness of said wet cement mortar layer, selected from a film of a nonwoven fabric, a layer of organic or inorganic fibers, a polymer web, chop strand mat, and fiberglass mat, in said wet cement mortar layer; iv) setting cement mortar layer by exposing it to a temperature of 110-140°C, in a continuous or in a batch manner, thereby providing a solid and flexible cement layer; v) peeling said flexible cement layer, optionally with said polymeric foil, thereby obtaining a continuous flexible cement sheet; vi) folding the sheet to provide a roll of separate readymade flexible cement sheet; vii) applying glue on one side of said slab core or on one side of said flexible cement sheet after unfolding from the coil, and pressing said cement sheet onto said -21- 270660/ core, thereby obtaining a composite panel coated on one side; viii) optionally gluing said flexible cement sheet on the second side of said slab, thereby obtaining a sandwich building composite panel; and ix) clearing and cutting the coated slab to desired shape and size; thereby obtaining structure elements coated on one or two sides, including sandwich-structured polystyrene panels coated on both sides.

14. The flexible cement sheet roll of claim 8, wherein said flexible cement sheet comprises the reinforcing layer embedded in said cement layer.

15. The flexible cement sheet roll of claim 8, wherein said flexible cement sheet comprises the polymeric foil lining said cement layer, wherein said roll has a width of 0.2-2 m, and said sheet has a length of 50-300 m.

16. The flexible cement sheet roll of claim 8, wherein said flexible cement sheet comprises both the reinforcing layer embedded in said cement layer, and the polymeric foil lining said cement layer, wherein said roll has a width of 0.2-2 m, and said sheet has a length of 50-300 m.