EP4326802A1

EP4326802A1 - Rigid panel for construction with central foamed layer and resin coating

Info

Publication number: EP4326802A1
Application number: EP22718309.2A
Authority: EP
Inventors: Nicola Busatta; Paolo Busatta; Federico Cais
Original assignee: Tema Tech and Materials Srl; Tema Technologies and Materials SRL
Current assignee: Tema Tech and Materials Srl; Tema Technologies and Materials SRL
Priority date: 2021-04-21
Filing date: 2022-04-14
Publication date: 2024-02-28
Also published as: WO2022224098A1; IT202100010037A1

Abstract

Rigid panel for construction (10), of the multi-layer type, made up of a central layer (101) in XPS polystyrene or expanded polyurethane, and of an outer layer (102a, 102b), structurally cooperating, in a particular two-component polyurethane resin (A1- A12, B1). They (102a, 102b) are combined in an integral and symmetrical way to the two opposite faces of the central layer (101), a layer on each face, being directly formed thereon with equal thickness and formulation, so as to obtain a rigid panel (10) provided with a high resistance to bending, impacts, damp and also able to support the direct grab of glues or cement mortars. The panel is usable as an element for building walls, infill walls, floors or subfloors, it supports the direct laying of tiles or plasters, and it is suitable for damp environments as in the case of bathrooms, saunas, laundry rooms or kitchens.

Description

RIGID PANEL FOR CONSTRUCTION WITH CENTRAL FOAMED

LAYER AND RESIN COATING

[0001] The present invention relates to a rigid panel for construction with central foamed layer and resin coating.

Field of application

[0002] The invention is intended for use in the building industry and particularly in the sector of semi-finished components for construction such as, by way of non- limiting example, insulating panels and constructive elements of walls and subfloors. More in detail, a lightweight self-supporting panel of the sandwich type is proposed, which is made up of a core in a foamed insulating material such as polystyrene, both expanded and extruded and otherwise called by the acronym XPS (extruded polystyrene insulation), or expanded only and otherwise called by the acronym EPS, or such as polyurethane otherwise called by the acronym PIR or PUR, with a particular outer coating layer which makes it rigid, resistant to bending and damp, and also provided with a good adhesion to glues and/or cement mortars. The proposed panel is usable as constructive element for interior architecture, instead of conventional bricks made of clay or cement, also acting as a support for the gluing of tiles in damp environments as in the case of bathrooms, saunas, laundry rooms or kitchens. By way of example only it is suitable for making walls, floors and/or spaces for the insertion of bathtubs and showers, or seats or niches integrated in the walls of modem bathrooms coated with ceramic tiles.

[0003] In the industrial sector of semi-finished products for construction, panels for thermal insulation, otherwise called non-conductive or insulating panels, are widely known and widespread, which are made up of an inexpensive rigid material, having an extremely low weight but a highly non-conductive performance such as expanded polystyrene or extruded polystyrene, otherwise called by the acronyms EPS and XPS. Generally, said EPS or XPS panels are single-layer panels-and their opposite main faces are smooth and parallel one another, having constant thickness; some solutions provide the outer main faces coated with a protective film in different materials, such as for example a paper sheet or a plastic plate or a non-woven fabric.

[0004] Alternatively, insulating panels made up of a rigid foam obtained with other foam materials, are known and widespread, which sometimes offer a good insulating performance, but are sometimes disadvantageous due to some mechanical characteristics, of resistance to bending or damp, of long-term durability and/or for production reasons. By way of example only, it is reminded that expanded polyurethane, offers a good insulation capacity, but it has to be adequately protected, since it is characterized by a resistance to water and vapor which can be inadequate in particular applications. However, EPS or XPS panels are mostly required not only for the advantageous characteristics of resistance and versatility, but also because in the production phase they require a considerably lower quantity of primary energy; moreover, they are easily recyclable.

[0005] In principle, in the construction field there is currently a higher need for increasing the thermal insulation; this is due to reasons of living comfort and of energy saving, as it is also required by stricter regulations in such sense. Insulating panels made of EPS or XPS are widely used at the extrados of the vertical walls and also in the interspaces between wall partitions, in floor slabs and in roof pitches; particularly, XPS panels have a structure with perfectly closed and uniform cells and are more suitable where a high thermo-insulating capacity is required also in combination with compressive strength and/or water repellency, such as for example in the case of underground rooms or inverted roofs.

[0006] More in detail, it has been found that said expanded EPS, or expanded- extruded XPS polystyrene is extremely advantageous for various aspects: for performance, productive, economical, and recyclability aspects; however, it has some problems when it is used as material for building panels for construction, according to the specific aims of the present invention. A first problem concerns its poor resistance when used with structural functions, such as a constructive element of walls, partitions, infill walls or as support for ceramic coatings, plasters, or any surface finishing for environments. In fact, a conventional EPS or XPS panel has a low resistance to bending and to damp and has a surface which is not suitable for the grab of glues or cement mortars commonly used. It has been then found that its surface tends to crumble or crash when accidentally under bending stress in construction sites, or during transport. A further problem concerns its limited resistance to fire and to high temperatures; despite being treated with flame retardants, when subject to high temperatures a similar manufacture sublimates and loses its structural integrity.

[0007] Generally, in order to overcome such disadvantages, in conventional and known solutions, said EPS or XPS panels are covered with the cited protective films, such as a paper sheet or a plastic plate or a non-woven fabric. Additional layers are also known, which are fire resistant, non-flammable or anyway able to retard combustion; by way of example only, in the vertical walls of buildings such protective layers are made of plasterboard, fiber cement, magnesium oxide, wood - cement or made with a layer in rock or glass wool so as to completely coat the panel or at least its side edges, since they are the preferred combustion priming zone. Protective sheets made of metal or cement are also known, which are applied on the outer surface of the panel. However, it is known that manufactures made with such added layers have a high thickness, a remarkable specific weight, difficulties of working and cutting, hygroscopicity, poor dimensional stability, low tensile strength, and high costs.

[0008] Recently, companies operating in the construction sector have provided to improve said insulating panels in expanded or extruded polystyrene by means of new additive chemical compounds, or of innovative outer protective layers, so as to further increase the thermal insulation characteristics or to reduce the thickness and also, in particular, to improve the fire reaction capacity so as to exceed the latest provisions. By way of example only, expanded polystyrene comprising graphite particles is known, which is suitable for offering a reduced thermal conductivity, limiting the thickness provided for insulation, and is also suitable for absorbing and reflecting infrared rays, such as the material marketed under the name Neopor® of the German company Basf SE, Ludwigshafen - www.basf.com, having a thermal conductivity of 0.031 W/mK and a density of 18 kg/m³. Furthermore, the use of a particular type of graphite is also known, which is called expandable graphite, which increases its volume at high temperatures, creating a protection barrier against fire; it is sometimes added in varnishes or adhesives.

[0009] Furthermore, professionals working in the specific sector of interior architecture have a need for new materials and/or constructive elements suitable for rapidly making walls and subfloors with reduced weights and costs compared to traditional materials such as bricks made of clay or cement, or compared to the reinforced concrete works, or also compared to the conventional plasterboard panels. Particularly, there is a need for versatile and lightweight constructive elements, shaped like rigid and thin panels, provided with a high resistance to bending and damp; moreover, panels are required which are able to ensure a good adhesion to glues and cement mortars. [0010] Essentially, there is a need for a self-supporting panel, which is easy to transport and cut in the construction site by a single person according to need, this panel being rigid and suitable for supporting the laying of tiles, also in the presence of water and/or damp. The aim is to make in an easier and more inexpensive way compared to said bricks and also in a safer and more durable way compared to conventional plasterboard, any configuration of wall, niche, shaped space, floor or subfloor located in damp environments and coated with tiles, as in the case of bathrooms, saunas, laundry rooms and kitchens. By way of example only, it should be taken into consideration the frequent need to obtain spaces for the insertion of bathtubs and showers in bathrooms, or niches integrated in the walls, where said spaces and niches are made in the construction site according to a design provided by the designer, in line with the side walls and coated with the same tiles. Together with said requirements, there is also a need for an insulating panel for damp environments, which can be directly coated with tiles.

[0011] Therefore it has been found that in the market of semi-finished products for construction there are currently no panels able to satisfy all the aforementioned characteristics simultaneously taken into consideration, according to the different aims of the invention, and which are also structurally simplified so as to facilitate the industrial production and to reduce the total costs. Particularly, among the most widespread and advantageous known solutions there are multifunctional insulating panels made up of a foamed core in a lightweight insulating material, such as expanded polystyrene or expanded polyurethane, with a waterproofing and hardening multi-layer coating which is symmetrically glued on both faces, like a sandwich panel. Generally, such superficial coating is made up of various layers having diversified functions and being combined one another, so as to obtain an insulating panel which is resistant to damp and bending and it is usable as a constructive element to make up infill walls, niches or floors, also in damp environments such as bathrooms and saunas. Particularly, some panels provide an external coating which improves the grab of glues or cement mortars, so as to support the gluing of tiles or plasters directly laid on the panel surface.

[0012] Therefore, it has been found that in this advanced type of panels, said multi layer coating consists of at least one waterproof layer, such as a plastic plate or a waterproof paper, which is coupled to permeable layers facilitating the gluing and also increasing the structural rigidity, such as for example a non-woven fabric or a net. By way of example only, it is reminded that the multi-layer panel named Kerdi Board by the German company Schluter-Systems KG, D-58640 Iserlohn www.schlueter.de, is suitable for making bathrooms and shower spaces. Generally, a first permeable layer is joined in adhesion to the foamed core by means of an adhesive material, while the other is placed on the outside to facilitate the anchorage of glues or cement mortars for tiles or plasters; solutions are also known wherein such layers are inverted or there are additional layers.

[0013] Currently, this type of insulating panels with structural function for damp environments is widely used and appreciated as it considerably facilitates the work in the construction site compared to traditional materials, such as clay bricks and plasterboard. However, it is also known to the operators of the sector that they have considerable costs mainly due to their building complexity, being said coating individually made up of two, three or more different layers, which are pre-coupled one another with adhesives or are hot rolled and then they are joined to the foamed core with an additional adhesive layer. Essentially, it has been found that the complex structural configuration of these multifunctional panels is not optimized to industrial and production aims, the coating and the consequent method for its production and application to the foamed core being improvable.

[0014] Other solutions are also known and widespread for making walls, partitions or floors in the internal environments of buildings; for example, rigid sheets made of plasterboard or of cement-based materials are to be noted, which can be provided with external coating layers according to need. However, such sheets are not suitable for the aim of the invention, being disadvantageous during transport and working in the construction site, due to their heavy weight and the dust released during the cutting phase; moreover, they are not very suitable for installations in damp environments, such as bathrooms and laundry rooms where water is frequently present. By way of example only, it has to be considered the making of shower spaces or bathtub coatings.

[0015] Given the above, in the construction sector new insulating panels are required of the sandwich type with a central layer in a foamed insulating material and with a protective coating, which are more advantageous compared to all known and conventional solutions being contextually rigid, resistant to bending and damp, inexpensive to produce, and particularly provided with an outer surface allowing the direct grab of glues and/or cement mortars without primer, nets or interposed layers, so as to reduce time and costs for completing a construction manufacture. In particular, an innovative panel is not known and is desirable which is provided with a single-layer rigid coating, directly formed on the foamed core without interposed adhesive layers, said panel being industrially producible in continuous cycle with high production volumes and considerably reduced costs.

State of the art [0016] In order to determine the state of the art related to the proposed solution, a conventional verification has been carried out examining public archives, which led to the identification of the prior art cited below:

Dl: WO2014131912A1 (Berger et al.)

D2: EP2762522B1 (Burgeth et al.) D3: W09633866 (Atevic)

D4: WO2017189453A1 (Hossieny et al.)

D5: US2011217516 (Wedi)

D6: ES2244318B1 (Asumendi et al.) [0017] Generally the use of resins is known, such as epoxy resins and polyurethane resins with the addition of charge of the silica or sand type, to externally coat lightweight and/or insulating panels based on expanded polystyrene and/or polyurethane with the particular function of thermal or fireproof barrier. For example, Dl proposes an insulating panel in expanded polystyrene provided with a coating for fire protection in a resin of the epoxy type, which is obtained by a polymerization reaction of a mixture made up of a first compound including liquid epoxy resin, ammonium polyphosphate, and other components such as pentaerythritol or pentaerythritol-based esters and polyols, and of a second compound with at least one hardener for epoxy resins. D2 describes a thermal or acoustic insulating panel which is provided with a coating layer having a thickness of between 0.2 mm and 1 mm, which comprises an organic and/or inorganic binder and with 45% of charge weight containing water in the form of crystal and/or hydrate, such as a metallic hydroxide, a hydrate of a metallic silicate, a metallic salt, a metallic sulfate and a possible additive including a pigment, a dye, fibers and/or a flame retardant.

[0018] D3 proposes a multi-layer laminated structure with improved characteristics of fire resistance, which provides a central layer of an insulating material and protective coating layers on both opposite faces like a sandwich panel; they comprise a fibrous reinforcement which is joined with an adhesive layer of the inorganic type and an external layer of an organic resin, wherein said adhesive layer is made of water, magnesium sulphate or magnesium chloride, magnesium oxide and sodium silicate, whereas said resin is a gel-coat based on polyester resin modified with aluminum hydroxide.

[0019] D4, instead, describes the structure of a thermal insulating panel in a polymeric foam, with an external coating of the multi-layer type which is provided with an excellent thermal stability being made up of a first layer of the non-cellular type in a heatproof thermoplastic material, and of a second non-cellular layer in a polylactic acid- based resin which acts as barrier, being able to reduce the loss of insulating capacity due to the progressive replacement of the expanding agents of the internal foam with atmospheric gases.

[0020] Generally, sandwich panels are also known with a foamed core and a coating in glass fiber; for example, D5 proposes a panel for construction in XPS with a multi-layer coating wherein the first layer contacts the foamed core and consists of a two-component epoxy resin on which fiberglass is sprayed so as to form an intermediate layer of casually placed and flattened fibers, and with a smooth top layer of a two-component epoxy resin.

[0021] D6 describes, instead, a multi-layer building panel, usable as a constructive element of walls, partitions, or false ceilings, which is made up of a very lightweight core in expanded polystyrene or polyurethane coated with a resistant layer made with a resin directly applied on said core in combination with a catalyst and with particular charges, such as silica sand, corundum, crushed glass or silicon carbide. Drawbacks

[0022] It has been found that the known and conventional solutions mainly used of insulating panels for construction with also structural function, suitable for damp environments, are advantageous in the laying but have high costs; in particular, the cited panels of the sandwich type with the core in a foamed insulating material and with thin multi-layer coatings and consisting of waterproof films, papers, nets and/or non-woven fabrics, use expensive semi-finished products, which require various production phases with also interposed glue layers. Instead, it is not known and is desirable an innovative solution of panel for construction having similar functions but being more inexpensive and easier to produce, wherein the protective coating is in a single-layer and multifunctional, and it is directly formed and/or applied in a continuous production line, without interposed layers for the adhesion to the foamed core and without superposed layers for the grab of the tiles. In particular, a simplified structure of panel is not known and is desirable with a cooperating and rigid single-layer coating, suitable for damp environments, which contextually ensures an excellent resistance to bending, to damp, and also to high temperatures, and which is easy and clean during working in the construction site, and furthermore it is provided with an outer surface compatible with the common glues and/or cement mortars for tiles, directly acting as grab interface. Instead, in the current solutions all these functions are performed by various layers, each time coupled one on the other according to their function.

[0023] In principle, it has also been found that one resin layer directly applied to the insulating panel can be useful and advantageous for the aims of the present invention, having a rigid consistency and also being able to protect from high temperatures. However, known solutions with at least one resin layer or with other compounds pre-formed in sheets or directly applied, provide complex working and/or disadvantageous materials. For example, the panels in glass fiber or with epoxy-based resins are considered obsolete due to their overall manufacturing costs, due to complex working and equipment and/or due to some dangerous ingredients, such as for example pentaerythritol according to D1 or polyester resin in D3. Moreover, it is known that panels with aggregates and/or sulfate or magnesium oxide are very heavy and have a floury consistency, being therefore dusty and not very clean for works in indoor environments. It is also known that polyester rapidly degrades in an alkaline environment, tending to saponify, as it could occur for the use intended by the present invention with direct application of a cement mortar for tiles or plasters.

[0024] Moreover, said economical and productive disadvantages in multi-layer solutions are to be reminded, such as for example in D3 or D4; furthermore, it has also been found that solutions of panels having a complex structure or which provide additional operations in the coating application, such as for example in D5 or D6, do not allow an easy continuous production, as, instead, it is currently desirable in a modem automated industrial production with low costs and high production volumes.

Summary of the invention [0025] This and other aims are achieved by the present invention according to the characteristics of the appended claims, solving the exposed problems by means of a rigid panel for construction (10) of the multi-layer type, made up of a central layer (101) in XPS polystyrene or expanded polyurethane, and of an outer layer (102a, 102b) structurally cooperating in a particular two-component polyurethane resin (Al- A12, Bl). These (102a, 102b) are joined in an integral and symmetrical way at two opposite faces of the central layer (101), a layer on each face, being directly formed thereon with equal thickness and formulation, so as to obtain a rigid panel (10) provided with a high resistance to bending, impacts, damp and which is also suitable for supporting the direct grab of glues or cement mortars. The panel is usable as a constructive element for walls, infdl walls, floors or subfloors, it supports the direct laying of tiles or plasters, and it is suitable for damp environments as in the case of bathrooms, saunas, laundry rooms or kitchens.

Aims [0026] In this way, through the considerable creative contribution whose effect constitutes an immediate technical progress, several advantages are achieved.

[0027] A first aim is to obtain an insulating panel for construction which is extremely resistant, rigid and self-supporting, so as to be usable as a constructive element for building in an easy and inexpensive way the different structures and the completion works, which are currently needed in modem interior architecture. For example, it is suitable for building walls, partitions, infill walls, floors, subfloors, shower spaces and niches, it is suitable for making in an easy and inexpensive way the different structures and the completion works, which are currently needed in the modem interior architecture. [0028] A second aim is to obtain a rigid panel for construction, which also acts as barrier to vapor.

[0029] A third aim is to obtain a rigid panel for construction which is provided with an outer surface ready for the finishing and compatible with cement mortar. In fact, on said panel common ceramic coatings, or any finishing tile or plaster, can be directly applied by using glues or cement mortars of the conventional and known type, without the need for interposing any film, net, grab primer or any material to facilitate the adhesion. Moreover, a rigid coating layer is provided, which can be superficially worked during the production phase, so as to further increase the resistance to tearing of glues or cement mortars. The proposed solution considerably facilitates the work in the construction site and allows to considerably reduce time and costs for completing a construction manufacture.

[0030] A fourth aim is to obtain a rigid panel for construction, which is easy to transport, to place and to work in the construction site by a single operator using the common working tools without releasing dusts in the environment. [0031] A fifth aim of this invention is to make a multi-layer panel having an optimized structural configuration, being made up of a minimum number of layers, and namely only three layers which are symmetrically joined without interposed glues, using only one material for the foamed core and only one material for the coating; said configuration being suitable for the continuous industrial production with high production volumes, high repeatability and end quality, and with considerably reduced costs.

[0032] A sixth aim is to obtain a rigid panel for construction in XPS polystyrene or expanded polyurethane, which is also provided with a good resistance to fire. [0033] Moreover, an aim is also to avoid the above-mentioned drawbacks with an innovative panel for construction, which allows to contextually obtain all the above-mentioned advantages, and which is therefore versatile in use, and it also considerably facilitates the work in the construction site, the material procurement and the transport. Essentially, a thin panel like a sheet is proposed in a foamed material with faces coated of a thin rigid layer, structurally cooperating, obtaining a constructive element, which is provided with a high resistance to bending and to impacts, it is self-supporting despite having a limited weight, it has reduced production costs, it can be worked in the construction site like any panel for thermal insulation, it can be directly coated with tiles or plaster, and it is also usable in damp environments as it is unaffected by water or damp. Therefore, consequently to what described above, an innovative panel for construction has to be made with a single-layer coating, which can be produced in an inexpensive way with equipment for continuous production and which has excellent performance characteristics which are advantageously combined one another, being contextually provided with a high resistance to bending, a high resistance to vapor permeability and to damp, a high compressive strength, a high resistance to tearing also called pull-out with reference to the grab of glues and/or cement mortars, in addition to a good resistance to high temperatures. [0034] These and other advantages are evident from the following detailed description of a preferred embodiment with the aid of the enclosed schematic drawings whose details are not to be intended as limiting but only exemplary. Content of the drawings

Figure 1 represents the rigid panel for construction, which is the subject matter of the present invention, in a detailed schematic section not to scale.

Figure 2 represents the same panel of the previous figure, mounted in adhesion on a load-bearing structure and with tiles directly glued on the front face, in a detailed schematic section not to scale.

Figure 3 represents a different embodiment of the invention, of Figure 1, wherein the front face of the panel has a uniform surface abrasion which increases the grab of glues or cement mortars. Practical realization of the subject matter of the invention

[0035] Also with reference to the figures (Figs. 1, 2, 3), a rigid panel for construction (10) is proposed of the insulating and self-supporting type, suitable for contextually performing various functions; it is a lightweight panel for thermal insulation, provided with a high rigidity and resistance to bending, which acts as flat constructive element suitable for making walls, infill walls, floors or subfloors, and which is also suitable for protection against vapor and damp. In particular, said panel properly supports the laying of tiles, directly glued on its outer surface by means of glues or cement mortars commonly used, without the need for interposing a primer layer, a fabric or a net for the grab; therefore, it allows to lay thin tiles of the cement or ceramic type, but it is also suitable for the grab of cement- based plasters or other directly applied finishing.

[0036] The proposed panel (10) considerably facilitates the completion works in indoor environments of buildings, and it is particularly suitable for damp environments with vapor and/or water such as bathrooms, saunas, laundry rooms or kitchens; for example, it (10) allows a single operator to rapidly and inexpensively build a whole bathroom coated with ceramic tiles and provided with articulated volumes such as the shower space and wall niches. In a typical installation in a damp environment with the aims of coating and waterproofing, the panel (10) can be fixed in adhesion to a load-bearing structure (201) such as a masonry or a floor slab, or to a partition of plasterboard or wood, or to any other structure, and on its front face (102a, 103a) a layer of tiles (202) can be directly glued by means of an adhesive layer (203) of a common glue or cement mortar with the conventional grout lines (204) of tile finishing (Fig. 2). Such a solution does not need other materials or additional working.

[0037] The proposed panel (10) presents a symmetrical sandwich structure which is extremely lightweight and resistant, consisting of only three total layers (101, 102a, 102b), wherein a central layer (101) is made of a foamed material and acts as a lightweight, insulating core, while the two outer layers (102a, 102b) act as rigid coating and are made of a particular resin. These (102a, 102b) are respectively joined at the two opposite faces (103a, 103b) of said central layer in an integral way with only one layer for each face (Fig. 1). The central layer (101) has a constant thickness (SI) of between 4 mm and 200 mm, with a density of between 15 Kg and 50 Kg/m³; in the preferred embodiment of the invention, said central layer has a constant thickness (SI) of between 6 mm and 50 mm with a density of 25 Kg/m³ with a tolerance of ± 20%. Instead, each outer layer (102a, 102b) has a constant thickness (S2) of between 0.2 mm and 5 mm, with a density or a specific weight higher than 1000 Kg/m³; in the preferred embodiment of the invention, each outer layer has a constant thickness (S2) of between 0.2 mm and 1 mm, with a density or a specific weight of 1500 Kg/m³ with a tolerance of ± 2%. In the preferred embodiment a finished panel (10) has a total thickness (S3) of between 6.4 mm and 52 cm; however other values are suitable for the proposed panel depending on a specific application.

[0038] Said central layer (101) is preferably made up of expanded and extruded polystyrene, which is otherwise called by the acronym XPS, or it is made of expanded polyurethane; such materials ensure the maximum structural homogeneity of the foamed core, with regular cells and without discontinuity, they are then compatible with the resin provided for the coating and also facilitate the production on a continuous line. However, alternatively to the above-mentioned insulating materials, other materials can be used having the same characteristics, equivalent to the aims of the invention. Instead, the outer layers (102a, 102b) are made up of a polyurethane resin of the two-component type (A, B), having a particular composition (A1 - A12, Bl) which is rigid on the end product but which during the production has a semi-liquid and dense consistency such as a glue, so as to be easily applied on both faces of the foamed central layer (101) in a continuous production line. Through the cross-link said resin hardens, becoming rigid, protective, and structurally cooperative according to the aims of the invention, so as to act as structural reinforcement, as protection both against damp and impacts, and as grab interface. [0039] The outer layers (102a, 102b) are joined in an integral and symmetrical way to the central layer (101), the resin being directly applied on both its faces (101, 103a, 103b) with equal thickness and formulation, without adhesives or any interposed layer, so as to obtain an optimized sandwich structure, which is industrially producible at low costs and which has performance characteristics considerably improved with respect to the known and conventional solutions. In particular, it is clarified that the resistance values described hereinafter and also cited in the first claim, are typical of a rigid panel for construction (10) made as provided by the present invention (101, 102a, 102b, A1 - A12, Bl) and have to be intended as referring to the expressly indicated regulations and/or to the expressly indicated measuring methods; in fact, said panel (10) is contextually provided with: a) a resistance to bending of a minimum value of 200 N in correspondence with a deformation of 4 mm, according to ASTM C947-03 regulation; b) a resistance to vapor permeability of a maximum value of 3% of passage of vapor after staying in a stove at 90°C for 24 hours; c) a compressive strength of a minimum value of 200 kN/m², according to ASTM D 1621-16 regulation; d) a resistance to tearing or pull-out of a minimum value of 0.4 n/mm², according to UNI EN 1348 regulation. [0040] It is noted that such characteristics of resistance are obtained because of the optimized configuration of the invention (10, 101, 102a, 102b) and of the particular composition of said resin, which comprises two groups of components (A, B), wherein a first group (A1 - A 12) comprises in turn at least three different polyols (Al, A2, A3) combined to at least one mineral charge (A4), to a porous material acting as a molecular sieve (A5) and to other completion materials (A6 - A 12) such as excipients (A6), dampeners (A7), stabilizers (A8), reagents (A9), antifoam (A10), dispersions (All) and oxides (A12); the second group (B), instead, comprises at least one stabilized polymeric isocyanate (Bl) for the expansion.

[0041] More in detail of said polyols (Al, A2, A3) a first vegetal polyol is provided with a high content of triglycerides (Al), a second polyol with two hydroxyl groups or diol (A2) and a third polyol with three hydroxyl groups or triol, acting as crosslinker reagent (A3); in particular, the last triol increases the hardening and the resistance of the resin, by contextually combining to said mineral charge (A4), to said molecular sieve (A5), and to said isocyanate (Bl). Therefore, in the preferred but non-limiting embodiment of the invention said first group (Al - A 12) consists of the following ingredients: a) as vegetal polyol (Al) castor oil is used in a percentage of between 10% and 20% on the total weight; b) as diol (A2) a sugar alcohol is used such as isomaltol or lactitol in a percentage of between 10% and 20% on the total weight; c) as crosslinker reagent (A3) a hygroscopic polyether is used in a percentage of between 10% and 20% on the total weight; d) as mineral charge (A4) a calcium carbonate is used in a percentage of between 10% and 20% on the total weight; e) as molecular sieve (A5) an aluminosilicate is used, such as for example zeolite, having structural cavities or pores, which are uniformly distributed and have a diameter of between 3 angstrom and 10 angstrom and an internal pores surface with an overall area of between 600 m²/g and 700 m²/g, in a percentage of between 10% and 20% on the total weight; f) therefore, said completion materials (A6 - A12) are provided in an overall percentage until the total weight is reached.

[0042] The rigid panel for construction described above (10, 101, 102a, 102b) is suitable for the continuous industrial production with reduced costs and high production volumes, according to a productive process comprising the following steps (FI - F8):

FI) a first phase for making a foamed sheet suitable for forming said central layer (101) of the panel (10), alternatively obtained by means of extrusion and expansion if it is made up of XPS polystyrene, or obtained by means of expansion if it is made up of polyurethane;

F2) a second phase for curing said foamed sheet;

F3) a third phase for cutting in thinner sheets, according to need;

F4) a fourth phase for preparing said resin suitable for forming said outer layers (102a, 102b) of the panel (10), by means of mixing of the different materials which form it (A1 - A 12, Bl) and by keeping it at a temperature between 10°C and 40°C;

F5) a fifth phase for applying said resin on said sheet by means of continuous coating, being said resin simultaneously applied on both sides of sheet only with a single flat passage through an adhesive coating machine; F6) a sixth phase for crosslinking said resin, wherein the resined sheet is left to stand for at least 24 hours from the application;

F7) a seventh phase for finishing, wherein said sheet with crosslinked resin is at least cut to size in finished panels and ready for use by means of a cutting and squaring device at 90°, such as for example a pantograph; F8) an eight phase for packaging and moving said grouped panels, being for example packed in pallets for the transport to the client.

[0043] It is clarified that in said fifth phase (F5) the above-mentioned resin which is properly prepared and mixed (A1-A12, Bl, F4) can be advantageously applied by means of a common machine for the even distribution of glue on any panel or thin sheet, symmetrically and contextually on both opposite faces; it is called coating machine and it is conventionally used in the furnishing industry where it is also called gluing machine, or glue applicator or also glue coater. In particular, it is equipped with a system of doser rollers which are symmetrically present both above and under the panel and allow to adjust the quantity of resin laid down at least according to the rotation speed and to the desired thickness.

[0044] In a first different embodiment of the invention (Fig. 3) suitable for considerably improving the grab interface for said glue or cement mortar of tiles or plasters, at least one of the outer layers (102a, 102b) has the outer surface abraded (104). More in detail, various incisions and/or grooves and/or scratches and/or non- through cavities are provided, and namely of a depth smaller than the thickness of said outer layer, which are uniformly distributed on the whole outer surface, increasing said resistance to tearing or pull-out, so as to obtain a minimum value of 0.5 N/mm². They can be obtained by means of mechanical abrasion from the exterior, on a panel already formed (101, 102a, 102b) through incision and/or localized removal and/or micro-scratching of the material.

[0045] Such abrasion (104) is industrially producible in the same continuous production line where the panel (10, 101, 102a, 102b) is produced. In the preferred embodiment, it is obtained contextually to said seventh phase (F7) of the productive process, with a flat passage of the finished panel through a roller calibrating machine, being said rollers coated with abrasive paper having a FEPA grain number of between P40 and P120; in that case, said calibrating machine is also equipped with an instantaneous dust suction system in order to prevent dust from obstructing localized removals and/or micro-scratchings caused by the abrasive paper. In an alternative embodiment, said abrasion is obtained with a flat passage of the finished panel on a roller conveyor, wherein at least one roll equipped with metallic brushes having thin wires and folded ends, in the form of a hook, insist so as to incise the surface while rotating.

[0046] In a further different embodiment which is not represented in the figures and suitable for considerably increasing the resistance of the panel (10) to high temperatures and/or fire, the outer layers (102a, 102b) are made of a two- component polyurethane resin which also comprises expanding graphite and/or sodium silicate and/or ammonium polyphosphate and/or triethyl phosphate called by the acronym TEP and/or zinc borate, said components being considered individually or in combination with each other in a global concentration of between 1% and 20% on the total weight, for increasing the fire resistance of the panel (10). And still, alternatively to this solution or additionally to it, in order to obtain a greater increase, said central layer (101) is expected to be made of a polymer comprising expanding graphite and/or sodium silicate and/or trichloro propyl phosphate called by the acronym TCPP and/or ammonium polyphosphate and/or brominated compounds, said components being considered individually or in combination with each other in a global concentration of between 1% and 20% on the total weight. It is noted that such a characteristic of fire resistance can be industrially obtained in an easy way and with a limited cost increase, only by adding the above-mentioned ingredients to the composition of said insulating material and/or of the resin (A1 - A12, Bl) described above, without additional layers or any particular working.

[0047] Moreover, in order to increase the fire resistance of the outer layers (102a, 102b) and to avoid collapsing in case of fire, in a variant of the invention not represented in the figures, it is provided that they (102a, 102b) include a small net of fiberglass acting as reinforcement for the resin; to this end, a small net is suitable with a mesh size between a minimum of 5 mm by 5 mm and a maximum of 20 mm by 20 mm. Such a safety solution is suitable both in the case of a resin with additives as described above, and in the case of a resin without additives.

Nomenclature

(10) rigid panel for construction, according to the present invention;

(101) central layer in a foamed insulating material, acting as a core, alternatively made up of expanded and extruded polystyrene also called by the acronym XPS of extruded polystyrene, or in expanded polyurethane;

(102a, 102b) outer coating layer which is protective and structurally cooperating, made up of a particular polyurethane resin of the two-component type with a front layer (102a) and a back layer (102b).

(103a, 103b) main faces of the panel, wherein the front face (103a) acts as grab interface of glues or cement mortars for tiles, plasters or equivalent finishing, while the back face (103b) can be fixed for support to a load-bearing structure or a partition;

(104) superficial mechanical abrasion;

(201) load-bearing structure, such as for example a masonry or a floor slab, or a partition in plasterboard or wood; (202) tile, in a ceramic material with a thin thickness or equivalent;

(203) adhesive layer for laying, in a glue or a cement mortar for tiles;

(204) finishing grout-line between tiles.

Claims

1. A rigid panel (10) for construction, of the multi-layer type, insulating and self-supporting, which can be used as a constructive element of walls, infill walls, floors or subfloors, it resists to bending and to humidity, and it is suitable for damp environments such as bathrooms, saunas, laundry rooms or kitchens; said rigid panel (10), being suitable for supporting the laying of tiles (202), plasters or similar coating materials; said rigid panel (10), made up of a central foamed layer (101), which alternatively is made up of expanded and extruded polystyrene called XPS, or of expanded polyurethane, and of two outer layers (102a, 102b) made up of a polyurethane resin acting as a coating; said outer layers (102a, 102b), respectively combined with the two opposite faces of said central layer (101), a single layer for each face (102a, 103a) (102b, 103b), forming a three-layer sandwich panel (102a, 101, 102b); said rigid panel (10), characterized in that the outer layers (102a, 102b) are made up of polyurethane resin of the two-component type (A, B) wherein a first group (A1 - A12) includes at least three different polyols (Al, A2, A3) combined with at least one mineral charge (A4), a porous material acting as molecular sieve (A5) and completion materials (A6 - A12), while a second group (B) includes a stabilized polymeric isocyanate (Bl); said polyols (Al, A2; A3), being a vegetal polyol with a high content of triglycerides (Al), a polyol with two hydroxy lie groups or diol (A2) and a polyol with three hydroxylic groups or triol acting as crosslinker reagent (A3) which increases the hardening and the resistance of the resin combining with said mineral charge (A4), to said molecular sieve (A5) and to said isocyanate (Bl); said outer layers (102a, 102b), combined in an integral and symmetrical way with said central layer (101) being said resin (A1 - A12, Bl) directly applied on both its faces (101, 103a, 103b) with equal thickness and formulation (A1 - A12, Bl); and wherein said outer layers (102a, 102b) in said resin (A1 - A12, Bl) act as structural reinforcement, as protection against damp, as protection against impacts and as adhesion interface, in such a way that said rigid panel (10) contextually has a resistance to bending of at least 200 N in correspondence with a deformation of 4 mm, a resistance to vapor transmission by up to 3%, a resistance to compression of at least 200 kN/sqm, and a resistance to tearing or pull- out of at least 0,4 N/sqmm.

2. A rigid panel (10) for construction, according to claim 1, characterized in that said vegetal polyol (Al) is castor oil, in a percentage of between 10% and 20% on the total weight; and wherein said diol (A2) is a sugar alcohol such as isomaltol or lactitol, in a percentage of between 10% and 20% on the total weight; and wherein said crosslinker reagent (A3) is hygroscopic polyether, in a percentage of between 10% and 20% on the total weight; and wherein said mineral charge (A4) is a calcium carbonate, in a percentage of between 10% and 20% on the total weight; and wherein said molecular sieve (A5) is an aluminosilicate such as zeolite, having structural cavities or pores that are uniformly distributed and a diameter of between 3 angstrom and 10 angstrom and an internal pores surface with an overall area of between 600 sqm/g and 700 sqm/g, in a percentage of between 10% and 20% on the total weight; and wherein said completion materials (A6 - A12) are: excipients (A6), dampeners (A7), stabilizer (A8), reagents (A9), antifoam (A10), dispersions (All) and oxides (A12), in an overall percentage until the total weight is reached.

3. A rigid panel (10) for construction, according to claim 2, characterized in that said central layer (101) has a constant thickness (SI) of between 4 mm and 200 mm, with a density of between 15 Kg and 50 kg per cubic meter; and wherein each outer layer (102a, 102b) has a constant thickness (S2) and of between 0,1 mm and 5 mm, with a density higher than 1000 kg per cubic meter.

4. A rigid panel (10) for construction, according to claim 2, characterized in that said central layer (101) has a constant thickness (SI) and of between 6 mm and 50 mm, density of about 30 kg per cubic meter, with a tolerance of +/- 10 kg per cubic meter; and wherein each outer layer (102a, 102b) has a constant thickness (S2) and of between 0,2 mm and 1 mm, with a density of 1500 kg per cubic meter considering a tolerance of ± 200 kg per cubic meter.

5. A rigid panel (10) for construction, according to claim 1 or 2 or 3 or 4, characterized in that at least one of said outer layers (102a, 102b) has visibly mechanically abraded surface, with various incisions and/or grooves and/or scratches and/or recesses uniformly distributed on the whole surface and having a depth smaller than the thickness of the same outer layer, in such a way that said resistance to tearing or pull out is at least equal to 0,5 n/sqmm.

6. A rigid panel (10) for construction, according to at least one of the previous claims, characterized in that said outer layers (102a, 102b) are made of a bicomponent polyurethane resin also including expandable graphite and/or sodium silicate and/or ammonium polyphosphate and/or triethyl phosphate called by the acronym TEP and/or zinc borate, said components being considered individually or in combination with each other in a global concentration of between 1 % and 20% on the total weight, for increasing the fire resistance of the panel (10).

7. An insulating panel (10) for construction, according to at least one of the previous claims, characterized in that said outer layers (102a, 102b) include a fiberglass net acting as rebar for the resin; and wherein said net has a mesh size that is of between a minimum of 5 mm by 5 mm and a maximum of 20 mm by 20 mm.

8. A rigid panel (10) for construction, according to at least one of the previous claims, characterized in that said central layer (101) is made up of a polymer also including expandable graphite and/or sodium silicate and/or trichloro propyl phosphate called by the acronym TCPP and/or ammonium polyphosphate and/or brominated polymers, said components being considered individually or in combination with each other in a global concentration of between 1 % and 20% on the total weight, for increasing the fire resistance of the panel (10).

9. Productive process of a rigid panel (10) for construction which is made according to at least one of the previous claims, characterized in that at least the following operative phases (FI - F8) are involved: FI) a first phase for making a foamed sheet suitable for forming said central layer (101) of the panel (10), alternatively obtained by means of extrusion and expansion if it is made up of XPS polystyrene, or obtained by means of expansion if it is made up of polyurethane; F2) a second phase for curing said foamed sheet;

F3) a third phase for cutting in thinner sheets, according to need;

F4) a fourth phase for preparing said resin suitable for forming said outer layers (102a, 102b) of the panel (10) by means of mixing of the different materials that form it (Al - A12, B1) and by keeping it at a temperature of between 10°C and 40°C;

F5) a fifth phase for applying said resin on said sheet by means of continuous coating, being said resin simultaneously applied on both sides of the sheet only with a single flat passage by means of a adhesive coating machine of the type used in the furnishing industry and also called gluing machine or glue applicator or glue coater, wherein said coating machine is equipped with a system of doser rollers which are symmetrically present both above and under the panel and allow to adjust the quantity of resin laid down at least according to the rotation speed and to the desired thickness; F6) a sixth phase for crosslinking said resin, wherein the resined sheet is left to stand for at least 24 hours from the application;

F7) a seventh phase for finishing, wherein said sheet with crosslinked resin is at least cut to size in finished panels and ready for use by means of a cutting and 90°- squaring device, e.g. a pantograph; F8) an eight phase for packaging and moving said grouped panels, being, for example, packed in pallets for the transport to the client.

10. Productive process of a rigid panel (10) for construction, according to claim 5 and 9, characterized in that in said seventh phase (F7), mechanical abrasion is also performed on at least one of said outer resin layers (102a, 102b), in such a way as to form various incisions and/or grooves and/or scratches and/or recesses uniformly distributed.

11. Productive process of a rigid panel (10) for construction, according to claim 10, characterized in that said mechanical abrasion is carried out by means of a flat passage of the finished panel through a roller calibrating machine, wherein said rollers are coated with abrasive paper having a FEPA grain number of between P40 and P120; said calibrating machine, being equipped with an instantaneous dust suction system.

12. Productive process of a rigid panel (10) for construction, according to claim 10, characterized in that said mechanical abrasion is carried out by means of a flat passage of the finished panel on a roller conveyor wherein at least one roll equipped with metallic brushes having thin wires with folded ends, in the form of a hook, insists in such a way as to incise the surface while rotating.