WO2016028179A1 - Self-bearing fibre panel with core made of cork agglomerate - Google Patents

Abstract

The present invention relates to composite panels comprising at least three layers: a thicker layer of a low-density material, the core (2), which is coated with two thin outer layers, the sheets (1), which have a higher density than the core (2). The core (2) is united to the layers (1) by adherence, both by adhesion (of a chemical nature) and by friction (of a physical nature). The sheets (1) are formed by a combination of a thermally hardenable epoxide resin matrix impregnated into one or more fibre glass nettings. The core (2) is formed by a cork agglomerate, which is a product characterised by its low density, considerable stiffness and cut resistance, good thermal insulation and good acoustic insulation. As a result of the combination of the materials used, the present invention provides a light-weight construction panel which makes it possible to build self-bearing walls for building floors having the usual ceiling height, with mechanical characteristics that enable the panel to be used in walls and roofs of buildings, with satisfactory properties when subjected to external influences such as impacts, moisture and fire.

Description

 description

Freestanding fibreboard with cork chipboard core

Cork agglomerate is an organic material which has characteristics capable of good thermal and acoustic insulation and is currently a material commonly applied in the construction industry. It also has very good mechanical characteristics, namely compressive, cohesive and shear strength, especially in view of its low volume weight. This material withstands, without degrading, deforming or undergoing any irreversible change in its properties, use temperature limits within the range usually required for its application to buildings, typically between -180 ° C to + 140 ° C. However, the constitution of cork allows its exposure to extreme temperatures well above these.

Although the cork agglomerate is thermally degraded, it does not melt, that is, it does not completely lose its strength and shape, nor does it loose or leak molten combustible material, possibly flammable. Their combustion does not produce any other high toxicity products in noteworthy quantities other than carbon monoxide generated by the thermal degradation of almost all organic materials. It is also a renewable and 100% natural raw material, subject to a natural, totally recyclable and energy-efficient industrial process. It is produced and marketed in slabs (3, 3 ') of varying thickness and dimension with high water vapor permeability. The compressive strength of these plates allows them to withstand relatively high loads without deforming too much. Its cohesive strength ensures a good ability to withstand tensile forces perpendicular to its main faces. Its considerable The shear strength makes them particularly suitable for resisting the stresses introduced by other materials adhering to the plate surfaces.

The properties of the cork agglomerate also allow the boards to exhibit good dimensional stability even in the face of significant variations in temperature and relative humidity to which they may be subjected.

Cork agglomerate is compatible with most known building materials and may be in contact with them in their current applications. There are no known chemical interaction problems with substances contained in other products, such as plasticizers, solvents, resins, aromatics or hydraulic binders. Therefore, the plates 3, 3 'may be bonded to one another or to other materials with a wide variety of adhesives and other binders.

In the form of slabs (usually less than 2m ^{2 in size} ), it is currently used in buildings as exterior wall insulation, as facade cladding, as double-walled insulation in air boxes and flat roofs, as thermal insulation. roofs, attics and ground floors, as insulation in the transmission of rebound and anti-vibration noise from machines and as thermal insulation of cold rooms.

Despite all these features, existing corkboard panels do not have sufficient strength to withstand the compressive stresses required on a self-supporting wall, and as such have been mainly used as flooring and thermal and acoustic insulation materials.

In order to overcome this problem, it was considered to add another material to the traditional chipboard panels. cork, which material which together with the cork agglomerate could increase the strength of the panel to the desired levels, thus emerging the present invention.

Subject of the Invention

The present invention relates to cork agglomerate core laminated composite panels, which core is covered on its two largest surfaces by two blades resulting from the combination of a thermosetting epoxide resin matrix with one or more meshes. Fiberglass More particularly the invention relates to cork agglomerate core composite fibrous panels whose mechanical properties allow them to be used as self-supporting structural panels.

The invention can be applied in the construction of self-supporting walls for constructions of a standard ceiling floor, with mechanical characteristics that allow its application in building walls and ceilings, behaving properly when subjected to external actions. Additionally, in the construction of self-supporting walls, the present invention has sufficient bending and shear strength (for loading perpendicular to its larger faces) to be simply attached to the base and top, requiring no additional structure of bracket or locking element. It also has sufficient axial compressive strength (parallel to the plane of the faces) to withstand loads of the order of those transmitted to it by its supporting ceilings. Finally, it should be noted that it has bending resistance to cut suitable for its use as a roof closure material. Background of the Invention

Current prefabrication systems in the housing sector are mostly characterized by heavy solutions that are difficult to handle and require the use of equipment for installation.

The weight of these solutions most often results from the need for their constituent elements to have the dual function of ensuring the structural resistance of the building to the mechanical actions that require them, and of ensuring that the space enclosing them has the desired acoustic behavior characteristics. , thermal and hygrometric to serve as housing (or any other use that may be given). In addition to these, these elements have to withstand other physical actions - such as fire, for example - and / or chemicals - such as resistance to exposure to the environment.

Historically it has been found that the inclusion of these properties in one material, or in the combination of two or more materials, results in heavy and demanding constructive solutions in terms of energy resources and expenditure.

Indeed, if one removes - in whole or in part - the building elements that surround the areas where the responsibility for supporting the overlying elements resides, the range of materials available that can meet all other requirements greatly increases. In addition, materials are available that until today were not seen as buildable, but only cladding and therefore required any other subsidiary material or system to structure them.

Ideally, a system is desired where the supporting structure of the building is independent of walls, ceilings and floors, so that they can be made of easy-to-assemble elements, put to work by lifting means that take advantage of the building's pre-built structure, ie the structure itself will function as a "crane" for the construction, allowing huge savings on site and offering a solution for future building maintenance.

The application of prefabricated lightweight panels, where their size is only limited by the way they are transported from factory to site, and the weight of each panel - compatible with two to three workers' handling - within a formulation The modular structure of the entire building - systems, installations and structures included - is the ideal solution for the construction of walls and ceilings, with economic gains associated with the speed of execution.

There are several solutions to this problem on the market today, namely modular panels composed of one or more materials. However, until today, it was not possible to make self-supporting panels consisting mainly of cork agglomerate.

In the form of slabs, cork agglomerate is currently used in buildings as exterior wall insulation, facade cladding, double-walled insulation in flat boxes and flat roofs, as thermal insulation of roofs, attics and ground floors, as insulation in the transmission of reverberation and anti-vibration noise from machines and as thermal insulation of cold rooms.

Until now, existing solutions in the state of the art do not provide satisfactory solutions that combine cork characteristics with mechanical, structural and self-supporting characteristics. The present invention is the only one where cork is incorporated into a self-adhesive composite laminate panel. therefore. To support this statement, below are some examples of prior art cork panels.

Amorim Cork Composites, S.A. Patent Published PT105013 A, published on 2011/09/16, entitled "Ceramic Laminate with Cork and Fiber", discloses a fiber-compatible ceramic and cork laminate for use in flooring. In this document, cork is used as an insulating material and the laminate serves as a coating material and does not impart overall structural properties.

Daishin KK and Phoenix KK Patent JPF01244065 A, published on 1989/09/28, entitled "Vibration and Sound Proof Composite Board", discloses a panel consisting of, among others, cork, viscous foam and wood particles for used for sound insulation and vibration reduction. Likewise, in this document the panel is used only as a cover and throughout the document it is never disclosed or suggested that the panel has the mechanical characteristics necessary to function as a self supporting panel.

Patent Application O2006030041 A1 to Daniel Conca Carnus, published on 2006/03/23, entitled "Floor and Wall Covering Element", discloses a two-layer wall or floor covering panel, a sturdy ceramic topsheet, stoneware, marble, granite or the like; and a lower layer in material with a high thermal / acoustic coefficient, such as cork or polyurethane foam. The layers are joined by an adhesive. In this case, and as the title of this document indicates, the panel containing the cork is only a covering and cannot be used as a self supporting wall if it does not have a supporting structure attached. Contrary to the examples cited, in the present invention the cork agglomerate is not used to coat another material, but it is the cork agglomerate itself that forms the inner core of the laminated panel, and occupies the bulk of the laminated panel.

Thus, starting from a cork panel (4) which, in the preferred embodiment, is manufactured to a thickness of about 80 mm, it is coated with at least two blades (1,1 ') each consisting of a thermosetting resinous matrix of epoxide impregnated in one or more layers of fiberglass. The result is a composite sandwich panel composed of at least 3 layers, all of which contribute to the mechanical strength of the panel, and wherein the panel is structurally tough and self-supporting. Thus, contrary to the examples cited, cork agglomerate not only performs insulating but also structural functions.

In order to remedy the problem of corkboard panels being commercially available in sections (3, 3 ') only of dimensions often smaller than those required to construct the intended panels (4), various types of end-to-end connection of said sections have been studied. (3.3 ').

Of the various types of connection tested (Fig. 3), the overlapping connection of the panels by the juxtaposition of notches of the two sections (Fig. 3c) gave the best results, but many others are possible as illustrated in fig. 3

With this type of connection, from commercially sized cork sections (3, 3 '), panels (4) of virtually any size are obtained.

After connecting the sections (3, 3 ') necessary to create a panel (4) of the desired size, they are covered. on both sides with blades (2). The blades (2) consist of glass fiber impregnated with thermosetting epoxide resin and, after bonding with the panel (4) by means of an adhesive (5), a new composite material with a mechanical behavior far superior to the existing one is obtained. with each of the materials separately. The fiberglass matrix is responsible for the agglutination and transmission of the charges to the fibers. These blades have low weight and high strength. Its modulus of elasticity, resistance to moisture and alkaline environments are also reduced. In their preferred embodiment, the glass fibers used are placed in woven blankets and are arranged at random. Alternatively the glass fibers may be placed in a directed or interlaced matrix.

The cork agglomerate core has the functions of guaranteeing the thermal, acoustic and damping capacity. The low density of this material reduces the consumption of raw materials per square meter of panel produced. On the other hand, the use of this raw material in the core also allows a good specific stiffness, ie a good compromise between the weight and the stiffness of the panel.

Lastly, it should also be noted that in order to be able to produce corkboard core fibrous panels it is necessary to adopt special techniques during the manufacturing process, especially as regards the bonding between the layers, ie between the corkboard and the corkboard. blades, as we are working with a cluster of irregular faces, with plenty of voids and easily disintegrated, which can compromise the adhesion between the three layers. It should also be noted that the cork agglomerate core fibreboard obtained by the above described process does not require the use of any additional reinforcement or structure for obtain the structural strength required to be used as a wall or ceiling in the construction industry.

Brief Description of the Drawings

To complement the description and to help understand the features of the invention, we present a set of figures, as well as the description and presentation of results of the mechanical tests performed.

Figure 1 represents a preferred embodiment of the cork core laminated panel

Figure 2 is a photograph of a section of the cork core laminated panel

Figure 3 represents some examples of cross-section links.

Mechanical tests

To characterize the behavior of the preferred execution of cork core laminated panel, a testing campaign was carried out.

The fiberglass used in the tests below has a density of 750g / m2 and a geometry of +/- 45 °. The epoxy resin used has a density of 1.0g / l hardened by a catalyst of density between 0.95-1.08g / l. According to the resin supplier the epoxy resin impregnated fiberglass matrix withstands tensile stresses between 55-65 MPa and has a modulus of elasticity between 1.5-2 GPa, these assumptions were validated in the campaign. The cork agglomerate used has a thickness of 80mm, a density between 105-125 kg / m ³ , a thermal conductivity of 0.040 W / m K and a thermal resistance of 1.00 m ² K / W.

Mechanical Properties of Epoxy Resin Impregnated Fiberglass Blades

The experimental testing campaign led to the conclusion that the WHS epoxy-reinforced fiberglass has a tensile strength of 69.5 MPa (695 N / m2), which is higher than the tensile strength of the epoxy resin manufacturer (55 -65 MPa). Mechanical Properties of WHS Sandwich Panel with Cork Agglomerate Core

Interpretation of Results

 As can be seen in the table above, the deformability of the panel in the normal direction to its plane is conditioned by the deformability of the cork core, since the variability of the values obtained with and without blade is very small, however if we analyze the deformability of the panel with and without blades in the direction of their plane, the difference is from 0.0042GPa without blade to 6.49GPa with blade, ie the blades play a relevant role in the deformability of the panel.

In its preferred embodiment, the cork agglomerate used has a thickness of 80mm, a density between 105-125 kg / m ³ , ie for 80mm of panel thickness the specific weight varies from 8.4-10 kg / m2, and The incorporation of the epoxide thermosetting resin-impregnated fiberglass sheets adds to the panel more 1.5kg / m2 on each of the sheets. Thus, by adding little specific weight (about 30%) to the cork board it was possible to greatly increase (over 1,500 times) the mechanical characteristics of it.

Lisbon, 21st August 2015

Claims

Claims 1. Self-supporting fibrous panel consisting of two outer laminae consisting of a combination of a thermosetting epoxide resin matrix impregnated with at least one fiberglass mesh and characterized in that the laminae contain an insulating cork core. Self-supporting fibrous panel according to claim 1, wherein the core is comprised of several cork agglomerate sections joined end to end. Self-supporting fibrous panel according to Claim 2, characterized in that the panel has no structural element or reinforcement on the blade surfaces or inside the core. Self-supporting fibrous panel according to claim 3, characterized in that the core of the panel has a density (specific weight) much lower than that of the blades. Self supporting fibrous panel according to claim 4, characterized by: a. the blades consist of a fiberglass matrix in which the fiberglass mesh assembly has a density of 500 g / m ² or more, B. the blades are hardened and bonded to the core by thermosetting epoxide resins, or others such as polyester, vinylester and phenolic resins having a density of 0.8 g / l or greater, c. the insulating core is composed of agglomerated cork with a thickness of at least 80 mm and a density of 100 kg / m ³ or less ^; 6. Use of self-supporting corkboard fiber-reinforced corkboard in the construction industry as a structural and self-supporting panel to replace or construct walls, floors, roofs, or even bridge and viaduct trays. Lisbon, 21st August 2015