CH684832A5 - Composite panels with two outer layers and a core. - Google Patents

Description

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description

The present invention relates to composite panels with two cover layers and a core, the core having a core mixture which contains a mixture of a filler and binder and the use of such composite panels.

Composite panels consisting of two cover sheets and a core, which consists of a mixture of a granular filler and a binder, are known from DE-PS 2 842 858. It has been described that the core material must contain at least 42.5% by weight of Al (OH) 3 and that liquid, organic reaction resin mixtures, i.e. essentially thermosets, must be used.

Composite panels of this type cannot meet all requirements, since their workability is limited due to the brittleness of the binders. In particular, the flexibility of known composite panels, for example when processing them into structural and facade elements, is limited.

The object of the present invention is to propose composite panels which are easy to process and in particular shaped, such as can be bent or kinked, and which correspond to the requirements of classification as incombustible building materials or components.

According to the invention this is achieved with a core mixture containing 50 to 90% by weight of compounds of calcium and / or magnesium from the series of hydroxides and / or carbonates, 5 to 47% by weight of filler and 3 to 15% by weight of binder .

Composite panels according to the present invention have two cover layers made of film, tape or plate material. Such materials can be plastics, e.g. Polyvinyl chloride, poly-olefins, polyamides, polyesters, fiber-reinforced synthetic resins and the like, for example in a thickness of 0.1 to 5 mm. Metallic materials, such as ferrous or non-ferrous metals, in particular the series of iron, steel, zinc, tin, galvanized iron, copper, bronze, non-ferrous metals, aluminum or aluminum alloys are preferred. Aluminum and aluminum alloys are particularly preferred. The thickness of the cover layers is usually between 0.1 and 3 mm, expediently between 0.3 and 2 mm and preferably between 0.5 and 1.25 mm, for aluminum and aluminum alloy cover layers. Both cover layers can be made of the same material and in the same thickness. It is also possible to choose the two cover layers from different materials. The thicknesses of the two cover layers can be the same or different.

For example, one cover layer can be made of metal and the other cover layer can be made of plastic. The plastic in turn can be made fire-resistant by flame retardants. The plastic can also be reinforced e.g. by fibers or e.g. be foamed.

The core can consist of the core mixture or the core can consist of several layers of the same or different core mixtures, the layers optionally through one or more layers of flat materials, such as metal foils, strips or plates, papers, cardboards, plastic foils and / or Plastic plates can be separated from each other.

For example, composites consist of two cover layers and between them a core made of a metal foil, such as an aluminum foil, and on both sides of the foil there is a layer of core mixture.

The cover layers can be connected to one another with the core material, for example by the method according to EP-A 0 423 074. If the core mixture has sufficient adhesive force under the given conditions, the core mixture can be bonded directly to the cover layers. Adhesives or adhesion promoters or other adhesive aids, such as adhesive tapes, can also be provided between the cover layers and the core material for the purpose of permanent connection. This also applies mutatis mutandis to other core structures which are made up of two or more core layers and, if appropriate, flat materials in between.

The composite plates according to the invention contain 50 to 90% by weight, expediently 60 to 80% by weight and preferably 65 to 75% by weight of compounds of calcium and / or magnesium from the series of the hydroxides and / or carbonates in the core mixture.

Examples of such connections are the forms of limestone. The characteristic component of limestone is calcium carbonate. The origin of the limestone is not critical. Natural limestone or chemically produced calcium carbonate can be used. Depending on the origin, the limestone can be limestone, dolomitic limestone, dolomite, merged dolomite, marl limestone, dolomitised marl limestone, marl dolomite, limestone marl, etc.

From the series of magnesium compounds, for example, Mg (OH) 2, Mg (C03), Mg3Ca (C03) 4, huntite, Mg3Ca (C03) 4, hydromagne-sit, Mg4 (C03) 3 (0H) 2 - 3H2O etc. can be mentioned become.

The compounds can also be accompanied by the usual natural and technical impurities. The compounds are expediently used in powder form and preferably in a sieve fraction of 0.1 to 2.0 mm and in particular of 0.3 to 0.75 mm. Such fractions are e.g. available for limestone from natural quarries by crushing, grinding, sieving, washing and drying.

The incombustibility of the composite panels of the present invention, even in the presence of organic substances, such as plastics and mixtures, is achieved by incorporating the large amounts of calcium and / or magnesium compounds. In particular, in the case of a fire, endothermic non-flammable, non-toxic gases are released in the case of a fire.

The mode of operation is based on a reduction in the calorific value per kg of mixture in accordance with the degree of filling, and on the other hand

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on that, for example, for the decomposition of CaCC> 3 according to the formula

CaCC> 3 -> CaO + CO2 at temperatures above 800 ° C

Energy is consumed. In addition, the CO2 acts as an oxygen displacing gas.

The core mixture of the composite panels also contains at least one, preferably one, filler. The fillers can preferably be used in amounts of 20 to 30% by weight and particularly preferably 20 to 25% by weight. Such fillers can be kaolins, artificial aluminum silicates and oxide hydrates, titanium dioxide, talc, gypsum, barium sulfate, barite, calcium silicate, diatomaceous earth, zinc oxide, alone or mixtures thereof.

Preferred fillers are light fillers, for example lava slag, pumice, aggregates of clay, slate, fly ash, waste, which e.g. can be processed wet into granules and expanded by evaporation of the water, expanded clay, hollow corundum, hard coal slag, brick chippings, vermiculite, perlite, expanded mica, expanded perlite, diatomaceous earth, foam sand, foam gravel etc. Glass hollow spheres and foam glass are particularly preferred as light fillers. Hollow glass spheres and foam glass can be produced, for example, from silicate glasses containing boron oxide, aluminum oxide, sodium oxide or lead oxide. The density of hollow glass spheres can be, for example, from 0.4 to 0.9 g / cm 3 (bulk density).

Particularly preferred light fillers are hollow spheres made of aluminum silicate in a size of 5 to 500 µm and an average diameter of 60 to 200 µm.

The light fillers are expediently used in amounts of 10 to 25% by weight in the core mixture.

The core mixture in composites according to the present invention contains 3 to 15% by weight of a binder. Such binders can be, for example, inorganic binders, such as phosphates, phosphoric acid, aluminum orthophosphates, kaolin, ben-tonite, chromium oxide (Cr2C> 3), magnesium orthoborate, aluminum hydroxychloride, alkali metal silicates, such as sodium silicates, very finely divided (micronized) aluminum hydroxide, cements, Portland cements, calcium aluminates, Clays and mixtures of such binders and / or organic binders.

Core mixtures containing 5 to 15% by weight of organic binder are preferred. Examples of organic binders that can be used are polymer mixtures, homopolymers or copolymers and expediently thermoplastic plastics, in particular the series of polyolefins.

Examples of thermoplastics from the series of polyolefins are polyolefins such as polyethylene, e.g. High density polyethylene (HDPE, density greater than 0.944g / cm3), medium density polyethylene (MDPE, density 0.926-0.940 g / cm3), linear medium density polyethylene (LMDPE, density 0.926-0.940 g / cm3), low density polyethylene ( LDPE, density 0.910-0.925 g / cm3) and linear low density polyethylene (LLDPE, density 0.916-

0.925 g / cm3), polypropylene, atactic, isotactic, amorphous and crystalline polypropylene, as well as any mixtures thereof, poly-1-butene, poly-3-methylbutene, poly-4-methylpentene and copolymers thereof, e.g. of polyethylene with vinyl acetate, vinyl acetate and acrylic esters, vinyl alcohol, acrylic acid, e.g. ionomer resins, such as copolymers of ethylene with about 11% acrylic acid, methacrylic acid, maleic acid, acrylic esters, maleic esters, methacrylic esters, tetrafluoroethylene or polypropylene, and also random copolymers, block copolymers or olefin polymer-elastomer mixtures. Polyethylenes, polyethylene copolymers and polypropylene are preferred.

Appropriate core mixtures contain 5 to 15% by weight of a polyethylene-containing binder.

Thermoplastic plastics in powder or granulate form with a grain size of 5 to 150 μm are particularly useful as binders. Of the thermoplastics in this grain size, the polyethylene copolymers with heteropolymers, such as Ethylene, graft polymers with 5 to 25% acrylic acid or acrylic acid ester and maleic acid or maleic acid ester are particularly preferred.

Of particular importance are composite panels according to the present invention, the core mixture of which is 60 to 80% by weight, preferably 65 to 75% by weight of limestone, 20 to 30% by weight, preferably 20 to 25% by weight of fillers or 10 to 25% by weight .-% light fillers, and 5 to 15 wt .-%, contains thermoplastic binders.

The core mixtures can also contain other auxiliaries. Core mixtures containing flame retardants, smoke reducers and / or processing aids, such as dispersants, are preferred.

As flame retardants, for example, inorganic additives such as antimony trioxide, optionally together with halogen-containing organic additives, aluminum oxide hydrate, ammonium orthophosphate or polyphosphate or ammonium sulfonate or halogenated organic compounds, such as brominated aromatics, optionally in combination with antimony trioxide, chlorinated paraffins, addition products of hexachlorocylopentadiene, tetrabrombisphen A, tetrabromophthalic anhydride, red phosphorus, organic phosphorus compounds such as phosphates, phosphites and phosphonates or halogenated organic phosphorus compounds, diphosphonate phosphate, quaternary phosphonium halides such as the ethylidene bis [tri- (2-cyanoethyl) phosphonium] bromide and its 1: 1 mixture with hexabromobenzene.

Zinc (B02) 2 • 2H2O or 2ZnO • (6203) 3 ■ (H2Û) 3 • 5 or active substances from the series of metallocenes, in particular Ferracenes, or from the series of metal acetylacetonates can be mentioned as examples of smoke reducers.

The flame retardants and smoke reducers resp. Smoke suppressors can be used in amounts of e.g. 0.1 to 2% by weight, based on the core mixture, can be used.

The core material may also contain a dispersant, preferably alumina, especially

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in fine powder form with a particle size of 4-50 nm (nanometers). At most, porous, finely divided, high-purity silicon oxide and in particular silicon dioxide obtained from an evaporation process can also be used as the dispersant. The amount of dispersant can e.g. 0.01 to 1 wt .-%, based on the core mixture.

The flame retardant, the smoke reducer and / or the smoke suppressant can be processed in a production process according to the invention with the dispersant by grinding and mixing or by mixing to form a premix and the premix can be combined with the compounds of calcium and / or magnesium and the fillers processed into the core mix.

The core mix can be made by mixing the various ingredients, e.g. dry mixing in a solid mixer, such as a compulsory mixer, screw mixer, tumble mixer or fluid mixer or other continuous or discontinuous mixers.

The further processing of the core mixture to form composite panels can be carried out, for example, using a method as described in EP-A 0 087 546 or EP-A 0 0423 074.

The composite panels according to the present invention can, for example, according to the above-mentioned methods in particular by using pressures from 1 to 50 bar (1 • 105 to 50 ■ 105 Pa), expediently from 5 to 25 bar (5 • 105 to 25 • 105 Pa) and at the same time temperatures of 120 to 250 ° C, expediently up to 220 ° C, especially when using a belt press. The cover layers are bonded to the core layer, optionally with adhesive aids such as adhesive films, and the core mixture solidifies when exposed to pressure and heat. The composite panels that can be produced in this way can be processed as required, e.g. cut to the desired size, e.g. by sawing, milling or cutting or by e.g. Drilling or cutting can be provided with recesses. It is also possible to deform the composite panels, for example to bend or bend them. It is helpful if one of the cover layers, in particular on the inside of the bending radius, is provided with one or more notches or cuts. The notches or cuts can continue into the core.

When bending, the core bonded with thermoplastic materials can absorb the bending movement and the outside of the composite panel, supported by the core or core remnant, experiences a clean bending line.

The composite panels according to the invention can be used as building materials, facade panels, cladding of buildings, partitions in buildings, in vehicle and shipbuilding and in apparatus and machine construction.

Preferred is the use as bendable building materials, such as facade panels, cladding of buildings, or partitions in buildings, in vehicle and shipbuilding and in apparatus and machine construction.

All percentages or parts are by weight unless otherwise stated.

Claims (9)

Claims 1. Composite panels with two cover layers and a core, the core having a core mixture which contains a mixture of a filler and a binder, characterized in that the core mixture 50 to 90 wt .-% of compounds of calcium and / or magnesium of the series which contains hydroxides and / or carbonates, 5 to 47% by weight of filler and 3 to 15% by weight of binder. 2. Composite panels according to claim 1, characterized in that the core mixture contains 5 to 47 wt .-% light filler as a filler. 3. Composite panels according to claim 1, characterized in that the core mixture contains 5 to 15 wt .-% organic binder as a binder. 4. Composite panels according to claim 1, characterized in that the core mixture contains 5 to 15 wt .-% thermoplastic binder as a binder. 5. Composite panels according to claim 1, characterized in that the core mixture contains 5 to 15 wt .-% polyethylene-containing binder as a binder. 6. Composite panels according to claim 1, characterized in that the core mixture 60 to 75 wt .-% limestone, 20 to 30 wt .-% filler or 10 to 25 wt .-% light filler, and 5 to 15 wt .-% thermoplastic binder contains. 7. Composite panels according to claim 1, characterized in that the core mixture contains 60 to 80 wt .-% limestone, 10 to 25 wt .-% light filler, and 5 to 15 wt .-% thermoplastic binder. 8. Composite panels according to claim 1, characterized in that the core mixture contains flame retardants, smoke reducers and / or dispersing aids. 9. The method for producing composite panels according to claim 1 with two cover layers and a core, wherein the core has a core mixture which contains a mixture of a filler and binder, characterized in that the flame retardant, the smoke reducer and / or the smoke suppressant the dispersant is processed by grinding and mixing or by mixing to form a premix and the premix is processed with the compounds of calcium and / or magnesium and the fillers to form the core mixture. 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 4th