NO125857B - - Google Patents

Description

Method of manufacture of

disc or plate-shaped building elements.

The present invention relates to a method for production

of non-combustible, water- and frost-resistant boards or discs for building purposes. The purpose is primarily to procure building boards, which essentially can be used for the same purpose as is currently used, e.g. fibreboard, chipboard, plasterboard and the like. Furthermore, however, it is an object of the invention to provide a disc or plate-shaped building element, which can be manufactured in substantially stronger dimensions, so that it can be used as a wall element for both internal and external walls. Neither the known wood fiber and wood wool boards nor the known gypsum boards" are water or frost resistant.

and the chipboards are also flammable, while the plasterboards have a relatively poor buoyancy resistance.

The purpose of the invention is thus to provide a simple and inexpensive method for the production of a non-combustible as well as water- and frost-resistant building board, which also has a high bending strength and yet a relatively low weight.

IN

What primarily characterizes the method according to the invention for the production of a disc or plate-shaped building element consists in

a) that a relatively thin, largely uniformly shaped layer of loose, randomly oriented glass fibers is laid out on a mold base, b) that the fibers in this fiber layer are bonded to each other by applying a binder, c) that a mass consisting of a water foam containing cement or gypsum as well as fiber material in a dispersed state, d) that a layer of loose, randomly oriented glass fibers treated is placed and pressed down on the upper side of the stopped mass

in a similar way as in steps a) and b), and

e) that the element thus formed is dried and hardened thereafter

to be removed from the form base.

in

In a particularly advantageous embodiment of this method, a layer of synthetic plastic, e.g. polyethylene, carbamide, melamine, epoxy or polyester.

A solution or emulsion of synthetic plastic is advantageously used as a binder for the fiber layers on both sides of the central core of foam concrete or foam plaster.

It is particularly advantageous if the water foam used for the production of the element's central core, which contains cement or gypsum as well as fiber material, is produced from a water emulsion of one or more synthetic, water-insoluble polymers, such as e.g. polyvinyl chloride, polyvinyl acetate, polyvinylidene chloride, acrylate, epoxy, polyester, styrene-butadiene or copolymers thereof, as thereby a central core is obtained in the building element consisting of fiber-reinforced foam concrete or foam plaster and also containing polymer material that improves the bond between the fiber material and the concrete, respectively the plaster.

A plate produced in accordance with the invention has a core of fibre-reinforced foam concrete or foam plaster, which is preferably further reinforced by the fact that the foam concrete or foam plaster contains a synthetic water-insoluble polymer material. This core takes up most of the plate's thickness and gives the plate the desired stability and compressive strength. As a result of the porous nature of this core, the board has a relatively low weight and, in addition, relatively good heat and sound insulating properties. As a result of the binder-bound fiber layers which are arranged on both sides of the porous core and which are firmly connected to this, the desired high bending strength is achieved in the plate. These layers also serve to seal the inner porous core against water and moisture, whereby the plate becomes water and moisture resistant. These properties of the plate are further improved by the fact that, according to a further feature of the invention, an outermost layer is applied to the plate on each side and consisting of synthetic plastic such as e.g. polyethylene, carbamide, melamine, epoxy or polyester. These outermost layers give the board a weather-resistant and maintenance-free exterior.

Moreover, these outermost layers result in a further improvement

sealing the inside of the board against moisture and water, so that the board becomes water and frost resistant. The plate also gets, with the outermost layers, an aesthetic appearance and can also be given a desired color without difficulty by pigmenting these outermost plastic layers in a manner known per se. Mineral grains can also be mixed into the plastic layers to achieve aesthetic effects. When using such outermost plastic layers on both sides of the plate, the production is advantageously carried out in such a way that the fibers in the binder-bound fiber layers on both sides of the central core of foam concrete or gypsum also extend somewhat into the outer plastic layers .

In the choice of materials used for the various parts of the building

in

the element becomes this non-combustible.

The method according to the invention can with advantage

realized in the following exemplary way:

1. A layer of arbitrarily oriented, loose fibers is placed on a suitable mold base, e.g. asbestos, mineral wool or fiberglass. The thickness of the fiber layer can e.g. equivalent to 100 to 200 g/m p. 2. A binder is applied to the fiber layer, e.g. in the form of a cement or plaster mass added to a water emulsion of a synthetic water-insoluble polymer, such as, for example, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride. It can e.g. a cement mass is used which consists of 7% by weight of cement, 2% by weight of water and 2% by weight of polyvinyl acetate emulsion (approx. 50% dry matter). As a binder for the fiber layer, a cement or plaster slurry can (alternatively) be used without the addition of polymer material or just a liquid synthetic plastic material. Appropriately, the mold base is vibrated so that the binder penetrates into and impregnates the fiber layer. 3. A mass is placed on the thus obtained fiber-reinforced binder layer of foam concrete or foam plaster containing fiber material and synthetic woolable polymer material. This foam concrete mass or foam plaster mass can advantageously be produced by mixing a water emulsion of a synthetic, water-insoluble polymer, for example polyvinyl chloride, polyvinyl acetate, polyvinylidene chloride, acrylate, epoxy, polyester or styrene-butadiene, with about 1 r 10, preferably 2-6 percent by weight of polymer and about 1 percent by weight of a substance that lowers the surface tension, e.g. sodium alkyl suifonate, and possibly a foam stabilizing substance, e.g. carboxymethyl cellulose, are stirred vigorously or whisked until a stable water-polymer foam is obtained In this foam or un where the projection of this is dispersed approx. 2-20% by weight mineral fibres, e.g. mineral wool or asbestos. During conversion, cement1 or gypsum is finally added until a desired water/cement ratio or water/gypsum ratio is achieved. This ratio should preferably be approx. 0.5 to 0.6 or possibly

higher, depending on the Snsket density.

h. On the layer of foam concrete or foam plaster, a thin layer of mineral fibers or glass fibers that have already been treated with a binder as mentioned under point 2 above is laid down, possibly rolled down. 5. The thus produced plate or disk-shaped element is then cured, preferably at a temperature of 50 - 70°C. 6. After the hydraulic binder in the element has hardened and the excess water has evaporated, both sides of the element are coated or impregnated with a plastic that may be pigmented or mixed with mineral grains. This can happen by the plastic in the form of a solution being ironed or sprayed on both sides of the element. For this purpose, e.g. Carbide-clear varnish with aluminum chrome orthophosphate as hardener, epoxy varnish, or a mixture of polyester (70%) and styrene (30%) with hardener, are used. The plastic material can also, especially if melamine is used, be applied

on the sides of the element in a solid state in the form of a fine-grained powder which is caused to melt and form a plastic layer by the element passing between hot rollers.

In the case of a building board produced in accordance with the invention and intended for use for the same purpose as conventional wood fiber boards, plasterboard etc. the central core of fibre-reinforced foam concrete or foam plaster, optionally reinforced with polymer material, can have a thickness of 5 - 20 mm. For thicker building elements designed to be used as wall elements, the core can have a thickness of e.g. 50 - 200 mm. On both sides of the central core of foam concrete or foam plaster are the binder-bound fiber layers which can have a thickness of e.g.

1 - 10 mm depending on the overall thickness of the building element. The outermost plastic layers on both sides of the building element can

have a thickness of e.g. 0.1 - 3 mm.

Claims (7)

1. Method for the production of a disc- or plate-shaped building element, characterized by) that a relatively thin, mostly uniformly shaped layer of loose, [randomly oriented glass fibers] is laid out on a form base, b) that the fibers in this fiber layer are bonded to each other by application of a binding agent, c) that a mass consisting of a water foam containing cement or gypsum as well as fiber material in a dispersed state is placed on the bound fiber layer, d) that a layer of loess is placed and pressed down on the upper side of the stopped mass, randomly oriented glass fibers treated in a similar way as in steps a) and b), and e) that the resulting element is used and hardened and then in removed from the form base. in 2. Procedure as stated in, claim 1, characterized in that the two surfaces of the element, after this has been dried, hardened and removed from the mold base, are coated with a layer of synthetic plastic, e.g. polyethylene, carbamide, melamine, epoxy or polyester 3. Procedure as stated in 'claim 2, characterized in that the plastic layer is produced by coating or spraying the two element surfaces in with plastic solution. k. Procedure as stated in claim 2, characterized in that the plastic layer is produced by the plastic material being applied to the element surfaces in solid form and then melted. 5. Method as stated in claim 1 - characterized in that a solution or emulsion of synthetic plastic is used as a binder in steps b) and d). 6. Procedure as stated in claims 1-5? characterized in that the foam in step c) is produced from a water emulsion of one or more synthetic, water-insoluble polymers, such as e.g. polyvinyl chloride, polyvinyl acetate, polyvinylidene chloride, acrylate, epoxy, polyester, styrene-butadiene or copolymers thereof. 7. Method as stated in claim 6, characterized in that for the production of the mass in step c) a water-polymer emulsion containing 1-10, preferably 2-6 weight percent polymer and approx. 1 weight percent surface tension lowering agent, where the emulsion is transferred by whisking or stirring to a foam in which it is dispersed 2-20% by weight inorganic fiber material, after which cement or gypsum is added, preferably to a water-cement or water-gypsum ratio of approx. 0.5 - 0.6.