FI72570C - FOERFARANDE FOER FRAMSTAELLNING AV EN ISOLERAD BETONGPRODUKT. - Google Patents

Description

72570

Method for making an insulated concrete product

The invention relates to a method for producing a concrete product, in particular an insulated concrete element, according to the preamble of claim 1. According to this method, the concrete mass is first cast in a suitable mold, after which a first bonding layer is applied to the surface of the mass and a second layer of insulating material is applied to said layer by spraying a foamable material between the concrete element and above it.

Concrete has two properties that make it a permanent and ever-evolving building material. These properties are, on the one hand, its easy handling, which allows it to be molded into the desired shapes, and, on the other hand, its reasonable weather resistance. Today, moreover, the ability of concrete mass to store heat within structures is emerging as an important new property.

The manufacture of building components is becoming more and more in line with the production methods of the process industry. This means moving to continuous flow production, and combining all production stages as far as possible.

In addition, the aim is to combine the different construction materials in production in order to achieve an integral product in the shortest possible time. After all, in modern continuous production, it is not desirable, for example, to wait for the concrete to harden, for the surface to dry, etc., before the next layer, coating or combination is applied as part of the structure.

Thermal insulation is one of the integrated parts of such a structure, and as such one of the most important combinations of a concrete structure. The function of the thermal insulators is to prevent the flow of air inside the insulating part of the element, and thus to reduce thermal convection through the 2 72570 structural element. The insulators used are usually either fibrous (mineral wools) or cellular (foamed plastics). For each insulation material, an optimum value for the density of the material can be found in terms of its thermal insulation capacity. This optimum density is about 40 kg / m3 for polymeric insulation foams, while mineral wool insulation is usually brought to the installation site as a material with a density of 40-80 kg / m3.

The preferred thermal insulation is one which is foamed at the installation site, adheres to its substrate when foamed and which, in the case of a concrete structure, can be foamed and attached to fresh concrete. The most commonly used thermal insulation, glass or rock wool made of mineral fibers, is ill-suited for the industrial production of structural elements, because the manufacture of an integral product from it requires a lot of manual work.

It is always important, no matter how the thermal insulation is installed, that its thickness is the desired thickness and that it remains constant. The latter is particularly important for the next coating and the appearance of the element. In addition to this, it is important that the thermal insulation is made to adhere reasonably well to its substrate, and in particular to a substrate which is fresh concrete.

It is already known from the patent literature to improve the connection between an element and an insulating layer of foam by means of adhesive mortars and substances. Thus, according to GB 1 528 248, a building board consisting of gypsum and insulating material can be produced by first applying an epoxy, polychloroprene, vinyl, acrylic, resorcinol-formaldehyde or polyurethane-based adhesive to the surface of the hot gypsum boards coming from the furnace, formaldehyde foam insulator.

FI patent application 1132/66, on the other hand, describes the production of a building board as a continuous process by pouring 3,72570 foam material between two cover layer webs, whereby the thickness of the insulation layer is limited from above by means of a conveyor belt.

The object of the present invention is to provide a completely new method for the production of concrete products, which method is particularly suitable for modern flux production.

In the method, the foam is sprayed in accordance with FI patent application 1132/66 into a closed space, which is delimited at the top by a movable track, whereby the foam is spread evenly on the concrete surface. The track preferably moves in the upward direction of the foam, i.e. in the same direction as the spraying progresses.

The invention is based on the idea that a one-component polyurethane plastic is used as the material forming the bonding layer, and a two-component polyurethane is used as the foamable insulating material. The one-component polyurethane plastic is adapted to cover the surface of the fresh concrete element so as to form an adhesive layer of foamed bicomponent polyurethane on the one hand and to prevent migration of water from the concrete layer to the insulation layer during the foaming step.

More specifically, the solution according to the invention is mainly characterized by what is set forth in the characterizing part of claim 1.

The invention provides considerable advantages. Thus, it has solved the problems related to the mutual adhesion of the element and the insulator, to the uniform layer thickness of the insulator and to the achievement of a controlled density in a cheap and simple manner.

In the following exemplary embodiment, the invention will be examined in more detail with the aid of the accompanying drawing, which in principle shows the performance of the method according to the invention in a side view.

4,72570

The concrete body 1 to be produced is cast in a manner known per se into the desired shape. The concrete mass used is a mass with a water / binder ratio such that no water separation occurs. After this, the so-called one-component polyurethane (1-comp. PU), which forms a thin layer 2 on top of the concrete. As the polyurethane, for example, a product which is now commonly used as a jointing and similar foam mass can be used. It is preferably formulated to react with water. This thin sprayed layer 2 adheres to the fresh concrete surface in places and forms a uniform layer. Two-component polyurethane (2-comp. PU) 3, catalyzed without water and typically with a fluorinated hydrocarbon as a blowing agent, is immediately foamed on top of the above-mentioned adhesive layer 2. Of course, another substance known per se, such as a brominated or chlorinated hydrocarbon or a nitrogen-releasing compound (dinitrosopentamethylenetetramine), can also be used as the blowing agent. Two-component polyurethane is known to react violently with water. If it were foamed directly onto fresh concrete, water would release carbon dioxide and large blisters would form in the material. The insulation would therefore not adhere well to its substrate. The adhesive layer formed by the one-component polyurethane thus also seeks to prevent the migration of water from the concrete layer into the insulating polyurethane during the flotation step.

Arranged above the cast concrete layer 1 is a rotating roller mat 6 resting on rollers 4, 5, the width of which is approximately equal to the width of the insulating layer 3 to be produced on top of the concrete layer. Usually, it is thus approximately as wide as the concrete piece itself. The rollers 4, 5 are parallel to each other, and preferably transverse to the concrete body. Track distance from the underside 6 of the concrete surface substantially corresponds to the desired thickness of the insulating layer, and the mat is in a horizontal plane at least approximately parallel to the surface of the concrete. The 2-component PU sprayer 5 72570 is limited to the enclosed space by the concrete body and the track as shown in the figure (if desired, the space can still be limited by side edges detached from the sides). The polyurethane spray nozzle is then arranged under the track 6, past the front roller 4. As can be seen from the figure, the spraying is carried out horizontally, preferably from the direction of the concrete product to be coated. The track 6 moves relative to the concrete body in the rising direction of the foam, i.e. in the direction of spraying (to the right in the figure). The track mat limits the layer thickness of the insulation 3, and since it is horizontally parallel to the concrete surface, an even thickness of the insulation layer is obtained. At the same time, the optimum value of the density for the thermal insulation capacity of the material is reached by means of the roller mat 6.

The track 6 used is a flexible and strong preparation. The materials used are mainly fabric-reinforced natural or synthetic elastomeric mats (rubber mats) and corresponding polymer products. If desired, the mat can be coated with a plastic film, such as PVC, PE or PP film, to effectively prevent the polyurethane to be foamed from adhering to its surface.

The length of the track 4 is selected on the one hand according to its rotational speed and on the other hand according to the composition of the polyurethane mixture to be foamed. One skilled in the art will be able to easily select a suitable track length based on the flotation rate of the mixture.

In addition to the above, a final coating can be attached to the fabrication, which is performed like the previous two sprays. Thus, polyurethanes provide highly durable elastomeric coatings that can also be sprayed and preferably directly onto freshly sprayed, elevated foam. This provides a surface that can withstand even walking, even if the substrate is very light foam. The elastomeric coating distributes the load well without breaking, and returns to its original shape when the point load is removed.

6 72570

A dense polyurethane elastomer layer 7 is thus applied on top of the formed flat foam layer to produce a final weather-resistant and step-resistant coating.

It is particularly advantageous that all the separate polymer layers are sprayed rapidly in succession, with the best adhesion and adhesion between the layers.

In continuous production, the movement of the polymer spray nozzles and track relative to the concrete body is accomplished either by fitting them to a movable operating carriage that is moved along the concrete body during the process, or by mounting them fixed and moving the concrete body forward past them.

Claims (4)

7 72570 A method for producing a concrete product, in particular an insulated concrete element, which comprises - first pouring a concrete mass into a suitable mold, - applying a first bonding layer (2) to a fresh, moist concrete surface, - applying a second foamed insulating material to the formed layer (2). layer (3) by spraying a foamable substance horizontally between the concrete element (1) and above it, at a distance between its surface and the roll (6), preferably from the direction of the concrete product to be coated, characterized in that - a one-component polyurethane plastic is used as the bonding layer (2), a two-component polyurethane is used as the foamable insulating material, the one-component polyurethane plastic being adapted to cover the surface of the fresh concrete element (1) so as to form an adhesive layer (2) of the foamed two-component polyurethane and prevent concrete migration of water from the layer (1) to the insulating layer (3) during the flotation step. Method according to Claim 1, characterized in that the spray nozzle for the insulating material to be foamed is arranged under the track (6), past this front roller (4). Method according to one of the preceding claims, characterized in that the insulating foam layer (3) is coated with a dense polyurethane elastomer layer (7) in order to produce a final weatherproof and step-resistant coating. A method according to claim 3, characterized in that all the separate polymer layers (2, 3 e 72570 and 7) are sprayed rapidly in succession, thus providing the best adhesion between the different layers.