CZ298553B6 - Sandwich plate based on stone and process for producing thereof - Google Patents

Abstract

In the present invention, there is disclosed an artificial or natural stone based sandwich plate consisting of a face layer (1) of stone being selected from the group consisting of artificial or natural stone being 5 to 20 mm thick and a bottom layer (2) of hardened foam of polyurethane material being 5 to 100 mm thick, having density within the range of 45 to 500 kg/me3, which layers (1, 2) are adhesively bonded to each another. The polyol component, from which the polyurethane material is produced, contains at least 20 percent by weight of polyol manufactured on the base of vegetable oils. Preferably, a netting (3) of mineral or organic fibers is incorporated in a depth of 0.2 to 10 mm below upper surface of the sandwich plate bottom layer (2) of the polyurethane material hardened foam. The netting (3) is formed by a cloth or a knitwear, preferably warp knitwear of synthetic fibers or a reinforcing grate of mineral fiber cloth. There is also disclosed a process for producing the above-described sandwich plate, said process being characterized in that the bottom layer of polyurethane material hardened foam is formed by injection thereof into a mold, preferably with a netting (3) stretched therein. Foamed polyurethane material hardens in the mol the dimensions of which correspond to the hardened polyurethane material hardened foam bottom layer. The hardened polyurethane material is then adhesively bonded to the back of the stone (1) face, after being removed from the mold.

Description

Sandwich board based on stone and method of its production

Technical field

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial or natural stone sandwich board and to a process for the manufacture thereof.

BACKGROUND OF THE INVENTION

The interior architecture of the buildings uses large-area construction elements made of artificial or natural stone, such as worktops of kitchen tables, bathroom and laboratory furniture, conference tables, tiles, floor tiles, aesthetic accessories.

Slabs based on artificial or natural stone have the disadvantage of their high bulk density. The products are heavy, difficult to handle both during logical operations and further processing and assembly. Due to their weight, they require a corresponding reinforced support system.

Solid and hard material requires demanding machining and considerable consumption of expensive, mostly diamond tools.

US 2004/0115415 A1 discloses a method of making a sandwich panel in which a cured polyurethane foam layer is formed in the mold and an artificial or natural stone layer is adhered thereto, or a reinforcing mat or fleece is inserted between the two layers.

According to the US document, the laminated body - sandwich plate is optionally formed in one operation. Thereafter, a reinforcing mat or fleece is placed in a molded layer of adhesive applied to the stone body before the reinforcing composition of polyols, polyisocyanates, fatty acids, amines and other substances to form the polyurethane is introduced.

SUMMARY OF THE INVENTION

The above-mentioned drawbacks associated with the use of high-density artificial or natural stone slabs are solved by a sandwich slab according to the invention which consists of a facing layer of stone selected from the group consisting of artificial or natural stone of 5 to 20 mm thickness. made of polyurethane material with a thickness of 5 to 100 mm and a density of 45 to 500 kg / m ³ , which are glued together.

The polyol component from which the polyurethane composition is made comprises at least 20 wt. polyol produced from vegetable oils. Eco-friendly polyols are made on the basis of vegetable oil, for example rapeseed, sunflower, soybean or palm, which are a renewable raw material source.

In the bottom layer of the cured polyurethane foam there is a mesh of mineral or synthetic fibers, which is embedded in the bottom layer of the cured polyurethane foam with a depth of 0.2 to 10 mm below the outer surface of the bottom layer of the cured polyurethane foam sandwich plate.

The net consists of a textile fabric or knitted fabric, preferably a warp textile knitted fabric, of synthetic fibers selected from the group consisting of polyester or polyacrylonitrile or polyamide synthetic fibers or mixtures thereof. The best is polyester fiber, which is characterized by excellent adhesion to polyurethane.

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The dimensional change (shrinkage) of the knitted fabric or fabric in any direction does not exceed 5%. The net may also consist of a reinforcing grid of a mineral fiber fabric selected from the group of glass, basalt or carbon fibers.

The method for producing a sandwich board is characterized in that the bottom layer of the cured polyurethane foam is formed by mixing the components of a polyurethane system consisting of a polyol component A, which contains at least 20 wt. polyol produced from vegetable oil and from component B based on isocyanate (MDI). The mixture is injected into a mold in which the net is stretched. In the mold corresponding to the bottom layer of the cured polyurethane foam, the foamed polyurethane mass is allowed to cure. After removal from the mold, the cured polyurethane mass is sanded to the required thickness on the side that adheres to the reverse side of the facing stone layer, then coated with adhesive and pressed to the reverse side of the facing stone layer to form a solid stack.

The reinforcing mesh is stretched in a mold such that it is placed in the cured polyurethane foam at a distance of 0.2 to 10 mm below the outer surface of the bottom layer of the cured polyurethane foam of the sandwich plate.

This solution, unlike US 2004/0115415 A1, makes it possible to achieve a completely smooth, glossy compact surface of the polyurethane layer.

The inventors have found that in the process of foaming the polyurethane mass, the foamed composition penetrates through to form the polyurethane mass through the mesh - the fabric reinforcing and the mesh formed does not contain blowing bubbles and forms a highly compact rigid, smooth and glossy layer that protects the cured polyurethane foam influences, mechanical damage, improves aesthetic appearance and facilitates its maintenance.

In this way, the interlaced mesh and the polyurethane layer penetrate the mesh-fabric to significantly strengthen the entire sandwich board stack. The bolt is pulled out of the polyurethane layer of the sandwich plate only when the weight exceeds 70 kg.

The method according to the invention makes it possible to produce flat sandwich plates of a large size of 300 x 130 cm.

The sandwich plate provides the necessary level of mechanical properties, for example, the bearing capacity of the plate at a theoretical span of 560 mm supporting beams is min. 3.4 kN, the load-bearing capacity of the screw connection anchored into the polyurethane mass is min. 0.7 kN. It significantly reduces its weight compared to a solid board, for example, a 35 mm thick sandwich board is 2.8 times lighter than a board of the same dimensions made of artificial stone itself, thus improving maneuverability during production, distribution and further processing, especially in relation to compliance limit of the maximum weight of the load per worker during manual handling. It makes it possible to reduce the demands on the bearing structure of furniture and to reduce the production costs of the sandwich board and the bearing structure. A thinner layer of hard material (stone) is easier to work with less cutting tools.

When used as a cladding material, it contributes significantly to increasing the thermal resistance of the stack of the cladding element, since the thermal conductivity coefficient of the polyurethane layer of the sandwich used, for example, 120 kg / m ^3, is less than 0.032 W / mK.

The polyurethane layer allows easy application of the door joints using dowels used for plasterboard and easy working with conventional woodworking tools.

The manufacturing method used makes it possible to create a smooth and glossy bottom surface of the polyurethane-based sandwich sheet, which is therefore easy to clean, free of any release agents and easily adhered to the carrier body, for example with polyurethane adhesives and sealants.

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The sandwich plate according to the invention imitates a thick-walled plate, but its weight is in multiples lower than the weight of a plate of the same thickness and area made only of artificial stone.

For example, a large slab of artificial stone 300 x 132 x 3 cm (basic format) with a density of 2300 kg / m ³ has a weight of about 273 kg.

For example, a 300 x 132 cm sandwich board with a total thickness of 3 cm consisting of the same type of 10 mm thick artificial stone, a 2.0 cm polyurethane layer and a density of 220 kg / m ³ with a fiberglass fabric weighs approximately 109 kg. 2.5 times lighter than a slab of only 30 mm thick artificial stone.

For example, a 300 x 132 sandwich board with a thickness of 3.5 cm consisting of the same type of 10 mm thick artificial stone, a 25 mm polyurethane layer and a density of 220 kg / m ³ with a knitted fabric of textile fibers weighs about 113 kg and is about 2.8 times lighter than a slab of just 3.5 cm thick artificial stone.

The layer of sandwich plate made of artificial stone can be replaced by natural stone.

Overview of the figure in the drawing

Giant. 1 shows a cross-section of a sandwich plate.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Fig. 1 shows a sandwich plate whose face layer 1 is made of polished artificial stone of size 300x130x1 cm, density 2300 kg / m ³ . The bottom layer 2 of the cured polyurethane foam has a thickness of 25 mm and is located approximately 1 mm below the surface of a mesh (3) made of polyester knitted textile fabric. Both layers are joined by adhesive 4.

A mesh 3 was placed in a mold dimensionally identical to the dimensions required in the lower layer 2 of the cured polyurethane foam. A mixture of a polyurethane system containing 25% by weight of a polyol component was injected into the mold. oil based polyol. Thus, a cured polyurethane foam board having a density of about 220 kg / m ³ and a thickness of a polyurethane layer of 25 to 26 mm was produced, which had a mesh 3 formed of textile polyester knitted fabric positioned about 11 mm below the surface. with the longitudinal axis of the bottom layer 2 of the cured polyurethane foam. On a surface sander, the board was ground on a surface further away from the inserted fabric to a thickness of 25 mm and glued in the press with glue 4 to the facing layer 1 of artificial stone so that the artificial stone forms the facing side of the sandwich board. sandwich boards. A 35 mm thick sandwich plate was created, where the front and back sides are glossy and smooth, allowing easy maintenance (no dirt sticking, washable, easy to clean). A dowel used for screw connections of gypsum plasterboard with a screw was drilled into the board to test the strength of the gate connection. The weight of this board is about 113 kg. The basis weight is 32.3 kg / m ² . The thermal conductivity of the sandwich plate is better than 0.038 W / mK. Bearing capacity without any signs of destruction at span of support beams 560 mm min. 3.4 kN, bearing capacity up to the moment of plate destruction min. 5,5 kN. The strength of the gate joint is min. 0.7 kN.

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Example 2

The facing layer 1 is made of polished artificial stone of size 300x130x1 cm, with a density of 2300 kg / m ³ . The bottom layer 2 of the cured polyurethane foam has a thickness of 21 mm and is located approximately 2 mm below the surface of a mesh (3) formed by a reinforcing mesh made of fiberglass fabric. Both layers are joined by adhesive 4.

In the mold, it was formed from a polyurethane system containing in the polyol component 25 wt. rapeseed oil based polyols The backsheet 2 of cured polyurethane foam with a density of approx. 220 kg / m ³ and a thickness of approx. 21 mm, into which a reinforcing grid made of fiberglass fabric was cast at a depth of 2 mm below the surface. On a surface sander, it was ground on a surface distant from the inserted fabric to a thickness of 20 mm and glued in the press to the artificial stone facing layer 1 so that the polished artificial stone surface forms the face of the sandwich plate and the glossy surface side of sandwich board. The resulting sandwich plate with smooth and glossy surfaces for easy maintenance. The weight of this board is about 108 kg. Surface weight approx. 30,8 kg / m ² . The thermal conductivity of the sandwich plate is better than 0.038 W / mK.

Industrial applicability

The sandwich board according to the invention can be used in stone workshops, kitchen and bathroom studios, in the manufacture of furniture, laying of tiles and moderately loaded tiles and other interior elements using artificial or natural stone. Advantageously, it can be used as a wall or floor tiling to simultaneously increase the thermal resistance of a wall or floor, especially in air-conditioned buildings.

Claims (7)

PATENT CLAIMS Sandwich board based on artificial or natural stone, characterized in that it consists of a facing layer (1) of stone selected from the group consisting of artificial or natural stone with a thickness of 5 to 20 mm and a lower layer (2) of hardened polyurethane foam having a thickness of 5 to 100 mm and a density of 45 to 500 kg / m ³ , which are glued together with an adhesive (4), wherein the polyol component from which the polyurethane composition is made comprises at least 20 wt. of vegetable oils based polyols and in the bottom layer (2) of the cured polyurethane foam there is a mesh (3) of mineral or synthetic fibers at a depth of 0.2 to 10 mm below the outer surface of the bottom layer (2) of cured polyurethane foam sandwich boards. Sandwich board according to claim 1, characterized in that a net (3) consisting of a textile fabric or a knitted fabric of synthetic fibers or mixtures thereof is inserted into the lower layer (2) of the cured polyurethane foam. Sandwich board according to claim 2, characterized in that the net (3) is formed by a warp textile knit. Sandwich board according to claims 2 and 3, characterized in that the synthetic fibers are polyester or polyakiylonitrile or polyamide or a mixture thereof is used. Sandwich board according to claims 2 to 5, characterized in that the dimensional change of the textile fabric and knitted fabric in any direction does not exceed 5%. Sandwich plate according to claim 2, characterized in that a net (3) consisting of a reinforcing grid of mineral fiber fabric selected from the group of glass, basalt or carbon fibers is inserted into the lower layer (2) of the cured polyurethane foam. Method for producing a sandwich board, characterized in that the bottom layer (2) of the cured polyurethane foam is formed from a polyurethane system consisting of a polyol component A, which comprises at least 20 wt. of polyols made on the basis of vegetable oil and from component B on the basis of isocyanate (MDI), their mixture is injected into a mold in which the net is stretched (3), the foamed polyurethane mass is allowed to cure; 5 to 100 mm with a density of 45 to 500 kg / m ³ grind to the required thickness on the side which is glued to the reverse side of the facing layer (1) of stone, then painted with adhesive (4) and pressed with the reverse side of the facing layer (1) ) to form a solid stack.