METHOD FOR THE PREPARATION OF ARTIFICIAL MARBLE PRODUCTS

Abstract: Method for the preparation of an artificial marble product, in which said method an artificial marble mix (1) that contains stone powder and hardening resin is cast into a mould, a wooden core (2) is placed onto the mix and enclosed in mix, whereupon the mix is allowed to harden. By means of the method, it is possible to produce low-weight artificial marble products of favourable raw-material cost, such as table tops.

Description: Method for the preparation of artificial marble products The present invention is concerned with a method for the preparation of artificial marble products of a structure of new type. These products can be used for applications of many sorts in order to replace con¬ ventionally produced products of artificial marble. Artificial marble is a material which is produced by hardening a mixture of stone powder and an appropriate resin. As admixtures are used, e.g., colouring agents, which give the material an ornamental patterning resembling marble. The use of artificial marble has become common in particular in sanitary facilities. Among other objects of use should be mentioned animal fodder troughs, window sills, grave¬ stones, and table tops. A characteristic drawback of artificial marble products is their high weight. When board-like products are produced, it is also possible to glue a thin artificial marble, e.g., onto wooden boards. The product obtained in this way and the method for its production, however, have significant detrimental properties: it is difficult to make the boards remain straight, - by the effect of moisture, the boards split owing to the high tension caused by the surface layer, - glueing is expensive, the artificial marble is fragile and difficult to handle, - fastening of fittings etc. to the board is difficult, - the weight of the product is high. The object of the present invention is to provide a method for the preparation of low-weight artificial marble products of new type, by means of which the drawbacks present in the products produced by glueing onto a board and in the methods for the produc¬ tion of same are avoided. In the method now invented, a wooden core is — enclosed in the mixture of artificial marble in a mould. Advantages of the products in accordance with the present invention are above all low weight and lower material cost. If, for example, one half of the volume of the entire artificial marble product is re¬ placed by particle board, the weight of the product is reduced to about one third, and the raw-material cost is reduced to almost one half. Moreover, the products prepared in accordance with the invention have a stronger and more schock-proof structure, and it is easy to provide them with fittings by means of screws. The method is in particular suitable for the production of board-like products, such as table tops, window sills, as well as of wall and floor boards. The products are intended in particular for moist spaces. In the following, a preferred embodiment of the invention, for the preparation of a table top, will be illustrated in more detail with reference to the attached drawing. The plane-bottom circular mould (diameter 900 mm) used in the method is made of fibreglass or stainless steel. The bottom of the mould faces the top face of the board to be produced, which said top face thereby easily becomes perfectly smooth. Moreover, the mould is provided with fastening means for precise positioning of the board. This guarantees homogeneous structure and remaining of the board straight. Before the mix is cast, the mould is coated with a detaching agent used for the purpose (e.g. TR-wax, high temp.), which makes sure that the board can be detached from the mould. To the detaching agent, it is possible to add agents by means of which a hard surface resistant to chemicals and fire is obtained for the board. A suitable artificial marble mix 1 contains, e.g., 82 % of quartz-limestone sand and 18 % of poly¬ ester resin (e.g. "Norpol 36-00") . The density of such a mix is about 2 kg per litre. The conventional ^ colouring agents etc. admixtures are added to the mix. The wooden core 2 is a circular particle board (diameter 830 mm, thickness 12 mm). In order to promote the evacuation of air, holes 3 are drilled into the board (e.g. 5 mm holes with a spacing of about 100 mm) . On casting, the holes are filled with mix, which also increases the strength of the product upon hardening. Initially, mix is allowed to flow onto the bottom of the mould equalling the thickness of the bottom layer of the board. Thereupon the mould is vibrated so as to evacuate the air, so that possible air bubbles should not cause flaws in the product. Onto the mix placed on the bottom of the mould, the core board is placed, which is covered with a mix layer of required thickness. Hereupon the mould is vibrated again so as to evacuate any air, for any air remaining between the mix and the core board produces a bubble in the surface of the product. Finally, the mix is allowed to harden in the conventional way in the room air or in a heated chamber, whereinafter the product is detached from the mould, inspected, and finished. The mould is cleaned and treated for a new casting operation. The attached drawing also shows a hole 4 made into the centre point of the board.

Claims: WHAT IS CLAIMED IS: - 1. Method for the preparation of an arti¬ ficial marble product, in which said method a mix that contains sand and hardening resin is allowed to flow into a mould and to harden therein, c h a r a c ¬ t e r i z e d in that a wooden core smaller than the mould is placed into the mould and, before hardening, enclosed in the mix of artificial marble. 2. Method as claimed in claim 1 , c h a ¬ a c t e r i z e d in that the mould is vibrated during the casting so as to evacuate any air out of the mould. 3. Method as claimed in claims 1 and 2, c h a r a c t e r i z e d in that mix is allowed to flow onto the bottom of the mould, the mould is vibrated, a wooden core is placed onto the mix, the wooden core is enclosed with the mix, and the mould is vibrated again. _ 4. Product of artificial marble, whose surface consists of a mixture of sand and hardened resin, c h a r a c t e r i z e d in that there is a wooden core inside the product. 5. Product as claimed in claim 4, c h a r ¬ a c t e r i z e d in that in the wooden core, there are holes filled by the mixture. 6. Product as claimed in claim 4 or 5, c h a r a c t e r i z e d in that the wooden core consists of particle board.

Inventors: PEKKINEN PERTTI, PEKKINEN, PERTTI
Applicants: WILH SCHAUMAN AG OY, OY WILH. SCHAUMAN AG
Application year: 1985
Main classification: B32B21
IPC codes: A47B96, B28B23, B29C67, E04F13, E04F15