946/MUM/2003 filed on H. 09. 2003 BACKGROUND OF THE INVENTION The present invention relates to a multi-layered tile or block. More particularly, the present invention relates to a multi-layered tile or block having insulating properties.

Prior art Ceramic tiles and mosaics therefrom are commonly known and used for heat proofing. The disadvantage of this tile is that it being single layered, reduces the temperature only by about 3°-5° C. A two layered cementitious tile is also known and commonly used in the industry as a flooring material for terraces. There are also other prefabricated blocks or tiles, which have an outer surface of structural material to impart strength and the inside is Sled with insulating materials like glass fiber, mineral wool etc. There are also other materials, like foamed plastic, cork, wood or polyurethane foam etc. which are used as an insulating material.

These structures are expensive and involve expertise in manufacture and installation. The insulating material can be used as a flooring material for terraces and can be used like any ordinary flooring materials without compromising the structural strength. The insulating materials currently in use are porous and have to be incorporated within the structure for protection from weathering and erosion. Further, over a period of time, the pores or air gaps are filled up, resulting in reduction in porosity. The reduction in porosity increases the thermal conductivity of the material and there is a gradual reduction in effectiveness of the material for insulation. There is also a possibility of degradation of the aforesaid materials due to weather conditions. Moreover, they are structurally weak.

BRIEF SUMMARY OF THE INVENTION The present invention obviates the aforesaid drawbacks and provides with a multi-layered tile or block having better insulating properties without the use of the aforesaid insulating materials.

The present invention relates to a multi-layered tile or block comprising of at least three different layers wherein at least one layer comprises of a cementitious material mixed with a fiBer and/or an aggregate.

The use of the different layers controls the ambient temperature inside the building when the said tile or block is installed on the roof, walls or floor.

The thermal insulation capability is dependent on the path length the heat travels through the material. Difference in the layers lengthens the path the heat travels. Therefore, the materials with controlled pore morphology are more thermally insulating than the same non-porous material. Multiple layering imparts much better insulating properties than simply increasing the thickness of any one layer in a two-layered tile or single layered structure.

Difference in the layers reduces or retards the heat radiation or heat transfer to penetrate through the structure. The present invention performs a dual function of preventing the solar radiation from heating up the buildings in hot climates as well as the heat to escape from inside of the building in cold weather conditions.

The difference in the aforesaid layers can be made by varying the chemical composition of the materials or by varying the size gradation of the grains or by incorporating a morphologically dissimilar material.

The present invention incorporates the traditional or known methods of manufacturing the tile or block, wherein the layers are preformed and bonded with cementitious bond or adhesives. Another conventional method is to form the said layers and then compacting them by vibration or application of pressure. The aforesaid layers may be formed using natural or synthetic polymer compounds which also act as binders, fillers and rheology modig agents and other additives like modifiers, lubricants, binders, plasticizers, water proofing compounds, saccharides and polysaccharides etc.

A preferred embodiment of the present invention comprises of a three- layered tile.

More particularly, the first layer of the three-layered tile comprises of a cementitious mixture of hydraulic cement, white cement or grey cement, refractory cement, ceramic cement, natural and synthetic sincates, natural and synthetic phosphates, starches, gums, cellulose and a filler and/or aggregate comprising of natural minerals like marble and calcite, dolomite, talk, mica, granite, silicious stone, calciferous stone, basaltic stone, lime stone, quartz, feldspar, gypsum, selenite and asbestos. Also other man made materials like broken waste ceramic, alumina, steatite, aluminosilicates, magnesite, silicon carbide, compounds of magnesium, compounds of zirconium, calcined or burnt clays, hydrated lime, bauxite, organic or inorganic polymerized materials, plaster of paris, ceramics like vitrified and porous ceramic materials having typical ceramic compositions and mixtures thereof and ceramic process wastes.

The second layer comprises of grey cement with sand and/or basalt/crushed rock grains. The third layer comprises of a same/similar composition as the first layer.

The proportion of the cementitious materials to the total dry weight of all the constituents including the aforesaid constituents is about 50%, preferably about 25-35%.

Alternatively, the second layer comprises of a ceramic material, while the first and third layer comprises of a cementitious material. Further, the first and the third layer may comprise of a ceramic material, while the second layer comprises of a cementitious material In a further embodiment, the exposed surface of the said tile or block is made decorative using colouring agents and/or colouring chips such as crushed stone, glass pieces, ceramic pieces and other decorative polymers.

The present invention may also be formed in-situ.

The present invention will now be explained with reference to the following examples. The examples in no way limit the scope of the invention.

Experiments are carried out wherein any of the following tiles is used: 1. First layer consists of a cementitious mixture of white cement and different grain sizes of marble and dolomite as filler/ aggregate. The second layer consists of grey cement with sand and crushed rock grains. The third layer consists of a similar composition as the top layer.

2. First layer consists of a ceramic tile. The second layer consists of a cementitious mixture of above-mentioned materials. The third layer consists of ceramic.

3. First layer consists of a decorative mosaic of ceramic, glass, stone, and polymer bonded materials, which are embedded in a cementitious mixture of white cement and white marble to form a decorative surface. The second layer consists of a cementitious mixture of grey cement and sand. The third layer consists of a cementitious mixture of white cement and dolomite and marble powder and grains.

The other single layered tile of 20 mm thickness of grey cement and aggregate of sand and crushed stone is taken.

Both the tiles are placed on an insulating foam sheet with slots for placing the thermometer at the bottom of each tile. The said tiles are placed in direct sunlight from morning when the radiation is not very strong. The temperature below both the said tiles is approximately the ambient temperature, viz. about 30 9 C. the temperature at the bottom of the tiles starts rising as the intensity of solar radiation increasing.

Readings were taken at the time of peak ambient temperature viz. 42 ° C. S. No. Particulars Temperature be 1. The bottom surface of the. grey/white cement tile 651 58 2. The bottom surface of the tile at S. No. 1 48 3. The bottom surface of the tile at S. No. 2'45 4. The bottom surface of the tile at S. No. 3 50 Similar testing was done for cold climatic conditions using ice on top of the said tiles. S. No. Particulars Temperature °C 1. The bottom surface of the grey/white cement tile 2 2. The bottom surface of the tile at S. No. 1 10 3. The bottom surface of the tile at S. No. 2 8 4. The bottom surface of the tile at S. No. 3 12 Those skilled in the art will appreciate that various adaptations and modifications of the afore-described preferred embodiment could be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.

Advantages: The following are the advantages of the present invention to the other known art.

1. The structure has better insulating properties; 2. These structures can be used both in summers as well as winters i. e. hot/cold conditions ; 3. These structures are affordable ; 4. They are long lasting ; 5. They are easy to install.