Question

discuss how moulded tiles on composite materials are manufactured, especially polypropylene(Pp) tiles (2000 words)

Answer 1

A process for manufacturing a composite tile from waste thermoplastic material comprising the steps of:

(a) crushing the waste thermoplastic material;

(b) injecting a virgin plastic material into a mold between a cavity formed by a primary punch and a matrix associated with said mold to form the first layer of said tile;

(c) rotating said mold after said injecting step to reverse the position of said matrix and of said primary punch;

(d) replacing said primary punch with a secondary punch to form a cavity between said first layer, supported by said matrix and said secondary punch; and

(e) injecting said waste thermoplastic material into said cavity to form a second layer of plastic material arranged upon said first layer of said tile.

This present invention concerns a manufacturing process and a composite tile of plastic material obtained by said process.

The plastic materials composed of the waste of some industrial processes (for example in the shoe-making sector), and/or coming from plastic objects of current use being put out of use, are frequently crushed to be used again in subsequent transformations.

The latter recovery operation, however, is not always cost-effective and possible as the crushed material in some cases assumes such poor properties that it is not possible to use it again not even in the manufacture of low quality products.

As a consequence of this it is known that much plastic waste is accumulated in landfills, causing considerable storage problems as it cannot be burned due to the environmental pollution that would ensue from its combustion process.

The purpose of this present invention, as characterised by its claims, is therefore to eliminate the above mentioned drawbacks.

The usage of clay roof tiles waste as a filler in composite was studied. Polypropylene (PP) composites of clay roof tiles wastes (CRTW) for low strength applications were prepared at filler contents 5%, 10%, 15%, 20%, 25% and 30%. Unfilled PP used as reference sample. The clay roof tiles wastes were prepared to achieve 45 micron in size to mix with PP. The composites were mixed using double hot roll mill mixer at temperature 190°C. The final products of the composites prepared were in a granul form which undergone granulation process after mixing. Injection moulding process also conducted to get the composites in dumbbell shape. The mechanical and thermal properties of the composites prepared were determined. Results showed that the CRTW improved the hardness properties and melt density with the increases in the filler content. On the other hand melt flow index was however observed to decrease with increases in the filler content. For the thermal properties at maximum loading of filler content it shows the maximum temperature of weight loss rate, Tpeak and the onset decomposition temperature, Tonset higher compared to unfilled PP. The tensile properties for ultimate tensile strength, elongation at break, break strain percentage, maximum load and toughness were however also observed to decrease with increases in the filler content.