poly-ester resin versus epoxy resin

Polyester resin, the composition and the performance

The poly-ester resin in stone industry is in fact the same unsaturated polyester resin which is the combination of the unsaturated polyester itself and a monomer usually a styrene monomer. This two-element compound react immediately in the presence of Methyl Ethyl Ketone Peroxide (MEKP) as a curing agent added with a catalyst (usually cobalt), resulting in some long polymeric bonds. The product of this reaction, as it was discussed in epoxy resin , passes through the liquid phase by releasing a great amount of heat and starts the gelling phase to subsequently acquire the solid state.

Polyester resin in stone industry

In the stone industry and for processing the natural stones, the raw polyester resin is employed and depending on the desired color tone and the stone background, it is mixed with some mineral pigments in order to get the same color as the working background. To explain this, Mustic is the same polyester resin mixed with the filler powders in addition to the mineral pigments which is widely used in order to fill the pore spaces in especially travertine (Slab or Tile).

What is the difference between polyester resin and epoxy resin?

The most important difference between polyester resin and epoxy resin is in fact the ultimate mechanical strength that each resin develops so that it measures 13-14 MPa for polyester resin whereas for the epoxy resin it is 50-60 MPa. The other significant difference relates to the permeability so that the epoxy resin epoxy resin is the only suitable and workable resin in processing the hair cracks and fracture lines as it has so much higher permeability comparing to the polyester resin. The third important difference between them is that the epoxy resin presents so much higher polishing quality in the processing operations.

The steps for applying polyester resin on the stone

Considering that the curing time for polyester resin is quite lower than for epoxy resin , it is appropriate to pre-heat the stones through the in-line heating fans after the calibrating processing. In the next step, the polyester resin is applied by special applicators onto the surface of the Tile or Slab, and subsequently the stones will be processed by means of the abrasives to the final stone finish .