Microspheres filler polyester resin

The materials employed for making hollow microspheres include inorganic materials such as glass and silica, and polymeric materials such as epoxy resin, unsaturated polyester resin, silicone resin, phenolics, polyvinyl alcohol, polyvinyl chloride, polyjM-opylene and polystyrene, among others, commercial jx oducts available are glass, silica, phenolics, epoxy resin, silicones, etc. Table 36 shows low-density hollow spheres. Table 37 shows physical properties of glass microspheres, and Table 38 shows comparison of some fillers on the physical properties of resulting foams (10). 

Figure 16.13. Viscosity of polyester resin filled with calcium carbonate and microspheres (total content of filler (CaCOs+microspheres) is 60 wt%). [Data courtesy of Abrasivos Y Maquinaria, SA, Barcelona, Spain] ...

Syntactic foamed plastics (from the Greek ovvxa C, to put together) or spheroplastics are a special kind of gas filled polymeric material. They consist of a polymer matrix, called the binder, and a filler of hollow spherical particles, called microspheres, microcapsules, or microballoons, distributed within the binder. Expoxy and phenolic resins, polyesters, silicones, polyurethanes, and several other polymers and oligomers are used as binders, while the fillers have been made of glass, carbon, metal, ceramics, polymers, and resins. The foamed plastic is formed by the microcapsular method, i.e. the gas-filled particles are inserted into the polymer binder1,2). 

Fire resistance is an important property of phenolic resins. The combination of phenolic resin with Expancel expandable microspheres leads to many useful products. Composites for high speed train interiors take advantage of the light weight, excellent fire rating, and very low thermal conductivity. Polyester filled with aluminum hydroxide is an alternative solution for train interior materials. The resin and filler can be easily processed when viscosity regulating additives are added. 

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