In order to produce rugged, low-cost products made of plastic, fillers are mixed into the molten plastic while it is passing through the extruder. The new DORVALIT® SHA and DORVALIT® SFA functional fillers are an ideal choice for giving added strength to polyamide (PA).
DORVALIT® SHA and DORVALIT® SFA are REFINERALS®-class fillers made by Dorfner. They are produced from refined kaolins with a surface treatment. The organic residue attached to the surface has special functional polar groups which are very important. They form covalent bonds with the PA matrix, which results in good intermeshing between the filler and the plastic. It also ensures very good wetting of DORVALIT® SHA and DORVALIT® SFA particles by molten PA in the extruder and gives the particles good processing characteristics. This results in excellent dispersion of DORVALIT® SHA and DORVALIT® SFA in the molten plastic and consequently in a fine, homogeneous distribution in the finished injection-molded part. When DORVALIT® SHA and DORVALIT® SFA are used, molten polyamide has very good flow properties and it is possible to produce delicate parts with very fine details. In addition, DORVALIT® SHA and DORVALIT® SFA fillers are compatible with all other constituents in a PA matrix and have extremely high thermal stability.
DORVALIT® SHA and DORVALIT® SFA are innovative new products which disprove the widely held conviction in the industry that filler particles for polyamide must necessarily be small. The opposite is actually the case. The relatively large mean particle diameter of DORVALIT® SHA (6 µm) and DORVALIT® SFA (3.5 µm) together with the surface modification and the resulting high material quality of the plastic parts are the crucial factors. DORVALIT® SHA and DORVALIT® SFA are easy to feed and process. There is no tendency to form lumps during storage or when the fillers pass through feed screws at the extruder, as is often the case with ultra-fine fillers for plastics.
It is well worth considering DORVALIT® SHA and DORVALIT® SFA during selection and testing of fillers in the plastics industry. There is no point in waiting. To request your lab sample, contact us today at this e-mail address: customerservice.1 (at) dorfner [punkt] com.