High Purity Silica Offers Ideal Combination for Film

High Purity Silica Offers Ideal Combination for Film

Low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and polypropylene high clarity grade packaging and commercial film is benefiting from the ideal combination of refractive index and particle morphology offered by Minbloc® M grades of silica, claims the manufacturer Sibelco.

The Belgian company says that the Minbloc M grades offer a refractive index of 1.48. Produced from a high purity silica feedstock, the M series is said to deliver chemically inert antiblocks with low soluble metals and trace elements. According to Sibelco, thermal treatment at 1500°C sterilizes and produces the refined M series with an expanded crystal structure and an ideal morphology for effective antiblock and reblocking properties.

Sibelco says that all Minbloc grades are produced in statistically controlled manufacturing environments to control top and bottom particle sizes precisely. This delivers specific surface areas and size distributions that are optimized for flexible film applications. The absence of coarse particles helps prevent film distortion and eliminates potential sources of surface irregularities.

The balanced content of ultrafine particles reduces their contribution to haze but promotes the formation of crystallites and improves the film properties through nucleation. The company claims that the ultra low surface porosity of Minbloc avoids absorption and inactivation of other additives, such as erucamide and oleamide.

Minbloc performs as an infrared absorber in the 7-14 micron wavelength range and acts as a thermal barrier to retain captured light energy. In agricultural LDPE, LLDPE and PP film this is said to translate into a greater transmission of direct and indirect light, and higher retention of irradiated temperatures. Minbloc grades are also claimed to allow considerably more direct light transmission, which improves the visibility through the film and makes optical control of growth under the greenhouse film easy. Minbloc is certified for direct and indirect food contact applications.