Additives for Polymers October 1993

Effect of surface treating pigments in colour concentrates

Although equipment and TiOz concentration are major influences, the ease with which the pigment disperses can be selectively controlled by the type and amount of surface treatment. To selectively influence dispersibility, TiO, suppliers have long treated pigment surfaces with inorganic substances, such as hydrated aluminium oxide and hydrated silicon oxide, and with organic compounds such as polyal~ohofs or polysiloxanes. Other steps in the process of pigment production, such as type and intensity of grinding, also effect dispersibility of TiO, pigments in colour concentrates.

This study involved extensive laboratory work as it investigated the influence of organic surface treatment on the processability of TiO, pigments in the formulation of concentrates in LDPE. Two different laboratory devices - an internal mixer and a twin-screw extruder -were employed. Results show that in the manufacture of colour concentrates in LDPE, the processability of TiO, pigments is, on the one hand, clearly dependent on the type of machine used and the dispersion conditions. On the other hand it is closely connected with the composition of the TiOz concentrates. Beyond this, however, concentrate manufacturers can selectively control processability of TiO, pigments in their products through the type and amount of surface treatment used on the pigment. Plastics Engineering, 1993, (July), 19-22.

COMPANY NEWS

Akzo-Harcros form joint venture company

Following the provisional announcement in the May 1993 issue of Additives for Polymers, it is learnt that Akzo NV and British firm Harrison & Crosfield (Harcros) have established a joint venture for PVC

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additives called Akcros Chemicals.

The joint venture’s headqua~ers will be in Eccles, UK, and it will have plants in the UK, the Netherlands, Germany, France and USA. Akzo and Harcros formed the venture from a part of each company’s organic chemical interests. Contact: Akzo Chemicals BV, Stationsstraat 48, NL-3818 L W Amersfoort, Holland. Tel: +31-33-064-3911.

Ciba plant to manufacture antioxidant intermediate

Ciba has completed a new 15000 tonnes/year plant for the manufacture of Metilox, an intermediate used to manufacture antioxidants for the plastics industry. The unit is located at the group’s Kaisten works in Switzerland and will begin full scale manufacture at the end of this year. Contact: Ciba-Geigy Additives, Huller Road, Macclesfield, SKI0 2NX, UK. Tel: +44-625- 66500. Fax: i- 44-625-502674.

Great Lakes Chemical purchases Chemische Werke towi

Great Lakes Chemical, the US brominated chemicals’ manufacturer, has bought Chemische Werke Lowi of Waldkraiburg, in Germany. Lowi is a leading manufacturer of antioxidants and UV absorbers, serving not only the plastics industry but the rubber and adhesives industries as well. Contact: Great Lakes Chemical Cop, PO Box 2200, W. Lafayette, IN 47906, USA. Tel: +I-337-463-2511.

Another pigments plant for Miles

Miles Inc in the USA is now operating a new organic pigments plant at the company’s manufacturing complex in Bushey Park, near Charleston, South Carolina. High performance products manufactured by Miles include Perrindo, Qujndo and Palomar

01993 Elsevier Science Publishers Ltd