Vol. 19, No. 12, Page 2

TECHNICAL NOTES

FOLYI'ER-BOUND STABILIZERS

The Lucid01 Div. of Pennwalt Corp., Buffalo, N.Y. has developed methods for making UV stabilizers and antioxidants "chemically reactive" with polymers, which should eliminate the problems of migration or extraction, etc. The company has been granted five patents on the preparation and use of polymer-bound hind- ered amine lightstabilizers (HALS), UV absorbers such as benzo- phenones, and antioxidants; five other patents are expected to be granted, and 13 more patent applications on polymer addi- tives are pending.

Among several developmental products is Lupersol HA-505, a per- oxide-functional HALS that can be used in high-solids acrylic coatings and can also be incorporated into polystyrene during polymerization. Lucid01 UV-MPC is a peroxide-functional benzo- phenone that could also be incorporated into polystyrene. Lu- them HA-R100 is a hydrazide-functional HALS that can be incor- porated into nylons, polyesters, or polycarbonates during poly- merization. Its HALS functionality is supplemented by the addi- tional UV-stabilizing function of the hydrazide functionality, and by metal-deactivating oxamide functionality. HA-R100 and other hydrazide-functional stabilizers can also react with mal- eic anhydride-grafted polyolefines. Lucid01 is sampling a prod- uct called Luchem HA-B18, which is a UV-stabilizer "concentrate" compatible with polyolefines, made by reacting HA-R100 with an octadecene maleic anhydride copolymer.

Plast. Tech., 1989, 35, (Aug.), 13

CAVITY TRANSFER The use of Cavity Transfer Mixers (CTMS) developed in the UK MIXERANDTHE by RAPRA Technology, on both single and twin screw extruders COLOURING OF has led to the development of liquid injection into the melt PLASTICS of the CTM cavities. This allows liquid colours to be incorpor-

ated into the polymer melt without contaminating the extruder barrel.

RAPRA has now developed a simple process for skin colouring products extruded from in-line straight-through dies which, in contrast to the cable processes, uses the feedblock principle. (See also next item). In this latest development, most of the polymer is by-passed through a hole in the centre of the CTM rotor, when liquid colour is used, the laminar flow patterns keep the coloured layer on the outside of the central natural polymer all the way from the CTM exit/feed block through the adaptor and the die. Applications for this process are not con- fined to skin colouring; it could, for instance, be used to ap- ply antistatic agents or adhesives to the surface.

British Plast. & Rubb., 1989, (June), 17

Cont./......

ADDITIVES FOR POLYMERS

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