Abstract: Finely-divided particulate additives for polymers with a surface coating comprised of a compound selected from the group consisting of esters of difunctional C.sub.6 -C.sub.40 aliphatic and aromatic carboxylic acids and triesters of phosphoric acid.

Abstract: The ability to maintain a constant differential between modification ratios of trilobal filaments under cospinning conditions is provided by spinning a filament of lower modification ratio through a spinneret orifice consisting of three radially intersecting tapered slots and a filament of a higher modification ratio through a spinneret orifice configured as three radially intersecting reverse-tapered slots. The orifices configured as three radially reverse-tapered slots provide a high modification ratio with low sensitivity to normal spinning process fluctuations which in combination with orifices having tapered slots for filaments of lower modification ratio facilitate maintenance of a more constant differential in modification ratios between the filaments.

Abstract: Improved process control for cospinning synthetic trilobal filaments having different modification ratios is provided by spinning filaments of one modification ratio through spinneret orifices consisting of three radially intersecting slots wherein each slot has parallel sides and spinning filaments of another modification ratio through spinneret orifices consisting of three radially intersecting slots which taper with increasing distance from the center of the orifice. The modification ratio of filaments spun from the orifices having tapered slots is less sensitive to changes in normal spinning process conditions than is the modification ratio of filaments spun from the orifices of slots having parallel sides. This differential response of filament modification ratio to spinning conditions provides better process control of the modification ratio differential between the filaments.