Abstract: A method of imparting heat resisting properties to synthetic plastics materials comprises incorporating in the material an organic antioxidant each molecule of which contains a reactive hydrogen atom and does not become an oxidation radical when the hydrogen atom is replaced by a free radical obtained from the polymer.

Abstract: An apparatus providing a hot section in a continuously moving synthetic yarn wherein at least one jet of hot fluid obliquely is directly across the moving yarn. The jet intersects the yarn at an obtuse angle to the approaching yarn. The apparatus also produces drawn yarn by passing undrawn yarn into the jet and tensioning the yarn as it passes through the jet. The apparatus includes a body member formed with a chamber formed with yarn entry and exit passages and a fluid ejecting nozzle. The body member may be additionally formed with a cavity opening from the chamber opposite the nozzle.

Abstract: A method of providing a hot section in a continuously moving synthetic yarn comprises directing at least one jet of hot fluid obliquely across the moving yarn. The jet intersects the yarn at an obtuse angle to the approaching yarn. The method also produces drawn yarn by passing undrawn yarn into the jet and tensioning the yarn as it passes through the jet. Apparatus for performing the method includes a body member formed with a chamber formed with yarn entry and exit passages and a fluid ejecting nozzle. The body member may be additionally formed with a cavity opening from the chamber opposite the nozzle.

Abstract: A method of producing commercially usable textured synthetic multifilament yarn from commercially produced undrawn multifilament synthetic yarn of a type which has normally a limited operational life and which has exceeded the normal operational life for undrawn yarn in which the overage undrawn yarn is fed continuously without pause through two discrete successive treatments with hot fluid at a temperature high enough to plasticize the yarn. The yarn is drawn to a chosen ratio of extension while it is passing through the first treatment with hot fluid. Next the yarn is jet textured while it is passing through the second treatment with hot fluid. The yarn may be subjected to a cooling action between the two successive treatments with hot fluid.

Abstract: A bulked multifilament yarn having filaments of polymeric material has alternating points of maximum polymeric density and minimum polymeric density occurring along the length of each filament with a maximum spacing of 10 meters. The yarn may have a crimped structure in which the crimps are of undulating form with more than 50% of the filaments having maximum amplitudes of undulation less than the diameter of the yarn and more than 50% of each filament lies on one side of a diametral plane of the yarn particular to that filament. A process of producing the yarn includes the steps of jet bulking yarn and projecting it against one end of an elongated package during which the pressure prevailing at said one end of the package fluctuates. The pressure varies between a maximum value and a minimum value with a frequency related to the rate of feed of the yarn.