Nylon Thread: Melt-Spun Monofilament, Cold-Drawn Between Two Drums, Carothers

Nylon sewing thread is a single clear strand, a monofilament. Carothers' patent (1938) spins nylon 66 straight from the melt at 285–295 °C, with oxygen kept out, and catches the strand on a drum. A second, faster drum then stretches it (cold drawing), which makes it strong. The picture: our own drawing.

متقدم

1 day

التعليمات

Load the pot under nitrogen

Fill the melt-spinning pot with dry nylon 66 pellets and close it. Flush it with nitrogen and keep it under nitrogen: oxygen must stay out of the molten polymer.

المواد لهذه الخطوة:

حبيبات النايلون500 غ

الأدوات المطلوبة:

وعاء غزل بالصهر

نيتروجين

أسطوانة غاز مضغوط

Melt at 285–295 °C

Heat to 285–295 °C, the best spinning heat for nylon 66. Cooler gives poorer filament; hotter makes it too runny, and it may break down.

الأدوات المطلوبة:

وعاء غزل بالصهر

مزدوجة حرارية بقارئ

Extrude and catch it

Press the melt out through the hole with nitrogen pressure (Carothers' example used 50 lb/in²). Catch the strand on a motor-driven drum. A larger hole gives a thicker strand; hotter melt and faster winding give a finer one.

الأدوات المطلوبة:

نيتروجين

أسطوانة غاز مضغوط

أسطوانة سحب

محرك كهربائي

Cold-draw onto a faster drum

Run the strand from the first drum onto a second drum turning faster, which stretches it. In Carothers' example the drums ran at 300 and 1020 ft/min. Keep the strand wet: wet filament draws better and holds no static.

الأدوات المطلوبة:

أسطوانة سحب

محرك كهربائي