Why is a spinneret used to make nylon but is not needed to make cotton or wool fibres?
Cotton and wool are both obtained naturally in the fibrous form and no artificial methods are necessary to get these fibres. In contrast, nylon is a synthetic fibre obtained from plastics derived from petroleum. The plastic is first melted at high temperature and then forced out through a device with many holes in it known as a spinneret. Since, nylon is developed from plastic, a spinneret is needed to make nylon fibres.
Living Science (2020, 2021)