Polymer Contaminant
Transparent sheet material used in packaging poses a high risk to textile processing because it blends visually with the cotton stock. A clear synthetic film is generally composed of polyethylene or polypropylene used to wrap high density bales during transit. Its absence of color allows it to pass through standard optical scanners that look for discolored trash.
Detection requires specialized electromagnetic sensors or polarized filters.
Geometric Property
Tensile strength is high in these materials compared to the soft fibre mats that surround them. Once a piece of clear synthetic film enters the feeder, it tends to shred into elongated strips that foul the spinning rotor. These fragments wrap around rotating shafts and increase friction.
Inspection Variable
Because cotton is highly absorbent and the film is non-porous, moisture meters sometimes identify larger pieces through conductivity variance. Accurate clear synthetic film removal relies on air jets synchronized with a high speed camera tracking the vertical drop of the lint. The time lag between vision and action must be minimal.
This is measured in milliseconds to avoid wasting good material.
Processing Consequence
Undetected scraps melt during heat intense finishing steps, creating hard beads in the woven fabric. A small film strip can contaminate several rolls.
