Protos FIL

Protos Fil

Fire retardant, para-aramid continuous filament.sewing thread

Coats Protos Fil is a fire retardant 100% para-aramid continuous filament sewing thread.

This thread offers excellent thermal resistance and protective seam durability in applications exposed to high external heat.

Para aramid filament is very difficult to dye, but Coats has developed a unique and innovative dyeing process to offer Protos Fil in a range of colours suitable for the mattress industry.

Protos Fil meets both American Fed 16 CFR 1633 Mattress Burn Test and Military AA 55220 specification requirements.

A special coating is applied to the fibre in order to maximise sewing performance even in the most exacting operations. Coats Protos Fil is the recommended thread for mattress tape edge seams.

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Military backpack

Features and Benefits

  • Delivers a higher margin of mattress burn test safety because of higher para-aramid filament tenacity
  • Retains adequate strength even after heat ageing up to 400°C for 30 minutes
  • Unique monocord cross section available in lightly bonded version
  • Special para-aramid colours available
  • Excellent sewing and exceptional seam integrity
  • High strength and low elongation for ripcords


Since conditions and applications vary considerably in the use of a product, the customer and/or user should assure herself or himself that the product meets end customer requirements and is suitable for the intended end use. Coats accepts no liability for unsuitable or improper use or application of products.

Information provided above is based on current averages and should be taken only as indicative. Coats accepts no liability for the preciseness and correctness of the information provided.

Product information sheets are updated from time to time, please be sure you are referring to the most recent publication. Coats supports customers with advice on individual applications on request; if you have any questions or concerns, please contact us.