Industrial monofilament is a high-strength, coarse filament with a fineness of at least 550 dtex. Polyester (PET) industrial monofilament has excellent properties. It has high dry and wet strength, high modulus, low elongation, and good fatigue resistance. It is widely used in tire cord fabric, conveyor belts, tarpaulins, automotive seat belts, and advertising lightbox fabrics.
1. Advantages of Flame-Retardant Monofilament Used Our Chips
1.1 Excellent Flame-Retardant Properties
Our flame-retardant monofilament has a limiting oxygen index (LOI) of 35% or higher. It does not drip when burning.
I have previously written an article about LOI titled Understanding Flame Retardancy: Oxygen Index vs. UL94 Ratings, details are here.
1.2 High Strength
The fiber has a breaking strength of over 6 cN/dtex and can reach up to 8 cN/dtex.
1.3 Color Additives
It can include color, eliminating the need for secondary dyeing.
2. Structure of Flame-Retardant Polyester Monofilament
The addition of copolymer units reduces the crystallinity and orientation of the amorphous regions. This affects the mechanical properties of the monofilament.
3. Flame-Retardant Performance
Our strongest flame-retardant polyester monofilament has an LOI of 30.9%. It shows excellent self-extinguishing properties and resistance to sustained burning.
4. Preparation Method
The low molecular weight flame retardant copolyester is blended with the high molecular weight polyester for spinning. The glass transition temperature is 65-73°C. The melting point is 258-266°C. The intrinsic viscosity is 0.61-0.67 dL/g. The number average molecular weight is 18500-21000 g/mol. The molecular weight distribution index is 1.9-2.2.
5. Features of Flame-Retardant Chips
We use active phosphorus-containing flame retardants and polyester chips as raw materials. The chips are made through melt blending and stepwise solid-phase polymerization. Its melting temperature is 250-260℃, melting enthalpy is 52-65kJ/g. Its intrinsic viscosity is 1.05-1.25dL/g. Its average molecular weight is 35000-45000. Its PDI is 1.05-1.08. Its phosphorus content is 0.1-2.0wt%. Its LOI is 28-36%.
6. Importance of Developing High-Performance Flame-Retardant Polyester
The development of high-performance flame-retardant polyester chips solves the current deficiencies of flame-retardant copolyester fibers in terms of strength and flame retardancy. At present, phosphorus-based flame retardants such as CEPPA, DDP, DOPO, HMPPA, etc., result in low fiber molecular weight (less than 0.45dL/g) and poor mechanical properties. Adding a large amount of flame retardants makes it difficult to process and has low performance. This ultimately leads to polyester fiber strength below 6.5cN/dtex.
For military ropes, belts, flexible oil bladders, etc., the fiber strength is required to be above 7.0cN/dtex and the heat shrinkage rate is low. Military tents, flexible gun holsters, etc. also require strength, flame retardancy and flexibility. The nylon and aramid fibers currently used by the military are expensive. He also has the disadvantages of heavy weight and high cost. These limit the flexibility and scalability of equipment.
The new high-performance flame-retardant polyester chips can improve fiber strength and flame retardancy to meet military needs. It reduces costs and improves overall performance. This improves the modernization and competitiveness of military equipment.
