Monofilament yarn—also known as invisible yarn or nylon yarn—as its name suggests, is composed of a single continuous filament. The diameter of this filament is much larger than that of the filaments used in multifilament yarns. As a result, monofilament yarn is relatively stiff and less flexible, and is mainly used in the production of ropes and packaging yarns or twines.

The typical linear density range of these fibers is 75 to 5000 denier. The diameter of monofilament yarns usually falls between 0.08 and 3 mm (80–3000 μm). Diameters of 0.1–0.9 mm are used in the production of textiles and filter fabrics, while diameters of 0.1–0.15 mm are applied in the manufacture of special engineering monofilaments (such as those used in chemical vapor deposition, CVD).

Monofilaments are sold based on yarn count (denier) and tensile strength. To determine the appropriate application, softness and diameter uniformity of the yarn are of great importance.

Table.Comparison Monofilament Yarn vs. Multifilament Yarn

What can be the raw material of monofilament yarn?

Monofilament yarns are produced from thermoplastic polymers. Common polymers used in monofilament production include:

•    Polyamide, including Nylon 6, Nylon 6,6, and Nylon 6,10

•    Polyester

•    Copolyester

•    Polypropylene

•    Polyethylene

•    Polyphenylene sulfide (PPS)

•    Polyvinylidene fluoride (PVDF)

Each of these polymers, depending on their specific physical, chemical, and thermal properties, is used in different applications across industries such as textiles, filtration, medical devices, fisheries, automotive manufacturing, and sports equipment.



 

Table. Comparison Polyester vs. Nylon Monofilament Yarn

Monofilament Yarn Production Process

The monofilament production process is a combination of melt spinning and slit film techniques. In the melt-spinning machine, a melt pump and extruder are installed above the spinneret. Their operation causes relatively thick filaments, with diameters ranging from 0.08 to 3 mm, to be extruded through the fine holes of the spinneret.

These filaments are then cooled in a water bath, after which they are drawn by godet rolls. The molecular orientation stage is achieved by reheating the filaments and stretching them using rollers installed in an oven. Alternatively, heated godet rolls can be used instead of an oven for orientation.
This process results in a more ordered molecular structure, increased tensile strength, and improved mechanical and thermal properties of the monofilament yarn.

Cross-Sectional Shapes of Monofilament Yarn

Monofilament yarns are produced with various cross-sectional shapes, including circular, triangular, star-shaped, hollow, and grooved profiles.

•    For woven fabrics, monofilaments with a circular cross-section are typically used.

•    Hollow or shaped monofilaments are employed when lower weight, greater softness, or improved hand feel is required.

•    Filaments with non-circular cross-sections are commonly used in the production of nonwoven fabrics.

One of the main reasons for producing monofilament yarns with different cross-sectional shapes is to impart specific characteristics, such as:

•    Flexibility and bending stiffness

•    Contact area and friction

•    Optical properties / transparency

•    Packing density and permeability in meshes (nets)

Mechanical and Physical Properties of Monofilament Yarn

•    High bending stiffness (low flexibility) compared to multifilament yarns

•    Low bulk and low compressibility

•    Shrinkage: Some monofilaments (especially nylon) shrink when exposed to heat. The maximum reported shrinkage for nylon monofilament is around 10%, while typical values for monofilaments made from other materials are reported to be 3–4%.

•    Low bending-to-break ratio in coarse (thick) monofilaments

♦ References

► https://textile-yarn.com

►https://textile-yarn.com

♦ Link

► B2n.ir/nassajyar1943

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