Single-filament Fineness
Single-filament fineness is an index that indicates the thickness of each filament making up a multifilament yarn. It is generally calculated by dividing the total fineness by the number of filaments, and it is a value related to hand feel, luster, and texture.
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Definition and Calculation Method
Single-filament fineness is the thickness of one filament in a multifilament yarn made by bundling multiple continuous filaments. It is usually expressed in dpf, where d means denier and pf means per filament.
In general, it is calculated by dividing the total fineness by the number of filaments. For example, even with yarn of the same total fineness, the more filaments it has, the smaller the single-filament fineness becomes. Single-filament fineness indicates the fineness of the constituent filaments, not the overall thickness of the yarn.
- Single-filament fineness = total fineness ÷ number of filaments
- Total fineness is the thickness of the yarn as a whole; single-filament fineness is the thickness of each constituent filament
Effects on Texture and Appearance
When many fine filaments with a small single-filament fineness are used, the surface generally becomes smoother, and it is easier to achieve suppleness, softness, and a delicate luster. In woven and knitted fabrics, it tends to look denser and also affects drape.
When the single-filament fineness is larger, depending on the material and processing, it may provide firmness and a crisp touch. Texture is not determined by single-filament fineness alone; it should be evaluated together with resin type, cross-sectional shape, twist, density, weave or knit structure, and finishing.
Main Applications
Filament yarn with a fine single-filament fineness is used for lightweight, soft blouses, linings, dresses, and lightweight sports apparel. It is also used in spring and summer fabrics that require a delicate surface feel and lightness.
Filament yarn with a relatively coarse single-filament fineness may be used for taffeta, bag fabrics, outerwear, uniforms, and similar items that require moderate firmness and durability. However, applications vary greatly depending on total fineness and fabric design.
Selection and Handling Notes
When selecting fabric, check not only the single-filament fineness but also the total fineness, number of filaments, fabric weight, density, and structure. Even with the same single-filament fineness, if the total yarn fineness differs, the fabric thickness, strength, and sheerness will not be the same.
Thin fabrics made with ultrafine filaments may show seam slippage, puckering, needle holes, and snagging more easily. During prototyping, choose a fine sewing thread and an appropriate needle, and check thread tension, feeding, and stitch conditions.
Shrinkage and dimensional change after washing cannot be judged from single-filament fineness alone. Since they are affected by fiber type, processing such as heat setting, structure, and washing conditions, it is important to perform washing and sewing tests in advance.
Differences from Similar Terms
Total fineness is the thickness of the yarn as a whole, and it should be distinguished from single-filament fineness. The term "total fineness" is sometimes used as another name for single-filament fineness, but technically they are not the same. In specifications, listing the total fineness and number of filaments together helps avoid confusion.
Denier is a unit used to express the thickness of fibers and yarns. dpf is a notation that shows denier per filament. Count is mainly used for spun yarns as an indicator of thickness, and the relationship between larger or smaller numbers and thickness depends on the notation system.
Frequently Asked Questions
What is the difference between single-filament fineness and total fineness?
Total fineness is the thickness of the entire multifilament yarn, while single-filament fineness is the thickness of each filament that makes up that yarn. Even if the total fineness is the same, the more filaments there are, the smaller the single-filament fineness becomes, and the surface feel and softness may change.
Does a smaller dpf value always make the fabric softer?
In general, finer filaments tend to produce a smoother and more supple texture. However, fabric softness is also affected by total fineness, twist, weave or knit structure, density, processing, and the fibers blended with it, so dpf alone is not enough to make a judgment.
Can shrinkage after washing be determined from single-filament fineness?
Shrinkage cannot be predicted from single-filament fineness alone. Shrinkage is affected by fiber type, heat treatment and finishing, structure, density, sewing specifications, and washing and drying conditions. Before commercialization, washing tests should be performed on both the fabric and the sewn product.
