1-Specific Tests Applied to Slub Yarns
Slub yarn is one of the most well-known and most produced yarn types in the fancy yarn group.
The term slub yarn refers to yarn containing intentionally created yarn irregularities due to changes in yarn twist and/or yarn mass (thick or thin place).
Slub yarns; These are the yarns obtained by forming thick parts randomly or in accordance with a certain pattern (pattern) at different intervals on the yarn as single or ply.
These thick areas formed on the yarn are called slub or fish. The size (thickness, length, shape), repetition range, color and fiber type of slubs can vary. The simple structure of a slub yarn is shown below.
As seen in this figure, the basic yarn count (Ne2) is at a certain value and does not change in the regions between the slubs along the yarn. In the slub parts, the number (Ne1) changes according to the desired slub thickness. The twist amount (T) remains constant throughout the yarn, while the twist factor α (twist coefficient) is variable. That is, α1 ≠ α2 Slub yarns are divided into two classes among themselves.
1-ground slub yarns
2-compound or multi-component slub yarns.
Ground slub yarns; It is obtained by forming slub parts as part of the basic yarn by changing the draft while producing a single ply yarn in yarn spinning systems.
Compound (multicomponent) slub yarns; Spinned yarn, filament, roving, strip etc. with different properties in spinning or twisting machines. It is obtained by combining materials and twisting the roving or strip in them by providing intermittent feeding to form a slub.
In ground slub yarnsSince the slub parts are part of the basic yarn, different visual structures (effects) can be obtained in the fabric by making changes in the dimensional properties and layout of the slubs. Examples of slub structures obtained in this way are given below.
In addition to slub yarn production in ring spinning and open-end rotor spinning machines, some appropriate changes were made; variable number or multi-count yarns, variable twist or multi-twist yarns, variable effect or multi-effect yarns Various fancy yarn types such as slub yarns are also produced. Due to the widespread use of slub yarns, studies have focused on determining production standards and quality control applied to yarns. The following problems are frequently encountered in the slub yarn production stage in the enterprises.
Slub yarns that do not meet the standards, the desired slub pattern is not produced correctly, periodic errors in normal yarns, incorrectly entered slub pattern information, unusual mass loss at the beginning or end of the slub, missing slub along a certain length on the yarn, etc.
Quality parameters of slub yarns can be examined under two groups; These are technical and visual quality parameters.
Slub length (length): The distance between the start and end points of a slub.
Slub thickness coefficient: It is the ratio of the slub linear density to the basic yarn linear density.
Slub range: It is the distance between the end point of one slub and the starting point of the next slub.
Unit pattern layout: It is a plan chart that reports the length, thickness and spacing values of slubs that are placed consecutively within the unit pattern pattern.
Unit pattern length or report length: Slub is the total length of the unit pattern pattern that repeats throughout yarn production.
Slub length, slub spacing, etc. of the slub yarn. Dimensional properties are measured manually with the help of a ruler on a black background.
2-Specific Tests Applied to Chenille Yarns
Fixing (compressing) the pile formed by folding together 2 high twisted, thin and durable yarns called chenille yarn, lock yarn and cutting a spun or filament soft twisted yarn (pile yarn) with a given twist along the length of the basic yarn formed. basis. Short fibers are called pile (effect), and high twisted yarns are called basic (core-core-lock) yarn. The resulting yarn has a velvety and pile appearance.
Pile Yarn is the yarn that adds aesthetic value to the chenille yarn and determines the surface appearance. While providing volume to the yarn, it constitutes 70-75% of the structure in terms of mass. A yarn spun from short-length fibers or filament soft twisted yarn is used as pile yarn. Then, the pile of the pile yarn, which is cut in short length, is thrown between the lock yarn and the chenille yarn structure is formed. Pile yarn does not have a solid structure. When fabric is produced from chenille yarns, the effect yarns remain on the fabric surface and give the fabric a different appearance. The lock thread is the thread that holds the pile cut from the pile threads, thanks to the twist on it. The chenille gives strength to the yarn and constitutes 25-30% of the yarn mass.
3-Specific Tests Applied to Flock Yarns
flock yarns; They are obtained by the principle of electrostatic flocking and consist of a core yarn, an adhesive applied on this material and electrostatically charged flock fibers. The core yarn is located in the center of the flock yarn and acts as a carrier material. In order to have sufficient tensile strength, abrasion resistance and a good handle, its total number should be between 140 - 1260 denier. The adhesive material is wrapped around the core yarn in the form of a film layer and should be chosen in such a way that it can combine (combine) the core yarn and flock fibers strongly and not weaken the flexibility and handling of the flock yarn obtained. The flock fibers form the outermost layer of the flock yarn and are stuck on the adhesive coating coated on the core yarn. The cut lengths of the flock fibers are preferably between 0,3–5,0 mm.
The most important factors that determine the quality properties of flock yarns, which have a different production process than standard yarns, are flock density (the number of flock per unit area) and abrasion resistance, which determines the degree of adhesion of the flocks to the main yarn. The Yarn Abrasion Test method used for chenille yarns can also be used for flock yarns. Alcohol test can also be applied for visually subjective assessment of yarn wear.
4-Specific Tests Applied to Other Fancy Yarns
Apart from slub yarn, chenille yarn and flock yarns, there are many fancy yarn types such as loops, folds, knots, curls, frieze, knitting type yarns. In addition to standard yarn tests, tests can be applied to these yarns after surface formation such as weaving and knitting according to their usage areas.