Flake yarns, also known as flock yarns, are usually single yarns in which small tufts of fiber are inserted at intervals and held in place by the twist of the base yarn. The result is a flake yarn of varying thickness and softness, caused by the soft effect ply held in place by the uniform binder. These may be round or elongated. Flock yarn is used for fancy effect uses.
Spiral or corkscrew yarns are complex yarns in which the desired effect is obtained either by twisting together yarns of different diameters, different sizes, or different fiber content, or by varying the rate of speed or the direction of twist. The spiral yarn consists of two yarns of different size: one fine with a hard twist, the other bulky with a slack twist. The heavy yarn is wound spirally around the fine yarn. Fine yarn is also known as core yarn. A corkscrew yarn can be made by twisting together two yarns at an uneven rate, by twisting together two yarns of different size, or by twisting a fine yarn loosely around the heavy yarn so it gives the appearance of a corkscrew. Spiral yarns have more elongation than other types of yarns. Sometimes, the core yarn is completely hidden by the spiralling outer yarn, as in the case of Lastex where the core yarn is rubber while the outer yarn maybe of cotton, nylon or other textile.
Ratine and gimp yarns are very simple to each other and, in addition are rather like boucle and loop yarns. The major difference between boucle and ratine or gimp yarns is that the loops are close together in ratine or gimp, while in boucle they are more widely spaced. The structure is similar, in that the yarn forming the loops is wrapped around the base yarn and then held in place by a binder or tie yarn. The ratine yarn shows a taut, rough surface effect in overall appearance. The term gimp is used frequently as a synonym for ratine. When a distinction is made, a yarn that has the loops formed by a very soft and slacky twisted yarn is referred to as a gimp yarn, while the loops on the ratine yarn are of a soft but securely twisted yarn.
Boucle or Loop or Curl Yarns
Boucle yarns are characterized by tight loops projecting from the body of the yarn at fairly regular intervals. These yarns are of 3-ply construction. The effect yarn that forms the loops is wrapped around a base yarn, and then a binder or tie yarn holds the loops in position. Boucle fabrics can be constructed by either knitting or weaving. The yarn is also available for hand knitting.
Nub, Knot or Knop, and Spot Yarns
The terms nub, knot, knop and spot are often used interchangeably; however, there are minor differences between nub and knot yarns. A nub yarn (sometimes called a spot) is a ply yarn. It is made on a special machine that holds the base yarn almost stationary while the effect yarn is wrapped around it several times to build up a nub or enlarged segment.
Chenille yarns are used for special effects in fabrics and in the manufacture of chenille rugs. The yarn resembles a hairy caterpillar –chenille is French for caterpillar. It has a soft, fuzzy, lofty (springy) surface. The effect is achieved by a core of two yarns plied together and firmly holding short tufts of soft twisted yarn between the twists along the core’s length. The result is a yarn with a velvet like or pile surface.