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Chenille Background
Chenille Yarn
For beautiful appearance and softness, chenille yarn has become the choice of
fabric designers for many items. The softness and sheen of chenille improves the
appearance and hand of thousands of everyday items, including sweaters,
outerwear fabrics, upholstery and curtain fabrics, throws and blankets, and area
rugs. Chenille is a pile yarn that has been produced commercially since the
1970s. In the early years, the machinery used for commercial production resulted
in chenille with variable characteristics. Modern machinery was introduced in
Europe and North America in the early 1990s, and today's chenille is a reliable
and beautiful yarn that is gaining in popularity CIMA is dedicated to improving
industry manufacturing practices through education, to assure easier use of this
beautiful yarn. Chenille is a difficult yarn to manufacture, requiring great
care in production. Due to the nature of chenille's pile direction, pile
completeness (or lack of missing pile), and strength-to-bulk relationship, great
care must be taken in converting chenille into final articles. The following
information is designed to give an understanding of the chenille manufacturing
process and the technical specifications necessary to properly convert chenille
yarn into finished goods.
The Nature of Chenille
Chenille yarn consists of short lengths of spun yarn or filament that are held
together by two ends of highly twisted fine strong yarn. The short lengths are
called the pile and the highly twisted yarns are called the core. Chenille yarn
can be made from many different types of fibers and yarns. Most common are
cotton, viscose (rayon), acrylic, and polypropylene (olefin). Chenille yarn can
be made in many different sizes, ranging from as heavy as Nm 0.2 to as fine as
Nm 12.0.
The Manufacturing Process
Chenille yarn is manufactured on a machine that is designed to bring the pile
yarns and core yarns together. During manufacture, the pile yarns are wrapped
around a short stem of polished metal, called a caliper, through which a blade
passes to cut the pile yarns into short lengths. The core yarns are pressed onto
the short lengths with a rotating metal wheel. The resulting yarn is then fed
onto a traditional ring twisting take up mechanism. In the twisting process, the
two ends of core yarn twist and trap the short ends of pile between the core
yarns. The size of the caliper determines the diameter of the resulting yarn.
The size and number of the pile yarns and how much of them are fed onto the core
determines the count of the yarn.
Chenille Quality Tolerances
The nature of the chenille process results in a wider range of yield and twist
variation compared to other yarn manufacturing processes. The yield and twist
tolerances are as follows:
International Specification for Chenille Count and Twist Tolerances
| Sample Size | 1 | 5 | 10 | 25 | 100 |
| Count/Yield (% ") | 20.0 | 10.0 | 6.0 | 4.0 | 2.0 |
| Twist (% ") | 20.0 | 10.0 | 6.0 | 4.0 | 2.0 |
This is a new standard. For count/yield testing, these tolerances are based on a 25-meter sample length measured using standard practices for tension control in regulated temperature and humidity conditions. For twist, the tolerances are based on a standard twist tester in regulated temperature and humidity conditions.
Chenille Yarn Manufacture
Chenille is manufactured in a two step process. Step one is the manufacture of
the chenille onto a chenille bobbin, and step two is the rewinding of the
chenille onto a cone or dye tube. An electronic clearer is located in the yarn
path of step two to detect lengths of yarn that have pile missing. When the
electronic clearer detects a section of missing pile greater than the minimum
setting specified (usually 3 mm), a cutter is electronically activated. The yarn
is cut, and the winder operator then pulls the yarn back and cuts out the
missing pile section, reties the yarn, and continues winding the package.
package. The electronic clearer devices are almost 100% effective.
Electronic Clearing of Missing
Pile
It is important to verify with your chenille supplier that the chenille yarn has
been electronically cleared to remove the missing pile
Knots and Splices
Knotting or splicing chenille must be done carefully to avoid defects in the
items that use chenille yarn. Simply tying a knot in the chenille yarn itself
creates such a defect so there are two alternative methods for "tying"
the chenille yarn. Method one is a core knot. This is made by stripping back the
pile of both ends of the chenille sufficiently so that it is possible to tie a
double square knot in the core yarns. Care has to be taken to hold the twist in
the yarn ends where the pile starts. Once the double square knot is tied, the
ends are clipped close to the small knot. The pile ends are then pushed over the
knot. Method two uses a splice. To create the splice, the two ends of chenille
are overlapped 1 to 2 inches and a mechanical wrap-around splicing device
applies the wrap yarn. The wrap yarn can be either a fine monofilament nylon or
a very fine yarn of the same fiber as the chenille pile.
Pile Direction
The chenille manufacturing process creates pile that lies in one direction. When
woven into a fabric, chenille reflects light differently when viewed from
different directions. This is known as the "reflection effect," and it
is one of the unique and desirable characteristics of chenille goods. Because of
this, strict control of the pile direction must be maintained during both the
step of manufacturing the chenille and also all subsequent processes required to
convert the chenille into a finished article. Following step one of
manufacturing, the yarn has direction one. After the winding process in step
two, the yarn has direction two. The chenille yarn producer has taken all the
necessary steps to ensure that the chenille yarn is all in the same direction
when it is shipped to the user. The chenille yarn user must take care to
maintain the same pile direction throughout manufacturing. For example, with
yarn sold on dye tubes and coned aft dying, if rewinding is necessary (as in the
case of cross-wound yarn or packages that are too hard or soft), the yarn must
be rewound TWICE so that all the yarn remains in the original pile direction. If
this rule is not strictly observed, streaks will result in the final fabric.
Fiber Composition
Fiber composition is quoted on the chenille yarn supplier's invoice and on the
yarn cone. If the yarn is put up on a dye carrier, labels are not used on the
yarn carrier to avoid possible interference during the dyeing process. NOTE: In
Europe the term is dye carrier, in the America's, the term used is dye tube.
Using Chenille
The following information is designed as a basic technical guideline for converting chenille yarn in weaving and knitting mills and dyehouses. Further information can be obtained by contacting CIMA.
- In the Weaving Mill
Because of its comparatively coarse Nm-count, chenille is best processed on a rapier/ gripper projectile loom. Specifically, a Dornier-rapier loom produces the most favorable results. In most cases chenille yarn is woven together with a plain fine yarn in the filling weft, and difficulties in weft insertion can occur when the rapier has to change from picking up the chenille yarn to the finer plain yarn. The Dornier loom's rapier is the most capable of being adjusted to pick up both heavy and fine yarn. Regardless of the type of machinery used, certain guidelines must be followed for processing chenille.
Feed from Cross-Wound Packages
The chenille manufacturing process creates minor variations in count and twist, within admissible tolerances. This can have a negative effect on the structure of the cloth when working single-shuttle or from one package on a rapier loom. One should always work multi-shuttle or multiple feed on a rapier loom in order to avoid the appearance of stripes or other flaws in the final material. The best results are from three or four randomly selected feeds. When producing a completely plain fabric it is also advisable to start with the three or four packages with different diameters to guarantee uniform cloth quality. If the feeding packages have identical diameters, the take-off tension of the chenille yarn increases as the package diameter decreases, making the cloth progressively more tight and changing its appearance.
Use of Different Yarn Carriers
The type of yarn carrier used will depend upon the dyeing process used for the chenille.
For Dyeing in Europe
If the chenille is to be processed already dyed, it should be ordered on dye cones. If large package units are desired for feeding, a cone with a 10 inch traverse and a core ity of 2' 30' is appropriate. It should be taken into account whether these dimensions the space available at the creel and whether they are suitable for the dyehouse. A cone with a six inch traverse and a conicity of 4" 20' can also be used, but this con presents certain disadvantages. One disadvantage is a considerably shorter running length compared to the 10" cone. The other disadvantage is that the 6" cone can cause double threads and irregularities to be woven into the fabric. This is caused by the relationship of the package to the core diameter. With a 6" cone, more windings occur per unit of length, in addition to t normal twist of the yarn. The additional windings can occur so far from the brake that the spring force of the brake is overcome and the yarn accumulating in the direction the package is drawn into the material, along with the additional windings and crinklings. These irregularities would then have to be eliminated or corrected in the later inspection process. Using 10" cones will reduce the chance of these irregularities, because of the improve package-to-core diameter relationship.
For Dyeing in the USA
USA dyehouses dye on dye tubes. The type of dye tube used by your dyer should be specified to the chenille yarn supplier. After dyeing, the dyer will then wind the yarn onto a cone. If the finished goods are to be piece-dyed, it is best to use 10" 30 30' cones. This will result in a package with a weight of 2.5 to 3.0 kg, and 30 mm in diameter, depending on the winding density. If the available space does not permit these large cones, then a 6" 40 20' cone can be used.
Weft or Filling Insertion
An important requirement for flawless quality is the use of thread accumulators. This helps reduce the disadvantages of using a 6" cone but is very beneficial for all sizes of cones. The desired characteristic of chenille fabric includes intended "regular irregularities." This requires a nearly tension-free weft or filling insertion or a weft or filling insertion with uniform thread tension. This is achieved with thread regulating devices. Differences in tension in the weft or filling insertion generally have a negative effect on the appearance of the goods. Because of the relatively high weaving speeds used today, the shed forming devices move so rapidly that there is hardly enough time to insert the thread properly into the shed. It is vital that the chenille yarn is inserted freely in order to obtain the desired chenille character, with its regular irregularities over the entire cloth.
- Direction of movement of Chenille Yarns
Ending lots or colors result in remnants of yarn on the cross-wound packages. When winding together remnants to make bigger units, the same pile direction of the chenille yarn must be maintained. This is accomplished by rewinding the yarn TWICE.
Changes in Lot-Numbers
When changing lot numbers, different lots must be kept absolutely separate.
- In the Knitting Mill
Chenille can be processed on warp knitting machines, weft Raschel machines, flat bed, and circular knit machines without any difficulties. The type of machine used will depend on the cloth characteristics desired and the purpose of the finished product.
Warp Knitting Machine
As with other yarns, uniform winding tension is necessary when warp beams are made. In order to avoid excessive strain on the chenille during the warping process, the thread should be supported by guiding devices that move together with the yarn. If this is not possible, then the diverting points-in the creel, for example-should be designed as guides with a larger radius. As is sometimes done with other fancy yarns, the guide bars for the chenille should be designed as guiding tubes. A relatively high tension is necessary for producing flawless quality goods; because of this, normal eyes lead to pile displacement in the chenille. Feed tension should be controlled in such a way that during the looping process the needle does not exert too much friction on the yarn. This causes displacement of the pile, which can lead to bare spots between the wales. Since the maximum thread tension is dependent on the degree of guiding, it cannot be given as a fixed value, but must be determined by suitable tests.
Weft Raschel Machine
Processing chenille on a weft Raschel entails fewer problems than on a warp knitting machine, although inexpert weft insertion can also lead to undesirable effects on the quality of the goods.
Flat Bed Knitting Machines
Chenille by its very nature has the tendency to lose its shape, every possible attention should be taken to prevent it. Knitting alternately from various packages will give to the final product a consistent appearance. In order to prevent pile loss it is advisable to knit with a tight and firm stitch. To achieve a better result in size consistency and shaping it is suggested to knit chenille together with a finer support yarn. Jacquard styling enhances the softness, brightness and bulkiness of chenille.
Feed from Cross-Wound Packages
The recommendations for using cross-wound packages in the weaving mill (see Section 1 above) can be followed here, if the knitting machine works from several cross-wound packages at once or one after the other. Working alternately from various cross-wound packages creates favorable conditions for excellent appearance of the final goods.
Wax
All chenille yarns that are to be knitted should be specified to have a knit wax applied. If for various reasons the yarn cannot be knitted within 30 days, it should be rewaxed, and to avoid direction problems it has to be rewound twice.
Direction of movement of Chenille Yarns
As with woven fabric, pile direction must be strictly maintained (see above).
Changes in Lot-Numbers
When changing lot numbers, different lots must be kept absolutely separate. - In the Dyehouse
Piece Dying
The final quality of chenille goods is determined by adhering to the correct practices in the weaving mill or knitting mill, and by the dyeing process. The nature of chenille-the fact that its pile lies in one direction-produces different results with different dyeing processes. It should also be noted that small-scale tests of piece dyeing should be carried out prior to large scale production to ensure that the pile of the chenille yarn is not washing out. An open construction combined with a vigorous piece dyeing process will definitely result in pile loss. Beam dying results in a different surface structure than dyeing in a star dyeing machine. The type of dye process used will be determined by the desired appearance of the final chenille goods. During beam dyeing, the chenille pile does not have a chance to stand up because of the pressure exerted by the various layers of goods. The thermal treatment during dyeing then fixes the pile in its position. This reduces the desirable "reflection effect" of chenille products. The surface can be improved by treatment with a pile rotor. Dyeing on a star dyeing machine is similar to hank dyeing in its higher costs and results. During the dye process, the material is suspended and hangs freely, allowing the pile to stand up. Thermal treatment then fixes the pile in this upright position. The resulting material is soft and voluminous to touch, and the "reflection effect" is more successful than in beam dyeing.
After Piece Dyeing
Shrinkage during the dyeing process will impact the width of the final material. For instance, acrylic goods can shrink 3-5% during dyeing, depending on the structure of the fabric. If the shrinkage factor can be taken into consideration during the manufacturing process, the additional step of using a stenter can be eliminated. For goods manufactured from colored chenille, post-treatment on a stenter can improve the appearance of the material due to the thermal treatment involved.
Yarn Dyeing
In the case of dyeing on cross-wound packages, the two different cone sizes of 10" 2 30'and 6" 4 20' can be used directly, or the cone diameter can be custom-designed Tests have shown that the last step of the dye bath, which is pressed through the yarn, should be from the inner side of the package outward. This pushes t inner chenille layer out of the cone perforation and guarantees smooth unwinding of the yarn from the package. Hank dyeing is definitely the best dye process for voluminous and twisted yams, but at present used only to a limited degree for chenille. Hank dyeing is considerably more expensive than other methods, and because of the hank suspension at two points-suspension and strain-an "ironing" or "flattening" effect to the chenille pile can occur. If hank dyeing is planned, the chenille manufacturer supplies the chenille yarn on cones with a diameter up to 300 mm. Because of the relatively low demand for hank dyed chenille, chenille manufacturers do not have the necessary machines to supply yarn in hanks. However, dyehouses using hank dyeing have the necessary reeling a winding machinery.
For further technical questions, please e-mail or
fax to CIMA's office in Lugano, Switzerland:
CIMA Chenille International Manufacturers Association
Corso Elvezia 16 C.P. 4511
CH-6904 Lugano (Switzerland)
Tel/Fax: 011 41 91 921 09 91
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