This brochure has been prepared by the members of the Chenille International
Manufacturer's Association (CIMA) and is designed to provide information
on the background, manufacture and "how-to use" guidance for chenille
yarns.
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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