Higher quality yarn improves the weaving
process. Introduction of very small non-film forming resin particles in
conventional size formulations modify and provide improved fiber cohesion in
the warp yarn bundle. This transient effect provides a more compact and
improved yarn substrate to host conventional warp size polymers on the yarn
surface. Evaluation of this technology in producing mills has provided positive
results in all factors associated in the weaving process.
In the early 1800s, the introduction of the
mechanical loom promised the potential of dramatically improved fabric
production. However, the mechanical loom also introduced a level of abrasion on
warp yarn that prevented this productivity potential. The abrasion problem was
soon attacked by borrowing technology developed by the coatings industry. In
coatings, surface protection was provided by the application of natural oils
which crosslinked to form a permanent topical barrier. The concept provided the
solution, but the woven fabric was not a candidate for a permanent abrasion
barrier. Starch soon emerged as a suitable material to provide a transient
abrasion-resistant barrier to protect warp yarn. This approach soon led to the
development of the necessary machinery to apply an abrasion barrier and the
concept was adopted by the industry.
During the next two centuries, significant
improvements in coatings technology and materials have been adopted to
accommodate continual changes in yarn composition, yarn formation, and loom
technologies. Warp sizes are now
designed to meet the demands of each fabric style on a case-by-case basis. Warp size suppliers and technicians have
performed admirably in bridging continual changing technologies involved in the
journey from fiber to fabric. We now are
more secure in gauging general rules of viscosity, penetration and overall size
add-on levels for optimum weaving performance. Optimization of the sizing
formulation is now paired with the variables from the slasher through the
greige fabric.
Advances in the use of polymer/starch surface
barriers now dominate spun yarn sizing.
Abrasion protection coupled with nearly 2 centuries of experience has
achieved what is now regarded as the optimum in painting warp yarn. Unfortunately, this experience has fostered
an attitude of complacency to the potential for improving weaving performance
utilizing chemicals in the size box.
The use of nanosize resins (oligomers) has
now been evaluated as components in warp size formulations. On a theoretical basis, and the barrier
coatings approach, these materials provide little optimism for improvements in
weaving. Chemically, oligomer resins
have the basic properties of higher molecular weight polymers of the same
chemistry but are much too low in molecular weight for viable film
formation. Minor adhesion and
plasticization of conventional barrier film formers became the primary hope for
this new technology. Initial trials with
nanosize oligomers in conventional size formulations provided promising results
in both adhesion and plasticization of the barrier coating. In addition, incorporation of oligomer resins
provided differences that were not readily explained.
1.Reduction in both warp and filling stops.
2.Fiber and size shed at both the slasher and
looms were dramatically reduced.
3.Increased yardage of hard yarn on the loom
beam.
These results did not neatly fit into the
barrier concept of warp sizing.
Increased yardage on the loom beam logically indicated reduced size
pick-up on warp yarn. However, multiple
desize analysis of hard yarn from trials and normal production were
equivalent. The repetition of these
trials was consistent with the initial results.
Nanosize oligomer resins were clearly providing a mechanism to
complement barrier coating film abrasion resistance.
Microscopic (60X) photos were utilized to
determine any visual differences between standard and trial hard yarns. Yarns
containing oligomer resin in the size formulation exhibit a smoother surface
with less hard fiber disruption from the sheet break. In addition, the examination of 60X photos of
the sized yarn indicates a significant reduction in yarn core diameter. Sized
yarn diameters exhibit near 20% reduction in comparison to normal formulation
hard yarn at the same add-on.
Examination of 1040X magnification
cross-sections of yarn prior to the size box provides an explanation of the
function of nanosize resins within the yarn bundle. Vacant spaces between
fibers in the bundle are micron or greater in diameter and volume. Fibers in spun yarn systems are mildly
anionic, natural or added, which maintain a repulsive force to keep fibers
apart. As the yarn is wet-out by water,
huge numbers of millimicron oligomer resin particles penetrate and adhere to
fiber surfaces. Repulsive forces existing between fibers are overwhelmed and
the fiber surface is modified with nanosize particles. These small resin molecules provide a
like-like mutual attraction and allow fibers to be drawn closer together to
partially reduce vacant spaces within the bundle. Immediate compaction of the yarn bundle
occurs upon wet-out. A smaller yarn
substrate is now available to host the barrier film. The count of the yarn remains constant with a
smaller diameter bundle. An increase in
the density of the yarn is attributed to improved fiber cohesion within the
bundle.
For more news , please pay attention to yarn fair.
Source: JOHN LARK
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In the purchase of their apparel most women
seek primarily for “look rightness and serviceability”. For outer apparel look
– rightness is probably the first consideration. In the purchase of
underclothing and children’s wear, serviceability is commonly the first
consideration, although look – rightness is nearly always a factor, too.
Serviceability is a combination of the suitability of fabric and the quality of
garments construction. Some basic categories are hosiery, sleepwear,
undergarments, blouses.
Apparel fabrics for Women and Children
Differences in weight automatically limit
some fabrics to particular seasons and use. In summer thin fabrics, such as
voile, eyelet, batiste, sheer, creeps, and chiffons, in winter, for heavier
materials such as wood tweeds, homespuns, velvet, corduroy, and fur like
fabric.
Some stiff fabrics look better when a crisp
appearance is required; soft and clinging fabrics are appropriate when slinky,
draped effect is desired; rich and luxurious fabrics look best in the evening;
washable fabrics appear to advantage when worn in the house, in the garden, and
for sports.
Women’s Skirts
Women’s skirts are cut on straight, the bias,
or circularly from the same fabrics that are used for dresses and suits. The
fit or, more particularly the hang of skirt is important. A skirt should not
wrinkle below the waistband and should be even at hem. The principles for
selection of appropriate outer garments for adults are essentially the same for
girls. Coats and dresses must be style – right for the occasion. All girls,
especially up to 10 years, need a roomy garment with large armholes and curved
underarms, to permit raising the hands above the head without pulling out the
seams or distorting the fabric. Tucks, pleats, and shirring are important
because they allow for chest expansion.
Women’s Sweaters
The sweater, a knitted of the garment for the
upper part of the body, has long been a staple for both casual and dressy wear.
There are two main or classic types: the pullover or slip -on and the cardigan.
Either type may have long or short sleeves, or either type may be in a classic
or contemporary style.
The classic sweater, not usually bulky, has a
round neck without a collar. Contemporary styles are usually bulky and may have
cable stitch and cowl necks. Until the development of the non – cellulosic
man-made fibers, wool was the major fiber used for sweaters, with cotton an
important fiber for children’s wear. But today the acrylics, particularly Orlon
and Acrilan, are in the first place, with blends second and wool third.
The reason for the great popularity of the
synthetic is that they can be cleaned in the home laundry machine at the
setting for fine fabrics, and they need no reshaping. Wool sweaters, unless
labelled “machine washable,” have to be hand washed, reshaped, and dried most
carefully. Also, man-made fibers are usually less expensive than comparable
wool products and are better than wool in resistance to abrasion.
The degree of softness of sweaters made from
man-made fibers depends on the fiber denier (weight and fineness) the finer the
denier the softer the fabric. The acrylics provide a wool – like bulkiness by
crimping short filaments so that they resemble wool fibers.Thus they provide
more warmth than nylon. Nylon, which is crimped also but is less bulky, has a
smooth texture and a slightly shiny surface.
It is more readily distinguishable from wool
that is acrylic fiber. Acrylic fiber pills more than nylon laundering and more
particularly in rubbing against other garments or furniture. On other hands,
nylon is more easily snagged by sharp objects and fingernails. Sweaters are
also made of 100% polyester.
Blouses
The degree of softness of sweaters made from
man-made fibers depends on the fiber denier (weight and fineness) the finer the
denier the softer the fabric. The acrylics provide a wool – like bulkiness by
crimping short filaments so that they resemble wool fibers. Thus they provide
more warmth than nylon.
Nylon, which is crimped also but is less
bulky, has a smooth texture and a slightly shiny surface. It is more readily
distinguishable from wool that is acrylic fiber.
Acrylic fiber pills more than nylon
laundering and more particularly in rubbing against other garments or
furniture. On other hands, nylon is more easily snagged by sharp objects and
fingernails. Sweaters are also made of 100% polyester.
Coats and Suits
When women buy coats they look for style,
color, fabric, fit, comfort, and price. To one woman, color and style may be
most important; to another, comfort and price are paramount. And to still
another, fabric, color, and fit may be the major considerations.
The weight of outer garments is governed by
the season. Spring coats are lighter in weight than fall coats, and winter
coats, of course, are of the heaviest fabrics.
Coats of cashmere or cashmere and wool and
wool blends, camel’s hair, single and bonded cloths, poplin, faille, worsted
sharkskin, wool Shetland (single or bonded) are used in spring and fall. Suits
and pantsuits of gabardine, whipcord, tweed faille, covert, serge, corduroy,
knitted fabrics are also used in spring and fall seasons.
Coats made of fur like fabrics, wool tweed
(single and bonded), cashmere ottoman (wool/nylon bonded to cotton and other
blends), covert (wool/nylon bonded to acetate tricot), cashmere, Melton, wool
broadcloth are used in winter season. Suits and pantsuits of knitted fabric
(wool and blends), flannel, tweed boucle.
For more news , please pay attention to knitting
fair.
Source: Textile School
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Knitting Fair introduced the history and
origin of Blue Denim Jeans in the last article. Now let’s learn what is denim
fabric made of.
What is denim fabric made of?
Cotton
Denim is a material made from 100% cotton.
This is a cotton thread that is used to make a particular weave. It has warped
threads in which a weft thread is placed under. This forms the traditional
diagonal ribbing on the surface of the material.
What is bull denim?
Cotton Bull Denim is perfect for slipcovers,
upholstery, draperies, pillow covers, headboards and much more. Bull Denim
fabric is often referred to as “tough as nails” due to the strong 3×1 twill
construction. Although the fabric is extremely durable it is also amazingly
soft!
Why are jeans blue?
Blue was the chosen color for denim because
of the chemical properties of blue dye. Most dyes will permeate fabric in hot
temperatures, making the color stick. The natural indigo dye used in the first
jeans, on the other hand, would stick only to the outside of the threads,
according to Slate.
Definition of Denim fabrics
A coarse, twilled cotton fabric, often blue,
traditionally used for overalls and work clothes and now used for jeans and
casual wear.
Denim Pants or another garment made of this
fabric.
A similar but finer fabric used in draperies
and upholstery.
Denim Characteristics
Cotton Thread and Twill Weave
Denim is made from cotton, which is spun and
free of any debris
Blue Color
A distinguishing feature of denim is its blue
color
Durability: Denim is very strong and does not
snag or tear easily. It is also breathable, can be ironed at a high temperature
and creases easily. Suitable for long wear, it is quite stiff when new, but
softens with repeated washings.
Raw materials used for blue denim fabrics: To
produce good quality denim, the conditions have to be optimal regarding the
quality of all the raw materials and yarn used. For raw cotton and the carded
OE (rotor) or ring-spun yarns made from it, the quality criteria are as
follows:
Minimum staple length: 2.7 cm.
The proportion of short fibers (less than 12
mm long): under 40%.
Micronaire value: 4.0 to 4.5.
The Uster values for strength and elongation,
for the evenness CV and imperfections, must conform at least to the 25% plot.
The usual count range of denim warp yarns is
50 to 90 tex and weft yarns is 75 to 120 tex; finer yarns as fine as 25 tex in
twill or plain weave are often used in denim shirts.
Twist factor: 4.5 to 5.0 for warp yarns, 4.2
for weft yarns.
Low yarn hairiness.
Yarn strength and uniformity.
True blue denim Fabrics are made out of 100
percent cotton warp and weft yarns. Fabrics are also made of Elastic core-spun
yarns which are used as a weft yarn for textile fabrics and has gained great importance
in the last decade due to the fact that stretch and recovery, comfort fits and
flexibility properties.
The dual core-spun yarns are composed of
cotton/ filament that contributes durability and polyurethane-based elastane
that provides stretchability to the fabrics. Hereby, both filament and elastane
characteristics have a great influence on denim performance at the same time.
The main purpose of using this type of yarns is to achieve the effect of
filament fineness and elastane draft on denim fabric performance such as
braking force, breaking elongation, tear force, vertical elastic recovery,
moisture management that is wicking rate and water absorption properties.
Meanwhile, filament core-spun yarns with
different filament fineness and 100% cotton yarn are also used as the weft of
the denim. It is found that that filament fineness and elastane draft had a
statistically significant effect on all inspected performances of denim fabrics
except water absorption.
Polyester blends are also manufactured and
are available, however, the overwhelming majority of jeans sold are 100 percent
cotton. The most common dye used is synthetic indigo.
What dye is used for denim?
Indigo
The primary use for indigo is as a dye for
cotton yarn, which is mainly for the production of denim cloth for blue jeans.
Why do jeans fade?
As an example, blue jeans fade where the
fabric is physically rubbed. Most other natural dyes fade equally in sunlight,
and minimally when rubbed. Indigo does not form a chemical bond with the fabric,
like other dyes. The reduced state is also necessary because indigo cannot
dissolve in water, it is insoluble.
Unique Structure of Indigo dye
Indigo, or wood indigo, is a unique dye. The
extraction process reflects the different molecular characteristics of indigo,
as compared to other natural dyes. As an example, blue jeans fade where the
fabric is physically rubbed. Most other natural dyes fade equally in sunlight,
and minimally when rubbed.
Indigo does not form a chemical bond with the
fabric, like other dyes. Instead, it forms a physical bond, bonding molecularly
to the fabric when reduced. The reduced state is also necessary because indigo
cannot dissolve in water, it is insoluble.
When the indigo molecules bond to the fabric and it is re-vetted, the
indigo forms layers – like bricks. This makes indigo very impervious to
sunlight, but indigo will fade with rubbing.
Source:
Ashok Hakoo
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