This document provides a guide to improving cotton knit products by making informed decisions at each stage of manufacturing. It discusses fiber selection, yarn spinning systems, fabric construction, preparation, dyeing, and finishing processes. The quality of the final garment is directly affected by these decisions. Understanding how each step influences subsequent stages can help reduce costs, deliver higher quality products with fewer returns, and develop value-added products. The guide analyzes options at each stage and their effects on time, cost, and fabric characteristics. Consultation with experts is recommended to tailor the process to specific needs.

1. How to the ect 100% Knit
Create P erf Cotton
A Technical Guide to Improving Your Knit Products
PRODUCE FIRST QUALITY KNITS
REDUCE SURFACE FUZZING
100
Cot % INCREASE COLOR RETENTION
ton
CONTROL SHRINKAGE

2. About 60% of all garments sold at retail in the United States are knit products. In order to engineer the performance
right
your customers expect in a knit garment at the price they are willing to pay, it is important to make the
decisions about each stage of the manufacturing process. Today’s customers have myriad choices in
apparel, so they often show little brand loyalty, and if a purchase fails to meet their expectations , they are
often willing to try something different.
The consumer’s garment care practices can significantly affect the overall appearance and performance
of a cotton knit garment. Improper care results in disruption of the fabric surface, causing the garment to lose its
new appearance and to wear out prematurely. If a knit product has a tendency to fuzz easily or lose
its color quickly, this only makes the problem worse.
Consumers average 5 loads of
laundry per week and expect
to wash a dark garment 15
times before it fades.

3. n
1 00%Cotto
How to Create the Perfect Knit
A Technical Guide to Improving Your Knit Products
For over 25 years, Cotton Incorporated has conducted research examining the various cotton knit manufacturing processes and their effects on the
performance and overall quality of the resulting consumer products. The quality of the final product is directly affected by decisions made about the
manufacturing process with respect to fiber selection, yarn spinning systems, fabric construction, fabric preparation, and dyeing and finishing. Decisions
about any of these manufacturing steps can give rise to problems downstream that may not be easily remedied, resulting in a less-than-optimal product.
Such problems can be anticipated and prevented if you make well-informed decisions to engineer a product that meets both the retailer’s performance
specifications and price point and the consumer’s expectation of quality. Savvy choices will result in a product that is a good value and performs well in
terms of color retention, fabric appearance, and shrinkage. Armed with knowledge of the various manufacturing operations and how each step affects
the next, your company can make better-informed decisions that will help you
• save time and money at each manufacturing stage, by reducing costly
mistakes and off-quality goods,
• deliver a higher-quality product, resulting in fewer customer returns and greater
consumer satisfaction, and
• develop value-added products that garner higher margins.

4. Type of Product
Decision Chart for Production of Knit Garments
Being Made?
Fiber Yarn Murata Vortex
Carding Drawing
Selection Quality? Spinning
Combing Open End
Pique
Spinning
Type of
Fabric to be Product
Interlock
Roving Knit? Color?
Compact Ring
Spinning
Jersey
Conventional
Ring Spinning Scour Bleach
Cost?
Fabric Characteristics?
Performance?
Understanding the interactions between manufacturing stages, the influence of one step on another, and
the trade-offs that can be made will increase both the profitability and quality of your knit products. Bio-Polish No Bio-Polish
Cost?
This guide will walk you through the manufacturing process, step by step. Each important decision, from
Fabric Characteristics?
choice of spinning system to dye selection to choice of finishing process(es), will be addressed in terms Performance?
of the effect it has not only on the final product, but also on downstream manufacturing steps.
Vats Reactives Directs
Cotton Incorporated offers unmatched industry knowledge and expertise, based on decades of
experience and a comprehensive understanding of every step of the knit manufacturing process. The
information presented here provides a head start to creating a high-quality knit garment. However, to Cost?
Fabric Characteristics?
truly create the perfect 100% cotton knit for your company’s purposes, please consult one of our experts
Performance?
in any of the fields addressed in this guide. Our experts will discuss with you the particulars of your
manufacturing process and tailor the answers to meet your specific needs.
Chemical Mechanical
Finishing Finishing

5. Throughout this manual four different symbols will be used to indicate probable outcomes for
options at each step.
Key Learnings from this Guide:
Below are the definitions and parameters of each symbols.
 The yarn spinning system can have
a direct effect on fuzzing during home
Processing Time: Processes with this symbol will require additional manufacturing time.
laundering, though it has little effect
on color performance itself.
$ Cost: Processes with this symbol will require additional expense.  Bio-polishing is an option to control
fabric fuzzing
Hand of final knit garment: Processes with this symbol create a favorable hand to the end  Surface fuzz on knit fabrics can create
product. the appearance of color loss.
+/-
Fabric Appearance after Consumer Laundering: A plus (+) denotes positive appearance  Colorfastness is significantly affected
characteristics (less fuzzing and pilling, greater color retention) while a minus (-) indicates by dye selection, as well as consumer
the fabric will show greater amounts of pilling and fuzzing, and less apparent color care, including detergent selection.
retention. See photo below
 Selection of dyestuffs is a critical
+
step; reactive dyes maintain their color
strength and shade better than direct
or sulfur dyes.
 Resin finishing is an alternative to
bio-polishing for control of fabric
fuzzing.
A visual fuzzing scale used to numerically rate
 Softener selection influences surface
appearance and color retention.
 The overall sequence of
manufacturing processes can affect
fabrics after laundering
color performance.
 Consumer care practices can affect
fabric surface appearance
-
It is important to note the above symbols are assigned to each alternative in relation to other options at that particular point in the
manufacturing process, and are meant to be used strictly as a guideline in making decisions. The actual amount of increased time
or cost will depend on the specific manufacturer.

6. Fiber Processing
and Yarn Spinning
Cotton fiber properties directly affect a knit garment’s quality, appearance, and
performance. It is important to select cotton fiber with the appropriate properties for
each specific end product. It also is important to choose the appropriate spinning system
to produce cotton yarn that will yield the desired fabric characteristics. The three current
spinning systems have different effects on the yarn structure and therefore on the final
product. Sourcing companies must determine which combination of fiber and spinning
system will result in a knit product with the desired key characteristics. Decisions made
about yarn spinning will affect appearance, softness (which depends on yarn hairiness and
twist), color retention, yarn strength for performance, and cost factors related to spinning.

7. Ring Spinning Open End Spinning Vortex Spinning
(Conventional & Compact)
$$$ $ $$
Courtesy of Sussa
Courtesy of Murata
Conventional spun yarn
Courtesy of M.J. Grimson
shown on the left, compact
spun yarn on the right in
Courtesy of M.J. Grimson
both photos
Conventional ring spinning is the oldest production
method used today, yet incorporates many of the
Open-end rotor spinning has a production rate up
latest technologies. It is also the most expensive and
to ten times that of ring spinning. Open-end rotor
time-intensive system, because of the roving step at
spinning begins with sliver fed into a combing or Vortex spinning, a form of air-jet spinning, has the
the beginning and the winding step at the end. This
opening roller. This process separates the sliver highest production rate of all the spinning systems.
system allows for the largest range of yarn counts
into individual fibers, which are transferred into a It begins with sliver fed into a high-speed roller
and is capable of spinning especially fine counts.
rapidly spinning rotor where the sliver meets the and apron drafting system. An air vortex imparts
Compact ring spinning differs from conventional
tail of the feeder yarn. Twist is inserted into the twist to the leading fibers as the fibers leave the
ring spinning by using suction in the bottom roller
exposed yarn end. The yarn package is ready to front roller; the air wraps the leading fibers around
to control the fiber in a more uniform manner. As a
be used right off the machine. Open-end spinning the core fibers. Yarn packages are ready to use
result, the fibers are more tightly condensed when
produces a smaller range of yarn counts than ring right off the machine.
exiting the front roller. (See the photo above right.)
spinning.
Yarn Characteristics Note: Ring spinning is used as a benchmark for comparison of spinning systems
Conventional Compact Open End Vortex
Ring Spinning Ring Spinning Spinning Spinning
Strength Lower cost High production rate
Strength
Flexible yarn count High production rate Yarn evenness
Low yarn hariness
S and Z twist yarns Lowest yarn hariness Resistance to abrasion
Less bulky yarn
High yarn hariness Yarn evenness Strength
Less soft fabric hand
Fabric fuzzing Limited yarn counts Low yarn hariness
Low production rate
Soft fabric hand Less soft fabric hand Less soft fabric hand
High cost Strength Critical system to
Low production rate Z twist only operate

8. Proper fabric construction is essential to creating a well-
engineered garment. Fabric construction must be engineered
from the start of the manufacturing process, through selection
of the right fiber, the appropriate yarn for the specific knitting
machine, and the right stitch length. At the next step of the
process, dyeing and finishing can either improve or impair the
Fabric performance of any given fabric construction. To produce a
knit fabric that delivers the best performance at the desired
Construction
cost, well-engineered construction must be combined with the
appropriate dyeing and finishing processes. A knitting mill should
have knowledgeable staff who can engineer the fabric to the
performance specifications provided by the customer.

9. Engineering Cotton Knits
Cotton knit products must be engineered for performance. This means they must be planned, constructed, and managed correctly at each step of the knitting process. Many factors
relate directly to the performance of cotton knits, including fiber selection, yarn type and knitting parameters. The most critical considerations in engineering a cotton knit are the con-
struction variables and the length processing tensions.
Construction variables:
Factors relating to construction include fiber type, yarn type, machine gauge and diameter, stitch length, and type of stitch. This section focuses on the elements that are selected and
controlled by the knitter.
Yarn:
Four main factors determine a yarn’s performance: size, type, twist multiple, and twist direction. The size of cotton yarn relates to its yield, width, and performance. Yarn size usually is
measured by a cotton count system, which is an indirect numbering system; by the English cotton count system (Ne), the higher the yarn number, the smaller the yarn. Yarn type captures
the spinning process used, how the yarn was assembled (e.g., single or plied), and whether it is a spun yarn or a filament yarn. Finally, yarn type and twist determine the hand, appearance,
and strength of the fabric, and they are the main factors affecting skew or torque.
TURNS PER INCH The shorter the stitch length: The longer the stitch length:
TM (Twist Multiple) =
√NE the less yarn in a stitch the more yarn in a stitch
Machine Gauge: the tighter the stitch the looser the stitch
The machine gauge or cut is determined by the number of needles and the diameter of the machine. When the less the length shrinkage the more the length shrinkage
selecting a machine gauge, you are also selecting a range of yarn sizes. Only certain yarn counts can be used the more the width shrinkage the more the width shrinkage
on each type of knitting machine, and this factor determines the types of knit products that can be produced the narrower the fabric the wider the fabric
from a given machine. Generally, the higher the machine gauge, the finer the yarns that can be knitted. the heavier the fabric the lighter the fabric
the firmer the hand the softer the hand
Stitch Length:
Stitch length is the amount of yarn in one stitch repeat, and course length refers to the amount of yarn used
in one revolution of the knitting machine. Stitch length affects the weight, width, and shrinkage of the fabric.
If the stitch is too short, excessive stress on the yarn and knitting elements can result in holes. If the stitch is too long, dropped stitches are
more likely. It is important to determine the proper stitch length for the desired fabric properties. As shown in the chart to the right, short
and long stitches affect the fabric’s performance in very different ways.
A measurement related to stitch length is the tightness factor, a number that indicates the relative tightness of knitting, taking into
account both the thickness of the yarn and the length of the loops. The tightness factor is important because when this number is out of
range, the machine can operate at lower efficiency and produce a fabric with defects or a harsher hand. In addition, knitting costs can be
higher, because higher-quality yarn is needed than for the same type of fabric knit with a lower tightness factor.
English Metric Suggested Tightness Factor Ranges
9.567 √TEX
TF (Tightness Factor) = Normal Limits
L in √NE L cm
Single 14-18 12-20
Type of stitch: Interlock 10-14 8-16
Three basic stitches are available to a knitter: jersey, tuck, and float.These three stitches 1X1 Rib 14-18 12-20
are combined to create a multitude of design and performance characteristics in Single Pique 14-18 12-20
knit fabrics. Illustrations of these stitches can be seen to the far right. Six-Thread Pique 14-18 12-20

10. Controlling Shrinkage

11. Controlling Shrinkage
In today’s competitive markets, where high quality is expected at a low price, apparel companies are demanding low shrinkage. Furthermore, shrinkage must be consistent from garment
to garment in the same style and fabric construction. The term “shrinkage” is commonly used to mean any dimensional change in a fabric or garment - either shrinkage or growth - caused
by the application of force or a change in environment. For a cotton garment, shrinkage characteristics affect parameters such as seam puckering, torquing, and overall garment fit.
Shrinkage during the manufacturing process is caused by two types of factors: those relating to the construction of the fabric or garment and those relating to how the fabric or garment
is processed.
Construction Shrinkage:
Dimensional changes during construction occur as a result of such parameters as fiber, yarn, machine gauge, total number of needles, stitch or course length, and type of stitch. This type
of shrinkage is controlled by careful selection of construction parameters to meet fabric specifications.
Processing Shrinkage:
Dimensional changes during processing can occur during any dyeing or finishing step (whether chemical or mechanical) and usually affect both the length and width of the fabric. Keys
to reducing shrinkage and improving fabric performance are processing the fabric with minimal tension and using compacting or relaxed drying steps.
Various wet processing techniques have different effects on shrinkage. In general,
batch processing (in a jet dyeing machine) applies less linear tension on the fabric
than continuous processing. Processes such as napping, sanding, and merceriza-
tion apply high tension, while others such as relaxed drying apply low tension.
Weft knits can be processed either open width or in tubular form. Each process
applies tension in different ways, and different processes used on the same greige
and dyed fabric will result in different performance. Resin treatment also has a
Width stretched
huge effect on both fabric strength and shrinkage.
Above and right are illustrations of a regular
Relaxed Drying Relaxed stitch fabric and fabrics that have been stretched.
Length stretched
and Compacting
Relaxed drying and compacting are two methods used for shrinkage control in knit fabrics. On the opposite page is a photo of a compacting machine. Below is an illustration of the
relaxed drying process and a photo of the actual drying machine.
In this illustration, fabric is fed in from the left into the dryer where it is dried with slack in the fabric
to allow it to return to its pre-engineered shape.

12. Fabric
Preparation
In the preparation stage, the greige cotton fabric is scoured
and/or bleached to remove impurities, thus increasing its
whiteness and absorbency. This step prepares the fabric
to receive dye or other wet processes. One additional step
that can be performed before dyeing, to ensure an end
product free of surface fuzz, is bio-polishing. Bio-polishing
is a cellulase enzyme treatment that removes cotton fibers
protruding from the yarn or fabric surface to create a less
hairy knit fabric with clear stitch definition. Bio-polishing is
one way to clean up the surface of a fabric made of lower-
quality yarn, but it should not be considered a cure-all for
poor-quality, excessively hairy yarn.
Courtesy of Carolina Cotton Works, Inc.
The photo to the right shows a
Jemco Bleaching machine

13. No Bio-Polish - With Bio-Polish + $
Fabrics not treated with cellulase enzymes tend to have more surface Bio-polishing can reduce fabric surface disruption on a garment
fuzzing after 20 home launderings. during home laundering. Applied correctly, it can impart an “as
new” appearance that is maintained for the life of the garment. The
However, if fabric is to be finished with a resin treatment, bio-polishing combination of bio-polishing and a resin finish was most effective in
may not be necessary, because the resin will inhibit fuzzing during home reducing shade change after multiple launderings. However, using
laundering and tumble drying. Choosing a less hairy yarn also could both bio-polishing and resin adds an extra bath, which translates to
eliminate the need for bio-polishing. extra processing time and cost.
The photos show non-enzyme treated (below) and enzyme treated
(right) knit fabrics after laundering, as well as a close up of the fibers.
How are fabrics bio-polished?
Manufacturers use a bath or series of baths to bio-polish fabrics. Depending on other factors in the manufacturing process, this step can be done before or after
dyeing. Bio-polishing parameters must be strictly controlled to avoid damage to the fabric as a result of the process. Processing time, temperature, pH, and the
amount of enzyme in the bath must all be coordinated to achieve the desired result. If these factors are not at the correct levels, the fabric may have excessive
loss of weight and strength.

14. Dye Selection
Fabric appearance and color retention are significantly affected by dye selection.
It is essential to select dyes that have the right fastness properties for the desired
end product. Within a class of dyes, quality and price can vary. Use of high-quality
dyes, from reputable suppliers, will improve fastness. It is important to understand
the different types of dyestuffs available for cotton and to understand the
trade-offs between performance and cost. Decisions made at this stage directly
affect the garment’s colorfastness when laundered by the consumer.
Another important factor is the process used to dye the fabric. Knits fabrics are
most commonly jet dyed in sealed vessels. Jet dyeing can be used with various
dye classes. In the dyeing process, it is essential to avoid excessive abrasion of the
fabric surface, which will affect the appearance of the end product.

15. Choosing a Dye
Dye selection for cotton knits is an important part of the manufacturing process. As illustrated below, each dye class has both advantages and disadvantages. It is
necessary to understand these differences in order to select the dye that is best for your product.
Shade Application Wash Light Crock
Dye Class Brightness Time Fastness Fastness Fastness
Reactive +++ +++ ++ ++
Direct ++ + +++ ++
+ +++ +++ ++
Vat
Sulfur + ++ + +
Characteristics
To achieve a quality end product, dyes should have:
 Good cold water bleed characteristics
 Good colorfastness to levels of chlorine in municipal systems
 Shading components with good performance properties
 Durability to multiple home launderings
Courtesy of Gaston County Dyeing Machine Company
Process
In jet dyeing machines, both the fabric and dye liquor are moved simultaneously. Fabric is moved through a venturi
tube, and dye is pumped through the tube as the fabric moves by. The photo to the right shows unloading of the
machine after a dyeing cycle.
Benefits of using a jet dyeing process: The greatest benefit is the versatility of being able to use the same machine
to bleach, enzyme treat, and dye. In addition, jet dyeing uses a low liquor ratio; using less water saves on energy for
heating the water and reduces the amount of waste water that must be treated and disposed of. New machines can
use a ratio of water to dye as low as 5:1.

16. Finishing
Although the finishing of a knit fabric can make or
break the final product quality, the other steps in the
manufacturing process can have just as great an effect.
In determining how to finish a product, it is essential
to understand that decisions in the manufacturing
process are cumulative. Finishing is not a cure-all,
and it cannot overcome limitations resulting from
earlier steps in the process. In fact, finishing can even
have counterproductive effects if the manufacturing
process has not been thought through all the way
to the end. Engineering of the product should start
at the end of the manufacturing process and work
backwards. Identifying and understanding the
specific properties desired in the final product will
allow you to make better-informed decisions for
each stage of the process, ensuring that the finished
product has the characteristics you intended.

17. Resin $ Finishing Options: $
Resin treatment can be used in place of bio-polishing to reduce fuzzing. Its effects The options for finishing knit products are seemingly endless. Everything
can be similar; however, resin alone does not improve the color performance of knit from water repellent to soil release to flame retardant properties can be
fabrics. Although resin can help maintain a knit fabric’s dimensional stability and control incorporated onto the fabric. In addition, surface finishes such as sanding,
shrinkage, it can also weaken the fabric. The amount of resin added to the fabric should sueding, napping, and shearing offer ways to dramatically alter the hand
be carefully determined to achieve a balance of performance and strength. or appearance of the end product. It is important to remember that all of
these processes will affect the visual characteristics of the final product,
including the color and shade. To ensure that the final product has the
Softener - $
desired properties, plans for finishing need to be taken into account when
the choices are made for every earlier step in the manufacturing process.
Some silicone softeners can make fabric more prone to fuzzing during laundering, causing
the perception of color loss. Choice of softener is key to minimizing surface fuzzing due
to repetitive laundering.
Napping Shearing Water
Repellent
To the left is an illustration and a photo of a
tenter frame. Fabric is fed through rollers (here
shown from the right) and set into a frame to
hold it in place. The fabric then enters several
ovens, where the processing occurs. Tenter
frames are used for many purposes, including
drying and curing and controlling skew.

18. Consumer Care

19. Garment Labeling
Garment care labels are an important factor in maintaining the quality and appearance of a knit garment once it leaves the store.
Understanding consumer laundry habits and how clothes are washed helps manufacturers to reduce problems resulting from
improper laundering, to prolong an “as new” appearance.
Two thirds (67%) of consumers “always” or “usually” refer to the care label before washing.
If a shirt fell apart in the laundry, only 17% of consumers would hold themselves responsible for not reading the
instructions. More than 70% would blame the manufacturer.
Simple actions by the consumer can preserve the appearance of a knit fabric and lengthen the life of a garment:
 Turn garments inside out before laundering, to reduce fabric surface abrasion.
 Use detergents with chlorine scavengers, to reduce fading due to chlorine in the water.
 Set the right water level in the washer for the amount of clothes, to reduce fabric surface abrasion.
 Prevent over drying in the tumble dryer by checking progress frequently, to reduce abrasion and shrinkage.
What Happens in the Laundry?
Why did my shirt shrink in the dryer?
Only 20% of consumers were aware that the dryer, not the hot water or the fiber type, causes shrinkage. However, many of these
consumers incorrectly identified the heat from the dryer as the reason their shirt went down a few sizes. In fact, the culprit is not the
temperature; shrinkage actually is caused by the dryer’s tumbling action.
Does abrasion happen in the washer or the dryer?
Abrasion can happen in either machine as a result of overloading. When clothes do not have enough room to move around, they
rub against each other and machine components constantly. Consumers can decrease abrasion-related fuzzing by not overloading
machines, as well as by turning garments inside out for laundering.

20. Cotton Incorporated
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