A sample jigger for dyeing up to
20 meters of fabric at atmospheric conditions.
WicItt,
Min. 20 inches
Fabric fp 1 e d
Variable Speed Control
Fabric tension
Adjustable
Temperature range
Room temperature to 95 C or above
Heating
Electrical heating with rate of
rise and top temperature control
APPLICATION TECHNIQUES
The quantities to use depend mainly on the type of dyes used and on the biggest or smaller. Read about Woven Fabric Jigger Machine
contact with the air of the dye bath that loses reduction potential.
with similar redox potential , provides a lower pH than ordinary sodium
sulphur.
This inferior alkalinity offers the following advantages:
Smaller degradation of sensitive fibers in goods containing weaker fibres (half wool, rayon
acetate, etc.).
Less cellulosic fibres swelling and consequently, easy dye penetration in machines with bath
circulation through the material.
Another advantage of the in front of the sodium sulphur it is the easy
removal of the remaining sulphur by means of a single cold rinsing after the dye.
is odourless and it doesn’t produce any scent, avoiding the troubles
working with conventional sulphur reducers.
Reduction state can be checked on the way, dropping the dye bath on a filter paper, the stain
should not present insoluble particles and the extended aureole , it should be coloured the same all
over from the central part where it has thrown the drop.
We can recommend:
Dye in Jet R/b 1:10 – 1:15
2 to 4 gr. / l
Dye in Jigger R/b 1:3 – 1:6
4 to 8 gr. / l
Dye in Autoclave R/b 1:10
2 to 3 g. / l.
Information about safety properties can be found in MSDS (Material Safety Data Sheet).The right of the product and to make change in its prospect is concealed by us MKS Devo R&D laboratories can provide more info on application techniques of the product
Bias Line-Definition and Causes
This condition which can easily be seen on the greige goods
also predominantly occurs in the single Jersey structures and, if finished
incorrectly, can cause angular hem line distortion.
The main cause for this condition is knitting machine’s
feeder numbers. As a general rule increasing the number of feeders increases
the Bias angle.
With the increase in demand for finer and lighter weight
fabrics and also increase in the number of feeders in knitting machines this problem
is becoming more evident.
Due to the nature of weft circular knitting process certain
Bias is inevitable and most fabric producers and garment manufacturers have
come to learn to effectively manage this problem.
With new and advanced knitting machines, in order to
increase the rate of production, the number of feeders has been increased, thus
accentuating this angular distortion.
Preventive Suggestions
To reduce the angular distortion and have a manageable
measure of Bias, the simple remedy is to reduce the number of feeders (lower
than 92, preferably down to 60). This is done by disengaging some of the
knitting zone’s needles. Correct finishing of the fabric as well as an
adjustment in the markers to compensate for the excessive Bias are other important
steps that need to be taken.
Corrective Measures
During the dyeing process, due to exposure to water and
temperature and the subsequent shrinkage that takes place, the fabric will
obtain a dimensionally relaxed state including its natural Bias.This is the exact state in which the fabric needs to be
dried at.Any attempt to correct the natural Bias (even severe Bias),
will create an unnatural condition.
The garment manufacturers can now use this fabric provided
that they make the necessary adjustments in their markers to compensate for the
Bias.
We know carpet is a colorful
thing. It is mainly used for floor coverings. It is increases the beauty of
home and official also.
Objective of Dyed yarn sorting:
To makes separate bundle of yarn according to
cloth.
To helpful for knotting.
Winch Dyeing MachineProcedure:
After dyeing and drying the yarn.
Then it is sorting into a beam.
It is sorting by hand.
Washing and Wash Rug Drying:
After knotting a full carpet
actually made. Then it is needs to be wash. After wash it will be ready for
next process.
Objective of Washing and Wash Rug Drying:
To remove impurities is from carpet.
To increase lusture of carpet.
To make soft handle.
Procedure:
First we haveto lay the carpet in the field.
Then it is have to fall water on the surface of carpet.
Then wash the carpet by brush.
Then have to dry the carpet by sunlight.
Dyeing Related Defects/Problems
Uneven Appearance and Blotchiness-
Definition and Causes:
There are many factors that could cause these conditions.
The following are the most common causes:
uneven exhaustion of dyes (disperse and acid dyes)
uneven absorption of dyes
(reactive and direct dyes)
incompatibility of dyes in the color formula
incorrect or incomplete preparation of the greige goods
prior to dyeing
left-over and un-removed preparation chemicals prior to
dyeing (Hydrogen Peroxide)
insufficient and improper use of Retarders/Leveling
chemicals (in direct dyes)
incorrect fabric dwell time in the dye machine
high dye bath water hardness
application of fixing chemicals in un-clean dye bath water
the use of high energy disperse dyes at low temperatures etc.
Preventive Suggestions:
Due to the complexity of the dyeing process, every technical
aspect of dyes, chemicals and type of machineries, must be studied and taken in
to consideration before any attempt is made to select a procedure to dye a
fabric.
Corrective Measures:
Generally, and in less severe cases, removal and stripping
the original color and re-dyeing the fabric may correct the problem. Although,
total removal of the original color may weaken the fabric and thus special care
is required.
In more severe cases, over-dyeing in to a darker shade or
black may be the only solution.
Non-Union Dyeing (Cross-Dyeing)-
Definition and Causes:
This is a common problem with fabrics that are made with
blended yarns where one component of the yarn appears to be of a different shade.
Preventive Suggestions:
In order to get an even and uniform (union) color, both
fibers need to be dyed to the same color according to their percentage content.
This could be done by dyeing one component first followed by
the other fiber. This is known as “2 bath dyeing “
The other way would be to dye both components
simultaneously, which is referred to as
“1 bath dyeing”. This process is difficult and can not be
performed for certain colors.
In either case care must be taken to ensure that complete dye
uniformity is achieved.
Corrective Measures:
In most cases the non-union color can be corrected by making
an appropriate dye addition.
Winch Dyeing Machine : It is, however, very important to make sure any softeners or other finishing chemicals that are on the fabric are thoroughly removed before the dye addition is made.
Softflow Dyeing Machine – Woven and knit goods of various kind
Processing capacity: Weaight:
Min. 1 Kg or above
Cloth Speed:
Variable Speed Control
Liquir Volume:
10 – 60 Liters or higher
Max-working Temperature:
130 C or higher
Material of Machine:
Stainless steel
Heating/ Cooling
Heating at Below 0.5 to above 4
°C/min and cooling below 3 °C/min
Liquor preparation bath
Min. 10 L
Liquor preparation bath
Min. 10 L
Dye Spots-
Definition and Causes:
This common problem and defect can be caused by one or a
combination of the following:
Undessolved dyes, especially if dye granules and powder instead of liquid dyes are used. Read about Woven Fabric Jigger Machine
Incorrect use of Defoamer chemicals. In certain dye
procedures due to the machine’s high pressure and temperature, the interaction
of some chemicals produces a large volume of foam which can inhibit the
fabric’s rotation and movement. To remove this, de-foaming chemicals are used.
Incomplete removal of these foams can sometimes cause a build-up of coagulated
small particles on the fabric.
Incorrect use of Carriers in Polyester dyeing. Generally
Carrier type chemicals are used to facilitate the Disperse dye exhaustion in to
the fibers. At certain low temperatures, due to the condensation, unwashed
droplets of these chemicals can cause spots on the fabric. (Normally lighter
than the ground color).
There are other causes that could create dye spots. The above
mentioned are the most common in the industry.
Softflow Dyeing Machine Preventive Suggestions:
The use of correct procedures and chemically compatible dyes
and chemicals is a critical part of the dyeing process.
Corrective Measures:
Depending on the type of fabric, in most cases, a high
temperature scouring using
Dispersing chemicals, Phosphoric acid, and soda ash will remove the spots.
Poor Crocking-
Definition and Causes:
The transfer of dyes from one fabric surface and causing the
staining of another fabric surface through rubbing action is referred to as
Crocking and is evaluated using a standard Grey Scale system.
This is often caused by the incomplete removal and cleaning
of the left-over dyes from the fabric surface in the after-treatment process.
In the majority of dyeing processes, most of the dyes are
either fully absorbed or exhausted by the fabric (with the exception of pigment
dyeing). The left-over dyes need to be removed thoroughly.
Preventive Suggestions:
A complete after-treatment in the form of Reduction Clear
(for Disperse dyes), Fixation (for Direct and Acid dyes), and Soaping (for
Reactive dyes) must be given to minimize the staining problem.
Corrective Measures:
In most cases, repeating this after-treatment will improve
the crocking properties of the fabric.
Poor Color Fastness-
Definition and Causes:
Generally, the ability of a dyed fabric to retain its color
is referred to as Color Fastness.
This ability is normally measured in terms of fading due to
exposure to washing, perspiration, light sources, etc.
Color Fastness properties of fabrics which are also
evaluated by the Grey Scale system are adversely affected by the following:
Incomplete color fixing in direct dyeing process, reducing
the wash fastness.
Incomplete fabric soaping in Reactive dyeing, reducing the
wash fastness.
The use of Alkali sensitive dyes, reducing the perspiration
fastness.
The use of UV sensitive dyes or incorrect PH values,
reducing light fastness.
The use of dyestuffs which have poor overall fastness
properties.
There are other factors which can adversely affect dyed
fabrics color fastness. The above mentioned are the most common causes.
Preventive Suggestions:
To ensure a higher level of color fastness is achieved, all
technical aspects of dye and procedure selection must be examined and considered.
Corrective Measures – Softflow Dyeing Machine:
Based on the type of dyes used, the use of an appropriate
rewash will improve the required fastness.
Pad Steam Dyeing Machine -Plato rage 60% to 100% FabrSTheed Variable Speed Control Dwelltime in steamer Dwell time Min. 20 Sec or lower – Max. 90 seconds or higher Pad Pneumatically-Controlled, Maximum pressure 1-6kg/cm or above, NBR rubber with 70o Shore Steami amber Insulated, Max. Temperature Max 100°C or higher., Pressure 0.5mPa or above Display Digital display temperature indicator Steam Generation External Steam Generator Included Display Digital display of parameters Width Min 500 mm or above
Washing compartments Min. 4, with direct steam heating and temperature regulator Fabric take up/ batching system included Parts to be included: IR pre dryer, Steaming chamber, Steam generator
Localized Holes-
Definition Pad Steam Dyeing Machine:
The chemical reaction between the knitting oils ( see section 2 I ), left on the fabric and the Hydrogen Peroxide which is used in the preparation stage of dyeing, at higher PH levels of 7 to 13, results in the weakening of the fibers in the oil stained areas. Read about Woven Fabric Jigger Machine
This weakening of the fibers will eventually, during the
course of the dyeing process, cause localized and sporadic holes to appear.
Preventive Suggestions:
The use of water soluble knitting oils is strongly
recommended.
Yarn lubricants, especially with open-end yarns, need to be
checked to make sure the non-silicone types are used.
Corrective Measures:
For this problem no corrective measures are available.
Spandex Decomposition-
Definition and Causes:
The use of strong alkali in the preparation stage of the
dyeing process and in Reactive dyeing systems where PH values of up to 13 are
required is the main cause of the weakening, loss of elasticity and eventual
breakage of Spandex yarns.
Preventive Suggestions:
When dealing with Spandex yarns, specifically the bare
(uncovered) types and at finer counts, the use of strong alkali solutions must,
to the extent possible, be avoided.
Corrective Measures:
For this problem no corrective measures are available.
Caustic Burns-
Definition and Causes:
This is caused by the sudden exposure of areas of the fabric
to undiluted Sodium Hydroxide (caustic soda) during the dye process.
Here, due to the process of the partial “caustisization”
that takes place, these areas, after dyeing, appear on the fabric as color
intensified blotches.
Preventive Suggestions:
using a “dosing” system of delivery. Using this system, regulated and small pre-determined amounts of chemicals, at pre-determined rates, can be delivered to the dye machine.
This will prevent any possibility of fabric damage.
Corrective Measures:
For this problem no corrective measures are available.
Crease and Rope Marks-
Definition and Causes:
With medium and heavy weight fabrics, dyed in Jiggers or
continuous dyeing range, the incomplete flattening and smoothing-out of greige
goods’ wrinkles are the main causes of these problems.
With knit and light weight woven fabrics, dyed in the Jet
dyeing systems, the main causes are as follows:
fabric tangle,
machine stoppage, especially at high temperatures,
over-loading the dye machine,
lack of correct lubricants (Fiber to Fiber and Fiber to
Metal types need to be used)
incorrect fabric rotation speed
There are other causes but these are the most common ones.
Preventive Suggestions:
The use of correct dyeing process, considering all the
technical aspects is essential.
Corrective Measures:
Generally, re-dyeing the fabric at higher temperatures and
additional use of lubricants can remove the crease and rope lines.
For severe cases no corrective measures are available.
Metamerism-
Definition and Causes:
Metamerism is basically where the intensity and cast of a
color appear to vary under different light sources.
This is, usually, due to the use of incompatible dyestuffs
in creating a dye formula.
It could also be due to the presence of small particles of
optical brighteners in the fibers.
Preventive Suggestions:
Correct dye selection is a critical factor in reducing this
effect.
Corrective Measures – Pad Steam Dyeing Machine:
For this problem no corrective measures are available.
As the reduced indigo dyeing machine has very little affinity for cotton in spite of the deep shades while dyeing with concentrated vat dye, the result is sufficient fastness. For this reason the cotton warps for Blue Jeans are dyed in 4-6 passages in sheet form. By a passage it means the run of goods through an immersion, vat following by squeezing and an air passage for oxidation of dye stuff . A major part already oxidized dye stuff remains fixed to the material while being processed in the following immersion vat. Only the chemical solution is almost completely replaced by fresh indigo vat. Thus with every subsequent passage the depth of dye penetration increases. After the last air passage the stuff ringed by 2 or 3 ringed trough.
Details in Dyeing & Sizing machine:
Machine Name : Slasher Indigo Dyeing Machine.
Country of origin : West Point, USA.
Model No. : 654
No. of Machine : 01
Creel capacity : 21
Speed of the Machine : 16 meters / minute for Dark Indigo,
: 20 meters / minute for S. Black.
: 23 meters / minute for Normal Indigo.
Production capacity per day : (21x1320x.95) = 26334 Mts (Considering the product mix 65% Indigo 20% Dark Indigo,15% Sulphur Black.)
Dyes and Chemicals wastage : 1 – 2 %
Szing material wastage : 2.5%
Pls note : This yarn wastage is already taken in fabric process loss.
Down Time :
If dyeing route is similar then down time 45 minutes/Dyeing Lot. (Two and Half lot per day)
If dyeing route is different then down time 3 hours (Two time per 7 days)
If dyeing route is same but need to colour change then down time 2 hours (Two time per 15 days).
Indigo Denim Manufacturing Process
Yarn Peperation
↓
Continuous Dyeing
↓
Beaming
↓
Slashing
↓
Weaving
↓
Finishing
Dyeing Machine Process
Continuous dyeing of cotton yarn with Indigo Dyeing Machine
Indigo denim dyeing:
The “Mult-dip” process is by far the only continuous method adopted for indigo yarn dyeing.
The dyeing machineries used for yarn dyeing are divided into two categories namely the rope dyeing range and the slasher dyeing range.
The main difference between rope dyeing and slasher dyeing is that for rope dyeing and sizeing have to be done separately while in slasher dyeing, the dyeing and sizing can be done simultaneously.
Rope dyeing technique is more popular in the America region. It is suitable for mass production. And because of its possible non stop dyeing advantage, rope dyeing gives better shade consistency.
Indigo Dyeing Machine wetting
In absence of strong demands for deep (dark) dyeing of yarns, they are only pre-wetted by caustic and wetting agent the degree of dyeing depth is influenced in the second trough rinsing is done more or less by strong overflow of cold
Pretreatment process with sulphur black
In general with continuous dyeing no deep (dark) dyeing of yarn is achieved, they are often pre-dyed to a light medium grey-shade with sulphur Black.
The pre-dyeing is done is done at 80ºC/90ºC in the first wetting trough of the continuous processing plant. The second trough is used for rinsing of dye stuff
The yarn is squeezed to 70% to 80% and the rest humidity is immediately passed through the first vat.
The Dyeing Process
The sequence of dyeing for both rope & slaser are very similar, which include the following stages:
Mercerization (Optional)
↓
Pre-Scouring
↓
Dyeing
↓
Squeezing
↓
Airing
↓
Rinsing
↓
Finished fabric.
Pre-Scouring:
Pre-Scouring has the following functions: wetting out yarn, removing air from yarn and scouring to give cleaner yarn so that a better dyeing can be achieved.
The pre-scouring bath consists of wetting agent, caustic soda and chelating agents. Normally, a minimum of two boxes are required to give satisfactory pretreatment. The first box is the pretreatment with temperature at 85ºC to wet out the yarn. The second
Box is a cold rinsing to coon down and to decrease the yarn.
It also a common practice where at this stage optional Sulphur bottoming application is done.
Dyeing
The desired depth of Indigo on the yarn is mainly achieved by the number of dip. In general, the lower the dye bath concentration (2-4 g/l) as more dips are required, the better the fastness, and the vice versa. For a full Navy shade of about 2% pick up (based on Indigo grain), an initial dye bath will balance itself until it is able to pick up 2% dye.
The reduce Indigo Dyeing Machine solution cannot be prepared directly in the dye baths. Its because it will take much higher quantity in caustic and hydrosulphite, and much longer tome to reduce the Indigo when the concentration of Indigo dyeing is a continuous exhaust dyeing process, a replenishing of dye and chemicals are necessary during dyeing. As a result, preparation of concentrated stock vat is necessarsy for the initial dye bath and the replenishment.
Indigo dyeing is generally carried out at room temperature, although dyeing at higher temperature has a better leveling effect. High temperature will deteriorate the reduction condition of the dye bath at much faster rate. As a result, a higher consumption of caustic and hydro.
In order to produce a consistent dyeing, control over the dye concentration, redox potential and the alkalinity of the dye bath is absolutely necessary.
Indigo Dyeing Machine
Control during dyeing
Hydrosulphite or ORP value
The content can either be checked by a vatometer, range from 1.5-2.5 g/l, or by direct titration method. The control can further be confirmed by measurement of the redox potential of the dye means of an ORP meter range from 730mv-860mv is common.
Caustic soda or pH value
The content can be checked either by titration with HCl or by pH meter, generally pH ranges from 11.5-12.5.
Dye concentration in dye bath
It can be checked by means of leuco solution is oxidized and the transmittance at λ max is measured. The reading can be converted into concentration in g/l by comparing with a calibration curve plot from known dye concentration.
The control figure varies from range to range, so one must establish their own set of control data.
Normal running speed is 20-25 yds/min (18-22 m/mim).
The longer the dipping time, the better will be the penetration and the lesser will be the ring dyeing effect. Dipping time varies from 6-30seconds. The common is 20-30 sec. However, the dipping time should not exceed 60 sec. It is because there is an adverse effect where the Indigo Dyeing Machine fixed on the yarn may be redused back into the dye bath.
However, for super dark shade, beside mercerization of yarns at the pretreatment stage, bottom or topping with Sulphur Black is also a common practice further; there is a newer practice by controlling the pH with the additional of buffer to give significant ring effect which enhances darker shade.
Squeezing
The wet pick up affects the dyeing fastness to a very great extent. Higher squeeze pressure gives lower wet pick up and results in lesser surface colour and better penetration.
Rope dyeing and Looptex units have squeeze pressure from 5-10 Newtons, which can give a wet pick up as low as 60% while for slasher dyeing range have inferior fastness property than the rope dyeing range.
Hardness of the squeezing rollers should be approximately 70-75ºShore. If the squeezing rollers are too hard, slippage will occur and results in uneven yarn tension. If they are too soft, they will groove easily and results in shading.
Maintaining in a smooth surface of the squeezing roller is important. Normally the surface should be ground twice per year. When applying pressure to the squeezing mangle, make sure the mangle is not bended. Otherwise, shading will result.
Oxidation
In between dipping, airing is necessary to oxidize the dyed yarn. Usually, airing time varies from 60-120 sec, and 90 sec is common. Try to avoid long airing time, as this will create unnecessary high tension on the yarn and make the subsequent processes difficult.
Rinsing
Most dye ranges are equipped with2-3 rinse boxes. Cold rinsing is generally sufficient. For rope dyeing, the last box is used for applying re-beaming aid.
Drying
Sufficient drying capacity should be provided, otherwise high range speed cannot be achieved. Insufficient drying or unevenly dried yarn will result in weak size pick up in the case of slasher and poor re-beaming in case of rope dyeing.
Preparation of stock vat, chemicals, dye bath
Preparation of stock vat
Since the dyeing is a wet on wet process, to limit the excess amount of liquid feeding into the dyeing system, it is always advisable to make up the stock vat as concentrated as possible.
During the preparation of the stock vat, there are certain points which need to be observed. First, the vatting temperature should be about 40-45ºC. Second, stirring is to be kept to the minimum, as unnecessary stirring will introduce oxygen into the stock vat and affect the stability of the reduced vat. Third, volume and concentration of the stock vat must be kept constant for every stock vat batch, for the constant volume and concentration will ensure a consistent replenishing amount.
A typical vatting procedure is as follows:
a) Make a mark on stock vat tank so that the volume is easily maintained by watching the level.
b) Add require amount of dye.
c) Add requires amount of NaOH, 50% liquid is preferred, as it generates lesser heat.
d) Add require amount of auxiliaries, chelating agent, wetting and dispersing agent. This is optional as both our paste and grain already have a certain amount of auxiliaries built in.
e) Add water to half the volume of stock vat. Stir for 5 min until the mass in the smooth slurry.
Dyes and Chemical:
Vat dyes (indigo)
Sulpher dyes (Black, Yellow, Green)
Caustic
Primasol
Triplex
Setamol
Hydeose
Sodium stone
Common salt
Sobitol
Rucowet
ASD
Peroxide
Acetic Acid
Starch
Size-ca
PVA
Wax
Etc
Dyeing Recipe:
2% shade for indigo (blue) dyeing
Scouring
Caustic soda : 5 g/l
Wetting agent : 5 g/l
Squesting agent : 2 g/l
Dyeing
Vat (indigo) : 2%
Reducing agent (Hydro) : 4%
Caustic : 90 g/l
wetting : .25%
Sizing: (for 650 Lts)
Starch : 75 kg
PVA : 20 kg
Size CA : 20 kg
Wax : 5 kg
water : 470 lts
Dyeing Recipe:
2% shade for Blue Black dyeing
Hard Bottoming
Sulphur Black : 45 g/l
Sodium Sulphide : 67.75 g/l
Caustic soda : 10 g/l
Wetting agent : 5 g/l
Squesting agent : 2 g/l
Dispersing agent : 3g/l
Dyeing
Vat (indigo) : 2%
Reducing agent (Hydro) : 4%
Caustic : 90 g/l
Wetting : .25%
Sizing: (for 650 Lts)
Starch : 75 kg
PVA : 20 kg
Size CA : 20 kg
Wax : 5 kg
Water : 470 lts
Dyeing Recipe:
Sulphur Black dyeing
Hard Bottoming
Caustic soda : 40 g/l
Wetting agent : 5 g/l
Squesting agent : 2 g/l
Dyeing
Sulphur Black : 7%
Sodium Sulphide : 10.5%
Caustic soda : 20 g/l
Wetting agent : 5 g/l
Squesting agent : 3 g/l
Dispersing agent : 2g/l
Sizing: (for 650 Lts)
Starch : 75 kg
PVA : 20 kg
Size CA : 20 kg
Wax : 5 kg
Water : 470 lts
Sizing
Natural Indigo Dyeing Machine -Sizing is a process where sizing is done to prepare the warp to with stand the weaving operation by binding together the fabric in the yarn to increase its strength by covering yarn with a thin film of size when binds the protruding fibre obtain smooth surface
To improve abrasion resistance of the yarn
To reduce hairiness of yarn to obtain smooth surface
To reduce generation of static charge for polyester blend yarn.
To improve breaking strength of cellulose yarn from Indigo Dyeing Machine
Written By – Farid Ahmed, General Manager, Knit Dyeing Textile Ltd. Epz, Savar, Dhaka
