Study on cost effectiveness of silk dyeing with acid dyes and basic dyes

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Bangladesh University of Textiles
Project title
Study on cost effectiveness of silk dyeing with acid dyes and basic dyes
Examination 2014
Supervised by
Dr. Mohd. Forhad Hossain
Assistant Professor & Head, Department of Wet Process Engineering
Bangladesh University of Textiles
Submitted by
Student Name ID
Md. Al-Amin 2011-01-049
Shakil Mahmud 2011-01-097
Nazmun Nahar 2011-01-098
Md. Ariful Islam 2011-01-140
Md. Saifur Rahman 2011-01-157

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Acknowledgement
Project work is essential in order to make us enable to carry out potential research work in
relevant field. This will also enhance our analytical skill in finding out the root of a problem
and to solve that.
While we are of course solely responsible for the contents in our research on “Study on cost
effectiveness of silk dyeing with acid dyes and basic dyes. “In completing of our project work
at first we are grateful to almighty ALLAH and then come to the human league who contributed
a lot to make our project a solid one.
We would like to thank our project supervisor, Dr. Mohd. Forhad Hossain (Assistant Professor
& Head, Dept. of Wet Process Engineering), BUTex, for his supervision, advice and guidance
from the very early stage of this research. In spite of his busy work schedule he had helped us.
This paper would not have been possible without his vital encouragement, inspiration and
support. We are thankful for his numerous fruitful discussions and guidance with the valuable
data that we needed for carrying out our research.
We would also like to express our deep gratitude to Prof. Dr. Md. Zulhash Uddin (Dean,
Faculty of Textile Chemical Engineering), BUTex, for his patient guidance, enthusiastic
encouragement and critique of this research work and for his advice and assistance for our
progress on schedule. At all stages of the report has benefited tremendously from his support.
We appreciate his advice, comments and willingness to discuss any questions and ideas that
we have had.
We owe a particular debt of gratitude to the management of Orient Chem-Tex Ltd. for helping
us in carrying out this research work. Especially we are very thankful to Md. Mukhless ur
Rahman Khan (Director- Technical & Marketing, Orient Chem-Tex Ltd), Sazzad Wahid
(Marketing Executive), Sabitry Rani Das (Head of Laboratory) for their technical support.

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Abstract
Silk has always been the emblem of royalty due to its delicate lustrous appearance, peach like
softness and draping qualities for over thousands of years. It is a natural fibre with great
importance in the garments and clothing industry. The coloration of this valuable and high
prized fiber is also an art form. Silk dyeing is normally done either in the form of hanks or
woven pieces. Its hydrophilic characteristics and amphoteric properties enables it to be easily
dyed. There remains a numerous ranges of dyestuff to be applied on silk. Different class of
dyestuffs used for cotton or wool, can be used on silk with good result from the point of view
of dye ability with unsatisfactory level of fastness. In general, the dyestuffs are applied by
techniques similar to those of wool or cotton.
In this project, silk is dyed with acid and basic dyes after degumming it to remove sericin.
Fixation is carried out after dyeing to improve wet fastness of silk which has become an
important goal of silk dyer in order to meet customer requirements.
This project report aim to make a comparative analysis of silk dyeing with acid dye, which is
commonly applied on nylon, wool, silk and basic dye, which is more commonly used with jute,
acrylic. This study emphasizes on the total costing for dyeing, different types of fastness
properties (light, wash, rubbing and perspiration), dye uptake of the dyed samples. 0.5%, 1%,
2%, 3%, 4% red, blue and yellow shades were prepared for silk dyeing both by acid dye and
basic dye according to the dyeing method specified the dyes supplier. It is found that acid dyes
show higher dye uptake for red shade while basic dyes show better dye uptake for blue and
yellow shade. Color fastness tests on silk for acid dyes generally show better performance but
in case of color fastness to rubbing and perspiration tests both dyes show similar result. Dyeing
with basic dyes is comparatively economical than acid dyes as basic dyes are cheaper. As
fastness properties are given priority for fabric dyeing, in this case acid dyes are more suitable
for silk.
Keywords: Silk, dyeing, color fastness, shade%, costing.

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Table of content
Chapter 1: Introduction
1.1 General Introduction……………………….……………………………..
1.2 Objectives…………………………………………………………….…..
Chapter 2: Literature review
2.1 Introduction……………………………………………………………....
2.2 Microscopic structure of silk…………………………...…...…………....
2.3 Chemical composition of silk………………………………...…………..
2.4 Chemical structure of silk……………………………………...………...
2.5 Silk producing countries……………………………………………….....
2.6 Properties of silk…………………………………………………..……...
2.7 Uses of silk…………………………………………………………….....
2.8 Treatment and processing of silk………………………………………...
2.8.1 Pretreatment……………………………………………………………...
Degumming
Bleaching
2.9 Applicable dyes for silk…………………………………………………..
2.9.1 Acid dyes…………………………………………………………………
2.9.1.1 Common properties of acid dyes………………………………………....
2.9.1.2 Chemical structure of acid dyes……………………………………….....
2.9.1.3 Classes of acid dyes……………………………………………………....
2.9.1.4 Dyeing mechanism of acid dye on silk…………………………………..
2.9.2 Basic dyes…………..…………………………………………………....
2.9.2.1 Properties of basic dyes…………………………………………………..
2.9.2.2 Chemical structure of basic dyes…………………………………………
2.9.2.3 Dyeing mechanism of basic dye on silk…………………………….........
2.10 Kubelka Munk Equation ………………………………………………...
2.10.1 Color saturation measurement principle by spectrophotometer…...…..…
2.11 Conclusion……………………………………………………………….
Chapter 3: Materials and Methods
3.1 Introduction…………………………………………….………………...
3.2 Materials………………………………………………………………….
3.2.1 Fabric……………………………………………………………………..
3.2.2 Pretreatment materials……………………………………………………
3.2.2.1 Degumming Chemicals…………………………………………………..
3.2.3 Dyeing materials…………………………………………………………
3.2.3.1 Dyes………………………………………………………………………
3.2.3.2 Chemical and auxiliaries………………………………………………...
3.3 Color fastness testing chemicals……………………………….………...
3.4 Equipment……………………………………………………………….
3.5 Methods of silk dyeing…………………...................................................
3.5.1 Pretreatment of silk………………………………………………………
3.5.2 Silk dyeing with acid dyes…………………………………………...…..
3.5.3 Silk dyeing with basic dyes…………………………………………..….
3.6 Color fastness measurement……………………………………………..
3.6.1 Method and procedure…………………………………………………....
3.6.1.1 Color fastness to wash (ISO-105/ C06-C2S)………………………….….
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3.6.1.2 Color fastness to Rubbing (ISO-105/ X12)…………………………….....
3.6.1.3 Color fastness to perspiration (ISO-105/ E04)……………………….…...
3.6.1.4 Color fastness to light (ISO-105/ B02)……………………………….…..
3.6.2 Shade performance measurement…………………………………….…..
3.7 Conclusion…………………………………………………….……….....
Chapter 4: Result and Data
4.1 Introduction…………………………………………………………….....
4.2 Data on color strength………………………………….……………........
4.3 Result on color fastness………………………………….…………...…..
4.3.1 Color fastness to light …………………………………….……….…......
4.3.2 Color fastness to washing………………………………….…….…….....
4.3.3 Color fastness to Rubbing………………………………….…….…….....
4.3.4 Color fastness to perspiration ……………………………….….…….......
4.4 Costing……………………………………………………………………
4.4.1 Costing with acid dyes……………………………………..…………......
4.4.2 Costing with basic dyes……………………………………..………........
4.5 Conclusion ……………………………………………….….……...........
Chapter 5: Discussion
5.1 Introduction ………………………………………………….….….…….
5.2 Comparison on the basis of color strength………………………….…….
5.3 Comparison on the basis of color fastness……………………..................
5.4 Comparison on the basis of Costing ……………………………….……..
5.6 Comparison on basis of all parameters…………………………….…......
5.7 Conclusion…………………………………………………………..…….
Chapter 6: Conclusion
6.1 General conclusion…………………………………………………..…….
6.2 Recommendation………………………………………………….....…….
6.3 Limitations…………………………………………………………...……
References……………………………………………………….….…......
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Chapter 1: Introduction
1.1 General Introduction
Silk is an animal fiber, and therefore, like all animal fibers, is made of protein, due to this,
mechanism of dyeing silk is dependent mainly on free amino and carboxyl groups. Anionic
dyes such as acid, metal complex, reactive and selected direct dyes are suitable for dyeing
silk as it is slightly cationic with iso electric point at above pH 5 [1]. Silk offers a wide
coloration possibility covering almost the entire spectrum of colors. But the main objective
of coloration of a textile fibre is that the permanency of the color and should not allow
damage of natural abstract of fibre. This implies that it should not destroy its color during
processing following coloration and dyeing & subsequent useful life (i.e. washing, light,
rubbing, perspiration). So whatever dyestuff we use for silk dyeing it is very essential to
have permanency of that dyestuff [2].
In this study there are three major components which are silk fibre, acid dyes and basic
dyes. This report starts with some information on the silk fibre, about acid dyes, basic dyes
and progressed with mentioning the required material and equipment for silk dyeing from
pretreatment to performance evaluation.
Sericin, a group of soluble glycoprotein, normally present in the silk, which essential to be
removed from silk before dyeing it by degumming process to facilitate better luster and
color.
During dyeing, anionic dyestuffs namely acid and cationic dyes namely basic dyes form a
'Dye-Fibre' complex by electrostatic and hydrogen bonds [3]. This mechanism requires an
acidic medium to be activated. Exhaustion of dye from the bath requires a proper
controlling of the specified and recommended dyeing parameter. 0.5%, 1%, 2%, 3%, 4%
red, blue and yellow shade were prepared for silk dyeing both by acid dye and basic dye
according to the dyeing method specified the dyes supplier. Acid dyes were applied on silk
at 980
C for 60 min while for basic dyes 800
C temperature for 40 min is maintained. Dyeing
procedures of basic dyes were almost similar to the dyeing procedures of acid dyes.

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Fixation treatment sometimes carried out on colored silk with a view to increase its fastness
behavior.
One of our main target is total costing evaluation for dyeing silk both by acid and basic
dyes. To evaluate the resistance to color fading especially to wash, rubbing, and
perspiration, light of acid and basic dyed silk fabrics is also our another target of this
project. Shade strength measurement using data color is also another technical aspect.
Comparison and decision is then made by mentioning that which one is better for silk from
the point of view of costing, fastness etc. Finally, our study is concluded by mentioning
some limitations of us about this project.
1.2 Objectives
The aim of the project is to find out the suitability of silk dyeing with acid and basic dyes from
aspect of economic and technical project of view.
To achieve this aim, the following objective were set:
i. To evaluate which dyeing method is economical for silk from acid and basic dyes.
ii. To find out the dye uptake of the dyed samples.
iii. To find out the dye that gives better performance (wash, rubbing, perspiration, light
fastness).
iv. To analyze different results, compare them graphically and finding out some
decisions from them regarding the preference a suitable dye on silk from acid and
basic dye.

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Chapter 2: Literature review
2.1 Introduction
Silk is called “Queen of fibres”, is a continuous protein fibre produced by silkworm so as to
form its cocoon. The silk. fibre is also produced by some spiders belonging to the Arachina
family. Unlike the silk worm’s fibre, the spider’s fibre cannot be commercially produced, and
therefore the silk fibre referred to in this work is the fibre coming from the silkworm. Most
historians agree that silk and sericulture the cultivation of silkworm had their origin in China
nearly 2500 BC. After finding this knowledge China kept it as a secret and held a monopoly in
the silk industry for nearly 4000 years. After this period, sericulture spread to Korea and Japan
and it also spread around the world.
Silk fibre is natural protein fibre. Unlike wool, silk contain very small amount of sulphur. There
are two main types of silkworm, mulberry silk also called ‘cultivated silk’ and wild silk of
which Tussah silk is the most important representative.
2.2 Microscopic structure of silk
Microscopic structure includes longitudinal and cross section. It means the fibre length,
fineness, crimp, color, &luster, surface contour, irregularities. Silk fibres are straight and
smooth. Raw silk fibre composed of two filaments, has elliptical shape under the microscopic.
Wild silk or tussah fiber has different appearance than cultivated silk. It is flattened, coarse,
thick & and broader fiber having fine wavy lines all across its surface where cultivated silk is
narrower fibre. Silk as is more crystalline as their molecules are highly oriented along the fibre
axis. As silk fibre from silk worm, is extruded out from the two glands, they are present as
triangular filaments, which are attached by gum named as sericin (Morton and Hearle, 1986).

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Fig. 2.1 Microscopic appearance of silk [4]
2.3 Chemical composition of silk
The strands of raw silk as they are unwound from the cocoon consist of the two silk filaments
mixed with sericin and other materials [5].
Fibroin 76%
Sericin 22%
Fat & wax 1.5%
Mineral salt 0.5%
2.4 Chemical structure of silk
Silk is comprised of a simple protein named as fibroin. Fibroin has a similar X-ray diffraction
pattern as Beta-keratin structure. The sulphur groups are very few. The main interaction
between the molecules are by hydrogen bonding and salt linkages. The X-ray diffraction
photography has shown that the silk in the crystalline part needs to be in fully extended chains.
Silk is made up of the amino acids GLY-SER-GLY-ALA-GLY and forms Beta pleated sheets.
The main amino acid is GLY or glycine. The three amino acids bond into a long chain that is
repeated and then the large amount of the acids for the Beta pleated sheets. This is the polymer
that is known commonly as silk. Silk is a natural polymer and it is found
in spiders and silkworms.

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Fig. 2.2 Chemical structure of silk fibroin [6]
2.5 Silk producing countries
Silk came from China to Persia, Korea and Japan. Up until the 13th century silk was only
available as an oriental import and only very wealthy people could afford it. In Europe,
southern Italy, while under Norman rule became an important center for breeding silkworms
and spinning silk. For a long time, Italy remained the leading silk country in Europe until
France expanded its silk weaving in the middle of the 17th century and surpassed Italy. China,
India, Uzbekistan, Brazil, Japan, Republic of Korea, Thailand, Vietnam, DPR Korea, Iran, etc.
are the major silk producer. [7]
2.6 Properties of silk
Physical properties of silk given below [8]
i. Color: The color of silk fiber could be yellow, brown, green or grey.
ii. Tensile strength: The strength is greatly affected by moisture; the wet strength of silk is
75 – 85%, which is higher than dry strength.
iii. Elongation at break: 20 -25% at break.
iv. Elastic recovery: Not so good.
v. Specific gravity: Specific gravity is 1.25 to 1.34.
vi. Moisture regain (R %): Standard moisture regain is 11% but can absorb up to 35%.
vii. Effect of heat: Silk will withstand at higher temperatures than wool. It will remain
unaffected for prolonged periods at 1400
C. Silk decomposes at 1750
C.

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viii. Effect of sun light: Sun light tends to encourage the decomposition of silk by
atmospheric oxygen.
ix. Luster: Bright.
Chemical properties of silk given below [8]
i. Effect of acids: The Fibroin of silk can be decomposed by strong acids into its constitute
amino acids. In moderate concentration, acids cause a contraction in silk. Dilute acids
do not attack silk under mild conditions.
ii. Effects of alkalis: Silk is less readily damaged by alkalis than wool. Weak alkalis such
as soap, borax and ammonia cause little appreciable damage. Silk dissolves in solutions
of concentrated caustic alkalis.
iii. Effect of organic solvent: Silk is insoluble in the dry-cleaning solvents in common use.
iv. Effects of Insects: Insect does not affect silk.
v. Effect of Mildew: Silk is affected by mildew slightly.
Here effect of acid, effect of alkali, effect of organic solvents, effect of moisture regains etc.
characteristics influence largely in dyeing of silk
2.7 Uses of silk
Silk has been the queen of fibres for centuries. It is used for luxury fabrics and high fashion
cloths and items but its durability extends its use to sports-wear and other contemporary
applications. Because of the unique characteristics and comfort properties, silk is used in both
apparels such as saris, dress, shirts, suits, pants, socks, etc. and home furnishings such as
upholstery fabrics, blankets, bed sheets etc. Moreover, as silk proteins amino acid composition
is close to that of the human skin, it is also used in biomedical applications such as medical
sutures, prosthetic arteries, etc. [9].

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2.8 Treatment and processing of silk
2.8.1 Pretreatment
Pretreatment means any treatment, which is done before actual (dyeing) process. For silk
fabric, Degumming/Scouring is generally carried out as preparatory process.
Degumming
Silk fibre contains approximately 20-25% Sericin gum. Sericin is a group of soluble
glycoprotein’s expressed in the middle silk gland of Bombyx mori. Silk emitted by the
silkworm consists mainly of two proteins, sericin and fibroin; fibroin being the structural center
of the silk, and sericin being the gum coating the fibres and allowing them to stick to each
other. The chemical composition of sericin is C30H40N10O16. The process of eliminating “Gum
(sericin)” from raw silk is known as degumming of silk. Degumming of silk involves mainly
the removal of sericin from the fibroin. Sericin is insoluble in water. It is comparatively easily
hydrolyzed whereby the long protein molecule of sericin is broken down into smaller fractions,
which are easily dispersed or solubilized in hot water. Hydrolysis of proteins can be carried out
by treatment with acids, alkalis and enzymes. Acids are non-specific and tend to
attack vigorously. Alkalis also attack both, sericin and fibroin. However, the variation in the
rate of hydrolysis is large enough to control the reaction. Removing the gum improves the
luster, color, hand, and texture of the silk.It is also known as silk scouring [10].
Bleaching
The silk being spun by silkworm contains natural colouring matter tinted with yellow, yellow
-green and brown pigments. During degumming the removal of sericin from the silk results in
dull white to lightly tinted material. Since some of the sericin is closely held by fibroin,
complete elimination of the colour by degumming is not possible. During bleaching these
natural colouring matters are decolorized /removed to produce pure white material. An efficient
bleaching process must ensure pure whiteness and level dyeing properties and non- degradation
of the material. The bleaching of silk is based on the use of either reducing agents or oxidizing
agents.

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2.9 Applicable dyes for silk
Normally acid dyes, reactive dyes, selected direct dyes are used for silk dyeing worldwide. But
at present basic dyes, vat dyes, metal-complex dyes etc. are also used.
2.9.1 Acid dyes
2.9.1.1 Common properties of acid dyes
Acid dyes are highly water soluble, and have better light fastness than basic dyes. They are
anionic in nature. They are suitable for wool, silk, polyamide and modified acrylics. These are
applied from a strongly acidic to neutral pH bath. These dyes combine with the fiber by
hydrogen bonds, Vander Waals forces or through ionic linkages. Acid dye is a sodium or
ammonium salt of a sulfuric, carboxylic or phenolic organic acid.
2.9.1.2 Chemical structure of acid dyes
These dyes are normally very complex in structure but have large aromatic molecules, having
a sulphonyl or amino group which makes them soluble in water. Most of the acid dyes belong
to following four main structural molecules: [11]
i. Anthraquinonetype: Many acid dyes are
synthesized from chemical intermediates which
form anthraquinone-like structures as their final
state.
Fig. 2.3. Anthraquinone derivatives
generally form blue dyes
ii. Azo dye type: The structure of azo dyes is based on
azobenzene, Ph-N=N−Ph and most are red in color.
Fig. 2.4 Azobenzene derivatives
generally form red dyes

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iii. Premetallized acid dyes: Fall into two classes, 1:1
metal-complexes, in which one dye molecule is
complexed with one metal atom and the more
modern 1:2 metal complexes, in which one metal
atom is complexed with two dye molecules.
Fig. 2.5 Pre- Metalized Acid Dye
iv. Triphenylmethane type: Acid dyes having
structures related to triphenylmethane predominate
in the milling class of dye.They are mainly yellow
and green dyes.
Fig. 2.6 Triphenylmethane derivatives
generally form yellow or green dyes

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2.9.1.3 Classes of acid dyes
Acid Dyes fall into 3 subgroups or classes that describe their properties in the dyeing process.
The three classes are leveling, milling/super milling and pre-metallized.
Table 2.1: Characteristics of the various classes of acid dyes
Property
Leveling Acid
Dyes
Milling/Super milling
Acid Dyes
Pre-metallized
Acid Dyes
Color Brightness Very Bright Bright
Duller, more
earthy
Leveling tendency
(evenness of color)
Very Good Ok Fair
Wash Fastness Good to 105˚F Very good to 120˚F Excellent to 140˚F
Light Fastness
Good in most
cases
Good in most cases Excellent
pH of dyebath 2-4 4-7 2-7
Additives for dyebath
Acid,
Glauber's salt
Acid, Ammonium
Sulfate
Acid, Ammonium
Sulfate
Solubility in water 40-80 g/l 3-30 g/l Varies

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2.9.1.4 Dyeing mechanism of acid dye on silk
They contain sulphonic acid groups, which are usually present as sodium sulphonate salts.
This increase solubility in water, and give the dye molecules a colored anion.
Fig.2.7 colored anion formation of acid dye [2]
In an acidic solution, the -NH2 functionalities of the fibres are protonated to give a positive
charge: -NH3+. This charge interacts with the colored anion, allowing the formation of ionic
interactions. As well as this, Van-der-Waals bonds, dipolar bonds and hydrogen bonds are
formed between dye and fibre.
Fig. 2.8 Reaction of Silk with Acid Dye [12]

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2.9.2 Basic dyes
2.9.2.1 Common properties of basic dyes
The outstanding characteristics of the basic are brilliance and intensity of their colors. The
bright colors achieved from basic dyes do not usually occur with other dye classes. Many of
the basic dyes are sparingly soluble in water. The addition of glacial acetic acid helps to
dissolve the basic dye quickly in water. Basic dyes are readily soluble in alcohol or mentholated
spirit. The basic dyes are poor fastness to light and vary with regard to washing fastness from
poor to moderate. An important property of basic dyes is that they will combine with tannic
acid to form an insoluble compound provided mineral acid is absent. The wet fastness of the
basic dyes on protein fibers can also be improved by back tanning. The basic dyestuff will
combine with direct or Sulphur or some acid dyestuffs. So they cannot be used together in the
same bath. But basic dyestuffs are used in after treating cotton or other materials dyed with
direct colors [8].
2.9.2.2 Chemical structure of basic dyes
There are many dyes belonging to this class. The more important groups are described here
[13]
Group 1: Derivatives of triphenyl methane
Fig.2.9 Malachite Green
Group 2: Derivatives of thiazine
Fig. 2.10 Methylene Blue

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Group 3: Basic dyes containing oxazine group
Fig. 2.11 Meldola Blue
Group 4: Basic Dye containing azines
Fig. 2.12 Neutral Red
Group 5: Xanthene Basic Dyes
Fig.2.13 Rhodamine B
Group 6: Basic dyes containing azo groups
Fig. 2.14 Bismarck brown
2.9.2.3 Dyeing mechanism of basic dye on silk
Basic dye is a cationic dye. When it is introduced in an acidic medium it readily splits into
positive and negative parts. Here negative part does not show any color. Positive cationic part
is solely responsible for color production. Negative side of protein fiber comes closer to the
positive side of basic dye and forms bond. The bond formed this way yields bright color.
Fig: 2.15 Mechanism of basic dyeing on cellulose and protein fiber.

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2.10 Kubelka- Munk equation
𝐾
𝑆
=
(1 − 𝑅)2
2𝑅
Where,
R= Reflectance; K= Absorption Co-efficient; S= Scattering Co-efficient
2.10.1 Color saturation measurement principle by spectrophotometer
The sample is mounted on the integrated sphere. The light is passed through the lens to the
diffraction grating. When the diffracted light is fall on the detector, it measures the light
attributes and a microprocessor computes and give the results [14].
2.11 Conclusion
Silk is comprised of a simple protein named as fibroin. The main interaction between the
molecules are by hydrogen bonding and salt linkages. It can be decomposed by strong acid and
damaged by alkalis. It contains sericin in its structure that has to be removed by degumming
process. It is commonly dyed by acid & reactive dyes but we have researched silk with acid
and basic dyes. Acid dye is an anionic dyes and its anion is responsible for the coloration. Basic
dye is a cationic dye which is renowned for its brilliant color and intensity.
Fig. 2.15. Single beam spectrophotometer

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Chapter 3: Materials and Methods
3.1 Introduction
In this work has given importance to the materials and methods. This is reason of getting the
perfect result and output of the process from the project. Selection of material and methods is
essential for this project. This project has done based on the fabric, dyes, chemical and
auxiliaries. We have conducted our research with three major raw materials – silk fabric, acid
dye, basic dye followed by using different chemicals and auxiliaries, equipment in different
methods. In the pretreatment, dyeing, after treatment and dye uptake test and fastness tests need
to apply best method using suitable recipe and equipments. In this chapter silk dyeing with acid
and basic dyes for red, blue, yellow shade is done using appropriate procedure for achieving
perfect result.
3.2 Materials
3.2.1 Fabric
The silk fabric, that is collected by purchasing from The Sopura silk mills Ltd., Dhanmondi.
3.2.2 Pretreatment materials
3.2.2.1 Degumming Chemicals
Synthetic Detergent (Nonyl Phenol Ethoxylate), Soda ash, Sequestering agent (SQ-117CA),
Wetting agent (KS-10)
3.2.3 Dyeing material
Materials for Dyeing - Acid dyes, Basic dyes, chemical and auxiliaries.
3.2.3.1 Dyes
Red, blue and yellow colored acid and basic dyes were used for silk dyeing in powder form.

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Table 3.1 Sourcing of dyes for dyeing silk.
Name Brand Name Manufacturer Country Source Place of Source
Acid Dyes Erionyl Huntsman Thailand collected Swiss colors
Basic Dyes Taiacryl T& T Taiwan Collected Imperial
3.2.3.2 Chemicals & auxiliaries
For silk dyeing with acid dye, levelling agent, buffer is used (pH maintain 4.5) while levelling
agent, acid (pH maintain 4.5) is used for silk dyeing with basic dye. Soaping agent is used for
both but fixing agent is only for acid dyeing process.
Table 3.2 Sourcing of chemicals and auxiliaries for dyeing silk
Name Brand Name Manufacturer Country Source Place of source
Levelling Agent Albagal Huntsman Thailand collected Swiss colors
Buffer Albatex Huntsman Thailand collected Swiss Colors
Acetic Acid Neutra Tubingen Bangladesh collected Orient-Chem
Soaping Agent Eriopon OS Huntsman Germany collected Swiss colors
Fixing Agent Erional FRN Huntsman Thailand collected Swiss colors
Glauber salt Sateri Tubingen Bangladesh collected Orient- chem

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3.3 Color fastness testing chemicals
Name Process
-ECE (Detergent),
- Soda ash
- Sodium per borate
washing fastness
- L-Histadine mono-hydrochloridemonohydrate
- Disodiumhydrogenorthophosphate dehydrate
- Sodium Chloride
- HCl
Perspiration fastness
3.4 Equipment
There are different types of equipment needed for pretreatment, dyeing and testing silk.
Table 3.3 Equipment required for dyeing and testing silk
Name Brand name Steps
Lab Dyeing m/c IR Dyer Degumming, coloration
CCMS/ Data color 650 Shade strength,dye up-take
Washing machine Labtec Wash Fastness Test
Crock meter Crockmaster Rubbing Fastness Test
Xenon light box Q-sun Light Fastness Test
Incubator Labtec Perspiration fastness test

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3.5 Methods of silk dyeing
3.5.1 Pretreatment of silk
Degumming of silk with synthetic detergents (Non-ionic product like Nonyl phenol
ethoxylated) is carried out as pretreatment of silk.
Recipe for silk degumming with synthetic detergent
Synthetic Detergent (Nonyl Phenol Ethoxylate) : 3g/l
Wetting agent (KS-10) : 2.5 g/L
Sequestering agent (SQ-117CA) : 0.5 g/l
Soda ash : 2 g/l
pH : 11.5
Water : 27.9cc
M: L : 1:10
Temperature : 950
C
Time : 40min
Stock solution: 10 % For Wetting Agent
10 % For Sequestering agent
20 % For Soda Ash
Procedure of degumming
The bath was set with substrate at room temperature and KS-10 (wetting agent), SQ-117CA
(Sequestering agent) and detergent was added to it. Then temperature was raised at 2°C /min
to 80°C and then pH was maintained to 11.5 by adding soda ash. After that, temperature was
raised to 95°C and ran for 40 minutes for optimum removal of sericin gum. The bath was cooled
down to 60°C and then the bath was dropped. At last, it was washed with warm and cold water
successively.

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Process curve of degumming
Fig 3.1 process curve of degumming of silk by detergent
3.5.2 Silk dyeing with acid dyes
In this project, total 15 samples were dyed with Acid dye by lab dyeing machine (IR Dyer).
5 samples for 0.5%, 1%, 2%, 3%, 4% Red shade,
5 samples for 0.5%, 1%, 2%, 3%, 4% Blue shade,
5 samples for 0.5%, 1%, 2%, 3%, 4% Yellow shade.
Recipe for acid dye
For 4gm Silk fabric sample -
Acid Dyes (Erionyl) - 3% owf)
Albatex AB 45 (Buffer to maintain pH 4.5) - 1.0 g/l
Albagal SET (Levelling Agent) - 1.0 %
M: L - 1:10
Temperature - 98°C
Time - 60min

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Dyeing procedure of silk with acid dye
At first dye solution was prepared. Then dye paste was prepared by adding water with dyes,
then hot water was added with stirring to produce desirable dye solution.
Albagal SET (Leveling agent) was taken into the dye pots. Dye solution for shade 0.5%, 1%,
2%, 3%, 4% respectively were added into the dye pots. Then remaining water was added. After
that Albatex AB 45 (buffer solution) was added to maintain pH 4.5. At last Silk fabric samples
weretaken into the pots. Dye bath was prepared at 500
C temperature. The dye pots were placed
in the dye bath and ran the bath for 10 minute at 500
C. Temperature was raised to 980
C at 10
C/ min rate. Dye bath was run for 60 min. Then bath was dropped at 60°C at 1.5o
C /min rate.
Dyeing curve of silk with acid dye
Fig 3.2 dyeing curve of acid dye on silk
After treatment
Dyed silk samples were rinsed with cold water. After that they were washed at 80°C for 5 min
with soaping agent Eriopon OS 1.0 g/l. Then the samples were rinsed again in cold water.
Fixing was done with Erional FRN 3.0% at pH 4.5 (with Albatex AB 45) at 80°C for 30
minutes. Then they were rinsed again with cold water. At last the samples were dried in dryer.

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3.5.3 Silk dyeing with basic dyes
In this project, total 15 samples were dyed with Basic dye by lab dyeing machine (IR Dyer).
5 samples for 0.5%, 1%, 2%, 3%, 4% Red shade,
5 samples for 0.5%, 1%, 2%, 3%, 4% Blue shade,
5 samples for 0.5%, 1%, 2%, 3%, 4% Yellow shade.
Recipe for basic dye
For 4gm Silk fabric sample-
Basic dyes (Taiacryl) - 3% (owf)
Albagal SET (Leveling Agent) - 1 %
Glauber Salt (Na2SO4.10 H2O) - 10 g/l
Acetic Acid (pH= 4.5) - 0.07 ml
M: L - 1:10
Temperature - 80°C
Time - 40 Min
Dyeing procedure of silk with basic dye
At first dye solution was prepared. Then dye paste was prepared by adding water with dyes,
then hot water was added with stirring to produce desirable dye solution.
Albagal SET (Leveling agent) was then taken into the dye pots. Then Glauber salt (Na2SO4.10
H2O) was added. Dye solution for shade 0.5%, 1%, 2%, 3%, 4% respectively were added into
the dye pots. Then remaining water was added. After that acetic acid solution was added to
maintain pH 4.5. At last Silk fabric samples were taken into the pots. Dye bath was prepared
at 400
C temperature. The dye pots were placed in the dye bath and ran the bath for 10 minute
at 400
C. Temperature was raised to 800
C at 1.50
C/ min rate. Dye bath was run for 40 min.
Then bath was dropped at 60°C at 1.5o
C /min rate.

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Dyeing curve of silk with basic dye
Fig 3.3 dyeing curve of basic dye on silk
After treatment
Dyed silk samples were rinsed with cold water. After that, hot wash wass given at 80°C for 5
min with a soaping agent Eriopon OS 1.0 g/l. Then the samples were rinsed again in cold water.
At last the samples were dried in dryer.

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3.6 Color fastness measurement
In this project, we have assessed total 4 types of color fatness test: color fastness to wash, color
fastness to rubbing (dry and wet), color fastness to perspiration (acidic and alkaline), Color
fastness to light.
3.6.1 Method and procedure
3.6.1.1 Color fastness to wash (ISO-105/ C06-C2S)
Color fastness to wash was measured with ISO-105/ C06-C2S method using 10 cm×4 cm dyed
silk sample and multifibre fabric with the washing recipe:
ECE (Detergent) - 3 g/l
Soda ash (pH 11) - 2 g/l
Sodium perborate (NaBO3.10 H2O) - 1 g/l
M: L - 1:10
Washing temperature - 600
c
Washing time - 30 Min
Test procedure
First condition the sample fabric for 4–6 hours. Then the sample fabric and multifibre fabric
are cut according to required size (10cm×4 cm) and the multifibre fabric is attached with the
sample fabric by sewing to make composite sample. After that a solution of 3gm/L ECE
detergent and 1gm/L sodium perborate is made. Soda ash is used to maintain pH 11. Then the
composite sample is washed for 30minutes at 600
C. In this method, 10 stainless steel ball were
used during washing to provide mechanical action each having diameter of 0.6 cm and weight
of 1 gm. Finally, the composite sample is dried not exceeding 600
C and detach the multifibre
fabric.
Color change and staining is then rated by grey scale.

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3.6.1.2 Color fastness to Rubbing (ISO-105/ X12)
The resistance of color of dyed silk to the action of rubbing (dry and wet) was evaluated with
ISO-105/ X12 method.
Sample preparation
Silk sample fabric : 14cm×5 cm
Cotton rubbing cloth : 5cm×5 cm
Requirements
Dry and wet (100%) silk sample fabric.
Test Procedure
First the sample is put in the crockmaster clamp. Then rubbing dry cloth is placed at the finger
for dry rubbing test. OK button is clicked to run the machine 10cycle / 10seconds. After that
the white rubbing test cloth is removed. Same procedure used for wet rubbing test. The wet
rubbing cloth is dried not more than 600
C.
Evaluating is done with grey scale with a rating of 1-5.
3.6.1.3 Color fastness to perspiration (ISO-105/ E04)
The resistance of color to the action of perspiration (acidic and alkaline) was measured with
ISO-105/ E04 method.
Sample preparation
Silk sample fabric : 10cm×4 cm
Cotton perspiration fabric : 10cm×4 cm
Required chemicals
i. L-histadine mono-hydrochloric hydrate - 0.5 gm/L
ii. Di-Sodium Hydrogen ortho phosphate di hydrate - 2.5 (alkaline) and 2.2gm/L (acidic)
iii. Sodium Chloride -5.0 gm/L
iv. pH (adjusted with 0.1N NaOH) -8 (alkaline) and 5.5 (acidic)

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Test Procedure
At first two silk sample and cotton perspiration fabric is cut into 10x4cm and then attached
these. The composite sample is immersed in the acid and alkali solution (individually). Then
placed it in a preheated perspirometer acrylic glass plate under the pressure of 12.5kpa and
placed the perspirometer in the oven incubator at 380
C for 4 hours. After that the perspirometer
is removed from the oven and remove the composite sample. Finally dried not exceeding 600
C
and detach the cotton perspiration fabric from silk sample.
Evaluating is done with grey scale.
3.6.1.4 Color fastness to light (ISO-105/ B02)
The resistance to fading of dyed silk when exposed to Xenon arc fading lamp light was
measured using ISO- 105/ B02 method by exposing the half portion of the sample for 20 hours.
Test Procedure
The silk sample is cut according to the temple size and attached to the temple in a half covered
manner along with standard dyed wool. The samples are then mounted on light fastness tester.
Time and light is set. Half portion of the sample is exposed to Xenon arc fading lamp light for
20 hours. Finally, sample is taken out.
Evaluating is done with Blue scale with a rating of 1-8.
3.6.2 Shade performance measurement
Using data color, in this project, we have measured Absorption value (K/S) of 15 acid dyed
silk samples and 15 basic dyed silk sample.
3.7 Conclusion
This project work is done by two dyeing processes for silk fabric using acid and basic dyes
with suitable chemical and auxiliaries, equipment. Silk dyeing with basic dyes is not yet a
widely used method. For this enough information about silk dyeing with basic dyes is not
found. But tried to use the best method, materials and procedure for silk dyeing with both dyes.
Basic dyes can also be used for silk dyeing if the fastness properties can be increased by
mordanting.

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Chapter 4: Results and Data
4.1 Introduction
In this chapter we have discussed about the result and output in details. This is very important
for any type of work because of getting the overview of the work from this section. In this work
the result and data are shown perfectly and smoothly so that the output can be realized easily.
Every point of this output is given importance. The prime focus of this chapter is to evaluate
color strength, colorfastness and costing of acid and basic dyed silk sample. For evaluation the
result of data and image of sample for every process, color strength, color fastness and costing
is added.
4.2 Data on color strength
a) 0.5% b) 1% c) 2% d) 3% e) 4%
Fig 4.1 k/s value of acid dyed silk sample (red)
a) 0.5% b) 1% c) 2% d) 3% e) 4%
Fig 4.2 k/s value of basic dyed silk sample (red)
k/s value from fig 4.1 and fig 4.2 is used in table 4.1

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Table 4.1 Comparison of K/S value of acid and basic dyed silk samples (Red shade)
Red
K/S value (630 nm)
0.5% conc.
(owf)
1% conc.
(owf)
2% conc.
(owf)
3% conc.
(owf)
4% conc.
(owf)
Acid dye 1.61 2.97 5.99 9.52 11.45
Basic dye 1.41 2.13 3.71 6.48 8.15
a) 0.5% b) 1% c) 2% d) 3% e) 4%
Fig 4.3 k/s value of acid dyed silk sample (Blue shade)
a) 0.5% b) 1% c) 2% d) 3% e) 4%
Fig 4.4 k/s value of basic dyed silk sample (blue)
Table 4.2 Comparison of K/S value of acid and basic dyed silk samples (Blue shade)
Blue
K/S value (630 nm)
0.5% conc.
(owf)
1% conc.
(owf)
2% conc.
(owf)
3% conc.
(owf)
4% conc.
(owf)
Acid dye 1.21 2.18 4.45 6.85 8.93
Basic dye 9.23 15.35 19.66 21.33 20.89

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a) 0.5% b) 1% c) 2% d) 3% e) 4%
Fig 4.5 k/s value of acid dyed silk sample (Yellow shade)
a) 0.5% b) 1% c) 2% d) 3% e) 4%
Fig 4.6 k/s value of acid dyed silk sample (Yellow shade
Table 4.3 Comparison of K/S value of acid and basic dyed silk samples (Yellow shade)
Yellow
K/S value (440 nm)
0.5% conc.
(owf)
0.5% conc.
(owf)
0.5% conc.
(owf)
0.5% conc.
(owf)
0.5% conc.
(owf)
Acid dye 1.68 1.68 1.68 1.68 1.68
Basic dye 5.08 7.89 13.59 19.7 18.58

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4.3 Result on Color fastness
4.3.1 Color fastness to light
Table 4.4 Color fastness to light for acid and basic dyed silk fabric (Red shade)

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Table 4.5 Color fastness to light for acid and basic dyed silk fabric (Blue shade)
Table 4.4 and 4.5 shows that light fastness for red and blue shade is average-good for acid dyes
and moderate for basic dyes.

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Table 4.6 Color fastness to light for acid and basic dyed silk fabric (Yellow shade)
Table 4.6 shows that light fastness for yellow shade is good for acid dyes and average for basic
dyes.

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4.3.2 Color fastness to Washing
(Red 0.50%)
(Red 1.00%)
(Red 2.00%)
(Red 3.00%)

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(Red 4.00%)
(Red 2.00%)
(Red 0.50%)
(Red 1.00%)
Fig 4.7 Color fastness to light for acid dyed silk fabric (Red shade)
Fig 4.7 shows that wash fastness for acid dye red shade is moderate-average.

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(Red 4.00%)
(Red 3.00%)
(Blue 0.50%)
(Blue 1.00%)
Fig 4.8 Color fastness to light for basic dyed silk fabric (Red shade)
Fig 4.8 shows that wash fastness for basic dye red shade is poor-moderate.

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(Blue 4.00%)
(Blue 3.00%)
(Blue 2.00%)
Fig 4.9 Color fastness to light for acid dyed silk fabric (Blue shade)
Fig 4.9 shows that wash fastness for acid dye blue shade is good.

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(Blue 3.00%)
(Blue 2.00%)
(Blue 1.00%)
(Blue 0.50%)

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(Blue 4.00%)
(Yellow 2.00%)
(Yellow 1.00%)
(Yellow 0.50%)
Fig 4.10 Color fastness to light for basic dyed silk fabric (Blue shade)
Fig 4.10 shows that wash fastness for basic dye blue shade is poor-moderate.

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(Yellow 4.00%)
(Yellow 3.00%)
(Yellow 1.00%)
(Yellow 0.50%)
Fig 4.11 Color fastness to light for acid dyed silk fabric (Yellow shade)
Fig 4.11 shows that wash fastness for acid dye yellow shade is good-excellent.

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(Yellow 3.00%)
(Yellow 2.00%)
(Yellow 4.00%)
Fig 4.12 Color fastness to light for Basic dyed silk fabric (Yellow shade)
Fig 4.12 shows that wash fastness for basic dye yellow shade is average-good.

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4.3.3 Color fastness to rubbing
Acid dyed red sample 2.00% shade

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Fig 4.13 Color fastness to rubbing(staining) for acid dyed silk fabric (Red shade)
Fig 4.13 shows that dry rub fastness for acid dye red shade is excellent and wet rub fastness is
good-excellent.
Basic dyed red sample 2.00% shade

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Fig 4.14 Color fastness to rubbing (staining) for Basic dyed silk fabric (Red shade)
Fig 4.13 shows that dry rub fastness for basic dye red shade is excellent and wet rub fastness
is good.
Acid dyed blue sample 0.50% shade

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Fig 4.15 Color fastness to rubbing(staining) for acid dyed silk fabric (blue shade)
Fig 4.15 shows that dry rub fastness for acid dye blue shade is excellent and wet rub fastness
is good-excellent.
Basic dyed blue sample 0.50% shade

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Fig 4.16 Color fastness to rubbing(staining) for basic dyed silk fabric (Blue shade)
Color fastness to rubbing (Basic dyed blue sample 1.00% shade)

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Fig 4.16 shows that dry rub fastness for basic dye blue shade is average-good and wet rub
fastness is moderate-average.
Acid dyed yellow sample 0.50% shade

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Fig 4.17 Color fastness to rubbing (staining) for acid dyed silk fabric (Yellow shade)
Fig 4.13 shows that dry and wet rub fastness for acid dye yellow shade is excellent.
Basic dyed yellow sample 0.50% shade

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Fig 4.18 Color fastness to rubbing(staining) for basic dyed silk fabric (Yellow shade)
Fig 4.18 shows that dry rub fastness for basic dye yellow shade is excellent and wet rub
fastness is good-excellent.

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4.3.4 Color fastness to Perspiration
Acid dyed red sample for 0.50% shade

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Fig 4.19 Color fastness to perspiration for acid dyed silk fabric (Red shade)
Fig 4.19 shows that fastness to perspiration for acid dye red shade is excellent.
Basic dyed red sample for 0.50% shade

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Fig 4.20 Color fastness to perspiration for Basic dyed silk fabric (Red shade)
Fig 4.20 shows that fastness to perspiration for basic dye red shade is good-excellent.

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Acid dyed blue sample for 1.00% shade

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Fig 4.21 Color fastness to perspiration for acid dyed silk fabric (Blue shade)
Fig 4.21 shows that fastness to perspiration for acid dye blue shade is excellent.
Basic dyed blue sample for 0.50% shade

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Fig 4.22 Color fastness to perspiration for Basic dyed silk fabric (Blue shade)
Fig 4.22 shows that fastness to perspiration for basic dye blue shade is average-excellent for
acidic condition and excellent for alkaline condition

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Acid dyed yellow sample for 0.50% shade

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Fig 4.23 Color fastness to perspiration for acid dyed silk fabric (Yellow shade)
Fig 4.23 shows that fastness to perspiration for acid dye yellow shade is excellent.
Basic dyed yellow sample for 0.50% shade

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Fig 4.24 Color fastness to perspiration for basic dyed silk fabric (Yellow shade)
Fig 4.23 shows that fastness to perspiration for basic dye yellow shade is excellent.

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4.4 Costing
4.4.1 Costing for silk dyeing acid ayes (Red, Blue, yellow shade)
In the silk dyeing with Acid Dyes, stock solution for Acid Dyes is 1%, sample weight is 4gm,
leveling agent is 1% & stock solution is 10%, Buffer is 1 g/l & stock solution is 10%. For
dyeing M: L is 1:10 but for after treatment M: L is 1:20.
For 0.5% shade-
Ingredient Quantity (gm) Rate of Price (per /kg) Cost(USD)
Acid Dyes 0.02 USD 20 (20×78=1560tk) 0.0004
Levelling Agent (Albagal Set) 0.04 USD 4.50 (4.50×78=351tk) 0.00018
Buffer (Albatex AB 45) 0.1 USD 2.20 (2.20×78=171.6tk) 0.00022
Soaping Agent (Eriopon OS) 0.08 USD 4.50 (4.50×78=351tk) 0.00036
Fixing Agent (Erional FRN) 1.2 USD 4.50 (4.50×78=351tk) 0.0054
Total 0.00656
For 1.00 % shade-
Acid Dyes 0.04 USD 20(20×78=1560tk) 0.0008
Levelling Agent (Albagal Set) 0.04 USD 4.50(4.50×78=351tk) 0.00018
Buffer (Albatex AB 45) 0.1 USD 2.20(2.20×78=171.6tk) 0.00022
Soaping Agent (Eriopon OS) 0.08 USD 4.50(4.50×78=351tk) 0.00036
Fixing Agent (Erional FRN) 1.2 USD 4.50(4.50×78=351tk) 0.0054
Total 0.00696

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For 2.00 % shade-
Acid Dyes 0.08 USD 20(20×78=1560tk) 0.0016
Total 0.00776
For 3.00 % shade-
Acid Dyes 0.12 USD 20(20×78=1560tk) 0.0024
Total 0.00856
For 4.00 % shade-
Acid Dyes 0.16 USD 20(20×78=1560tk) 0.0032
Total 0.00936

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4.4.2 Silk Dyeing with basic dyes (Red, Blue, yellow shade)
In the silk dyeing with Basic Dyes, stock solution = 1%, sample weight = 4gm, Levelling agent
=1g/l& stock solution=10%, Glauber salt =10g/l & stock solution=20%, and for dyeing M: L
= 1:10 but for after treatment M: L=1:20.
For 0.50 % shade-
Ingredient Quantity (gm) Rate of Price (per /kg) Cost
Basic Dyes 0.02 USD 20(20×78=1560tk) 0.0004
Glauber salt 0.02 USD 2.20(2.20×78=171.6tk) 0.000044
Acetic Acid 0.12 USD 4.50(4.50×78=351tk) 0.00054
Total 0.001524
For 1.00 % shade-
Basic Dyes 0.04 USD 20(20×78=1560tk) 0.0008
Total 0.001924

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For 2.00 % shade-
Basic Dyes 0.08 USD 20(20×78=1560tk) 0.0016
Total 0.002724
For 3.00 % shade-
Basic Dyes 0.12 USD 20(20×78=1560tk) 0.0024
Total 0.003524
For 4.00 % shade-
Basic Dyes 0.16 USD 20(20×78=1560tk) 0.0032
Total 0.004324

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4.5 Conclusion
The project work is done to get best result in this project for silk dyeing with acid and basic
dyes. The result is based on comparison of cost effectiveness of two dyes and for this showed
the color strength and color fastness test results by using image of sample with suitable size.
As a result, it could be able to indicate the suitable dyes for silk dyeing both from the point of
view of cost and effectiveness. This project work is done for small amount of samples so
costing is calculated here for 4 g sample but in next chapter discussed the costing for per kg of
silk.

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Chapter 5: Discussion
5.1 Introduction
This is the chapter where given importance on discussion based on the result of the project
what are done. Discussion is very essential as what is output known by this part. Comparing
criteria of this project work are shade strength, color fastness properties and last one is costing
between acid and basic dyed silk fabric. The final output of this project based on these three
criteria is discussed in this chapter. The shade strength and color fastness results are discussed
by using chart so that can be easily compare among both dyes and their performances.
5.2 Comparison on the basis of color strength
Fig. 5.1 Bar diagram of K/S value of acid and basic dyed silk samples (Red shade)
Figure 5.1 shows the effect of dye concentration on dye uptake. Dye uptake increased
progressively as colorant concentration increased. With increasing concentration, more dye
transferred to fabric and the depth of color became stronger. From the above bar diagram, it is
clear that the acid dyes show higher dye take-up than basic dyes at higher dye concentrations
for red color.
0
2
4
6
8
10
12
14
0.50% 1% 2% 3% 4%
Effect of dye concentration on dye take up (Red)
Acid dye Basic dye

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Fig. 5.2. Bar diagram of K/S value of acid and basic dyed silk samples (Blue shade)
clear that the basic dyes show higher dye take-up than acid dyes at higher dye concentrations
for blue color.
Fig. 5.3 Bar diagram of K/S value of acid and basic dyed silk samples (Yellow shade)
0
5
10
15
20
25
0.50% 1% 2% 3% 4%
Effect of dye concentration on dye take up (Blue)
Acid dye Basic dye
0
5
10
15
20
25
0.50% 1% 2% 3% 4%
Effect of dye concentration on dye take up (Yellow)
Acid dye Basic dye

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clear that the basic dyes show higher dye take-up than acid dyes at higher dye concentrations
for yellow color.
5.3 Comparison on the basis of color fastness
Fig 5.4 Color fastness to light (Blue scale value)
From the fig 5.4 it is found that, acid dyed silk sample shows better color fastness to light than
basic dyed silk. It is also visible that fastness to yellow color for basic dyes is comparatively
better than red and blue color for basic dyes.
0
1
2
3
4
5
6
Red Blue Yellow
Acid Dye
Basic Dye

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Fig 5.5 Color Fastness to Washing (Grey scale value for color change)
From figure 5.5, it is clear that, acid dyed silk sample shows better resistance color fading
against the action of washing. It is also visible that fastness to yellow color for basic dyes is
comparatively better than red and blue color for basic dyes.
Fig 5.6 Color Fastness to Washing (Grey scale value for staining)
From figure 5.6, it is noticed that, acid dyed silk sample shows slightly better performance in
case of staining than basic dyed silk during washing (for red color).
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Red Blue Yellow
Acid Dyes
Basic Dyes
0
1
2
3
4
5
6
Acetate Cotton Polyamide Polyester Acrylic Wool
Acid Dyes (Red)
Basic Dyes (Red)

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From figure 5.7, it is noticed that, acid dyed silk sample shows very much better performance
in case of staining than basic dyed silk during washing (for blue color).
From figure 5.8, it is noticed that, acid dyed silk sample shows much better performance in
case of staining than basic dyed silk during washing (for blue color).
0
1
2
3
4
5
6
Acid Dyes (Blue)
Basic Dyes (Blue)
0
1
2
3
4
5
6
Acid Dyes
(Yellow)

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Fig 5.9 Color Fastness to Rubbing (Grey scale value for dry rub)
Figure 5.9 represents that, staining performance of acid dyed silk is almost same as the basic
dyed silk fabric in case of red and yellow shade for dry rubbing while in case of blue shade,
staining performance of acid dyed silk is comparatively better than basic dyed silk.
Fig 5.10 Color Fastness to Rubbing (Grey scale value for wet rub)
Figure 5.10 represents that, staining performance of acid dyed silk is better than the basic dyed
silk fabric in case of wet rubbing.
0
1
2
3
4
5
6
Red Blue Yellow
Acid Dyes
Basic Dyes
0
1
2
3
4
5
6
Red Blue Yellow
Acid Dyes
Basic Dyes

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Fig 5.11 Color Fastness to Perspiration (Grey scale value (color change) for acidic solution)
Figure 5.11 represents that, resistance to color fading against the action of acidic perspiration
of acid dyed silk is much better than the basic dyed silk fabric in case of red and blue shade
while in case of yellow shade, color fastness of acid dyed silk is almost same as the basic dyed
silk.
Fig 5.12 Color Fastness to Perspiration (Grey scale value (color change) for alkaline solution)
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
5
5.1
Red Blue Yellow
Acid Dyes
Basic Dyes
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
5
5.1
Red Blue Yellow
Acid Dyes
Basic Dyes

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Figure 5.12 represents that, resistance to color fading against the action of alkaline perspiration
of acid dyed silk is much better than the basic dyed silk fabric in case of red shade while in
case of blue and yellow shade, color fastness of acid dyed silk is almost same as the basic dyed
silk.
Fig 5.13 Color Fastness to Perspiration (Grey scale value (color staining) for acidic solution)
Figure 5.13 represents that, staining performance of acid dyed silk is very much better than the
basic dyed silk fabric in case of acidic perspiration.
0
1
2
3
4
5
6
Red Blue Yellow
Acid Dyes
Basic Dyes

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Fig 5.14 Color Fastness to perspiration (Grey scale value (color staining) for alkaline
solution)
Figure 5.14 represents that, staining performance of acid dyed silk is very much better than the
basic dyed silk fabric in case of acidic perspiration.
5.4 Comparison on the basis of costing
Fig 5.15 Total cost in USD for 1kg silk fabric dyeing
0
1
2
3
4
5
6
Red Blue Yellow
Acid Dyes
Basic Dyes
0
0.5
1
1.5
2
2.5
0.50% 1.00% 2.00% 3.00% 4.00%
Acid Dyes
Basic Dyes

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Table 5.1 Costing for 1kg silk fabric dyeing by acid and basic dyes
The above data represents that silk dyeing with acid dyes is costlier than dyeing with basic
dyes. One of the main reason behind this is the use of fixing agent during silk dyeing with acid
dyes while no fixing agent is used in case of basic dye as it was recommended by basic dyes
suppliers. It is also clear that the cost increases with the increase of dye concentration.
5.6 Comparison on basis of all parameters
For the ease of understanding all the results and assessments are summarized below:
Parameters Comparison
Dye uptake
Acid dyes show higher dye take up than basic
dyes in case of red shade but basic dye shows
higher dye take up in case of blue and yellow
shade.
Light Fastness (ISO-105/B02)
Acid dyes show better performance than basic
dyes.
Wash fastness Test (ISO-105/C06-C2S)
 Color Change
 Color Staining
Acid dyes show better performance than basic
dyes.
Dyes
Total cost in USD for 1 kg fabric dyeing
0.5% conc.
(owf)
1% conc.
(owf)
2% conc.
(owf)
3% conc.
(owf)
4% conc.
(owf)
Acid dye
(Red, Blue, Yellow)
1.64 1.74 1.94 2.14 2.34
Basic dye
(Red, Blue, Yellow)
0.381 0.481 0.681 0.881 1.081

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Rubbing Test (ISO-105 X12)
Both acid and basic dyes show better
performance though acid dye shows slightly
better performance than basic dye.
Perspiration Test (ISO-105/E04)
 Color change
 Color staining
Both acid and basic dyes show better
performance in case of fading but for staining
acid dye’s performance is better.
Cost
Dyeing with basic dye is economical than acid
dye as cost of basic dyes are less.
5.7 Conclusion
In this chapter the output of the research is clearly shown by bar diagram for every dyes, shade
percentage and for color fastness to washing, rubbing, perspiration. From these bar diagram
finds out that basic dyeing cost is less but the fastness properties of acid dyes are good. So as
the fastness properties are very important for dyeing, acid dyes are suitable for silk dyeing in
overall point of view.

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Chapter 6: Conclusion
6.1 General conclusion
This project work is done to find out suitable cost effective dyes for dyeing silk among acid
dyes and basic dyes. During this project work silk is dyed with three different color (red, blue,
yellow) for 5 shade (0.5%, 1%, 2%, 3 %, 4%). Then color strength value is taken by Data Color
and fastness tests (light, wash, rubbing, perspiration) are done to compare the dyeing
performance and find out the result of the project. It is found that acid dyes show higher dye
uptake for red shade while basic dyes show better dye uptake for blue and yellow shade. Color
fastness tests on silk for acid dyes generally show better performance but in case of color
fastness to rubbing and perspiration tests both dyes show similar result. Dyeing with basic dyes
is comparatively economical than acid dyes as basic dyes are cheaper. As fastness properties
are given priority for fabric dyeing, in this case acid dyes are more suitable for silk dyeing.
6.2 Recommendation
 The project work suggests that silk dyeing with acid dyes is more suitable from the
point of view of fastness properties and dye uptake as the data shows good result for
acid dyes.
 On the other hand, basic dyes are suitable from economical point of view as basic dyes
cost is less than acid dyes.
 The fastness properties of basic dyes can be increased by mordanting in further
research.
 In future apply basic dye along with acid dye can be applied through vigorous research
and process development.
6.3 Limitations
 Silk dyeing with basic dyes is not yet widely used method. For this enough information
about silk dyeing with basic dyes is not found.
 As the project work is done in sample dyeing process, the solution amount was very
little so it was difficult to maintain the perfect amount of chemical solution.

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 It was critical to maintain exact pH during the dyeing process for both acid dyes and
basic dyes.
 Sometimes dye powder did not mix uniformly, that’s why experienced some dyeing
spots on fabric and rejected those.
 The dyes were collected from two different companies, for this there is some shade
matching problem of same color dyes.
 In case of color fastness to rubbing test, cotton rubbing cloth is not suitable for silk
rubbing. So rubbing result is not accurate.
 The samples are dried in normal dryer instead of stenter. Use of stenter may further
increase the performance.

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References
[1] J. Gordon Cook, Handbook of textile fibres.
[2] Md. Koushic Uddin, A comparative study on silk dyeing with acid dye and reactive dye ,
Journal of IJET
[3] Textile Testing Laboratory, CSTRI, Central Silk Board, Varanasi.
[4] http://www.natursint.com/SILKSKIN_PRESENTATION.pdf
[5] http://www.slideshare.net/YousufTE/natural-textile-fibers-cotton-jute-silk-wool
[6] https://www.tes.com/lessons/xgx8VfOSYlkF4w/silk-fibroin
[7] http://www.silkfabric.info/history/history-of-silk.html
[8] http://textilelearner.blogspot.com/2011/08/characteristics-of-silk-fabrics_5368.html
[9] http://www.yourarticlelibrary.com/zoology/silk-properties-and-uses-of-silk/23816/
[10] Bangladesh Textile Today Blog
[11] WWW.Wikipedia.com/acid dye
[12] A D Broadbent(2001), Basic principles of textile coloration.
[13] E R Trotman, Dyeing and chemical technology of textile fibre.
[14] Introduction to the physical basis and measurement of color .
[15] http://textilelearner.blogspot.com/2011/07/bleaching-process-of-silk-
silk.html#ixzz3voYqBCdU

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