leveling agents chemistry and performance
TRANSCRIPT
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
Home / Cover Story / Leveling agents: chemistry and performance
Leveling agents: chemistry andperformanceProf S.K. Laga, Miss Rashmi Joshi.M and Mr. Vignesh DhanabalanD.K.T.E.S Textile & Engineering Institute, Ichalkaranji-416115(M.H), India. E-mail: [email protected] , [email protected],
Issue » February, 2014 Volume 07, Issue 02 Print this News
Abstract
The appeal (comfort) of the fabric material is a main parameter that decides themarket flow of the product. To bring in complicated design and trendy material,
Current Issue
Home Cover Story Top Story Business Today In Focus Technical Article Advertorial
Technology Today Face to Face
Search this site SearchAbout Us Executive Panels Authors Guideline Advertisement Contact
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
shade variations have always been a hurdle. It remains so as, the dye uptake andfixation and of the dye material is random. Leveling agent are chemical agentsthat work on the dye molecule and help in fixing the dye particles uniformly. Inthis paper we have made efforts to share the knowledge on what leveling agentsand dispersing agents are, the necessity of leveling agent, different classes ofleveling agent, their testing methods and some means of synthesizing levelingagents for industry and laboratory use.
Keywords: Colloidal particle, color tone, dispersing agent, dye uptake, levelingagents.
Introduction
Dyeing and printing are processes of imparting color onto the substrate. Thisimparting of color is done by use of wet and dry processing techniques. In wetprocessing, substrate comes in contact with the dye solution and coloring takesplace. Due to various reasons like surface tension, unevenness, capillary action,polar component and other parameters, the uniform dyeing gets affected. Toyield color in wet processing in a better manner, chemical Auxiliaries are used.One such kind is leveling agent and the other is dispersing agent. Dispersingagents are substances that promote the more or less uniform and stablesuspension of relatively small particle in a given matrix. The function ofdispersing agent is to prevent agglomeration of individual dye particle duringdyeing. They play a subsidiary role in dispersion involving in textile coloration.Dispersing agents are much preferred for Vat dyeing, Disperse dye and pigmentpadding. The anionic product ionizes water and form an electrical double layer.The mutual repulsion between these groups keep dye particle apart and preventagglomeration
Many fabrics during dyeing have high initial dye uptake causing unevenness orshade variation. Leveling agents are added to the dye bath to regulate the
Subscribe for PrintedMagazine »
Newsletter Subscription
unsubscribe
Subscribe
Join Our Community
Bangladesh Textile Today3,812 likes
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
process of dyeing to obtain uniform shade throughout the substrate. Levelingagents are soluble in water but, the solubility reduces with increase intemperature and finally becomes insoluble after a temperature called as thecloud point. On selection of leveling agent the cloud point temperature of theleveling agent is an important parameter.
Level dyeing can be broadly classified into two categories
Gross unlevelness throughout the material : The substrate is uniformthroughout both physically and chemicallyLocalized unlevelness: Non uniformity of substrate (either wise).
Unlevelness, bareness or patchy dyeing occurs during dyeing due to
deformity in fibre/yarn, fabric structure,Improper dyeing process or condition,Improper selection of dyestuffs for dyeing.
Difference between leveling and dispersing agent:
Dispersing agents are known to improve the migration and leveling of dispersedye on polyester during HT dyeing.
Leveling agent tend to slow down the dye uptake of the fibers helping to producemore uniform color in the textile fiber. They are also termed as retarding agentsor retarders. The use of retarders is essential in situation in which dye tends torush on to the fiber and results in unevenly colored textile material. Levelingagents are surface active agents and are chemically related to soaps, syntheticdetergents and wetting agents. They may be anionic, cationic or non-ionicorganic compounds.
V is it Us
Be the first of your friends to like this
Like Page Share
Interest Groups
Education & Innovation
Value Chain & Trade
Fashion & Clothing
Dyeing & Finishing
Fabric, Weaving & Knitting
Yarn & Spinning
Fiber & Polymer
Technical Textiles
++
Read More »
Overcoming metal problems inthe reactive dyeing of cellulose
Updates from world’s textileindustry
Merchandising from Factoriesto buying houses
++
Many buyers cancelledvisiting Dhaka: Unexpected
travel- cost and hassle for RMGmarketing
Professional office mannerand etiquette: The reflection
of any company's value, image &culture
++
Fashion merchandising:functions of productionmerchandiser
Introduction to fashionmerchandising
++
Overcoming metal problems inthe reactive dyeing of cellulose
Merchandising from Factoriesto buying houses
++
Formulating equation tocalculate 'fibre percentages' inweft knitted fabric
++
Air-jet yarn texturing and itsnozzles
++
Air-jet yarn texturing and its++
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
Effect of leveling agents:
Specific leveling agents, that can be either no-ionic or anionic surfactants orcompounds, increase the solubility of the dye, thereby lowering the initial strikeand overall rate of the dye uptake which can also cause a restraining effectresulting in a loss of color yield. The solubility of the leveling agent decreaseswith increasing temperature, and if, the temperature of the bath increases abovethe cloud point of the agent then the dye dispersion takes place resulting in dyeaggregation and attendant of unlevel dyeing.
Herlinger et al proposed that at concentration above CMC, non-ionic agentslower the dye uptake owing to a corresponding increase in solubility of the dye,this reduction increases with increase in solubility of the dye. Anionic agentsincrease the cloud point of the non-ionic leveling agents. Careful considerationmust be given to the amount of non-ionic leveling agent used owing to the oftenmarked restraining effect exerted by the compound on dye uptake. [1-3]
Table 1: Commercially available leveling agents
Trade Name Nature Manufacturer
Supersol VL SuperChem.
Non-ionic (for PET, vat dyes)
Dispersol K paste Anionic ICI, India
Deterzol D Paste Anionic fatty alcoholsulphate
Associated Enterprise
Dispersol VLH Non-ionic ICI, India
Read More »
Read More »
Bangladesh garment exportsoars though disaster cloudsthe country
Read More »
Fashion merchandising :sourcing
Read More »
A case history in right-first-time (RFT) dyeing
Read More »
Knitting Corrugated Yarn-Technical Requirements
Analysis
Recycling technology by VTT :Converting paper &
cardboard into biodegradablenonwovens
Read More »
Global Cotton Summit 2015:Critical analysis of ICA rules,
bylaws and their implications onBangladeshi cotton importers
Moisture mobility in texturedyarns and fabrics
Read More »
Air-jet yarn texturing and itsnozzles
We need to establish someginning factory in various
countries from where we areimporting cotton
Read More »
Many buyers cancelledvisiting Dhaka: Unexpected
travel- cost and hassle for RMGmarketing
Waterproof breathablefabrics: Technologies and
practices
Top notch needles and threadsfor technical textiles
Archive Issues
View All Issues »
2008 2009 2010 2011 2012
2013 2014 2015
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
Lyogen DK Wool, Silk and Nylon Sandoz (I)
Lyogen SMK For wool, silk, nylon Sandoz (I)
Tenegal CVN (liquid) Anionic Suhred Geigy Co.
Polylevel SG Non-ionic (for wool) Suhred Geigy Co.
Tenegal CVN (liquid) Anionic (for nylon) Suhred Geigy Co.
Lyogen DFT Non-ionic for PET &blends
Sandoz (I)
Types (or) classification of leveling agents:
Leveling agents are classified into two main groups based on ionization andstructure wise
1. According to the ionic nature
AnionicCationicNon-ionic [used for PET dyes]
Anionic agent:
The molecules of these compounds consist of largely negative charged or anionicorganic radical. When anionic agents are added to the dye liquor, the anionicagents will be attracted to any positive sites of the fiber. The anionic agents try torepel similarly charged anionic dye molecules. As the bath is heated themolecules develop sufficient energy to overcome the repulsive forces between
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
the retarder and the dye. These anionic agents tend to give more uniform dyeuptake of the fiber.
Cationic agents:
The molecules of these compounds consist of largely positively charged orcationic organic radical. When cationic agents are added to the dye liquor, theircaptions are attracted to the anionic dye molecule. This neutralizes the electricalcharge of the dye molecule and minimizes the substantively of the fibers. Theenergy provided by heating cause the cationic radicals of the leveling agent togradually dissociate of the cationic agent from the anionic dye molecule slowlyreleases the dye and ensures a more uniform absorption of the polymer systemof the fiber.
Anionic Leveling agents -> silk, wool, nylon, Bast.Cationic leveling agents -> wool, silk, acrylic, nylon, cellulosicNon-ionic -> synthetics & blends
2. According to the chemical structure
Fatty Acid (Ethylene Urea)Fatty alcohol (Sulphates)Sulphated (Fatty amine)Alkyl aryl (Sulphonates)Fatty alcohol ethylene (oxide condensate)
Mechanism of functioning of leveling agents:
The two fundamental mechanisms that contribute to level dyeing are
Control of exhaustion of dye so that it is taken up evenly
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
Migration of dye after initial unlevel sorption on the fiber.
The attractive force between agent and dye create a counter balancingmechanism against fiber-dye attractive forces, restraining the uptake of the dyeby the fiber. As the temperature increases the complex gradually breaks down,progressively releasing the dye for more gradual sorption by the fiber, thisclearly shows leveling agent working by this mechanism that rely on theattractive force between the fiber and the dye particle but, similarly strong forceof attraction may result in a complex that is difficult to break down.
Leveling agent (a) allows the dye to get in to the fiber regardless of initialUnevenness. During the course of further dyeing levelness is achieved throughmigration. For this selection of dyes for dyeing is of utmost importance or (b) itcontrols/retards the rate of dyeing throughout the dyeing cycle. Sometimes theleveling agent acts in both the ways.
Some mechanisms are stated below:
Non-ionic leveling agents are used in direct dyeing. They promote leveling bybreaking the dye aggregates that migrate slowly.The action of a non-ionic surfactant in reducing the uptake of dye by wooland silk is based on the formation of a complex between the dye and thesurfactant; it reduces the effective concentration of dye, i.e. the complex actsas a reservoir from which dye is gradually released on heating owing todecomposition of the complex.Leveling agent selected for vat dyeing must give the required initialretardation without a significant loss in color yield. Leuco vat dyes havegreater affinity to absorption, which causes unlevel dyeing. The two mostwidely used types of Leveling agents for Vat dyes are cationic activesurfactants and non-ionic ethylene oxide condensate. The cation activeproducts compete with the leuco vat dye for available sites in the fibre and
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
thus retard the dyeing process. The retarder-dye complex acts as a reservoirfor the leuco vat dye preventing from dye rushing to the fibre in the initialstages. The complex breaks so that, the dye is slowly released during thelater stage of dyeing.In case of dyeing nylon with 1:2 metal complex dye, due to poor migration ofdyes unlevel dyeing is obtained. Non-ionic Leveling agents have affinity forthese dyes hence; they retard the exhaustion and produce level dyeing.If a mixture of mono-sulphonic and trisulphonic acid is used in dyeing ofnylon to produce compound shades, the mono sulphonic acid dye will befirst taken by the fibre and will turn black for the polysulphonic dye. Here,anionic Leveling agents will complete with monosulphonic acid dyes foravailable sites in the fiber and thus it will minimize the blocking effect andproduce level dyeing.
Table 2: Use of leveling agents based on ion type
Ion type Fiber type Dye
Non-Ionic/Anionic Cotton, Wool,Nylon, Polyester
Azoic, Vat, Directmilling, Metal Complex,Disperse
Nonionic/Cationic Wool, Nylon,Polyester
Direct milling, MetalComplex, Disperse
Anionic Wool Acid, Mordant, MetalComplex, Reactant
Weakly Anionic Cotton, Wool,Nylon, Polyester
Acid, Direct, Disperse
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
Anionic/Cationic Polyester Acid, Metal-Complex
Cationic Wool, Nylon, Basic, Acid, Metal-Complex, Reactive
Weakly cationic Acrylic, Wool,Nylon,
Acid, Mordant, Metal-Complex
Cationic/Polymeric Cotton Vat, Sulphur
Amphoteric Wool Acid, Mordrant, Metal-Complex, Reactive
Testing method for evaluation of efficiency of leveling agent:
(a) By Performance Test
Carry out separate dyeing with and without pressure of leveling agent with bluedyes (which would be easier to plot the blot marks). Then, compare the levelnessof both the samples. Choose any class of blue dye having poor Levelingproperties.
Concentration of Leveling agent = Max. 5 gpl.
Fig 1: optimum concentration to exhaustion rate
Higher the concentration higher will be leveling effect but after certain level theattraction force becomes very high that it is difficult to break down. Byincorporating certain chemicals in the dyeing liquor we can overcome one or
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
more causes of non-uniformity.
(b) By determining active content
To determine the active content of the material prepare a solution of 20 mlLeveling agent sample in 100 ml graduated measuring cylinder and add 20 ml 2N sulfuric acid to it. Place the measuring cylinder in water bath at 60 0C for 2 hrsand then cool it. Observe the height of the oil layer after cooling.The active content can be calculated using the following relationship
V2 Active Content = ———— x 100 % V1Where, V1 = Volume of Sample taken.V2 = Volume of Oil Layer.
(c) By determining the strike percentage
The Strike (S) is defined as the color on 1 min sample expressed as % of the coloron the one hour sample.
To determine the strike percentagePrepare a small fabric sample measuring 2 x2 cm and another large fabric sample measuring 10 cm x 10 cm and a solution of(0.1 %) Foron Blue SE2RI 200%.
Prepare the dye-bath using the above dye solution keeping material to liquorratio 1: 50 and add 2 gm/liter leveling agent to this dye-bath. Dip the sample inthe dye bath and increase the temperature to 80 0C. Remove small sample afterone minute and the large sample after an hour. Measure the reflectance for boththe using spectrophotometer.
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
To calculate the strike % using the following relationship
( R0 – R1 )S = —————– x 100( R0 – R60 )
Where, R0 = Total reflectance on undyed sample, R1 = Total reflectance on 1 minsample.
R60 = Total reflectance on 60 min sample.
Efficiency of leveling agent:
Table 3: Test results conducted by ATIRA on different grades of dye with varyingconcentrations of leveling agent
Trials were conducted by ATIRA to determine the effect of dye absorption byleveling agent. Various dyes were used at concentrations between 0.5 to 2.0 g/l ofwater and concentrations of leveling agents at 0.25, 0.5, 1.0, 1.5, 2.0 g/l. Dyedmaterial without use of leveling agent were kept as 100% and the test wasconducted, it was found that leveling agents gave good distribution results up to0.5 g/l followed by depreciation in the color yield. This loss in effect may be dueto more energy required to break the attraction force between the fiber-dyesolutions.
Root causes for uneven / unlevel dyeing:
Improper dye dissolution.Too much affinity of dye towards substrate.
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
Role of leveling agent in dyeing:
The leveling agent will compete with the dyes having affinity towards substrate. HLB value of leveling agent is higher than that of dispersing agent. For Syntheticand its blends, generally non-ionic leveling agents are used that can withstandhigher temp of dyeing, Say 1300C. These are the condensates of ethylene oxideand higher fatty alcohol, fatty amines.
General Preparation of Leveling Agents
The category of chemical used for preparation of leveling agent has been shownbelow with an example is illustrated below
Example
Fatty alcohol Sulphates :
Lauryl alcohol and oleum on sulphation at 1.5 atm. pressure. The Sulphatedproduct is further alkali fused. The product is chemically identical to commercialproduct (Gardinal WA). It can be used as leveling agent for dyeing nylon with aciddyes.
Sulphated fatty amines:
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
The final product has same chemical composition as the commercial productEMCOL. It can be used for dyeing of wool, silk with acid colors.
Fatty acid ethylene Urea Product :General prepration
Example
The final product has same chemical composition as the commercial productLyogen SMK. It is used for dyeing of wool with neutral acid dyes.
Alkyl naphthalene Sulphonate :
The final product is a non-ionic alkyl naphthalene sulphonate which haschemical components similar to Lyogen DFT used as leveling agent in dispersesdyeing.
Commercial Method for preparation of Alkyl naphthalene Sulphonate
In industry first sulphonation is carried out. Then, methylation is done and lastlyalkali fusion.
First step (1600C / 1-2 hrs.) with
Naphthalene = 190 – 200 kg.
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
98% H2SO4 = 1900 – 2000 liters.
2nd Step: Methylation (80 – 85°C temp. for a period of 18 – 24 hrs.) with
37 – 41% formaldehyde soln. / formalin.990 kg of formalin1000 – 1100 lts of water
3rd Step: Alkali fusion [NaOH / Na2CO3] with
NaOH = 0.7 kg [48%] i.e. Caustic lye.NaCO3 = 1.5 to 1.6 kg.And then final product is achieved.
In the preparation of Alkyl naphthalene Sulphonate solution 2:1 mole ratio ofnaphthalene and HCOH is taken and methylation is carried around 80-85ºC,followed by sulphonation in the presence of 98% H2SO4 at around 160-170ºCwhich is followed by alkali fusion.
Impact of leveling agent on physical properties of the substrate
Leveling agents have no effect on physical properties of the substrate as they donot interact with the textile fiber. They have profound effect on the dye moleculeonly.
Method of removing leveling agent
Generally leveling agents are removed simply by boating with 2-3 gpl NaOH and2-5 gpl of sodium hydrosulphate at 80-85ºC for 30 min followed by hot wash andcold wash.
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
0 Comments Bangladesh Textile Today
Share⤤
Start the discussion…
Be the first to comment.
Recommend
Limitation of leveling agent:
Depth of the shade is reduced by 10 to 15%. Therefore, in case of Leveling agentadd 10 to 15% more dye from the recipe.
Bibliography
1. K.A.Thakor, N.C shah and R.M Mittal, Amer, Dyest.Rep., 76(9) 58, 1987.2. A.Murry and K.Mortimer, JSDC, 87, 1971.3. D.Fiebig and H.Herlinger, Text. Prax, Int, 38,785,1983.
Share this news
0Like Tweet 0 Share
pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API
Some of the best innovations in textile start off fromother …1 comment • 10 months ago
amit kumar das — Nice
Fashion merchandising : sourcing1 comment • 10 months ago
Al amin — WeBangladesh. i am
Textile blogging, a new tool in textile learning1 comment • 8 months ago
Noor Ahmed Raaz — textile blogging is the new conceptin our country. I was looking for …
10 important things…1 comment • 8 months ago
Shawon Islam
ALSO ON BANGLADESH TEXTILE TODAY
Subscribe✉ Add Disqus to your sited Privacy
© 2015 Amin & Jahan Corporation Ltd. All rights reserved. Powered by Jewel