Thursday, April 15, 2010
Friday, April 9, 2010
Polyester Microfibers:- Dyeing and Wet Processing
Microfiber
Due to their fineness, the total surface area of microfibre yarn or fabric is far greater than ordinary fibres. Threfore
5.Larger external surface means an increase in number of threads exposed to light which, on destruction of dye, is expressed as lower light fastness rating.
6. Wash fastness and color fastness to rubbing is also poor.
7.Staple microfibres offer difficulty in carding.
The problems in wet processing of microfibers can be overcome by
1.Better knowledge about the size applied and optimum parameters during desizing operation.
To achieve satisfactory dyeing effects ,desizing and refining process must be done before dyeing and after desizing and refining , there should be no impurities left such as electrolyte, antistatic finishing agent , spin finishes and blot.
2.Pre-setting
Suitable pre setting conditions ( time ,temperature and tension) helps not only in stable dimensional stability ,softness but also better dyeing results.
3.Alkali weight reduction
Alkali weight reduction s to treat the fabric with concentrated alkali at high temperature.fber molecule hydrolyse under this condition and lose some weight with change in properties, thus space occurs between crossing points and rubbing resistance relative to slippage among yarns becomes small.Alkali weight reduction makes fabric soft, liveliness, limber and improved absorption.
2.Careful selection of the dyes.
Proper dye selection which are
1.Compatible
2.Having same exhaustion rates
3.Having high wash fastness properties.
4.Good migration and levelling properties
eliminates problems regarding build-up and fastness properties.
Disperse dyes for polyester microfibers
3.Optimizing the dyebath conditions and dyeing cycle.
Optimised dyeing cycles can be worked out by controlling the temperature to account for the high rate of dyeing and to eliminate the risk of uneven dyeing.Chemicals and dyes to be added at, at least 10-20 deg.C lower temperature than normal polyester fiber dyeing. The additions of dyes must be progressive or devided at least into 4 parts. The heating rate must be slow from 40 deg C to 100 deg C. 10-20 min more holding time required at 130 deg C as compared to normal PES.
4.Proper selection of Dyeing machinery.
The dyeing machine must have the required automation to fufil the requirements of microfiber dyeing such as microprocessor controlled dosing , proper and accurate heating rate control etc.
5.Proper selection of dyebath additives
such as
Levelling agents :- A strong levelling agent which shall start working at lower temperatures.
Dispersing agents :- Higher quantities of dispersing agents are needed because amount of dyes required are more to produce the desired depth.
Chelating agents:-
Anticreasing agents,Dyebath softners/Lubricants :- Because microfiber textiles are prone to creasing , therefore use off dyebath lubricants is must.
6.Proper aftertreatment of dyed goods.
Soaping :- In order to obtain satisfactory color effect , fabric should be soaped after dyeing .Soaping is the key process to achieve satisfactory dyeing results on polyester especially polyester / nylon microdenier fabric.
Reduction clear :-Good reduction clear process is needed to achieve satisfactory washing , rubbing and light fastness properties.
Washing :-Is required for neutralising and removing alkali after reduction clear treatment.
Softening, anti soil and antistatic treatment :-Because microdenier fiber easily stains and produces static charges, a hydrophilic ,antistatic and antisoil treatment besides softening is highly recommended to ensure fabric softness and comfortability.
http://www.tex.in/education/nextiles/fib/mic/mic.html
http://ygmfranchise.blogspot.com/2007/07/cleaning-tips-microfiber.html
http://www.microfibergreen.com/is-microfiber-green-product.html
http://www.norwexnow.com/microfiber%20science.html
A synthetic fiber that is extremely soft, lightweight, breathable, durable and ultrafine. In fact, microfibers are two times finer than silk and one hundred times finer than a human hair. Microfiber is currently manufactured from acrylic, nylon, polyester and rayon.Ultra-microfibers on the market are even finer – some having thickness of just 1/200th the thickness of human hair!
Microfibres refer to staple fibres, or individual filaments within yarns, which have fineness less than 1 decitex ( 1 grams per 10,000 meters) and For any fiber to be classified as microfibre yarn, the weight per 10,000 metres of yarn (dtex) is divided by the number of filaments (f), the result must be below 1.
All about microfibers
All about microfibers
Properties of Polyester Microfibers
- Lightweight and flexible
Good stability and shape retention
Anti-wrinkle property
Have a wicking ability that permits perspiration
Comfortable to wear as they are more spongy
Doesn't water stain - superior water repellency is available
Woven or knitted into a very high quality fabric construction
Formerly commenced as a polyester microfiber, today you can find nylon, rayon and acrylic microfibers too.
Strong and durable, water repellent and wind resistant -so tightly woven, that the fabric can't be penetrated by wind, rain or cold
Lightweight, resilient or resist wrinkling, have a comfortable array, preserve shape and resist pilling
The positively charged microfibers draw dust; the tiny fibers are capable to enter the microscopic surface voids most materials
Washable, dries quickly and also washable in at the water temperatures up to 200 degrees and their characteristics will remain intact.
Electrostatic effect - Hair, lint and other dust particles are attracted and grabbed by the microfibers without lifting dust.
The density of the material allowable it to grip six to eight times its weight in water hence high absorbing power capacity
The attraction capability of the microfibers is so sound, even absorbs bacteria and germs - hence can be use as germ or bacteria free purpose
The fabric consists of millions of small tiny conduits that carry oil and grease too.
Benefits of microfibers
Comfortable - very soft, texture like silk, lightweight
Due to its fineness and superior fiber surface area making deep, rich and bright colors achievable
Less "sweaty" in warm weather than usual synthetics
Quickly cleanable - clean just with water
Highly intense and shrink-resistant
Presents insulation and breathability
Change without help - to establish lovely drape
Very fine - finer than the most precise silk
More reusable for cleaning alternative - compared to other mops more efficient and long life
Due to their fineness, the total surface area of microfibre yarn or fabric is far greater than ordinary fibres. Threfore
1.Due to its special structure ,micro fibers has much larger quantity of size ,oil agents and wax on warp yarns.
2.Since microfibres have very small interstitces, with consequent difficulties of size accessibility and duffusibility, desizing becomes quite difficult and costly.
3.Microfibres have greater absorption area resulting in a dyeing rate four times higher than that of normal, which can cause unlevelness in dyeing.
4.They also require more dyestuff than standard fibres to obtain the same depth of shade. 5.Larger external surface means an increase in number of threads exposed to light which, on destruction of dye, is expressed as lower light fastness rating.
6. Wash fastness and color fastness to rubbing is also poor.
7.Staple microfibres offer difficulty in carding.
The problems in wet processing of microfibers can be overcome by
1.Better knowledge about the size applied and optimum parameters during desizing operation.
To achieve satisfactory dyeing effects ,desizing and refining process must be done before dyeing and after desizing and refining , there should be no impurities left such as electrolyte, antistatic finishing agent , spin finishes and blot.
2.Pre-setting
Suitable pre setting conditions ( time ,temperature and tension) helps not only in stable dimensional stability ,softness but also better dyeing results.
3.Alkali weight reduction
Alkali weight reduction s to treat the fabric with concentrated alkali at high temperature.fber molecule hydrolyse under this condition and lose some weight with change in properties, thus space occurs between crossing points and rubbing resistance relative to slippage among yarns becomes small.Alkali weight reduction makes fabric soft, liveliness, limber and improved absorption.
2.Careful selection of the dyes.
Proper dye selection which are
1.Compatible
2.Having same exhaustion rates
3.Having high wash fastness properties.
4.Good migration and levelling properties
eliminates problems regarding build-up and fastness properties.
Disperse dyes for polyester microfibers
3.Optimizing the dyebath conditions and dyeing cycle.
Optimised dyeing cycles can be worked out by controlling the temperature to account for the high rate of dyeing and to eliminate the risk of uneven dyeing.Chemicals and dyes to be added at, at least 10-20 deg.C lower temperature than normal polyester fiber dyeing. The additions of dyes must be progressive or devided at least into 4 parts. The heating rate must be slow from 40 deg C to 100 deg C. 10-20 min more holding time required at 130 deg C as compared to normal PES.
4.Proper selection of Dyeing machinery.
The dyeing machine must have the required automation to fufil the requirements of microfiber dyeing such as microprocessor controlled dosing , proper and accurate heating rate control etc.
5.Proper selection of dyebath additives
such as
Levelling agents :- A strong levelling agent which shall start working at lower temperatures.
Dispersing agents :- Higher quantities of dispersing agents are needed because amount of dyes required are more to produce the desired depth.
Chelating agents:-
Anticreasing agents,Dyebath softners/Lubricants :- Because microfiber textiles are prone to creasing , therefore use off dyebath lubricants is must.
Soaping :- In order to obtain satisfactory color effect , fabric should be soaped after dyeing .Soaping is the key process to achieve satisfactory dyeing results on polyester especially polyester / nylon microdenier fabric.
Reduction clear :-Good reduction clear process is needed to achieve satisfactory washing , rubbing and light fastness properties.
Washing :-Is required for neutralising and removing alkali after reduction clear treatment.
Softening, anti soil and antistatic treatment :-Because microdenier fiber easily stains and produces static charges, a hydrophilic ,antistatic and antisoil treatment besides softening is highly recommended to ensure fabric softness and comfortability.
Recommended Dyeing Cycle for polyester Microfibers
Dianix PLUS( Dystar) or Longsheng is a new range of five compatible, level-dyeing dyes for reliable dyeing of medium and heavy shades, especially on microfiber and weight-reduced polyester, whether applied under mild alkaline conditions to control trimer, or under conventional acid conditions.
Dianix E-PLUS" for Pale Shades on Polyester Fabrics
Fashion application of polyester
Dianix E-PLUS" for Pale Shades on Polyester Fabrics
Fashion application of polyester
Application of polyester Microfibres
Microfibers are most commonly found in polyester and nylon. Some rayon and acrylic micros are in production and available to consumers. Micros can be used alone or blended with conventional denier man-made fibers as well as with natural fibers such as cotton, wool, and silk.
In textiles
Microfibers are used in a variety of fabrics, but most commonly in dress and blouse weight garments. Suit jackets and bottom weights are becoming available. Look for micros in lingerie, rainwear, outdoor fleece and wind-resistant sportswear, as well as tents, sleeping bags, track and jogging suits. The strength of microfibers make them particularly adaptable to sueded or sandwashed finishes because of their extensive fiber surface area and the use of strong fibers like polyester and nylon. As a result, many microfibers simulate the appearance of sandwashed silk.
Other Main products for which microfiber are ideally suited:
- Microfiber Glass Cloth
- Duster/Multi-purpose Microfiber Cleaning Cloth
- Microfiber Scrubber
- Microfiber Kitchen Cloth
- Microfiber Optical & CD Cloth
- Microfiber Mops
- Microfiber Cleaning Sponge
- Microfiber Cleaning Cloths – Terry Cloths, Suede Cloths, Waffle-Weave Cloths
http://www.tex.in/education/nextiles/fib/mic/mic.html
http://ygmfranchise.blogspot.com/2007/07/cleaning-tips-microfiber.html
http://www.microfibergreen.com/is-microfiber-green-product.html
http://www.norwexnow.com/microfiber%20science.html
Monday, April 5, 2010
Sublimation Fastness Of Disperse Dyes
Sublimation is the process of phase change from solid to gas , without going into liquid phase.
Fastness to sublimation is probably the most important requirement of dyed polyester, apart from fastness to light. The migration behavior and wet fastness of disperse dyes on polyester are closely involved with their response to heat treatments.
Adequate fastness to heat is essential so that the dyed material will withstand the conditions encountered in
1. Heat setting,
2. Durable pleating
3. Ironing or pressing of the goods during the making-up of garments.
4. Finishing processes where high temperature is involved.
5. Thermal fixation of prints.
The poor sublimation fastness results into following problems
1.Change in original shade
2.Staining on adjacent fibers in contrast dyed fabrics.
3.Poor color yield and fixation rate in thermal fixation of prints.
4.Staining of dyed polyester sewing threads after stitching and embroidery in contrast stitched and embroidered articles.
5.Cross staining during storage.
How to avoid the problem due to poor sublimation fastness
Since the problem of poor sublimation is concerned to polarity of substation groups in dye molecule , therefore following steps are suggested to avoid the problem,
1.Pre heat setting most of the fabrics before dyeing.
2.Carefully selecting the dyes so that all component yarns have satisfactory fastness in multicolored/contrast color designs ,where fabric is post heat set.
3.Selecting high sublimation dyes for dark shades , and medium /low sublimation dyes for pale shades.
4.The sublimation fastness influenced by the dyeing conditions and dyeing cycle followed, therefore the dyeing cycles must be optimized for best sublimation fastness.
How to test the sublimation fastness of disperse dyes
The sublimation fastness of disperse dyes is usually tested for staining and shade change , tested at 180 oC /210 oC for 30 seconds and rating is done on 1-5 grey scales.
Standard Test Method for Sublimation fastness testing.
AATCC Test Method 117-2004
ISO 105-P01.
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