Showing posts with label Shade matching. Show all posts
Showing posts with label Shade matching. Show all posts

Friday, April 9, 2010

Polyester Microfibers:- Dyeing and Wet Processing

Microfiber
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
Properties of Polyester Microfibers




  1. Lightweight and flexible

  2. Good stability and shape retention

  3. Anti-wrinkle property

  4. Have a wicking ability that permits perspiration

  5. Comfortable to wear as they are more spongy

  6. Doesn't water stain - superior water repellency is available

  7. Woven or knitted into a very high quality fabric construction

  8. Formerly commenced as a polyester microfiber, today you can find nylon, rayon and acrylic microfibers too.

  9. Strong and durable, water repellent and wind resistant -so tightly woven, that the fabric can't be penetrated by wind, rain or cold

  10. Lightweight, resilient or resist wrinkling, have a comfortable array, preserve shape and resist pilling

  11. The positively charged microfibers draw dust; the tiny fibers are capable to enter the microscopic surface voids most materials

  12. Washable, dries quickly and also washable in at the water temperatures up to 200 degrees and their characteristics will remain intact.

  13. Electrostatic effect - Hair, lint and other dust particles are attracted and grabbed by the microfibers without lifting dust.

  14. The density of the material allowable it to grip six to eight times its weight in water hence high absorbing power capacity

  15. The attraction capability of the microfibers is so sound, even absorbs bacteria and germs - hence can be use as germ or bacteria free purpose

  16. The fabric consists of millions of small tiny conduits that carry oil and grease too.

  17. Benefits of microfibers

  18. Comfortable - very soft, texture like silk, lightweight

  19. Due to its fineness and superior fiber surface area making deep, rich and bright colors achievable

  20. Less "sweaty" in warm weather than usual synthetics

  21. Quickly cleanable - clean just with water

  22. Highly intense and shrink-resistant

  23. Presents insulation and breathability

  24. Change without help - to establish lovely drape

  25. Very fine - finer than the most precise silk

  26. More reusable for cleaning alternative - compared to other mops more efficient and long life
Dyeing of polyester Microfibers
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.
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.


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

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
Microfiber Makes the Grade
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







 

Friday, February 12, 2010

Color Matching in Textiles

Colour is one of the most fundamental aspects of textile design which contributes greatly to the overall visual effect of a finished fabric. Colour matching is a vital process in ensuring continuity of colour from the master standard to all subsequent production batches.
A variety of conditions affect how a color looks
1.Light- source difference
2.Observer Difference
3.Size Difference
4.Background Difference
5.Directional difference
How to Ensure Effective Color in Today's Manufacturing Processes?
The three components of colour matching
There are three components involved in colour viewing,which are  LIGHT, VISION and OBJECT. If any omponent changes, the actual perception of colour will also change.
It is important to keep the conditions (as mentioned above) constant when viewing colors.
Colour matching requires the use of a standard light box which has several illuminants:-

 Some of the standard light sources 

  • A - tungstun

  • CWF - Cool White Fluorescent

  • TL84,  

  • UV,

  • U30
Learn about Various Light Sources
Importance of color Management
Everybody's perception of colour is slightly different. Light boxes are therefore employed so that whenever samples are viewed the conditions are exactly the same.
Color Viewing booth / light box for color matching.


It's difficult to see the true color under different light sources in which measurement color deviation intends to occur when performing the color evaluation without a standard light sources. To simulate different light sources to obtain an objective color, color difference and color evaluation, we can put the test specimen into the color viewing booth / color light box, so that it's easily to see the true color daytime, night, indoor and outdoor, and ensure the color consistency.
The Problem of Metamerism
Metamerism in textile shade matching is defined as a phenomenon in which two colored objects appear same in one light source but differ when the light source is changed. This could be due to difference in pigments or materials.
The spectral reflectance characteristics of the colors of two objects are different , but the resulting tristimulus values are same in under one light source but different in another.
Color Measurement Methods for Textile Fabrics
Color Tolerances for Consistent Pass/Fail Decisions
Every colour has a colour space which can be pinpointed by coordinates given by a computer. Colour can also be checked by eye and given a colour space, but again this is open to subjectivity.
The three fundamental aspects of colour are lightness, chroma and hue.
Lightness( bright colors,dark colors,light colors, the lightness of color changes vertically) is shown on the "L" axis. It indicates the depth of a colour, ranging from white to black with grey in between. One way of picturing depth of colour would be to imagine a black and white photograph where every colour is shown as a different depth of black, white or grey. The lightness of the fabric sample would be represented by a number on the "L" axis.
Chroma or saturation ( Vivid colors, dull colors, chroma changes outward from the center) is shown as the distance away from the "L" axis.
If the colour is described as being at the very outside edge of chroma it will appear to the observer to be very clean and bright. As it moves towards the grey central "L" axis it will become greyer, flatter and more dirty.
Hue (Redder, greener, yellower, bluer etc. hues form the color wheel) is the variation in colour. For example, a blue may be very red - moving towards purple lilac - and would appear in the blue colour space at the red side. Different shades of blue would all appear in the blue colour space but in different areas.
Lightness, chroma and hue are checked on all yarns and piece dyed fabrics to ensure colour continuity standards are maintained to the highest levels. They can be represented as a three dimensional figure.


More Information on Color Theory


A Note on Color Inconstancy
Read Book on Color Space conversions
CIE color model

Complementary colors
Electromagnetic energy
Desaturation
Gamut
Grayscale
HSV color model
Hue
Light primary colors
Print primary colors
Saturation
Secondary colors

Background knowledge of different light sources
CIE Fluorescent Illuminants
Artificial Daylight D65 which corresponds to a mid-day sun in Western Europe / Northern Europe is a commonly-used standard illuminant defined by the CIE. It is part of the D series of illuminants that try to portray standard illumination conditions at open-air in different parts of the world. Artificial Daylight D65 light sources do not exist actually, only simulators. The quality of a simulator can be assessed with the CIE Metamerism Index. —CIE S005/E-1998.

TL84 - CIE Fluorescent Illuminants, Light Source (F11), TL84 light sources represent a tri-band fluorescent lamp. —CIE 1931.

CWF - CIE Fluorescent Illuminants, Light Source (F2), CIE F series light sources represent various types of fluorescent lighting. CWF(Cool White Fluorescent) light sources found in office environments.

Incandescent A - CIE Incandescent A is intended to represent typical, domestic, tungsten-filament lighting. Its relative spectral power distribution is that of a Planckian radiator at a temperature of approximately 2856 K. CIE standard Incandescent A should be used in all applications of colorimetry involving the use of incandescent lighting, unless there are specific reasons for using a different illuminant. It is found in our home.

UV - UV Ultra Violet Black light to reveal the presence of fluorescent dyes and bleaches.

U30/U35 - Neutral-white fluorescents have a CCT (Correlated color temperature) of 3000K or 3500K.

Friday, November 20, 2009

Light Sources

What are the systems of defining the light sources?
CIE Rating - Based on CIE Publication 51, it is a very strict rating of a light source’s ability to reproduce daylight, in both the visible and ultraviolet spectrums. The first letter provides the rating for
the visible spectrum and the second letter the rating for the UV spectrum. An “AA” rating is the highest and “EE” the lowest. A rating of “BC” or better is acceptable for color matching applications.

To Learn about various light sources Click Here
Color Rendering Index (CRI) - A rating of a light sources ability to reproduce a daylight source. The Color Rendering Index is a scale (0-100) that represents how closely a light source depicts or reflects an object's true color. As a general rule of

thumb, the higher the CRI, the more accurate an object will appear. In the lighting industry, , a rating of 92 or higher is required for critical color evaluation applications.and depicts a truer color.

Color Temperature (AKA Correlated Color Temperature) - A rating of a light sources color output. It is based on the Kelvin scale in which 0 degrees is at Absolute Zero (-273 C) where all motion in a molecule is deemed to stop. The lower the color temperature of the light source, the redder the source will be. Inversely, the higher the color temperature of the source, the bluer it will be. Some common color temperatures, common names associated with them and their associated colors are:
7500K (D75) North Sky Daylight Moderate to Deep Blue
6500K(D65) Average Daylight Moderate Blue
5000K (D50) Equal Energy Daylight White
4100K Various fluorescent sources Greenish
3000K Various fluorescent sources Orangish
200K Tungsten A Red/Yellow
2865K Illuminant A Yellowish Red
2300K Horizon Reddish

What are the standard light sources for textile shade matching?
D75 (Color temperature 75000K) - “North Sky Daylight.”
A bluish colored light source originally used for grading cotton and other evaluation applications.
D65/ F7 (Color temperature 65000K) – “Day Light”
A light bluish colored light source used in color matching applications of paints, plastics, textiles, raw inks, and other manufactured products. It is the only daylight source that was actually measured.
D50 (Color temperature 50000K)
A near white light source used in the evaluation of graphic arts and imaging applications.
Ultra Violet(UV Light)
UV Light energy not normally visible to the human eye, but which is present in natural daylight. UV energy has the ability to excite certain substances (such as optical brightening agents) within a sample causing them to emit light in the visible spectrum, usually in the blue region.
F2( also called F,F02,Fcw,CWF,CWF2)Cool White Fluorescent (CWF Color temperature approx 41000K)
A wide band single phosphor fluorescent source commonly used in commercial lighting applications and office environment..
F11 :- represents a narrow tri band fluorescent at 40000K color temperature.
Warm White Fluorescent & TL830(WWF Color temperature approx 30000K)
A wide band single phosphor fluorescent source used in commercial lighting applications.
TL84(Color temperature approx 41000K)
A narrow band tri-phosphor fluorescent source originally designed for commercial lighting applications.
TL835(color temperature of approximately 35000K )
A narrow band tri-phosphor fluorescent source originally designed for commercial lighting applications.
Ultralume 30 (U30 or 30U Color temperature approx 30000K) - A narrow band tri-phosphor fluorescent source originally designed for commercial lighting applications
Ultralume 35 (U35 or 35U color temperature of approximately 35000K) - A narrow band tri-phosphor fluorescent source originally designed for commercial lighting applications
Source A :-Incandescent and Tungsten Illumination
A typical light bulb found in the home is an incandescent tungsten lamp. It uses a tungsten filament that will glow when electricity is passed through it. These lamps are very common and are used in color match applications where a yellowish to red source is required.
Source C :- it is a historical representation of average sky day light at 67740K .
Tungsten A (3200K )–
is used primarily in the photographic, film and video industries where a “whiteish” source and continuous light output are required. It is not commonly used for color matching applications.
Illuminant A(2865K) - is a standardized illuminant described in the international standard, CIE Publication 15.2 and specified for use in color matching applications in ASTM D1729-96. It is used where a yellowishred source is required. It is the predominant source/illuminant used for both instrumental and visual color matching applications.
Horizon(2300K )-
Reddish Source described in older specifications and used for color matching applications Horizon in an outdated standard as an “Incandescent illumination of low correlated color temperature it is not used in instrumental color matching applications.

Name of    CCT (0K)              CRI                    description
light
source
A                 2856                       98         Incandescent tungsten
B                 4874                                     Obsolete, direct sunlight at
                                                                  noon
C                 6774                                     Obsolete, north sky daylight
D50            5003                       98        ICC Profile PCS. Horizon light.
D55            5503                                     Compromise between
                                                                  incandescent and daylight
D65           6504                        98        Television, sRGB color
                                                                 space
D75           7504                         96        North sky day light
E               5454                                       Equal energy
F1             6430                                      Daylight Fluorescent
F2             4230                        62        Cool White Fluorescent
F3             3450                         54       White Fluorescent
F4             2940                        51         Warm White Fluorescent
F5            6350                                      Daylight Fluorescent
F6            4150                                       Lite White Fluorescent
F7            6500                        98         D65 simulator, day light
                                                                simulator
F8            5000                        98         D50 simulator, Sylvania
                                                                F40 Design
F9            4150                                     Cool White Deluxe
                                                                Fluorescent
F10          5000                                     Philips TL85,
                                                                Ultralume 50
F11          4000                        83         Philips TL84,
                                                                Ultralume 40
F12           3000                        85        Philips TL83,
                                                                 Ultralume 30
Further readings
Light Bulb Colour Temperatures
Explanation of various light sources

FAQs about “Daylight” Lighting