Textile Effects

METHOD TO ACCESS QUALITY OF PROCESS AFTER EVERY STAGE OF PROCESSING

RAJESH VIG & YASH RATTANB.TECH (TC) 6TH SEM.

Textile Effects

INTRODUCTION

TO

PRETREATMENT

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High and even hydrophilicity / rewettability Good desizing effect High degree of whiteness Removal of seed husks Removal of foreign substances from the fibers Lowest possible fiber damage High color yield Levelness of the effect

Aim of the pretreatment

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Fibres (natural or synthetic materials)

Structure / Makeup / End use (Woven goods, knit goods, yarn ….)

Machine (Continuous, Discontinuous, Semi-continuous)

Chemicals (Wetting-/Washing agents, Complexing agents ….)

Pretreatment processes (Desizing, Scouring, Bleaching ….)

Pretreatment is dependent on

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The classical steps of pretreatment: cotton

woven goods

Singeing Burning down of the protruding fibers

Desizing Removal of sizing agents

Scouring/ Improvement in hydrophilicityAlkaline Cracking Cracking of seed husks

Removal of foreign substances

Bleaching Destruction of colored substances

Removal of seed husks

Mercerizing/ Modification of the inner surfaceCaustifying

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Starch is a polysacharide and consist of:

• 14 - 27% amylose (water soluble)• 73 -86% amylopectin (water insoluble)

Natural sizes Natural sizes (water insoluble)(water insoluble) Synthetic sizes Synthetic sizes (water soluble)(water soluble)

Polyvinyl alcohol size (PVA)Polyacrylate size (PAC)Polyester size (PES)

Carboxymethyl cellulose (CMC)

Desizing: Sizes

PROCESS CONC.(g/l) TIME(hr) TEMPERATURE(C)

Rot steeping ---- 10-16 30-40

Acid desizing 5-10 03-04 40

Enzymatic desizing 1-3 6.8- 7.5 50-60

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Desizing efficiency is found in two ways CONVENTIONALand TEGEWA method.

Conventional Method:

In this method we first take the weight of the sized fabric, let it be W1. Then desize the fabric, dry & take the weight, let it be W2. After that the fabric is treated with 3gpl (35%) HCl at 70*C for 30 min. dry & take the weight of the fabric. Let it be W3.

Total size = W1-W3.

Residual size = W2-W3.

Desizing Efficiency = (Total size – Residual size)/Total size X 100.

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Reagent: potassium iodide (10 gm. Of KI (100%) in 100 ml water, add 0.6358 gm of iodine (100%) stir and shake; iodine is completely dissolved. Fill up to 800 ml with water then complete to 1000 ml with ethanol.

Method:

1. Spot drop wise solution onto fabric.

2. Rub in gently.

3. Assess change of color.

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No change of color = no starch size present.

Pale blue to bluish = presence of starch size or blend

Violet =of starch size with synthetic size

Desized fabric:

Pale blue to bluish violet = refer to violet scale TEGEWA This indicates residual Starch content.

TEGEWA-Violet scale

Assessment of the pretreatment effects: Desizing

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Boiling out is the treatment of cellulose under strong alkaline conditions.

Raw cotton contains a great number of foreign substances such as hemicelluloses, proteins, lignins, pectins, fats, waxes, natural dyes and seed husks. These are partly water-soluble, partly only removable by an alkaline process. In some cases an acid treatment is necessary.

Seed husks and cotton waxes can only be eliminated by longer alkaline boiling or kier boiling. This process is important to improve the hydrophilicity (a must for continuous dyeing and printing). A boiling process is also useful to reduce the danger of a catalytic damage in a subsequent peroxide bleach.

Scouring / Alkaline Cracking

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There are several method to check the efficiency of scouring process which are:

Measurement in weight loss Drop penetration test Wicking test MEASUREMENT IN WEIGHT LOSS Take 5g of dried sample and treat it with 200ml of 1% NaOH for 1 hr.at

80*C Rinse the sample and run out it in hot water. Then treat it with 200ml of 0.5%HCL at 80*C for 1 hr. Then Rinse Boil in distilled water(1/2hr.) Dry Weigh NOTE:Weight lose in scouring is normally 6-9%

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Scouring process increase the absorbency of fabric due removal of oil and waxes.

Absorbacy of fabric can be estimated by “Drop Penetration test” In this method drop of distilled water is allowed to remain in contact

with the scoured cloth for30sec. If the drop absorbed in this time, the material is jugged to be

absorbent .Hence it showed that efficient scouring done In case of printing the time of absorption of drop of water must be

lower then 1sec.

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Wicking or capillary action may be observed by timing the rate at which water climbs up a narrow strip of fabric suspended vertically with its lower end dipping into the water.

METHOD: A square of fabric,2”X 2”is fully immersed in water at20*C . Then access the efficiency of process by TEGEWA- Wicking-scale.

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Several methods: TEGEWA- Wicking-test

“modified wicking-test”

“modified wicking-test” (measurement of the capillary

rise)

time goodness of the hydrophilicity(sec/cm)

0 - 3 extremely high3 - 5 very good5 - 8 good, acceptable >8 process to be examined

“modified wicking-test” (measurement of the capillary

rise)

time goodness of the hydrophilicity(sec/cm)

0 - 3 extremely high3 - 5 very good5 - 8 good, acceptable >8 process to be examinedReference for 100% cotton

Assessment of the pretreatment effects: Hydrophilicity

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Bleaching means, to destroy the natural dyestuff in the fibre.

There are two chemically different bleaching processes:

Oxidative bleaching with hydrogen peroxide, sodium hypochlorite, sodium chlorite or peracetic acid Reductive bleaching with stabilized hydrosulphite preparations and sulphoxylates.

The choice of chemicals depends on the required degree of whiteness, on technological and ecological aspects, on the machinery and on economic aspects.

Overdosing of the bleaching chemicals, insufficient temperature regulation, too long bleaching times, existence of catalysts, insufficient stabilizing, etc. may lead to damaging of fibers.

Bleaching

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Absolute value for assessing bleached goods is difficult to define, since they are invariably associated with the subsequent use of the fiber, yarn or fabric.

The factors which form the basis of assessment include: 1.     Whiteness 2.     Chemical or physical damage 3.     Absorbency, particularly of cellulose materials and blends. 4.     Presence of residual non-cellulose matter. 5.     Levelness of preparation. 6.     Freedom from impurities, e.g., cotton seed 7.     Suitability for subsequent processes e.g., spinning, dyeing etc.

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Whiteness is a relative term , measured with the help of an instrument known as – SPECTROPHOTOMETER

The instrument helps to measure the reflectance data of the substrate ( without color) and using this data in formulas coverts it into various whiteness readings such as :

GanzCIEStensbyBergerISO/Tappi .. etc

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W=Y+800(Xn-X)+1700(yn-y) Where x,y are the calorimetric values and xn,yn are

chromaticity co-ordinates of light source. YI= 128X-106Z Y Where X,Y,Z are tristimulus value.

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The leftover peroxide can cause serious problems in further reactive dyeing

The depth of certain dyes can be lost up to 40%

Turquoise, blues and reds are especially sensitive to peroxide

For peroxide killing either a reductive base product or a catalase enzyme based product can be used.

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Influence of peroxide on reactive dyeing

With Invatex PC Without Invatex PC

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Caustic concentration 270 - 330 g/l NaOH 100% (28-32 °Bé)Caustic temperature 15 - 20 °C (hot mercerization 60 - 90 °C)Reaction time 45 - 60 sec. (hot: shorter time)

Tension against shrinkageStabilizing up to about 50 g/l NaOH 100%Mercerizing wetting agent for quick and even wettingPretreatment raw, desized, boiled off, bleached

MercerizingIn this process cotton fabric is treated with caustic sol. This treatment

cause fibre to swell and give lustrous appearance

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Mercerizing Effects

•Increase in colour depth.• Covering immature and dead cotton.•Dimensional Stability.•Increase in tensile strength.

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There are several method to check the efficiency of Mercerization process which are:

Visual assessment Determination of Swelling index Barium activity number(BAN)

Visual assessment: This is the simplest method used in textile industry. This assessment based on a comparison of the test sample

with standard sample. A viewing angle of 45* is generally recommended and position

of samples are changed several times during the test.

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In this method the yarn together with weight(0.8g) is hanged into measuring cylinder containing sufficient amount of solvent as to dip upper end of the yarn .

The yarn is then allowed to untwist. Number of revolutions made by weight are measured for 3 min. Swelling index=untwisting no. in solvent untwisting no. in waterNOTE:Swelling index increases with degree of mercerization

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Marcerized sample absorbs barium hydroxide to the greater degree than NaOH and from practical point of view barium hydroxide is more easy to estimate.the ratio of uptake of reagent has been referred to barium activity number.

Method: In this procass 2g of mercerized and unmercerized sample are placed

separately in two conicle flask containing 30ml of N/4 barium hydroxide and left for 2hr.

10ml of clear solution is withdrawn and titrated it against N/10 HCL using phenolphthalein as indicator.

A blank titration is also carried out on the measured barium hydroxide sol. Using methyle red as indicator.

BAN=b-s X100 b-u

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Where, b= ml required for blank test s= ml required for mercerized cotton u= ml required for unmercerized cottonNOTE:BAN of unmercerized cotton 100BAN of semi mercerized cotton 115-130 BAN of mercerized cotton ~ 155

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IINDRODUCTION

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DYEING

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It is the process of imparting colours to a textile material in loose fibre, yarn, cloth or garment form by treatment with a dye.

For most of the thousands of years in which dyeing has been used by humans to decorate clothing or fabrics for other uses.

the primary source of dye has been nature, with the dyes being extracted from animals or plants

In the last 150 years, humans have produced artificial dyes to achieve a broader range of colors, and to render the dyes more stable to resist washing and general use.

Different classes of dye are used for different types of fiber and at different stages of the textile production process from loose fibers through yarn and cloth to completed garments.

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There are several method to check the efficiency of dyeing process.which are given below:

FASTNESS TO CROCKING. FASTNESS TO WASHING. FASTNESS OF PERSPIRATION. FASTNESS TO WATER. FASTNESS TO LIGHT.

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Method: Condition the sample at temperature of 20+ 2*C and relative humidity

of 65+ 2% for 4 hr. Cut the sample of size 5x13cm . Place the sample on the base of crock meter and place holder over it. Mount the bleached cotton cloth on the finger with help of clip. Lower the finger and run 10 complete turns at 1t/sec. Remove the white sample and evaluate it with help of grey scale after conditioning. For wet rubbing wet the white square piece in water and squeeze. Then process in similar manner. and evaluate crocking

fastness with the help of grey scale.

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Method: Add 0.22gm of detergent to 150ml of water. Add this sol. To the container of lounderometer and add 50 stainless

steel balls in it. Prepare the fabric sample of size 8x5cm by stitching

bleached cotton fabric on both side of the sample. Place the fabric sample inside the container and start

the washing cycle for 44min at temperature of 45*C. Then take out the sample, dry it , and evaluate for

wash fastness with the help of grey scale.

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Method: Prepare the standard AATCC sol. Using following recipe: AATCC acidic for 1L sol.

NaCl = 10+ 0.01g

lactic acid= 1+ 0.01gm

sodium hyrogen phosphate =1 + 0.1gm.

Histidine monohydrous chloride =0.25 + 0.1gm.

adjust to pH 4.3 + 0.2 Cut the sample of size 6x6cm and condition it at temp. of 20+2*C and

RH of 65 +2 for 4 hr. Stitch piece of bleached cotton fabric on face side of the sample. Dip the sample in this std. sol of 20min. Take out the sample and squeeze b/w plastic plate. Keep inside the prespiration tester for 6hr. At 37-38*C.

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Take out and dry the sample. Then evaluate for fastness with help of grey scale.

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Method: Condition the sample at temperature of 20+2*C and RH of 65 +2 for 4

hr. Cut the sample of size 4x10cm. Stitch a piece of bleached cotton on face side of dyed fabric. Dip the sample in water for 15 min. Take out the sample and squeeze b/w plastic plates. Keep inside the perspiration tester for 6hr. At 37-38*C. Take out and dry the sample. Then evaluate for fastness with help of grey scale.

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Purpose and Scope   This test method provides the general principles and procedures

which are currently in use for determining the colorfastness to light of textile materials.   The test options described are applicable to textile materials of all kinds and for colorants, finishes and treatments applied to textile materials. 

Test Options included are:1-Enclosed Carbon-Arc Lamp, Continuous Light2-Enclosed Carbon-Arc Lamp, Alternate Light and Dark3-Xenon-Arc Lamp, Continuous Light, Black Panel Option4-Xenon-Arc Lamp, Alternate Light and Dark5-Xenon-Arc Lamp, Continuous Light, Black Standard Option

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  Samples of the textile material to be tested and the agreed upon

comparison standard(s) are exposed simultaneously to a light source under specified conditions.

The colorfastness to light of the specimen is evaluated by comparison of the color change of the exposed portion to the masked control portion of the test specimen or unexposed original material, using the AATCC Gray Scale for Color Change or by instrumental color measurement. 

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INTRODUCTION

TO

FINISHING

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Textile finishing is a term commonly applied to different processes that the textile materials undergo after pretreatments, dyeing or printing for final embellishments to enhance their attractiveness and sale appeals well as for comfort and usefulness.

Finishing treatments are basically meant to give the textile material certain desirable properties like

Softness Lusture Pleasant handle Drape Dimensional stability Crease recovery Antistatic Non-slip Soil release

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There are several types of finishes used on textile fabrics.

Main finishes are: Easy care finishes Flame retardant finishes. Water repellent finishes. Softening finishes. Hand building finishes.

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cotton garments ensure maximum comfort thanks to their suppleness and their capacity to absorb humidity.

The weak point of cotton clothing is its tendency to crease easily, which makes care of such garments more difficult,

The tendency to crease is due to the to partially amorphous structure of the cellulose, which means that structural alterations can quite easily occur.

Many weak molecular bonds such as hydrogen or Van DerWaals forces, which link together long cellulose polymer chains, can alter

In order to limit creasing, Resin can be used which creates stronger (covalent) and more permanent bonds and reduce creasing to a large extent.

Types of cross linking agent used: Formaldehyde based product.(DMU,DMDHEU) Non –formaldehyde based product(DMeDHEU,BTCA)

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Fabric :100 % cottonRECIPE: Siltex 30200/Resin = 120 - 180 g/l Siltex ME 30 = 30 g/l Siltex 30098cs/Asisoft CS = 20 g/l Siltex PE 20 = 10 g/l MgCl2 = 30 - 45 g/lPARAMETERS: Type Of Water Used =Tap Water pH Of Bath = 4 - 5( used Acetic Acid to adjust the pH ) Pick Up = 80 % by weight Temperature = Ambient ( 27 – 28 °C )PROCESS: PAD,DRY & CURE THE FABRIC AT 160 °C FOR 4 MINUTES.

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Method: A specimen is cut from the fabric with template 2”x1”. It is creased by folding in half, placing it b/w two glass platesand adding 2Kg weight. After 1min. the weight is removed and specimen transferredto the fabric clamp on the instrument Allow it to recover from crease. As it recovers the dial of the instrument is rotated to keep the free edge of specimen in the line with knife edge. At the end of time period allowed for recovery ,usually 1min.,the

recovery angle in degree is read on the dial scale. This test is carried out on the both sides of the

fabric.

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Flame retardent finishes mainly used for fire fighter and an emergency personnel require protection from flames.

It is also used for floor covering ,upholstery, when used in building. The military and the airline industry has big use of flame retardant

finishes.

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There are two type of finishes: Durable finishes (THPC) Non durable finishes.(diammonium phosphate).RECIPE: Melamine Resin = 35g/l Pyrovatex CP= 280g/l softner= 25 g/l Acid catalyst= 20g/l Wetting agent= 1.25 g/lPROCESS: PAD,DRY & CURE THE FABRIC AT 150°C FOR 4-5 MINUTES.

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Method: Condition the sample at 105*c in an oven for 30 min. Cooling for 30 min. in a desiccator After this cut the sample of size 3.5”X10” Specimen is mounted in special U shape holder and suspended this

frame vertically in test chamber The sample is subjected to flame along the centre bottom edge for

3sec and allow to burn. The char length of specimen is measured and recorded. NOTE: The fabric said to be flame retardant if ignition time is high and have

tendency to self extinguish.

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Water repellency is the relative degree of resistanceOf a fabric to surface wetting, water penetration, and water absorption. The widely used method of producing water proof fabric

is by coating the fabric with a solid polymeric coating, e.g. neoprene,PVC.

Such solid no porous continue coating are impermeableBoth to passage of air and water vapour.There are four type of finishes used: Paraffin repellent. Stiaric acid-malmine repellent. Silicone water repellent. Flouro-carbon based repellent.

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This test method is applicable to any textile fabric.  It measures the resistance of fabrics to wetting by water.  It is especially suitable for measuring the water-repellent efficacy of finishes applied to fabrics.

  Principle Water sprayed against the surface of a test specimen under controlled

conditions produces a wetted pattern whose size depends on the relative repellency of the fabric. 

Evaluation is accomplished by comparing the wetted pattern with pictures on a standard chart

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These types of finishes are used to add firmness and fullness or to improve hand of the fabric.

It is desirable in certain polyamides and polyester materials for petticoats, collar interlinings, etc.

Hand building can be divided into two groups: Fullness. Stiffness.There are two types of finishes used: Non durable Hand building finishes.(PVA) durable Hand building finishes(Poly vinyl acetate)

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Shirley stiffness tester: cut out the sample according to template. Both sample and the scale are transferred to the platform with the fabric underneath. Both are slowly pushed forward. The movement of template and fabric is continued until the tip of the sample viewed in the mirror cuts both both index lines. The bending length immediately be read off from scale mark. C=L X F (o)Where F(o)={Cos1/2(o)}1/2 { 8tan(o)}

Result :more the length more the stiffness of the fabric.

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The use of soft finishes is now universal. The cost of such a simple treatment is low yetthe result is a dramatic improvement in quality. Chemical after treatment with softener gives agreeableSoft hand, smoothness, drape and pliability.There are four type of finishes used: Cationic softener. Anionic softener . Amphoteric softener. Non ionic softener.

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There are two methods which we used to measure the efficiency of softening process:

Sledge method. Bending length tester.Sledge method: In this method sledge wt. taken is 100g and we require force measuring unit reading upto100g. Then coefficient of friction is measured by given Formula: Coeff. of friction= force to pull sledge(F) wt.of sledge The ratio of dynamic /static friction gives good indicator of type of hand.Note: more the ratio greasy the handle. Lesser the ratio scroopy the handle.

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AATCC test method manual. Google search. Schindller. Heywood.

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Have a Nice Day!THANK YOU

FROM: RAJESH VIG YASH RATTAN