Finishing Zubair, Sohaib, Taimur & Waleed

8/8/2019 Finishing Zubair, Sohaib, Taimur & Waleed

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TEXTILE FINISHING

WATER REPELLENT & WATER

PROOFING OF TEXTILE SUBSTRATE

PRESENTED TO

Dr HANEEF

MEMON

15-07-2010


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GROUP MEMBERS :

1 :M. ZUBAIR ANWER

2 :M.SOHAIB HASSAN

3 :TAIMOOR MAJEED

4 :S.M WALEED

INDUS INSTITUTE OF HIGHER

EDUCATION


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Stain Repellency :

Stain repellency is the ability of a treated fabric to withstandpenetration of liquid soils under static conditions involving only

the weight of the drop and capillary Forces.

Oil Repellency :

Oil repellency is tested by placing a drop of oil on the fabric and

observing whether the drop resides on top the fabric orwhether it penetrates.

The lower the surface tension of the liquid, the better thefabric's resistance to oily stains.

Water Repellency :

Water Repellent fabrics are those which resist being wetted bywater, water drops will roll off the fabric.


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Water Repellent Fabrics :

Water repellent fabrics have open pores and arepermeable to air and water vapor. Water-repellentfabrics will permit the passage of liquid water onceHydro-static pressure is high enough.

Water-Proof Fabrics :

Water proof Fabrics are resistant to the penetration of

water under much higher hydrostatic pressure than arewater-repellent fabrics. These fabrics have fewer openpores and are less permeable to the passage of air andwater vapor


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Physical Chemistry Of Wetting :

Where:

L/V = the interfacial energy between liquid/vapor

S/L = the interfacial energy between solid/liquid

S/V = the interfacial energy between solid/vapor

= equilibrium contact angle


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Surface free energy

when the surface tension of the liquid is lower than the

surface free energy of the solid, the liquid willspontaneously wet the solid.

The surface free energies of typical textile solids are as

follows:

Solid Surface Free energy mN/m

Polyamide (Nylon 6.6 ) 46

Cotton 44

Polyester 43PVC 39

Polyethylene 31

Polysiloxane, typical silicone oil 23-24

PTFE 18


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Repellent Finishes

For fabrics to be water repellent, the Surface free energyof the fibers surface must be lowered to about 24 to 30mN/m. Pure water has a surface tension of 72 mN/m sothese values are sufficient for water repellency.

Paraffin Waxes

The oldest and most economical way to make a fabric water

repellent is to coat it with paraffin wax.

Solvent solutions, molten coatings and wax emulsionsare ways of applying wax to fabrics.

Wax emulsions are the most convenient products for

finishing fabrics.


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The major disadvantage of wax water repellents is poor

durability. Wax is easily abraded by mechanical action and

wax dissolves in dry cleaning fluids. It is also removed by

laundry processes

Wax Emulsion Composition

A typical wax emulsion consists

Paraffin wax as the hydrophobe

Emulsifying agent An emulsion stabilizer

Aluminum

Zirconium salt to deactivate the emulsifying agent when the fabric is

heated.


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Silicone Water Repellents

Resinous polysiloxanes, on the other hand are more resistant to

abrasion and less soluble in dry-cleaning fluids or laundry products

. Three-dimensional crosslinked polysiloxanes fill the need provided

they could be applied to fabrics.

Resinous polymer, making the fabric highly water repellent

Advantages and Disadvantages ofsilicone water repellents

Advantages

Silicone water repellents are durable to washing and dry-cleaning. Silicones are more durable than wax repellents

Less expensive than fluorochemical repellents.

Silicone finishes resist water borne stains

Fabric hand can be made soft and pliable.


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Disadvantages

Durability is brought about by the formation of a sheath of finish

around the fiber. If the sheath cracks, durability is lost.

Adsorption of hydrophilic substances found in dry cleaning andlaundry

Products also impair water repellency.

Less durable than fluorochemical finishes.

Silicones are more expensive than wax repellents

Silicones do not resist oil borne stains.


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FLUOROCHEMICAL REPELLENTS Fluorochemical repellents are unique in that they confer both oil and water

repellency to fabrics.

The ability of fluorochemicals to repel oils is related to their low surface energy

which depends on the structure of the fluorocarbon segment


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Commercial Products

Commercial fluorochemical repellents are fluorine-containing vinyl or

acrylic polymers.

The acrylate monomer will polymerize to form a high molecular

weight polymer that can be converted to an emulsion.

The emulsion dries to a continuous film.

Add-on The amount of fluorochemical needed to achieve oil repellencyis relatively low.Shows that on many fabrics.

An add-on of 0.5% is sufficient to give optimum results.


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REPELLENT FINISHING WITH FLUOROCHEMICALS

The oil and water repellent features of fluorochemical polymers lead

to finishes applicable in two consumer product areas, durablerainwear fabrics and stain/soil resistant products. For rainwear

products,

For fabrics that can be laundered or dry cleaned, stain removal is

more important than stain prevention.

Rainwear The finish is applied by padding the formulation onto fabric, drying

at 120C and curing 1-3 minutes at 150-182oC.

The fabric will give a 100 spray rating initially and an 80 rating after 5home laundering-tumble drying cycles, An 80 spray rating is expected after one dry cleaning cycle. In

addition, oil repellency rating of 5 initially and 4 after laundering or drycleaning is expected.


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Repellent Finishes

Advantages Disadvantages

Peraffin waxes Goodwater repellency,Resistant to water pressure

Low price

Little breathability

No oil repellencyNo wash fastness

Silicones Good water repellencyWater vapor permeabilitySoft handle

Good price/performance ratio

No oil repellencyNo soil repellency

Fluorocarbons Good oil & water repellencyResistance to washing & dry

cleaningSoil repellencyGood price/performance ratio

High price Value


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Nano Technology:

Nanotechnology is defined as The precise

manipulation of individual atoms and molecules to

create layer.

Nano finishing means any technology done on ananometer or (109) meter scale.

The main aim of the nano finishing is the precise

manipulation of an individual atoms and molecules to

create a structure.


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Water Repellence Easy Care-Hydrophobic Nano Finish.

Hydrophobic surfaces can be produced mainly in two ways (i) bycreating a rough structure on a hydrophobic surface (ii)by modifying a

rough surface using material with low surface free energy.

Self Cleaning EffectThis effect is known as lotus effect (fig.4).The lotus effect depends ontwo factors namely super hydrophobicity and very high water contactangle and a very low roll off angle.


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UV-protection

A thin layer of titanium dioxide is formed on the surface of the treated cotton

fabric which provides excellent UV-protection

Nano-Care

Features

Superior Stain, Water and Oil Repellency Resists Wrinkles

Breathable Fabric

Preserves Original Hand

Easy Care


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Nano-Pel

Features Superior Water and Oil Repellency

Minimize Stains

Breathable Fabric

Preserves Original Hand

Easy Care

Durable Performance


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Testing for Water Repellent Finishes:

Water Proof:A water proof fabric is one that coated or impregnated to form a

continuous barrier to the passage of water example rubber, polyurethane, PVC

or wax coating.

Shower Proof:Fabric is often achieved by coating with a thin film of a hydrophobic

compound such as silicon.

Bundesmann Water Repellency Tester:


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Technical Specifications:

Diameter oftestspecimen: 140 mm

Diameter oftest opening 100mm

Rate ofcollection of waterineach

cup

65+ 3ml/minute

Distance betweennozzletipand

specimencentre

150 cm

Speed ofrotation ofcupassembly 5rpm

Distance betweencenter of

specimenand verticalAxis ofrotation ofcupassembly

105+10 mm

Thickness of wiper blades 5.08 to5.13mm

Radius ofcontactedges of wipers 6.35mm

Loadexerted onspecimen by

wipers

400 +50mg


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SPARY RATING

Grade Description:Complete wetting of the whole of the sprayed surface.Wetting of more than half of the sprayed surface.

Wetting of the sprayed surface only at a small discrete areas.No wetting of but appearance of small drops to the spayed surface.

No wetting of and no appearance of small drops to the sprayed surface.


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Finishing Zubair, Sohaib, Taimur & Waleed