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FUNCTIONAL FINISHES

PRESENTED BY:DIBYATA NANDANABANEETA DASSANDEEP MOHANTYSNEHASISH DEYSUMAN NAYAK

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Functional Finishes

• These finishes improve the performance properties of fabrics Improved / Altered Performance

TYPES OF FUNCTIONAL FINISHES1. Antimicrobial2. Antistatic3. Crease resistant4. Durable press5. Flame resistant6. Soil release7. Water and stain repellent8. Waterproof

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Antimicrobial Finishes

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 This finish causes a fabric to inhibit the growth of microbes.

The humid and warm environment found in textile fibers encourages the growth of the microbes.

Infestation by microbes can cause cross-infection by pathogens and the development of odor where the fabric is worn next to skin.

In addition, stains and loss of fiber quality of textile substrates can also take place. 

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Objectives: To avoid cross infection by pathogenic micro

organisms; To control the infestation by microbes; To arrest metabolism in microbes in order to

reduce the formation odour; and To safeguard the textile products from staining,

discolouration and quality deterioration. To control microorganisms

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The following requirements need to be satisfied to obtain maximum benefits out of the finish:

Durability to washing, dry cleaning and hot pressing Selective activity to undesirable microorganisms Should not produce harmful effects to the manufacturer, user

and the environment; Compatibility with the chemical processes Easy method of application No deterioration of fabric quality Resistant to body fluids and Resistant to disinfections/sterilization.

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Antimicrobial Finishing Methodologies:

The antimicrobial agents can be applied to the textile substrates by exhaust, pad-dry-cure, coating, spray and foam techniques.

The substances can also be applied by directly adding into the fibre spinning dope.

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BENEFITS :

Uniforms, tents, defense textiles and technical textiles, such as, geotextiles Home textiles, such as, curtains coverings, and bath mats The application of the finish is now extended to textiles used for outdoor,

healthcare sector, sports and leisure. Bioactive fibre is a modified form of the finish, which includes

chemotherapeutics in their structure, i.e., synthetic drugs of bactericidal and fungicidal qualities.

These fibres are not only used in medicine and health prophylaxis applications but also for manufacturing textile products of daily use and technical textiles.

The field of application of the bioactive fibres includes sanitary materials, dressing materials, surgical threads, materials for filtration of gases and liquids, air conditioning and ventilation, constructional materials, special materials for food industry, pharmaceutical industry, footwear industry, clothing industry, automotive industry etc.

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Antistatic Finishes

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 Static electricity can cause many processing problems for textile materials, especially those made form hydrophobic synthetic fibres.

In most dry textile processes, fibres and fabrics move at high speeds over various surfaces which can generate electrostatic charging from frictional forces.

This electrical charge can cause fibres and yarns to repel each other, leading to ballooning.

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Anti static property can be brought out: By reducing the charge, By increasing the surface conduction power, By making the fibre hydrophilic.

Most of the antistatic finishes are based on the first mechanism ie., by reducing the charge and increasing the surface conduction.

Silicone emulsions, PE emulsions, PE Glycols, Poly Ammonium Quaternary Salts, Acrylic Polymers can be used for this purpose.

In fact the Silicone emulsion when used, produces antistatic property by reducing the friction between the fibres with added advantages of soil release property, softness and suppleness etc.,

Mechanism of Antistatic Finishes 

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METHODS OF APPLICATION

There are two methods of application of antistatic agents.

By incorporating non-durable antistatic agents into polymer during manufacture of synthetic fibres.

By applying either non-durable or durable antistatic agents, on the filament or yarn or fabrics. These are applied either by Exhaust method or by Pad – Dry – Cure method.

Some of the commercial antistatic agents for synthetic fibres are Cirrasol Pt (ICI), Ceramine R, ANS (Sandoz), Antista Oil, Antista D,M (Ahura chemical products), Antistatic Oil, Antista D (Hico products Ltd.,), Antistatin C, D and M (BASF).

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The textile products that are treated with antistatic finishes includes –

a)     Carpets for computer room.b)     Upholstery fabrics and airbags for automobiles.c)      Conveyor belts.d)     Filtration fabrics.e)      Airmail bags, parachutes.f)      Fabrics for hospital operating rooms andg)     Protective clothing for work with flammable gases,

liquids and powdered solids.

USES

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CREASE RESISTANCE FINISH

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CREASE RESISTANCE FINISH

The formation of crease is an undesirable property to the apparels.

So material has to be made either crease resistant or recovereable.

The objective of this finish is to keep the fabric flat and smooth and free from undesirable creases.

This is purely chemical and permanent finish.

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Mainly applied in cotton, rayon and flax. Wrinkle occurs due to the hydrogen bonds of the

cellulosic molecules in the amorphous region. Due to application of heat or moisture, the hydrogen

bond breaks and new hydrogen bond occurs at new dimension.

Therefore wrinkling can be reduced if the hydrogen bond formation can be reduced.

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The most commonly used cross linking agents are the resins.

The resins react with the OH groups of cellulose forming cross links which is durable & hence increases crease recovery thereby dimensional stability of the fabric.

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Advantages:

It imparts a smooth and quick drying property. It improves resilence, handle and draping quality. Increases strength of rayon in both wet and dry state. It becomes partially waterproof and rot proof Improves fastness to light and washing of many dyestuffs.

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Disadvantages:

It decreases the tensile strength and tear strength. It decreases the abrasion resistance. Gives unwanted harsh and stiff feel. It gives an unpleasant odour. It turns the fabric yelllow after chlorine bleaching.

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DURABLE PRESS

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Wash & Wear and durable press (permanent press) finishes are given using resin precondensates.

This kind of finish is not suitable where pressed in creases are required.

Inserted creases on this fabric disappear quickly during wear. For sharp retention of pressed in creases and freedom from

ironing the fabrics, the garments require durable press finish.

DURABLE PRESS

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The cross linking agents are first applied by padding. After padding, the fabric are made into garments or some

desired form. Then the Curing treatment is given to the fabric at a high

temperature in the form of garments. This finishing is called as Durable Press finishing.

The sequence of process of durable press finish

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This type of finish is generally used in garments making.

High concentration of resin and curing at high temperature for a

longer time are required for this kind of finish. DMDHEU is the resin which is used for this finishing. These finishes are achieved by similar techniques as crease

recovery finishes. DMEU or Ethyl Carbomates may also be used for durable press

finish.

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The resin should be fast to washing and should not affect the Light

fastness of certain dyes.

The main disadvantage of this finish is loss in strength and Reduction in

Abrasion resistance, because of the combination of high resin content, and

prolonged curing at high temperature.

Ionic and Non-ionic softeners are therefore added to the resin finishing

bath to minimize the loss in strength and abrasion resistance.

Emulsion of polyethylene, polyvinyl chloride, silicones etc; are also added.

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SHRINKAGE CONTROL

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SHRINKAGE CONTROL

Fabric is stable when retains original size & shape during use

and care Relaxation shrinkage—occurs during washing, steam

pressing or dry cleaning; most occurs during first care cycle Progressive shrinkage—continues at smaller rates for several

additional care cycles

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Cotton, flax, lyocell & HWM rayon exhibit relaxation

shrinkage. Regular rayon exhibits high relaxation shrinkage & moderate

progressive shrinkage. Wool exhibits moderate relaxation shrinkage & high

progressive shrinkage. Other properly set MF exhibit relaxation shrinkage & no

progressive shrinkage.

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Relaxation shrinkage finishes:

Knit fabrics shrink due to stitch elongation during manufacture—return to

normal size during laundering Minimized by overfeeding fabric between sets of rollers to induce lengthwise

shrinkage; loop drying; heat setting of thermo-plastic fibers. Woven fabrics shrink when wetting relaxes strain of manufacture—most

noticeable in filling direction. Compressive shrinkage used to maximize shrinkage.

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Progressive shrinkage finishes:

Thermoplastic fibers— Stabilized by heat setting; when properly set, have no progressive

shrinkage & little relaxation shrinkage.

Wool fibers— Surface coating—polyamide solution enables fibers to move

back and forth without entangling; controls shrinkage, pilling & fuzzing.

Halogenation—chlorine partially dissolves scales and reduces felting shrinkage.

Rayon fibers— Resins reduce fiber swelling & make it resistant to distortion.

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SOIL RELEASE

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INTRODUCTION

Soil release finish is a kind of finish which facilates the removal of soil during laundering under common household conditions.

Active wear and leisure wear are mainly treated with soil release finish.

Examples of apparels applied with soil release finish are industrial uniforms and napery etc.

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FACTORS AFFECTING SOIL RELEASE

Nature of soil- oily soil or particulate soil, hydrophobic or hydrophilic, liquid or solid.

Kind of fibres- Type of fibre, hydrophilic or hydrophobic, smooth or porous fibre surface.

Nature of textiles- Textile construction, yarn, fabric.

Effects of dyeing and printing- difference in binder films, residual hydrophobic dyeing auxillaries.

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CONTD…

Effects of other finishes- compatible with antistatic finishes, easy care finishes etc.

Non compatible with conventional repellent finishes and other finishes where hydrophilicity is determined to finish performance.

Washing conditions- Detergents, hydrodynamic flow in the washing machine.

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Making the fibers more absorbent (hydrophilic). Permitting better wettability for improved soil removal. Done by using hydrophilic finishes. Facilitates soil release during washing. Prevent soil redeposition. Also, reduces static charge by maintaining moisture on the

fabric surface. Thus soil attraction during wear can be reduced.

Advantages of soil release:

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MECHANISM OF SOIL RELEASE

Adsorption of detergents and absorption of water leading to:- rolly up soil Penetration of soil- fibre interface of by wash liquid. Solubilisation and emulsification of soils. Mechanical work leading to:- Hydrodynamic flow carrying away the removal soil. Fibre flexing to force soil from between th fibres Surface abrasion to remove soil physically. Swelling of finish to reduce inter fibre spacing.

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CHEMICAL MECHANISM

Increasing hydrophilicity, swelling of fibre and finish.

Some hydrophobicity (HLB value about 15). Electrostatic repulsion. Protective coating with ablative or sacrificial

finishes. Alkali treatment of polyester. Plasma treatment.

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CLASSIFICATION OF FINISHES

Carboxy based finishes Hydroxy based finishes Ethoxy based finishes Fluorine based finishes

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CARBOXY BASED FINISH

In this kind of finish composition is based on acrylic and methacrylic acid and ester copolymers.

This composition is taken in ratio to provide the proper blend of hydrophilicity and olephobocity required for soil release finish.

These products are usually pad applied in combination with DMDHEU cross linkers and provide soil release by a finish swell mechanism.

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CONTD…

N-methyol acrylamide react easily with DMDHEU during the finish curing step for increased laundering durability.

Finishes to be effective about 2.5% solids add-on of the soil release polymer is necessary.

Other caboxy compounds used are styrene-maleic anhydride copolymer and sodium carboxymethyl cellouse is used.

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HYDROXY BASED FINISHES

In hydroxy finish mainly starch is used which functions as a sacrificial treatment.

Other starch-cellulose compounds used for soil release agents include methyl cellulose, ethyl cellulose, hydroxypropyl starch,hydroxyethyl cellulose, hydroxypropylmethyl cellulose and hydrolysed cellulose acetates.

These finish must be applied in combination with a binder cross linking agents because these finish lack the laundering durability.

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ETHOXY BASED FINISHES

In this type of finish oxyethylene groups are used for soil release finish.

Products contain polyethylene blocks or ethylene oxide reaction products with acids, alcohols, amines and phenols etc.

Binding agents are used depending upon the laundering durability. Mostly done for polyester fibre. These products provide extremely durable soil release properties

for polyester fabrics either by exhaust or padding application with about 0.5% solid add ones.

These finish can be applied during dyeing process also.

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CONTD…

High soil release performance excellent softness and combinability with fluorocarbons finishes may be achieved by special silicon/polyalkylene oxide polymers.

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FLUROCARBONS BASED FINISHES

This kind of finish is very complicated. Proper choice of copolymer can be used In fibers to complete

this kind of finish. Dual action mechanism is illustrated in this kind of finish:- The hydrophilic blocks are shielded by the fluorocarbon

segments when dry presenting a repellent surface.

After immersion in wash bath the hydrophilic blocks can swell and actually reverse the interfacial characteristics of the surface yielding the hydrophilic surface necessary for soil release.

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CONTD…

Modified fluropolymers are pad applied to fabrics in combination with durable press cross linking agents to increase the durability of the finish.

Mixtures of both polymers types provide a common compromise between efficiency and cost.

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TROUBLESHOOTING

Any material deposited on the fibre surface that would reduce the hydrophilicity property must be avoided.

Softeners, lubricants must be investigated before applying in the fabrics.

The relative amounts of binders and cross linkers applied in the conjunction with acrylic copolymer soil release compounds must be carefully determined.

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FLAME RETARDENT FINISH

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INTRODUCTION

Flame retardant finishes provide textile with an important performance characteristics that is it stopped the propagation of fiber when it comes in contact with fire.

Flame retardant finish is a surface finishes and coating that inhibit, suppress, or delay the production of flames to prevent the spread of fire

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Provide textile with an important performance.

Needs of flame retardants Protection of consumer Fire fighter & Emergency personnel Upholstery and drapery protection The Military The Airline industry.

Importance of Flame Retardant Finish

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MECHANISMS

There are generally four types of mechanism:- First approach- In this method a heat sink on or in the

fibre by the use of materials that thermally decompose through strong endothermic reaction.

If enough heat is can be absorbed by these reaction the pyrolysis temperature of the fibre is not reached and hence no combustion takes place.

Example of this method are the use if aluminum hydroxide or alumina trihydrate and caco3 as fillers in polymers and coatings.

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CONTD…

Second approach- In this approach a material is applied that form an insulating layer around the fibres at temperature below the fibre pyrolysis temperature.

Boric acid and its hydrated salts function in this capacity.

When heated this low melting compound release water vapor and produce a foamy glassy surface on the fibre insulating the fibre from the applied heat and oxygen.

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CONTD…

Third approach- In this method the pyrolysis temperature is influenced to produce less flammable volatiles and residual char.

This condensed phase mechanism is seen in the action of phosphorous containing flame retardants.

Then it produces phosphoric acid through thermal decomposition , crosslink with hydroxyl containing polymers therby altering the pyrolysis to yield less flammable by products.

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CONTD…

Fourth approach- This is the approach of free radical reaction.

Materials in this act as gas phase mechanism include halogen compounds which during combustion yields hydrogen halides that relatively form long lived less reactive free radicals effectively reducing the heat available for perpetuating the combustion cycle.

This decreases the oxygen content by flame gas dilution.

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FLAME RETARDANTS FOR WOOL

One of the process of flame retardants for wool is “zirpo” which is based on hexafluro zincronate and titanate salts.

It is applied by exhaustion and pad process under acid condition at pH<3.

The finish is durable dry cleaning and water washing upto 40c at pH<6.

These finish can be combined with dyeing at pH<3. It is compatible with shrink resistant and insect

resistant.

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CONTD…

Another flame retardant treatment for wool is based on exhaustion of an anionic species with use of tetrabrmophthalic anhydride which hydrolysis to the carboxlic form during application.

Using TBPA at-10 on weight of fabric under acid condition provides effective flame retardancy.

This is durable to dry cleaning and mild laundering conditions.

TBPA is suspected to generate polybrominated dioxins under burning conditions.

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FLAME RETARDANT FOR POLYESTER

One of the most flame retardant finish for polyester is bromine contaninig phosphate ester, tridibromopropylphosphate (TRIS).

It is applied by both exhaustion and padding processes and provide excellent flame retardancy at reasonable add ons.

This method was banned because carcinogen is being formed.

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CONTD…

Another flame retardant for polyester is a mixture of cyclic phosphates used in a pad-dry-heat set process.

Heat set conditions of 190-210c for 0.5-2mins are adequate.

This product when applied at 3-4% add on can provide to a wide variety of polyester textiles.

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CONTD…

Another approach for duarable flame retardant finish for polyester is the use of highly brominated chemicals as topical finish.

Useful material is hexabromocylododecane (HBCD). To achieve durable flame retardancy fabric is padded

with 8% of a dispersion of this water insoluble material must be heated above 190c to form a film of a flame retardant on the fibre surface.

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FLAME RETARDANTS FOR NYLON

In this only additives to the polymer melt and tropical finish have been commercialized.

Phosphorous and bromine containing compounds are the most common.

Treatment is done with the condensation product of thiourea with formaldehyde and urea.

The flame retardancy is effect is done by lowering the melting point of nylon by 40c and allowing the fibre to drip away from the ignition source.

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FLAME RETARDANT TO OTHER FIBRES

Flame retarding for acrylic fibres is to copolymerise halogen containing monomers into the fibre.

Polypropylene fibres can be flame retarded with bromine and phosphorous containing additives to the polymer belt.

However high add ons are required and fibre properties are adversely effected.

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FLAME RETARADING FIBRE BLENDS

In order to flame retard natural/synthetic fibre blends high levels of flame retardants are required.

By using decabromodiphenyl oxide in combination with antimony trioxide a cotton/polyester blend fabric can be flame retarded.

In this 37% of add ons are required in addition to latex and softner .

The colour and hand of the finished fabric is altered and chemical costs are high.

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Water Repellent Finishes

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Water Repellant

Water Repellant finishes are which resist the penetration of water into the fabric but permits the passage of moisture or air.

If the fabric becomes very wet,water will eventually pass through.

The principle is that it is coated with the repellant chemical which permits the passage of air and vapour between the interlacing in fabric.

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Water and the other liquid remain on the surface in small bead rather than spreading out and getting absorbed.

The Chemicals used are silicones,fluorocarbons,paraffins etc.

Some chemicals used for water repellancy are also stain repellant.

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METHODS :--

The yarns are coated with water repellent material like wax.The water repellent do not permit the water drop to spread and penetrate.

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WATER REPELLENT FINISH:

METHODS:

A) USING METALLIC SALTS:PROCESS:

Pad the fabric with metal salts like Aluminium Acetate or Lead Acetate. Passing the padded fabric through Soap solution like Sodium Stearate. If necessary a little quantity of wax may be added. This method is not permanent.

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B) USING SILICONE EMULSION:They impart not only water repellency but also soft handle and improved draping qualities.

PROCESS:

Pad – Dry – Cure. If necessary, Resin maybe added in conjunction with silicone. Catalyst should be added for permanent durable finish. Eg., for catalyst, organo-Metallic salts. They are added just before the application. The pad bath contains Silicone, Resin, Emulsifier and a Catalyst.

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C) THE VELAN PF PROCESS:It imparts water repellency and a soft attractive finish. It is fast to washing, boiling soap solution, dry cleaning etc., It is a compound of Quaternary Ammonium Salt with Pyridine Base and a compound is formed with cellulose in the presence of Sodium acetate.

PROCESS:Pad – Dry – Cure – Soaping – Rinse, 1. Padding : 6% Velan PF + 3% Sodium acetate at 35 C, 2. Drying : 60 – 70 C, 3. Curing : 120 C for 2 – 3 mins. 4. Soaping : Soap – 0.2%, Soda – 0.1%,5. Temp – 35 C, 6. Time – 1 to 2 min. Any soap or other detergent left in the material will reduce its apparent Water

repellency.

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Application:

Textile materials: Raincoats Umbrellas Tarpaulins Swimming suits Diver suits etc.

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Water Repellent

Tarpaulins Diver Suit

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Shoe for military

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Water Proof Finish

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Water Proof Finish

Water proof finishes are those finishes which will not allow water to pass through regardless of the time exposure.

These finishes also adversely affect the comfort property as they limit the passage of air.

These finish is coated with a resin,wax and oil etc. It can also be coated or laminated with a film of

natural or synthetic rubber or plastic.such as vinyl or polyurethane.

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Traditionally, waterproof fabric was made by coating

(like animal fat, wax, vegetable oils). Nowadays, uses

polyvinylchloride (PVC) polymer.

Coated fabrics are, however, considered to be more

uncomfortable to wear than water-repellent fabric, as

they are relatively stiff and do not allow the escape of

perspiration of vapour.

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PRINCIPLE

‘A film on the surface of the fabric should be formed for the prevention of air and water’.

When a uniform coating of suitable substances such as rubber is produced on the surface of a fabric, the interstices between the warp and weft yarns are blocked by the continuous film or substance and both water and air will not pass through the treated fabrics.

It is a chemical finish.

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REQUIREMENTS:

The fabric should not become unnecessarily stiff and the fabric should have soil release or soil repellent property.

Condition: The finish should not alter the fastness properties or

dyed material, feel, strength etc., of the fabric.

It can be carried out by 2 methods,.

1. Hydrophobic substances are deposited on the cloth.2. The fabric itself becomes hydrophobic.

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CHEMICALS USED:

1. Vulcanized natural rubber,2. Oxidized oils of varnishes, 3. Polyvinyl chloro acetate, 4. Polyvinylidine Chloride, 5. Cellulose acetate, 6. Cuprammonium hydroxide solution.

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Water-Resistant fabrics shed water because of their weave or because they have been treated.

Heavily milled and raised wool fabric are densely woven cotton,nylon or polyester with a hydrophobic finish.

Resists penetration of water but is not waterproof. Resists penetration of water for a limited time depending

upon the lengthof exposure and force of water.

WATER RESISTANT

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