Prepared By:MD.AZMERI LATIF BEG

ID: 142-32-257Course Title: Apparel Wash, Dyeing &

Finishing.Course Code: AWF-514

M. Sc in Textile EngineeringDepartment of Textile Engineering

Flocking is the process of depositing many small fiberparticles (called flock) onto a surface. It can also refer to thetexture produced by the process, or to any material usedprimarily for its flocked surface. Flocking of an article can beperformed for the purpose of increasing its value in terms ofthe tactile sensation, aesthetics, color and appearance. It canalso be performed for functional reasons including insulation,slip-or-grip friction, and low reflectivity. Besides theapplication of velvety coatings to surfaces and objects thereexist various flocking techniques as a means of color andproduct design. They range from screen printing to moderndigital printing in order to refine for instance fabric, clothes orbooks by multicolor patterns. Presently, the exploration of theflock phenomenon can be seen in the fine arts.

Flock Printing

These types of printing technique consist of the application of flock (very short fiber) to the surface of a fabric by means of an adhesive. The flock may be contained in the adhesive paste, may be dusted onto it, or applied electrostatically to hold it erect. This is used to print various small designs onto the fabric, such as dots and figures, especially on light-weight or sheer fabric. Flocking is defined as the application of fine particles to adhesive coated surfaces. Nowadays, this is usually done by the application of a high-voltage electric field. In a flocking machine the "flock" is given a negative charge whilst the substrate is earthed. Flock material flies vertically onto the substrate attaching to previously applied glue. A number of different substrates can be flocked including; textiles, fabric, woven fabric, paper, PVC, sponge, toys, automotive plastic.

A diagram of flocking textureThe majority of flocking done worldwide uses finely cut natural or synthetic fibers. A flocked finish imparts a decorative and/or functional characteristic to the surface. The variety of materials that are applied to numerous surfaces through different flocking methods create a wide range of end products. The flocking process is used on items ranging from retail consumer goods to products with high technology military applications.

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Flock Printing

Tiny particles of fiber are made to adhere to a fabric surface inconformance to a particular design. Rayon and nylon fibers aretypically used for flocking.

The ability of flocked fibers to withstand dry cleaning and/orlaundry depends on the adhesive. Adhesives with excellentfastness to cleaning processes are used.

Elegant appearanceA flock print has a velvety, fuzzy surface. The foil (0.5 mm) is somewhat thicker than flex, which causes the design to appear slightly elevated from the apparel and results in the plush feel. The colors have a soft glow to them.

Flock Print process

• This process involvesprinting of glue on thefabric first, applying thefiber flock on the gelprinted by keeping thefabric on special table(electro staticallycharged).

• It requires a little hightime for curing thannormal prints. 120seconds at 160C will besufficient for curing.

Printing technique consisting of the application of flock (very short fiber) to the surface of a fabric by means of an adhesive. The flock may be contained in the adhesive paste, may be dusted onto it, or applied electrostatically to hold it erect. Used to print various small designs onto the fabric, such as dots and figures, especially on light-weight or sheer fabric.

The foil (0.5 mm) is somewhat thicker than flex, which causes the design to appear slightly elevated from the apparel and results in the plush feel. The colors have a soft glow to them.

Flock Printing technique

Flock Fibres

Flock can be made from natural or synthetic materials such as cotton,

rayon, nylon and polyester. There are two types of flock - milled and

cut. Milled flock is produced from cotton or synthetic textile waste

material. Because of the manufacturing process, milled flock is not

uniform in length, and can vary from fine (0~ - 0.5 mm) to coarse (0.4 -

1.1 mm). Cut flock is produced only from monofilament synthetic

materials. The cutting process produces a very uniform length of flock.

Lengths can be obtained from 0.3 - 5.0 mm and 1.7-22 dtex in diameter.

(One dtex is the measurement of a fibre that weigh; one gram per 10,000

meters of length.) The fineness of the flock, length of fibres and

adhesive coating density determine the softness of the flocking. It should

be noted however, that fine or short flock is difficult to work with, since

it has a tendency to ball-up during processing. Milled cotton flock has

the advantage of being the lowest in cost and the softest, but has the least

abrasion and wear resistance. Rayon is a little bit better on wear

resistance and nylon is the best. For cut flock, rayon is the least

expensive with the least wear resistance.

Cut nylon is the best grade of flock and produces a good feel, but is also

the most expensive. Cut polyester is basically used for industrial

applications such as automobile window seals, glove compartments, and

roofing. Besides cutting or milling, flock manufacturing includes several

other steps. After cutting, the flock is cleaned of oils that accumulated

during processing. It is vat dyed to any number of colours, and then

chemically treated to enable the fibres to accept an electrical charge.

Since the fibres are all dielectric, a certain amount of conductivity must

be present for electrostatic flocking process to occur. When the process

is complete the fibres are spin dried and then oven dried to a specific

moisture content. Note that flocking fibres are never totally dried, since

moisture content adds to their conductivity. Finally, the flock is

packaged in moisture proof bags that maintain proper humidity.

According to end use flock two types

Stuffing flock(use for upholstery)

Coating flock(cut or ground fibers used as a surface on fabric by

adhesive.)

Flocking

In short, the flocking process involves applying short

monofilament fibres, usually nylon or rayon, directly on to a

substrate that has been previously coated with an adhesive. The

diameter of the individual flock strand is only a few thousandths of

a centimetre, and ranges in length from 0.25 - 5 mm. Adhesives

that capture the fibres must have the same flexibility and resistance

to wear as the substrate. The process uses special equipment that

electrically charges the flock particles causing them to stand-up.

The fibres are then propelled and anchored into the adhesive at

right angles to the substrate. The application is both durable and

permanent. Flock can be applied to glass, metal, plastic, paper or

textiles. Flock design applications are also found on many items

such as garments, greeting cards, trophies, promotional items, toys

and book covers.

Flock printing principle

For flock printing the fabric to be printed should smooth and as

compact as possible.

Step-1

Application of adhesive: Adhesive is applied to fabric surface by

squeezer, roller, screen or spray methods. Synthetic resin can be

serve as the best adhesive.

Recipe:

Paralac 67----40 parts

Paralac 11----10 parts

White spirit--34 parts

China clay---15 parts

Lead napthilate(3% solution)-0.8 parts

Cobalt(8% solution)—0.3 parts

Water--------------X parts

Step-2

Flock application: (Can be flat/right angle to the fabric surface)

Step-3Drying: Drying condition depends on particular bonding agent. Drying carried at 70c for 3-8 min. For apparel steam heated tunnel is suitable.Step-4Final treatment: Excess flocks from unprinted areas are removed by brushing and mechanical suction unit.

The Flocking Process

The process of flocking is fairly simple and easy. First a suitable adhesive is

applied to the surface to be flocked. The flock is then applied, penetrating the

surface of the adhesive to create the desired velvet finish.

Electrostatic flock applicators charge the flock particles which are then

attracted to the grounded surface that is to be flocked. Unlike puffer or blown

application methods which merely sprinkle a flock layer onto the surface,

electrostatic application ensures that the fibres all end up standing at right

angles to the surface resulting in a velvet finish.

Electrostatic flocking is used extensibly in the automotive industry for coating

window rubbers, glove boxes, coin boxes, door cards, consoles, and

dashboards. Rally cars usually have their dashes flocked to reduce reflections

and to provide an as new finished to a modified dash.

Flocking is proving successful in a number of artistic ventures including the

decoration of jewellery, ceramics and pottery.

Using suitable adhesives flock can be applied to an endless range of materials

including plastic, metal, wood, rubber and fiber glass.

Detailed Insight

Consumers are always looking for something different and unusual. Suppliers seek

the same thing - a special item or product that will increase their market share or

generate new business. An example of this might be the recent popularity of mixed

media garments in the marketplace. Developing something different is always a top

priority, then, and is the driving force behind the recent resurgence of printer

interest in learning about flocking.

Flocking for decoration is not new, of course; similar methods were used in the

Middle Ages to attach fibre dust to sticky surfaces. It was in the 1970s, however,

with the advent of improved technologies and adhesives, that flocking became a

popular decoration method. Then, in the 1980s and early 1990s the popularity of

flocking faded away and few printers used the process. Even so, while flocking is

not the most widely used decorating process, nor is it a well known decorating

technique, the average person is aware of its velvet or suede feel.

Over the last several years, however, inquiries about the process have begun to

increase, and flocking is once again in demand as a decorating method. Even

though flocking may not be most decorators' first choice process at present, it is

used widely in many industrial applications. Flocked surfaces reduce water

condensation, act as good thermal insulators, and have been used in the

automotive industry for years for such items as glove compartment boxes, door

mouldings and window trim.

Application Methods

Decorative flocking is accomplished by using one of four

application methods: electrostatic, beater bar/gravity, spraying and

transfers.

The electrostatic method is perhaps the most viable flocking

method, especially for the printer doing more than an occasional

flocking job.

Flocking material can also be sprayed using an air compressor,

reservoir, and spray gun similar to spraying paint. The resulting

finish using this method is similar to a thin felt coating, as most of

the fibres will be lying down in the adhesive. It is primarily used

when large areas require flocking. It is an untidy process, because

some of the flocking fibres become airborne.

Flocking is also applied by printing an adhesive on to a substrate,

and then rapidly vibrating the substrate mechanically, while the

flock fibres are dispensed over the surface.

Flock application by the vibration method.

Flock application by the electrostatic method.

The vibration promotes the density of fibres, which is critical to good

fibre coating, and causes the flocking fibres to adhere to the adhesive

and pack into a layer. This process is called a beater bar or gravity

flocking system and is basically a mechanical process. With this

process the flocking fibres are randomly adhered to the surface of the

substrate, and each fibre adheres to the adhesive at a different depth,

creating an irregular flocked surface. Since the fibres adhere to the

surface of the adhesive, rather than penetrate or imbed in it, some

fibre shedding occurs. Loose flocking fibres generated during

production also have a tendency to migrate, so many of these systems

are installed in a separate area to prevent fibre contamination of the

shop.

The most successful method to ensure a good dense coverage is a

combination of electrostatic flock application with the use of beater

bars to help increase the density of the coating.

Adhesives

A wide variety of flock adhesives are available, both single part

and two-part catalysed systems. Adhesives are generally water or

solvent based. Some are air drying, others temperature or

catalyst curing. Adhesives are usually applied by brush, roller,

spray or screen printing.

Flock BinderChemical: Acrylic EmulsionAppearance: Milky White liquidHigh Quality Flocking binder. Adhesives gives very soft and silky Feel.Flock Binders that are available in different shades and colors. It finds application in textile industry and used as an adhesive for the lamination of film to paper/fabric. Flock Binder is well known for its long lasting features and useful for variety of purposes.

Example:-K-87 is a self-crosslinking acrylic emulsion which combines softness and resiliency with durability to washing and dry cleaning. Cured films of K-87 exhibit superior ultraviolet light resistance. To achieve durability from K-87. Catalysts are not needed. Due to its various properties, it makes itself ideal for application.

Indofil is very well known for flock binder in India & BangladeshIndofil FBSV : premium flock binderIndofil FB SV plus: GOTS approved flock binderIndofil SVM 49 : Regular flock binder Indofil K-87: Premium flock binder for special requirementsIndofil NFBS: Flock binder

Screen Print of AdhesivesMany of the adhesives have the consistency of plastisol ink. Care should be exercised to

select a stencil emulsion or film that is compatible with the adhesive to be printed.

Proper application of the adhesive is the most important part of the process. A very

heavy deposit of adhesive is required, but at the same time the adhesive should not be

'squeegeed' through the substrate. Care should also be exercised not to apply a thin

coating. Less adhesive does not give proper adhesion characteristics for the fibres,

which will result in low wear resistance. In order to achieve the proper deposit of

adhesive, the screen should be made from a 24 to 43 threads/cm (60 to 110 threads/inch)

monofilament mesh. Tension should be at 20 N/cm. Extra face coats of emulsion on the

print side of the screen may be required for mesh counts greater than 36 threads / cm (96

threads/in). Printing should be off-contact, using a 65 durometer ball-nose squeegee. If

you experience difficulty getting the proper coverage, do not thin the adhesive to make

it more printable. This will only create a thinner deposit by allowing the adhesive to

soak into the substrate. A better solution is to slow the squeegee stroke down to allow

the adhesive time to flow through the screen and on to the substrate. The flock adhesion

can be tested by subjecting the substrate to the standard textile wash test. If the flocking

fibres come loose or fall off, the adhesive may be too thin or the adhesive was

improperly cured. If the adhesive is properly applied, then the curing temperatures

should be adjusted until the substrate passes the wash test. This is the only safe way to

ensure proper curing of the adhesive.

Electrostatic Flocking of Textiles

Electrostatic flocking equipment for T shirt and other textiles is available in

three configurations: an automatic carousel for multicolour flocking, a single

station flocking unit that usually attaches to one station of a garment press, or

a portable hand-held unit for lower volumes. The cost of the equipment varies

from hundreds or a few thousand pounds for hand-held units to tens or

hundreds of thousands of pounds for automatic multicolour systems.

All of the equipment operates using the same basic procedure, and is explained

by a law of physics stating that opposing electrical charges attract each other.

In flocking, the electrical charge is generated by the use of two electrodes: a

high voltage, direct current grid connected to a power generator, and a

grounded substrate. An electrostatic charge is generated that propels the fibres

at a high velocity on to the adhesive coated substrate. This causes the flocking

fibres to penetrate and imbed in the adhesive at right angles to the substrate.

This forms a high density uniform flock coating or layer. Controlling the

electrical field by increasing or decreasing either the applied voltage or the

distance between the electrodes and the substrate controls the speed and

thickness of the flocking.

Multi colour flocking techniqueFor high level flock prints, multi colour flocking is desired.There are several possibilities:a) Flocking and drying of one colour, then flocking of the second colournext to it (only possible with simple motifs, very time consuming).b) Flocking of one colour onto the entire motif space, drying, then flocking of the second colour onto the already existing flock layer, etc. (very time consuming, flock onto flock is not very stable and the flocked area is stiff).c) Textile printing of several colours and flocking of the last colour only (this can create some very interesting effects).d) Multi colour flock transfers (see special description).e) MC-technique. Here, the adhesive is printed in form of the entire motif and the flock is applied into the adhesive colour after colour through a screen stencil (fabric 15 S, metallized polyester screen. Very nice motifs are achieved by this method. However, a lot of equipment is necessary as a carousel is recommended to have the individual screens fixed in exactly the same distance of the 1.1 fold flock length suspended freely).

Multicolour flocking equipment has one print station for

applying the adhesive and multiple stations for applying the

flock. It uses a flat metal screen that is coated with an

emulsion and exposed with each of the design elements, the

same as it would be for screen printing. The flock is placed on

the metal screen, which acts as the high voltage electrode, and

a rotating brush precisely dispenses the flocking material.

When the screen is lowered to the proximity of the adhesive

coated substrate, the flocking fibres are propelled into the

adhesive, as determined by the stencil on the metal screen.

Since the electrostatic field strength is controlled, and because

the metal screen and the adhesive-coated substrate are brought

close together, the flocking material is prevented from

attaching to the adhesive except where the stencil is located,

regardless of the size of the adhesive coated substrate.

Hand held units the hand held units are comprised of a metal plate, a generator and a flocking head. The metal plate must be grounded, and it can be placed where convenient. It is the equivalent of the platen on a textile press. The generator creates the electrostatic charge, and is wired to a canister that contains the loose fibres. A metal screen is mounted halfway inside the canister opening. The open end of the canister is then passed over the adhesive coated substrate, drawing flock fibres from the canister through the screen. The electrostatic charge propels the fibres toward the grounded metal plate. The adhesive coated substrate intercepts the fibres and flocking occurs. The substrate is then cured in a conventional dryer, and the loose fibres are removed by shaking, vacuuming or by using compressed air. Operation of these units requires a degree of skill to obtain the desired results. If the flocking head is held too far from the substrate poor coverage of flocking fibres will occur.

The operator must also hold the unit perpendicular to the substrate to prevent the flocking fibres from imbedding in the adhesive at an angle other than perpendicular to the substrate. Hand held units are also messier than automatic systems and leave behind more fibres. Curing the flocking is also an area that needs to be investigated. Since few screen printers use water-based adhesives, they may not have the proper curing equipment. Water-based adhesives require the use of dryers that have multiple independent heating zones with changeable air flow rates. Even plastisol and catalysed adhesive may require additional time to fully cure.

Application EnvironmentHaving a controlled atmosphere for flocking operations is generally regarded as another essential ingredient for success. Ideally, the flocking area should have a relative humidity of 60% and a temperature of 20C (68F). A small variation in temperature or a change in the percentage of relative humidity can result in a 3 to 4 factor change in the conductivity or electrical sensitivity of the flock and the substrate. These changes will have an adverse affect on the process, and will result in flock balling, reduced adhesion and density of the flocking, and an excessive use of flock. Flocking fibres are very sensitive to humidity and temperature conditions.

When a new batch of flock fibres is opened, the fibres will give off or receive moisture based on the surrounding environment. Less than 30% relative humidity in the production area will lead to fibres that won't accept a charge. Relative humidity in excess of 65% causes the flock to stick together and flow poorly through the metal screen or plate. For best results the flocking operation should be located in an atmospheric controlled room. As stated earlier, in the adhesives section, to ensure that your flocked designs have received a proper cure, sample prints should be subjected to the standard textile wash test.

Flocking Machines & Flocking EquipmentM&R’s Machine company invented flocking machines and accessory flocking equipment simplify the application of screen printing flock and the cleanup of excess T-shirt flocking material. M&R flockers make it easy to add tightly-registered multi-color T-shirt flocking capability to most M&R automatic textile presses. They’re activated by the print carriage and they’re compatible with M&R’s print-start/print-finish feature, M&R’s patented Optical No-Shirt Detector, and M&R’s Skip-Shirt foot pedal. Unlike some competing T-shirt flocking machines, M&R flockers do not require printhead removal.

Use:A highly reliable and affordable device suitable for the flocking of especially small-lot products, textiles, small items, interior accessories, and the like.

Flocking is a value-added alternative decorating method for achieving that unusual look. It only costs slightly more than producing a standard screen print, and in conjunction with textiles, it is certainly less expensive than embroidery. Also with the advanced state of adhesive technology nearly any material can be flocked, making it easy to add new products to your textile production capabilities. Wallpaper, greeting cards, mouse pads, book and album covers, and posters can all be flock printed. The successful use of electrostatic flocking depends on tight control over the process and the environment. Detailed production records should be kept, so the process can be repeated. Retention of production samples is also an important factor for repeat jobs, product reliability, and quality control information. While the process requires the use of special equipment, with practice a quality product can be produced.

ConclusionFlocking is a value-added alternative decorating method for achieving that unusual look. It only costs slightly more than producing a standard screen print, and in conjunction with textiles, it is certainly less expensive than embroidery. Also with the advanced state of adhesive technology nearly any material can be flocked, making it easy to add new products to your textile production capabilities. Wallpaper, greeting cards, mouse pads, book and album covers, and posters can all be flock printed. The successful use of electrostatic flocking depends on tight control over the process and the environment. Detailed production records should be kept, so the process can be repeated. Retention of production samples is also an important factor for repeat jobs, product reliability, and quality control information. While the process requires the use of special equipment, with practice a quality product can be produced.

Reference:http://www.flocking.biz/process.htmlhttp://www.indiamart.com/classic-prints/textile-t-shirt-printing-services.htmlhttp://www.flocking binder.biz/process.htmlhttp://www. Textile flockung_e/flock motif.htmlhttps://www.spreadshirt.com/help-c1328/http://impressions.issshows.com/screen-printing-process/Flock-Printing-A-Closer-Look-8287.shtml#sthash.upROHSOS.dpufhttp://www.garmentprinting-120202065211-phpapp02