Textiles Exam 4

• Mechanical finishes

- involve specific physical treatment to a fabric surface to cause a change in fabric appearance

• Temporary finishes

- removed the first time an article is laundered or dry cleaned

Fulling

A permanent finish used on wool fabrics • Resultant fabric is smoother and more compact • Process is carefully controlled scouring or laundering to induce progressive felting shrinkage in wool fabrics

Blotch

A print in which the background color has been created by printing rather that piece dying A special variety of direct print Ground and pattern colors are printed onto a white cloth, usually in one printing operation

Calendering

A process of pressing or ironing a fabric at high speed and under high presser • Variations of calendaring depending on cylinder surface: Ie. Simple calendaring, Glazed calendaring

Solution Dyeing

Also called dope dyeing or mass pigmentation • Part of the process of manufacturing fibers • Coloring agent is added to liquid spinning solution of manufactured fiber and then extruded from the spinnerette • Solution dyeing is required when aqueous-dyeing is too difficult, e.g., because of heat sensitivity (modacrylic) or hydrophobic nature (olefin) • Solution-dyed colors is fade-proof, have outstanding colorfastness • Well suited for draperies and automotive fabrics not used for apparel fabrics Used when permanence of color over a long period is needed

Aesthetic Finishes

Calendering Fragrance • Fulling • Mercerization • Napping and sueding • Plisse • Shearing • Softening • Stiffening

Resins

Chemical group applied as wet finishes cause changes in the hand, drapability, and physical characteristics of textiles modify fabrics in the following ways: • Add stiffness to fabrics, Stabilize fabrics in shape • Yarns in fabric are stabilized and resist shrinkage • Fabrics become less moisture absorbent and thus dry more rapidly • Cause significant reductions in abrasion resistance, breaking strength, and tear strength

Color Features of Printed Fabric

Colorfastness • Wet-on-dry • Wet-on-wet

Metamerism

Condition, when two colors match each other under one light condition, but look different from each other in a diff light "Color Flare" used to indicate a fabric that has changed color because of change in light source Possible problem when two or more fabric types, each dyed by different dyers, come together to be used as matched items Critical in coordinated sportswear and ski jackets Ex: ski jacket constructed of nylon shell, polyester lining, acrylic cuffs, cotton zipper tape should have same shade for all components in sunlight and artificial light

Mercerization

Considered one of the most important chemical finishes for cotton • This finish imparts luster to cotton • Increases strength by 25% and improves dye affinity • Also enhances hand and fabric drapability • permanent finish applied prior to dyeing • Material is treated under tension with cold water and concentrated sodium hydroxide solution

Pretreatment processes

Consist of cleaning operations to rid fabric of soil and additives accumulated during weaving and knitting processes • Required before any dyeing, printing or finishing can be accomplished

Quilted Materials

Consists of insulating filler secured between two layers of fabric Insulating component of quilts may consist of Polyester fiberfill or batting Polyurethane foam Down The three layers are held together by sewing or bonding to prevent filler from shifting Most quilted materials are made by sewing machines Seams in quilted materials provide a source of heat loss Used in quilts and mattress pads, sleeping bags,

The Environment

Digital printing is more eco-friendly • Less energy and water used • Inks are water-based rather than solvent based • Designers can work remotely • Cost effective when printing fewer than 500 yards

Types of Prints

Direct Discharge Resist

The Environment

Dyeing is a focus of environmental concern Natural dyes can have a worse environmental impact than synthetic dyes

Stages of Dyeing

Dyeing is done during any stage in manufacturing a product Textiles may be dyed as: Fiber, Yarn, Fabric, Garments Stage of dyeing depends on the type of fabric or garment being produced and the intended end use

Top Dyeing

Dyeing of fiber before it is spun into yarn Top-fibers of wool from which shorter fibers have been removed Top is select long fibers used to spin worsted yarn

Stock Dyeing

Dyeing of fiber or stock before it is spun into yarn Loose, unseen fibers immersed in large vats containing dye bath, heated to proper temperature Used mostly for woolen materials for Heatherlike color effect Ex. Harris tweed, Woolen cheviot

Yarn Dyeing

Dyeing of yarns before weaving/knitting Used for multi colored designs like plaid or stripes Typical- yarn dyed fabrics Dyed in diff forms skeins-large loosely wound hanks(skeins) of yarns immersed in dye vats. soft lofty yarns, ex. hand knitting cashmere yarns, most costly yarn-dyeing packages package dyeing- yarn wound perforated spool/tube called many spools fit into dyeing beams- Entire warp beam is wound on perforated cylinder and placed in dyeing machine. most economical and used in manufacture of woven fabrics

Classes of Dyes

Dyestuffs- highly complex organic substances They combine chemically and physically with a textile fiber molecule Dyes affinity for a particular fiber, its ability to combine with a fiber and impart color to it Dyes in each class: Possess similar colorfastness characteristics Applied with similar techniques Applied at similar temperatures

Conventional or Aqueous Dyeing

Fabric cleaned to remove warp stitches , dirt Mixed and agitated for minutes to hours After dyeing, scoured with soaps and detergents Rinsed to remove excess under reacted dye Failure to remove excess dye causes crocking(poor initial wash fastness, rubbing off of colors after extensive wear) Depth of shade- darkness of color or lightness in dyeing Depends on quantity of dye used as ratio of fiber, yarn, fabric or garment weight

Duplex Prints

Fabrics in which both sides are printed Interesting effects can be achieved with reversible fabrics---Used in reversible sheeting

Digital Printing

Fastest-growing method of printing textiles • Accounts for only 1% of global market • Popular due to easy integration with other digital tools like Photoshop, Illustrator, and CAD systems • Designers can use digital printing to modify repeat size, create different color ways and print immediately • Advantages: • Minimal fabric waste • Energy cost reduction • Better aesthetic than rotary-screen printing • Capability of obtaining complex imagery using unlimited color • Disadvantage: Slow production rate • Primarily used for sampling, just-in-time production and mass customization • Sampling turnaround time drops from 6-8 weeks to 1-2 days

Drylaid

Fibers manipulated in dry state

Wetlaid

Fibers manipulated in wet state

Three systems for making screen prints:

Hand-screen printing- used by ancient cultures • Automatic-screen printing- also known as flatbed printing • Rotary-screen printing- widely used method, screens are reoriented from flat configuration to rotary configuration

Roller Printing

High-speed process, prints over 6,000 yards of fabric per hour • Design is put on fabric by copper engraved cylinders • Copper rollers can be engraved with very fine, delicate details with very close tolerances • Separate engraved cylinder is required for each color in the print • Considered uneconomical unless very large yardages are produced • High cost and long lead time for roller preparation and machine setup • Used for staple designs produced in large quantities for many seasons • Fine and closely detailed paisley prints are an example

Screen Printing

Involves the preparation of printing screen made from fine-mesh fabric of nylon, polyester or metal tightly mounted on a frame or rolled into a cylinder • Screen fabric is coated with a non-porous film. • Pattern areas of opaque film are removed, leaving fine mesh screen that will be the printed pattern • Most commercial screens are coated with a film • screen placed on top of the fabric to be printed and print paste is forced through the mesh area of the screen with squeegee • Each color in the print requires its own screen and a separate application the color • A three color print requires three separate screens and three applications of color to the fabric • Each color of the design must be precisely placed on the screen

Stitch Bonding

Mechanical bonding system with very high production rate sew or stitch yarns or fibers (webs) together into a fabric sewing fibers or groups of yarn together • Nowadays, made on warp knitting machines by knit-through technique

Pigment Prints

Most textile prints are produced with pigments direct prints made with pigments Process called dry printing (unlike printing with dyes, wet printing) Pigment prints can distinguished from dye prints by comparing the difference in stiffness between a design printed portion and a non-printed portion ----- Deep shades are likely to be stiffer than lighter shades least costly, Simple to apply, require least amount of processing, no steaming or washing Produce bright, rich colors and can be applied to all types of fabrics Good to excellent fastness to light and dry cleaning (widely used in curtains and drapes)

Special Dyeing affects

Multi-color or multi-shade effects can be created using yarn-dye or piece-dye method

Plissé

Name of the finish and the fabric produced by this finish • Permanent finish, produced on cotton by action of sodium hydroxide(printed to the fabric in form of a paste) • Fabric shrinks only where the sodium hydroxide is applied producing a puckered effect do not require ironing/cheaper imitation of seersucker

Fragarance

New technology can give textiles an aroma therapeutic effect • Various fragrances are available, including an odor eliminator that neutralizes unpleasant odors, suchas perspiration or smoke • Fragrances are enclosed in microcapsules and applied during finishing processes which rupture on movement as a result of rubbing with the skin • Skin moisturizers, vitamins or insect repellants can be contained in microcapsules and slowly released

Burn-Out Print

Not a print in the classic sense Involves printing with a chemical that destroy fiber in the pattern-design print area a hole in fabric results Ex- simulated yelled embroidery made with two or three roller print, one with fiber destroying chemical and other prints a pattern simulating embroidery stitching Used in low-cost summer blouses and cotton lingerie

Felt

Oldest known textile Scale like surface serrations of fibers become interlocked and entangled when subjected to heat, moisture and agitation • Felt is made directly from fibers treated in machines with felting action • Felt ranges from 50 to 100% wool, other fibers being cotton or rayon • Felt with higher wool content can be blocked and shaped more effectively • manufacturing-blended, carded, assembled in layers of desired thickness, moistened and passed through hardening machine, mechanically agitated and heated, and then finished •does not fray or ravel as it has no yarns, no grain • poor drape, low tensile strength, does not return to shape when unduly stretched, forms tears and holes that cannot be mended • Uses include banners, billiard table covers, padding, craft

Setting the Color in Screen and Roller Printing

Once printed, further treatment sets the color • Printing with dye (Wet prints) - To make the dyes combine with fabric, the printed fabrics are exposed to steam (aging), then washed with soap (to remove other substances), rinsed and dried. large quantities of water and heat energy • Pigment printing (Dry prints) - Fabric subjected to dry heat to set resin holding the pigment (curing). No further treatment is required. savings in water and energy costs.

Pigment Coloring

Pigments are different substances for coloring textiles • Pigments insoluble in water and do not unite or combine in any way with the textile fiber • Pigment particles are microscopic colored chips, that may be held on the surface of a fiber by resin binding agents • Pigments, like dyes, can be applied to fibers, yarns, and fabrics as solid colors or prints • Pigment color is mixed with resin binder and applied as resin/pigment mixture • For pigment to adhere to the fabric, the resin must be heated (curing) rapidly and economically • Have excellent color fastness, hence, used extensively on curtains and drapes

Hand Screen Printing

Printing done commercially on long tables • Screens are made of material stretched over frame • Print operator moves the screen frames by hand successively along the whole table, printing one frame at a time until entire fabric is printed • Rate of production ranges from 50 to 90 yards • Hand-screen printing is done on a lot of garment parts • A special niche of this printing is t-shirt making, either assembled or cut garment parts

Colorfastness

Printing fabrics is a surface treatment of the material • Laundering, dry cleaning, or abrasion wear off surface fibers, thus lighter colored or uncolored fibers emerge on the surface, making the material appear faded • Pigments particularly have poor crock fastness as they have no attraction for the fiber and just adhere to the surface. Have a harsh hand as well • Fabrics retain color longer if they are yarn or piece dyed rather than printed

Introduction to Printing

Printing is dyeing in a localized, patterned area • Early examples of printing date back to 3000BC • Development of blocks and stencils offered consistency to this early form of decoration • Textile printing uses same dyes and pigments applied to produce dyed fabrics • Same principle of specific dye classes having select fiber affinities and general fastness characteristics • When dyes or pigments are used, thickened with gums or starches to prevent wicking or flowing of print design. This thickened or viscous solution is called "print paste"

Engineered Prints

Prints that have distinct designs located in separate areas of fabric Ex- a designer wants a dress whose front and back both have blue and white polka dots and sleeve has blue and white stripes the textile designer engineers a print in which both polka dot and stripe elements are on same bolt of cloth Another type consists of printing on garment parts such as a pockets or collars Garment parts are printed by hand-screen or heat-transfer process

Strike-Offs and Color Matching

Problems of color matching, laboratory formulations and metamerism in printed fabrics are similar to that of dyed fabrics • Sample yards printed for approval by designer prior to mass production is called "strike off" • Process takes 6 to 8 weeks, is problem for rapidly changing high-fashion • New technologies reduces this time to few hours

Shearing

Process used to cut off surface fibers on fabrics • It makes the surface of napped fabrics and pile fabrics more uniform (uniform pile height)

NonWoven Textiles

Produced by bonding or interlocking of fibers Mechanical, Chemical , Thermal, Solvent or a combo First in 1942

Discharge

Produced through a 2-step process Step 1: fabric is piece dyed a solid color Step 2: design is printed onto fabric, contains a powerful bleaching agent that destroys the color of the background dye. Eg: "white discharge"- a white polka dot on a blue background "Color discharge" - bleach agent and a dye that does not react with bleach are mixed in same print paste Can be made with roller and screen print methods Very costly production, since precise control of reducing chemicals is required Recognizable, if the background color is same shade on the face and back of fabric and print design area is white or a different color or shade than the background

Methods of Printing

Screen-print method Roller-print method Heat-transfer printing Digital printing

Garment Dyeing

Simple t-shirt, basic sweater, pantyhose can't do it with more complicated fabrics, bc some garments use several diff fabrics Dyeing of completed garments Advantage is the ability to respond to quick changes in fashion and last-minute demand of retailers and consumers Tailored items cannot be dyed--may distort the garment Paddle Dyeing- stationary box with rotating paddle circulates garments within the machine Rotary Dyeing- large perforated cylinder containing garments rotates in closed cylinder with dye liquor

Softening

Some fabrics need to be softened to have better hand and drapability • Fabric softening is accomplished through mechanical (temporary) or chemical (durable) finishing procedures

Resist

Step 1: printing a pattern design on white fabric with a chemical or waxlike resinous substance that prevents or resists penetration of dyes Step 2: Piece dyeing the fabric Result is dyed background with a white patterned area, same as discharge prints, but method is reverse, not a popular method Used where a background color in a fabric cannot be discharged Performed as a craft or hand printing (such as batik) rather than on a production basis

Sueding

Sueding is a similar mechanical finish to napping • Sueding uses rotating cylinders with sandpaper like material

Color Formulations

Textile designer/colorist develops and chooses specific color for material Dyer or chemist matches designers color with proper dyes and pigments

Embroidery

The art of creating and producing raised designs or motifs on woven fabrics, paper, plastic, knitted fabrics (used rarely) • Designs are produced with needles and thread creatively • Traditionally hand, or machine-made • Eyelet is embroidery fabric with hole and stitches around hole to finish it Schiffli machines called Schiffli embroidery

Half Tone

The gradual shading of a pattern from light to dark in the same color • Appearance of two-color pattern can be created with one color • Roller printing and rotary-screen printing can produce halftones • Halftones in roller printing is produced by gradually increasing or decreasing the depth of copper engraving of the roller • Halftones in rotary printing is produced by gradually increasing or decreasing the density of screen perforations in the pattern

Colorfastness

The property of a dyed or printed textile to resist color loss or fading due to laundering, dry cleaning, sunlight, bleach, perspiration, environmental gases, swimming pool chlorine • Particular dyes may be colorfast to one condition but not to others • Colorfastness is governed by: • The particular dye class • The individual dyes within each class The fiber to which the dye is being applied

Napping

These fabrics are passed against rotating, bristled, wire-covered brushes • Overall effect is a fabric with a raised fiber surface • better insulation and softer hand • Used in blankets, sleepwear and winter clothing

Dyes and Pigments

Two main ways of imparting colors Dyes- treatment of textiles with chemicals in water solutions Pigments- insoluble colored particles made to adhere to a fabric Third process of coloring is part of manufactured fiber production called solution dyeing. Pigments are added to fiber solution before extrusion from spinnerette

Tufted Fabrics

Type of pile fabric • Machine tufting is performed by inserting extra yarns into an already-woven fabric of relatively open weave • Insertion is done using row of adjacent needles as wide as the material being made. • Tufted fabrics are made only in heavier weights • Almost all carpet is tufted

Flock Prints

Type of printing in which tiny particles of fiber called fiber flock are made to adhere to a fabric surface with a design Process involves printing the design on fabric with an adhesive (rather than dyes or pigments) and then exposing the fiber flock to the fabric The flock is held onto the fabric only on the portion where adhesive was applied Two types of flocking: electrostatic and mechanical Each yields its own distinct touch to the flocked surface Flocking includes most manufactured fibers, is A process of covering the entire fabric surface Used for shoes and clothing, imitation plush, handbags and belts, bedspreads, furniture, etc.

Color Management

Typical system has spectrophotometer- capable of analyzing color of sample computer(dyestuff inventory stored in the memory) Software enables system mathematically mix dyes to reproduce original sample shade

Wet-on-Dry and Wet-on-Wet Effects

Wet-on-Dry -The printing of a second color on top of previously printed color, when first color is moderately or fully dry. Second color completely covers the first color. Used only on hand-screen prints • Wet-on-Wet - Printing of a second color over the first color that is still wet. Second color is applied immediately after the first, the two becomes mixed and a third color is produced. The third color is referred to as fall on. • Print designers can create a three-color print with two screens or rollers

• Chemical finishes

applied to the fabric by padding, followed by curing or drying

Antimicrobial Finishes

called antibacterial finishes • Involves chemical agents that inhibit growth of bacteria and fungi • An important finish for items in contact with skin, such as underwear, diapers, shoe linings, socks, bed linens, surgical packs • These finishes are easily applied and durable to laundering and dry cleaning

Rotary Screen Printing

continuous process since the screens are cylinders • Fabric being printed is moved on a rubber belt under rotary-screen cylinders in continuous motion • Fastest method more than 120 yards per minute • Seamless, perforated cylinders are used • Largest rotary screens have circumference of 40 inches and maximum repeat size of pattern is more than 40 inches • Rotary screen can print more than 24 colors • It can print fine particles through screen mesh to produces effects like gold, silver, pearls etc • Also used to apply coating and laminates •Finishes like waterproofing, flame retardant and water repellant can also be applied in this manner

Lace Fabrics

decorative design • It is created with threads or yarns on a netlike, open background • most complicated of all textile making process • techniques like intertwining, knotting and looping of thread or yarns • delicate or heavy, handmade and expensive

Disposable Nonwoven

discarded after single or limited use Convenience and cost of throwing away is less than product cleaning and sterilizing Ex. headrests, filters, surgical gowns, diapers

Cross Dyeing

done in yarn, fabric, garment, made with two or more fiber types dyed in a single bath containing two diff dye classes Diff fibers blended in the same yarn produces stock-dyed effect If two kinds of yarns are used in warp direction, vertical stripes can be formed If two kinds of yarns are used in both warp and weft, plaids can be produced Quicker and economical than other dyeing methods to produce same effect

Manufacturing Nonwovens

drylaid Wetlaid Spunlaid

Piece Dyeing

dyeing of woven/knitted cloth most common method of dyeing poor penetration in heavy or densely woven, dye doesn't penetrate center of yarn

jet dyeing

fabric circulated in rope form through closed system on jet-flow of dye bath No pressure, little tension on material Delicate fabrics can be dyed

continuos dyeing

fabric transverses through entire dyeing process without stopping useful in dyeing blends like cotton and polyester

beam dyeing

fabric wound onto perforated cylinders dye bath forced through fabric layers fabric remains stationary used to dye lightweight open construction fabrics no stress and tension on fabrics tricot is often beam dyed

Functional Finishes

improve performance properties of fabrics • Usually relate to comfort, health or safety

• Functional finishes

improve the performance properties of fabrics

Direct

known as Application print Design is printed directly onto a white cloth Overprint is when print is applied to previously dyed fabric--design is considerably darker than the dyed backgroun////most common, Easy to recognize If background is white or has large portions of white and the printed design is a lighter shade on the back of the fabric than on the face If background color is same shade on face and back (piece dyed) and print is substantially darker than background, its an overprint

Warp Prints

known as ikat Involves printing the warp yarns of a fabric before they are placed on the loom for weaving Then, the fabric is woven with a solid color filling, usually white or sometimes one that contrast with the warp print used Results is a soft, shadowed, blurred design on fabric Found almost exclusively in high quality and costly fabrics

• Semi-durable finishes

last through many launderings or dry cleanings and many are renewable in home laundering or dry cleaning

• Durable finishes

last throughout life of article but effectiveness diminishes after each cleaning

Bonded Materials

layered fabric in which a face fabric is joined to a backing fabric with an adhesive that does not add to thickness of the combined fabric. Backing fabric is often tricot and face fabric can be any type of cloth. methods of production: • Wet-adhesive bonding - adhesives are applied to fabric • Foam-flame bonding - uses thin layer of polyurethane foam

Laminated material

layered fabric in which a face fabric is joined to a continuous sheet material Foam laminated fabrics use foam as the middle layer, intended for clothing insulation. Relatively lightweight and entraps dead air. Hotmelt method is an additional way of laminating. Desirable in outerwear

pad dyeing

machine called dye pad is used open width fabric pass through dye bath then through rollers where dye solution is squeezed into fabrics Causes flattening, degradation of fabric

• Aesthetic finishes

modify the appearance and /or hand or drape of the fabrics

jig dyeing

open width fabric passed through stationary dye bath Tension on material as it passes on rollers, degradation my occur Not used for stretch woven or knitted fabrics

Stone Washing, Acid Washing, and Cellulase

primarily used for denim • Stone washing - makes new clothes look used and old • Acid washing - bleaching process, also called "frosting" or "ice washing" • Cellulase - an enzyme that attacks cellulosic fiber, lightening the color of garment

Union dyeing

produces one solid color on fabric that has two or more classes of fiber dyer accomplishes this by using two or more classes of dye, each of the same color Ex. a solid color bed sheet composed of cotton and polyester can be dyed using direct dye for cotton and disperse dye of same color for polyester

Durable Nonwoven

reusable application Ex. Apparel interlining, carpet backing, subsoil covers for road beds

Spunlaid

thermoplastic fibers are blown onto a collection surface as they are extruded

Tone-on-tone effects

using one dye bath light and dark shades of the same color on fabric containing only one generic fiber E.g.- Deep red and light red colors on same piece dyed fabric is achieved by combining two different kinds of polyester in the same fabric Widely used in the carpet industry for producing tweed effect on piece-dyed carpets

• Permanent finishes

usually involve chemical change and do not alter throughout the life of the fabric

Heat Transfer Printing

• A process similar to decal transfers • A design is printed on paper with printing inks containing dyes of the disperse dye class. • The printed paper (called transfer paper) is then stored until ready for use by the textile printer • When fabric is to be printed , it is passed through a heat-transfer printing machine • This machine brings the printed paper and unprinted fabric together at high temperature, so dye sublimates and transfers onto the fabric • No further treatment needed • Disperse dyes are the only dyes that can be sublimated • Heat printing is used for printing garment parts (logos, emblems etc.)

Automatic Screen Printing

• Also called flatbed printing • intermittent process • Fabric being printed is moved to screen and then stops for the screen squeegee action (done automatically) • The fabric then moves on to the next screen • Rate of production is 500 yards/hour • Used for whole rolls of fabric only • Cut garment parts cannot be printed by this method

Bonded and Laminated Materials

• Both materials are layered structures with different constructions

Singeing

• Different pretreatment processes: burning off projecting fibers or filament splinters from fabric surface

Bleaching

• Different pretreatment processes: done in fabrics to be dyed in light and medium shades

Desizing

• Different pretreatment processes: fabric is treated with enzymes after scouring to remove warp starches

Carbonizing

• Different pretreatment processes: removes leaf particles and cellulosic impurities from wool

Boil-off

• Different pretreatment processes: similar to ordinary laundering (for cotton, cotton blends, silks and manufactured fibers)

Scouring

• Different pretreatment processes: similar to ordinary laundering (for woolens and worsteds)

New Developments

• Reduced amount of seconds, improved color control, faster changeover of machines, more efficient use of colorants, chemicals and water are the result • Waterless dyeing technologies are commercially available

Stiffening

• Some fabrics need to be made stiffer and more crisp to fulfill the intended use • Buckram, crinoline, lawn and voile are examples of such fabrics • Starch of various types are also used as a stiffening agent • Starch also adds to the body and weight of the fabric