Chapter 16

Environmental Conerns

-Almost every step can harm environment -very aware of situation -significant quantities of water and energy -quality of water supply -hazardous chemicals -changes are dictated by costs, regulations, and laws, liability lawsuits, and public awareness.

Important concerns in finishing(3):

-Conserving water -Reducing energy use -Reusing water

Water-Bath Finishing

-Finishing chemical is placed in a water solution and padded onto the fabric by immersing the fabric the solution and squeezing out excess liquid -Fabric becomes heavier (5x) -Moving and drying require a lot of energy -Was standard for years because water is good, readily available, and an inexpensive solvent. Issues with water usable, sustainability, water pollution, and environmental concerns, and energy costs.

Alternate/Further Prep: Mercerization

-Sodium Hydroxide (NaOH) -Increases luster, softness, strength and affinity for dyes and waterborne finishes, increases absorbency. -Used on cotton linen, and some HWM rayon and lyocell. -yarn merc: continuous process with yarn under tension passing through guide and squeeze rolls -Fabric merc: done on frame with rollers used for saturating the fabric

Enzymes as alernatives to other organic and inorganic chemcials are increasing. They are more sustainable because:

-function at lower temps, use less water and energy, require less wastewater, produce fabric with a softer hand and less damage -Choses to react with certain chemicals so they are smart/intelligent finishes

4)Cleaning

All grey goods must be cleaned to be made ready to accept any finish.

Foam Finishing

Alternative method to water bath. Uses foam rather than liquid to apply chemical -Low wet pickup and decreased amount of chemicals used. Low cost -Downside: since the amount of water in the process decreases, the uniform application of a finish decreases

1) Handling: Continuous Process vs Batch Process

Batch Process- relatively short length of fabric is processed as a unit at one time in a machine. Entire thing immersed in solution at same time. Not necessarily sustainable due to baths being thrown out after each cycle Continuos Process- longer pieces of fabric that move in and out of a solution. More economical, not as sustainable due to energy and water.

2) Singeing

Burns any fiber ends projction from the surface of the fabric -minimize pilling, roughness, dullness -passed between two gas flame bars to singe both ends at once

Renewable Finish

Can be applied by consumers or reapplied by dry cleaners Ex) Water repellant spray

Invsible

Cannot recognize. Consumers have hard time spending higher prices on fabric with these finishes bc they cant see Ex) wrinkke & soil resistant

Fiber Processing

Cotton fibers processed separately from polyester fibers bc of the difference in properties.

Finishing Steps for wool fabrics

Crabbing- sets. fabrics immersed in first hot water then cold and then passed between rollers. Decating- steam ironing.. smooth wrinkle free finish and loft hand Carbonizing- Sulfuric acids to allow for more level dying and Pressing- between metal steamed and pressed

1) Handling: Minimus

Describes the smallest quantity of a fabric a buyer can purchase from a mill. -Affected by how the fabric is handled. -Shorter the minimus the higher the cost

In single stage (combining finishing steps) preparation, ____, _____, and _____ occur in one step rather than three.

Desizing, bleaching, and scouring

Visible finish

Easy to recognize Ex)dyeing, printing, embossing

Computer Control of Finishing

Essential. -automatically correct processes -automatically correct fabric tension -Solutions -Temperatures -Built in menus -Make planning easer -Minimize environmental problems

Preparation Step 2: Fabrication

Fabric is woven, knitted, or created some other way.

Drying Stage: Heat Setting

Fabric placed on tenter frame and passed through an oven. Exposure time and temp are carefully controlled. -can set yarn twist, weave crimp, and wrinkle resistant

Drying Stage: Loop Drying

Fabrics are not tried on tenter frame by ton loop dryer without tension Ex) rayon, soft finish, towels, stretchy fabrics and knits

Yarn Processing

Fibers are aligned, blended, and twisted -dirt and soil removed from both poly and cotton -processing keeps them separate until well into the yarn production

Plasma Treatment

Finishing in its infancy. Changes the surface nature -Dry process

Routine Finishing= Preperation

Finishing steps required for most fabrics to prepare them for dyeing and special purpose aesthetic and functional finishes.

Convertors

Highly specialized companies that perform finishing for mills

Reworking Stage

Inspecting fabric for defects or flaws and repairing problems wherever possible. -Inspecting: moving fabric over inverted frame in good lighting. Mark flaws on selvege and record quality. Reparing: only when ecnomically smart choice. corrects flaws marked by inspectors. Then its ready!

Preparation Step 3: Pretreatment of Prep of Fabric

Key prep steps are desizing, scouring, bleaching, mercerization, and heat settings

Scouring: Scouring

Lanolin from wool

Durable Finish

Last the life of the product, but effectiveness diminishes Ex) wrinkle resistant

Permanent Finish

Lasts the lifetime of item Ex) Mercerization

Temporary Finish

Lasts until the item is washed or dry cleaned Ex) Simple calandering

Drying Stage: Calendering

Mechanical finishing operation performed by a series of rollers where the fabric is passed through. -Simple, friction, moire, schreiner, and embossing.. each type produces a different finish -Simple calandering: smooth flat ironed finish.

Combining Finishing Steps

Minimizes space, chemicals, energy, water, and cost.

1) Handling: Open Width vs Tubular/rope

Open width- fabric width where fabric is held out to its full width of tenter frame Tubular/Rope-fabric allowed to roll and fall on itself to form a tube -tube can cause irregularities but its more economical -heavy weight fabrics don't use cause tube marks set in

7)Whitening: Bleaching

Process of whitening fibers yarns or fabrics by removing irregular naturaul color. Either acidic or alkaline. Not all fibers can use the same bleach. -Peroxide bleaches: common commercial bleaches -Peracetic Acid Bleaching: more sustainable

1) Handling: Run

Quantity of fabric receiving same processing at the same time -length of run increases, cost decreases (so mills prefer to work with longer fabric)

6)Scouring

Removal of foreign matter or soil from fabric. Usually involves detergens and alkaline solutions & can be repeated

3)Desizing

Sizing added to warp yarns is removed. Needed with wovens -needed to bond to filling and warp yarns -high energy and water waste use

Mill-Finished Fabrics

Sold and used without further finishing. May be sized before they're sold

Solvent Finishing

Solvent used to mix into solution -Decreases water pollution and energy costs -Not as popular as foam bc of solvent cost, evnrion concerns, health problems, regulatory concerns, ect,

7)Whitening: Optical Brighteners

Used to whiten off white fabrics. Not bleaches, but fluorescent whitening compounds. -Work best when used with bleach -Can be used without affecting fabric luster -Added to spinning solution sometimes to manu fibers

Special Purpose finishes

Usually follow dyeing to avoid interfering with fiber dye absorption.

Preparation Step 1: Sizing (slashing)

Warp yarns are treated before being threaded into the loom for weaving. Usually wound into a creel and coated with mixture of natural starches to resist abrasion and tension of weaving. -Natural starch is main ingrediant -adds protective coating to yarn to obtain optimal weaving efficiency, increase yarn rigidity, and decrease yarn hairiness

Coloration Stage

Where color is generally added

Ammoniating Finishes

alternative to mercerization used on cotton and rayon. Treat with weak ammonium solution at high temps.

Rinsing has seen significant:

amount of change due to combining steps.

Finish

any process done to to fiber yarn or fabric either before or after fabrication to change the appearance, the hand, or the performance. All finishing processes add to cost & time of end produce

Drying Stage: Tentering

applies crosswise and lengthwise tension to fabric while it dries. Its purpose is to meet specifications for width and width uniformity and warp and filling found. -overfeeding to reduce overstreching -marks or clips can show on selvege -Skew and bow off grains can be eliminated by proper tentering and are a result of poor tentering

Bleaching is almost always done ___ dyeing

before

Coloration is usually done ____ finishing and reworking

before

Ultrasonic energy

being used as an alternate form of energy

Improved performance is a ______ for all finishes.

benefit

Slack mercerization

cotton fabric is dipped at low tension in to a weaker caustic soda solution for a shorter time before neutralizing and washing.

Gray (Grey, greige, loom state) Goods

fabrics that have been produced but have received no wet or dry finishing operations... regardless of color! ex) print cloth, soft filled sheeting (only grey goods) lawn, broadcloth, sateen (finished fabric names)

Some Converted Goods retain their _____ name

grey good

Scouring: Degumming

gum from silk

Converted/Finished Goods

have received wet or dry finishing treatments i.e bleaching, dyeing, embossing.

Continuous open width processing is used for:

heavyweight blend fabrics

Cotton requires _____ preparation of of any fiber.

most

1) Handling

physical form of the fabric during finishing. -how its handled is influenced by width length and fabrication

Pickup

the amount of liquid or chemical a fabric absorbs during finishing

5)Bio-Polishing

use of cellulase enzyme treatment to remove surface fuzz from spun yarns of cellulose or cellulose blends. -permanent finish -colors look brighter to less fuzz and more smoothness -can be used instead of singeing

Scouring: Kier boiling off

wax from cotton