Screen Printing
Involves the preparation of printing screen made from fine-mesh screen fabric
Rotary-screen printing-
widely used method, screens are reoriented from flat configuration to rotary configuration
Hand-Screen Printing
Printing done commercially on long tables
Screens are made of material stretched over frame
Hand-screen printing is done on a lot of garment parts
A special niche of this printing is t-shirt making
Automatic-Screen Printing
Fabric being printed is moved to screens on wide, rubber belt
Rate of production is 500 yards/hour
Used for whole rolls of fabric only
Rotary-Screen Printing
Fabric being printed is moved on a rubber belt under rotary-screen cylinders in continuous motion
Rotary-screen printing can print fine particles through screen mesh
This produces effects gold, silver, pearls, or the like
Roller Printing
High-speed process, prints over 6,000 yards of fabric
Considered uneconomical unless very large yardages are needed
Setting the Color in Screen and Roller Printing
Once printed, further treatment sets the color
Printing with dye: expose printed fabric to steam (aging) - "wet prints"
Pigment printing: Fabric subjected to dry heat to set resin holding the pigment - "dry prints
Heat-Transfer Printing
A design is printed on paper with printing inks containing dyes
A process similar to decal transfers
Disperse dyes are the only dyes that can be sublimated
Heat printing is used for printing garment parts
Advancements in the Print Industry
Printed textiles are less than 15% of textile industry
Printing industry is challenged with changing fashion trends
Printing industry is confronted with technology advancements
Digital Printing
Fastest-growing method of printing textiles
Accounts for only 1% of global market
Used for sampling, and mass customization
Typical digital tools: Photoshop, Illustrator, and CAD systems
Advantages:
Minimal waste
Energy cost reduction
Better aesthetic than rotary-screen printing
Capability of obtaining complex imagery using unlimited color
Disadvantages:
Slow production rate
The Environment
Digital printing is more eco-friendly that other methods
Less energy and water used
Inks are water-based rather than solvent based
Designers can work remotely
Color Features of Printed Fabrics
Many color features of printed features should be examined:
Colorfastness
Wet-on-dry
Wet-on-wet
Color matching
Colorfastness
Printing fabrics is a surface treatment of the material
Laundering, dry cleaning, or abrasion wear off surface fibers
Fabrics retain color longer if they are yarn or piece dyed rather than printed
Wet-on-Dry and Wet-on-Wet Effects
The printing of a second color on top of previously printed color
First color has to be moderately or fully dry
Third color is referred to as fall on
Halftone
The gradual shading from light to dark in the same color
Appearance of two colors can be created with one color
Roller printing and rotary-screen printing can produce halftones
Strike Off and Color matching in Printed Fabrics
Sample yards printed for approval by designer: "strike off"
Process takes 6 to 8 weeks
A problem for rapidly changing high-fashion
Direct Prints
When the design is printed directly onto a white cloth
Also known as an application print
Overprint is when print is applied to previously dyed fabric
Discharge Prints
Produced through a 2-step process
Step 1: fabric is piece dyed a solid color
Step 2: fabric design is printed onto fabric
Can be made with roller and screen methods
Very costly production
Resist Prints
Involves a two-step procedure
Step 1: printing a pattern design on white fabric with a chemical substance
Step 2: Piece dyeing the fabric
Resist printing is not a popular method
Pigment Prints
Most textile prints are produced with pigments
Pigment printing is referred to as dry printing
Pigment prints are slightly stiff
Pigment prints are the least costly type of print to produce
Pigment prints lose color gradually
Special Types of Prints
Special prints are not in widespread use
Special prints:
Blotch prints
Flock prints
Flocking
Warp prints
Burn-out prints
Duplex prints
Engineered prints
Blotch Prints
A print in which the background color has been created by printing rather than piece dyeing
A special variety of direct print
Blotch prints sometimes have large background color areas that are not covered with full depth of color
Flock Prints
Type of printing in which tiny particles of fiber are made to adhere to a fabric surface with a design
Two types of flocking: electrostatic and mechanical
Flocking includes most manufactured fibers
Flocking
A process of covering the entire fabric surface
Used for shoes and clothing, imitation plush, handbags and belts, bedspreads, furniture, etc.
Warp Prints
Involves printing the warp yarns of a fabric before weaving
Also known as ikat
Found almost exclusively in high quality and costly fabrics
Burn-Out Prints
Not a print in the classic sense
Involves printing with a chemical that destroy fiber in the pattern-design print area
Used in low-cost summer blouses and cotton lingerie
Duplex Prints
Fabrics in which both sides of fabric are printed
Used in reversible sheeting, table covers, and reversible jackets
Engineered Prints
Prints that have distinct designs located in separate areas of fabric
Garment parts are printed by hand-screen or heat-transfer processing
Permanent finishes
usually involve chemical change
Durable finishes
last throughout life of article
Semi-durable finishes
last through many launderings or dry cleanings
Temporary finishes
removed the first time an article is laundered or dry clean
Pretreatment Processes
Consist of cleaning operations to rid fabric of soil and additives
Do not technically qualify as textile finishes
Different pretreatment processes:
Desizing
fabric is treated after scouring if warp starches are present
Carbonizing
removes leaf particles and cellulosic impurities
Singeing
burning off projecting fibers or filament splinters
Bleaching
fabrics dyed in light and medium shades
Resins
Chemical group applied as wet finishes
Resins cause changes in the hand, drapability, and physical characteristics of textiles
Resins modify fabrics in the following ways:
Add stiffness to fabrics
Stabilize fabrics in the shape of the resin
Yarns in fabric are stabilized and resist shrinkage
Fabrics become less moisture absorbent and dry more rapidly
Cause significant reductions in abrasion resistance, breaking strength, and tear strength
Aesthetic Finishes
Change the appearance, drapability and hand of fabrics
Aesthetic finishes:
Calendering
Fragrance
Fulling
Mercerization
Napping and sueding
Plisse
Shearing
Softening
Stiffening
Calendering
to change the look of a fabric
Fragrances
New technology can give textiles an aroma therapeutic effect
Fragrances are enclosed in microcapsules
Applied during finishing processes
Fulling
A permanent finish used on wool fabrics
Resultant fabric is smoother and more
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
Napping and Sueding
Mechanical finish of woven or knitted fabrics
These fabrics are passed against rotating, wire-covered brushes
Overall effect is a fabric with a raised fiber surface
Napped fabrics are subject to pilling
Sueding is a similar mechanical finish to napping
Sueding uses rotating cylinders with sandpaper like material
Pliss�
A finish produced on cotton by action of sodium hydroxide
Pliss� fabrics usually do not require ironing
Pliss� is a cheaper imitation of seersucker
Shearing
Process used to cut off surface fibers on fabrics
Softening
Some fabrics need to be softened to have better drapability
Fabric softening is accomplished through mechanical or chemical finishing procedures
Stiffening
Some fabrics need to be made stiffer and more crisp
Fabric stiffening is done with several chemical finishes
Stiffening finishes are: buckram, crinoline, lawn, and voile
Stone Washing, Acid Washing, and Cellulase
Garment finishing processes primarily used for denim
Stone washing
makes new clothes look used and old
Acid washing
bleaching process with the effect of "frosting
Cellulase
an enzyme that attacks cellulosic fiber, lightening the color of garment
Functional Finishes
Finishes that improve performance properties of fabrics
Flame resistent
Most textiles burn if ignited
Flame-resistant finishes are applied as wet finishes
Depending on chemical used, they are either dried or cured
Potential negative results:
Stiffening and loss of drapability
Significant strength loss
Loss of finish in laundering
Ineffectiveness when laundered in household bleach
Shrinkage-Control Finishes
A finish that prevents shrinking in apparel
Relaxation shrinkage
occurs when fibers and yarns are under tension
Progressive shrinkage
occurs each time a fabric is laundered