Basic Textiles VI
PRINTING
Printing: application of color to a textile material in a design or pattern.
Localized dyeing. Each different color is placed on fabric individually.
Print pattern: design registration.
Color clarity: color is uniform in depth and consistent in hue.
Pattern flushing/wicking: when color of pattern run or wick into each other.
Modern printing processes print paste is applied only on top side of fabric.
Fabric preparation is important for maximum penetration best color fastness
properties.
Types of printing processes
- Flat bed screen printing (popular)
- Rotary screen printing (popular)
- Engraved roller printing
- Heat transfer printing (also known as sublimation or iron-on printing)
- Digital printing
PRINTING PROCESS STEPS
These steps are for flat screen, rotary screen and engraved roller printing
processes = wet printing.
1. Preparation of fabric
2. Preparation of print paste
3. Printing of fabric
4. Drying
5. Fixation of dyestuff
6. Washing-off
Print paste consists of thickened solution containing textile dyes or pigments,
also auxiliary chemicals. Dyes chosen on fiber content of fabric. Pigments are not
fiber type specific. Pigments must contain binder that glues pigments to textile.
Fabric is printed and then dried to prevent smearing of print design. Thickener
holds dye/pigment in place until color is fixed.
Fixation requires steamer of high dry heat oven. For pigments high
temperature dry heat oven.
When color is fixed, fabric is washed to remove left-over ingredients. Normally
only dye or pigment-binder is left.
PREPARATION CLOTH
, Basic Textiles VI
Singeing or shearing / desizing / mercerization / bleaching / scouring.
PRINTING PASTE
Choosing colorant print brightness, fabric luster,
fabric air permeability.
Dyes or pigments?
Dyes Pigments
Price Expensive Less expensive
Material Fiber specific Not fiber specific
Brightness Varying Varying
Fastness properties Varying Varying
Negative impact feel Little to none Binders/glue can stiffen
product fabric
Popularity Popular Lower quality
Majority of fabric blends are printed with pigments.
Thickeners
The resistance of a fluid to flow (thickness fluid). Most crucial for print paste
formulation. Control viscosity or flow properties of the paste. control definition
and clarity of print image. Print design does not flush or wick into each other.
In screen printing thickeners shear thin.
Thickeners must be compatible with dyes or pigments used and with fiber
content of fabric.
Controlled by: temperature, pH and electrolyte concentration.
Sequestrants
Specialty chemicals that tie up any metal ion contaminants which might be
present in process water used in print paste formulation. Metal ions can cause
coagulation issues. Don’t use too much because pollution load can increase on
waste stream.
Dispersing agents
Chemicals that help promote uniform mixing of various chemicals together. Help
dyes or pigments penetrate deep into the yarn bundle.
PRINTING
Printing: application of color to a textile material in a design or pattern.
Localized dyeing. Each different color is placed on fabric individually.
Print pattern: design registration.
Color clarity: color is uniform in depth and consistent in hue.
Pattern flushing/wicking: when color of pattern run or wick into each other.
Modern printing processes print paste is applied only on top side of fabric.
Fabric preparation is important for maximum penetration best color fastness
properties.
Types of printing processes
- Flat bed screen printing (popular)
- Rotary screen printing (popular)
- Engraved roller printing
- Heat transfer printing (also known as sublimation or iron-on printing)
- Digital printing
PRINTING PROCESS STEPS
These steps are for flat screen, rotary screen and engraved roller printing
processes = wet printing.
1. Preparation of fabric
2. Preparation of print paste
3. Printing of fabric
4. Drying
5. Fixation of dyestuff
6. Washing-off
Print paste consists of thickened solution containing textile dyes or pigments,
also auxiliary chemicals. Dyes chosen on fiber content of fabric. Pigments are not
fiber type specific. Pigments must contain binder that glues pigments to textile.
Fabric is printed and then dried to prevent smearing of print design. Thickener
holds dye/pigment in place until color is fixed.
Fixation requires steamer of high dry heat oven. For pigments high
temperature dry heat oven.
When color is fixed, fabric is washed to remove left-over ingredients. Normally
only dye or pigment-binder is left.
PREPARATION CLOTH
, Basic Textiles VI
Singeing or shearing / desizing / mercerization / bleaching / scouring.
PRINTING PASTE
Choosing colorant print brightness, fabric luster,
fabric air permeability.
Dyes or pigments?
Dyes Pigments
Price Expensive Less expensive
Material Fiber specific Not fiber specific
Brightness Varying Varying
Fastness properties Varying Varying
Negative impact feel Little to none Binders/glue can stiffen
product fabric
Popularity Popular Lower quality
Majority of fabric blends are printed with pigments.
Thickeners
The resistance of a fluid to flow (thickness fluid). Most crucial for print paste
formulation. Control viscosity or flow properties of the paste. control definition
and clarity of print image. Print design does not flush or wick into each other.
In screen printing thickeners shear thin.
Thickeners must be compatible with dyes or pigments used and with fiber
content of fabric.
Controlled by: temperature, pH and electrolyte concentration.
Sequestrants
Specialty chemicals that tie up any metal ion contaminants which might be
present in process water used in print paste formulation. Metal ions can cause
coagulation issues. Don’t use too much because pollution load can increase on
waste stream.
Dispersing agents
Chemicals that help promote uniform mixing of various chemicals together. Help
dyes or pigments penetrate deep into the yarn bundle.
