HI-TECH WET PROCESSING
(recent trends and issues)
© James Park
C. Col., FSDC., C. Text, FTI.
BACKGROUND
TEXTILES AND GARMENT PRODUCTION
– MATURE INDUSTRIES
MAJOR SECTORS OF THE GLOBAL
ECONOMY
FIBRE CONSUMPTION - 81 MEGATONNES
INCREASING USE OF POLYESTER
EMPLOYEES – 26 MILLION WORLDWIDE
MAJOR TECHNOLOGIES - LONG
ESTABLISHED
BUT
CONTINUOUS DEVELOPMENT
PARTICUALRLY IN WET PROCESSING
DRAMATIC CHANGE FROM:
PRODUCTION-LED (VERTICAL)
MANUFACTURING
TO
RETAIL-SPECIFIED MANUACTURING
(CONCEPT TO CONSUMER – C2C;
GLOBALISATION AND GEOGRAPICAL
CHANGES;
LONG SUPPLY CHAINS)
CHANGE HAS REQUIRED NEW CONCEPTS:
JUST-IN-TIME (JIT) PRODUCTION
WITH
RIGHT-FIRST-TIME (RFT) PROCESSING
AND
QUICK RESPONSE (QR)TO MEET CONSUMER
DEMANDS
(ESSENTIAL WITH LONG SUPPLY CHAINS)
BENEFITS OF MODERN CONCEPTS
Concept
Benefits
Quick response
(QR)
Reduction in stockholding
Meeting immediate demands
of customer
Just-in-time
(JIT)
Reduction in stockholding
Right-first-time
(RFT)
Necessary to give QR and JIT
Major financial savings
Improved quality and
productivity
COST COMPARISONS
Blind dyeing
Small addition
Large addition
Strip and re-dye
Cost
100
110
135
206
Productivity Profit
100
100
80
48
64
-45
48
-375
In addition :
- LOSS OF REVENUE AND PROFIT BY
REPROCESSING RATHER THEN NEW
BATCHES
- EFFECT ON DESIGNED CAPACITY
OTHER SAVINGS FROM RFT
PROCESSING
•reduction in processing time
•reduction in energy use
•reduction in water and effluent
•shortened lead times
•reduced waste
•better machine utilisation through
production planning
•reduced capital expenditure on
processing equipment
•reduction in dye and chemical
inventory and costs
IMPORTANT FACTORS FOR RFT PROCESSING
Factor
Starting
materials
Monitor
by lab
Purity of water
X
Substrate dyeability
X
Substrate preparation
Dyeing
process
control
Colour
control
Dye standardisation
X
Moisture content of dye
X
Control by SOP
Exht
CD
X
X
Weight of substrate
X
Weighing and dispensing of dyes
X
X
Weighing and dispensing of chemicals
X
X
Control of liquor ratio
X
Control of pH
X
Time/temperature profile
X
Control of liquor flow/machine speed
X
Control of liquor circulation
X
Selection of dyes
X
X
Behaviour of dyes in combination
X
X
Accuracy of laboratory dyeing
Accuracy of transfer to bulk
X
X
X
X
Batch to batch reproducibilty in bulk
X
Method of colour assessment
X
Determination of metamerism index
X
X
X
X
TYPICAL COST SAVINGS
Saving in total dyeing cost of 30% (ranges from 24 to 36%
depending on substrate type and dyeing method) for each
correction eliminated through RFT dyeing
Reduction in dye inventory to 25% of original
Reduction in dye purchases by 30% (ranges from 25 to
45%) by selecting least-cost formulations
Elimination of dyeing full to standards (10% of dye cost)
Reduction in reprocessing (typically from 4 to 1.5%)
Reduction in laboratory dyeing to achieve target colour
(typically 8 to 2)
Fabric savings due to colour sorting (10% of annual fabric
purchases)
NOT ALL WET PROCESSORS
WORLDWIDE HAVE YET
ACHIEVED THE FULL BENEFITS
OF RFT PRODUCTION
THE SUPPORT LABORATORY MUST
BECOME THE NERVE CENTRE OF
THE OPERATION
Dye evaluation, selection, testing,
QC
Development of application
methods
Database preparation/colour
matching
Substrate evaluation
Preparation of SOP
USE OF ENGINEERED COLOUR TEXTILE
STANDARDS
COLOUR MEASUREMENT
TECHNOLOGY:
WIDELY USED AND GIVES MAJOR
BENEFITS
GREATER USE REQUIRED OF:
COLOUR SORTING
ENGINEERED COLOUR STANDARDS
CONTROL TECHNOLOGY:
WIDELY USED FOR:
DISPENSING SYSTEMS
MACHINE/PROCESS CONTROL
GREATER USE REQUIRED FOR:
TOTAL MANAGEMENT TECHNIQUES
OTHER AIDS TO QUICK
RESPONSE
LATE STAGE PROCESSING:
- PACKAGE DYEING OF YARN
- FABRIC AND GARMENT DYEING
- PRINTING
ALTERNATIVE PROCESSING ROUTES
CUT AND SEW COTTON GARMENTS
FULLY-FASHIONED COTTON
GARMENTS
TEXTILE PRINTING
ACCOUNTS FOR 15% OF TEXTILE
PRODUCTION
(28 BILLION SQ METRES PER
YEAR – WITH 2.5% ANNUAL
GROWTH)
TRADITIONAL METHODS –
UP TO 20 WEEK SEQUENCE
COMPARISON OF ROUTES
HIGH PRODUCTION DIGITAL
TEXTILE PRINTING MACHINES
(2011)
Benchmarking varies between manufacturers
Usually 8 colour machines
Quoted speeds of 400 to 3000 m2/hour
Durst
Hangzhou Honghua
La Meccanica
Konica Minolta
MS Italy
Reggiani
Stork
Xennia Technology
Zimmer
ZIMMER COLARIS
DIGITAL PRINTING (2011):
NOW MATCHING PRODUCTION SPEEDS OF FLAT
SCREEN METHODS
APPROACHING SPEEDS OF ROTARY SCREEN
METHODS
CURRENTLY ABOUT 1% OF TOTAL PRINTING
PRODUCTION
FORECAST TO BE 2% OF PRINTING PRODUCTION
BY 2015?
DIGITAL-PRINTING (2012) :
DIGITAL-PRINTING WITH
PIGMENTS POSSIBLE
(PIGMENT PRINTING MORE THAN
50% OF MARKET)
PRODUCTION OF 7,200 sq m/hour
COMPLEX CRITERIA FOR DIGITAL
PRINTING INK SELECTION
DEPENDS ON : FABRIC TYPE
COLORANT TYPE
COMPONENT COMPATIBILITY
PRINTING HEAD
TYPICAL TESTING REGIME – 18 PARAMETERS
EVALUATES: COMPATIBILITY WITH PRINTING
ELEMENT
SHELF LIFE
INK FEED PERFORMANCE
IMAGE QUALITY AND FASTNESS
PROPERTIES
OTHER ISSUES AND PRESSURES ON
TEXTILE CHAIN
INCREASING PRESSURE DUE TO:
OCCUPATIONAL HEALTH
ENVIRONMENTAL SAFETY
SAFE WORKING CONDITIONS
FAIR LABOUR PRACTICES /SOCIAL
JUSTICE
SUSTAINABLE TECHNOLOGY:
PROCESSES WHICH DO NOT INCUR:
EMISSION OF GREENHOUSE GASES
THE USE OF NON-RENEWABLE
MATERIALS
GENERATION OF WASTE
RESTRICTED SUBSTANCES LISTS
(just a few examples)
AAFA
Adidas
C&A
Coats
Liz Claiborne
Decathion
Esprit
Gap
H&M
Hanesbrands
IKEA
Levis
M&S
Next
Nike
Nordstrom
S. Oliver
Otto
J.C. Penney
Puma
REI
Ann Taylor
Tesco
Timberland
VF Corp
PARTICULAR PROBLEMS WITH:
TRADITIONALLY CULTIVATED COTTON
(Preparation)
POLYESTER
(HT Dyeing)
(More than 80% of fibre usage)
NOT YET ENOUGH ‘ORGANIC’ COTTON
SUPERCRITICAL CO2 – WATERLESS DYEING
MACHINE
ScCOO DYEING
PILOT (PACKAGE)
MACHINE (1991)
FABRIC DYEING MACHINE
DYECOO SYSTEMS + NIKE
Needs : DYES + EQUIPMENT
Process :
WATERLESS
SAVINGS IN ENERGY,
CHEMICALS AND TIME
NOT TOXIC
TOWARDS THE ‘GREEN’ DYEHOUSE
•reduction in water consumption
•reduction in pollutants and
volume of discharged effluent
•savings in energy, including heat
recovery
•reduction in atmospheric pollution
•minimising waste
•health and safety of operatives
•elimination of prohibited
chemicals in consumer products
MEASURES TO REDUCE WATER
CONSUMPTION
Development of efficient standard operating procedures (SOP)
Following SOP exactly, assisted by automation
Installation of machines operating at low liquor ratios
Operating at minimum liquor ratio by processing full machine loads
Monitoring liquor levels, assisted by automation, to avoid overfilling
Improved production scheduling to avoid unnecessary machine cleaning and
downtime
Replace direct heating by heat exchangers to avoid liquor volume increases
Control rate of flow of cooling water through heat exchangers
Return cooling water from closed-coil systems
Use of water-soluble lubricants to eliminate separate scouring
Combine processes or use one-bath methods whenever possible
Avoid after treatment or excessive rinsing, especially overflow rinsing
Allow drainage time between rinses
Adopt counter-current rinsing methods in continuous processing
Reuse relatively clean rinsing water for processes not requiring high-quality
water
Partial purification and bath reuse
Total water purification and recycling
Digital printing techniques
IMPROVEMENT MEASURES
Area for consideration
Factors for improvement
Water
Use of low liquor ratios – machines fully loaded
Combining processes
Water re-use
Continuous preparation, including cold pad batch
methods
Treatment and water recycling
Insulation of pipes and vessels
Heat recovery from HT processes (heat exchangers)
Low temperature processing
Use of inverter-driven electric motors
Atmospheric control on stenters
Colour dispensary management – individual protective
clothing
Safety equipment on HT machinery
Elimination of hazardous or dusty chemicals
Elimination of chemicals and colour in waste water
Elimination of prohibited chemicals on consumer
products
Colour measurement technology
Following SOPs
Effluent
Energy
Pollution
Health and safety
Dye and chemical costs
INSULATION – INSULADD
COATING
EQUIPMENT UP-DATES
Parameter
Equipment improvements
Process
equipment
CPB preparation
Low LR/horizontal spindle package dyeing machines
Radio frequency (RF) drying
Low LR/pneumatic circulation jet dyeing machines
Modern stenter installation
Improved plant layout
Digital printing techniques
Process control, automation and robotics, management
Automated/robotised dye and chemical weighing and
dispensing
Colour measurement technology including digital colour
communication/distance QC
Size recovery
Caustic recovery and re-use
Recovery, recycling and re-use based on in-house effluent
treatment
Control
equipment
Chemicals
Water and
effluent
EFFLUENT TREATMENT AND WATER
RECYCLING
TREATMENT ALTERNATIVES
CASE HISTORY – COTTON AND SYNTHETIC
FABRICS
RAW AND TREATED
EFFLUENTS
CURRENT SUMMARY OF EFFLUENT
TREATMENT AND RECYCLING
MANY DYEHOUSES TREATING EFFLUENT – RELATIVELY
FEW RECYCLING TO OBTAIN MAJOR PAYBACK
SIMPLE FLOCCULATION WILL MEET CONSENT LIMITS –
HIGH CHEMICAL COST
CROSSFLOW MEMBRANES PROVIDE BEST QUALITY -95%
RECYCLING POSSIBLE
MEMBRANE FILTRATION WILL REDUCE COD, SUSPENDED
SOLIDS AND COLOUR
RIVER WATER QUALITY IS IMPROVING WORLDWIDE
WITH THE ABOVE.
IN SUMMARY:
WET PROCESSING IS A HIGH-TECHNOLOGY
ACTIVITY
SUCCESSFUL OPERATIONS DEPEND HEAVILY ON
A MODERN SUPPORT LABORATORY
COLOUR MEASUREMENT AND CONTROL
TECHNOLOGIES ARE WIDELY USED GIVING
MAJOR BENEFITS AND COULD BE EXPANDED
EQUIPMENT AND PROCESSES ARE AVAILABLE TO
MEET THE INCREASING DEMANDS AND
PRESSURES OF THE TEXTILE CHAIN
THANK YOU
FOR YOUR
TIME
AND KIND
ATTENTION