Identification of Cotton Fibre (Physical Test)

 

Advantages and Disadvantages of Printing Methods

 

BLOCK PRINTING

Advantages		Disadvantages
(1)	This method is simple and decorative method of printing.	(1)	This method involves much manual work.
(2)	Method is quite simple so any expensive equipment is not required.	(2)	Method is slow and therefore low output (production is less)
(3)	In this method, there is not any limit in repeat of size of style	(3)	Good skilled labors needed for multi color design in this method
(4)	Prints produced have great decorative value and stamp of craftsmanship.	(4)	Fine and delicate designs are hard to produce using this method

STENCIL PRINTING

Advantages		Disadvantages
(1)	The method is simple and cost effective	(1)	Good design is difficult to obtain in this method
(2)	Stencils can be made rapidly and can be used for small orders	(2)	The process involves manual work and is, therefore laborious
(3)	Colour combination is good in this method	(3)	Method is not suitable for large scale production
(4)	Any kind of colour can be used in stencil printing including oil colours and water colours; other methods of printing do not permit the use of such colours

ROLLER PRINTING

Advantages		Disadvantages
(1)	Large quantities of fabric at the rate of 914-3658m per hour can be printed	(1)	Not economical for short run of fabrics
(2)	Faulty joints or joint marks are absent in this method	(2)	In this method, difficult to produce blotch designs
(3)	Fine sharp outlines and good prints can be obtained which is difficult to get in block printing	(3)	Repeat of design limited to the size of the rollers
		(4)	Setup cost of roller printing m/c is high

FLAT SCREEN PRINTING

Advantages		Disadvantages
(1)	This method gives higher production	(1)	A big setup required for more number of screens
(2)	Printing with different repeat can be made easily	(2)	Prints with more colors may not be possible
(3)	Good print is obtained	(3)	Printing paste not evenly controlled
(4)	Sharp lines and features easily produced	(4)	Screen clogging may be there in fine areas
(5)	Blotch design can be printed by this method which cannot be printed by block or roller printing

 

ROTARY SCREEN PRINTING

Advantages		Disadvantages
(1)	Production of printed material by this method is the highest as compared to roller printing or automatic flat-bed printing method.	(1)	The method is not economical for short runs of the fabric due to high cost of engraving of the screens.
(2)	As many as 24 colours can be printed by this method but 8 to 10 colours can be printed easily.	(2)	The size of repeat of the design is limited to about 65 cm. which is less than that of a hand screen.
(3)	Joint markets which are perceptible in flat-bed and hand screen printing methods are totally absent in rotary printing.
(4)	Half tone effects and vertical lines can be produced very successfully by this method.
(5)	The prints produced are free from smudging effect which is quite severe in roller printing.

 

TRANSFER SCREEN PRINTING

Advantages		Disadvantages
(1)	The operation of transfer printing is very simple and does not require expensive machinery.	(1)	The process is mainly applicable to polyester material; the prints on other synthetic fibers like nylon or acrylic have poor wet fastness and those on polyester-cotton blends are skitter. The process is not applicable to natural fibers like cotton or silk as they are not thermoplastic and do not possess any affinity for disperse dyes.
(2)	No after-treatment of the printed material i.e.drying, washing, streaming, curing or developing	(2)	The colour range i.e. the number of dyes used for printing is limited.
(3)	No skilled labour or a colour chemist is required.	(3)	The cost of printed paper is high and its width is limited.
(4)	Faults do not occur in printing because the defects are rectified at the stage of paper printing itself; consequently the rejects are few.	(4)	The process is not economical for short runs of the fabric and designs on the pre-printed release paper cannot be modified last minute colour changes are not possible.
(5)	The machine requires considerably less space for installation than that required for conventional printing machines	(5)	Colours fastness to light of the printed material is low as compared to the fastness obtainable by the conventional method of printing
(6)	No need to store printed goods; the goods can be printed when required quantity
(7)	It is possible to print knitted goods and garments as also grey fabric (provide it is free from stains).

SMART TEXTILES (Introduction)

• Smart textiles are the textiles which sense and react to environment conditions or stimuli.

• Smart textiles are able to sense changes in their environment and can act upon predetermined ways.

• They work on three basic parts :- Sensors, Actuators and Units (Systems)

Sensors 

Sensor is a device that detects or responds to a physical or chemical change.

Actuators

Actuator converts energy into motion, releases substance, noise and many other ways.

• Smart textiles are classified in three categories:-

  

• 1. Passive Smart Textiles (Sensors):- They can only sense the environment conditions.

  Examples:- Optic fibre, Conductive Material, Thermocouple

  2. Active Smart Textile (Sensors & Actuators):- They can sense and react to the environment conditions.

  Examples:- 

  Type – I :- Chromatic materials, Shape Memory materials, Phase Change materials,   

                     Hydrogel and Membranes

  Type – II :- Luminescent materials, Photovoltaic, Electric textiles

  3. Very Smart Textiles (Units and Systems):- They can sense, react and adapt themselves accordingly.

  Examples:- Space suits, Thermo regulating clothing, Health monitoring apparel

  Types of Sensors:- 

  • Blood Pressure Measuring Sensor

  • Body Temperature Measuring Sensor 

  • Positive Temperature Coefficient (PTC)

  • Negative Temperature Coefficient (NTC)

  • Pulse Rate Measuring Sensor

  Materials used for Smart Textiles

  • Metal fibres

  • Conductive inks

  • Inherently conductive polymer

  • Optical fibre

  • Coating with nanoparticles

  • Organic semiconductor

  • Shape memory materials

  • Chromic materials

  Application of Smart Textiles

  • Health care

  • Life belt

  • Life jacket

  • Defence

  • Fashion and entertainment

  • Sports wear

  • Purpose clothing

  • Transport and automotive use

  
  

  Phase Change Material (PCM)

  It is a latent heat storage material, which can be integrated into textile structures, in numerous ways, as microcapsules.

  Examples:- Paraffin wax, Fatty acid, Hydrated solutions, Eutectics or organic and inorganic compound.

PROTECTIVE TEXTILES (Introduction)

• The clothing itself provides the protection rather than an individual textile material, but textile fabric is the critical element in all protective clothing and other protective textile products.
• As the safety barrier between the wearer and the source of potential injury, it is the characteristics of the fabric that will determine the degree of injury suffered by the victim of an accident.
• There has been a large increase in the hazards to which humans are exposed as a result of developments in technology in the workplace and on the battlefield, for example.
• The need to protect against these agencies is paralleled by the desire to increase protection against natural forces and elements.
• The dangers are often so specialized that no single type of clothing will be adequate for work outside the normal routine.

In order to be successful, designers need to work closely with quality assurance and production personnel as well as potential customers and users from the earliest stages of development.

The types of protective garments specifically mentioned in the literature are :

• Tents
• Helmets
• Gloves (for hand and arm protection)
• Sleeping bags
• Survival bags and suits
• Fire-protective clothing
• Heat-resistant garments
• Turnout coats
• Ballistic-resistant vents
• Biological and chemical protective clothing
• Blast-proof vests
• Antiflash hoods and gloves
• Molten metal protective clothing
• Flotation vests
• Military protective apparel Including  antihypothermia suits and ducted warm air garments
• Submarine survival suits
• Immersion suits and dive skins
• Life rafts
• Diapers
• Antiexposure overalls
• Arctic survival suits
• Ropes and harnesses

The types of occupation and activities for which protective garments and other products are made specifically mentioned in the literature are :

• Police
• Security guards
• Mountaineering
• Caving
• Skiing
• Aircrew (both military and civil)
• Soldiers
• Sailors
• Submariners
• Foundry and glass workers
• Firefighters
• Water sports
• Winter sports
• Commercial finishing and diving
• Offshore oil and gas rig workers
• Healthcare
• Racing drivers
• Astronauts
• Coal mining
• Cold store workers

Types of Protection

·         Flame retardant

o   Kermel® and Kermel® / Viscose fabrics for flight suits, station wear and turnout gear.

o   Nomex® for military applications

o   Molten Aluminum splash protective fabric.

o   Electrical Arc

·         Ballistic protection

o   p – Aramid woven fabric for hard and soft ballistic applications

·         Lint free antistatic

o   Continuous filament polyester / carbon fabrics

·         Medical textiles

o   Systemic and non-systemic antibacterial and antistatic fabrics for surgeons gowns, scrubs and warm up jackets.

·         Chemical protection

o   Liquid chemical protective fabrics

·         UV protection

o   Fabrics that offer a UPF rating for the wearer.

·         Industrial work wear

o   Component fabrics for chain saw protection

o   freezer suits

o   waterproof clothing

·         Military textiles

o   Uniforms

o   Parachutes

Classifications of Protective Textiles

Ø  Materials & Technologies

·         Processing technologies for specific protective clothing are different, the main processes generally include:

1.      Material manufacturing or selection;

2.      Producing fabrics and other related items;

3.      Finishing, and

4.      Clothing engineering.