FABRIC SCIENCE II
CLASS ACTIVITY
Bachelor Of fashion Technology (Apparel Production)
Department of Fashion Technology National Institute of Fashion Technology, Gandhinagar,
2020
Under the Guidance of Submitted by:
Ms. Ettishri Rajput Daljit Singh
(Assistant Professor Sanskar Dhankar
Department of Fashion Technology
NIFT Gandhinagar, Gujrat)
Sanforization
Sanforization is a process of pre-shrinking fabric before it is made into a garment.
In fabrics like denim, it eliminates shrinkage. It makes buying a right-sized pair of jeans a
whole lot easier.
The process
1. The fabric is first moistened, usually by steam. This lubricates the fibres and
primes shrinkability.
2. The fabric is fed in between two hot roll bars on top of a stretchy endless rubber
belt.
3. As the rubber returns to its original length once through the cylinders, the warp
yarns shrink and the weft yarns are packed closer together.
4. After the fabric leaves the rubber belt, it enters a dryer, which locks the fibres in
their shrunken state.
For instance, Sanforized denim shrinks about 2-3% (although it can be more) while
unsanforized denim shrinks as much as 10%.
Wrinkle free finishing
Wrinkle free resin finishing is a process to apply chemical resin onto fabrics
functioning crosslinking between hydrogen bonds in order to enhance
stability.
Cellulosic fiber-containing fabrics are made wrinkle resistant by a durable
press wrinkle-free process
It comprises treating a cellulosic fiber-containing fabric with formaldehyde, a
catalyst capable of catalyzing the crosslinking reaction between the
formaldehyde and cellulose and a silicone elastomer.
Then, heat-curing the treated cellulose fiber-containing fabric, under
conditions at which formaldehyde reacts with cellulose in the presence of the
catalyst without a substantial loss of formaldehyde before the reaction of the
formaldehyde with cellulose.
Non-formaldehyde based resins Non-formaldehyde based resins are made to favour
customers towards the harmful and fatal chemicals.
Dimethyl dihydroxyethylene urea
Polycarboxylic acid Phosphono
phosphinocarboxylic acids
Tentering
Why we tenter fabric?
Straightening the fabric as per the desired dimensions
Drying the fabric
Fabrics after wet finishing, loose their shape due to shrinkage. In tentering, we set fabric
to its final dimensions. It set warp and weft at 90-degree angle by stretching the fabric
from opposite directions and set its dimensions.
Source: Slidehsare.com/tentering process
The whole process is done in a tenter frame, in which chains are fitted with pins and
clips to hold the selvage of the fabric. As the fabric passes through a heated chamber,
creases and wrinkles are removed, the weave is straightened, and the fabric is dried to
its final size.
Crabbing is tenting wool and heat-setting is tentering synthetic materials.
Schreiner finish
In this process fabrics is passed from two rolls under heavy pressure that creates a high
sheen. This is achieved by engraving one of the rolls (steel) with several hundred fine
diagonal lines. The processed fabric reflects light differently. The process is widely used
on cotton & cotton/polyester sateen.
Source; - ScienceDirect.com/Mechanical-finishing-techniques-for-technical- textiles
Durability: - It
Is permanent if the fibre is thermoplastic.
Is durable if the fabric is resin treated but not cured.
Is temporary if the
fibre is non-thermoplastic and not treated with resin.
Flame retardant finish
A fabric is considered flame resistant if it stops burning once the flame source has been
removed. The chemicals that make this happen are called fire retardants(FRs).
There are a number of factors that may play role in flammability of the fabrics. These
can be: -
Fibre type
Yarn structure
Fabric structure
Chemicals applied
What we need to light something on fire?
Three necessary components for a fire are fuel, heat and oxygen(known as fire triangle).
If we can mask/remove one or more of these components, we can improved flame
resistance of fabric.
Where fire resistant fabrics are prominently used?
Flame retardant fabric is an important protective clothing. Firefighters, emergency
personnel require protection from flames. Upholstery, drapery, The military and airline
industries also have multiple needs with regards to fire retardancy.
There are three families of elements that can produce FRs. These families are.
Halogens
Chlorinated (CFRs) and Brominated Flame Retardants (BFRs) Chlorine and bromine are
examples.
Pnictogens
Phosphorus flame retardants (PFRs). These are used to make fire resistant furniture,
mattresses, and thermal insulation materials.
Nitrogen-based flame retardants (NFRs). Commonly, used in nylons, polyolefins,
polyurethane foams, and fire-resistant paints, textiles and wallpapers.
Inorganic flame retardants and mineral compounds
Various organic and inorganic compounds are used along previous mentioned elements
to increase flame retardancy among fabrics.
Working principle
Combustion is an exothermic process that can self-catalyze until oxygen, the fuel or
excess heat is removed. This can be stopped by provide a heat sink on or in the fiber by
use of materials that thermally decomposes through strongly endothermic reactions. If
enough heat can be absorbed by these reactions, the pyrolysis temperature (at which
fibre goes under irreversible reaction to produce char, tars and flammable gasses e.g
CO, H2 etc and non flamble gasses such as CO2, H2O and S and N oxides) of the fiber is
not reached and no combustion takes place.
