2.3.1 Colour Fastness to washing:
These are accelerated laundering tests designed to evaluate
color fastness to laundering of textiles and textile end products which are
expected to withstand frequent laundering. Stainless
Steel Balls of 0.6mm dia are required to enhance the abradant effect of the laundering
process. To evaluate the color fastness, Change in color and staining of
adjacent fabrics are assessed. To check
Staining on other fibre types multifibre adjacent fabric is being used. It is
made of yarns of various generic kinds of fibres, each of which forms a strip
of specified width providing even thickness of the fabric i.e. Acetate, Cotton,
Nylon, Polyester, Acrylic & Wool. Assessment
of Colourfastness and Staining is being done using grey scales by visually
comparing the difference in colour or contrast between the untreated and
treated specimens with the differences represented by the scale. In Colours
Fastness to dry-cleaning, the method is same as colour fastness to washing,
except that instead of different detergents, dry-cleaning solution
(percholoroethylene or tetrachloroethylene) is used. The Drying condition of
the sample depends upon type of garment and care instruction i.e. Line dry,
Drip dry, flat dry & tumble dry etc.
2.3.2 Colour Fastness to Perspiration:
Human perspiration is acidic/alkaline in nature which
sometimes causes colour change in colored textile materials and staining to
other adjacent textile material. A specimen of colored textile in contact with
other fiber materials (multifibre) is wet out in simulated perspiration
solution, and then subjected to a fixed mechanical pressure and temperature for
defined time. The specimen is then dried and evaluated for colour change &
staining. The testing is performed with Perspirometer at 38 deg C, as human
body temperature is around 38 deg C.
2.3.3 Colour Fastness to light:
It is the resistance to degradation of fabric dyes and prints due to light is an important requirement of a garment because without such resistance,
the garment may change colour and such colour may not be acceptable to a consumer
from an aesthetic point of view. The samples
are placed in special holders and exposed to artificial daylight produced by a special light source which mimics the action of sunlight, but in a more intense
manner so as to speed up the fading effect. A standard (blue wool reference) is
also exposed with the sample and the colourfastness is being assessed by
comparison of the colour change of the exposed portion to the unexposed portion
of the test specimen using scale or blue references used.
2.4 Dimensional Stability after washing:
Consumers consider the dimensional change in a garment to be
a critical performance characteristic. Shrinkage may be ascribed to one or more
of the following four distinct causes such as relaxation, Swelling, Felting,
and Contraction etc. This test method is intended for the determination of
dimensional changes in woven & knit fabrics / garments, when subjected to
repeated automatic laundering procedures commonly used at home. The dimensional
changes of textile specimen subjected to washing are measured using pair of
bench marks applied to the fabric before washing, important bench mark
locations for different garments for assessing the dimensional changes are:
- Shirt - Collar, Collar Band, Body Lengths, Sleeve Lengths,
Width at chest and Cuffs
- Trousers - Front rise, Back rise, Inseams, Outseams, Waist and
Seat
- Pajama Top - Lengths, Sleeves, Hem and Chest
- Pajama Bottom - Inseams, Lengths, Hip and Waist
- Uniform/Dress - Bodice lengths, Skirt lengths, Sleeve lengths,
Shoulders, Chest, Waist, Hip and Hem
- Blouse - Lengths, Sleeve Lengths, Shoulders, Chest and Waist
- Skirt -
Lengths, Hem, Hip and Waist
We also assess the shrinkage after dry-cleaning also and the
test performed in the dry-cleaning plant depend upon the requirement.
