PURPOSE
To determine
the resistance of the colour of textiles to the action of artificial human
sweat.
EQUIPMENT
• Chemicals for
the alkaline solution - see preparation of solutions.
• Chemicals for
the acid solution - see preparation of solutions.
• Distilled
water, grade 3
• Scale
• PH-meter
• 2 Measuring
jugs holding at least 1 litre
• Perspirometer
• 11
acrylic-resin or glass plates
• Flat-bottomed
dishes
• Oven,
maintained at (37±2)⁰C
• Light box
with light source D65
• Grey scale
for assessing change in colour (ISO 105-A02)
• Grey scale
for assessing staining (ISO 105-A03)
• Multifibre
adjacent fabric, type DW (ISO 105-F10)
PREPARATION
OF SOLUTIONS
pH regulator
0.1 mol /l Sodium hydroxide solution
(NaOH) - 4.0g NaOH per litre: distilled water.
Alkaline solution, freshly prepared, containing, per
litre:
• 0.5g of
L-histidine monohydrochloride monohydrate (C6H9O2N3∙HCl∙H2O);
• 5g of sodium
chloride (NaCl) and either
• 5g of
disodium hydrogen orthophosphate dodecahydrate (Na2HPO4∙12H2O)
or
• 2.5g disodium
hydrogen orthophosphate dihydrate (Na2HPO4∙2H2O)
The solution is
brought to pH 8 (±0.2) with 0.1 mol/l sodium hydroxide solution (NaOH).
Acid solution, freshly prepared, containing, per litre:
• 0.5g of
L-histidine monohydrochloride monohydrate (C6H9O2N3∙HCl∙H2O)
• 5g of sodium
chloride (NaCl)
• 2.2g of
sodium dihydrogen orthophosphate dihydrate (NaH2PO4∙2H2O)
The solution is
brought to pH 5.5 (±0.2) with 0.1 mol/l sodium hydroxide solution (NaOH).
TEST
SPECIMEN
Two specimens
for each colour and material measuring 4cm x 10cm; one for alkaline and one for
acid.
All products
and parts of products including details such as labels, badges and drawstrings
need to be tested. Both solid and multi-coloured products need to be tested. If
the product is multi coloured, make sure all colours are included in the
specimen to be tested. More specimens could be required if the specimens are
printed, striped or have multiple colours. Different parts in contrast colours
need to be tested, both against each other and against the multifibre adjacent
fabric. Cut specimens of all colours and stitch them together face side to face
side.
If face and
back side are different in colour or construction, both face and back side
needs to be tested. If sample is all over printed and backside is strong
coloured and visible at face side, no need to test back side against multifibre
adjacent fabric. (No need to test light coloured backsides either.)
If details (including prints) are in contrast colour they
need to be tested both against adjacent fabric and the fabric of which the
detail is attached. If not in contrast colour they need to be tested only
against adjacent fabric.
METHOD
Test should be
performed according to ISO 105-E04 or Chinese standard GB/T 3922, below follows
the method in short. The solutions should be freshly prepared i.e. a new
solution should be prepared every day.
1.
Cut specimens measuring 4cm x 10cm.
2.
Attach a specimen to multifibre adjacent fabric of the same size, by sewing
along one of the shorter (4 cm) sides. The multifibre should be next to the
face side.
3.
Switch on the oven and preheat pre-heat perspirometer & acrylic plates for
30 min.
4.
Place the specimens in a dish with 100 ml of the sweat solutions and thoroughly
with the help of glass rod/acrylic plate to wet specimen and multifibre for 30
min.
5.
Pour off the excess solutions from specimen by using wringer /glass.
6.
Place each specimen between two glass or acrylic plates and place them in the
perspirometer. Each perspirometer can hold maximum 10 samples. If less, all 11
plates still have to be placed in the perspirometer. Put a pressure of 12.5 kPa
on the perspirometer using the load, lock it and then remove the load. 12.5 kpa
pressures must be evenly distributed on the sample surface. Plates must be
parallel to each other, inclination of plates due to thick and thin (uneven
sample surface) surface must be avoided.
7. Place the
perspirometer in the oven for 4 hours at (37±2)°C in upright position
8. Take out the
specimens from the oven and perspirometer. Open out each specimen and dry them
in room temperature, not exceeding 60°C, with the specimen only being in
contact at the point of the stitching.
RESULTS
Assess cross staining,
change in colour and colour staining.
