PURPOSE
To determine
the resistance of the colour of textiles to saliva according to GB/T 18886.
EQUIPMENT
•
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)
• Chemicals
for the saliva solution (see preparation of solution)
• Distilled
water, grade 3
• Scale
PREPARATION
OF SOLUTION
Saliva
solution, freshly prepared, containing per litre distilled water:
3.0g Lactic
acid (CH3∙CH(OH)∙COOH)
0.2g
Carbamide (H2N∙CO∙NH2)
4.5g Sodium
Chloride (NaCl)
0.3g
Potassium Chloride (KCl)
0.3g Sodium
Sulphate (Na2SO4)
0.4g
Ammonium Chloride (NH4Cl)
No need to
bring the saliva solution to specific pH.
TEST
SPECIMEN
Two
specimens for each colour and material measuring 4 cm x 10 cm.
Details such
as labels, badges and drawstrings also need to be tested. If the product is
multi-coloured, make sure all colours tested. More test specimens could be
required if the product is printed, striped or includes several colours.
If details (including prints) are in contrast colour these need to be
tested both against multifibre adjacent fabric and the fabric of which the
detail is attached. If not in contrast colour, they need to be tested only
against multifibre adjacent fabric.
METHOD
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
adjacent fabric should be next to the face side of the fabric.
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.
NOTE
*To weigh the
specimen and multiply the weight by 50 is an easy way to get correct ratio.
E.g. for a specimen which weight 2g, 100ml solution is needed.
