Test Methods

Softening

The softening performance is assessed by internal panel tests carried out by experienced persons using terry cotton fabric treated with softener. Two methods are established: APM 91-03 screening test and APM 91-04 pair-wise direct comparison test.

In both cases, the softest fabric sample gets the higher score. Points are given between 0 (worst, usually the untreated reference sample) and 5 (best result). The softness performance ranking is established accordingly. A comparison of results is valid only within the same panel test. Substantive softeners or cationic formulated products are applied by the exhaust method.

Rewetting

The rewetting performance is determined by the capillary rise of water (APM 91-02) on cotton fabric. The treated fabric is cut into stripes and, together with the untreated reference material, marked with a dye and suspended vertically with the lower end immersed into a water bath.The water migrates by capillary force vertically into the fabric stripes and the dye is carried to the height to which the water migrates. The reference stripe is quoted with 100 % rewetting and the rewetting ability of all treated samples is calculated with reference to the blank. The higher the rewetting ability in %, the more hydrophilic the tested softener is.

Non-Yellowing

The non-yellowing performance is determined by APM 96-19 using a LUCI 100 spectrocolorimeter. The cotton fabric is treated with softener. The Berger whiteness index (Wb) is measured on untreated fabric, on treated fabric and on treated/untreated fabric which was exposed to 170 °C for 5 minutes. The lower the difference to the reference, the more resistant the softener is to yellowing caused by heat.