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NWSP 70.8 Liquid Strike-Through




NWSP 70.8


Wetback After Repeated Strike-Through Time


The NWSP 70.8 Liquid Strike-Through test method is used to examine the ability of diaper coverstock to resist the transport back onto the skin of a liquid which has already penetrated the coverstock.

This test method is intended for Quality Control and is designed for comparison of wetback for different nonwoven coverstocks and treatments. It does not simulate in use conditions for finished products.


A piece of coverstock is placed over a standard absorbent medium (10 plies of filter paper) which is then loaded three times according to the Repeated STT method NWSP 70.7 with a specific quantity of simulated urine. After the third dose a Simulated Baby Weight (SBW) is placed onto the coverstock and absorbent medium to ensure even spreading of the liquid.

A pre-weighed pick-up paper is then placed on the coverstock and the weight (SBW) again put on top.

The mass of liquid absorbed by the pickup paper is defined as wetback.


IPS uses Ahlstrom Grade 989 blotters. IPS conditions and tests at 50% RH and 23°C. IPS tests 10 specimens per sample.


Please note:
SGS-IPS cannot sell or otherwise provide standards, specifications, or test procedures to third parties.