Testing |
If you are, or want to be, involved in any facet of the manufacture or sale of baby diapers, sanitary napkins, adult incontinence or similar absorbent products, please read through our pages and contact our Consultant, Philip Hardy, by phone or e-mail.
DCS
Testing Laboratory
Diapers,
Napkins & Underpads
Design and Testing for absorbent products:
The DCS Testing Laboratory is a testing facility for the design and monitoring of absorbent disposable products. We are not allied to any machine or material suppliers and so can provide a totally independent service for manufacturers and buyers.
In order to give a deeper understanding of the products and to aid in innovative design, we have developed new laboratory equipment to add to the standard testing systems prevalent in the industry.
Absorbent
cores: |
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The above
chart relates to baby diapers and gives a clear visualisation
of the fluid in a core related to the ability of the core to retain
it. The blue surface shows the fluid as it is distributed in the
core and the yellow columns show the amount of fluid that each
zone of the diaper can retain under normal "baby" pressures.
The area of the blue surface above the yellow columns is the amount
of fluid that will wet the baby's skin each time the pressure
is applied. |
Please click here to view or download the recent Nonwovens Industry magazine article on diaper absorbency written by DCS Consultant Philip Hardy in May 2009
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| For Buyers & Importers | ||
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New tests - new apparatus
Here
at DCS we have developed an improved set of tests using new and innovative
testing devices. The traditional centrifuge retention test has been replaced
by a variable pressure test that gives results directly related to the
full range of "real life" situations.
These new tests are described below. If you wish to have your baby diapers
tested please contact us at Testing
or ring us at the number shown on our Contacts
page.
Baby and Adult diaper design & testing
Step by step
Step
1 - SAP Indicator analysis
Special combinations of chemicals and indicators are applied
to the diapers to show the mix and spread of SAP when back illuminated.
(Photo in RH column).
High SAP density (green square) and low SAP density (blue square) areas
can be clearly identified.
Photos of these spreads are then combined with zoned retention tests to
quantify the SAP distribution. In this way a 3 dimensional mapping of
the SAP is built up for the diapers. The variation from diaper to diaper
will indicate the level of control of the core formation. Click
to see larger photo
Step
2 - Retention
Full
and zoned retention tests indicate the fluid retention under stepped pressure.
These provide a clear indication of the amount of fluid that will be released
at each pressure equivalent to the baby lying down, sitting or moving.
(DCS use different ranges of pressure for the different diaper sizes directly
related to the baby’s weight range).
This test rig can also be used by diaper manufacturers for the monitoring
of SAP quantities during production. Its advantage over the centrifuge
method being that it applies a range of pressures that are similar to
those encountered in usage and thus can be directly related to customer
feedback. Click
to see retention graph.
Step
3 - Rewet
Rewet tests are carried
out in front, central and back zones, with and without the ADL layer,
to show the intrinsic ability of the absorbent core to prevent fluids
from resurfacing, and the effect that the ADL has on the rewet of the
diaper within the critical load range. Using a zoned rewet combined with
the zoned retentions of Step 2 it is possible to fully map the diffusion
of the fluid through the diaper core and to understand why those rewet
values are being achieved. This better understanding of internal fluid
movement makes the core design a more logical process, rather than one
of trial and error. Click
to see rewet graph
Step 4 - Redistribution
The rewet testing device is also used to check the redistribution
of the fluid caused by repeated loading of the diaper. This mimics the
movements of the baby during use and indicates if the retained fluid within
the core will wet the skin only once or continue to wet the baby each
time that pressure is applied. A well designed diaper will allow the fluid
to redistribute throughout the core when pressure is applied rather than
to repeatedly come to the surface, thus reducing the incidence of diaper
rash. Click
to see redistribution graph
Step 5 - Pad
Integrity
The
diaper is tested using the Hardy Integrity Tester (HIT) apparatus. This
indicates the overall ability of the diaper core to remain unbroken when
subjected to impact. It can also be used to indicate the variation in
strength from diaper to diaper in normal production. A diaper brand is
often judged by the weakest performer in the pack, so this variation in
strength can be a key factor influencing consumer satisfaction.
Click
to see picture of Integrity Tester
Step
6 - Wicking
The diaper is tested for wicking with saline solution. The results of
this test are combined with those of the pad integrity to assist in determining
the optimum density of the core. Increased strength and wicking must be
balanced against the speed of absorption and the soft feel of the diaper.
Other Diaper Testing
Inspection
A full inspection of the diaper and a 3 dimensional analysis
of the "fit". The fit is not just a factor of comfort or visual
aspect, it affects the point of application of the urine thus affecting
the spread and potential leakage of the diaper.
Test Panel
The diapers
are tested on babies of different genders and different relative "shapes"
to give as wide a range of performance as possible
The results are then correlated with the Inspection and Absorption tests
to give a complete picture of the diaper performance. Any anomalies will
be highlighted when the performance in the test panel does not match the
performance predicted by the lab results.
Materials
Material testing can be carried out to determine strengths, tape
adhesion, elastic tension etc, and can assist in resolving any remaining
performance anomalies.
Conclusions
and Design (For manufacturers)
The final conclusions reached will give a clear indication of
the actions that should be taken to improve your diapers to the level
that you require. We can then assist you to achieve these levels by machine
tuning, material changes, machine modification or retrofitting of new
units.
Please contact us if you wish to receive a proposal for testing of your product. E-mail
Disposables Consultancy Service
Copyright © 1999 [DCS]. All rights reserved.
Revised:
March 2010
Click on this image to view larger picture
SAP distribution
Hardy Integrity tester
Retention & Rewet Tester
