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
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.
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.
The key working part of an absorbent product is its absorbent core,
where the fluid diffuses, is absorbed and is retained. Testing with
variable pressures at increasing levels of saturation reveals the
strengths and weaknesses of the core in handling the fluids. Our
testing results and analyses provide a detailed understanding of
the fluid mechanics within the core and the effectiveness of the
In conjunction with the absorption tests, the core is also tested
for strength to ensure that it will reach its maximum absorption
potential before core failure occurs.
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
We work with our clients to better match the 'required' and the
'actual' profile in terms of retention, so that the raw materials
are used most effectively, thus reducing the material content
to the optimum level (the key to profitable manufacturing).
tests and analysis will show clearly how effectively your materials
are being used and where improvements can be made. (See SAP distribution
and diaper cross section photos in right hand column)
are closely related to real life usage and so can be directly
related to test panel and customer feedback. Once the performance
is understood, it is a simple step to achieving improvements.
With 2 devices
that we have designed, you will be able to carry out your own
design and controls in your Company laboratory. They are the Retention
& Rewet Tester and the Hardy
Integrity Tester. Please contact us for details and quotations.
Buyers & Importers
will carry out tests and provide wetness and leakage results and
graphs. We take the process a step further and reach an understanding
of why the product performs at its particular level of effectiveness.
In this way the costs can be analysed and an understanding of
the 'effectiveness per dollar' paid can be achieved.
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
Baby and Adult diaper design & testing
Step by 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
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
to see retention graph.
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
to see redistribution graph
Step 5 - Pad
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
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.
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 Thediapers
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
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
contact us if you wish to receive a proposal for testing of your product.