Measuring and testing – Moisture content or absorption characteristic of material
Reexamination Certificate
1999-12-15
2001-10-09
Williams, Hezron (Department: 2856)
Measuring and testing
Moisture content or absorption characteristic of material
C073S038000
Reexamination Certificate
active
06298714
ABSTRACT:
The invention relates to a device for performing tests on absorbent substrate.
The invention concerns a device for performing tests on absorbent substrates particularly by applying at least one so-called test element to a surface of this substrate.
The invention applies, advantageously though not exclusively, to a device for performing so-called “rewet” tests, on absorbent pads used in the making of hygiene products of the absorbent type, or on the absorbent products themselves.
Hygiene products of the absorbent type means products that comprise at least one pad of absorbent material, for example absorbent in capillary fashion, one surface of which is intended to be at least indirectly applied to a person's body in order to collect a fluid.
In terms of performance, absorbent products such as diapers for babies, products for incontinent persons or feminine hygiene products are evaluated based on two criteria:
capacity to absorb and retain the fluids emitted during use, which may be considered leak prevention,
capacity to isolate the user from the fluids emitted, which can be expressed as moisture prevention.
The constant development of the markets for absorbent products requires manufacturers to continually measure the respective performance of their products based on these two criteria.
While consumer panels can provide relatively precise and reliable information on the rate of leaks, these studies, in order to be statistically valid, must be extensive and are therefore very costly.
But it is mostly because of the response times, which are always very long, that it was necessary to develop laboratory methods that were much faster and more economical.
Access to dummy systems such as the “lab service capability tester” and continuing studies of the correlations obtained between this system and consumer panels have allowed many manufacturers to quickly obtain precise and reliable information on the rate of leaks in their products.
By contrast, the measurement of moisture protection by panels is far more complex and far less reliable.
This is linked, for example, to the variability factors resulting from the individuals and the intrinsic characteristics of their skin.
Moreover, while the “leak” parameter is very pragmatic (leaks either do or do not exist), the same cannot be said for the evaluation of moisture, which is a parameter that is partially subjective (slightly moist, moist, very moist . . . how can this performance be objectively quantified?).
For many years, the evaluation of “moisture prevention” was performed in two different ways, i.e., in vivo and in the laboratory.
In the laboratory, tests were performed based on two measurement concepts:
the so-called “rewet” measurement,
the measurement of surface moisture or contact moisture.
Tests performed in vivo directly involve the properties of the skin of the person wearing the product, but also the normal conditions for use of said products.
The results of tests performed in vivo, which should more accurately reflect the behavior of absorbent products than tests performed in the laboratory, have in fact proven to be subject to problems of interpretation involving a substantial population of the individuals tested.
Researchers attempted to find a solution that would make it possible to perform laboratory tests with a substantial correlation to tests performed in vivo.
Researchers worked to develop an element which, intended to be applied to the absorbent substrate to be tested, had properties comparable to those of people's skin.
Greatly improved test elements using, for example, collagen, were developed and are used today, both for “rewet” measurement and for measuring surface moisture or contact moisture.
As indicated above, the device of the invention relates advantageously, i.e., in a non-limiting way, to rewet measurement.
A rewet test means a test in which:
a sample absorbent pad receives a certain quantity of liquid,
for a predetermined amount of time, the sample is subjected to a pressure, also predetermined, in order to ensure the diffusion and/or the distribution of the liquid,
at least one element of absorbent material, of predetermined weight, is then applied to a surface of the sample and held against this surface for a predetermined amount of time and with a predetermined pressure,
at the end of the application stage, each element of absorbent material is weighed in order to determine the total quantity of liquid collected.
There are many variants of this test, depending for example on the nature of the absorbent elements used, their dimensions and shapes, etc.
The inventor observed that the elements of absorbent material used were generally thin sheets of material, such as elements cut from sheets of filter paper, of collagen, and were applied to the samples to be tested by means of solid bodies.
Nowadays, hygiene products of the absorbent type usually have a structure that is non-uniform.
For example, they can have one of the following criteria:
a fluid-receiving surface that is anatomically conforming, and
a thickness and/or a density that varies depending on the measuring point on the receiving surface.
On articles of this type, rewet tests conducted according to the techniques of the prior art are unreliable, i.e., not only do they give different results on identical articles, but also, they do not reveal the actual rewet indices of the articles tested.
One object of the invention is to obtain a device that, while being economical to produce, allows the effective application of absorbent test elements to absorbent articles whose structure is not uniform.
To this end, the subject of the invention is a device for performing tests on absorbent substrates, particularly by applying at least one of the opposite sides of said substrate to a receiving surface, this device being particularly characterized in that it comprises a means whose function is to ensure the tight application of the substrate to this receiving surface, i.e., a means capable of elastically deforming at least this substrate so that it is pressed tightly against said receiving surface, the tight application means comprising:
a thin wall made of elastically deformable material which, having a size substantially larger than the size of either of the opposite sides of the substrate to be tested, has two opposite sides of its own, including
a so-called frontal side, intended to cooperate at least indirectly with one side of the substrate, and
an opposite, so-called dorsal side, intended to receive actions for applying the frontal side to the substrate,
a means for producing application actions against the dorsal side of the thin wall,
a receiving surface oriented for receiving, at least indirectly, the substrate pressed against it under the action of the thin wall.
REFERENCES:
patent: 4041737 (1977-08-01), Masci
patent: 4332175 (1982-06-01), Krainski, Jr.
patent: 4976138 (1990-12-01), Benninghoff et al.
patent: 5361627 (1994-11-01), Levesque
patent: 5675079 (1997-10-01), Gilman et al.
patent: 5990377 (1999-11-01), Chen et al.
patent: 6085579 (2000-07-01), Herrlein
patent: 0 022 044 A1 (1981-01-01), None
patent: 0 359 501 A2 (1990-03-01), None
patent: 0 692 232 A1 (1996-01-01), None
patent: 0 797 967 A1 (1997-10-01), None
patent: 0 797 968 A1 (1997-10-01), None
patent: 0 813 849 A1 (1997-12-01), None
Kerins John C.
Miles & Stockbridge P.C.
Politzer Jay L.
Williams Hezron
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