This invention relates to a method of determining the efficiency of an absorbent article having two absorbent layers that have a selected density, basis weight and each layer contains a superabsorbent. More specifically, this invention relates to a method of determining, without bench testing, the efficiency of a disposable absorbent article having two absorbent layers made from a wettable, fibrous material, each layer having a selected density, basis weight and a desired percentage of a superabsorbent.
Many absorbent articles, especially disposable absorbent articles, like diapers, training pants, sanitary napkins, incontinence garments, and the like are constructed with two absorbent layers. Typically, the upper absorbent layer functions as a fluid intake layer and the lower absorbent layer functions as a fluid storage or reservoir layer. Normally, the superabsorbent material is present in the lower absorbent layer. This design allows the fluid which contacts the article to move downward through the upper absorbent and into the lower absorbent layer without being impeded. It is also common practice to construct the upper absorbent layer such that it has a lower density than the lower absorbent layer. This density gradient further facilitates downward fluid movement into the lower absorbent layer.
Now, a method has been invented that can be used to determine the efficiency of an absorbent article having two absorbent layers before the absorbent article is actually manufactured. The absorbent article is constructed from a wettable, fibrous material such as cellulose fluff. The absorbent article has two absorbent layers each having a selected density, basis weight and a desired percentage of a superabsorbent in each of the two layers.
Briefly, this invention relates to a method of determining the efficiency of an absorbent article having first and second absorbent layers each having a selected density, basis weight and a desired percentage of a superabsorbent. The method includes the steps of selecting a density for the first and second absorbent layers. A basis weight of at least 100 grams per square meter (gsm) is then selected for each of the first and second absorbent layers. The percentages of a superabsorbent present in each of the first and second absorbent layers are also selected such that the percentage of a superabsorbent in the first absorbent layer is greater than the percentage of a superabsorbent in the second absorbent layer. The selected densities and percentages of the superabsorbents are then inserted into the following formula:
Vxe2x89xa6[(100xe2x88x92% SAM2)xc3x97(d2xe2x88x92d1)]+[(% SAM1xe2x88x92% SAM2)xc3x97d2]
where: % SAM1 is the percentage of a superabsorbent in the first absorbent layer;
% SAM2 is the percentage of a superabsorbent in the second absorbent layer;
d1 is the density of the first absorbent layer expressed in grams per cubic centimeters;
d2 is the density of the second absorbent layer expressed in grams per cubic centimeters; and
V is the desired value to form an efficient absorbent article.
The selected densities and the selected percentages of a superabsorbent in the first and second absorbent layers are then adjusted to obtain a value xe2x80x9cVxe2x80x9d that is at least equal to 2.
The general object of this invention is to provide a method of determining the efficiency, without bench testing, of an absorbent article having two absorbent layers each having a selected density, basis weight and each containing a desired percentage of a superabsorbent. More specifically, this invention relates to a method of determining the efficiency of a disposable absorbent article having two absorbent layers formed from a wettable, fibrous material, such as cellulose fluff and each absorbent layer having a selected density, basis weight and containing a desired percentage of a superabsorbent.
Another object of this invention is to provide a method of determining the makeup of a dual layer absorbent article using a mathematical formula.
A further object of this invention is to provide a method of determining the percentages of a superabsorbent needed to be inserted into each absorbent layer of a two layer absorbent article.
Still another object of this invention is to provide a method of economically designing a two layer absorbent article.
Still further, an object of this invention is to provide an accurate and inexpensive method of designing a two layer absorbent article wherein each layer has a selected density, basis weight and a desired percentage of a superabsorbent.
Other objects and advantages of the present invention will become more apparent to those skilled in the art in view of the following description and the accompanying drawings.