The absorbency of a diaper can be measured by two major components. The first component is SAP, sodium polyacrylate, which is a super absorbent polymer. Many people hear the word polymer without understanding what a polymer truly is. A polymer is defined as a large molecule that is composed of repeating structural units connected by tight chemical bonds. Polymers are an amazing technology that allow for a diaper to absorb anywhere from 35 to 55 times its own weight in urine (gram per gram put into the diaper core). Polymer looks very much like fine salt crystals. The second component that contributes to the absorbency of a diaper is referred to as wood pulp or cellulose fiber. Wood pulp holds only about 10-13 times its own weight in urine. These two components are the main contributing factors in absorbency of a diaper (gram per gram).

The thickness of a diaper is more easily increased by adding wood pulp to the diaper but you can sacrifice comfort by doing so. Lower end diapers such as typical store brand diapers contain less SAP and more wood-pulp, thus their absorbency and total capacity will be less. While higher end diapers contain a good deal more SAP and wood pulp. High end adult diapers such as the Bambino Diaper, produced by the Bottom Half Group, contains a very high percentage of SAP in their diapers which contributes to it being the most absorbent diaper on the market today. Other high-end adult diaper brands such as the Abena X-Plus appear to be thicker than the Bambino Diaper. But this is due to the fact that Abena uses more fluff pulp (wood pulp), but less SAP. Judging a diaper purely based on thickness would be an inaccurate measure of its true capacity. A side-by-side comparison will show that the Abena X-Plus is a bit thicker but in actuality the Bambino Diaper is more absorbent. This is due to the higher percentage of SAP used by Bambino in all there diapers.

Think of it this way; if the Bambino Diaper and the Abena X-Plus weigh approximately the same, size to size, but the Abena looks a little thicker in appearance. Does this mean that the Abena is more absorbent? No!
Does it mean that the Abena will be dryer? No!
Does it mean that the Abena is more comfortable? No!
Does it mean that after equal voids into both the Abena X-Plus and the Bambino, the Abena will still look thicker? No!
Do you want to be in a thicker Abena X-Plus, (at least before the first void) or in a dryer diaper after the first void like the Bambino?
Do you want a diaper with a reinforced frontal landing zone for multiple refastening, or an Abena which taping system has issues?
Do you want a diaper with a soft foam stretch waist front and back that really does stretch or an Abena with just minimal stretch plastic in the back?
Is thicker really always better, especially when the degree of difference in thickness is so minimal?
These are important points and questions to ask yourself and consider when comparing premium adult diapers as with any product.

Many adult diaper producers will claim their diaper holds more liquid than another diaper, but an important factor to consider is how they run their absorbency tests. Many absorbency tests that are done outside the professional spectrum are done using plain tap water. This essentially voids the true results when it comes to diaper absorbency. Water does not accurately mirror the effects of urine. Water is composed of two hydrogen atoms and one oxygen atom while urine is composed of water and a combination of many organic compounds and ions including sodium and potassium as well as many others.  These additional compounds are extremely important when talking about absorbency.  A more accurate test would be done with a saline solution, which almost completely mirrors the composition of urine.  Again, we return to some of the higher-end diapers as prime examples.  When testing a diaper such as the Abena X-Plus adult diapers with water, it will more than likely hold more with water than being tested with urine. The problem when testing adult diapers with water is that it does not accurately mimic urine’s composition and therefore would show skewed results.  But, when saline solution is substituted instead of water and a test is run, the Bambino Diaper will prove to be more absorbent because of the higher percentage of polymers, (SAP) used.  So, while the fluff pulp may add a tad more thickness to the Abena diaper in its dry unused state it is not reflective of a more absorbent diaper after it is wet.

So, an important point when purchasing diapers to keep in mind is the composition and construction of the core of the diaper that contributes to absorbency.  While Abena and Bambino Diapers are very absorbent and high-end, one must keep in mind that thickness does not always mean more absorbency.  This example can be applied throughout the adult diaper market from lower-end diapers to higher-end diapers.  So, while the more absorbent Bambino Diaper may appear less thick than an Abena X-Plus the composition of the Bambino Diaper, has a higher percentage of polymers, which allows for more absorbency and dryness than its competitors. Just like the myth thicker is better is no longer true. Or the adage (you can’t judge a book by its cover) also applies to (you can’t judge a diaper by its thickness).

1. First and foremost importance is the diaper core (this is where all the action takes place). I won’t at this point get into the more advanced points of core construction yet. But to say the cores of all adult diaper have high percentage of cellulose fiber (wood pulp). This wood pulp comes usually from pine trees and the fibers are usually a ¼ inch or smaller. It gives integrity and absorbance capacity to the diaper.
2. Second is a plastic film, this film is usually made of polyethylene although some films for diapers can also be made of polypropylene or even a blend of both. This film is used as a back sheet that prevents the urine from leaking out of the back of the diaper. In other up coming blogs, we will explore the plastic back seat cont and its function. In greater detail including what is commonly referred to these days as cloth like back sheets.
3. The third component or material is also important because it’s the one your bottom comes directly in contact with when you put the adult diaper on and does also directly affect your skin. This material is referred to as Hydrophilic Non-Woven. It allows the urine to pass through to the diaper core below where the urine is absorbed by the core (fluff pulp) while the surface of the non-woven stays relatively dry because of it’s hydrophilic nature and that non-wovens are made from plastic, most non-woven for disposable diaper are made by a process called Spun Bonding.
4. The fourth important material used in diaper core construction is called Sodium Polyacrylate also known as super absorbent polymers or SAP for short. This material which is similar in look to table salt is what blended into the fluff core to create that gel like material and helps the fluff pulp to hold a greater capacity of urine than it could without it. As a rule of thumb one gram of wood pulp will hold (in free swell state) 10 to 13 times its own weight. But 1 gram of SAP will hold 35 to 55 times its weight in urine (we will get deeper into this subject in other articles on absorbency).
5. The fifth component is tissue. This tissue which is engineered to have a high wet strength is used as a carrier. This carrier helps move the core through the compression and continuous drum forming process.
6. The sixth component is elastic. This elastic is usually made of synthetic rubber or Lycra and is used to help improve the fit. These elastics are also used to form leg cuffs and help enforce standing leg gathers. All used to add to the comfort of the wearer.
7. The seventh component is your frontal tape tabs. Those tape tabs help secure the sides of the diaper to the front of the diaper and use an adhesive material to seal the tabs to the front of the plastic shell (there are many types of tape systems including mechanical type known as Velcro style which uses a hook and loop material instead of a glue type). We will discussing these other types of closure systems later, but your more expensive diapers use a reinforced frontal panel with a very aggressive adhesive tapes which can be taped and re-taped multiple times without tearing. These are most useful on diapers which are designed to hold multiple wettings.
8. The eighth component are standing inner leg cuffs probably the best extra feature to come around and is made of a hydrophobic non-woven which is a non-woven which resists urine from penetrating its surface these inner cuffs are usually made from polypropylene without any added surfactants. These standing inner leg cuffs greatly help in reducing the leaks usually associated with wearing diapers.

There are other components associated with some diapers like wetness indicators, acquisition or distribution layers, stretch tapes, breathable side panels, lotions, and decorated films many of these we will try and cover later.
In other discussions we will examine the pros and cons of the materials and how the choice of these different components will impact on your experience in wearing diapers.