It started in Germany and it is expected to spread in other country depending on the capacity of new diaper manufacturer.

Drylock Technologyes is the new venture of a long-time private label hygiene executive Bart Van Malderen that is getting back into European diaper markets. The biggest distinctive feature of this venture is that diapers they are going to produce will be the first fully fluffless diaper ever (at least for EU market). And they will be the only alternative to DryMax technology from Pampers that introduced a couple of years ago the almost fluffless diaper core. In fact Pampers contains a small amount of fluff (so called curly fibers) in the product altough its main function is to acquire and distribute liquid and not to absorb it.

Core is made of super absorbent polymer encapsulated between 2 layers. The distinctive feature is that SAP is contained in small pockets formed by combination of two layers and are kept in place without (or with a very low amount) additional thermoplastic material but only by means of bonds all over the 2 webs. These bonds are designed to allow controlled and gradual loosening when SAP swallow and expand. This design provide space for SAP volume growth and avoid reduction of SAP performances because of consequent pressure increase after swallowing. More liquid is absorbed and more bonds are broken releasing more space.

The new diaper is made of a new fluffless core consisting of SAP in larger quantity than standard diaper. In order to avoid gel blocking phenomena Drylock uses a very thick acquisition layer (around 150 gsm) that grant some softness to the product. This gives to the product a very thin profile and possibility to claim a great saving in shelf space and transport cost. Additionally it provides great benefit to the user because it fits perfectly as an underwear.

Technology used to produce this core is not so innovative because it is derived by printing process. But it is the first time it is used in diaper manufacturing. It should consists of a drum with a clustering means, an injection nozzle to provide SAP into perforated side of previous means and a system to transport carrier web in a position to properly receive SAP. More info  in the coming days. Stay tuned. 

 

In reality what provides almost the whole product absorbency is SAP. Many producers are trying to introduce a new technology to eliminate completely fluff and obtain a more efficient core from cost point of view.

 Apparatus for transferring particulate material onto a web and build a fluffless absorbent core are not complex from technological point of view. 

Many years ago (and even today on simpler machines) rotary drum to dose SAP and transfer it on an airlaid web was a quite widespread system used in many sanitary napkins production lines. This drum had reservoirs on the surface and  number, size and position of which determining the amount and pattern of SAP granules taken up by the drum and released onto a substrate (generally a nonwoven web).  It was simple and effective, reliable and cheap (the so called indirect printing process).

In diapers the profile of absorbent core, whereby certain regions of the article comprise more SAP than other regions, is the key to get the appropriate core efficiency. And the traditional systems were not able to guarantee proper SAP placements especially at high speed in particular when fine particulate material is used and/ or when small and large quantities of reservoirs are used. 

It has been found that at high speeds, SAP particles are not always satisfactorily dropped (e.g. from a feeder / hopper) into the reservoirs of the drum. Reservoirs may only be partially filled, whilst at certain areas of the drum excess SAP may build up. If vacuum (in the drum) is used to aid filling of the reservoirs, then this SAP build-up may obstruct the vacuum suction and this it may further obstruct the filling of the reservoirs This thus may result in an inaccurate distribution of the SAP in the absorbent cores, or even defects in the formed absorbent cores.

A possible apparatus and method for producing, even at high speed, absorbent structures comprising SAP could have the following structure:

a)a SAP feeder for feeding particles to

b)a drum with multiple reservoirs receiving SAP and transferring it to 

c)a substrate like a nonwoven web

d)with a three dimensional plate applying pressure on part of SAP and guiding it into drum reservoirs

Plate is essential to properly fill reservoirs and guarantee desired SAP profile. Plate type and design can be different and many patents have been filed to protect a specific shape or function.

Vacuum can be used to keep reservoirs filled until the very last moment SAP have to be released and positioned on the substrate.

This product is quite new because absorbent core is made of 2 nonwovens wrapped around a mix of SAP. SAP is kept in position witout use of any fluff but only with a special glue. This system allow to place SAP only where it is needed (and you will see there is no SAP in the back) and of course to save a lot of fluff.

In a size 5 in US you will find about 14g of SAP (and positioning glue). In this way the same absorbency of previous product version is guaranteed.

As we have stated at the beginning it is not completely true it is fluffless because the acqusition layer is still made of fluff. As the previos product there is a patch consisting of a web (usually a resin bonded material) and a layer of curly fibers without any SAP. This is a design very peculiar and it is needed to give to consumers the feeling of a (altough very little) thickness. A completely fluffless core with a very thin product could cause some complaints from the market. Anyhow this design allow to keep the same structure of previous product in contact with the skin of babies. It should reduce possibilities to generate negatives (eg rushes) because hte product is more or less the same.

Here you will find some drawings showing the Pampers Cruiser structure obtained throug a reverse engineering approach.

More detailed info are available.

Development stream to obtain a fluffless core is the positioning of SAP in small spot on 2 different webs. Afterwards these spots are covered with a glue and bonded together. The result is a sandwich of 2 webs with SAP in the middle. Number of spots and their positions can be varied along the core obtaining a very low SAP grammage in the back and high density in the central part where capacity is more needed.

Technology used to produce this core is simple because it consists of engraved rolls to distribute SAP at specific rate but be aware because already many patents were already filed to cover almost completely this subject.

Some market tests are already on going from big manufacturer and we can expect some news in the next months.