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iResolve - http://iresolve.eu Mon, 25 Jan 2021 08:28:39 +0000 Joomla! - Open Source Content Management en-gb Drylock Technologies : a new player in the diaper arena http://iresolve.eu/index.php/component/k2/item/98-drylock-technologies-a-new-player-in-the-diaper-areana http://iresolve.eu/index.php/component/k2/item/98-drylock-technologies-a-new-player-in-the-diaper-areana Drylock Diaper

After many rumors the new diaper from Drylock Technologies has been released. It is currently sold under brand Toujours as private label for supermarket chain Lidl.

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. 


Product Design Mon, 29 Oct 2012 06:20:19 +0000
Requirements for baby diapers http://iresolve.eu/index.php/component/k2/item/96-requirements-for-baby-diapers http://iresolve.eu/index.php/component/k2/item/96-requirements-for-baby-diapers

Primary function of baby diapers  is retaining body fluids, but also a minimizing the negatives associated with wearing such articles by increasing the comfort of the wearer.


Such improvements can mostly be classified to primarily fall within either of two categories: primarily relating to "core technology", i.e. "absorbency" in the broad sense of the word, or primarily relating to "chassis technology", i.e. fit.

The first addresses how to pick up and retain the body waste (generally in some state of fluidity) in an "absorbent (or core) structure", whereby the waste material is acquired by the article (picked up), then conducted away from the location of acquisition (distribution), and then stored (retained).

The second category deals - generally - with the so called "chassis elements" to contain the body waste within the confinement of the article. This can be done by separating the absorbent (core) structure and the outside, e.g. wearers garments or skin, by using an impermeable backsheet. Moreover the chassis should prevent bodily exudates from escaping through the space between the absorbent article and the body of the wearer, which can be achieved by elasticized gatherings at leg and waist openings. Other chassis aspects are enabling application of the article to the wearer - e.g. by providing closure means such as tapes – that are strongly correlated to the “fit”.

Often the terminology "comfort" for the wearer was predominantly addressed by improving chassis elements, such as by adopting the chassis elements of the diaper to provide good "fit" of the article and to be soft and cushioning. It is also well established that reducing the thickness of the article by reducing the primary thickness cause, i.e. the absorbent (core) structure,  helps to improve comfort. This however was always a question of balance between liquid handling performance and thickness. Also a substantial amount of cushioning was considered necessary for comfortable diapers.

The development of absorbent (core) structures of particular thinness has also other beneficial aspects making such a development the subject of substantial commercial interest. For example, thinner diapers are not just less bulky to wear and fit better under clothing they are also more compact in the package, making the diapers easier for the consumer to carry and store. Compactness in packaging also results in reduced distribution costs for the manufacturer and distributor, including less shelf space required in the store per diaper unit.

Designing Product Sat, 01 Sep 2012 07:19:39 +0000
Infinicel - what is made of? http://iresolve.eu/index.php/component/k2/item/92-infinicel-what-is-made-of? http://iresolve.eu/index.php/component/k2/item/92-infinicel-what-is-made-of?

Infinicel Core

Infinicel is the commercial name used in some countries (like US) to advertise core utilized in P&G sanitary napkins. Formula and process to manufacture this core is very secret and not easy to discover. But using some patents we can make a very reliable guess.

Always Infinity core is composed of relatively thin, collapsed, polymeric foam material that, upon contact with aqueous body fluids, expand and absorb such fluids. These collapsed polymeric foam materials are also sufficiently flexible and soft so as to provide a high degree of comfort to the wearer.

These absorbent polymeric foam materials comprise a hydrophilic, flexible, nonionic polymeric foam structure of interconnected open-cells that provides a specific surface area per foam volume. The foam structure has incorporated therein a toxicologically acceptable, hygroscopic, hydrated salt. The chemistry is primarily 2-Ethylhexyl acrylate and divinyl benzene with calcium chloride in the dense layer to maintain collapsed state.

This relatively thin, collapsed polymeric foam materials is obtained by polymerizing a specific type of water-in-oil emulsion, commonly known as High Internal Phase Emulsions or "HIPE". The oil phase of these HIPE emulsions comprises of a monomer component having: (a) a monofunctional glassy monomer; (b) a monofunctional rubbery comonomer; (c) a polyfunctional crosslinking agent component. The oil phase further comprises of emulsifier component that is soluble and will provide a stable emulsion for polymerization. The water or "internal" phase of these HIPE emulsions comprises an aqueous solution containing a water-soluble electrolyte. The weight ratio of the water phase to the oil phase in these HIPE emulsions is not know but should be around 50:1.The polymerized foam is subsequently dewatered to provide the collapsed foam material. 

An important aspect of the process is to carry out the emulsion formation and polymerization steps in a manner such that coalescence of the relatively small water droplets formed in the HIPE emulsion is reduced. This leads to a number average cell size in the resulting polymeric foam material of about 50 microns or less. It is a key mechanism behind consistent formation of this material. This reduction in coalescence can be consistently achieved or by the use of certain emulsifier systems either by the use of lower temperatures during polymerization (curing). Stay tuned for next part.

Product Design Sat, 25 Aug 2012 13:16:10 +0000
How to design an absorbent core http://iresolve.eu/index.php/component/k2/item/87-how-to-design-an-absorbent-core http://iresolve.eu/index.php/component/k2/item/87-how-to-design-an-absorbent-core

A core is generally made of a mix of fluff and SAP (hereunder we wil not cover special cores made of other materials or so called "fluffless core"). Usually this mix is “homogeneously blended” (HB): it means that SAP and fluff are in the same ratio everywhere along the core. The reason to have an HB core is because SAP works better when it is well mixed with fluff and this improves core general  performances. Of course other type of constructions are possible altough, with current  cores available on the market today, they do not reach performances that HB cores can.

Our recommendation is to design an HB core.

Good products have core with a tridimensional shape. It means that a core with uncompressed fluff show a tipical increased thickness (it means more absorbent material) in the crotch area and especially in the front side. See simplified core design on the right. You can see there is a first layer along the whole core and a second one positioned in the center/front area. These two layers can be two distinct cores but generally it is a single core with a 3D profile (usually it is obtained through a profiled mould filled by absorbent material).

You can identify 3 different zones

        * shallow zone:    it is the lightest area mainly teh back of the core

        * deep zone:    it is the heaviest area and it is located where you need more absorbency

        * transition zone:    it is the area between shallow and deep

Typical basis weights vary from 100 to 200 for shallow zone and fro 400 to 700 for deep zone. As you can easily understand depending on what deep zone shape and basis weights you choose for your core you will have a specific distribution of absorbent capacity from front to back. Pic shows a graph of capacity profile for a specific product obtained through a xls software developed by iResolve named PocketShape

Since we choosed to design an HB core it means SAP will follow fluff distribution (if our equipment is able to do it!!). More SAP we add more absorbent capacity you have distributed along the core with same “capacity diagram” that fluff defined.

A simple spreadsheet like PocketShape will help you to obtain the proper “capacity diagram” and modify your core geometry accordingly.

Of corse you can design a more stylish cores, rounded and narrow at crotch area  but the basic rules we have described here above are the same.

Just their application requires more sophisticated tools to predict core performances.

Designing Product Mon, 20 Aug 2012 21:24:06 +0000
Baby Diaper Core : what is made of http://iresolve.eu/index.php/component/k2/item/86-baby-diaper-core-what-is-made-of http://iresolve.eu/index.php/component/k2/item/86-baby-diaper-core-what-is-made-of

absorbent coreUp to 80’s it was general practice to form absorbent core for infant diapers, entirely from wood pulp fluff. Given the relatively low amount of fluid absorbed by wood pulp fluff on a gram of fluid absorbed per gram of wood pulp fluff, it was necessary to employ relatively large quantities of wood pulp fluff, thus necessitating the use of relatively bulky, thick absorbent structures.

During 80’s SAPs were introduced in baby diaper cores and allowed to reduce wood pulp fluff usage. 

These SAPs are superior to fluff in their ability to absorb large volumes of aqueous body fluids, such as urine (i.e., at least about 15 g/g), thus making smaller, thinner absorbent structures feasible. In addition SAP particles typically pack closer than fibrous structures, thus achieving even thinner cores at elevated concentrations.

These SAPs are often made by initially polymerizing unsaturated carboxylic acids or derivatives thereof, such as acrylic acid, alkali metal (e.g., sodium and/or potassium) or ammonium salts of acrylic acid, alkyl acrylates, and the like. These polymers are rendered water-insoluble, yet water-swellable, by slightly cross-linking the carboxyl group-containing polymer chains with conventional di- or poly-functional monomer materials, such as N, N'-methylene-bisacryl-amide, trimethylol-propane-triacrylate or triallyl-amine. These slightly cross-linked absorbent polymers still comprise a multiplicity of anionic (charged) carboxyl groups attached to the polymer backbone. It is these charged carboxyl groups that enable the polymer to absorb body fluids as the result of osmotic forces, thus forming hydrogels.

The degree of cross-linking determines not only the water-insolubility of these SAPs, but is also an important factor in establishing two other characteristics of these polymers: their absorbent capacity and gel strength.

Absorbent capacity or "gel volume" is a measure of the amount of water or body fluid that a given amount of SAPs will absorb. Gel strength relates to the tendency of the SAPs to deform or "flow" under an applied stress. SAPs useful as absorbents in absorbent structures and articles such as disposable diapers need to have adequately high gel volume, as well as adequately high gel strength. Gel volume needs to be sufficiently high to enable the SAP to absorb significant amounts of the aqueous body fluids encountered during use of the absorbent article. Gel strength needs to be such that the SAP formed does not deform and fill to an unacceptable degree the capillary void spaces in the absorbent structure or article, thereby inhibiting the absorbent capacity of the structure/article, as well as the fluid distribution throughout the structure/article.

Prior absorbent structures have generally comprised relatively low amounts (e.g., less than about 50 % by weight) of these SAPs. There are several reasons for this. The SAPs employed in prior absorbent structures have generally not had an absorption rate that would allow them to quickly absorb body fluids, especially in "gush" situations. This has necessitated the inclusion of fibers, typically wood pulp fibers, to serve as temporary reservoirs to hold the discharged fluids until absorbed by the SAP.

More importantly, many of the known SAPs exhibited gel blocking.

"Gel blocking" occurs when particles of the SAP are wetted and the particles swell so as to inhibit fluid transmission to other regions of the absorbent structure. Wetting of these other regions of the absorbent member therefore takes place via a very slow diffusion process. In practical terms, this means acquisition of fluids by the absorbent structure is much slower than the rate at which fluids are discharged, especially in gush situations. Leakage from the absorbent article can take place well before the particles of SAP in the absorbent member are even close to being fully saturated or before the fluid can diffuse or wick past the "blocking" particles into the rest of the absorbent member. Gel blocking can be a particularly acute problem if the particles of SAP do not have adequate gel strength and deform or spread under stress once the particles swell with absorbed fluid.

This gel blocking phenomena has typically necessitated the use of a fibrous matrix in which are dispersed the particles of SAP. This fibrous matrix keeps the particles of SAP separated from one another. This fibrous matrix also provides a capillary structure that allows fluid to reach the SAP located in regions remote from the initial fluid discharge point. However, dispersing the SAP in a fibrous matrix at relatively low concentrations in order to minimize or avoid gel blocking can lower the overall fluid storage capacity of thinner absorbent structures. Usage of lower concentrations of these SAPs limits somewhat the real advantage of these materials, namely their ability to absorb and retain large quantities of body fluids per given volume.

Another reason why extremely high concentrations of SAP were not possible resides in the physical integrity disadvantage of structures made of particulate material. Creating a fibrous matrix therefore also had the advantage of providing a fiber re-enforced structure, similar to those used in many other technical situations where structural re-enforcement is provided by fibrous elements, such as in fiberglass. 

Besides increasing gel strength, other physical and chemical characteristics of these SAPs have been manipulated to improve their performance especially to decrease gel blocking.

Designing Product Mon, 20 Aug 2012 21:18:18 +0000
Fluffless Core for Baby Diapers http://iresolve.eu/index.php/component/k2/item/78-fluffless-core-for-baby-diapers http://iresolve.eu/index.php/component/k2/item/78-fluffless-core-for-baby-diapers

fluffless_coreAll baby diaper manufacturers are looking for new and more efficient core structures. Up to now cores are made of a mix of fibers (generally fluff) and superabsorbent polymer (SAP). The firsts represent the matrix to stabilize the second and keep it more or less fixed into the core.

Moreover fibers have the function to distribute fluid along the core and bring to SAP something to swallow. After last developments and new SAP generations this fluff function has became less and less important.

Therefore a goal for all hygiene absorbent product producers is to eliminate usage of fluff and obtain a core made of SAP only. This would lead to a thinner core and less expensive product.

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.

Product Design Mon, 20 Aug 2012 20:15:04 +0000