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iResolve - http://iresolve.eu Wed, 15 Jul 2020 07:41:58 +0000 Joomla! - Open Source Content Management en-gb Fluffless Core: technology and process http://iresolve.eu/index.php/component/k2/item/95-fluffless-core-technology-and-process http://iresolve.eu/index.php/component/k2/item/95-fluffless-core-technology-and-process

A new trend in disposable diaper business is to reduce as much as possible fluff amount into the product core. Fluff is only one of core components and not the most absorbent!

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.

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Technology Wed, 29 Aug 2012 16:42:58 +0000
Embossing Process Issues http://iresolve.eu/index.php/component/k2/item/94-embossing-process-issues http://iresolve.eu/index.php/component/k2/item/94-embossing-process-issues

embossing dieRotary embossing systems are tools that have traditionally been used to emboss the webs that form absorbent hygiene products. Typical embossing systems include rotary embossing rolls and cooperating, rotary anvil rolls. Different embossment dies can be fixed to rotary embossing rolls to produce a variety of desired embossment regions for absorbent articles. 

A typical embossed products, such as feminine sanitary napkin comprises a topsheet, absorbent core and backsheet. The latter is usually attached to the topsheet prior to the embossment phase. The attachment of the backsheet to the absorbent core prior to embossment usually limits the depth of the embossment regions, as if the embossment is too deep the backsheet may be damaged during the embossment process, such as by cutting or tearing the backsheet. 

The backsheet is typically made of a water resistant material, such as plastic, which makes the backsheet more vulnerable to damage, than for example a nonwoven web. In addition to harming the appearance of the absorbent article, damage to the backsheet can compromise the effectiveness of the absorbent article. In fact a damaged backsheet could allow absorbed fluids to leave the absorbent article and contact the skin or clothes of a wearer. 

Deep channel embossments in an absorbent article provide improved fit of the absorbent article to the wearer's body, which is important in delivering superior protection performance. Deep channel embossments also provide a pleasant feminine design to the wearer. Further the embossed region also serves as a fluid barrier that prevents fluid from running off to the side of the absorbent article. In addition, the process of forming deep channel embossments can produce embossment regions, not only in the surface contacted by the rotary embossing rolls (typically the body facing surface including the topsheet), but also in the opposing surface (typically the garment facing surface). The garment facing surface of the absorbent core is the surface that will come in contact with the backsheet. The backsheet will often conform to the embossments present in the garment facing surface of the absorbent core, resulting in an uneven surface in the backsheet

The uneven surface of the backsheet causes problems when trying to attach release paper to the surface of the backsheet. Adhesive is usually applied to the release paper first and then the release paper is contacted with the backsheet, such that the adhesive holds the release paper to the backsheet until use. However, as there are valleys present in the backsheet due to the embossments the adhesive present on the release paper will bridge these valleys, and consequently the adhesive will not come into direct contact with the backsheet. The irregular adhesive contact leads to several problems, including poor adhesive transfer from the release paper to the backsheet allowing adhesive to remain on the release paper or reducing its effectiveness of remaining on the absorbent article and transferring to an undesired surface, such as a users panties. 

Another typical issue of rotary embossing process is the difficulty to have even embossing. Embossing depth depends on die pressure. Since what is applied on a die is a force you have to be sure to have a constant surface in contact with absorbent product to produce a constant pressure and carry out an even depth embossing.

Finally 2 recommendations for this process: proper embossing design and its right location along the machine process.

 

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Technology Mon, 27 Aug 2012 22:06:16 +0000
Fameccanica introduces Janus http://iresolve.eu/index.php/component/k2/item/93-fameccanica-introduces-janus http://iresolve.eu/index.php/component/k2/item/93-fameccanica-introduces-janus

Janus DiaperRecently Fameccanica.Data introduced a new machine to produce training pants named Janus. This is a very interesting concept because take its basis from a different product design compared to the ones we can currently find on the market. We can say it is a tentative for Fameccanica to try to became a product innovator and not to simply follow requirements of their clients.

Nowadays training pants (or pull on diapers) are made following 3 typical designs: 

1.- diaper with full-waist elasticization by means of transversal elastic threads and with side sealing. This is a typical design used from many years in Asia and still used from majority of diaper producers. 

2.- diaper with narrow and straight central chassis with elasticated side panels in the front and in the back. This is a concept introduced by P&G and KCC and it is greatly widespread in US and EU. 

3.- Diaper with refastenable closure system on the side panels. Mainly present in US. 

Janus Product

Janus eliminates the need of side seam to connect the front and back portion of the pant-diaper and therefore simplify significantly the whole production process. The innovation consists of new product design with lateral elasticated panels with a mechanical closure system to connect each other. Even though this product configuration is not totally new the method to manufacture such product gives some advantage eliminating a lot of bottle necks in these type of processes. 

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Technology Sun, 26 Aug 2012 13:59:30 +0000