Indirect printing of AGM
The present invention relates to a method of applying absorbent gelling material (AGM) granules by indirect printing onto an carrier layer for use in an absorbent article, particularly diaper for babies or adults, training pants, pull-up diapers (diaper pants), sanitary napkins, panty liners or the like. These articles typically comprise the carrier layer with the AGM particles together with further layers, making up the complete article.
1. A method for indirectly applying absorbent gelling material granules onto a carrier layer for use in an absorbent article, particularly a diaper, which article comprises said carrier layer together with further layers, said method comprises the following steps:
absorbent gelling material granules are taken up by a transfer device from a bulk storage of absorbent gelling material granules,
said transfer device having a surface with recesses, said recesses having an absorbent gelling material surface and an opposed inside, wherein the number, size and position of said recesses determine the amount and pattern of absorbent gelling material granules taken up by said transfer device,
said transfer device being moveable from a loading position adjacent to the bulk storage to a meeting position at which the carrier layer is adjacent to the transfer device
means being provided for retaining said absorbent gelling material granules inside said recesses during movement of said transfer device to said meeting position,
and means being provided for expelling said absorbent gelling material granules onto said carrier layer at said meeting position;
wherein a first glue is applied onto said carrier layer upstream of said meeting position before absorbent gelling material granules are deposited onto said carrier layer from said transfer device in said meeting position and wherein a second glue is applied onto said absorbent gelling material granules after said absorbent gelling materal granules have been deposited onto said carrier layer;
wherein at least one of said first and second glues is a micro-fiber glue.
2. Method as claimed in claim 1 wherein a cover layer carrying glue is applied onto said absorbent gelling material granules downstream said meeting position.
3. Method as claimed in claim 1 wherein said transfer device is a transfer roll, said transfer roll is provided with said recesses on the surface thereof.
4. Method as claimed in claim 1 wherein said carrier layer is transported to and from said meeting position by means of a conveying belt or a rotating support roll.
5. Method as claimed in claim 1 wherein said means for retaining said absorbent gelling material granules in said recesses of said transfer device comprises a vacuum applied to the recesses from said inside of said transfer device.
6. Method as claimed in claim 1 wherein said expelling means for expelling the absorbent gelling material granules from said transfer device onto said carrier layer comprises air jet means.
7. Method as claimed in claim 1 wherein said absorbent gelling material is contained in a hopper having an open bottom passed by said transfer device, whereby said absorbent gelling material granules are filling said recesses of said transfer device by gravity.
8. Method as claimed in claim 1 wherein said absorbent gelling material bulk storage is a container comprising a bed of absorbent gelling material granules and having an open top passed by said transfer device such that said transfer device extends into said bed of absorbent gelling material granules in order for said absorbent gelling material granules to be lifted up into said recesses in said transfer device by applying a vacuum from said inside of said recesses.
9. Method as claimed in claim 1 further using scraping means for holding back absorbent gelling material granules from being moved by said transfer device in excess of the amount required to fill the volume of said recesses.
10. Method as claimed in claim 9 wherein said scraping means is formed by a doctor blade, the distance of which to said transfer means is above 0 mm and up to 1 mm.
11. An apparatus for carrying out the process of claim 1 , said apparatus comprising a transfer device for taking up absorbent gelling material granules from a bulk storage of absorbent gelling material granules, said transfer device having recesses on its surface, the number, the size and position of said recesses determining the amount and pattern of absorbent gelling material granules taken up by said transfer device, said transfer device being moveable from said bulk storage to a position where the carrier layer is passing the transfer device.
12. The apparatus as claimed in claim 11 , wherein said transfer device is a rotating roll.