Process for producing absorbent core structures

A method for producing a sandwich structure comprising a pattern of particulate material, said method comprising the steps of:

• a.) providing an air permeable carrier material and a cover material, wherein each of the carrier and cover material include at least one essentially flat web material;
• b.) providing an essentially endless support means for said carrier material having a support pattern, said support pattern comprising a plurality of support pins on the outer surface of the support means, said support pins having an outwardly extending surface of at least about 0.8 mm2;
• c.) providing a carrier material holding means comprising vacuum air suction;
• d.) positioning said carrier material over said essentially endless support means, whereby said carrier material contacts only said support pattern with its support surface and whereby the relative speed between carrier material and the contact surface of said carrier support means is essentially zero;
• e.) providing a particulate material;
• f.) pre-metering the amount of the particulate material;
• g.) transferring the particulate material to the carrier material and providing a sandwich fixation means;
• h.) combining said cover material with said carrier material and said particulate material being sandwiched there between;
• i.) supporting said carrier material only in the region of the support pattern of the support means;
• j.) deforming said carrier material by said carrier material holding means such that indentations are formed in the unsupported regions of said carrier material;
• and
• k.) transferring said particulate material into said indentations of said carrier material, thereby forming a primary pattern of particulate material.