Process for manufacturing disposable diapers and diaper briefs, and disposable diapers and diaper briefs obtained by application of this process

A method of manufacturing a disposable diaper having elastic portions and made up of an outer moisture impermeable envelope receiving an absorbent pad thereon, an inner permeable facing and elastic elements fitting in a stretched condition substantially along a curvilinear-shaped-cut-out of said envelope in a central crotch fitting area, and comprising the steps of:

• (a) passing an elongated narrow element, along a longitudinal path of travel, in a stretched condition;
• (b) intermittently depositing liquid adhesive material at high temperature on said elastic element during said passing step (a);
• (c) passing said elastic element, with adhesive material thereon, over a fixed guide means;
• (d) passing said elastic element with adhesive material over a carriage means, arranged down-stream of the fixed guide means in the direction of travel, and being movable intermittently in a transverse direction;
• (e) feeding a flexible sheet around the peripheral surface of a rotary drum such that said sheet remains in contact with said drum for about one-half the rotation of said drum, said drum having a smooth outer surface which is maintained at a substantially constant temperature, said temperature being less than the temperature of said liquid adhesive, the difference between the temperature of the adhesive at the time of contact with said flexible sheet and the temperature of said peripheral surface of the drum being at least 20.degree. C.;
• and
• (f) positioning said movable carriage immediately next to the periphery of said rotary drum at a location such that said carriage means and said drum are not in contact with each other and such that the adhesive coated elastic element contacts said flexible sheet supported by said drum and said sheet together with said elastic element remain in contact with said drum for at least a portion of the rotation of said rotary drum before leaving it, moving said carriage means intermittently in a direction transverse to the direction of rotation of the drum, said temperature difference being sufficient to lead to an immediate adhesive effect capable of withstanding the transverse forces to which said elastic element is subjected owing to the movement of said carriage means whereby said elastic element is laid-down on said drum in an oscillating path, and whereby said elastic element is intermittently attached in a stretched condition along a curved-shaped line to said flexible sheet, with said attaching being effected only due to the temperature difference between the drum and the adhesive material;
• and with the provision that steps (e) and (f) are conducted on a single drum.

A method of continuously attaching an elongated narrow elastic element to a moving flexible sheet material to be employed as an outer moisture impermeable envelope for receiving an absorbent pad of a disposable diaper, said elastic element fitting in a stretched condition substantially along a curvilinear-shaped-cut-out of said envelope to allow a leg therethrough when said envelope is constructed as a diaper, said method comprising the steps of:

• (a) passing an elongated narrow elastic element, along a longitudinal path of travel, in a stretched condition;
• (b) intermittently depositing liquid adhesive material at high temperature on said elastic element;
• (c) passing said elastic element over a fixed guide means;
• (d) passing said elastic element over a carriage means, arranged down-stream of the fixed guide means in the diection of travel, and being movable intermittently in a transverse direction.
• (e) feeding a flexible sheet around the peripheral surface of a rotary drum such that the sheet remains in contact with said drum for about one-half the rotation of said drum, said drum having a smooth outer surface which is maintained at a substantially constant temperature, said temperature being less than the temperature of said liquid adhesive, the difference between the temperature of the adhesive at the time of contact with said flexible sheet and the temperature of said peripheral surface of the drum being at least 20.degree. C.;
• and
• (f) positioning said movable carriage immediately next to the periphery of said rotary drum at a location such that said carriage means and said drum are not in contact with each other and such that the adhesive coated elastic element contacts said flexible sheet supported by said drum, and said sheet together with said elastic element remain in contact with said drum for at least a portion of the rotation of said rotary drum before leaving it, moving said carriage means intermittently in a direction transverse to the direction of rotation of said drum, said temperature difference being sufficient to lead to an immediate adhesion effect capable of withstanding the transverse forces to which said elastic element is subjected owing to the movement of said carriage means whereby said elastic element is laid-down on said drum in an oscillating path, and whereby said elastic element is intermittently attached in a stretched condition along a curved-shaped line by laying said elastic element on said flexible sheet due to the temperature difference between the drum and the adhesive material;
• and with the provision that steps (e) and (f) are conducted on a single drum and said temperature difference is sufficient to lead to an immediate adhesion effect capable of withstanding the transverse forces to which said elastic element is subjected owing to the movement of said carriage means.