Method and apparatus for bonding elastic parts under tension to an advancing carrier
The present disclosure relates to methods and apparatuses for stretching, transferring, and bonding elastic parts under tension to an advancing carrier substrate during the assembly of absorbent articles. A continuous carrier substrate may be advanced in a machine direction at a first speed, and a discrete elastic part may be cut from a continuous elastic substrate having a direction of stretch in a cross direction. The speed of the discrete elastic part is changed from a second speed to the first speed, and the central region of the discrete elastic part is stretched in the cross direction. The discrete elastic part is bonded with the continuous carrier substrate such that the stretched central region extends in the cross direction between the first and second longitudinal edges of the continuous carrier substrate. The discrete elastic part may also be bonded with the carrier substrate with adhesive and/or mechanical bonds.
1 . A method of assembling absorbent articles, the method comprising steps of:
advancing a carrier substrate at a first speed in a machine direction, the carrier substrate comprising a first longitudinal edge and a second longitudinal edge separated from the first longitudinal edge in a cross direction;
advancing a continuous elastic substrate at a second speed in the machine direction, the continuous elastic substrate comprising a first longitudinal edge and a second longitudinal edge separated from the first longitudinal edge in the cross direction, wherein the continuous elastic substrate is stretchable in the cross direction;
cutting an elastic part from the continuous elastic substrate, the elastic part comprising a first end region and a second end region separated from the first end region in the cross direction by a central region;
changing a speed of the elastic part from the second speed to the first speed by rotating a first canted disk and a second canted disk at a variable angular velocity;
stretching the central region of the elastic part in the cross direction;
positioning the elastic part on the carrier substrate such that the stretched central region extends in the cross direction between the first and second longitudinal edges of the carrier substrate; and
bonding the stretched central region of the elastic part with the carrier substrate.
2 . The method of claim 1 , further comprising a step of dividing the elastic part into a first waistband and a second waistband by cutting the carrier substrate along the cross direction through the elastic part.
3 . The method of claim 1 , wherein the step of bonding further comprises applying adhesive to the central region of the elastic part.
4 . The method of claim 3 , wherein the elastic part comprises a leading edge and a trailing edge, and wherein the elastic part defines a first length in the machine direction extending from the leading edge to the trailing edge, and wherein the step of applying adhesive to the central region of the elastic part further comprises applying adhesive along a second length of the elastic part, wherein the second length is less than the first length.
5 . The method of claim 1 , wherein the carrier substrate comprises a topsheet substrate comprising a first surface and an opposing second surface, and wherein the elastic part comprises a first surface and an opposing second surface.
6 . The method of claim 5 , wherein the step of positioning the elastic part on the carrier substrate further comprises positioning the second surface of the elastic part in a facing relationship with the first surface of the topsheet substrate.
7 . The method of claim 6 , further comprising steps of: positioning an absorbent core on the second surface of the topsheet substrate; and bonding a backsheet substrate with the topsheet substrate with the absorbent core sandwiched between the topsheet substrate and the backsheet substrate.
8 . The method of claim 6 , further comprising a step of bonding leg cuffs with the topsheet substrate.
9 . The method of claim 8 , wherein the step of positioning the second surface of the elastic part in a facing relationship with the first surface of the topsheet substrate is performed after the step of bonding leg cuffs with the topsheet substrate.
10 . The method of claim 9 , wherein a portion of the leg cuffs are positioned between the elastic part and the topsheet substrate.
11 . The method of claim 1 , wherein the step of cutting the elastic part from the continuous elastic substrate further comprises advancing the continuous elastic substrate between a rotating knife roll and anvil roll.
12 . The method of claim 11 , wherein the step of changing the speed of the elastic part further comprises accelerating the elastic part on the knife roll or the anvil roll.
13 . The method of claim 1 , wherein the step of stretching the central region of the elastic part in the cross direction further comprises advancing the first end region of the elastic part onto the first canted disk and advancing the second end region of the elastic part onto the second canted disk.
14 . The method of claim 1 , wherein the continuous elastic substrate comprises an elastic film.
15 . The method of claim 14 , wherein the continuous elastic substrate comprises a nonwoven bonded with the elastic film.
16 . The method of claim 1 , further comprising steps of:
cutting a second elastic part from the continuous elastic substrate; and
separating the elastic part and the second elastic part from each other in machine direction by a pitch distance.
17 . The method of claim 1 , further comprising steps of applying adhesive to the elastic part; and rotating the elastic part around an axis of rotation wherein the adhesive is facing radially inward.
18 . A method of assembling absorbent articles, the method comprising steps of:
advancing a continuous elastic substrate in a machine direction, the continuous elastic substrate comprising a first surface and an opposing second surface, the continuous elastic substrate comprising a first longitudinal edge and a second longitudinal edge separated from the first longitudinal edge in a cross direction to define a first width, wherein the continuous elastic substrate is stretchable in the cross direction and comprises corrugations oriented to define corrugation lines extending in the machine direction;
applying adhesive to corrugations on the first surface of the continuous elastic substrate, wherein the adhesive extends in the cross direction for a second width, wherein the second width is less than the first width;
cutting an elastic part from the continuous elastic substrate, the elastic part comprising a first end region and a second end region separated from the first end region in the cross direction by a central region, wherein a zone of adhesive is positioned on the central region and not the first and second end regions;
separating the zone of adhesive into individual stripes of adhesive by stretching the central region of the elastic part in the cross direction; and
adhesively bonding the stretched central region of the elastic part to a carrier substrate with the stripes of adhesive.
19 . The method of claim 18 , further comprising steps of:
advancing the carrier substrate at a first speed;
advancing the continuous elastic substrate at a second speed; and
changing a speed of the elastic part from the second speed to the first speed.
20 . The method of claim 18 , wherein the carrier substrate comprises a topsheet substrate comprising a first surface and an opposing second surface, and wherein the elastic part comprises a first surface and an opposing second surface; and further comprising steps of:
positioning the second surface of the elastic part in a facing relationship with the first surface of the topsheet substrate; and
positioning an absorbent core on the second surface of the topsheet substrate; and bonding a backsheet substrate with the topsheet substrate with the absorbent core sandwiched between the topsheet substrate and the backsheet substrate.