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EP-3812136-B1 - CURVED ELASTIC WITH ENTRAPMENT

EP3812136B1EP 3812136 B1EP3812136 B1EP 3812136B1EP-3812136-B1

Inventors

  • FRITZ, JEFFREY W.

Dates

Publication Date
20260506
Application Date
20200820

Claims (10)

  1. An apparatus for manufacturing an elastic composite structure (102), the apparatus comprising: a first roller (24) configured to transport a web layer (12) in a machine direction (14); a laydown guide (42) configured to guide a laydown pattern of a plurality of elastic threads (18); a rotary anvil (32) comprising a first weld line (62) having a first notch (74) formed in a contact surface (82) of the first weld line (62), the first notch (74) having a first interior (89) configured to receive a portion of a first elastic thread (18) of the plurality of elastic threads (18) and a portion of the web layer (12) therein; wherein the first notch (74) comprises a facing surface (86, 88) defining at least a portion of the first interior (89); characterized in that a smallest orientation angle (98, 100) of a first face axis (92) normal to the facing surface (86, 88) with respect to a contact surface axis (94) normal to the contact surface (82) is a first angle that is less than 90 degrees; wherein the facing surface (86, 88) is a first facing surface (86) defining a first portion of the first interior (89); and wherein the first notch (74) further comprises a second facing surface (88) defining a second portion of the first interior (89); and - wherein the first facing surface (86) is parallel to the second facing surface (88); or - wherein the second facing surface (88) is opposite the first facing surface (86) and the first notch (74) further comprises a bottom surface (84) extending between the first and second facing surfaces (86, 88) and defining a third portion of the first interior (89); or - wherein the first facing surface (86) intersects the second facing surface (88) and the smallest orientation angle (98) of the first face axis (92) is distinct from the smallest orientation angle (100) of the second face axis (92), and both orientation angles (98, 100) are less than 90 degrees with respect to the contact surface (82).
  2. The apparatus of claim 1, further comprising: a second notch (74) formed in the contact surface (82) of the first weld line (62), the second notch (74) having a second interior (89) configured to receive a portion of a second elastic thread (18) of the plurality of elastic threads (18) and a second portion of the web layer (12) therein; wherein the second notch (74) comprises a second facing surface (86, 88) defining at least a portion of the second interior (89); and wherein a smallest orientation angle (98, 100) of a second face axis (92) normal to the second facing surface (86, 88) with respect to the contact surface axis (94) is a second angle that is less than 90 degrees.
  3. The apparatus of claim 2 further comprising a second weld line (62) comprising: a third notch (74) having a third interior (89) formed in a contact surface (82) of the second weld line (62); wherein the third notch (74) comprises a third facing surface (86, 88) defining at least a portion of the third interior (89); wherein a smallest orientation angle (98, 100) of a third face axis (92) normal to the third facing surface (86, 88) with respect to the contact surface axis (94) is a third angle that is less than 90 degrees; and wherein the smallest orientation angle (98, 100) of the third face axis (92) is distinct from the smallest orientation angle (98, 100) of the first face axis (92).
  4. The apparatus of claim 3 further comprising a third weld line (62) comprising a fourth notch (74) having a fourth interior (89) formed in a contact surface (82) of the third weld line (62); and wherein a length of the third weld line (62) in a cross direction orthogonal to the machine direction (14) is shorter than a length of the first and second weld lines (62) in the cross direction.
  5. The apparatus of claim 3, wherein the third notch (74) has a third interior (89) configured to receive a second portion of the first elastic thread (18) and a third portion of the web layer (12) therein.
  6. The apparatus of claim 2, wherein the first weld line (62) further comprises: a third notch (74) formed in the contact surface (82) of the first weld line (62), the third notch (74) having a third interior (89) configured to receive a portion of a third elastic thread (18) of the plurality of elastic threads (18) and a third portion of the web layer (12) therein; wherein the third notch (74) comprises a third facing surface (86, 88) defining at least a portion of the third interior (89); and wherein an orientation angle (98, 100) of a third face axis (92) normal to the third facing surface (86, 88) with respect to the contact surface axis (94) is a third angle.
  7. A method for manufacturing an elastic composite structure (102) comprising: guiding, in a machine direction (14), a first web layer (12) adjacently to a rotary anvil (32) via a first roller (24); guiding an elastic thread (18) adjacently to the rotary anvil (32) via a laydown guide (42); wherein the rotary anvil (32) comprises a weld line (62) having a notch (74) formed in a contact surface (82) of the weld line (62), the notch (74) having an interior (89) configured to receive a portion of the elastic thread (18) and a portion of the first web layer (12) therein; wherein the notch (74) comprises a facing surface (86, 88) defining at least a portion of the interior (89); characterized in that a smallest orientation angle (98, 100) of a first face axis (92) normal to the facing surface (86, 88) with respect to a contact surface axis (94) normal to the contact surface (82) is a first angle that is less than 90 degrees; wherein the facing surface (86, 88) is a first facing surface (86) defining a first portion of the first interior (89); wherein the first notch (74) further comprises a second facing surface (88) defining a second portion of the first interior (89), and - wherein the first facing surface (86) is parallel to the second facing surface (88); or - wherein the second facing surface (88) is opposite the first facing surface (86) and the first notch (74) further comprises a bottom surface (84) extending between the first and second facing surfaces (86, 88) and defining a third portion of the first interior (89); or - wherein the first facing surface (86) intersects the second facing surface (88) and the smallest orientation angle (98) of the first face axis (92) is distinct from the smallest orientation angle (100) of the second face axis (92), and both orientation angles (98, 100) are less than 90 degrees with respect to the contact surface (82).
  8. The method of claim 7 further comprising guiding the elastic thread (18) to create a nonlinear elastic thread pattern.
  9. The method of claim 7 further comprising bonding a second web layer (16) to the first web layer (12) via a horn (34) positioned adjacently to the contact surface (82) of the weld line (62).
  10. The method of claim 7 further comprising controlling the laydown guide (42) to pull the elastic thread (18) toward a corner of the notch (74).

Description

BACKGROUND OF THE INVENTION Absorbent sanitary products, such as disposable diapers, are typically equipped with elastic composite structures that include one or more elastic threads. These elastic composite structures are positioned at various locations throughout the product, including in the waistbands, leg cuff regions, and throughout all or portions of the front or back panels of the product. During the typical manufacturing process of an elastic composite structure, the elastic threads are held in a tensioned state and an adhesive is used to secure the elastic threads between the two facing layers of non-woven materials or webs. The tension in the elastic threads is subsequently released, causing the web material to pucker or fold in the areas that contain the adhered elastic threads. The use of adhesives to bond the elastic threads within elastic composite structures presents a number of disadvantages in both the end product and manufacturing method, including costs associated with the consumable material and undesirable tactile properties of the end product (e.g., stiffness). While thermal or ultrasonic welding techniques have been proposed as alternatives for bonding elastic threads within an elastic composite structure, movement or shifting of the elastic threads between or outside of notches on the anvil during the manufacturing process may result in a given elastic thread breaking or being unanchored over one or more portions of its length. EP3677231 (A1) discloses an apparatus and method for manufacturing an elastic composite structure for an absorbent sanitary product including a bonding unit configured to bond a first web layer to a second web layer via a bond pattern that includes at least one bond line having at least one pair of adjacent bonds. EP3296100 (A1) discloses a composite stretchable member, a wearable article, and a method for producing wearable article. This document teaches providing two sheets which are opposed to each other, and a plurality of elastic elements each disposed between the sheets to extend along a stretchable direction of a composite stretchable member in such a manner as to be stretchable in the stretchable direction. US2019231606 (A1) discloses an apparatus for manufacturing an elastic composite structure for an absorbent sanitary product includes an anvil with weld pattern comprising at least one anchoring region and at least one deactivating region. Accordingly, there is a need for an improved apparatus and method for fabricating an elastic composite structure of an absorbent sanitary product that reduces thread breakage and improves the reliability of bonds that anchor elastic threads in position within an elastic composite structure. BRIEF STATEMENT OF THE INVENTION Embodiments of the invention relate generally to absorbent sanitary products and, more particularly, to an improved apparatus and method for manufacturing an elastic composite structure including curved elastic entrapment for use in an absorbent sanitary product. In accordance with one aspect of the invention, an apparatus for manufacturing an elastic composite structure includes a first roller configured to transport a web layer in a machine direction and a laydown guide configured to guide a laydown pattern of a plurality of elastic threads. A rotary anvil comprises a first weld line having a first notch formed in a contact surface of the first weld line, the first notch having a first interior configured to receive a portion of a first elastic thread of the plurality of elastic threads and a portion of the web layer therein. The first notch comprises a facing surface defining at least a portion of the first interior. A smallest orientation angle of a first face axis normal to the facing surface with respect to a contact surface axis normal to the contact surface is a first angle that is less than 90 degrees. In accordance with another aspect of the invention, a bonding apparatus assembly for manufacturing an elastic composite structure comprises a first rotary anvil comprising a first weld line and comprises a second rotary anvil comprising a second weld line. The first weld line includes a first notch formed in a first contact surface of the first weld line, the first notch having a first interior configured to receive a first elastic thread and a first portion of a web layer therein. The first notch comprises a first facing surface defining a portion of the first interior, and a smallest orientation angle of a first face axis normal to the first facing surface with respect to a first contact surface axis normal to a plane of the first contact surface is a first angle that is less than 90 degrees. The second weld line comprises a second notch formed in a second contact surface of the second weld line, the second notch having a second interior configured to receive a second elastic thread and a second portion of the web layer therein. The second notch comprises a second facing surface definin