US-12616617-B2 - Apparatus and method of manufacturing an elastic composite structure for an absorbent sanitary product

US12616617B2US 12616617 B2US12616617 B2US 12616617B2US-12616617-B2

Abstract

An apparatus and method for manufacturing an elastic composite structure for an absorbent sanitary product includes at least one structure that guides web layers in a machine direction, an elastic thread combiner that combines a plurality of elastic threads to form a combined elastic thread assembly, and a bonding unit. The bonding unit bonds the web layers together via a bond pattern that includes bond lines that each have at least one pair of adjacent bonds, which anchor the combined elastic thread assembly within a passage defined by a pair of adjacent bonds in each of the plurality of bond lines. The passage is narrower than the combined elastic thread assembly in a non-tensioned state and wider than one of the plurality of elastic threads in a non-tensioned state.

Inventors

Robert Earl Andrews
David Edward Schuette
Jeffrey Wayne Fritz
Justin Marshall Lafferty

Assignees

CURT G. JOA, INC.

Dates

Publication Date: 20260505
Application Date: 20191217

Claims (7)

1 . A method of manufacturing an elastic composite structure comprising: positioning an elastic thread assembly between a first web layer and a second web layer, the elastic thread assembly comprising a plurality of unbonded multifilament elastic threads; bonding the first web layer to the second web layer via a bond pattern comprising a plurality of bond lines having pairs of adjacent bonds; anchoring the elastic thread assembly within a passage formed between the first web layer and the second web layer, the passage defined between facing edges of pairs of adjacent bonds in the plurality of bond lines; feeding the plurality of unbonded multifilament elastic threads under tension in a machine direction toward an ultrasonic bonding assembly; and combining together a subset of the plurality of unbonded multifilament elastic threads upstream of the ultrasonic bonding assembly so that the elastic thread assembly is now combined, wherein the facing edges are spaced apart by a distance that is smaller than an overall diameter of the elastic thread assembly in a non-tensioned state and that is larger than a strand diameter of the plurality of elastic threads in a non-tensioned state.
2 . The method of claim 1 further comprising: positioning a second elastic thread assembly between the first web layer and the second web layer, wherein the second elastic thread assembly comprises a plurality of elastic threads; and anchoring each of the elastic thread assemblies within a respective passage formed between the first web layer and the second web layer; each respective passage defined between facing edges of pairs of adjacent bonds in the plurality of bond lines.
3 . The method of claim 1 further comprising ultrasonically bonding the first web layer to the second web layer to form the bond pattern.
4 . The method of claim 1 further comprising forming the bond pattern using a rotary anvil having a face with a plurality of welding lines defined thereon, each welding line of the plurality of welding lines comprising a plurality of evenly spaced projections.
5 . The method of claim 1 further comprising feeding the elastic thread assembly under tension in a machine direction; and wherein anchoring the elastic thread assembly within the passage comprises anchoring the elastic thread assembly between facing edges of the pairs of adjacent bonds that are oriented non-parallel to the machine direction.
6 . The method of claim 1 further comprising combining together the subset of the plurality of elastic threads within a feeder device of a creel.
7 . The method of claim 1 further comprising combining together the subset of the plurality of elastic threads within a guide roller.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present invention claims priority to U.S. Provisional Patent Application Ser. No. 62/786,609 filed Dec. 31, 2018, the disclosure of which is incorporated herein by reference in its entirety. BACKGROUND 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 for use in an absorbent sanitary product that minimizes or eliminates the use of consumable adhesives such as glue. Absorbent sanitary products, such as disposable diapers, are typically equipped with elastic composite structures that include one or more elastic threads. These elastic composite structure s 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 structure s 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 been proposed as alternatives for bonding elastic threads within an elastic composite structure, the elastic threads are prone to break during the thermal or ultrasonic bonding procedure. When a break occurs upstream of the bonding assembly, the broken elastic thread snaps back toward the feeder or creel and must be manually rethreaded before manufacture can be resumed. Accordingly, there is a need for an improved apparatus and method for fabricating an elastic composite structure of an absorbent sanitary product that minimizes or eliminates machine downtime in the event that an elastic thread breaks during manufacture. It would further be desirable for such an apparatus and method to eliminate or minimize the use of consumable adhesives to secure the elastic threads to the facing web layers. BRIEF DESCRIPTION OF THE INVENTION In accordance with one aspect of the invention, an apparatus for manufacturing an elastic composite structure includes at least one structure configured to guide a first web layer and a second web layer in a machine direction, an elastic thread combiner configured to combine a plurality of elastic threads to form a combined elastic thread assembly, and a bonding unit. The bonding unit is configured to bond the first web layer to the second web layer via a bond pattern comprising a plurality of bond lines each having at least one pair of adjacent bonds and anchor the combined elastic thread assembly within a passage defined by a pair of adjacent bonds in each of the plurality of bond lines. The passage is narrower than the combined elastic thread assembly in a non-tensioned state and wider than one of the plurality of elastic threads in a non-tensioned state. In accordance with another aspect of the invention, a method of manufacturing an elastic composite structure includes positioning an elastic thread assembly between a first web layer and a second web layer, the elastic thread assembly comprising a plurality of elastic threads. The method also includes bonding the first web layer to the second web layer via a bond pattern comprising a plurality of bond lines having pairs of adjacent bonds and anchoring the elastic thread assembly within a passage formed between the first web layer and the second web layer, the passage defined between facing edges of pairs of adjacent bonds in the plurality of bond lines. The facing edges are spaced apart by a distance that is smaller than an overall diameter of the elastic thread assembly in a non-tensioned state and that is larger than a strand diameter of the plurality of elastic threads in a non-tensioned state. In accordance with another aspect of the invention, an elastic composite structure includes a first web layer and a second web layer coupled to the first web layer by a bond pattern comprising a plurality of bond lines, each bond line having at least one pair of adjacent bonds. The elastic composite structure also includes an elastic thread assembly comprising a plurality of elastic threads extending through a passage defined by facing edges of the pairs of adjacent bonds of the bond lines. The facing edges of the pairs of adjacent bonds are spaced apart a by distance that is smaller than an overall diameter of the elastic thread assembly in a non-tensioned state and that is larger t