TECHNOLOGY FIELD

The present invention is directed to a process for manufacturing absorbent articles, and in particular inserts for absorbent article. The present invention is also directed to a continuous laminate for manufacturing the insert according to the present process.

BACKGROUND OF THE INVENTION

Reusable diapers made of cloth have been in use for many years. However, reusable cloth diapers have disadvantages relating to labor costing in handling and the need for effectively laundering and sanitizing soiled diapers for re-use.

The introduction of disposable diapers in recent decades has resolved those problems to some extent. Generally, after use, a soiled disposable diaper may be discarded as it is, without any need of laundering or sanitizing. Additionally, many types of disposable diapers currently available are believed to be superior to cloth diapers at conveying and storing urine away from the skin and/or protecting the skin with skin care compositions, thereby helping to avoid skin conditions such as diaper rash.

For economic reasons, currently most disposable diapers are made of substantial proportions of materials derived from petroleum, such as polypropylene and/or polyethylene. These materials often appear in the form of nonwoven webs, sheets or films.

In recent years concerns have arisen concerning the environment. The manufacture and use of diapers is not an exception, particularly in view of the growing number of babies. One view seems to be that use of disposable diapers is detrimental to the environment because the materials of which they are typically made may be derived from non-renewable resources and require substantial amounts of energy in their manufacture. Additionally, because disposable diapers typically are not re-used or recycled, their use may be deemed by some to be unsatisfactorily taxing upon disposal facilities such as landfills. Two-piece type absorbent articles are known in the art for quite a few years. For example, WO2010/083290, WO2010/083287, WO2010/083260 and WO2010/083293 disclose a two-piece absorbent article comprising an outer cover and an absorbent insert, wherein the insert may have containment and absorption features that prevent soiling of the outer cover by the wearer's exudates, so that the outer cover may be reused after an exudation event and change of inserts, and the insert and/or the outer cover may have features to enhance containment, absorption, economy of materials and/or fit that make them asymmetric about their respective lateral axes, and may have features that direct a user to install the insert and/or the outer cover with correct front- rear orientation relative to the wearer.

In view of the concerns set forth above, it would be advantageous if a wearable absorbent article were available that provides advantages desired by caregivers, while reducing the respective disadvantages. It also would be advantageous if a construction were provided that could simplify manufacturing processes and/or reduce costs.

SUMMARY

The present invention is directed to a process for manufacturing insert absorbent articles, comprising the following steps:

a) providing a continuous first sheet;

b) interlacedly securing absorbent cores in a shape of a triangle or ladder on the first sheet, with gaps spacing the absorbent cores;

c) securing stretched elastic components on the first sheet at the center portion of the gaps to form eiasticized areas, each of the stretched elastic components having a longitudinal direction substantially perpendicular to the machine direction;

d) laminating a second sheet on top of the first sheet, the absorbent cores and the elastic components to provide a laminate; and

e) cutting the laminate along with the gaps to obtain the individual insert absorbent articles with eiasticized areas on both side edges.

In one embodiment, the elastic components are elastic foam, elastic thread, elastic film or a combination thereof.

In one embodiment, the stretch ratio of each of the stretched elastic components to 4.0, preferable 1.75 to 2.5. In one embodiment, the elastic components are cut into pieces from a continuous elastic web before being secured on the first sheet in step c).

Another aspect of the present invention is directed to a continuous laminate comprising:

a first sheet and a second sheet;

interlaced absorbent cores, in a shape of a triangle or ladder, sandwiched between the first and second sheets;

gaps spacing the discrete absorbent cores; and

stretched elastic components positioned at the center portion of the gaps, each of the stretched elastic components having a longitudinal direction substantially perpendicular to the machine direction.

In one embodiment, the laminate further comprises any one or more of the following components: a fastening system, and an absorbent distribution layer positioned between the absorbent core and the second sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates the laminate formed during the present manufacturing process, wherein the sheet facing down is the first sheet and the sheet facing up is the second sheet.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

For the purposes of this description, the following terms have the meanings set forth:

"Insert" means a component of an absorbent article that is adapted to contain and/or absorb urine, feces, menses or any combination thereof, and is adapted to be installable and removable, as a modular unit, from a main piece of the absorbent article.

"Machine direction" is used herein to refer to the direction of material flow through a manufacturing process. In addition, relative placement and movement of material can be described as flowing in the machine direction from upstream in a process to downstream in the process.

"Fastening system" means a system that effects removable fastening, attachment or holding of a first structure to a second structure. The system may have a single fastener component, for example, an adhesive patch on the first structure adapted to adhere to one or more types of surfaces on the second structure, or a hook or patch of hooks on the first structure adapted to catch on one or more types of surfaces on the second structure. Only by way of illustration, any structure such as a pocket, strap, hook, buckle, friction strip etc. on a first structure adapted to capture and retain, in whole or in part, the second structure, is a "fastening system" as used herein. The system also may comprise two or more fastener components, for example, respective components of a hook-and-loop fastening system (such as VELCRO), respective surfaces having a cohesive material applied thereto; male and female snap fastener components, a button and button hole, slot or loop, other fastenably cooperating elements, etc. Other examples of fastening components include zipper components, "zip lock" engaging components, loops, posts, pockets, bands or straps, microfasteners, macrofasteners, and fastening components such as described in WO 1998/029081, WO2002/047597 etc.

"User" means a person who may wear an absorbent article as described herein.

Figure 1 illustrates the plan view of the present insert piece to be used as part of the two-piece absorbent article. The sheet facing down is the first sheet and the sheet facing up is the second sheet.

Referring to Figure 1, the machine direction is indicated. The first sheet flows in the machine direction, i.e. from bottom of the figure to the top of the figure. The first sheet is continuous when provided, so the insert can be produced in a continuous way.

The first sheet can be either the topsheet or backsheet of the insert.

"Backsheet" used herein refers to a sheet that liquids, such as urine, will not pass through, under ordinary use conditions, in a direction generally perpendicular to the plane of the sheet at the point of liquid contact. It can be a single layer of liquid impermeable material, or can be a multi-layered laminate structure in which at least one of the layers is impermeable to liquid. As known in the art, the backsheet can include a liquid permeable outer layer and a liquid impermeable inner layer that are suitably joined together by a laminate adhesive. The adhesive can be applied continuously or intermittently as beads, a spray, parallel swirls, or the like. Suitable adhesives are well known in the art and are commercially available. For example, such alternatives can be obtained from Henkel AG & Co., Germany, or from 3M Corporation, MN, USA. The liquid permeable outer layer can be any suitable material that provides a generally cloth-like texture. One example of such a material is a 20 gsm (grams per square meter) spunbond polypropylene nonwoven web. The outer layer may also be made of the same materials of which the liquid permeable topsheet may be made. Further, it is not a necessity for the outer layer to be liquid permeable, but it is desired that it provides a relatively cloth-like texture to the user. The backsheet is preferably formed by a sheet material having moisture permeability from the viewpoint of preventing stuffiness.

"Topsheet" is used herein to refer to a liquid-permeable nonwoven fabric that is shaped to cover a surface of the insert piece having contact with skin. Natural fiber or synthetic fiber can be used for the nonwoven fabric that makes up the topsheet. Natural fiber includes cotton, cellulose (wood pulp), wool, or silk for example. Synthetic fiber may include, for example, polypropylene (PP), polyethylene (PE), nylon, polyester (PET), or acryl. Synthetic fiber may also include PE PP-mixed nonwoven fabric, PE/PET- mixed nonwoven fabric, or bicomponent fiber (mixed fiber) obtained by appropriately combining the above materials.

Referring to Figure 1, in step b) the discrete absorbent cores are secured on the first sheet. The absorbent cores are in a triangle-shape or ladder-shape, and are interlaced on the first sheet. In other words, the absorbent cores are placed in a line, in which each absorbent core is positioned in a direction traversing the machine direction and arranged in an opposite manner to the adjacent absorbent cores. In this way there is no waste of the first sheet and the second sheet in the present manufacture process. Strip- shaped gaps are therefore formed between the absorbent cores, which are not perpendicular to the machine direction.

The absorbent cores can be secured with an adhesive. The adhesive can be applied continuously or intermittently as beads, a spray, parallel swirls, or the like. Suitable adhesives are well known in the art and commercially available. For example, such adhesives can be obtained from Henkel AG & Co., Germany, or from 3M Corporation, MN, USA. The absorbent core can be secured through respective fixing points in such a design that the shape of the absorbent core is not deformed upon stretching of the outer sheet. In step c), the stretched elastic components are secured on the first sheet, in a direction substantially perpendicular to the machine direction. The stretched elastic components are located at the center portion of the gaps between the adjacent absorbent cores, to form elasticized areas A. The elastic components can also be secured with adhesive. The adhesive used for the elastic components are well known in the art and are commercially available, and can be the same as or different from that used for the absorbent cores.

The terms "elastic" as used herein refer to any material that, upon application of a biasing force, can stretch to an elongated length of at least about 110% of its relaxed, original length (i.e. can stretch to 10% more than its original length), without rupture or breakage, and, upon release of the applied force, recovers at least about 40% of its elongation. For example, a material that has an initial length of 100 mm can extend at least to 110 mm, and upon removal of the force would retract to a length of 106 mm.

Before being secured on the first sheet, the elastic components can be provided as a continuous elastic web and then cut into suitable pieces. Thereafter, the elastic components are stretched at a suitable stretch ratio to provide a force to the insert. The stretch ratio of each of the stretched elastic components is 1.5 to 4.0, preferable 1.75 to 2.5. "Stretch ratio" used herein refers to the ratio of the length of the stretched elastic component to the length of the unstretched elastic component.

The elastic components are well known in the art, and are commercially available. The elastic components can be selected from elastic foam, elastic thread, elastic film and any combination thereof.

In step d) the second sheet is laminated on top of the first sheet, the absorbent cores and the elastic components. Preferably, the second sheet has the same width as the first sheet, so the second sheet can cover the first sheet, the absorbent cores and the elastic components perfectly, without any waste or insufficiency.

The second sheet can be either the topsheet or backsheet of the insert, with a provision that each of the first sheet and the second sheet may not be the topsheet or backsheet at the same time. In other words, when the first sheet is the topsheet, the second sheet is the backsheet, and vice versa. The second sheet might be secured to the first sheet, the absorbent cores and the elastic components with an adhesive. The adhesive can be the same as or different from those used for the absorbent cores and the elastic components. In this way, the laminate of the first sheet, the second sheet, as well as the absorbent cores and the elastic components therebetween, is formed.

In step e), the laminate is cut into individual inserts. The cut is performed along the cutting line 1 in the gaps between the absorbent cores, such that each insert has one integrate absorbent core with elasticized areas A on both side edges.

In one embodiment, the laminate is cut through the elasticized areas A. After cutting through the elasticized areas A, there will be an asymmetric contraction force working in a non-parallel direction to the edge of the absorbent core, referring to Figure 1. Hence, there will be better bending of the absorbent core and the insert. The elastic components extend all the way out to the edge of the topsheet or backsheet margin that will be lifted and will form a barrier at the middle of the product.

Another aspect of the present disclosure is directed to a continuous laminate comprising: a first sheet and a second sheet; interlaced absorbent cores, in a shape of a triangle or ladder, sandwiched between the first and second sheets; gaps spacing the discrete absorbent cores; and stretched elastic components positioned at the center portion of the gaps, each of the stretched elastic components having a longitudinal direction substantially perpendicular to the machine direction.

The first sheet, the second sheet, the absorbent cores, the gaps and the elastic components are as described above.

In a preferable embodiment, the laminate further comprises any one or more of the following components: a fastening system, and an absorbent distribution layer positioned between the absorbent core and the second sheet.

"Fastening system" used herein refers to a system that is able to effect removable fastening, attachment or holding of a first structure to a second structure. The system may have a single fastener component, for example, an adhesive patch on the first structure adapted to adhere to one or more types of surfaces on the second structure, or a hook or patch of hooks on the first structure adapted to catch on one or more types of surfaces on the second structure. By way of illustration, any structure such as a pocket, strap, hook, buckle, friction strip, etc. on a first structure adapted to capture and retain, in whole or in part, the second structure, is a "fastening system" as used herein. The system also may comprise two or more fastener components, for example, respective components of a hook-and-loop fastening system (such as VELCRO), respective surfaces having a cohesive material applied thereto; male and female snap fastener components, a button and button hole, slot or loop, other fastenably cooperating elements, etc. Other examples of fastening components include zipper components, "zip lock" engaging components, loops, posts, pockets, bands or straps, microfasteners, macrofasteners, and fastening components such as described in WO 1998/029081, WO2002/047597 etc.

Acquisition distribution layers are well known in the relevant field. Such is a sub-layer designed to improve fluid-management in hygienic products. An acquisition distribution layer accelerates the acquisition and distribution of fluids to the core layer for increased consumer comfort and discretion. The layer is generally bulky, soft, and three dimensional to promote body fluid distribution over much of the acquisition distribution layer's surface adjacent to the inner sheet (which in turn is adjacent to the skin of the user) before there is substantial absorption of the fluid by the absorbent core located on the other side of the acquisition distribution layer. Otherwise the fluid would overwhelm the absorption material at the relatively narrow point of absorption rather than being spread over a wide area of the absorption core surface for superior absorption. The acquisition distribution layer can be made by a variety of different processes, such as chemical bonding and thermal bonding, which are well known in the art.

The disclosures of all patents, patent applications and any patents which issue therefrom, as well as any corresponding published foreign patent applications, and publications mentioned throughout this patent application are hereby incorporated by reference herein.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention as understandable by one skilled in the art on the basis of the present disclosure.