MXPA00010927A - An absorbent member and a method for forming the same - Google Patents

Abstract

An absorbent member and a method for forming the absorbent member. A web comprising a fibrous material and superabsorbent material is fed to an applicator. The web has a first side edge and a second side edge. A superabsorbent material movement obstruction agent is applied to the web from the applicator in discrete, spaced apart, continuous zones. The web is then cut through said superabsorbent material movement obstruction agent zones into individual absorbent members having a pair of opposing cut ends.

Description

AN ABSORBENT MEMBER AND A METHOD TO FORM THE SAME FIELD OF THE INVENTION The invention relates to an absorbent member and a method for forming the same, and more particularly to an absorbent member and a method for forming same which is suitable for use as an absorbent core in a desiccant absorbent article.

BACKGROUND OF THE INVENTION Absorbent webs comprising fiber masses, i.e., fibrous web, are well known in the art. These webs can imbibe liquids, such as the fluids discharged from the body, either by an absorption mechanism where the fluid is introduced by the fiber material itself or by a penetration mechanism where the fluid is acquired by, distributed through and stored in the capillary interstices between the fibers A means to improve the absorbency characteristics of these fibrous web structures is to incorporate superabsorbent material in the same material, such as polymeric gelling material (also referred to as hydrogel-forming material, superabsorbent polymers, etc) which imbibes the fluid The superabsorbent material serves to retain fluid such as liquids discharged from the body. Such an absorbent structure incorporating hydrogel-forming materials in the form of particles in fibrous webs is disclosed by Weisman and Goldman, United States Patent No. 610,678, issued September 9, 1986.

The improvement in absorbency provided by the incorporation of gelling absorbent materials has allowed the realization of absorbent articles, such as disposable diapers, which employ relatively thin absorbent cores and which are, therefore, relatively thin products. However the existence of the absorbent cores as described above, there remains a need to provide absorbent cores that reduce and preferably eliminate the phenomenon referred to as a gel on the skin. The gel on the skin is the situation where the absorbent gelling materials escape from the absorbent core and travel through the liner or upper side of the body of the absorbent article where they come into contact with the wearer's skin. In the continuous laying operations of the prior art, the fibers and the superabsorbent materials are mixed together in a continuous web. The continuous web is then cut into individual absorbent members or cores. The individual absorbent members are then placed between a liquid permeable top sheet and a liquid impermeable back sheet to form an absorbent article. Unfortunately, this configuration provides an unsatisfactory product since the gelling absorbent material readily penetrates through the top sheet creating unacceptable amounts of gel on the skin. One solution to the previous continuous laying operation was to place another weft, such as a nonwoven fabric or weft over the top of the continuous weft and then cut both the tissue and the continuous weft into individual members comprising the core and the weft. tissue. The individual members were then placed on the product with the tissue placed between the upper sheet and the absorbent core, substantially preventing the gelling absorbent material from escaping from the upper surface of the absorbent core and thereby reducing the amount of gel on the skin. .

Unfortunately, when for example, the tissue and the continuous web are cut into individual members, the ends of the core are left open, i.e. the ends of the absorbent core are not covered by the tissue, allowing the gelling absorbent material to escape. through the ends of the absorbent core. It is an object of this invention to provide absorbent cores and a method for forming the same by way of a continuous placement operation which avoids the problems of the gel on the skin.

BRIEF DESCRIPTION OF THE INVENTION The invention is an absorbent member and a method for forming the absorbent member. The absorbent member comprises a fibrous material and superabsorbent material. The absorbent member has a perimeter defined by a first side edge, a second side edge, a first end edge and a second end edge The absorbent member has a pair of discrete superabsorbent material motion obstruction agent zones, separate in themselves. , continuous One of the zones is located adjacent to the first end edge and another zone is located adjacent to the second end edge. The absorbent member preferably forms an absorbent core in a disposable absorbent article and is positioned between a liquid permeable topsheet and a liquid impermeable backsheet. To form the absorbent member, a web comprising a fibrous material and superabsorbent material is fed to an applicator. The weft has a first lateral edge and a second lateral edge The agent of obstruction of movement of the superabsorbent material is applied to the web from the applicator in discrete, separate continuous areas. The web is then cut through the areas of the obstructing agent of the movement of the superabsorbent material into individual absorbent members having a pair of opposed cut ends. The individual members have a first surface, a second surface, and a perimeter defined by the first side edge, the second side edge, a first end edge and a second end edge, with the first and second end edges corresponding to the cut ends. The zones preferably extend from the first side edge to the second side edge, and from the first surface to the second surface. As used herein the term "superabsorbent material movement obstructing agent" refers to an external agent applied to a web comprising fibrous material and superabsorbent material, which obstructs the movement of the superabsorbent material through a cut end of the web. plot.

BRIEF DESCRIPTION OF THE DRAWINGS Although the description concludes with the claims pointing out and claiming the present invention differently, it is believed that it will be better understood by the following drawings taken in combination with the accompanying description wherein similar components are given with the same reference number . Figure 1 is a plan view of an absorbent article comprising an absorbent core made in accordance with the method of the present invention.

Figure 2 is a simplified schematic illustration of a continuous laying method for forming absorbent cores of the present invention. Figure 3 is a plan view of a weft after the blocking agent of the movement of the superabsorbent material thereto has been applied thereto and before being cut into individual absorbent members. Figure 4 is a side view of the weft of Figure 3. Figure 5 is a plan view of an individual absorbent member.

Figure 6 is a side view of the individual absorbent member of Figure 5.

DETAILED DESCRIPTION OF THE INVENTION The method of the present invention is particularly suitable for manufacturing absorbent cores for use in disposable absorbent articles. As used herein, the term "absorbent article" refers to devices that absorb and contain exudates from the body, and more specifically, refers to devices that are placed against or close to the wearer's body for absorbent and contain the various exudates discharged from the body. The term "disposable" is used herein to describe absorbent articles that are not intended to be washed or restored or otherwise reused as an absorbent article (ie, they are intended to be discarded after a single use and preferably , to be recycled, composted or otherwise disposed of in an environmentally compatible way). A "unitary" absorbent article refers to absorbent articles that are formed of separate parts joined together to form a coordinated entity such that they do not require separate manipulated parts such as a separate liner and fastener.

A preferred embodiment of a unitary absorbent article comprising an absorbent core manufactured by the method of the present invention is the disposable, unitary absorbent article, diaper 20, shown in Figure 1. As used herein, the term "diaper" refers to to an absorbent article generally worn by infants and adults with incontinence and that worn around the user's lower torso. However, it should be understood that the present invention is also applicable to other absorbent articles such as incontinence briefs, incontinence undergarments, absorbent inserts, diaper liners and liners, feminine hygiene garments, and the like. With reference to Figure 1, an absorbent article, such as a diaper 20, generally comprises a liquid-permeable topsheet 22, a liquid-impermeable backsheet 2 bonded to the topsheet 22, and an absorbent core 26 intermediate to the sheet upper 22 and the back sheet 24. The diaper 20 preferably further comprises a front waist region 36, a rear waist region 38, a crotch region 37 located between the front waist region 36 and the rear waist region 37, folds elastified for the leg 28, ear flaps 30, an elastic waist feature 32 and a fastening system 34 comprising at least one tape tab 40. An example of a suitable absorbent article to which the absorbent core of the invention can be inserted. present is more fully and fully described in U.S. Patent No. 5,151,092 issued to Buell et al. on September 29, 1992. The n The absorbent core 26 of the present invention can be produced in the apparatus 100, as shown in Figure 2. In a preferred embodiment, the apparatus 100 is integrated into a manufacturing line of the disposable absorbent article such that the absorbent core 6 of the invention present can be manufactured "online". (As used here, the term "integrated" means the interconnected process modules that they operate concurrently to produce finished products from raw materials. The term "in line" is used to refer to the process of manufacturing the absorbent cores of the present invention in an apparatus that is integrated with the manufacturing line that produces the disposable absorbent articles to which the tape tabs will be attached.) Examining apparatus 100 in greater detail, a weft 110 is provided. Weft 110 comprises fibrous material and superabsorbent material. The fibrous material may comprise cellulose fibers, in the form of fluff; modified cellulose fibers such as hardened cellulose fibers; synthetic fibers such as those made from cellulose acetate, polyvinyl fluoride, polyvinylidene chloride, acrylics, polyvinyl acetate, non-soluble polyvinyl alcohol, polyethylene, polypropylene, polyamides (such as nylon), polyesters, two-component fibers, three components, mixtures thereof and the like Preferred synthetic fibers have a denier of about 3 denier per filament to about 25 denier per filament, more preferably from about 5 denier per filament to about 15 denier per filament. Also preferably, the surfaces of the fiber are hydrophilic or are treated to be hydrophilic. The superabsorbent materials include but are not limited to discrete particles of gelling absorbent material and superabsorbent fibrous material such as grafted acrylate fibers and modified superabsorbent fibers. The superabsorbent material can be in any form that can be incorporated in a flexible web or sheet to form the web 110. The superabsorbent material, when in contact with fluids such as water or body fluids, absorb these fluids. The superabsorbent material is typically in the form of discrete particles of gelling absorbent material.

The continuous weft 110 is fed to the applicator 120 in the direction indicated by the arrows shown in Figure 2. The weft 110 has a first or upper surface 146 and a second or lower surface 148. The applicator 120 applies a motion obstructing agent. of the superabsorbent material 122 to the first surface 146 of the weft 110 in discrete areas spaced from one edge of the weft 110 to the other edge, that is, across the total width of the frame. The continuous web 110 is then cut by a rotating blade 130 or other cutting device through the areas of the obstructing agent of the movement of the superabsorbent material in the individual absorbent members 26. Of course the webs may be fed with the continuous web 110 towards the applicator 120. For example, a non-woven fabric or weft can be placed adjacent to the first surface 146 and / or the second surface 148 and the composite material is then fed to the applicator 120. However, for simplicity, only a simple weft 110 is shown in Figure 2. Figure 3 shows a plan view of the frame 110 after the blocking agent of the movement of the superabsorbent material 122 has been applied thereto by the applicator 120 and before being cut by the blade 130. Frame 110 has a first side edge 140 and a second side edge 142 opposite. As can be seen in Figure 3, the motion obstructing agent of the superabsorbent material 122 is applied to the weft 110 in discrete, spaced zones 144, which extend continuously or interrupted from the first side edge 140 to the second side edge 142 The zones 144 preferably have a width dimension 170 of from about 0.5 cm to about 20 cm, more preferably from about 1 cm to about 15 cm, and most preferably from about 2 cm to about 10 cm. The width of the zones 144 needs to be wide enough so that a cut can be made in the frame 110 leaving sufficient obstruction agent of the movement of the superabsorbent material on either side of the cut. As shown in Figure 3, the agent 122 is applied to the frame 110 in a rectangular configuration. However, other suitable configurations include but are not limited to, square, oval, dog bone, elliptical, etc. Figure 4 shows a side view of the weft 110 of the weft of Figure 3. As can be seen in Figure 4, the agent for obstructing the movement of the superabsorbent material 122 is applied to the weft 110 in discrete, spaced zones. , which extend through the whole web 110 from the first surface 146 to the second surface 148. Although the agent 122 does not extend through the total thickness of the web 110, i.e., from the first surface 146 to the second surface 148, would provide some obstruction to the movement of the superabsorbent material through the cut end of the weft 110, it is preferred that the agent extend from the first surface 146 to the second surface 148 to provide the maximum possible obstruction. Figure 5 shows a plan view of an individual absorbent member 26 which has been cut from the weft 110 by the blade 130. The absorbent member 26 has a perimeter 158 defined by a first side edge 160, a second side edge 162, a first end edge 163 and a second end edge 165. The first and second end edges 163 and 165 corresponding to the cut ends of the absorbent member 26. The absorbent member 26 has a pair of discrete, spaced apart areas 243 and 245, which extend continuously or interrupted from the first side edge 160 to the second side edge 162. The area 243 is located adjacent the first end edge 163 and the area 245 is located adjacent the end edge 165. The areas 243 and 245 are the cut portions of the zones 144 in the continuous frame 110. The zones 243 and 245 preferably have a dimension of width 270 from about 0.25 cm to about 10 cm, more preferably from about 0.5 cm to about 7.5 cm, and most preferably from about 1 cm to about 5 cm. When viewed from above as in Figure 5, the areas 243 and 245 preferably occupy less than 30% of the absorbent member 26, more preferably less than 20% and most preferably less than 10%. The percentage is calculated simply by adding the two dimensions 270 together then dividing the sum by the total length dimension 272 of the absorbent member 26 and then multiplying the result by 100. The dimension 275 of the absorbent member 26 typically referred to as the width of the member, not needs to be included in this calculation since the dimension 275 is the same for both the member 26 and the zones 243 and 245. Figure 6 shows a side view of the individual absorbent member 26 of Figure 5. As can be seen in Figure 6, the agent obstructing the movement of the superabsorbent material 122 is applied to the absorbent member 26 in discrete, spaced zones 243 and 245, which extend through the entire absorbent member 26 from the first surface 246 to the second surface 248 Agents suitable for the agent obstructing the movement of the material superabsorbent, but not limited, to polymeric solutions or emulsions, both natural (for example, natural rubber latex) and synthetic, in which the liquid is water or any other suitable liquid or mixture of liquids. Running water emulsions are preferred and more preferred are running water emulsions of vinyl and acrylic adhesive polymers. The blocking agent of the movement of the superabsorbent material is preferably not applied to the total web, but only in discrete, separate zones. Although the blocking agent of the movement of the superabsorbent material provides the benefit of obstructing the movement of the superabsorbent material through the end cut, this can have some negative effect if it is applied to the whole of the frame. For example, the agent may increase the rigidity of the frame such that it becomes uncomfortable for the user if it is applied to the overall frame. The agent can inhibit some of the properties of the weft and thus negatively impact the absorbent article, which employs a weft having the agent applied to the total weft. Therefore, in order to achieve the desired effect of obstructing the movement of the superabsorbent material through the cut end of the weft without negatively impacting the operation, comfort or other properties and characteristics of the weft and the absorbent article employing said , weft, the obstructing agent of the movement of the superabsorbent material is applied to the weft in only discrete, separate zones. When incorporated into an absorbent article, such as the diaper 20 shown in Figure 1, the zones 243 and 245 of the absorbent member 26 are preferably positioned within the front waist region 36 and the rear waist region 38, respectively. Although, the zones 243 and 245 may be of such dimensions that they extend toward the crotch region 37, this is not preferred.

Although particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, attempts are made to protect all these changes and modifications within the scope of this invention in the appended claims.

Claims (11)

1. An absorbent member comprising a fibrous material and superabsorbents, said absorbent member having a perimeter defined by a first side edge, a second side edge, a first end edge and a second end edge, said absorbent member characterized in that said absorbent member having a pair of discrete, discrete, self-moving, continuous obstruction material motion obstructing agent areas, one of said zones being located adjacent the first end edge and another zone being located adjacent the second end edge.

The absorbent member according to claim 1, wherein said areas of the movement obstructing agent of the superabsorbent material have a width of about 0.5 cm to about 5 cm.

The absorbent member according to claim 1, wherein said areas of the movement obstructing agent of the superabsorbent material have a width of about 1 cm to about 2.5 cm.

The absorbent member according to any of claims 1 to 3, wherein the movement obstructing agent of the superabsorbent material comprises a material selected from the group of polymer solutions or emulsions.

The absorbent member according to any of claims 1 to 4, wherein the absorbent member forms an absorbent core in a disposable absorbent article.

The absorbent member according to claim 5, wherein the absorbent core is placed between a liquid permeable top sheet and a liquid impermeable back sheet.

7. A method for forming an absorbent member, said method comprising the steps of: a) feeding a web comprising a fibrous material and superabsorbent material, said web having a first side edge and a second side edge; b) applying a blocking agent for the movement of the superabsorbent material to said frame in continuous, discrete, separate zones; and c) cutting the web through the areas of the motion obstructing agent of the superabsorbent material into individual absorbent members having a pair of opposite cut ends.

The method according to claim 7, wherein the individual members have a first surface, a second surface, and a perimeter defined by a first side edge, a second side edge, a first end edge and a second end edge, said first and second end edges corresponding to said cut ends.

The method according to claim 7 or 8, wherein the zones extend from the first lateral edge to the second lateral edge and from the first surface to the second surface.

The method according to claim 7 or 8, wherein said continuous, discrete, separate, continuous areas of the obstruction of movement of the superabsorbent material have a width of about 1 cm to about 10 cm.

11. The method according to any of claims 7 to 9, wherein said discrete, separate, continuous areas of the obstruction of movement of the superabsorbent material have a width of about 2 cm to about 5 cm. The method according to any of claims 7 to 11, wherein the motion obstructing agent of the superabsorbent material comprises a material selected from the group of polymeric solutions or emulsions. The method according to claim 12, wherein the polimépcas solutions or emulsions are, either natural or synthetic