MXPA01000166A - A method for sealing an absorbent member - Google Patents

Abstract

A web (110) including a fibrous material and superabsorbent material is fed to a knife (120). The web (110) has a first surface, a second surface, a first side edge and a second side edge. The knife (120) cuts the web (110) into individual absorbent members having a pair of opposing cut ends. The individual absorbent members have a first surface, a second surface, a 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. A superabsorbent material movement obstruction agent (122) is applied to the first and second end edges.

Description

A METHOD FOR SEALING A ABSORBENT MEMBER FIELD OF THE INVENTION This invention relates to a method for sealing an absorbent member, and more particularly to a method of sealing an absorbent member that is suitable for use as an absorbent core in a disposable absorbent article.

BACKGROUND OF THE INVENTION Absorbent webs comprising fiber masses, i.e. fibrous webs, are well known in the art. These wefts can imbibe liquids, tsiles as fluids discharged from the body, both by means of an absorption mechanism where the fluid is captured by the fiber material itself and by a capillary absorption mechanism where fluid is acquired by, distributed through and it is stored inside the capillary interstices between the fibers. A means for improving the absorbency characteristics of these fibrous web structures is to incorporate superabsorbent material therein, such as polymeric gelling material (also referred to as hydrogel-forming material, superabsorbent polymers, etc.) which imbibe the fluid. The superabsorbent material serves to retain fluid such as liquids discharged from the body. Such an absorbent structure incorporating particulate hydrogel-forming materials in fibrous webs is disclosed by Weisman and Goldman, U.S. Patent No. 4,610,678, 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 dis, which employ relatively thin absorbent cores and which are, therefore, relatively thin products. Notwithstanding the existence of absorbent cores as described above, there remains the need to provide absorbent cores that reduce and preferably eliminate the phenomenon referred to as gel on the skin. The gel on the skin is the situation where the gelling absorbent materials escfrom the absorbent core and travel through the liner or back sheet on the body side of the absorbent article where they are brought into contact with the wearer's skin. In continuous placing operations of the prior art, the fibers and 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 easily penetrates through the top sheet creating unacceptable amounts of gel on the skin. A solution to the above continuous laying operation was to place another weft such as a tissue or a non-woven web over the top of the continuous web and then cut both the tissue and the continuous web into individual members comprising the core and the web. tissue. The individual members were then placed on the product with the tissue placed between the topsheet and the absorbent core substantially preventing the gelling absorbent material from escaping from the uppermost 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 absorbent core are left open, i.e. the ends of the absorbent core are not covered by the tissue, allowing the absorbent material to esc gelation through the ends of the absorbent core. It is an object of this invention to provide a method for sealing an absorbent core via a continuous positioning operation which avoids the problems of the gel on the skin.

BRIEF DESCRIPTION OF THE INVENTION The invention is a method for sealing an absorbent member. To form the absorbent member, a web comprising a fibrous material and absorbent material is fed to a blade. The plot has a first surface, a second surface, a first lateral edge and a second lateral edge. The blade cuts the weft into individual absorbent members having a first surface, a second surface, a first side edge, a second side edge, a first end edge and a second end edge with the first and second end edges corresponding to the ends cut. An obstructing agent immobilizing the superabsorbent material is applied to the first and second end edges. The motion obstructing agent of the superabsorbent material preferably extends from the first lateral edge towards the second lateral edge, and from the first surface towards the second surface of the individual absorbent members. 25 Absorbent individual members preferably form a core Absorbent in a disposable absorbent article and are placed between the liquid-permeable topsheet and a liquid-impermeable backsheet. As used herein the term "superabsorbent material movement obstructing agent" refers to an external agent applied to a weft comprising the fibrous material and the superabsorbent material, which obstructs the movement of the superabsorbent material through the cut end. Of the plot.

BRIEF DESCRIPTION OF THE DRAWINGS Although the description concludes with the claims that point out in a particular manner and claim 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 placement method for forming absorbent cores of the present invention. Figure 3 is an enlarged cross-sectional illustration of the application of the movement obstruction agent of the superabsorbent material to the individual absorbent members. Figure 4 is a plan view of an individual absorbent member after application of the motion-obstructing agent of the superabsorbent material. ^^. ^ t ^^^^! ^^^^^^^^^^^^^ ?? ^^^^^^^ jj ^^^^^^^^^^^^^^^^^ ^ "^^? | ^^^^^ f ^^ gfc ^^^^^ * j ^^^^^^ 5 ^ j ^^ 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, refer to devices that are placed against or close to the user's body to absorb and contain the various discharged exudates. coming from the body. The term "disposable" is used herein to describe absorbent articles that are not intended to be washed or restored or reused in another way as an absorbent article (ie, they are intended to be discarded after a simple use and , preferably, to be recycled, composted or otherwise disposed of in an environmentally compatible manner). 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 fastener or liners. A preferred embodiment of a unitary absorbent article comprising an absorbent core manufactured by the method of the present invention is the unitary disposable absorbent article., diaper 20, shown in Figure 1. As used herein, the term "diaper" refers to an absorbent article generally worn by infants and adult incontinent persons and worn around the wearer's lower torso. It should be understood, however, 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 diaper 20, generally comprises a liquid-permeable topsheet 22, a liquid-impermeable backsheet 24 bonded to the topsheet 22; and an absorbent core 26 intermediate the topsheet 22 and to the backsheet 24. The diaper 20 preferably further comprises a waist front region 36, a waist rear region 38, a crotch region 37 positioned between the waist front region 36 and the back waist region 38, elasticized folds to leg 28, ear flaps 30, a waist elastic 32 feature and a fastening system 34 one tape tab comprising at least 40. an example of a suitable absorbent article to which may be inserted the absorbent core of the present invention is more fully and fully described in U.S. Patent No. 5,151,092 issued to Buell et al. on September 29, 1992. The absorbent core 26 of the present invention may occur on the apparatus 100, as shown in Figure 2. In a preferred embodiment, the apparatus 100 is integrated into an article manufacturing line disposable absorbent such that the absorbent core 26 of the present invention can be manufactured "in line". (As it used herein, the term "integrated" means interconnected process modules that operate concurrently to produce finished products from raw materials. The term "online" is used to refer to the process of manufacturing the absorbent cores of the invention present on an apparatus that is integrated with the manufacturing line that produces the disposable absorbent articles to which are attached the tape tabs. Examining apparatus 100 in greater detail, a frame 110. the frame 110 comprises fibrous material and equipment is provided superabsorbent The fibrous material may comprise cellulose fibers, in the form of fluff, modified cellulose fibers such as hardened cellulose fibers, synthetic fibers such as ^ ^ G ^^ tl ^^ 'made of cellulose acetate, polyvinyl fluoride, polyvinylidene chloride, acrylics, polyvinyl acetate, polyvinyl alcohol insoluble, polyethylene, polypropylene, polyamides (such as nylon), polyesters, fibers of two components, fibers of 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. Suitable superabsorbent materials include but are not limited to discrete particles of gelling absorbent material and fibrous superabsorbent material such as grafted acrylate fibers and modified superabsorbent fibers. The superabsorbent material may be in any form which can be incorporated into a web or sheet form flexible frame 110. The superabsorbent material, when in contact with fluids such as water or body fluids, absorb such fluids superabsorbent material is typically in the form of discrete particles of gelling absorbent material. The continuous weft 110 is fed to the blade 120 in the direction indicated by the arrows shown in Figure 2. Weft 110 has a first surface or uppermost surface 156, a second surface or lowermost opposing surface 148, a first side edge 140 (not shown in Figure 2), and a second side edge 142 opposite. The blade 120 cuts the weft into individual absorbent members 26 having a pair of opposed cut ends. The absorbent individual members 26 are then fed to the applicator 130 which applies an agent of obstruction of the movement of the superabsorbent material 122 to the individual absorbent members 26.

Of course other webs may be fed with the continuous web 110 towards the blade 120. For example, a nonwoven web or tissue may be placed adjacent the first surface 146 and / or the second surface 148 and the composite material is then fed to the web. blade 120. However, for simplicity, only a single frame 110 is shown in Figure 2. As an alternative to the cutting operation with the blade 120, any process that provides individual absorbent members to the applicator 130 may be used. For example, a training process may be used. discrete of the absorbing member. Referring now to Figures 3 and 4, the individual absorbent members 26 have first and second end edges 163 and 165 corresponding to the cut ends of the weft 110, a first side edge 160, a second side edge 162, a first surface or uppermost surface 246, and a second lower surface or surface 248. The motion obstructing agent of the superabsorbent material 22 is applied only to the ends of the individual absorbent members 26. Preferably, the movement obstruction agent of the Superabsorbent material 122 is applied directly to the end edges 163 and 165. However, the movement obstruction agent of the superabsorbent material 122 can be applied to the The first upper surface or surfaces 246 directly on the end edges 163 and 165 and then allowed to migrate through the member 26 from the first surface 246 to the second surface 248. Alternately, the motion obstruction agent of the Superabsorbent material 122 can be applied to both of the end edges 163 and 165 and to the uppermost surface 246. Preferably, a sufficient amount of superabsorbent material movement obstructing agent 122 is applied to the ends of the members. ? i? r * nr n- - || »- - * - ^ > - > - > ^. ^ JMÍ ^^^. ^ ... ^ .. ^ ,, individual absorbers 26 to completely seal the ends thus preventing the gelling absorbent material from escaping through the ends of the absorbent members 26. By applying the motion obstructing agent of the superabsorbent material 122 to only the end edges 163 and 165, each individual absorbent member 26 has a pair of discrete sealing zones, spaced apart 243 and 245. The zone 243 is located adjacent the first end edge 163 and the region 245 is located adjacent the end edge 165. Preferably, a thin film of motion obstructing agent of the superabsorbent material 122 is applied to the weft such that each zone 243 and 245 is relatively thin. However, the movement obstructing agent of the superabsorbent material 122 can migrate inward from the end edges 163 and 165. Preferably, the migration amount of the motion obstructing agent of the superabsorbent material 122 is minimal such that the zone 243 and 245 each has a width dimension 270 of less than about 10 cm, more preferably, less than about 5 cm, and most preferably less than about 1 cm. As can be seen in Figure 3 the motion obstructing agent of the absorbent material extends along the end edges 163 and 165 through the total absorbent member 26 from the first surface 246 to the second surface 248. The areas 243 and 245 preferably occupy less than 30% of the volume of the absorbent member 26, more preferably less than 20% of the volume of the absorbent member 26, and most preferably less than 10% of the volume of the absorbent member 26.

Suitable agents for the motion obstructing agent of the superabsorbent material include, but are 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 liquid or suitable liquid mixtures. The floating emulsions are preferred and more preferred are the floating emulsions of acrylic or vinyl adhesive polymers. Other suitable agents for the movement obstructing agent of the superabsorbent material also include thermoplastic polymers or polymer compositions having a softening point, as determined by the method ASTM E28"Ring and Ball", within the range of 50 ° C. and 300 ° C. Preferably, this thermoplastic polymer or polymer composition is a wax or a composition containing at least 50% by weight of a wax, this wax or composition preferably having a softening point less than about 180 ° C: More preferably said thermoplastic agent (being a polymer, a wax or a composition derived therefrom) is or contains at least 50% by weight of a copolymer having, at least one of its comonomers, acrylic acid, acrylamide, acrylic esters and / or or derivatives from them. The motion obstructing agent of the superabsorbent material is preferably applied to the total web, but only in discrete discrete zones. Although the motion obstructing agent of the superabsorbent material provides the benefit of obstructing the movement of the superabsorbent material through the cut end of a weft, it may have some negative effects if applied to the entire weft. For example, the agent may increase the rigidity of the frame such that it becomes uncomfortable for the user if the overall screen is applied. The agent can inhibit some of the absorbent properties of the plot and in this way would impact from negative way to the absorbent article which uses a plot that has the agent applied to the total plot. Therefore, in order to achieve the desired effect of obstructing the movement of the superabsorbent material through the cut end of a weft without negatively impacting the operation, comfort or other characteristics of the weft and an absorbent article employing said weft, the motion obstruction agent 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 areas 243 and 245 of the absorbent member 26 are preferably positioned within the waist front region 36 and the waist rear region 38, respectively. Although the zones 243 and 245 may be of such a dimension that they extend into the crotch region 37, this is not preferred. Although the 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 protect in the appended claims all these changes and modifications that are within the scope of this invention.

Claims (10)

1. A method for sealing an absorbent member (26) the method comprising the steps of: a) feeding a web (110) comprising a fibrous material and a superabsorbent material, the web having a first side edge (140) and a second side edge ( 142); b) cutting the web into absorbent individual members (26) having a pair of opposite cut ends; and c) applying a motion obstructing agent of the superabsorbent material (122) to each of the cut ends of the individual absorbent members.

2. The method according to claim 1, wherein the individual members have a first surface (246), a second surface (2 ^ 8), a first side edge (160), a second side edge (162), a first end edge (163) and a second end edge (165), said first and second end edges corresponding to the cut ends, and discrete, spaced sealing zones (243, 245). The method according to claim 1 or 2, wherein the zones extend from the first lateral edge towards the second lateral edge and from the first surface towards the second surface. 4. The method according to any of claim 2 or 3, wherein the areas of the movement obstruction agent of the superabsorbent material have a width of less than about 10 cm. The method according to any of claim 2 or 3, wherein the areas of the motion obstructing agent of the superabsorbent mateirial have a width less than about 5 cm. The method according to any of claim 2 or 3, wherein the areas of the movement obstruction agent of the superabsorbent material have a width of less than about 1 cm. The method according to any of the preceding claims, wherein the movement obstructing agent of the superabsorbent material is a material selected from the group of polymeric solutions or emulsions. The method according to any of claim 1 to 6, wherein the movement obstructing agent of the superabsorbent material is a thermoplastic polymer or a polymer composition having a softening point in the range of 50 ° C to 300 ° C. ° Celsius. The method according to claim 8, wherein the thermoplastic polymer or the polymer composition is a wax or a composition containing at least 50% by weight of a wax. The method according to claim 7, wherein the polymeric solutions or emulsions are either natural or synthetic. & I tweet & ^^^ a