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WO1999045873A1 - Article absorbant a rabats comportant un film microporeux extensible - Google Patents

Article absorbant a rabats comportant un film microporeux extensible Download PDF

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Publication number
WO1999045873A1
WO1999045873A1 PCT/US1998/004651 US9804651W WO9945873A1 WO 1999045873 A1 WO1999045873 A1 WO 1999045873A1 US 9804651 W US9804651 W US 9804651W WO 9945873 A1 WO9945873 A1 WO 9945873A1
Authority
WO
WIPO (PCT)
Prior art keywords
microporous film
extensibility
flaps
absorbent article
backsheet
Prior art date
Application number
PCT/US1998/004651
Other languages
English (en)
Inventor
Kazushige Kishida
Original Assignee
The Procter & Gamble Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by The Procter & Gamble Company filed Critical The Procter & Gamble Company
Priority to PCT/US1998/004651 priority Critical patent/WO1999045873A1/fr
Priority to AU65477/98A priority patent/AU6547798A/en
Priority to PCT/US1998/023029 priority patent/WO1999045871A1/fr
Priority to AT98955201T priority patent/ATE235206T1/de
Priority to DE69812718T priority patent/DE69812718T2/de
Priority to US09/623,814 priority patent/US6328723B1/en
Priority to CA002322455A priority patent/CA2322455C/fr
Priority to EP98955201A priority patent/EP1061879B1/fr
Priority to JP2000535287A priority patent/JP4509379B2/ja
Priority to KR10-2000-7009978A priority patent/KR100489858B1/ko
Priority to ES98955201T priority patent/ES2191975T3/es
Priority to AU12063/99A priority patent/AU1206399A/en
Priority to CNB988138395A priority patent/CN1243523C/zh
Priority to BR9815687-0A priority patent/BR9815687A/pt
Publication of WO1999045873A1 publication Critical patent/WO1999045873A1/fr

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F13/00—Bandages or dressings; Absorbent pads
    • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/51—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the outer layers of the pads
    • A61F13/514—Backsheet, i.e. the impermeable cover or layer furthest from the skin
    • A61F13/51456—Backsheet, i.e. the impermeable cover or layer furthest from the skin characterised by its properties
    • A61F13/51464—Backsheet, i.e. the impermeable cover or layer furthest from the skin characterised by its properties being stretchable or elastomeric
    • A61F13/51466—Backsheet, i.e. the impermeable cover or layer furthest from the skin characterised by its properties being stretchable or elastomeric providing stretchability without the use of elastic material
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F13/00—Bandages or dressings; Absorbent pads
    • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/45—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the shape
    • A61F13/47—Sanitary towels, incontinence pads or napkins
    • A61F13/476—Sanitary towels, incontinence pads or napkins characterised by encircling the crotch region of the undergarment, e.g. with flaps
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F13/00—Bandages or dressings; Absorbent pads
    • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/51—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the outer layers of the pads
    • A61F13/514—Backsheet, i.e. the impermeable cover or layer furthest from the skin
    • A61F13/51456—Backsheet, i.e. the impermeable cover or layer furthest from the skin characterised by its properties
    • A61F13/51458—Backsheet, i.e. the impermeable cover or layer furthest from the skin characterised by its properties being air-pervious or breathable
    • A61F13/5146—Backsheet, i.e. the impermeable cover or layer furthest from the skin characterised by its properties being air-pervious or breathable having apertures of perforations

Definitions

  • the present invention relates to an absorbent article with flaps comprising a microporous film having extensibility. More concretely, the present invention relates to an absorbent article with flaps which comprise a microporous film having extensibility.
  • a microporous film having breathability is well known and used for various consumer products such as packaging film and absorbent articles.
  • There are prior art which are directed to improvement of such a microporous film such as U.S. Patent 4,923,650 published on May 8, 1990, JP Patent publication 93/230252-A published on September 7, 1993, JP Patent publication 96/225680- A published on September 3, 1996, JP Patent publication 94/62794-B published on August 17, 1994, JP Patent publication 95/231913-A published on September 5, 1995, JP Patent publication 96/300436-A published on November 19, 1996, JP Patent publication 96/300498-A published on November 19, 1996, JP Patent publication 96/300499-A published on November 19, 1996, JP Patent publication 96/300500-A published on November 19, 1996, and JP Patent publication 87/167332-A published on July 23, 1987.
  • microporous film described in the prior art worked quite well as a backsheet of an absorbent article which requires breathability and liquid impermeability.
  • prior art which are directed to a process for making a microporous film and the microporous film made by the process, such as U.S. Patent 4,116,892 published on September 26, 1978, U.S. Patent 4,153,751 published on May 8, 1979, and U.S. Patent 4,289,831 published on September 15, 1981.
  • U.S. Patent 4,116,892 published on September 26, 1978
  • U.S. Patent 4,153,751 published on May 8, 1979
  • U.S. Patent 4,289,831 published on September 15, 1981.
  • Absorbent articles such as a sanitary napkin having a portion of extensibility are disclosed in prior art, such as PCT publication WO 97/12576 published on April 10, 1997, PCT publication WO 96/12462 published on May 1 , 1996, U.S. Patent 5,389.094 published on February 14, 1995 and U.S. Patent 5,704,930 published on January 6, 1998.
  • the flaps of the sanitary napkin are provided extensibility for relieving the stresses that develop in the flaps when the flaps are folded down and under a wearer's undergarment.
  • the extensibility can be provided by a number of different processes.
  • the extensibility on the flaps can be provided by mechanically straining, corrugating, "ring-rolling", heating and deforming, subjecting portions of the flaps to compression between mating plates, and the like.
  • These processes include the process of applying a strain to a material to mechanically and permanently deform the material. Extensibility on the material is provided by remaining permanent deformation on the material. Therefore, a degree of extensibility is determined by a degree of an applied strain. The more extensibility requires, the higher strain is applied to the material.
  • microporous films are commonly used for a breathable backsheet of an absorbent article.
  • Microporous films typically comprise a blend of a thermoplastic polymer and an inorganic filler such as calcium carbonate. The blend undergoes pore formation upon stretching as the inorganic filler separates from the polymer due to stress concentration. The formation of micropores permits the film to be breathable allowing the passage of vapor through the micropores while retarding the passage of liquid. While microporous films have good breathability, microporous films have lower "strain at break" than an ordinary non-microporous film.
  • the present invention relates to an absorbent article having flaps.
  • the absorbent article comprises a topsheet, a backsheet and an absorbent core therebetween.
  • the backsheet comprises a breathable microporous film.
  • the breathable microporous film is made by stretching a mixture of a thermoplastic resin and inorganic fillers at least in one direction.
  • the flaps comprise a composite sheet including a flap topsheet and an extension of the breathable microporous film.
  • the flaps are imparted a predetermined extensibility thereon.
  • the backsheet has breathability on substantially entire area of the backsheet.
  • the breathable microporous film has a basis weight of 30 g/m 2 or above. At least a part of the composite sheet is imparted the predetermined extensibility by straining at least a part of the breathable microporous film.
  • the predetermined extensibility is from about 50 % to about 100 %.
  • FIG. 1 is a top plan view of a preferred sanitary napkin embodiment of the present invention.
  • FIG. 2 is a lateral cross-sectional view taken along line 2-2 of Figure 1 through the corner region of the flaps of the sanitary napkin.
  • FIG. 3 is a fragmentary enlarged cross-sectional view of a part of the absorbent core and a part of the backsheet of the sanitary napkin.
  • FIG. 4 is a side elevational view of the ring rolling unit used for making the sanitary napkin.
  • FIG. 5 is a front elevational view of the ring rolling unit used for making the sanitary napkin.
  • FIG. 6 is a fragmentary enlarged cross sectional view of the tooth engagement of the ring rolling unit shown in FIG. 5.
  • FIG. 7 is a graph showing a relationship between strain distribution for the applied strain (AS) to obtain a predetermined extensibility and strain distribution for the material strain at break (MS).
  • AS applied strain
  • MS material strain at break
  • FIG. 1 A preferred embodiment of a sanitary napkin 20 of the present invention is shown in FIG. 1.
  • the sanitary napkin 20 basically comprises an absorbent means (or "main body portion") 22, and two flaps 24.
  • the sanitary napkin 20 has two surfaces, a body-contacting surface or "body surface” 20A and a garment surface 20B.
  • the sanitary napkin 20 is shown in FIG. 1 as viewed from its body surface 20A.
  • the body surface 20A is intended to be worn adjacent to the wearer's body.
  • the garment surface 20B is intended to be placed adjacent to the wearer's undergarments when the sanitary napkin 20 is worn.
  • the sanitary napkin 20 has two centerlines, a principal longitudinal centerline L and a principal transverse centerline T.
  • FIG. 1 shows that the main body portion 22 of the sanitary napkin 20 comprises the portion of the sanitary napkin without the flaps 24.
  • the main body portion 22 has two spaced apart longitudinal edges 26, two spaced apart transverse or end edges (or “ends") 28, which together form the periphery 30 of the main body portion.
  • the main body portion 22 of the sanitary napkin 20 can be of any thickness, including relatively thick, intermediate thickness, relatively thin, or even very thin (or "ultra thin”).
  • An "ultra-thin" sanitary napkin 20 as described in U.S. Patents 4,950,264 and 5,009,653 issued to Osborn preferably has a caliper of less than about 3 millimeters.
  • the embodiment of the sanitary napkin 20 shown in the drawings is intended to be an example of a sanitary napkin of an intermediate thickness.
  • the main body portion 22 of the sanitary napkin 20 may also be relatively flexible, so that it is comfortable for the wearer. It should be understood that the sanitary napkin shown is merely one embodiment, and that the present invention is not limited to absorbent articles of the type or having the specific configurations shown in the drawings.
  • FIG. 2 shows the individual components of the main body portion 22 of the sanitary napkin 20 of the present invention.
  • the main body portion 22 of the sanitary napkin 20 preferably comprises at least three primary components. These include a liquid pervious topsheet 38 typically provided by a liquid permeable substrate of fibrous such as nonwoven or film like structure such as apertured formed films, a liquid impervious backsheet 40 preferably provided by a liquid impermeable, but breathable substrate, and an absorbent core 42 positioned between the topsheet 38 and the backsheet 40.
  • the backsheet 40 comprises two layers; a first layer comprising a gas permeable apertured formed film layer 40A and a second layer comprising a breathable microporous film layer 40B.
  • FIGS. 1 and 2 show a preferred embodiment of the sanitary napkin 20 assembled in a sandwich construction in which the topsheet 38 and the breathable microporous film 40B have length and width dimensions generally larger than those of the absorbent core 42.
  • the topsheet 38 and the breathable microporous film 40B extend beyond the edges of the absorbent core 42 to form portions of the periphery 30.
  • the apertured formed film 40A of the backsheet has the approximately same shape as the absorbent core 42 to cover at least the region where the absorbent core 42 lies as shown in FIG. 2.
  • the apertured formed film 40A does not extend into the flaps 24 as shown in FIG. 2.
  • the apertured formed film 40A may extend into the flaps 24 so that the apertured formed film constitutes a part of the flaps 24.
  • the topsheet 38 is preferably joined to the body-facing side of the absorbent core 42 and the backsheet 40 (i.e., the apertured formed film 40A) is preferably joined to the garment-facing side of the absorbent core 42.
  • the topsheet 38 and the apertured formed film 40A can be joined to the absorbent core 42 in any suitable manner known in the art for this purpose, such as by an open pattern of adhesives.
  • the portions of the topsheet 38 and the breathable microporous film 40B that extend beyond the edges of the absorbent core are preferably also joined to each other.
  • the topsheet 38 and the breathable microporous film 40B can be joined in any suitable manner known in the art for this purpose.
  • these portions of the topsheet 38 and the breathable microporous film 40B are joined using adhesives over substantially the entire portions that extend beyond the edges of the absorbent core 42, and a crimp seal at the end edges 28 of the main body portion where the topsheet 38 and backsheet 40 are densified by the application of pressure or heat and pressure.
  • the sanitary napkin 20 shown in FIGS. 1 and 2 also comprises a pair of flaps 24 that are joined to the main body portion 22 along a juncture, such as lines of juncture 52.
  • the flaps 24 extend laterally outward beyond the longitudinal side edges 26 of the main body portion 22 from their proximal edges to their distal edges (or "free end").
  • the flaps 24 comprise a flap topsheet 44 and a flap backsheet 46.
  • the flaps 24 are integral with the main body portion 22, that is, the flap topsheet 44 and the flap backsheet 46 comprise integral extensions of the topsheet 38 and the breathable microporous film 40B, respectively.
  • the apertured formed film 40A does not extend into the flaps 24.
  • the extensions of the topsheet 38 and the breathable microporous film 40B of the flaps 24 may be joined any suitable method, such as adhesive attachment, ultrasonic attachment, heat attachment or the like.
  • the extensions of the topsheet 38 and the breathable microporous film 40B are joined by applying adhesive to substantially all the region of the flaps 24.
  • the topsheet 38 is preferably compliant, of feeling, and non-irritating to the wearer's skin. Further, the topsheet 38 is fluid pervious, permitting fluid to readily penetrate through its thickness.
  • a suitable topsheet 38 may be manufactured from a wide range of materials such as woven and nonwoven materials; polymeric materials such as apertured formed thermoplastic films, apertured plastic films, and hydroformed thermoplastic films; porous foams; reticulated thermoplastic films; and thermoplastic scrims.
  • Suitable woven and nonwoven materials can be comprised of natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polymeric fibers such as polyester, polypropylene, or polyethylene fibers); or from a combination of natural and synthetic fibers.
  • a preferred topsheet comprises an apertured formed film.
  • apertured formed films are preferably used for the topsheet because they are pervious to body exudates and yet non-absorbent and have a reduced tendency to allow fluids to pass back through and rewet the wearer's skin.
  • the surface of the formed film which is in contact with the body remains dry, thereby reducing body soiling and creating a more comfortable feel for the wearer.
  • Suitable apertured formed films are described in U.S. Patent No. 3,929,135 issued to Thompson, on December 30, 1975; U.S. Patent No. 4,324,246 issued to Mullane et al., on April 13, 1982; U.S. Patent No. 4,342,314 issued to Radel, et al., on August 3, 1982; U.S. Patent No. 4,463,045, issued to Ahr, et al., on July 31 , 1984 and U.S. Pat . No. 5,006,394 issued to Baird, on April 9, 1991.
  • the backsheet 40 is preferably impervious to liquid and pervious to vapor.
  • the primary role of the backsheet 40 is to prevent the extrudes absorbed and contained in the absorbent core 42 from wetting articles that contact the absorbent product such as underpants, pants, pajamas and undergarments.
  • the backsheet 40 also permits the transfer of both vapor and air through it and thus allows the circulation of air into and out of the backsheet 40.
  • the backsheet 40 comprises two layers; a first layer comprising a gas permeable apertured formed film layer 40A and a second layer comprising a breathable microporous film layer 40B.
  • the first layer 40A is typically located adjacent to the absorbent core 42 and subsequent layers of the backsheet are typically located further away from the absorbent core 42.
  • the backsheet 40 may comprise additional layers. All of the layers of the backsheet 40 can be substantially in intimate and direct contact with one another.
  • the first layer of the apertured formed film 40A comprises a layer having discrete apertures 41A which extend beyond the horizontal plane of the garment facing surface of the layer towards the absorbent core 42 thereby forming protuberances 41 B.
  • Each protuberance 41 B has an orifice located at its terminating end.
  • the protuberances 41 B have a funnel or conical shape, similar to those described in US 3,929,135.
  • the apertures located within the plane of the layer and the orifices located at the terminating end of protuberances themselves maybe circular or non circular.
  • the first layer 40A of the backsheet 40 may be made of any material known in the art, but is preferably manufactured from commonly available polymeric materials.
  • the first layer 40A may also comprise any type of formed films which may be used for a topsheet as described above.
  • the second layer 40B of the backsheet 40 may comprise a breathable microporous film composed of a thermoplastic resin and inorganic fillers dispersed in the thermoplastic resin.
  • Suitable thermoplastic polymers include polyolefins such as polyethylenes, including liner low density polyethylene (LLDPE), low density polyethylene (LDPE), ultra low density polyethylene (ULDPE), high density polyethylene (HDPE), or polypropylene and blends thereof with the above and other materials.
  • thermoplastic polymers examples include, but are not limited to, polyester, polyurethanes, compostable or biodegradable polymers, thermoplastic elastomers, and metallocene catalyst-based polymers (e.g., INSITE® available from Dow Chemical Company and Exxact® available from Exxon).
  • the inorganic material or filler is selected from the group consisting of calcium carbonate, clay and titanium dioxide, with the preferred inorganic filler being calcium carbonate.
  • the inorganic filler may be coated with a fatty acid ester to obtain higher loadings in the polymer.
  • the inorganic filler and the thermoplastic polymer are blended together to form a homogeneous mixture in a suitable mixing extruder, or in a separate preliminary compounding step.
  • the mixture is then cast or blown into a film.
  • the obtained film is stretched at least in one direction to impart breathability on the substantially entire area of the film.
  • the step of stretching a film to impart breathability may be done at a different place prior to manufacturing process of absorbent articles. Alternatively, the step of stretching may be done at the same place, i.e., same manufacturing process, prior to assembling a breathable microporous film with other elements of absorbent articles.
  • the film is imparted breathability on the substantially entire area of the film before the resulting breathable microporous film is assembled with other elements of absorbent articles.
  • the absorbent core 42 may be any absorbent means which is generally compressible, conformable, resilient, non-irritating to the wearer's skin and capable of absorbing and containing body exudates.
  • the absorbent core 42 may be manufactured from a wide variety of fluid absorbent materials commonly used in disposable sanitary napkins, and other disposable absorbent articles. Examples of suitable absorbent materials include comminuted wood pulp (which is generally referred to as airfelt), creped cellulose wadding, modified cross- linked cellulose fibers (such as those described in U.S. Patent No. 5,217,445 issued to Young, et al., on June 8, 1993), capillary channel fibers (that is, fibers having intra-fiber capillary channels such as those described in U.S. Patent No.
  • the absorbent core 42 may comprise a first portion and a second portion, the first portion comprising the following components: (a) an optional primary fluid distribution layer preferably together with a secondary optional fluid distribution layer; (b) a fluid storage layer; and the second portion comprising (c) an optional fibrous layer underlying the storage layer; and (d) other optional components.
  • first portion comprising the following components: (a) an optional primary fluid distribution layer preferably together with a secondary optional fluid distribution layer; (b) a fluid storage layer; and the second portion comprising (c) an optional fibrous layer underlying the storage layer; and (d) other optional components.
  • the sanitary napkin 20 shown in FIG. 1 preferably has zones of extensibility (or "zone of differential extensibility") 56 for relieving the stresses on the flaps 24 when they are folded around a panty crotch.
  • the zone of extensibility 56 provides a portion of the sanitary napkin 20 which is capable of extending (and are preferably capable of extending a greater amount than surrounding portions of the sanitary napkin 20).
  • the sanitary napkin 20 may have a hinge 54 between the main body portion 22 and at least a portion of the flaps 24.
  • the hinge 54 provides a region of the sanitary napkin 20 with increased flexibility to create preferred bending axes for the flaps 24 to bend or fold about.
  • the hinge 54 may be imparted extensibility.
  • the zones of extensibility 56 and hinge 54 can, for instance, be formed by a process which has been described as pre-corrugating (or "ring rolling").
  • the zones of extensibility 56 and hinge 54 are provided by at least partly, mechanically straining a base material. Suitable methods for ring rolling are described in U.S. Patent 4,107,364 issued to Sisson on August 15, I978, U.S. Patent 4,834,741 issued to Sabee on May 30, I989, U.S. Patent 5,143,679 issued to Gerald M. Weber, et al. on September 1 , I992, U.S. Patent 5,156,793 issued to Kenneth B. Buell, et al. on October 20, I992, and U.S.
  • Patent 5,167,897 issued to Gerald M. Weber, et al. on December 1 , I992.
  • the zones of extensibility 56 and hinge 54 are provided by forming a strainable network in the region along the juncture 52 of the flaps 24 with the main body portion 22 by mechanically straining a base material.
  • This technology is further described in allowed U.S. Patent Application Serial No. 08/203,087 filed in the name of Chappell, et al. on February 28, 1994 (PCT Publication No. WO 95/03765, published February 9, 1995).
  • a base material into which extensibility is imparted comprises a single layer of material or laminate of materials, at least one of which is a breathable microporous film.
  • the base material (composite sheet) that has extensibility therein comprises a laminate formed by an extension of the topsheet 38 and the breathable microporous film 40B.
  • the ring rolling unit 100 includes intermeshing rolls 101 and 102.
  • the roils 101 , 102 include a plurality of intermeshing teeth 103, 104 respectively on the surfaces of the rolls along the circumferential direction of the rolls 101 , 102.
  • the teeth in this embodiment preferably have a height of 3.175 mm, and are evenly spaced with the centerlines of the teeth spaced apart at 1.9 mm pitches.
  • the entire shape of each toothed regions of the rolls 101 and 102 is generally the same as the entire shape of the zone of extensibility 56 and the hinge 54 of the sanitary napkin 20 shown in FIG. 1.
  • the rolls 101, 102 are arranged so that the teeth 103 and 104 engage to each other as shown in FIG. 6.
  • the engagement of the teeth 103 and 104 is determined based on desired extensibility.
  • the tooth engagement of 2.11 mm, 2.26 mm, and 2.31 mm is preferably used to obtain extensibility of 75%, 80% and 85%.
  • the base material 110 positioned between the rolls 101 and 102 is subjected to a strain (applied strain).
  • the term "applied strain” refers to a strain applied to a material by a process in the direction of extensibility to obtain a residual strain for a predetermined extensibility which will be imparted on the material.
  • the applied strain is described by a strain distribution and its standard deviation of the strain distribution.
  • a portion 110A of the base material 110 between the ridge 103 A of the tooth 103 and the ridge 104A of the tooth 104 is mechanically strained by the applied strain and incrementally and plastically deforms so that a residual strain remains on the base material 110, while portions 110B of the base material 110 on the ridge 103A and 104A are not strained or strained only a little.
  • the base material 110 tends to be strained only at the portion 110A between the ridges on the teeth next to each other and the applied strain is not necessarily applied constantly (the applied strain may be sometimes bigger than a desired applied strain or may be smaller than a desired applied strain), the portion 110A of the base material 110 may be strained exceeding a material strain at break of the base material 110. When this occurs, the base material 110 ruptures.
  • the term "material strain at break” refers to a strain at which a material breaks or ruptures.
  • Extensibility of the zone of extensibility 56 may be from about 50 % to about 100 %. Preferably, extensibility of the zone of extensibility 56 may be from about 65 % to about 90 %.
  • the base material In order to obtain a residual strain for extensibility of, e.g., 75% on the base material, the base material must be strained beyond the residual strain.
  • the base material comprising an apertured formed film which is marketed as Code No. X-15507 by Tredegar Film Products and a polyethylene film which is marketed as Code No. DH-215 Sofflex Blue 240 by Clopay Plastic Products Company needs to be strained up to 210 % to obtain residual strain for extensibility of 75 % on the base material.
  • the base material is capable of being strained up to 210 % without rupturing or creating many visible pin holes.
  • the base material comprising a breathable microporous film may not be capable of such high strain without rupturing or many visible pin holes created because a breathable microporous film is weaker against a strain to obtain a residual strain for extensibility than a non-microporous film and easy to rupture. This is because the breathable microporous film undergoes the "second time" strain for obtaining a residual strain (the "first time strain is applied when stretching a film for imparting breathability). Thus, a breathable microporous film has lower strain at break than a non-microporous film.
  • FIG. 6 shows a relationship between strain distribution for an applied strain (AS) to obtain a residual strain for a predetermined extensibility and strain distribution for a material strain at break (MS).
  • the applied strain and the material strain at break can be measured by the method described below.
  • the applied strain (AS) and the material strain (MS) is descibed by a Gauss curve with standard deviations of GAS and GMS, respectively.
  • the applied strain exceeds the material strain at break.
  • the material ruptures or breaks (or visible pin holes created). Therefore, the less the overlapping area X, the less rupturing or the visible pin holes created occurs.
  • the AS curve can be shifted away from the MS curve, so that the overlapping area of the AS curve and the MS curve is reduced, by changing such as a residual strain for extensiblity. Namely, if the lower extensibility is required, the applied strain to obtain a residual strain for a predetermined extensibility can be lowered.
  • the MS curve can be shifted away from the AS curve by changing material strain at break of a base material. Preferably, the average material strain at break of the base material is at least 300 %. Alternatively, other physical parameters may be changed to reduce the overlapping area of the AS curve and MS curve.
  • the basis weight of a microporous film is another factor to shift the MS curve away from the AS curve.
  • a microporous film has lower strain at break than a non-microporous film. This can be improved by raising the basis weight of the film since the film becomes more capable of being strained without rupturing.
  • the breathable microporous film has a basis weight of 30 g/m 2 or above, it works well to obtain a residual strain for a predetermined extensibility of from about 50 % to about 100%.
  • the breathable microporous film having a basis weight of 35 g/m 2 or above is more preferable.
  • rupturing of the base film is extremely reduced and visible pin holes created are reduced to the level at which the consumers do not see products as defects.
  • the samples used for this measurement are polyethylene film which have grids pattern on surface of film and grids pattern is drawn parallel to and perpendicular to the direction of extensibility which is applied by a process.
  • Grid interval length is preferably 1/20 or less of intermeshing teeth pitch.
  • Samples have suitable width to cover the entire shape of each intermeshing teeth 103 and 104.
  • the sample is the same as microporous film (evaluated film). In the case where the sample material for this test is different from evaluated film, selected sample material properties are similar to the evaluated material.
  • the sample is stretched throughout the ring rolling unit 100 at each required strain rate and each required strain to obtain a residual strain for a predetermined extensibility on the sample.
  • the sample stretched indicates visible strain distribution with a grid pattern transformation. Visible strain distribution on the sample surface of the surface is photographed.
  • Each grid length on the photography parallel to the direction of extensibility which is applied by the ring rolling unit 100 is measured by a steel ruler. Measurement of each grid length is conducted in stretched area.
  • Each grid strain is calculated by the length change from the original grid interval length. Applied strain by the process can be obtained from each grid strain.
  • Measurement method for material strain The tensile test is used for measurement of material strain by measuring force versus percent elongation properties and percent available stretch of material. The tests are performed on an Instron Model 4301 , available from Instron Corporation, which is interfaced to a IBM 330 computer. All essential parameters needed for measuring are input in the MTS software (Testworks 3.07) for each test. Also, all data collection , data analysis and gathering are done using the MTS software.
  • the sample used for this test are 1 inch wide and 4 inches long with the long axis of the sample cut parallel to the direction of extensibility of the sample which is applied by a process.
  • the sample is cut with a sharp exact knife or some suitably sharp cutting device design to cut a precise 1 inch wide sample.
  • the sample is cut so that an area representative of the symmetry of the overall pattern of the deformed region is represented.
  • the grips of the Instron consist of air actuated grips designed to concentrate the entire gripping force along a single line perpendicular to the direction of testing stress having one flat surface and an opposing face from which protrudes a half round to minimize slippage of the sample.
  • the distance between the lines of gripping force should be 2 inches as measured by a steel ruler held beside the grips. This distance will be referred to from hereon as the "gauge length".
  • the sample is mounted in the grips with its long axis perpendicular to the direction of applied percent elongation.
  • the crosshead speed is set to 20 inch/min.
  • the crosshead elongates the sample until the sample breaks at which point the crosshead stops and returns to its original position (0% elongation ).
  • the percent available stretch is the point at which there is an inflection in the force - elongation curve, beyond which point there is rapid increase in the amount of force required to elongate the sample further.
  • the average of the percent available stretch for ten samples
  • a topsheet is an apertured formed film as Code No. X-15507 obtainable from Tredegar Film Products.
  • An absorbent core is the absorbent core used in "Whisper Ultra Slim” manufactured by Procter & Gamble.
  • a backsheet is a breathable microporous film as Code No. PG-OI obtainable from Mitsui Chemical.
  • the breathable microporous film has a basis weight of 35 g/m 2 and average material strain at break of 563.9 % with standard deviation of 25.3. Flaps of the sanitary napkins are made of the extensions of the apertured formed film and the microporous film.
  • the apertured formed film and the microporous film constituting the flaps are joined by an adhesive (Nitta Findley Co., Ltd.; code No. H-4031).
  • the sample is processed by the process described in FIGS. 4 - 6 under the condition of average applied strain of 210 % with standard deviation of 48.3 to obtain 75 % extensibility on the flaps. (Ex
  • the breathable microporous film has a basis weight of 35 g/m 2 average material strain at break of 579 % with standard deviation 17.3.
  • the sample is processed under the condition of average applied strain of 219 % with standard deviation of 50.4 to obtain 80 % extensibility on the flaps.
  • the other structures are the same as the Example 1.
  • Example 3 The breathable microporous film has a basis weight of 35 g/m 2 average material strain at break of 580 % with standard deviation 18.2. The sample is processed under the condition of average applied strain of 232 % with standard deviation of 53.4 to obtain 85 % extensibility on the flaps.
  • the other structures are the same as the Example 1.
  • the breathable microporous film has a basis weight of 35 g/m 2 average material strain at break of 545.3 % with standard deviation 27.4.
  • the sample is processed under the condition of average applied strain of 210 % with standard deviation of 48.3 to obtain 75 % extensibility on the flaps.
  • the other structures are the same as the Example 1.
  • the breathable microporous film has a basis weight of 35 g/m 2 average material strain at break of 548.6 % with standard deviation 18.2.
  • the sample is processed under the condition of average applied strain of 232 % with standard deviation of 53.4 to obtain 85 % extensibility on the flaps.
  • the other structures are the same as the Example 1.
  • the breathable microporous film has a basis weight of 40 g/m 2 average material strain at break of 584 % with standard deviation 16.5.
  • the sample is processed under the condition of average applied strain of 210 % with standard deviation of 48.3 to obtain 75 % extensibility on the flaps.
  • the other structures are the same as the Example 1. (Example 7)
  • the breathable microporous film has a basis weight of 40 g/m 2 average material strain at break of 577.4 % with standard deviation 14.8.
  • the sample is processed under the condition of average applied strain of 232 % with standard deviation of 53.4 to obtain 85 % extensibility on the flaps.
  • the other structures are the same as the Example 1.
  • Example 8 The breathable microporous film has a basis weight of 40 g/m 2 average material strain at break of 627.6 % with standard deviation 21.9. The sample is processed under the condition of average applied strain of 210 % with standard deviation of 48.3 to obtain 75 % extensibility on the flaps.
  • the other structures are the same as the Example 1.
  • the breathable microporous film has a basis weight of 40 g/m 2 average material strain at break of 616.0 % with standard deviation 18.0.
  • the sample is processed under the condition of average applied strain of 210 % with standard deviation of 48.3 to obtain 75 % extensibility on the flaps.
  • the other structures are the same as the Example 1.

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  • Health & Medical Sciences (AREA)
  • Epidemiology (AREA)
  • Vascular Medicine (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Dermatology (AREA)
  • Absorbent Articles And Supports Therefor (AREA)

Abstract

L'invention concerne un article absorbant à rabats. Cet article absorbant comporte une feuille supérieure, un feuille inférieure et une partie centrale absorbante située entre les deux. La feuille inférieure comporte un film microporeux imper-respirant. On fabrique ce film microporeux imper-respirant en étirant un mélange d'une résine thermoplastique et de charges inorganiques dans au moins un sens. Les rabats sont constitués par une feuille composite comportant une feuille supérieure de rabat et un prolongement du film microporeux imper-respirant. On confère aux rabats une extensibilité prédéterminée. La feuille inférieure est imper-respirante sur sensiblement toute sa surface. Le film microporeux imper-respirant présente une masse surfacique d'au moins 30 g/m2. On confère à une partie au moins de la feuille composite l'extensibilité prédéterminée en soumettant à des contraintes au moins un partie du film microporeux imper-respirant. L'extensibilité prédéterminée est comprise entre environ 50 % et environ 100 %.
PCT/US1998/004651 1998-03-10 1998-03-10 Article absorbant a rabats comportant un film microporeux extensible WO1999045873A1 (fr)

Priority Applications (14)

Application Number Priority Date Filing Date Title
PCT/US1998/004651 WO1999045873A1 (fr) 1998-03-10 1998-03-10 Article absorbant a rabats comportant un film microporeux extensible
AU65477/98A AU6547798A (en) 1998-03-10 1998-03-10 Absorbent article with flaps comprising microporous film having extensibility
PCT/US1998/023029 WO1999045871A1 (fr) 1998-03-10 1998-10-29 Article absorbant muni d'un film microporeux
AT98955201T ATE235206T1 (de) 1998-03-10 1998-10-29 Absorbierender artikel mit einen microporösen film
DE69812718T DE69812718T2 (de) 1998-03-10 1998-10-29 Absorbierender artikel mit einen microporösen film
US09/623,814 US6328723B1 (en) 1998-03-10 1998-10-29 Absorbent article comprising microporous film
CA002322455A CA2322455C (fr) 1998-03-10 1998-10-29 Article absorbant muni d'un film microporeux
EP98955201A EP1061879B1 (fr) 1998-03-10 1998-10-29 Article absorbant muni d'un film microporeux
JP2000535287A JP4509379B2 (ja) 1998-03-10 1998-10-29 微孔質フィルムを備えた吸収体
KR10-2000-7009978A KR100489858B1 (ko) 1998-03-10 1998-10-29 미세기공 필름을 포함하는 흡수 제품
ES98955201T ES2191975T3 (es) 1998-03-10 1998-10-29 Articulo absorbente que comprende una pelicula microporosa.
AU12063/99A AU1206399A (en) 1998-03-10 1998-10-29 Absorbent article comprising microporous film
CNB988138395A CN1243523C (zh) 1998-03-10 1998-10-29 包含微孔薄膜的吸湿用品
BR9815687-0A BR9815687A (pt) 1998-03-10 1998-10-29 Artigo absorvente dotado de uma pelìcula microporosa respirável

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1998/004651 WO1999045873A1 (fr) 1998-03-10 1998-03-10 Article absorbant a rabats comportant un film microporeux extensible

Publications (1)

Publication Number Publication Date
WO1999045873A1 true WO1999045873A1 (fr) 1999-09-16

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AU (1) AU6547798A (fr)
WO (1) WO1999045873A1 (fr)

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4923650A (en) 1988-07-27 1990-05-08 Hercules Incorporated Breathable microporous film and methods for making it
JPH05230252A (ja) 1992-02-19 1993-09-07 Kao Corp 多孔性シート及びその製造方法
JPH0662794B2 (ja) 1986-04-28 1994-08-17 花王株式会社 多孔性フイルムまたはシ−トの製造方法
JPH07231913A (ja) 1993-12-28 1995-09-05 Kao Corp 多孔性シート及びその製法並びにそれを用いた吸収性物品
JPH08225680A (ja) 1995-11-10 1996-09-03 Mitsui Toatsu Chem Inc 多孔性フィルム又はシート
JPH08300436A (ja) 1995-05-02 1996-11-19 Kao Corp 多孔性シート及びその製法並びにそれを用いた吸収性物品
JPH08300498A (ja) 1995-05-11 1996-11-19 Kao Corp 多孔性シート及びその製造方法並びに該多孔性シートを用いた吸収性物品
JPH08300499A (ja) 1995-05-11 1996-11-19 Kao Corp 多孔性シート及びその製造方法並びに該多孔性シートを用いた吸収性物品
WO1997012577A1 (fr) * 1995-10-06 1997-04-10 The Procter & Gamble Company Articles absorbants presentant des rabats, des decrochements et des zones d'extension
WO1997026850A1 (fr) * 1996-01-24 1997-07-31 Mcneil-Ppc, Inc. Tissu de renforcement pour article absorbant
US5691035A (en) * 1993-08-03 1997-11-25 The Procter & Gamble Company Web materials exhibiting elastic-like behavior
WO1997047264A1 (fr) * 1996-06-11 1997-12-18 The Procter & Gamble Company Materiau en feuille souple a ondulation biaxiale pour articles absorbants
WO1997048358A1 (fr) * 1996-06-21 1997-12-24 Kimberly-Clark Worldwide, Inc. Article absorbant avec couche exterieure composite permeable a l'air

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0662794B2 (ja) 1986-04-28 1994-08-17 花王株式会社 多孔性フイルムまたはシ−トの製造方法
US4923650A (en) 1988-07-27 1990-05-08 Hercules Incorporated Breathable microporous film and methods for making it
JPH05230252A (ja) 1992-02-19 1993-09-07 Kao Corp 多孔性シート及びその製造方法
US5691035A (en) * 1993-08-03 1997-11-25 The Procter & Gamble Company Web materials exhibiting elastic-like behavior
JPH07231913A (ja) 1993-12-28 1995-09-05 Kao Corp 多孔性シート及びその製法並びにそれを用いた吸収性物品
JPH08300436A (ja) 1995-05-02 1996-11-19 Kao Corp 多孔性シート及びその製法並びにそれを用いた吸収性物品
JPH08300498A (ja) 1995-05-11 1996-11-19 Kao Corp 多孔性シート及びその製造方法並びに該多孔性シートを用いた吸収性物品
JPH08300499A (ja) 1995-05-11 1996-11-19 Kao Corp 多孔性シート及びその製造方法並びに該多孔性シートを用いた吸収性物品
WO1997012577A1 (fr) * 1995-10-06 1997-04-10 The Procter & Gamble Company Articles absorbants presentant des rabats, des decrochements et des zones d'extension
JPH08225680A (ja) 1995-11-10 1996-09-03 Mitsui Toatsu Chem Inc 多孔性フィルム又はシート
WO1997026850A1 (fr) * 1996-01-24 1997-07-31 Mcneil-Ppc, Inc. Tissu de renforcement pour article absorbant
WO1997047264A1 (fr) * 1996-06-11 1997-12-18 The Procter & Gamble Company Materiau en feuille souple a ondulation biaxiale pour articles absorbants
WO1997048358A1 (fr) * 1996-06-21 1997-12-24 Kimberly-Clark Worldwide, Inc. Article absorbant avec couche exterieure composite permeable a l'air

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