JP2004181087A - Absorbent article having liquid trapping layer - Google Patents

Absorbent article having liquid trapping layer Download PDF

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Publication number
JP2004181087A
JP2004181087A JP2002354186A JP2002354186A JP2004181087A JP 2004181087 A JP2004181087 A JP 2004181087A JP 2002354186 A JP2002354186 A JP 2002354186A JP 2002354186 A JP2002354186 A JP 2002354186A JP 2004181087 A JP2004181087 A JP 2004181087A
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Japan
Prior art keywords
liquid
layer
topsheet
acquisition layer
absorbent article
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JP2002354186A
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Japanese (ja)
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JP4323787B2 (en
Inventor
Atsushi Kudo
淳 工藤
Masahiro Kashiwagi
政浩 柏木
Masataka Kinoshita
正隆 木下
Kenichiro Kuroda
賢一郎 黒田
Takuya Miyama
拓也 深山
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Unicharm Corp
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Unicharm Corp
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Priority to JP2002354186A priority Critical patent/JP4323787B2/en
Application filed by Unicharm Corp filed Critical Unicharm Corp
Priority to AU2003284530A priority patent/AU2003284530A1/en
Priority to KR1020057005931A priority patent/KR101078105B1/en
Priority to PCT/JP2003/015389 priority patent/WO2004049998A1/en
Priority to CNB2003801008142A priority patent/CN100450465C/en
Priority to TW92134217A priority patent/TWI231202B/en
Priority to MYPI20034642 priority patent/MY131925A/en
Publication of JP2004181087A publication Critical patent/JP2004181087A/en
Priority to US11/059,058 priority patent/US7132585B2/en
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Publication of JP4323787B2 publication Critical patent/JP4323787B2/en
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    • 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
    • A61F13/475—Sanitary towels, incontinence pads or napkins characterised by edge leakage prevention means
    • A61F13/4751—Sanitary towels, incontinence pads or napkins characterised by edge leakage prevention means the means preventing fluid flow in a transversal direction
    • A61F13/4756—Sanitary towels, incontinence pads or napkins characterised by edge leakage prevention means the means preventing fluid flow in a transversal direction the means consisting of grooves, e.g. channels, depressions or embossments, resulting in a heterogeneous surface level
    • 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
    • A61F13/53—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 absorbing medium
    • A61F13/534—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 absorbing medium having an inhomogeneous composition through the thickness of the pad
    • A61F13/537—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 absorbing medium having an inhomogeneous composition through the thickness of the pad characterised by a layer facilitating or inhibiting flow in one direction or plane, e.g. a wicking layer
    • A61F13/53708—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 absorbing medium having an inhomogeneous composition through the thickness of the pad characterised by a layer facilitating or inhibiting flow in one direction or plane, e.g. a wicking layer the layer having a promotional function on liquid propagation in at least one direction
    • A61F13/53713—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 absorbing medium having an inhomogeneous composition through the thickness of the pad characterised by a layer facilitating or inhibiting flow in one direction or plane, e.g. a wicking layer the layer having a promotional function on liquid propagation in at least one direction the layer having a promotional function on liquid propagation in the vertical direction
    • 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
    • A61F13/53—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 absorbing medium
    • A61F13/534—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 absorbing medium having an inhomogeneous composition through the thickness of the pad
    • A61F13/537—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 absorbing medium having an inhomogeneous composition through the thickness of the pad characterised by a layer facilitating or inhibiting flow in one direction or plane, e.g. a wicking layer
    • A61F13/53743—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 absorbing medium having an inhomogeneous composition through the thickness of the pad characterised by a layer facilitating or inhibiting flow in one direction or plane, e.g. a wicking layer characterised by the position of the layer relative to the other layers
    • A61F13/53747—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 absorbing medium having an inhomogeneous composition through the thickness of the pad characterised by a layer facilitating or inhibiting flow in one direction or plane, e.g. a wicking layer characterised by the position of the layer relative to the other layers the layer is facing the topsheet
    • 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
    • A61F13/53—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 absorbing medium
    • A61F13/534—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 absorbing medium having an inhomogeneous composition through the thickness of the pad
    • A61F13/537—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 absorbing medium having an inhomogeneous composition through the thickness of the pad characterised by a layer facilitating or inhibiting flow in one direction or plane, e.g. a wicking layer
    • A61F2013/53765—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 absorbing medium having an inhomogeneous composition through the thickness of the pad characterised by a layer facilitating or inhibiting flow in one direction or plane, e.g. a wicking layer characterized by its geometry
    • A61F2013/53778—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 absorbing medium having an inhomogeneous composition through the thickness of the pad characterised by a layer facilitating or inhibiting flow in one direction or plane, e.g. a wicking layer characterized by its geometry with grooves

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  • Health & Medical Sciences (AREA)
  • Epidemiology (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Vascular Medicine (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Absorbent Articles And Supports Therefor (AREA)
  • Orthopedics, Nursing, And Contraception (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbent article constituted so as to temporarily hold menstrual blood under the surface sheet of the absorbent article when a large amount of the menstrual blood is applied to the surface sheet of the absorbent article to rapidly transfer this menstrual blood to a liquid absorbing layer. <P>SOLUTION: Liquid permeating holes 25 which pierce the surface sheet 3 and a liquid permeable layer 5, are formed at the central region 20 of a sanitary napkin 1, and a liquid trapping layer 6 which is formed by forming a water absorbing sheet 8 into a three-dimensional shape, is provided under the central region. The liquid trapping layer 6 has lengthwise ribs 6a extending in a lengthwise direction, slightly low lateral ribs 6b for connecting the lengthwise ribs 6a and recessed parts 6c surrounded by the lengthwise ribs 6a and the lateral ribs 6b. The menstrual blood permeated through the liquid permeating holes 25 is held by the recessed parts 6c and rapidly absorbed by the liquid absorbing layer 4 from the bottom parts of the recessed parts 6c. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、女性性器から排泄される経血などの吸収に適した吸収性物品に係り、特に、表面シートと液吸収層との間に、液を吸収して前記液吸収層に与える液獲得層が設けられた吸収性物品に関する。
【０００２】
【従来の技術】
女性性器から排泄される経血を吸収する吸収性物品の一般的な構造は、肌側表面に位置する液透過性の表面シートと、着衣側表面に位置する液不透過性の裏面シートと、前記表面シートと裏面シートの間に介在する液吸収層とを有するものであり、通常は下着のクロッチ布の内面に前記裏面シートが感圧接着層を介して接着された状態で着用される。
【０００３】
この種の吸収性物品では、表面シートに一時に多量の経血が与えられると、表面シートに経血が長時間残ることになって、股間部に湿潤感を与え着用者に不快を与えることになる。そこで、一時に多量の液体が与えられたときに、その液体を表面シートの下で拡散させたり、表面シートの下で保持させる工夫がなされたものがある。
【０００４】
以下の特許文献１には、表面シートと液吸収層との間に、液体搬送帯が設けられた生理用ナプキンが開示されている。
【０００５】
前記液体搬送帯は、不織布に凹状のスクリーンパターンを多数形成したものである。このスクリーンパターンは、所定の厚みの不織布を一方の面から圧縮して高繊維密度部を形成したエンボスパターン、および前記不織布を両面から圧縮して薄膜要素を形成したエンボスパターンであり、これら両エンボスパターンが生理用ナプキンの縦方向（長手方向）に向けて配列されている。この液体搬送帯は、表面シートを透過した経血の移動を、前記薄膜要素で規制して前記高繊維密度部を通るように迂回させ、これにより経血を縦方向に拡散させて、表面シートでの液残りを防止しようとするものである。
【０００６】
次に、特許文献２は、使い捨ておむつにおいて、表面シートと液吸収層との間に、液透過性シートを介在させたものが開示されている。
【０００７】
前記液透過性シートは、不織布や紙が立体的に変形させられて、多数の凹部とこの凹部を仕切る網目状の凸部とが形成されている。この使い捨ておむつは、一度に多量の液が与えられたときに、前記液透過性シートの凹部で液を一旦保持することで、液がおむつの面に沿って流れるのを防止しようとするものである。
【０００８】
【特許文献１】
特開平６−３８９９８号公報
【特許文献２】
特開２０００−１４００１５号公報
【０００９】
【発明が解決しようとする課題】
前記特許文献１に記載の液体搬送帯は、表面シートを透過した液を長手方向に拡散させることができるかもしれないが、液体搬送帯そのものの液体の保持能力および液体の透過能力が低いために、液体搬送帯に多量の経血が与えられるとすぐに飽和して滞留しやすい。すなわち、この液体搬送帯は、メルトブロウ不織布などにエンボスパターンを形成したものであるが、メルトブロウ不織布は平坦な状態のまま使用されているため、それ自体が局部的に与えられた多量の液体を保持できるものではない。まして、前記不織布に形成したエンボスパターンはその凹部の空間容積がきわめて微小であるため、エンボスパターンの凹部内においても液体をほとんど保持することができない。それどころか、メルトブロウ不織布自体が密度が高く液体の透過性が劣るのに加えて、さらに前記薄膜要素で液体の透過を遮断しているため、液体の透過能力が低い。
【００１０】
次に、特許文献２に記載の液透過性シートは、三角形の凹部に尿を溜めて、平面的に拡散するのを抑制しようとしているが、網目状の凸部により液体の拡散を抑制しているために、前記凹部内で尿がすぐに飽和してしまう。よって、この液透過性シートを生理用ナプキンに適用した場合、尿よりも粘度の高い経血が前記凹部に集中すると、この凹部内で滞留しやすい。また、特許文献２では、前記液透過性シートの好ましい例として紙で形成されるものとなっているが、このような紙で形成された液透過性シートを生理用ナプキンに用いた場合、股間部から与えられる圧力により直ちに凹部が潰れてしまい、また生理用ナプキンに位置ずれ力が作用したときに液透過性シートが破れやすい。
【００１１】
本発明は上記従来の課題を解決するものであり、多量の液体が与えられたときにこれを一時的に保持できるとともに、液吸収層にスムーズに移行させることができ、表面シートでの液残りを低減させることのできる吸収性物品を提供することを目的としている。
【００１２】
【課題を解決するための手段】
本発明は、肌側表面に位置する液透過性の表面シートと、着衣側表面に位置する裏面シートと、前記表面シートと前記裏面シートとの間に位置する液吸収層とを備えた縦長の吸収性物品において、
前記液吸収層の前記表面シートに向く表面に液獲得層が設置されており、前記液獲得層は、吸水性シートが、その厚み方向に向けて立体的に変形した状態を保つものであり、
その立体形状は、前記表面シートに向けて凸状で且つ縦方向に延びる縦リブが互いに平行に形成されているとともに、前記表面シートに向けて凸状で且つ横方向に延びる横リブが、縦方向に間隔を開けて前記縦リブ間を繋ぐように形成され、前記縦リブと横リブとで囲まれた多数の凹部が前記液吸収層に向けて窪んで形成されており、
少なくとも前記縦リブが、前記表面シートに接し、あるいは表面シートの下に位置する液透過層に接し、前記凹部の底部が前記液吸収層に接していることを特徴とするである。
【００１３】
本発明の吸収性物品では、表面シートを透過した経血が液獲得層に形成された凹部内に一時的に保持されるが、液獲得層は吸水性シートを立体的に変形させたものであるため、不織布に形成されたエンボスパターンに比較して凹部の空間容積を大きくでき、凹部内に多くの経血を一時的に保持できる。しかも吸水性シートで形成された凹部の底部が液吸収層に接しているため、凹部内の経血は吸水性シートを透過して直ちに液吸収層に移行でき、凹部内で長期間経血が溜まるのを防止できる。また、縦リブが物品の長手方向である縦向きに延び、この縦リブが表面シートや液透過層に接しているため、凹部に保持された液が縦方向に向けて案内され、横方向への拡散が抑制されやすくなる。よって経血は横方向への漏れを生じること無く液吸収層に浸透しやすくなる。
【００１４】
また、本発明は、前記凹部の底部から前記横リブの頂部までの高さ寸法が、前記凹部の底部から前記縦リブの頂部までの高さ寸法よりも低いものである。
【００１５】
この液獲得層は、経血を凹部内で受けて直ちに液吸収層に浸透させるものであるが、仮に凹部内に一時に多量の経血が与えられたとしても、この経血が低い横リブを越えて縦方向に並ぶ凹部に移行できるため、横方向への拡散を防止しやすい。
【００１６】
そのためには、それぞれの前記凹部は、横方向の幅寸法よりも縦方向の長さ寸法が長い縦長であることが好ましい。
【００１７】
また本発明では、１つの凹部の空間容積が８〜８０ｍｍ３であることが好ましい。
【００１８】
１つの凹部の空間容積が前記範囲内であると、粘度の高い体液である経血が、液獲得層を透過するまでの間、凹部が経血を保持することができ、多くの経血が短時間に与えられたとしても、この経血が凹部からあふれることが少なくなり、経血が表面シートに戻るのを防止でき、また経血が横方向へ拡散するのを防止できる。
【００１９】
また、本発明では、前記液獲得層は、前記吸水性シートが立体的に変形させられる際の引っ張り応力の集中により繊維間の間隔が広げられて低密度とされた部分を有するものである。
【００２０】
前記液獲得層に繊維密度が低くなっている部分が形成されていると、凹部内に一時的に保持された経血を直ちに液吸収層に移行させることができる。
【００２１】
また本発明は、前記液獲得層には、前記縦リブよりも幅が広い平坦部が、縦方向に連続して形成されているものである。
【００２２】
前記平坦部は、立体形状に成形する際の引っ張り力や圧縮力を受けない領域であり、強度が低下しておらず、また繊維密度が元の材質のままであり縦リブなどに比べて密度が低い領域となる。よって、吸収性物品を組み立てる際に、この平坦部を保持して液獲得層を組み立て工程に供給することができる。またこの平坦部は縦リブなどに比較して低い密度を維持できるため、この平坦部が縦方向に延びていると、この平坦部は経血が横方向に拡散するのを防止する拡散防止帯として機能できる。この平坦部は、液獲得層のどの位置に設けられていてもよいが、前記拡散防止帯としての機能を効果的に発揮させるためには、前記平坦部は液獲得層の両側部に形成されていることが好ましい。また平坦部が液獲得層の前後端部に設けられていてもよい。
【００２３】
また本発明では、前記液獲得層は、複数枚の前記吸水性シートが重ねられて少なくとも一部で吸水性シートどうしが接着され、この複数枚の吸水性シートが一緒に前記立体形状とされたものとして構成できる。
【００２４】
液獲得層を複数枚の吸水性シートで構成すると、目付けを高くできて液の吸収保持能力が高くなり、さらに縦リブや横リブの強度を高くできる。さらに凹部の壁部が低密度となりあるいは亀裂が生じても、この壁部が複数枚のシートで形成されていると、低密度の部分や亀裂が形成される部分が一箇所に集中しなくなり、前記壁部の強度の極端な低下を防止できる。よって、吸収性物品が湿潤状態となったときにも、凹部の形状を常に維持できるようになる。
【００２５】
また、本発明では、乾燥状態の前記液獲得層を縦方向に引っ張ったときの破断強度が２５ｍｍ幅あたり２．５Ｎ以上であることが好ましい。
【００２６】
前記強度を有ししかも吸水機能を発揮するためには、吸水性シートはセルロース系繊維と合成樹脂繊維とで形成されていることが好ましい。また、前記強度を有すると、身体からの圧力を受けても立体形状を保ちやすく、凹部の空間容積を長期間維持できるようになる。
【００２７】
【発明の実施の形態】
本発明の吸収性物品は、女性の膣口から排泄される経血を吸収することを主な目的とする生理用ナプキンとして使用される。また吸収性物品の２つの表面のうち股間部に向けられる表面を肌側表面とし、反対側の表面は、その外側に着衣が着用されるか否かに拘らず着衣側表面と表現する。
【００２８】
本明細書での縦方向中心線とは、吸収性物品を横方向に二分して縦方向に延びる線を意味する。一方、以下の第１の実施の形態では吸収性物品を縦方向に二分する横方向に延びる線を横方向基準線としているが、この横方向基準線は必ずしも吸収性物品を縦方向に二分する位置を横断していることを意味せず、例えば第２の実施の形態のように女性が就寝時に着用するのに適した縦方向に長い吸収性物品であって、ウイング部が前方部分に位置しているものでは、肌側表面を身体に装着したときに、膣口に当たる部分での縦方向の中心を通る線を横方向基準線とする。
【００２９】
図１は本発明の吸収性物品の第１の実施の形態として生理用ナプキン１を肌側表面を上向きにして示した平面図、図２は、図１の生理用ナプキンが下着のクロッチ布に取り付けられた状態を示すものであり、横方向基準線で切断したＩＩ−ＩＩ矢視の断面図、図３は前記生理用ナプキンの中央領域を示す拡大断面図、図４は液獲得層を示す斜視図、図５は図４をＶ−Ｖ線で切断した断面図、図６は図４をＶＩ−ＶＩ線で切断した断面図である。
【００３０】
生理用ナプキン１は、縦方向中心線Ｏｙ−Ｏｙから横方向に等距離を開けて縦方向に延びる右側縁部１ａと左側縁部１ｂを有し、横方向基準線Ｏｘ−Ｏｘから前後に等間隔を開けた凸曲線形状の前縁部１ｃおよび後縁部１ｄを有している。
【００３１】
前記右側縁部１ａと左側縁部１ｂは、横方向基準線Ｏｘ−Ｏｘを含む縦方向の所定の長さ範囲において左右両側に突出し、この突出部分でウイング部１Ａ，１Ａが形成されている。
【００３２】
図２の断面図に示すように、この生理用ナプキン１は、着衣側表面に現れる液不透過性の裏面シート２と、肌側表面に現れる液透過性の表面シート３を有している。前記裏面シート２と前記表面シート３との間には液吸収層４が介在している。表面シート３の下には液透過層５が設けられ、液透過層５と前記液吸収層４との間に液獲得層６が設けられている。
【００３３】
生理用ナプキン１は、少なくとも表面シート３と前記液吸収層４とが局部的に加圧され且つ加熱されて、肌側表面に現れる圧縮溝１０が形成されている。この圧縮溝１０は、加熱ロールを用いたエンボス加工によって形成される。前記液吸収層４と表面シート３が重ねられた状態で、液吸収層４の表面にフラット面の加熱ロールが当てられ、表面シート３の表面にエンボスパターンの凸部を有する加熱ロールが当てられて、加圧され且つ加熱されて圧縮溝１０が形成される。
【００３４】
前記圧縮溝１０では、前記液吸収層４および表面シート３がほぼフィルム状に圧着された高密度圧縮部と、フィルム状にはなっていないが圧縮溝１０以外の領域よりも高密度となった中密度圧縮部とが、交互に形成されている。この高密度圧縮部と中密度圧縮部とを有する圧縮溝が、生理用ナプキン１の肌側表面から裏面シート２側へ窪む凹溝として形成されている。
【００３５】
図１に示すように、前記圧縮溝１０は符号１１ないし１６で示す各圧縮溝に区分される。
【００３６】
縦方向中心線Ｏｙ−Ｏｙから右側と左側に等距離を開けた位置に、縦方向に延びる内側圧縮溝１１，１１が形成されている。前記内側圧縮溝１１，１１は、横方向基準線Ｏｘ−Ｏｘの部分でその対向間隔が狭くなるように、縦方向中心線Ｏｙ−Ｏｙに凸側が向けられる円弧曲線となっている。前記内側圧縮溝１１と内側圧縮溝１１は、前方連結圧縮溝１２と後方連結圧縮溝１３により互いに連結されている。前方連結圧縮溝１２は、前縁部１ｃに凸側が向けられる曲線形状であり、後方連結圧縮溝１３は後縁部１ｄに凸側が向けられる曲線形状である。
【００３７】
前記内側圧縮溝１１，１１と前記前方連結圧縮溝１２との交点から、前縁部１ｃに向けて一対の前方延長圧縮溝１４，１４が形成されており、この前方延長圧縮溝１４，１４は、縦方向中心線Ｏｙ−Ｏｙに対して左右に等距離に配置されている。また、内側圧縮溝１１，１１と前記後方連結圧縮溝１３との交点から、後縁部１ｄに向けて一対の後方延長圧縮溝１５，１５が形成されている。この後方延長圧縮溝１５，１５は、縦方向中心線Ｏｙ−Ｏｙに対して左右に等距離に配置されている。
【００３８】
前記内側圧縮溝１１，１１、前方連結圧縮溝１２、後方連結圧縮溝１３、前方延長圧縮溝１４，１４、および後方延長圧縮溝１５，１５は、全て連続して形成されている。また、前記内側圧縮溝１１，１１、前方連結圧縮溝１２、および後方連結圧縮溝１３により、生理用ナプキン１の肌側表面の所定範囲が囲まれて、この囲まれた範囲が中央領域２０となっている。この中央領域２０は、縦方向中心線Ｏｙ−Ｏｙに対して左右対称形状であり、また横方向基準線Ｏｘ−Ｏｘに対しても前後に対称形状である。
【００３９】
内側圧縮溝１１，１１の左右両外側には、外側圧縮溝１６，１６が形成されている。この外側圧縮溝１６，１６は、前記横方向基準線Ｏｘ−Ｏｘを中心として縦方向の前後の所定長の範囲に形成されている。前記外側圧縮溝１６，１６は、前記内側圧縮溝１１，１１と相似の曲線形状であり、内側圧縮溝１１，１１と一定の間隔を保って形成されている。
【００４０】
図１に示すように、前記液透過層５は、縦方向に細長い帯状であり、その両側縁部５ａ，５ａは左右の内側圧縮溝１１，１１と重複することがなく、前記内側圧縮溝１１，１１の内側に位置している。また液透過層５は、前方連結圧縮溝１２を超えて前縁部１ｃまで延びており、且つ後方連結圧縮溝１３を超えて後縁部１ｄまで延びている。前記前方連結圧縮溝１２と後方連結圧縮溝１３の一部で、表面シート３と前記液吸収層５および液吸収層４が一緒に圧縮されている。
【００４１】
前記液獲得層６は長方形であり、両側縁部６ｈ，６ｈは、前記内側圧縮溝１１，１１を超えて左右外側に位置している。また前縁部６ｉと後縁部６ｊは、前方連結圧縮溝１２および後方連結圧縮溝１３よりも横方向基準線Ｏｘ−Ｏｘに近い位置にある。前記内側圧縮溝１１，１１の一部において、前記表面シート３と液獲得層６および液吸収層４が一緒に圧縮されている。
【００４２】
前記中央領域２０には、多数の液透過孔２５が規則的に配列して設けられている。図３に示すように、前記液透過孔２５が、表面シート３を貫通して液透過層５に至るように形成されており、好ましくは前記液透過孔２５が、表面シート３から液透過層２５を貫通して形成されている。また、液透過層５の側縁部５ａ，５ａから外れる部分では、前記表面シート３のみに液透過孔２５が形成されている。
【００４３】
前記液透過孔２５の開孔面積は０．２〜８ｍｍ２であり、この実施の形態では円形の液透過孔２５の直径が０．５〜３．２ｍｍである。隣接する液透過孔２５の中心間距離は１．５〜８ｍｍである。
【００４４】
前記表面シート３と液透過層５は熱融着が可能な熱可塑性繊維を含んでいる。表面シート３と液透過層５とが重ねられた状態で、表面シート３から液透過層５側に向けて前記針またはピンを差し込んで、抜き取ることにより液透過孔２５が形成される。液透過孔５の内面およびその周囲では、表面シート３に含まれる熱可塑性繊維と、液透過層５に含まれる熱可塑性繊維とが互いに融着される。これにより、液透過孔２５の開孔形状を維持できるとともに、液透過層５によって液透過孔２５の開孔周囲が補強される。また前記熱融着によって表面シート３と液透過層５とが接合されるため、表面シート３と液透過層５とを接着剤で接着する必要が無くなり、接着剤によって液の透過が阻害されることがない。
【００４５】
前記表面シート３は、エアースルー不織布で形成される。このエアースルー不織布は、芯部が酸化チタンを含んだポリエチレンテレフタレート（ＰＥＴ）で、鞘部がポリエチレン（ＰＥ）の芯鞘型複合合成繊維を用い、この繊維を熱風によって接合したものであり、目付けは１５〜６０ｇ／ｍ２程度である。また表面シート３を構成している前記複合合成繊維は、親水性油剤がコーティングされたものと、撥水性油剤がコーティングされたものとが混合されたものであり、撥水性油剤がコーティングされた繊維の混合率は１０〜３０質量％である。表面シート３に撥水性油剤がコーティングされた繊維を前記混合率となるように均一に含ませることで、表面シート３に与えられた経血が表面シート３内で拡散しすぎるのを抑制でき、経血は主に液透過孔２５を透過して液吸収層４に与えられるようになる。
【００４６】
ただし、前記表面シート３は液透過孔２５以外の領域でも経血を液透過層５に向けて透過させることができる。このような液透過機能を発揮するためには、表面シート３の密度は０．１２ｇ／ｃｍ３以下であることが好ましく、その下限は０．０２５ｇ／ｃｍ３程度である。
【００４７】
液透過層５は、芯部がポリプロピレン（ＰＰ）で鞘部がポリエチレン（ＰＥ）の芯鞘型複合合成繊維で形成されたエアースルー不織布で形成される。液透過層５のエアースルー不織布は、親水性油剤がコーティングされた繊維のみで形成され、撥水性油剤がコーティングされた繊維は含まれていない。図３に示す実施の形態では、液透過層５は前記エアースルー不織布を複数枚重ねて構成されており、例えば１枚のエアースルー不織布が２枚重ね３枚重ねあるいは４枚重ねとなるように折り畳まれたものが使用される。１枚のエースルー不織布の目付けは１５〜５０ｇ／ｍ２程度であり、液透過層５全体の目付けは３０〜１５０ｇ／ｍ２程度であればよく、さらに好ましくは５０〜１００ｇ／ｍ２である。
【００４８】
液透過層５の目付けを表面シート３の目付けよりも大きくすることにより、目付けおよび密度の低い表面シート３を補強でき、表面シート３に過大な皺が生じたり液透過孔２５の部分から破れを生じることなどを防止できる。
【００４９】
液透過層５の繊維密度は表面シート３の繊維密度よりも低く、液透過層５の繊維密度は０．０１６〜０．０８ｇ／ｃｍ３である。また、例えば、表面シート３は繊度が２．２ｄｔｅｘの繊維で構成され、液透過層５は繊度が４．４ｄｔｅｘの繊維で構成されている。液透過層５の密度は表面シート３よりも低く、液透過層５が繊度の大きい繊維で形成されているため、液透過層５はクッション性を発揮できる。よって縦方向中心線Ｏｙ−Ｏｙを中心とする一定の幅の範囲に前記液透過層５を設けることにより、この一定の範囲が身体に与える接触感触を軟質にできる。
【００５０】
前記液獲得層６は、液の吸収機能と透過機能および形状保持性を有する吸水性シート８により、図４に示すように立体的に賦形されたものである。この実施の形態では吸水性シート８は、セルロース系繊維と合成樹脂繊維を含む。この実施の形態では、セルロース系繊維として化学パルプが使用され、合成樹脂繊維として芯部がポリエチレンテレフタレート（ＰＥＴ）で鞘部がポリエチレン（ＰＥ）の芯鞘型複合合成繊維が使用されたエアレイド不織布（エアレイドパルプ）である。このエアレイド不織布は、前記繊維が空間中で積層されてウエッブが形成され、エチレン酢酸共重合体のエマルジョンなどのバインダーが不織布全体の５〜２０質量％の範囲で含まれてシート状とされたものである。
【００５１】
液獲得層６が、経血を吸収して液吸収層４に向けて透過させるために、前記吸水性シート８には、繊維の合計に対して前記化学パルプが２０質量％以上含まれていることが好ましい。また図４に示す立体形状を経血を含んだ湿潤状態でも維持できるようにするためには、前記合成樹脂繊維も２０質量％以上含まれていることが好ましい。すなわち、吸水性シートを形成する化学パルプと合成樹脂繊維の質量比の好ましい範囲は、８０：２０〜２０：８０である。
【００５２】
液獲得層６を図４に示す立体状態に維持できるために、吸水性シート８の目付けは２０〜２００ｇ／ｍ２であることが好ましい。この目付けを維持するために吸水性シート８は、エアーレイド不織布が１枚で使用されてもよいし、あるいは折り畳んで２枚あるいは３枚重ねで使用されてもよい。
【００５３】
図４の立体形状とされた液獲得層６の乾燥時の引張り破断強度は、Ｘ方向とＹ方向の双方において幅２５ｍｍあたり２．５Ｎ以上であることが好ましい。この引っ張り破断強度は、幅２５ｍｍでＸ方向およびＹ方向に細長とされた液獲得層６の試験片のそれぞれを、１００ｍｍのチャック間距離で保持し、前記チャック間を１００ｍｍ／ｍｉｎで広げたときに測定される最大荷重である。なお、前記液獲得層６に後に説明する人工経血を吸収させた湿潤状態での引張り破断強度は、前記乾燥時の強度の２０％以上であることが好ましく、３０％以上であることがさらに好ましい。
【００５４】
前記、目付けおよび引張り強度を有するものであれば、液獲得層６は乾燥時および経血を吸収した湿潤時において、立体形状を維持しやすくなり、液獲得層６の凹部によって繰り返し与えられる経血を保持する機能を発揮できる。前記目付けおよび引っ張り破断強度を有するものであれば、液獲得層６は前記エアーレイド不織布以外のものであってもよい。
【００５５】
例えば、パルプのみをバインダーで接合したエアーレイド不織布であってもよい。あるいは、セルロース系繊維と合成樹脂繊維をウォータジェットで交絡させたスパンレース不織布であってもよい。または、セルロース系繊維であるパルプとレーヨンの少なくとも一方を主体とするスパンレース不織布と、合成樹脂繊維を主体とするエアースルー不織布とをウォータジェット処理や熱シールで一体化したものであってもよい。または前記スパンレース不織布とポイントボンド不織布、あるいは前記スパンレース不織布とスパンボンド不織布を同様にして一体化したものや、セルロース系繊維を主体としたスパンレース不織布と多数の開孔を有するフィルムとが接合されたものであってもよい。
【００５６】
また、液獲得層６を多種の繊維で形成する場合に、セルロース系繊維の含有率が、液透過層５に向く側で液吸収層４に向く側よりも高くなったものを使用すると、液透過層５から液獲得層６へ経血を引き込みやすくなる。逆に液吸収層４に向く側でセルロース系繊維の含有率を高くすると、液吸収層４へ経血を移行させやすくなる。
【００５７】
図４に示すように、液獲得層６は、表面シート３に凸側が向くように変形した縦リブ６ａと、同じく表面シート３に凸側が向くように変形した横リブ６ｂが形成されている。縦リブ６ａは縦方向（Ｙ方向）に直線的に延びて横方向に等間隔に位置して互いに平行に形成されている。横リブ６ｂは、隣り合う縦リブ６ａ，６ａを連結するように形成されている。横リブ６ｂは縦方向に一定の間隔を空けて平行に形成されているが、横方向に隣り合う横リブ６ｂは同一線上に位置しておらず、縦方向に並ぶ横リブ６ｂと、その隣で縦方向に並ぶ横リブ６ｂとが互い違いに位置するように配置されている。
【００５８】
前記縦リブ６ａと横リブ６ｂとで囲まれた部分に液吸収層４に向けて窪む凹部６ｃが形成されており、この凹部６ｃはＸ方向の幅寸法よりもＹ方向の長さ寸法の大きい縦長形状である。液獲得層６は多数の前記凹部６ｃが規則的に配列されたものである。
【００５９】
液獲得層６は、両側縁部６ｈ，６ｈから内側へ一定の幅寸法Ｗａの範囲が平坦部６ｆ，６ｆとなっており、この平坦部６ｆ，６ｆには前記凹部６ｃが形成されていない。この平坦部６ｆ，６ｆは、縦リブ６ａの後に説明する幅寸法よりも広く、平坦部６ｆの幅寸法Ｗａは縦リブ６ａの幅寸法の１．２〜１０倍以上であり、さらに好ましくは２〜５倍である。この実施の形態では、液獲得層６の両側部に平坦部６ｆ，６ｆが形成され、平坦部６ｆと平坦部６ｆとで挟まれた全領域に前記凹部６ｃが規則的に配列している。ただし、液獲得層６の前縁部６ｉおよび後縁部６ｊから内側への所定範囲が平坦部であってもよい。この場合、前縁部６ｉと後縁部６ｊからの平坦部の幅寸法は、横リブ６ｂの幅寸法の１．２〜１０倍以上であり、さらに好ましくは２〜５倍である。
【００６０】
図６に示すように、凹部６ｃの下面から縦リブ６ａの頂部までの高さ寸法ｈ１は、前記下面から横リブ６ｂの頂部までの高さ寸法ｈ２よりも高い。そして、図３に示すように、前記縦リブ６ａの頂部が、前記液透過層５の下面に接してホットメルト接着剤により接着されており、前記凹部６ｃの下面が、ホットメルト接着剤により液吸収層４の上面に接着されている。すなわち、それぞれの縦リブ６ａの頂部は同一平面上に位置して、それぞれの縦リブ６ａの頂部が液透過層５に接しており、それぞれの凹部６ｃの下面が同一平面上に位置しており、それぞれの凹部６ｃの下面が液吸収層４に接している。また、液獲得層６の前記平坦部６ｆ，６ｆも液透過層５の下面にホットメルト接着剤により接着されている。
【００６１】
前記ホットメルト接着剤は、液獲得層６の下面（着衣側に向く表面）と、液吸収層４の表面（肌側に向く表面）の一部にランダムに塗工されており、液透過層５から液獲得層６への経血の浸透と、液獲得層６から液吸収層４への経血の浸透が、前記ホットメルト接着剤により阻害されないようになっている。
【００６２】
前記のように、横リブ６ｂの頂部は、縦リブ６ａの頂部よりも低いため、多数存在している横リブ６ｂの少なくとも一部のものは、その頂部が液透過層５に接着されておらず、その横リブ６ｂの頂部と液透過層５との間には微小な隙間が形成されている。
【００６３】
後に説明するように、前記液獲得層６は、平坦な吸水性シート８を型ロールで挟んで立体形状に賦形したものである。この立体形状への賦形の際に、凹部６ｃの壁部６ｅに引っ張り応力が集中するために、この壁部６ｅでは繊維どうしを離す力が作用し、この壁部６ｅに、縦リブ６ａの頂部と横リブ６ｂの頂部および凹部６ｃの底部６ｄよりも繊維密度が低い部分が存在する。また前記壁部６ｅに、前記応力の集中により亀裂が生じる部分も存在している。ただし、縦リブ６ａの頂部と凹部６ｃの底部６ｄでは、吸水性シート８を形成している繊維が加圧されて、この部分では繊維密度が高くなっている。また、平坦部６ｆには成形時の圧力が作用しないため、平坦部６ｆは、縦リブ６ａの頂部および凹部６ｃの底部６ｄよりも密度が低くなっている。
【００６４】
また、液獲得層６の平均密度は、表面シート３および液透過層５よりも高くなっており、液獲得層６の平均密度よりもその下の液吸収層４の繊維密度が高くなっている。液獲得層６の縦リブ６ａが液透過層５に接し、凹部６ｃの底部６ｄが液吸収層４に接しているため、前記密度勾配により、経血は表面シート３から液透過層５を経て液獲得層６へ移行しやすく、さらに液獲得層６から液吸収層４へ移行しやすい。また、前記のように、液獲得層６の凹部６ｃの壁部６ｅに繊維が離れて密度が低くなった部分、さらには亀裂が存在しているため、前記凹部６ｃに一時的に留められた経血は、速やかに液吸収層４に移行できるようになる。
【００６５】
経血が、液案内層５から液獲得層６へ速やかに移行し、また液獲得層６から液吸収層４に迅速に与えられるようにするために、液獲得層６の平均密度は、０．０５〜０．２５ｇ／ｃｍ３が好ましく、この液獲得層６の下に位置する液吸収層４の繊維密度は、０．０７〜０．２５ｇ／ｃｍ３が好ましい。
【００６６】
前記縦リブ６ａの（１／２）・ｈ１の高さ位置での幅寸法、および横リブ６ｂの（１／２）・ｈ２の高さ位置での幅寸法は２〜１０ｍｍであり、好ましくは２〜６ｍｍである。また液獲得層６の高さｈ１は、１．３〜５ｍｍである。表面シート３を透過した経血を凹部６ｃで充分に溜めることができるためには、１つの前記凹部６ｃの（１／２）・ｈ２の高さ位置での開口面積は５〜２０ｍｍ２であることが好ましく、また凹部６ｃの空間容積｛前記面積×（高さｈ１−吸水性シートの厚み）｝は、８〜８０ｍｍ３であることが好ましい。
【００６７】
また１つの凹部６ｃの（１／２）・ｈ２の高さ位置での開口寸法の縦横比、すなわち（Ｙ方向の縦寸法）／（Ｘ方向の横幅寸法）は、１．１〜１０の範囲が好ましく、さらに好ましくは１．５〜７、最も好ましくは２〜５である。縦横比が前記範囲未満であると、液獲得層６で獲得した経血を縦方向へ案内する機能が低下して、横方向へ拡散が増大するおそれが生じ、縦横比が前記範囲を越えると、横リブ６ｂどうしの間隔が広くなりすぎて、大腿部などから横方向に向く圧縮力を受けたときに、横方向へ広がろうとする弾性復元力が低下する。
【００６８】
この液獲得層６は、横リブ６ｂが縦方向へ間隔を空けて形成されているため、生理用ナプキン１に対して、前縁部１ｃと後縁部１ｄとが接近する方向で且つ肌側表面が凹となるように湾曲する力が作用したときに、液獲得層６はこの変形に追従して湾曲しやすくなる。特に凹部６ｃの縦横比が前記範囲内であると、液獲得層６が前記方向へ湾曲しやすくなる。生理用ナプキン１の湾曲変形に液獲得層６が追従することにより、液獲得層６と液透過層５との界面の剥離が生じにくくなる。
【００６９】
図４に示すように、横リブ６ｂは横方向（Ｘ方向）に向けて互い違いに配置されているため、液獲得層６が前記のように縦方向に向けて湾曲しやすくなる。さらに、横リブ６ｂの高さｈ２が縦リブｈ１よりも低いために、液獲得層６は側縁部６ｈと６ｈが互いに接近ししかも肌側に向く面が凹状となる方向へも変形しやすくなる。
【００７０】
前記液吸収層４は、粉砕パルプ、マーセル化パルプ、クロスリンクパルプなどのパルプの集合体に、ポリアクリル酸塩、ポリアクリルアミド、無水マレイン酸塩などの合成吸水ポリマーや、デンプン、セルロースなどの天然系の吸収ポリマーが含まれているものであり、パルプおよび前記合成吸水ポリマーなどが、親水性のティシューペーパで包まれたものが使用される。
【００７１】
前記裏面シート２は、液不透過性で且つ通気性のシートであり、微細な通気孔が形成されたポリエチレン（ＰＥ）フィルム、あるいはポリプロピレン（ＰＰ）フィルムなどである。例えば、プラスチックシートにＣａＣＯ３、ＢａＳＯ４等の無機フィラーを混合させて延伸処理することにより、微細な通気孔が適切に分散して形成され、通気性を向上させた、厚みが１５〜５０μｍ程度のフィルムを形成できる。
【００７２】
図２に示すように、肌側表面の左右両側には不透液性シート３０が設けられており、前記ウイング部１Ａ，１Ａでは、前記不透液性シート３０，３０が、裏面シート２の上にホットメルト接着剤で接着されている。縦方向中心線Ｏｙ−Ｏｙから左右に等距離離れた位置で、不透液性シート３０が２枚重ねに折り畳まれ、その内部に縦方向に延びる弾性部材３２が接着されている。前記弾性部材３２により、生理用ナプキン１の前方部分と後方部分との間に弾性収縮力が作用して生理用ナプキン１を湾曲させる力が作用し、その結果生理用ナプキン１の前後の中間部分で、不透液性シート３０，３０が立ち上がって防漏壁３１，３１が形成される。
【００７３】
前記不透液性シートは、スパンボンド不織布、メルトブローン不織布、あるいはこれらを積層した複合不織布で形成されている。
【００７４】
液吸収層４の目付けは、中央領域２０において最も大きく、内側圧縮溝１１，１１と外側圧縮溝１６，１６とで挟まれた部分の目付けは、前記中央領域２０よりも小さい。それ以外の部分の液吸収層４の目付けは、内側圧縮溝１１，１１と外側圧縮溝１６，１６とで挟まれた部分と同等かあるいは少し小さくなっている。
【００７５】
中央領域２０での液吸収層４の好ましい目付けは、４００〜１２００ｇ／ｍ２であり、さらに好ましくは、５００〜１０００ｇ／ｍ２である。前記内側圧縮溝１１，１１と外側圧縮溝１６，１６とで挟まれた部分の好ましい目付けは、３００〜９００ｇ／ｍ２であり、さらに好ましくは３５０〜６００ｇ／ｍ２である。またその他の部分の液吸収層４の好ましい目付けは、２００〜７００ｇ／ｍ２であり、さらに好ましくは３００〜５００ｇ／ｍ２である。
【００７６】
その結果、図２に示すように中央領域２０で厚みが大きくなり、中央領域２０では、肌側表面が身体に向けて大きく膨らんだ形状となる。
【００７７】
中央領域２０の縦方向の寸法、すなわち前方連結圧縮溝１２と後方連結圧縮溝１３との縦方向の間隔は、５０ｍｍ以上である。図２に示す横方向基準線Ｏｘ−Ｏｘ上での中央領域２０の幅寸法Ｗ１は、女性の性器の幅に応じて決められる。女性の股間部の幅の平均は３０ｍｍ程度であるため、前記幅寸法Ｗ１は、１５〜５０ｍｍの範囲が好ましく、さらに２０〜４０ｍｍの範囲が好ましい。
【００７８】
この生理用ナプキン１を身体に装着するときには、裏面シート２の外面に設けられた感圧接着剤を、図２に示すクロッチ布２６の内面に接着し、ウイング部１Ａ，１Ａを、クロッチ布２６の両側縁部を巻き込むようにして、下着の外面に向けて曲げ、ウイング部１Ａ，１Ａの着衣側表面に設けられた感圧接着剤をクロッチ布２６の外面に接着する。
【００７９】
図２に示すように、この生理用ナプキン１は、中央領域２０が身体に向けて膨らんでいるため、この中央領域２０が膣口に密着しやすくなっている。前記中央領域２０の肌側表面に位置する表面シート３は低密度のエアースルー不織布であり、その下には嵩高のエアースルー不織布の液透過層５が設けられている。そのため、中央領域２０が身体の前記各部分に与える接触感触が軟質である。
【００８０】
膣口から排泄された経血は、主に中央領域２０に与えられる。表面シート３は低密度の不織布であるため、経血は表面シート３内に浸透するが、表面シート３に撥水性油剤をコーティングした繊維が含まれているため、表面シート３での経血の拡散は抑制される。表面シート３の下に位置する液透過層５はエアースルー不織布で内部に空隙を有しているため、経血は重力によって液透過層５の空隙内を通過し、その下に位置する液獲得層６に落下する。ただし、中央領域２０に与えられた経血の多くは、液透過孔２５内を速やかに通過して、直接に液獲得層６に向けて落下する。
【００８１】
液獲得層６は、吸水性シート８で形成されているため、液獲得層６に落下した経血は吸水性シート８で吸収され、さらにその下に位置する液吸収層４に与えられる。表面シート３に一時に多くの経血が与えられると、この経血が液透過孔２５を透過して液獲得層６に落下するが、この経血は液獲得層６の凹部６ｃ内に直ちに蓄えられるため、経血の排泄量が多くても、これが表面シート３や液透過層５に長い時間滞留することがない。よって中央領域２０の肌側表面が乾燥に近い状態を保てるようになり、装着者の股間部に湿潤感や蒸れ感を与えにくくなっている。
【００８２】
液獲得層６の凹部６ｃに与えられた経血は凹部６ｃの底部６ｄから液吸収層４に浸透し、また凹部６ｃの壁部６ｅでの密度の低い部分や亀裂を透過して液吸収層４に速やかに吸収される。また、多くの経血が凹部６ｃに与えられ、いずれかの凹部６ｃにおいて、その空間容積よりも経血の量が多くなった場合、この経血は低い高さの横リブ６ｂを越えて縦方向に隣接する凹部６ｃに移行していく。一方、凹部６ｃの両側に位置する縦リブ６ａは縦方向に平行に延びてその頂部が液透過層５に接触して接着されているために、液獲得層６において経血が横方向に拡散しにくくなっている。よって多量の経血が与えられたときに、この経血は縦方向に並ぶ凹部６ｃに順次移行しながら液吸収層４で吸収されていくようになる。
【００８３】
さらに、前記液獲得層６の左右両側部には、縦方向に延びる平坦部６ｆ，６ｆが形成されている。この平坦部６ｆ，６ｆは縦リブ６ａよりも繊維密度が低いため、液獲得層６を横方向（Ｘ方向）へ伝わる経血が存在しても、前記平坦部６ｆ，６ｆが横方向へ拡散する経血を止める機能を発揮できる。よって、横方向への洩れの不安を低減できる。
【００８４】
また、液獲得層６の両側縁部６ｈ，６ｈからさらに横方向へ経血が移行したときに、この経血は、両側に位置する内側圧縮溝１１，１１により留められ、さらにその外側に位置する外側圧縮溝１６，１６によっても留められるため、生理用ナプキン１からの横方向への液漏れを効果的に抑止できる。
【００８５】
液獲得層６を形成する吸水性シート８は合成樹脂繊維を含んでいるため、経血を吸収した湿潤状態においても立体的な形状を保てるようになり、股間部からの圧力が中央領域２０に作用しても、その圧力が除去されたときに、図４に示す立体形状に復元できるようになる。特に、縦リブ６ａと横リブ６ｂが設けられているため、液獲得層６は弾性復元機能が優れている。
【００８６】
次に、前記生理用ナプキン１の製造方法を説明する。
まず、液獲得層６を図４に示す立体形状に賦形する工程を説明する。
【００８７】
図７は、液獲得層６を形成するための上型４０を示す斜視図であり、図８は下型５０を示す斜視図である。図９は前記上型４０のＩＸ−ＩＸ線での断面図である。
【００８８】
図７に示す上型４０には、複数の凸部４１と、隣接する前記凸部４１と凸部４１との間に位置する溝部４２とが、共に縦方向（Ｙ方向）に延びて互いに平行に形成されている。前記凸部４１には、縦方向（Ｙ方向）に間隔を開けて凹部４３が形成されている。いずれかの凸部４１に形成されている凹部４３は、隣接する凸部４１に形成された凹部４３と凹部４３との中間に位置している。すなわち隣接する凸部４１と凸部４１との間では、前記凹部４３が互い違いに配列されている。
【００８９】
図９に示すように、凸部４１と凹部４３との境界部では、凸部４１の端部４１ａが円弧曲線を描いて凹部４３に連続している。図９に示すように、前記溝部４２の底面４２ａから前記凸部４１の頂部までの高さ寸法Ｈ１は、前記底面４２ａから前記凹部４３の頂部までの高さ寸法Ｈ２よりも高くなっている。
【００９０】
図８に示す下型５０は、縦方向（Ｙ方向）に延びる凸条部５１が互いに平行に形成されており、隣接する前記凸条部５１，５１の間に溝部５２が形成されている。上型４０の隣接する凸部４１のピッチと、下型５０の隣接する溝部５２のピッチは同一である。
【００９１】
前記上型４０の表面と下型５０の表面とが、芯鞘型合成繊維の鞘部のポリエチレンの融点よりも低い１２０℃程度に加熱された状態で、図１０に示すように、上型４０と下型５０との間に吸水性シート８が挟まれる。上型４０と下型５０は、凸部４１が溝部５２に入り込み、凸条部５１が溝部４２に入り込むように組み合わされる。ただし、上型４０の凸部４１の頂部と下型５０の溝部５２の底面との間に若干のクリアランスが保たれ、下型５０の凸条部５１の頂部と、上型４０の溝部４２の底面との間に若干のクリアランスが保てるように、上型４０と下型５０は互いに加圧されないように組み合わされる。
【００９２】
その結果、図１０（Ａ）に示すように、下型５０の凸条部５１によって縦リブ６ａが形成され、上型４０の凸部４１によって凹部６ｃが形成される。また上型４０の凹部４３によって吸水性シート８が軽く加圧されて、この凹部４３によって前記横リブ６ｂが形成される。
【００９３】
なお、上型４０の両側部には縦方向に延びる平面４４，４４が形成され、下型５０の両側部にも縦方向に延びる平面５３，５３が形成されている。そして、この平面４４，４４と平面５３，５３とで挟まれた部分では、吸水性シート８が加圧されず、前記平坦部６ｆ，６ｆが形成される。
【００９４】
上型４０と下型５０が、複合合成繊維の融点よりもやや低い温度に加熱されて、且つ上型４０と下型５０とがクリアランスを保った状態で、吸水性シート８が挟み込まれる。前記温度で且つ型どうしがクリアランスを有するように噛み合わされて吸水性シート８が成型されるため、液獲得層６では繊維が溶融してフィルム状となる部分が存在せず、液の透過機能を妨げることがない。また複合合成繊維が軟化する程度の温度で加熱されることにより、成型後に図４に示す立体形状を保てるようになる。
【００９５】
液獲得層６の凹部６ｃは、縦方向の寸法が短く区切られている凸部４１によって加圧されて形成されるため、凹部６ｃの壁部６ｅとなるシートにＸ方向とＹ方向の双方の引張り応力が集中する。よって、凹部６ｃの壁部６ｅを形成している繊維の間隔が広げられ、さらに場所によっては亀裂が発生する。このとき、縦方向に連続している凸条部５１によって縦リブ６ａを加圧して形成することで、縦リブ６ａの頂部では繊維密度を高くすることもでき、同様に凹部６ｃの底部６ｄの繊維密度も高くすることができる。また横リブ６ｂの頂部の繊維密度も、前記壁部６ｅよりも高くなる。
【００９６】
なお、液獲得層６を量産するときには、図７に示す上型４０は、Ｙ方向が周方向でＸ方向が軸方向となるようにロール表面に形成され、図８に示す下型５０も、Ｙ方向が周方向でＸ方向が軸方向となるようにロール表面に形成され、両ロールがクリアランスを有して対向し、その間に吸水性シート８が供給されて液獲得層６が形成される。
【００９７】
生理用ナプキン１の製造工程は、表面シート３と液透過層５を重ねて、前記液透過孔２５を形成する。次に、液透過層５の裏に液獲得層６の縦リブ６ａおよび平坦部６ｆ，６ｆをホットメルト接着剤で接着する。さらに液獲得層の凹部６ｃの下面を液吸収層４にホットメルト接着剤で接着する。表面シート３、液透過層５、液獲得層６および液吸収層４を重ねた状態で、圧縮溝１０を形成する。その後に、液吸収層４の着衣側表面に裏面シート２を重ねて接着し、肌側表面には、前記不透液性シート３０を接着する。
【００９８】
なお、液獲得層６の両側部には縦方向に延びる平坦部６ｆ，６ｆが形成されており、この平坦部６ｆ，６ｆは、凹部６ｃの壁部６ｅのように繊維間が広げられておらず、ある程度の剛性を有し、しかも密度が均一である。よって、生理用ナプキン１の組立工程では、例えばサクションベルトに前記平坦部６ｆ，６ｆを吸引して液獲得層６を搬送することが可能であり、このサクションベルトにより、液獲得層６をその立体形状を維持したまま供給することができる。
【００９９】
前記液獲得層６は、１枚の吸水性シート８で形成することもできるが、複数枚の吸水性シート８を重ねて形成することもできる。図５（Ｂ）は２枚の吸水性シート８Ａと８Ｂを重ねて液獲得層６を形成した例を示している。２枚の吸水性シート８Ａと８Ｂのそれぞれは、前記吸水性シート８と同じ素材で形成されている。
【０１００】
液獲得層６を立体形状とする際に、凹部６ｃの壁部６ｅに張力が作用して繊維の間隔が広げられ、場所によっては亀裂が形成される。ただし、複数枚の吸水性シートを重ねて用いていると、前記壁部６ｅにおいて複数の吸水性シートのそれぞれにおいて繊維密度が低くなる部分や亀裂が生じる部分が異なるようになって一箇所に集中することがなくなる。よって、凹部６ｃの壁部６ｅの全体の強度の低下を防止でき、体圧が作用し、平坦な状態に潰された後に、立体形状への復元性を高くできる。
【０１０１】
また、複数枚の吸水性シートが部分的に接着されたものを使用することができる。複数枚の吸水性シートが熱可塑性繊維を含んでいる場合には、繊維どうしの融着により吸水性シートどうしを接着することができる。あるいは、吸水性シートを接着剤で接着してもよい。図７ないし図１０に示すように、加熱した型を用いて液獲得層６を立体形状にするときに、型の熱により吸収性シートをフィルム状とならない程度の圧力で接着することができる。または、複数の吸水性シートを予めドット状の接着部で熱接着しておき、この熱接着された吸収性シートの積層体によって、液獲得層６を立体形状に賦形してもよい。
【０１０２】
複数枚の吸収性シートを接合する際に、その接合箇所は、縦リブ６ａ、横リブ６ｂ、凹部６ｃの壁部６ｅ、凹部の底部６ｄのいずれかであればよい。あるいは接合箇所が、前記全ての部分にランダムに形成されていてもよい。ただし、少なくとも凹部６ｃの壁部６ｅにおいて液吸収シートどうしが接合されていることが好ましい。
【０１０３】
縦リブ６ａと横リブ６ｂの部分に吸水性シートどうしの接着部が設けられていると、縦リブ６ａと横リブ６ｂの骨格構造を強くできる。また前記のように凹部６ｃの壁部６ｅでは、繊維密度が極端に低くなっているため、この部分で吸水性シートの接着部が設けられていると、凹部６ｃの剛性を高めて、凹部６ｃの形状を維持しやすくなる。また、凹部６ｃの底部６ｄに接着部が設けられている場合には、この部分の密度を高くでき、その結果、液獲得層６に与えられた経血を凹部６ｃの底部６ｄに集中させて液吸収層４に与えることが可能となる。
【０１０４】
図１１は本発明の吸収性物品の第２の実施の形態の生理用ナプキン１００を示す平面図である。なお、図１に示す実施の形態と同じ構造の部分は同じ符号を付して詳しい説明を省略する。
【０１０５】
この生理用ナプキン１００は、就寝中などに使用するのに適したロングタイプであり、縦方向（Ｙ方向）の全長寸法は、ほぼ２００〜４５０ｍｍであり、両側縁部１ａ，１ｂは、横方向基準線Ｏｘ−Ｏｘから後縁部１ｄへ向かうにしたがって徐々に広くなるように膨らんだ形状となり、臀部に当たる後方フラップ１Ｂ，１Ｂが形成されている。
【０１０６】
肌側表面には、内側圧縮溝１１，１１が縦長に形成されている。内側圧縮部１１，１１の前方部分１１Ａ，１１Ａは、縦方向中心線Ｏｙ−Ｏｙに向けて凸状の円弧曲線パターンである。また内側圧縮溝１１，１１には、前記前方部分１１Ａ，１１Ａの後方で対向間隔が広がる変曲部１１Ｂ，１１Ｂが形成されており、さらに後方部分１１Ｄ，１１Ｄは、後縁部１ｄに向かうにしたがって徐々に狭くなり、後方連結圧縮溝１３Ａにより互いに連結されている。
【０１０７】
内側圧縮溝１１，１１、前方連結圧縮溝１２および後方連結溝１３Ａで囲まれた部分が中央領域２０である。中央領域２０は、前記前方部分１１Ａ，１１Ａで挟まれた部分が、主に女性の膣口に対向する前方中央領域２０Ａであり、変曲部１１Ｂ，１１Ｂで挟まれた部分が、主に女性の会陰部に対向する中間中央領域２０Ｂであり、後方部分１１Ｄ，１１Ｄで挟まれた部分が、主に肛門と臀部の溝に対向する後方中央領域２０Ｄである。
【０１０８】
また、内側圧縮溝１１，１１の前方部分１１Ａ，１１Ａの左右両外側には、図１と同様の外側圧縮溝１６，１６が形成され、内側圧縮溝１１，１１の後方部分１１Ｄ，１１Ｄの左右外側には後方外側圧縮溝１７，１７が形成され、この後方外側圧縮溝１７，１７は後縁部１ｄの内側で互いに連結されている。
【０１０９】
この実施の形態では、液透過層５が前縁部１ｃから後縁部１ｄにかけて帯状に形成されて設けられ、また前記中央領域２０には、図４に示したのと同じ立体形状の液獲得層６が設けられている。
【０１１０】
中央領域２０は、前方連結圧縮溝１２から後方連結圧縮溝１３Ａまでの縦方向の長さが１２０〜３５０ｍｍの長い範囲に形成されているが、前記液獲得層６は、少なくとも膣口に対向する部分である前方中央領域２０Ａに設けられる。または図１１に示すように、前記液獲得層６が前方中央領域２０Ａと、会陰部に対向する中間中央領域２０Ｂにかけて設けられていてもよい。
【０１１１】
【実施例】
以下の各層を形成する
（ａ）表面シート３
酸化チタンを繊維質量の１．１％の割合で含んだポリエチレンテレフタレートが芯部、ポリエチレンが鞘部の芯鞘型複合合成繊維（２．２ｄｔｅｘ、繊維長４４ｍｍ）で形成したエアースルー不織布で、目付けが２５ｇ／ｍ２のものを用いた。
【０１１２】
以下の測定では幅が１３０ｍｍで、長さが２００ｍｍで重さが０．６３７ｇのものを用いた。
【０１１３】
（ｂ）液透過層５
芯部がポリプロピレンで鞘部がポリエチレンの断面が偏芯形状の芯鞘型複合合成繊維（４．４ｄｔｅｘ、繊維長５０ｍｍ）のエアースルー不織布（目付け２０ｇ／ｍ２）で、平均厚みが１．７５ｍｍで平均密度が０．０１７５ｇ／ｃｍ３のものを３枚重ねに折り畳んだものを用いた。
【０１１４】
以下の測定では幅が１００ｍｍで、長さが２００ｍｍで重さが０．４１５ｇのものを用いた。
【０１１５】
（ｃ）液透過孔２５
前記表面シート３と液透過層５を重ね、１００℃のピンを有するロールと、前記ピンが入る穴を有する７０℃のロールとで、表面シート３から液透過層５を貫通する液透過孔２５を形成した。液透過孔２５の開口直径は２ｍｍ、ピッチはＹ方向に５．５ｍｍ、Ｘ方向に３．５ｍｍの配列とした。
【０１１６】
（ｄ）液獲得層６
化学パルプを６０質量％、芯部がポリエチレンテレフタレートで鞘部がポリエチレンの芯鞘型複合合成繊維（１．７ｄｔｅｘ、繊維長１３ｍｍ）を２６質量％、エチレン酢酸ビニル共重合体のエマルジョン接着剤を１４質量％含むエアレイド不織布（エアレイドパルプ）で、目付けが４０ｇ／ｍ２のものを２枚重ねに折り畳んだものを吸水性シート８として使用した。
【０１１７】
以下の測定では幅が５０ｍｍで、長さが１００ｍｍで重さが０．２０５ｇのものを用いた。
【０１１８】
表１の比較例１は、前記吸水性シート８を立体に変形させることなく、そのまま液獲得層６として使用した。乾燥状態の前記吸水性シート８の５回測定の平均厚みは０．９２８ｍｍであった。
【０１１９】
立体に成型する前の前記吸水性シート８の平均密度は０．０７５ｇ／ｃｍ３で、液獲得層６が立体形状とされた後に測定したＹ方向とＸ方向の乾燥時の引張り破断強度は、それぞれ３．４６Ｎ／２５ｍｍ、および２．８３Ｎ／２５ｍｍ、であった。
【０１２０】
前記吸水性シート８を立体成型して液獲得層６を得た。縦リブ６ａのｈ１／２の高さでの幅寸法を３ｍｍ、横リブ６ｂのｈ２／２の高さでの幅寸法を２．５ｍｍ、ｈ２／２の高さ位置での凹部６ｃの開口面積を１５ｍｍ２とした。
【０１２１】
ただし、表１に示す比較例２、実施例１〜実施例８のそれぞれにおいて、前記上型４０と下型５０の対向クリアランスを変化させて、乾燥状態での液獲得層６の厚み（図６のｈ１）を変化させた。
【０１２２】
比較例２は、前記厚みが１．１９２ｍｍであるため、凹部６ｃの空間容積は、｛１５×（１．１９２−０．９２８）｝＝３．９６ｍｍ３、同様に計算すると、実施例の中で最も厚みの小さい実施例２は、８．６１ｍｍ３、最も厚みの大きい実施例８は、３２．６４ｍｍ３である。すなわち実施例での凹部の空間容積は８．６１から３２．６４ｍｍ３であった。
【０１２３】
（ｅ）液吸収層４
化学パルプ８ｇ、吸水性ポリマー０．１５ｇを均一に混合させて、幅７０ｍｍ、長さ２００ｍｍで密度０．０６９ｇ／ｃｍ３の積層体を１５ｇ／ｍ２のティッシュペーパで包んだものを液吸収層４とした。
【０１２４】
（１）厚みの測定
乾燥時と湿潤状態の加圧後に厚みの測定は大栄科学精器製作所社製のＵＦ−６０Ａで測定した。
【０１２５】
（２）ドリップ性試験
表１の比較例１ないし実施例８のそれぞれの液獲得層６を容積が５０ｍｌのビーカーの開口部に固定する。液獲得層６の中央部から上方へ５ｍｍ離したところから、オートビューレットを用いて人工経血を３ｍｌ／ｍｉｎの流量で連続的に落下させる。そして、落下を開始してから、最初にビーカー内に液が落ちるまでの時間を測定した（単位は秒）。
【０１２６】
ここで、人工経血は、４リットルのイオン交換水に、グリセリン３００ｇ、カルボキシメチルセルロースのナトリウム塩を３０ｇ、塩化ナトリウム４０ｇを加えて攪拌し、赤色食紅で着色したものを用いた。
【０１２７】
（３）加圧吸収試験
図１２（Ｂ）に示すように、平坦な試験台６１の上に、液吸収層４、液獲得層６、および液透過層５と表面シート３が一体とされたものを順に重ねる。最上部に図１２（Ａ）に示す寸法のアクリル板６２をその開口部６２ａが中央に一致するように設置する。そして、開口部６２ａの前後にそれぞれ９００ｇの重り６３、６３を乗せる。なお、アクリル板の自重は１１５ｇであった。
【０１２８】
前記人工経血を、オートビューレットを用いて、前記開口部６２ａ内に、９５ｍｌ／ｍｉｎの流量で与える。１回目は３ｍｌを与え、液を供給し始めてから、開口部６２ａにおいて表面シート３の表面に液が無くなるまでの時間（秒）を測定する。１回目に表面シート３の表面に液が無くなってから３０秒経過した後に、２回目として４ｍｌを与えて同様にして浸透時間を測定する。２回目の液が表面シート３の表面から無くなった後に、５分間経過後に、３回目として３ｍｌの液を与え、同様にして浸透時間を測定する。
【０１２９】
３回目に供給した液が表面シート３の表面から無くなった後の、１分経過後に、アクリル板６２と重り６３，６３を外し、それぞれの液獲得層６の厚みを測定する。また、（加圧後の前記厚み／乾燥時の厚み）×１００（％）を厚み変化率として計算した。
測定結果を以下の表１に示す。
【０１３０】
【表１】

Figure 2004181087
【０１３１】
表１から、各実施例では、ドリップ性、加圧吸水性試験での液透過性が良好であることを確認できた。
【０１３２】
なお、前記実施の形態では、表面シート３の下に液案内層５が存在し、その下に液獲得層６が設けられているが、前記表面シート３の下に直接に前記液獲得層６が存在していてもよい。
【０１３３】
【発明の効果】
以上のように本発明では、一時に多量に液が与えられたときに、これを表面シートの下で保持してから、液吸収層に直ちに吸収させることができ、表面シートでの液残りを防止できる。
【図面の簡単な説明】
【図１】本発明の吸収性物品の実施の形態の生理用ナプキンを示す平面図、
【図２】図１に示す生理用ナプキンが下着のクロッチ布に装着された状態を横方向基準線で切断したＩＩ−ＩＩ矢視の断面図、
【図３】液透過孔の開孔状態および液獲得層を示す拡大断面図、
【図４】液獲得層の斜視図、
【図５】図４のＶ−Ｖ線の断面図、
【図６】図４のＶＩ−ＶＩ線の断面図、
【図７】液獲得層を立体とするための上型の斜視図、
【図８】液獲得層を立体とするための下型の斜視図、
【図９】図７のＩＸ−ＩＸ線の断面図、
【図１０】上型と下型で液獲得層を立体成型している状態を示す断面図、
【図１１】本発明の第２の実施の形態の吸収性物品として縦長の生理用ナプキンを示す平面図、
【図１２】（Ａ）は加圧吸収試験に使用するアクリル板の平面図、（Ｂ）は前記加圧吸収試験を説明する断面図、
【符号の説明】
１ 生理用ナプキン
２ 裏面シート
３ 表面シート
４ 液吸収層
５ 液透過層
６ 液獲得層
６ａ 縦リブ
６ｂ 横リブ
６ｃ 凹部
６ｄ 底部
１０ 圧縮溝
１１ 内側圧縮溝
２０ 中央領域
２５ 液透過孔[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an absorbent article suitable for absorbing menstrual blood excreted from female genital organs, and in particular, to obtain a liquid between a topsheet and a liquid absorbing layer to give the liquid to the liquid absorbing layer. The present invention relates to an absorbent article provided with a layer.
[0002]
[Prior art]
The general structure of an absorbent article that absorbs menstrual blood excreted from female genitals is a liquid-permeable top sheet located on the skin side surface, and a liquid impermeable back sheet located on the clothing side surface, It has a liquid absorbing layer interposed between the top sheet and the back sheet, and is usually worn in a state where the back sheet is adhered to the inner surface of an underwear crotch cloth via a pressure-sensitive adhesive layer.
[0003]
In this type of absorbent article, if a large amount of menstrual blood is given to the topsheet at one time, menstrual blood will remain on the topsheet for a long time, giving the crotch a wet feeling and giving the wearer discomfort. become. Therefore, some devices have been devised so that when a large amount of liquid is supplied at one time, the liquid is diffused under the topsheet or held under the topsheet.
[0004]
Patent Literature 1 below discloses a sanitary napkin provided with a liquid transport zone between a topsheet and a liquid absorbing layer.
[0005]
The liquid transport band is formed by forming a large number of concave screen patterns on a nonwoven fabric. This screen pattern is an embossed pattern in which a nonwoven fabric having a predetermined thickness is compressed from one surface to form a high fiber density portion, and an embossed pattern in which the nonwoven fabric is compressed from both surfaces to form a thin film element. The patterns are arranged in the longitudinal direction (longitudinal direction) of the sanitary napkin. The liquid transport zone regulates the movement of menstrual blood that has passed through the topsheet, bypasses the high-fiber-density portion by restricting it with the thin-film element, and thereby diffuses menstrual blood in the vertical direction. It is intended to prevent the liquid remaining at the time.
[0006]
Next, Patent Document 2 discloses a disposable diaper in which a liquid permeable sheet is interposed between a top sheet and a liquid absorbing layer.
[0007]
In the liquid permeable sheet, a nonwoven fabric or paper is three-dimensionally deformed to form a large number of concave portions and mesh-like convex portions that partition the concave portions. This disposable diaper aims to prevent the liquid from flowing along the surface of the diaper by temporarily holding the liquid in the concave portion of the liquid-permeable sheet when a large amount of liquid is given at once. is there.
[0008]
[Patent Document 1]
JP-A-6-38998
[Patent Document 2]
JP 2000-140015 A
[0009]
[Problems to be solved by the invention]
The liquid transport band described in Patent Literature 1 may be able to diffuse the liquid transmitted through the topsheet in the longitudinal direction, but the liquid transport band itself has a low liquid holding ability and a low liquid permeating ability. As soon as a large amount of menstrual blood is given to the liquid transport zone, the fluid transport zone is saturated and easily stays. In other words, this liquid transport zone is formed by forming an embossed pattern on a melt-blown non-woven fabric or the like, but since the melt-blown non-woven fabric is used in a flat state, it itself holds a large amount of locally applied liquid. Not something you can do. Furthermore, since the emboss pattern formed on the nonwoven fabric has a very small space volume in the concave portion, the liquid cannot be substantially retained even in the concave portion of the emboss pattern. On the contrary, the meltblown nonwoven fabric itself has a high density and poor liquid permeability, and furthermore, the liquid permeability is low because the thin film element blocks liquid permeation.
[0010]
Next, the liquid-permeable sheet described in Patent Literature 2 tries to prevent urine from accumulating in the triangular concave portion and to prevent the liquid from diffusing in a planar manner. Therefore, urine is immediately saturated in the recess. Therefore, when the liquid-permeable sheet is applied to a sanitary napkin, if menstrual blood having a higher viscosity than urine concentrates in the concave portion, it tends to stay in the concave portion. Further, in Patent Document 2, as a preferred example of the liquid permeable sheet, the liquid permeable sheet is formed of paper. However, when the liquid permeable sheet formed of such paper is used for a sanitary napkin, The concave portion is immediately crushed by the pressure applied from the portion, and the liquid-permeable sheet is easily broken when a displacement force acts on the sanitary napkin.
[0011]
The present invention solves the above-mentioned conventional problems. When a large amount of liquid is given, the liquid can be temporarily held, and can be smoothly transferred to the liquid absorbing layer. It is an object of the present invention to provide an absorbent article that can reduce the amount of water.
[0012]
[Means for Solving the Problems]
The present invention has a liquid-permeable top sheet located on the skin side surface, a back sheet located on the garment side surface, and a vertically long liquid absorption layer including a liquid absorption layer located between the top sheet and the back sheet. In absorbent articles,
A liquid acquisition layer is provided on the surface of the liquid absorption layer facing the topsheet, and the liquid acquisition layer is one in which the water-absorbent sheet maintains a three-dimensionally deformed state in its thickness direction.
The three-dimensional shape is such that vertical ribs protruding toward the topsheet and extending in the vertical direction are formed in parallel with each other, and horizontal ribs protruding toward the topsheet and extending in the horizontal direction are vertical. Are formed so as to connect the vertical ribs at intervals in the direction, and a number of concave portions surrounded by the vertical ribs and the horizontal ribs are formed to be depressed toward the liquid absorbing layer,
At least the vertical rib is in contact with the topsheet or a liquid permeable layer located below the topsheet, and the bottom of the concave portion is in contact with the liquid absorption layer.
[0013]
In the absorbent article of the present invention, menstrual blood that has passed through the topsheet is temporarily held in the concave portion formed in the liquid acquisition layer, but the liquid acquisition layer is obtained by deforming the water absorbent sheet three-dimensionally. Therefore, the space volume of the concave portion can be increased as compared with the embossed pattern formed on the nonwoven fabric, and a large amount of menstrual blood can be temporarily held in the concave portion. Moreover, since the bottom of the concave portion formed of the water-absorbent sheet is in contact with the liquid absorbing layer, menstrual blood in the concave portion can permeate the water-absorbent sheet and immediately migrate to the liquid absorbing layer, and menstrual blood within the concave portion for a long time. It can prevent accumulation. In addition, since the vertical ribs extend in the vertical direction, which is the longitudinal direction of the article, and the vertical ribs are in contact with the topsheet or the liquid permeable layer, the liquid held in the concave portion is guided in the vertical direction, and is moved in the horizontal direction. Diffusion is easily suppressed. Therefore, menstrual blood can easily penetrate into the liquid absorbing layer without causing lateral leakage.
[0014]
Further, in the present invention, a height from the bottom of the recess to the top of the horizontal rib is lower than a height from the bottom of the recess to the top of the vertical rib.
[0015]
The liquid acquisition layer receives menstrual blood in the concave portion and immediately penetrates the liquid absorbing layer. Even if a large amount of menstrual blood is given to the concave portion at one time, the lateral ribs with low menstrual blood are used. Can be transferred to the concave portions arranged in the vertical direction beyond the vertical direction, so that the diffusion in the horizontal direction can be easily prevented.
[0016]
For this purpose, it is preferable that each of the recesses is vertically long, in which the length in the vertical direction is longer than the width in the horizontal direction.
[0017]
In the present invention, the space volume of one concave portion is 8 to 80 mm. 3 It is preferable that
[0018]
When the space volume of one recess is within the above range, the menstrual blood, which is a highly viscous body fluid, can retain menstrual blood until it passes through the liquid acquisition layer, and many menstrual blood is Even if given for a short period of time, the menstrual blood does not overflow from the recessed portion, preventing the menstrual blood from returning to the topsheet and preventing the menstrual blood from diffusing in the lateral direction.
[0019]
Further, in the present invention, the liquid acquisition layer has a portion where the spacing between the fibers is widened due to the concentration of tensile stress when the water-absorbent sheet is three-dimensionally deformed and the density is reduced.
[0020]
When a portion where the fiber density is low is formed in the liquid acquisition layer, menstrual blood temporarily held in the concave portion can be immediately transferred to the liquid absorption layer.
[0021]
Further, in the present invention, a flat portion having a width larger than the vertical rib is formed continuously in the vertical direction in the liquid acquisition layer.
[0022]
The flat portion is a region that is not subjected to a pulling force or a compressive force when it is formed into a three-dimensional shape, the strength is not reduced, and the fiber density remains the original material, and the density is lower than that of the vertical ribs. Is low. Therefore, when assembling the absorbent article, it is possible to supply the liquid acquisition layer to the assembling process while holding the flat portion. Also, since this flat portion can maintain a lower density than vertical ribs and the like, if this flat portion extends in the vertical direction, this flat portion will serve as a diffusion prevention band to prevent menstrual blood from spreading in the horizontal direction. Can function as This flat portion may be provided at any position of the liquid acquisition layer, but in order to effectively exhibit the function as the diffusion prevention zone, the flat portion is formed on both sides of the liquid acquisition layer. Is preferred. Further, flat portions may be provided at front and rear ends of the liquid acquisition layer.
[0023]
Further, in the present invention, in the liquid acquisition layer, a plurality of the water-absorbent sheets are stacked and the water-absorbent sheets are adhered to each other at least in part, and the plurality of water-absorbent sheets are formed into the three-dimensional shape together. Can be configured as
[0024]
When the liquid acquisition layer is composed of a plurality of water-absorbent sheets, the basis weight can be increased, the ability to absorb and retain the liquid can be increased, and the strength of the vertical ribs and the horizontal ribs can be increased. Furthermore, even if the wall portion of the concave portion has a low density or cracks, if the wall portion is formed of a plurality of sheets, a portion where a low density portion or a crack is formed does not concentrate at one place, Extremely low strength of the wall can be prevented. Therefore, even when the absorbent article is in a wet state, the shape of the concave portion can always be maintained.
[0025]
In the present invention, it is preferable that the breaking strength when the liquid acquisition layer in a dry state is pulled in the vertical direction is 2.5 N or more per 25 mm width.
[0026]
In order to have the strength and exhibit the water absorbing function, it is preferable that the water absorbing sheet is formed of cellulosic fibers and synthetic resin fibers. Further, when the material has the strength, the three-dimensional shape can be easily maintained even when pressure is applied from the body, and the space volume of the concave portion can be maintained for a long time.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
The absorbent article of the present invention is used as a sanitary napkin whose main purpose is to absorb menstrual blood excreted from the vaginal opening of women. Also, of the two surfaces of the absorbent article, the surface facing the crotch portion is referred to as the skin-side surface, and the opposite surface is referred to as the clothes-side surface regardless of whether clothes are worn on the outside.
[0028]
As used herein, the longitudinal centerline means a line extending in the longitudinal direction by bisecting the absorbent article in the lateral direction. On the other hand, in the following first embodiment, the line extending in the horizontal direction that bisects the absorbent article in the vertical direction is used as the horizontal reference line, but this horizontal reference line necessarily bisects the absorbent article in the vertical direction. A longitudinally long absorbent article suitable for women to wear at bedtime, for example as in the second embodiment, which does not mean crossing a position, wherein the wings are located in the front part In this case, when the skin-side surface is worn on the body, the line passing through the center in the vertical direction at the portion corresponding to the vaginal opening is defined as the horizontal reference line.
[0029]
FIG. 1 is a plan view showing a sanitary napkin 1 with a skin side surface facing upward as a first embodiment of the absorbent article of the present invention, and FIG. 2 is a crotch cloth in which the sanitary napkin of FIG. FIG. 3 is a cross-sectional view taken along a line II-II taken along a lateral reference line, showing an attached state, FIG. 3 is an enlarged cross-sectional view showing a central region of the sanitary napkin, and FIG. FIG. 5 is a perspective view, FIG. 5 is a sectional view taken along line VV, and FIG. 6 is a sectional view of FIG. 4 taken along line VI-VI.
[0030]
The sanitary napkin 1 has a right side edge 1a and a left side edge 1b extending in the vertical direction at an equal distance in the horizontal direction from the vertical center line Oy-Oy, and the front and rear sides from the horizontal reference line Ox-Ox. It has a leading edge 1c and a trailing edge 1d in the form of convex curves spaced apart.
[0031]
The right edge portion 1a and the left edge portion 1b protrude to the left and right sides within a predetermined length range in the vertical direction including the horizontal reference line Ox-Ox, and the protruding portions form wing portions 1A, 1A.
[0032]
As shown in the cross-sectional view of FIG. 2, the sanitary napkin 1 has a liquid-impermeable back sheet 2 that appears on the clothing-side surface and a liquid-permeable top sheet 3 that appears on the skin-side surface. A liquid absorbing layer 4 is interposed between the back sheet 2 and the top sheet 3. A liquid permeable layer 5 is provided below the topsheet 3, and a liquid acquisition layer 6 is provided between the liquid permeable layer 5 and the liquid absorbing layer 4.
[0033]
In the sanitary napkin 1, at least the topsheet 3 and the liquid absorbing layer 4 are locally pressurized and heated to form a compression groove 10 that appears on the skin side surface. The compression groove 10 is formed by embossing using a heating roll. In a state where the liquid absorbing layer 4 and the topsheet 3 are superimposed, a flat surface heating roll is applied to the surface of the liquid absorbing layer 4 and a heating roll having an embossed pattern projection is applied to the surface of the topsheet 3. Then, the compressed groove 10 is formed by being pressed and heated.
[0034]
In the compression groove 10, the liquid absorbing layer 4 and the topsheet 3 were pressed into a substantially film-like high-density compressed portion, and the film was not in a film-like shape, but had a higher density than a region other than the compression groove 10. Medium-density compression sections are formed alternately. The compression groove having the high-density compression part and the medium-density compression part is formed as a concave groove that is depressed from the skin side surface of the sanitary napkin 1 to the back sheet 2 side.
[0035]
As shown in FIG. 1, the compression groove 10 is divided into compression grooves 11 to 16.
[0036]
Inner compressed grooves 11, 11 extending in the vertical direction are formed at positions equidistant to the right and left from the vertical center line Oy-Oy. The inner compressed grooves 11 and 11 have an arc curve whose convex side is directed to the vertical center line Oy-Oy so that the opposing interval becomes narrower at the horizontal reference line Ox-Ox. The inner compression groove 11 and the inner compression groove 11 are connected to each other by a front connection compression groove 12 and a rear connection compression groove 13. The front connection compression groove 12 has a curved shape in which the convex side faces the front edge 1c, and the rear connection compression groove 13 has a curved shape in which the convex side faces the rear edge 1d.
[0037]
A pair of front extension compression grooves 14, 14 is formed from the intersection of the inner compression grooves 11, 11 and the front connection compression groove 12 toward the front edge 1c. , And are disposed equidistantly to the left and right with respect to the vertical center line Oy-Oy. Further, a pair of rear extension compression grooves 15, 15 is formed from the intersection of the inner compression grooves 11, 11 and the rear connection compression groove 13 toward the rear edge 1d. The rear extension compression grooves 15, 15 are disposed equidistantly to the left and right with respect to the longitudinal center line Oy-Oy.
[0038]
The inner compression grooves 11, 11, the front connection compression groove 12, the rear connection compression groove 13, the front extension compression grooves 14, 14, and the rear extension compression grooves 15, 15 are all formed continuously. Further, a predetermined range of the skin-side surface of the sanitary napkin 1 is surrounded by the inner compression grooves 11, 11, the front connection compression groove 12, and the rear connection compression groove 13. Has become. The central region 20 has a symmetrical shape with respect to the vertical center line Oy-Oy, and also has a symmetrical shape with respect to the horizontal reference line Ox-Ox.
[0039]
Outer compressed grooves 16, 16 are formed on both left and right outer sides of the inner compressed grooves 11, 11, respectively. The outer compressed grooves 16, 16 are formed in a range of a predetermined length in the longitudinal direction with respect to the horizontal reference line Ox-Ox. The outer compressed grooves 16, 16 have a curved shape similar to the inner compressed grooves 11, 11, and are formed at a constant interval from the inner compressed grooves 11, 11.
[0040]
As shown in FIG. 1, the liquid permeable layer 5 has a strip shape elongated in the vertical direction, and both side edges 5 a, 5 a do not overlap with the left and right inner compressed grooves 11, 11. , 11. The liquid permeable layer 5 extends to the front edge 1 c beyond the front connection compression groove 12 and extends to the rear edge 1 d beyond the rear connection compression groove 13. The topsheet 3, the liquid absorbing layer 5, and the liquid absorbing layer 4 are compressed together at a part of the front connecting compressed groove 12 and the rear connecting compressed groove 13.
[0041]
The liquid acquisition layer 6 is rectangular, and both side edges 6h, 6h are located on the left and right sides beyond the inner compression grooves 11, 11. The front edge portion 6i and the rear edge portion 6j are located closer to the lateral reference line Ox-Ox than the front connection compression groove 12 and the rear connection compression groove 13. In a part of the inner compressed grooves 11, 11, the topsheet 3, the liquid acquisition layer 6, and the liquid absorption layer 4 are compressed together.
[0042]
The central region 20 is provided with a large number of liquid permeation holes 25 arranged regularly. As shown in FIG. 3, the liquid permeable holes 25 are formed so as to penetrate the topsheet 3 and reach the liquid permeable layer 5. Preferably, the liquid permeable holes 25 extend from the topsheet 3 to the liquid permeable layer 5. 25 is formed. Further, in a portion of the liquid permeable layer 5 that deviates from the side edges 5a, 5a, a liquid permeable hole 25 is formed only in the top sheet 3.
[0043]
The opening area of the liquid permeable hole 25 is 0.2 to 8 mm. 2 In this embodiment, the diameter of the circular liquid permeation hole 25 is 0.5 to 3.2 mm. The distance between the centers of the adjacent liquid transmission holes 25 is 1.5 to 8 mm.
[0044]
The topsheet 3 and the liquid permeable layer 5 contain thermoplastic fibers that can be thermally fused. In a state where the topsheet 3 and the liquid permeable layer 5 are overlapped, the needle or the pin is inserted from the topsheet 3 toward the liquid permeable layer 5 side, and is withdrawn, so that the liquid permeable holes 25 are formed. On the inner surface of the liquid permeable hole 5 and around it, the thermoplastic fibers contained in the topsheet 3 and the thermoplastic fibers contained in the liquid permeable layer 5 are fused to each other. Thereby, the opening shape of the liquid permeable hole 25 can be maintained, and the periphery of the liquid permeable hole 25 is reinforced by the liquid permeable layer 5. In addition, since the topsheet 3 and the liquid-permeable layer 5 are joined by the heat fusion, there is no need to bond the topsheet 3 and the liquid-permeable layer 5 with an adhesive, and the liquid permeation is inhibited by the adhesive. Nothing.
[0045]
The topsheet 3 is formed of an air-through nonwoven fabric. This air-through nonwoven fabric is made of a core-sheath type composite synthetic fiber whose core portion is made of polyethylene terephthalate (PET) containing titanium oxide and whose sheath portion is polyethylene (PE), and the fibers are joined by hot air. Is 15-60 g / m 2 It is about. The conjugate synthetic fiber constituting the topsheet 3 is a mixture of a material coated with a hydrophilic oil agent and a material coated with a water-repellent oil agent, and a fiber coated with a water-repellent oil agent. Is 10 to 30% by mass. By uniformly including fibers coated with a water-repellent oil agent on the topsheet 3 so as to have the mixing ratio, it is possible to suppress menstrual blood given to the topsheet 3 from being excessively diffused in the topsheet 3, Menstrual blood mainly passes through the liquid permeation hole 25 and is given to the liquid absorption layer 4.
[0046]
However, the topsheet 3 can transmit menstrual blood toward the liquid permeable layer 5 even in a region other than the liquid permeable holes 25. In order to exhibit such a liquid permeation function, the density of the topsheet 3 is 0.12 g / cm. 3 The lower limit is preferably 0.025 g / cm 3 It is about.
[0047]
The liquid permeable layer 5 is formed of an air-through nonwoven fabric formed of a core-in-sheath type composite synthetic fiber having a core portion of polypropylene (PP) and a sheath portion of polyethylene (PE). The air-through nonwoven fabric of the liquid permeable layer 5 is formed only of fibers coated with a hydrophilic oil agent, and does not include fibers coated with a water-repellent oil agent. In the embodiment shown in FIG. 3, the liquid permeable layer 5 is configured by stacking a plurality of the air-through nonwoven fabrics. For example, one air-through nonwoven fabric is stacked two or three times or four times. The folded one is used. The basis weight of one A-through nonwoven fabric is 15 to 50 g / m 2 And the basis weight of the entire liquid permeable layer 5 is 30 to 150 g / m. 2 Degree, and more preferably 50 to 100 g / m. 2 It is.
[0048]
By making the basis weight of the liquid permeable layer 5 larger than the basis weight of the topsheet 3, it is possible to reinforce the topsheet 3 having a low basis weight and low density. Can be prevented.
[0049]
The fiber density of the liquid permeable layer 5 is lower than the fiber density of the topsheet 3, and the fiber density of the liquid permeable layer 5 is 0.016 to 0.08 g / cm. 3 It is. Further, for example, the topsheet 3 is made of fibers having a fineness of 2.2 dtex, and the liquid permeable layer 5 is made of fibers having a fineness of 4.4 dtex. Since the density of the liquid permeable layer 5 is lower than that of the topsheet 3 and the liquid permeable layer 5 is formed of fibers having a large fineness, the liquid permeable layer 5 can exhibit cushioning properties. Therefore, by providing the liquid permeable layer 5 in a range of a certain width centered on the vertical center line Oy-Oy, the touch feeling given to the body by the certain range can be softened.
[0050]
The liquid acquisition layer 6 is three-dimensionally shaped as shown in FIG. 4 by a water-absorbing sheet 8 having a liquid absorbing function, a liquid transmitting function and a shape retaining property. In this embodiment, the water absorbent sheet 8 contains cellulosic fibers and synthetic resin fibers. In this embodiment, chemical pulp is used as the cellulosic fiber, and an air-laid nonwoven fabric using a core-sheath type composite synthetic fiber whose core is polyethylene terephthalate (PET) and whose sheath is polyethylene (PE) is used as the synthetic resin fiber. (Airlaid pulp). The air-laid nonwoven fabric is a sheet-like material in which the fibers are laminated in a space to form a web, and a binder such as an emulsion of ethylene acetic acid copolymer is contained in the range of 5 to 20% by mass of the entire nonwoven fabric. It is.
[0051]
In order for the liquid acquisition layer 6 to absorb menstrual blood and allow it to permeate toward the liquid absorption layer 4, the water-absorbent sheet 8 contains the chemical pulp in an amount of 20% by mass or more based on the total fiber. Is preferred. In order to maintain the three-dimensional shape shown in FIG. 4 even in a wet state containing menstrual blood, it is preferable that the synthetic resin fiber is also contained in an amount of 20% by mass or more. That is, the preferable range of the mass ratio of the chemical pulp and the synthetic resin fiber forming the water absorbent sheet is 80:20 to 20:80.
[0052]
Since the liquid acquisition layer 6 can be maintained in the three-dimensional state shown in FIG. 4, the basis weight of the water-absorbent sheet 8 is 20 to 200 g / m2. 2 It is preferable that In order to maintain the basis weight, the water-absorbent sheet 8 may be a single air-laid nonwoven fabric, or may be folded and used in two or three layers.
[0053]
It is preferable that the tensile strength at the time of drying of the liquid acquisition layer 6 having the three-dimensional shape in FIG. 4 when dried is 2.5 N or more per 25 mm width in both the X direction and the Y direction. This tensile rupture strength is obtained by holding each of the test pieces of the liquid acquisition layer 6 having a width of 25 mm and elongated in the X direction and the Y direction at a distance between the chucks of 100 mm and expanding the distance between the chucks at 100 mm / min. Is the maximum load measured at It should be noted that the tensile strength in a wet state in which artificial menstrual blood described later is absorbed by the liquid acquisition layer 6 is preferably 20% or more, and more preferably 30% or more of the strength when dried. preferable.
[0054]
If the liquid acquisition layer 6 has the above-described basis weight and tensile strength, the liquid acquisition layer 6 can easily maintain a three-dimensional shape when dry and wet when menstrual blood is absorbed, and menstrual blood repeatedly given by the concave portion of the liquid acquisition layer 6 can be obtained. The function of maintaining The liquid acquisition layer 6 may be other than the air-laid nonwoven fabric as long as it has the above-mentioned basis weight and tensile breaking strength.
[0055]
For example, an air-laid nonwoven fabric obtained by bonding only pulp with a binder may be used. Alternatively, a spunlaced nonwoven fabric in which cellulosic fibers and synthetic resin fibers are entangled by a water jet may be used. Alternatively, a spunlace nonwoven fabric mainly composed of at least one of pulp and rayon, which is a cellulosic fiber, and an air-through nonwoven fabric mainly composed of synthetic resin fibers may be integrated by water jet treatment or heat sealing. . Alternatively, the spunlace nonwoven fabric and the point-bonded nonwoven fabric, or the spunlace nonwoven fabric and the spunbonded nonwoven fabric similarly integrated, or a spunlace nonwoven fabric mainly composed of cellulosic fibers and a film having a large number of apertures are bonded. May be done.
[0056]
Further, when the liquid acquisition layer 6 is formed of various kinds of fibers, if the content of the cellulosic fiber is higher on the side facing the liquid permeable layer 5 than on the side facing the liquid absorbing layer 4, the liquid Menstrual blood is easily drawn from the permeable layer 5 to the liquid acquisition layer 6. Conversely, when the content of the cellulosic fiber is increased on the side facing the liquid absorbing layer 4, menstrual blood can be easily transferred to the liquid absorbing layer 4.
[0057]
As shown in FIG. 4, the liquid acquisition layer 6 is formed with vertical ribs 6a deformed so that the convex side faces the topsheet 3, and horizontal ribs 6b similarly deformed so that the convex side faces the topsheet 3. The vertical ribs 6a extend linearly in the vertical direction (Y direction), are positioned at equal intervals in the horizontal direction, and are formed parallel to each other. The horizontal rib 6b is formed so as to connect the adjacent vertical ribs 6a, 6a. The horizontal ribs 6b are formed in parallel at a certain interval in the vertical direction, but the horizontal ribs 6b adjacent in the horizontal direction are not located on the same line, and the horizontal ribs 6b arranged in the vertical direction and the adjacent horizontal ribs 6b And the horizontal ribs 6b arranged in the vertical direction are alternately arranged.
[0058]
At a portion surrounded by the vertical ribs 6a and the horizontal ribs 6b, a concave portion 6c which is depressed toward the liquid absorbing layer 4 is formed, and the concave portion 6c has a longer length in the Y direction than in the X direction. It is a large vertically long shape. The liquid acquisition layer 6 has a large number of the concave portions 6c arranged regularly.
[0059]
The liquid acquisition layer 6 has flat portions 6f, 6f in a range of a fixed width dimension Wa inward from both side edges 6h, 6h, and the flat portions 6f, 6f are not formed with the concave portions 6c. The flat portions 6f, 6f are wider than the width dimension described after the vertical rib 6a, and the width dimension Wa of the flat portion 6f is 1.2 to 10 times or more the width dimension of the vertical rib 6a, and more preferably 2 times. ~ 5 times. In this embodiment, flat portions 6f, 6f are formed on both sides of the liquid acquisition layer 6, and the concave portions 6c are regularly arranged in the entire region sandwiched between the flat portions 6f. However, a predetermined range inward from the front edge 6i and the rear edge 6j of the liquid acquisition layer 6 may be a flat portion. In this case, the width of the flat portion from the front edge 6i and the rear edge 6j is 1.2 to 10 times or more, and more preferably 2 to 5 times, the width of the horizontal rib 6b.
[0060]
As shown in FIG. 6, the height h1 from the lower surface of the recess 6c to the top of the vertical rib 6a is higher than the height h2 from the lower surface to the top of the horizontal rib 6b. As shown in FIG. 3, the tops of the vertical ribs 6a are in contact with the lower surface of the liquid permeable layer 5 and are bonded with a hot melt adhesive, and the lower surfaces of the recesses 6c are liquid with a hot melt adhesive. It is adhered to the upper surface of the absorption layer 4. That is, the top of each vertical rib 6a is located on the same plane, the top of each vertical rib 6a is in contact with the liquid permeable layer 5, and the lower surface of each recess 6c is located on the same plane. The lower surface of each concave portion 6c is in contact with the liquid absorbing layer 4. Further, the flat portions 6f, 6f of the liquid acquisition layer 6 are also adhered to the lower surface of the liquid permeable layer 5 with a hot melt adhesive.
[0061]
The hot melt adhesive is randomly applied to the lower surface of the liquid acquisition layer 6 (the surface facing the clothing side) and part of the surface of the liquid absorption layer 4 (the surface facing the skin side). Penetration of menstrual blood from the liquid acquisition layer 6 to the liquid acquisition layer 6 and penetration of menstrual blood from the liquid acquisition layer 6 to the liquid absorption layer 4 are not hindered by the hot melt adhesive.
[0062]
As described above, since the tops of the horizontal ribs 6b are lower than the tops of the vertical ribs 6a, at least some of the many horizontal ribs 6b have their tops bonded to the liquid permeable layer 5. Instead, a small gap is formed between the top of the horizontal rib 6b and the liquid permeable layer 5.
[0063]
As will be described later, the liquid acquisition layer 6 is formed in a three-dimensional shape by sandwiching a flat water-absorbent sheet 8 with a mold roll. At the time of shaping into a three-dimensional shape, since tensile stress concentrates on the wall 6e of the recess 6c, a force for separating fibers acts on the wall 6e, and the wall 6e has a vertical rib 6a. There is a portion where the fiber density is lower than the top portion, the top portion of the horizontal rib 6b, and the bottom portion 6d of the concave portion 6c. In addition, there is a portion in the wall 6e where a crack is generated due to the concentration of the stress. However, the fibers forming the water-absorbent sheet 8 are pressurized at the tops of the vertical ribs 6a and at the bottoms 6d of the recesses 6c, and the fiber density is high in this portion. Further, since the pressure during molding does not act on the flat portion 6f, the flat portion 6f has a lower density than the top of the vertical rib 6a and the bottom 6d of the recess 6c.
[0064]
Further, the average density of the liquid acquisition layer 6 is higher than that of the topsheet 3 and the liquid permeable layer 5, and the fiber density of the liquid absorption layer 4 below the average density of the liquid acquisition layer 6 is higher. . Since the vertical ribs 6a of the liquid acquisition layer 6 are in contact with the liquid permeable layer 5 and the bottoms 6d of the recesses 6c are in contact with the liquid absorption layer 4, menstrual blood flows from the top sheet 3 through the liquid permeable layer 5 due to the density gradient. It is easy to move to the liquid acquisition layer 6 and further to the liquid absorption layer 4 from the liquid acquisition layer 6. Further, as described above, since the fiber is separated from the wall portion 6e of the concave portion 6c of the liquid acquisition layer 6 and the density is reduced, and further, a crack is present, the fiber is temporarily retained in the concave portion 6c. Menstrual blood can be promptly transferred to the liquid absorbing layer 4.
[0065]
In order for menstrual blood to move quickly from the liquid guiding layer 5 to the liquid acquiring layer 6 and to be quickly given from the liquid acquiring layer 6 to the liquid absorbing layer 4, the average density of the liquid acquiring layer 6 is 0. 0.05 to 0.25 g / cm 3 The fiber density of the liquid absorbing layer 4 located below the liquid acquiring layer 6 is preferably 0.07 to 0.25 g / cm. 3 Is preferred.
[0066]
The width of the vertical rib 6a at the height of (1/2) · h1 and the width of the horizontal rib 6b at the height of (1/2) · h2 are 2 to 10 mm, and are preferably. 2 to 6 mm. The height h1 of the liquid acquisition layer 6 is 1.3 to 5 mm. In order that menstrual blood transmitted through the topsheet 3 can be sufficiently collected in the recess 6c, the opening area of the one recess 6c at a height of (1/2) · h2 is 5 to 20 mm. 2 The space volume of the concave portion 6c {the area × (height h1-the thickness of the water-absorbent sheet)} is 8 to 80 mm. 3 It is preferable that
[0067]
In addition, the aspect ratio of the opening dimension at the height position of (1/2) · h2 of one recess 6c, that is, (vertical dimension in the Y direction) / (width dimension in the X direction) is in the range of 1.1 to 10. Is more preferable, more preferably 1.5 to 7, and most preferably 2 to 5. When the aspect ratio is less than the above range, the function of vertically guiding menstrual blood obtained by the liquid acquisition layer 6 is reduced, and there is a possibility that diffusion in the horizontal direction may increase. When the horizontal ribs 6b are too wide apart from each other and receive a compressive force in the lateral direction from the thigh or the like, the elastic restoring force that tends to spread in the lateral direction decreases.
[0068]
In the liquid acquisition layer 6, the horizontal ribs 6b are formed at intervals in the vertical direction, so that the front edge 1c and the rear edge 1d approach the sanitary napkin 1 and on the skin side. When a force that bends so that the surface becomes concave acts, the liquid acquisition layer 6 tends to bend following this deformation. In particular, when the aspect ratio of the concave portion 6c is within the above range, the liquid acquisition layer 6 is easily curved in the above direction. Since the liquid acquisition layer 6 follows the curved deformation of the sanitary napkin 1, separation at the interface between the liquid acquisition layer 6 and the liquid permeable layer 5 is less likely to occur.
[0069]
As shown in FIG. 4, the horizontal ribs 6b are alternately arranged in the horizontal direction (X direction), so that the liquid acquisition layer 6 is easily curved in the vertical direction as described above. Furthermore, since the height h2 of the horizontal rib 6b is lower than the height of the vertical rib h1, the liquid acquisition layer 6 is easily deformed in the direction in which the side edges 6h and 6h are close to each other and the surface facing the skin side is concave. Become.
[0070]
The liquid absorption layer 4 is formed by adding aggregates of pulp such as pulverized pulp, mercerized pulp, and cross-link pulp to synthetic water-absorbing polymers such as polyacrylate, polyacrylamide, and anhydrous maleic acid; In this case, pulp and the above-mentioned synthetic water-absorbing polymer are wrapped with hydrophilic tissue paper.
[0071]
The back sheet 2 is a liquid-impermeable and air-permeable sheet, such as a polyethylene (PE) film or a polypropylene (PP) film in which fine air holes are formed. For example, CaCO on a plastic sheet 3 , BaSO 4 By mixing and stretching such inorganic fillers, fine air holes are appropriately dispersed and formed, and a film having improved air permeability and a thickness of about 15 to 50 μm can be formed.
[0072]
As shown in FIG. 2, liquid-impervious sheets 30 are provided on both left and right sides of the skin-side surface. In the wing portions 1A, 1A, the liquid-impervious sheets 30, 30 The top is bonded with hot melt adhesive. The liquid-impermeable sheet 30 is folded in two layers at equal distances to the left and right from the vertical center line Oy-Oy, and an elastic member 32 extending in the vertical direction is adhered to the inside thereof. Due to the elastic member 32, an elastic contraction force acts between the front portion and the rear portion of the sanitary napkin 1, and a force for bending the sanitary napkin 1 acts. Then, the liquid-impervious sheets 30, 30 rise and the leak-proof walls 31, 31 are formed.
[0073]
The liquid impermeable sheet is formed of a spunbonded nonwoven fabric, a meltblown nonwoven fabric, or a composite nonwoven fabric obtained by laminating these.
[0074]
The basis weight of the liquid absorbing layer 4 is the largest in the central region 20, and the basis weight of the portion sandwiched between the inner compressed grooves 11, 11 and the outer compressed grooves 16, 16 is smaller than that of the central region 20. The basis weight of the liquid absorbing layer 4 in other portions is equal to or slightly smaller than the portion sandwiched between the inner compressed grooves 11, 11 and the outer compressed grooves 16, 16.
[0075]
The preferred basis weight of the liquid absorbing layer 4 in the central region 20 is 400 to 1200 g / m. 2 And more preferably 500 to 1000 g / m 2 It is. A preferable basis weight of a portion sandwiched between the inner compressed grooves 11, 11 and the outer compressed grooves 16, 16 is 300 to 900 g / m. 2 And more preferably 350 to 600 g / m 2 It is. The preferred basis weight of the liquid absorbing layer 4 in the other part is 200 to 700 g / m2. 2 And more preferably 300 to 500 g / m. 2 It is.
[0076]
As a result, as shown in FIG. 2, the thickness increases in the central region 20, and in the central region 20, the skin-side surface has a shape that is greatly bulged toward the body.
[0077]
The vertical dimension of the central region 20, that is, the vertical interval between the front connection compression groove 12 and the rear connection compression groove 13 is 50 mm or more. The width dimension W1 of the central region 20 on the horizontal reference line Ox-Ox shown in FIG. 2 is determined according to the width of the female genitals. Since the average width of the crotch part of a woman is about 30 mm, the width dimension W1 is preferably in a range of 15 to 50 mm, and more preferably in a range of 20 to 40 mm.
[0078]
When the sanitary napkin 1 is worn on the body, a pressure-sensitive adhesive provided on the outer surface of the back sheet 2 is adhered to the inner surface of the crotch cloth 26 shown in FIG. Are bent toward the outer surface of the underwear so that the pressure-sensitive adhesive provided on the clothing side surface of the wings 1A, 1A is adhered to the outer surface of the crotch cloth 26.
[0079]
As shown in FIG. 2, in the sanitary napkin 1, the central region 20 is swelled toward the body, so that the central region 20 is easily adhered to the vaginal opening. The topsheet 3 located on the skin side surface of the central region 20 is a low-density air-through nonwoven fabric, and a liquid-permeable layer 5 of a bulky air-through nonwoven fabric is provided below the topsheet. Therefore, the contact feeling provided by the central region 20 to the above-mentioned parts of the body is soft.
[0080]
Menstrual blood excreted from the vaginal opening is mainly given to the central region 20. Since the topsheet 3 is a low-density nonwoven fabric, menstrual blood penetrates into the topsheet 3, but since the topsheet 3 contains fibers coated with a water-repellent oil agent, menstrual blood on the topsheet 3 is Spreading is suppressed. Since the liquid-permeable layer 5 located under the topsheet 3 is an air-through nonwoven fabric and has a void inside, menstrual blood passes through the void in the liquid-permeable layer 5 due to gravity, and the liquid underneath is obtained. Fall to layer 6. However, much of the menstrual blood given to the central region 20 quickly passes through the liquid permeation hole 25 and falls directly toward the liquid acquisition layer 6.
[0081]
Since the liquid acquisition layer 6 is formed of the water-absorbent sheet 8, menstrual blood that has fallen on the liquid acquisition layer 6 is absorbed by the water-absorbent sheet 8 and given to the liquid absorption layer 4 located thereunder. When a large amount of menstrual blood is given to the top sheet 3 at a time, the menstrual blood passes through the liquid permeation holes 25 and falls into the liquid acquisition layer 6, but the menstrual blood immediately enters the recess 6 c of the liquid acquisition layer 6. Since it is stored, even if the amount of menstrual blood excreted is large, it does not stay in the topsheet 3 or the liquid permeable layer 5 for a long time. Therefore, the skin-side surface of the central region 20 can maintain a state close to dryness, and it is difficult for the wearer's crotch to give a wet feeling or a stuffy feeling.
[0082]
Menstrual blood given to the concave portion 6c of the liquid acquisition layer 6 penetrates into the liquid absorbing layer 4 from the bottom 6d of the concave portion 6c, and penetrates through a low density portion or a crack in the wall portion 6e of the concave portion 6c to pass through the liquid absorbing layer. 4 is quickly absorbed. In addition, when a large amount of menstrual blood is given to the concave portion 6c and the amount of menstrual blood is larger than the space volume in any of the concave portions 6c, the menstrual blood passes over the low ribs 6b and extends vertically. It moves to the concave portion 6c adjacent in the direction. On the other hand, the vertical ribs 6a located on both sides of the concave portion 6c extend in parallel in the vertical direction and the tops thereof are in contact with and adhered to the liquid permeable layer 5, so that menstrual blood diffuses in the liquid acquisition layer 6 in the horizontal direction. It is difficult to do. Therefore, when a large amount of menstrual blood is given, this menstrual blood is absorbed by the liquid absorbing layer 4 while sequentially moving to the concave portions 6c arranged in the vertical direction.
[0083]
Further, flat portions 6f, 6f extending in the vertical direction are formed on both left and right sides of the liquid acquisition layer 6. Since the flat portions 6f, 6f have a lower fiber density than the vertical ribs 6a, even if menstrual blood is transmitted in the liquid acquisition layer 6 in the horizontal direction (X direction), the flat portions 6f, 6f diffuse in the horizontal direction. It can exert the function of stopping menstrual blood. Therefore, anxiety of leakage in the lateral direction can be reduced.
[0084]
Further, when menstrual blood further shifts from the both side edges 6h, 6h of the liquid acquisition layer 6, the menstrual blood is retained by the inner compressed grooves 11, 11 located on both sides, and further located on the outer side. As a result, the liquid leakage in the lateral direction from the sanitary napkin 1 can be effectively suppressed.
[0085]
Since the water-absorbent sheet 8 forming the liquid acquisition layer 6 contains synthetic resin fibers, the water-absorbent sheet 8 can maintain a three-dimensional shape even in a wet state where menstrual blood has been absorbed. Even if it works, when the pressure is removed, the three-dimensional shape shown in FIG. 4 can be restored. In particular, since the vertical ribs 6a and the horizontal ribs 6b are provided, the liquid acquisition layer 6 has an excellent elastic restoring function.
[0086]
Next, a method for manufacturing the sanitary napkin 1 will be described.
First, the step of shaping the liquid acquisition layer 6 into the three-dimensional shape shown in FIG. 4 will be described.
[0087]
FIG. 7 is a perspective view showing the upper mold 40 for forming the liquid acquisition layer 6, and FIG. 8 is a perspective view showing the lower mold 50. FIG. 9 is a sectional view of the upper mold 40 taken along line IX-IX.
[0088]
In the upper die 40 shown in FIG. 7, a plurality of convex portions 41 and a groove portion 42 located between the adjacent convex portions 41 extend in the vertical direction (Y direction) and are parallel to each other. Is formed. The convex portions 41 are formed with concave portions 43 at intervals in the vertical direction (Y direction). The concave portion 43 formed on any of the convex portions 41 is located between the concave portions 43 formed on the adjacent convex portions 41. That is, the concave portions 43 are alternately arranged between the adjacent convex portions 41.
[0089]
As shown in FIG. 9, at the boundary between the convex portion 41 and the concave portion 43, the end 41 a of the convex portion 41 is connected to the concave portion 43 in an arc curve. As shown in FIG. 9, the height H1 from the bottom surface 42a of the groove 42 to the top of the protrusion 41 is higher than the height H2 from the bottom 42a to the top of the recess 43.
[0090]
The lower mold 50 shown in FIG. 8 has ridges 51 extending in the vertical direction (Y direction) formed in parallel with each other, and a groove 52 is formed between the adjacent ridges 51, 51. The pitch of the adjacent convex portions 41 of the upper die 40 and the pitch of the adjacent groove portions 52 of the lower die 50 are the same.
[0091]
In a state where the surface of the upper mold 40 and the surface of the lower mold 50 are heated to about 120 ° C. lower than the melting point of polyethylene of the sheath of the core-sheath type synthetic fiber, as shown in FIG. The water absorbing sheet 8 is sandwiched between the lower mold 50 and the lower mold 50. The upper mold 40 and the lower mold 50 are combined so that the convex portion 41 enters the groove portion 52 and the convex ridge portion 51 enters the groove portion 42. However, a slight clearance is maintained between the top of the protrusion 41 of the upper mold 40 and the bottom of the groove 52 of the lower mold 50, and the top of the protrusion 51 of the lower mold 50 and the groove 42 of the upper mold 40 are kept. The upper mold 40 and the lower mold 50 are combined so that they are not pressed against each other so that a slight clearance is maintained between the upper mold 40 and the bottom.
[0092]
As a result, as shown in FIG. 10A, the vertical ribs 6a are formed by the ridges 51 of the lower mold 50, and the concaves 6c are formed by the protrusions 41 of the upper mold 40. Further, the water absorbing sheet 8 is lightly pressed by the concave portion 43 of the upper die 40, and the horizontal rib 6b is formed by the concave portion 43.
[0093]
Planes 44, 44 extending vertically are formed on both sides of the upper mold 40, and planes 53, 53 extending vertically are formed on both sides of the lower mold 50. Then, in the portion sandwiched between the flat surfaces 44, 44 and the flat surfaces 53, 53, the water absorbent sheet 8 is not pressed, and the flat portions 6f, 6f are formed.
[0094]
The upper mold 40 and the lower mold 50 are heated to a temperature slightly lower than the melting point of the composite synthetic fiber, and the water absorbing sheet 8 is sandwiched in a state where the upper mold 40 and the lower mold 50 maintain a clearance. Since the water absorbing sheet 8 is molded at the above-mentioned temperature and the molds are engaged with each other so as to have a clearance, the liquid acquisition layer 6 does not have a portion where the fibers are melted into a film shape and the liquid permeation function is improved. There is no hindrance. Further, by heating the composite synthetic fiber at a temperature at which it is softened, the three-dimensional shape shown in FIG. 4 can be maintained after molding.
[0095]
Since the concave portion 6c of the liquid acquisition layer 6 is formed by being pressed by the convex portion 41 having a short vertical dimension, the sheet serving as the wall portion 6e of the concave portion 6c is formed in both the X direction and the Y direction. The tensile stress concentrates. Therefore, the interval between the fibers forming the wall portion 6e of the concave portion 6c is widened, and a crack is generated in some places. At this time, by forming the vertical ribs 6a by pressing with the ridges 51 that are continuous in the vertical direction, the fiber density can be increased at the top of the vertical ribs 6a, and similarly, the fiber density at the bottom 6d of the recess 6c can be increased. Fiber density can also be increased. The fiber density at the top of the horizontal rib 6b is also higher than that of the wall 6e.
[0096]
When the liquid acquisition layer 6 is mass-produced, the upper mold 40 shown in FIG. 7 is formed on the roll surface so that the Y direction is the circumferential direction and the X direction is the axial direction, and the lower mold 50 shown in FIG. The rolls are formed on the roll surface such that the Y direction is the circumferential direction and the X direction is the axial direction. Both rolls face each other with a clearance therebetween, and the water absorbing sheet 8 is supplied between them to form the liquid acquisition layer 6. .
[0097]
In the manufacturing process of the sanitary napkin 1, the surface sheet 3 and the liquid permeable layer 5 are overlapped to form the liquid permeable holes 25. Next, the vertical ribs 6a and the flat portions 6f, 6f of the liquid acquisition layer 6 are bonded to the back of the liquid permeable layer 5 with a hot melt adhesive. Further, the lower surface of the concave portion 6c of the liquid acquisition layer is bonded to the liquid absorption layer 4 with a hot melt adhesive. The compression groove 10 is formed in a state where the topsheet 3, the liquid permeable layer 5, the liquid acquisition layer 6, and the liquid absorption layer 4 are stacked. Thereafter, the back sheet 2 is overlaid on and adhered to the clothing-side surface of the liquid absorbing layer 4, and the liquid-impermeable sheet 30 is adhered to the skin-side surface.
[0098]
Flat portions 6f, 6f extending in the vertical direction are formed on both side portions of the liquid acquisition layer 6, and the flat portions 6f, 6f are such that the space between the fibers is widened like the wall portion 6e of the concave portion 6c. And has a certain degree of rigidity and a uniform density. Therefore, in the assembling process of the sanitary napkin 1, it is possible to convey the liquid acquisition layer 6 by suctioning the flat portions 6f and 6f to, for example, a suction belt. It can be supplied while maintaining its shape.
[0099]
The liquid acquisition layer 6 can be formed by a single water-absorbent sheet 8, but can also be formed by stacking a plurality of water-absorbent sheets 8. FIG. 5B shows an example in which the liquid acquisition layer 6 is formed by stacking two water absorbent sheets 8A and 8B. Each of the two water absorbent sheets 8A and 8B is formed of the same material as the water absorbent sheet 8.
[0100]
When the liquid acquisition layer 6 is formed into a three-dimensional shape, tension is applied to the wall 6e of the concave portion 6c to widen the interval between the fibers, and a crack is formed in some places. However, when a plurality of water-absorbent sheets are used in an overlapping manner, a portion where the fiber density is low or a portion where a crack occurs in each of the plurality of water-absorbent sheets in the wall portion 6e is different, and concentrated at one place. Will not be done. Therefore, it is possible to prevent the overall strength of the wall portion 6e of the concave portion 6c from being reduced, and it is possible to enhance the resilience to the three-dimensional shape after the body pressure acts and the flat portion is crushed.
[0101]
In addition, one in which a plurality of water-absorbent sheets are partially adhered can be used. When a plurality of water-absorbent sheets contain thermoplastic fibers, the water-absorbent sheets can be bonded together by fusing the fibers together. Alternatively, the water-absorbing sheet may be bonded with an adhesive. As shown in FIGS. 7 to 10, when the liquid acquisition layer 6 is formed into a three-dimensional shape using a heated mold, the heat of the mold can be used to bond the absorbent sheet at a pressure that does not form a film. Alternatively, a plurality of water-absorbent sheets may be thermally bonded in advance with a dot-shaped bonding portion, and the liquid acquisition layer 6 may be formed into a three-dimensional shape by a laminate of the heat-bonded absorbent sheets.
[0102]
When joining a plurality of absorbent sheets, the joining portion may be any one of the vertical rib 6a, the horizontal rib 6b, the wall 6e of the recess 6c, and the bottom 6d of the recess. Alternatively, the joints may be randomly formed in all the portions. However, it is preferable that the liquid absorbing sheets are joined together at least at the wall 6e of the recess 6c.
[0103]
When the adhesive portion between the water absorbing sheets is provided at the portions of the vertical ribs 6a and the horizontal ribs 6b, the skeleton structure of the vertical ribs 6a and the horizontal ribs 6b can be strengthened. In addition, since the fiber density is extremely low in the wall portion 6e of the concave portion 6c as described above, if the adhesive portion of the water-absorbing sheet is provided at this portion, the rigidity of the concave portion 6c is increased and the concave portion 6c Shape can be easily maintained. Further, when an adhesive portion is provided on the bottom 6d of the recess 6c, the density of this portion can be increased, and as a result, menstrual blood given to the liquid acquisition layer 6 is concentrated on the bottom 6d of the recess 6c. It can be provided to the liquid absorbing layer 4.
[0104]
FIG. 11 is a plan view showing a sanitary napkin 100 according to a second embodiment of the absorbent article of the present invention. The same components as those in the embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0105]
This sanitary napkin 100 is a long type suitable for use during bedtime and the like, has a total length dimension of approximately 200 to 450 mm in the vertical direction (Y direction), and has both side edges 1a and 1b in the horizontal direction. The rear flaps 1B, 1B are formed so as to expand so as to gradually widen from the reference line Ox-Ox toward the rear edge 1d, and to hit the buttocks.
[0106]
On the skin side surface, inner compression grooves 11, 11 are formed in a vertically long shape. The front portions 11A, 11A of the inner compression portions 11, 11 are arc-shaped curved patterns protruding toward the longitudinal center line Oy-Oy. The inner compressed grooves 11, 11 are formed with inflection portions 11B, 11B whose opposing gaps are widened behind the front portions 11A, 11A. The rear portions 11D, 11D further move toward the rear edge 1d. Therefore, it gradually narrows and is connected to each other by the rear connection compression groove 13A.
[0107]
The portion surrounded by the inner compression grooves 11, 11, the front connection compression groove 12, and the rear connection groove 13A is the central region 20. In the central region 20, the portion sandwiched by the front portions 11A, 11A is mainly the front central region 20A facing the female vaginal opening, and the portion sandwiched by the inflection portions 11B, 11B is mainly female. Is a middle central region 20B facing the perineum, and a portion sandwiched between the rear portions 11D, 11D is a rear central region 20D mainly facing the groove of the anus and the buttocks.
[0108]
Outer compressed grooves 16, 16 similar to FIG. 1 are formed on the left and right outer sides of the front portions 11A, 11A of the inner compressed grooves 11, 11, respectively, and left and right of the rear portions 11D, 11D of the inner compressed grooves 11, 11. Outer rear compression grooves 17, 17 are formed on the outside, and the rear outer compression grooves 17, 17 are connected to each other inside the rear edge 1d.
[0109]
In this embodiment, the liquid permeable layer 5 is provided in a band shape from the front edge 1c to the rear edge 1d, and the central region 20 has the same three-dimensional liquid acquisition as shown in FIG. A layer 6 is provided.
[0110]
The central region 20 is formed such that the longitudinal length from the front connection compression groove 12 to the rear connection compression groove 13A is in a long range of 120 to 350 mm, but the liquid acquisition layer 6 faces at least the vaginal opening. It is provided in the front central area 20A which is a part. Alternatively, as shown in FIG. 11, the liquid acquisition layer 6 may be provided over the front central region 20A and the middle central region 20B facing the perineum.
[0111]
【Example】
Form the following layers
(A) Top sheet 3
An air-through nonwoven fabric formed of a core-sheath type composite synthetic fiber (2.2 dtex, fiber length: 44 mm) of polyethylene terephthalate containing titanium oxide at a ratio of 1.1% of the fiber mass and having a core of polyethylene and a sheath of polyethylene. Is 25g / m 2 Was used.
[0112]
In the following measurement, the one having a width of 130 mm, a length of 200 mm and a weight of 0.637 g was used.
[0113]
(B) Liquid permeable layer 5
Air-through nonwoven fabric of core-sheath type composite synthetic fiber (4.4 dtex, fiber length 50 mm) having a core of polypropylene and a sheath of polyethylene having an eccentric cross section, with a basis weight of 20 g / m2 2 ), The average thickness is 1.75 mm and the average density is 0.0175 g / cm 3 Was used in a three-fold configuration.
[0114]
In the following measurements, a sample having a width of 100 mm, a length of 200 mm and a weight of 0.415 g was used.
[0115]
(C) Liquid permeation hole 25
The surface sheet 3 and the liquid permeable layer 5 are overlapped, and a liquid permeable hole 25 penetrating the liquid permeable layer 5 from the surface sheet 3 with a roll having a pin at 100 ° C. and a roll at 70 ° C. having a hole into which the pin enters. Was formed. The opening diameter of the liquid permeable holes 25 was 2 mm, and the pitch was 5.5 mm in the Y direction and 3.5 mm in the X direction.
[0116]
(D) Liquid acquisition layer 6
60% by mass of chemical pulp, 26% by mass of a core-in-sheath type composite synthetic fiber (1.7 dtex, fiber length 13 mm) having polyethylene terephthalate as a core and polyethylene as a sheath, and 14% of an ethylene-vinyl acetate copolymer emulsion adhesive. Air-laid non-woven fabric (air-laid pulp) containing 40% by mass with a basis weight of 40 g / m 2 This was used as the water-absorbing sheet 8 by folding it in two layers.
[0117]
In the following measurements, a sample having a width of 50 mm, a length of 100 mm and a weight of 0.205 g was used.
[0118]
In Comparative Example 1 in Table 1, the water-absorbent sheet 8 was used as it was as the liquid acquisition layer 6 without deforming it three-dimensionally. The average thickness of the water-absorbent sheet 8 in a dry state measured five times was 0.928 mm.
[0119]
The average density of the water-absorbent sheet 8 before molding into a three-dimensional shape is 0.075 g / cm. 3 The tensile rupture strength at the time of drying in the Y direction and the X direction measured after the liquid acquisition layer 6 was formed into a three-dimensional shape was 3.46 N / 25 mm and 2.83 N / 25 mm, respectively.
[0120]
The liquid absorbing layer 6 was obtained by three-dimensionally molding the water absorbing sheet 8. The width of the vertical rib 6a at the height of h1 / 2 is 3 mm, the width of the horizontal rib 6b at the height of h2 / 2 is 2.5 mm, and the opening area of the recess 6c at the height of h2 / 2. 15 mm 2 And
[0121]
However, in each of Comparative Example 2 and Examples 1 to 8 shown in Table 1, the thickness of the liquid acquisition layer 6 in a dry state was changed by changing the clearance between the upper mold 40 and the lower mold 50 (FIG. 6). H1) was changed.
[0122]
In Comparative Example 2, since the thickness was 1.192 mm, the space volume of the concave portion 6c was {15 × (1.192−0.928)} = 3.96 mm. 3 Calculating similarly, Example 2 having the smallest thickness among the examples is 8.61 mm. 3 Example 8 having the largest thickness is 32.64 mm 3 It is. That is, the space volume of the concave portion in the embodiment is from 8.61 to 32.64 mm. 3 Met.
[0123]
(E) Liquid absorption layer 4
8 g of chemical pulp and 0.15 g of a water-absorbing polymer are uniformly mixed, and the width is 70 mm, the length is 200 mm, and the density is 0.069 g / cm. 3 15g / m 2 The liquid absorbent layer 4 was wrapped with tissue paper.
[0124]
(1) Measurement of thickness
The thickness was measured with UF-60A manufactured by Daiei Kagaku Seiki Seisaku-Sho, Ltd. during the drying and after the pressurization in the wet state.
[0125]
(2) Drip test
Each liquid acquisition layer 6 of Comparative Example 1 to Example 8 in Table 1 is fixed to an opening of a beaker having a volume of 50 ml. The artificial menstrual blood is continuously dropped at a flow rate of 3 ml / min using an auto burette from a position 5 mm above the central part of the liquid acquisition layer 6. Then, the time from the start of the drop until the liquid first dropped into the beaker was measured (unit: seconds).
[0126]
Here, artificial menstrual blood used was prepared by adding 300 g of glycerin, 30 g of sodium salt of carboxymethylcellulose, and 40 g of sodium chloride to 4 liters of ion-exchanged water, stirring and coloring with red food red.
[0127]
(3) Pressure absorption test
As shown in FIG. 12 (B), on the flat test table 61, the liquid absorbing layer 4, the liquid obtaining layer 6, and the liquid permeable layer 5 and the surface sheet 3 integrated are sequentially stacked. An acrylic plate 62 having the dimensions shown in FIG. 12A is installed at the uppermost part such that the opening 62a thereof coincides with the center. Then, weights 63, 63 each of 900 g are placed before and after the opening 62a. In addition, the self-weight of the acrylic plate was 115 g.
[0128]
The artificial menstrual blood is given into the opening 62a at a flow rate of 95 ml / min using an autoburette. At the first time, 3 ml is given, and the time (second) from when the supply of the liquid is started to when the liquid on the surface of the topsheet 3 is exhausted at the opening 62a is measured. After 30 seconds have passed since the liquid disappeared on the surface of the topsheet 3 for the first time, 4 ml was given for the second time and the permeation time was measured in the same manner. After 5 minutes have passed after the second liquid disappeared from the surface of the topsheet 3, 3 ml of the liquid was given as a third liquid, and the permeation time was measured in the same manner.
[0129]
After a lapse of one minute after the third supply of liquid from the surface of the topsheet 3, the acrylic plate 62 and the weights 63, 63 are removed, and the thickness of each liquid acquisition layer 6 is measured. In addition, (thickness after pressing / thickness after drying) × 100 (%) was calculated as a thickness change rate.
The measurement results are shown in Table 1 below.
[0130]
[Table 1]
Figure 2004181087
[0131]
From Table 1, it was confirmed that in each example, the drip property and the liquid permeability in the pressure water absorption test were good.
[0132]
In the above embodiment, the liquid guide layer 5 is provided below the topsheet 3 and the liquid acquisition layer 6 is provided thereunder. However, the liquid acquisition layer 6 is provided directly below the topsheet 3. May be present.
[0133]
【The invention's effect】
As described above, in the present invention, when a large amount of liquid is applied at one time, the liquid can be held under the topsheet and then immediately absorbed by the liquid absorption layer, and the remaining liquid on the topsheet can be reduced. Can be prevented.
[Brief description of the drawings]
FIG. 1 is a plan view showing a sanitary napkin according to an embodiment of an absorbent article of the present invention;
FIG. 2 is a cross-sectional view taken along the line II-II of the state in which the sanitary napkin shown in FIG.
FIG. 3 is an enlarged sectional view showing an open state of a liquid permeation hole and a liquid acquisition layer.
FIG. 4 is a perspective view of a liquid acquisition layer,
FIG. 5 is a sectional view taken along line VV in FIG. 4;
FIG. 6 is a sectional view taken along line VI-VI of FIG. 4;
FIG. 7 is a perspective view of an upper mold for forming a three-dimensional liquid acquisition layer,
FIG. 8 is a perspective view of a lower mold for forming a three-dimensional liquid acquisition layer,
9 is a sectional view taken along line IX-IX of FIG.
FIG. 10 is a cross-sectional view showing a state in which the liquid acquisition layer is three-dimensionally molded with the upper mold and the lower mold.
FIG. 11 is a plan view showing a vertically long sanitary napkin as an absorbent article according to a second embodiment of the present invention;
12A is a plan view of an acrylic plate used in a pressure absorption test, FIG. 12B is a cross-sectional view illustrating the pressure absorption test,
[Explanation of symbols]
1 sanitary napkin
2 Back sheet
3 Top sheet
4 liquid absorption layer
5 Liquid permeable layer
6 liquid acquisition layer
6a Vertical rib
6b Horizontal rib
6c recess
6d bottom
10 Compression groove
11 Inside compression groove
20 Central area
25 Liquid permeation hole

Claims (8)

肌側表面に位置する液透過性の表面シートと、着衣側表面に位置する裏面シートと、前記表面シートと前記裏面シートとの間に位置する液吸収層とを備えた吸収性物品において、
前記液吸収層の前記表面シートに向く表面に液獲得層が設置されており、前記液獲得層は、吸水性シートが、その厚み方向に向けて立体的に変形した状態を保つものであり、
その立体形状は、前記表面シートに向けて凸状で且つ縦方向に延びる縦リブが互いに平行に形成されているとともに、前記表面シートに向けて凸状で且つ横方向に延びる横リブが、縦方向に間隔を開けて前記縦リブ間を繋ぐように形成され、前記縦リブと横リブとで囲まれた多数の凹部が前記液吸収層に向けて窪んで形成されており、
少なくとも前記縦リブが、前記表面シートに接し、あるいは表面シートの下に位置する液透過層に接し、前記凹部の底部が前記液吸収層に接していることを特徴とする吸収性物品。A liquid-permeable top sheet located on the skin side surface, a back sheet located on the clothing side surface, and an absorbent article comprising a liquid absorbing layer located between the top sheet and the back sheet.
A liquid acquisition layer is provided on the surface of the liquid absorption layer facing the topsheet, and the liquid acquisition layer is one in which the water-absorbent sheet maintains a three-dimensionally deformed state in its thickness direction.
The three-dimensional shape is such that vertical ribs protruding toward the topsheet and extending in the vertical direction are formed in parallel with each other, and horizontal ribs protruding toward the topsheet and extending in the horizontal direction are vertical. Are formed so as to connect the vertical ribs at intervals in the direction, and a number of concave portions surrounded by the vertical ribs and the horizontal ribs are formed to be depressed toward the liquid absorbing layer,
An absorbent article characterized in that at least the vertical ribs are in contact with the topsheet, or in contact with a liquid permeable layer located below the topsheet, and the bottom of the recess is in contact with the liquid absorption layer. 前記凹部の底部から前記横リブの頂部までの高さ寸法が、前記凹部の底部から前記縦リブの頂部までの高さ寸法よりも低い請求項１記載の吸収性物品。2. The absorbent article according to claim 1, wherein a height from the bottom of the recess to the top of the horizontal rib is lower than a height from the bottom of the recess to the top of the vertical rib. 3. それぞれの前記凹部は、横方向の幅寸法よりも縦方向の長さ寸法が長い縦長である請求項１または２記載の吸収性物品。3. The absorbent article according to claim 1, wherein each of the concave portions has a vertically long length in a vertical direction longer than a width in a horizontal direction. 4. １つの凹部の空間容積が８〜８０ｍｍ３である請求項１ないし３のいずれかに記載の吸収性物品。Claims 1 space volume of one recess is 8～80Mm 3 to absorbent article according to any one of the three. 前記液獲得層は、前記吸水性シートが立体的に変形させられる際の引っ張り応力の集中により繊維間の間隔が広げられて低密度とされた部分を有する請求項１ないし４のいずれかに記載の吸収性物品。5. The liquid acquisition layer according to claim 1, wherein the space between the fibers is widened due to a concentration of tensile stress when the water-absorbent sheet is three-dimensionally deformed, and has a low density. 6. Absorbent articles. 前記液獲得層には、前記縦リブよりも幅が広い平坦部が、縦方向に連続して形成されている請求項１ないし５のいずれかに記載の吸収性物品。The absorbent article according to any one of claims 1 to 5, wherein a flat portion having a width wider than the vertical rib is formed in the liquid acquisition layer so as to be continuous in a vertical direction. 前記液獲得層は、複数枚の前記吸水性シートが重ねられて、この複数枚の吸水性シートが一緒に立体形状とされたものである請求項１ないし６のいずれかに記載の吸収性物品。The absorbent article according to any one of claims 1 to 6, wherein the liquid acquisition layer is formed by stacking a plurality of the water-absorbent sheets and forming the plurality of water-absorbent sheets together into a three-dimensional shape. . 乾燥状態の前記液獲得層を縦方向に引っ張ったときの破断強度が２５ｍｍ幅あたり２．５Ｎ以上である請求項１ないし７のいずれかに記載の吸収性物品。The absorbent article according to any one of claims 1 to 7, wherein a breaking strength when the liquid acquisition layer in a dry state is pulled in a longitudinal direction is 2.5 N or more per 25 mm width.
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JP2008113866A (en) * 2006-11-06 2008-05-22 Uni Charm Corp Absorbent article
JP2009261476A (en) * 2008-04-23 2009-11-12 Kao Corp Absorbent article
JP2011120654A (en) * 2009-12-08 2011-06-23 Kao Corp Absorbent article
JP2011167573A (en) * 2011-06-09 2011-09-01 Kao Corp Absorptive article
JP2019187645A (en) * 2018-04-20 2019-10-31 ユニ・チャーム株式会社 Absorbent article
JP2020014663A (en) * 2018-07-25 2020-01-30 王子ホールディングス株式会社 Absorbent article

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