JP4442932B2 - Liquid impermeable sheet for absorbent articles - Google Patents

Liquid impermeable sheet for absorbent articles Download PDF

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JP4442932B2
JP4442932B2 JP52345498A JP52345498A JP4442932B2 JP 4442932 B2 JP4442932 B2 JP 4442932B2 JP 52345498 A JP52345498 A JP 52345498A JP 52345498 A JP52345498 A JP 52345498A JP 4442932 B2 JP4442932 B2 JP 4442932B2
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nonwoven fabric
fiber
liquid
sheet
polymer
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JP2001504723A (en
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義実 辻山
真吾 堀内
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JNC Corp
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Chisso Corp
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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
    • A61F13/51—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the outer layers
    • A61F13/514—Backsheet, i.e. the impermeable cover or layer furthest from the skin
    • A61F13/51401—Backsheet, i.e. the impermeable cover or layer furthest from the skin characterised by the material
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F13/00—Bandages or dressings; Absorbent pads
    • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/15203—Properties of the article, e.g. stiffness or absorbency
    • 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
    • A61F13/15203—Properties of the article, e.g. stiffness or absorbency
    • A61F2013/15284—Properties of the article, e.g. stiffness or absorbency characterized by quantifiable properties
    • A61F2013/15406—Basis weight
    • 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
    • A61F13/15203—Properties of the article, e.g. stiffness or absorbency
    • A61F2013/15284—Properties of the article, e.g. stiffness or absorbency characterized by quantifiable properties
    • A61F2013/15422—Density
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F13/00—Bandages or dressings; Absorbent pads
    • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/51—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the outer layers
    • A61F2013/51002—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the outer layers with special fibres
    • A61F2013/51009—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the outer layers with special fibres characterized by the shape of the fibres
    • A61F2013/51011—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the outer layers with special fibres characterized by the shape of the fibres characterized by the count of the fibres, e.g. denier or tex
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
    • Y10T442/608—Including strand or fiber material which is of specific structural definition
    • Y10T442/614—Strand or fiber material specified as having microdimensions [i.e., microfiber]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
    • Y10T442/608—Including strand or fiber material which is of specific structural definition
    • Y10T442/614—Strand or fiber material specified as having microdimensions [i.e., microfiber]
    • Y10T442/622—Microfiber is a composite fiber
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
    • Y10T442/608—Including strand or fiber material which is of specific structural definition
    • Y10T442/614—Strand or fiber material specified as having microdimensions [i.e., microfiber]
    • Y10T442/626—Microfiber is synthetic polymer
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
    • Y10T442/637—Including strand or fiber material which is a monofilament composed of two or more polymeric materials in physically distinct relationship [e.g., sheath-core, side-by-side, islands-in-sea, fibrils-in-matrix, etc.] or composed of physical blend of chemically different polymeric materials or a physical blend of a polymeric material and a filler material
    • Y10T442/64—Islands-in-sea multicomponent strand or fiber material
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
    • Y10T442/659—Including an additional nonwoven fabric

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

Description

技術分野
本発明は、医療衛生材料の紙おむつ、生理用ナプキン等の吸収性物品用液体非透過性シート及びそれを用いた吸収性物品に関する。さらに詳しくは、通気性と風合いが良好で、かつ液体非透過性を有し、吸収性物品用液体非透過性シート及び前記液体非透過性シートをその一部に用いた吸収性物品に関するものである。
背景技術
従来から医療衛生材料の紙おむつ、生理用ナプキン等の吸収性物品は、尿や血液などの体液を吸収し漏れを防止するため、少なくとも、尿や血液などの体液を吸収し保持する液体吸収層と、その表面側（肌に接する側）に配置される例えば不織布、織布または編布などからなる液体透過性の表カバーと、裏側面に配置され、吸収した体液が外部にもれるのを防ぐための液体非透過性バックシートとを有する構成となっている。また、通常、紙おむつや生理用ナプキン等の吸収性物品においては、バックシートのほかにも、吸収性物品が身体の動きによって所定の着用状態から位置がずれたり、横向きに寝転んだりした場合に、吸収した体液などの液体が漏れるのを防止するために吸収性物品の両脇に撥水性シートからなるサイドシート（紙おむつなどの場合にはギャザーが付与されている場合が多いのでサイドギャザーとかレッグカフなどとも言われており、紙おむつの場合には、サイドシートは紙おむつを着用した場合に太もものつけね又は太ももを回ってそれを把持する様な位置に設けられている。）なども設けられていたり、また、紙おむつに於いては、更に腹部などを覆う部分やその反対側の臀部上部を覆う部分の肌側には、吸収した体液などの液体が、転んだり、寝転んだり、身体を回転させるなど着用者の動きにより、腹部や臀部上部に漏れてきた場合にそれを吸水性物品外に漏らさないようにするための撥水性のラウンドシートなども設けられている。更に紙おむつなどの場合には、ウェスト位置肌側に帯状にウェストギャザーなどが設けられているものもあり、これらも撥水性のシートで構成されている。
また、液体吸収層には、例えばフラッフパルプなどのセルロース系繊維、高吸水性ポリマー、必要に応じ合成繊維の混合物などからなる適宜の各種液体吸収層が使用されている。
そして、一般には、これら吸収性物品のバックシートには比較的液体非透過性が大きいことが要求される液体非透過性シートが、また、サイドシート、ラウンドシートならびにウェストギャザーなどは、前記バックシートほどの液体非透過性を有していないが、撥水性を有するシートが用いられている。
従来これらの吸収性物品のバックシートとしては熱可塑性フィルムが使用されている。該熱可塑性フィルムは、着用中の内部の蒸れを防止するために無数の微細孔を有し、通気性をもたせることが一般的である。また、フィルム特有のプラスチック性の感触と外観を改良し、また、強力を改良する観点から不織布と複合化させたものも使用されている。また、サイドシートやラウンドシートならびにウェストギャザーなどは、撥水性などを付与した不織布が用いられている。
この様に、吸収性物品の構成部品として、液体非透過性シートや撥水性シートが用いられる部分がある。
前述した様に、吸収性物品のバックシートには、一般に通気性をもたせた熱可塑性フィルムなどが用いられているが、液体非透過性と通気性の相反する性能が要求され、この両者を十分満足するバックシートと言う観点から未だ不充分である。すなわち、熱可塑性フィルムを用いた場合は液体非透過性は満足できるが、通気性の点が十分ではない。また、サイドシートやラウンドシートならびにウェストギャザーなどに使用される素材は、前述した様に撥水性などを付与した不織布が用いられているが、通気性を余り犠牲にすることなく、更に液体非透過性を付与できればより好ましい。
特許第２５３３２５３号（特開平４−２２６６５８号公報）では、吸収体とプラスチックフィルムからなるバックシートとの間に液漏れ防止と布様肌合いを維持するために液体非透過性バッフル層を付与しているが、複雑な構造となり重量がアップする。
また、特開平６−１４９４９号公報では、吸収体とプラスチックフィルムとの間に不透液性シートを設けているが、未だ不充分である。
本発明の目的は、通気性が良好で、かつ液体非透過性を保持し、風合いの良好な吸収性物品用液体非透過性シートならびにそれを用いた吸収性物品を提供することにある。また、本発明の目的は前記優れた性質を有し、更により強力の優れた吸収性物品用液体非透過性シートならびにこれを用いた吸収性物品を提供することにある。
発明の開示
前記目的を達成するため、本発明の吸収性物品用液体非透過性シートは、メルトブロー不織布に熱可塑性ポリマーからなる繊維不織布が積層されてなる吸収性物品用液体非透過性シートであり、前記熱可塑性ポリマーからなる繊維不織布は、スパンボンド法で製造される長繊維不織布であり、前記メルトブロー不織布は、混繊型の紡糸口金を用いてメルトブロー法で紡糸された、融点差が１５℃以上である低融点ポリマーの極細繊維と高融点ポリマーの極細繊維とからなる繊維径１０μｍ以下の熱可塑性極細繊維の混繊品であり、紡糸捕集後に未加工であるかまたは平滑ロールによって圧密化されたメルトブロー不織布であり、前記メルトブロー不織布は、下記Ａ、Ｂ式を満足することを特徴とする。
２≦Ｗ／Ｄ2≦２００・・・・（Ａ）
０．０５≦ｄ≦０．２・・・・（Ｂ）
Ｗ：目付ｇ／ｍ2
Ｄ：繊維径μｍ
ｄ：不織布の見かけ密度ｇ／ｃｃ
また前記本発明のシートにおいては、液体非透過性シートが、吸収性物品のバックシート、サイドシート、ラウンドシート及びウェストギャザーから選ばれる少なくとも１種であることが好ましい。
また前記本発明のシートにおいては、メルトブロー不織布が、好ましくはポリオレフィン系及びポリエステル系から選ばれる少なくとも一つのポリマーであることが好ましい。
また前記本発明のシートにおいては、メルトブロー不織布の平均繊維径が、０．１〜９μｍの範囲であることが好ましい。
また前記本発明のシートにおいては、メルトブロー不織布の目付けが、４〜５０ｇ／ｍ２の範囲であることが好ましい。
また前記本発明のシートにおいては、熱可塑性繊維不織布が、低融点ポリマーと高融点ポリマーとを複合化させた二成分複合繊維であることが好ましい。
また前記本発明のシートにおいては、複合繊維の高融点ポリマー成分と低融点ポリマー成分との融点差が、１５℃以上であることが好ましい。
また前記本発明のシートにおいては、複合繊維が、芯鞘型、偏心鞘芯型、並列型、多層型及び海島型の複合繊維から選ばれる少なくとも１つの繊維であることが好ましい。
また前記本発明のシートにおいては、複合繊維を構成するポリマー成分が、ポリオレフィン系、ポリエステル系及びポリアミド系から選ばれる少なくとも一つのポリマーであることが好ましい。
また前記本発明のシートにおいては、不織布を構成する繊維の断面形状が、円形断面、異形断面、中空断面形状から選ばれる少なくとも一つの形状であることが好ましい。
また前記本発明のシートにおいては、メルトブロー不織布と積層用の繊維不織布の積層が、エンボスロールによる熱接着、超音波溶着、低融点ポリマー成分の融点以上で高融点ポリマー成分の融点未満の温度の熱風を利用した熱風循環接着、ホットメルトポリマーを使用したホットメルト接着から選ばれる少なくとも一つの接着による積層であることが好ましい。
次に本発明の本発明の吸収性物品は、前記本発明の液体非透過性シートを一部に用いたことを特徴とする。
本発明の吸収性物品用液体非透過性シートを構成する不織布は、メルトブロー法で紡糸された繊維径が１０μｍ以下の熱可塑性極細繊維不織布であって、該不織布は、前記式（Ａ）、（Ｂ）式を満足することにより、通気性が良好で液体非透過性を保持することができ、風合、柔軟性もすぐれた吸収性物品に好適に用いられる液体非透過性シートを提供できる。
更に、前記メルトブロー不織布とそれとは別の熱可塑性繊維不織布の積層体を用いる本発明の好ましい態様とすることによって、不織布強力が強く、風合いが良好な吸収性物品に好適に用いられる液体非透過性シートを提供できる。
また、メルトブロー不織布を、融点差が１５℃以上である低融点ポリマーと高融点ポリマーとを複合化させた繊維径１０μｍ以下の熱可塑性極細複合繊維からなる不織布とする本発明の好ましい態様とすることにより、毛羽立ちの少ない吸収性物品に好適に用いられる液体非透過性シートを提供できる。
また、メルトブロー不織布を、融点差が１５℃以上である低融点ポリマーの極細繊維と高融点ポリマーの極細繊維とからなる繊維径１０μｍ以下の熱可塑性極細繊維の混繊品からなる不織布とする本発明の好ましい態様とすることにより、毛羽立ちの少ない吸収性物品に好適に用いられる液体非透過性シートを提供できる。
また、前記メルトブロー不織布と積層する熱可塑性繊維不織布が、長繊維不織布である本発明の好ましい態様とすることにより、毛羽立ちが少なく不織布強力の強い吸収性物品に好適に用いられる液体非透過性シートを提供できる。
また、液体非透過性シートが、吸収性物品のバックシート、サイドシート、ラウンドシート及びウェストギャザーから選ばれた少なくとも１種である本発明の好ましい態様とすることにより、通気性が良好で液体非透過性を保持する作用が効果的に発揮され、風合、柔軟性もすぐれた吸収性物品を製造するのに好適に用いられる。
また、前記の液体非透過性シートを一部に用いた本発明の吸収性物品は、体液の吸収性物品外への漏れもなく、通気性が良好でかつ風合も良好な吸収性物品を提供できる。
【図面の簡単な説明】
図１は、本発明の液体非透過性シートをその一部に用いた紙おむつの一例の、肌側から見た展開平面図である。
図２は、図１のＸ−Ｘ´部分の断面の概略端面図である。
図３は、図１のＹ−Ｙ´部分の断面の概略端面図である。
図４は、本発明の液体非透過性シートをその一部に用いた生理用ナプキンの一例の、肌側から見た展開平面図である。
図５は、図４のＸ−Ｘ´部分の断面の概略端面図である。
発明を実施するための最良の形態
本発明の吸収性物品の液体非透過性シートに用いられる不織布は、メルトブロー法で紡糸された不織布である。
メルトブロー不織布は、良く知られているので詳細説明は省略するが、熱可塑性ポリマーを溶融押出しにより、メルトブロー紡糸口金から溶融されたポリマーを繊維状に押出し、それと同時にその紡糸オリフィス周囲に設けられたスリットから高温高速の気体を噴射させ、押出された繊維状の溶融ポリマーの流れに吹き当てる。その高速気流の作用によって押出された繊維状の溶融ポリマーをけん引して極細繊維流として、捕集用無端ネット状コンベアーなどの補集装置上に堆積して極細繊維ウェッブとし、必要に応じ熱融着処理する事によって不織布にしたものである。（特開平１−１５６５６１号公報、インダストリアル・アンド・エンジニアリング・ケミストリー４８巻，第８号，第１３４２〜１３４６頁，１９５６年、「不織布の基礎と応用」日本繊維機械学会不織布研究会編、社団法人、日本繊維機械学会平成５年８月２５日発行第１１９頁〜第１２７頁など参照）。
この様にメルトブロー法では、紡糸口金から溶融繊維が押出され、それを高温高速の気体を噴射させて、押出された繊維状の溶融ポリマーの流れに吹き当て、その高速気流の作用によって押出された繊維状の溶融ポリマーをけん引して極細繊維流とするので、溶融状態で引き伸ばされるため、一般に延伸による配向はしていない、いわゆる実質的に無延伸の繊維からなる不織布と言える。また、高温高速の気流により、溶融状態の繊維が引きちぎられるので、通常は極細の短繊維からなる不織布とすることができる。
高温高速の気体としては通常空気が用いられるが、スチームその他、溶融状態のポリマーと反応して劣化させるような恐れのない気体であれば他の気体も使用し得る。気体の温度は溶融押出しされるポリマーの種類によっても異なるが、３００〜４００℃であり、気体の圧力は例えば１〜５ｋｇ／ｃｍ2程度が使用されるのが一般的であるが、この条件の範囲内に限定されるものではない。
上記メルトブロー不織布に使用しうる熱可塑性繊維の構成ポリマー成分としては、好ましくはポリオレフィン系ポリマー、ポリエステル系ポリマーが挙げられる。例えば、ポリオレフィン系ポリマーには、ポリプロピレン、高密度ポリエチレン、線状低密度ポリエチレン、エチレン／プロピレン二元共重合体、エチレン／ブテン−１／プロピレン三元共重合体等、ポリエステル系ポリマーには、ポリエチレンテレフタレート、ポリブチレンテレフタレート等が挙げられる。また、これらから構成される熱可塑性繊維に本発明の効果を阻害しない範囲で、顔料、難燃剤、消臭剤、帯電防止剤、酸化防止剤等を添加してもよい。
メルトブロー不織布を構成する繊維としては、単一成分からなる単一繊維、低融点ポリマー成分と高融点ポリマー成分を複合させた複合繊維、低融点ポリマー繊維と高融点ポリマー繊維が混繊された混繊繊維のいずれでもよい。複合繊維からなる不織布、混繊繊維からなる不織布とする場合は、その低融点ポリマー成分と高融点ポリマー成分との融点差は１５℃以上であることが、熱風循環方式で不織布化する場合、低融点ポリマー成分の繊維のみならず、高融点ポリマー成分の繊維までもが軟化ないし溶融し、繊維形状を失いやすく、不織布がフイルム化し、風合を悪化させる恐れがなく好ましい。そしてこの様な複合繊維からなる不織布、または、混繊繊維からなる不織布とすることにより、毛羽立ちの少ない吸収性物品の液体非透過性シートを提供できるので好ましい。そして、単一成分からなる単一繊維を用いるよりも、上述のような複合繊維あるいは混繊繊維から構成する方が他に接着剤などを特に使用せずに、熱接着により容易に繊維間の接着を行って、不織布の強度を向上させる事ができ好ましい。
本発明で用いるメルトブロー不織布の平均繊維径は、通常１０μｍ以下が好ましく、より好ましくは、０．１〜９μｍ、更により好ましくは０．２〜８μｍである。繊維径１０μｍ〜０．１μｍのものが、風合いが優れ、製造も容易で、価格も高くならず好ましい。
本発明に用いるメルトブロー不織布の見かけ密度ｄ（ｇ／ｃｃ）は、０．０５≦ｄ≦０．２である。メルトブロー不織布の見かけ密度ｄが０．０５未満の場合は、メルトブロー不織布の密度が不均一となるため高目付けにしても吸収性物品の液体非透過性シートに必要な液非透過性が保持できず液漏れしてしまう。メルトブロー不織布の見かけ密度ｄが０．２を超える場合は、液非透過性は充分保持できるが、通気性が悪く、圧密化されているために風合いと外観が悪くなり吸収性物品の液体非透過性シートには適さない。
また本発明に用いるメルトブロー不織布の目付けは４〜５０ｇ／ｍ2が好ましく、より好ましくは４〜３０ｇ／ｍ2である。あまりに目付けが小さすぎて、液非透過性が悪くなりこれを保持しようとするため繊維径を細くしなければならず高コストとなると言う問題もなく、またあまりに目付けが大きすぎて、厚みが大きくなり風合いが悪化し、吸収性物品の液体非透過性シートには不向きになると言う問題も生じることがなく、上記の範囲の目付の不織布が好ましく用いられる。
本発明に用いるメルトブロー不織布は、Ｗ：目付ｇ／ｍ2、Ｄ：繊維径μｍとした場合、２≦Ｗ／Ｄ2≦２００を満たす必要がある。
前記式はメルトブロー不織布を構成する繊維の繊維径が細いと不織布目付けは薄くても使用でき、反対に繊維径が太いと不織布目付けは厚いものが必要となることを示す式である。本発明のメルトブロー不織布が上記関係を満たさない場合は、不織布の見かけ密度ｄが０．０５≦ｄ≦０．２の範囲であっても通気性と液非透過性を満足するメルトブロー不織布は得られない。
本発明に用いるメルトブロー不織布は、紡糸捕集後の未加工のものを用いてもいいが、不織布の見かけ密度を管理するために平滑ロールによって圧密化しても良い。この時の平滑ロールは、メルトブロー不織布がフィルム化しない程度の温度に加熱した平滑ロールで処理しても良いが非加熱の平滑ロールでも構わない。
また、繊維間の接着のためにエンボスロール熱接着法、超音波溶着法や低融点ポリマー成分の融点以上で高融点成分の融点未満の熱風を利用した熱風循環法などを利用しても構わない。
本発明に用いるメルトブロー不織布は、不織布強力補強、毛羽立ち防止、肌触り改良等の点から他の各種の熱可塑性繊維不織布と積層して使用しても構わない。積層する他の熱可塑性繊維不織布は、短繊維、長繊維のいずれからなるものでもよい。
積層に使用する熱可塑性繊維不織布が短繊維から構成される場合には、カード法不織布、エアーレイド法不織布等のいずれでも構わない。短繊維不織布を構成している短繊維としては、一成分からなる繊維であってよいし、二成分以上、例えば、三若しくは四成分からなる複合繊維であってもよい。しかし、経済性を考慮すれば、特殊な用途を除いて低融点ポリマーと高融点ポリマーとを複合化させた二成分複合繊維で十分である。
上記短繊維からなる熱可塑性繊維不織布に使用しうる構成ポリマー成分としては、好ましくはポリオレフィン系ポリマー、ポリエステル系ポリマー、ポリアミド系ポリマーなどが挙げられる。例えば、ポリオレフィン系ポリマーには、ポリプロピレン、高密度ポリエチレン、線状低密度ポリエチレン、エチレン／プロピレン二元共重合体、エチレン／ブテン−１／プロピレン三元共重合体等、ポリエステル系ポリマーには、ポリエチレンテレフタレート、ポリブチレンテレフタレート等、ポリアミド系ポリマーには、ナイロン６、ナイロン６６等が挙げられる。また、これらから構成される短繊維に本発明の効果を阻害しない範囲で、顔料、難燃剤、消臭剤、帯電防止剤、酸化防止剤等を添加してもよい。
上記積層に使用する短繊維不織布を構成する前記短繊維として複合繊維を採用する場合には、該複合繊維の高融点ポリマー成分と低融点ポリマー成分との融点差は、１５℃以上が好ましい。また、かかる複合短繊維としては、芯鞘型、偏心鞘芯型、並列型、多層型、海島型の複合繊維が使用できる。
前記積層に使用する短繊維不織布を構成する短繊維の断面形状は、円形断面形状を有するもの、あるいは多角形、偏平形、星形など種々の異形断面形状を有するものであてもよい。また、中空断面形状であってもよい。また、これらの繊維の混繊タイプでもよい。
また、前記積層用の短繊維不織布を構成する繊維の繊度は、特に限定するものではないが０．５〜１０ｄ／ｆが好ましい。短繊維の繊度が余りに小さ過ぎると、短繊維が開繊される際に、開繊機の針が通り難くなり、いわゆるネップが存在する不均質な短繊維不織布となる傾向にある。また、余りに短繊維の繊度が大き過ぎると、短繊維の剛性が高くなって、柔軟性に富む短繊維不織布が得られにくくなる傾向になる。短繊維は、繊維長が３〜５１ｍｍ程度が嵩高性、開繊性、均質性などのバランスの取れた不織布が得られ望ましい。
更に、かかる短繊維としては、捲縮が付与されたものおよび非捲縮のものが使用できる。とりわけ、嵩高性が良好な点において、短繊維は螺旋型、ジグザグ型、Ｕ字型等の捲縮が付与されたものが好ましい。
本発明に用いるメルトブロー不織布と積層用の短繊維不織布を積層させるには、例えばエンボスロールによる熱接着法、その他超音波溶着法や低融点ポリマー成分の融点以上で高融点ポリマー成分の融点未満の熱風を利用した熱風循環法、ホットメルトポリマーを使用したホットメルト法などが使用できる。
本発明のメルトブロー不織布との積層に短繊維不織布を用いると、通気性と液非透過性を阻害せず、風合いが良好であり、嵩高性に優れ柔軟性に富んだ吸収性物品に用いられる液体非透過性シートを提供できる。
本発明のメルトブロー不織布と積層される熱可塑性繊維不織布が長繊維からなる熱可塑性繊維不織布の場合、長繊維不織布を構成している長繊維としては、一成分からなる繊維であってよいし、二成分以上、例えば、三若しくは四成分からなる複合繊維であってもよい。しかし、複合繊維の場合、経済性を考慮すれば、特殊な用途を除いて低融点ポリマーと高融点ポリマーとを複合化させた二成分複合繊維で十分である。
上記積層用の長繊維不織布に使用しうる構成ポリマー成分としては、好ましくはポリオレフィン系ポリマー、ポリエステル系ポリマー、ポリアミド系ポリマーなどが挙げられる。例えば、ポリオレフィン系ポリマーには、ポリプロピレン、高密度ポリエチレン、線状低密度ポリエチレン、エチレン／プロピレン二元共重合体、エチレン／ブテン−１／プロピレン三元共重合体等、ポリエステル系ポリマーには、ポリエチレンテレフタレート、ポリブチレンテレフタレート等、ポリアミド系ポリマーには、ナイロン６、ナイロン６６等が挙げられる。また、これらから構成される短繊維に本発明の効果を阻害しない範囲で、顔料、難燃剤、消臭剤、帯電防止剤、酸化防止剤等を添加してもよい。
上記積層用の長繊維不織布を構成する繊維として複合繊維を用いる場合には、該複合繊維の高融点ポリマー成分と低融点ポリマー成分との融点差は、１５℃以上が好ましい。
また、該複合長繊維は、芯鞘型、偏心鞘芯型、並列型、多層型、海島型の複合繊維が使用できる。
上記長繊維の断面形状は、円形断面形状を有するもの、あるいは多角形、偏平形、星形など種々の異形断面形状を有するものであってもよい。また、中空断面形状であってもよい。また、これらの繊維の混繊型タイプでもよい。
本発明において積層用に使用する長繊維不織布を製造するには、特に限定するものではないが、いわゆるスパンボンド法が好適に適用できる。
具体的には、例えばポリマーを押出機に投入し、紡糸口金を用いて溶融紡糸する。紡糸口金より吐出した繊維群をエアーサッカーに導入して牽引延伸し、長繊維群を得、続いて、エアーサッカーより排出された長繊維群を、コロナ放電装置などの適宜の帯電装置によりに同電荷を付与せしめ帯電させた後、一対の振動する羽根状物（フラップ）の間を通過させることで開繊させ、或いは適宜の反射板などに衝突させて開繊し、開繊された長繊維群は裏面に吸引装置を設けた捕集用無端ネット状コンベアー上に、長繊維フリースとして堆積する。
また、上記の様なスパンボンド法以外でも、通常の溶融紡糸により得られる収束されたトウを開繊し不織布化したものも用いることができる。
また、この長繊維不織布を製造する際、１５℃以上の融点差がある低融点ポリマー成分と高融点ポリマー成分とで構成される複合繊維を用いてもよい。複合繊維を用いる場合、構成する各成分のポリマーをそれぞれ個別の押出機に投入し、複合紡糸口金を用いて溶融紡糸する。
又、さらに、長繊維不織布を、１５℃以上の融点差がある低融点ポリマー成分からなる長繊維と高融点ポリマー成分からなる長繊維とからなる混繊繊維で構成してもよい。
本発明に用いる積層用の長繊維不織布の繊度は特別な限定はないが、０．５〜１０ｄ／ｆが好ましい。あまりに繊度が小さすぎると、コストが高くなり、あまりに繊度が大きすぎると、風合いが低下する傾向がある。
本発明に用いるメルトブロー不織布と長繊維不織布を積層させるには、例えばエンボスロールによる熱接着法、その他超音波溶着法や低融点ポリマー成分の融点以上で高融点ポリマー成分の融点未満の熱風を利用した熱風循環法、ホットメルトポリマーを使用したホットメルト法などが使用できる。
本発明のメルトブロー不織布との積層に長繊維不織布を用いると、毛羽立ちが少なく、通気性と液非透過性を阻害せず、風合いが良好であり、柔軟性に富み、高不織布強力となるため特に好ましい形態となる吸収性物品の液体非透過性シートを提供できる。
以下図面を用いて、吸収性物品の本発明による液体非透過性シートが、吸収性物品のどの様な部分に使用されるかその代表例を挙げて説明するが、図示した吸収性物品の構造は一例であって、吸収性物品がこの図示した構造のもののみに限定されると言う意味ではない。本発明の液体非透過性シートは、各種の吸収性物品の液体非透過性シートまたは撥水性シートが用いられている部分に用いることができ、吸収性物品全体の構造が特定の構造のものに限定されるものではない。
図１は紙おむつの一例の肌側から見た展開平面図であり、図２はそのＸ−Ｘ´部分の断面の概略端面図、図３はそのＹ−Ｙ´部分の断面の概略端面図である。
図１〜３において、１は体液を吸収し保持するための液体吸収層であり、特に限定するものではないが、例えばフラッフパルプなどのセルロース系繊維、高吸水性ポリマーからなる樹脂、必要に応じ合成繊維の混合物などからなっている。そして液体吸収層１は、必要に応じてティッシュペーパーなどに包み込まれていてもよい。２はその表面側（肌に接する側）に配置される例えば不織布、織布または編布などからなる液体透過性の表カバーである。そして３は液体非透過性が要求されるバックシートである。ラウンドシート４は必ずしも必要ではないが、図２、図３においては液体吸収層１とバックシート３との間に設けられている例を図示している。そして５、５´が前述した様に吸収性物品が身体の動きによって所定の着用状態から位置がずれたり、横向きに寝転んだりした場合に、吸収した体液などの液体が漏れるのを防止するために吸収性物品の両脇に液体非透過性シートからなるサイドシート（紙おむつなどの場合にはギャザーが付与されている場合が多いのでサイドギャザーとかレッグカフなどとも言われており、紙おむつの場合には、サイドシートは紙おむつを着用した場合に太もものつけね又は太ももを回って太ももを把持する様な位置に設けられている。）である。そして特に図２、図３では図示していないが、図１の７、７´として示したウェスト位置の肌側に帯状にウェストギャザーなどが設けられていても良い。これらの各部材は、図面では記載を省略しているが、適宜の部分が接着されていて、脱落しない様になっている。本発明の液体非透過性シートは、この様な吸収性物品のバックシートなど従来より液体非透過性シートが用いられている部分や、サイドシート、ラウンドシートならびにウェストギャザーなどの従来より撥水性シートが用いられている部分の少なくとも１つに用いることにより、通気性が良好で、かつ液非透過性を保持し、風合いの良好な吸収性物品の１種である紙おむつを提供することができる。特にかかる吸収性物品のバックシートに用いると、比較的カバーする面積が大きいし、バックシートとして必要な十分な液非透過性を有し、かつ通気性、風合いも良好なので、効果的である。
次に図４に生理用ナプキンの一例の肌側から見た展開平面図を示し、また、図５にそのＸ−Ｘ´部分の断面の概略端面図を示した。１が液体吸収層、２がその表面側（肌に接する側）に配置される例えばメッシュシート、不織布、織布または編布などからなる液体透過性の表カバー、３が液体非透過性が要求されるバックシートである。そして５、５´がサイドシートである。これらの各部材は、図面では記載を省略しているが、適宜の部分が接着されていて、脱落しない様になっている。本発明の液体非透過性シートは、この生理用ナプキンのバックシートまたはサイドシートなどの少なくとも１つに用いることにより、通気性が良好で、かつ液非透過性を保持し、風合いの良好な吸収性物品の１種である生理用ナプキンを提供することができる。特に生理用ナプキンの場合には、通気性が良好で、かつ液非透過性を保持し、風合いの良好な本発明の液体非透過性シートを少なくともそのバックシートに用いると、比較的カバーする面積が大きいので、効果的である。
実施例
以下実施例により本発明を具体的に説明するが、本発明はこれらの実施例のみに限定されるものではない。
尚、以下に述べる実施例中における各種の物性値は以下の方法で測定されたものである。
［繊維径］：
メルトブロー不織布について、その位置に関しては特に限定しないが約１ｃｍ×１ｃｍの小片を１０個切り取り、前記小片１個あたり１箇所を走査型電子顕微鏡で倍率１００〜５０００倍の写真を撮り、計１００本の繊維直径を測定し、平均値を繊維径（単位μｍ）とした。
［不織布強力］：
引っ張り強度試験機（島津製作所製オートグラフＡＧ−５００Ｄ）を用い、５ｃｍ幅の不織布の縦方向破断強力および横方向の破断強力（ｋｇ／５ｃｍ）を求め、５個の平均値をとり、（縦方向破断強度×横方向破断強度）1/2の式に代入し計算した。かくして得られたデータを目付け×５ｃｍで割った値を不織布強力とした（単位ｋｇ／ｃｍ（ｇ／ｍ2））。
［不織布の見かけ密度］：
メルトブロー不織布の１ｍ2当たりの重量を出し、メルトブロー不織布の厚みを走査型電子顕微鏡にて測定し１ｃｃ当たりの重量を不織布の見かけ密度とした（単位ｇ／ｃｃ）。
［通気度］：
通気性試験機（東洋精機製作所製）を用い、５個の平均値をとった。ＪＩＳＬ１００４，１０１８に基づく（単位ｃｃ／ｃｍ2／秒）。
［耐水圧］：
耐水圧測定器（東洋精機製作所製）を用い、５個の平均値をとった（単位ｍｍ）。
（実施例１）
ポリプロピレンを３３０℃で溶融し押出機から３００℃に加熱された円断面の紡糸口金に供給し、溶融紡糸し、紡糸口金より押出されたポリマーを温度３５０℃、ガス圧３．２ｋｇ／ｃｍ2の高温・高速の空気流でブローし、捕集無端ネット状コンベアー上にメルトブロー不織布のウェッブを堆積させ、１２０℃に加熱した平滑ロール同士で構成された圧密加工機に通してメルトブロー不織布のウェッブを得た。
次いで得られたウェッブを１３０℃に加熱させた凹凸ロールと平滑ロールとで構成されたポイントボンド加工機の加圧されたロール間に通し部分的に繊維間を熱接着させた。
得られた上記メルトブロー不織布は、繊維径Ｄが１．５μｍ、目付けＷが２７ｇ／ｍ2のもので、不織布見かけ密度ｄ（表に於ては単に不織布密度と略記している。）が０．０９ｇ／ｃｃとなりかつ前記式（Ａ）の値（表１に於てはＡ式値と表現した）は１２であった。
前記メルトブロー不織布は、風合、柔軟性、通気性が良好でかつ耐水圧を保持する吸収性物品に用いられる液体非透過性シートに適する不織布であった。条件は表１に、結果は表２に示した。
また、前記液体非透過性シートを図１〜５に示した様な吸収性物品、すなわち紙おむつならびに生理用ナプキンのバックシートに用いて着用評価した。その結果、体液の吸収性物品外への漏れもなく、通気性が良好でかつ風合も好評であった。
（実施例２）
繊維径Ｄが１．０μｍ、及びＡ式値は２７であった以外は全て実施例１と同様にしてメルトブロー不織布を得た。
前記メルトブロー不織布は、風合、柔軟性、通気性が良好でかつ耐水圧を保持する吸収性物品に用いられる液体非透過性シートに適する不織布であった。条件は表１に、結果は表２に示した。
また、前記液体非透過性シートを図１〜５に示した様な吸収性物品、すなわち紙おむつならびに生理用ナプキンのバックシートに用いて着用評価した。その結果、体液の吸収性物品外への漏れもなく、通気性が良好でかつ風合も好評であった。
（実施例３）
不織布密度が０．０８ｇ／ｃｃ、目付けＷが１０ｇ／ｍ2となりかつＡ式値は４．４であった以外は全て実施例１と同様にしてメルトブロー不織布を得た。
実施例１と同様にして繊維径Ｄが１．０μｍ、目付けＷが１０ｇ／ｍ2のメルトブローウェッブを得た。
積層させる別の熱可塑性繊維不織布として、ポリプロピレンを３００℃で溶融し押出機から、ポリエチレンを２２０℃で溶融しもう一つの押出機から、２８０℃に加熱された鞘芯型の複合紡糸口金に供給し、芯成分がポリプロピレン、鞘成分がポリエチレンとなるように溶融紡糸し、スパンボンド法により、紡糸された鞘芯型の複合繊維をエアーサッカーに通し、２５００ｍ／分の速度で引取り、帯電装置により強制的に帯電させて繊維を開繊し、捕集コンベアー上に堆積させた長繊維フリースを作成し、上記メルトブロー不織布のウェッブへ該長繊維フリースを積層した
次いで得られた積層物を１２８℃に加熱させた凹凸ロールと平滑ロールとで構成されたポイントボンド加工機の加圧されたロール間に通し部分的に繊維間を熱接着させた。
積層後のメルトブロー不織布の部分は、不織布見かけ密度ｄが０．０８ｇ／ｃｃとなりかつＡ式値は４．４であった。
前記メルトブロー積層不織布は、風合、柔軟性、通気性が良好でかつ耐水圧を保持する吸収性物品に用いられる液体非透過性シートに適する不織布であった。不織布強力も、長繊維不織布を積層させることによって強いものが得られた。条件は表１に、結果は表２に示した。
また、前記積層不織布からなる液体非透過性シートを図１〜５に示した様な吸収性物品、すなわち紙おむつならびに生理用ナプキンのバックシートに用いて着用評価した。その結果、体液の吸収性物品外への漏れもなく、通気性が良好でかつ風合も好評であった。
（実施例４）
ポリエチレンを２２０℃で溶融し押出機から、ポリプロピレンを３３０℃で溶融しもう一つの押出機から３００℃に加熱された混繊型の紡糸口金に供給し、溶融紡糸し、紡糸口金より押出されたポリマーを温度３５０℃、ガス圧３ｋｇ／ｃｍ2の高温・高速の空気流でブローし、捕集無端ネット状コンベアー上にメルトブロー不織布のウェッブを堆積させて、実施例１と同様にして圧密加工し、繊維径Ｄが１．５μｍ、目付けＷが１０ｇ／ｍ2のメルトブロー不織布のウェッブを得た。
積層させる熱可塑性繊維不織布を実施例３と同様にして得た。
次いで上記メルトブロー不織布へ該長繊維フリースを積層し、得られた積層物を１２６℃に加熱させた凹凸ロールと平滑ロールとで構成されたポイントボンド加工機の加圧されたロール間に通し部分的に繊維間を熱接着させた。
積層後のメルトブロー不織布の部分は、不織布見かけ密度ｄが０．０８ｇ／ｃｃとなりかつＡ式値は４．４であった。
前記メルトブロー積層不織布は、毛羽立ちが少なく、風合、柔軟性、通気性が良好でかつ耐水圧を保持する吸収性物品に用いられる液体非透過性シートに適する不織布であった。不織布強力も、長繊維不織布を積層させることによって強いものが得られた。条件は表１に、結果は表２に示した。
また、前記積層不織布からなる液体非透過性シートを図１〜５に示した様な吸収性物品、すなわち紙おむつならびに生理用ナプキンのバックシートに用いて着用評価した。その結果、体液の吸収性物品外への漏れもなく、通気性が良好でかつ風合も好評であった。
（実施例５）
プロピレン−エチレン−ブテン−１三元共重合体（エチレン成分の共重合割合は２．５重量％、ブテン−１の共重合割合は４．５重量％である。表１ではこの三元共重合体をＣＯＰＰと表示した。）を２５０℃で溶融し押出機から、ポリプロピレンを３３０℃で溶融しもう一つの押出機から３００℃に加熱された鞘芯型の紡糸口金に供給し、鞘芯型複合繊維（鞘成分：プロピレン−エチレン−ブテン−１三元共重合体、芯成分：ポリプロピレン）に溶融紡糸し、紡糸口金より押出されたポリマーを温度３５０℃、ガス圧３ｋｇ／ｃｍ2の高温・高速の気流でブローし、捕集無端ネット状コンベアー上にメルトブロー不織布のウェッブを堆積させて、実施例１と同様に圧密処理し、繊維径Ｄが１．５μｍ、目付けＷが１０ｇ／ｍ2のメルトブロー不織布のウェッブを得た。
積層させる熱可塑性繊維不織布として低融点成分としてポリエチレンの代わりに前記と同様のプロピレン−エチレン−ブテン−１三元共重合体を２４０℃で押し出した以外は実施例３と同様にして複合繊維の長繊維フリースを得た。
次いで上記メルトブロー不織布へ該長繊維フリースを積層し、得られた積層物を１２８℃に加熱させた凹凸ロールと平滑ロールとで構成されたポイントボンド加工機の加圧されたロール間に通し部分的に繊維間を熱接着させた。
積層後のメルトブロー不織布の部分は、不織布見かけ密度ｄが０．０８ｇ／ｃｃとなりかつＡ式値は４．４であった。
前記メルトブロー積層不織布は、毛羽立ちが少なく、風合、柔軟性、通気性が良好でかつ耐水圧を保持する吸収性物品に用いられる液体非透過性シートに適する不織布であった。不織布強力も、長繊維不織布を積層させることによって強いものが得られた。条件は表１に、結果は表２に示した。
また、前記積層不織布からなる液体非透過性シートを図１〜５に示した様な吸収性物品、すなわち紙おむつならびに生理用ナプキンのサイドシートならびにバックシートに用いて着用評価した。その結果、体液の吸収性物品外への漏れもなく、通気性が良好でかつ風合も好評であった。
（実施例６）
ポリエチレンを２２０℃で溶融し押出機から、ポリプロピレンを３３０℃で溶融しもう一つの押出機から３００℃に加熱された並列型の紡糸口金に供給し、溶融紡糸し、紡糸口金より押出されたポリマーを温度３５０℃、ガス圧３．２ｋｇ／ｃｍ2の高温・高速の空気流でブローし、捕集無端ネット状コンベアー上にメルトブロー不織布のウェッブを堆積させて、実施例１と同様にして圧密処理し、繊維径Ｄが１．５μｍ、目付けＷが１０ｇ／ｍ2のメルトブロー不織布のウェッブを得た。
積層させる熱可塑性繊維不織布としては、ポリプロピレンを３００℃で溶融し押出機から、ポリエチレンを２２０℃で溶融しもう一つの押出機から２８０℃に加熱された偏心鞘芯型の複合紡糸口金に供給し、溶融紡糸し、紡糸された偏心鞘芯型繊維（鞘成分：ポリエチレン、芯成分ポリプロピレン）を一旦ボビンに巻き取り、１００℃の延伸ロールを用い４．０倍に延伸し、スタッファボックス型クリンパーでジグザグ型捲縮を付与して、２．５ｄ／ｆの繊維を得た。該繊維を長さ３８ｍｍに切断し、カード機を通し、短繊維不織布のウェッブを作成した。
次いで上記メルトブロー不織布へ該短繊維不織布のウェッブを積層し、得られた積層物を１２６℃に加熱させた凹凸ロールと平滑ロールとで構成されたポイントボンド加工機の加圧されたロール間に通し部分的に繊維間を熱接着させた。
積層後のメルトブロー不織布の部分は、不織布見かけ密度ｄが０．０８ｇ／ｃｃとなりかつＡ式値は４．４であった。
前記メルトブロー積層不織布は、風合、柔軟性、通気性が良好でかつ耐水圧を保持する吸収性物品に用いられる液体非透過性シートに適する不織布であった。不織布強力も、短繊維不織布を積層させることによって強いものが得られた。条件は表１に、結果は表２に示した。
また、前記積層不織布からなる液体非透過性シートを図１〜３に示した様な吸収性物品、すなわち紙おむつのラウンドシートならびにバックシートに用いて着用評価した。その結果、体液の吸収性物品外への漏れもなく、通気性が良好でかつ風合も好評であった。
（実施例７）
メルトブロー不織布のウェッブは、混繊型の紡糸口金を用いた以外は全て実施例５と同様にしてメルトブロー不織布ウェッブを得た。すなわちポリプロピレン極細繊維とプロピレン−エチレン−ブテン−１三元共重合体極細繊維との混繊繊維から構成されるメルトブロー不織布ウェッブを得た。
積層させる熱可塑性繊維不織布として偏心鞘芯型の紡糸口金を用いた以外は全て実施例５と同様にして偏心鞘芯型複合長繊維フリース（鞘成分：プロピレン−エチレン−ブテン−１三元共重合体、芯成分：ポリプロピレン）を得た。
次いで上記メルトブロー不織布へ該長繊維フリースを積層し、得られた積層物を１２８℃に加熱させた凹凸ロールと平滑ロールとで構成されたポイントボンド加工機の加圧されたロール間に通し部分的に繊維間を熱接着させた。
積層後のメルトブロー不織布の部分は、不織布見かけ密度ｄが０．０８ｇ／ｃｃとなりかつＡ式値は４．４であった。
前記メルトブロー積層不織布は、毛羽立ちが少なく、風合、柔軟性、通気性が良好でかつ耐水圧を保持する吸収性物品に用いられる液体非透過性シートに適する不織布であった。不織布強力も、長繊維不織布を積層させることによって強いものが得られた。条件は表１に、結果は表２に示した。
また、前記積層不織布からなる液体非透過性シートを図１〜５に示した様な吸収性物品、すなわち紙おむつならびに生理用ナプキンのサイドシートならびにバックシートに用いて着用評価した。その結果、体液の吸収性物品外への漏れもなく、通気性が良好でかつ風合も好評であった。
（比較例１）
メルトブロー不織布のウェッブは、目付けＷを２０ｇ／ｍ2とし、圧密加工を行わなかった以外は実施例１と同様にして得た。
得られたメルトブロー不織布のウェッブを１３０℃に加熱させた凹凸ロールと平滑ロールとで構成されたポイントボンド加工機の加圧されたロール間に通し部分的に繊維間を熱接着させた。
上記の如くして得られたメルトブロー不織布は、Ａ式値は９であったが、不織布見かけ密度ｄが０．０３ｇ／ｃｃと低かった。
前記メルトブロー積層不織布は、通気性が良好であるが、耐水圧を保持することができず吸収性物品に用いられる液体非透過性シートに適する不織布ではなかった。条件は表１に、結果は表２に示した。
また、前記液体非透過性シートを図１〜５に示した様な吸収性物品、すなわち紙おむつならびに生理用ナプキンのバックシートに用いて着用評価した。その結果、通気性と風合は良好であったが、体液の吸収性物品外への漏れが発生し、不評であった。
（比較例２）
メルトブロー不織布の目付を４ｇ／ｍ2とした以外は実施例７と同様にしてメルトブロー不織布を製造し、また、メルトブロー不織布のウェッブと積層させる熱可塑性繊維不織布も実施例７と同様にして長繊維フリースを得た。
次いで上記メルトブロー不織布へ該長繊維フリースを積層し、得られた積層物を１２８℃に加熱させた凹凸ロールと平滑ロールとで構成されたポイントボンド加工機の加圧されたロール間に通し部分的に繊維間を熱接着させた。
積層後のメルトブロー不織布は、不織布見かけ密度ｄが０．０９ｇ／ｃｃであったがＡ式値は１．８であった。
前記メルトブロー積層不織布は、通気性は良好であるが、耐水圧を保持することができず、吸収性物品に用いられる液体非透過性シートに適する不織布ではなかった。条件は表１に、結果は表２に示した。
また、前記積層不織布からなる液体非透過性シートを図１〜５に示した様な吸収性物品、すなわち紙おむつならびに生理用ナプキンのバックシートに用いて着用評価した。その結果、通気性と風合は良好であったが、体液の吸収性物品外への漏れが発生し、不評であった。
（比較例３）
ポリエチレンを２２０℃で溶融し押出機から、ポリプロピレンを３３０℃で溶融しもう一つの押出機から３００℃に加熱された並列型の複合紡糸口金に供給し、溶融紡糸し、紡糸口金より押出されたポリマーを温度３５０℃、ガス圧２．８ｋｇ／ｃｍ2の高温・高速の空気流でブローし、捕集無端ネット状コンベアー上にメルトブロー不織布のウェッブを堆積させて、実施例１と同様にして圧密加工し、繊維径Ｄが２．０μｍ、目付けＷが７ｇ／ｍ2のメルトブロー不織布のウェッブを得た。
積層させる熱可塑性繊維不織布として、ポリプロピレンを３００℃で溶融し押出機から、ポリエチレンを２２０℃で溶融しもう一つの押出機から、２８０℃に加熱された偏心鞘芯型の複合紡糸口金に供給し、芯成分がポリプロピレン、鞘成分がポリエチレンとなるように溶融紡糸し、紡糸された偏心鞘芯型複合繊維を一旦ボビンに巻き取り、１００℃の延伸ロールを用い４．０倍に延伸し、スタッファボックス型クリンパーでジグザグ型捲縮を付与して、２．５ｄ／ｆの繊維を得た。該繊維を長さ３８ｍｍに切断し、カード機を通し、短繊維不織布のウェッブを作成した。
次いで上記メルトブロー不織布へ該短繊維不織布のウェッブを積層し、得られた積層物を１２６℃に加熱させた凹凸ロールと平滑ロールとで構成されたポイントボンド加工機の加圧されたロール間に通し部分的に繊維間を熱接着させた。
積層後のメルトブロー不織布の部分の不織布見かけ密度ｄは０．１ｇ／ｃｃであったが、Ａ式値は１．８であった。
前記メルトブロー積層不織布は、通気性は良好であるが、耐水圧を保持することができず、吸収性物品に用いられる液体非透過性シートに適する不織布ではなかった。条件は表１に、結果は表２に示した。
また、前記積層不織布からなる液体非透過性シートを図１〜５に示した様な吸収性物品、すなわち紙おむつならびに生理用ナプキンのバックシートに用いて着用評価した。その結果、通気性と風合は良好であったが、体液の吸収性物品外への漏れが発生し、不評であった。

Figure 0004442932
Figure 0004442932
Technical field
The present invention relates to a liquid-impermeable sheet for absorbent articles such as disposable diapers and sanitary napkins for medical hygiene materials, and absorbent articles using the same. More particularly, the present invention relates to a liquid non-permeable sheet for absorbent articles having good air permeability and texture, and liquid non-permeable, and an absorbent article using part of the liquid non-permeable sheet. is there.
Background art
Conventionally, absorbent articles such as disposable diapers and sanitary napkins for medical hygiene materials absorb at least a body fluid such as urine and blood to prevent leakage, and at least a liquid absorption layer that absorbs and retains body fluid such as urine and blood A liquid-permeable front cover made of non-woven fabric, woven fabric or knitted fabric, for example, which is arranged on the surface side (side in contact with the skin) and a back side surface which prevents the absorbed body fluid from leaking to the outside A liquid non-permeable back sheet for the purpose. In addition, in an absorbent article such as a paper diaper or a sanitary napkin, in addition to the backsheet, the absorbent article is displaced from a predetermined wearing state due to movement of the body, or lies down sideways. Side sheets made of water-repellent sheets on both sides of the absorbent article to prevent leakage of fluids such as absorbed body fluids (in the case of paper diapers, etc., gathers are often added, so side gathers or leg cuffs, etc. In the case of a disposable diaper, the side sheet is provided at a position where the thigh is worn or the thigh is gripped when the disposable diaper is worn. In the case of disposable diapers, liquids such as absorbed body fluid are transferred to the skin side of the part that covers the abdomen and the upper part of the buttocks on the opposite side. There is also a water-repellent round sheet, etc., to prevent it from leaking out of the water-absorbent article if it leaks to the upper part of the abdomen or buttocks due to the movement of the wearer such as dripping, lying down, rotating the body etc. Yes. Further, in the case of a paper diaper or the like, some belts are provided with a waist gather on the waist side skin side, and these are also formed of a water-repellent sheet.
As the liquid absorbing layer, various appropriate liquid absorbing layers made of a cellulose fiber such as fluff pulp, a super absorbent polymer, and a mixture of synthetic fibers as required are used.
In general, the back sheets of these absorbent articles are liquid non-permeable sheets that are required to have a relatively large liquid impermeability, and the side sheets, round sheets, waist gathers, etc. A sheet having water repellency is used, although it does not have such a liquid impermeability.
Conventionally, a thermoplastic film has been used as a back sheet for these absorbent articles. The thermoplastic film generally has innumerable fine holes in order to prevent internal stuffiness during wearing, and is generally breathable. In addition, a composite with a non-woven fabric is used from the viewpoint of improving the plastic feel and appearance unique to the film and improving the strength. Further, non-woven fabrics having water repellency and the like are used for side sheets, round sheets and waist gathers.
In this way, there are portions where liquid non-permeable sheets and water repellent sheets are used as components of absorbent articles.
As described above, a thermoplastic film with air permeability is generally used for the back sheet of the absorbent article, but the liquid impervious property and the air permeability are required to be contradictory. It is still insufficient from the viewpoint of a satisfactory backsheet. That is, when a thermoplastic film is used, the liquid impermeability is satisfactory, but the air permeability is not sufficient. The material used for side sheets, round sheets, and waist gathers is made of non-woven fabric with water repellency as described above. However, liquid impermeability is further reduced without sacrificing air permeability. It is more preferable if the property can be imparted.
In Japanese Patent No. 2533253 (JP-A-4-226658), a liquid non-permeable baffle layer is provided between the absorber and the back sheet made of a plastic film in order to prevent liquid leakage and maintain a cloth-like texture. However, it becomes a complicated structure and the weight increases.
In JP-A-6-14949, a liquid-impervious sheet is provided between the absorber and the plastic film, but it is still insufficient.
An object of the present invention is to provide a liquid non-permeable sheet for absorbent articles having good air permeability and liquid impermeability and having a good texture, and an absorbent article using the same. Another object of the present invention is to provide a liquid non-permeable sheet for absorbent articles that has the above-mentioned excellent properties and is even more powerful and an absorbent article using the same.
Disclosure of the invention
In order to achieve the above object, the liquid non-permeable sheet for absorbent articles of the present invention comprises:A liquid non-permeable sheet for absorbent articles in which a fiber nonwoven fabric made of a thermoplastic polymer is laminated to a melt blown nonwoven fabric, the fiber nonwoven fabric made of the thermoplastic polymer is a long fiber nonwoven fabric produced by a spunbond method, The melt blown nonwoven fabric has a fiber diameter of 10 μm or less composed of a low melting polymer ultrafine fiber and a high melting polymer ultrafine fiber having a melting point difference of 15 ° C. or higher, which is spun by a melt blow method using a mixed fiber spinneret. It is a blend of thermoplastic ultrafine fibers, a meltblown nonwoven fabric that is unprocessed after spinning collection or is consolidated by a smooth roll,The melt blown nonwoven fabric satisfies the following formulas A and B.
2 ≦ W / D2≦ 200 ・ ・ ・ ・ (A)
0.05 ≦ d ≦ 0.2 (B)
W: basis weight g / m2
D: Fiber diameter μm
d: Apparent density of nonwoven fabric g / cc
Moreover, in the sheet | seat of the said invention, it is preferable that a liquid impermeable sheet | seat is at least 1 sort (s) chosen from the back sheet, side sheet, round sheet, and waist gathers of an absorbent article.
In the sheet of the present invention, the meltblown nonwoven fabric is preferably at least one polymer selected from polyolefin and polyester..
Moreover, in the said sheet | seat of this invention, it is preferable that the average fiber diameter of a melt blown nonwoven fabric is the range of 0.1-9 micrometers.
In the sheet of the present invention, the basis weight of the meltblown nonwoven fabric is preferably in the range of 4 to 50 g / m2..
In the sheet of the present invention, the thermoplastic fiber nonwoven fabric is preferably a two-component composite fiber in which a low melting point polymer and a high melting point polymer are combined.
In the sheet of the present invention, the melting point difference between the high melting point polymer component and the low melting point polymer component of the composite fiber is preferably 15 ° C. or more.
In the sheet of the present invention, the composite fiber is preferably at least one fiber selected from a core-sheath type, an eccentric sheath-core type, a parallel type, a multilayer type, and a sea-island type composite fiber.
In the sheet of the present invention, the polymer component constituting the composite fiber is preferably at least one polymer selected from polyolefin-based, polyester-based and polyamide-based materials..
Moreover, in the sheet | seat of the said invention, it is preferable that the cross-sectional shape of the fiber which comprises a nonwoven fabric is at least 1 shape chosen from a circular cross section, a deformed cross section, and a hollow cross-sectional shape.
Further, in the sheet of the present invention, the lamination of the melt blown nonwoven fabric and the fiber nonwoven fabric for lamination is heat bonding with an embossing roll, ultrasonic welding, hot air having a temperature higher than the melting point of the low melting polymer component and lower than the melting point of the high melting polymer component. Lamination by at least one adhesion selected from hot air circulation adhesion using hot melt and hot melt adhesion using hot melt polymer is preferable.
Next, the absorbent article of the present invention is characterized in that the liquid impermeable sheet of the present invention is partially used.
The nonwoven fabric constituting the liquid-impermeable sheet for absorbent articles of the present invention is a thermoplastic ultrafine fiber nonwoven fabric having a fiber diameter of 10 μm or less spun by the melt blow method, and the nonwoven fabric comprises the formula (A), ( By satisfying the formula (B), it is possible to provide a liquid non-permeable sheet that can be used for an absorbent article having good air permeability and liquid impermeability, and having excellent texture and flexibility.
Furthermore, by adopting a preferred embodiment of the present invention using a laminate of the melt blown nonwoven fabric and another thermoplastic fiber nonwoven fabric, a liquid impermeability suitable for absorbent articles having strong nonwoven fabric strength and good texture. Can provide a sheet.
Moreover, the melt blown nonwoven fabric is a preferred embodiment of the present invention in which the nonwoven fabric is composed of a thermoplastic ultrafine composite fiber having a fiber diameter of 10 μm or less in which a low melting point polymer having a melting point difference of 15 ° C. or more and a high melting point polymer are combined. Thus, it is possible to provide a liquid-impermeable sheet that is suitably used for absorbent articles with less fuzz.
Further, the present invention provides a melt blown nonwoven fabric as a nonwoven fabric made of a mixture of thermoplastic ultrafine fibers having a fiber diameter of 10 μm or less, consisting of ultrafine fibers of a low melting point polymer having a melting point difference of 15 ° C. or more and ultrafine fibers of a high melting point polymer. By setting it as the preferable aspect of this, the liquid impermeable sheet | seat used suitably for an absorbent article with few fuzzing can be provided.
Further, by making the thermoplastic fiber nonwoven fabric laminated with the melt blown nonwoven fabric a preferred embodiment of the present invention in which the nonwoven fabric is a long fiber nonwoven fabric, a liquid impermeable sheet suitably used for absorbent articles with less fuzz and strong nonwoven fabric Can be provided.
In addition, when the liquid impermeable sheet is at least one selected from a back sheet, a side sheet, a round sheet, and a waist gather of an absorbent article, the air permeability is good and the liquid non-permeability is set. It is suitably used for producing an absorbent article that exhibits the effect of maintaining permeability effectively and has excellent texture and flexibility.
Further, the absorbent article of the present invention using the liquid impermeable sheet as a part is an absorbent article having good air permeability and good feeling without leakage of body fluid to the outside of the absorbent article. Can be provided.
[Brief description of the drawings]
FIG. 1 is a developed plan view of an example of a paper diaper using a liquid impermeable sheet of the present invention as a part thereof, as viewed from the skin side.
FIG. 2 is a schematic end view of a cross section taken along the line XX ′ of FIG.
FIG. 3 is a schematic end view of a cross section of the YY ′ portion of FIG. 1.
FIG. 4 is a developed plan view of an example of a sanitary napkin using part of the liquid impermeable sheet of the present invention as viewed from the skin side.
FIG. 5 is a schematic end view of a cross section taken along the line XX ′ of FIG.
BEST MODE FOR CARRYING OUT THE INVENTION
The nonwoven fabric used for the liquid-impermeable sheet of the absorbent article of the present invention is a nonwoven fabric spun by a melt blow method.
Melt blown nonwoven fabrics are well known and will not be described in detail. However, melt-extruded thermoplastic polymer is used to extrude the melted polymer from the melt-blow spinneret into fibers, and at the same time, slits are provided around the spinning orifice. A high-temperature and high-speed gas is jetted from and blown to the extruded fibrous molten polymer stream. The fibrous molten polymer extruded by the action of the high-speed air current is pulled to form an ultrafine fiber stream, which is deposited on a collecting device such as an endless net-type conveyor for collection to form an ultrafine fiber web. It is made into a non-woven fabric by applying a treatment. (Japanese Laid-Open Patent Publication No. 1-156561, Industrial and Engineering Chemistry Vol. 48, No. 8, pp. 1342-1346, 1956, “Fundamentals and Applications of Non-woven Fabrics” edited by the Japan Textile Machinery Society Non-woven Fabric Study Group, incorporated association (See, for example, pages 119 to 127 published on August 25, 1993).
As described above, in the melt blow method, the molten fiber is extruded from the spinneret, and a high-temperature and high-speed gas is jetted and sprayed on the flow of the extruded fibrous molten polymer. Since the fibrous molten polymer is drawn to form an ultrafine fiber stream, it is stretched in a molten state. Therefore, it can be said to be a nonwoven fabric composed of so-called substantially unstretched fibers that are not generally oriented by stretching. Moreover, since the melted fiber is torn off by the high-temperature and high-speed airflow, it is usually possible to form a nonwoven fabric composed of ultrafine short fibers.
Air is usually used as the high-temperature and high-speed gas, but other gases may be used as long as they do not have the risk of being deteriorated by reacting with the polymer in the molten state. The gas temperature varies depending on the type of polymer to be melt-extruded, but is 300 to 400 ° C., and the gas pressure is, for example, 1 to 5 kg / cm.2The degree is generally used, but is not limited to this range of conditions.
The constituent polymer component of the thermoplastic fiber that can be used in the melt blown nonwoven fabric is preferably a polyolefin polymer or a polyester polymer. For example, for polyolefin polymers, polypropylene, high density polyethylene, linear low density polyethylene, ethylene / propylene binary copolymer, ethylene / butene-1 / propylene terpolymer, etc., for polyester polymers, polyethylene Examples include terephthalate and polybutylene terephthalate. In addition, pigments, flame retardants, deodorants, antistatic agents, antioxidants, and the like may be added to the thermoplastic fibers composed of these as long as the effects of the present invention are not impaired.
The fibers constituting the melt blown nonwoven fabric include single fibers composed of a single component, composite fibers in which a low-melting polymer component and a high-melting polymer component are combined, and mixed fibers in which a low-melting polymer fiber and a high-melting polymer fiber are mixed. Any of the fibers may be used. In the case of a nonwoven fabric made of a composite fiber and a nonwoven fabric made of a mixed fiber, the melting point difference between the low melting point polymer component and the high melting point polymer component is 15 ° C. or more. Not only the fibers of the melting point polymer component but also the fibers of the high melting point polymer component are softened or melted, the fiber shape tends to be lost, the nonwoven fabric is filmed, and the feeling is not deteriorated. And it is preferable to use a nonwoven fabric made of such a composite fiber or a nonwoven fabric made of mixed fiber because a liquid-impermeable sheet of an absorbent article with less fluff can be provided. And, rather than using a single fiber composed of a single component, it is easier to use a composite fiber or a mixed fiber as described above without using an adhesive or the like. Adhesion is preferable because the strength of the nonwoven fabric can be improved.
The average fiber diameter of the melt blown nonwoven fabric used in the present invention is usually preferably 10 μm or less, more preferably 0.1 to 9 μm, and still more preferably 0.2 to 8 μm. A fiber having a fiber diameter of 10 μm to 0.1 μm is preferable because it has an excellent texture, is easy to manufacture, and does not increase the price.
The apparent density d (g / cc) of the melt blown nonwoven fabric used in the present invention is 0.05 ≦ d ≦ 0.2. When the apparent density d of the melt blown nonwoven fabric is less than 0.05, the density of the melt blown nonwoven fabric becomes non-uniform, so that the liquid impermeability necessary for the liquid impervious sheet of the absorbent article cannot be maintained even with high weight. Liquid leaks. When the apparent density d of the melt blown nonwoven fabric exceeds 0.2, the liquid impermeability can be sufficiently maintained, but the air permeability is poor and the compaction makes the texture and the appearance worse and the liquid impermeability of the absorbent article. Not suitable for sex sheets.
The basis weight of the melt blown nonwoven fabric used in the present invention is 4 to 50 g / m.2Is more preferable, and 4 to 30 g / m is more preferable.2It is. There is no problem that the fabric weight is too small, the liquid impermeability becomes worse and the fiber diameter has to be reduced in order to maintain this, and there is no problem that the cost is high, and the fabric weight is too large and the thickness is large. There is no problem that the texture becomes worse and it is not suitable for the liquid-impermeable sheet of the absorbent article, and a non-woven fabric having a weight per unit area is preferably used.
The melt blown nonwoven fabric used in the present invention has W: basis weight g / m.2, D: When the fiber diameter is μm, 2 ≦ W / D2It is necessary to satisfy ≦ 200.
The above expression is an expression indicating that if the fiber diameter of the fibers constituting the melt blown nonwoven fabric is thin, the nonwoven fabric can be used even if the fabric weight is thin. Conversely, if the fiber diameter is large, the nonwoven fabric basis weight needs to be thick. When the melt blown nonwoven fabric of the present invention does not satisfy the above relationship, a melt blown nonwoven fabric satisfying air permeability and liquid impermeability can be obtained even if the apparent density d of the nonwoven fabric is in the range of 0.05 ≦ d ≦ 0.2. Absent.
The melt-blown nonwoven fabric used in the present invention may be an unprocessed one after spinning collection, but may be consolidated with a smooth roll in order to manage the apparent density of the nonwoven fabric. The smooth roll at this time may be treated with a smooth roll heated to a temperature at which the melt-blown nonwoven fabric is not formed into a film, but may be a non-heated smooth roll.
In addition, for bonding between fibers, an embossing roll thermal bonding method, an ultrasonic welding method, a hot air circulation method using hot air that is higher than the melting point of the low melting point polymer component and lower than the melting point of the high melting point component may be used. .
The melt blown nonwoven fabric used in the present invention may be used by laminating with various other thermoplastic fiber nonwoven fabrics from the viewpoint of strong reinforcement of the nonwoven fabric, prevention of fluffing, improvement of touch, and the like. The other thermoplastic fiber nonwoven fabric to be laminated may be composed of either short fibers or long fibers.
When the thermoplastic fiber nonwoven fabric used for lamination is composed of short fibers, any of card method nonwoven fabric, air laid method nonwoven fabric and the like may be used. The short fiber constituting the short fiber nonwoven fabric may be a fiber composed of one component, or a composite fiber composed of two or more components, for example, three or four components. However, in consideration of economic efficiency, a bicomponent composite fiber in which a low melting point polymer and a high melting point polymer are combined is sufficient except for special applications.
The constituent polymer component that can be used for the thermoplastic fiber nonwoven fabric composed of the above short fibers is preferably a polyolefin-based polymer, a polyester-based polymer, a polyamide-based polymer, or the like. For example, for polyolefin polymers, polypropylene, high density polyethylene, linear low density polyethylene, ethylene / propylene binary copolymer, ethylene / butene-1 / propylene terpolymer, etc., for polyester polymers, polyethylene Examples of polyamide polymers such as terephthalate and polybutylene terephthalate include nylon 6 and nylon 66. In addition, pigments, flame retardants, deodorants, antistatic agents, antioxidants, and the like may be added to the short fibers composed of these as long as the effects of the present invention are not impaired.
When a composite fiber is employed as the short fiber constituting the short fiber nonwoven fabric used for the lamination, the difference in melting point between the high melting point polymer component and the low melting point polymer component of the composite fiber is preferably 15 ° C. or higher. In addition, as the composite short fiber, a core-sheath type, an eccentric sheath-core type, a parallel type, a multilayer type, and a sea-island type composite fiber can be used.
The cross-sectional shape of the short fibers constituting the short-fiber nonwoven fabric used for the lamination may be one having a circular cross-sectional shape, or various irregular cross-sectional shapes such as polygons, flat shapes, and star shapes. Moreover, a hollow cross-sectional shape may be sufficient. Further, a mixed fiber type of these fibers may be used.
Moreover, the fineness of the fiber which comprises the said short fiber nonwoven fabric for lamination | stacking is although it does not specifically limit, 0.5-10 d / f is preferable. If the fineness of the short fibers is too small, when the short fibers are opened, it becomes difficult for the needles of the spreader to pass through, and there is a tendency to become a non-homogeneous short fiber nonwoven fabric in which a so-called nep is present. On the other hand, if the fineness of the short fiber is too large, the rigidity of the short fiber becomes high, and it becomes difficult to obtain a short fiber nonwoven fabric rich in flexibility. A short fiber having a fiber length of about 3 to 51 mm is desirable because a nonwoven fabric having a good balance of bulkiness, spreadability, and homogeneity can be obtained.
Furthermore, as such short fibers, those with crimps and those without crimps can be used. In particular, in terms of good bulkiness, the short fibers are preferably provided with crimps such as a spiral type, a zigzag type, and a U shape.
In order to laminate the melt blown nonwoven fabric used for the present invention and the short fiber nonwoven fabric for lamination, for example, heat bonding using an embossing roll, other ultrasonic welding methods, hot air having a melting point higher than the melting point of the low melting polymer component and lower than the melting point of the high melting polymer component A hot air circulation method using a hot melt method or a hot melt method using a hot melt polymer can be used.
When a short fiber nonwoven fabric is used for laminating with the melt blown nonwoven fabric of the present invention, the liquid used for the absorbent article which does not inhibit air permeability and liquid impermeability, has a good texture, is excellent in bulkiness and is rich in flexibility. An impermeable sheet can be provided.
In the case where the thermoplastic fiber nonwoven fabric laminated with the melt blown nonwoven fabric of the present invention is a thermoplastic fiber nonwoven fabric composed of long fibers, the long fibers constituting the long fiber nonwoven fabric may be one-component fibers, or two It may be a composite fiber composed of more than one component, for example, three or four components. However, in the case of a composite fiber, considering economic efficiency, a bicomponent composite fiber in which a low melting point polymer and a high melting point polymer are combined is sufficient except for special applications.
As the constituent polymer component that can be used for the above-mentioned laminated long-fiber nonwoven fabric, polyolefin polymers, polyester polymers, polyamide polymers, and the like are preferable. For example, for polyolefin polymers, polypropylene, high density polyethylene, linear low density polyethylene, ethylene / propylene binary copolymer, ethylene / butene-1 / propylene terpolymer, etc., for polyester polymers, polyethylene Examples of polyamide polymers such as terephthalate and polybutylene terephthalate include nylon 6 and nylon 66. In addition, pigments, flame retardants, deodorants, antistatic agents, antioxidants, and the like may be added to the short fibers composed of these as long as the effects of the present invention are not impaired.
When a composite fiber is used as the fiber constituting the long-fiber nonwoven fabric for lamination, the melting point difference between the high-melting polymer component and the low-melting polymer component of the composite fiber is preferably 15 ° C. or higher.
The composite long fiber may be a core-sheath type, an eccentric sheath-core type, a parallel type, a multilayer type, or a sea-island type composite fiber.
The cross-sectional shape of the long fibers may have a circular cross-sectional shape, or various irregular cross-sectional shapes such as a polygonal shape, a flat shape, and a star shape. Moreover, a hollow cross-sectional shape may be sufficient. Further, a mixed fiber type of these fibers may be used.
Although it does not specifically limit in order to manufacture the long-fiber nonwoven fabric used for lamination | stacking in this invention, The so-called spunbond method can be applied suitably.
Specifically, for example, a polymer is put into an extruder and melt-spun using a spinneret. The fiber group discharged from the spinneret is introduced into the air soccer ball and pulled and drawn to obtain a long fiber group, and then the long fiber group discharged from the air soccer ball is mixed with an appropriate charging device such as a corona discharge device. After being charged and charged, it is opened by passing it between a pair of vibrating blades (flaps), or it is opened by colliding with an appropriate reflector etc. The group is deposited as a long fiber fleece on an endless net conveyor for collection with a suction device on the back.
In addition to the spunbond method as described above, a non-woven fabric obtained by opening a converged tow obtained by normal melt spinning can be used.
Moreover, when manufacturing this long-fiber nonwoven fabric, you may use the composite fiber comprised by the low melting-point polymer component with a melting | fusing point difference of 15 degreeC or more, and a high melting-point polymer component. When using a composite fiber, each constituent polymer is put into an individual extruder and melt-spun using a composite spinneret.
Further, the long fiber nonwoven fabric may be composed of a mixed fiber composed of long fibers made of a low melting point polymer component having a melting point difference of 15 ° C. or more and long fibers made of a high melting point polymer component.
The fineness of the non-woven fabric for lamination used in the present invention is not particularly limited, but is preferably 0.5 to 10 d / f. If the fineness is too small, the cost becomes high, and if the fineness is too large, the texture tends to decrease.
In order to laminate the melt blown nonwoven fabric and the long fiber nonwoven fabric used in the present invention, for example, a heat bonding method using an embossing roll, other ultrasonic welding methods, or hot air that is higher than the melting point of the low melting polymer component and lower than the melting point of the high melting polymer component was used. A hot air circulation method, a hot melt method using a hot melt polymer, or the like can be used.
When a long-fiber nonwoven fabric is used for laminating with the melt blown nonwoven fabric of the present invention, there is less fuzzing, air permeability and liquid impermeability are not hindered, texture is good, flexibility is high, and high nonwoven fabric strength is particularly strong. A liquid-impermeable sheet of an absorbent article that is in a preferred form can be provided.
Hereinafter, with reference to the drawings, a part of the absorbent article in which the liquid-impermeable sheet according to the present invention is used will be described with reference to typical examples. Is an example and does not mean that the absorbent article is limited to the illustrated structure. The liquid-impermeable sheet of the present invention can be used in a portion of various absorbent articles where the liquid-impermeable sheet or water-repellent sheet is used, and the entire structure of the absorbent article has a specific structure. It is not limited.
FIG. 1 is a developed plan view of an example of a paper diaper as viewed from the skin side, FIG. 2 is a schematic end view of the cross section of the XX ′ portion, and FIG. 3 is a schematic end view of the cross section of the YY ′ portion. is there.
1-3, 1 is a liquid absorption layer for absorbing and holding bodily fluids, and is not particularly limited. For example, cellulosic fibers such as fluff pulp, a resin composed of a superabsorbent polymer, and as necessary. It consists of a mixture of synthetic fibers. And the liquid absorption layer 1 may be wrapped in the tissue paper etc. as needed. Reference numeral 2 denotes a liquid-permeable front cover made of, for example, a nonwoven fabric, a woven fabric, or a knitted fabric, which is disposed on the surface side (the side in contact with the skin). Reference numeral 3 denotes a back sheet that requires liquid impermeability. Although the round sheet 4 is not necessarily required, FIGS. 2 and 3 show examples provided between the liquid absorbing layer 1 and the back sheet 3. In order to prevent liquids such as absorbed body fluid from leaking when the absorbent article is displaced from a predetermined wearing state or lies down sideways due to movement of the body as described above in 5 and 5 '. Side sheets made of liquid-impermeable sheets on both sides of the absorbent article (in the case of paper diapers, gathers are often given, so they are also called side gathers or leg cuffs. In the case of paper diapers, The side sheet is provided in such a position that when a paper diaper is worn, the thigh is worn or the thigh is held around the thigh. Although not particularly shown in FIGS. 2 and 3, a waist gather or the like may be provided in a band shape on the skin side of the waist position indicated as 7 or 7 'in FIG. Although these members are not shown in the drawings, appropriate portions are adhered so that they do not fall off. The liquid impervious sheet of the present invention is a part that conventionally uses a liquid impermeable sheet such as a back sheet of such an absorbent article, a side sheet, a round sheet, a waist repellent sheet such as a waist gather, and the like. By using it for at least one of the portions where the diaper is used, it is possible to provide a paper diaper which is one type of absorbent article having good air permeability and liquid impermeability and good texture. In particular, it is effective when used in the back sheet of such an absorbent article because it has a relatively large area to cover, has sufficient liquid impermeability necessary for the back sheet, and has good air permeability and texture.
Next, FIG. 4 shows a developed plan view of an example of a sanitary napkin viewed from the skin side, and FIG. 5 shows a schematic end view of a cross section of the XX ′ portion. 1 is a liquid-absorbing layer, 2 is disposed on the surface side (side in contact with the skin), for example, a liquid-permeable front cover made of mesh sheet, non-woven fabric, woven fabric or knitted fabric, and 3 is required to be liquid-impermeable Back sheet. 5 and 5 'are side sheets. Although these members are not shown in the drawings, appropriate portions are bonded so that they do not fall off. The liquid impervious sheet of the present invention is used for at least one of the sanitary napkin backsheet or side sheet, etc., so that the air permeability is good and the liquid impermeability is maintained, and the texture is absorbed well. A sanitary napkin which is a kind of sex goods can be provided. In particular, in the case of sanitary napkins, when the liquid non-permeable sheet of the present invention having good air permeability and liquid impermeability and good texture is used for at least the back sheet, a relatively covering area. Is effective.
Example
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited only to these examples.
Incidentally, various physical property values in Examples described below were measured by the following methods.
[Fiber diameter]:
Regarding the melt blown nonwoven fabric, the position is not particularly limited, but 10 pieces of about 1 cm × 1 cm are cut out, and one place per piece is taken with a scanning electron microscope at a magnification of 100 to 5000 times, for a total of 100 pieces. The fiber diameter was measured, and the average value was defined as the fiber diameter (unit: μm).
[Non-woven fabric]:
Using a tensile strength tester (manufactured by Shimadzu Autograph AG-500D), the longitudinal breaking strength and the transverse breaking strength (kg / 5 cm) of a nonwoven fabric with a width of 5 cm were obtained, and the average value of five pieces was taken. Direction breaking strength x transverse direction breaking strength)1/2Substituting into the formula of The value obtained by dividing the data thus obtained by the basis weight × 5 cm was regarded as the strength of the nonwoven fabric (unit: kg / cm (g / m2)).
[Apparent density of non-woven fabric]:
1m of melt blown nonwoven fabric2The weight per hit was measured, the thickness of the meltblown nonwoven fabric was measured with a scanning electron microscope, and the weight per 1 cc was taken as the apparent density of the nonwoven fabric (unit: g / cc).
[Air permeability]:
Using an air permeability tester (manufactured by Toyo Seiki Seisakusho), an average value of 5 was taken. Based on JISL 1004, 1018 (unit: cc / cm2/ Sec).
[Water pressure resistance]:
Using a water pressure resistance measuring instrument (manufactured by Toyo Seiki Seisakusho), an average value of 5 was taken (unit: mm).
Example 1
A polypropylene melted at 330 ° C. and supplied from an extruder to a spinneret having a circular cross section heated to 300 ° C., melt-spun, and the polymer extruded from the spinneret was 350 ° C. at a gas pressure of 3.2 kg / cm.2The web of melt blown nonwoven fabric is blown with a high-temperature and high-speed air flow, and the web of melt blown nonwoven fabric is deposited on a collection endless net-shaped conveyor, and the melt blown nonwoven web is passed through a compacting machine composed of smooth rolls heated to 120 ° C. Obtained.
Next, the obtained web was partially heat-bonded between the fibers through a pressed roll of a point bond processing machine composed of an uneven roll heated to 130 ° C. and a smooth roll.
The obtained melt blown nonwoven fabric has a fiber diameter D of 1.5 μm and a basis weight W of 27 g / m.2The apparent density d of the nonwoven fabric (simply abbreviated as “nonwoven fabric density” in the table) is 0.09 g / cc, and the value of the above formula (A) (in Table 1, (Expressed) was 12.
The melt blown non-woven fabric was a non-woven fabric suitable for a liquid-impermeable sheet used for an absorbent article having good texture, flexibility and air permeability and maintaining a water pressure resistance. The conditions are shown in Table 1, and the results are shown in Table 2.
Further, the liquid impermeable sheet was used for evaluation as an absorbent article as shown in FIGS. 1 to 5, that is, a paper diaper and a sanitary napkin backsheet. As a result, there was no leakage of body fluid to the outside of the absorbent article, the air permeability was good, and the texture was also popular.
(Example 2)
A melt blown nonwoven fabric was obtained in the same manner as in Example 1 except that the fiber diameter D was 1.0 μm and the value of the formula A was 27.
The melt blown non-woven fabric was a non-woven fabric suitable for a liquid-impermeable sheet used for an absorbent article having good texture, flexibility and air permeability and maintaining a water pressure resistance. The conditions are shown in Table 1, and the results are shown in Table 2.
Further, the liquid impermeable sheet was used for evaluation as an absorbent article as shown in FIGS. 1 to 5, that is, a paper diaper and a sanitary napkin backsheet. As a result, there was no leakage of body fluid to the outside of the absorbent article, the air permeability was good, and the texture was also popular.
(Example 3)
Nonwoven fabric density is 0.08 g / cc, basis weight W is 10 g / m2The melt blown nonwoven fabric was obtained in the same manner as in Example 1 except that the value of Formula A was 4.4.
In the same manner as in Example 1, the fiber diameter D is 1.0 μm, and the basis weight W is 10 g / m.2The melt blow web was obtained.
As another thermoplastic fiber nonwoven fabric to be laminated, polypropylene is melted at 300 ° C. and fed from an extruder, polyethylene is melted at 220 ° C. and fed from another extruder to a sheath-core type composite spinneret heated to 280 ° C. Then, melt spinning is performed so that the core component is polypropylene and the sheath component is polyethylene, and the spun-bonded composite fiber of the sheath-core type is passed through an air soccer ball by a spunbond method and taken up at a speed of 2500 m / min. The fibers were forcibly charged by the fiber to open the fibers, and the long fiber fleece deposited on the collecting conveyor was created, and the long fiber fleece was laminated on the melt blown nonwoven web.
Next, the obtained laminate was thermally bonded between the fibers partially through a pressurized roll of a point bond processing machine composed of an uneven roll and a smooth roll heated to 128 ° C.
The melt blown nonwoven fabric portion after lamination had a nonwoven fabric apparent density d of 0.08 g / cc and an A-type value of 4.4.
The melt blown laminated nonwoven fabric was a nonwoven fabric suitable for a liquid-impermeable sheet used for an absorbent article having good texture, flexibility, and air permeability and maintaining water pressure resistance. A strong non-woven fabric was also obtained by laminating long-fiber non-woven fabrics. The conditions are shown in Table 1, and the results are shown in Table 2.
Moreover, the liquid impermeable sheet which consists of the said laminated nonwoven fabric was used for the absorbent article as shown in FIGS. 1-5, ie, a paper diaper, and the sanitary napkin back sheet, and evaluated wearing. As a result, there was no leakage of body fluid to the outside of the absorbent article, the air permeability was good, and the texture was also popular.
Example 4
Polyethylene was melted at 220 ° C. and extruded from an extruder, and polypropylene was melted at 330 ° C. and supplied to a mixed fiber type spinneret heated to 300 ° C., melt-spun, and extruded from the spinneret. Polymer temperature 350 ° C, gas pressure 3kg / cm2Blowing with a high-temperature, high-speed air flow, depositing a web of melt-blown nonwoven fabric on a collecting endless net-shaped conveyor, and compacting the same as in Example 1, with a fiber diameter D of 1.5 μm and a basis weight of W 10 g / m2A melt blown nonwoven web was obtained.
A thermoplastic fiber nonwoven fabric to be laminated was obtained in the same manner as in Example 3.
Next, the long fiber fleece is laminated on the melt blown nonwoven fabric, and the obtained laminate is partially passed between the pressurized rolls of a point bond processing machine composed of an uneven roll and a smooth roll heated to 126 ° C. The fibers were thermally bonded to each other.
The melt blown nonwoven fabric portion after lamination had a nonwoven fabric apparent density d of 0.08 g / cc and an A-type value of 4.4.
The melt blown laminated nonwoven fabric is a nonwoven fabric suitable for a liquid-impermeable sheet used for absorbent articles that have less fuzz, good texture, flexibility, and air permeability and retains water pressure resistance. A strong non-woven fabric was also obtained by laminating long-fiber non-woven fabrics. The conditions are shown in Table 1, and the results are shown in Table 2.
Moreover, the liquid impermeable sheet which consists of the said laminated nonwoven fabric was worn and evaluated using the absorbent article as shown in FIGS. 1-5, ie, a paper diaper, and the back sheet | seat of a sanitary napkin. As a result, there was no leakage of body fluid to the outside of the absorbent article, the air permeability was good, and the texture was also popular.
(Example 5)
Propylene-ethylene-butene-1 terpolymer (the copolymerization ratio of the ethylene component is 2.5% by weight and the copolymerization ratio of butene-1 is 4.5% by weight. The coalescence was indicated as COPP.) Was melted at 250 ° C. and fed from an extruder, polypropylene was melted at 330 ° C. and heated to 300 ° C. from another extruder, and fed to a sheath core type spinneret. Polymer spun into a composite fiber (sheath component: propylene-ethylene-butene-1 terpolymer, core component: polypropylene) and extruded from the spinneret at a temperature of 350 ° C. and a gas pressure of 3 kg / cm2The web is blown with a high-temperature, high-speed air flow, and a web of melt-blown nonwoven fabric is deposited on a collection endless net-shaped conveyor, and compacted in the same manner as in Example 1. The fiber diameter D is 1.5 μm, and the basis weight W is 10 g / m2A melt blown nonwoven web was obtained.
The length of the composite fiber in the same manner as in Example 3 except that the same thermoplastic propylene-ethylene-butene-1 terpolymer as described above was extruded at 240 ° C. instead of polyethylene as a low melting point component as the thermoplastic nonwoven fabric to be laminated. A fiber fleece was obtained.
Next, the long fiber fleece is laminated on the melt blown nonwoven fabric, and the obtained laminate is partially passed between the pressurized rolls of a point bond processing machine composed of an uneven roll and a smooth roll heated to 128 ° C. The fibers were thermally bonded to each other.
The melt blown nonwoven fabric portion after lamination had a nonwoven fabric apparent density d of 0.08 g / cc and an A-type value of 4.4.
The melt blown laminated nonwoven fabric is a nonwoven fabric suitable for a liquid-impermeable sheet used for absorbent articles that have less fuzz, good texture, flexibility, and air permeability and retains water pressure resistance. A strong non-woven fabric was also obtained by laminating long-fiber non-woven fabrics. The conditions are shown in Table 1, and the results are shown in Table 2.
The liquid non-permeable sheet made of the laminated nonwoven fabric was worn and evaluated using absorbent articles as shown in FIGS. 1 to 5, that is, a paper diaper, a side sheet and a back sheet of a sanitary napkin. As a result, there was no leakage of body fluid to the outside of the absorbent article, the air permeability was good, and the texture was also popular.
(Example 6)
Polymer melted at 220 ° C., extruded from an extruder, polypropylene melted at 330 ° C., and fed from another extruder to a parallel spinneret heated to 300 ° C., melt spun, and extruded from the spinneret Temperature 350 ° C., gas pressure 3.2 kg / cm2The web is blown with a high-temperature, high-speed air flow, and a web of melt-blown nonwoven fabric is deposited on the collecting endless net-shaped conveyor, and is compacted in the same manner as in Example 1. The fiber diameter D is 1.5 μm and the basis weight W is 10 g / m2A melt blown nonwoven web was obtained.
As the thermoplastic fiber nonwoven fabric to be laminated, polypropylene is melted at 300 ° C. and fed from an extruder, and polyethylene is melted at 220 ° C. and heated to 280 ° C., and then supplied to an eccentric sheath core type composite spinneret. The melt-spun and spun eccentric sheath-core fiber (sheath component: polyethylene, core component polypropylene) is once wound around a bobbin and stretched 4.0 times using a 100 ° C stretching roll, and a stuffer box type crimper To give a 2.5 d / f fiber. The fiber was cut into a length of 38 mm, and passed through a card machine to prepare a web of a short fiber nonwoven fabric.
Next, the web of the short fiber nonwoven fabric is laminated on the melt blown nonwoven fabric, and the obtained laminate is passed through a pressurized roll of a point bond processing machine composed of an uneven roll heated to 126 ° C. and a smooth roll. The fibers were partially thermally bonded.
The melt blown nonwoven fabric portion after lamination had a nonwoven fabric apparent density d of 0.08 g / cc and an A-type value of 4.4.
The melt blown laminated nonwoven fabric was a nonwoven fabric suitable for a liquid-impermeable sheet used for an absorbent article having good texture, flexibility, and air permeability and maintaining water pressure resistance. A strong non-woven fabric was also obtained by laminating short-fiber non-woven fabrics. The conditions are shown in Table 1, and the results are shown in Table 2.
Moreover, the liquid impermeable sheet which consists of the said laminated nonwoven fabric was worn and evaluated using the absorbent article as shown in FIGS. 1-3, ie, the round sheet of a paper diaper, and a back sheet. As a result, there was no leakage of body fluid to the outside of the absorbent article, the air permeability was good, and the texture was also popular.
(Example 7)
The melt blown nonwoven web was obtained in the same manner as in Example 5 except that a mixed fiber type spinneret was used. That is, a melt blown nonwoven web composed of mixed fibers of polypropylene ultrafine fibers and propylene-ethylene-butene-1 terpolymer ultrafine fibers was obtained.
Eccentric sheath core type composite long fiber fleece (sheath component: propylene-ethylene-butene-1 ternary co-polymer) was carried out in the same manner as in Example 5 except that an eccentric sheath core type spinneret was used as the thermoplastic nonwoven fabric to be laminated. Combined, core component: polypropylene) was obtained.
Next, the long fiber fleece is laminated on the melt blown nonwoven fabric, and the obtained laminate is partially passed between the pressurized rolls of a point bond processing machine composed of an uneven roll and a smooth roll heated to 128 ° C. The fibers were thermally bonded to each other.
The melt blown nonwoven fabric portion after lamination had a nonwoven fabric apparent density d of 0.08 g / cc and an A-type value of 4.4.
The melt blown laminated nonwoven fabric is a nonwoven fabric suitable for a liquid-impermeable sheet used for absorbent articles that have less fuzz, good texture, flexibility, and air permeability and retains water pressure resistance. A strong non-woven fabric was also obtained by laminating long-fiber non-woven fabrics. The conditions are shown in Table 1, and the results are shown in Table 2.
The liquid non-permeable sheet made of the laminated nonwoven fabric was worn and evaluated using absorbent articles as shown in FIGS. 1 to 5, that is, a paper diaper, a side sheet and a back sheet of a sanitary napkin. As a result, there was no leakage of body fluid to the outside of the absorbent article, the air permeability was good, and the texture was also popular.
(Comparative Example 1)
The web of melt blown nonwoven fabric has a weight per unit area of 20 g / m.2And obtained in the same manner as in Example 1 except that the compacting was not performed.
The obtained melt-blown nonwoven web was partially and thermally bonded between the fibers through a pressurized roll of a point bond processing machine composed of a concavo-convex roll heated to 130 ° C. and a smooth roll.
The meltblown nonwoven fabric obtained as described above had an A-type value of 9, but the nonwoven fabric apparent density d was as low as 0.03 g / cc.
The melt blown laminated nonwoven fabric has good air permeability but cannot maintain a water pressure resistance, and is not a nonwoven fabric suitable for a liquid impermeable sheet used for absorbent articles. The conditions are shown in Table 1, and the results are shown in Table 2.
Further, the liquid impermeable sheet was used for evaluation as an absorbent article as shown in FIGS. 1 to 5, that is, a paper diaper and a sanitary napkin backsheet. As a result, the air permeability and texture were good, but the body fluid leaked out of the absorbent article, which was unpopular.
(Comparative Example 2)
The basis weight of the melt blown nonwoven fabric is 4 g / m2A melt blown nonwoven fabric was produced in the same manner as in Example 7 except that a thermoplastic fiber nonwoven fabric laminated with a web of melt blown nonwoven fabric was obtained in the same manner as in Example 7 to obtain a long fiber fleece.
Next, the long fiber fleece is laminated on the melt blown nonwoven fabric, and the obtained laminate is partially passed between the pressurized rolls of a point bond processing machine composed of an uneven roll and a smooth roll heated to 128 ° C. The fibers were thermally bonded to each other.
The melt blown nonwoven fabric after lamination had a nonwoven fabric apparent density d of 0.09 g / cc but an A-type value of 1.8.
The melt blown laminated nonwoven fabric has good air permeability but cannot maintain water pressure resistance, and is not a nonwoven fabric suitable for a liquid-impermeable sheet used for absorbent articles. The conditions are shown in Table 1, and the results are shown in Table 2.
Moreover, the liquid impermeable sheet which consists of the said laminated nonwoven fabric was worn and evaluated using the absorbent article as shown in FIGS. 1-5, ie, a paper diaper, and the back sheet | seat of a sanitary napkin. As a result, the air permeability and texture were good, but the body fluid leaked out of the absorbent article, which was unpopular.
(Comparative Example 3)
Polyethylene was melted at 220 ° C., extruded from an extruder, polypropylene was melted at 330 ° C., and supplied to a parallel-type composite spinneret heated to 300 ° C., melt-spun, and extruded from the spinneret. Polymer temperature is 350 ° C., gas pressure is 2.8 kg / cm2Blowing with a high-temperature, high-speed air flow, depositing a web of melt-blown nonwoven fabric on a collecting endless net-like conveyor, and compacting as in Example 1, with a fiber diameter D of 2.0 μm and a basis weight of W 7g / m2A melt blown nonwoven web was obtained.
As thermoplastic fiber nonwoven fabric to be laminated, polypropylene is melted at 300 ° C. and fed from an extruder, polyethylene is melted at 220 ° C. and fed to an eccentric sheath core type composite spinneret heated to 280 ° C. , Melt-spun so that the core component is polypropylene and the sheath component is polyethylene, the spun eccentric sheath-core composite fiber is once wound on a bobbin, and stretched 4.0 times using a 100 ° C stretching roll, and the staff A zigzag crimp was imparted by a box-type crimper to obtain a fiber of 2.5 d / f. The fiber was cut into a length of 38 mm, and passed through a card machine to prepare a web of a short fiber nonwoven fabric.
Next, the web of the short fiber nonwoven fabric is laminated on the melt blown nonwoven fabric, and the obtained laminate is passed through a pressurized roll of a point bond processing machine composed of an uneven roll heated to 126 ° C. and a smooth roll. The fibers were partially thermally bonded.
Although the apparent density d of the nonwoven fabric in the melt blown nonwoven fabric portion after lamination was 0.1 g / cc, the value of formula A was 1.8.
The melt blown laminated nonwoven fabric has good air permeability but cannot maintain water pressure resistance, and is not a nonwoven fabric suitable for a liquid-impermeable sheet used for absorbent articles. The conditions are shown in Table 1, and the results are shown in Table 2.
Moreover, the liquid impermeable sheet which consists of the said laminated nonwoven fabric was worn and evaluated using the absorbent article as shown in FIGS. 1-5, ie, a paper diaper, and the back sheet | seat of a sanitary napkin. As a result, the air permeability and texture were good, but the body fluid leaked out of the absorbent article, which was unpopular.
Figure 0004442932
Figure 0004442932

Claims (11)

メルトブロー不織布に熱可塑性ポリマーからなる繊維不織布が積層されてなる吸収性物品用液体非透過性シートであり、
前記熱可塑性ポリマーからなる繊維不織布は、スパンボンド法で製造される円形断面の長繊維不織布であり、
前記メルトブロー不織布は、混繊型の紡糸口金を用いてメルトブロー法で紡糸された、融点差が１５℃以上である円形断面の低融点ポリマーの極細繊維と円形断面の高融点ポリマーの極細繊維とからなる繊維径１０μｍ以下の熱可塑性極細繊維の混繊品であり、
紡糸捕集後に未加工であるかまたは平滑ロールによって圧密化されたメルトブロー不織布であり、
前記メルトブロー不織布は、下記Ａ、Ｂ式を満足することを特徴とする吸収性物品用液体非透過性シート。
２≦Ｗ／Ｄ2≦２００・・・・（Ａ）
０．０５≦ｄ≦０．２・・・・（Ｂ）
Ｗ：目付ｇ／ｍ2
Ｄ：繊維径μｍ
ｄ：不織布の見かけ密度ｇ／ｃｃA liquid non-permeable sheet for absorbent articles, in which a fiber nonwoven fabric made of a thermoplastic polymer is laminated on a melt blown nonwoven fabric,
The fiber nonwoven fabric made of the thermoplastic polymer is a long-fiber nonwoven fabric having a circular cross section manufactured by a spunbond method,
The melt blown non-woven fabric is composed of a low-melting polymer ultrafine fiber having a circular cross section having a melting point difference of 15 ° C. or more and a ultrafine fiber having a high melting point polymer having a circular cross section, which is spun by a melt blow method using a mixed fiber type spinneret. A mixture of thermoplastic ultrafine fibers having a fiber diameter of 10 μm or less,
It is a melt blown nonwoven fabric that is raw after spinning collection or consolidated by a smooth roll,
The melt-blown nonwoven fabric satisfies the following formulas A and B: A liquid-impermeable sheet for absorbent articles.
2 ≦ W / D 2 ≦ 200 (A)
0.05 ≦ d ≦ 0.2 (B)
W: basis weight g / m 2
D: Fiber diameter μm
d: Apparent density of nonwoven fabric g / cc 液体非透過性シートが、吸収性物品のバックシート、サイドシート、ラウンドシート及びウェストギャザーから選ばれる少なくとも１種である請求項１に記載の吸収性物品用液体非透過性シート。The liquid impermeable sheet for absorbent articles according to claim 1, wherein the liquid impermeable sheet is at least one selected from a back sheet, a side sheet, a round sheet and a waist gather of the absorbent article. メルトブロー不織布が、ポリオレフィン系及びポリエステル系から選ばれる少なくとも一つのポリマーである請求項１に記載の吸収性物品用液体非透過性シート。The liquid impervious sheet for absorbent articles according to claim 1, wherein the meltblown nonwoven fabric is at least one polymer selected from polyolefin and polyester. メルトブロー不織布の平均繊維径が、０．１〜９μｍの範囲である請求項１に記載の吸収性物品用液体非透過性シート。The liquid impervious sheet for absorbent articles according to claim 1, wherein the melt blown nonwoven fabric has an average fiber diameter in the range of 0.1 to 9 µm. メルトブロー不織布の目付けが、４〜５０ｇ／ｍ2の範囲である請求項１に記載の吸収性物品用液体非透過性シート。The basis weight of the meltblown nonwoven fabric, an absorbent article liquid impermeable sheet according to claim 1 in the range of 4~50g / m 2. 熱可塑性ポリマーからなる繊維不織布が、低融点ポリマーと高融点ポリマーとを複合化させた二成分複合繊維である請求項１に記載の吸収性物品用液体非透過性シート。Nonwoven fabric made of thermoplastic polymer, the absorbent article liquid impermeable sheet according to claim 1 and a low melting point polymer and high melting polymer is a bicomponent conjugate fiber obtained by composite. 複合繊維の高融点ポリマー成分と低融点ポリマー成分との融点差が、１５℃以上である請求項６に記載の吸収性物品用液体非透過性シート。The liquid impervious sheet for absorbent articles according to claim 6, wherein the melting point difference between the high melting point polymer component and the low melting point polymer component of the composite fiber is 15 ° C or more. 複合繊維が、芯鞘型、偏心鞘芯型、並列型、多層型及び海島型の複合繊維から選ばれる少なくとも１つの繊維である請求項６に記載の吸収性物品用液体非透過性シート。The liquid impermeable sheet for absorbent articles according to claim 6, wherein the composite fiber is at least one fiber selected from a core-sheath type, an eccentric sheath-core type, a parallel type, a multilayer type, and a sea-island type composite fiber. 複合繊維を構成するポリマー成分が、ポリオレフィン系、ポリエステル系及びポリアミド系から選ばれる少なくとも一つのポリマーである請求項６に記載の吸収性物品用液体非透過性シート。The liquid impermeable sheet for absorbent articles according to claim 6, wherein the polymer component constituting the composite fiber is at least one polymer selected from polyolefin-based, polyester-based and polyamide-based materials. メルトブロー不織布と積層用の繊維不織布の積層が、エンボスロールによる熱接着、超音波溶着、低融点ポリマー成分の融点以上で高融点ポリマー成分の融点未満の温度の熱風を利用した熱風循環接着、ホットメルトポリマーを使用したホットメルト接着から選ばれる少なくとも一つの接着による積層である請求項１に記載の吸収性物品用液体非透過性シート。Lamination of melt blown non-woven fabric and fiber non-woven fabric for laminating is hot bonding by embossing roll, ultrasonic welding, hot air circulation bonding using hot air with temperature higher than melting point of low melting polymer component and lower than melting point of high melting polymer component, hot melt The liquid-impermeable sheet for absorbent articles according to claim 1, wherein the liquid-impermeable sheet is for at least one adhesion selected from hot melt adhesion using a polymer. 請求項１〜１０のいずれか１項に記載の液体非透過性シートを一部に用いた吸収性物品。An absorbent article using a portion of the liquid impermeable sheet of any one of claims 1-10.
JP52345498A 1996-11-15 1997-11-12 Liquid impermeable sheet for absorbent articles Expired - Lifetime JP4442932B2 (en)

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