JP3821256B2 - Long fiber nonwoven fabric, method for producing the same, and absorbent article - Google Patents
Long fiber nonwoven fabric, method for producing the same, and absorbent article Download PDFInfo
- Publication number
- JP3821256B2 JP3821256B2 JP25061197A JP25061197A JP3821256B2 JP 3821256 B2 JP3821256 B2 JP 3821256B2 JP 25061197 A JP25061197 A JP 25061197A JP 25061197 A JP25061197 A JP 25061197A JP 3821256 B2 JP3821256 B2 JP 3821256B2
- Authority
- JP
- Japan
- Prior art keywords
- component
- fiber
- nonwoven fabric
- long
- inorganic powder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000000835 fiber Substances 0.000 title claims description 221
- 239000004745 nonwoven fabric Substances 0.000 title claims description 114
- 239000002250 absorbent Substances 0.000 title claims description 46
- 230000002745 absorbent Effects 0.000 title claims description 45
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 239000000843 powder Substances 0.000 claims description 61
- 238000000034 method Methods 0.000 claims description 52
- 238000002844 melting Methods 0.000 claims description 48
- 239000002131 composite material Substances 0.000 claims description 47
- 230000008018 melting Effects 0.000 claims description 47
- 229920001577 copolymer Polymers 0.000 claims description 45
- -1 acrylic ester Chemical class 0.000 claims description 43
- 229920006226 ethylene-acrylic acid Polymers 0.000 claims description 39
- 229920005989 resin Polymers 0.000 claims description 33
- 239000011347 resin Substances 0.000 claims description 33
- 229920005992 thermoplastic resin Polymers 0.000 claims description 23
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 20
- 239000002245 particle Substances 0.000 claims description 19
- 239000004743 Polypropylene Substances 0.000 claims description 15
- 229920001155 polypropylene Polymers 0.000 claims description 13
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 11
- 229920000139 polyethylene terephthalate Polymers 0.000 claims description 11
- 239000005020 polyethylene terephthalate Substances 0.000 claims description 11
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 10
- 238000002074 melt spinning Methods 0.000 claims description 10
- 239000004698 Polyethylene Substances 0.000 claims description 9
- 229920000573 polyethylene Polymers 0.000 claims description 9
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 7
- FPYJFEHAWHCUMM-UHFFFAOYSA-N maleic anhydride Chemical compound O=C1OC(=O)C=C1 FPYJFEHAWHCUMM-UHFFFAOYSA-N 0.000 claims description 7
- 239000004408 titanium dioxide Substances 0.000 claims description 7
- 229940037003 alum Drugs 0.000 claims description 6
- 239000000292 calcium oxide Substances 0.000 claims description 6
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 6
- 239000000395 magnesium oxide Substances 0.000 claims description 6
- 239000000377 silicon dioxide Substances 0.000 claims description 6
- 239000000454 talc Substances 0.000 claims description 6
- 229910052623 talc Inorganic materials 0.000 claims description 6
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 5
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims description 5
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 239000000306 component Substances 0.000 description 129
- 239000012792 core layer Substances 0.000 description 28
- 239000000463 material Substances 0.000 description 24
- 238000009987 spinning Methods 0.000 description 13
- 210000001124 body fluid Anatomy 0.000 description 12
- 239000010839 body fluid Substances 0.000 description 11
- JIGUQPWFLRLWPJ-UHFFFAOYSA-N Ethyl acrylate Chemical compound CCOC(=O)C=C JIGUQPWFLRLWPJ-UHFFFAOYSA-N 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 229920001903 high density polyethylene Polymers 0.000 description 6
- 239000004700 high-density polyethylene Substances 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- PNJWIWWMYCMZRO-UHFFFAOYSA-N pent‐4‐en‐2‐one Natural products CC(=O)CC=C PNJWIWWMYCMZRO-UHFFFAOYSA-N 0.000 description 6
- 238000010521 absorption reaction Methods 0.000 description 5
- 239000000853 adhesive Substances 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 238000001125 extrusion Methods 0.000 description 5
- 229920000092 linear low density polyethylene Polymers 0.000 description 5
- 239000004707 linear low-density polyethylene Substances 0.000 description 5
- 239000008280 blood Substances 0.000 description 4
- 210000004369 blood Anatomy 0.000 description 4
- 239000008358 core component Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000010410 layer Substances 0.000 description 4
- 229920001684 low density polyethylene Polymers 0.000 description 4
- 239000004702 low-density polyethylene Substances 0.000 description 4
- 239000000123 paper Substances 0.000 description 4
- 229920001897 terpolymer Polymers 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 210000002700 urine Anatomy 0.000 description 4
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 230000001070 adhesive effect Effects 0.000 description 3
- 238000005452 bending Methods 0.000 description 3
- 238000000113 differential scanning calorimetry Methods 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 230000004927 fusion Effects 0.000 description 3
- 230000001771 impaired effect Effects 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 229920000098 polyolefin Polymers 0.000 description 3
- 239000011342 resin composition Substances 0.000 description 3
- 230000001953 sensory effect Effects 0.000 description 3
- 239000004908 Emulsion polymer Substances 0.000 description 2
- 239000005977 Ethylene Substances 0.000 description 2
- 239000004831 Hot glue Substances 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 125000005396 acrylic acid ester group Chemical group 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000007334 copolymerization reaction Methods 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000004455 differential thermal analysis Methods 0.000 description 2
- 239000000839 emulsion Substances 0.000 description 2
- 125000000524 functional group Chemical group 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 238000012856 packing Methods 0.000 description 2
- 229920000728 polyester Polymers 0.000 description 2
- 229920001296 polysiloxane Polymers 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- 229920001169 thermoplastic Polymers 0.000 description 2
- 239000004416 thermosoftening plastic Substances 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- XGIAHMUOCFHQTI-UHFFFAOYSA-N Cl.Cl.Cl.Cl.CC Chemical compound Cl.Cl.Cl.Cl.CC XGIAHMUOCFHQTI-UHFFFAOYSA-N 0.000 description 1
- 206010021639 Incontinence Diseases 0.000 description 1
- 239000004594 Masterbatch (MB) Chemical class 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- 229920000297 Rayon Polymers 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- CQEYYJKEWSMYFG-UHFFFAOYSA-N butyl acrylate Chemical compound CCCCOC(=O)C=C CQEYYJKEWSMYFG-UHFFFAOYSA-N 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000002788 crimping Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- BXKDSDJJOVIHMX-UHFFFAOYSA-N edrophonium chloride Chemical compound [Cl-].CC[N+](C)(C)C1=CC=CC(O)=C1 BXKDSDJJOVIHMX-UHFFFAOYSA-N 0.000 description 1
- 238000004049 embossing Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229920001038 ethylene copolymer Polymers 0.000 description 1
- 238000009986 fabric formation Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 1
- 239000011976 maleic acid Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000012968 metallocene catalyst Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920005672 polyolefin resin Polymers 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000002964 rayon Substances 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 229920006302 stretch film Polymers 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 229920006027 ternary co-polymer Polymers 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Absorbent Articles And Supports Therefor (AREA)
- Artificial Filaments (AREA)
- Multicomponent Fibers (AREA)
- Nonwoven Fabrics (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、スパンボンド法により得られた長繊維不織布、その製造方法、及びそれを用いた吸収性物品に関するものである。特に本発明は、エチレン−アクリル酸エステル−無水マレイン酸共重合体を２０重量％以上含有し、かつ繊維表面の少なくとも一部を繊維の長さ方向に形成している第一成分と、第一成分よりも高融点の結晶性熱可塑性樹脂を第二成分としたスパンボンド法により得られた熱融着性複合長繊維不織布、その製造方法、及びそれを用いた吸収性物品に関するものである。
【０００２】
【従来の技術】
長繊維不織布の代表例であるスパンボンド不織布は、溶融紡糸口金から吐出した長繊維群をエアーサッカーなどに導入して牽引延伸し、開繊して捕集コンベア上に集積して繊維ウェブを得た後、長繊維相互間を適宜の手段で交絡あるいは熱融着させて製造されている。従って、連続繊維とも言える長繊維を構成繊維とするものであるため、短繊維を構成繊維とする短繊維不織布に比べて、引張強度等の機械的性質に優れている。また、溶融紡糸して得られた長繊維を、そのまま開繊及び集積して不織布が得られるため、短繊維を乾式法や湿式法で開繊及び集積して得られる不織布に比べて、合理的に生産しうるという利点があり、近年その生産量も大きく増加してきている。
【０００３】
また、熱融着性複合繊維としては、従来ポリプロピレンやポリエステルを高融点成分とし、高密度ポリエチレン、低密度のポリエチレン、直鎖状低密度ポリエチレンなどを低融点成分としたものが知られている。このような従来の熱融着性複合繊維は、通常ウェッブに形成された後、低融点成分の融点以上に加熱することによって各繊維間の接触部が軟化或いは溶融して接合し、例えば不織布を形成する。しかしながら、これら熱融着性複合繊維はその低融点成分の性質から、金属、紙、レーヨン、ガラスなど他の異質素材との接合性或いは接着性に乏しい。従って、上記のような不織布を他の異質素材と接合或いは接着させて使用したり、または他の素材と組み合わせて複合材料を形成する場合には、新たにバインダーを使用する必要があり、またバインダーを使用した場合であっても、その接着性は必ずしも良好なものではなかった。
【０００４】
また従来から医療衛生材料の紙おむつなどの使い捨ておむつや生理用ナプキン等の吸収性物品は、その態様によっても異なるが、尿や血液などの体液を吸収し漏れを防止するため、尿や血液などの体液を吸収し保持する吸収コア層と、吸収コア層を包むための液体透過性の吸収コア層のカバーと、その表面側（肌に接する側）に配置される液体透過性のトップシートと、吸収コア層の裏側面（トップシートが位置する側と反対側）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などから構成されており、更に、前記吸収コア層のカバーとトップシートとの間の位置または吸収コア層と吸収コア層のカバーとの間の位置に挿入されていて、クッション性を付与したり、体液を拡散したり、あるいは、吸収コア層に吸収された体液が肌側に逆戻りするのを防止するなどのいずれかの機能を付与するためのセカンドシートを有する構成のものも存在する。吸収コア層に吸収された体液が肌側に逆戻りするのを防止する機能は、例えばセカンドシートの繊維の充填密度を吸収コア層の繊維の充填密度よりも小さくして繊維充填密度の大きい方に毛細管現象などにより体液が吸収される原理などを応用したものであるが、特にこの方式に限定されるものではない。このほかにも更に種々の機能を付与するために更に他のシートが挿入され、より多層になっているものもある。
【０００５】
吸収コア層としては、例えばフラッフパルプなどのセルロース系繊維の集合体と高吸水性樹脂との組み合せが一般的であり、必要に応じ更に合成繊維が混合されたものなどを圧縮して固めたものが用いられている。前記吸収コア層を包むための液体透過性の吸収コア層のカバーとしては、通常ティツシュペーパーが用いられている。また、トップシートとしては、短繊維からなるスルーエアー不織布（不織布を構成する短繊維の繊維相互間の一部を熱風加熱により接着した不織布）や短繊維からなるエンボス不織布（熱エンボスロールと平滑表面を有するロール間を通過させて、不織布を構成する短繊維の繊維相互間の一部を接着した不織布）などが用いられており、また、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て、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いる。そして、これらの相互間は、必要な部分は適宜ホットメルト接着剤などで接着されている。
【０００６】
しかし、ホットメルト接着剤は、粘着性を有しており粘着剤で接着した場合の様に接着力は余り強くない、また、余り多量に用いると、これら各シートの目詰まりを生じさせ、通気性が損なわれたり、体液透過性が低下したりする問題がある。
【０００７】
【発明が解決しようとする課題】
スパンボンド長繊維不織布に関しては上記問題を解決するために、熱融着性複合長繊維不織布の熱融着成分として用いられる成分として、種々の官能基を有し、種々の素材に高い接着性を示す樹脂であるエチレン−アクリル酸エステル−無水マレイン酸共重合体を複合長繊維の一成分として使用する事を検討したが、このような樹脂は異質素材との接着性に優れるものの、非常に強い粘着性を有し摩擦係数が大きいという問題がある事がわかった。
【０００８】
このため、紡糸ノズル孔より吐出した糸条が金属製のエアーサッカーで牽引される際に繊維と金属との間或いは繊維相互間の摩擦によって繊度斑が生じたり、繊維が相互に融着して束になり開繊しにくいという問題があった。
【０００９】
また、エチレン−アクリル酸エステル−無水マレイン酸共重合体は、エチレン共重合体中に種々の官能基が導入されていることにより、低結晶性、低融点化または低軟化点化されている。この様に結晶性が低下している樹脂を用いた場合には、紡糸ノズル孔から溶融状態で吐出したその樹脂の糸条が結晶化し固化するまでの時間或いは距離（固化長）が著しく長くなっている。
【００１０】
従って、摩擦によって長繊維が束になり繊度斑や開繊不良を生じるだけでなく、長繊維相互間の距離は短くなることを引き金に、固化長が長くなった糸条が未だ溶融状態すなわち、低融点または低軟化点のエチレン−アクリル酸エステル−無水マレイン酸共重合体が溶融状態で接触するために、いわゆる糸切れが発生し操業性が悪いという問題も発生する。
【００１１】
特開平３−２８７８７５号には、エチレン−アクリル酸エステル−無水マレイン酸共重合体を低融点成分に用い、表面にシリコーン乳化重合体を実質的に表面付着し、繊維表面の摩擦係数を軽減させた熱融着性複合繊維が開示されている。従って、この技術を利用すれば、エチレン−アクリル酸エステル−無水マレイン酸共重合体を低融点成分に用いた繊維であっても、容易に均質性に優れた不織布が得られると考えられる。
【００１２】
しかしながら、この特開平３−２８７８７５号に記載の技術は、あくまでも短繊維を想定したものであり、この場合、シリコーン乳化重合体の様な仕上剤は、各種界面活性剤と混合して水系エマルジョンの形で繊維表面に付着するのが一般的である。長繊維不織布製造時に問題となるのは、金属製のエアーサッカーで牽引される際であるため、紡糸口金−エアサッカー間で付着する必要があるが、高速で走行する長繊維群への仕上剤の付着そのものが困難であること、エアーサッカーで付着液が飛散するなどの問題が生じる事、水系エマルジョンの表面張力によって繊維が集束し、またコロナ放電により同じ電荷を付与して帯電により開繊させる場合も帯電性が低下してしまうなどにより、実質的に開繊性が悪いと言う問題があり、直接長繊維不織布を製造するには不適当である。
【００１３】
すなわち、この特開平３−２８７８７５号公報に記載の技術を利用した場合であっても、開繊性が不充分で地合（不織布の均一性）が悪く、長繊維不織布の柔軟性や肌触り等の風合いもまだ十分なものではなく、またこの技術は、スパンボンド長繊維不織布製造に適合したものではなかった。
【００１４】
本発明は、上記の問題点を解決するためになされたものであり、高接着性、低温接着性、異種素材との接着性が良好で、得られる長繊維不織布の柔軟性や肌触り等の風合い、不織布の均一性に優れ、しかも紡糸性などの操業性も良好な複合繊維からなるスパンボンド法により得られた長繊維不織布を提供することを目的とするものである。
【００１５】
また、本発明は、従来の吸収性物品の前記問題点を解決し、吸収性物品の少なくとも一部に前記長繊維不織布を用いることにより、目詰まりなどが生じることもなく接着性を良好にし、使用中における吸収性物品を構成する層の剥離、崩れによって生じる問題などのない吸収性物品を提供することを目的とするものである。
【００１６】
本発明者らは、スパンボンド法による長繊維不織布について鋭意検討を重ねた結果、少なくとも低融点または低軟化点成分である第一成分へ無機物粉末を添加することにより、無機物粉末が繊維表面へ露出し、繊維表面へ微細な凹凸を付与でき、繊維相互間の接触面積が減少し紡糸中に繊維相互間が粘着することを防止できるので、糸切れなどを減少させ、操業性を良好にし、しかも無機物粉末の添加によってもエチレン−アクリル酸エステル−無水マレイン酸共重合体の結晶化温度の上昇はほとんど起こらず、結晶化度の増加も著しく小さく、従って、エチレン−アクリル酸エステル−無水マレイン酸共重合体の柔軟性や高接着性、低温接着性等の特徴を損なわず、柔軟性や肌触り等の風合いが良好かつ異種素材との接着性に優れる長繊維不織布が得られ、また、かかる長繊維不織布を、吸収性物品の少なくとも一部に用いることにより、目詰まりなどが生じることもなく接着性を良好にし、使用中における吸収性物品を構成する層の剥離または崩れによって生じる問題などのない吸収性物品が得られることを知り本発明を完成するに至った。
【００１７】
【課題を解決するための手段】
上記の課題を解決するため、本発明の長繊維不織布は、エチレン−アクリル酸エステル−無水マレイン酸共重合体を２０重量％以上含有し、かつ繊維表面の少なくとも一部を繊維の長さ方向に形成している第一成分と、第一成分よりも高融点の結晶性熱可塑性樹脂を第二成分とした熱融着性複合長繊維からなり、少なくとも第一成分に無機物粉末を含有し、前記無機物粉末の含有量が繊維中濃度にして５００〜５００００重量ｐｐｍ含有するスパンボンド法により得られた長繊維不織布である。
【００１８】
本発明の長繊維不織布に於ては、エチレン−アクリル酸エステル−無水マレイン酸共重合体の共重合組成が、無水マレイン酸分率が２〜５重量％、アクリル酸エステル分率が６〜３０重量％であることが好ましい。
【００１９】
また、本発明の長繊維不織布に於ては、エチレン−アクリル酸エステル−無水マレイン酸共重合体の融点が６０〜１１０℃であることが好ましい。
また、本発明の長繊維不織布に於ては、第一成分の樹脂成分がエチレン−アクリル酸エステル−無水マレイン酸共重合体とポリエチレンとの混合物であることが好ましい。
【００２０】
また、本発明の長繊維不織布に於ては、無機物粉末の粒子径が、平均粒子径で０．０４〜２μｍであることが好ましい。
また、本発明の長繊維不織布に於ては、無機物粉末が、二酸化チタン、シリカ、ミョウバン、炭酸カルシウム、酸化カルシウム、酸化マグネシウム、タルクから選ばれた少なくとも１種の無機物粉末であることが好ましい。
【００２１】
また、本発明の長繊維不織布に於ては、第二成分の結晶性熱可塑性樹脂がポリプロピレンであることが好ましい。
また、本発明の長繊維不織布に於ては、第二成分の結晶性熱可塑性樹脂がポリエチレンテレフタレートであることが好ましい。
【００２２】
また、本発明の吸収性物品は前記のいずれかに記載の長繊維不織布を、少なくとも一部に用いた吸収性物品である。
また、本発明の長繊維不織布の製造方法は、エチレン−アクリル酸エステル−無水マレイン酸共重合体を２０重量％以上含有した低融点樹脂成分と無機物粉末の混合物を第一成分として用い、第一成分よりも高融点の結晶性熱可塑性樹脂、又は無機物粉末が混合された第一成分よりも高融点の結晶性熱可塑性樹脂を第二成分として用いて、それぞれ個別の押出機に、第一成分が、繊維表面の少なくとも一部を繊維の長さ方向に形成し、無機物粉末の含有量が繊維中濃度にして５００〜５００００重量ｐｐｍ含有となるように投入し、複合繊維の第一成分と第二成分の容積割合が、第一成分：第二成分の比率で１０：９０〜９０：１０となるように、複合紡糸口金を用いて溶融紡糸し、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、開繊したのち、開繊された長繊維群は裏面に吸引装置を設けた無端ネット状コンベア上に、長繊維フリースとして捕集し、ポイントボンド法、熱風加熱法、高圧水流法、ニードルパンチ法、超音波加熱法から選ばれる不織布化を用いることを特徴とする。
【００２３】
【発明の実施の形態】
本発明の不織布は、エチレン−アクリル酸エステル−無水マレイン酸共重合体を２０重量％以上含有し、かつ繊維表面の少なくとも一部を繊維の長さ方向に形成している第一成分と、第一成分よりも高融点の結晶性熱可塑性樹脂を第二成分とした熱融着性複合長繊維からなり、少なくとも第一成分に無機物粉末を含有し、前記無機物粉末の含有量が繊維中濃度にして５００〜５００００重量ｐｐｍ含有してなるスパンボンド法により得られた長繊維不織布である。
【００２４】
前記エチレン−アクリル酸エステル−無水マレイン酸共重合体を２０重量％以上含有し、かつ繊維表面の少なくとも一部を繊維の長さ方向に形成している樹脂を第一成分とし、第一成分よりも高融点の結晶性熱可塑性樹脂を第二成分とした熱接着性複合繊維としては、第一成分が鞘成分、第二成分が芯成分となる鞘芯型の複合繊維、前記に於いて芯成分の断面における位置が偏心しているいわゆる鞘芯偏心型の複合繊維、第一成分と第二成分が貼り合わされているいわゆる並列型複合繊維（サイドバイサイド型複合繊維）が好適に用いられる。特に鞘芯偏心型複合繊維や並列型複合繊維を用いると捲縮繊維を容易に得ることが出来、嵩高で風合のよい長繊維不織布が得られる点では好ましい。並列型複合繊維の断面における第一成分と第二成分の割合（複合比）は１：１であってもよく、一方の成分が繊維断面において他方の成分より大きな断面積を占める形になっていてもよいことはもちろんである。
【００２５】
複合繊維の第一成分と第二成分の容積割合（繊維断面を採用した場合にはその断面の面積割合に該当する＝複合比）は、通常、第一成分：第二成分の比率で１０：９０〜９０：１０、好ましくは３０：７０〜７０：３０のものが用いられる。
【００２６】
本発明において第一成分に用いられる樹脂成分としては、エチレン−アクリル酸エステル−無水マレイン酸共重合体を２０重量％以上含有する樹脂が用いられる。
【００２７】
エチレン−アクリル酸エステル−無水マレイン酸共重合体としては、無水マレイン酸分率（すなわち無水マレイン酸成分の共重合割合）が約２〜５重量％、アクリル酸エステル分率（すなわちアクリル酸エステル成分の共重合割合）が約６〜３０重量％のエチレン−アクリル酸エステル−無水マレイン酸共重合体が好ましく用いられる。通常はエチレン−アクリル酸エステル−無水マレイン酸三元共重合体が用いられるが本発明の目的を疎外しないで若干の他の成分が共重合されていてもよい。無水マレイン酸分率が２〜５重量％、アクリル酸エステル分率が６〜３０重量％のエチレン−アクリル酸エステル−無水マレイン酸共重合体は、融点が低過ぎたり、また粘着性が大き過ぎることもなく、繊維表面を構成する材料としての必要な性質を満足しており、また、熱安定性も比較的よいので溶融紡糸においての熱分解、変質の問題も少なく好適であり、しかも他の異質素材との熱接着性が優れており好ましい。
【００２８】
本発明に於ては、エチレン−アクリル酸エステル−無水マレイン酸共重合体としては、融点が６０〜１１０℃のエチレン−アクリル酸エステル−無水マレイン酸共重合体が、紡糸性及び接着性が良好などの理由で好ましく用いられる。
【００２９】
本発明で用いる前記エチレン−アクリル酸エステル−無水マレイン酸共重合体を構成するアクリル酸エステル成分としては、特に制限するものではないが、工業的には一般にアクリル酸エチル、アクリル酸ブチルなどを用いた共重合体が広く用いられている事から、これらが入手も容易であり好ましく、また、アクリル酸エステル成分に由来する遊離アルコールのため、臭気や食品衛生上の観点で問題となる分野に於いては、臭気が強くなく、ポリオレフィン等衛生協議会の「ポリオレフィン等合成樹脂製食品包装等に関する自主規制基準」にも登録されているアクリル酸エチルが好ましく用いられる。
【００３０】
また、第一成分を構成する樹脂成分に於いては、エチレン−アクリル酸エステル−無水マレイン酸共重合体は、第一成分中の樹脂成分の合計重量に基づいて２０重量％以上含有していることが低温接着性や他の異質素材との接着性を良好に保つ上で必要であり、２０重量％未満では前記特性を十分発揮する事が出来ず好ましくない。エチレン−アクリル酸エステル−無水マレイン酸共重合体は、第一成分中の樹脂成分の合計重量に基づいて１００重量％の割合まで使用することも出来るが、必要に応じて、溶融紡糸が可能な範囲で比較的低融点または低軟化点の樹脂を混合して使用することができる。
【００３１】
第一成分においてエチレン−アクリル酸エステル−無水マレイン酸共重合体と混合して使用する比較的低融点または低軟化点の樹脂としては、例えば、ポリエチレン、ポリプロピレン、エチレン−プロピレン共重合体、エチレン−ブテン−プロピレン共重合体、低融点ポリエステル、低融点ポリアミドなどが例示される。これらの比較的低融点または低軟化点の樹脂のうちでは、相溶性と低融点温度を確保するうえからポリエチレンが好ましく、ポリエチレンは各種のものが使用できる。例えば高密度ポリエチレン、低密度ポリエチレン、直鎖状低密度ポリエチレンなどが好適に使用できる。また、ポリエチレンなどを併用することにより、溶融紡糸中における前述したエアーサッカーなどの金属との摩擦をより低減し、繊維間の接着をより好適に防止でき好ましい。
【００３２】
本発明において用いるエチレン−アクリル酸エステル−無水マレイン酸共重合体を２０重量％以上含有する第一成分の樹脂成分としては、第二成分の結晶性熱可塑性樹脂よりも低温で熱溶融または軟化して熱融着性を発揮し得るものであればよく、好ましくは、第二成分の結晶性熱可塑性樹脂が熱溶融または軟化する温度より５℃以上、より好ましくは３０℃以上低い温度で熱溶融または軟化し得るものが、得られた長繊維フリースを熱融着させる場合に第二成分への熱による物理的性質の低下などのダメージを与えず好ましい。
【００３３】
本発明で用いる第二成分の結晶性熱可塑性樹脂としては、前記第一成分のエチレン−アクリル酸エステル−無水マレイン酸共重合体を含有した樹脂成分の融点よりも、融点が高く、前記第一成分と共に複合紡糸ができる結晶性熱可塑性樹脂が用いられ、好ましくは、ポリプロピレンまたはポリエチレンテレフタレートが挙げられる。前記第二成分としてポリプロピレンを用いると、比較的柔軟な長繊維不織布が得られ好ましい。また、前記第二成分としてポリエチレンテレフタレートを用いた場合には、より強力が大きく、また、捲縮を発現させた時の弾力性（クッション性）のより優れた長繊維不織布を得ることができ好ましい。
【００３４】
用いる樹脂のＭＦＲ（メルトフローレート）は、特に限定するものではないが、第一成分、第二成分とも（但し、第二成分はオレフィン系樹脂を用いる場合）、一般的に１０〜１００ｇ／１０分のものが用いられる。また、第二成分の樹脂がオレフィン系重合体の場合は、チーグラー／ナッタ系触媒を用いて重合されたものや、いわゆるメタロセン系触媒を用いて重合されたもの等のいずれも使用できる。
【００３５】
本発明で用いる無機物粉末は、繊維表面に凹凸を付与せしめ、繊維同士の粘着を防止し得るものであればどの様なものを用いてもよい。
無機物粉末の粒子径は、平均粒子径で０．０４〜２μｍであることが好ましく、特に０．０４〜１μｍの範囲が好ましい。余り粒子径の小さいものを用いても、コストが高くなること、二次凝集を起こしやすく、フィルターや紡糸ノズルの目詰まりが生じたり、糸切れが発生して操業性が低下する原因になりやすいし、また、余りに粒子径が大き過ぎる場合には、無機物粉末の分散性が不良になったり、フィルターや紡糸ノズルの目詰まりが生じたり、糸切れが発生して操業性が低下する原因になりやすい傾向があるので、上記の範囲が特に好ましい。無機物粉末の粒子径は電子顕微鏡観察により測定し得る。例えば、複合長繊維中に含有されている無機物粉末の粒子径を測定する場合には、複合長繊維を真空下で加熱することにより、複合長繊維を構成している重合体と無機物粉末とを分離してから電子顕微鏡観察により測定することができる。その際に粒子が球形以外の形の場合には、粒子と同体積の球と仮定した場合の粒子径に換算する。
【００３６】
本発明で用いる無機物粉末の具体例としては、二酸化チタン、シリカ、ミョウバン、炭酸カルシウム、酸化カルシウム、酸化マグネシウム、タルクなど各種の安定な不活性な無機物粉末が挙げられる。これらの無機物粉末は、複合繊維表面へ微細な凹凸を付与する事ができ、その結果、紡糸中における繊維相互間の粘着を防止し、スパンボンド法により得られる複合長繊維不織布において、前述した様に繊度斑や開繊性が良好で、糸切れなどが改善され操業性がよく、しかも、これらの無機物粉末は造核作用が比較的小さい事で第一成分である低融点または高接着性のエチレン−アクリル酸エステル−無水マレイン酸共重合体を含有する樹脂成分の柔軟性や高接着性、低温接着性等の特徴を損なわず、柔軟性や肌触り等の風合いが良好でかつ他の異質部材との接着性に優れる長繊維不織布が得られるのである。特に、二酸化チタン、シリカ、ミョウバン、炭酸カルシウム、酸化カルシウム、酸化マグネシウム、タルクが造核作用などもより小さく好ましい。これらの無機物粉末は純粋なものを用いてもよいが、工業的にはコストが高くなるので、本発明の目的を損わない限り、不純物が含まれているものを使用することは何ら差し支えない。また、二酸化チタンにはルチル型二酸化チタンやアナターゼ型二酸化チタンがあり、いずれも使用できるが、耐候性及び耐熱性が良好な点においてルチル型二酸化チタンが好ましい。また、無機物粉末は、少なくとも第一成分に添加することが必要であり、第一成分と第二成分の両者に添加されていてもよい。
【００３７】
無機物粉末は、押出機に設けられているサイドフィーダーより導入して溶融押出しと共に混練添加してもよい。また、事前に例えば第一成分と混練したコンパウンドあるいはマスターバッチのような形態で用いて添加してもよい。この無機物粉末を混練する際は、通常、分散性をよくするために適宜の分散剤が用いられる。
【００３８】
無機物粉末の添加量は繊維中濃度にして５００〜５００００重量ｐｐｍ含有していることが必要である。無機物粉末の添加量がこれより少な過ぎると繊維表面の微細な凹凸付与による紡糸中に於ける繊維相互間の粘着防止効果が十分発揮されず、摩擦によって長繊維が束になり繊度斑や開繊不良を生じたり、糸切れが発生し操業性が低下してしまい、好ましくない。また、無機物粉末の添加量がこれより多過ぎるとフィルターや紡糸ノズルの目詰まりが生じたり、糸切れが発生して操業性が低下する原因になり好ましくない。尚、本発明の長繊維不織布を、特に生理用ナプキンに用いる場合には、無機物粉末の添加量は樹脂灰分の合計量で１２０００重量ｐｐｍ以下にすることが好ましい。
【００３９】
無機物粉末の添加量における繊維中濃度とは複合繊維の場合、繊維全体における濃度である。従って仮に第一成分のみに無機物粉末を添加した場合でも、その濃度は第一成分と第二成分とからなる複合繊維全体の平均的な濃度を示すことになる。
【００４０】
本発明において不織布を構成する複合長繊維の繊度は特に限定するものではなく、用いる素材樹脂の種類や用途に応じて適宜の繊度とすればよい。好ましくは１〜８ｄ／ｆ程度であり、例えば紙おむつ、生理用ナプキン、失禁パッド、手術用着衣、手術用掛布、ハップ材などで代表される衛生材料に用いる場合には１〜５ｄ／ｆが好ましい。
【００４１】
本発明の長繊維不織布の目付も特に限定はなく、用いる素材樹脂の種類や用途に応じて適宜の目付の不織布とすればよく、好ましくは１０〜５０ｇ／ｍ2 程度であり、特に衛生材料に用いる場合には１０〜３０ｇ／ｍ2 程度が好ましい。
【００４２】
以上説明した様な第一成分、第二成分の樹脂組成物を用い、溶融紡糸して口金から複合長繊維を得て、本発明にかかる長繊維不織布を得ることができるが、かかる長繊維不織布は、よく知られているスパンボンド法によって容易に製造することができる。
【００４３】
スパンボンド法は、すでによく知られているので詳細な説明は省略するが、例えば、エチレン−アクリル酸エステル−無水マレイン酸共重合体を２０重量％以上含有した低融点樹脂成分と無機物粉末の混合物を第一成分として用意し、第一成分よりも高融点の結晶性熱可塑性樹脂（必要に応じて無機物粉末が混合された結晶性熱可塑性樹脂を用いてもよい）を第二成分として用意する。これら樹脂組成物を、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。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無端ネット状コンベア上に、長繊維フリースとして捕集する。捕集した長繊維フリースは、無端コンベアに載せられたまま搬送され、加熱され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導入し、長繊維フリースを前記凹凸ロールの凸部に対応する区域において第一成分が溶融または軟化して長繊維相互間が熱融着された長繊維不織布を得る。長繊維不織布の目付は、例えば紡糸吐出速度（時間当たりの吐出量）や無端コンベアの移動速度などを調整することにより調整することができる。なお、長繊維フリースの不織布化（交絡あるいは熱融着）は、ポイントボンド法に限らず、その他、熱風加熱法、高圧水流法、ニードルパンチ法、超音波加熱法などで行われても良く、これら不織布化法の複数の組み合わせも採用し得る。
【００４４】
また、本発明の長繊維不織布はスパンボンド法によって製造されるので、引張強度等の機械的性質に優れている不織布が容易に得られ、また、溶融紡糸して得られた長繊維を、そのまま開繊及び集積して不織布が得られるため生産性が非常に優れ安価に製造でき好ましい。
【００４５】
かくして得られた、本発明の長繊維不織布は、高接着性、低温接着性、異種素材との接着性が良好で、得られる長繊維不織布の柔軟性や肌触り等の風合い、不織布の均一性に優れ、しかも紡糸性などの操業性も良好な複合繊維からなる長繊維不織布がえられるので、各種の用途に使用でき、特に他の素材と接合或いは接着させて使用したり、または他の素材と組み合わせて複合材料を形成する場合に容易に熱接着ができるので、かかる複合材料の製造に効果的に使用できる。
【００４６】
更に本発明の長繊維不織布は、生理用ナプキンや使い捨ておむつなどの吸水性物品の少なくとも一部に用いることもできる。
使い捨ておむつ、生理用ナプキン等の吸収性物品は、その態様によっても異なるが、前述した様に尿や血液などの体液を吸収し漏れを防止するため、尿や血液などの体液を吸収し保持する吸収コア層と、吸収コア層を包むための液体透過性の吸収コア層のカバーと、その表面側（肌に接する側）に配置される液体透過性のトップシートと、吸収コア層の裏側面（トップシートが位置する側と反対側）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などから構成されており、更に、前記吸収コア層のカバーとトップシートとの間の位置または吸収コア層と吸収コア層のカバーとの間の位置に挿入されていて、クッション性を付与したり、体液を拡散したり、あるいは、吸収コア層に吸収された体液が肌側に逆戻りするのを防止するなどのいずれかの機能を付与するためのセカンドシートを有する構成のものも存在する。このほかにも更に種々の機能を付与するために更に他のシートが挿入され、より多層になっているものもある。本発明の長繊維不織布は、他素材との接着性に優れるため、例えば吸収コア層のカバーやセカンドシート或いは吸収コア層中に用い、熱プレスや熱圧着させて、吸収性物品を薄型化したり、トップシートの浮きを防止し局部にトップシートがまとわりつかないようにでき好ましく使用される。前記の吸収コア層中に用いる場合には、例えば吸収コア層の中間に挿入して熱接着することにより、吸収コア層の吸収特性を余り阻害することなく、着用中の体重がかかった状態での身体の動きにより応力がかかって吸収コア層が崩れるのを防止する補強の作用を果たすことができる。尚、熱プレスや熱圧着は、使用部分にもよるが、通常多数の点接着ができる様な部分的な点接着が好ましく採用される。
【００４７】
【実施例】
以下、実施例、比較例を挙げて具体的に本発明を説明するが、本発明はこれらの実施例に挙げられたもののみに限定されるものではない。
【００４８】
実施例１〜８、比較例１〜４
表１に示したエチレン−アクリル酸エステル−無水マレイン酸三元共重合体またはこれと他の樹脂との混合物（表１中の第１成分（Ａ）の欄のエチレン−アクリル酸エステル−無水マレイン酸三元共重合体の使用割合（重量％）が１００％以外の場合は、前記三元共重合体の使用割合以外の残余が他の樹脂の使用割合になる。）と、表１に示した無機物粉末との混合物を第一成分として用意した。尚、無機物粉末の表１に示した添加率は、先に定義した繊維中濃度で示してある。従って第一成分中のみの無機物粉末の濃度は表に示した濃度よりも高くなる（第一成分中のみの無機物粉末の濃度は、繊維中濃度と複合比から容易に計算し得る。）。また、第二成分としては、同じく表１に示した性状の結晶性熱可塑性樹脂を用意した。尚、比較例４は第二成分のみの、すなわちポリプロピレンの単独繊維である。これら樹脂組成物を、それぞれ個別の６０ｍｍφ押出機に投入し、第一成分の押出温度は表１に記載の温度で、第二成分の押出温度は、ポリプロピレンの場合が２５０℃（比較例４の場合も２５０℃）で、第二成分がポリエチレンテレフタレートの場合には押出温度２８０℃で、それぞれ第一成分、第二成分の複合比に応じて両者のトータル量が２２００ｃｃ／分の割合となる様に押し出し（具体的には、第一成分（Ａ）、第二成分（Ｂ）の複合比Ａ／Ｂが５０／５０の場合には第一成分の押し出し割合は１１００ｃｃ／分の割合、第二成分の押し出し割合は１１００ｃｃ／分の割合となる）、それぞれ、表の複合様式の欄に記載した様な並列型、鞘芯型あるいは鞘芯偏心型の紡糸口金を用いて溶融紡糸した。紡糸口金は、孔径０．３５ｍｍの円形紡糸孔を口金の長手方向に５５０個×５列で持つものを使用した。この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、長繊維群を得た。続いて、エアーサッカーより排出された長繊維群を、コロナ放電装置にて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の間を通過させることで開繊した。開繊された長繊維群は裏面に吸引装置を設けた無端コンベア上に、長繊維フリースとして捕集した。このときの長繊維の繊度は２．２ｄ／ｆとなるように繊維の種類に応じてエアーサッカーの牽引延伸速度を適宜調整した。また、繊維中無機物の粉末の濃度は表記載の通りであった。捕集した長繊維フリースは、無端コンベアに載せられたまま搬送し、加熱され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導入した。導入された長繊維フリースは、凹凸ロールの凸部に対応する区域において第一成分が溶融または軟化して長繊維相互間が熱融着された長繊維不織布が得られた。この長繊維不織布の目付は３０ｇ／ｍ2 となるように繊維の種類に応じて無端コンベア移動速度を５０ｍ／ｍｉｎ．を基準にしてその前後で調整した。なお、凹凸ロールの周速度は無端コンベアの移動速度と同一にした。ロール間の線圧及びロール温度の設定は、長繊維不織布の剛軟度（ＪＩＳ Ｌ １０９６のＡ法の４５°カンチレバー法に準拠、但し試料の大きさは５ｃｍ×１５ｃｍとした。）の縦及び横方向の値の平均値が３５ｍｍ付近となるように適宜設定した。
【００４９】
なお、実施例における全ての不織布化（長繊維相互間の熱融着）は、風合などの官能試験時の条件合わせのためにポイントボンド法で行ったが、熱風加熱法、高圧水流法、ニードルパンチ法、超音波加熱法などで行われても良く、これら不織布化法複数の組み合わせであってもかまわない。
【００５０】
また、第二成分としてポリプロピレンを用いた場合にはＭＦＲ（メルトフローレート：ＪＩＳ Ｋ ７２１０ 表１の条件１４にて測定）が３５のものを使用した。また、第二成分としてポリエチレンテレフタレートを使用した場合は、そのＩＶ（極限粘度）値が０．６３、融点２５５℃のものを使用した。ＩＶ値の測定は、フェノールと四塩化エタンの等重量混合物を溶媒として、２０℃で測定した。また、第一成分に用いた各種ポリエチレンのＭＩ（メルトインデックス）はＪＩＳ Ｋ ７２１０ 表１の条件４にて測定したものである。
【００５１】
尚、表１に記載した無機物の平均粒子径は、シリカが０．０４μｍ、ＴｉＯ2 が０．２０μｍ、ミョウバンが０．９５μｍ、ＣａＣＯ3 が０．０８μｍ、ＣａＯが０．３５μｍ、ＭｇＯが０．１７μｍ、タルクが０．４０μｍのものを用いた。尚、ＴｉＯ2 としてはルチル型二酸化チタンを用いた。また表中、第二成分のＰＰはポリプロピレン、ＰＥＴはポリエチレンテレフタレートを意味する。また複合比の欄の容積比Ａ／Ｂは、Ａが第一成分、Ｂが第二成分の数値を示しており、複合繊維全体で１００としている。
【００５２】
以上の如く得られた長繊維不織布の評価結果を表２に示した。
尚、各評価項目の測定法や評価基準は次の通りである。
（他素材との接着強度＜剥離強さ＞）各実施例、比較例で得られた試料（長繊維不織布）と接着させる試料とをそれぞれ１０ｃｍ×５ｃｍの大きさに切断した。これら試料の四隅が揃うように重ね合わせ、その重ね合わせた試料の短辺方向、つまり幅方向に細長いヒートシールを施す。ヒートシールを施す位置は、重ね合わせた試料の短辺の一端より長手方向に１ｃｍ内側に入った部分から２ｃｍ内側迄の部分である。つまり試料の短辺の一端より短辺と平行に１ｃｍ幅のヒートシールのない余白部分を設け、その余白部分に隣接して短辺と平行に１ｃｍ幅のヒートシールを行った。ヒートシール条件は、温度１５０℃（上下とも）、３ｋｇ／ｃｍ2 ，５秒であり、ヒートシール装置として“ヒートシールテスター ＴＰ−７０１”（テスター産業株式会社製）を用いた。
【００５３】
上記操作によって得られた引張り試験用の試料を、ヒートシールを施さなかった側の他端の短辺側から開き、それぞれその端部を１０ｃｍ間隔に設定したテンシロン引張試験機（“ＲＤＭ−１００”株式会社オリエンテック製）のチャツク間に、捩れなどが生じないように固定した。剥離強さの測定は、引張り速度１００ｍｍ／分で測定し、剥離強さの計算方法はＪＩＳ Ｌ １０８６-1983 に準拠した。
【００５４】
（剛軟度）ＪＩＳ Ｌ １０９６のＡ法の４５°カンチレバー法に準拠し縦及び横方向について測定し、この平均値で表した。なお、試料の大きさは５ｃｍ×１５ｃｍとした。尚、剛軟度は、前述した様に、風合などの官能試験時の条件合わせのために長繊維相互間の熱融着をポイントボンド法でおこなって、一律３５ｍｍ付近となるように調整した。したがって表２には記載されていない。
【００５５】
（長繊維不織布の均一性指数）５×５ｃｍの試料を不織布の横方向に５点等間隔にて採取し、それぞれを１ｃｍ角に裁断し重量を測定した。これより、５点の試料それぞれについて（（最大値）−（最小値））×１００／（平均値）を算出し、これらの平均値を求めた。開繊斑や繊度斑の尺度として用いた。この値が小さいほど均一性が高く、８０以下で均一性がよいと考えて良い。
【００５６】
（風合い）モニター１０人が、長繊維不織布表面の手触りによる官能試験を行い、柔らかく、且つ、肌触りが良いと感じたら１点／１人で加点した。
（紡糸性）溶融紡糸を３時間行い、糸切れの発生回数を測定した。糸切れ回数が３回以下の時紡糸性は良好であると考えて良い。
【００５７】
（融点の測定法）
ＤＴＡ（示差熱分析）装置あるいはＤＳＣ（示差走査熱量測定）装置を用いて測定できるが、本発明ではＤＳＣ装置を用いた。そして本発明では下記の方法で測定したものを融点として定義した。
【００５８】
試料を約０．４ｍｇとり、０．０１ｍｇの位まで、重量を計る。試料容器は厚さが均一でかつ純度が９９．９〜９９．９９％のアルミニウム容器を使用する。試料を容器の中心部に薄く入れ、試料内に空気が入らないように一定加圧下で試料容器の底面に密着させる。雰囲気ガスは窒素ガスを使用し、酸素や水分を除去する。加熱速度は毎分１０℃とし、あらかじめ試料を一旦熱溶融させるなど試料に特定の処理を施さずに測定した。尚、融点の求め方は、ＪＩＳ Ｋ ７１２１-1987 に準拠した。
【００５９】
【表１】
【表２】
尚、表１、表２において使用した略号は次のものを示す。
表１中の略号
【００６２】
ＰＰ ：アイソタクチックポリプロピレン（ＭＦＲ ３５）
ＰＥＴ ：ポリエチレンテレフタレート（ＩＶ ０．６３、融点２５５℃）
ＨＤＰＥ ：高密度ポリエチレン（ＭＩ ２６）
ＬＬＤＰＥ：直鎖状低密度ポリエチレン（ＭＩ ３０）
ＬＤＰＥ ：低密度ポリエチレン（ＭＩ ３５）
表２中の略号
共重合体：エチレン−エチルアクリレート−無水マレイン酸三元共重合体（Ｅ−ＥＡ−ＭＡＨ）
ここでＥ：エチレン、ＥＡ：エチルアクリレート、ＭＡＨ：無水マレイン酸
ＥＨ１：ＥＡ分率 9.5重量％、ＭＡＨ分率 2.5 重量％、融点１０２℃
ＥＨ２：ＥＡ分率 21.9重量％、ＭＡＨ分率 3.0 重量％、融点８０℃
ＥＨ３：ＥＡ分率 22.9重量％、ＭＡＨ分率 3.4 重量％、融点７８℃
ＥＨ４：ＥＡ分率 29.4重量％、ＭＡＨ分率 2.6 重量％、融点６８℃
【００６３】
尚、比較例４は第一成分として高密度ポリエチレン（鞘成分）を単独で使用し、第二成分としてポリプロピレン（芯成分）を用いた鞘芯型複合長繊維からなる長繊維不織布を示している。
【００６４】
実施例１〜９で得られた本発明の長繊維不織布を、直鎖状低密度ポリエチレンの延伸フィルムからなるバックシート、ティッシュペーパーからなるカバーで包まれたフラッフパルプと高吸水性樹脂からなる吸収コア層、セカンドシート、鞘成分が高密度ポリエチレンで芯成分がポリプロピレンの鞘芯型複合繊維の短繊維からなるスルーエアー法で熱接着された不織布からなるトップシートがこの順で積層された使い捨ておむつのセカンドシートとして用いた。この場合、セカンドシートは、多数の点状の部分的熱圧着加工によりカバーシート及びティッシュペーパーからなるカバー（吸収コア層のカバー）と、熱接着されている。得られた使い捨ておむつを着用テストしたところ、トップシートの浮きもなく、局部にトップシートがまつわりつくことがなく、セカンドシートによる目詰まりの問題もなく、セカンドシートとカバーシート及び吸収コア層のカバーとの接着が良好な紙おむつが得られた。
【００６５】
【発明の効果】
本発明のスパンボンド法により得られた長繊維不織布は、エチレン−アクリル酸エステル−無水マレイン酸共重合体を２０重量％以上含有し、かつ繊維表面の少なくとも一部を繊維の長さ方向に形成している第一成分と、第一成分よりも高融点の結晶性熱可塑性樹脂を第二成分とした熱融着性複合長繊維からなり、少なくとも第一成分に無機物粉末を含有し、前記無機物粉末の含有量が繊維中濃度にして５００〜５００００重量ｐｐｍ含有しているので、高接着性、低温接着性にすぐれ、柔軟性や肌触り等の風合いが良好でかつ異種素材との接着性に優れる長繊維不織布を提供できる。しかも、長繊維不織布がスパンボンド法により得られた長繊維不織布である事により、引張強度等の機械的性質に優れている不織布が容易に得られ、また、溶融紡糸して得られた長繊維を、そのまま開繊及び集積して不織布が得られるため生産性が非常に優れ、比較的低コストで上記特性の優れた不織布が得られると共に、スパンボンド法により上述した作用効果が特に効果的に発揮され、スパンボンド法により得られた複合長繊維不織布の従来の欠点を効果的に改良することができ好ましい。
【００６６】
本発明の長繊維不織布に於て、エチレン−アクリル酸エステル−無水マレイン酸共重合体の共重合組成が、無水マレイン酸分率が２〜５重量％、アクリル酸エステル分率が６〜３０重量％である好ましい態様とすることにより、融点が低過ぎて溶融複合紡糸がしにくいという事もなく、また粘着性が大き過ぎることもなく、繊維表面を構成する材料としての必要な性質を満足しており、また、熱安定性も比較的よいので溶融紡糸においての熱分解、変質の問題も少なく、しかも他の異質素材との熱接着性が優れており、前記の効果をより好ましく発揮し得る長繊維不織布を提供でき好ましい。
【００６７】
また、本発明の長繊維不織布に於て、エチレン−アクリル酸エステル−無水マレイン酸共重合体の融点が６０〜１１０℃である好ましい態様とすることにより、紡糸性が良好で容易に長繊維不織布を得ることができ、また、得られた長繊維不織布の接着性も良好なので好ましい。
【００６８】
また、本発明の長繊維不織布に於て、第一成分の樹脂成分がエチレン−アクリル酸エステル−無水マレイン酸共重合体とポリエチレンとの混合物である好ましい態様とすることにより、ポリエチレンを併用することにより、溶融紡糸中における前述したエアーサッカーなどの金属との摩擦をより低減し、繊維間の接着をより好適に防止でき好ましい。
【００６９】
また、本発明の長繊維不織布に於て、無機物粉末の粒子径が、平均粒子径で０．０４〜２μｍである好ましい態様とすることにより、この範囲の平均粒子径の無機物粉末は、より小さい粒子径のものに比べてコストの上昇が少なく、無機物粉末の２次凝集を起こしたり、フィルターや紡糸ノズルの目詰まりが生じたり、糸切れが発生して操業性が低下することもなく、また、より粒子径が大きい無機物粉末を使用する場合に比べて、無機物粉末の分散性が不良になったり、フィルターや紡糸ノズルの目詰まりが生じたり、糸切れが発生して操業性が低下する恐れもなく、前記効果を十分に達成でき好ましい。
【００７０】
また、本発明の長繊維不織布に於て、無機物粉末が、二酸化チタン、シリカ、ミョウバン、炭酸カルシウム、酸化カルシウム、酸化マグネシウム、タルクから選ばれた少なくとも１種の無機物粉末である好ましい態様とすることにより、これらの無機物粉末は造核作用が比較的小さく、エチレン−アクリル酸エステル−無水マレイン酸共重合体を２０重量％以上含有する第一成分を構成する樹脂の結晶化温度の上昇はほとんど起こらず、結晶化度の増加も著しく小さく、従って、第一成分である低融点または低軟化点の前記樹脂の柔軟性や高接着性、低温接着性等の特徴をより損ないにくく、柔軟性や肌触り等の風合いが良好でかつ他の異質部材との接着性に優れる長繊維不織布が得られ好ましい。
【００７１】
また、本発明の長繊維不織布に於て、第二成分の結晶性熱可塑性樹脂がポリプロピレンである好ましい態様とする事により、比較的柔軟な長繊維不織布を得ることができ好ましい。
【００７２】
また、本発明の長繊維不織布に於て、第二成分の結晶性熱可塑性樹脂がポリエチレンテレフタレートである好ましい態様とする事により、より強力が大きく、また、捲縮を発現させた時の弾力性（クッション性）のより優れた長繊維不織布を得ることができ好ましい。
【００７４】
また、本発明の吸収性物品は、吸収性物品の少なくとも一部に前記長繊維不織布を用いることにより、目詰まりなどが生じることもなく接着性を良好にし、使用中における吸収性物品を構成する層の剥離または崩れによって生じる問題などのない吸収性物品を提供できる。[0001]
BACKGROUND OF THE INVENTION
The present inventionObtained by the spunbond methodLong fiber nonwoven fabric, Its manufacturing method,And an absorbent article using the same. In particular, the present invention includes a first component containing 20% by weight or more of an ethylene-acrylic acid ester-maleic anhydride copolymer and forming at least a part of the fiber surface in the fiber length direction, The second component is a crystalline thermoplastic resin having a melting point higher than that of the component.Obtained by the spunbond methodHeat-bondable composite long fiber nonwoven fabric, Its manufacturing method,And an absorbent article using the same.
[0002]
[Prior art]
Spunbond nonwoven fabric, which is a typical example of long fiber nonwoven fabric, introduces a long fiber group discharged from a melt spinneret into an air soccer, etc., draws and stretches it, opens it and collects it on a collection conveyor to obtain a fiber web. After that, the long fibers are manufactured by being entangled or heat-sealed by an appropriate means. Therefore, since the long fiber, which can be said to be a continuous fiber, is used as the constituent fiber, it is superior in mechanical properties such as tensile strength as compared with the short fiber nonwoven fabric using the short fiber as the constituent fiber. In addition, since the non-woven fabric can be obtained by opening and accumulating the long fibers obtained by melt spinning as compared with the non-woven fabric obtained by opening and accumulating the short fibers by a dry method or a wet method. In recent years, the production volume has increased greatly.
[0003]
Conventionally, heat-sealable composite fibers are known in which polypropylene or polyester is used as a high melting point component, and high density polyethylene, low density polyethylene, linear low density polyethylene, or the like is used as a low melting point component. Such a conventional heat-fusible conjugate fiber is usually formed on a web, and then heated to the melting point of the low melting point component or higher so that the contact portion between the fibers is softened or melted and joined. Form. However, these heat-fusible composite fibers are poor in bondability or adhesion to other heterogeneous materials such as metal, paper, rayon, and glass because of their low melting point components. Therefore, when a non-woven fabric such as that described above is used by bonding or adhering to another foreign material, or a composite material is formed by combining with another material, it is necessary to use a new binder. Even in the case of using, the adhesion was not always good.
[0004]
Conventionally, absorbent articles such as disposable diapers such as disposable diapers for medical hygiene materials and sanitary napkins differ depending on the mode, but in order to absorb bodily fluids such as urine and blood and prevent leakage, urine and blood etc. An absorbent core layer that absorbs and retains body fluids, a liquid-permeable absorbent core layer cover for wrapping the absorbent core layer, a liquid-permeable top sheet disposed on the surface side (side in contact with the skin), and absorption It is arranged on the back side of the core layer (the side opposite to the side on which the top sheet is located), and is composed of a liquid non-permeable back sheet for preventing the absorbed body fluid from leaking to the outside. It is inserted at a position between the core layer cover and the top sheet or between the absorbent core layer and the absorbent core layer cover to provide cushioning properties, diffuse body fluids, It would also be present in the configuration having a second sheet for body fluids absorbed into the layer to impart any of the functions, such as to prevent the back the skin side. The function of preventing the body fluid absorbed in the absorbent core layer from returning to the skin side is, for example, that the fiber packing density of the second sheet is made smaller than the fiber packing density of the absorbent core layer and the fiber filling density is larger. Although this applies the principle of body fluid absorption by capillarity or the like, it is not particularly limited to this method. In addition to this, there are also sheets in which other sheets are further inserted to give various functions to form a multilayer.
[0005]
As the absorbent core layer, for example, a combination of an aggregate of cellulosic fibers such as fluff pulp and a highly water-absorbent resin is generally used. Is used. As the cover of the liquid-permeable absorbent core layer for wrapping the absorbent core layer, tissue paper is usually used. Moreover, as a top sheet, a through-air nonwoven fabric composed of short fibers (nonwoven fabric in which a part of short fibers constituting the nonwoven fabric is bonded by hot air heating) or an embossed nonwoven fabric composed of short fibers (a hot embossing roll and a smooth surface) A non-woven fabric in which a part of short fibers constituting the non-woven fabric is bonded to each other, and a thermoplastic film is used as the back sheet. The thermoplastic film generally has innumerable fine holes in order to prevent internal stuffiness during wearing, and is generally breathable. Also, a composite with a non-woven fabric is used from the viewpoint of improving the plastic feel and appearance peculiar to the film and improving the strength. In addition, necessary portions of these members are appropriately bonded with a hot melt adhesive or the like.
[0006]
However, hot melt adhesives are sticky and do not have a strong adhesive strength as if they were adhered with an adhesive, and if they are used in excessive amounts, they will cause clogging of these sheets and aeration. There is a problem that the performance is impaired or the fluid permeability is lowered.
[0007]
[Problems to be solved by the invention]
SpunbondIn order to solve the above-mentioned problems concerning the long-fiber nonwoven fabric, as a component used as a heat-fusion component of the heat-fusible composite long-fiber nonwoven fabric, a resin having various functional groups and showing high adhesion to various materials Although the use of ethylene-acrylic acid ester-maleic anhydride copolymer as a component of composite long fiber was examined, such a resin has excellent adhesion to foreign materials, but very strong tackiness It has been found that there is a problem that the friction coefficient is large.
[0008]
For this reason, when the yarn discharged from the spinning nozzle hole is pulled by a metal air soccer ball, fineness spots are generated due to friction between the fiber and the metal or between the fibers, or the fibers are fused to each other. There was a problem that bundles were difficult to open.
[0009]
In addition, the ethylene-acrylic acid ester-maleic anhydride copolymer has a low crystallinity, a low melting point, or a low softening point due to the introduction of various functional groups in the ethylene copolymer. In the case of using a resin having reduced crystallinity in this way, the time or distance (solidification length) until the resin yarn discharged in a molten state from the spinning nozzle hole crystallizes and solidifies becomes remarkably long. ing.
[0010]
Therefore, not only the long fibers are bundled due to friction, causing fineness unevenness and poor opening, but also the distance between the long fibers is shortened, the yarn with increased solidification length is still in a molten state, that is, Since the ethylene-acrylic acid ester-maleic anhydride copolymer having a low melting point or a low softening point comes into contact in a molten state, so-called yarn breakage occurs, resulting in poor operability.
[0011]
In JP-A-3-287875, an ethylene-acrylic acid ester-maleic anhydride copolymer is used as a low melting point component, and a silicone emulsion polymer is substantially adhered to the surface to reduce the friction coefficient of the fiber surface. Further disclosed is a heat-fusible conjugate fiber. Therefore, if this technique is used, it is considered that a nonwoven fabric excellent in homogeneity can be easily obtained even with a fiber using an ethylene-acrylic acid ester-maleic anhydride copolymer as a low melting point component.
[0012]
However, the technique described in JP-A-3-287875 is intended only for short fibers. In this case, a finishing agent such as a silicone emulsion polymer is mixed with various surfactants to form an aqueous emulsion. It is common to adhere to the fiber surface in the form. The problem in producing long-fiber nonwoven fabric is when it is pulled by metal air soccer, so it is necessary to adhere between the spinneret and air soccer, but it is a finishing agent for long fiber groups that run at high speed. The adhesion itself is difficult, the problem is that the adhering liquid is scattered by air soccer, the fibers are focused by the surface tension of the water-based emulsion, and the same charge is given by corona discharge to open the fiber by charging. Even in this case, there is a problem that the spreadability is substantially poor due to a decrease in chargeability, and it is not suitable for directly producing a long fiber nonwoven fabric.
[0013]
That is, even when the technique described in Japanese Patent Laid-Open No. 3-287875 is used, the fiber-opening property is insufficient and the formation (non-uniformity of the nonwoven fabric) is poor, and the flexibility and the feel of the long-fiber nonwoven fabric are good. Is still not enough, and this technologySpunbondIt was not suitable for production of long fiber nonwoven fabric.
[0014]
The present invention has been made to solve the above problems, and has high adhesion, low-temperature adhesion, good adhesion to different materials, and the texture of the obtained long fiber nonwoven fabric such as flexibility and touch. It is made of a composite fiber with excellent uniformity of nonwoven fabric and excellent operability such as spinnability.Obtained by the spunbond methodThe object is to provide a long-fiber nonwoven fabric.
[0015]
In addition, the present invention solves the above-mentioned problems of conventional absorbent articles, and by using the long-fiber nonwoven fabric for at least a part of the absorbent article, the adhesiveness is improved without causing clogging, An object of the present invention is to provide an absorbent article free from problems caused by peeling or collapse of layers constituting the absorbent article during use.
[0016]
The inventors haveLong-fiber nonwoven fabric by spunbond methodAs a result of intensive studies, by adding inorganic powder to the first component that is at least a low melting point or low softening point component, the inorganic powder is exposed to the fiber surface, and fine irregularities can be imparted to the fiber surface, so Since the contact area between the fibers is reduced and the fibers are prevented from sticking to each other during spinning, the yarn breakage and the like are reduced, the operability is improved, and the addition of inorganic powder also makes ethylene-acrylate-anhydrous maleic acid. The crystallization temperature of the acid copolymer hardly increases, and the increase in crystallinity is extremely small. Therefore, the flexibility, high adhesion, low temperature adhesion, etc. of the ethylene-acrylic acid ester-maleic anhydride copolymer The long fiber nonwoven fabric having a good texture such as flexibility and touch and excellent adhesion to dissimilar materials can be obtained, and the long fiber nonwoven fabric can be used as an absorbent article. By using it at least in part, it is possible to obtain an absorbent article that has good adhesion without clogging and the like, and is free from problems caused by peeling or collapse of the layers constituting the absorbent article during use. Knowing that, the present invention has been completed.
[0017]
[Means for Solving the Problems]
In order to solve the above problems, the long-fiber nonwoven fabric of the present invention contains 20% by weight or more of an ethylene-acrylic acid ester-maleic anhydride copolymer, and at least a part of the fiber surface is in the fiber length direction. The first component is formed, and consists of a heat-fusible composite long fiber having a crystalline thermoplastic resin having a melting point higher than that of the first component as a second component, containing at least the first component as an inorganic powder, The inorganic powder content is 500 to 50000 ppm by weight in the fiber concentration.It is a long-fiber nonwoven fabric obtained by the spunbond method..
[0018]
In the long fiber nonwoven fabric of the present invention, the copolymer composition of ethylene-acrylic acid ester-maleic anhydride copolymer has a maleic anhydride fraction of 2 to 5% by weight and an acrylic ester fraction of 6 to 30. It is preferable that it is weight%.
[0019]
Moreover, in the long fiber nonwoven fabric of this invention, it is preferable that melting | fusing point of an ethylene-acrylic acid ester-maleic anhydride copolymer is 60-110 degreeC.
Moreover, in the long fiber nonwoven fabric of this invention, it is preferable that the resin component of a 1st component is a mixture of ethylene-acrylic acid ester-maleic anhydride copolymer and polyethylene.
[0020]
Moreover, in the long fiber nonwoven fabric of this invention, it is preferable that the particle diameter of inorganic powder is 0.04-2 micrometers in average particle diameter.
In the long fiber nonwoven fabric of the present invention, the inorganic powder is preferably at least one inorganic powder selected from titanium dioxide, silica, alum, calcium carbonate, calcium oxide, magnesium oxide, and talc.
[0021]
In the long-fiber nonwoven fabric of the present invention, the second component crystalline thermoplastic resin is preferably polypropylene.
In the long-fiber nonwoven fabric of the present invention, the second component crystalline thermoplastic resin is preferably polyethylene terephthalate.
[0022]
Moreover, the absorbent article of this invention is an absorbent article which used the long fiber nonwoven fabric in any one of the above for at least one part.
Moreover, the manufacturing method of the long-fiber nonwoven fabric of the present invention uses a mixture of a low melting point resin component containing 20 wt% or more of an ethylene-acrylic acid ester-maleic anhydride copolymer and an inorganic powder as the first component, A crystalline thermoplastic resin having a melting point higher than that of the component, or a crystalline thermoplastic resin having a melting point higher than that of the first component mixed with inorganic powder is used as the second component, and the first component However, at least part of the fiber surface is formed in the length direction of the fiber, and the inorganic powder is added so that the concentration in the fiber is 500 to 50,000 ppm by weight. The fiber group discharged from the spinneret into an air soccer ball is melt-spun using a composite spinneret so that the volume ratio of the two components is 10:90 to 90:10 in the ratio of the first component to the second component. Introduce After drawing and opening, the group of long fibers that have been opened is collected as a long fiber fleece on an endless net-like conveyor with a suction device on the back, and the point bond method, hot air heating method, high-pressure water flow method , Using a nonwoven fabric selected from a needle punch method and an ultrasonic heating method.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
The nonwoven fabric of the present invention contains an ethylene-acrylic acid ester-maleic anhydride copolymer of 20% by weight or more, and at least a part of the fiber surface is formed in the fiber length direction; It consists of a heat-fusible composite continuous fiber with a crystalline thermoplastic resin having a melting point higher than that of one component as the second component, and at least the first component contains an inorganic powder, and the content of the inorganic powder is adjusted to a concentration in the fiber. Containing 500 to 50000 ppm by weightObtained by the spunbond methodIt is a long fiber nonwoven fabric.
[0024]
A resin containing at least 20% by weight of the ethylene-acrylic acid ester-maleic anhydride copolymer and forming at least a part of the fiber surface in the length direction of the fiber is a first component. As the heat-adhesive conjugate fiber comprising a high-melting crystalline thermoplastic resin as the second component, a sheath-core type conjugate fiber in which the first component is a sheath component and the second component is a core component, So-called sheath-core eccentric composite fibers in which the positions of the components in the cross-section are eccentric, and so-called parallel composite fibers (side-by-side composite fibers) in which the first component and the second component are bonded together are preferably used. In particular, the use of a sheath-core eccentric composite fiber or a side-by-side composite fiber is preferable in that a crimped fiber can be easily obtained and a bulky nonwoven fabric having a good texture can be obtained. The ratio (composite ratio) of the first component and the second component in the cross section of the parallel type composite fiber may be 1: 1, and one component occupies a larger cross-sectional area than the other component in the fiber cross section. Of course, you may.
[0025]
The volume ratio of the first component and the second component of the composite fiber (corresponding to the area ratio of the cross section when the fiber cross section is adopted = composite ratio) is usually 10: 90-90: 10, preferably 30: 70-70: 30 are used.
[0026]
As the resin component used as the first component in the present invention, a resin containing 20% by weight or more of an ethylene-acrylic acid ester-maleic anhydride copolymer is used.
[0027]
The ethylene-acrylic acid ester-maleic anhydride copolymer has a maleic anhydride fraction (that is, a copolymerization ratio of the maleic anhydride component) of about 2 to 5% by weight, and an acrylic ester fraction (that is, an acrylic ester component). An ethylene-acrylic acid ester-maleic anhydride copolymer having a copolymerization ratio of about 6 to 30% by weight is preferably used. Usually, an ethylene-acrylic acid ester-maleic anhydride terpolymer is used, but some other components may be copolymerized without excluding the object of the present invention. An ethylene-acrylic acid ester-maleic anhydride copolymer having a maleic anhydride fraction of 2 to 5% by weight and an acrylic ester fraction of 6 to 30% by weight has a melting point that is too low and is too sticky. In addition, it satisfies the necessary properties as a material constituting the fiber surface, and also has a relatively good thermal stability, which is suitable for few problems of thermal decomposition and alteration in melt spinning. The thermal adhesiveness with a foreign material is excellent and preferable.
[0028]
In the present invention, as the ethylene-acrylic acid ester-maleic anhydride copolymer, an ethylene-acrylic acid ester-maleic anhydride copolymer having a melting point of 60 to 110 ° C. has good spinnability and adhesiveness. It is preferably used for such reasons.
[0029]
The acrylic acid ester component constituting the ethylene-acrylic acid ester-maleic anhydride copolymer used in the present invention is not particularly limited, but in general, ethyl acrylate, butyl acrylate, etc. are used industrially. These copolymers are easily available and preferred, and are free alcohols derived from acrylic acid ester components, so they are used in fields that are problematic in terms of odor and food hygiene. For example, ethyl acrylate which is not strong in odor and is registered in “Self-regulatory standards for food packaging made of synthetic resin such as polyolefin” of the Sanitation Council for Polyolefins is preferably used.
[0030]
Further, in the resin component constituting the first component, the ethylene-acrylic acid ester-maleic anhydride copolymer is contained in an amount of 20% by weight or more based on the total weight of the resin component in the first component. This is necessary for maintaining good low-temperature adhesiveness and adhesion to other foreign materials, and if it is less than 20% by weight, the above-mentioned characteristics cannot be exhibited sufficiently, which is not preferable. The ethylene-acrylic acid ester-maleic anhydride copolymer can be used up to a ratio of 100% by weight based on the total weight of the resin components in the first component, but can be melt-spun if necessary. A resin having a relatively low melting point or a low softening point can be mixed and used.
[0031]
Examples of the resin having a relatively low melting point or low softening point used by mixing with the ethylene-acrylic acid ester-maleic anhydride copolymer in the first component include, for example, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene- Examples include butene-propylene copolymers, low melting point polyesters, and low melting point polyamides. Among these resins having a relatively low melting point or low softening point, polyethylene is preferable from the viewpoint of ensuring compatibility and a low melting point temperature, and various types of polyethylene can be used. For example, high density polyethylene, low density polyethylene, linear low density polyethylene, and the like can be suitably used. Further, it is preferable to use polyethylene or the like in combination so that friction with a metal such as the above-described air soccer during melt spinning can be further reduced and adhesion between fibers can be more suitably prevented.
[0032]
As the first component resin component containing 20% by weight or more of the ethylene-acrylic acid ester-maleic anhydride copolymer used in the present invention, it is thermally melted or softened at a lower temperature than the crystalline thermoplastic resin of the second component. It is sufficient that it can exhibit heat-fusibility, and it is preferable that the second component crystalline thermoplastic resin is heat-melted at a temperature 5 ° C. or more, more preferably 30 ° C. or more lower than the temperature at which it melts or softens. Alternatively, those that can be softened are preferable since they do not cause damage such as a decrease in physical properties due to heat to the second component when the obtained long fiber fleece is heat-sealed.
[0033]
As the second component crystalline thermoplastic resin used in the present invention, the melting point is higher than the melting point of the resin component containing the first component ethylene-acrylic ester-maleic anhydride copolymer, A crystalline thermoplastic resin capable of complex spinning with the components is used, and preferably polypropylene or polyethylene terephthalate is used. When polypropylene is used as the second component, it is preferable because a relatively flexible long fiber nonwoven fabric is obtained. In addition, when polyethylene terephthalate is used as the second component, it is preferable because a long fiber nonwoven fabric having higher strength and superior elasticity (cushioning property) when crimped is obtained can be obtained. .
[0034]
The MFR (melt flow rate) of the resin to be used is not particularly limited, but both the first component and the second component (provided that the second component uses an olefin resin) are generally 10 to 100 g / 10. Minutes are used. When the second component resin is an olefin polymer, any of those polymerized using a Ziegler / Natta catalyst or polymerized using a so-called metallocene catalyst can be used.
[0035]
As the inorganic powder used in the present invention, any powder may be used as long as it can impart unevenness to the fiber surface and prevent adhesion between the fibers.
The particle diameter of the inorganic powder is preferably 0.04 to 2 μm in terms of average particle diameter, and particularly preferably in the range of 0.04 to 1 μm. Even if a product with a too small particle size is used, the cost is high, secondary aggregation is likely to occur, the filter and spinning nozzle are clogged, and thread breakage is likely to cause operability. However, if the particle size is too large, the dispersibility of the inorganic powder may be poor, the filter or spinning nozzle may be clogged, thread breakage may occur, and operability may be reduced. The above range is particularly preferred because it tends to be easy. The particle size of the inorganic powder can be measured by observation with an electron microscope. For example, when measuring the particle size of the inorganic powder contained in the composite long fiber, the polymer constituting the composite long fiber and the inorganic powder are heated by heating the composite long fiber under vacuum. It can measure by electron microscope observation after isolate | separating. In this case, if the particle has a shape other than a sphere, it is converted to a particle diameter assuming a sphere having the same volume as the particle.
[0036]
Specific examples of the inorganic powder used in the present invention include various stable and inert inorganic powders such as titanium dioxide, silica, alum, calcium carbonate, calcium oxide, magnesium oxide, and talc. These inorganic powders can give fine irregularities to the surface of the composite fiber, and as a result, prevent sticking between fibers during spinning,Obtained by lawIn composite long-fiber nonwoven fabric, fineness unevenness and spreadability are good as described above, thread breakage is improved and operability is good, and these inorganic powders have a relatively small nucleating action, which is the first component. The resin component containing the low-melting-point or high-adhesive ethylene-acrylic acid ester-maleic anhydride copolymer does not impair the characteristics such as flexibility, high adhesion, low-temperature adhesion, etc. A long fiber nonwoven fabric having a good texture and excellent adhesion to other foreign members can be obtained. In particular, titanium dioxide, silica, alum, calcium carbonate, calcium oxide, magnesium oxide, and talc are preferable because of their smaller nucleating action. Although these inorganic powders may be used purely, they are industrially expensive, so it is acceptable to use those containing impurities as long as the object of the present invention is not impaired. . Titanium dioxide includes rutile titanium dioxide and anatase titanium dioxide, both of which can be used, but rutile titanium dioxide is preferable in terms of good weather resistance and heat resistance. Further, the inorganic powder needs to be added to at least the first component, and may be added to both the first component and the second component.
[0037]
The inorganic powder may be introduced from a side feeder provided in the extruder and kneaded and added together with melt extrusion. Further, it may be added in the form of a compound or a masterbatch kneaded with the first component in advance. When kneading the inorganic powder, an appropriate dispersant is usually used to improve dispersibility.
[0038]
The added amount of the inorganic powder must be 500 to 50000 ppm by weight in the fiber. If the amount of inorganic powder added is too small, the effect of preventing adhesion between fibers during spinning due to the provision of fine irregularities on the fiber surface will not be sufficiently exerted, and long fibers will be bundled by friction, resulting in fineness spots and fiber opening. It is not preferable because defects occur or thread breakage occurs and operability decreases. On the other hand, if the amount of the inorganic powder added is too large, the filter or spinning nozzle may become clogged, or thread breakage may occur, leading to a decrease in operability. In addition, when using the long-fiber nonwoven fabric of this invention especially for a sanitary napkin, it is preferable that the addition amount of an inorganic powder shall be 12000 weight ppm or less with the total amount of resin ash.
[0039]
In the case of a composite fiber, the concentration in the fiber in the added amount of the inorganic powder is the concentration in the whole fiber. Therefore, even if the inorganic powder is added only to the first component, the concentration indicates the average concentration of the entire composite fiber composed of the first component and the second component.
[0040]
In the present invention, the fineness of the composite long fiber constituting the nonwoven fabric is not particularly limited, and may be an appropriate fineness depending on the type and use of the material resin used. Preferably, it is about 1 to 8 d / f. For example, when used for sanitary materials typified by disposable diapers, sanitary napkins, incontinence pads, surgical clothes, surgical cloths, and wrapping materials, 1 to 5 d / f is preferable. preferable.
[0041]
The basis weight of the long-fiber nonwoven fabric of the present invention is not particularly limited, and may be a nonwoven fabric with an appropriate basis weight depending on the type and application of the material resin used, preferably 10 to 50 g / m.210-30 g / m, especially when used for sanitary materials2The degree is preferred.
[0042]
The long fiber nonwoven fabric according to the present invention can be obtained by using the resin composition of the first component and the second component as described above, and melt spinning to obtain a composite continuous fiber from the die. Can be easily produced by the well-known spunbond method.
[0043]
The spunbond method is already well known and will not be described in detail. For example, a mixture of a low melting point resin component containing 20% by weight or more of an ethylene-acrylic ester-maleic anhydride copolymer and an inorganic powder Is prepared as a first component, and a crystalline thermoplastic resin having a melting point higher than that of the first component (a crystalline thermoplastic resin mixed with inorganic powder may be used if necessary) is prepared as a second component. . These resin compositions are respectively put into individual extruders and melt-spun using a composite 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 collected as long fiber fleece on an endless net-like conveyor provided with a suction device on the back side. The collected long fiber fleece is transported while being placed on an endless conveyor, and is introduced between the pressurized rolls of a point bond processing machine composed of a heated uneven roll and a smooth roll, and the long fiber fleece is introduced. In the area corresponding to the convex part of the concave-convex roll, the first component is melted or softened to obtain a long-fiber nonwoven fabric in which the long fibers are heat-sealed. The basis weight of the long fiber nonwoven fabric can be adjusted, for example, by adjusting the spinning discharge speed (discharge amount per hour), the moving speed of the endless conveyor, and the like. In addition, the non-woven fabric (entanglement or thermal fusion) of the long fiber fleece is not limited to the point bond method, and may be performed by a hot air heating method, a high-pressure water flow method, a needle punch method, an ultrasonic heating method, etc. A plurality of combinations of these nonwoven fabric forming methods can also be employed.
[0044]
The long fiber nonwoven fabric of the present inventionHaPan bond methodBecause it is manufactured byNonwoven fabrics with excellent mechanical properties such as tensile strength can be easily obtained, and long fibers obtained by melt spinning can be opened and accumulated as they are to obtain nonwoven fabrics. Can be produced.
[0045]
The long-fiber nonwoven fabric of the present invention thus obtained has high adhesion, low-temperature adhesion, good adhesion to dissimilar materials, softness of the obtained long-fiber nonwoven fabric, texture such as touch, and uniformity of the nonwoven fabric. A long-fiber non-woven fabric made of composite fibers that is excellent and also has good operability such as spinnability can be obtained, so it can be used for various purposes, especially by joining or bonding to other materials, or with other materials Since heat bonding can be easily performed when a composite material is formed by combination, it can be effectively used for manufacturing such a composite material.
[0046]
Furthermore, the long-fiber nonwoven fabric of the present invention can also be used for at least a part of water-absorbing articles such as sanitary napkins and disposable diapers.
Absorbent articles such as disposable diapers and sanitary napkins vary depending on the mode, but absorb and hold body fluids such as urine and blood in order to absorb body fluids such as urine and blood and prevent leakage as described above. An absorbent core layer, a liquid-permeable absorbent core layer cover for wrapping the absorbent core layer, a liquid-permeable top sheet disposed on the surface side (side contacting the skin), and the back side surface of the absorbent core layer ( It is arranged on the side opposite to the side on which the top sheet is located, and is composed of a liquid non-permeable back sheet for preventing the absorbed body fluid from leaking to the outside, and further the cover and top of the absorbent core layer Body fluid inserted in a position between the seats or a position between the absorbent core layer and the cover of the absorbent core layer to impart cushioning properties, diffuse body fluid, or be absorbed by the absorbent core layer On the skin side It would also be present in the configuration having a second sheet for providing any of the functions, such as to prevent the return. In addition to this, there are also sheets in which other sheets are further inserted to give various functions to form a multilayer. The long fiber nonwoven fabric of the present invention is excellent in adhesiveness to other materials. For example, it is used in a cover of an absorbent core layer, a second sheet or an absorbent core layer, and heat absorbent or thermocompressed to make the absorbent article thin. The top sheet is preferably used because it prevents the top sheet from floating and prevents the top sheet from clinging to the local area. When used in the absorbent core layer, for example, by inserting it in the middle of the absorbent core layer and thermally bonding it, without excessively inhibiting the absorption characteristics of the absorbent core layer, with the weight applied while wearing It is possible to perform a reinforcing action to prevent the absorption core layer from collapsing due to stress applied by the movement of the body. In addition, although a hot press and thermocompression bonding are based on a use part, the partial point adhesion | attachment in which many point adhesions are normally employable is employ | adopted preferably.
[0047]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited only to what was mentioned to these Examples.
[0048]
Examples 1-8, Comparative Examples 1-4
Ethylene-acrylic acid ester-maleic anhydride terpolymer shown in Table 1 or a mixture thereof with another resin (ethylene-acrylic acid ester-maleic anhydride in the column of the first component (A) in Table 1) When the usage ratio (% by weight) of the acid terpolymer is other than 100%, the remainder other than the usage ratio of the ternary copolymer becomes the usage ratio of other resins. A mixture with the inorganic powder was prepared as the first component. In addition, the addition rate shown in Table 1 of the inorganic powder is shown by the concentration in the fiber defined above. Accordingly, the concentration of the inorganic powder only in the first component is higher than the concentration shown in the table (the concentration of the inorganic powder only in the first component can be easily calculated from the concentration in the fiber and the composite ratio). As the second component, a crystalline thermoplastic resin having the properties shown in Table 1 was prepared. In addition, the comparative example 4 is a single fiber of only a 2nd component, ie, a polypropylene. Each of these resin compositions was put into an individual 60 mmφ extruder, the extrusion temperature of the first component was the temperature shown in Table 1, and the extrusion temperature of the second component was 250 ° C. for polypropylene (of Comparative Example 4). In this case, when the second component is polyethylene terephthalate, the extrusion temperature is 280 ° C., and the total amount of both components is 2200 cc / min depending on the composite ratio of the first component and the second component. (Specifically, when the composite ratio A / B of the first component (A) and the second component (B) is 50/50, the extrusion rate of the first component is 1100 cc / min, Each component was extruded at a rate of 1100 cc / min), and each was melt-spun using a parallel-type, sheath-core type, or sheath-core eccentric type spinneret as described in the composite mode column of the table. As the spinneret, a circular spinner having a hole diameter of 0.35 mm and having 550 × 5 rows in the longitudinal direction of the spinneret was used. The fiber group discharged from the spinneret was introduced into an air soccer and pulled and drawn to obtain a long fiber group. Subsequently, the long fiber group discharged from the air soccer was charged by applying the same charge with a corona discharge device, and then opened by passing between a pair of vibrating blades. The unfolded long fiber group was collected as a long fiber fleece on an endless conveyor provided with a suction device on the back surface. At this time, the pulling speed of the air soccer was appropriately adjusted according to the type of the fibers so that the fineness of the long fibers was 2.2 d / f. Moreover, the density | concentration of the powder of the inorganic substance in a fiber was as showing in a table | surface. The collected long fiber fleece was transported while being placed on an endless conveyor, and was introduced between the pressurized rolls of a point bond processing machine constituted by a heated uneven roll and a smooth roll. In the introduced long fiber fleece, a long fiber nonwoven fabric in which the first component was melted or softened in a region corresponding to the convex portion of the concavo-convex roll and heat-bonded between the long fibers was obtained. The basis weight of this long fiber nonwoven fabric is 30 g / m.2So that the endless conveyor moving speed is 50 m / min. Was adjusted before and after. The circumferential speed of the uneven roll was the same as the moving speed of the endless conveyor. The linear pressure between the rolls and the roll temperature were set in the longitudinal direction of the bending resistance of the long-fiber nonwoven fabric (based on the 45 ° cantilever method of method A of JIS L 1096, but the sample size was 5 cm × 15 cm). The average value of the values in the horizontal direction was appropriately set so as to be around 35 mm.
[0049]
In addition, although all the nonwoven fabric formation (thermal fusion between long fibers) in an Example was performed by the point bond method for condition adjustment at the time of sensory tests, such as a feeling, a hot air heating method, a high-pressure water flow method, A needle punch method, an ultrasonic heating method, or the like may be used, and a combination of a plurality of these nonwoven fabric forming methods may be used.
[0050]
When polypropylene was used as the second component, one having an MFR (melt flow rate: measured under condition 14 of JIS K 7210 Table 1) of 35 was used. Further, when polyethylene terephthalate was used as the second component, the IV (intrinsic viscosity) value was 0.63 and the melting point was 255 ° C. The IV value was measured at 20 ° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent. Moreover, MI (melt index) of various polyethylene used for the first component is measured under condition 4 of JIS K 7210 Table 1.
[0051]
In addition, the average particle diameter of the inorganic substance described in Table 1 is 0.04 μm for silica, TiO.2 Is 0.20 μm, alum is 0.95 μm, CaCOThree0.08 μm, CaO 0.35 μm, MgO 0.17 μm, and talc 0.40 μm were used. TiO2 As this, rutile type titanium dioxide was used. In the table, PP as the second component means polypropylene, and PET means polyethylene terephthalate. Further, the volume ratio A / B in the column of the composite ratio indicates a numerical value of A for the first component and B for the second component, and is 100 for the entire composite fiber.
[0052]
The evaluation results of the long fiber nonwoven fabric obtained as described above are shown in Table 2.
In addition, the measuring method and evaluation criteria of each evaluation item are as follows.
(Adhesive strength with other materials <peeling strength>) The sample (long fiber nonwoven fabric) obtained in each of Examples and Comparative Examples and the sample to be bonded were each cut into a size of 10 cm × 5 cm. These samples are overlapped so that the four corners are aligned, and a heat seal elongated in the short side direction, that is, the width direction of the overlapped sample is applied. The position where the heat sealing is performed is a portion from a portion entering 1 cm inward in the longitudinal direction from one end of the short side of the overlapped sample to 2 cm inside. That is, a blank portion having no heat seal of 1 cm width was provided in parallel with the short side from one end of the short side of the sample, and a heat seal of 1 cm width was performed in parallel with the short side adjacent to the blank portion. The heat seal condition is a temperature of 150 ° C. (both up and down), 3 kg / cm2 , 5 seconds, and “Heat Seal Tester TP-701” (manufactured by Tester Sangyo Co., Ltd.) was used as the heat seal device.
[0053]
Tensilon tensile tester (“RDM-100”) was opened from the short side of the other end of the side not subjected to heat sealing, and the ends thereof were set at intervals of 10 cm. (Orientec Co., Ltd.) was fixed between the chucks so as not to twist. The peel strength was measured at a pulling speed of 100 mm / min, and the peel strength calculation method was in accordance with JIS L 1086-1983.
[0054]
(Bending softness) Measured in the vertical and horizontal directions in accordance with the 45 ° cantilever method of A method of JIS L 1096, and expressed as an average value. The sample size was 5 cm × 15 cm. In addition, as described above, the bending resistance was adjusted so as to be uniformly around 35 mm by performing the thermal fusion between the long fibers by the point bond method in order to adjust the conditions during the sensory test such as hand feeling. . Therefore, it is not described in Table 2.
[0055]
(Uniformity index of long-fiber non-woven fabric) Samples of 5 × 5 cm were collected at equal intervals of 5 points in the transverse direction of the non-woven fabric, cut into 1 cm squares, and weighed. From this, ((maximum value) − (minimum value)) × 100 / (average value) was calculated for each of the five samples, and the average value thereof was obtained. It was used as a scale for open and fine spots. It can be considered that the smaller this value is, the higher the uniformity is, and the uniformity is good at 80 or less.
[0056]
(Texture) Ten people performed a sensory test by touching the surface of the long-fiber non-woven fabric, and scored 1 point / one person when they felt soft and soft.
(Spinnability) Melt spinning was performed for 3 hours, and the number of occurrences of yarn breakage was measured. When the number of yarn breaks is 3 or less, it can be considered that the spinnability is good.
[0057]
(Measuring method of melting point)
Although it can measure using a DTA (differential thermal analysis) apparatus or a DSC (differential scanning calorimetry) apparatus, in the present invention, a DSC apparatus was used. And in this invention, what was measured with the following method was defined as melting | fusing point.
[0058]
Take approximately 0.4 mg of sample and weigh to the nearest 0.01 mg. As the sample container, an aluminum container having a uniform thickness and a purity of 99.9 to 99.99% is used. The sample is thinly placed in the center of the container, and is brought into close contact with the bottom surface of the sample container under constant pressure so that air does not enter the sample. The atmosphere gas uses nitrogen gas to remove oxygen and moisture. The heating rate was set to 10 ° C. per minute, and measurement was performed without subjecting the sample to specific treatment, such as once the sample was thermally melted in advance. The method for obtaining the melting point was in accordance with JIS K 7121-1987.
[0059]
[Table 1]
[Table 2]
In addition, the symbol used in Table 1 and Table 2 shows the following.
Abbreviations in Table 1
[0062]
PP: Isotactic polypropylene (MFR 35)
PET: Polyethylene terephthalate (IV 0.63, melting point 255 ° C.)
HDPE: High density polyethylene (MI 26)
LLDPE: Linear low density polyethylene (MI 30)
LDPE: Low density polyethylene (MI 35)
Abbreviations in Table 2
Copolymer: Ethylene-ethyl acrylate-maleic anhydride terpolymer (E-EA-MAH)
Here, E: ethylene, EA: ethyl acrylate, MAH: maleic anhydride
EH1: EA fraction 9.5 wt%, MAH fraction 2.5 wt%, melting point 102 ° C
EH2: EA fraction 21.9% by weight, MAH fraction 3.0% by weight, melting point 80 ° C.
EH3: EA fraction 22.9% by weight, MAH fraction 3.4% by weight, melting point 78 ° C.
EH4: EA fraction 29.4 wt%, MAH fraction 2.6 wt%, melting point 68 ° C
[0063]
In addition, the comparative example 4 has shown the long fiber nonwoven fabric which uses a high density polyethylene (sheath component) independently as a 1st component, and uses a sheath core type composite long fiber using a polypropylene (core component) as a 2nd component. .
[0064]
Absorption which consists of fluff pulp and superabsorbent resin which were wrapped in the backsheet which consists of the stretch film of the linear low density polyethylene, the cover which consists of tissue paper, and the long fiber nonwoven fabric of this invention obtained in Examples 1-9 A disposable diaper in which a core sheet, a second sheet, and a top sheet made of non-woven fabric heat-bonded by a through-air method consisting of short fibers of a sheath-core composite fiber whose core component is high-density polyethylene and whose core component is polypropylene are laminated in this order Used as a second sheet. In this case, the second sheet is thermally bonded to a cover (absorbing core layer cover) made of a cover sheet and tissue paper by a number of dot-like partial thermocompression processes. When the wearing test of the obtained disposable diaper was performed, the top sheet did not float, the top sheet did not clutter locally, there was no problem of clogging by the second sheet, the second sheet, the cover sheet, and the cover of the absorbent core layer A paper diaper with good adhesion was obtained.
[0065]
【The invention's effect】
Of the present inventionObtained by the spunbond methodThe long fiber nonwoven fabric contains 20% by weight or more of an ethylene-acrylic acid ester-maleic anhydride copolymer, and a first component in which at least a part of the fiber surface is formed in the fiber length direction; It consists of a heat-fusible composite continuous fiber having a crystalline thermoplastic resin having a melting point higher than that of the component as the second component, and contains an inorganic powder in at least the first component, and the content of the inorganic powder is adjusted to a concentration in the fiber. Since it contains 500 to 50000 ppm by weight, it is possible to provide a long-fiber nonwoven fabric that is excellent in high adhesiveness and low-temperature adhesiveness, has a good texture such as flexibility and touch, and is excellent in adhesion to different materials.Moreover, since the long fiber nonwoven fabric is a long fiber nonwoven fabric obtained by the spunbond method, a nonwoven fabric excellent in mechanical properties such as tensile strength can be easily obtained, and the long fiber obtained by melt spinning. As a nonwoven fabric is obtained by opening and accumulating as it is, the productivity is very excellent, and a nonwoven fabric having the above characteristics can be obtained at a relatively low cost. This is preferable because it can effectively improve the conventional defects of the composite long fiber nonwoven fabric obtained by the spunbond method.
[0066]
In the long fiber nonwoven fabric of the present invention, the copolymer composition of ethylene-acrylic acid ester-maleic anhydride copolymer has a maleic anhydride fraction of 2 to 5% by weight and an acrylic ester fraction of 6 to 30% by weight. %, The melting point is not too low and it is difficult to perform melt composite spinning, and the adhesiveness is not too high, satisfying the necessary properties as a material constituting the fiber surface. In addition, since the thermal stability is relatively good, there are few problems of thermal decomposition and alteration in melt spinning, and the thermal adhesiveness with other foreign materials is excellent, and the above effects can be exhibited more preferably. A long fiber nonwoven fabric can be provided and is preferable.
[0067]
Moreover, in the long fiber nonwoven fabric of the present invention, the preferred embodiment in which the melting point of the ethylene-acrylic acid ester-maleic anhydride copolymer is 60 to 110 ° C. makes it easy to spin and allows easy long fiber nonwoven fabric. It is also preferable because the long-fiber nonwoven fabric obtained has good adhesion.
[0068]
Further, in the long fiber nonwoven fabric of the present invention, polyethylene is used in combination with the preferred embodiment in which the resin component of the first component is a mixture of ethylene-acrylic acid ester-maleic anhydride copolymer and polyethylene. Thus, it is preferable that friction with a metal such as the air soccer football described above during melt spinning can be further reduced and adhesion between fibers can be more suitably prevented.
[0069]
Moreover, in the long-fiber nonwoven fabric of the present invention, the inorganic powder having an average particle diameter in this range is smaller by setting the particle diameter of the inorganic powder to a preferable aspect in which the average particle diameter is 0.04 to 2 μm. There is little increase in cost compared to those of particle size, secondary aggregation of inorganic powders, clogging of filters and spinning nozzles, thread breakage, and reduced operability, Compared with the case of using an inorganic powder with a larger particle size, the dispersibility of the inorganic powder may be poor, the filter or spinning nozzle may be clogged, and thread breakage may occur, resulting in a decrease in operability. Therefore, the above effect can be sufficiently achieved.
[0070]
Further, in the long fiber nonwoven fabric of the present invention, the inorganic powder is a preferred embodiment in which the inorganic powder is at least one inorganic powder selected from titanium dioxide, silica, alum, calcium carbonate, calcium oxide, magnesium oxide, and talc. Therefore, these inorganic powders have a relatively small nucleating action, and almost no increase in the crystallization temperature of the resin constituting the first component containing 20% by weight or more of ethylene-acrylic acid ester-maleic anhydride copolymer occurs. In addition, the increase in crystallinity is remarkably small. Therefore, the flexibility, high adhesiveness, low temperature adhesiveness, etc. of the resin having the low melting point or the low softening point as the first component are less likely to be impaired. It is preferable to obtain a long-fiber non-woven fabric having a good texture and the like and excellent adhesion to other foreign members.
[0071]
Further, in the long fiber nonwoven fabric of the present invention, it is preferable that a relatively flexible long fiber nonwoven fabric can be obtained by adopting a preferred embodiment in which the second component crystalline thermoplastic resin is polypropylene.
[0072]
In the long-fiber nonwoven fabric of the present invention, the second component crystalline thermoplastic resin is preferably made of polyethylene terephthalate, so that the strength is greater and the elasticity when crimping is expressed. A long fiber nonwoven fabric having better (cushioning properties) can be obtained, which is preferable.
[0074]
Moreover, the absorbent article of the present invention uses the long fiber nonwoven fabric for at least a part of the absorbent article, thereby improving the adhesiveness without causing clogging and the like, and constituting the absorbent article in use. An absorbent article free from problems caused by peeling or collapse of layers can be provided.
Claims (10)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25061197A JP3821256B2 (en) | 1996-11-22 | 1997-09-16 | Long fiber nonwoven fabric, method for producing the same, and absorbent article |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31234596 | 1996-11-22 | ||
| JP8-312345 | 1996-11-22 | ||
| JP25061197A JP3821256B2 (en) | 1996-11-22 | 1997-09-16 | Long fiber nonwoven fabric, method for producing the same, and absorbent article |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10204768A JPH10204768A (en) | 1998-08-04 |
| JP3821256B2 true JP3821256B2 (en) | 2006-09-13 |
Family
ID=26539833
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25061197A Expired - Fee Related JP3821256B2 (en) | 1996-11-22 | 1997-09-16 | Long fiber nonwoven fabric, method for producing the same, and absorbent article |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3821256B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101223305B1 (en) * | 2003-01-30 | 2013-01-16 | 다우 글로벌 테크놀로지스 엘엘씨 | Fibers formed from immiscible polymer blends |
| US20070122614A1 (en) * | 2005-11-30 | 2007-05-31 | The Dow Chemical Company | Surface modified bi-component polymeric fiber |
| CN114144550B (en) * | 2019-05-28 | 2024-03-12 | 东丽尖端素材株式会社 | Nonwoven fabric, method for producing same, article comprising same, and sanitary article using same |
| CN118996671B (en) * | 2024-09-30 | 2025-03-11 | 扬州石化有限责任公司 | A kind of low melting point ultra short fiber and preparation method thereof |
-
1997
- 1997-09-16 JP JP25061197A patent/JP3821256B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH10204768A (en) | 1998-08-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP7080251B2 (en) | Airlaid composite sheet material | |
| JP3216813B2 (en) | Long fiber nonwoven fabric and absorbent article using the same | |
| EP0896081B1 (en) | Fabrics formed of hollow filaments and fibers and methods of making the same | |
| WO1998056969A1 (en) | Nonwoven fabric of long fibers and absorbent articles made from the same | |
| KR102315690B1 (en) | Absorbents and hygiene products | |
| US5994244A (en) | Non-woven fabric comprising filaments and an absorbent article using the same | |
| JPH08504607A (en) | Absorbent article having a fusion layer | |
| JPH09117470A (en) | Absorbing article | |
| WO2015159978A1 (en) | Composite short fibers for absorbent article, process for producing same, thermally bonded nonwoven fabric for absorbent article, surface sheet for absorbent article, and absorbent article | |
| JP6899453B2 (en) | Composite long fiber non-woven fabric using eccentric sheath core type composite fiber on at least one side | |
| JPH0712367B2 (en) | Absorbent article | |
| JP6397210B2 (en) | Absorbent article surface sheet and absorbent article including the same | |
| JP5080074B2 (en) | Absorbent articles | |
| JP4587410B2 (en) | Composite nonwoven fabric, method for producing the same, absorbent article using the nonwoven fabric, and wiping cloth | |
| JP3949172B2 (en) | Long fiber nonwoven fabric, method for producing the same, and absorbent article using the same | |
| JP2001504723A (en) | Liquid impermeable sheet for absorbent articles | |
| JP3821256B2 (en) | Long fiber nonwoven fabric, method for producing the same, and absorbent article | |
| JP3697801B2 (en) | Long fiber nonwoven fabric and absorbent article using the same | |
| JPH10212651A (en) | Filament nonwoven cloth and absorbing material made thereof | |
| JP2647858B2 (en) | Absorbent articles | |
| JPH10212650A (en) | Filament nonwoven cloth and absorbing material made thereof | |
| JP3697805B2 (en) | Long fiber nonwoven fabric and absorbent article using the same | |
| JP6598951B2 (en) | Absorbent article surface sheet and absorbent article including the same | |
| JPH0375056A (en) | Facing of sanitary equipment | |
| JP2003247157A (en) | Absorbent body and absorbent article using the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20040413 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20060215 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20060320 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20060517 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20060601 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20060614 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100630 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100630 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110630 Year of fee payment: 5 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110630 Year of fee payment: 5 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313113 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110630 Year of fee payment: 5 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110630 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120630 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120630 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130630 Year of fee payment: 7 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |