JP3860465B2 - Powder fixed nonwoven fabric, production method thereof, and sheet material containing the same - Google Patents

Description

【００２５】
なお、粉体の平均粒径が５０μｍを越えていても、前述のような繊維ウエブにより粉体を保持することができる。
本発明における粉体の「平均粒径」は、コールターカウンター法により得られる値をいう。
【００２６】
このような粉体は前述のような繊維ウエブによって固着された状態にあるため、粉体固着不織布から粉体は脱落しない。この「固着された状態」とは、粉体が固定された状態を意味し、例えば、粉体の周囲を主として極細短繊維が包囲していることにより粉体を固定した状態、極細短繊維及び／又は後述する太繊維の融着によって粉体を固定した状態、あるいはこれら複数の要因によって粉体を固定した状態などをいう。
【００２７】
本発明による粉体固着不織布において、前述のような極細短繊維の質量比率は、粉体の平均粒径、比重、あるいは極細短繊維の繊維径によって異なるが、４０ｍａｓｓ％以下であれば、平均粒径５０μｍ以下程度の粒径の小さい粉体であっても脱落しないように保持することができ、２０ｍａｓｓ％以下でも殆ど粉体が脱落しない粉体固着不織布であることができ、１０ｍａｓｓ％以下でも実用上問題なく、かつ実用上取り扱いの際の強度的にも問題ない粉体固着不織布であることができる。他方、極細短繊維の質量比率が１ｍａｓｓ％以上であれば、粉体が脱落しにくく、実用的な取り扱い強度を有するものである。
【００２８】
本発明の粉体固着不織布においては、少なくとも、前述のような極細短繊維が分散しているため、極細短繊維を含んでいることによる効果を発揮することができる。この粉体固着不織布構成繊維における極細短繊維の含有量は、極細短繊維を含んでいることによる効果を発揮することができるように、２０ｍａｓｓ％以上であるのが好ましく、５０ｍａｓｓ％以上であるのがより好ましく、１００ｍａｓｓ％であるのが最も好ましい。
【００２９】
本発明の粉体固着不織布においては、前記の極細短繊維以外の繊維として、（１）繊維径が４μｍを越えるが繊維長が３ｍｍ以下の繊維（以下、太繊維と称する）、（２）繊維径が４μｍ以下であるが繊維長が３ｍｍを越える繊維（以下、長繊維と称する）、あるいは（３）繊維径が４μｍを越え、しかも繊維長が３ｍｍを越える繊維（以下、太長繊維と称する）を使用することができる。これらの中でも、繊維長が３ｍｍを越える長繊維及び太長繊維は分散性が悪く、極細短繊維の分散性を損なう場合があるため、繊維長が３ｍｍ以下の太繊維を使用するのが好ましい。
【００３０】
前記の太繊維を使用する場合、繊維径の上限は特に限定するものではないが、極細短繊維との繊維径の差が大きすぎると、粉体固着不織布の地合いを損ねる場合があるため、太繊維の繊維径の上限は５０μｍ程度であるのが好ましい。
なお、前記の太繊維も分散性に優れるように、２ｍｍ以下であるのが好ましい。下限は特に限定するものではないが、０．１ｍｍ程度が適当である。また、前記の太繊維も均一な長さであるように、３ｍｍ以下の長さに切断されたものであるのが好ましい。
【００３１】
この太繊維も極細短繊維と同様の成分から構成することができる。すなわち、例えば、ポリアミド系樹脂、ポリビニルアルコール系樹脂、ポリ塩化ビニリデン系樹脂、ポリ塩化ビニル系樹脂、ポリエステル系樹脂、ポリアクリロニトリル系樹脂、ポリオレフィン系樹脂（例えば、ポリエチレン系樹脂、ポリプロピレン系樹脂など）、ポリスチレン系樹脂（結晶性ポリスチレン、非晶性ポリスチレンなど）、全芳香族ポリアミド系樹脂、ポリウレタン系樹脂などの有機成分、ガラス、炭素、チタン酸カリウム、炭化珪素、窒化珪素、酸化亜鉛、ホウ酸アルミニウム、ワラストナイトなどの無機成分から構成することができる。
【００３２】
なお、前記の太繊維が融着可能な場合には、太繊維の融着によって本発明による粉体固着不織布の不織布形態を維持することができる。この融着可能な太繊維は、太繊維表面を構成する成分の少なくとも一部を熱可塑性樹脂から構成することができる。例えば、太繊維表面を構成する成分が、ポリオレフィン系樹脂（例えば、ポリエチレン系樹脂、ポリプロピレン系樹脂など）、ポリ塩化ビニリデン系樹脂、ポリエステル系樹脂、ポリアミド系樹脂、結晶性ポリスチレン系樹脂などの結晶性の熱可塑性樹脂、あるいはポリ塩化ビニル系樹脂、非晶性ポリスチレン系樹脂、ポリアクリロニトリル系樹脂、ポリビニルアルコール系樹脂などの非晶性の熱可塑性樹脂であることができる。これらの中でも、比較的融点の低いポリエチレン系樹脂や同じく比較的融点の低いポリ酢酸ビニル樹脂が好ましい。なお、ガラス繊維などの無機繊維や銅繊維などの金属繊維であることもできる。
【００３３】
この融着可能な太繊維が融点の異なる２種類以上の成分から構成されていると、１種類の成分が融着したとしても、少なくとも１種類の他の成分によって繊維形態を維持することができるため好適である。融着可能な太繊維が２種類以上の成分から構成されている場合、融着可能な太繊維の横断面形状は、例えば、芯鞘型、偏芯型、海島型、サイドバイサイド型、多重バイメタル型、又はオレンジ型であることができる。
また、この太繊維は未延伸状態であってもよいが、強度的に優れているように、延伸状態にあるのが好ましい。
【００３４】
本発明の粉体固着不織布に付着している付着物（界面活性剤や糊剤など）の付着率は、粉体が付着物によってその機能を損なうことがないように、０．５ｍａｓｓ％以下であるのが好ましい。この付着物の付着率が少なければ少ない程、粉体の機能を損なわないため、付着率は、好ましくは０．３ｍａｓｓ％以下、より好ましくは０．１ｍａｓｓ％以下、更により好ましくは０．０８ｍａｓｓ％以下、更により好ましくは０．０６ｍａｓｓ％以下、更により好ましくは０．０４ｍａｓｓ％以下、更により好ましくは０．０２ｍａｓｓ％以下である。このような付着物の低い付着率は、従来の湿式法によっては得ることのできないレベルである。なお、界面活性剤や糊剤の付着した湿式繊維ウエブ（粉体を含む）に対して、水流などを作用させたとしても、付着物の付着率を０．５ｍａｓｓ％以下とすることは困難である。
【００３５】
なお、本発明の粉体固着不織布において、付着物の付着率が低いと、粉体固着不織布使用中に付着物が脱離する危険性が極めて低いことによって、様々な好ましい効果をもたらす。例えば、一般的に、通常の不織布をフィルタとして使用した場合、濾過前の流体中に含まれている塵埃をフィルタで物理的に除去することができても、フィルタ（不織布）自体が汚染物質を発生すると、フィルタとしての役割が半減してしまう。これに対して、本発明の粉体固着不織布、あるいは、前記粉体固着不織布層少なくとも１層を含有する本発明によるシート材料は、付着物量が少なく、付着物が脱離する可能性が極めて低いため、フィルタとして好適に使用することができる。
【００３６】
この付着物の付着率は、粉体固着不織布の質量に対する付着物の質量の百分率をいう。すなわち、次の式（１）：
Ａ＝（ｍｓ／ｍｆ）×１００ （１）
〔ここで、Ａは付着物の付着率（％）、ｍｓは付着物の付着質量（ｇ）、ｍｆは粉体固着不織布の質量（ｇ）を、それぞれ意味する〕
により得られる値をいう。
また、本明細書における「付着物」には、粉体固着不織布を熱水（例えば、８０〜１００℃の水）に１５分間浸漬することによって得られる抽出物（以下、熱水抽出物と称する）、及び粉体固着不織布を熱メタノール溶液に１５分間浸漬することによって得られる抽出物（以下、熱メタノール抽出物と称する）の両方が含まれる。熱水抽出物として、糊剤（例えば、アクリルアミド、ポリアクリル酸ソーダ、ポリアルギン酸ソーダ、ポリエチレンオキサイド、メチルセルロース、カルボキシメチルセルロース、ヒドロキシメチルセルロース、ポリビニルアルコールなど）があり、熱メタノール抽出物として、界面活性剤（親水基と親油基の両方を有する化合物、例えば、ノニオン系界面活性剤）がある。
【００３７】
本発明の粉体固着不織布は、この不織布を構成している繊維（極細短繊維、太繊維など）及び／又は粉体が融着しているのが好ましい。このように融着していると、この融着によって更に粉体が脱落しにくいためである。
【００３８】
本発明の粉体固着不織布は、１層である必要はなく、粉体が固着し、極細短繊維が分散した層を２層以上含んでいることができる。粉体が固着し、極細短繊維が分散した層２層以上を備えていると、様々な特性を付与することができる。例えば、イオン交換樹脂粉末が固着している粉体固着不織布層と脱臭剤粉末が固着している粉体固着不織布層とを備えた粉体固着不織布はイオン交換性能と脱臭性能とを併せ持つものである。
【００３９】
本発明の粉体固着不織布は、前述のような粉体が固着した粉体固着不織布層のみから構成されていても、粉体が脱落しにくい十分実用的なものであるが、粉体が微量でも脱落してはいけない場合には、前述のような粉体が固着した粉体固着不織布層の粉体が脱落してはいけない面側（少なくとも片面）に、粉体不含層、例えば、粉体の脱落を防止することのできる脱落防止層を更に備えているのが好ましい。
【００４０】
この脱落防止層は、粉体の脱落を防止する機能を有する限り、特に限定されるものではないが、粉体固着不織布層を構成する極細短繊維と繊維径が同じか、それよりも繊維径の細い極細短繊維（すなわち、繊維径が４μｍ以下）を含む繊維ウエブに由来する不織布であるのが好ましい。もっとも、繊維径は、固着されている粉体の平均粒径によっても異なる。この不織布は、例えば、極細短繊維の融着によって不織布形態を維持している。このような不織布は、例えば、後述のような粉体固着不織布層を形成する際に、粉体を供給しない方法により製造することができるし、極細短繊維を通常の湿式法により繊維ウエブを形成した後、極細短繊維の融着性を利用したり、水流などの流体流により絡合したり、あるいはこれらを併用して製造することもできる。
【００４１】
また、粉体の平均粒径によっては、メルトブロー法により得られる不織布や、機械的に分割可能な繊維を含む繊維ウエブを乾式法又は湿式法により形成した後、水流などの流体流によって絡合させた不織布などを脱落防止層として使用することができる。
【００４２】
この脱落防止層の目付は脱落防止層を構成する繊維、構造、粉体の平均粒径などによって異なるため、特に限定されるものではないが、目付が１ｇ／ｍ²以上であれば、実用的に全く問題のない脱落防止層となりうる。
【００４３】
本発明の粉体固着不織布は、極細短繊維及び粉体を含んでいることによる各種特性に優れているため、本発明の粉体固着不織布の形態で、あるいは、前記粉体固着不織布層少なくとも１層を含むシート材料の形態で、例えば、電子写真装置用、トイレ用脱臭用、又はオゾン発生装置用などのオゾン分解用シート；イオン交換水精製機などのイオン交換用シート；自動車用、又は化学反応装置用などの触媒用シート；生活用品用、生理用品用、フィルタ用、又は靴用などの脱臭又は消臭シート；繊維強化プラスチック（ＦＲＰ）やシート状プリプレグ（ＳＭＣ）；あるいは耐火ボードなどの各種用途に使用することができる。
【００４４】
本発明の粉体固着不織布は、例えば次の方法によって製造することができる。
まず、前記の粉体と、繊維径が４μｍ以下で繊維長が３ｍｍ以下の極細短繊維の集合体（特には、束状の集合体）若しくはそれらの集合体群（特には、複数の束状集合体を束状で含む集合体群）、及び／又は、機械的に分割して繊維径が４μｍ以下で繊維長が３ｍｍ以下の極細短繊維を発生可能な分割性繊維、若しくはそれらの集合体（特には、束状の集合体）を準備する。なお、前記極細短繊維集合体若しくはそれらの集合体群、及び／又は、極細短繊維発生可能分割性繊維若しくはそれらの集合体として、付着物（界面活性剤、又は糊剤など）の付着率が０．５ｍａｓｓ％以下（好ましくは０．３ｍａｓｓ％以下、より好ましくは０．１ｍａｓｓ％以下、更により好ましくは０．０８ｍａｓｓ％以下、更により好ましくは０．０６ｍａｓｓ％以下、更により好ましくは０．０４ｍａｓｓ％以下、更により好ましくは０．０２ｍａｓｓ％以下）の前記極細短繊維集合体若しくはそれらの集合体群、及び／又は、極細短繊維発生可能分割性繊維若しくはそれらの集合体を使用すると、本発明の粉体固着不織布の製造が容易になる。
【００４５】
この付着物の付着率の少ない極細短繊維集合体若しくはそれらの集合体群、又は、極細短繊維発生可能分割性繊維若しくはそれらの集合体は、例えば、繊維径が４μｍ以下で繊維長が３ｍｍ以下の市販極細短繊維集合体若しくはそれらの集合体群、又は、極細短繊維発生可能分割性繊維若しくはそれらの集合体を用意した後、アセトンなどの溶媒により、付着物の付着率が０．５ｍａｓｓ％以下となるまで洗浄して得ることができる。あるいは、付着物の付着率の少ない極細短繊維集合体若しくはそれらの集合体群は、例えば、複合紡糸法や混合紡糸法により製造した海島型繊維又は海島型繊維の群の海成分を、抽出除去して得ることができる。また、海島型繊維から海成分を抽出除去した後に、アセトンなどの溶媒により洗浄すれば、より付着物量を少なくすることができる。なお、付着物を除去すると、極細短繊維表面に静電気が発生しやすくなり、極細短繊維が相互に反発して分散しやすくなる。
【００４６】
なお、極細短繊維集合体若しくはそれらの集合体群中の極細短繊維が絡んだ状態にあると、後述のような圧縮気体の作用によっても、極細短繊維を均一に分散させるのが困難になる傾向があったり、圧縮気体を何度も作用させる必要が生じるため、極細短繊維集合体若しくはそれらの集合体群中の極細短繊維は絡んだ状態にないのが好ましい。例えば、機械的に分割可能な分割性繊維をビーターなどによって叩解した極細短繊維集合体や、ビーターなどによって叩解したパルプや、あるいはフラッシュ紡糸法により得られた極細短繊維集合体などは、極細短繊維同士が絡んだ状態にあるため使用しないのが好ましい。なお、圧縮気体の作用によって機械的に分割して、繊維径が４μｍ以下で繊維長が３ｍｍ以下の極細短繊維を発生可能な極細短繊維発生可能分割性繊維若しくはそれらの集合体（例えば、全芳香族ポリアミド短繊維若しくはそれらの集合体、溶剤抽出法により得られたセルロース短繊維若しくはそれらの集合体など）は使用することができる。また、前記の太繊維若しくはそれらの集合体を使用する場合も、アセトン洗浄などを予め実施して付着物の付着率の少ない状態とするのが好ましい。
【００４７】
次いで、前述のような前記極細短繊維集合体若しくはそれらの集合体群、及び／又は、極細短繊維発生可能分割性繊維若しくはそれらの集合体（場合により、更に太繊維若しくはそれらの集合体）を、前述のような粉体と共に、ノズルへ供給するとともに、それらに圧縮気体を作用させることにより、ノズルから気体中に噴出させ、前記極細短繊維集合体若しくはそれらの集合体群から極細短繊維に分割し、それらの極細短繊維を分散させ、及び／又は極細短繊維発生可能分割性繊維若しくはそれらの集合体から極細短繊維を発生させ、それらの極細短繊維を分散させる。なお、太繊維若しくはそれらの集合体を含んでいる場合には、太繊維を分散させるか、あるいは集合体から太繊維を分割し、そして分散させる。それらの分散と共に、前述のような粉体も同時に分散させる。
【００４８】
ノズルへ供給する気体の流れが実質的に層流であるのが好ましい。層流であると、極細短繊維同士の絡みが生じにくいため、極細短繊維が分散しやすくなる。一般的に、ノズル中を通過する繊維の繊維径が４μｍ以下（特には２μｍ以下）と細く、剛性が低い（柔らかい）場合、束状の極細短繊維集合体若しくはそれらの集合体群（特に、海島型繊維の島成分から誘導される束状極細短繊維集合体若しくはそれらの集合体群）の場合、あるいは極細短繊維が有機成分からなり剛性が低い（柔らかい）場合には、絡みやすくなる。しかし、このような場合でも、ノズルへ供給する気体の流れを実質的に層流とすることによって、絡みを抑制することができる。なお、ノズルとしてベンチュリー管を使用することにより、ノズルを通過する気体の流れを実質的に層流とすることができる。
【００４９】
このノズルは、前記粉体と、前記極細短繊維集合体などの供給側から噴出側に向かって（流れ方向に）、一定の横断面積を有するものであることもできるが、流れ方向に連続的に又は不連続的に横断面積が小さくなるか大きくなるものであることも、流れ方向に連続的に又は不連続的に横断面積が大きくなった後に小さくなるように変化するものであることも、あるいは流れ方向に連続的に又は不連続的に横断面積が小さくなった後に大きくなるように変化するものであることもできる。また、前記ノズル噴出口から噴出させた前記粉体、並びに束状の極細短繊維集合体（若しくはそれらの集合体群）及び／又は極細短繊維発生可能繊維（若しくはそれらの集合体）を、前記ノズル噴射口の前方に設けられた衝突部材（例えば、邪魔板）に衝突させ、前記粉体、並びに束状の極細短繊維集合体若しくはそれらの集合体群及び／又は極細短繊維発生可能分割性繊維（若しくはそれらの集合体）からの極細短繊維の発生効率及び発生した極細短繊維の分散効率を向上させることができる。特に、ノズルへ供給する気体の流れを実質的に層流とする場合には、粉体及び極細短繊維を分割し分散させる作用が乏しいため、衝突部材（例えば、邪魔板）を設けて分散を促進するのが好ましい。
【００５０】
圧縮気体としては任意の気体を利用することができ、空気を用いるのが粉体固着不織布の製造上好適である。また、圧縮気体は、粉体を分散させるとともに、前記極細短繊維集合体若しくはそれらの集合体群を充分に分散することができ、及び／又は極細短繊維発生可能分割性繊維若しくはそれらの集合体を極細短繊維に分割して充分に分散させることができるように、ノズルの噴出口における気体通過速度が１００ｍ／ｓｅｃ以上であるのが好ましい。この「気体通過速度」は、ノズルから噴出された気体の１気圧における流量（ｍ³／ｓｅｃ）を、ノズル噴出口における横断面積（ｍ²）で除した値をいう。また、圧縮気体の圧力は、粉体を分散させるとともに、前記極細短繊維集合体若しくはそれらの集合体群を充分に分散、及び／又は極細短繊維発生可能分割性繊維若しくはそれらの集合体を極細短繊維に分割し、充分に分散させることができるように、２ｋｇ／ｃｍ²以上であるのが好ましい。
【００５１】
また、ノズルから噴出された粉体を分散させるとともに、前記極細短繊維集合体若しくはそれらの集合体群を極細短繊維に分割し、充分に分散し、及び／又は極細短繊維発生可能分割性繊維若しくはそれらの集合体を極細短繊維に分割し、充分に分散させる分散媒体としての気体は、特に限定されるものではないが、空気であるのが粉体固着不織布の製造上好適である。
【００５２】
なお、前記極細短繊維集合体若しくはそれらの集合体群、及び／又は、極細短繊維発生可能分割性繊維若しくはそれらの集合体における付着物の付着率が低いと、ノズルとそれらとの摩擦によって静電気が発生しやすく、極細短繊維同士が反発しあって、より分散した状態で集積できる、という効果を奏する。
【００５３】
次いで、この分散した粉体及び分散した極細短繊維（場合により、分散した太繊維も含む）を集積して、粉体含有繊維ウエブを形成する。この粉体及び極細短繊維の集積は、例えば、多孔性のロールやネットなどの支持体を利用して実施することができる。なお、粉体及び極細短繊維は自然落下させて集積することができ、あるいは支持体の下方から気体を吸引して集積することができる。後者の場合、吸引力を強くすると、粉体と極細短繊維とが密着した状態の粉体含有繊維ウエブとすることができ、吸引力を弱くすると、比較的嵩高な粉体含有繊維ウエブとすることができる。
【００５４】
なお、本発明においては、この粉体含有繊維ウエブの全質量に対する極細短繊維の質量比率を１〜４０ｍａｓｓ％とすることができるため、粉体量が多く、粉体の機能を十二分に発揮することができる。このような極細短繊維と粉体の量の調整は、粉体と極細短繊維集合体若しくはそれらの集合体群及び／又は極細短繊維発生可能分割性繊維若しくはそれらの集合体のノズルへの供給量を調節することにより実施することができる。
【００５５】
次いで、この粉体含有繊維ウエブ中に含まれている粉体を固着させて、本発明の粉体固着不織布を製造することができる。この固着方法は特に限定されるものではないが、例えば、繊維（極細短繊維及び／又は太繊維）及び／又は粉体を融着させる方法を挙げることができる。
【００５６】
以上は、本発明の粉体固着不織布の基本的な製造方法であるが、粉体及び極細短繊維が均一に分散しやすいように、粉体と前記極細短繊維集合体若しくはそれらの集合体群、及び／又は、極細短繊維発生可能分割性繊維の集合体を圧縮気体の作用によりノズルから気体中へ噴出させる前に、ミキサーなどを利用してより本数の少ない極細短繊維集合体（又は集合体群）及び／又は、より本数の少ない極細短繊維発生可能分割性繊維の集合体に小分けしたり、分散させたり、混合するのが好ましい。
【００５７】
また、粉体含有繊維ウエブを形成した後、粉体を固着させる前に、粉体含有繊維ウエブを、同じ又は異なるノズルに再度供給し、粉体及び極細短繊維をノズルから気体中に噴出させて再分散させ、粉体含有繊維ウエブを形成することを繰り返し行うことができる。
【００５８】
なお、繊維径の点において異なる、２種類以上の極細短繊維、及び／又は太繊維を含む粉体固着不織布が得られるように、前記極細短繊維集合体若しくはそれらの集合体群、又は、極細短繊維発生可能分割性繊維若しくはそれらの集合体、及び／又は太繊維集合体を併用することができる。
また、繊維径の点において異なる極細短繊維を含む繊維集合体若しくはそれらの集合体群、繊維径の点において異なる極細短繊維を発生可能な分割性繊維若しくはそれらの集合体及び／又は繊維径の点において異なる太繊維、若しくはそれらの集合体の配合量を、連続的に又は不連続的に変化させながらノズルへ供給することもできる。このように変化させると、繊維径の違いによって、見掛密度の異なる層又は領域を、厚さ方向に有する粉体固着不織布を製造することができる。また、平均粒径及び／又は組成の点で異なる２種類以上の粉体の配合量を、連続的に又は不連続的に変化させながらノズルへ供給することもできる。
【００５９】
前述のような好適である脱落防止層を備えている粉体固着不織布、あるいは、粉体固着不織布層と脱落防止層とを含む本発明のシート材料は、例えば、最初に、極細短繊維の集合体（特には、束状の集合体）若しくはそれらの集合体群（特には、複数の束状集合体を束状で含む集合体群）、及び／又は、機械的に分割して前記の極細短繊維を発生可能な分割性繊維、若しくはそれらの集合体（特には、束状の集合体）を、粉体を含まない条件下で、前述の方法と同様に圧縮気体の作用によりノズルから気体中に噴出させ、集積させて、極細短繊維からなる繊維ウエブを形成した後、極細短繊維の融着性を利用したり、水流などの流体流により絡合したり、あるいはこれらを併用して脱落防止層である不織布を形成した後、前述と同様の方法によって、この不織布上に粉体及び極細短繊維を集積させた後、粉体を固着して製造することができる。なお、粉体が固着した層の両側に極細短繊維からなる不織布（脱落防止層）を配置する場合には、続いて、前記脱落防止層である不織布を形成する方法と同様にして、粉体が固着した層の上に、脱落防止層である不織布を形成することによって製造することができる。
【００６０】
また、極細短繊維から通常の湿式法により繊維ウエブを形成した後、極細短繊維の融着性を利用したり、水流などの流体流により絡合したり、あるいはこれらを併用して製造した不織布や、メルトブロー法により得られる不織布や、機械的に分割可能な繊維を含む繊維ウエブを乾式法又は湿式法により形成した後、水流などの流体流によって絡合させた不織布などを用意した後、これら脱落防止層として作用する不織布の上に、前述と同様の方法によって、この不織布上に粉体及び極細短繊維を集積させた後、粉体を固着して製造することができる。なお、粉体が固着した層の両側に不織布（脱落防止層）を配置する場合には、前記脱落防止層を構成する不織布と同様の不織布を積層一体化することにより製造することができる。
なお、粉体が固着した層の両側に脱落防止層を配置する場合には、両方の脱落防止層が同じ構造及び材料であっても、異なる構造及び材料であってもよい。
【００６１】
なお、分散した極細短繊維及び分散した粉体を集積して粉体含有繊維ウエブを形成する際に、分散した極細短繊維及び分散した粉体を補強材（例えば、糸、ネット、織物、編物、繊維ウエブ、又は通常の不織布など）の上に集積させて、積層体を形成することもできる。このように積層体とすることにより、粉体固着不織布の強度を向上させることができるため、本発明の粉体固着不織布を強度を必要とする用途に適用することができる。なお、本発明による粉体固着不織布を形成した後に、その粉体固着不織布を前記のような補強材（例えば、糸、ネット、織物、編物、繊維ウエブ、通常の不織布、又はフィルムなど）と一体化して積層体とすることによって、同様の効果を奏することができる。
【００６２】
次に、本発明の粉体固着不織布の製造に用いることのできる製造装置について、その具体的態様を示す図１に沿って説明する。なお、繊維径が４μｍ以下で繊維長が３ｍｍ以下の極細短繊維の集合体（特に束状集合体）を用いる場合について説明する。図１は、本発明で用いる粉体固着不織布製造装置の１態様の模式的説明図である。
【００６３】
まず、粉体と、繊維径が４μｍ以下で繊維長が３ｍｍ以下の極細短繊維の束状集合体を、場合により太繊維若しくはそれらの集合体と共に、ミキサーなどの混合装置１０に装入して、その中で束状集合体を、より小さい束状集合体に分割したり、極細短繊維を分散させたり、解したり、あるいは混合する。
【００６４】
次いで、この解したり、あるいは粉体と混合された極細短繊維及び／又は束状の極細短繊維集合体（場合により太繊維及び／又はその集合体も）は、混合装置１０から供給管１１を介してノズル３０へ供給される。移送には、混合装置１０に設けた搬送用気体供給装置（図示せず）から供給される適当な搬送用気体を用いることもできる。供給管１１へは、ノズル３０の手前で、圧縮気体導入口２０から圧縮気体が導入される。この圧縮気体の作用によって、前記の束状の極細短繊維集合体（場合により太繊維及び／又はその集合体も）は、粉体と共に、混合装置１０から供給管１１を介してノズル３０へ移動し、更にノズル３０から勢いよく、分散室４０内の気体４０ａ中へと噴出される。この気体４０ａへ噴出される際に、ノズル３０内と気体４０ａとの気圧差、及び噴出された圧縮気体と気体４０ａとの間に形成される乱流などの相互作用によって、束状の極細短繊維集合体から極細短繊維７０が発生し、粉体７０ａと共に、分散室４０内で分散する。更に、ノズル３０から噴出した極細短繊維７０及び粉体７０ａを分散室４０の壁部４５に衝突させることによって極細短繊維７０の分割及び分散を促進し、粉体７０ａの分散を促進することもできる。この場合、前記壁部４５は、衝突部材として作用することができる。また、前記ノズル３０の噴出口と前記壁部４５との間に、別途に衝突部材を設けることもできる。前記ノズル３０の噴出口と衝突部材の平坦部（衝突部）との距離は好ましくは１〜１００ｍｍ、より好ましくは５〜４０ｍｍ、より好ましくは５〜３０ｍｍ、より好ましくは１０〜３０ｍｍ、最も好ましくは１０〜２０ｍｍである。
【００６５】
分散室４０内の気体４０ａ中に分散した極細短繊維７０及び粉体７０ａは、分散室４０内を降下し、分散室４０の底部に設けたネットからなる支持体５０上に集積して粉体含有繊維ウエブ８０を形成する。本発明で用いる製造装置においては、図１に示すとおり、分散室４０の底部の支持体５０の下方に気体吸引装置６０を設けることができ、この気体吸引装置６０によって分散室４０内の気体４０ａを吸引し、極細短繊維７０及び粉体７０ａの集積を促進することができる。分散室４０の内部と分散室４０の外側とは、気密にすることができるし、気密にしないこともできる。
【００６６】
また、粉体含有繊維ウエブ８０を集積する支持体５０はエンドレスベルト状で回転し、供給管１２，１３の方向（図１の矢印ａの方向）へ粉体含有繊維ウエブ８０を搬送する。続いて、粉体含有繊維ウエブ８０は、供給管１２及び１３を介して、再度、ノズル３１，３２へ供給される。図１に示す態様のように、２つのノズルに再供給することができるだけでなく、１つのノズルに再供給するか、あるいは３つ以上のノズルに再供給することもできる。あるいは、充分な分散が行われている場合には、後述する熱融着装置９０へ移送して結合工程に直接に送ることもできる。
【００６７】
前記の供給管１２及び１３においても、ノズル３１，３２の手前で、それぞれ、圧縮気体導入口２１，２２から圧縮気体が導入されるので、この圧縮気体の作用によって、粉体含有繊維ウエブ８０から供給される極細短繊維（場合により太繊維も）及び粉体が、供給管１２，１３を介してノズル３１，３２へ移動し、更にノズル３１，３２から勢いよく、分散室４１，４２内の気体４１ａ，４２ａ中へと噴出される。この際に、同様に極細短繊維７１，７２及び粉体７１ａ，７２ａは均一に分散する。更に、各ノズル３１，３２から噴出した極細短繊維７１，７２及び粉体７１ａ，７２ａを分散室４１，４２の壁部４６，４７に衝突させることによって分散を促進することもできる。この場合、前記壁部４６，４７は、衝突部材として作用することができる。また、前記ノズル３１，３２の噴出口と前記壁部４６，４７との間に、別途に衝突部材を設けることもできる。
【００６８】
分散室４１，４２内の気体４１ａ，４２ａ中に分散した極細短繊維７１，７２及び粉体７１ａ，７２ａは、それぞれ分散室４１，４２内を降下し、分散室４１，４２の底部に共通して設けたネットからなる支持体５１上に集積する。すなわち、分散室４１内の気体４１ａ中に分散した極細短繊維７１及び粉体７１ａは、分散室４１内を降下して支持体５１上に集積して単層粉体含有繊維ウエブ８１を形成した後、エンドレスベルト状の支持体５１と共に、分散室４２の方向（図１の矢印ｂの方向）へ搬送される。また、分散室４２内の気体４２ａ中に分散した極細短繊維７２及び粉体７２ａは、分散室４２内を降下して、支持体５１上の単層粉体含有繊維ウエブ８１の上に更に集積して積層粉体含有繊維ウエブ８２を形成する。もっとも、こうして形成される積層粉体含有繊維ウエブ８２は、単層の粉体含有繊維ウエブ８０を構成する極細短繊維を再度分散させているため、明確な２層構造が存在するものではない。
【００６９】
本発明で用いる製造装置においては、図１に示すとおり、分散室４１，４２の底部の支持体５１の下方にも気体吸引装置６１を設けることができ、この気体吸引装置６１によって分散室４１，４２内の気体４１ａ，４２ａを吸引し、極細短繊維７１，７２及び粉体７１ａ，７２ａの集積を促進することができる。また、支持体５１及び気体吸引装置６１は、図１に示すとおり、複数の分散室に対して共通に設けることもでき、あるいは複数の分散室のそれぞれに対して独立に別個に設けることもできる。
【００７０】
次いで、エンドレスベルト状の支持体５１により、この積層粉体含有繊維ウエブ８２を熱融着装置９０へと搬送し、この熱融着装置９０にて熱の作用により極細短繊維及び／又は粉体、及び場合により太繊維が融着して粉体固着不織布８３を形成することができる。そして、この粉体固着不織布８３は巻き取り装置１００により巻き取られる。
【００７１】
本発明によるシート材料は、前記の粉体固着不織布層少なくとも１層を含有する。すなわち、本発明によるシート材料は、前記の粉体固着不織布層の単独層からなるか、あるいは前記の粉体固着不織布層１層又はそれ以上と別の粉体脱落防止層１層又はそれ以上（好ましくは１層又は２層）、又は、１層又はそれ以上の補強層を含む。補強層としては、通常の糸層、ネット層、織物層、編物層、繊維ウエブ層、又は通常の不織布層などを挙げることができる。前記の粉体固着不織布層と補強層を含むシート材料は、例えば、補強層の上に粉体含有繊維ウエブを集積し、粉体含有繊維ウエブと補強層とを結合して粉体固着不織布層を形成すると同時に製造するか、あるいは補強層と粉体固着不織布層とを適当な結合手段によって結合して製造することができる。
本発明によるシート材料は、前記の粉体固着不織布層を含有するので、粉体の有する各種特性を利用する分野に有利に用いることができる。例えば、電子写真装置用、トイレ用脱臭用、又はオゾン発生装置用などのオゾン分解用シート；イオン交換水精製機などのイオン交換用シート；自動車用、又は化学反応装置用などの触媒用シート；生活用品用、生理用品用、フィルタ用、又は靴用などの脱臭又は消臭シート；繊維強化プラスチック（ＦＲＰ）やシート状プリプレグ（ＳＭＣ）；あるいは耐火ボードなどの各種用途に使用することができる。
【００７２】
【実施例】
以下、実施例によって本発明を具体的に説明するが、これらは本発明の範囲を限定するものではない。
【実施例１】
ポリ乳酸からなる海成分中に、ポリプロピレンからなる島成分が２５個存在し、複合紡糸法により得た海島型繊維（繊度＝１．７ｄｔｅｘ；繊維長１ｍｍに切断されたもの）を用意した。この海島型繊維を１０ｍａｓｓ％水酸化ナトリウム水溶液中に浸漬して、海成分であるポリ乳酸を加水分解により抽出除去した後、風乾して、ポリプロピレン極細短繊維（繊維径＝２μｍ；繊維長＝１ｍｍ；フィブリル化していない；延伸されている；繊維軸方向において実質的に同じ直径を有する；付着物の付着率＝０．０２ｍａｓｓ％未満）が束状となった極細短繊維Ａの集合体を得た。
【００７３】
また、ポリ乳酸からなる海成分中に、高密度ポリエチレンとポリプロピレンとからなる島成分が２５個存在し、複合紡糸法により得た海島型繊維（繊度＝１．７ｄｔｅｘ；繊維長１ｍｍに切断されたもの）を用意した。この海島型繊維を１０ｍａｓｓ％水酸化ナトリウム水溶液中に浸漬して、海成分であるポリ乳酸を加水分解により抽出除去した後、風乾して、高密度ポリエチレン中にポリプロピレンが点在した海島型極細短繊維（繊維径＝２μｍ；繊維長＝１ｍｍ；フィブリル化していない；延伸されている；繊維軸方向において実質的に同じ直径を有する；付着物の付着率＝０．０２ｍａｓｓ％未満）が束状となった海島型極細短繊維Ｂの集合体を得た。
【００７４】
更に、粉体として、平均粒径が６μｍの活性炭を用意した。
【００７５】
次いで、図１に示す製造装置と同様の装置を用いて、本発明による粉体固着不織布を調製した。すなわち、束状の極細短繊維Ａ集合体、束状の海島型極細短繊維Ｂ集合体、及び活性炭を、１０：５：８５の質量比でミキサーに供給して、これらを解すとともに混合した後、噴出口における横断面形状が円形（直径＝８．５ｍｍ）のベンチュリー管〔ベンチュリー管の供給側における横断面形状＝円形（直径＝３ｍｍ）の円錐台状〕に供給するとともに、ベンチュリー管の手前に設けられた圧縮気体導入口から層流の圧縮空気（圧力＝６ｋｇ／ｃｍ²）を導入して、前記ベンチュリー管から前記混合物を空気中に噴出（ベンチュリー管の噴出口における気体通過速度＝１１８ｍ／ｓ）し、前記ベンチュリー管の噴出口前方に設けた邪魔板に衝突させて、活性炭、並びにポリプロピレン極細短繊維Ａ及び海島型極細短繊維Ｂを分散させた。前記ベンチュリー管の噴出口と邪魔板との距離は１５ｍｍであった。
【００７６】
次いで、この分散させた活性炭、ポリプロピレン極細短繊維及び海島型極細短繊維を、ネットからなる支持体上に載置しておいた不織布基材（目付が３０ｇ／ｍ²のポリエステル繊維製スパンボンド不織布）上に集積させた。なお、集積させる際には、支持体の下に設置されたサクションボックスにより空気を吸引（２ｍ³／ｍｉｎ）した。
【００７７】
次いで、この粉体含有繊維ウエブを担持するスパンボンド不織布基材を、温度１３０℃に設定されたオーブンに供給し、３分間熱処理を実施して、目付７０ｇ／ｍ²、厚さ１．２ｍｍの不織布基材積層粉体固着不織布を製造した。この不織布基材積層粉体固着不織布の粉体固着不織布層は、ポリプロピレン極細短繊維Ａ及び海島型極細短繊維Ｂが活性炭粉末の周囲を囲むように絡合しているとともに、海島型極細短繊維Ｂを構成する高密度ポリエチレン成分によって、ポリプロピレン極細短繊維Ａと海島型極細短繊維Ｂ、及び海島型極細短繊維Ｂと活性炭粉末とが融着した状態にあった。
【００７８】
なお、こうして得られた不織布基材積層粉体固着不織布から不織布基材を剥離し、粉体固着不織布のみについて各種物性を測定したところ、目付は４０ｇ／ｍ²、厚さは１．１ｍｍ、見掛密度は０．０３６ｇ／ｃｍ³で、極細短繊維Ａ，Ｂの質量比率は１５ｍａｓｓ％であった。また、この粉体固着不織布を熱水中に１５分間浸漬して抽出した付着物と、熱メタノール中に１５分間浸漬して抽出した付着物との総付着物質量の、粉体固着不織布の質量に対する百分率（付着物の付着率）は０．０２ｍａｓｓ％未満であった。
【００７９】
この不織布基材積層粉体固着不織布をプリーツ加工したフィルターユニット（山高さ＝２０ｍｍ，ピッチ＝２ｍｍ）を作成し、トルエンを２５ｐｐｍの濃度で含む空気を面風速１４ｃｍ／ｓｅｃ．で通過させたところ、フィルターユニット出口におけるトルエンの除去率は９９％以上の高い脱臭性能を示した。また振動を与えても不織布基材積層粉体固着不織布からの活性炭の脱落は観察されなかった。
【００８０】
【実施例２】
実施例１と同様にして製造した束状の極細短繊維Ａ集合体、束状の海島型極細短繊維Ｂ集合体を用意した。また、粉体として電解質二酸化マンガン粉末（平均粒径＝３μｍ）を用意した。
【００８１】
次いで、実施例１と同様に、図１に示す製造装置と同様の装置を用いて、本発明による粉体固着不織布を調製した。すなわち、束状の極細短繊維Ａ集合体、束状の海島型極細短繊維Ｂ集合体、及び電解質二酸化マンガン粉末を、６：９：８５の質量比でミキサーに供給して、これらを解すとともに混合した後、これら混合物を、噴出口における横断面形状が円形（直径＝３．２ｍｍ）で連続的に先細りの先細ノズルに供給するとともに、先細ノズルの手前に設けられた圧縮気体導入口から層流の圧縮空気（圧力＝６ｋｇ／ｃｍ²）を導入し、前記先細ノズルから前記混合物を分散室の空気中に噴出（先細ノズルの噴出口における気体通過速度＝１６００ｍ／ｓ）して、ポリプロピレン極細短繊維Ａ、海島型極細短繊維Ｂ及び電解質二酸化マンガン粉末を分散室内で分散させた。
【００８２】
次いで、この分散させた電解質二酸化マンガン粉末、ポリプロピレン極細短繊維Ａ及び海島型極細短繊維Ｂを、ネットからなる支持体上に載置しておいた不織布基材（目付が３０ｇ／ｍ²のポリエステル繊維製スパンボンド不織布）上に集積させ、粉体含有繊維ウエブ−不織布基材複合材を形成した。なお、集積させる際には、支持体の下に設置されたサクションボックスにより空気を吸引（２ｍ³／ｍｉｎ）した。
【００８３】
次いで、この粉体含有繊維ウエブ−不織布基材複合材を、温度１３０℃に設定されたオーブンに供給し、３分間熱処理を実施して、目付９０ｇ／ｍ²、厚さ１．０ｍｍの不織布基材積層粉体固着不織布を製造した。この不織布基材積層粉体固着不織布の粉体固着不織布層は、ポリプロピレン極細短繊維Ａ及び海島型極細短繊維Ｂが電解質二酸化マンガン粉末の周囲を囲むように絡合しているとともに、海島型極細短繊維Ｂを構成する高密度ポリエチレン成分によって、ポリプロピレン極細短繊維Ａと海島型極細短繊維Ｂ、及び海島型短繊維Ｂと電解質二酸化マンガン粉末とが融着した状態にあった。
【００８４】
なお、不織布基材積層粉体固着不織布から不織布基材を剥離し、粉体固着不織布のみについて各種物性を測定したところ、目付は６０ｇ／ｍ²、厚さは０．９ｍｍ、見掛密度は０．０６７ｇ／ｃｍ³で、極細短繊維Ａ，Ｂの質量比率は１５ｍａｓｓ％であった。また、この粉体固着不織布を熱水中に１５分間浸漬して抽出した付着物と、熱メタノール中に１５分間浸漬して抽出した付着物との総付着物質量の、粉体固着不織布の質量に対する百分率（付着物の付着率）は０．０２ｍａｓｓ％未満であった。
【００８５】
この不織布基材積層粉体固着不織布を、エリアカレンダー（温度＝１３０℃）でプレス処理して厚さを０．３ｍｍとした後、コルゲート加工（山高さ＝２ｍｍ，ピッチ＝１．５ｍｍ）し、濃度１０ｐｐｍのオゾンガスを通過させたところ、出口のオゾン濃度は０．１ｐｐｍ以下に低下しており、優れたオゾン分解性能を示した。また振動を与えても不織布基材積層粉体固着不織布からの電解質二酸化マンガン粉末の脱落は観察されなかった。
【００８６】
【実施例３】
共重合ポリエステルからなる海成分中に、結晶性ポリスチレンからなる島成分が６１個存在し、複合紡糸法により得た海島型繊維（繊度＝２．３ｄｔｅｘ；繊維長０．５ｍｍに切断されたもの）を用意した。この海島型繊維を１０ｍａｓｓ％水酸化ナトリウム水溶液中に浸漬して、海成分である共重合ポリエステルを加水分解により抽出除去した後、風乾して、結晶性ポリスチレン極細短繊維（繊維径＝１．１μｍ；繊維長＝０．５ｍｍ；フィブリル化していない；延伸されている；繊維軸方向において実質的に同じ直径を有する；付着物の付着率＝０．０２ｍａｓｓ％未満）が束状となった極細短繊維Ｃの集合体を得た。
【００８７】
また、実施例１と同様にして製造した束状となった極細短繊維Ｂの集合体、及び粉体として球状アルミナ粉末（平均粒径＝２５μｍ）を用意した。
【００８８】
次いで、図１に示す製造装置と同様の装置を用いて、本発明による粉体固着不織布を調製した。すなわち、束状となった極細短繊維Ｃ集合体、束状となった極細短繊維Ｂ集合体、及び球状アルミナ粉末とを、１：１：９８の質量比でミキサーに供給して、これらを解すとともに混合した後、これら混合物を、噴出口における横断面形状が円形（直径＝３．２ｍｍ）で連続的に先細りの先細ノズルに供給するとともに、先細ノズルの手前に設けられた圧縮気体導入口から層流の圧縮空気（圧力＝６ｋｇ／ｃｍ²）を導入し、前記先細ノズルから前記混合物を分散室の空気中に噴出（先細ノズル３０の噴出口における気体通過速度＝１６００ｍ／ｓ）して、結晶性ポリスチレン極細短繊維Ｃ、海島型極細短繊維Ｂ及び球状アルミナを分散室内で分散させた。
【００８９】
次いで、この分散させた結晶性ポリスチレン極細短繊維Ｃ、海島型極細短繊維Ｂ及び球状アルミナを、ネットからなる支持体上に載置しておいた不織布基材（目付が３０ｇ／ｍ²のポリエステル繊維製スパンボンド不織布）上に集積させ、粉体含有繊維ウエブ−不織布基材複合材を形成した。なお、集積させる際には、支持体の下に設置されたサクションボックスにより空気を吸引（２ｍ³／ｍｉｎ）した。
【００９０】
次いで、この粉体含有繊維ウエブ−不織布基材複合材を、温度１３０℃に設定されたオーブンに供給し、３分間熱処理を実施して、目付４１０ｇ／ｍ²、厚さ０．５５ｍｍの不織布基材積層粉体固着不織布を製造した。この不織布基材積層粉体固着不織布の粉体固着不織布層は、結晶性ポリスチレン極細短繊維Ｃ及び海島型極細短繊維Ｂが球状アルミナの周囲を囲むように絡合しているとともに、海島型極細短繊維Ｂを構成する高密度ポリエチレン成分によって、結晶性ポリスチレン極細短繊維Ｃと海島型極細短繊維Ｂ、及び海島型極細短繊維Ｂと球状アルミナとが融着した状態にあった。
【００９１】
なお、不織布基材積層粉体固着不織布から不織布基材を剥離し、粉体固着不織布のみについて各種物性を測定したところ、目付は３８０ｇ／ｍ²、厚さは０．４５ｍｍ、見掛密度は０．８４４ｇ／ｃｍ³で、極細短繊維の質量比率は２ｍａｓｓ％であった。また、この粉体固着不織布を熱水中に１５分間浸漬して抽出した付着物と、熱メタノール中に１５分間浸漬して抽出した付着物との総付着物質量の、粉体固着不織布の質量に対する百分率（付着物の付着率）は０．０２ｍａｓｓ％未満であった。
【００９２】
この粉体固着不織布層を４枚重ね合わせ、温度が１３０℃の熱プレス機でプレス処理（圧力＝５０ｋｇ／ｃｍ²）を施したところ、アルミナ充填率が高く熱伝導性の高い柔軟なシート（目付＝１５２０ｇ／ｍ²；厚さ＝０．７５ｍｍ；見掛密度＝２．０３ｇ／ｃｍ³）が得られた。このシートはアルミナが脱落せず、取り扱い性、強度的に優れるものであった。
【００９３】
【実施例４】
市販のポリエステル極細短繊維（繊維径＝３．２μｍ；繊維長＝３．０ｍｍ；帝人製）を用意し、この繊維表面に付着している繊維油剤をアセトン中で抽出除去した。
【００９４】
また、実施例１と同様にして製造した束状の極細短繊維Ａ集合体と束状の極細短繊維Ｂ集合体を用意した。
更に、粉体として球状アルミナ粉末（平均粒径＝２５μｍ）を用意した。
【００９５】
次いで、図１に示す製造装置と同様の装置を用いて、ポリエステル極細短繊維、束状の極細短繊維Ａ集合体、束状の海島型極細短繊維Ｂ集合体、及び球状アルミナ粉末を、２：２：４：９２の質量比でミキサーに供給して、これらを解すとともに混合した後、これら混合物を、噴出口における横断面形状が円形（直径＝３．２ｍｍ）で連続的に先細りの先細ノズルに供給するとともに、先細ノズルの手前に設けられた圧縮気体導入口から層流の圧縮空気（圧力＝６ｋｇ／ｃｍ²）を導入し、前記先細ノズルから前記混合物を分散室の空気中に噴出（先細ノズルの噴出口における気体通過速度＝１６００ｍ／ｓ）して、ポリエステル極細短繊維、極細短繊維Ａ、海島型極細短繊維Ｂ、及び球状アルミナ粉末を分散させた。
【００９６】
次いで、この分散させたポリエステル極細短繊維、ポリプロピレン極細短繊維Ａ、海島型極細短繊維Ｂ、及び球状アルミナ粉末を、ネットからなる支持体上に載置しておいた不織布基材（目付が３０ｇ／ｍ²のポリエステル繊維製スパンボンド不織布）上に集積させ、粉体含有繊維ウエブ−不織布基材複合材を形成した。なお、集積させる際には、支持体の下に設置されたサクションボックスにより空気を吸引（２ｍ³／ｍｉｎ）した。
【００９７】
次いで、この粉体含有繊維ウエブ−不織布基材複合材を、温度１３０℃に設定されたオーブンに供給し、３分間熱処理を実施して、目付４５０ｇ／ｍ²、厚さ０．６５ｍｍの不織布基材積層粉体固着不織布を製造した。この不織布基材積層粉体固着不織布の粉体固着不織布層は、ポリエステル極細短繊維、ポリプロピレン極細短繊維Ａ及び海島型極細短繊維Ｂが球状アルミナ粉末の周囲を囲むように絡合しているとともに、海島型極細短繊維Ｂを構成する高密度ポリエチレン成分によって、極細短繊維同士、及び海島型極細短繊維Ｂと球状アルミナとが融着した状態にあった。
【００９８】
なお、不織布基材積層粉体固着不織布から不織布基材を剥離し、粉体固着不織布のみについて各種物性を測定したところ、目付は４２０ｇ／ｍ²、厚さは０．５５ｍｍ、見掛密度は０．７６４ｇ／ｃｍ³で、極細短繊維の質量比率は８ｍａｓｓ％であった。また、この粉体固着不織布を熱水中に１５分間浸漬して抽出した付着物と、熱メタノール中に１５分間浸漬して抽出した付着物との総付着物質量の、粉体固着不織布の質量に対する百分率（付着物の付着率）は０．０２ｍａｓｓ％未満であった。
【００９９】
この粉体固着不織布を２枚重ね合わせ、温度１３０℃の熱プレス機でプレス処理（圧力＝５０ｋｇ／ｃｍ²）を施したところ、アルミナ充填率が高く、熱伝導性の高い柔軟なシート（目付＝８４０ｇ／ｍ²；厚さ＝０．４３ｍｍ；見掛密度＝１．９５ｇ／ｃｍ³）が得られた。このシートはアルミナが脱落せず、取り扱い性、強度的に優れるものであった。
【０１００】
【実施例５】
共重合ポリエステルからなる海成分中に、ポリ−４−メチルペンテンからなる島成分が約３９００個存在し、混合紡糸法により得た海島型繊維（繊度＝８．８ｄｔｅｘ；繊維長０．５ｍｍに切断されたもの）を用意した。この海島型繊維を１０ｍａｓｓ％水酸化ナトリウム水溶液中に浸漬して、海成分である共重合ポリエステルを加水分解により抽出除去した後、風乾して、ポリ−４−メチルペンテン極細短繊維（繊維径＝０．４μｍ；繊維長＝０．５ｍｍ；フィブリル化していない；延伸されている；繊維軸方向において直径が変化している；付着物の付着率＝０．０２ｍａｓｓ％未満）が束状となったポリ−４−メチルペンテン極細短繊維Ｄの集合体を得た。
【０１０１】
また、実施例３と同様にして製造した結晶性ポリスチレン極細短繊維Ｃの集合体と、実施例１と同様にして製造した束状となった海島型極細短繊維Ｂの集合体を用意した。
【０１０２】
次いで、図１に示す製造装置と同様の装置を用いて、束状となったポリ−４−メチルペンテン極細短繊維Ｄの集合体、結晶性ポリスチレン極細短繊維Ｃの集合体、及び海島型極細短繊維Ｂの集合体を、４０：２０：４０の質量比でミキサーに供給して、これら繊維を解すとともに混合した後、これら混合物を、噴出口における横断面形状が円形（直径＝３．２ｍｍ）で連続的に先細りの先細ノズルに供給するとともに、先細ノズルの手前に設けられた圧縮気体導入口から層流の圧縮空気（圧力＝６ｋｇ／ｃｍ²）を導入し、前記先細ノズルから前記混合物を分散室の空気中に噴出（先細ノズルの噴出口における気体通過速度＝１６００ｍ／ｓ）して、ポリ−４−メチルペンテン極細短繊維Ｄ、結晶性ポリスチレン極細短繊維Ｃ、及び海島型極細短繊維Ｂを分散させた。
【０１０３】
次いで、この分散させたポリ−４−メチルペンテン極細短繊維Ｄ、結晶性ポリスチレン極細短繊維Ｃ、及び海島型極細短繊維Ｂを、ネットからなる支持体上に載置しておいた不織布基材（目付が３０ｇ／ｍ²のポリエステル繊維製スパンボンド不織布）上に集積させ、極細短繊維ウエブ（脱落防止層；目付＝５ｇ／ｍ²）−不織布基材複合材を形成した。なお、集積させる際には、支持体の下に設置されたサクションボックスにより空気を吸引（２ｍ³／ｍｉｎ）した。
【０１０４】
次いで、前述と同様の束状となったポリ−４−メチルペンテン極細短繊維Ｄの集合体、実施例３と同様にして製造した結晶性ポリスチレン極細短繊維Ｃの集合体、実施例１と同様にして製造した海島型極細短繊維Ｂの集合体、及び粉体としてアナターゼ型二酸化チタン粉末（平均粒径＝０．２μｍ）を用意した。
【０１０５】
次いで、ポリ−４−メチルペンテン極細短繊維Ｄの集合体、結晶性ポリスチレン極細短繊維Ｃの集合体、海島型極細短繊維Ｂの集合体、及びアナターゼ型二酸化チタン粉末を、３：６：６：８５の質量比でミキサーに供給して、これらを解すとともに混合した後、これら混合物を、噴出口における横断面形状が円形（直径＝３．２ｍｍ）で連続的に先細りの先細ノズルに供給するとともに、先細ノズルの手前に設けられた圧縮気体導入口から層流の圧縮空気（圧力＝６ｋｇ／ｃｍ²）を導入し、前記先細ノズルから前記混合物を分散室の空気中に噴出（先細ノズルの噴出口における気体通過速度＝１６００ｍ／ｓ）して、二酸化チタン粉末、ポリ−４−メチルペンテン極細短繊維、結晶性ポリスチレン極細短繊維、及び海島型極細短繊維を分散させた。
【０１０６】
次いで、この分散させたポリ−４−メチルペンテン極細短繊維Ｄ、結晶性ポリスチレン極細短繊維Ｃ、海島型極細短繊維Ｂ、及び二酸化チタン粉末を、前述の極細短繊維ウエブ（脱落防止層；目付＝５ｇ／ｍ²）−不織布基材複合材の極細短繊維ウエブ上で捕集して、粉体含有繊維ウエブ−極細短繊維ウエブ−不織布基材複合材を形成した。なお、集積させる際には、支持体の下に設置されたサクションボックスにより空気を吸引（２ｍ³／ｍｉｎ）した。
【０１０７】
次いで、前述の方法と全く同様にして、ポリ−４−メチルペンテン極細短繊維Ｄの集合体、結晶性ポリスチレン極細短繊維Ｃの集合体、及び海島型極細短繊維Ｂの集合体を分散散布し、前記粉体含有繊維ウエブ−極細短繊維ウエブ−不織布基材複合材の粉体含有繊維ウエブ上で捕集して、極細短繊維ウエブ−粉体含有繊維ウエブ−極細短繊維ウエブ−不織布基材複合材を形成した。
【０１０８】
次いで、この極細短繊維ウエブ−粉体含有繊維ウエブ−極細短繊維ウエブ−不織布基材複合材を、温度１３０℃に設定されたオーブンに供給し、３分間熱処理を実施して、目付２７０ｇ／ｍ²、厚さ０．４２ｍｍの不織布基材積層粉体固着不織布を製造した。この不織布基材積層粉体固着不織布の粉体固着不織布層は、ポリ−４−メチルペンテン極細短繊維Ｄ、結晶性ポリスチレン極細短繊維Ｃ、及び海島型極細短繊維Ｂが二酸化チタン粉末の周囲を囲むように絡合しているとともに、海島型極細短繊維Ｂを構成する高密度ポリエチレン成分によって、極細短繊維同士及び海島型極細短繊維Ｂと二酸化チタンとが融着した状態にあった。また、極細短繊維のみからなる極細短繊維ウエブに由来する繊維層（脱落防止層）によって、二酸化チタン粉末の脱落を防止できる状態にあった。
【０１０９】
なお、不織布基材積層粉体固着不織布から不織布基材を剥離し、三層構造粉体固着不織布のみについて各種物性を測定したところ、目付は２４０ｇ／ｍ²、厚さは０．３２ｍｍ、見掛密度は０．７５０ｇ／ｃｍ³で、粉体固着不織布層における極細短繊維の質量比率は１５ｍａｓｓ％であった。なお、この三層構造粉体固着不織布を熱水中に１５分間浸漬して抽出した付着物と、熱メタノール中に１５分間浸漬して抽出した付着物との総付着物質量の、三層構造粉体固着不織布の質量に対する百分率（付着物の付着率）は０．０２ｍａｓｓ％未満であった。
【０１１０】
この不織布基材積層粉体固着不織布をプリーツ加工したフィルタユニット（山高さ＝２０ｍｍ；ピッチ＝２ｍｍ）を作成し、このフィルタユニットに対して紫外線を照射しながら、トルエンを１００ｐｐｂの濃度で含む空気を速度２０ｃｍ／ｓで通過させたところ、フィルターユニット出口におけるトルエンの除去率は８０％に達した。また、この不織布基材積層粉体固着不織布に対して振動を与えても、二酸化チタン粉末の脱落は観察されなかった。
【０１１１】
【実施例６】
実施例１と同様にして製造した束状海島型極細短繊維Ｂの集合体を用意した。
【０１１２】
次いで、この海島型極細短繊維Ｂの集合体をミキサーに供給して、解した後、海島型極細短繊維Ｂ集合体を、噴出口における横断面形状が円形（直径＝３．２ｍｍ）で連続的に先細りの先細ノズルに供給するとともに、先細ノズルの手前に設けられた圧縮気体導入口から層流の圧縮空気（圧力＝６ｋｇ／ｃｍ²）を導入し、前記先細ノズルから前記混合物を分散室の空気中に噴出（先細ノズルの噴出口における気体通過速度＝１６００ｍ／ｓ）して、海島型極細短繊維Ｂを分散させた。
【０１１３】
次いで、この分散させた海島型極細短繊維Ｂを、ネットからなる支持体上に載置しておいた不織布基材（目付が３０ｇ／ｍ²のポリエステル繊維製スパンボンド不織布）上に集積させ、極細短繊維ウエブ（目付＝５ｇ／ｍ²）−不織布基材複合材を形成した。なお、集積させる際には、支持体の下に設置されたサクションボックスにより空気を吸引（２ｍ³／ｍｉｎ）した。
【０１１４】
次いで、実施例１と同様にして製造した束状となった海島型極細短繊維Ｂの集合体と、粉体として、低密度ポリエチレン粉末（平均粒径＝１２μｍ；住友精化（株）製）を用意した。
【０１１５】
次いで、海島型極細短繊維Ｂ集合体と低密度ポリエチレン粉末とを、５：９５の質量比でミキサーに供給して、解すとともに混合した後、これら混合物を、噴出口における横断面形状が円形（直径＝３．２ｍｍ）で連続的に先細りの先細ノズルに供給するとともに、先細ノズルの手前に設けられた圧縮気体導入口から層流の圧縮空気（圧力＝６ｋｇ／ｃｍ²）を導入し、前記先細ノズルから前記混合物を分散室の空気中に噴出（先細ノズルの噴出口における気体通過速度＝１６００ｍ／ｓ）して、低密度ポリエチレン粉末及び海島型極細短繊維Ｂを分散させた。
【０１１６】
次いで、この分散させた低密度ポリエチレン粉末及び海島型極細短繊維Ｂを、前述の極細短繊維ウエブ（目付＝５ｇ／ｍ²）−不織布基材複合材の極細短繊維ウエブ上に集積させ、粉体含有繊維ウエブ−極細短繊維ウエブ−不織布基材複合材を形成した。なお、集積させる際には、支持体の下に設置されたサクションボックスにより空気を吸引（２ｍ³／ｍｉｎ）した。
【０１１７】
次いで、この粉体含有繊維ウエブ−極細短繊維ウエブ−不織布基材複合材を、温度１０７℃に設定されたオーブンに供給し、５分間熱処理を実施して、目付１１８ｇ／ｍ²、厚さ０．５５ｍｍの不織布基材積層粉体固着不織布を製造した。この不織布基材積層粉体固着不織布は海島型極細短繊維Ｂが低密度ポリエチレン粉末の周囲を囲むように絡合しているとともに、海島型極細短繊維Ｂを構成する高密度ポリエチレン成分と低密度ポリエチレン粉末の一部が溶融し、海島型極細短繊維Ｂ同士及び海島型極細短繊維Ｂと低密度ポリエチレン粉末とが融着した状態にあった。また、海島型極細短繊維Ｂのみからなる極細短繊維ウエブに由来する繊維層（脱落防止層）によって、低密度ポリエチレン樹脂粉末の脱落を防止できる状態にあった。
【０１１８】
なお、不織布基材積層粉体固着不織布から二層構造粉体固着不織布を剥離し、二層構造粉体固着不織布のみについて各種物性を測定したところ、目付は８８ｇ／ｍ²、厚さは０．４５ｍｍ、見掛密度は０．１９６ｇ／ｃｍ³で、粉体固着不織布層における極細短繊維の質量比率は５ｍａｓｓ％であった。また、この二層構造粉体固着不織布は低密度ポリエチレン粉末が脱落しないものであった。更に、この二層構造粉体固着不織布を熱水中に１５分間浸漬して抽出した付着物と、熱メタノール中に１５分間浸漬して抽出した付着物との総付着物質量の、二層構造粉体固着不織布の質量に対する百分率（付着物の付着率）は０．０２ｍａｓｓ％未満であった。
【０１１９】
この二層構造粉体固着不織布を１２５℃に設定されたオーブン中で５分間熱処理したところ、低密度ポリエチレン粉末が溶融してフィルム化し、その低密度ポリエチレン中に海島型極細短繊維Ｂが分散した、柔軟性と強度に優れた繊維強化プラスチック（ＦＲＰ）シート（目付＝８８ｇ／ｍ²；厚さ＝０．１４ｍｍ；見掛密度＝０．６２９ｇ／ｃｍ³）となり、海島型極細短繊維ＢはＦＲＰ中の骨材の役目を果たしていることが判った。
【０１２０】
【発明の効果】
本発明の粉体固着不織布は、小粒径の粉体であっても脱落しにくく、粉体本来の機能を発揮することのできるものである。
前記粉体の平均粒径が５０μｍ以下であると、粉体の機能を最大限に発揮することができる。
前記極細短繊維の前記粉体が固着している層における質量比率が１〜４０ｍａｓｓ％であると、粉体量が多いため、粉体の機能を最大限に発揮することができる。
【０１２１】
前記粉体が固着している層に付着している付着物の付着率が０．５ｍａｓｓ％以下であると、付着物によって粉体の機能が阻害されない。
前記粉体が固着している層の少なくとも片面に、粉体の脱落を防止することのできる脱落防止層を更に備えていると、より確実に粉体の脱落を防止することができる。
本発明の粉体固着不織布の製造方法によれば、繊維径が４μｍ以下で繊維長が３ｍｍ以下の極細短繊維が分散した、湿式法ではない方法により形成された繊維ウエブに、粉体が固着した不織布を容易に製造することができる。
【図面の簡単な説明】
【図１】本発明の粉体固着不織布を製造することのできる製造装置の模式的断面図である。
【符号の説明】
１０・・・混合装置；１１，１２，１３・・・供給管；
２０，２１，２２・・・圧縮気体導入口；
３０，３１，３２・・・ノズル；４０，４１，４２・・・分散室；
４０ａ，４１ａ，４２ａ・・・気体；４５，４６，４７・・・分散室の壁部；
５０，５１・・・支持体；６０，６１・・・気体吸引装置；
７０，７１，７２・・・極細短繊維；
７０ａ，７１ａ，７２ａ・・・粉体；８０・・・繊維ウエブ；
８１・・・単層繊維ウエブ；８２・・・積層繊維ウエブ；
８３・・・熱融着不織布；９０・・・熱融着装置；１００・・・巻き取り装置。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nonwoven fabric to which powder is fixed, that is, a powder-fixed nonwoven fabric, a method for producing the same, and a sheet material including the same.
[0002]
[Prior art]
As the fiber material to which the powder is fixed, for example, JP-A 63-135550 discloses a fiber material carrying a powdery binder. However, since this fiber material is a starting material for manufacturing a glass fiber reinforced plastic molded product, and a fiber having a single fiber diameter of 5 to 20 μm and a length of 4 to 25 mm is used as a glass fiber, The diameter powder is easily detached when subjected to vibration or impact, and cannot be firmly fixed. Japanese Patent Application Laid-Open No. 7-313863 discloses an air for mixing a reinforcing fiber and a powdered resin by using a gas flow when manufacturing a preform in the previous stage of molding a fiber reinforced plastic molded product. A mixing method is described. However, the reinforcing fibers used in this method are obviously thick and long fibers, and have the same drawbacks as described above.
[0003]
In addition, as a method of fixing the powder to the nonwoven fabric, for example, after the powder is sandwiched between the fiber webs, the powder is physically confined between the fibers with a needle punch or the like, and the fixing property is further improved. For this reason, there has been known a method in which a powder is sandwiched by a fiber web containing heat-bonding fibers, and then the powder is bonded to fibers and fibers by heat treatment. However, a powder with a small particle diameter of 50 μm or less is easily detached when subjected to vibration or impact, and only a relatively large powder having an average particle diameter exceeding 50 μm can be fixed. There was a drawback.
On the other hand, as a method for improving the retention of powder having an average particle size of 50 μm or less by giving a finer structure to the fiber web, a method of mixing the powder with the fiber by a wet method It has been known. However, since surfactants and pastes are added to the slurry used in this wet method, these surfactants and pastes cover the surface of the powder, and the original function of the powder is lost. There was a drawback that it was easy.
[0004]
[Problems to be solved by the invention]
In order to solve the problems as described above, the present inventor has a powder-bonded nonwoven fabric that can be easily removed even if it is a powder having a small particle diameter and that can exhibit the original function of the powder, and its production. As a result of diligent research aiming at the development of the method, it is necessary to use a fiber web formed by a method other than the wet method in order to prevent the powder from losing its original function. In order to prevent the nonwoven fabric from falling off, it is necessary to disperse ultrafine short fibers of a certain thickness or less and a certain length or less, and make the ultrafine short fibers exist around the powder (preferably entangled in a spider web shape). It has been found that the above-mentioned problems can be solved by reducing the gap between the ultrafine short fibers.
The present invention is based on these findings.
[0005]
[Means for Solving the Problems]
Accordingly, the present invention is a powder-fixed nonwoven fabric comprising a powder and ultrafine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, the powder-fixed nonwoven fabric being dispersed throughout the powder-fixed nonwoven fabric. The fiber is not present in a bundle state, the ultra-short fiber is made of an island component obtained by removing the sea component of the sea-island fiber, An aggregate of ultrafine short fibers or a group of those aggregates are ejected from a nozzle into a gas together with powder by the action of a compressed gas. The present invention relates to the powder-fixed nonwoven fabric formed from the powder-containing fiber web formed by the method of forming the fiber web.
[0006]
In the powder-fixed nonwoven fabric, when the average particle size of the powder is 50 μm or less, the function of the powder can be exhibited to the maximum. Moreover, since the amount of powder is large when the mass ratio of the ultrafine short fibers to the total mass of the powder-fixed nonwoven fabric is 1 to 40 mass%, the function of the powder can be maximized. Furthermore, if the adhesion rate of the deposit is 0.5 mass% or less, the function of the powder is not inhibited by the deposit.
[0007]
The present inventor, together with powder, an aggregate of ultrafine short fibers or a group of those aggregates and / or a separable fiber that can be mechanically divided to generate ultrafine short fibers, or an aggregate thereof. When ejected into the gas from the nozzle by the action of compressed gas, the above-mentioned aggregate of ultra-short fibers or a group of these and / or split fibers that can be mechanically divided to generate ultra-short fibers, Alternatively, they have found that aggregates and the like are opened and dispersed, and the dispersion of the powder progresses, and the individual fine powders are intertwined in a spider web shape.
[0008]
Therefore, the present invention provides an assembly of ultra-fine short fibers or a group of those having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, and / or a mechanically divided fiber diameter of 4 μm or less and a fiber length. A splitting fiber capable of generating ultra-short fibers of 3 mm or less, or an assembly thereof is ejected into a gas from a nozzle by the action of a compressed gas together with powder, and the ultra-fine fiber assembly or an assembly thereof Dividing the group into ultrafine short fibers and / or dividing the splittable fibers or their aggregates into ultrafine short fibers and dispersing the powder;
Included in the powder-containing fiber web when the dispersed ultrafine short fibers and powder are accumulated to form a powder-containing fiber web, and when forming a nonwoven fabric from the obtained powder-containing fiber web Fixing the powder to be
It is related also with the manufacturing method of the powder fixed nonwoven fabric characterized by including this.
[0009]
Furthermore, the present invention provides a powder-fixed nonwoven fabric comprising a powder and ultrafine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, the powder-fixed nonwoven fabric being dispersed throughout the powder-fixed nonwoven fabric. The fiber is not present in a bundle state, the ultra-short fiber is made of an island component obtained by removing the sea component of the sea-island fiber, An aggregate of ultrafine short fibers or a group of those aggregates are ejected from a nozzle into a gas together with powder by the action of a compressed gas. It also relates to a sheet material, characterized in that it comprises at least one layer of said powder-fixed nonwoven fabric formed from a powder-containing fiber web formed by a method of forming a fiber web.
The sheet material may further include a powder-free layer (powder-free layer), for example, a powder fall-off prevention layer, on at least one side of the powder-fixed nonwoven fabric layer. It is possible to prevent the powder from falling off more reliably.
[0010]
Furthermore, the present invention provides an assembly of ultrafine short fibers or a group of those having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, and / or a mechanically divided fiber diameter of 4 μm or less. A splitting fiber capable of generating ultrafine fibers having a diameter of 3 mm or less, or an aggregate thereof is ejected into a gas from a nozzle by the action of a compressed gas together with powder, and the ultrafine fiber aggregate or an aggregate thereof Dividing the body group into ultrafine short fibers and / or dividing the splittable fibers or their aggregates into ultrafine short fibers and dispersing the powder;
Included in the powder-containing fiber web when the dispersed ultrafine short fibers and powder are accumulated to form a powder-containing fiber web, and when forming a nonwoven fabric from the obtained powder-containing fiber web Fixing the powders that are present, and simultaneously bonding the powder-free layers together with them,
It is related also with the manufacturing method of the sheet material containing a powder fixed nonwoven fabric layer characterized by including these.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The powder-fixed nonwoven fabric of the present invention contains ultrafine short fibers having a fiber diameter of 4 μm or less so as to be excellent in powder retention. The smaller the fiber diameter of the ultrafine short fiber, the better the powder retention, and the smaller the particle diameter of the powder can be held. Therefore, the fiber diameter of the ultrafine short fiber is preferably 3 μm or less, preferably 2 μm or less. More preferably. The lower limit of the fiber diameter of the ultrafine short fiber is not particularly limited, but about 0.01 μm is appropriate.
“Fiber diameter” in this specification refers to the diameter when the cross-sectional shape of the fiber is circular, and when the cross-sectional shape of the fiber is non-circular, the diameter of the circle having the same cross-sectional area and area is used. Say.
[0012]
The ultrafine short fibers constituting the powder-fixed nonwoven fabric of the present invention have a fiber length of 3 mm or less so as to be excellent in uniform dispersibility. That is, when the fiber length is more than 3 mm, the dispersibility is lowered because the degree of freedom of the ultrafine fiber is low. A more preferable fiber length is 2 mm or less. In addition, the lower limit of the fiber length of the ultrafine short fiber is not particularly limited, but about 0.1 mm is appropriate. Moreover, it is preferable that it is an ultra fine short fiber cut | disconnected by the fiber length of 3 mm or less so that fiber length may be uniform.
The “fiber length” in this specification refers to a length obtained by JIS L 1015 (chemical fiber staple test method) B method (corrected staple diagram method).
[0013]
The ultrafine short fiber used in the present invention can be composed of any component (for example, an organic component or an inorganic component). For example, polyamide resin, polyvinyl alcohol resin, polyvinylidene chloride resin, polyvinyl chloride resin Polyester resins, polyacrylonitrile resins, polyolefin resins (eg, polyethylene resins, polypropylene resins, etc.), polystyrene resins (eg, crystalline polystyrene, amorphous polystyrene, etc.), wholly aromatic polyamide resins, It can be comprised from organic components, such as a polyurethane-type resin, inorganic components, such as glass, carbon, potassium titanate, silicon carbide, silicon nitride, zinc oxide, aluminum borate, and wollastonite.
[0014]
In general, when the ultrafine fiber is made of an organic component, the rigidity is lower and softer than when it is made of an inorganic component. Therefore, the ultrafine fiber is easily entangled and difficult to disperse uniformly. In spite of the difficulty in obtaining the advantages of containing the non-woven fabric, the powder-fixed nonwoven fabric of the present invention has an advantage that the ultrafine short fibers are made of an organic component because the ultrafine short fibers are uniformly dispersed. (For example, bulkiness, texture, or elasticity) can be improved.
[0015]
In order to maintain the nonwoven fabric form of the powder-fixed nonwoven fabric according to the present invention, it is preferable that the fibers are bonded to each other. However, if the ultrashort fibers can be fused, the nonwoven fabric form is formed by fusing the ultrafine short fibers. This is preferable because it can be maintained, and the ultrafine short fibers and powder are less likely to fall off. It is preferable that at least a part of components constituting the ultrafine short fiber surface of the ultrafine short fiber that can be fused is made of a thermoplastic resin. For example, the component constituting the surface of the ultrafine fiber is a crystal such as polyolefin resin (eg, polyethylene resin, polypropylene resin, etc.), polyvinylidene chloride resin, polyester resin, polyamide resin, crystalline polystyrene resin, etc. Or a non-crystalline thermoplastic resin such as a polyvinyl chloride resin, an amorphous polystyrene resin, a polyacrylonitrile resin, a polyvinyl alcohol resin, or a polyvinyl acetate resin. Among these, a polyethylene resin having a relatively low melting point and a polyvinyl acetate resin having a relatively low melting point are preferable. It is also possible to use inorganic fibers such as glass fibers or metal fibers such as copper fibers.
[0016]
It is preferable that the meltable ultrafine short fiber is composed of two or more types of components because even if one type of component is fused, the fiber form can be maintained by at least one type of component. . The cross-sectional shape of the ultrafine short fiber that can be fused when composed of two or more components is, for example, a core-sheath type, an eccentric type, a sea-island type, a side-by-side type, a multi-bimetal type, or an orange type. be able to.
[0017]
The ultrafine short fibers used in the present invention have substantially the same diameter (that is, have substantially the same diameter) in the fiber axis direction so that the texture of the powder-fixed nonwoven fabric is excellent. Are preferred).
In this way, for each ultrafine short fiber, the ultrafine short fiber whose diameter is substantially the same in the fiber axis direction and has not changed is, for example, a composite by extruding the island component by regulating the die into the sea component at the spinneret portion. It can be obtained by removing the sea component of the sea-island fiber obtained by the composite spinning method. In general, when the sea component of the sea-island fiber is removed to form an ultrafine short fiber, each ultrafine fiber derived from the island component exists as a bundled aggregate, and the ultrashort fiber is mutually connected. Since they are close to each other, they are easily entangled and it is difficult to uniformly disperse them, so it is difficult to obtain the advantages of containing ultrafine short fibers. Even if an ultra-short fiber aggregate is used, the ultra-short fibers are not present in a bundle state and can be uniformly dispersed. Therefore, the advantage of containing the ultra-short fibers can be obtained. In addition, bundle-like ultrafine fiber aggregates formed by removing sea components from sea-island fibers are generally easy to aggregate and difficult to disperse, but in the present invention, they can be dispersed. Advantages of containing ultrafine short fibers can be obtained.
[0018]
Further, the ultrafine short fibers used in the present invention can be in an unstretched state, but are preferably in a stretched state so as to be excellent in strength.
[0019]
In the powder-fixed nonwoven fabric of the present invention, since the powder is fixed to the fiber web in which the ultra-short fibers are dispersed as described above, the powder can be held by the ultra-short fibers and can be prevented from falling off. . In addition, since this fiber web is formed by a method other than the wet method, the powder is not coated with a surfactant or a paste like the fiber web formed by the wet method. The function of can be demonstrated. A method other than the wet method, that is, a method other than the wet method, is not particularly limited as long as it is different from the method of dispersing ultrashort fibers and powder using a slurry containing a surfactant and / or a paste. Although not intended, there can be mentioned, for example, a method of forming a fiber web using a gas as a dispersion medium. In particular, a method is preferred in which the ultrafine short fibers dispersed in the gas are deposited by dropping and then fixed by an appropriate fixing method (for example, heat fusion method).
[0020]
The powder used in the present invention can be an organic powder, an inorganic powder, a metal powder, or a composite powder of an organic substance and an inorganic substance (for example, an organic resin-coated inorganic powder). It can select suitably by the use to which a body fixing nonwoven fabric is applied. For example, when the powder-fixed non-woven fabric is used for decomposing ozone, activated carbon or the like can be used as the powder, and when the powder-fixed non-woven fabric is used for ion exchange, an ion exchange resin is used. Powders can be used, and when powder-fixed nonwoven fabrics are used for catalyst applications, catalyst powders such as manganese dioxide, platinum, or titanium oxide can be used. When used for deodorization applications, deodorant powder, deodorant powder, etc. can be used, and powder-fixed nonwoven fabric such as fiber reinforced plastic (FRP) or sheet-shaped prepreg (SMC) is used. When used for applications, heat-adhesive resin powder can be used, and powder-fixed non-woven fabric is used for fiber-reinforced plastics such as ships and bathtubs ( When used in applications such as overlays) may be used, such as thermosetting resin powder, or in the case of using the powder affixed nonwoven fabric in fireproof board, or the like can be used inorganic powder.
[0021]
In addition, as a powder, for example, heat-fusible resin powder (for example, polypropylene, polyethylene, etc.), thermosetting resin powder (for example, thermosetting polyethylene terephthalate, phenol resin), inorganic powder (for example, glass) ) And metal powder (for example, zinc, aluminum, tin, etc.) are preferable because the powder can be securely fixed to the powder-fixed nonwoven fabric by the adhesive action of these powders.
[0022]
In addition, when a heat-fusible resin is included as a part of the surface of the powder itself, the heat-fusible resin can surely fix the powder to the powder-fixed nonwoven fabric. one of.
[0023]
In the powder-fixed non-woven fabric of the present invention, since the ultrafine short fibers as described above are used, even a powder having an average particle diameter of 50 μm or less, which has been easy to drop in the past, can be held without dropping. Can do. Since this powder is mainly held by ultrafine short fibers, the powder that can be held varies depending on the fiber diameter of the ultrafine short fibers. That is, in the powder-fixed nonwoven fabric of the present invention, it is possible to select ultrafine short fibers having an appropriate fiber diameter according to the average particle diameter of the powder to be held. For example, Table 1 shows the relationship between the fiber diameter of the ultra-fine short fibers and the optimum average particle diameter of the powder.
[0024]
[Table 1]

[0025]
Even if the average particle diameter of the powder exceeds 50 μm, the powder can be held by the fiber web as described above.
The “average particle diameter” of the powder in the present invention refers to a value obtained by a Coulter counter method.
[0026]
Since such powder is fixed by the fiber web as described above, the powder does not fall off from the powder-fixed nonwoven fabric. This “fixed state” means a state in which the powder is fixed. For example, the state in which the powder is fixed by surrounding the powder mainly with the ultrafine short fiber, the ultrafine short fiber, and / Or refers to a state in which the powder is fixed by fusion of thick fibers, which will be described later, or a state in which the powder is fixed due to these multiple factors.
[0027]
In the powder-fixed nonwoven fabric according to the present invention, the mass ratio of the ultrafine short fibers as described above varies depending on the average particle diameter, specific gravity of the powder, or the fiber diameter of the ultrafine short fibers. Even a powder having a small particle diameter of about 50 μm or less can be held so as not to fall off, and can be a powder-fixed non-woven fabric in which almost no powder falls off even at 20 mass% or less, and is practical even at 10 mass% or less. It can be a powder-fixed non-woven fabric that has no problem and practically has no problem in strength during handling. On the other hand, if the mass ratio of the ultrafine short fibers is 1 mass% or more, the powder is difficult to fall off and has practical handling strength.
[0028]
In the powder-fixed nonwoven fabric of the present invention, at least the above-mentioned ultrafine short fibers are dispersed, so that the effect of including the ultrafine short fibers can be exhibited. The content of the ultrafine short fibers in the powder-fixed nonwoven fabric constituting fiber is preferably 20 mass% or more, and preferably 50 mass% or more so that the effect of including the ultrafine short fibers can be exhibited. Is more preferable, and 100 mass% is most preferable.
[0029]
In the powder-fixed nonwoven fabric of the present invention, as fibers other than the above-mentioned ultrafine short fibers, (1) fibers having a fiber diameter exceeding 4 μm but having a fiber length of 3 mm or less (hereinafter referred to as thick fibers), (2) fibers A fiber having a diameter of 4 μm or less but a fiber length exceeding 3 mm (hereinafter referred to as a long fiber), or (3) a fiber having a fiber diameter exceeding 4 μm and a fiber length exceeding 3 mm (hereinafter referred to as a thick fiber). ) Can be used. Among these, long fibers and thick fibers having a fiber length exceeding 3 mm have poor dispersibility and may impair the dispersibility of ultrafine short fibers. Therefore, it is preferable to use thick fibers having a fiber length of 3 mm or less.
[0030]
When using the above thick fibers, the upper limit of the fiber diameter is not particularly limited, but if the difference in fiber diameter from the ultrafine short fibers is too large, the texture of the powder-fixed nonwoven fabric may be impaired. The upper limit of the fiber diameter of the fiber is preferably about 50 μm.
In addition, it is preferable that the said thick fiber is 2 mm or less so that it may be excellent in a dispersibility. The lower limit is not particularly limited, but about 0.1 mm is appropriate. The thick fibers are preferably cut to a length of 3 mm or less so as to have a uniform length.
[0031]
This thick fiber can also be comprised from the component similar to an ultrafine short fiber. That is, for example, polyamide resin, polyvinyl alcohol resin, polyvinylidene chloride resin, polyvinyl chloride resin, polyester resin, polyacrylonitrile resin, polyolefin resin (for example, polyethylene resin, polypropylene resin, etc.), Organic components such as polystyrene resins (crystalline polystyrene, amorphous polystyrene, etc.), wholly aromatic polyamide resins, polyurethane resins, glass, carbon, potassium titanate, silicon carbide, silicon nitride, zinc oxide, aluminum borate , And can be composed of inorganic components such as wollastonite.
[0032]
In addition, when the said thick fiber can be melt | fused, the nonwoven fabric form of the powder fixed nonwoven fabric by this invention can be maintained by melt | fusion of a thick fiber. In this thick fiber that can be fused, at least a part of the components constituting the surface of the thick fiber can be composed of a thermoplastic resin. For example, the component constituting the thick fiber surface is crystalline such as polyolefin resin (for example, polyethylene resin, polypropylene resin, etc.), polyvinylidene chloride resin, polyester resin, polyamide resin, crystalline polystyrene resin, etc. Or an amorphous thermoplastic resin such as polyvinyl chloride resin, amorphous polystyrene resin, polyacrylonitrile resin, or polyvinyl alcohol resin. Among these, a polyethylene resin having a relatively low melting point and a polyvinyl acetate resin having a relatively low melting point are preferable. In addition, it can also be inorganic fibers, such as glass fiber, and metal fibers, such as copper fiber.
[0033]
When this fusible thick fiber is composed of two or more components having different melting points, even if one component is fused, the fiber form can be maintained by at least one other component. Therefore, it is preferable. When the fusion-bondable thick fiber is composed of two or more types of components, the cross-sectional shape of the fusion-bondable thick fiber is, for example, a core-sheath type, an eccentric type, a sea-island type, a side-by-side type, or a multiple bimetal type Or orange type.
The thick fibers may be in an unstretched state, but are preferably in a stretched state so as to be excellent in strength.
[0034]
The adhesion rate of the adhered matter (surfactant, glue, etc.) adhering to the powder-fixed nonwoven fabric of the present invention is 0.5 mass% or less so that the powder does not impair the function of the adhered matter. Preferably there is. The smaller the adhesion rate of this deposit, the more the function of the powder is not impaired. Therefore, the adhesion rate is preferably 0.3 mass% or less, more preferably 0.1 mass% or less, and even more preferably 0.08 mass%. Hereinafter, it is still more preferably 0.06 mass% or less, still more preferably 0.04 mass% or less, and still more preferably 0.02 mass% or less. Such a low adhesion rate of the deposit is a level that cannot be obtained by a conventional wet method. In addition, even if a water flow or the like is applied to a wet fiber web (including powder) to which a surfactant or a paste is adhered, it is difficult to reduce the adhesion rate of the adhered material to 0.5 mass% or less. is there.
[0035]
In the powder-fixed nonwoven fabric of the present invention, if the adhesion rate of the adhered material is low, the risk of detaching the adhered material during use of the powder-bonded nonwoven fabric is extremely low, thereby bringing various favorable effects. For example, in general, when a normal non-woven fabric is used as a filter, even if dust contained in the fluid before filtration can be physically removed by the filter, the filter (non-woven fabric) itself does not remove contaminants. When it occurs, the role as a filter is halved. On the other hand, the powder-fixed nonwoven fabric of the present invention or the sheet material according to the present invention containing at least one layer of the powder-fixed nonwoven fabric has a small amount of deposits and has a very low possibility of deposits being detached. Therefore, it can be suitably used as a filter.
[0036]
The adhesion rate of this deposit refers to the percentage of the mass of the deposit relative to the mass of the powder-fixed nonwoven fabric. That is, the following formula (1):
A = (ms / mf) × 100 (1)
[Here, A means the adhesion rate (%) of the deposit, ms means the mass (g) of the deposit, and mf means the mass (g) of the powder-fixed nonwoven fabric]
The value obtained by
Further, in the “adhesive” in the present specification, an extract obtained by immersing a powder-fixed nonwoven fabric in hot water (for example, water at 80 to 100 ° C.) for 15 minutes (hereinafter referred to as hot water extract). ) And an extract obtained by immersing the powder-fixed nonwoven fabric in a hot methanol solution for 15 minutes (hereinafter referred to as a hot methanol extract). Examples of hot water extracts include pastes (for example, acrylamide, sodium polyacrylate, sodium alginate, polyethylene oxide, methyl cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, and polyvinyl alcohol), and hot methanol extracts include surfactants ( There are compounds having both a hydrophilic group and a lipophilic group, such as nonionic surfactants.
[0037]
In the powder-fixed nonwoven fabric of the present invention, it is preferable that the fibers (ultrafine short fibers, thick fibers, etc.) and / or powder constituting the nonwoven fabric are fused. This is because the powder is more difficult to fall off due to the fusion.
[0038]
The powder-fixed non-woven fabric of the present invention does not have to be a single layer, and may include two or more layers in which the powder is fixed and the ultrashort fibers are dispersed. When the powder is fixed and the layer having two or more layers in which the ultrafine short fibers are dispersed, various characteristics can be imparted. For example, a powder-fixed non-woven fabric having a powder-fixed non-woven fabric layer to which ion-exchange resin powder is fixed and a powder-fixed non-woven fabric layer to which a deodorant powder is fixed has both ion exchange performance and deodorization performance. is there.
[0039]
The powder-fixed nonwoven fabric of the present invention is sufficiently practical that the powder does not easily fall off even if it is composed of only the powder-fixed nonwoven layer to which the powder is fixed as described above. However, if it should not fall off, the powder-fixed non-woven fabric layer to which the powder is fixed as described above should not have a powder-free layer, for example, a powder on the surface side (at least one side) where the powder should not fall off. It is preferable to further include a drop-off preventing layer that can prevent the body from falling off.
[0040]
The drop-off preventing layer is not particularly limited as long as it has a function of preventing the powder from dropping off, but the fiber diameter is the same as or smaller than the ultrafine short fiber constituting the powder-fixed nonwoven fabric layer. It is preferable that the non-woven fabric is derived from a fiber web containing thin ultra-short fibers (that is, fiber diameter of 4 μm or less). However, the fiber diameter also varies depending on the average particle diameter of the fixed powder. This nonwoven fabric maintains the nonwoven fabric form by, for example, fusion of ultrafine short fibers. Such a nonwoven fabric can be produced, for example, by a method in which powder is not supplied when forming a powder-fixed nonwoven fabric layer as described below, and an ultrafine short fiber is formed by a normal wet method. After that, it is possible to make use of the fusing property of ultrafine short fibers, entanglement with a fluid flow such as a water flow, or a combination thereof.
[0041]
Depending on the average particle size of the powder, a non-woven fabric obtained by a melt blow method or a fiber web containing fibers that can be mechanically divided is formed by a dry method or a wet method, and then entangled by a fluid flow such as a water flow. A non-woven fabric or the like can be used as a drop-off preventing layer.
[0042]
The basis weight of the drop-off prevention layer varies depending on the fiber, structure, average particle diameter of the powder, etc. constituting the drop-off prevention layer, and is not particularly limited, but the basis weight is 1 g / m. ² If it is above, it can become a drop-off prevention layer having no practical problem at all.
[0043]
Since the powder-fixed nonwoven fabric of the present invention is excellent in various properties due to the inclusion of ultrafine short fibers and powder, at least one of the powder-fixed nonwoven fabric layer or the powder-fixed nonwoven fabric layer of the present invention. In the form of a sheet material including a layer, for example, an ozone decomposition sheet for an electrophotographic apparatus, a toilet deodorizer, or an ozone generator; an ion exchange sheet such as an ion exchange water purifier; an automobile or a chemical Catalyst sheets for reactors, etc .; deodorizing or deodorizing sheets for daily use, sanitary products, filters, shoes, etc .; fiber reinforced plastic (FRP) or sheet-like prepreg (SMC); or fireproof boards It can be used for various purposes.
[0044]
The powder-fixed nonwoven fabric of the present invention can be produced, for example, by the following method.
First, an aggregate (especially a bundle of aggregates) or a group of aggregates (particularly, a plurality of bundles) of the above powder and a fiber diameter of 4 μm or less and a fiber length of 3 mm or less. Aggregate group including aggregates in a bundle) and / or separable fibers capable of generating ultra-short fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less by mechanical division, or an assembly thereof (In particular, a bundle-like aggregate) is prepared. In addition, the adhesion rate of deposits (surfactant, glue, etc.) as the above-mentioned ultrafine fiber aggregates or a group of these aggregates and / or split fibers capable of generating ultrafine short fibers or the aggregates thereof 0.5 mass% or less (preferably 0.3 mass% or less, more preferably 0.1 mass% or less, even more preferably 0.08 mass% or less, still more preferably 0.06 mass% or less, and even more preferably 0.04 mass% or less. % Or less, and even more preferably 0.02 mass% or less), and / or the group of aggregates thereof, and / or the split fibers that can generate ultrafine short fibers or the aggregates thereof are used. This makes it easy to produce a powder-fixed nonwoven fabric.
[0045]
For example, the ultrafine short fiber aggregate or the group of aggregates with a low adhesion rate of the deposits, or the splittable fibers capable of generating ultrafine short fibers or the aggregate thereof have, for example, a fiber diameter of 4 μm or less and a fiber length of 3 mm or less. After preparing a commercially available ultrafine short fiber aggregate or a group of them, or a splittable fiber capable of generating ultrafine short fibers or an aggregate thereof, the adhesion rate of deposits is 0.5 mass% with a solvent such as acetone. It can be obtained by washing until: Alternatively, an ultrafine short fiber aggregate or a group of those aggregates with a low adhesion rate of deposits is extracted and removed from, for example, sea-island fibers or sea-island fiber groups produced by a composite spinning method or a mixed spinning method. Can be obtained. Further, if the sea component is extracted and removed from the sea-island fiber and then washed with a solvent such as acetone, the amount of deposits can be further reduced. In addition, when the deposit is removed, static electricity is likely to be generated on the surface of the ultrafine short fibers, and the ultrafine short fibers are repelled from each other and easily dispersed.
[0046]
In addition, when the ultrafine short fiber aggregates or the ultrafine short fibers in the aggregate group are in an entangled state, it becomes difficult to uniformly disperse the ultrafine short fibers even by the action of a compressed gas as described later. Since there is a tendency or the compressed gas needs to be applied many times, it is preferable that the ultra-short fiber aggregate or the ultra-short fiber in the aggregate group is not in an entangled state. For example, ultrafine fiber aggregates beaten with mechanically splittable fibers using a beater or the like, pulp beaten with a beater or the like, or ultrafine fiber aggregates obtained by flash spinning, etc. It is preferable not to use because the fibers are in an entangled state. In addition, it is possible to generate ultrafine short fibers capable of generating ultrafine short fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less by mechanically dividing by the action of compressed gas, or an aggregate thereof (for example, all Aromatic polyamide short fibers or aggregates thereof, cellulose short fibers obtained by a solvent extraction method or aggregates thereof, and the like can be used. Moreover, also when using the said thick fiber or those aggregates, it is preferable to carry out acetone washing | cleaning etc. previously and to make it the state with few adhesion rates of a deposit | attachment.
[0047]
Next, the above-mentioned ultrafine short fiber aggregate or group of aggregates as described above, and / or a splittable fiber capable of generating ultrafine short fibers or an aggregate thereof (in some cases, a thick fiber or an aggregate thereof) In addition to the powder as described above, the compressed gas is supplied to the nozzle and jetted into the gas from the nozzle, and the ultrafine fiber aggregate or a group of these aggregates is changed into the ultrafine short fiber. Dividing and dispersing the ultrafine short fibers and / or generating ultrafine short fibers from the splittable fibers capable of generating ultrafine short fibers or aggregates thereof, and dispersing the ultrashort fibers. In addition, when it contains a thick fiber or those aggregates, a thick fiber is disperse | distributed, or a thick fiber is divided | segmented and disperse | distributed from an aggregate. Along with these dispersions, the powder as described above is also dispersed simultaneously.
[0048]
The gas flow supplied to the nozzle is preferably substantially laminar. In the case of laminar flow, entanglement between ultrafine short fibers is difficult to occur, so that the ultrafine short fibers are easily dispersed. In general, when the fiber diameter of the fiber passing through the nozzle is as thin as 4 μm or less (particularly 2 μm or less) and the rigidity is low (soft), a bundle of ultrafine short fiber aggregates or a group of those aggregates (particularly, In the case of a bundle of ultrafine short fiber aggregates or a group of aggregates derived from island components of sea-island type fibers, or when the ultrafine short fibers are composed of organic components and have low rigidity (soft), they are easily entangled. However, even in such a case, the entanglement can be suppressed by making the flow of gas supplied to the nozzle substantially laminar. In addition, by using a venturi tube as a nozzle, the gas flow passing through the nozzle can be made substantially laminar.
[0049]
The nozzle may have a constant cross-sectional area from the supply side to the ejection side (in the flow direction) of the powder and the ultrashort fiber aggregate, but is continuous in the flow direction. The cross-sectional area may be reduced or increased continuously or discontinuously, or the cross-sectional area may be changed to decrease after the cross-sectional area increases continuously or discontinuously in the flow direction. Or it can change so that it may become large, after a cross-sectional area becomes small continuously or discontinuously in a flow direction. Further, the powder ejected from the nozzle outlet, and bundle-like ultrashort fiber aggregates (or a group thereof) and / or fibers capable of generating ultrafine short fibers (or an aggregate thereof), Collision with a collision member (for example, baffle plate) provided in front of the nozzle injection port, the powder, and bundles of ultrafine fiber aggregates or groups of these aggregates and / or possible splitting of ultrafine fibers The generation efficiency of the ultrafine short fibers from the fibers (or their aggregates) and the dispersion efficiency of the generated ultrafine short fibers can be improved. In particular, when the flow of gas supplied to the nozzle is substantially laminar, since the action of dividing and dispersing the powder and ultrafine short fibers is poor, a collision member (for example, a baffle plate) is provided for dispersion. It is preferable to promote.
[0050]
Arbitrary gas can be utilized as compressed gas and it is suitable on manufacture of a powder fixed nonwoven fabric to use air. In addition, the compressed gas can disperse the powder, and can sufficiently disperse the ultrafine short fiber aggregate or the group of aggregates, and / or the splittable fiber capable of generating the ultrafine short fiber or the aggregate thereof. It is preferable that the gas passage speed at the nozzle outlet of the nozzle is 100 m / sec or more so that can be sufficiently dispersed by being divided into ultrafine short fibers. This “gas passage speed” is the flow rate of the gas ejected from the nozzle at 1 atm (m ^Three / Sec) is the cross-sectional area (m ² The value divided by). In addition, the pressure of the compressed gas disperses the powder, sufficiently disperses the ultrafine short fiber aggregate or the group of aggregates, and / or the fine fibers capable of generating the ultrafine short fiber or the aggregate of the fine fibers. 2kg / cm so that it can be divided into short fibers and fully dispersed ² The above is preferable.
[0051]
Further, the fine powders ejected from the nozzles are dispersed, and the ultrafine short fiber aggregates or the group of the aggregates are divided into ultrafine short fibers, sufficiently dispersed, and / or splittable fibers capable of generating ultrafine short fibers. Alternatively, the gas as a dispersion medium that divides the aggregate into ultrafine short fibers and sufficiently disperses them is not particularly limited, but air is suitable for the production of the powder-fixed nonwoven fabric.
[0052]
In addition, if the adhesion rate of the extra fine fiber aggregates or the group of aggregates and / or the split fine fibers capable of generating ultra fine short fibers or the aggregates thereof is low, static electricity is generated due to friction between the nozzle and them. It is easy to occur, and the effect is that the ultra-short fibers repel each other and can be accumulated in a more dispersed state.
[0053]
Subsequently, the dispersed powder and the dispersed ultrafine short fibers (including dispersed thick fibers in some cases) are accumulated to form a powder-containing fiber web. The accumulation of the powder and the ultrafine short fibers can be performed using a support such as a porous roll or a net, for example. It should be noted that the powder and the ultrafine short fibers can be naturally dropped and accumulated, or can be accumulated by sucking gas from below the support. In the latter case, if the suction force is increased, the powder-containing fiber web can be in a state where the powder and the ultra-short fiber are in close contact, and if the suction force is decreased, the powder-containing fiber web is relatively bulky. be able to.
[0054]
In the present invention, since the mass ratio of the ultrafine short fibers to the total mass of the powder-containing fiber web can be 1 to 40 mass%, the amount of the powder is large and the function of the powder is sufficient. It can be demonstrated. Such adjustment of the amount of the ultrafine fiber and the powder is performed by supplying the powder and the ultrafine fiber aggregate or the aggregate group thereof and / or the ultrafine short fiber generating splitting fiber or the aggregate to the nozzle. This can be done by adjusting the amount.
[0055]
Next, the powder contained in the powder-containing fiber web can be fixed to produce the powder-fixed nonwoven fabric of the present invention. This fixing method is not particularly limited, and examples thereof include a method of fusing fibers (ultrafine short fibers and / or thick fibers) and / or powder.
[0056]
The above is the basic production method of the powder-fixed nonwoven fabric of the present invention, but the powder and the ultrafine short fiber aggregate or a group of these aggregates so that the powder and the ultrafine short fiber are easily dispersed uniformly. And / or before the aggregate of the splittable fibers capable of generating ultrafine short fibers is ejected from the nozzle into the gas by the action of the compressed gas, the aggregate of ultrafine short fibers (or aggregates) having a smaller number is used by using a mixer or the like. It is preferable to subdivide, disperse, and mix into a group of body groups) and / or an assembly of split fibers that can generate fewer ultrafine short fibers.
[0057]
In addition, after the powder-containing fiber web is formed and before the powder is fixed, the powder-containing fiber web is supplied again to the same or different nozzle, and the powder and the ultra-short fiber are ejected from the nozzle into the gas. And redispersing to form a powder-containing fiber web can be repeated.
[0058]
In addition, in order to obtain a powder-fixed non-woven fabric containing two or more types of ultrafine short fibers and / or thick fibers that differ in terms of fiber diameter, the ultrafine short fiber aggregates or a group of those aggregates, or the ultrafine fibers are obtained. Short fiber-generating splittable fibers or aggregates thereof and / or thick fiber aggregates can be used in combination.
Also, fiber aggregates or groups of aggregates containing ultrafine short fibers that differ in terms of fiber diameter, splittable fibers that can generate ultrafine short fibers that differ in terms of fiber diameter, or aggregates thereof and / or fiber diameter It is also possible to supply to the nozzle while continuously or discontinuously changing the blending amount of thick fibers or their aggregates that differ in terms of point. If it changes in this way, the powder fixed non-woven fabric which has the layer or area | region from which an apparent density differs in the thickness direction by the difference in a fiber diameter can be manufactured. It is also possible to supply to the nozzle while continuously or discontinuously changing the blending amount of two or more kinds of powders that differ in average particle size and / or composition.
[0059]
The sheet-adhered nonwoven fabric provided with the preferred fall-off preventing layer as described above, or the sheet material of the present invention including the powder-fixed nonwoven fabric layer and the drop-off preventing layer is, for example, firstly a collection of ultrafine short fibers. A body (particularly a bundle-like aggregate) or a group of those aggregates (particularly, an aggregate group including a plurality of bundle-like aggregates in a bundle), and / or the above-mentioned finely divided mechanically Splitting fibers capable of generating short fibers, or aggregates thereof (particularly bundled aggregates) are gas from a nozzle by the action of a compressed gas in the same manner as described above under conditions that do not contain powder. After spun in and accumulated to form a fiber web composed of ultrafine short fibers, the meltability of ultrashort fibers can be used, entangled by a fluid flow such as a water stream, or a combination of these After forming a non-woven fabric that is a drop-off prevention layer, the same method as described above is applied. What, after a powder and ultra-fine short fibers were integrated on the nonwoven fabric can be manufactured by fixing the powder. In the case where a non-woven fabric made of ultrafine short fibers (a fall-off preventing layer) is arranged on both sides of the layer to which the powder is fixed, the powder is subsequently treated in the same manner as the method for forming the nonwoven fabric as the fall-off preventing layer. It can manufacture by forming the nonwoven fabric which is a drop-off prevention layer on the layer which adhered.
[0060]
In addition, after forming a fiber web from ultrafine short fibers by a normal wet method, the nonwoven fabric is produced by utilizing the fusing properties of ultrafine short fibers, entangled by a fluid flow such as a water flow, or a combination thereof. Or after preparing a nonwoven fabric obtained by a melt-blowing method, a fiber web containing fibers that can be mechanically divided by a dry method or a wet method, and entangled by a fluid flow such as a water flow, etc. After the powder and the ultra-short fibers are accumulated on the nonwoven fabric by the same method as described above on the nonwoven fabric acting as a drop-off preventing layer, the powder can be fixed and manufactured. In addition, when arrange | positioning a nonwoven fabric (fall-off prevention layer) on both sides of the layer to which the powder adhered, it can manufacture by laminating and integrating the same nonwoven fabric as the nonwoven fabric constituting the fall-off prevention layer.
In addition, when arrange | positioning a fall-off prevention layer on the both sides of the layer which the powder adhered, both fall-off prevention layers may have the same structure and material, or different structures and materials.
[0061]
When forming the powder-containing fiber web by accumulating the dispersed ultrafine short fibers and the dispersed powder, the dispersed ultrafine short fibers and the dispersed powder are used as a reinforcing material (for example, yarn, net, woven fabric, knitted fabric). , Fiber web, or ordinary nonwoven fabric) to form a laminate. Since the strength of the powder-fixed nonwoven fabric can be improved by using the laminate as described above, the powder-fixed nonwoven fabric of the present invention can be applied to uses that require strength. In addition, after forming the powder-fixed non-woven fabric according to the present invention, the powder-fixed non-woven fabric is integrated with the reinforcing material as described above (for example, yarn, net, woven fabric, knitted fabric, fiber web, normal non-woven fabric, or film). The same effect can be produced by forming a laminated body.
[0062]
Next, a manufacturing apparatus that can be used for manufacturing the powder-fixed nonwoven fabric of the present invention will be described with reference to FIG. In addition, the case where the aggregate (especially bundle-shaped aggregate) of the ultrafine short fiber whose fiber diameter is 4 micrometers or less and whose fiber length is 3 mm or less is demonstrated. FIG. 1 is a schematic explanatory view of one embodiment of a powder-fixed nonwoven fabric manufacturing apparatus used in the present invention.
[0063]
First, a bundle of aggregates of powder and ultrafine short fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less are charged into a mixing apparatus 10 such as a mixer together with thick fibers or their aggregates. Then, the bundle aggregate is divided into smaller bundle aggregates, the ultrafine short fibers are dispersed, unraveled, or mixed.
[0064]
Subsequently, the ultrafine short fibers and / or bundles of ultrafine short fiber aggregates (also thick fibers and / or aggregates in some cases) mixed with the powder are supplied from the mixing apparatus 10 to the supply pipe 11. Is supplied to the nozzle 30 via For the transfer, an appropriate carrier gas supplied from a carrier gas supply device (not shown) provided in the mixing device 10 can also be used. A compressed gas is introduced into the supply pipe 11 from the compressed gas introduction port 20 before the nozzle 30. Due to the action of the compressed gas, the bundle of ultrafine short fiber aggregates (in some cases, thick fibers and / or aggregates thereof) move together with the powder from the mixing device 10 to the nozzle 30 via the supply pipe 11. Further, the nozzle 30 is vigorously ejected into the gas 40 a in the dispersion chamber 40. When ejected into the gas 40a, the bundle 30 is formed by an interaction such as the pressure difference between the nozzle 30 and the gas 40a and the turbulent flow formed between the ejected compressed gas and the gas 40a. Ultrafine short fibers 70 are generated from the fiber assembly and are dispersed in the dispersion chamber 40 together with the powder 70a. Furthermore, the ultrafine short fibers 70 and the powder 70a ejected from the nozzle 30 are collided with the wall 45 of the dispersion chamber 40 to promote the division and dispersion of the ultrafine short fibers 70, and also to promote the dispersion of the powder 70a. it can. In this case, the wall portion 45 can act as a collision member. Further, a collision member can be separately provided between the nozzle 30 and the wall portion 45. The distance between the jet port of the nozzle 30 and the flat part (collision part) of the collision member is preferably 1 to 100 mm, more preferably 5 to 40 mm, more preferably 5 to 30 mm, more preferably 10 to 30 mm, most preferably. 10-20 mm.
[0065]
The ultra-short fibers 70 and the powder 70a dispersed in the gas 40a in the dispersion chamber 40 descend in the dispersion chamber 40 and accumulate on the support 50 made of a net provided at the bottom of the dispersion chamber 40. The containing fiber web 80 is formed. In the manufacturing apparatus used in the present invention, as shown in FIG. 1, a gas suction device 60 can be provided below the support 50 at the bottom of the dispersion chamber 40, and the gas suction device 60 allows the gas 40 a in the dispersion chamber 40 to be provided. And the accumulation of the ultrafine short fibers 70 and the powder 70a can be promoted. The inside of the dispersion chamber 40 and the outside of the dispersion chamber 40 can be airtight or not airtight.
[0066]
The support 50 on which the powder-containing fiber web 80 is accumulated rotates in an endless belt shape, and conveys the powder-containing fiber web 80 in the direction of the supply pipes 12 and 13 (the direction of arrow a in FIG. 1). Subsequently, the powder-containing fiber web 80 is supplied again to the nozzles 31 and 32 via the supply pipes 12 and 13. As shown in FIG. 1, not only can two nozzles be re-supplied, but one nozzle can be re-supplied or more than two nozzles can be re-supplied. Or when sufficient dispersion | distribution is performed, it can also transfer to the heat sealing | fusion apparatus 90 mentioned later, and can also send directly to a joining process.
[0067]
Also in the supply pipes 12 and 13, compressed gas is introduced from the compressed gas introduction ports 21 and 22, respectively, before the nozzles 31 and 32. The supplied ultra-fine short fibers (also thick fibers in some cases) and the powder move to the nozzles 31 and 32 through the supply pipes 12 and 13, and further vigorously from the nozzles 31 and 32, in the dispersion chambers 41 and 42. It is ejected into the gases 41a and 42a. At this time, similarly, the ultrafine short fibers 71 and 72 and the powders 71a and 72a are uniformly dispersed. Further, dispersion can be promoted by causing the ultrashort fibers 71 and 72 and the powders 71 a and 72 a ejected from the nozzles 31 and 32 to collide with the wall portions 46 and 47 of the dispersion chambers 41 and 42. In this case, the walls 46 and 47 can act as a collision member. Further, a collision member can be separately provided between the nozzles 31 and 32 and the wall portions 46 and 47.
[0068]
The ultrafine fibers 71 and 72 and the powders 71a and 72a dispersed in the gases 41a and 42a in the dispersion chambers 41 and 42 descend in the dispersion chambers 41 and 42, respectively, and are common to the bottoms of the dispersion chambers 41 and 42. Are accumulated on a support 51 made of a net. That is, the ultra-short fibers 71 and the powder 71a dispersed in the gas 41a in the dispersion chamber 41 descend in the dispersion chamber 41 and accumulate on the support 51 to form a single layer powder-containing fiber web 81. After that, it is conveyed together with the endless belt-like support 51 in the direction of the dispersion chamber 42 (direction of arrow b in FIG. 1). Further, the ultra-short fibers 72 and the powder 72 a dispersed in the gas 42 a in the dispersion chamber 42 descend in the dispersion chamber 42 and further accumulate on the single-layer powder-containing fiber web 81 on the support 51. Thus, a laminated powder-containing fiber web 82 is formed. However, the laminated powder-containing fiber web 82 formed in this manner does not have a clear two-layer structure because the ultra-short fibers constituting the single-layer powder-containing fiber web 80 are dispersed again.
[0069]
In the manufacturing apparatus used in the present invention, as shown in FIG. 1, a gas suction device 61 can also be provided below the support 51 at the bottom of the dispersion chambers 41, 42, and the gas suction device 61 allows the dispersion chamber 41, The gas 41a and 42a in 42 can be attracted | sucked, and accumulation | storage of the ultrafine short fibers 71 and 72 and powder 71a, 72a can be accelerated | stimulated. Further, as shown in FIG. 1, the support 51 and the gas suction device 61 can be provided in common for a plurality of dispersion chambers, or can be provided independently for each of the plurality of dispersion chambers. .
[0070]
Subsequently, the laminated powder-containing fiber web 82 is conveyed to the heat-sealing device 90 by the endless belt-like support 51, and the ultra-short fiber and / or the powder is heated by the heat-sealing device 90 by the action of heat. In some cases, the thick fibers can be fused to form the powder-fixed nonwoven fabric 83. The powder-fixed nonwoven fabric 83 is wound up by the winding device 100.
[0071]
The sheet material according to the present invention contains at least one powder-fixed nonwoven fabric layer. That is, the sheet material according to the present invention is composed of a single layer of the powder-fixed nonwoven fabric layer, or one or more powder-separated nonwoven fabric layers and one or more powder fall-off preventing layers ( Preferably one or two layers) or one or more reinforcing layers. Examples of the reinforcing layer include a normal yarn layer, a net layer, a woven fabric layer, a knitted layer, a fiber web layer, or a normal nonwoven fabric layer. The sheet material including the powder-fixed non-woven fabric layer and the reinforcing layer includes, for example, a powder-containing fiber web accumulated on the reinforcing layer, and the powder-containing fiber web and the reinforcing layer bonded to each other. The reinforcing layer and the powder-fixed nonwoven fabric layer can be bonded together by an appropriate bonding means.
Since the sheet material according to the present invention contains the powder-fixed non-woven fabric layer, it can be advantageously used in the field of utilizing various characteristics of powder. For example, an ozone decomposition sheet for an electrophotographic apparatus, a toilet deodorizer, or an ozone generator; an ion exchange sheet such as an ion exchange water purifier; a catalyst sheet such as an automobile or a chemical reaction apparatus; Deodorizing or deodorizing sheets for daily use, sanitary products, filters, shoes, etc .; fiber reinforced plastic (FRP) and sheet prepreg (SMC); or fireproof boards.
[0072]
【Example】
EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but these do not limit the scope of the present invention.
[Example 1]
There were 25 island components made of polypropylene in the sea component made of polylactic acid, and sea island type fibers (fineness = 1.7 dtex; fiber length cut to 1 mm) obtained by the composite spinning method were prepared. This sea-island type fiber is immersed in a 10 mass% sodium hydroxide aqueous solution, and polylactic acid, which is a sea component, is extracted and removed by hydrolysis, and then air-dried to produce polypropylene ultrafine fibers (fiber diameter = 2 μm; fiber length = 1 mm). Non-fibrillated; stretched; having substantially the same diameter in the fiber axis direction; adhesion rate of deposit = less than 0.02 mass%) to obtain an aggregate of ultrafine short fibers A bundled It was.
[0073]
In addition, there are 25 island components composed of high-density polyethylene and polypropylene in the sea component composed of polylactic acid, and sea island-type fibers (fineness = 1.7 dtex; fiber length 1 mm) obtained by the composite spinning method. Prepared). This sea-island type fiber is immersed in a 10 mass% sodium hydroxide aqueous solution, and polylactic acid, which is a sea component, is extracted and removed by hydrolysis, and then air-dried. Fibers (fiber diameter = 2 μm; fiber length = 1 mm; not fibrillated; stretched; have substantially the same diameter in the fiber axis direction; adherence rate = less than 0.02 mass%) are bundled An aggregate of the sea-island type ultrafine short fibers B was obtained.
[0074]
Furthermore, activated carbon having an average particle size of 6 μm was prepared as a powder.
[0075]
Subsequently, the powder fixed nonwoven fabric by this invention was prepared using the apparatus similar to the manufacturing apparatus shown in FIG. That is, after a bundle of ultrafine short fiber A aggregates, a bundle of sea-island type ultrafine short fiber B aggregates and activated carbon are supplied to a mixer at a mass ratio of 10: 5: 85, they are unwound and mixed. The venturi tube having a circular cross section at the jet outlet (diameter = 8.5 mm) is supplied to the venturi tube (the cross sectional shape on the supply side of the venturi tube = circular (diameter = 3 mm) frustum) and before the venturi tube. Compressed air in a laminar flow (pressure = 6 kg / cm ² ), And the mixture is ejected from the venturi tube into the air (gas passage speed at the venturi tube outlet = 118 m / s) and collided with a baffle plate provided in front of the venturi tube outlet. , Activated carbon, polypropylene ultrafine fiber A and sea-island ultrafine fiber B were dispersed. The distance between the venturi outlet and the baffle plate was 15 mm.
[0076]
Subsequently, the dispersed activated carbon (polypropylene ultrafine short fiber and sea-island type ultrafine short fiber) placed on a support made of a net (the basis weight is 30 g / m). ² On a polyester fiber spunbond nonwoven fabric). When accumulating, air is sucked in by a suction box installed under the support (2 m ^Three / Min).
[0077]
Next, the spunbonded nonwoven fabric substrate carrying the powder-containing fiber web is supplied to an oven set at a temperature of 130 ° C. and subjected to a heat treatment for 3 minutes to have a basis weight of 70 g / m. ² A nonwoven fabric base material laminated powder-fixed nonwoven fabric having a thickness of 1.2 mm was produced. The powder-bonded nonwoven fabric layer of this nonwoven fabric substrate laminated powder-bonded nonwoven fabric is entangled so that the polypropylene ultrafine short fiber A and the sea-island-type ultrafine fiber B surround the activated carbon powder, and the sea-island-type ultrafine short-fiber Due to the high-density polyethylene component constituting B, the polypropylene ultrafine fiber A and the sea-island-type ultrafine fiber B, and the sea-island-type ultrafine fiber B and the activated carbon powder were fused.
[0078]
In addition, when the nonwoven fabric base material was peeled from the nonwoven fabric base material laminated powder fixed nonwoven fabric thus obtained and various physical properties were measured only for the powder fixed nonwoven fabric, the basis weight was 40 g / m. ² Thickness is 1.1mm, apparent density is 0.036g / cm ^Three And the mass ratio of the ultrafine short fibers A and B was 15 mass%. Also, the mass of the powder-fixed nonwoven fabric of the total amount of adhered substances extracted from the powder-fixed nonwoven fabric immersed in hot water for 15 minutes and the deposit extracted by immersion in hot methanol for 15 minutes. The percentage (adhesion rate of deposits) with respect to was less than 0.02 mass%.
[0079]
A filter unit (peak height = 20 mm, pitch = 2 mm) was prepared by pleating the nonwoven fabric base material laminated powder-fixed nonwoven fabric, and air containing toluene at a concentration of 25 ppm was supplied at a surface wind speed of 14 cm / sec. The toluene removal rate at the outlet of the filter unit showed a high deodorization performance of 99% or more. Further, even when vibration was applied, the activated carbon did not fall off from the nonwoven fabric substrate laminated powder-fixed nonwoven fabric.
[0080]
[Example 2]
A bundle of ultrafine fiber A aggregates and a bundle of sea-island ultrafine fiber B aggregates produced in the same manner as in Example 1 were prepared. Moreover, electrolytic manganese dioxide powder (average particle size = 3 μm) was prepared as a powder.
[0081]
Next, as in Example 1, a powder-fixed nonwoven fabric according to the present invention was prepared using an apparatus similar to the manufacturing apparatus shown in FIG. That is, a bundle of ultrafine short fiber A aggregates, a bundle of sea-island ultrafine fiber B aggregates, and electrolyte manganese dioxide powder are supplied to a mixer at a mass ratio of 6: 9: 85, and these are unraveled. After mixing, the mixture is supplied to a continuously tapered tapered nozzle having a circular cross-sectional shape (diameter = 3.2 mm) at the ejection port, and a layer is formed from a compressed gas inlet provided in front of the tapered nozzle. Flow of compressed air (pressure = 6kg / cm ² ) And the mixture is ejected from the tapered nozzle into the air of the dispersion chamber (gas passing speed at the outlet of the tapered nozzle = 1600 m / s), and the polypropylene ultrafine fiber A, sea-island ultrafine fiber B and Electrolyte manganese dioxide powder was dispersed in a dispersion chamber.
[0082]
Subsequently, the dispersed electrolyte manganese dioxide powder, polypropylene ultrafine short fiber A, and sea-island type ultrafine short fiber B were placed on a support made of a net (weight is 30 g / m). ² A polyester fiber spunbond nonwoven fabric) to form a powder-containing fiber web-nonwoven fabric base material composite. When accumulating, air is sucked in by a suction box installed under the support (2 m ^Three / Min).
[0083]
Subsequently, this powder-containing fiber web-nonwoven fabric base material composite material is supplied to an oven set at a temperature of 130 ° C. and subjected to a heat treatment for 3 minutes to have a basis weight of 90 g / m. ² A nonwoven fabric base material laminated powder-fixed nonwoven fabric having a thickness of 1.0 mm was produced. The powder-bonded nonwoven fabric layer of this nonwoven fabric base material laminated powder-bonded nonwoven fabric is intertwined with the polypropylene ultrafine short fiber A and the sea-island type ultrafine fiber B so as to surround the electrolyte manganese dioxide powder, and the sea-island type ultrafine fiber layer. Due to the high density polyethylene component constituting the short fiber B, the polypropylene ultrafine short fiber A and the sea-island type ultrafine short fiber B, and the sea island type short fiber B and the electrolyte manganese dioxide powder were fused.
[0084]
In addition, when the nonwoven fabric base material was peeled from the nonwoven fabric base material laminated powder fixed nonwoven fabric and various physical properties were measured only for the powder fixed nonwoven fabric, the basis weight was 60 g / m. ² Thickness is 0.9mm, apparent density is 0.067g / cm ^Three And the mass ratio of the ultrafine short fibers A and B was 15 mass%. Also, the mass of the powder-fixed nonwoven fabric of the total amount of adhered substances extracted from the powder-fixed nonwoven fabric immersed in hot water for 15 minutes and the deposit extracted by immersion in hot methanol for 15 minutes. The percentage (adhesion rate of deposits) with respect to was less than 0.02 mass%.
[0085]
This nonwoven fabric base material laminated powder-fixed nonwoven fabric was pressed with an area calendar (temperature = 130 ° C.) to a thickness of 0.3 mm, and then corrugated (peak height = 2 mm, pitch = 1.5 mm), When ozone gas having a concentration of 10 ppm was passed through, the ozone concentration at the outlet had dropped to 0.1 ppm or less, indicating excellent ozone decomposition performance. Further, even when vibration was applied, the electrolyte manganese dioxide powder was not observed to fall off from the nonwoven fabric substrate laminated powder-fixed nonwoven fabric.
[0086]
[Example 3]
There are 61 island components made of crystalline polystyrene in the sea component made of copolyester, and the sea island type fiber obtained by the composite spinning method (fineness = 2.3 dtex; fiber length cut to 0.5 mm) Prepared. This sea-island type fiber is immersed in a 10 mass% sodium hydroxide aqueous solution, and the copolymerized polyester, which is a sea component, is extracted and removed by hydrolysis, and then air-dried to produce crystalline polystyrene ultrafine short fibers (fiber diameter = 1.1 μm) Fiber length = 0.5 mm; not fibrillated; stretched; having substantially the same diameter in the fiber axis direction; adherence rate of adherent = less than 0.02 mass%) An aggregate of fibers C was obtained.
[0087]
In addition, bundles of ultrafine short fibers B manufactured in the same manner as in Example 1 and spherical alumina powder (average particle size = 25 μm) were prepared as powders.
[0088]
Subsequently, the powder fixed nonwoven fabric by this invention was prepared using the apparatus similar to the manufacturing apparatus shown in FIG. That is, a bundle of ultrafine short fiber C aggregates, a bundle of ultrafine short fiber B aggregates, and spherical alumina powder are supplied to a mixer at a mass ratio of 1: 1: 98, After mixing and mixing, the mixture is supplied to a continuously tapered tapered nozzle having a circular cross-sectional shape (diameter = 3.2 mm) at the ejection port, and a compressed gas inlet provided in front of the tapered nozzle To laminar compressed air (pressure = 6 kg / cm ² ) And the mixture is ejected from the tapered nozzle into the air of the dispersion chamber (gas passage speed at the outlet of the tapered nozzle 30 = 1600 m / s), and the crystalline polystyrene ultrafine fiber C, the sea-island ultrafine fiber Fiber B and spherical alumina were dispersed in a dispersion chamber.
[0089]
Subsequently, the dispersed crystalline polystyrene ultrafine short fiber C, sea-island type ultrafine short fiber B, and spherical alumina were placed on a support made of a net (weighing 30 g / m). ² A polyester fiber spunbond nonwoven fabric) to form a powder-containing fiber web-nonwoven fabric base material composite. When accumulating, air is sucked by a suction box installed under the support (2 m ^Three / Min).
[0090]
Subsequently, this powder-containing fiber web-nonwoven fabric base material composite material is supplied to an oven set at a temperature of 130 ° C. and subjected to a heat treatment for 3 minutes to have a basis weight of 410 g / m. ² The nonwoven fabric base material laminated powder fixed nonwoven fabric having a thickness of 0.55 mm was manufactured. This non-woven fabric substrate laminated powder-fixed non-woven fabric powder-bonded non-woven fabric layer is intertwined with crystalline polystyrene ultrafine short fibers C and sea-island type ultrafine short fibers B so as to surround the spherical alumina. Due to the high-density polyethylene component constituting the short fiber B, the crystalline polystyrene ultrafine short fiber C and the sea-island type ultrafine short fiber B, and the sea-island type ultrafine short fiber B and the spherical alumina were fused.
[0091]
In addition, when the nonwoven fabric base material was peeled from the nonwoven fabric base material laminated powder-fixed nonwoven fabric and various physical properties were measured only for the powder-fixed nonwoven fabric, the basis weight was 380 g / m. ² , Thickness is 0.45mm, apparent density is 0.844g / cm ^Three And the mass ratio of the ultrafine short fiber was 2 mass%. Also, the mass of the powder-fixed nonwoven fabric of the total amount of adhered substances extracted from the powder-fixed nonwoven fabric immersed in hot water for 15 minutes and the deposit extracted by immersion in hot methanol for 15 minutes. The percentage (adhesion rate of deposits) with respect to was less than 0.02 mass%.
[0092]
Four of these powder-adhered non-woven fabric layers are stacked and pressed with a hot press at a temperature of 130 ° C. (pressure = 50 kg / cm ² ), A flexible sheet having a high alumina filling rate and high thermal conductivity (weight per unit: 1520 g / m) ² Thickness = 0.75 mm; apparent density = 2.03 g / cm ^Three )was gotten. This sheet was excellent in handleability and strength, with no alumina falling off.
[0093]
[Example 4]
A commercially available polyester ultra-short fiber (fiber diameter = 3.2 μm; fiber length = 3.0 mm; manufactured by Teijin) was prepared, and the fiber oil adhering to the fiber surface was extracted and removed in acetone.
[0094]
In addition, a bundle of ultrafine short fiber A aggregates and a bundle of ultrafine short fiber B aggregates produced in the same manner as in Example 1 were prepared.
Furthermore, spherical alumina powder (average particle size = 25 μm) was prepared as a powder.
[0095]
Next, using an apparatus similar to the manufacturing apparatus shown in FIG. 1, polyester ultrafine short fibers, bundled ultrafine short fiber A aggregates, bundled sea-island ultrafine short fiber B aggregates, and spherical alumina powder 2 : 2: 4: 92 is supplied to the mixer at a mass ratio, and after unraveling and mixing, these mixtures are continuously tapered with a circular cross-sectional shape (diameter = 3.2 mm) at the jet outlet. While supplying to the nozzle, laminar compressed air (pressure = 6 kg / cm) from the compressed gas inlet provided in front of the tapered nozzle ² ) And the mixture is ejected from the tapered nozzle into the air of the dispersion chamber (gas passing speed at the outlet of the tapered nozzle = 1600 m / s), and the polyester ultrafine fiber, ultrafine short fiber A, sea-island ultrafine Short fibers B and spherical alumina powder were dispersed.
[0096]
Next, the dispersed polyester substrate (polypropylene microfiber A, sea-island microfiber B, and spherical alumina powder were placed on a support made of a net (weighing 30 g). / M ² A polyester fiber spunbond nonwoven fabric) to form a powder-containing fiber web-nonwoven fabric base material composite. When accumulating, air is sucked in by a suction box installed under the support (2 m ^Three / Min).
[0097]
Next, this powder-containing fiber web-nonwoven fabric base material composite material is supplied to an oven set at a temperature of 130 ° C. and subjected to a heat treatment for 3 minutes to have a basis weight of 450 g / m. ² A non-woven fabric substrate laminated powder-fixed non-woven fabric having a thickness of 0.65 mm was produced. The non-woven fabric base material laminated powder-fixed non-woven fabric powder-bonded non-woven fabric layer is intertwined so that the polyester ultrafine short fiber, polypropylene ultrafine short fiber A and sea-island type ultrafine short fiber B surround the spherical alumina powder. The ultra-short short fibers and the sea-island ultra-short fibers B and the spherical alumina were fused by the high-density polyethylene component constituting the sea-island ultra-short fibers B.
[0098]
In addition, when the nonwoven fabric base material was peeled from the nonwoven fabric base material laminated powder-fixed nonwoven fabric and various physical properties were measured only for the powder-fixed nonwoven fabric, the basis weight was 420 g / m. ² , Thickness is 0.55mm, apparent density is 0.764g / cm ^Three And the mass ratio of the ultrafine short fiber was 8 mass%. Also, the mass of the powder-fixed nonwoven fabric of the total amount of adhered substances extracted from the powder-fixed nonwoven fabric immersed in hot water for 15 minutes and the deposit extracted by immersion in hot methanol for 15 minutes. The percentage (adhesion rate of deposits) with respect to was less than 0.02 mass%.
[0099]
Two of these powder-fixed nonwoven fabrics are stacked and pressed with a hot press at a temperature of 130 ° C. (pressure = 50 kg / cm). ² ), A flexible sheet with a high alumina filling rate and high thermal conductivity (weight per unit = 840 g / m) ² Thickness = 0.43 mm; apparent density = 1.95 g / cm ^Three )was gotten. This sheet was excellent in handleability and strength, with no alumina falling off.
[0100]
[Example 5]
About 3900 island components made of poly-4-methylpentene exist in the sea component made of copolymer polyester, and the sea island type fiber obtained by the mixed spinning method (fineness = 8.8 dtex; cut to 0.5 mm fiber length) Prepared). This sea-island type fiber is immersed in a 10 mass% sodium hydroxide aqueous solution, and the copolyester, which is a sea component, is extracted and removed by hydrolysis, then air-dried, and poly-4-methylpentene ultrafine fiber (fiber diameter = 0.4 μm; fiber length = 0.5 mm; not fibrillated; stretched; diameter changed in fiber axis direction; adherence rate of adherent = less than 0.02 mass%) was bundled An assembly of poly-4-methylpentene ultrafine short fibers D was obtained.
[0101]
In addition, an aggregate of crystalline polystyrene ultrafine fibers C produced in the same manner as in Example 3 and an aggregate of sea-island type ultrafine fibers B in the form of bundles produced in the same manner as in Example 1 were prepared.
[0102]
Next, using an apparatus similar to the manufacturing apparatus shown in FIG. 1, an aggregate of bundled poly-4-methylpentene ultrafine fibers D, an aggregate of crystalline polystyrene ultrafine fibers C, and sea-island ultrafine fibers After the aggregate of the short fibers B is fed to the mixer at a mass ratio of 40:20:40, the fibers are unwound and mixed, and then the cross-sectional shape of the mixture is circular (diameter = 3.2 mm) at the outlet. ) Continuously to the tapered nozzle, and laminar compressed air (pressure = 6 kg / cm) from the compressed gas inlet provided in front of the tapered nozzle. ² ), And the mixture is ejected from the tapered nozzle into the air of the dispersion chamber (gas passing speed at the outlet of the tapered nozzle = 1600 m / s) to obtain poly-4-methylpentene ultrafine short fiber D, crystallinity The polystyrene ultrafine short fiber C and the sea-island type ultrafine short fiber B were dispersed.
[0103]
Subsequently, the dispersed poly-4-methylpentene ultrashort fiber D, crystalline polystyrene ultrashort fiber C, and sea-island type ultrashort fiber B were placed on a support made of a net. (Weight is 30 g / m ² On a polyester fiber spunbond nonwoven fabric), and an ultrafine short fiber web (drop-off preventing layer; basis weight = 5 g / m) ² ) -Nonwoven fabric substrate composite was formed. When accumulating, air is sucked in by a suction box installed under the support (2 m ^Three / Min).
[0104]
Next, an assembly of poly-4-methylpentene ultrashort fibers D in the same bundle as described above, an assembly of crystalline polystyrene ultrafine fibers C produced in the same manner as in Example 3, and the same as in Example 1 An anatase-type titanium dioxide powder (average particle size = 0.2 μm) was prepared as an aggregate of the sea-island ultrafine fibers B manufactured as described above and as a powder.
[0105]
Next, an assembly of poly-4-methylpentene ultrafine fibers D, an aggregate of crystalline polystyrene ultrafine fibers C, an aggregate of sea-island ultrafine fibers B, and anatase-type titanium dioxide powder were obtained at 3: 6: 6. The mixture is fed to a mixer at a mass ratio of 85, and after these are unwound and mixed, the mixture is fed to a continuously tapered taper nozzle having a circular cross-sectional shape (diameter = 3.2 mm) at the jet nozzle. At the same time, compressed air in a laminar flow (pressure = 6 kg / cm) from a compressed gas inlet provided in front of the tapered nozzle ² ), And the mixture is ejected from the tapered nozzle into the air of the dispersion chamber (gas passing speed at the outlet of the tapered nozzle = 1600 m / s), and titanium dioxide powder, poly-4-methylpentene ultrafine fiber Crystalline polystyrene ultrafine short fibers and sea-island type ultrafine short fibers were dispersed.
[0106]
Subsequently, the dispersed poly-4-methylpentene ultrafine fiber D, crystalline polystyrene ultrafine fiber C, sea-island type ultrafine fiber B, and titanium dioxide powder are mixed with the ultrafine fiber web (drop-off prevention layer; basis weight). = 5 g / m ² )-The non-woven fabric substrate composite was collected on an ultrafine short fiber web to form a powder-containing fiber web-ultrafine short fiber web-nonwoven fabric substrate composite. When accumulating, air is sucked in by a suction box installed under the support (2 m ^Three / Min).
[0107]
Next, in the same manner as described above, an aggregate of poly-4-methylpentene ultrafine fibers D, an aggregate of crystalline polystyrene ultrafine fibers C, and an aggregate of sea-island type ultrafine fibers B are dispersed and dispersed. The powder-containing fiber web-ultrafine short fiber web-nonwoven substrate composite material collected on the powder-containing fiber web, the ultrafine fiber web-powder-containing fiber web-ultrafine fiber web-nonwoven substrate A composite was formed.
[0108]
Next, this ultrafine fiber web-powder-containing fiber web-ultrafine short fiber web-nonwoven fabric base material composite material is supplied to an oven set at a temperature of 130 ° C. and subjected to a heat treatment for 3 minutes to have a basis weight of 270 g / m. ² The nonwoven fabric base material laminated powder fixed nonwoven fabric having a thickness of 0.42 mm was manufactured. The powder-bonded nonwoven fabric layer of this nonwoven fabric base material laminated powder-bonded nonwoven fabric comprises poly-4-methylpentene ultrafine short fiber D, crystalline polystyrene ultrafine short fiber C, and sea-island type ultrafine short fiber B around titanium dioxide powder. While being intertwined so as to surround, the high-density polyethylene component constituting the sea-island-type ultrafine short fiber B was in a state where the ultrashort fibers and the sea-island-type ultrafine short fiber B and titanium dioxide were fused. Moreover, it was in the state which can prevent dropping of titanium dioxide powder by the fiber layer (drop-off prevention layer) derived from the ultra-fine short fiber web consisting only of ultra-fine short fibers.
[0109]
In addition, when the nonwoven fabric base material was peeled from the nonwoven fabric base material laminated powder fixed nonwoven fabric and various physical properties were measured only for the three-layer structure powder fixed nonwoven fabric, the basis weight was 240 g / m. ² The thickness is 0.32 mm and the apparent density is 0.750 g / cm. ^Three Thus, the mass ratio of the ultrafine short fibers in the powder-fixed nonwoven fabric layer was 15 mass%. In addition, the three-layer structure of the total amount of adhering substances of the adhering material extracted by immersing the three-layer structure powder-fixed nonwoven fabric in hot water for 15 minutes and the adhering material extracted by immersing in hot methanol for 15 minutes The percentage with respect to the mass of the powder-fixed nonwoven fabric (adhesion rate of deposits) was less than 0.02 mass%.
[0110]
A filter unit (crest height = 20 mm; pitch = 2 mm) is prepared by pleating the nonwoven fabric base material laminated powder-fixed nonwoven fabric, and air containing toluene at a concentration of 100 ppb is irradiated while irradiating the filter unit with ultraviolet rays. When it was passed at a speed of 20 cm / s, the toluene removal rate at the outlet of the filter unit reached 80%. Further, even when vibration was applied to this nonwoven fabric base material laminated powder-fixed nonwoven fabric, the titanium dioxide powder was not observed to fall off.
[0111]
[Example 6]
A bundle of bundled sea-island type ultrafine short fibers B produced in the same manner as in Example 1 was prepared.
[0112]
Next, the sea-island type ultrafine fiber B aggregate is supplied to a mixer and unraveled, and then the sea-island type ultrafine short fiber B aggregate is continuously rounded in cross-sectional shape (diameter = 3.2 mm) at the outlet. In addition to being supplied to the tapered nozzle, the laminar compressed air (pressure = 6 kg / cm) is introduced from the compressed gas inlet provided in front of the tapered nozzle. ² ) And the mixture was ejected from the tapered nozzle into the air of the dispersion chamber (gas passage speed at the outlet of the tapered nozzle = 1600 m / s) to disperse the sea-island ultrafine fibers B.
[0113]
Next, this dispersed sea-island type ultrafine short fiber B was placed on a support made of a net (non-woven fabric base material having a basis weight of 30 g / m). ² On a polyester fiber spunbond nonwoven fabric), and an ultrafine short fiber web (weight per unit: 5 g / m) ² ) -Nonwoven fabric substrate composite was formed. When accumulating, air is sucked in by a suction box installed under the support (2 m ^Three / Min).
[0114]
Subsequently, a bundle of sea-island type ultrafine short fibers B produced in the same manner as in Example 1 and a low-density polyethylene powder (average particle size = 12 μm; manufactured by Sumitomo Seika Co., Ltd.) as a powder Prepared.
[0115]
Next, the sea-island-type ultrafine short fiber B aggregate and the low-density polyethylene powder are supplied to the mixer at a mass ratio of 5:95, and after being unraveled and mixed, the cross-sectional shape at the outlet is circular ( Supplying continuously to a tapered nozzle with a diameter = 3.2 mm), and laminar compressed air (pressure = 6 kg / cm) from a compressed gas inlet provided in front of the tapered nozzle ² ) And the mixture is ejected from the tapered nozzle into the air of the dispersion chamber (gas passage speed at the outlet of the tapered nozzle = 1600 m / s) to disperse the low-density polyethylene powder and the sea-island ultrafine fiber B I let you.
[0116]
Subsequently, the dispersed low-density polyethylene powder and the sea-island type ultrafine fiber B are mixed with the ultrafine short fiber web (weight per unit = 5 g / m). ² ) -A non-woven fabric base composite material was accumulated on an ultrafine short fiber web to form a powder-containing fiber web-superfine short fiber web-nonwoven fabric base composite. When accumulating, air is sucked in by a suction box installed under the support (2 m ^Three / Min).
[0117]
Subsequently, this powder-containing fiber web-ultrafine short fiber web-nonwoven fabric base material composite material is supplied to an oven set at a temperature of 107 ° C. and subjected to a heat treatment for 5 minutes to have a basis weight of 118 g / m. ² The nonwoven fabric base material laminated powder fixed nonwoven fabric having a thickness of 0.55 mm was manufactured. This non-woven fabric base material laminated powder-fixed non-woven fabric is entangled so that the sea-island-type ultrafine short fibers B surround the low-density polyethylene powder, and the high-density polyethylene component and the low-density constituting the sea-island-type ultrafine short fibers B A part of the polyethylene powder was melted, and the sea-island ultrafine fibers B and the sea-island ultrafine short fibers B and the low-density polyethylene powder were fused. Further, the fiber layer (drop-off preventing layer) derived from the ultra-short fiber web composed only of the sea-island ultra-short fibers B was in a state where the low-density polyethylene resin powder could be prevented from falling off.
[0118]
The two-layer structure powder-fixed non-woven fabric was peeled from the non-woven fabric substrate laminated powder-fixed non-woven fabric, and various physical properties were measured only for the two-layer structure powder-fixed non-woven fabric. The basis weight was 88 g / m. ² The thickness is 0.45mm and the apparent density is 0.196g / cm ^Three And the mass ratio of the ultrafine short fiber in a powder fixed nonwoven fabric layer was 5 mass%. Moreover, this two-layer structure powder-fixed nonwoven fabric was such that the low density polyethylene powder did not fall off. Furthermore, the two-layer structure of the total amount of adhering substances of the adhering substance extracted by immersing this two-layer structure powder fixed nonwoven fabric in hot water for 15 minutes and the adhering substance extracted by immersing in hot methanol for 15 minutes. The percentage with respect to the mass of the powder-fixed nonwoven fabric (attachment rate of deposits) was less than 0.02 mass%.
[0119]
When this two-layer structure powder-fixed nonwoven fabric was heat-treated in an oven set at 125 ° C. for 5 minutes, the low-density polyethylene powder melted to form a film, and the sea-island ultrafine fibers B were dispersed in the low-density polyethylene. , Fiber reinforced plastic (FRP) sheet with excellent flexibility and strength (weight per unit = 88 g / m ² Thickness = 0.14 mm; apparent density = 0.629 g / cm ^Three Thus, it was found that the sea-island type ultrafine short fiber B plays the role of an aggregate in the FRP.
[0120]
【The invention's effect】
The powder-fixed non-woven fabric of the present invention is less likely to fall off even if it is a powder having a small particle size, and can exhibit its original function.
When the average particle size of the powder is 50 μm or less, the function of the powder can be maximized.
When the mass ratio in the layer to which the powder of the ultrafine short fibers is fixed is 1 to 40 mass%, the amount of the powder is large, so that the function of the powder can be exhibited to the maximum.
[0121]
When the adhesion rate of the deposits adhering to the layer to which the powder is fixed is 0.5 mass% or less, the function of the powder is not inhibited by the deposits.
If a drop-off preventing layer that can prevent the powder from falling off is further provided on at least one surface of the layer to which the powder is fixed, the powder can be more reliably prevented from falling off.
According to the method for producing a powder-fixed nonwoven fabric of the present invention, powder is fixed to a fiber web formed by a non-wet method in which ultrafine short fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less are dispersed. The manufactured nonwoven fabric can be manufactured easily.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a production apparatus capable of producing a powder-fixed nonwoven fabric of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Mixing apparatus; 11, 12, 13 ... Supply pipe;
20, 21, 22 ... compressed gas inlet;
30, 31, 32 ... nozzle; 40, 41, 42 ... dispersion chamber;
40a, 41a, 42a ... gas; 45, 46, 47 ... walls of the dispersion chamber;
50, 51 ... support; 60, 61 ... gas suction device;
70, 71, 72 ... extra fine fiber;
70a, 71a, 72a ... powder; 80 ... fiber web;
81 ... single layer fiber web; 82 ... laminated fiber web;
83 ... heat-sealing nonwoven fabric; 90 ... heat-sealing device; 100 ... winding device.

Claims (13)

A powder-fixed non-woven fabric comprising a powder and an ultra-fine short fiber having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, wherein the ultra-fine short fiber is bundled over the entire powder-fixed non-woven fabric. The ultra-short fiber is not present, and is composed of an island component obtained by removing the sea component of the sea-island type fiber, and an assembly of ultra-fine short fibers or a group of these, together with powder, action of compressed gas The powder-fixed non-woven fabric formed from the powder-containing fiber web formed by a method of forming a fiber web by jetting into a gas from a nozzle .   The powder-fixed nonwoven fabric according to claim 1, wherein the powder has an average particle size of 50 μm or less.   The powder-fixed nonwoven fabric according to claim 1 or 2, wherein a mass ratio of the ultrafine short fibers to a total mass of the powder-fixed nonwoven fabric is 1 to 40 mass%.   The powder-fixed nonwoven fabric according to any one of claims 1 to 3, wherein the adhesion rate of the deposit is 0.5 mass% or less.   The powder fixed nonwoven fabric as described in any one of Claims 1-4 in which the said ultra-fine short fiber consists of an organic component. Aggregates of ultrafine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, or a group thereof, and / or ultrafine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less when mechanically divided The fine fiber bundles or their aggregates are ejected into the gas from the nozzle by the action of compressed gas together with the powder, or the aggregates thereof that can generate Splitting and / or splitting the splittable fibers or aggregates thereof into ultrafine short fibers and dispersing the powder,
Included in the powder-containing fiber web when the dispersed ultrafine short fibers and powder are accumulated to form a powder-containing fiber web, and when forming a nonwoven fabric from the obtained powder-containing fiber web Fixing the powder to be
A method for producing a powder-fixed nonwoven fabric, comprising:   The manufacturing method according to claim 6, wherein the aggregate of the ultrafine short fibers is a bundled aggregate.   Performing the deposit removal step before supplying the aggregate of the ultra-short fibers or the group of the aggregates and / or the split fibers capable of generating ultra-short fibers or the aggregate thereof to the nozzle, The manufacturing method of Claim 6 or 7.   The manufacturing method as described in any one of Claims 6-8 whose flow of the gas supplied to the said nozzle is a laminar flow substantially.   After the fine short fiber aggregates or the group of aggregates and / or the fine short fiber-producible splitting fibers or the aggregates are ejected from the nozzle together with the powder, in front of the nozzle injection port The manufacturing method as described in any one of Claims 6-9 made to collide with the provided collision member. A powder-fixed non-woven fabric comprising a powder and an ultra-fine short fiber having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, wherein the ultra-fine short fiber is bundled over the entire powder-fixed non-woven fabric. The ultra-short fiber is not present, and is composed of an island component obtained by removing the sea component of the sea-island type fiber, and an assembly of ultra-fine short fibers or a group of these, together with powder, action of compressed gas A sheet material comprising at least one layer of the powder-fixed nonwoven fabric formed from a powder-containing fiber web formed by a method of forming a fiber web by being ejected from a nozzle into a gas .   The sheet material according to claim 11, further comprising a powder-free layer on at least one surface of the powder-fixed nonwoven fabric layer. Aggregates of ultrafine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, or a group thereof, and / or ultrafine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less when mechanically divided The fine fiber bundles or their aggregates are ejected into the gas from the nozzle by the action of compressed gas together with the powder, or the aggregates thereof that can generate Splitting and / or splitting the splittable fibers or aggregates thereof into ultrafine short fibers and dispersing the powder,
Included in the powder-containing fiber web when the dispersed ultrafine short fibers and powder are accumulated to form a powder-containing fiber web, and when forming a nonwoven fabric from the obtained powder-containing fiber web Fixing the powders that are present, and simultaneously bonding the powder-free layers together with them,
A method for producing a sheet material containing a powder-fixed nonwoven fabric layer, comprising:

Images