JP3309320B2 - Filter and manufacturing method thereof - Google Patents
Filter and manufacturing method thereofInfo
- Publication number
- JP3309320B2 JP3309320B2 JP5756192A JP5756192A JP3309320B2 JP 3309320 B2 JP3309320 B2 JP 3309320B2 JP 5756192 A JP5756192 A JP 5756192A JP 5756192 A JP5756192 A JP 5756192A JP 3309320 B2 JP3309320 B2 JP 3309320B2
- Authority
- JP
- Japan
- Prior art keywords
- filter
- melting point
- fiber
- cylindrical filter
- fiber web
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Filtering Materials (AREA)
- Filtering Of Dispersed Particles In Gases (AREA)
- Nonwoven Fabrics (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、電子機器用材料の洗浄
液用フィルターや、除塵用エアフィルター、医薬品用に
用いられる水等のプレフィルター等として広く用いられ
ている精密濾過用筒状フィルター及びその製造方法に関
するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical filter for precision filtration which is widely used as a filter for washing liquid for electronic equipment, an air filter for dust removal, a prefilter for water and the like used for pharmaceuticals, and the like. The present invention relates to the manufacturing method.
【０００２】[0002]
【従来の技術】精密濾過用フィルターとしては、単一成
分からなるメルトブロー法不織布を厚み方向に密度勾配
のある状態に順次数層に巻回したもの（特開平１ー２９
７１１３号公報）等が知られている。しかしながら、前
記特開平１ー２９７１１３号公報記載のフィルターにあ
っては、あらかじめ繊維径や嵩密度の異なる数種のメル
トブロー法不織布を準備しておき、補強材を兼ねた多孔
性の中芯に該不織布を内層が密、外層が粗となるように
順次数回ずつ巻回して構成されている。従って製造方法
が複雑であり、非効率的な製法である。また該不織布は
製造時にカレンダー等により圧密加工されるため濾紙と
同様な組織となり、濾過は各不織布層の最外面における
表面濾過になり、濾過ライフが短いと言う課題がある。
また特公昭５６−２６４５２号公報には、濾紙やメンブ
レンフィルターをプリーツ加工して菊花状型にし、濾過
ライフを延長する手法を取り入れている。この方法では
絶対濾過精度の良いものが得られるが、濾過層は薄く耐
圧性に劣りかつ表面濾過であるので、濾過面積を広げて
も目詰まりを起こすのが早く、濾過ライフはやはり短い
と言う課題が残る。2. Description of the Related Art As a filter for microfiltration, a non-woven fabric composed of a single component, which is melt-blown, is sequentially wound into several layers in a state of a density gradient in the thickness direction (Japanese Patent Laid-Open No. 1-29).
No. 7113) is known. However, in the filter described in Japanese Patent Application Laid-Open No. 1-297113, several types of melt-blown nonwoven fabrics having different fiber diameters and bulk densities are prepared in advance, and the nonwoven fabric is coated on a porous core also serving as a reinforcing material. The nonwoven fabric is formed by winding several times sequentially so that the inner layer is dense and the outer layer is coarse. Therefore, the manufacturing method is complicated and inefficient. Further, since the nonwoven fabric is compacted by a calender or the like at the time of production, the nonwoven fabric has a structure similar to that of filter paper, and the filtration is surface filtration on the outermost surface of each nonwoven fabric layer, and there is a problem that the filtration life is short.
In Japanese Patent Publication No. 56-26452, a technique of pleating a filter paper or a membrane filter into a chrysanthemum flower shape to extend the filtration life is adopted. With this method, a product with high absolute filtration accuracy can be obtained, but since the filtration layer is thin and inferior in pressure resistance and is surface filtration, even if the filtration area is enlarged, clogging occurs quickly and the filtration life is still short. Challenges remain.
【０００３】[0003]
【発明が解決しようとする課題】本発明は濾過精度が高
く、耐圧性に優れかつ濾過ライフが長い精密濾過用フィ
ルタ−及びその簡便な製造方法を提供することを目的と
する。SUMMARY OF THE INVENTION An object of the present invention is to provide a filter for precision filtration having high filtration accuracy, excellent pressure resistance and a long filtration life, and a simple production method thereof.
【課題を解決するための手段】本発明者らは、上記課題
を解決すべく鋭意研究を重ねた結果、以下の構成を採用
することにより、所期の目的が達成されることを知り、
本発明を完成するに至った。即ち、本発明の一つは、平
均繊維径１０μｍ以下の繊維ウェブを主体とする筒状フ
ィルタ−であって、該筒状フィルタ−の外周面が凹凸状
に成形され、その外周面積が、外周面が平滑である筒状
フィルタ−の外周面積の１．２倍以上であることを特徴
とする筒状フィルタ−である。本発明の他の一つは、メ
ルトブロ−法紡糸により得られる繊維ウェブを中芯に巻
き取ってフィルタ−とする際に、巻き取り時及び／また
は巻き取り後に凸状型部材で押圧（以下、型付けという
ことがある）して、その外周面積を、押圧前の筒状フィ
ルタ−の外周面積の１．２倍以上にすることを特徴とす
る筒状フィルタ−の製造方法である。さらに、好ましい
態様としては、繊維ウェブを中芯に巻き取り時及び／ま
たは巻き取り後に、複合繊維の低融点成分の融点以上で
高融点成分の融点以下の温度で熱処理し、ついで型付け
する筒状フィルタ−の製造方法である。Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, have found that the intended purpose is achieved by adopting the following configuration.
The present invention has been completed. That is, one aspect of the present invention is a cylindrical filter mainly composed of a fiber web having an average fiber diameter of 10 μm or less, wherein the outer peripheral surface of the cylindrical filter is formed into an uneven shape, and the outer peripheral area thereof is set to the outer peripheral area. A cylindrical filter characterized in that the surface is at least 1.2 times the outer peripheral area of the cylindrical filter having a smooth surface. Another aspect of the present invention is that when a fiber web obtained by melt-blowing is wound around a core to form a filter, the fiber web is pressed with a convex member at the time of winding and / or after winding (hereinafter, referred to as a filter). This is a method of manufacturing a cylindrical filter, wherein the outer peripheral area of the cylindrical filter is 1.2 times or more the outer peripheral area of the cylindrical filter before pressing. Further, as a preferred embodiment, when the fibrous web is wound around the core, and / or after the winding, the heat treatment is performed at a temperature not lower than the melting point of the low melting point component and not higher than the melting point of the high melting point component of the composite fiber, and then the cylindrical shape is formed. It is a manufacturing method of a filter.
【０００４】以下本発明を詳しく説明する。本発明のフ
ィルターでは平均繊維径が１０μｍ以下の繊維を用い
る。平均繊維径が１０μｍを超えるとフィルターの濾過
精度が低下し、粒径の大きな粒子まで流出するようにな
り好ましくない。なおここで言う平均繊維径とは、フィ
ルターの断面の電顕写真を用いて測定した１００箇所の
繊維径より求めた平均値である。この様な平均繊維径が
１０μｍ以下という繊維ウェブは、メルトブロー法によ
り得ることができ、メルトブロー法による繊維は実質的
に延伸されておらず有限繊維長で構成される。本発明の
フィルターは、かかる繊維ウェブを主体とする素材で構
成されるが、本発明の効果を妨げない範囲において、繊
維状活性炭や繊維状イオン交換体等の他の機能性繊維、
あるいは粉末状の活性炭やゼオライト等の吸収剤を混入
することもできる。本発明で言う凹凸状とはフィルター
の外周面が平坦でなく、何等かの凹凸状を形成したもの
を言う。具体的な形状としては、直線状、波状、破線
状、格子状等の溝、円錐形、角錐形、円柱形、角柱形、
畝状、茸状、星状、舌状、ハート状、亀甲状、弓状、櫛
刃状、くさび状等の穴（窪み）を単独または適宜組み合
わせて、筒状フィルターの外周部に均等に配置すること
が例示できる。筒状フィルター外周面を凹凸状に成形す
る方法としては、メルトブロー法紡糸により得られる繊
維ウェブをフィルター作製用の中芯に巻き取るに際し、
巻き取り時及び／または巻き取り後にフィルターの外周
から凸状型部材で適宜加熱押圧して型付けするのであ
る。例えば繊維ウエブを巻取った表面がフラットなフィ
ルターを、エンボスロールの様な凸状の突起を有するロ
ール及び／または深溝の仕上げロールの上で回転押圧し
ながら型付けする方法がある。また、表面がフラットな
フィルターに、剣山様の押し型で２方向及びそれ以上の
方向から挟んで型付けする方法もある。凹凸状の構造
は、型付け前の筒状フィルターの外周面積を少なくとも
１．２倍以上に拡大するように、その形状、大きさ、数
等を適宜決定する。型付け後のフィルターの外周面積が
型つけ前の筒状フィルターの外周面積の１．２倍未満で
あると、フィルターの濾過ライフを長くするという効果
が得られないので好ましくない。なお、本発明のフィル
ターの好ましい態様として、前記凹凸状の構造と併せ
て、フィルターの素材として融点差の異なる２種の成分
を複合メルトブロー紡糸して得た複合繊維ウェブを用
い、ウエブの巻取り時及び／又は巻取り後に、複合繊維
の低融点成分の融点以上で高融点成分の融点以下の温度
で熱処理して、繊維の接点を低融点成分の融着により接
着させた構造とすることにより、得られるフィルターは
耐圧性が著しく向上し、一段と濾過精度が安定するよう
になる。Hereinafter, the present invention will be described in detail. In the filter of the present invention, fibers having an average fiber diameter of 10 μm or less are used. If the average fiber diameter exceeds 10 μm, the filtration accuracy of the filter decreases, and particles having a large particle diameter flow out, which is not preferable. The average fiber diameter here is an average value obtained from 100 fiber diameters measured using an electron micrograph of a cross section of the filter. Such a fiber web having an average fiber diameter of 10 μm or less can be obtained by a melt blow method, and the fibers by the melt blow method are not substantially stretched and have a finite fiber length. The filter of the present invention is composed of such a fiber web-based material, but other functional fibers such as a fibrous activated carbon and a fibrous ion exchanger, as long as the effects of the present invention are not impaired.
Alternatively, an absorbent such as powdered activated carbon or zeolite can be mixed. The unevenness referred to in the present invention refers to a filter in which the outer peripheral surface of the filter is not flat and some unevenness is formed. Specific shapes include straight, wavy, dashed, grid-like grooves, cones, pyramids, cylinders, prisms,
Ridge-shaped, mushroom-shaped, star-shaped, tongue-shaped, heart-shaped, tortoise-shaped, bow-shaped, comb-shaped, wedge-shaped holes (dents) alone or in combination as appropriate, arranged evenly on the outer periphery of the cylindrical filter Can be exemplified. As a method of forming the outer peripheral surface of the cylindrical filter into an irregular shape, when winding a fiber web obtained by melt-blowing spinning around a filter manufacturing core,
At the time of winding and / or after the winding, the filter is appropriately heated and pressed from the outer periphery of the filter with a convex mold member. For example, there is a method in which a filter obtained by winding a fiber web and having a flat surface is molded while being rotationally pressed on a roll having convex protrusions such as an embossing roll and / or a finishing roll having a deep groove. Also, there is a method in which a filter having a flat surface is sandwiched between two or more directions with a sword-shaped pressing die. The shape, size, number, and the like of the uneven structure are appropriately determined so that the outer peripheral area of the cylindrical filter before molding is increased by at least 1.2 times or more. If the outer peripheral area of the filter after the molding is less than 1.2 times the outer peripheral area of the cylindrical filter before the molding, it is not preferable because the effect of extending the filtration life of the filter cannot be obtained. As a preferred embodiment of the filter of the present invention, a web of a composite fiber obtained by subjecting two types of components having different melting points to composite melt blow spinning as a material of the filter in combination with the above-mentioned uneven structure is used, and the web is wound up. When and / or after winding, heat treatment at a temperature not lower than the melting point of the low melting point component and not higher than the melting point of the high melting point component of the composite fiber to form a structure in which the fiber contacts are bonded by fusion of the low melting point component. The resulting filter has remarkably improved pressure resistance, and the filtration accuracy is further stabilized.
【０００５】以下、本発明の好ましい態様である複合メ
ルトブロー繊維を用いた例について述べる。なお、複合
メルトブロー繊維でない場合は、原料樹脂を１種のみ用
い、後述の熱処理を省略すれば、本発明のフィルターが
得られる。複合メルトブロー法とは、２種の熱可塑性樹
脂を各々独立に溶融し複合紡糸口金に供給し、紡糸孔か
ら押し出される熱可塑性樹脂を紡糸孔の周囲より吹き出
す高速気体によって捕集用ネットコンベア上に吹き付
け、極細の複合繊維ウェブを得る方法である。複合形式
としては、芯鞘型、並列型等を例示できる。用いる気体
は、通常２ｋｇ／ｃｍ2・Ｇ、４００℃、１０ｍ3／分の
空気や、不活性ガスなどが一般的である。メルトブロ−
用口金とコンベアとは、繊維同士の融着が少ない距離に
設定され、熱可塑性樹脂の融点や高速空気流の吹き付け
条件などにより適宜調節される。通常は、約３０〜８０
ｃｍである。複合メルトブロー繊維の構造で重要なこと
は、融点の異なる２種の熱可塑性樹脂の中、低融点の成
分が繊維断面外周の少なくとも一部を占めることであ
る。低融点成分の外周を占める比率は繊維軸方向に変化
してもよく、特に限定されない。要は、後述する熱処理
によって繊維の各接点を低融点成分のみの融着により接
着し、複合繊維ウェブに三次元構造を形成させるような
複合構造であればよい。低融点成分と高融点成分の複合
比は、８０／２０〜２０／８０、好ましくは７０／３０
〜３０／７０、より好ましくは５５／４５〜４５／５５
の範囲である。本発明のフィルターの素材として用いら
れる繊維ウェブを構成する熱可塑性樹脂としては、ポリ
アミド、ポリエステル、低融点共重合ポリエステル、ポ
リビニリデンクロライド、ポリビニルアセテート、ポリ
スチレン、ポリウレタンエラストマー、ポリエステルエ
ラストマー、ポリプロピレン、ポリエチレン、共重合ポ
リプロピレン等からなる熱可塑性樹脂が例示でき、複合
紡糸する場合は融点の差が２０℃以上異なる熱可塑性樹
脂を組合わせて使用する。複合繊維の両成分の融点差が
２０℃未満であると、熱処理時に高融点成分も軟化ない
し融解して繊維形状がくずれ、ウエブがフィルム化して
しまい、フィルター内部の空隙が潰れて、通水性低下な
ど濾過性能に大きい悪影響が出て好ましくない。なお、
ここでいう融点とは、一般的には示差走査熱量計（ＤＳ
Ｃ）での測定が可能で、吸熱ピークとして現れる。非晶
性の低融点共重合ポリエステル等の場合、融点が必ずし
も明確に現れないため、一般的に言われている軟化点で
代用され、測定には示差熱分析（ＤＴＡ）等を利用す
る。複合の好ましい組み合わせとしては、ポリエチレン
／ポリプロピレン、ポリエステル／低融点共重合ポリエ
ステル、ポリエチレン／ポリエステルなど例示できる
が、これらに限定されるものではない。Hereinafter, an example using a composite meltblown fiber which is a preferred embodiment of the present invention will be described. When the fiber is not a composite meltblown fiber, the filter of the present invention can be obtained by using only one kind of raw resin and omitting the heat treatment described below. With the composite melt blowing method, two types of thermoplastic resins are independently melted and supplied to a composite spinneret, and the thermoplastic resin extruded from the spinning holes is blown out from around the spinning holes onto a collecting net conveyor by a high-speed gas. This is a method of spraying to obtain a fine composite fiber web. Examples of the composite type include a core-sheath type and a parallel type. The gas used is generally 2 kg / cm 2 · G, 400 ° C., 10 m 3 / min air, an inert gas, or the like. Melt blow
The base and the conveyor are set at a distance where the fusion of the fibers to each other is small, and is appropriately adjusted depending on the melting point of the thermoplastic resin, the blowing condition of the high-speed air flow, and the like. Usually about 30-80
cm. What is important in the structure of the composite meltblown fiber is that, of two thermoplastic resins having different melting points, a component having a low melting point occupies at least a part of the outer periphery of the fiber cross section. The ratio of the low melting point component occupying the outer periphery may vary in the fiber axis direction, and is not particularly limited. In short, any composite structure may be used as long as the contact points of the fibers are bonded by fusion of only the low melting point component by a heat treatment described later to form a three-dimensional structure on the composite fiber web. The composite ratio of the low melting point component and the high melting point component is 80/20 to 20/80, preferably 70/30.
３０30/70, more preferably 55 / 45-45 / 55
Range. The thermoplastic resin constituting the fibrous web used as a material of the filter of the present invention includes polyamide, polyester, low melting point copolymerized polyester, polyvinylidene chloride, polyvinyl acetate, polystyrene, polyurethane elastomer, polyester elastomer, polypropylene, polyethylene, and the like. A thermoplastic resin composed of a polymerized polypropylene or the like can be exemplified. In the case of composite spinning, a thermoplastic resin having a difference in melting point differing by 20 ° C. or more is used in combination. If the difference between the melting points of both components of the conjugate fiber is less than 20 ° C., the high melting point component is also softened or melted during heat treatment, the fiber shape collapses, the web becomes a film, the pores inside the filter are crushed, and the water permeability decreases. For example, it has a large adverse effect on filtration performance and is not preferable. In addition,
The melting point referred to here is generally a differential scanning calorimeter (DS
Measurement at C) is possible and appears as an endothermic peak. In the case of an amorphous low-melting-point copolyester or the like, the melting point does not always appear clearly. Therefore, a so-called softening point is used instead, and differential thermal analysis (DTA) or the like is used for measurement. Preferred combinations of composites include, but are not limited to, polyethylene / polypropylene, polyester / low melting point copolymerized polyester, polyethylene / polyester, and the like.
【０００６】熱可塑性樹脂を複合メルトブロー紡糸し
て、捕集ネットコンベア上に堆積した繊維ウェブをフィ
ルター作製用の中芯に巻き取るに際し、次の方法があ
る。ひとつは、吸引機構を備えた中空の中芯を回転させ
ながら、該中芯に直接複合メルトブローの繊維ウェブを
吹き付ける、いわゆるメルトブロー紡糸直結方式で筒状
フィルターを得る方法である。なお、この時メルトブロ
ーの熱風に強弱をつけ、繊維径をフィルターの内面から
外周面に向かって順次大きくしたり、繊維ウェブを中芯
に巻き取る際外周面をロールで押圧したりしてフィルタ
ーに密度勾配をつけてもよい。また、複合メルトブロー
紡糸によりネットコンベア上に堆積させた繊維ウェブを
一旦巻き取り、これを改めて加熱しながら中芯に巻き取
り、冷却後中芯を抜き取る方法もある。この場合は中芯
に吸引装置を具備する必要が無い。この場合も前記と同
様に繊維径を変えたり、密度勾配を付けることもでき
る。中芯の断面形状は円形の他、楕円形、三角形、四角
形、及びそれ以上の多角形でも構わないが、円形が一般
的である。本発明において、繊維ウェブの熱処理とは、
複合繊維の低融点成分の融点以上、高融点成分の融点以
下の温度で加熱し、低融点成分のみを融解して繊維の接
点を接着させ、繊維ウェブに三次元構造を形成させるこ
とをいう。熱処理の加熱源としては、熱風、過熱蒸気あ
るいは遠赤外線による加熱、あるいは熱エンボス法、熱
カレンダー法、超音波接着法等を用いることができる。
特に遠赤外加熱法は、複合メルトブロー法により得られ
たウェブを乱す事なく厚みムラが少い状態で均一に加熱
接合でき、濾過性能の安定したフィルターが得られる好
ましい方法である。熱処理の具体的な手順としては、繊
維ウエブを加熱しながら中芯に巻取る方法、あるいは繊
維ウエブを中芯に巻取った後に加熱する方法があるが、
特に限定されない。このような熱処理により繊維ウェブ
には三次元構造が形成され、フィルター内部の細孔構造
は水圧変動などでも細孔が目開きせず、かつ流体の圧力
による空隙の目詰まりを防止する。このため、フィルタ
ー層内部に多孔性支持体や補強材などを用いなくても優
れた耐圧性を示し、濾過精度が安定する。[0006] The following method is used for composite melt blow spinning of a thermoplastic resin and winding the fiber web deposited on a collecting net conveyor around a core for producing a filter. One is a method of obtaining a tubular filter by a so-called melt-blow spinning direct connection method in which a composite melt-blown fiber web is directly blown onto a hollow core provided with a suction mechanism while rotating the core. At this time, the strength of the hot air of the melt blow is applied to the filter, and the fiber diameter is gradually increased from the inner surface of the filter to the outer surface. A density gradient may be provided. There is also a method in which a fiber web deposited on a net conveyor by composite melt-blow spinning is once wound up, wound up on a core while heating the fiber web again, and then cooled, and the core is removed. In this case, it is not necessary to provide a suction device in the core. In this case as well, the fiber diameter can be changed or a density gradient can be provided in the same manner as described above. The cross section of the core may be elliptical, triangular, quadrangular, or more polygonal in addition to circular, but circular is common. In the present invention, the heat treatment of the fiber web is
This refers to heating at a temperature not lower than the melting point of the low melting point component and not higher than the melting point of the high melting point component of the conjugate fiber to melt only the low melting point component and adhere the fiber contacts to form a three-dimensional structure in the fiber web. As a heat source for the heat treatment, heating with hot air, superheated steam or far-infrared light, a hot embossing method, a heat calendering method, an ultrasonic bonding method, or the like can be used.
In particular, the far-infrared heating method is a preferable method capable of performing uniform heat bonding without disturbing the web obtained by the composite melt blowing method and having a small thickness unevenness, and obtaining a filter having stable filtration performance. As a specific procedure of the heat treatment, there is a method of winding the fiber web around the core while heating, or a method of heating after winding the fiber web around the core,
There is no particular limitation. By such heat treatment, a three-dimensional structure is formed in the fibrous web, and the pore structure in the filter does not become open even when the water pressure fluctuates, and prevents clogging of voids due to fluid pressure. Therefore, excellent pressure resistance is exhibited without using a porous support or a reinforcing material inside the filter layer, and the filtration accuracy is stabilized.
【０００７】[0007]
【実施例】次に本発明を実施例で更に具体的に説明す
る。なお、実施例中に於ける測定法は以下の方法で行っ
た。 ［濾過ライフ］ハウジングに、フィルタ−１本をとりつ
け、３０リットルの水槽からポンプで循環通水する。流
量を３０毎分３０リットルに設定した後、水槽に火山灰
土壌下層土粉末（平均粒径１２．９μｍ、粒径範囲１．
０〜３０μｍが９９％）２０ｇを添加攪拌して循環濾過
を続け、水槽内の液が透明になった時点でフィルタ−入
口圧と出口圧を読む。この操作を入口圧と出口圧の差が
４ｋｇ／ｃｍ2 になるまで続け、それまでの時間（分）
を濾過ライフとした。 ［濾過精度］ハウジングに、フィルター１本を取り付
け、３０リットルの水槽からポンプで循環通水する。流
量を毎分３０リットルに調整した後、水槽にケ−キ（カ
ーボランダム、＃４０００）を５ｇ添加する。ケ−キ添
加より１分後に採取した濾過水１００ミリリットルをメ
ンブレンフィルター（１μｍ以上の粒子を捕集できるも
の）で濾過し、メンブレンフィルター上に捕集されたケ
−キの粒度を、粒径毎の個数を測る粒度分布測定機で測
定し、最大流出粒径を濾過精度とした。 ［平均繊維径］ウェブより５箇所採取した試料に付き各
１枚の電顕写真を撮り、それぞれの写真から任意に２０
本の繊維径を計測し、計１００本の平均繊維径を求め
た。フィルター内部についても同様な方法で平均繊維径
を求めた。Next, the present invention will be described more specifically with reference to examples. In addition, the measuring method in the Example was performed by the following method. [Filtration life] One filter is attached to the housing, and water is circulated through a 30-liter water tank by a pump. After setting the flow rate to 30 liters per minute, the lower layer powder of volcanic ash soil (average particle size 12.9 μm, particle size range 1.
20 g (0 to 30 μm is 99%) is added and stirred to continue the circulation filtration. When the liquid in the water tank becomes transparent, the filter inlet pressure and outlet pressure are read. This operation is continued until the difference between the inlet pressure and the outlet pressure becomes 4 kg / cm 2 , and the time (min) up to that time
Was defined as the filtration life. [Filtration accuracy] One filter is attached to the housing, and water is circulated from a 30-liter water tank by a pump. After adjusting the flow rate to 30 liters per minute, 5 g of cake (Carborundum, # 4000) is added to the water tank. One minute after the addition of the cake, 100 ml of filtered water collected was filtered through a membrane filter (capable of collecting particles of 1 μm or more), and the particle size of the cake collected on the membrane filter was measured for each particle size. Was measured with a particle size distribution analyzer for measuring the number of particles, and the maximum outflow particle size was regarded as filtration accuracy. [Average fiber diameter] One electron micrograph was taken of each sample taken from five places from the web, and 20 photographs were taken from each photograph.
The fiber diameter of each fiber was measured, and the average fiber diameter of a total of 100 fibers was determined. The average fiber diameter of the inside of the filter was determined in the same manner.
【０００８】実施例１ メルトフローレート（以下ＭＦＲと略記する）が８０
（ｇ／１０分、ａｔ２３０℃）、融点１６５℃のポリプ
ロピレンを孔径０．３ｍｍ、孔数５０１のメルトブロ−
用口金を用い、紡糸温度を２８０℃、総吐出量１２０ｇ
／分の条件で紡糸した。紡糸中、温度３５０℃の空気を
圧力１．２ｋｇ／ｃｍ2・Ｇで導入し口金から４８ｃｍ
の距離に設置した吸引装置付きのコンベアネット上に吹
き付け、極細繊維ウェブを得た。得られた繊維ウェブの
平均繊維径は、２．５μｍ、目付４５．０ｇ／ｍ2であ
った。この繊維ウェブを一旦巻取った後、改めて速度１
５ｍ／分のコンベアで送りながら、外径３０ｍｍ、長さ
２５０ｍｍの多孔性プラスチック製中芯に外径６０ｍｍ
になるまで巻き取り、表面の平滑な筒状フィルターを得
た。この筒状フィルターの表面を、縦横高さがいずれも
５ｍｍの四角錐状突起を多数有した金型で、温度１７５
℃、２ｋｇ／ｃｍ2、６０秒間型付け加工し、外周面に
約１２，７００個／ｍ2の凹部を有するフィルターを得
た。このフィルターの濾過面積は型付け前のフィルター
の約１．４倍に当たる６６０ｃｍ2であった。また濾過
性能を測定したところ、濾過精度は３．０μｍで、濾過
ライフは型付け前のフィルターが７分だったのに対し、
型付け後のフィルターは１０分と良好なものであった。Example 1 Melt flow rate (hereinafter abbreviated as MFR) is 80
(G / 10 min, at 230 ° C.), melt-blowing polypropylene having a melting point of 165 ° C. and a pore diameter of 0.3 mm and a pore number of 501.
Using a spinneret, the spinning temperature is 280 ° C and the total discharge amount is 120g
/ Min. During spinning, air at a temperature of 350 ° C. was introduced at a pressure of 1.2 kg / cm 2 · G, and 48 cm from the spinneret.
Was sprayed onto a conveyor net equipped with a suction device installed at a distance of 1 mm to obtain an ultrafine fiber web. The resulting fiber web had an average fiber diameter of 2.5 μm and a basis weight of 45.0 g / m 2 . After winding this fiber web once, speed 1
While feeding on a conveyor of 5 m / min, an outer diameter of 60 mm is attached to a porous plastic core having an outer diameter of 30 mm and a length of 250 mm.
To obtain a cylindrical filter having a smooth surface. The surface of this cylindrical filter was molded with a mold having a large number of quadrangular pyramid-shaped protrusions each having a height and width of 5 mm at a temperature of 175.
° C., then typed processed 2 kg / cm 2, 60 seconds, to obtain a filter having a recess of approximately 12,700 pieces / m 2 on the outer peripheral surface. The filtration area of this filter was 660 cm 2 , which was about 1.4 times that of the filter before molding. When the filtration performance was measured, the filtration accuracy was 3.0 μm, and the filtration life was 7 minutes for the filter before molding,
The filter after the molding was as good as 10 minutes.
【０００９】〔実施例 ２〕ＭＦＲが８０（ｇ／１０
分、ａｔ２３０℃）、融点１６５℃のポリプロピレンを
芯成分とし、ＭＦＲが１２４（ｇ／１０分、ａｔ１９０
℃）、融点１２２℃の線状低密度ポリエチレンを鞘成分
とし、孔径０．３ｍｍ、孔数５０１の芯鞘型メルトブロ
−用口金を用い、芯鞘複合比５０／５０、紡糸温度を芯
成分２８０℃、鞘成分２６０℃、総吐出量１２０ｇ／分
の条件で紡糸した。紡糸中、温度３５０℃の空気を圧力
１．２ｋｇ／ｃｍ2・Ｇで導入し、口金から４８ｃｍの
距離に設置した吸引装置付きのコンベアネット上に吹き
付け、極細の複合繊維ウェブを得た。得られた繊維ウェ
ブの平均繊維径は２．６μｍ、目付４９．０ｇ／ｍ2で
あった。この繊維ウェブを電顕観察したところ、やや繊
維間の融着は観られたものの、ローピングやショットの
ない良好なものであった。この繊維ウェブを一旦巻取っ
た後、改めて速度１５ｍ／分のコンベアで送りながら、
遠赤外ヒータ付き加熱成型装置で雰囲気温度１４０℃の
条件に加熱し、引続き外径３０ｍｍの金属製中芯に外径
が６０ｍｍになるまで巻取り、室温で放冷した後中芯を
抜き取って切断し、外径６０ｍｍ、内径３０ｍｍ、長さ
２５０ｍｍの表面が平滑な筒状フィルターを得た。この
フィルターは、繊維の接点が低融点成分のポリエチレン
の融着により互いに接着されて三次元構造を形成してい
た。この筒状フィルターの表面を、ロールの軸方向と直
角に多数の平行な山脈状突起を有する型付けロールで型
付け加工し、谷の開口幅５ｍｍ、谷の深さ５ｍｍ、山の
尾根幅２．５ｍｍ のＶ字形溝３３本を有するフィルタ
ーを得た。このフィルターの内部の平均繊維径は２．６
μｍで、濾過面積は型付け前のフィルターの約１．７倍
に当たる７００ｃｍ2であった。また濾過性能を測定し
たところ、濾過精度は２．５μｍで、濾過ライフは型付
け前のフィルターが１０分だったのに対し、型付け後の
フィルターは１５分と良好なものであった。Example 2 MFR is 80 (g / 10
Min, at 230 ° C.), polypropylene having a melting point of 165 ° C. as a core component, and MFR of 124 (g / 10 minutes, at 190
C), a core low melting point 122 ° C. linear low-density polyethylene as a sheath component, a core-sheath type melt blower die having a pore diameter of 0.3 mm and a number of pores of 501, and a core-sheath composite ratio of 50/50 and a spinning temperature of 280 core component. The spinning was performed under the conditions of ° C, a sheath component of 260 ° C, and a total discharge amount of 120 g / min. During spinning, air at a temperature of 350 ° C. was introduced at a pressure of 1.2 kg / cm 2 · G and sprayed onto a conveyor net with a suction device installed at a distance of 48 cm from the die to obtain an ultrafine composite fiber web. The average fiber diameter of the obtained fiber web was 2.6 μm, and the weight per unit area was 49.0 g / m 2 . When the fiber web was observed with an electron microscope, fusion between the fibers was slightly observed, but the fiber web was good without roping or shot. After winding this fiber web once, while feeding it again by a conveyor at a speed of 15 m / min,
Heat to a temperature of 140 ° C using a heating and molding device with a far-infrared heater. Then, wind up the metal core with an outer diameter of 30 mm until the outer diameter becomes 60 mm, allow it to cool at room temperature, and then remove the core. It was cut to obtain a cylindrical filter having an outer diameter of 60 mm, an inner diameter of 30 mm, and a length of 250 mm and having a smooth surface. In this filter, the contact points of the fibers were bonded to each other by fusing polyethylene having a low melting point component to form a three-dimensional structure. The surface of the cylindrical filter is formed by molding with a molding roll having a number of parallel mountain-shaped projections perpendicular to the axial direction of the roll, and the valley opening width is 5 mm, the valley depth is 5 mm, and the ridge width is 2.5 mm. A filter having 33 V-shaped grooves was obtained. The average fiber diameter inside this filter is 2.6
In μm, the filtration area was 700 cm 2 , about 1.7 times the size of the unmolded filter. In addition, when the filtration performance was measured, the filtration accuracy was 2.5 μm, and the filtration life was as good as 15 minutes for the filter before molding, while the filter for the filter before molding was 10 minutes.
【００１０】実施例 ３ 固有粘度０．６１、融点２５２℃のポリエステルと、前
記実施例２で用いたものと同一の線状低密度ポリエチレ
ンとを、孔径０．３ｍｍ、孔数５０１の並列型メルトブ
ロ−用口金を用い、複合比５０／５０、紡糸温度をポリ
エステルを３１０℃、ポリエチレンは２４０℃で、総吐
出量１２０ｇ／分の条件で紡糸した。紡糸中、温度４０
０℃の空気を圧力２．０ｋｇ／ｃｍ2・Ｇで導入し、口
金とコンベアとの距離４４ｃｍで紡糸し、コンベア上に
捕集した。この時の繊維ウェブの平均繊維径は５．７μ
ｍ、目付５１．０ｇ／ｍ2であった。得られ極細繊維ウ
ェブを引き続き遠赤外ヒータ付き加熱成型装置に導入
し、以下実施例２と同様の条件で加熱、巻取り、冷却切
断して、外径６０ｍｍ、内径３０ｍｍ、長さ２５０ｍｍ
の表面が平滑な筒状フィルターを得た。このフィルター
は、繊維の接点が低融点成分の線状低密度ポリエチレン
の融着により互いに接着されて三次元構造を形成してい
た。これを実施例２と同様に、山脈状突起を有したエン
ボスロールで型付け加工し、外周面に３３個／２５ｃｍ
の溝を有したフィルターを得た。このフィルター内部の
平均繊維径は５．５μｍで、濾過面積は型付け前のフィ
ルターの約１．５倍に当たる７００ｃｍ2であった。ま
た濾過性能を測定したところ、濾過精度は４．５μｍ
で、濾過ライフは型付け前のフィルターが１９分だった
のに対し、型付け後のフィルターは３１分と良好なもの
であった。Example 3 A polyester having an intrinsic viscosity of 0.61 and a melting point of 252 ° C. and the same linear low-density polyethylene as used in Example 2 were mixed with a parallel melt blower having a pore size of 0.3 mm and 501 holes. Using a spinneret, spinning was performed at a composite ratio of 50/50, a spinning temperature of 310 ° C. for polyester, and 240 ° C. for polyethylene, at a total discharge rate of 120 g / min. During spinning, temperature 40
Air at 0 ° C. was introduced at a pressure of 2.0 kg / cm 2 · G, spun at a distance of 44 cm between the die and the conveyor, and collected on the conveyor. At this time, the average fiber diameter of the fiber web was 5.7 μm.
m and a basis weight of 51.0 g / m 2 . The resulting ultrafine fiber web was subsequently introduced into a heating and molding apparatus equipped with a far-infrared heater, and then heated, wound and cooled under the same conditions as in Example 2 to obtain an outer diameter of 60 mm, an inner diameter of 30 mm, and a length of 250 mm.
A cylindrical filter having a smooth surface was obtained. In this filter, the contact points of the fibers were bonded to each other by fusing linear low-density polyethylene having a low melting point component to form a three-dimensional structure. This was molded using an embossing roll having mountain-shaped protrusions in the same manner as in Example 2, and 33 pieces / 25 cm were formed on the outer peripheral surface.
A filter having grooves was obtained. The average fiber diameter inside this filter was 5.5 μm, and the filtration area was 700 cm 2 , which was about 1.5 times that of the filter before molding. When the filtration performance was measured, the filtration accuracy was 4.5 μm.
The filtration life of the filter before the molding was 19 minutes, whereas the filter after the molding was good at 31 minutes.
【００１１】実施例 ４ 複合比を５５／４５とした以外は実施例２と同じ方法で
紡糸した。この時、外径３０ｍｍの多孔性金属製の円形
パイプからなる中芯を周速１０ｍ／分で回転させなが
ら、パイプの中より吸引機構により排気させ、この中芯
に直接複合メルトブローの極細繊維ウェブを吹き付け、
外径６２ｍｍ、内径３０ｍｍの筒状フィルターを得た。
巻取りに際し、遠赤外ヒータを設置してフィルターの周
囲を、雰囲気温度１４０℃で加熱し成形性を良くした。
この結果、繊維ウェブは繊維の接点が低融点成分のみの
融着により接着されて三次元構造を形成していた。得ら
れた筒状フィルターの平均繊維径は２．４μｍであっ
た。室温で放冷後、中芯を抜き取り、長さを２５０ｍｍ
に切断した。次いで、縦横高さがいずれも５ｍｍの四角
錐状突起を多数有した金型で型付け加工し、外周面に約
１９，０００個／ｍ2の凹部を有するフィルターを得
た。このフィルターの濾過面積は型付け前のフィルター
の約１．６倍に当たる７４９ｃｍ2であった。また濾過
性能を測定したところ、濾過精度は２．７μｍで、濾過
ライフは型付け前のフィルターが１２分だったのに対
し、型付け後のフィルターは１８分であった。Example 4 Spinning was carried out in the same manner as in Example 2 except that the composite ratio was 55/45. At this time, a core made of a circular pipe made of a porous metal having an outer diameter of 30 mm is evacuated from the pipe by a suction mechanism while rotating at a peripheral speed of 10 m / min. Spray
A cylindrical filter having an outer diameter of 62 mm and an inner diameter of 30 mm was obtained.
At the time of winding, a far-infrared heater was installed and the periphery of the filter was heated at an ambient temperature of 140 ° C. to improve moldability.
As a result, the fiber web had a three-dimensional structure in which the contact points of the fibers were bonded by fusing only the low melting point component. The average fiber diameter of the obtained cylindrical filter was 2.4 μm. After cooling at room temperature, the core is removed and the length is 250 mm
Cut into pieces. Next, a mold having a large number of quadrangular pyramid-shaped protrusions each having a length and width of 5 mm was molded and processed to obtain a filter having a concave portion of about 19,000 / m 2 on the outer peripheral surface. The filtration area of this filter was 749 cm 2 , which was about 1.6 times that of the filter before molding. Also, when the filtration performance was measured, the filtration accuracy was 2.7 μm, and the filtration life was 18 minutes for the filter before molding, while the filter life was 12 minutes for the filter before molding.
【００１２】〔実施例 ５〕線状低密度ポリエチレンの
代わりに、ＭＦＲが３５（ｇ／１０分、ａｔ２３０
℃）、融点１３８℃のプロピレン・エチレン・ブテン−
１ランダムコーポリマーを用い、紡糸温度３００℃、温
度３３０℃の空気を圧力１．５ｋｇ／ｃｍ2・Ｇで導入
し、コンベアとの距離４０ｃｍとした以外は実施例２と
同じ条件とした。得られた繊維ウェブの平均繊維径は
２．１μｍ、目付４５．０ｇ／ｍ2であった。この繊維
ウェブを電顕観察したところ、やや繊維間の融着は観ら
れたもののローピングやショットのない良好なものであ
った。この繊維ウェブを一旦巻取った後、コンベアを備
えた遠赤外ヒータ付き加熱成型装置に流し、雰囲気温度
１４５℃で加熱溶融した。この結果、繊維ウェブは繊維
の接点が低融点成分のみの融着により接着され、三次元
構造を形成していた。引続き、外周の各辺が１５ｍｍの
正六角形の金属製中芯に巻取り、室温放冷後、中芯を抜
き取って長さ２５０ｍｍに切断して、表面が平滑な筒状
フィルターを成形した。得られた筒状フィルターの外径
は最大のところが６０ｍｍ、最小は５２ｍｍで、概ね円
形に近いものになった。次いで、前記実施例２と同様の
型付けロールで表面を型付け加工し、外周面にＶ字形溝
を有したフィルターを得た。このフィルター内部の平均
繊維径は２．２μｍで、濾過面積は型付け前のフィルタ
ーの約１．５倍に当たる６９０ｃｍ2であった。また濾
過性能を測定したところ、濾過精度は１．９μｍで、濾
過ライフは型付け前のフィルターが８分だったのに対
し、型付け後のフィルターは１４分であった。Example 5 Instead of linear low-density polyethylene, MFR was 35 (g / 10 minutes, at 230
° C), propylene / ethylene / butene with a melting point of 138 ° C
The same conditions as in Example 2 were used except that 1 random copolymer was used, air at a spinning temperature of 300 ° C. and a temperature of 330 ° C. was introduced at a pressure of 1.5 kg / cm 2 · G, and the distance from the conveyor was 40 cm. The obtained fiber web had an average fiber diameter of 2.1 μm and a basis weight of 45.0 g / m 2 . When the fiber web was observed with an electron microscope, fusion between the fibers was slightly observed, but was good without roping or shot. After winding this fiber web once, it was passed through a heating and molding apparatus equipped with a far-infrared heater equipped with a conveyor, and was heated and melted at an ambient temperature of 145 ° C. As a result, the fiber web had a three-dimensional structure in which the contact points of the fibers were bonded by fusion of only the low melting point component. Subsequently, the outer periphery was wound around a metal core having a regular hexagonal shape having a length of 15 mm, and allowed to cool to room temperature. Then, the core was removed and cut into a length of 250 mm to form a cylindrical filter having a smooth surface. The outer diameter of the obtained cylindrical filter was 60 mm at the maximum and 52 mm at the minimum, which was almost circular. Next, the surface was molded using the same molding roll as in Example 2 to obtain a filter having a V-shaped groove on the outer peripheral surface. The average fiber diameter inside this filter was 2.2 μm, and the filtration area was 690 cm 2 , which was about 1.5 times the filter before molding. In addition, when the filtration performance was measured, the filtration accuracy was 1.9 μm, and the filtration life was 8 minutes for the filter before the molding and 14 minutes for the filter after the molding.
【００１３】[0013]
【発明の効果】本発明のフィルターは、外周面に凹凸状
の加工を設けているので、濾過面積が拡大し、濾過ライ
フを長くすることができる。また本発明のフィルター
は、メルトブロー法による極細複合繊維を用い、低融点
成分による接着により繊維に三次元的な構造とすること
により、フィルター層内の細孔構造は水圧変動などでも
目開きせず、高精度な濾過が安定して実施でき、フィル
ターとしての性能を一層向上させることができる。更に
本発明のフィルターは、メルトブロー法による極細繊維
を使用することにより、繊維加工用静電防止剤（油剤）
を用いないため食品分野、精密濾過分野でもフィルター
を使用前に洗浄する必要がなく、衛生的に使用できる。According to the filter of the present invention, the uneven surface is provided on the outer peripheral surface, so that the filtration area can be increased and the filtration life can be extended. In addition, the filter of the present invention uses a very fine conjugate fiber by a melt blow method, and has a three-dimensional structure on the fiber by bonding with a low melting point component, so that the pore structure in the filter layer does not open even when the water pressure fluctuates. In addition, high-precision filtration can be stably performed, and the performance as a filter can be further improved. Furthermore, the filter of the present invention uses an ultrafine fiber prepared by a melt blow method to thereby provide an antistatic agent for fiber processing (oil agent).
Since the filter is not used, the filter does not need to be washed before use in the food field and the microfiltration field, and can be used hygienically.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭51−134470（ＪＰ，Ａ) 特開 平１−297113（ＪＰ，Ａ) 特開 平３−65207（ＪＰ，Ａ) 特開 昭50−23073（ＪＰ，Ａ) 特開 昭63−287517（ＪＰ，Ａ) 特開 平３−119112（ＪＰ，Ａ) 特開 昭55−99315（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B01D 39/00 - 39/20 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-51-134470 (JP, A) JP-A-1-297113 (JP, A) JP-A-3-65207 (JP, A) JP-A 50-134 23073 (JP, A) JP-A-63-287517 (JP, A) JP-A-3-119112 (JP, A) JP-A-55-99315 (JP, A) (58) Fields investigated (Int. 7 , DB name) B01D 39/00-39/20
Claims (6)
体とする筒状フィルタ−であって、該筒状フィルタ−の
外周面が凹凸状に成形され、その外周面積が、外周面が
平滑である筒状フィルタ−の外周面積の１．２倍以上で
あることを特徴する筒状フィルタ−。1. A cylindrical filter mainly composed of a fiber web having an average fiber diameter of 10 μm or less, wherein an outer peripheral surface of the cylindrical filter is formed into an uneven shape, and an outer peripheral area thereof is smooth. A cylindrical filter characterized by being at least 1.2 times the outer peripheral area of a certain cylindrical filter.
分で構成されるメルトブロ−法複合繊維ウェブであり、
繊維同士の接点が複合繊維の低融点成分により融着接合
されている請求項１記載の筒状フィルタ−。2. A melt-blown conjugate fiber web comprising a composite component having a melting point difference of not less than 20 ° C.,
The cylindrical filter according to claim 1, wherein the contact points between the fibers are fusion-bonded by a low melting point component of the composite fiber.
ェブを中芯に巻き取ってフィルタ−とする際に、巻き取
り時及び／または巻き取り後に凸状型部材で押圧して、
その外周面積を、押圧前の筒状フィルタ−の外周面積の
１．２倍以上にすることを特徴とする筒状フィルタ−の
製造方法。3. When the fiber web obtained by the melt-blowing spinning is wound around a core to form a filter, the fiber web is pressed with a convex member at the time of winding and / or after winding.
A method for manufacturing a cylindrical filter, wherein the outer peripheral area is at least 1.2 times the outer peripheral area of the cylindrical filter before pressing.
筒状フィルタ−の製造方法。4. The method according to claim 3, wherein the convex member is a roll.
分で構成されるメルトブロ−法複合繊維ウェブである請
求項３記載の筒状フィルタ−の製造方法。5. The method for producing a tubular filter according to claim 3, wherein the fiber web is a melt-blown composite fiber web composed of composite components having a melting point difference of 20 ° C. or more.
は巻き取り後に、複合繊維の低融点成分の融点以上で高
融点成分の融点以下の温度で熱処理し、ついで、凸状型
部材で押圧することを特徴とする請求項３記載の筒状フ
ィルタ−の製造方法。6. A heat treatment at a temperature not lower than the melting point of the low melting point component and not higher than the melting point of the high melting point component of the composite fiber when and / or after winding the fibrous web around the core. The method for producing a cylindrical filter according to claim 3, wherein the pressing is performed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5756192A JP3309320B2 (en) | 1992-02-10 | 1992-02-10 | Filter and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5756192A JP3309320B2 (en) | 1992-02-10 | 1992-02-10 | Filter and manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05220312A JPH05220312A (en) | 1993-08-31 |
| JP3309320B2 true JP3309320B2 (en) | 2002-07-29 |
Family
ID=13059245
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5756192A Expired - Fee Related JP3309320B2 (en) | 1992-02-10 | 1992-02-10 | Filter and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3309320B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5607766A (en) * | 1993-03-30 | 1997-03-04 | American Filtrona Corporation | Polyethylene terephthalate sheath/thermoplastic polymer core bicomponent fibers, method of making same and products formed therefrom |
| JP4519674B2 (en) * | 2005-02-18 | 2010-08-04 | 日本バイリーン株式会社 | Filter material and cylindrical filter using the same |
| JP5600106B2 (en) * | 2009-08-10 | 2014-10-01 | 旭化成せんい株式会社 | Filter cloth for dust collector |
-
1992
- 1992-02-10 JP JP5756192A patent/JP3309320B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05220312A (en) | 1993-08-31 |
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