JPH05295645A - Nonwoven fabric and its production - Google Patents
Nonwoven fabric and its productionInfo
- Publication number
- JPH05295645A JPH05295645A JP9794592A JP9794592A JPH05295645A JP H05295645 A JPH05295645 A JP H05295645A JP 9794592 A JP9794592 A JP 9794592A JP 9794592 A JP9794592 A JP 9794592A JP H05295645 A JPH05295645 A JP H05295645A
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- nonwoven fabric
- nozzle
- woven fabric
- average
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、極細繊維よりなる不織
布に関し、更に詳しくは液体フィルターなどに好適に利
用される不織布及びその製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-woven fabric made of ultrafine fibers, and more particularly to a non-woven fabric preferably used for liquid filters and the like and a method for producing the same.
【０００２】[0002]
【従来の技術】極細繊維不織布としては、メルトブロー
法（特開昭４９−１０２５８号公報、特開昭４９−４８
９２１号公報、特開昭５０−１２３１５７号公報参照）
により作られた平均繊維径が０．１μｍ〜２０．０μｍ
である極細繊維不織布が知られている。2. Description of the Related Art As an ultrafine fiber nonwoven fabric, a melt blow method (JP-A-49-10258 and JP-A-49-48) is used.
(See Japanese Patent Application Laid-Open No. 921 and Japanese Patent Application Laid-Open No. 50-123157).
The average fiber diameter made by 0.1μm to 20.0μm
An ultrafine fiber nonwoven fabric is known.
【０００３】[0003]
【発明が解決しようとする課題】これらのメルトブロー
法により得られる不織布は、シート中にロープと呼ばれ
る複数本の繊維が絡み合ってできる束状繊維を多く含ん
でおり、このロープが存在するとフィルターとしての性
能を充分向上させることが難しく、厳しい精度を要求さ
れる膜素材などの用途に対しては著しく信頼性が劣ると
いう問題があった。Nonwoven fabrics obtained by these melt-blowing methods contain a lot of bundled fibers called a rope formed by intertwining a plurality of fibers in a sheet. It is difficult to sufficiently improve the performance, and there is a problem that the reliability is remarkably inferior for applications such as membrane materials that require strict accuracy.
【０００４】かかる問題を解決するためにエアー風量を
大きくし、吐出量を小さくしてコールドプレスする方法
が提案されている（米国特許第４９２５６０１号明細書
参照）。しかしながら、この方法によってもサブミクロ
ン粒子を気相濾過精度及び液相濾過精度良く濾過するこ
とは、充填率が低く、通気抵抗が適切でなく、不十分で
あった。In order to solve such a problem, there has been proposed a method of increasing the air flow rate and reducing the discharge rate to perform cold pressing (see US Pat. No. 4,925,601). However, even by this method, it was insufficient to filter submicron particles with high gas phase filtration accuracy and liquid phase filtration accuracy, because the filling rate was low and the ventilation resistance was not appropriate.
【０００５】そこで、本発明は、充填率、通気抵抗、ポ
アーサイズなどに工夫を加え、フィルターに好適な不織
布およびその製造方法を提供することを課題とするもの
である。Therefore, an object of the present invention is to provide a non-woven fabric suitable for a filter and a method for producing the non-woven fabric, by devising the filling rate, ventilation resistance, pore size and the like.
【０００６】[0006]
【課題を解決するための手段】本発明は、かかる課題を
解決するために次の手段をとるものである。すなわち、
本発明は、平均繊維径が０．５μｍ以上７μｍ以下の極
細繊維からなり、充填率が８％〜２０％の不織布であっ
て、該不織布の幅方向の目付４０ｇ／ｍ2 当りの風速
３．４ｍ／秒での通気抵抗の平均値が１５０ｍｍＡｑ以
上６００ｍｍＡｑ以下であり、前記通気抵抗の最大値と
最小値との差が前記平均値に対して３０％以下であるこ
とを特徴とする不織布、充填率が５５％〜８５％の間に
ある圧着不織布において、最大ポアーサイズが４．０μ
ｍ以下で、且つ平均ポアサイズが２．０μｍ以下であっ
て、該平均ポアサイズに対する該最大ポアーサイズの比
が２．９以下であることを特徴とする圧着不織布、メル
トブロー法により、メルトインデックスが２５０〜１０
００のポリプロピレンの溶融ポリマーをノズルから紡出
し、ゲージ圧で０．２ｋｇ／ｃｍ2 〜０．９８ｋｇ／ｃ
ｍ2 の高速エアー流で牽引細化させて捕集板に引き取っ
て不織布にする際に、前記ノズルのオリアフィスカ径を
０．１ｍｍ以上０．５ｍｍ以下にし、該ノズルの孔の中
心間ピッチを０．５ｍｍ以上２．０ｍｍ以下にし、単孔
当りの吐出量を０．０５ｇ／分〜０．８ｇ／分にし、前
記ノズルと前記捕集板との距離を５ｃｍ〜４０ｃｍにす
ることを特徴とする不織布の製造方法である。The present invention takes the following means in order to solve the above problems. That is,
The present invention is a nonwoven fabric composed of ultrafine fibers having an average fiber diameter of 0.5 μm or more and 7 μm or less and a filling rate of 8% to 20%, and a wind speed of 40 g / m 2 per unit weight in the width direction of the nonwoven fabric. An average value of the ventilation resistance at 4 m / sec is 150 mmAq or more and 600 mmAq or less, and the difference between the maximum value and the minimum value of the ventilation resistance is 30% or less with respect to the average value. In the pressure-bonded non-woven fabric having a ratio of 55% to 85%, the maximum pore size is 4.0μ.
m or less, the average pore size is 2.0 μm or less, and the ratio of the maximum pore size to the average pore size is 2.9 or less, and the melt index is 250 to 10 by the melt blow method.
A polypropylene melt polymer of No. 00 was spun out from a nozzle and the gauge pressure was 0.2 kg / cm 2 to 0.98 kg / c.
When the nonwoven fabric is drawn by a high-speed air flow of m 2 and drawn into a collection plate to form a nonwoven fabric, the diameter of the orifice of the nozzle is set to 0.1 mm or more and 0.5 mm or less, and the center-to-center pitch of the nozzle holes is set to 0. 0.5 mm or more and 2.0 mm or less, the discharge amount per single hole is 0.05 g / min to 0.8 g / min, and the distance between the nozzle and the collecting plate is 5 cm to 40 cm. It is a method for manufacturing a non-woven fabric.
【０００７】以下、本発明を詳細に説明する。まず、本
発明の不織布を構成する材質としては、メルトブロー法
の適用できるものであれば、有機物、無機物またはこれ
らの混合物が挙げられる。代表的な有機物としては、ポ
リオレフィンやポリエステル、ポリアミドなどが、挙げ
られる。また、無機物としては、ガラスや石英質の材質
が挙げられる。このなかで、生産性が良い点からオレフ
ィン系のポリマーが好ましく、特にポリプロピレンのポ
リマーが好ましい。また、ポリエステル系のポリマーで
は液体フィルターとして用いた際に、濾材自身からの抽
出物が少ないため、食料品関係を中心に好ましい。The present invention will be described in detail below. First, examples of the material forming the nonwoven fabric of the present invention include organic substances, inorganic substances, and mixtures thereof as long as the melt blow method can be applied. Typical organic substances include polyolefin, polyester, polyamide and the like. Further, examples of the inorganic material include glass and quartz materials. Among these, an olefin polymer is preferable from the viewpoint of good productivity, and a polypropylene polymer is particularly preferable. In addition, a polyester-based polymer is preferable mainly for food products, since it has a small amount of extractable substance from the filter medium itself when used as a liquid filter.
【０００８】これらの材質により形成される極細繊維の
平均繊維径は、０．５μｍ〜７μｍ好ましくは０．５μ
ｍ〜３μｍである。平均繊維径が７μｍをこえると、微
小な粒子の高い捕集効率を得ることが難しくなる。他
方、０．５μｍより細くなると、不織布のハンドリング
が悪くなるだけでなく、濾過抵抗が高すぎて問題とな
る。The ultrafine fibers formed of these materials have an average fiber diameter of 0.5 μm to 7 μm, preferably 0.5 μm.
It is m-3 micrometers. If the average fiber diameter exceeds 7 μm, it becomes difficult to obtain a high collection efficiency for fine particles. On the other hand, if it is thinner than 0.5 μm, not only the handling of the non-woven fabric is deteriorated, but also filtration resistance is too high, which causes a problem.
【０００９】また、メルトブロー法によって得られる繊
維の繊維径は、ばらつきが大きく、そのため太い繊維が
存在し、濾過効率が低下する。したがって、繊維径の標
準偏差を平均値で割ったＣＶ％が５５％より大きくなる
と濾過性能が低下するので、ＣＶ％は５５％以下が好ま
しく、さらに好ましくは４０％以下、特に好ましくは３
０％以下である。原因については、ＣＶ％が５５％をこ
えると太い繊維が存在するために太い繊維の近傍でチャ
ンネリングが起こるためと推定される。また、不織布を
カレンダー加工して用いる際にプレス加工の抵抗となる
ため安定した充填率調整が難しくなる。Further, the fiber diameter of the fibers obtained by the melt-blowing method has a large variation, so that there are thick fibers and the filtration efficiency decreases. Therefore, if the CV% obtained by dividing the standard deviation of the fiber diameter by the average value is larger than 55%, the filtration performance is deteriorated. Therefore, the CV% is preferably 55% or less, more preferably 40% or less, and particularly preferably 3%.
It is 0% or less. The cause is presumed to be that channeling occurs near thick fibers when CV% exceeds 55% because thick fibers are present. In addition, when the non-woven fabric is used after being calendered, it becomes a resistance to press working, which makes it difficult to stably adjust the filling rate.
【００１０】不織布の風速３．４ｍ／秒の通気抵抗は、
目付４０ｇ／ｍ2 当り１５０ｍｍＡｑ以上６００ｍｍＡ
ｑ以下、好ましくは２５０ｍｍＡｑ以上５００ｍｍＡ
ｑ、さらに好ましくは３００ｍｍＡｑ以上４８０ｍｍＡ
ｑ以下である。通気抵抗の最適値は繊維径が小さいほど
その値が大きくなる。目付が４０ｇ／ｍ2 でない場合に
は、その目付での通気抵抗を以下の式により計算して、
４０ｇ／ｍ2 当りに換算する。４０ｇ／ｍ2 目付当り通
気抵抗（ｍｍＡｑ）＝実目付の通気抵抗（ｍｍＡｑ）×
４０（ｇ／ｍ2 ）／実目付（ｇ／ｍ2 ）・・・・・・・・（Ｉ）The ventilation resistance of the nonwoven fabric at a wind speed of 3.4 m / sec is
Basis weight 40g / m 2 150mmAq or more 600mmA
q or less, preferably 250 mmAq or more and 500 mmA
q, more preferably 300 mmAq or more and 480 mmA
It is less than or equal to q. The optimum value of ventilation resistance increases as the fiber diameter decreases. If the basis weight is not 40 g / m 2 , calculate the ventilation resistance at that basis by the following formula,
Convert to 40 g / m 2 . 40 g / m 2 Air flow resistance per unit weight (mmAq) = Air resistance with actual weight (mmAq) ×
40 (g / m 2 ) / actual basis weight (g / m 2 ) ... (I)
【００１１】通気抵抗は、目付当りに換算すると、充填
率（％）に依存するが、本発明領域での充填率でこの通
気抵抗の範囲にあることが好ましい。また、通気抵抗の
ばらつきが小さいことが、フィルター性能の安定化につ
ながる。この通気抵抗は、不織布の幅方向に１インチ間
隔で直径１インチの円盤形の不織布部分を風速３４０ｃ
ｍ／秒で測定した目付４０ｇ／ｍ2 当りの値であるが、
この通気抵抗の最大値と最小値との差が平均の通気抵抗
に対して３０％以下、好ましくは２５％以下である。The air flow resistance, when converted into a basis weight, depends on the filling rate (%), but it is preferable that the air flow resistance is within the range of the air flow resistance in the range of the present invention. In addition, a small variation in ventilation resistance leads to stabilization of filter performance. This ventilation resistance is measured at a wind speed of 340c at a disc-shaped non-woven fabric portion having a diameter of 1 inch at intervals of 1 inch in the width direction of the non-woven fabric.
It is a value per unit weight of 40 g / m 2 measured at m / sec.
The difference between the maximum value and the minimum value of the airflow resistance is 30% or less, preferably 25% or less with respect to the average airflow resistance.
【００１２】従来においては、繊維の分散性が悪く、繊
維本数の粗密が存在することにより通気抵抗のばらつき
が大きく、通気抵抗の最大値と最小値との差が平均の通
気抵抗に対して３０％をこえる場合が少なくないという
問題があった。これに対して本発明においては、繊維の
分散性を良くして、通気抵抗の平均値を所定範囲におさ
めるとともに、気相系のエアフィルターとして不織布を
用いる際の充填率は８％〜２０％におさめるようにした
ものである。充填率が低すぎると濾過効率が低下し、他
方、充填率が高すぎると気相での濾過抵抗が高く、用途
が著しく制限される。Conventionally, the dispersibility of the fibers is poor, and the unevenness of the number of fibers causes a large variation in the ventilation resistance, and the difference between the maximum value and the minimum value of the ventilation resistance is 30 with respect to the average ventilation resistance. There was a problem that it often exceeded%. On the other hand, in the present invention, the dispersibility of the fibers is improved to keep the average value of the ventilation resistance within a predetermined range, and the filling rate when using a nonwoven fabric as a gas phase air filter is 8% to 20%. It was designed to be stored in. If the filling rate is too low, the filtration efficiency will decrease, while if the filling rate is too high, the filtration resistance in the gas phase will be high, and the applications will be significantly limited.
【００１３】本発明においては通気抵抗は、繊維の粗密
を反映するように、不織布の幅方向に１インチ間隔で直
径１インチの円盤形の部分を風速３４０ｃｍ／秒で測定
し、目付４０ｇ／ｍ2 当りに換算した値を用いる。本測
定で測定を１インチにしたのは、小さな部位での繊維の
分散性をより正確に評価するためである。In the present invention, the ventilation resistance is measured at a wind velocity of 340 cm / sec for a disc-shaped portion having a diameter of 1 inch at intervals of 1 inch in the width direction of the non-woven fabric so as to reflect the density of the fibers, and a basis weight of 40 g / m 2. The value converted per 2 is used. The reason why the measurement is 1 inch in this measurement is to more accurately evaluate the dispersibility of the fiber in a small area.
【００１４】また、本発明の圧着不織布は、カレンダー
処理等をして、液体フィルター用として好適に用いられ
るものであるが、充填率５５％〜８５％の間にあること
が好ましい。充填率５５％より小さいと、液相濾過精度
が上がらなくなる。また、カレンダー処理した不織布に
シワ等が入ったり、プリーツ加工などの後加工を行う際
に、部分的に充填率が変化するという問題が生じる。他
方、８５％を超えると濾過抵抗が大きくなりすぎて使用
に問題がある。また、通常充填率が上がると濾過精度は
向上するが、充填率が７５％より高くなった所から、濾
過抵抗が上昇する割には濾過精度が向上しないことが明
らかとなった。この原因として、充填率が８５％をこえ
ると繊維により形成されるポアーが遺れすぎて閉塞する
個所が増加するためと考えられる。The pressure-bonded non-woven fabric of the present invention is preferably used for a liquid filter after being subjected to calendering or the like, but the filling rate is preferably between 55% and 85%. When the filling rate is less than 55%, the liquid phase filtration accuracy cannot be improved. In addition, when the calendered nonwoven fabric has wrinkles or the like, or when post-processing such as pleating is performed, there is a problem that the filling rate partially changes. On the other hand, if it exceeds 85%, the filtration resistance becomes too large and there is a problem in use. Moreover, although the filtration accuracy is improved when the normal filling rate is increased, it is clear that the filtration accuracy is not improved even though the filtration resistance is increased since the filling rate is higher than 75%. It is considered that the reason for this is that when the filling rate exceeds 85%, the pores formed by the fibers are left behind too much and the number of points to be blocked increases.
【００１５】前記の圧着不織布は、毛細管吸引力を測定
するポロメーター（コールタール社）により測定した平
均ポアーサイズが２．０μｍ以下でなければならない。
これは、最大ポアーサイズの大きさと相俟って液相濾過
精度を上げるためである。また、最大ポアーサイズは
４．０μｍ以下、好ましくは３．０μｍ以下である。通
液抵抗を上げずに平均ポアーサイズの大きさと相俟って
液相濾過精度を上げるためである。The pressure-bonded non-woven fabric should have an average pore size of 2.0 μm or less as measured by a porometer (Coal Tar Co., Ltd.) for measuring capillary suction force.
This is to improve the liquid phase filtration accuracy in combination with the maximum pore size. The maximum pore size is 4.0 μm or less, preferably 3.0 μm or less. This is because the liquid phase filtration accuracy is improved in combination with the average pore size without increasing the liquid passage resistance.
【００１６】次に、最大ポアーサイズと平均ポアーサイ
ズとの比（以下「ポアーインデックス」という。）が
２．９以下であることが必要である。このポアーインデ
ックスが小さいことは、不織布又は圧着不織布のポアー
サイズが均一であることを示し、ポアーインデックスが
小さいほど同じ濾過精度で通気抵抗又は通液抵抗を小さ
くすることを示す目安となるものである。通常の濾過で
は最大ポアーサイズが濾過の精度を支配的に決定するこ
とから、同一充填率では濾過精度が高く、他方、同一濾
過精度では濾過抵抗を小さくすることができる。また、
濾材の目付を小さくしても、濾過精度の大きな低下がな
いことにも関連する。すなわち、本発明の圧着不織布
は、濾過精度と濾過抵抗のバランスに優れた濾材として
好適に使用される。Next, it is necessary that the ratio between the maximum pore size and the average pore size (hereinafter referred to as "pore index") is 2.9 or less. The small pore index indicates that the non-woven fabric or the pressure-bonded non-woven fabric has a uniform pore size, and the smaller the pore index, the smaller the porosity index becomes, which is a standard for indicating that the ventilation resistance or the liquid passage resistance is reduced with the same filtration accuracy. In normal filtration, the maximum pore size determines the accuracy of filtration predominantly, so that filtration accuracy is high at the same filling rate, and filtration resistance can be reduced at the same filtration accuracy. Also,
It is also related to the fact that even if the basis weight of the filter material is reduced, the filtration accuracy does not decrease significantly. That is, the pressure-bonded non-woven fabric of the present invention is suitably used as a filter medium having an excellent balance between filtration accuracy and filtration resistance.
【００１７】本発明の圧着不織布は、構成繊維がすでに
述べたような平均繊維径が０．５μｍ〜７μｍの極細繊
維からなるものが好ましく、また、その繊維径のＣＶ％
が５５％以下であることが好ましい。The pressure-bonded non-woven fabric of the present invention is preferably composed of ultrafine fibers having an average fiber diameter of 0.5 μm to 7 μm as the constituent fibers, and the CV% of the fiber diameter.
Is preferably 55% or less.
【００１８】本発明の不織布をエアーフィルターとして
用いる際には荷電処理を実施することによりいわゆるエ
レクトレット化を実施することが好ましい。When the nonwoven fabric of the present invention is used as an air filter, it is preferable to carry out so-called electretization by carrying out a charging treatment.
【００１９】液体フィルターとして本発明の充填率が８
〜２０％の不織布を用いる際には、不織布を積層して用
いることが好ましい。不織布一枚でのサブミクロン粒子
の濾過を実施する際には濾過効率を上げることが難しく
なる。従って、少なくとも５層、好ましくは１０層以
上、更に好ましくは１４層以上積層することが好まし
い。不織布を積層する効果は粒子が多分散である場合や
粒子が完全に固体でない場合に効果を特に発揮する。粒
子が多分散であるというのは、単分散ポリスチレンラテ
ックスなどのように粒子径がそろっておらず、ここでは
粒子径の標準偏差が平均粒子径の５〜１０％より大きい
場合をさし、また、粒子が完全な固体でないというの
は、粒子が濾過層内で何等かの刺激や応力により変形す
ることをいい、ゲル状物や血液中の血球などをその代表
としてあげられ、積層数をあげて行くと、濾過抵抗が高
まるが、通気抵抗の合計が７０００ｍｍＡｑ以下である
ことが好ましい。１枚当りの通気抵抗の小さいときには
積層効果が大きい。As a liquid filter, the filling factor of the present invention is 8
When using -20% non-woven fabric, it is preferable to use non-woven fabrics laminated. When performing filtration of submicron particles with a single piece of nonwoven fabric, it becomes difficult to increase the filtration efficiency. Therefore, it is preferable to stack at least 5 layers, preferably 10 layers or more, and more preferably 14 layers or more. The effect of laminating the nonwoven fabric is particularly exerted when the particles are polydisperse or when the particles are not completely solid. The particles being polydisperse means that the particles do not have the same particle size as in monodisperse polystyrene latex and the standard deviation of the particle size is larger than 5 to 10% of the average particle size. The fact that the particles are not completely solid means that the particles are deformed by some kind of stimulus or stress in the filtration layer, and gel-like substances and blood cells in blood are representative thereof, and the number of layers is increased. The filtration resistance increases as the temperature rises, but the total ventilation resistance is preferably 7,000 mmAq or less. When the ventilation resistance per sheet is small, the stacking effect is large.
【００２０】他方、カレンダー処理して充填率を５５〜
８５％に調整した不織布は、その積層効果が少なく、多
くても１０層以下、更に好ましくは５層以下であること
が好ましい。これは、不織布の表面での濾過が深さ方向
の濾過に対して寄与するものが大きいことによると考え
られる。また、全体の圧力損失が大きくなりすぎること
も問題である。On the other hand, a filling rate of 55 to 55 is obtained by calendering.
The non-woven fabric adjusted to 85% has little lamination effect, and it is preferable that the number of layers is at most 10 layers, more preferably at most 5 layers. It is considered that this is because the filtration on the surface of the non-woven fabric largely contributes to the filtration in the depth direction. Another problem is that the overall pressure loss becomes too large.
【００２１】また、他のタイプの不織布や織布または多
孔フイルムなど多孔質材料と積層して用いて濾過精度や
ライフの改善を実施することもでき、粒状または繊維状
活性炭などの吸着材と併用して使うことも脱臭や脱イオ
ン、脱溶剤等の観点から望ましい形態である。その他、
繊維をコロナ放電、電子線照射や親水化剤添付などの後
加工により親水化処理をし、初期の濡れ性を改善するこ
とも好ましい。It is also possible to improve the filtration accuracy and life by laminating it with other types of non-woven fabrics, woven fabrics or porous materials such as porous films, and to use it together with adsorbents such as granular or fibrous activated carbon. It is also desirable to use it from the viewpoint of deodorization, deionization, desolvation and the like. Other,
It is also preferable to improve the initial wettability by subjecting the fibers to a hydrophilic treatment by post-processing such as corona discharge, electron beam irradiation or attachment of a hydrophilic agent.
【００２２】次に、本発明の製造方法を説明する。メル
トブロー法により、メルトインデックスが２５０〜１０
００のポリプロピレンの溶融ポリマーをオリフィス径が
０．１ｍｍ〜０．５ｍｍのノズルから紡出する。オリフ
ィス径が０．１ｍｍより小さいと、オリフィスの加工精
度からオリフィス形状が不揃いになり、繊維径のＣＶ％
が大きくなるので好ましくない。また、ポリマーの劣化
などにより長期運転時に孔がつまり易いという問題が生
じるので好ましくない。他方、０．５ｍｍより大きいと
極細繊維を得ることが困難になるので好ましくない。Next, the manufacturing method of the present invention will be described. Melt index of 250-10 by melt blow method
The molten polymer of polypropylene of No. 00 is spun from a nozzle having an orifice diameter of 0.1 mm to 0.5 mm. If the orifice diameter is smaller than 0.1 mm, the orifice shape will be uneven due to the machining accuracy of the orifice, and the CV% of the fiber diameter
Is large, which is not preferable. In addition, there is a problem that pores are likely to be clogged during long-term operation due to deterioration of the polymer, which is not preferable. On the other hand, if it is larger than 0.5 mm, it becomes difficult to obtain ultrafine fibers, which is not preferable.
【００２３】オリフィスの中心孔間の距離は０．５ｍｍ
〜２．０ｍｍ、好ましくは０．７５ｍｍ〜１．５ｍｍさ
らに好ましくは０．８０ｍｍ〜１．２ｍｍである。０．
５ｍｍより小さくなるとロープが発生しやすくなり、濾
過精度が低下する。これは、隣の繊維との接触の確率が
増大し、繊維が絡まってロープが発生しやすくなるため
と考えられる。The distance between the center holes of the orifices is 0.5 mm
˜2.0 mm, preferably 0.75 mm to 1.5 mm, more preferably 0.80 mm to 1.2 mm. 0.
If it is less than 5 mm, ropes are likely to be generated and the filtration accuracy is reduced. It is considered that this is because the probability of contact with the adjacent fiber is increased, and the fibers are entangled with each other and the rope is easily generated.
【００２４】他方、２．０ｍｍをこえると、繊維同志の
交絡がきわめて低下し、不織布の寸法安定性が低下し、
不織布の強力低下や毛羽立ちの問題が生じる。また、単
孔吐出量は０．０５ｇ／分〜０．８ｇ／分、好ましくは
０．１ｇ／分〜０．５ｇ／分である。吐出量が０．０５
ｇ／分より小さくなると生産性が低くなるだけでなく、
フライと呼ばれる繊維の糸切れが発生しやすくなり、連
続操業運転時に孔詰りが生じやすい。他方、０．８ｇ／
分より大きくなると、ショットと呼ばれる玉状の繊維が
発生しやすくなり、また、ポリマーの熱容量が大きいた
め繊維の冷却が遅れ、未固化の繊維がすでに形成された
不織布シートに落ちて、シートに貫通孔が明けられると
いう問題が生じる。On the other hand, when it exceeds 2.0 mm, the entanglement of the fibers is extremely reduced, and the dimensional stability of the non-woven fabric is reduced.
The strength of the non-woven fabric is reduced and fluffing occurs. The single-hole discharge rate is 0.05 g / min to 0.8 g / min, preferably 0.1 g / min to 0.5 g / min. Discharge rate is 0.05
If it is less than g / min, not only will productivity decrease, but
Thread breakage of fibers called fly is likely to occur and clogging is likely to occur during continuous operation. On the other hand, 0.8 g /
If it is larger than that, beaded fibers called shots are likely to be generated, and because the heat capacity of the polymer is large, the cooling of the fibers is delayed, and the unsolidified fibers fall into the already formed nonwoven fabric sheet and penetrate the sheet. The problem arises that the holes are opened.
【００２５】また、ポリプロピレンのポリマーのメルト
インデックスは２５０〜１０００であるが、２５０（ｇ
／１０分）未満になると細化が不充分となって好ましく
なく、１０００（ｇ／１０分）をこえると糸切れが増え
たり、糸径のばらつきが大きくなってあまり好ましくな
い。The melt index of the polypropylene polymer is 250 to 1000, but 250 (g
If it is less than / 10 minutes), the thinning becomes insufficient, which is not preferable, and if it exceeds 1000 (g / 10 minutes), the number of yarn breakages increases and the variation in yarn diameter becomes large, which is not preferable.
【００２６】さらに、高速エアー流はゲージ圧で０．２
ｋｇ／ｃｍ2〜０．９８ｋｇ／ｃｍ2であるが、０．２ｋ
ｇ／ｃｍ2 未満になると、糸条の細化が不充分となり好
ましくない。他方、０．９８ｋｇ／ｃｍ2 をこえると、
牽引エアー速度が超音速流となり、流れの非定常が高く
なり好ましくない。Further, the high-speed air flow is 0.2 in gauge pressure.
is a kg / cm 2 ~0.98kg / cm 2 , 0.2k
If it is less than g / cm 2, thinning of the yarn is insufficient, which is not preferable. On the other hand, if it exceeds 0.98 kg / cm 2 ,
The traction air velocity becomes supersonic flow, and unsteady flow becomes high, which is not preferable.
【００２７】また、ノズルと捕集板との距離は５ｃｍ〜
４０ｃｍである。好ましくは、 ６cm〜３０ｃｍ、さらに
好ましくは７ｃｍ〜２５ｃｍである。５ｃｍより小さく
なると、繊維の冷却遅れにより不織布に貫通孔が生じた
り、牽引流体流の捕集板上での速度が早くなって不織布
の表面を毛羽だたせたりして好ましくない。他方、４０
ｃｍより大きくなると、ロープが増加し繊維の分散性が
著しく低下するので好ましくない。不織布シートの貫通
孔がなく、ロープ状物が小さい不織布をえるためには、
単孔吐出量とオリフィス間ピッチ、牽引流体流量に応じ
てノズルと捕集板との間の距離の最適化を図ることが必
要であると考えられる。なお、ミストクエンチなどの冷
却強化手段を用いると、この距離はさらに短くすること
が可能であり、５〜１０ｃｍの距離が液相フィルターと
して利用する際に特に好ましい。The distance between the nozzle and the collecting plate is 5 cm to
It is 40 cm. It is preferably 6 cm to 30 cm, more preferably 7 cm to 25 cm. If it is less than 5 cm, a through-hole may be formed in the nonwoven fabric due to a delay in cooling of the fibers, or the speed of the traction fluid flow on the collecting plate may be increased to cause the surface of the nonwoven fabric to be fluffed, which is not preferable. On the other hand, 40
If it is larger than cm, the rope is increased and the dispersibility of the fiber is significantly lowered, which is not preferable. In order to obtain a non-woven fabric with a small rope-like material that does not have through holes in the non-woven fabric sheet,
It is considered necessary to optimize the distance between the nozzle and the collecting plate according to the single hole discharge amount, the pitch between the orifices, and the flow rate of the drawing fluid. If a cooling intensifying means such as mist quench is used, this distance can be further shortened, and a distance of 5 to 10 cm is particularly preferable when used as a liquid phase filter.
【００２８】[0028]
実施例１〜１３、比較例１〜１４ メルトブロー法により、ポリプロピレンのポリマーを表
１〜表６に示す条件により同表の不織布（目付４０ｇ／
ｍ2 ）を製造して、その特性を測定した。また、該不織
布を熱プレスローラー（表面温度９０〜１３０℃、圧着
力５０〜１５０ｋｇ／ｃｍ）により圧着して所望の充填
率に調整したものも測定した。気相での濾過効率の測定
に用いる不織布は２０ＫＶで１０秒間エレクトレット処
理を行った。Examples 1 to 13 and Comparative Examples 1 to 14 By the melt blow method, the polypropylene polymer was subjected to the conditions shown in Tables 1 to 6 to obtain the nonwoven fabric of the same table (Basis weight 40 g /
m 2 ) was produced and its properties were measured. Further, the non-woven fabric was also pressure-bonded with a hot press roller (surface temperature 90 to 130 ° C., pressure force 50 to 150 kg / cm) and adjusted to a desired filling rate. The non-woven fabric used for measuring the filtration efficiency in the gas phase was subjected to electret treatment at 20 KV for 10 seconds.
【００２９】なお、測定方法は、次のとおりである。 平均繊維径およびＣＶ％：シートの表面の走査型電
子顕微鏡写真を１０００〜３０００倍の倍率で撮影し、
その写真の繊維径をランダムに２００本測定して、その
算術平均値を平均繊維径（μｍ）とした。 目付（ｇ／ｍ2 ）：２０ｃｍ角のサンプル（ｎ＝
５）の重量を測定し、 １ｍ2 当りに換算した平均値を目
付（ｇ／ｍ2 ）とした。The measuring method is as follows. Average fiber diameter and CV%: A scanning electron micrograph of the surface of the sheet was taken at a magnification of 1000 to 3000 times,
The fiber diameter in the photograph was measured at 200 randomly, and the arithmetic average value was defined as the average fiber diameter (μm). Unit weight (g / m 2 ): 20 cm square sample (n =
The weight of 5) was measured, and the average value converted per 1 m 2 was defined as the basis weight (g / m 2 ).
【００３０】 充填率（％）：シートの厚み（ｍ）を
ＪＩＳ Ｌ−１０９６のダイヤルゲージ法により７ｇ／
ｃｍ2 の荷重下で測定した。シートの目付（ｇ／ｍ2 ）
を厚み（ｍ）で割り、百分率（％）であらわした。 気相濾過精度（％）：０．３μｍの空気塵の捕集効
率を線速度５．３ｃｍ／秒で測定し、｛（入口濃度−出
口濃度）／入口濃度｝×１００で求めた。 通気抵抗（ｍｍＡｑ）：空気の通気抵抗を直径２５
ｍｍの円形サンプルを用いて線速度３．４ｍ／秒で差圧
計により測定した。 通液抵抗（ｍｍＡｑ）：線速度２．２ｃｍ／分のと
きの水の通液抵抗を差圧計により求めた。なお、サンプ
ルの大きさは直径１４０ｃｍの円形部分である。 液相濾過精度（％）：日本合成ゴム社製の０．４３
μｍのポリスチレンラテックスの濾過精度を濾過速度
２．２ｃｍ／分で、｛（入口濃度−出口濃度）／入口濃
度｝×１００により求めた。 最大ポアーサイズ及び平均ポアーサイズ：コールタ
ー社ポロメーターIIにより測定した（ＡＳＴＭＦ３１６
−７０）。Filling ratio (%): The thickness (m) of the sheet is 7 g / m according to the dial gauge method of JIS L-1096.
It was measured under a load of cm 2 . Sheet weight (g / m 2 )
Was divided by the thickness (m) and expressed as a percentage (%). Gas phase filtration accuracy (%): The collection efficiency of 0.3 μm air dust was measured at a linear velocity of 5.3 cm / sec, and determined by {(inlet concentration-outlet concentration) / inlet concentration} × 100. Ventilation resistance (mmAq): The ventilation resistance of air is 25
The measurement was performed with a differential pressure meter at a linear velocity of 3.4 m / sec using a circular sample of mm. Liquid permeation resistance (mmAq): The liquid permeation resistance of water at a linear velocity of 2.2 cm / min was determined by a differential pressure gauge. The size of the sample is a circular portion having a diameter of 140 cm. Liquid phase filtration accuracy (%): 0.43 manufactured by Japan Synthetic Rubber Co., Ltd.
The filtration accuracy of the polystyrene latex of μm was determined by {(inlet concentration−outlet concentration) / inlet concentration} × 100 at a filtration rate of 2.2 cm / min. Maximum Pore Size and Average Pore Size: Measured by Coulter Porometer II (ASTMF316
-70).
【００３１】[0031]
【表１】 [Table 1]
【００３２】[0032]
【表２】 [Table 2]
【００３３】[0033]
【表３】 [Table 3]
【００３４】[0034]
【表４】 [Table 4]
【００３５】[0035]
【表５】 [Table 5]
【００３６】[0036]
【表６】 実施例１〜４と比較例１〜５とから明らかなように、同
一繊維径では気相および液相の濾過精度が実施例の方が
優れている。通気抵抗についてみると、繊維が細い程高
くなるが、充填率が２０％より高くなると通気抵抗が大
きくなりすぎて、気相のフィルターとしての用途が著し
く阻害される。比較例３、５のように繊維径が太くなり
すぎると充填率を高くしても精度は期待できない。[Table 6] As is clear from Examples 1 to 4 and Comparative Examples 1 to 5, with the same fiber diameter, the filtration accuracy of the gas phase and the liquid phase is better in the Example. Regarding air flow resistance, the finer the fiber, the higher the air flow resistance. However, if the filling rate is higher than 20%, the air flow resistance becomes too large, and the use as a gas phase filter is significantly impaired. If the fiber diameter becomes too thick as in Comparative Examples 3 and 5, accuracy cannot be expected even if the filling rate is increased.
【００３７】実施例５〜８、比較例６〜９で明らかな様
に、オリフィス径が大きくなると繊維を細くしにくく、
紡糸応力が低下するためか繊維径のＣＶ％が増加する。
また、オリフィスピッチが小さすぎると、シート中にロ
ープが増え、繊維径ＣＶ％も高くなる。繊維の充填率が
高すぎると、濾過抵抗が大きくフィルターとして好まし
くない。ノズル、捕集間距離は繊維径が太いほど大きく
とる必要があるが、繊維の分散性が悪くなり、通気抵抗
もバラツキが大きく濾過精度も良くない。As is clear from Examples 5 to 8 and Comparative Examples 6 to 9, when the orifice diameter is increased, it is difficult to make the fiber thin,
The CV% of the fiber diameter increases, probably because the spinning stress decreases.
Further, if the orifice pitch is too small, ropes increase in the sheet and the fiber diameter CV% also increases. If the filling rate of the fibers is too high, the filtration resistance is large and it is not preferable as a filter. The larger the fiber diameter is, the larger the distance between the nozzle and the collection needs to be made, but the dispersibility of the fiber is deteriorated, the ventilation resistance varies greatly, and the filtration accuracy is poor.
【００３８】実施例１０〜１３、比較例１１〜１４に示
すものは、圧着不織布の例であるが、比較例１０は充填
率が低く、しかも最大ポアーサイズも平均ポアーサイズ
もポアーインデックスが範囲外であるので液相濾過精度
が悪かった。比較例１４は、特に最大ポアーサイズが特
に大きいため液相濾過精度は特に悪かった。比較例１２
は充填率が高すぎて液相濾過精度は良いものの、通液抵
抗が大きく不充分であった。比較例１３はポアーインデ
ックスが２．９をこえているために通液濾過精度は若干
低く、両者のバランスが不充分であった。The examples shown in Examples 10 to 13 and Comparative Examples 11 to 14 are examples of pressure-bonded non-woven fabrics. In Comparative Example 10, the filling rate is low, and the maximum pore size, average pore size, and pore index are out of the range. Therefore, the liquid phase filtration accuracy was poor. In Comparative Example 14, the maximum pore size was particularly large, so the liquid phase filtration accuracy was particularly poor. Comparative Example 12
The filling rate was too high and the liquid phase filtration accuracy was good, but the liquid resistance was large and insufficient. In Comparative Example 13, the porosity index exceeded 2.9, and therefore the filtration accuracy for liquid passing was slightly low, and the balance between the two was insufficient.
【００３９】[0039]
【発明の効果】本発明により液相および気相の両方で濾
過精度が高く、通気抵抗の小さい優れた濾過性能を示す
濾過材として好適に用いられる不織布を得ることができ
る。また、この不織布はその特性から保温材やセパレー
タ、医療用布としても用いることができる。EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain a non-woven fabric which has a high filtration accuracy in both the liquid phase and the gas phase and has a small ventilation resistance and which is suitably used as a filtration material having excellent filtration performance. Further, this non-woven fabric can be used as a heat insulating material, a separator, and a medical cloth because of its characteristics.
Claims (4)
の極細繊維からなり、充填率が８％〜２０％の不織布で
あって、該不織布の幅方向の目付４０g/ｍ2当りの風速
３．４ｍ／秒での通気抵抗の平均値が１５０ｍｍＡｑ以
上６００ｍｍＡｑ以下であり、前記通気抵抗の最大値と
最小値との差が前記平均値に対して３０％以下であるこ
とを特徴とする不織布。1. A non-woven fabric composed of ultrafine fibers having an average fiber diameter of 0.5 μm or more and 7 μm or less and a filling rate of 8% to 20%, and a wind speed of 3 per 40 g / m 2 of basis weight of the nonwoven fabric. An average value of ventilation resistance at 0.4 m / sec is 150 mmAq or more and 600 mmAq or less, and a difference between the maximum value and the minimum value of the ventilation resistance is 30% or less with respect to the average value.
である請求項１に記載の不織布。2. The non-woven fabric according to claim 1, wherein the CV% of the fiber diameter of the ultrafine fibers is 55% or less.
不織布において、最大ポアーサイズが４．０μｍ以下
で、且つ平均ポアーサイズが２．０μｍ以下であって、
該平均ポアサイズに対する該最大ポアーサイズの比が
２．９以下であることを特徴とする圧着不織布。3. A pressure-bonded non-woven fabric having a filling rate of 55% to 85%, having a maximum pore size of 4.0 μm or less and an average pore size of 2.0 μm or less,
A pressure-bonded non-woven fabric, wherein the ratio of the maximum pore size to the average pore size is 2.9 or less.
スが２５０〜１０００のポリプロピレンの溶融ポリマー
をノズルから紡出し、ゲージ圧で０．２kg／cm2 の高速
エアー流で牽引細化させて捕集板に引き取って不織布に
する際に、前記ノズルのオリフィス径を０．１ｍｍ以上
０．５ｍｍ以下にし、該ノズルの孔の中心間ピッチを
０．５ｍｍ以上２．０ｍｍ以下にし、単孔当りの吐出量
を０．０５ｇ／分〜０．８ｇ／分にし、前記ノズルと前
記捕集板との距離を５ｃｍ〜４０ｃｍにすることを特徴
とする不織布の製造方法。4. A melt polymer of polypropylene having a melt index of 250 to 1000 is spun out from a nozzle by a melt blow method, drawn by a high-speed air flow of 0.2 kg / cm 2 at a gauge pressure and drawn into a collecting plate. When making the nonwoven fabric into a nonwoven fabric, the orifice diameter of the nozzle is set to 0.1 mm or more and 0.5 mm or less, the center-to-center pitch of the nozzle holes is set to 0.5 mm or more and 2.0 mm or less, and the discharge amount per single hole is 0. 0.05 g / min to 0.8 g / min, and the distance between the nozzle and the collecting plate is set to 5 cm to 40 cm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9794592A JP3164172B2 (en) | 1992-04-17 | 1992-04-17 | Nonwoven fabric and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9794592A JP3164172B2 (en) | 1992-04-17 | 1992-04-17 | Nonwoven fabric and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05295645A true JPH05295645A (en) | 1993-11-09 |
| JP3164172B2 JP3164172B2 (en) | 2001-05-08 |
Family
ID=14205814
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9794592A Expired - Fee Related JP3164172B2 (en) | 1992-04-17 | 1992-04-17 | Nonwoven fabric and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3164172B2 (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005098118A1 (en) * | 2004-04-09 | 2005-10-20 | Mitsui Chemicals, Inc. | Nonwoven fabric sheet and method for producing same |
| JP2009095731A (en) * | 2007-10-15 | 2009-05-07 | Kuraray Chem Corp | Filter for water treatment |
| JP2009233550A (en) * | 2008-03-26 | 2009-10-15 | Kuraray Co Ltd | Filter medium for gas filter |
| JP2010125404A (en) * | 2008-11-28 | 2010-06-10 | Mitsui Chemicals Inc | Liquid filter |
| JP2010137121A (en) * | 2008-12-09 | 2010-06-24 | Roki Techno Co Ltd | Filter having high differential pressure-proof performance and gel foreign matter elimination performance |
| US9200392B2 (en) | 2010-12-06 | 2015-12-01 | Mitsui Chemicals, Inc. | Melt-blown nonwoven fabric, and production process and apparatus for the same |
| JP2016053241A (en) * | 2011-01-28 | 2016-04-14 | タピルス株式会社 | Melt blown nonwoven fabric comprising ultrafine fiber and laminated processed product |
| JP2017203231A (en) * | 2016-05-11 | 2017-11-16 | パナソニックＩｐマネジメント株式会社 | Nonwoven fabric and sound absorption material |
-
1992
- 1992-04-17 JP JP9794592A patent/JP3164172B2/en not_active Expired - Fee Related
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005098118A1 (en) * | 2004-04-09 | 2005-10-20 | Mitsui Chemicals, Inc. | Nonwoven fabric sheet and method for producing same |
| JPWO2005098118A1 (en) * | 2004-04-09 | 2008-02-28 | 三井化学株式会社 | Non-woven sheet and method for producing the same |
| JP4787747B2 (en) * | 2004-04-09 | 2011-10-05 | 三井化学株式会社 | Non-woven sheet and method for producing the same |
| US8512610B2 (en) | 2004-04-09 | 2013-08-20 | Mitsui Chemicals, Inc. | Nonwoven fabric sheet and method for producing same |
| JP2009095731A (en) * | 2007-10-15 | 2009-05-07 | Kuraray Chem Corp | Filter for water treatment |
| JP2009233550A (en) * | 2008-03-26 | 2009-10-15 | Kuraray Co Ltd | Filter medium for gas filter |
| JP2010125404A (en) * | 2008-11-28 | 2010-06-10 | Mitsui Chemicals Inc | Liquid filter |
| JP2010137121A (en) * | 2008-12-09 | 2010-06-24 | Roki Techno Co Ltd | Filter having high differential pressure-proof performance and gel foreign matter elimination performance |
| US9200392B2 (en) | 2010-12-06 | 2015-12-01 | Mitsui Chemicals, Inc. | Melt-blown nonwoven fabric, and production process and apparatus for the same |
| US9404207B2 (en) | 2010-12-06 | 2016-08-02 | Mitsui Chemicals, Inc. | Melt-blown nonwoven fabric, and production process and apparatus for the same |
| JP2016053241A (en) * | 2011-01-28 | 2016-04-14 | タピルス株式会社 | Melt blown nonwoven fabric comprising ultrafine fiber and laminated processed product |
| JP2017203231A (en) * | 2016-05-11 | 2017-11-16 | パナソニックＩｐマネジメント株式会社 | Nonwoven fabric and sound absorption material |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3164172B2 (en) | 2001-05-08 |
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