JP2002172316A - Porous polytetrafluoroethylene film, and air-permeable laminate and filter unit prepared by using the same - Google Patents
Porous polytetrafluoroethylene film, and air-permeable laminate and filter unit prepared by using the sameInfo
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- JP2002172316A JP2002172316A JP2000371938A JP2000371938A JP2002172316A JP 2002172316 A JP2002172316 A JP 2002172316A JP 2000371938 A JP2000371938 A JP 2000371938A JP 2000371938 A JP2000371938 A JP 2000371938A JP 2002172316 A JP2002172316 A JP 2002172316A
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- ptfe
- air
- permeable
- porous membrane
- variation
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ポリテトラフルオ
ロエチレン（以下「ＰＴＦＥ」と略す）多孔質膜とこれ
を用いた通気性積層体およびフィルタユニットに関する
ものである。本発明は、特に、価粉体の回収や焼却炉の
粉塵の捕集するバグフィルタや、半導体工業や薬品工業
などのクリーンルームで使用されるエアフィルタに使用
されるＰＴＦＥ多孔質膜および通気性積層体に関するも
のである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polytetrafluoroethylene (hereinafter abbreviated as "PTFE") porous membrane, a gas-permeable laminate using the same, and a filter unit. In particular, the present invention relates to a PTFE porous membrane and a gas-permeable laminate used for a bag filter for collecting valence powder and collecting dust from an incinerator, and an air filter used in a clean room such as a semiconductor industry or a chemical industry. It is about the body.
【０００２】[0002]
【従来の技術】従来、有価粉塵の回収やバグフィルタを
用いた焼却炉では、各種フェルトや織布がろ材として多
く用いられている。しかし、このようなろ材は深層濾過
により粉体・粉塵を捕集するため、払い落とし性が悪
い。このため、圧力損失の上昇が速く、寿命が短くなる
という問題がある。2. Description of the Related Art Conventionally, various types of felts and woven fabrics have been widely used as filter media in incinerators using valuable dust collection and bag filters. However, since such a filter medium collects powders and dusts by deep-layer filtration, it has poor wiping properties. For this reason, there is a problem that the pressure loss rises quickly and the life is shortened.
【０００３】また、クリーンルームで使用されるエアフ
ィルタ用ろ材としては、ガラス繊維にバインダーを加え
て抄紙したものが多く用いられている。しかし、このよ
うなろ材には、濾材中の付着小繊維の存在、加工による
折曲げ時の自己発塵などの問題がある。また、ガラス繊
維ろ材には、フッ酸などある種の化学薬品と接触すると
劣化して発塵するという問題もある。さらに、バインダ
ー成分から気体成分が発生し、半導体などの製造歩留を
低下させるという問題も生じる。[0003] Further, as a filter medium for an air filter used in a clean room, a paper made by adding a binder to glass fiber is often used. However, such a filter medium has problems such as the presence of attached small fibers in the filter medium and self-dusting at the time of bending due to processing. Further, the glass fiber filter has a problem that it deteriorates and generates dust when it comes into contact with a certain chemical such as hydrofluoric acid. Further, a gas component is generated from the binder component, which causes a problem of lowering the production yield of semiconductors and the like.
【０００４】ＰＴＦＥはクリーンな材料であり、耐薬品
性にも優れている。そこで近年、ＰＴＦＥ延伸多孔質膜
が、有価粉塵の回収や焼却炉用、さらにはクリーンルー
ムで使用されるエアフィルタ用のろ材として使用されて
いる。特開平５−２０２２１７公報に記載されているＰ
ＴＦＥ多孔質膜はその一例である。[0004] PTFE is a clean material and has excellent chemical resistance. Therefore, in recent years, expanded PTFE porous membranes have been used as filter media for collecting valuable dust and incinerators, and also for air filters used in clean rooms. P described in JP-A-5-202217
TFE porous membrane is one example.
【０００５】ＰＴＦＥ多孔質膜にはコシがないため、一
般には他の通気性支持材により補強した積層体として使
用される。この積層体は、縫製加工がなされてバグフィ
ルタとなる。また、プリーツ加工したろ材に、ろ材間隔
を一定に保つためのビードを塗布して乾燥させた後、枠
付けしてエアフィルタユニットが作製される。[0005] Since the PTFE porous membrane has no stiffness, it is generally used as a laminate reinforced with another air-permeable supporting material. This laminate is sewn to form a bag filter. Further, a bead for keeping a constant filter medium interval is applied to the pleated filter medium, dried, and then framed to produce an air filter unit.
【０００６】[0006]
【発明が解決しようとする課題】半導体製造のクリーン
ルームに用いられるエアフィルタにおいては、エアフィ
ルタの風量分布が均一であることが求められる。風量分
布が不均一になれば、クリーンルーム中の空気の流れが
乱れ、空気が循環しない空気溜りが発生し、半導体の製
造歩留低下の原因となるガス成分の濃度が上昇するとい
う問題が生じる。An air filter used in a clean room for manufacturing semiconductors is required to have a uniform air volume distribution. If the air volume distribution becomes non-uniform, the flow of air in the clean room is disturbed, an air pocket in which the air does not circulate is generated, and the concentration of the gas component which causes a decrease in the production yield of the semiconductor is raised.
【０００７】通気性支持材の圧力損失はＰＴＦＥ多孔質
膜の圧力損失よりも低いため、ろ材の風量分布の均一性
は、ＰＴＦＥ多孔質膜の圧力損失の均一性に依存してい
る。ＰＴＦＥ多孔質膜の圧力損失の均一性を把握するた
めには、そのバラツキの度合いを評価することが必要と
なる。圧力損失の測定には、通常、直径１１０ｍｍの面
積が必要とされる。しかし、ＰＴＦＥ多孔質膜の圧力損
失の均一性は、ＰＴＦＥ多孔質膜の微多孔構造、すなわ
ち、延伸されたフィブリル（繊維）部およびノード（結
節）部の分布や形状にも影響を受けるため、上記のよう
に広い範囲を測定したのでは、バラツキ自体を正確に評
価できない。[0007] Since the pressure loss of the gas-permeable supporting material is lower than that of the porous PTFE membrane, the uniformity of the air volume distribution of the filter medium depends on the uniformity of the pressure loss of the porous PTFE membrane. In order to grasp the uniformity of the pressure loss of the PTFE porous membrane, it is necessary to evaluate the degree of the variation. Measurement of pressure loss usually requires an area of 110 mm in diameter. However, the uniformity of the pressure loss of the porous PTFE membrane is affected by the microporous structure of the porous PTFE membrane, that is, the distribution and shape of the stretched fibrils (fibers) and nodes (nodes). If the wide range is measured as described above, the variation itself cannot be accurately evaluated.
【０００８】このような事情もあって、従来は、風量分
布を均一化できるＰＴＦＥ多孔質膜については検討され
てこなかった。そこで、本発明は、風量分布を均一化で
きるＰＴＦＥ多孔質膜を提供することを目的とする。こ
の風量分布の均一化は、圧力損失の均一化をもたらすの
で、エアフィルタのみならず、バグフィルタにおいても
有意義である。バグフィルタにおいては、逆洗パルスエ
アーがかけられるが、圧力損失が均一であれば粉塵の払
い落としも均一化され、その後の捕集の際に捕集ムラが
生じにくい。このため、長期間の使用が可能となり、多
孔質膜の交換頻度を少なくできる。本発明は、上記ＰＴ
ＦＥ多孔質膜を用いた通気性積層体およびこれを用いた
フィルタユニットを提供することを目的とする。[0008] Under such circumstances, a PTFE porous membrane capable of making the air volume distribution uniform has not been studied. Therefore, an object of the present invention is to provide a PTFE porous membrane that can make the air volume distribution uniform. Since the uniform air volume distribution leads to uniform pressure loss, it is meaningful not only in the air filter but also in the bag filter. In the bag filter, backwash pulse air is applied. However, if the pressure loss is uniform, dust is uniformly removed, and uneven collection is unlikely to occur during subsequent collection. Therefore, it can be used for a long time, and the frequency of replacement of the porous membrane can be reduced. The present invention relates to the above PT
It is an object of the present invention to provide a breathable laminate using a FE porous membrane and a filter unit using the laminate.
【０００９】[0009]
【課題を解決するための手段】本発明者は、鋭意研究し
た結果、エアフィルタやバグフィルタに用いられるＰＴ
ＦＥ多孔質膜の微多孔構造の評価には、光学特性、特に
ヘイズ率が適していることを見出し、さらにヘイズ率を
評価の尺度としてＰＴＦＥ多孔質膜の微多孔構造の均一
化を図り、本発明を完成させた。すなわち、本発明のＰ
ＴＦＥ多孔質膜は、測定領域の相違によるヘイズ率のバ
ラツキが変動率により表示して２０％以下であることを
特徴とする。As a result of intensive studies, the present inventor has found that PTs used in air filters and bag filters are used.
For the evaluation of the microporous structure of the FE porous membrane, it was found that the optical properties, particularly the haze ratio, were suitable, and further, the haze ratio was used as a scale for evaluation to achieve uniformity of the microporous structure of the PTFE porous membrane. Completed the invention. That is, the P of the present invention
The TFE porous film is characterized in that the variation of the haze ratio due to the difference in the measurement area is not more than 20% as represented by the variation rate.
【００１０】変動率は、測定値の平均値に対するその標
準偏差の比により表される。ｎ個のデータ（Ｘ1、Ｘ2・・
・・Ｘｎ）の平均値をＸｍ、標準偏差をＳｘとすると、変
動率Ｖｘは次式により算出できる。[0010] The rate of change is represented by the ratio of its standard deviation to the average of the measurements. n data (X 1 , X 2 ...)
.. Xn), where Xm is the average value and Sx is the standard deviation, the variation rate Vx can be calculated by the following equation.
【００１１】変動率［％］；Ｖｘ＝Ｓｘ／Ｘｍ×１００Vx = Sx / Xm × 100
【００１２】また、ヘイズ率は、次式により表すことが
できる。 ヘイズ率［％］；拡散透過光量／全透過光量×１００Further, the haze ratio can be expressed by the following equation. Haze ratio [%]; diffused transmitted light amount / total transmitted light amount × 100
【００１３】データは、測定の対象とするＰＴＦＥ多孔
質膜において、互いに相違する少なくとも１０の領域に
おいて測定すること（標本数ｎ≧１０）が好ましい。測
定領域は、大きすぎるとバラツキが正確に評価できなく
なり、小さすぎると測定自体が正確に行えないため、５
０〜５００ｍｍ2程度とすることが好ましい。It is preferable that the data is measured in at least ten different regions of the PTFE porous membrane to be measured (the number of samples n ≧ 10). If the measurement area is too large, the variation cannot be accurately evaluated, and if it is too small, the measurement itself cannot be performed accurately.
It is preferable to set it to about 0 to 500 mm 2 .
【００１４】本発明は、上記ＰＴＦＥ多孔質膜を用いた
通気性積層体、さらにエアフィルタユニットまたはバグ
フィルタユニットも提供する。本発明の通気性積層体
は、上記ＰＴＦＥ多孔質膜と通気性支持材とが、それぞ
れ少なくとも１層ずつ含まれていることを特徴とする。
本発明のエアフィルタユニットまたはバグフィルタユニ
ットは、上記通気性積層体を用いたことを特徴としてお
り、例えば、連続したＷ字状にプリーツ加工された上記
通気性積層体（ろ材）と、このろ材を支持する部材とを
備えるものである。The present invention also provides a breathable laminate using the above-mentioned PTFE porous membrane, and further provides an air filter unit or a bag filter unit. The air-permeable laminate of the present invention is characterized in that the PTFE porous membrane and the air-permeable support material each include at least one layer.
The air filter unit or the bag filter unit according to the present invention is characterized by using the above-described air-permeable laminate, for example, the above-described air-permeable laminate (filter material) pleated in a continuous W shape, and the filter material. And a member for supporting.
【００１５】[0015]
【発明の実施の形態】以下、本発明の好ましい実施形態
を説明する。ＰＴＦＥ多孔質膜に入射した光の透過や散
乱は、ＰＴＦＥ多孔質膜の微多孔構造、具体的には気孔
率、フィブリル径、ノード面積などに影響される。ま
た、ＰＴＦＥ多孔質膜の膜厚にも左右される。光の透過
や散乱、特に透過光のヘイズ率は、ＰＴＦＥ多孔質膜の
微多孔構造の変化に対して感度が高いため、風量分布の
均一性の評価の基準として好適である。また、光学特性
は、小さい照射面積により測定できるため、ＰＴＦＥ多
孔質膜の微多孔構造の均一性の評価に適している。ＰＴ
ＦＥ多孔質膜のヘイズ率の変動率は、２０％以下、特に
１０）％以下が好適である。DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. The transmission or scattering of light incident on the PTFE porous membrane is affected by the microporous structure of the PTFE porous membrane, specifically, porosity, fibril diameter, node area, and the like. It also depends on the thickness of the PTFE porous film. The transmission and scattering of light, particularly the haze of transmitted light, is highly sensitive to changes in the microporous structure of the porous PTFE membrane, and is therefore suitable as a standard for evaluating the uniformity of the air volume distribution. Further, since the optical characteristics can be measured with a small irradiation area, it is suitable for evaluating the uniformity of the microporous structure of the PTFE porous film. PT
The fluctuation rate of the haze ratio of the FE porous film is preferably 20% or less, particularly preferably 10)% or less.
【００１６】全光線透過率の測定値に関する変動率も２
０％以下であることが好ましいが、ヘイズ率がＰＴＦＥ
多孔質膜の微多孔構造に対してより感度が高いため、こ
こではヘイズ率を採用する。ＰＴＦＥ多孔質膜のヘイズ
率の平均値は、特に制限されないが、ろ材として好まし
い特性を実現するためには４０％以上、特に５０％以上
であることが好ましい。ヘイズ率の平均値が４０％未満
となると、粒子の捕集性能が低下する場合がある。全光
線透過率の平均値も４０％以上、特に６０％以上である
ことが好ましい。全光線透過率の平均値が４０％未満と
なると、圧力損失が増大する場合がある。The variation rate of the measured value of the total light transmittance is also 2
It is preferably 0% or less, but the haze ratio is PTFE.
Since the sensitivity is higher for the microporous structure of the porous film, the haze ratio is adopted here. Although the average value of the haze ratio of the PTFE porous membrane is not particularly limited, it is preferably at least 40%, particularly preferably at least 50%, in order to realize preferable characteristics as a filter medium. If the average value of the haze ratio is less than 40%, the performance of collecting particles may decrease. The average value of the total light transmittance is preferably 40% or more, particularly preferably 60% or more. When the average value of the total light transmittance is less than 40%, the pressure loss may increase.
【００１７】ＰＴＦＥ多孔質膜を製造する方法の一例を
以下に説明する。まず、ＰＴＦＥファインパウダーに液
状潤滑剤を加えたペースト状の混和物を予備成形する。
液状潤滑剤は、ＰＴＦＥファインパウダーの表面を濡ら
すことができて、抽出や加熱により除去できるものであ
れば特に制限されず、例えば、流動パラフィン、ナフ
サ、ホワイトオイルなどの炭化水素を好適に使用でき
る。液状潤滑剤の添加量は、ＰＴＦＥファインパウダー
１００重量部に対して５〜５０重量部程度が適当であ
る。上記予備成形は、液状潤滑剤が絞り出されない程度
の圧力で行うことが好ましい。An example of a method for producing a porous PTFE membrane will be described below. First, a paste-like mixture obtained by adding a liquid lubricant to PTFE fine powder is preformed.
The liquid lubricant is not particularly limited as long as it can wet the surface of the PTFE fine powder and can be removed by extraction or heating. For example, hydrocarbons such as liquid paraffin, naphtha, and white oil can be suitably used. . An appropriate amount of the liquid lubricant is about 5 to 50 parts by weight based on 100 parts by weight of the PTFE fine powder. The preforming is preferably performed at such a pressure that the liquid lubricant is not squeezed out.
【００１８】こうして得た予備成形体を、押出および／
または圧延によってシート状に成形する。さらに、この
シート状のＰＴＦＥ成形体を一軸または二軸方向に延伸
してＰＴＦＥ多孔質シートを得る。なお、ＰＴＦＥ成形
体の延伸は、液状潤滑剤を除去してから行うことが好ま
しい。The preform thus obtained is extruded and / or
Alternatively, it is formed into a sheet by rolling. Further, the sheet-shaped PTFE molded body is stretched in a uniaxial or biaxial direction to obtain a PTFE porous sheet. The stretching of the PTFE molded body is preferably performed after removing the liquid lubricant.
【００１９】均一な微多孔構造を有するＰＴＦＥ多孔質
膜を得るためには、予備成形体を押出および／または圧
延する方向と直交する方向に、ＰＴＦＥ粒子の結着を強
めることが好ましい。ＰＴＦＥ粒子の結着を強めるに
は、予備成形した後、押出および／または圧延を行い、
次いで押出および／または圧延した方向と直交する方向
に、ＰＴＦＥ成形体に圧縮応力を加えればよい。In order to obtain a porous PTFE membrane having a uniform microporous structure, it is preferable to strengthen the binding of the PTFE particles in a direction perpendicular to the direction in which the preform is extruded and / or rolled. In order to strengthen the binding of PTFE particles, after preforming, extrusion and / or rolling are performed,
Next, a compressive stress may be applied to the PTFE molded body in a direction perpendicular to the direction of extrusion and / or rolling.
【００２０】例えば、棒状に押出し、さらに押出方向に
圧延したＰＴＦＥ成形体を、押出方向と直交する方向、
特に成形体の断面における長辺が圧縮される方向へとさ
らに圧延すると、ＰＴＦＥ粒子の結着が強くなる。圧縮
応力は、液状潤滑剤を除去する前に加えることが好まし
い。均一な微多孔構造が実現できれば、ヘイズ率の変動
率も低下する。For example, a PTFE molded body extruded in a rod shape and further rolled in the extrusion direction is placed in a direction perpendicular to the extrusion direction,
In particular, when further rolling is performed in a direction in which the long side in the cross section of the molded body is compressed, the binding of the PTFE particles becomes stronger. Preferably, the compressive stress is applied before removing the liquid lubricant. If a uniform microporous structure can be realized, the fluctuation rate of the haze ratio will also decrease.
【００２１】通気性支持材は、材質、構造、形態が特に
限定されるものではないが、ＰＴＦＥ多孔質膜よりも孔
径が大きく通気性に優れた材料、例えば、フェルト、不
織布、織布およびメッシュ（網目状シート）から選ばれ
るいずれかが好適であり、強度、柔軟性、作業性などの
点から不織布が特に好ましい。特に、通気性支持材とし
ては、不織布を構成する一部または全部の繊維が芯鞘構
造の複合繊維であり、芯成分が鞘成分より相対的に融点
が高い合成繊維とすることが好ましい。通気性支持材の
材料としては、特に限定するものではないが、例えば、
ポリオレフィン（ポリエチレン（ＰＥ）、ポリプロピレ
ン（ＰＰ）など）、ポリアミド、ポリエステル（ポリエ
チレンテレフタレート（ＰＥＴ）など）、芳香族ポリア
ミドあるいはこれらの複合材を用いることができる。The material, structure and form of the air-permeable supporting material are not particularly limited, but materials having a larger pore size than the PTFE porous membrane and excellent air permeability, such as felt, non-woven fabric, woven fabric and mesh Any one selected from (mesh-like sheet) is preferable, and a nonwoven fabric is particularly preferable in terms of strength, flexibility, workability, and the like. In particular, as the breathable support material, it is preferable that a part or all of the fibers constituting the nonwoven fabric is a composite fiber having a core-sheath structure, and the core component is a synthetic fiber having a relatively higher melting point than the sheath component. The material of the permeable support material is not particularly limited, for example,
Polyolefin (polyethylene (PE), polypropylene (PP), etc.), polyamide, polyester (polyethylene terephthalate (PET), etc.), aromatic polyamide, or a composite material thereof can be used.
【００２２】通気性支持材とＰＴＦＥ多孔質膜との積層
体（通気性積層体）を製造する方法は、特に限定され
ず、単に重ね合わせるだけでもよく、互いに接合しても
よい。接合は、例えば接着剤ラミネート、熱ラミネート
などの方法により行うことができる。例えば、熱ラミネ
ートにより積層する場合は、加熱により不織布など通気
性支持材の一部を溶融させて接着すればよい。また、ホ
ットメルトパウダーのような融着剤を介在させて接着し
てもよい。通気性積層体では、ＰＴＦＥ多孔質膜を連続
して積層してもよい。ＰＴＦＥ多孔質膜同士も、単に重
ね合わせるだけでもよいが、熱融着により、あるいはホ
ットメルトパウダーなどを用いて接合しても構わない。
ＰＴＦＥ多孔質膜は、成膜工程において圧着して積層し
てもよい。The method for producing a laminate (air-permeable laminate) of a gas-permeable support material and a porous PTFE membrane is not particularly limited, and may be simply superposed or joined together. Joining can be performed by a method such as adhesive lamination or heat lamination. For example, in the case of laminating by heat lamination, a part of a gas-permeable supporting material such as a nonwoven fabric may be melted and bonded by heating. Further, the bonding may be performed with a fusing agent such as hot melt powder interposed therebetween. In the breathable laminate, the PTFE porous membrane may be continuously laminated. The PTFE porous membranes may be simply overlapped with each other, but may be joined by heat fusion or using hot melt powder.
The PTFE porous film may be laminated by pressing in the film forming step.
【００２３】ＰＴＦＥ多孔質膜と通気性支持材とを積層
した通気性積層体を図１〜図３に例示する。図１の形態
では、通気性支持材としてフェルト２が用いられ、図２
および図３の形態では、通気性支持材として不織布３が
用いられている。図１および図２に示したように、１層
のＰＴＦＥ多孔質膜１を用いてもよく、図３に示したよ
うに、２層（またはそれ以上の層）のＰＴＦＥ多孔質膜
１を用いてもよい。FIGS. 1 to 3 show an example of a gas-permeable laminate obtained by laminating a porous PTFE membrane and a gas-permeable support material. In the embodiment of FIG. 1, a felt 2 is used as a gas-permeable supporting material, and FIG.
In the embodiment of FIG. 3, the nonwoven fabric 3 is used as the air-permeable supporting material. As shown in FIGS. 1 and 2, one layer of the PTFE porous membrane 1 may be used, and as shown in FIG. 3, two (or more) layers of the PTFE porous membrane 1 may be used. You may.
【００２４】各層の積層の順序および積層数は、図示し
た形態に限られない。また、通気性積層体には、用途に
応じて、親水化処理、撥油処理、撥水処理を施してもよ
い。The order of lamination of each layer and the number of laminations are not limited to the illustrated embodiment. The air-permeable laminate may be subjected to a hydrophilic treatment, an oil-repellent treatment, or a water-repellent treatment, depending on the use.
【００２５】[0025]
【実施例】以下、本発明を実施例によりさらに詳細に説
明するが、本発明は以下の実施例に制限されるものでは
ない。EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.
【００２６】（実施例１）ＰＴＦＥファインパウダー８
０重量部に液状潤滑剤（流動パラフィン）２０重量部を
加えたペースト状の混和物を予備成形し、ペースト押出
により丸棒状に成形した。次に、この成形体を断面の直
径が８０％に減少するように押出方向と同一方向に圧延
した。さらに、この成形体の断面の長辺方向が圧縮され
るように押出方向と直交する方向に圧延してシート状成
形体（厚さ０．３ｍｍ）を得た。液状潤滑剤をトリクレ
ンで抽出除去した後、シートの長さ方向および幅方向に
各２０倍延伸してＰＴＦＥ多孔質膜（厚さ：０．０１２
ｍｍ、平均孔径：１．１μｍ）を得た。(Example 1) PTFE fine powder 8
A paste-like admixture obtained by adding 20 parts by weight of a liquid lubricant (liquid paraffin) to 0 parts by weight was preliminarily molded and molded into a round bar by paste extrusion. Next, this compact was rolled in the same direction as the extrusion direction so that the cross-sectional diameter was reduced to 80%. Further, the formed body was rolled in a direction perpendicular to the extrusion direction so that the long side direction of the cross section was compressed, to obtain a sheet-shaped formed body (thickness 0.3 mm). After extracting and removing the liquid lubricant with trichlene, the sheet is stretched 20 times each in the length direction and width direction of the sheet to form a porous PTFE membrane (thickness: 0.012).
mm, average pore diameter: 1.1 μm).
【００２７】（実施例２）実施例１と同様にして予備成
形し、ペースト押出により成形した丸棒状の成形体を、
断面の直径が６０％に減少するように押出方向と同一方
向に圧延した。さらに、この成形体の断面の長辺方向が
圧縮されるように押出方向と直交する方向に圧延してシ
ート状成形体（厚さ：０．３ｍｍ）を得た。液状潤滑剤
を除去した後、シートの長さ方向および幅方向に各２０
倍延伸してＰＴＦＥ多孔質膜（厚さ：０．０１４ｍｍ、
平均孔径：１．０μｍ）を得た。(Example 2) A round bar-shaped molded product preformed and molded by paste extrusion in the same manner as in Example 1 was used.
Rolling was performed in the same direction as the extrusion direction so that the diameter of the cross section was reduced to 60%. Further, the formed body was rolled in a direction perpendicular to the extrusion direction so that the long side direction of the cross section was compressed, to obtain a sheet-shaped formed body (thickness: 0.3 mm). After removing the liquid lubricant, each of the sheets in the length and width directions is
Stretched twice to form a PTFE porous membrane (thickness: 0.014 mm,
(Average pore diameter: 1.0 μm).
【００２８】（実施例３）実施例２と同様にしてシート
状成形体（厚さ：０．３ｍｍ）を得た。液状潤滑剤を除
去した後、シートの長さ方向（押出方向と同一方向）に
１０倍、幅方向（押出方向と直交する方向）に２０倍延
伸したＰＴＦＥ多孔質膜（厚さ：０．０１８ｍｍ、平均
孔径：０．８μｍ）を得た。Example 3 A sheet-like molded product (thickness: 0.3 mm) was obtained in the same manner as in Example 2. After removing the liquid lubricant, a porous PTFE membrane (thickness: 0.018 mm) stretched 10 times in the sheet length direction (the same direction as the extrusion direction) and 20 times in the width direction (the direction orthogonal to the extrusion direction) , Average pore size: 0.8 μm).
【００２９】（比較例）実施例１と同様にして予備成形
し、ペースト押出により成形した丸棒状の成形体を、押
出方向と同一方向に圧延してシート状成形体（厚さ：
０．３ｍｍ）を得た。液状潤滑剤を除去した後、シート
の長さ方向および幅方向に各２０倍延伸してＰＴＦＥ多
孔質膜（厚さ：０．０１５ｍｍ、平均孔径：１．２μ
ｍ）を得た．(Comparative Example) A round bar-shaped compact preformed and paste-extruded in the same manner as in Example 1 was rolled in the same direction as the extrusion direction to form a sheet-shaped compact (thickness:
0.3 mm). After removing the liquid lubricant, the sheet is stretched 20 times in the length and width directions of the sheet to form a porous PTFE membrane (thickness: 0.015 mm, average pore diameter: 1.2 μm).
m) was obtained.
【００３０】実施例および比較例の各多孔質膜から、幅
方向に略等間隔で１４片の標本をサンプリングした。な
お、各標本の大きさは、縦横とも５ｃｍとした。各標本
について全光線透過率およびヘイズを測定した。測定に
は、日本電色工業製（株）製濁度計ＮＤＨ−１００１Ｄ
Ｐを使用した。なお、測定面積は、約９５ｍｍ2であっ
た。表１に、全光線透過率およびヘイズの平均値、標準
偏差および変動率を示す。Fourteen samples were sampled from the porous membranes of the examples and comparative examples at substantially equal intervals in the width direction. The size of each specimen was 5 cm both vertically and horizontally. The total light transmittance and haze of each sample were measured. For the measurement, a turbidity meter NDH-1001D manufactured by Nippon Denshoku Industries Co., Ltd. was used.
P was used. The measurement area was about 95 mm 2 . Table 1 shows the average value, the standard deviation, and the variation of the total light transmittance and the haze.
【００３１】 （表１） （％） ―――――――――――――――――――――――――――――――― 全光線透過率 ヘイズ率 平均値 標準偏差 変動率 平均値 標準偏差 変動率 ―――――――――――――――――――――――――――――――― 実施例１ 85.2 5.2 6.1 63.9 10.7 16.7 実施例２ 83.0 1.4 1.7 74.1 2.0 2.7 実施例３ 78.1 3.1 4.0 80.7 4.1 5.1 比較例１ 82.0 7.9 9.6 76.6 17.3 22.6 ――――――――――――――――――――――――――――――――(Table 1) (%) ―――――――――――――――――――――――――――――― Total light transmittance Haze rate Average value Standard deviation Fluctuation average Mean standard deviation Fluctuation ―――――――――――――――――――――――――――――― Example 1 85.2 5.2 6.1 63.9 10.7 16.7 Example 2 83.0 1.4 1.7 74.1 2.0 2.7 Example 3 78.1 3.1 4.0 80.7 4.1 5.1 Comparative Example 1 82.0 7.9 9.6 76.6 17.3 22.6 ―――――――――――――――――――――― ――――――――――
【００３２】実施例２でサンプリングした標本と、比較
例１でサンプリングした標本とを走査型電子顕微鏡によ
り観察したところ、実施例２は比較例１よりも押出方向
と直交する方向の粒子間結着が強いため、フィブリルの
数が多く、ノードの大きさも均一であった。このように
ＰＴＦＥ多孔質膜の微多孔構造のバラツキが、ヘイズ率
の変動率に影響していることが確認できた。When the sample sampled in Example 2 and the sample sampled in Comparative Example 1 were observed with a scanning electron microscope, Example 2 showed a larger binding than particles in Comparative Example 1 in the direction perpendicular to the extrusion direction. , The number of fibrils was large and the size of the nodes was uniform. Thus, it was confirmed that the variation in the microporous structure of the PTFE porous membrane affected the fluctuation rate of the haze ratio.
【００３３】[0033]
【発明の効果】以上説明したように、本発明によれば、
微多孔構造を均一化したＰＴＦＥ多孔質膜を提供でき
る。このＰＴＦＥ多孔質膜を用いることにより、フィル
タユニットにおける風量分布の均一化を図ることができ
る。As described above, according to the present invention,
A PTFE porous membrane having a uniform microporous structure can be provided. By using this PTFE porous membrane, the air volume distribution in the filter unit can be made uniform.
【図１】 本発明の通気性積層体の一形態を示す断面図
である。FIG. 1 is a cross-sectional view showing one embodiment of a breathable laminate of the present invention.
【図２】 本発明の通気性積層体の別の一形態を示す断
面図である。FIG. 2 is a cross-sectional view showing another embodiment of the breathable laminate of the present invention.
【図３】 本発明の通気性積層体のまた別の一形態を示
す断面図である。FIG. 3 is a cross-sectional view showing another embodiment of the breathable laminate of the present invention.
１ ＰＴＦＥ多孔膜質 ２ フェルト ３ 不織布 1 PTFE porous membrane 2 Felt 3 Non-woven fabric
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 4D006 GA44 HA42 MA09 MA26 MB03 MC30 PB17 PB19 PC05 PC73 4D019 AA01 BA13 BB02 BB03 BB04 BB08 BB10 BD01 4F074 AA27 AD02 AE01 CA03 CA06 CA51 CB33 CC02Y CC03Y CC24Y CC29Y DA03 DA10 DA23 DA43 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4D006 GA44 HA42 MA09 MA26 MB03 MC30 PB17 PB19 PC05 PC73 4D019 AA01 BA13 BB02 BB03 BB04 BB08 BB10 BD01 4F074 AA27 AD02 AE01 CA03 CA06 CA51 CB33 CC02Y CC03Y CC24 DA23
Claims (5)
キが変動率により表示して２０％以下であることを特徴
とするポリテトラフルオロエチレン多孔質膜。1. A polytetrafluoroethylene porous membrane, characterized in that the variation of the haze ratio due to the difference in the measurement area is not more than 20% as indicated by the variation rate.
求項１に記載のポリテトラフルオロエチレン多孔質膜。2. The polytetrafluoroethylene porous membrane according to claim 1, wherein the average value of the haze ratio is 40% or more.
ルオロエチレン多孔質膜と通気性支持材とが、それぞれ
少なくとも１層ずつ含まれていることを特徴とする通気
性積層体。3. A gas-permeable laminate comprising at least one layer each of the polytetrafluoroethylene porous membrane according to claim 1 and a gas-permeable support material.
不織布および織布から選ばれるいずれかである請求項３
に記載の通気性積層体。4. The air-permeable supporting material is made of felt, mesh,
4. A material selected from a non-woven fabric and a woven fabric.
The air-permeable laminate according to the above.
を用いたことを特徴とするフィルタユニット。5. A filter unit comprising the air-permeable laminate according to claim 3 or 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000371938A JP4526693B2 (en) | 2000-12-06 | 2000-12-06 | Polytetrafluoroethylene porous membrane, air-permeable laminate and filter unit using the same |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000371938A JP4526693B2 (en) | 2000-12-06 | 2000-12-06 | Polytetrafluoroethylene porous membrane, air-permeable laminate and filter unit using the same |
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| Publication Number | Publication Date |
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| JP2002172316A true JP2002172316A (en) | 2002-06-18 |
| JP4526693B2 JP4526693B2 (en) | 2010-08-18 |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1464382A1 (en) * | 2003-04-02 | 2004-10-06 | Yeu Ming Tai Chemical Industrial Co., Ltd. | Asymmetric porous polytetrafluoroethylene membrane for clothing |
| EP1464381A1 (en) * | 2003-04-02 | 2004-10-06 | Yeu Ming Tai Chemical Industrial Co., Ltd. | Asymmetric porous polytetrafluoroethylene membrane for a filter |
| JP2006061808A (en) * | 2004-08-26 | 2006-03-09 | Nitto Denko Corp | Ventilation filter medium for masks |
| JP2006175313A (en) * | 2004-12-21 | 2006-07-06 | Nitto Denko Corp | Filter medium for air filter and air filter unit |
| JP2009120775A (en) * | 2007-11-19 | 2009-06-04 | Sumitomo Electric Fine Polymer Inc | Surface modification method of fluororesin porous article |
| CN104497454A (en) * | 2014-12-01 | 2015-04-08 | 湖州绿净环保科技有限公司 | Polytetrafluoroethylene film for filtering air |
| JP2016147232A (en) * | 2015-02-12 | 2016-08-18 | 株式会社東芝 | Filer for filtration |
| JP2016147229A (en) * | 2015-02-12 | 2016-08-18 | 株式会社東芝 | Filter for filtration |
| US10994237B2 (en) * | 2017-11-13 | 2021-05-04 | W. L. Gore & Associates, Inc. | Filter bags comprising a porous membrane |
| JPWO2022071237A1 (en) * | 2020-09-30 | 2022-04-07 |
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| JP2000140588A (en) * | 1998-11-16 | 2000-05-23 | Nitto Denko Corp | Filter for dust collector |
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Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1464382A1 (en) * | 2003-04-02 | 2004-10-06 | Yeu Ming Tai Chemical Industrial Co., Ltd. | Asymmetric porous polytetrafluoroethylene membrane for clothing |
| EP1464381A1 (en) * | 2003-04-02 | 2004-10-06 | Yeu Ming Tai Chemical Industrial Co., Ltd. | Asymmetric porous polytetrafluoroethylene membrane for a filter |
| US7309663B2 (en) | 2003-04-02 | 2007-12-18 | Yeu Ming Tai Chemical Industrial Co., Ltd. | Asymmetric porous polytetrafluoroethylene membrane for clothing |
| US7374679B2 (en) | 2003-04-02 | 2008-05-20 | Yeu Ming Tai Chemical Industrial Co., Ltd. | Asymmetric porous polytetrafluoroethylene membrane for a filter |
| JP2006061808A (en) * | 2004-08-26 | 2006-03-09 | Nitto Denko Corp | Ventilation filter medium for masks |
| JP2006175313A (en) * | 2004-12-21 | 2006-07-06 | Nitto Denko Corp | Filter medium for air filter and air filter unit |
| JP2009120775A (en) * | 2007-11-19 | 2009-06-04 | Sumitomo Electric Fine Polymer Inc | Surface modification method of fluororesin porous article |
| CN104497454A (en) * | 2014-12-01 | 2015-04-08 | 湖州绿净环保科技有限公司 | Polytetrafluoroethylene film for filtering air |
| JP2016147232A (en) * | 2015-02-12 | 2016-08-18 | 株式会社東芝 | Filer for filtration |
| JP2016147229A (en) * | 2015-02-12 | 2016-08-18 | 株式会社東芝 | Filter for filtration |
| US10994237B2 (en) * | 2017-11-13 | 2021-05-04 | W. L. Gore & Associates, Inc. | Filter bags comprising a porous membrane |
| US11602711B2 (en) | 2017-11-13 | 2023-03-14 | W. L. Gore & Associates, Inc. | Filter bags comprising a porous membrane |
| JPWO2022071237A1 (en) * | 2020-09-30 | 2022-04-07 | ||
| WO2022071237A1 (en) * | 2020-09-30 | 2022-04-07 | 株式会社 潤工社 | Fluororesin film |
| JP7245424B2 (en) | 2020-09-30 | 2023-03-24 | 株式会社潤工社 | Fluororesin film |
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