JP7322457B2 - Multi-layer laminated filter media - Google Patents
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Description
本発明は多層積層濾材に関する。 The present invention relates to multi-layer laminated filter media.
近年、ＰＭ２．５等の大気汚染が問題となる中で、よりきれいな空気環境で生活を送りたいというニーズから、空気清浄機用フィルターや自動車用キャビンフィルター分野において、除塵性能と脱臭性能を両立する集塵脱臭濾材が求められている。除塵性能を有する濾材としては、繊維径の細い繊維で構成される不織布を用いた濾材が多く知られ、脱臭性能を有する濾材としては、粒子状あるいは繊維状の吸着剤をシート化する方法が多く知られている。例えば、複数の不織布間にガス除去粒子と接着パウダーの混合物を散布し、これを加熱溶融し接着してなる集塵脱臭濾材が開発されている（特許文献１）。 In recent years, air pollution such as PM2.5 has become a problem, and there is a need to live in a cleaner air environment. There is a need for a dust collecting and deodorizing filter medium. As filter media with dust-removing performance, many filter media using non-woven fabrics composed of fibers with a small fiber diameter are known, and as filter media with deodorizing performance, there are many methods in which particulate or fibrous adsorbents are formed into sheets. Are known. For example, a dust-collecting and deodorizing filter material has been developed in which a mixture of gas-removing particles and adhesive powder is dispersed between a plurality of non-woven fabrics, heated and melted, and adhered (Patent Document 1).
また、特許文献２では、吸着剤によって、吸着するガスが異なることから、揮発性有機化合物ガス（以下、VOCとすることがある）全般に対しての脱臭性能を高めるため、二種類の吸着剤を使用する濾材が開示されている。この濾材では、二層のシートのうちの一方のシートに所定の吸着剤を添着し、これら二層のシート間に、活性炭粉体を挟みこんでいる。 In addition, in Patent Document 2, since the adsorbed gas differs depending on the adsorbent, two types of adsorbents are used in order to improve the deodorizing performance for general volatile organic compound gases (hereinafter sometimes referred to as VOC). is disclosed. In this filter medium, a predetermined adsorbent is attached to one of the two-layered sheets, and activated carbon powder is sandwiched between the two-layered sheets.
特許文献１記載の濾材から、さらに脱臭性能を高めるために、ガス除去粒子の量を増やした場合、濾材の厚みが厚くなるため、二層の基材間が剥がれやすくなるという問題や、プリーツフィルターとした場合、１ユニットあたりの濾材面積が少なくなるといった問題があった。そこで、機能性粒子の一種である特定ガスを除去する吸着剤（以下、吸着剤と称することがある）の粒子径を小さくすると、粒子径の小さい吸着剤は表面積が大きいため、初期の脱臭性能は高めることができるが、一方で、脱臭性能の持続期間が短いものとなるとの課題がある。そして、吸着剤の粒子径を大きくすると、粒子径の大きい吸着剤は表面積が小さいため、脱臭性能の持続期間は長いものとなるが、一方で、初期の脱臭性能は低いものとなる。そこで、初期の脱臭性能に優れ、かつ脱臭性能の持続期間を長いものとするには、粒子径の小さい吸着剤と粒子径の大きい吸着剤とを併用混合し、この混合物を一つの不織布層間に配置することが考えられる。しかし、この場合には、大きな吸着剤同士の空隙に、小さい吸着剤が充填され、吸着剤が配置されている不織布層間の通気性が悪化し、さらには、濾材の通気性が悪化する（すなわち、圧力損失が高くなる）との問題が発生する。そこで、二つの不織布層間を有する濾材とし、この濾材が備える二つの層間のうちの一方に、粒子径の小さい吸着剤を配置し、この二つの層間のうちの他方に、粒子径の大きい吸着剤を配置することで上記問題を解決することが考えられるが、このような層構成が複雑な濾材にあっては、その製造課程も複雑なものとなり、生産性が悪化するという傾向がみられる。 If the amount of gas-removing particles is increased in order to further improve the deodorizing performance of the filter medium described in Patent Document 1, the thickness of the filter medium becomes thicker, which causes the problem that the two layers of substrates are easily peeled off. , there is a problem that the area of the filter medium per unit is reduced. Therefore, if the particle size of an adsorbent (hereinafter sometimes referred to as an adsorbent) that removes a specific gas, which is a type of functional particles, is reduced, the initial deodorizing performance can be increased, but on the other hand, there is a problem that the duration of the deodorizing performance is short. When the particle size of the adsorbent is increased, the adsorbent having a large particle size has a small surface area, so that the deodorizing performance lasts for a long time, but the initial deodorizing performance is low. Therefore, in order to have excellent initial deodorizing performance and a long duration of deodorizing performance, an adsorbent with a small particle size and an adsorbent with a large particle size are mixed together, and this mixture is placed between one nonwoven fabric layer. It is conceivable to place However, in this case, the gaps between large adsorbents are filled with small adsorbents, and the air permeability between the nonwoven fabric layers in which the adsorbents are arranged deteriorates, and furthermore, the air permeability of the filter material deteriorates (i.e. , pressure loss increases). Therefore, a filter medium having two non-woven fabric layers is used, an adsorbent with a small particle size is placed in one of the two layers of this filter medium, and an adsorbent with a large particle size is placed in the other of the two layers. Although it is possible to solve the above problem by arranging a filter medium with such a complicated layer structure, the manufacturing process is also complicated, and there is a tendency that productivity deteriorates.
そこで、本発明は、粒子径の大きい機能性粒子と粒子径の小さい機能性粒子を含み、圧力損失が低く、生産性にも優れる多層積層濾材を提供することを課題とする。 Therefore, an object of the present invention is to provide a multi-layer laminated filter medium that contains functional particles with a large particle size and functional particles with a small particle size, has a low pressure loss, and is excellent in productivity.
本発明者らは鋭意検討した結果、以下に示す手段により、上記課題を解決できることを見出し、本発明に到達した。本発明は以下のとおりである。
（１）少なくとも不織布B，不織布Aおよび不織布Ｃをこの順に備え、前記不織布Bと前記不織布Aとで形成される層間に機能性粒子Aが配置されており、
前記不織布Cと前記不織布Aとで形成される層間に機能性粒子Bが配置されており、下記式（１）を満たす、多層積層濾材、
不織布Ｂの最頻値ポアサイズ＜機能性粒子Ａの５０％粒子径（Ｄ５０）＜不織布Ａの最頻値ポアサイズ＜機能性粒子Ｂの５０％粒子径（Ｄ５０） （１）
（２）下記式（２）を満たす（１）の多層積層濾材、
不織布Ｂの最頻値ポアサイズ＜機能性粒子Ａの粒子径の１０％粒子径（D１０） （２）
（３）前記不織布Aおよび前記不織布Bの最頻値ポアサイズをDp（μｍ）とした場合、前記ポアサイズが０．８Ｄｐ～１．２Ｄｐである孔の細孔径分布の合計値が孔全体の４０％以上である（１）または（２）の多層積層濾材。
（４）（１）～（３）のいずれかの多層積層濾材の製造方法であって、
前記不織布Ｂを前記不織布Ａの鉛直下方に配置する工程と、
前記積層体の不織布A側の上方から、前記積層体に前記機能性粒子Ａと前記機能性粒子Ｂとを含有する混合物を散布するとの工程とをこの順に有する、多層積層濾材の製造方法である。
As a result of intensive studies, the inventors of the present invention have found that the above problems can be solved by means shown below, and have completed the present invention. The present invention is as follows.
(1) At least nonwoven fabric B, nonwoven fabric A and nonwoven fabric C are provided in this order, and functional particles A are arranged between layers formed by the nonwoven fabric B and the nonwoven fabric A,
A multi-layer laminated filter medium in which functional particles B are arranged between the layers formed of the nonwoven fabric C and the nonwoven fabric A, and which satisfies the following formula (1),
Mode pore size of nonwoven fabric B<50% particle size of functional particles A (D50)<mode pore size of nonwoven fabric A<50% particle size of functional particles B (D50) (1)
(2) the multi-layer laminated filter medium of (1) that satisfies the following formula (2);
Mode pore size of nonwoven fabric B < 10% particle size of functional particle A particle size (D10) (2)
(3) When the mode pore size of the nonwoven fabric A and the nonwoven fabric B is Dp (μm), the total value of the pore size distribution of the pores having a pore size of 0.8 Dp to 1.2 Dp is 40% of the entire pores. The multi-layer laminated filter medium of (1) or (2) above.
(4) A method for producing a multi-layer laminated filter medium according to any one of (1) to (3),
A step of arranging the nonwoven fabric B vertically below the nonwoven fabric A;
and a step of spraying a mixture containing the functional particles A and the functional particles B onto the laminate from above the nonwoven fabric A side of the laminate in this order. .
本発明によれば、圧力損失が低く、脱臭性能に優れるとともに、生産性にも優れる多層積層濾材を提供することができる。 According to the present invention, it is possible to provide a multi-layer laminated filter medium with low pressure loss, excellent deodorizing performance, and excellent productivity.
以下、本発明について詳細に説明する。
The present invention will be described in detail below.
本発明の多層積層濾材は、少なくとも不織布B，不織布Aおよび不織布Ｃをこの順に備え、不織布Bと不織布Aとで形成される層間（以下、層間Ａと称することがある）には機能性粒子Aが配置されており、不織布Cと不織布Aとで形成される層間（以下、層間Ｂと称することがある）には機能性粒子Bが配置されている。また、この多層積層濾材においては、不織布Ｂの最頻値ポアサイズ＜機能性粒子Ａの５０％粒子径（Ｄ５０）＜不織布Ａの最頻値ポアサイズ＜機能性粒子Ｂの５０％粒子径（Ｄ５０）の関係が成立する。 The multi-layer laminated filter medium of the present invention comprises at least nonwoven fabric B, nonwoven fabric A and nonwoven fabric C in this order, and between layers formed by nonwoven fabric B and nonwoven fabric A (hereinafter sometimes referred to as layer A) functional particles A are arranged, and the functional particles B are arranged between the layers formed by the nonwoven fabric C and the nonwoven fabric A (hereinafter sometimes referred to as the interlayer B). In this multi-layer laminated filter medium, the mode pore size of nonwoven fabric B<50% particle size of functional particles A (D50)<mode pore size of nonwoven fabric A<50% particle size of functional particles B (D50) relationship is established.
以下、機能性粒子Ａの５０％粒子径（Ｄ５０）を機能性粒子ＡのＤ５０、機能性粒子Ｂの５０％粒子径（Ｄ５０）を機能性粒子ＢのＤ５０と称することがある。 Hereinafter, the 50% particle size (D50) of functional particles A is sometimes referred to as D50 of functional particles A, and the 50% particle size (D50) of functional particles B is sometimes referred to as D50 of functional particles B.
このような構成を採用する本発明の多層積層濾材は、以下のメカニズムにて、本発明の効果を奏するものと考える。まず、上記のとおり、機能性粒子ＡのＤ５０＜機能性粒子ＢのＤ５０の関係にある機能性粒子Ａと機能性粒子Ｂとは、それぞれ層間Ａと層間Ｂとに分けて配置されている。このことにより、一つの層間に機能性粒子Ａと機能性粒子Ｂとが混在する際にみられる、機能性粒子Ｂ同士の隙間に機能性粒子Ａが充填されるといった現象の発生が抑制される。これにより、層間における通気性の低下が抑制されるので、結果として、本発明の多層積層濾材の通気性は優れたものとなり、本発明の多層積層濾材の圧力損失は低いものとなる。また、機能性粒子Ａと機能性粒子Ｂとを備える本発明の多層積層濾材の脱臭性能も優れたものとなる。そして、本発明の多層積層濾材では、上記のことに加え、不織布Ｂの最頻値ポアサイズ＜機能性粒子Ａの５０％粒子径（Ｄ５０）＜不織布Ａの最頻値ポアサイズ＜機能性粒子Ｂの５０％粒子径（Ｄ５０）の関係が成立している。よって、この多層積層濾材の製造方法として、以下のものが採用し得る。まず、不織布Ｂを不織布Ａの鉛直方向下方に配置する工程を得て、次に、この不織布A側の上方から、機能性粒子Ａと機能性粒子Ｂとの混合物を散布するとの工程を有する多層積層濾材の製造方法である。この製造方法では、上記の関係により、機能性粒子Ｂは不織布Ａの上に保持されるが、機能性粒子Ａは不織布Ａを通過したのち、不織布Ｂに保持される。よって、この製造方法では、１回の機能性粒子の散布にて、不織布の積層体の異なる層間に、機能性粒子Ａおよび機能性粒子Ｂを分けて配置することが可能であり、このような製造方法を採用することができる本発明の多層積層濾材は生産性に優れたものであるといえる。すなわち、本発明の多層積層濾材は、上記の理由により、脱臭性能と通気性とに優れ、かつ、圧力損失が低いのみではなく、生産性にも優れたものである。 It is considered that the multi-layer laminated filter medium of the present invention adopting such a configuration exhibits the effects of the present invention through the following mechanism. First, as described above, the functional particles A and the functional particles B having the relation of D50 of the functional particles A<D50 of the functional particles B are arranged separately between the interlayers A and B, respectively. This suppresses the occurrence of the phenomenon that the functional particles A are filled in the gaps between the functional particles B, which is observed when the functional particles A and B are mixed in one layer. . As a result, a decrease in air permeability between layers is suppressed, and as a result, the air permeability of the multi-layer laminated filter medium of the present invention is excellent, and the pressure loss of the multi-layer laminated filter medium of the present invention is low. Moreover, the deodorizing performance of the multi-layer laminated filter medium of the present invention comprising functional particles A and functional particles B is also excellent. In addition to the above, in the multilayer laminated filter medium of the present invention, in addition to the above, the mode pore size of nonwoven fabric B < 50% particle size (D50) of functional particles A < mode pore size of nonwoven fabric A < functional particles B A relationship of 50% particle size (D50) is established. Therefore, the following method can be adopted as a method for manufacturing this multi-layer laminated filter medium. First, a step of arranging nonwoven fabric B vertically below nonwoven fabric A is obtained, and then a mixture of functional particles A and functional particles B is dispersed from above the nonwoven fabric A side. A method for manufacturing a laminated filter medium. In this manufacturing method, the functional particles B are held on the nonwoven fabric A due to the above relationship, and the functional particles A are held on the nonwoven fabric B after passing through the nonwoven fabric A. Therefore, in this production method, it is possible to separately arrange the functional particles A and the functional particles B between different layers of the nonwoven fabric laminate by spraying the functional particles once. It can be said that the multi-layer laminated filter medium of the present invention, for which the production method can be employed, is excellent in productivity. That is, for the reasons described above, the multi-layer laminated filter medium of the present invention not only has excellent deodorizing performance and air permeability and low pressure loss, but also excellent productivity.
以下に、本発明の多層積層濾材に用いる部材について説明する。 The members used in the multi-layer laminated filter medium of the present invention are described below.
本発明の多層積層濾材に用いる不織布は、特に限定されるものではなく、エアレイド不織布、湿式不織布、スパンボンド不織布、メルトブロー不織布、サーマルボンド不織布、ニードルパンチ不織布、スパンレース不織布などから任意に選択できる。高い除塵性能および高い通気性を得るため、少なくとも一層は、メルトブロー不織布または上記のメルトブロー不織布にエレクトレット加工を施したものが好ましく、さらに、平均繊維径が３μｍ以下のメルトブロー不織布または上記のメルトブロー不織布にエレクトレット加工を施したものがより好ましい。また、フィルター加工時のプリーツ形状の保持性を得るため、少なくとも一層は、ガーレ剛軟度が３００ｍｇ以上の不織布を用いることがより好ましい。ここで、平均繊維径の求め方は次のとおりである。１０００ｍｍ×１０００ｍｍの不織布の面上から２０個のサンプル取得箇所を無作為に選定し、各サンプル取得箇所１個あたり１個のタテ×ヨコ＝３ｍｍ×３ｍｍの測定サンプルを採取し、走査型電子顕微鏡（倍率：１０００倍）により不織布の表面写真を各測定サンプル１枚あたり１枚ずつ、計２０枚を撮影し、写真の中の全ての繊維について繊維径を測定する。各繊維径は、有効数字０．１μｍの測定精度にて行い、写真に写った全ての繊維の本数を(a)とし、写真に写った繊維径が０．１μｍ以上３．０μｍ以下の繊維の本数を（ｂ）とする。次に、次式により、繊維径０．１μｍ以上３．０μｍ以下の繊維の数の比を計算する。 The nonwoven fabric used in the multi-layer laminated filter medium of the present invention is not particularly limited, and can be arbitrarily selected from air-laid nonwoven fabrics, wet-laid nonwoven fabrics, spunbond nonwoven fabrics, meltblown nonwoven fabrics, thermal bond nonwoven fabrics, needle punch nonwoven fabrics, spunlace nonwoven fabrics, and the like. In order to obtain high dust removal performance and high air permeability, at least one layer is preferably a melt-blown nonwoven fabric or the above-mentioned melt-blown non-woven fabric subjected to electret processing, and further, a melt-blown non-woven fabric having an average fiber diameter of 3 μm or less or the above-mentioned melt-blown non-woven fabric electret. A processed one is more preferable. Moreover, in order to obtain the retention of the pleated shape during filter processing, it is more preferable to use a nonwoven fabric having a Gurley bending resistance of 300 mg or more for at least one layer. Here, the method for obtaining the average fiber diameter is as follows. Randomly select 20 sample acquisition points from the surface of the nonwoven fabric of 1000 mm × 1000 mm, collect one vertical × horizontal = 3 mm × 3 mm measurement sample per each sample acquisition point, and scan electron microscope. (Magnification: 1000 times) to take a total of 20 photographs of the surface of the nonwoven fabric, one for each measurement sample, and measure the fiber diameter of all the fibers in the photographs. Each fiber diameter is measured with an effective figure of 0.1 μm, the number of all fibers in the photograph is (a), and the fiber diameter in the photograph is 0.1 μm or more and 3.0 μm or less. Let the number be (b). Next, the ratio of the number of fibers with a fiber diameter of 0.1 μm or more and 3.0 μm or less is calculated by the following formula.
（繊維径０．１μｍ以上３．０μｍ以下の繊維の数比）＝（ｂ）／（ａ）
本発明の多層積層濾材に用いる機能性粒子は、特に限定されるものではなく、脱臭剤、芳香剤、抗菌剤、防カビ剤、難燃剤等が使用できる。特に脱臭剤として機能する機能性粒子としては、活性炭、無機多孔質体、イオン交換樹脂等が挙げられ、これらの機能性粒子は単独で用いることもできるし、複合して用いることもできる。また、脱臭剤として機能する機能性粒子は除去対象とするガス成分との反応性を高める目的で薬剤が添着されたものであってもよい。その場合の薬剤としては特に限定されるものではないが、例えばアンモニアなどの塩基性ガスを除去する場合はリン酸や塩酸などが挙げられ、酢酸や二酸化硫黄などの酸性ガスを除去する場合は水酸化カリウム、炭酸カリウム、炭酸水素カリウム、炭酸ナトリウム、炭酸水素ナトリウムが挙げられる。さらにアルデヒド系のガスに対しては第一級から第三級アミン化合物であるアジピン酸ジヒドラジド、コハク酸ジヒドラジド、カルボジヒドラジドなどのヒドラジド化合物やｐ－アミノベンゼンスルホン酸、エチレン尿素縮合体薬剤などが挙げられる。薬剤の添着量としては脱臭剤の質量に対して１．５～３０質量％が好ましく、より好ましくは２～２０質量％である。
(Number ratio of fibers with a fiber diameter of 0.1 μm or more and 3.0 μm or less) = (b) / (a)
The functional particles used in the multi-layer laminated filter medium of the present invention are not particularly limited, and deodorants, fragrances, antibacterial agents, antifungal agents, flame retardants and the like can be used. In particular, functional particles that function as deodorants include activated carbon, inorganic porous materials, ion-exchange resins, etc. These functional particles can be used alone or in combination. Moreover, the functional particles functioning as a deodorant may be those to which a chemical agent is attached for the purpose of enhancing the reactivity with the gas component to be removed. The agent in that case is not particularly limited, but for example, phosphoric acid and hydrochloric acid can be used when removing basic gases such as ammonia, and water can be used when removing acid gases such as acetic acid and sulfur dioxide. Potassium oxide, potassium carbonate, potassium hydrogencarbonate, sodium carbonate, sodium hydrogencarbonate. Further, for aldehyde gases, hydrazide compounds such as primary to tertiary amine compounds such as adipic acid dihydrazide, succinic acid dihydrazide, and carbodihydrazide, p-aminobenzenesulfonic acid, and ethylene urea condensate agents are listed. be done. The amount of the chemical attached is preferably 1.5 to 30% by mass, more preferably 2 to 20% by mass, based on the mass of the deodorant.
機能性粒子ＢのＤ５０は、６００μｍ以下が好ましい。機能性粒子ＢのＤ５０を６００μｍ以下とすることで、脱臭剤が不織布層を突き破りにくくなり、多層積層濾材の折り曲げ加工等の後加工が容易となる。また、機能性粒子ＢのＤ５０は、不織布Ａの最頻値ポアサイズより大きい必要がある。機能性粒子ＢのＤ５０が、不織布Ａの最頻値ポアサイズより小さい場合、不織布Ａを通り抜けて、層間Ｂとなる粒子が多くなり、機能性粒子Ｂ同士の隙間に機能性粒子Ａが充填され、通気性が低下するためである。機能性粒子ＡのＤ５０は、1００μｍ以下であることが好ましい。機能性粒子ＡのＤ５０が１００μｍ以下の小さな粒子ほど、粒子間の隙間が詰まりやすいため、層間に分ける本発明の効果がより得やすい。また、機能性粒子ＡのＤ５０は不織布Ｂの最頻値ポアサイズより大きい必要がある。機能性粒子ＡのＤ５０が、不織布Ｂの最頻値ポアサイズより小さい場合、不織布Ｂを通り抜けて、脱落する粒子が多くなり、脱落した粒子は廃棄されるため、生産ロスにつながる。また、生産設備の清掃頻度を高くする必要が生じ、生産性が悪化する。さらに次の関係を満たすことで、機能性粒子Ａが不織布Ｂから抜けて脱落することさらに抑制できる。
不織布Ｂの最頻値ポアサイズ＜機能性粒子Ａの粒子径の１０％粒子径（D１０）
ここで、機能性粒子のＤ１０およびＤ５０はそれぞれ、１００個の機能性粒子について、機能性粒子の粒子径（Ｆｅｒｅｔ径）を測定して得られる粒子径個数分布において、粒子径の小さい方から累積して１０個数％および５０個数％になる点における粒子径をいう。 また、不織布の最頻値ポアサイズとは、バブルポイント法（ＡＳＴＭＦ－３１６－８６に基づく）によって算出される不織布の最頻値ポアサイズをいう。
D50 of the functional particles B is preferably 600 μm or less. By setting the D50 of the functional particles B to 600 μm or less, the deodorant is less likely to break through the nonwoven fabric layer, and post-processing such as folding of the multi-layered filter medium is facilitated. Moreover, D50 of the functional particles B must be larger than the mode pore size of the nonwoven fabric A. When the D50 of the functional particles B is smaller than the mode pore size of the nonwoven fabric A, the number of particles passing through the nonwoven fabric A to become the interlayer B increases, and the gaps between the functional particles B are filled with the functional particles A, This is because the air permeability decreases. D50 of the functional particles A is preferably 100 μm or less. As the functional particles A have a smaller D50 of 100 μm or less, the gaps between the particles are more likely to be clogged, so the effects of the present invention for separating between layers are more likely to be obtained. In addition, the D50 of the functional particles A must be larger than the mode pore size of the nonwoven fabric B. When the D50 of the functional particles A is smaller than the mode pore size of the nonwoven fabric B, many particles pass through the nonwoven fabric B and drop off, and the dropped particles are discarded, leading to production loss. In addition, it becomes necessary to increase the frequency of cleaning the production equipment, which deteriorates productivity. Furthermore, by satisfying the following relationship, it is possible to further suppress the functional particles A from falling out of the nonwoven fabric B.
Mode pore size of nonwoven fabric B < 10% particle size of functional particle A particle size (D10)
Here, D10 and D50 of the functional particles are respectively cumulative from the smaller particle diameter in the particle diameter number distribution obtained by measuring the particle diameter (Feret diameter) of the functional particles for 100 functional particles. It refers to the particle diameter at the point of 10% by number and 50% by number. Moreover, the mode pore size of the nonwoven fabric refers to the mode pore size of the nonwoven fabric calculated by the bubble point method (based on ASTM F-316-86).
機能性粒子Ｂの目付けは、５００g/m2以下が好ましく、３００g/m2以下がより好ましい。５００g/m2以下とすることで、多層積層濾材の厚みが厚くなりすぎず、折り曲げ加工等の後加工が容易となる。機能性粒子Aの目付けは、１００ｇ/ｍ２以下が好ましく、８０ｇ/ｍ２以下がより好ましい。例えば、５０％粒子径（Ｄ５０）が１００μｍの場合でも、機能性粒子Aの目付けを１００ｇ/ｍ２以下とすることで、粒子間の空隙が詰まることによる通気性の悪化を抑制することができる。８０ｇ/ｍ２以下とすることでより通気性が特に優れたものとなり、圧力損失の上昇をより抑えることができる。また、機能性粒子Ｂおよび機能性粒子Ａの目付けは、５g/m2以上が好ましい。５g/m2以上とすることで、不織布への散布ムラを低減することができる。 The basis weight of functional particles B is preferably 500 g/m 2 or less, more preferably 300 g/m 2 or less. By making it 500 g/m 2 or less, the thickness of the multi-layered filter medium does not become too thick, and post-processing such as bending is facilitated. The basis weight of the functional particles A is preferably 100 g/m 2 or less, more preferably 80 g/m 2 or less. For example, even when the 50% particle size (D50) is 100 μm, by setting the basis weight of the functional particles A to 100 g/m 2 or less, it is possible to suppress deterioration of air permeability due to clogging of voids between particles. . By setting it to 80 g/m 2 or less, the air permeability becomes particularly excellent, and an increase in pressure loss can be further suppressed. Moreover, the basis weight of functional particles B and functional particles A is preferably 5 g/m 2 or more. By setting the amount to 5 g/m 2 or more, it is possible to reduce unevenness in application to the nonwoven fabric.
本発明の多層積層濾材は、この多層積層濾材の有する複数の層間において機能性粒子を保持するのに、上記の層間に機能性粒子に加えてバインダー樹脂を有していることが好ましい。このバインダー樹脂としては、熱可塑性樹脂を用いることができる。熱可塑性樹脂の種類としては、ポリオレフィン系樹脂、ポリアミド系樹脂、ポリエステル系樹脂、エチレン－アクリル共重合体等が挙げられる。また、本発明の多層積層濾材の製造工程において、不織布上に散布されるバインダー樹脂の形状は、特に限定されるものではなく、球状、破砕状等が挙げられる。また、２種類以上の熱可塑性樹脂のバインダー樹脂を併用しても良い。多層積層濾材に含まれる熱可塑性樹脂（バインダー樹脂）の量は、機能性粒子の質量に対し、５～４０質量％が好ましい。この範囲内であれば、機能性粒子の脱落が抑制され、かつ、通気性にも優れた多層積層濾材が得られる。 The multilayer filter medium of the present invention preferably has a binder resin between the layers in addition to the functional particles in order to hold the functional particles between the layers of the multilayer filter medium. A thermoplastic resin can be used as the binder resin. Types of thermoplastic resins include polyolefin resins, polyamide resins, polyester resins, ethylene-acrylic copolymers, and the like. In addition, in the manufacturing process of the multi-layer laminated filter medium of the present invention, the shape of the binder resin dispersed on the non-woven fabric is not particularly limited, and may be spherical, pulverized, or the like. Also, two or more thermoplastic resin binder resins may be used in combination. The amount of the thermoplastic resin (binder resin) contained in the multi-layered filter medium is preferably 5 to 40 mass % with respect to the mass of the functional particles. Within this range, it is possible to obtain a multi-layer laminated filter medium in which dropout of the functional particles is suppressed and which is also excellent in air permeability.
本発明では、多層積層濾材を構成する各不織布と各機能性粒子とが次の関係である。 In the present invention, the relationship between each nonwoven fabric and each functional particle constituting the multi-layered filter medium is as follows.
すなわち、不織布Ｂの最頻値ポアサイズ＜機能性粒子Ａの５０％粒子径（Ｄ５０）＜不織布Ａの最頻値ポアサイズ＜機能性粒子Ｂの５０％粒子径（Ｄ５０） である。 That is, the mode pore size of nonwoven fabric B<50% particle size of functional particles A (D50)<mode pore size of nonwoven fabric A<50% particle size of functional particles B (D50).
ここで、上記関係を満たすことで、不織布Ａによる篩効果により、後に述べる製造方法にあるように、一回の機能性粒子の散布工程で、多層積層濾材を得ることができ、この多層積層濾材の生産性が大きく向上する。 Here, by satisfying the above relationship, the sieving effect of the nonwoven fabric A enables the multi-layer laminated filter medium to be obtained in a single functional particle dispersion process, as in the manufacturing method described later. productivity is greatly improved.
また、本発明では、不織布Aおよび不織布Bの最頻値ポアサイズをDp（μｍ）とした場合、前記ポアサイズが０．８Ｄｐ～１．２Ｄｐである孔の細孔径分布の合計値が孔全体の４０％以上であることが好ましい。０．８Ｄｐ～１．２Ｄｐである孔の細孔径分布の合計値が４０％以上の不織布は、細孔径分布のばらつきが小さく、本発明における不織布による篩効果が顕著となる。 Further, in the present invention, when the mode pore size of nonwoven fabric A and nonwoven fabric B is Dp (μm), the total value of the pore size distribution of the pores having a pore size of 0.8 Dp to 1.2 Dp is 40% of the entire pores. % or more. A nonwoven fabric having a total pore size distribution of 40% or more of pores of 0.8 Dp to 1.2 Dp has a small variation in pore size distribution, and the sieving effect of the nonwoven fabric in the present invention is remarkable.
本発明における多層積層濾材の製造方法の一例について説明する。この製造方法の一例では、熱可塑性樹脂Ａの粒状物（以下、熱可塑性樹脂粒子Aと称することがある）および熱可塑性樹脂Ｂの粒状物（以下、熱可塑性樹脂粒子Bと称することがある）を用いているが、これらの熱可塑性樹脂粒子を用いることは、本発明の多層積層濾材の製造方法において必須ではない。ここで、熱可塑性樹脂粒子Ａの５０％粒子径（Ｄ５０）（以下、熱可塑性樹脂粒子ＡのＤ５０と称することがある）と機能性粒子ＡのＤ５０との比（熱可塑性樹脂粒子ＡのＤ５０／機能性粒子ＡのＤ５０）は０．７～１．３であることが好ましく、熱可塑性樹脂粒子Ｂの５０％粒子径（Ｄ５０）（以下、熱可塑性樹脂粒子ＢのＤ５０と称することがある）と機能性粒子ＢのＤ５０との比（熱可塑性樹脂粒子ＢのＤ５０／機能性粒子ＢのＤ５０）は０．７～１．３であることが好ましい。熱可塑性樹脂粒子Ｂと機能性粒子Ｂとの比を０．７以上とすることで、熱可塑性樹脂粒子Ｂの多くが不織布Ａから抜けて層間Ａに脱落することを防ぐことができ、層間Ｂの接着性を保つことができる。熱可塑性樹脂粒子Ａと機能性粒子Ａとの比を０．７以上とすることで、熱可塑性樹脂粒子Aの多くが不織布Ｂから抜けて脱落することを防ぐことができ、層間Ａの接着性を保つことができるとともに、前述のように、脱落した接着剤により生産頻度が高くなることによる生産性の悪化を防ぐことができる。熱可塑性樹脂粒子と機能性粒子との比を１．３以下とすることで、熱可塑性樹脂粒子の散布ムラの発生を抑えることができる。例えば、同重量の熱可塑性樹脂粒子を比較した場合、粒子径の大きい熱可塑性樹脂が、より個数が少なくなるため、散布ムラが発生しやすくなると考える。 An example of the method for manufacturing the multilayered filter medium of the present invention will be described. In one example of this production method, particulate matter of thermoplastic resin A (hereinafter sometimes referred to as thermoplastic resin particles A) and particulate matter of thermoplastic resin B (hereinafter sometimes referred to as thermoplastic resin particles B) is used, but the use of these thermoplastic resin particles is not essential in the method for producing the multi-layer laminated filter medium of the present invention. Here, the ratio of the 50% particle diameter (D50) of the thermoplastic resin particles A (hereinafter sometimes referred to as D50 of the thermoplastic resin particles A) to the D50 of the functional particles A (D50 of the thermoplastic resin particles A / D50 of functional particles A) is preferably 0.7 to 1.3, 50% particle diameter (D50) of thermoplastic resin particles B (hereinafter sometimes referred to as D50 of thermoplastic resin particles B ) to the D50 of the functional particles B (D50 of the thermoplastic resin particles B/D50 of the functional particles B) is preferably 0.7 to 1.3. By setting the ratio of the thermoplastic resin particles B to the functional particles B to 0.7 or more, it is possible to prevent most of the thermoplastic resin particles B from falling out of the nonwoven fabric A and into the interlayer A. can maintain the adhesiveness of By setting the ratio of the thermoplastic resin particles A to the functional particles A to 0.7 or more, it is possible to prevent most of the thermoplastic resin particles A from coming out of the nonwoven fabric B and falling off, and the adhesion of the interlayer A can be maintained, and as described above, it is possible to prevent deterioration of productivity due to an increase in production frequency due to the dropped adhesive. By setting the ratio of the thermoplastic resin particles to the functional particles to 1.3 or less, it is possible to suppress the occurrence of uneven distribution of the thermoplastic resin particles. For example, when thermoplastic resin particles of the same weight are compared, the number of thermoplastic resin particles having a large particle size is smaller, so it is considered that uneven distribution tends to occur.
まず、機能性粒子Ａおよび機能性粒子Ｂと熱可塑性樹脂粒子Ａおよび熱可塑性樹脂粒子Ｂを所定の質量秤量し、混合し混合粒子を得る。混合粒子における、熱可塑性樹脂粒子Aの質量は機能性粒子Aの５～４０質量％が好ましく、熱可塑性樹脂粒子Bの質量は機能性粒子Bの５～４０質量％が好ましい。 First, the functional particles A and functional particles B and the thermoplastic resin particles A and thermoplastic resin particles B are weighed by a predetermined mass and mixed to obtain mixed particles. The mass of the thermoplastic resin particles A in the mixed particles is preferably 5 to 40% by mass of the functional particles A, and the mass of the thermoplastic resin particles B is preferably 5 to 40% by mass of the functional particles B.
次に、不織布Ｂを不織布Ａの鉛直方向下方に配置する。このとき、不織布Aと不織布Bの間隙は、１ｃｍ以上、２０ｃｍ以下であることが好ましい。この範囲内であれば、機能性粒子Aが不織布Aを効率良くすり抜け、また散布ムラや飛散も生じにくい。そして、この不織布A側の上方から、混合粒子を散布する。さらに、その上から、不織布Ｃを重ね合わせ、熱プレス処理を行う。熱プレスの際の不織布Bおよび不織布Cの表面温度は、熱可塑性樹脂粒子Aの融点および熱可塑性樹脂粒子Bの融点で、より高い方の融点の３～５０℃、好ましくは５～２０℃高いことが好ましい。５０℃より高い場合、熱可塑性樹脂粒子が溶融しすぎてシート状になり、多層積層濾材の通気性が悪化する。３℃より低い場合は、十分な接着力が得られない。また、１回の熱プレスで加工するため、熱可塑性樹脂粒子Aおよび熱可塑性樹脂粒子Bの融点の差は、０℃～２０℃であることが好ましい。 Next, the nonwoven fabric B is arranged below the nonwoven fabric A in the vertical direction. At this time, the gap between nonwoven fabric A and nonwoven fabric B is preferably 1 cm or more and 20 cm or less. Within this range, the functional particles A pass through the nonwoven fabric A efficiently, and uneven distribution and scattering are less likely to occur. Then, mixed particles are dispersed from above the nonwoven fabric A side. Further, a nonwoven fabric C is overlaid thereon, and heat press processing is performed. The surface temperature of the nonwoven fabric B and the nonwoven fabric C during hot pressing is 3 to 50°C higher than the melting point of the thermoplastic resin particles A and the melting point of the thermoplastic resin particles B, preferably 5 to 20°C higher. is preferred. When the temperature is higher than 50°C, the thermoplastic resin particles are melted too much to form a sheet, and the air permeability of the multi-layered filter medium is deteriorated. If the temperature is lower than 3°C, sufficient adhesion cannot be obtained. In addition, the difference in melting point between thermoplastic resin particles A and thermoplastic resin particles B is preferably 0° C. to 20° C. because processing is performed by one hot press.
また、混合粒子を散布する際に、不織布Ａをバイブレーター等により振動させてもよい。振動を加えることにより、機能性粒子Ａおよびバインダー粒子Ａが不織布Ａをすり抜けて、不織布Ａと不織布Ｂとにより形成される層間により確実に配置することができる。 Further, the nonwoven fabric A may be vibrated by a vibrator or the like when the mixed particles are dispersed. By applying vibration, the functional particles A and the binder particles A pass through the nonwoven fabric A and can be more reliably arranged between the layers formed by the nonwoven fabrics A and B.
この製造方法に用いる製造設備としては、たとえば、ロール間熱プレス法、あるいは、上下ともにフラットな熱ベルトコンベヤー間に挟み込むダブルベルト熱プレス法等が挙げられる。接着圧をかけることなく、より均一な厚み、接着状態となる後者がより好ましい。 The manufacturing equipment used in this manufacturing method includes, for example, a roll-to-roll heat press method, or a double belt heat press method in which the film is sandwiched between two flat heat belt conveyors. The latter is more preferable because it provides a more uniform thickness and adhesion state without application of adhesion pressure.
以下、実施例を用いて本発明をより具体的に説明する。なお、本実施例における評価方法を下記の通りである。 EXAMPLES The present invention will be described in more detail below using examples. In addition, the evaluation method in the present example is as follows.
（１）１０％粒子径（D１０）および５０％粒子径（D５０）
多層積層濾材の不織布を単離し、不織布上の機能性粒子を光学顕微鏡（デジタルマクロスコープ（KEYENCE製 型番VHX-6000））を用いて、視野のサイズ１７００μｍ×１３００μｍを倍率２００倍、解像度１６００ピクセル×１２００ピクセルで観察し、撮影を行う。次に、上記の光学顕微鏡の計測モードにより、粒子をはさむ一定方向の二本の平行性の間隔を計測し機能性粒子の粒子径とする（Ｆｅｒｅｔ径）。上記の操作を、不織布上に存在する機能性粒子のうちから無作為に選出する１００個の機能性粒子ついて行い、機能性粒子の粒子径個数分布を得る。この作業を、不織布層上から無作為に選出した１０点の観測部位について行う。そして、得た粒子径個数分布より、Ｄ１０およびＤ５０はそれぞれ、粒子径分布において粒子径の小さい方から累積して１０個数％および５０個数％になる点における粒子径とする。
(1) 10% particle size (D10) and 50% particle size (D50)
Isolate the non-woven fabric of the multi-layer laminated filter medium, and observe the functional particles on the non-woven fabric with an optical microscope (digital macroscope (manufactured by KEYENCE, model number VHX-6000)). Observe and photograph at 1200 pixels. Next, using the measurement mode of the optical microscope, the distance between two parallel lines sandwiching the particles is measured to determine the particle diameter of the functional particles (Feret diameter). The above operation is performed on 100 functional particles randomly selected from the functional particles present on the nonwoven fabric to obtain the particle size number distribution of the functional particles. This operation is performed on 10 observation sites randomly selected from the nonwoven fabric layer. From the obtained particle size number distribution, D10 and D50 are the particle sizes at the points where the particle size distribution is accumulated from the smaller particle size to 10% by number and 50% by number, respectively.
（２）不織布の最頻値ポアサイズ（μｍ）
濾材の不織布層を単離し、 「多孔質材料自動細孔測定システム Ｐｅｒｍ－Ｐｏｒｏｍｅｔｅｒ」（ＰＭＩ社製、型番CFP-1200AEX）を用いて、バブルポイント法（ＡＳＴＭＦ－３１６－８６に基づく）によって最頻値ポアサイズを算出する。測定サンプル径を２５ｍｍとし、測定液としては、Ｇａｌｗｉｃｋを使用して、細孔径分布測定を行う。得られた細孔径分布曲線において最大ピークとなるポアサイズを最頻値ポアサイズとする。
(2) Mode pore size of nonwoven fabric (μm)
The nonwoven fabric layer of the filter medium is isolated, and the most frequent measurement is performed by the bubble point method (based on ASTM F-316-86) using "Perm-Porometer, a porous material automatic pore measurement system" (manufactured by PMI, model number CFP-1200AEX). Calculate the value pore size. The diameter of the measurement sample is set to 25 mm, and the pore size distribution is measured using Galwick as the measurement liquid. The pore size with the maximum peak in the obtained pore size distribution curve is taken as the mode pore size.
（３）濾材圧力損失（Ｐａ）
平面状の濾材を有効間口面積０．１ｍ２のホルダーにセットし、面風速４．５ｍ／ｍｉｎで鉛直方向に空気を通過させ、フィルター上下流の圧力差を差圧計（山本電気製作所製MANOSTAR W081FN100DV）で測定する。測定は１検体から任意に５箇所をサンプリングして行い、その平均値を用いる。室温２０℃で実施する。
(3) Filter medium pressure loss (Pa)
A flat filter medium is set in a holder with an effective frontage area of 0.1 m 2 , and air is passed vertically at a surface wind speed of 4.5 m/min. ). The measurement is performed by randomly sampling five points from one sample, and the average value is used. It is carried out at room temperature 20°C.
（４）粒子の脱落
１０ｃｍ角のホルダー２個、３０ｃｍ×３０ｃｍの紙、１２ｃｍ×１２ｃｍの不織布を準備する。２個のホルダーで１２ｃｍ角（０，０１ｍ２）の不織布を挟む。機能性粒子を１０ｇ秤量し、不織布の鉛直方向上方から散布する。その後、２個のホルダー毎、１０回往復で振ったときに紙の上に脱落した機能性粒子の質量を測定する。機能性粒子の質量が０．５～０．１ｇの場合、脱落が少ないとし、０．１ｇ未満の場合は、脱落が極めて少ないとする。
(4) Detachment of Particles Two 10 cm square holders, 30 cm×30 cm paper, and 12 cm×12 cm non-woven fabric are prepared. A 12 cm square (0.01 m 2 ) nonwoven fabric is sandwiched between two holders. 10 g of functional particles are weighed and sprinkled vertically above the nonwoven fabric. After that, the mass of the functional particles dropped onto the paper when each two holders were shaken back and forth 10 times is measured. When the mass of the functional particles is 0.5 to 0.1 g, it is considered that there is little shedding, and when it is less than 0.1 g, it is considered that there is very little shedding.
（実施例１）
最頻値ポアサイズが８２μｍのガラス繊維製湿式抄紙不織布の鉛直方向下方に最頻値ポアサイズが２０μｍのＰＰ製エレクトレットメルトブロー不織布を配置し、前記ガラス繊維製湿式抄紙不織布の鉛直方向上方から、混合粒子として、５０％透過粒子径が７５μｍおよび１０％透過粒子径が３０μｍの多孔質シリカ、５０％透過粒子径が７５μｍのポリエチレン接着剤、５０％透過粒子径が３５０μｍの多孔質シリカ、５０％透過粒子径が３５０μｍのポリエチレン接着剤を３：１：３：１の割合で混合したものを１００ｇ／ｍ２散布し、散布後、平均ポアサイズ１２０μｍの湿式抄紙不織布を積層し、加熱により熱可塑性樹脂を溶融させ、濾材を得た。ここで、透過粒子径とは、機能性粒子の粒子径分布をふるい分け法（ＪＩＳ－Ｚ－８８１５：１９９４）によって測定し、機能性粒子の総質量の１０質量％が通過するふるい目の大きさに相当する粒子径を粒子径の１０％透過粒子径とし、機能性粒子の総質量の５０質量％が通過するふるい目の大きさに相当する粒子径を粒子径の５０％透過粒子径とした。濾材の圧力損失は２５Ｐａとなった。
(Example 1)
A PP electret melt-blown nonwoven fabric with a mode pore size of 20 μm is placed vertically below a glass fiber wet-laid papermaking nonwoven fabric with a mode pore size of 82 μm, and from the vertical direction above the glass fiber wet-laid papermaking nonwoven fabric, as mixed particles , porous silica with 50% permeation particle size of 75 μm and 10% permeation particle size of 30 μm, polyethylene adhesive with 50% permeation particle size of 75 μm, porous silica with 50% permeation particle size of 350 μm, 50% permeation particle size 100 g/m 2 of a mixture of polyethylene adhesive with a diameter of 350 µm in a ratio of 3:1:3:1 was sprayed, and after spraying, a wet papermaking nonwoven fabric with an average pore size of 120 µm was laminated, and the thermoplastic resin was melted by heating. , to obtain a filter medium. Here, the permeation particle size is the size of the sieve mesh through which 10% by mass of the total mass of the functional particles passes, measured by a sieving method (JIS-Z-8815: 1994) for the particle size distribution of the functional particles. The particle diameter corresponding to the 10% transmission particle diameter of the particle diameter, and the particle diameter corresponding to the size of the sieve mesh through which 50% by weight of the total mass of the functional particles passes was defined as the 50% transmission particle diameter of the particle diameter. . The pressure loss of the filter medium was 25 Pa.
（実施例２）
機能粒子Aとして、５０％透過粒子径が７５μｍおよび１０％透過粒子径が１５μｍの多孔質シリカを用いること以外は、実施例１と同様に濾材を得た。濾材の圧力損失は２６Ｐａとなった。
(Example 2)
A filter medium was obtained in the same manner as in Example 1, except that porous silica having a 50% transmission particle size of 75 μm and a 10% transmission particle size of 15 μm was used as the functional particles A. The pressure loss of the filter medium was 26 Pa.
（実施例３）
混合粒子として、５０％透過粒子径が７５μｍおよび１０％透過粒子径が３０μｍの多孔質シリカ、５０％透過粒子径が７５μｍのポリエチレン接着剤、５０％透過粒子径が３５０μｍの多孔質シリカ、５０％透過粒子径が３５０μｍのポリエチレン接着剤を３：１：６：２の割合で混合したものを２４０ｇ／ｍ２散布すること以外は、実施例１と同様に濾材を得た。濾材の圧力損失は２８Ｐａとなった。
（実施例４）
混合粒子として、５０％透過粒子径が７５μｍおよび１０％透過粒子径が３０μｍの多孔質シリカ、５０％透過粒子径が７５μｍのポリエチレン接着剤、５０％透過粒子径が３５０μｍの多孔質シリカ、５０％透過粒子径が３５０μｍのポリエチレン接着剤を６：２：３：１の割合で混合したものを２４０ｇ／ｍ２散布すること以外は、実施例１と同様に濾材を得た。濾材の圧力損失は３１Ｐａとなった。
(Example 3)
As mixed particles, porous silica having a 50% permeation particle diameter of 75 μm and 10% permeation particle diameter of 30 μm, 50% permeation particle diameter of 75 μm polyethylene adhesive, 50% permeation particle diameter of 350 μm, 50% A filter medium was obtained in the same manner as in Example 1, except that 240 g/m 2 of a polyethylene adhesive having a permeable particle size of 350 μm mixed in a ratio of 3:1:6:2 was sprayed. The pressure loss of the filter medium was 28 Pa.
(Example 4)
As mixed particles, porous silica having a 50% permeation particle diameter of 75 μm and 10% permeation particle diameter of 30 μm, 50% permeation particle diameter of 75 μm polyethylene adhesive, 50% permeation particle diameter of 350 μm, 50% A filter medium was obtained in the same manner as in Example 1, except that 240 g/m 2 of a polyethylene adhesive having a permeation particle size of 350 μm mixed in a ratio of 6:2:3:1 was sprayed. The pressure loss of the filter medium was 31 Pa.
（比較例１）
最頻値ポアサイズが２０μｍのＰＰ製エレクトレットメルトブロー不織布の鉛直方向上方から、機能性粒子として、５０％透過粒子径が７５μｍおよび１０％透過粒子径が１５μｍの多孔質シリカ、５０％透過粒子径が７５μｍのポリエチレン接着剤を３：１の割合で混合したものを５０ｇ／ｍ２散布し、散布後、平均ポアサイズ４０μｍのガラス繊維製湿式抄紙不織布を積層し、前記ガラス繊維製湿式抄紙不織布上の鉛直方向上方から、機能性粒子として、５０％透過粒子径が３５０μｍの多孔質シリカ、５０％透過粒子径が３５０μｍのポリエチレン接着剤を３：１の割合で混合したものを５０ｇ／ｍ２散布し、散布後、最頻値ポアサイズが１２０μｍの湿式抄紙不織布を積層し、加熱により接着パウダーを溶融させ、濾材を得た。圧力損失は２７Ｐａとなった。
(Comparative example 1)
From the vertical direction above the PP electret melt blown nonwoven fabric with a mode pore size of 20 μm, porous silica with a 50% transmission particle diameter of 75 μm and a 10% transmission particle diameter of 15 μm as functional particles, and a 50% transmission particle diameter of 75 μm. 50 g/m 2 of a polyethylene adhesive mixed at a ratio of 3: 1 is sprayed, and after spraying, a glass fiber wet papermaking nonwoven fabric having an average pore size of 40 μm is laminated, and the glass fiber wet papermaking nonwoven fabric is laminated in the vertical direction. From above, as functional particles, 50 g/m 2 of a mixture of porous silica with a 50% permeation particle size of 350 μm and polyethylene adhesive with a 50% permeation particle size of 350 μm at a ratio of 3: 1 was sprayed. After that, a wet papermaking nonwoven fabric having a mode pore size of 120 μm was laminated, and the adhesive powder was melted by heating to obtain a filter medium. The pressure loss was 27Pa.
（比較例２）
最頻値ポアサイズが４０μｍのガラス繊維製湿式抄紙不織布の鉛直方向下方に最頻値ポアサイズが２０μｍのＰＰ製エレクトレットメルトブロー不織布上を配置し、前記ガラス繊維製湿式抄紙不織布の鉛直方向上方から、機能性粒子として、５０％透過粒子径が７５μｍおよび１０％透過粒子径が１５μｍの多孔質シリカ、５０％透過粒子径が７５μｍのポリエチレン接着剤、５０％透過粒子径が３５０μｍの多孔質シリカ、５０％透過粒子径が３５０μｍのポリエチレン接着剤を３：１：３：１の割合で混合したものを１００ｇ／ｍ２散布し、散布後、最頻値ポアサイズが１２０μｍの湿式抄紙不織布を積層し、加熱により接着パウダーを溶融させ、濾材を得た。濾材の圧力損失は３４Ｐａとなった。
(Comparative example 2)
A PP electret melt blown nonwoven fabric with a mode pore size of 20 μm is placed vertically below a glass fiber wet-laid papermaking nonwoven fabric with a mode pore size of 40 μm, and from the vertical direction above the glass fiber wet-laid papermaking nonwoven fabric, the functional As particles, porous silica with a 50% transmission particle size of 75 μm and a 10% transmission particle size of 15 μm, polyethylene adhesive with a 50% transmission particle size of 75 μm, porous silica with a 50% transmission particle size of 350 μm, and 50% transmission Spray 100 g/m 2 of a mixture of polyethylene adhesive with a particle size of 350 μm at a ratio of 3:1:3:1, and after spraying, laminate a wet papermaking nonwoven fabric with a mode pore size of 120 μm and bond by heating. The powder was melted to obtain a filter medium. The pressure loss of the filter medium was 34 Pa.
（比較例３）
最頻値ポアサイズが８０μｍのガラス繊維製湿式抄紙不織布の鉛直方向下方に最頻値ポアサイズが８０μｍのＰＰ製エレクトレットメルトブロー不織布上を配置し、前記ガラス繊維製湿式抄紙不織布の鉛直方向上方から、機能性粒子として、５０％透過粒子径が７５μｍおよび１０％透過粒子径が１５μｍの多孔質シリカ、５０％透過粒子径が７５μｍのポリエチレン接着剤、５０％透過粒子径が３５０μｍの多孔質シリカ、５０％透過粒子径が３５０μｍのポリエチレン接着剤を３：１：３：１の割合で混合したものを１００ｇ／ｍ２散布し、散布後、最頻値ポアサイズが１２０μｍの湿式抄紙不織布を積層し、加熱により接着パウダーを溶融させ、濾材を得た。機能性粒子の一部が前記ＰＰ製エレクトレットメルトブロー不織布から抜け落ち、濾材の加工はできなかった。
(Comparative Example 3)
A PP electret melt blown nonwoven fabric with a mode pore size of 80 μm is placed vertically below a glass fiber wet-laid papermaking nonwoven fabric with a mode pore size of 80 μm, and from the vertical direction above the glass fiber wet-laid papermaking nonwoven fabric, the functional As particles, porous silica with a 50% transmission particle size of 75 μm and a 10% transmission particle size of 15 μm, polyethylene adhesive with a 50% transmission particle size of 75 μm, porous silica with a 50% transmission particle size of 350 μm, and 50% transmission Spray 100 g/m 2 of a mixture of polyethylene adhesive with a particle size of 350 μm at a ratio of 3:1:3:1, and after spraying, laminate a wet papermaking nonwoven fabric with a mode pore size of 120 μm and bond by heating. The powder was melted to obtain a filter medium. A part of the functional particles fell out from the PP electret melt-blown nonwoven fabric, and the filter medium could not be processed.
得られた濾材から不織布および不織布の層間に配置された粒子を、それぞれ単離した。そして、上記の不織布については、その最頻値ポアサイズを「（２）不織布の最頻値ポアサイズ（μｍ）」の項に記載の方法で測定し、上記の粒子については、そのＤ１０およびＤ５０を「（１）１０％粒子径（D１０）および５０％粒子径（D５０）」の項に記載の方法で測定した。次に、上記の測定で得られた不織布の最頻値ポアサイズおよび粒子のＤ５０を対比し、さらに、「不織布Ｂの最頻値ポアサイズ＜機能性粒子Ａの５０％粒子径（Ｄ５０）＜不織布Ａの最頻値ポアサイズ＜機能性粒子Ｂの５０％粒子径（Ｄ５０）」との関係性を考慮し、不織布Ａ、不織布Ｂ、不織布Ｃ、機能性粒子Ａおよび機能性粒子Ｂを特定した。そして、上記の分析結果を表１にまとめた。また、不織布Bと機能性粒子Aを用いて、粒子の脱落を確認した。
The nonwoven fabric and the particles arranged between the layers of the nonwoven fabric were each isolated from the obtained filter media. Then, the mode pore size of the above nonwoven fabric is measured by the method described in the section "(2) Mode pore size of nonwoven fabric (μm)", and the D10 and D50 of the above particles are measured as " (1) 10% particle size (D10) and 50% particle size (D50)”. Next, the mode pore size of the nonwoven fabric and the D50 of the particles obtained by the above measurement are compared, and further, "the mode pore size of nonwoven fabric B < 50% particle size of functional particles A (D50) < nonwoven fabric A Non-woven fabric A, non-woven fabric B, non-woven fabric C, functional particles A and functional particles B were specified considering the relationship "mode pore size < 50% particle size (D50) of functional particles B". The above analysis results are summarized in Table 1. Also, using the nonwoven fabric B and the functional particles A, it was confirmed that the particles were dropped.
比較例１は、工程数が増えるため、生産性が悪化し、比較例２は、ガラス繊維製湿式抄紙不織布と外層の湿式抄紙不織布の間に、５０％透過粒子径が３５０μｍの多孔質シリカと５０％透過粒子径が７５μｍの多孔質シリカが混在したため、前記５０％透過粒子径が３５０μｍの多孔質シリカの間隙を前記５０％透過粒子径が７５μｍの多孔質シリカが埋めてしまい、通気性が悪化した。また、実施例１は粒子の脱落が非常に少なかったため、生産後の清掃が容易であった。実施例4は、機能性粒子Ａの５０％粒子径（Ｄ５０）が、１００μｍ以下であり、かつ、目付が１００ｇ／ｍ２以上であったため、通気性が実施例３対比悪化した。 In Comparative Example 1, the productivity deteriorated due to an increase in the number of steps. Since the porous silica having a 50% transmission particle diameter of 75 μm was mixed, the gaps between the porous silica having a 50% transmission particle diameter of 350 μm were filled with the porous silica having a 50% transmission particle diameter of 75 μm, resulting in poor air permeability. It got worse. Also, in Example 1, very few particles fell off, so cleaning after production was easy. In Example 4, the 50% particle size (D50) of the functional particles A was 100 μm or less and the basis weight was 100 g/m 2 or more.
本発明の多層積層濾材は生産性に優れ、空気清浄機用フィルターや自動車用キャビンフィルター等に好適に用いることができる。 The multi-layer laminated filter medium of the present invention is excellent in productivity and can be suitably used for filters for air cleaners, cabin filters for automobiles, and the like.
Claims (4)
前記不織布Bと前記不織布Aとで形成される層間に機能性粒子Aが配置されており、
前記不織布Cと前記不織布Aとで形成される層間に機能性粒子Bが配置されており、
下記式（１）を満たす、多層積層濾材。
不織布Ｂの最頻値ポアサイズ＜機能性粒子Ａの５０％粒子径（Ｄ５０）＜不織布Ａの最頻値ポアサイズ＜機能性粒子Ｂの５０％粒子径（Ｄ５０） （１） At least nonwoven fabric B, nonwoven fabric A and nonwoven fabric C are provided in this order,
Functional particles A are arranged between layers formed by the nonwoven fabric B and the nonwoven fabric A,
Functional particles B are arranged between layers formed by the nonwoven fabric C and the nonwoven fabric A,
A multi-layer laminated filter medium that satisfies the following formula (1).
Mode pore size of nonwoven fabric B<50% particle size of functional particles A (D50)<mode pore size of nonwoven fabric A<50% particle size of functional particles B (D50) (1)
不織布Ｂの最頻値ポアサイズ＜機能性粒子Ａの粒子径の１０％粒子径（D１０） （２） The multi-layered filter medium according to claim 1, which satisfies the following formula (2).
Mode pore size of nonwoven fabric B < 10% particle size of functional particle A particle size (D10) (2)
前記機能性粒子Aの目付が、５～１００ｇ／ｍ２である、請求項１または２に記載の多層積層濾材。 The 50% particle diameter (D50) of the functional particles A is 100 μm or less, and
3. The multi-layered filter medium according to claim 1 , wherein said functional particles A have a basis weight of 5 to 100 g/m 2 .
前記不織布Ｂを前記不織布Ａの鉛直方向下方に配置する工程と、
前記不織布A側の上方から、前記機能性粒子Ａと前記機能性粒子Ｂとを含有する混合物を散布する工程とをこの順に有する、多層積層濾材の製造方法。
A method for producing a multilayer laminated filter medium according to any one of claims 1 to 3 ,
A step of arranging the nonwoven fabric B vertically below the nonwoven fabric A;
A method for producing a multi-layer laminated filter medium , comprising a step of spraying a mixture containing the functional particles A and the functional particles B from above the nonwoven fabric A side in this order.
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| JP2002535111A (en) | 1998-08-27 | 2002-10-22 | コスロウ テクノロジーズ コーポレイション | Composite filtration media and fluid filters containing composite filtration media |
| JP2002177717A (en) | 2000-12-14 | 2002-06-25 | Nissan Motor Co Ltd | Dust removal deodorizing filter |
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