JPH1025700A - Paper and filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a paper useful for various filters low in fluid passing resistance and excellent in fine particle trapping ability by conducting a mixed papermaking process for plural kinds of fiber differing in sectional shape from one another. SOLUTION: A pulp slurry is prepared by incorporating wood pulp fibers each flat in sectional shape with 5-50wt.% of e.g. polyester fibers each with H-shaped section differing from the section of the wood pulp fiber, and then subjected to papermaking process, thus obtaining the objective paper high in void content as compared to paper with the same fiber diameter and also small in fine pore size.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【産業上の利用分野】本発明は、例えば空気清浄用フィ
ルター等の各種フィルターに用いられる用紙及びそのフ
ィルターに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to paper used for various filters such as an air purifying filter and the like.

【０００２】[0002]

【従来の技術】例えば自動車分野、機械製造分野、機械
加工分野、工作機分野、船舶分野、下水廃水分野、水処
理分野、集塵機分野等の工業分野全体において各種フィ
ルターが用いられている。例えば燃焼用空気、あるいは
自動車のエンジンの空冷や、室内用等のクーラーの空冷
その他のために取り入れられる空気を清浄にする空気清
浄用フィルター、集塵器に用いられる雰囲気中の塵を濾
し取る集塵器用フィルター、水中の混濁物を濾過する水
濾過用フィルター、油中の混濁物を濾過する油濾過用フ
ィルター等各種フィルターが用いられている。これらフ
ィルターには繊維加工製品が用いられており、その一つ
として繊維を抄き上げた、いわゆる抄紙した用紙も用い
られている。このフィルター用に抄紙した用紙として
は、各種パルプのセルロース繊維を抄き上げた紙、パル
プの繊維に合成繊維やガラス繊維を混合して抄き上げ
た、いわゆる混抄紙等が知られている。これらの紙がフ
ィルターとして用いられるときは、例えば空気清浄用フ
ィルターの場合には、空気の取り入れ口に単層あるいは
多重に重ねられた状態で取り付けられ、吸引器等により
吸引された空気がこれらの単層あるいは重ねられたもの
に当たるようにされる。このようにすると、紙の組織は
繊維が絡み合った構造を有し、繊維と繊維の間に細孔を
有するので、その細孔より大きい空気中の混濁物である
塵は通過を阻まれ、また、細孔より小さい塵は細孔壁に
吸着されて除去される。このようにして取り入れられる
空気はフィルターを通ることにより混濁物を除去される
ことにより清浄化される。このように、フィルターは空
気や水、油等の流体の混濁物を捕らえるが、その性能は
その流体を通過させる抵抗を小さくすること、すなわち
流体を透過し易くすることと、どれだけ小さな混濁物を
捕えることができ、その結果捕集効率を向上できるかと
いうその細孔の細かさ、あるいは細孔壁面積の大きさに
依存する。前者は紙における細孔径や空隙率に大きく依
存し、後者は細孔径や細孔壁面積、厚み等に影響される
ため製品としてはこれらのバランスをとることが重要で
ある。これまで濾紙に用いられている濾過材料としての
用紙は、セルロースパルプのみからなるものと、セルロ
ースパルプ及び合成繊維あるいは無機繊維とを混抄した
ものの２つに大別できる。一般の用紙を製造する抄紙法
では繊維が密に充填され過ぎるためこれを濾紙に用いる
場合には流体の透過性が著しく低くなることから、抄紙
条件に特別の工夫がなされることは勿論であるが、素材
面についても木材パルプの種類とリンターパルプの種
類、それらの混合割合の調節等その用紙を濾紙に使用し
た場合に空隙率を増大させるような試みがいろいろなさ
れている。合成繊維を混抄する目的は、機械的強度の向
上、耐湿強度の向上、耐熱性の向上にある。2. Description of the Related Art For example, various filters are used in the entire industrial fields such as automobile field, machine manufacturing field, machining field, machine tool field, marine field, sewage wastewater field, water treatment field and dust collector field. For example, an air purifying filter that purifies air used for air for combustion or air cooling of a car engine, air cooling of a cooler for indoor use, etc., a filter that filters out dust in the atmosphere used for a dust collector. Various filters such as a dust filter, a water filtration filter for filtering turbid substances in water, and an oil filtration filter for filtering turbid substances in oil are used. Fiber processed products are used for these filters, and as one of them, so-called paper-made paper made of fibers is used. As the paper made for the filter, paper made of cellulose fibers of various pulp and so-called mixed paper made by mixing pulp fibers with synthetic fibers or glass fibers are known. When these papers are used as filters, for example, in the case of an air purifying filter, they are attached to the air intake in a single-layer or multi-layered state, and the air sucked by a suction device or the like is used for these papers. It can be a single layer or a stack. In this way, the paper tissue has a structure in which the fibers are intertwined and has pores between the fibers, so that dust, which is a turbid substance in the air larger than the pores, is blocked from passing, and Dust smaller than the pores is adsorbed to the pore walls and removed. The air thus taken in is cleaned by removing turbidity by passing through a filter. In this way, the filter captures the turbidity of a fluid such as air, water, oil, etc., but its performance is to reduce the resistance that allows the fluid to pass through, that is, to facilitate the permeation of the fluid, and how small the turbidity is. Depending on the fineness of the pores or the size of the pore wall area as to whether the trapping efficiency can be improved as a result. The former greatly depends on the pore diameter and porosity of the paper, and the latter is affected by the pore diameter, the pore wall area, the thickness, and the like, so it is important to balance these as a product. Paper as a filtering material used in filter papers so far can be broadly classified into two types: those composed of cellulose pulp alone and those obtained by mixing cellulose pulp with synthetic fibers or inorganic fibers. In the papermaking method for producing general paper, the fibers are too densely packed, so that when used for filter paper, the permeability of the fluid becomes extremely low, so that special contrivances are made to the papermaking conditions. However, various attempts have been made to increase the porosity when the paper is used for filter paper, such as adjusting the type of wood pulp, the type of linter pulp, and the mixing ratio of these materials. The purpose of blending synthetic fibers is to improve mechanical strength, moisture resistance, and heat resistance.

【０００３】[0003]

【発明が解決しようとする課題】しかしながら、混抄紙
の場合、混合する合成繊維としては、断面形状が円形の
ものが使用されているため繊維の充填密度が高くなり易
く、用紙の組織構造を大きく変えるようなことは困難で
あった。また、細孔壁面積を大きくするのも容易ではな
かった。However, in the case of mixed paper, since synthetic fibers to be mixed have a circular cross section, the packing density of the fibers is likely to be high, and the tissue structure of the paper is large. It was difficult to change. Also, it was not easy to increase the pore wall area.

【０００４】本発明の第１の目的は、空隙率が大きく、
かつ細孔壁面積の大きい用紙及びフルターを提供するこ
とにある。本発明の第２の目的は、流体の流通抵抗が小
さくて透過量を増大しかつ微粒子捕捉能力を向上させた
捕集効率の良い用紙及びフィルターを提供することにあ
る。本発明の第３の目的は、機械的強度、耐湿強度、耐
熱性を向上することができる用紙及びフルターを提供す
ることにある。本発明の第４の目的は、安価に得られる
用紙及びフィルターを提供することにある。A first object of the present invention is to provide a high porosity,
Another object of the present invention is to provide a paper and a filter having a large pore wall area. A second object of the present invention is to provide a paper and a filter having a small collection resistance, a high permeation efficiency, a high permeation amount, and a small particle flow resistance. A third object of the present invention is to provide a paper and a filter capable of improving mechanical strength, moisture resistance and heat resistance. A fourth object of the present invention is to provide a paper and a filter which can be obtained at low cost.

【０００５】[0005]

【課題を解決するための手段】本発明は、上記課題を解
決するために、（１）、断面形状が異形の複数の繊維を
含有する混合物から抄紙された用紙を提供するものであ
る。また、本発明は、（２）、断面形状が異形の複数の
繊維はセルロース繊維と断面形状が該セルロース繊維と
は異形の合成繊維であ上記（１）の用紙、（３）、合成
繊維の割合が繊維全体の５ないし５０重量％である上記
（２）の用紙、（４）、上記（１）ないし（３）のいず
れかの用紙から得られるフィルターを提供するものであ
る。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides (1) a paper made from a mixture containing a plurality of fibers having different shapes in cross section. Further, the present invention provides (2) the paper of (1), wherein the plurality of fibers having a different cross-sectional shape is a cellulose fiber and a synthetic fiber having a different cross-sectional shape from the cellulose fiber. Another object of the present invention is to provide a filter obtained from the paper according to the above (2), in which the proportion is 5 to 50% by weight of the whole fiber, and the paper obtained from the paper according to any one of the above (4) and (1) to (3).

【０００６】次に本発明を詳細に説明する。本発明にお
いて、「断面形状が異形の複数の繊維」とは、円形、楕
円形、三角形や四角形等の多角形、Ｈ型、Ｙ型、扁平形
等あらゆる採りえる断面形状の中から選択される異なる
複数の繊維をいう。この繊維には、通常の濾紙の用紙に
用いられている例えば木材パルプ、リンタパルプ等のセ
ルロース繊維、例えばポリエステル系、ポリアミド系
（ナイロン系）、ポリイミド系、ポリエチレンやポリプ
ロピレン等のポリオレフィン系等の合成繊維が挙げられ
る。これらの繊維は１種又は２種以上混合して用いられ
るが、セルロース繊維と合成繊維を含有する混合物を抄
紙すると、機械的強度、耐湿強度、耐熱性等の点で好ま
しい。断面形状が異形の複数の繊維としては、セルロー
ス繊維と断面形状がこれとは異形の合成繊維が好まし
い。セルロース繊維の断面形状は円形、楕円形あるいは
扁平形が多いがその場合にはこれと混合する合成繊維等
はこれら以外の他の形状とすることが好ましい。上記の
繊維としては、ガラス繊維、鉱物繊維、炭素繊維、セル
ロース以外の他の天然繊維等も使用でき、これらも上記
と同様に用いることができる。Next, the present invention will be described in detail. In the present invention, the “plurality of fibers having a different cross-sectional shape” is selected from all possible cross-sectional shapes such as a circle, an ellipse, a polygon such as a triangle and a quadrangle, an H shape, a Y shape, and a flat shape. A plurality of different fibers. Examples of the fibers include cellulose fibers such as wood pulp and linter pulp used for ordinary filter paper, and synthetic fibers such as polyester, polyamide (nylon), polyimide, and polyolefins such as polyethylene and polypropylene. Is mentioned. These fibers may be used alone or as a mixture of two or more kinds. However, it is preferable to make a mixture containing cellulose fibers and synthetic fibers in terms of mechanical strength, moisture resistance, heat resistance and the like. As the plurality of fibers having a different cross-sectional shape, a synthetic fiber having a different cross-sectional shape from a cellulose fiber is preferable. The cross-sectional shape of the cellulose fiber is often circular, elliptical or flat, but in that case, it is preferable that the synthetic fiber or the like mixed therewith has another shape other than these. As the above fibers, glass fibers, mineral fibers, carbon fibers, natural fibers other than cellulose, and the like can be used, and these can be used in the same manner as described above.

【０００７】断面形状の異なる複数の繊維は、断面形状
が異なり、かつその繊維径（繊維の断面の直径）が異な
る場合でも良く、繊維径が同じ又は異なり断面形状が異
なる複数の繊維と断面形状が同じで繊維径の異なる複数
の繊維の混合物でも良い。これらの繊維の混合物が抄紙
されて、同一種類の繊維を原料に用いた紙、異なる種類
の繊維を原料に用いた、いわゆる混抄紙が得られるが、
その厚さとしては例えば６０〜１００ｇ／ｍ² が挙げら
れるがこれに限らない。これらの用紙を得る際の、断面
形状の異なる複数の繊維は、一つの断面形状のものに対
し他のものが５ないし５０重量％混合されることが好ま
しく、例えばセルロース繊維に対してこれと断面形状の
異なる合成繊維を混合する場合が挙げられるが、５％よ
り少ないと空隙率を大きくする効果が少なく、５０重量
％より多いと従来の製造装置を使用した場合に作業性が
低下する。A plurality of fibers having different cross-sectional shapes may have different cross-sectional shapes and different fiber diameters (diameters of the cross-sections of the fibers). However, a mixture of a plurality of fibers having the same but different fiber diameters may be used. A mixture of these fibers is made into a paper, and a paper using the same type of fiber as a raw material, a so-called mixed paper using different types of fiber as a raw material is obtained,
Examples of the thickness include, but are not limited to, 60 to 100 g / m ² . In obtaining these papers, it is preferable that a plurality of fibers having different cross-sectional shapes are mixed with each other in an amount of 5 to 50% by weight based on one cross-sectional shape. A case in which synthetic fibers having different shapes are mixed may be mentioned, but if it is less than 5%, the effect of increasing the porosity is small, and if it is more than 50% by weight, the workability is reduced when a conventional manufacturing apparatus is used.

【０００８】後述の実施例から明らかのように、このよ
うな断面形状の異なる繊維を含有する混合物の抄紙によ
り得られた紙は、断面形状が扁平形、円形で繊維径が同
じ範囲のものの空隙率の７１．１％〜７６．６％に比べ
て、空隙率を約８１％以上約８７％（８０．６％〜８
６．９％）にすることができ、約１０％向上させること
ができ、しかも断面形状が円形で繊維径が同じ範囲のも
のの細孔の孔径２５〜５５μｍに比べて、１６〜４６μ
ｍ（好ましくは１６〜３８μｍ）のように小さくするこ
とができる。このことから、本発明は、「断面形状が異
形の複数の繊維を含有する混合物から抄紙された用紙で
あって、上記断面形状が異形の複数の繊維は断面形状が
円形（又は楕円形又は扁平形）のセルロース繊維と断面
形状が円形（又は楕円形又は扁平形）でない合成繊維で
あり、かつ合成繊維の割合が繊維全体の５ないし５０重
量％である混合物から抄紙され、かつ空隙率が８０％以
上９０％以下とした（少なくとも８０％とした）用紙」
とすることもでき、また、「細孔の孔径を１６〜４６μ
ｍ（又は１６〜３８μｍ）とし、」の限定を加えても良
く、さらに「紙厚が６０〜１００ｇ／ｍ² （又はほぼ１
００ｇ／ｍ² ）」の限定を加えても良い。これら各発明
において細孔、空隙率は後述の実施例の好ましい範囲の
数値に限定することもできる。また、「用紙」は「フィ
ルター用紙」とすることもでき、「フィルター」はこれ
らの用紙、フィルター用紙を用いたものでも良い。As will be apparent from the examples described later, paper obtained by papermaking a mixture containing fibers having different cross-sectional shapes has voids having a flat cross-sectional shape, a circular cross-section and a fiber diameter in the same range. Porosity of about 81% or more and about 87% (80.6% to 86.6%), compared with the porosity of 71.1% to 76.6%.
6.9%), which can be improved by about 10%, and 16 to 46 μm as compared with the pore diameter of 25 to 55 μm of the pore having a circular cross section and the same fiber diameter.
m (preferably 16 to 38 μm). From the above, the present invention relates to “a paper made from a mixture containing a plurality of fibers having a different cross-sectional shape, wherein the plurality of fibers having a different cross-sectional shape have a circular (or elliptical or flat) cross-sectional shape. Paper) from a mixture of cellulose fibers having a cross-sectional shape not being circular (or elliptical or flat) and synthetic fibers having a proportion of 5 to 50% by weight of the whole fibers, and having a porosity of 80. % Or more and 90% or less (at least 80%) paper "
It is also possible to set the pore size to 16 to 46 μm.
m (or 16 to 38 μm) ”, and further,“ the paper thickness is 60 to 100 g / m ² (or almost 1
00g / m ² ) ”. In each of these inventions, the pores and porosity can be limited to numerical values in preferred ranges of the examples described later. The “paper” may be “filter paper”, and the “filter” may be a paper using these papers or filter paper.

【０００９】本発明の用紙には、他の添加剤を加えても
良く、例えば繊維の水中における分散を良くするため
に、全原料繊維に対し、５重量％以下の界面活性剤等の
分散剤を用いても良く、また、紙の強度を増すために全
原料繊維に対し５重量％以下のポリアクリルアミド系樹
脂等の紙力増強剤その他の添加剤を加えても良い。ま
た、耐油性向上、機械的強度向上を目的として使用され
るフェノール樹脂、エポキシ樹脂等を３０重量％を越え
ない範囲で添加することも可能である。本発明の用紙を
製造するには、原料の繊維を水中に分散させた分散液を
通常の抄紙用装置を通常の方法により用いることにより
製造できる。Other additives may be added to the paper of the present invention. For example, in order to improve the dispersion of the fibers in water, a dispersing agent such as a surfactant of 5% by weight or less based on all the raw fibers is used. May be used, and a paper-strength enhancer such as a polyacrylamide-based resin or the like and 5% by weight or less based on all the raw material fibers may be added in order to increase the strength of the paper. It is also possible to add a phenol resin, an epoxy resin or the like used for the purpose of improving oil resistance and mechanical strength in a range not exceeding 30% by weight. In order to produce the paper of the present invention, a dispersion in which fibers of the raw material are dispersed in water can be produced by using a usual papermaking apparatus by a usual method.

【００１０】本発明の用紙は、濾過器のケース等に例え
ば単層又は多重に重ねて収容され、フィルターとして用
いられる。その種類としては、上記の「従来の技術」の
項で述べた、空気清浄用フィルター、集塵器用フィルタ
ー、水濾過用フィルター、油中の混濁油濾過用フィルタ
ーその他が挙げられる。[0010] The paper of the present invention is accommodated in a case of a filter or the like, for example, in a single layer or multiple layers and used as a filter. Examples of the types include the filters for air cleaning, filters for dust collectors, filters for water filtration, filters for filtering turbid oil in oil, and the like described in the above section of "Conventional Technology".

【００１１】[0011]

【発明の実施の形態】詳細は以下の実施例で説明する
が、断面形状の異なる複数の繊維の混合物から得られる
用紙は、特にその断面形状の異なる繊維が繊維全体の５
〜５０重量％含有されている場合には、その繊維全体の
断面形状が同じ場合、特に円形である場合に比べ、充填
密度を低くすることができ、また、細孔壁面積を大きく
することができる。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As will be described in detail in the following examples, paper obtained from a mixture of a plurality of fibers having different cross-sectional shapes is particularly suitable for paper having different cross-sectional shapes.
When the content is about 50% by weight, the packing density can be reduced and the pore wall area can be increased as compared with the case where the cross-sectional shape of the whole fiber is the same, especially when the fiber is circular. it can.

【００１２】[0012]

【実施例】以下に実施例によって本発明をさらに詳細に
説明するが、本発明はこれらに限定されるものではな
い。また、各実施例における部はいずれも重量部であ
る。 実施例１ 木材パルプ（断面形状が扁平の繊維径（長径：２０〜３
０μ、短径：５〜２０μ）のセルロース繊維）９０重量
％と、ポリエステル繊維（断面形状がＨ型で繊維径（Ｈ
の内接円の直径、以下同様）２０〜３０μｍ）１０重量
％を水と混合した混合物を網上に展開させて水分を濾過
する通常の方法により抄紙を行ない、８０℃で乾燥させ
て厚さ１０３ｇ／ｍ² の混抄紙を製造した。この紙につ
いて調べたところ、紙厚０．３３ｍｍ、透気度１５．
９、細孔の孔径１８〜２４μｍ、空隙率８１．５％であ
った。EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. All parts in each example are parts by weight. Example 1 Wood pulp (Fiber diameter of flat cross section (major diameter: 20 to 3)
90% by weight of a cellulose fiber having a fiber diameter of 0 μ and a minor diameter of 5 to 20 μ) and a polyester fiber (having an H-shaped cross section)
The diameter of the inscribed circle of the same, hereinafter the same) 20 to 30 μm) Papermaking is carried out by a usual method of developing a mixture obtained by mixing 10% by weight of water on a net and filtering the water, and drying at 80 ° C. A mixed paper of 103 g / m ² was produced. When this paper was examined, the paper thickness was 0.33 mm and the air permeability was 15.
9, the pore diameter was 18 to 24 μm, and the porosity was 81.5%.

【００１３】なお、透気度とは、ＪＩＳ Ｐ８１３１
「紙及び板紙の透気度試験方法」に準じて行なう測定値
であって、直径１０ｍｍの円形試験片を３００ｃｃの空
気が通過する時間で表示される。また、孔径とは濾紙の
平面に垂直方向から撮影した電子顕微鏡写真を基に見掛
けの孔の大きさを物指しで測定した値である。また、空
隙率は次式で表現される。 空隙率＝〔（ｗ₃ −ｗ₁ ）／（ｗ₃ −ｗ₂ ）〕×１００ ここで、ｗ₁ は濾紙重量、ｗ₂ はブタノール中の濾紙重
量、ｗ₃ はブタノールと濾紙の合計重量である。The air permeability is defined by JIS P8131.
This is a measurement value performed according to the “Test method for air permeability of paper and paperboard”, and is indicated by the time required for 300 cc of air to pass through a circular test piece having a diameter of 10 mm. The pore size is a value obtained by measuring the apparent pore size with an object based on an electron micrograph taken from a direction perpendicular to the plane of the filter paper. The porosity is represented by the following equation. Porosity = [(w ₃ −w ₁ ) / (w ₃ −w ₂ )] × 100 where w ₁ is the weight of filter paper, w ₂ is the weight of filter paper in butanol, and w ₃ is the total weight of butanol and filter paper. is there.

【００１４】比較例１ 実施例１において、ポリエステル繊維として通常のポリ
エステル繊維（断面形状が円形で繊維径２０〜３０μ
ｍ）を用いた以外は同様にして抄紙し、乾燥して１０２
ｇ／ｍ² の紙を得た。この得られた紙について実施例１
と同様に調べたところ、紙厚０．３９ｍｍ、透気度８．
３、孔径２７〜３５μｍ、空隙率７１．３％であった。Comparative Example 1 In Example 1, an ordinary polyester fiber (having a circular cross section and a fiber diameter of 20 to 30 μm) was used as the polyester fiber.
m), except that m) was used.
g / m ² of paper were obtained. Example 1 of the obtained paper
When the paper was examined in the same manner as described above, the paper thickness was 0.39 mm and the air permeability was 8.
3, the pore diameter was 27 to 35 μm, and the porosity was 71.3%.

【００１５】実施例２ 木材パルプ（断面形状が扁平（実施例１と同様）の繊維
径のセルロース繊維）８０重量％と、ポリエステル繊維
（断面形状がＹ型で繊維径２０〜３０μｍ）１０重量％
を水と混合した混合物を網上に展開させて水分を濾過す
る通常の方法により抄紙を行ない、８０℃で乾燥させて
厚さ１０２ｇ／ｍ² の混抄紙を製造した。この得られた
紙について実施例１と同様に調べたところ、紙厚０．３
８ｍｍ、透気度９．８、細孔の孔径２５〜３１μｍ、空
隙率８２．９％であった。Example 2 80% by weight of wood pulp (cellulose fiber having a flat cross-sectional shape (same as in Example 1) fiber diameter) and 10% by weight of polyester fiber (Y-type cross section and fiber diameter of 20 to 30 μm)
Was mixed with water to form a mixed paper having a thickness of 102 g / m ² by developing the mixture on a net and filtering the water by a conventional method of filtering water. When the obtained paper was examined in the same manner as in Example 1, the paper thickness was 0.3.
The diameter was 8 mm, the air permeability was 9.8, the pore diameter was 25 to 31 μm, and the porosity was 82.9%.

【００１６】比較例２ 実施例２において、ポリエステル繊維として通常のポリ
エステル繊維（断面形状が円形で繊維径２０〜３０μ
ｍ）を用いた以外は同様にして抄紙し、乾燥して１０４
ｇ／ｍ² の紙を得た。この得られた紙について実施例１
と同様に調べたところ、紙厚０．３９ｍｍ、透気度６．
９、孔径２８〜３８μｍ、空隙率７６．６％であった。Comparative Example 2 In Example 2, a polyester fiber (polyester fiber having a circular cross section and a fiber diameter of 20 to 30 μm) was used as the polyester fiber.
m), except that m) was used.
g / m ² of paper were obtained. Example 1 of the obtained paper
In the same manner as described above, the paper thickness was 0.39 mm and the air permeability was 6.
9, the pore diameter was 28 to 38 μm, and the porosity was 76.6%.

【００１７】実施例３ 木材パルプ（断面形状が扁平（実施例１と同様）の繊維
径のセルロース繊維）６０重量％と、ナイロン繊維（断
面形状がＹ型で繊維径２０〜３０μｍ）４０重量％を水
と混合した混合物を網上に展開させて水分を濾過する通
常の方法により抄紙を行ない、８０℃で乾燥させて厚さ
１００ｇ／ｍ² の混抄紙を製造した。この得られた紙に
ついて実施例１と同様に調べたところ、紙厚０．４８ｍ
ｍ、透気度４．０、細孔の孔径４１〜４６μｍ、空隙率
８６．９％であった。Example 3 60% by weight of wood pulp (cellulose fiber having a flat cross section and the same fiber diameter as in Example 1) and 40% by weight of nylon fiber (Y type cross section and fiber diameter of 20 to 30 μm) the mixture was mixed with water and developed on the network performs paper making by conventional methods of filtering water to produce a mixed paper having a thickness of 100 g / m ² and dried at 80 ° C.. When the obtained paper was examined in the same manner as in Example 1, the paper thickness was 0.48 m.
m, air permeability 4.0, pore diameter 41 to 46 μm, and porosity 86.9%.

【００１８】比較例３ 実施例３において、ナイロン繊維として通常のナイロン
繊維（断面形状が円形の繊維径２０〜３０μｍ）を用い
た以外は同様にして抄紙し、乾燥して１０５ｇ／ｍ² の
紙を得た。この得られた紙について実施例１と同様に調
べたところ、紙厚０．４９ｍｍ、透気度３．４、孔径４
８〜５５μｍ、空隙率７１．１％であった。Comparative Example 3 Paper was made in the same manner as in Example 3 except that ordinary nylon fibers (fiber diameter having a circular cross section of 20 to 30 μm) were used as the nylon fibers, dried, and dried to give 105 g / m ² paper. I got When the obtained paper was examined in the same manner as in Example 1, the paper thickness was 0.49 mm, the air permeability was 3.4, and the hole diameter was 4
The porosity was 8 to 55 μm and the porosity was 71.1%.

【００１９】実施例４ 木材パルプ（断面形状が扁平（実施例１と同様）の繊維
径のセルロース繊維）９２重量％と、ナイロン繊維（断
面形状がＹ型の繊維径２０〜３０μｍ）８重量％を水と
混合した混合物を網上に展開させて水分を濾過する通常
の方法により抄紙を行ない、８０℃で乾燥させて厚さ１
０２ｇ／ｍ² の混抄紙を製造した。この得られた紙につ
いて実施例１と同様に調べたところ、紙厚０．３４ｍ
ｍ、透気度１５．４、細孔の孔径１３〜２０μｍ、空隙
率８０．６％であった。Example 4 92% by weight of wood pulp (cellulose fiber having a flat cross-sectional shape (same as in Example 1)) and 8% by weight of nylon fiber (Y-type fiber diameter of 20 to 30 μm) Is mixed with water to form a mixture on a net, and paper is formed by a usual method of filtering water, and dried at 80 ° C. to a thickness of 1 μm.
A mixed paper of 02 g / m ² was produced. When the obtained paper was examined in the same manner as in Example 1, the paper thickness was 0.34 m.
m, the air permeability was 15.4, the pore diameter was 13 to 20 μm, and the porosity was 80.6%.

【００２０】参考例１ 木材パルプ（断面形状が扁平（実施例１と同様）の繊維
径のセルロース繊維）９０重量％と、極細ナイロン繊維
（断面形状円形の繊維径０．２〜１μｍ）１０％を水と
混合した混合物を網上に展開させて水分を濾過する通常
の方法により抄紙を行ない、８０℃で乾燥させて厚さ９
９ｇ／ｍ² の混抄紙を製造した。この得られた紙につい
て実施例１と同様に調べたところ、紙厚０．３４ｍｍ、
透気度１５．４、細孔の孔径１２〜１８μｍ、空隙率７
５．３％であった。Reference Example 1 90% by weight of wood pulp (cellulose fiber having a flat cross-section (same as in Example 1) fiber diameter) and 10% of ultra-fine nylon fiber (diameter of circular fiber having a circular cross section of 0.2 to 1 μm) Is mixed with water to form a mixture on a net, and paper is formed by a usual method of filtering water, dried at 80 ° C., and dried to a thickness of 9 mm.
A mixed paper of 9 g / m ² was produced. When the obtained paper was examined in the same manner as in Example 1, the paper thickness was 0.34 mm,
Air permeability 15.4, pore diameter 12 to 18 μm, porosity 7
It was 5.3%.

【００２１】上記実施例１、２と比較例１、２の結果か
ら、孔径を小さくでき、また空隙率を大きくでき、した
がって細孔表面積を増大できることが窺われる。共に微
粒子捕捉に有利である。また、実施例３と比較例３の結
果から、透気度及び孔径を似た領域に合わせた場合でも
空隙率には大きな差が生じており、実施例の場合には細
孔表面積が大きいことが窺われる。これは微粒子捕捉に
有利である。また、実施例４と参考例１の結果から、合
成繊維混合比を調節することにより極細繊維混抄紙に似
た孔径、空隙率を得ることができことがわかる。なお、
合成繊維の断面形状Ｈ型、Ｙ型は繊維を溶融紡糸すると
き、その金型の断面形状によりその形状にすることがで
きる。極細繊維は断面形状が円形の繊維を縦割りして細
くするのでその分コスト高になる。The results of Examples 1 and 2 and Comparative Examples 1 and 2 suggest that the pore diameter can be reduced, the porosity can be increased, and the pore surface area can be increased. Both are advantageous for capturing fine particles. Also, from the results of Example 3 and Comparative Example 3, there is a large difference in the porosity even when the air permeability and the pore diameter are adjusted to similar regions, and in the case of the example, the pore surface area is large. Is seen. This is advantageous for capturing fine particles. Further, from the results of Example 4 and Reference Example 1, it can be seen that by adjusting the mixing ratio of the synthetic fibers, it is possible to obtain a pore size and a porosity similar to that of the ultrafine fiber mixed paper. In addition,
The cross-sectional shapes H and Y of the synthetic fibers can be formed by melt-spinning the fibers depending on the cross-sectional shape of the mold. The extra fine fiber is made by dividing the fiber having a circular cross section vertically and making it thinner, so that the cost becomes higher accordingly.

【００２２】[0022]

【発明の効果】本発明によれば、断面形状が異なる複数
の繊維を含有する混合物を抄紙して得られる用紙を提供
できるので、その用紙の空隙率を大きく、かつ細孔の孔
径を小さく、細孔壁面積を大きくでき、流体の流通抵抗
を小さくてその透過量を増大しかつ微粒子捕捉能力を向
上させて捕集効率の良い用紙及びフィルターを提供する
ことができる。また、合成繊維を混抄させると機械的強
度、耐湿強度、耐熱性を向上することができる用紙及び
フルターを提供することができる。また、極細繊維を混
抄する場合に比べ、安価で空隙率、細孔の性能がそれと
同等又はそれ以上の用紙及びフィルターを提供すること
ができる。According to the present invention, it is possible to provide a paper obtained by making a mixture containing a plurality of fibers having different cross-sectional shapes, so that the porosity of the paper is large and the pore diameter of the pores is small. The pore wall area can be increased, the flow resistance of the fluid can be reduced, the permeation amount can be increased, and the capability of capturing fine particles can be improved, so that a paper and a filter having high collection efficiency can be provided. Further, it is possible to provide a paper and a filter capable of improving mechanical strength, moisture resistance strength and heat resistance when mixed with synthetic fibers. Further, compared with the case where the ultrafine fibers are mixed, it is possible to provide a paper and a filter which are inexpensive and have the same or higher porosity and pore performance.

Claims (4)

【特許請求の範囲】[Claims] 【請求項１】 断面形状が異形の複数の繊維を含有する
混合物から抄紙された用紙。1. A paper made from a mixture containing a plurality of fibers having irregular cross-sectional shapes. 【請求項２】 断面形状が異形の複数の繊維はセルロー
ス繊維と断面形状が該セルロース繊維とは異形の合成繊
維である請求項１記載の用紙。2. The paper according to claim 1, wherein the plurality of fibers having a different cross-sectional shape are cellulose fibers and synthetic fibers having a different cross-sectional shape from the cellulose fibers. 【請求項３】 合成繊維の割合が繊維全体の５ないし５
０重量％である請求項２記載の用紙。3. The ratio of the synthetic fibers is 5 to 5 of the whole fibers.
The paper according to claim 2, which is 0% by weight. 【請求項４】 請求項１ないし３のいずれかに記載され
た用紙から得られるフィルター。4. A filter obtained from the paper according to claim 1.