JP4132354B2 - Novel sulfur-containing atomic group-introducing porous body, method for introducing sulfur-containing atomic group to the entire surface of the porous body, and battery separator - Google Patents

Description

【００７６】
【実施例２〜１０】
放電処理の際に存在させる気体の種類を変化させて各種の実験を行った。
（１）被処理体及び処理条件
被処理体としては、ポリエチレン／ポリプロピレン１７分割繊維からなる湿式法により形成した繊維ウエブを、水流絡合処理し、更に、融着処理によりポリエチレン極細繊維を融着させた不織布（厚さ＝０．２５ｍｍ）を用いた。
イオウ含有原子団導入処理は、II型電極対−片面接触型配置（２−II）により実施した。電極として平板状ステンレススチール電極（大きさ＝１５０ｍｍ×２１０ｍｍ）を使用し、誘電体層としてポリテトラフルオロエチレン（ＰＴＦＥ）膜（厚さ＝０．２６ｍｍ）を用いた。対向表面側にＰＴＦＥ膜を担持する両電極の間に、一方のＰＴＦＥ膜と接触し、もう一方のＰＴＦＥ膜からの距離が０．５ｍｍとなるように、前記不織布を配置した。
印加したパルス電圧は、図５に示す波形を有するパルス電圧（電圧＝１０ＫＶｐ，ピーク電流密度＝４４０ｍＡ／ｃｍ²，周波数＝１２５Ｈｚ，立ち上がり時間＝２００ｎ秒）である。
【００７７】
（２）処理手順
具体的な処理手順は以下のとおりである。
真空デシケータ内に電極及び不織布をセットした後、ロータリーポンプで減圧した。ガス混合器で３回、デシケータ内を図７に示す混合ガスで置換した後、図７に示す混合ガスを１気圧まで導入した。前記のパルス電圧を５分間印加して放電処理を実施した。続いて、前記の混合ガスを脱気し、空気を導入した。不織布を取り出し、水洗してから風乾した。
【００７８】
【比較例２】
放電処理の際に存在させる気体を、６．５容量％−ＳＯ₂／９３．５容量％−Ｈｅガスとすること以外は、前記実施例２〜１０と同じ操作を繰り返した。
【００７９】
【比較例３】
１００％Ｈｅガス中で放電処理を行った後、デシケータ内を酸素ガスで置換し、その中に不織布を１５分間放置し、その後デシケータ内に６．５容量％−ＳＯ₂／９３．５容量％−Ｈｅを１気圧まで導入し、その中に５分間放置したこと以外は、前記実施例２〜１０と同じ操作を繰り返した。
【００８０】
【比較例４】
被処理体としては、実施例２〜１０で用いた不織布と同じものを用いた。前記不織布を、濃度１５％の発煙硫酸浴（温度６０℃）に２分間浸漬してスルホン化した後、出力１５００Ｗで６０秒間（単位面積当たりの負荷エネルギー＝１０．２４Ｊ／ｃｍ²）コロナ放電処理した。
【００８１】
【物性評価】
（１）処理不織布の全体Ｓ／Ｃ比
処理不織布の全体Ｓ／Ｃ比を、以下の手順で測定した。
ＮａＨＣＯ₃（８４ｍｇ）を純水（１００ｍｌ）に溶かし、３０％Ｈ₂Ｏ₂水溶液（１ｍｌ）を加えて吸収液を調製した。この吸収液（５ｍｌ）を、燃焼フラスコ（浜田理科製，ＦＨＯ−Ａ型，５００ｍｌ）内に入れ、燃焼フラスコの内壁を前記吸収液でよく濡らした。
処理不織布から試料（約２０ｍｇ）を精秤し、無灰濾紙に包み、燃焼フラスコ内の白金籠にセットした後、燃焼フラスコ内を酸素で充満させた。白金籠に通電し、試料を燃焼させた。試料が燃焼された後、燃焼フラスコをよく振ってから、１０分間放置した。燃焼フラスコの注液部に純水１０ｍｌを入れ、この純水により内壁を洗浄し、数分間放置した。燃焼フラスコ内の吸収液をメスフラスコを使用し、純水で５０ｍｌに希釈し、試験液とした。
イオンクロマトグラフィー（ＤＩＯＮＥＸ社，２０００ｉ／ＳＰ）を用い、試験液のＳＯ₄ ^2-の濃度を測定した。なお、ＳＯ₄ ^2-標準液を用いて校正を行った。
全体Ｓ／Ｃは次の式から算出した。

なお、前記の式で、Ｗは試料質量（ｇ）であり、ａはＳＯ₄ ^2-濃度（ｍｇ／ｍｌ）であり、ｂはＳＯ₄ ^2-の分子量（すなわち９６）であり、ｃはＣ₃Ｈ₆の分子量（すなわち４２）である。前記の実施例２〜１０及び比較例２〜４では、試料がポリオレフィンからなるので、その試料は、すべてＣ₃Ｈ₆からなるものと仮定して炭素の原子数を算出した。結果を図７に示す。
【００８２】
（２）表面Ｓ／Ｃ比及び表面Ｏ／Ｃ比の測定
Ｘ線光電子分光計（ＪＰＳ−９０１０ＭＸ，日本電子社製）を用いて、次の条件にて測定した。
処理不織布から試料を切り出し、純水で洗浄した後乾燥し、サンプルホルダーに固定した。励起源としてＭｇ−Ｋαを用い、印加電圧値を１０ＫＶとし、ビーム電流値を１０ｍＡとし、そして光電子の脱出角度を９０°として、対象表面における炭素原子（Ｃ_is）のピーク面積、イオウ原子（２Ｐ_3/2）のピーク面積、及び酸素原子（Ｏ_is）のピーク面積をそれぞれ測定し、光イオン化断面積補正を行って、Ｓ／Ｃ比及びＯ／Ｃ比を計算した。結果を図７に示す。
【００８３】
（３）電池容量維持率
電極の集電体として、発泡ニッケル基材を用いたペースト式ニッケル正極（幅＝３３ｍｍ，長さ＝１８２ｍｍ）と、ペースト式水素吸蔵合金負極（メッシュメタル系合金，幅＝３３ｍｍ，長さ＝２４７ｍｍ）とを作成した。次いで、実施例２、実施例３、実施例５、実施例７及び実施例１０、並びに比較例２及び３で調製したスルホン化処理不織布から試料片（幅＝３３ｍｍ，長さ＝４１０ｍｍ）を裁断し、それぞれ前記正極と前記負極との間に挟み、渦巻き状に巻回して、ＳＣ型対応の電極群を作成した。この電極群を外装缶に収納した後、電解液として５Ｎ−水酸化カリウム及び１Ｎ−水酸化リチウムを外装缶に注液し、封缶して円筒型ニッケル−水素電池（容量２０００〜２１００ｍＡｈ）を作成した。次いで、それぞれの円筒型ニッケル−水素電池に対し、２０℃の恒温槽中で充電率０．１Ｃで１２時間（１２０％充電）充電し、終止電圧１ボルトになるまで放電率０．１Ｃで放電することを１サイクルとする充放電を５サイクル実施して、電池を活性化させた。
そして、２０℃の恒温槽中で充電率０．１Ｃで１２時間（１２０％充電）充電し、終止電圧１ボルトになるまで放電率０．１Ｃで放電させて、初期容量（Ａ）を測定した。
次いで、２０℃の恒温槽中で充電率０．１Ｃで１２時間（１２０％充電）充電した後、温度６５℃の恒温室内に５日間放置した。その後、２０℃の恒温槽中で終止電圧が１ボルトになるまで放電率０．１Ｃで放電させて、残存容量（Ｂ）を測定した。これらの結果から、次式により容量維持率を算出した。
容量維持率（％）＝（Ｂ／Ａ）×１００
結果を図７に示す。図７に示すように、全体Ｓ／Ｃ比が２以上であれば、容量維持率により優れていることがわかった。
【００８４】
【発明の効果】
本発明によるイオウ含有原子団導入多孔質体は、高い表面Ｓ／Ｃ比と高い表面Ｏ／Ｃ比とを同時に有しており、高度の親水性が新たに付与されたり、親水性が高度に向上しているだけでなく、その親水性の耐久性の面でも優れており、更には、イオン吸収性、アンモニア吸着、又は生体適合性などが新たに付与されたり向上している。
本発明によるイオウ含有原子団導入方法によれば、大掛かりな装置を用いることなく、大気圧下の放電により高い効率で多孔質体の総表面にイオウ含有原子団を導入することができ、しかも、高濃度の硫酸を含む廃液の処理が不要である。また、多孔質体を構成する材料の表面に主としてイオウ含有原子団が導入されるため、多孔質体の強度の劣化がほとんどみられない。本発明方法によれば、高い表面Ｓ／Ｃ比及び高い表面Ｏ／Ｃ比を示す新規のイオウ含有原子団導入多孔質体を製造することができる。
【００８５】
本発明の電池用セパレータは、表面Ｓ／Ｃ比及び表面Ｏ／Ｃ比が同時に高い数値を示すので、以下の種々の優れた効果を有する。すなわち、本発明の電池用セパレータは、濡れ性が優れている。また、本発明の電池用セパレータは、高度の初期及び長期の親水性が新たに付与されたり、親水性が高度に向上しているだけでなく、その親水性の耐久性の面でも優れており、しかも、耐酸化性にも優れているので、セパレータとしての寿命が長い。更には、本発明の電池用セパレータは、容量保持率が優れているので、自己放電抑制作用が高い。
【図面の簡単な説明】
【図１】本発明方法の種々の態様を模式的に示す説明図である。
【図２】本発明方法の基本的原理を模式的に示す断面図である。
【図３】本発明方法において使用することのできる繰返しパルス波の形状を示す説明図である。
【図４】本発明方法において使用することのできる別の繰返しパルス波の形状を示す説明図である。
【図５】本発明方法において使用することのできる更に別の繰返しパルス波の形状を示す説明図である。
【図６】本発明方法の一態様を模式的に示す斜視図である。
【図７】実施例２〜１０及び比較例２〜４の結果を示す表である。
【符号の説明】
１１・・・多孔質体；２１，２２・・・電極；
４１，４２・・・非多孔質誘電体層；５１・・・交流電源；
６１，６４・・・ガス供給パイプ；６２・・・連結管；
６３，６５・・・ノズル。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel sulfur-containing atomic group-introduced porous body, a method for introducing a sulfur-containing atomic group to the total surface of the porous body, and a battery separator using the sulfur-containing atomic group-introduced porous body.
[0002]
[Prior art]
Conventionally, as one of the methods for introducing a sulfur-containing atomic group into the surface of a porous body, sulfonation treatment is known, and as a method for performing the sulfonation treatment, for example, a method using fuming sulfuric acid, or A method of performing plasma processing by atmospheric pressure glow discharge in a mixed gas atmosphere of a processing gas and a rare gas has been known. Using these methods, the surface of the porous body is sulfonated [that is, sulfonic acid groups (SO_ThreeBy introducing H), it is possible to impart hydrophilicity to the porous body or improve hydrophilicity. The degree of sulfonation in the obtained treated product is correlated with the ratio of the number of sulfur atoms (S) to the number of carbon atoms (C) on the treated surface (hereinafter referred to as surface S / C ratio), The higher the degree of sulfonation, the higher the surface S / C ratio.
[0003]
According to the method using fuming sulfuric acid, a sulfonic acid group can be introduced with high efficiency, and a treated body having a high surface S / C ratio can be obtained. However, in the treated body sulfonated by this method, the ratio of the number of oxygen atoms (O) to the number of carbon atoms (C) on the treated surface, which is an index indicating that a carboxyl group or the like has been introduced ( Hereinafter, the surface O / C ratio) tends to be low. The surface O / C ratio correlates with wettability, and those having a low surface O / C ratio have poor wettability. For example, when a treated body sulfonated by this method is used as a battery separator, it is necessary to perform another treatment (for example, application of a surfactant) in order to improve wettability.
Moreover, the method using fuming sulfuric acid requires a large-scale apparatus for washing unreacted fuming sulfuric acid, and has a problem of treating a large amount of waste liquid containing high-concentration sulfuric acid. Furthermore, there was a problem that the strength of the porous body was deteriorated.
[0004]
On the other hand, a method of performing plasma processing by atmospheric pressure glow discharge in a mixed gas atmosphere of processing gas and rare gas is disclosed in, for example, Japanese Patent Laid-Open No. 9-85026. In the publication, a solid dielectric is disposed on at least one facing surface of a pair of electrodes facing each other, a three-dimensional network porous body is disposed between these electrodes, and a mixed gas of a processing gas and a rare gas is formed. Disclosed is a treatment method characterized by performing a discharge plasma treatment on the porous body under a pressure in the vicinity of atmospheric pressure. In this method, when the concentration of the processing gas in the mixed gas exceeds 10% by volume of the rare gas (that is, the concentration of the processing gas in the mixed gas exceeds 9.09% by volume), a voltage is applied. However, since it is difficult to generate uniform discharge plasma, the concentration of the processing gas in the mixed gas is preferably 0.01 to 9.09% by volume, and sulfur dioxide (processing gas) 0.5% by volume. It is disclosed in the above-mentioned publication that the discharge plasma treatment was actually performed in a sulfur dioxide / helium mixed gas containing. In the above publication, sulfur dioxide, sulfur trioxide, oxygen, nitrogen, or the like is exemplified as the processing gas.
[0005]
As apparent from the disclosure in the above publication, in the method using atmospheric pressure glow discharge, it is necessary to apply a voltage in the presence of a rare gas exceeding 90% by volume in order to generate uniform discharge plasma. Therefore, a sulfonated body having a high surface S / C ratio and a high surface O / C ratio at the same time, which cannot increase the concentration of the processing gas in the mixed gas beyond the limit value, has been heretofore known at all. There wasn't.
[0006]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a novel sulfur-containing atomic group-introduced porous body having a high surface S / C ratio and a high surface O / C ratio at the same time. In addition, another problem of the present invention is that it does not require a large-scale apparatus or a large amount of waste liquid containing high-concentration sulfuric acid, and sulfur-containing atomic groups are efficiently transferred to the entire surface of the porous body by discharge under atmospheric pressure. It is to provide means that can be introduced. Another object of the present invention is to provide a battery separator having a high surface S / C ratio and a high surface O / C ratio at the same time.
[0007]
[Means for Solving the Problems]
  The above problem is in accordance with the present invention,
Made of organic materialsA sulfur-containing atomic group-introduced porous body in which a sulfur-containing atomic group is introduced into at least a part of the total surface of the porous body,
The ratio (S / C) of the number of sulfur atoms (S) to the number of carbon atoms (C) measured by an X-ray photoelectron spectrometer on the surface into which the sulfur-containing atomic group was introduced was 7 × 10.^-4That's it,
The ratio (O / C) of the number of oxygen atoms (O) to the number of carbon atoms (C) measured by an X-ray photoelectron spectrometer on the surface introduced with the sulfur-containing atomic group is 0.2 or more,
The ratio (S / C) of the number of sulfur atoms (S) to the number of carbon atoms (C) in the entire sulfur-containing atomic group-introduced porous body is 1 × 10^-3That's it
This can be achieved by the sulfur-containing atomic group-introduced porous material.
[0008]
  The present invention also provides:Made of organic materialsA sulfur-containing atomic group-introduced nonwoven fabric in which a sulfur-containing atomic group is introduced into at least a part of the total surface of the nonwoven fabric,
The ratio (S / C) of the number of sulfur atoms (S) to the number of carbon atoms (C) measured by an X-ray photoelectron spectrometer on the surface into which the sulfur-containing atomic group was introduced was 7 × 10.^-4That's it,
The ratio (O / C) of the number of oxygen atoms (O) to the number of carbon atoms (C) measured by an X-ray photoelectron spectrometer on the surface introduced with the sulfur-containing atomic group is 0.2 or more,
The ratio (S / C) of the number of sulfur atoms (S) to the number of carbon atoms (C) in the entire sulfur-containing atomic group-introduced porous body is 1 × 10^-3That's it
The present invention also relates to a battery separator made of a sulfur-containing atomic group-introduced nonwoven fabric.
[0009]
  Furthermore, the present invention provides a dielectric layer on the opposing surface side of at least one of the electrodes, and a pair of electrodes arranged opposite to each other.Made of organic materialsA porous body is disposed, and a voltage is applied between the electrodes in the presence of 10% by volume or more of a sulfur-containing compound gas with respect to the total volume of the surface treatment gas and under atmospheric pressure, The present invention also relates to a method for introducing a sulfur-containing atomic group into at least a part of the total surface of the porous body, which is characterized by generating a discharge.
[0010]
  Furthermore, the present invention provides a dielectric layer on the opposing surface side of at least one of the electrodes between a pair of electrodes arranged opposite to each other.Made of organic materialsA porous body is disposed between the electrodes in the presence of 10% by volume or more of a sulfur-containing compound gas and in the presence of oxygen gas and at atmospheric pressure with respect to the total volume of the surface treatment gas. The present invention also relates to a method for introducing a sulfur-containing atomic group into at least a part of the total surface of a porous body, wherein a voltage is applied to generate a discharge.
[0011]
  Furthermore, according to the present invention, the pair of electrodes are not directly in contact with each other between the pair of electrodes arranged to face each other by providing a dielectric layer on each facing surface side. So that the outer surface is in direct contact withMade of organic materialsA porous body is disposed, and a voltage is applied between the electrodes in the presence of 10% by volume or more of a sulfur-containing compound gas with respect to the total volume of the surface treatment gas and under atmospheric pressure, The present invention also relates to a method for introducing a sulfur-containing atomic group into at least a part of the total surface of the porous body, wherein discharge is generated in the internal space of the porous body sandwiched between both electrodes.
[0012]
In this specification, the “total surface” is a concept including both the outer surface of the porous body to be treated and the inner surface of the porous body. “Outer surface” means the surface of a porous body in contact with a virtual solid body having a smooth surface that circumscribes the porous body. Further, the “inner surface” means the entire surface of all the internal voids included in the virtual solid of the porous body. Therefore, the inner surface is the surface of each cell (cell) in the foam-type porous body, and is the surface of a concave structure (for example, a dent or a groove) or a through-hole in the film-type porous body. In the porous material, the surface of the internal space formed by the constituent fibers, that is, the entire surface of each constituent fiber is included.
[0013]
In the present specification, the “sulfur-containing atomic group” is newly introduced into a treated body obtained by treating a porous body to be treated (hereinafter sometimes referred to as an object to be treated) by the method of the present invention. Means an atomic group containing a sulfur atom. The presence state of the sulfur-containing atomic group or the bonding state with the porous body is not particularly limited. For example, the sulfur-containing atomic group is chemically and / or physically bonded to the porous body. Atoms, functional groups, bridging groups, or molecules are included.
The sulfur-containing atomic group introduced into the surface of the treated body (that is, the sulfur-containing atomic group-introduced porous body) can be determined by X-ray photoelectron spectroscopy.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
In the sulfur-containing atomic group-introduced porous material according to the present invention, the ratio of the number of sulfur atoms (S) to the number of carbon atoms (C) measured by an X-ray photoelectron spectrometer on the surface into which the sulfur-containing atomic group has been introduced. (Ie, the surface S / C ratio) is 7 × 10^-FourThe ratio of the number of oxygen atoms (O) to the number of carbon atoms (C) (that is, the surface O / C ratio) measured by the X-ray photoelectron spectrometer is 0.2 or more. Thus, no technique for obtaining a sulfur-containing atomic group-introduced porous body having a high surface S / C ratio and a high surface O / C ratio at the same time has been known so far. The introduced porous body is not known at all.
[0015]
In the sulfur-containing atomic group-introduced porous material according to the present invention, the surface S / C ratio is preferably 6 × 10.^-2Or more, more preferably 7 × 10.^-2That's it. When the method of the present invention described later is used, a surface S / C ratio of up to about 0.8 can be obtained. In the sulfur-containing atomic group-introduced porous material according to the present invention, the surface O / C ratio is preferably 0.25 or more. In the case of sulfonation by a conventional method using fuming sulfuric acid or a conventional method using glow discharge, the surface O / C ratio is usually less than 0.2. When the method of the present invention described later is used, a surface O / C ratio of up to about 3 can be obtained.
The S / C ratio of the entire porous body into which the sulfur-containing atomic group has been introduced (hereinafter sometimes referred to as the total S / C ratio) is 1 × 10^-3When it becomes above, since sulfur content increases, there exists an effect which physical properties, such as ion exchange capacity, ion absorptivity, ammonia absorptivity, or biocompatibility, improve, for example. In particular, the overall S / C ratio is 1.5 × 10^-3When the above sulfur-containing atomic group-introduced nonwoven fabric is used as a battery separator, the self-discharge suppressing action of the battery is improved. The overall S / C ratio is 2 × 10^-3When the above-described sulfur-containing atomic group-introduced nonwoven fabric is used as a battery separator, the self-discharge suppressing action of the battery is further improved. On the other hand, in the glow discharge according to the conventional method, the S / C ratio of the entire sulfonated body is 1 × 10.^-3Is less than.
[0016]
The sulfur-containing atomic group-introduced porous body according to the present invention is a porous body consisting essentially of an organic polymer material (especially an organic synthetic polymer material) substantially free of sulfur atoms and oxygen atoms in the structural unit. In the case where the sulfur-containing atomic group is introduced, the overall S / C ratio is 0.05 or less.
The total S / C ratio can be obtained, for example, by determining the sulfur content of the porous body using organic elemental analysis or an oxygen combustion flask method, and determining the total S / C ratio from the composition and weight of the porous body. The carbon content can also be measured by organic elemental analysis.
[0017]
In the preferred sulfur-containing atomic group-introduced porous material according to the present invention, the ratio (A / B) of the surface S / C (A) to the total S / C ratio (B) is 15 or more, more preferably 20 or more. Most preferably, it is 25 or more. The large ratio (A / B) of the surface S / C ratio (A) to the total S / C ratio (B) means that the sulfur-containing atomic groups are localized on the surface side of the material constituting the porous body. It means that the tendency is large, that is, the sulfur-containing atomic group is not introduced deep inside the material constituting the porous body, and therefore the sulfur-containing atomic group-introduced porous body is excellent in strength. Means. In contrast, when sulfonated by a conventional method using fuming sulfuric acid, the sulfur-containing atomic group penetrates deeply into the material constituting the porous body, so the strength of the sulfur-containing atomic group-introduced porous body decreases. To do. When the method of the present invention described later is used, a treated body having an A / B ratio of up to about 100 can be obtained.
[0018]
The surface S / C ratio is measured by, for example, measuring the peak area of carbon atoms on the target surface and the peak area of sulfur atoms on the target surface using X-ray photoelectron spectroscopy, and correcting the photoionization cross section. Can be obtained by adding The surface O / C ratio is also measured by measuring the peak area of carbon atoms on the target surface and the peak area of oxygen atoms on the target surface using X-ray photoelectron spectroscopy, and correcting the photoionization cross section. Can be obtained by adding In order to remove substances (for example, surfactants) existing on the surface of the measurement object and affecting the surface S / C ratio and / or the surface O / C ratio, the measurement object is washed in advance. Perform the analysis.
[0019]
The sulfur-containing atomic group-introduced porous body according to the present invention is, for example, the detection of the hydrophilic treatment, the surface S / C ratio and the surface O on the treated surface of the treated body that has been found to have been subjected to the hydrophilic treatment. It can be identified by measuring the / C ratio. For example, a case where a wetting index is used for detection of a hydrophilic treatment is shown below.
[0020]
(1) A certain porous material sample is analyzed using means such as an infrared analyzer, and the constituent material of the portion not belonging to the total surface is determined. As the portion not belonging to the total surface, when the sample is a film-type porous body or a foam-type porous body, for example, a solid body portion can be mentioned, and the sample is a fiber-type porous body. In the case of a solid body, for example, an internal portion of a constituent fiber can be exemplified. The wetting index of the porous body made of the determined constituent material is expressed as “wetting test method for polyethylene and polypropylene films” (JIS K 6768).^-1977) In the case of a plurality of components, the wetting index of the component having the smaller wetting index is determined. An indicator is selected that can wet and color the material having this wetting index.
[0021]
(2) When the sample is dipped in a wet index indicator solution (containing a colorant) determined in the step (1) and then pulled up, depending on the state of the sample surface, the color state of the sample surface is Applies to any of the following states (a) to (c):
(A) A colored portion (non-processed region) and a non-colored portion appear. It can be seen that the non-colored portion has been subjected to a hydrophobic treatment. In this case, it can be seen that this sample has not been subjected to a hydrophilic treatment.
(B) The entire sample is not colored. It can be seen that the entire sample has been hydrophobized. In this case, it can be seen that this sample has not been subjected to a hydrophilic treatment.
(C) The entire sample is colored. This sample can be considered to be partially or wholly hydrophilized and not subjected to surface treatment. In this case, the next step (3) is subsequently performed.
[0022]
(3) The sample is dipped in an indicator solution having a higher wetting index than the indicator used in the step (2) and then pulled up. As the indicator, it is preferable to first use an indicator having a slightly higher wetting index than that used in the step (2), and successively use an indicator having a higher wetting index and repeat the above operation. The surface condition of the sample applies to any of the following states (d) to (f):
(D) When an indicator having a slightly higher wetting index than that used in the step (2) is used, the entire sample is not colored. It can be seen that this sample is not subjected to any surface treatment.
(E) When an indicator having a slightly higher wetting index than the indicator used in the step (2) is used, a non-colored portion (non-treated region) and a colored portion appear. It can be seen that the colored portion is hydrophilized. In this case, subsequently, step (4) described later is performed.
(F) When an indicator having a higher wetting index than the indicator used in the step (2) is sequentially used, the entire sample is colored up to a certain wetting index, and the wetting index is slightly higher than the wetting index. When the indicator is used, the entire sample is not colored. It can be seen that the entire sample is hydrophilized. In this case, the next step (4) is subsequently performed.
The presence or absence of the hydrophilization treatment can be detected by the above steps (1) to (3). When a hydrophilic treatment is performed, in order to determine whether or not the treated body is the sulfur-containing atomic group-introduced porous body of the present invention, the surface S / C ratio on the treated surface of the treated body and The surface O / C ratio is measured.
[0023]
(4) The surface S / C ratio and the surface O / C ratio of the processing region are determined by the X-ray photoelectron spectroscopy. Surface S / C ratio is 7 × 10^-FourIf the surface O / C ratio is 0.2 or more, the sample is a sulfur-containing atomic group-introduced porous material according to the present invention.
[0024]
The sulfur-containing atomic group-introduced porous body according to the present invention can be produced by introducing a sulfur-containing atomic group into the porous body by various methods found by the present inventors.
In the method for introducing a sulfur-containing atomic group according to the present invention, discharge is carried out in the presence of a gaseous sulfur-containing compound. Examples of the sulfur-containing compound include sulfur oxide and hydrogen sulfide (H₂S). Examples of the sulfur oxide include sulfur monoxide (SO) and sulfur dioxide (SO).₂), Sulfur trioxide (SO_Three), Disulfur trioxide (S₂O_Three) Or sulfur heptoxide (S₂O₇). In the method of the present invention, each of the above compounds can be used alone or in combination. In terms of being able to generate a stable discharge, the formula SO_x(Wherein x is an integer of 1 to 3), sulfur oxide represented by₂It is more preferable to use
[0025]
The method for introducing a sulfur-containing atomic group according to the present invention can be carried out in the presence or absence of a rare gas. In other words, the rare gas required to stably generate a discharge in the conventional atmospheric pressure glow discharge is not necessarily required, and the method of the present invention can generate a stable discharge even in the absence of the rare gas. It is. In the present specification, “rare gas” means a group 0 element of the periodic table, specifically, six elements of helium, neon, argon, krypton, xenon, and radon.
The method for introducing a sulfur-containing atomic group according to the present invention can be carried out at atmospheric pressure and in the presence of a sulfur-containing compound gas, in an open system, that is, generally in the presence of air, or It can also be carried out at atmospheric pressure in a closed system, for example an airtight container.
[0026]
  In one sulfur-containing atomic group introduction method according to the present invention, the concentration of the sulfur-containing compound gas is relative to the total volume of the surface treatment gas.1The discharge is performed in the range of 0% by volume or more, more preferably in the range of 20 to 90% by volume, and most preferably in the range of 25 to 80% by volume.TheIf the concentration of the sulfur-containing compound gas is less than 10% by volume with respect to the total volume of the surface treatment gas, the introduction efficiency may be low or the expected introduction effect may not be obtained.
[0027]
  In another sulfur-containing atomic group introduction method according to the present invention, in addition to the sulfur-containing compound gas as the sulfur-containing atomic group introduction gas, as a diluent gas, other gases such as air, nitrogen, oxygen, or a rare gas, Or discharge in the presence of a combination thereof (for example, a mixed gas of a rare gas and oxygen), preferably in the presence of oxygen, and more preferably in an atmosphere of substantially a combination of a sulfur-containing compound gas and oxygen alone. Can be implemented. In the present specification, a mixed gas of a sulfur-containing compound gas that is a gas for introducing a sulfur-containing atomic group and a dilution gas may be referred to as a “surface treatment gas”. The concentration of the dilution gas is not particularly limited as long as the concentration of the sulfur-containing compound gas is within an appropriate range, and can be determined as appropriate. Even when discharge is performed in the presence of sulfur-containing compound gas and oxygen, the concentration of the sulfur-containing compound gas is relative to the total capacity of the surface treatment gas.1It is 0 volume% or more, More preferably, it is 20-90 volume%, Most preferably, it is 25-80 volume%. Even when discharge is performed in the coexistence of sulfur-containing compound gas and oxygen alone, the concentration of the sulfur-containing compound gas is relative to the total capacity of the surface treatment gas.1It is 0 volume% or more, More preferably, it is 20-90 volume%, Most preferably, it is 25-80 volume%.
[0028]
In the method for introducing a sulfur-containing atomic group according to the present invention, a porous body is disposed between a pair of electrodes disposed opposite to each other by providing a dielectric layer on the facing surface side of at least one of the electrodes. Since at least one of the pair of electrodes carries the dielectric layer, the electrode used in the method for introducing a sulfur-containing atomic group according to the present invention includes:
(I) a mode in which the pair of electrodes includes an electrode provided with a dielectric layer on the opposing surface side and an electrode not carrying the dielectric layer (hereinafter referred to as an I-type electrode pair);
(II) A mode in which both of the pair of electrodes are electrodes provided with a dielectric layer on the opposite surface side (hereinafter referred to as a type II electrode pair)
Is included.
[0029]
The porous body disposed between the pair of electrodes may be in contact with the electrode surface of the electrode or the dielectric layer, or may not be in contact. Therefore, as an aspect of the arrangement of the pair of electrodes and the porous body,
(1) A mode in which a pair of electrodes (or dielectric layers) and a porous body are arranged in a non-contact state (hereinafter referred to as non-contact type arrangement),
(2) One outer surface of the porous body is in contact with one of the pair of electrodes (that is, the electrode surface of the electrode not carrying the dielectric layer or the dielectric layer), and the porous body A mode in which a pair of electrodes and a porous body are arranged in a state where one outer surface is not in contact with the other electrode (that is, the electrode surface of the electrode not carrying the dielectric layer or the dielectric layer) ( Hereinafter referred to as single-sided contact arrangement), or
(3) A pair of electrodes and a porous material in a state where both outer surfaces of the porous body are in contact with both of the pair of electrodes (that is, the electrode surface of the electrode not carrying the dielectric layer or the dielectric layer). A mode of arranging the material (hereinafter referred to as double-sided contact type arrangement)
Can be mentioned. FIG. 1 schematically shows an arrangement mode of the porous body by a combination of the electrode pairs (I) and (II) and the arrangements (1) to (3).
[0030]
As shown in FIG. 1, for example, in the I-type electrode pair-non-contact arrangement (1-I), the electrode 22 provided with the dielectric layer 42 on the opposite surface side and the electrode 21 not carrying the dielectric layer. The porous body 11 is disposed between the pair of electrodes 21 and 22 disposed so as to face each other in a state where neither the dielectric layer 42 nor the electrodes 21 and 22 are in contact with each other.
In the II-type electrode pair-non-contact type arrangement (1-II), the dielectric layer is disposed between a pair of electrodes 21 and 22 arranged to face each other by providing dielectric layers 41 and 42 on the opposite surface sides. The porous body 11 is disposed in a state where it does not contact any of the electrodes 41 and 42 and the electrodes 21 and 22.
[0031]
In the I-type electrode pair-single-sided contact arrangement (2-I), the electrode 22 provided with the dielectric layer 42 on the opposite surface side and the electrode 21 not carrying the dielectric layer are arranged facing each other. When the porous body 11 is disposed between the pair of electrodes 21 and 22, (a) the dielectric of the electrode 22 in which one outer surface of the porous body 11 is provided with a dielectric layer on the opposite surface side. In contact with the layer 42 (but not in contact with the electrode 22), and the other outer surface of the porous body is not in contact with the electrode 21 not carrying the dielectric layer, or (B) One outer surface of the porous body 11 is in contact with the electrode 21 that does not carry a dielectric layer, and the other outer surface of the porous body is on the other electrode 22. The dielectric layer 42 is not in contact with the electrode 22 (the electrode 22 is not in contact with the dielectric layer 42).
[0032]
Further, in the type II electrode pair-single-side contact type arrangement (2-II), a porous layer is provided between a pair of electrodes 21 and 22 which are arranged to face each other by providing dielectric layers 41 and 42 on the opposite surface sides. One outer surface of the body 11 is in contact with one of the dielectric layers (dielectric layer 42 in FIG. 1), and the other outer surface of the porous body is in contact with the other dielectric layer (FIG. 1, the porous body 11 is disposed in a state where it is not in contact with the dielectric layer 41) (in contact with the pair of electrodes 21 and 22).
[0033]
Further, in the I-type electrode pair-double-sided contact arrangement (3-I), the electrode 22 provided with the dielectric layer 42 on the opposite surface side and the electrode 21 not carrying the dielectric layer are arranged to face each other. Between the pair of electrodes 21 and 22, one outer surface of the porous body 11 is in contact with the dielectric layer 42 of the electrode 22 provided with a dielectric layer on the opposite surface side, and the porous body 11 The porous body 11 is disposed in a state where the other outer surface is in contact with the electrode 21 not carrying the dielectric layer. The porous body 11 is not brought into contact with the electrode 22 carrying the dielectric layer 42.
In the II-type electrode pair-double-sided contact arrangement (3-II), the dielectric layer 41, 42 is disposed between the pair of electrodes 21, 22 arranged opposite to each other on the opposing surface side. The porous body 11 is disposed in a state in which each of 41 and 42 and the outer surface of the porous body 11 are in direct contact with each other. The porous body 11 should not be in direct contact with the pair of electrodes 21 and 22.
In the method for introducing a sulfur-containing atomic group according to the present invention, it is preferable to dispose an electrode, a dielectric, and an object to be processed using a type II electrode pair in that uniform discharge can be generated.
[0034]
The sulfur-containing atomic group introduction method according to the present invention will be described below with reference to the accompanying drawings.
The basic principle of the method for introducing a sulfur-containing atomic group according to the present invention is shown in FIG. Although FIG. 2 shows a type II electrode pair-double-sided contact arrangement, unless otherwise specified, the following description is for other aspects described so far (eg, type I or type II electrode pair-non-contact arrangement, The same applies to an I-type or II-type electrode pair-single-sided contact type arrangement, or an I-type electrode pair-double-sided contact type arrangement.
[0035]
In the type II electrode pair-double-sided contact type arrangement, as shown in FIG. 2, a pair of electrodes 21 and 22 made of flat electrodes or the like are arranged so as to face each other. The electrode 21 fixes and carries the dielectric layer 41 in surface contact with the opposite surface side, and the electrode 22 also carries and holds the dielectric layer 42 in surface contact with the opposite surface side. Furthermore, although neither of the electrodes 21 and 22 is in contact with each other, a porous layer is provided between the dielectric layer 41 and the dielectric layer 42 so that each of the dielectric layer 41 and the dielectric layer 42 is in direct contact with the outer surface. The mass 11 is arranged. At this time, by pressing the electrode 21 and the electrode 22 with an appropriate pressure, a space is substantially formed between the dielectric layer 41 and the porous body 11 and between the porous body 11 and the dielectric layer 42. Surface contact is made so as not to form. An electrode that does not carry a dielectric layer may be used instead of the electrode that carries a dielectric layer fixedly. In this case, by pressing the electrode 21 and the electrode 22 with an appropriate pressure, the electrode 21 and the dielectric layer 41, the dielectric layer 41 and the porous body 11, the porous body 11 and the dielectric layer 42, and A surface contact is made between the dielectric layer 42 and the electrode 22 so that a space is not substantially formed. The lower limit of the pressure applied between the two electrodes is a pressure that ensures a surface contact between the electrode and the dielectric layer and between the dielectric layer and the porous body and does not substantially form a space. The upper limit is a pressure that does not destroy the shape of the porous body that is the object to be processed.
[0036]
It is preferable that the size of the electrode 21 and the electrode 22 be smaller than the size of the dielectric layer 41 and the dielectric layer 42 with which the electrode 21 and the electrode 22 are in contact with each other, because no spark occurs between the ends of the electrodes 21 and 22. Further, when the size of the electrode 21 or the electrode 22 is the same as the size of the dielectric layer 41 or the dielectric layer 42 with which the electrode 21 or the electrode 22 contacts, a covering material made of a dielectric material around the electrode (for example, vinyl tape) Etc. can prevent a spark between the ends of both electrodes 21 and 22. The electrode 21 is connected to the AC power source 51 and the electrode 22 is grounded. Although FIG. 2 shows a mode in which the AC power source 51 is connected to the electrode 21 and the electrode 22 is grounded, conversely, the AC power source 51 may be connected to the electrode 22 and the electrode 21 may be grounded.
[0037]
When a sine wave AC high voltage is applied from the AC power source 51 in the presence of the sulfur-containing compound gas, a discharge is generated in the internal voids of the porous body 11 to generate plasma. Due to the action of the plasma generated in the internal voids of the porous body 11, the inner surface of the porous body 11 and the sulfur-containing compound react to modify the inner surface of the porous body 11, that is, sulfur-containing atomic groups (for example, , SO_FourOr SO_ThreeH) is introduced. At this time, since the outer surface of the porous body 11 is in contact with the dielectric layer 41 or the dielectric layer 42, the plasma generated in the internal space of the porous body 11 is theoretically the outer surface of the porous body 11. It does not act on the contact point with the dielectric layer. However, in practice, the contact point is a very small area compared to the area of the total surface, so it can be said that substantially all of the outer surface has been treated. In addition, the reaction between the porous body and the sulfur-containing compound is considered to occur not only by the plasma but also by the action of sulfuric anhydride generated by the plasma, so when the porous body and the dielectric layer are separated, The reaction between the anhydrous sulfuric acid generated by the porous material and the porous body also occurs at the contact point. In the II type electrode pair-double-sided contact type arrangement, discharge is generated in the internal voids of the porous body, so that the target object is hardly damaged by spark discharge or the like.
[0038]
In the type II electrode pair-double-sided contact type arrangement shown in FIG. 2, when a voltage is applied between the two electrodes 21 and 22, electric discharge is generated in the internal space of the porous body 11, and plasma is generated. Even in the counter-to-double-side contact type arrangement, when a voltage is applied between both electrodes, a discharge is generated in the internal space of the porous body, and plasma is generated. On the other hand, in the case of an I-type or II-type electrode pair-non-contact type arrangement, or in an I-type or II-type electrode pair-one-side contact type arrangement, when a voltage is applied between both electrodes, a porous body and an electrode or dielectric layer Is generated in the space between and the internal space of the porous body, and plasma is generated.
[0039]
In the description of the embodiment shown in FIG. 2, a case where a sinusoidal AC high voltage is applied between the two electrodes 21 and 22 has been shown. In the sulfur-containing atomic group introduction method of the present invention, The voltage applied between the electrodes is not particularly limited as long as it is a voltage whose voltage value changes with time, preferably a voltage consisting of a continuous waveform or an intermittent waveform that repeatedly increases and decreases in a substantially constant cycle. For example, a sinusoidal AC voltage or a repetitive pulse voltage can be used. The waveform of the applied voltage is not particularly limited, and examples thereof include a sine wave, a triangular wave, and a rectangular wave. Also, the polarity of the applied voltage is not particularly limited, and a unipolar voltage can be used, or a bipolar voltage can be used, but the bipolar voltage is used in terms of high processing efficiency. It is preferable.
[0040]
Examples of the repetitive pulse wave include the bipolar pulse wave shown in FIG. 3, the unipolar pulse wave shown in FIG. 4, or the bipolar rectangular repetitive pulse wave shown in FIG. In these repetitive pulse waves, the rise time of the voltage wave [that is, the time from the reference voltage to reach 90% of the first peak voltage, for example, the time t in FIGS. 3 to 5] is 1 microsecond. Or less, more preferably 0.2 microsecond or less. The preferred range of the frequency when using the repetitive pulse wave (for example, the frequency when the wavelength λ in FIGS. 3 to 5 is one period) is not limited, but the upper limit is preferably 100 KHz, More preferably, it is 50 KHz, The lower limit becomes like this. Preferably it is 10 Hz, More preferably, it is 50 Hz, Most preferably, it is 100 Hz.
[0041]
The repetitive pulse voltage is generated by, for example, a method in which a voltage stored in a capacitor is instantaneously connected to a load by a spark discharge switch, or a method in which a pulsed voltage modulated by a semiconductor switch is boosted through a transformer. Can do.
Further, the rise time of the repetitive pulse wave can be shortened, for example, by reducing the resistance and inductance to the load. In addition, using a magnetic switch or the like, the pulse can be compressed and the rise time can be shortened.
Furthermore, it is preferable that the duration of the current pulse is 1 μsec or less because spark discharge hardly occurs.
[0042]
In the method for introducing a sulfur-containing atomic group according to the present invention, when a repetitive pulse voltage is used as a voltage to be applied to generate a discharge, the lower limit of the repetitive pulse voltage is a distance between electrodes including a dielectric layer or a gas. However, it is preferably 0.5 KVp or more, more preferably 2 KVp or more (KVp indicates a voltage difference from the maximum voltage peak to 0). This is because when the voltage is less than 0.5 KVp, the discharge does not substantially occur, or even if the discharge occurs, the uniform discharge may not occur. The upper limit of the repetitive pulse voltage is not particularly limited as long as it is a voltage that does not cause damage to the porous body and the dielectric, but is preferably 100 KVp or less, more preferably 50 KVp or less. This is because if the voltage exceeds 100 KVp, dielectric breakdown may occur or it may be difficult to increase the frequency of the pulse wave. The electric field strength is preferably 10 to 200 KVp / cm, and more preferably 20 to 100 KVp / cm.
[0043]
In the method for introducing a sulfur-containing atomic group according to the present invention, by using such a repetitive pulse wave, even a porous body (for example, a melt blown nonwoven fabric) that is likely to be pierced by spark discharge is used without making a hole. A surface treatment can be performed. Further, even when the concentration of the sulfur-containing compound is so high that it cannot be carried out by a conventional atmospheric pressure glow discharge (for example, when it is 10% by volume or more), by using such a repetitive pulse wave, Uniform discharge can be generated stably.
Note that these values relating to the voltage applied to generate the discharge greatly depend on the shape of each electrode, the material of the porous body, the discharge voltage waveform, and also the processing time, and are used out of the above range. Sometimes.
[0044]
In type I or type II electrode-non-contact arrangement, type I or type II electrode pair-single-sided contact type arrangement, or type I electrode pair-double-sided contact type arrangement, applied between both electrodes to generate a discharge. As the voltage to be used, it is preferable to use a repetitive pulse voltage having a fast rise, and it is preferable to use a repetitive pulse voltage having a rise time of 1 microsecond or less. In particular, in the case of an I-type or II-type electrode pair-non-contact type arrangement, or an I-type or II-type electrode pair-one-side contact type arrangement, it is preferable to use a pulse voltage so that the discharge becomes uniform.
[0045]
In the type II electrode pair-double-sided contact type arrangement, a normal sine wave AC voltage can be used, or a repetitive pulse voltage can be used. It is preferred to use a fast repetitive pulse voltage.
[0046]
In the method for introducing a sulfur-containing atomic group according to the present invention, when a sine wave AC voltage is used as a voltage to be applied to generate a discharge, the lower limit of the sine wave AC voltage is the distance between electrodes including the dielectric layer. However, it is not particularly limited, but is preferably 0.5 KVp or more, more preferably 2 KVp or more. This is because when the voltage is less than 0.5 KVp, the discharge does not substantially occur, or even if the discharge occurs, the uniform discharge may not occur. Further, the upper limit of the sinusoidal AC voltage is not particularly limited as long as it is a voltage that does not cause damage to the porous body and the dielectric layer, but is preferably 100 KVp or less, more preferably 50 KVp or less. . This is because dielectric breakdown may occur when the voltage exceeds 100 KVp. The electric field strength is preferably 10 to 200 KVp / cm, and more preferably 20 to 100 KVp / cm.
[0047]
In the sulfur-containing atomic group introduction method according to the present invention, the upper limit of the frequency of the sinusoidal AC voltage is not particularly limited, but is preferably 100 KHz, more preferably 50 KHz. This is because if the frequency exceeds 100 KHz, the porous body and the dielectric layer may be overheated and destroyed by dielectric heating. Further, when the frequency is 50 KHz or less, the porous body, the dielectric, and the electrode are hardly heated, which is more preferable in that the treatment can be stably performed for a long time.
The lower limit of the frequency is preferably 10 Hz, more preferably 50 Hz. This is because, when the frequency is less than 10 Hz, the processing efficiency due to discharge may be reduced. A frequency of 50 Hz or higher is more preferable because the processing efficiency is high and the processing time is shortened.
[0048]
In the method for introducing a sulfur-containing atomic group according to the present invention, the output of a sinusoidal alternating current applied to generate a discharge depends on the shape of each electrode, the dielectric layer used, the material or thickness of the object to be processed, and the like. Therefore, although not particularly limited, in the case of the II type electrode pair-double-sided contact type arrangement, when the pair of electrodes is processed by sandwiching the porous body in a certain region (for example, see FIG. 2), 0 .01-5W / cm²It is preferable that
In addition, in the case of the type II electrode pair-double-sided contact type arrangement, when the porous body is linearly sandwiched by a pair of roll electrodes, the output of the sinusoidal alternating current is 0.1 to 9 W / cm. It is preferable that it is 0.1-6 W / cm. In addition, when processing a porous body in a linear form and using a plurality of roll electrodes, the range of the sine wave AC output means a value per electrode. .
[0049]
In the type II electrode pair-double-sided contact type arrangement, when the output of the sinusoidal alternating current is lower than the above range (that is, 0.01 W / cm when processing a porous body sandwiched in a certain region)²Or less than 0.1 W / cm when processing the porous body in a linear form), since the discharge mainly occurs at the location where the porous body is easily discharged, The surface may not be treated uniformly. Further, when the output of the sinusoidal alternating current is higher than the above range (that is, 5 W / cm when processing the porous body sandwiched in a certain region)²Or when the porous body is sandwiched in a linear shape and exceeds 9 W / cm), the porous body may have holes due to arc discharge.
[0050]
In the method for introducing a sulfur-containing atomic group according to the present invention, the peak current density (J; unit = mA / cm).²) And the voltage rise time (T: unit = nanosecond) satisfy the following relational expression (1) or relational expression (2), the processing efficiency is high, and discharge is performed uniformly without causing spark discharge. be able to.
When the voltage rise time (T) is 150 ns or less:
(150 / T) × 150 ≦ J ≦ (1100 / T)²× 200 (1)
When the voltage rise time (T) exceeds 150 ns:
150 ≦ J ≦ (1100 / T)²× 200 (2)
The peak current density is a value obtained by dividing the peak value of the discharge current by the dielectric area.
[0051]
The electrode material that can be used in the method for introducing a sulfur-containing atomic group according to the present invention has a specific resistance of preferably 10^ThreeΩ · cm or less, more preferably 10⁰A conductor of Ω · cm or less can be used, for example, metal (for example, stainless steel, aluminum, or tungsten), conductive metal oxide, carbon, or conductor (for example, metal powder or carbon powder). Conductive rubber or the like in which rubber and rubber are combined can be used.
Moreover, as a shape of an electrode, a sheet-like electrode, a plate-like electrode, or a columnar electrode can be used, for example. When the porous body and the electrode move relatively as in the case of passing the porous body between the pair of roll electrodes, the porous body is made so that the surface of the porous body is hardly damaged. A cylindrical electrode that can rotate itself with the central axis of the cylinder as a rotation axis in synchronization with the parallel movement of the cylinder is preferable.
[0052]
The dielectric layer that can be used in the method for introducing a sulfur-containing atomic group according to the present invention may be non-porous as a whole or may include a porous portion as a part thereof. If only the dielectric layer composed entirely of a porous portion is used as the dielectric layer, a spark discharge may occur inside the object to be processed and the porous portion of the dielectric. Therefore, it is not preferable to use such a dielectric layer in the present invention. For the same reason, it is not preferable to use a dielectric layer including a porous portion continuous in the thickness direction as the dielectric layer.
When a dielectric layer having a porous portion is used on the contact surface with the object to be processed, the contact surface between the dielectric layer and the object to be processed is smaller than when a dielectric layer made entirely of non-porous material is used. Since it reduces, the outer surface of a to-be-processed object can be processed more efficiently.
[0053]
Examples of the material of the dielectric layer that can be used in the method for introducing a sulfur-containing atomic group according to the present invention include glass, ceramic (for example, alumina, titanium oxide, zirconia, strontium titanate, barium titanate, etc.), rubber ( For example, a synthetic rubber such as silicone rubber, chloroprene rubber, butadiene rubber, or natural rubber), or a thermoplastic resin (such as polytetrafluoroethylene, polyethylene, polypropylene, or polyester) can be used. Rubber or a thermoplastic resin is preferably used for the dielectric layer in contact with the porous body that is the object to be processed, particularly the contact surface, in terms of excellent elasticity. It is more preferable to use rubber from the viewpoint of excellent adhesiveness. In particular, it is preferable to use rubber that does not easily damage the surface of the object to be processed or polytetrafluoroethylene that is resistant to dielectric breakdown. From the viewpoint of durability, it is particularly preferable to use glass, ceramic or polytetrafluoroethylene.
Although the thickness of a dielectric material layer is not specifically limited, It is preferable that it is 0.01-20 mm, and it is more preferable that it is 0.1-10 mm. If it is thicker than 20 mm, a very high voltage is required for discharging, and if it is less than 0.01 mm, the mechanical strength decreases and dielectric breakdown tends to occur.
[0054]
In the method for introducing a sulfur-containing atomic group according to the present invention, the distance between the dielectric layer in the electrode provided with the dielectric layer on the opposite surface side and the object to be processed, or the electrode not carrying the dielectric layer, Although the distance with a process body is not specifically limited, It is preferable that it is 0 (namely, the state which is contacting)-100 mm. This is because if it exceeds 100 mm, a high voltage is required to generate electric discharge, and a hole may be formed in the porous body.
[0055]
In the method for introducing a sulfur-containing atomic group according to the present invention, as means for supplying the surface treatment gas to the internal voids of the porous body and / or the space between the porous body and the electrode or dielectric layer, for example, A method of forcibly sending a surface treatment gas into the porous body, a method of spraying a surface treatment gas in and around the porous body, a method of making the atmosphere of the surface treatment gas around the porous body, or Before placing between the pair of electrodes, a method of placing the porous body after filling the internal voids with the surface treatment gas in advance can be used. These methods can be used alone or in combination, and can be opened or closed. Can be implemented in the system. As the above-mentioned means, the inner space of the porous body is filled with the surface treatment gas in advance before being disposed between the electrodes (for example, after the surface treatment gas is passed through the inner space of the porous body). Is preferred. In the case of an I-type or II-type electrode pair-non-contact type arrangement, or an I-type or II-type electrode pair-single-sided contact type arrangement, the surface treatment gas is excellent in diffusibility, so that the discharge treatment can be performed uniformly. it can.
[0056]
For example, when a discharge is generated by applying a high voltage while supplying a surface treatment gas to the internal voids and / or surroundings of the porous body using a gas supply pipe or the like, the internal voids of the porous body, And / or by the action of the plasma generated in the space between the porous body and the electrode or dielectric layer, the sulfur-containing compound gas contained in the surface treatment gas reacts with the total surface of the porous body, resulting in porosity. It is possible to introduce a modification of the total surface of the mass, ie sulfur-containing atomic groups.
[0057]
In the method for introducing a sulfur-containing atomic group according to the present invention, it is preferable to perform a discharge treatment after attaching a surfactant to the porous body. Pretreatment with a surfactant tends to increase the amount of sulfur-containing atomic groups introduced. Examples of the surfactant include hydrocarbon-based, silicone-based, or fluorine-based surfactants.
[0058]
In the pretreatment with the surfactant, for example, the surfactant is dissolved or suspended in an appropriate solvent or medium, and the solution or suspension is impregnated into the porous body, or the solution or suspension is removed. After spraying or coating on the surface to be treated of the porous body, the surfactant can be supported on the surface to be treated of the porous body by removing only the solvent or medium.
[0059]
The method for introducing a sulfur-containing atomic group according to the present invention is not limited to the embodiment shown in FIG. 2 in which the discharge is generated while the porous body is stationary, and the porous body is continuously moved while moving the porous body. Total surface treatment can also be performed. In this case, the electrode is not limited to the following arrangement mode, but is a type II electrode pair-non-contact type arrangement (1-II) or a type II electrode pair-single-sided contact type arrangement (2-II). It is preferable to dispose a dielectric layer and an object to be processed. An embodiment of the method of the present invention that is continuously processed is shown in FIG. In the embodiment of the method of the present invention shown in FIG. 6, a type II electrode pair-double-sided contact type arrangement is adopted as an embodiment for arranging the porous body between the electrodes. Other aspects described so far (for example, type I or type II electrode pair—non-contact type arrangement, type I or type II electrode pair—single side contact type arrangement, or type I electrode pair—double side contact type arrangement) apply.
[0060]
In this embodiment, the columnar electrode 21 and the columnar electrode 22 are disposed so as to face each other. The surfaces of the electrodes 21 and 22 are covered with a dielectric layer 41 and a dielectric layer 42, respectively. The electrode 21 and the electrode 22 may be capable of rotating themselves with the cylindrical central axis as a rotation axis, or may be fixed without rotating. When the porous body moves, it is preferable that the electrode is capable of rotating itself with the central axis of the cylinder as a rotation axis in that it is difficult to damage the surface of the porous body.
[0061]
The electrode 21 is connected to the AC power source 51 and the electrode 22 is grounded. The porous body 11 includes a dielectric layer 41 and a dielectric layer 41 supported on the surfaces of the electrodes 21 and 22, respectively, by transfer means (for example, a pair of delivery rollers: not shown) provided upstream of the electrodes 21 and 22. The dielectric layer 42 is continuously supplied at a predetermined speed in the direction indicated by the arrow A, and passes between both dielectric layers 41 and 42 while being in contact therewith. The porous body 11 that has passed between the dielectric layers 41 and 42 is continuously transferred at a predetermined speed by a transfer means (for example, a pair of delivery rollers: not shown) provided downstream of the electrodes 21 and 22. Be transported. A driving means (for example, a motor) for supplying a driving force for transferring the porous body 11 can be connected to the feed roller and / or the rotatable electrode.
[0062]
The supply speed and the transfer speed of the porous body 11 are not particularly limited, and may be a constant speed or a speed that changes periodically or irregularly. These speeds are preferably constant speeds such that the surface treatment time of the porous body is 0.1 seconds or more. This is because if the speed is higher than this, a sufficient total surface treatment effect may not be obtained.
[0063]
When the porous body 11 passes between the dielectric layers 41 and 42 while being in contact therewith, the nozzle 63 provided on the side wall of the surface treatment gas supply pipes 61 and 64 from both sides of the porous body 11. , 65, when an AC high voltage is applied from the AC power source 51 while supplying the surface treatment gas to the treatment region, the gas is sandwiched between the contact surfaces of the dielectric layer 41 and the dielectric layer 42 and the porous body 11. Discharge occurs in the internal voids of the porous body 11, and plasma is generated. The surface treatment gas supply pipe 61 communicates with a gas cylinder (not shown) through a connecting pipe 62. Similarly, the surface treatment gas supply pipe 64 communicates with a gas cylinder (not shown). Due to the action of the plasma generated in the internal space of the porous body 11, the inner surface of the porous body 11 is modified, that is, the introduction of sulfur-containing atomic groups is performed. At this time, the plasma generated in the internal voids of the porous body 11 does not act on the contact surfaces between the dielectric layer 41 and the dielectric layer 42 and the porous body 11. However, since the porous body 11 is continuously transferred at a predetermined speed, the outer surface of the porous body 11 that is the contact surface is separated from the dielectric layer 41 and the dielectric layer 42 one after another, and separated. Immediately after this, sulfuric anhydride generated by the plasma reacts with the outer surface of the porous body, and the outer surface of the porous body 11 is modified.
[0064]
Since the porous body 11 is continuously transferred at a predetermined speed, the untreated porous body 11 is continuously supplied between the dielectric layers 41 and 42, while the total surface is modified. The broken porous body 11 is continuously supplied from between both the dielectric layers 41 and 42, and the total surface treatment of the porous body 11 can be performed continuously. In the embodiment shown in FIG. 2, by providing a transfer means (for example, the pair of delivery rollers), the porous body can be continuously transferred to perform continuous processing.
[0065]
In the embodiment shown in FIG. 6, only one cylindrical electrode 21 supporting the dielectric layer 41 is provided on the surface, but the number of electrodes 21 is not particularly limited, and one or a plurality of electrodes 21 are provided. Can be provided. Providing a plurality of electrodes carrying a dielectric layer so that an arbitrary point on the outer surface of the porous body can contact the dielectric layer carried on the surface of the electrode a plurality of times is effective. Is preferable in that it can increase the processing speed.
[0066]
As the porous body whose total surface can be treated by the method for introducing a sulfur-containing atomic group according to the present invention, a porous body made of any organic material can be used.
As the porous body, a porous body made of an organic material having an arbitrary whole and surface S / C ratio and a surface O / C ratio can be used, and the surface S / C ratio is 7 × 10.^-FourIt is preferable to use a porous body made of a material having a surface O / C ratio of less than 0.2 and a surface S / C ratio of 7 × 10.^-FourThe surface O / C ratio is less than 0.2, and the overall S / C ratio is 1 × 10^-3It is more preferable to use a porous body made of a material less than the above, and it is even more preferable to use a porous body made of an organic material (particularly an organic synthetic polymer compound) substantially free of sulfur atoms and oxygen atoms.
[0067]
Examples of the organic material include various organic polymer compounds, particularly various organic synthetic polymer compounds, for example, polyolefins such as polyethylene and polypropylene, polyesters, polycarbonates, polyvinyl chloride, fluorinated ethylene propylene copolymers (FEP), and polypropylene. And vinylidene fluoride (PVDF) or vinylidene fluoride-trifluoroethylene copolymer.
[0068]
Examples of organic materials not containing sulfur atoms and oxygen atoms (especially organic synthetic polymer compounds) include polyolefins such as polypropylene, polyethylene, and polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polytetrafluoroethylene ( PTFE), polystyrene, or polyimide.
[0069]
Examples of the porous body made of various materials include a fiber type porous body, a film type porous body, and a foam type porous body. A fibrous porous body consists of a woven fabric, a knitted fabric, or a nonwoven fabric, for example. Examples of the nonwoven fabric include a dry nonwoven fabric (for example, a hydroentangled nonwoven fabric, a needle punched nonwoven fabric, a binder-bonded nonwoven fabric, a heat-sealed nonwoven fabric, a spunbonded nonwoven fabric, or a melt blown nonwoven fabric), a wet nonwoven fabric, or a combination thereof. Can do. Examples of the foam include an open-cell foam made of a polyolefin-based, polyester-based, or polyurethane-based resin. Examples of the film-type porous body include a film having a concavo-convex structure and a holed film.
[0070]
The method for introducing a sulfur-containing atomic group according to the present invention can be applied particularly to the treatment of a fibrous porous body made of a non-conductive organic material (particularly an organic synthetic polymer compound), for example, a non-woven sheet, preferably The present invention can be applied to the treatment of nonwoven fabric sheets that can be used as battery separators (particularly alkaline battery separators). Non-woven fabrics that can be used as battery separators are not limited to these, but include, for example, polyolefin fibers, that is, polyethylene, ethylene copolymers, polypropylene, propylene copolymers, polybutenes, butenes. Non-woven fabric made of fibers containing at least one of a copolymer, polymethylpentene, or a pentene copolymer as a resin component, for example, water entanglement, thermal fusion, melt blow, or a combination thereof Can be used. It is preferable from the point of alkali resistance that the nonwoven fabric used as a battery separator consists essentially of polyolefin fibers.
[0071]
The battery separator of the present invention has a high surface S / C ratio and a surface O / C ratio at the same time, and is excellent in initial and long-term liquid retention and wettability. Therefore, the separator for primary batteries and secondary batteries In particular, it can be used as a separator for alkaline primary batteries and alkaline secondary batteries. Examples of the alkaline primary battery include an alkaline manganese battery, a mercury battery, a silver oxide battery, and an air battery. Examples of the alkaline secondary battery include a nickel-cadmium battery, a silver-zinc battery, A silver-cadmium battery, a nickel-zinc battery, a nickel-hydrogen battery, or the like can be given.
[0072]
【Example】
EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but these do not limit the scope of the present invention.
[Example 1]
As the object to be treated, a nonwoven fabric obtained by hydroentangling a fiber web formed of polyethylene / polypropylene 17-divided fibers and then fusing polyethylene ultrafine fibers by fusion treatment was used.
The sulfur-containing atomic group introduction treatment was carried out by a type II electrode pair-single-sided contact arrangement (2-II). A flat stainless steel electrode (size = 150 mm × 210 mm) was used as the electrode, and a polytetrafluoroethylene (PTFE) film (thickness = 0.1 mm) was used as the dielectric layer. The non-woven fabric is arranged between the two electrodes carrying the PTFE membrane on the opposite surface side so as to come into contact with one PTFE membrane and the distance from the other PTFE membrane is 0.5 mm, as shown in FIG. A pulse voltage having a waveform (voltage = 6.8 KVp, peak current = 400 A, frequency = 75 Hz, rise time = 0.1 microsecond) was applied to the electrode to generate a discharge. In the treatment, after removing air (0.1 Torr) in advance, sulfur dioxide (SO₂) A mixed gas of gas and air (mixing volume ratio = 1: 1) was sealed, and this was performed for 10 minutes in a sealed chamber (under atmospheric pressure).
[0073]
The surface S / C ratio and the surface O / C ratio on the surface of the treated nonwoven fabric were determined by an X-ray photoelectron spectrometer [JEOL Ltd. JPS-9000MX; excitation source = Mg-Kα, output = 10 KV-10 mA] The total S / C ratio in the whole treated nonwoven fabric was determined by ion chromatography. Table 1 shows the results of the obtained surface and overall S / C ratio and the surface O / C ratio. Moreover, the kind of atomic group introduced into the treated nonwoven fabric was determined by the X-ray photoelectron spectrometer. The types of atomic groups introduced into the treated nonwoven fabric are mainly SO_Four, COOH, SO_ThreeH, OH, and CO.
When one drop of water was dropped on the treated nonwoven fabric, it was absorbed into the nonwoven fabric within 0.5 seconds. In addition, in the nonwoven fabric obtained by the comparative example 1 mentioned later, 3 seconds or more were required until the dripped water droplet was absorbed.
[0074]
[Comparative Example 1]
As a to-be-processed object, the same thing as the nonwoven fabric used in Example 1 was used. The nonwoven fabric was treated with fuming sulfuric acid having a concentration of 15% at a temperature of 60 ° C. for 2 minutes. The treated nonwoven fabric was analyzed by the method described in Example 1. Table 1 shows the results of the obtained surface and overall S / C ratio and the surface O / C ratio. The types of atomic groups introduced into the treated nonwoven fabric are mainly SO_ThreeH and SO_FourMet.
[0075]

[0076]
Examples 2 to 10
Various experiments were performed by changing the type of gas present during the discharge treatment.
(1) Object to be processed and processing conditions
As an object to be treated, a non-woven fabric (thickness = 0.0) obtained by hydroentangling a fiber web made of polyethylene / polypropylene 17-divided fibers, and further fusing polyethylene ultrafine fibers by fusion treatment. 25 mm) was used.
The sulfur-containing atomic group introduction treatment was carried out by a type II electrode pair-single-sided contact arrangement (2-II). A flat stainless steel electrode (size = 150 mm × 210 mm) was used as the electrode, and a polytetrafluoroethylene (PTFE) film (thickness = 0.26 mm) was used as the dielectric layer. The non-woven fabric was placed between the two electrodes carrying the PTFE membrane on the opposite surface side so as to come into contact with one PTFE membrane and the distance from the other PTFE membrane was 0.5 mm.
The applied pulse voltage is a pulse voltage having the waveform shown in FIG. 5 (voltage = 10 KVp, peak current density = 440 mA / cm², Frequency = 125 Hz, rise time = 200 nsec).
[0077]
(2) Processing procedure
The specific processing procedure is as follows.
After setting an electrode and a nonwoven fabric in a vacuum desiccator, the pressure was reduced with a rotary pump. After the inside of the desiccator was replaced with the mixed gas shown in FIG. 7 three times by the gas mixer, the mixed gas shown in FIG. 7 was introduced to 1 atm. The above-mentioned pulse voltage was applied for 5 minutes to carry out a discharge treatment. Subsequently, the mixed gas was degassed and air was introduced. The nonwoven fabric was taken out, washed with water and then air dried.
[0078]
[Comparative Example 2]
The gas to be present during the discharge treatment is 6.5% by volume-SO.₂The same operation as in Examples 2 to 10 was repeated except that /93.5% by volume-He gas was used.
[0079]
[Comparative Example 3]
After performing the discharge treatment in 100% He gas, the inside of the desiccator is replaced with oxygen gas, and the non-woven fabric is left for 15 minutes in the desiccator, and then 6.5 vol% -SO in the desiccator.₂/93.5% by volume-He was introduced to 1 atm, and the same operations as in Examples 2 to 10 were repeated except that the solution was allowed to stand for 5 minutes.
[0080]
[Comparative Example 4]
As a to-be-processed object, the same thing as the nonwoven fabric used in Examples 2-10 was used. The nonwoven fabric was sulfonated by immersing in a fuming sulfuric acid bath (temperature 60 ° C.) having a concentration of 15% for 2 minutes, and then at an output of 1500 W for 60 seconds (load energy per unit area = 10.24 J / cm).²) Corona discharge treatment.
[0081]
【Evaluation of the physical properties】
(1) Overall S / C ratio of treated nonwoven fabric
The total S / C ratio of the treated nonwoven fabric was measured by the following procedure.
NaHCO_Three(84 mg) is dissolved in pure water (100 ml) and 30% H₂O₂An aqueous solution (1 ml) was added to prepare an absorbing solution. This absorption liquid (5 ml) was put in a combustion flask (manufactured by Rika Hamada, FHO-A type, 500 ml), and the inner wall of the combustion flask was well wetted with the absorption liquid.
A sample (about 20 mg) was precisely weighed from the treated nonwoven fabric, wrapped in ashless filter paper, set in a platinum basket in the combustion flask, and then the combustion flask was filled with oxygen. A current was passed through the platinum soot to burn the sample. After the sample was burned, the combustion flask was shaken well and left for 10 minutes. 10 ml of pure water was put into the injection part of the combustion flask, the inner wall was washed with this pure water, and left for several minutes. The absorption liquid in the combustion flask was diluted to 50 ml with pure water using a measuring flask, and used as a test liquid.
Using ion chromatography (DIONEX, 2000i / SP), test solution SO_Four ^2-The concentration of was measured. In addition, SO_Four ^2-Calibration was performed using a standard solution.
The total S / C was calculated from the following formula.

In the above formula, W is the sample mass (g), and a is the SO_Four ^2-Concentration (mg / ml), b is SO_Four ^2-Molecular weight (ie 96) and c is C_ThreeH₆The molecular weight of (ie 42). In Examples 2 to 10 and Comparative Examples 2 to 4, the samples are made of polyolefin._ThreeH₆The number of carbon atoms was calculated assuming that The results are shown in FIG.
[0082]
(2) Measurement of surface S / C ratio and surface O / C ratio
Measurement was performed under the following conditions using an X-ray photoelectron spectrometer (JPS-9010MX, manufactured by JEOL Ltd.).
A sample was cut out from the treated nonwoven fabric, washed with pure water, dried, and fixed to a sample holder. Using Mg—Kα as an excitation source, an applied voltage value of 10 KV, a beam current value of 10 mA, and a photoelectron escape angle of 90 °, carbon atoms (C_is) Peak area, sulfur atoms (2P_3/2) Peak area and oxygen atoms (O_is) Were measured, the photoionization cross-sectional area was corrected, and the S / C ratio and the O / C ratio were calculated. The results are shown in FIG.
[0083]
(3) Battery capacity maintenance rate
As a current collector of the electrode, a paste type nickel positive electrode (width = 33 mm, length = 182 mm) using a foamed nickel base material and a paste type hydrogen storage alloy negative electrode (mesh metal alloy, width = 33 mm, length = 247 mm) ) And created. Next, a sample piece (width = 33 mm, length = 410 mm) was cut from the sulfonated nonwoven fabric prepared in Example 2, Example 3, Example 5, Example 7 and Example 10, and Comparative Examples 2 and 3. Then, each electrode was sandwiched between the positive electrode and the negative electrode and wound in a spiral shape, thereby creating an SC-type electrode group. After this electrode group is housed in an outer can, 5N potassium hydroxide and 1N-lithium hydroxide are injected into the outer can as an electrolytic solution, sealed, and a cylindrical nickel-hydrogen battery (capacity 2000 to 2100 mAh) is obtained. Created. Next, each cylindrical nickel-hydrogen battery was charged in a constant temperature bath at 20 ° C. for 12 hours (120% charge) at a charging rate of 0.1 C, and discharged at a discharging rate of 0.1 C until the final voltage reached 1 volt. The battery was activated by carrying out 5 cycles of charging / discharging in which one cycle was performed.
Then, charging was performed for 12 hours (120% charging) at a charging rate of 0.1 C in a constant temperature bath at 20 ° C., and discharging was performed at a discharging rate of 0.1 C until the final voltage reached 1 volt, and the initial capacity (A) was measured. .
Next, after charging for 12 hours (120% charging) at a charging rate of 0.1 C in a constant temperature bath at 20 ° C., it was left in a constant temperature room at a temperature of 65 ° C. for 5 days. Thereafter, the battery was discharged at a discharge rate of 0.1 C in a constant temperature bath at 20 ° C. until the final voltage reached 1 volt, and the remaining capacity (B) was measured. From these results, the capacity retention rate was calculated by the following formula.
Capacity maintenance rate (%) = (B / A) × 100
The results are shown in FIG. As shown in FIG. 7, it was found that when the overall S / C ratio was 2 or more, the capacity retention ratio was superior.
[0084]
【The invention's effect】
The sulfur-containing atomic group-introduced porous material according to the present invention has a high surface S / C ratio and a high surface O / C ratio at the same time. Not only is it improved, but it is also excellent in terms of its hydrophilic durability, and further, ion absorbability, ammonia adsorption, biocompatibility, etc. are newly imparted or improved.
According to the method for introducing a sulfur-containing atomic group according to the present invention, a sulfur-containing atomic group can be introduced into the total surface of the porous body with high efficiency by discharge under atmospheric pressure without using a large-scale apparatus, Treatment of waste liquid containing high concentration sulfuric acid is unnecessary. Further, since sulfur-containing atomic groups are mainly introduced on the surface of the material constituting the porous body, the strength of the porous body is hardly deteriorated. According to the method of the present invention, a novel sulfur-containing atomic group-introduced porous body exhibiting a high surface S / C ratio and a high surface O / C ratio can be produced.
[0085]
The battery separator of the present invention has the following various excellent effects because the surface S / C ratio and the surface O / C ratio simultaneously show high numerical values. That is, the battery separator of the present invention has excellent wettability. In addition, the battery separator of the present invention is newly imparted with a high degree of initial and long-term hydrophilicity, and is not only highly improved in hydrophilicity but also excellent in terms of durability of the hydrophilicity. Moreover, since it is excellent in oxidation resistance, it has a long life as a separator. Furthermore, since the battery separator of the present invention has an excellent capacity retention, the self-discharge suppressing action is high.
[Brief description of the drawings]
FIG. 1 is an explanatory view schematically showing various aspects of the method of the present invention.
FIG. 2 is a sectional view schematically showing the basic principle of the method of the present invention.
FIG. 3 is an explanatory diagram showing the shape of a repetitive pulse wave that can be used in the method of the present invention.
FIG. 4 is an explanatory diagram showing the shape of another repetitive pulse wave that can be used in the method of the present invention.
FIG. 5 is an explanatory diagram showing still another repetitive pulse wave shape that can be used in the method of the present invention.
FIG. 6 is a perspective view schematically showing one embodiment of the method of the present invention.
FIG. 7 is a table showing the results of Examples 2 to 10 and Comparative Examples 2 to 4.
[Explanation of symbols]
11 ... porous body; 21, 22 ... electrode;
41, 42 ... non-porous dielectric layer; 51 ... AC power supply;
61, 64 ... gas supply pipes; 62 ... connecting pipes;
63, 65 ... nozzles.

Claims (9)

A sulfur-containing atomic group-introduced porous body in which a sulfur-containing atomic group is introduced into at least a part of the total surface of the porous body made of an organic material ,
The ratio (S / C) of the number of sulfur atoms (S) to the number of carbon atoms (C) measured by an X-ray photoelectron spectrometer on the surface into which the sulfur-containing atomic group is introduced is 7 × 10 ⁻⁴ or more. ,
The ratio (O / C) of the number of oxygen atoms (O) to the number of carbon atoms (C) measured by an X-ray photoelectron spectrometer on the surface introduced with the sulfur-containing atomic group is 0.2 or more,
The sulfur-containing atomic group-introduced porous body has a sulfur-containing ratio (S / C) of 1 × 10 ⁻³ or more, which is the ratio of the number of sulfur atoms (S) to the number of carbon atoms (C). Atomic group introduction porous body.   X-ray photoelectrons on the surface into which the sulfur-containing atomic group has been introduced, relative to the ratio (S / C = B) of the number of sulfur atoms (S) to the number of carbon atoms (C) in the entire sulfur-containing atomic group-introduced porous body The sulfur-containing ratio according to claim 1, wherein the ratio (A / B) of the number of sulfur atoms (S) to the number of carbon atoms (C) measured by a spectrometer (S / C = A) is 15 or more. Atomic group introduction porous body.   The sulfur-containing atomic group-introduced porous material according to claim 1 or 2, wherein the porous material before the sulfur-containing atomic group-introducing treatment is made of an organic material that substantially does not contain sulfur atoms and oxygen atoms.   The sulfur-containing atomic group-introduced porous body according to any one of claims 1 to 3, wherein the porous body is a nonwoven fabric.   A battery separator comprising the sulfur-containing atomic group-introduced porous body according to claim 4. A porous body made of an organic material is disposed between a pair of electrodes disposed opposite to each other by providing a dielectric layer on the opposite surface side of at least one of the electrodes, and the volume of the surface treatment gas is 10 volumes. % Of a sulfur-containing compound gas and at atmospheric pressure, a voltage is applied between the electrodes to generate a discharge, and at least one of the total surface of the porous body is generated. To introduce sulfur-containing atomic groups into the plant. A porous body made of an organic material is disposed between a pair of electrodes disposed opposite to each other by providing a dielectric layer on the opposite surface side of at least one of the electrodes, and the volume of the surface treatment gas is 10 volumes. % Porous material characterized in that a discharge is generated by applying a voltage between the electrodes in the presence of a sulfur-containing compound gas and oxygen gas and at atmospheric pressure. A method for introducing a sulfur-containing atomic group into at least a part of the total surface of the substrate. Between the pair of electrodes arranged facing each other with a dielectric layer provided on each facing surface side, the pair of electrodes are not in direct contact with each other, but each of the dielectric layers is in direct contact with the outer surface. The porous body made of an organic material is disposed so that the two electrodes are present in the presence of 10% by volume or more of a sulfur-containing compound gas with respect to the total volume of the surface treatment gas and under atmospheric pressure. Introducing a sulfur-containing atomic group into at least a part of the total surface of the porous body, wherein a voltage is applied between the electrodes to generate an electric discharge in the internal space of the porous body sandwiched between the electrodes Method.   The method according to any one of claims 6 to 8, wherein a discharge is generated by applying a repetitive pulse voltage having a rise time of 1 microsecond or less between the electrodes.

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