JP4283453B2 - Microorganism propagation carrier - Google Patents

Description

（式（１）中、Ｒ₁及びＲ₂はアルキル基であり、ＭはＮａ、Ｋ、Ｍｇ、Ｚｎ又はＮＨ₃である）
【０００８】
【化１０】

（式（２）中、Ｒ₃及びＲ₄は水素又はアルキル基であり、ＭはＮａ、Ｋ、Ｍｇ、Ｚｎ又はＮＨ₃である）
【０００９】
【化１１】

（式（３）中、Ｒ₅は水素又はアルキル基であり、ＭはＮａ、Ｋ、Ｍｇ、Ｚｎ又はＮＨ₃である）
【００１０】
【化１２】

（式（４）中、Ｒ₆及びＲ₇は水素又はアルキル基であり、ＭはＮａ、Ｋ、Ｍｇ、Ｚｎ又はＮＨ₃であり、n1は自然数である）
【００１１】
本発明の請求項２に記載の発明（以下、「本発明２」と記す）の微生物繁殖用担持体は、ポリオレフィン系樹脂からなる多孔体に、上記式（１）〜（４）の何れかで示される界面活性剤が０．４〜２０ｇ／ｍ³になるように塗布又は含浸されてなる。
【００１２】
まず、本発明１について説明する。本発明１で使用される多孔体は、 ポリオレフィン系樹脂及び上記式（１）〜（４）の何れかで示される界面活性剤からなり、その形態は特には限定されず、例えば、連続気泡性発泡体、繊維体、粒状ゲル等が挙げられる。中でも、解繊したりすることがなく、かつ、体積あたりの表面積が多く、微生物の繁殖効率に優れているので、連続気泡性発泡体が好ましい。
【００１３】
上記多孔体を構成する樹脂としては、ポリオレフィン系樹脂が用いられ、多孔体が連続気泡性発泡体である場合は、架橋されているのが好ましい。
【００１４】
上記ポリオレフィン系樹脂としては、例えば、低密度ポリエチレン、中密度ポリエチレン、高密度ポリエチレン、直鎖状低密度ポリエチレンなどのエチレンを主成分とするエチレン−α−オレフィン共重合体、エチレンを主成分とするエチレン−酢酸ビニル共重合体、エチレンを主成分とするエチレン−エチルアクリレート共重合体、ポリプロピレン、プロピレンを主成分とするプロピレン−α−オレフィン共重合体、プロピレンを主成分とするエチレン−プロピレン−ブテン三元共重合体、ポリブテン等が挙げられ、これらは単独で使用しても２種以上併用してもよい。上記エチレン−α−オレフィン共重合体を構成するα−オレフィンとしては、例えば、プロピレン、１−ブテン、１−ペンテン、４−メチル−１−ペンテン、１−ヘキセン、１−ヘプテン、１−オクテン等が挙げられ、上記プロピレン−α−オレフィン共重合体を構成するα−オレフィンとしては、例えば、エチレン、１−ブテン、１−ペンテン、４−メチル−１−ペンテン、１−ヘキセン、１−ヘプテン、１−オクテン等が挙げられる。
【００１５】
また、上記ポリオレフィン系樹脂の比重は水よりも小さい場合が多く、該樹脂から得られる多孔体を微生物繁殖用担持体として使用した際、その内部に水が完全に浸透しても曝気条件によっても水没し難いことがあり、初期の水中浮沈流動性が低下するので、無機充填剤を添加してもよい。
【００１６】
上記無機充填剤としては、例えば、炭酸カルシウム、タルク、硫酸バリウム、水酸化アルミニウム、ゼオライト等が挙げられ、これらは単独で使用しても２種以上併用してもよい。無機充填剤の添加量は、少なくなると添加の効果が得られず、多くなると発泡段階で発泡し難くなるので、上記ポリオレフィン系樹脂１００重量部に対し、１０〜８０重量部が好ましく、より好ましくは２０〜６０重量部であり、無機充填剤添加後の樹脂の比重が水と同等又は水よりも若干大きくなるように調整するのが好ましい。
【００１７】
上記式（１）で示される界面活性剤としては、具体的には、例えば、ジ−２−エチルヘキシルスルホコハク酸エステルナトリウム塩、ステアリル−２−エチルヘキシルスルホコハク酸エステルナトリウム塩などのｎ−パラフィン−２−エチルヘキシルスルホコハク酸エステルナトリウム塩等が好ましい。上記式（２）で示される界面活性剤としては、具体的には、例えば、ジ−イソプロピルナフタレンスルホン酸ナトリウム塩が好ましい。
【００１８】
上記式（３）で示される界面活性剤としては、具体的には、例えば、イソプロピルベンゼンスルホン酸ナトリウム塩が好ましい。上記式（４）で示される界面活性剤としては、具体的には、例えば、２−エチルヘキシルエトキシサルフェートナトリウム塩が好ましい。
【００１９】
上記式（１）〜（４）の何れかで示される界面活性剤の中でも、上記式（１）で示される界面活性剤が、少量の添加で優れた水没性を有する微生物繁殖用担持体が得られるので、特に好ましい。上記式（１）〜（４）の何れかで示される界面活性剤は、単独で使用しても２種以上併用してもよく、その添加量は、少なくなると得られる微生物繁殖用担持体の水没性が低下し、多くなると得られる微生物繁殖用担持体の使用時に泡出ちが多くなり、使用に適さなくなり、また、多孔体が連続気泡性発泡体の場合は、連続気泡性発泡体の発泡段階での発泡性が低下するので、上記ポリオレフィン系樹脂１００重量部に対し、０．１〜５重量部に限定され、好ましくは０．２〜２重量部である。また、上記式（１）〜（４）の何れかで示される界面活性剤以外の界面活性剤を使用すると、微生物繁殖用担持体の使用中に泡立ちが多くなり、使用に適さない。
【００２０】
上記ポリオレフィン系樹脂及び界面活性剤から多孔体を得る方法としては特には限定されず、従来公知の任意の方法が採用されてよい。但し、多孔体の製造過程において、上記界面活性剤が水分と接触すると界面活性剤が水に溶けてしまうため、水分に接触しないようにするのが好ましい。
【００２１】
例えば、上記多孔体が連続気泡性ポリオレフィン系樹脂架橋発泡体の場合であれば、上記ポリオレフィン系樹脂及び界面活性剤に熱分解型発泡剤の他、必要に応じて架橋剤、発泡助剤等を添加し、熱分解型発泡剤が実質的に分解しない温度でバンバリーミキサー、ロール等の従来公知の方法により溶融混練し、凹金型、プレス金型等に流し込んで数分〜数十分保持することにより所定形状に成形した後、加熱して架橋発泡させ、得られた架橋発泡体に機械的変形を加えて気泡を連通させ、その後さらに連通孔を拡大させる方法が挙げられる。また、上記多孔体が繊維体の場合であれば、ポリオレフィン系樹脂及び界面活性剤を溶融混練した後、繊維状に押出し、該繊維をカードマシン等に供給して不織布を形成する方法等が挙げられる。
【００２２】
上記熱分解型発泡剤としては特には限定されず、従来公知の任意のものが使用されてよく、例えば、アゾジカルボンアミド、アゾビスイソブチロニトリル、ｐ−トルエンスルホニルヒドラジド、ジニトロソペンタメチレンテトラミン、４，４‘−オキシビスベンゼンスルホニルヒドラジド等が挙げられ、これらは単独で使用しても２種以上併用してもよい。中でも、アゾジカルボンアミドが、発生ガス量、取り扱いの安全性等に優れているので好ましい。熱分解型発泡剤の添加量は、得られる連続気泡性発泡体の所望の見掛け密度に応じて適宜調整されるが、一般には、上記ポリオレフィン系樹脂１００重量部に対し、５〜３０重量部が好ましい。
【００２３】
上記架橋剤としては特には限定されず、従来公知の任意のものが使用されてよく、例えば、ジクミルパーオキサイド、１，１−ビス（ｔ−ブチルパーオキシ）−３，３，５−トリメチルシクロヘキサン、ジ−ｔ−ブチルパーオキサイド、２，５−ジメチル−２，５−ジ（ｔ−ブチルパーオキシ）ヘキセン−３等の有機過酸化物が挙げられ、これらは単独で使用しても２種以上併用してもよい。架橋剤の添加量は、所望のゲル分率に応じて適宜調整されるが、一般には、上記ポリオレフィン系樹脂１００重量部に対し、０．２〜１．５重量部が好ましい。
【００２４】
また、上記架橋剤を添加せず、上記ポリオレフィン系樹脂にシラン化合物をグラフトしてポリオレフィン系樹脂を予め架橋性のものにしておく方法、電離性放射線照射する方法等により架橋を施すようにしてもよい。上記シラン化合物としては特には限定されず、従来公知の任意のものが使用されてよく、例えば、ビニルトリメトキシシラン、ビニルトリエトキシシラン、ビニルジメトキシシラン、ビニルジエトキシシラン、３−メタクリロキシプロピルトリエトキシシラン等が挙げられる。上記電離性放射線としては、例えば、電子線、α線、β線、γ線等が挙げられ、その照射量は適宜調整してよい。
【００２５】
上記発泡助剤としては特には限定されず、従来公知の任意のものが使用されてよく、例えば、酸化亜鉛、尿素又はその誘導体、ステアリン酸マグネシウム、ステアリン酸亜鉛等が挙げられ、これらは単独で使用しても２種以上併用してもよい。発泡助剤は上記熱分解型発泡剤の分解温度、分解速度等を調整するものであり、その添加量は製造条件、発泡剤量、得られる連続気泡性発泡体の気泡の大きさ等に応じて適宜調整される。さらに、上記ポリオレフィン系樹脂には、滑剤、顔料等の従来公知の任意の添加剤を必要に応じて適宜添加してもよい。
【００２６】
上記架橋発泡体に機械的変形を加えて気泡を連通させる方法としては、例えば、架橋発泡体の厚さよりもクリアランスの狭い１対のロール間に、架橋発泡体を通過させる方法が挙げられる。ロール間のクリアランス、ロールの速比、架橋発泡体をロールに通す回数等は適宜調整してよい。尚、上記機械的変形により架橋発泡体の気泡を連通させても、その連通孔は微細であることが多く、透気度が後述する範囲になり難いので、気泡の連通孔を拡大させるのが好ましい。
【００２７】
上記気泡の連通孔を拡大させる方法としては、例えば、架橋発泡体を密閉容器に充填し、密閉容器内を十分に脱気した後、密閉容器内に酸素ガス及び可燃ガスを注入して、酸素ガス及び可燃ガスに点火する方法が挙げられる。この気泡の連通孔を拡大させる方法は連続気泡性ポリオレフィン系樹脂架橋発泡体の場合に限られず、連続気泡性ポリウレタン系樹脂発泡体、連続気泡性セルロール系樹脂発泡体等の場合にも適用することができる。
【００２８】
上記密閉容器としては、架橋発泡体を充填可能であり、内部を真空の状態にし得るものであれば特には限定されず、その形状、大きさ等は適宜決定してよい。密閉容器を脱気する方法としては、例えば、密閉容器に真空ポンプを取り付け、真空ポンプにより密閉容器内部の空気をひく方法が挙げられる。
【００２９】
密閉容器に酸素ガス及び可燃ガスを注入する方法としては特には限定されず、例えば、酸素ガス及び可燃ガスを充填した高圧ボンベから、減圧弁で所望の混合比に見合う分圧に調整して、ガス混合ミキサーを通して密閉容器に注入する方法、酸素ガス及び可燃ガスを充填した高圧ボンベから、減圧弁で所望の混合比に見合う分圧に調整して、各々別の注入口から注入する方法等が挙げられる。尚、ガス注入直後は密閉容器内のガス分散状態が不均一なので、注入後に数分間放置しておくのが好ましい。
【００３０】
上記可燃ガスとしては、酸素ガスの存在下で燃焼可能なものであれば特には限定されず、例えば、水素ガス、メタンガス、プロパンガス等が挙げられる。
【００３１】
上記酸素ガス及び可燃ガスの混合比は、点火した際、燃焼可能な範囲であれば特には限定されないが、完全燃焼比前後であるのが好ましい。例えば、可燃ガスとして水素ガスを使用する場合では、酸素ガス：水素ガスが体積比（圧力比）で１：２前後であるのが好ましい。
【００３２】
密閉容器に充填された酸素ガス及び可燃ガスの圧力は、低くなると点火した際の気泡の連通孔の拡大が不十分で、得られる多孔体の透気度が上記範囲になり難く、得られる微生物繁殖用担持体内部の空気が水中で抜け難く、また、内部に曝気の空気泡を保持し易くなり、高くなると、点火した際、発泡体が燃焼熱により収縮し易くなるので、例えば、酸素ガス：水素ガスが体積比（圧力比）で１：２の可燃ガスの場合では、０．０３〜０．２０ＭＰａが好ましく、より好ましくは０．０５〜０．１０ＭＰａである。
【００３３】
尚、上記酸素ガス及び可燃ガスの圧力が上記範囲内にあれば、その他の不活性ガスが混在していてもよい。不活性ガスとしては、例えば、窒素ガス、ヘリウムガス、アルゴンガス、炭酸ガス等が挙げられ、これらは単独で使用しても２種以上併用してもよい。
【００３４】
上記酸素ガス及び可燃ガスを密閉容器に注入した後、点火する方法としては、例えば、予め密閉容器内にスパークスイッチを設置しておき、スパークさせる方法等が挙げられる。
【００３５】
また、上記多孔体が連続気泡性発泡体である場合、その平均気泡径は、小さくなると通気性及び吸水性が低下し、得られる微生物繁殖用担持体の内部の空気が水中で抜け難く、処理能力が低下し、さらに、微生物が付着し、繁殖した場合でも目詰まりして微生物繁殖用担持体内部で水が自由に移動でき難くなり、酸素を含む水が内部にまで到達せずに微生物が死滅してしまい易く、大きくなると、得られる微生物繁殖用担持体の体積あたりの水との接触面積が少なくなり、それにより微生物が付着する領域が減り、処理能力が低下するので、連続気泡性発泡体の断面における長さ２５ｍｍの直線上にかかる平均気泡数は６〜８０個が好ましく、より好ましくは２０〜４０個であり、さらに好ましくは１５〜２５個である。
【００３６】
上記平均気泡数は以下の方法により測定した値である。まず、連続気泡性発泡体を任意の部分で厚さ方向に切断し、さらに、前記切断面をｘｙ面とした場合、ｙｚ面及びｚｘ面が断面となる方向に切断し、その各断面と２５ｍｍの寸法目盛りとを、同一画面上に電子顕微鏡により写真撮影し、約１０倍に拡大された写真を撮る。得られた写真の任意部分に、写真内の２５ｍｍの寸法目盛りと同一長さの直線を引き、該直線にかかる気泡の個数を数え、各断面での気泡の個数を平均したものが平均気泡数である。
【００３７】
尚、本発明でいう気泡とは、気泡膜の連通の有無は問わず、写真撮影断面にある気泡膜で囲まれている部分を１つの気泡とする。上記写真撮影の際、連続気泡性発泡体の断面をマジックインキなどの着色剤で着色した後に写真撮影を行うのが、気泡の判別がし易くなるので好ましい。
【００３８】
上記連続気泡性発泡体の見掛け密度は、小さくなると変形し易くなり、得られる微生物繁殖用担持体に微生物が付着しても微生物が剥離し易くなり、大きくなると得られる微生物繁殖用担持体の体積あたりの表面積が少なくなり、処理能力が低下するので、０．０１〜０．２０ｇ／ｃｍ³が好ましく、より好ましくは０．０２〜０．０６ｇ／ｃｍ³である。
上記見掛け密度は、連続気泡性発泡体の重量Ｗ（ｇ）及び体積Ｄ（ｃｍ³）を測定し、得られた値から以下の式により算出される。
見掛け密度（ｇ／ｃｍ³）＝Ｗ（ｇ）／Ｄ（ｃｍ³）
【００３９】
本発明１の微生物繁殖用担持体は上記多孔体よりなる。該微生物繁殖用担持体の面積３１４ｍｍ²、厚さ１０ｍｍの部分に、５．５６Ｎの空気圧を厚さ方向にかけた際、５０ｃｍ3の空気が透過する時間（以下、この時間を「透気度」と記す）が、長くなると通気性及び吸水性が低下し、微生物繁殖用担持体の内部で水が自由に移動でき難くなり、処理効率が低下するので、１０秒以下であるのが好ましく、より好ましくは５秒以下である。
【００４０】
上記透気度は、Ｂ型ガーレ式デンソメーター（東洋精機製作所製）を用いて測定した値である。具体的には、微生物繁殖用担持体の任意部分から厚さ１０ｍｍの試料を採取し、該試料を３１４ｍｍ²の円孔を有する２つの締付板の間に、試料の厚さ方向を締め付けるようにして挟み、Ｂ型ガーレ式デンソメーターにセットする。デンソメーターにセットした試料の一方は開放されており、他方は閉鎖された気密空間となっている。次に、試料に接触しないように気密空間側から５．５６Ｎの空気圧を試料厚さ方向にかけ、その際、５０ｃｍ³の空気が試料を通過するのに要した時間（透気度）を測定する。尚、多孔体の厚さが１０ｍｍに満たない場合には積層して測定する。
【００４１】
次に、本発明２について説明する。本発明２で使用される多孔体としては、樹脂に界面活性剤が配合されていない以外は本発明１と同様のものが挙げられる。
【００４２】
本発明２においては、上記多孔体に上記式（１）〜（４）の何れかで示される界面活性剤が塗布又は含浸される。
【００４３】
上記式（１）〜（４）の何れかで示される界面活性剤としては、本発明１と同様のものが挙げられ、その塗布量又は含浸量が、少なくなると得られる微生物繁殖用担持体の水没性が低下し、多くなると得られる微生物繁殖用担持体の使用時に泡立ちが多くなり、使用に適さなくなるので、０．４〜２０ｇ／ｍ³に限定される。
【００４４】
上記多孔体に上記界面活性剤を塗布又は含浸する方法としては特には限定されず、従来公知の任意の方法が採用されてよい。但し、界面活性剤が水分と接触すると界面活性剤が水に溶けてしまうため、水分に接触しないようにするのが好ましい。塗布方法として、例えば、ロールにより塗布する方法、はけにより塗布する方法等が挙げられ、塗布した後、必要に応じて乾燥工程を設けてもよい。含浸方法としては、例えば、界面活性剤を含有する溶液に多孔体を浸し、その後乾燥させて溶媒を除去する方法等が挙げられる。
【００４５】
本発明２の微生物繁殖用担持体の透気度は、長くなると通気性及び吸水性が低下し、微生物繁殖用担持体の内部で水が自由に移動でき難くなり、処理効率が低下するので、１０秒以下であるのが好ましく、より好ましくは５秒以下である。
【００４６】
【実施例】
以下に実施例を挙げて本発明をさらに詳しく説明するが、本発明はこれら実施例のみに限定されるものではない。
【００４７】
（実施例１）
見掛け密度が０．０３６ｇ／ｃｍ³の連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体（長さ２５ｍｍの直線上にかかる平均気泡数３６個）を、５０重量％濃度のジ−２−エチルヘキシルスルホコハク酸エステルナトリウム塩水溶液に浸し、含浸させた後取り出して乾燥させた。次に、連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体を一対のロール間に通してしごき、ジ−２−エチルヘキシルスルホコハク酸エステルナトリウム塩の残存量を３．６ｇ／ｍ³とし、さらに８０℃のギヤオーブン中で乾燥させ、微生物繁殖用担持体を得た。得られた微生物繁殖用担持体の透気度は０．８秒であった。
【００４８】
（実施例２）
連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体を、見掛け密度が０．０４ｇ／ｃｍ³の連続気泡性ポリウレタン発泡体（長さ２５ｍｍの直線上にかかる平均気泡数３７個）にかえた以外は実施例１と同様にして微生物繁殖用担持体を得た。得られた微生物繁殖用担持体の透気度は０．５秒であった。
【００４９】
（実施例３）
連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体を、見掛け密度が０．１０ｇ／ｃｍ³のポリエチレンテレフタレート繊維からなる不織布にかえた以外は実施例１と同様にして微生物繁殖用担持体を得た。得られた微生物繁殖用担持体の透気度は０．４秒であった。
【００５０】
（実施例４）
見掛け密度が０．０４１ｇ／ｃｍ³の連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体（長さ２５ｍｍの直線上にかかる平均気泡数３６個）に、ジ−２−エチルヘキシルスルホコハク酸エステルナトリウム塩を噴霧器により、一面の塗布量が１．８ｇ／ｍ³になるように両面に塗布し、微生物繁殖用担持体を得た。得られた微生物繁殖用担持体の透気度は０．６秒であった。
【００５１】
（実施例５）
酢酸ビニル含有量が９重量％、密度が０．９４０ｇ／ｃｍ³のエチレン−酢酸ビニル共重合体１００重量部、ステアリル−２−エチルヘキシルスルホコハク酸エステルナトリウム１重量部、アゾジカルボンアミド１３重量部、ジクミルパーオキサイド０．８重量部及びステアリン酸亜鉛０．３重量部を、バンバリーミキサーにより約１２５℃で溶融混練した後、縦１６０ｍｍ×横１００ｍｍ×深さ２５ｍｍの凹型金型に充填し、約１４０℃で２０分間保持し、成形体を得た。得られた成形体を約１７０℃に加熱された縦５００ｍｍ×横５００ｍｍ×深さ８０ｍｍの凹型金型に移し、該金型内に約１００分間保持して発泡させ、エチレン−酢酸ビニル共重合体架橋発泡体を得た。
【００５２】
次に、得られたエチレン−酢酸ビニル共重合体架橋発泡体を冷却した後、クリアランスが６ｍｍの１対のロール間に２０回通し、圧縮変形によりその気泡を連通させ、さらに、表面のスキン層を除去した後、１辺が３００ｍｍの立方体状の密閉容器に入れ、該密閉容器内の圧力を真空ポンプにより０，００７ＭＰａにした。その後、酸素ガス：水素ガスが体積比で１：２に混合された混合ガスを０．１ＭＰａになるように密閉容器内に注入し、スパークプラグで点火して密閉容器内の混合ガスを燃焼させ、連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体を取り出し、微生物繁殖用担持体を得た。尚、連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体の長さ２５ｍｍの直線上にかかる平均気泡数は５５個であり、微生物繁殖用担持体の透気度は０．７秒であった。
【００５３】
（実施例６）
ステアリル−２−エチルヘキシルスルホコハク酸エステルナトリウムの配合量を０．２重量部にした以外は実施例５と同様にして微生物繁殖用担持体を得た。尚、連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体の長さ２５ｍｍの直線上にかかる平均気泡数は３６個であり、微生物繁殖用担持体の透気度は０．８秒であった。
【００５４】
（実施例７）
ステアリル−２−エチルヘキシルスルホコハク酸エステルナトリウムの配合量を４重量部にした以外は実施例５と同様にして微生物繁殖用担持体を得た。尚、連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体の長さ２５ｍｍの直線上にかかる平均気泡数は８個であり、微生物繁殖用担持体の透気度は０．３秒であった。
【００５５】
（実施例８）
見掛け密度が０．０３５ｇ／ｃｍ³、縦５０ｃｍ×横５０ｃｍ×厚さ１ｃｍの連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体（長さ２５ｍｍの直線上にかかる平均気泡数３４個）を、７５重量％濃度のジ−２−エチルヘキシルスルホコハク酸エステルナトリウム塩水溶液に浸し、ロールで押し潰しながら含浸させた後取り出して乾燥させた。次に、連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体を一対のロール間に通してしごき、ジ−２−エチルヘキシルスルホコハク酸エステルナトリウム塩の残存量を２．０ｇ／ｍ³とし、さらに８０℃のギヤオーブン中で乾燥させ、微生物繁殖用担持体を得た。得られた微生物繁殖用担持体の透気度は０．８秒であった。
【００５６】
（実施例９）
見掛け密度が０．０３４ｇ／ｃｍ³、縦５０ｃｍ×横５０ｃｍ×厚さ１ｃｍの連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体（長さ２５ｍｍの直線上にかかる平均気泡数３４個）を、７５重量％濃度のジイソプロピルナフタレンスルホン酸ナトリウム塩水溶液に浸し、ロールで押し潰しながら含浸させた後取り出して乾燥させた。次に、連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体を一対のロール間に通してしごき、ジイソプロピルナフタレンスルホン酸ナトリウム塩の残存量を２．０ｇ／ｍ³とし、さらに８０℃のギヤオーブン中で乾燥させ、微生物繁殖用担持体を得た。得られた微生物繁殖用担持体の透気度は０．８秒であった。
【００５７】
（実施例１０）
見掛け密度が０．０３５ｇ／ｃｍ³、縦５０ｃｍ×横５０ｃｍ×厚さ１ｃｍの連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体（長さ２５ｍｍの直線上にかかる平均気泡数３４個）を、７５重量％濃度のイソプロピルベンゼンスルホン酸ナトリウム塩水溶液に浸し、ロールで押し潰しながら含浸させた後取り出して乾燥させた。次に、連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体を一対のロール間に通してしごき、イソプロピルベンゼンスルホン酸ナトリウム塩の残存量を２．０ｇ／ｍ³とし、さらに８０℃のギヤオーブン中で乾燥させ、微生物繁殖用担持体を得た。得られた微生物繁殖用担持体の透気度は０．７秒であった。
【００５８】
（実施例１１）
見掛け密度が０．０３６ｇ／ｃｍ³、縦５０ｃｍ×横５０ｃｍ×厚さ１ｃｍの連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体（長さ２５ｍｍの直線上にかかる平均気泡数３４個）を、７５重量％濃度の２−エチルヘキシルエトキシサルフェートナトリウム塩水溶液に浸し、ロールで押し潰しながら含浸させた後取り出して乾燥させた。次に、連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体を一対のロール間に通してしごき、２−エチルヘキシルエトキシサルフェートナトリウム塩の残存量を２．０ｇ／ｍ³とし、さらに８０℃のギヤオーブン中で乾燥させ、微生物繁殖用担持体を得た。得られた微生物繁殖用担持体の透気度は０．７秒であった。
【００５９】
（比較例１）
見掛け密度が０．０３８ｇ／ｃｍ³の連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体（長さ２５ｍｍの直線上にかかる平均気泡数３８個）を微生物繁殖用担持体とした。得られた微生物繁殖用担持体の透気度は０．５秒であった。
【００６０】
（比較例２）
連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体として見掛け密度が０．０３０ｇ／ｃｍ³の連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体（長さ２５ｍｍの直線上にかかる平均気泡数３４個）を使用し、ジ−２−エチルヘキシルスルホコハク酸エステルナトリウム塩の残存量を６．０ｇ／ｍ³とした以外は実施例１と同様にして微生物繁殖用担持体を得た。得られた微生物繁殖用担持体の透気度は０．５秒であった。
【００６１】
（比較例３）
ジ−２−エチルヘキシルスルホコハク酸エステルナトリウム塩の残存量を０．０５ｇ／ｍ³とした以外は実施例２と同様にして微生物繁殖用担持体を得た。得られた微生物繁殖用担持体の透気度は０．５秒であった。
【００６２】
（比較例４）
ジ−２−エチルヘキシルスルホコハク酸エステルナトリウム塩の残存量を７ｇ／ｍ²とした以外は実施例２と同様にして微生物繁殖用担持体を得た。得られた微生物繁殖用担持体の透気度は０．５秒であった。
【００６３】
（比較例５）
実施例と同様のポリエチレンテレフタレート繊維からなる不織布連続気泡性エチレン−酢酸ビニル共重合体架橋発泡体を１ｃｍ角の立方体状にカットして微生物繁殖用担持体を得た。得られた微生物繁殖用担持体の透気度は０．４秒であった。
【００６４】
実施例及び比較例で得られた微生物繁殖用担持体から、１ｃｍ角の立方体状の試料を切り出し、該試料を用いて以下の評価を行い、結果を表１及び表２に示した。
【００６５】
水没性
試料を２００個用意し、該試料を、縦２０ｃｍ×横２０ｃｍ×深さ３０ｃｍのコンクリートスラブ製の水槽に入れた蒸留水６ｌの水面に静かに置いた。その後放置し、１時間後に水没性を目視により評価した。尚、試料が水面より１ｍｍ以上出ているものを浮上しているものとした。また、浮上している試料が０個になるまでの時間を測定した。
○：浮上している試料はなかった
△：浮上している試料が１〜９個であった
×：浮上している試料が１０個以上であった
【００６６】
微生物付着性、泡立ち性
試料を１０００個用意して１００個ずつ網状袋に入れ、該網状袋１０個と少量の微生物（活性汚泥）を、縦２０ｃｍ×横２０ｃｍ×深さ４０ｃｍのアクリル系樹脂製の水槽に入れた約２０℃のグルコース水溶液（グルコース濃度は約１ｍｇ／ｃｍ³）１０ｌ中に投入した。その後、水槽底面より１．５ｌ／分で曝気し続け、泡立ちの有無を目視により観察するとともに、１４日経過後及び３０日経過後に網状袋を取り出した。次に、網状袋から１０個の試料を取り出し、取り出した１０個の試料を蒸留水８０ｃｍ³中に入れ、ピンセットで試料を数回絞り、試料に付着した微生物を剥離した。さらに、別の蒸留水８０ｃｍ³中に入れ、前記と同様にして試料を絞り、試料に付着した微生物を剥離した。その後、さらに別の蒸留水８０ｃｍ³中に入れ、前記と同様にして試料を絞り、試料に付着した微生物を剥離した後、超音波振動を与え、微生物を試料から略完全に剥離した。微生物が剥離分散した蒸留水（８０ｃｍ³×３）を一つにまとめ（以下、「分散液」と記す）、該分散液の濃度を光線透過により測定し、予め検量しておいた濁度と微生物分散濃度との関係から、分散液の微生物濃度を求め、分散液中の微生物量（試料１０個に付着していた微生物量）を算出した。尚、泡立ち性は以下の通り評価した。
◎：泡は発生しなかった
○：泡が発生したが、発生から１時間以内になくなった
△：泡が発生し、発生から１時間を超え、１日以内になくなった
×：泡が発生し、発生から１日を経過してもなくならなかった
【００６７】
耐摩耗性
試料を１０個用意し、該試料の合計乾燥重量Ｗ₁（ｍｇ）を測定した。次に２０ｃｍ×横２０ｃｍ×深さ３０ｃｍのコンクリートスラブ製の水槽に蒸留水６ｌを入れ、その中に試料１０個を投入した。その後、攪拌機で３００回転／分で攪拌し続け、３０日経過後に試料を取り出し、その合計乾燥重量Ｗ₂（ｍｇ）を測定した。得られた値から、以下の式により重量減少率を算出し、以下の通り評価した。
重量減少率（重量％）＝｛（Ｗ₁−Ｗ₂）／Ｗ₁｝×１００
○：重量減少率が２重量％未満
△：重量減少率が２重量％以上５重量％未満
×：重量減少率が５重量％以上
【００６８】
【表１】

【００６９】
【表２】

【００７０】
【発明の効果】
本発明の微生物繁殖用担持体は、通気性及び通水性に優れ、処理槽等の水中に投入された際の水没性に優れるとともに、泡立ちが少なく、速やかに処理能力を発揮することができるとともに、微生物による目詰まりが生じ難い。また、耐摩耗性に優れており、長期にわたり優れた処理能力を維持することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a microorganism propagation carrier excellent in submergence.
[0002]
[Prior art]
Conventionally, the aeration method and activated sludge method are generally used in the treatment of sewage treatment tanks for domestic and industrial wastewater, combined septic tanks, garbage disposers, biological deodorizers, etc. In recent years, there has been a problem that the reduction of nitrogen, phosphorus, etc., which cause red tide, is insufficient, and in recent years, processing methods that effectively use microorganisms to reduce the size of equipment as much as possible and further improve the processing capacity have been studied. Has been.
[0003]
In the treatment method using the microorganism, it is effective to use a support for propagating the microorganism. A porous body is used as the carrier, and when it is put into the treatment tank, it begins to submerge in water and the microorganisms start to propagate. Examples of the porous material used for the carrier include continuous cells made of polyurethane-based resin or cellulose-based resin in addition to the open-cell polyolefin-based resin crosslinked foam as described in JP-A-57-191027. Examples thereof include a cellular foam, a fiber body obtained by agglomerating and fusing fibers made of polyolefin resin or polyester resin, and a granular gel made of polyethylene glycol or polyvinyl alcohol.
[0004]
However, since the porous body is often made of a material having poor hydrophilicity, it is difficult for the air inside the porous body to escape, so it takes about 1 to 3 weeks to completely submerge after being put into the treatment tank, Furthermore, there is a problem that it takes about one month before the processing capability is exhibited.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a carrier for microbial propagation that is excellent in submergence when thrown into a treatment tank and can quickly exhibit the treatment ability.
[0006]
[Means for Solving the Problems]
The carrier for microbial propagation of the invention according to claim 1 of the present invention (hereinafter referred to as “present invention 1”) comprises 100 parts by weight of polyolefin resin and the following formulas (1) to ( 4 ) Is a porous body composed of 0.1 to 5 parts by weight of a surfactant.
[0007]
[Chemical 9]

(In formula (1), R ₁ And R ₂ Is an alkyl group and M is Na, K, Mg, Zn or NH _Three Is)
[0008]
[Chemical Formula 10]

(In formula (2), R _Three And R _Four Is hydrogen or an alkyl group and M is Na, K, Mg, Zn or NH _Three Is)
[0009]
Embedded image

(In formula (3), R _Five Is hydrogen or an alkyl group and M is Na, K, Mg, Zn or NH _Three Is)
[0010]
Embedded image

(In formula (4), R ₆ And R ₇ Is hydrogen or an alkyl group and M is Na, K, Mg, Zn or NH _Three And n1 is a natural number)
[0011]
The microorganism propagating support of the invention according to claim 2 of the present invention (hereinafter referred to as “present invention 2”) is formed on a porous body made of a polyolefin-based resin by the above formulas (1) to ( 4 ) In a range of 0.4 to 20 g / m. ^Three It is applied or impregnated so that
[0012]
First, the present invention 1 will be described. The porous body used in the present invention 1 is a polyolefin resin and the above formulas (1) to ( 4 ), And the form thereof is not particularly limited, and examples thereof include open-cell foams, fiber bodies, and granular gels. Among them, an open-cell foam is preferable because it is not defibrated, has a large surface area per volume, and is excellent in the propagation efficiency of microorganisms.
[0013]
As the resin constituting the porous body, a polyolefin-based resin is used, and when the porous body is an open-celled foam, it is preferably crosslinked.
[0014]
Examples of the polyolefin resin include ethylene-α-olefin copolymers mainly composed of ethylene such as low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, and the like. Ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer based on ethylene, polypropylene, propylene-α-olefin copolymer based on propylene, ethylene-propylene-butene based on propylene A terpolymer, polybutene, etc. are mentioned, These may be used individually or may be used together 2 or more types. Examples of the α-olefin constituting the ethylene-α-olefin copolymer include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene and the like. Examples of the α-olefin constituting the propylene-α-olefin copolymer include ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene and the like can be mentioned.
[0015]
Further, the specific gravity of the polyolefin resin is often smaller than that of water, and when a porous body obtained from the resin is used as a support for microbial propagation, even if water completely penetrates into the inside, it depends on aeration conditions. Since it may be difficult to submerge and the initial underwater floating fluidity is lowered, an inorganic filler may be added.
[0016]
Examples of the inorganic filler include calcium carbonate, talc, barium sulfate, aluminum hydroxide, and zeolite. These may be used alone or in combination of two or more. When the amount of the inorganic filler is reduced, the effect of addition cannot be obtained, and when the amount is increased, foaming is difficult at the foaming stage. Therefore, the amount is preferably 10 to 80 parts by weight, more preferably 100 parts by weight of the polyolefin resin. It is preferably 20 to 60 parts by weight and adjusted so that the specific gravity of the resin after addition of the inorganic filler is equal to or slightly larger than that of water.
[0017]
Specific examples of the surfactant represented by the above formula (1) include n-paraffin-2- such as di-2-ethylhexylsulfosuccinate sodium salt and stearyl-2-ethylhexylsulfosuccinate sodium salt. Ethylhexyl sulfosuccinate sodium salt and the like are preferable. Specifically, as the surfactant represented by the above formula (2), for example, di-isopropylnaphthalenesulfonic acid sodium salt is preferable.
[0018]
Specifically, as the surfactant represented by the above formula (3), for example, sodium isopropylbenzenesulfonate is preferable. Specifically, as the surfactant represented by the above formula (4), for example, 2-ethylhexyl ethoxysulfate sodium salt is preferable.
[0019]
The above formulas (1) to ( 4 Among these surfactants, the surfactant represented by the above formula (1) is particularly preferable because a carrier for microbial propagation having excellent submergence can be obtained with a small amount of addition. The above formulas (1) to ( 4 ) May be used alone or in combination of two or more. When the amount of the surfactant decreases, the submergence of the resulting microbial growth carrier decreases and increases. When the obtained support for microbial propagation is used, foaming is increased, making it unsuitable for use. Also, when the porous body is an open-cell foam, the foamability at the foaming stage of the open-cell foam is reduced. Therefore, it is limited to 0.1 to 5 parts by weight, preferably 0.2 to 2 parts by weight with respect to 100 parts by weight of the polyolefin resin. Moreover, said Formula (1)-( 4 If a surfactant other than the surfactant shown in any of (1) is used, foaming increases during use of the microorganism-growing carrier, which is not suitable for use.
[0020]
The method for obtaining the porous body from the polyolefin resin and the surfactant is not particularly limited, and any conventionally known method may be employed. However, since the surfactant dissolves in water when the surfactant comes into contact with moisture in the production process of the porous body, it is preferable not to come into contact with moisture.
[0021]
For example, if the porous body is an open-cell polyolefin-based resin cross-linked foam, in addition to the pyrolytic foaming agent, a crosslinking agent, a foaming aid, etc. may be added to the polyolefin-based resin and the surfactant. Add, melt and knead by a conventionally known method such as a Banbury mixer and roll at a temperature at which the pyrolytic foaming agent is not substantially decomposed, pour into a concave mold, a press mold, etc. and hold for several minutes to several tens of minutes There is a method in which after forming into a predetermined shape, it is heated and crosslinked to foam, the resulting crosslinked foam is subjected to mechanical deformation to allow bubbles to communicate, and then the communicating hole is further expanded. Further, when the porous body is a fibrous body, a method of forming a nonwoven fabric by melting and kneading a polyolefin resin and a surfactant and then extruding it into a fibrous form and supplying the fiber to a card machine or the like can be mentioned. It is done.
[0022]
The pyrolytic foaming agent is not particularly limited, and any conventionally known one may be used. For example, azodicarbonamide, azobisisobutyronitrile, p-toluenesulfonylhydrazide, dinitrosopentamethylenetetramine 4,4′-oxybisbenzenesulfonylhydrazide and the like, and these may be used alone or in combination of two or more. Among these, azodicarbonamide is preferable because it is excellent in the amount of generated gas, safety in handling, and the like. The amount of the pyrolytic foaming agent added is appropriately adjusted according to the desired apparent density of the obtained open-cell foamed material, but generally 5 to 30 parts by weight with respect to 100 parts by weight of the polyolefin resin. preferable.
[0023]
The crosslinking agent is not particularly limited, and any conventionally known crosslinking agent may be used. For example, dicumyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethyl Organic peroxides such as cyclohexane, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexene-3 can be mentioned, and these can be used alone. Two or more species may be used in combination. Although the addition amount of a crosslinking agent is suitably adjusted according to a desired gel fraction, generally 0.2-1.5 weight part is preferable with respect to 100 weight part of said polyolefin resin.
[0024]
Further, without adding the above-mentioned crosslinking agent, crosslinking may be performed by a method of grafting a silane compound to the polyolefin-based resin to make the polyolefin-based resin crosslinkable in advance, a method of irradiating with ionizing radiation, or the like. Good. The silane compound is not particularly limited, and any conventionally known silane compound may be used. For example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyldimethoxysilane, vinyldiethoxysilane, 3-methacryloxypropyltri An ethoxysilane etc. are mentioned. Examples of the ionizing radiation include electron beams, α rays, β rays, γ rays and the like, and the irradiation amount may be adjusted as appropriate.
[0025]
The foaming aid is not particularly limited, and any conventionally known one may be used. Examples thereof include zinc oxide, urea or derivatives thereof, magnesium stearate, zinc stearate, and the like. You may use it or it may use 2 or more types together. The foaming assistant adjusts the decomposition temperature, decomposition rate, etc. of the above pyrolyzable foaming agent, and the amount added depends on the production conditions, the amount of foaming agent, the size of the cells in the resulting open cell foam, etc. Are adjusted accordingly. Furthermore, you may add suitably conventionally well-known arbitrary additives, such as a lubricant and a pigment, to the said polyolefin resin as needed.
[0026]
Examples of the method of causing the bubbles to communicate by applying mechanical deformation to the crosslinked foam include a method of passing the crosslinked foam between a pair of rolls having a clearance smaller than the thickness of the crosslinked foam. You may adjust suitably the clearance between rolls, the speed ratio of a roll, the frequency | count of passing a crosslinked foam through a roll, etc. suitably. Even if the bubbles of the crosslinked foam are communicated by the mechanical deformation, the communicating holes are often fine and the air permeability is unlikely to be in the range described later. preferable.
[0027]
As a method of expanding the communication hole of the bubbles, for example, after filling a closed container with a crosslinked foam and sufficiently degassing the inside of the sealed container, oxygen gas and combustible gas are injected into the sealed container, The method of igniting gas and combustible gas is mentioned. This method of expanding the communicating holes of the bubbles is not limited to the case of the open cell polyolefin-based resin cross-linked foam, but can also be applied to the case of the open-cell polyurethane-based resin foam, the open-celled cellulose resin foam, etc. Can do.
[0028]
The closed container is not particularly limited as long as it can be filled with a crosslinked foam and can be evacuated, and the shape, size, and the like may be appropriately determined. As a method for degassing the sealed container, for example, a method of attaching a vacuum pump to the sealed container and drawing the air inside the sealed container with the vacuum pump can be mentioned.
[0029]
The method for injecting oxygen gas and combustible gas into the sealed container is not particularly limited.For example, from a high-pressure cylinder filled with oxygen gas and combustible gas, the partial pressure is adjusted to a desired mixing ratio with a pressure reducing valve, A method of injecting into a closed container through a gas mixing mixer, a method of adjusting from a high-pressure cylinder filled with oxygen gas and combustible gas to a partial pressure corresponding to a desired mixing ratio with a pressure reducing valve, and injecting from each different inlet, etc. Can be mentioned. Since the gas dispersion state in the sealed container is not uniform immediately after gas injection, it is preferable to leave it for several minutes after injection.
[0030]
The combustible gas is not particularly limited as long as it is combustible in the presence of oxygen gas, and examples thereof include hydrogen gas, methane gas, and propane gas.
[0031]
The mixing ratio of the oxygen gas and the combustible gas is not particularly limited as long as it can be combusted when ignited, but is preferably around the complete combustion ratio. For example, when hydrogen gas is used as the combustible gas, it is preferable that the oxygen gas: hydrogen gas ratio is about 1: 2 in volume ratio (pressure ratio).
[0032]
If the pressure of the oxygen gas and the combustible gas filled in the sealed container is low, the expansion of the bubble communication holes when ignited is insufficient, and the air permeability of the obtained porous body is unlikely to be in the above range, and the resulting microorganism The air inside the breeding carrier is difficult to escape in the water, and it is easy to hold the aerated air bubbles inside. If it becomes high, the foam tends to shrink due to the combustion heat when ignited. When hydrogen gas is a combustible gas with a volume ratio (pressure ratio) of 1: 2, 0.03 to 0.20 MPa is preferable, and 0.05 to 0.10 MPa is more preferable.
[0033]
In addition, if the pressure of the said oxygen gas and combustible gas exists in the said range, the other inert gas may be mixed. Examples of the inert gas include nitrogen gas, helium gas, argon gas, carbon dioxide gas, etc., and these may be used alone or in combination of two or more.
[0034]
Examples of the method of igniting after injecting the oxygen gas and the combustible gas into the sealed container include a method in which a spark switch is previously installed in the sealed container and sparked.
[0035]
Further, when the porous body is an open-cell foam, when the average cell diameter becomes small, the air permeability and water absorption decrease, and the air inside the obtained microbial growth support is difficult to escape in water, and the treatment Even if microorganisms adhere and propagate, clogging occurs, making it difficult for water to move freely inside the microorganism propagating support, and oxygen-containing water does not reach the interior and the microorganisms do not reach the interior. Open cell foam is easy to die, and when it becomes large, the contact area with the water per volume of the resulting microbial propagation carrier is reduced, thereby reducing the area to which microorganisms adhere and reducing the treatment capacity. The average number of bubbles applied on a straight line having a length of 25 mm in the cross section of the body is preferably 6 to 80, more preferably 20 to 40, and even more preferably 15 to 25.
[0036]
The average number of bubbles is a value measured by the following method. First, the open-cell foam is cut in the thickness direction at an arbitrary portion, and further, when the cut surface is an xy plane, the yz plane and the zx plane are cut in the direction of the cross section, and each cross section is 25 mm. Are taken with an electron microscope on the same screen, and a photograph magnified about 10 times is taken. The average number of bubbles is obtained by drawing a straight line of the same length as the 25-mm dimension scale in the photograph and counting the number of bubbles on the straight line and averaging the number of bubbles in each section. It is.
[0037]
In the present invention, the bubble refers to a portion surrounded by the bubble film in the cross section of the photograph, regardless of whether the bubble film is connected or not. At the time of the above photographing, it is preferable to photograph after the cross section of the open-cell foam is colored with a colorant such as magic ink because it is easy to distinguish the bubbles.
[0038]
The apparent density of the open-cell foamed material is likely to be deformed when it becomes small, and even if microorganisms adhere to the resulting microbial propagation carrier, the microorganisms are easy to peel off. Since the surface area per area decreases and the processing capacity decreases, 0.01 to 0.20 g / cm ^Three Is preferable, and more preferably 0.02 to 0.06 g / cm. ^Three It is.
The apparent density is the weight W (g) and volume D (cm) of the open-cell foam. ^Three ) And is calculated from the obtained value according to the following formula.
Apparent density (g / cm ^Three ) = W (g) / D (cm ^Three )
[0039]
The carrier for propagation of microorganisms of the present invention 1 comprises the above porous body. The area of the carrier for propagating microorganisms is 314 mm. ² When the air pressure of 5.56 N is applied to the 10 mm thick part in the thickness direction, the air permeation and water absorption will increase if the time required for 50 cm 3 air to permeate (hereinafter referred to as “air permeability”) becomes longer. It is preferably 10 seconds or less, and more preferably 5 seconds or less, because the properties are reduced, and it becomes difficult for water to move freely inside the microorganism propagation carrier and the treatment efficiency is lowered.
[0040]
The air permeability is a value measured using a B-type Gurley type densometer (manufactured by Toyo Seiki Seisakusho). Specifically, a sample having a thickness of 10 mm is taken from an arbitrary portion of the microorganism-growing carrier, and the sample is 314 mm. ² The sample is sandwiched between two clamping plates having circular holes so that the thickness direction of the sample is clamped, and set in a B-type Gurley densometer. One of the samples set in the densometer is open and the other is a closed airtight space. Next, an air pressure of 5.56 N is applied in the sample thickness direction from the airtight space side so as not to contact the sample, and at that time, 50 cm ^Three The time (air permeability) required for the air to pass through the sample is measured. When the thickness of the porous body is less than 10 mm, measurement is performed by laminating.
[0041]
Next, the present invention 2 will be described. Examples of the porous body used in the present invention 2 include those similar to the present invention 1 except that a surfactant is not blended in the resin.
[0042]
In the second aspect of the present invention, the above-described formulas (1) to ( 4 ) Is applied or impregnated.
[0043]
The above formulas (1) to ( 4 As the surfactant shown in any of the above, the same as in the present invention 1 can be mentioned, and when the coating amount or impregnation amount is reduced, the submergence of the obtained microorganism propagation carrier is decreased and increased. Foaming increases during use of the resulting microbial growth carrier, making it unsuitable for use, so 0.4-20 g / m ^Three It is limited to.
[0044]
The method for applying or impregnating the surfactant to the porous body is not particularly limited, and any conventionally known method may be employed. However, since the surfactant dissolves in water when the surfactant comes into contact with moisture, it is preferable not to come into contact with moisture. Examples of the application method include a method of applying with a roll, a method of applying with a brush, and the like, and after application, a drying step may be provided as necessary. Examples of the impregnation method include a method of immersing the porous body in a solution containing a surfactant and then drying to remove the solvent.
[0045]
As the air permeability of the microorganism propagation carrier of the present invention 2 becomes longer, the air permeability and water absorption decrease, water becomes difficult to move freely inside the microorganism propagation carrier, and the processing efficiency decreases. It is preferably 10 seconds or shorter, more preferably 5 seconds or shorter.
[0046]
【Example】
EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited only to these examples.
[0047]
Example 1
Apparent density is 0.036 g / cm ^Three Of the above-mentioned open-cell ethylene-vinyl acetate copolymer crosslinked foam (average number of bubbles of 36 on a straight line having a length of 25 mm) was immersed in an aqueous solution of di-2-ethylhexylsulfosuccinate sodium salt having a concentration of 50% by weight, After impregnation, it was taken out and dried. Next, the open-celled ethylene-vinyl acetate copolymer crosslinked foam was passed through a pair of rolls, and the residual amount of di-2-ethylhexyl sulfosuccinate sodium salt was 3.6 g / m. ^Three And dried in a gear oven at 80 ° C. to obtain a support for propagation of microorganisms. The air permeability of the obtained microorganism propagation carrier was 0.8 seconds.
[0048]
(Example 2)
Open cell ethylene-vinyl acetate copolymer cross-linked foam with an apparent density of 0.04 g / cm ^Three A support for microbial propagation was obtained in the same manner as in Example 1 except that the open-cell polyurethane foam was replaced with an average cell number of 37 foams on a straight line having a length of 25 mm. The air permeability of the obtained microorganism propagation carrier was 0.5 seconds.
[0049]
(Example 3)
Open cell ethylene-vinyl acetate copolymer cross-linked foam with an apparent density of 0.10 g / cm ^Three A carrier for propagation of microorganisms was obtained in the same manner as in Example 1 except that the nonwoven fabric was made of polyethylene terephthalate fiber. The air permeability of the obtained microorganism propagation carrier was 0.4 seconds.
[0050]
(Example 4)
Apparent density 0.041g / cm ^Three An open cell ethylene-vinyl acetate copolymer cross-linked foam (average number of bubbles of 36 on a straight line having a length of 25 mm) was sprayed with di-2-ethylhexyl sulfosuccinate sodium salt using a sprayer, and the coating amount on one side was 1.8 g / m ^Three It was applied on both sides to obtain a microorganism propagation carrier. The air permeability of the obtained microorganism propagation carrier was 0.6 seconds.
[0051]
(Example 5)
Vinyl acetate content 9% by weight, density 0.940g / cm ^Three 100 parts by weight of ethylene-vinyl acetate copolymer, 1 part by weight of sodium stearyl-2-ethylhexylsulfosuccinate, 13 parts by weight of azodicarbonamide, 0.8 part by weight of dicumyl peroxide and 0.3 part by weight of zinc stearate Was melt-kneaded at about 125 ° C. with a Banbury mixer, then filled into a concave mold having a length of 160 mm × width of 100 mm × depth of 25 mm, and held at about 140 ° C. for 20 minutes to obtain a molded body. The obtained molded body was transferred to a concave mold having a length of 500 mm, a width of 500 mm, and a depth of 80 mm heated to about 170 ° C., held in the mold for about 100 minutes, and foamed, and an ethylene-vinyl acetate copolymer. A cross-linked foam was obtained.
[0052]
Next, after cooling the obtained ethylene-vinyl acetate copolymer crosslinked foam, it was passed 20 times between a pair of rolls having a clearance of 6 mm, and the bubbles were communicated by compressive deformation. Was removed and placed in a cubic airtight container having a side of 300 mm, and the pressure in the airtight container was reduced to 0.007 MPa by a vacuum pump. Thereafter, a mixed gas in which oxygen gas: hydrogen gas is mixed at a volume ratio of 1: 2 is injected into the sealed container so as to be 0.1 MPa, and the sparked plug is ignited to burn the mixed gas in the sealed container. Then, an open-celled ethylene-vinyl acetate copolymer crosslinked foam was taken out to obtain a support for propagation of microorganisms. The average number of bubbles applied on a 25 mm long straight line of the open cell ethylene-vinyl acetate copolymer cross-linked foam was 55, and the air permeability of the support for microbial propagation was 0.7 seconds. .
[0053]
(Example 6)
A microorganism propagating support was obtained in the same manner as in Example 5 except that the amount of sodium stearyl-2-ethylhexyl sulfosuccinate sodium was changed to 0.2 parts by weight. In addition, the average number of bubbles applied on a 25 mm long straight line of the open-cell ethylene-vinyl acetate copolymer crosslinked foam was 36, and the air permeability of the microorganism propagation carrier was 0.8 seconds. .
[0054]
(Example 7)
A microorganism propagating support was obtained in the same manner as in Example 5 except that the amount of stearyl-2-ethylhexyl sulfosuccinate sodium was changed to 4 parts by weight. In addition, the average number of cells applied on a straight line having a length of 25 mm of the open-cell ethylene-vinyl acetate copolymer crosslinked foam was 8, and the air permeability of the microorganism propagation carrier was 0.3 seconds. .
[0055]
(Example 8)
Apparent density is 0.035 g / cm ^Three , An open cell ethylene-vinyl acetate copolymer cross-linked foam (length 50 cm × width 50 cm × thickness 1 cm) (average number of bubbles 34 on a straight line of 25 mm in length) It was immersed in an ethylhexylsulfosuccinate sodium salt aqueous solution, impregnated while being crushed with a roll, taken out and dried. Next, the open cell ethylene-vinyl acetate copolymer cross-linked foam was passed through a pair of rolls to squeeze the residual amount of di-2-ethylhexyl sulfosuccinate sodium salt to 2.0 g / m. ^Three And dried in a gear oven at 80 ° C. to obtain a support for propagation of microorganisms. The air permeability of the obtained microorganism propagation carrier was 0.8 seconds.
[0056]
Example 9
Apparent density is 0.034 g / cm ^Three , 50 cm long x 50 cm wide x 1 cm thick open cell ethylene-vinyl acetate copolymer cross-linked foam (average number of bubbles of 34 bubbles on a straight line of 25 mm in length) was added to diisopropyl naphthalenesulfonic acid at a concentration of 75% by weight. It was immersed in an aqueous sodium salt solution, impregnated while being crushed with a roll, taken out and dried. Next, the open cell ethylene-vinyl acetate copolymer cross-linked foam was passed through a pair of rolls to squeeze the remaining amount of sodium diisopropylnaphthalenesulfonate to 2.0 g / m. ^Three And dried in a gear oven at 80 ° C. to obtain a support for propagation of microorganisms. The air permeability of the obtained microorganism propagation carrier was 0.8 seconds.
[0057]
(Example 10)
Apparent density is 0.035 g / cm ^Three , An open cell ethylene-vinyl acetate copolymer cross-linked foam (length: 50 cm × width: 50 cm × thickness: 1 cm) (average number of bubbles of 34 bubbles on a straight line of 25 mm in length) was added to 75% by weight isopropylbenzenesulfonic acid It was immersed in an aqueous sodium salt solution, impregnated while being crushed with a roll, taken out and dried. Next, the open cell ethylene-vinyl acetate copolymer cross-linked foam was passed through a pair of rolls, and the remaining amount of sodium isopropylbenzenesulfonate was 2.0 g / m. ^Three And dried in a gear oven at 80 ° C. to obtain a support for propagation of microorganisms. The air permeability of the obtained microorganism propagation carrier was 0.7 seconds.
[0058]
(Example 11)
Apparent density is 0.036 g / cm ^Three An open cell ethylene-vinyl acetate copolymer cross-linked foam (length 50 cm × width 50 cm × thickness 1 cm) (average number of bubbles 34 on a straight line having a length of 25 mm) was converted into 2-ethylhexylethoxy having a concentration of 75% by weight. It was immersed in a sulfate sodium salt aqueous solution, impregnated while being crushed with a roll, and then taken out and dried. Next, the open cell ethylene-vinyl acetate copolymer cross-linked foam was passed through a pair of rolls, and the residual amount of 2-ethylhexyl ethoxysulfate sodium salt was 2.0 g / m. ^Three And dried in a gear oven at 80 ° C. to obtain a support for propagation of microorganisms. The air permeability of the obtained microorganism propagation carrier was 0.7 seconds.
[0059]
(Comparative Example 1)
Apparent density is 0.038 g / cm ^Three An open-celled ethylene-vinyl acetate copolymer crosslinked foam (average number of bubbles of 38 on a straight line having a length of 25 mm) was used as a support for microorganism propagation. The air permeability of the obtained microorganism propagation carrier was 0.5 seconds.
[0060]
(Comparative Example 2)
Open cell ethylene-vinyl acetate copolymer crosslinked foam with an apparent density of 0.030 g / cm ^Three Using an open-cell ethylene-vinyl acetate copolymer crosslinked foam (average number of bubbles of 34 on a straight line having a length of 25 mm) and a residual amount of di-2-ethylhexyl sulfosuccinate sodium salt of 6.0 g / M ^Three A microorganism propagating support was obtained in the same manner as in Example 1 except that. The air permeability of the obtained microorganism propagation carrier was 0.5 seconds.
[0061]
(Comparative Example 3)
The residual amount of di-2-ethylhexyl sulfosuccinate sodium salt is 0.05 g / m ^Three A microorganism propagating support was obtained in the same manner as in Example 2 except that. The air permeability of the obtained microorganism propagation carrier was 0.5 seconds.
[0062]
(Comparative Example 4)
The residual amount of di-2-ethylhexyl sulfosuccinate sodium salt was 7 g / m. ² A microorganism propagating support was obtained in the same manner as in Example 2 except that. The air permeability of the obtained microorganism propagation carrier was 0.5 seconds.
[0063]
(Comparative Example 5)
A nonwoven fabric open-celled ethylene-vinyl acetate copolymer crosslinked foam made of polyethylene terephthalate fibers similar to that of the example was cut into a 1 cm square cube to obtain a microorganism propagation carrier. The air permeability of the obtained microorganism propagation carrier was 0.4 seconds.
[0064]
A 1 cm square cubic sample was cut out from the microorganism propagation carrier obtained in the examples and comparative examples, and the following evaluation was performed using the sample. Tables 1 and 2 show the results.
[0065]
Submerged
200 samples were prepared, and the samples were gently placed on the surface of 6 l of distilled water placed in a concrete slab water tank having a length of 20 cm, a width of 20 cm, and a depth of 30 cm. Then, it was allowed to stand, and after 1 hour, the submergence was visually evaluated. In addition, it was assumed that the sample protruded 1 mm or more from the water surface. Further, the time until the number of floating samples became zero was measured.
○: There was no sample floating
Δ: 1 to 9 floating samples
X: There were 10 or more floating samples
[0066]
Microbial adhesion, foaming
About 1000 samples were prepared and placed in a mesh bag, and 10 mesh bags and a small amount of microorganisms (activated sludge) were placed in an acrylic resin water tank 20 cm long x 20 cm wide x 40 cm deep. 20 ° C. glucose aqueous solution (glucose concentration is about 1 mg / cm ^Three ) Into 10 l. Thereafter, aeration was continued from the bottom of the water tank at 1.5 l / min, and the presence or absence of foaming was visually observed, and the mesh bag was taken out after 14 days and after 30 days. Next, 10 samples were taken out from the mesh bag, and the 10 samples taken out were 80 cm in distilled water. ^Three The sample was squeezed several times with tweezers to remove microorganisms attached to the sample. Furthermore, another 80cm of distilled water ^Three The sample was squeezed in the same manner as described above, and the microorganisms adhering to the sample were peeled off. Then, another distilled water 80cm ^Three Then, the sample was squeezed in the same manner as described above, and the microorganisms adhering to the sample were peeled off. Then, ultrasonic vibration was applied to remove the microorganisms from the sample almost completely. Distilled water from which microorganisms are peeled and dispersed (80 cm ^Three X3) are grouped together (hereinafter referred to as “dispersion liquid”), the concentration of the dispersion liquid is measured by light transmission, and the dispersion liquid is determined based on the relationship between the turbidity and the microorganism dispersion concentration which have been measured in advance. The microbial concentration was determined, and the amount of microorganisms in the dispersion (the amount of microorganisms adhering to 10 samples) was calculated. The foamability was evaluated as follows.
A: No bubbles were generated
○: Bubbles were generated but disappeared within 1 hour from the occurrence
Δ: Bubbles were generated and exceeded 1 hour from the occurrence and disappeared within 1 day.
X: Bubbles were generated and did not disappear even after 1 day
[0067]
Abrasion resistance
10 samples are prepared, and the total dry weight W of the samples ₁ (Mg) was measured. Next, 6 l of distilled water was put into a water tank made of concrete slab having a size of 20 cm × width 20 cm × depth 30 cm, and 10 samples were put therein. Thereafter, stirring was continued at 300 rpm with a stirrer, and a sample was taken out after 30 days, and its total dry weight W ₂ (Mg) was measured. From the obtained value, the weight loss rate was calculated by the following formula and evaluated as follows.
Weight reduction rate (% by weight) = {(W ₁ -W ₂ ) / W ₁ } × 100
○: Weight reduction rate is less than 2% by weight
Δ: Weight reduction rate is 2% by weight or more and less than 5% by weight
X: The weight reduction rate is 5% by weight or more.
[0068]
[Table 1]

[0069]
[Table 2]

[0070]
【The invention's effect】
The microorganism propagating support of the present invention is excellent in air permeability and water permeability, excellent in submergence when thrown into water such as a treatment tank, with less foaming, and can exhibit processing ability quickly. Clogging by microorganisms is difficult to occur. Moreover, it is excellent in abrasion resistance and can maintain excellent processing capacity over a long period of time.

Claims (5)

A microorganism propagation carrier comprising a porous body comprising 100 parts by weight of a polyolefin resin and 0.1 to 5 parts by weight of a surfactant represented by any of the following formulas (1) to ( 4 ).

(In formula (1), R ₁ and R ₂ are alkyl groups, and M is Na, K, Mg, Zn or NH ₃ )

(In the formula (2), R ₃ and R ₄ are hydrogen or an alkyl group, and M is Na, K, Mg, Zn or NH ₃ )

(In the formula (3), R ₅ is hydrogen or an alkyl group, and M is Na, K, Mg, Zn or NH ₃ )

(In formula (4), R ₆ and R ₇ are hydrogen or an alkyl group, M is Na, K, Mg, Zn or NH ₃ , and n 1 is a natural number) Support for microbial propagation, which is formed by applying or impregnating a porous material made of polyolefin resin so that a surfactant represented by any of the following formulas (1) to ( 4 ) is 0.4 to 20 g / m ^3. body.

(In formula (1), R ₁ and R ₂ are alkyl groups, and M is Na, K, Mg, Zn or NH ₃ )

(In the formula (2), R ₃ and R ₄ are hydrogen or an alkyl group, and M is Na, K, Mg, Zn or NH ₃ )

(In the formula (3), R ₅ is hydrogen or an alkyl group, and M is Na, K, Mg, Zn or NH ₃ )

(In formula (4), R ₆ and R ₇ are hydrogen or an alkyl group, M is Na, K, Mg, Zn or NH ₃ , and n 1 is a natural number)   The microorganism propagation carrier according to claim 1 or 2, wherein the porous body is an open-cell polyolefin resin foam.   The support for microorganism propagation according to claim 2, wherein the porous body is a fibrous body. The time in which 50 cm ³ of air permeates is 10 seconds or less when an air pressure of 5.56 N is applied in the thickness direction to a portion having an area of 314 mm ² and a thickness of 10 mm. The carrier for microbial propagation as described.