JP4149708B2

JP4149708B2 - Vaporizable solid rust inhibitor

Info

Publication number: JP4149708B2
Application number: JP2002007849A
Authority: JP
Inventors: 信義南部; 一比古有松; 寿光濱口
Original assignee: Chelest Corp; Chubu Chelest Co Ltd
Current assignee: Chelest Corp; Chubu Chelest Co Ltd
Priority date: 2002-01-16
Filing date: 2002-01-16
Publication date: 2008-09-17
Anticipated expiration: 2022-01-16
Also published as: JP2003213462A; WO2003060197A1

Description

【０００１】
【発明の属する技術分野】
本発明は気化性固形防錆剤に関し、たとえば鉄鋼材製の各種機械部品や自動車部品の如く酸化を受け易い金属からなる機器や部品等を保管し、搬送し、もしくは輸送する際に、その表面が酸化を受けて発錆するのを防止するための気化性固形防錆剤であって、特に短期および長期のいずれにおいても優れた防錆能を発揮すると共に、被防錆部品表面への付着による汚染など起こすことのない気化性固形防錆剤に関するものである。
【０００２】
【従来の技術】
上記の様な金属部材の防錆対策として従来から汎用されているのは、防錆対象となる金属部材の表面に防錆油を塗布して油膜を形成し、発錆原因となる酸素や水分を遮断する方法である。ところが防錆油を使用する方法では、用済み後の油膜の除去が煩雑であることから、最近では少量で優れた防錆効果を発揮し、しかも用済み後は簡単に除去することのできる気化性固形防錆剤が実用化され始めている。
【０００３】
この種の気化性固形防錆剤は、一般にＶＣＩ（Volatile Corrosion Inhibitor）と呼ばれており、代表的なものとしては、昇華性のシクロヘキシルアミンの炭酸塩［（Ｃ₆Ｈ₁₁ＮＨ）₂ＨＣＯ₂：ＣＨＣ］やジイソプロピルアミン亜硝酸塩｛［（ＣＨ₃）₂ＣＨ］₂ＮＨ・ＨＮＯ₂：ＤＩＰＡＮ｝、ジシクロヘキシルアミン亜硝酸塩〔（Ｃ₆Ｈ₁₁）₂ＮＨ・ＨＮＯ₂：ＤＩＣＨＡＮ〕等が知られている。
【０００４】
ところがＣＨＣは、優れた初期防錆能は発揮するものの臭気が強く、またその蒸気圧は４×１０^-1ｍｍＨｇ（２５℃）と高いため、長期防錆を発揮させるには包装形態を厳重に行なわねばならない。一方ＤＩＣＨＡＮは、長期防錆能には優れているものの、蒸気圧が１×１０^-4ｍｍＨｇ（２５℃）と低く、防錆効果を発揮するのに２０時間以上を要するため初期防錆能に欠ける。また、防錆対象物品からの距離が２０〜３０ｃｍ以上離れると十分な防錆効果が発揮されない。
【０００５】
また、ＤＩＰＡＮの蒸気圧は５×１０^-3ｍｍＨｇ（２５℃）でＣＨＣとＤＩＣＨＡＮの中間であり、優れた初期防錆能と長期防錆能を兼ね備えているが、これを大気中に放置すると、その一部が変質してジイソプロピル−Ｎ−ニトロソアミンを生成することが知られており、該ジイソプロピル−Ｎ−ニトロソアミンは、発癌性を有すること（H.DRUCKRW,R.PREUSSMANN,etc;Zeitshrift fur Krebforschung 69，103-201，1967）が指摘されるに及び、健康面からその使用は忌避される傾向にある。
【０００６】
これらの問題を改善したものとして、本出願人らが開発した特開平１０−１１４８９２号と、同１１−３１５３８７号に開示の技術がある。このうち特開平１０−１１４８９２号に開示された技術は、亜硝酸塩、ｐＨ緩衝剤、ベンゾトリアゾールを混合したものであるが、この混合物には、多湿条件下で保存したときに茶色に着色するという問題がある。また特開平１１−３１５３８７号は、ＤＩＣＨＡＮと有機または無機のアンモニウム塩と結晶性セルロース等の保水剤を混合したものであるが、この混合物は低湿度環境下での防錆能に欠ける。
【０００７】
本発明者らは上記のような問題点を改善すべく更に研究を重ねた結果、気化性固形防錆剤として初期防錆能、長期防錆能および長距離有効到達性能のいずれにおいても優れた性能を発揮し、且つ健康障害を生じることなく、更には錆が発生し易い高温多湿条件下においても優れた防錆能を有し、且つ防錆対象製品への付着による汚染を可及的に抑えることのできる気化性固形防錆剤の提供を期して研究を重ね、その一環として特開平１３−３１９６６号に開示の気化性固形防錆剤を開発し、先に提案した。
【０００８】
この気化性固形防錆剤は、有機アミンおよび／または金属の亜硝酸塩と、無機酸および／または有機酸のアンモニウム塩と、炭酸水素金属塩と、保水性または水持続放出性助剤を必須成分として含有せしめたもので、短期・長期のいずれにおいても優れた防錆能を示し、且つ高湿度雰囲気中においても優れた防錆作用を発揮すると共に、錠剤や粉粒状で取扱い性にも優れたもので且つ被防錆対象物に付着して汚染することもないことから、非常に優れたものと評価される。
【０００９】
しかしこの気化性固形防錆剤には、下記の点で改善の余地を残している。即ちこの気化性固形防錆剤は、防錆活性成分の加水分解反応性が非常に高いため、製造時に原料中の水分を極力少なくしなければならないため厳重な製造管理が必要であり、しかも保管時の吸水を阻止するのに酸素バリア性や水蒸気バリア性の高いハイバリア性のフィルム（例えば、アルミ蒸着フィルムやシリカ蒸着フィルムなど）を用いて厳重に包装しておかなければ、防錆活性成分が早期に分解気化して防錆活性を失うことが分った。
【００１０】
【発明が解決しようとする課題】
本発明は上記の様な事情に着目してなされたものであって、その目的は、例えばフィルム厚みが約６０μｍ程度の汎用のポリエチレン製フィルムなどに包装して保管した場合でも、防錆活性成分の気化損失が少なく、製造管理や保存管理を簡素化することができ、併せて、短期・長期のいずれにおいても優れた防錆能を示し、且つ高湿度雰囲気中においても優れた防錆作用を発揮すると共に、保存安定性に優れ、錠剤や粉粒状で取扱い性にも優れ且つ被防錆対象物に付着して汚染することもない、といった特徴を備えた気化性固形防錆剤を提供することにある。
【００１１】
【課題を解決するための手段】
上記課題を解決することのできた本発明の気化性固形防錆剤とは、有機および／または無機の亜硝酸塩と、保水性および／または水持続放出性助剤と、酸物質とを必須成分として含有するところに要旨が存在する。
【００１２】
本発明においては、上記防錆有効成分を錠剤状、粉粒状、顆粒状などに成形し、好ましくは不織布や通気性発泡シート内に封入して商品化すれば、有効成分が使用時もしくは保存時に飛散することがないので便利である。
【００１３】
上記成分のうち、亜硝酸塩として特に好ましいのは、ジシクロヘキシルアミン亜硝酸塩、亜硝酸ナトリウム、亜硝酸カリウム、亜硝酸カルシウムであり、これらは単独で使用し得る他、必要により２種以上を適宜組合せて使用できる。また保水性および／または水持続放出性助剤として好ましいのは、吸水性樹脂、吸湿性粉末、動物性繊維、植物性繊維、再生繊維、合成繊維、活性炭繊維等であり、これらも必要により２種以上を併用できる。
【００１４】
該保水性および／または水持続放出性助剤は、追って詳述する如く適度の保水性を有すると共に乾燥雰囲気中では適度の水を放出する作用を備えたもので、こうした機能を有効に発揮させるには、下記方法によって求められる保水率が０．１〜１００の範囲内であるものが特に好ましい。
【００１５】
（保水率測定法）
試料を１００℃で２４時間乾燥してからその一定量を秤取し、２５℃で相対湿度１００％に保った容器内に入れる。同温度・同湿度で２４時間放置した後に取り出して質量を測定し、下記式によって保水率を求める。
【００１６】
保水率＝（保水後の質量−乾燥状態の質量）×１００／乾燥状態の質量
こうした保水率を備えた保水性および／または水持続放出性助剤のより好ましい例としては、セルロース系の繊維粉末、例えばパルプ粉末などであり、この他、安息香酸ナトリウム、無水硫酸ナトリウム、ポリビニルアルコール、カルボキシメチルセルロース等の粉末も好ましく使用される。
【００１７】
前記酸物質の具体例としては、防錆機能を発揮する前記有効成分を水に溶解したときにｐＨを酸性にする機能を備えた無機酸粉末や無機酸金属塩粉末、有機酸粉末、或いは有機酸をアルカリ金属で部分中和した塩の粉末が挙げられ、無機酸の好ましい具体例としては、硫酸水素ナトリウム、硫酸水素カリウム、リン酸二水素ナトリウム、リン酸二水素カリウム、リン酸二水素カルシウム、ピロリン酸、ホウ酸等が、また有機酸の好ましい具体例としては脂肪族カルボン酸、芳香族カルボン酸およびそれらの酸無水物、オキシカルボン酸、ポリアミノカルボン酸、アスコルビン酸などが、また、有機酸をアルカリ金属で部分中和した塩の粉末の好ましい具体例としては、コハク酸１ナトリウム塩、エチレンジアミン４酢酸の２ナトリウム塩など挙げられる。これらの酸物質も、単独で使用し得る他、必要により２種以上を適宜組合せて使用できる。
【００１８】
本発明において、前記亜硝酸塩と、保水性および／または水持続放出性助剤の好ましい含有比率は、質量比で９９．９：０．１〜１０：９０、より好ましくは９９:１〜２０：８０の範囲であり、また、これら亜硝酸塩と保水性および／または水持続放出性助剤の総和と酸物質との好ましい含有比率は、質量比で８０：２０〜９９．９：０．１、より好ましくは９０：１０〜９９：１の範囲である。
【００１９】
【発明の実施の形態】
上記の様に本発明の気化性固形防錆剤は、有機および／または無機の亜硝酸塩と、保水性および／または水持続放出性助剤（以下、保水性助剤ということがある）と、酸物質とを必須成分として含有するもので、防錆活性成分となる有機および／または無機の亜硝酸塩は多少の水分が共存する場合でも簡単には加水分解を起こさず、酸性水が共存した時に初めて分解気化が加速される。よって本発明では、酸物質が吸水溶解して初めて亜硝酸塩の分解気化が起こるが、酸性水は、ある程度の水分の吸収と該水分への酸物質の溶解によって初めて生成する。換言すると本発明の気化性固形防錆剤では、水分の吸収が律速となって亜硝酸塩の分解気化が起こり、僅かな吸水では分解気化は起こらない。
【００２０】
そのため、製造工程や保管時における水分管理をそれほど厳重にしなくとも、防錆活性成分である亜硝酸塩の分解気化ロスを最小限に抑えることが可能となる。但し開封後は、保水性助剤によって適量の水分が補給されるので、短期・長期のいずれにおいても優れた防錆能を示すし、高湿度雰囲気中においても優れた防錆作用を発揮する。
【００２１】
従って、上記防錆有効成分を錠剤、粉粒状、顆粒状などに成形し、好ましくは不織布や通気性シート内に封入して商品化すれば、保管時における防錆有効成分をロスすることなく、また開封後は短期および長期の何れにおいても優れた防錆機能を発揮する。しかも粉粒状などの防錆有効成分が飛散して被防錆対象物に付着し汚染する恐れもない。
【００２２】
こうした目的に叶う亜硝酸塩としては有機および／または無機の種々の亜硝酸塩が挙げられるが、中でも特に好ましいのは、ジシクロヘキシルアミン亜硝酸塩、亜硝酸ナトリウム、亜硝酸カリウム、亜硝酸カルシウムであり、これらは単独で使用し得る他、必要により２種以上を適宜組合せて使用できる。これらの中でも特に好ましいのはジシクロヘキシルアミン亜硝酸塩である。
【００２３】
また前記酸物質は、後述する吸水性助剤が吸収した水に溶解し、酸性水を生成するものであればよく、水に可溶性の無機酸粉末や無機酸金属塩粉末、或いは有機酸粉末、有機酸をアルカリ金属で部分中和した塩の粉末が挙げられる。無機酸およびその塩の好ましい具体例としては、硫酸水素ナトリウム、硫酸水素カリウム、リン酸二水素ナトリウム、リン酸二水素カリウム、リン酸二水素カルシウム、ピロリン酸、ホウ酸等が挙げられ、また有機酸の好ましい具体例としては、シュウ酸、コハク酸等の脂肪族カルボン酸、安息香酸、フタル酸等の芳香族カルボン酸、無水マレイン酸等の酸無水物、リンゴ酸、クエン酸等のオキシカルボン酸、エチレンジアミン４酢酸等のポリアミノカルボン酸、その他アスコルビン酸などが、また有機酸をアルカリ金属で部分中和した塩の好ましい具体例としては、コハク酸１ナトリウム、エチレンジアミン四酢酸２ナトリウム塩など挙げられる。これらの酸物質も、単独で使用し得る他、必要により２種以上を適宜組合せて使用できる。
【００２４】
また保水性助剤は、前述の如く酸物質の溶解により酸性水を生成して亜硝酸塩の分解気化を進める上で欠くことのできない成分であり、例えば、吸水性樹脂、吸湿性粉末、動物性繊維、植物性繊維、再生繊維、合成繊維、活性炭繊維など、化合物内に水酸基を数多く持った糖類の粉末、カルボキシメチルセルロースのような吸湿増粘性粉末や吸湿性粉末等、適度の保水性を有するものであればよい。これらの中でも、容易に入手できるものとして特に好ましいのは、吸湿性樹脂粉末、羊毛などの動物性繊維、綿や麻などの植物性繊維、ビスコースレーヨンなどの再生繊維、親水性の各種合成繊維、活性炭繊維から選ばれる少なくとも１種である。繊維として特に好ましいのはセルロース繊維粉末である。
【００２５】
該保水性助剤は、追って詳述する如く適度の保水性を有すると共に乾燥雰囲気中では適度の水を放出する作用を備えたもので、こうした機能を有効に発揮させるには、前記方法によって求められる保水率が０．１〜１００の範囲のものであり、特に好ましいのは１〜５０の範囲内のものである。
【００２６】
こうした保水率を備えた保水性助剤のより好ましい例は、セルロース系の繊維粉末、例えばパルプ粉末などであり、この他、安息香酸ナトリウム、無水硫酸ナトリウム、ポリビニルアルコール、カルボキシメチルセルロース等の粉末も好ましく使用される。
【００２７】
これらの保水性助剤は、後述する如く使用時に雰囲気中の水分を適度に吸水して酸物質を溶解させ、酸性水の生成により有機および／または無機の亜硝酸塩の加水分解を促し亜硝酸として気化させる上で重要な機能を果たす。
【００２８】
即ち、発錆が著しい比較的高温多湿雰囲気下では、大気中の水分が保水性助剤に保持され、更にこの水に酸物質と亜硝酸塩が溶解して、水の存在下で例えば下記式で示す様な分解反応を起こし、常温において蒸気圧が高く且つ防錆効果に優れた亜硝酸を生成する。
（Ｃ₆Ｈ₁₁）₂ＮＨ・ＨＮＯ₂＋Ｒ-Ｈ→（Ｃ₆Ｈ₁₁）₂ＮＨ・Ｒ-Ｈ＋ＨＮＯ₂
（式中、Ｒ-Ｈは酸物質を表わす）
【００２９】
また低湿度の環境では加水分解が抑制され、必要以上にジシクロヘキシルアミン亜硝酸塩が分解して気化損失することが無く、長期的に優れた防錆作用を持続する。保水性助剤が保持もしくは放出する水分による加水分解作用によって、初期防錆能、長期防錆能、高温多湿下での防錆能のすべてに優れた作用を発揮するのである。
【００３０】
本発明の気化性固形防錆剤における上記各成分の好ましい含有比率は、前記亜硝酸塩と保水性助剤の比率が、質量比で９９．９：０．１〜１０：９０、亜硝酸塩と保水性助剤の総和と酸物質の比率が、質量比で８０：２０〜９９．９：０．１の範囲である。上記亜硝酸塩、保水性助剤および酸物質の３者の好ましい比率は、９５〜１０／４．９〜８０／０．１〜１０である。保水性助剤が４．９％未満で酸物質が０．１％未満では初期防錆能が不足気味となり、保水性助剤が８０％を超えると、亜硝酸塩量が相対的に少なくなって長期防錆能が不足気味となり、酸物質が１０％を超えると、初期防錆能が強くなり過ぎるため初期の亜硝酸の気化が必要以上に多くなり、長期防錆能が低くなる傾向が表れてくる。
【００３１】
そして、上記好適配合組成の範囲内に設定すれば、使用時の初期防錆能および長期防錆能の何れにも優れた性能の粉末状もしくは粒状の気化性固形防錆剤を得ることができる。
【００３２】
本発明の気化性固形防錆剤を構成する必須成分は上記の３種であるが、必要によっては更に適量のバインダーや増量剤、顔料、色素などを配合してもよく、これらを混合した混合粉末、またはこれを任意の方法で造粒した粒状もしくは顆粒状物や錠剤として使用できる。
【００３３】
但し、実際の商品として実用化する際には、保管や取扱い性を高めるため、上記粉粒体や顆粒、錠剤などを通気性の不織布、あるいは穴明きフィルムや連続気泡タイプの発泡フィルムの如き通気性フィルムからなる袋などに適量（例えば５ｇ程度）包装し、更に該包装体をポリオレフィンフィルムの如き適度のガスバリア性を有するフィルムに密封して保管乃至搬送し、使用時に該フィルムを開封して使用するのがよい。
【００３４】
ここで使用される不織布もしくは通気性フィルムの種類も特に制限されず、要は、粉状や粒状、錠剤などの気化性固形防錆剤の漏出を防止しつつ、水蒸気や気化ガスの通過を許すものであれば、通常の植物性繊維、動物性繊維、再生繊維、合成繊維などの不織布、或いは各種樹脂の連続発泡シート、穴明きフィルムなどがすべて使用可能である。
【００３５】
上記の様に本発明の気化性固形防錆剤は、有機および／または無機の亜硝酸塩と保水性助剤および酸物質の少なくとも３種を有効成分として含み、好ましくはこれを不織布や通気性フィルムなどで包装することにより、後記実施例でも明らかにする如く、酸化腐食性金属材に対して初期および長期の何れにおいても優れた防錆効果を発揮する防錆剤を得ることができる。
【００３６】
しかも本発明の気化性固形防錆剤は、適量の水を吸収した後、これに酸物質が溶解して酸性水となってから初めて分解気化を起こすので、製造時や保管時にそれほど厳密な水分管理をせずとも防錆有効成分の分解ロスを起こすことがなく、製造ないし包装および保管の簡素化を図ることが可能となる。
【００３７】
【実施例】
以下、実施例を挙げて本発明をより具体的に説明するが、本発明はもとより下記実施例によって制限を受けるものではなく、前・後記の趣旨に適合し得る範囲で適当に変更を加えて実施することも勿論可能であり、それらはいずれも本発明の技術的範囲に包含される。
【００３８】
実施例
ジシクロヘキシルアミン亜硝酸塩と保水性助剤および酸物質を、下記表１に示す比率（質量比）で配合し、その０．５ｇを不織布内にシールパックし、２５℃に調節した室内に置いた約１７．５リットル（３３×２３×２３ｃｍ³）のアクリル樹脂製箱内に入れ、同時に２００ｍｌの３５％グリセリン水を箱内に置いて、箱内の相対湿度をＲＨ９０％に設定し、同時に１０ｍ１の３５％グリセリン水を入れた内径４０ｍｍ、高さ４０ｍｍ（液表面積１２．６ｃｍ²）の秤量瓶を３個置いた。
【００３９】
この状態で２４時間静置してから秤量瓶を取り出し、金属表面を不動態化して防錆する亜硝酸イオンの発生量を、気化溶解亜硝酸（ＮＯ₂ ^-）のイオン濃度として測定（初期の亜硝酸量）することにより、比較防錆剤との防錆効果を比較した。また、２５℃、ＲＨ９０％の環境に１ヶ月放置した後、長期の亜硝酸量として同様に気化性亜硝酸量を測定した。
【００４０】
また、ＪＩＳＺ１５１９、４．５で定める暴露後の錆止め性を参考にして、６０℃の恒温槽に５日間保持した後に表１と同じ試験を行って初期の亜硝酸塩量を測定し、下記表２に示す結果を得た。
【００４１】
また、同じアクリル樹脂箱内に、不織布製袋に入れた防錆剤と、ＪＩＳＧ４０５１に規定される機械構造用炭素鋼鋼材「Ｓ２５Ｃ」（３０×３０×１０ｍｍ³）を懸垂し、２００ｍｌの３５％グリセリン水の中に水中ヒーターを設置して２０時間放置し、水中ヒーターに通電して鋼材を３時間結露状態に暴露した後、該鋼材表面の発錆状態を評価した。結果を表３に示す。
○：錆なし、×：錆有り
【００４２】
また、ＪＩＳＺ１５１９、４．４に準拠し、１リットルのガラス瓶での「気化性錆止め試験」（簡便法）を採用し、防錆剤０．０５ｇを使用し、冷水の注加と結露操作を各々１時間（即効性評価）、および２０時間（遅効性評価）で行い、錆の発生の有無を確認した。なお、６０℃の恒温槽に５日間保持した暴露後の防錆剤についても同様に測定した。既知の防錆剤（Ｎｏ．１２，１３）と、本発明の規定要件を満たすＮｏ．３の防錆剤について評価し、下記表４に示す結果を得た。
○：１時間、および２０時間共に錆なし、×：１時間錆あり、２０時間錆なし
【００４３】
また、保存安定性について下記の試験法によって比較した。本発明の規定要件を満たすＮｏ．２の防錆剤と、特開平１３−３１９６６号に開示の気化性防錆剤（ＤＩＣＨＡＮ：５０％、安息香酸アンモニウム：３０％、炭酸水素ナトリウム：３％、セルロース：１％、粉末樹脂：１６％よりなる固形防錆剤）の各々５ｇを、６０μｍのポリエチレン袋（１０ｃｍ角）にシール密封し、２５℃、ＲＨ９０％に調整したアクリル樹脂製箱内に１ヶ月と、５０℃の乾燥機に７日間保存し、ＤＩＣＨＡＮの残量を硫酸第二セリウムによる滴定によって測定し、下記表５に示す結果を得た。
【００４４】
【表１】

【００４５】
【表２】

【００４６】
【表３】

【００４７】
【表４】

【００４８】
【表５】

【００４９】
上記表１において、Ｎｏ．１〜１１は本発明の規定要件を満たす実施例、Ｎｏ．１２は現在市販されている既知の気化性固形防錆剤で、ジシクロヘキシルアミン亜硝酸塩１００％の粉末である。Ｎｏ．１３は現在市販されている既知の気化性固形防錆剤で、ジシクロヘキシルアミン亜硝酸塩８０％とジイソプロピルアミン亜硝酸塩２０％の粉末混合品である。Ｎｏ．１４〜２０は、本発明で定める要件の一部を欠くものである。
【００５０】
これらの結果を対比すれば明らかな様に、本発明の規定要件を満たすＮｏ．１〜１１は、Ｎｏ．１２，１７〜２０に比べていずれも優れた防錆能を有していることが分る。またＮｏ．１２は、初期、長期ともに亜硝酸量が低く、大容量において防錆効果を期待するには３０ｃｍ間隔で防錆剤を吊り下げる必要がある。Ｎｏ．１３は、初期の亜硝酸量が多く防錆試験の結果は良好であるが、発癌性を有することが指摘されているジイソプロピル−Ｎ−ニトロソアミンを生成する可能性のあるジイソプロピルアミン亜硝酸塩を使用しているため、実用性を欠く。
【００５１】
Ｎｏ．１４〜１６は、初期の亜硝酸量が多く防錆試験結果は良好であるが、長期の亜硝酸量が少なくなり、大容量で防錆効果を発揮するには持続性が悪く、防錆剤を数多く吊り下げる必要が生じてくる。酸物質のないＮｏ．１７〜２０は、初期、長期共に亜硝酸量が少なくて防錆能が乏しい。これらに対し本発明の規定要件を満たす実施例Ｎｏ．１〜１１であれば、長期的に大量の防錆ガスが発生するため、防錆剤から２ｍの距離においても優れた防錆効果を示し、防錆処理の工程が簡便となる。
【００５２】
上記表２において、Ｎｏ．１２は暴露後も変化せず、Ｎｏ．１３は変化して共に初期防錆能が悪いが、Ｎｏ．２の実施例では、暴露後においても優れた初期防錆能を維持している。
【００５３】
また表３において、初期防錆力が不足するＮｏ．１２では、１０ｇの防錆剤量で発錆が認められるのに対し、Ｎｏ．２の実施例は、Ｎｏ．１３と同等の優れた初期防錆能を有していることが分る。
【００５４】
上記表４においてＮｏ．３の防錆剤は、公知の即効性防錆剤であるＮｏ．１３と同様に１時間で防錆能を示し、暴露後も優れた防錆即効性を有しているが、Ｎｏ．１３は暴露後の即効性が劣化して遅効性しか示さなくなる。
【００５５】
また上記表５において、６０μｍのポリエチレン袋での保存において、Ｎｏ.２の防錆剤は、２５℃、ＲＨ９０％の環境においても、また５０℃の環境においてもＤＩＣＨＡＮの濃度変化が少なく安定であるが、特開平１３−３１９６６号に開示の気化性固形防錆剤は、何れの環境においても保存安定性が悪い。
【００５６】
【発明の効果】
本発明は以上の様に構成されており、有機および／または無機の亜硝酸塩と保水性助剤および酸物質の少なくとも３種を有効成分として好適比率で配合することにより、比較的簡便な製造条件や包装を採用した場合でも、乾燥雰囲気および多湿雰囲気下、或いは短期・長期の何れにおいても優れた防錆性能を示す気化性固形防錆剤を提供し得ることになった。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vaporizable solid rust preventive agent, for example, when storing, transporting, or transporting equipment or parts made of metals that are susceptible to oxidation, such as various mechanical parts made of steel and automobile parts. Is a vaporizable solid rust preventive agent to prevent rusting due to oxidation, especially in the short term and long term, and at the same time adheres to the surface of rust protected parts It relates to a vaporizable solid rust preventive agent that does not cause contamination due to slag.
[0002]
[Prior art]
Conventionally, as a rust prevention measure for metal members such as those mentioned above, an oil film is formed by applying an antirust oil to the surface of the metal member that is subject to rust prevention, and oxygen and moisture that cause rusting. It is a method to block. However, in the method using rust-preventive oil, removal of the oil film after use is complicated, so recently it has demonstrated excellent rust-prevention effect with a small amount, and vaporization that can be easily removed after use The solid rust preventive agent has begun to be put into practical use.
[0003]
This type of vaporizable solid rust preventive is generally called VCI (Volatile Corrosion Inhibitor), and a typical example is a sublimable cyclohexylamine carbonate [(C ₆ H ₁₁ NH) ₂ HCO _2. : CHC] and diisopropylamine nitrite {[(CH ₃ ) ₂ CH] ₂ NH · HNO ₂ : DIPAN}, dicyclohexylamine nitrite [(C ₆ H ₁₁ ) ₂ NH · HNO ₂ : DICHAN], etc. Yes.
[0004]
However, although CHC exhibits excellent initial rust prevention ability, it has a strong odor, and its vapor pressure is as high as 4 × 10 ^-1 mmHg (25 ° C). Must be done. On the other hand, although DICHAN is excellent in long-term rust prevention ability, the vapor pressure is as low as 1 × 10 ⁻⁴ mmHg (25 ° C.), and it takes 20 hours or more to exert the rust prevention effect. Lack. Moreover, when the distance from the rust prevention target article is 20 to 30 cm or more, a sufficient rust prevention effect is not exhibited.
[0005]
Moreover, the vapor pressure of DIPAN is 5 × 10 ⁻³ mmHg (25 ° C.), which is intermediate between CHC and DICHAN, and has both excellent initial rust prevention ability and long-term rust prevention ability. , Part of which is known to be altered to produce diisopropyl-N-nitrosamine, which is carcinogenic (H. DRUCKRW, R. PREUSSMANN, etc; Zeitshrift fur Krebforschung 69, 103-201, 1967), and its use tends to be avoided for health reasons.
[0006]
As a solution to these problems, there are techniques disclosed in Japanese Patent Application Laid-Open Nos. 10-114892 and 11-315387 developed by the present applicants. Among them, the technique disclosed in Japanese Patent Application Laid-Open No. 10-114892 is a mixture of nitrite, pH buffer, and benzotriazole, but this mixture is colored brown when stored under humid conditions. There's a problem. JP-A-11-315387 discloses a mixture of DICHAN, an organic or inorganic ammonium salt, and a water retention agent such as crystalline cellulose, but this mixture lacks rust prevention ability in a low humidity environment.
[0007]
As a result of further studies to improve the above problems, the present inventors were excellent in any of initial rust prevention ability, long-term rust prevention ability and long-range effective reach performance as a vaporizable solid rust inhibitor. It has excellent rust prevention ability under high-temperature and high-humidity conditions where it exhibits performance and does not cause health problems, and rust is likely to occur. As a part of such research, the vaporizable solid rust inhibitor disclosed in JP-A No. 13-31966 was developed and proposed previously.
[0008]
This vaporizable solid rust inhibitor is composed of organic amine and / or metal nitrite, inorganic acid and / or organic acid ammonium salt, hydrogen carbonate metal salt, and water retention or water sustained release aid as essential components. In addition to exhibiting excellent anti-rust performance in both short-term and long-term, it also exhibits excellent anti-rust performance in high-humidity atmospheres, and is also excellent in handleability with tablets and powders Since it is a thing and does not adhere to a to-be-rusted target object and it is contaminated, it is evaluated as being very excellent.
[0009]
However, this vaporizable solid rust inhibitor still has room for improvement in the following points. In other words, this vaporizable solid rust preventive agent has a very high hydrolysis reactivity of the rust preventive active ingredient. Therefore, it is necessary to reduce the moisture in the raw material as much as possible at the time of manufacture. In order to prevent water absorption at the time, unless it is strictly packaged with a high-barrier film (for example, an aluminum vapor-deposited film or a silica vapor-deposited film) having a high oxygen barrier property or water vapor barrier property, It was found that it decomposes and vaporizes early and loses rust prevention activity.
[0010]
[Problems to be solved by the invention]
The present invention has been made paying attention to the above-mentioned circumstances, and the purpose thereof is, for example, a rust preventive active ingredient even when packaged and stored in a general-purpose polyethylene film having a film thickness of about 60 μm. Evaporation loss is low, manufacturing management and storage management can be simplified, and at the same time, it exhibits excellent rust prevention performance in both short and long term, and also has excellent rust prevention action in a high humidity atmosphere. Provided is a vaporizable solid rust preventive agent which has characteristics such as excellent storage stability, tablet and granular form, excellent handleability, and does not adhere to and contaminate an object to be rusted. There is.
[0011]
[Means for Solving the Problems]
The vaporizable solid rust preventive agent of the present invention that has solved the above-mentioned problems includes organic and / or inorganic nitrites, water retention and / or water sustained release aids, and acid substances as essential components. There is a gist where it is contained.
[0012]
In the present invention, the active ingredient is formed into a tablet, powder, granule, etc., preferably enclosed in a non-woven fabric or a breathable foam sheet and commercialized. It is convenient because it does not scatter.
[0013]
Of the above components, dicyclohexylamine nitrite, sodium nitrite, potassium nitrite, and calcium nitrite are particularly preferred as nitrites, and these can be used alone or in combination of two or more as necessary. it can. Further, water-absorbing resins, hygroscopic powders, animal fibers, plant fibers, regenerated fibers, synthetic fibers, activated carbon fibers, etc. are preferable as water retention and / or water sustained release aids. More than one species can be used in combination.
[0014]
The water retention and / or water sustained release auxiliary agent has an appropriate water retention property as described in detail later and has an action of releasing an appropriate amount of water in a dry atmosphere, and effectively exerts such a function. Particularly preferred are those having a water retention rate in the range of 0.1 to 100 determined by the following method.
[0015]
(Water retention measurement method)
The sample is dried at 100 ° C. for 24 hours, and a certain amount thereof is weighed and placed in a container kept at 25 ° C. and 100% relative humidity. After leaving it to stand at the same temperature and humidity for 24 hours, it is taken out and weighed, and the water retention rate is obtained by the following formula.
[0016]
Water retention rate = (mass after water retention−mass in dry state) × 100 / mass in dry state As a more preferred example of the water retention and / or water sustained release auxiliary agent having such a water retention rate, cellulosic fiber powder For example, pulp powder and the like, and powders such as sodium benzoate, anhydrous sodium sulfate, polyvinyl alcohol, and carboxymethyl cellulose are also preferably used.
[0017]
Specific examples of the acid substance include an inorganic acid powder, an inorganic acid metal salt powder, an organic acid powder, or an organic acid powder having a function of making the pH acidic when the active ingredient exhibiting a rust prevention function is dissolved in water. Specific examples of inorganic acids include sodium hydrogen sulfate, potassium hydrogen sulfate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, and calcium dihydrogen phosphate. , Pyrophosphoric acid, boric acid and the like, and preferable specific examples of the organic acid include aliphatic carboxylic acid, aromatic carboxylic acid and acid anhydrides thereof, oxycarboxylic acid, polyaminocarboxylic acid, ascorbic acid and the like. Preferable specific examples of the salt powder obtained by partially neutralizing the acid with an alkali metal include succinic acid monosodium salt, ethylenediaminetetraacetic acid disodium salt, and the like. It is below. These acid substances can be used alone or in combination of two or more as necessary.
[0018]
In the present invention, the preferred content ratio of the nitrite and the water retention and / or water sustained release aid is 99.9: 0.1 to 10:90, more preferably 99: 1 to 20: by mass ratio. The preferred content ratio of the nitrite, the water retentive and / or water sustained release aid, and the acid substance is 80:20 to 99.9: 0.1 by mass ratio. More preferably, it is in the range of 90:10 to 99: 1.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
As described above, the vaporizable solid rust inhibitor of the present invention comprises an organic and / or inorganic nitrite, a water retention and / or water sustained release aid (hereinafter sometimes referred to as a water retention aid), It contains an acid substance as an essential component, and the organic and / or inorganic nitrite that is the rust-preventing active ingredient does not easily hydrolyze even when some moisture coexists, and when acidic water coexists Decomposition and vaporization is accelerated for the first time. Therefore, in the present invention, decomposition and vaporization of nitrite occurs only after the acid substance absorbs and dissolves in water, but acidic water is generated for the first time by absorbing a certain amount of water and dissolving the acid substance in the water. In other words, in the vaporizable solid rust preventive agent of the present invention, moisture absorption is rate-determined to cause decomposition and vaporization of nitrite, and slight water absorption does not cause decomposition and vaporization.
[0020]
Therefore, it is possible to minimize the loss of decomposition and vaporization of nitrite, which is an antirust active component, even if the water management during the manufacturing process and storage is not so strict. However, after opening, an appropriate amount of water is replenished by the water retention aid, so that it exhibits excellent antirust performance both in the short term and in the long term, and exhibits an excellent antirust effect even in a high humidity atmosphere.
[0021]
Therefore, if the above rust preventive active ingredient is molded into tablets, powder granules, granules, etc., preferably encapsulated in a nonwoven fabric or a breathable sheet and commercialized, without loss of the rust preventive active ingredient during storage, In addition, after opening, it exhibits an excellent antirust function both in the short and long term. Moreover, there is no possibility that the rust preventive active ingredients such as powder particles are scattered and adhere to the object to be rusted and contaminated.
[0022]
Nitrites for such purposes include various organic and / or inorganic nitrites, and among them, dicyclohexylamine nitrite, sodium nitrite, potassium nitrite, and calcium nitrite are particularly preferable. In addition, two or more kinds can be used in appropriate combination as necessary. Of these, dicyclohexylamine nitrite is particularly preferred.
[0023]
Further, the acid substance may be any one that dissolves in water absorbed by the water-absorbing auxiliary agent described later and generates acidic water, such as an inorganic acid powder or inorganic acid metal salt powder soluble in water, or an organic acid powder, Examples thereof include a salt powder obtained by partially neutralizing an organic acid with an alkali metal. Specific examples of preferred inorganic acids and salts thereof include sodium hydrogen sulfate, potassium hydrogen sulfate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, calcium dihydrogen phosphate, pyrophosphoric acid, boric acid, and the like. Preferred examples of the acid include aliphatic carboxylic acids such as oxalic acid and succinic acid, aromatic carboxylic acids such as benzoic acid and phthalic acid, acid anhydrides such as maleic anhydride, and oxycarboxylic acids such as malic acid and citric acid. Preferred specific examples of acids, polyaminocarboxylic acids such as ethylenediaminetetraacetic acid, other ascorbic acids, etc., and organic acids partially neutralized with alkali metals include monosodium succinate and disodium ethylenediaminetetraacetic acid. . These acid substances can be used alone or in combination of two or more as necessary.
[0024]
Further, as described above, the water retention aid is a component that is indispensable for generating acidic water by dissolving an acid substance and promoting decomposition and vaporization of nitrite. For example, a water absorbing resin, a hygroscopic powder, an animal Fibers, plant fibers, regenerated fibers, synthetic fibers, activated carbon fibers, etc. that have moderate water retention, such as sugar powders with many hydroxyl groups in the compound, hygroscopic thickening powders and hygroscopic powders such as carboxymethylcellulose If it is. Among these, hygroscopic resin powder, animal fibers such as wool, vegetable fibers such as cotton and hemp, regenerated fibers such as viscose rayon, and various synthetic fibers having hydrophilic properties are particularly preferable as easily available materials. , At least one selected from activated carbon fibers. Particularly preferred as the fiber is cellulose fiber powder.
[0025]
The water retention aid has an appropriate water retention property as described in detail later and has an action of releasing an appropriate amount of water in a dry atmosphere. The water retention rate is in the range of 0.1 to 100, particularly preferably in the range of 1 to 50.
[0026]
More preferable examples of the water retention aid having such a water retention rate are cellulose fiber powders such as pulp powder, and other powders such as sodium benzoate, anhydrous sodium sulfate, polyvinyl alcohol, and carboxymethyl cellulose are also preferable. used.
[0027]
As described later, these water retention aids absorb water in the atmosphere appropriately at the time of use to dissolve the acid substance, and promote the hydrolysis of organic and / or inorganic nitrite by the formation of acidic water to form nitrous acid. It plays an important function in vaporizing.
[0028]
That is, in a relatively high temperature and high humidity atmosphere where rusting is remarkable, moisture in the atmosphere is retained by the water retention aid, and further, an acid substance and nitrite are dissolved in this water. The decomposition reaction shown in the figure occurs, and nitrous acid having a high vapor pressure at room temperature and excellent antirust effect is produced.
(C ₆ H ₁₁ ) ₂ NH.HNO ₂ + R—H → (C ₆ H ₁₁ ) ₂ NH.R—H + HNO ₂
(Where R—H represents an acid substance)
[0029]
In addition, hydrolysis is suppressed in a low humidity environment, dicyclohexylamine nitrite is not decomposed more than necessary and vaporization loss is maintained, and an excellent rust prevention effect is maintained over a long period of time. Due to the hydrolysis action by the water retained or released by the water retention aid, the initial rust prevention ability, the long-term rust prevention ability, and the rust prevention ability under high temperature and high humidity are exhibited.
[0030]
The preferred content ratio of the above components in the vaporizable solid rust preventive agent of the present invention is such that the ratio of the nitrite to the water retention aid is 99.9: 0.1 to 10:90 in mass ratio, nitrite and water retention. The ratio of the total of the auxiliary assistants and the acid substance is in the range of 80:20 to 99.9: 0.1 by mass ratio. A preferable ratio of the above-mentioned nitrite, water retention aid and acid substance is 95 to 10 / 4.9 to 80 / 0.1 to 10. If the water retention aid is less than 4.9% and the acid substance is less than 0.1%, the initial rust prevention ability tends to be insufficient. If the water retention aid exceeds 80%, the amount of nitrite is relatively reduced. Long-term rust prevention ability seems to be insufficient, and if the acid substance exceeds 10%, the initial rust prevention ability becomes too strong, and the initial vaporization of nitrous acid is more than necessary, and there is a tendency for long-term rust prevention ability to be lowered. Come.
[0031]
And if it is set within the range of the above preferred composition, it is possible to obtain a powdery or granular vaporizable solid rust preventive having excellent performance in both initial rust prevention ability and long-term rust prevention ability during use. .
[0032]
The essential components constituting the vaporizable solid rust preventive agent of the present invention are the above-mentioned three kinds, but if necessary, an appropriate amount of binder, extender, pigment, dye, etc. may be blended, and these are mixed. It can be used as a powder, or a granular or granulated product or tablet obtained by granulating the powder by any method.
[0033]
However, when it is put into practical use as an actual product, in order to improve storage and handling, the above granular material, granule, tablet, etc. should be made of breathable nonwoven fabric, perforated film, open cell type foam film, etc. Pack an appropriate amount (for example, about 5 g) in a bag made of a breathable film, and then seal or store the package in a film having an appropriate gas barrier property such as a polyolefin film. It is good to use.
[0034]
The type of non-woven fabric or breathable film used here is not particularly limited. In short, it allows passage of water vapor or vapor while preventing leakage of vaporizable solid rust preventives such as powder, granules and tablets. As long as it is normal, non-woven fabrics such as normal plant fibers, animal fibers, regenerated fibers, and synthetic fibers, continuous foam sheets of various resins, perforated films, and the like can be used.
[0035]
As described above, the vaporizable solid rust preventive agent of the present invention contains at least three kinds of organic and / or inorganic nitrites, water retention aids and acid substances as active ingredients, and preferably these are nonwoven fabrics or breathable films. As will be clarified in the examples described later, it is possible to obtain a rust inhibitor that exhibits an excellent rust preventive effect both in the initial stage and in the long term with respect to the oxidatively corrosive metal material.
[0036]
In addition, the vaporizable solid rust preventive agent of the present invention absorbs an appropriate amount of water, and then decomposes and vaporizes only after the acid substance dissolves and becomes acidic water. Without management, there is no loss of decomposition of the rust-preventive active ingredient, and manufacturing, packaging and storage can be simplified.
[0037]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.
[0038]
Example Dicyclohexylamine nitrite, water retention aid and acid substance were blended at the ratio (mass ratio) shown in Table 1 below, 0.5 g of which was sealed in a nonwoven fabric and placed in a room adjusted to 25 ° C. In an approximately 17.5 liter (33 × 23 × 23 cm ³ ) acrylic resin box, 200 ml of 35% glycerin water is placed in the box at the same time, and the relative humidity in the box is set to RH 90%. Three weighing bottles with an inner diameter of 40 mm and a height of 40 mm (liquid surface area of 12.6 cm ² ) containing 10 ml of 35% glycerin water were placed.
[0039]
After standing for 24 hours in this state, the weighing bottle is taken out, and the amount of nitrite ions that passivate the metal surface to prevent rust is measured as the ion concentration of vaporized dissolved nitrous acid (NO ₂ ⁻ ) The amount of nitrous acid) was compared with that of a comparative rust inhibitor. Further, after being left for 1 month in an environment of 25 ° C. and RH 90%, the amount of vaporizable nitrous acid was similarly measured as the amount of nitrous acid for a long time.
[0040]
In addition, referring to the rust-preventing properties after exposure as defined in JIS Z1519, 4.5, after holding in a thermostatic bath at 60 ° C. for 5 days, the same test as in Table 1 was performed to measure the initial nitrite amount, and the following table The result shown in 2 was obtained.
[0041]
In addition, a rust inhibitor placed in a non-woven bag and a carbon steel material for mechanical structure “S25C” (30 × 30 × 10 mm ³ ) defined in JIS G4051 are suspended in the same acrylic resin box, and 200 ml of 35 ml is suspended. An underwater heater was installed in% glycerin water and left for 20 hours. The underwater heater was energized to expose the steel material to the dew condensation state for 3 hours, and then the rusting state of the steel material surface was evaluated. The results are shown in Table 3.
○: No rust, ×: Rust [0042]
In addition, in accordance with JIS Z1519, 4.4, the “vaporizable rust prevention test” (simple method) in a 1 liter glass bottle is adopted, 0.05 g of rust preventive agent is used, and cold water is added and dew condensation is performed. Each time was 1 hour (immediate effect evaluation) and 20 hours (delayed effect evaluation), and the presence or absence of rust was confirmed. In addition, it measured similarly about the rust preventive after the exposure hold | maintained for 5 days in the 60 degreeC thermostat. Known rust preventives (No. 12, 13) and No. 1 satisfying the requirements of the present invention. 3 was evaluated, and the results shown in Table 4 below were obtained.
○: No rust for both 1 hour and 20 hours, ×: 1 hour rust, 20 hours rust
In addition, the storage stability was compared by the following test method. No. satisfying the prescribed requirements of the present invention. 2 and a vaporizable rust inhibitor disclosed in JP-A No. 13-31966 (DICHAN: 50%, ammonium benzoate: 30%, sodium bicarbonate: 3%, cellulose: 1%, powder resin: 16 5 g of each solid rust preventive agent) in a 60 μm polyethylene bag (10 cm square) sealed and sealed in an acrylic resin box adjusted to 25 ° C. and RH 90% for one month and a dryer at 50 ° C. After storing for 7 days, the remaining amount of DICHAN was measured by titration with ceric sulfate, and the results shown in Table 5 below were obtained.
[0044]
[Table 1]

[0045]
[Table 2]

[0046]
[Table 3]

[0047]
[Table 4]

[0048]
[Table 5]

[0049]
In Table 1 above, no. Nos. 1 to 11 are examples satisfying the requirements of the present invention, No. 1 to No. 11. 12 is a known vaporizable solid rust preventive agent currently on the market and is a powder of 100% dicyclohexylamine nitrite. No. 13 is a known vaporizable solid rust preventive agent currently on the market, which is a powder mixture of 80% dicyclohexylamine nitrite and 20% diisopropylamine nitrite. No. 14 to 20 lack some of the requirements defined in the present invention.
[0050]
As is clear from comparison of these results, No. 1 satisfying the prescribed requirements of the present invention. 1-11 are No.1. It turns out that all have the antirust ability outstanding compared with 12, 17-20. No. No. 12 has a low amount of nitrous acid in both the initial stage and the long term, and it is necessary to suspend the rust inhibitor at intervals of 30 cm in order to expect a rust preventive effect in a large capacity. No. No. 13 uses diisopropylamine nitrite, which has the potential to produce diisopropyl-N-nitrosamine, which has been pointed out to have carcinogenicity, although the amount of nitrous acid is large and the result of the rust prevention test is good. Because it lacks practicality.
[0051]
No. Nos. 14 to 16 have a large amount of nitrous acid at the initial stage and a good rust prevention test result, but the amount of nitrous acid in the long term is small and the sustainability is poor to exhibit the rust prevention effect at a large capacity. It will be necessary to suspend a large number. No. No acid substance. Nos. 17 to 20 have a small amount of nitrous acid in both the initial stage and the long term and have poor rust prevention ability. On the other hand, Example No. If it is 1-11, since a large amount of anticorrosive gas will generate | occur | produce in the long term, the antirust effect which was excellent in the distance of 2 m from an antirust agent is shown, and the process of an antirust process becomes simple.
[0052]
In Table 2 above, no. No. 12 remained unchanged after exposure. No. 13 changed and the initial rust prevention ability was poor. In Example 2, excellent initial rust prevention ability is maintained even after exposure.
[0053]
Further, in Table 3, No. with insufficient initial rust prevention ability In No. 12, rusting was observed with an amount of 10 g of rust inhibitor, whereas The embodiment of No. 2 It can be seen that it has an excellent initial rust preventive ability equivalent to 13.
[0054]
In Table 4 above, no. No. 3 is a known quick-acting rust inhibitor, No. 3. No. 13 shows rust prevention ability in 1 hour as in the case of No. 13, and has excellent anti-rust effect immediately after exposure. In No. 13, the immediate effect after exposure deteriorates and only slow effect is exhibited.
[0055]
In Table 5 above, when stored in a 60 μm polyethylene bag, the No. 2 rust preventive agent is stable with little change in the concentration of DICHAN even in an environment of 25 ° C. and RH 90% and in an environment of 50 ° C. However, the vaporizable solid rust inhibitor disclosed in JP-A No. 13-31966 has poor storage stability in any environment.
[0056]
【The invention's effect】
The present invention is configured as described above, and by mixing at least three kinds of organic and / or inorganic nitrite, water retention aid and acid substance as active ingredients in a suitable ratio, relatively simple production conditions Even in the case of adopting or packaging, it is possible to provide a vaporizable solid rust inhibitor exhibiting excellent rust prevention performance in a dry atmosphere and a humid atmosphere, or in both short and long term.

Claims

Contains organic and / or inorganic nitrite, water retention and / or water sustained release aid, and acid substance as active ingredients ,
The acid substance comprises an inorganic acid powder, an inorganic acid metal salt powder, an organic acid powder, and a salt powder obtained by partially neutralizing an organic acid with an alkali metal when the active ingredient is dissolved in water. At least one selected from
The inorganic acid powder or inorganic acid metal salt powder is selected from the group consisting of sodium hydrogen sulfate, potassium hydrogen sulfate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, calcium dihydrogen phosphate, pyrophosphoric acid, boric acid. A vaporizable solid rust preventive agent characterized by being at least one .

Contains organic and / or inorganic nitrite, water retention and / or water sustained release aid, and acid substance as active ingredients ,
The acid substance comprises an inorganic acid powder, an inorganic acid metal salt powder, an organic acid powder, and a salt powder obtained by partially neutralizing an organic acid with an alkali metal when the active ingredient is dissolved in water. At least one selected from
The organic acid is selected from the group consisting of aliphatic carboxylic acids, aromatic carboxylic acids and their anhydrides, oxycarboxylic acids, polyaminocarboxylic acids, ascorbic acids, and salts obtained by partially neutralizing these acids with alkali metals. A vaporizable solid rust preventive agent characterized by being at least one kind .

The vaporizable solid rust preventive agent according to claim 1 or 2 , which is in tablet form, powder form or granular form.

The vaporizable solid rust inhibitor according to any one of claims 1 to 3, wherein the nitrite is at least one selected from the group consisting of dicyclohexylamine nitrite, sodium nitrite, potassium nitrite, and calcium nitrite.

The water retention and / or water sustained release aid is at least one selected from the group consisting of water absorbent resins, hygroscopic powders, animal fibers, vegetable fibers, regenerated fibers, synthetic fibers, and activated carbon fibers. The vaporizable solid rust preventive agent according to any one of claims 1 to 4 .

Volatile solids anticorrosive agent according to any one of claims 1 to 5, wherein the water retention and / or water-sustained release aids, water retention rate obtained by the following method is 0.1 to 100.
(Method for measuring water retention rate) A sample is dried at 100 ° C. for 24 hours, and a certain amount thereof is weighed and placed in a container kept at 25 ° C. and 100% relative humidity. After leaving it to stand at the same temperature and humidity for 24 hours, it is taken out and weighed, and the water retention rate is obtained by the following formula.
Water retention rate = (mass after water retention−mass in dry state) × 100 / mass in dry state

The vaporizable solid rust inhibitor according to claim 5 or 6 , wherein the water retention and / or water sustained release aid is a cellulosic fiber powder.

The vaporizable solid according to claim 5 or 6 , wherein the water retention and / or water sustained release aid is at least one selected from the group consisting of sodium benzoate, anhydrous sodium sulfate, polyvinyl alcohol, and carboxymethylcellulose. anti-rust.

The content ratio of the nitrite to the water retention and / or water sustained release auxiliary agent is 99.9: 0.1 to 10:90 by mass ratio, and these nitrite, water retention and / or water The vaporizable solid rust preventive agent according to any one of claims 1 to 8 , wherein the content ratio of the sum of the sustained release auxiliary agents and the acid substance is 80:20 to 99.9: 0.1 in terms of mass ratio.

A vaporizable solid rust preventive agent, wherein the active ingredient according to any one of claims 1 to 9 is packaged in a nonwoven fabric or a breathable foam sheet.