JP2004002869A - Clothes washing method and detergent composition for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a clothes washing method using a detergent which exhibits detergency equal to or more than a synthetic detergent containing a surfactant as the main detergent, which is excellent in the property of preventing soil redeposition, and in which the main detergency is obtained from inorganic salts, as well as to provide a detergent composition therefor. <P>SOLUTION: The detergent composition is the one in which the main detergency is obtained from alkaline inorganic salts, and the washing is done using the detergent composition containing at least a soil redeposition preventing agent. <P>COPYRIGHT: (C)2004,JPO

Description

表１によると、アルカリ塩単独の場合、ｐＨ１０以下の領域では十分な濃度とならないため、ｐＨ８．３程度の炭酸水素ナトリウム水溶液と同程度の洗浄力となっている。一方、アルカリ塩単独系ではなく重曹を混合した系の場合、ｐＨが９以上の領域では比較的低いｐＨでも濃度を高くすることにより、ｐＨが高い場合と同程度の洗浄力を得ることができることがわかる。
【００１３】
したがって、重曹のようなｐＨ緩衝作用塩を共存させると緩衝系を形成し、アルカリ作用塩の濃度増加に伴うアルカリ化の促進を抑制しつつ、アルカリ剤の濃度を十分に高めることができる。
【００１４】
炭酸塩や重炭酸塩の水溶液では−２価の炭酸イオンと−１価の重炭酸イオンの存在比率は水溶液のｐＨに依存し、ｐＨ１０．３のときその存在比率はほぼ１：１である。高ｐＨ領域では炭酸イオンが多くなり、低ｐＨ領域では重炭酸イオンがさらに炭酸ガスに変わってゆく。また重炭酸イオンの存在比率が高いほど緩衝作用が強くなり、濃度を変えてもｐＨはほとんど変化しない。したがって、炭酸塩（炭酸イオン）と重炭酸塩（重炭酸イオン）を混合することにより任意の弱アルカリ性域のｐＨを得ることができ、アルカリ剤濃度を高め、かつアルカリ剤濃度によるｐＨ変化の少ない洗浄液とすることができる（表２参照）。
【００１５】
【表２】

さらに、洗浄液中に例えば酸性を呈する汚れが混入したとしても、ｐＨ緩衝作用塩が洗浄液の酸性化の促進を抑制するように作用する結果、洗浄液を洗濯に適した弱アルカリ性範囲に収束維持することができるといった効果を期することもできる。
【００１６】
本発明におけるｐＨ緩衝作用塩とは、たとえば、重炭酸アルカリ金属塩、ほう酸アルカリ金属塩、りん酸アルカリ金属塩などを挙げることができ、しゅう酸アルカリ金属塩、フタル酸アルカリ金属塩のような有機酸塩も補助的に使用できる。また、本発明におけるアルカリ作用塩とは、たとえば、炭酸アルカリ金属塩、ケイ酸アルカリ金属塩などを挙げることができる。
【００１７】
本発明において、前記無機塩は、重炭酸アルカリ金属塩と、炭酸アルカリ金属塩及び／又はケイ酸アルカリ金属塩とを主成分として含有することが好ましい。上述したように、重炭酸アルカリ金属塩の主たる役割はｐＨ緩衝作用であり、炭酸アルカリ金属塩及びケイ酸アルカリ金属塩の主たる役割は洗浄液が呈する液性のアルカリ化促進である。
【００１８】
なお、本発明のアルカリ性無機塩の組成は、基本的には、そのｐＨ緩衝作用を利用するために重炭酸アルカリ金属塩を含むが、炭酸アルカリ金属塩の単独使用でｐＨ１１程度にしたものは、本発明に必要な洗浄力を有しかつ多少の緩衝作用を有する系となるので、本発明のアルカリ性無機塩組成の範疇に含まれる。
【００１９】
また、炭酸アルカリ金属塩は、後述するように良好な軟水化促進作用をも有し、一方、ケイ酸アルカリ金属塩は再汚染防止能力の向上や洗濯機の金属表面の防錆作用を有するとともに、排水系への硬度成分の固着防止作用をも有する。
【００２０】
ケイ酸アルカリ金属塩、とくにメタケイ酸ナトリウムは、洗浄液中においてコロイドを生じ、無機汚れ粒子の吸着乃至洗浄液中への分散作用を有しているために、繊維への汚れ粒子の吸着、つまり再汚染を防止する。また、ケイ酸アルカリ金属塩、とくにメタケイ酸ナトリウム（５水和物）は、本発明の洗浄剤組成物においては、洗浄力を損なうことなく任意の割合で炭酸ナトリウムと置き換えることが可能である。
【００２１】
なお、十分な再汚染防止性能を付与するためには、洗浄液中に０．００１モル／リットル以上となるようにケイ酸アルカリ金属塩の濃度を設定することが望ましい。
【００２２】
本発明において、前記無機塩の総量の洗浄剤組成物総量における配合比率は９０重量％以上であることが好ましい。そして、再汚染防止能力が既存の洗濯石鹸や合成洗剤と同等程度の水準に達するよう後述の再汚染防止物質を存在させることを条件に、当該無機塩配合比率は、９１重量％以上であることがさらに好ましく、以下同様に、同９２重量％以上、同９３重量％以上、同９４重量％以上、同９５重量％以上、同９６重量％以上、同９７重量％以上、同９８重量％以上、同９９重量％以上の順序で、洗浄剤組成物中における無機塩の配合量が多いほど望ましい。主剤による洗浄力向上の効果が得られるからである。
【００２３】
本発明において、前記重炭酸アルカリ金属塩の含有モル数と、前記炭酸アルカリ金属塩の含有モル数との構成比は、１：７乃至１：０．２であることがより好ましい。本発明では、洗浄液の液性が強アルカリに傾くこと起因した繊維の損傷、皮膚障害や排水処理の必要性などの諸弊害を未然に回避するために、ｐＨ緩衝作用塩たる重炭酸アルカリ金属塩を必須の成分として含有することで、洗濯時の洗浄液（例えば１ｇ／Ｌ（０．１重量％）濃度）のｐＨを弱アルカリ性範囲である９〜１１に収束させているが、こうしたｐＨ緩衝系を形成し得る、重炭酸アルカリ金属塩の含有モル数と、炭酸アルカリ金属塩の含有モル数との構成比が、１：７乃至１：０．２に相当する。
【００２４】
重炭酸アルカリ金属塩とケイ酸アルカリ金属塩の組み合わせの場合は、同様に１：１．２乃至１：０．１の含有モル数構成比が好ましい。
【００２５】
さらに、前記主たる洗浄作用成分としてのアルカリ性緩衝系を形成する無機塩として、重炭酸アルカリ金属塩、炭酸アルカリ金属塩、及びケイ酸アルカリ金属塩の三種を混合して用いる場合には、ケイ酸アルカリ金属塩、例えばメタケイ酸ナトリウムが発揮する再汚染防止性能などを考慮して、洗浄剤総重量の２０〜９０重量％、好ましくは３０〜７０重量％の構成比となるようにケイ酸アルカリ金属塩の配合量を設定するのが好ましい。
【００２６】
上記の無機塩の総量や、重炭酸アルカリ金属塩と、炭酸アルカリ金属塩及び／又はケイ酸アルカリ金属塩との配合比率は、当該洗浄剤組成物が対象とする洗濯物の種類、販売対象とする地域の水の硬度や、洗濯温度、洗濯機の形式等の洗濯条件等に応じて、適宜の比率を選択することができる。たとえば、傷み易い衣料の洗濯にはできるだけアルカリ度の低い、すなわち重炭酸アルカリ金属塩の比率の高い配合とすべきであり、硬度の高い地域向けの洗浄剤組成物においては、軟水化作用を重視して炭酸アルカリ金属塩を高い比率で多量配合するのが好ましい。
【００２７】
上記無機塩の組み合わせにおいて重炭酸アルカリ金属塩と炭酸アルカリ金属塩としてナトリウム塩を使用する場合は、それらの物質の等モル混合物であるセスキ炭酸ナトリウムを上記構成比の範囲で置き換えることができる。
１−２）洗浄液のｐＨと無機塩濃度：
洗浄液のｐＨは、主剤混合物中における重炭酸アルカリ金属塩、たとえば重炭酸ナトリウムの配合比率で調整できる。最も単純な構成である炭酸ナトリウムと重炭酸ナトリウムの混合物を水道水で溶解した洗浄液でｐＨと洗浄力の関係を調べてみた。その結果を表３に示す。
【００２８】
【表３】

表３より、ｐＨ９．３程度までは水道水のみと比べ有意差は見られないが、ｐＨ９．５を超えるあたりから洗浄率の有意な上昇が見られる。より高ｐＨ側は弱アルカリ性の範囲で洗浄率はまだ上昇傾向にあるが、好適なｐＨの上限は添加される酵素などとの相性を見て決められる。
【００２９】
したがって、洗浄力の観点からは、本発明の洗浄剤組成物を標準使用濃度、たとえば１ｇ／Ｌ（０．１重量％濃度）に水で溶解したときの洗浄液のｐＨは９．５以上が好ましい。
【００３０】
次に、表４および図１は本発明洗浄液中の無機塩濃度と洗浄力の関係を示す。
【００３１】
【表４】

無機塩濃度が高いほど洗浄率が上昇する傾向にはあるが、あるところからはほとんど上昇が見られなくなる。また本洗浄剤の特徴として洗浄率の上昇変化がほぼ平坦になる「棚」が２つ存在している。一つ目の棚と２つ目の棚の洗浄率には比較的大きな差があり、濃度の高いほうが洗浄率は高くなっている。しかし、濃度的におよそ２倍以上になっており、１回あたりの使用量の増加度合いが大きい。
【００３２】
洗浄液中の無機塩の標準濃度設定については、性能面、環境対応面、コスト面等、いくつかの観点があるが、洗浄力について実用上問題の無い最小濃度で設定するのが妥当であると考えられる。すなわち、日本のような低硬度水、低温洗濯の条件下において、本発明の粉末洗浄剤の場合、およそ３０〜６０ｇ／３０Ｌ洗濯用水の使用濃度、換言すれば１〜２ｇ／リットル（以下、「Ｌ」と省略する場合がある。）の使用濃度が相当である。
【００３３】
なお、本発明の弱アルカリ性無機塩洗浄液は、本願出願人が先に出願し公開され、引用によりその開示が明細書中に取り込まれる、特再平１１−８３７４１４号公報、または特再２０００−８２０５４９号公報に開示されている、重曹（重炭酸ナトリウムまたは炭酸水素ナトリウムと言う場合がある。）水溶液を電気分解することによって生成させた、炭酸イオン、重炭酸イオンを含んだｐＨが９〜１１のアルカリ性無機塩水溶液をも含むものである。
１−３）洗濯用水の軟水化：
水道水や井戸水などに含まれるカルシウムイオン、マグネシウムイオンをはじめとする多価陽イオン（硬度成分）は洗浄液中において、表面が負に帯電した汚れと繊維の両方に橋渡しをする形で両者を引き付けてしまい、繊維表面に汚れを付着させる原因の一つとなる。本発明の無機塩洗浄剤では、これら多価陽イオンが洗浄液中に含まれる炭酸イオンと結びつき、洗浄液中に不溶の炭酸塩を生成することで多価陽イオンに由来する洗浄力阻害要因を減少させる。不溶性炭酸塩の生成過程を通じて炭酸イオンは消費されるが、炭酸アルカリ金属塩の濃度が多価陽イオンの濃度と比較してはるかに大きいため、界面活性剤が働くために必要なできるだけ少ないビルダー量で硬度成分に対応するという考え方の合成洗剤と、本発明の洗浄剤を比較したとき、本発明の洗浄剤では、洗濯用水の硬度によって受ける影響は少ない。ただし、洗濯用水の硬度成分の量が極めて多い地域では、本発明の洗浄剤の炭酸イオン量、すなわち洗浄剤濃度を十分に高めることで洗浄力を確保することが必要となる。
【００３４】
硬度成分の無効化すなわち軟水化の進行は、本発明の洗浄剤を溶解した洗浄液が置かれる状況、条件により次のように変化する。これを表５に示す。
【００３５】
【表５】

表５によれば、そのまま放置した場合反応はゆっくりと進み、洗浄力向上に有効な低硬度まで低下するにはおよそ３時間を要する。しかし溶解希釈後に攪拌等の物理力を加えた場合、反応は促進されおよそ３０分で同程度まで低下する。さらに布を入れて攪拌した場合は５分〜１０分まで早まる。このような特性は洗濯において都合が良い。これらの反応促進要素は、洗濯機による通常の洗濯において与えられる物理的作用と同じであるから、特別な操作を加えることなく軟水化の促進が行われることになる。
【００３６】
ここで、攪拌等の機械力は洗浄液中の多価陽イオンと炭酸イオンの接触機会を増すという面で有効であり、超音波振動や加熱による分子運動の増加も同様の効果がある。また、布等の衣料を入れた場合の反応促進は布表面に付着する微細な炭酸カルシウムが触媒的に作用しているものと考えられる。
【００３７】
洗濯用水の硬度がさらに高い場合、その硬度に比例して軟水化時間が長くなるように思われるが、実際には初期硬度が高いほど硬度の低下率は大きくなるため、布を入れて攪拌した場合では初期硬度にかかわらずほぼ１５分経過時点で同等の硬度まで低下する。
【００３８】
なお、実際の洗濯においては洗浄液中の硬度成分は洗濯用水中に含まれるもののみでは無く、すすぎ時に被洗物に付着したものや、人体からの汗に含まれるもの、付着した汚れに含まれるものなどの合計量であり、それらは徐々に溶出してくるため洗浄液の硬度は一定値以下にはならず、また洗い時間を長くした場合などは逆に洗浄液中の硬度が増加する場合もある。
【００３９】
ここで、洗浄液濃度を一定（０．８ｇ／Ｌ）としたときのｐＨと軟水化効果の関係について調べてみる。
【００４０】
まず、主剤としての炭酸ナトリウムと重炭酸ナトリウムの混合比率を変えていくことでｐＨを変化させ、このときの硬度低下時間変化について調べた。その結果を表６に示す。
【００４１】
【表６】

表６によれば、ｐＨ９．３と９．８の間で大きな変化があり、ｐＨは高い方が硬度低下時間の短縮につながることがわかるが、ｐＨ９．８を超えたところでは頭打ちとなる。この結果から、硬度を効率的に低下させるにはｐＨをおよそ９．５以上に設定するのがよいことがわかる。
【００４２】
したがって、洗浄力の観点に加えて軟水化速度の観点からも、洗浄液のｐＨは９．５以上が好ましい。
【００４３】
このように本洗浄剤においてはその主成分が洗浄力阻害要因となる硬度成分と反応しこれを無効化する作用があるため、合成洗剤成分として通常使用される有機系のキレート剤や水不溶性のゼオライトなどの軟水化剤をとくに加えることなく、実用的な軟水化効果を得ることができる。しかし、本洗浄剤にキレート剤等の軟水化剤を加えて更なる性能向上を図る場合は、先に述べたような方法で軟水化促進を行い、一定時間経過後にキレート剤等の軟水化剤を途中添加することにより、少量の軟水化剤でより効果的に軟水化促進を図ることができる。ただしゼオライトのように反応時間が比較的長いものの場合、途中添加を前提として８〜１２分程度の所定の洗い時間内に同様の効果を出すことは難しい。その他の軟水化剤としては分解性や安全性の面から脂肪酸石鹸を好適に用いることができる。この場合目的は軟水化にあるので、洗浄力を発揮するほどの量の添加は必要ない。また、洗浄液にアルカリ成分が含まれるため、脂肪酸塩の代わりにオレイン酸等の脂肪酸を添加し、洗浄液中で金属石鹸を生成させる方法を用いることもできる。
（２）再汚染防止成分
合成洗剤では、界面活性剤に、洗浄力のみならずそれ自体で十分な分散性（再汚染防止性）があるが、さらに再汚染防止性能を向上させるために少量の再汚染防止剤を添加することがよく行われる。とくに固体粒子汚れの分散性が脱落した汚れの布への再付着性（再汚染性）と関連しており、多くの界面活性剤は固体粒子汚れに吸着し、これらを分散する性能を有している。
【００４４】
しかし本発明の無機塩の場合、そのような固体粒子を分散する作用はほとんど期待できないため、このもの単独の洗浄液では、固体粒子汚れのほか油汚れや疎水性汚れが存在しかつ複合化している実際の洗濯系において、衣料への付着乃至再汚染はもちろん、洗濯槽への付着も避けられないこととなる。
【００４５】
一般に、再汚染防止の機構としては、汚れの可溶化、分散化、繊維と汚れの電気的斥力などの種々が考えられる。本発明者らは、本発明の無機塩洗浄剤について再汚染防止性能の付与を目的として鋭意研究を進めた結果、再汚染が洗浄液の表面張力の高いときに生じ、かつ、ごく僅かな表面張力の低下（およそ５８ｄｙｎ／ｃｍ以下）によって再汚染がかなり防止され得ることをつきとめた。しかし、それは主として親水性繊維に対する再汚染防止であり、本発明においてより十分な再汚染防止性能を得るには、さらに疎水性繊維や非極性汚れへの吸着能すなわちそれらを分散する性能も必要であることを知見した。また、無機塩を主洗浄作用成分とする本発明の洗浄液系においては、元来イオン含量が大きいため、静電気的な斥力を期待した再汚染防止成分の添加は効果的でなく、問題となるのは、静電的吸着が起こらない非極性固体汚れ粒子、あるいは固体汚れ粒子と疎水性汚れの混合物であり、さらには疎水性繊維への再汚染防止であることを知った。
【００４６】
したがって、本発明において必要とされる再汚染防止性能を得るためには、（１）洗浄液の表面張力を上記所定の表面張力以下に低下させる性能（表面張力低下能と呼ぶ）、および（２）　疎水性繊維や非極性汚れに吸着して汚れを分散する性能（以下、疎水性再汚染防止能と呼ぶ。）の双方を具備することが望ましい。
【００４７】
ここで「所定の」表面張力低下能とは、本発明の無機塩洗浄剤を、洗濯時の標準的な洗浄液濃度である実使用濃度１ｇ／Ｌ（０．１重量％）に水で溶解して得られる洗浄液について、同洗浄液の表面張力を５８ｄｙｎ／ｃｍ以下に低下させる能力をいう。そうした本洗浄液に作用する表面張力低下能について、実用的な再汚染防止性能を期するために必要な限界を確認すること等を目的とする「墨汁試験」を行った。本墨汁試験では、各濃度での本発明洗浄液のそれぞれに少量の墨汁を滴下したときの墨汁のふるまいを観察し、表面に広がって洗濯槽内壁を汚染する（表面張力低下作用なし）か、又は、洗浄液表面に対して鉛直に落下或いは洗浄液中に分散する（表面張力低下作用あり）かによって、本発明洗浄液各濃度下での表面張力低下作用の有無を判定する。この結果を表７に示す。
【００４８】
【表７】

表７の結果からも、本発明洗浄液の表面張力を５８ｄｙｎ／ｃｍ以下に低下させることができれば、一定の再汚染防止能を発揮することが可能であることが裏付けられた。
【００４９】
なお、本発明において使用される再汚染防止成分としては、再汚染防止剤として通常用いられる水溶性高分子物質の範疇に属するもののみならず、本発明の洗浄液系に臨界ミセル濃度以下の量で配合されて上記所定の表面張力低下作用を有する界面活性剤を使用することをも含む。
【００５０】
次に、本発明に使用できる再汚染防止成分の範囲を探索するために、既存の合成洗剤における標準的な界面活性剤濃度（陰イオン系）の約１／１０以下を目安とした量である、本発明の洗浄液中でおよそ０．０１７ｇ／Ｌ濃度となるように（３０Ｌの洗濯用水に再汚染防止成分を０．５ｇ添加溶解したときの成分濃度に相当）各種再汚染防止物質（分散剤と呼ぶ場合がある。）を同洗浄液中に添加し、このときの再汚染防止性能を評価した。なお、本発明の洗浄剤組成物の成分組成は、無機塩主剤２８．６ｇ＋各再汚染防止物質０．５ｇであり、さらに無機塩主剤の成分組成は、炭酸ナトリウム１０ｇ＋炭酸水素ナトリウム７．８ｇ＋メタケイ酸ナトリウム５水和物１０．８ｇである。被検衣料として木綿及びポリエステル繊維の２種を用い、汚れとして一定量の墨汁を滴下して、被検洗浄液中で洗ったときの洗濯前後の白度差を比較した。なお、本再汚染防止性能評価試験は、後述する再汚染試験条件に準じた条件で試験を行っている。その結果を表８〜表１０に示す。
【００５１】
【表８】

【００５２】
【表９】

【００５３】
【表１０】

その結果、各種再汚染防止物質は、（ａ）前記表面張力低下能及び前記疎水性再汚染防止能があり、その物質単独かつ低濃度で十分な再汚染防止効果があるもの、（ｂ）前記表面張力低下能または前記疎水性再汚染防止能のいずれか一方を有するのみで、単独では本発明の再汚染防止成分として用いることができないが、それらの中でお互いを補うように組み合わせて、あるいは上記（ａ）の分散剤と組み合わせて、実用的な再汚染防止効果を得ることができるもの、（ｃ）従来の合成洗剤と同程度の濃度にしなければ効果が得られない、もしくは無機塩洗浄剤系では再汚染防止効果は得られないもの、の３つのグループに分かれた。
【００５４】
本発明の再汚染防止成分として用いることができる分散剤は、上記したように、単独使用も可能な（ａ）グループ、及び他と組み合わせることにより使用できる（ｂ）グループのものである。
【００５５】
（ａ）グループに属するものとしては、メチルセルロース、ヒドロキシプロピルセルロース、ヒドロキシプロピルメチルセルロース、ヒドロキシエチルメチルセルロース、部分鹸化ポリビニルアルコール、ポリプロピレングリコール、ポリオキシエチレンポリオキシプロピレンブロックコポリマー等の非イオン性水溶性高分子物質もしくは非イオン性界面活性剤が挙げられる。
【００５６】
一方、（ｂ）グループに属するものとしては、ポリアクリル酸ナトリウム、ポリエチレングリコール、ヒドロキシエチルセルロース、カルボキシメチルセルロース、ポリビニルピロリドン等の水溶性高分子物質、ポリオキシエチレンソルビタンモノオレート、ポリオキシエチレンソルビタンモノラウレート、ポリグリセリン脂肪酸エステル、エチレングリコール、ラウリルアミドプロピル酢酸ベタイン等の非イオンもしくは両性界面活性剤などが挙げられる。
【００５７】
（ａ）グループに属するものは少量で洗浄液の表面張力をおよそ５８ｄｙｎ／ｃｍ以下に低下させる作用を有しており、さらに疎水性繊維や非極性汚れへの吸着性、分散性も良好であると言える。なお、前記疎水性再汚染防止能がよいものは、概ね親水性繊維や極性汚れへの吸着性、分散性も良好である。
【００５８】
（ｂ）グループに属するものには、表面張力低下能はあるが分散能の弱い非イオン性もしくは両性の分散剤と、分散能はあるが表面張力低下能がないアニオン性分散剤と、があり、親水性繊維や極性の汚れには比較的効果があるが、疎水性繊維や非極性汚れにはほとんど効果を示さず、木綿及び化学繊維（ポリエステル）の両者について少量で再汚染防止性能を得るといった前提では、（ｂ）グループに属するもの単独では十分な再汚染防止性能を得ることは難しい傾向がある。
【００５９】
（ａ）グループに属するものの再汚染防止性能は濃度の増加とともによくなっていくが、実用的に必要なできるだけ低い濃度範囲で使用することが、環境負荷低減等の観点から好ましい。なお、これらの再汚染防止物質は濃度をいくら高くしても表面張力の低下は頭打ちとなり、また洗浄力にも濃度による影響はほとんどない。
【００６０】
それらのことをポリビニルアルコールについて試験した例で示す（表１１参照）。
【００６１】
【表１１】

さらに、部分鹸化型ポリビニルアルコールの再汚染防止性能について、重合度のパラメータを変えたときの影響を示す。（表１２参照）。
【００６２】
【表１２】

表１２によれば、部分鹸化型ポリビニルアルコール（ＰＶＡ）のうち、重合度が１０００程度のものまでは良好な結果が得られている。
【００６３】
さらに、疎水基の影響を見るために、親水基ポリオキシエチレンと疎水基ポリオキシプロピレンの各分子量構成比をさまざまに変えることができるプルロニックについて試験して図２の結果を得た。
【００６４】
図２の再汚染防止性能評価結果より、疎水基の大きさ（分子量）が３０００を超えたもので良好な効果を示している。全体の分子量（総分子量）はグリッドの右・上方向に大きくなるが、総分子量が同じでも疎水基の小さいものはほとんど効果がないことから、疎水基の大きさが重要であると考えられる。また疎水基の大きさが同じ場合は、親水基の総分子量に占める割合が小さいほど疎水性繊維に対しての再汚染防止能が向上している。換言すると、疎水基の大きさが同じであれば、総分子量は小さいほうが疎水性繊維に対して有利であると言える。
【００６５】
以上の知見から、本発明において再汚染防止成分として好適に使用できるのは水溶性高分子物質であり、このうちさらに好ましく使用できる物質は、概ね非イオン性であること、疎水性で大きな疎水基部分があること、の２つの条件を満足する物質である。このうちさらに好ましく使用できる物質は、その平均分子量が１０００〜５０万程度の比較的低分子量の物質、より好ましくは数千程度の物質である。また、安全性や生分解性の面からはセルロース系、多価アルコール系、脂肪酸系などが好ましく、具体的にはメチルセルロース、ヒドロキシプロピルセルロース、ヒドロキシプロピルメチルセルロース、ヒドロキシエチルメチルセルロース、部分鹸化型ポリビニルアルコールなどが特に好ましい。
【００６６】
また、衣料には親水性繊維と疎水性繊維があり、再汚染防止成分のそうした繊維との相性もあって、十分な再汚染防止性能を得るためには、（ａ）グループの物質の単独使用よりも、上記の（ａ）グループ内の物質同士の組み合わせ、もしくは（ａ）グループの物質と（ｂ）グループの物質の組み合わせが有効なことが多く、前者の（ａ）グループ内の物質同士の中での二種以上の適切な組み合わせが最も好ましい。
【００６７】
表１３に各種再汚染防止成分の組み合わせにつき評価した結果を示す。
【００６８】
【表１３】

表１３より、（ａ）グループの再汚染防止物質のうち、木綿に対して比較的よい結果を示すものとポリエステル繊維に対してよい結果を示すものとをうまく組み合わせると、それぞれより少ない量で親水性繊維と疎水性繊維に対しバランスよく再汚染防止効果を発揮させ得ることがわかる。なかでも、部分鹸化型ポリビニルアルコールとヒドロキシプロピルメチルセルロースの１：１の組み合わせで特に良好な結果が得られた。
【００６９】
本発明の洗浄剤組成物において、再汚染防止成分の総量は洗浄剤組成物総量の１０重量％以下であることが好ましい。
【００７０】
そして、再汚染防止性能が実用的な水準に達していることを条件に、再汚染防止成分の総量が洗浄剤組成物総量の９重量％以下であることがさらに好ましく、以下同様に、同８重量％以下、同７重量％以下、同６重量％以下、同５重量％以下、同４重量％以下、同３重量％以下、同２重量％以下、同１重量％以下の順序で、洗浄剤組成物中における再汚染防止成分の配合量が少ないほど望ましい。
【００７１】
本発明において、水溶性高分子等の再汚染防止成分は重要な役割を担っているものの有機物であり、そうした有機物の量はできるだけ少ないほうが、環境負荷を減らす本発明の目的に添うからである。
【００７２】
また、本発明の無機洗浄剤組成物を標準的な使用を想定した１ｇ／Ｌになるように水で溶解して得られる洗浄液中における再汚染防止成分濃度は少なくとも０．００７ｇ／Ｌ（０．０００７重量％、３０Ｌの洗濯用水に再汚染防止成分を０．２ｇ溶解したときの成分濃度に相当）以上であり、好ましくは０．０１ｇ／Ｌ（０．００１重量％、３０Ｌの洗濯用水に再汚染防止成分を０．３ｇ溶解したときの成分濃度に相当）以上である。また、本発明の洗浄剤組成物中の無機塩配合比率を９０重量％としたとき、再汚染防止成分の同組成物中における配合比率の上限は１０重量％となるので、このことから前記洗浄液中における再汚染防止成分濃度は０．１ｇ／Ｌ（０．０１重量％、３０Ｌの洗濯用水に再汚染防止成分を３ｇ溶解したときの成分濃度に相当）が上限となる。
【００７３】
さらに、先に述べたように、本発明の無機塩洗浄主剤成分の一つであるケイ酸アルカリ金属塩は、（ａ）グループに属する再汚染防止物質ほどの効果はないが、再汚染防止効果の向上に寄与することができるので、これを併用することで、（ａ）グループに属する有機系再汚染防止物質の使用量を減少させることができる。
【００７４】
重炭酸塩と炭酸塩との組み合わせに係る無機塩主剤に、ケイ酸塩もしくは有機系再汚染防止物質を加えていったときの再汚染防止性能の向上を確認した。メタケイ酸ナトリウムを主剤中の炭酸ナトリウムと同じ重量比率で置き換えていき、配合比率を徐々に増加させていったときの再汚染防止能を評価した。なお、有機系再汚染防止物質の量は一定とした。
【００７５】
【表１４】

この結果より、メタケイ酸ナトリウム（５水和物として）は洗浄剤総量の３０〜７０重量％が好ましい。
【００７６】
このように水溶性ケイ酸塩と（ａ）グループに属する再汚染防止物質を併用することにより、洗浄液に含まれる有機系再汚染防止成分の下限濃度は０．００７ｇ／Ｌ（０．０００７重量％）程度まで引き下げられて、非常に低い濃度で実用的な再汚染防止効果を得ることができる。これは、従来の合成洗剤等に比べて１／１０以下の有機物使用量に相当する。
（３）添加剤
本発明の洗浄剤は、本発明の趣旨を逸脱しない範囲において、必要に応じて、洗濯用酵素、酸素系漂白剤、殺菌剤、香料、軟水化剤、起泡剤など合成洗剤等に常用成分として含まれる物質をさらに含んでもよい。
【００７７】
これら添加剤のうち、最も重要なものは洗濯用酵素である。アルカリ性無機塩主剤及び再汚染防止成分を含有する本発明の洗浄系では今ひとつ取りきれない汚れをも取り去るために有用である。洗濯用酵素としては、タンパク質分解酵素（プロテアーゼ）、脂肪分解酵素（リパーゼ）、セルロース分解酵素（セルラーゼ）、デンプン分解酵素（アミラーゼ）などがあるが、なかでもプロテアーゼは日常汚れに対して特に効果的であり、セルラーゼは繰り返し洗濯した場合に木綿繊維の白さ維持や固体粒子汚れの除去等に効果があり実用性が高い。
【００７８】
酵素の配合量は洗浄剤組成物総量に対して１酵素あたりおよそ０．３％から３重量％程度でよい。
【００７９】
また、本洗浄剤の液性は弱アルカリ性であるので、酵素の配合を検討するにあたってはそのｐＨ範囲において活性値が低下しないものを選択しなければならない。逆に、ｐＨ範囲は、アルカリ塩による洗浄力のみを考慮して設定するのではなく、組成物中に配合される酵素の活性が十分に発揮されることも考慮したｐＨ範囲とすることが望ましい。
【００８０】
なお、酵素の洗浄剤への配合において特に注意すべき点は、洗浄液中での酵素活性の安定性であり、特に洗濯用水中に含まれる有効遊離塩素による失活には注意しなければならない。また本発明の洗浄剤は炭酸塩を主成分の一つとするが、炭酸塩が有効遊離塩素による酸化反応を促進する作用があるため、特に注意が必要である。
【００８１】
したがって、洗浄剤中への配合においては酵素と還元剤を同時に添加する必要がある。還元剤としては亜硫酸塩、チオ硫酸塩が適当であるが、活性塩素をトラップして酵素の失活を防止するものとして硫酸アンモニウム塩などのアンモニウム塩を用いる方法もある。これらの配合量は洗浄剤組成物総量に対して０．３％から３重量％程度がよい。
【００８２】
酸素系漂白剤としては、過炭酸ナトリウム、過ホウ酸ナトリウム、過酸化水素などを挙げることができる。本発明の洗浄剤組成物は酸素系漂白剤を使用しなくても従来の界面活性剤を主剤とした合成洗剤と同等の洗浄力を発揮するが、漂白剤を加えることでさらに洗浄性能の向上が期待できる。
【００８３】
殺菌剤は、被洗浄物の殺菌の他、有機物を含む洗浄剤組成物の腐敗やカビを防ぐ効果を目的として配合され、塩化ベンザルコニウムやパラベン、プロピレングリコールなどのなかからその使用目的に応じて適宜選択することができる。人体への安全性を考慮すると、柑橘類果実の種子から抽出した抽出液を添加することが望ましい。ここで、柑橘類果実とは、学術名をシトラスパラデシとする、グレープフルーツであり、抽出液自体は高粘性であるため、添加する際には水で希釈するとともに、天然のグリセリン、プロピレングリコールなどの分散剤を用いることが好ましい。シトラスパラデシの種子の抽出液は、細菌や微生物の殺菌、抗菌等の制菌効果があるため、本発明の洗浄剤組成物に制菌添加剤として添加すると、被洗浄物の制菌効果が期待できる。その他の殺菌剤として、お茶の葉や竹などから得られる天然殺菌剤を配合してもよい。
（４）洗浄剤組成物の製造方法
本発明の洗浄剤組成物はその原料がほとんどすべて粉末もしくは粒状物であり、それらを均一に混合しさえすればよいため、種々の方法で種々の剤形に容易に製造できる。最も簡単で、経済的な製造方法は、それら粉体原料を公知のバッチ式の混合機で攪拌混合するのみで粉末もしくは粒状の本発明の洗浄剤組成物が製造される。
【００８４】
使い勝手から１回使用量毎の錠剤型やシート型にすることができる。また、本発明の洗浄剤組成物は粉体原料と水を混合して濃縮液体型の洗浄剤として製造することももとより可能である。
【００８５】
なお、洗濯槽内に貯められた炭酸水素ナトリウム水溶液を例えば循環式又はバッチ式に電気分解することにより、本発明の弱アルカリ無機塩洗浄液を生成する場合には、上述したケイ酸塩や水溶性高分子物質を含む再汚染防止成分等を粉末もしくは水溶液等の形態で別途後添加すればよい。
（５）洗浄液
本発明は、基本的には、主たる洗浄作用成分としてのアルカリ性緩衝系を形成する無機塩洗浄作用成分と、再汚染防止成分とからなり、界面活性剤を実質的に含有しない洗浄液により洗濯する衣料の洗濯方法に関する。また、洗浄液にさらに洗濯用酵素を存在させれば洗濯性能を一層向上させることができる。
【００８６】
前記したように、本発明におけるアルカリ性無機塩は、重炭酸アルカリ金属塩と、炭酸アルカリ金属塩及び／又はケイ酸アルカリ金属塩とを主成分として含有することが好ましい態様であり、日本の洗濯条件では、本発明の洗浄液には、アルカリ性無機塩総量としておよそ１〜２ｇ／Ｌ（０．１〜０．２重量％）の濃度で溶解されているのが好ましい。そして、重炭酸アルカリ金属塩と炭酸アルカリ金属塩とは、含有モル数で１：７乃至１：０．２の比率で存在するのが好ましく、重炭酸アルカリ金属塩とケイ酸アルカリ金属塩とは、含有モル数で１：１．２乃至１：０．１の比率で存在するのが好ましい。また、これらを３成分系で存在させるとき、洗浄力の観点からは、ケイ酸アルカリ金属塩は炭酸アルカリ金属塩と任意に置き換えることができる。なお、ケイ酸塩はｐＨや溶解性、総使用量低減および製造コストの観点から、メタケイ酸ナトリウムの５水和物が好ましい。
【００８７】
主としてアルカリ性無機塩緩衝系により決まる本発明の洗浄液（１ｇ／Ｌ濃度）が呈するｐＨは、洗浄力及び軟水化速度等の観点から９．５〜１１が好ましく、１０〜１０．６がさらに好ましい。
【００８８】
また、本発明の無機洗浄液中における一方の重要成分である（有機系）再汚染防止成分の総量は０．０１ｇ／Ｌ（０．００１重量％）以上が好ましい。そして、再汚染防止性能をも有するメタケイ酸ナトリウム（５水和物）を洗浄剤組成物総量の３０〜７０重量％用いるときには、洗浄液に含まれる有機系再汚染防止成分濃度として０．００７ｇ／Ｌ（０．０００７重量％）以上とすることができる。
【００８９】
日本のように、低硬度水での低温洗浄といった一般的な洗濯条件においては、本発明に係る洗浄液の実使用濃度は、０．５〜５ｇ／Ｌ（０．０５〜０．５重量％）の範囲に収まる。なお、こうした範囲の実使用濃度が、請求の範囲でいう実使用濃度に相当し、０．５ｇ／Ｌ（０．０５重量％、３０Ｌの洗濯用水に洗浄剤組成物を１５ｇ溶解したときの濃度に相当）程度まで薄められた使用濃度は軽い汚れの衣料を洗う際に用いられ、また、５ｇ／Ｌ（０．５重量％、３０Ｌの洗濯用水に洗浄剤組成物を１５０ｇ溶解したときの濃度に相当）程度までの高められた使用濃度はたとえば浸け置き洗いや高硬度洗濯用水地域で洗濯を行う際に用いられ、これら低濃度と高濃度の中間濃度領域においては、洗濯すべき衣料の量や洗濯用水容量などに応じて適宜の濃度が用いられる。そして、こうした実使用濃度範囲において本発明の洗浄剤は既存の洗濯石鹸や合成洗剤とほぼ同等以上の洗濯性能を発揮する。
【００９０】
以下に、本発明の標準的組成の粉末洗浄剤組成物につき、その投入量と洗浄液のｐＨの関係を示す。
【００９１】
炭酸ナトリウム１１２ｇ、重炭酸ナトリウム６０ｇ、メタケイ酸ナトリウム５水和物１１０ｇ、その他添加剤１８ｇを配合して洗浄剤総量の重量を３００ｇにした配合比率の洗浄剤組成物を用いて、３０リットルの水に溶解したときの、０．５〜５ｇ／Ｌ（０．０５〜０．５重量％）の範囲における各濃度での、それぞれの洗浄液が呈するｐＨ値（２５°Ｃ）は次のようである。すなわち、０．０５重量％（粉末洗浄剤組成物の投入量は１５ｇ／３０Ｌ）で１０．３９、０．１０重量％（同投入量は３０ｇ）で１０．６４、０．１５重量％（同投入量は４５ｇ／３０Ｌ）で１０．７３、０．２０重量％（同投入量は６０ｇ／３０Ｌ）で１０．７８、０．２５重量％（同投入量は７５ｇ／３０Ｌ）で１０．７９、０．３０重量％（同投入量は９０ｇ／３０Ｌ）で１０．８０、０．５０重量％（同投入量は１５０ｇ／３０Ｌ）で１０．８９である。
【００９２】
【発明の作用及び効果】
本発明によれば、人体への安全性や環境負荷低減の観点から疑問がある界面活性剤を使用することのない、または界面活性剤の使用量を大幅に削減した洗浄剤組成物であって、酵素や漂白剤入りの洗剤と同等もしくはそれ以上の洗浄力と使い勝手を有し、かつ、とくに再汚染防止性能に優れた、無機塩主剤の洗浄剤組成物を提供することができる。また、本発明にかかる衣料の洗濯方法、衣料用洗浄剤組成物、および再汚染防止剤によれば、不潔を嫌う清潔志向と、洗剤成分の衣料への残留を嫌う健康志向との、一見矛盾する現代日本の消費者ニーズの両者を、きわめて高い水準で充足することができる。
【００９３】
アルカリ金属の重炭酸塩と炭酸塩及び／又はケイ酸塩とを水で溶解し、特定のｐＨ及び濃度範囲に設定すると、アルカリ剤による油脂汚れ等の鹸化、分解等による洗浄効果が得られる。また、重炭酸塩が共存する緩衝系であるため、炭酸塩及び／又はケイ酸塩のアルカリ作用塩を多く入れることができて洗浄液のイオン強度が高くなるので、固体汚れと被洗濯物表面の双方に陰イオンが吸着することで、電気的斥力が働いて、固体汚れが被洗濯物表面から離れやすくなる。さらには、水中に含まれるカルシウムイオンやマグネシウムイオンなどの、従来の洗濯系では洗浄力阻害要因である硬度成分は炭酸塩となり、炭酸塩の発生ないし凝集の過程で生じるコロイド状の炭酸カルシウムが洗浄液中の汚れ粒子を吸着し、洗浄性能を向上させることにもなる。
【００９４】
ケイ酸塩、とくにメタケイ酸ナトリウムは、水溶液中においてコロイドを生じ、無機汚れ粒子の吸着乃至洗浄液中への分散作用を本質的に有していて、繊維への汚れ粒子の吸着、つまり再汚染を防止する効果もある。炭酸塩及び重炭酸塩を主成分とする洗浄剤組成物をケイ酸塩と組み合わせるとき、洗浄力を損なうことなく炭酸塩と任意の割合で置き換えることが可能である。
【００９５】
こうした主たる洗浄作用が無機塩により得られる洗浄剤組成物に、メチルセルロース、ヒドロキシプロピルセルロース、ヒドロキシプロピルメチルセルロース、ヒドロキシエチルメチルセルロース、部分鹸化型ポリビニルアルコール等の表面張力低下作用及び疎水性繊維の再汚染防止能を有する水溶性高分子物質をごく少量添加することで、アルカリ性無機塩洗浄剤の普及を妨げている主要因であった再汚染防止性能を大幅に向上させて、その洗濯性能を合成洗剤なみの実用的なレベルとすることができる。この表面張力を低下させる作用等を有する水溶性高分子物質は、とくに再汚染しやすくこれを防止し難いポリエステルなどの化学繊維に対して有効であり、上記メタケイ酸ナトリウムをも含む他の再汚染防止成分とを併用することにより、再汚染防止成分全体の添加量をさらに低くできる。
【００９６】
【発明を実施するための最良の形態】
以下、本発明の洗浄剤組成物もしくは洗浄液を従来の洗浄剤組成物及びその洗浄液と比較した具体例を説明する。ただし、以下に示す具体的数値は本発明の洗浄剤組成物の使用により得られる洗濯性能の一部を例示的に開示するものであって、本発明を限定する趣旨ではない。なお、本明細書中に開示した洗浄力試験に係る実施例又は比較例について、洗浄力は使用する汚染布のロット番号の相違にしたがって変化する場合があるので、汚染布のロット番号が相互に異なる試験間での単なる数値の比較は出来ない場合があることを付言しておく。
洗浄力試験その１
洗浄力試験その１の説明に先立って、その試験条件を明らかにしておく。
【００９７】
洗浄力試験条件
洗濯機は、株式会社東芝製の全自動洗濯機（ＡＷ−Ｃ６０ＶＰ、６ｋｇタイプ、水位設定３１リットル、負荷としてタオル２ｋｇ）を用い、水温２０℃の水道水（藤沢市市水道、ｐＨ７．５、ＥＣ１９ｍＳ／ｍ）で洗いを１２分、すすぎを１回、脱水を５分実施した。
【００９８】
この洗濯機に、「人工皮脂」が付着した人工汚染布（Ｓｃｉｅｎｔｉｆｉｃ　Ｓｅｒｖｉｃｅｓ　Ｓ／Ｄ　ｉｎｃ．　ＵＳＡ製、綿と混紡の２種）３枚及び鉱物油とカーボンブラックが付着した汚染布（ＥＭＰＡ１０１）、オリーブ油とカーボンブラックが付着した汚染布（ＥＭＰＡ１０６）、血液が付着した汚染布（ＥＭＰＡ１１１）、タンパク質であるカカオが付着した汚染布（ＥＭＰＡ１１２）、赤ワインが付着した汚染布（ＥＭＰＡ１１４）、血液とミルクとカーボンブラックが付着した汚染布（ＥＭＰＡ１１６）の各３枚をタオルに縫い付けて洗濯した。なお、「洗浄率」は下記の式により算出した。
【００９９】
洗浄率％＝（洗濯後汚染布の白度−洗濯前汚染布の白度）÷（未汚染生地の白度−洗濯前汚染布の白度）×１００
ここで、「白度」は白度計（ミノルタ株式会社製、ＣＲ−１４、Ｗｈｉｔｅｎｅｓｓ　Ｉｎｄｅｘ　Ｃｏｌｏｒ　Ｒｅａｄｅｒ）により、３枚の汚染布それぞれの相互に異なる表裏１０点の測定値を平均した。
【０１００】
なお、本明細書中に開示している洗浄力試験は、特にことわらない限り本試験条件に則して行われていることを付け加えておく。
【０１０１】
実施例１
水道水３１リットルに、炭酸ナトリウム９ｇ、炭酸水素ナトリウム１０ｇ、メタケイ酸ナトリウム（９水和物）２２ｇ、メチルセルロース０．２ｇ、ポリビニルアルコール０．２ｇの各成分組成からなり、同成分総量が４１．４ｇの洗浄剤を溶解して、洗浄剤濃度が１．３４ｇ／Ｌ、ｐＨが１０．６の洗浄液を得た。この洗浄液を用いて洗濯したときの洗濯前後における各汚染布の洗浄率を測定した。結果を表１５に示す。
【０１０２】
実施例２
水道水３１リットルに、炭酸水素ナトリウム１６ｇ、メタケイ酸ナトリウム（９水和物）４０ｇ、メチルセルロース０．２ｇ、ポリビニルアルコール０．２ｇの各成分組成からなり、同成分総量が５６．４ｇの洗浄剤を溶解して、洗浄剤濃度が１．８２ｇ／Ｌ、ｐＨが１０．６洗浄液を得た。この洗浄液を用いて洗濯したときの洗濯前後における各汚染布の洗浄率を測定した。結果を表１５に示す。
【０１０３】
実施例３
水道水３１リットルに、炭酸ナトリウム１８ｇ、炭酸水素ナトリウム８ｇ、メチルセルロース０．２ｇ、ポリビニルアルコール０．２ｇの各成分組成からなり、同成分総量が２６．４ｇの洗浄剤を溶解して、洗浄剤濃度が０．８５ｇ／Ｌ、ｐＨが１０．３の洗浄液を得た。この洗浄液を用いて洗濯したときの洗濯前後における各汚染布の洗浄率を測定した。結果を表１５に示す。
【０１０４】
実施例４
実施例１の洗浄液に、さらに酵素としてのプロテアーゼを０．３ｇおよびセルラーゼを０．１ｇ、還元剤としての亜硫酸ナトリウム０．６ｇの各成分をそれぞれ加えて溶解させた以外は実施例１と同様にして汚染布の洗浄率を測定した。結果を表１５に示す。
【０１０５】
実施例５
実施例１の洗浄液に、さらに酵素としてのプロテアーゼを０．３ｇおよびセルラーゼを０．１ｇ、還元剤としての亜硫酸ナトリウムを０．６ｇ、漂白剤としての過炭酸ナトリウム６ｇの各成分をそれぞれ加えて溶解させた以外は実施例１と同様にして汚染布の洗浄率を測定した。結果を表１５に示す。
【０１０６】
比較例１
実施例１乃至５の比較例として、水道水３１リットルに、炭酸ナトリウム１８ｇ、炭酸水素ナトリウム８ｇの各成分組成からなり、同成分総量が２６ｇの洗浄剤を溶解して、洗浄剤濃度が０．８４ｇ／Ｌ、ｐＨが１０．４の洗浄液を得た。この洗浄液を用いて実施例１と同様にして汚染布の洗浄率を測定した。結果を表１５に示す。
【０１０７】
比較例２
実施例１乃至５の比較例として、市販の粉石鹸を標準濃度で水道水に溶解させた洗浄液（洗浄剤濃度１ｇ／Ｌ、ミヨシ石鹸製造（株）社製）を用いて、実施例１と同様にして汚染布の洗浄率を測定した。この結果を表１５に示す。
【０１０８】
比較例３
実施例１乃至５の比較例として、市販の液体合成洗剤を標準濃度で水道水に希釈溶解させた洗浄液（液体アタック、洗浄剤濃度２０ｍＬ／３１Ｌ、花王株式会社製、酵素・漂白剤の配合なし）を用いて、実施例１と同様にして汚染布の洗浄率を測定した。この結果を表１５に示す。
【０１０９】
比較例４
実施例１乃至５の比較例として、市販の粉末合成洗剤を標準濃度で水道水に溶解させた洗浄液（ニュービーズ、洗浄剤濃度０．８ｇ／Ｌ、花王株式会社製、酵素および漂白剤入り）を用いて、実施例１と同様にして汚染布の洗浄率を測定した。この結果を表１５に示す。
【０１１０】
比較例５
実施例１乃至５の比較例として、市販の粉末合成洗剤を標準濃度で水道水に溶解させた洗浄液（アタック、０．６５ｇ／Ｌ、花王株式会社製、酵素および漂白剤入り）を用いて、実施例１と同様にして汚染布の洗浄率を測定した。この結果を表１５に示す。
【０１１１】
【表１５】

実施例１〜５の洗浄率と比較例２〜５の洗浄率を比べても明らかなように、本実施例の無機塩を洗濯主剤として再汚染防止成分を含む洗浄液は、何れも市販の界面活性剤を洗濯主剤とする洗濯石鹸または合成洗剤とほぼ同等又はそれ以上の洗浄力を示している。このうち、実施例４〜５と比較例２〜５とを比べると、酵素及び還元剤や漂白剤をさらに添加した実施例４、５のものは総合的に従来の洗濯石鹸または合成洗剤と同等又はそれ以上の洗浄力を示し、特にタンパク質汚れを対象とした洗浄力に優れていることが理解できる。
【０１１２】
なお、実施例１〜３と比較例１とを比べると、実施例にて添加したメチルセルロースやポリビニルアルコールなどの、表面張力低下作用を有する水溶性高分子物質は、１回洗浄の本試験における洗浄率ではほとんどその効果は認められない。
【０１１３】
さらに、実施例１及び２と実施例３とを比べると、メタケイ酸ナトリウムと炭酸ナトリウムとを置き換えても、洗浄率はほぼ同等であることが理解できる。
再汚染試験その１
再汚染試験その１を次述の試験条件で実施し、再汚染防止効果を確認した。
【０１１４】
再汚染試験条件
洗濯機は、シャープ株式会社製の二槽式洗濯機（ＥＳ−２５Ｅ、水位設定３０リットル、負荷としてタオル１．５ｋｇ）を用い、水温２０℃の水道水（藤沢市市水道、ｐＨ７．２、ＥＣ１５．５ｍＳ／ｍ）で洗いを１０分、流水すすぎを４分、脱水を５分実施した。
【０１１５】
この洗濯機に、再汚染の疑似汚れとしての墨汁を０．４５ｇ滴下し、木綿およびポリエステルの白布（５ｃｍ角）の各３枚をタオルに縫い付け下記の汚染布とともに洗濯した。
【０１１６】
再汚染評価は、上述した木綿およびポリエステルの白布（５ｃｍ角）各３枚の洗濯前後の白度を測定することで行った。評価数値としての再汚染度は、洗浄後の白度から洗浄前の白度を減じた値とした。再汚染度が正のときは洗浄後の方がより白くなっていることを意味し、負のときは洗浄後に再汚染されて白度が低下したことを意味する。したがって、再汚染度がゼロ若しくは正の値（ただし、ポリエステルの場合は−１以上）であれば再汚染防止性能は実用上問題ないと判断できる。
【０１１７】
なお、本明細書中に開示している再汚染試験は、特にことわらない限り本試験条件に則して行われていることを付け加えておく。
【０１１８】
実施例６
実施例１にて得られた洗浄液を用いて洗濯し、このときの再汚染度を計算により求めた。その結果を表１６に示す。
【０１１９】
実施例７
実施例２で得られた洗浄液を用いて実施例６と同様の条件で再汚染を評価した。結果を表１６に示す。
【０１２０】
実施例８
実施例３で得られた洗浄液を用いて実施例６と同様の条件で再汚染を評価した。結果を表１６に示す。
【０１２１】
比較例６
実施例６〜８の比較例として、比較例１で得られた洗浄液を用いて実施例６と同様の条件で再汚染を評価した。結果を表１６に示す。
【０１２２】
比較例７
実施例６〜８の比較例として、水道水３１リットルに、炭酸ナトリウム９ｇ、炭酸水素ナトリウム１０ｇ、メタケイ酸ナトリウム（９水和物）２２ｇの各成分組成からなり、同成分総量が４１ｇの洗浄剤を溶解して、洗浄剤濃度が１．３２ｇ／Ｌ、ｐＨが１０．６の洗浄液を得た。この洗浄液を用いて実施例６と同様の条件で再汚染を評価した。結果を表１６に示す。
【０１２３】
比較例８
実施例６〜８の比較例として、比較例３の洗浄液を用いて実施例６と同様の条件で再汚染を評価した。結果を表１６に示す。
【０１２４】
【表１６】

この結果からも明らかなように、水溶性高分子物質を添加しないと再汚染度が大きく実用に耐えない（比較例６，７参照）が、水溶性高分子物質を添加した実施例６〜８の洗浄液は、最も再汚染防止効果が低いもの（実施例８）でも、比較例６，７以上の再汚染防止性能を発揮する。
【０１２５】
実施例６〜８を比べると、洗浄剤中のメタケイ酸ナトリウムの含有量が多くなるほど再汚染防止性能が高くなることが理解できる。
再汚染試験その２
実施例９
水道水３１リットルに、炭酸ナトリウム９ｇ、炭酸水素ナトリウム１０ｇ、メタケイ酸ナトリウム（９水和物）２２ｇ、メチルセルロース０．４ｇの各成分組成からなり、同成分総量が４１．４ｇの洗浄剤を溶解して、洗浄剤濃度が１．３４ｇ／Ｌ、ｐＨが１０．６の洗浄液を得た。この洗浄液を用いて実施例６と同様の条件で再汚染を評価した。結果を表１７に示す。
【０１２６】
実施例１０
水道水３１リットルに、炭酸ナトリウム９ｇ、炭酸水素ナトリウム１０ｇ、メタケイ酸ナトリウム（９水和物）２２ｇ、ポリビニルアルコール０．４ｇの各成分組成からなり、同成分総量が４１．４ｇの洗浄剤を溶解して、洗浄剤濃度が１．３４ｇ／Ｌ、ｐＨが１０．６の洗浄液を得た。この洗浄液を用いて実施例６と同様の条件で再汚染を評価した。結果を表１７に示す。
【０１２７】
実施例１１
水道水３１リットルに、炭酸ナトリウム９ｇ、炭酸水素ナトリウム１０ｇ、メタケイ酸ナトリウム（９水和物）２２ｇ、ヒドロキシプロピルセルロース０．４ｇの各成分組成からなり、同成分総量が４１．４ｇの洗浄剤を溶解して、洗浄剤濃度が１．３４ｇ／Ｌ、ｐＨが１０．７の洗浄液を得た。この洗浄液を用いて実施例６と同様の条件で再汚染を評価した。結果を表１７に示す。
【０１２８】
実施例１２
水道水３１リットルに、炭酸ナトリウム９ｇ、炭酸水素ナトリウム１０ｇ、メタケイ酸ナトリウム（９水和物）２２ｇ、ヒドロキシプロピルセルロース０．２ｇ、ポリエチレングリコール０．２ｇの各成分組成からなり、同成分総量が４１．６ｇの洗浄剤を溶解して、洗浄剤濃度が１．３４ｇ／Ｌ、ｐＨが１０．７の洗浄液を得た。この洗浄液を用いて実施例６と同様の条件で再汚染を評価した。結果を表１７に示す。
【０１２９】
実施例１３
水道水３１リットルに、炭酸ナトリウム９ｇ、炭酸水素ナトリウム１０ｇ、メタケイ酸ナトリウム（９水和物）２２ｇ、ＬＴ０．４５ｇ、カルボキシメチルセルロース０．１５ｇの各成分組成からなり、同成分総量が４１．６ｇの洗浄剤を溶解して、洗浄剤濃度が１．３４ｇ／Ｌ、ｐＨが１０．６の洗浄液を得た。この洗浄液を用いて実施例６と同様の条件で再汚染を評価した。結果を表１７に示す。
【０１３０】
比較例９
実施例９〜１３の比較例として、水道水３１リットルに、炭酸ナトリウム９ｇ、炭酸水素ナトリウム１０ｇ、メタケイ酸ナトリウム（９水和物）２２ｇの各成分組成からなり、同成分総量が４１ｇの洗浄剤を溶解して、洗浄剤濃度が１．３２ｇ／Ｌ、ｐＨが１０．６の洗浄液を得た。この洗浄液を用いて実施例６と同様の条件で再汚染を評価した。結果を表１７に示す。
【０１３１】
【表１７】

無機塩主剤成分組成の配合比率と量を一定として、再汚染防止剤の種類と量を各種組み合わせて比較した本再汚染試験その２の結果からも明らかなように、水溶性高分子物質を単独で添加する場合は、木綿及び化学繊維（ポリエステル）のバランスを考慮すると、ポリビニルアルコール（実施例１０参照）が最も良好な再汚染防止性能を発揮することがわかる。
洗浄力試験その２
洗浄力試験その２を、洗浄力試験その１に準じた試験条件で実施し、既存の合成洗剤および洗濯石鹸との間で洗浄性能を比較確認した。
【０１３２】
実施例１４
水道水３１リットルに、下記の各成分組成からなる本発明の洗浄剤Ａ（酵素無配合）３０ｇを、３０Ｌの洗濯用水に溶解させて得られる洗浄液を用いて洗濯したときの洗濯前後における各汚染布の洗浄率を測定した。その結果を表１８に示す。

実施例１５
水道水３１リットルに、下記の各成分組成からなる本発明の洗浄剤Ｂ（酵素配合）３０ｇを、３０Ｌの洗濯用水に溶解させて得られる洗浄液を用いて洗濯したときの洗濯前後における各汚染布の洗浄率を測定した。その結果を表１８に示す。

比較例１０
実施例１４〜１５の比較例として、市販の液体合成洗剤を標準濃度で水道水に希釈溶解させた洗浄液（洗浄剤濃度２０ｍＬ／３１Ｌ、酵素配合）を用いて、実施例１４と同様にして汚染布の洗浄率を測定した。この結果を表１８に示す。
【０１３３】
比較例１１
実施例１４〜１５の比較例として、市販の粉末合成洗剤を標準濃度で水道水に溶解させた洗浄液（０．６５ｇ／Ｌ、酵素及び蛍光増白剤配合）を用いて、実施例１４と同様にして汚染布の洗浄率を測定した。この結果を表１８に示す。
【０１３４】
比較例１２
実施例１４〜１５の比較例として、市販の液体洗剤を標準濃度で水道水に溶解させた洗浄液（アトピー患者用、界面活性剤９％配合）を用いて、実施例１４と同様にして汚染布の洗浄率を測定した。この結果を表１８に示す。
【０１３５】
比較例１３
実施例１４〜１５の比較例として、市販の粉末純石鹸を標準濃度で水道水に溶解させた洗浄液（洗浄液濃度１ｇ／Ｌ）を用いて、実施例１４と同様にして汚染布の洗浄率を測定した。この結果を表１８に示す。
【０１３６】
上記実施例１４、１５及び比較例１０〜１３について洗浄力試験を行った結果を表１８に示す。
【０１３７】
【表１８】

実施例１４〜１５の洗浄率と、比較例１０〜１３の洗浄率を比べても明らかなように、本実施例の無機塩を洗濯主剤として再汚染防止成分を含む洗浄液は、何れも市販の界面活性剤を洗濯主剤とする洗濯石鹸または合成洗剤とほぼ同等又はそれ以上の洗浄力を示している。このうち、実施例１４〜１５と比較例１０〜１３とを比べると、酵素及び還元剤をさらに添加した実施例１５のものは総合的に従来の洗濯石鹸または合成洗剤と同等又はそれ以上の洗浄性能を示し、特にタンパク質汚れを対象とした洗浄力に優れていることがわかる。
再汚染試験その３
再汚染試験その３を、再汚染試験その１に準じた試験条件で実施し、既存の合成洗剤および洗濯石鹸との間で再汚染防止性能を比較確認した。
【０１３８】
実施例１６
水道水３１リットルに、実施例１４と同様の各成分組成からなる本発明の洗浄剤Ａ（酵素無配合）３０ｇを、３０Ｌの洗濯用水に溶解させて得られる洗浄液を用いて洗濯し、このときの再汚染度を計算により求めた。その結果を表１９に示す。
【０１３９】
実施例１７
水道水３１リットルに、実施例１５と同様の各成分組成からなる本発明の洗浄剤Ｂ（酵素配合）３０ｇを、３０Ｌの洗濯用水に溶解させて得られる洗浄液を用いて洗濯し、このときの再汚染度を計算により求めた。その結果を表１９に示す。
【０１４０】
比較例１４
実施例１６〜１７の比較例として、比較例１０と同様の洗浄液を用いて洗濯し、このときの再汚染度を計算により求めた。その結果を表１９に示す。
【０１４１】
比較例１５
実施例１６〜１７の比較例として、比較例１１と同様の洗浄液を用いて洗濯し、このときの再汚染度を計算により求めた。その結果を表１９に示す。
【０１４２】
比較例１６
実施例１４〜１５の比較例として、比較例１２と同様の洗浄液を用いて洗濯し、このときの再汚染度を計算により求めた。その結果を表１９に示す。
【０１４３】
比較例１７
実施例１４〜１５の比較例として、比較例１３と同様の洗浄液を用いて洗濯し、このときの再汚染度を計算により求めた。その結果を表１９に示す。
【０１４４】
【表１９】

本発明の無機塩洗浄剤と組み合わせて使用することを前提とし、各種再汚染防止物質の単独もしくは組み合わせ使用を想定した性能評価試験を行うことで得られた知見をもとに選択した、ＰＶＡ（ポリビニルアルコール）とＨＰＭＣ（ヒドロキシプロピルメチルセルロース）の組み合わせに係る再汚染防止剤を含有する本発明の洗浄液は、本再汚染試験その３の結果からも明らかなように、酵素の配合有無とは相関することなく、木綿及び化学繊維（ポリエステル）の両者について、いずれも市販の界面活性剤を洗濯主剤とする洗濯石鹸または合成洗剤とほぼ同等又はそれ以上の再汚染防止性能を示していることがわかる。
ＣＯＤ／ＢＯＤ分析試験
本発明の洗浄剤を実使用濃度である１ｇ／Ｌ（０．１重量％）に水で溶解して得られる洗浄液と、市販の粉末合成洗剤を標準濃度に水で溶解して得られる洗浄液と、について、ＣＯＤ及びＢＯＤの分析試験結果を表２０に示す。なお、本分析試験はＪＩＳの「工場排水試験法」に則して行った。
【０１４５】
【表２０】

表２０の分析試験結果から、本発明の洗浄剤から得られる洗浄液は、市販の粉末合成洗剤から得られる洗浄液と比較して、ＣＯＤ及びＢＯＤともにほぼ１／２０であり、したがって、既存の合成洗剤に代えて本発明の洗浄剤を衣料用洗濯に使用すれば、環境負荷の大幅な低減を期せることがわかる。
魚毒性試験
水棲生物としてめだかを使用し、このめだかの飼育水として、市販の粉末合成洗剤を水に溶解して得られる洗浄液（標準濃度：０．７ｇ／Ｌ（０．０７重量％））と、粉末純石鹸を水に溶解して得られる洗浄液（標準濃度：１ｇ／Ｌ（０．１重量％））と、本発明の洗浄剤を水に溶解して得られる洗浄液（標準濃度：１ｇ／Ｌ（０．１重量％））とを、各洗浄液について標準、５倍希釈、２５倍希釈の各濃度に設定した洗浄液を用意し、各洗浄液内でめだかを１Ｌあたり１匹の割合で１０匹飼育し、その生存率の時間変化を観察した魚毒性試験結果を表２１に示す。
【０１４６】
【表２１】

表２１の魚毒性試験結果から、本発明の洗浄液は、市販の粉末合成洗剤や粉末純石鹸から得られる洗浄液と比較して、水棲生物に対してもきわめて安全性の高いものといえる。
使用薬剤の特定
本明細書中で開示した使用薬剤については下記のものを使用した。
炭酸ナトリウム：ソーダ灰　（株）トクヤマ
重炭酸ナトリウム：重炭酸ナトリウム　東ソー（株）
メタケイ酸ナトリウム：メタ珪酸ソーダ５水和物　Ｎａ_２Ｏ　２８〜３０％、ＳｉＯ_２　２７〜２９％　日本化学（株）
亜硫酸ナトリウム：無水亜硫酸ソーダ　大東化学（株）
メチルセルロース：メトローズＳＭ　ＭＣ４００　信越化学工業（株）
ヒドロキシプロピルセルロース：ＨＰＣ　Ｍ−タイプ　（株）トクヤマ
ヒドロキシプロピルメチルセルロース：メトローズＳＨ　ＳＥＢ−０４Ｔ　信越化学工業（株）
ヒドロキシエチルメチルセルロース：メトローズＳＥ　ＳＮＢ−３０Ｔ　信越化学工業（株）
ポリビニルアルコール：ポバール　ＰＡ−０５Ｓ　信越化学工業（株）
重合度３５００　部分ケン化型
重合度１０００　部分ケン化型
重合度５００　　部分ケン化型　和光純薬工業（株）　試薬
ポリプロピレングリコール：
トリオール　分子量４０００　和光純薬工業（株）
ジオール　　分子量３０００　和光純薬工業（株）
プルロニック：アデカプルロニック（Ｌ３１、Ｌ３４、Ｌ６１、Ｌ６４、Ｆ６８、Ｌ１０１、Ｐ１０３、Ｆ１０８）　旭電化工業（株）
酵素１：プロテアーゼ　Ｐｒｏｐｅｒａｓｅ１０００Ｅ　ナガセケムテックス（株）
酵素２：セルラーゼ　ｃｅｌｌｕｚｙｍｅ０．７Ｔ　ノボザイムスジャパン（株）
界面活性剤：
ノニオン　（ＯＴ−２２１、ＬＴ−２２１）　日本油脂（株）
ラウリルアミドプロピル酢酸ベタイン　ＰＢ−３０Ｌ　旭電化工業（株）
ポリグリセリン脂肪酸エステル　ＣＰＧ−１５０　旭電化工業（株）
ポリエチレングリコールオレート　ＯＥＧ−１０６　旭電化工業（株）

【０１４７】
【産業上の利用可能性】
本発明の洗浄剤組成物は、アルカリ性無機塩を洗浄主剤とし、実質的に界面活性剤を使用することのない洗浄剤組成物であって、従来の界面活性剤を主剤とした洗濯石鹸または合成洗剤と同等もしくはそれ以上の洗浄力及び使い勝手を有するものである。
【０１４８】
以上に述べた本発明は、明らかに同一性の範囲に属するものが多種存在する。そのような多様性は発明の意図及び範囲から離脱したものとはみなされず、当業者に自明であるそのようなすべての変更は、本発明に係る請求の範囲の技術的射程範囲内に含まれる。
【図面の簡単な説明】
【図１】図１は本発明に係る洗浄液の濃度パラメータを変化させたときの洗浄率変化を示す図である。
【図２】図２はプルロニックによる再汚染防止性能評価結果を示す図である。[0001]
【Technical field】
The present invention relates to a method for washing clothes in which an alkaline inorganic salt is used as a washing agent, and a detergent composition therefor.
[0002]
[Background Art]
Synthetic detergents have been overwhelmingly supported in laundry washing due to their excellent detergency and ease of use. However, synthetic detergents do not only benefit consumers. For example, although synthetic detergents have undergone repeated improvement processes due to environmental load problems caused by sodium alkylbenzene sulfonate and phosphate builder incorporated therein, in recent years, some of these have become potential environmental hormones. As a result, problems such as effects on living things have begun to be raised. In addition, it is an undeniable fact that the surfactant contained in the synthetic detergent remains in a considerable amount of clothing even after rinsing, and it cannot be denied that such a surfactant has any effect on the human body through the skin. . Furthermore, the large amount of water discarded during multiple rinsings aimed at removing the surfactant cannot be wasted as a valuable resource.
[0003]
Soap that has been used for a long time and is considered to be good in terms of safety cannot be a substitute even for those who question the safety of synthetic detergents due to its poor usability. In addition, although soap is more biodegradable than synthetic detergents, it is not likely to lead to a reduction in environmental load in view of the large amount of soap used.
[0004]
Although excellent cleaning performance with surfactants is widely recognized, considering the impact on living organisms and the environment, cleaning with no surfactant added or with a significantly reduced amount of surfactant used There is a need for a new detergent which is equivalent to a synthetic detergent in terms of washing performance and usability.
[0005]
As a detergent for clothing mainly containing an alkaline inorganic salt without adding a surfactant, laundry soda (sodium carbonate hydrate) is used as a single agent in the old days. As disclosed in Japanese Patent No. 87678, there has been proposed a composition in which an enzyme is further added to sodium bicarbonate (baking soda) in order to enhance the detergency.
[0006]
However, these conventionally known detergents containing an alkaline inorganic salt as a main component are inferior in washing performance and ease of use as compared with laundry soaps and synthetic detergents, and are far from synthetic detergents. Was.
[0007]
The present invention relates to a detergent composition that does not substantially use a surfactant that is questionable from the viewpoint of safety to the human body and a reduction in environmental load, or that significantly reduces the amount of the surfactant used. Accordingly, it is an object of the present invention to provide a detergent composition which can provide washing performance and operability equivalent to or higher than conventional laundry soaps or synthetic detergents containing a surfactant as a main component, and a washing method using the same.
[0008]
DISCLOSURE OF THE INVENTION
In view of the above-mentioned object, the present inventors have conducted a thorough study focusing on a cleaning agent whose main cleaning action is obtained by an alkaline inorganic salt, that is, an alkaline inorganic salt as a washing action main agent. In the cleaning agent, the composition of the alkaline inorganic salt was inappropriate, and furthermore, as a major factor, there was almost no re-contamination prevention performance, which hindered the realization of practical washing performance. I came to think.
[0009]
That is, the washing effect (sometimes referred to as washing performance) in the washing of clothing is based on the detergency of separating dirt from the clothing, and the ability to prevent the dirt dispersed in the cleaning liquid from re-adhering to the clothing and soiling the clothing. Both pollution control performance is obtained. If the re-contamination prevention performance is insufficient, the purpose of washing is not sufficiently fulfilled due to re-contamination when washing heavyly soiled laundry, and dirt accumulates through repeated washing when washing lightly soiled laundry. This leads to graying of clothing, and the washing effect must be said to be insufficient.
[0010]
The present inventors have paid attention to such problems in the alkaline inorganic salt detergent, mainly studied the composition of the alkaline inorganic salt detergent and the re-contamination inhibitor, and further considered some additives, thereby substantially reducing the amount of additives. A detergent composition which does not use a surfactant for the washing agent, and has a washing performance and a operability equivalent to or higher than that of a conventional laundry detergent or a synthetic detergent containing a surfactant as a main component, and an alkali inorganic salt as a main component. It has been found that a detergent composition and a washing method using the same can be provided, and the present invention has been completed.
(1)Alkaline inorganic salt detergent
ADVANTAGE OF THE INVENTION According to this invention, the washing | cleaning composition for clothing containing an inorganic salt which forms an alkaline buffer system as a main washing | cleaning action component, and also containing at least a re-contamination prevention component is provided.
1-1)Composition of alkaline inorganic salt:
The alkaline inorganic salt in the present invention contains, as main components, a pH buffering salt that mainly plays a role of a pH buffering action and an alkaline action salt that mainly plays a role of an alkali action. When the detergent composition of the present invention is dissolved in water for washing, the pH of the washing solution at a standard concentration is in the range of slightly alkaline of 9 to 11, without damaging the fiber and improving the user's ability. It is possible to wash with sufficient safety.
[0011]
Generally, in washing clothes, high detergency is required within a weak alkaline range of pH 9 to 11. However, since the pH of the alkaline agent depends on the concentration, the concentration used must be low to converge the pH within such a weak alkaline range, and as a result, sufficient detergency cannot be obtained. Was. The data as shown in Table 1 were obtained for pH, concentration and detergency.
[0012]
[Table 1]

According to Table 1, when the alkali salt is used alone, a sufficient concentration is not obtained in a pH range of 10 or less, so that the detergency is about the same as that of a sodium hydrogen carbonate aqueous solution having a pH of about 8.3. On the other hand, in the case of a system in which baking soda is mixed instead of the alkali salt alone system, by increasing the concentration even at a relatively low pH in the pH range of 9 or more, it is possible to obtain the same detergency as when the pH is high. I understand.
[0013]
Therefore, when a pH buffering salt such as sodium bicarbonate coexists, a buffer system is formed, and the concentration of the alkali agent can be sufficiently increased while suppressing the promotion of alkalization accompanying the increase in the concentration of the alkali acting salt.
[0014]
In an aqueous solution of carbonate or bicarbonate, the abundance ratio of -2 bivalent carbonate ions and -1 valent bicarbonate ions depends on the pH of the aqueous solution. At pH 10.3, the abundance ratio is approximately 1: 1. In the high pH region, the amount of carbonate ions increases, and in the low pH region, the bicarbonate ions further change to carbon dioxide gas. Also, the higher the abundance ratio of bicarbonate ions, the stronger the buffering action, and the pH hardly changes even if the concentration is changed. Therefore, by mixing carbonate (carbonate ion) and bicarbonate (bicarbonate ion), it is possible to obtain an arbitrary weakly alkaline pH, increase the concentration of the alkali agent, and reduce the pH change due to the alkali agent concentration. It can be a cleaning solution (see Table 2).
[0015]
[Table 2]

Furthermore, even if, for example, acidic stains are mixed in the washing liquid, the pH buffering salt acts to suppress the promotion of acidification of the washing liquid, so that the washing liquid is converged and maintained in a weakly alkaline range suitable for washing. The effect that can be done can also be expected.
[0016]
The pH buffering salt in the present invention includes, for example, alkali metal bicarbonate, alkali metal borate, alkali metal phosphate and the like, and organic salts such as alkali metal oxalate and alkali metal phthalate. Acid salts can also be used supplementarily. Further, examples of the alkali action salt in the present invention include an alkali metal carbonate and an alkali metal silicate.
[0017]
In the present invention, the inorganic salt preferably contains an alkali metal bicarbonate and an alkali metal carbonate and / or an alkali metal silicate as main components. As described above, the main role of the alkali metal bicarbonate is a pH buffering action, and the main role of the alkali metal carbonate and the alkali silicate is the promotion of the alkaline alkalinity of the cleaning solution.
[0018]
In addition, the composition of the alkaline inorganic salt of the present invention basically contains an alkali metal bicarbonate in order to utilize its pH buffering action. Since the system has the detergency required for the present invention and has some buffering action, it is included in the category of the alkaline inorganic salt composition of the present invention.
[0019]
In addition, the alkali metal carbonate also has a good water softening promoting action as described later, while the alkali silicate has an improved re-contamination preventing ability and a rust preventing action on the metal surface of the washing machine. Also, it has an action of preventing the hardness component from sticking to the drainage system.
[0020]
Alkali metal silicates, especially sodium metasilicate, form colloids in the washing liquid and have an effect of adsorbing inorganic dirt particles or dispersing them in the washing liquid. To prevent Further, in the detergent composition of the present invention, an alkali metal silicate, particularly sodium metasilicate (pentahydrate), can be replaced with sodium carbonate at an arbitrary ratio without impairing the detergency.
[0021]
In order to impart sufficient re-contamination prevention performance, it is desirable to set the concentration of the alkali metal silicate to 0.001 mol / liter or more in the cleaning solution.
[0022]
In the present invention, the blending ratio of the total amount of the inorganic salt to the total amount of the detergent composition is preferably 90% by weight or more. The inorganic salt compounding ratio must be 91% by weight or more, provided that a re-soil prevention substance described below is present so that the re-soil prevention ability reaches a level comparable to that of existing laundry soaps and synthetic detergents. More preferably, similarly, 92% by weight or more, 93% by weight or more, 94% by weight or more, 95% by weight or more, 96% by weight or more, 97% by weight or more, 98% by weight or more, In the order of 99% by weight or more, it is preferable that the amount of the inorganic salt in the detergent composition is larger. This is because the effect of improving the detergency by the main agent is obtained.
[0023]
In the present invention, the molar ratio of the alkali metal bicarbonate to the molar ratio of the alkali metal carbonate is more preferably from 1: 7 to 1: 0.2. In the present invention, in order to avoid various harms such as fiber damage, skin damage and necessity of drainage treatment caused by the tendency of the liquid property of the washing solution to be strongly alkaline, alkali metal bicarbonate as a pH buffering salt is used. Is contained as an essential component to converge the pH of a washing solution (for example, 1 g / L (0.1% by weight) concentration) during washing to 9 to 11, which is a weakly alkaline range. The ratio of the number of moles of the alkali metal bicarbonate to the number of moles of the alkali metal carbonate that can form is equivalent to 1: 7 to 1: 0.2.
[0024]
In the case of a combination of an alkali metal bicarbonate and an alkali metal silicate, a molar ratio of 1: 1.2 to 1: 0.1 is similarly preferable.
[0025]
Further, when three kinds of alkali metal salts of an alkali metal bicarbonate, an alkali metal carbonate, and an alkali metal silicate are used in combination as the inorganic salt forming the alkaline buffer system as the main cleaning action component, an alkali silicate is used. Taking into account the re-contamination prevention performance of a metal salt, for example, sodium metasilicate, etc., the alkali metal silicate is used in an amount of 20 to 90% by weight, preferably 30 to 70% by weight based on the total weight of the detergent. Is preferably set.
[0026]
The total amount of the inorganic salts and the mixing ratio of the alkali metal bicarbonate and the alkali metal carbonate and / or the alkali metal silicate are determined according to the type of laundry targeted by the detergent composition and the target for sale. An appropriate ratio can be selected in accordance with the washing conditions such as the hardness of the water in the area to be washed, the washing temperature, the type of washing machine, and the like. For example, for washing of perishable clothing, the alkalinity should be as low as possible, that is, the ratio of alkali metal bicarbonate should be as high as possible. It is preferable to mix a large amount of the alkali metal carbonate at a high ratio.
[0027]
When sodium salts are used as the alkali metal bicarbonate and the alkali metal carbonate in the combination of the inorganic salts, sodium sesquicarbonate, which is an equimolar mixture of these substances, can be replaced within the above-mentioned composition ratio.
1-2)Washing solution pH and inorganic salt concentration:
The pH of the washing solution can be adjusted by the mixing ratio of the alkali metal bicarbonate, for example, sodium bicarbonate in the base mixture. The relationship between pH and detergency was examined using a cleaning solution in which a mixture of sodium carbonate and sodium bicarbonate, which is the simplest configuration, was dissolved in tap water. Table 3 shows the results.
[0028]
[Table 3]

From Table 3, no significant difference is observed up to about pH 9.3 as compared with tap water alone, but a significant increase in the cleaning rate is observed from around pH 9.5. On the higher pH side, the washing rate is still increasing in a weakly alkaline range, but the upper limit of the preferred pH can be determined by considering the compatibility with the enzyme to be added.
[0029]
Therefore, from the viewpoint of detergency, the pH of the cleaning solution when the cleaning composition of the present invention is dissolved in water at a standard use concentration, for example, 1 g / L (0.1% by weight) is preferably 9.5 or more. .
[0030]
Next, Table 4 and FIG. 1 show the relationship between the inorganic salt concentration in the cleaning solution of the present invention and the detergency.
[0031]
[Table 4]

Although the washing rate tends to increase as the inorganic salt concentration increases, almost no increase is observed from a certain point. Further, as a feature of the present cleaning agent, there are two “shelf” in which a change in the cleaning rate is almost flat. There is a relatively large difference between the cleaning rates of the first shelf and the second shelf, and the higher the concentration, the higher the cleaning rate. However, the concentration is about twice or more, and the amount of use per use is large.
[0032]
Regarding the standard concentration setting of inorganic salts in the washing liquid, there are several viewpoints such as performance, environmental compatibility, cost, etc., but it is appropriate to set the minimum concentration at which there is no practical problem with the washing power. Conceivable. That is, under the conditions of low hardness water and low temperature washing as in Japan, in the case of the powder detergent of the present invention, the usage concentration of about 30 to 60 g / 30 L of washing water, in other words, 1 to 2 g / liter (hereinafter, referred to as “ L "may be abbreviated.).
[0033]
In addition, the weak alkaline inorganic salt washing liquid of the present invention is disclosed in Japanese Patent Publication No. 11-873414 or Japanese Patent Publication No. 2000-820549, which was filed and published by the present applicant, and the disclosure of which is incorporated herein by reference. No. 5,009,098, which contains carbonate ions and bicarbonate ions and is formed by electrolysis of an aqueous solution of sodium bicarbonate (sometimes referred to as sodium bicarbonate or sodium bicarbonate). It also includes an alkaline inorganic salt aqueous solution.
1-3)Water softening for washing:
Polyvalent cations (hardness components) such as calcium ions and magnesium ions contained in tap water and well water attract the two in the cleaning solution by bridging both the stain and the fibers with negatively charged surfaces. This is one of the causes of attaching dirt to the fiber surface. In the inorganic salt detergent of the present invention, these polyvalent cations are combined with the carbonate ions contained in the cleaning solution to form insoluble carbonate in the cleaning solution, thereby reducing the detergency inhibiting factor derived from the polyvalent cations. Let it. Although carbonate ions are consumed during the process of producing insoluble carbonate, the concentration of alkali metal carbonate is much higher than the concentration of polyvalent cations, so the amount of builder necessary for the surfactant to work is as small as possible. When the detergent of the present invention is compared with the synthetic detergent having the concept of corresponding to the hardness component, the detergent of the present invention is less affected by the hardness of the washing water. However, in an area where the amount of the hardness component of the washing water is extremely large, it is necessary to secure the detergency by sufficiently increasing the carbonate ion amount of the detergent of the present invention, that is, the detergent concentration.
[0034]
The inactivation of the hardness component, that is, the progress of water softening, changes as follows depending on the conditions and conditions in which the cleaning solution in which the cleaning agent of the present invention is dissolved is placed. This is shown in Table 5.
[0035]
[Table 5]

According to Table 5, when left as it is, the reaction proceeds slowly, and it takes about 3 hours to reduce to a low hardness effective for improving the detergency. However, when a physical force such as stirring is applied after dissolution dilution, the reaction is accelerated and decreases to about the same level in about 30 minutes. When a cloth is further stirred, the time is advanced from 5 minutes to 10 minutes. Such characteristics are advantageous in washing. Since these reaction promoting elements are the same as the physical action given in normal washing by a washing machine, the water softening is promoted without any special operation.
[0036]
Here, mechanical force such as stirring is effective in increasing the chance of contact between polyvalent cations and carbonate ions in the cleaning liquid, and the increase in molecular motion due to ultrasonic vibration or heating has the same effect. In addition, it is considered that the promotion of the reaction when clothing such as cloth is put is caused by the catalytic action of fine calcium carbonate adhering to the cloth surface.
[0037]
If the hardness of the washing water is even higher, it seems that the water softening time is longer in proportion to the hardness, but in practice, the higher the initial hardness, the greater the rate of decrease in the hardness, so a cloth was added and stirred. In this case, regardless of the initial hardness, the hardness decreases to the same hardness after approximately 15 minutes.
[0038]
In the actual washing, the hardness component in the washing liquid is not only contained in the washing water, but also contained in the object to be washed at the time of rinsing, contained in the sweat from the human body, and contained in the attached dirt. The hardness of the cleaning solution does not fall below a certain value because they gradually elute, and the hardness in the cleaning solution may increase when the washing time is prolonged. .
[0039]
Here, the relationship between the pH and the water softening effect when the concentration of the washing liquid is constant (0.8 g / L) will be examined.
[0040]
First, the pH was changed by changing the mixing ratio of sodium carbonate and sodium bicarbonate as the main agent, and the change in hardness reduction time at this time was examined. Table 6 shows the results.
[0041]
[Table 6]

According to Table 6, there is a large change between pH 9.3 and 9.8, and it can be seen that a higher pH leads to a shorter hardness reduction time, but reaches a peak when the pH exceeds 9.8. From these results, it can be seen that it is better to set the pH to about 9.5 or more in order to reduce the hardness efficiently.
[0042]
Therefore, the pH of the cleaning solution is preferably 9.5 or more from the viewpoint of water softening rate in addition to the viewpoint of detergency.
[0043]
As described above, in the present detergent, the main component thereof reacts with the hardness component which is a deterrent to the detergency, and has an effect of invalidating it. Therefore, the organic chelating agent usually used as a synthetic detergent component or water-insoluble A practical water softening effect can be obtained without particularly adding a water softening agent such as zeolite. However, when further improving the performance by adding a water softener such as a chelating agent to the present cleaning agent, the water softening is promoted by the method described above, and after a certain period of time, the water softening agent such as the chelating agent is used. Is added in the middle, water softening can be promoted more effectively with a small amount of water softener. However, when the reaction time is relatively long, such as zeolite, it is difficult to achieve the same effect within a predetermined washing time of about 8 to 12 minutes on the assumption that the reaction is added during the reaction. As the other water softener, fatty acid soap can be suitably used from the viewpoint of decomposability and safety. In this case, since the purpose is to soften water, it is not necessary to add an amount sufficient to exert detergency. In addition, since the washing solution contains an alkali component, a method of adding a fatty acid such as oleic acid instead of the fatty acid salt to generate a metal soap in the washing solution can be used.
(2)Recontamination prevention component
In a synthetic detergent, a surfactant has not only detergency but also sufficient dispersibility (anti-soil repellency) by itself, but a small amount of an anti-soil redeposition agent is added to further improve the anti-soil redeposition performance. That is often done. In particular, the dispersibility of solid particulate soil is related to the re-adhesion (recontamination property) of the detached soil to the cloth, and many surfactants have the ability to adsorb to solid particulate soil and disperse them. ing.
[0044]
However, in the case of the inorganic salt of the present invention, since such an action of dispersing solid particles can hardly be expected, in the case of a single washing liquid, oil stains and hydrophobic stains other than solid particle stains are present and are complexed. In an actual laundry system, it is inevitable that the toner adheres or re-contaminates the clothes and also adheres to the washing tub.
[0045]
In general, various mechanisms for preventing recontamination can be considered, such as solubilization and dispersion of dirt, and electrical repulsion between fibers and dirt. The present inventors have conducted intensive studies on the inorganic salt detergent of the present invention for the purpose of imparting re-contamination prevention performance. As a result, re-contamination occurs when the surface tension of the cleaning solution is high, and the surface tension is very small. Has been found that recontamination can be significantly prevented by a reduction in (less than about 58 dyn / cm). However, it is mainly the prevention of re-contamination of hydrophilic fibers, and in order to obtain a sufficient re-contamination prevention performance in the present invention, the ability to adsorb hydrophobic fibers and non-polar stains, that is, the ability to disperse them is also required. I found that there was. Further, in the cleaning liquid system of the present invention containing an inorganic salt as a main cleaning component, since the ion content is originally large, the addition of a re-contamination-preventing component that expects electrostatic repulsion is not effective and poses a problem. Was found to be non-polar solid soil particles in which electrostatic adsorption does not occur, or a mixture of solid soil particles and hydrophobic soil, and to prevent recontamination of hydrophobic fibers.
[0046]
Therefore, in order to obtain the re-contamination prevention performance required in the present invention, (1) a performance of lowering the surface tension of the cleaning liquid to the predetermined surface tension or less (referred to as a surface tension lowering ability), and (2) It is desirable to have both the ability to adsorb to hydrophobic fibers and non-polar stains to disperse the stains (hereinafter referred to as hydrophobic re-soil prevention ability).
[0047]
Here, the “predetermined” surface tension lowering ability means that the inorganic salt detergent of the present invention is dissolved in water to a standard working solution concentration of 1 g / L (0.1% by weight), which is a standard washing solution concentration for washing. Refers to the ability to reduce the surface tension of the cleaning liquid to 58 dyn / cm or less. With respect to the ability to lower the surface tension acting on such a cleaning solution, a "black ink test" was conducted for the purpose of, for example, confirming the necessary limit for ensuring practical recontamination prevention performance. In the present ink test, the behavior of the ink when a small amount of ink was dropped on each of the cleaning liquids of the present invention at each concentration was observed. The presence or absence of the surface tension lowering effect at each concentration of the cleaning solution of the present invention is determined by whether the cleaning solution of the present invention falls vertically or disperses in the cleaning solution (has a surface tension lowering effect). Table 7 shows the results.
[0048]
[Table 7]

The results in Table 7 also support that if the surface tension of the cleaning solution of the present invention can be reduced to 58 dyn / cm or less, it is possible to exhibit a certain re-contamination prevention ability.
[0049]
In addition, as the anti-redeposition component used in the present invention, not only those belonging to the category of the water-soluble polymer substance usually used as the anti-redeposition agent, but also in an amount not more than the critical micelle concentration in the cleaning liquid system of the present invention. It also includes the use of a surfactant having the above-mentioned predetermined surface tension lowering action.
[0050]
Next, in order to search the range of the anti-soil re-contamination component which can be used in the present invention, the standard amount is about 1/10 or less of the standard surfactant concentration (anionic type) in the existing synthetic detergent. Various re-soil preventing substances (equivalent to a concentration of 0.5 g of a re-soil preventing component added to 30 L of washing water and dissolved) so as to have a concentration of about 0.017 g / L in the washing liquid of the present invention (dispersant) Was sometimes added to the cleaning solution, and the re-contamination prevention performance at this time was evaluated. The component composition of the cleaning composition of the present invention is 28.6 g of the inorganic salt main ingredient + 0.5 g of each anti-redeposition substance, and the component composition of the inorganic salt main ingredient is 10 g of sodium carbonate + 7.8 g of sodium hydrogen carbonate + metasilicate. Sodium pentahydrate 10.8 g. Two types of cotton and polyester fiber were used as the clothing to be tested, and a certain amount of black ink was dropped as dirt, and the difference in whiteness before and after washing when washed in the cleaning solution to be tested was compared. In addition, this re-contamination prevention performance evaluation test is performed under conditions according to the re-contamination test conditions described later. Tables 8 to 10 show the results.
[0051]
[Table 8]

[0052]
[Table 9]

[0053]
[Table 10]

As a result, various anti-soil re-contamination substances have (a) the ability to lower the surface tension and the anti-hydrophobic re-contamination ability, and the substance alone and having a sufficient anti-soil recontamination effect at a low concentration; Having only one of the surface tension lowering ability or the hydrophobic anti-soil repelling ability, alone cannot be used as the anti-soil re-contamination component of the present invention, but in combination to complement each other, or One that can provide a practical recontamination prevention effect in combination with the above dispersant (a), (c) No effect can be obtained unless the concentration is approximately the same as that of a conventional synthetic detergent, or inorganic salt washing In the case of the agent system, the effect of preventing re-contamination was not obtained, and it was divided into three groups.
[0054]
As described above, the dispersants which can be used as the anti-redeposition component of the present invention are those belonging to the group (a), which can be used alone, and the group (b), which can be used in combination with others.
[0055]
(A) those belonging to the group include non-ionic water-soluble polymer substances such as methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxyethylmethylcellulose, partially saponified polyvinyl alcohol, polypropylene glycol, and polyoxyethylene polyoxypropylene block copolymer; Alternatively, a nonionic surfactant is used.
[0056]
On the other hand, those belonging to the group (b) include water-soluble polymer substances such as sodium polyacrylate, polyethylene glycol, hydroxyethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monolaurate. And non-ionic or amphoteric surfactants such as polyglycerin fatty acid esters, ethylene glycol, and betaine lauramidopropyl acetate.
[0057]
(A) Those belonging to the group have a function of lowering the surface tension of the cleaning liquid to about 58 dyn / cm or less in a small amount, and furthermore, have good adsorption and dispersibility to hydrophobic fibers and nonpolar stains. I can say. It should be noted that those having a good ability to prevent hydrophobic recontamination generally have good adsorbability and dispersibility to hydrophilic fibers and polar stains.
[0058]
(B) those belonging to the group include nonionic or amphoteric dispersants having surface tension lowering ability but weak dispersing ability, and anionic dispersants having dispersing ability but no surface tension lowering ability. It is relatively effective for hydrophilic fibers and polar stains, but has little effect on hydrophobic fibers and non-polar stains, and provides re-contamination prevention performance for both cotton and chemical fibers (polyester) with a small amount. Under such a premise, there is a tendency that it is difficult to obtain a sufficient re-contamination prevention performance by a member belonging to the group (b) alone.
[0059]
(A) Although the re-contamination prevention performance of the members belonging to the group improves as the concentration increases, it is preferable to use them in a concentration range that is practically necessary and as low as possible from the viewpoint of reducing environmental load. It should be noted that even if the concentration of these re-contamination preventing substances is increased, the decrease in surface tension is leveled off, and the concentration has almost no effect on the detergency.
[0060]
These are shown in the examples tested for polyvinyl alcohol (see Table 11).
[0061]
[Table 11]

Further, the effect of changing the parameter of the degree of polymerization on the re-staining effect of partially saponified polyvinyl alcohol is shown. (See Table 12).
[0062]
[Table 12]

According to Table 12, among the partially saponified polyvinyl alcohols (PVA), good results were obtained up to those having a degree of polymerization of about 1000.
[0063]
Further, in order to see the influence of the hydrophobic group, a test was carried out on Pluronics in which the respective molecular weight composition ratios of the hydrophilic group polyoxyethylene and the hydrophobic group polyoxypropylene can be variously changed, and the results shown in FIG. 2 were obtained.
[0064]
According to the evaluation results of the re-contamination prevention performance in FIG. 2, a good effect is exhibited when the size (molecular weight) of the hydrophobic group exceeds 3000. Although the overall molecular weight (total molecular weight) increases to the right and upward of the grid, it is considered that the size of the hydrophobic group is important because the smaller the hydrophobic group has little effect even if the total molecular weight is the same. When the size of the hydrophobic group is the same, the smaller the ratio of the hydrophilic group to the total molecular weight, the better the ability to prevent re-contamination of the hydrophobic fiber. In other words, if the size of the hydrophobic group is the same, it can be said that the smaller the total molecular weight is, the more advantageous the hydrophobic fiber is.
[0065]
From the above findings, water-soluble polymer substances that can be suitably used as the re-contamination-preventing component in the present invention are more preferably non-ionic, hydrophobic and large hydrophobic groups. It is a substance that satisfies the two conditions of having a part. Of these, substances that can be more preferably used are substances having an average molecular weight of about 1,000 to 500,000, relatively low molecular weight, more preferably about several thousand. Further, from the viewpoint of safety and biodegradability, cellulose-based, polyhydric alcohol-based, fatty acid-based and the like are preferable, and specifically, methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxyethylmethylcellulose, partially saponified polyvinyl alcohol, and the like. Is particularly preferred.
[0066]
In addition, there are hydrophilic fibers and hydrophobic fibers in clothing, and there is compatibility with such fibers in the anti-soil re-contamination component. More often, the combination of the above-mentioned substances in the group (a) or the combination of the substances in the group (a) and the substances in the group (b) is more effective. Most suitable are combinations of two or more of the above.
[0067]
Table 13 shows the results of evaluation of various combinations of components for preventing re-contamination.
[0068]
[Table 13]

From Table 13, it can be seen that, among the re-contamination preventing substances of the group (a), those which show relatively good results for cotton and those which show good results for polyester fiber are successfully combined with each other in a smaller amount. It can be seen that the re-contamination preventing effect can be exerted on the hydrophilic fibers and the hydrophobic fibers in a well-balanced manner. Among them, particularly good results were obtained with a 1: 1 combination of partially saponified polyvinyl alcohol and hydroxypropylmethylcellulose.
[0069]
In the cleaning composition of the present invention, the total amount of the anti-redeposition component is preferably 10% by weight or less of the total amount of the cleaning composition.
[0070]
Further, provided that the anti-redeposition performance reaches a practical level, it is more preferable that the total amount of the anti-redeposition component is 9% by weight or less of the total amount of the detergent composition. Washing in the following order: 1 wt% or less, 7 wt% or less, 6 wt% or less, 5 wt% or less, 4 wt% or less, 3 wt% or less, 2 wt% or less, 1 wt% or less. It is desirable that the amount of the anti-redeposition component in the agent composition is as small as possible.
[0071]
In the present invention, the component for preventing re-contamination such as a water-soluble polymer plays an important role but is an organic substance, and the smaller the amount of such an organic substance is, the better the purpose of the present invention is to reduce the environmental load.
[0072]
In addition, the concentration of the anti-redeposition component in the cleaning solution obtained by dissolving the inorganic cleaning composition of the present invention in water to 1 g / L assuming standard use is at least 0.007 g / L (0. 0007% by weight, equivalent to the component concentration when 0.2 g of the re-contamination preventing component is dissolved in 30 L of washing water), and preferably 0.01 g / L (0.001% by weight, 30 L of washing water). (Corresponding to the component concentration when 0.3 g of the pollution control component is dissolved). When the blending ratio of the inorganic salt in the detergent composition of the present invention is 90% by weight, the upper limit of the blending ratio of the anti-redeposition component in the composition is 10% by weight. The upper limit of the concentration of the anti-redeposition component in the medium is 0.1 g / L (corresponding to the component concentration when 3 g of the anti-redeposition component is dissolved in 0.01 L of 30 L of washing water).
[0073]
Further, as described above, the alkali metal silicate, which is one of the main components of the inorganic salt cleaning agent of the present invention, is not as effective as the re-contamination preventing substance belonging to the group (a), but has a re-contamination preventing effect. Can be used together, and by using them together, it is possible to reduce the amount of the organic recontamination preventing substance belonging to the group (a).
[0074]
The improvement of the re-contamination prevention performance when a silicate or an organic re-contamination preventing substance was added to the inorganic salt main agent related to the combination of bicarbonate and carbonate was confirmed. The sodium metasilicate was replaced with the same weight ratio as the sodium carbonate in the main agent, and the ability to prevent re-contamination when the blending ratio was gradually increased was evaluated. Note that the amount of the organic re-contamination preventing substance was fixed.
[0075]
[Table 14]

From these results, it is preferable that sodium metasilicate (as pentahydrate) accounts for 30 to 70% by weight of the total amount of the detergent.
[0076]
As described above, by using the water-soluble silicate and the anti-redeposition substance belonging to the group (a) together, the lower limit concentration of the organic anti-redeposition component contained in the cleaning solution is 0.007 g / L (0.0007% by weight). ) To a practically recontamination-preventing effect at very low concentrations. This corresponds to an amount of organic matter used which is 1/10 or less of that of a conventional synthetic detergent or the like.
(3)Additive
The cleaning agent of the present invention is a component commonly used in synthetic detergents such as a washing enzyme, an oxygen bleach, a bactericide, a fragrance, a water softener, and a foaming agent, as necessary, without departing from the spirit of the present invention. May be further included.
[0077]
The most important of these additives are laundry enzymes. The cleaning system of the present invention containing an alkaline inorganic salt base and a re-contamination-preventing component is useful for removing dirt that cannot be completely removed. Laundry enzymes include proteolytic enzymes (proteases), lipolytic enzymes (lipases), cellulolytic enzymes (cellulases), and amylolytic enzymes (amylases). Among them, proteases are particularly effective against daily soiling. Cellulase is effective in maintaining whiteness of cotton fibers and removing solid particle stains when repeatedly washed, and is highly practical.
[0078]
The amount of the enzyme may be about 0.3% to 3% by weight per enzyme based on the total amount of the detergent composition.
[0079]
In addition, since the liquidity of the present detergent is weakly alkaline, it is necessary to select a detergent that does not decrease the activity value in the pH range when studying the formulation of the enzyme. Conversely, the pH range is preferably set not only in consideration of the detergency by the alkali salt, but also in consideration of the fact that the activity of the enzyme incorporated in the composition is sufficiently exhibited. .
[0080]
It should be noted that a particular point to be noted in blending the enzyme with the detergent is the stability of the enzyme activity in the washing solution, and in particular, attention must be paid to the deactivation by the effective free chlorine contained in the washing water. The cleaning agent of the present invention contains carbonate as one of the main components. However, since the carbonate has an effect of accelerating the oxidation reaction by effective free chlorine, special care must be taken.
[0081]
Therefore, it is necessary to add the enzyme and the reducing agent at the same time in the formulation into the detergent. Sulfites and thiosulfates are suitable as reducing agents, but there is also a method using an ammonium salt such as ammonium sulfate to trap active chlorine and prevent inactivation of the enzyme. The amount of these components is preferably about 0.3% to 3% by weight based on the total amount of the detergent composition.
[0082]
Examples of the oxygen-based bleach include sodium percarbonate, sodium perborate, hydrogen peroxide and the like. The cleaning composition of the present invention exhibits the same detergency as a conventional synthetic detergent based on a surfactant without using an oxygen bleaching agent, but further improves the cleaning performance by adding a bleaching agent. Can be expected.
[0083]
The disinfectant is formulated for the purpose of preventing decay and mold of the detergent composition containing organic substances in addition to disinfecting the object to be washed, and according to the intended use among benzalkonium chloride, paraben, propylene glycol and the like. Can be selected appropriately. Considering the safety to the human body, it is desirable to add an extract extracted from citrus fruit seeds. Here, citrus fruit is a grapefruit whose scientific name is Citrus paradesi, and since the extract itself is highly viscous, it is diluted with water when added, and natural glycerin, propylene glycol, etc. It is preferable to use a dispersant. Since the extract of the seeds of Citrus paradesi has a bacteriostatic effect such as sterilization of bacteria and microorganisms and antibacterial activity, when added as a bacteriostatic additive to the detergent composition of the present invention, the bacteriostatic effect of the material to be washed is reduced. Can be expected. As other fungicides, natural fungicides obtained from tea leaves, bamboo, etc. may be blended.
(4)Method for producing cleaning composition
Since almost all the raw materials of the detergent composition of the present invention are powders or granules, and they need only be uniformly mixed, they can be easily produced into various dosage forms by various methods. The simplest and most economical production method is to produce the powdered or granular cleaning composition of the present invention simply by stirring and mixing these powder materials with a known batch-type mixer.
[0084]
It can be made into a tablet type or a sheet type for each use amount for ease of use. Further, the detergent composition of the present invention can be manufactured as a concentrated liquid type detergent by mixing a powder raw material and water.
[0085]
In the case where the weak alkaline inorganic salt washing liquid of the present invention is produced by electrolyzing a sodium hydrogen carbonate aqueous solution stored in the washing tub, for example, in a circulating manner or in a batch manner, the silicate or the water-soluble A re-contamination preventing component containing a polymer substance may be separately added in the form of a powder or an aqueous solution.
(5)Cleaning solution
The present invention basically relates to a garment to be washed with a washing liquid substantially free of a surfactant, comprising an inorganic salt washing action component forming an alkaline buffer system as a main washing action component, and a re-staining preventive component. A washing method. Further, if a washing enzyme further contains a washing enzyme, washing performance can be further improved.
[0086]
As described above, it is a preferred embodiment that the alkaline inorganic salt in the present invention contains an alkali metal bicarbonate and an alkali metal carbonate and / or an alkali metal silicate as main components. In the cleaning solution of the present invention, it is preferable that the washing solution is dissolved at a concentration of about 1 to 2 g / L (0.1 to 0.2% by weight) as a total amount of alkaline inorganic salts. The alkali metal bicarbonate and the alkali metal carbonate are preferably present in a molar ratio of 1: 7 to 1: 0.2. , In a molar ratio of 1: 1.2 to 1: 0.1. When these are present in a three-component system, the alkali metal silicate can be arbitrarily replaced with the alkali metal carbonate from the viewpoint of detergency. The silicate is preferably pentahydrate of sodium metasilicate from the viewpoints of pH, solubility, reduction of the total amount used and production cost.
[0087]
The pH of the washing solution (1 g / L concentration) of the present invention mainly determined by the alkaline inorganic salt buffer system is preferably from 9.5 to 11, and more preferably from 10 to 10.6 from the viewpoints of detergency, water softening rate and the like.
[0088]
Further, the total amount of the (organic) re-contamination preventing component, which is one important component in the inorganic cleaning liquid of the present invention, is preferably 0.01 g / L (0.001% by weight) or more. When sodium metasilicate (pentahydrate), which also has re-contamination prevention performance, is used in an amount of 30 to 70% by weight based on the total amount of the cleaning composition, the concentration of the organic re-contamination prevention component contained in the cleaning liquid is 0.007 g / L. (0.0007% by weight) or more.
[0089]
Under general washing conditions such as low temperature washing with low hardness water as in Japan, the actual use concentration of the washing liquid according to the present invention is 0.5 to 5 g / L (0.05 to 0.5% by weight). Within the range. The actual use concentration in such a range corresponds to the actual use concentration in the claims, and is 0.5 g / L (0.05% by weight, the concentration when 15 g of the detergent composition is dissolved in 30 L of washing water). The use concentration diluted to about the level is used when washing lightly soiled clothing, and the concentration when 150 g of the detergent composition is dissolved in 5 g / L (0.5% by weight, 30 L of washing water). The use concentration increased up to about) is used, for example, when washing in a soak-in-wash or in a high-hardness washing water area, and in an intermediate concentration range between the low concentration and the high concentration, the amount of clothing to be washed is An appropriate concentration is used depending on the washing water capacity and the like. In such a practical use concentration range, the detergent of the present invention exhibits a washing performance almost equal to or higher than that of existing laundry soaps and synthetic detergents.
[0090]
Hereinafter, the relationship between the input amount and the pH of the cleaning liquid for the powder cleaning composition having the standard composition of the present invention will be described.
[0091]
Using a detergent composition containing 112 g of sodium carbonate, 60 g of sodium bicarbonate, 110 g of sodium metasilicate pentahydrate, and 18 g of other additives to make the total weight of the detergent 300 g, 30 liters of water was used. The pH value (25 ° C.) of each washing solution at each concentration in the range of 0.5 to 5 g / L (0.05 to 0.5% by weight) when dissolved in water is as follows. . That is, 10.39% at 0.05% by weight (the input amount of the powder detergent composition is 15g / 30L), 10.64% and 0.15% by weight at the 0.10% by weight (the input amount is 30g). The input amount was 10.73 at 45 g / 30 L), 10.78 at 0.20 wt% (the input amount was 60 g / 30 L), and 10.79 at 0.25 wt% (the input amount was 75 g / 30 L). It is 10.80 at 0.30% by weight (the same input amount is 90 g / 30L) and 10.89 at 0.50% by weight (the same input amount is 150g / 30L).
[0092]
Function and effect of the present invention
According to the present invention, there is provided a detergent composition which does not use a surfactant which is questionable from the viewpoint of safety to the human body and reduction of environmental load, or in which the amount of the surfactant is significantly reduced. It is possible to provide a detergent composition containing an inorganic salt as a main component, which has a detergency and ease of use equivalent to or higher than that of a detergent containing an enzyme or a bleaching agent, and is particularly excellent in recontamination prevention performance. Further, according to the method for washing clothes, the detergent composition for clothes, and the re-staining agent according to the present invention, a seeming contradiction between cleanliness that dislikes dirty and health-oriented dislikes residual detergent components in clothes. Modern Japanese consumers' needs can be met at an extremely high level.
[0093]
When the alkali metal bicarbonate and the carbonate and / or silicate are dissolved in water and set to a specific pH and concentration range, a washing effect by saponification and decomposition of grease stains and the like by the alkali agent can be obtained. In addition, since the buffer system coexists with bicarbonate, a large amount of carbonate and / or silicate alkaline action salt can be added, and the ionic strength of the washing solution is increased. When the anions are adsorbed to both sides, an electric repulsion acts and solid dirt is easily separated from the surface of the laundry. Furthermore, the hardness component, which is a deterrent to the detergency in conventional washing systems, such as calcium ions and magnesium ions contained in water, becomes carbonate, and colloidal calcium carbonate generated during the generation or coagulation of the carbonate is used as a cleaning solution. It adsorbs dirt particles inside and improves the cleaning performance.
[0094]
Silicates, especially sodium metasilicate, form colloids in an aqueous solution and essentially have an effect of adsorbing inorganic dirt particles or dispersing them in a cleaning solution, and thus adsorbing dirt particles to fibers, that is, re-contamination. It also has the effect of preventing. When a detergent composition based on carbonate and bicarbonate is combined with a silicate, it can be replaced with carbonate in any proportion without compromising detergency.
[0095]
A detergent composition in which such a main cleaning action is obtained by an inorganic salt has a surface tension lowering action of methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxyethylmethylcellulose, partially saponified polyvinyl alcohol and the like and an ability to prevent recontamination of hydrophobic fibers. By adding a very small amount of a water-soluble polymer substance having a high concentration, the re-contamination prevention performance, which was the main factor that hindered the spread of alkaline inorganic salt detergents, was greatly improved, and its washing performance was as good as that of synthetic detergents. It can be at a practical level. The water-soluble polymer substance having an effect of lowering the surface tension is particularly effective for chemical fibers such as polyester which is easily re-contaminated and difficult to prevent the re-contamination, and other re-contamination including the above-mentioned sodium metasilicate. By using the anti-redeposition component together with the anti-redeposition component, the amount of the whole anti-redeposition component can be further reduced.
[0096]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, specific examples in which the cleaning composition or the cleaning liquid of the present invention is compared with a conventional cleaning composition and its cleaning liquid will be described. However, the specific numerical values shown below exemplifyly disclose a part of the washing performance obtained by using the cleaning composition of the present invention, and are not intended to limit the present invention. In the examples or comparative examples related to the detergency test disclosed herein, the detergency may change according to the difference between the lot numbers of the contaminated cloths used. Note that it may not be possible to simply compare the values between different tests.
Detergency test 1
Prior to the description of the detergency test No. 1, the test conditions will be clarified.
[0097]
Detergency test conditions
The washing machine is a fully automatic washing machine manufactured by Toshiba Corporation (AW-C60VP, 6 kg type, water level setting 31 liters, towel 2 kg as load), tap water at a water temperature of 20 ° C. (Fujisawa city tap water, pH 7.5, (EC 19 mS / m), washing for 12 minutes, rinsing once, and dehydration for 5 minutes.
[0098]
In this washing machine, three artificially stained cloths (manufactured by Scientific Services S / D Inc. USA, two types of cotton and mixed spinning) to which "artificial sebum" is attached, and a stained cloth (EMPA101) to which mineral oil and carbon black are attached, Contaminated cloth with olive oil and carbon black (EMPA106), contaminated cloth with blood (EMPA111), contaminated cloth with cacao, a protein (EMPA112), contaminated cloth with red wine (EMPA114), blood and milk Each of three pieces of contaminated cloth (EMPA116) to which carbon black was attached was sewn to a towel and washed. The “cleaning rate” was calculated by the following equation.
[0099]
Cleaning rate% = (whiteness of stained cloth after washing−whiteness of stained cloth before washing) ÷ (whiteness of unstained cloth−whiteness of stained cloth before washing) × 100
Here, the "whiteness" was obtained by averaging the measured values of ten different front and back points of each of the three contaminated cloths using a whiteness meter (CR-14, Whiteness Index Color Reader manufactured by Minolta Co., Ltd.).
[0100]
It should be added that the detergency test disclosed in this specification is performed in accordance with the test conditions unless otherwise specified.
[0101]
Example 1
In 31 liters of tap water, each component composition is composed of 9 g of sodium carbonate, 10 g of sodium hydrogen carbonate, 22 g of sodium metasilicate (9-hydrate), 0.2 g of methylcellulose, and 0.2 g of polyvinyl alcohol, and the total amount of the components is 41.4 g. Was dissolved to obtain a cleaning solution having a detergent concentration of 1.34 g / L and a pH of 10.6. The washing rate of each contaminated cloth before and after washing when washing with this washing liquid was measured. Table 15 shows the results.
[0102]
Example 2
To 31 liters of tap water, a detergent consisting of 16 g of sodium hydrogen carbonate, 40 g of sodium metasilicate (9-hydrate), 0.2 g of methylcellulose, and 0.2 g of polyvinyl alcohol was used, and the total amount of the same components was 56.4 g. After dissolution, a detergent solution having a detergent concentration of 1.82 g / L and a pH of 10.6 was obtained. The washing rate of each contaminated cloth before and after washing when washing with this washing liquid was measured. Table 15 shows the results.
[0103]
Example 3
In 31 liters of tap water, a detergent consisting of 18 g of sodium carbonate, 8 g of sodium bicarbonate, 0.2 g of methylcellulose, and 0.2 g of polyvinyl alcohol is dissolved, and the total amount of the components is 26.4 g. Was 0.85 g / L and pH was 10.3. The washing rate of each contaminated cloth before and after washing when washing with this washing liquid was measured. Table 15 shows the results.
[0104]
Example 4
In the same manner as in Example 1 except that the components of 0.3 g of protease as an enzyme, 0.1 g of cellulase, and 0.6 g of sodium sulfite as a reducing agent were further added to and dissolved in the washing solution of Example 1, respectively. Then, the cleaning rate of the contaminated cloth was measured. Table 15 shows the results.
[0105]
Example 5
Further, 0.3 g of protease as an enzyme, 0.1 g of cellulase, 0.6 g of sodium sulfite as a reducing agent, and 6 g of sodium percarbonate as a bleaching agent were added to the washing solution of Example 1 and dissolved. The cleaning rate of the contaminated cloth was measured in the same manner as in Example 1 except that the cleaning was performed. Table 15 shows the results.
[0106]
Comparative Example 1
As a comparative example of Examples 1 to 5, a detergent consisting of 18 g of sodium carbonate and 8 g of sodium hydrogencarbonate in 31 liters of tap water and having a total amount of the same component of 26 g was dissolved, and the concentration of the detergent was 0.1 g. A cleaning solution having a pH of 10.4 was obtained at 84 g / L. Using this cleaning liquid, the cleaning rate of the contaminated cloth was measured in the same manner as in Example 1. Table 15 shows the results.
[0107]
Comparative Example 2
As a comparative example of Examples 1 to 5, a cleaning solution (a detergent concentration of 1 g / L, manufactured by Miyoshi Soap Manufacturing Co., Ltd.) obtained by dissolving a commercially available powdered soap in tap water at a standard concentration was used. Similarly, the cleaning rate of the contaminated cloth was measured. Table 15 shows the results.
[0108]
Comparative Example 3
As a comparative example of Examples 1 to 5, a cleaning solution prepared by diluting and dissolving a commercially available liquid synthetic detergent in tap water at a standard concentration (liquid attack, detergent concentration 20 mL / 31 L, manufactured by Kao Corporation, without blending of enzyme and bleaching agent) ), The cleaning rate of the contaminated cloth was measured in the same manner as in Example 1. Table 15 shows the results.
[0109]
Comparative Example 4
As a comparative example of Examples 1 to 5, a washing solution prepared by dissolving a commercially available powdered synthetic detergent at a standard concentration in tap water (new beads, detergent concentration 0.8 g / L, manufactured by Kao Corporation, containing enzyme and bleach) , And the cleaning rate of the contaminated cloth was measured in the same manner as in Example 1. Table 15 shows the results.
[0110]
Comparative Example 5
As a comparative example of Examples 1 to 5, using a washing solution (attack, 0.65 g / L, manufactured by Kao Corporation, containing enzyme and bleach) prepared by dissolving a commercially available powdered synthetic detergent in tap water at a standard concentration, The cleaning rate of the contaminated cloth was measured in the same manner as in Example 1. Table 15 shows the results.
[0111]
[Table 15]

As is clear from the comparison between the cleaning rates of Examples 1 to 5 and Comparative Examples 2 to 5, the cleaning liquids containing the inorganic salt of the present example as a washing agent and a re-staining preventive component were all commercially available interface liquids. It shows almost the same or better detergency as laundry soap or synthetic detergent using an activator as a laundry agent. When Examples 4 to 5 and Comparative Examples 2 to 5 are compared, those of Examples 4 and 5 to which an enzyme, a reducing agent and a bleaching agent are further added are equivalent to the conventional laundry soap or synthetic detergent. It can be understood that the detergency shows a detergency higher than that, and is particularly excellent in detergency for protein stains.
[0112]
In addition, comparing Examples 1 to 3 with Comparative Example 1, the water-soluble polymer substances having a surface tension lowering effect, such as methylcellulose and polyvinyl alcohol, added in the examples were washed in the first test of the washing. The rate has little effect.
[0113]
Furthermore, when Examples 1 and 2 and Example 3 are compared, it can be understood that even if sodium metasilicate and sodium carbonate are replaced, the cleaning rates are almost the same.
Recontamination test 1
The recontamination test No. 1 was performed under the following test conditions, and the effect of preventing recontamination was confirmed.
[0114]
Recontamination test conditions
The washing machine used was a two-tub washing machine manufactured by Sharp Corporation (ES-25E, water level setting: 30 liters, load: 1.5 kg of towel), tap water at a water temperature of 20 ° C. (Fujisawa City tap water, pH 7.2, (EC 15.5 mS / m), washing for 10 minutes, rinsing with running water for 4 minutes, and dehydration for 5 minutes.
[0115]
0.45 g of black ink as a pseudo soil of recontamination was dropped into this washing machine, and three cotton and polyester white cloths (5 cm square) were sewn on a towel and washed with the following contaminated cloths.
[0116]
The recontamination evaluation was performed by measuring the whiteness before and after washing each of the three cotton and polyester white cloths (5 cm square). The recontamination degree as an evaluation value was a value obtained by subtracting the whiteness before washing from the whiteness after washing. When the recontamination degree is positive, it means that the whiteness is higher after cleaning, and when the recontamination degree is negative, it means that the whiteness is reduced due to recontamination after cleaning. Therefore, if the degree of re-contamination is zero or a positive value (however, -1 or more in the case of polyester), it can be determined that the re-contamination prevention performance has no practical problem.
[0117]
It should be added that the recontamination test disclosed in this specification is performed under the test conditions unless otherwise specified.
[0118]
Example 6
Washing was performed using the cleaning liquid obtained in Example 1, and the degree of recontamination at this time was calculated. Table 16 shows the results.
[0119]
Example 7
Using the cleaning solution obtained in Example 2, recontamination was evaluated under the same conditions as in Example 6. Table 16 shows the results.
[0120]
Example 8
Using the cleaning solution obtained in Example 3, recontamination was evaluated under the same conditions as in Example 6. Table 16 shows the results.
[0121]
Comparative Example 6
As a comparative example of Examples 6 to 8, recontamination was evaluated under the same conditions as in Example 6 using the cleaning solution obtained in Comparative Example 1. Table 16 shows the results.
[0122]
Comparative Example 7
As a comparative example of Examples 6 to 8, a detergent comprising 31 g of tap water, 9 g of sodium carbonate, 10 g of sodium hydrogen carbonate, and 22 g of sodium metasilicate (9-hydrate) in a total amount of 41 g was used. Was dissolved to obtain a cleaning solution having a detergent concentration of 1.32 g / L and a pH of 10.6. Using this cleaning solution, recontamination was evaluated under the same conditions as in Example 6. Table 16 shows the results.
[0123]
Comparative Example 8
As a comparative example of Examples 6 to 8, recontamination was evaluated using the cleaning solution of Comparative Example 3 under the same conditions as in Example 6. Table 16 shows the results.
[0124]
[Table 16]

As is clear from these results, the recontamination degree is large and cannot be put to practical use unless the water-soluble polymer substance is added (see Comparative Examples 6 and 7), but Examples 6 to 8 in which the water-soluble polymer substance is added are used. The cleaning liquid having the lowest recontamination prevention effect (Example 8) exhibits the recontamination prevention performance of Comparative Examples 6 and 7 or more.
[0125]
Comparing Examples 6 to 8, it can be understood that the greater the content of sodium metasilicate in the cleaning agent, the higher the re-contamination prevention performance.
Recontamination test 2
Example 9
In 31 liters of tap water, a detergent consisting of 9 g of sodium carbonate, 10 g of sodium hydrogen carbonate, 22 g of sodium metasilicate (9-hydrate), and 0.4 g of methylcellulose, each having a total amount of 41.4 g, is dissolved. Thus, a cleaning solution having a detergent concentration of 1.34 g / L and a pH of 10.6 was obtained. Using this cleaning solution, recontamination was evaluated under the same conditions as in Example 6. Table 17 shows the results.
[0126]
Example 10
Dissolves a detergent consisting of 9 g of sodium carbonate, 10 g of sodium hydrogen carbonate, 22 g of sodium metasilicate (9-hydrate) and 0.4 g of polyvinyl alcohol in 31 liters of tap water, the total amount of which is 41.4 g. Thus, a cleaning solution having a detergent concentration of 1.34 g / L and a pH of 10.6 was obtained. Using this cleaning solution, recontamination was evaluated under the same conditions as in Example 6. Table 17 shows the results.
[0127]
Example 11
To 31 liters of tap water, a detergent consisting of 9 g of sodium carbonate, 10 g of sodium hydrogen carbonate, 22 g of sodium metasilicate (9-hydrate), and 0.4 g of hydroxypropylcellulose with a total amount of 41.4 g of the same component was used. Upon dissolution, a cleaning solution having a detergent concentration of 1.34 g / L and a pH of 10.7 was obtained. Using this cleaning solution, recontamination was evaluated under the same conditions as in Example 6. Table 17 shows the results.
[0128]
Example 12
In 31 liters of tap water, each component composition is composed of 9 g of sodium carbonate, 10 g of sodium hydrogen carbonate, 22 g of sodium metasilicate (9-hydrate), 0.2 g of hydroxypropylcellulose, and 0.2 g of polyethylene glycol. After dissolving 0.6 g of the detergent, a detergent having a detergent concentration of 1.34 g / L and a pH of 10.7 was obtained. Using this cleaning solution, recontamination was evaluated under the same conditions as in Example 6. Table 17 shows the results.
[0129]
Example 13
In 31 liters of tap water, each component composition is composed of 9 g of sodium carbonate, 10 g of sodium hydrogen carbonate, 22 g of sodium metasilicate (9-hydrate), 0.45 g of LT, and 0.15 g of carboxymethyl cellulose, and the total amount of the components is 41.6 g. The detergent was dissolved to obtain a detergent having a detergent concentration of 1.34 g / L and a pH of 10.6. Using this cleaning solution, recontamination was evaluated under the same conditions as in Example 6. Table 17 shows the results.
[0130]
Comparative Example 9
As a comparative example of Examples 9 to 13, a detergent comprising 31 g of tap water, 9 g of sodium carbonate, 10 g of sodium hydrogen carbonate, and 22 g of sodium metasilicate (9-hydrate), each having a total amount of 41 g. Was dissolved to obtain a cleaning solution having a detergent concentration of 1.32 g / L and a pH of 10.6. Using this cleaning solution, recontamination was evaluated under the same conditions as in Example 6. Table 17 shows the results.
[0131]
[Table 17]

As is clear from the results of the recontamination test No. 2 in which the combination ratio and amount of the inorganic salt main component composition were fixed and the type and amount of the anticontamination agent were compared in various combinations, the water-soluble polymer substance was used alone. In the case of adding, the polyvinyl alcohol (see Example 10) exhibits the best resoil prevention performance in consideration of the balance between cotton and chemical fibers (polyester).
Detergency test 2
The detergency test No. 2 was performed under test conditions in accordance with the detergency test No. 1, and the cleaning performance was compared with the existing synthetic detergent and laundry soap.
[0132]
Example 14
In 31 liters of tap water, 30 g of the cleaning agent A (containing no enzyme) of the present invention having the following components was dissolved in 30 L of washing water, and the laundry was washed with a washing liquid obtained. The cleaning rate of the cloth was measured. Table 18 shows the results.

Example 15
In 31 liters of tap water, 30 g of the detergent B (containing enzyme) of the present invention composed of the following components was dissolved in 30 L of water for washing, and each of the contaminated cloths before and after washing was washed with a washing liquid obtained. Was measured. Table 18 shows the results.

Comparative Example 10
As a comparative example of Examples 14 and 15, contamination was carried out in the same manner as in Example 14 using a cleaning solution (detergent concentration: 20 mL / 31 L, blended with enzyme) prepared by diluting and dissolving a commercially available liquid synthetic detergent in tap water at a standard concentration. The cleaning rate of the cloth was measured. Table 18 shows the results.
[0133]
Comparative Example 11
As a comparative example of Examples 14 to 15, the same as Example 14 using a washing solution (0.65 g / L, containing an enzyme and a fluorescent whitening agent) in which a commercially available powdered synthetic detergent was dissolved in tap water at a standard concentration. Then, the cleaning rate of the contaminated cloth was measured. Table 18 shows the results.
[0134]
Comparative Example 12
As a comparative example of Examples 14 to 15, a contaminated cloth was prepared in the same manner as in Example 14 using a cleaning liquid (for atopic patients, 9% surfactant mixture) in which a commercially available liquid detergent was dissolved in tap water at a standard concentration. Was measured. Table 18 shows the results.
[0135]
Comparative Example 13
As a comparative example of Examples 14 to 15, the cleaning rate of a contaminated cloth was determined in the same manner as in Example 14 using a cleaning liquid (cleaning liquid concentration: 1 g / L) obtained by dissolving commercially available powdered pure soap in tap water. It was measured. Table 18 shows the results.
[0136]
Table 18 shows the results of performing the detergency test on Examples 14 and 15 and Comparative Examples 10 to 13.
[0137]
[Table 18]

As is clear from the comparison between the cleaning rates of Examples 14 and 15 and the cleaning rates of Comparative Examples 10 and 13, the cleaning liquids containing the inorganic salt of the present example as a washing agent and a re-staining prevention component were all commercially available. It shows a detergency almost equal to or higher than that of a laundry soap or a synthetic detergent using a surfactant as a laundry agent. Among these, when comparing Examples 14 to 15 and Comparative Examples 10 to 13, those of Example 15 to which an enzyme and a reducing agent are further added are generally equivalent to or better than conventional washing soaps or synthetic detergents. It shows that the performance is excellent, and the cleaning power is excellent especially for protein stains.
Recontamination test 3
The recontamination test No. 3 was performed under the test conditions according to the recontamination test No. 1, and the recontamination prevention performance was compared and confirmed with the existing synthetic detergent and laundry soap.
[0138]
Example 16
In 31 liters of tap water, 30 g of the cleaning agent A of the present invention (containing no enzyme) having the same component composition as in Example 14 was dissolved in 30 L of washing water, and washed with a washing liquid obtained. Was determined by calculation. Table 19 shows the results.
[0139]
Example 17
In 31 liters of tap water, 30 g of the cleaning agent B (containing enzyme) of the present invention having the same component composition as in Example 15 was dissolved in 30 L of washing water, and was washed using a cleaning liquid. The degree of recontamination was calculated. Table 19 shows the results.
[0140]
Comparative Example 14
As a comparative example of Examples 16 to 17, washing was performed using the same cleaning liquid as in Comparative Example 10, and the degree of recontamination at this time was calculated. Table 19 shows the results.
[0141]
Comparative Example 15
As a comparative example of Examples 16 to 17, washing was performed using the same cleaning liquid as in Comparative Example 11, and the recontamination degree at this time was calculated. Table 19 shows the results.
[0142]
Comparative Example 16
As a comparative example of Examples 14 and 15, washing was performed using the same cleaning liquid as in Comparative Example 12, and the degree of recontamination at this time was determined by calculation. Table 19 shows the results.
[0143]
Comparative Example 17
As a comparative example of Examples 14 and 15, washing was performed using the same cleaning liquid as in Comparative Example 13, and the degree of recontamination at this time was determined by calculation. Table 19 shows the results.
[0144]
[Table 19]

PVA (PVA) selected on the basis of knowledge obtained by conducting a performance evaluation test assuming use in combination with the inorganic salt detergent of the present invention and assuming the use of various recontamination preventing substances alone or in combination. The cleaning liquid of the present invention containing the anti-soil refining agent according to the combination of (polyvinyl alcohol) and HPMC (hydroxypropyl methyl cellulose) correlates with the presence or absence of the enzyme, as is clear from the result of the re-staining test No. 3. It can be seen that both the cotton and the chemical fiber (polyester) exhibited substantially the same or higher re-contamination prevention performance as a laundry soap or a synthetic detergent using a commercially available surfactant as a laundry agent.
COD / BOD analysis test
A washing solution obtained by dissolving the detergent of the present invention in water at a practical concentration of 1 g / L (0.1% by weight), and a washing solution obtained by dissolving a commercially available powdered synthetic detergent in water at a standard concentration. , Are shown in Table 20. In addition, this analysis test was performed in accordance with JIS “Factory drainage test method”.
[0145]
[Table 20]

From the analysis test results in Table 20, the cleaning liquid obtained from the cleaning agent of the present invention is approximately 1/20 in both COD and BOD as compared with the cleaning liquid obtained from a commercially available powdered synthetic detergent. It can be seen that if the detergent of the present invention is used in place of laundry for washing clothes, the environmental load can be significantly reduced.
Fish toxicity test
Using medaka as an aquatic creature, as a breeding water for the medaka, a washing solution (standard concentration: 0.7 g / L (0.07% by weight)) obtained by dissolving a commercially available powdered synthetic detergent in water; A cleaning solution obtained by dissolving soap in water (standard concentration: 1 g / L (0.1% by weight)) and a cleaning solution obtained by dissolving the cleaning agent of the present invention in water (standard concentration: 1 g / L (0% by weight)). .1% by weight)) was prepared for each washing solution as standard, five-fold dilution, and twenty-five-fold dilution, and 10 chicks were bred in each washing solution at a rate of one per liter. Table 21 shows the results of the fish toxicity test in which the change over time in the survival rate was observed.
[0146]
[Table 21]

From the results of the fish toxicity test in Table 21, it can be said that the cleaning solution of the present invention has extremely high safety against aquatic organisms as compared with a cleaning solution obtained from a commercially available powdered synthetic detergent or powdered pure soap.
Identification of drugs used
The following drugs were used for the drugs disclosed in the present specification.
Sodium carbonate: Soda Ash Co., Ltd. Tokuyama
Sodium bicarbonate: Sodium bicarbonate @ Tosoh Corporation
Sodium metasilicate: sodium metasilicate pentahydrate Na₂O 28-30%, SiO₂{27-29%} Nippon Chemical Co., Ltd.
Sodium sulfite: anhydrous sodium sulfite 亜 Daito Chemical Co., Ltd.
Methylcellulose: Metro's SM MC400 Shin-Etsu Chemical Co., Ltd.
Hydroxypropylcellulose: HPC {M-type} Tokuyama Corporation
Hydroxypropyl methylcellulose: Metroose SH {SEB-04T} Shin-Etsu Chemical Co., Ltd.
Hydroxyethyl methylcellulose: Metrose SE SNB-30T Shin-Etsu Chemical Co., Ltd.
Polyvinyl alcohol: Poval PA-05S Shin-Etsu Chemical Co., Ltd.
Degree of polymerization 3500 partially saponified type
Degree of polymerization 1000 partially saponified
Degree of polymerization 500 Partially saponified type Wako Pure Chemical Industries, Ltd. Reagent
Polypropylene glycol:
Triol (molecular weight 4000) Wako Pure Chemical Industries, Ltd.
Diol (Molecular weight 3000) Wako Pure Chemical Industries, Ltd.
Pluronic: Adeka Pluronic (L31, L34, L61, L64, F68, L101, P103, F108) １０８Asahi Denka Kogyo Co., Ltd.
Enzyme 1: Protease {Properase 1000E} Nagase ChemteX Corporation
Enzyme 2: Cellulase {celluzzyme 0.7T} Novozymes Japan KK
Surfactant:
Nonion (OT-221, LT-221) Nippon Oil & Fats Co., Ltd.
Betaine lauryl amide propyl acetate {PB-30L} Asahi Denka Kogyo Co., Ltd.
Polyglycerin fatty acid ester {CPG-150} Asahi Denka Kogyo Co., Ltd.
Polyethylene glycol oleate OEG-106 Asahi Denka Kogyo Co., Ltd.

[0147]
[Industrial applicability]
The cleaning composition of the present invention is a cleaning composition containing an alkaline inorganic salt as a main cleaning agent and substantially not using a surfactant, and is a laundry soap or a synthetic agent mainly containing a conventional surfactant. It has the same or higher detergency and ease of use as a detergent.
[0148]
There are many types of the present invention described above that clearly belong to the scope of identity. Such variations are not considered to be a departure from the spirit and scope of the invention, and all such modifications that are obvious to those skilled in the art are included within the technical scope of the claims according to the present invention. .
[Brief description of the drawings]
FIG. 1 is a diagram showing a change in cleaning rate when a concentration parameter of a cleaning liquid according to the present invention is changed.
FIG. 2 is a diagram showing the results of evaluating the performance of preventing re-contamination by Pluronics.

Claims (2)

A method for washing clothes, comprising using an inorganic salt forming an alkaline buffer system as a main washing component and washing with a washing solution containing at least a re-staining component. A detergent composition for clothing containing an inorganic salt forming an alkaline buffer system as a main cleaning component and further containing at least a component for preventing re-contamination.

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