JP3938536B2 - Package - Google Patents

Description

【００１７】
上記式（IV）において、Ｒ^１で表される炭素数１〜３のアルキル基としては、メチル基、エチル基、プロピル基、イソプロピル基などを挙げることができ、また、Ｒ^２で表される炭素数１〜５のアルキル基としては、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、ｔ−ブチル基、ペンチル基、イソペンチル基などを挙げることができる。
上記式（IV）で示される単量体の具体例として、Ｎ−ビニルホルムアミド、Ｎ−メチル−Ｎ−ビニルホルムアミド、Ｎ−ビニルアセトアミド、Ｎ−メチル−Ｎ−ビニルアセトアミドなどを挙げることができる。
【００１８】
Ｎ−ビニルピロリドン系単量体の具体例として、Ｎ−ビニル−２−ピロリドン、Ｎ−ビニル−３−プロピル−２−ピロリドン、Ｎ−ビニル−５，５−ジメチル−２−ピロリドン、Ｎ−ビニル―３，５−ジメチル−２−ピロリドンなどを挙げることができる。また、Ｎ−ビニルカプロラクタム系単量体として、具体的には、Ｎ−ビニル−２−カプロラクタム、Ｎ−ビニル−３−プロピル−２−カプロラクタムなどを挙げることができる。
【００１９】
Ｎ−ビニルアミド系単量体の中でも、単量体の人体に対する安全性の点から、上記式（IV）で示される単量体およびＮ−ビニル−２−カプロラクタムが好ましく、入手のし易さの点から好ましいのは、Ｎ−ビニルホルムアミド、Ｎ−ビニルアセトアミド、Ｎ−メチル−Ｎ−ビニルアセトアミドおよびＮ−ビニル−２−カプロラクタムであり、水溶性フィルムの形態安定性および水溶性フィルムで繊維柔軟剤を包装した包装体の溶解性の点から好ましいのは、Ｎ−ビニル−２−カプロラクタムおよびＮ−ビニルアセトアミドである。
【００２０】
本発明において用いることができるオキシアルキレン系単量体は、具体的にはオキシアルキレン基を有する不飽和単量体などであり、その例として、ポリオキシエチレン（メタ）アリルエーテル、ポリオキシプロピレン（メタ）アリルエーテル、ポリオキシエチレン（メタ）アクリレート、ポリオキシプロピレン（メタ）アクリレート、ポリオキシエチレン（メタ）アクリルアミド、ポリオキシプロピレン（メタ）アクリルアミド、ポリオキシエチレン（１−（メタ）アクリルアミド−１，１−ジメチルプロピル）エステル、ポリオキシエチレンビニルエーテル、ポリオキシプロピレンビニルエーテルなどを挙げることができる。
【００２１】
また、ビニルエーテル系単量体の具体例としては、メチルビニルエーテル、エチルビニルエーテル、ｎ−プロピルビニルエーテル、ｉ−プロピルビニルエーテル、ｎ−ブチルビニルエーテル、エチレングリコールビニルエーテル、１，３−プロパンジオールビニルエーテル、１，４−ブタンジオールビニルエーテルなどを挙げることができる。
【００２２】
非イオン性単量体単位を含有するＰＶＡの製法としては、ビニルエステル系単量体と非イオン性単量体を共重合して得られたビニルエステル系重合体を、アルコールまたはジメチルスルホキシドなどの溶液中でけん化する方法などが挙げられる。
【００２３】
上記のビニルエステル系単量体としては、ギ酸ビニル、酢酸ビニル、プロピオン酸ビニル、バレリン酸ビニル、カプリン酸ビニル、ラウリン酸ビニル、ステアリン酸ビニル、安息香酸ビニル、ピバリン酸ビニルおよびバーサティック酸ビニルなどが挙げられ、これらの中でも工業的にＰＶＡを得るという観点からは酢酸ビニルが好ましい。
【００２４】
本発明において、ＰＶＡは、本発明の効果を損なわない範囲であれば、分子の主鎖中に、ビニルアルコール単位、ビニルエステル系単量体単位および上記した非イオン性単量体単位以外に他の単量体単位を含有していてもよい。そのような単量体単位としては、エチレン、プロピレン、１−ヘキセンなどのα−オレフィン類；アクリルアミド、Ｎ−メチルアクリルアミドなどのアクリルアミド誘導体；メタクリルアミド、Ｎ−メチルメタクリルアミドなどのメタクリルアミド誘導体；アリルアセテート；プロピルアリルエーテルなどのアリルエーテル類；ビニルトリメトキシシランなどのビニルシラン類；酢酸イソプロペニル；３−ブテン−１−オール、４−ペンテン−１−オール、５−ヘキセン−１−オール、７−オクテン−１−オール、３−メチル−３−ブテン−１−オールなどのヒドロキシ基を含有するα−オレフィン類；エチレンスルホン酸、アリルスルホン酸、メタアリルスルホン酸、２−アクリルアミド−２−メチルプロパンスルホン酸などに由来するスルホン酸基を有する単量体；ビニロキシエチルトリメチルアンモニウムクロライド、ビニロキシブチルトリメチルアンモニウムクロライド、ビニロキシエチルジメチルアミン、ビニロキシメチルジエチルアミン、Ｎ−アクリルアミドメチルトリメチルアンモニウムクロライド、Ｎ−アクリルアミドエチルトリメチルアンモニウムクロライド、Ｎ−アクリルアミドジメチルアミン、アリルトリメチルアンモニウムクロライド、メタアリルトリメチルアンモニウムクロライド、ジメチルアリルアミン、アリルエチルアミンなどに由来するカチオン基を有する単量体などを共重合して得られる単量体単位が挙げられる。これらの単量体単位の含有量は、使用される目的や用途などによっても異なるが、通常５モル％以下であり、好ましくは２モル％以下である。
【００２５】
前述したビニルエステル系単量体および非イオン性単量体の共重合の方法としては、塊状重合法、溶液重合法、懸濁重合法、乳化重合法などの公知の方法が挙げられる。その中でも、無溶媒で重合する塊状重合法またはアルコールなどの溶媒中で重合する溶液重合法が通常採用される。溶液重合時に溶媒として使用されるアルコールとしては、メタノール、エタノール、プロパノールなどの低級アルコールが挙げられる。共重合に使用される開始剤としては、２，２’−アゾビス（イソブチロニトリル）、２，２’−アゾビス（２，４−ジメチルバレロニトリル）などのアゾ系開始剤、および過酸化ベンゾイル、ｎ−プロピルパーオキシカーボネートなどの過酸化物系開始剤などの公知の開始剤が挙げられる。重合温度については特に制限はないが、０℃〜１５０℃の範囲が適当である。
【００２６】
本発明においてＰＶＡは、前述のビニルエステル系単量体および非イオン性単量体を共重合して得られたビニルエステル系重合体を、通常、メタノールなどのアルコール類、酢酸メチルなどのエステル類、ジメチルスルホキシドなどから選ばれる１種または２種以上の溶媒中、好ましくはメタノールなどの低級アルコール溶媒中で、水酸化カリウム、水酸化ナトリウムなどのアルカリ触媒または硫酸、塩酸、ｐ−トルエンスルホン酸などの酸触媒を用いてけん化することにより得ることができる。けん化反応の条件は、ビニルエステル系重合体の構造や目的とするビニルアルコール系重合体のけん化度によって適宜調整されるが、通常、けん化反応は、触媒とビニルエステル系単量体の使用モル比（触媒／ビニルエステル系単量体）を０．００１〜５．０の範囲にし、２０〜１８０℃の反応温度にて０．１〜２０の反応時間で実施される。けん化方法としてはバッチ法または連続法などの公知の方法が適用可能である。
【００２７】
一般に、水溶性フィルムには、高温多湿の地域や寒冷地での使用にも耐え得るように強度やタフネスが要求され、特に低温での耐衝撃性が必要とされる。本発明の水溶性フィルムには、低温における耐衝撃性を向上させることを目的として、水溶性フィルムのガラス転移点を下げるために種々の可塑剤を配合することができる。さらに、水に対する溶解性や加工性を向上させる目的で可塑剤を配合することもできる。
【００２８】
本発明の水溶性フィルムに配合することができる可塑剤としては、ＰＶＡの可塑剤として一般に用いられているものであれば特に制限はなく、例えば、グリセリン、ジグリセリン、ジエチレングリコール、トリエチレングリコール、プロピレングリコール、ジプロピレングリコール、トリメチロールプロパン、ペンタエリスリトール、１，３−ブタンジオールなどの多価アルコール類；ポリエチレングリコール、ポリプロピレングリコールなどのポリエーテル類；ポリビニルピロリドンなどのポリビニルアミド類；ビスフェノールＡ、ビスフェノールＳなどのフェノール誘導体；Ｎ−メチルピロリドン、ジメチルアセトアミドなどのアミド化合物；グリセリン、ペンタエリスリトール、ソルビトールなどの多価アルコールにエチレンオキサイドを付加した化合物や水などが挙げられ、これらは１種または２種以上を用いることができる。これらの可塑剤の中でも、水溶性フィルムの水溶性を向上させる目的には、グリセリン、ジグリセリン、ジエチレングリコール、トリエチレングリコール、プロピレングリコール、ジプロピレングリコール、トリメチロールプロパン、ポリエチレングリコール、ポリビニルピロリドンを用いるのが好ましく、特に可塑剤のブリードアウトによる水溶性フィルムの水溶性の低下を抑制する効果の点から、グリセリン、ジグリセリン、トリメチロールプロパン、ポリエチレングリコール、ポリビニルピロリドンを用いるのが特に好ましい。
【００２９】
可塑剤としてポリエチレングリコールを用いる場合のポリエチレングリコールの分子量について特に制限はないが、ＰＶＡとの相溶性およびブリードアウトによる水溶性フィルムの水溶性の低下を抑制する効果の点から数平均分子量が１００〜１０００であることが好ましい。ポリビニルピロリドンの分子量についても特に制限はないが、ＰＶＡとの相溶性の点から重量平均分子量で１０００〜２００００であることが好ましい。
【００３０】
可塑剤の配合量は、ＰＶＡ１００重量部に対して１〜５０重量部であり、１〜３５重量部がさらに好ましい。可塑剤の配合量が１重量部未満の場合には、可塑剤を配合することによる効果が発現しない場合がある。一方、可塑剤の配合量が５０重量部を超える場合には、可塑剤のブリードアウトが大きくなり、得られる水溶性フィルムの耐ブロッキング性が低下する場合がある。水溶性フィルム中の可塑剤が包装体の内容物に移行するような場合には、水溶性フィルムの水に対する溶解性が経時的に低下したり、あるいは低温における柔軟性が低下することがあるので、このような事態を避けるため、可塑剤の配合量をＰＶＡ１００重量部に対して１〜２０重量部にするのがよい。
【００３１】
可塑剤の配合量が多くなるほど水溶性フィルムのヒートシール温度が低下し、水溶性フィルムを製袋する際の生産性が向上する傾向がある。このような観点から、得られる水溶性フィルムのヒートシール温度が１７０℃以下となるような割合で可塑剤を配合するのが好ましく、１６０℃以下となるような割合で可塑剤を配合するのがさらに好ましい。
【００３２】
可塑剤の配合量は、得られる水溶性フィルムの強度およびヤング率の大きさに影響を与えやすいが、水溶性フィルムの実用性の点からは、フィルムの強度は０．５ｋｇ／ｍｍ^２以上であるのが好ましく、０．８ｋｇ／ｍｍ^２以上であるのがさらに好ましい。得られる水溶性フィルムの形態安定性および製袋機などの工程通過性の点から、水溶性フィルムのヤング率は０．５ｋｇ／ｍｍ^２以上であるのが好ましく、１．０ｋｇ／ｍｍ^２以上であるのがさらに好ましく、このような範囲のヤング率を有する水溶性フィルムが得られるように、可塑剤を配合するのが好ましい。
【００３３】
本発明の水溶性フィルムには、必要に応じて糖類を配合することができ、これにより、水溶性フィルムの水への溶解性および形態安定性をさらに高めることができる。糖類としては、グルコースなどの単糖類、オリゴ糖、多糖類およびマンニットなどの鎖状糖アルコールが挙げられる。多糖類としては、澱粉、セルロース、キチン、キトサン、ヘミセルロース、ペクチン、プルラン、寒天、アルギン酸、カラギーナン、デキストリン、トレハロースなどが挙げられ、これらのうち１種または２種以上を用いることができる。鎖状糖アルコールとしては、トレイット、エリトリットなどの炭素数４のテトリット類、アラビット、キシリットなどの炭素数５のペンチット類、グリシット、マンニット、ソルビットなどの炭素数６のヘキシット類が挙げられる。水溶性フィルムの冷水への溶解性が良好な点から、糖類のなかでも澱粉の配合が特に好ましい。澱粉としては、例えば、トウモロコシ、馬鈴薯などの生澱粉、これらに物理的または化学的処置を施した加工澱粉（デキストリン、酸化澱粉、エーテル化澱粉、カチオン化澱粉など）などを用いることができる。
【００３４】
糖類の配合量は、水溶性フィルムの形態安定性、および水溶性フィルムで繊維柔軟剤を包装した包装体の冷水溶解性の点から、ＰＶＡ１００重量部に対して１〜３０重量部であることが好ましく、１〜２０重量部であることがさらに好ましく、１〜１０重量部であることが特に好ましい。糖類の配合量が１重量部より小さいと、水溶性フィルムの形態安定性および包装体の冷水への溶解性の向上効果が発現しない場合がある。一方、糖類の配合量が３０重量部より多いと、特に包装体を少量の水で溶解する場合（高カチオン濃度時）にかえって水への溶解性が低下することがあり好ましくない。
【００３５】
本発明の水溶性フィルムには、さらに必要に応じて、無機フィラーを配合することができる。用いることができる無機フィラーとしては、例えば、シリカ、重質、軽質または表面処理された炭酸カルシウム、水酸化アルミニウム、酸化アルミニウム、酸化チタン、珪藻土、硫酸バリウム、硫酸カルシウム、ゼオライト、酸化亜鉛、珪酸、珪酸塩、マイカ、炭酸マグネシウム、カオリン、ハロサイト、パイロフェライト、セリサイトなどのクレー、タルクなどを挙げることができ、これらのうち１種または２種以上を用いることができる。これらの中でも、特にＰＶＡへの分散性の点から、シリカおよびタルクを用いることが好ましい。無機フィラーの平均粒子径は、水溶性フィルムのブロッキング防止性の点から１μｍ以上が好ましく、一方、ＰＶＡへの分散性の点から１０μｍ以下が好ましい。無機フィラーを配合することにより発現する水溶性フィルムのブロッキング防止性と、ＰＶＡへの無機フィラーの分散性の両方の要求性能を満足させるには、平均粒子径が１〜７μｍ程度の大きさの無機フィラーを用いるのがより好ましい。
【００３６】
無機フィラーの配合量は、水溶性フィルムのブロッキング防止性およびＰＶＡへの無機フィラーの分散性の点から、ＰＶＡ１００重量部に対して０．５〜２０重量部であることが好ましく、０．７〜１５重量部であることがより好ましく、１〜１０重量部であることが特に好ましい。なお、無機フィラーを２０重量部を超えて配合すると、ＰＶＡへの分散性が低下して無機フィラーが凝集してしまい、得られる水溶性フィルムの水溶性が低下する傾向がある。
【００３７】
本発明の水溶性フィルムには、さらに必要に応じて、着色剤、香料、増量剤、消泡剤、剥離剤、紫外線吸収剤、界面活性剤などの添加剤を適宜配合しても差し支えない。特に製膜装置のダイスやドラムなどの金属表面と、製膜したフィルムやフィルム原液との剥離性を向上させるために、ＰＶＡ１００重量部に対して界面活性剤を０．０１〜５重量部の割合で配合することが好ましい。また、本発明の水溶性フィルムには、必要に応じて、本発明の効果を損なわない範囲内で、本発明に用いられるＰＶＡとは異なる種類のＰＶＡ、カルボキシメチルセルロース、ポリアクリルアミド、ポリアクリル酸またはその塩、メチルセルロース、ヒドロキシメチルセルロースなどの水溶性高分子を配合してもよい。特にフィルムの水溶性を向上させるという観点から、低粘度タイプのカルボキシメチルセルロースを添加することが好ましい。
【００３８】
本発明の水溶性フィルムを製造するにあたり、その製造原料は、前記のＰＶＡに、必要に応じて、可塑剤、糖類、無機フィラーやその他の成分を配合し、撹拌槽中にて溶媒に溶解または分散させる方法や押出機中にて溶融混練する方法など、公知の方法で混合することにより調製することができる。
【００３９】
本発明の水溶性フィルムは、一般にフィルムを製膜する際に用いられている製膜方法、例えば、流延製膜法、湿式製膜法、乾式製膜法、押出製膜法、溶融製膜法、コート法、インフレーション製膜法などの製膜方法で製造することができる。例えば、本発明の水溶性フィルムの製膜に必要な成分を、水、ジメチルスルホキシド、ジメチルホルムアミド、ジメチルアセトアミド、メタノール、ｎ−プロパノール、ｉ−プロパノール、フェノールなどの溶媒の１種または２種以上の混合液に溶解し、均一な製膜原液を調製した後、流延製膜法などの製膜方法で製造することができる。この製膜原液の濃度は、粘度の点から７０重量％以下（溶媒の含有量が３０重量％以上）であることが好ましい。
【００４０】
本発明の水溶性フィルムの厚みは１０〜２００μｍであることが好ましく、フィルムの強度と水溶性のバランスの点から２０〜１５０μｍであるのがより好ましい。
【００４１】
本発明の水溶性フィルムのブロッキング防止性を向上させるために、必要に応じて、該水溶性フィルム表面をロールマット化したり、シリカや澱粉などのブロッキング防止用の粉体を水溶性フィルムに塗布したり、エンボス処理を行うことができる。フィルム表面のロールマット化は、製膜時に乾燥前のフィルムが接するロールに微細な凹凸を形成しておくことにより施すことができる。エンボス処理は一般にフィルムが形成された後で、熱や圧力を加えながらエンボスロールとゴムロールでニップすることで行うことができる。粉体の塗布はブロッキング防止の効果が大きいが、用途によっては使用できないことがあるため、ロールマット化やエンボス処理を施すことでブロッキング防止をはかるのが好ましく、ブロッキングの防止効果の大きさの点からロールマット化することが特に好ましい。
【００４２】
本発明の水溶性フィルムは、冷水への溶解速度が優れており、５℃水中での完全溶解時間（フィルムの厚さ４０μｍ）は好ましくは８０秒以下であり、より好ましくは６０秒以下であり、特に好ましくは４０秒以下である。本明細書でいう５℃水中での完全溶解時間とは、スライドマウント法により測定した値である。すなわち、厚さ４０μｍのフィルムを４０×４０ｍｍの正方形に切り、これをスライドマウントにはさみ、撹拌している５℃の水中に浸漬してフィルムが完全に溶解するまでの時間を測定した値である。なお、フィルムの厚さが４０μｍとは異なる場合の完全溶解時間とは、下記式（Ｖ）によりフィルムの厚さを４０μｍに換算した値である。
溶解時間（秒）＝（４０／フィルムの厚み（μｍ））^２×溶解時間（秒）…（Ｖ）
【００４３】
本発明の水溶性フィルムは、繊維柔軟剤を包装して包装体としたときの冷水溶解性が優れていることが特徴である。繊維柔軟剤を包装した後、１０分間室温で放置した包装体を４０×４０ｍｍの正方形に切り、これをスライドマウント法で測定した、５℃水中での完全溶解時間（フィルムの厚さ４０μｍ）は、好ましくは１２０秒以下であり、より好ましくは１００秒以下であり、特に好ましくは８０秒以下である。
【００４４】
また、本発明の水溶性フィルムは、繊維柔軟剤を包装した状態で長期に保存した場合でも溶解性が経時的に低下しにくいことも特徴の一つである。長期保存の促進試験として、繊維柔軟剤を水溶性フィルムで包装した包装体を３０℃、８０％ＲＨの恒温恒湿槽に入れて、２週間後に取り出し、前述の方法によりフィルムの溶解時間を測定する。繊維柔軟剤を包装した包装体を、室温で１０分間放置した後の溶解時間（Ａ）と保存促進試験後の溶解時間（Ｂ）の商（Ｂ／Ａ）は、３．０以下が好ましく、２．０以下がより好ましく、１．５以下がさらに好ましく、１．２０以下が特に好ましい。
【００４５】
本発明の水溶性フィルムを用いて繊維柔軟剤を包装するには、物品をフィルム包装するのに一般に採用されている方法を採用することができ、特に限定されない。繊維柔軟剤を包装する方法としては、繊維柔軟剤を包装後のフィルムを三方シール自動包装機などを用いてヒートシールしたり、フィルムの周縁部分を接着剤で接着し、得られた袋の開放部から繊維柔軟剤を充填した後、開放部をヒートシールするかまたは接着する方法などを例示することができる。
【００４６】
本発明の水溶性フィルムで繊維柔軟剤を包装した包装体は、冷水での溶解性に優れており、市販の洗濯機で使用した後に洗濯機内に残存する未溶解物を乾燥した固形分量は、好ましくは１．０ｇ以下であり、より好ましくは０．５ｇ以下、特に好ましくは０．３ｇ以下である。
【００４７】
本発明の水溶性フィルムにより包装することができる繊維柔軟剤の種類について特に制限はなく、繊維柔軟剤として一般家庭で日常使用されているものが挙げられる。その具体例として、ジ（硬化牛脂アルキル）ジメチルアンモニウムクロライド等の４級アンモニウム塩、メチルジ（硬化牛脂アルキル）アミン（特開昭５２−５９７９６５号公報）、アシル化アルカノールアミン（特開昭５８−６００７０号公報）等が挙げられるが、必ずしもこれらに限定されない。本発明の水溶性フィルムは、カチオン性界面活性剤を包装した場合でも水への溶解性が低下しないという特性を有することから、カチオン性界面活性剤を包装するのに適している。
【００４８】
包装に用いられる繊維柔軟剤は、水分率が１０重量％以下であることが好ましく、８重量％以下であることがより好ましく、５重量％以下であることが特に好ましい。繊維柔軟剤の水分率が１０重量％を超えると、水溶性フィルムで包装した場合に、該水溶性フィルム中の可塑剤が繊維柔軟剤側に移行して、水溶性フィルム中の可塑剤が減少する傾向があり、包装体の水への溶解性が低下することがある。繊維柔軟剤には、必要に応じて、エチルアルコール、イソプロピルアルコール、プロピレングリコール、多価アルコール等の溶剤、非イオン界面活性剤、塩化アンモニウムなどの水溶性塩、香料、着色剤、消泡剤、再付着防止剤、蛍光増白剤、殺菌剤、防縮剤、シリコーン化合物、無機電解質、抗菌剤、酸化防止剤、保存剤などが配合されていてもよい。
【００４９】
繊維柔軟剤がとりうる形態は固体、粉体、顆粒状、液体などであり、特に制限はない。繊維柔軟剤の代表的な形態は、ジ長鎖アルキル型４級アンモニウム塩を主成分とする分散溶液であるが、特開平６−３０６７６９号公報等に開示されているような粉末または錠剤でもよい。
【００５０】
本発明の包装体は、繊維柔軟剤の充填率が６０〜９８％であることが好ましく、７０％〜９５％であることがより好ましい。包装体における繊維柔軟剤の充填率が小さ過ぎると、包装体中に空気が多く含まれることになるので、包装体を洗濯機内に入れた場合に水中に沈むのが困難になり、溶解時間が長くなる傾向がある。このような理由から、繊維柔軟剤の充填率は６０％以上であることが好ましい。繊維柔軟剤の充填率が９８％を超えると、包装体が水中に早く沈み過ぎることになり、包装体が洗濯機の底に留まって水への溶解性が低下する傾向がある。
【００５１】
通常、繊維柔軟剤は最終の濯ぎ時に添加するが、その手間を省く方法として、洗濯機に別途引出しを設け、洗濯を開始するときにこの引出しに繊維柔軟剤入りの包装体を入れておいて、濯ぎの際に用いられる水の作用により包装体が洗濯機の槽内に流れ落ちるような構造にしておく方法が推奨される。このような構造の洗濯機に繊維柔軟剤入りの包装体を適用する場合には、通常引出し内に流れる水の量が洗濯槽内の水の量に比べて少ないため、少量の水で包装体が溶解し、槽内に流れ落ちる必要がある。この場合、包装体における繊維柔軟剤の充填率を変えることで空気量を調整するようにすれば、水が引出し内に流れてきた際、包装体が空気の浮力によって適度に浮き、その一方で下部が水と接触するため、少量の水でも包装体は溶解し、包装体が水に溶けない状態で引出し内に残ることがない。
【００５２】
【実施例】
以下に実施例を挙げて本発明をさらに詳しく説明するが、本発明はこれによって何ら限定されるものではない。なお、以下の実施例および比較例において、「部」および「％」は、特に断らない限り「重量部」および「重量％」をそれぞれ意味する。また、実施例および比較例において、フィルムの各種特性の測定および評価は以下の方法により行った。
【００５３】
［フィルムの溶解性の測定方法（１）］
５℃の恒温バスにマグネティックスターラーを設置した。１リットルの蒸留水を入れた１リットルのガラスビーカーを上記の恒温バスに入れ、５ｃｍの回転子を用いて３３０ｒｐｍで撹拌を行った。ビーカー内の蒸留水が５℃になった後、水溶性の測定を開始した。
フィルムを４ｃｍ×４ｃｍの正方形に切り、これをスライドマウントに挟み、撹拌している５℃の水中に浸漬してフィルムの溶解状態を観察し、フィルムが完全に溶解するまでの時間（秒数）を測定した。なお、フィルムの厚さが４０μｍとは異なる場合には、下記式（Ｖ）にしたがってフィルムの厚さ４０μｍの値に換算した。
【００５４】
溶解時間（秒）＝（４０／フィルムの厚み（μｍ））^２×溶解時間（秒）…（Ｖ）
【００５５】
［フィルムの溶解性の測定方法（２）］
フィルムから４．５ｃｍ×４．５ｃｍの袋を作り、その内部に繊維柔軟剤としてサファノールＰ−２００（三洋化成製）とヘキシレングリコールの混合液（重量比率は１：１）７ｇを入れ、熱シールして密封して包装体を作製した。包装して１０分後に包装体を４ｃｍ×４ｃｍに切り取り、５℃における水溶性を評価した。
【００５６】
［フィルムの保存安定性の評価方法］
フィルムから４．５ｃｍ×４．５ｃｍの袋を作り、内部に繊維柔軟剤としてサファノールＰ−２００（三洋化成製）とヘキシレングリコールの混合液（重量比率は１：１）７ｇを入れ、熱シールして密封して包装体を作製した。長期保存の促進試験として、この包装袋を３０℃、８０％ＲＨの恒温恒湿槽に入れ、２週間後に取り出して、包装していたフィルムの水溶性を前述の方法にしたがって測定した。
フィルムの保存安定性は、繊維柔軟剤を包装した包装体を用い、これを室温で１０分間放置した後の溶解時間（Ａ）と保存促進試験後の溶解時間（Ｂ）の商（Ｂ／Ａ）を求め、その値の大小で評価した。
【００５７】
［包装体の溶解性の評価方法］
フィルムから４．５ｃｍ×４．５ｃｍの袋を作り、内部に繊維柔軟剤としてサファノールＰ−２００（三洋化成製）とヘキシレングリコールの混合液（重量比率は１：１）７ｇを入れ、熱シールして密封して包装体を作製した。市販の洗濯機（シャープ製ドラム式乾燥洗濯機）を用いて、繊維柔軟剤専用の引出しに該包装体を入れて洗濯機を運転し、洗濯後に引出し内の残存物を集めて、１０５℃で６時間乾燥した後の重量を測定し、評価した。
【００５８】
［ヤング率および強度の測定方法］
幅１０ｍｍのフィルムを、２０℃、６５％ＲＨの雰囲気のもとで１週間調湿した後、オートグラフで引張り試験を行った。チャック間隔は５０ｍｍ、引張り速度は５００ｍｍ／ｍｉｎであった。
【００５９】
合成例１（変性ＰＶＡの合成）
撹拌機、還流冷却管、窒素導入管および温度計を取り付けた５Ｌの反応器に、酢酸ビニル単量体１１００ｇ、メタノール１８５２．４ｇ、Ｎ−ビニル−２−カプロラクタムの３０％メタノール溶液５３．７ｇを仕込み、窒素ガスを３０分バブリングして脱気した。反応器の昇温を開始し、内温が６０℃となったところで、２，２’−アゾビス（イソブチロニトリル）３．５ｇを添加し重合を開始した。Ｎ−ビニル−２−カプロラクタムの３０％メタノール溶液を酢酸ビニル単量体とのモル比率が一定になるように逐次添加しながら重合を行い、４．５時間後に冷却して重合を停止した。このときの固形分濃度は４５％であった。次いで３０℃減圧下でメタノールを時々添加しながら未反応の酢酸ビニル単量体の除去を行い、ポリ酢酸ビニル共重合体のメタノール溶液（濃度３８％）を得た。次に、メタノールを加えて濃度を３５％に調整したポリ酢酸ビニル共重合体のメタノール溶液にアルカリモル比（ＮａＯＨのモル数／酢酸ビニル単量体単位のモル数）０．００４のＮａＯＨメタノール溶液（１０％濃度）を添加してけん化反応を行った。得られたＰＶＡ（ＰＶＡ−１）のけん化度は８２．１モル％であった。
【００６０】
得られたＰＶＡ１ｇにメタノール１０ｇを加え、６０℃に加温してＰＶＡを膨潤させた後、ＮａＯＨのメタノール溶液（１０％濃度）５ｇを加えて６０℃で３時間撹拌したものについて、メタノールソックスレー抽出を３日間実施し、次いで乾燥してＰＶＡの精製物を得た。該ＰＶＡ精製物のプロトンＮＭＲ測定から求めたＮ−ビニル−２−カプロラクタム単量体単位の変性量は２．０モル％であった。また、該ＰＶＡの平均重合度を常法のＪＩＳ Ｋ６７２６に準じて測定したところ、５００であった。
【００６１】
コモノマーの種類と変性量、ＰＶＡの重合度およびけん化度が下記の表１になるように重合条件およびけん化条件を変更したこと以外はＰＶＡ−１と同様にして変性ＰＶＡ（ＰＶＡ−２〜１１、ＰＶＡ−１４〜２２）を合成した。合成した変性ＰＶＡの内容について下記の表１に示す。
【００６２】
合成例２（無変性ＰＶＡ）
攪拌機、還流冷却管、窒素導入管および温度計を取り付けた５Ｌ反応器に酢酸ビニル単量体９００ｇ、メタノール２１００ｇを仕込み、窒素ガスを３０分バブリングして脱気した。反応器の昇温を開始し、内温が６０℃となったところで、２，２’−アゾビス（イソブチロニトリル）１．０ｇを添加し重合を開始した。５時間後に冷却して重合を停止した。このときの固形分濃度は４５％であった。次いで３０℃減圧下にメタノールを時々添加しながら未反応酢酸ビニルモノマーの除去を行い、ポリ酢酸ビニルのメタノール溶液（濃度３８％）を得た。次に、メタノールを加えて濃度を３５％に調整したポリ酢酸ビニル共重合体のメタノール溶液にアルカリモル比（ＮａＯＨのモル数／酢酸ビニル単量体単位のモル数）０．００４のＮａＯＨメタノール溶液（１０％濃度）を添加してけん化反応を行った。得られたＰＶＡ（ＰＶＡ−１２）のけん化度は８０．５モル％であった。
【００６３】
得られたＰＶＡ１ｇにメタノール１０ｇを加え、６０℃に加温してＰＶＡを膨潤させた後、ＮａＯＨのメタノール溶液（１０％濃度）５ｇを加えて６０℃で３時間撹拌したものについて、メタノールソックスレー抽出を３日間実施し、次いで乾燥してＰＶＡの精製物を得た。該ＰＶＡの平均重合度を常法のＪＩＳ Ｋ６７２６に準じて測定したところ、５００であった。
【００６４】
重合条件およびけん化条件を変更したこと以外はＰＶＡ−１２と同様にして無変性ＰＶＡ（ＰＶＡ−１３、２３および２４）を合成した。合成した無変性ＰＶＡの内容について下記の表１に示す。
【００６５】
実施例１
表１に示されるＰＶＡ（ＰＶＡ−１）１００重量部に対し、可塑剤としてグリセリン１５重量部および水を添加して均一な５％水溶液（含水率９０％）を作成し、ポリエステルフィルム上に流延して室温で乾燥した後、ポリエステルフィルムから剥離することにより、厚さ４０μｍのフィルムを得た。得られたフィルムに１００℃で１０分間熱処理を行った。このフィルムの水溶性を測定したところ、５℃水中での完全溶解時間は３３秒であった。また、フィルムの腰に代表される工程通過性などの取扱性の指標として、２０℃、６５％ＲＨに調湿してヤング率の測定を行ったところ０．８ｋｇ／ｍｍ^２、強度は１．７ｋｇ／ｍｍ^２であった。
繊維柔軟剤を包装した後のフィルムの溶解性を評価したところ、繊維柔軟剤を包装して１０分後のフィルムの５℃水中での完全時間は６８秒であった。また、３０℃８０％ＲＨの恒温恒湿槽に入れて、２週間後に取り出した時のフィルムの５℃水中での完全時間は６９秒であり、溶解性の経時変化は１．０であり、溶解性の低下は見られなかった。
繊維柔軟剤を包装した包装体の溶解性を評価したところ、洗濯機引出しの残存物の乾燥重量は０．０１ｇであった。
【００６６】
実施例２〜５および参考例１〜１１
ＰＶＡの内容、可塑剤および糖類の種類と配合量、ならびに繊維柔軟剤の包装体への充填率を下記の表１および表２のように変更したこと以外は、実施例１と同様にしてフィルムを作製し、各種評価を行った。評価結果を下記の表３に示す。
【００６７】
比較例１〜１０
ＰＶＡの内容を下記の表１のように変更したこと以外は、実施例１と同様にしてフィルムを製造し、各種評価を行った。評価結果を下記の表３に示す。
【００６８】
【表１】

【００６９】
【表２】

【００７０】
【表３】

【００７１】
上記の表３の結果から、ＰＶＡ−１〜１３を用いて作製された本発明の水溶性フィルムは、冷水に対する溶解性が優れている上に、強度およびヤング率などの実用物性も優れていることがわかる。さらに、本発明の水溶性フィルムは、繊維柔軟剤を包装した状態で長期に保存した場合でも溶解性が低下しにくく、繊維柔軟剤包装用フィルムとして好適であることがわかる。
非イオン性単量体単位が１０モル％を超える変性ＰＶＡからなるフィルムは、強度およびヤング率が低い（比較例１）。ビニルアルコール単位が９０モル％を越えるＰＶＡからなるフィルムは、繊維柔軟剤を包装した際のフィルムの溶解性が劣り、洗濯機で包装体を用いた際に柔軟剤専用の引出し内に溶け残りが多い（比較例２、６、７、１０）。ビニルアルコール単位が７５モル％より小さい非イオン性基変性ＰＶＡからなるフィルムは、強度およびヤング率が低く（比較例３）、ビニルアルコール単位が７５モル％より小さい無変性ＰＶＡからなるフィルムは、繊維柔軟剤を包装した場合の保存安定性が低い（比較例１１）。重合度（Ｐ）が｛（Ｘ−９３）^２×１６／３＋３００｝より大きいＰＶＡからなるフィルムは、繊維柔軟剤を包装した際のフィルムの溶解性が劣る（比較例４）。重合度（Ｐ）が｛１００×Ｚ＋１００｝より小さいＰＶＡからなるフィルムは、フィルムの強度が劣る（比較例５）。イオン性基変性ＰＶＡからなるフィルムは、繊維柔軟剤を包装した際のフィルムの溶解性が劣るだけでなく、時間の経時とともに溶解性が低下する（比較例８、９）。
【００７２】
【発明の効果】
本発明の水溶性フィルムは、冷水に対する溶解性が優れており、特に繊維柔軟剤を包装した際に高い溶解性を有しているのみならず、繊維柔軟剤を包装した状態で長期に保存した場合でも溶解性が低下しにくいため、繊維柔軟剤包装用フィルムとして好適に用いられる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water-soluble film and a package using the same. More specifically, the present invention contains polyvinyl alcohol units, vinyl ester monomer units and nonionic monomer units in the main chain of the molecule, and the content and degree of polymerization of these units are specified. The present invention relates to a water-soluble film made of a vinyl alcohol polymer and a package formed by packaging a fiber softener with the water-soluble film.
[0002]
[Prior art]
In recent years, as a method of using various chemicals including laundry detergents, agricultural chemicals, bleaching agents, toiletry products, and industrial chemicals, a certain amount of these chemicals are hermetically sealed with a water-soluble film (unit packaging) and used. At times, the packaging form is put into water, and the contents are used together with the packaging film dissolved or dispersed in water. Advantages of this unit packaging are that it can be used without direct contact when using dangerous chemicals on the body, the contents are packaged in a certain amount, so there is no need to weigh when used, and the medicine is packaged For example, there is no need for processing after use of the container.
[0003]
Many reports have already been made about sealing and packaging various chemicals using a water-soluble film. For example, Patent Document 1, Patent Document 2, Patent Document 3 and the like describe that a single detergent used for washing clothes is unit-wrapped with a water-soluble film made of partially saponified polyvinyl alcohol. However, the water-soluble film made of partially saponified polyvinyl alcohol has a problem that the solubility of the film at low temperature is not sufficient, or the solubility in water decreases when stored for a long time in the state of packaging with an alkaline detergent. is there.
In order to solve this problem, an attempt has been made to improve the solubility of a water-soluble film in water by introducing an anionic group into polyvinyl alcohol. As an example of using a water-soluble film made of polyvinyl alcohol modified with an anionic group, a sheet-like detergent package in which a water-soluble film is bonded to both sides of a layer containing a detergent composition is known (for example, Patent Documents). 4, see Patent Document 5). In addition, a liquid detergent is packaged using a water-soluble film made of polyvinyl alcohol modified with an anionic group (for example, see Patent Document 6), or an alkaline substance is packaged (for example, Patent Document 7, Patent Document). 8) Examples are also known.
[0004]
As for the fiber softener, a liquid type containing 3 to 15% by weight of a cationic surfactant has been mainly used in the past, but in recent years, research for increasing the concentration is underway in order to reduce the amount used. . In parallel with this, the fiber softener is required to have a packaging form of unit packaging with a water-soluble film. However, when a fiber softener is packaged using a water-soluble film made of polyvinyl alcohol modified with an anionic group, the solubility of the package in cold water is significantly reduced, or the fiber softener is packaged for a long time. There is a problem that the solubility in water decreases over time when stored in a container. Although the reason is not clear, it is considered that an anionic group part contained in polyvinyl alcohol and a cationic substance which is a main component of the fiber softener cause an interaction. As a method for solving this problem, it has been proposed to introduce a specific unsaturated compound into polyvinyl alcohol (see, for example, Patent Document 9 and Patent Document 10). In these patent documents, as examples, examples in which a laundry composition such as a detergent, a bleaching agent, a fiber softener, and a paste are packaged are described. However, when the present inventors examined, when a fiber softener was packaged using a water-soluble film made of polyvinyl alcohol modified with a specific unsaturated compound described in these patent documents, The solubility of the water-soluble film in water is not always sufficient, and there is still room for improvement. Furthermore, the water-soluble film made of polyvinyl alcohol modified with a specific unsaturated compound described in the patent document has solubility in water when stored for a long time in a state where the fiber softener is packaged. There is also a problem that it falls.
[0005]
Prior art document information related to the invention of this application includes the following.
[Patent Document 1]
JP-A-61-57700 (first page, second page, claims 1 and 2)
[Patent Document 2]
Japanese Patent Laid-Open No. 63-8497 (first page, second page, claims)
[Patent Document 3]
JP 63-12467 (first page, second page, claims)
[Patent Document 4]
Japanese Patent Laid-Open No. 10-72599 (2nd, 4th, 5th pages, claims 1, 4 and 5)
[Patent Document 5]
Japanese Unexamined Patent Publication No. 2000-34494 (page 2, page 6, claim 1)
[Patent Document 6]
Japanese Patent No. 3262406 (pages 1 to 4, claim 1)
[Patent Document 7]
JP-A-9-324096 (2nd page, 3rd page, claim 1)
[Patent Document 8]
JP-A-10-60207 (pages 2 to 4, claims 1 to 3)
[Patent Document 9]
JP 2002-3896 (2nd page, 4th page, 6th to 9th page, claim 1)
[Patent Document 10]
JP 2002-3897 A (pages 2 to 4, pages 6 to 9, claim 1)
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a water-soluble film that is excellent in solubility in cold water and that is particularly suitable for packaging of a fabric softener. Furthermore, another object of the present invention is to provide a package that has excellent solubility in cold water when the fiber softener is packaged with a water-soluble film and that does not decrease in solubility over time. It is to provide.
[0007]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have found that the main chain of the molecule contains a polyvinyl alcohol unit, a vinyl ester monomer unit, a nonionic monomer unit, and the content and degree of polymerization of these units. The inventors have found that the specified polyvinyl alcohol polymer is extremely useful in producing the target water-soluble film, and have completed the present invention.
[0008]
That is, the present invention includes a vinyl alcohol containing a vinyl alcohol unit, a vinyl ester monomer unit and a nonionic monomer unit in the main chain of the molecule and satisfying the following formulas (I) to (III): Water-soluble film made of a polymer.
75 ≦ X ≦ 90 (I)
0 ≦ Z ≦ 10 (II)
100 × Z + 100 ≦ P ≦ (X−93)²× 16/3 + 300 (III)
X: Content of vinyl alcohol unit (mol%)
Z: Content of nonionic monomer unit (mol%)
P: Degree of polymerization of vinyl alcohol polymer
[0009]
Furthermore, the present invention provides a vinyl alcohol containing a vinyl alcohol unit, a vinyl ester monomer unit and a nonionic monomer unit in the main chain of the molecule and satisfying the following formulas (I) to (III): Water-soluble film made of a polymer.
75 ≦ X ≦ 90 (I)
0.1 ≦ Z ≦ 10 (II ′)
100 × Z + 100 ≦ P ≦ (X−93)²× 16/3 + 300 (III)
X: Content of vinyl alcohol unit (mol%)
Z: Content of nonionic monomer unit (mol%)
P: Degree of polymerization of vinyl alcohol polymer
[0010]
The water-soluble film of the present invention has the property of being excellent in solubility in cold water, and the package body in which the fiber softener is packaged with the water-soluble film has excellent solubility in cold water. Furthermore, it has the characteristic that the solubility does not decrease with the passage of time.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The vinyl alcohol polymer used in the present invention (hereinafter, the vinyl alcohol polymer may be abbreviated as PVA) is a vinyl alcohol unit, a vinyl ester monomer unit and a nonionic substance in the main chain of the molecule. A vinyl alcohol polymer (I) containing monomer units and satisfying the following formulas (I) to (III):
75 ≦ X ≦ 90 (I)
0 ≦ Z ≦ 10 (II)
100 × Z + 100 ≦ P ≦ (X−93)²× 16/3 + 300 (III)
X: Content of vinyl alcohol unit (mol%)
Z: Content of nonionic monomer unit (mol%)
P: Degree of polymerization of vinyl alcohol polymer
A vinyl alcohol polymer (II) containing a vinyl alcohol monomer unit, a vinyl ester monomer unit and a nonionic monomer unit in the main chain of the molecule, and satisfying the following formulas (I) to (III) It is necessary to be.
75 ≦ X ≦ 90 (I)
0.1 ≦ Z ≦ 10 (II ′)
100 × Z + 100 ≦ P ≦ (X−93)²× 16/3 + 300 (III)
In the above formula, X, Z and P are as defined above.
[0012]
With respect to the vinyl alcohol polymer (I), when the content (x) of the vinyl alcohol unit is less than 75 mol%, the strength of the film is weakened and the practical physical properties as a packaging film may not be sufficient. . When content (X) of a vinyl alcohol unit exceeds 90 mol%, the cold water solubility of the package which packaged the fiber softening agent may not be enough, and it is unpreferable. When the content (Z) of the nonionic monomer unit exceeds 10 mol% for the vinyl alcohol polymer (I), it is difficult to form a film or the strength of the film is weakened and packaging Practical physical properties as a film for use are not sufficient, which is not preferable. When the degree of polymerization (P) of the vinyl alcohol polymer (I) is less than (100 × Z + 100), it is difficult to produce PVA or film, or the film strength is not sufficient Is not preferable. The degree of polymerization (P) of the vinyl alcohol polymer (I) is {(X-93)²When exceeding * 16/3 + 300}, the cold water solubility of the package body in which the fiber softener is packaged may not be sufficient.
[0013]
For the vinyl alcohol polymer (II), when the content (X) of the vinyl alcohol unit is less than 75 mol%, the strength of the film is weakened, and the practical physical properties as a packaging film may not be sufficient, which is not preferable. . When content (X) of a vinyl alcohol unit exceeds 90 mol%, the cold water solubility of the package which packaged the fiber softening agent may not be enough, and it is unpreferable. When the content (Z) of the nonionic monomer unit is less than 0.1 mol% for the vinyl alcohol polymer (II), the cold water solubility of the packaging body in which the fiber softener is packaged is not sufficient. Or when the fiber softener is packaged and stored for a long time, the solubility in water may decrease with time, which is not preferable. When the content (Z) of the nonionic monomer unit exceeds 10 mol%, it is difficult to form a film or the strength of the film is weak and the practical properties as a packaging film are not sufficient. Is not preferable. When the degree of polymerization (P) of the vinyl alcohol polymer (II) is less than (100 × Z + 100), it is difficult to produce PVA or film, or the film strength is not sufficient Is not preferable. The degree of polymerization (Y) of the vinyl alcohol polymer (I) is {(X-93)²When exceeding * 16/3 + 300}, the cold water solubility of the package body in which the fiber softener is packaged may not be sufficient.
In the present invention, cold water means water at 0 ° C. to 40 ° C.
The degree of polymerization and saponification of PVA are measured according to the method described in JIS.
[0014]
The content (mol%) of the vinyl ester monomer unit contained in the vinyl alcohol polymer (I) is such that the vinyl alcohol polymer (I) is a vinyl alcohol unit, a vinyl ester monomer unit and a non-ion. In the case where the monomeric monomer unit is included, the content is the amount excluding the content (X) of the vinyl alcohol unit and the content (Z) of the nonionic monomer unit, and the vinyl alcohol polymer (I) When it is composed of a vinyl alcohol unit, a vinyl ester monomer unit, a nonionic monomer unit and another monomer unit, the content of the vinyl alcohol unit (X), the nonionic monomer unit This is the amount excluding the content (Z) and the content (mol%) of other monomer units.
The same applies to the content of the vinyl ester monomer unit contained in the vinyl alcohol polymer (II).
[0015]
Although there is no restriction | limiting in particular about the kind of nonionic monomer unit contained in a vinyl alcohol-type polymer, From the point of the solubility to the cold water of the package body which wrapped the fiber softener with the water-soluble film, it is N-vinylamide type | system | group. Monomers, oxyalkylene monomers, and vinyl ether monomers are preferable. Among them, the solubility of the package in water is less likely to change over time, and is high even when dissolved in a small amount of water. An N-vinylamide monomer is more preferable in view of solubility.
[0016]
The N-vinylamide monomer that can be preferably used in the present invention includes a monomer represented by the following formula (IV), an N-vinylcaprolactam monomer, and an N-vinylpyrrolidone monomer.
[Chemical 2]

[0017]
In the above formula (IV), R¹Examples of the alkyl group having 1 to 3 carbon atoms represented by the formula include a methyl group, an ethyl group, a propyl group, and an isopropyl group.²Examples of the alkyl group having 1 to 5 carbon atoms represented by the formula include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, and isopentyl group.
Specific examples of the monomer represented by the above formula (IV) include N-vinylformamide, N-methyl-N-vinylformamide, N-vinylacetamide, N-methyl-N-vinylacetamide and the like.
[0018]
Specific examples of N-vinyl pyrrolidone monomers include N-vinyl-2-pyrrolidone, N-vinyl-3-propyl-2-pyrrolidone, N-vinyl-5,5-dimethyl-2-pyrrolidone, N-vinyl. -3,5-dimethyl-2-pyrrolidone and the like can be mentioned. Specific examples of N-vinylcaprolactam monomers include N-vinyl-2-caprolactam and N-vinyl-3-propyl-2-caprolactam.
[0019]
Among the N-vinylamide monomers, the monomer represented by the above formula (IV) and N-vinyl-2-caprolactam are preferable from the viewpoint of safety of the monomer to the human body, and are easily available. Preferred from the point of view are N-vinylformamide, N-vinylacetamide, N-methyl-N-vinylacetamide and N-vinyl-2-caprolactam, and form stability of water-soluble film and fiber softener in water-soluble film N-vinyl-2-caprolactam and N-vinylacetamide are preferable from the viewpoint of the solubility of the packaged product.
[0020]
The oxyalkylene monomer that can be used in the present invention is specifically an unsaturated monomer having an oxyalkylene group, and examples thereof include polyoxyethylene (meth) allyl ether, polyoxypropylene ( (Meth) allyl ether, polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, polyoxyethylene (meth) acrylamide, polyoxypropylene (meth) acrylamide, polyoxyethylene (1- (meth) acrylamide-1, 1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropylene vinyl ether, and the like.
[0021]
Specific examples of vinyl ether monomers include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, ethylene glycol vinyl ether, 1,3-propanediol vinyl ether, 1,4- Examples include butanediol vinyl ether.
[0022]
As a method for producing a PVA containing a nonionic monomer unit, a vinyl ester polymer obtained by copolymerizing a vinyl ester monomer and a nonionic monomer is used as an alcohol or dimethyl sulfoxide. Examples include saponification in a solution.
[0023]
Examples of the vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valelate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate and vinyl versatate. Among these, vinyl acetate is preferable from the viewpoint of industrially obtaining PVA.
[0024]
In the present invention, as long as the PVA is within a range that does not impair the effects of the present invention, other than the vinyl alcohol unit, the vinyl ester monomer unit, and the nonionic monomer unit described above in the main chain of the molecule. The monomer unit may be contained. Examples of such monomer units include α-olefins such as ethylene, propylene and 1-hexene; acrylamide derivatives such as acrylamide and N-methylacrylamide; methacrylamide derivatives such as methacrylamide and N-methylmethacrylamide; Acetyl; allyl ethers such as propyl allyl ether; vinyl silanes such as vinyl trimethoxysilane; isopropenyl acetate; 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, 7- Α-olefins containing a hydroxy group such as octen-1-ol, 3-methyl-3-buten-1-ol; ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, 2-acrylamido-2-methylpropane Sulfur derived from sulfonic acid Monomers having a phonic acid group; vinyloxyethyl trimethylammonium chloride, vinyloxybutyl trimethylammonium chloride, vinyloxyethyl dimethylamine, vinyloxymethyldiethylamine, N-acrylamidomethyltrimethylammonium chloride, N-acrylamidoethyltrimethylammonium chloride, Examples thereof include monomer units obtained by copolymerizing a monomer having a cationic group derived from N-acrylamidodimethylamine, allyltrimethylammonium chloride, methallyltrimethylammonium chloride, dimethylallylamine, allylethylamine and the like. The content of these monomer units varies depending on the purpose and application used, but is usually 5 mol% or less, preferably 2 mol% or less.
[0025]
Examples of the copolymerization method of the vinyl ester monomer and the nonionic monomer described above include known methods such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method. Among them, a bulk polymerization method that polymerizes without solvent or a solution polymerization method that polymerizes in a solvent such as alcohol is usually employed. Examples of the alcohol used as a solvent during solution polymerization include lower alcohols such as methanol, ethanol, and propanol. Examples of the initiator used for copolymerization include azo initiators such as 2,2′-azobis (isobutyronitrile) and 2,2′-azobis (2,4-dimethylvaleronitrile), and benzoyl peroxide. And known initiators such as peroxide initiators such as n-propyl peroxycarbonate. Although there is no restriction | limiting in particular about superposition | polymerization temperature, The range of 0 to 150 degreeC is suitable.
[0026]
In the present invention, PVA is usually obtained by copolymerizing a vinyl ester polymer obtained by copolymerizing the above vinyl ester monomer and a nonionic monomer with an alcohol such as methanol or an ester such as methyl acetate. An alkali catalyst such as potassium hydroxide or sodium hydroxide, sulfuric acid, hydrochloric acid, p-toluenesulfonic acid, etc. in one or more solvents selected from dimethyl sulfoxide, etc., preferably in a lower alcohol solvent such as methanol It can obtain by saponifying using the acid catalyst of this. The conditions for the saponification reaction are appropriately adjusted depending on the structure of the vinyl ester polymer and the degree of saponification of the desired vinyl alcohol polymer. Usually, the saponification reaction is carried out using a molar ratio of the catalyst and the vinyl ester monomer. The (catalyst / vinyl ester monomer) is in the range of 0.001 to 5.0, and the reaction is carried out at a reaction temperature of 20 to 180 ° C. for a reaction time of 0.1 to 20. As the saponification method, a known method such as a batch method or a continuous method can be applied.
[0027]
In general, a water-soluble film is required to have strength and toughness so that it can withstand use in a hot and humid region or a cold region, and particularly needs to have impact resistance at a low temperature. For the purpose of improving the impact resistance at low temperatures, various plasticizers can be blended with the water-soluble film of the present invention in order to lower the glass transition point of the water-soluble film. Furthermore, a plasticizer can also be blended for the purpose of improving solubility in water and processability.
[0028]
The plasticizer that can be blended in the water-soluble film of the present invention is not particularly limited as long as it is generally used as a plasticizer for PVA. For example, glycerin, diglycerin, diethylene glycol, triethylene glycol, propylene Polyhydric alcohols such as glycol, dipropylene glycol, trimethylolpropane, pentaerythritol and 1,3-butanediol; polyethers such as polyethylene glycol and polypropylene glycol; polyvinylamides such as polyvinylpyrrolidone; bisphenol A and bisphenol S Phenol derivatives such as N-methylpyrrolidone, dimethylacetamide and other amide compounds; glycerin, pentaerythritol, sorbitol and other polyhydric alcohols such as ethylene oxide And compounds and water was added, and these may be used alone or in combination. Among these plasticizers, glycerin, diglycerin, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, trimethylolpropane, polyethylene glycol, and polyvinylpyrrolidone are used for the purpose of improving the water solubility of the water-soluble film. It is particularly preferable to use glycerin, diglycerin, trimethylolpropane, polyethylene glycol, or polyvinylpyrrolidone from the viewpoint of suppressing the decrease in water solubility of the water-soluble film due to bleeding out of the plasticizer.
[0029]
The molecular weight of polyethylene glycol in the case of using polyethylene glycol as a plasticizer is not particularly limited, but the number average molecular weight is 100 to 100 from the viewpoint of compatibility with PVA and the effect of suppressing the decrease in water solubility of the water-soluble film due to bleeding out. 1000 is preferable. Although there is no restriction | limiting in particular also about the molecular weight of polyvinylpyrrolidone, It is preferable that it is 1000-20000 in a weight average molecular weight from a compatible point with PVA.
[0030]
The compounding quantity of a plasticizer is 1-50 weight part with respect to 100 weight part of PVA, and 1-35 weight part is further more preferable. When the blending amount of the plasticizer is less than 1 part by weight, the effect of blending the plasticizer may not be manifested. On the other hand, when the compounding amount of the plasticizer exceeds 50 parts by weight, the bleedout of the plasticizer becomes large, and the blocking resistance of the obtained water-soluble film may be lowered. If the plasticizer in the water-soluble film is transferred to the contents of the package, the water solubility of the water-soluble film may decrease over time, or the flexibility at low temperatures may decrease. In order to avoid such a situation, the blending amount of the plasticizer is preferably 1 to 20 parts by weight with respect to 100 parts by weight of PVA.
[0031]
As the blending amount of the plasticizer increases, the heat-sealing temperature of the water-soluble film decreases, and the productivity at the time of bag-making the water-soluble film tends to be improved. From such a viewpoint, it is preferable to blend the plasticizer at a ratio such that the heat-sealing temperature of the resulting water-soluble film is 170 ° C. or lower, and it is preferable to blend the plasticizer at a ratio so as to be 160 ° C. or lower. Further preferred.
[0032]
The compounding amount of the plasticizer tends to affect the strength and Young's modulus of the resulting water-soluble film, but from the practical point of view of the water-soluble film, the strength of the film is 0.5 kg / mm.²Preferably, it is 0.8 kg / mm²The above is more preferable. The Young's modulus of the water-soluble film is 0.5 kg / mm from the viewpoint of the form stability of the resulting water-soluble film and the processability of the bag making machine.²Preferably, it is 1.0 kg / mm²More preferably, a plasticizer is preferably blended so that a water-soluble film having a Young's modulus in such a range can be obtained.
[0033]
In the water-soluble film of the present invention, saccharides can be blended as necessary, whereby the solubility of the water-soluble film in water and the form stability can be further enhanced. Examples of the saccharide include monosaccharides such as glucose, chain sugar alcohols such as oligosaccharides, polysaccharides, and mannitol. Examples of the polysaccharide include starch, cellulose, chitin, chitosan, hemicellulose, pectin, pullulan, agar, alginic acid, carrageenan, dextrin, and trehalose, and one or more of these can be used. Examples of the chain sugar alcohol include tetrites having 4 carbon atoms such as trait and erythrite, pentites having 5 carbon atoms such as arabit and xylit, and hexits having 6 carbon atoms such as glycit, mannitol and sorbit. From the viewpoint of good solubility of the water-soluble film in cold water, starch is particularly preferable among saccharides. As the starch, for example, raw starch such as corn and potato, and processed starch obtained by subjecting these to physical or chemical treatment (dextrin, oxidized starch, etherified starch, cationized starch, etc.) can be used.
[0034]
The blending amount of the saccharide is 1 to 30 parts by weight with respect to 100 parts by weight of PVA from the viewpoint of the form stability of the water-soluble film and the cold water solubility of the packaging body in which the fiber softener is packaged with the water-soluble film. The amount is preferably 1 to 20 parts by weight, more preferably 1 to 10 parts by weight. If the amount of the saccharide is less than 1 part by weight, the effect of improving the form stability of the water-soluble film and the solubility of the package in cold water may not be exhibited. On the other hand, when the amount of the saccharide is more than 30 parts by weight, the solubility in water may be lowered, particularly when the package is dissolved with a small amount of water (at a high cation concentration), which is not preferable.
[0035]
If necessary, the water-soluble film of the present invention can further contain an inorganic filler. Examples of inorganic fillers that can be used include silica, heavy, light or surface-treated calcium carbonate, aluminum hydroxide, aluminum oxide, titanium oxide, diatomaceous earth, barium sulfate, calcium sulfate, zeolite, zinc oxide, silicic acid, Examples include silicates, mica, magnesium carbonate, kaolin, halosite, pyroferrite, sericite, and other clays, talc, and the like, and one or more of these can be used. Among these, silica and talc are preferably used particularly from the viewpoint of dispersibility in PVA. The average particle diameter of the inorganic filler is preferably 1 μm or more from the viewpoint of blocking prevention of the water-soluble film, and is preferably 10 μm or less from the viewpoint of dispersibility in PVA. In order to satisfy both the anti-blocking property of the water-soluble film expressed by blending the inorganic filler and the required performance of the dispersibility of the inorganic filler in PVA, an inorganic having an average particle size of about 1 to 7 μm It is more preferable to use a filler.
[0036]
The blending amount of the inorganic filler is preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of PVA from the viewpoint of anti-blocking of the water-soluble film and dispersibility of the inorganic filler in PVA. The amount is more preferably 15 parts by weight, and particularly preferably 1 to 10 parts by weight. In addition, when it mixes exceeding 20 weight part of inorganic fillers, the dispersibility to PVA will fall, an inorganic filler will aggregate, and there exists a tendency for the water solubility of the water-soluble film obtained to fall.
[0037]
In the water-soluble film of the present invention, additives such as a colorant, a fragrance, an extender, an antifoaming agent, a release agent, an ultraviolet absorber, and a surfactant may be appropriately blended as necessary. In particular, in order to improve the releasability between the metal surface such as a die or drum of the film forming apparatus and the formed film or film stock solution, the ratio of 0.01 to 5 parts by weight of the surfactant with respect to 100 parts by weight of PVA It is preferable to mix with. In addition, the water-soluble film of the present invention, if necessary, within a range that does not impair the effects of the present invention, a type of PVA different from the PVA used in the present invention, carboxymethylcellulose, polyacrylamide, polyacrylic acid or A water-soluble polymer such as a salt thereof, methyl cellulose, or hydroxymethyl cellulose may be blended. In particular, from the viewpoint of improving the water solubility of the film, it is preferable to add a low viscosity type carboxymethylcellulose.
[0038]
In producing the water-soluble film of the present invention, the production raw material is blended with the above PVA, if necessary, with a plasticizer, saccharides, inorganic filler and other components, and dissolved in a solvent in a stirring tank or It can prepare by mixing by a well-known method, such as the method to disperse | distribute and the method of melt-kneading in an extruder.
[0039]
The water-soluble film of the present invention is a film-forming method generally used when forming a film, for example, a casting film-forming method, a wet film-forming method, a dry film-forming method, an extrusion film-forming method, a melt film-forming method. It can be manufactured by a film forming method such as a method, a coating method or an inflation film forming method. For example, the components necessary for the production of the water-soluble film of the present invention include one or more solvents such as water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, methanol, n-propanol, i-propanol, and phenol. After being dissolved in the mixed solution to prepare a uniform film-forming stock solution, it can be produced by a film-forming method such as a casting film-forming method. The concentration of the film-forming stock solution is preferably 70% by weight or less (the solvent content is 30% by weight or more) from the viewpoint of viscosity.
[0040]
The water-soluble film of the present invention preferably has a thickness of 10 to 200 μm, and more preferably 20 to 150 μm from the viewpoint of the balance between film strength and water solubility.
[0041]
In order to improve the anti-blocking property of the water-soluble film of the present invention, the surface of the water-soluble film is roll-mated as necessary, or a powder for preventing blocking such as silica or starch is applied to the water-soluble film. Or embossing. Roll matting of the film surface can be performed by forming fine irregularities on the roll that comes into contact with the film before drying during film formation. The embossing treatment can be generally performed by nipping between an embossing roll and a rubber roll while applying heat and pressure after the film is formed. The application of powder has a large anti-blocking effect, but since it may not be used depending on the application, it is preferable to prevent blocking by applying a roll mat or embossing treatment. It is particularly preferable to form a roll mat.
[0042]
The water-soluble film of the present invention has an excellent dissolution rate in cold water, and the complete dissolution time in 5 ° C. water (film thickness 40 μm) is preferably 80 seconds or less, more preferably 60 seconds or less. Especially preferably, it is 40 seconds or less. The complete dissolution time in 5 ° C. water as used herein is a value measured by the slide mount method. That is, it is a value obtained by measuring a time until a film is completely dissolved by cutting a 40 μm-thick film into a 40 × 40 mm square, sandwiching it in a slide mount, and immersing it in 5 ° C. water under stirring. . The complete dissolution time when the film thickness is different from 40 μm is a value obtained by converting the film thickness to 40 μm by the following formula (V).
Dissolution time (seconds) = (40 / film thickness (μm))²X Dissolution time (seconds) ... (V)
[0043]
The water-soluble film of the present invention is characterized by excellent cold water solubility when a fiber softener is packaged to form a package. After packaging the fiber softener, the package that was allowed to stand at room temperature for 10 minutes was cut into a 40 × 40 mm square, and this was measured by the slide mount method. The complete dissolution time in 5 ° C. water (film thickness 40 μm) is , Preferably 120 seconds or less, more preferably 100 seconds or less, and particularly preferably 80 seconds or less.
[0044]
In addition, the water-soluble film of the present invention is also characterized in that the solubility hardly deteriorates with time even when the fiber softener is packaged and stored for a long time. As an accelerated test for long-term storage, a package in which a fiber softener is wrapped with a water-soluble film is placed in a thermostatic chamber at 30 ° C. and 80% RH, taken out after 2 weeks, and the dissolution time of the film is measured by the method described above. To do. The quotient (B / A) of the dissolution time (A) after leaving the packaging body in which the fiber softener is packaged for 10 minutes at room temperature and the dissolution time (B) after the storage acceleration test is preferably 3.0 or less, 2.0 or less is more preferable, 1.5 or less is more preferable, and 1.20 or less is particularly preferable.
[0045]
In order to wrap a fiber softener using the water-soluble film of the present invention, a method generally employed for film-wrapping an article can be employed, and there is no particular limitation. As a method of packaging the fabric softener, heat-sealing the film after packaging the fabric softener using a three-side seal automatic packaging machine, etc., or bonding the peripheral edge of the film with an adhesive, and opening the resulting bag Examples thereof include a method of heat-sealing or bonding the open portion after filling the fabric softener from the portion.
[0046]
The packaged body in which the fabric softener is packaged with the water-soluble film of the present invention is excellent in solubility in cold water, and the solid content after drying undissolved matter remaining in the washing machine after use in a commercially available washing machine is: The amount is preferably 1.0 g or less, more preferably 0.5 g or less, and particularly preferably 0.3 g or less.
[0047]
There is no restriction | limiting in particular about the kind of fiber softening agent which can be packaged with the water-soluble film of this invention, What is used daily at a general household as a fiber softening agent is mentioned. Specific examples thereof include quaternary ammonium salts such as di (hardened beef tallow alkyl) dimethylammonium chloride, methyl di (hardened beef tallow alkyl) amine (Japanese Patent Laid-Open No. 52-579965), acylated alkanolamine (Japanese Patent Laid-Open No. 58-60070). However, it is not necessarily limited to these. The water-soluble film of the present invention is suitable for packaging a cationic surfactant because it has the property that the solubility in water does not decrease even when the cationic surfactant is packaged.
[0048]
The fiber softener used for packaging preferably has a moisture content of 10% by weight or less, more preferably 8% by weight or less, and particularly preferably 5% by weight or less. When the moisture content of the fiber softener exceeds 10% by weight, the plasticizer in the water-soluble film moves to the fiber softener side when packaged with a water-soluble film, and the plasticizer in the water-soluble film decreases. And the solubility of the package in water may be reduced. For the fabric softener, if necessary, solvents such as ethyl alcohol, isopropyl alcohol, propylene glycol, polyhydric alcohol, nonionic surfactants, water-soluble salts such as ammonium chloride, fragrances, colorants, antifoaming agents, An anti-redeposition agent, a fluorescent brightening agent, a bactericidal agent, a shrinking agent, a silicone compound, an inorganic electrolyte, an antibacterial agent, an antioxidant, a preservative, and the like may be blended.
[0049]
The form which the fiber softener can take is solid, powder, granule, liquid, etc., and there is no restriction in particular. A typical form of the fabric softener is a dispersion containing a di-long chain alkyl quaternary ammonium salt as a main component, but may be a powder or a tablet as disclosed in JP-A-6-306769. .
[0050]
In the package of the present invention, the filling ratio of the fiber softener is preferably 60 to 98%, and more preferably 70 to 95%. If the filling factor of the fabric softener in the package is too small, the package will contain a lot of air, so it will be difficult to sink in water when the package is placed in the washing machine, and the dissolution time will be Tend to be longer. For these reasons, the filling factor of the fiber softener is preferably 60% or more. When the filling ratio of the fiber softener exceeds 98%, the package body sinks too quickly in water, and the package body tends to remain at the bottom of the washing machine and the solubility in water tends to be reduced.
[0051]
Usually, the fabric softener is added at the time of final rinsing, but as a method to save labor, a separate drawer is provided in the washing machine, and when the laundry starts, a package containing the fiber softener is put in this drawer. It is recommended to use a structure in which the package body flows down into the washing machine tub by the action of water used for rinsing. When a package containing a fabric softener is applied to a washing machine having such a structure, since the amount of water that normally flows in the drawer is less than the amount of water in the washing tub, the package is made with a small amount of water. Needs to dissolve and flow down into the tank. In this case, if the amount of air is adjusted by changing the filling rate of the fabric softener in the package, when the water flows into the drawer, the package is appropriately floated by the buoyancy of the air, Since the lower part comes into contact with water, the package is dissolved even with a small amount of water, and the package does not remain in the drawer in a state where it does not dissolve in water.
[0052]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In the following examples and comparative examples, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified. In Examples and Comparative Examples, measurement and evaluation of various properties of films were performed by the following methods.
[0053]
[Method for Measuring Film Solubility (1)]
A magnetic stirrer was installed in a constant temperature bath at 5 ° C. A 1 liter glass beaker containing 1 liter of distilled water was placed in the thermostatic bath and stirred at 330 rpm using a 5 cm rotor. After the distilled water in the beaker reached 5 ° C., water solubility measurement was started.
Cut the film into 4cm x 4cm squares, put them on a slide mount, immerse them in 5 ° C stirring water, observe the dissolution state of the film, and the time until the film is completely dissolved (in seconds) Was measured. When the film thickness was different from 40 μm, the film thickness was converted to a value of 40 μm according to the following formula (V).
[0054]
Dissolution time (seconds) = (40 / film thickness (μm))²X Dissolution time (seconds) ... (V)
[0055]
[Method for Measuring Film Solubility (2)]
A 4.5cm x 4.5cm bag is made from the film, and 7 g of a mixed solution of saphanol P-200 (manufactured by Sanyo Chemical Co., Ltd.) and hexylene glycol (weight ratio is 1: 1) is placed inside as a fiber softener. Sealed and sealed to produce a package. Ten minutes after packaging, the package was cut into 4 cm × 4 cm and evaluated for water solubility at 5 ° C.
[0056]
[Method for evaluating storage stability of film]
A 4.5cm x 4.5cm bag is made from the film, and 7 g of a mixed solution of saphanol P-200 (manufactured by Sanyo Chemical) and hexylene glycol (weight ratio is 1: 1) is placed inside as a fiber softener and heat sealed. And sealed to produce a package. As an accelerated test for long-term storage, this packaging bag was placed in a constant temperature and humidity chamber at 30 ° C. and 80% RH, taken out after 2 weeks, and the water solubility of the packaged film was measured according to the method described above.
The storage stability of the film is a quotient (B / A) of the dissolution time (A) after standing for 10 minutes at room temperature and the dissolution time (B) after the storage acceleration test using a package in which a fiber softener is packaged. ) And evaluated by the magnitude of the value.
[0057]
[Method for evaluating solubility of package]
A 4.5cm x 4.5cm bag is made from the film, and 7 g of a mixed solution of saphanol P-200 (manufactured by Sanyo Chemical) and hexylene glycol (weight ratio is 1: 1) is placed inside as a fiber softener and heat sealed. And sealed to produce a package. Using a commercially available washing machine (Drum type dry washing machine made by Sharp), put the package in a drawer dedicated to fabric softener and drive the washing machine. After washing, collect the residue in the drawer at 105 ° C. The weight after drying for 6 hours was measured and evaluated.
[0058]
[Measurement method of Young's modulus and strength]
A film having a width of 10 mm was conditioned for one week under an atmosphere of 20 ° C. and 65% RH, and then a tensile test was performed by an autograph. The chuck interval was 50 mm and the pulling speed was 500 mm / min.
[0059]
Synthesis Example 1 (Synthesis of modified PVA)
A 5 L reactor equipped with a stirrer, reflux condenser, nitrogen inlet tube and thermometer was charged with 1100 g of vinyl acetate monomer, 1852.4 g of methanol, and 53.7 g of a 30% methanol solution of N-vinyl-2-caprolactam. Charged and degassed by bubbling nitrogen gas for 30 minutes. The temperature of the reactor was increased, and when the internal temperature reached 60 ° C., 3.5 g of 2,2′-azobis (isobutyronitrile) was added to initiate polymerization. Polymerization was carried out while successively adding a 30% methanol solution of N-vinyl-2-caprolactam so that the molar ratio with the vinyl acetate monomer was constant, and after 4.5 hours, the polymerization was stopped. The solid concentration at this time was 45%. Next, unreacted vinyl acetate monomer was removed while adding methanol occasionally under reduced pressure at 30 ° C. to obtain a methanol solution of polyvinyl acetate copolymer (concentration 38%). Next, a methanol solution of a polyvinyl acetate copolymer adjusted to a concentration of 35% by adding methanol to a methanol solution of 0.004 in an alkali molar ratio (number of moles of NaOH / number of moles of vinyl acetate monomer units) of 0.004 (10% concentration) was added to carry out the saponification reaction. The degree of saponification of the obtained PVA (PVA-1) was 82.1 mol%.
[0060]
10 g of methanol was added to 1 g of the obtained PVA, heated to 60 ° C. to swell the PVA, 5 g of NaOH methanol solution (10% concentration) was added, and the mixture was stirred at 60 ° C. for 3 hours, extracted with methanol Soxhlet Was carried out for 3 days and then dried to obtain a purified product of PVA. The modified amount of the N-vinyl-2-caprolactam monomer unit determined from proton NMR measurement of the purified PVA product was 2.0 mol%. Further, the average degree of polymerization of the PVA was measured according to a conventional method JIS K6726, and was 500.
[0061]
Modified PVA (PVA-2 to 11, PVA-2 and 11), except that the polymerization conditions and saponification conditions were changed so that the type and modification amount of the comonomer, the polymerization degree and the saponification degree of PVA were as shown in Table 1 below. PVA-14-22) were synthesized. The contents of the synthesized modified PVA are shown in Table 1 below.
[0062]
Synthesis Example 2 (Unmodified PVA)
A 5 L reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet tube and a thermometer was charged with 900 g of vinyl acetate monomer and 2100 g of methanol, and degassed by bubbling nitrogen gas for 30 minutes. The temperature of the reactor was increased, and when the internal temperature reached 60 ° C., 1.0 g of 2,2′-azobis (isobutyronitrile) was added to initiate polymerization. After 5 hours, the polymerization was stopped by cooling. The solid concentration at this time was 45%. Subsequently, unreacted vinyl acetate monomer was removed while adding methanol occasionally under reduced pressure at 30 ° C. to obtain a methanol solution of polyvinyl acetate (concentration 38%). Next, a methanol solution of a polyvinyl acetate copolymer adjusted to a concentration of 35% by adding methanol to a methanol solution of 0.004 in an alkali molar ratio (number of moles of NaOH / number of moles of vinyl acetate monomer units) of 0.004 (10% concentration) was added to carry out the saponification reaction. The degree of saponification of the obtained PVA (PVA-12) was 80.5 mol%.
[0063]
10 g of methanol was added to 1 g of the obtained PVA, heated to 60 ° C. to swell the PVA, 5 g of NaOH methanol solution (10% concentration) was added, and the mixture was stirred at 60 ° C. for 3 hours, extracted with methanol Soxhlet Was carried out for 3 days and then dried to obtain a purified product of PVA. It was 500 when the average degree of polymerization of this PVA was measured according to JIS K6726 of the usual method.
[0064]
Non-modified PVA (PVA-13, 23 and 24) was synthesized in the same manner as PVA-12 except that the polymerization conditions and saponification conditions were changed. The contents of the synthesized unmodified PVA are shown in Table 1 below.
[0065]
Example 1
To 100 parts by weight of PVA (PVA-1) shown in Table 1, 15 parts by weight of glycerin and water are added as a plasticizer to create a uniform 5% aqueous solution (water content 90%) and flow on a polyester film. After stretching and drying at room temperature, a film having a thickness of 40 μm was obtained by peeling from the polyester film. The obtained film was heat-treated at 100 ° C. for 10 minutes. When the water solubility of this film was measured, the complete dissolution time in 5 ° C. water was 33 seconds. In addition, the Young's modulus was measured by adjusting the humidity to 20 ° C. and 65% RH as an index of handleability such as process passability typified by the waist of the film, and 0.8 kg / mm.²The strength is 1.7kg / mm²Met.
When the solubility of the film after packaging the fiber softener was evaluated, the complete time in 5 ° C. water of the film 10 minutes after packaging the fiber softener was 68 seconds. The complete time in 5 ° C. water of the film when put in a constant temperature and humidity chamber of 30 ° C. and 80% RH and taken out after 2 weeks is 69 seconds, and the change with time of the solubility is 1.0. There was no decrease in solubility.
When the solubility of the packaging body in which the fiber softener was packaged was evaluated, the dry weight of the residue from the washing machine drawer was 0.01 g.
[0066]
  Example 25 and Reference Examples 1-11
  A film in the same manner as in Example 1 except that the contents of PVA, the types and blending amounts of plasticizers and saccharides, and the filling rate of the fabric softener into the package are changed as shown in Tables 1 and 2 below. Were prepared and subjected to various evaluations. The evaluation results are shown in Table 3 below.
[0067]
Comparative Examples 1-10
A film was produced in the same manner as in Example 1 except that the content of PVA was changed as shown in Table 1 below, and various evaluations were performed. The evaluation results are shown in Table 3 below.
[0068]
[Table 1]

[0069]
[Table 2]

[0070]
[Table 3]

[0071]
From the results of Table 3 above, the water-soluble film of the present invention produced using PVA-1 to 13 has excellent solubility in cold water, and excellent practical properties such as strength and Young's modulus. I understand that. Furthermore, it turns out that the water-soluble film of the present invention is suitable for a fiber softener packaging film because the solubility hardly decreases even when the fiber softener is packaged and stored for a long time.
A film composed of a modified PVA in which the nonionic monomer unit exceeds 10 mol% has low strength and Young's modulus (Comparative Example 1). A film made of PVA having a vinyl alcohol unit exceeding 90 mol% has poor solubility of the film when the fiber softener is packaged, and when the package is used in a washing machine, the undissolved residue remains in the drawer dedicated to the softener. Many (Comparative Examples 2, 6, 7, 10). A film made of nonionic group-modified PVA having a vinyl alcohol unit smaller than 75 mol% has low strength and Young's modulus (Comparative Example 3), and a film made of unmodified PVA having a vinyl alcohol unit smaller than 75 mol% Storage stability when the softener is packaged is low (Comparative Example 11). Degree of polymerization (P) is {(X-93)²A film made of PVA larger than × 16/3 + 300} has poor solubility of the film when the fiber softener is packaged (Comparative Example 4). A film made of PVA having a polymerization degree (P) smaller than {100 × Z + 100} has a poor film strength (Comparative Example 5). The film made of ionic group-modified PVA not only has poor solubility of the film when the fiber softener is packaged, but also decreases in solubility over time (Comparative Examples 8 and 9).
[0072]
【The invention's effect】
The water-soluble film of the present invention has excellent solubility in cold water, and not only has high solubility especially when a fiber softener is packaged, but also stored for a long time in a state in which the fiber softener is packaged. Even in this case, since the solubility is difficult to decrease, it is preferably used as a film for packaging a fabric softener.

Claims (4)

The fiber softener contains a vinyl alcohol unit, a vinyl ester monomer unit and an N-vinyl caprolactam monomer unit in the main chain of the molecule, and the following formulas (I), (II ′) and (III Wrapped with a water-soluble film made of a vinyl alcohol polymer satisfying
75 ≦ X ≦ 90 (I)
0.1 ≦ Z ≦ 10 (II ′)
100 × Z + 100 ≦ P ≦ (X−93) ² × 16/3 + 300 (III)
X: Content of vinyl alcohol unit (mol%)
Z: Content of N-vinylcaprolactam monomer unit (mol%)
P: Degree of polymerization of vinyl alcohol polymer The package according to claim 1, wherein the N-vinylcaprolactam monomer unit is an N-vinyl-2-caprolactam unit.   The package according to claim 1 or 2, wherein a filling factor of the fiber softener in the package is 60% to 98%. The package according to any one of claims 1 to 3, wherein the form of the fiber softener is solid, powder, granule or liquid.