JP4279573B2 - Agricultural multilayer film - Google Patents

Description

（１）
【００２１】
ここで、式（１）中、Ｒ１〜Ｒ５はそれぞれ独立して水素原子又は炭素数１〜１０のアルキル基を表す。より好ましくは、Ｒ １は炭素数６〜１０のアルキル基、特に好ましくは、炭素数６〜８のアルキル基であり、Ｒ２〜Ｒ５は水素原子又は炭素数１〜２のアルキル基、特に好ましくは、水素原子又はメチル基である。
【００２２】
上記式（１）で表されるトリアリールトリアジン系紫外線吸収剤の入手方法は特に限定されず、市販のものを使用することができる。例えば、チバ・スペシャリティーケミカルズ社製ＴＩＮＵＶＩＮ １５７７Ｆやサイテック社製ＵＶ１１６４等を挙げることが出来る。
【００２３】
本発明における農業用多層フィルムは、求める効果に影響を与えない範囲で、その他の紫外線吸収剤を併用することが出来る。併用可能な紫外線吸収剤としては、例えば、２，４−ジヒドロキシベンゾフェノン、２−ヒドロキシ−４−メトキシベンゾフェノン、２−ヒドロキシ−４−オクトキシベンゾフェノン、５，５’−メチレンビス（２−ヒドロキシ−４−メトキシベンゾフェノン）等の２−ヒドロキシベンゾフェノン類；フェニルサリシレート、レゾルシノールモノベンゾエート、２，４−ジ第三ブチルフェニル−３’，５’−ジ第三ブチル−４’−ヒドロキシベンゾエート、２，４−ジ第三アミルフェニル−３’，５’−ジ第三ブチル−４’−ヒドロキシベンゾエート、ヘキサデシル−３，５−ジ第三ブチル−４−ヒドロキシベンゾエート等のベンゾエート類；２−エチル−２’−エトキシオキザニリド、２−エトキシ−４’−ドデシルオキザニリド等の置換オキザニリド類；エチル−α−シアノ−β，β−ジフェニルアクリレート、メチル−２−シアノ−３−メチル−３−（ｐ−メトキシフェニル）アクリレート等のシアノアクリレート類等があげられる。また、酸化亜鉛、酸化セリウム等の無機酸化物系紫外線吸収剤も挙げられる。これらの紫外線吸収剤は、一種又は二種以上で用いられる。
【００２４】
本発明の農業用多層フィルム中の、ベンゾトリアゾール系紫外線吸収剤、及びトリアジン系紫外線吸収剤の含有量は、各々、全フィルム対し２重量％未満、好ましくは０．１〜１．５重量％、更に好ましくは０．２〜１重量％である。含有量が上記範囲未満では紫外線遮蔽効果が低く、上記範囲を超えると一般的な農業用フィルムである農業用フィルムに適応した場合、ブリードアウトによる白化等で問題がある。
これらの紫外線吸収剤は両者を含有した農業用フィルムにおいて、２００ｎｍ〜３７０ｎｍの領域の紫外線を実質完全に遮蔽する量以上添加されることが好ましい。
【００２５】
本発明の好ましい態様としては、中間層の単位体積当たりの樹脂組成物に対する紫外線吸収剤（２種以上の合計）含有率（重量％）をＸ、内層中の単位体積当たりの紫外線吸収剤含有率（重量％）をＹ、外層中の単位体積当たりの紫外線吸収剤含有率（重量％）をＺとしたとき、Ｘ＞Ｙ、かつＸ＞Ｚであると、長期にわたり紫外線吸収能を保持できる効果が顕著であることが判明した。
特に本願発明の特定の２種類の紫外線吸収剤を用いてこの層構成にすると、単独の各紫外線吸収剤を同様の層構成にした場合や、他の紫外線吸収剤の２種の組み合わせで同様の層構成にした場合に比べても、顕著な効果を有する。
ここで、Ｙ及びＺはＹ＝Ｚであっても、異なっていてもよい。また、特に好ましい態様としては、Ｙ＝Ｚ＝０である場合が挙げられる。
具体的には、中間層中の樹脂組成物に対する紫外線吸収剤含有率であるＸとしては、０．１〜３．０重量％、好ましくは０．１５〜２．０重量％、更に好ましくは０．２〜１．０重量％の範囲が挙げられる。ＹおよびＺとしては、０〜２．０重量％、好ましくは０または、０．００１〜０．５重量％の範囲が挙げられる。
更に本発明の好ましい態様としては、少なくとも外層、中間層、内層を有する３層以上の積層構造を有する農業用多層フィルムであって、外層および内層（表面層）には紫外線吸収剤を配合せず、中間層に紫外線吸収剤を配合してなることを特徴とする農業用多層フィルムが挙げられる。
【００２６】
本発明の農業用多層フィルムは、全層厚み０．３ｍｍ以下の少なくとも３層以上を有する多層フィルムの少なくとも一層にその構成成分としてＳｉ，Ａｌ，Ｍｇ，Ｃａ，Ｌｉから選ばれた少なくとも１つの原子を含有する無機化合物をフィルム全層中に３％含有することを特徴とする。使用できる無機化合物として、例えば赤外線吸収剤（保温剤）や充填剤を挙げることが出来る。
【００２７】
赤外線吸収剤（保温剤）は、赤外線吸収能を有する無機微粒子であり、これらは一種又は二種以上で組み合わせて用いることができる。用いることの出来る無機微粒子は特に制限はないが、成 分：Ｓｉ ，Ａｌ ，Ｍｇ ，Ｃａ,Ｌｉ から選ばれた少なくとも１つの原子を含有する無機化合物である。例えば、酸化マグネシウム、酸化カルシウム、酸化アルミニウム、酸化珪素、水酸化リチウム、水酸化マグネシウム、水酸化カルシウム、水酸化アルミニウム、炭酸マグネシウム、炭酸カルシウム、硫酸カルシウム、硫酸マグネシウム、硫酸アルミニウム、燐酸リチウム、燐酸カルシウム、珪酸マグネシウム、珪酸カルシウム、珪酸アルミニウム、アルミン酸カルシウム、アルミン酸マグネシウム、アルミノ珪酸ナトリウム、アルミノ珪酸カリウム、アルミノ珪酸カルシウム、カオリン、クレー、タルク、マイカ、ゼオライト、ハイドロタルサイト類化合物、リチウム・アルミニウム複合水酸化物、アルミニウム・リチウム・マグネシウム複合炭酸塩化合物、アルミニウム・リチウム・マグネシウム複合珪酸塩化合物、マグネシウム・アルミニウム・珪素複合水酸化物、マグネシウム・アルミニウム・珪素複合硫酸塩化合物、マグネシウム・アルミニウム・珪素複合炭酸塩化合物、複数種アニオンを含有する金属複合水酸化物塩等が挙げられる。これらは結晶水を脱水したものであってもよい。
【００２８】
上記赤外線吸収剤（保温剤）として用いる無機微粒子は天然物であってもよく、また合成品であってもよい。また、上記無機微粒子は、その結晶構造、結晶粒子径などに制限されることなく使用することが可能である。
【００２９】
また、上記赤外線吸収剤（保温剤）として用いる無機微粒子は、その表面をステアリン酸のごとき高級脂肪酸、オレイン酸アルカリ金属塩のごとき高級脂肪酸金属塩、ドデシルベンゼンスルホン酸アルカリ金属塩のごとき有機スルホン酸金属塩、高級脂肪酸アミド、高級脂肪酸エステルまたはワックスなどで被覆したものも使用できる。
【００３０】
上記赤外線吸収剤（保温剤）として用いる無機微粒子は、単独または２種以上組み合わせて使用することが出来る。その平均粒子径は好ましくは、０．０５〜１５μｍ、より好ましくは０．１〜１０μｍの範囲である。無機微粒子の平均粒子径が上記範囲より小さいと、樹脂中での分散性が劣りブツ（無機物の２次凝集物）が生成してフィルム外観が悪化すると共に、樹脂との混練時の粉立ちが激しくハンドリング性が劣る。逆に、無機微粒子の平均粒子径が上記範囲より大きいと、透明性で劣ったり押出し機ブレーカースクリーン部で目詰まりが生じ、生産性が悪化する。
【００３１】
また、充てん剤としては、フイルムのベタツキを抑制するために、あるいは保温性をさらに高めるために、例えばシリカ、タルク、水酸化アルミニウム、ハイドロタルサイト、硫酸カルシウム、ケイ酸カルシウム、水酸化カルシウム、水酸化マグネシウム、カオリンクレー、マイカ、アルミナ、炭酸マグネシウム、アルミン酸ナトリウム、導電性酸化亜鉛、リン酸リチウムなどが用いられる。これらの充てん剤は１種用いてもよいし、２種以上を組み合わせて用いてもよい。
【００３２】
これら無機化合物の使用量は、フィルム全層中に、３〜３０重量％、より好ましくは３〜２０重量％、更に好ましくは３〜１５重量％である。３重量％未満では、本発明の効果を充分に発揮することはできず、３０重量％を超える範囲では農業用フィルムとしての透明性及び機械的強度が劣る上、経済的に不利である。
【００３３】
本発明において用いられる農業用多層フィルムには耐候剤としてヒンダードアミン化合物を多層フィルム中の少なくとも１層に添加することが出来る。また、このヒンダードアミン化合物は、一種又は二種以上組み合わせて用いることができる。ヒンダードアミン化合物は、もちろん全層に同じ種類を含有させてもよいが、例えば最内層と最外層（ハウス外面）にブリードアウトしにくい高分子量タイプ含有させ、その他の層には農業用として通常配合されるヒンダードアミン化合物を含有させることもできる。また、これら高分子量ヒンダードアミン化合物は、エチレンやその他モノマーとの共重合タイプ（例えばエチレン・環状アミノビニル化合物共重合体）でも構わないし、ポリエチレンを始めとするポリマーにグラフト付加させたものでも構わない。その場合、例えば同一の層にエチレン・環状アミノビニル化合物共重合体と農業用として通常配合されるヒンダードアミン系光安定剤を含有させることもできる。
【００３４】
使用可能な農業用として通常配合されるヒンダードアミン系光耐候剤は、分子中にピペリジン環構造を少なくとも２個以上有しかつ分子量が５００以上のヒンダードアミン化合物（以下、「ピペリジン環含有ヒンダードアミン化合物」ともいう）が好ましい。ここで、上記ピペリジン環含有ヒンダードアミン化合物のピペリジン環の数が２個未満では十分な耐候性が得られず、また、分子量が５００未満では揮発しやすくなり、長期の耐候性を得ることができない。また、上記ピペリジン環含有ヒンダードアミン化合物のピペリジン環の数は２〜５０個であることが好ましく、また、分子量は７５０以上であることが好ましい。
【００３５】
上記ピペリジン環含有ヒンダードアミン化合物としては、例えば、ビス（１，２，２，６，６−ペンタメチル−４−ピペリジル）−２−ブチル−２−（３，５−ジ第三ブチル−４−ヒドロキシベンジル）マロネート、テトラ（２，２，６，６−テトラメチル−４−ピペリジル）ブタンテトラカルボキシレート、テトラ（１，２，２，６，６−ペンタメチル−４−ピペリジル）ブタンテトラカルボキシレート、ビス（２，２，６，６−テトラメチル−４−ピペリジル）・ジ（トリデシル）ブタンテトラカルボキシレート、ビス（１，２，２，６，６−ペンタメチル−４−ピペリジル）・ジ（トリデシル）ブタンテトラカルボキシレート、３，９−ビス〔１，１−ジメチル−２−｛トリス（２，２，６，６−テトラメチル−４−ピペリジルオキシカルボニルオキシ）ブチルカルボニルオキシ｝エチル〕−２，４，８，１０−テトラオキサスピロ〔５．５〕ウンデカン、３，９−ビス〔１，１−ジメチル−２−｛トリス（１，２，２，６，６−ペンタメチル−４−ピペリジルオキシカルボニルオキシ）ブチルカルボニルオキシ｝エチル〕−２，４，８，１０−テトラオキサスピロ〔５．５〕ウンデカン、１，５，８，１２−テトラキス〔４，６−ビス｛Ｎ−（２，２，６，６−テトラメチル−４−ピペリジル）ブチルアミノ｝−１，３，５−トリアジン−２−イル〕−１，５，８，１２−テトラアザドデカン、１−（２−ヒドロキシエチル）−２，２，６，６−テトラメチル−４−ピペリジノール／コハク酸ジメチル縮合物、２−第三オクチルアミノ−４，６−ジクロロ−ｓ−トリアジン／Ｎ，Ｎ’−ビス（２，２，６，６−テトラメチル−４−ピペリジル）ヘキサメチレンジアミン縮合物、Ｎ，Ｎ’−ビス（２，２，６，６−テトラメチル−４−ピペリジル）ヘキサメチレンジアミン／ジブロモエタン縮合物などがあげられる。使用可能な市販のヒンダードアミン系化合物を例示すれば、ＴＩＮＵＶＩＮ７７０、ＴＩＮＵＶＩＮ７８０、ＴＩＮＵＶＩＮ１４４、ＴＩＮＵＶＩＮ６２２ＬＤ、ＴＩＮＵＶＩＮ ＮＯＲ ３７１、ＣＨＩＭＡＳＳＯＲＢ１１９ＦＬ、ＣＨＩＭＡＳＳＯＲＢ９４４（以上、チバガイギー社製）、サノールＬＳ−７６５（三共（株）製）、ＭＡＲＫ ＬＡ−６３、ＭＡＲＫ ＬＡ−６８、ＭＡＲＫ ＬＡ−６８、ＭＡＲＫ ＬＡ−６２、ＭＡＲＫ ＬＡ−６７、ＭＡＲＫ ＬＡ−５７、ＬＡ−９００（以上、旭電化（株）製）、ＵＶ−３３４６、ＵＶ−３５２９、ＵＶ−３５８１、ＵＶ−３８５３（以上、サイテック社製）、ホスタビンＮ２０、ホスタビンＮ２４、ホスタビンＮ３０、ホスタビン８４５、サンデュボアＰＲ−３１、ナイロスタッブＳ−ＥＥＤ（以上、クラリアント・ジャパン社製）等が挙げられる。これらのピペリジン環含有ヒンダードアミン化合物は、一種又は二種以上で用いられる。
【００３６】
また、本発明の熱可塑性樹脂フィルム中には、通常合成樹脂に使用される各種添加剤を併用することができる。それらの添加剤としては、例えば、金属の有機酸塩、塩基性有機酸塩および過塩基性有機酸塩、ハイドロタルサイト化合物、エポキシ化合物、β−ジケトン化合物、多価アルコール、ハロゲン酸素酸塩、硫黄系、フェノール系およびホスファイト系などの酸化防止剤、熱安定剤、滑剤、帯電防止剤、着色剤、アンチブロッキング剤、防曇剤、防霧剤などがあげられる。
【００３７】
上記の金属の有機酸塩、塩基性有機酸塩および過塩基性有機酸塩を構成する金属種としては、Ｌｉ，Ｎａ，Ｋ，Ｃａ，Ｂａ，Ｍｇ，Ｓｒ，Ｚｎ，Ｃｄ，Ｓｎ,Ｃｓ，Ａｌ，有機Ｓｎがあげられ、有機酸としては、カルボン酸、有機リン酸類またはフェノール類があげられ、該カルボン酸としては、例えば、酢酸、プロピオン酸、酪酸、吉草酸、カプロン酸、エナント酸、カプリル酸、ネオデカン酸、２−エチルヘキシル酸、ペラルゴン酸、カプリン酸、ウンデカン酸、ラウリン酸、トリデカン酸、ミリスチン酸、パルミチン酸、イソステアリン酸、ステアリン酸、12−ヒドロキシステアリン酸、ベヘニン酸、モンタン酸、エライジン酸、オレイン酸、リノール酸、リノレン酸、チオグリコール酸、メルカプトプロピオン酸、オクチルメルカプトプロピオン酸、安息香酸、モノクロル安息香酸、ｐ−第三ブチル安息香酸、ジメチルヒドロキシ安息香酸、３，５−ジ第三ブチル−４−ヒドロキシ安息香酸、トルイル酸、ジメチル安息香酸、エチル安息香酸、クミン酸、ｎ−プロピル安息香酸、アセトキシ安息香酸、サリチル酸、ｐ−第三オクチルサリチル酸等の一価カルボン酸、シュウ酸、マロン酸、コハク酸、グルタル酸、アジピン酸、ピメリン酸、スベリン酸、アゼライン酸、セバチン酸、マレイン酸、フマール酸、シトラコン酸、メタコン酸、イタコン酸、アコニット酸、チオジプロピオン酸、フタル酸、イソフタル酸、テレフタル酸、オキシフタル酸、クロルフタル酸等の二価のカルボン酸あるいはこれらのモノエステル又はモノアマイド化合物、ブタントリカルボン酸、ブタンテトラカルボン酸、ヘミメリット酸、トリメリット酸、メロファン酸、ピロメリット酸等の三価又は四価カルボン酸のジ又はトリエステル化合物などがあげられ、また該有機リン酸類としては、モノまたはジオクチルリン酸、モノまたはジドデシルリン酸、モノまたはジオクタデシルリン酸、モノまたはジ−（ノニルフェニル）リン酸、ホスホン酸ノニルフェニルエステル、ホスホン酸ステアリルエステルなどがあげられ、また該フェノール類としては、フェノール、クレゾール、キシレノール、メチルプロピルフェノール、メチル第三オクチルフェノール、エチルフェノール、イソプロピルフェノール、第三ブチルフェノール、ｎ−ブチルフェノール、ジイソブチルフェノール、イソアミルフェノール、ジアミルフェノール、イソヘキシルフェノール、オクチルフェノール、イソオクチルフェノール、２−エチルヘキシルフェノール、第三オクチルフェノール、ノニルフェノール、ジノニルフェノール、第三ノニルフェノール、デシルフェノール、ドデシルフェノール、オクタデシルフェノール、シクロヘキシルフェノール、フェニルフェノールフェノール、クレゾール、エチルフェノール、シクロヘキシルフェノール、ノニルフェノール、ドデシルフェノールなどがあげられる。
【００３８】
上記防曇剤については特に制限はないが、公知の種々の非イオン系界面活性剤、アニオン系界面活性剤、カチオン系界面活性剤等を始めとする、多価アルコールと高級脂肪酸類とから成る多価アルコール部分エステル系のものが好適である。このような防曇剤の具体例としては、例えば非イオン系界面活性剤、例えばソルビタンモノステアレート、ソルビタンモノミリステート、ソルビタンモノパルミテート、ソルビタンモノベヘネート、ソルビタンとアルキレングリコールの縮合物と脂肪酸とのエステルなどのソルビタン系界面活性剤やグリセリンモノパルミテート、グリセリンモノステアレート、グリセリンモノラウレート、ジグリセリンモノパルミテート、グリセリンジパルミテート、グリセリンジステアレート、ジグリセリンモノパルミテート・モノステアレート、トリグリセリンモノステアレート、トリグリセリンジステアレートあるいはこれらのアルキレンオキシド付加物等などのグリセリン系界面活性剤やポリエチレングリコールモノステアレート、ポリエチレングリコールモノパルミテート、ポリエチレングリコールアルキルフェニルエーテルなどのポリエチレングリコール系界面活性剤やその他トリメチロールプロパンモノステアレートなどのトリメチロールプロパン系界面活性剤やペンタエリスリトールモノパルミテート、ペンタエリスリトールモノステアレートなどのペンタエリスリトール系界面活性剤、アルキルフェノールのアルキレンオキシド付加物；ソルビタン／グリセリンの縮合物と脂肪酸とのエステル、ソルビタン／アルキレングリコールの縮合物と脂肪酸とのエステル；ジグリセリンジオレートナトリウムラウリルサルフェート、ドデシルベンゼンスルホン酸ナトリウム、セチルトリメチルアンモニウムクロライド、ドデシルアミン塩酸塩、ラウリン酸ラウリルアミドエチルリン酸塩、トリエチルセチルアンモニウムイオダイド、オレイルアミノジエチルアミン塩酸塩、ドデシルピリジニウム塩などやそれらの異性体を含むものなどを挙げることができる。
【００３９】
上記防霧剤としては、例えばフッ素系界面活性剤やシリコーン系界面活性剤が挙げられ、フッ素系界面活性剤の具体例としては、通常の界面活性剤の疎水基のＣに結合したＨの代わりにその一部または全部をＦで置換した界面活性剤で、特にパーフルオロアルキル基またはパーフルオロアルケニル基を含有する界面活性剤である。以上の各種添加剤は、それぞれ１種または２種以上を組み合わせて使用することができる。パーフルオロアルキル基を有する含フッ素化合物としては、例えば、アニオン系含フッ素界面活性剤、カチオン系含フッ素界面活性剤、両性含フッ素界面活性剤、ノニオン系含フッ素界面活性剤、含フッ素オリゴマーなどがあげられる。
【００４０】
上記パーフルオロアルキル基を有する含フッ素化合物の使用量は、熱可塑性樹脂１００重量部に対し、好ましくは０．００１〜１０重量部、更に好ましくは０．０１〜５重量部である。該含フッ素化合物の使用量が０．００１重量部未満では防霧性効果がほとんど発揮されず、１０重量部を超えても効果が飽和されるため好ましくない。
【００４１】
上記フェノール系酸化防止剤としては、例えば、２，６−ジ第三ブチル−ｐ−クレゾール、２，６−ジフェニル−４−オクタデシロキシフェノール、ステアリル（３，５−ジ第三ブチル−４−ヒドロキシフェニル）−プロピオネート、ジステアリル（３，５−ジ第三ブチル−４−ヒドロキシベンジル）ホスホネート、チオジエチレングリコールビス〔（３，５−ジ第三ブチル−４−ヒドロキシフェニル）プロピオネート〕、１，６−ヘキサメチレンビス〔（３，５−ジ第三ブチル−４−ヒドロキシフェニル）プロピオネート〕、１，６−ヘキサメチレンビス〔（３，５−ジ第三ブチル−４−ヒドロキシフェニル）プロピオン酸アミド〕、４，４’−チオビス（６−第三ブチル−ｍ−クレゾール) 、２，２’−メチレンビス（４−メチル−６−第三ブチルフェノール）、２，２’−メチレンビス（４−エチル−６−第三ブチルフェノール）、ビス〔３，３−ビス（４−ヒドロキシ−３−第三ブチルフェニル）ブチリックアシッド〕グリコールエステル、４，４’−ブチリデンビス（６−第三ブチル−ｍ−クレゾール）、２，２’−エチリデンビス（４，６−ジ第三ブチルフェノール）、２，２’−エチリデンビス（４−第二ブチル−６−第三ブチルフェノール) 、１，１，３−トリス（２−メチル−４−ヒドロキシ−５−第三ブチルフェニル）ブタン、ビス〔２−第三ブチル−４−メチル−６−（２−ヒドロキシ−３−第三ブチル−５−メチルベンジル）フェニル〕テレフタレート、１，３，５−トリス（２，６−ジメチル−３−ヒドロキシ−４−第三ブチルベンジル）イソシアヌレート、１，３，５−トリス（３，５−ジ第三ブチル−４−ヒドルキシベンジル）イソシアヌレート、１，３，５−トリス（３，５−ジ第三ブチル−４−ヒドロキシベンジル）−２，４，６−トリメチルベンゼン、１，３，５−トリス〔（３，５−ジ第三ブチル−４−ヒドロキシフェニル）プロピオニルオキシエチル〕イソシアヌレート、テトラキス〔メチレン−３−（３，５−ジ第三ブチル−４−ヒドロキシフェニル）プロピオネート〕メタン、２−第三ブチル−４−メチル−６−（２−アクリロイルオキシ−３−第三ブチル−５−メチルベンジル) フェノール、３，９−ビス〔１，１−ジメチル−２−｛（３−第三ブチル−４−ヒドロキシ−５−メチルフェニル）プロピオニルオキシ｝エチル〕−２，４，８，１０−テトラオキサスピロ〔５. ５〕ウンデカン、トリエチレングリコールビス〔（３−第三ブチル−４−ヒドロキシ−５−メチルフェニル）プロピオネート〕、ｎ−オクタデシル３−（３’，５’−ジ−ｔ−ブチル−４’−ヒドロキシフェニル）プロピオネート、テトラキス［３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオニルオキシメチル］メタン等があげられる。
【００４２】
上記硫黄系酸化防止剤としては、例えば、チオジプロピオン酸ジラウリル、ジミリスチル、ジステアリル等のジアルキルチオジプロピオネート類及びペンタエリスリトールテトラ（β−ドデシルメルカプトプロピオネート）等のポリオールのβ−アルキルメルカプトプロピオン酸エステル類があげられる。
【００４３】
上記ホスファイト系酸化防止剤としては、例えば、トリスノニルフェニルホスファイト、トリス（２，４−ジ第三ブチルフェニル）ホスファイト、トリス〔２−第三ブチル−４−（３−第三ブチル−４−ヒドロキシ−５−メチルフェニルチオ）−５−メチルフェニル〕ホスファイト、トリデシルホスファイト、オクチルジフェニルホスファイト、ジ（デシル）モノフェニルホスファイト、モノデシルジフェニルホスファイト、モノ（ジノニルフェニル）ビス（ノニルフェニル）ホスファイト、ジ（トリデシル）ペンタエリスリトールジホスファイト、ジステアリルペンタエリスリトールジホスファイト、ジ (ノニルフェニル）ペンタエリスリトールジホスファイト、ビス（２，４−ジ第三ブチルフェニル）ペンタエリスリトールジホスファイト、ビス（２，６−ジ第三ブチル−４−メチルフェニル）ペンタエリスリトールジホスファイト、テトラ（トリデシル）イソプロピリデンジフェノールジホスファイト、テトラ（トリデシル）イソプロピリデンジフェノールジホスファイト、テトラ（Ｃ 12-15 混合アルキル）−４，４’−ｎ−ブチリデンビス（２−第三ブチル−５−メチルフェノール) ジホスファイト、ヘキサ（トリデシル）−１，１，３−トリス（２−メチル−４−ヒドロキシ−５−第三ブチルフェニル）ブタントリホスファイト、テトラキス（２，４−ジ第三ブチルフェニル）ビフェニレンジホスホナイト、２，２’−メチレンビス（４，６−ジ第三ブチルフェニル）( オクチル) ホスファイト、テトラキス（２，４−ジ−ｔ−ブチルフェニル）４，４’−ビフェニレン−ジ−ホスホナイト、２，２−メチレンビス（４，６−ジ−ｔ−ブチルフェニル）オクチルホスファイト等があげられる。
【００４４】
上記着色剤としては例えば、フタロシアニンブルー、フタロシアニングリーン、ハンザイエロー、アリザリンレーキ、酸化チタン、亜鉛華、群青、パーマネントレッド、キナクリドン、カーボンブラック等を挙げることができる。
【００４５】
アンチブロッキング剤としては、珪藻土、合成シリカ、タルク、マイカ、ゼオライト等が挙げられる。これらアンチブロッキング剤は単独で、または２種以上を組み合わせて用いることができ、通常０．０１〜０．５重量％の範囲が好ましい。
【００４６】
本発明の熱可塑性樹脂フィルムは、上述した成分が組合わされて含有してなり、更に本発明の熱可塑性樹脂フィルムに含有することができる下記の任意成分を、必要に応じて含有させることができる。任意成分とは、その他安定剤、耐衝撃性改善剤、架橋剤、充填剤、発泡剤、帯電防止剤、造核剤、プレートアウト防止剤、表面処理剤、難燃剤、螢光剤、防黴剤、殺菌剤、金属不活性剤、離型剤、顔料、加工助剤などを挙げることができる。
【００４７】
本発明の熱可塑性樹脂フィルムは、各種添加剤を配合するには、各々必要量秤量し、リボンブレンダー、バンバリーミキサー、ヘンシェルミキサー、スーパーミキサー、単軸又は二軸押出機、ロールなどの配合機や混練機その他従来から知られている配合機、混合機を使用すればよい。このようにして得られた樹脂組成物をフィルム化するには、それ自体公知の方法、例えば、溶融押出し成形法（Ｔダイ法、インフレーション法を含む）、カレンダー加工、ロール加工、押出成型加工、ブロー成型、インフレーション成型、溶融流延法、加圧成型加工、ペースト加工、粉体成型等の方法を好適に使用することができる。
【００４８】
本発明の熱可塑性樹脂フィルム厚みについては、強度やコストの点で０．０３〜０．３ｍｍの範囲のものが好ましく、０．０５〜０．２ｍｍのものがより好ましい。この範囲未満では強度的に問題があり、この範囲を超えると成形が困難になる。
【００４９】
本発明において基材層にポリオレフィン系樹脂を用いる場合、前記ポリオレフィン系基材の最内層に接して防曇性被膜を形成することができる。
本発明における防曇塗膜としては既に公知の農業用フィルムに用いることができる防曇塗膜を適応することが出来る。好ましくは無機コロイド物質と親水性有機化合物を主成分とした防曇塗膜や無機コロイド物質とアクリル系樹脂を主成分とする防曇塗膜を用いることができる。
【００５０】
本発明において用いることができる無機コロイド物質と親水性有機化合物を主成分とする防曇塗膜として、例えば、特公昭６３−４５４３２号、特公昭６３−４５７１７号、特公昭６４−２１５８号、特許第３０９４２９６号等に示されている化合物を挙げることができる。
【００５１】
本発明においてはアクリル系樹脂及び無機質コロイドゾルを主成分とする防曇性被膜も好適に用いることができる。
アクリル系樹脂として好ましく用いられる１つの例としては、少なくとも合計６０重量％のアクリル酸またはメタクリル酸のアルキルエステル類からなる単量体、またはアクリル酸またはメタクリル酸のアルキルエステル類とアルケニルベンゼン類との単量体混合物及び０〜４０重量％の共重合しうるα、β−エチレン性不飽和単量体とを、通常の重合条件に従って、例えば乳化剤の存在下に、水系媒質中で乳化重合させて得られる水分散性の重合体または共重合体である疎水性アクリル系樹脂を挙げることができる。
本発明で用いるアクリル系樹脂は、疎水性アクリル系樹脂であることが好ましく、即ち、上記のようなアクリル酸又はメタクリル酸のアルキルエステル類、又は、アクリル酸又はメタクリル酸のアルキルエステル類とアルケニルベンゼン類との単量体混合物を、少なくとも計６０重量％を含有すること、好ましくは８０重量％以上含有することが好ましい。６０重量％に満たないときは、形成被膜の耐水性が十分でないために、防曇持続性能を発揮しえないことがあり好ましくない。
本発明のアクリル系樹脂は、特に、ガラス転移温度が３５〜８０℃のものを用いるのが好ましい。ガラス転移温度が低すぎると無機質コロイド粒子が数次凝集して不均一な分散状態をとりやすく、高すぎる場合、透明性のある均一な被膜を得るのが困難となりやすい。
【００５２】
本発明において、基体フィルムの表面に形成させる被膜の厚さは、基体フィルムの１／１０以下を目安に選択するとよいが、必ずしもこの範囲に限定されるものではない。被膜の厚さが基体フィルムの１／１０より大であると、基体フィルムと被膜とでは屈曲性に差があるため、被膜が基体フィルムから剥離する等の現象がおこりやすく、また、被膜に亀裂が生じて基体フィルムの強度を低下させるという現象が生起し、好ましくない。
【００５３】
また、基体フィルムと被膜組成物に由来する被膜との接着性が充分でない場合には、基体フィルムに表面処理を施しておいてもよい。本発明の積層フィルムの表面に施す処理の方法としては、コロナ放電処理、スパッタエッチング処理、ナトリウム処理、サンドブラスト処理等の方法が挙げられる。コロナ放電処理法は、針状あるいはナイフエッジ電極と対極間で放電を行わせ、その間に試料を入れて処理を行い、フィルム表面にアルデヒド、酸、アルコールパーオキサイド、ケトン、エーテル等の酸素を含む官能基を生成させる処理である。スパッタエッチング処理は、低気圧グロー放電を行っている電極間に試料を入れ、グロー放電によって生じた正イオンの衝撃によりフィルム上に多数の微細な突起を形成するものである。サンドブラスト処理は、フィルム面に微細な砂を吹きつけて、表面上に多数の微細な凹凸を形成するものである。これら表面処理の中では、塗布層との密着性、作業性、安全性、コスト等の点から、コロナ放電処理が好適である。
【００５４】
本発明に係る農業用熱可塑性樹脂フィルムを、実際に使用するにあたっては、防曇被膜の設けられた側をハウス又はトンネルの内側となるようにして展張するのがよい。
このようにして得られた本願発明の農業用多層フィルムは、２００ｎｍ〜３７０ｎｍの紫外線を実質完全に遮蔽することができる。「実質完全に遮蔽」とは、未使用の農業用フィルムの状態で、その光線の透過率が０〜２％以下であることを意味する。
【００５５】
【実施例】
以下、本発明を実施例、比較例に基づいてさらに詳細に説明するが、本発明はその要旨を越えない限り、以下の例に限定されるものではない。
【００５６】
（１）積層フィルムの調整（防曇剤練り込みタイプ、防曇塗膜塗布タイプ共に）３層インフレーション成形装置として３層ダイに１００ｍｍφ（（株）プラ工研製）を用い、押出機はチューブ外内層を３０ｍｍφ（（株）プラ技研製）２台、中間層を４０ｍｍφ（（株）プラ技研製）として、外内層押出し機温度１８０℃、中間層押し出し機温度１７０℃、ダイス温度１８０〜１９０℃、ブロー比２．０〜３．０、引取り速度３〜７ｍ／分、厚さ０．１５ｍｍにて表−２〜表−７に示した成分からなる３層の積層フィルムを得た。なお、これらのフィルムは、ハウス展張時にチューブの端部を切り開いて使用するため、展開した際に製膜時のチューブ外層が展張時にはハウスの内層（内面）となる。
【００５７】
〔配合〕 添加量は各表記載通り。
ＨＰ−ＬＤＰＥ：高圧ラジカル法触媒で製造した分岐状ポリエチレン（ＭＦＲ：１．１ｇ／１０分、密度０．９２０）日本ポリケム製ノバテックＬＤ「ＹＦ３０」
メタロセンＰＥ：メタロセン触媒で製造したエチレン・αオレフィン共重合体（ＭＦＲ：２ｇ／１０分、密度０．９０７）日本ポリケム製カーネル「ＫＦ２７０」
ＥＶＡ▲１▼ ：エチレン・酢酸ビニル共重合体（酢酸ビニル含有量５重量％、ＭＦＲ２ｇ／１０分）
ＥＶＡ▲２▼ ：エチレン・酢酸ビニル共重合体（酢酸ビニル含有量１５重量％、ＭＦＲ２ｇ／１０分）
キマソーブ９４４：チバ・スペシャルティ・ケミカルズ社製光安定剤
エチレン・環状アミノビニル共重合体：日本ポリケム（株）製「ノバテックＬＤ・ＸＪ１００Ｈ」ＭＦＲ＝３ｇ／１０分（１９０℃、ＪＩＳ−Ｋ６７６０） 密度＝０．９３１ｇ／ｃｍ３（ＪＩＳ−Ｋ６７６０）環状アミノビニル化合物含量＝５．１重量％（０．７モル％）孤立して存在する環状アミノビニル化合物の割合＝９０モル％ 融点＝１１１℃
トリアリールトリアジンン系紫外線吸収剤Ａ：Ｒ１がオクチル基、Ｒ２〜Ｒ ５がメチル基であるトリアリールトリアジン化合物
トリアリールトリアジンン系紫外線吸収剤Ｂ：Ｒ１がヘキシル基、Ｒ２〜Ｒ ５が水素原子であるトリアリールトリアジン化合物
ベンゾトリアゾール系紫外線吸収剤Ａ：チバ・スペシャリティーケミカルズ社製ＴＩＮＵＶＩＮ ３２６
ベンゾトリアゾール系紫外線吸収剤Ｂ：チバ・スペシャリティーケミカルズ社製ＴＩＮＵＶＩＮ ３２７
ベンゾフェノン系紫外線吸収剤Ａ：サイテック社製サイアソーブＵＶ−５３１
ベンゾフェノン系紫外線吸収剤Ｂ：サイテック社製サイアソーブＵＶ−９
【００５８】
（２）フィルムの表面処理
得られたチューブ状フィルムの外層表面を、放電電圧１２０Ｖ、放電電流４．７Ａ、ラインスピード１０ｍ／ｍｉｎでコロナ放電処理を行い、ＪＩＳ−Ｋ６７６８による「濡れ指数」を測定し、その値を確認した。
【００５９】
（３）防曇性塗膜の形成（防曇塗膜塗布タイプ）
表−１に示した主成分（シリカゾル及び／又はアルミナゾル）と熱可塑性樹脂と架橋剤及び液状分散媒とを配合して防曇剤組成物を得た。
防曇剤組成物配合は以下の配合とした。
無機質コロイドゾル（コロイダルシリカ） ４．０
熱可塑性樹脂（サンモールＳＷ−１３１） ３．０
架橋剤（Ｔ．Ａ．Ｚ．Ｍ） ０．１
分散媒（水／エタノール＝３／１） ９３
（注）無機質コロイドゾルの配合量は、無機質粒子量で示し熱可塑性樹脂の配合量は重合体固形分量で示す。
コロイダルシリカ：日産化学社製スノーテックス３０、平均粒子径１５ｍμ
サンモールＳＷ−１３１：三洋化成社製アクリルエマルジョン
Ｔ．Ａ．Ｚ．Ｍ：相互薬工社製アジリジン系化合物
（２）で表面処理した基体フィルムの表面に、上記の防曇剤組成物を＃５バーコーターを用いて各々塗布した。塗布したフィルムを８０℃のオーブン中に１分間保持して、液状分散媒を揮発させ防曇性塗膜を形成した。得られた各フィルムの塗膜の厚みは約１μｍであった。
【００６０】
今回、防曇性塗膜を設けたタイプ（フィルム厚１５０μｍ）を用いて試験を行ったが、防曇剤を練り混んだタイプでも同様の効果が得られる。また、今回用いた樹脂、添加剤以外の組み合わせ、又は今回と異なるフィルム厚みでも、その要旨を変えない限り、同様の効果が得られる。今回用いた各々のサンプルについて次のような光学特性測定を行った。実施例及び比較例における各測定法を以下に示す。
【００６１】
▲１▼透明性
上記、愛知県海部郡の圃場に構築したパイプハウスに、３層インフレーション成形により得られた積層フィルム（防曇塗膜を塗布するタイプの場合、ハウス内層側表面に防曇性塗膜を形成（塗工）後）を密閉状態になるように展張した。平成１１年８月下旬〜平成１４年１１月下旬に渡り、上記パイプハウスに展張中のフィルムの一部をサンプリングし、その透明性（波長５５５ｎｍにおける直進光線透過率）を分光光度計（日立製作所製、Ｕ３５００型）により測定し、その値を示した。
【００６２】
▲２▼紫外線吸収能保持性
上記、愛知県海部郡の圃場に構築したパイプハウスに、３層インフレーション成形により得られた積層フィルム（防曇塗膜を塗布するタイプの場合、ハウス内層側表面に防曇性塗膜を形成（塗工）後）を密閉状態になるように展張した。平成１１年８月下旬〜平成１４年１１月下旬に渡り、上記パイプハウスに展張中のフィルムの一部をサンプリングし、その紫外線吸収能（波長３２５ｎｍにおける全光線透過率）を分光光度計（日立製作所製、Ｕ３５００型）により測定し、その値を示した。
【００６３】
〔実施例１〜６〕紫外線吸収剤としてトリアジン系紫外線吸収剤及びベンゾトリアゾール系紫外線吸収剤を無機フィラーと組み合わせて用いた上記配合により、フィルム厚１５０μｍ、層比１／３／１の三層フィルム（防曇塗膜塗布タイプ）を作成し、前記方法により初期透明性、透明性経時変化、初期紫外線吸収能、紫外線吸収能経時変化等の測定を行い、各フィルムの評価を行なった。その結果を〔表１〕〔表２〕に示す。
【表１】

【表２】

【００６４】
〔比較例１〜５〕紫外線吸収剤としてトリアジン系紫外線吸収剤及びベンゾトリアゾール系紫外線吸収剤を用い無機フィラーを組み合わせない配合、更にトリアジン系紫外線吸収剤のみを用いた上記配合により、フィルム厚１５０μｍ、層比１／３／１の三層フィルム（防曇塗膜塗布タイプ）を作成し、前記方法により初期透明性、透明性経時変化、初期紫外線吸収能、紫外線吸収能経時変化等の測定を行い、各フィルムの評価を行なった。その結果を〔表３〕に示す。
【表３】

【００６５】
〔比較例６〜９〕紫外線吸収剤としてベンゾトリアゾール系紫外線吸収剤のみを無機フィラーと組み合わせて用いた上記配合により、フィルム厚１５０μｍ、層比１／３／１の三層フィルム（防曇塗膜塗布タイプ）を作成し、前記方法により初期透明性、透明性経時変化、初期紫外線吸収能、紫外線吸収能経時変化等の測定を行い、各フィルムの評価を行なった。その結果を〔表４〕に示す。
【表４】

【００６６】
〔比較例１０〜１４〕紫外線吸収剤としてベンゾフェノン系紫外線吸収剤を無機フィラーと組み合わせて用いた上記配合により、フィルム厚１５０μｍ、層比１／３／１の三層フィルム（防曇塗膜塗布タイプ）を作成し、前記方法により初期透明性、透明性経時変化、初期紫外線吸収能、紫外線吸収能経時変化等の測定を行い、各フィルムの評価を行なった。その結果を〔表５〕に示す。
【表５】

【００６７】
以上の結果から明らかなように、トリアジン系紫外線吸収剤及びベンゾトリアゾール系紫外線吸収剤を無機フィラーと組み合わせてフィルム中に添加すると広い紫外線吸収域と良好な紫外線吸収能保持性を付与できることがわかる。更に、多層フィルムの表面層以外（ハウス内層、ハウス外層以外：中間層とする）に紫外線吸収剤を添加、もしくは中間層中の単位体積当たりの紫外線吸収剤含有率Ｘ＞内層中の単位体積当たりの紫外線吸収剤含有率Ｙ、かつＸ＞外層中の単位体積当たりの紫外線吸収剤含有率Ｚとなるように添加した場合、長期にわたり紫外線吸収能を保持できる効果が顕著であることが判明した。これら広い紫外線吸収波長域を有し、かつ紫外線吸収能の長期保持性に優れた農業用多層フィルムは、長期間にわたりハウス内環境において病害菌やカビの繁殖抑制、害虫防除性及び内張資材の劣化防止性等にも優れ、農業用多層フィルム基材劣化の原因である紫外線を長期に渡り吸収するためフィルム寿命を伸ばすことが出来る上、塗膜密着性の低下原因となるブリードアウトを抑制する為、長期に渡り良好な塗膜密着性を得ることが出来る。
【００６８】
これに対し、本発明以外の添加方法を用いた場合（比較例１〜１４）には、紫外線吸収能の保持性等に欠けるか、もしくは、紫外線吸収域を付与できず、長期間使用した場合に、ハウス内環境において病害菌やカビの繁殖抑制、害虫防除性及び内張資材の劣化防止性等を得ることは難しい。つまり、紫外線カットフィルムとしての性能を維持することは難しく、製品の性質上非常に問題がある。
【００６９】
つまり、本発明の添加方法を用いなければ、農業用途のような過酷な条件下で広い紫外線吸収波長域を有しながら、長期にわたり紫外線吸収能を保持することは難しく、更に特定の添加方法を用いることによりブリードアウトを抑制しつつ、非常に良好な紫外線吸収能を保持できることから、防曇塗膜を塗布するタイプのフィルムにも適応可能である。よって、農業用フィルムに適応する場合、構成要件である本発明の特定の紫外線吸収剤及び無機フィラー（及び特定の添加方法）が必須であり、この添加方法に寄らなければ、紫外線吸収能の長期保持性は維持できない。
【発明の効果】
本発明の農業用多層フィルムは、紫外線吸収剤が樹脂表面にブリードアウトしにくいため、紫外線遮蔽性（吸収波長域が広い）に優れ、かつその性能が長期間使用した場合にも維持され、ハウス内環境において病害菌やカビの繁殖抑制、害虫防除性及び内張資材の劣化防止性等にも優れ、しかも長期に渡り塗膜密着性、耐候性が損なわれず、農業用フィルムとして好適に用いることができる。また、該フィルムに防曇塗膜を設けた場合には、ブリードアウトが抑えられ該基材との接着性が低下しないので好ましい。本発明のポリオレフィン系樹脂組成物を用いたフィルムは、透明でも、梨地でも、半梨地でもよく、ハウス、トンネル、マルチング用、袋掛用等の農業用フィルム（いわゆる農ビ、農ポリ、農サクビ、農ＰＯ、硬質フィルム等）の用途に好適に使用することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an agricultural multilayer film in which a decrease in ultraviolet absorption capacity due to bleed-out, etc. is suppressed when processed into a film or sheet. More specifically, when the film is used for a long period of time, it has excellent ultraviolet shielding properties. In particular, the present invention relates to a multilayer film for agriculture that is excellent in suppressing the propagation of pests and fungi, pest control, deterioration prevention of lining materials, etc. in the house environment.
[Prior art]
[0002]
Agricultural houses have become larger year by year, and the film expansion work for covering the houses with films has become more labor-intensive. On the other hand, the number of farmers is declining year by year and aging is progressing, and it is not easy to secure manpower for annual expansion work. In view of such a situation, the film to be spread in the house is a film that is easy to stretch and has a long use period until re-covering as much as possible, in other words, has a long life of 2 years or more and can maintain the initial performance over a long period of time. There is a need to develop high performance agricultural films.
[0003]
Among these coating materials, agricultural polyolefin-based resin films mainly composed of polyolefin-based resins are lighter in density because they are smaller than vinyl chloride resin, and generate little toxic gas even when incinerated. Wide film that does not require adhesive processing for splicing can be provided at a low cost, and has been actively used.
[0004]
On the other hand, a method of adding a small amount of an ultraviolet absorber to an agricultural film to cut a part of the ultraviolet ray to prevent the deterioration of the agricultural film is now known, but today, it is further in the ultraviolet region (200 nm to 370 nm). Attempts have been made to reduce pesticide cultivation by creating UV-cutting films that cut all UV rays substantially completely, and controlling the growth and control of pests and fungi in the house environment.
[0005]
In a relatively thin agricultural film having a total film thickness of 0.3 mm or less, it is necessary to contain an ultraviolet absorber at a relatively high concentration in order to completely cut ultraviolet rays. However, these agricultural UV-cut films cannot maintain the initial UV-cutting properties for a long time, and many films that actually transmit a part of the wavelength region where the UV-blocking effect can be expected are transmitted. It was expected.
[0006]
Conventionally UV absorbers blended in polyolefin resin materials have been mainly nickel compounds, but in recent years, UV absorbers such as benzophenone, benzotriazole, and triazine have been developed and deployed in various applications. Has been.
[0007]
Each of these ultraviolet absorbers has an absorption wavelength region peculiar to its structure, and its compatibility with the equipment resin differs depending on its structure, molecular weight and the like. Various attempts have been made to widen the absorption range of ultraviolet rays and improve the retention of ultraviolet absorption ability, but no agricultural film having both of them has been obtained.
[0008]
Accordingly, an object of the present invention is to provide an agricultural multilayer film that substantially completely cuts out ultraviolet rays in a wide wavelength range that can be expected to have an ultraviolet shielding effect, and does not have a long-term decrease in ultraviolet-absorbing ability.
[0009]
[Means for Solving the Problems]
As a result of intensive studies, the inventor selected Si, Al, Mg, Ca, Li as a constituent component for any layer of a multilayer film having at least three layers having a total layer thickness of 0.3 mm or less. And an inorganic compound containing at least one atom in the entire layer of 3% or more, and at least one triazine-based UV absorber and at least one benzotriazole-based UV absorber. A multilayer film for agriculture characterized by being contained in a layer of, more preferably, an ultraviolet absorber content per unit volume in a layer other than the surface layer> an ultraviolet absorber content per unit volume in the surface layer The present invention has been completed by finding that the above-mentioned problems can be solved in an agricultural multilayer film characterized by the above.
[0010]
In the present invention, a specific ultraviolet absorber is added to the agricultural multilayer film using a specific method, and in particular, the benzotriazole ultraviolet absorber having a maximum absorption wavelength of 350 nm or more and the triazine ultraviolet absorber represented by the above formula (1) It has been found that by blending an agent, the ultraviolet wavelength region to the extent that an ultraviolet shielding effect can be expected is cut, and bleeding out to the resin surface is remarkably suppressed, so that a good ultraviolet absorption retention can be obtained. It was.
Conventionally, among ultraviolet absorbers, benzotriazoles have been used because they are suitable from the standpoint of absorption wavelength and the like, but these compounds have a drawback that they easily bleed out. Triazine-based UV absorbers have the property of being difficult to bleed out, but the absorption wavelength region is shifted to the shorter wavelength side than benzotriazole-based UV absorbers, and even when added in large amounts to agricultural films, some UV rays are transmitted. As a result, the ultraviolet shielding effect could not be sufficiently expected. Benzophenone-based ultraviolet absorbers are easy to bleed out and the wavelength region is shifted to the short wavelength side, and cannot be used for agricultural films that are expected to have an ultraviolet shielding effect.
[0011]
When an ultraviolet absorber is added to all layers of an agricultural multilayer film as in the normal agricultural film, the problem is that the ability to absorb ultraviolet rays decreases due to bleeding out from the film surface layer. It was. Under such background, the present invention exhibits a characteristic that the ultraviolet absorbing ability is hardly lowered when a specific ultraviolet absorber is used as an agricultural multilayer film unexpectedly, by a specific addition method, and for a long time. As a result of finding out that it can provide important performance as an agricultural film that is excellent not only in weather resistance, but also in controlling bacterial growth of fungi and fungi, pest control and deterioration prevention of lining materials, etc.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The agricultural multilayer film in the present invention is a film having a laminated structure of three or more layers having at least an outer layer, an intermediate layer, and an inner layer. Here, the outer layer means a layer that becomes the outer side when it is extended to a house, the inner layer means a layer that becomes the inner side when the house is extended, and the intermediate layer means a layer sandwiched between the outer layer and the inner layer. Say. Hereinafter, the outer layer and the inner layer may be collectively referred to as a surface layer. Further, as long as the effects of the present invention are not impaired, a resin layer may be further laminated between the inner layer and the intermediate layer, or between the outer layer and the intermediate layer, or the outer layer, the intermediate layer, the inner layer, and the like may be composed of two layers. The aspect made into a multilayer film of four or more layers is also included in the scope of the present invention. In this case, the intermediate layer is a layer other than the outer layer and the inner layer (other than the surface layer).
The layer thickness ratio of the outer layer / intermediate layer / inner layer in the present invention is not particularly limited. For example, the layer is 1/1/1 to 1/5/1, preferably 1/2/1 to 1/3/1. Formed in ratio.
In addition, the outer layer, the intermediate | middle layer, and inner layer said by this invention mean the layer comprised from the resin composition which added the other component to the resin main component which functions as an agricultural film. Therefore, as will be described later, a coating-type antifogging coating that is thinly applied on the inside of the inner layer for the purpose of antifogging properties, and other coatings that are formed on the outside of the outer layer for other purposes, The concept of the outer layer will be excluded.
For the agricultural multilayer film of the present invention, resins conventionally used as agricultural film resins, such as polyolefin resins, vinyl chloride resins, polyethylene terephthalate resins, can be used. The effect of the present invention is effectively exhibited.
Examples of polyolefin resins include α-olefin homopolymers, copolymers of different monomers mainly containing α-olefins, polyunsaturated compounds such as α-olefins and conjugated dienes or nonconjugated dienes, Examples include copolymers with acrylic acid, methacrylic acid, vinyl acetate, and the like, such as high density, low density or linear low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene. Examples include -4-methyl-1-pentene copolymer, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid copolymer. Among these, low density polyethylene having a density of 0.890 to 0.935, ethylene-α-olefin copolymer, and ethylene-vinyl acetate copolymer having a vinyl acetate content of 30% by weight or less are transparent and weather resistant. It is preferable as an agricultural film from the viewpoint of properties and price.
In the present invention, an ethylene-α-olefin copolymer resin obtained by copolymerization with a metallocene catalyst can be used as at least one component of the polyolefin resin.
[0013]
This is usually referred to as metallocene polyethylene, and is a copolymer of ethylene and an α-olefin such as butene-1, hexene-1, 4-methylpentene-1, octene.
[0014]
The ethylene-α-olefin copolymer used as at least one component of the polyolefin resin of the present invention preferably exhibits the following physical properties.
Melt flow rate (MFR)
The MFR measured according to JIS-K7210 is 0.01 to 10 g / 10 min, preferably 0.1 to 5 g / 10 min. If the MFR is larger than this range, the film meanders during molding and is not stable. On the other hand, if the MFR is too smaller than this range, the resin pressure at the time of molding increases and a load is applied to the molding machine. Therefore, the increase in pressure must be suppressed by reducing the production amount, which is not practical.
[0015]
density
The density measured by JIS-K7112 is 0.880 to 0.930 g / cm3, preferably 0.880 to 0.920 g / cm3. When the density is larger than this range, the transparency is deteriorated. On the other hand, if the density is smaller than this range, blocking occurs due to stickiness of the film surface, resulting in poor practicality.
[0016]
Molecular weight distribution
The molecular weight distribution (weight average molecular weight / number average molecular weight) determined by gel permeation chromatography (GPC) is 1.5 to 3.5, preferably 1.5 to 3.0. When the molecular weight distribution is larger than this range, the mechanical strength is lowered, which is not preferable. If the molecular weight distribution is smaller than this range, the film meanders during molding and is not stable.
[0017]
The ethylene-vinyl acetate copolymer resin used in the present invention has a vinyl acetate content of 3 to 25% by weight, preferably 5 to 20% by weight. If the vinyl acetate content is less than this range, the resulting film will be hard and will tend to wrinkle and sag when stretched in a house, which will have a negative effect on anti-fogging properties. If it is larger than the range, the melting point of the resin is low, so that the film loosens at high temperatures in summer during house extension, and is easily broken by wind and flapping with the house structure.
[0018]
The agricultural multilayer film in the present invention is characterized by containing a benzotriazole-based ultraviolet absorber. Usable benzotriazole-based ultraviolet absorbers are, for example, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-ditert-butylphenyl) Benzotriazole, 2- (2′-hydroxy-3 ′, 5′-ditert-butylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) ) -5-chlorobenzotriazole, 2- (2'-hydroxy-5'-tertiary octylphenyl) benzotriazole, 2- (2'-hydroxy-3'.5'-dicumylphenyl) benzotriazole, 2, 2- (2′-hydroxyphenyl) benzotriazoles such as 2′-methylenebis (4-tert-octyl-6-benzotriazolyl) phenol It is below.
Preferably, at least one benzotriazole-based ultraviolet absorber having a maximum absorption wavelength of 350 nm or more is required, and preferably two types are used.
Examples thereof include “TINUVIN 326” (maximum absorption wavelength 353 nm) “TINUVIN 327” (maximum absorption wavelength 352 nm) manufactured by Ciba Specialty Chemicals.
[0019]
The multilayer film for agriculture in the present invention is characterized by containing a triazine-based ultraviolet absorber. The triazine ultraviolet absorber used in the present invention is a triaryltriazine ultraviolet absorber represented by the following formula (1).
[0020]
[Chemical formula 2]

(1)
[0021]
Here, in Formula (1), R1-R5 represents a hydrogen atom or a C1-C10 alkyl group each independently. More preferably, R 1 is an alkyl group having 6 to 10 carbon atoms, particularly preferably an alkyl group having 6 to 8 carbon atoms, and R 2 to R 5 are hydrogen atoms or alkyl groups having 1 to 2 carbon atoms, particularly preferably. , A hydrogen atom or a methyl group.
[0022]
The method for obtaining the triaryltriazine-based ultraviolet absorber represented by the above formula (1) is not particularly limited, and commercially available products can be used. Examples thereof include TINUVIN 1577F manufactured by Ciba Specialty Chemicals and UV1164 manufactured by Cytec.
[0023]
The agricultural multilayer film in the present invention can be used in combination with other ultraviolet absorbers as long as the desired effect is not affected. Examples of UV absorbers that can be used in combination include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 5,5′-methylenebis (2-hydroxy-4- 2-hydroxybenzophenones such as methoxybenzophenone); phenyl salicylate, resorcinol monobenzoate, 2,4-ditert-butylphenyl-3 ′, 5′-ditert-butyl-4′-hydroxybenzoate, 2,4-di Benzoates such as tert-amylphenyl-3 ′, 5′-ditert-butyl-4′-hydroxybenzoate, hexadecyl-3,5-ditert-butyl-4-hydroxybenzoate; 2-ethyl-2′-ethoxy Substitution of oxanilide, 2-ethoxy-4'-dodecyloxanilide, etc. Kizanirido acids; ethyl -α- cyano-beta, beta-diphenylacrylate, cyanoacrylates such as methyl-2-cyano-3-methyl-3- (p-methoxyphenyl) acrylate. Moreover, inorganic oxide type ultraviolet absorbers such as zinc oxide and cerium oxide are also included. These ultraviolet absorbers are used alone or in combination of two or more.
[0024]
The content of the benzotriazole-based UV absorber and the triazine-based UV absorber in the agricultural multilayer film of the present invention is less than 2% by weight, preferably 0.1 to 1.5% by weight, based on the total film, respectively. More preferably, it is 0.2 to 1% by weight. When the content is less than the above range, the ultraviolet ray shielding effect is low. When the content exceeds the above range, there is a problem in whitening due to bleed-out when applied to an agricultural film that is a general agricultural film.
These ultraviolet absorbers are preferably added in an agricultural film containing both in an amount that substantially completely shields ultraviolet rays in the region of 200 nm to 370 nm.
[0025]
In a preferred embodiment of the present invention, X is the content (% by weight) of the UV absorber (total of two or more) based on the resin composition per unit volume of the intermediate layer, and the UV absorber content is per unit volume in the inner layer. When X is (Y) and X> Z, where Y is the weight percent and Y is the ultraviolet absorber content (% by weight) per unit volume in the outer layer, the effect of being able to retain the ultraviolet absorbing ability over a long period of time. Was found to be prominent.
In particular, when two specific types of ultraviolet absorbers of the present invention are used to form this layer, the same layer configuration is used for each single ultraviolet absorber, or the same combination of two types of other ultraviolet absorbers. Even when compared with the case of the layer configuration, it has a remarkable effect.
Here, Y and Z may be Y = Z or may be different. A particularly preferred embodiment is the case where Y = Z = 0.
Specifically, X, which is the content of the ultraviolet absorber with respect to the resin composition in the intermediate layer, is 0.1 to 3.0% by weight, preferably 0.15 to 2.0% by weight, and more preferably 0. The range of 2 to 1.0% by weight is mentioned. Y and Z include 0 to 2.0% by weight, preferably 0 or 0.001 to 0.5% by weight.
Furthermore, as a preferred embodiment of the present invention, there is an agricultural multilayer film having a laminated structure of at least three layers having at least an outer layer, an intermediate layer, and an inner layer, and no UV absorber is blended in the outer layer and the inner layer (surface layer). And an agricultural multilayer film characterized in that an ultraviolet absorber is blended in the intermediate layer.
[0026]
The agricultural multilayer film of the present invention has at least one atom selected from Si, Al, Mg, Ca, Li as a constituent component in at least one multilayer film having at least three layers having a total thickness of 0.3 mm or less. An inorganic compound containing is contained 3% in the entire film layer. As an inorganic compound that can be used, for example, an infrared absorber (heat retention agent) and a filler can be exemplified.
[0027]
The infrared absorbent (heat retention agent) is inorganic fine particles having infrared absorbing ability, and these can be used alone or in combination of two or more. The inorganic fine particles that can be used are not particularly limited, but are inorganic compounds containing at least one atom selected from the components: Si, Al, Mg, Ca, Li. For example, magnesium oxide, calcium oxide, aluminum oxide, silicon oxide, lithium hydroxide, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, magnesium carbonate, calcium carbonate, calcium sulfate, magnesium sulfate, aluminum sulfate, lithium phosphate, calcium phosphate , Magnesium silicate, calcium silicate, aluminum silicate, calcium aluminate, magnesium aluminate, sodium aluminosilicate, potassium aluminosilicate, calcium aluminosilicate, kaolin, clay, talc, mica, zeolite, hydrotalcite compound, lithium aluminum composite Hydroxides, aluminum / lithium / magnesium composite carbonate compounds, aluminum / lithium / magnesium composite silicate compounds, magnesium / aluminum Um silicon composite hydroxide, magnesium aluminum silicon composite sulfate compounds, magnesium aluminum silicon composite carbonate compound, a metal complex hydroxide salt containing more anions. These may be obtained by dehydrating crystal water.
[0028]
The inorganic fine particles used as the infrared absorber (heat retention agent) may be natural products or synthetic products. The inorganic fine particles can be used without being limited by the crystal structure, crystal particle diameter, and the like.
[0029]
The inorganic fine particles used as the infrared absorbing agent (heat retention agent) have a surface having a higher fatty acid such as stearic acid, a higher fatty acid metal salt such as an alkali metal oleate, or an organic sulfonic acid such as an alkali metal dodecylbenzenesulfonate. Those coated with metal salts, higher fatty acid amides, higher fatty acid esters or waxes can also be used.
[0030]
The inorganic fine particles used as the infrared absorber (heat retention agent) can be used alone or in combination of two or more. The average particle diameter is preferably in the range of 0.05 to 15 μm, more preferably 0.1 to 10 μm. If the average particle size of the inorganic fine particles is smaller than the above range, the dispersibility in the resin is inferior, and the appearance of the film is deteriorated and the appearance of the film is deteriorated. The handling is severely inferior. On the other hand, if the average particle size of the inorganic fine particles is larger than the above range, the transparency is inferior or clogging occurs in the extruder breaker screen, and the productivity deteriorates.
[0031]
The filler may be, for example, silica, talc, aluminum hydroxide, hydrotalcite, calcium sulfate, calcium silicate, calcium hydroxide, water, in order to suppress stickiness of the film or to further improve heat retention. Magnesium oxide, kaolin clay, mica, alumina, magnesium carbonate, sodium aluminate, conductive zinc oxide, lithium phosphate and the like are used. One type of these fillers may be used, or two or more types may be used in combination.
[0032]
The amount of these inorganic compounds used is 3 to 30% by weight, more preferably 3 to 20% by weight, and still more preferably 3 to 15% by weight in the entire film layer. If it is less than 3% by weight, the effects of the present invention cannot be fully exhibited. If it exceeds 30% by weight, transparency and mechanical strength as an agricultural film are inferior and economically disadvantageous.
[0033]
In the multilayer film for agriculture used in the present invention, a hindered amine compound can be added as a weathering agent to at least one layer in the multilayer film. Moreover, this hindered amine compound can be used 1 type or in combination of 2 or more types. Of course, the hindered amine compound may contain the same type in all layers, but for example, the innermost layer and the outermost layer (house outer surface) contain a high molecular weight type that does not bleed out, and the other layers are usually blended for agricultural use. A hindered amine compound can also be contained. These high molecular weight hindered amine compounds may be copolymerized with ethylene or other monomers (for example, ethylene / cyclic aminovinyl compound copolymer), or may be grafted onto polymers such as polyethylene. In that case, for example, the same layer may contain an ethylene / cyclic aminovinyl compound copolymer and a hindered amine light stabilizer usually blended for agriculture.
[0034]
The hindered amine light weathering agent normally blended for use in agriculture can be a hindered amine compound having at least two piperidine ring structures in the molecule and a molecular weight of 500 or more (hereinafter also referred to as “piperidine ring-containing hindered amine compound”). ) Is preferred. Here, if the number of piperidine rings of the piperidine ring-containing hindered amine compound is less than 2, sufficient weather resistance cannot be obtained, and if the molecular weight is less than 500, volatilization tends to occur and long-term weather resistance cannot be obtained. The number of piperidine rings in the piperidine ring-containing hindered amine compound is preferably 2 to 50, and the molecular weight is preferably 750 or more.
[0035]
Examples of the piperidine ring-containing hindered amine compound include bis (1,2,2,6,6-pentamethyl-4-piperidyl) -2-butyl-2- (3,5-ditert-butyl-4-hydroxybenzyl). ) Malonate, tetra (2,2,6,6-tetramethyl-4-piperidyl) butanetetracarboxylate, tetra (1,2,2,6,6-pentamethyl-4-piperidyl) butanetetracarboxylate, bis ( 2,2,6,6-tetramethyl-4-piperidyl) .di (tridecyl) butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) .di (tridecyl) butanetetra Carboxylate, 3,9-bis [1,1-dimethyl-2- {tris (2,2,6,6-tetramethyl-4-piperidyloxy Rubonyloxy) butylcarbonyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane, 3,9-bis [1,1-dimethyl-2- {tris (1,2,2) , 6,6-pentamethyl-4-piperidyloxycarbonyloxy) butylcarbonyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane, 1,5,8,12-tetrakis [4 , 6-Bis {N- (2,2,6,6-tetramethyl-4-piperidyl) butylamino} -1,3,5-triazin-2-yl] -1,5,8,12-tetraaza Dodecane, 1- (2-hydroxyethyl) -2,2,6,6-tetramethyl-4-piperidinol / dimethyl succinate condensate, 2-tert-octylamino-4,6-dichloro-s-triazine N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylenediamine condensate, N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) And hexamethylenediamine / dibromoethane condensate. Examples of commercially available hindered amine compounds that can be used include TINUVIN 770, TINUVIN 780, TINUVIN 144, TINUVIN 622LD, TINUVIN NOR 371, CHIMASSORB 119FL, CHIMASSORB 944 (above, manufactured by Ciba Geigy), Sanol LS-765 (Sankyo R / K) -63, MARK LA-68, MARK LA-68, MARK LA-62, MARK LA-67, MARK LA-57, LA-900 (manufactured by Asahi Denka Co., Ltd.), UV-3346, UV-3529, UV-3581, UV-3853 (above, manufactured by Cytec), Hostabin N20, Hostabin N24, Hostabin N30, Hostabin 845, Sanduboa PR-31, Nyrostub S -EED (above, Clariant Japan Co., Ltd.) etc. are mentioned. These piperidine ring-containing hindered amine compounds are used alone or in combination of two or more.
[0036]
In the thermoplastic resin film of the present invention, various additives usually used for synthetic resins can be used in combination. Examples of these additives include metal organic acid salts, basic organic acid salts and overbased organic acid salts, hydrotalcite compounds, epoxy compounds, β-diketone compounds, polyhydric alcohols, halogen oxyacid salts, Examples thereof include sulfur-based, phenol-based and phosphite-based antioxidants, heat stabilizers, lubricants, antistatic agents, coloring agents, antiblocking agents, antifogging agents, and antifogging agents.
[0037]
Examples of the metal species constituting the organic acid salt, basic organic acid salt and overbased organic acid salt of the metal include Li, Na, K, Ca, Ba, Mg, Sr, Zn, Cd, Sn, Cs, Examples of the organic acid include carboxylic acid, organic phosphoric acid, and phenol. Examples of the carboxylic acid include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, Caprylic acid, neodecanoic acid, 2-ethylhexylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, isostearic acid, stearic acid, 12-hydroxystearic acid, behenic acid, montanic acid, Elaidic acid, oleic acid, linoleic acid, linolenic acid, thioglycolic acid, mercaptopropionic acid, octyl mercapto Lopionic acid, benzoic acid, monochlorobenzoic acid, p-tert-butylbenzoic acid, dimethylhydroxybenzoic acid, 3,5-ditert-butyl-4-hydroxybenzoic acid, toluic acid, dimethylbenzoic acid, ethylbenzoic acid, cumin Acids, n-propylbenzoic acid, acetoxybenzoic acid, salicylic acid, p-tertiary octylsalicylic acid and other monovalent carboxylic acids, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid , Divalent carboxylic acids such as sebacic acid, maleic acid, fumaric acid, citraconic acid, metaconic acid, itaconic acid, aconitic acid, thiodipropionic acid, phthalic acid, isophthalic acid, terephthalic acid, oxyphthalic acid, chlorophthalic acid, etc. Monoester or monoamide compound, butanetricarboxylic acid, butane Examples thereof include di- or triester compounds of trivalent or tetravalent carboxylic acids such as tracarboxylic acid, hemimellitic acid, trimellitic acid, merophanic acid, and pyromellitic acid, and examples of the organic phosphoric acid include mono- or dioctylphosphoric acid. Acid, mono or didodecyl phosphoric acid, mono or dioctadecyl phosphoric acid, mono or di- (nonylphenyl) phosphoric acid, phosphonic acid nonylphenyl ester, phosphonic acid stearyl ester, etc., and the phenols include phenol, cresol , Xylenol, methylpropylphenol, methyl tertiary octylphenol, ethylphenol, isopropylphenol, tertiary butylphenol, n-butylphenol, diisobutylphenol, isoamylphenol, diamylphenol, isohexylphenol Enol, octylphenol, isooctylphenol, 2-ethylhexylphenol, tertiary octylphenol, nonylphenol, dinonylphenol, tertiary nonylphenol, decylphenol, dodecylphenol, octadecylphenol, cyclohexylphenol, phenylphenolphenol, cresol, ethylphenol, cyclohexylphenol, nonylphenol And dodecylphenol.
[0038]
Although there is no restriction | limiting in particular about the said anti-fogging agent, It consists of polyhydric alcohol and higher fatty acids including well-known various nonionic surfactant, anionic surfactant, cationic surfactant, etc. A polyhydric alcohol partial ester type is preferred. Specific examples of such an antifogging agent include, for example, nonionic surfactants such as sorbitan monostearate, sorbitan monomyristate, sorbitan monopalmitate, sorbitan monobehenate, sorbitan / alkylene glycol condensate and fatty acid. Sorbitan surfactants such as esters with glycerol monopalmitate, glycerol monostearate, glycerol monolaurate, diglycerol monopalmitate, glycerol dipalmitate, glycerol distearate, diglycerol monopalmitate monostearate Glycerin-based surfactants such as glycerol, monoglycerate, triglycerin monostearate, triglycerin distearate or alkylene oxide adducts thereof, polyethylene glycol monostearate, polyethylene glycol Polyethylene glycol surfactants such as coal monopalmitate, polyethylene glycol alkyl phenyl ether, and other trimethylolpropane surfactants such as trimethylolpropane monostearate, and pentaerythritol monopalmitate, pentaerythritol monostearate, etc. Erythritol surfactant, alkylene oxide adduct of alkylphenol; sorbitan / glycerin condensate and fatty acid ester, sorbitan / alkylene glycol condensate and fatty acid ester; diglycerin dioleate sodium lauryl sulfate, dodecylbenzenesulfonic acid Sodium, cetyltrimethylammonium chloride, dodecylamine hydrochloride, lauric acid laurylamide ethyl phosphate It can be exemplified triethylammonium cetyl ammonium iodide, oleyl amino diethylamine hydrochloride, and those containing dodecyl pyridinium salts, etc. and their isomers.
[0039]
Examples of the anti-fogging agent include a fluorine-based surfactant and a silicone-based surfactant. Specific examples of the fluorine-based surfactant include, instead of H bonded to C of the hydrophobic group of a normal surfactant. In addition, a surfactant having a part or all thereof substituted with F, particularly a surfactant containing a perfluoroalkyl group or a perfluoroalkenyl group. The above various additives can be used alone or in combination of two or more. Examples of the fluorine-containing compound having a perfluoroalkyl group include an anionic fluorine-containing surfactant, a cationic fluorine-containing surfactant, an amphoteric fluorine-containing surfactant, a nonionic fluorine-containing surfactant, and a fluorine-containing oligomer. can give.
[0040]
The amount of the fluorine-containing compound having a perfluoroalkyl group is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the thermoplastic resin. If the amount of the fluorine-containing compound used is less than 0.001 part by weight, the antifogging effect is hardly exhibited, and if it exceeds 10 parts by weight, the effect is saturated, which is not preferable.
[0041]
Examples of the phenol-based antioxidant include 2,6-ditert-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, stearyl (3,5-ditert-butyl-4- Hydroxyphenyl) -propionate, distearyl (3,5-ditert-butyl-4-hydroxybenzyl) phosphonate, thiodiethylene glycol bis [(3,5-ditert-butyl-4-hydroxyphenyl) propionate], 1,6 -Hexamethylene bis [(3,5-ditert-butyl-4-hydroxyphenyl) propionate], 1,6-hexamethylene bis [(3,5-ditert-butyl-4-hydroxyphenyl) propionic acid amide] 4,4′-thiobis (6-tert-butyl-m-cresol), 2,2′-methylenebis (4-methyl-6- Tributylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), bis [3,3-bis (4-hydroxy-3-tert-butylphenyl) butyric acid] glycol ester, 4, 4'-butylidenebis (6-tert-butyl-m-cresol), 2,2'-ethylidenebis (4,6-ditert-butylphenol), 2,2'-ethylidenebis (4-secondarybutyl-6- Tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, bis [2-tert-butyl-4-methyl-6- (2-hydroxy-3) -Tert-butyl-5-methylbenzyl) phenyl] terephthalate, 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate 1,3,5-tris (3,5-ditert-butyl-4-hydroxylbenzyl) isocyanurate, 1,3,5-tris (3,5-ditert-butyl-4-hydroxybenzyl) 2,4,6-trimethylbenzene, 1,3,5-tris [(3,5-ditert-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate, tetrakis [methylene-3- (3,5 -Di-tert-butyl-4-hydroxyphenyl) propionate] methane, 2-tert-butyl-4-methyl-6- (2-acryloyloxy-3-tert-butyl-5-methylbenzyl) phenol, 3,9- Bis [1,1-dimethyl-2-{(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5. ] Undecane, triethylene glycol bis [(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], n-octadecyl 3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) ) Propionate, tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxymethyl] methane and the like.
[0042]
Examples of the sulfur-based antioxidant include dialkylthiodipropionates such as dilauryl thiodipropionate, dimyristyl, and distearyl, and β-alkyl mercapto of polyols such as pentaerythritol tetra (β-dodecyl mercaptopropionate). And propionic acid esters.
[0043]
Examples of the phosphite-based antioxidant include trisnonylphenyl phosphite, tris (2,4-ditert-butylphenyl) phosphite, tris [2-tert-butyl-4- (3-tert-butyl- 4-hydroxy-5-methylphenylthio) -5-methylphenyl] phosphite, tridecyl phosphite, octyl diphenyl phosphite, di (decyl) monophenyl phosphite, monodecyl diphenyl phosphite, mono (dinonylphenyl) Bis (nonylphenyl) phosphite, di (tridecyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite, bis (2,4-ditertiarybutylphenyl) penta Erythritol diphosphie Bis (2,6-ditert-butyl-4-methylphenyl) pentaerythritol diphosphite, tetra (tridecyl) isopropylidenediphenol diphosphite, tetra (tridecyl) isopropylidenediphenol diphosphite, tetra (C 12-15 mixed alkyl) -4,4′-n-butylidenebis (2-tert-butyl-5-methylphenol) diphosphite, hexa (tridecyl) -1,1,3-tris (2-methyl-4-hydroxy-) 5-tert-butylphenyl) butanetriphosphite, tetrakis (2,4-ditert-butylphenyl) biphenylene diphosphonite, 2,2′-methylenebis (4,6-ditert-butylphenyl) (octyl) phosphite , Tetrakis (2,4-di-t-butylphenyl) 4,4′-biphenylene-di Phosphonites, 2,2-methylenebis (4,6-di -t- butyl phenyl) octyl phosphite, and the like.
[0044]
Examples of the colorant include phthalocyanine blue, phthalocyanine green, hansa yellow, alizarin lake, titanium oxide, zinc white, ultramarine blue, permanent red, quinacridone, and carbon black.
[0045]
Examples of the anti-blocking agent include diatomaceous earth, synthetic silica, talc, mica and zeolite. These anti-blocking agents can be used alone or in combination of two or more, and the range of usually 0.01 to 0.5% by weight is preferred.
[0046]
The thermoplastic resin film of the present invention contains the above-described components in combination, and can further contain the following optional components that can be contained in the thermoplastic resin film of the present invention as necessary. . Optional components include other stabilizers, impact resistance improvers, cross-linking agents, fillers, foaming agents, antistatic agents, nucleating agents, plate-out preventing agents, surface treatment agents, flame retardants, fluorescent agents, anti-glare agents Agents, bactericides, metal deactivators, mold release agents, pigments, processing aids and the like.
[0047]
The thermoplastic resin film of the present invention is each weighed in a necessary amount for blending various additives, and blending machines such as a ribbon blender, a Banbury mixer, a Henschel mixer, a super mixer, a single or twin screw extruder, a roll, A kneader or other conventionally known blender or mixer may be used. In order to form the resin composition thus obtained into a film, a method known per se, for example, a melt extrusion molding method (including a T-die method and an inflation method), calendar processing, roll processing, extrusion molding processing, Blow molding, inflation molding, melt casting, pressure molding, paste processing, powder molding, and the like can be suitably used.
[0048]
About the thermoplastic resin film thickness of this invention, the thing of the range of 0.03-0.3 mm is preferable at the point of intensity | strength or cost, and the thing of 0.05-0.2 mm is more preferable. If it is less than this range, there is a problem in strength, and if it exceeds this range, molding becomes difficult.
[0049]
In the present invention, when a polyolefin resin is used for the base material layer, an antifogging film can be formed in contact with the innermost layer of the polyolefin base material.
As the anti-fogging coating film in the present invention, an anti-fogging coating film which can be used for an already known agricultural film can be applied. Preferably, an antifogging coating film mainly composed of an inorganic colloid material and a hydrophilic organic compound or an antifogging coating film mainly composed of an inorganic colloid material and an acrylic resin can be used.
[0050]
Examples of anti-fogging coatings mainly composed of an inorganic colloid material and a hydrophilic organic compound that can be used in the present invention include, for example, Japanese Patent Publication No. 63-45432, Japanese Patent Publication No. 63-45717, Japanese Patent Publication No. 64-2158, and patents. And compounds shown in No. 3094296.
[0051]
In the present invention, an antifogging film mainly composed of an acrylic resin and an inorganic colloidal sol can also be suitably used.
As one example preferably used as the acrylic resin, at least a total of 60% by weight of a monomer composed of alkyl esters of acrylic acid or methacrylic acid, or an alkyl ester of acrylic acid or methacrylic acid and an alkenylbenzene The monomer mixture and 0 to 40% by weight of copolymerizable α, β-ethylenically unsaturated monomer are subjected to emulsion polymerization in an aqueous medium in the presence of an emulsifier, for example, according to normal polymerization conditions. The hydrophobic acrylic resin which is the obtained water dispersible polymer or copolymer can be mentioned.
The acrylic resin used in the present invention is preferably a hydrophobic acrylic resin, that is, an alkyl ester of acrylic acid or methacrylic acid as described above, or an alkyl ester of acrylic acid or methacrylic acid and an alkenylbenzene. It is preferable to contain a monomer mixture with at least 60% by weight, preferably 80% by weight or more. When it is less than 60% by weight, the water resistance of the formed film is not sufficient, and therefore, the anti-fogging sustainability may not be exhibited, which is not preferable.
In particular, the acrylic resin of the present invention preferably has a glass transition temperature of 35 to 80 ° C. If the glass transition temperature is too low, the inorganic colloidal particles are agglomerated several times and tend to be in a non-uniform dispersion state. If it is too high, it is difficult to obtain a transparent uniform film.
[0052]
In the present invention, the thickness of the coating film formed on the surface of the substrate film may be selected by using 1/10 or less of the substrate film as a guide, but is not necessarily limited to this range. If the thickness of the coating is larger than 1/10 of the base film, there is a difference in flexibility between the base film and the coating, so that a phenomenon such as peeling of the coating from the base film is likely to occur, and the coating is cracked. This is not preferable because a phenomenon occurs in which the strength of the base film is lowered.
[0053]
When the adhesion between the base film and the coating derived from the coating composition is not sufficient, the base film may be subjected to a surface treatment. Examples of the treatment method applied to the surface of the laminated film of the present invention include corona discharge treatment, sputter etching treatment, sodium treatment, and sandblast treatment. In the corona discharge treatment method, discharge is performed between a needle-like or knife-edge electrode and a counter electrode, and a sample is placed between the electrodes, and the film surface contains oxygen such as aldehyde, acid, alcohol peroxide, ketone, ether, etc. This is a process for generating a functional group. In the sputter etching process, a sample is placed between electrodes that are performing low-pressure glow discharge, and a large number of fine protrusions are formed on the film by the impact of positive ions generated by the glow discharge. In the sandblasting process, fine sand is sprayed on the film surface to form a large number of fine irregularities on the surface. Among these surface treatments, corona discharge treatment is preferable from the viewpoints of adhesion to the coating layer, workability, safety, cost, and the like.
[0054]
When the thermoplastic resin film for agriculture according to the present invention is actually used, it is preferably stretched so that the side provided with the anti-fogging coating is inside the house or tunnel.
The agricultural multilayer film of the present invention thus obtained can substantially completely shield ultraviolet rays of 200 nm to 370 nm. “Substantially completely shielded” means that the light transmittance is 0 to 2% or less in the state of an unused agricultural film.
[0055]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example and a comparative example, this invention is not limited to the following examples, unless the summary is exceeded.
[0056]
(1) Adjustment of laminated film (both antifogging agent kneading type and antifogging coating application type) As a three-layer inflation molding device, a three-layer die with 100 mmφ (manufactured by Pla Koken Co., Ltd.) is used. The inner layer is 30 mmφ (manufactured by Pla Giken Co., Ltd.) and the intermediate layer is 40 mmφ (manufactured by Pla Giken Co., Ltd.), the outer inner layer extruder temperature is 180 ° C., the intermediate layer extruder temperature is 170 ° C., and the die temperature is 180 to 190 ° C. A three-layer laminated film comprising the components shown in Table-2 to Table-7 was obtained at a blow ratio of 2.0 to 3.0, a take-up speed of 3 to 7 m / min, and a thickness of 0.15 mm. Since these films are used with the end of the tube cut open when the house is stretched, the tube outer layer during film formation becomes the inner layer (inner surface) of the house when stretched when unfolded.
[0057]
[Composition] Addition amounts are as described in each table.
HP-LDPE: Branched polyethylene produced with a high-pressure radical catalyst (MFR: 1.1 g / 10 min, density 0.920) Novatec LD “YF30” manufactured by Nippon Polychem
Metallocene PE: An ethylene / α-olefin copolymer produced with a metallocene catalyst (MFR: 2 g / 10 min, density 0.907) Kernel “KF270” manufactured by Nippon Polychem
EVA (1): ethylene / vinyl acetate copolymer (vinyl acetate content 5% by weight, MFR 2 g / 10 min)
EVA (2): ethylene / vinyl acetate copolymer (vinyl acetate content 15% by weight, MFR 2 g / 10 min)
Kimasorb 944: Light stabilizer made by Ciba Specialty Chemicals
Ethylene / Cyclic aminovinyl copolymer: “NOVATEC LD / XJ100H” manufactured by Nippon Polychem Co., Ltd. MFR = 3 g / 10 min (190 ° C., JIS-K6760) Density = 0.931 g / cm3 (JIS-K6760) Cyclic aminovinyl Compound content = 5.1% by weight (0.7 mol%) Percentage of cyclic aminovinyl compound present in isolation = 90 mol% Melting point = 111 ° C.
Triaryltriazine compound UV absorber A: Triaryltriazine compound in which R1 is an octyl group and R2 to R5 are methyl groups
Triaryltriazine-based ultraviolet absorber B: Triaryltriazine compound in which R1 is a hexyl group and R2 to R5 are hydrogen atoms
Benzotriazole UV absorber A: TINUVIN 326 manufactured by Ciba Specialty Chemicals
Benzotriazole UV absorber B: TINUVIN 327 manufactured by Ciba Specialty Chemicals
Benzophenone ultraviolet absorber A: Siasorb UV-531 manufactured by Cytec Corporation
Benzophenone UV absorber B: Siasorb UV-9 manufactured by Cytec
[0058]
(2) Surface treatment of film
The outer layer surface of the obtained tubular film was subjected to corona discharge treatment at a discharge voltage of 120 V, a discharge current of 4.7 A, and a line speed of 10 m / min, and the “wetting index” according to JIS-K6768 was measured, and the value was confirmed. .
[0059]
(3) Formation of anti-fogging coating film (anti-fogging coating type)
The main component (silica sol and / or alumina sol) shown in Table 1, a thermoplastic resin, a crosslinking agent, and a liquid dispersion medium were blended to obtain an antifogging agent composition.
The antifogging agent composition was blended as follows.
Inorganic colloidal sol (colloidal silica) 4.0
Thermoplastic resin (Sanmor SW-131) 3.0
Cross-linking agent (TAZM) 0.1
Dispersion medium (water / ethanol = 3/1) 93
(Note) The amount of inorganic colloidal sol is indicated by the amount of inorganic particles, and the amount of thermoplastic resin is indicated by the solid content of the polymer.
Colloidal silica: Snowtex 30 manufactured by Nissan Chemical Co., Ltd., average particle size 15 mμ
Sunmole SW-131: Sanyo Chemical Co., Ltd. acrylic emulsion
T.A. A. Z. M: Aziridine compound manufactured by Mutual Yakugyo Co., Ltd.
The antifogging agent composition was applied to the surface of the base film surface-treated in (2) using a # 5 bar coater. The applied film was kept in an oven at 80 ° C. for 1 minute to volatilize the liquid dispersion medium to form an antifogging coating film. The thickness of the coating film of each obtained film was about 1 μm.
[0060]
This time, a test was performed using a type provided with an antifogging coating film (film thickness 150 μm), but the same effect can be obtained with a type in which an antifogging agent is mixed. Moreover, the same effect is acquired even if it is a combination other than the resin used this time, an additive, or film thickness different from this time, unless the summary is changed. The following optical characteristics were measured for each sample used this time. Each measuring method in an Example and a comparative example is shown below.
[0061]
▲ 1 ▼ Transparency
A laminated film obtained by three-layer inflation molding on a pipe house constructed in the above-mentioned field of Abe Prefecture Kaifu-gun (in the case of a type in which an antifogging coating is applied, an antifogging coating is formed on the inner layer side surface of the house (coating After construction))) was spread out in a sealed state. From the end of August 1999 to the end of November 2002, a part of the film being spread in the pipe house was sampled, and the transparency (straight light transmittance at a wavelength of 555 nm) was measured with a spectrophotometer (manufactured by Hitachi, Ltd.). , U3500 type) and indicated the value.
[0062]
(2) UV absorption ability retention
A laminated film obtained by three-layer inflation molding on a pipe house constructed in the above-mentioned field of Abe Prefecture Kaifu-gun (in the case of a type in which an antifogging coating is applied, an antifogging coating is formed on the inner layer side surface of the house (coating After construction))) was spread out in a sealed state. From the end of August 1999 to the end of November 2002, a part of the film being spread in the above pipe house was sampled, and its ultraviolet absorptivity (total light transmittance at a wavelength of 325 nm) was measured with a spectrophotometer (Hitachi, Ltd.). Manufactured, U3500 type) and measured.
[0063]
[Examples 1 to 6] A three-layer film having a film thickness of 150 μm and a layer ratio of 1/3/1 by using the above-mentioned composition in which a triazine ultraviolet absorber and a benzotriazole ultraviolet absorber are combined with an inorganic filler as an ultraviolet absorber. (Anti-fog coating application type) was prepared, and the initial transparency, transparency change with time, initial ultraviolet absorption ability, ultraviolet absorption ability change with time, and the like were measured by the above-described methods, and each film was evaluated. The results are shown in [Table 1] and [Table 2].
[Table 1]

[Table 2]

[0064]
[Comparative Examples 1 to 5] A triazine-based ultraviolet absorber and a benzotriazole-based ultraviolet absorber as the ultraviolet absorber are combined with no inorganic filler, and the above-described combination using only the triazine-based ultraviolet absorber is 150 μm in film thickness. Create a three-layer film (antifogging coating type) with a layer ratio of 1/3/1, and measure the initial transparency, transparency change with time, initial UV absorption ability, UV absorption ability change with time, etc. Each film was evaluated. The results are shown in [Table 3].
[Table 3]

[0065]
[Comparative Examples 6 to 9] A three-layer film (antifogging coating film) having a film thickness of 150 μm and a layer ratio of 1/3/1 by the above-mentioned formulation using only a benzotriazole-based ultraviolet absorber as an ultraviolet absorber in combination with an inorganic filler. Application type) was prepared, and the initial transparency, transparency change with time, initial ultraviolet absorption ability, ultraviolet absorption ability change with time, etc. were measured by the above-mentioned methods, and each film was evaluated. The results are shown in [Table 4].
[Table 4]

[0066]
[Comparative Examples 10 to 14] A three-layer film having a film thickness of 150 μm and a layer ratio of 1/3/1 (anti-fogging coating coating type) by using the above-mentioned composition using a benzophenone ultraviolet absorber in combination with an inorganic filler as an ultraviolet absorber. ) Was measured, and the initial transparency, transparency change with time, initial ultraviolet absorption ability, ultraviolet absorption ability change with time, and the like were measured by the above-described methods, and each film was evaluated. The results are shown in [Table 5].
[Table 5]

[0067]
As is clear from the above results, it can be seen that when a triazine-based UV absorber and a benzotriazole-based UV absorber are added to the film in combination with an inorganic filler, a wide UV absorption range and good UV absorbing ability retention can be imparted. Further, an ultraviolet absorber is added to other than the surface layer of the multilayer film (other than the inner layer of the house and the outer layer of the house: the intermediate layer), or the ultraviolet absorber content per unit volume in the intermediate layer X> per unit volume in the inner layer It was found that the effect of maintaining the ultraviolet absorbing ability over a long period of time was remarkable when the addition was made so that the ultraviolet absorber content Y of X and X> the ultraviolet absorber content Z per unit volume in the outer layer. These agricultural multilayer films that have a broad UV absorption wavelength range and excellent long-term retention of UV-absorbing ability are used to control the growth of pests and fungi, pest control, and lining materials in the house environment over a long period of time. Excellent anti-degradation properties, etc., and absorbs ultraviolet rays that cause deterioration of agricultural multilayer film base materials over a long period of time, extending film life and suppressing bleed-out that causes deterioration of coating film adhesion Therefore, good coating film adhesion can be obtained over a long period of time.
[0068]
On the other hand, when the addition method other than the present invention is used (Comparative Examples 1 to 14), the ultraviolet absorbing ability is not retained or the ultraviolet absorbing region cannot be provided and used for a long time. In addition, it is difficult to suppress the propagation of pests and fungi, pest control, and deterioration prevention of lining materials in the house environment. That is, it is difficult to maintain the performance as an ultraviolet cut film, and there is a very problem in the properties of the product.
[0069]
That is, if the addition method of the present invention is not used, it is difficult to maintain the ultraviolet absorption ability over a long period of time while having a wide ultraviolet absorption wavelength region under harsh conditions such as agricultural use, and a specific addition method is further required. It can be applied to a film of a type to which an anti-fogging coating film is applied because it can maintain a very good ultraviolet absorbing ability while suppressing bleeding out. Therefore, when adapting to an agricultural film, the specific ultraviolet absorber and inorganic filler (and a specific addition method) of the present invention, which are constituent elements, are essential. Retention cannot be maintained.
【The invention's effect】
The agricultural multilayer film of the present invention is excellent in ultraviolet shielding (absorption wavelength range is wide) because the ultraviolet absorbent is difficult to bleed out on the resin surface, and its performance is maintained even when used for a long time. It is suitable for use as an agricultural film, because it is excellent in controlling the growth of pests and fungi in the internal environment, pest control, and deterioration prevention of lining materials, and does not impair the adhesion and weather resistance of the coating over a long period of time. Can do. In addition, when an anti-fogging coating film is provided on the film, it is preferable because bleeding out is suppressed and adhesion with the base material is not lowered. The film using the polyolefin resin composition of the present invention may be transparent, satin or semi-satin, and is used for agricultural films for house, tunnel, mulching, bag hanging, etc. , Agricultural PO, hard film, etc.).

Claims (6)

An inorganic compound containing at least one atom selected from Si, Al, Mg, Ca and Li as a constituent component in any layer of a multilayer film having at least three layers with a total thickness of 0.3 mm or less Agriculturally characterized by containing 3% or more in all layers and containing at least one or more triazine-based UV absorbers and at least one or more benzotriazole-based UV absorbers in at least an intermediate layer Multilayer film. Agricultural multi-layer film according to claim 1, wherein at least one of the maximum absorption wavelength in the base benzotriazole-based ultraviolet absorber is 350nm or more. Adding conditions of ultraviolet absorber, agricultural multi-layer film according to claim 1 or 2, characterized by satisfying the following condition.
UV absorber content rate X per unit volume in the intermediate layer> UV absorber content rate Y per unit volume in the inner layer, and X> UV absorber content rate Z per unit volume in the outer layer. The agricultural multilayer film according to any one of claims 1 to 3, wherein an ultraviolet absorber is added to a surface layer other than the surface layer of the multilayer film (other than the house inner layer and the house outer layer: an intermediate layer). . DOO triazine-based UV absorber, characterized in that it is a triaryl triazine ultraviolet absorber represented by the following formula (1), agricultural multi-layer film according to any one of claims 1 to 4.

(In formula, R1-R5 represents a hydrogen atom or a C1-C10 alkyl group each independently.) The agricultural multilayer film according to any one of claims 1 to 5 , wherein ultraviolet rays of 200 nm to 370 nm are substantially completely shielded.