JP4133158B2 - Modified polyvinyl acetal resin - Google Patents

Description

【００５５】
式（１）中、Ｘは、ポリビニルアルコール混合物の全体としてのエチレン含有率を表し、Ａ_１は、ポリビニルアルコールＡの重量を表し、Ａ_２は、ポリビニルアルコールＡのエチレン含有率を表し、Ｂ_１は、ポリビニルアルコールＢの重量を表し、Ｂ_２は、ポリビニルアルコールＢのエチレン含有率を表す。
【００５６】
また、本発明２の変性ポリビニルアセタール樹脂の全体としてのエチレン含有率（モル％）についても同様の方法により求めることができるが、これは、アセタール化する前のポリビニルアルコール混合物の値と同じであるので、変性ポリビニルアルコール混合物を構成するポリビニルアルコールのそれぞれについてエチレン含有率がわかっている場合はこれを用いることができる。また、ポリビニルアルコール混合物の全体としてのエチレン含有率が１〜２０モル％であることにより、アセタール化して得られる本発明２の変性ポリビニルアセタール樹脂の全体としてのエチレン含有率も１〜２０モル％となる。
【００５７】
上記ポリビニルアルコール混合物は、全体としてのケン化度が８０モル％以上である。８０モル％未満であると、ポリビニルアルコール混合物の水溶性が低下するためアセタール化反応が困難になり、水酸基量が少なくなることによりアセタール化反応自体も困難になる。
【００５８】
なお、本明細書において、上記ポリビニルアルコール混合物の全体としてのケン化度（モル％）は、上記ポリビニルアルコール混合物を構成する各ポリビニルアルコールのケン化度に重量比を掛け、その総和を求めたものである。例えば、変性ポリビニルアルコールＡと変性ポリビニルアルコールＢとからなるポリビニルアルコール混合物については、下記式（２）より全体としてのケン化度（モル％）が求められる。
【００５９】
【数２】

【００６０】
式（２）中、Ｙは、ポリビニルアルコール混合物の全体としてのケン化度を表し、Ａ_１は、ポリビニルアルコールＡの重量を表し、Ａ_３は、ポリビニルアルコールＡのケン化度を表し、Ｂ_１は、ポリビニルアルコールＢの重量を表し、Ｂ_３は、ポリビニルアルコールＢのケン化度を表す。
【００６１】
また、本発明２の変性ポリビニルアセタール樹脂の全体としてのケン化度（モル％）についても同様の方法により求めることができるが、これは、アセタール化する前のポリビニルアルコール混合物の値と同じであるので、変性ポリビニルアルコール混合物を構成するポリビニルアルコールのそれぞれについてケン化度がわかっている場合はこれを用いることができる。また、ポリビニルアルコール混合物の全体としてのケン化度が８０モル％以上であることにより、アセタール化して得られる本発明２の変性ポリビニルアセタール樹脂の全体としてのケン化度も８０モル％以上となる。
【００６２】
本発明２における上記アセタール化は、上記ポリビニルアルコール混合物の水溶液にアルデヒドを添加し、公知の方法により行うことができる。
本発明２の変性ポリビニルアセタール樹脂のアセタール化度は、アセタール化が１種のアルデヒドで行われた場合及びアセタール化が２種以上混合したアルデヒドで行われた場合のいずれの場合であっても、４０〜８０モル％であることが好ましい。４０モル％未満であると、本発明２の変性ポリビニルアセタール樹脂は水溶性となり、有機溶剤に不溶となる。８０モル％を超えると、残存水酸基数が少なくなり本発明２の変性ポリビニルアセタール樹脂の強靱性が損なわれることがある。なお、上記アセタール化度には、本発明２の変性ポリビニルアセタール樹脂の用途に応じて、より好適な範囲を選定してもよい。
【００６３】
本発明２の変性ポリビニルアセタール樹脂の重合度は特に限定されないが、５０〜３５００であることが好ましい。この範囲であれば、本発明２の変性ポリビニルアセタール樹脂及び変性ポリビニルアルコールを生産性よく製造できる。より好ましくは２００〜３５００である。なお、上記重合度には、本発明２の変性ポリビニルアセタール樹脂の用途に応じて、より好適な範囲を選定してもよい。また、本明細書において、本発明２の変性ポリビニルアセタール樹脂の重合度は、本発明２の変性ポリビニルアセタール樹脂を構成する各成分の重合度に重量比を掛け、その総和を求めたものである。
【００６４】
本発明２の変性ポリビニルアセタール樹脂の水分量は、２．５重量％以下であることが好ましい。２．５重量％を超えると、後述する本発明６の熱現像性感光材料等に用いられた場合に充分な特性を発現できないことがある。上記水分量を２．５重量％以下にする方法としては、アセタール化後の水又は水／アルコールの混合溶液等による洗浄の後に、乾燥により規定の量以下までに除去する方法等が挙げられる。より好ましくは２．０重量％以下である。
【００６５】
本発明２の変性ポリビニルアセタール樹脂のアルデヒド量は、１００ｐｐｍ以下であることが好ましい。１００ｐｐｍを超えると、後述する本発明６の熱現像性感光材料に用いられた場合に充分な特性を発現できないことがある。上記アルデヒド量を１００ｐｐｍ以下にする方法としては、水又は水／アルコールの混合溶液等による洗浄操作にて精製して規定量以下まで除去する方法等が挙げられる。より好ましくは５０ｐｐｍ以下、更に好ましくは１０ｐｐｍ以下である。
【００６６】
本発明２の変性ポリビニルアセタール樹脂を製造する具体的方法としては、例えば、ポリビニルアルコール混合物を溶媒に溶解させ、酸触媒の存在下で、所望のアセタール化度を与えるよう所定量のアルデヒドと反応させた後、アルカリ又は停止剤によりアセタール化反応を停止させ、水洗、乾燥する方法等が挙げられる。
【００６７】
本発明２の変性ポリビニルアセタール樹脂は、主鎖の構成単位としてエチレンをランダムに有し、所定のエチレン含有率及びケン化度を有するポリビニルアルコール混合物をアセタール化したものであり、含有される水酸基の水素結合力が弱まっていることから、溶液にしたときの粘度が低く、その経時安定性に優れ、かつ、柔軟性に優れた塗膜を形成することができるものである。このような本発明２の変性ポリビニルアセタール樹脂は、セラミックス、インク、塗料、接着剤、特殊コーティング、各種バインダー等の分野に効果的に使用できる。
【００６８】
本発明３は、本発明１又は本発明２の変性ポリビニルアセタール樹脂を用いてなるインクである。
本発明３のインクに用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂のアセタール化度は、アセタール化が１種のアルデヒドで行われた場合及びアセタール化が２種以上混合したアルデヒドで行われた場合のいずれの場合であっても、６０〜７５モル％であることがより好ましい。６０モル％未満であると、本発明１又は本発明２の変性ポリビニルアセタール樹脂の親水性が増大して耐水性が充分でないことがある。７５モル％を超えると、残存水酸基数が少なくなり本発明１又は本発明２の変性ポリビニルアセタール樹脂のアルコール系溶剤への溶解性が充分でないことがある。
【００６９】
本発明３のインクに用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂の重合度は特に限定されないが、５０〜３５００であることが好ましい。５０未満であると、原料であるポリビニルアルコールの生産が難しくなることがある。３５００を超えると、本発明３のインクの溶液粘度が高くなりすぎ、分散性が悪く、均一なインクが得られない。より好ましくは５０〜１０００である。
【００７０】
本発明３のインクは、本発明１又は本発明２のポリビニルアセタール樹脂、顔料、有機溶剤等を配合し、これを常法により混合することによって調製することができる。
【００７１】
上記変性ポリビニルアセタール樹脂の配合量は、本発明３のインク全量に対して５〜２５重量％であることが好ましい。５重量％未満であると、インクの塗膜を形成した場合に造膜性に乏しくなることがある。２５重量％を超えると、溶液粘度が高くなり過ぎ顔料の分散性が悪くなることがある。より好ましくは１０〜２０重量％である。
【００７２】
上記顔料としては特に限定されず、例えば、無機系顔料又は有機系顔料が挙げられる。上記無機系顔料としては特に限定されず、例えば、酸化チタン、カーボンブラック等が挙げられる。上記有機系顔料としては特に限定されず、例えば、ジアゾ系顔料、フタロシアニン系顔料等が挙げられる。
【００７３】
上記顔料の配合量は、本発明３のインク全量に対して、濃縮インクとしては１５〜３０重量％が好ましく、希釈されたインク製品としては１０〜１５重量％が好ましい。１０重量％未満では、塗布後のインク濃度が低くなり、目的の色味をだすことができないことがある、３０重量％を超えると、顔料を分散させることができずに凝集することがある。
【００７４】
上記有機溶剤としては、本発明１又は本発明２の変性ポリビニルアセタール樹脂を溶解し、本発明３のインクに適度な混練性を与えるものであれば特に限定されず、例えば、アセトン、メチルエチルケトン等のケトン類；メタノール、エタノール、イソプロパノール、ｎ−プロパノール、ｎ−ブタノール等のアルコール類；トルエン、キシレン等の芳香族炭化水素類；酢酸メチル、酢酸エチル、酢酸ブチル等のエステル類等が挙げられ、なかでも、アルコール系の溶剤が環境保護の観点から好ましい。これらの有機溶剤は、単独で用いられてもよく、２種以上が併用されてもよい。
上記有機溶剤の配合量は、本発明３のインク全量に対して６０〜８５重量％であることが好ましい。
【００７５】
本発明３のインクには、必要に応じて、更に接着促進剤、遅延剤、可塑剤、充填剤、ワックス、相溶化剤、界面活性剤、分散剤、粘着性付与剤等が配合されてもよい。
【００７６】
本発明３のインクは、本発明１又は本発明２の変性ポリビニルアセタール樹脂を用いることにより、ハイソリッド化しても粘度の経時安定性が優れているので、長期間保管しても問題なく使用できる。また、本発明３のインクは、樹脂基材への接着性及び耐湿性に優れ、高湿度環境下での樹脂基材への接着性に優れているので、アイスクリーム、チョコレート等の冷蔵で保管する食品の包装材料の印刷に有効に使用でき、更にガスバリア性に優れ酸素透過度が低いので、食品の保証期間を延ばすこともできる。
【００７７】
本発明４は、本発明１又は本発明２の変性ポリビニルアセタール樹脂を用いてなる塗料である。
本発明４の塗料に用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂のアセタール化度は、アセタール化が１種のアルデヒドで行われた場合及びアセタール化が２種以上混合したアルデヒドで行われた場合のいずれの場合であっても、６０〜７５モル％であることがより好ましい。６０モル％未満であると、本発明１又は本発明２の変性ポリビニルアセタール樹脂の親水性が増大して耐水性が充分でないことがある。７５モル％を超えると、残存水酸基数が少なくなり本発明１又は本発明２の変性ポリビニルアセタール樹脂のアルコール系溶剤への溶解性が充分でないことがある。
【００７８】
本発明４の塗料に用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂の重合度は特に限定されないが、５０〜３５００であることが好ましい。５０未満であると、原料であるポリビニルアルコールの生産が難しくなることがある。３５００を超えると、本発明４の塗料の溶液粘度が高くなりすぎ、分散性が悪く、均一なインクが得られない。より好ましくは５０〜１０００である。
【００７９】
本発明４の塗料は、本発明１又は本発明２のポリビニルアセタール樹脂、顔料、有機溶剤等を配合し、これを常法により混合することによって調製することができる。
【００８０】
上記変性ポリビニルアセタール樹脂の配合量は、本発明４の塗料全量に対して５〜２５重量％であることが好ましい。５重量％未満であると、塗料の塗膜を形成した場合に造膜性に乏しくなることがある。２５重量％を超えると、溶液粘度が高くなり過ぎ顔料の分散性が悪くなることがある。より好ましくは１０〜２０重量％である。
【００８１】
本発明４における上記顔料としては特に限定されず、例えば、無機系顔料又は有機系顔料が挙げられ、本発明３のインクにおける顔料と同様のものを用いることができる。
上記顔料の配合量は、本発明４の塗料全量に対して、濃縮塗料としては１５〜３０重量％が好ましく、希釈された塗料製品としては１０〜１５重量％が好ましい。１０重量％未満では、塗布後の塗料濃度が低くなり、目的の色味をだすことができないことがある、３０重量％を超えると、顔料を分散させることができずに凝集することがある。
【００８２】
本発明４の塗料における上記有機溶剤としては、本発明１又は本発明２の変性ポリビニルアセタール樹脂を溶解し、本発明４の塗料に適度な混練性を与えるものであれば特に限定されず、例えば、本発明３のインクにおける有機溶剤と同様のものを用いることができ、なかでも、アルコール系の溶剤が環境保護の観点から好ましい。これらの有機溶剤は、単独で用いられてもよく、２種以上が併用されてもよい。
上記有機溶剤の配合量は、本発明４の塗料全量に対して６０〜８５重量％であることが好ましい。
【００８３】
本発明４の塗料には、必要に応じて、更に接着促進剤、遅延剤、可塑剤、充填剤、ワックス、相溶化剤、界面活性剤、分散剤、粘着性付与剤等が配合されてもよい。
【００８４】
本発明４の塗料は、本発明１又は本発明２の変性ポリビニルアセタール樹脂を用いることにより、ハイソリッド化しても粘度の経時安定性が優れているので、長期間保管しても問題なく使用できる。また、本発明４の塗料は、樹脂基材への接着性及び耐湿性に優れ、高湿度環境下での樹脂基材への接着性に優れているので、アイスクリーム、チョコレート等の冷蔵で保管する食品の包装材料の印刷に有効に使用でき、更にガスバリア性に優れ酸素透過度が低いので、食品の保証期間を延ばすこともできる。
【００８５】
本発明５は、本発明１又は本発明２の変性ポリビニルアセタール樹脂と、フェノール樹脂、エポキシ樹脂及びメラミン樹脂からなる群より選択される少なくとも１種の熱硬化性樹脂とを含有する接着剤である。
本発明５の接着剤に用いられる場合における本発明の変性ポリビニルアセタール樹脂のアセタール化度は、アセタール化が１種のアルデヒドで行われた場合及びアセタール化が２種以上混合したアルデヒドで行われた場合のいずれの場合であっても、６０〜８０モル％であることがより好ましい。６０モル％未満であると、本発明１又は本発明２の変性ポリビニルアセタール樹脂の親水性が増大して耐水性が充分でないことがある。８０モル％を超えると、残存水酸基数が少なくなり本発明１又は本発明２の変性ポリビニルアセタール樹脂の強靱性が損なわれたり、熱硬化性樹脂との反応性が低下したりすることがある。
【００８６】
本発明５の接着剤に用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂の重合度は特に限定されないが、１０００〜３５００であることがより好ましい。１０００未満であると、接着後の引き剥がし強度が低下することがあり、３５００を超えると、接着剤溶液の粘度が高くなりすぎるため塗工性が悪く、均一な接着剤組成物を得ることができない。更に好ましくは１５００〜３０００である。
【００８７】
本発明５の接着剤における本発明１又は本発明２の変性ポリビニルアセタール樹脂と上記熱硬化性樹脂との配合比は、重量比で、３：９７〜７０：３０であることが好ましい。本発明１又は本発明２の変性ポリビニルアセタール樹脂の配合比が３未満であると、銅箔への接着性が低下することがあり、７０を超えると、耐熱性が悪くなることがある。なかでも、上記熱硬化性樹脂の主成分がフェノール樹脂及び／又はメラミン樹脂である場合には、重量比で、３０：７０〜７０：３０であることがより好ましく、上記熱硬化性樹脂の主成分がエポキシ樹脂である場合には、重量比で、３：９７〜３０：７０であることがより好ましい。
【００８８】
本発明５の接着剤を調製するのに用いられる溶剤としては特に限定されず、例えば、アセトンメチルエチルケトン等のケトン類；メタノール、エタノール及びブタノール等のアルコール類；トルエン及びキシレン等の芳香族炭化水素類等が適宜用いられる。
【００８９】
本発明５の接着剤は、耐熱性の向上等の目的に応じて、上記以外の熱硬化性樹脂、硬化剤、酸化防止剤、消泡剤、帯電防止剤等の添加剤を含有していてもよい。
【００９０】
本発明５の接着剤は、本発明１又は本発明２の変性ポリビニルアセタール樹脂を含有することにより、本発明１又は本発明２の変性ポリビニルアセタール樹脂が熱硬化性樹脂との反応性が高く、吸湿性に優れているため、耐熱性及び接着強度に優れたものであり、特に耐熱接着強度に優れたものである。本発明５の接着剤は、例えば、プリント回路基板の積層板の接着剤として用いれば、耐熱性、特にハンダ耐熱性及び引き剥がし強度を大幅に改善することができ、得られた接着剤付き銅箔は、高湿度の環境下に長時間放置されても、ハンダ耐熱性及び引き剥がし強度に優れたものとなる。
【００９１】
本発明６は、本発明１又は本発明２の変性ポリビニルアセタール樹脂を用いてなる熱現像性感光材料である。
本発明６の熱現像性感光材料に用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂は、アセトアルデヒド及び／又はブチルアルデヒドによりアセタール化されたものであることが特に好ましく、これにより、本発明６の熱現像性感光材料は、画像特性のバランスが取りやすいものとなる。
【００９２】
本発明６の熱現像性感光材料に用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂のアセタール化度は、アセタール化が１種のアルデヒドで行われた場合及びアセタール化が２種以上混合したアルデヒドで行われた場合のいずれの場合であっても、６５〜８０モル％であることがより好ましい。６５モル％未満であると、本発明１又は本発明２の変性ポリビニルアセタール樹脂の水酸基量が多いために親水性のバランスが取りにくくなり、画像形成後のフィルム保存時に有機酸が結晶物質を作り、塗膜表面が白っぽくなる等の問題を生じることがある。８０モル％を超えると、残存水酸基数が少なくなり本発明１又は本発明２の変性ポリビニルアセタール樹脂の強靱性が損なわれて塗膜強度が低下したり、ハロゲン化銀の分散性が悪くなって画像特性等が悪くなったりすることがある。
【００９３】
本発明６の熱現像性感光材料に用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂の重合度は特に限定されないが、２００〜３０００であることがより好ましい。更に好ましくは、本発明６の熱現像性感光材料に用いられる銀塩の分散性、塗膜強度、塗工性等のバランスを取りやすい２００〜１０００である。
【００９４】
本発明６の熱現像性感光材料に用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂の残存アセチル基の量は、２５モル％以下であることが好ましい。２５モル％を超えると、得られる感光性フィルム同士のブロッキングが生じたり、画像が鮮明でなくなったりすることがある。より好ましくは１５モル％以下である。
【００９５】
本発明６の熱現像性感光材料に用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂の水分量は、２．５重量％以下であることが好ましい。２．５重量％を超えると、塗工溶液のポットライフが低下したり、塗膜強度を向上するために添加される架橋剤、例えば、イソシアナト基を含有する化合物と反応して充分な塗膜強度が得られなかったり、水と反応することを見込んで架橋剤の添加量を増やした際にかぶり等の原因になったりすることがある。上記水分量を２．５重量％以下にする方法としては、アセタール化後の水又は水／アルコールの混合溶液等による洗浄の後に、乾燥により規定の量以下までに除去する方法等が挙げられる。より好ましくは２．０重量％以下である。
【００９６】
本発明６の熱現像性感光材料に用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂のアルデヒド量は、１００ｐｐｍ以下であることが好ましい。１００ｐｐｍを超えると、塗工溶液中に含まれる還元剤によりアルデヒドが還元され、塗工溶液の保存性を低下させ、フィルムの生保存性の低下、かぶり等の原因になることがある。上記アルデヒド量を１００ｐｐｍ以下にする方法としては、水又は水／アルコールの混合溶液等による洗浄操作にて精製して規定量以下まで除去する方法等が挙げられる。より好ましくは５０ｐｐｍ以下、更に好ましくは１０ｐｐｍ以下である。
【００９７】
なお、本発明６の熱現像性感光材料に用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂の製造においては、ヒンダードフェノール系、ビスフェノール系及びリン酸系等の酸化防止剤は使用しないことが好ましい。通常、変性ポリビニルアルコールとアルデヒドとのアセタール化反応においては、アルデヒドの酸化防止のため、又は、得られる変性ポリビニルアセタール樹脂の酸化防止及び耐熱性向上のために、反応系又は樹脂系に酸化防止剤が添加されるが、上記酸化防止剤を使用すると、本発明１又は本発明２の変性ポリビニルアセタール樹脂中に残存し、塗工溶液のポットライフの低下、生フィルムの生保存性の低下を引き起こし、かぶりや画像／階調部の鮮明性が損なわれることがある。
【００９８】
本発明６の熱現像性感光材料の配合は、本発明１又は本発明２の変性ポリビニルアセタール樹脂を用いること以外は、従来の熱現像性感光材料の配合と変わらず、例えば、本発明１又は本発明２の変性ポリビニルアセタール樹脂に、有機銀塩、還元剤、必要に応じて少量の感光性ハロゲン化銀又はハロゲン化銀形成成分、架橋剤、増感剤等が配合され、銀により黒色画像を形成させる場合には更に色調剤が配合されてもよく、カラー画像を形成させる場合には更にカラーカプラー、ロイコ染料等が配合されてもよい。
【００９９】
本発明１又は本発明２の変性ポリビニルアセタール樹脂の配合量は、重量比で、有機銀塩に対して１：１０〜１０：１であることが好ましく、より好ましくは１：５〜５：１である。
【０１００】
上記有機銀塩は、光に比較的安定な無色又は白色の銀塩である。
上記有機銀塩としては、感光したハロゲン化銀の存在下で８０℃以上に加熱されたときに還元剤と反応して銀を生じるものであれば特に限定されず、例えば、メルカプト基、チオン基又はカルボキシル基を有する有機化合物の銀塩；ベンゾトリアゾール銀等が挙げられる。具体的には、メルカプト基又はチオン基を有する化合物の銀塩、３−メルカプト−４−フェニル１，２，４−トリアゾールの銀塩、２−メルカプト−ベンツイミダゾールの銀塩、２−メルカプト−５−アミノチアゾールの銀塩、１一フェニル−５−メルカプトテトラチアゾールの銀塩、２−メルカプトペンゾチアゾールの銀塩、チオグリコール酸の銀塩、ジチオ酢酸の銀塩等のジチオカルボン酸の銀塩、チオアミド銀、チオピリジン銀塩、メルカプトオキサジアゾールの銀塩、メルカプトトリアジンの銀塩、脂肪族カルボン酸の銀塩；カプリン酸銀、ラウリル酸銀、ミリスチン酸銀、パルミチン酸銀、ステアリン酸銀、ベヘン酸銀、マレイン酸銀、フマル酸銀、酒石酸銀、フロイン酸銀、リノール酸銀、オレイン酸銀、ヒドロキシステアリン酸銀、アジピン酸銀、セバシン酸銀、コハク酸銀、酢酸銀、酪酸銀、樟脳酸銀等、芳香族カルボン酸銀、チオンカルボン酸銀、チオエーテル基を有する脂肪族カルボン酸銀、テトラザインデンの銀塩、Ｓ−２−アミノフェニルチオ硫酸銀、含金属アミノアルコール、有機酸金属キレート等が挙げられる。なかでも、脂肪族カルボン酸の銀塩が好ましく、より好ましくはベヘン酸銀である。
上記有機銀塩の粒子径は、０．０１〜１０μｍであることが好ましく、より好ましくは０．１〜５μｍである。
【０１０１】
上記有機銀塩には、感光性ハロゲン化銀を触媒的に接触させてもよい。
上記感光性ハロゲン化銀としては特に限定されず、例えば、臭化銀、ヨウ化銀、塩化銀、塩臭化銀、ヨウ臭化銀、塩ヨウ化銀等が挙げられる。
上記有機銀塩に感光性ハロゲン化銀を触媒的に接触させる方法としては特に限定されず、例えば、予め調整した有機銀塩の溶液や分散液に、又は、有機銀塩を含むフィルム材料に、ハロゲン化銀形成成分を作用させて有機銀の一部をハロゲン化銀に形成する方法等が挙げられる。
上記感光性ハロゲン化銀形成成分としては、有機銀塩に作用してハロゲン化銀を形成するものであれば特に限定されないが、ヨウ素イオンを含むものであることが好ましい。
上記感光性ハロゲン化銀の配合量は、有機銀塩１００重量部に対して０．０００５〜０．２重量部であることが好ましく、より好ましくは０．０１〜０．２重量部である。
【０１０２】
上記還元剤としては特に限定されず、併用される有機銀塩に応じて適宜選択され、例えば、置換フェノール類、ビスフェノール類、ナフトール類、ビスナフトール類、ポリヒドロキシベンゼン類、ジ又はポリヒドロキシナフタレン類、ハイドロキノンモノエーテル類、アスコルビン酸又はその誘導体、還元性糖類、芳香族アミノ化合物、ヒドロキシアミン類、ヒドラジン類、フェニドン類、ヒドロキノン類、ヒンダードフェノール類等が挙げられ、光分解性のものと熱分解性のものがある。なかでも、光分解性の還元剤が好ましく、特にヒンダードフェノール類が好ましい。
【０１０３】
上記還元剤の配合量は、有機銀塩１００重量部に対して０．０００１〜３．０重量部であることが好ましく、より好ましくは０．０１〜１．０重量部である。
上記還元剤には、光分解を促進する化合物を併用してもよく、ハロゲン化銀と還元剤との反応を阻害するための被覆剤を併用してもよい。
【０１０４】
本発明６の熱現像性感光材料を製造する方法としては、例えば、本発明１又は本発明２の変性ポリビニルアセタール樹脂、有機銀塩、還元剤及び溶剤をボールミルで分散させた後に、必要に応じて、更にハロゲン化銀又はハロゲン化銀形成成分、各種添加剤を加えボールミルで分散させ、得られた分散液を支持体上に有機銀塩が規定の量となるように塗布し、溶剤を蒸発させる方法等が挙げられる。なお、上記有機銀塩と還元剤とは、これらを一括して本発明１又は本発明２の変性ポリビニルアセタール樹脂に配合し、これを支持体上に１層にして形成してもよいが、上記有機銀塩と還元剤とを各々別に本発明１又は本発明２の変性ポリビニルアセタール樹脂に配合して、これらを支持体上に各々別に２層にして形成してもよい。
【０１０５】
上記溶剤としては、本発明１又は本発明２の変性ポリビニルアセタール樹脂を溶解することができ、水分をほとんど含有しないものが好適に用いられる。なかでも、ケトン、エステル類が好ましく、より好ましくはジエチルケトン、メチルエチルケトン、メチル−ｉｓｏ−ブチルケトン、酢酸メチル、酢酸エチル、酢酸プロピル等である。
【０１０６】
上記支持体としては、例えば、ポリエチレンテレフタレート、ポリカーボネート、ポリエチレン、ポリプロピレン、ポリビニルアセタール、セルロースエステル、セルロースジアセテート、セルローストリアセテート、ニトロセルロース、ポリエチレンナフタレート、塩化ビニル、塩素化ポリプロピレン等の樹脂フィルム；ガラス；紙；アルミニウム板等の金属板等が用いられる。
【０１０７】
上記支持体上に塗布される銀の量は、支持体１ｍ^２あたり０．１〜５．０ｇであることが好ましい。０．１ｇ未満であると、画像濃度が低くなることがあり、５．０ｇを超えると、画像濃度の向上がみられなくなる。より好ましくは０．３〜３．０ｇである。なお、塗布は両面又は片面のいずれでもよい。
【０１０８】
本発明６の熱現像性感光材料は、長期間保管してもブロッキングの問題がなく、水分の吸湿の影響による生フィルム保存性の低下、かぶりを抑えることができ、親水性のバランスを保つことにより、画像形成後のフィルムの保存性等に優れており、優れた画像特性を示す。
【０１０９】
本発明７は、本発明１又は本発明２の変性ビニルアセタール樹脂、セラミックス粉末、可塑剤、及び、有機溶剤を含有するセラミックスグリーンシート用スラリー組成物である。
本発明７のセラミックスグリーンシート用スラリー組成物に用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂のアセタール化度は、アセタール化が１種のアルデヒドで行われた場合及びアセタール化が２種以上混合したアルデヒドで行われた場合のいずれの場合であっても、４０〜７９モル％であることがより好ましい。４０モル％未満であると、本発明１又は本発明２の変性ポリビニルアセタール樹脂が水溶性となり、有機溶剤に不溶となる。７９モル％を超えると、残存水酸基数が少なくなり本発明１又は本発明２の変性ポリビニルアセタール樹脂の強靱性が損なわれ、グリーンシートの強度が低下することがある。
【０１１０】
本発明７のセラミックスグリーンシート用スラリー組成物に用いられる場合における本発明１又は本発明２の変性ポリビニルアセタール樹脂の重合度は特に限定されないが、３００〜２４００であることがより好ましい。３００未満であると、セラミックスグリーンシートに成形したときの強度が低く、支持体からの剥離の際にセラミックスグリーンシートが切れたり、クラックが入ったりしやすく、２４００を超えると、スラリーの溶液粘度が高くなりすぎるために分散性が悪く、均一なスラリーを得ることができない。
【０１１１】
本発明１又は本発明２の変性ポリビニルアセタール樹脂の配合量は、本発明７のセラミックスグリーンシート用スラリー組成物全量に対して３〜１５重量％であることが好ましい。３重量％未満であると、セラミックス粉末全体に分散される本発明１又は本発明２の変性ポリビニルアセタール樹脂の量が不充分となり、得られるセラミックスグリーンシートの柔軟性が不充分で、焼結後にクラック等が発生することがある。１５重量％を超えると、本発明７のセラミックスグリーンシート用スラリー組成物の粘度が高くなり過ぎて分散性が低下したり、得られたセラミックスグリーンシートを焼成する際にシートの収縮率が大きくなったりする。
【０１１２】
上記セラミックス粉末としては特に限定されず、従来セラミックスグリーンシートを製造するのに用いられていたセラミックス粉末が挙げられる。このようなセラミックス粉末としては、例えば、アルミナ、ジルコニア、ケイ酸アルミニウム、酸化チタン、酸化亜鉛、チタン酸バリウム、マグネシア、サイアロン、スピネルムライト、結晶化ガラス、炭化ケイ酸、窒化ケイ酸、窒化アルミニウム等からなる粉末が挙げられる。これらのセラミックス粉末は単独で用いられてもよく、２種以上併用されてもよい。
【０１１３】
また、これらのセラミックス粉末には、ＭｇＯ−ＳｉＯ_２−ＣａＯ系、Ｂ_２Ｏ_３−ＳｉＯ_２系、ＰｂＯ−Ｂ_２Ｏ_３−ＳｉＯ_２系、ＣａＯ−ＳｉＯ_２−ＭｇＯ−Ｂ_２Ｏ_３系又はＰｂＯ−ＳｉＯ_２−Ｂ_２Ｏ_３−ＣａＯ系等のガラスフリットを添加してもよい。
【０１１４】
上記セラミックス粉末の粒子径は、微細であることが好ましく、薄層のセラミックスグリーンシートを得るためには、特に微細な粒子径のセラミックス粉末を用いることが好ましい。例えば、３μｍ以下のセラミックスグリーンシートを得るためには、上記セラミックス粉末の粒子径は０．３μｍ以下であることが好ましい。
【０１１５】
上記セラミックス粉末の配合量は、本発明７のセラミックスグリーンシート用スラリー組成物全量に対して３０〜８０重量％であることが好ましい。３０重量％未満であると、本発明７のセラミックスグリーンシート用スラリー組成物の粘度が低くなり過ぎてセラミックスグリーンシートを成形する際のハンドリング性が悪くなることがある。８０重量％を超えると、本発明７のセラミックスグリーンシート用スラリー組成物の粘度が高くなり過ぎて混練性が低下することがある。
【０１１６】
上記可塑剤としては特に限定されず、本発明１又は本発明２の変性ポリビニルアセタール樹脂との相溶性に優れているものであれば、任意の可塑剤を用いることができる。例えば、フタル酸ジブチル、フタル酸ジオクチル、フタル酸ジイソデシル、フタル酸ブチルベンジル等のフタル酸エステル系；リン酸トリクレジル、リン酸トリブチル、リン酸トリエチル等のリン酸エステル系；リシノール酸メチルアセチル、セバシン酸ジブチル、アジピン酸ジオクチル等の脂肪酸エステル系；ブチルフタリルグリコレート、トリエチレングリコール−２−エチルブチレート等のグリコール誘導体等が挙げられる。これらの可塑剤は、単独で用いられてもよく、２種以上が併用されてもよい。
【０１１７】
上記可塑剤の配合量は、本発明７のセラミックスグリーンシート用スラリー組成物全量に対して０．１〜１０重量％であることが好ましい。０．１重量％未満であると、可塑剤を配合したことによるセラミックスグリーンシートの柔軟性が充分に得られない。１０重量％を超えると、セラミックスグリーンシートが柔らかくなりすぎてセラミックスグリーンシートを成形する際のハンドリング性が悪くなることがある。
【０１１８】
上記有機溶剤としては特に限定されず、例えば、アセトン、メチルエチルケトン等のケトン類；メタノール、エタノール、イソプロパノール、ｎ−プロパノール、ｎ−ブタノール等のアルコール類；トルエン、キシレン等の芳香族炭化水素類等が挙げられる。これらの有機溶剤は、単独で用いられてもよく、２種以上が併用されてもよい。
【０１１９】
上記有機溶剤の配合量は、本発明７のセラミックスグリーンシート用スラリー組成物全量に対して２０〜８０重量％であることが好ましい。この範囲であれば、本発明１又は本発明２の変性ポリビニルアセタール樹脂を溶解し、本発明７のセラミックスグリーンシート用スラリー組成物に適度な混練性を与えることができる。
【０１２０】
本発明７のセラミックスグリーンシート用スラリー組成物には、本発明７の目的を達成し得る範囲内で、必要に応じて、潤滑剤、分散剤、解膠剤、濡れ剤、帯電防止剤、消泡剤等を含有させてもよい。
【０１２１】
本発明７のセラミックスグリーンシート用スラリー組成物は、本発明１又は本発明２の変性ポリビニルアセタール樹脂、セラミックス粉末、可塑剤及び有機溶剤を配合し、これを常法により混合することで調製することができる。
【０１２２】
本発明７のセラミックスグリーンシート用スラリー組成物をシート状に賦形して乾燥することによりセラミックスグリーンシートを得ることができる。例えば、本発明７のセラミックスグリーンシート用スラリー組成物を、必要に応じて脱泡した後、剥離性のポリエステルフィルム、ステンレス鋼のプレート等の支持体上に塗布し、加熱、乾燥により有機溶剤を除去し、その後支持体から剥離する。このような本発明７のセラミックスグリーンシート用スラリー組成物を用いてなるセラミックスグリーンシートもまた本発明の１つである。
【０１２３】
本発明のセラミックスグリーンシートを用いることにより、積層セラミックスコンデンサを得ることができる。上記積層セラミックスコンデンサは、本発明のセラミックスグリーンシート上に内部電極となる導電ペーストをスクリーン印刷等により塗布したものを複数枚積み重ね、加熱圧着して積層体を作製し、この積層体を所定の形状及び寸法に切断した後、例えば６００℃程度の高温に加熱してバインダー樹脂として用いられている本発明１又は本発明２のポリビニルアセタール樹脂をほぼ完全に分解し、更に例えば１３５０℃程度の高温に加熱してセラミックス粉末を焼結し、次いで得られたセラミックス焼結体の端面に外部電極を焼結することにより得られる。
【０１２４】
本発明７のセラミックスグリーンシート用スラリー組成物は、バインダー樹脂として本発明１又は本発明２のポリビニルアセタール樹脂を含有しており、変性ポリビニルアセタール樹脂の水素結合力が立体障害的に弱められているため、バインダー樹脂として未変性ポリビニルアセタール樹脂のみを使用した場合に比べて低粘度で粘度の経時安定性に優れている。これにより、使用溶剤量を減らしてハイソリッド化することができ、スラリーの長期保管も可能となる。
【０１２５】
本発明のセラミックスグリーンシートは、本発明７のセラミックスグリーンシート用スラリー組成物が可塑剤を過剰に含有する必要がないので、シート強度、特に伸度が大幅に向上し、支持体から剥離しやすくかつ圧着時の接着性に優れた積層時における接着性のバランスが良好なものである。また、本発明のセラミックスグリーンシートは吸湿性が低いので、セラミックスグリーンシートの状態で長期間保管することができ、打ち抜き等の加工をしたりする際に湿度の影響を受けにくい。従って、厚みが３μｍ以下の薄層セラミックスグリーンシートであっても湿度の影響を受けずに成形でき、セラミックスグリーンシートを損傷することなく積層できる。更に、本発明のセラミックスグリーンシートは、含有する本発明１又は本発明２の変性ポリビニルアセタール樹脂が熱分解性に優れ熱分解残渣が非常に少ないため、厚さが３μｍ以下の薄層セラミックスグリーンシートを５００層以上積み重ねた積層体を焼結した場合においても、焼結後のセラミックスグリーンシート内にバインダーの熱分解残渣がなく、電気特性に優れた積層体を得ることができる。したがって、積層セラミックスコンデンサ等の電子部品の小型化への対応ができるとともに、ガラスパウダーを使用したり、電極に銅を使用したりするような低温での脱バインダー性を要求されるＬＴＣＣ（低温焼結基板）等にも対応できる。また、本発明のセラミックスグリーンシートは、本発明１又は本発明２の変性ポリビニルアセタール樹脂が単量体単位としてエチレン単位を含有していることにより、可塑剤との相溶性が飛躍的に向上しており、可塑剤のブリードアウトを抑制し、セラミックスグリーンシートを長期間保存することができ、焼結時の収縮率も小さいため寸法安定性等も向上し、部品の小型化に対応できる。
【０１２６】
【実施例】
以下に実施例を掲げて本発明を更に詳しく説明するが、本発明はこれら実施例のみに限定されるものではない。
【０１２７】
（実施例１）
＜変性ポリビニルアセタール樹脂の製造＞
重合度８００、エチレン含有率５モル％、ケン化度９３モル％の主鎖の構成単位としてエチレンをランダムに有する変性ポリビニルアルコール１９３ｇを純水２９００ｇに加え、９０℃の温度で約２時間攪拌して溶解させた。この溶液を２８℃に冷却し、これに濃度３５重量％の塩酸２０ｇとｎ−ブチルアルデヒド１１５ｇとを添加し、液温を２０℃に下げてこの温度を維持してアセタール化反応を行い、反応生成物を析出させた。その後、液温を３０℃に５時間維持して反応を完了させ、常法により中和、水洗及び乾燥を行い、変性ポリビニルアセタール樹脂の白色粉末を得た。
【０１２８】
得られた変性ポリビニルアセタール樹脂をＤＭＳＯ−ｄ_６（ジメチルスルホキサイド）に溶解し、^１３Ｃ−ＮＭＲ（核磁気共鳴スペクトル）を用いてアセタール化度を測定したところ、アセタール化度は６８モル％であった。また、示差走査熱量計によりガラス転移温度を測定したところ、ガラス転移温度は１つのみ現れ、エタノール／トルエン＝１／１（重量比）の混合液、及び、メチルエチルケトンに完全に溶解したことから、変性ポリビニルアセタール樹脂が主鎖の構成単位としてエチレンをランダムに有するものであることが確認できた。
【０１２９】
（実施例２〜４）
ポリビニルアルコールの重合度、エチレン含有率、ケン化度、アルデヒドの種類、アセタール化度を表１に示したように変更したこと以外は実施例１と同様の方法により、変性ポリビニルアセタール樹脂を得た。なお、実施例４は変性ポリビニルアルコール／未変性ポリビニルアルコール＝１／１（重量比）の混合物を用いた。得られた変性ポリビニルアセタール樹脂について示差走査熱量計によりガラス転移温度を測定したところ、含有される１種の変性ポリビニルアセタールに対応するガラス転移温度は１つのみ現れ、エタノール／トルエン＝１／１（重量比）の混合液、及び、メチルエチルケトンに完全に溶解したことから、変性ポリビニルアセタール樹脂が主鎖の構成単位としてエチレンをランダムに有するものであることが確認できた。
【０１３０】
（比較例１〜４）
エチレンを単量体単位として含まないことの他は実施例１〜４で用いた変性ポリビニルアルコールと同じ構造を有する未変性ポリビニルアルコールを用いたこと以外は、対応する実施例１〜４と同様にしてほぼ同じアセタール化度を有するポリビニルアセタール樹脂を得た。
【０１３１】
【表１】

【０１３２】
＜性能評価＞
実施例１〜４及び比較例１〜４で得られたポリビニルアセタール樹脂の酸素透過係数及び熱分解性を以下の方法により評価し、結果を表２及び表３に示した。
【０１３３】
（酸素透過係数測定）
ポリビニルアセタール樹脂をエタノール／トルエン＝１：１（重量比）の混合溶液に添加し、樹脂濃度が１５重量％となるよう溶解した。次にこの溶液をポリエチレンテレフタレート（以下、ＰＥＴともいう）フィルムに塗布し、５０℃、６時間乾燥後、５０μｍの膜厚を持つポリビニルアセタールフィルムを得た。次に室温において、このポリビニルアセタールフィルムの減圧乾燥処理を６日間実施し測定に供した。測定には、差圧式ガス透過率測定システムを用い、試験ガスに酸素ガスを用い、試験ガス圧力１５Ｎ／ｃｍ^２、試験温度２５℃、ガス透過面積１５．２ｃｍ^２で測定し、酸素透過係数を求めた。
【０１３４】
（熱分解性測定）
測定温度範囲３０〜７００℃、昇温温度１０℃／ｍｉｎで、試験容器として白金パンを開放状態で用い、エアーフロー雰囲気及び窒素フロー雰囲気でそれぞれフロー速度を２００ｍｌ／ｍｉｎにしてＴｇ／ＤＴＡ測定を行った。
【０１３５】
【表２】

【０１３６】
【表３】

【０１３７】
表２の結果より、酸素透過係数において、実施例１〜４で得られたポリビニルアセタール樹脂は、比較例１〜４で得られたポリビニルアセタール樹脂よりも値が低く、酸素をより通しにくいことを示している。すなわち、変性ポリビニルアセタール樹脂は、未変性ポリビニルアセタール樹脂よりもガスバリア性が向上していることがわかる。
【０１３８】
表３の結果より、熱分解性において、実施例１〜４で得られたポリビニルアセタール樹脂は、重量変化率から７００℃でほぼ完全に熱分解していた。一方、比較例１〜４で得られたポリビニルアセタール樹脂は、実施例１〜４で得られたポリビニルアセタール樹脂よりも重量変化率が小さかった。すなわち、変性ポリビニルアセタール樹脂は、未変性ポリビニルアセタール樹脂よりも熱分解性が向上していることがわかる。
【０１３９】
（実施例５〜１１）
ポリビニルアルコールの重合度、エチレン含有率、ケン化度、アルデヒドの種類、アセタール化度を表４に示したように変更したこと以外は実施例１と同様にして変性ポリビニルアセタール樹脂を得た。なお、実施例９〜１１では変性ポリビニルアルコール／未変性ポリビニルアルコール＝１／１（重量比）の混合物を用いた。得られた変性ポリビニルアセタール樹脂について示差走査熱量計によりガラス転移温度を測定したところ、含有される１種の変性ポリビニルアセタールに対応するガラス転移温度は１つのみ現れ、エタノール／トルエン＝１／１（重量比）の混合液、及び、メチルエチルケトンに完全に溶解したことから、変性ポリビニルアセタール樹脂が主鎖の構成単位としてエチレンをランダムに有するものであることが確認できた。
【０１４０】
（比較例５〜１１）
エチレンを単量体単位として含まないことの他は実施例５〜１１で用いた変性ポリビニルアルコールと同じ構造を有する未変性ポリビニルアルコールを用いたこと以外は、対応する実施例５〜１１と同様にして同じアセタール化度を有するポリビニルアセタール樹脂を得た。
【０１４１】
＜性能評価＞
実施例５〜１１及び比較例５〜１１で得られたポリビニルアセタール樹脂の溶液粘度、溶液粘度の経時安定性（粘度変化率）及び塗膜の伸度等の性能を以下の方法で評価し、結果を表４及び表５に示した。
【０１４２】
（溶液粘度及び粘度の差）
実施例５〜１１及び比較例５〜１１で得られたポリビニルアセタール樹脂をエタノール／トルエン＝１／１（重量比）の混合溶液に添加し、樹脂濃度が１０重量％になるように完全に溶解した。次に、この溶液の粘度をブルックフィールドタイプの回転粘度計を使用して２０℃で測定した（初期粘度）。
次に、実施例５で得られた変性ポリビニルアセタール樹脂の溶液粘度と、実施例５に対応する比較例５で得られた未変性ポリビニルアセタール樹脂の溶液粘度を比較し、下記式（３）により粘度の差（の割合）を求めた。
【０１４３】
【数３】

【０１４４】
式（３）中、Ａは、変性ポリビニルアセタール樹脂（実施例５）の粘度を表し、Ｂは、未変性ポリビニルアセタール樹脂（比較例５）の粘度を表す。
【０１４５】
同様にして、実施例６〜１１で得られた変性ポリビニルアセタール樹脂の溶液粘度と、実施例６〜１１にそれぞれ対応する比較例６〜１１で得られた未変性ポリビニルアセタール樹脂の溶液粘度とを比較して粘度の差を求めた。
【０１４６】
（溶液粘度の経時安定性（粘度変化率））
上記初期粘度を測定した溶液を２０℃の恒温室に１ケ月間保管し、保管後の粘度を、ブルックフィールドタイプの回転粘度計を使用して２０℃で測定し、粘度変化率を下記式（４）により求めた。
【０１４７】
【数４】

【０１４８】
式（４）中、Ｃは、１ケ月後の粘度を表し、Ｄは、初期粘度を表す。
【０１４９】
（塗膜の伸度及び伸度の差）
実施例５〜１１及び比較例５〜１１で得られたポリビニルアセタール樹脂を用いてキャスティングにより厚み５０μｍのフィルムを作製した。これを引っ張り速度１０ｍｍ／ｍｉｎで引っ張り、オートグラフ（島津製作所社製）を使用して２０℃における最大点伸度を測定した。
次に、実施例５で得られた変性ポリビニルアセタール樹脂の最大点伸度と、実施例５に対応する比較例５で得られた未変性ポリビニルアセタール樹脂の最大点伸度を比較し、下記式（５）により伸度の差（の割合）を求めた。
【０１５０】
【数５】

【０１５１】
式（５）中、Ｅは、変性ポリビニルアセタール樹脂（実施例５）の最大点伸度を表し、Ｆは、未変性ポリビニルアセタール樹脂（比較例５）の最大点伸度を表す。
【０１５２】
以下、同様にして、実施例６〜１１で得られた変性ポリビニルアセタール樹脂の最大点伸度と、実施例６〜１１にそれぞれ対応する比較例６〜１１で得られた未変性ポリビニルアセタール樹脂の最大点伸度を比較して伸度の差（の割合）を求めた。
【０１５３】
【表４】

【０１５４】
【表５】

【０１５５】
表４及び表５の結果より、比較例５〜１１で得られた未変性ポリビニルアセタール樹脂は、粘度変化率が実施例５〜１１で得られた変性ポリビニルアセタール樹脂に比べ大幅に上昇している。すなわち、未変性ポリビニルアセタール樹脂は粘度安定性が悪いことがわかる。また、粘度の差より、変性ポリビニルアセタール樹脂は、未変性のポリビニルアセタール樹脂に比べ溶液粘度が大幅に低いことがわかる。また、塗膜の伸度の差より、変性ポリビニルアセタール樹脂は未変性のポリビニルアセタール樹脂に比べ伸度が大幅に大きくなっており、柔軟性に優れていることがわかる。
【０１５６】
（実施例１２）
＜変性ポリビニルアセタール樹脂の製造＞
重合度２０００、エチレン含有率５モル％、ケン化度９８モル％の主鎖の構成単位としてエチレンをランダムに有する変性ポリビニルアルコール１９３ｇを純水２９００ｇに加え、９０℃の温度で約２時間攪拌して溶解した。この溶液を２８℃に冷却し、これに濃度３５重量％の塩酸２０ｇを添加し、更にアセトアルデヒド５１ｇを添加した。次に１２℃まで冷却し、ｎ−ブチルアルデヒド４８ｇを添加してアセタール化反応を行い、反応生成物を析出させた。その後、液温を６０℃に５時間維持して反応を完了させ、常法により中和、水洗及び乾燥を行い、変性ポリビニルアセタール樹脂の白色粉末を得た。
【０１５７】
得られた変性ポリビニルアセタール樹脂をＤＭＳＯ−ｄ_６に溶解し、^１３Ｃ−ＮＭＲを用いてアセタール化度を測定したところ、アセトアセタール化度が４３モル％であり、ブチラール化度が３０モル％であり、合計したアセタール化度は７３モル％であった。また、示差走査熱量計によりガラス転移温度を測定したところ、ガラス転移温度は１つのみ現れ、エタノール／トルエン＝１／１（重量比）の混合液、及び、メチルエチルケトンに完全に溶解したことから、変性ポリビニルアセタール樹脂が主鎖の構成単位としてエチレンをランダムに有するものであることが確認できた。
【０１５８】
＜接着剤組成物の調製＞
上記変性ポリビニルアセタール樹脂４０ｇ、フェノール樹脂（群栄化学社製、商品名；ＰＬ−２２０５）６２ｇ及びエポキシ樹脂（シェル化学社製、商品名；エピコート８２８）４ｇをメタノール／メチルエチルケトン／トルエン（重量比＝２：２：１）の混合溶剤２５８ｇに溶解させ、接着剤組成物を調製した。
【０１５９】
次に、得られた接着剤組成物をプリント回路基板用銅箔に固形分としての厚さが３３μｍになるように塗布し、１４０℃で４分間乾燥して接着剤層付き銅箔を得た。この接着剤層付き銅箔を温度２０℃、湿度７０％の条件に３日間放置した。その後、上記接着剤層付き銅箔とフェノール含浸紙とを１５０℃で３０分間、１２００Ｎ／ｃｍ^２の圧力で加圧成形し、銅箔積層板を積層した。
【０１６０】
（実施例１３〜１４、比較例１２〜１３）
変性ポリビニルアルコールの重合度、エチレン含有率、ケン化度、アルデヒドの種類、アセタール化度を表６に示したように変更したこと以外は実施例１２と同様にして接着剤組成物を作製し、これを用いて銅箔積層板を積層した。実施例１３及び１４で得られた変性ポリビニルアセタール樹脂について示差走査熱量計によりガラス転移温度を測定したところ、含有される１種の変性ポリビニルアセタールに対応するガラス転移温度は１つのみ現れ、エタノール／トルエン＝１／１（重量比）の混合液、及び、メチルエチルケトンに完全に溶解したことから、変性ポリビニルアセタール樹脂が主鎖の構成単位としてエチレンをランダムに有するものであることが確認できた。
【０１６１】
（実施例１５）
＜接着剤組成物の調製＞
実施例１２で作製した主鎖の構成単位としてエチレンをランダムに有する変性ポリビニルアセタール樹脂４０ｇ、メラミン樹脂（三井化学社製、商品名；ユーバン２２Ｒ）６２ｇ及びエポキシ樹脂（シェル化学社製、商品名；エピコート８２８）４ｇをメタノール／メチルエチルケトン／トルエン（重量比＝２：２：１）の混合溶剤２５８ｇに溶解させ、接着剤組成物を調製した。
【０１６２】
次に、得られた接着剤組成物をプリント回路基板用銅箔に固形分としての厚さが３３μｍになるように塗布し、１４０℃で４分間乾燥して、接着剤層付き銅箔を得た。この接着剤層付き銅箔を温度２０℃、湿度７０％の条件に３日間放置した。その後、上記接着剤層付き銅箔とフェノール含浸紙とを１５０℃で３０分間、１２００Ｎ／ｃｍ^２の圧力で加圧成形し、銅箔積層板を積層した。
【０１６３】
（実施例１６〜１７、比較例１４〜１５）
変性ポリビニルアルコールの重合度、エチレン含有率、ケン化度、アルデヒドの種類、アセタール化度を表６に示したように変更したこと以外は実施例１５と同様にして接着剤組成物を作製し、これを用いて銅箔積層板を積層した。
【０１６４】
（実施例１８）
＜接着剤組成物の調整＞
実施例１２で作製した主鎖の構成単位としてエチレンをランダムに有する変性ポリビニルアセタール樹脂７ｇ、エポキシ樹脂（シェル化学社製、商品名；エピコート８２８）６０ｇ及びメラミン樹脂（三井化学社製、商品名；ユーバン２２Ｒ）５ｇをメタノール／メチルエチルケトン／トルエン（重量比＝２：２：１）の混合溶剤２５８ｇに溶解させ、接着剤組成物を調製した。
【０１６５】
次に、得られた接着剤組成物をプリント回路基板用銅箔に固形分としての厚さが３３μｍになるように塗布し、１４０℃で４分間乾燥して、接着剤層付き銅箔を得た。この接着剤層付き銅箔を温度２０℃、湿度７０％の条件に３日間放置した。
その後、上記接着剤層付き銅箔とガラスクロスをエポキシ樹脂で含浸したプリプレグとを１５０℃で３０分間、１２００Ｎ／ｃｍ^２の圧力で加圧成形し、銅箔積層板を積層した。
【０１６６】
（実施例１９〜２０、比較例１６〜１７）
変性ポリビニルアルコールの重合度、エチレン含有率、ケン化度、アルデヒドの種類、アセタール化度を表６に示したように変更したこと以外は実施例１５と同様にして接着剤組成物を作製し、これを用いて銅箔積層板を積層した。
【０１６７】
＜性能評価＞
実施例１２〜２０及び比較例１２〜１７で得られた銅箔積層板について、ＪＩＳＣ−６４８５に準拠して、ハンダ耐熱性及び引き剥がし強度を測定した。なお、試験温度は、ハンダ耐熱性については２６０℃、引き剥がし強度については１５０℃とした。結果を表６に示した。
【０１６８】
【表６】

【０１６９】
表６の結果より、ハンダ耐熱性、引き剥がし強度共に、実施例１２〜２０で得られた銅箔積層板は、比較例１２〜１７で得られた銅箔積層板よりも大幅に高かった。
【０１７０】
（実施例２１）
＜変性ポリビニルアセタール樹脂の製造＞
重合度３００、エチレン含有率５モル％、ケン化度９８モル％の主鎖の構成単位としてエチレンをランダムに有する変性ポリビニルアルコール１９３ｇを純水２９００ｇに加え、９０℃の温度で約２時間攪拌して溶解させた。この溶液を２８℃に冷却し、これに濃度３５重量％の塩酸２０ｇとｎ−ブチルアルデヒド１１５ｇとを添加し、液温を２０℃に下げてこの温度を保持してアセタール化反応を行い、反応生成物を析出させた。その後、液温を３０℃に５時間維持して反応を完了させ、常法により中和、水洗及び乾燥を行い、変性ポリビニルアセタール樹脂の白色粉末を得た。
【０１７１】
得られた変性ポリビニルアセタール樹脂をＤＭＳＯ−ｄ_６に溶解し、^１３Ｃ−ＮＭＲを用いてアセタール化度を測定したところ、アセタール化度は６８モル％であった。また、示差走査熱量計によりガラス転移温度を測定したところ、ガラス転移温度は１つのみ現れ、エタノール／トルエン＝１／１（重量比）の混合液、及び、メチルエチルケトンに完全に溶解したことから、変性ポリビニルアセタール樹脂が主鎖の構成単位としてエチレンをランダムに有するものであることが確認できた。
【０１７２】
＜インクの製造＞
上記変性ポリビニルアセタール樹脂４．４ｇとエタノール２５．６ｇとをガラス瓶に入れ２４時間攪拌し、次いで、顔料１０ｇとガラスビーズとを投入し、ペイントシェーカー（Ｒｅｄ Ｄｅｖｉｌ社製）にて９０分間振とうして顔料分散を行った。次いで、酢酸エチル８．５ｇを追加投入し、更に添加剤を少量投入して６０分間振とうを行ってインクを調製した。なお、ガラスビーズは、変性ポリビニルアセタール樹脂、エタノール及び酢酸エチルの合計重量に対して１．５倍量の重量投入した。
【０１７３】
（実施例２２〜２７、比較例１８〜２４）
変性ポリビニルアルコールの重合度、エチレン含有率、ケン化度、アルデヒドの種類、アセタール化度を表７に示したように変更したこと以外は実施例２１と同様にしてインクを調製した。実施例２２〜２７で得られた変性ポリビニルアセタール樹脂について示差走査熱量計によりガラス転移温度を測定したところ、含有される１種の変性ポリビニルアセタールに対応するガラス転移温度は１つのみ現れ、エタノール／トルエン＝１／１（重量比）の混合液、及び、メチルエチルケトンに完全に溶解したことから、変性ポリビニルアセタール樹脂が主鎖の構成単位としてエチレンをランダムに有するものであることが確認できた。
【０１７４】
＜性能評価＞
実施例２１〜２７及び比較例１８〜２４で得られたインクの経時粘度、基材への密着性、酸素透過度を以下の方法で評価し、結果を表７に示した。
【０１７５】
（インクの経時粘度測定）
メカニカルスペクトロメーター（レオメトリック社製、ＲＭＳ−８００）を用いてせん断速度１０００ｓ^−１、測定温度２５℃でのインクの粘度（ｍＰａ・ｓ）を測定した。ジオメトリーには二軸円筒型を使用した。測定はサンプルを二軸円筒型の容器にピペットにて必要量挿入後、プレシェアをかけて５分間放置した後に行った。続いて、各定常ずり速度をサンプルにかけた。定常ずり速度は、まず低速側（１ｓ^−１）から高速側（１０００ｓ^−１）にせん断速度をかけた後、更に高速側から低速側へせん断速度をかけた。流体の粘度挙動は高速せん断速度をかけた後のせん断速度１０００ｓ^−１時の粘度を粘度値（Ａ）とした。
６ヶ月後のインク状態を再現する加速促進試験として、４０℃で７２時間放置した後、上記方法と同様の方法で粘度を測定し、粘度値（Ｂ）とした。
上記粘度値（Ａ）と上記粘度値（Ｂ）からインクの粘度の変化率（粘度比）を算出した。
【０１７６】
（基材への接着性測定）
インクをバーコーターにて厚さ３０μｍのポリプロピレンフィルムの上に塗布し、厚さ３μｍのインク層を形成した後、温度２０℃、湿度９０％で３日間放置した。放置後、塗布面にセロハンテープを貼った後引き剥がし、フィルム上のインク残存量を目視にて観察し、以下の３段階で評価した。
○：セロハンテープ剥離後もインク層がフィルム上に完全に残っていた。
△：セロハンテープにインク層の一部が付着していた。
×：セロハンテープにインク層の大部分が付着していた。
【０１７７】
（酸素透過度測定）
インクをＰＥＴフィルムに塗布し、５０℃で６時間乾燥後、５０μｍの膜厚を持つインクフィルムを得た。次に室温において、このインクフィルムの減圧乾燥処理を６日間実施し測定に供した。測定には、差圧式ガス透過率測定システムを用い、試験ガスに酸素ガスを用い、試験ガス圧力１５Ｎ／ｃｍ^２、試験温度２５℃、ガス透過面積１５．２ｃｍ^２で測定し、酸素透過係数を求めた。
【０１７８】
【表７】

【０１７９】
表７の結果より、実施例２１〜２７で得られたインクは、比較例１８〜２４で得られたインクに比べ、インクの経時粘度変化及び酸素透過係数について、大幅に低く、基材への接着性について、大幅に良好であった。
【０１８０】
（実施例２８）
＜変性ポリビニルアセタール樹脂の製造＞
重合度５００、エチレン含有率５モル％、ケン化度９８モル％の主鎖の構成単位としてエチレンをランダムに有する変性ポリビニルアルコール１９３ｇを蒸留水２９００ｇに加え、９０℃の温度で約２時間攪拌して溶解させた。この溶液を２８℃に冷却し、これに濃度３５重量％の塩酸２０ｇとｎ−ブチルアルデヒド１２５ｇとを添加し、液温を２０℃に下げてこの温度を保持してアセタール化反応を行い、反応生成物を析出させた。その後、液温を３０℃に５時間維持して反応を完了させ、蒸留水にて洗浄し、水洗後の変性ポリビニルアセタール樹脂分散液に炭酸水素ナトリウムを添加して溶液をｐＨ８に調整した。次いで、溶液を６０℃で５時間保持した後冷却し、固形分に対し１００倍量の蒸留水で水洗した後、更に、溶液を５０℃で５時間保持した後１００倍量の蒸留水で水洗し、脱水した後乾燥した。
【０１８１】
得られた変性ポリビニルアセタール樹脂をＤＭＳＯ−ｄ_６に溶解し^１３Ｃ−ＮＭＲを用いてアセタール化度を測定したところ、アセタール化度は７５モル％であった。また、残存のアルデヒド量は１０ｐｐｍ、残存の水分量は２．０重量％であった。得られた変性ポリビニルアセタール樹脂について示差走査熱量計によりガラス転移温度を測定したところ、ガラス転移温度は１つのみ現れ、エタノール／トルエン＝１／１（重量比）の混合液、及び、メチルエチルケトンに完全に溶解したことから、変性ポリビニルアセタール樹脂が主鎖の構成単位としてエチレンをランダムに有するものであることが確認できた。なお、上記アルデヒド量の測定は、変性ポリビニルアセタール樹脂を加熱炉で熱抽出し、抽出物についてガスクロマトグラフィーを用いて測定した。上記水分量は、カールフィッシャー水分計を用いて測定した。
【０１８２】
＜熱現像性感光材料フィルム用塗工溶液の調製＞
上記変性ポリビニルアセタール樹脂５．０ｇ、ベヘン酸銀５．０ｇ、メチルエチルケトン４０ｇを２４時間ボールミルで混合し、更に、Ｎ−ラウリル−１−ヒドロキシ−２−ナフトアミド０．２ｇを加え、再びボールミルで粉砕して塗工溶液を得た。
【０１８３】
＜熱現像性感光材料フィルムの作製＞
上記塗工溶液を、ポリエステル基材上に乾燥後の厚みが１０μｍとなるように塗布し乾燥した。この塗工面上に、Ｎ，Ｎ一ジメチル−ｐ−フェニレンジアミン・硫酸鉛０．５ｇ、ポリビニルピロリドン２ｇ、メタノール３０ｍｌからなる溶液を乾燥後の厚みが１μｍとなるように塗布して乾燥した。このように積層して熱現像性感光材料フィルムを作製した。
【０１８４】
（実施例２９〜３４、比較例２５〜２８）
変性ポリビニルアセタール樹脂の重合度、ケン化度、アルデヒドの種類、アセタール化度、残存水分量、残存アルデヒド量を表８に示したように変更したこと以外は、実施例２８と同様にして熱現像性感光材料フィルムを作製した。実施例２９〜３４で得られた変性ポリビニルアセタール樹脂について示差走査熱量計によりガラス転移温度を測定したところ、含有される１種の変性ポリビニルアセタールに対応するガラス転移温度は１つのみ現れ、エタノール／トルエン＝１／１（重量比）の混合液、及び、メチルエチルケトンに完全に溶解したことから、変性ポリビニルアセタール樹脂が主鎖の構成単位としてエチレンをランダムに有するものであることが確認できた。
【０１８５】
＜性能評価＞
実施例２８〜３４及び比較例２５〜２８で得られた熱現像性感光材料フィルムの性能評価を以下の方法で行った。結果を表８に示した。
【０１８６】
（生フィルムの保存性）
熱現像性感光材料フィルムを湿度９０％、温度２０℃で１ヶ月間保管した。その後、感光性フィルムに階調パターンフィルムを通して２５０ワットの高圧水銀灯で２０ｃｍの距離から０．３秒間露光後、１１０℃の熱板を用いて３秒間加熱してシアン色のパターン画像を得た。これを以下の３水準で評価した。
○：かぶりがなく鮮明度が良好であった。
△：ややかぶりが発生し鮮明度が劣っていた。
×：かぶりが多数発生し鮮明度が悪かった。
【０１８７】
（生フィルムのブロッキング性）
熱現像性感光材料フィルムをＡ４サイズに切り、１００枚重ねて、湿度９０％、温度４０℃で１ヶ月間保管した。このときのブロッキングのレベルを以下の３水準で評価した。
○：全くブロッキングしておらず、きれいに１枚１枚が剥離した。
△：フィルムの一部がブロッキングして、剥離し難い部分があった。
×：フィルムの大部分がブロッキングしており、剥離がかなり困難であった。
【０１８８】
（画像形成後のフィルムの保存性）
感光性フィルムに階調パターンフィルムを通して２５０ワットの高圧水銀灯で２０ｃｍの距離から０．３秒間露光後、１１０℃の熱板を用いて３秒間加熱してシアン色のパターン画像を得た。その後、湿度９０％、温度４０℃で１ヶ月間保管した。このときのフィルム表面の状態を以下の３水準で評価した。
○：保管前と変わらない画像を形成していた。
△：一部で保管前と異なり、白くなった部分があった。
×：かなりの部分で保管前と異なり、白くなった部分があった。
【０１８９】
【表８】

【０１９０】
表８の結果より、実施例２８〜３４で得られた熱現像性感光材料フィルムは、比較例２５〜２８で得られた熱現像性感光材料フィルムに比べ、生フィルムの保存性、生フィルムのブロッキング性及び画像形成後のフィルム保存性について優れていた。
【０１９１】
（実施例３５）
＜変性ポリビニルアセタール樹脂の製造＞
重合度８００、エチレン含有率５モル％、ケン化度９３モル％の主鎖の構成単位としてエチレンをランダムに有する変性ポリビニルアルコール１９３ｇを純水２９００ｇに加え、９０℃の温度で約２時間攪拌して溶解させた。この溶液を２８℃に冷却し、これに濃度３５重量％の塩酸２０ｇとｎ−ブチルアルデヒド１１５ｇとを添加し、液温を２０℃に下げてこの温度を維持してアセタール化反応を行い、反応生成物を析出させた。その後、液温を３０℃に５時間維持して反応を完了させ、常法により中和、水洗及び乾燥を行い、主鎖の構成単位としてエチレンをランダムに有する変性ポリビニルアセタール樹脂の白色粉末を得た。
【０１９２】
得られた変性ポリビニルアセタール樹脂をＤＭＳＯ−ｄ_６に溶解し、^１３Ｃ−ＮＭＲを用いてアセタール化度を測定したところ、アセタール化度は６８モル％であった。また、示差走査熱量計によりガラス転移温度を測定したところ、ガラス転移温度は１つのみ現れ、エタノール／トルエン＝１／１（重量比）の混合液、及び、メチルエチルケトンに完全に溶解したことから、変性ポリビニルアセタール樹脂が主鎖の構成単位としてエチレンをランダムに有するものであることが確認できた。
【０１９３】
＜セラミックスグリーンシート用スラリー組成物の製造＞
上記変性ポリビニルアセタール樹脂１０重量部を、トルエン３０重量部とエタノール１５重量部との混合溶剤に加え攪拌溶解した。この樹脂溶液に、可塑剤としてジブチルフタレート３重量部を加え攪拌溶解した。こうして得られた樹脂溶液に、セラミックス粉末として平均粒子経０．３μｍのチタン酸バリウム粉末１００重量部を加え、ボールミルで３６時間混合してチタン酸バリウム粉末を分散させたセラミックスグリーンシート用スラリー組成物を得た。
【０１９４】
＜セラミックスグリーンシートの製造＞
上記セラミックスグリーンシート用スラリー組成物を、離型処理したポリエステルフィルム上に約６μｍの厚さで塗布し、常温で３０分間風乾し、更に熱風乾燥機により６０〜８０℃で１５時間乾燥して有機溶剤を乾燥させ、厚さ３μｍの薄層のセラミックスグリーンシートを得た。
【０１９５】
（実施例３６〜４１）
ポリビニルアルコールの重合度、エチレン含有率、ケン化度、アルデヒドの種類、アセタール化度、セラミックス粉末の平均粒子径、及び、可塑剤を表９に示したように変更したこと以外は実施例３４と同様にして、主鎖の構成単位としてエチレンをランダムに有する変性ポリビニルアセタール樹脂の製造、スラリー組成物及びセラミックスグリーンシートを製造した。なお、実施例３９〜４１では、変性ポリビニルアセタール樹脂の製造において、変性ポリビニルアルコール／未変性ポリビニルアルコール＝１／１（重量比）の混合物を用いた。実施例３６〜４１で得られた変性ポリビニルアセタール樹脂について示差走査熱量計によりガラス転移温度を測定したところ、含有される１種の変性ポリビニルアセタールに対応するガラス転移温度は１つのみ現れ、エタノール／トルエン＝１／１（重量比）の混合液、及び、メチルエチルケトンに完全に溶解したことから、変性ポリビニルアセタール樹脂が主鎖の構成単位としてエチレンをランダムに有するものであることが確認できた。
【０１９６】
（比較例２９〜３５）
エチレンを単量体単位として含まないことの他は実施例３５〜４１で用いた変性ポリビニルアルコールと同じ構造を有する未変性ポリビニルアルコールを用いたこと以外は、対応する実施例３５〜４１と同様にして、同じアセタール化度を有するポリビニルアセタール樹脂を作製し、これを用いてスラリー組成物の製造及びセラミックスグリーンシートの製造を行った。
【０１９７】
＜性能評価＞
実施例３５〜４１及び比較例２９〜３５で得られたスラリー組成物の粘度、粘度安定性、及び、セラミックスグリーンシートの剥離性、接着性、伸度を以下の方法により評価し、結果を表９及び表１０に示した。実施例３５〜４１及び比較例２９〜３５で得られたセラミックスグリーンシートの吸湿性、焼結後の熱分解残渣の量を以下の方法により評価し、結果を表１１に示した。
【０１９８】
（スラリー組成物の粘度及び粘度の差）
実施例３５〜４１及び比較例２９〜３５で得られたスラリー組成物の粘度をブルックフィールドタイプの回転粘度計を使用して２０℃で測定し、初期粘度とした。
次に、実施例３５で得られたスラリー組成物の粘度と、実施例３５に対応する比較例２９で得られたスラリー組成物の粘度とを比較し、下記式（６）により粘度の差（の割合）を求めた。
【０１９９】
【数６】

【０２００】
式（６）中、Ｇは、変性ポリビニルアセタール樹脂から作製したスラリー組成物（実施例３５）の粘度を表し、Ｈは、未変性ポリビニルアセタール樹脂から作製したスラリー組成物（比較例２９）の粘度を表す。
同様にして、実施例３６〜４１で得られたスラリー組成物の粘度と、実施例３６〜４１にそれぞれ対応する比較例３０〜３５で得られたスラリー組成物の粘度とを比較して粘度の差を求めた。
【０２０１】
（スラリー粘度の経時安定性（粘度変化率））
上記初期粘度を測定したスラリー溶液を２０℃の恒温室に１ケ月間保管し、保管後の粘度を、ブルックフィールドタイプの回転粘度計を使用して２０℃で測定し、粘度変化率を下記式（７）により求めた。
【０２０２】
【数７】

【０２０３】
式（７）中、Ｉは、１ケ月後の粘度を表し、Ｊは、初期粘度を表す。
【０２０４】
（セラミックスグリーンシートの剥離性）
実施例３５〜４１及び比較例２９〜３５で得られたセラミックスグリーンシートを１０ｃｍ角に切断し、ＰＥＴフィルム上に１０枚重ね、７０℃、圧力１５００Ｎ／ｃｍ^２、１０分間の熱圧条件で積層したのち、セラミックスグリーンシートをＰＥＴフィルムから剥離した際の剥離状態を目視を主体とする官能試験によって以下の３段階で評価した。
○：ＰＥＴフィルムに付着したセラミックスグリーンシートがなく、かつ、セラミックスグリーンシートの切れやクラックが全くなかった。
△：ＰＥＴフィルムに付着したセラミックスグリーンシートが一部認められ、又は、セラミックスグリーンシートの切れ、クラックが一部認められた。
×：ＰＥＴフィルムに付着したセラミックスグリーンシートが多数認められ、又は、セラミックスグリーンシートの切れ、クラックが多数認められた。
【０２０５】
（セラミックスグリーンシートの接着性）
実施例３５〜４１及び比較例２９〜３５で得られたセラミックスグリーンシートを１０ｃｍ角に切断して２００枚重ね、７０℃、圧力１５００Ｎ／ｃｍ^２、１０分間の熱圧条件で積層したのち、セラミックスグリーンシートの層間の接着性を目視を主体とする官能試験によって以下の３段階で評価した。
○：全く層間剥離が認められず、強固に接着している。
△：層間剥離が一部認められた。
×：層間剥離がかなり多く認められた。
【０２０６】
（シート伸度（伸度の差））
実施例３５〜４１及び比較例２９〜３５で得られたセラミックスグリーンシートを、２０℃の環境下、引っ張り速度１０ｍｍ／ｍｉｎで引っ張り、オートグラフ（島津製作所社製）を使用して最大点の伸度を測定した。
次に、実施例３５で得られたセラミックスグリーンシートの最大点の伸度と、実施例３５に対応する比較例２９で得られたセラミックスグリーンシートの最大点の伸度とを比較し、下記式（８）により伸度の差（の割合）を求めた。
【０２０７】
【数８】

【０２０８】
式（８）中、Ｋは、変性ポリビニルアセタール樹脂から作製されたセラミックスグリーンシート（実施例３５）の最大点の伸度を表し、Ｌは、未変性ポリビニルアセタール樹脂から作製されたセラミックスグリーンシート（比較例２９）の最大点の伸度を表す。
【０２０９】
同様にして、実施例３６〜４１で得られたセラミックスグリーンシートの最大点の伸度と、実施例３６〜４１にそれぞれ対応する比較例３０〜３５で得られたセラミックスグリーンシートの最大点の伸度を比較した。
【０２１０】
【表９】

【０２１１】
【表１０】

【０２１２】
表９及び表１０の結果より、実施例３５〜４１で得られたスラリー組成物は、比較例２９〜３５で得られたセラミックスグリーンシートに比べ、スラリー粘度が大幅に低く、スラリー粘度の経時安定性についても非常に安定していた。
また、実施例３５〜４１で得られたセラミックスグリーンシートは、剥離性、接着性のいずれも良好であった。一方、比較例３１、３２、３４、３５で得られたセラミックスグリーンシートは、硬く剥離時にクラックが入り、シート層間のかなりの部分で剥離していることが確認された。
また、実施例３５〜４１で得られたセラミックスグリーンシートは、比較例２９〜３５で得られたセラミックスグリーンシートに比べ、よく伸びるセラミックスグリーンシートであり、柔軟性に優れていた。
【０２１３】
（グリーンシートの吸湿性）
実施例３５〜４１及び比較例２９〜３５で得られたセラミックスグリーンシートを１０ｃｍ角に切断して、湿度９０％、温度２０℃で５日間放置し、放置前後で重量を測定した。放置前後での重量変化から下記式（９）によりセラミックスグリーンシートの吸湿性を求めた。
【０２１４】
【数９】

【０２１５】
式（９）中、Ｍは、放置後のセラミックスグリーンシートの重量を表し、Ｎは、放置前のグリーンシートの重量を表す。
【０２１６】
（変性ポリビニルアセタール樹脂の熱分解残渣）
実施例３５〜４１及び比較例２９〜３５で得られた変性ポリビニルアセタール樹脂１０ｍｇを窒素雰囲気中で、昇温速度１０℃／分で、常温から７００℃まで加熱した後の分解残渣の量を求めた。
【０２１７】
（セラミックスグリーンシートの熱分解残渣）
実施例３５〜４１及び比較例２９〜３５で得られたセラミックスグリーンシートを１０ｃｍ角に切断して５００枚重ね、温度７０℃、圧力１５００Ｎ／ｃｍ^２、時間１０分間の熱圧条件で積層しセラミックスグリーンシートの積層体を得た。次に、このセラミックスグリーンシートを窒素雰囲気で、昇温速度３℃／分で４５０℃まで昇温して５時間恒温を保った後、更に昇温速度５℃／分で１３５０℃まで昇温して１０時間恒温を保ち、セラミックスを完全に焼結した。このセラミックスグリーンシートを常温まで冷却した後、シートを半分に割り、ちょうど２５０層付近のセラミックスグリーンシートの状態を電子額微鏡で観察し、以下の３段楷で評価した。
○：均一に焼結されており、セラミックスパウダー以外のものはなかった。
△：セラミックスグリーンシート内に黒色の点状のものが一部まれに確認された。
×：セラミックスグリーンシート内に黒色の点状のものがかなり多く確認された。
【０２１８】
【表１１】

【０２１９】
表１１の結果より、実施例３５〜４１で得られたセラミックスグリーンシートは、比較例２９〜３５で得られたセラミックスグリーンシートに比べ、吸湿性が大幅に低く、含有される変性ポリビニルアセタール樹脂の熱分解残渣が大幅に少なく、かつ、セラミックスグリーンシート自体の熱分解残渣も非常に良好であり、熱分解残渣に起因する黒色のカーボンは確認されなかった。
【０２２０】
【発明の効果】
本発明によれば、柔軟性、高湿度下における樹脂基材への接着性、耐熱性、熱分解性、耐湿性、強靱性に優れ、酸素透過度が低く、適度の接着性を有し、溶液にしたときに低粘度で、粘度の経時安定性に優れた変性ポリビニルアセタール樹脂、及び、それを用いた接着剤組成物、インク、塗料組成物、熱現像性感光材料、セラミックスグリーンシート用スラリー組成物、及び、セラミックスグリーンシートを提供できる。[0001]
BACKGROUND OF THE INVENTION
The present invention is excellent in flexibility, adhesion to a resin substrate under high humidity, heat resistance, thermal decomposition, moisture resistance, toughness, low oxygen permeability, moderate adhesion, Modified polyvinyl acetal resin having low viscosity and excellent viscosity stability over time, and adhesive composition, ink, coating composition, heat-developable photosensitive material, and slurry composition for ceramic green sheet using the same And a ceramic green sheet.
[0002]
[Prior art]
Conventionally, polyvinyl acetal resins such as polyvinyl butyral resins are excellent in toughness, film-forming properties, dispersibility of inorganic and organic powders such as pigments, adhesion to coated surfaces, etc. It is used in various applications such as paints, baking enamels, wash primers, lacquers, dispersants, adhesives, ceramic green sheets, heat-developable photosensitive materials, aqueous ink-receiving layers, and other binders.
In this way, the greatest reason why polyvinyl acetal resin is used in various applications is because the polyvinyl acetal resin has a toughness due to its hydrogen bond because of the presence of hydroxyl groups in the polyvinyl acetal resin. The flexibility is somewhat poor.
[0003]
On the other hand, for example, Patent Document 1 discloses a technique for achieving internal plasticization of a polyvinyl acetal resin by introducing a unit having a long-chain glycol structure into the side chain of the polyvinyl acetal resin. However, although the flexibility of the polyvinyl acetal resin is improved by introducing a long chain, the solution viscosity when dissolved in a solvent increases, the storage stability in the solution is poor, and the viscosity increases with time. There was a problem.
[0004]
In particular, in recent years, from the viewpoint of environmental protection, the frequency of using a polyvinyl acetal resin excellent in solubility in alcohol-based single solvents such as ethanol and propanol without using aromatic solvents such as toluene and xylene. Is increasing. From the viewpoint of environmental protection, as seen in the VOC regulations for automobiles, there are three major flows: high solidification, water purification, and powdering. In particular, high-solidification requires less capital investment than the other two, only uses less solvent and increases the solids concentration, and can be inferred and guaranteed from the conventional product. It has been broken. As a method for realizing high solidification using a polyvinyl acetal resin, it is conceivable to increase the solid content concentration, that is, the binder content. However, when the solid content concentration is increased, the viscosity of the solution increases and the aging of the solution increases. There is a problem that the viscosity stability deteriorates.
[0005]
As a method for reducing the solution viscosity with respect to these problems, for example, a method by lowering the degree of polymerization or modifying the molecular structure can be mentioned. Patent Document 2 discloses a saponification degree of 70 to 96 mol%. A printing ink and a paint containing a polyvinyl butyral resin made from polyvinyl alcohol having a raw material are disclosed. However, in the solution containing this polyvinyl butyral resin, the viscosity is low, but the viscosity stability over time, the flexibility when made into a film is not sufficient, and by suppressing the amount of remaining acetyl groups, Although there is a description that low viscosity and high solidity can be realized, there was no description about other properties such as adhesion to a substrate and moisture resistance.
[0006]
One application of the polyvinyl acetal resin is a binder for ink or paint.
When the polyvinyl acetal resin is used as a binder for inks or paints, it is very often used as a printing ink for packaging materials, particularly high-design food packaging materials. Such ink for food packaging materials requires high designability but is highly versatile. For example, it is more solvent-based than a printing method using special techniques such as ultraviolet (UV) curing, which has recently attracted attention. The method of coating and drying is still mainstream. Moreover, since the package printed using the printing ink may directly touch the mouth, not only the amount of solvent / resin used but also the type is regulated. Among them, the polyvinyl acetal resin is used because it itself has little influence on environmental problems and is excellent in solubility in ethanol.
However, polyvinyl acetal resin is slightly inferior in adhesion to a substrate, particularly a resin film, and in particular, when the storage place is changed from a refrigerator to a room temperature environment, the ink itself absorbs moisture due to condensation, resulting in a base. There was a problem such as separation of the material and ink.
[0007]
Moreover, the guarantee period of a foodstuff becomes short, so that the oxygen permeability of the base film is high. This is because oxygen in the air permeates the base film and oxidizes and degrades the food inside the base film. On the other hand, for example, use a film with low oxygen permeability such as vinylidene chloride and eval. However, since these films are very expensive, olefin-based inexpensive films with high oxygen permeability such as polypropylene and polyethylene are mainly used. Polyvinyl acetal resins used as inks However, since it is easy to permeate oxygen, nitrogen, carbon dioxide, water vapor, etc., there is a problem that the oxygen permeability of the base film is increased and the guarantee period of the food is shortened.
[0008]
Moreover, an adhesive agent is mentioned as one of the uses of polyvinyl acetal resin.
Conventionally, an adhesive mainly composed of a polyvinyl acetal resin and a thermosetting resin such as a phenol resin, an epoxy resin, or a melamine resin has been widely used as an adhesive for printed circuit boards.
A printed circuit board is usually composed of a laminate composed of copper foil, phenol-impregnated paper, and an adhesive that bonds them, and the desired surface is obtained by etching the copper on the surface of the copper-clad laminate. A printed circuit board on which a printed circuit is formed can be obtained. In recent years, with the reduction in weight and size of various electronic and electrical devices, the size of printed circuit boards and the density of printed circuits have been increased. As a result, the immersion time in the solder bath when components are mounted on the printed circuit board is long. For this reason, adhesives that constitute printed circuit boards are required to have superior heat resistance compared to conventional adhesives, and in particular, improved adhesion strength of copper foil at high temperatures, that is, peeling strength of copper foil Improvements in solder resistance and solder heat resistance are strongly desired.
[0009]
In contrast, in Patent Document 3, polyvinyl acetal resin is mixed and acetalized to increase the heat resistance of the polyvinyl acetal resin itself; in Patent Document 4, maleic anhydride or maleic acid is introduced into the mixed acetal. In Patent Document 5, the heat resistance is improved by using about 85 to 100% by weight of the total acetalized portion as an acetalized portion with acetaldehyde having a high glass transition point. Etc. are disclosed. However, since the immersion time in the solder bath is significantly increased, the heat resistance of these polyvinyl acetal resins is still insufficient.
[0010]
Recently, as disclosed in Patent Document 6, as a multilayer printed circuit board, a copper foil with an adhesive is laminated on a prepreg in which a glass cloth or the like is impregnated with an epoxy resin, and the surface of the copper-clad laminate is obtained. After etching copper or forming a through hole, a copper foil with adhesive is further stacked on top of it, and etching is similarly performed to form a multilayer printed circuit board. The method is known. As an adhesive used at this time, as a thermosetting resin, an epoxy resin as a main component and a polyvinyl acetal resin added is known. However, improvement in heat resistance is also strongly desired for this adhesive. The heat resistance was still insufficient.
Furthermore, since the polyvinyl acetal resin has a hydroxyl group in the molecule, the adhesive layer absorbs moisture at high humidity such as in summer, resulting in a problem that solder heat resistance is deteriorated. .
[0011]
One of the uses of the polyvinyl acetal resin is a heat-developable photosensitive material.
The heat-developable photosensitive material mainly comprises a composition obtained by dispersing a silver salt of a fatty acid, an organic reducing agent, and optionally a small amount of photosensitive silver halide in a polymer binder, on a support. It will be.
Silver halide materials that have been widely used in the past are used in the field of image formation as a wider range and higher quality materials due to their excellent photographic properties, but development and fixing are complicated and processing steps are wet. Therefore, there is a problem that the treatment is complicated and a large amount of chemical waste liquid is discharged. On the other hand, photothermographic materials in which the development process is performed by heat treatment have been developed and put into practical use.
[0012]
For example, Patent Document 7 discloses a heat-developable photosensitive material comprising silver halide that is in catalytic contact with an organic silver salt, a reducing agent, and organic silver ions. Thermal development by coating a film forming binder such as polyvinyl butyral, polymethyl methacrylate, cellulose acetate, polyvinyl acetate, cellulose acetate propionate, cellulose acetate butyrate on a support such as metal foil or glass plate A photosensitive material is disclosed.
[0013]
As the film-forming binder, polyvinyl acetal resin is optimal. However, depending on the hygroscopicity of the polyvinyl acetal resin and the amount of water remaining, fogging, poor gradation, and insufficient sensitivity occur in the image characteristics after coating. In some cases, a change with time may occur during storage of the raw film and the film after image formation. Furthermore, general polyvinyl acetal resins have various compositions, and because they contain a small amount of impurities in the production process, the effect of these impurities causes the prepared binder solution to become photosensitized and colored, In some cases, the image characteristics after coating may cause fogging, poor gradation, insufficient sensitivity, or poor film preservability.
[0014]
In contrast, silver salts, reducing agents, additives, etc. have been improved. For example, Patent Document 8 discloses a technique in which a polyvinyl butyral resin is used as a binder and a silver salt of a thione compound is used without including an independent stabilizer and a stabilizer precursor component. However, a technique that solves the problem by specifying the composition of the binder is not disclosed.
[0015]
Further, among the heat-developable light-sensitive materials, the heat-developable silver salt film has slightly higher image characteristics, particularly image density and image / gradation part sharpness, compared to the conventional X-ray light-sensitive film using wet-type gelatin. However, in order to do so, it is necessary to strictly control the growth of silver nuclei during heating.
[0016]
Moreover, a multilayer ceramic capacitor is mentioned as one of the uses of polyvinyl acetal resin.
When manufacturing a multilayer ceramic capacitor, it is generally manufactured through the following steps. First, a binder resin and a plasticizer are added to a dispersion obtained by dispersing ceramic powder in an organic solvent, and the mixture is uniformly mixed and defoamed by a mixing device such as a ball mill to prepare a slurry composition. Next, this slurry composition is applied onto a peelable support using a doctor blade, a three-roll reverse coater or the like, heated and dried, and then peeled from the support to obtain a green sheet. On the obtained green sheet, a plurality of sheets obtained by applying a conductive paste serving as an internal electrode by screen printing or the like are stacked and thermocompression bonded to obtain a laminate. A multilayer ceramic capacitor can be obtained by sintering the external electrode on the end face of the ceramic sintered body obtained by cutting it into a predetermined shape and firing it.
[0017]
For such a green sheet, polyvinyl acetal resin such as polyvinyl butyral resin is used in order to improve handling properties. For example, it is disclosed in Patent Document 9, Patent Document 10, Patent Document 11, Patent Document 12, and the like. Has been.
[0018]
In recent years, with the miniaturization of electronic devices, multilayer ceramic capacitors are required to have a small size and a large capacity. As a measure for this, an attempt has been made to stack 500 or more thin green sheets (for example, 3 μm or less) obtained by using ceramic powder having a finer particle diameter (for example, 0.3 μm or less) than the conventional one. Yes.
[0019]
However, if the particle size of the ceramic powder is reduced, the surface area increases, so it is necessary to increase the amount of binder added. Therefore, not only the viscosity of the slurry is high and handling becomes difficult, but also the ceramic powder tends to agglomerate. There is a problem that the viscosity increases.
[0020]
In addition, in order to stack such thin green sheets to 500 layers or more, the adhesiveness at the time of thermocompression bonding, the peelability from the support and the strength of the green sheets are very important. For example, in order to improve the thermocompression bonding property at the time of lamination, it is effective to use a polyvinyl acetal resin having a high degree of acetalization and a small amount of hydroxyl groups or a low degree of polymerization, but the green sheet peels off from the support. In some cases, the green sheet may become difficult or the green sheet may be soft and may not have sufficient strength to withstand peeling in the peeling process. As a result, the green sheet may be torn or abnormally stretched. In order to improve the peelability of the green sheet from the support and the strength of the green sheet, it is effective to use a polyvinyl acetal resin having a low degree of acetalization and a large amount of hydroxyl groups or a high degree of polymerization. The adhesiveness at the time of thermocompression bonding is low, and the green sheet peels off from the laminated surface after pressure bonding, or when using a polyvinyl acetal resin with a high polymerization degree, the viscosity of the slurry becomes high and it becomes difficult to make a slurry. was there.
[0021]
On the other hand, it is conceivable to improve the thermocompression bonding property of the green sheet by increasing the amount of plasticizer added. However, if an excessive amount of plasticizer is added, the shrinkage rate during sintering may deteriorate, Since the plasticizer bleeds out over time when stored as a sheet, there is a problem in the storage stability of the green sheet.
[0022]
In addition, when the number of laminated layers increases, the decomposition of the binder in the binder removal step is difficult to proceed completely, and the decomposition product of the binder remains as a residue in the green sheet, and as a result, the electrical characteristics may be deteriorated. In addition, when using glass powder such as low-temperature sintered substrate (LTCC) and using copper wiring as an electrode, it is necessary that the binder is completely pyrolyzed at 500 ° C or less, and the pyrolysis is not complete May deteriorate the electrical characteristics. Here, the polyvinyl acetal resin has a problem that it has poor thermal decomposability and ash remains.
[0023]
Furthermore, multilayer ceramic capacitors that have been made thinner in green sheets are more susceptible to the external environment of the green sheets, especially moisture, and when a hygroscopic binder is used, There was a problem that strength and flexibility changed, and the rate of quality improvement decreased.
[0024]
As described above, the modified polyvinyl acetal resin can lower the viscosity when it is made into a solution in response to improvement in flexibility and high solidification for environmental protection, and can improve the stability with time of the viscosity. It was sought after. In addition, when used as a binder for inks and paints, it is required to lower the oxygen permeability in order to improve the adhesion to the resin substrate, particularly under high humidity, and to extend the warranty period of food. It was. In addition, when used as an adhesive for printed circuit boards, there has been a demand for improvement in heat resistance such as solder heat resistance and peel strength of metal foil under high temperature, and improvement in solder heat resistance under high humidity. . In addition, when used in heat-developable photosensitive materials, it improves moisture resistance and reduces moisture content, thereby improving raw film storage stability, film storage stability after image formation, and image characteristics. Was demanded. In addition, when used in a slurry composition for ceramic green sheets, improvement in thermal decomposability and moisture resistance is required. Therefore, it has been required to have a well-balanced adhesiveness that can achieve both the peelability and the releasability.
[0025]
[Patent Document 1]
JP-A-6-263521
[Patent Document 2]
Japanese Patent Laid-Open No. 11-349889
[Patent Document 3]
Japanese Patent Laid-Open No. 58-3802
[Patent Document 4]
JP 58-98307 A
[Patent Document 5]
JP-A-63-301208
[Patent Document 6]
JP-A-9-504970
[Patent Document 7]
Japanese Patent Publication No.43-4924
[Patent Document 8]
Japanese Patent Publication No.49-52626
[Patent Document 9]
Japanese Patent Laid-Open No. 3-197511
[Patent Document 10]
Japanese Patent Laid-Open No. 3-200805
[Patent Document 11]
JP-A-4-175261
[Patent Document 12]
Japanese Patent Laid-Open No. 4-178404
[0026]
[Problems to be solved by the invention]
In view of the present situation, the present invention is excellent in flexibility, adhesion to a resin base material under high humidity, heat resistance, thermal decomposition, moisture resistance, toughness, low oxygen permeability, and moderate adhesion. A modified polyvinyl acetal resin having a low viscosity when it is made into a solution and having excellent viscosity stability over time, and an adhesive composition, ink, coating composition, heat-developable photosensitive material, ceramic green using the same An object is to provide a slurry composition for a sheet and a ceramic green sheet.
[0027]
[Means for Solving the Problems]
The present invention 1 is a modified polyvinyl obtained by acetalizing a modified polyvinyl alcohol having ethylene as a constituent unit of the main chain at random, an ethylene content of 1 to 20 mol%, and a saponification degree of 80 mol% or more. An acetal resin, which is a modified polyvinyl acetal resin having ethylene as a main chain constituent unit randomly.
[0028]
The present invention 2 contains at least a modified polyvinyl alcohol having ethylene as a constituent unit of the main chain at random, and has an overall ethylene content of 1 to 20 mol% and an overall saponification degree of 80 mol%. A modified polyvinyl acetal resin obtained by acetalizing the polyvinyl alcohol mixture as described above, which is a modified polyvinyl acetal resin having ethylene as a constituent unit of the main chain at random.
[0029]
Invention 3 is an ink using the modified polyvinyl acetal resin of Invention 1 or Invention 2.
This invention 4 is a coating material using the modified polyvinyl acetal resin of this invention 1 or this invention 2.
The present invention 5 is an adhesive containing the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 and at least one thermosetting resin selected from the group consisting of a phenol resin, an epoxy resin and a melamine resin. .
The present invention 6 is a heat-developable photosensitive material using the modified polyvinyl acetal resin of the first or second invention.
This invention 7 is the slurry composition for ceramic green sheets containing modified vinyl acetal resin of this invention 1 or this invention 2, ceramic powder, a plasticizer, and an organic solvent.
The present invention is described in detail below.
[0030]
The modified polyvinyl acetal resin of the present invention 1 is obtained by acetalizing modified polyvinyl alcohol, and has random ethylene as a constituent unit of the main chain. By having ethylene as a constituent unit of the main chain at random, the viscosity when made into a solution can be reduced, and the effect of obtaining the stability over time of the viscosity, and flexibility, heat resistance, adhesiveness, moisture resistance, The effect of improving thermal decomposability, solvent solubility, etc. is obtained.
[0031]
In the present specification, having ethylene as a main chain constituent unit randomly means that not all ethylene units in the molecule are bonded together, but the ethylene units in the molecule are in the main chain. Means that it is divided into two or more.
[0032]
The modified polyvinyl acetal resin of the present invention 1 has random ethylene as a main chain constituent unit, for example, confirmed by the glass transition temperature measured by a differential scanning calorimeter or the solubility in an organic solvent. can do. In the measurement of the glass transition temperature, when ethylene is randomly included as a structural unit of the main chain, only one glass transition temperature appears. When ethylene units are present in blocks, the glass transition temperature Two temperatures appear. In the confirmation of the solubility in the organic solvent, when ethylene is randomly included as the structural unit of the main chain, the mixture is mixed with ethanol / toluene = 1/1 (weight ratio), an organic solvent such as methyl ethyl ketone. Dissolve completely. When the ethylene unit is present in blocks, the solubility in an organic solvent is inferior and undissolved matter is generated.
[0033]
The modified polyvinyl alcohol is not particularly limited as long as it has ethylene as a constituent unit of the main chain at random, for example, a saponified copolymer of vinyl ester and ethylene, vinyl ester, ethylene and ethylenic Examples include saponified copolymers obtained by copolymerization with unsaturated monomers, and terminal-modified polyvinyl alcohol. The modified polyvinyl acetal resin of the present invention 1 obtained by acetalization is obtained by improving the water solubility required for carrying out the acetalization reaction by having the modified polyvinyl alcohol have ethylene as a main chain constituent unit at random. It has ethylene as a structural unit of the chain at random.
[0034]
The randomness of the ethylene unit in the main chain of the modified polyvinyl alcohol can be controlled, for example, by adjusting the polymerization initiator, polymerization temperature, monomer addition method, polymerization time, etc. during copolymerization. it can. Moreover, it can confirm that the modified polyvinyl alcohol has ethylene as a structural unit of a main chain at random by the solubility to water, for example. When the modified polyvinyl alcohol has ethylene as a main chain constituent unit randomly, it is completely dissolved in water, and when the ethylene unit is present in a block, it is poor in solubility in water, Undissolved material is generated.
[0035]
The vinyl ester is not particularly limited, and examples thereof include vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, etc. Among them, vinyl acetate is economically preferable.
[0036]
The ethylenically unsaturated monomer is not particularly limited. For example, acrylic acid, methacrylic acid, phthalic acid, phthalic anhydride, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, acrylonitrile, methacrylonitrile, Acrylamide, methacrylamide, trimethyl- (3-acrylamido-3-dimethylpropyl) -ammonium chloride, acrylamido-2-methylpropanesulfonic acid and its sodium salt, ethyl vinyl ether, butyl vinyl ether, N-vinyl pyrrolidone, vinyl chloride, bromide Examples include vinyl, vinyl fluoride, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, sodium vinyl sulfonate, sodium allyl sulfonate, and the like.
[0037]
The terminal-modified polyvinyl alcohol is a copolymer obtained by copolymerizing a vinyl ester monomer such as vinyl acetate and ethylene in the presence of a thiol compound such as thiol acid such as thiol acetic acid and mercaptopropionic acid. It has become.
[0038]
The blending amount of the ethylenically unsaturated monomer blended in preparing the copolymer obtained by copolymerizing the vinyl ester, ethylene and the ethylenically unsaturated monomer is less than 2.0 mol%. Preferably there is. When many units derived from an ethylenically unsaturated monomer are contained, it becomes difficult to have sufficient water solubility, or the viscosity stability over time when the modified polyvinyl acetal resin of the present invention 1 is made into a solution is deteriorated. There are things to do. Especially, as said modified polyvinyl alcohol, what does not contain the unit derived from an ethylenically unsaturated monomer is preferable.
[0039]
The modified polyvinyl alcohol has an ethylene content of 1 to 20 mol%. When it is less than 1 mol%, the flexibility and heat resistance of the modified polyvinyl acetal resin of the present invention 1 are lowered, the effect of reducing the viscosity when made into a solution is small, the stability over time is deteriorated, the adhesiveness, The effect of improving moisture resistance and thermal decomposability cannot be sufficiently obtained. If it exceeds 20 mol%, the water-solubility of the modified polyvinyl alcohol is lowered, so that the acetalization reaction becomes difficult, the solvent solubility of the resulting modified polyvinyl acetal resin of the present invention 1 is deteriorated, or when the solution is made into a solution. The stability with time of viscosity may deteriorate. In the present specification, the ethylene content represents the ratio of the number of ethylene units to the total number of monomer units constituting the modified polyvinyl alcohol.
When the ethylene content of the modified polyvinyl alcohol is 1 to 20 mol%, the ethylene content of the modified polyvinyl acetal resin of the present invention 1 obtained by acetalization is also 1 to 20 mol%.
[0040]
The modified polyvinyl alcohol has a saponification degree of 80 mol% or more. If it is less than 80 mol%, the water-solubility of the modified polyvinyl alcohol is lowered, so that the acetalization reaction becomes difficult, and the acetalization reaction itself becomes difficult due to a decrease in the amount of hydroxyl groups.
[0041]
The acetalization can be performed by a known method by adding an aldehyde to the aqueous solution of the modified polyvinyl alcohol.
The aldehyde is not particularly limited. For example, formaldehyde (including paraformaldehyde), acetaldehyde (including paraacetaldehyde), propionaldehyde, butyraldehyde, amylaldehyde, hexylaldehyde, heptylaldehyde, 2-ethylhexylaldehyde, cyclohexylaldehyde, Examples include furfural, glyoxal, glutaraldehyde, benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, phenylacetaldehyde, β-phenylpropionaldehyde and the like. Of these, acetaldehyde and / or butyraldehyde are preferably used. These aldehydes may be used alone or in combination of two or more.
[0042]
The degree of acetalization of the modified polyvinyl acetal resin of the present invention 1 is either when the acetalization is performed with one aldehyde or when the acetalization is performed with a mixture of two or more aldehydes, It is preferable that it is 40-80 mol%. When it is less than 40 mol%, the modified polyvinyl acetal resin of the first invention becomes water-soluble and insoluble in an organic solvent. When it exceeds 80 mol%, the number of residual hydroxyl groups decreases and the toughness of the modified polyvinyl acetal resin of the present invention 1 may be impaired. In addition, you may select a more suitable range for the said acetalization degree according to the use of the modified polyvinyl acetal resin of this invention 1.
In the present specification, the degree of acetalization means that one acetal group is formed from two hydroxyl groups by acetalization, and therefore the degree of acetalization (mol%) when calculated by counting the acetal group as two hydroxyl groups. It is.
[0043]
Although the polymerization degree of the modified polyvinyl acetal resin of the first invention is not particularly limited, it is preferably 50 to 3500. Within this range, the modified polyvinyl acetal resin of the first invention and the modified polyvinyl alcohol can be produced with high productivity. More preferably, it is 200-3500. In addition, you may select a more suitable range for the said polymerization degree according to the use of the modified polyvinyl acetal resin of this invention 1.
[0044]
The water content of the modified polyvinyl acetal resin of the present invention 1 is preferably 2.5% by weight or less. If it exceeds 2.5% by weight, sufficient characteristics may not be exhibited when used in the photothermographic material of the invention 6 described later. Examples of the method for reducing the water content to 2.5% by weight or less include a method of removing the water content to a specified amount or less by drying after washing with water after acetalization or a mixed solution of water / alcohol. More preferably, it is 2.0 weight% or less.
[0045]
The aldehyde content of the modified polyvinyl acetal resin of the present invention 1 is preferably 100 ppm or less. If it exceeds 100 ppm, sufficient characteristics may not be exhibited when used in the photothermographic material of the invention 6 described later. Examples of the method of setting the aldehyde amount to 100 ppm or less include a method of purifying by a washing operation with water or a mixed solution of water / alcohol and the like to remove it to a specified amount or less. More preferably, it is 50 ppm or less, More preferably, it is 10 ppm or less.
[0046]
As a specific method for producing the modified polyvinyl acetal resin of the present invention 1, for example, modified polyvinyl alcohol is dissolved in a solvent and reacted with a predetermined amount of aldehyde so as to give a desired degree of acetalization in the presence of an acid catalyst. Then, the method of stopping an acetalization reaction with an alkali or a terminator, washing with water, and drying can be mentioned.
[0047]
The solvent is not particularly limited, and examples thereof include water, alcohol, water / alcohol mixed solvent, dimethyl sulfoxide (DMSO) and the like.
The acid catalyst is not particularly limited, and either an organic acid or an inorganic acid can be used. Examples thereof include acetic acid, paratoluenesulfonic acid, nitric acid, sulfuric acid, and hydrochloric acid.
It does not specifically limit as said alkali, For example, sodium hydroxide, potassium hydroxide, ammonia, sodium acetate, sodium carbonate, sodium hydrogencarbonate, potassium carbonate etc. are mentioned.
The terminator is not particularly limited, and examples thereof include alkylene oxides such as ethylene oxide and glycidyl ethers such as ethylene glycol diglycidyl ether.
[0048]
The modified polyvinyl acetal resin of the present invention 1 is obtained by acetalizing a modified polyvinyl alcohol having random ethylene content as a structural unit of the main chain and having a predetermined ethylene content and degree of saponification. Since the hydrogen bonding force is weakened, it is possible to form a coating film having a low viscosity when made into a solution, excellent stability over time, and excellent flexibility. Such a modified polyvinyl acetal resin of the present invention 1 can be effectively used in the fields of ceramics, inks, paints, adhesives, special coatings, various binders and the like.
[0049]
The modified polyvinyl acetal resin of the present invention 2 is obtained by acetalizing a polyvinyl alcohol mixture, and has random ethylene as a structural unit of the main chain. By having ethylene as a constituent unit of the main chain at random, the viscosity when made into a solution can be reduced, and the effect of obtaining the stability over time of the viscosity, and flexibility, heat resistance, adhesiveness, moisture resistance, The effect of improving thermal decomposability, solvent solubility, etc. is obtained. In addition, the modified polyvinyl acetal resin having ethylene randomly as the main chain constituent unit of the present invention 2 means a modified polyvinyl acetal resin containing a modified polyvinyl acetal randomly having ethylene as the main chain constituent unit. And it may contain unmodified polyvinyl acetal in part. The modified polyvinyl acetal in the modified polyvinyl acetal resin of the present invention 2 has ethylene as a main chain constituent unit at random, for example, a glass transition temperature measured by a differential scanning calorimeter of the modified polyvinyl acetal, This can be confirmed by the solubility of the modified polyvinyl acetal in an organic solvent. In the measurement of the glass transition temperature, when ethylene is randomly included as a structural unit of the main chain, only one glass transition temperature appears. When ethylene units are present in blocks, the glass transition temperature Two temperatures appear. In the confirmation of the solubility in the organic solvent, when ethylene is randomly included as the structural unit of the main chain, the mixture is mixed with ethanol / toluene = 1/1 (weight ratio), an organic solvent such as methyl ethyl ketone. Dissolve completely. When the ethylene unit is present in blocks, the solubility in an organic solvent is inferior and undissolved matter is generated.
[0050]
The said polyvinyl alcohol mixture consists of multiple types of polyvinyl alcohol, contains the modified polyvinyl alcohol which has ethylene at random as a structural unit of a principal chain, and may contain unmodified polyvinyl alcohol.
[0051]
The modified polyvinyl alcohol in the present invention 2 is not particularly limited as long as it has ethylene as a constituent unit of the main chain, for example, a saponified copolymer of vinyl ester and ethylene, vinyl ester and Examples include saponified copolymers obtained by copolymerizing ethylene and ethylenically unsaturated monomers, and terminal-modified polyvinyl alcohol. The modified polyvinyl acetal of the present invention 2 obtained by acetalization is obtained by improving the water-solubility necessary for carrying out the acetalization reaction because the modified polyvinyl alcohol in the present invention 2 has random ethylene as a main chain constituent unit. The resin has ethylene as a constituent unit of the main chain at random. In addition, about the randomness of the ethylene unit in the principal chain of the modified polyvinyl alcohol in the present invention 2, for example, by adjusting a polymerization initiator, a polymerization temperature, a monomer addition method, a polymerization time, etc. at the time of copolymerization. Can be controlled.
[0052]
As for the said polyvinyl alcohol mixture, the ethylene content rate as a whole is 1-20 mol%. When it is less than 1 mol%, the flexibility and heat resistance of the modified polyvinyl acetal resin of the present invention 2 are lowered, the effect of reducing the viscosity when made into a solution is small, the stability with time deteriorates, the adhesiveness, The effect of improving moisture resistance and thermal decomposability cannot be sufficiently obtained. If it exceeds 20 mol%, the water-solubility of the polyvinyl alcohol mixture decreases, so that the acetalization reaction becomes difficult, the solvent solubility of the resulting modified polyvinyl acetal resin of the present invention 2 becomes poor, The stability with time of viscosity may deteriorate.
[0053]
In addition, in this specification, ethylene content rate (mol%) as a whole of the said polyvinyl alcohol mixture multiplies the ethylene content rate of each polyvinyl alcohol which comprises the said polyvinyl alcohol mixture by weight ratio, and calculated | required the sum total. It is. Here, the ethylene content of the unmodified polyvinyl alcohol is 0 mol%. For example, about the polyvinyl alcohol mixture which consists of modified polyvinyl alcohol A and modified polyvinyl alcohol B, the ethylene content rate (mol%) as a whole is calculated | required from following formula (1).
[0054]
[Expression 1]

[0055]
In the formula (1), X represents the ethylene content as a whole of the polyvinyl alcohol mixture, and A ₁ Represents the weight of polyvinyl alcohol A, A ₂ Represents the ethylene content of polyvinyl alcohol A, B ₁ Represents the weight of polyvinyl alcohol B; ₂ Represents the ethylene content of polyvinyl alcohol B.
[0056]
Further, the ethylene content (mol%) as a whole of the modified polyvinyl acetal resin of the present invention 2 can be determined by the same method, but this is the same as the value of the polyvinyl alcohol mixture before the acetalization. Therefore, when the ethylene content is known for each of the polyvinyl alcohols constituting the modified polyvinyl alcohol mixture, this can be used. Moreover, the ethylene content as a whole of the modified polyvinyl acetal resin of the present invention 2 obtained by acetalization when the ethylene content as a whole of the polyvinyl alcohol mixture is 1 to 20 mol% is also 1 to 20 mol%. Become.
[0057]
The polyvinyl alcohol mixture has an overall saponification degree of 80 mol% or more. If it is less than 80 mol%, the water-solubility of the polyvinyl alcohol mixture is lowered, so that the acetalization reaction becomes difficult, and the acetalization reaction itself becomes difficult due to the decrease in the amount of hydroxyl groups.
[0058]
In the present specification, the saponification degree (mol%) of the polyvinyl alcohol mixture as a whole is obtained by multiplying the saponification degree of each polyvinyl alcohol constituting the polyvinyl alcohol mixture by a weight ratio and obtaining the sum. It is. For example, for a polyvinyl alcohol mixture composed of modified polyvinyl alcohol A and modified polyvinyl alcohol B, the overall saponification degree (mol%) is determined from the following formula (2).
[0059]
[Expression 2]

[0060]
In formula (2), Y represents the saponification degree as a whole of the polyvinyl alcohol mixture, and A ₁ Represents the weight of polyvinyl alcohol A, A ₃ Represents the degree of saponification of polyvinyl alcohol A, B ₁ Represents the weight of polyvinyl alcohol B; ₃ Represents the saponification degree of polyvinyl alcohol B.
[0061]
Further, the saponification degree (mol%) as a whole of the modified polyvinyl acetal resin of the present invention 2 can be determined by the same method, but this is the same as the value of the polyvinyl alcohol mixture before the acetalization. Therefore, when the degree of saponification is known for each of the polyvinyl alcohols constituting the modified polyvinyl alcohol mixture, this can be used. Moreover, when the saponification degree as a whole of a polyvinyl alcohol mixture is 80 mol% or more, the saponification degree as a whole of the modified polyvinyl acetal resin of the present invention 2 obtained by acetalization is also 80 mol% or more.
[0062]
The acetalization in the present invention 2 can be carried out by a known method by adding an aldehyde to the aqueous solution of the polyvinyl alcohol mixture.
The degree of acetalization of the modified polyvinyl acetal resin of the present invention 2 is either when the acetalization is performed with one aldehyde or when the acetalization is performed with a mixture of two or more aldehydes, It is preferable that it is 40-80 mol%. If it is less than 40 mol%, the modified polyvinyl acetal resin of the second invention becomes water-soluble and insoluble in an organic solvent. When it exceeds 80 mol%, the number of residual hydroxyl groups decreases, and the toughness of the modified polyvinyl acetal resin of the present invention 2 may be impaired. In addition, you may select a more suitable range for the said acetalization degree according to the use of the modified polyvinyl acetal resin of this invention 2.
[0063]
The degree of polymerization of the modified polyvinyl acetal resin of the present invention 2 is not particularly limited, but is preferably 50 to 3500. Within this range, the modified polyvinyl acetal resin and modified polyvinyl alcohol of the second invention can be produced with good productivity. More preferably, it is 200-3500. In addition, you may select a more suitable range for the said polymerization degree according to the use of the modified polyvinyl acetal resin of this invention 2. Moreover, in this specification, the polymerization degree of the modified polyvinyl acetal resin of the present invention 2 is obtained by multiplying the polymerization degree of each component constituting the modified polyvinyl acetal resin of the present invention 2 by a weight ratio and obtaining the sum. .
[0064]
The water content of the modified polyvinyl acetal resin of the present invention 2 is preferably 2.5% by weight or less. If it exceeds 2.5% by weight, sufficient characteristics may not be exhibited when used in the photothermographic material of the invention 6 described later. Examples of the method for reducing the water content to 2.5% by weight or less include a method of removing the water content to a specified amount or less by drying after washing with water after acetalization or a mixed solution of water / alcohol. More preferably, it is 2.0 weight% or less.
[0065]
The aldehyde content of the modified polyvinyl acetal resin of the present invention 2 is preferably 100 ppm or less. If it exceeds 100 ppm, sufficient characteristics may not be exhibited when used in the photothermographic material of the invention 6 described later. Examples of the method of setting the aldehyde amount to 100 ppm or less include a method of purifying by a washing operation with water or a mixed solution of water / alcohol and the like to remove it to a specified amount or less. More preferably, it is 50 ppm or less, More preferably, it is 10 ppm or less.
[0066]
As a specific method for producing the modified polyvinyl acetal resin of the present invention 2, for example, a polyvinyl alcohol mixture is dissolved in a solvent and reacted with a predetermined amount of aldehyde so as to give a desired degree of acetalization in the presence of an acid catalyst. Then, the method of stopping an acetalization reaction with an alkali or a terminator, washing with water, and drying can be mentioned.
[0067]
The modified polyvinyl acetal resin of the present invention 2 is obtained by acetalizing a polyvinyl alcohol mixture having a random ethylene content and a predetermined ethylene content and saponification degree as a structural unit of the main chain. Since the hydrogen bonding force is weakened, the viscosity when it is made into a solution is low, and it is possible to form a coating film having excellent temporal stability and excellent flexibility. Such a modified polyvinyl acetal resin of the present invention 2 can be effectively used in the fields of ceramics, inks, paints, adhesives, special coatings, various binders and the like.
[0068]
Invention 3 is an ink using the modified polyvinyl acetal resin of Invention 1 or Invention 2.
The degree of acetalization of the modified polyvinyl acetal resin of the present invention 1 or 2 when used in the ink of the present invention 3 is determined when the acetalization is performed with one aldehyde or when two or more acetalizations are mixed It is more preferable that it is 60-75 mol% even if it is any case when it is performed by. If it is less than 60 mol%, the hydrophilicity of the modified polyvinyl acetal resin of the present invention 1 or 2 may increase and the water resistance may not be sufficient. When it exceeds 75 mol%, the number of residual hydroxyl groups decreases, and the solubility of the modified polyvinyl acetal resin of Invention 1 or Invention 2 in an alcohol solvent may not be sufficient.
[0069]
The degree of polymerization of the modified polyvinyl acetal resin of the present invention 1 or 2 when used in the ink of the present invention 3 is not particularly limited, but is preferably 50 to 3500. If it is less than 50, production of polyvinyl alcohol as a raw material may be difficult. If it exceeds 3500, the solution viscosity of the ink of the present invention 3 becomes too high, the dispersibility is poor, and a uniform ink cannot be obtained. More preferably, it is 50-1000.
[0070]
The ink of the present invention 3 can be prepared by blending the polyvinyl acetal resin of the present invention 1 or the present invention 2, a pigment, an organic solvent and the like and mixing them by a conventional method.
[0071]
The blending amount of the modified polyvinyl acetal resin is preferably 5 to 25% by weight with respect to the total amount of the ink of the present invention 3. If it is less than 5% by weight, the film-forming property may be poor when an ink coating film is formed. If it exceeds 25% by weight, the solution viscosity becomes too high, and the dispersibility of the pigment may deteriorate. More preferably, it is 10 to 20% by weight.
[0072]
The pigment is not particularly limited, and examples thereof include inorganic pigments and organic pigments. The inorganic pigment is not particularly limited, and examples thereof include titanium oxide and carbon black. The organic pigment is not particularly limited, and examples thereof include diazo pigments and phthalocyanine pigments.
[0073]
The blending amount of the pigment is preferably 15 to 30% by weight as the concentrated ink and preferably 10 to 15% by weight as the diluted ink product with respect to the total amount of the ink of the present invention 3. If it is less than 10% by weight, the ink density after application becomes low and the target color may not be obtained. If it exceeds 30% by weight, the pigment may not be dispersed and may aggregate.
[0074]
The organic solvent is not particularly limited as long as it dissolves the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 and gives appropriate kneadability to the ink of the present invention 3. For example, acetone, methyl ethyl ketone, etc. Ketones; alcohols such as methanol, ethanol, isopropanol, n-propanol, and n-butanol; aromatic hydrocarbons such as toluene and xylene; and esters such as methyl acetate, ethyl acetate, and butyl acetate. However, alcohol solvents are preferred from the viewpoint of environmental protection. These organic solvents may be used independently and 2 or more types may be used together.
The blending amount of the organic solvent is preferably 60 to 85% by weight with respect to the total amount of the ink of the present invention 3.
[0075]
The ink of the present invention 3 may further contain an adhesion promoter, retarder, plasticizer, filler, wax, compatibilizer, surfactant, dispersant, tackifier, etc., if necessary. Good.
[0076]
The ink of the present invention 3 can be used without any problem even if it is stored for a long period of time because it uses the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 and has excellent viscosity stability over time even if it is made into a high solid. . In addition, the ink of the present invention 3 is excellent in adhesiveness and moisture resistance to a resin base material, and excellent in adhesiveness to a resin base material in a high humidity environment, so it is stored in a refrigerator such as ice cream or chocolate. It can be used effectively for printing food packaging materials, and has an excellent gas barrier property and low oxygen permeability, so that the warranty period of food can be extended.
[0077]
This invention 4 is a coating material using the modified polyvinyl acetal resin of this invention 1 or this invention 2.
The degree of acetalization of the modified polyvinyl acetal resin of the present invention 1 or 2 when used in the paint of the present invention 4 is an aldehyde in which acetalization is performed with one aldehyde or a mixture of two or more acetals It is more preferable that it is 60-75 mol% even if it is any case when it is performed by. If it is less than 60 mol%, the hydrophilicity of the modified polyvinyl acetal resin of the present invention 1 or 2 may increase and the water resistance may not be sufficient. When it exceeds 75 mol%, the number of residual hydroxyl groups decreases, and the solubility of the modified polyvinyl acetal resin of Invention 1 or Invention 2 in an alcohol solvent may not be sufficient.
[0078]
The degree of polymerization of the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 when used in the paint of the present invention 4 is not particularly limited, but is preferably 50-3500. If it is less than 50, production of polyvinyl alcohol as a raw material may be difficult. If it exceeds 3500, the solution viscosity of the paint of the present invention 4 becomes too high, the dispersibility is poor, and a uniform ink cannot be obtained. More preferably, it is 50-1000.
[0079]
The coating material of this invention 4 can be prepared by mix | blending the polyvinyl acetal resin of this invention 1 or this invention 2, a pigment, an organic solvent, etc., and mixing this by a conventional method.
[0080]
The blending amount of the modified polyvinyl acetal resin is preferably 5 to 25% by weight with respect to the total amount of the coating material of the present invention 4. If it is less than 5% by weight, the film-forming property may be poor when a paint film is formed. If it exceeds 25% by weight, the solution viscosity becomes too high, and the dispersibility of the pigment may deteriorate. More preferably, it is 10 to 20% by weight.
[0081]
The pigment in the present invention 4 is not particularly limited, and examples thereof include inorganic pigments and organic pigments, and the same pigments as those in the ink of the present invention 3 can be used.
The blending amount of the pigment is preferably 15 to 30% by weight as a concentrated paint and preferably 10 to 15% by weight as a diluted paint product with respect to the total amount of the paint of the present invention 4. If it is less than 10% by weight, the coating concentration after application becomes low and the target color may not be obtained. If it exceeds 30% by weight, the pigment may not be dispersed and may aggregate.
[0082]
The organic solvent in the paint of the present invention 4 is not particularly limited as long as it dissolves the modified polyvinyl acetal resin of the present invention 1 or 2 and gives the paint of the present invention 4 an appropriate kneadability. The same organic solvents as those in the ink of the present invention 3 can be used, and alcohol solvents are preferred from the viewpoint of environmental protection. These organic solvents may be used independently and 2 or more types may be used together.
The blending amount of the organic solvent is preferably 60 to 85% by weight with respect to the total amount of the coating material of the fourth invention.
[0083]
The paint of the present invention 4 may further contain an adhesion promoter, retarder, plasticizer, filler, wax, compatibilizer, surfactant, dispersant, tackifier, etc., if necessary. Good.
[0084]
The coating material of the present invention 4 can be used without any problem even if it is stored for a long period of time because it uses the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 and is excellent in viscosity stability over time even if it is made into a high solid. . Moreover, since the coating material of this invention 4 is excellent in the adhesiveness to a resin base material and moisture resistance, and is excellent in the adhesiveness to the resin base material in a high-humidity environment, it is stored by refrigeration, such as ice cream and chocolate. It can be used effectively for printing food packaging materials, and has an excellent gas barrier property and low oxygen permeability, so that the warranty period of food can be extended.
[0085]
The present invention 5 is an adhesive containing the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 and at least one thermosetting resin selected from the group consisting of a phenol resin, an epoxy resin and a melamine resin. .
The degree of acetalization of the modified polyvinyl acetal resin of the present invention when used for the adhesive of the present invention 5 was performed when the acetalization was performed with one aldehyde and with a mixture of two or more acetals In any case, it is more preferably 60 to 80 mol%. If it is less than 60 mol%, the hydrophilicity of the modified polyvinyl acetal resin of the present invention 1 or 2 may increase and the water resistance may not be sufficient. When it exceeds 80 mol%, the number of residual hydroxyl groups decreases, and the toughness of the modified polyvinyl acetal resin of the present invention 1 or 2 may be impaired, or the reactivity with the thermosetting resin may be reduced.
[0086]
The degree of polymerization of the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 when used in the adhesive of the present invention 5 is not particularly limited, but is more preferably 1000 to 3500. If it is less than 1000, the peel strength after bonding may decrease, and if it exceeds 3500, the viscosity of the adhesive solution becomes too high, resulting in poor coatability and obtaining a uniform adhesive composition. Can not. More preferably, it is 1500-3000.
[0087]
The blending ratio of the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 and the thermosetting resin in the adhesive of the present invention 5 is preferably 3:97 to 70:30 in weight ratio. If the blending ratio of the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 is less than 3, the adhesiveness to the copper foil may be lowered, and if it exceeds 70, the heat resistance may be deteriorated. Especially, when the main component of the said thermosetting resin is a phenol resin and / or a melamine resin, it is more preferable that it is 30: 70-70: 30 by weight ratio, and the main of the said thermosetting resin is When the component is an epoxy resin, the weight ratio is more preferably 3:97 to 30:70.
[0088]
The solvent used for preparing the adhesive of the present invention 5 is not particularly limited, and examples thereof include ketones such as acetone methyl ethyl ketone; alcohols such as methanol, ethanol and butanol; aromatic hydrocarbons such as toluene and xylene. Etc. are used as appropriate.
[0089]
The adhesive of the present invention 5 contains additives such as a thermosetting resin, a curing agent, an antioxidant, an antifoaming agent, and an antistatic agent other than the above, depending on the purpose such as improvement of heat resistance. Also good.
[0090]
The adhesive of the present invention 5 contains the modified polyvinyl acetal resin of the present invention 1 or the present invention 2, so that the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 is highly reactive with a thermosetting resin, Since it is excellent in hygroscopicity, it has excellent heat resistance and adhesive strength, and particularly excellent in heat resistant adhesive strength. If the adhesive of the present invention 5 is used, for example, as an adhesive for a laminated board of a printed circuit board, the heat resistance, particularly the solder heat resistance and the peel strength can be greatly improved. The foil has excellent solder heat resistance and peel strength even when left for a long time in a high humidity environment.
[0091]
The present invention 6 is a heat-developable photosensitive material using the modified polyvinyl acetal resin of the first or second invention.
The modified polyvinyl acetal resin of the present invention 1 or 2 when used in the photothermographic material of the present invention 6 is particularly preferably acetalized with acetaldehyde and / or butyraldehyde, The photothermographic material of the present invention 6 can easily balance the image characteristics.
[0092]
The degree of acetalization of the modified polyvinyl acetal resin of the present invention 1 or 2 when used in the heat-developable photosensitive material of the present invention 6 is a case where acetalization is performed with one aldehyde and two acetalizations are performed. Even if it is any case where it carries out with the aldehyde mixed above, it is more preferable that it is 65-80 mol%. If it is less than 65 mol%, the modified polyvinyl acetal resin of the present invention 1 or 2 will have a large amount of hydroxyl groups, making it difficult to balance the hydrophilicity, and the organic acid will produce a crystalline substance during film storage after image formation. In some cases, the surface of the coating film becomes whitish. If it exceeds 80 mol%, the number of residual hydroxyl groups will decrease, the toughness of the modified polyvinyl acetal resin of the present invention 1 or 2 will be impaired, and the coating film strength will decrease, or the dispersibility of silver halide will deteriorate. Image characteristics and the like may be deteriorated.
[0093]
The degree of polymerization of the modified polyvinyl acetal resin of Invention 1 or Invention 2 when used in the heat-developable photosensitive material of Invention 6 is not particularly limited, but is preferably 200 to 3000. More preferably, it is 200-1000 which is easy to balance the dispersibility, coating film strength, coating property, etc. of the silver salt used in the photothermographic material of the invention 6.
[0094]
When used in the photothermographic material of the invention 6, the amount of residual acetyl groups in the modified polyvinyl acetal resin of the invention 1 or the invention 2 is preferably 25 mol% or less. If it exceeds 25 mol%, the resulting photosensitive films may be blocked or the image may not be clear. More preferably, it is 15 mol% or less.
[0095]
When used in the photothermographic material of the invention 6, the water content of the modified polyvinyl acetal resin of the invention 1 or the invention 2 is preferably 2.5% by weight or less. If it exceeds 2.5% by weight, the pot life of the coating solution will be reduced, or a coating film sufficient to react with a crosslinking agent added to improve the film strength, for example, a compound containing an isocyanato group. Strength may not be obtained, or it may cause fogging when the amount of crosslinking agent added is increased in anticipation of reaction with water. Examples of the method for reducing the water content to 2.5% by weight or less include a method of removing the water content to a specified amount or less by drying after washing with water after acetalization or a mixed solution of water / alcohol. More preferably, it is 2.0 weight% or less.
[0096]
The aldehyde content of the modified polyvinyl acetal resin of the present invention 1 or 2 when used in the heat-developable photosensitive material of the present invention 6 is preferably 100 ppm or less. If it exceeds 100 ppm, the aldehyde is reduced by the reducing agent contained in the coating solution, the storage stability of the coating solution is reduced, and the raw storage stability of the film may be reduced, and this may cause fogging. Examples of the method of setting the aldehyde amount to 100 ppm or less include a method of purifying by a washing operation with water or a mixed solution of water / alcohol and the like to remove it to a specified amount or less. More preferably, it is 50 ppm or less, More preferably, it is 10 ppm or less.
[0097]
In the production of the modified polyvinyl acetal resin of Invention 1 or Invention 2 when used in the heat-developable photosensitive material of Invention 6, antioxidants such as hindered phenols, bisphenols, and phosphates are used. It is preferable not to use it. Usually, in the acetalization reaction between a modified polyvinyl alcohol and an aldehyde, an antioxidant is added to the reaction system or the resin system in order to prevent oxidation of the aldehyde, or to improve the oxidation resistance and heat resistance of the resulting modified polyvinyl acetal resin. However, if the above-mentioned antioxidant is used, it remains in the modified polyvinyl acetal resin of the present invention 1 or 2, resulting in a decrease in the pot life of the coating solution and a decrease in the raw storage stability of the raw film. , The fog and the sharpness of the image / gradation part may be impaired.
[0098]
The composition of the heat-developable photosensitive material of the present invention 6 is the same as that of the conventional heat-developable photosensitive material except that the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 is used. The modified polyvinyl acetal resin of the present invention 2 is blended with an organic silver salt, a reducing agent, and if necessary, a small amount of a photosensitive silver halide or silver halide forming component, a crosslinking agent, a sensitizer, etc. In the case of forming a color image, a color toning agent may be further blended. In the case of forming a color image, a color coupler, a leuco dye or the like may be blended.
[0099]
The blending amount of the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 is preferably 1:10 to 10: 1, more preferably 1: 5 to 5: 1, with respect to the organic silver salt in weight ratio. It is.
[0100]
The organic silver salt is a colorless or white silver salt that is relatively stable to light.
The organic silver salt is not particularly limited as long as it reacts with a reducing agent to produce silver when heated to 80 ° C. or higher in the presence of a photosensitive silver halide. For example, mercapto group, thione group Or the silver salt of the organic compound which has a carboxyl group; benzotriazole silver etc. are mentioned. Specifically, a silver salt of a compound having a mercapto group or a thione group, a silver salt of 3-mercapto-4-phenyl1,2,4-triazole, a silver salt of 2-mercapto-benzimidazole, 2-mercapto-5 Silver salt of aminothiazole, silver salt of 1-phenyl-5-mercaptotetrathiazole, silver salt of 2-mercaptopentazothiazole, silver salt of thioglycolic acid, silver salt of dithioacetic acid, etc. , Silver thioamide, silver thiopyridine, silver salt of mercaptooxadiazole, silver salt of mercaptotriazine, silver salt of aliphatic carboxylic acid; silver caprate, silver laurate, silver myristate, silver palmitate, silver stearate, Silver behenate, silver maleate, silver fumarate, silver tartrate, silver furoate, silver linoleate, silver oleate, hydroxystearin Silver, silver adipate, silver sebacate, silver succinate, silver acetate, silver butyrate, silver camphorate, etc., silver aromatic carboxylate, silver thiocarboxylate, silver aliphatic carboxylate with thioether group, tetrazaindene Silver salts, silver S-2-aminophenylthiosulfate, metal-containing amino alcohols, organic acid metal chelates and the like can be mentioned. Of these, a silver salt of an aliphatic carboxylic acid is preferable, and silver behenate is more preferable.
The particle diameter of the organic silver salt is preferably 0.01 to 10 μm, more preferably 0.1 to 5 μm.
[0101]
Photosensitive silver halide may be catalytically contacted with the organic silver salt.
The photosensitive silver halide is not particularly limited, and examples thereof include silver bromide, silver iodide, silver chloride, silver chlorobromide, silver iodobromide, and silver chloroiodide.
The method for bringing the photosensitive silver halide into catalytic contact with the organic silver salt is not particularly limited. For example, in a solution or dispersion of a previously prepared organic silver salt, or a film material containing the organic silver salt, Examples thereof include a method of forming a part of organic silver into silver halide by allowing a silver halide forming component to act.
The photosensitive silver halide forming component is not particularly limited as long as it acts on an organic silver salt to form silver halide, but it preferably contains iodine ions.
The blending amount of the photosensitive silver halide is preferably 0.0005 to 0.2 parts by weight, more preferably 0.01 to 0.2 parts by weight with respect to 100 parts by weight of the organic silver salt.
[0102]
The reducing agent is not particularly limited and is appropriately selected depending on the organic silver salt used together. For example, substituted phenols, bisphenols, naphthols, bisnaphthols, polyhydroxybenzenes, di- or polyhydroxynaphthalenes , Hydroquinone monoethers, ascorbic acid or derivatives thereof, reducing sugars, aromatic amino compounds, hydroxyamines, hydrazines, phenidones, hydroquinones, hindered phenols, etc. Some are degradable. Among these, a photodegradable reducing agent is preferable, and hindered phenols are particularly preferable.
[0103]
The amount of the reducing agent is preferably 0.0001 to 3.0 parts by weight, more preferably 0.01 to 1.0 parts by weight, based on 100 parts by weight of the organic silver salt.
The reducing agent may be used in combination with a compound that promotes photolysis, or may be used in combination with a coating agent for inhibiting the reaction between silver halide and the reducing agent.
[0104]
As a method for producing the heat-developable photosensitive material of the present invention 6, for example, the modified polyvinyl acetal resin, the organic silver salt, the reducing agent and the solvent of the present invention 1 or the present invention 2 are dispersed with a ball mill and then, if necessary. Further, add silver halide or silver halide forming components and various additives, disperse with a ball mill, apply the resulting dispersion on a support so that the organic silver salt is in a prescribed amount, and evaporate the solvent. And the like. In addition, the organic silver salt and the reducing agent may be combined into the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 and formed into a single layer on the support, The organic silver salt and the reducing agent may be separately added to the modified polyvinyl acetal resin of the present invention 1 or 2, and these may be formed in two layers on the support.
[0105]
As said solvent, the thing which can melt | dissolve the modified polyvinyl acetal resin of this invention 1 or this invention 2, and hardly contains a water | moisture content is used suitably. Of these, ketones and esters are preferable, and diethyl ketone, methyl ethyl ketone, methyl-iso-butyl ketone, methyl acetate, ethyl acetate, propyl acetate, and the like are more preferable.
[0106]
Examples of the support include resin films such as polyethylene terephthalate, polycarbonate, polyethylene, polypropylene, polyvinyl acetal, cellulose ester, cellulose diacetate, cellulose triacetate, nitrocellulose, polyethylene naphthalate, vinyl chloride, and chlorinated polypropylene; glass; Paper: A metal plate such as an aluminum plate is used.
[0107]
The amount of silver coated on the support is 1 m of support. ² It is preferably 0.1 to 5.0 g per unit. If it is less than 0.1 g, the image density may be low, and if it exceeds 5.0 g, no improvement in the image density is observed. More preferably, it is 0.3-3.0 g. The application may be either double-sided or single-sided.
[0108]
The photothermographic material of the present invention 6 has no blocking problem even when stored for a long period of time, can reduce the storage stability of the raw film due to moisture absorption, can prevent fogging, and maintain a hydrophilic balance. Therefore, the film has excellent storage properties after image formation, and exhibits excellent image characteristics.
[0109]
This invention 7 is the slurry composition for ceramic green sheets containing modified vinyl acetal resin of this invention 1 or this invention 2, ceramic powder, a plasticizer, and an organic solvent.
The degree of acetalization of the modified polyvinyl acetal resin of Invention 1 or Invention 2 when used in the slurry composition for ceramic green sheets of Invention 7 is determined when the acetalization is carried out with one kind of aldehyde. Even if it is any case where it carries out with the aldehyde which mixed 2 or more types, it is more preferable that it is 40-79 mol%. If it is less than 40 mol%, the modified polyvinyl acetal resin of the present invention 1 or 2 will be water-soluble and insoluble in organic solvents. When it exceeds 79 mol%, the number of residual hydroxyl groups decreases, the toughness of the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 is impaired, and the strength of the green sheet may be lowered.
[0110]
The degree of polymerization of the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 when used in the slurry composition for a ceramic green sheet of the present invention 7 is not particularly limited, but is preferably 300 to 2400. If it is less than 300, the strength when molded into a ceramic green sheet is low, and the ceramic green sheet is likely to break or crack when peeled off from the support, and if it exceeds 2400, the solution viscosity of the slurry is high. Since it becomes too high, dispersibility is bad and a uniform slurry cannot be obtained.
[0111]
The blending amount of the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 is preferably 3 to 15% by weight with respect to the total amount of the slurry composition for a ceramic green sheet of the present invention 7. When the amount is less than 3% by weight, the amount of the modified polyvinyl acetal resin of the present invention 1 or 2 dispersed in the entire ceramic powder becomes insufficient, and the resulting ceramic green sheet has insufficient flexibility, and after sintering. Cracks and the like may occur. When it exceeds 15% by weight, the viscosity of the slurry composition for ceramic green sheets of the present invention 7 becomes too high and the dispersibility is lowered, or the shrinkage ratio of the sheet becomes large when the obtained ceramic green sheet is fired. Or
[0112]
It does not specifically limit as said ceramic powder, The ceramic powder conventionally used for manufacturing a ceramic green sheet is mentioned. Examples of such ceramic powder include alumina, zirconia, aluminum silicate, titanium oxide, zinc oxide, barium titanate, magnesia, sialon, spinel mullite, crystallized glass, carbonized silicic acid, silicic acid nitride, aluminum nitride, etc. The powder which consists of is mentioned. These ceramic powders may be used alone or in combination of two or more.
[0113]
These ceramic powders include MgO-SiO ₂ -CaO, B ₂ O ₃ -SiO ₂ System, PbO-B ₂ O ₃ -SiO ₂ System, CaO-SiO ₂ -MgO-B ₂ O ₃ System or PbO-SiO ₂ -B ₂ O ₃ You may add glass frit, such as -CaO type | system | group.
[0114]
The ceramic powder preferably has a fine particle diameter, and in order to obtain a thin ceramic green sheet, it is particularly preferable to use a ceramic powder having a fine particle diameter. For example, in order to obtain a ceramic green sheet of 3 μm or less, the particle size of the ceramic powder is preferably 0.3 μm or less.
[0115]
The blending amount of the ceramic powder is preferably 30 to 80% by weight based on the total amount of the slurry composition for a ceramic green sheet of the present invention 7. If it is less than 30% by weight, the viscosity of the ceramic green sheet slurry composition of the present invention 7 may become too low, and handling properties may be deteriorated when the ceramic green sheet is formed. If it exceeds 80% by weight, the viscosity of the ceramic green sheet slurry composition of the present invention 7 may become too high and the kneadability may be lowered.
[0116]
The plasticizer is not particularly limited, and any plasticizer can be used as long as it has excellent compatibility with the modified polyvinyl acetal resin of the first or second invention. For example, phthalate esters such as dibutyl phthalate, dioctyl phthalate, diisodecyl phthalate, butyl benzyl phthalate; phosphate esters such as tricresyl phosphate, tributyl phosphate, triethyl phosphate; methyl acetyl ricinoleate, sebacic acid Examples thereof include fatty acid ester systems such as dibutyl and dioctyl adipate; glycol derivatives such as butylphthalyl glycolate and triethylene glycol-2-ethylbutyrate. These plasticizers may be used independently and 2 or more types may be used together.
[0117]
The blending amount of the plasticizer is preferably 0.1 to 10% by weight based on the total amount of the slurry composition for a ceramic green sheet of the present invention 7. If it is less than 0.1% by weight, the flexibility of the ceramic green sheet due to the blending of the plasticizer cannot be sufficiently obtained. If it exceeds 10% by weight, the ceramic green sheet becomes too soft, and the handling property when the ceramic green sheet is formed may deteriorate.
[0118]
The organic solvent is not particularly limited, and examples thereof include ketones such as acetone and methyl ethyl ketone; alcohols such as methanol, ethanol, isopropanol, n-propanol, and n-butanol; aromatic hydrocarbons such as toluene and xylene. Can be mentioned. These organic solvents may be used independently and 2 or more types may be used together.
[0119]
The amount of the organic solvent is preferably 20 to 80% by weight based on the total amount of the slurry composition for a ceramic green sheet of the present invention 7. Within this range, the modified polyvinyl acetal resin of the present invention 1 or the present invention 2 can be dissolved, and an appropriate kneadability can be imparted to the slurry composition for a ceramic green sheet of the present invention 7.
[0120]
The slurry composition for a ceramic green sheet of the present invention 7 includes a lubricant, a dispersant, a deflocculant, a wetting agent, an antistatic agent, an antibacterial agent within the range where the object of the present invention 7 can be achieved. You may contain a foaming agent etc.
[0121]
The slurry composition for a ceramic green sheet of the present invention 7 is prepared by blending the modified polyvinyl acetal resin of the present invention 1 or the present invention 2, ceramic powder, a plasticizer and an organic solvent and mixing them by a conventional method. Can do.
[0122]
A ceramic green sheet can be obtained by shaping the slurry composition for a ceramic green sheet of the present invention 7 into a sheet shape and drying it. For example, after degassing the ceramic green sheet slurry composition of the present invention 7 as necessary, it is applied onto a support such as a peelable polyester film or stainless steel plate, and the organic solvent is removed by heating and drying. Remove and then peel from the support. A ceramic green sheet using such a slurry composition for a ceramic green sheet of the present invention 7 is also one aspect of the present invention.
[0123]
A multilayer ceramic capacitor can be obtained by using the ceramic green sheet of the present invention. The multilayer ceramic capacitor is formed by stacking a plurality of conductive ceramic pastes applied to the internal electrode by screen printing or the like on the ceramic green sheet of the present invention, and thermocompression-bonding to produce a multilayer body. And after cutting into dimensions, the polyvinyl acetal resin of the present invention 1 or 2 used as a binder resin by heating to a high temperature of, for example, about 600 ° C. is almost completely decomposed, and further, for example, to a high temperature of, for example, about 1350 ° C. It is obtained by sintering the ceramic powder by heating, and then sintering the external electrode on the end face of the obtained ceramic sintered body.
[0124]
The slurry composition for a ceramic green sheet of the present invention 7 contains the polyvinyl acetal resin of the present invention 1 or 2 as a binder resin, and the hydrogen bond strength of the modified polyvinyl acetal resin is sterically hindered. Therefore, compared with the case where only the unmodified polyvinyl acetal resin is used as the binder resin, the viscosity is stable with time and the viscosity is excellent. As a result, the amount of solvent used can be reduced to form a high solid, and the slurry can be stored for a long time.
[0125]
In the ceramic green sheet of the present invention, since the slurry composition for a ceramic green sheet of the present invention 7 does not need to contain an excessive amount of plasticizer, the sheet strength, particularly the elongation, is greatly improved and is easily peeled off from the support. And the adhesiveness balance at the time of lamination | stacking excellent in the adhesiveness at the time of pressure bonding is a favorable thing. Further, since the ceramic green sheet of the present invention has low hygroscopicity, it can be stored for a long time in the state of the ceramic green sheet, and is hardly affected by humidity when processing such as punching. Therefore, even a thin ceramic green sheet having a thickness of 3 μm or less can be molded without being affected by humidity, and can be laminated without damaging the ceramic green sheet. Furthermore, the ceramic green sheet of the present invention is a thin ceramic green sheet having a thickness of 3 μm or less because the modified polyvinyl acetal resin of the present invention 1 or 2 is excellent in thermal decomposability and has very few pyrolysis residues. Even when a laminate in which 500 or more layers are stacked is sintered, there is no thermal decomposition residue of the binder in the sintered ceramic green sheet, and a laminate excellent in electrical characteristics can be obtained. Therefore, it is possible to cope with the downsizing of electronic parts such as multilayer ceramic capacitors, and LTCC (low temperature sintering) that requires a low binder removal property such as using glass powder or using copper as an electrode. It can also be used for (bonded substrates). Further, the ceramic green sheet of the present invention has dramatically improved compatibility with a plasticizer because the modified polyvinyl acetal resin of the present invention 1 or 2 contains an ethylene unit as a monomer unit. Therefore, the bleed-out of the plasticizer can be suppressed, the ceramic green sheet can be stored for a long period of time, and since the shrinkage rate during sintering is small, the dimensional stability and the like can be improved and the size of the parts can be reduced.
[0126]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
[0127]
(Example 1)
<Manufacture of modified polyvinyl acetal resin>
193 g of modified polyvinyl alcohol randomly having ethylene as a structural unit of the main chain having a polymerization degree of 800, an ethylene content of 5 mol% and a saponification degree of 93 mol% is added to 2900 g of pure water and stirred at a temperature of 90 ° C. for about 2 hours. And dissolved. The solution was cooled to 28 ° C., 20 g of 35% by weight hydrochloric acid and 115 g of n-butyraldehyde were added thereto, the liquid temperature was lowered to 20 ° C., and this temperature was maintained to conduct an acetalization reaction. The product precipitated out. Thereafter, the liquid temperature was maintained at 30 ° C. for 5 hours to complete the reaction, and neutralization, washing with water and drying were performed by a conventional method to obtain a white powder of a modified polyvinyl acetal resin.
[0128]
The obtained modified polyvinyl acetal resin was treated with DMSO-d. ₆ Dissolved in (dimethyl sulfoxide), ¹³ When the degree of acetalization was measured using C-NMR (nuclear magnetic resonance spectrum), the degree of acetalization was 68 mol%. Moreover, when the glass transition temperature was measured with a differential scanning calorimeter, only one glass transition temperature appeared, and it was completely dissolved in a mixed solution of ethanol / toluene = 1/1 (weight ratio) and methyl ethyl ketone. It was confirmed that the modified polyvinyl acetal resin has ethylene as a constituent unit of the main chain at random.
[0129]
(Examples 2 to 4)
A modified polyvinyl acetal resin was obtained in the same manner as in Example 1, except that the polymerization degree, ethylene content, saponification degree, aldehyde type, and acetalization degree of polyvinyl alcohol were changed as shown in Table 1. . In Example 4, a mixture of modified polyvinyl alcohol / unmodified polyvinyl alcohol = 1/1 (weight ratio) was used. When the glass transition temperature of the obtained modified polyvinyl acetal resin was measured by a differential scanning calorimeter, only one glass transition temperature corresponding to one kind of modified polyvinyl acetal contained appeared, and ethanol / toluene = 1/1 ( It was confirmed that the modified polyvinyl acetal resin had ethylene randomly as a constituent unit of the main chain, because it was completely dissolved in the mixed solution of (weight ratio) and methyl ethyl ketone.
[0130]
(Comparative Examples 1-4)
Except for not including ethylene as a monomer unit, the same as in Examples 1 to 4 except that unmodified polyvinyl alcohol having the same structure as the modified polyvinyl alcohol used in Examples 1 to 4 was used. Thus, a polyvinyl acetal resin having substantially the same degree of acetalization was obtained.
[0131]
[Table 1]

[0132]
<Performance evaluation>
The oxygen permeability coefficient and the thermal decomposability of the polyvinyl acetal resins obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were evaluated by the following methods, and the results are shown in Tables 2 and 3.
[0133]
(Oxygen permeability coefficient measurement)
The polyvinyl acetal resin was added to a mixed solution of ethanol / toluene = 1: 1 (weight ratio) and dissolved so that the resin concentration became 15% by weight. Next, this solution was applied to a polyethylene terephthalate (hereinafter also referred to as PET) film, dried at 50 ° C. for 6 hours, and then a polyvinyl acetal film having a thickness of 50 μm was obtained. Next, the polyvinyl acetal film was subjected to vacuum drying treatment at room temperature for 6 days for measurement. For the measurement, a differential pressure type gas permeability measurement system is used, oxygen gas is used as a test gas, and a test gas pressure is 15 N / cm. ² , Test temperature 25 ° C, gas permeation area 15.2cm ² And the oxygen permeability coefficient was determined.
[0134]
(Pyrolysis measurement)
Tg / DTA measurement at a measurement temperature range of 30 to 700 ° C., a temperature rise temperature of 10 ° C./min, using a platinum pan as an open test container, and an air flow atmosphere and a nitrogen flow atmosphere at a flow rate of 200 ml / min. went.
[0135]
[Table 2]

[0136]
[Table 3]

[0137]
From the results of Table 2, the oxygen permeability coefficient indicates that the polyvinyl acetal resins obtained in Examples 1 to 4 are lower in value than the polyvinyl acetal resins obtained in Comparative Examples 1 to 4, and more difficult to pass oxygen. Show. That is, it can be seen that the modified polyvinyl acetal resin has improved gas barrier properties than the unmodified polyvinyl acetal resin.
[0138]
From the results of Table 3, in terms of thermal decomposability, the polyvinyl acetal resins obtained in Examples 1 to 4 were almost completely pyrolyzed at 700 ° C. from the weight change rate. On the other hand, the polyvinyl acetal resins obtained in Comparative Examples 1 to 4 had a smaller weight change rate than the polyvinyl acetal resins obtained in Examples 1 to 4. That is, it can be seen that the modified polyvinyl acetal resin is more thermally decomposable than the unmodified polyvinyl acetal resin.
[0139]
(Examples 5 to 11)
A modified polyvinyl acetal resin was obtained in the same manner as in Example 1 except that the polymerization degree, ethylene content, saponification degree, aldehyde type, and acetalization degree of polyvinyl alcohol were changed as shown in Table 4. In Examples 9 to 11, a mixture of modified polyvinyl alcohol / unmodified polyvinyl alcohol = 1/1 (weight ratio) was used. When the glass transition temperature of the obtained modified polyvinyl acetal resin was measured by a differential scanning calorimeter, only one glass transition temperature corresponding to one kind of modified polyvinyl acetal contained appeared, and ethanol / toluene = 1/1 ( It was confirmed that the modified polyvinyl acetal resin had ethylene randomly as a constituent unit of the main chain, because it was completely dissolved in the mixed solution of (weight ratio) and methyl ethyl ketone.
[0140]
(Comparative Examples 5-11)
Except for not including ethylene as a monomer unit, the same procedure as in Examples 5 to 11 was performed except that unmodified polyvinyl alcohol having the same structure as that of the modified polyvinyl alcohol used in Examples 5 to 11 was used. A polyvinyl acetal resin having the same degree of acetalization was obtained.
[0141]
<Performance evaluation>
Performance of the polyvinyl acetal resin obtained in Examples 5 to 11 and Comparative Examples 5 to 11, such as solution viscosity, stability of the solution viscosity over time (viscosity change rate), and elongation of the coating film were evaluated by the following methods. The results are shown in Tables 4 and 5.
[0142]
(Solution viscosity and viscosity difference)
The polyvinyl acetal resins obtained in Examples 5 to 11 and Comparative Examples 5 to 11 are added to a mixed solution of ethanol / toluene = 1/1 (weight ratio) and completely dissolved so that the resin concentration becomes 10% by weight. did. Next, the viscosity of this solution was measured at 20 ° C. using a Brookfield type rotational viscometer (initial viscosity).
Next, the solution viscosity of the modified polyvinyl acetal resin obtained in Example 5 and the solution viscosity of the unmodified polyvinyl acetal resin obtained in Comparative Example 5 corresponding to Example 5 were compared. The difference (ratio) of the viscosity was determined.
[0143]
[Equation 3]

[0144]
In formula (3), A represents the viscosity of the modified polyvinyl acetal resin (Example 5), and B represents the viscosity of the unmodified polyvinyl acetal resin (Comparative Example 5).
[0145]
Similarly, the solution viscosity of the modified polyvinyl acetal resin obtained in Examples 6 to 11 and the solution viscosity of the unmodified polyvinyl acetal resin obtained in Comparative Examples 6 to 11 corresponding to Examples 6 to 11, respectively. The difference in viscosity was determined by comparison.
[0146]
(Solution viscosity over time (viscosity change rate))
The solution whose initial viscosity was measured was stored in a thermostatic chamber at 20 ° C. for 1 month, and the viscosity after storage was measured at 20 ° C. using a Brookfield type rotational viscometer. 4).
[0147]
[Expression 4]

[0148]
In formula (4), C represents the viscosity after one month, and D represents the initial viscosity.
[0149]
(Elongation of coating film and difference in elongation)
Films having a thickness of 50 μm were produced by casting using the polyvinyl acetal resins obtained in Examples 5 to 11 and Comparative Examples 5 to 11. This was pulled at a pulling speed of 10 mm / min, and the maximum point elongation at 20 ° C. was measured using an autograph (manufactured by Shimadzu Corporation).
Next, the maximum point elongation of the modified polyvinyl acetal resin obtained in Example 5 and the maximum point elongation of the unmodified polyvinyl acetal resin obtained in Comparative Example 5 corresponding to Example 5 were compared. The difference in elongation (the ratio) was obtained from (5).
[0150]
[Equation 5]

[0151]
In formula (5), E represents the maximum point elongation of the modified polyvinyl acetal resin (Example 5), and F represents the maximum point elongation of the unmodified polyvinyl acetal resin (Comparative Example 5).
[0152]
Hereinafter, similarly, the maximum elongation of the modified polyvinyl acetal resins obtained in Examples 6 to 11 and the unmodified polyvinyl acetal resins obtained in Comparative Examples 6 to 11 corresponding to Examples 6 to 11 respectively. The maximum point elongation was compared to determine the difference in elongation (ratio).
[0153]
[Table 4]

[0154]
[Table 5]

[0155]
From the results of Tables 4 and 5, the unmodified polyvinyl acetal resins obtained in Comparative Examples 5 to 11 are significantly increased in viscosity change rate compared to the modified polyvinyl acetal resins obtained in Examples 5 to 11. . That is, it can be seen that the unmodified polyvinyl acetal resin has poor viscosity stability. Moreover, it can be seen from the difference in viscosity that the modified polyvinyl acetal resin has a significantly lower solution viscosity than the unmodified polyvinyl acetal resin. Moreover, it can be seen from the difference in the elongation of the coating film that the modified polyvinyl acetal resin has a significantly larger elongation than the unmodified polyvinyl acetal resin, and is excellent in flexibility.
[0156]
(Example 12)
<Manufacture of modified polyvinyl acetal resin>
193 g of modified polyvinyl alcohol randomly having ethylene as a structural unit of the main chain having a polymerization degree of 2000, an ethylene content of 5 mol% and a saponification degree of 98 mol% is added to 2900 g of pure water and stirred at a temperature of 90 ° C. for about 2 hours. And dissolved. This solution was cooled to 28 ° C., 20 g of hydrochloric acid having a concentration of 35% by weight was added thereto, and 51 g of acetaldehyde was further added. Next, it cooled to 12 degreeC, n-butyraldehyde 48g was added, the acetalization reaction was performed, and the reaction product was deposited. Thereafter, the liquid temperature was maintained at 60 ° C. for 5 hours to complete the reaction, and neutralization, water washing and drying were performed by a conventional method to obtain a white powder of a modified polyvinyl acetal resin.
[0157]
The obtained modified polyvinyl acetal resin was treated with DMSO-d. ₆ Dissolved in ¹³ When the degree of acetalization was measured using C-NMR, the degree of acetoacetalization was 43 mol%, the degree of butyralization was 30 mol%, and the total degree of acetalization was 73 mol%. Moreover, when the glass transition temperature was measured with a differential scanning calorimeter, only one glass transition temperature appeared, and it was completely dissolved in a mixed solution of ethanol / toluene = 1/1 (weight ratio) and methyl ethyl ketone. It was confirmed that the modified polyvinyl acetal resin has ethylene as a constituent unit of the main chain at random.
[0158]
<Preparation of adhesive composition>
40 g of the modified polyvinyl acetal resin, 62 g of phenol resin (manufactured by Gunei Chemical Co., Ltd., trade name: PL-2205) and 4 g of epoxy resin (manufactured by Shell Chemical Co., Ltd., trade name: Epicoat 828) were mixed with methanol / methyl ethyl ketone / toluene (weight ratio = It was dissolved in 258 g of a mixed solvent of 2: 2: 1) to prepare an adhesive composition.
[0159]
Next, the obtained adhesive composition was applied to a copper foil for a printed circuit board so that the thickness as a solid content was 33 μm, and dried at 140 ° C. for 4 minutes to obtain a copper foil with an adhesive layer. . This copper foil with an adhesive layer was left under conditions of a temperature of 20 ° C. and a humidity of 70% for 3 days. Then, the copper foil with the adhesive layer and the phenol-impregnated paper were 1200 N / cm for 30 minutes at 150 ° C. ² The copper foil laminate was laminated by pressure molding at a pressure of 1 mm.
[0160]
(Examples 13-14, Comparative Examples 12-13)
The adhesive composition was prepared in the same manner as in Example 12 except that the degree of polymerization of the modified polyvinyl alcohol, the ethylene content, the degree of saponification, the type of aldehyde, and the degree of acetalization were changed as shown in Table 6. A copper foil laminate was laminated using this. When the glass transition temperature was measured with a differential scanning calorimeter for the modified polyvinyl acetal resins obtained in Examples 13 and 14, only one glass transition temperature corresponding to one type of modified polyvinyl acetal contained was found, and ethanol / Since it was completely dissolved in a mixed solution of toluene = 1/1 (weight ratio) and methyl ethyl ketone, it was confirmed that the modified polyvinyl acetal resin had ethylene randomly as a constituent unit of the main chain.
[0161]
(Example 15)
<Preparation of adhesive composition>
40 g of a modified polyvinyl acetal resin having ethylene randomly as a structural unit of the main chain prepared in Example 12, 62 g of melamine resin (trade name; Uban 22R) manufactured by Mitsui Chemicals, and epoxy resin (trade name, manufactured by Shell Chemical Co., Ltd.) 4 g of Epicoat 828) was dissolved in 258 g of a mixed solvent of methanol / methyl ethyl ketone / toluene (weight ratio = 2: 2: 1) to prepare an adhesive composition.
[0162]
Next, the obtained adhesive composition was applied to a copper foil for a printed circuit board so that the thickness as a solid content was 33 μm and dried at 140 ° C. for 4 minutes to obtain a copper foil with an adhesive layer. It was. This copper foil with an adhesive layer was left under conditions of a temperature of 20 ° C. and a humidity of 70% for 3 days. Then, the copper foil with the adhesive layer and the phenol-impregnated paper were 1200 N / cm for 30 minutes at 150 ° C. ² The copper foil laminate was laminated by pressure molding at a pressure of 1 mm.
[0163]
(Examples 16-17, Comparative Examples 14-15)
The adhesive composition was prepared in the same manner as in Example 15 except that the degree of polymerization of the modified polyvinyl alcohol, the ethylene content, the degree of saponification, the type of aldehyde, and the degree of acetalization were changed as shown in Table 6. A copper foil laminate was laminated using this.
[0164]
(Example 18)
<Adjustment of adhesive composition>
7 g of a modified polyvinyl acetal resin having ethylene randomly as a structural unit of the main chain produced in Example 12, 60 g of an epoxy resin (manufactured by Shell Chemical Co., Ltd., trade name; Epicoat 828) and melamine resin (manufactured by Mitsui Chemicals, trade name; 5 g of Euban 22R) was dissolved in 258 g of a mixed solvent of methanol / methyl ethyl ketone / toluene (weight ratio = 2: 2: 1) to prepare an adhesive composition.
[0165]
Next, the obtained adhesive composition was applied to a copper foil for a printed circuit board so that the thickness as a solid content was 33 μm and dried at 140 ° C. for 4 minutes to obtain a copper foil with an adhesive layer. It was. This copper foil with an adhesive layer was left under conditions of a temperature of 20 ° C. and a humidity of 70% for 3 days.
Thereafter, the copper foil with the adhesive layer and a prepreg impregnated with a glass cloth with an epoxy resin at 1200 ° C. for 30 minutes, 1200 N / cm ² The copper foil laminate was laminated by pressure molding at a pressure of 1 mm.
[0166]
(Examples 19-20, Comparative Examples 16-17)
The adhesive composition was prepared in the same manner as in Example 15 except that the degree of polymerization of the modified polyvinyl alcohol, the ethylene content, the degree of saponification, the type of aldehyde, and the degree of acetalization were changed as shown in Table 6. A copper foil laminate was laminated using this.
[0167]
<Performance evaluation>
For the copper foil laminates obtained in Examples 12 to 20 and Comparative Examples 12 to 17, solder heat resistance and peel strength were measured in accordance with JISC-6485. The test temperature was 260 ° C. for solder heat resistance and 150 ° C. for peel strength. The results are shown in Table 6.
[0168]
[Table 6]

[0169]
From the results in Table 6, the copper foil laminates obtained in Examples 12 to 20 were significantly higher than the copper foil laminates obtained in Comparative Examples 12 to 17 in both the solder heat resistance and the peel strength.
[0170]
(Example 21)
<Manufacture of modified polyvinyl acetal resin>
193 g of modified polyvinyl alcohol having ethylene as a main chain constituent unit having a polymerization degree of 300, an ethylene content of 5 mol% and a saponification degree of 98 mol% is added to 2900 g of pure water and stirred at a temperature of 90 ° C. for about 2 hours. And dissolved. This solution was cooled to 28 ° C., 20 g of hydrochloric acid having a concentration of 35% by weight and 115 g of n-butyraldehyde were added thereto, the liquid temperature was lowered to 20 ° C., and this temperature was maintained to carry out an acetalization reaction. The product precipitated out. Thereafter, the liquid temperature was maintained at 30 ° C. for 5 hours to complete the reaction, and neutralization, washing with water and drying were performed by a conventional method to obtain a white powder of a modified polyvinyl acetal resin.
[0171]
The obtained modified polyvinyl acetal resin was treated with DMSO-d. ₆ Dissolved in ¹³ When the degree of acetalization was measured using C-NMR, the degree of acetalization was 68 mol%. Moreover, when the glass transition temperature was measured with a differential scanning calorimeter, only one glass transition temperature appeared, and it was completely dissolved in a mixed solution of ethanol / toluene = 1/1 (weight ratio) and methyl ethyl ketone. It was confirmed that the modified polyvinyl acetal resin has ethylene as a constituent unit of the main chain at random.
[0172]
<Manufacture of ink>
4.4 g of the modified polyvinyl acetal resin and 25.6 g of ethanol are placed in a glass bottle and stirred for 24 hours. Then, 10 g of pigment and glass beads are added, and the mixture is shaken for 90 minutes with a paint shaker (manufactured by Red Devil). The pigment was dispersed. Next, 8.5 g of ethyl acetate was additionally added, and a small amount of additive was further added and shaken for 60 minutes to prepare an ink. The glass beads were added in an amount 1.5 times the total weight of the modified polyvinyl acetal resin, ethanol and ethyl acetate.
[0173]
(Examples 22 to 27, Comparative Examples 18 to 24)
An ink was prepared in the same manner as in Example 21 except that the polymerization degree, ethylene content, saponification degree, aldehyde type, and acetalization degree of the modified polyvinyl alcohol were changed as shown in Table 7. When the glass transition temperature was measured with a differential scanning calorimeter for the modified polyvinyl acetal resins obtained in Examples 22 to 27, only one glass transition temperature corresponding to one type of modified polyvinyl acetal contained was found. Since it was completely dissolved in a mixed solution of toluene = 1/1 (weight ratio) and methyl ethyl ketone, it was confirmed that the modified polyvinyl acetal resin had ethylene randomly as a constituent unit of the main chain.
[0174]
<Performance evaluation>
The inks obtained in Examples 21 to 27 and Comparative Examples 18 to 24 were evaluated for the viscosity over time, the adhesion to the substrate, and the oxygen permeability by the following methods. The results are shown in Table 7.
[0175]
(Measurement of ink viscosity over time)
A shear rate of 1000 s using a mechanical spectrometer (Rheometric, RMS-800) ^-1 The viscosity (mPa · s) of the ink at a measurement temperature of 25 ° C. was measured. A biaxial cylindrical type was used for the geometry. The measurement was carried out after inserting the required amount of the sample into a biaxial cylindrical container with a pipette and leaving it to stand for 5 minutes with pre-shearing. Subsequently, each steady shear rate was applied to the sample. First, the steady shear rate is low (1 s ^-1 ) To high speed side (1000s ^-1 The shear rate was applied to the lower speed side from the higher speed side. The viscosity behavior of the fluid is a shear rate of 1000 s after applying a high shear rate. ^-1 The viscosity at that time was defined as a viscosity value (A).
As an acceleration acceleration test for reproducing the ink state after 6 months, after leaving at 40 ° C. for 72 hours, the viscosity was measured by the same method as described above to obtain a viscosity value (B).
From the viscosity value (A) and the viscosity value (B), the ink viscosity change rate (viscosity ratio) was calculated.
[0176]
(Measurement of adhesion to substrate)
The ink was applied onto a 30 μm-thick polypropylene film with a bar coater to form a 3 μm-thick ink layer, and then left for 3 days at a temperature of 20 ° C. and a humidity of 90%. After leaving, a cellophane tape was applied to the coated surface and then peeled off. The remaining amount of ink on the film was visually observed and evaluated in the following three stages.
○: The ink layer was completely left on the film even after the cellophane tape was peeled off.
(Triangle | delta): A part of ink layer had adhered to the cellophane tape.
X: Most of the ink layer adhered to the cellophane tape.
[0177]
(Oxygen permeability measurement)
The ink was applied to a PET film and dried at 50 ° C. for 6 hours to obtain an ink film having a thickness of 50 μm. Next, this ink film was dried under reduced pressure for 6 days at room temperature and subjected to measurement. For the measurement, a differential pressure type gas permeability measurement system is used, oxygen gas is used as a test gas, and a test gas pressure is 15 N / cm. ² , Test temperature 25 ° C, gas permeation area 15.2cm ² And the oxygen permeability coefficient was determined.
[0178]
[Table 7]

[0179]
From the results shown in Table 7, the inks obtained in Examples 21 to 27 were much lower in viscosity change with time and oxygen permeability coefficient than the inks obtained in Comparative Examples 18 to 24. The adhesiveness was significantly better.
[0180]
(Example 28)
<Manufacture of modified polyvinyl acetal resin>
193 g of modified polyvinyl alcohol having ethylene as a main chain constituent unit having a polymerization degree of 500, an ethylene content of 5 mol% and a saponification degree of 98 mol% is added to 2900 g of distilled water and stirred at a temperature of 90 ° C. for about 2 hours. And dissolved. This solution was cooled to 28 ° C., 20 g of hydrochloric acid having a concentration of 35% by weight and 125 g of n-butyraldehyde were added thereto, the liquid temperature was lowered to 20 ° C., and this temperature was maintained to carry out an acetalization reaction. The product precipitated out. Thereafter, the liquid temperature was maintained at 30 ° C. for 5 hours to complete the reaction, washed with distilled water, and sodium bicarbonate was added to the modified polyvinyl acetal resin dispersion after washing to adjust the solution to pH 8. Next, the solution is kept at 60 ° C. for 5 hours and then cooled, washed with 100 times the amount of distilled water with respect to the solid content, and further kept at 50 ° C. for 5 hours and then washed with 100 times the amount of distilled water. And dehydrated and dried.
[0181]
The obtained modified polyvinyl acetal resin was treated with DMSO-d. ₆ Dissolved in ¹³ When the degree of acetalization was measured using C-NMR, the degree of acetalization was 75 mol%. The residual aldehyde content was 10 ppm and the residual water content was 2.0% by weight. When the glass transition temperature of the modified polyvinyl acetal resin obtained was measured with a differential scanning calorimeter, only one glass transition temperature appeared, and the mixture was completely mixed with ethanol / toluene = 1/1 (weight ratio) and methyl ethyl ketone. Therefore, it was confirmed that the modified polyvinyl acetal resin has ethylene as a constituent unit of the main chain at random. In addition, the measurement of the said aldehyde amount measured the modified polyvinyl acetal resin by heat-extracting with a heating furnace, and measured the extract using the gas chromatography. The moisture content was measured using a Karl Fischer moisture meter.
[0182]
<Preparation of coating solution for heat-developable photosensitive material film>
The above modified polyvinyl acetal resin (5.0 g), silver behenate (5.0 g), and methyl ethyl ketone (40 g) are mixed with a ball mill for 24 hours. Further, 0.2 g of N-lauryl-1-hydroxy-2-naphthamide is added and ground again with a ball mill. Thus, a coating solution was obtained.
[0183]
<Preparation of heat-developable photosensitive material film>
The coating solution was applied on a polyester substrate so that the thickness after drying was 10 μm and dried. On this coated surface, a solution composed of 0.5 g of N, N monodimethyl-p-phenylenediamine / lead sulfate, 2 g of polyvinylpyrrolidone and 30 ml of methanol was applied and dried so that the thickness after drying was 1 μm. Thus, a heat-developable photosensitive material film was prepared by laminating.
[0184]
(Examples 29 to 34, Comparative Examples 25 to 28)
Thermal development was carried out in the same manner as in Example 28, except that the degree of polymerization, degree of saponification, type of aldehyde, degree of acetalization, degree of residual water, amount of residual aldehyde of the modified polyvinyl acetal resin were changed as shown in Table 8. Photosensitive film was prepared. When the glass transition temperature was measured with a differential scanning calorimeter for the modified polyvinyl acetal resins obtained in Examples 29 to 34, only one glass transition temperature corresponding to one type of modified polyvinyl acetal contained was found, and ethanol / Since it was completely dissolved in a mixed solution of toluene = 1/1 (weight ratio) and methyl ethyl ketone, it was confirmed that the modified polyvinyl acetal resin had ethylene randomly as a constituent unit of the main chain.
[0185]
<Performance evaluation>
The performance evaluation of the heat-developable photosensitive material films obtained in Examples 28 to 34 and Comparative Examples 25 to 28 was performed by the following method. The results are shown in Table 8.
[0186]
(Preservation of raw film)
The heat-developable photosensitive material film was stored at a humidity of 90% and a temperature of 20 ° C. for 1 month. Thereafter, the photosensitive film was exposed through a gradation pattern film with a 250 watt high-pressure mercury lamp for 0.3 seconds from a distance of 20 cm, and then heated for 3 seconds using a 110 ° C. hot plate to obtain a cyan pattern image. This was evaluated according to the following three levels.
○: There was no fog and the sharpness was good.
Δ: Slight fogging occurred and the sharpness was poor.
X: Many foggings occurred and the sharpness was poor.
[0187]
(Blocking property of raw film)
The heat-developable photosensitive material film was cut into A4 size, 100 sheets were stacked, and stored for 1 month at a humidity of 90% and a temperature of 40 ° C. The blocking level at this time was evaluated according to the following three levels.
◯: No blocking at all, and each piece peeled cleanly.
(Triangle | delta): A part of film blocked and it was a part which was hard to peel.
X: Most of the film was blocking and peeling was quite difficult.
[0188]
(Storability of film after image formation)
The photosensitive film was exposed through a gradation pattern film with a 250 watt high-pressure mercury lamp for 0.3 seconds from a distance of 20 cm, and then heated for 3 seconds using a hot plate at 110 ° C. to obtain a cyan pattern image. Thereafter, it was stored for 1 month at a humidity of 90% and a temperature of 40 ° C. The state of the film surface at this time was evaluated according to the following three levels.
○: An image that was the same as before storage was formed.
Δ: Some parts were white, unlike before storage.
X: Unlike a part before storage, a considerable part was whitened.
[0189]
[Table 8]

[0190]
From the results of Table 8, the heat-developable photosensitive material films obtained in Examples 28-34 are more stable than the heat-developable photosensitive material films obtained in Comparative Examples 25-28. It was excellent in blocking properties and film storage stability after image formation.
[0191]
(Example 35)
<Manufacture of modified polyvinyl acetal resin>
193 g of modified polyvinyl alcohol randomly having ethylene as a structural unit of the main chain having a polymerization degree of 800, an ethylene content of 5 mol% and a saponification degree of 93 mol% is added to 2900 g of pure water and stirred at a temperature of 90 ° C. for about 2 hours. And dissolved. The solution was cooled to 28 ° C., 20 g of 35% by weight hydrochloric acid and 115 g of n-butyraldehyde were added thereto, the liquid temperature was lowered to 20 ° C., and this temperature was maintained to conduct an acetalization reaction. The product precipitated out. Thereafter, the liquid temperature is maintained at 30 ° C. for 5 hours to complete the reaction, and neutralization, water washing and drying are performed by a conventional method to obtain a white powder of a modified polyvinyl acetal resin having ethylene randomly as a main chain constituent unit. It was.
[0192]
The obtained modified polyvinyl acetal resin was treated with DMSO-d. ₆ Dissolved in ¹³ When the degree of acetalization was measured using C-NMR, the degree of acetalization was 68 mol%. Moreover, when the glass transition temperature was measured with a differential scanning calorimeter, only one glass transition temperature appeared, and it was completely dissolved in a mixed solution of ethanol / toluene = 1/1 (weight ratio) and methyl ethyl ketone. It was confirmed that the modified polyvinyl acetal resin has ethylene as a constituent unit of the main chain at random.
[0193]
<Manufacture of slurry composition for ceramic green sheet>
10 parts by weight of the modified polyvinyl acetal resin was added to a mixed solvent of 30 parts by weight of toluene and 15 parts by weight of ethanol and dissolved by stirring. To this resin solution, 3 parts by weight of dibutyl phthalate was added as a plasticizer and dissolved by stirring. A slurry composition for a ceramic green sheet, in which 100 parts by weight of barium titanate powder having an average particle size of 0.3 μm was added as a ceramic powder to the resin solution thus obtained and mixed for 36 hours by a ball mill to disperse the barium titanate powder. Got.
[0194]
<Manufacture of ceramic green sheets>
The ceramic green sheet slurry composition is applied to a release-treated polyester film at a thickness of about 6 μm, air-dried at room temperature for 30 minutes, and further dried at 60 to 80 ° C. for 15 hours with a hot air dryer. The solvent was dried to obtain a thin ceramic green sheet having a thickness of 3 μm.
[0195]
(Examples 36 to 41)
Example 34 except that the polymerization degree of polyvinyl alcohol, ethylene content, saponification degree, aldehyde type, acetalization degree, average particle diameter of ceramic powder, and plasticizer were changed as shown in Table 9. Similarly, a modified polyvinyl acetal resin having a random ethylene as a main chain constituent unit, a slurry composition, and a ceramic green sheet were manufactured. In Examples 39 to 41, in the production of the modified polyvinyl acetal resin, a mixture of modified polyvinyl alcohol / unmodified polyvinyl alcohol = 1/1 (weight ratio) was used. When the glass transition temperature of the modified polyvinyl acetal resins obtained in Examples 36 to 41 was measured with a differential scanning calorimeter, only one glass transition temperature corresponding to one kind of the modified polyvinyl acetal appeared, and ethanol / Since it was completely dissolved in a mixed solution of toluene = 1/1 (weight ratio) and methyl ethyl ketone, it was confirmed that the modified polyvinyl acetal resin had ethylene randomly as a constituent unit of the main chain.
[0196]
(Comparative Examples 29-35)
Except that ethylene is not included as a monomer unit, the same procedure as in Examples 35 to 41 was performed except that unmodified polyvinyl alcohol having the same structure as that of the modified polyvinyl alcohol used in Examples 35 to 41 was used. Then, a polyvinyl acetal resin having the same degree of acetalization was produced, and a slurry composition and a ceramic green sheet were produced using the polyvinyl acetal resin.
[0197]
<Performance evaluation>
The viscosity and viscosity stability of the slurry compositions obtained in Examples 35 to 41 and Comparative Examples 29 to 35, and the peelability, adhesiveness, and elongation of the ceramic green sheets were evaluated by the following methods, and the results are shown. 9 and Table 10. The hygroscopicity of the ceramic green sheets obtained in Examples 35 to 41 and Comparative Examples 29 to 35 and the amount of pyrolysis residue after sintering were evaluated by the following methods. The results are shown in Table 11.
[0198]
(Viscosity of slurry composition and difference in viscosity)
The viscosities of the slurry compositions obtained in Examples 35 to 41 and Comparative Examples 29 to 35 were measured at 20 ° C. using a Brookfield type rotational viscometer to obtain an initial viscosity.
Next, the viscosity of the slurry composition obtained in Example 35 and the viscosity of the slurry composition obtained in Comparative Example 29 corresponding to Example 35 were compared, and the difference in viscosity ( Ratio).
[0199]
[Formula 6]

[0200]
In formula (6), G represents the viscosity of the slurry composition (Example 35) prepared from the modified polyvinyl acetal resin, and H represents the viscosity of the slurry composition (Comparative Example 29) prepared from the unmodified polyvinyl acetal resin. Represents.
Similarly, the viscosity of the slurry compositions obtained in Examples 36 to 41 was compared with the viscosity of the slurry compositions obtained in Comparative Examples 30 to 35 corresponding to Examples 36 to 41, respectively. The difference was determined.
[0201]
(Stability of slurry viscosity over time (viscosity change rate))
The slurry solution whose initial viscosity was measured was stored in a thermostatic chamber at 20 ° C. for 1 month, and the viscosity after storage was measured at 20 ° C. using a Brookfield type rotational viscometer. Obtained by (7).
[0202]
[Expression 7]

[0203]
In formula (7), I represents the viscosity after one month, and J represents the initial viscosity.
[0204]
(Peelability of ceramic green sheets)
The ceramic green sheets obtained in Examples 35 to 41 and Comparative Examples 29 to 35 were cut into 10 cm squares, 10 sheets were stacked on a PET film, 70 ° C., pressure 1500 N / cm. ² After laminating under hot pressure conditions for 10 minutes, the peeled state when the ceramic green sheet was peeled from the PET film was evaluated in the following three stages by a sensory test mainly consisting of visual observation.
○: There was no ceramic green sheet adhering to the PET film, and there were no cuts or cracks in the ceramic green sheet.
(Triangle | delta): The ceramic green sheet adhering to PET film was partially recognized, or the cutting | disconnection and crack of the ceramic green sheet were partially recognized.
X: Many ceramic green sheets adhering to the PET film were recognized, or many cuts and cracks of the ceramic green sheets were recognized.
[0205]
(Adhesiveness of ceramic green sheets)
The ceramic green sheets obtained in Examples 35 to 41 and Comparative Examples 29 to 35 were cut into 10 cm square and stacked 200 sheets, 70 ° C., pressure 1500 N / cm. ² After laminating under hot pressure conditions for 10 minutes, the adhesion between the layers of the ceramic green sheet was evaluated in the following three stages by a sensory test mainly consisting of visual observation.
○: No delamination was observed at all, and the layers were firmly bonded.
Δ: Partial delamination was observed.
X: A considerable amount of delamination was observed.
[0206]
(Sheet elongation (difference in elongation))
The ceramic green sheets obtained in Examples 35 to 41 and Comparative Examples 29 to 35 were pulled at a pulling speed of 10 mm / min in an environment of 20 ° C., and the maximum point elongation was performed using an autograph (manufactured by Shimadzu Corporation). The degree was measured.
Next, the elongation of the maximum point of the ceramic green sheet obtained in Example 35 was compared with the elongation of the maximum point of the ceramic green sheet obtained in Comparative Example 29 corresponding to Example 35. The difference in elongation (the ratio) was obtained from (8).
[0207]
[Equation 8]

[0208]
In the formula (8), K represents the maximum elongation of a ceramic green sheet (Example 35) prepared from a modified polyvinyl acetal resin, and L represents a ceramic green sheet prepared from an unmodified polyvinyl acetal resin (Example 35). It represents the elongation at the maximum point in Comparative Example 29).
[0209]
Similarly, the elongation of the maximum point of the ceramic green sheets obtained in Examples 36 to 41 and the elongation of the maximum point of the ceramic green sheets obtained in Comparative Examples 30 to 35 corresponding to Examples 36 to 41, respectively. The degree was compared.
[0210]
[Table 9]

[0211]
[Table 10]

[0212]
From the results of Tables 9 and 10, the slurry compositions obtained in Examples 35 to 41 have a significantly lower slurry viscosity than the ceramic green sheets obtained in Comparative Examples 29 to 35, and the slurry viscosity is stable over time. The sex was also very stable.
In addition, the ceramic green sheets obtained in Examples 35 to 41 were good in both peelability and adhesiveness. On the other hand, it was confirmed that the ceramic green sheets obtained in Comparative Examples 31, 32, 34, and 35 were hard and cracked during peeling, and were peeled off at a considerable portion between the sheet layers.
Moreover, the ceramic green sheets obtained in Examples 35 to 41 were ceramic green sheets that stretched better than the ceramic green sheets obtained in Comparative Examples 29 to 35, and were excellent in flexibility.
[0213]
(Hygroscopicity of green sheet)
The ceramic green sheets obtained in Examples 35 to 41 and Comparative Examples 29 to 35 were cut into 10 cm squares, left to stand at a humidity of 90% and a temperature of 20 ° C. for 5 days, and the weight was measured before and after being left. The hygroscopicity of the ceramic green sheet was determined by the following formula (9) from the weight change before and after standing.
[0214]
[Equation 9]

[0215]
In formula (9), M represents the weight of the ceramic green sheet after being left, and N represents the weight of the green sheet before being left.
[0216]
(Pyrolysis residue of modified polyvinyl acetal resin)
The amount of the decomposition residue after heating 10 mg of the modified polyvinyl acetal resins obtained in Examples 35 to 41 and Comparative Examples 29 to 35 in a nitrogen atmosphere at a temperature rising rate of 10 ° C./min from room temperature to 700 ° C. is determined. It was.
[0217]
(Thermal decomposition residue of ceramic green sheet)
The ceramic green sheets obtained in Examples 35 to 41 and Comparative Examples 29 to 35 were cut into 10 cm square and 500 sheets were stacked, temperature 70 ° C., pressure 1500 N / cm. ² For 10 minutes to obtain a laminated body of ceramic green sheets. Next, the ceramic green sheet was heated to 450 ° C. at a temperature rising rate of 3 ° C./min and maintained at a constant temperature for 5 hours in a nitrogen atmosphere, and further heated to 1350 ° C. at a temperature rising rate of 5 ° C./min. The ceramic was completely sintered for 10 hours. After cooling the ceramic green sheet to room temperature, the sheet was divided in half, and the state of the ceramic green sheet in the vicinity of 250 layers was observed with an electronic forehead mirror and evaluated in the following three steps.
○: Sintered uniformly and there was nothing other than ceramic powder.
(Triangle | delta): A black spot-like thing was rarely confirmed in the ceramic green sheet.
X: Quite many black dots were confirmed in the ceramic green sheet.
[0218]
[Table 11]

[0219]
From the results of Table 11, the ceramic green sheets obtained in Examples 35-41 are significantly lower in hygroscopicity than the ceramic green sheets obtained in Comparative Examples 29-35, and the modified polyvinyl acetal resin contained therein. The pyrolysis residue is very small, and the pyrolysis residue of the ceramic green sheet itself is very good, and black carbon resulting from the pyrolysis residue was not confirmed.
[0220]
【The invention's effect】
According to the present invention, flexibility, adhesion to a resin substrate under high humidity, heat resistance, thermal decomposability, moisture resistance, toughness, low oxygen permeability, and moderate adhesion, Modified polyvinyl acetal resin having a low viscosity when made into a solution and excellent viscosity stability over time, and an adhesive composition, ink, coating composition, heat-developable photosensitive material, and slurry for ceramic green sheets using the same A composition and a ceramic green sheet can be provided.

Claims (4)

As a structural unit of the main chain, it is obtained by acetalizing a modified polyvinyl alcohol having ethylene as a main chain constituent unit randomly and having an ethylene content of 1 to 20 mol% and a saponification degree of 80 mol% or more. An ink comprising a modified polyvinyl acetal resin having ethylene randomly . As a structural unit of the main chain, it is obtained by acetalizing a modified polyvinyl alcohol having ethylene as a main chain constituent unit randomly and having an ethylene content of 1 to 20 mol% and a saponification degree of 80 mol% or more. A paint comprising a modified polyvinyl acetal resin having ethylene at random . As a structural unit of the main chain, it is obtained by acetalizing a modified polyvinyl alcohol having ethylene as a main chain constituent unit randomly and having an ethylene content of 1 to 20 mol% and a saponification degree of 80 mol% or more. An adhesive comprising: a modified polyvinyl acetal resin having ethylene at random; and at least one thermosetting resin selected from the group consisting of a phenol resin, an epoxy resin, and a melamine resin. As a structural unit of the main chain, it is obtained by acetalizing a modified polyvinyl alcohol having ethylene as a main chain constituent unit randomly and having an ethylene content of 1 to 20 mol% and a saponification degree of 80 mol% or more. A heat-developable photosensitive material comprising a modified polyvinyl acetal resin having ethylene randomly .