JP3851074B2 - Method for producing adhesive spacer for liquid crystal display panel - Google Patents

Description

【００１５】
（ここで、Ｒ^aは水素原子またはメチル基を示し；Ｒ^bは、置換基を有していても良い炭素数１〜２０の２価の有機基を示し；Ｒ^cは、水素原子と、炭素数１〜５のアルキル基と、炭素数２〜５のアシル基とからなる群から選ばれる少なくとも１つの１価基を示す。Ｒ¹は、炭素数１〜５のアルキル基とフェニル基とからなる群から選ばれた少なくとも１種の１価の基を示す。ｌは１または２であり、ｐは０または１である。）
と、次の一般式（２）：
【００１６】
【化２】

【００１７】
（ここで、Ｒ^dは水素原子またはメチル基を示し；Ｒ^eは、水素原子と、炭素数１〜５のアルキル基と、炭素数２〜５のアシル基とからなる群から選ばれる少なくとも１つの１価基を示す。Ｒ²は、炭素数１〜５のアルキル基とフェニル基とからなる群から選ばれた少なくとも１種の１価の基を示す。ｍは１または２であり、ｑは０または１である。）
と、次の一般式（３）：
【００１８】
【化３】

【００１９】
（ここで、Ｒ^fは水素原子またはメチル基を示し；Ｒ^gは、置換基を有していても良い炭素数１〜２０の２価の有機基を示し；Ｒ^hは、水素原子と、炭素数１〜５のアルキル基と、炭素数２〜５のアシル基とからなる群から選ばれる少なくとも１つの１価基を示す。Ｒ³は、炭素数１〜５のアルキル基とフェニル基とからなる群から選ばれた少なくとも１種の１価の基を示す。ｎは１または２であり、ｒは０または１である。）
とからなる群から選ばれる少なくとも１つの一般式で表される化合物またはその誘導体であることが好ましい。
【００２０】
前記重合工程は、前記縮合工程中および／または前記縮合工程後に、ラジカル重合性基をラジカル重合反応させて粒子を得る工程であることが好ましい。
前記熱処理工程は、前記重合工程で生成した重合体粒子を８００℃以下、より好ましくは１００〜６００℃の温度で乾燥および焼成する工程であり、たとえば、１０容量％以下の酸素濃度を有する雰囲気中や減圧下で行われることが好ましい。
上記の縮合工程、重合工程および熱処理工程から選ばれる少なくとも１つの工程中および／または後に、生成した前記原料粒子を着色する着色工程をさらに含んでいてもよく、詳しくは、前記原料粒子は染料および顔料からなる群から選ばれる少なくとも１つ等を含むことで着色されていてもよい。その色は、光が透過しにくいか、または、透過しない色が、接着性スペーサー自身の光抜けを防止でき画質のコントラストを向上できる点で好ましい。光が透過しにくいか、または、透過しない色としては、たとえば、黒、濃青、紺、紫、青、濃緑、緑、茶、赤等の色を好ましく挙げることができるが、特に好ましくは、黒、濃青、紺色である。なお、染料および／または顔料は、単に原料粒子に含まれるものでもよく、あるいは、染料および／または顔料と原料粒子を構成するマトリックスとが化学結合によって結び付けられた構造を有するものでもよいが、特にこれらに限定されない。
【００２１】
前記染料は、着色しようとする色に応じて適宜選択して使用され、たとえば、染色方法によって分類された、分散染料、酸性染料、塩基性染料、反応染料、硫化染料等が挙げられる。これらの染料の具体例は、「化学便覧応用化学編 日本化学会編」（１９８６年丸善株式会社発行）の１３９９頁〜１４２７頁、「日本化薬染料便覧」（１９７３年日本化薬株式会社発行）に記載されている。
原料粒子を染色する方法としては、従来公知の方法がとられる。たとえば、上記の「化学便覧応用化学編 日本化学会編」や「日本化薬染料便覧」に記載されている方法等で行うことができる。
【００２２】
前記顔料としては、特に限定はされないが、たとえば、カーボンブラック、鉄黒、クロムバーミリオン、モリブデン赤、べんがら、黄鉛、クロム緑、コバルト緑、群青、紺青などの無機顔料；フタロシアニン系、アゾ系、キナクリドン系などの有機顔料が挙げられる。なお、前記顔料は、その平均粒子径が０．４μｍ以下でないと、原料粒子中に導入されない場合があるので、この場合は染料を使用する方が好ましい。前記原料粒子が着色されている場合、液晶表示板用スペーサーとして用いると、バックライトの光抜けを防止でき、液晶表示板の画質向上を達成することができる。
【００２３】
上記の縮合工程、重合工程および熱処理工程から選ばれた少なくとも１種の工程中および／または後に、生成した前記原料粒子を表面処理する表面処理工程をさらに含んでいても良い。
前記表面処理に用いる表面処理剤としては、特に限定されないが、下記一般式（４）〜（６）から選ばれる少なくとも１種のシラン化合物が好ましい。
ＳｉＸ₄ （４）
Ｒ⁴ＳｉＸ₃ （５）
Ｒ⁵Ｒ⁶ＳｉＸ₂ （６）
（ここで、Ｘは塩素原子、水素原子、炭素数１〜５のアルコキシ基および炭素数２〜５のアシロキシ基から選ばれた少なくとも１種；Ｒ⁴およびＲ⁵は、いずれも、炭素数１〜２２のアルキル基および炭素数６〜２２のアリール基から選ばれる少なくとも１種であり、その基の中の１つ以上の水素原子が、アミノ基、メルカプト基、アルキレンオキシド基、エポキシ基、シアノ基、塩素原子およびフッ素原子から選ばれる少なくとも１種で置換されていても良い；Ｒ⁶は、炭素数１〜５のアルキル基とフェニル基とからなる群から選ばれる少なくとも１種の１価の基である。）
前記シラン化合物のうち、一般式（４）で示されるシラン化合物や、Ｒ⁴やＲ⁵がアミノ基を置換基として有するものである一般式（５）または（６）で示されるシラン化合物で表面処理されると、特に乾式散布性に優れるため好ましい。
【００２４】
本発明における原料粒子は、例えば、水相中においては、その水相のｐＨを調整した場合、ゼータ電位としてプラスおよびマイナスのどちらもとり得ることが好ましい。例えば、原料粒子が上述した有機質無機質複合体粒子の場合、ｐＨが３以下においてプラス、ｐＨが３〜１４おいてマイナスとなる。
また、水相のｐＨを調整して、このゼータ電位をさらに詳細に調製し、原料粒子に所望の電荷符号および所望の電荷量を持たせるためには、原料粒子を適当なイオン性の処理剤で処理する、あるいは適当なイオン性の単量体、重合開始剤および乳化剤から選ばれる少なくとも１種の成分を含む原料を使用することが好ましい。
【００２５】
前記イオン性の単量体としては、特に限定されるわけではないが、後述の熱可塑性樹脂微粒子の合成に好ましく用いるイオン性単量体と同様であることが好ましく、原料粒子を合成するための単量体成分中に、０．００１〜１００ｗｔ％含まれることが好ましく、より好ましくは０．１〜３０ｗｔ％、さらに好ましくは０．１〜１０ｗｔ％である。イオン性単量体は過剰であっても不足であっても、ヘテロ凝集の際に問題となるため好ましくない。
前記イオン性の重合開始剤および乳化剤としては、特に限定されるわけではないが、アニオン性やカチオン性等の各種イオン性の重合開始剤および乳化剤を好ましく挙げることができる。
【００２６】
前記イオン性の処理剤としては、特に限定されるわけではないが、各種のイオン性界面活性剤、イオン性ポリマーおよびシランカップリング剤等を好ましく挙げることができる。これらイオン性の処理剤は、原料粒子の合成時に添加してもよいし、合成後の表面処理の際に用いられてもよい。
また前記イオン性単量体および前記イオン性界面活性剤は、両性単量体および両性界面活性剤でもよい。
（熱可塑性樹脂微粒子）
本発明にかかる接着性スペーサーについて、前記接着層は熱可塑性樹脂微粒子からなることが好ましく、前記熱可塑性樹脂微粒子を溶融させてなるものがより好ましい。前記接着層は、本発明の接着性スペーサーが加熱・加圧処理された場合、電極基板等に対する接着剤として好ましく作用する。
【００２７】
熱可塑性樹脂微粒子に含まれる熱可塑性樹脂としては、上記のように接着剤として作用するものであれば特に限定されるわけではないが、例えば、エチレン性不飽和単量体の単独重合体または共重合体を含む樹脂等を好ましく挙げることができる。
前記エチレン性不飽和単量体としては、特に限定はされないが、たとえば、エチレン、プロピレン、塩化ビニル、酢酸ビニル、スチレン、ビニルトルエン、α−メチルスチレン、（メタ）アクリル酸エステル（たとえば、メチル（メタ）アクリレート、エチル（メタ）アクリレート、ｎ−プロピル（メタ）アクリレート、イソプロピル（メタ）アクリレート、ブチル（メタ）アクリレート、ヘキシル（メタ）アクリレート、ラウリル（メタ）アクリレート、ステアリル（メタ）アクリレート、シクロヘキシル（メタ）アクリレート、２−エチルヘキシル（メタ）アクリレート、グリシジル（メタ）アクリレート、トリフルオロプロピル（メタ）アクリレート等を好ましく挙げることができる。これらの中でも、エチレン性不飽和単量体が、芳香族残基（たとえば、フェニル基等）、水素結合可能な残基（エステル基等）を含有していると、配向膜との分子間力が大きくなり、前記電極基盤基板等への接着性が高くなるため好ましく、（メタ）アクリル酸エステルおよび／またはスチレンを含むことがさらに好ましい。
【００２８】
熱可塑性樹脂としては、接着性をより向上させる観点からは、エポキシ樹脂、（メタ）アクリレートをモノマー成分に含む（メタ）アクリル系樹脂、スチレン化合物をモノマー成分に含むスチレン系樹脂、および、スチレン化合物と（メタ）アクリレートとをモノマー成分に含む（メタ）アクリル−スチレン系樹脂からなる各種ポリマー群の中から選ばれた少なくとも１種を含んでなることが特に好ましい。
前記（メタ）アクリル酸エステルおよび／またはスチレンを重合して熱可塑性樹脂微粒子を製造する場合、ソープフリー重合（ソープフリー乳化重合）して得られるものが好ましく、理由としては、前記ソープフリー重合（ソープフリー乳化重合）では界面活性剤等の導電性不純物を使用しないため、液晶表示板の信頼性が向上し易いからである。
【００２９】
前記熱可塑性樹脂としては、上記のものに限定されるわけではなく、例えば、ポリエチレンテレフタラート、ポリブチレンテレフタラート等のポリエステル；各種ポリアミド；各種ポリカーボネート；各種エポキシ樹脂等も好ましく挙げることができる。
熱可塑性樹脂微粒子に用いる前記熱可塑性樹脂としては、これらを１種のみ使用しても、２種以上併用してもよい。また、熱可塑性樹脂微粒子からなる前記接着層は１層であっても２層以上であってもよい。
熱可塑性樹脂微粒子に用いる熱可塑性樹脂は、ガラス転移温度（Ｔｇ（℃））が、４０〜１５０℃であることが好ましく、より好ましくは５０〜１３０℃、特に好ましくは６０〜１２０℃である。前記熱可塑性樹脂のガラス転移温度（Ｔｇ（℃））が、上記範囲である場合、液晶表示板を組み立てる際には短時間の加熱・加圧であっても電極基板に強く固着させることができるので好ましいが、１５０℃を超える場合は、加熱・加圧時に、熱可塑性樹脂微粒子が溶融しにくく、そのため電極基板との接着性が不十分となるおそれがあるので好ましくなく、また、４０℃未満では、スペーサーに用いた場合に貯蔵中に粒子どうしで融着を起こしたり、電極基板上へ散布時の分散性が悪くなるおそれがあるので好ましくない。
【００３０】
前記熱可塑性樹脂の融解開始温度は、好ましくは５０〜１６０℃、より好ましくは６０〜１５０℃、さらに好ましくは７０〜１４０℃である。融解開始温度が５０℃未満では、スペーサーに用いた場合に貯蔵中に融着等を起こしたり、電極基板上に散布する際の分散性が悪くなるおそれがあるので好ましくなく、一方、融解開始温度が１６０℃を超えると、液晶表示板を組み立てる際の加熱加圧時に、熱可塑性樹脂が溶融しにくく、そのため電極基板との接着性が不充分となるおそれがあるので好ましくない。
本発明における熱可塑性樹脂微粒子は、染料および顔料からなる群から選ばれる少なくとも１つを含むことで着色されていてもよく、特に限定はされないが、たとえば、スペーサーの原料粒子の着色に使用できる染料および顔料として前述したもの等を好ましく挙げることができる。またその色は、光が透過しにくいか、または、透過しない色が、光抜けを防止でき画質のコントラストを向上できる点で好ましい。光が透過しにくい、または、透過しない色としては、例えば、黒、濃青、紺、紫、青、濃緑、緑、茶、赤等の色が挙げられるが、特に好ましくは、黒、濃青、紺色である。
【００３１】
本発明における熱可塑性樹脂微粒子の平均粒子径については、特に限定されるわけではないが、２μｍ以下であることが好ましく、より好ましくは１μｍ以下、最も好ましくは０．７μｍ以下である。前記熱可塑性樹脂微粒子の平均粒子径が２μｍを超えると、スペーサーにおける前記原料粒子を被覆するのが困難になるおそれがあるので好ましくない。なお、この熱可塑性樹脂微粒子の平均粒子径の測定方法も、前記原料粒子の平均粒子径の測定と同様の方法を採用することが好ましい。
本発明の接着性スペーサーにおける熱可塑性樹脂微粒子からなる前記接着層の厚みは、特に限定されるわけではないが、通常、０．０１〜２μｍが好ましく、より好ましくは０．０５〜１μｍである。この厚みが上記範囲より小さい場合、接着性が低下するおそれがあり、また、厚みが上記範囲より大きい場合、配向膜やカラーフィルター等を覆う面積が広くなって、液晶表示板の表示品位が低下するおそれがあるので好ましくない。
【００３２】
本発明における熱可塑性樹脂微粒子は、例えば、水相中において、水相のｐＨを調整した場合に所望の電荷符号および所望の電荷量にするために、イオン性界面活性剤での後処理により分散させたもの、および／または、イオン性の単量体、重合開始剤および乳化剤の群から選ばれる少なくとも１種を含む原料から合成したものを使用することが好ましい。
前記イオン性の単量体、重合開始剤および乳化剤としては、特に限定されるわけではないが、アニオン性またはカチオン性の単量体、重合開始剤および乳化剤の群から選ばれる少なくとも１種のイオン性の原料であることが好ましく、熱可塑性樹脂微粒子を合成するための原料中に、０．００１〜１００ｗｔ％含まれることが好ましく、より好ましくは０．０１〜７０ｗｔ％、さらに好ましくは０．１〜２５ｗｔ％である。０．００１ｗｔ％未満の場合は、イオン性が低くヘテロ凝集が困難となるため好ましくない。
【００３３】
前記アニオン性の単量体、重合開始剤および乳化剤としては、特に限定されるわけではないが、カルボキシル基あるいはスルホン基を有するモノマー、ラジカル重合開始剤および界面活性剤等を好ましく挙げることができ、代表的なモノマーとしては、アクリル酸、（メタ）アクリル酸、マレイン酸およびスルホスチレン等を好ましく挙げることができる。
前記カチオン性の単量体、重合開始剤および乳化剤としては、特に限定されるわけではないが、アミノ基、アミド基、第四級アンモニウム塩基等を好ましく挙げることができ、具体的には、Ｎ，Ｎ−ジメチルアミノエチルメタクリレート、Ｎ，Ｎ−ジエチルアミノエチルメタクリレート、Ｎ−メチルアミノエチルメタクリレート、Ｎ，Ｎ−ジメチルアミノメチルメタクリレート、ｐ−Ｎ，Ｎ−ジメチルアミノフェニルメタクリレート、Ｎ，Ｎ−ジメチルアミノエチルアクリレート、Ｎ，Ｎ−ジエチルアミノエチルアクリレート、Ｎ−メチルアミノエチルアクリレート、Ｎ，Ｎ−ジエチルアミノメチルアクリレート、ｐ−Ｎ，Ｎ−ジメチルアミノフェニルアクリレート；Ｎ，Ｎ−ジメチルアミノエチルメタクリルアミド、Ｎ，Ｎ−ジエチルアミノエチルメタクリルアミド、Ｎ−メチルアミノエチルメタクリルアミド、Ｎ，Ｎ−ジメチルアミノメチルメタクリルアミド、ｐ−Ｎ，Ｎ−ジメチルアミノフェニルメタクリルアミド、Ｎ，Ｎ−ジメチルアミノエチルアクリルアミド、Ｎ，Ｎ−ジエチルアミノエチルアクリルアミド、Ｎ−メチルアミノエチルアクリルアミド、Ｎ，Ｎ−ジエチルアミノメチルアクリルアミド、ｐ−Ｎ，Ｎ−ジメチルアミノフェニルアクリルアミド；Ｎ，Ｎ−ジメチルメタクリルアミド、Ｎ，Ｎ−ジエチルメタクリルアミド、Ｎ−プロピルメタクリルアミド、Ｎ，Ｎ−ジメチルアクリルアミド、Ｎ，Ｎ−ジエチルアクリルアミド、Ｎ−プロピルアクリルアミド；ｐ−Ｎ，Ｎ−ジメチルアミノスチレン、ｐ−Ｎ，Ｎ−ジエチルアミノスチレン、ｐ−Ｎ，Ｎ−ジプロピルアミノスチレン、ｐ−Ｎ，Ｎ−メチルアミノスチレン；Ｎ−ビニルジメチルアミン、Ｎ−ビニルジエチルアミン、Ｎ−ビニルジプロピルアミン、Ｎ−ビニルプロピルアミン；各々メタまたはパラ位にアミノ基が付いたビニルベンジルアルキルアミン（アルキル基は、炭素数１〜２２の置換または未置換アルキル基）、ビニルフェネチルジアルキルアミン（アルキル基は、炭素数１〜２２の置換または未置換アルキル基）；４−ビニルピリジン、２−ビニルピリジン、Ｎ−ビニルイミダゾール；イソプロペニルオキサゾリン等を好ましく挙げることができる。
【００３４】
さらに、上記化合物に対し、第四級アンモニウム塩の形にしたものも好ましく用いることができる。例えば、炭素数１〜２２のアルキル基、ベンジル基、シクロアルキル基等を有しているものが好ましい。
また、前記イオン性の乳化剤（イオン性の界面活性剤）および前記イオン性の単量体は、両性界面活性剤および両性単量体であってもよい。
（スペーサー）
本発明にかかる液晶表示板用接着性スペーサーにおいて、その粒子構造は、粒子本体となる原料粒子と、その表面の少なくとも一部に付着した接着層を形成するための熱可塑性樹脂微粒子とを含む構造であることが好ましく、この構造は、粒子本体となる原料粒子と熱可塑性樹脂微粒子とが粒子表面に互いに異なる符合の電荷（ゼータ電位）を有し、その際生じる静電引力によりヘテロ凝集してなる。また、ヘテロ凝集後に、未被覆（未付着）の熱可塑性樹脂微粒子を除去しておくことが、その後の工程において、熱可塑性樹脂微粒子単独の凝集物が存在しないために重要である。さらには、ヘテロ凝集後、原料粒子に付着した熱可塑性樹脂微粒子の少なくとも一部を溶融させてなることが好ましいが、特に限定されるわけではない。ここで、上述の溶融は、衝撃力、特に、高速気流中衝撃法による衝撃力を加えることによってなされる溶融であることが好ましく、熱可塑性樹脂（熱可塑性樹脂微粒子）が原料粒子の表面により強固に付着した接着性スペーサーとなるため好ましい。
【００３５】
本発明にかかる液晶表示板用接着性スペーサーにおいて、原料粒子と熱可塑性樹脂微粒子の重さの割合〔（熱可塑性樹脂微粒子／原料粒子）×１００〕（ｗｔ％）については、特に限定されるわけではないが、０．１〜２５０ｗｔ％であることが好ましく、より好ましくは１〜１５０ｗｔ％、最も好ましくは２〜１００ｗｔ％である。上記熱可塑性樹脂粒子の割合が２５０ｗｔ％を超える場合は、得られる接着性スペーサーの接着層が厚くなりすぎて、溶融した際に電極基板や配向膜やカラーフィルターを覆う面積が大きくなり、液晶表示板の画質低下を招く恐れがあるので好ましくなく、他方、熱可塑性樹脂粉末の割合が０．１ｗｔ％未満の場合は、接着性が低下するおそれがあるので好ましくない。
【００３６】
本発明により得られる液晶表示板用接着性スペーサーの平均粒子径は、特に限定されるわけではないが、この平均粒子径は原料粒子に熱可塑性樹脂微粒子からなる接着層の厚みが付与されたものであり、１μｍ〜３２μｍが好ましく、より好ましくは１μｍ〜２２μｍ、さらに好ましくは１．２μｍ〜１７μｍである。
本発明にかかる液晶表示板用接着性スペーサーを、液晶表示板用の接着性スペーサーとして用いた場合、粒子本体となる原料粒子に未被覆（未付着）の熱可塑性樹脂微粒子どうしの凝集の防止と、未被覆（未付着）の熱可塑性樹脂微粒子の除去をすることができるため、熱可塑性樹脂微粒子単独の凝集物（異物）が無く、また、原料粒子への熱可塑性樹脂微粒子の被覆効率が高いため、電極基板上に効率的に接着・固定され、スペーサー自身の移動の防止と、液晶表示板のコントラストが高くなる等の画質向上を達成することができる。
【００３７】
〔液晶表示板用接着性スペーサーの製造方法〕
本発明にかかる液晶表示板用接着性スペーサーの製造方法としては、粒子本体となる原料粒子と熱可塑性樹脂微粒子とを水相中でヘテロ凝集させる工程と、ヘテロ凝集に関与しなかった前記熱可塑性樹脂微粒子を除去する工程とを含むものであり、これらの工程によって粒子本体となる前記原料粒子の表面の少なくとも一部を前記熱可塑性樹脂微粒子からなる接着層で被覆させることが好ましい。
一般的に、ヘテロ凝集とは、粒子径および電荷の符号が異なる２種類の球状粒子を混合すると、両粒子間の凝集が優先して起こり、一方が他方によって取り囲まれた複合凝集体が形成されることをいい、通常、小さい方の粒子によって大きい方の粒子を取り囲むようにする場合が多いが、両粒子の粒子数比の範囲を広くとる場合、大きい方の粒子によって小さい方の粒子を取り囲むようにすることも可能である。
【００３８】
本発明の液晶表示板用接着性スペーサーの製造方法におけるヘテロ凝集を含む工程については、上記「粒子径および電荷の符号が異なる２種類の球状粒子」が、原料粒子と熱可塑性樹脂微粒子であり、両粒子間の静電引力によるヘテロ凝集によって、原料粒子が熱可塑性樹脂微粒子に取り囲まれるように被覆されることが好ましく、この場合、前記原料粒子および前記熱可塑性樹脂微粒子は、粒子そのものであってもよいし、粒子をイオン性の処理剤などで何らかの処理をされたものであってもよい。
詳しくは、たとえば、水相をｐＨ調整した場合、イオン性界面活性剤（ａ）を用いて分散させた原料粒子（Ａ１）と、このイオン性界面活性剤（ａ）と反対の電荷を有するイオン性界面活性剤（ｂ）で分散させた熱可塑性樹脂微粒子（Ｂ１）あるいはこのイオン性界面活性剤と反対の電荷を有するイオン性単量体を必須とする単量体成分から合成されたもので好ましくはこのイオン性単量体由来の官能基・電荷を粒子表面に有する前記熱可塑性樹脂微粒子（Ｂ２）の少なくとも一方とが混合した水相では、両粒子間の静電的相互作用により生じる静電引力によって両粒子間にヘテロ凝集が生じ、前期原料粒子の表面の少なくとも一部が前記熱可塑性樹脂微粒子に取り囲まれるように被覆される。
【００３９】
本発明にかかる液晶表示板用接着性スペーサーの製造方法においては、熱可塑性樹脂微粒子と原料粒子との平均粒子径の比（熱可塑性樹脂微粒子／原料粒子）は、１／１００００〜２／５を採用することが好ましく、より好ましくは１／１０００〜３／１０、さらに好ましくは１／１００〜１／５である。前記平均粒子径の比が、上記範囲外となる場合は、熱可塑性樹脂微粒子によって原料粒子を被覆するのが困難になるおそれがあるので好ましくない。
本発明にかかる液晶表示板用接着性スペーサーの製造方法においては、熱可塑性樹脂微粒子と原料粒子のゼータ電位は互いに異符号となるようにすることが好ましく、両粒子間のゼータ電位の差は、２〜３００ｍＶにすることが好ましく、より好ましくは１０〜１５０ｍＶである。前記ゼータ電位の差が３００ｍＶを超える場合は、系が安定でヘテロ凝集が起こらないため好ましくなく、２ｍＶ未満の場合は、ヘテロ凝集が生じてもスペーサー粒子が単分散で得られないため好ましくない。
【００４０】
本発明にかかる液晶表示板用接着性スペーサーの製造方法において、上記ゼータ電位の条件および数値範囲に関しては、これらを満たすように水相の（分散液の）ｐＨを調整することで達成するのが好ましく、用いる熱可塑性樹脂微粒子と原料粒子とは、ヘテロ凝集時に異符号の電荷を有していることが好ましい。また、前記原料粒子に関しては、原料粒子を水相中に分散させるために用いるイオン性異面活性剤について、一方、前記熱可塑性樹脂微粒子に関しては、熱可塑性樹脂微粒子を分散させるイオン性界面活性剤および／またはこの粒子表面に官能基を導入するためのイオン性の単量体や重合開始剤について、適宜最適なものを選択し、水相のｐＨ調整後に各粒子ともに所望の電荷符号およびゼータ電位となるようにすることが好ましい。このイオン性の単量体や重合開始剤としては、熱可塑性樹脂微粒子の合成に用いるイオン性の単量体や重合開始剤として前述したものが好ましい。
【００４１】
本発明にかかる液晶表示板用接着性スペーサーの製造方法において、原料粒子（この分散液も含む）と熱可塑性樹脂微粒子（この分散液も含む）との水相での混合は、前者に後者を加えても、その逆でもあるいは同時でもよい。また、前記水相のｐＨ調整については、両者の混合前あるいは混合後のいずれで行ってもよい。
本発明にかかる液晶表示板用接着性スペーサーの製造方法においては、水相中にさらに電解質を添加するという工程を含む場合、熱可塑性樹脂微粒子を原料粒子により強固に付着させ被覆させることができる。
【００４２】
前記電解質としては、１価、２価、３価の金属の塩が好ましく用いられるが、より好ましくは１価の金属の塩であり、特に限定されるわけではないが、具体的には、塩化カリウム、塩化ナトリウム、塩化リチウム、硫酸カリウム、硫酸ナトリウム、硫酸リチウム等を好ましく挙げることができる。また、前記電解質の添加量としては、特に限定されるわけではなく任意であるが、１ｍｏｌ／Ｌ以下が好ましく、より好ましくは１×１０^-5〜１×１０^-1ｍｏｌ／Ｌである。ただし、上記のような金属塩を用いた場合、液晶表示板内ではイオン性の不純物として液晶の配向などに悪影響を与えるため、スペーサー粒子の洗浄過程で除去することが好ましい。
【００４３】
本発明にかかる液晶表示板用接着性スペーサーの製造方法においては、上記へテロ凝集をさせる工程において、ヘテロ凝集中および／または凝集後、室温（約２０℃）以上、（Ｔｇ＋５０℃）以下で加熱することが好ましい（ここで、Ｔｇは、本発明における熱可塑性樹脂微粒子に用いる熱可塑性樹脂のガラス転移温度（Ｔｇ（℃））である）。この理由としては、原料粒子と熱可塑性樹脂微粒子との親和力を高めるためであり、特に、前記Ｔｇ（℃）以上の加熱をした場合は、熱可塑性樹脂微粒子はその少なくとも一部が溶融して原料粒子表面に強固に付着するため、本発明の接着性スペーサーを単離する際に、熱可塑性樹脂微粒子の剥離を低減することができる。
【００４４】
本発明にかかる液晶表示板用接着性スペーサーの製造方法においては、上記ヘテロ凝集させる工程の後、さらに、水相中の未被覆（未付着）の残余熱可塑性樹脂微粒子を除去する工程を含むことが好ましい。本発明においては、用いる熱可塑性樹脂微粒子はすべて同符号の電荷を好ましく有するので、未被覆のものとして水相中に遊離している場合、静電気的効果により互いに反発し合うため、前記原料粒子の表面に付着し接着性スペーサーとなった粒子と未被覆の粒子との粒子径は明確に区別できる。
本発明にかかる液晶表示板用接着性スペーサーの製造方法においては、水相中の未被覆の残余熱可塑性樹脂微粒子の除去には電成ふるいを備えた分級装置を用いることが好ましい。
【００４５】
前記電成ふるいとは、メッキによって矩形の孔を有するスクリーンを作製したものである。電成ふるいの製造方法としては、高精度にクロスライン状に腐食させたガラス原板上に、真空蒸着、スパッタリング等の物理メッキ、あるいは電解メッキ、無電解メッキ等の化学メッキにより導電性被膜を形成した後、腐食部分の溝以外のメッキ層を除去し、これに電解メッキ等の方法でメッシュを形成し、ガラス原板から剥離する方法が挙げられる。このようにして作製されたメッシュはガラス原板から剥離後、必要に応じてさらに電解メッキを施してもかまわない。また、他の製造方法として、ガラス平板上に真空蒸着、スパッタリング等の物理メッキ、あるいは電解メッキ、無電解メッキ等の化学メッキにより導電性被膜を形成し、その被膜上にレジストを塗布した後、所定の形状のパターンを形成し、その後エッチングによりパターン以外の部分を除去し、ガラス原板から剥離後、電解メッキを施す方法も挙げられる。
【００４６】
前記電成ふるいの材質としては、金、白金、銀、銅、鉄、アルミニウム、ニッケル及びこれらをベースとする種々の合金が用いられるが、ふるいの耐久性、耐蝕性やメッキ作業の容易さからニッケルを主成分とするものが特に好ましく用いられる。
前記電成ふるいは、開孔径、単位あたりの開孔数の調整が容易であるばかりでなく、開孔径分布が非常に良好であるため、ふるいとして用いた場合、非常に精度良く分級することが可能となる。
前記電成ふるいは非常に薄いため簡単に傷ついたり、破れたりし、分級された粒子へ金属系不純物の混入のおそれがある。特に分級された粒子を本発明の液晶表示板用接着性スペーサー等の電子材料の用途に用いる場合、金属系不純物の混入は品質および信頼性の低下の原因となるため重大な問題である。そのため、電成ふるいの片面あるいは両面に格子状あるいはリング状等のサポートを設けて強度を上げることが好ましい。
【００４７】
前記電成ふるいの分級装置への取り付けに関しては、特に超音波振動を印加する場合など、電成ふるいと分級装置とが擦れて電成ふるいが破損し分級された粒子へ金属系不純物が混入するおそれがあるため、エラストマーからなる部材を介して取り付けることが好ましい。
前記電成ふるいを用いた分級工程においては、粒子の分散液を電成ふるいを備えた分級装置に通すことによって湿式法により分級を行うことが好ましい。媒体として不活性ガスや空気などを用いる乾式法と比較して、湿式法による場合の方が超音波の照射効率、分散の安定性が高く、また電成ふるいへの粒子の付着が少ない。特に液晶表示板用の接着性スペーサーなどに用いる粒子径の小さいものは凝集力が強いため、乾式法では分散が不十分になる場合がある。前記湿式法において、粒子を分散させる液状媒体としては、用いる電成ふるいの材質、開孔径、線数および粒子の性状あるいは粒子径分布などによって適切に選択することができる。また、分級に際しては、分級装置内に超音波照射チップを挿入した場合、水等の液状媒体に超音波照射を行うことで、分級の効率を好ましく向上させることができる。
【００４８】
本発明にかかる液晶表示板用接着性スペーサーの製造方法においては、原料粒子と熱可塑性樹脂微粒子とをヘテロ凝集させ、残余熱可塑性樹脂微粒子を除去した後、さらに、前記熱可塑性樹脂微粒子の少なくとも一部を溶融する溶融工程を含むことが好ましいが、特に限定されるわけではない。溶融する方法としては、ガラス転移温度Ｔｇ（℃）から（Ｔｇ＋５０℃）の温度範囲で加熱処理をする、および、衝撃力を加える等の方法を好ましく挙げることができ、衝撃力を加える方法がより好ましく、なかでも、高速気流中衝撃法により衝撃力を加える方法が特に好ましい。前記高速気流中衝撃法を採用するにあたっては、特に限定されるわけではないが、奈良機械製作所製「ハイブリダイゼーションシステム」、ホソカワミクロン株式会社製「メカノフージョンシステム」、および、川崎重工株式会社製「クリプトロンシステム」等を用いることが好ましく、なかでも、奈良機械製作所製「ハイブリダイゼーションシステム」が特に好ましい。このような高速気流中衝撃法による処理によって熱可塑性樹脂（熱可塑性樹脂微粒子）を原料粒子の表面により強固に付着させることができるので好ましい。
【００４９】
また、本発明にかかる液晶表示板用接着性スペーサーの製造方法においては、得られた接着性スペーサーを精製するため、上述した「残余熱可塑性樹脂微粒子を除去する工程」と同じ方法で分級精製してもよい。
【００５０】
【実施例】
以下に、実施例により、本発明をさらに具体的に説明するが、本発明はこれらにより何ら限定されるものではない。なお、以下では、便宜上、「重量部」を単に「部」と記すことがある。
まず、以下の製造例１〜５により、実施例および比較例に用いる各種粒子成分を合成する。また、これら製造例１〜５の記載中に示す、各種粒子の平均粒子径（および粒子径の標準偏差、粒子径の変動係数）は下記の方法により測定した。
〔平均粒子径と粒子径の変動係数〕
試料を電子顕微鏡により観察して、その撮影像の任意の試料２００個の粒子径を実測し、次式に従って、平均粒子径、粒子径の標準偏差および粒子径の変動係数を求めた。
【００５１】
【数１】

【００５２】
【数２】

【００５３】
【数３】

【００５４】
−製造例１−
（有機質無機質複合体粒子）
γ−メタクリロキシプロピルトリメトキシシランおよびビニルトリメトキシシラン（４５／５５重量比）を使用して、アルコキシシリル基の共加水分解・重縮合と、二重結合のラジカル重合を行うことにより、白色の有機質無機質複合体粒子を得て、これを原料粒子（Ａ）とした。
原料粒子（Ａ）の粒子径を電子顕微鏡により観察し、粒子径を測定したところ、平均粒子径５．５μｍ、粒子径変動係数２．９％であり、ポリシロキサン骨格の割合は、原料粒子（Ａ）の重量に対して、ＳｉＯ₂換算量で５４ｗｔ％（空気中１０００℃で焼成した場合）であった。
【００５５】
−製造例２−
（アミノ基含有熱可塑性樹脂微粒子分散液）
撹拌機、還流冷却器、窒素導入管および温度計を備えたフラスコに、脱イオン水７８２．４部およびハイテノールＮ−０８（第一工業製薬株式会社製、ポリオキシエチレンノニルフェニルエーテル硫酸アンモニウム塩）の１５％水溶液１２８部を仕込み、緩やかに窒素ガスを流しながら７０℃に加熱した。そこへ、過硫酸カリウムの５％水溶液を６４部注入し、予め調製しておいたアクリル酸ブチル２８８部、スチレン２８８部およびジメチルアミノエチルメタクリレート６４部からなる単量体混合物を３時間にわたって滴下した。反応中は窒素ガスを流し続け、フラスコ内の温度を７０±１℃に保った。滴下終了後も２時間同じ温度に保った後、内温を８０℃に昇温させて１時間撹拌を続けて反応を完結させた。その後、冷却し、不揮発分３９．８ｗｔ％、ｐＨ８．０のアミノ基含有熱可塑性樹脂微粒子分散液（Ｂ）を得た。また、得られた熱可塑性樹脂微粒子分散液（Ｂ）の粒子径をＤＬＳ７００（大塚電子株式会社製）およびゼータ電位をＥＬＳ−８００（大塚電子株式会社製）を用いて測定したところ、平均粒子径は８５ｎｍ、ゼータ電位は＋５３ｍＶ（ｐＨ８．０）であった。
【００５６】
−製造例３−
（カルボキシル基含有熱可塑性樹脂微粒子）
撹拌機、還流冷却器、窒素導入管および温度計を備えたフラスコに、脱イオン水６４０部およびハイテノールＮ−０８（第一工業製薬株式会社製、ポリオキシエチレンノニルフェニルエーテル硫酸アンモニウム塩）の１５％水溶液１２８部を仕込み、緩やかに窒素ガスを流しながら７０℃に加熱した。そこへ、過硫酸カリウムの５％水溶液を６４部注入し、予め調製しておいたアクリル酸ブチル３２０部、メタクリル酸メチル２９４．４部、およびアクリル酸２５．６部からなる単量体混合物を３時間にわたって滴下した。反応中は窒素ガスを流し続け、フラスコ内の温度を７０±１℃に保った。滴下終了後も２時間同じ温度に保った後、内温を８０℃に昇温させて１時間撹拌を続けて反応を完結させた。その後、冷却し、不揮発分４５．１ｗｔ％、ｐＨ２．３のカルボキシル基含有熱可塑性樹脂微粒子分散液（Ｃ）を得た。また、得られた熱可塑性樹脂微粒子分散液（Ｃ）の粒子径をＤＬＳ７００（大塚電子株式会社製）およびゼータ電位をＥＬＳ−８００（大塚電子株式会社製）を用いて測定したところ、平均粒子径は１０３ｎｍ、ゼータ電位は−４１ｍＶ（ｐＨ２．３）であった。
【００５７】
−製造例４−
（オキサゾリン基含有熱可塑性樹脂微粒子）
撹拌機、還流冷却器、窒素導入管および温度計を備えたフラスコに、脱イオン水７８２．４部およびハイテノールＮ−０８（第一工業製薬株式会社製、ポリオキシエチレンノニルフェニルエーテル硫酸アンモニウム塩）の１５％水溶液１２８部を仕込み、緩やかに窒素ガスを流しながら７０℃に加熱した。そこへ、過硫酸カリウムの５％水溶液を６４部注入し、予め調製しておいたアクリル酸ブチル２８８部、スチレン２８８部および２−イソプロペニル−２−オキサゾリン６４部からなる単量体混合物を３時間にわたって滴下した。反応中は窒素ガスを流し続け、フラスコ内の温度を７０±１℃に保った。滴下終了後も２時間同じ温度に保った後、内温を８０℃に昇温させて１時間撹拌を続けて反応を完結させた。その後、冷却し、不揮発分３９．８ｗｔ％、ｐＨ８．０のオキサゾリン基含有熱可塑性樹脂微粒子分散液分散液（Ｄ）を得た。また、得られた熱可塑性樹脂微粒子分散液（Ｄ）の粒子径をＤＬＳ７００（大塚電子株式会社製）およびゼータ電位をＥＬＳ−８００（大塚電子株式会社製）を用いて測定したところ、平均粒子径は８５ｎｍ、ゼータ電位は＋５３ｍＶ（ｐＨ８．０）であった。
【００５８】
−製造例５−
（アニオン性熱可塑性樹脂微粒子分散液）
撹拌機、還流冷却器、窒素導入管および温度計を備えたフラスコに、脱イオン水５７６部を仕込み、緩やかに窒素ガスを流しながら７０℃に加熱した。そこへ、過硫酸カリウムの２０％水溶液を６４部注入し、予め調製しておいたアクリル酸ブチル８０部、メタクリル酸メチル７５部およびアクリル酸５部からなる単量体混合物を２時間にわたって滴下した。反応中は窒素ガスを流し続け、フラスコ内の温度を７０±１℃に保った。滴下終了後も２時間同じ温度に保った後、内温を８０℃に昇温させて１時間撹拌を続けて反応を完結させた。その後、冷却し、不揮発分１９．８ｗｔ％、ｐＨ２．３のアニオン性の熱可塑性樹脂微粒子分散液分散液（Ｅ）を得た。また、得られた熱可塑性樹脂微粒子分散液（Ｅ）の粒子径をＤＬＳ７００（大塚電子株式会社製）およびゼータ電位をＥＬＳ−８００（大塚電子株式会社製）を用いて測定したところ、平均粒子径は４５０ｎｍ、ゼータ電位は−５６ｍＶ（ｐＨ２．３）であった。
【００５９】
−実施例１−
原料粒子（Ａ）５０部を水１５０部に超音波分散させた際のｐＨは４．０であり、ゼータ電位は−２０ｍＶであった。この原料粒子分散液２００部にカチオン性の熱可塑性樹脂微粒子分散液（Ｂ）２００部を添加した。その混合液のｐＨは７．０、ゼータ電位は＋２３ｍＶであった。この混合分散液を、撹拌機、還流冷却器、窒素導入管および温度計を備えたフラスコに仕込み、緩やかに窒素ガスを流しながら、７０℃にて２時間加熱した。得られた分散混合液を光学顕微鏡で観察したところ、系の凝集ならびに熱可塑性樹脂微粒子からなる原料粒子程度の凝集物は観察されず、熱可塑性樹脂微粒子の単体、および原料粒子が熱可塑性樹脂微粒子に被覆されてなる接着性スペーサー（１）のみが観察された。
【００６０】
分級工程においては、まず、細孔径１ミクロンのメンブランフィルターを利用して、上記工程で得た分散混合液の濾過を行った。フィルターを透過した濾過後の液には、熱可塑性樹脂微粒子のみが存在した。この濾過によってフィルター側に残存した接着性スペーサー（１）を、分散媒としてメタノールを用いて再度分散させ、電成ふるいを備えた分級装置によって分級した。分級装置内の粒子濃度は５〜２０ｗｔ％を保つよう適宜メタノールの補給を行った。
分級するに際し、電成ふるいとしてニッケル系で開孔径２．０μｍのものを用いて分級を行ったあと、ふるい上部に残存した液を回収し、さらに、これをニッケル系で開孔径１０．０μｍのものを用いて再び分級を行い、ふるい下部に流出した、分級後の接着性スペーサー（１）の分散液を回収した。
【００６１】
−実施例２−
原料粒子（Ａ）１００部をメタノール５００部および水２０ｇに超音波分散させた系に、カチオン性のシランカップリング剤（信越シリコーン製、品名：Ｘ−１２−６１４）２０部、触媒としてイオン交換樹脂１ｇを加えて、６０℃メタノール還流下で２時間反応を行った。反応後のカチオン性の原料粒子をメタノールでよく洗浄した後、１００℃の減圧乾燥器で一晩乾燥させた。
カチオン性の原料粒子５０部を水１５０部に超音波分散させた際のｐＨは８．８であり、ゼータ電位は＋２６ｍＶであった。この原料粒子分散液２００部にアニオン性の熱可塑性樹脂微粒子分散液（Ｃ）２００部を添加した。その混合液のｐＨは６．５、ゼータ電位は−１６ｍＶであった。この混合分散液を、撹拌機、還流冷却器、窒素導入管および温度計を備えたフラスコに仕込み、緩やかに窒素ガスを流しながら、７０℃にて２時間加熱した。得られた分散混合液を光学顕微鏡で観察したところ、系の凝集ならびに熱可塑性樹脂微粒子からなる原料粒子程度の凝集物は観察されず、熱可塑性樹脂微粒子の単体、および原料粒子が熱可塑性樹脂微粒子に被覆されてなる接着性スペーサー（２）のみが観察された。
【００６２】
分級工程においては実施例１と同様の方法により、濾過、懸濁および分級を行い、分級後の接着性スペーサー（２）の分散液を回収した。
−実施例３−
原料粒子（Ａ）１００部をメタノール５００部および水２０ｇに超音波分散させた系に、カチオン性のシランカップリング剤（信越シリコーン製、品名：Ｘ−１２−６１４）２０部、触媒としてイオン交換樹脂１ｇを加えて、６０℃メタノール還流下で２時間反応を行った。反応後のカチオン性の原料粒子をメタノールでよく洗浄した後、１００℃の減圧乾燥器で一晩乾燥させた。
【００６３】
カチオン性の原料粒子１００部をｐＨ３に調製した酢酸水溶液３００部に分散させ、アニオン性の熱可塑性樹脂微粒子分散液分散液（Ｅ）１００部と混合し、ヘテロ凝集を行った。この得られたヘテロ凝集分散液を細孔径１μｍのメンブランフィルターを利用して濾過により分別した。その後、濾別粒子を４０℃の減圧乾燥下で一晩乾燥させた。乾燥した粒子３６部を、奈良機械製作所製ハイブリダイゼーションシステムＮＨＳ−０型を用いた高速気流中衝撃法により衝撃力を加えて、熱可塑性樹脂微粒子からなる接着層を溶融させ、均一被覆を行い、実施例３の接着性スペーサー（３）を得た。
【００６４】
分級工程においては実施例１と同様の方法により、濾過、懸濁および分級を行い、分級後の接着性スペーサー（３）の分散液を回収した。
−実施例４−
実施例１において用いたカチオン性の熱可塑性樹脂微粒子分散液（Ｂ）の代わりに、製造例４のオキサゾリン基含有熱可塑性樹脂微粒子分散液分散液（Ｄ）を用いた以外は、実施例１と同様にして、実施例４の接着性スペーサー（４）を得た。
分級工程においても実施例１と同様の方法により、濾過、懸濁および分級を行い、分級後の接着性スペーサー（４）の分散液を回収した。
【００６５】
−比較例１−
原料粒子（Ａ）３０ｇと、製造例３で合成した熱可塑性樹脂微粒子分散液（Ｃ）をドライアップして得た熱可塑性樹脂微粒子６ｇとを混合した後、奈良機械製作所（株）製、ハイブリダイゼーションシステムＮＨＳ−０型を使用し、高速気流中衝撃法により、原料粒子の表面を熱可塑性樹脂微粒子で被覆処理することにより、比較例１の接着スペーサー（比較接着性スペーサー（１））を得た。
分級工程においては、実施例１の濾過工程を除いた工程と同様に、比較接着性スペーサー（１）を分散媒としてメタノールを用いて再度分散させ、電成ふるいを用いて行い、分級後の比較接着性スペーサー（１）の分散液を回収した。
上記実施例１〜４および比較例１より得られた接着性スペーサー（１）〜（４）および比較接着性スペーサー（１）について、固着力試験および樹脂異物評価を行った。
【００６６】
（固着力試験）
加熱処理後の接着性スペーサーの基板への固着力（接着力）を、エアブロー法によりエアブロー前後の粒子残存率を計算し、評価した。その結果を表１に示す。残存率は３回測定後の平均値である。
基板：スライドガラス
加熱：ホットプレートにより、１５０℃あるいは１８０℃で１０分間加熱した。
エアブロー法：スライドガラスに直角にエアーガンをセットし、圧力２ｋｇ／ｃｍ²にて１０秒エアブローをした。
【００６７】
粒子数：測定した粒子数は５０００個である。
【００６８】
【表１】

【００６９】
（樹脂異物評価）
濾別・乾燥したサンプルをＳＥＭ（日立製：Ｓ３５００）にて任意の５視野（倍率：１０００倍、粒子総数：約５０００）を観察し、熱可塑性樹脂微粒子単体等が凝集した接着性スペーサー以外の樹脂異物の個数を計測した。
【００７０】
【表２】

【００７１】
【発明の効果】
本発明によれば、熱可塑性樹脂微粒子どうしの付着および凝集を防止し、スペーサー粒子本体となる原料粒子表面への熱可塑性樹脂微粒子の被覆効率を高め、未被覆（非付着）の熱可塑性樹脂微粒子の除去が容易に可能で、液晶表示板用の接着性スペーサーとして用いた場合に良好な分散性が得られる、新規な液晶表示板用接着性スペーサーおよびその製造方法を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention has a high encapsulation efficiency of the adhesive layer was reduced and image quality deterioration of the liquid crystal display panel with an adhesive layer alone aggregate, a method of manufacturing a liquid crystal display panel for adhesive spacers over.
[0002]
[Prior art]
Conventionally, a liquid crystal display (LCD) has been widely used as an image display element for televisions, personal computers, word processors, PHS (personal digital assistants), car navigation systems, and the like. In particular, a liquid crystal display panel called TFT-LCD can respond to high-speed response and wide viewing angle. Therefore, the development of large-screen TFT-LCD of 13 inches or more has been developed for the purpose of replacing the cathode ray tube (CRT). Has been studied.
However, especially when manufacturing large-screen TFT-LCDs, vibrations and shocks are applied during the manufacturing process of the liquid crystal panel, that is, when the substrate is transported, when the substrate is cut, and when the liquid crystal panel is transported. 1) Increased light leakage and decreased contrast due to disordered alignment of the liquid crystal and damage to the alignment film, and 2) problems of causing deterioration in the quality of the liquid crystal panel such as gap unevenness and color unevenness. Therefore, for the purpose of preventing the spacer from moving and falling off, an adhesive spacer having a spacer particle surface coated with an adhesive layer made of a thermoplastic resin has been developed and studied.
[0003]
In particular, in the step of covering the adhesive layer in the adhesive spacer, impact (friction) force (for example, high-speed in-air impact method using a hybridization system manufactured by Nara Machinery Co., Ltd., etc.) In which the surface of the particle body is coated with a thermoplastic resin (Japanese Patent Laid-Open Nos. 63-94224, 1-154028, 8-328822, and 9-235527). No.) is often adopted.
However, with the conventional methods and techniques alone, among the thermoplastic resins used to coat the particle body, many of the thermoplastic resins remain uncoated and are coated by coalescence or aggregation of thermoplastic resin powders. Even after the process, an uncoated resin alone is often present as a foreign substance, and some having a particle size similar to that of the generated spacer may be produced as a by-product as a foreign substance. These foreign substances are very difficult to remove and purify, and when they are sprayed on the electrode substrate together with the spacers, they melt during heating and pressurization and cover the alignment film in the pixel over a wide area. There is a problem that the liquid crystal display panel with low display quality can be obtained because the light from the backlight is not transmitted and the light is transmitted, the contrast is lowered. In addition, in relation to the above problems, the coating efficiency of the thermoplastic resin used is still very low at the present time, so in order to obtain a sufficient adhesive layer thickness, the amount of thermoplastic resin used must be increased. Further, there is a problem that foreign matter increases, and the current level is not sufficient, and further improvement is desired.
[0004]
[Problems to be solved by the invention]
Therefore, the problem to be solved by the present invention, is possible to prevent sticking and aggregation of to it etc. thermoplastic resin fine particles, increase the coating efficiency to particle body, to easily remove the thermoplastic resin fine particles uncoated possible, good dispersibility is obtained when used as a spacer for a liquid crystal display panel, it is to provide a novel process for producing liquid crystal display panel for adhesive spacers over.
[0005]
[Means for Solving the Problems]
The present inventor has intensively studied to solve the above problems. As a result, attention was focused on heteroaggregation of the particle body and the thermoplastic resin fine particles, removal of the thermoplastic resin fine particles not involved in the heteroaggregation, and the like. For a new liquid crystal display panel, an ideal ordered mixture is completed between the particle body and the thermoplastic resin particles, and the thermoplastic resin particles are adhered to at least a part of the surface of the particle body by heteroaggregation. production method of the adhesive spacers over of found that can solve the above problems and completed the present invention.
[0006]
That is, a method of manufacturing a liquid crystal display panel for adhesive spacers over according to the present invention, a method of obtaining a bonding spacer of a liquid crystal panel for at least a portion of the surface of the particle body is coated with an adhesive layer comprising a thermoplastic resin Wherein the raw material particles as the particle body and the thermoplastic resin fine particles as the adhesive layer are heteroaggregated by having opposite ionic charges in the aqueous phase; And a step of removing the thermoplastic resin fine particles.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the adhesive spacer for a liquid crystal display panel of the present invention and the manufacturing method thereof will be described in detail.
[Adhesive spacer for LCD panel]
As for the adhesive spacer for liquid crystal display panel according to the present invention, the particle structure preferably includes raw material particles serving as spacer particle bodies and thermoplastic resin fine particles attached to at least a part of the surface thereof. .
Hereinafter, the particle main body (raw material particles), the thermoplastic resin fine particles, and the spacer will be described in detail.
[0008]
(Particle body (raw material particles))
The raw material particles used in the present invention, for example, determine the gap distance between the two electrode plates sandwiching the liquid crystal layer when used for a liquid crystal display plate, and to keep the thickness of the liquid crystal layer uniform and constant. The average particle size is preferably 1 to 30 μm, more preferably 1 to 20 μm, and most preferably 1 to 15 μm. When the average particle diameter of the raw material particles is out of the above range, it is a region that is not normally used as an adhesive spacer for a liquid crystal display panel.
The variation coefficient (CV) of the particle diameter of the raw material particles is preferably 10% or less, more preferably 8% or less, and further preferably 6% or less. When the coefficient of variation of the particle diameter exceeds 10%, when used as an adhesive spacer for a liquid crystal display panel, it becomes difficult to keep the thickness of the liquid crystal layer uniform and constant, which may cause image unevenness. This is not preferable.
[0009]
In addition, it is preferable to employ | adopt the thing as described in the below-mentioned Example as a definition and a measuring method of the said average particle diameter and the variation coefficient of the said particle diameter.
Although it does not necessarily limit as raw material particle | grains, There exist various things, For example, organic crosslinked polymer particle | grains, an inorganic type particle | grain, organic-inorganic composite particle | grains etc. can be mentioned preferably. Among these, the organic cross-linked polymer particles and / or the organic / inorganic composite particles can prevent damage to the electrode substrate, the alignment film, or the color filter, and can easily obtain the uniformity of the gap distance (gap) between the two electrode substrates. Preferably, organic-inorganic composite particles are most preferable.
[0010]
The shape of the raw material particles may be any particle shape such as spherical shape, needle shape, plate shape, scale shape, crushed shape, bowl shape, eyebrow shape, scallop shape, etc., and is not particularly limited. In order to make the gap distance uniform, the spherical shape is preferable. This is because a spherical shape has a constant or substantially constant grain shape in all or almost all directions.
The raw material particles may be preferably colored by containing a dye and / or a pigment.
The organic crosslinked polymer particles are not particularly limited. For example, amino acids obtained by a condensation reaction from at least one amino compound selected from the group consisting of benzoguanamine, melamine and urea and formaldehyde. Cured resin particles (see JP-A-62-268811); divinylbenzene crosslinked resin particles obtained by polymerizing divinylbenzene alone or copolymerizing with other vinyl monomers (see JP-A-1-144429) ) Etc. can be mentioned preferably.
[0011]
Although it does not necessarily limit as said inorganic type particle, For example, spherical fine particles, such as glass, a silica, an alumina, etc. can be mentioned preferably.
The organic inorganic composite particle is preferably a composite particle including an organic part and an inorganic part. In this organic-inorganic composite particle, the proportion of the inorganic part is not particularly limited. For example, the range is 10 to 90 wt% in terms of inorganic oxide with respect to the weight of the organic-inorganic composite particle. More preferably, it is 25-85 wt%, More preferably, it is 30-80 wt%. The inorganic oxide conversion is preferably expressed as a percentage by weight obtained by measuring the weight before and after firing the organic-inorganic composite particles at a high temperature (for example, 1000 ° C.) in an oxidizing atmosphere such as air. If the proportion of the inorganic part of the organic-inorganic composite particle is less than 10 wt% in terms of inorganic oxide, the organic-inorganic composite particle becomes soft and undesirably increases the number of sprayed on the electrode substrate, On the other hand, if it exceeds 90 wt%, it is not preferable because it is too hard to easily cause damage to the alignment film and disconnection of the TFT.
[0012]
Such organic-inorganic composite particles are not particularly limited. For example, organic polymer skeleton and organic silicon in which a silicon atom is directly chemically bonded to at least one carbon atom in the organic polymer skeleton are used. Preferred examples include organic-inorganic composite particles A that contain a polysiloxane skeleton in the molecule and have an amount of SiO ₂ constituting the polysiloxane skeleton of 10 wt% or more. As the organic polymer skeleton, a vinyl-based polymer is preferable because it provides high resilience capable of controlling the gap control. Here, the organic-inorganic composite particle A has a breaking strength satisfying G ≧ 14 · Y ^1.75 (where G represents a breaking strength [kg]; Y represents a particle diameter [mm]). Preferably, the 10% compression elastic modulus is 300 to 2000 kg / mm ² , and the residual displacement after 10% deformation is more preferably 0 to 5%.
[0013]
Although it does not necessarily limit about the manufacturing method of the said organic inorganic composite particle A, For example, the manufacturing method containing the condensation process shown below and a superposition | polymerization process and a heat treatment process can be mentioned preferably.
The condensation step is preferably a step of hydrolysis / condensation using a radical polymerizable group-containing first silicon compound. In this condensation step, a basic catalyst such as ammonia may be preferably used as a catalyst.
The radical polymerizable group-containing first silicon compound has the following general formula (1):
[0014]
[Chemical 1]

[0015]
(Where R ^a represents a hydrogen atom or a methyl group; R ^b represents an optionally substituted divalent organic group having 1 to 20 carbon atoms; R ^c represents a hydrogen atom; R ¹ represents at least one monovalent group selected from the group consisting of an alkyl group having 1 to 5 carbon atoms and an acyl group having 2 to 5 carbon atoms, R ¹ represents an alkyl group having 1 to 5 carbon atoms, a phenyl group, And at least one monovalent group selected from the group consisting of: 1 is 1 or 2, and p is 0 or 1.)
And the following general formula (2):
[0016]
[Chemical 2]

[0017]
(Where R ^d represents a hydrogen atom or a methyl group; R ^e represents at least one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and an acyl group having 2 to 5 carbon atoms. R ² represents at least one monovalent group selected from the group consisting of an alkyl group having 1 to 5 carbon atoms and a phenyl group, m is 1 or 2, and q Is 0 or 1.)
And the following general formula (3):
[0018]
[Chemical 3]

[0019]
(Where R ^f represents a hydrogen atom or a methyl group; R ^g represents an optionally substituted divalent organic group having 1 to 20 carbon atoms; R ^h represents a hydrogen atom; At least one monovalent group selected from the group consisting of an alkyl group having 1 to 5 carbon atoms and an acyl group having 2 to 5 carbon atoms, R ³ represents an alkyl group having 1 to 5 carbon atoms and a phenyl group; And at least one monovalent group selected from the group consisting of: n is 1 or 2, and r is 0 or 1.)
It is preferably a compound represented by at least one general formula selected from the group consisting of or a derivative thereof.
[0020]
The polymerization step is preferably a step in which particles are obtained by radical polymerization reaction of a radical polymerizable group during and / or after the condensation step.
The heat treatment step is a step of drying and firing the polymer particles produced in the polymerization step at a temperature of 800 ° C. or less, more preferably 100 to 600 ° C., for example, in an atmosphere having an oxygen concentration of 10% by volume or less. Or under reduced pressure.
During and / or after at least one step selected from the above condensation step, polymerization step and heat treatment step, it may further comprise a coloring step for coloring the generated raw material particles. It may be colored by containing at least one selected from the group consisting of pigments. The color is preferably a light that does not easily transmit light, or a color that does not transmit light, from the viewpoint that the adhesive spacer itself can prevent light leakage and improve the contrast of image quality. Examples of colors that are difficult to transmit or do not transmit light include black, dark blue, amber, purple, blue, dark green, green, brown, red, and the like, but particularly preferably, Black, dark blue, and scarlet. The dye and / or pigment may be simply contained in the raw material particles, or may have a structure in which the dye and / or pigment and the matrix constituting the raw material particles are combined by chemical bonding. It is not limited to these.
[0021]
The dye is appropriately selected and used according to the color to be colored, and examples thereof include disperse dyes, acid dyes, basic dyes, reactive dyes, sulfur dyes and the like classified according to the dyeing method. Specific examples of these dyes are “Chemical Handbook Applied Chemistry, Japan Chemical Society” (published by Maruzen Co., Ltd., 1986), pages 1399-1427, “Nippon Kayaku Dye Handbook” (1973, published by Nippon Kayaku Co., Ltd.). )It is described in.
As a method of dyeing the raw material particles, a conventionally known method is used. For example, it can be carried out by the methods described in the above-mentioned “Chemical Handbook Applied Chemistry, Japanese Chemical Society” or “Nippon Kayaku Dye Handbook”.
[0022]
Examples of the pigment include, but are not limited to, inorganic pigments such as carbon black, iron black, chrome vermilion, molybdenum red, red pepper, yellow lead, chrome green, cobalt green, ultramarine blue, and bitumen; phthalocyanine series, azo series And organic pigments such as quinacridone. In addition, since the said pigment may not be introduce | transduced in a raw material particle unless the average particle diameter is 0.4 micrometer or less, it is more preferable to use dye in this case. When the raw material particles are colored, when used as a spacer for a liquid crystal display panel, light leakage of a backlight can be prevented and image quality improvement of the liquid crystal display panel can be achieved.
[0023]
A surface treatment step of surface-treating the generated raw material particles may be further included during and / or after at least one step selected from the above condensation step, polymerization step and heat treatment step.
Although it does not specifically limit as a surface treating agent used for the said surface treatment, The at least 1 sort (s) of silane compound chosen from following General formula (4)-(6) is preferable.
SiX ₄ (4)
R ⁴ SiX ₃ (5)
R ⁵ R ⁶ SiX ₂ (6)
(Wherein X is at least one selected from a chlorine atom, a hydrogen atom, an alkoxy group having 1 to 5 carbon atoms and an acyloxy group having 2 to 5 carbon atoms; each of R ⁴ and R ⁵ has 1 carbon atom) At least one selected from an alkyl group having ˜22 and an aryl group having 6 to 22 carbon atoms, and at least one hydrogen atom in the group is an amino group, mercapto group, alkylene oxide group, epoxy group, cyano group R ⁶ may be substituted with at least one selected from a group, a chlorine atom and a fluorine atom; R ⁶ is at least one monovalent selected from the group consisting of an alkyl group having 1 to 5 carbon atoms and a phenyl group. Group.)
Among the silane compounds, the surface is a silane compound represented by the general formula (4) or a silane compound represented by the general formula (5) or (6) in which R ⁴ and R ⁵ have an amino group as a substituent. Since it is excellent in dry-type dispersibility especially when processed, it is preferable.
[0024]
For example, in the aqueous phase, the raw material particles in the present invention are preferably capable of taking either a positive or negative zeta potential when the pH of the aqueous phase is adjusted. For example, when the raw material particles are the above-described organic-inorganic composite particles, they are positive when the pH is 3 or less, and negative when the pH is 3 to 14.
Further, in order to adjust the pH of the aqueous phase to prepare this zeta potential in more detail and to give the raw material particles a desired charge code and a desired amount of charge, the raw material particles are treated with an appropriate ionic treatment agent. It is preferable to use a raw material containing at least one component selected from an appropriate ionic monomer, a polymerization initiator and an emulsifier.
[0025]
The ionic monomer is not particularly limited, but is preferably the same as the ionic monomer preferably used for the synthesis of the thermoplastic resin fine particles described later, for synthesizing the raw material particles. It is preferable that 0.001-100 wt% is contained in a monomer component, More preferably, it is 0.1-30 wt%, More preferably, it is 0.1-10 wt%. Whether the ionic monomer is excessive or insufficient is not preferable because it causes a problem in heteroaggregation.
The ionic polymerization initiator and the emulsifier are not particularly limited, but various ionic polymerization initiators and emulsifiers such as anionic and cationic can be preferably exemplified.
[0026]
Although it does not necessarily limit as said ionic processing agent, Various ionic surfactant, an ionic polymer, a silane coupling agent, etc. can be mentioned preferably. These ionic treatment agents may be added during the synthesis of the raw material particles, or may be used during the surface treatment after the synthesis.
The ionic monomer and the ionic surfactant may be an amphoteric monomer and an amphoteric surfactant.
(Thermoplastic resin fine particles)
In the adhesive spacer according to the present invention, the adhesive layer is preferably made of thermoplastic resin fine particles, and more preferably one obtained by melting the thermoplastic resin fine particles. The adhesive layer preferably acts as an adhesive for the electrode substrate or the like when the adhesive spacer of the present invention is heated and pressurized.
[0027]
The thermoplastic resin contained in the thermoplastic resin fine particles is not particularly limited as long as it acts as an adhesive as described above. For example, a homopolymer or copolymer of an ethylenically unsaturated monomer is used. Preferred examples include a resin containing a polymer.
The ethylenically unsaturated monomer is not particularly limited. For example, ethylene, propylene, vinyl chloride, vinyl acetate, styrene, vinyl toluene, α-methylstyrene, (meth) acrylic acid ester (for example, methyl ( (Meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl ( Preferable examples include (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate, trifluoropropyl (meth) acrylate, etc. Among these, ethylenically unsaturated monomers are preferred. When a group residue (for example, phenyl group) or a residue capable of hydrogen bonding (ester group or the like) is contained, intermolecular force with the alignment film is increased, and adhesion to the electrode substrate or the like is improved. Since it becomes high, it is preferable, and it is further more preferable that (meth) acrylic ester and / or styrene are included.
[0028]
As the thermoplastic resin, from the viewpoint of further improving the adhesiveness, an epoxy resin, a (meth) acrylic resin containing a (meth) acrylate as a monomer component, a styrene resin containing a styrene compound as a monomer component, and a styrene compound It is particularly preferable to contain at least one selected from various polymer groups consisting of (meth) acrylic-styrene resins containing monomer and (meth) acrylate as monomer components.
When the thermoplastic resin fine particles are produced by polymerizing the (meth) acrylic acid ester and / or styrene, those obtained by soap-free polymerization (soap-free emulsion polymerization) are preferable. The reason is that the soap-free polymerization ( This is because in the soap-free emulsion polymerization), since no conductive impurities such as a surfactant are used, the reliability of the liquid crystal display panel is easily improved.
[0029]
The thermoplastic resin is not limited to the above-mentioned ones. For example, polyesters such as polyethylene terephthalate and polybutylene terephthalate; various polyamides; various polycarbonates; various epoxy resins can be preferably exemplified.
As the thermoplastic resin used for the thermoplastic resin fine particles, these may be used alone or in combination of two or more. The adhesive layer made of thermoplastic resin fine particles may be one layer or two or more layers.
The glass transition temperature (Tg (° C.)) of the thermoplastic resin used for the thermoplastic resin fine particles is preferably 40 to 150 ° C., more preferably 50 to 130 ° C., and particularly preferably 60 to 120 ° C. When the glass transition temperature (Tg (° C.)) of the thermoplastic resin is within the above range, when assembling a liquid crystal display panel, it can be strongly fixed to the electrode substrate even if it is heated and pressurized for a short time. However, when it exceeds 150 ° C., it is not preferable because the thermoplastic resin fine particles are difficult to melt during heating and pressurization, so that the adhesion to the electrode substrate may be insufficient, and less than 40 ° C. Then, when it is used as a spacer, it is not preferable because it may cause fusion between particles during storage or the dispersibility when dispersed on the electrode substrate may deteriorate.
[0030]
The melting start temperature of the thermoplastic resin is preferably 50 to 160 ° C, more preferably 60 to 150 ° C, and still more preferably 70 to 140 ° C. When the melting start temperature is less than 50 ° C., it is not preferable because it may cause fusion during storage or dispersibility when sprayed on the electrode substrate when used as a spacer. If the temperature exceeds 160 ° C., the thermoplastic resin hardly melts during heating and pressurization when assembling the liquid crystal display panel, and therefore, the adhesiveness to the electrode substrate may be insufficient, which is not preferable.
The thermoplastic resin fine particles in the present invention may be colored by including at least one selected from the group consisting of a dye and a pigment, and are not particularly limited. For example, a dye that can be used for coloring spacer raw material particles In addition, the above-mentioned pigments can be preferably exemplified. Further, the color is preferably a color that is difficult to transmit light or that does not transmit light because it can prevent light leakage and improve the contrast of image quality. Examples of colors that are difficult to transmit or do not transmit light include black, dark blue, amber, purple, blue, dark green, green, brown, red, and the like, and particularly preferably black, dark blue The color is amber.
[0031]
The average particle size of the thermoplastic resin fine particles in the present invention is not particularly limited, but is preferably 2 μm or less, more preferably 1 μm or less, and most preferably 0.7 μm or less. When the average particle diameter of the thermoplastic resin fine particles exceeds 2 μm, it may be difficult to coat the raw material particles in the spacer, which is not preferable. In addition, it is preferable to employ | adopt the method similar to the measurement of the average particle diameter of the said raw material particle also as the measuring method of the average particle diameter of this thermoplastic resin fine particle.
The thickness of the adhesive layer made of the thermoplastic resin fine particles in the adhesive spacer of the present invention is not particularly limited, but is usually preferably 0.01 to 2 μm, more preferably 0.05 to 1 μm. If this thickness is smaller than the above range, the adhesiveness may be lowered. If the thickness is larger than the above range, the area covering the alignment film, the color filter, etc. becomes wide, and the display quality of the liquid crystal display plate is lowered. This is not preferable because it may cause
[0032]
The thermoplastic resin fine particles in the present invention are dispersed by post-treatment with an ionic surfactant in order to obtain a desired charge code and a desired charge amount when the pH of the aqueous phase is adjusted, for example, in the aqueous phase. It is preferable to use those synthesized from raw materials containing at least one selected from the group consisting of ionic monomers, polymerization initiators and emulsifiers.
The ionic monomer, the polymerization initiator and the emulsifier are not particularly limited, but at least one ion selected from the group of an anionic or cationic monomer, a polymerization initiator and an emulsifier. The raw material for synthesizing the thermoplastic resin fine particles is preferably contained in an amount of 0.001 to 100 wt%, more preferably 0.01 to 70 wt%, and still more preferably 0.1. ˜25 wt%. If it is less than 0.001 wt%, ionicity is low and heteroaggregation becomes difficult, which is not preferable.
[0033]
The anionic monomer, the polymerization initiator, and the emulsifier are not particularly limited, but preferably include a monomer having a carboxyl group or a sulfone group, a radical polymerization initiator, a surfactant, and the like. Preferred examples of the monomer include acrylic acid, (meth) acrylic acid, maleic acid and sulfostyrene.
The cationic monomer, the polymerization initiator, and the emulsifier are not particularly limited, but an amino group, an amide group, a quaternary ammonium base, and the like can be preferably exemplified. Specifically, N , N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, N-methylaminoethyl methacrylate, N, N-dimethylaminomethyl methacrylate, pN, N-dimethylaminophenyl methacrylate, N, N-dimethylaminoethyl Acrylate, N, N-diethylaminoethyl acrylate, N-methylaminoethyl acrylate, N, N-diethylaminomethyl acrylate, p-N, N-dimethylaminophenyl acrylate; N, N-dimethylaminoethyl methacrylamide, N, N- Diethylami Ethyl methacrylamide, N-methylaminoethyl methacrylamide, N, N-dimethylaminomethyl methacrylamide, pN, N-dimethylaminophenyl methacrylamide, N, N-dimethylaminoethyl acrylamide, N, N-diethylaminoethyl acrylamide N-methylaminoethylacrylamide, N, N-diethylaminomethylacrylamide, pN, N-dimethylaminophenylacrylamide; N, N-dimethylmethacrylamide, N, N-diethylmethacrylamide, N-propylmethacrylamide, N , N-dimethylacrylamide, N, N-diethylacrylamide, N-propylacrylamide; pN, N-dimethylaminostyrene, pN, N-diethylaminostyrene, pN, N-dipropy Aminostyrene, p-N, N-methylaminostyrene; N-vinyldimethylamine, N-vinyldiethylamine, N-vinyldipropylamine, N-vinylpropylamine; vinylbenzyl with amino group at the meta or para position, respectively Alkylamine (the alkyl group is a substituted or unsubstituted alkyl group having 1 to 22 carbon atoms), vinylphenethyl dialkylamine (the alkyl group is a substituted or unsubstituted alkyl group having 1 to 22 carbon atoms); 4-vinylpyridine, 2 Preferred examples include -vinylpyridine, N-vinylimidazole; isopropenyl oxazoline and the like.
[0034]
Furthermore, what was made into the form of the quaternary ammonium salt with respect to the said compound can also be used preferably. For example, what has a C1-C22 alkyl group, a benzyl group, a cycloalkyl group etc. is preferable.
The ionic emulsifier (ionic surfactant) and the ionic monomer may be an amphoteric surfactant and an amphoteric monomer.
(spacer)
In the adhesive spacer for a liquid crystal display panel according to the present invention, the particle structure includes a raw material particle as a particle body and a thermoplastic resin fine particle for forming an adhesive layer attached to at least a part of the surface of the particle. In this structure, the raw material particles as the particle main body and the thermoplastic resin fine particles have different signs of charges (zeta potential) on the particle surface, and are hetero-aggregated by the electrostatic attractive force generated at that time. Become. In addition, it is important to remove the uncoated (unattached) thermoplastic fine particles after heteroaggregation because there is no aggregate of the thermoplastic resin fine particles alone in the subsequent steps. Furthermore, it is preferable to melt at least part of the thermoplastic resin fine particles adhering to the raw material particles after heteroaggregation, but it is not particularly limited. Here, the above-mentioned melting is preferably melting performed by applying an impact force, particularly an impact force by a high-speed air-flow impact method, and the thermoplastic resin (thermoplastic resin fine particles) is stronger on the surface of the raw material particles. Since it becomes the adhesive spacer adhering to, it is preferable.
[0035]
In the adhesive spacer for a liquid crystal display panel according to the present invention, the weight ratio of the raw material particles and the thermoplastic resin fine particles [(thermoplastic resin fine particles / raw material particles) × 100] (wt%) is particularly limited. However, it is preferably 0.1 to 250 wt%, more preferably 1 to 150 wt%, and most preferably 2 to 100 wt%. When the ratio of the thermoplastic resin particles exceeds 250 wt%, the adhesive layer of the obtained adhesive spacer becomes too thick, and the area covering the electrode substrate, the alignment film and the color filter when melted becomes large, and the liquid crystal display On the other hand, if the ratio of the thermoplastic resin powder is less than 0.1 wt%, the adhesiveness may be lowered, which is not preferable.
[0036]
The average particle diameter of the adhesive spacer for liquid crystal display panel obtained by the present invention is not particularly limited, but this average particle diameter is obtained by adding the thickness of the adhesive layer made of thermoplastic resin fine particles to the raw material particles. 1 μm to 32 μm is preferable, more preferably 1 μm to 22 μm, and still more preferably 1.2 μm to 17 μm.
When the adhesive spacer for a liquid crystal display panel according to the present invention is used as an adhesive spacer for a liquid crystal display panel, aggregation of uncoated (unattached) thermoplastic resin fine particles to the raw material particles as the particle body is prevented. Since the uncoated (unattached) thermoplastic resin particles can be removed, there is no aggregate (foreign matter) of the thermoplastic resin particles alone, and the coating efficiency of the thermoplastic resin particles on the raw material particles is high. Therefore, it is possible to efficiently adhere and fix on the electrode substrate, and to improve image quality such as prevention of movement of the spacer itself and an increase in contrast of the liquid crystal display panel.
[0037]
[Method for producing adhesive spacer for liquid crystal display panel]
The method for producing an adhesive spacer for a liquid crystal display panel according to the present invention includes a step of heteroaggregating raw material particles and thermoplastic resin fine particles as a particle main body in an aqueous phase, and the thermoplastic that was not involved in heteroaggregation. And removing the resin fine particles, and it is preferable to cover at least a part of the surface of the raw material particles serving as the particle main body with the adhesive layer made of the thermoplastic resin fine particles by these steps.
In general, heteroaggregation means that when two types of spherical particles having different particle diameters and charge signs are mixed, aggregation between the two particles occurs preferentially, and a composite aggregate in which one is surrounded by the other is formed. Usually, the larger particles are surrounded by the smaller particles, but when the range of the number ratio of both particles is wide, the smaller particles are surrounded by the larger particles. It is also possible to do so.
[0038]
About the process including heteroaggregation in the method for producing an adhesive spacer for liquid crystal display panel of the present invention, the above-mentioned “two kinds of spherical particles having different particle diameters and charge signs” are raw material particles and thermoplastic resin fine particles, The raw material particles are preferably coated so as to be surrounded by the thermoplastic resin fine particles by heteroaggregation due to electrostatic attraction between both particles. In this case, the raw material particles and the thermoplastic resin fine particles are particles themselves. Alternatively, the particles may be subjected to some treatment with an ionic treatment agent or the like.
Specifically, for example, when the pH of the aqueous phase is adjusted, the raw material particles (A1) dispersed using the ionic surfactant (a) and ions having the opposite charge to the ionic surfactant (a) It is synthesized from the thermoplastic resin fine particles (B1) dispersed with the ionic surfactant (b) or the monomer component essentially comprising an ionic monomer having a charge opposite to that of the ionic surfactant. Preferably, in an aqueous phase in which at least one of the thermoplastic resin fine particles (B2) having functional groups / charges derived from the ionic monomer on the particle surface is mixed, static electricity generated by electrostatic interaction between both particles is generated. Heteroaggregation occurs between both particles due to the electric attractive force, and at least a part of the surface of the raw material particles is coated so as to be surrounded by the thermoplastic resin fine particles.
[0039]
In the method for producing an adhesive spacer for a liquid crystal display panel according to the present invention, the ratio of the average particle diameter of the thermoplastic resin fine particles to the raw material particles (thermoplastic resin fine particles / raw material particles) is 1/10000 to 2/5. It is preferable to employ | adopt, More preferably, it is 1 / 1000-3 / 10, More preferably, it is 1 / 100-1 / 5. When the ratio of the average particle diameter is out of the above range, it is not preferable because it may be difficult to cover the raw material particles with the thermoplastic resin fine particles.
In the method for producing an adhesive spacer for a liquid crystal display panel according to the present invention, the zeta potentials of the thermoplastic resin fine particles and the raw material particles are preferably different from each other, and the difference in zeta potential between both particles is It is preferable to set it as 2-300mV, More preferably, it is 10-150mV. If the difference in zeta potential exceeds 300 mV, the system is stable and heteroaggregation does not occur, and it is not preferred, and if it is less than 2 mV, spacer particles cannot be obtained in a monodisperse form even if heteroaggregation occurs.
[0040]
In the method for producing an adhesive spacer for a liquid crystal display panel according to the present invention, the condition and numerical range of the zeta potential can be achieved by adjusting the pH of the aqueous phase (dispersion) so as to satisfy these conditions. Preferably, the thermoplastic resin fine particles and the raw material particles to be used preferably have different signs of charges during heteroaggregation. The ionic surfactant used to disperse the raw material particles in the aqueous phase with respect to the raw material particles, while the ionic surfactant for dispersing the thermoplastic resin fine particles with respect to the thermoplastic resin fine particles. And / or an ionic monomer or polymerization initiator for introducing a functional group on the particle surface is appropriately selected, and after adjusting the pH of the aqueous phase, each particle has a desired charge code and zeta potential. It is preferable that As the ionic monomer and polymerization initiator, those described above as the ionic monomer and polymerization initiator used for the synthesis of the thermoplastic resin fine particles are preferable.
[0041]
In the method for producing an adhesive spacer for a liquid crystal display panel according to the present invention, mixing the raw material particles (including this dispersion liquid) and the thermoplastic resin fine particles (including this dispersion liquid) in the aqueous phase is performed by using the former for the former. In addition, it may be reversed or simultaneous. The pH adjustment of the aqueous phase may be performed either before or after mixing the two.
In the method for producing an adhesive spacer for a liquid crystal display panel according to the present invention, when a step of further adding an electrolyte to the aqueous phase is included, the thermoplastic resin fine particles can be firmly adhered and coated with the raw material particles.
[0042]
As the electrolyte, monovalent, divalent, and trivalent metal salts are preferably used, and more preferably, monovalent metal salts are not particularly limited. Preferable examples include potassium, sodium chloride, lithium chloride, potassium sulfate, sodium sulfate, lithium sulfate and the like. The amount of the electrolyte added is not particularly limited and is arbitrary, but is preferably 1 mol / L or less, more preferably 1 × 10 ⁻⁵ to 1 × 10 ⁻¹ mol / L. However, when the metal salt as described above is used, it is preferably removed during the cleaning process of the spacer particles because it adversely affects the alignment of the liquid crystal as an ionic impurity in the liquid crystal display panel.
[0043]
In the method for producing an adhesive spacer for a liquid crystal display panel according to the present invention, in the step of heteroaggregating, heating at room temperature (about 20 ° C.) or more and (Tg + 50 ° C.) or less during and / or after heteroaggregation. (Here, Tg is the glass transition temperature (Tg (° C.)) of the thermoplastic resin used for the thermoplastic resin fine particles in the present invention). The reason for this is to increase the affinity between the raw material particles and the thermoplastic resin fine particles. In particular, when the heating is performed at a temperature equal to or higher than the Tg (° C.), at least a part of the thermoplastic resin fine particles is melted to form the raw material. Since it adheres firmly to the particle surface, it is possible to reduce peeling of the thermoplastic resin fine particles when the adhesive spacer of the present invention is isolated.
[0044]
The method for producing an adhesive spacer for a liquid crystal display panel according to the present invention further includes a step of removing uncovered (unattached) residual thermoplastic resin fine particles in the aqueous phase after the hetero-aggregating step. Is preferred. In the present invention, since all the thermoplastic resin particles used preferably have the same charge, when they are free in the aqueous phase as uncoated, they repel each other due to electrostatic effects. The particle sizes of the particles that adhere to the surface and become adhesive spacers and the uncoated particles can be clearly distinguished.
In the method for producing an adhesive spacer for a liquid crystal display panel according to the present invention, it is preferable to use a classifier equipped with an electric sieve for removing uncoated residual thermoplastic resin fine particles in the aqueous phase.
[0045]
The electroformed sieve is a screen having a rectangular hole formed by plating. As a method of producing an electroformed sieve, a conductive film is formed on a glass substrate that has been corroded in a highly accurate cross-line shape by physical plating such as vacuum deposition or sputtering, or chemical plating such as electrolytic plating or electroless plating. Then, the plating layer other than the groove of the corroded portion is removed, and a mesh is formed thereon by a method such as electrolytic plating, and then peeled off from the glass original plate. The mesh produced in this manner may be further subjected to electrolytic plating as necessary after peeling from the glass original plate. In addition, as another manufacturing method, after forming a conductive film on a glass plate by vacuum plating, physical plating such as sputtering, or chemical plating such as electrolytic plating or electroless plating, and applying a resist on the film, There is also a method in which a pattern having a predetermined shape is formed, and then portions other than the pattern are removed by etching, and after peeling from the glass original plate, electrolytic plating is performed.
[0046]
As the material of the electric sieve, gold, platinum, silver, copper, iron, aluminum, nickel and various alloys based on these are used. From the durability of the sieve, the corrosion resistance and the ease of plating work. Those mainly composed of nickel are particularly preferably used.
The electrode sieve is not only easy to adjust the aperture diameter and the number of apertures per unit, but also has a very good aperture diameter distribution, so when used as a sieve, it can be classified very accurately. It becomes possible.
Since the electrode sieve is very thin, it can be easily damaged or torn, and there is a risk of mixing metal impurities into the classified particles. In particular, when the classified particles are used for an electronic material such as an adhesive spacer for a liquid crystal display panel of the present invention, the incorporation of metal impurities is a serious problem because it causes deterioration in quality and reliability. For this reason, it is preferable to increase the strength by providing a grid-like or ring-like support on one side or both sides of the electric sieve.
[0047]
With regard to the attachment of the electric sieve to the classifier, particularly when applying ultrasonic vibration, the electric sieve and the classifier are rubbed to break the electric sieve and the metal impurities are mixed into the classified particles. Since there exists a possibility, it is preferable to attach through the member which consists of elastomers.
In the classification step using the electric sieve, it is preferable to perform classification by a wet method by passing the particle dispersion through a classification apparatus equipped with the electric sieve. Compared with the dry method using an inert gas or air as a medium, the wet method has higher ultrasonic irradiation efficiency and dispersion stability, and the particles are less adhered to the electric sieve. In particular, those having a small particle size used for an adhesive spacer for a liquid crystal display panel and the like have strong cohesive force, so that dispersion may be insufficient in the dry method. In the wet method, the liquid medium in which the particles are dispersed can be appropriately selected depending on the material of the electroforming sieve to be used, the aperture diameter, the number of lines, the properties of the particles, the particle size distribution, and the like. In classification, when an ultrasonic irradiation chip is inserted into a classification device, the efficiency of classification can be preferably improved by irradiating a liquid medium such as water with ultrasonic waves.
[0048]
In the method for producing an adhesive spacer for a liquid crystal display panel according to the present invention, the raw material particles and the thermoplastic resin fine particles are heteroaggregated to remove the remaining thermoplastic resin fine particles, and then at least one of the thermoplastic resin fine particles. Although it is preferable to include a melting step of melting the part, it is not particularly limited. Preferred examples of the melting method include a method of performing a heat treatment in the temperature range from the glass transition temperature Tg (° C.) to (Tg + 50 ° C.) and applying an impact force. A method of applying an impact force is more preferable. Among them, a method of applying an impact force by a high-speed air current impact method is particularly preferable. The adoption of the high-speed air-flow impact method is not particularly limited, but “Hybridization System” manufactured by Nara Machinery Co., Ltd. “Mechano-Fusion System” manufactured by Hosokawa Micron Co., Ltd. "Ron system" or the like is preferable, and "Hybridization system" manufactured by Nara Machinery Co., Ltd. is particularly preferable. This is preferable because the thermoplastic resin (thermoplastic resin fine particles) can be more firmly attached to the surface of the raw material particles by the treatment by the impact method in the high-speed air current.
[0049]
Further, in the method for producing an adhesive spacer for a liquid crystal display panel according to the present invention, in order to purify the obtained adhesive spacer, it is classified and purified by the same method as the above-mentioned “step of removing residual thermoplastic resin fine particles”. May be.
[0050]
【Example】
Hereinafter, the present invention will be described more specifically by way of examples. However, the present invention is not limited to these examples. In the following, “parts by weight” may be simply referred to as “parts” for convenience.
First, various particle components used in Examples and Comparative Examples are synthesized by the following Production Examples 1 to 5. Moreover, the average particle diameter (and standard deviation of particle diameter, coefficient of variation of particle diameter) shown in the description of Production Examples 1 to 5 was measured by the following method.
[Average particle size and coefficient of variation of particle size]
The sample was observed with an electron microscope, and the particle diameters of 200 arbitrary samples in the photographed image were measured, and the average particle diameter, the standard deviation of the particle diameter, and the coefficient of variation of the particle diameter were determined according to the following equations.
[0051]
[Expression 1]

[0052]
[Expression 2]

[0053]
[Equation 3]

[0054]
-Production Example 1-
(Organic inorganic composite particles)
By using γ-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane (45/55 weight ratio), co-hydrolysis and polycondensation of alkoxysilyl groups and radical polymerization of double bonds, Organic-inorganic composite particles were obtained and used as raw material particles (A).
When the particle diameter of the raw material particles (A) was observed with an electron microscope and the particle diameter was measured, the average particle diameter was 5.5 μm and the particle diameter variation coefficient was 2.9%. It was 54 wt% (when calcined at 1000 ° C. in air) in terms of SiO _{2 with} respect to the weight of A).
[0055]
-Production Example 2-
(Amino group-containing thermoplastic resin particle dispersion)
In a flask equipped with a stirrer, reflux condenser, nitrogen introduction tube and thermometer, 782.4 parts of deionized water and Haitenol N-08 (Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene nonylphenyl ether ammonium sulfate salt) A 15% aqueous solution of 128 parts was charged and heated to 70 ° C. while gently flowing nitrogen gas. Thereto, 64 parts of a 5% aqueous solution of potassium persulfate was injected, and a monomer mixture consisting of 288 parts of butyl acrylate, 288 parts of styrene and 64 parts of dimethylaminoethyl methacrylate was added dropwise over 3 hours. . During the reaction, nitrogen gas was kept flowing, and the temperature in the flask was kept at 70 ± 1 ° C. After the completion of the dropwise addition, the same temperature was maintained for 2 hours, and then the internal temperature was raised to 80 ° C. and stirring was continued for 1 hour to complete the reaction. Thereafter, the mixture was cooled to obtain an amino group-containing thermoplastic resin fine particle dispersion (B) having a nonvolatile content of 39.8 wt% and a pH of 8.0. Moreover, when the particle diameter of the obtained thermoplastic resin particle dispersion (B) was measured using DLS700 (manufactured by Otsuka Electronics Co., Ltd.) and the zeta potential was measured using ELS-800 (manufactured by Otsuka Electronics Co., Ltd.), the average particle diameter was measured. Was 85 nm and the zeta potential was +53 mV (pH 8.0).
[0056]
-Production Example 3-
(Carboxyl group-containing thermoplastic resin fine particles)
In a flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube and a thermometer, 640 parts of deionized water and Haitenol N-08 (Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene nonylphenyl ether ammonium sulfate salt) 15 A 128% aqueous solution was charged and heated to 70 ° C. while gently flowing nitrogen gas. Thereto, 64 parts of a 5% aqueous solution of potassium persulfate was injected, and a monomer mixture consisting of 320 parts of butyl acrylate, 294.4 parts of methyl methacrylate, and 25.6 parts of acrylic acid was prepared in advance. Added dropwise over 3 hours. During the reaction, nitrogen gas was kept flowing, and the temperature in the flask was kept at 70 ± 1 ° C. After the completion of the dropwise addition, the same temperature was maintained for 2 hours, and then the internal temperature was raised to 80 ° C. and stirring was continued for 1 hour to complete the reaction. Thereafter, the mixture was cooled to obtain a carboxyl group-containing thermoplastic resin particle dispersion (C) having a nonvolatile content of 45.1 wt% and a pH of 2.3. Moreover, when the particle diameter of the obtained thermoplastic resin particle dispersion (C) was measured using DLS700 (manufactured by Otsuka Electronics Co., Ltd.) and the zeta potential was measured using ELS-800 (manufactured by Otsuka Electronics Co., Ltd.), the average particle diameter was measured. Was 103 nm and the zeta potential was -41 mV (pH 2.3).
[0057]
-Production Example 4-
(Oxazoline group-containing thermoplastic resin fine particles)
In a flask equipped with a stirrer, reflux condenser, nitrogen introduction tube and thermometer, 782.4 parts of deionized water and Haitenol N-08 (Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene nonylphenyl ether ammonium sulfate salt) A 15% aqueous solution of 128 parts was charged and heated to 70 ° C. while gently flowing nitrogen gas. Thereto, 64 parts of a 5% aqueous solution of potassium persulfate was injected, and a previously prepared monomer mixture consisting of 288 parts of butyl acrylate, 288 parts of styrene and 64 parts of 2-isopropenyl-2-oxazoline was added. Added dropwise over time. During the reaction, nitrogen gas was kept flowing, and the temperature in the flask was kept at 70 ± 1 ° C. After the completion of the dropwise addition, the same temperature was maintained for 2 hours, and then the internal temperature was raised to 80 ° C. and stirring was continued for 1 hour to complete the reaction. Thereafter, the mixture was cooled to obtain an oxazoline group-containing thermoplastic resin particle dispersion (D) having a nonvolatile content of 39.8 wt% and a pH of 8.0. Moreover, when the particle diameter of the obtained thermoplastic resin fine particle dispersion (D) was measured using DLS700 (manufactured by Otsuka Electronics Co., Ltd.) and the zeta potential was measured using ELS-800 (manufactured by Otsuka Electronics Co., Ltd.), the average particle diameter was measured. Was 85 nm and the zeta potential was +53 mV (pH 8.0).
[0058]
-Production Example 5-
(Anionic thermoplastic resin fine particle dispersion)
A flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube and a thermometer was charged with 576 parts of deionized water, and heated to 70 ° C. while gently flowing nitrogen gas. Thereto, 64 parts of a 20% aqueous solution of potassium persulfate was injected, and a monomer mixture consisting of 80 parts of butyl acrylate, 75 parts of methyl methacrylate and 5 parts of acrylic acid was added dropwise over 2 hours. . During the reaction, nitrogen gas was kept flowing, and the temperature in the flask was kept at 70 ± 1 ° C. After the completion of the dropwise addition, the same temperature was maintained for 2 hours, and then the internal temperature was raised to 80 ° C. and stirring was continued for 1 hour to complete the reaction. Thereafter, the mixture was cooled to obtain an anionic thermoplastic resin particle dispersion liquid dispersion (E) having a nonvolatile content of 19.8 wt% and a pH of 2.3. Moreover, when the particle diameter of the obtained thermoplastic resin fine particle dispersion (E) was measured using DLS700 (manufactured by Otsuka Electronics Co., Ltd.) and the zeta potential was measured using ELS-800 (manufactured by Otsuka Electronics Co., Ltd.), the average particle diameter was measured. Was 450 nm and the zeta potential was −56 mV (pH 2.3).
[0059]
Example 1
When 50 parts of the raw material particles (A) were ultrasonically dispersed in 150 parts of water, the pH was 4.0 and the zeta potential was −20 mV. To 200 parts of this raw material particle dispersion, 200 parts of cationic thermoplastic resin fine particle dispersion (B) was added. The pH of the mixed solution was 7.0, and the zeta potential was +23 mV. This mixed dispersion was charged into a flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube and a thermometer, and heated at 70 ° C. for 2 hours while gently flowing nitrogen gas. When the obtained dispersion mixture was observed with an optical microscope, the aggregates of the system and aggregates of raw material particles made of thermoplastic resin fine particles were not observed, and the thermoplastic resin fine particles alone and the raw material particles were thermoplastic resin fine particles. Only the adhesive spacer (1) coated with was observed.
[0060]
In the classification step, first, the dispersion mixture obtained in the above step was filtered using a membrane filter having a pore size of 1 micron. Only the thermoplastic resin fine particles were present in the liquid after filtration that passed through the filter. The adhesive spacer (1) remaining on the filter side by this filtration was dispersed again using methanol as a dispersion medium, and classified by a classifier equipped with an electroforming sieve. Methanol was appropriately replenished so that the particle concentration in the classifier was maintained at 5 to 20 wt%.
At the time of classification, a nickel-based electroconductive sieve having a pore size of 2.0 μm was used for classification, and then the liquid remaining on the top of the sieve was recovered, and this was further nickel-based and having an aperture diameter of 10.0 μm. Then, classification was performed again, and a dispersion of the classified adhesive spacer (1) that flowed out to the bottom of the sieve was recovered.
[0061]
-Example 2-
In a system in which 100 parts of raw material particles (A) are ultrasonically dispersed in 500 parts of methanol and 20 g of water, 20 parts of a cationic silane coupling agent (manufactured by Shin-Etsu Silicone, product name: X-12-614), ion exchange as a catalyst 1 g of resin was added and reacted for 2 hours at 60 ° C. under methanol reflux. The cationic raw material particles after the reaction were thoroughly washed with methanol and then dried overnight in a vacuum dryer at 100 ° C.
When 50 parts of the cationic raw material particles were ultrasonically dispersed in 150 parts of water, the pH was 8.8 and the zeta potential was +26 mV. To 200 parts of this raw material particle dispersion, 200 parts of an anionic thermoplastic resin fine particle dispersion (C) was added. The pH of the mixed solution was 6.5, and the zeta potential was -16 mV. This mixed dispersion was charged into a flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube and a thermometer, and heated at 70 ° C. for 2 hours while gently flowing nitrogen gas. When the obtained dispersion mixture was observed with an optical microscope, the aggregates of the system and aggregates of raw material particles made of thermoplastic resin fine particles were not observed, and the thermoplastic resin fine particles alone and the raw material particles were thermoplastic resin fine particles. Only the adhesive spacer (2) coated on was observed.
[0062]
In the classification step, filtration, suspension and classification were performed in the same manner as in Example 1, and the dispersion of the adhesive spacer (2) after classification was recovered.
-Example 3-
In a system in which 100 parts of raw material particles (A) are ultrasonically dispersed in 500 parts of methanol and 20 g of water, 20 parts of a cationic silane coupling agent (manufactured by Shin-Etsu Silicone, product name: X-12-614), ion exchange as a catalyst 1 g of resin was added and reacted for 2 hours at 60 ° C. under methanol reflux. The cationic raw material particles after the reaction were thoroughly washed with methanol and then dried overnight in a vacuum dryer at 100 ° C.
[0063]
100 parts of cationic raw material particles were dispersed in 300 parts of an aqueous acetic acid solution adjusted to pH 3, and mixed with 100 parts of an anionic thermoplastic resin particle dispersion (E) to perform heteroaggregation. The obtained heteroaggregated dispersion was fractionated by filtration using a membrane filter having a pore size of 1 μm. Thereafter, the filtered particles were dried overnight at 40 ° C. under reduced pressure. An impact force is applied to 36 parts of the dried particles by a high-speed air-flow impact method using a hybridization system NHS-0 manufactured by Nara Machinery Co., Ltd., and the adhesive layer made of thermoplastic resin fine particles is melted and uniformly coated. The adhesive spacer (3) of Example 3 was obtained.
[0064]
In the classification step, filtration, suspension and classification were performed in the same manner as in Example 1, and the dispersion liquid of the adhesive spacer (3) after classification was recovered.
Example 4
Example 1 and Example 1 except that the oxazoline group-containing thermoplastic resin particle dispersion (D) of Production Example 4 was used instead of the cationic thermoplastic resin particle dispersion (B) used in Example 1. Similarly, an adhesive spacer (4) of Example 4 was obtained.
Also in the classification step, filtration, suspension and classification were performed in the same manner as in Example 1, and the dispersion liquid of the adhesive spacer (4) after classification was recovered.
[0065]
-Comparative Example 1-
After mixing 30 g of raw material particles (A) and 6 g of thermoplastic resin fine particles obtained by drying up the thermoplastic resin fine particle dispersion (C) synthesized in Production Example 3, Nara Machinery Co., Ltd. By using the hybridization system NHS-0 type, the surface of the raw material particles is coated with thermoplastic resin fine particles by the impact method in high-speed air current, thereby obtaining the adhesive spacer of Comparative Example 1 (Comparative Adhesive Spacer (1)). It was.
In the classification step, similar to the step except the filtration step of Example 1, the comparative adhesive spacer (1) is dispersed again using methanol as a dispersion medium, and is performed using an electric sieve, and comparison after classification is performed. A dispersion of the adhesive spacer (1) was collected.
With respect to the adhesive spacers (1) to (4) and the comparative adhesive spacer (1) obtained from Examples 1 to 4 and Comparative Example 1, an adhesion strength test and resin foreign matter evaluation were performed.
[0066]
(Fixing strength test)
The adhesion force (adhesion force) of the adhesive spacer to the substrate after the heat treatment was evaluated by calculating the residual rate of particles before and after air blowing by an air blowing method. The results are shown in Table 1. The residual rate is an average value after three measurements.
Substrate: slide glass heating: heated at 150 ° C. or 180 ° C. for 10 minutes by a hot plate.
Air blow method: An air gun was set at right angles to the slide glass, and air was blown at a pressure of 2 kg / cm ^{2 for} 10 seconds.
[0067]
Number of particles: The number of particles measured is 5000.
[0068]
[Table 1]

[0069]
(Resin foreign matter evaluation)
The filtered and dried sample was observed with an SEM (Hitachi: S3500) in any 5 fields of view (magnification: 1000 times, total number of particles: about 5000). The number of resin foreign matter was measured.
[0070]
[Table 2]

[0071]
【The invention's effect】
According to the present invention, adhesion and aggregation of the thermoplastic resin fine particles are prevented, and the coating efficiency of the thermoplastic resin fine particles on the surface of the raw material particles serving as the spacer particle main body is increased. Can be easily removed, and when used as an adhesive spacer for a liquid crystal display panel, it is possible to provide a novel adhesive spacer for a liquid crystal display panel and a method for producing the same.

Claims (6)

  A method for obtaining an adhesive spacer for a liquid crystal display panel in which at least a part of the surface of a particle main body is coated with an adhesive layer made of a thermoplastic resin, wherein the raw material particles that become the particle main body and the thermoplastic that becomes the adhesive layer A liquid crystal comprising: a step of heteroaggregating resin fine particles with an opposite ionic charge in an aqueous phase; and a step of removing the thermoplastic resin fine particles not involved in heteroaggregation Manufacturing method of adhesive spacer for display panel. The raw material to particles and thermoplastic resin particles, the pH adjustment of the aqueous phase causes give the desired ionic charge, method of manufacturing a liquid crystal display panel for adhesive spacers of claim 1. Desired for the raw material particles by treating the raw material particles with an ionic treating agent or using a raw material containing at least one component selected from an ionic monomer, a polymerization initiator and an emulsifier. The manufacturing method of the adhesive spacer for liquid crystal display panels of Claim 1 or 2 which gives the ionic charge of. The thermoplastic resin fine particles are treated with an ionic surfactant or made using a raw material containing at least one component selected from an ionic monomer, a polymerization initiator, and an emulsifier, thereby producing the heat The method for producing an adhesive spacer for a liquid crystal display panel according to any one of claims 1 to 3 , wherein the plastic resin fine particles have a desired ionic charge. The method for producing an adhesive spacer for a liquid crystal display panel according to any one of claims 1 to 4 , further comprising a melting step of melting at least a part of the thermoplastic resin fine particles adhered to the surface of the raw material particles. The method for producing an adhesive spacer for a liquid crystal display panel according to claim 5 , wherein the melting step is a step of applying an impact force.